Method of isolating pathogenic enterobacteria from atmospheric air]

The authors present comparative results of determination of sedimentation and aspiration methods of air pollution by pathogenic enterobacteria during the artificial sewage "raining". Results (in per cent) of isolation of salmonellae from the air by both methods proved to be very close; however, a possibility of isolation of pathogenic bacteria from the air increased with the use of the apparatus for the examination of large air volumes.     

Relation of intrahospital morbidity from staphylococcal infections to some properties of hospital strains]

Analysis of staphylococcus infection morbidity in a large obstetrical hospital for 5 years offered a possibility of establishing an association between the severity of the course of staphylococcus infections in patients, the bacteriophage type of the causative agent and its resistance to antibiotics. The qualitative changes in morbidity in the direction of the prevalence of minor forms and mild course ocurred in parallel with the changes of the leading bacteriophage type from the epidemic 75/77 and 80/81 to the nonepidemic bacteriophage types of the III bacteriophage group and the changes of the antibiograms of the causative agents in the direction of an increase in the number of strains sensitive to antibiotics. Since the severity of the course of staphylococcus infection characterized the pathogenicity of the strain of the causative agent a conclusion could be drawn on the association between the sign of virulence and determinants of the medicinal resistance and definite prophages in the hospital strains of staphylococcus.     

Method for isolating cyanobacteria-lysing streptomycetes from soil

A new technique is described for the isolation and enumeration of cyanobacteria-lysing Streptomyces spp from soil or water. Two cyanobacteria, Anabaena cylindrica (ACTT 27899) and Tolypothrix tenuis (ATCC 27914) were used as the test organisms. Ten-day-old cyanobacterial cultures were vacuum-filtered to form a lawn on a 7 cm Whatman No. 1 filter paper which was then supported on Allen's agar. When the lawn was inoculated with dilutions of a heavy clay prairie soil and incubated at 27 PT 1dEC under constant illumination, white or grey colonies of streptomycetes grew. These colonies were surrounded by zones where a yellowing and lysis of the algal cells occurred. Streptomyces achromogenes was identified as a major lytic species within a population of 5 times 10₃ plaque-producing streptomycetes/g (dry weight) soil.     

Method of isolating isoflavone aglycones from soya beans

The method of isolating isoflavone aglycones from soya beans has been proposed. The procedure includes the extraction by hot water, glycosides oxidative hydrolysis, aglycones extracting by ethyl acetate and removing the lipophilic substances by means of hexanic extraction. The aglycones outcome is not less than 80%. The preparation obtained contains over 50% of soya bean aglycones.     

Method of isolating photochemically active pigmet-proteolipid complexes from chloroplasts]

The paper deals with the chromatography isolation method of pigment-lipoprotein complexes of photosystem I and II of pea chloroplasts on the DEAE-cellulose. The componenet composition and photochemical properties of isolated complexes are compared with the data available in literature concerning similar objects. The question about the use of pigment-lipoprotein complexes as the model systems for investigating structure organization and functional characteristics of different parts of the chloroplast photosynthetic apparatus is under discussion.     

Rapid and efficient extraction of soluble proteins from Gram-negative microorganisms without disruption of cell walls

The ability of buffer solutions containing low concentrations of nonionic detergents (Triton X-100, Tween 20, Brij 58, and Lubrol PX) and the anionic detergent sodium deoxycholate, as well as mixtures of these detergents with chaeotropes (urea and guanidine hydrochloride), to extract intracellular proteins of Gram-negative microorganisms (Escherichia coli and Pseudomonas aeruginosa) was studied. It was established that the solutions containing Triton X-100 and sodium deoxycholate and the mixtures of these detergents with urea are the most effective. It was shown that the extraction of proteins from bacterial cells under the studied conditions is not accompanied by a release of DNA into solution but is associated with extraction of low-molecular RNAs. The level of protein extraction reaches 80%. No disruption of the bacterial cell wall occurs during the extraction, and proteins probably penetrate through meshes of the murein network. The efficiencies of our buffer mixtures are close to or higher than that of the commercial reagent CelLytic B (Sigma, United States). The practical uses of the chaeotropic mixtures developed are discussed.     

Nature of the IR spectra of intact cells of Gram-negative microorganisms

The character of changes in the infrared spectra of E. coli in the process of their mechanical disintegration has been studied. The destruction of E. coli cell structures has been shown to produce no changes in the optical density of the main analytical absorption bands in infrared spectra. This fact suggests that the infrared absorption spectra of E. coli are the sum of the spectra of all chemical components of the cell, which is confirmed by the infrared spectral study of E. coli cell-wall preparations. Similar results have been obtained in the study of the preparations of B. pertussis cell walls, protoplasts and intact cells.     

Treatment of Gram-negative bacterial infections by potentiation of antibiotics

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The importance of black-pigmented Gram-negative anaerobes in human infections

Abstract Black-pigmented Gram-negative anaerobic rods are found on mucosal surfaces as indigenous flora. With mucosal damage due to disease, trauma or surgery, these organisms may invade tissues and set up infection. Other important factors determining whether or not infection results include ‘inoculum’ size, synergy with other organisms and production of virulence factors that include capsules, lipopolysaccharide, attachment factors, proteases, collagenase, neuraminidase, and phospholipase A; also, they may have fibrinolytic and anti-phagocytic activity and may degrade complement and IgG and IgM. Pigmented anaerobes are found in all types of infections including such serious infections as bacteraemia, endocarditis, intracranial abscess, necrotizing pneumonia and necrotizing fasciitis, generally as part of a mixed infecting flora, and they play a key role in experimental mixed infections. They dominate or are prominent in infections involving organisms originating in the oropharynx, such as central nervous system, head and neck, dental and pleuropulmonary infections. Therapy of infections involving pigmented anaerobes includes surgery plus antimicrobial agents; a significant percentage of strains produce β-lactamase. Much remains to be done to determine the relative importance of the various taxa of black-pigmented Gram-negative anaerobes and of the different virulence factors produced by them.     

Use of lincomycin, methicillin and ristomycin in the nutrient media for isolating pathogenic intestinal microorganisms]

Elective-differentiating solid nutrient media for simultaneous isolation of Vibrioes, Salmonella and Shigella were developed. Antibiotics active against grampostive microflora and dry bile salts inhibiting the growth of Proteus were used as the inhibitors of the growth of the accompanying microflora. The medium was lincomycin and the bile salts may be prepared in a dry form.     

Transformation of Gram-positive microorganisms with the Gram-negative broad-host-range cosmid vector pJRD215

Abstract In an in vitro direct assay with tissue-type plasminogen activator (tPA), plasminogen and the chromogenic substrate S-2251, the ability of Mycoplasma fermentans KL4 to stimulate tPA-mediated activation of plasminogen to plasmin was studied. Mycoplasma cells markedly enhanced the activation of plasminogen by tPA in a concentration-, temperature- and pH-dependent manner. Nonidet P-40 (0.01%), sonication, and freezing and thawing of the cells substantially increased the stimulatory effect of mycoplasma on tPA activity. In contrast, the activation of plasminogen by urokinase was refractory to mycoplasma cells. The mycoplasma-mediated stimulation of tPA activity was prevented by ϵ-aminocaproic acid (EACA), a lysine analogue known to block lysine-binding sites (LBS) in plasminogen and tPA. Among several Mycoplasma fermentans strains tested, incognitus strain demonstrated the highest stimulation activity. These results suggest that mycoplasma cells interact with LBS in tPA and plasminogen to enhance plasminogen activation.