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605300.9510Probiotic 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
605210.9488Safety 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
601520.9468Integrative genome analysis of bacteriocin-producing Lactiplantibacillus pentosus LNP1-39 and its synbiotic role in suppressing food-borne pathogens. Lactic acid bacteria were isolated from traditional Thai-fermented foods. Among these, the strain LNP1-39, closely related to Lactiplantibacillus pentosus, was selected for further study because of its non-pathogenic profile. The bacteriocins produced by L. pentosus LNP1-39 were proteinaceous substances that exhibited strong antimicrobial activity across a wide pH range (pH 2-11; 6400-2400 AU/mL) and thermal stability at 100 °C for 40 min (400 AU/mL). These bacteriocins showed a narrow antimicrobial spectrum, effectively targeting Gram-positive pathogens, such as Kocuria rhizophila MIII, Enterococcus faecalis JCM 5803( T), and Listeria monocytogenes ATCC 19115. Comprehensive safety assessments, including whole-genome analysis and in vitro tests, confirmed a low risk of antibiotic resistance and the absence of virulence factors. Strain LNP1-39 was confirmed to be closely related to L. pentosus DSM 20314( T) via digital DNA‒DNA hybridization (dDDH; 75.4%), with average nucleotide identity (ANI) at 96.56% ANIb and 97.22% ANIm values. Additionally, LNP1-39 produces pediocin with notable similarity (76.29% identity to pediocin) and presents low risks for antibiotic-resistance genes or transfer genes while providing antioxidant properties. Strain LNP1-39 survived harsh gastrointestinal tract conditions and exhibited a favorable prebiotic index and positive prebiotic activity score when paired with polydextrose or isomalto-oligosaccharide. These findings support L. pentosus LNP1-39 as potential bacteriocin-producing lactic acid bacteria for further application in food preservation and pathogen control or as a synbiotic.202540622670
604930.9454Probiotic Properties and Antioxidant Activity In Vitro of Lactic Acid Bacteria. The properties of probiotics such as lactic acid bacteria (LAB) have been widely studied over the last decades. In the present study, four different LAB species, namely Lactobacillus gasseri ATCC 33323, Lacticaseibacillus rhamnosus GG ATCC 53103, Levilactobacillus brevis ATCC 8287, and Lactiplantibacillus plantarum ATCC 14917, were investigated in order to determine their ability to survive in the human gut. They were evaluated based on their tolerance to acids, resistance to simulated gastrointestinal conditions, antibiotic resistance, and the identification of genes encoding bacteriocin production. All four tested strains demonstrated high resistance to simulated gastric juice after 3 h, and the viable counts revealed declines in cell concentrations of less than 1 log cycle. L. plantarum showed the highest level of survival in the human gut, with counts of 7.09 log CFU/mL. For the species L. rhamnosus and L. brevis, the values were 6.97 and 6.52, respectively. L. gasseri, after 12 h, showed a 3.96 log cycle drop in viable counts. None of the evaluated strains inhibited resistance to ampicillin, gentamicin, kanamycin, streptomycin, erythromycin, clindamycin, tetracycline, or chloramphenicol. With regard to bacteriocin genes, the Pediocin PA gene was identified in Lactiplantibacillus plantarum ATCC 14917, Lacticaseibacillus rhamnosus GG ATCC 53103, and Lactobacillus gasseri ATCC 33323. The PlnEF gene was detected in Lactiplantibacillus plantarum ATCC 14917 and Lacticaseibacillus rhamnosus GG ATCC 53103. The Brevicin 174A and PlnA genes were not detected in any bacteria. Moreover, the potential antioxidant activity of LAB's metabolites was evaluated. At the same time, the possible antioxidant activity of metabolites of LAB was first tested using the free radical DDPH(•) (a, a-Diphenyl-β-Picrylhydrazyl) and then evaluated with regard to their radical scavenging activity and inhibition against peroxyl radical induced DNA scission. All strains showed antioxidant activity; however, the best antioxidant activity was achieved by L. brevis (94.47%) and L. gasseri (91.29%) at 210 min. This study provides a comprehensive approach to the action of these LAB and their use in the food industry.202337317238
10440.9451Bile Salt Hydrolases with Extended Substrate Specificity Confer a High Level of Resistance to Bile Toxicity on Atopobiaceae Bacteria. The bile resistance of intestinal bacteria is among the key factors responsible for their successful colonization of and survival in the mammalian gastrointestinal tract. In this study, we demonstrated that lactate-producing Atopobiaceae bacteria (Leptogranulimonas caecicola TOC12(T) and Granulimonas faecalis OPF53(T)) isolated from mouse intestine showed high resistance to mammalian bile extracts, due to significant bile salt hydrolase (BSH) activity. We further succeeded in isolating BSH proteins (designated LcBSH and GfBSH) from L. caecicola TOC12(T) and G. faecalis OPF53(T), respectively, and characterized their enzymatic features. Interestingly, recombinant LcBSH and GfBSH proteins exhibited BSH activity against 12 conjugated bile salts, indicating that LcBSH and GfBSH have much broader substrate specificity than the previously identified BSHs from lactic acid bacteria, which are generally known to hydrolyze six bile salt isomers. Phylogenetic analysis showed that LcBSH and GfBSH had no affinities with any known BSH subgroup and constituted a new BSH subgroup in the phylogeny. In summary, we discovered functional BSHs with broad substrate specificity from Atopobiaceae bacteria and demonstrated that these BSH enzymes confer bile resistance to L. caecicola TOC12(T) and G. faecalis OPF53(T).202236142891
602650.9443Probiotic Characteristics and Whole Genome Analysis of Lactiplantibacillus plantarum PM8 from Giant Panda (Ailuropoda melanoleuca) Milk. Milk is a rich source of probiotics, particularly lactic acid bacteria (LAB), which have been shown to promote gut health, support the immune system, enhance digestion, and prevent pathogen colonization. This study aimed to isolate and identify LAB strains from giant panda (Ailuropoda melanoleuca) milk, evaluate their probiotic properties, and analyze the genomic characteristics of a promising strain. Thirteen LAB strains were isolated from 12 samples of giant panda milk. Among all LAB strains, Lactiplantibacillus plantarum PM8 (PM8) demonstrated probiotic properties and safety features. It exhibited strong growth performance, high antipathogenic activity against four pathogens, and strong survival rates under simulated gastrointestinal conditions. PM8 also showed excellent adhesion capabilities to Caco-2 cells. Additionally, safety assessment revealed no hemolysin production and minimal antibiotic resistance, making it a promising candidate for probiotic applications. The genome of PM8 consists of 3,227,035 bp with a GC content of 44.60% and contains 3171 coding sequences, including 113 carbohydrate-active enzyme genes and genes related to exopolysaccharides synthesis, vitamin B biosynthesis, adhesion, antioxidant activity, and bile salt hydrolysis. Notably, it contains genes involved in nonribosomally synthesized secondary metabolite and bacteriocin production. The genomic safety analysis confirmed that PM8 lacks the capacity to transmit bacterial antimicrobial resistance and is non-pathogenic to both humans and animals. These findings suggest that PM8 holds considerable potential for enhancing gut health and supporting the development of safe probiotic products.202539900880
608060.9442Metagenomic 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
602870.9442Isolation, Characterization, and Comparative Genomics of the Novel Potential Probiotics from Canine Feces. Lactic acid bacteria (LAB) are commonly used as probiotics; however, not all LAB strains have the same beneficial effects. To successfully use LAB as probiotics in canines, LAB species should originate from the canine intestinal tract as they display host specificity. The objective of this study was to investigate the phenotypic and genomic traits of potential probiotic LAB isolated from canine fecal samples. Twenty LAB samples were evaluated for their potential probiotic characteristics including resistance to low pH, bile salts, hydrophobicity, auto-aggregation, co-aggregation, adhesion to epithelia or mucosa, and production of inhibitory compounds. Additionally, we evaluated their safety and other beneficial effects on canine health, such as DPPH free radical scavenging, and β-galactosidase. Four strains demonstrated potential probiotic characteristics and were selected: Enterococcus hirae Pom4, Limosilactobacillus fermentum Pom5, Pediococcus pentosaceus Chi8, and Ligilactobacillus animalis FB2. Safety evaluations showed that all strains lacked hemolytic activity, could not produce biogenic amines, and did not carry any pathogenic genes. In addition, L. fermentum Pom5 and P. pentosaceus Chi8 displayed susceptibility to all antibiotics and concordant with the absence of antibiotic resistance genes. Based on their phenotypic and genomic characteristics, L. fermentum Pom5 and P. pentosaceus Chi8 were identified as potential probiotic candidates for canines.202337484003
601080.9441The role of two families of bacterial enzymes in putrescine synthesis from agmatine via agmatine deiminase. Putrescine, one of the main biogenic amines associated to microbial food spoilage, can be formed by bacteria from arginine via ornithine decarboxylase (ODC), or from agmatine via agmatine deiminase (AgDI). This study aims to correlate putrescine production from agmatine to the pathway involving N-carbamoylputrescine formation via AdDI (the aguA product) and N-carbamoylputrescine amidohydrolase (the aguB product), or putrescine carbamoyltransferase (the ptcA product) in bacteria. PCR methods were developed to detect the two genes involved in putrescine production from agmatine. Putrescine production from agmatine could be linked to the aguA and ptcA genes in Lactobacillus hilgardii X1B, Enterococcus faecalis ATCC 11700, and Bacillus cereus ATCC 14579. By contrast Lactobacillus sakei 23K was unable to produce putrescine, and although a fragment of DNA corresponding to the gene aguA was amplified, no amplification was observed for the ptcA gene. Pseudomonas aeruginosa PAO1 produces putrescine and is reported to harbour aguA and aguB genes, responsible for agmatine deiminase and N-carbamoylputrescine amidohydrolase activities. The enzyme from P. aeruginosa PAO1 that converts N-carbamoylputrescine to putrescine (the aguB product) is different from other microorganisms studied (the ptcA product). Therefore, the aguB gene from P. aeruginosa PAO1 could not be amplified with ptcA-specific primers. The aguB and ptcA genes have frequently been erroneously annotated in the past, as in fact these two enzymes are neither homologous nor analogous. Furthermore, the aguA, aguB and ptcA sequences available from GenBank were subjected to phylogenetic analysis, revealing that gram-positive bacteria harboured ptcA, whereas gram-negative bacteria harbour aguB. This paper also discusses the role of the agmatine deiminase system (AgDS) in acid stress resistance.201021404211
33290.9432Analysis and Reconstitution of the Menaquinone Biosynthesis Pathway in Lactiplantibacillus plantarum and Lentilactibacillus buchneri. In Lactococcus lactis and some other lactic acid bacteria, respiratory metabolism has been reported upon supplementation with only heme, leading to enhanced biomass formation, reduced acidification, resistance to oxygen, and improved long-term storage. Genes encoding a complete respiratory chain with all components were found in genomes of L. lactis and Leuconostoc mesenteroides, but menaquinone biosynthesis was found to be incomplete in Lactobacillaceae (except L. mesenteroides). Lactiplantibacillus plantarum has only two genes (menA, menG) encoding enzymes in the biosynthetic pathway (out of eight), and Lentilactobacillus buchneri has only four (menA, menB, menE, and menG). We constructed knock-out strains of L. lactis defective in menA, menB, menE, and menG (encoding the last steps in the pathway) and complemented these by expression of the extant genes from Lactipl. plantarum and Lent. buchneri to verify their functionality. Three of the Lactipl. plantarum biosynthesis genes, lpmenA1, lpmenG1, and lpmenG2, as well as lbmenB and lbmenG from Lent. buchneri, reconstituted menaquinone production and respiratory growth in the deficient L. lactis strains when supplemented with heme. We then reconstituted the incomplete menaquinone biosynthesis pathway in Lactipl. plantarum by expressing six genes from L. lactis homologous to the missing genes in a synthetic operon with two inducible promoters. Higher biomass formation was observed in Lactipl. plantarum carrying this operon, with an OD(600) increase from 3.0 to 5.0 upon induction.202134361912
8731100.9431Isolation of Potato Endophytes and Screening of Chaetomium globosum Antimicrobial Genes. Antimicrobial peptides (AMPs) have natural antibacterial activities that pathogens find difficult to overcome. As a result of this occurrence, AMPs can act as an important substitute against the microbial resistance. In this study, we used plate confrontation tests to screen out 20 potential endophytes from potato tubers. Among them, endophyte F5 was found to significantly inhibit the growth of five different pathogenic fungi. Following that, phylogenetic analysis revealed that the internal transcribed spacer (ITS) sequences were 99% identical to Chaetomium globosum corresponding sequences. Thereafter, the Bacillus subtilis expression system was used to create a C. globosum cDNA library in order to isolate the resistance genes. Using this approach, the resistance gene screening technology in the indicator bacteria built-in library was used to identify two antimicrobial peptides, CgR2150 and CgR3101, with broad-spectrum antibacterial activities. Furthermore, the results showed that CgR2150 and CgR3101 have excellent UV, thermal, and enzyme stabilities. Also, these two peptides can significantly inhibit the growth of various bacteria (Xanthomonas oryzae pv. oryzae, Xanthomonas oryzae pv. oryzicola, Clavibacter michiganensis, and Clavibacter fangii) and fungi (Fusarium graminearum, Rhizoctonia solani, and Botrytis cinerea). Scanning electron microscopy (SEM) observations revealed that CgR2150 and CgR3101 peptides act against bacteria by disrupting bacterial cell membranes. Moreover, hemolytic activity assay showed that neither of the two peptides exhibited significant hemolytic activity. To conclude, the antimicrobial peptides CgR2150 and CgR3101 are promising in the development of a new antibacterial agent and for application in plant production.202235563004
8742110.9431Effect of Bacteria and Bacterial Constituents on Recovery and Resistance of Tulane Virus. Noroviruses encounter numerous and diverse bacterial populations in the host and environment, but the impact of bacteria on norovirus transmission, infection, detection, and inactivation are not well understood. Tulane virus (TV), a human norovirus surrogate, was exposed to viable bacteria, bacterial metabolic products, and bacterial cell constituents and was evaluated for impact on viral recovery, propagation, and inactivation resistance, respectively. TV was incubated with common soil, intestinal, skin, and phyllosphere bacteria, and unbound viruses were recovered by centrifugation and filtration. TV recovery from various bacterial suspensions was not impeded, which suggests a lack of direct, stable binding between viruses and bacteria. The cell-free supernatant (CFS) of Bifidobacterium bifidum 35914, a bacterium that produces glycan-modifying enzymes, was evaluated for effect on the propagation of TV in LLC-MK2 cells. CFS did not limit TV propagation relative to TV absent of CFS. The impact of Escherichia coli O111:B4 lipopolysaccharide (LPS) and Bacillus subtilis peptidoglycan (PEP) on TV thermal and chlorine inactivation resistance was evaluated. PEP increased TV thermal and chlorine inactivation resistance compared with control TV in phosphate-buffered saline (PBS). TV suspended in PBS and LPS was reduced by more than 3.7 log at 60°C, whereas in PEP, TV reduction was approximately 2 log. Chlorine treatment (200 ppm) rendered TV undetectable (>3-log reduction) in PBS and LPS; however, TV was still detected in PEP, reduced by 2.9 log. Virus inactivation studies and food processing practices should account for potential impact of bacteria on viral resistance.202032221571
6019120.9426Effects 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
6056130.9422Virulence, antibiotic resistance and biogenic amines of bacteriocinogenic lactococci and enterococci isolated from goat milk. The present study aimed to investigate the virulence, antibiotic resistance and biogenic amine production in bacteriocinogenic lactococci and enterococci isolated from goat milk in order to evaluate their safety. Twenty-nine bacteriocinogenic lactic acid bacteria (LAB: 11 Lactococcus spp., and 18 Enterococcus spp.) isolated from raw goat milk were selected and subjected to PCR to identify gelE, cylA, hyl, asa1, esp, efaA, ace, vanA, vanB, hdc1, hdc2, tdc and odc genes. The expression of virulence factors (gelatinase, hemolysis, lipase, DNAse, tyramine, histamine, putrescine) in different incubation temperatures was assessed by phenotypic methods, as well as the resistance to vancomycin, gentamicin, chloramphenicol, ampicillin and rifampicin (using Etest®). The tested isolates presented distinct combinations of virulence related genes, but not necessarily the expression of such factors. The relevance of identifying virulence-related genes in bacteriocinogenic LAB was highlighted, demanding for care in their usage as starter cultures or biopreservatives due to the possibility of horizontal gene transfer to other bacteria in food systems.201424960293
6357140.9419Cloning and expression of the pediocin operon in Streptococcus thermophilus and other lactic fermentation bacteria. Production of pediocin in Pediococcus acidilactici is associated with pMBR1.0, which encodes prepediocin, a pediocin immunity protein, and two proteins involved in secretion and precursor processing. These four genes are organized as an operon under control of a single promoter. We have constructed shuttle vectors that contain all four structural genes, the chromosomal promoter ST(P2201) from Streptococcus thermophilus, and repA from the 2-kbp S. thermophilus plasmid pER8. The recombinant plasmid, pPC318, expressed and secreted active pediocin in Escherichia coli. Streptococcus thermophilus, Lactococcus lactis subsp. lactis, and Enterococcus faecalis were electrotransformed with pPC418, a modified vector fitted with an erythromycin resistance tracking gene. Pediocin was produced and secreted in each of the lactic acid bacteria, and production was stable for up to ten passages. The expression of pediocin in dairy fermentation microbes has important implications for bacteriocins as food preservatives in dairy products.199910489440
6016150.9418Investigating human-derived lactic acid bacteria for alcohol resistance. BACKGROUND: Excessive alcohol consumption has been consistently linked to serious adverse health effects, particularly affecting the liver. One natural defense against the detrimental impacts of alcohol is provided by alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH), which detoxify harmful alcohol metabolites. Recent studies have shown that certain probiotic strains, notably Lactobacillus spp., possess alcohol resistance and can produce these critical enzymes. Incorporating these probiotics into alcoholic beverages represents a pioneering approach that can potentially mitigate the negative health effects of alcohol while meeting evolving consumer preferences for functional and health-centric products. RESULTS: Five lactic acid bacteria (LAB) isolates were identified: Lactobacillus paracasei Alc1, Lacticaseibacillus rhamnosus AA, Pediococcus acidilactici Alc3, Lactobacillus paracasei Alc4, and Pediococcus acidilactici Alc5. Assessment of their alcohol tolerance, safety, adhesion ability, and immunomodulatory effects identified L. rhamnosus AA as the most promising alcohol-tolerant probiotic strain. This strain also showed high production of ADH and ALDH. Whole genome sequencing analysis revealed that the L. rhamnosus AA genome contained both the adh (encoding for ADH) and the adhE (encoding for ALDH) genes. CONCLUSIONS: L. rhamnosus AA, a novel probiotic candidate, showed notable alcohol resistance and the capability to produce enzymes essential for alcohol metabolism. This strain is a highly promising candidate for integration into commercial alcoholic beverages upon completion of comprehensive safety and functionality evaluations.202438659044
6043160.9418Histamine and cholesterol lowering abilities of lactic acid bacteria isolated from artisanal Pico cheese. AIMS: This study was designed to select lactic acid bacteria with histamine- and cholesterol-reducing abilities to be used as potential probiotics. METHODS AND RESULTS: Thirty strains of lactic acid bacteria isolated from an artisanal raw milk cheese were screened for their abilities to degrade histamine, reduce cholesterol and hydrolyse bile salts. Strains were also screened for safety and probiotic traits, such as resistance to gastrointestinal conditions, adhesion to Caco-2 cells, resistance to antibiotics and presence of virulence genes. Two Lactobacillus paracasei strains presented high cholesterol- and histamine-lowering abilities, tested negative for the presence of virulence genes and showed susceptibility to most important antibiotics. These strains were also shown to possess desirable in vitro probiotic properties, revealed by tolerance to gastrointestinal conditions and high adhesion to intestinal cells. CONCLUSIONS: Among the screened strains, Lb. paracasei L3C21M6 revealed the best cholesterol and histamine reducing abilities together with desirable probiotic and safety features to be used in food applications. SIGNIFICANCE AND IMPACT OF THE STUDY: The strain L3C21M6 is a good candidate for use as a probiotic with histamine-degrading activity and cholesterol lowering effect. In addition, this strain could be use in dairy foods to prevent histamine food poisoning.202032500572
8642170.9416Dynamics of Thioalkalivibrio species in a co-culture under selective pressure of ampicillin. Haloalkaliphilic chemolithoautotrophic sulfur-oxidizing bacteria belonging to the genus Thioalkalivibrio are highly abundant in microbial communities found in soda lakes and dominant in full-scale bioreactors removing sulfide from industrial waste gases. Despite certain soda lakes being remote and unaffected by anthropogenic activities, haloalkaliphilic microorganisms, including Thioalkalivibrio strains, possess various antibiotic resistance genes. In this study, we investigated the impact of the antibiotic ampicillin on a co-culture of two Thioalkalivibrio species, Tv. thiocyanoxidans ARh2(T) and Tv. versutus AL2(T), both experimentally and through in silico analysis of antibiotic resistance. Cell growth dynamics were monitored over time at increasing ampicillin concentrations using rep- and qPCR. Within ten days after the addition of ampicillin, the co-culture transitioned from a Tv. thiocyanoxidans ARh2(T)-dominated to a stable Tv. versutus AL2(T)-dominated culture. This shift was attributed to Tv. versutus AL2(T) displaying a lower susceptibility to ampicillin, making it more competitive. These results emphasize the potential implications of antibiotic pressure on microbial communities, where a resistant species can outcompete a stable co-culture. This study presents the first evidence of such dynamics in haloalkaliphilic chemolithoautotrophs. By understanding the antibiotic resistance and the competitive dynamics of haloalkaliphilic bacteria like Thioalkalivibrio, we can gain insights into their behaviour and stress response.202338077120
6035180.9416Developing Gut-Healthy Strains for Pets: Probiotic Potential and Genomic Insights of Canine-Derived Lactobacillus acidophilus GLA09. Probiotics are widely used to improve pet health and welfare due to their significant biological activity and health benefits. Lactobacillus acidophilus GLA09 was derived from the intestinal tract of healthy beagles. The safety and suitability evaluation of GLA09 was completed through a combination of whole genome sequence and phenotypic analyses, including tests for the inhibition of harmful bacteria, acid resistance, bile salt tolerance, adhesion, and amine-producing substance content. The findings revealed that GLA09 has good gastrointestinal tolerance, inhibits the growth of pathogenic bacteria, and does not produce toxic biogenic amines. The genome of GLA09 comprises one chromosome and one plasmid, with a genome size of 2.10 M and a Guanine + Cytosine content of 38.71%. It encodes a total of 2208 genes, including 10 prophages, and 1 CRISPR sequence. Moreover, 56 carbohydrate-encoding genes were identified in the CAZy database, along with 11 genes for cold and heat stress tolerance, 5 genes for bile salt tolerance, 12 genes for acid tolerance, and 14 predicted antioxidant genes. Furthermore, GLA09 has one lincosamide resistance gene, but there is no risk of transfer. GLA09 harbors a cluster of Helveticin J and Enterolysin A genes linked to antimicrobial activity. Genomic analysis validated the probiotic attributes of GLA09, indicating its potential utility as a significant probiotic in the pet food industry. In summary, L. acidophilus GLA09 has the potential to be used as a probiotic in pet food and can effectively combat intestinal health in pets.202540005717
6038190.9415Genomic Comparison of Lactobacillus helveticus Strains Highlights Probiotic Potential. Lactobacillus helveticus belongs to the large group of lactic acid bacteria (LAB), which are the major players in the fermentation of a wide range of foods. LAB are also present in the human gut, which has often been exploited as a reservoir of potential novel probiotic strains, but several parameters need to be assessed before establishing their safety and potential use for human consumption. In the present study, six L. helveticus strains isolated from natural whey cultures were analyzed for their phenotype and genotype in exopolysaccharide (EPS) production, low pH and bile salt tolerance, bile salt hydrolase (BSH) activity, and antibiotic resistance profile. In addition, a comparative genomic investigation was performed between the six newly sequenced strains and the 51 publicly available genomes of L. helveticus to define the pangenome structure. The results indicate that the newly sequenced strain UC1267 and the deposited strain DSM 20075 can be considered good candidates for gut-adapted strains due to their ability to survive in the presence of 0.2% glycocholic acid (GCA) and 1% taurocholic and taurodeoxycholic acid (TDCA). Moreover, these strains had the highest bile salt deconjugation activity among the tested L. helveticus strains. Considering the safety profile, none of these strains presented antibiotic resistance phenotypically and/or at the genome level. The pangenome analysis revealed genes specific to the new isolates, such as enzymes related to folate biosynthesis in strains UC1266 and UC1267 and an integrated phage in strain UC1035. Finally, the presence of maltose-degrading enzymes and multiple copies of 6-phospho-β-glucosidase genes in our strains indicates the capability to metabolize sugars other than lactose, which is related solely to dairy niches.201931293536