title: Engineering

text: Newly emerging branches of science, such as systems biology, are adapting analytical tools traditionally used for engineering, such as systems modeling and computational analysis, to the description of biological systems.


title: Engineering

text: There are connections between engineering and art, for example, architecture, landscape architecture and industrial design (even to the extent that these disciplines may sometimes be included in a university's Faculty of Engineering).


title: Engineering

text: The Art Institute of Chicago, for instance, held an exhibition about the art of NASA's aerospace design. Robert Maillart's bridge design is perceived by some to have been deliberately artistic. At the University of South Florida, an engineering professor, through a grant with the National Science Foundation, has developed a course that connects art and engineering.


title: Engineering

text: Among famous historical figures, Leonardo da Vinci is a well-known Renaissance artist and engineer, and a prime example of the nexus between art and engineering.


title: Engineering

text: Business Engineering deals with the relationship between professional engineering, IT systems, business administration and change management. Engineering management or "Management engineering" is a specialized field of management concerned with engineering practice or the engineering industry sector. The demand for management-focused engineers (or from the opposite perspective, managers with an understanding of engineering), has resulted in the development of specialized engineering management degrees that develop the knowledge and skills needed for these roles. During an engineering management course, students will develop industrial engineering skills, knowledge, and expertise, alongside knowledge of business administration, management techniques, and strategic thinking. Engineers specializing in change management must have in-depth knowledge of the application of industrial and organizational psychology principles and methods. Professional engineers often train as certified management consultants in the very specialized field of management consulting applied to engineering practice or the engineering sector. This work often deals with large scale complex business transformation or Business process management initiatives in aerospace and defence, automotive, oil and gas, machinery, pharmaceutical, food and beverage, electrical & electronics, power distribution & generation, utilities and transportation systems. This combination of technical engineering practice, management consulting practice, industry sector knowledge, and change management expertise enables professional engineers who are also qualified as management consultants to lead major business transformation initiatives. These initiatives are typically sponsored by C-level executives.


title: Engineering

text: In political science, the term "engineering" has been borrowed for the study of the subjects of social engineering and political engineering, which deal with forming political and social structures using engineering methodology coupled with political science principles. Marketing engineering and Financial engineering have similarly borrowed the term.


title: Big O notation

text: Big "O" notation is a mathematical notation that describes the limiting behavior of a function when the argument tends towards a particular value or infinity. Big O is a member of a family of notations invented by Paul Bachmann, Edmund Landau, and others, collectively called Bachmann–Landau notation or asymptotic notation. The letter O was chosen by Bachmann to stand for "Ordnung", meaning the order of approximation.


title: Big O notation

text: In computer science, big O notation is used to classify algorithms according to how their run time or space requirements grow as the input size grows. In analytic number theory, big O notation is often used to express a bound on the difference between an arithmetical function and a better understood approximation; a famous example of such a difference is the remainder term in the prime number theorem. Big O notation is also used in many other fields to provide similar estimates.


title: Big O notation

text: Big O notation characterizes functions according to their growth rates: different functions with the same growth rate may be represented using the same O notation. The letter O is used because the growth rate of a function is also referred to as the order of the function. A description of a function in terms of big O notation usually only provides an upper bound on the growth rate of the function.


title: Big O notation

text: Associated with big O notation are several related notations, using the symbols , and , to describe other kinds of bounds on asymptotic growth rates.


title: Big O notation

text: Let formula_1, the function to be estimated, be a real or complex valued function and let formula_2, the comparison function, be a real valued function. Let both functions be defined on some unbounded subset of the positive real numbers, and formula_3 be strictly positive for all large enough values of formula_4. One writes


title: Big O notation

text: if the absolute value of formula_6 is at most a positive constant multiple of formula_3 for all sufficiently large values of formula_4. That is, formula_9 if there exists a positive real number formula_10 and a real number formula_11 such that


title: Big O notation

text: In many contexts, the assumption that we are interested in the growth rate as the variable formula_4 goes to infinity is left unstated, and one writes more simply that


title: Big O notation

text: The notation can also be used to describe the behavior of formula_1 near some real number formula_16 (often, formula_17): we say


title: Big O notation

text: As formula_3 is chosen to be strictly positive for such values of formula_4, both of these definitions can be unified using the limit superior:


title: Big O notation

text: And in both of these definitions the limit point formula_16 (whether formula_28 or not) is a cluster point of the domains of formula_1 and formula_2, i. e., in every neighbourhood of formula_16 there have to be infinitely many points in common. Moreover, as pointed out in the article about the limit inferior and limit superior, the formula_32 (at least on the extended real number line) always exists.


title: Big O notation

text: In computer science, a slightly more restrictive definition is common: formula_1 and formula_2 are both required to be functions from some unbounded subset of the positive integers to the nonnegative real numbers; then formula_35 iff there exist positive integer numbers formula_10 and formula_37 such that formula_38 for all formula_39.


title: Big O notation

text: In typical usage the notation is asymptotical, that is, it refers to very large . In this setting, the contribution of the terms that grow "most quickly" will eventually make the other ones irrelevant. As a result, the following simplification rules can be applied:


title: Big O notation

text: For example, let , and suppose we wish to simplify this function, using notation, to describe its growth rate as approaches infinity. This function is the sum of three terms: , , and . Of these three terms, the one with the highest growth rate is the one with the largest exponent as a function of , namely . Now one may apply the second rule: is a product of and in which the first factor does not depend on . Omitting this factor results in the simplified form . Thus, we say that is a "big O" of . Mathematically, we can write . One may confirm this calculation using the formal definition: let and . Applying the formal definition from above, the statement that is equivalent to its expansion,


title: Big O notation

text: In both applications, the function appearing within the is typically chosen to be as simple as possible, omitting constant factors and lower order terms.


title: Big O notation

text: This distinction is only in application and not in principle, however—the formal definition for the "big O" is the same for both cases, only with different limits for the function argument.


title: Big O notation

text: Big O notation is useful when analyzing algorithms for efficiency. For example, the time (or the number of steps) it takes to complete a problem of size might be found to be . As grows large, the term will come to dominate, so that all other terms can be neglected—for instance when , the term is 1000 times as large as the term. Ignoring the latter would have negligible effect on the expression's value for most purposes. Further, the coefficients become irrelevant if we compare to any other order of expression, such as an expression containing a term or . Even if , if , the latter will always exceed the former once grows larger than (). Additionally, the number of steps depends on the details of the machine model on which the algorithm runs, but different types of machines typically vary by only a constant factor in the number of steps needed to execute an algorithm. So the big O notation captures what remains: we write either


title: Big O notation

text: and say that the algorithm has "order of " time complexity. The sign "" is not meant to express "is equal to" in its normal mathematical sense, but rather a more colloquial "is", so the second expression is sometimes considered more accurate (see the "Equals sign" discussion below) while the first is considered by some as an abuse of notation.


title: Big O notation

text: Big O can also be used to describe the error term in an approximation to a mathematical function. The most significant terms are written explicitly, and then the least-significant terms are summarized in a single big O term. Consider, for example, the exponential series and two expressions of it that are valid when is small:


title: Big O notation

text: The second expression (the one with "O"("x")) means the absolute-value of the error "e" − (1 + "x" + "x"/2) is at most some constant times |"x"| when "x" is close enough to 0.


title: Big O notation

text: If the function can be written as a finite sum of other functions, then the fastest growing one determines the order of . For example,


title: Big O notation

text: In particular, if a function may be bounded by a polynomial in , then as tends to "infinity", one may disregard "lower-order" terms of the polynomial. The sets and are very different. If is greater than one, then the latter grows much faster. A function that grows faster than for any is called "superpolynomial". One that grows more slowly than any exponential function of the form is called "subexponential". An algorithm can require time that is both superpolynomial and subexponential; examples of this include the fastest known algorithms for integer factorization and the function .


title: Big O notation

text: We may ignore any powers of inside of the logarithms. The set is exactly the same as . The logarithms differ only by a constant factor (since ) and thus the big O notation ignores that. Similarly, logs with different constant bases are equivalent. On the other hand, exponentials with different bases are not of the same order. For example, and are not of the same order.


title: Big O notation

text: Changing units may or may not affect the order of the resulting algorithm. Changing units is equivalent to multiplying the appropriate variable by a constant wherever it appears. For example, if an algorithm runs in the order of , replacing by means the algorithm runs in the order of , and the big O notation ignores the constant . This can be written as . If, however, an algorithm runs in the order of , replacing with gives . This is not equivalent to in general. Changing variables may also affect the order of the resulting algorithm. For example, if an algorithm's run time is when measured in terms of the number of "digits" of an input number , then its run time is when measured as a function of the input number itself, because .


title: Big O notation

text: If formula_49 and formula_50 then formula_51. It follows that if formula_52 and formula_53 then formula_54. In other words, this second statement says that formula_55 is a convex cone.


title: Big O notation

text: Big "O" (and little o, Ω, etc.) can also be used with multiple variables. To define big "O" formally for multiple variables, suppose formula_1 and formula_2 are two functions defined on some subset of formula_61. We say


title: Big O notation

text: if and only if there exist constants formula_10 and formula_64 such that formula_65 for all formula_66 with formula_67 for some formula_68


title: Big O notation

text: Equivalently, the condition that formula_69 for some formula_70 can be written formula_71, where formula_72 denotes the Chebyshev norm. For example, the statement


title: Big O notation

text: whenever either formula_75 or formula_76 holds. This definition allows all of the coordinates of formula_66 to increase to infinity. In particular, the statement


title: Big O notation

text: Under this definition, the subset on which a function is defined is significant when generalizing statements from the univariate setting to the multivariate setting. For example, if formula_82 and formula_83, then formula_84 if we restrict formula_1 and formula_2 to formula_87, but not if they are defined on formula_88.


title: Big O notation

text: This is not the only generalization of big O to multivariate functions, and in practice, there is some inconsistency in the choice of definition.


title: Big O notation

text: The statement ""f"("x") is "O"("g"("x"))" as defined above is usually written as . Some consider this to be an abuse of notation, since the use of the equals sign could be misleading as it suggests a symmetry that this statement does not have. As de Bruijn says, is true but is not. Knuth describes such statements as "one-way equalities", since if the sides could be reversed, "we could deduce ridiculous things like from the identities and ." In another letter, Knuth also pointed out that "the equality sign is not symmetric with respect to such notations", as, in this notation, "mathematicians customarily use the = sign as they use the word "is" in English: Aristotle is a man, but a man isn't necessarily Aristotle".


title: Big O notation

text: For these reasons, it would be more precise to use set notation and write (read as: ""f"("x") "is an element of" "O"("g"("x"))", or ""f"("x") "is in the set" "O"("g"("x"))"), thinking of "O"("g"("x")) as the class of all functions "h"("x") such that |"h"("x")| ≤ "C"|"g"("x")| for some constant "C". However, the use of the equals sign is customary.


title: Big O notation

text: Big O notation can also be used in conjunction with other arithmetic operators in more complicated equations. For example, denotes the collection of functions having the growth of "h"("x") plus a part whose growth is limited to that of "f"("x"). Thus,


title: Big O notation

text: Suppose an algorithm is being developed to operate on a set of "n" elements. Its developers are interested in finding a function "T"("n") that will express how long the algorithm will take to run (in some arbitrary measurement of time) in terms of the number of elements in the input set. The algorithm works by first calling a subroutine to sort the elements in the set and then perform its own operations. The sort has a known time complexity of "O"("n"), and after the subroutine runs the algorithm must take an additional steps before it terminates. Thus the overall time complexity of the algorithm can be expressed as . Here the terms are subsumed within the faster-growing "O"("n"). Again, this usage disregards some of the formal meaning of the "=" symbol, but it does allow one to use the big O notation as a kind of convenient placeholder.


title: Big O notation

text: In more complicated usage, "O"(·) can appear in different places in an equation, even several times on each side. For example, the following are true for formula_91:


title: Big O notation

text: The meaning of such statements is as follows: for "any" functions which satisfy each "O"(·) on the left side, there are "some" functions satisfying each "O"(·) on the right side, such that substituting all these functions into the equation makes the two sides equal. For example, the third equation above means: "For any function "f"("n") = "O"(1), there is some function "g"("n") = "O"("e") such that "n" = "g"("n")." In terms of the "set notation" above, the meaning is that the class of functions represented by the left side is a subset of the class of functions represented by the right side. In this use the "=" is a formal symbol that unlike the usual use of "=" is not a symmetric relation. Thus for example does not imply the false statement .


title: Big O notation

text: Big O is typeset as an italicized uppercase "O", as in the following example: formula_93. In TeX, it is produced by simply typing O inside math mode. Unlike Greek-named Bachmann–Landau notations, it needs no special symbol. Yet, some authors use the calligraphic variant formula_94 instead.


title: Big O notation

text: Here is a list of classes of functions that are commonly encountered when analyzing the running time of an algorithm. In each case, "c" is a positive constant and "n" increases without bound. The slower-growing functions are generally listed first.


title: Big O notation

text: The statement formula_95 is sometimes weakened to formula_96 to derive simpler formulas for asymptotic complexity. For any formula_97 and formula_98 is a subset of formula_99 for any so may be considered as a polynomial with some bigger order.


title: Big O notation

text: Big "O" is widely used in computer science. Together with some other related notations it forms the family of Bachmann–Landau notations.


title: Big O notation

text: Intuitively, the assertion " is " (read " is little-o of ") means that grows much faster than . As before, let "f" be a real or complex valued function and "g" a real valued function, both defined on some unbounded subset of the positive real numbers, such that "g"("x") is strictly positive for all large enough values of "x". One writes


title: Big O notation

text: The difference between the definition of the big-O notation and the definition of little-o is that while the former has to be true for "at least one" constant "M", the latter must hold for "every" positive constant , however small. In this way, little-o notation makes a "stronger statement" than the corresponding big-O notation: every function that is little-o of "g" is also big-O of "g", but not every function that is big-O of "g" is also little-o of "g". For example, formula_106 but


title: Big O notation

text: As "g"("x") is nonzero, or at least becomes nonzero beyond a certain point, the relation formula_107 is equivalent to


title: Big O notation

text: Another asymptotic notation is formula_117, read "big omega". There are two widespread and incompatible definitions of the statement


title: Big O notation

text: where "a" is some real number, ∞, or −∞, where "f" and "g" are real functions defined in a neighbourhood of "a", and where "g" is positive in this neighbourhood.


title: Big O notation

text: The Hardy–Littlewood definition is used mainly in analytic number theory, and the Knuth definition mainly in computational complexity theory; the definitions are not equivalent.


title: Big O notation

text: In 1914 Godfrey Harold Hardy and John Edensor Littlewood introduced the new symbol formula_117, which is defined as follows:


title: Big O notation

text: These symbols were used by Edmund Landau, with the same meanings, in 1924. After Landau, the notations were never used again exactly thus; formula_126 became formula_135 and formula_127 became formula_137.


title: Big O notation

text: These three symbols formula_138, as well as formula_139 (meaning that formula_140 and formula_141 are both satisfied), are now currently used in analytic number theory.


title: Big O notation

text: In 1976 Donald Knuth published a paper to justify his use of the formula_117-symbol to describe a stronger property. Knuth wrote: "For all the applications I have seen so far in computer science, a stronger requirement ... is much more appropriate". He defined


title: Big O notation

text: with the comment: "Although I have changed Hardy and Littlewood's definition of formula_117, I feel justified in doing so because their definition is by no means in wide use, and because there are other ways to say what they want to say in the comparatively rare cases when their definition applies."


title: Big O notation

text: The limit definitions assume formula_155 for sufficiently large formula_156. The table is (partly) sorted from smallest to largest, in the sense that formula_157 (Knuth's version of) formula_158 on functions correspond to formula_159formula_160 on the real line (the Hardy–Littlewood version of formula_161, however, doesn't correspond to any such description).


title: Big O notation

text: Computer science uses the big formula_162, big Theta formula_163, little formula_164, little omega formula_165 and Knuth's big Omega formula_161 notations. Analytic number theory often uses the big formula_162, small formula_164, Hardy–Littlewood's big Omega formula_161 (with or without the +, − or ± subscripts) and formula_170 notations. The small omega formula_165 notation is not used as often in analysis.


title: Big O notation

text: Informally, especially in computer science, the big "O" notation often can be used somewhat differently to describe an asymptotic tight bound where using big Theta Θ notation might be more factually appropriate in a given context. For example, when considering a function "T"("n") = 73"n" + 22"n" + 58, all of the following are generally acceptable, but tighter bounds (such as numbers 2 and 3 below) are usually strongly preferred over looser bounds (such as number 1 below).


title: Big O notation

text: So while all three statements are true, progressively more information is contained in each. In some fields, however, the big O notation (number 2 in the lists above) would be used more commonly than the big Theta notation (items numbered 3 in the lists above). For example, if "T"("n") represents the running time of a newly developed algorithm for input size "n", the inventors and users of the algorithm might be more inclined to put an upper asymptotic bound on how long it will take to run without making an explicit statement about the lower asymptotic bound.


title: Big O notation

text: In their book "Introduction to Algorithms", Cormen, Leiserson, Rivest and Stein consider the set of functions "f" which satisfy


title: Big O notation

text: The authors state that the use of equality operator (=) to denote set membership rather than the set membership operator (∈) is an abuse of notation, but that doing so has advantages. Inside an equation or inequality, the use of asymptotic notation stands for an anonymous function in the set "O"("g"), which eliminates lower-order terms, and helps to reduce inessential clutter in equations, for example:


title: Big O notation

text: Another notation sometimes used in computer science is Õ (read "soft-O"): "f"("n") = "Õ"("g"("n")) is shorthand for for some "k". Some authors write O for the same purpose. Essentially, it is big O notation, ignoring logarithmic factors because the growth-rate effects of some other super-logarithmic function indicate a growth-rate explosion for large-sized input parameters that is more important to predicting bad run-time performance than the finer-point effects contributed by the logarithmic-growth factor(s). This notation is often used to obviate the "nitpicking" within growth-rates that are stated as too tightly bounded for the matters at hand (since log "n" is always "o"("n") for any constant "k" and any ).


title: Big O notation

text: The generalization to functions taking values in any normed vector space is straightforward (replacing absolute values by norms), where "f" and "g" need not take their values in the same space. A generalization to functions "g" taking values in any topological group is also possible.


title: Big O notation

text: The "limiting process" "x" → "x" can also be generalized by introducing an arbitrary filter base, i.e. to directed nets "f" and "g". The "o" notation can be used to define derivatives and differentiability in quite general spaces, and also (asymptotical) equivalence of functions,


title: Big O notation

text: which is an equivalence relation and a more restrictive notion than the relationship ""f" is Θ("g")" from above. (It reduces to lim "f" / "g" = 1 if "f" and "g" are positive real valued functions.) For example, 2"x" is Θ("x"), but is not "o"("x").


title: Big O notation

text: The symbol O was first introduced by number theorist Paul Bachmann in 1894, in the second volume of his book "Analytische Zahlentheorie" ("analytic number theory"). The number theorist Edmund Landau adopted it, and was thus inspired to introduce in 1909 the notation o; hence both are now called Landau symbols. These notations were used in applied mathematics during the 1950s for asymptotic analysis.


title: Big O notation

text: The symbol formula_117 (in the sense "is not an "o" of") was introduced in 1914 by Hardy and Littlewood. Hardy and Littlewood also introduced in 1916 the symbols formula_126 ("right") and formula_127 ("left"), precursors of the modern symbols formula_135 ("is not smaller than a small o of") and formula_137 ("is not larger than a small o of"). Thus the Omega symbols (with their original meanings) are sometimes also referred to as "Landau symbols". This notation formula_117 became commonly used in number theory at least since the 1950s.


title: Big O notation

text: In the 1970s the big O was popularized in computer science by Donald Knuth, who introduced the related Theta notation, and proposed a different definition for the Omega notation.


title: Big O notation

text: (Hardy however never defined or used the notation formula_185, nor formula_186, as it has been sometimes reported).


title: Big O notation

text: Hardy introduced the symbols formula_187 and formula_188 (as well as some other symbols) in his 1910 tract "Orders of Infinity", and made use of them only in three papers (1910–1913). In his nearly 400 remaining papers and books he consistently used the Landau symbols O and o.


title: Big O notation

text: Hardy's notation is not used anymore. On the other hand, in the 1930s, the Russian number theorist Ivan Matveyevich Vinogradov introduced his notation formula_186, which has been increasingly used in number theory instead of the formula_190 notation. We have


title: Big O notation

text: The big-O originally stands for "order of" ("Ordnung", Bachmann 1894), and is thus a Latin letter. Neither Bachmann nor Landau ever call it "Omicron". The symbol was much later on (1976) viewed by Knuth as a capital omicron, probably in reference to his definition of the symbol Omega. The digit zero should not be used.


title: Robert Blake (actor)

text: Robert Blake (born Michael James Gubitosi; September 18, 1933) is an American retired actor known for his roles in the 1967 film "In Cold Blood" and the 1970s U.S. television series "Baretta".


title: Robert Blake (actor)

text: Blake began acting as a child, with a lead role in the final years of Metro-Goldwyn-Mayer's "Our Gang" ("Little Rascals") short film series from 1939 to 1944. He also appeared as a child actor in 22 entries of the "Red Ryder" film franchise. In the "Red Ryder" series and in many of his adult roles, the Italian-American actor was often cast as an American Indian or Latino character. After a stint in the United States Army, Blake returned to acting in both television and movie roles. Blake continued acting until 1997's "Lost Highway". Owing to Blake becoming one of the first child actors to successfully transition to mature roles as an adult, author Michael Newton called his career "one of the longest in Hollywood history."


title: Robert Blake (actor)

text: In March 2005, Blake was tried and acquitted of the 2001 murder of his second wife, Bonny Lee Bakley. In November 2005, he was found liable in a California civil court for her wrongful death.


title: Robert Blake (actor)

text: Robert Blake was born Michael James Gubitosi in Nutley, New Jersey, on September 18, 1933. His parents were Giacomo (James) Gubitosi and his wife, Elizabeth Cafone. In 1930, James worked as a die setter for a can manufacturer. Eventually, Blake's parents began a song-and-dance act. In 1936, their three children began performing, billed as "The Three Little Hillbillies." They moved to Los Angeles, California, in 1938, where their children began working as movie extras.


title: Robert Blake (actor)

text: Blake had an unhappy childhood in which he was abused by his alcoholic father. When he entered public school at age 10, he was bullied and had fights with other students, which led to his expulsion. Blake stated that he was physically and sexually abused by both of his parents while growing up and was frequently locked in a closet and forced to eat off the floor as punishment. At age 14, he ran away from home, leading to several more difficult years. His father died by suicide in 1956.


title: Robert Blake (actor)

text: Then known as "Mickey Gubitosi", Blake began his acting career as Toto in the MGM movie "Bridal Suite" (1939), starring Annabella and Robert Young. Blake then began appearing in MGM's "Our Gang" short subjects (a.k.a. "The Little Rascals") under his real name, replacing Eugene "Porky" Lee. He appeared in 40 of the shorts between 1939 and 1944, eventually becoming the series' final lead character. Blake's parents also made appearances in the series as extras. In "Our Gang", Blake's character, Mickey, was often called upon to cry, for which he was criticized for being unconvincing. He was also criticized for being obnoxious and whiny. In 1942, he acquired the stage name "Bobby Blake" and his character in the series was renamed "Mickey Blake." In 1944, MGM discontinued "Our Gang", releasing the final short in the series, "Dancing Romeo". In 1995, Blake was honored by the Young Artist Foundation with its Former Child Star "Lifetime Achievement" Award for his role in "Our Gang". In 1942, Blake appeared as "Tooky" Stedman in "Andy Hardy's Double Life".


title: Robert Blake (actor)

text: In 1944, Blake began playing a Native American boy, "Little Beaver," in the "Red Ryder" western series at the studios of Republic Pictures (now CBS Radford Studios), appearing in twenty-three of the movies until 1947. He also had roles in one of Laurel and Hardy's later films "The Big Noise" (1944), and the Warner Bros. movies "Humoresque" (1946), playing John Garfield's character as a child, and "The Treasure of the Sierra Madre" (1948), playing the Mexican boy who sells Humphrey Bogart a winning lottery ticket and gets a glass of water thrown in his face by Bogart in the process. In 1950, at age 17, Blake appeared as Mahmoud in "The Black Rose" and as Enrico, Naples Bus Boy (uncredited) in "Black Hand".


title: Robert Blake (actor)

text: In 1950, Blake was drafted into the United States Army. Upon leaving at the age of 21, he found himself without any job prospects and fell into a deep depression. This led to a two-year addiction to heroin and cocaine. He also sold drugs. Blake entered Jeff Corey's acting class and began working on improving his personal and professional life. He eventually became a seasoned Hollywood actor, playing notable dramatic roles in movies and on television. In 1956, he was billed as Robert Blake for the first time.


title: Robert Blake (actor)

text: In 1959, Blake turned down the role of Little Joe Cartwright, a character ultimately portrayed by Michael Landon, in NBC's western television series "Bonanza." He did appear that year as Tobe Hackett in the episode "Trade Me Deadly" of the syndicated western series "26 Men," which dramatized true stories of the Arizona Rangers. Blake also appeared twice as "Alfredo" in the syndicated western "The Cisco Kid" and starred in "The White Hat" episode of "Men of Annapolis," another syndicated series. He appeared in three distinctive guest lead roles in the CBS series "Have Gun Will Travel", as well as one-time guest roles on John Payne's NBC western "The Restless Gun", Nick Adams's ABC western "The Rebel", and in season 3, episode 25 of "Bat Masterson", the NBC western series "The Californians", the short-lived ABC adventure series "Straightaway", and the NBC western television series "Laramie".


title: Robert Blake (actor)

text: Blake performed in numerous motion pictures as an adult, including the starring role in "The Purple Gang" (1960), a gangster movie, and featured roles in "Pork Chop Hill" (1959) and, as one of four U.S. soldiers participating in a gang rape in occupied Germany, in "Town Without Pity" (1961). He was also in "Ensign Pulver" (1964), "The Greatest Story Ever Told" (1965) and other films.


title: Robert Blake (actor)

text: Blake garnered further exposure as a member of the ensemble cast of the 1963 acclaimed but short-lived "The Richard Boone Show", appearing in fifteen of the NBC series' 25 episodes. At 33, Blake played Billy the Kid in the 1966 episode "The Kid from Hell's Kitchen" of the syndicated western series "Death Valley Days", hosted by Robert Taylor. In the story line, The Kid sets out to avenge the death of his friend John Tunstall played by John Anderson.


title: Robert Blake (actor)

text: In 1967, Blake experienced a career breakout due to his work in the film "In Cold Blood". Blake played real-life murderer Perry Smith, to whom he bore a chilling resemblance. Richard Brooks received two Oscar nominations for the film: one for his direction, and one for his adaptation of Truman Capote's book.With "In Cold Blood", Blake was the first actor to utter the expletive "bull----" in a mainstream American motion picture.


title: Robert Blake (actor)

text: Blake played a Native American fugitive in "Tell Them Willie Boy Is Here" (1969), starred in a TV movie adaptation of "Of Mice and Men" (1981), and played a motorcycle highway patrolman in iconoclastic "Electra Glide in Blue" (1973). He played a small-town stock car driver with ambitions to join the NASCAR circuit in "Corky, " which MGM produced in 1972. The film featured real NASCAR drivers, including Richard Petty and Cale Yarborough.


title: Robert Blake (actor)

text: Blake may be best known for his Emmy Award-winning role of Tony Baretta in the popular television series "Baretta" (1975 to 1978), playing a street-wise, plain clothes police detective. The show's trademarks included Baretta's pet cockatoo "Fred" and his signature phrases—notably "Don't do the crime if you can't do the time", "That's the name of that tune", and "You can take that to the bank."


title: Robert Blake (actor)

text: After "Baretta" ended, NBC offered to produce several pilot episodes of a proposed series titled "Joe Dancer", in which Blake would play the role of a hard-boiled private detective. In addition to starring, Blake also was credited as the executive producer and creator. Three television films aired on NBC in 1981 and 1983, and the series never ultimately sold.


title: Robert Blake (actor)

text: Blake had starring roles in a couple of films for Paramount Pictures, "Coast to Coast" (1980) and "Second-Hand Hearts" (1981). He continued to act through the 1980s and 1990s, mostly in television, in such roles as Jimmy Hoffa in the miniseries "Blood Feud" (1983) and as John List in the murder drama "" (1993), which earned him a third Emmy nomination. Blake starred in the 1985 television series "Hell Town", playing a priest working in a tough neighborhood. He also had character parts in the theatrical movies "Money Train" (1995) and played the Mystery Man in David Lynch's "Lost Highway" (1997).


title: Robert Blake (actor)

text: Blake and actress Sondra Kerr were married in 1961, and divorced in 1983. It was his first marriage, from which came two children: actor Noah Blake (born 1965) and Delinah Blake (born 1966).


title: Robert Blake (actor)

text: In 1999, Blake met Bonny Lee Bakley, formerly of Wharton, New Jersey, who had already been married nine times and reportedly had a history of exploiting older men, especially celebrities, for money. She was dating Christian Brando, the son of Marlon Brando, during her relationship with Blake. Bakley became pregnant and told both Brando and Blake that her baby was theirs. Initially, Bakley named the baby "Christian Shannon Brando" and stated that Brando was the father. Bakley wrote letters describing her dubious motives to Blake. Blake insisted that she take a DNA test to prove the paternity. Blake became Bakley's tenth husband on November 19, 2000, after DNA tests proved that Blake was the biological father of her child, who was renamed Rosie. Blake remained married to Bakley until she was murdered on May 4, 2001.


title: Robert Blake (actor)

text: In a March 2016 interview at age 82, Blake indicated he had a new woman in his life, who remained unnamed. In 2017, Blake applied for a marriage license for his fiancée, Pamela Hudak, whom he had known for decades, and who had testified on his behalf at his trial. On December 7, 2018, it was announced that Blake had filed for divorce.


title: Robert Blake (actor)

text: On May 4, 2001, Blake took Bakley out for dinner at Vitello's Italian Restaurant at 4349 Tujunga Avenue in Studio City, California. Bakley was fatally shot in the head while sitting in Blake's vehicle, which was parked on a side street around the corner from the restaurant, across the street and behind a dumpster next to a construction site. Blake claimed that he had returned to the restaurant to collect a pistol which he had left inside and claimed that he had not been present when the shooting took place. The pistol Blake claimed to have left in the restaurant was later found and determined by police not to be the murder weapon.


title: Robert Blake (actor)

text: On April 18, 2002, Blake was arrested and charged with Bakley's murder. His longtime bodyguard, Earle Caldwell, was also arrested and charged with conspiracy in connection with the murder. A key event that gave the Los Angeles Police Department the confidence to arrest Blake came when a retired stuntman, Ronald "Duffy" Hambleton, agreed to testify against him. Hambleton alleged that Blake tried to hire him to kill Bakley. Another retired stuntman and an associate of Hambleton's, Gary McLarty, also came forward with a similar story. According to author Miles Corwin, Hambleton had agreed to testify against Blake only after being told that he would be subject to a grand jury subpoena and a misdemeanor charge.


title: Robert Blake (actor)

text: On April 22, 2002, Blake was charged with one count of murder with special circumstances, an offense which carried a possible death penalty. He was also charged with two counts of solicitation of murder and one count of conspiracy to commit murder. Blake entered a plea of not guilty. On March 13, 2003, after almost a year in jail, Blake was granted bail, which was set at $1.5 million. He was then placed under house arrest while awaiting trial. On October 31, in a major reversal for the prosecution, the judge dismissed the conspiracy charges against Blake and Caldwell during a pre-trial hearing. The junior prosecutor who handled the case, Shellie Samuels, was interviewed by CBS reporter Peter Van Sant for the CBS program "48 Hours Investigates". During the interview, broadcast in November 2003, she admitted that the prosecutors had no forensic evidence implicating Blake in the murder and that they could not tie him to the murder weapon.


title: Robert Blake (actor)

text: Blake's criminal trial for murder began on December 20, 2004, with opening statements by the prosecution and opening statements by the defense the following day. The prosecution contended that Blake intentionally murdered Bakley to free himself from a loveless marriage, while the defense claimed that Blake was an innocent victim of circumstantial and fabricated evidence. McLarty and Hambleton each testified that Blake had asked them to murder Bakley. On cross-examination, the defense brought up McLarty's mental health problems and Hambleton's criminal history. The lack of gunshot residue on Blake's hands was a key part of the defense's case that Blake was not the shooter. Blake chose not to testify.


title: Robert Blake (actor)

text: On March 16, 2005, Blake was found not guilty of murder and not guilty of one of the two counts of solicitation of murder. The other count, for solicitation to commit murder, was dropped after it was revealed that the jury was deadlocked 11–1 in favor of an acquittal. Los Angeles District Attorney Stephen Cooley, commenting on this ruling, called Blake "a miserable human being" and the jurors "incredibly stupid" to fall for the defense's claims. Public opinion regarding the verdict was mixed, with some feeling that Blake was guilty, though many felt that there was not enough evidence to convict him. On the night of his acquittal several fans celebrated at Blake's favorite haunt – and the scene of the crime – Vitello's.


title: Robert Blake (actor)

text: Bakley's three children filed a civil suit against Blake, asserting that he was responsible for their mother's death. During the trial, the girlfriend of Blake's co-defendant Earle Caldwell said she believed Blake and Caldwell were involved in the crime.


title: Robert Blake (actor)

text: On November 18, 2005, a jury found Blake liable for the wrongful death of his wife and ordered him to pay $30 million. On February 3, 2006, Blake filed for bankruptcy.


title: Robert Blake (actor)

text: Blake's attorney, M. Gerald Schwartzbach, appealed the court's decision on February 28, 2007. On April 26, 2008, an appeals court upheld the civil case verdict, but cut Blake's penalty assessment to $15 million.


title: Robert Blake (actor)

text: Blake has maintained a low profile since his acquittal and filing for bankruptcy, with debts of $3 million for unpaid legal fees as well as state and federal taxes. Due to his legal problems Blake has said that he might return to acting someday in order to help himself financially. On April 9, 2010, the state of California filed a tax lien against Blake for $1,110,878 in unpaid back taxes.


title: Robert Blake (actor)

text: On July 16, 2012, Blake was interviewed on CNN's "Piers Morgan Tonight". When Piers Morgan asked Blake about the night of Bakley's murder, Blake became defensive and angry, stating he resented Morgan's questioning and felt he was being interrogated. Morgan responded he was only asking questions that he felt people were eager to have answered.


title: Robert Blake (actor)

text: In January 2019, Blake was interviewed by "20/20". Initially he seemed to decline the interview and instead delegated it to a friend, but then began to participate, discussing the murder and the behavior of the police officers who dealt with him, the culture of Hollywood and its reaction to the event, and his early life and difficulties with his parents.


title: Robert Blake (actor)

text: In September 2019, Blake started a YouTube channel titled 'Robert Blake: I ain't dead yet, so stay tuned,' in which he discusses his life and career.


title: Robert Blake (actor)

text: Later in October the same year, Blake's daughter, Rose Lenore, opened up about her childhood and how the trial affected her. She discussed reuniting with her father, visiting her mother's grave and her own desire to get into acting. Regarding knowing the truth about her mother's murder and whether Blake did it she declined to know the details but is open to knowing the truth "If it's ever an option".


title: Robert Blake (actor)

text: In 2021, Blake opened up a website, "Robert Blake's Pushcart", where scripts, memorabilia and books including his autobiography 'Tales of a Rascal' are available to read and in the case of the latter can be ordered. The website has since closed down and its name has been taken by an unrelated towing service.


title: Robert Blake (actor)

text: Quentin Tarantino's novel of "Once Upon a Time in Hollywood" based on his film of the same name is dedicated to Blake. Notably Blake's later life dealing with his wife's murder mirrors Brad Pitt's character Cliff Booth who is also accused of murdering his wife.


title: Escherichia coli

text: Escherichia coli (), also known as E. coli (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus "Escherichia" that is commonly found in the lower intestine of warm-blooded organisms. Most "E. coli" strains are harmless, but some serotypes (EPEC, ETEC etc.) can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains do not cause disease in humans and are part of the normal microbiota of the gut; such strains are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of "E. coli" benefit their hosts by producing vitamin K or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between "E. coli" and humans are a type of mutualistic biological relationship — where both the humans and the "E. coli" are benefitting each other. "E. coli" is expelled into the environment within fecal matter. The bacterium grows massively in fresh faecal matter under aerobic conditions for three days, but its numbers decline slowly afterwards.


title: Escherichia coli

text: "E. coli" and other facultative anaerobes constitute about 0.1% of gut microbiota, and fecal–oral transmission is the major route through which pathogenic strains of the bacterium cause disease. Cells are able to survive outside the body for a limited amount of time, which makes them potential indicator organisms to test environmental samples for fecal contamination. A growing body of research, though, has examined environmentally persistent "E. coli" which can survive for many days and grow outside a host.


title: Escherichia coli

text: The bacterium can be grown and cultured easily and inexpensively in a laboratory setting, and has been intensively investigated for over 60 years. "E. coli" is a chemoheterotroph whose chemically defined medium must include a source of carbon and energy. "E. coli" is the most widely studied prokaryotic model organism, and an important species in the fields of biotechnology and microbiology, where it has served as the host organism for the majority of work with recombinant DNA. Under favourable conditions, it takes as little as 20 minutes to reproduce.


title: Escherichia coli

text: "E. coli" is a Gram-negative, facultative anaerobe, nonsporulating coliform bacterium. Cells are typically rod-shaped, and are about 2.0 μm long and 0.25–1.0 μm in diameter, with a cell volume of 0.6–0.7 μm. Antibiotics can effectively treat "E. coli" infections outside the digestive tract and most intestinal infections but are not used to treat intestinal infections by one strain of these bacteria. The flagella which allow the bacteria to swim have a peritrichous arrangement. It also attaches and effaces to the microvilli of the intestines via an adhesion molecule known as intimin.


title: Escherichia coli

text: "E. coli" can live on a wide variety of substrates and uses mixed acid fermentation in anaerobic conditions, producing lactate, succinate, ethanol, acetate, and carbon dioxide. Since many pathways in mixed-acid fermentation produce hydrogen gas, these pathways require the levels of hydrogen to be low, as is the case when "E. coli" lives together with hydrogen-consuming organisms, such as methanogens or sulphate-reducing bacteria.


title: Escherichia coli

text: In addition, "E. coli"s metabolism can be rewired to solely use CO as the source of carbon for biomass production. In other words, this obligate heterotroph's metabolism can be altered to display autotrophic capabilities by heterologously expressing carbon fixation genes as well as formate dehydrogenase and conducting laboratory evolution experiments. This may be done by using formate to reduce electron carriers and supply the ATP required in anabolic pathways inside of these synthetic autotrophs.


title: Escherichia coli

text: "E. coli" have three native glycolytic pathways: EMPP, EDP, and OPPP. The EMPP employs ten enzymatic steps to yield two pyruvates, two ATP, and two NADH per glucose molecule while OPPP serves as an oxidation route for NADPH synthesis. Although the EDP is the more thermodynamically favourable of the three pathways, "E. coli" do not use the EDP for glucose metabolism, relying mainly on the EMPP and the OPPP. The EDP mainly remains inactive except for during growth with gluconate.


title: Escherichia coli

text: When growing in the presence of a mixture of sugars, bacteria will often consume the sugars sequentially through a process known as catabolite repression. By repressing the expression of the genes involved in metabolizing the less preferred sugars, cells will usually first consume the sugar yielding the highest growth rate, followed by the sugar yielding the next highest growth rate, and so on. In doing so the cells ensure that their limited metabolic resources are being used to maximize the rate of growth. The well-used example of this with "E. coli" involves the growth of the bacterium on glucose and lactose, where "E. coli" will consume glucose before lactose. Catabolite repression has also been observed in "E. coli" in the presence of other non-glucose sugars, such as arabinose and xylose, sorbitol, rhamnose, and ribose. In "E. coli", glucose catabolite repression is regulated by the phosphotransferase system, a multi-protein phosphorylation cascade that couples glucose uptake and metabolism.


title: Escherichia coli

text: Optimum growth of "E. coli" occurs at , but some laboratory strains can multiply at temperatures up to . "E. coli" grows in a variety of defined laboratory media, such as lysogeny broth, or any medium that contains glucose, ammonium phosphate monobasic, sodium chloride, magnesium sulfate, potassium phosphate dibasic, and water. Growth can be driven by aerobic or anaerobic respiration, using a large variety of redox pairs, including the oxidation of pyruvic acid, formic acid, hydrogen, and amino acids, and the reduction of substrates such as oxygen, nitrate, fumarate, dimethyl sulfoxide, and trimethylamine N-oxide. "E. coli" is classified as a facultative anaerobe. It uses oxygen when it is present and available. It can, however, continue to grow in the absence of oxygen using fermentation or anaerobic respiration. Respiraton type is managed in part by the arc system. The ability to continue growing in the absence of oxygen is an advantage to bacteria because their survival is increased in environments where water predominates.


title: Escherichia coli

text: The bacterial cell cycle is divided into three stages. The B period occurs between the completion of cell division and the beginning of DNA replication. The C period encompasses the time it takes to replicate the chromosomal DNA. The D period refers to the stage between the conclusion of DNA replication and the end of cell division. The doubling rate of "E. coli" is higher when more nutrients are available. However, the length of the C and D periods do not change, even when the doubling time becomes less than the sum of the C and D periods. At the fastest growth rates, replication begins before the previous round of replication has completed, resulting in multiple replication forks along the DNA and overlapping cell cycles.


title: Escherichia coli

text: The number of replication forks in fast growing "E. coli" typically follows 2n (n = 1, 2 or 3). This only happens if replication is initiated simultaneously from all origins of replications, and is referred to as synchronous replication. However, not all cells in a culture replicate synchronously. In this case cells do not have multiples of two replication forks. Replication initiation is then referred to being asynchronous. However, asynchrony can be caused by mutations to for instance DnaA or DnaA initiator-associating protein DiaA.


title: Escherichia coli

text: "E. coli" and related bacteria possess the ability to transfer DNA via bacterial conjugation or transduction, which allows genetic material to spread horizontally through an existing population. The process of transduction, which uses the bacterial virus called a bacteriophage, is where the spread of the gene encoding for the Shiga toxin from the "Shigella" bacteria to "E. coli" helped produce , the Shiga toxin-producing strain of "E. coli."


title: Escherichia coli

text: "E. coli" encompasses an enormous population of bacteria that exhibit a very high degree of both genetic and phenotypic diversity. Genome sequencing of many isolates of "E. coli" and related bacteria shows that a taxonomic reclassification would be desirable. However, this has not been done, largely due to its medical importance, and "E. coli" remains one of the most diverse bacterial species: only 20% of the genes in a typical "E. coli" genome is shared among all strains.


title: Escherichia coli

text: In fact, from the more constructive point of view, the members of genus "Shigella" ("S. dysenteriae", "S. flexneri", "S. boydii", and "S. sonnei") should be classified as "E. coli" strains, a phenomenon termed taxa in disguise. Similarly, other strains of "E. coli" (e.g. the K-12 strain commonly used in recombinant DNA work) are sufficiently different that they would merit reclassification.


title: Escherichia coli

text: A strain is a subgroup within the species that has unique characteristics that distinguish it from other strains. These differences are often detectable only at the molecular level; however, they may result in changes to the physiology or lifecycle of the bacterium. For example, a strain may gain pathogenic capacity, the ability to use a unique carbon source, the ability to take upon a particular ecological niche, or the ability to resist antimicrobial agents. Different strains of "E. coli" are often host-specific, making it possible to determine the source of fecal contamination in environmental samples. For example, knowing which "E. coli" strains are present in a water sample allows researchers to make assumptions about whether the contamination originated from a human, another mammal, or a bird.


title: Escherichia coli

text: A common subdivision system of "E. coli", but not based on evolutionary relatedness, is by serotype, which is based on major surface antigens (O antigen: part of lipopolysaccharide layer; H: flagellin; K antigen: capsule), e.g. O157:H7). It is, however, common to cite only the serogroup, i.e. the O-antigen. At present, about 190 serogroups are known. The common laboratory strain has a mutation that prevents the formation of an O-antigen and is thus not typeable.


title: Escherichia coli

text: Like all lifeforms, new strains of "E. coli" evolve through the natural biological processes of mutation, gene duplication, and horizontal gene transfer; in particular, 18% of the genome of the laboratory strain MG1655 was horizontally acquired since the divergence from "Salmonella". "E. coli" K-12 and "E. coli" B strains are the most frequently used varieties for laboratory purposes. Some strains develop traits that can be harmful to a host animal. These virulent strains typically cause a bout of diarrhea that is often self-limiting in healthy adults but is frequently lethal to children in the developing world. More virulent strains, such as , cause serious illness or death in the elderly, the very young, or the immunocompromised.


title: Escherichia coli

text: The genera "Escherichia" and "Salmonella" diverged around 102 million years ago (credibility interval: 57–176 mya), an event unrelated to the much earlier (see "Synapsid") divergence of their hosts: the former being found in mammals and the latter in birds and reptiles. This was followed by a split of an "Escherichia" ancestor into five species ("E. albertii", "E. coli", "E. fergusonii", "E. hermannii", and "E. vulneris"). The last "E. coli" ancestor split between 20 and 30 million years ago.


title: Escherichia coli

text: The long-term evolution experiments using "E. coli", begun by Richard Lenski in 1988, have allowed direct observation of genome evolution over more than 65,000 generations in the laboratory. For instance, "E. coli" typically do not have the ability to grow aerobically with citrate as a carbon source, which is used as a diagnostic criterion with which to differentiate "E. coli" from other, closely, related bacteria such as "Salmonella". In this experiment, one population of "E. coli" unexpectedly evolved the ability to aerobically metabolize citrate, a major evolutionary shift with some hallmarks of microbial speciation.


title: Escherichia coli

text: In the microbial world, a relationship of predation can be established similar to that observed in the animal world. Considered, it has been seen that "E. coli" is the prey of multiple generalist predators, such as "Myxococcus xanthus". In this predator-prey relationship, a parallel evolution of both species is observed through genomic and phenotypic modifications, in the case of "E. coli" the modifications are modified in two aspects involved in their virulence such as mucoid production (excessive production of exoplasmic acid alginate ) and the suppression of the OmpT gene, producing in future generations a better adaptation of one of the species that is counteracted by the evolution of the other, following a co-evolutionary model demonstrated by the Red Queen hypothesis.


title: Escherichia coli

text: "E. coli" is the type species of the genus ("Escherichia") and in turn "Escherichia" is the type genus of the family Enterobacteriaceae, where the family name does not stem from the genus "Enterobacter" + "i" (sic.) + "aceae", but from "enterobacterium" + "aceae" (enterobacterium being not a genus, but an alternative trivial name to enteric bacterium).


title: Escherichia coli

text: The original strain described by Escherich is believed to be lost, consequently a new type strain (neotype) was chosen as a representative: the neotype strain is U5/41,<ref name="doi:10.1186/1944-3277-9-2"></ref> also known under the deposit names DSM 30083, ATCC 11775, and NCTC 9001, which is pathogenic to chickens and has an O1:K1:H7 serotype. However, in most studies, either O157:H7, K-12 MG1655, or K-12 W3110 were used as a representative "E. coli". The genome of the type strain has only lately been sequenced.


title: Escherichia coli

text: Many strains belonging to this species have been isolated and characterised. In addition to serotype ("vide supra"), they can be classified according to their phylogeny, i.e. the inferred evolutionary history, as shown below where the species is divided into six groups. Particularly the use of whole genome sequences yields highly supported phylogenies. Based on such data, five subspecies of "E. coli" were distinguished.


title: Escherichia coli

text: The link between phylogenetic distance ("relatedness") and pathology is small, "e.g." the O157:H7 serotype strains, which form a clade ("an exclusive group")—group E below—are all enterohaemorragic strains (EHEC), but not all EHEC strains are closely related. In fact, four different species of "Shigella" are nested among "E. coli" strains ("vide supra"), while "E. albertii" and "E. fergusonii" are outside this group.


title: Escherichia coli

text: Indeed, all "Shigella" species were placed within a single subspecies of "E. coli" in a phylogenomic study that included the type strain, and for this reason an according reclassification is difficult.


title: Escherichia coli

text: All commonly used research strains of "E. coli" belong to group A and are derived mainly from Clifton's K-12 strain (λ F; O16) and to a lesser degree from d'Herelle's "Bacillus coli" strain (B strain) (O7).


title: Escherichia coli

text: The first complete DNA sequence of an "E. coli" genome (laboratory strain K-12 derivative MG1655) was published in 1997. It is a circular DNA molecule 4.6 million base pairs in length, containing 4288 annotated protein-coding genes (organized into 2584 operons), seven ribosomal RNA (rRNA) operons, and 86 transfer RNA (tRNA) genes. Despite having been the subject of intensive genetic analysis for about 40 years, many of these genes were previously unknown. The coding density was found to be very high, with a mean distance between genes of only 118 base pairs. The genome was observed to contain a significant number of transposable genetic elements, repeat elements, cryptic prophages, and bacteriophage remnants.


title: Escherichia coli

text: More than three hundred complete genomic sequences of "Escherichia" and "Shigella" species are known. The genome sequence of the type strain of "E. coli" was added to this collection before 2014. Comparison of these sequences shows a remarkable amount of diversity; only about 20% of each genome represents sequences present in every one of the isolates, while around 80% of each genome can vary among isolates. Each individual genome contains between 4,000 and 5,500 genes, but the total number of different genes among all of the sequenced "E. coli" strains (the pangenome) exceeds 16,000. This very large variety of component genes has been interpreted to mean that two-thirds of the "E. coli" pangenome originated in other species and arrived through the process of horizontal gene transfer.


title: Escherichia coli

text: Genes in "E. coli" are usually named in accordance with the uniform nomenclature proposed by Demerec et al. Gene names are 3-letter acronyms that derive from their function (when known) or mutant phenotype and are italicized. When multiple genes have the same acronym, the different genes are designated by a capital later that follows the acronym and is also italicized. For instance, "recA" is named after its role in homologous recombination plus the letter A. Functionally related genes are named "recB", "recC", "recD" etc. The proteins are named by uppercase acronyms, e.g. RecA, RecB, etc. When the genome of "E. coli" strain K-12 substr. MG1655 was sequenced, all known or predicted protein-coding genes were numbered (more or less) in their order on the genome and abbreviated by b numbers, such as b2819 (= "recD"). The "b" names were created after Fred Blattner, who led the genome sequence effort. Another numbering system was introduced with the sequence of another "E. coli" K-12 substrain, W3110, which was sequenced in Japan and hence uses numbers starting by JW... (Japanese W3110), e.g. JW2787 (= "recD"). Hence, "recD" = b2819 = JW2787. Note, however, that most databases have their own numbering system, e.g. the EcoGene database uses EG10826 for "recD". Finally, ECK numbers are specifically used for alleles in the MG1655 strain of "E. coli" K-12. Complete lists of genes and their synonyms can be obtained from databases such as EcoGene or Uniprot.


title: Escherichia coli

text: The genome sequence of "E. coli" predicts 4288 protein-coding genes, of which 38 percent initially had no attributed function. Comparison with five other sequenced microbes reveals ubiquitous as well as narrowly distributed gene families; many families of similar genes within "E. coli" are also evident. The largest family of paralogous proteins contains 80 ABC transporters. The genome as a whole is strikingly organized with respect to the local direction of replication; guanines, oligonucleotides possibly related to replication and recombination, and most genes are so oriented. The genome also contains insertion sequence (IS) elements, phage remnants, and many other patches of unusual composition indicating genome plasticity through horizontal transfer.


title: Escherichia coli

text: Several studies have experimentally investigated the proteome of "E. coli". By 2006, 1,627 (38%) of the predicted proteins (open reading frames, ORFs) had been identified experimentally. Mateus et al. 2020 detected 2,586 proteins with at least 2 peptides (60% of all proteins).


title: Escherichia coli

text: Although much fewer bacterial proteins seem to have post-translational modifications (PTMs) compared to eukaryotic proteins, a substantial number of proteins are modified in "E. coli". For instance, Potel et al. (2018) found 227 phosphoproteins of which 173 were phosphorylated on histidine. Interestingly, the majority of phosphorylated amino acids were serine (1,220 sites) with only 246 sites on histidine and 501 phosphorylated theronines and 162 tyrosines.


title: Escherichia coli

text: The interactome of "E. coli" has been studied by affinity purification and mass spectrometry (AP/MS) and by analyzing the binary interactions among its proteins.


title: Escherichia coli

text: Protein complexes. A 2006 study purified 4,339 proteins from cultures of strain K-12 and found interacting partners for 2,667 proteins, many of which had unknown functions at the time. A 2009 study found 5,993 interactions between proteins of the same "E. coli" strain, though these data showed little overlap with those of the 2006 publication.


title: Escherichia coli

text: Binary interactions. Rajagopala "et al." (2014) have carried out systematic yeast two-hybrid screens with most "E. coli" proteins, and found a total of 2,234 protein-protein interactions. This study also integrated genetic interactions and protein structures and mapped 458 interactions within 227 protein complexes.


title: Escherichia coli

text: "E. coli" belongs to a group of bacteria informally known as coliforms that are found in the gastrointestinal tract of warm-blooded animals. "E. coli" normally colonizes an infant's gastrointestinal tract within 40 hours of birth, arriving with food or water or from the individuals handling the child. In the bowel, "E. coli" adheres to the mucus of the large intestine. It is the primary facultative anaerobe of the human gastrointestinal tract. (Facultative anaerobes are organisms that can grow in either the presence or absence of oxygen.) As long as these bacteria do not acquire genetic elements encoding for virulence factors, they remain benign commensals.


title: Escherichia coli

text: Due to the low cost and speed with which it can be grown and modified in laboratory settings, "E. coli" is a popular expression platform for the production of recombinant proteins used in therapeutics. One advantage to using "E. coli" over another expression platform is that "E. coli" naturally does not export many proteins into the periplasm, making it easier to recover a protein of interest without cross-contamination. The "E. coli" K-12 strains and their derivatives (DH1, DH5α, MG1655, RV308 and W3110) are the strains most widely used by the biotechnology industry. Nonpathogenic "E. coli" strain Nissle 1917 (EcN), (Mutaflor) and "E. coli" O83:K24:H31 (Colinfant)) are used as probiotic agents in medicine, mainly for the treatment of various gastrointestinal diseases, including inflammatory bowel disease. It is thought that the EcN strain might impede the growth of opportunistic pathogens, including "Salmonella" and other coliform enteropathogens, through the production of microcin proteins the production of siderophores.


title: Escherichia coli

text: Most "E. coli" strains do not cause disease, naturally living in the gut, but virulent strains can cause gastroenteritis, urinary tract infections, neonatal meningitis, hemorrhagic colitis, and Crohn's disease. Common signs and symptoms include severe abdominal cramps, diarrhea, hemorrhagic colitis, vomiting, and sometimes fever. In rarer cases, virulent strains are also responsible for bowel necrosis (tissue death) and perforation without progressing to hemolytic-uremic syndrome, peritonitis, mastitis, sepsis, and Gram-negative pneumonia. Very young children are more susceptible to develop severe illness, such as hemolytic uremic syndrome; however, healthy individuals of all ages are at risk to the severe consequences that may arise as a result of being infected with "E. coli".


title: Escherichia coli

text: Some strains of "E. coli", for example O157:H7, can produce Shiga toxin (classified as a bioterrorism agent). The Shiga toxin causes inflammatory responses in target cells of the gut, leaving behind lesions which result in the bloody diarrhea that is a symptom of a Shiga toxin-producing "E. coli" (STEC) infection. This toxin further causes premature destruction of the red blood cells, which then clog the body's filtering system, the kidneys, in some rare cases (usually in children and the elderly) causing hemolytic-uremic syndrome (HUS), which may lead to kidney failure and even death. Signs of hemolytic uremic syndrome include decreased frequency of urination, lethargy, and paleness of cheeks and inside the lower eyelids. In 25% of HUS patients, complications of nervous system occur, which in turn causes strokes. In addition, this strain causes the buildup of fluid (since the kidneys do not work), leading to edema around the lungs, legs, and arms. This increase in fluid buildup especially around the lungs impedes the functioning of the heart, causing an increase in blood pressure.


title: Escherichia coli

text: Uropathogenic "E. coli" (UPEC) is one of the main causes of urinary tract infections. It is part of the normal microbiota in the gut and can be introduced in many ways. In particular for females, the direction of wiping after defecation (wiping back to front) can lead to fecal contamination of the urogenital orifices. Anal intercourse can also introduce this bacterium into the male urethra, and in switching from anal to vaginal intercourse, the male can also introduce UPEC to the female urogenital system.


title: Escherichia coli

text: Enterotoxigenic "E. coli" (ETEC) is the most common cause of traveler's diarrhea, with as many as 840 million cases worldwide in developing countries each year. The bacteria, typically transmitted through contaminated food or drinking water, adheres to the intestinal lining, where it secretes either of two types of enterotoxins, leading to watery diarrhea. The rate and severity of infections are higher among children under the age of five, including as many as 380,000 deaths annually.


title: Escherichia coli

text: In May 2011, one "E. coli" strain, , was the subject of a that began in Germany. Certain strains of "E. coli" are a major cause of foodborne illness. The outbreak started when several people in Germany were infected with enterohemorrhagic "E. coli" (EHEC) bacteria, leading to hemolytic-uremic syndrome (HUS), a medical emergency that requires urgent treatment. The outbreak did not only concern Germany, but also 15 other countries, including regions in North America. On 30 June 2011, the German "Bundesinstitut für Risikobewertung (BfR)" (Federal Institute for Risk Assessment, a federal institute within the German Federal Ministry of Food, Agriculture and Consumer Protection) announced that seeds of fenugreek from Egypt were likely the cause of the EHEC outbreak.


title: Escherichia coli

text: Some studies have demonstrated an absence of E. "coli" in the gut flora of subjects with the metabolic disorder Phenylketonuria. It is hypothesized that the absence of these normal bacterium impairs the production of the key vitamins B (riboflavin) and K (menaquinone) - vitamins which are implicated in many physiological roles in humans such as cellular and bone metabolism - and so contributes to the disorder.


title: Escherichia coli

text: Carbapenem-resistant "E. coli" (carbapenemase-producing "E. coli") that are resistant to the carbapenem class of antibiotics, considered the drugs of last resort for such infections. They are resistant because they produce an enzyme called a carbapenemase that disables the drug molecule.


title: Escherichia coli

text: The time between ingesting the STEC bacteria and feeling sick is called the "incubation period". The incubation period is usually 3–4 days after the exposure, but may be as short as 1 day or as long as 10 days. The symptoms often begin slowly with mild belly pain or non-bloody diarrhea that worsens over several days. HUS, if it occurs, develops an average 7 days after the first symptoms, when the diarrhea is improving.


title: Escherichia coli

text: Diagnosis of infectious diarrhea and identification of antimicrobial resistance is performed using a stool culture with subsequent antibiotic sensitivity testing. It requires a minimum of 2 days and maximum of several weeks to culture gastrointestinal pathogens. The sensitivity (true positive) and specificity (true negative) rates for stool culture vary by pathogen, although a number of human pathogens can not be cultured. For culture-positive samples, antimicrobial resistance testing takes an additional 12–24 hours to perform.


title: Escherichia coli

text: Current point of care molecular diagnostic tests can identify "E. coli" and antimicrobial resistance in the identified strains much faster than culture and sensitivity testing. Microarray-based platforms can identify specific pathogenic strains of "E. coli" and "E. coli"-specific AMR genes in two hours or less with high sensitivity and specificity, but the size of the test panel (i.e., total pathogens and antimicrobial resistance genes) is limited. Newer metagenomics-based infectious disease diagnostic platforms are currently being developed to overcome the various limitations of culture and all currently available molecular diagnostic technologies.


title: Escherichia coli

text: The mainstay of treatment is the assessment of dehydration and replacement of fluid and electrolytes. Administration of antibiotics has been shown to shorten the course of illness and duration of excretion of enterotoxigenic "E. coli" (ETEC) in adults in endemic areas and in traveller's diarrhea, though the rate of resistance to commonly used antibiotics is increasing and they are generally not recommended. The antibiotic used depends upon susceptibility patterns in the particular geographical region. Currently, the antibiotics of choice are fluoroquinolones or azithromycin, with an emerging role for rifaximin. Oral rifaximin, a semisynthetic rifamycin derivative, is an effective and well-tolerated antibacterial for the management of adults with non-invasive traveller's diarrhea. Rifaximin was significantly more effective than placebo and no less effective than ciprofloxacin in reducing the duration of diarrhea. While rifaximin is effective in patients with "E. coli"-predominant traveller's diarrhea, it appears ineffective in patients infected with inflammatory or invasive enteropathogens.


title: Escherichia coli

text: ETEC is the type of "E. coli" that most vaccine development efforts are focused on. Antibodies against the LT and major CFs of ETEC provide protection against LT-producing, ETEC-expressing homologous CFs. Oral inactivated vaccines consisting of toxin antigen and whole cells, i.e. the licensed recombinant cholera B subunit (rCTB)-WC cholera vaccine Dukoral, have been developed. There are currently no licensed vaccines for ETEC, though several are in various stages of development. In different trials, the rCTB-WC cholera vaccine provided high (85–100%) short-term protection. An oral ETEC vaccine candidate consisting of rCTB and formalin inactivated "E. coli" bacteria expressing major CFs has been shown in clinical trials to be safe, immunogenic, and effective against severe diarrhoea in American travelers but not against ETEC diarrhoea in young children in Egypt. A modified ETEC vaccine consisting of recombinant "E. coli" strains over-expressing the major CFs and a more LT-like hybrid toxoid called LCTBA, are undergoing clinical testing.


title: Escherichia coli

text: Other proven prevention methods for "E. coli" transmission include handwashing and improved sanitation and drinking water, as transmission occurs through fecal contamination of food and water supplies. Additionally, thoroughly cooking meat and avoiding consumption of raw, unpasteurized beverages, such as juices and milk are other proven methods for preventing "E. coli". Lastly, cross-contamination of utensils and work spaces should be avoided when preparing food.


title: Escherichia coli

text: Because of its long history of laboratory culture and ease of manipulation, "E. coli" plays an important role in modern biological engineering and industrial microbiology. The work of Stanley Norman Cohen and Herbert Boyer in "E. coli", using plasmids and restriction enzymes to create recombinant DNA, became a foundation of biotechnology.


title: Escherichia coli

text: "E. coli" is a very versatile host for the production of heterologous proteins, and various protein expression systems have been developed which allow the production of recombinant proteins in "E. coli". Researchers can introduce genes into the microbes using plasmids which permit high level expression of protein, and such protein may be mass-produced in industrial fermentation processes. One of the first useful applications of recombinant DNA technology was the manipulation of "E. coli" to produce human insulin.


title: Escherichia coli

text: Many proteins previously thought difficult or impossible to be expressed in "E. coli" in folded form have been successfully expressed in "E. coli". For example, proteins with multiple disulphide bonds may be produced in the periplasmic space or in the cytoplasm of mutants rendered sufficiently oxidizing to allow disulphide-bonds to form, while proteins requiring post-translational modification such as glycosylation for stability or function have been expressed using the N-linked glycosylation system of "Campylobacter jejuni" engineered into "E. coli".


title: Escherichia coli

text: Modified "E. coli" cells have been used in vaccine development, bioremediation, production of biofuels, lighting, and production of immobilised enzymes.


title: Escherichia coli

text: Strain K-12 is a mutant form of "E. coli" that over-expresses the enzyme Alkaline Phosphatase (ALP). The mutation arises due to a defect in the gene that constantly codes for the enzyme. A gene that is producing a product without any inhibition is said to have constitutive activity. This particular mutant form is used to isolate and purify the aforementioned enzyme.


title: Escherichia coli

text: Strain JM109 is a mutant form of "E. coli" that is recA and endA deficient. The strain can be utilized for blue/white screening when the cells carry the fertility factor episome. Lack of recA decreases the possibility of unwanted restriction of the DNA of interest and lack of endA inhibit plasmid DNA decomposition. Thus, JM109 is useful for cloning and expression systems.


title: Escherichia coli

text: "E. coli" is frequently used as a model organism in microbiology studies. Cultivated strains (e.g. "E. coli" K12) are well-adapted to the laboratory environment, and, unlike wild-type strains, have lost their ability to thrive in the intestine. Many laboratory strains lose their ability to form biofilms. These features protect wild-type strains from antibodies and other chemical attacks, but require a large expenditure of energy and material resources. "E. coli" is often used as a representative microorganism in the research of novel water treatment and sterilisation methods, including photocatalysis. By standard plate count methods, following sequential dilutions, and growth on agar gel plates, the concentration of viable organisms or CFUs (Colony Forming Units), in a known volume of treated water can be evaluated, allowing the comparative assessment of materials performance.


title: Escherichia coli

text: In 1946, Joshua Lederberg and Edward Tatum first described the phenomenon known as bacterial conjugation using "E. coli" as a model bacterium, and it remains the primary model to study conjugation. "E. coli" was an integral part of the first experiments to understand phage genetics, and early researchers, such as Seymour Benzer, used "E. coli" and phage T4 to understand the topography of gene structure. Prior to Benzer's research, it was not known whether the gene was a linear structure, or if it had a branching pattern.


title: Escherichia coli

text: "E. coli" was one of the first organisms to have its genome sequenced; the complete genome of "E. coli" K12 was published by "Science" in 1997.


title: Escherichia coli

text: From 2002 to 2010, a team at the Hungarian Academy of Science created a strain of "Escherichia coli" called MDS42, which is now sold by Scarab Genomics of Madison, WI under the name of "Clean Genome "E. coli"", where 15% of the genome of the parental strain ("E. coli" K-12 MG1655) were removed to aid in molecular biology efficiency, removing IS elements, pseudogenes and phages, resulting in better maintenance of plasmid-encoded toxic genes, which are often inactivated by transposons. Biochemistry and replication machinery were not altered.


title: Escherichia coli

text: By evaluating the possible combination of nanotechnologies with landscape ecology, complex habitat landscapes can be generated with details at the nanoscale. On such synthetic ecosystems, evolutionary experiments with "E. coli" have been performed to study the spatial biophysics of adaptation in an island biogeography on-chip.


title: Escherichia coli

text: In other studies, non-pathogenic "E. coli" has been used as a model microorganism towards understanding the effects of simulated microgravity (on Earth) on the same.


title: Escherichia coli

text: Since 1961, scientists proposed the idea of genetic circuits used for computational tasks. Collaboration between biologists and computing scientists has allowed designing digital logic gates on the metabolism of "E. coli". As Lac operon is a two-stage process, genetic regulation in the bacteria is used to realize computing functions. The process is controlled at the transcription stage of DNA into messenger RNA.


title: Escherichia coli

text: Studies are being performed attempting to program "E. coli" to solve complicated mathematics problems, such as the Hamiltonian path problem.


title: Escherichia coli

text: A computer to control protein production of "E. coli" within yeast cells has been developed. A method has also been developed to use bacteria to behave as an LCD screen.


title: Escherichia coli

text: In July 2017, separate experiments with "E. coli" published on Nature showed the potential of using living cells for computing tasks and storing information. A team formed with collaborators of the Biodesign Institute at Arizona State University and Harvard’s Wyss Institute for Biologically Inspired Engineering developed a biological computer inside "E. coli" that responded to a dozen inputs. The team called the computer "ribocomputer", as it was composed of ribonucleic acid. Meanwhile, Harvard researchers probed that is possible to store information in bacteria after successfully archiving images and movies in the DNA of living "E. coli" cells. In 2021, a team led by biophysicist Sangram Bagh realized a study with "E. coli" to solve 2 × 2 maze problems to probe the principle for distributed computing among cells.


title: Escherichia coli

text: In 1885, the German-Austrian pediatrician Theodor Escherich discovered this organism in the feces of healthy individuals. He called it "Bacterium coli commune" because it is found in the colon. Early classifications of prokaryotes placed these in a handful of genera based on their shape and motility (at that time Ernst Haeckel's classification of bacteria in the kingdom Monera was in place).


title: Escherichia coli

text: "Bacterium coli" was the type species of the now invalid genus "Bacterium" when it was revealed that the former type species (""Bacterium triloculare"") was missing. Following a revision of "Bacterium", it was reclassified as "Bacillus coli" by Migula in 1895 and later reclassified in the newly created genus "Escherichia", named after its original discoverer, by Aldo Castellani and Albert John Chalmers.


title: Escherichia coli

text: In 1996, the world's worst to date outbreak of "E. coli" food poisoning occurred in Wishaw, Scotland, killing 21 people. This death toll was exceeded in 2011, when the , linked to organic fenugreek sprouts, killed 53 people.


title: Escherichia coli

text: "E. coli" has several practical uses besides its use as a vector for genetic experiments and processes. For example, "E. coli" can be used to generate synthetic propane and recombinant human growth hormone.


title: Mermaid

text: In folklore, a mermaid is an aquatic creature with the head and upper body of a female human and the tail of a fish. Mermaids appear in the folklore of many cultures worldwide, including Europe, Asia, and Africa.


title: Mermaid

text: Mermaids are sometimes associated with perilous events such as floods, storms, shipwrecks, and drownings. In other folk traditions (or sometimes within the same traditions), they can be benevolent or beneficent, bestowing boons or falling in love with humans.


title: Mermaid

text: The male equivalent of the mermaid is the merman, also a familiar figure in folklore and heraldry. Although traditions about and sightings of mermen are less common than those of mermaids, they are generally assumed to co-exist with their female counterparts. The male and the female collectively are sometimes referred to as merfolk or merpeople.


title: Mermaid

text: The Western concept of mermaids as beautiful, seductive singers may have been influenced by the Sirens of Greek mythology, which were originally half-birdlike, but came to be pictured as half-fishlike in the Christian era. Historical accounts of mermaids, such as those reported by Christopher Columbus during his exploration of the Caribbean, may have been sightings of manatees or similar aquatic mammals. While there is no evidence that mermaids exist outside folklore, reports of mermaid sightings continue to the present day.


title: Mermaid

text: Mermaids have been a popular subject of art and literature in recent centuries, such as in Hans Christian Andersen's literary fairy tale "The Little Mermaid" (1836). They have subsequently been depicted in operas, paintings, books, comics, animation, and live-action films.


title: Mermaid

text: The English word "mermaid" is not very old, with the earliest attestation in Middle English (Chaucer, "Nun's Priest's Tale", c. 1390). The compound word is formed from "'" (sea), and "".


title: Mermaid

text: Another English word "†mermin" ( in the OED) for 'siren or mermaid' is older, though now obsolete. It derives from Old English , ad. 'sea' + 'female slave', earliest attestation , as a gloss for "siren", in "Corpus Glossary" (c. 725).


title: Mermaid

text: Middle English example in a bestiary (c. 1220?; MS. now dated to 1275–1300) is indeed 'mermaid', part maiden, part fish-like.


title: Mermaid

text: The Middle High German cognate ', (mod. German ""), "mermaid", is attested in epics, and the one in "Rabenschlacht" is a great-grandmother; this same figure is in an Old Swedish text a ', and in Old Norse a ("siókona" [sic.]; "sea-woman").


title: Mermaid

text: Old Norse , masculine noun, is also listed as cognate to "†mermin", as well as ON , modern Icelandic , and modern Norwegian "marmæle".


title: Mermaid

text: Old English is another related term, and appears once in reference not so much to a mermaid but a certain sea hag, and not well-attested later.


title: Mermaid

text: Its MHG cognate , also defined as "" in modern German with perhaps "" a valid English definition. The word is attested, among other medieval epics, in the "Nibelungenlied", and rendered "merwoman", "mermaid", "water sprite", or other terms; the two in the story are translated as ON ("sea-women").


title: Mermaid

text: The siren of Ancient Greek mythology became conflated with mermaids during the medieval period. Some European Romance languages still use cognate terms for "siren" to denote the mermaid, e.g., French and Spanish and Italian "".


title: Mermaid

text: In the early Greek period, the sirens were conceived of as human-headed birds, but by the classical period, the Greeks sporadically depicted the siren as part fish in art.


title: Mermaid

text: The siren's part-fish appearance became increasingly popular during the Middle Ages. And the traits of the classical sirens, such as using their beautiful song as a lure as told by Homer, has often been transferred to mermaids.


title: Mermaid

text: These change of the medieval siren from bird to fish were thought by some to be the influence of Teutonic myth, later expounded in literary legends of Lorelei and Undine; though a dissenting comment is that parallels are not limited to Teutonic culture.


title: Mermaid

text: The earliest text describing the siren as fish-tailed occurs in the "Liber Monstrorum de diversis generibus" (7th–mid 8th cent.), which described sirens as "sea girls" () whose beauty in form and sweet song allure seafarers, but beneath the human head and torso, have the scaly tail-end of a fish with which they can navigate the sea.


title: Mermaid

text: "Sirens are mermaids" (Old High German/Early ) is explicit in the aforementioned Old German "Physiologus" (11th century).


title: Mermaid

text: The Middle English bestiary (mid-13th century) clearly means "mermaid" when it explains the siren to be a "mereman", stating that she has a body and breast like that of a maiden but joined, at the navel, by a body part which is definitely fish, with fins growing out of her.


title: Mermaid

text: Old French verse bestiaries (e.g. Philipp de Thaun's version, written c. 1121–1139) also accommodated by stating that a part of the siren may be bird or fish.


title: Mermaid

text: In a 9th century "Physiologus" manufactured in France (Fig., top left), the siren was illustrated as a "woman-fish", i.e., mermaid-like, despite being described as bird-like in the text.


title: Mermaid

text: The Bodleian bestiary dated 1220–12 also pictures a group of fish-tailed mermaid-like sirens (Fig. bottom), contradicting its text which likens it to a winged fowl () down to their feet.


title: Mermaid

text: In the interim, the siren as pure mermaid was becoming commonplace, particularly in the so-called "Second Family" Latin bestiaries, as represented in one of the early manuscripts classified into this group (Additional manuscript 11283, c. 1170–1180s. Fig., top right).


title: Mermaid

text: While the siren holding a fish was a commonplace theme, the siren in bestiaries were also sometimes depicted holding the comb, or the mirror.


title: Mermaid

text: In the Christian moralizing context (e.g the bestiaries), the mermaid's mirror and comb were held as the symbol of vanity.


title: Mermaid

text: The sea-monsters Scylla and Charybdis, who lived near the sirens, were also female and had some fishlike attributes. Though Scylla's violence is contrasted with the sirens' seductive ways by certain classical writers, Scylla and Charybdis lived near the sirens' domain. In Etruscan civilization before the 6th century BC, Scylla was portrayed as a mermaid-like creature with two tails. Some have argued that the two-tailed Melusine of later European art is traceable to this Etruscan Scylla. A sporadic example of sirens as mermaids (tritonesses) in Early Greek art (3rd century BC), can be explained as the contamination of the siren myth with Scylla and Charybdis.


title: Mermaid

text: The female oceanids, nereids and naiads are mythical water nymphs or deities, although not depicted with fish tails. "Nereid" and "nymph" have also been applied to actual mermaid-like marine creatures purported to exist, from Pliny (cf. §Roman Lusitania and Gaul) and onwards. Jane Ellen Harrison (1882) has speculated that the mermaids or tritonesses of Greek and Roman mythology may have been brought from the Middle East, possibly transmitted by Phoenician mariners.


title: Mermaid

text: The Greek god Triton had two fish tails instead of legs, and later became pluralized as a group. The prophetic sea deity Glaucus was also depicted with a fish tail and sometimes with fins for arms.


title: Mermaid

text: Depictions of entities with the upper bodies of humans and the tails of fish appear in Mesopotamian artwork from the Old Babylonian Period onwards, on cylinder seals. These figures are usually mermen ("kulullû"), but mermaids do occasionally appear. The name for the mermaid figure may have been "*kuliltu", meaning "fish-woman". Such figures were used in Neo-Assyrian art as protective figures and were shown in both monumental sculpture and in small, protective figurines.


title: Mermaid

text: A mermaid-like goddess, identified by Greek and Roman writers as Derceto or Atargatis, was worshipped at Ashkelon. In a myth recounted by Diodorus in the 1st century BCE, Derceto gave birth to a child from an affair. Ashamed, she abandoned the child in the desert and drowned herself in a lake, only to be transformed into a human-headed fish. The child, Semiramis, was fed by doves and survived to become a queen.


title: Mermaid

text: In the 2nd century AD, Lucian described seeing a Phoenician statue of Derceto with the upper body of a woman and the tail of a fish. He noted the contrast with the grand statue located at her Holy City (Hierapolis Bambyce), which appeared entirely human.


title: Mermaid

text: In the myth, Semiramis's first husband is named Onnes. Some scholars have compared this to the earlier Mesopotamian myth of Oannes, one of the "apkallu" or seven sages described as fish-men in cuneiform texts. While Oannes was a servant of the water deity Ea, having gained wisdom from the god, English writer Arthur Waugh understood Oannes to be equivalent to Ea, and proposed that surely "Oannes had a fish-tailed wife" and descendants, with Atargatis being one deity thus descended, "through the mists of time".


title: Mermaid

text: Diodorus's chronology of Queen Semiramis resembles the feats of Alexander the Great (campaigns to India, etc.), and Diodorus may have woven the Macedonian king's material via some unnamed source. There is a mermaid legend attached to Alexander the Great's sister, but this is of post-medieval vintage (see below).


title: Mermaid

text: Sometime before 546 BC, Milesian philosopher Anaximander postulated that mankind had sprung from an aquatic animal species, a theory that is sometimes called the Aquatic Ape Theory. He thought that humans, who begin life with prolonged infancy, could not have survived otherwise.


title: Mermaid

text: There are also naturalist theories on the origins of the mermaid, postulating they derive from sightings of manatees, dugongs or even seals.


title: Mermaid

text: Still another theory, tangentially related to the aforementioned Aquatic Ape Theory, is that the mermaids of folklore were actually human women who trained over time to be skilled divers for things like sponges, and spent a lot of time in the sea as a result. One proponent of this theory is British author William Bond, who has written several books about it.


title: Mermaid

text: Two prophetic merwomen (MHG pl.: ), Sigelinde (MHG: Sigelint) and her maternal aunt Hadeburg (MHG: Hadeburc) are bathing in the Danube River when Hagen von Tronje encounters them ("Nibelungenlied", Âventiure 25).


title: Mermaid

text: They are called "sjókonar" ("sea woman") in the Old Norse "Þiđreks saga". There is a swan maiden tale motif involved here (Hagen robs their clothing), but Grimm thought they must have actually been swan maidens, since they are described as hovering above water.


title: Mermaid

text: In any case, this brief segment became the "foundational" groundwork of subsequent water-nix lore and literature that developed in the Germanic sphere.


title: Mermaid

text: They are a probable source of the three Rhine maidens in Richard Wagner's opera "Das Rheingold". Though conceived of as swan-maidens in Wagner's 1848 scenario, the number being a threesome was suggested by the woodcut by Julius Schnorr von Carolsfeld and Eugen Napoleon Neureuther in the Pfizer edition of 1843 (fig. on the left).


title: Mermaid

text: Middle High German "mereminne" 'mermaid' is mentioned, among other epics, in the "Rabenschlacht" ("Battle of Ravenna", 13th cent.) of the Dietrich cycle. The mermaid (or ) is named Wâchilt and is the ancestress of the traitorous Wittich who carries him off at the time of peril to her "submarine home".


title: Mermaid

text: This material has been found translated as a medieval "Þiðreks saga" only in a late, reworked Swedish version, i.e., one of the closing chapters of "Ðiðriks saga" (15th century, also known as the "Swedish epilogue".). The mermaid/undine is here translated as Old Swedish .


title: Mermaid

text: The genealogy is given in the saga: the sea-woman and Villcinus (Vilkinus), king of Scandinavia together had a son, Vaði (Wade) of (Sjóland=Sjælland, Zealand) who was a giant (); whose son was Velent (Wayland the Smith), whose son after that was Viðga Velentsson (Wittich or Witige), who became a companion/champion of King Þiðrekr (Dietrich von Bern).


title: Mermaid

text: The frequently mentioned Sjælland, Denmark is interpreted to the divided portion of Villcina-land inherited by the bastard prince Vaði/Wade. The Swedish epilogue transposed the location of the crucial battle where the mermaid appeared, from Ravenna, Northern Italy (supposedly, in the original German epic "Rabenschlacht"), to Gronsport, somewhere on the Moselle, in Northern Germany, then transported Viðga back to Sjælland.


title: Mermaid

text: The Norman chapel in Durham Castle, built around 1078, has what is probably the earliest surviving artistic depiction of a mermaid in England. It can be seen on a south-facing capital above one of the original Norman stone pillars.


title: Mermaid

text: Mermaids appear in British folklore as unlucky omens, both foretelling disaster and provoking it. Several variants of the ballad "Sir Patrick Spens" depict a mermaid speaking to the doomed ships. In some versions, she tells them they will never see land again; in others, she claims they are near shore, which they are wise enough to know means the same thing. Mermaids can also be a sign of approaching rough weather, and some have been described as monstrous in size, up to .]


title: Mermaid

text: In another short ballad, "Clerk Colvill" (Child ballad No. 42), the mermaid seduces the title character and foretells his doom. It has been surmised that in the original complete version, the man was being penalized for spurning her, though the Scandinavian counterparts that tells the complete story feature an elf-woman or elf queen rather than mermaid.