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Biomedical subjects

N K Kovalenko

Publications and source records attributed to N K Kovalenko.

At least 19 recordsLinked to original sources
PubMed2005

Elevation of the efficacy of antitumor vaccine prepared on the base of lectines from B. subtilis B-7025 upon its combined application with probiotics in vivo.

UNLABELLED: The aim of the work was to evaluate in vivo the possible enhancement of efficacy of antitumor vaccine prepared on the base of cytotoxic lectine from B. subtilis B-7025 by its combination with probiotic mixture of Enterococcus faecium K-50 and Saccharomyces cerevisiae 14K or their metabolic products. MATERIALS AND METHODS: Experiments were carried out on the models of solid sarcoma 37 (S37) and metastatic Lewis lung carcinoma (3LL). Efficacy of treatment was evaluated by parameters of tumor growth, median survival time of experimental animals and volume of metastases. RESULTS: We have shown that combined application of antitumor vaccine with pro-and/or prebiotic resulted in synergistic effect in the therapy S37-bearing mice, whilst in 3LL-bearing animals application of vaccine along with prebiotic inhibited metastasis by 2-2.5-fold compared to animals treated by vaccine only. CONCLUSION: Application of pre- and probiotics (E. faecium K-50 and S. cerevisiae) markedly elevates efficacy of antitumor vaccine in vivo.

Animals↗
PubMed1998

Incorporation of urea nitrogen into fecal protein and plasma protein amino acids in elderly human volunteers after ingestion of lactic acid bacteria.

Health effects of fermented milks have been associated with the metabolic activity of lactic acid bacteria in the gastrointestinal tract. It has been proposed that an increased excretion of urea nitrogen via microbial protein may decrease the workload on kidneys and liver. Therefore, a study was carried out in healthy elderly human subjects to investigate the incorporation of [15N2]urea nitrogen into plasma and fecal proteins and amino acids. Over a period of 10 d 13 healthy elderly subjects ingested daily a freeze-dried microbial preparation which contained different genera of lactic acid bacteria and is used to produce fermented milk products. One of the strains was originally isolated from stool samples of elderly people from the Caucasus region (Lactobacillus plantarum). No stimulation of fecal protein-nitrogen excretion and no increase in 15N-abundances in fecal protein was measured following the administration of the viable microbial preparation and a [15N2]urea bolus. Tentatively, it was concluded that this may have been caused by the inability of the microbial culture to survive the gastro-intestinal passage and (or) by the absence of additional fermentable carbohydrates in the diet as energy source for bacterial protein synthesis in the large intestine. However, using a highly sensitive GC-C-IRMS method we observed a significant incorporation of 15N into plasma protein amino acids. 15N-Enrichments in single amino acids were found according to their participation in transamination reactions. The slight enrichment of lysine which is not transaminated in mammalian tissues may indicate a microbial synthesis and absorption of bacterial lysine.

Aged↗
PubMed1992

[Antibiotic resistance of Lactobacillus strains].

One hundred and thirty six Lactobacillus strains isolated from poultry and 23 Lactobacillus strains isolated from long-living persons were tested for their antibiotic sensitivity. Occurrence of some type determinants of resistance to aminoglycoside antibiotics and tetracyclines in the Lactobacillus strains resistant to these antibiotics was studied. The majority of the strains from the both collections were resistant to aminoglycosides (73 and 79 per cent, respectively). The isolates from the poultry were characterized by multiple resistance. The isolates from the long-living persons were most frequently resistant to one of two antibiotics. All the tested Lactobacillus strains isolated from the long-living persons were sensitive to tetracyclines. The species composition of the isolates was different. The antibiotic-resistant strains were detected in all the species involved in the study. By hybridization of Lactobacillus colonies with the probes containing various genes of the resistance it was shown that in 14 per cent of the antibiotic-resistant strains belonging to Lactobacillus the antibiotic resistance was controlled by the genes homologous to resistance genes widely distributed in gramnegative organisms. This indicated a possible wide exchange and heterologous expression of the antibiotic resistance determinants between microorganisms of various taxonomic groups.

Aged↗
PubMed1979

[Lactic acid bacteria and streptococci of the human stomach normally and in pathological processes].

Lactic acid bacteria were either absent or present in negligent quantities in the stomach of apparently healthy man. But in case of various pathological processes in the stomach and duodenum lactic acid bacteria accumulated (up to a million cells per 1 ml of gastric contents). Under these conditions coccal forms sharply prevailed over the bacillary ones. In patients with chronic gastritis and peptic ulcer of the stomach the most frequent were Streptococcus faecalis and its variants; in oncological patients--Str. faecium, strains affiliated to Leuconostoc mesenteroides, and sometimes Str. durans.

Adult↗
PubMedDate not supplied

[The bacteriocinogenic and lysozyme-synthesizing activity of lactobacilli].

It was shown that lactic acid bacteria isolated from different sources produced along with lactic acid the bacteriocine substances. Strains producing bacteriocines were mainly isolated from digestive tract of people and calves. Bacteriogenic properties have been shown more frequently in the case of lactobacilli (7.8%) more rarely--in coccoid forms of lactic acid bacteria (4.5%). At the same time bacteriocine activity was higher in the case of Enterococcus and depended both on the strain type and cultivation conditions. Synthesis of bacteriocines started from the hours of phase of the culture growth and reached maximum at the beginning of stationary phase. The bacteriocine accumulation rate depended on composition of the growth medium.

Animals↗
PubMedDate not supplied

[The role of the carbohydrate composition of the glycocalyx in some species of lactobacilli in the manifestation of their adhesive properties].

Availability of certain monosaccharides in the composition of glycocalyx of lactic acid bacteria (Lactobacillus plantarum--strains 337D and 11/16; Streptococcus thermophilus--strains S1 (nonmucous race) and S5 (mucous race), Enterococcus faecium (K-50) has been investigated with the help of plant lectins with certain carbohydrate specificity labelled by colloid gold. All the microorganisms under investigation were characterized by the presence of N-acetyl-D-galactosamine and N-acetyl-D-glucosamine in rather insignificant amounts. Glycocalyx of lactic acid bacteria was also characterized by availability of essential amount of L-fructose and low amount of sialic acid (except for S. thermophilus S5 (mucous race). Presence of alpha-N-acetyl-D-galactosamine, alpha-D, beta-D-galactose, alpha-D-glucose, alpha-D-mannose in the composition of the lactic acid bacteria glycocalyx composition evidences for the additional role of these monosaccharides in the process of the microorganism adhesion on the human and animal intestine mucosa. It has been confirmed that availability of certain monosaccharides in the composition of surface glycopolymers of lactic acid bacteria was connected with adhesive properties of cells and their existence conditions.

Bacterial Adhesion↗
PubMedDate not supplied

[Use of PCR for the identification of representatives of Lactobacillus and Streptococcus].

REP- and ERIC-PCR genome analysis of lactic acid bacteria of genera Lactobacillus and Streptococcus have shown the presence of REP- and ERIC-repetitive sequences with high degree of homology. Amplification products which separation in agar gel results in formation of a specific fingerprint are obtained under REP- and ERIC-PCR. It is shown that REP- and ERIC-specific primers can be used for PCR identification of both enterobacteria and lactic acid bacteria isolated from different ecological niches.

DNA Fingerprinting↗
PubMedDate not supplied

[Searching for restriction endonucleases, finding out the heterogeneity of the 16S rRNA in some species of lactic acid bacteria].

The preliminary test of carbohydrates fermentation has been carried out to confirm a regular position for some lactic acid bacteria strains. Restriction cards have been compiled for Lactobacillus plantarum, L. delbrueckii and Streptococcus salivarius using Vector NTI program. A comparative analysis of the restriction cards has shown presence of unique sites of restriction endonucleases, which can be used for differentiation of the above-stated species.

Carbohydrate Metabolism↗
PubMedDate not supplied

[Probiotics based on live cultures of microorganisms].

The modern state of probiotic design and production was discussed in the survey. The worldwide data concerning types of probiotics and their use for restoration of resident microflora of hot-blooded animals and people were systematized. Much attention has been recently paid to the use of the natural preparations to maintain and regenerate the state of the resident microflora of animals and people. These preparations are known as probiotics. The term "probiotic" means microorganisms or substances which are capable to render sanitary effect on macroorganism. I. I. Mechnikov's concept on detoxifications of harmful substances formed in the digestive tract of men by probiotics is expounded. The modern concepts of the probiotics division into groups have been presented. Different kinds of industrial probiotics were considered. The mechanism of positive action of probiotics and their mutual relations with micro- and macroorganisms were provided. The scientific substantiation of new probiotic design was presented.

Animals↗
PubMedDate not supplied

[Design of primers to DNA of lactic acid bacteria].

Primers LP1-LP2 to the gene 16S rRNA have been developed, which permit to differentiate lactic acid bacteria: Lactobacillus plantarum, L. delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus. The strain-specific and species-specific differentiations are possible under different annealing temperature. Additional fragments, which are synthesized outside the framework of gene 16S rRNA reading, provide for the strain-specific type of differentiation, and the fragment F864 read in the gene 16S rRNA permits identifying L. plantarum.

DNA Primers↗
PubMedDate not supplied

[Screening of the strains of lactic acid bacteria possessing hypocholesterinemic activity and their practical use].

The strains of lactic acid bacteria (n = 139) belonging to Lactobacillus, Streptococcus, Enterococcus and Leuconostoc genera have been studied. It has been shown that neither of the strains used cholesterol as a source of carbon. Some strains (13.6%) hydrolyzed actively the conjugates of bile acids. The hydrolyzed activity displayed to a higher extent in anaerobic conditions on the medium with glucose. Hydrolase of conjugates of bile salts, which precipitated under acid value of pH and were excreted from the organism, was contained in 29% of 69 studied strains of lactic acid bacteria. Cholesterol is also removed from the organism under the same pH values that is confirmed by clinical tests of the product "Gerolakt Kislomolochny" (lactic-acid Gerolact).

Anaerobiosis↗
PubMedDate not supplied

[Determination of species belonging to the Lactobacillus genus with the use of RAPD-typing].

The numeric analysis of 14 strains of lactobacilli investigated by 57 phenotypical characteristics, has resulted in formation of three clusters: group L. delbrueckii, L. plantarum and the modular group formed by strains of various species. The API-testing, 16S rRNA sequencing and RAPD-typing with primers 5'-AGCAGCGTGG-3' and LP3-ST 5'-TGGTCCGAGC-3' have been carried out for several strains which position in a dendrogram did not correspond to their species diagnosis. The obtained data have allowed the reclassification of the strain L. delbrueckii subsp. bulgaricus B-1923T as L. plantarum B-1923T, L. agilis B-2603 as L. fermentum B-2603, L. amylophilus 30/4/(2) as L. plantarum 30/4/(2). Strain L. confusus 39T, identified by the phenotypical characteristics and data of API-testing as L. fermenturm, was reclassified on the basis of the phylogenetic analysis and RAPD-typing, as L. pentosus 39T.

Bacterial Typing Techniques↗
PubMedDate not supplied

[Adhesion of lactic acid bacteria to epithelium of different cavities of the human organism].

During investigation of adhesive properties of lactic acid bacteria it was found out that 11 strains adhered to buccal intestinal and vaginal epithelium of human. The highest adhesive activity was detected in enterococci (adhesive index 7.75-14.26), lower one--in streptococci (6.40-9.16). In lactobacilli adhesive properties manifested in different ways: Lactobacillus acidophilus strains adhered more often to buccal epithelium (2.58-4.60) and rarely--to intestinal and vaginal. L. plantarum manifested high adhesive activity (8.03 -9.69) to buccal epithelium and lower one--to the rest of epithelium types. Monosaccharide composition of glycocalix of 6 strains of lactic acid bacteria was studied to understand the adhesion mechanism. It was shown that surface structures of this microorganism interact with plant lectins, specific to certain monosaccharides.

Bacterial Adhesion↗
PubMedDate not supplied

[Antagonistic properties of bifidobacteria isolated from different natural sources].

Thirty (30) bifidobacterial strains were isolated from different natural sources (intestinal tract of human, cattle, insects, mice, dolphins, dairy products) are investigated. The belonging of all strains studied to genus Bifidobacterium was determined according to phenotype properties and PCR method. Antagonistic properties of the strains were studied on the media with glucose and some probiotics. The highest antagonistic activity was shown by strain grown on the medium with glucose (zones of growth inhibition were from 6.3 up to 25.3 mm), the lowest--on the media with inulin (0 - 18.3 mm). The activity of some bifidobacterial strains on media with lactulose and inulin can be considered as their inclusion to synbiotics.

Animals↗
PubMedDate not supplied

[Adhesive properties of lactic acid bacteria and methods of their investigation].

Current status of the question concerning the study of lactic acid bacteria adhesion process is presented in the review. Lactic acid bacteria colonization capacity allows them to form monolayers, to join the mucosal microbiota, to become a component of ecological barrier, which protects an organism from penetration of pathogens. The available methods of investigation of adhesive properties such as microbiological, light and electron microscopy, biophysical, mathematical and others are presented in detail. The works concerning lactic acid bacteria adhesines nature and factors that influence the exhibition of adhesion have been analyzed. Studies concerning the mechanisms responsible for attachment of cells of lactic acid bacteria to the surface of different types of epithelium and substances that are products of endothelium secretion are analyzed. Questions on adhesion specificity and factors that inhibit its exhibition are considered. The chart of current concept of the adhesive process and factors that reciprocally affect the exhibition of lactic acid bacteria adhesion properties is developed and presented by the authors.

Adhesins, Bacterial↗
PubMedDate not supplied

[Antibiotic sensitivity of bifidobacteria isolated from different natural sources].

Antibiotic sensitivity of 30 strains of bifidobacteria isolated from various ecologic sources has been investigated. All the studied strains of bifidobacteria were sensitive to nitrofurans, macrolides, linkosamides. Bifidobacteria strains isolated from people and farm animals displayed more frequently resistance to fusidine, cefasoline and doxycycline compared with the strains which were isolated from other natural sources. Most of the studied strains of bifidobacteria were resistant to oxacylline. Representatives of the species Bifidobacterium liberorum, B. catenulatum, B. bifidum, B. adolescentis, B. breve, B. ruminale and B. globosum were most resistant to the studied antibiotics.

Animals↗