Natural bacterial isolates as an inexhaustible source of new bacteriocins.

Microorganisms isolated from various traditionally fermented food products prepared in households without commercial starter cultures are designated as natural isolates. In addition, this term is also used for microorganisms collected from various natural habitats or products (silage, soil, manure, plant and animal material, etc.) that do not contain any commercial starters or bacterial formulations.

Diversity of non-starter lactic acid bacteria in autochthonous dairy products from Western Balkan Countries - Technological and probiotic properties.

The aim of this review was to summarize the data regarding diversity of non-starter lactic acid bacteria (NSLAB) isolated from various artisanal dairy products manufactured in Western Balkan Countries. The dairy products examined were manufactured from raw cow's, sheep's or goat's milk or mixed milk, in the traditional way without the addition of commercial starter cultures. Dairy products such as white brined cheese, fresh cheese, hard cheese, yogurt, sour cream and kajmak were sampled in the households of Serbia, Croatia, Slovenia, Bosnia and Herzegovina, Montenegro, and North Macedonia.

Characterisation of the yeast and mould biota in traditional white pickled cheeses by culture-dependent and independent molecular techniques.

Artisanal white pickled cheese of Western Serbia is a product of complex microbial community which detection by culture-dependent method only is hampered by its limitations. Thus, in the present study, we used a culture-independent, semi-quantitative technique based on construction of an internal transcribed spacer (ITS)-clone library from metagenomic DNA. This approach, based on direct DNA extraction followed by amplification of fungal internal transcribed regions (ITS) cloned into plasmid and restricted by endonucleases, revealed greater species richness in analysed cheeses and their by-products (17 species in total) compared to the more commonly used techniques of the culture-dependent method (8 species) and LSU-DGGE (10 species).

Evaluation of probiotic potential of yeasts isolated from traditional cheeses manufactured in Serbia and Croatia.

Aim: The aim of this study was to investigate the in vitro probiotic potential of dairy yeast isolates from artisanal cheeses manufactured in Serbia and Croatia.

Materials And Methods: Twelve yeast strains isolated from artisanal fresh soft and white brined cheeses manufactured in Serbia and Croatia were used in the study. Survival in chemically-simulated gastrointestinal conditions, adherence to epithelial intestinal cells and proliferation of gut-associated lymphoid tissue (GALT) cells were evaluated.

Isolation and Characterisation of Bacteriocin and Aggregation-Promoting Factor Production in ssp. BGBM50 Strain.

ssp. BGBM50, a producer of lactococcin G and aggregation-promoting factor, was isolated from selected lactic acid bacteria taken from semi-hard cheese traditionally produced in the village Žanjic, Montenegro. Strain BGBM50 harbours a number of plasmids of different sizes.

Defining the structure and receptor binding domain of the leaderless bacteriocin LsbB.

LsbB is a class II leaderless lactococcal bacteriocin of 30 amino acids. In the present work, the structure and function relationship of LsbB was assessed. Structure determination by NMR spectroscopy showed that LsbB has an N-terminal α-helix, whereas the C-terminal of the molecule remains unstructured.

Characterization of lactic acid bacteria isolated from artisanal Travnik young cheeses, sweet creams and sweet kajmaks over four seasons.

The aim of this study was to investigate the composition of lactic acid bacteria (LAB) in autochthonous young cheeses, sweet creams and sweet kajmaks produced in the Vlašić mountain region of central Bosnia and Herzegovina near the town of Travnik over a four season period. These three products were made from cow's milk by a traditional method without the addition of a starter culture. Preliminary characterization with phenotype-based assays and identification using rep-PCR with a (GTG)5 primer and 16S rDNA sequence analysis were undertaken for 460 LAB isolates obtained from all the examined samples.

A Zn-dependent metallopeptidase is responsible for sensitivity to LsbB, a class II leaderless bacteriocin of Lactococcus lactis subsp. lactis BGMN1-5.

Lactococcus lactis subsp. lactis BGMN1-5 produces a leaderless class II bacteriocin called LsbB. To identify the receptor for LsbB, a cosmid library of the LsbB-sensitive strain BGMN1-596 was constructed.

Evaluation of lactic acid bacteria and yeast diversity in traditional white pickled and fresh soft cheeses from the mountain regions of Serbia and lowland regions of Croatia.

The goal of this study was the characterisation of indigenous lactic acid bacteria (LAB) and yeasts isolated from nine white pickled (BG) and nine fresh soft (ZG) artisanal cheeses collected in Serbia and Croatia. While LAB were present in all of the cheeses collected, yeasts were found in all BG cheeses but only in three ZG cheese samples. High LAB and yeast species diversity was determined (average H'(L)=0.

Interaction of Lactobacillus fermentum BGHI14 with rat colonic mucosa: implications for colitis induction.

The present study was carried out to test the colonic mucosal response of rats to oral supplementation with Lactobacillus fermentum BGHI14 and to correlate the tissue reaction to trinitrobenzenesulfonate (TNBS)-induced colitis with mucosal barrier alterations caused by bacterial ingestion. An immune cell-mediated reaction of healthy colonic tissue was noticed after bacterial feeding. After prolonged bacterial treatment, the observed reaction had retreated to normality, but the mRNA levels of proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor alpha (TNF-α) remained elevated.

The clinical isolate Pseudomonas aeruginosa MMA83 carries two copies of the blaNDM-1 gene in a novel genetic context.

The genetic context of the blaNDM-1 gene in the genome of Pseudomonas aeruginosa MMA83 was investigated. Sequencing of the cosmid selected for the blaNDM-1 gene revealed the presence of two blaNDM-1 copies in the genome of P. aeruginosa MMA83 in a unique genetic environment.

Technological and probiotic potential of BGRA43 a natural isolate of Lactobacillus helveticus.

Lactobacillus helveticus BGRA43 is a human intestinal isolate showing antimicrobial activity, amongst others, against Yersinia enterocolitica, Shigella sonnei, Shigella flexneri, and Streptococcus pneumoniae. BGRA43 produces PrtH proteinase with proteolytic activity on both casein and β-lactoglobulin (BLG). BGRA43 is able to reduce the allergenicity of BLG.

Genotypic diversity and virulent factors of Staphylococcus epidermidis isolated from human breast milk.

Staphylococcus epidermidis strains were isolated from the expressed human breast milk (EHM) of 14 healthy donor mothers. Genetic diversity was evaluated using RAPD-PCR REP-PCR and pulse-field gel electrophoresis (PFGE). PFGE allowed the best discrimination of the isolates, since it provided for the greatest diversity of the analyzed genomes.

The cmbT gene encodes a novel major facilitator multidrug resistance transporter in Lactococcus lactis.

Functional characterization of the multidrug resistance CmbT transporter was performed in Lactococcus lactis. The cmbT gene is predicted to encode an efflux protein homologous to the multidrug resistance major facilitator superfamily. The cmbT gene (1377 bp) was cloned and overexpressed in L.

Characterisation of the exopolysaccharide (EPS)-producing Lactobacillus paraplantarum BGCG11 and its non-EPS producing derivative strains as potential probiotics.

Traditional fermented foods are the best source for the isolation of strains with specific traits to act as functional starters and to keep the biodiversity of the culture collections. Besides, these strains could be used in the formulation of foods claimed to promote health benefits, i.e.

Probiotic features of two oral Lactobacillus isolates.

In this study, we checked lactobacilli strains of human origin for their potential as probiotic. Samples were collected from oral mucosa of 16 healthy individuals, out of which twenty isolates were obtained and two of them were selected and identified as Lactobacillus plantarum (G1) and L. casei (G3).

Cloning and expression of a novel lactococcal aggregation factor from Lactococcus lactis subsp. lactis BGKP1.

Background: Aggregation may play a main role in the adhesion of bacteria to the gastrointestinal epithelium and their colonization ability, as well as in probiotic effects through co-aggregation with intestinal pathogens and their subsequent removal. The aggregation phenomenon in lactococci is directly associated with the sex factor and lactose plasmid co-integration event or duplication of the cell wall spanning (CWS) domain of PrtP proteinase.

Results: Lactococcus lactis subsp.

Emergence of NDM-1 metallo-β-lactamase in Pseudomonas aeruginosa clinical isolates from Serbia.

This work reports, for the first time, the presence of New Delhi metallo-β-lactamase 1 (NDM-1) in Pseudomonas aeruginosa. Moreover, this is the first report of the NDM-1 presence in the Balkan region. Cosmid gene libraries of carbapenem-nonsusceptible Pseudomonas aeruginosa clinical isolates MMA83 and MMA533 were screened for the presence of metallo-β-lactamases.

Inducible expression of choline sulfatase and its regulator BetR in Pseudomonas sp. ATCC19151.

Pseudomonas sp. strain ATCC19151 is a natural isolate from sewage with the ability to degrade detergents. Genes encoding potential choline sulfatase (betC), substrate-binding ABC transporter protein (betD), sulfate transporter (betE), and divergent putative transcriptional regulator (betR) were cloned and characterized from strain ATCC19151.

Regulation of the sdsA alkyl sulfatase of Pseudomonas sp. ATCC19151 and its involvement in degradation of anionic surfactants.

Aims: The presented study was aimed to reveal transcriptional regulation of genes involved in SDS degradation (sdsA and sdsB) in Pseudomonas sp. ATCC19151. In addition, the ability of Pseudomonas sp.

Construction of a new shuttle vector and its use for cloning and expression of two plasmid-encoded bacteriocins from Lactobacillus paracasei subsp. paracasei BGSJ2-8.

A new shuttle-cloning vector, pA13, was constructed and successfully introduced into Escherichia coli, Lactobacillus and Lactococcus strains. It showed high segregational and structural stability in all three hosts. The natural plasmid pSJ2-8 from L.

The presence of prtP proteinase gene in natural isolate Lactobacillus plantarum BGSJ3-18.

Aims: The study of proteolytic activity and examination of proteinase gene region organization in proteolytically active Lactobacillus plantarum strains from different natural sources.

Methods And Results: A set of 37 lactobacilli was distinguished by using multiplex PCR assay. Results showed that 34 strains were Lact.

Variation in specificity of the PrtP extracellular proteinases in Lactococcus lactis and Lactobacillus paracasei subsp. paracasei.

Comparison of cell-wall-bound extracellular proteinases (CEPs) from Lactobacillus paracasei (LBP) ssp. paracasei natural isolates BGHN14, BGAR75 and BGAR76 with Lactococcus lactis (LCL) ssp. cremoris Wg2, in their action on alpha(S1)-, beta- and kappa-casein was done.