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Biomedical subjects

L V Didenko

Publications and source records attributed to L V Didenko.

24 records · Page 2Linked to original sources
PubMedDate not supplied

[Biofilm formation by different strains of Salmonella typhimurium in artificial systems].

The ability of 14 different strains of Salmonella typhimurium to biofilm formation depending on genotype and culture conditions was investigated in artificial systems: in 96-well plastic microtitre plates, plastic and glass tubes, plastic Petri dishes and on microscope glasses. Quantitative biofilm growth was monitored by using an assay based on crystal violet staining, while planctonic growth in the same cultures was monitored by absorbance in iEMS Reader MF, and qualitatively--by digital photo and visually. Optimal rate between growth and biofilm indications for all strains was determined at initial cell concentration 10(6-7) KOE/ml and culture incubation at t degrees 28 degrees C. The nutrient content of the medium significantly influenced the quantity of produced biofilm. The nutrient broth LB without NaCl was more effective in promoting biofilm formation, than LB itself. The least quantity of biofilm was formed in water. The genotype of the strains also critically influenced the quantity of produced biofilm. Nonmotile mutants cells had reduced ability to form biofilm. RpoS mutant cells produced significantly less biofilm as compared with cells of isogenic parent strains. The chemical content of plastic and glass also influenced biofilm formation.

Bacterial Proteins↗
PubMedDate not supplied

[Formation of biofilms as an example of the social behavior of bacteria].

This paper is a brief review of data on bacterial biofilms that occur inside and outside of host organisms. Such biofilms are of great ecological and clinical importance. The role of interspecies communications in the development of bacterial biofilms and infectious diseases is particularly emphasized. Considerable attention is given to the electron microscopic study of biofilms formed by Salmonella typhimurium cells incubated as a broth culture in microtubes without aeration. Bacterial samples taken from the biofilm and planktonic culture grown in the same microtube were comparatively investigated by transmission electron microscopy.

Bacteria↗
PubMedDate not supplied

[A novel method of concentrating bacterial suspensions for transmission electron microscopy].

Presents a new method for making preparations of bacteria and their unculturable forms from suspensions with low concentrations of cells, from 1 x 108 to 1 x 104 per ml. to be examined under transmission electron microscope. The novelty of the method consists in the technique of concentrating bacteria by making a colloid solution consisting of bovine serum albumin and polyethyleneglycol. Associations of protein molecules, polyethyleneglycol, and bacteria, forming in the solution, are sedimented by centrifugation after 48-hour incubation at 4 degrees C. The solidity of the resultant macroscopic sediment is sufficient for studying the cells contained in it under transmission electron microscope.

Bacteriological Techniques↗
PubMedDate not supplied

[Dormant forms of Yersinia pseudotuberculosis during interaction with green algae and their exometabolites (population dynamics and ultrastructure)].

The dynamics of the transition of Y.pseudotuberculosis to the latent (noncultivable) state in sterile soil extraction and in soil extraction, containing Scenedesmus algae or their exometabolites, was evaluated by the bacteriological method and with the use of polymerase chain reaction. The formation of Y.pseudotuberculosis latent forms achieved its highest rate under the action of algal exometabolites (on day 11), while in the presence of algal cells such formation was delayed to 3-5 months. The partial reversion of Y.pseudotuberculosis nonculativable forms to vegetative, bacteriologically detectable forms occurred under the action of fetal serum, as well as live or killed infusoria. Transmission electron microscopy demonstrated that noncultivable Y.pseudotuberculosis had a round form, diminished cell size, denser cytoplasm and enlarged cytoplasmic space. The reversible transition of bacteria to the latent state is regarded as their adaptation to unfavorable factors during their existence in soils and water reservoirs.

Adaptation, Physiological↗
PubMedDate not supplied

[Detoxicating function of the placenta of childbearing women from ecologically unfavorable regions of the Ukraine].

A study of placental detoxifying activity was undertaken using as the investigated indices glutathione transferase and glutathione reductase activities and total amount of SH-groups and those of low-molecular weight thiols. Malonic dialdehyde content was used as a measure of lipid peroxidation. The placental samples were obtained in several regions of the Ukraine judged either "clean", chemically polluted or radioactively contaminated. In the samples from the "clean" region glutathione transferase and glutathione reductase activities as well as the total amount of SH-groups were higher than corresponding indices in ecologically unfavorable regions of the Ukraine. At radioactively heavily exposed women low glutathoione transferase activity combined with low content of SH-groups and pronounced increase of malonic dialdehyde. In the regions with the lower summary effective equivalent annual expositional doses the indices of placental glutathione status are more close to those characteristic for placenta from "clean" regions. The consequences of the more intensive but short exposure characteristic for the women evacuated from Pripyat on the second day after catastrophe were less manifest in the indices of the glutathione status. A decrease of glutathione transferase activity at chemically exposed women was in the range of the lowest values obtained for heavily radioactively exposed ones but differ by higher content of total SH-groups and low molecular weight thiols. The glutathione transferase activity of cytosol from the samples of chemically exposed women increased in vitro after their treatment with the reducing agent. More probable the different mechanisms underlie the similar reduce of glutahtione transferase activity in radioactively contaminated and chemically polluted regions of the Ukraine. The decreased activity of glutathione transferase activity in placenta correlated with the increased frequency of complications during the pregnancy and the delivery and with the worsening status of newborns.

Female↗