Discovery of a novel bacteriocin is always an event in sciences, since cultivation of most bacterial species is a general problem in microbiology. This statement is reflected by the fact that number of bacteriocins is smaller for tenfold comparing to known antimicrobial peptides. We cultivated Enterococcus faecium on simplified medium to reduce amount of purification steps. This approach allows to purify the novel heavy weight bacteriocin produced by E. faecium ICIS 7. The novelty of this bacteriocin, named enterocin-7, was confirmed by N-terminal sequencing and by comparing the structural-functional properties with available data. Purified enterocin-7 is characterized by a sequence of amino acid residues having no homology in UniProt/SwissProt/TrEMBL databases: NH2 - Asp - Ala - His - Leu - Ser - Glu - Val - Ala - Glu - Arg - Phe - Glu - Asp - Leu - Gly. Isolated thermostable protein has a molecular mass of 65 kDa, which allows it to be classified into class III in bacteriocin classification schemes. Enterocin-7 displayed a broad spectrum of activity against some Gram-positive and Gram-negative microorganisms. Fluorescent microscopy and spectroscopy showed the permeabilizing mechanism of the action of enterocin-7, which is realized within a few minutes.
The novel BLIS from E. faecium ICIS 8 was characterized by a unique primary peptide sequence and exerted bactericidal activity against L. monocytogenes and E. coli by disrupting membrane integrity.
The mechanism of E. coli translocation after its intragastral administration was studied in rats with acute pancreatitis. Bacterial dissemination into visceral organs was shown. Therapy with probiotic sporobacterin was more effective than antibiotic (cefaxon) therapy. Contamination of the viscera with Escherichia was notably decreased.
A psychrotolerant facultative anaerobe, strain SKBGT, was isolated from the bottom sediments of the cold mineral spring Buxichen (Buryatia, Russia). Gram-positive non-motile cocci with a diameter of 1.75–2.5 µm were observed singly or in long chains. Cells grew in the temperature range from ̶ 5–35 °C. Growth was observed within the pH range of 7.0–9.5, with the optimum growth at pH 7.6 and at a NaCl concentration from 0–1.0 % (optimum 0.1 % (w/v)). Strain SKBGT was a chemoorganoheterotroph that used sugars and some organic acids as substrates. The predominant fatty acids in cell walls were С16:1ω9, С18:1ω9, and С16 : 0. The 16S rRNA gene sequence of strain SKBGT shared high similarity (>99 %) with those of the type strains of the genus
Trichococcus
. Digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain SKBGT and
Trichococcus shcherbakoviae
ArtT (=DSM 107162T=VKM B-3260T) were 70.1 and 95.4 %, respectively. The genomic DNA G+C content of strain SKBGT was 47.1 mol%. Compared with the type strain of
T. shcherbakoviae
, the new strain was characterized by a temperature optimum for growth (10 °C) significantly lower than that of
T. shcherbakoviae
DSM 107162T (20–30 °C). Based on phenotypic and genomic characteristics, the isolate SKBGT was classified as
T. shcherbakoviae
subsp. psychrophilus subsp. nov. The type strain is SKBGT (=VKM B-3241Т=JCM 33326T).
The range of antilysozyme activity (the sign of persistence) of Escheriehia coli clones from subpopulations isolated from natural and artificial ecosystems is established. It is shown that heterogeneity of the microorganism population reflects the ecological status of its habitat. Therefore, it can be used as a test-indicator in biomonitoring and as an index in the standardization of eubiotics.
Key Words: E. coli; eubiotic; population analysis; persistenceThe population method has been widely used in epidemiology for prediction of epidemics [1], in experimental research for evaluation of persistence and elimination of the causative agent [5], and in environmental studies [6].The factors of microorganism persistence, which reflect the flexibility of the adaptation mechanisms of a given population, may be employed to solve ecological, hygienic, and biotechnological problems [2].The aim of this study was to explore the possibility of using the population method for assessing the habitat of microorganisms and for standardization of cultures used for the production of eubiotics.
MATERIALS AND METHODSE. coli was selected because it is an ubiquitous microorganism with a high adaptive potential. Model subpopulations and subpopulations isolated from natural (human body and open water reservoir) and from man-made (sewers) ecosystems were used. All Department of Microorganism Persistence, Institute of Ecology and Genetics of Microorganisms, Ural Division of the Russian Academy -of Sciences, Orenburg escherichia isolated from different econiches possessed typical biological characteristics. The enterobacteria were isolated from human intestine with due consideration for their intracellular parasitism [4]. E. coli serogroups 0-20, O-111, 0-75, O-128, and O-114 were isolated from patients with enteric infections. Typical E. coli whose serotype could not be determined with the standard diagnostic kit were isolated from normal subjects, from the Ural river at the site of water intake (clean zone) and waste disposal (contaminated zone), and from sewers.E. coli (strain M-17) contained in the preparation Colibacterin were employed as a model microorganism.The subpopulations were cloned by serial dilutions and inoculations, so that no more than 100 colonies grew in each dish. Population analysis of the antilysozyme activity (ALA) of E. coli was performed by the method of imprints [8]. Antilysozyme activity was assayed as described elsewhere [3].
RESULTSIn the subpopulation which was isolated from patients and consisted of E. coli of different sero-
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.