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 541 records · Page 30Linked to original sources
PubMed1998

Isolation and characterization of two bacteriocins of Lactobacillus acidophilus LF221.

Lactobacillus acidophilus LF221 produced bacteriocin-like activity against different bacteria including some pathogenic and food-spoilage species. Besides some lactic acid bacteria, the following species were inhibited: Bacillus cereus, Clostridium sp., Listeria innocua, Staphylococcus aureus, Streptococcus D. L. acidophilus LF221 produced at least two bacteriocins, acidocin LF221 A and acidocin LF221 B, which were purified by ammonium sulphate precipitation, ion-exchange chromatography, hydrophobic interaction and reverse-phase FPLC. The antibacterial substances were heat-stable, sensitive to proteolytic enzymes (trypsin, pepsin, pronase, proteinase K) and migrated as 3500- to 5000-Da proteins on sodium dodecyl sulphate/polyacrylamide gel electrophoresis. The sequences of 46 amino-terminal amino acid residues of peptide A and 35 of peptide B were determined. Among the residues identified, no modified amino acids were found. No significant homology was found between the amino acid sequences of acidocin LF221 A and other bacteriocins of lactic acid bacteria and 26% homology was found between acidocin LF221 B and brevicin 27. L. acidophilus LF221 may be of interest as a probiotic strain because of its human origin and inhibition of pathogenic bacteria, especially clostridium difficile.

Amino Acid Sequence↗
PubMed1987

Recognition of T-cell murine leukemia by bacteriocin (colicin); correlation with transplantation experiments.

The presence of potential murine leukemia and overt leukemia cells in various organs at different phases of leukemogenesis was demonstrated by transplantation experiments and sensitivity to bacteriocin (colicin HSC10). Such correlation was found in three experimental models: AKR mice developing spontaneous T-cell leukemia and BL/6 mice infected with radiation leukemia virus variants inducing a high or low overt T-cell leukemia incidence. The sensitivity to bacteriocin was evaluated by testing the cell cycle perturbation following in-vitro incubation of lymphoid cells with colicin (or Tris buffer as controls) monitored by flow-cytometry. The analysis was based on measuring relative differences in fluorescence intensity of propidium iodide stained DNA in the individual cells. The interaction with colicin of leukemic cells and lymphoid cells containing potential leukemic cells (PLC) resulted in a reduction in the cell number of the G0/G1 and SG2M phases while cells accumulated in the "pre-G1" channels. In contrast, normal lymphoid cells exposed to bacteriocin did not show such changes in the DNA histograms. The distribution pattern of PLC in the thymus and spleen (in the models tested) obtained by transplantation studies coincided with sensitivity of spleen and thymus cells to colicin. However, in most instances, the PLC in the bone marrow were not recognized by colicin, but their leukemogenic potential was reduced following interaction with colicin as shown by PLC transplantation studies. It is thus suggested that colicin might be used for identification and eradication of transformed cells.

Age Factors↗
PubMed1995

Antilisterial activity of thermophilin 347, a bacteriocin produced by Streptococcus thermophilus.

Streptococcus thermophilus 347 isolated from yogurt produces a bacteriocin referred as thermophilin 347. The bacteriocin was evidenced in the neutralized, filtered and catalase treated culture supernatant fluid of the producer strain. After partial purification, thermophilin 347 exhibited a bactericidal effect against Listeria monocytogenes and several closely related lactic acid bacteria. The activity of thermophilin 347 was lost after protease treatment but was maintained after heating at 100 degrees C for 1 h; after autoclaving at 121 degrees C for 15 min the activity was reduced by 50%. SDS-PAGE of partially purified thermophilin 347 was used to detect bacteriocin activity corresponding to an apparent molecular mass between 2.5 and 6.2 KDa.

Bacteriocins↗
PubMed1994

Effect of the bacteriocin carnocin CP5 and of the producing strain Carnobacterium piscicola CP5 on the viability of Listeria monocytogenes ATCC 15313 in salt solution, broth and skimmed milk, at various incubation temperatures.

Carnobacterium piscicola CP5, isolated from French mould-ripened soft-cheese, produced a bacteriocin named carnocin CP5 in a wide range of incubation temperatures, from 4 degrees C to 30 degrees C. The ability of a crude bacteriocin, of a partially-purified form, and of the producer strain to inhibit growth of Listeria monocytogenes ATCC 15313 was examined in salt solution, broth and skimmed milk between 4 degrees C and 30 degrees C. When carnocin CP5 was added to a L. monocytogenes ATCC 15313 culture, an adsorption on cells and a bactericidal effect with a cell lysis occurred. At 30 degrees C, with carnocin CP5 or with C. piscicola CP5, a transitory bactericidal effect was observed. Subsequent experiments at 4 degrees C, 7 degrees C or 15 degrees C, showed a more prolonged bactericidal effect. Thus at 7 degrees C, partially-purified carnocin CP5 reduced an initial population level of L. monocytogenes of 10(3) cfu/ml to non-detectable level within 7 days. However, in some cases, with extended incubation, the carnocin CP5 effect was no longer visible, the L. monocytogenes population grew again. This phenomenon was probably due to the presence of a sub-population of bacteriocin-resistant variants.

Animals↗
PubMed1996

Purification, partial characterisation and mode of action of enterococcin EFS2, an antilisterial bacteriocin produced by a strain of Enterococcus faecalis isolated from a cheese.

Enterococcus faecalis strain EFS2, isolated from the surface of a traditional cheese, produced a bacteriocin active against Gram-positive bacteria including Listeria spp. and some Staphylococcus aureus strains. The bacteriocin, named enterococcin EFS2, has been purified to homogeneity by ammonium sulphate precipitation and reversed-phase high performance liquid chromatography (RP-HPLC). The molecular weight was determined by mass spectrometry to be 7149.6. The amino acid composition of enterococcin EFS2 revealed that it contained 67 amino acid residues and had a blocked amino-terminal end. Enterococcin EFS2 induced viability loss, efflux of K+ ions and ATP, and cell lysis. Kinetic study of bactericidal activity of enterococcin EFS2 on Listeria innocua strain LIN11 indicated slower cell destruction than by nisin. At pH 7.0, the activity of enterococcin EFS2 was the highest at 35 degrees C and was lost at 15 degrees C. The bacteriocin was more active against L. innocua strain LIN11 in broth adjusted to pH 6.0, 7.0 and 8.0 than to pH 4.5 at 30 degrees C.

Amino Acids↗
PubMed1996

Leucocin F10, a bacteriocin from Leuconostoc carnosum.

Leucocin F10 is a bacteriocin produced by a strain of Leuconostoc carnosum isolated from fermented meat. It is sensitive to proteolytic enzymes and alpha-amylase, heat resistant up to 121 degrees C for 10 min at pH 3.0 and is inhibitory to Listeria spp., Leuconostoc spp., Enterococcus faecalis and Lactobacillus sake. Bactericidal activity against L. innocua in potassium phosphate buffer was strongly dependent of the growth phase of the indicator cells. A rapid sub-lethal damage, followed by slow death was observed for log-phase cells of L. innocua. The bacteriocin induced a rapid release of K+ from energized L. innocua cells. Leucocin F10 production occurred at temperatures between 4 and 30 degrees C and followed a primary metabolite kinetics in batch fermentations at controlled pH. Maximum bacteriocin activity was obtained at pH 6.0.

Bacteriocins↗
PubMed1988

Bacteriocins of lactic acid bacteria.

Lactic acid bacteria produce a variety of antagonistic factors that include metabolic end products, antibiotic-like substances and bactericidal proteins, termed bacteriocins. The range of inhibitory activity by bacteriocins of lactic acid bacteria can be either narrow, inhibiting only those strains that are closely related to the producer organism, or wide, inhibiting a diverse group of Gram-positive microorganisms. The following review will discuss biochemical and genetic aspects of bacteriocins that have been identified and characterized from lactic acid bacteria.

Bacteriocins↗
PubMed1994

Extraction, partial purification and characterization of a bacteriocin (fragicilin) produced by a strain of Bacteroides fragilis isolated from Callithrix penicillata.

A strain of Bacteroides fragilis, isolated from the marmoset Callithrix penicillata, produced protein(s) with bacteriocin activity (fragicilin). Two active fractions (36 and 150 kDa) were isolated by chromatography. The bacteriocin exhibited iso- and heteroantagonism. It remained stable between pH 3 and 10 and at 60 degrees C for 24 h. Pronase, trypsin, proteinase K and type VII protease inactivated the bacteriocin, giving evidence of its protein nature.

Animals↗
PubMed2006

Application of the broad-spectrum bacteriocin enterocin AS-48 to inhibit Bacillus coagulans in canned fruit and vegetable foods.

The enterococcal bacteriocin (enterocin) AS-48 is a broad-spectrum cyclic peptide. Enterocin AS-48 was tested against Bacillus coagulans in three vegetable canned foods: tomato paste (pH 4.64), syrup from canned peaches (pH 3.97), and juice from canned pineapple (pH 3.65). When vegetative cells of B. coagulans CECT (Spanish Type Culture Collection) 12 were inoculated in tomato paste supplemented with 6 microg/ml AS-48 and stored at different temperatures, viable cell counts were reduced by approximately 2.37 (4 degrees C), 4.3 (22 degrees C) and 3.0 (37 degrees C) log units within 24 h storage. After 15-days storage, no viable cells were detected in any sample. Strain B. coagulans CECT 561 showed a poor survival in tomato paste, but surviving cells were also killed by AS-48. The bacteriocin was also very active against B. coagulans CECT 12 vegetative cells in juice from canned pineapple stored at 22 degrees C, and slightly less active in syrup from canned peaches. In food samples supplemented with 1.5% lactic acid, enterocin AS-48 (6 microg/ml) rapidly reduced viable counts of vegetative cells below detection limits within 24 h storage. Addition of glucose and sucrose (10% and 20%) significantly increased bacteriocin activity against vegetative cells of B. coagulans CECT 12. Enterocin AS-48 had no significant effect on B. coagulans CECT 12 spores. However, the combined application of AS-48 and heat (80-95 degrees C for 5 min) significantly increased the effect of thermal treatments on spores.

Bacillus↗
PubMed2004

Transcriptional analysis of bacteriocin production by malt isolate Lactobacillus sakei 5.

Malt isolate Lactobacillus sakei 5 produces three bacteriocins, sakacin P, sakacin T and sakacin X. The structural and regulatory genes for sakacin T and sakacin X are part of the sakacin TX locus, which consists of two adjacent, but divergently oriented gene clusters. Primer extension transcriptional analysis pointed to the existence of three distinct promoters within the sakacin TX locus, indicating that the three-component regulatory system in this locus is atypical in the sense that it is divided into a pheromone-specifying operon and an operon containing the genes for the histidine protein kinase and response regulator. Quantitative real-time PCR analyses showed that a transient increase in the expression of these two regulatory operons precedes transcription of the bacteriocin genes and appearance of bacteriocins in the culture medium. The identified promoters of the sakacin TX locus contain putative regulatory sequences (direct repeats) at corresponding positions in front of their -10 regions, which are likely to play a role in gene regulation.

Bacterial Proteins↗
PubMed2006

Evidence on correlation between number of disulfide bridge and toxicity of class IIa bacteriocins.

The aim of this work was to study in the same microbiological conditions and for the first time the inhibitory action of eight class IIa bacteriocins against 23 Gram-positive bacteria in which some of them are industrially used as starters and against the eight class IIa bacteriocins producing strains themselves. The sensitivity of each strain was determined after MPA using the mathematical model described by Cabo et al. (1999, J. Appl. Microbiol. 87, 907-914). Therefore, the principal component analysis realized led to a strong correlation between spectrum and extra-disulfide bridge and a minor correlation between spectrum and isoelectric point of each bacteriocin.

Bacteriocins↗
PubMed2005

Fed-batch enhancement of jenseniin G, a bacteriocin produced by Propionibacterium thoenii (jensenii) P126.

Jenseniin G is an antibotulinal bacteriocin (antimicrobial peptide) produced by the dairy culture, Propionibacterium thoenii (jensenii) P126. Activity from crude jenseniin G preparations isolated from static cultures was not detected in unconcentrated cultures before day 7. Activity was not detectable until the spent culture medium was concentrated 50-100 fold. Maximum activity (21 AU/ml) was observed in concentrated supernates at day 9. The production of bacteriocin jenseniin G was increased in fed-batch fermentations for 14 d at 32 degrees C in sodium lactate broth (NLB) containing 1.2% sodium lactate. Viable cell numbers in static and fed-batch cultures reached 1.2 and 5.4x10(9), respectively, during late exponential/early stationary phase (3 d). Concentrations of viable cells in fed-batch fermentations remained constant throughout the incubation period; those in static fermentations dropped after day 6 to a final concentration of 1.5x10(7). During fed-batch fermentations, jenseniin G was directly detected at day 5. In fed-batch fermentations, maximum activity in concentrated supernates (384 AU/ml) on day 12 provided an 18 fold increase over yields in static cultures and in fermenter without pH control, and 2.4 fold increase over yields in fermenter at controlled pH at 6.4. Fed-batch fermentation shows promise as a method to obtain high concentrations of industrially significant bacteriocins from dairy propionibacteria.

Bacteriocins↗
PubMed2006

Reduction of Escherichia coli population following treatment with bacteriocins from lactic acid bacteria and chelators.

The inhibitory activity of lactocin 705/AL705 (2133 arbitrary units per ml (AU ml(-1))), two bacteriocins produced by Lactobacillus curvatus CRL705 and nisin (1066AU ml(-1)) produced by Lactococcus lactis CRL1109 in combination with chelating agents against Escherichia coli strains in TSB medium at 21 and 6 degrees C was investigated. Treatment with EDTA (500 and 1000 mm) and Na lactate (800 mm) alone produced a variable effect depending on the strain, Na lactate being inhibitory against E. coli NCTC12900 at both assayed temperatures while EDTA (1000 mm) led to its inactivation only at 6 degrees C. Direct and deferred strategies using EDTA and Na lactate showed that the direct addition of bacteriocins and chelators was not as effective as compared to deferred treatments. When the deferred treatment effectiveness was evaluated at 6 degrees C, the use of EDTA (500 and 1000 mm) and Na lactate (800 mm) in combination with lactocin 705/AL705 demonstrated to be the most inhibitory strategy against both E. coli strains. Nevertheless, treatments with chelators and bacteriocins was highly dependent upon strain sensitivity. Permeabilization of the outer membrane of E. coli strains with EDTA and Na lactate combined with lactocin 705/AL705 showed to be valuable in controlling this foodborne bacteria at low temperatures.

Anti-Bacterial Agents↗
PubMed2004

Characterization of thoeniicin 447, a bacteriocin isolated from Propionibacterium thoenii strain 447.

Fifteen strains of propionibacteria, isolated from dairy products, were screened for the production of bacteriocins. Propionibacterium thoenii 447 produced an antimicrobial peptide, thoeniicin 447, which acted bactericidal against Lactobacillus delbrueckii subsp. bulgaricus and bacteriostatic against Propionibacterium acnes. Thoeniicin 447 remained active after 15 min at 100 degrees C and after 30 min of incubation at pH 1-10. The peptide was inactivated when treated with pepsin, pronase, alpha-chymotrypsin, trypsin and proteinase K. Optimal bacteriocin production was detected during late exponential growth. The peptide was partially purified by ammonium sulfate precipitation, followed by SP-Sepharose cation exchange chromatography. The estimated size of thoeniicin 447, according to tricine-SDS-PAGE, is 6 kDa. Based on DNA sequencing, the mature peptide is 7130.20 Da in size and homologous to propionicin T1, produced by P. thoenii strain 419 (=NCFB 568(T)). Strain 447 is phenotypically different from strain 419 and belongs to a separate ribotype cluster. To our knowledge, this is the first report of a bacteriocin from a Propionibacterium species active against P. acnes.

Amino Acid Sequence↗
PubMed2005

Lactococcin MMT24, a novel two-peptide bacteriocin produced by Lactococcus lactis isolated from rigouta cheese.

Lactococcin MMT24 is a novel bacteriocin produced by Lactococcus lactis MMT24, a strain isolated from a Tunisian traditional cheese. The bacteriocin shows a narrow antimicrobial activity against closely related lactic acid bacteria. Lactococcin MMT24 is heat resistant, remains active after incubation at pH 3 to 10, lyophilization, long-term storage at -20 degrees C and is sensitive to treatment with proteolytic enzymes. The mode of action of lactococcin MMT24 was identified as bactericidal. Purification of the active compound showed that lactococcin MMT24 consists of two distinct peptides, named pepalpha and pepbeta, whose complementary action is necessary for full antibacterial activity. Optimal antibacterial activity was obtained when the complementary peptides pepalpha and pepbetawere present in equal amounts. Mass spectrometry analysis showed masses of 3765.33 Da and 3255.26 Da for pepalpha and pepbeta, respectively. These molecular masses do not correspond to those of so far described bacteriocins. Addition of 50 nmol l(-1) of lactococcin MMT24 to cells of L. lactis ssp. cremoris ATCC11603 induced increase in the concentration of K+ in supernatant indicating a massive leakage of this ion from the cells. This release was most likely caused by pores formation by the pepalphaand pepbeta peptides in the target bacterial membrane.

Anti-Bacterial Agents↗
PubMed2006

Detection of antimicrobial activities and bacteriocin structural genes in faecal enterococci of wild animals.

The production of antimicrobial activities as well as the presence of bacteriocin structural genes (entA, entB, entP, entQ, cylL, entAS-48, bac31, and entL50A/B) were studied in 140 non-selected faecal enterococcal isolates recovered from wild animals. Eight different indicator strains (including Listeria monocytogenes, Pediococcus pentosaceus, and different enterococcal species) were used for antimicrobial activity detection. Twenty-five of the 140 enterococci (18%) showed antimicrobial activity against L. monocytogenes and 33 additional isolates (24%) showed antimicrobial activity against other indicator strains, but Listeria. At least one bacteriocin structural gene was detected in 17 of the 25 enterococci with antimicrobial activity against L. monocytogenes and different combinations of entA, entB, entP, entQ, entL50A/B, and cylL genes were detected; entA and entB were the most prevalent detected genes, and they were generally associated. Bacteriocin structural genes were detected in 10 of 33 isolates with antimicrobial activity against indicator strains other than Listeria, and the cylL gene was the most prevalent one, especially in E. faecalis isolates.

Animals↗
PubMed2005

Genomic fingerprinting of bacteriocin-producer strains of Staphylococcus aureus.

Among 363 strains of Staphylococcus aureus, 21 were shown to produce bacteriocins (Bac), antimicrobial peptides with potential biotechnological applications. This collection includes strains which are either isolated from food, patients and healthy cattle, or are involved in subclinical bovine mastitis. From these 21 strains, 17 were shown to carry closely-related 8.0-kb Bac plasmids encoding bacteriocins either identical to or similar to aureocin A70, a bacteriocin able to inhibit strains of Listeria monocytogenes, a food-borne pathogen. Such findings prompted us to investigate the genetic relationships among these Bac+ strains. To obtain more discriminatory results, a combined analysis of AP-PCR, rep-PCR, and a modified PCR technique that we designated SD-PCR was employed. The 17 Bac+ strains harboring 8.0-kb Bac plasmids exhibited seven fingerprint patterns. One such genotype was composed of 8 out of the 11 strains associated with bovine mastitis, which suggests the prevalence of a clone of Bac+ strains involved in this animal infection carrying 8.0-kb Bac plasmids. Our data support the assumption that Bac+ strains of S. aureus carrying genetically related 8.0-kb Bac plasmids do not belong to a single clone. It seems, therefore, that 8.0-kb Bac plasmids have spread horizontally among different S. aureus strains. There also seems to be genetic diversity among the remaining Bac+ strains analyzed.

Bacteriocins↗
PubMed2001

Use of a bacteriocin-producing transconjugant as starter in acceleration of cheese ripening.

The non-conjugative 46 kb plasmid that encodes the biosynthesis of lacticin 3147 in Lactococcus lactis IFPL105 has been transferred to the starter L. lactis IFPL359, used in goat's milk cheesemaking. The accelerating effect exerted on proteolysis and development of sensory characteristics of semi-hard cheese by the bacteriocin-producing transconjugant L. lactis IFPL3593 (Lac+ Bac+ Imm+), which is able to induce cell lysis in starter adjuncts with high peptidase activity, has been studied. It has been demonstrated that the use of IFPL3593 as starter accelerates cheese ripening as it increases the level of amino nitrogen correlated with early cell lysis of adjuncts. The fact that the bacteriocin-producing microorganism used is immune to the bacteriocin. allowed proper acidification of the curd without altering the cheese-making process.

Animals↗