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861.
Trypanosoma cruzi: experimental immunization of mice 总被引:2,自引:0,他引:2
862.
863.
The spores ofBacillus cereus can be germinated in reasonable synchrony in rich media. The survival of germinating cells after UV irradiation is strongly
affected by repair. When plating on mineral agar a linear decrease of survival is obtained between 20–60 min of germination,
whereas the survival on nutrient agar shows only minor fluctuations. The difference in survival on these two media which reached
1–2 orders of magnitude is due mostly to the shape of the shoulder on the survival curve. Survival on mineral agar may be
increased by postincubation in complex media or by preincubation in mineral media. It was concluded that repression and derepression
of biosynthetic pathways was responsible for the different efficiency of repair. 相似文献
864.
It was found that ethionine partially inhibits the transport of the inducer (TMG) of β-galactosidase into the cells ofEscherichia coli ML-30. The synthesis of β-galactosidase-specific messenger RNA is not inhibited. Ethionine appears to be incorporated into
proteins synthesized by the strains used. The incorporation of ethionine into the molecule of β-galactosidase results in the
synthesis of an enzymically inactive, immunologically cross-reacting protein. 相似文献
865.
Manometric studies were carried out on the respiratory activity of different rhizosphere and non-rhizosphere soils to follow
quantitatively the over-all microbial activity in the rhizosphere soil as affected by the species and growth phase of plant.
Oxygen consumption was distinctly greater in rhizosphere soils as compared to that in non-rhizosphere soils. The difference
between oxygen consumption by rhizosphere and non-rhizosphere soils changed with the course of plant growth and it was not
the same in different plants. This difference in oxygen consumption might be a measure of the amount of available oxidizable
substrate in the rhizosphere. A rhizosphere sample had greater diversity as well as higher concentration of free amino acids
than a non-rhizosphere sample of the same soil. Bacterial counts pointed to preferential stimulation in the rhizosphere of
bacteria requiring individual amino acids. amino acids, such as glycine, alanine, asparsic acid of tyrosine were oxidized
more rapidly in rhizosphere than in non-rhizosphere soil, but the extsent of oxidation for each of the amino acids studied
did not differ. The amount of oxygen consumed during oxidation of alanine, aspartic acid or tyrosine was about one-half of
the total amount necessary for complete oxidation. With glycine a higher extent of oxidation (60%) was observed. These extents
of oxidation of glycine and aspartic acid did not change on investigation at two different phases of plant growth. 相似文献
866.
867.
L. Prokešová 《Folia microbiologica》1969,14(1):82-88
IgM was isolated from pig serum by isoelectric precipitation and gel filtration. Different methods of breaking down the disulphide
bonds and of isolating subunits of the IgM molecule—oxidative sulphitolysis and reduction by 0.1m 2-mercaptoethanol in the absence of a disaggregating agent, oxidative sulphitolysis in the presence of 6m urea and reduction by 0.3m 2-mercaptoethanol in medium containing 6m and 8m urea—were compared. Degraded material was separated by gel filtration on Sephadex G-100 or G-200 in 0.05m formic acid with 6m or 8m urea. Oxidative sulphitolysis or reduction by 0.1m 2-mercaptoethanol without a disaggregating agent did not yield pure H andl chains. Oxidative sulphitolysis was the more effective. Oxidative sulphitolysis in 6m urea medium severely damaged the material. Reduction of IgM by 0.3m 2-mercaptoethanol in 6m or 8m urea also altered its immunochemical properties. The possible presence of light chains in the heavy chain fraction cannot
likewise be excluded in this case. The results are in agreement with experiments showing that the molecular weight of the
IgM heavy chain is greater than that of the IgG heavy chain. 相似文献
868.
869.
870.