Optimization and characterization of a new lipopeptide biosurfactant produced by marine Brevibacterium aureum MSA 13 in solid state culture

The biosurfactant production of a marine actinobacterium Brevibacterium aureum MSA 13 was optimized using industrial and agroindustrial solid waste residues as substrates in solid state culture

Bioactivity of the red algae Asparagopsis taxiformis collected from the Southwestern coast of India

Among the diverse variety of red algae, Asparagopsis taxiformis constitutes one of the abundant biomass in the Kollam coast (Southwest coast of India). Therefore, in the present study, A. taxiformis was collected, extracted and fractionated using column chromatography. The individual fractions were evaluated in vitro for their antifouling, anticyanobacterial, piscicidal and crustaceans toxicity assays. The fraction eluted with 2:8, petroleum ether and ethyl acetate exhibited strong and broad spectrum of bioactivity. In antifouling assay against Limnea truncatula, the active algal fraction produced 80% of foot repellency at 150 mg/L whereas in anticyanobacterial assay, the active fraction inhibited 100% growth of Trichodesmium sp. at 320 mg/L. The algal fraction showed higher piscicidal effect at the level of 60 mg/L. The crustacean toxicity of the active fraction was also evaluated to find compounds without toxicity in non target organisms, Penaeus monodon and Macrobrachium rosenbergii. It was found that column fraction showed less toxicity against the non target organisms. The chemical constituents of the active fraction were identified by means of chromatographic systems such as TLC, reverse phase HPLC and GC-MS. The overall activity profile envisages that the active column fraction of A. taxiformis might contain synergistic bioactive metabolites that could be utilized for the control of fouling organisms, algal bloom and herbivorous/predaceous fishes in aquaculture ponds

Micro-algal lethality potentials of marine organisms collected from the Indian littoral

Microalgal lethality bioassay was developed to detect the toxic profile of organic extract of marine organisms and their possible significance in the context of antifouling activities. Organic extracts of seaweeds, Ulva fasciata and Hypnea musciformis, sponges, Dendrilla nigra, Axinella donnai and Clathria gorgonoides and a holothurian Holothuria scabra were used for the detection of microalgal lethality potential. The microalgae such as Isochrysis galbana, Chlorella salina and Nanochloropsis sp. were used for the assay. The findings revealed that H. scabra contained toxic secondary metabolites, which might have the reason for its potent antifouling activity. Invariably all extracts inhibited the growth of microalgae at various concentrations except H. musciformis and A. donnani, which induce the growth of microalgae to certain extent. Based on the present findings, it could be inferred that the ‘microalgal lethality bioassay’ could be used as a primary screening assay system for the detection of biotoxic and antifouling agents from marine organisms

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Not AvailableSponges are closely associated with microorganisms that occur either intracellularly and extracellularly. Sponges are soft-bodied sessile organisms appear to be defenseless in facing predation. Microbial symbionts supposed to have a functional role in the host defense against pathogens, predation and microfouling processes. Recently, the ubiquitous defense enzyme, phospholipase A2 (PLA2) detected in the sponge associated bacterium envisaged the possible functional role in the ecological succession of host sponge against predatory / fouling pressure in the habitat. In present review, we highlighted the possible functional interactions between associated microbes and host sponges and its potentials in bioprospecting approaches.Not Availabl

Sponge-microbial interactions: Ecological implications and bioprospecting avenues

Sponges are closely associated with microorganisms that occur either intracellularly and extracellularly. Sponges are soft-bodied sessile organisms appear to be defenseless in facing predation. Microbial symbionts supposed to have a functional role in the host defense against pathogens, predation and microfouling processes. Recently, the ubiquitous defense enzyme, phospholipase A2 (PLA2) detected in the sponge associated bacterium envisaged the possible functional role in the ecological succession of host sponge against predatory / fouling pressure in the habitat. In present review, we highlighted the possible functional interactions between associated microbes and host sponges and its potentials in bioprospecting approaches

Diversity of a bacterial community associated with Cliona lobata Hancock and Gelliodes pumila (Lendenfeld, 1887) sponges on the South-East coast of India

Abstract Marine sponges are sources of various bioactive metabolites, including several anticancer drugs, produced mainly by sponge-associated microbes. Palk Bay, on the south-east coast of India, is an understudied, highly disturbed reef environment exposed to various anthropogenic and climatic stresses. In recent years, Palk Bay suffered from pollution due to the dumping of untreated domestic sewage, effluents from coastal aquaculture, tourism, salt pans, cultivation of exotic seaweeds, and geogenic heavy-metal pollution, especially arsenic, mercury, cadmium, and lead. Low microbial-abundant sponge species, such as Gelliodes pumila and Cliona lobata, were found to be ubiquitously present in this reef environment. Triplicate samples of each of these sponge species were subjected to Illumina MiSeq sequencing using V3–V4 region-specific primers. In both C. lobata and G. pumila, there was an overwhelming dominance (98 and 99%) of phylum Candidatus Saccharibacteria and Proteobacteria , respectively. The overall number of operational taxonomic units (OTUs) was 68 (40 and 13 OTUs unique to G. pumila and C. lobata, respectively; 15 shared OTUs). Alphaproteobacteria was the most abundant class in both the sponge species. Unclassified species of phylum Candidatus Saccharibacteria from C. lobata and Chelotivorans composti from G. pumila were the most abundant bacterial species. The predominance of Alphaproteobacteria also revealed the occurrence of various xenobiotic-degrading, surfactant-producing bacterial genera in both the sponge species, indirectly indicating the possible polluted reef status of Palk Bay. Studies on sponge microbiomes at various understudied geographical locations might be helpful in predicting the status of reef environments

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Not AvailableThe biosurfactant production of a marine actinobacterium Brevibacterium aureum MSA 13 was optimized using industrial and agroindustrial solid waste residues as substrates in solid state culture.Not Availabl

Antimicrobial potential and seasonality of red algae collected from the southwest coast of India tested against shrimp, human and phytopathogens

Fifteen seaweeds belong to 13 families and 6 orders of the rhodophyta were sampled for one year from April 2007 to March 2008 along the southwest coast of India (Indian Ocean). The species were examined for in vitro antimicrobial activity against six pathogenic Vibrio strains isolated from moribund tiger shrimp (Penaeus monodon), six type cultures (Microbial Type Culture Collection, MTCC) of prominent shrimp Vibrio pathogens, 10 multidrug resistant clinical pathogens, four species of Candida obtained from pulmonary TB patients and four species of plant pathogenic fungi to evaluate their potency to be used as natural antibiotics in pharmaceutical and agriculture field. Bioactivity was analyzed from crude extract of fresh and dried samples prepared from different polar and nonpolar solvents. Of these, four species of red algae (Asparagopsis taxiformis, Laurencia ceylanica, Laurencia brandenii, Hypnea valentiae) were found to be highly active. Broadest and highest activity was observed in the crude extract of A. taxiformis. Among the pathogens tested, shrimp pathogenic Vibrios were the most susceptible organisms while phytopathogens were found to be little resistant. In the present study, methanol was found to be the best solvent for extracting antimicrobial metabolites from dried samples rather than fresh. Seasonal variation in the antimicrobial activity was observed with higher level of activity recorded from A. taxiformis between December and January. The active principle of A. taxiformis was purified in column chromatography, TLC and reverse phase HPLC. The individual HPLC peaks were subsequently tested against a panel of pathogenic microorganisms and the active constituent was identi- fied by GC-MS. The antimicrobial profile of A. taxiformis suggested that lipophilic compound which was primarily composed of pyrrole-2-carboxylic acid, pentadecanoic acid and octadecanoic acid might have functional role in the chemical defence against microbial invasion and these compounds could be utilized for the development of medically potential products