Showing papers by "Rosamma Philip published in 2017"

Marine Algicolous Endophytic Fungi - A Promising Drug Resource of the Era.

Abstract: Endophytic fungi have currently been acknowledged as the most promising source of bioactive compounds for drug discovery, and considerable progress has been made in exploring their diversity, species richness, and bioprospecting. Fungal endophytes from unique environmental settings offer a pool of potentially useful medicinal entities. Owing to the constant stresses imposed on macroalgae by marine environments, it is believed that algae and their associated endophytic symbionts represent a good source of structurally diverse bioactive secondary metabolites. Despite the proven significance of active metabolites of algal endophytes, little have been exploited. This review highlights the latest discoveries in algicolous endophytic research, with particular focus on the bioactive metabolites from algal endophytes. Compounds are classified according to their reported biological activities, like anticancer, antibacterial, antifungal, and antioxidant properties. Present experimental evidence suggests that a majority of the bioactive metabolites were reported from Phaeophyceae followed by Rhodophyceae and Chlorophyceae. An intensive search for newer and more effective bioactive metabolites has generated a treasure trove of publications, and this review partially covers the literature published up to 2016.

Production and characterization of polyhydroxybutyrate from Vibrio harveyi MCCB 284 utilizing glycerol as carbon source.

Abstract: Aim Production and characterization of polyhydroxybutyrate (PHB) from moderately halophilic bacterium Vibrio harveyi MCCB 284 isolated from tunicate Phallusia nigra. Methods and Results Twenty five bacterial isolates were obtained from tunicate samples and three among them exhibited an orange fluorescence in Nile red staining indicating the presence of PHB. One of the isolates, MCCB 284, which showed rapid growth and good polymer yield, was identified as V. harveyi. The optimum conditions of the isolate for the PHB production were pH 8.0, sodium chloride concentration 20 g l−1, inoculum size 0.5% (v/v), glycerol 20 g l−1 and 72 h of incubation at 30°C. Cell dry weight of 3.2 g l−1, PHB content of 2.3g l−1 and final PHB yield of 1.2 g l−1 were achieved. The extracted PHB was characterized by FTIR, NMR and DSC-TGA techniques. Conclusion An isolate of Vibrio harveyi that could effectively utilize glycerol for growth and PHB accumulation was obtained from tunicate Phallusia nigra. PHB produced was up to 72% based on cell dry weight. Significance and impact of the study This is the first report of an isolate of Vibrio harveyi which utilizes glycerol as the sole carbon source for PHB production with high biomass yield. This isolate could be of use as candidate species for commercial PHB production using glycerol as the feed stock or as source of genes for recombinant PHB production or for synthetic biology. This article is protected by copyright. All rights reserved.

Regulating gonad inhibition and vitellogenin/vitellin induction in Penaeus monodon using mature GIH fusion protein and polyclonal antisera.

Abstract: Gonad inhibiting hormone (GIH), type II class of the CHH family neuropeptides, is released by the neurohaemal XO-SG complex of the eyestalk. The inhibitory function of GIH has a pivotal role in gonad development and reproduction. In this study, we report the expression and production of a thioredoxin-fused mature GIH protein (mf-PmGIH) of Penaeus monodon in a bacterial system and its use as antigen to raise polyclonal antiserum (anti-mf-PmGIH). The mature GIH gene of 237bp that codes for 79 amino acids, was cloned into the Escherichia coli thioredoxin gene fusion expression system. The expression vector construct (mf-PmGIH+pEt32a+) upon induction produced 32.16kDa mature GIH fusion protein (mf-PmGIH)·The purified fusion protein was used as exogenous GIH and as antigen to raise polyclonal antisera. The fusion protein when injected into juvenile shrimp significantly reduced vitellogenin/vitellin levels by 31.55% within 72h in comparison to the controls showing the gonad inhibiting property. Vitellogenin/vitellin levels were significantly induced by 74.10% within 6h when polyclonal antiserum (anti-mf-PmGIH - 1:500) was injected in P. monodon. Anti-mf-PmGIH immunolocalized GIH producing neurosecretory cells in the eyestalk of P. monodon. The present manuscript reports an innovative means of gonad inhibition and vitellogenin/vitellin induction with thioredoxin fused GIH and antisera developed.

Evaluation of pyocyanin toxicity in various life stages of Penaeus monodon and in nitrifying bacterial consortia for their safe application in recirculating aquaculture systems (RAS) to abrogate pathogenic vibrios

Abstract: Pyocyanin has recently been recognized as antimicrobial agent in aquaculture industry, an alternative to antibiotics, as it accorded higher level inhibitory effect on aquaculture pathogens. As pyocyanin-induced toxicity is a major concern, this study has been undertaken to evaluate the toxicity of purified pyocyanin and to determine the LC50 value for its safe application in aquaculture. The dose-dependent pyocyanin-induced toxicity was tested on various life stages of P. monodon such as nauplius, zoea, mysis and post-larva as well as on nitrifying bacterial consortia used in aquaculture in order to fix the concentration limits to the animal rearing systems. The study revealed that pyocyanin was a potential inhibitory compound to V. harveyi, bacteriostatic at 5 mg L−1 and bactericidal at 10 mg L−1. The LC50 values of pyocyanin at various life stages of P. monodon were higher than the concentration required to abrogate pathogenic V. harveyi. Moreover, pyocyanin did not inhibit nitrification, specifically of nitrifying bacterial consortia used for activating nitrifying bioreactors, at different salinities, suggesting its potential application in recirculating aquaculture systems to control pathogenic vibrios.

Molecular Characterisation of a Novel Isoform of Hepatic Antimicrobial Peptide, Hepcidin (Le-Hepc), from Leiognathus equulus and Analysis of Its Functional Properties In Silico

Abstract: Hepcidin represents a family of cysteine-rich antimicrobial peptides that are mainly expressed in the liver of living organisms. In this study, we have identified and characterised a novel isoform of hepcidin from the common pony fish, Leiognathus equulus (Le-Hepc). A 261-bp fragment cDNA coding for 86 amino acids was obtained. Homologous analysis showed that Le-Hepc belongs to the hepcidin super family and shares sequence identity with other known fish pre-propeptide hepcidin sequences. The ORF encodes for a 24-amino acid (aa) signal peptide coupled to a 36-aa prodomain followed by a 26-aa mature peptide. The mature peptide region has a calculated molecular weight of 2.73 kDa, a net positive charge of +2 and a theoretical pI of 8.23. Phylogenetic analysis of Le-Hepc showed a strong relationship with other fish hepcidin sequences and clustered into HAMP2 group hepcidins. Secondary structural analysis indicated that Le-Hepc mature peptide contains two antiparallel β-sheets strengthened by four disulphide bonds formed by eight conserved cysteine residues. The physicochemical properties of the peptide and its structural parameters are in agreement with characteristic features of an antimicrobial peptide. This is the first report of an antimicrobial peptide from the common pony fish, L. equulus.

Crustacean hyperglycemic hormone family gene silencing in Penaeus monodon mediated through dsRNA synthesized in vitro from genomic and cDNA

Abstract: S Vrinda1, C Reshmi1, Seena Jose1, P Reynold2, K K Vijayan 2, Rosamma Philip3 and I S Bright Singh1* 1National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Cochin 682 016, India 2Central Marine Fisheries Research Institute, Cochin 682 018, India 3Department of Marine Biology, Microbiology and Biochemistry, Cochin University of Science and Technology Cochin 682 016, India

Longfin snake eel, Pisodonophis cancrivorus (Richardson, 1848), as a potential source of antimicrobial peptides

Abstract: Antimicrobial peptides are small, cationic, amphipathic and evolutionarily conserved molecules of the innate immune system of eukaryotes, which they use to wade off a wide range of microbes. The present study was carried out to evaluate longfin snake eel, pisodonophis cancrivorus as a potential source of antimicrobial peptides. The crude peptide extract was obtained by modified acetic acid-acetone precipitation method and its activity was detected by disc diffusion assay. The crude peptide extract was subjected to solid phase extraction using Sep-pak®C-18 cartridges (Waters, USA). The 40% Sep-pak® fractions eluted was further purified by cation exchange chromatography which yielded 5 fractions. Among the five fractions, Pc40-4 and Pc40-5 exhibited the highest antimicrobial activity and showed inhibition against all tested bacterial strains namely Edwardsiella tarda, Bacillus cereus, Vibrio fluvialis, Vibrio cholera, Aeromonas hydrophila and Staphylococcus aureus. Pc40-3 exhibited remarkable antibacterial activity against the Gram-negative bacteria Aeromonas hydrophila (98%). This is the first report on AMPs from Pisodonophis cancrivorus.