Biochemical and serologic study of Acholeplasmae isolated from monkeys

Biochemical and serological properties of mycoplasmas isolated from the blood, feces and parenchymatous organs of monkeys have been studied to determine their species. It was established that the isolated strains belong to the family Acholeplasmatoceae. The study of their biochemical properties in different tests has revealed the presence of 5 biochemically heterogeneous groups. Their serological properties suggest that 13 out of 45 strains are identical to the reference strain of A. laidlawii A, and all other strains have been classified as new Acholeplasma species which have never been isolated from monkeys before.     

Virulence and toxigenicity of Pseudomonas aeruginosa cultures of various origins

The virulence and toxigenicity of newly isolated P. aeruginosa strains have been studied in experiments on white mice. These biological properties have been shown to be most pronounced in P. aeruginosa strains isolated from proteins, sometimes greatly exceeding those in strains isolated from healthy persons and the environment. Virulence and the factors which determine it are definitely interrelated in microorganisms and can vary, depending on the conditions of their habitat.     

Entomopathogenic bacteria Bacillus thuringiensis as producers of restriction endonucleases

A total of 115 collection strains of Bacillus thuringiensis, belonging to various subspecies, have been studied for the presence of DNA restriction-modification systems. Restriction endonucleases of 13 strains have been isolated and characterized. No considerable correlations between the taxonomic positions of the bacteria and the specificities of the endonucleases isolated have been detected. It is concluded that the enzymes with identical specificities are present in both the crystalliferous and acrystalliferous strains of the same subspecies.     

Characteristics of Pseudomonas aeruginosa pili and an elucidation of their relation to the virulence of the bacteria

The electron microscopic study of 175 P. aeruginosa museum and newly isolated strains has been made and their virulence has been determined. In 32% of these strains the presence of pili has been established. However, among the museum strains those with pili have been found to constitute only 19.5%, while among newly isolated strains pili have been detected in 39.7% of cases (the difference is statistically significant at p less than 0.01). No correlation between the formation of pili and the virulence of P. aeruginosa has been established.     

The biological properties of Salmonella strains isolated from adult patients at different seasons of the year]

Biological properties of Salmonella strains, isolated in different seasons from patients with the corresponding disease of moderate severity, were compared. Their morphological, biochemical, serologic properties, sensitivity to antibiotics, capacity for synthesizing O-antigen, as well as their virulence for experimental animals, have been studied. Seasonal changes in the virulence of Salmonella strains have been established: the strains isolated in autumn have proved to be more virulent than those isolated in winter. In winter the isolation rate of Salmonella strains resistant to the therapeutic doses of antibiotics is significantly higher than in other seasons. In spring and summer Salmonella O-antigen is synthesized more intensively.     

Sensitivity of Neisseria gonorrhoeae to antibiotics]

Since 1976 strains of Neisseria gonorrhoeae producing beta-lactamase have been isolated in many countries. Strains with high level resistance to tetracycline have been also described. The appearance of resistant strains implies a constant surveillance of the isolated gonococcus and the study of their antibiotics sensitivity.     

Characteristics and utilities of luminescent bacteria from the Black sea

Luminescent bacteria, isolated from summer specimens of water of the Black sea, have been identified as strains of Photobacterium phosphoreum and Vibrio fischeri (two of each). Morphological, physiological, and biochemical properties of the four strains have been characterized, and the kinetic behavior of luciferases isolated therefrom has been studied. The sensitivity of the luminescence of the strains to certain toxic agents has been compared to that of the test strain Ph. phosphoreum (Cohn) Ford. The results obtained indicate that the new strains show promise as bioindicators.     

Entomopathogenic Bacteria Bacillus thuringiensis as Producers of Restriction Endonucleases

A total of 115 collection strains of Bacillus thuringiensis, belonging to various subspecies, have been studied for the presence of DNA restriction–modification systems. Restriction endonucleases of 13 strains have been isolated and characterized. No considerable correlations between the taxonomic positions of the bacteria and the specificities of the endonucleases isolated have been detected. It is concluded that the enzymes with identical specificities are present in both the crystalliferous and acrystalliferous strains of the same subspecies.     

The quantitative determination of the DNAse activity in Staphylococcus aureus isolated from monkeys

A new, cheaper and more sensitive method for the quantitative determination of DNAase produced by S. aureus is described. The method permits the determination of DNAase activity in a wider range of titers. The method is based on the detection of the depolymerizing action of staphylococcal nuclease on DNA dyed with ethidium bromide. In this work 22 S. aureus strains isolated from monkeys and 12 strains isolated from humans have been used. The amount of produced by these strains has been determined. The DNAase results of this determination have shown that among S. aureus strains isolated from monkeys and humans the occurrence of strains with both high and low DNAase activity can be observed.     

Utilities of Luminous Bacteria from the Black Sea

Luminous bacteria, isolated from summer specimens of water of the Black Sea, have been identified as strains of Photobacterium phosphoreum and Vibrio fischeri (two of each). Morphological, physiological, and biochemical properties of the four strains have been characterized, and the kinetic behavior of luciferases isolated therefrom has been studied. The sensitivity of the luminescence of the strains to certain toxic agents has been compared to that of the test strain Ph. phosphoreum (Cohn) Ford. The results obtained indicate that the new strains show promise as bioindicators.     

Study of genetic diversity of nontypeable Haemophilus influenzae strains isolated from healthy children and patients with infection symptoms

In the study the usefulness of genotyping methods for genetic variability examinations of non-typeable H. influenzae strains circulating in population as well as level the variability of NTHi strains isolated from healthy children and from symptomatic infection cases have been evaluated. Among genotyping methods evaluated, AFLP method of the MfeI/BglII set has been found most useful to study level of genetic variability of NTHi strains population. It has been shown that NTHi strains colonizing nasopharyngeal of healthy children present higher polymorphism level than strains isolated from patient with clinical symptoms of NTHi infection.     

Inhibition by glycine of the growth of methylotrophic bacteria : Some resistant mutants

Summary The action of glycine as an inhibitor to different species of methylotrophic bacteria possesing the serine pathway has been shown. With all the strains, glycine-resistant mutants have been obtained. A comparative study of growth parameters for both the mutant and wild strains has, been made. Better gram negative strains have been isolated but the same cannot be said for the gram positive strains.     

Culture properties of the causative agent of tularemia isolated in natural foci in Stavropol Territory, the Kalmyk ASSR and the Armenian SSR

The strains isolated in natural foci of the Stavropol Territory and the Armenian SSR have been found to belong to the holarctic race of Francisella tularensis, biovar II. In natural foci of the Kalmyk ASSR the strains belonging to biovars I and II have been isolated. The study of the tularecinogenicity of the cultures has revealed the existence of strains which are not sensitive to their own tularecins. The phenomenon of tularecinogenicity in F. novocida has been established. Avirulent strain 319/38 belonging to the non-arctic race is recommended as an indicator strain for the determination of tularecinogenicity.     

Glutamine synthetase content and immunochemical analysis of different strains of Bordetella pertussis

In this investigation 3 groups of strains isolated from pertussis patients have been studied: typical (group 1), atypical in their cultural properties (group 2), unidentified Gram-negative bacilli agglutinated by pertussis and parapertussis antitoxins (group 3). Besides, B. pertussis cultures, obtained by subculturing 2 museum strains and 2 newly isolated strains on synthetic casein-charcoal agar with subinhibiting doses of antibiotics or specific immune sera added, have been studied. As indicated by the results of this study, strains belonging to groups 1 and 2 contain glutamine synthetase, while in strains of group 3 this enzyme is absent. In immunoelectrophoresis strains of group 3 have been found to contain not a single antigen similar to the antigens of strains belonging to groups 1 and 2. Electrophoresis in polyacrylamide gel has revealed to differences in the protein spectrum of the strains of these 3 groups. The investigation has shown that the determination of glutamine synthetase and immunoelectrophoresis can be used for the differentiation of B. pertussis from similar Gram-negative bacilli. B. pertussis strains, changed as the result of experiments with antibiotics and specific immune sera, have also been shown to retain their antigenic composition and protein spectrum and to have no essential difference in the content of glutamine synthetase.     

Outer membrane proteins in the characterization of salmonellae of various origins

Outer membrane proteins have been studied in 76 Salmonella strains isolated from various sources and differing in their sensitivity to antibiotics, the presence of R-plasmids and a number of enzymatic properties. The outer membranes have been isolated by the modified method of L. W. Coulton and D. T. F. Wan. The study of the isolated proteins has been carried out by means of gel and disc electrophoresis in polyacrylamide gel with sodium dodecyl sulfate according to K. Weber and M. Osborn. The composition of the proteinograms thus obtained has revealed the presence of essential differences between hospital strains and cultures isolated from animals and from the environment in sporadic infections, as well as between strains belonging to different serovars. The possibility of using the characterization of outer membrane proteins of salmonellae in epidemiological investigations is discussed.     

Isolation of highly performant sulfate reducers from sulfate-rich environments

Eleven pure strains of sulfate-reducing bacteria have been isolated from lab-scale bioreactors or gypsum disposal sites, all featuring relatively high concentrations of sulfate, and from natural environments in order to produce sulfide from gypsum using hydrogen as energy source. The properties of the eleven strains have been investigated and compared to these of three collection strains i.e. Desulfovibrio desulfuricans and Dv. vulgaris and Desulfotomaculum orientis. Particular attention was paid to the volumetric and specific sulfide production rate and to the hydrogen sulfide inhibition level. By comparison to the three collection strains, a 75% higher production rate and a hydrogen sulfide inhibition level about twice as high i.e. 25.1 mM have been achieved with strains isolated from sulfate-rich environments. The strain selection, particularly from sulfate-rich environments, should be considered as an optimization factor for the sulfate reduction processes.     

Characterization and genetic variability of Fusarium verticillioides strains isolated from corn and sorghum in Brazil based on fumonisins production, microsatellites, mating type locus, and mating crosses

Fusarium verticillioides (Gibberella fujikuroi mating population A) is a producer of fumonisins and one of the main contaminants of corn grains. In Brazil, some studies analyzing strains isolated from corn have demonstrated high levels of fumonisins, whereas the levels for strains isolated from sorghum have been found to be low. In the present study, we investigated the genetic diversity of 22 F. verticillioides strains isolated from corn and 21 strains isolated from sorghum cultivated in the State of S?o Paulo, Brazil. Differences in the genetic profile were observed between the strains isolated from the two substrates using single primer amplification reaction by polymerase chain reaction (SPAR-PCR). Fumonisins levels were higher in strains isolated from corn than in those isolated from sorghum. The MAT-1 and MAT-2 alleles were identified by PCR, and the isolates were subsequently crossed with Fusarium thapsinum (G. fujikuroi mating population F) reference strains because this species is morphologically similar to F. verticillioides and produces low levels of fumonisins. The SPAR haplotypes of some strains isolated from sorghum were similar to the F. thapsinum reference strain haplotypes, but there was no fertile mating between the strains isolated from the two substrates and the F. thapsinum references strains. The MAT-1:MAT-2 proportion was 5:17 and 14:7 for isolates from corn and sorghum, respectively.     

Phage typing of the coagulase-positive staphylococci isolated from various species of animals

More than 200 coagulase-positive strains of animal origin have been studied by means of Staphylococcus aureus typing phages, belonging to two international sets and intended for typing staphylococci isolated from large cattle and humans, and experimental "chicken" phage A 1591. Among S. aureus strains the cultures isolated from swine, cows, chickens, and belonging to biotypes B1, C1, B2, respectively, have been mostly (in 78.5-90.0% of cases) determined by phage typing. The strains belonging to one biotype have proved to be sensitive predominantly to the same phages. In this connection further differentiation of staphylococci within individual biotypes by means of the phages used in these experiments seems to be impracticable. S. intermedius strains have been found to be completely resistant to the above phages, which confirms that S. intermedius is rightly considered to be an independent species of coagulase-positive staphylococci.     

Phenytoin teratogenicity in the primary and secondary mouse embryonic palate is influenced by the H-2 histocompatibility locus

Inbred and congenic strains of mice have been studied for susceptibility to phenytoin-induced cleft lip with or without cleft palate (CLP) and isolated cleft palate (CP). The role of genes linked to the H-2 complex on chromosome 17 has been confirmed. Congenic strains with the A background have identical levels of spontaneous CLP, whereas those strains having the A background with the H-2a haplotype have significantly higher rates of induced CLP than their congenic partners with the H-2b or H-2s haplotype. No such significant difference in the degree of CLP produced by phenytoin is demonstrable in strains with the B background. Rates of isolated CP produced by phenytoin are significantly higher in strains with H-2a than in their congenic partner strains with either H-2b or H-2s, whether the background is A or B.     

Adhesion in meningococcus

The adhesive activity of 113 meningococcal strains with different invasive properties and 10 Neisseria nonpathogenic strains have been studied. Adhesive properties have been revealed in 80-82% of these strains. Meningococcal strains isolated from the nasopharynx of carriers possess high hemagglutinating activity. The percentage of cells with pili in these strain was also higher than that in meningococcal strains isolated from the liquor of patients. This shows the presence of direct correlation between the number of pili in the cells (according to the data of electron microscopy) and their activity in the hemagglutination test, which makes it possible to use this test for the determination of the adhesive capacity of meningococci, associated with the presence of pili.