Restriction analysis of Thiobacillus ferrooxidans DNA using pulsed field electrophoresis]

The DNA of Thiobacillus ferrooxidans digested by any of the five restriction endonucleases (DraI, EcoRI, Eco321, HindIII, XbaI) was studied by electrophoresis in the pulsating differently directed electric fields (PF). The influence of PF conditions on the sized row of the divided DNA fragments was studied. Only the XbaI restriction endonuclease was shown to cleave the Thiobacillus ferrooxidans DNA into a number of fragments permitting one to define the sizes of fragments and genome (no more than 2300 bp). The prospects of using the restriction analysis of Thiobacillus ferrooxidans wild type culture for improving its properties in obtaining heavy metals are discussed.     

The use of ampicillin/sulbactam (Unasyn) in treating inflammatory urological diseases

Unasyn is a combination of ampicillin, a bactericidal antibiotic, and sulbactam, an inhibitor of beta-lactamases. It was used in treatment of 36 patients with urogenital infections. The combination was administered intravenously and in the main intramuscularly. The treatment course amounted to 7-10 days. The average daily dose was 6 to 9 g. 22 patients with acute nonocclusive pyelonephritis were treated with the combination and its clinical and bacteriological efficacy was stated in 95 per cent of the cases. An excellent clinical effect of the combination was observed in 6 patients with acute epididymitis. A clinical improvement was also observed in the treatment of the patients with acute prostatitis and chronic renal infections. Unasyn proved to be a highly efficient antibacterial combination with regard to gram-positive flora and colon bacilli as representatives of gram-negative organisms. Satisfactory results were also stated in the treatment of infections caused by Proteus spp. Complete elimination of the pathogen was achieved in 57.7 per cent of the cases. No adverse reactions to Unasyn except pain in the site of the injection were recorded.     

Codon usage in the vertebrate hemoglobins and its implications

A study of codon usage in vertebrate hemoglobins revealed an evolutionary trend toward elevated numbers of CpG codon boundary pairs in mammalian hemoglobin alpha genes. Selection for CpG codon boundaries countering the generally observed CpG suppression is strongly suggested by these data. These observations parallel recently published experimental results that indicate that constitutive expression of the human alpha-globin gene appears to be determined by regulatory information encoded within the structural gene. The possibility is raised that, in the absence of selection, CpG decay can be used to date the evolutionary origin of a mammalian alpha pseudogene from its active alpha gene.      

Effect of penicillin series antibiotics on the properties of Brucella]

Investigation of the properties of antibiotic-resistant variants obtained experimentally from various species of Brucella indicated that benzylpenicillin, ampicillin and ceporin induced significant changes in the main properties of Brucella, i.e. phagolysability, agglutinability, production of brucellacin and hydrogen sulfate, attitude to dyes. Only the nutrient requirements of Brucella did not change when it was grown on synthetic media which is of great importance for investigation of changed Brucella strains.     

A reactivity to polyclonal stimulation of immunogenesis with salmozan after its repeated administration

The injection of 100 micrograms of salmozan (polysaccharide isolated from Salmonella typhi somatic O-antigen) or 50 micrograms of Escherichia coli lipopolysaccharide into mice induced a considerable increase in the number of antibody-forming cells in the spleen in response to the injection of sheep red blood cells (SRBC) 2-3 days later. This polyclonal effect was essentially weaker if the animals previously received 500 micrograms of salmozan (9-10 days prior to the injection of SRBC). The absence of reactivity was not linked with antibodies to salmozan or with some other serum factor. The lymphocytes of nonreactive mice proved to be capable of polyclonal response in the adoptive system, and at the same time the polyclonal response of intact lymphocytes to salmozan in the body of nonreactive irradiated mice was essentially weakened. The features making the above phenomenon similar to, as well as different from, the so-called "endotoxin tolerance" are analyzed.     

The glutamine synthetase-glutamate synthase system in Rhodopseudomonas sphaeroides

The phototrophic purple bacterium Rhodopseudomonas sphaeroides, strain 2R, can assimilate ammonium by means of glutamine synthetase and glutamate synthase. A higher activity of glutamine synthetase is displayed by cells grown in the medium with glutamate or in the atmosphere of molecular nitrogen. The activity of glutamate synthase also rises when cells grow in the atmosphere of N2. However, in contrast to glutamine synthetase, the activity of glutamate synthase does not decrease in the presence of considerable NH4+ amounts. The glutamine synthetase of R. sphaeroides is modified by adenylylation/deadenylylation. In the presence of nitrogenase in R. sphaeroides, the glutamine synthetase is found mainly in the deadenylylation state. Methionine sulfone, an inhibitor of glutamine synthetase, partly restores the activity of nitrogenase in the presence of ammonium, and prevents adenylylation of glutamine synthetase.     

Growth and oxidation of sulfur compounds by Thiocapsa roseopersicina in darkness]

The purple sulphur bacterium Thiocapsa roseopersicina, strain BBS, grown in the darkness in aerobic autotrophic conditions, oxidized sulphides to free sulphur and then to sulphates. This was accompanied with the fixation of carbon dioxide by the cells. Addition of glucose to the mineral medium increased the biomass yield; the cells oxidized thiosulphate still at a high rate. These results prove the possibility of switching T. roseopersicina from photosynthesis to a dark chemolithautotrophic way of life.     

The use of pulsed field electrophoresis using diversely directed electrical fields for establishing the degree of similarity of three Pseudomonas cultures]

It has been shown that from the group of three restriction endonucleases (XbaI, Uba 78I, DraI) only XbaI digests the native Pseudomonas genomic DNA into the number of fragments, sufficient for their comparative analysis. Optimal electrophoresis conditions were adjusted for the better DNA restricts separation. Each Pseudomonas culture gives unique patterns of DNA restriction. The calculation of the conservative fragments fraction content in the samples led us to the conclusion that P. fluorescens differs equally from both P. fluorescens 80 and P. alcaligenes. The P. fluorescens 80 DNA contains a relatively larger number of fragments equal in size with those of P. alcaligenes DNA, than DNA of P. fluorescens. We have concluded that the systematics of the Pseudomonas genus is still imperfect and that the analysis of DNA restriction patterns is necessary for the estimation of the similarity level of cultures studied.