Molecular Cloning, Expression of minD Gene from Lactobacillus acidophilus VTCC-B-871 and Analyses to Identify Lactobacillus rhamnosus PN04 from Vietnam Hottuynia cordata Thunb

Homologous genes shared between probiotics and pathogens affect the adhesion of probiotics and exclusion of pathogens in the gut mucus of shrimp

Clarifying mechanisms underlying the selective adhesion of probiotics and competitive exclusion of pathogens in the intestine is a central theme for shrimp health. Under experimental manipulation of probiotic strain (i.e., Lactiplantibacillus plantarum HC-2) adhesion to the shrimp mucus, this study tested the core hypothesis that homologous genes shared between probiotic and pathogen would affect the adhesion of probiotics and exclusion of pathogens by regulating the membrane proteins of probiotics. Results indicated that the reduction of FtsH protease activity, which significantly correlated with the increase of membrane proteins, could increase the adhesion ability of L. plantarum HC-2 to the mucus. These membrane proteins mainly involved in transport (glycine betaine/carnitine/choline ABC transporter choS, ABC transporter, ATP synthase subunit a atpB, amino acid permease) and regulation of cellular processes (histidine kinase). The genes encoding the membrane proteins were significantly (p < 0.05) up-regulated except those encoding ABC transporters and histidine kinases in L. plantarum HC-2 when co-cultured with Vibrio parahaemolyticus E1, indicating that these genes could help L. plantarum HC-2 to competitively exclude pathogens. Moreover, an arsenal of genes predicted to be involved in carbohydrate metabolism and bacteria-host interactions were identified in L. plantarum HC-2, indicating a clear strain adaption to host's gastrointestinal tract. This study advances our mechanistic understanding of the selective adhesion of probiotics and competitive exclusion of pathogens in the intestine, and has important implications for screening and applying new probiotics for maintaining gut stability and host health.

Identification and expression analysis of MinD gene involved in plastid division in cassava

Cassava is a tropical crop known for its starchy root and excellent properties. Considering that starch biosynthesis in the amyloplast is affected by its division, it appears conceivable that the regulation of plastid division plays an important role in starch accumulation. As a member of the Min system genes, MinD participated in the spatial regulation of the position of the plastid division site.In our studies, sequence analysis and phylogenetic analysis showed that MeMinD has been highly conserved during the evolutionary process. Subcellular localisation indicated that MeMinD carries a chloroplast transit peptide and was localised in the chloroplast. Overexpression of MeMinD resulted in division site misplacement and filamentous formation in E. coli, indicating that MeMinD protein was functional across species. MeMinD exhibited different spatial and temporal expression patterns which was highly expressed in the source compared to that in the sink organ.

Detection of the Potential Inactivation of Tetrodotoxin by Lactic Acid Bacterial Exopolysaccharide

Screening for compounds that can neutralize the toxicity of tetrodotoxin (TTX) or reduce its negative effects is necessary. Our study tested the TTX detoxification capacity of exopolysaccharide (EPS) extracted from lactic acid bacteria. EPS of Leuconostoc mesenteroides N3 isolated from the Vung Tau sea (Vietnam), Lactobacillus plantarum PN05, and Lactobacillus rhamnosus PN04 were used in the study. To more completely evaluate the importance of EPS in detoxification, EPS samples of Leuconostoc mesenteroides N3, Lactobacillus plantarum PN05 and Lactobacillus rhamnosus PN04 were also tested. The majority of EPS of these bacteria contained glucose; this was observed using thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) analysis. As observed with FTIR analysis, only EPS of Lactobacillus plantarum PN05 contained methyl groups. The results indicated that detoxification of TTX in mice could be obtained at an optimal dose of 248 µg EPS from Leuconostoc mesenteroides incubated with 54 µg cuprous oxide for 40 min or 148 µg EPS Lactobacillus rhamnosus incubated with 55 µg cuprous oxide for 40 min, while EPS from Lactobacillus plantarum showed TTX detoxification capacity without cuprous oxide combination. Consequently, EPS from Lactobacillus plantarum PN05 can be used in TTX prevention. This is the first report on the importance of lactic acid bacteria in TTX detoxification.

Comparative Genomics Reveals Biomarkers to Identify Lactobacillus Species

Bacteria possessing multiple copies of 16S rRNA (rrs) gene demonstrate high intragenomic heterogeneity. It hinders clear distinction at species level and even leads to overestimation of the bacterial diversity. Fifty completely sequenced genomes belonging to 19 species of Lactobacillus species were found to possess 4-9 copies of rrs each. Multiple sequence alignment of 268 rrs genes from all the 19 species could be classified into 20 groups. Lactobacillus sanfranciscensis TMW 1.1304 was the only species where all the 7 copies of rrs were exactly similar and thus formed a distinct group. In order to circumvent the problem of high heterogeneity arising due to multiple copies of rrs, 19 additional genes (732-3645 nucleotides in size) common to Lactobacillus genomes, were selected and digested with 10 Type II restriction endonucleases (RE), under in silico conditions. The following unique gene-RE combinations: recA (1098 nts)-HpyCH4 V, CviAII, BfuCI and RsaI were found to be useful in identifying 29 strains representing 17 species. Digestion patterns of genes-ruvB (1020 nts), dnaA (1368 nts), purA (1290 nts), dnaJ (1140 nts), and gyrB (1944 nts) in combination with REs-AluI, BfuCI, CviAI, Taq1, and Tru9I allowed clear identification of an additional 14 strains belonging to 8 species. Digestion pattern of genes recA, ruvB, dnaA, purA, dnaJ and gyrB can be used as biomarkers for identifying different species of Lactobacillus.