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1.
PLoS One ; 15(7): e0235873, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32687505

RESUMO

This study evaluates whole-genome sequence of Lactobacillus reuteri PNW1 and identifies its safety genes that may qualify it as a putative probiotic. It further extracted the bacteriocin produced by the strain and tested its effectiveness against pathogenic STEC E. coli O177. The genomic DNA was sequenced on illuminal Miseq instrument and the sequenced data was assessed for quality reads before assembled with SPAdes. The draft assembly was annotated with Prokaryotic Genome Annotation Pipeline (PGAP) and Rapid Annotations using Subsystems Technology (RAST). Further downstream analyses were carried out using appropriate bioinformatic tools. Production of biogenic amines was biochemically confirmed through HPLC analysis. The assembled genome was 2,430,215 bp long in 420 contigs with 39% G+C content. Among all known genes, putatively responsible for the production of toxic biochemicals, only arginine deiminase (EC3.5.3.6) was spotted. Coding sequences (CDS) putative for D-lactate dehydrogenase (EC1.1.1.28), L-lactate dehydrogenase (EC1.1.1.27) and bacteriocin helveticin J were found within the genome together with plethora of other probiotic important genes. The strain harbours only resistant genes putative for Lincosamide (lnuC) and Tetracycline resistant genes (tetW). There was no hit found for virulence factors and probability of the strain being a human pathogen was zero. Two intact prophage regions were detected within the genome of L. reuteri PNW1 and nine CDS were identified for insertion sequence by OASIS which are belong to seven different families. Five putative CDS were identified for the CRISPR, each associated with Cas genes. Maximum zone of inhibition exhibited by the bacteriocin produced L. reuteri PNW1 is 20.0±1.00 mm (crude) and 23.3±1.15 mm (at 0.25 mg/ml) after being partially purified. With the strain predicted as non-human pathogen, coupled with many other identified desired features, L. reuteri PNW1 stands a chance of making good and safe candidates for probiotic, though further in-vivo investigations are still necessary.


Assuntos
Genoma Bacteriano , Lactobacillus reuteri/genética , Probióticos/efeitos adversos , Proteínas de Bactérias/genética , Bacteriocinas/genética , Bacteriocinas/metabolismo , Bacteriocinas/farmacologia , Escherichia coli/efeitos dos fármacos , Hidrolases/genética , L-Lactato Desidrogenase/genética , Lactobacillus reuteri/patogenicidade , Anotação de Sequência Molecular , Fatores de Virulência/genética
2.
World J Microbiol Biotechnol ; 36(5): 72, 2020 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-32363424

RESUMO

The bacteriocinogenic lactic acid bacterium Pediococcus pentosaceus LJR1 isolated from rumen liquor of goat had strong anti-bacterial activity toward Listeria monocytogenes in vitro. This antibacterial activity was lost on treatment with protease indicating that the bacteriocin is proteinaceous in nature. The bacteriocin LJR1 produced by P. pentosaceus was purified following a three step procedure consisting of ammonium sulphate precipitation, gel filtration chromatography and reverse phase-high performance liquid chromatography. The molecular weight of purified bacteriocin was determined to be 4.6 kDa using Tricine SDS-PAGE. Further, we found that the proteinaceous bacteriocin was stable at 100 °C as well as 121 °C for 30 min and 15 min respectively and also at different pH ranging from 4 to 10 when stored for 15 min at 37 °C. Its minimum inhibitory concentration for S. typhi MTCC134 and L. monocytogenes MTCC 1143 was 7.81 µg/ml and 15.63 µg/ml respectively. Scanning electron microscopy analysis of the surface of S. typhi treated with the bacteriocin showed the presence of craters; while in the case of treated L. monocytogenes blebs were observed. The addition of the bacteriocin to shrimp (white leg shrimp) has led to reduction of about 1 log units of L. monocytogenes on day 1 and maintained for 7 days on storage at 4 °C. It is clear that the purified bacteriocin has good potential as a bio preservative for application in food industry.


Assuntos
Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Bacteriocinas/isolamento & purificação , Bacteriocinas/farmacologia , Conservação de Alimentos/métodos , Pediococcus pentosaceus/metabolismo , Penaeidae/microbiologia , Animais , Antibacterianos/química , Bacteriocinas/química , Bacteriocinas/genética , Microbiologia de Alimentos , Listeria monocytogenes/citologia , Listeria monocytogenes/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Peso Molecular , Pediocinas/genética , Pediococcus pentosaceus/genética , Salmonella typhi/citologia , Salmonella typhi/efeitos dos fármacos , Alimentos Marinhos/microbiologia
3.
Life Sci ; 254: 117754, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32389833

RESUMO

The most prevalent gastrointestinal (GI) cancers include colorectal cancer, stomach cancer, and liver cancer, known as the most common causes of cancer-related death in both men and women populations in the world. Traditional therapeutic approaches, including surgery, radiotherapy, and chemotherapy have failed in the effective treatment of cancer. Therefore, there is an urgent need for finding new effective anticancer agents. The available evidence and also the promising results of using bacteria as the anticancer agents on numerous cancer cell lines have attracted the attention of scientists for the therapeutic role of bacteria in the field of cancer therapy. Moreover, several studies on the bacteriotherapy agents have used genetic engineering to overcome the challenges and enhance the efficacy with the least drawbacks. Numerous bacterial species that can specifically target and internalize into the tumor cells are used live, attenuated, or genetically as compared to selectively consider the hypoxic condition of tumor, which results in the tumor suppression. The present study is a comprehensive review of the current literature on the use of bacteria and their substances such as bacteriocins and toxins in the treatment of different types of gastrointestinal cancers.


Assuntos
Antineoplásicos/uso terapêutico , Bactérias/metabolismo , Neoplasias Gastrointestinais/terapia , Bacteriocinas/farmacologia , Neoplasias Colorretais/tratamento farmacológico , Microbioma Gastrointestinal/efeitos dos fármacos , Engenharia Genética , Terapia Genética , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Resultado do Tratamento
4.
J Food Sci ; 85(5): 1523-1535, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32282078

RESUMO

Bacteriocins are defined as ribosomally synthesized antibacterial peptides/proteins that either kill or inhibit the growth of other bacteria. In the present study, the physicochemical properties, mode of action, and potential use in food preservation of a novel bacteriocin BM1122 from Lactobacillus crustorum MN047 were studied. It exhibited a broad inhibitory spectrum against selected Gram-positive and Gram-negative bacteria. Kinetic curves revealed efficient time-dependent bactericidal activity. Moreover, BM1122 possessed low hemolytic activity and good thermal stability between 60 and 120 °C. It was resistant to a wide range of pH (2 to 11) and proteinases. The scanning and transmission electron microscopy showed that BM1122 led to plasmolysis of Staphylococcus aureus and pore formation in Escherichia coli. Flow cytometric analysis demonstrated that BM1122 destroyed cell membrane integrity. Additionally, BM1122 could also inhibit biofilm formation and disturb the normal cell cycles of S. aureus and E. coli. Finally, BM1122 may enhance the inhibition of S. aureus and E. coli on beef meat stored at 4 °C for a duration of 10 days. These findings indicated that BM1122 had the potential for use as a natural preservative in the food industry. PRACTICAL APPLICATION: Fresh raw meats are highly perishable products. Bacteriocin BM1122 with a broad antibacterial spectrum can inhibit the growth of microorganisms in beef meat during refrigerated storage.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Lactobacillus/química , Animais , Antibacterianos/química , Antibacterianos/metabolismo , Bacteriocinas/química , Bacteriocinas/metabolismo , Bovinos , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Conservação de Alimentos , Lactobacillus/metabolismo , Carne Vermelha/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento
5.
PLoS One ; 15(4): e0231975, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32324803

RESUMO

Plantaricin BM-1 is a class IIa bacteriocin with a strong bactericidal effect on gram-positive bacteria. Although plantaricin BM-1 also inhibits the growth of some gram-negative bacteria, including Escherichia coli, the mechanism is not clear. In this study, we used tandem mass tag-based quantitative proteomics analysis to examine the inhibitory mechanism of plantaricin BM-1 against E. coli K12, and evaluated the morphological effects by electron microscopy. The results demonstrated that plantaricin BM-1 inhibits the growth of E. coli K12 by bacteriostatic action, mainly acting on the surface of the cell wall, leading to its collapse. Proteomic analysis identified 976 differentially expressed proteins (>1.2-fold change, p < 0.05) under treatment with plantaricin BM-1, including 490 up-regulated proteins and 486 down-regulated proteins. These proteins were mainly involved in peptidoglycan synthesis and energy metabolism pathways, including amino acid, glyoxylate and dicarboxylate, ABC transporter, and quorum-sensing pathways. Specifically, plantaricin BM-1 treatment significantly improved peptidoglycan synthesis and enhanced the tricarboxylic acid cycle in E. coli K12, and altered the expression of cell membrane proteins. These results provide new insight into the inhibition mechanism of class IIa bacteriocins on gram-negative bacteria, which can lay the foundation for its broader use as an alternative to conventional antibiotics.


Assuntos
Bacteriocinas/farmacologia , Escherichia coli K12/efeitos dos fármacos , Escherichia coli K12/metabolismo , Peptidoglicano/biossíntese , Proteômica , Escherichia coli K12/crescimento & desenvolvimento , Proteínas de Escherichia coli/metabolismo , Proteínas de Membrana/metabolismo
6.
J Food Sci ; 85(4): 1203-1212, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32118300

RESUMO

Listeria monocytogenes is often responsible for postprocessing contamination of ready-to-eat (RTE) products including cooked ham. As an emerging technology, atmospheric cold plasma (ACP) has the potential to inactivate L. monocytogenes in packaged RTE meats. The objectives of this study were to evaluate the effect of treatment time, modified atmosphere gas compositions (MAP), ham formulation, and post-treatment storage (1 and 7 days at 4 °C) on the reduction of a five-strain cocktail of L. monocytogenes and quality changes in ham subjected to in-package ACP treatment. Initial average cells population on ham surfaces were 8 log CFU/cm2 . The ACP treatment time and gas composition significantly (P < 0.05) influenced the inactivation of L. monocytogenes, irrespective of ham formulations. When MAP1 (20% O2 + 40% CO2 + 40% N2 ) was used, there was a significantly higher log reduction (>2 log reduction) in L. monocytogenes on ham in comparison to MAP2 (50% CO2 + 50% N2 ) and MAP3 (100% CO2 ), irrespective of ham formulation. Addition of preservatives (that is, 0.1% sodium diacetate and 1.4% sodium lactate) or bacteriocins (that is, 0.05% of a partially purified culture ferment from Carnobacterium maltaromaticum UAL 307) did not significantly reduce cell counts of L. monocytogenes after ACP treatment. Regardless of type of ham, storage of 24 hr after ACP treatment significantly reduced cells counts of L. monocytogenes to approximately 4 log CFU/cm2 . Following 7 days of storage after ACP treatment, L. monocytogenes counts were below the detection limit (>6 log reduction) when samples were stored in MAP1. However, there were significant changes in lipid oxidation and color after post-treatment storage. In conclusion, the antimicrobial efficacy of ACP is strongly influenced by gas composition inside the package and post-treatment storage. PRACTICAL APPLICATION: Surface contamination of RTE ham with L. monocytogenes may occur during processing steps such as slicing and packaging. In-package ACP is an emerging nonthermal technology, which can be used as a postpackaging decontamination step in industrial settings. This study demonstrated the influence of in-package gas composition, treatment time, post-treatment storage, and ham formulation on L. monocytogenes inactivation efficacy of ACP. Results of present study will be helpful to optimize in-package ACP treatment and storage conditions to reduce L. monocytogenes, while maintaining the quality of ham.


Assuntos
Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Produtos da Carne/microbiologia , Gases em Plasma/farmacologia , Animais , Bacteriocinas/farmacologia , Contagem de Colônia Microbiana , Contaminação de Alimentos/análise , Embalagem de Alimentos/instrumentação , Conservação de Alimentos/instrumentação , Conservantes de Alimentos/farmacologia , Armazenamento de Alimentos , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Produtos da Carne/análise , Lactato de Sódio/farmacologia , Suínos
7.
Virology ; 543: 54-62, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32056847

RESUMO

Hantaviruses are rodent-borne hemorrhagic fever viruses leading to serious diseases. Viral attachment and entry represent the first steps in virus transmission and are promising targets for antiviral therapeutic intervention. Here we investigated receptor use in human airway epithelium of the Old and New World hantaviruses Hantaan virus (HTNV) and Andes virus (ANDV). Using a biocontained recombinant vesicular stomatitis virus pseudotype platform, we provide first evidence for a role of the cellular phosphatidylserine (PS) receptors of the T-cell immunoglobulin and mucin (TIM) protein family in HTNV and ANDV infection. In line with previous studies, HTNV, but not ANDV, was able to use glycosaminoglycan heparan sulfate and αvß3 integrin as co-receptors. In sum, our studies demonstrate for the first time that hantaviruses make use of apoptotic mimicry for infection of human airway epithelium, which may explain why these viruses can easily break the species barrier.


Assuntos
Vírus Hantaan/metabolismo , Hantavirus/metabolismo , Glicoproteínas de Membrana/metabolismo , Receptores de Superfície Celular/metabolismo , Receptores Virais/metabolismo , Mucosa Respiratória/virologia , Proteínas do Envelope Viral/metabolismo , Animais , Bacteriocinas/farmacologia , Linhagem Celular Tumoral , Células Epiteliais/metabolismo , Células Epiteliais/virologia , Vírus Hantaan/efeitos dos fármacos , Vírus Hantaan/patogenicidade , Vírus Hantaan/fisiologia , Hantavirus/fisiologia , Haplorrinos , Heparitina Sulfato/farmacologia , Receptor Celular 1 do Vírus da Hepatite A/metabolismo , Humanos , Integrinas/metabolismo , Proteínas de Membrana/metabolismo , Mimetismo Molecular , Peptídeos/farmacologia , Proteínas Proto-Oncogênicas/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Mucosa Respiratória/metabolismo , Vesiculovirus/metabolismo , Vesiculovirus/fisiologia
8.
Food Chem ; 314: 126244, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31982854

RESUMO

A novel bacteriocin CAMT2, produced by Bacillus amyloliquefaciens ZJHD3-06, has potential as a natural biopreservative for the control of food-borne spoilage and pathogenic bacteria. To avoid interaction of CAMT2 with components of food that may adversely impact its antibacterial activity, CAMT2 was encapsulated into nanovesicles prepared from soybean phosphatidylcholine. The encapsulation of CAMT2 exhibited a limited impact on functional structure and crystallinity of bacteriocin CAMT2, but a high anti-listerial activity in agar, and increase its stability in food at refrigeration temperature (4 °C). The results also showed that both encapsulated and free CAMT2 had good anti-listerial effect in skim milk at refrigeration temperature. However, encapsulated CAMT2 performed better than free CAMT2 against Listeria in whole milk. These results showed that nano-encapsulation is an effective method of protecting bacteriocin from fat in milk and retaining its antimicrobial efficacy.


Assuntos
Bacillus amyloliquefaciens/química , Bacteriocinas/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Leite/microbiologia , Nanoestruturas/química , Animais , Fosfatidilcolinas
9.
FASEB J ; 34(1): 1018-1037, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31914603

RESUMO

Recombinant antimicrobial peptide microcin J25 (MccJ25) causes potent antimicrobial activity against enterotoxigenic Escherichia coli (ETEC) in vitro; however, independently of this activity, its role in suppressing intestinal inflammation and epithelial barrier injury in vivo remains unclear. We investigated the therapeutic effects of MccJ25 on intestinal inflammation and epithelial barrier dysfunction and the underlying mechanism, using gentamicin for comparison. In a mouse model of intestinal inflammation, therapeutic administration of either MccJ25 or gentamicin after ETEC K88 infection attenuated clinical symptoms, reduced intestinal pathogen colonization, improved intestinal morphology, and decreased inflammatory pathologies and intestinal permeability, ultimately improving the hosts' health. MccJ25 also attenuated ETEC-induced mouse intestinal barrier dysfunction by enhancing tight junction proteins (TJPs). Using the human epithelial cell line Caco-2, we verified the epithelial barrier-strengthening and mucosal injury-alleviating effects of MccJ25 on ETEC infection: increased expression of TJPs by activating the p38/MAPK pathway, balancing the microbiota, and improving short-chain fatty acid concentrations in the cecum of ETEC-infected mice. Although gentamicin and MccJ25 had similar effects in the inflamed gut, MccJ25 was superior to gentamicin with regard to defending the host from ETEC infection. Overall, MccJ25 may be a promising therapeutic drug for treating enteric pathogen-induced intestinal inflammation diseases.


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Bacteriocinas/farmacologia , Epitélio/efeitos dos fármacos , Infecções por Escherichia coli/imunologia , Inflamação/imunologia , Mucosa Intestinal/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Células CACO-2 , Citocinas/metabolismo , Escherichia coli Enterotoxigênica , Feminino , Microbioma Gastrointestinal , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes/farmacologia
10.
Arch Microbiol ; 202(4): 755-763, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31807807

RESUMO

Thuricin 4AJ1, produced by Bacillus thuringiensis strain 4AJ1, showed inhibition activity against Bacillus cereus 0938 and ATCC 10987. It began to appear in the stationary phase and reached its maximum activity level of 209.958 U at 18 h against B. cereus 0938 and 285.689 U at 24 h against B. cereus ATCC 10987. Tricine-SDS-PAGE results showed that the partly purified thuricin 4AJ1 was about 6.5 kDa. The molecular weights of the known B. thuringiensis bacteriocins and the ones obtained by the two mainstream websites for predicting bacteriocins were inconsistent with the size of the thuricin 4AJ1, indicating that the bacteriocin obtained in this study may have a novel structure. Based on the biochemical properties, the thuricin 4AJ1 activities increased after treatment with proteinase K and lipase II, and were not affected by a-amylase, catalase, α-chymotrypsin VII and α-chymotrypsin II. It was heat tolerant, being active up to 90º C. In the pH 3-10 range, it maintained most of its activity. Finally, the sensitivity of the strain 4AJ1 to commonly used antibiotics was tested. In view of its stability and antibacterial activity, thuricin 4AJ1 may be applied as a food biopreservative.


Assuntos
Bacillus thuringiensis/metabolismo , Bacteriocinas/isolamento & purificação , Antibacterianos/farmacologia , Bacillus cereus/efeitos dos fármacos , Bacillus thuringiensis/química , Bacteriocinas/química , Bacteriocinas/farmacologia , Eletroforese em Gel de Poliacrilamida , Microbiologia de Alimentos , Peso Molecular
11.
J Appl Microbiol ; 128(2): 458-472, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31623015

RESUMO

AIMS: We aimed to evaluate some specific conditions for growth of Pediococcus pentosaceus ST65ACC and its bacteriocin expression through ABC transporters; to purify the bacteriocin and determine its sequence; and to evaluate the cytotoxicity potential of the purified bacteriocin(s). METHODS AND RESULTS: The results presented for growth behaviour of P. pentosaceus ST65ACC showed that the bacterial growth was slightly influenced when cultured in MRS broth with different amounts of inoculum: 1, 2, 5 and 10%. The bacteriocin activity increased when 5 and 10% inocula were used. The carbon source (glucose) used in different amounts (1, 2, 3 or 4%) had no significant effect on growth and bacteriocin production. The studied strain P. pentosaceus ST65ACC was able to metabolize xylooligosaccharide (XOS) as the sole carbon source, resulting in the production of an antimicrobial peptide. The genes involved in the ABC transport system and sugar metabolism of P. pentosaceus ST65ACC were expressed at different levels. The bacteriocin produced by P. pentosaceus ST65ACC was partially purified by precipitation with ammonium sulphate (40% saturation), followed by reversed-phase liquid chromatography, resulting in the identification of an active bacteriocin. Tandem mass spectrometry was used to identify the partial sequence KYYGNGVTCGKHSCSVDWGK sharing high similarity to coagulin A. The semi-purified bacteriocin had low cytotoxicity based on estimated values for maximal nontoxic concentration (MNC) and cytotoxicity concentration (CC50 ). CONCLUSIONS: The bacteriocin produced by P. pentosaceus ST65ACC is similar to coagulin, with low cytotoxicity, strong antimicrobial activity and possible additional metabolite routes in the producer cell. In addition to MRS broth, bacteriocin was produced also in medium containing XOS (as the single carbon source). SIGNIFICANCE AND IMPACT OF THE STUDY: To the best of our knowledge, this is the first report of evaluation of the role of ABC transporters in the expression of bacteriocin by P. pentosaceus, cultured in MRS and XOS.


Assuntos
Bacteriocinas/genética , Queijo/microbiologia , Leite/microbiologia , Pediococcus pentosaceus/metabolismo , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Bacteriocinas/biossíntese , Bacteriocinas/isolamento & purificação , Bacteriocinas/farmacologia , Expressão Gênica , Concentração de Íons de Hidrogênio , Pediococcus pentosaceus/química , Pediococcus pentosaceus/genética , Pediococcus pentosaceus/crescimento & desenvolvimento
12.
PLoS One ; 14(12): e0224431, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31841519

RESUMO

Dieback disease caused by Erwinia mallotivora is a major threat to papaya plantation in Malaysia. The current study was conducted to evaluate the potential of endophytic lactic acid bacteria (LAB) isolated from papaya seeds for disease suppression of papaya dieback. Two hundred and thirty isolates were screened against E. mallotivora BT-MARDI, and the inhibitory activity of the isolates against the pathogen was ranging from 11.7-23.7 mm inhibition zones. The synergistic experiments revealed that combination of W. cibaria PPKSD19 and Lactococcus lactis subsp. lactis PPSSD39 increased antibacterial activity against the pathogen. The antibacterial activity was partially due to the production of bacteriocin-like inhibitory substances (BLIS). The nursery experiment confirmed that the application of bacterial consortium W. cibaria PPKSD19 and L. lactis subsp. lactis PPSSD39 significantly reduced disease severity to 19% and increased biocontrol efficacy to 69% of infected papaya plants after 18 days of treatment. This study showed that W. cibaria PPKSD19 and L. lactis subsp. lactis PPSSD39 are potential candidate as biocontrol agents against papaya dieback disease.


Assuntos
Bacteriocinas/farmacologia , Carica/efeitos dos fármacos , Erwinia/efeitos dos fármacos , Antibacterianos , Antibiose/efeitos dos fármacos , Bactérias/efeitos dos fármacos , Fenômenos Biológicos , Carica/metabolismo , Erwinia/patogenicidade , Microbiologia de Alimentos , Lactobacillales/efeitos dos fármacos , Malásia , Sementes/efeitos dos fármacos
13.
Biocontrol Sci ; 24(4): 185-192, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31875610

RESUMO

Lactic Acid Bacteria (LAB) are generally recognized as safe. It has been used to increase the shelf-life of fermented products, and its antimicrobial action is based on the metabolites secretions, such as lactic acid, hydrogen peroxide, reuterin, bacteriocins and the like-bacteriocins substances. It has been proven that LAB are able to inhibit deteriorating bacteria of raw meat, but improper handling of live cultures could lead to spoilage. So, the use of their bacteriocins, small antimicrobial peptides, could be an alternative. Besides reducing the number of spoilage bacteria, it seeks to inhibit pathogenic bacteria such as Salmonella, enterohemorrhagic Escherichia coli and Listeria. The food industry uses few bacteriocins and now bacterial resistance has been reported. For that reason, the search of novel bacteriocins produced by LAB is a priority. Moreover, the natural microbiota of meat could be a reservoir of LAB.


Assuntos
Microbiologia de Alimentos , Armazenamento de Alimentos/métodos , Lactobacillales/fisiologia , Carne/microbiologia , Animais , Bacteriocinas/metabolismo , Bacteriocinas/farmacologia , Bacteriocinas/toxicidade , Resistência Microbiana a Medicamentos , Contaminação de Alimentos/prevenção & controle , Conservação de Alimentos/métodos , Conservantes de Alimentos/metabolismo , Conservantes de Alimentos/farmacologia , Conservantes de Alimentos/toxicidade , Inocuidade dos Alimentos/métodos , Humanos , Produtos da Carne/microbiologia , Microbiota/fisiologia , Carne Vermelha/microbiologia
14.
Appl Microbiol Biotechnol ; 103(23-24): 9607-9618, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31713671

RESUMO

The present paper describes the generation of derivatives from the hybrid peptide called Ent35-MccV, active against Gram-positive and Gram-negative bacteria. This peptide has a triple glycine hinge region between enterocin CRL35 and microcin V. In order to obtain variants of Ent35-MccV with greater biotechnological potential, a saturation mutagenesis was carried out in the hinge region. As a result, we obtained a bank of E. coli strains expressing different mutated hybrid bacteriocins in the central position of the hinge region. From all these variants, we found that the one bearing a tyrosine in the central region of the hinge (Ent35-GYG-MccV) is 2-fold more active against E. coli and 4-fold more active against Listeria than the original peptide Ent35-MccV. This derivative was purified and characterized. The development and evaluation of alternative hinges for Ent35-MccV represents a step forward in the bioengineering of antimicrobial peptides. This approach fosters the rational design of peptides with enhanced antimicrobial activity.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Bacteriocinas/farmacologia , Escherichia coli/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos , Sequência de Aminoácidos , Anti-Infecciosos/metabolismo , Bacteriocinas/genética , Bacteriocinas/metabolismo , Viabilidade Microbiana/efeitos dos fármacos , Mutagênese Sítio-Dirigida , Mutação , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes de Fusão/farmacologia
15.
Cell Host Microbe ; 26(5): 691-701.e5, 2019 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-31726031

RESUMO

Understanding the role of the microbiota components in either preventing or favoring enteric infections is critical. Here, we report the discovery of a Listeria bacteriocin, Lmo2776, which limits Listeria intestinal colonization. Oral infection of conventional mice with a Δlmo2776 mutant leads to a thinner intestinal mucus layer and higher Listeria loads both in the intestinal content and deeper tissues compared to WT Listeria. This latter difference is microbiota dependent, as it is not observed in germ-free mice. Strikingly, it is phenocopied by pre-colonization of germ-free mice before Listeria infection with Prevotella copri, an abundant gut-commensal bacteria, but not with the other commensals tested. We further show that Lmo2776 targets P. copri and reduces its abundance. Together, these data unveil a role for P.copri in exacerbating intestinal infection, highlighting that pathogens such as Listeria may selectively deplete microbiota bacterial species to avoid excessive inflammation.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Listeria monocytogenes/metabolismo , Listeriose/prevenção & controle , Prevotella/crescimento & desenvolvimento , Animais , Feminino , Microbioma Gastrointestinal/genética , Microbioma Gastrointestinal/fisiologia , Vida Livre de Germes , Humanos , Inflamação/prevenção & controle , Listeriose/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Prevotella/efeitos dos fármacos
16.
Int J Mol Sci ; 20(20)2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31627419

RESUMO

In this study, microcin J25, a potent antimicrobial lasso peptide that acts on Gram-negative bacteria, was subjected to a harsh treatment with a base in order to interrogate its stability and mechanism of action and explore its structure-activity relationship. Despite the high stability reported for this lasso peptide, the chemical treatment led to the detection of a new product. Structural studies revealed that this product retained the lasso topology, but showed no antimicrobial activity due to the epimerization of a key residue for the activity. Further microbiological assays also demonstrated that it showed a high synergistic effect with colistin.


Assuntos
Anti-Infecciosos/química , Bacteriocinas/química , Anti-Infecciosos/farmacologia , Bacteriocinas/farmacologia , Colistina/química , Colistina/farmacologia , Sinergismo Farmacológico , Testes de Sensibilidade Microbiana , Estabilidade Proteica
17.
Mol Biol Rep ; 46(6): 6501-6512, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31583564

RESUMO

Enteropathogenic Escherichia coli (EPEC) is one of the resistance bacteria towards antibiotics and have been raising problem during treatments. Therefore, a new antibiotic candidate is required. Plantaricin E and F recombinant have been successfully produced by a GRAS host Lactococcus lactis. This study was aimed to evaluate the efficacy and toxicity of plantaricin E and F recombinant against EPEC K1.1 infection by in vivo assay. The production of plantaricin E and F recombinants from Lactococcus lactis was conducted and encapsulated. The in vivo study was carried out by inoculating the mice perorally with EPEC K1.1 for 7 days then treated with 100, 250, and 500 mg/kg body weight/day of recombinant plantaricin E and F for another 7 days. The toxicity assay were observed in ddY mice using various concentrations of treatment (50, 100, 1000, and 5000 mg/kg/body weight) doses perorally for 48 h. The result showed that the plantaricin E and F recombinant were successfully produced in Lactococcus lactis expression host with 3.7 kDa and 3.8 kDa in size. The efficacy study revealed the optimal doses of plantaricin E and F recombinant against EPEC K1.1 infection was 250 mg/kgBW for plantaricin E and 500 mg/kgBW for plantaricin F. The plantarisin E and F recombinant treatment showed improvement in leukocyte, hematocrit, and hemoglobin levels as well in decreasing malondialdehyde (MDA) level. Observation of the intestine histopathology showed small amounts of mononuclear inflammatory cell infiltration than the other groups of treatment. The acute toxicity assay showed that there was no mortality observed during the assay, even after 5000 mg/kg body weight of plantarisin E and F recombinant treatment (LD50 > 5000 mg/KgBW). The hematological and biochemical observations showed normal levels in leukocytes, erythrocytes, hematocrit, hemoglobin, platelets, urea, creatinine, and alanine transaminase aspartate transaminase (SGOT and SGPT) while histopathological observation shows a picture of normal liver and kidney cells. This study confirmed the application of bacteriocin for further academic and industrial purposes as a non-toxic substance for food preservative and antibiotic candidate.


Assuntos
Antibacterianos/administração & dosagem , Antioxidantes/administração & dosagem , Bacteriocinas/administração & dosagem , Escherichia coli Enteropatogênica/efeitos dos fármacos , Infecções por Escherichia coli/tratamento farmacológico , Lactococcus lactis/metabolismo , Administração Oral , Animais , Antibacterianos/farmacologia , Antioxidantes/farmacologia , Bacteriocinas/genética , Bacteriocinas/farmacologia , Cápsulas , Modelos Animais de Doenças , Infecções por Escherichia coli/metabolismo , Microbiologia de Alimentos , Células HeLa , Humanos , Lactococcus lactis/genética , Masculino , Malondialdeído/metabolismo , Camundongos , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia
18.
Can J Microbiol ; 65(12): 895-903, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31479619

RESUMO

Bacteriocins are antimicrobial peptides, produced by Gram-positive bacteria such as lactococci and staphylococci, that have limited bactericidal action against Gram-negative bacteria. The aim of this paper was to study the sensitivity of three strains of Escherichia coli to bacteriocins: nisin (as Nisaplin®) and two staphylococcal peptides (warnerin and hominin) during sucrose-induced osmotic stress. We found that all peptides in a 0.3 g·mL-1 sucrose solution significantly reduced the number of viable E. coli. The most pronounced antibacterial effect was achieved by nisin against E. coli K-12 (3 log reduction). Slightly less bactericidal effects were observed with warnerin (1 mg·mL-1) and hominin (1 mg·mL-1) in sucrose solution. The lytic activity of staphylococcal peptides was detected by decreased optical density and viable cell counts. Moreover, it was confirmed by the increased amount of DNA and protein in the medium and the morphological changes detected by atomic force microscopy after 20 h of treatment. Zymographic analysis revealed the release of lytic enzymes from E. coli cells after treatment with staphylococcal peptides and sucrose. These results indicated that the antimicrobial action of peptides can be extended to Gram-negative bacteria via combination with high concentrations of sucrose.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Escherichia coli/efeitos dos fármacos , Pressão Osmótica , Sacarose/farmacologia , Antibacterianos/metabolismo , Bacteriocinas/metabolismo , Bacteriólise/efeitos dos fármacos , Bactérias Gram-Positivas/metabolismo , Viabilidade Microbiana/efeitos dos fármacos
19.
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
20.
Nature ; 572(7771): 665-669, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31435014

RESUMO

Intestinal commensal bacteria can inhibit dense colonization of the gut by vancomycin-resistant Enterococcus faecium (VRE), a leading cause of hospital-acquired infections1,2. A four-strained consortium of commensal bacteria that contains Blautia producta BPSCSK can reverse antibiotic-induced susceptibility to VRE infection3. Here we show that BPSCSK reduces growth of VRE by secreting a lantibiotic that is similar to the nisin-A produced by Lactococcus lactis. Although the growth of VRE is inhibited by BPSCSK and L. lactis in vitro, only BPSCSK colonizes the colon and reduces VRE density in vivo. In comparison to nisin-A, the BPSCSK lantibiotic has reduced activity against intestinal commensal bacteria. In patients at high risk of VRE infection, high abundance of the lantibiotic gene is associated with reduced density of E. faecium. In germ-free mice transplanted with patient-derived faeces, resistance to VRE colonization correlates with abundance of the lantibiotic gene. Lantibiotic-producing commensal strains of the gastrointestinal tract reduce colonization by VRE and represent potential probiotic agents to re-establish resistance to VRE.


Assuntos
Bacteriocinas/metabolismo , Bacteriocinas/farmacologia , Enterococcus faecium/efeitos dos fármacos , Lactococcus lactis/metabolismo , Probióticos , Resistência a Vancomicina/efeitos dos fármacos , Enterococos Resistentes à Vancomicina/efeitos dos fármacos , Animais , Antibacterianos/biossíntese , Antibacterianos/isolamento & purificação , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Bacteriocinas/genética , Bacteriocinas/isolamento & purificação , Enterococcus faecium/crescimento & desenvolvimento , Enterococcus faecium/isolamento & purificação , Fezes/microbiologia , Feminino , Trato Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/microbiologia , Vida Livre de Germes , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/crescimento & desenvolvimento , Humanos , Lactococcus lactis/química , Lactococcus lactis/crescimento & desenvolvimento , Lactococcus lactis/fisiologia , Camundongos , Testes de Sensibilidade Microbiana , Microbiota/genética , Nisina/química , Nisina/farmacologia , Simbiose/efeitos dos fármacos , Vancomicina/farmacologia , Enterococos Resistentes à Vancomicina/crescimento & desenvolvimento , Enterococos Resistentes à Vancomicina/isolamento & purificação
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