Acta microbiologica Polonica. Series A: Microbiologia generalis最新文献

Seven Mycobacterium strains were grown statically on salts-glycerol-asparagine (Sauton) or on salts-glucose-glutamate (Sym) media. At desired time of incubation, the bacteria were washed with water, disintegrated with powdered corundum and in resulting cell-free extracts L-asparaginase activity was determined by the Conway method. The majority of experiments were performed on M. phlei which exhibited considerable rise in L-asparaginase activity with increasing age of the culture. This change did not occur on Sym medium because of Zn2+, which proved to abolish the effect of the enzyme induction in vivo but did not inhibit the activity in vitro. Addition of rifampicin to Sauton culture media resulted in a low enzyme level. Exogenous asparagine and glycerol were not indispensable for the enzyme synthesis and could be replaced by glutamate and glucose, respectively.

An attempt of chacteristization of tick-borne encephalitis virus strains, isolated in Poland in 1955--1970, was based on the determination and analysis of neurovirulence for white mice at intracerbral and subcutaneous virus inoculation, neuroinvasion, antigenic properties, cytopathogenic abilities, susceptibility to nonspecific hemagglutination inhibitors, susceptibility to temperature of 50degree and to 2M urea. Strains isolated in different regions of the country showed certain differentiation in pathogenic and antigenic properties as well in susceptibility to nonspecific inhibitors.

32P-labeled Escherichia coli WP-2 and Escherichia coli WP-2S cells were stored at minus 196 degrees. The lethal effect induced by 32P decay was equal in both strains. Lethal efficiency of 32P leads to 32P transmutation in DNA amounted to 0.046. Reversion try leads to try+ were induced with a ten times higher efficiency in UV--sensitive strain WP-2S, as compared with strain WP-2.

Differential induction of cultures of Rhizopus nigricans indicated that hydroxylation of progesterone at the 11alpha- and 17alpha-positions is due to two separate enzymes. This is supported by the finding that 11alpha- and 17alpha-hydroxylating activities are separated by differential centrigufation of cell-free extracts. The feasibility of introducing a hydroxyl group at the 11alpha- or 17alpha-position of hydroxylated progesterone derivatives was tested.

Six strains with an increased nitrous acid sensitivity were isolated (Fig. 1). The putative HNO2-sensitive mutants, as well as the parental strain 55R5 behaved abnormally in crosses, so that studies on the segregation of the sensitivity were difficult and unreliable. During 1.5 years the oversensitivity of the mutants gradually decreased to disappear completely (Tab. V). The differences in HNO2 sensitivity between respiratory-sufficient and cytoplasmic respiratory-deficient strains (Tab. I), as well as between different respiratory-sufficient strains (Tab. II-IV) are analysed.

Studies on the antigenic composition of 84 diagnostic strains of S. flexneri serotype 4a and their Lac+ recombinants from a cross with E. coli HfrC were carried out. Considerable differentiation of agglutination reaction was found both in original material and in recombinants. An interesting group included recombinants which completely lost their capability to agglutinate with sera specific for type and group antigens and preserved only the capability to agglutinate in the polyvalent serum of S. flexneri subgroup. One of them (recombinant 140 Lac+) had been subject to detailed serological analysis and was shown to acquire as a result of recombination a new antigen appearing neither in any flexneri subgroup serotype, nor in dysenteriae and boydii subgroups. This antigen is of thermostable character.

The morphological and karyological properties as well as susceptibility to virus strain of tissue culture derived from human embryo lung that underwent a transformation becoming a continuous line defined as PZH-1 were observed. The observations cover 120 passages divided into four phases: one before and three after transformation. Each of these phases was characterised by different biological strain properties. Loss of PZH-1 susceptibility to ECHO virus was the first change of biological properties preceding in time changes in growth rate, cell morphology and chromosome complement. The loss of susceptibility to ECHO virus may indicate cell transformation.

The rate of phage 1P attachment to Rhizobium cell walls was increased in the presence of ethylenediaminetetraacetic acid (EDTA). On the other hand the rate of adsorption of phage 1P to the Triton -- insoluble cell walls was diminished. The subsequent treatment of cell walls with 2% Triton X-100 and 5mM EDTA caused a more substantial decline of the phage inactivating capacity. Lipopolysaccharides (LPS) isolated from the sensitive strains, contrary to those from phage-resistant mutants, inactivated effectively phage 1P. The content of sugars in LPS preparations was determined by using gas liquid chromatography.

The reverse mutation to the wild type of lambda sus 9 and T4 AM B17 bacteriophages, grown in bacteria prelabeled with 35S and stored at--196 degrees, was studied. No mutagenic effect of 35S was observed in both, lambda and T4 bacteriophages. It is suggested that there is no influence of 35S disintegrations on the properties of DNA polymerase to which the mutagenic activity could be attributed.