Immunological characterization of the cytochrome o terminal oxidase from Escherichia coli

The cytochrome o terminal oxidase from Escherichia coli was immunochemically purified and monospecific antiserum toward cytochrome o was obtained. This antiserum is able to precipitate 100% of the ubiquinol-1 oxidase activity in Triton X-100 extracts of membranes from an E. coli strain in which cytochrome o is the only terminal oxidase. Cytochrome o was analyzed and quantitated using crossed immunoelectrophoresis, rocket immunoelectrophoresis, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis shows that cytochrome o is composed of four subunits of approximate equimolar stoichiometry with molecular weights of 51,000, 28,500, 18,000, and 12,700. The low temperature (77 K) reduced - oxidized spectrum of the immunoprecipitate shows two peaks at 555 and 562 nm, indicating b-type cytochromes. With the anti-cytochrome o and antiserum toward the cytochrome d terminal oxidase complex which was previously obtained, it is possible to immunochemically assay for all the cytochromes in the cytoplasmic membrane of aerobically grown E. coli. Preliminary results indicate that the biosynthesis of cytochrome o is repressed when cytochrome d is induced by lowering the dissolved oxygen concentration during cell growth.     

Clinico-epidemiological characteristics of Q fever in the Carpathian region

The study of the specific epidemiological and clinical features of Q fever revealed the existence of an active focus of infection among humans due to their contacts with agricultural animals in one of the districts of the region. The focus was manifested by group morbidity among the cattle-tending personnel of a dairy farm. The source of this infection was cattle. The infection was transferred mainly through the air. The disease took a moderately severe course. The study of the rickettsial contamination of humans, animals and ticks suggested the presence of the active epidemic process and made it possible to work out concrete antiepidemic measures.     

A specific decrease in collagen synthesis in acutely fasted, vitamin C-supplemented, guinea pigs

Weight loss often results from various experimental conditions including scurvy in guinea pigs, where we showed that decreased collagen synthesis was directly related to weight loss, rather than to defective proline hydroxylation (Chojkier, M., Spanheimer, R., and Peterkofsky, B. (1983) J. Clin. Invest. 72, 826-835). In the study described here, this effect was reproduced by acutely fasting normal guinea pigs receiving vitamin C, as determined by measuring collagen and non-collagen protein production after labeling tissues in vitro with [3H]proline. Collagen production (dpm/microgram of DNA) decreased soon after initiating fasting and by 96 h it had reached levels 8-12% of control values. Effects on non-collagen protein were much less severe, so that the percentage of collagen synthesis relative to total protein synthesis was 20-25% of control values after a 96-h fast. These effects were not due to changes in the specific radioactivity of free proline. Refeeding reversed the effects on non-collagen protein production within 24 h, but collagen production did not return to normal until 96 h. The effect of fasting on collagen production was independent of age, sex, ascorbate status, species of animal, and type of connective tissue and also was seen with in vivo labeling. Pulse-chase experiments and analysis of labeled and pre-existing proteins by gel electrophoresis showed no evidence of increased collagen degradation as a result of fasting. Procollagen mRNA was decreased in tissues of fasted animals as determined by cell-free translation and dot-blot hybridization with cDNA probes. In contrast, there was no decrease in translatable mRNAs for non-collagen proteins. These results suggest that loss of nutritional factors other than vitamin C lead to a rapid, specific decrease in collagen synthesis mainly through modulation of mRNA levels.     

Tunicamycin-resistant mutants of Bacillus amyloliquefaciens are deficient in amylase, protease and penicillinase synthesis and have altered sensitivity to antibiotics and autolysis

Mutants of Bacillus amyloliquefaciens resistant to at least 10 micrograms/ml of tunicamycin were isolated and shown to be pleiotropic. The mutants were more resistant to streptomycin, chloramphenicol, kanamycin and neomycin than was the parent strain but less resistant to penicillin G and tetracycline. They were more autolytic, presumably due to an altered cell wall. The mutants produced reduced levels of amylase, penicillinase and both metal and serine protease besides having an enhanced sporulation frequency and being more motile.     

On the biosynthesis of biotin in Achromobacter IVSW a reinvestigation

[3-¹⁴C, ³⁵S]-L-cysteine was tested as precursor of biotin in Achromobacter IVSW. No significant incorporation was observed, in contradiction with the data previously reported. On the other hand, Achromobacter IVSW converts [³H, ¹⁴C]-dethiobiotin into biotin. This suggests that biotin is biosynthesized in Achromobacter according to the classical dethiobiotin pathway.     

Neurospecific proteins in human malignant brain tumors

The content of neurospecific proteins S-100, GFA and D2 was measured in malignant cerebral tumors by electrophoresis with the use of monospecific antisera. Concomitant measurement of proteins S-100 and GFA is a more reliable diagnostic criterion as to the tumor histogenesis than study of each protein alone. D2 protein appeared to be the most stable specific marker.