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PubMed1977

Demonstration of bacteriocin activity in bovine and bison strains of Pasteurella multocida.

Of 33 strains of Pasteurella multocida examined, 14 showed bacteriocin activity and 17 were susceptible to bacteriocin. The activity was increased by about twofold if the cultures were induced with ultraviolet radiation; however, no increase in bacteriocin activity was observed if the potential producer strains were induced with mitomycin C. The bacteriocin activity of potential producer strains was increased if CaCl2 was incorporated in the medium. The patterns of bacteriocin susceptibility indicate that these substances may ultimately contribute to a typing scheme for the species. An extra-chromosomal genetic element was not detected when a potential producer strain was not detected when a potential producer strain was tested by the dye-buoyant density gradient method. This fact suggests that the genetic material responsible for bacteriocin activity in P multocida is located on the host chromosome proper.

Animals↗

PubMed1982

The nucleotide sequence of the bacteriocin promoters of plasmids Clo DF13 and Co1 E1: role of lexA repressor and cAMP in the regulation of promoter activity.

Treatment of cells, harbouring the bacteriocinogenic plasmic Clo DF13 with mitomycin-C, which induces the cellular SOS response, results in a significantly increased transcription of the operon encoding the bacteriocin cloacin DF13, the immunity protein and the lysis protein H. The nucleotide sequences of the promoter regions and N-terminal parts of the bacteriocin genes of Clo DF13, Col E1 and the pMB1 derivative pBR324 have been determined. A comparison of these sequences with those of corresponding regions of the lexA, recA and uvrB genes revealed that the promoter regions of the bacteriocin genes studied contain binding sites for the lexA protein, which is the repressor of the E. coli DNA-repair system. Using both, a thermosensitive lexA host strain and a host with pACYC184 into which the lexA gene had been cloned, we were able to demonstrate, that in vivo the lexA protein is involved in the regulation of bacteriocin synthesis. From the data presented, we conclude that bacteriocin synthesis is controlled at least by the lexA repressor. It has been reported that also catabolite repression might play an essential role in the control of bacteriocin synthesis. Computer analysis of the DNA sequence data indicated that the promoter regions of both, the cloacin DF13 and colicin E1 genes contain potential binding sites for the cyclic AMP-cyclic AMP Receptor Protein complex.

Antibiotics, Antineoplastic↗

PubMed1982

Competitive Dominance by a Bacteriocin-Producing Vibrio harveyi Strain.

Vibrio (Beneckea) harveyi, a bioluminescent marine bacterium, has been shown to produce a bacteriocin-like substance the production of which is mediated by a plasmid. This substance is assumed to be proteinaceous because of its sensitivity to certain proteolytic enzymes. It is stable at low temperatures and can be concentrated by ammonium sulfate precipitation or negative-pressure dialysis. The molecular weight of the bacteriocin was determined to be 2.4 x 10 by molecular exclusion chromatography. Competition experiments indicated that bacteriocin-producing strains predominated over cured variants of the same strain in broth culture experiments. We studied several environmental parameters (pH, salinity, temperature, nutrient concentration) to determine their effects on the competitive advantage bestowed on a bacteriocin-producing strain. Under simulated free-living conditions, no competitive advantage attributable to bacteriocin production was observed. In a simulated enteric habitat, a bacteriocin-producing strain showed dramatic (>90%) inhibition of the sensitive strain within 24 h.

Journal Article↗

PubMed1963

SURVEY OF THE BACTERIOCINES OF ENTEROCOCCI.

Brock, Thomas D. (Indiana University, Bloomington), Barbara Peacher, and Deborah Pierson. A survey of the bacteriocines of enterococci. J. Bacteriol. 86:702-707. 1963.-A survey has been made of bacteriocine production by a wide variety of well-characterized strains of group D streptococci. On the basis of spectrums and sensitivity to chloroform, heat, and proteolytic enzymes, five distinct bacteriocines can be defined. Type 1 is produced by all Streptococcus zymogenes (S. faecalis var. zymogenes) strains, is active against a wide variety of gram-positive bacteria, and is also a hemolysin. Type 2 is produced by some S. liquefaciens (S. faecalis var. liquefaciens) strains, and acts on many enterococci as well as on certain other lactic acid bacteria. Type 3 is produced by certain strains of both S. faecalis and S. faecium, and inhibits a wide variety of group D streptococci, but is inactive against all other lactic acid bacteria tested except Leuconostoc citrovorum. Type 4 is produced by certain S. faecium strains and resembles in certain ways the type 3 activity, but differs from it in other ways. Type 5 has been found to be produced by only one proteolytic strain of S. zymogenes, and this bacteriocine has a very narrow spectrum. The strain that produces this bacteriocine also produces type 1 activity. No strain is sensitive to a bacteriocine of the type it produces.

Bacillus cereus↗

PubMed2002

Purification and partial characterization of bacillocin 490, a novel bacteriocin produced by a thermophilic strain of Bacillus licheniformis.

BACKGROUND: Applications of bacteriocins as food preservatives have been so far limited, principally because of their low antimicrobial activity in foods. Nisin is the only bacteriocin of significant use, but applications are restricted principally because of its very low activity at neutral or alkaline pH. Thus the isolation of new bacteriocins active in foods is desirable. RESULTS: We isolated a Bacillus licheniformis thermophilic strain producing a bacteriocin with some novel features, named here bacillocin 490. This bacteriocin was inactivated by pronase E and proteinase K and was active against closely related Bacillus spp. both in aerobic and in anaerobic conditions. Bactericidal activity was kept during storage at 4 degrees C and was remarkably stable in a wide pH range. The bacteriocin was partially purified by elution after adhesion to cells of the food-isolated strain Bacillus smithii and had a rather low mass (2 KDa). Antimicrobial activity against B. smithii was observed also when this organism was grown in water buffalo milk. CONCLUSIONS: Bacillocin 490 is a novel candidate as a food anti-microbial agent since it displays its activity in milk, is stable to heat treatment and during storage, is active in a wide pH range and has bactericidal activity also at high temperature. These features may allow the use of bacillocin 490 during processes performed at high temperature and as a complementary antimicrobial agent of nisin against some Bacillus spp. in non-acidic foods. The small size suggests its use on solid foods.

Journal Article↗

PubMed2004

Chimeric nature of two plasmids of Hafnia alvei encoding the bacteriocins alveicins A and B.

The complete nucleotide sequences of two bacteriocin-encoding plasmids isolated from Hafnia alvei (pAlvA and pAlvB) were determined. Both plasmids resemble ColE1-type replicons and carry mobilization genes, as well as colicin-like bacteriocin operons. These bacteriocins appear to be chimeras consisting of translocation domains from Tol-dependent colicins, unique binding domains, and killing and immunity domains similar to those of the pore-forming colicin Ia. Just as is found for colicin Ia, these H. alvei bacteriocins (alveicins) lack lysis genes. The alveicins are unusually small at 408 and 358 amino acids for alveicin A and B, respectively, which would make alveicin B the smallest pore-forming bacteriocin yet discovered. The pattern of nucleotide substitution in the alveicins suggests that the dominant forces in the evolution of their killing domains and immunity genes are neutral mutation and random genetic drift rather than diversifying selection, which has been implicated in the evolution of other colicins. Five of six bacteriocinogenic isolates of H. alvei were found to carry plasmids identical to pAlvA. Comparisons of the levels of nucleotide divergence in five housekeeping genes to the levels of divergence in their respective plasmids led us to conclude that pAlvA is transferring laterally through the H. alvei population relatively rapidly.

Amino Acid Sequence↗

PubMed2004

Influence of growth conditions on the production of a bacteriocin by Lactococcus lactis subsp. lactis ST34BR, a strain isolated from barley beer.

Bacteriocin ST34BR, a small polypeptide of 2.9 kDa produced by Lactococcus lactis subsp. lactis ST34BR, inhibits the growth of Enterococcus faecalis, Escherichia coli, Lactobacillus plantarum, Lactobacillus casei, Pseudomonas aeruginosa and Staphylococcus aureus. MRS broth, adjusted to pH 6.0 yielded 6,400 AU/ml, compared to 400 AU/ml recorded in BHI broth, M17 broth, 10% (w/v) soy milk, and 8% and 10% (w/v) molasses. At pH of 4.5 only 800 AU/ml was produced. Based on comparative studies in MRS broth, without organic nitrogen, supplemented with different combinations of tryptone, meat extract and yeast extract, tryptone was identified as the stimulating nitrogen compound. Growth in the presence of 20 g/l glucose, maltose, mannose or sucrose yielded bacteriocin levels of 6,400 AU/ml, whereas the same concentration of lactose and fructose yielded 3,200 AU/ml and 1,600 AU/ml, respectively. No difference in bacteriocin ST34BR activity was recorded in MRS broth supplemented with 2 g/l K2HPO4 and 2 g/l, 5 g/l, 10 g/l or 50 g/l KH2PO4. However, 20 g/l KH2PO4 increased bacteriocin ST34BR production to 12,800 AU/ml. Glycerol at 1g/l to 10 g/l in MRS broth reduced bacteriocin activity to 3,200 AU/ml, whilst 20 g/l and 50 g/l yielded only 1,600 AU/ml. The presence of cyanocobalamin, L-ascorbic acid, thiamine and DL-6,8-thioctic acid in MRS broth at 1.0 ppm, respectively, did not result in increased activity levels.

Animals↗

PubMed2001

Molecular characterisation of aureocin A70, a multi-peptide bacteriocin isolated from Staphylococcus aureus.

Staphylococcus aureus A70 produces a heat-stable bacteriocin designated aureocin A70. Aureocin A70 is encoded within a mobilisable 8 kb plasmid, pRJ6, and is active against Listeria monocytogenes. Experiments of transposition mutagenesis and gene cloning had shown that aureocin A70 production and immunity were associated with the HindIII-A and B fragments of pRJ6. Therefore, a 6332 bp region of the plasmid, encompassing both these fragments, was sequenced using a concatenation DNA sequencing procedure. DNA sequence and genetic analyses revealed the presence of three transcriptional units that appear to be involved in bacteriocin activity. The first transcriptional unit contains a single gene, aurT, which encodes a protein that resembles an ATP-dependent transporter, similar to those involved in lantibiotic export. AurT is required for aureocin A70 production and it appears to be essential for mobilisation of pRJ6. The second putative operon contains two open reading frames (ORFs); the first gene, orfA, is predicted to encode a protein similar to small repressor proteins found in some Archaea, whose function remains to be elucidated. The second gene, orfB, codes for an 138 amino acid residue protein which shares a number of characteristics (high pI and hydrophobicity profile) with proteins associated with immunity, needed for self-protection against bacteriocin. Four other genes are present in the third operon, aurABCD. aurABCD encode four related peptides that are small (30-31 amino acid residues), strongly cationic (pI of 9.85 to 10.04) and highly hydrophobic. Theses peptides also have a high content of small amino acid residues like glycine and alanine, and no cysteine residue. Tn917-lac insertional mutations, which affected aureocin A70 activity, reside within operon aurABCD. Analysis of purified bacteriocin preparations by mass spectrometry demonstrated that all four peptides encoded by aurABCD operon are produced, expressed and excreted without post-translational modifications. Thus, aureocin A70 is a multi-peptide non-lantibiotic bacteriocin, which is transported without processing.

Amino Acid Sequence↗

PubMed1994

Purification and cloning of piscicolin 61, a bacteriocin from Carnobacterium piscicola LV61.

Piscicolin 61, a bacteriocin produced by Carnobacterium piscicola LV61, inhibits the growth of strains of Carnobacterium, Lactobacillus, and Enterococcus. The bacteriocin was purified to homogeneity by ammonium sulfate precipitation and sequential hydrophobic interaction and reversed-phase chromatography. The N-terminal amino acid sequence of piscicolin 61 was determined by Edman degradation. The plasmid-located structural gene encoding piscicolin (psc61) was cloned and sequenced. It encoded a primary translation product of 71 amino acid residues, which is cleaved between amino acid residues 18 and 19 to yield the active bacteriocin. The calculated M(r) from the deduced protein sequence, 5052.6, agreed with that obtained by mass spectrometry. Piscicolin 61 did not show any sequence similarities to other known bacteriocins. However, the leader sequence resembled those of the pediocin-like bacteriocins. Piscicolin 61 may be able to form amphiphilic helices and may thus act on the membrane of sensitive cells.

Amino Acid Sequence↗

PubMed1996

Bacteriocins of Lactobacillus plantarum strains from fermented foods.

Bacteriocin-producing strains may be used as protective cultures to improve the microbial safety of foods. The crude or purified form of these antimicrobial agents may also be applied directly as food preservative. This review gives survey of the different bacteriocins produced by Lactobacillus plantarum isolated from fermented food products with particular emphasis on their genetic and biochemical properties. A number of bacteriocins are produced by L. plantarum. These include plantaricin B, plantaricin BN, plantaricin A, plantaricin C, plantaricin S and T, plantaricin F, plantaricin C19 and SA6 and other unnamed bacteriocins. However, with the exception of plantaricin A, information on the genetic and biochemical characteristics of L. plantarum bacteriocins is still scant.

Bacteriocins↗

PubMed1989

Effect of medium on the bacteriocin production by Klebsiella pneumoniae.

The influence of growth media and media constituents on bacteriocin production by Klebsiella pneumoniae was studied. Among the standard laboratory media used trypticase soy broth (TSB) showed the maximum production and poor yields resulted from growth in peptone water and nutrient broth. A number of peptones differed in their bacteriocin production. Best yields were observed in tryptone and proteose peptone water. Addition of 1% yeast extract to TSB further stimulated bacteriocin production. However, activity was low when glucose, glycine, sodium mercaptoacetate or bile salt mixture were added to the medium. Suppression of synthesis by certain agents as well as inhibition of formed bacteriocin by the others appears to affect the bacteriocin yield. No proteinase activity was detected during the entire incubation period.

Bacteriocins↗

PubMed2003

Influence of growth conditions on bacteriocin production by Brevibacterium linens.

The influence of temperature, NaCl concentration and cheese whey media on growth of Brevibacterium linens ATCC 9175 and production of bacteriocin-like antimicrobial activity was studied. Bacteriocin production and activity were higher at 25 degrees C than at 30 degrees C. No significant growth or production of bacteriocins was observed at 37 degrees C. When bacteriocin production was investigated in media containing different concentrations of NaCl, increased activity was observed in media containing 40 or 80 g l(-1), but not 120 g l(-1) NaCl. The addition of NaCl resulted in a significant increase in specific production rates of bacteriocin-like activity. Antimicrobial activity was also observed by cultivation of B. linens at 25 degrees C in cheese whey media.

Bacteriocins↗

PubMed2003

DNA analysis of the genes encoding acidocin LF221 A and acidocin LF221 B, two bacteriocins produced by Lactobacillus gasseri LF221.

Lactobacillus gasseri LF221, an isolate from the feces of a child, produces two bacteriocins. Standard procedures for molecular techniques were used to locate, clone and sequence the fragments of LF221 chromosomal DNA carrying the acidocin LF221 A and B structural genes, respectively. Sequencing analysis revealed the gene of acidocin LF221 A to be an open reading frame encoding a protein composed of 69 amino acids, including a 16-amino-acid N-terminal extension. The acidocin LF221 B gene was found to encode a 65-amino-acid bacteriocin precursor with a 17-amino-acid N-terminal leader peptide. DNA homology searches showed similarities of acidocin LF221 A to brochocin B, lactococcin N and thermophilin B, whereas acidocin LF221 B exhibited some homology to lactacin F and was virtually identical to gassericin X. The peptides encoded by orfA1 and orfB3 showed characteristics of class II bacteriocins and are suspected to be the complementary peptides of acidocin A and B, respectively. orfA3 and orfB5 are proposed to encode putative immunity proteins for the acidocins. Acidocin LF221 A and acidocin LF221 B are predicted to be members of the two-component class II bacteriocins, where acidocin LF221 A appears to be a novel bacteriocin. L. gasseri LF221 is being developed as a potential probiotic strain and a food/feed preservative. Detailed characterization of its acidocins is an important piece of background information useful in applying the strain into human or animal consumption. The genetic information on both acidocins also enables tracking of the LF221 strain in mixed populations and complex environments.

Amino Acid Sequence↗

PubMed2001

Characterization, production, and purification of carnocin H, a bacteriocin produced by Carnobacterium 377.

Carnocin H, a bacteriocin produced by a Carnobacterium sp., inhibited lactic acid bacteria, clostridia, enterococci, and some Staphylococcus aureus strains. Some strains of Listeria and Pediococcus were also sensitive to carnocin H. The bacteriocin was produced during the late stationary growth phase. Carnocin H was purified by cation exchange chromatography and reverse phase chromatography. Amino acid sequence and composition indicate that carnocin H is a novel bacteriocin belonging to the class II bacteriocins. The bacteriocin consists of approximately 75 amino acid residues with a highly cationic N-terminal containing six succeeding lysines. Activity, as measured by agar diffusion zones, was reduced at increased pH values, levels of indicator bacteria, NaCl, agar, and soy oil.

Amino Acid Sequence↗

PubMed1994

Evidence that dissipation of proton motive force is a common mechanism of action for bacteriocins and other antimicrobial proteins.

While bacteriocins from lactic acid bacteria (LAB) have generated tremendous interest among food microbiologists, they are not unique. The biosphere is awash with antimicrobial proteins such as colicins, defensins, cecropins, and magainins. These proteins share many characteristics. They are low molecular weight, cationic, amphiphilic, tend to aggregate and are benign to the producing organism. In cases where the mode of action has been investigated, the cell membrane appears to be the site of action. There is increasing evidence that bacteriocins from many bacterial genera also share these characteristics. After a brief introduction on the significance of LAB bacteriocins, this review provides some background on proton motive force. Current studies of mechanisms for various bacteriocins are reviewed. Evidence is then introduced that bacteriocins produced by lactic acid bacteria act by the common mechanism of depleting proton motive force. The role and importance of energized membranes in this process is examined. These observations are linked to literature which demonstrates that many other classes of antimicrobial proteins act by the same mechanism. Questions regarding the role of receptor proteins and the physical mechanism by which PMF is depleted remain unresolved.

Amino Acid Sequence↗

PubMed1986

Acinetobacter bacteriocin typing.

A technique for typing Acinetobacter sp. by bacteriocin production has been developed. One hundred and seventy-six cultures from patients in outbreaks, in the community and environmental sources were identified, tested for sensitivity to gentamicin and bacteriocin typed; 154 were A. anitratus and the remainder A.lwoffi. Only one A.lwoffi strain produced bacteriocin. Ten of 22 were sensitive to bacteriocins and could be used as indicators. A close association was found between bacteriocin production and gentamicin resistance: MIC 4 mg/ml. Using six indicator strains 100/104 (96%) gentamicin-resistant strains were typed with nine distinct patterns of inhibition. Overall typability was 65% but 100/176 (56%) fell into only two groups. The technique may be of value in studying the epidemiology of Acinetobacter.

Acinetobacter↗

PubMed2005

Production of bacteriocins by coagulase-negative staphylococci involved in bovine mastitis.

In the present study, 188 coagulase-negative Staphylococcus (CNS) strains were isolated from bovine mastitis cases from 56 different Brazilian dairy herds, located in the Southeast region of the country, and were tested for antimicrobial substance production. Twelve CNS strains (6.4%) exhibited antagonistic activity against a Corynebacterium fimi indicator strain. Most antimicrobial substances were sensitive to proteolytic enzymes suggesting that they might be bacteriocins (Bac). Amongst the CNS producers, six were identified as S. epidermidis, two as S. simulans, two as S. saprophyticus, one as S. hominis and one as S. arlettae. Plasmid profile analysis of these strains revealed the presence of at least one plasmid. The Bac(+) strains presented either no or few antibiotic resistance phenotypes. Three strains were shown to produce a bacteriocin either identical or similar to aureocin A70, a bacteriocin previously isolated from an S. aureus strain isolated from food. The remaining Bac(+) strains produce antimicrobial peptides that seem to be distinct from the best characterised staphylococcal bacteriocins described so far. Some of them were able to inhibit Listeria monocytogenes, an important food-borne pathogen, and several strains of Streptococcus agalactiae associated with bovine mastitis, suggesting a potential use of these bacteriocins either in the prevention or in the treatment of streptococcal mastitis.

Animals↗

PubMed2002

The locus responsible for production of plantaricin S, a class IIb bacteriocin produced by Lactobacillus plantarum LPCO10, is widely distributed among wild-type Lact. plantarum strains isolated from olive fermentations.

The genes plsA and plsB encoding for production of plantaricin S (Pls), a two-peptide bacteriocin produced by Lactobacillus plantarum LPCO10, are commonly distributed among wild-type Lact. plantarum strains isolated from olive fermentations. Among 68 independent isolates from different olive processing plants in South Spain, 15 of them were shown to produce bacteriocins that were active against other lactic acid bacteria, as well as spoilage and pathogenic bacteria. On the basis of PCR amplification and hybridization with specific probes, the Pls operon was detected in all the bacteriocin producer strains but not in the non-producer ones. Purification and subsequent amino acid sequencing of the bacteriocin produced by some of the 15 isolates yielded both the alpha and beta peptides from Pls. These results suggest that bacteriocin production contributes an ecological advantage for the wild-type Lact. plantanum strains in the colonization of the spontaneous, traditional olive fermentation process.

Amino Acid Sequence↗