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1.
World J Microbiol Biotechnol ; 35(9): 133, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31432254

RESUMO

There is a significant increase in the discovery of new antimicrobial compounds in recent past to combat drug resistant pathogens. Members of the genus Bacillus and related genera have been screened extensively due to their ability to produce wide range of antimicrobial compounds. In this study, we have isolated and characterized a new antimicrobial peptide from a marine bacterium identified as Virgibacillus species. The low molecular mass and stability of the antimicrobial substance pointed towards the bacteriocinogenic nature of the compound. The RAST analysis of genome sequence showed presence of a putative bacteriocin biosynthetic cluster containing genes necessary for synthesis of a lanthipeptide. Translated amino acid sequence of mature C-terminal propeptide showed identity with salivaricin A (52.2%) and lacticin A (33.3%). Accordingly, the mass (2417 Da) obtained by MALDI analysis was in agreement with posttranslational modifications of the leader peptide to yield three methyl lanthionine rings and a disulfide bond between two free cysteine residues. The lanthipeptide was named as virgicin, which selectively inhibited the growth of Gram-positive bacteria and biofilm formation by Enterococcus faecalis. Inhibition of biofilm formation by E. faecalis was also observed in in vitro model experiments using hydroxyapatite discs. Thus, virgicin appears to be a promising new bacteriocin to control oral biofilm formation by selective pathogens.


Assuntos
Bacteriocinas/isolamento & purificação , Bacteriocinas/farmacologia , Enterococcus faecalis/efeitos dos fármacos , Enterococcus faecalis/crescimento & desenvolvimento , Peptídeos/isolamento & purificação , Peptídeos/farmacologia , Virgibacillus/metabolismo , Bacteriocinas/química , Bacteriocinas/genética , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Vias Biossintéticas/genética , Genoma Bacteriano , Peso Molecular , Família Multigênica , Peptídeos/química , Peptídeos/genética , Água do Mar/microbiologia , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Virgibacillus/classificação , Virgibacillus/isolamento & purificação
2.
Microbiol Res ; 227: 126303, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421717

RESUMO

The inhibitory action that a Brevibacillus laterosporus strain isolated from the honeybee body causes against the American Foulbrood (AFB) etiological agent Paenibacillus larvae was studied by in-vitro experiments. A protein fraction isolated from B. laterosporus culture supernatant was involved in the observed inhibition of P. larvae vegetative growth and spore germination. As a result of LC-MS/MS proteomic analyses, the bacteriocin laterosporulin was found to be the major component of this fraction, followed by other antimicrobial proteins and substances including lectins, chaperonins, various enzymes and a number of putative uncharacterized proteins. The results obtained in this study highlight the potential of B. laterosporus as a biological control agent for preserving and improving honeybee health.


Assuntos
Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/farmacologia , Abelhas/microbiologia , Brevibacillus/metabolismo , Paenibacillus larvae/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Bacteriocinas/isolamento & purificação , Bacteriocinas/farmacologia , Brevibacillus/isolamento & purificação , Cromatografia Líquida , Testes de Sensibilidade Microbiana , Proteômica , Espectrometria de Massas em Tandem
3.
Phys Chem Chem Phys ; 21(23): 12530-12539, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31147666

RESUMO

The emergence of antibiotic-resistance is a major concern to global human health and identification of novel antibiotics is critical to mitigate the threat. Mutacin 1140 (MU1140) is a promising antimicrobial lanthipeptide and is effective against Gram-positive bacteria. Like nisin, MU1140 targets and sequesters lipid II and interferes with its function, which results in the inhibition of bacterial cell wall synthesis, and leads to bacteria cell lysis. MU1140 contains a structurally similar thioether cage for binding the lipid II pyrophosphate as for nisin. In addition to lipid II binding, nisin is known to form membrane pores. Membrane pore formation and membrane disruption is a common mode of action for many antimicrobial peptides, including gallidermin, a lantibiotic peptide with similar structural features as MU1140. However, whether and how MU1140 and its variants can form permeable membrane pores remains to be demonstrated. In this work, we explored the potential mechanisms of membrane pore formation by performing molecular simulations of the MU1140-lipid II complex in the bacterial membrane. Our results suggest that MU1140-lipid II complexes are able to form water permeating membrane pores. We find that a single chain of MU1140 complexed with lipid II in the transmembrane region can permeate water molecules across the membrane via a single-file water transport mechanism. The ordering of the water molecules in the single-file chain region as well as the diffusion behavior is similar to those observed in other biological water channels. Multiple complexes of MU1140-lipid II in the membrane showed enhanced permeability for the water molecules, as well as a noticeable membrane distortion and lipid relocation, suggesting that a higher concentration of MU1140 assembly in the membrane can cause significant disruption of the bacterial membrane. These investigations provide an atomistic level insight into a novel mode of action for MU1140 that can be exploited to develop optimized peptide variants with improved antimicrobial properties.


Assuntos
Bacteriocinas/farmacologia , Bactérias Gram-Positivas/efeitos dos fármacos , Simulação de Dinâmica Molecular , Peptídeos/farmacologia , Bacteriocinas/química , Membrana Celular/efeitos dos fármacos , Bactérias Gram-Positivas/citologia , Lipídeos/química , Lipídeos/farmacologia , Testes de Sensibilidade Microbiana , Peptídeos/química , Água/química
4.
World J Microbiol Biotechnol ; 35(7): 96, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31218558

RESUMO

The biofilm-forming ability of Listeria spp. is a concern to the food industry and health sectors. The aim of this study was to verify the inhibitory activity of bacteriocins produced by enterococci (Enterococcus faecium 20, 22 and 24 and Enterococcus faecalis 27) on developing biofilm and preformed biofilm of Listeria species. Bacteriocins were partially purified from cell free supernatant (CFS). L. monocytogenes 2032, L. innocua 2050 and L. ivanovii 2056 were selected to analyse the inhibitory effect of bacteriocins on biofilm biomass (crystal violet staining) and biofilm viability (XTT-reduction). The biomass of the developing and preformed biofilms of Listeria species were reduced (p < 0.05) in the presence of all bacteriocins tested. Overall, the reduction in biofilm biomass of developing biofilms was up to 87.4% for bacteriocin produced by E. faecium 22 (CFS22) against L. ivanovii and up to 87.1% for CFS22 against L. monocytogenes. These findings are in accordance with those observed in confocal microscopy analysis. Most of the CFS-containing bacteriocin (CFS22, CFS24, CFS27) were effective at decreasing the viability of biofilm cells from all Listeria species. The highest reduction in viability was observed for L. monocytogenes preformed biofilm cells (up to 98.7%), evidenced by fluorescence microscopy of propidium iodide-labelled cells. Scanning electron microscopy showed that cells of biofilm-treated bacteriocins displayed degenerative changes that may be indicative of cellular leakages. This study suggests that bacteriocins produced by enterococci have prospective applications to prevent biofilm formation and/or to reduce cell viability of formed biofilms of distinct Listeria species.


Assuntos
Bacteriocinas/farmacologia , Biofilmes/efeitos dos fármacos , Enterococcus/metabolismo , Listeria monocytogenes/efeitos dos fármacos , Listeria/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Biomassa , Enterococcus faecalis/metabolismo , Enterococcus faecium/metabolismo , Indústria de Processamento de Alimentos , Viabilidade Microbiana/efeitos dos fármacos
5.
Int J Food Microbiol ; 304: 19-31, 2019 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-31151072

RESUMO

Reducing salt content in foods such as cheeses, while limiting the growth of spoilage microorganisms and foodborne pathogens, is a difficult challenge. One method that may prove useful is use of staphylococcins, which are bacteriocins produced by staphylococci. Therefore, staphylococcin antimicrobial activity against six strains of S. aureus isolated from cheese was tested aiming at their industrial application in biopreservation of Minas fresh (Frescal) cheese with reduced sodium content. Three staphylococcins were selected for these tests: Pep 5, aureocin A53 and lysostaphin. All three staphylococcins proved to be bacteriolytic against all six strains of S. aureus. The antimicrobial activity of the partially purified staphylococcins was subsequently investigated against strains S. aureus Q1 and QJ3 in cheese matrices (6.0 log CFU/g) with different NaCl contents (control, a 25% reduction, and a 50% reduction), kept under refrigeration at 4 °C, for 21 days. Both strains were shown to be of concern for food industry as they carry the SEA, SEB and SEH enterotoxin genes, and are resistant to ß-lactam drugs and moderate biofilm formers when grown in TSB. When used singly, Pep5, aureocin A53 and lysostaphin reduced approximately 95%, 99% and 99.99% of the viable cell counts, respectively, irrespective of the sodium content of the cheese matrix. The combined action of aureocin A53 and Pep5 resulted in an additional and significant reduction (p < 0.05) of ~1.0 log CFU/g when compared with the reduction caused by the use of either one singly. The combined action of lysostaphin and aureocin A53 or lysostaphin and Pep5 resulted in a reduction similar to or slightly smaller (p > 0.05) than that observed when lysostaphin was employed singly. Lysostaphin also proved to reduce the number of the staphylococcal viable cells to a level (~ 2.0 log CFU/g) at which enterotoxin production should not reach a sufficient quantity to cause food poisoning. Therefore, lysostaphin may have a practical application in the food industry to control staphylococcal contamination of Minas fresh cheese with a sodium content reduced up to 50%, providing consumers with more safe options to reduce their intake of sodium.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Queijo/microbiologia , Doenças Transmitidas por Alimentos/prevenção & controle , Lisostafina/farmacologia , Peptídeos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Enterotoxinas/análise , Doenças Transmitidas por Alimentos/microbiologia , Cloreto de Sódio/análise , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/metabolismo
6.
J Microbiol Biotechnol ; 29(7): 1033-1042, 2019 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-31216789

RESUMO

Bacillus velezensis BS2 was isolated from meongge (common sea squirt) jeotgal, a Korean fermented seafood, and produces a bacteriocin, BacBS2, which strongly inhibits Listeria monocytogenes and Bacillus cereus. BacBS2 was partially purified by Q-Sepharose column chromatography after ammonium sulfate precipitation of the culture supernatant, then further purified by Sephadex G-50 column chromatography. Partially purified BacBS2 was estimated to be 6.5 kDa in size by Tricine-SDS PAGE and activity detection by gel-overlay. Enzyme treatment and FT-IR spectrum of partially purified BacBS2 confirmed its proteinaceous nature. BacBS2 was fully stable at pH 4-9, and half of activity was retained at pH 1-3. Full activity was retained after exposure to 80°C for 15 min, but half of the activity was retained upon exposure to 90°C for 15 min or 100°C for 10 min. BacBS2 inhibited L. monocytogenes by bactericidal mode of action. B. velezensis BS2 and its BacBS2 seem useful as biopreservatives for fermented foods such as jeotgal.


Assuntos
Antibacterianos/metabolismo , Bacillus/metabolismo , Bacteriocinas/isolamento & purificação , Bacteriocinas/metabolismo , Alimentos Fermentados/microbiologia , Conservantes de Alimentos/metabolismo , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Antibiose , Bacillus/crescimento & desenvolvimento , Bacillus/fisiologia , Bacillus cereus/efeitos dos fármacos , Bacteriocinas/química , Bacteriocinas/farmacologia , Meios de Cultura , Conservantes de Alimentos/química , Conservantes de Alimentos/isolamento & purificação , Conservantes de Alimentos/farmacologia , Temperatura Alta , Concentração de Íons de Hidrogênio , Listeria monocytogenes/efeitos dos fármacos , Peso Molecular , Estabilidade Proteica
7.
MBio ; 10(2)2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-31040244

RESUMO

Microcin C (McC) is a peptide adenylate antibiotic produced by Escherichia coli cells bearing a plasmid-borne mcc gene cluster. Most MccA precursors, encoded by validated mcc operons from diverse bacteria, are 7 amino acids long, but the significance of this precursor length conservation has remained unclear. Here, we created derivatives of E. coli mcc operons encoding longer precursors and studied their synthesis and bioactivities. We found that increasing the precursor length to 11 amino acids and beyond strongly decreased antibiotic production. We found this decrease to depend on several parameters. First, reiterative synthesis of the MccA peptide by the ribosome was decreased at longer mccA open reading frames, leading to less efficient competition with other messenger RNAs. Second, the presence of a formyl group at the N-terminal methionine of the heptameric peptide had a strong stimulatory effect on adenylation by the MccB enzyme. No such formyl group stimulation was observed for longer peptides. Finally, the presence of the N-terminal formyl on the heptapeptide adenylate stimulated bioactivity, most likely at the uptake stage. Together, these factors should contribute to optimal activity of McC-like compounds as 7-amino-acid peptide moieties and suggest convergent evolution of several steps of the antibiotic biosynthesis pathway and their adjustment to sensitive cell uptake machinery to create a potent drug.IMPORTANCE Escherichia coli microcin C (McC) is a representative member of peptide-nucleotide antibiotics produced by diverse microorganisms. The vast majority of biosynthetic gene clusters responsible for McC-like compound production encode 7-amino-acid-long precursor peptides, which are C-terminally modified by dedicated biosynthetic enzymes with a nucleotide moiety to produce a bioactive compound. In contrast, the sequences of McC-like compound precursor peptides are not conserved. Here, we studied the consequences of E. coli McC precursor peptide length increase on antibiotic production and activity. We show that increasing the precursor peptide length strongly decreases McC production by affecting multiple biosynthetic steps, suggesting that the McC biosynthesis system has evolved under significant functional constraints to maintain the precursor peptide length.


Assuntos
Antibacterianos/metabolismo , Antibacterianos/farmacologia , Bacteriocinas/metabolismo , Bacteriocinas/farmacologia , Escherichia coli/metabolismo , Biossíntese de Proteínas , Ribossomos/metabolismo , Bacteriocinas/genética , Análise Mutacional de DNA , Escherichia coli/genética , N-Formilmetionina/metabolismo , Fases de Leitura Aberta , Plasmídeos
8.
Dokl Biochem Biophys ; 484(1): 42-44, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31012010

RESUMO

Avicin A is a bacteriocin from the gram-positive bacterium Enterococcus avium. It exhibits a high microbicidal activity against bacteria of the genus Listeria, a causative agent of the severe human infection listeriosis. We developed a biotechnological method for obtaining avicin A and characterized its structure and biological activity. We also proposed a possible mechanism of the antimicrobial action of avicin A.


Assuntos
Antibacterianos , Bacteriocinas , Enterococcus/química , Listeria/crescimento & desenvolvimento , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Bacteriocinas/química , Bacteriocinas/isolamento & purificação , Bacteriocinas/farmacologia
9.
J Appl Microbiol ; 127(1): 78-87, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31021024

RESUMO

AIMS: To determine the characteristics of the novel phage tail-like bacteriocin (PTLB) produced by Stenotrophomonas maltophilia S16. METHODS AND RESULTS: A screen to identify novel bacteriocins from a panel of 86 S. maltophilia strains was performed. We found that 62 tested S. maltophilia strains were sensitive to a PTLB, designated maltocin S16. In addition, 8 of 14 tested Escherichia coli strains were also susceptible to maltocin S16. Minimum inhibitory concentration determination confirmed that maltocin S16 had rather high bactericidal activity against both S. maltophilia and E. coli. Maltocin S16 was resistant to trypsin and proteinase K. Furthermore, lipopolysaccharide was found to be involved in the adsorption of maltocin S16. The gene cluster of maltocin S16 was consisted of 23 putative open reading frames. Phylogenetic analysis indicated that maltocin S16 represents a new class of PTLB in S. maltophilia. CONCLUSION: Maltocin S16 was a novel PTLB with broad-spectrum and high bactericidal activity against S. maltophilia and E. coli. SIGNIFICANCE AND IMPACT OF THE STUDY: Stenotrophomonas maltophilia is a multidrug-resistant opportunistic pathogen with increasing contributions to infectious disease morbidity and mortality. Maltocin S16 could be a promising alternative for antibiotics against S. maltophilia and E. coli infections.


Assuntos
Bacteriocinas/farmacologia , Escherichia coli/efeitos dos fármacos , Stenotrophomonas maltophilia/efeitos dos fármacos , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Bacteriocinas/genética , Bacteriocinas/isolamento & purificação , Humanos , Testes de Sensibilidade Microbiana , Filogenia
10.
Food Microbiol ; 82: 30-35, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31027787

RESUMO

Mushroom growth substrates from different commercial producers of mushrooms (Agaricus bisporus) were screened for the presence of bacteria with potential for use as biocontrol agents for controlling Listeria monocytogenes in the mushroom production environment. Eight anti-listerial strains were isolated from different sources and all were identified using 16s rRNA gene sequencing as Lactococcus lactis subsp. lactis. Whole-genome sequencing of the Lc. lactis isolates indicated that strains from different sites and substrate types were highly similar. Colony MALDI-TOF mass spectrometry found that these strains were Nisin Z producers but inhibitory activity was highly influenced by the incubation conditions and was strain dependant. The biofilm forming ability of these strains was tested using a crystal violet assay and all were found to be strong biofilm formers. Growth of Lc. lactis subsp. lactis using mixed-biofilm conditions with L. monocytogenes on stainless steel resulted in a 4-log reduction of L. monocytogenes cell numbers. Additional sampling of mushroom producers showed that these anti-listerial Lc. lactis strains are commonly present in the mushroom production environment. Lc. lactis has a generally regarded as safe (GRAS) status and therefore has potential for use as an environmentally benign solution to control L. monocytogenes in order to prevent product contamination and to enhance consumer confidence in the mushroom industry.


Assuntos
Agaricales , Antibiose , Bacteriocinas/farmacologia , Agentes de Controle Biológico , Microbiologia de Alimentos , Lactococcus lactis/fisiologia , Listeria monocytogenes/patogenicidade , Biofilmes , Contaminação de Alimentos/prevenção & controle , Sequenciamento de Nucleotídeos em Larga Escala , RNA Ribossômico 16S/genética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Aço Inoxidável
11.
Int J Antimicrob Agents ; 53(6): 838-843, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30928682

RESUMO

The alarming burden of antibiotic resistance in nosocomial pathogens warrants the discovery and development of new and effective antimicrobial compounds. Small cationic antimicrobial peptides seem to be a promising therapeutic alternative to fight multi-drug resistance. This study investigated the in-vitro potential of a previously reported lantibiotic, paenibacillin, from the clinical perspective. An antimicrobial peptide, M152-P4, was isolated, purified and characterized from a mud isolate, and its susceptibility was determined in clinical isolates of Staphylococcus aureus and Enterococcus spp. Time-kill kinetics, resistance, probable mode of action, haemolytic activity and mammalian cytotoxicity were investigated. M152-P4 was identified as paenibacillin based on mass spectroscopy data, amino acid analysis and biosynthetic gene cluster analysis. It had potent antibacterial activity against the Gram-positive pathogens tested, with minimum inhibitory concentrations from 0.1 to 1.56 µM. It appeared very challenging for S. aureus to develop resistance to this compound. Also, paenibacillin penetrated the outer layer of bacteria, and depolarized the membrane completely by creating pores in the plasma membrane with better potential than nisin. Paenibacillin showed no haemolysis up to 60 µM, and the half maximal inhibitory concentration on mammalian cell lines was >100 µM. These results highlight the excellent antibacterial properties of paenibacillin in clinically relevant pathogens. It is stable in the presence of serum, and non-haemolytic and non-cytotoxic even above the therapeutic concentration. Further research efforts regarding toxicity and in-vivo efficacy are necessary to develop paenibacillin as a next-generation therapeutic drug to overcome multi-drug resistance in Gram-positive pathogens.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bacteriocinas/farmacologia , Enterococcus/efeitos dos fármacos , Paenibacillus/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/toxicidade , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/toxicidade , Bacteriocinas/química , Bacteriocinas/isolamento & purificação , Bacteriocinas/toxicidade , Vias Biossintéticas/genética , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Farmacorresistência Bacteriana , Humanos , Espectrometria de Massas , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Família Multigênica , Paenibacillus/classificação , Paenibacillus/isolamento & purificação , Análise de Sequência de Proteína , Esgotos/microbiologia
12.
Artigo em Inglês | MEDLINE | ID: mdl-30897806

RESUMO

Antimicrobial compounds from traditional fermented foods have shown activity against a wide range of pathogen and spoilage microorganisms for several years. In this study, a Lactic acid bacteria (LAB), isolated from Vietnamese traditional fermented yogurt (Lactobacillus plantarum SC01), was encapsulated in alginate-gelatin (ALG-GEL) and the effect of incubation temperature, medium pH and surfactants were assessed. The aims of this research were to evaluate antimicrobial activity of bacteriocin produced by L. plantarum SC01. Another aim the research was to study the quality of pork meat treated with its Bacteriocin in 2 h as a bio-preservative at different storage times (0 h, 12 h, 24 h and 48 h) in room temperature, compared to control (treated with salt 40.0%). The antimicrobial activity of L. plantarum SC01 was identified through the inhibition rate of five indicator organisms, including Escherichia coli, Salmonella sp., Staphylococcus aureus, Listeria monocytogenes, and Bacillus subtilis by co-culture method. The results showed that L. plantarum SC01 microencapsulated in ALG-GEL (2.5% alginate and 6.0% gelatin, w/v) and 3.0% bacteria supplied into modified MRS medium (MRSOPTSC01) produced highly active compound inhibited the growth of indicator organisms at a density of 104⁻108 CFU/mL. Antibacterial compounds were highly active in a treatment at 80 °C; not to be affected by pH; affected by surfactant as Ethylenediaminetetraacetic acid (EDTA), Sodium dodecyl sulfate (SDS), and Tween. Moreover, LAB obtained from this study show the potent Bacteriocin in its usage as a preservative in food.


Assuntos
Alginatos/química , Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Conservação de Alimentos/métodos , Lactobacillus plantarum , Carne Vermelha/microbiologia , Animais , Cápsulas , Gelatina/química , Concentração de Íons de Hidrogênio , Staphylococcus aureus/efeitos dos fármacos , Tensoativos/farmacologia , Suínos , Temperatura Ambiente
13.
Nat Commun ; 10(1): 1115, 2019 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-30846700

RESUMO

The genome of the thermophilic bacterium, Aeribacillus pallidus 8, encodes the bacteriocin pallidocin. It belongs to the small class of glycocins and is posttranslationally modified, containing an S-linked glucose on a specific Cys residue. In this study, the pallidocin biosynthetic machinery is cloned and expressed in Escherichia coli to achieve its full biosynthesis and modification. It targets other thermophilic bacteria with potent activity, demonstrated by a low minimum inhibitory concentration (MIC) value. Moreover, the characterized biosynthetic machinery is employed to produce two other glycopeptides Hyp1 and Hyp2. Pallidocin and Hyp1 exhibit antibacterial activity against closely related thermophilic bacteria and some Bacillus sp. strains. Thus, heterologous expression of a glycocin biosynthetic gene cluster including an S-glycosyltransferase provides a good tool for production of hypothetical glycocins encoded by various bacterial genomes and allows rapid in vivo screening.


Assuntos
Bacillaceae/metabolismo , Bacteriocinas/biossíntese , Sequência de Aminoácidos , Antibacterianos/biossíntese , Antibacterianos/química , Antibacterianos/farmacologia , Bacillaceae/genética , Bacteriocinas/genética , Bacteriocinas/farmacologia , Clonagem Molecular , Dissulfetos/química , Escherichia coli/genética , Escherichia coli/metabolismo , Genes Bacterianos , Glicopeptídeos/biossíntese , Glicopeptídeos/genética , Glicopeptídeos/farmacologia , Testes de Sensibilidade Microbiana , Família Multigênica , Estrutura Terciária de Proteína , Homologia de Sequência de Aminoácidos
14.
J Sci Food Agric ; 99(10): 4731-4738, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30924936

RESUMO

BACKGROUND: Sakacin-A due to its specific antimicrobial activity may represent a good candidate to develop active packaging solutions for food items supporting Listeria growth. In the present study a protein extract containing the bacteriocin sakacin-A, produced by Lactobacillus sakei Lb 706 in a low-cost culture medium containing deproteinized cheese whey, was adsorbed onto cellulose nanofibers (CNFs) to obtain an active material to be used as a mat (or a separator) in direct contact with foods. RESULTS: The applied fermentation conditions allowed 4.51 g L-1 of freeze-dried protein extract to be obtained, characterized by an antimicrobial activity of near 16 700 AU g-1 , that was used for the preparation of the active material by casting. The active material was then characterized by infrared spectra and thermogravimetric analyses. Antimicrobial trials were carried out in vitro using Listeria innocua as indicator strain; results were also confirmed in vivo, employing smoked salmon fillets intentionally inoculated with Listeria innocua: its final population was reduced to about 2.5-3 Log cycles after 28 days of storage at 6 °C in presence of sakacin-A, compared with negative control mats produced without the bacteriocin extract. CONCLUSION: This study demonstrates the possibility of producing an antimicrobial active material containing sakacin-A absorbed onto CNFs to decrease Listeria population in smoked salmon, a ready-to eat-food product. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.


Assuntos
Antibacterianos/química , Bacteriocinas/química , Produtos Pesqueiros/análise , Conservação de Alimentos/métodos , Conservantes de Alimentos/química , Nanofibras/química , Animais , Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Celulose/química , Fast Foods/análise , Fast Foods/microbiologia , Produtos Pesqueiros/microbiologia , Conservação de Alimentos/instrumentação , Conservantes de Alimentos/farmacologia , Listeria/crescimento & desenvolvimento , Salmão/microbiologia
15.
Carbohydr Polym ; 209: 172-180, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30732796

RESUMO

Enterococcus faecium (E. faecium) isolated from Vigna mungo (Black gram) produced bacteriocin that inhibits both Gram positive and Gram negative bacteria and better heat stability (100 °C for 30 min). The bacteriocin was sensitive to protease treatment and most active in acidic pH. Bacteriocin produced by Pediococcus acidilactici was used for comparison. To enhance stability for diversified applications, the bacteriocin was immobilized by physical adsorption onto cellulose nanocrystals (CNC) extracted from cotton linters. The bacteriocin immobilization yield was 64.91% for P. acidilactici and 53.63% for E. faecium. The bacteriocin immobilized CNC was characterized by DLS particle sizing, FTIR and AFM to evaluate size distribution, chemical nature and surface morphology. The bacteriocins immobilized on CNC showed 50% increase in stability in terms of antibacterial activity. The enzymatic synthesis of CNC in combination with physical adsorption immobilization method for bacteriocin makes it an efficient system of producing antibacterial nanofillers for food packaging and bio-composites applications.


Assuntos
Antibacterianos/química , Bacteriocinas/química , Celulose/química , Enterococcus faecium/química , Proteínas Imobilizadas/química , Nanopartículas/química , Antibacterianos/isolamento & purificação , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Bacteriocinas/isolamento & purificação , Bacteriocinas/metabolismo , Bacteriocinas/farmacologia , Concentração de Íons de Hidrogênio , Proteínas Imobilizadas/isolamento & purificação , Proteínas Imobilizadas/metabolismo , Proteínas Imobilizadas/farmacologia , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Estabilidade Proteica , Proteólise , Cloreto de Sódio/química , Temperatura Ambiente
16.
J Dairy Sci ; 102(4): 2928-2940, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30799112

RESUMO

Bacteriocins have attracted great attention as potential alternatives to antibiotics and chemical food additives. In the present study, 243 Staphylococcus isolates from milk samples (n = 110) of goat and sheep herds located in Fars province, Iran, were screened for antimicrobial substance production. Twenty-eight isolates showed an antagonistic activity against the indicator strain Micrococcus luteus ATCC 4698. The susceptibility of all antimicrobial substances to proteolytic enzymes allowed us to consider them as bacteriocin-like inhibitory substances (BLIS). The term BLIS is applied to uncharacterized proteinaceous antimicrobials produced by gram-positive bacteria. Based on molecular identification methods, the isolates belonged to the species Staphylococcus chromogenes, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus pseudintermedius, Staphylococcus aureus, and Staphylococcus agnetis. Pulsed-field gel electrophoresis revealed a high level of genotype diversity among the Staph. chromogenes isolates. All of the isolates harbored nukA or bsaA2 genes, suggesting that their BLIS were related to nukacin or Bsa. The antimicrobial compounds from test strains were not effective against gram-negative pathogens, including Salmonella enterica serovar Typhimurium, Escherichia coli O157:H7, and Klebsiella pneumonia as well as the indicator mold Aspergillus fumigatus. All the gram-positive targets, including Bacillus cereus, Listeria monocytogenes, Enterococcus faecalis Ef37 (a tyramine-producer strain), Lactobacillus saerimneri 30a (a histamine-producer strain), and methicillin-resistant Staph. epidermidis, were inhibited by the Staph. chromogenes isolates. Staphylococcus haemolyticus 4S12 was able to inhibit the majority of gram-positive bacteria. Listeria monocytogenes strains were the only indicators sensitive to the antimicrobial agents produced by Staph. agnetis 4S97B. The other Staphylococcus strains were ineffective on all the organisms tested. Based on their inhibitory capacities, the BLIS produced by the Staph. chromogenes isolates seem to be interesting candidates for developing novel antimicrobial agents.


Assuntos
Bacteriocinas/farmacologia , Cabras , Leite/microbiologia , Ovinos , Staphylococcus/metabolismo , Animais , Antibacterianos , Anti-Infecciosos , Bacillus cereus/efeitos dos fármacos , Bacteriocinas/metabolismo , Irã (Geográfico) , Lactobacillus/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos , Staphylococcus/isolamento & purificação
17.
Biochimie ; 160: 141-147, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30790617

RESUMO

Microcin J25 (MccJ25), an antimicrobial peptide, targets the respiratory chain but the exact mechanism by which it does so remains unclear. Here, we reveal that MccJ25 is able to inhibit the enzymatic activity of the isolated cytochrome bd-I from E. coli and induces at the same time production of reactive oxygen species. MccJ25 behaves as a dose-dependent weak inhibitor. Intriguingly, MccJ25 is capable of producing a change in the oxidation state of cytochrome bd-I causing its partial reduction in the presence of cyanide. These effects are specific for cytochrome bd-I, since the peptide is not able to act on purified cytochrome bo3.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Citocromos/metabolismo , Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/enzimologia , Oxirredutases/antagonistas & inibidores , Oxirredutases/metabolismo , Cianetos/farmacologia , Citocromos/antagonistas & inibidores , Citocromos/genética , Complexo de Proteínas da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Complexo de Proteínas da Cadeia de Transporte de Elétrons/genética , Escherichia coli/efeitos dos fármacos , Proteínas de Escherichia coli/antagonistas & inibidores , Proteínas de Escherichia coli/genética , Oxirredução , Oxirredutases/genética , Espécies Reativas de Oxigênio/metabolismo
18.
Biotechnol Lett ; 41(4-5): 453-469, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30739282

RESUMO

The encapsulation of bacteriocins from lactic acid bacteria has involved several methods to protect them from unfavourable environmental conditions and incompatibilities. This review encompasses different methods for the encapsulation of bacteriocins and their applications in both food and pharmaceutical fields. Based on the bibliometric analysis of publications from well-reputed journals including different available patents during the period from 1996 to 2017, 135 articles and 60 patents were collected. Continent-wise contributions to the bacteriocins encapsulation research were carried out by America (52%), Asia (29%) and Europe (19%); with the United States of America, Brazil, Thailand and Italy the countries with major contributions. Till date, different methods proposed for encapsulation have been (i) Film coatings (50%), (ii) Liposomes (23%), (iii) Nanofibers (22%) and (iv) Nanoparticles (4%). Bacteriocins encapsulation methods frequently carried out in food protection (70%); while in the pharmaceutical field, 30% of the research was conducted on multi drug resistant therapy.


Assuntos
Antibacterianos/farmacologia , Infecções Bacterianas/tratamento farmacológico , Bacteriocinas/farmacologia , Composição de Medicamentos/métodos , Conservantes de Alimentos/farmacologia , Tecnologia Farmacêutica/métodos , Tecnologia Farmacêutica/tendências
19.
Benef Microbes ; 10(3): 329-349, 2019 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-30773929

RESUMO

Probiotics play an important role in maintaining a healthy and stable intestinal microbiota, primarily by preventing infection. Probiotic lactic acid bacteria (LAB) are known to be inhibitory to many bacterial enteric pathogens, including antibiotic-resistant strains. Whilst the positive role that probiotics have on human physiology, specifically in the treatment or prevention of specific infectious diseases of the gastro-intestinal tract (GIT) is known, the precise mechanistic basis of these effects remains a major research goal. In this study, molecular evidence to underpin the protective and anti-listerial effect of Lactobacillus plantarum 423 and Enterococcus mundtii ST4SA against orally administered Listeria monocytogenes EGDe in the GIT of mice is provided. Bacteriocins plantaricin 423 and mundticin ST4SA, produced by L. plantarum 423 and E. mundtii ST4SA, respectively, inhibited the growth of L. monocytogenes in vitro and in vivo. Bacteriocin-negative mutants of L. plantarum 423 and E. mundtii ST4SA failed to exclude L. monocytogenes EGDe from the gastrointestinal tract (GIT) of mice. Furthermore, L. plantarum 423 and E. mundtii ST4SA failed to inhibit recombinant strains of L. monocytogenes EGDe in vivo that expressed the immunity proteins of the two bacteriocins. These results confirmed that bacteriocins plantaricin 423 and mundticin ST4SA acted as anti-infective mediators in vivo. Compared to wild type strains, mutants of L. plantarum 423 and E. mundtii ST4SA, in which the adhesion genes were knocked out, were less effective in the exclusion of L. monocytogenes EGDe from the GIT of mice. This work demonstrates the importance of bacteriocin and adhesion genes as probiotic anti-infective mechanisms.


Assuntos
Antibacterianos/metabolismo , Aderência Bacteriana/fisiologia , Bacteriocinas/metabolismo , Enterococcus/química , Lactobacillus plantarum/química , Listeria monocytogenes/crescimento & desenvolvimento , Animais , Antibacterianos/farmacologia , Antibiose , Aderência Bacteriana/genética , Bacteriocinas/genética , Bacteriocinas/farmacologia , Enterococcus/genética , Feminino , Trato Gastrointestinal/microbiologia , Lactobacillus plantarum/genética , Listeria monocytogenes/efeitos dos fármacos , Camundongos Endogâmicos BALB C , Mutação , Probióticos
20.
Benef Microbes ; 10(3): 315-328, 2019 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-30773930

RESUMO

Bacteriocins are bacterially-produced antimicrobial peptides that have killing activity principally against other relatively closely-related bacteria. Some bacteriocins of the lactic acid bacteria (LAB) have for many years been extensively applied in food biopreservation. However, especially during the last decade, a number of reports have appeared about unanticipated extensions to the generally rather narrow anti-bacterial activity spectrum of some of the LAB bacteriocins and novel applications have been proposed for bacteriocins ranging from controlling the growth of an increasingly-heterogeneous variety of pathogens, including Gram-negative multidrug resistant bacteria, viruses, yeasts, and in particular, difficult to control Mycobacterium spp., to their potential application as anticancer agents. How best can we assess this now rapidly-accumulating stream of reports on potential future applications of bacteriocins? Where is the line between realistic, science-based proposals and highly-speculative fiction and what are the 'critical points' that might help us to draw this line? In this review, we have attempted to analyse a selection of the presently-available data concerning relatively 'unorthodox' (i.e. beyond food preservation) applications of bacteriocins, and, by utilising our set of 'critical points', we endeavour to identify essential or/and missing information that appear crucial for success of the proposed applications.


Assuntos
Bacteriocinas/farmacologia , Lactobacillales/química , Antibacterianos , Antifúngicos , Antineoplásicos , Antivirais , Bacteriocinas/biossíntese , Conservantes de Alimentos , Mycobacterium/efeitos dos fármacos , Mycobacterium/crescimento & desenvolvimento , Nisina/farmacologia , Percepção de Quorum
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