Pili in Probiotic Bacteria

The ability to adhere to intestinal epithelial tissue and mucosal surfaces is a key criterion in selecting probiotics. Adhesion is considered to be a prerequisite for successful colonization and survival in the gastrointestinal tract to provide persistent beneficial effects to the host. Bacteria express a multitude of surface components that mediate adherence. Pili or fimbriae are surface adhesive components implicated in initiating bacterial adhesion and mediating interaction with the host. These nonflagellar proteinaceous fiber appendages were identified and explored over several decades in pathogenic bacteria, and many distinct types are known. However, the presence of pili in probiotics and/or commensalic bacteria has only recently been recognized. Thus knowledge about pili in probiotics is relatively limited, but structural and functional data have begun to emerge. Availability of these data in the future would enable us to understand the pili-mediated adhesion strategies of probiotics. This knowledge could be utilized to develop antiadhesion-based therapies against bacterial infections as well as probiotic designs for beneficial effects. This chapter will briefly summarize the current knowledge of pili in probiotics with emphasis on members of lactobacilli and bifidobacteria

Chemical composition and antioxidant capacities of phytococktail extracts from trans-Himalayan cold desert

BACKGROUND: Himalayan plants are widely used in traditional system of medicine both as prophylactics and therapeutics for high altitude maladies. Our aim was to evaluate the antioxidant capacities and bioactive compounds of methanol and n-hexane extracts of the phytococktail comprising of sea buckthorn (Hippophae rhamnoides), apricot (Prunus armeniaca) and roseroot (Rhodiola imbricata) from trans-Himalaya. METHODS: The 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and nitric oxide (NO) radical scavenging capacities and lipid peroxidation inhibition (LPI) property of the extracts were determined. Total antioxidant power was determined by ferric reducing/antioxidant power (FRAP) assay. Total polyphenol, flavonoid, flavonol, proanthocyanidin and carotenoid were also estimated for both extracts. We have identified and quantified the phyto-chemotypes present in the methanol and n-hexane extracts by hyphenated gas chromatography/mass spectrometry (GC/MS) technique. RESULTS: Antioxidant capacity assays using DPPH, ABTS, NO, LPI and FRAP exhibited analogous results where the phytococktail showed high antioxidant action. The phytococktail was also found to possess high quantity of total polyphenol, flavonoid, flavonol and carotenoid. A significant and linear correlation was found between the antioxidant capacities and bioactive principles. A total of 32 phyto-chemotypes were identified from these extracts by GC/MS chemometric fingerprinting. Major phyto-chemotypes identified by GC/MS were glycosides, phenylpropanoids and derivatives, terpenoids, alkaloids, phytosterols, fatty acids and esters, alkaloids and derivatives, organic acid esters and aromatic ethers with positive biological and pharmacological actions. CONCLUSION: The phytococktail extracts were found to contain considerable amount of diverse bioactive compounds with high antioxidant capacities. The presence of hydrophilic and lipophilic antioxidants in the phytococktail could have contributed to the higher antioxidant values. Hence, the phytococktail could be used as natural source of antioxidants to ameliorate disorders associated with oxidative stress