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Biomedical subjects

S V Lysenko

Publications and source records attributed to S V Lysenko.

48 records · Page 3Linked to original sources
PubMedDate not supplied

[Action of desiccation and low temperatures on mesospheric strains of Aspergillus niger and Penicillium chrysogenum].

Aspergillus niger and Penicillium chrysogenum strains were isolated from the mesosphere and characterised. Their properties significant for migration in the atmosphere are discussed. The possibility of the anabiotic state of these fungi under the action of dehydration and low temperatures was studied as well as the degree of their resistance to the aforementioned extreme factors.

Air Microbiology↗
PubMedDate not supplied

[Action of dehydration on the survival, morphology and ultrastructure of the conidia of air-borne and culture collection strains of Aspergillus niger and Penicillium chrysogenum].

The effect of dehydration on the morphology and fine structure of conidia was studied with the atmospheric and collection strains of Aspergillus niger and Penicillium chrysogenum. Dehydration did not cause changes in the structure of most conidia. However, destructive changes in the conidial wall and membrane were found in some conidia. The cytological changes of conidia were either reversible or irreversible, which determined their survival rate during dehydration.

Air Microbiology↗
PubMedDate not supplied

[Characteristics of microorganisms subjected to the action of a vacuum].

The object of this work was to study the effect of vacuum on Endomyces magnusii, Serratia marcescens, Escherichia coli and Mycobacterium luteum. The zone of tolerance to the water activity was determined for the intact cells of E. magnusii and for the cells subjected to vacuum. Suspensions of the above cells were studied by UV spectroscopy with the aim of detecting changes in the permeability of cell membrane after the action of vacuum.

Ascomycota↗
PubMedDate not supplied

[Comparative physiological and biochemical characteristics of Aspergillus niger isolated from the mesosphere and of its mutant].

The aim of this work was to study certain physiological-biochemical characteristics of Aspergillus niger, strain 26, isolated from the mesosphere as well as those of its mutant having light-brown conidia. The parent strain and its mutant were grown in a liquid Chapek medium to study accumulation of the biomass, changes in the pH of the medium, as well as assimilation of glucose, nitrogen (NO3-) and phosphorus (PO4-). The content of polysaccharides, protein, RNA and DNA was determined in the biomass. The parent culture and its mutant had the same growth dynamics and changes in the pH of the growth medium. They assimilated nitrogen, phosphorus and glucose at the same rate. No significant differences were found in the content of DNA, RNA, protein and polysaccharides. Lipids were an exception: their content was higher by ca. 26% in the mutant as compared with the parent strain. Apparently, the elevated sensitivity of the mutant to UV is due not only to a loss of certain pigments, but also to a damage of other protective mechanisms of the cell.

Air Microbiology↗
PubMedDate not supplied

[Resistance of microorganisms of upper layers of the atmosphere to ultraviolet radiation and a high vacuum].

Solar radiation and high vacuum are the main factors affecting the incidence of microorganisms in the stratosphere and mesophere. It has been established in experiments that the conidia of Aspergillus niger are most resistant of UV irradiation. The conidia of Penicillium, the spores of Papulaspora anomala and Circinella muscae, and the vegetative cells of Micrococcus and Mycobacterium are more susceptible to UV radiation. All of the isolated microorganisms have been shown to be resistant to high vacuum. Their inactivation varied within the range of 2 to 16%, with an exception of Micrococcus cells (40%).

Air Microbiology↗
PubMedDate not supplied

[Optimal conditions for determing ATP of microbial origin].

Endogenous luminescence of the luciferin-luciferase extract from firely tails was studied in determing low concentrations of ATP. The optimum concentration of the the extract, corresponding to the minumum effect of endogenous luminescence, was found in the reaction medium. The solution of luciferin-luciferase was unstable at room temperature and upon dilution. The activity of luciferin-luciferse solutions did not change after freezing in liquid nitrogen with following thawing. The content of ATP was assayed in the cells of Sarcina flava disintegrated with ultrasound.

Adenosine Triphosphate↗
PubMedDate not supplied

[Collagenolytic enzymes synthesized by microorganisms].

The review uses data obtained by the authors and available in the literature to discuss microbial collagenolytic enzymes, widely employed in scientific research, biotechnology, and medicine. Collagenases differing in their structure and the specificity of their action on collagen fibrils were isolated from bacteria (including marine isolates), actinomycetes, and fungi. Collagenases produced by Clostridium histolyticum and Achromobacter iophagus are the best studied enzymes; both are metalloenzymes that contain Zn2+ in their active site and retain collagenolytic activity in the presence of Ca2+. Serine-type collagenolytic proteases were also found in microorganisms. These enzymes differ from "true" collagenases by the structure of their active site. Both serine proteases and metalloproteases with high collagenolytic activities were isolated from the culture liquids of Streptomyces and Actinomyces strains. The biosynthesis of collagenases is induced by the addition of various collagen-containing substrates to the cultivation medium.

Actinomyces↗