BackgroundProbiotic microorganisms favorably alter the intestinal microflora balance, promote intestinal integrity and mobility, inhibit the growth of harmful bacteria and increase resistance to infection. Probiotics are increasingly used in nutraceuticals, functional foods or in microbial interference treatment. However, the effectiveness of probiotic organism is considered to be population-specific due to variation in gut microflora, food habits and specific host-microbial interactions. Most of the probiotic strains available in the market are of western or European origin, and a strong need for exploring new indigenous probiotic organisms is felt.Methods and FindingsAn indigenous isolate Lp9 identified as Lactobacillus plantarum by molecular-typing methods was studied extensively for its functional and probiotic attributes, viz., acid and bile salt tolerance, cell surface hydrophobicity, autoaggregation and Caco-2 cell-binding as well as antibacterial and antioxidative activities. Lp9 isolate could survive 2 h incubation at pH 1.5–2.0 and toxicity of 1.5–2.0% oxgall bile. Lp9 could deconjugate major bile salts like glycocholate and deoxytaurocholate, indicating its potential to cause hypocholesterolemia. The isolate exhibited cell-surface hydrophobicity of ∼37% and autoaggregation of ∼31%. Presence of putative probiotic marker genes like mucus-binding protein (mub), fibronectin-binding protein (fbp) and bile salt hydrolase (bsh) were confirmed by PCR. Presence of these genes suggested the possibility of specific interaction and colonization potential of Lp9 isolate in the gut, which was also suggested by a good adhesion ratio of 7.4±1.3% with Caco-2 cell line. The isolate demonstrated higher free radical scavenging activity than standard probiotics L. johnsonii LA1 and L. acidophilus LA7. Lp9 also exhibited antibacterial activity against E. coli, L. monocytogenes, S. typhi, S. aureus and B. cereus.ConclusionThe indigenous Lactobacillus plantarum Lp9 exhibited high resistance against low pH and bile and possessed antibacterial, antioxidative and cholesterol lowering properties with a potential for exploitation in the development of indigenous functional food or nutraceuticals.

Background & objectives:Adherence of bacteria to epithelial cells and mucosal surfaces is a key criterion for selection of probiotic. We assessed the adhesion property of selected indigenous probiotic Lactobacillus strains based on their hydrophobicity and ability to adhere to human epithelial cells.Methods:Five human faecal Lactobacillus isolates, one from buffalo milk and one from cheese were assessed for hydrophobicity following the microbial adhesion to hydrocarbons (MATH) method and colonization potentials based on their adherence to Caco2 and HT-29 colonic adenocarcinomal human intestinal epithelial cell lines. Lactobacillus strains that adhered to Caco2 and HT-29 cell lines were quantified by plating after trypsinization and simultaneously the adhered bacteria were also examined microscopically after staining with Geimsa stain and counted in different fields.Results:Among the tested faecal isolates, L. plantarum Lp91 showed maximum percentage hydrophobicity (35.73±0.40 for n-hexadecane and 34.26±0.63 for toluene) closely followed by L. plantarum Lp9 (35.53±0.29 for n-hexadecane and 33.00±0.57 for toluene). Based on direct adhesion to epithelial cells, L. plantarum Lp91 was the most adhesive strain to HT-29 and Caco2 cell lines with per cent adhesion values of 12.8 ± 1.56 and 10.2 ± 1.09, respectively. L. delbrukeii CH4, was the least adhesive with corresponding figures of 2.5 ± 0.37 and 2.6 ± 0.20 per cent on HT-29 and Caco2 cell lines. Adhesion of the six isolated Lactobacillus strain to HT-29 cell and Caco2 lines as recorded under microscope varied between 131.0 ± 13.9 (Lp75) to 342.7 ± 50.52 (Lp91) and 44.7 ± 9.29 (CH4) to 315.7± 35.4 (Lp91), respectively.Interpretation & conclusions:Two Indigenous probiotic Lactobacillus strains (Lp9, Lp91) demonstrated their ability to adhere to epithelial cell and exhibited strong hydrophobicity under in vitro conditions, and thus could have better prospects to colonize the gut with extended transit

Probiotics can affect the immune homeostasis by altering the gut microbial balance and enhancing the immune system of gut, thus benefits in Inflammatory Bowel Disease, including Crohn's disease and Ulcerative colitis. Relative gene expression of pro, anti-inflammatory cytokines and other molecules in 2,4,6-trinitrobenzene sulfonic acid-induced colitis mouse model against Lactobacillus plantarum Lp91 (L. plantarum Lp91) was investigated by reverse transcription-quantitative PCR (RT-qPCR) using relative expression software tool (REST 2008 V2.0.7). L. plantarum Lp91 evoked significant down regulation of TNF-α and COX2 to 0.026 and 0.077 fold in colitis mouse model. No significant difference in expression of IL-12a cytokine in colitis mouse challenged with L. plantarum Lp91 was also observed. IL-10 was significantly up-regulated to 37.813 and 1.327 fold in colitis and non-colitis mouse challenged with L. plantarum Lp91. While, other anti-inflammatory markers i.e. COX1, IL-4 and IL-6 were significantly up regulated in colitis mouse challenged with L. plantarum Lp91. MUC2 gene was significantly up regulated to 2.216 fold in non-colitis group. L. plantarum Lp91, an indigenous probiotic culture, the main subject of this project exhibited strong immunemodulatory properties under in vivo conditions in mouse colitis model.

This is a repository copy of Effects of folic acid esterification on the hierarchical structure of amylopectin corn starch.

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