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1.
Pak J Biol Sci ; 25(9): 796-802, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36098081

RESUMO

<b>Background and Objective:</b> Preservation using antimicrobials has been observed to inhibit the growth of pathogenic bacteria in food. Nowadays many people choose food preservatives that are safe for health and natural. Bacteriocins as food preservatives are safe because antimicrobials from the antimicrobial peptide group include GRAS (Generally Recognized As Safe). Bacteriocin-producing LAB can be found in various fermented foods, one of which is "Dadih". Bacteriocins are expected to inhibit the growth of pathogenic bacteria so that they can be developed as an alternative to food preservatives. <b>Materials and Methods:</b> In this study, all experiments were performed with two replicates and the results were expressed as Mean±Standard Deviation (SD). <b>Results:</b> Screening results showed that the DK8 isolate had the highest antimicrobial activity. The DK8 isolate was identified molecularly using 16s RNA sequencing, showing that the DK8 isolate had the highest similarity to <i>Lactobacillus pentosus</i> strain 124-2. Bacteriocins from DK8 isolate and partially purified using ammonium sulfate precipitation at concentrations of 50, 60 and 70%. The addition of ammonium sulfate with a concentration of 50% showed the highest antimicrobial activity against <i>Salmonella</i> sp. (12.63 mm) and <i>Escherichia coli</i> (11.33 mm) while the highest antimicrobial activity against <i>Staphylococcus aureus</i> was the addition of 60% ammonium sulfate (8.13 mm). <b>Conclusion:</b> Lactic acid bacteria isolate was identified to have the highest similarity with <i>Lactobacillus pentosus</i> strain 124-2 and precipitation using 50% ammonium sulfate showed the highest antimicrobial activity.


Assuntos
Anti-Infecciosos , Bacteriocinas , Lactobacillus pentosus , Sulfato de Amônio , Anti-Infecciosos/farmacologia , Bacteriocinas/farmacologia , Escherichia coli , Conservantes de Alimentos/farmacologia , Humanos
2.
World J Microbiol Biotechnol ; 38(12): 220, 2022 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-36083397

RESUMO

Traditionally fermented foods and beverages are still produced and consumed at a large scale in Romania. They are rich sources for novel lactic acid bacteria with functional properties and with potential application in food industry or health. Lactobacillus helveticus 34.9, isolated from a home-made fermented milk is able to inhibit the growth of other bacteria, such as other lactic acid bacteria, but also strains of Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, and Halobacillus hunanensis, a halobacterium isolated from the degraded wall of a Romanian monastery. L. helveticus 34.9 produces a large bacteriocin (35 KDa), active in a wide pH range, but inactivated by heat and proteinase K treatment. It shares about 20% sequence coverage with helveticin J, as determined by LC-MS analysis. Bacteriocin production was enhanced under stress conditions, especially when combined stresses were applied. Its mode of action and degree of inhibition depended on the concentration and on the indicator strain that was used; L. delbrueckii subsp. bulgaricus LMG 6901T cells from a suspension were killed, but the viability of H. hunanensis 5Hum cells was only reduced to 60%, within 8 h. However, the bacteriocin was able to prevent the bacterial growth of both indicator strains when added to the cultivation medium prior inoculation. Scanning electron microscopy images revealed morphological changes induced by the bacteriocin treatment in both sensitive strains, but more severe in the case of L. delbrueckii subsp. bulgaricus. Due to the broad antibacterial spectrum and its production under various stress conditions, the bacteriocin or the producing strain may find application in health, food and non-food related fields, including in the restoration of historical buildings.


Assuntos
Bacteriocinas , Lactobacillus helveticus , Antibacterianos/farmacologia , Bacteriocinas/metabolismo , Lactobacillus helveticus/metabolismo , Staphylococcus aureus/metabolismo
3.
ACS Synth Biol ; 11(9): 3078-3087, 2022 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-36065523

RESUMO

Mersacidin is an antimicrobial class II lanthipeptide. Lanthipeptides are a class of ribosomally synthesized and post-translationally modified peptides (RiPPs), characterized by intramolecular lanthionine rings. These rings give lanthipeptides their bioactive structure and stability. RiPPs are produced from a gene cluster that encodes a precursor peptide and its dedicated unique modification enzymes. The field of RiPP engineering aims to recombine modification enzymes from different RiPPs to modify new substrates, resulting in new-to-nature molecules with novel or improved functionality. The enzyme MrsM from the mersacidin gene cluster installs the four lanthionine rings of mersacidin, including the uniquely small ring A. By applying MrsM in RiPP engineering, this ring could be installed in linear peptides to achieve stabilization by a very small lanthionine or to create small lanthionine-stabilized modules for chemical modification. However, the formation of unique intramolecular structures like that of mersacidin's ring A can be very stringent. Here, the formation of ring A of mersacidin is characterized by mutagenesis. A range of truncated mersacidin variants was made to identify the smallest possible construct in which this ring could still be formed. Additionally, mutants were created to study the flexibility of ring A formation. It was found that although the formation of ring A is stringent, it can be formed in a core peptide as small as five amino acids. The truncated mersacidin core peptide CTFAL is the smallest ribosomally produced lanthipeptide reported to date, and it has exciting prospects as a new module for application in RiPP engineering.


Assuntos
Bacteriocinas , Alanina/análogos & derivados , Alanina/metabolismo , Bacteriocinas/genética , Bacteriocinas/metabolismo , Peptídeos/metabolismo , Sulfetos
4.
Food Res Int ; 160: 111640, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36076376

RESUMO

The potential probiotic function of Latilactobacills curvatus has attracted the attention of researchers. To explore the differences in the genomes of L. curvatus, nine strains were isolated from various sources, including feces and fermented vegetables and compared with 25 strains from the NCBI database. The findings indicated that the average genome size, GC content, and CDS of L. curvatus were 1.94 MB, 41.9%, and 1825, respectively. Its core genome is associated with transcription, translation, carbohydrate transport and metabolism, and defense functions. The pan-genome of L. curvatus was in a closed state. The genetic diversity of L. curatus is mainly manifested in its ability to use carbohydrates, antibiotic resistance, bacteriocin operon, and polymeric regularly interspaced short palindromic repeats (CRISPR)-Cas for bacterial immunity. The CRISPR system of 34 strains of L. curvatus was predominantly found to be of the IIA type with a few IIC and IE types. These findings will contribute to a better understanding of this species.


Assuntos
Bacteriocinas , Bacteriófagos , Bacteriocinas/genética , Bacteriófagos/genética , Sistemas CRISPR-Cas , Metabolismo dos Carboidratos/genética , Resistência Microbiana a Medicamentos , Genoma Bacteriano/genética , Genótipo , Fenótipo
5.
Molecules ; 27(17)2022 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-36080167

RESUMO

The important role of Lactiplantibacillus plantarum strains in improving the human mucosal and systemic immunity, preventing non-steroidal anti-provocative drug-induced reduction in T-regulatory cells, and as probiotic starter cultures in food processing has motivated in-depth molecular and genomic research of these strains. The current study, building on this research concept, reveals the importance of Lactiplantibacillus plantarum 13-3 as a potential probiotic and bacteriocin-producing strain that helps in improving the condition of the human digestive system and thus enhances the immunity of the living beings via various extracellular proteins and exopolysaccharides. We have assessed the stability and quality of the L. plantarum 13-3 genome through de novo assembly and annotation through FAST-QC and RAST, respectively. The probiotic-producing components, secondary metabolites, phage prediction sites, pathogenicity and carbohydrate-producing enzymes in the genome of L. plantarum 13-3 have also been analyzed computationally. This study reveals that L. plantarum 13-3 is nonpathogenic with 218 subsystems and 32,918 qualities and five classes of sugars with several important functions. Two phage hit sites have been identified in the strain. Cyclic lactone autoinducer, terpenes, T3PKS, and RiPP-like gene clusters have also been identified in the strain evidencing its role in food processing. Combined, the non-pathogenicity and the food-processing ability of this strain have rendered this strain industrially important. The subsystem and qualities characterization provides a starting point to investigate the strain's healthcare-related applications as well.


Assuntos
Bacteriocinas , Lactobacillus plantarum , Probióticos , Bacteriocinas/metabolismo , Microbiologia de Alimentos , Inocuidade dos Alimentos , Humanos , Lactobacillus plantarum/metabolismo , Probióticos/metabolismo
6.
Eur J Med Res ; 27(1): 173, 2022 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-36076252

RESUMO

OBJECTIVES: Staphylococcus aureus and Pseudomonas aeruginosa were the most common bacteria in nosocomial infections. Different bacteriocins are currently being studied as antibiotics or in conjunction with antibiotics as potential strategies to treat resistant infectious agents. The study aimed to determine nisin's effect on the biofilm production, antimicrobial susceptibility, and biofilm formation of S. aureus and P. aeruginosa. MATERIALS AND METHODS: The experimental research tested two antibiotic-resistant isolates of S. aureus and P. aeruginosa strains. The experimental study tested two antibiotic-resistant isolates of S. aureus and P. aeruginosa strains. The MIC of bacteriocin nisin was determined using the micro broth dilution method, and crystal violet was used to assess the effect of bacteriocin on the biofilm. In addition, L929 cell culture was used to determine the effectiveness of bacteriocin on the isolate under similar cell conditions. Moreover, the MTT assay was used to and evaluate bacteriocin toxicity. In this study, the software Prism version 9 and Graph pad software were utilized. RESULTS: The results of this study reveal that the nisin has different activities at different doses and is considered dose-dependent. At various times and doses, nisin inhibits biofilm formation in S. aureus, and P. aeruginosa isolates. Nisin also showed a decreasing survival of the isolates. Antibiotic-resistant bacteria can be made more vulnerable by nisin. Furthermore, nisin treatment affected the production of virulence factors such as hemolysins in S. aureus and had little or a negative effect on P. aeruginosa virulence factors. This medication stops S. aureus and P. aeruginosa from growing and causes bacterial cell damage. CONCLUSIONS: Antibacterial properties of nicin against S. aureus and P. aeruginosa were successfully studied. This bacteriocin stops S. aureus and P. aeruginosa from growing and causes bacterial cell damage or death. Damage to the membrane among the fundamental causes is reduced membrane potential and enzyme inactivation.


Assuntos
Bacteriocinas , Nisina , Infecções Estafilocócicas , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bacteriocinas/farmacologia , Bacteriocinas/uso terapêutico , Biofilmes , Humanos , Testes de Sensibilidade Microbiana , Nisina/farmacologia , Nisina/uso terapêutico , Pseudomonas aeruginosa , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus , Fatores de Virulência/farmacologia , Fatores de Virulência/uso terapêutico
7.
Proc Natl Acad Sci U S A ; 119(38): e2205407119, 2022 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-36099299

RESUMO

A key property of many antibiotics is that they will kill or inhibit a diverse range of microbial species. This broad-spectrum of activity has its evolutionary roots in ecological competition, whereby bacteria and other microbes use antibiotics to suppress other strains and species. However, many bacteria also use narrow-spectrum toxins, such as bacteriocins, that principally target conspecifics. Why has such a diversity in spectrum evolved? Here, we develop an evolutionary model to understand antimicrobial spectrum. Our first model recapitulates the intuition that broad-spectrum is best, because it enables a microbe to kill a wider diversity of competitors. However, this model neglects an important property of antimicrobials: They are commonly bound, sequestered, or degraded by the cells they target. Incorporating this toxin loss reveals a major advantage to narrow-spectrum toxins: They target the strongest ecological competitor and avoid being used up on less important species. Why then would broad-spectrum toxins ever evolve? Our model predicts that broad-spectrum toxins will be favored by natural selection if a strain is highly abundant and can overpower both its key competitor and other species. We test this prediction by compiling and analyzing a database of the regulation and spectrum of toxins used in inter-bacterial competition. This analysis reveals a strong association between broad-spectrum toxins and density-dependent regulation, indicating that they are indeed used when strains are abundant. Our work provides a rationale for why bacteria commonly evolve narrow-spectrum toxins such as bacteriocins and suggests that the evolution of antibiotics proper is a signature of ecological dominance.


Assuntos
Bacteriocinas , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Bactérias/genética , Bactérias/metabolismo , Bacteriocinas/metabolismo , Seleção Genética
8.
Microb Cell Fact ; 21(1): 194, 2022 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-36123739

RESUMO

BACKGROUND: Due to the detrimental effects of chemical preservatives, there has been an increasing demand for safer, healthier and natural bio-preservatives. Bacteriocins have attracted increasing interest because of their potential as natural bio-preservatives. RESULTS: We screened a large number of Bacillus thuringiensis strains and isolated one strain (B. thuringiensis P86) with antimicrobial activity against several foodborne pathogens. Three novel leaderless bacteriocins, including thucin A1, thucin A2 and thucin A3, were purified and identified from the culture supernatant of B. thuringiensis P86, whose molecular masses were 5552.02, 5578.07 and 5609.06 Da, respectively. Thucin A1 was then selected as a representative to be tested, and it exhibited potent inhibitory activity against all tested gram-positive bacteria. More importantly, thucin A1 showed stronger antimicrobial activity than nisin A against two important foodborne pathogens Bacillus cereus and Listeria monocytogenes. In addition, thucin A1 exhibited strong acid-base adaptability (pH 2-11), high endurance to heat, good stability to trypsin and pepsin, no hemolysis activity and cytotoxicity, and could effectively inhibit or eliminate Bacillus cereus and Listeria monocytogenes in skim milk. CONCLUSIONS: Our findings indicate that these novel leaderless bacteriocins are potentially promising food biopreservatives.


Assuntos
Anti-Infecciosos , Bacteriocinas , Listeria monocytogenes , Anti-Infecciosos/farmacologia , Bacillus cereus , Bacteriocinas/química , Bactérias Gram-Positivas , Testes de Sensibilidade Microbiana , Pepsina A/farmacologia , Tripsina
9.
ACS Chem Biol ; 17(9): 2519-2527, 2022 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-36044589

RESUMO

Lanthipeptides are ribosomally synthesized and post-translationally modified peptides characterized by lanthionine (Lan) and/or methyllanthionine (MeLan) residues. Four classes of enzymes have been identified to install these structures in a substrate peptide. Recently, a novel class of lanthipeptides was discovered that lack genes for known class I-IV lanthionine synthases in their biosynthetic gene cluster (BGC). In this study, the dehydration of Ser/Thr during the biosynthesis of the class V lanthipeptide cacaoidin was reconstituted in vitro. The aminoglycoside phosphotransferase-like enzyme CaoK iteratively phosphorylates Ser/Thr residues on the precursor peptide CaoA, followed by phosphate elimination catalyzed by the HopA1 effector-like protein CaoY to achieve eight successive dehydrations. CaoY shows sequence similarity to the OspF family proteins and the lyase domains of class III/IV lanthionine synthetases, and mutagenesis studies identified residues that are critical for catalysis. An AlphaFold prediction of the structure of the dehydration enzyme complex engaged with its substrate suggests the importance of hydrophobic interactions between the CaoA leader peptide and CaoK in enzyme-substrate recognition. This model is supported by site-directed mutagenesis studies.


Assuntos
Bacteriocinas , Liases , Alanina/análogos & derivados , Bacteriocinas/metabolismo , Desidratação , Humanos , Canamicina Quinase/metabolismo , Ligases/metabolismo , Liases/metabolismo , Peptídeos/química , Fosfatos , Sinais Direcionadores de Proteínas , Sulfetos
10.
Pak J Pharm Sci ; 35(4): 1125-1134, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36008911

RESUMO

Lactic acid bacteria are microorganisms that can be present in meat, milk and fermented products, as well as fermented drinks and vegetables, and they inhibit the growth of pathogenic and decaying microorganisms. Our aim was isolating, screening, characterization and estimation of bacteriocin/s of Lactic acid bacteria isolated from Horses milk in Jeddah city, Saudi Arabia. That have antagonistic activity against a wide range of pathogenic bacteria. On MRS agar medium 16 LAB isolates were examined using the agar well diffusion method against the pathogenic bacteria (Gram-positive bacteria: S. aureus ATCCBAA977, ST. Pneumonia ATCC49619) and (Gram-negative bacteria: E. coli ATCC35218, P. aeruginosa ATCC27853). The results showed that 12 isolates out of 16 isolates (75%) worked to inhibit all types of pathogenic bacteria used. The best isolate was identified using molecular methods; the results showed that the isolate (H6) matched 100% with (Enterococcus faecium LR135401.1). This isolate produced the highest bacteriocin at 35°C/24 h/pH (6.5).


Assuntos
Bacteriocinas , Enterococcus faecium , Lactobacillales , Ágar , Animais , Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Escherichia coli , Cavalos , Leite/microbiologia , Staphylococcus aureus
11.
Microbiologyopen ; 11(4): e1308, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36031956

RESUMO

Bacteriophages infecting dairy starter bacteria are a leading cause of milk fermentation failure and strategies to reduce the risk of phage infection in dairy settings are demanded. Along with dairy starters, bacteriocin producers (protective cultures) or the direct addition of bacteriocins as biopreservatives may be applied in food to extend shelf-life. In this work, we have studied the progress of infection of Lactococcus cremoris MG1363 by the phage sk1, in the presence of three bacteriocins with different modes of action: nisin, lactococcin A (LcnA), and lactococcin 972 (Lcn972). We aimed to reveal putative bacteriocin-phage interactions (BaPI) that could be detrimental and increase the risk of fermentation failure due to phages. Based on infections in broth and solid media, a synergistic effect was observed with Lcn972. This positive sk1-Lcn972 interaction could be correlated with an increased burst size. sk1-Lcn972 BaPI occurred independently of a functional SOS and cell envelope stress response but was lost in the absence of the major autolysin AcmA. Furthermore, BaPI was not exclusive to the sk1-Lcn972 pairing and could be observed with other phages and lactococcal strains. Therefore, bacteriocins may facilitate phage predation of dairy lactococci and their use should be carefully evaluated.


Assuntos
Bacteriocinas , Bacteriófagos , Lactococcus lactis , Fermentação , Lactococcus lactis/virologia
12.
Biomolecules ; 12(8)2022 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-36009048

RESUMO

The Gram-positive and spore-forming bacterium Brevibacillus laterosporus (Bl) belongs to the Brevibacillus brevis phylogenetic cluster. Isolates of the species have demonstrated pesticidal potency against a wide range of invertebrate pests and plant diseases. Two New Zealand isolates, Bl 1821L and Bl 1951, are under development as biopesticides for control of diamondback moth and other pests. However, due to the often-restricted growth of these endemic isolates, production can be an issue. Based on the previous work, it was hypothesised that the putative phages might be involved. During investigations of the cause of the disrupted growth, electron micrographs of crude lysate of Bl 1821L showed the presence of phages' tail-like structures. A soft agar overlay method with PEG 8000 precipitation was used to differentiate between the antagonistic activity of the putative phage and phage tail-like structures (bacteriocins). Assay tests authenticated the absence of putative phage activity. Using the same method, broad-spectrum antibacterial activity of Bl 1821L lysate against several Gram-positive bacteria was found. SDS-PAGE of sucrose density gradient purified and 10 kD MWCO concentrated lysate showed a prominent protein band of ~48 kD, and transmission electron microscopy revealed the presence of polysheath-like structures. N-terminal sequencing of the ~48 kD protein mapped to a gene with weak predicted amino acid homology to a Bacillus PBSX phage-like element xkdK, the translated product of which shared >90% amino acid similarity to the phage tail-sheath protein of another Bl published genome, LMG15441. Bioinformatic analysis also identified an xkdK homolog in the Bl 1951 genome. However, genome comparison of the region around the xkdK gene between Bl 1821L and Bl 1951 found differences including two glycine rich protein encoding genes which contain imperfect repeats (1700 bp) in Bl 1951, while a putative phage region resides in the analogous Bl 1821L region. Although comparative analysis of the genomic organisation of Bl 1821L and Bl 1951 PBSX-like region with the defective phages PBSX, PBSZ, and PBP 180 of Bacillus subtilis isolates 168 and W23, and Bacillus phage PBP180 revealed low amino acids similarity, the genes encode similar functional proteins in similar arrangements, including phage tail-sheath (XkdK), tail (XkdO), holin (XhlB), and N-acetylmuramoyl-l-alanine (XlyA). AMPA analysis identified a bactericidal stretch of 13 amino acids in the ~48 kD sequenced protein of Bl 1821L. Antagonistic activity of the purified ~48 kD phage tail-like protein in the assays differed remarkably from the crude lysate by causing a decrease of 34.2% in the number of viable cells of Bl 1951, 18 h after treatment as compared to the control. Overall, the identified inducible phage tail-like particle is likely to have implications for the in vitro growth of the insect pathogenic isolate Bl 1821L.


Assuntos
Bacillus , Bacteriocinas , Bacteriófagos , Aminoácidos/metabolismo , Animais , Bacteriófagos/genética , Bacteriófagos/metabolismo , Brevibacillus , Insetos , Filogenia
13.
Sci Rep ; 12(1): 13401, 2022 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-35927320

RESUMO

The current study aimed to figure out the effect of using a combination of 2% inulin, and 2% Fructo-oligosaccharides (FOS) with Lactobacillus acidophilus and their bacteriocin on some yogurt properties such as coagulation time, extending the shelf life of set yogurt and its microbiological quality, also the acceptance by consumers. The results indicated that coagulation time increased by 22.75% in yogurts prepared with Lactobacillus acidophilus and their bacteriocins compared to the control, and titratable acidity increased gradually in all treatments during storage. Hence control acidity (%) increased from 0.84 ± 0.02A at zero time to 1.23 ± 0.03A after 14 days of cold storage, while treatment (T4) was 0.72 ± 0.01C at zero time and reached 1.20 ± 0.5A after 39 days at the same conditions. The sensory properties showed the superiority of inulin, FOS, and Lactobacillus acidophilus bacteriocin groups. Lactobacillus bulgaricus, Streptococcus thermophiles, and Lactobacillus acidophilus count increased in the treatments compared to the control group, with an extended shelf life to 39 days of storage in the medicines containing lactobacillus acidophilus bacteriocin. Coliforms, Moulds, and yeasts did not detect in the treatments comprising 2% inulin, 2% FOS, and lactobacillus acidophilus bacteriocin for 39 days of refrigerated storage. This study proved that 2% inulin, 2% FOS, and Lactobacillus acidophilus bacteriocin fortification extended the shelf life by more than 5 weeks.


Assuntos
Bacteriocinas , Probióticos , Bacteriocinas/farmacologia , Inulina/farmacologia , Lactobacillus acidophilus , Oligossacarídeos/farmacologia , Probióticos/farmacologia , Iogurte/microbiologia
14.
J Agric Food Chem ; 70(32): 9990-9999, 2022 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-35924350

RESUMO

Bacteriocins are bacterial-derived peptides that exhibit antimicrobial activity and can be used as food preservatives. Here, using the indicator strain Bacillus cereus CMCC63301, we screened and identified a Bacillus thuringiensis LX43 strain that exhibits potent antimicrobial activity and harbors a putative leaderless bacteriocin gene cluster (thn gene cluster). Five novel leaderless bacteriocins, thuricin A1, A2, A3, A4, and A5, encoded by the thn gene cluster, were purified and identified. Thuricin A5 was regarded as a representative and showed remarkable antimicrobial activity against foodborne pathogens B. cereus, Clostridium perfringens, Listeria monocytogenes, and Staphylococcus aureus, likely by damaging their cell envelope. Moreover, thuricin A5 displayed good thermal and pH stability, with no hemolytic activity and cytotoxicity, indicating its wide applicability and biosafety. Furthermore, thuricin A5 effectively inhibited or eradicated foodborne pathogens in skim milk at 25 °C in a dose-dependent manner, affirming its potential for use as a novel biopreservative in foods.


Assuntos
Anti-Infecciosos , Bacillus thuringiensis , Bacteriocinas , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Bacillus cereus/genética , Bacteriocinas/genética , Bacteriocinas/farmacologia
15.
Microb Biotechnol ; 15(9): 2337-2350, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35849816

RESUMO

Pseudomonas sp. strain 166 was isolated from soil samples from Changbai Mountains. A novel bacteriocin PA166 from Pseudomonas sp. 166 was purified using ammonium sulfate, dextran gel chromatography column and Q-Sepharose column chromatography successively. The molecular mass of bacteriocin PA166 was found to be 49.38 kDa by SDS-PAGE and liquid chromatography-mass spectrometry (MS)/MS. Bacteriocin PA166 showed stability at a wide range of pH (2-10), and thermal stability (40, 60, 80 and 100°C). The bacteriocin PA166 antimicrobial activity was slightly inhibited by Ca2+ , K+ and Mg2+ . The minimum bactericidal concentrations of bacteriocin PA166 against five Pasteurella multocida strains ranged from 2 to 8 µg ml-1 . Bacteriocin PA166 showed low cytotoxicity and a higher treatment index (TI = 82.51). Fluorescence spectroscopy indicated that bacteriocin PA166 destroyed the cell membrane to exert antimicrobial activity. In summary, bacteriocin PA166 had strong antibacterial activity, high TI and low toxicity, and hence could serve as a potential clinical therapeutic drug.


Assuntos
Bacteriocinas , Antibacterianos/química , Bacteriocinas/farmacologia , Eletroforese em Gel de Poliacrilamida , Peso Molecular , Pseudomonas
16.
Gut Microbes ; 14(1): 2100203, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35877697

RESUMO

The gut microbiome is a vast reservoir of microbes, some of which produce antimicrobial peptides called bacteriocins that may inhibit specific bacteria associated with disease. Fusobacterium nucleatum is an emerging human bacterial pathogen associated with gastrointestinal diseases including colorectal cancer (CRC). In this study, fecal samples of healthy donors were screened for potential bacteriocin-producing probiotics with antimicrobial activity against F. nucleatum. A novel isolate, designated as Streptococcus salivarius DPC6993 demonstrated a narrow-spectrum of antimicrobial activity against F. nucleatum in vitro. In silico analysis of the S. salivarius DPC6993 genome revealed the presence of genes involved in the production of the bacteriocins salivaricin A5 and salivaricin B. After 6 h in a colon fermentation model, there was a significant drop in the number of F. nucleatum in samples that had been simultaneously inoculated with S. salivarius DPC6993 + F. nucleatum DSM15643 compared to those inoculated with F. nucleatum DSM15643 alone (mean ± SD: 9243.3 ± 3408.4 vs 29688.9 ± 4993.9 copies/µl). Furthermore, 16S rRNA amplicon analysis revealed a significant difference in the mean relative abundances of Fusobacterium between samples inoculated with both S. salivarius DPC6993 and F. nucleatum DSM15643 (0.05%) and F. nucleatum DSM15643 only (0.32%). Diversity analysis indicated minimal impact exerted by S. salivarius DPC6993 on the surrounding microbiota. Overall, this study highlights the ability of a natural gut bacterium to target a bacterial pathogen associated with CRC. The specific targeting of CRC-associated pathogens by biotherapeutics may ultimately reduce the risk of CRC development and positively impact CRC outcomes.


Assuntos
Anti-Infecciosos , Bacteriocinas , Neoplasias Colorretais , Microbioma Gastrointestinal , Streptococcus salivarius , Colo , Neoplasias Colorretais/microbiologia , Fusobacterium nucleatum/genética , Humanos , RNA Ribossômico 16S
17.
J Appl Microbiol ; 133(3): 2014-2026, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35818755

RESUMO

AIMS: Bacteriocinogenic lactic acid bacteria (LAB) isolates and Croton heliotropiifolius essential oil (EO) were used to inhibit Staphylococcus aureus subsp. aureus and enhance the antioxidant action in goat coalho cheese (GCC). METHODS AND RESULTS: Lactic acid bacteria isolates were selected for their inhibitory capacity against S. aureus subsp. aureus, safety, existence of bacteriocin-encoding genes, bacteriocinogenic activity, and its antistaphylococcal action. The staphylococcal inhibition capacity of C. heliotropiifolius EO was also verified. Three cheeses were prepared containing S. aureus subsp. aureus (GCC SA), S. aureus subsp. aureus + LAB (GCC SA + LAB), and S. aureus subsp. aureus + EO (GCC SA + EO). Samples were analysed on days 0, 7, 14 and 21. Based on the screening, three LAB isolates were selected and identified as Enterococcus faecium. In GCC, the smallest population of S. aureus subsp. aureus was found until the 17th in the GCC SA + EO and from the 18th in the GCC SA + LAB. Total phenolic content and antioxidant activity increased over time in GCCs. CONCLUSIONS: Autochthonous bacteriocinogenic LAB and C. heliotropiifolius EO are natural resources of the Caatinga, an exclusively Brazilian biome that predominates in the northeast of the country, with the potential to reduce the presence of S. aureus and increase the antioxidant activity in the GCC. SIGNIFICANCE AND IMPACT OF THE STUDY: Goat coalho cheese is a product of cultural importance in northeastern Brazil. The process of obtaining the GCC is manual, and there is a high frequency of S. aureus in the product. Resources of the Caatinga with biofunctional properties can be tested to reduce the risk of staphylococcal toxins, and contribute to the nutritional value of the GCC, maintaining regional characteristics and respecting the local cultural tradition. LAB and C. heliotropiifolius EO contribute to the incorporation of bioactive substances and microbiological quality, generating a value-added GCC with exclusive resources of the Caatinga.


Assuntos
Bacteriocinas , Queijo , Lactobacillales , Óleos Voláteis , Animais , Antioxidantes/farmacologia , Bacteriocinas/farmacologia , Queijo/microbiologia , Cabras , Óleos Voláteis/farmacologia , Staphylococcus aureus
18.
Gene ; 840: 146744, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-35863717

RESUMO

Bacillus licheniformis is a well-known probiotic that can be found in a variety of foods. The strain Bacillus licheniformis MCC 2514 was previously characterized by our group for its bio-physiological capabilities establishing it as a promising probiotic, but information on the genetic evidence for its attributes was lacking. In the current study, whole genome analysis identified the underlying molecular determinants responsible for its probiotic potential. The circular genome of MCC 2514 was 4,230,480 bp with 46.2% GC content, 24 rRNA, and 83 tRNA genes. The pangenome analysis between B. licheniformis MCC 2514 and 12 other B. licheniformis strains revealed a pangenome of 6008 genes and core genome of 3775 genes. Genome mining revealed NRPS and bacteriocins producing gene clusters indicating its biocontrol properties. Several genes encoding carbohydrate degrading enzymes, which aid in proper food degradation in the intestine, were also observed. Stress tolerance, vitamin, and essential amino acids biosynthesis related genes were found, which are important characteristics of a probiotic strain. Additionally, vital genes responsible for gut adhesion and biofilm formation were observed in its genome. The bacterium has been shown to improve the shelf life of idli batter by preventing whey separation, CO2, and odour production while maintaining the pH of 3.96-4.29, especially at cold temperatures. It has significantly reduced coliform contamination at both room and low temperatures, demonstrating its bio-preservative ability, which is also corroborated by the presence of the NRPS and bacteriocin gene clusters in its genome. The present study helped to understand both, the ability of B. licheniformis MCC 2514 to adapt the intestinal gut environment and its probiotic functionality for food preservation.


Assuntos
Bacillus licheniformis , Bacteriocinas , Probióticos , Bacillus licheniformis/genética , Bacillus licheniformis/metabolismo , Bactérias/genética , Bacteriocinas/genética , Bacteriocinas/metabolismo , Genoma Bacteriano
19.
J Biomed Nanotechnol ; 18(4): 1227-1235, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35854440

RESUMO

Bacteriocins are peptides produced by bacteria to inhibit the growth of other prokaryotes. Nisin is a bacteriocin widely used in the food industry and for biomedical applications. However, bacteriocins have some limitations, as they experience mechanisms of resistance, degradation by proteases, and suboptimal intracellular delivery. Combining bacteriocins with nanoscale drug delivery systems (nano-DDS) is an approach that can help overcome these limitations. Among the nano-DDS, solid lipid nanoparticles (SLN) have been described as promising candidates, because of their potential for industrial scale-up and lower toxicity. The objective of this proof-of-concept study was to investigate the use of nisin-loaded SLN (SLN-Nisin) as an antimicrobial and anticancer therapeutic. We show that SLN-Nisin can significantly inhibit the growth of the oral pathogen, Treponema denticola, disrupt oral biofilms, and decrease oral squamous cell carcinoma cell (OSCC) viability compared to free nisin. Further, analysis with scanning electron microscopy (SEM) revealed significant morphological changes in OSCC cells challenged with SLN-Nisin, compared to the empty-nanoparticle or free nisin, indicating that SLN-Nisin likely decreases cell viability by increasing pore formation. This data reveals that nano-DDS are robust tools that can enhance bacteriocin properties.


Assuntos
Antineoplásicos , Bacteriocinas , Carcinoma de Células Escamosas , Neoplasias Bucais , Nanopartículas , Nisina , Antibacterianos/química , Antineoplásicos/farmacologia , Bacteriocinas/química , Bacteriocinas/metabolismo , Bacteriocinas/farmacologia , Biofilmes , Humanos , Lipossomos , Nisina/química , Nisina/metabolismo , Nisina/farmacologia
20.
Molecules ; 27(13)2022 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-35807524

RESUMO

We aimed to evaluate the inhibitory effect and mechanism of plantaricin YKX on S. aureus. The mode of action of plantaricin YKX against the cells of S. aureus indicated that plantaricin YKX was able to cause the leakage of cellular content and damage the structure of the cell membranes. Additionally, plantaricin YKX was also able to inhibit the formation of S. aureus biofilms. As the concentration of plantaricin YKX reached 3/4 MIC, the percentage of biofilm formation inhibition was over 50%. Fluorescent dye labeling combined with fluorescence microscopy confirmed the results. Finally, the effect of plantaricin YKX on the AI-2/LuxS QS system was investigated. Molecular docking predicted that the binding energy of AI-2 and plantaricin YKX was -4.7 kcal/mol and the binding energy of bacteriocin and luxS protein was -183.701 kcal/mol. The expression of the luxS gene increased significantly after being cocultured with plantaricin YKX, suggesting that plantaricin YKX can affect the QS system of S. aureus.


Assuntos
Bacteriocinas , Infecções Estafilocócicas , Staphylococcus aureus , Antibacterianos/química , Bacteriocinas/química , Bacteriocinas/farmacologia , Biofilmes/efeitos dos fármacos , Humanos , Simulação de Acoplamento Molecular , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos
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