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Applied Microbiology and Biotechnology Apr 2016Lactic acid bacteria (LAB) constitute a heterogeneous group of microorganisms that produce lactic acid as the major product during the fermentation process. LAB are... (Review)
Review
Lactic acid bacteria (LAB) constitute a heterogeneous group of microorganisms that produce lactic acid as the major product during the fermentation process. LAB are Gram-positive bacteria with great biotechnological potential in the food industry. They can produce bacteriocins, which are proteinaceous antimicrobial molecules with a diverse genetic origin, posttranslationally modified or not, that can help the producer organism to outcompete other bacterial species. In this review, we focus on the various types of bacteriocins that can be found in LAB and the organization and regulation of the gene clusters responsible for their production and biosynthesis, and consider the food applications of the prototype bacteriocins from LAB. Furthermore, we propose a revised classification of bacteriocins that can accommodate the increasing number of classes reported over the last years.
Topics: Bacterial Proteins; Bacteriocins; Bifidobacterium; Fermentation; Food Microbiology; Gene Expression; Lactic Acid; Lactobacillaceae; Multigene Family
PubMed: 26860942
DOI: 10.1007/s00253-016-7343-9 -
Journal of Oleo Science Apr 2022Lactobacilli are commonly found in raw and fermented foods. These bacteria are of common interest because of their capability of bacteriocin production. Bacteriocins are...
Lactobacilli are commonly found in raw and fermented foods. These bacteria are of common interest because of their capability of bacteriocin production. Bacteriocins are compounds that may be used as natural preservatives in place of chemical additives. In the present study five different samples of poultry, meat and pickle were used to isolate lactic acid bacteria (LAB) by using the MRS culture medium. Antibacterial activity was checked against Pseudomonas aeruginosa, E. coli and Staphylococcus aureus. Five strains from the poultry meat and six strains from pickle had shown antibacterial activity out of eight strains against pathogenic bacteria. Three strains of poultry meat i.e. M3, M7, M11, had shown antibacterial activity against all three indicator strains. While one strain M1 was active against Pseudomonas aeruginosa and E. coli but it was found not to be active against Staphylococcus aureus. E. coli and Staphylococcus aureus were not susceptible to M2. In the case of pickle strains H1, H2, NAT1, NAT2, were found to be active against Pseudomonas aeruginosa and E. coli but Staphylococcus aureus was not susceptible to bacteriocins of these strains. NAT3 and SHZa strains showed antibacterial activity against all the three used pathogens. The highest activity (6 mm) had shown by the lNAT3 strain of pickle against Pseudomonas aeruginosa. The least antimicrobial activity had shown by SHZa strain. M3 had an inhibition zone of 5 mm against Pseudomonas aeruginosa. M11 had an inhibition zone of 5 mm against E. coli. Bacteriocins of all isolates were sensitive towards enzyme pepsin showing their proteinaceous nature. Detection of the bacteriocin gene by PCR the strains M2, M7 were amplified for Curvacin and plantaricin genes. From current study, it is concluded that different species of Lactobacilli can be used as antibacterial tool against common bacterial pathogens.
Topics: Anti-Bacterial Agents; Bacteria; Bacteriocins; Escherichia coli; Lactobacillus
PubMed: 35283412
DOI: 10.5650/jos.ess21424 -
Journal of Infection and Public Health Dec 2021Bacteriocins are proteins or peptides synthesized by bacteria that show inhibitory or killing activities against various bacteria. Bacteriocins are mainly considered for...
BACKGROUND
Bacteriocins are proteins or peptides synthesized by bacteria that show inhibitory or killing activities against various bacteria. Bacteriocins are mainly considered for effective alternatives to different commercial antibiotics, preservatives in the food and pharmaceutical industries.
OBJECTIVES
To screen and analyze novel bacteriocin-producing bacteria from the fermented food shidal for antibacterial activity against food pathogens and their molecular interactions studied through computationally.
METHODS
In this study, a strain Lactobacillus plantarum LA21 was isolated from the fermented food shidal identified based on morphological, biochemical, and 16S rDNA gene sequencing. The potent bacterium was subjected to improve bacteriocins production and characterized. Antimicrobial activity against drug-resistant bacteria and minimum inhibitory concentration (MIC) were determined. The bacteriocin was treated with proteolytic enzymes, and the mechanism of action on food pathogens was analyzed. Molecular docking studies were carried out as GLIDE module in the maestro tool of Schrodinger Software.
RESULTS
Bacteriocin was effective against pathogens such as Bacillus pumilus, Bacillus amyloliquefaciens, Staphylococcus aureus, and Listeria monocytogenes, with the most negligible MIC value was detected in L. monocytogenes. Furthermore, the depleted viability of bacterial cells indicated bacteriocin-induced cell lysis in L. monocytogenes via bactericidal activity. In addition, proteolytic enzyme digested bacteriocins revealed bacteriocin-like substances. Finally, molecular docking was performed to study the interactions between the targets and bacteriocins, results in relative intense contact with minimally 3 Å distance.
CONCLUSIONS
The characteristic features of these bacteriocin-like molecules revealed that L. plantarum LA21 is a novel bacteriocin-producing bacterial strain to prepare novel antimicrobial drugs, feed additives or preservatives for future use in livestock and food industries.
Topics: Anti-Bacterial Agents; Bacteriocins; Lactobacillus plantarum; Listeria monocytogenes; Microbial Sensitivity Tests; Molecular Docking Simulation
PubMed: 34740552
DOI: 10.1016/j.jiph.2021.09.029 -
Archives of Microbiology Jul 2021A bacteriocin from Bacillus subtilis (MK733983) originated from ethnomedicinal plant was purified using Preparative RP-HPLC. The HPLC fraction eluted with 65%...
A bacteriocin from Bacillus subtilis (MK733983) originated from ethnomedicinal plant was purified using Preparative RP-HPLC. The HPLC fraction eluted with 65% acetonitrile showed the highest antimicrobial activity with Mycobacterium smegmatis as an indicator. Its specific activity and purification fold increased by 70.5% and 44%, respectively, compared to the crude bacteriocin. The bacteriocin showed stability over a wide range of pH (3.0-8.0) and preservation (- 20 °C and 4 °C), also thermal stability up to 80 °C for 20 min. Its proteinaceous nature was confirmed with complete loss of activity on its treatment with Trypsin, Proteinase K, and α-Chymotrypsin. Nevertheless, the bacteriocin retained up to 45% activity with Papainase treatment and was unaffected by salivary Amylase. It maintained ~ 95% activity on UV exposure up to 3 h and its activity was augmented by ethyl alcohol and metal ions like Fe and Mn. Most of the common organic solvents, general surfactants, preservatives, and detergents like Sulfobetaine-14, Deoxy-cholic-acid did not affect the bacteriocin's action. Its molecular weight was estimated to be 3.4KDa by LC-ESI-MS/MS analysis. The bacteriocin is non-hemolytic and exhibited a broad inhibition spectrum with standard strains of Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli and Chromobacterium violaceum with MICs ranging 0.225 ± 0.02-0.55 ± 0.05 mg/mL. Scanning Electron Microscopy showed cell annihilation with pores in cell membranes of S. aureus and P. aeruginosa treated with the bacteriocin, implicating bactericidal mode of action. These promising results suggest that the bacteriocin is significant and has wide-ranging application prospects.
Topics: Anti-Bacterial Agents; Bacillus subtilis; Bacteria; Bacteriocins; Hydrogen-Ion Concentration; Microbial Sensitivity Tests; Molecular Weight; Plants, Medicinal; Tandem Mass Spectrometry; Temperature
PubMed: 33544157
DOI: 10.1007/s00203-020-02173-7 -
The cost and benefit of quorum sensing-controlled bacteriocin production in Lactobacillus plantarum.Journal of Evolutionary Biology Jan 2020Bacteria eliminate competitors via 'chemical warfare' with bacteriocins. Some species appear to adjust bacteriocin production conditionally in response to the social...
Bacteria eliminate competitors via 'chemical warfare' with bacteriocins. Some species appear to adjust bacteriocin production conditionally in response to the social environment. We tested whether variation in the cost and benefit of producing bacteriocins could explain such conditional behaviour, in the bacteria Lactobacillus plantarum. We found that: (a) bacterial bacteriocin production could be upregulated by either the addition of a synthetic autoinducer peptide (PLNC8IF; signalling molecule), or by a plasmid which constitutively encodes for the production of this peptide; (b) bacteriocin production is costly, leading to reduced growth when grown in poor and, to a lesser extent, in rich media; (c) bacteriocin production provides a fitness advantage, when grown in competition with sensitive strains; and (d) the fitness benefits provided by bacteriocin production are greater at higher cell densities. These results show how the costs and benefits of upregulating bacteriocin production can depend upon abiotic and biotic conditions.
Topics: Bacteriocins; Cost-Benefit Analysis; Lactobacillus plantarum; Quorum Sensing; Up-Regulation
PubMed: 31610055
DOI: 10.1111/jeb.13551 -
Journal of Bacteriology Jun 2023Most Pseudomonas aeruginosa strains produce bacteriocins derived from contractile or noncontractile phage tails known as R- and F-type pyocins, respectively. These...
Most Pseudomonas aeruginosa strains produce bacteriocins derived from contractile or noncontractile phage tails known as R- and F-type pyocins, respectively. These bacteriocins possess strain-specific bactericidal activity against P. aeruginosa and likely increase evolutionary fitness through intraspecies competition. R-type pyocins have been studied extensively and show promise as alternatives to antibiotics. Although they have similar therapeutic potential, experimental studies on F-type pyocins are limited. Here, we provide a bioinformatic and experimental investigation of F-type pyocins. We introduce a systematic naming scheme for genes found in R- and F-type pyocin operons and identify 15 genes invariably found in strains producing F-type pyocins. Five proteins encoded at the 3' end of the F-type pyocin cluster are divergent in sequence and likely determine bactericidal specificity. We use sequence similarities among these proteins to define eleven distinct F-type pyocin groups, five of which had not been previously described. The five genes encoding the variable proteins associate in two modules that have clearly reassorted independently during the evolution of these operons. These proteins are considerably more diverse than the specificity-determining tail fibers of R-type pyocins, suggesting that F-type pyocins may have emerged earlier. Experimental studies on six F-type pyocin groups show that each displays a distinct spectrum of bactericidal activity. This activity is strongly influenced by the lipopolysaccharide O-antigen type, but other factors also play a role. F-type pyocins appear to kill as efficiently as R-type pyocins. These studies set the stage for the development of F-type pyocins as antibacterial therapeutics. Pseudomonas aeruginosa is an opportunistic pathogen that causes antibiotic-resistant infections with high mortality rates, particularly in immunocompromised individuals and cystic fibrosis patients. Due to the increasing frequency of multidrug-resistant P. aeruginosa infections, there is great need for the development of alternative therapeutics. In this study, we investigate one such potential therapeutic: F-type pyocins, which are bacteriocins naturally produced by P. aeruginosa that resemble noncontractile phage tails. We show that they are potent killers of P. aeruginosa and identify their probable bactericidal specificity determinants, which opens up the possibility of engineering them to precisely target strains of pathogenic bacteria. The resemblance of F-type pyocins to well-characterized phage tails will greatly facilitate their development into effective antibacterials.
Topics: Humans; Pyocins; Pseudomonas aeruginosa; Bacteriocins; Anti-Bacterial Agents; Bacteriophages
PubMed: 37260386
DOI: 10.1128/jb.00029-23 -
Metabolic Engineering Nov 2021Bacteriocins are antimicrobial peptides produced by bacteria to inhibit competitors in their natural environments. Some of these peptides have emerged as commercial food...
Bacteriocins are antimicrobial peptides produced by bacteria to inhibit competitors in their natural environments. Some of these peptides have emerged as commercial food preservatives and, due to the rapid increase in antibiotic resistant bacteria, are also discussed as interesting alternatives to antibiotics for therapeutic purposes. Currently, commercial bacteriocins are produced exclusively with natural producer organisms on complex substrates and are sold as semi-purified preparations or crude fermentates. To allow clinical application, efficacy of production and purity of the product need to be improved. This can be achieved by shifting production to recombinant microorganisms. Here, we identify Corynebacterium glutamicum as a suitable production host for the bacteriocin pediocin PA-1. C. glutamicum CR099 shows resistance to high concentrations of pediocin PA-1 and the bacteriocin was not inactivated when spiked into growing cultures of this bacterium. Recombinant C. glutamicum expressing a synthetic pedACD operon releases a compound that has potent antimicrobial activity against Listeria monocytogenes and Listeria innocua and matches size and mass:charge ratio of commercial pediocin PA-1. Fermentations in shake flasks and bioreactors suggest that low levels of dissolved oxygen are favorable for production of pediocin. Under these conditions, however, reduced activity of the TCA cycle resulted in decreased availability of the important pediocin precursor l-asparagine suggesting options for further improvement. Overall, we demonstrate that C. glutamicum is a suitable host for recombinant production of bacteriocins of the pediocin family.
Topics: Bacteriocins; Corynebacterium glutamicum; Listeria; Pediocins
PubMed: 34492380
DOI: 10.1016/j.ymben.2021.09.002 -
The Journal of Biological Chemistry Nov 2022Enterocin K1 (EntK1), a bacteriocin that is highly potent against vancomycin-resistant enterococci, depends on binding to an intramembrane protease of the site-2...
Enterocin K1 (EntK1), a bacteriocin that is highly potent against vancomycin-resistant enterococci, depends on binding to an intramembrane protease of the site-2 protease family, RseP, for its antimicrobial activity. RseP is highly conserved in both EntK1-sensitive and EntK1-insensitive bacteria, and the molecular mechanisms underlying the interaction between RseP and EntK1 and bacteriocin sensitivity are unknown. Here, we describe a mutational study of RseP from EntK1-sensitive Enterococcus faecium to identify regions of RseP involved in bacteriocin binding and activity. Mutational effects were assessed by studying EntK1 sensitivity and binding with strains of naturally EntK1-insensitive Lactiplantibacillus plantarum-expressing various RseP variants. We determined that site-directed mutations in conserved sequence motifs related to catalysis and substrate binding, and even deletion of two such motifs known to be involved in substrate binding, did not abolish bacteriocin sensitivity, with one exception. A mutation of a highly conserved asparagine, Asn359, in the extended so-called LDG motif abolished both binding of and killing by EntK1. By constructing various hybrids of the RseP proteins from sensitive E. faecium and insensitive L. plantarum, we showed that the extracellular PDZ domain is the key determinant of EntK1 sensitivity. Taken together, these data may provide valuable insight for guided construction of novel bacteriocins and may contribute to establishing RseP as an antibacterial target.
Topics: Bacteriocins; Escherichia coli Proteins; Endopeptidases; Membrane Proteins; Enterococcus faecium; Metalloproteases
PubMed: 36244452
DOI: 10.1016/j.jbc.2022.102593 -
Virulence Dec 2022can cause severe infections in pigs and humans. The tonsils of pigs are major niches for , and different serotypes of can be found in the same tonsil. Pig tonsil...
can cause severe infections in pigs and humans. The tonsils of pigs are major niches for , and different serotypes of can be found in the same tonsil. Pig tonsil colonization by is believed to be an important source of infection for humans and pigs. However, how competes for a stable tonsil niche is unknown. Here, we found that strain WUSS351, isolated from a healthy pig tonsil, is virulent and multidrug-resistant. The ABC transporter system SstFEG, conferring resistance to bacitracin, was reported to confer a competitive survival advantage . In addition, strain WUSS351 has several antimicrobial systems, including a novel type VII secretion system (T7SS), lantibiotic bacteriocin, and lactococcin972-like bacteriocin Lcn351. Bacterial competition experiments demonstrated T7SS-mediated cell contact-dependent antagonism of . Antibacterial activity analysis and 16S rRNA gene sequencing of the culture-independent and culture-dependent pig tonsillar microbiome revealed that Lcn351 mainly targets , one of the core microbiomes in pig tonsils. Taken together, our results revealed the mechanism of the stable persistence of in the tonsil niche, which might have important implications for epidemiology, potentially influencing strain prevalence and disease progression.
Topics: Animals; Anti-Bacterial Agents; Bacteriocins; Palatine Tonsil; RNA, Ribosomal, 16S; Streptococcus suis; Swine
PubMed: 35481413
DOI: 10.1080/21505594.2022.2069390 -
Applied and Environmental Microbiology Mar 2019LA327, isolated from the large intestine tissue in humans, is a bacteriocinogenic strain with two kinds of class IIb bacteriocin structural genes, i.e., those for...
LA327, isolated from the large intestine tissue in humans, is a bacteriocinogenic strain with two kinds of class IIb bacteriocin structural genes, i.e., those for gassericin T (GT) and acidocin LF221A (Acd LF221A). In this study, DNA sequencing of the genes for GT and Acd LF221A from LA327 revealed that the amino acid sequences for GT corresponded with those for GT genes, except for GatK (histidine kinase). However, Acd LF221A genes had analogues which differed in at least one amino acid residue, to encode a class IIb bacteriocin designated gassericin S (GS). The LA327 strain retained antimicrobial activity after the deletion of the GT structural genes (); however, both GS and GT activities were lost by deletion of the putative ABC transporter gene (). This indicates that the LA327 strain produces GS and GT and that GS secretion is performed via GT genes with the inclusion of Homologous expression using deletion mutants of GS and GT, each containing a single peptide, elucidated that GS (GasAX) and GT (GatAX) showed synergistic activity as class IIb bacteriocins and that no synergistic activity was observed between GS and GT peptides. The molecular mass of GS was estimated to be theoretical ca. 5,400 Da by activity assay after SDS-PAGE, clarifying that GS was actually expressed as an active class IIb bacteriocin. Furthermore, the stability of expressed GS to pH, heat, and protease was determined. Bacteriocins are regarded as potential alternatives for antibiotics in the absence of highly resistant bacteria. In particular, two-peptide (class IIb) bacteriocins exhibit the maximum activity through the synergy of two components, and their antimicrobial spectra are known to be relatively wide. However, there are few reports of synergistic activity of class IIb bacteriocins determined by isolation and purification of individual peptides. Our results clarified the interaction of each class IIb component peptide for GT and GS via the construction of homologous mutants, which were not dependent on the purification. These data may contribute to understanding the mechanisms of action by which class IIb bacteriocins exhibit wide antibacterial spectra.
Topics: Amino Acid Sequence; Bacterial Proteins; Bacteriocins; Drug Stability; Hydrogen-Ion Concentration; Lactobacillus gasseri; Operon
PubMed: 30610075
DOI: 10.1128/AEM.02815-18