The ultrastructure of spores ofClaviceps purpurea (Fr.) Tul.

The ultrastructure of saprophytic and parasitic spores of the AscomyceteClaviceps purpurea (Fr.) Tul. was studied. Considerable differences were found to exist between the saprophytic and parasitic spores as to morphology and fine structure. The reason for the different ultrastructural morphology is probably connected with the intensity of cell metabolism. Whereas the parasitic spores obtained from the honeydew possess the character of a resting cell with a thick electron-dense cytoplasm, abundant lipid bodies, few mitochondria, an underdeveloped and hence little active endoplasmic reticulum and with a homogenous thick cell wall, the saprophytic spores appear as cells with higher metabolic rate, containing more numerous mitochondria, a thinner cytoplasm, a highly developed endoplasmic reticulum, fewer lipid bodies and abundant large vacuoles as well as frequently a new wall layer.     

Cultivation of the yeastCandida lipolytica on hydrocarbon

The ability of the yeastCandida lipolytica 4-1 to oxidize and utilize various pure aliphatic hydrocarbons occurring in gas oil was studied. It was found that the given strain ofCandida lipolytica oxidized n-alkanes without adaptation, starting with heptane, and utilized them for growth, starting with nonane. Isoalkanes with a single methyl group in the side chain were also oxidized and utilized for growth, but less than the corresponding n-alkanes. The site of the methyl group in the isoalkane chain influences its conversion to biomass. Branched chains at both ends of the isoalkane molecule prevent its utilization for growth ofCandida lipolytica. 1-olefines are also oxidized and utilized for growth, though less than the corresponding n-paraffins. Alkylaromatic hydrocarbons are oxidized from amylbenzene up to decylbenzene, which is utilized only slightly for growth of the yeast.     

New data on the toxic and radioprotective effect of cysteine onEscherichia coli 15 T- cells

Summary Exponential phase cultures ofE. coli 15 T^- cells growing on glucosemineral medium were supplemented with 2 mM l-cysteine-HCl. The optical density, acid soluble SH (AS-SH) as well as the DNA, RNA, and protein synthesis of the cultures were examined during this treatment and after return to normal growth conditions. Similarly, the survival of cells irradiated by a standard X-ray dose in cysteine-free buffer was measured.The development of radioresistance during the cysteine treatment as well as the loss of this acquired radioresistance after return to normal growth conditions could be divided into two phases: a) an instantaneous and b) a slow change of radioresistance. Phase a seems to be related to the changes occurring in the AS-SH content of the bacteria, while phase b is apparently dependent on the alterations in the synthesis of macromolecules.This work was partly presented at the 6th Annual Meeting of the European Society for Radiation Biology, Interlaken 1968.