Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “BACTERIOCINS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed2005

Growth and bacteriocin production kinetics of Leuconostoc mesenteroides E131.

AIMS: The aim of this study was to investigate the effect of pH, temperature, sodium chloride, type and level of sugar used in fermented sausages, on the occurrence and the concentration of the maximum bacteriocin activity, in order to optimize the bacteriocin synthesis during the growth cycle of Leuconostoc mesenteroides E131. METHODS AND RESULTS: In order to study the effect of the environmental factors on growth and bacteriocin production of Leuc. mesenteroides E131 fermentations were carried out in fermentor as well as in flasks. Mathematical equations were used to describe the kinetic parameters of the strain. When the micro-organism was grown in lower pH value (5.5) than optimum for growth (pH 6.5) the bacteriocin production was enhanced. On the contrary, bacteriocin production was favoured when the micro-organism was grown at temperatures close to the optimum for growth (25 degrees C). Finally, the level and the type of the sugar used as carbon source affected both growth and bacteriocin production with glucose being better source for biomass production and fructose more suitable for bacteriocin production. CONCLUSIONS: Leuconostoc mesenteroides E131 has a potential use as protective culture or its bacteriocin as protective agent in combination with another starter culture in fermented meats. SIGNIFICANCE AND IMPACT OF THE STUDY: Better understanding of the influence of environmental factors, such as pH, temperature and carbon source on the kinetic behaviour of Leuc. mesenteroides E131.

Antibiosis↗
PubMed1997

Bacteriocin production and sensitivity among coaggregating and noncoaggregating oral streptococci.

Twenty-one oral Streptococcus isolates of known interbacterial coaggregation groups were tested against one another (as both producers and indicators) to detect bacteriocin-like inhibitory activity. In agar-based antagonism tests, seven strains produced small inhibitory zones (< or = 3 mm diameter) but in liquid medium, only strain Streptococcus gordonii DL1 (Challis) produced a detectable antibacterial action (bacteriocin STH1). Five strains were sensitive to bacteriocin STH1, but neither the production of nor the sensitivity to any of the antagonistic agents correlated with coaggregation groupings. Four strains (C219, 903, 118 and Wicky) developed stable resistance in response to the bacteriocin, whereas one isolate (strain 34) remained sensitive following repeated bacteriocin exposure. With one exception (strain 903), bacteriocin STH1-sensitive strains were competent for genetic transformation, but not all competent strains were bacteriocin-sensitive. Bacteriocin-resistant derivatives of transformable strains exhibited decreased competence (80-90% reduction) compared with their parent strains.

Actinomyces↗
PubMed1978

Bacteriocin-like substances produced by Rhizobium japonicum and other slow-growing rhizobia.

Bacteriocin-like substances were commonly produced by slow-growing Rhizobium japonicum and cowpea rhizobia on an L-arabinose medium. Antagonism between strains of R. japonicum was not detected in vitro; however, such strains were often sensitive to some bacteriocins produced by cowpea rhizobia. Inhibitory zones (2 to 8 mm from colony margins), produced by 58 of 66 R. japonicum test strains, were reproducibly detected with Corynebacterium nebraskense as an indicator. Quantitative production was not related to symbiotic properties of effective strains, since nine noninfective strains and one ineffective strain produced bacteriocin. Eight R. japonicum strains that did not produce bacteriocin nevertheless formed effective nodules on soybeans. R. japonicum strains that produced bacteriocin in vitro had no antagonistic effect on nonproducer strains during soybean nodulation. Under controlled conditions, a nonproducer (3I1b135) predominated over a bacteriocin producer (3I1b6) when inoculated at 1:1 and 1:9 ratios. Depending on the particular ratio, up to 38% of the total nodules formed were infected with mixed combinations. The bacteriocin(s) had a restricted host range and antibiotic-like properties which included the ability to be dialyzed and resistance to heat (75 to 80 degrees C, 30 min), Pronase, proteinase K, trypsin, ribonuclease, and deoxyribonuclease. R. japonicum strains representing genetic, serological, cultural, and geographic diversity were differentiated into three groups on the basis of bacteriocin production.

Animals↗
PubMed1990

Plasmid-associated bacteriocin production by a strain of Carnobacterium piscicola from meat.

Carnobacterium piscicola LV17 isolated from vacuum-packed meat produces bacteriocin(s) that is active against closely related lactic acid bacteria, Enterococcus spp., and a strain of Listeria monocytogenes but not against gram-negative bacteria. The bacteriocin has a bactericidal mode of action, is heat resistant, and is stable over a wide range of pH but is inactivated by proteolytic enzymes. Sensitive and resistant cells were shown to adsorb the bacteriocin, but cell death depended on contact of the bacteriocin with the cell membrane. Bacteriocin production is detected early in the growth cycle of the organism in APT broth, but it is not produced in APT broth adjusted to pH 5.5. Bacteriocin production and resistance to the bacteriocin produced are associated with two plasmids of 40 and 49 megadaltons. The possibility that two bacteriocins are produced is indicated because the inhibitory substances of the mutant strains containing either the 40- or 49-megadalton plasmids have different antimicrobial spectra.

Bacteriocins↗
PubMed1997

Interactions of nisin and pediocin PA-1 with closely related lactic acid bacteria that manifest over 100-fold differences in bacteriocin sensitivity.

The natural variation in the susceptibilities of gram-positive bacteria towards the bacteriocins nisin and pediocin PA-1 is considerable. This study addresses the factors associated with this variability for closely related lactic acid bacteria. We compared two sets of nonbacteriocinogenic strains for which the MICs of nisin and pediocin PA-1 differed 100- to 1,000-fold: Lactobacillus sake DSM20017 and L. sake DSM20497 and Pediococcus dextrinicus and Pediococcus pentosaccus. Strikingly, the bacteriocin-sensitive and -insensitive strains showed a similar concentration-dependent dissipation of their membrane potential (delta psi) after exposure to these bacteriocins. The bacteriocin-induced dissipation of delta psi below the MICs for the insensitive strains did not coincide with a reduction of intracellular ATP pools and glycolytic rates. This was not observed with the sensitive strains. Analysis of membrane lipid properties revealed minor differences in the phospho- and glycolipid compositions of both sets of strains. The interactions of the bacteriocins with strain-specific lipids were not significantly different in a lipid monolayer assay. Further lipid analysis revealed higher in situ membrane fluidity of the bacteriocin-sensitive Pediococcus strain compared with that for the insensitive strain, but the opposite was found for the L. sake strains. Our results provide evidence that the association of bacteriocins with the cell membrane and their subsequent insertion take place in a similar way for cells that have a high or a low natural tolerance towards bacteriocins. For insensitive strains, overall membrane constitution rather than mere membrane fluidity may preclude the formation of pores with sufficient diameters and lifetimes to ultimately cause cell death.

Adenosine Triphosphate↗
PubMed2005

Combined effect of high-pressure treatments and bacteriocin-producing lactic acid bacteria on inactivation of Escherichia coli O157:H7 in raw-milk cheese.

The effect of high-pressure (HP) treatments combined with bacteriocins of lactic acid bacteria (LAB) produced in situ on the survival of Escherichia coli O157:H7 in cheese was investigated. Cheeses were manufactured from raw milk inoculated with E. coli O157:H7 at approximately 10(5) CFU/ml. Seven different bacteriocin-producing LAB were added at approximately 10(6) CFU/ml as adjuncts to the starter. Cheeses were pressurized on day 2 or 50 at 300 MPa for 10 min or 500 MPa for 5 min, at 10 degrees C in both cases. After 60 days, E. coli O157:H7 counts in cheeses manufactured without bacteriocin-producing LAB and not pressurized were 5.1 log CFU/g. A higher inactivation of E. coli O157:H7 was achieved in cheeses without bacteriocin-producing LAB when 300 MPa was applied on day 50 (3.8-log-unit reduction) than if applied on day 2 (1.3-log-unit reduction). Application of 500 MPa eliminated E. coli O157:H7 in 60-day-old cheeses. Cheeses made with bacteriocin-producing LAB and not pressurized showed a slight reduction of the pathogen. Pressurization at 300 MPa on day 2 and addition of lacticin 481-, nisin A-, bacteriocin TAB 57-, or enterocin AS-48-producing LAB were synergistic and reduced E. coli O157:H7 counts to levels below 2 log units in 60-day-old cheeses. Pressurization at 300 MPa on day 50 and addition of nisin A-, bacteriocin TAB 57-, enterocin I-, or enterocin AS-48-producing LAB completely inactivated E. coli O157:H7 in 60-day-old cheeses. The application of reduced pressures combined with bacteriocin-producing LAB is a feasible procedure to improve cheese safety.

Animals↗
PubMed1984

Mode of inhibitory action of a bacteriocin produced by Streptococcus mutans C3603.

The basis for the lethal activity of a bacteriocin produced by Streptococcus mutans C3603 (serotype c) was studied. Bacteriocin C3603 was found to adsorb to cells of representative strains of the seven serotypes of S. mutans. S. mutans BHT (serotype b) was used to study the adsorption and the lethal properties of bacteriocin C3603. The adsorption of bacteriocin to cells of S. mutans BHT was inhibited by treatment of cells with protease and beta-glucosidase and by such ligands as poly-L-lysine, poly-L-arginine, L-aspartic acid, L-glutamic acid, glutathione, oxidized glutathione, poly-L-aspartic acid, and poly-L-glutamic acid. The adsorption to cells was also inhibited by oligosaccharides and glucosamine. Mixtures of anionic and cationic amino acids or polyamino acids did not greatly enhance or antagonize the inhibition of adsorption of bacteriocin C3603 to cells. Sodium hydroxide extracts of cell walls and cell wall-membranes contained carbohydrates and proteins; however, only proteins were found to bind to bacteriocin or to a bacteriocin affinity column. The sodium hydroxide extracts contained about 35 protein bands as determined by sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis. Bacteriocin C3603 was found to immediately inhibit the synthesis of proteins, DNA, and RNA of cells and to slowly release DNA from cells of S. mutans BHT.

Adsorption↗
PubMed1985

Typing of Pseudomonas cepacia by bacteriocin susceptibility and production.

The significance of Pseudomonas cepacia as an opportunistic pathogen in immunocompromised patients has become increasingly recognized. Particularly disturbing is its increased incidence, reported by several North American centers, in respiratory tract cultures from patients with cystic fibrosis. Epidemiological studies of P. cepacia have been hampered by a lack of typing methods. In this paper we report the development of a typing scheme based on bacteriocin production and susceptibility. For bacteriocin production, test isolates of P. cepacia were rapidly applied to the surfaces of agar plates with a multiple inoculator. After incubation of these test isolates for 5.5 h and their exposure to chloroform, indicator strains were applied in agar overlays without prior removal of the test strain growth. After 18 h of incubation, inhibition zones caused by bacteriocin activity were recognized. A similar procedure was used to examine the bacteriocin susceptibility of the test strain. The bacteriocin type of the test strain was defined based on its bacteriocin production as judged by zones of inhibition against a set of eight indicator strains and by susceptibility or resistance of the test strain to bacteriocin produced by six producer strains. Of 373 strains of P. cepacia, 95.2% were typed into a total of 44 type combinations. Bacteriocin typing provided a suitable procedure for epidemiological studies of colonization or infection by P. cepacia. The technique described in this paper was simple to perform, gave a result within 24 h, provided good strain discrimination, and was suitable for clinical, environmental, and phytopathogenic strains.

Bacteriocins↗
PubMed1980

Sensitivity of some Erwinia carotovora serogroups to macromolecular bacteriocins.

Representative strains from each of 18 Erwinia carotovora serogroups were tested for bacteriocin activity. Eight bacteriocin producing strains were found and the bacteriocins partially purified by ammonium sulfate fractionation and high-speed centrifugation. Bacteriocins from all eight strains were morphologically similar to bacteriophage tails. Specific absorption of bacteriocins from one of the antagonistic strains to sensitive bacterial cells was demonstrated with electron microscopy. In four of the serogroups tested each strain was sensitive to only one or two of the bacteriocins while in other serogroups sensitivity varied. Strains of both E. carotovora var. atroseptica and E. carotovora var. carotovora were sensitive to the same bacteriocins, but the two serogroups of var. atroseptica could be differentiated from each other on the basis of sensitivity to one bacteriocin.

Bacteriocins↗
PubMed1982

Bacteriocin production by Pseudomonas syringae PsW-1 in plant tissue.

The production and activity of syringacin W-1, a particulate bacteriocin made by Pseudomonas syringae PsW-1, was studied in plant tissue. The bacteriocin is rod shaped, approximately 20 nm wide and 75 nm long, and composed of an outer sheath and inner core. Both the producing strain, PsW-1, and a sensitive strain, 16, grew within red kidney bean stems. Strains PsW-1 and 16, or mutants derived from them, were injected into bean stems singly or in mixtures. All singly inoculated strains grew well. However, when the bacteriocin-producing strain was co-inoculated with the sensitive strain, the latter grew poorly, if at all. This was not due to competition for available nutrients, since the sensitive strain grew as well in the presence of a bacteriocin-nonproducing mutant as it did alone. Also, a bacteriocin-resistant mutant grew as well in the presence of a bacteriocin-nonproducing mutant as it did alone. Also, a bacteriocin-resistant mutant grew as well in the presence of the producing strain as it did alone. Bacteriocin activity and particles were recovered from infected plant tissue.

Bacteriocins↗
PubMed1981

Bacteriocin (marcescin) typing of clinically isolated Serratia marcescens.

A study of bacteriocin (marcescin) typing was carried out by an agar cross streaking method (without any induction reagent) with 654 strains of Serratia marcescens recently isolated from clinical materials in Nagasaki University Hospital. In a complete checker board experiment with 80 strains on bacteriocin production and sensitivity, 43 strains (54%) were productive, 74 (93%) were sensitive and 4 (5%) were negative. Immunity was confirmed in all strains. Eight out of 80 strains of Serratia marcescens were selected as indicators in order to achieve the best differentiation of strains in bacteriocin typing, and 654 strains were classified into 30 types by bacteriocin production typing and into 49 types by bacteriocin sensitivity typing; the former showed more stable results than the latter in reproducibility. Bacteriocins produced by this method were considered to be high molecular, phage tail-like group A bacteriocins reported by Prinsloo (1966). Bacteriocin production typing was more useful for classification and subdivision of strains than serotyping (0-group).

Bacteriocins↗
PubMed1999

Identification and characterization of two bacteriocin-producing bacteria isolated from garlic and ginger root.

Two bacteriocin-producing bacterial strains were isolated from garlic and ginger root by the agar overlay method. The bacteria were identified by 16S rRNA sequence analyses and fermentation patterns as Leuconostoc mesenteroides (garlic isolate) and Lactococcus lactis (ginger isolate). The bacteriocins were assigned the names leucocin BC2 and lactocin GI3, respectively. Physiochemical properties and antimicrobial spectra of the bacteriocins were determined by the spot-on-lawn method. Both bacteriocins were inhibited by proteolytic enzymes. Leucocin BC2 exhibited a narrow antimicrobial spectrum, inhibiting only Bacillus, Enterococcus, and Listeria species. Lactocin GI3 had a broader spectrum, inhibiting Bacillus, Clostridium, Listeria, Enterococcus, Leuconostoc, Pediococcus, and Staphylococcus species. Both bacteriocins remained active when heated at 90 degrees C for 15 min or 120 degrees C for 20 min. Leucocin BC2 assayed at 37 degrees C showed an inhibitory activity of 1,600 AU/ml, whereas at 8 degrees C the activity was 12,800 AU/ml. Conversely, lactocin GI3 activity was the same at both assay temperatures. Both bacteriocins remained active over a pH range of 2.0 to 9.0 and in various organic solvents. The activity of leucocin BC2 was increased when treated with 0.5% acetic acid and 0.5% lactic acid, whereas lactocin GI3 activity was decreased with either acid. The molecular mass values were 3.7 kDa for leucocin BC2 and 3.9 kDa for lactocin GI3. These results show that the inhibitory substances produced by the bacteria isolated from garlic and ginger are bacteriocins that appear to be different in some characteristics from previously reported bacteriocins.

Bacteria↗
PubMed1989

[Properties of bacteriocins of Morganella morganii].

Some properties of Morganella morganii bacteriocins were determined. For this purpose two strains (115 and 137) which after mitomycin C induction produced bacteriocins in high titer were chosen. The influence of several physical and chemical factors such as: heating and storage at various temperatures, a freezing and thawing, an influence of buffered fluid of different pH, and digestion by trypsin, papain and lysozyme were investigated. Range of bacteriocin activity against various microorganisms and the ability to diffuse in agar were also determined. It was found on the basis of the results obtained that two bacteriocins showed different features. Bacteriocin "115" was thermostable, sensitive to proteolytic enzymes, able to diffuse in 1.5% agar. Bacteriocin designated "137" was thermolabile, intensive to proteolytic digestion, and incapable to diffuse in 1.5% agar. Activity of both bacteriocins was reduced after freezing and thawing. They were both insensitive to lysozyme digestion. Storage at room temperature reduced their activity faster than storage at the temperature of refrigerator. Their activity was completely stopped at pH 3.03, and significantly at pH 5.08 while environment of pH ranged from 7.08 to 11.0 did not influence their activity. Both bacteriocins showed narrow range of activity limited to the growth inhibition of sensitive strains belonging to Morganella morganii genus.

Bacterial Typing Techniques↗
PubMed1981

[Bacteriocin typing of Enterobacter cloacae strains (author's transl)].

By means of bacteriocin typing epidemic studies were carried out with regard to 65 strains of Enterobacter cloacae, isolated from various specimens of 59 patients. Based on detailed preliminary investigations the presentation with bacteriocins in liquid cultures induced by Mitomycin C was found most preferable. Since constant and reproducible results are essential, standardization of culture media, incubation temperature, incubation time and inoculum size is required. By means of 13 bacteriocin-producing strains the isolates could be typed and categorized into 24 types according to their sensitivity to bacteriocins. A rather varied picture emanated from the distribution of the individual types with regard to the different medical fields so that cross-infection with a certain strain was negligible. Seeing that one bacteriocin type was found predominantly in the intensive care unit, it can be maintained that this strain originated from the ward itself. The importance of bacteriocin typing for the interpretation of certain up-to-date epidemic situations is obvious which typing has also been successfully employed with regard to investigations of Enterobacter cloacae infections. However, it is doubtful whether bacteriocin production and bacteriocin sensitivity sufficiently constant in order to obtain comparable results over a more extended period of time and in different areas.

Bacteriocins↗
PubMed2026

Harnessing Probiotic LAB and Bacteriocins for Clean-Label Food Processing and Biopreservation: Omics, Molecular Innovations and Industrial Applications.

The persistence of microbial agents in foods, especially spore forming bacteria is one of the most significant challenges to food preservation and safety, undermining product quality, shelf life, and consumer health. The use of traditional control methods, including thermal processing and chemical preservatives, are increasingly limited by consumer demands for minimally processed foods, and the emergence of resistant microbial strains. Advances have been made in the use of probiotics like lactic acid bacteria (LAB) and their biometabolites like bacteriocins in food processing and preservation, particularly to control biofilm and endospore forming pathogens including Bacillus sp., Listeria sp., Staphylococcus sp., Clostridium sp., E. coli etc. in foods and food processing plants/surfaces. Given the ability of these organisms to cause foodborne illness and form resilient biofilms in the food processing ecosystem and their resistance to the conventional method of their elimination, the antimicrobial peptides (bacteriocins) are gaining increasing prominence as useful alternatives to synthetic antimicrobials in enhancing food safety and combating the threats of these pathogens. This review addresses current information on the inhibition of persistent microbial spoilage contaminants, biofilm-forming pathogens, and spore formers of interest to the food industry using LAB and their bacteriocins. Current developments in isolation, characterization, and mode of action of bacteriocins are explored, including synergistic activity with other preservative hurdle techniques such as encapsulation, and nanobiotechnology. Importantly, there is a focus on the utilization of molecular and omics-based approaches to enable a better understanding of bacteriocin biosynthesis, gene regulation, host-microbe interactions and gut microbiome regulation potential of probiotic LABs, permitting the rational development of targeted and strain-specific interventions. Developments in the incorporation of bacteriocin-producing LAB into functional starter cultures and bio-protective products, and challenges in stability, regulatory approval, and scalability for industrial use, are also discussed in the paper. Despite their considerable potential, broader translation remains constrained by regulatory requirements, production and formulation costs, variable efficacy in complex food matrices, and the limited validation of many candidate bacteriocins beyond laboratory and model-food systems. Collectively, these advances position LAB and their bacteriocins at the leading edge of developing sustainable, clean-label, and efficacious functional foods and food preservation systems. Their functionality can be expanded by integrating genomics, synthetic biology, and predictive modeling for the maximization of their biopreservative potential in diverse food matrices and in gut microbiota modulation.

Bioactive Peptides↗
PubMed1983

Potential of lactic streptococci to produce bacteriocin.

A survey was made on the bacteriocin-producing potential of lactic streptococci. Bacteriocin-like activities were isolated and partially purified from about 5% of the 280 strains investigated. The frequency of production varied from about 1% in Streptococcus lactis subsp. diacetylactis to 9 and 7.5% in S. lactis and Streptococcus cremoris, respectively. Eight strains of S. cremoris produced bacteriocins which, on the basis of heat stability at different pH values and inhibitory spectrum, could be divided into four types. From 54 S. lactis strains, 5 strains produced inhibitory substances, namely, three nisin-like antibiotics and two different bacteriocins. Only 1 of 93 S. lactis subsp. diacetylactis strains produced a bacteriocin which was very similar to bacteriocins of type I in S. cremoris. All of the bacteriocins that were partially purified by ammonium sulfate precipitation showed very limited inhibitory spectra. Most of the lactic streptococci and a few members of the genera Clostridium, Leuconostoc, and Pediococcus were inhibited. None of the bacteriocins acted on gram-negative bacteria. The bacteriocinogenic strains were also characterized on the basis of plasmid content. All strains possessed between one and nine plasmids ranging from 1 to 50 megadaltons.

Journal Article↗
PubMed2025

Systematically investigating and identifying bacteriocins in the human gut microbiome.

Human gut microbiota produces unmodified bacteriocins, natural antimicrobial peptides that protect against pathogens and regulate host physiology. However, current bioinformatic tools limit the comprehensive investigation of bacteriocins' biosynthesis, obstructing research into their biological functions. Here, we introduce IIBacFinder, a superior analysis pipeline for identifying unmodified class II bacteriocins. Through large-scale bioinformatic analysis and experimental validation, we demonstrate their widespread distribution across the bacterial kingdom, with most being habitat specific. Analyzing over 280,000 bacterial genomes, we reveal the diverse potential of human gut bacteria to produce these bacteriocins. Guided by meta-omics analysis, we synthesized 26 hypothetical bacteriocins from gut commensal species, with 16 showing antibacterial activities. Further ex vivo tests show minimal impact of narrow-spectrum bacteriocins on human fecal microbiota. Our study highlights the huge biosynthetic potential of unmodified bacteriocins in the human gut, paving the way for understanding their biological functions and health implications.

Humans↗
PubMed1997

Production of nisin-like bacteriocins by Lactococcus lactis strains isolated from vegetables.

Four bacteriocin producing lactic acid bacteria isolated from vegetables were identified as Lactococcus lactis strains on the basis of physiological and biochemical characteristics, carbohydrate fermentation patterns and analysis of total soluble protein pattern by SDS PAGE. The bacteriocins had a wide spectrum of activity as antagonism was detected not only towards a variety of lactic acid bacteria, but also to Staphylococcus aureus and Listeria monocytogenes. These bacteriocins were resistant to heating at 121 degree C for 15 minutes and showed highest activity at low pH (<5.0). They were inactivated by the proteolytic enzymes alpha-chymotrypsin and proteinase K, but not by lipase, alpha-amylase, catalase or lysozyme. These bacteriocinogenic Lactococcus strains were all immune to the bacteriocins produced as well as to commercial nisin. Bacteriocin producer culture supernatants showed a high degree (70 or 100%) of cross-reactivity in the nisin ELISA, suggesting similarity of the produced bacteriocins to nisin. The potential application of bacteriocin producing lactococci of vegetable origin for safety assurance of vegetable foods and controlling vegetable fermentations is discussed.

Anti-Bacterial Agents↗