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ABSTRACT: AIMS: The aim of this study is to evaluate the capacity of three bacteriocin producers, namely Lactococcus lactis subsp. lactis biovar diacetylactis UL719 (nisin Z producer), Lactococcus lactis ATCC 11454 (nisin A producer), and Pediococcus acidilactici UL5 (pediocin PA-1 producer), to grow and produce their active bacteriocins in Macfarlane broth, which mimics the nutrient composition encountered in the human large intestine.s METHODS AND RESULTS: The three bacteriocin-producing strains were grown in Macfarlane broth and in MRS broth. For each strain, the bacterial count, pH drop and production of organic acids and bacteriocins were measured for different period of time. The ability of the probiotic candidates to inhibit Listeria ivanovii HPB 28 in co-culture in Macfarlane broth was also examined. L. lactis subsp. lactis biovar diacetylactis UL719, L. lactis ATCC 11454 and P. acidilactici UL5 were able to grow and produce their bacteriocins in MRS broth and in Macfarlane broth. Each of the three candidates inhibited L. ivanovii HPB 28 and this inhibition activity was correlated with bacteriocin production. The role of bacteriocin production in the inhibition of L. ivanovii in Macfarlane broth was confirmed for P. acidilactici UL5 by using a pediocin non-producer mutant. CONCLUSIONS: The data provides some evidence that these bacteria can produce bacteriocins in a complex medium with carbon source similar to those found in the colon. SIGNIFICANCE AND IMPACT OF THE STUDY: The present study demonstrates the capacity of lactic acid bacteria to produce their bacteriocins in a medium simulating the nutrient composition of the large intestine. © 2012The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.
Journal of Applied Microbiology 11/2012; · 2.34 Impact Factor
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ABSTRACT: Bacteriocin production is a widespread phenomenon among bacteria. Bacteriocins hold great promise for the treatment of diseases caused by pathogenic bacteria and could be used in the future as alternatives to existing antibiotics. The anti-infective potential of bacteriocins for inhibiting pathogens has been shown in various food matrices including cheese, meat, and vegetables. However, their inhibition of pathogens in vivo remains unclear and needs more investigation, due mainly to difficulties associated with demonstrating their health benefits. Many bacteriocins produced by established or potential probiotic organisms have been evaluated as potential therapeutic agents and interesting findings have been documented in vitro as well as in a few in vivo studies. Some recent in vivo studies point to the efficacy of bacteriocin-based treatments of human and animal infections. While further investigation remains necessary before the possibilities for bacteriocins in clinical practice can be described more fully, this review provides an overview of their potential applications to human and veterinary health.
Cellular and Molecular Life Sciences CMLS 10/2012; · 6.57 Impact Factor
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ABSTRACT: Recently, we isolated and reported the antagonism of Paenibacillus polymyxa JB05-01-1 (P. polymyxa JB05-01-1) against Gram-negative bacteria. Here, we provide more insights and attribute the abovementioned antagonism to the production of colistins A and B, which were purified by Amberlite column exchange, C18 column hydrophobicity, superdex 75 16/60 gel filtration chromatography connected to fast protein liquid chromatography and identified by MALDI TOF/TOF, and manual nanospray analysis. The amount of colistin A and colistin B recovered from 500 ml of culture supernatant was about 0.05 mg. The specific activity and the average recovery of the eluted substances were 5,120 AU/mg and 1.1%, respectively. The minimal inhibitory concentrations of the purified colistins against Escherichia coli O157:H7 and Pseudomonas fluorescens LRC R73 were 0.13 and 0.62 μg/ml, respectively.
Archives of Microbiology 10/2011; 194(5):363-70. · 1.43 Impact Factor
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ABSTRACT: Bacteriocins are ribosomally-synthesized peptides or proteins produced by a wide range of bacteria. The antimicrobial activity of this group of natural substances against foodborne pathogenic and spoilage bacteria has raised considerable interest for their application in food preservation. Classifying these bacteriocins in well defined classes according to their biochemical properties is a major step towards characterizing these anti-infective peptides and understanding their mode of action. Actually, the chosen criteria for bacteriocins' classification lack consistency and coherence. So, various classification schemes of bacteriocins resulted various levels of contradiction and sorting inefficiencies leading to bacteriocins belonging to more than one class at the same time and to a general lack of classification of many bacteriocins. Establishing a coherent and adequate classification scheme for these bacteriocins is sought after by several researchers in the field. It is not straightforward to formulate an efficient classification scheme that encompasses all of the existing bacteriocins. In the light of the structural data, here we revisit the previously proposed contradictory classification and we define new structure-based sequence fingerprints that support a subdivision of the bacteriocins into 12 groups. The paper lays down a resourceful and consistent classification approach that resulted in classifying more than 70% of bacteriocins known to date and with potential to identify distinct classes for the remaining unclassified bacteriocins. Identified groups are characterized by the presence of highly conserved short amino acid motifs. Furthermore, unclassified bacteriocins are expected to form an identified group when there will be sufficient sequences.
The Protein Journal 08/2010; 29(6):432-9. · 1.04 Impact Factor
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ABSTRACT: Databases and chemo- and bioinformatics tools that contain genomic, proteomic and functional information have become indispensable for antimicrobial drug research. The combination of chemoinformatics tools, bioinformatics tools and relational databases provides means of analyzing, linking and comparing online search results. The development of computational tools feeds on a diversity of disciplines, including mathematics, statistics, computer science, information technology and molecular biology. The computational approach to antimicrobial agent discovery and design encompasses genomics, molecular simulation and dynamics, molecular docking, structural and/or functional class prediction, and quantitative structure-activity relationships. This article reviews progress in the development of computational methods, tools and databases used for organizing and extracting biological meaning from antimicrobial research.
Drug discovery today 07/2010; 15(13-14):540-6. · 6.63 Impact Factor
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ABSTRACT: BACTIBASE is an integrated open-access database designed for the characterization of bacterial antimicrobial peptides, commonly known as bacteriocins.
For its second release, BACTIBASE has been expanded and equipped with additional functions aimed at both casual and power users. The number of entries has been increased by 44% and includes data collected from published literature as well as high-throughput datasets. The database provides a manually curated annotation of bacteriocin sequences. Improvements brought to BACTIBASE include incorporation of various tools for bacteriocin analysis, such as homology search, multiple sequence alignments, Hidden Markov Models, molecular modelling and retrieval through our taxonomy Browser.
The provided features should make BACTIBASE a useful tool in food preservation or food safety applications and could have implications for the development of new drugs for medical use. BACTIBASE is available at http://bactibase.pfba-lab-tun.org.
BMC Microbiology 01/2010; 10:22. · 3.04 Impact Factor
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ABSTRACT: Oudneya africana R. Br. (Brassicaceae), a wild-growing plant in the arid region of Tunisia, is used in ethno-medicinal treatment of microbial infections. Validation of ethno-therapeutic claims pertaining to the plant was sought by investigating its antimicrobial activity. A proteinaceous extract of the seeds, called AS-3000, showed activity against various organisms including L. monocytogenes, E. coli, B. subtilis, E. hirae, P. aeruginosa, S. aureus and C. albicans. Extract AS-3000 exhibited a synergistic effect against L. ivanovii when combined with vancomycin or chloramphenicol. The post-antibiotic inhibitory effect of the ampicillin/AS-3000 combination was 2.3-fold greater than for the antibiotic alone. The mode of action of AS-3000 on Listeria and Escherichia was visible using SEM. These results support the use of O. africana for treating microbial infections.
Microbiology and Immunology 12/2009; 53(12):658-66. · 1.30 Impact Factor
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ABSTRACT: The anti-listerial effect of pediocin PA-1 and its producing strain, Pediococcus acidilactici UL5, was investigated in vivo using an ICR mouse model. The effect of intra-gastric administration of a single dose of P. acidilactici UL5 (4 x 10(10) CFU/animal) on the propagation of Listeria monocytogenes LSD348 in intestine, liver and spleen was negligible. P. acidilactici UL5 did not appear competitive with the mouse intestinal flora and was not detectable in fecal samples collected two days after administration. However, double-agar-layer activity assay showed the ability of P. acidilactici UL5 colonies recovered from fecal samples one day after administration to produce pediocin PA-1 and inhibit L. monocytogenes. Moreover, repeated doses (250 microg/day for three consecutive days) of purified pediocin PA-1 provided up to 2-log reductions in fecal listerial counts compared to the infected control group and slowed pathogen translocation into the liver and spleen, leading to the disappearance of L. monocytogenes infection in these two organs within six days. Neither P. acidilactici UL5 nor ingested purified pediocin PA-1 had any negative effect on feed intake or body weight development. Pediocin PA-1 did not affect the composition of the mouse intestinal flora, suggesting a potential advantage over other inhibitory agents as a prophylactic measure against L. monocytogenes.
International journal of food microbiology 06/2009; 133(3):225-33. · 3.01 Impact Factor
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ABSTRACT: Seed extracts of three plant species that grow wild in the arid regions of Tunisia, Juniperus phoenicea L. (Cupressaceae), Pistacia atlantica Desf. (Anacardiaceae), and Oudneya africana R. Br. (Brassicaceae), were examined for antimicrobial activity against bacterial food pathogens. Aqueous extracts were prepared and then precipitated with methanol or acetone. Extracted acetone fractions (pH 7.2) showed powerful antimicrobial activity, especially against Listeria monocytogenes, Listeria innocua, and Listeria ivanovii (Gram-positive) and were also active against Gram-negative strains Escherichia coli and Pseudomonas aeruginosa. Extracts selected for high antimicrobial activity were stable in the presence of organic solvents (chloroform, hexane, acetonitrile, methanol, and acetone), and withstand thermal treatments up to 100°C for 30 min. L. monocytogenes LSD530 and E. coli ATCC 25922 appeared to be inhibited by Juniperus and Pistacia extracts with a minimum concentration of 1.56 and 3. 12 mg/mL, respectively. This study established the potential of medicinal plants growing wild in arid regions of Tunisia as a source of antimicrobial agents.
04/2009; 47(5):452-457.
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ABSTRACT: Plants produce small cysteine-rich antimicrobial peptides as an innate defense against pathogens. Based on amino acid sequence homology, these peptides were classified mostly as alpha-defensins, thionins, lipid transfer proteins, cyclotides, snakins and hevein-like. Although many antimicrobial plant peptides are now well characterized, much information is still missing or is unavailable to potential users. The compilation of such information in one centralized resource, such as a database would therefore facilitate the study of the potential these peptide structures represent, for example, as alternatives in response to increasing antibiotic resistance or for increasing plant resistance to pathogens by genetic engineering. To achieve this goal, we developed a new database, PhytAMP, which contains valuable information on antimicrobial plant peptides, including taxonomic, microbiological and physicochemical data. Information is very easy to extract from this database and allows rapid prediction of structure/function relationships and target organisms and hence better exploitation of plant peptide biological activities in both the pharmaceutical and agricultural sectors. PhytAMP may be accessed free of charge at http://phytamp.pfba-lab.org.
Nucleic Acids Research 11/2008; 37(Database issue):D963-8. · 8.03 Impact Factor
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ABSTRACT: The aim of this work was to study the effect of antimicrobial peptides: divergicin M35 and nisin A on Listeria monocytogenes LSD 530 potassium (K+) channels: ATP-sensitive (K ATP), calcium-activated (BK Ca), and depolarization-activated (Kv) types. Increase on K+ efflux and inhibition of cellular growth were observed after adding K+ channel activators pinacidil, NS1619, and cromakalim to divergicin M35. Increase in K+ efflux from log-phase cells was about 18 +/- 1.1, 11 +/- 0.63, and nmol mg(-1) of cell dry weight (CDW) for pinacidil and NS1619, respectively, over the efflux obtained with divergicin M35 alone. Increases in K+ efflux obtained by adding the same K+ channel activators to nisin A fit a completely different profile. Divergicin M35 activates K+ channels, particularly of the Kv and BK Ca types and to a lesser extent the K ATP type, causing K+ efflux and consequently cell death.
Current Microbiology 07/2008; 56(6):609-12. · 1.82 Impact Factor
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ABSTRACT: Pediocin PA-1 production by Pediococcus acidilactici UL5 cells immobilized in kappa-carrageenan/locust bean gum gel beads was studied during repeated-cycle batch (RCB) culture with pH control in Man Rogosa and Sharpe (MRS) broth supplemented with 1% glucose and whey permeate (SWP) medium. The pediocin PA-1 production by free P. acidilactici cells pH-controlled batch culture has reached 2048 and 4096 AU ml(-1) after 11 and 12 h of incubation, with volumetric productivities of 187 and 342 AU ml(-1) h(-1) in SWP and MRS media, respectively. In RCB culture, immobilized cells reached a maximum concentration of 7.3+/-0.2 x 10(10) and 4.3+/-0.9 x 10(10) cfu g(-1) of beads in MRS and SWP media, respectively. The maximum pediocin PA-1 activity obtained during RCB fermentation was 4096 AU ml(-1); it was attained after only 0.75 and 2 h of incubation in MRS and SWP media, respectively. The corresponding volumetric productivities were 5461 and 2048 AU ml(-1) h(-1). Pediocin PA-1 production in the RCB culture was highly stable over 12 fermentation cycles carried out over 3 d in SWP media.
Journal of Bioscience and Bioengineering 06/2008; 105(5):513-7. · 1.79 Impact Factor
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ABSTRACT: The exponential growth of research in molecular biology has brought concomitant proliferation of databases for stocking its findings. A variety of protein sequence databases exist. While all of these strive for completeness, the range of user interests is often beyond their scope. Large databases covering a broad range of domains tend to offer less detailed information than smaller, more specialized resources, often creating a need to combine data from many sources in order to obtain a complete picture. Scientific researchers are continually developing new specific databases to enhance their understanding of biological processes.
In this article, we present the implementation of a new tool for protein data analysis. With its easy-to-use user interface, this software provides the opportunity to build more specialized protein databases from a universal protein sequence database such as Swiss-Prot. A family of proteins known as bacteriocins is analyzed as 'proof of concept'.
SciDBMaker is stand-alone software that allows the extraction of protein data from the Swiss-Prot database, sequence analysis comprising physicochemical profile calculations, homologous sequences search, multiple sequence alignments and the building of new and more specialized databases. It compiles information with relative ease, updates and compares various data relevant to a given protein family and could solve the problem of dispersed biological search results.
BMC Bioinformatics 02/2008; 9:121. · 2.75 Impact Factor
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ABSTRACT: The susceptibility of 11 strains of Listeria monocytogenes to divergicin M35, a bacteriocin produced by Carnobacterium divergens strain M35, and to aqueous extracts of garlic, onion, oregano, red chili and black pepper at 30 and 10C, was evaluated using a microdilution assay. The susceptibility of divergicin-resistant strains to combinations of these agents was also evaluated. Three strains were resistant to divergicin M35 (>500 µg/mL) at 30C but were more susceptible at 10C. Garlic gave the most inhibitory plant extract, followed by onion, while oregano, red chili and black pepper extracts were less active at both temperatures. Garlic extract and divergicin M35 combined or with other extracts increased inhibitory activity against the divergicin-resistant strains. The garlic/divergicin combination was the most effective at inhibiting these strains and was bactericidal at both temperatures. Log-phase cells were the most susceptible to the garlic/divergicin combination. Stationary-phase cells were much more resistant at both incubation temperatures. Furthermore, the effect of the garlic/divergicin combination at inhibiting divergicin-resistant L. monocytogenes in a food system was also studied using cold-smoked salmon as a food model. Results indicated that this combination could efficiently reduce the viability of L. monocytogenes in smoked salmon stored at 10C.PRACTICAL APPLICATIONSThere is increasing popularity worldwide for chemical preservative-free, ready-to-eat and minimally processed seafood with low salt, fat and sugar content. Bacteriocins produced from lactic acid bacteria can have a potential application to prolong the shelf life of cold-smoked salmon. Also, plant and spice extracts have been shown to contain antibacterial substances with potential for application in foods. Thus, this research explores the combination of divergicin M35, a bacteriocin produced by Carnobacterium divergens strain M35, and aqueous extracts of garlic, onion, oregano, red chili and black pepper to inhibit Listeria monocytogenes and to prolong the shelf life of cold-smoked salmon.
Journal of Food Quality 01/2008; 31(1):13 - 33. · 0.54 Impact Factor
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ABSTRACT: Bacteriocins are very diverse group of antimicrobial peptides produced by a wide range of bacteria and known for their inhibitory activity against various human and animal pathogens. Although many bacteriocins are now well characterized, much information is still missing or is unavailable to potential users. The assembly of such information in one central resource such as a database would therefore be of great benefit to the exploitation of these bioactive molecules in the present context of increasing antibiotic resistance and natural bio-preservation need.
In the present paper, we present the development of a new and original database BACTIBASE that contains calculated or predicted physicochemical properties of 123 bacteriocins produced by both Gram-positive and Gram-negative bacteria. The information in this database is very easy to extract and allows rapid prediction of relationships structure/function and target organisms of these peptides and therefore better exploitation of their biological activity in both the medical and food sectors.
The BACTIBASE database is freely available at http://bactibase.pfba-lab.org, web-based platform enabling easy retrieval, via various filters, of sets of bacteriocins that will enable detailed analysis of a number of microbiological and physicochemical data.
BMC Microbiology 02/2007; 7:89. · 3.04 Impact Factor
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ABSTRACT: We have previously demonstrated that Lactobacillus paracasei NCC2461 may help to prevent cow's milk allergy in mice by inducing oral tolerance to beta-lactoglobulin (BLG). To investigate the mechanisms involved in this beneficial effect, we examined the possibility that L. paracasei induces tolerance by hydrolyzing BLG-derived peptides and liberating peptides that stimulate interleukin-10 (IL-10) production. L. paracasei peptidases have been shown to hydrolyze tryptic-chymotryptic peptides from BLG, releasing numerous small peptides with immunomodulating properties. We have now shown that acidic tryptic-chymotryptic peptides stimulate splenocyte proliferation and gamma interferon (IFN-gamma) production in vitro. Hydrolysis of these peptides with L. paracasei peptidases repressed the lymphocyte stimulation, up-regulated IL-10 production, and down-regulated IFN-gamma and IL-4 secretion. L. paracasei NCC2461 may therefore induce oral tolerance to BLG in vivo by degrading acidic peptides and releasing immunomodulatory peptides stimulating regulatory T cells, which function as major immunosuppressive agents by secreting IL-10.
Clinical and Diagnostic Laboratory Immunology 04/2004; 11(2):266-71. · 2.51 Impact Factor
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ABSTRACT: In this study, the effect of Lactobacillus paracasei (NCC 2461), Lactobacillus johnsonii (NCC 533) and Bifidobacterium lactis Bb12 (NCC 362) on the induction and maintenance of oral tolerance to bovine beta-lactoglobulin (BLG) was investigated in mice. Germfree mice were monocolonized with one of the three strains before oral administration of whey protein to induce tolerance. Mice were then injected with BLG and sacrificed 28 or 50 days after whey protein feeding for humoral and cellular response measurement. Conventional and germfree mice were used as controls. Both humoral and cellular responses were better suppressed in conventional mice than in germfree and monoassociated mice throughout the experiment and better suppressed in L. paracasei-associated mice than in mice colonized with B. lactis or L. johnsonii. The latter two mono-associations suppressed humoral responses only partially and cellular responses not at all. This study provides evidence that probiotics modulate the oral tolerance response to BLG in mice. The mono-colonization effect is strain-dependant, the best result having been obtained with L. paracasei.
Clinical and Diagnostic Laboratory Immunology 10/2003; 10(5):787-92. · 2.51 Impact Factor
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ABSTRACT: From the nisZ gene sequence, a non-radioactive digoxigenin-labeled DNA probe, was tested for detection of nisin-producing strains using polymerase chain reaction amplification. The digoxigenin-labeled DNA probe clearly discriminated between nisin-producing and non-producing strains with a high degree of sensitivity and specificity. By agarose gel electrophoresis, 1.4 ng of nisin DNA was detected using the digoxigenin-labeled DNA probe compared with 11 ng using direct polymerase chain reaction amplification. A colony hybridization method using digoxigenin-labeled DNA to selectively detect nisinogenic bacteria showed that the nis-probe was specific and did not react with any other non-bacteriocinogenic and non-nisinogenic strains.
FEMS Microbiology Letters 01/1999; 171(1):43 - 48. · 2.04 Impact Factor
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ABSTRACT: A one-step purification procedure for purifying pediocin PA-1, a class IIa bacteriocin produced by Pediococcus acidilactici UL5, was developed based on column immunoaffinity chromatography with specific antipediocin PA-1 polyclonal antibodies coupled to cyanogen bromide-activated SepharoseTM. About 13.3 microg/mL purified pediocin PA-1 was obtained from 15 mL P. acidilactici UL5 culture supernatant, as measured by enzyme-linked immunosorbent assay. The specific activity and average recovery of the eluted pediocin PA-1 were about 6602 AU/mg and 53.3%, respectively. This is the first report of successful purification of pediocin PA-1 by immunoaffinity using pediocin PA-1-specific polyclonal antibodies.
Journal of AOAC International 91(4):828-32. · 1.20 Impact Factor
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ABSTRACT: Cow milk proteins, particularly β-lactoglobulin (BLG) are a leading cause of food allergy in children. In vivo, gastrointestinal hydrolysis of milk proteins decreases their allergenicity, but the intestinal microbiota also contributes to their breakdown. This study investigated the effect of hydrolysis of BLG-derived tryptic-chymotryptic (TC) peptides by Bifidobacterium lactis NCC362 enzymes, on their allergenicity. B. lactis enzymes have been shown to hydrolyze both acidic and basic peptide fractions isolated from tryptic-chymotryptic hydrolysate, but not whole proteins. The IgE binding capacity of acidic TC peptides was reduced by B. lactis peptidases-driven hydrolysis. This is partly explained by the breakdown of known allergenic peptides. Moreover, the resulting peptide fragments significantly up-regulated IFN-γ and IL-10 production and down-regulated IL-4 secretion by murine splenocytes. These results indicate that B. lactis NCC362 could be a potential probiotic for preventing cow's milk allergy through hydrolysis of the allergenic portion of BLG and the release of peptides which down-regulate the allergic immune response, but further studies using living bacteria are needed to confirm these data.
International Dairy Journal.
