Fecal microbiota profiles of growing pigs and their relation to growth performance.

The early gut microbiota composition is fundamentally important for piglet health, affecting long-term microbiome development and immunity. In this study, the gut microbiota of postparturient dams was compared with that of their offspring in three Finnish pig farms at three growth phases. The differences in fecal microbiota of three study development groups (Good, Poorly, and PrematureDeath) were analyzed at birth (initial exposure phase), weaning (transitional phase), and before slaughter (stable phase). Dam Lactobacillaceae abundance was lower than in piglets at birth. Limosilactobacillus reuteri and Lactobacillus amylovorus were dominantly expressed in dams and their offspring. Altogether 17 piglets (68%) were identified with Lactobacillaceae at the initial exposure phase, divided unevenly among the development groups: 85% of Good, 37.5% of Poorly, and 75% of PrematureDeath pigs. The development group Good was identified with the highest microbial diversity, whereas the development group PrematureDeath had the lowest diversity. After weaning, the abundance and versatility of Lactobacillaceae in piglets diminished, shifting towards the microbiome of the dam. In conclusion, the fecal microbiota of pigs tends to develop towards a similar alpha and beta diversity despite development group and rearing environment.

Mechanism Explanation on Improved Cognitive Ability of D-Gal Inducing Aged Mice Model by Lactiplantibacillus plantarum MWFLp-182 via the Microbiota-Gut-Brain Axis.

Gut microbiota can influence cognitive ability via the gut-brain axis. Lactiplantibacillus plantarum MWFLp-182 (L. plantarum MWFLp-182) was obtained from feces of long-living individuals and could exert marked antioxidant ability. Interestingly, this strain reduced the D-galactose-induced impaired cognitive ability in BALB/c mice. To comprehensively elucidate the underlying mechanism, we evaluated the colonization, antioxidant, and anti-inflammatory activities of L. plantarum MWFLp-182, along with the expression of potential genes associated with cognitive ability influenced and gut microbiota. L. plantarum MWFLp-182 enhanced the expression of anti-inflammatory cytokines, reduced the expression of proinflammatory cytokines, and increased tight junction protein expression in the colon. Moreover, L. plantarum MWFLp-182 could modify the gut microbiota. Notably, treatment with L. plantarum MWFLp-182 upregulated the expression of postsynaptic density protein-95, nuclear factor erythroid 2-related factor, nerve growth factor, superoxide dismutase, and brain-derived neurotrophic factor/neuronal nuclei, while downregulating the expression of bcl-2-associated X and malondialdehyde in the hippocampus and upregulating short-chain fatty acids against D-galactose-induced mouse brain deficits. Accordingly, L. plantarum MWFLp-182 could improve cognitive ability in a D-galactose-inducing mouse model.

Exploration adhesion properties of Liquorilactobacillus and Lentilactobacillus isolated from two different sources of tepache kefir grains.

Due to the distinctive characteristics of probiotics, it is essential to pinpoint strains originating from diverse sources that prove efficacious in addressing a range of pathologies linked to dysfunction of the intestinal barrier. Nine strains of lactic acid bacteria were isolated from two different sources of tepache kefir grains (KAS2, KAS3, KAS4, KAS7, KAL4, KBS2, KBS3, KBL1 and KBL3), and were categorized to the genus Lacticaseibacillus, Liquorilactobacillus, and Lentilactobacillus by 16S rRNA gene. Kinetic behaviors of these strains were evaluated in MRS medium, and their probiotic potential was performed: resistance to low pH, tolerance to pepsin, pancreatin, bile salts, antibiotic resistance, hemolytic activity, and adhesion ability. KAS7 strain presented a higher growth rate (0.50 h-1) compared with KAS2 strain, who presented a lower growth rate (0.29 h-1). KBS2 strain was the only strain that survived the in vitro stomach simulation conditions (29.3%). Strain KBL1 demonstrated significantly higher viability (90.6%) in the in vitro intestine simulation conditions. Strain KAS2 demonstrated strong hydrophilic character with chloroform (85.6%) and xylol (57.6%) and a higher percentage of mucin adhesion (87.1%). However, strains KBS2 (84.8%) and KBL3 (89.5%) showed the highest autoaggregation values. In terms of adhesion to the intestinal epithelium in rats, strains KAS2, KAS3 and KAS4 showed values above 80%. The growth of the strains KAS2, KAS3, KAS4, KBS2, and KBL3 was inhibited by cefuroxime, cefotaxime, tetracycline, ampicillin, erythromycin, and cephalothin. Strains KBS2 (41.9% and 33.5%) and KBL3 (42.5% and 32.8%) had the highest co-aggregation values with S. aureus and E. coli. The results obtained in this study indicate that lactic acid bacteria isolated from tepache can be considered as candidates for potentially probiotic bacteria, laying the foundations to evaluate their probiotic functionality in vivo and thus to be used in the formulation of functional foods.

The prFMNH2-binding chaperone LpdD assists UbiD decarboxylase activation.

The UbiD enzyme family of prenylated flavin (prFMN)-dependent reversible decarboxylases is near ubiquitously present in microbes. For some UbiD family members, enzyme activation through prFMNH2 binding and subsequent oxidative maturation of the cofactor readily occurs, both in vivo in a heterologous host and through in vitro reconstitution. However, isolation of the active holo-enzyme has proven intractable for others, notably the canonical Escherichia coli UbiD. We show that E. coli heterologous expression of the small protein LpdD-associated with the UbiD-like gallate decarboxylase LpdC from Lactobacillus plantarum-unexpectedly leads to 3,4-dihydroxybenzoic acid decarboxylation whole-cell activity. This activity was shown to be linked to endogenous E. coli ubiD expression levels. The crystal structure of the purified LpdD reveals a dimeric protein with structural similarity to the eukaryotic heterodimeric proteasome assembly chaperone Pba3/4. Solution studies demonstrate that LpdD protein specifically binds to reduced prFMN species only. The addition of the LpdD-prFMNH2 complex supports reconstitution and activation of the purified E. coli apo-UbiD in vitro, leading to modest 3,4-dihydroxybenzoic acid decarboxylation. These observations suggest that LpdD acts as a prFMNH2-binding chaperone, enabling apo-UbiD activation through enhanced prFMNH2 incorporation and subsequent oxidative maturation. Hence, while a single highly conserved flavin prenyltransferase UbiX is found associated with UbiD enzymes, our observations suggest considerable diversity in UbiD maturation, ranging from robust autocatalytic to chaperone-mediated processes. Unlocking the full (de)carboxylation scope of the UbiD-enzyme family will thus require more than UbiX coexpression.

Philodulcilactobacillus myokoensis gen. nov., sp. nov., a fructophilic, acidophilic, and agar-phobic lactic acid bacterium isolated from fermented vegetable extracts.

Lactic acid bacteria are commonly in the fermentation industry and pose potential positive effects on health. In this study, a new lactic acid bacterium was isolated from fermented vegetable extracts in Myoko, Niigata, Japan. This bacterium is fructophilic, acidophilic, and hard to grow on agar medium. The isolate is Gram-stain-positive, non-spore-forming, non-motile, rod-shaped, and catalase-negative. Growth occurred at pH 3.5-5.5, with optimal growth at pH 4.5-5.0. The cells formed colonies on a solid MRS medium with 20% (w/v) sucrose and 0.8% (w/v) gellan gum under anaerobic conditions. The bacterium was able to grow on up to 50% (w/v) sucrose but not on d-glucose. Moreover, 16S rRNA gene sequence analysis revealed that the strain was most closely related to Apilactobacillus ozensis (93.1% sequence similarity). The values of average nucleotide identity, digital DNA-DNA hybridization, average amino acid sequence identity, and amino acid identity of conserved genes were calculated between the isolated strain (type strain is WR16-4T = NBRC 115064T = DSM 112857T) and its phylogenetically closest type strains. The average nucleotide identity values (73.36-78.28%) and DNA-DNA hybridization values (16.3-32.9%) were significantly lower than the threshold values for species boundaries. The average amino acid sequence identity values (53.96-60.88%) were significantly below the threshold boundary of genus demarcation (68%). The amino acid identity of conserved genes values compared to strain WR16-4T were the genera Apilactobacillus, Nicoliella spurrieriana SGEP1_A5T, Acetilactobacillus jinshanensis HSLZ-75T, and Fructilactobacillus were 62.51-63.79%, 62.87%, 62.03%, and 58.00-61.04%, respectively. The 16S rRNA gene and core genome phylogenetic trees suggested that this novel strain was most closely related to the type strain of A. jinshanensis HSLZ-75T. Based on the physiological, morphological, and phenotypical characteristics of strain WR16-4T, we propose its classification as a novel genus, Philodulcilactobacillus myokoensis gen. nov., sp. nov.

Activation of the toll-like receptor 2 signaling pathway by GAPDH from bacterial strain RD055328.

We characterized the membrane vesicle fraction (RD-MV fraction) from bacterial strain RD055328, which is related to members of the genus Companilactobacillus and Lactiplantibacillus plantarum. RD-MVs and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were detected in the RD-MV fraction. Immunoglobulin A (IgA) was produced by Peyer's patch cells following the addition of the RD-MV fraction. In the presence of the RD-MV fraction, RAW264 cells produced the pro-inflammatory cytokine IL-6. Recombinant GAPDH probably induced the production of IL-6 by RAW264 cells via superficial toll-like receptor 2 (TLR2) recognition. A confocal laser scanning microscopy image analysis indicated that RD-MVs and GAPDH were taken up by RAW264 cells. GAPDH wrapped around RAW264 cells. We suggest that GAPDH from strain RD055328 enhanced the production of IgA by acquired immune cells via the production of IL-6 by innate immune cells through TLR2 signal transduction.

Delving into the study of lactic acid bacteria and yeasts distribution in table olive biofilms using a non-destructive procedure.

To turn table olives into appropriate carriers of beneficial bacteria and yeasts to consumers, it is essential to have reliable methods for analysing microorganisms in biofilms. This work validates the application of a non-destructive procedure to study the lactic acid bacteria and yeasts distribution in fruits during Spanish-style green table olive fermentations. Laboratory-scale fermentations were inoculated simultaneously with three Lactiplantibacillus pentosus strains (LPG1, 119, and 13B4) and two yeasts (Wickerhamomyces anomalus Y12 and Saccharomyces cerevisiae Y30), all of them natives of table olive fermentations. Data showed that L. pentosus LPG1 and yeasts W. anomalus Y12 were quite prone to colonise olive biofilms, but only the Lactiplantibacillus strain also can penetrate the epidermis of the fruit and colonise the flesh. Applying a non-destructive treatment consisting in shelling the fruits with glass beads led to obtaining similar lactic acid bacteria and yeast recovery than the classical stomacher destructive method. However, the glass bead procedure improved the quality of the metagenomics analysis (especially when using 16 S rRNA gene-based sequencing). Results show the great utility of procedures that do not destroy the fruit for studying fermented vegetable biofilms.

A critical issue on microbiological cut-off value of ampicillin resistance in Lactiplantibacillus plantarum.

AIM: Comprehensive evaluation of antibiotic susceptibility patterns in Lactiplantibacillus plantarum strains isolated from grape marc, based on genomic and phenotypic assessment. METHODS AND RESULTS: We assessed the antibiotic resistance-susceptibility patterns of 20 L. plantarum strains for 16 antibiotics. Genomes of relevant strains were sequenced for in silico assessment and comparative genomic analysis. Results showed high MIC values for spectinomycin, vancomycin, and carbenicillin, indicating natural resistance to these antibiotics. Besides, these strains revealed MIC values for ampicillin higher than previously established by the EFSA, indicating the possible presence of acquired resistance genes in the genomes. However, genomic analysis by complete genome sequencing did not reveal presence of ampicillin resistance genes. CONCLUSION: Comparative genomic analysis between our strains and other L. plantarum genomes present in the literature showed several substantial genomic differences, and suggested the need to adjust the cut-off value for ampicillin in L. plantarum. However, further sequence analysis will reveal how these strains have acquired antibiotic resistance.

Metataxonomic insights in the distribution of Lactobacillaceae in foods and food environments.

Members of the family Lactobacillaceae, which now includes species formerly belonging to the genera Lactobacillus and Pediococcus, but also Leuconostocaceae, are of foremost importance in food fermentations and spoilage, but also as components of animal and human microbiota and as potentially pathogenic microorganisms. Knowledge of the ecological distribution of a given species and genus is important, among other things, for the inclusion in lists of microorganisms with a Qualified Presumption of Safety or with beneficial use. The objective of this work is to use the data in FoodMicrobionet database to obtain quantitative insights (in terms of both abundance and prevalence) on the distribution of these bacteria in foods and food environments. We first explored the reliability of taxonomic assignments using the SILVA v138.1 reference database with full length and partial sequences of the 16S rRNA gene for type strain sequences. Full length 16S rRNA gene sequences allow a reasonably good classification at the genus and species level in phylogenetic trees but shorter sequences (V1-V3, V3-V4, V4) perform much worse, with type strains of many species sharing identical V4 and V3-V4 sequences. Taxonomic assignment at the genus level of 16S rRNA genes sequences and the SILVA v138.1 reference database can be done for almost all genera of the family Lactobacillaceae with a high degree of confidence for full length sequences, and with a satisfactory level of accuracy for the V1-V3 regions. Results for the V3-V4 and V4 region are still acceptable but significantly worse. Taxonomic assignment at the species level for sequences for the V1-V3, V3-V4, V4 regions of the 16S rRNA gene of members of the family Lactobacillaceae is hardly possible and, even for full length sequences, and only 49.9 % of the type strain sequences can be unambiguously assigned to species. We then used the FoodMicrobionet database to evaluate the prevalence and abundance of Lactobacillaceae in food samples and in food related environments. Generalist and specialist genera were clearly evident. The ecological distribution of several genera was confirmed and insights on the distribution and potential origin of rare genera (Dellaglioa, Holzapfelia, Schleiferilactobacillus) were obtained. We also found that combining Amplicon Sequence Variants from different studies is indeed possible, but provides little additional information, even when strict criteria are used for the filtering of sequences.

Non-redundant nature of Lactiplantibacillus plantarum plasmidome revealed by comparative genomic analysis of 105 strains.

Lactiplantibacillus plantarum is a homofermentative lactic acid bacterium (LAB) most often found in fermented foods with many strains displaying probiotic properties. Strains belonging to L. plantarum are more stress tolerant and metabolically flexible than other lactobacilli and display larger genomes and higher plasmid abundance. This study aimed at understanding whether plasmids play a particular role in L. plantarum as compared to chromosomes by comparative genomic analysis. Assessment of chromosomes and 395 plasmids of 105 strains with publicly available complete genome sequences revealed that the majority of the plasmids encoded protein families (PFs) (57.6%) were not encoded by the chromosomes. The most abundant PFs unique to plasmids contained hypothetical proteins while others were involved in exopolysaccharides biosynthesis, biofilm formation, stress tolerance, and carbohydrate metabolism. The sequences of common plasmid-encoded and chromosome-encoded PFs differed from each other, suggesting that they might exhibit different biochemical properties. Common PF genes were predominantly present on larger plasmids pointing to another possible way to reduce redundancy by encoding shared PFs by low copy number plasmids. Overall, this study demonstrates the unique contributions of the plasmids to the versatility, survival, and evolutionary success of L. plantarum while also highlighting a need to functionally characterize hypothetical proteins encoded by them.

Correlation of inflammatory biomarkers with the diversity of Bacteroidaceae, Bifidobacteriaceae, Prevotellaceae and Lactobacillaceae families in the intestinal microbiota of patients with end stage renal disease.

PURPOSE: Serum levels of inflammatory cytokines and uremic toxins, and their inter-correlations with the diversity of Bacteroidaceae, Bifidobacteriaceae, Prevotellaceae and Lactobacillaceae families in intestinal microbiota were investigated in patients with end stage renal disease (ESRD). METHODS: Stool and blood samples from 20 ESRD patients on maintenance hemodialysis were collected. DNA genome of the bacterial composition of the stool samples was extracted and evaluated by the sequencing analysis of 16S rRNA genes. Serum levels of inflammatory cytokines and uremic toxins were then analyzed. RESULTS: The mean serum concentrations of TNF-α, IL-6, indoxyl sulfate (IS) and p-cresol (PC) were 305.99 â€‹± â€‹12.03 â€‹ng/L, 159.95 â€‹± â€‹64.22 â€‹ng/L, 36.76 â€‹± â€‹5.09 â€‹µg/mL and 0.39 â€‹± â€‹0.15 â€‹µg/mL, respectively. The most significant positive correlation was observed between Prevotellaceae family and total antioxidant capacity (TAC), Lactobacilli species and CRP and PC, as well as Scardovia wiggsiae and IS (p â€‹< â€‹0.001). A negative correlation was also found between Bacteroides clarus and PC. Patients with ESRD on maintenance hemodialysis had elevated levels of PC and IS and increased levels of the inflammatory markers. The most positive correlation was found between microbiota and CRP and PC, while the most negative one was between microbiota and IL-1 and TAC. CONCLUSIONS: The abundance and diversity of Bacteroidaceae, Bifidobacteriaceae, Prevotellaceae and Lactobacillaceae families and their correlations with clinical parameters could provide benefits in the ESRD patients but they could not promote the symptoms.

Lactiplantibacillus plantarum J-15 reduced calcium oxalate kidney stones by regulating intestinal microbiota, metabolism, and inflammation in rats.

The prevention role of Lactiplantibacillus plantarum against the formation of kidney stones has been increasingly recognized; its mechanism, however, has mainly been focused on inhibiting the inflammation in the colon in the gastrointestinal (GI) system, and the intestinal metabolites from microflora have not been revealed fully with regarding to the stone formation. In this study, we investigated the effect of L. plantarum J-15 on kidney stone formation in renal calcium oxalate (CaOx) rats induced by ethylene glycol and monitored the changes of intestinal microflora and their metabolites detected by 16S rRNA sequencing and widely targeted analysis, followed by the evaluation of the intestinal barrier function and inflammation levels in the colon, blood and kidney. The results showed that L. plantarum J-15 effectively reduced renal crystallization and urinary oxalic acid. Ten microbial genera, including anti-inflammatory and SCFAs-related Faecalibaculum, were enriched in the J-15 treatment group. There are 136 metabolites from 11 categories significantly different in the J-15 supplementation group compared with CaOx model rats, most of which were enriched in the amino acid metabolic and secondary bile acid pathways. The expression of intestinal tight junction protein Occludin and the concentration of pro-inflammatory cytokines and prostaglandin were decreased in the intestine, which further reduced the translocated lipopolysaccharide and inflammation levels in the blood upon J-15 treatment. Thus, the inflammation and injury in the kidney might be alleviated by downregulating TLR4/NF-κB/COX-2 signaling pathway. It suggested that L. plantarum J-15 might reduce kidney stone formation by restoring intestinal microflora and metabolic disorder, protecting intestinal barrier function, and alleviating inflammation. This finding provides new insights into the therapies for renal stones.

Characterization of the microbial community in ripened Pecorino Toscano cheese affected by pink discoloration.

Pink discoloration defect can cause economic losses for cheese producers due to the impossibility to sell the defected cheese, but few knowledge is currently available on the causes of this defect. To gain more insight on the causes that lead to the formation of pink discoloration in Pecorino Toscano cheese with the Protected Designation of Origin (PDO) status, the bacterial community in defected and not defected cheese was characterized by high-throughput sequencing of bacterial 16S rRNA gene. The bacterial community in the defected cheese significantly differed compared to the control. The relative abundance of the genera Acidipropionibacterium, Enterococcus, Escherichia/Shigella, Lactobacillus, Lentilactobacillus and Propionibacterium was higher in the cheese with pink discoloration defect. The concentration of short chain fatty acids and of lactic acid in cheese was measured and a shift towards the production of propionate in the cheese with pink discoloration defect was observed. Furthermore, the possible involvement of microbially produced vitamin B12 in the formation of pink discoloration was not supported by the data, since a tendency to a lower concentration of vitamin B12 was measured in the defected cheese compared to the control.

Exploring the genome of Lactobacillaceae spp. Sy-1 isolated from Heterotrigona itama honey.

Background: Honey produced by Heterotrigona itama is highly preferred among consumers due to its high-value as a functional food and beneficial lactic acid bacteria (LAB) reservoir. Fructophilic lactic acid bacteria (FLAB) are a group of LAB with unique growth characteristics and are regarded as promising producers of bioactive compounds. Hence, it is not surprising that LAB, especially FLAB, may be involved with the excellent bioactivity of H. itama honey. With the trending consumer preference for H. itama honey coupled with increasing awareness for healthy food, the genomic background of FLAB isolated from this honey must, therefore, be clearly understood. In this study, one FLAB strain designated as Sy-1 was isolated from freshly collected H. itama honey. Its FLAB behavior and genomic features were investigated to uncover functional genes that could add value to functional food. Methods: The fructophilic characteristics of strain Sy-1 were determined, and the genome was sequenced using Illumina iSeq100 and Oxford Nanopore. The average nucleotide identity and phylogenetic analyses based on 16S rRNA, 92 core genes, and whole-genome sequence were performed to unravel the phylogenetic position of strain Sy-1. NCBI Prokaryotic Genome Annotation Pipeline annotated the genome, while the EggNOG-mapper, BLASTKoala, and GHOSTKoala were used to add functional genes and pathways information. Results: Strain Sy-1 prefers D-fructose over D-glucose and actively metabolizes D-glucose in the presence of electron acceptors. Genomic annotation of strain Sy-1 revealed few genes involved in carbohydrate transport and metabolism, and partial deletion of adhE gene, in line with the characteristic of FLAB. The 16S rRNA gene sequence of strain Sy-1 showed the highest similarity to unknown LAB species isolated from the gut of honeybees. The phylogenetic analyses discovered that strain Sy-1 belonged to the Lactobacillaceae family and formed a separate branch closer to type strain from the genera of Acetilactobacillus and Apilactobacillus. The ANI analysis showed the similarity of the closest relative, Apilactobacillus micheneri Hlig3T. The assembled genome of Sy-1 contains 3 contigs with 2.03 Mbp and a 41% GC content. A total of 1,785 genes were identified, including 1,685 protein-coding genes, 68 tRNA, and 15 rRNA. Interestingly, strain Sy-1 encoded complete genes for the biosynthesis of folate and riboflavin. High-performance liquid chromatography analysis further confirmed the high production of folic acid (1.346 mg/L) by Sy-1. Discussion: Based on phylogenetic and biochemical characteristics, strain Sy-1 should be classified as a novel genus in the family of Lactobacillaceae and a new member of FLAB. The genome information coupled with experimental studies supported the ability of strain Sy-1 to produce high folic acid. Our collective findings support the suitable application of FLAB strain Sy-1 in the functional food and pharmaceutical industries.

Extracellular electron transfer increases fermentation in lactic acid bacteria via a hybrid metabolism.

Energy conservation in microorganisms is classically categorized into respiration and fermentation; however, recent work shows some species can use mixed or alternative bioenergetic strategies. We explored the use of extracellular electron transfer for energy conservation in diverse lactic acid bacteria (LAB), microorganisms that mainly rely on fermentative metabolism and are important in food fermentations. The LAB Lactiplantibacillus plantarum uses extracellular electron transfer to increase its NAD+/NADH ratio, generate more ATP through substrate-level phosphorylation, and accumulate biomass more rapidly. This novel, hybrid metabolism is dependent on a type-II NADH dehydrogenase (Ndh2) and conditionally requires a flavin-binding extracellular lipoprotein (PplA) under laboratory conditions. It confers increased fermentation product yield, metabolic flux, and environmental acidification in laboratory media and during kale juice fermentation. The discovery of a single pathway that simultaneously blends features of fermentation and respiration in a primarily fermentative microorganism expands our knowledge of energy conservation and provides immediate biotechnology applications.

Bacteria produce the energy they need to live through two processes, respiration and fermentation. While respiration is often more energetically efficient, many bacteria rely on fermentation as their sole means of energy production. Respiration normally depends on the presence of small soluble molecules, such as oxygen, that can diffuse inside the cell, but some bacteria can use metals or other insoluble compounds found outside the cell to perform 'extracellular electron transfer'. Lactic acid bacteria are a large group of bacteria that have several industrial uses and live in many natural environments. These bacteria survive using fermentation, but they also carry a group of genes needed for extracellular electron transfer. It is unclear whether they use these genes for respiration or if they have a different purpose. Tejedor-Sanz, Stevens et al. used a lactic acid bacterium called Lactiplantibacillus plantarum to study whether and how this group of bacteria use extracellular electron transfer. Analysis of L. plantarum and its effect on its surroundings showed that these bacteria use a hybrid process to produce energy: the cells use aspects of extracellular respiration to increase the yield and efficiency of fermentation. Combining these two approaches may allow L. plantarum to adapt to different environments and grow faster, allowing it to compete against other species. Tejedor-Sanz, Stevens et al. provide new information on a widespread group of bacteria that are often used in food production and industry. The next step will be to understand how the hybrid system is controlled and how it varies among species. Understanding this process could result in new biotechnologies and foods that are healthier, produce less waste, or have different tastes and textures.

Bioprocess development for bacterial cellulose biosynthesis by novel Lactiplantibacillus plantarum isolate along with characterization and antimicrobial assessment of fabricated membrane.

Bacterial cellulose (BC) is an ecofriendly biopolymer with diverse commercial applications. Its use is limited by the capacity of bacterial production strains and cost of the medium. Mining for novel organisms with well-optimized growth conditions will be important for the adoption of BC. In this study, a novel BC-producing strain was isolated from rotten fruit samples and identified as Lactiplantibacillus plantarum from 16S rRNA sequencing. Culture conditions were optimized for supporting maximal BC production using one variable at a time, Plackett-Burman design, and Box Behnken design approaches. Results indicated that a modified Yamanaka medium supported the highest BC yield (2.7 g/l), and that yeast extract, MgSO4, and pH were the most significant variables influencing BC production. After optimizing the levels of these variables through Box Behnken design, BC yield was increased to 4.51 g/l. The drug delivery capacity of the produced BC membrane was evaluated through fabrication with sodium alginate and gentamycin antibiotic at four different concentrations. All membranes (normal and fabricated) were characterized by scanning electron microscope, Fourier transform-infrared spectroscopy, X-ray diffraction, and mechanical properties. The antimicrobial activity of prepared composites was evaluated by using six human pathogens and revealed potent antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus mutans, with no detected activity against Pseudomonas aeruginosa and Candida albicans.

Probiotic activity traits in vitro and production of antimicrobial peptides by Lactobacillaceae isolates from pulque using Lactobacillus acidophilus NCFM as control.

The objective of this work was to determine in vitro probiotic activity traits of 11 lactic acid bacteria (LAB) strains isolated from pulque obtained from three different locations in the Mexican states of Oaxaca and Puebla using the probiotic strain Lactobacillus acidophilus NCFM as a positive control, and to detect their production of antimicrobial peptides, including bacteriocins and peptidoglycan hydrolases (PGH). The LAB isolates were identified by sequencing of their 16S rRNA as belonging to four different genera of the Lactobacillaceae family: Lactiplantibacillus, Levilactobacillus, Lacticaseibacillus and Liquorilactobacillus, corresponding to the species plantarum, brevis, paracasei and ghanensis, respectively. Most of the strains showed resistance to high acidity (pH 2) and bile salts (0.5%), with survival rates up to 87 and 92%, respectively. In addition, most of the strains presented good antimicrobial activity against the foodborne pathogens Listeria monocytogenes, ECEC and Salmonella Typhi. The strain Liquorilactobacillus ghanensis RVG6, newly reported in pulque, presented an outstanding overall performance on the probiotic activity tests. In terms of their probiotic activity traits assessed in this work, the strains compared positively with the control L. acidophilus NCFM, which is a very-well documented probiotic strain. For the antimicrobial peptide studies, four strains presented bacteriocin-like mediated antibiosis and six had significant PGH activity, with two strains presenting outstanding overall antimicrobial peptide production: Lacticaseibacillus paracasei RVG3 and Levilactobacillus brevis UTMB2. The probiotic performance of the isolates was mainly dependent on strain specificity. The results obtained in this work can foster the revalorization of pulque as a functional natural product.

Improved antimicrobial spectrum of the N-acetylmuramoyl-L-alanine amidase from Latilactobacillus sakei upon LysM domain deletion.

The gene encoding N-acetylmuramoyl-L-alanine amidase in Latilactobacillus sakei isolated from a fermented meat product was cloned in two forms: its complete sequence (AmiC) and a truncated sequence without one of its anchoring LysM domains (AmiLysM4). The objective of this work was to evaluate the effect of LysM domain deletion on antibacterial activity as well the biochemical characterization of each recombinant protein. AmiC and AmiLysM4 were expressed in Escherichia coli BL21. Using a zymography method, two bands with lytic activity were observed, which were confirmed by LC-MS/MS analysis, with molecular masses of 71 kDa (AmiC) and 66 kDa (AmiLysM4). The recombinant proteins were active against Listeria innocua and Staphylococcus aureus strains. The inhibitory spectrum of AmiLysM4 was broader than AmiC as it showed inhibition of Leuconostoc mesenteroides and Weissella viridescens, both microorganisms associated with food decomposition. Optimal temperature and pH values were determined for both proteins using L-alanine-p-nitroanilide hydrochloride as a substrate for N-acetylmuramoyl-L-alanine amidase activity. Both proteins showed similar maximum activity values for pH (8) and temperature (50 °C). Furthermore, structural predictions did not show differences for the catalytic region, but differences were found for the region called 2dom-AmiLysM4, which includes 4 of the 5 LysM domains. Therefore, modification of the LysM domain offers new tools for the development of novel food biopreservatives.

Limosilactobacillus caccae sp. nov., a new bacterial species isolated from the human gut microbiota.

Strain Marseille-P3519T isolated from the fecal flora of a 25-year-old healthy French woman was a Gram-positive anaerobic bacterium, non-motile and non-spore forming. The 16S rRNA gene sequence of Marseille-P3519 showed 97.73% of sequence similarity with Limosilactobacillus reuteri DSM 20016, the closest species, phylogenetically. Furthermore, the average nucleotide identity of strain Marseille-3519 with its closest related species was 75.8% that was very below the recommended threshold (>95-96%). Its genome had 2 237 367 bp with 45.42 mol% of G + C content. Major fatty acids were C16:0 (50.8%), C18:1n9 (18.0%), C18:2n6 (9.8%) and C19:1n9 (8.9%). It was catalase negative and fermented glycerol, glucose, fructose, D-maltose, lactose and mannose. These findings support that strain Marseille-P3519 ( = CSURP3519 = CECT 30110) is a new member of the genus Limosilactobacillus for which the name Limosilactobacillus caccae sp. nov., is proposed.

A sugar utilization phenotype contributes to the formation of genetic exchange communities in lactic acid bacteria.

In prokaryotes, a major contributor to genomic evolution is the exchange of genes via horizontal gene transfer (HGT). Areas with a high density of HGT networks are defined as genetic exchange communities (GECs). Although some phenotypes associated with specific ecological niches are linked to GECs, little is known about the phenotypic influences on HGT in bacterial groups within a taxonomic family. Thanks to the published genome sequences and phenotype data of lactic acid bacteria (LAB), it is now possible to obtain more detailed information about the phenotypes that affect GECs. Here, we have investigated the relationship between HGT and internal and external environmental factors for 178 strains from 24 genera in the Lactobacillaceae family. We found a significant correlation between strains with high utilization of sugars and HGT bias. The result suggests that the phenotype of the utilization of a variety of sugars is key to the construction of GECs in this family. This feature is consistent with the fact that the Lactobacillaceae family contributes to the production of a wide variety of fermented foods by sharing niches such as those in vegetables, dairy products and brewing-related environments. This result provides the first evidence that phenotypes associated with ecological niches contribute to form GECs in the LAB family.