Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant pathogen and one of the leading causes of nosocomial infection worldwide. Probiotic bacteria play a significant role in preventive or therapeutic interventions of gastrointestinal infections in human as well as animals. In this study, we have investigated the adhesion property of the probiotic strain Lactobacillus fermentum MTCC 8711 and its ability to prevent the adhesion of MRSA to human colon adenocarcinoma cells, Caco-2. We have shown that L. fermentum could efficiently adhere to the Caco-2 cells. Also, we have shown that L. fermentum significantly reduced MRSA adhesion to Caco-2 cells. Three types of experiments were performed to assess the anti-adhesion property of L. fermentum against MRSA. Inhibition (Caco-2 cells were pre-treated with L. fermentum, and subsequently MRSA was added), competition (both L. fermentum and MRSA were added to Caco-2 cells simultaneously), and displacement or exclusion (Caco-2 cells were pre-treated with MRSA, and subsequently L. fermentum was added). In all three experiments, adhesion of MRSA was significantly reduced. Interestingly, L. fermentum could efficiently displace the adhered MRSA, and hence this probiotic can be used for therapeutic applications also. In cytotoxicity assay, we found that L. fermentum per se was not cytotoxic, and also significantly reduced the MRSA-induced cytotoxicity. The protective effect occurred without affecting Caco-2 cell morphology and viability.

Lactobacillus fermentum is a lactic acid bacterium of probiotic importance, which is found ubiquitously in fermented milk products. Bile salt hydrolase (BSH) has a significant role in affording probiotic properties to lactobacilli. In the present study, two bsh genes encoding BSH1 and BSH2 were identified from the draft genome sequence of L. fermentum MTCC 8711. Nucleotide comparison revealed no significant similarity between bsh1 and bsh2 genes, whereas the deduced amino acid sequences showed 26 % sequence similarity between both BSH1 and BSH2. Pfam analysis revealed the presence of cys-2 active site residues in the catalytic pocket of both BSH1 and BSH2 highly essential for catalysis. Phylogentic analysis of BSH1 and BSH2 revealed the possible independent origin of these proteins in Lactobacillus. We cloned these genes in pSLp111.3, a Lactobacillus expression vector with signal peptide A (slpA) and expressed in the native L. fermentum strain for overexpression and extracellular secretion. The bsh1 gene failed to express and to produce promising BSH activity. However, bsh2 gene was overexpressed and the recombinant strain showed improved BSH activity. Induction of the recombinant strain with an optimal 2 % xylose concentration secreted 0.5 U/ml of the BSH into extracellular medium. Furthermore, the recombinant strain was able to completely assimilate the 100-μg/ml cholesterol within 24 h, whereas the native strain took 72 h for the complete assimilation of cholesterol.

Jayshree, et al.: Microalgae: Effective Health MediatorsAlgae are rich sources of structurally novel and biologically active metabolites. Primary and secondary metabolites produced by these organisms have drawn interest of the pharmaceutical industries. In this regard we have put forth an investigation to evaluate phenolic and flavonoid content in methanol extract of fresh algal biomass followed by antioxidant, antimicrobial and anticancer activities. Determination of total phenol and flavonoid content was followed by the 2,2-diphenyl-1-picrylhydrazyl radicals scavenging, phosphomolybdate and reducing power assay for evaluating antioxidant potency. Agar well diffusion method for antibacterial activity and trypan blue test along with MTT assay was done for anticancer activity. Among two microalgae, Chlorella vulgaris had efficiently high amount of total phenol and flavonoid content. Chlorella vulgaris is a single-celled eukaryotic green micro algae, known to be first form of a plant with a well-defined nucleus emerged over 2 billion years ago [1] . Chlorella contains the highest amount of chlorophyll of any known plant. Chlamydomonas reinhardtii, another unicellular algae though not much explored as nutrient supplement; it is well known model organism with its three genomes (nuclear, plastidial and mitochondrial) completely sequenced [2] . It finds its application mostly in molecular biology especially in studies involving flagellar motility, chloroplast dynamics, biogenesis and genetics [3] . C. vulgaris is well determined nutrientdense superfood containing 60% protein, 18 amino acids, 20 vitamins and minerals like iron, calcium, potassium, magnesium and phosphorous [4] . One of its unique properties is a phytonutrient called Chlorella Growth Factor [1] . These two microalgae are known for high volume production of β-carotene.Besides being food supplements microalgae, Chlorella sp., Chlamydomonas sp. have been proved to have antibacterial activity in vitro against both Gram positive and Gram negative bacteria [5] . The production of extracellular antibiotic metabolites by marine algae has been well studied in recent years. They are also been reported that a wide range of antifungal activities were obtained from extracts of green microalgae [6] . Eventually, microalgae are almost an untapped resource of natural antioxidants due to their enormous biodiversity, much more diverse than higher plants. They contain various biologically active compounds that are been used as source of food, feed and medicine [7] . Microalgae are

A novel antifungal peptide with 36 amino acids was identified by functional screening of a marine metagenomic library. The peptide did not show similarity with any existing antimicrobial peptide sequences in the databank. The108 bp ORF designated as mmgp1 was cloned and expressed in Escherichia coli BL21 (DE3) using pET expression system. Mass spectrometry analysis of the purified recombinant peptide revealed a molecular mass of 5026.9 Da. The purified recombinant peptide inhibited the growth of Candida albicans and Aspergillus niger. The peptide was predicted to adopt α- helical conformation with an extended coil containing a ligand binding site for N-acetyl-D-glucosamine. The α- helicity of the peptide was demonstrated by circular dichroism spectroscopy in the presence of chitin or membrane mimicking solvent, trifluoroethanol. The chitin binding property of the peptide was also confirmed by fast performance liquid chromatography.

The reciprocal interaction between rhizosphere bacteria and their plant hosts results in a complex battery of genetic and physiological responses. In this study, we used insertion sequencing (INSeq) to reveal the genetic determinants responsible for the fitness of Pseudomonas aeruginosa PGPR2 during root colonization. We generated a random transposon mutant library of Pseudomonas aeruginosa PGPR2 comprising 39,500 unique insertions and identified genes required for growth in culture and on corn roots. A total of 108 genes were identified as contributing to the fitness of strain PGPR2 on roots. The importance in root colonization of four genes identified in the INSeq screen was verified by constructing deletion mutants in the genes and testing them for the ability to colonize corn roots singly or in competition with the wild type. All four mutants were affected in corn root colonization, displaying 5- to 100-fold reductions in populations in single inoculations, and all were outcompeted by the wild type by almost 100-fold after seven days on corn roots in mixed inoculations of the wild type and mutant. The genes identified in the screen had homology to genes involved in amino acid catabolism, stress adaptation, detoxification, signal transduction, and transport. INSeq technology proved a successful tool to identify fitness factors in P . aeruginosa PGPR2 for root colonization.