Seaweeds of the intertidal regions are a rich source of surface associated bacteria and are potential source of antimicrobial molecules. In the present study, 77 epiphytic isolates from eight different algae collected from Little Andaman were enumerated. On testing for their antimicrobial activities against certain pathogens twelve isolates showed positive and six of them showed significant antimicrobial inhibition zone against Shigella boydii type 1, Shigella flexneri type 2a, Shigella dysenteriae type 5, Enterotoxigenic Escherichia coli O115, Enteropathogenic E. coli serotype O114, Vibrio cholera; O1 Ogawa, Aeromonas hydrophila, Klebsiella pneumoniae, Staphylococcus aureus. Based on the activity these six isolates (G1C, G2C, G3C, UK, UVAD, and Tor1) were identified by 16S rRNA gene sequence and were found to belong to the phyla Firmicutes and Proteobacteria. Purified antimicrobial compounds obtained from these isolates were identified by GC-MS. Furan derivatives were identified from G2C Pseudomonas stutzeri KJ849834, UVAD Alcanivorax dieselolei KJ849833, UK Vibrio sp. KJ849837, Tor1 Exiguobacterium profundum KJ849838. While 2-Pyrrolidinone, Phenol, 2, 4-bis (1, 1-dimethylethyl) were from G3C Vibrio owensii KJ849836 and (1-Allylcyclopropyl) methanol from the extracts of G1C Bacillus sp. KJ849835. The results of the present study shows that these six potent isolates isolated from the seaweeds are found to be a source of antimicrobial compounds.

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Titanium-6 aluminium-4 vanadium (Ti64) alloy was modified to a hydrophilic, cytocompatible, antibacterial and bioactive surface via a simple cost effective chemical treatment method. A fine porous network structure of sodium hydrogen titanate (SHT) was formed on the Ti64 alloy surface by using sodium hydroxide treatment. The incorporated Na + ions are replaced by Ag + ions by a subsequent silver nitrate treatment. Contact angle measurement indicated that the silver containing Ti64 alloy surface is hydrophilic at lower silver concentration. The antibacterial study of the thus prepared sample against Staphylococcus aureus confirmed the bacterial resistance of the Ti64 alloy. As evident from the AAS result, the sustained release of Ag into the culture medium results in antibacterial activity. Cytocompatibility studies on MG63 cell lines showed above 80% cell viability and also good cell attachment. This confirmed the nontoxic behavior of the present optimized silver concentration on the Ti64 surface for MG63 cells. In vitro bioactivity of the silver containing Ti64 sample in simulated body fluid showed bone-like apatite formation and the apatite-forming ability is not affected by Ag concentration or by heat treatment. Taken together, this surface modification study adds further information to our knowledge on the development of a bioactive Ti64 alloy with hydrophilicity, antibacterial activity and biocompatibility that may have considerable potential application as orthopedic and dental implants.

Ionic liquid induced phase tuned TiO2 nanoparticles for ammonia gas sensing.

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The marine microbiome is a complex and least-understood habitat, which play a significant role in global biogeochemical cycles. The present study reported the culture-independent assessment of microbial diversity from the Arabian Sea (AS) sediments (from Gujarat to Malabar; at 30 m depth) by using metagenome sequence analysis. Our results elucidated that bacterial communities in the Malabar coastal region are highly diverse than the Gujarat coast. Moreover, Statistical analysis (Spearman rank correlation) showed a significant correlation co-efficient value (r = P < 0.001) between microbial communities and physicochemical parameters (salinity and dissolved oxygen) in the water column. A total of 39 bacterial phyla were recorded from the eastern side of AS, of which six phyla Proteobacteria, Bacteroidetes , Actinobacteria, Cyanobacteria, Firmicutes, and Planctomycetes were found to be the most dominant group. The most dominant genus from Valapad region (Malabar Coast) was found to be Halomonas sp., while other regions were dominated with Psychrobacter pulmonis . The subsequent Principal Coordinate Analysis (PCoA) showed 99.53% variance, which suggests that, highly distinct microbial communities at Valapad (Malabar Coast) sampling location than other sites. Moreover, the microbial metabolic activity analysis revealed the important functions of microbial communities in the AS are hydrocarbon degradation, polymer degradation, nutrient oxidation and sulphate reduction (biodegradation process). Further extended studies are needed to be carried out for better understanding the functional diversity of microbial communities from the marine sediments.

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