Cross-reactivity and antigenic structure of the C 5 component of human complement
W e tr ied to f ind some corre la t ion be tween t he syn thes i s of p roazu lenes in t he essent ia l oil of s o m e species oi the genus Achilles and t he n u m b e r of c h r o m o s o m e s in thei r somat ic cells: 12 species were i nves t i ga t ed ; in each case, samples of wild and cu l t iva t ed p l an t s of local and foreign origin were inc luded (table). P roazu lenes were ident i f ied in a wa te r ex t r ac t ob ta ined f rom t he herbage, us ing t he m e t h o d of S tah l based on color reac t ion of azulenes wi th p d i m e t h y l a m i n o benza ldehyde [6]. The n u m b e r of ch romosomes in mi to t ic ceils in vege t a t i on or roots af ter ge rmi na t i on was de t e rmined b y t he m e t h o d ol E h r e n d o r f e r [7]. The e x p e r i m e n t s showed t h a t the genus Achilles is polyploid wi th the base n u m b e r x = 9 of ch romosomes . P roazu lenes were p r e sen t in all s amples of the species Achilles coZlina Becke t and Achilles pannonica Scheele; t he former is t e t r a ploid (2ar 36), t he la t t e r hexa or octoploid ( 2 n = 54 or 2n = 72; table). O the r species (except Achilles miile]oIium L.
An immunological time scale for primate evolution consistent with fossil evidence
SummaryAn immunological time scale of primate, evolution is derived, which is based on the comparison of determinant structure — colinear to the corresponding structural genes —of homologous plasma proteins. The ages calculated for the last common ancestors (LCA) of man and pongids, cercopithecoids, platyrrhinians, (cebus) and prosimians are 13.9, 28.3, 54.9, and 63.3 million years respectively, with the LCA of all eutherians assumedto be 70 million years old. The result and the concept employed are discussed.ZusammenfassungEs wird eine immunologische Zeitskala der Primatenevolution abgeleitet, die auf einem Vergleich der Determinantenstrukturen — die colinear mit den entsprechenden DNS-Basensequenzen sind — von homologen Plasmaeiweißen, beruht. Die Alter der letzten gemeinsamen Vorfahren (LGV) von Mensch und Pongiden Ceropithecoiden, Platyrrhiniern (Cebus) und Prosimiern wurden mit 13,9, 28,3 54,9 und 63,3 Millionen Jahren ermittelt. Die Zahlen beruhen auf der Annahme, daß der LGV aller Eutheria 70 Millionen Jahre alt ist. Dieses Ergebnis und unser theoretisches Konzept werden näher erörtert.
The peculiar thermo-structural behavior of the anionic lipid DMPG.
Aqueous dispersions of the anionic phospholipid dimyristoyl phosphatidylglycerol (DMPG), around 100 mM ionic strength, are known to exhibit a thermal behavior similar to that of the largely studied lipid dimyristoyl phosphatidylcholine (DMPC), which undergoes a gel to liquid crystalline phase transition at 23 degrees C, well characterized by differential scanning calorimetry (DSC), and other methods. However, at low ionic strength, DMPG has been shown to present a large gel-fluid transition region, ranging from 18 to 35 degrees C. This intermediate phase is optically transparent and characterized by a continuous change in membrane packing. Structural properties of the DMPG gel-fluid transition region will be discussed, based on results obtained by several techniques: electron spin resonance (ESR) of spin labels at the membrane surface and intercalated at different depths in the bilayer; light scattering; DSC; small angle X-ray scattering (SAXS); and fluorescence spectroscopy of probes in the bilayer.