Dry mass of Fusarium roseum spores before and after germination
The total dry mass of Fusarium roseum spores and contained lipid bodies were determined before and after spores germinated using quantitative interference microscopy. The mean for spore dry mass before germination was about 57 pg. Lipid bodies accounted for about 61% of that. Areas of lipid bodies in spores before and after germination were about 23 % but the contents of the lipid bodies accounted for only 10% of the spore dry mass after germination. The total dry mass of the spore and germ tube(s) greatly exceeded that of the spore before germination. We infer that nutrients for germ tube growth are derived from within the germinating spore and from the medium which must contain nutrients leached from non-germinating spores.
Image-Charge Detection - Novel Instrumentation and Applications
Image-Charge Detection – Novel Instrumentation and Applications Brandon Lee Barney Department of Chemistry and Biochemistry, BYU Doctor of Philosophy Image-charge detection is an analytical technique in which a highly-charged particle is detected by the magnitude of the image current that it generates in a detecting electrode. This current is represented as a voltage between the charged particle and the sensing electrode. It is a single particle detection method, ideal for the analysis of large, variable mass particles such as biological cells. Some of the physical properties of Bacillus subtilis spores were explored using different applications of image-charge detection. B. subtilis is a gram-negative spore-forming bacteria that has been shown to exhibit extremophile behavior. The particular extremophile behavior that was investigated in this study is the resistance to extreme mechanical stress. The effects of high-velocity impacts upon these spores were studied using image-charge detection. The elastic properties of these spores as well as spore survivability to high-velocity impacts were investigated. Spores were shown to survive impacts at velocities up to 299 ± 28 m/s. The average kinetic energy loss experienced by impacting spores, regardless of velocity at impact, was between 71 and 72%. Both conventional and novel image-charge detection techniques were used for these studies. The novel version of a charge detector that was demonstrated was fabricated using patterned metal electrodes on printed circuit boards. The simplicity and versatility of this method was demonstrated with a multi-stage charge detector, a unique bouncing detector, and charge-detection mass spectrometry detector which is capable of measuring the absolute mass of a single highly-charged particle.
THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: XV. FINE STRUCTURE IN RUST-INFECTED WHEAT LEAVES
Electron microscopy showed that the haustoria of P. graminis tritici on wheat were characterized by numerous mitochondria, an extensive endoplasmic reticulum, densely packed ribosomes, and a well-defined plasma membrane (plasmalemma), which was often invaginated by lomasomes. No evidence was obtained for cytoplasmic connections between the parasite and its host. Many of the haustoria formed on a resistant variety, Khapli, were necrotic but others were closely similar to those formed on a susceptible variety, Little Club. The haustorial necks were surrounded by a collar-like sheath formed by an extension of the host cell wall. The haustoria merely invaginated host protoplasts from which they were separated by granular encapsulations. The latter were apparently secreted mainly by the host and developed faster in Khapli than in Little Club. The presence of haustoria also induced the formation of an extensive, smooth-surfaced endoplasmic reticulum in the host, a contraction and fragmentation of the vacuole, a...