摘要:

Barbituric acid is required at a level of 0.1% for maximum growth ofBacillus popilliaein a synthetic medium. However, only a trace amount of that added (~2%) disappeared from the medium during growth. A general distribution of the14C from 2-14C-barbituric acid among cell components was observed, but a small amount of the radioactivity from this isotope was consistently associated with both ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). The14C found in RNA was uniformly distributed throughout the 4 S, 16 S, and 23 S RNA fractions, and control experiments indicated that the association of14C from 2-14C-barbituric acid with the nucleic acids may occur by nonspecific absorption. The presence of barbituric acid resulted in very significant stimulation of both nucleic acid and protein synthesis. The mechanism of this stimulation is unresolved.

ISSN:0008-4166    

DOI:10.1139/m70-135

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The effect of known precursors and cofactors on vitamin B12production has been studied in a basal, chemically defined medium composed of sucrose, glutamic acid, and mineral salts. Only a carbon source, betaine, and Co2+were found to be essential for vitamin B12production. Known precursors such as methionine, δ-aminolevulinic acid, succinic acid, and 1-amino-2-propanol had no effect. Glycine was inhibitory to growth. Oxalic acid, lactic acid, 5,6-dimethylbenzimidazole, and Mo2+stimulated vitamin B12biosynthesis. Of special interest is oxalic acid, which at a level of 0.04% w/v increased vitamin production about 20%, and with washed cells could replace glutamic acid, which had been demonstrated to be essential for both growth and vitamin B12production. When use of oxalate was followed, it was found that this acid disappeared during the period of rapid growth and vitamin production and then reappeared during the final stages of the fermentation cycle.

ISSN:0008-4166    

DOI:10.1139/m70-136

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The synthesis ofalpha-ketoglutarate dehydrogenase by a species ofAcinetobactergrowing in the presence of C4compounds (succinate or malate) and in the presence of a C2compound (acetate), as sole carbon sources, has been investigated. The rate of synthesis of this enzyme is increased rapidly when cells are inoculated into a succinate medium, and growth is initiated essentially without a lag period. The enzyme is synthesized after some lag period in the presence of malate and growth begins as the rate of enzyme synthesis begins to increase. On the contrary, growth begins immediately upon inoculation of the cells into an acetate medium. After a few hours of growth the level ofalpha-ketoglutarate dehydrogenase begins to fall and apparent repression of synthesis occurs. These results are discussed in the light of isocitrate lyase levels in the cells at the same time periods and the evidence indicates that when levels ofalpha-ketoglutarate dehydrogenase are high, those of isocitrate lyase are low. This suggests a control mechanism regulating the concurrent operation of the tricarboxylic acid cycle and the glyoxylate by-pass. Data are presented also which correlate substrate oxidation by succinate-grown cells and the cellular levels ofalpha-ketoglutarate dehydrogenase.

ISSN:0008-4166    

DOI:10.1139/m70-137

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The spread of infectious virus in the tissues of mice after infection with two serologically very similar plaque mutants of Mengo virus has been determined at daily intervals. The distribution of L-Mengo (a large-plaque, virulent mutant) after intraperitoneal and intravenous administration was quite similar, indicating that after intraperitoneal injection this mutant spreads throughout the animal by way of the vascular system. Infectious virus was recovered from all tissues examined except the liver. In contrast, S-Mengo (small-plaque, avirulent) was recovered only from the spleen and lymph nodes after either intravenous or intraperitoneal injection. After intravenous injection, L-Mengo was cleared only very slowly from the bloodstream and at a rate similar to that of two strains of poliovirus. On the other hand, intravenously injected S-Mengo was completely cleared within 30 min. Starting at around 4 h post-inoculation, high titers of interferon were induced in the serum by L-Mengo, reaching a peak by 12 h and remaining elevated for at least another 12 h before declining. Since little or no interferon was found in the serum after intravenous injection of S-Mengo, heat- or ultraviolet-inactivated L-Mengo, or poliovirus types 1 and 3, it was concluded that the presence of circulating, replicating virus was required for induction. The significance of these results is discussed.

ISSN:0008-4166    

DOI:10.1139/m70-138

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Fluorescence and electron microscopy were used for examining the characteristics of bud scar formation in haploid and diploid cells ofSaccharomyces cerevisiaeas well as in zygotes. The cell wall of haploid cells gives rise to haploid scars about 1.2 μ in diameter which are arranged in rows, rings, and spirals. The surface of diploid cells displays diploid scars about 2 μ in diameter. Their topological sequence differs from that observed in haploid cells. The zygotes show both haploid scars which determine the relative cell age of the parent cells, and diploid scars which reflect the reproduction of zygotes.

ISSN:0008-4166    

DOI:10.1139/m70-139

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

On acute cold exposure the normal brown adipose cells in the mouse interscapular pad underwent morphological changes apparently as a result of loss and redistribution of the intracellular lipid globules; on continued cold exposure the globules increased in numbers and size. If adult female mice were inoculated with coxsackievirus B-3 during acute cold exposure and returned to normal room temperature soon afterwards, the viral damage in the brown adipose tissues was seriously aggravated; if on the other hand they were left in the cold for the duration of the infection, the damage was aggravated to a lesser degree. Finally, if cold-acclimated mice were inoculated the lesion was localized in one area of the pad.In contrast, the myocardial damage was aggravated only in those mice which were inoculated during acute cold exposure and left in the cold. The cox. B-3 pathogenesis in the brain showed no clear-cut variations resulting from changes in the ambient temperature. The infectious amount of virus recovered from the heart and brain appeared to be greater and persist longer, if the mice were subjected to a prolonged cold exposure.The cold exposure, however, failed completely to increase the age susceptibility of mice to cox. B-2.

ISSN:0008-4166    

DOI:10.1139/m70-140

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Penicillium funiculosum,Penicillium lilacinum, andSpicaria violaceaproduced excellent yields of dextranase if ketodextran replaced dextran as a carbon source. Ketodextrans I and II having degrees of substitution of 2 and 20% respectively were used in this study.P.funiculosumgrew equally well on dextran and ketodextran I but less well on ketodextran II. Addition of a readily metabolizable carbohydrate such as glucose, sucrose, or galactose stimulated growth on ketodextran II, resulting in better dextranase production. However, excess glucose reversed this increase in enzyme production. Replacement of an inorganic nitrogen source with an organic one further stimulated dextranase production during growth ofP.funiculosumon ketodextran II.

ISSN:0008-4166    

DOI:10.1139/m70-141

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The characteristics of growth ofFerrobacillus ferrooxidanson elemental sulfur are reported. This organism is not able to oxidize thiocyanate, but can oxidize elemental sulfur, sulfite, dithionite, thiosulfate, tetrathionate, and sulfide. Sulfide is only partially oxidized. All compounds that can be oxidized support CO2fixation.

ISSN:0008-4166    

DOI:10.1139/m70-142

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Naked and enveloped Herpes simplex virus (HSV) particles from infected HEp-2 cells were separated by sucrose density-gradient centrifugation. Infected cells deprived of arginine during the latter half of the virus growth cycle were found capable of synthesizing about the same total number of naked particles as were infected cells maintained in normal medium throughout the cycle. The formation of full capsids in arginine-deprived cells was greatly depressed. The number of enveloped virus particles in the arginine-deprived culture was one-half that of the normal culture, but those full capsids which were enveloped in both cultures were equally infectious.Evidently late arginine deprivation affects the maturation of HSV nucleocapsids, rather than the synthesis of capsid protein, and the enveloping process appears to be affected by arginine deprivation as well.

ISSN:0008-4166    

DOI:10.1139/m70-143

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

With oxidized methyl oleate as the substrate, a rapid method for the determination of microbial destruction of peroxides and monocarbonyls has been developed.Staphylococcus aureusshowed extensive destruction of peroxides by both cells and supernatant fluid, whileBacillus cereus,Micrococcus cryophilus,Serratia marcescens, andSarcina luteahad activity only in the cells.Escherichia coliwas inactive. Destruction of 2,4-dienals, 2-enals, andn-alkanals followed a similar pattern except thatE.colicells also were active against the monocarbonyl classes. Paper chromatography did not reveal any selective action against specific monocarbonyls within the classes.

ISSN:0008-4166    

DOI:10.1139/m70-144

出版商:NRC Research Press    

年代:1970

数据来源: NRC