Variation of mucin adhesion, cell surface characteristics, and molecular mechanisms among Lactobacillus plantarum isolated from different habitats

The adhesion ability to mucin varied greatly among 18 Lactobacillus plantarum isolates depending on their isolation habitats. Such ability remained at high level even though they were sequentially exposed to the gastrointestinal (GI) stresses. The majority of L. plantarum isolated from shrimp intestine and about half of food isolates exhibited adhesion ability (51.06-55.04%) about the same as the well-known adhesive L. plantarum 299v. Interestingly, five infant isolates of CIF17A2, CIF17A4, CIF17A5, CIF17AN2, and CIF17AN8 exhibited extremely high adhesion ranging from 62.69 to 72.06%. Such highly adhesive property correlating to distinctively high cell surface hydrophobicity was significantly weaken after pretreatment with LiCl and guanidine-HCl confirming the entailment of protein moiety. Regarding the draft genome information, all molecular structures of major cell wall-anchored proteins involved in the adhesion based on L. plantarum WCSF1, including lp_0964, lp_1643, lp_3114, lp_2486, lp_3127, and lp_3059 orthologues were detected in all isolates. Exceptionally, the gene-trait matching between yeast agglutination assay and the relevant mannose-specific adhesin (lp_1229) encoding gene confirmed the Msa absence in five infant isolates expressed distinctively high adhesion. Interestingly, the predicted flagellin encoding genes (fliC) firstly revealed in lp_1643, lp_2486, and lp_3114 orthologues may potentially contribute to such highly adhesive property of these isolates.Peer reviewe

Micropropagation through adventitious shoot regeneration from leaf culture of Torenia fournieri Lind.

A tissue culture system was established from young leaves of in vitro grown seedling of Torenia fournieri Lind. Leafsegments were cultured on Murashige and Skoog medium (MS) medium supplemented with combinations of NAA and BA. Shoot organogenesis was observed in all growth regulators containing medium. High frequency regeneration was obtained from leaves cultured on MS medium supplemented with 0.05 mg/l NAA plus 3 mg/l BA. When individual isolated shoots were transferred to MS medium devoid of growth regulators, complete plantlets were obtained. Adventitious shoots were also regenerated from callus that was derived from leaf explants and a high frequency of shoot organogenesis was found on MSmedium containing 0.1 mg/l NAA plus 3 mg/l BA

Screening of lactic acid bacteria from gastrointestinal tracts of marine fish for their potential use as probiotics

One hundred and sixty isolates of lactic acid bacteria (LAB) with inhibitory activity against pathogenic Escherichia coli were isolated from gastrointestinal tracts of fish, shrimp and shellfish. One hundred and sixteen isolates were obtained from fish, twenty isolates from shrimp and twenty-four isolates from shellfish. Three strains were selected based on their bile and acid tolerances. All acid-tolerant strains showed inhibitory activity against human pathogens, including Staphylococcus aureus, Listeria monocytogenes, Salmonella sp. and Escherichia coli. However, the antibacterial activities were lost when the culture supernatants were neutralized to pH 6.5- 7.0 and treated with catalase, indicating that the inhibition may be contributed by acid and hydrogen-peroxide production of the strains. Nucleotide sequences of their 16s rDNA showed 98% (655/668 bp), 97% (691/712 bp) and 98% (492/501 bp) homology to Pediococcus pentosaceus LM2, Pediococcus pentosaceus SL4 and Enterococcus faecium SF, respectively

Variation of mucin adhesion, cell surface characteristics, and molecular mechanisms among Lactobacillus plantarum isolated from different habitats

The adhesion ability to mucin varied greatly among 18 Lactobacillus plantarum isolates depending on their isolation habitats. Such ability remained at high level even though they were sequentially exposed to the gastrointestinal (GI) stresses. The majority of L. plantarum isolated from shrimp intestine and about half of food isolates exhibited adhesion ability (51.06–55.04%) about the same as the well-known adhesive L. plantarum 299v. Interestingly, five infant isolates of CIF17A2, CIF17A4, CIF17A5, CIF17AN2, and CIF17AN8 exhibited extremely high adhesion ranging from 62.69 to 72.06%. Such highly adhesive property correlating to distinctively high cell surface hydrophobicity was significantly weaken after pretreatment with LiCl and guanidine-HCl confirming the entailment of protein moiety. Regarding the draft genome information, all molecular structures of major cell wall-anchored proteins involved in the adhesion based on L. plantarum WCSF1, including lp_0964, lp_1643, lp_3114, lp_2486, lp_3127, and lp_3059 orthologues were detected in all isolates. Exceptionally, the gene-trait matching between yeast agglutination assay and the relevant mannose-specific adhesin (lp_1229) encoding gene confirmed the Msa absence in five infant isolates expressed distinctively high adhesion. Interestingly, the predicted flagellin encoding genes (fliC) firstly revealed in lp_1643, lp_2486, and lp_3114 orthologues may potentially contribute to such highly adhesive property of these isolates.</p

An Inducible Operon Is Involved in Inulin Utilization in Lactobacillus plantarum Strains, as Revealed by Comparative Proteogenomics and Metabolic Profiling

The draft genomes of Lactobacillus plantarum strains isolated from Asian fermented foods, infant feces, and shrimp intestines were sequenced and compared to those of well-studied strains. Among 28 strains of L. plantarum, variations in the genomic features involved in ecological adaptation were elucidated. The genome sizes ranged from approximately 3.1 to 3.5 Mb, of which about 2,932 to 3,345 protein-coding sequences (CDS) were predicted. The food-derived isolates contained a higher number of carbohydrate metabolism-associated genes than those from infant feces. This observation correlated to their phenotypic carbohydrate metabolic profile, indicating their ability to metabolize the largest range of sugars. Surprisingly, two strains (P14 and P76) isolated from fermented fish utilized inulin. β-Fructosidase, the inulin-degrading enzyme, was detected in the supernatants and cell wall extracts of both strains. No activity was observed in the cytoplasmic fraction, indicating that this key enzyme was either membrane-bound or extracellularly secreted. From genomic mining analysis, a predicted inulin operon of fosRABCDXE, which encodes β-fructosidase and many fructose transporting proteins, was found within the genomes of strains P14 and P76. Moreover, pts1BCA genes, encoding sucrose-specific IIBCA components involved in sucrose transport, were also identified. The proteomic analysis revealed the mechanism and functional characteristic of the fosRABCDXE operon involved in the inulin utilization of L. plantarum. The expression levels of the fos operon and pst genes were upregulated at mid-log phase. FosE and the LPXTG-motif cell wall anchored β-fructosidase were induced to a high abundance when inulin was present as a carbon source