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 577 records · Page 32Linked to original sources
PubMed2000

Isolation and characterization of a new bacteriocin from Lactobacillus gasseri KT7.

A bacteriocin-producing Lactobacillus gasseri strain, KT7, was isolated from infant faeces. The supernatant fluid showed inhibitory activity not only against some lactic acid bacteria but also, against some pathogenic and food-spoilage species, including Clostridium, Listeria and Enterococcus. An antimicrobial peptide designated gassericin KT7 was isolated from Lactobacillus gasseri KT7. It was purified to homogeneity by a single four-step procedure: a crude supernatant fluid obtained from early stationary-phase culture in MRS medium was subjected to ammonium sulphate fractionation, CM-Sephadex cation-exchange chromatography, Phenyl-Sepharose hydrophobic chromatography and reverse-phase HPLC chromatography. Gassericin KT7 was sensitive to proteolytic enzymes, resistant to heat, active over a wide range of pH, and migrated as a 4.5-5.0 kDa peptide on SDS-PAGE. The bacteriocin was produced constitutively during exponential growth. It was bactericidal to sensitive cells and the bactericidal effect was not produced by cell lysis. The amino acid composition of the bacteriocin was determined and no modified amino acid was found among the residues identified.

Amino Acids↗
PubMed2001

Purification and characterization of a bacteriocin-like compound (Lichenin) produced anaerobically by Bacillus licheniformis isolated from water buffalo.

AIMS: To characterize a bacteriocin-like factor from Bacillus licheniformis 26 L-10/3RA isolated from buffalo rumen. METHODS AND RESULTS: The culture supernatant exhibited the antibacterial activity against a number of indicator organisms in a cut-well agar assay under anaerobic conditions. The inhibitory component was purified by following ammonium sulphate precipitation, gel filtration and ion exchange chromatography and confirmed to be a single peptide. A single band on tricine-sodium dodecyl sulphate-polyacrylamide gel electrophoresis confirmed that the peptide was purified to homogeneity and having an estimated molecular mass of approximately 1400 dalton. Complete amino acid sequence of the peptide yielded 12 amino acids from the N-terminal end (ISLEICXIFHDN). No homology with previously reported bacteriocins was observed and has been designated as Lichenin. Lichenin was found to be hydrophobic, sensitive to atmospheric oxygen, retained biological activity even after boiling for 10 min and was active over a pH range of 4.0-9.0. CONCLUSIONS: The Lichenin represents the first anaerobiosis specific expression of bacteriocin-like compound isolated from Bacillus licheniformis 26 L-10/3RA of buffalo rumen origin. SIGNIFICANCE AND IMPACT OF THE STUDY: Lichenin could be a potential candidate for manipulating the rumen function at molecular level intended for improving the productivity of the ruminant.

Anaerobiosis↗
PubMed1997

Generation of polyclonal antibodies against a chemically synthesized N-terminal fragment of the bacteriocin pediocin PA-1.

Six mice were immunized intraperitoneally (i.p.) with a chemically synthesized 9-mer fragment (PH1) designed from the N-terminal part of the bacteriocin pediocin PA-1 and conjugated to keyhole limpet haemocyanin (KLH). After three doses of the immunogen had been administered, serum-specific antibodies were detected by a competitive direct ELISA. Myeloma cells were injected i.p. into mice in order to obtain ascites polyclonal antibodies. Although four mice developed ascites, only mouse 2 had detectable specific antibodies in the ascites fluid. The serum and ascites antibodies were specific for PH1 but they did not recognize the whole pediocin PA-1 molecule. This is the first attempt to generate antibodies against bacteriocins with a chemically synthesized oligopeptide as immunogen. This approach still remains attractive for detection, quantification, mode of action studies and purification of bacteriocins, especially those for which the purification process is difficult or inefficient at present.

Amino Acid Sequence↗
PubMed2000

Triton X-114 phase partitioning for the isolation of a pediocin-like bacteriocin from Carnobacterium divergens.

A new procedure combining Triton X-114 phase partitioning and cation exchange chromatography was developed to purify a bacteriocin from a complex culture medium. This pediocin-like bacteriocin, secreted by Carnobacterium divergens and named divercin V41, was entirely recovered in the lower detergent-rich phase whereas all other substances (compounds from culture medium, bacterial metabolites) remained in the upper detergent-poor phase. Subsequent cation-exchange chromatography of the TX-114-rich phase allowed recovery of the pure active bacteriocin and also detergent removing. This new purification method is versatile, fast (only two steps) and can be carried out on whole broth.

Bacteria↗
PubMed2000

Lactobacillus farciminis MD, a newer strain with potential for bacteriocin and antibiotic assay.

A native isolate Lactobacillus farciminis MD isolated from fermenting mushroom exhibited a high degree of sensitivity to the majority of the bacteriocins produced by strains of lactobacilli, leuconostoc and pediococci. Also, the efficacy of Lact. farciminis MD as a sensitive strain for antibiotic assay was established against different antibiotics including ampicillin, cefazoline, chloramphenicol and nitrofurantoin at concentrations of 30 microg each, showing an inhibition zone of 30 mm diameter. The high degree of sensitivity towards bacteriocins and antibiotics provide potential for the exploitation of Lact. farciminis MD in establishing very well-defined bacteriocin producers.

Agaricales↗
PubMed2001

Partial characterization of a bacteriocin produced by Lactobacillus helveticus.

AIMS: To investigate the antimicrobial activity of a strain of Lactobacillus helveticus. METHODS AND RESULTS: The culture supernatant fluid Lact. helveticus G51 showed antimicrobial activity against thermophilic strains of Lactobacillus. Purification of the active compound was achieved after gel filtration and ion exchange chromatography. As revealed by SDS-PAGE, active fractions were relatively homogeneous, showing a protein with a molecular mass of 12.5 kDa. The antimicrobial compound was heat labile, inactivated by proteolytic enzymes and had a bactericidal mode of action. CONCLUSION: The antimicrobial activity expressed by Lact. helveticus G51 was correlated with the production of a bacteriocin with properties that were different to other helveticins. SIGNIFICANCE AND IMPACT OF THE STUDY: The study has provided further data on Lact. helveticus bacteriocins. The strong activity of the bacteriocin towards various thermophilic lactobacilli warrants further investigation for its potential to obtain attenuated cultures for the enhancement of the cheese-ripening process.

Bacteriocins↗
PubMed1999

Membrane topology of the lactococcal bacteriocin ATP-binding cassette transporter protein LcnC. Involvement of LcnC in lactococcin a maturation.

Many non-lantibiotic bacteriocins of lactic acid bacteria are produced as precursors with N-terminal leader peptides different from those present in preproteins exported by the general sec-dependent (type II) secretion pathway. These bacteriocins utilize a dedicated (type I) secretion system for externalization. The secretion apparatus for the lactococcins A, B, and M/N (LcnA, B, and M/N) from Lactococcus lactis is composed of the two membrane proteins LcnC and LcnD. LcnC belongs to the ATP-binding cassette transporters, whereas LcnD is a protein with similarities to other accessory proteins of type I secretion systems. This paper shows that the N-terminal part of LcnC is involved in the processing of the precursor of LcnA. By making translational fusions of LcnC to the reporter proteins beta-galactosidase (LacZ) and alkaline phosphatase (PhoA*), it was shown that both the N- and C-terminal parts of LcnC are located in the cytoplasm. As the N terminus of LcnC is required for LcnA maturation and is localized in the cytoplasm, we conclude that the processing of the bacteriocin LcnA to its mature form takes place at the cytosolic side of the cytoplasmic membrane.

ATP-Binding Cassette Transporters↗
PubMed1984

Epidemiology of colitis induced by Clostridium difficile in hamsters: application of a bacteriophage and bacteriocin typing system.

The epidemiology of colitis induced by Clostridium difficile in hamsters was studied with a new bacteriophage and bacteriocin typing system. Fatal enterocolitis was induced by administration of N-formimidoyl thienamycin. Environmental cultures were obtained repeatedly throughout the experiments. Thirteen percent of 90 healthy hamsters were already colonized with C difficile on arrival from the supplier. Mortality from enterocolitis after antibiotic administration was 75% and was not diminished by use of a laminar-flow facility. The same uncommon bacteriocin type (83/1309/2329) of toxigenic C difficile that colonized hamsters on arrival was recovered from the cecal contents of all hamsters dying with enterocolitis and from most environmental isolates. Previously uncolonized , antibiotic-treated hamsters placed into cages where animals had died from enterocolitis also developed enterocolitis with the same bacteriocin type (83/1309/2329), an outcome suggesting acquisition of C difficile from the environment.

Animals↗
PubMed2003

The bacteriocin piscicolin 126 retains antilisterial activity in vivo.

OBJECTIVE: We have conducted a series of experiments to show that the bacteriocin piscicolin 126 (P126) retains antilisterial activity after injection into a mouse. METHODS: Groups of mice were challenged intravenously with Listeria monocytogenes and treated with purified P126 at varying times before and after challenge to determine whether administration of this peptide reduced numbers of colonizing L. monocytogenes and the symptoms of listeriosis. RESULTS: The bacteriocin P126 retained antilisterial activity after injection into the mouse. During the early time-points of listerial infection, the purified P126 was found to significantly reduce the listerial load in the liver and spleen and, further, that this reduction translated to reduced clinical signs of disease. CONCLUSIONS: This is the first report of a Class IIA bacteriocin displaying in vivo antimicrobial activity. Such a result provides preliminary evidence that this class of molecules may be useful in controlling systemic bacterial infections.

Animals↗
PubMed2007

The spectrum of antimicrobial activity of the bacteriocin subtilosin A.

BACKGROUND: Bacterocins are antimicrobial peptides produced by bacteria with a relatively narrow range of activity against closely related organisms. Subtilosin A is a bacteriocin produced by Bacillus subtilis that has activity against Listeria monocytogenes, which might indicate antimicrobial activity unusual for bacteriocins. OBJECTIVES: To examine the antimicrobial activity and factors affecting the activity of subtilosin A against a range of potentially pathogenic bacteria. METHODS: The peptide was purified from cultures of B. subtilis and the MIC determined for 18 species of bacteria using a microdilution methodology. The extent of capsule formation was determined using microscopic examination of cells mounted in India ink. Protease mutants of a susceptible bacteria and mild heat shock were used to examine the effect of environmental stress on subtilosin A activity. RESULTS: Subtilosin A proved to have antimicrobial activity against a wide range of bacteria including Gram-positive and Gram-negative bacteria and both aerobes and anaerobes. The peptide was less effective against capsulated forms of two Gram-negative bacteria than the non-capsulated strains of either. Heat shock but not protease activity also altered the effectiveness of the bacteriocin. CONCLUSIONS: Subtilosin A has limited antimicrobial activity against a number of human pathogens which, combined with its relative ineffectiveness against some capsulated pathogens, may limit its usefulness as a human therapeutic.

Anti-Bacterial Agents↗
PubMed1991

Plasmid-encoded determinants for bacteriocin production and immunity in a Lactococcus lactis strain and purification of the inhibitory peptide.

Lactococcin, a bacteriocin produced by Lactococcus lactis subsp. lactis ADRIA 85LO30, was purified as a 2.3-2.4 kDa peptide. Six non-bacteriocin-producing (Bac-) and non-immune (Imm-) strains were isolated after curing experiments. These strains had in common the loss or modification of two plasmids: pOS4 (32 kb) and pOS5 (70 kb). By comparing pOS5 and several modified plasmids, a DNA region from pOS5 of about 10 kb, which was necessary for wild-type bacteriocin production and immunity, was identified.

Bacteriocins↗
PubMed1992

Purification and amino acid sequence of sakacin A, a bacteriocin from Lactobacillus sake Lb706.

Sakacin A, a bacteriocin produced by Lactobacillus sake Lb706 and which inhibits the growth of Listeria monocytogenes, was purified to homogeneity by ammonium sulphate precipitation and ion-exchange, hydrophobic-interaction and reversed-phase chromatography. The complete amino acid sequence of sakacin A was determined by Edman degradation. The bacteriocin consisted of 41 amino acid residues and had a calculated M(r) of 4308.7, which is in good agreement with the value determined by mass spectrometry. The structural gene encoding sakacin A (sakA) was cloned and sequenced. The gene encoded a primary translation product of 59 amino acid residues which was cleaved between amino acids 18 and 19 to yield the active sakacin A. Sakacin A shared some sequence similarities with other bacteriocins.

Amino Acid Sequence↗
PubMed1992

Characterization and purification of mesentericin Y105, an anti-Listeria bacteriocin from Leuconostoc mesenteroides.

A Leuconostoc mesenteroides ssp. mesenteroides was isolated from goat's milk on the basis of its ability to inhibit the growth of Listeria monocytogenes. The antimicrobial effect was due to the presence in the culture medium of a compound, named mesentericin Y105, excreted by the Leuconostoc mesenteroides Y105. The compound displayed known features of bacteriocins from lactic acid bacteria. It appeared as a proteinaceous molecule exhibiting a narrow inhibitory spectrum limited to genus Listeria. The apparent relative molecular mass, as indicated by activity detection after SDS-PAGE, was 2.5-3.0 kDa. The bacteriocin was purified to homogeneity by a simple three-step procedure: a crude supernatant obtained from an early-stationary-phase culture in a defined medium was subjected to affinity chromatography on a blue agarose column, followed by ultrafiltration through a 5 kDa cut-off membrane, and finally by reverse-phase HPLC on a C4 column. Microsequencing of the pure bacteriocin and of tryptic fragments showed that mesentericin Y105 is a 36 amino acid polypeptide whose primary structure is close to that of leucocin A-UAL 187, which contains an extra residue at the C-terminus and displays only two differences in the overlapping sequence. However, unlike leucocin A-UAL 187, mesentericin Y105 displayed a bactericidal mode of action.

Amino Acid Sequence↗
PubMed1993

Purification and characterization of plantaricin A, a Lactobacillus plantarum bacteriocin whose activity depends on the action of two peptides.

A Lactobacillus plantarum bacteriocin, plantaricin A, has been purified to homogeneity by ammonium sulphate precipitation, binding to cation exchanger and Octyl-Sepharose, and reverse-phase chromatography. The bacteriocin activity was associated with two peptides, termed alpha and beta, which were separated upon reverse-phase chromatography. Bacteriocin activity required the complementary action of both the alpha and beta peptides. From the N-terminal end, 21 and 22 amino acid residues of alpha and beta, respectively, were sequenced. Further attempts at sequencing revealed no additional amino acid residues, suggesting that either the C terminus had been reached or that modifications in the next amino acid residue blocked the sequencing reaction. Judging from their amino acid sequence, alpha and beta may be encoded by the same gene, since alpha appeared to be a truncated form of beta. Alanine, the first amino acid residue at the N-terminal end of beta was not present at this position in alpha. Otherwise the sequences of alpha and beta appeared to be identical. The calculated molecular masses of the sequenced part of alpha and beta were 2426 and 2497 Da, respectively. The molecular masses of alpha and beta as determined by mass spectroscopy were 2687 +/- 30 and 2758 +/- 30 Da, respectively, indicating that (i) the only difference between alpha and beta was the presence of the N-terminal alanine residue in beta, and that (ii) in addition to the sequenced residues, two to three unidentified amino acid residues are present at the C-terminal ends of the alpha and beta peptides.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1998

Divercin V41, a new bacteriocin with two disulphide bonds produced by Carnobacterium divergens V41: primary structure and genomic organization.

Divercin V41 is a new bacteriocin produced by Carnobacterium divergens V41, a lactic acid bacterium isolated from fish viscera. The amino acid sequence of divercin V41 showed high homologies with pediocin PA-1 and enterocin A. Two disulphide bonds were present in the hydrophilic N-terminal domain and in the highly variable hydrophobic C-terminal domain, respectively. A DNA probe designed from the N-terminal sequence of the purified peptide was used to locate the structural gene of divercin V41. A 6 kb chromosomal fragment containing the divercin V41 structural gene (dvnA) was cloned and sequenced. The results indicate that divercin V41 is synthesized as a pre-bacteriocin of 66 amino acids. The 23-residue N-terminal extension is cleaved off to yield the mature 43-amino-acid divercin V41. In addition, the fragment encodes putative proteins commonly found within bacteriocin operons, including an ATP-dependent transporter, two immunity-like proteins and the two components of a lantibiotic-type signal-transducing system. The genetic organization of the fragment suggested important gene rearrangements.

Amino Acid Sequence↗
PubMed1999

Synthesis of lactococcin 972, a bacteriocin produced by Lactococcus lactis IPLA 972, depends on the expression of a plasmid-encoded bicistronic operon.

Synthesis of lactococcin 972 is plasmid-encoded. An operon composed of two genes that encode pre-bacteriocin and a putative immunity protein has been identified. The first gene encodes a 91-residue polypeptide that is exported via a sec-dependent system to give the mature 66-aa bacteriocin. The immunity protein is a 563-residue polypeptide with seven potential transmembrane domains. Two transcripts were observed from this region: one comprises the whole operon and is synthesized during the exponential phase of growth while the other, which corresponds just to the bacteriocin structural gene, presents a maximum in exponential cultures but is still present in late-stationary-phase cells.

Amino Acid Sequence↗
PubMed1975

Properties of some bacteriocins produced by Rhizobium trifolii.

Bacteriocins produced by six strains of Rhizobium trifolii were found to be of the relatively low molecular weight, non-phage type. The molecular weights ranged from approximately 1-8 X 105 to 2-0 X 105. All were of protein composition, as indicated by buoyant density (1-32 to 1-34 g/cm3) in CsC1 and by sensitivity to proteolytic enzymes. They were resistant to RNAase but sensitive to DNAase. The six bacteriocins could further be separated into two subgroups on the basis of sensitivity to extremes of pH, binding to filter membranes, activity spectrum on sensitive strains of R. trifolii, and possibly mode of action on sensitive bacteria. Bacteriocin production occurred spontaneously during the early-to mid-exponential phase of bacterial growth in broth culture.

Bacteriocins↗
PubMed1994

Cloning and sequencing of sakP encoding sakacin P, the bacteriocin produced by Lactobacillus sake LTH 673.

Sakacin P is a heat-stable, unmodified peptide bacteriocin produced by Lactobacillus sake LTH 673. The strain was isolated from fermented dry sausages and is well adapted to this habitat. The bacteriocin inhibits the growth of the opportunistic food pathogens Enterococcus faecalis and Listeria monocytogenes and therefore, it may improve the hygienic status of fermented food, i.e. meat products. Oligonucleotide probes were designed from the N-terminal amino acid sequence of sakacin P and used to identify sakP, the structural gene of sakacin P, on the chromosome of L. sake LTH 673. SakP was cloned into Escherichia coli NM554 and the nucleotide sequence of the gene and its adjacent regions were determined. Sakacin P appears to be synthesized as a prepeptide of 61 amino acids which is proteolytically processed to the mature bacteriocin consisting of 43 amino acids. Sequencing of the cloned fragment also revealed the presence of two other open reading frames orfX and orfY, which are located upstream and downstream of sakP, respectively, putatively encoding proteins of 52 and 98 amino acids, respectively. The functions of both ORFs remain unknown. Primer extension analysis revealed a promoter upstream of sakP. Two transcripts of approximately 0.35 and 1.0 kb were detected by Northern hybridization encoding either only sakP, or both sakP and orfY, respectively.

Amino Acid Sequence↗