A. P. Lipton

Optimization and characterization of a new lipopeptide biosurfactant produced by marine Brevibacterium aureum MSA13 in solid state culture.

The biosurfactant production of a marine actinobacterium Brevibacterium aureum MSA13 was optimized using industrial and agro-industrial solid waste residues as substrates in solid state culture (SSC). Based on the optimization experiments, the biosurfactant production by MSA13 was increased to threefold over the original isolate under SSC conditions with pre-treated molasses as substrate and olive oil, acrylamide, FeCl(3) and inoculums size as critical control factors. The strain B. aureum MSA13 produced a new lipopeptide biosurfactant with a hydrophobic moiety of octadecanoic acid methyl ester and a peptide part predicted as a short sequence of four amino acids including pro-leu-gly-gly. The biosurfactant produced by the marine actinobacterium MSA13 can be used for the microbially enhanced oil recovery processes in the marine environments.

Biopotentials of secondary metabolites isolated from marine sponges

The secondary metabolites of three sponges collected as bycatch in the fishing nets were explored for biological potencies. The sponge Dendrilla nigraexhibited wider biological activity. It showed potent activity in antibacterial, brineshrimp cytotoxicity, larvicidal, antifouling and ichthyotoxic assays. One of the well-studied cytotoxic sponge Axinella donnaniwas least active in brineshrimp cytotoxicity assay. The secondary metabolites of Clathria gorgonoideswere highly cytotoxic albeit it showed least activity in other bioassays. Based on the present findings, it could be inferred that the bioassay-guided fractionation and purification of D. nigramay come up with potent bioactive drugs. %

Immunomodulatory potential of marine secondary metabolites against bacterial diseases of shrimp

Shrimp disease management using bioactive marine secondary metabolites (MSMs) was developed as a package of practice for the sustainable shrimp farming. Therefore, the effect of MSMs on the host defense factors of shrimp was evaluated in the present study. Findings indicated that Ulva diet significantly increase the defense factors such as haemogram, agglutination index, phagocytic rate, bacterial clearance and serum bactericidal activity of treated shrimps over the control group. Based on the gut bacterial load, Ulva diet was considered as proactive drug whereas Dendrilla diet was determined as a curative agent.

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.

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

Entre as diversas variedades de algas vermelhas, Asparogopsis taxiformis constitui uma das que apresentam alta biomassa na costa de Kollam (Sudoeste da India). No presente estudo A. taxiformis foi coletada, seca e reduzida a po, apos o que foi realizada sua extracao e feito o fracionamento usando-se cromatografia por coluna. As fracoes individuais foram avaliadas in vitro em ensaios para testar sua capacidade anti-incrustante, anticianobacteria e toxicidade para peixes e crustaceos. A fracao extraida com eter de petroleo e etil acetato (2:8) apresentou o espectro de bioatividade mais forte e amplo. No ensaio anti-incrustacao efetuado com com o molusco pulmonado Limnea truncatula, a fracao algal ativa produziu 80% de repelencia do pe em 150 mg/l, enquanto que no ensaio anticianobacteria a fracao ativa inibiu 100% do crescimento de Trichodesmium sp., em 320 mg/l. A fracao algal mostrou o efeito mais intenso contra peixes no nivel de 60 mg/l. Em relacao aos crustaceos, a toxicidade da fracao ativa foi avaliada tambem visando encontrar compostos nao toxicos para organismos nao alvo, tais como Penaeus monodon e Macrobrachium rosembergii. Foi visto que a fracao ativa da coluna mostrou menor toxicidade para estas especies. Os componentes quimicos da fracao ativa foram identificados por meio dos sistemas cromatograficos, tais como TLC, fase reversa do HPLC e GC-MS. O perfil geral de atividade aponta que a fracao ativa da coluna para A. taxiformis pode conter metabolitos bioativos sinergicos que podem ser utilizados para o controle de organismos incrustantes, explosao algal e peixes herbiboros/predadores em tanques de aquicultura.

Biological activity of the red alga Laurencia brandenii

Biological activity of the red alga Laurencia brandenii The marine red alga Laurencia brandenii collected from the southwest coast of India (Indian Ocean) was extracted and fractioned using column chromatography. The individual fractions were evaluated in vitro via antimicrobial activity against six species of Microbial Type Culture Collection and three species of clinical human pathogens, antipest activity on Sitophilus oryzae, maggoticidal activity against 2nd instar larvae of Sarcophaga sp. and termiticidal activity against Microtermes obesi. It was found that the fraction eluted using petroleum ether:chloroform (6:4) exhibited broader biological activities. The phyco-constituents of the active fraction were identified by gas chromatography-mass spectrometry (GC-MS) analysis. The GC-MS profile of the active fraction revealed that the main constituent was octadecadienoic acid (49.75%) followed by n-hexadecanoic acid (14.24%), which might have a functional role in the biological activities. The overall activity profile envisages that these bioactive compounds from L. brandenii could be utilized as a renewable natural resource for the development of novel environmental-compatible formulations for the control of human pathogens, pests, termites and maggots.

Bioactive compounds from Holothuria atra of Indian ocean

The sea cucumber (Holothuria atra) extracts have been evaluated for the presence of bioactive compounds and various biological activities. The methanol extracts showed anti proliferative activities against the Hela and MCF-7 cell lines. Similarly the inhibitory effects of Herpes simplex virus 1 and 2 cells were detected using the plaque reduction assay. The extracts of H. atra were purified using the silica gel column chromatography. The active fractions collected were observed for antimicrobial activity. The GC-MS analysis showed the availability of 59 compounds. The active bioactive compounds found in the H. atra were analyzed and their structure was identified using the 1HNMR and 13C NMR experiments.

Antitumor and antifungal activities of organic extracts of seacucumber Holothuria atra from the southeast coast of India

In phylum Echinodermata, the family Holothuridae is distinguished by its capacity of bioactive compounds. Sea cucumber Holothuria atra is commonly known as the lollyfish. The antifungal activity was detected using agar well diffusion method against the various fungal strains such as Trichoderma viride, Aspergillus niger, Aspergillus flavis, Candida albicans and Penicillium chrysogenum. Relatively high antifungal activity was seen against Candida albicans at 100 μL−1 concentration of extracts. Zone of inhibition was measured at 18 mm of diameter. The anti-tumor activities were detected against the Vero and Hep2 cell lines using MTT assay. The cells were treated with H. atra extract at concentrations 0.078–10mg mL−1. The extract showed high proliferative activity against the Hep2 cells. The body wall extracts of sea cucumber (H. atra) showed effective antifungal and antitumor activities. All these findings suggest that the extracts could be used for the development of drugs.

Effect of Stocking Density on the Survival Rate and Growth Performance in Penaeus monodon

In this study, effect of stocking density and water exchange rate on the survival, growth and apparent feed conversion ratio of Penaeus monodon were evaluated. For that, shrimps were cultured at two different stocking densities such as six and twelve post larvae m− 3 for a period of four months. The experimental ponds were harvested after four months of culture. The results revealed that survival rate of shrimps cultured in low density ponds (LD) was higher (68.4%) whereas a lower rate (51.7%) was observed at high density ponds (HD). In the case of average body weight and length, the shrimps reared at LD experimental ponds were 27.8 g and 18.5 cm respectively. In addition, the average FCR value of shrimps reared at LD ponds was higher (1.8) when compared to the shrimps cultured in HD ponds (2.3). Therefore, stocking density of 6 PL/m 3 is recommend for culturing P. monodon in Kollam coast of India under these experimental conditions.