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603300.9747Antibacterial Activity of Lactobacillus Strains Isolated from Mongolian Yogurt against Gardnerella vaginalis. Worldwide interest in the use of functional foods containing probiotic bacteria such as Lactobacillus and Bifidobacterium for health promotion and disease prevention has increased significantly. Probiotics have demonstrated beneficial properties including strengthening the body's natural defense system, inhibiting the growth of pathogenic bacteria, and regulating mental activity, but their effects on the human vagina have not been fully elucidated. The primary purpose of our study was to isolate Lactobacillus strains from old yogurt, a traditional dairy product, and investigate their probiotic potential with respect to the human vaginal system. Four Lactobacillus plantarum (L. plantarum) strains, named ZX1, ZX2, ZX27, and ZX69, were isolated from the yogurt samples. Simultaneously, we used a commercial Lactobacillus strain (Lactobacillus delbrueckii DM8909) as a control strain. We tested the antimicrobial activity of Lactobacillus isolates against Escherichia coli and Gardnerella vaginalis by agar spot and well diffusion tests. Then, we tested the antibiotic susceptibility of the 5 strains by using the minimal inhibitory concentration method. We attempted to detect possible bacteriocin genes by PCR sequencing technique. Using a chemically defined medium simulating genital tract secretions, we found that the selected Lactobacillus strains could alter the expression of known virulence genes in Gardnerella vaginalis. Bacteriocins derived from these isolated strains had potent antibacterial activity against G. vaginalis and E. coli, with the most effective activity observed in the case of ZX27. In addition, all strains including the L. delbrueckii DM8909 were positive for the presence of the plantaricin cluster of genes described in L. plantarum C11. The tested stains possessed the pln gene indicating that one of the antibacterial agents was plantaricin. We assume that the production of antimicrobial substances such as bacteriocins induce G. vaginalis to upregulate antimicrobial resistance genes. The new isolated strains have bacteriocin-related genes and can change the antimicrobial resistance gene transcription of G. vaginalis.202032382546
313210.9741Metagenomics reveals differences in the composition of bacterial antimicrobial resistance and antibiotic resistance genes in pasteurized yogurt and probiotic bacteria yogurt from China. Antimicrobial resistance has become a global public health concern, and antibiotic resistance genes (ARG) in food are a research focus. In China, probiotics and pasteurized yogurts are the 2 main types of commercially available yogurt, but the distribution and differences of antibiotic-resistant bacteria and gene types in these products are not well known. This study used a shotgun metagenomic approach to analyze 22 different types of yogurt collected from 9 main yogurt-producing areas in China; each type of yogurt included 8 different batches of samples. The abundance and diversity of bacteria identified in probiotic yogurt were significantly higher than those in pasteurized yogurt, with Acetobacter, Raoultella, and Burkholderia identified as unique and highly abundant genera in probiotic yogurt. Similarly, the abundance of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. was higher than that in pasteurized yogurt. A total of 1,149 ARG subtypes belonging to 16 ARG types were identified, with the highest abundance of rifampicin, multidrug efflux pumps, and quinolone resistance genes detected. Network analysis revealed significant nonrandom co-occurrence relationships between different types and subtypes of ARG in yogurt samples. A total of 44 ARG subtypes in pasteurized yogurt were potentially hosted by 36 bacterial genera, and in probiotic yogurt, 63 ARG were expected to be hosted by 86 bacterial species from 37 genera. These findings indicate potential safety issues in fermented dairy products and emphasize the need for a more hygienic environment when processing probiotic yogurt.202438246555
846320.9738Safety assessment of five candidate probiotic lactobacilli using comparative genome analysis. Micro-organisms belonging to the Lactobacillus genus complex are often used for oral consumption and are generally considered safe but can exhibit pathogenicity in rare and specific cases. Therefore, screening and understanding genetic factors that may contribute to pathogenicity can yield valuable insights regarding probiotic safety. Limosilactobacillus mucosae LM1, Lactiplantibacillus plantarum SK151, Lactiplantibacillus plantarum BS25, Limosilactobacillus fermentum SK152 and Lactobacillus johnsonii PF01 are current probiotics of interest; however, their safety profiles have not been explored. The genome sequences of LM1, SK151, SK152 and PF01 were downloaded from the NCBI GenBank, while that of L. plantarum BS25 was newly sequenced. These genomes were then annotated using the Rapid Annotation using Subsystem Technology tool kit pipeline. Subsequently, a command line blast was performed against the Virulence Factor Database (VFDB) and the Comprehensive Antibiotic Resistance Database (CARD) to identify potential virulence factors and antibiotic resistance (AR) genes. Furthermore, ResFinder was used to detect acquired AR genes. The query against the VFDB identified genes that have a role in bacterial survivability, platelet aggregation, surface adhesion, biofilm formation and immunoregulation; and no acquired AR genes were detected using CARD and ResFinder. The study shows that the query strains exhibit genes identical to those present in pathogenic bacteria with the genes matched primarily having roles related to survival and surface adherence. Our results contribute to the overall strategies that can be employed in pre-clinical safety assessments of potential probiotics. Gene mining using whole-genome data, coupled with experimental validation, can be implemented in future probiotic safety assessment strategies.202438361650
605330.9738Probiotic properties of lactic acid bacteria isolated from water-buffalo mozzarella cheese. This study evaluated the probiotic properties (stability at different pH values and bile salt concentration, auto-aggregation and co-aggregation, survival in the presence of antibiotics and commercial drugs, study of β-galactosidase production, evaluation of the presence of genes encoding MapA and Mub adhesion proteins and EF-Tu elongation factor, and the presence of genes encoding virulence factor) of four LAB strains (Lactobacillus casei SJRP35, Leuconostoc citreum SJRP44, Lactobacillus delbrueckii subsp. bulgaricus SJRP57 and Leuconostoc mesenteroides subsp. mesenteroides SJRP58) which produced antimicrobial substances (antimicrobial peptides). The strains survived the simulated GIT modeled in MRS broth, whole and skim milk. In addition, auto-aggregation and the cell surface hydrophobicity of all strains were high, and various degrees of co-aggregation were observed with indicator strains. All strains presented low resistance to several antibiotics and survived in the presence of commercial drugs. Only the strain SJRP44 did not produce the β-galactosidase enzyme. Moreover, the strain SJRP57 did not show the presence of any genes encoding virulence factors; however, the strain SJRP35 presented vancomycin resistance and adhesion of collagen genes, the strain SJRP44 harbored the ornithine decarboxylase gene and the strain SJRP58 generated positive results for aggregation substance and histidine decarboxylase genes. In conclusion, the strain SJRP57 was considered the best candidate as probiotic cultures for further in vivo studies and functional food products development.201425117002
613740.9737Genomic and phenotypic analyses of Carnobacterium jeotgali strain MS3(T), a lactate-producing candidate biopreservative bacterium isolated from salt-fermented shrimp. Carnobacterium jeotgali strain MS3(T) was isolated from traditionally fermented Korean shrimp produced with bay salt. The bacterium belongs to the family Carnobacteriaceae, produces lactic acid and contains gene clusters involved in the production of lactate, butyrate, aromatic compounds and exopolysaccharides. Carnobacterium jeotgali strain MS3(T) was characterized through extensive comparison of the virulence potential, genomic relatedness and sequence similarities of its genome with the genomes of other Carnobacteria and lactic acid bacteria. In addition, links between predicted functions of genes and phenotypic characteristics, such as antibiotic resistance and lactate and butyrate production, were extensively evaluated. Genomic and phenotypic analyses of strain MS3(T) revealed promising features, including minimal virulence genes and lactate production, which make this bacterium a desirable candidate for exploitation by the fermented food industry.201525868912
72350.9737Ail and PagC-related proteins in the entomopathogenic bacteria of Photorhabdus genus. Among pathogenic Enterobacteriaceae, the proteins of the Ail/OmpX/PagC family form a steadily growing family of outer membrane proteins with diverse biological properties, potentially involved in virulence such as human serum resistance, adhesion and entry into eukaryotic culture cells. We studied the proteins Ail/OmpX/PagC in the bacterial Photorhabdus genus. The Photorhabdus bacteria form symbiotic complexes with nematodes of Heterorhabditis species, associations which are pathogenic to insect larvae. Our phylogenetic analysis indicated that in Photorhabdus asymbiotica and Photorhabdus luminescens only Ail and PagC proteins are encoded. The genomic analysis revealed that the Photorhabdus ail and pagC genes were present in a unique copy, except two ail paralogs from P. luminescens. These genes, referred to as ail1Pl and ail2Pl, probably resulted from a recent tandem duplication. Surprisingly, only ail1Pl expression was directly controlled by PhoPQ and low external Mg2+ conditions. In P. luminescens, the magnesium-sensing two-component regulatory system PhoPQ regulates the outer membrane barrier and is required for pathogenicity against insects. In order to characterize Ail functions in Photorhabdus, we showed that only ail2Pl and pagCPl had the ability, when expressed into Escherichia coli, to confer resistance to complement in human serum. However no effect in resistance to antimicrobial peptides was found. Thus, the role of Ail and PagC proteins in Photorhabdus life cycle is discussed.201425333642
923160.9737CRISPR: new horizons in phage resistance and strain identification. Bacteria have been widely used as starter cultures in the food industry, notably for the fermentation of milk into dairy products such as cheese and yogurt. Lactic acid bacteria used in food manufacturing, such as lactobacilli, lactococci, streptococci, Leuconostoc, pediococci, and bifidobacteria, are selectively formulated based on functional characteristics that provide idiosyncratic flavor and texture attributes, as well as their ability to withstand processing and manufacturing conditions. Unfortunately, given frequent viral exposure in industrial environments, starter culture selection and development rely on defense systems that provide resistance against bacteriophage predation, including restriction-modification, abortive infection, and recently discovered CRISPRs (clustered regularly interspaced short palindromic repeats). CRISPRs, together with CRISPR-associated genes (cas), form the CRISPR/Cas immune system, which provides adaptive immunity against phages and invasive genetic elements. The immunization process is based on the incorporation of short DNA sequences from virulent phages into the CRISPR locus. Subsequently, CRISPR transcripts are processed into small interfering RNAs that guide a multifunctional protein complex to recognize and cleave matching foreign DNA. Hypervariable CRISPR loci provide insights into the phage and host population dynamics, and new avenues for enhanced phage resistance and genetic typing and tagging of industrial strains.201222224556
601970.9737Effects of Lactobacillus pentosus combined with Arthrospira platensis on the growth performance, immune response, and intestinal microbiota of Litopenaeus vannamei. Litopenaeus vannamei is one of the most productive shrimp species in the world. However, shrimp farming is suffering from adverse environmental conditions and disease outbreaks. Typically, Lactobacillus pentosus and Arthrospira platensis are used as substitutes for some antibiotics. In the present study, we assessed the effects of dietary supplements along with living bacteria or cell-free extracts of L. pentosus combined with A. platensis on the growth performance, immune response, intestinal microbiota, and disease resistance of L. vannamei against Vibrio alginolyticus. Shrimp fed L. pentosus live bacteria combined with A. platensis showed the best growth performance and lowest feed conversion rate. The supplementation diet with L. pentosus live bacteria and A. platensis could significantly enhance the trypsin activity in shrimp after the feeding trial. Given the lowest feed conversion rate in shrimp fed L. pentosus live bacteria combined with A. platensis, we reasonably speculated that the decrease in feed conversion rate may be related to the increase in trypsin activity. In addition, dietary cell-free extracts of L. pentosus combined with A. platensis enhanced the expression of immune-related genes after the feeding trial or challenge test. Moreover, results of the bacterial challenge test indicated that the shrimp fed cell-free extracts of L. pentosus combined with A. platensis diet resulted in the highest survival rate, which suggested that cell-free extracts of L. pentosus and A. platensis could improve the disease resistance against V. alginolyticus by up-regulating the expressions of immune-related genes. Dietary L.pentosus or A. platensis, or their combination, reduced the abundance of harmful bacteria, including Proteobacteria in shrimp intestine, which suggested that L. pentosus and A. platensis could improve the growth performance and health of shrimp by regulating the structure of the intestinal microbiota. The findings of this study demonstrated that L. pentosus live bacteria and A. platensis exerted synergistic effects on the growth performance and digestion in shrimp, while cell-free extracts of L. pentosus and A. platensis showed synergistic effects on the immune response and disease resistance of shrimp against V. alginolyticus.202234883257
882980.9737VtaA8 and VtaA9 from Haemophilus parasuis delay phagocytosis by alveolar macrophages. Haemophilus parasuis, a member of the family Pasteurellaceae, is a common inhabitant of the upper respiratory tract of healthy pigs and the etiological agent of Glässer's disease. As other virulent Pasteurellaceae, H. parasuis can prevent phagocytosis, but the bacterial factors involved in this virulence mechanism are not known. In order to identify genes involved in phagocytosis resistance, we constructed a genomic library of the highly virulent reference strain Nagasaki and clones were selected by increased survival after incubation with porcine alveolar macrophages (PAM). Two clones containing two virulent-associated trimeric autotransporter (VtaA) genes, vtaA8 and vtaA9, respectively, were selected by this method. A reduction in the interaction of the two clones with the macrophages was detected by flow cytometry. Monoclonal antibodies were produced and used to demonstrate the presence of these proteins on the bacterial surface of the corresponding clone, and on the H. parasuis phagocytosis-resistant strain PC4-6P. The effect of VtaA8 and VtaA9 in the trafficking of the bacteria through the endocytic pathway was examined by fluorescence microscopy and a delay was detected in the localization of the vtaA8 and vtaA9 clones in acidic compartments. These results are compatible with a partial inhibition of the routing of the bacteria via the degradative phagosome. Finally, antibodies against a common epitope in VtaA8 and VtaA9 were opsonic and promoted phagocytosis of the phagocytosis-resistant strain PC4-6P by PAM. Taken together, these results indicate that VtaA8 and VtaA9 are surface proteins that play a role in phagocytosis resistance of H. parasuis.201222839779
608090.9736Metagenomic Insights into the Taxonomic and Functional Features of Traditional Fermented Milk Products from Russia. Fermented milk products (FMPs) contain probiotics that are live bacteria considered to be beneficial to human health due to the production of various bioactive molecules. In this study, nine artisanal FMPs (kefir, ayran, khurunga, shubat, two cottage cheeses, bryndza, khuruud and suluguni-like cheese) from different regions of Russia were characterized using metagenomics. A metagenomic sequencing of ayran, khurunga, shubat, khuruud and suluguni-like cheese was performed for the first time. The taxonomic profiling of metagenomic reads revealed that Lactococcus species, such as Lc. lactis and Lc. cremoris prevailed in khuruud, bryndza, one sample of cottage cheese and khurunga. The latter one together with suluguni-like cheese microbiome was dominated by bacteria, affiliated to Lactobacillus helveticus (32-35%). In addition, a high proportion of sequences belonging to the genera Lactobacillus, Lactococcus and Streptococcus but not classified at the species level were found in the suluguni-like cheese. Lactobacillus delbrueckii, as well as Streptococcus thermophilus constituted the majority in another cottage cheese, kefir and ayran metagenomes. The microbiome of shubat, produced from camel's milk, was significantly distinctive, and Lentilactobacillus kefiri, Lactobacillus kefiranofaciens and Bifidobacterium mongoliense represented the dominant components (42, 7.4 and 5.6%, respectively). In total, 78 metagenome-assembled genomes with a completeness ≥ 50.2% and a contamination ≤ 8.5% were recovered: 61 genomes were assigned to the Enterococcaceae, Lactobacillaceae and Streptococcaceae families (the Lactobacillales order within Firmicutes), 4 to Bifidobacteriaceae (the Actinobacteriota phylum) and 2 to Acetobacteraceae (the Proteobacteria phylum). A metagenomic analysis revealed numerous genes, from 161 to 1301 in different products, encoding glycoside hydrolases and glycosyltransferases predicted to participate in lactose, alpha-glucans and peptidoglycan hydrolysis as well as exopolysaccharides synthesis. A large number of secondary metabolite biosynthetic gene clusters, such as lanthipeptides, unclassified bacteriocins, nonribosomal peptides and polyketide synthases were also detected. Finally, the genes involved in the synthesis of bioactive compounds like β-lactones, terpenes and furans, nontypical for fermented milk products, were also found. The metagenomes of kefir, ayran and shubat was shown to contain either no or a very low count of antibiotic resistance genes. Altogether, our results show that traditional indigenous fermented products are a promising source of novel probiotic bacteria with beneficial properties for medical and food industries.202338276185
6023100.9736Bile-inducible efflux transporter from Bifidobacterium longum NCC2705, conferring bile resistance. Bifidobacteria are normal inhabitants of the human gut. Some strains of this genus are considered health promoting or probiotic, being included in numerous food products. In order to exert their health benefits, these bacteria must overcome biological barriers, including bile salts, to colonize and survive in specific parts of the intestinal tract. The role of multidrug resistance (MDR) transporters in bile resistance of probiotic bacteria and the effect of bile on probiotic gene expression are not fully understood. In the present study, the effect of subinhibitory concentrations of bile on the expression levels of predicted MDR genes from three different bifidobacterial strains, belonging to Bifidobacterium longum subsp. longum, Bifidobacterium breve, and Bifidobacterium animalis subsp. lactis, was tested. In this way, two putative MDR genes whose expression was induced by bile, BL0920 from B. longum and its homolog, Bbr0838, from B. breve, were identified. The expression of the BL0920 gene in Escherichia coli was shown to confer resistance to bile, likely to be mediated by active efflux from the cells. To the best of our knowledge, this represents the first identified bifidobacterial bile efflux pump whose expression is induced by bile.200919304838
33110.9736Transgenic Silkworms Overexpressing Relish and Expressing Drosomycin Confer Enhanced Immunity to Multiple Pathogens. The sericulture industry faces substantial economic losses due to severe pathogenic infections caused by fungi, viruses, and bacteria. The development of transgenic silkworms against specific pathogens has been shown to enhance disease resistance against a particular infection. A single gene or its products that can confer protection against multiple pathogens is required. In an attempt to develop silkworms with enhanced immunity against multiple pathogens, we generated transgenic silkworm lines with an overexpressed NF-kB transcription factor, Relish 1, under two different promoters. Separately, a potent anti-fungal gene, Drosomycin, was also expressed in transgenic silkworms. Both Relish 1 and Drosomycin transgenic silkworms had single copy genomic integration, and their mRNA expression levels were highly increased after infection with silkworm pathogens. The overexpression of the Relish 1 in transgenic silkworms resulted in the upregulation of several defense-related genes, Cecropin B, Attacin, and Lebocin, and showed enhanced resistance to Nosema bombycis (microsporidian fungus), Nucleopolyhedrovirus (BmNPV), and bacteria. The Drosomycin expressing transgenic silkworms showed elevated resistance to N. bombycis and bacteria. These findings demonstrate the role of Relish 1 in long-lasting protection against multiple pathogens in silkworms. Further, the successful introduction of a foreign gene, Drosomycin, also led to improved disease resistance in silkworms.202235098482
6076120.9735Isolation and identification of mucin-degrading bacteria originated from human faeces and their potential probiotic efficacy according to host-microbiome enterotype. AIM: Mucin-degrading bacteria are known to be beneficial for gut health. We aimed to isolate human-derived mucin-degrading bacteria and identify potential probiotic characteristics and their effects on the bacterial community and short-chain fatty acid (SCFA) production according to three different enterotypes of the host. METHODS AND RESULTS: Bacteria with mucin decomposition ability from human faeces were isolated and identified by 16S rRNA sequencing and MALDI-TOF. Heat resistance, acid resistance, antibiotic resistance, and antibacterial activity were analysed in the selected bacteria. Their adhesion capability to the Caco-2 cell was determined by scanning electron microscopy. Their ability to alter the bacterial community and SCFA production of the isolated bacteria was investigated in three enterotypes. The three isolated strains were Bifidobacterium(Bif.) animalis SPM01 (CP001606.1, 99%), Bif. longum SPM02 (NR_043437.1, 99%), and Limosilactobacillus(L.) reuteri SPM03 (CP000705.1, 99%) deposited in Korean Collection for Type Culture (KCTC-18958P). Among them, Bif. animalis exhibited the highest mucin degrading ability. They exhibited strong resistance to acidic conditions, moderate resistance to heat, and the ability to adhere tightly to Caco-2 cells. Three isolated mucin-degrading bacteria incubation increased Lactobacillus in the faecal bacteria from Bacteroides and Prevotella enterotypes. However, only L. reuteri elevated Lactobacillus in the faecal bacteria from the Ruminococcus enterotype. B. longum and B. animalis increased the α-diversity in the Ruminococcus enterotype, while their incubation with other intestinal types decreased the α-diversity. Bifidobacterium animalis and L. reuteri increased the butyric acid level in faecal bacteria from the Prevotella enterotype, and L. reuteri elevated the acetic acid level in those from the Ruminococcus enterotype. However, the overall SCFA changes were minimal. CONCLUSIONS: The isolated mucin-degrading bacteria act as probiotics and modulate gut microbiota and SCFA production differently according to the host's enterotypes. SIGNIFICANCE AND IMPACT OF STUDY: Probiotics need to be personalized according to the enterotypes in clinical application.202235365862
8799130.9735The membrane-active polyaminoisoprenyl compound NV716 re-sensitizes Pseudomonas aeruginosa to antibiotics and reduces bacterial virulence. Pseudomonas aeruginosa is intrinsically resistant to many antibiotics due to the impermeability of its outer membrane and to the constitutive expression of efflux pumps. Here, we show that the polyaminoisoprenyl compound NV716 at sub-MIC concentrations re-sensitizes P. aeruginosa to abandoned antibiotics by binding to the lipopolysaccharides (LPS) of the outer membrane, permeabilizing this membrane and increasing antibiotic accumulation inside the bacteria. It also prevents selection of resistance to antibiotics and increases their activity against biofilms. No stable resistance could be selected to NV716-itself after serial passages with subinhibitory concentrations, but the transcriptome of the resulting daughter cells shows an upregulation of genes involved in the synthesis of lipid A and LPS, and a downregulation of quorum sensing-related genes. Accordingly, NV716 also reduces motility, virulence factors production, and biofilm formation. NV716 shows a unique and highly promising profile of activity when used alone or in combination with antibiotics against P. aeruginosa, combining in a single molecule anti-virulence and potentiator effects. Additional work is required to more thoroughly understand the various functions of NV716.202236008485
6025140.9735Phenotypic and Genomic Insights into Schleiferilactobacillus harbinensis WU01, a Candidate Probiotic with Broad-Spectrum Antimicrobial Activity Against ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter) Pathogens. The increasing prevalence of multidrug-resistant (MDR) pathogens, particularly ESKAPE bacteria, necessitates alternative antimicrobial strategies. Probiotics, particularly lactic acid bacteria, protect against pathogenic infections. This study aimed to characterize Schleiferilactobacillus harbinensis WU01, isolated from fermented palm sap, and evaluate its probiotic potential and antimicrobial activity. Its probiotic characteristics were assessed based on low-pH and bile tolerance, auto-aggregation, hydrophobicity, and adhesion to Caco-2 cells. Antimicrobial activity against ESKAPE pathogens was evaluated using the agar well diffusion assay. Whole-genome sequencing (WGS) and in silico analysis were performed to identify bacteriocin-related genes, virulence factors, and antibiotic-resistance genes. WU01 exhibited a strong tolerance to gastrointestinal conditions, with high survival rates under acidic and bile-salt environments. S. harbinensis WU01 demonstrated significant auto-aggregation, high hydrophobicity, and strong adhesion to Caco-2 cells. Antimicrobial assays revealed inhibitory activity against MDR ESKAPE pathogens, which correlated with the presence of bacteriocin-related genes, including those homologous to Carnocin_CP52. Molecular dynamics (MDs) simulations confirmed the interaction of Carnocin_CP52 with bacterial membranes, suggesting a mechanism for pathogen disruption. WGS confirmed the absence of virulence and antimicrobial-resistance genes, confirming its safety for probiotic applications. These findings suggest that S. harbinensis WU01 possesses probiotic properties and antimicrobial activity against ESKAPE pathogens. The combined results highlight its potential application in functional foods and therapeutic interventions.202540238333
6052150.9735Safety and technological application of autochthonous Streptococcus thermophilus cultures in the buffalo Mozzarella cheese. Thermophilic and mesophilic lactic acid bacteria (LAB), such as Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus helveticus, and Lactococcus lactis, play a crucial role in the technological and sensory quality of Mozzarella cheese. In this study, the safety (genes encoding virulence factors and antibiotic resistance) and acidifying activity of autochthonous S. thermophilus cultures were evaluated in order to choose the most suitable strain for industrial application. The safe and good acidifying culture was tested in two buffalo Mozzarella cheese batches: Mozzarella cheeses produced with autochthonous culture (SJRP107) and commercial culture (STM5). The cultivable LAB was evaluated by culture-dependent method (plate counting) and the quantification of S. thermophilus cultures (commercial and autochthonous) were evaluated by culture-independent method RealT-qPCR (real-time quantitative polymerase chain reaction). The texture, physicochemical and proteolytic properties of the Mozzarella cheeses were similar for both batches. The nonstarter LAB count was higher during manufacture than in the storage, and the RealT-qPCR indicated the presence of S. thermophilus culture until the end of storage. S. thermophilus SJRP107 presented high potential for safety application in the production of Mozzarella cheese. Furthermore, considering the culture characteristics and their relationship with product quality, further studies could be helpful to determine their effect on the sensory characteristics of the cheese.202031948624
8792160.9735Potential Antagonistic Bacteria against Verticillium dahliae Isolated from Artificially Infested Nursery. As an ecofriendly biocontrol agent, antagonistic bacteria are a crucial class of highly efficient fungicides in the field against Verticillium dahliae, the most virulent pathogen for cotton and other crops. Toward identifying urgently needed bacterial candidates, we screened bacteria isolated from the cotton rhizosphere soil for antagonisitic activity against V. dahliae in an artificially infested nursery. In preliminary tests of antagonistic candidates to characterize the mechanism of action of on culture medium, 88 strains that mainly belonged to Bacillus strongly inhibited the colony diameter of V. dahliae, with inhibiting efficacy up to 50% in 9 strains. Among the most-effective bacterial strains, Bacillus sp. ABLF-18, and ABLF-50 and Paenibacillus sp. ABLF-90 significantly reduced the disease index and fungal biomass of cotton to 40-70% that of the control. In further tests to elucidate the biocontrol mechanism (s), the strains secreted extracellular enzymes cellulase, glucanase, and protease, which can degrade the mycelium, and antimicrobial lipopeptides such as surfactin and iturin homologues. The expression of PAL, MAPK and PR10, genes related to disease resistance, was also elicited in cotton plants. Our results clearly show that three candidate bacterial strains can enhance cotton defense responses against V. dahliae; the secretion of fungal cell-wall-degrading enzymes, synthesis of nonribosomal antimicrobial peptides and induction of systemic resistance shows that the strains have great potential as biocontrol fungicides.202134944096
336170.9734Genetically engineered termite gut bacteria (Enterobacter cloacae) deliver and spread foreign genes in termite colonies. Indigenous gut bacteria of the Formosan subterranean termite (Coptotermes formosanus Shiraki, Isoptera: Rhinotermitidae) were used as shuttle systems to deliver, express and spread foreign genes in termite colonies. The gut bacterium Enterobacter cloacae was transformed with a recombinant plasmid (pEGFP) containing genes encoding ampicillin resistance and green fluorescent protein (GFP). In laboratory experiments, termite workers and soldiers from three colonies were fed with filter paper inoculated with transformed bacteria. Transformed bacteria were detected in termite guts by growing the entire gut flora under selective conditions and checking the cultures visually for fluorescence. We demonstrated that (1) transformed bacteria were ingested within a few hours and the GFP gene was expressed in the termite gut; (2) transformed bacteria established a persistent population in the termite gut for up to 11 weeks; (3) transformed bacteria were efficiently transferred throughout a laboratory colony, even when the donor (termites initially fed with transformed bacteria) to recipient (not fed) ratio was low; (4) transformed E. cloacae were transferred into soil; however, they did not accumulate over time and the GFP plasmid was not transferred to other soil bacteria. In the future, transgenic bacteria may be used to shuttle detrimental genes into termite colonies for improved pest control.200515742168
4811180.9734Lantibiotic-producing bacteria impact microbiome resilience and colonization resistance. A subset of commensal bacterial strains secrete bacteriocins, such as lantibiotics, to establish and protect their niche in the gut. Because the antimicrobial spectrum of lantibiotics includes opportunistic pathogens, such as vancomycin-resistant Enterococcus faecium (VRE), they may provide an approach to reduce antibiotic-resistant infections. The impact of lantibiotic-producing bacteria on the complex microbial populations constituting the microbiome, however, remains poorly defined. We find that genes encoding lanthipeptides, including lantibiotics, are commonly present in the microbiomes of healthy humans and in dysbiotic microbiomes of hospitalized patients. In fecal samples collected from hospitalized patients, bacterial species encoding lantibiotic genes are present in greater abundance than lantibiotic-deficient strains of the same species. We demonstrate that the lantibiotic-producing bacterium, Blautia pseudococcoides SCSK, prevents intestinal recolonization of mice by a wide range of commensal species following antibiotic-induced dysbiosis and markedly reduces fecal concentrations of microbiota-derived metabolites associated with mucosal immune defenses. Lantibiotic-mediated dysbiosis results in sustained loss of colonization resistance against Klebsiella pneumoniae and Clostrioides difficile infection. Our findings reveal the potential impact of lantibiotic-producing bacterial species on microbiome resilience and susceptibility to infection following antibiotic treatment.202540654602
9025190.9734BING, a novel antimicrobial peptide isolated from Japanese medaka plasma, targets bacterial envelope stress response by suppressing cpxR expression. Antimicrobial peptides (AMPs) have emerged as a promising alternative to small molecule antibiotics. Although AMPs have previously been isolated in many organisms, efforts on the systematic identification of AMPs in fish have been lagging. Here, we collected peptides from the plasma of medaka (Oryzias latipes) fish. By using mass spectrometry, 6399 unique sequences were identified from the isolated peptides, among which 430 peptides were bioinformatically predicted to be potential AMPs. One of them, a thermostable 13-residue peptide named BING, shows a broad-spectrum toxicity against pathogenic bacteria including drug-resistant strains, at concentrations that presented relatively low toxicity to mammalian cell lines and medaka. Proteomic analysis indicated that BING treatment induced a deregulation of periplasmic peptidyl-prolyl isomerases in gram-negative bacteria. We observed that BING reduced the RNA level of cpxR, an upstream regulator of envelope stress responses. cpxR is known to play a crucial role in the development of antimicrobial resistance, including the regulation of genes involved in drug efflux. BING downregulated the expression of efflux pump components mexB, mexY and oprM in P. aeruginosa and significantly synergised the toxicity of antibiotics towards these bacteria. In addition, exposure to sublethal doses of BING delayed the development of antibiotic resistance. To our knowledge, BING is the first AMP shown to suppress cpxR expression in Gram-negative bacteria. This discovery highlights the cpxR pathway as a potential antimicrobial target.202134108601