Marine Sponge Dendrilla Nigra Research Articles

Revealing the ability of a novel polysaccharide bioflocculant in bioremediation of heavy metals sensed in a Vibrio bioluminescence reporter assay

A bioflocculant-producing bacterial strain, designated MSI021, was isolated from the marine sponge Dendrilla nigra and demonstrated 94% flocculation activity in a kaolin clay suspension. MSI021 was identified as Bacillus cereus based on phylogenetic affiliation and biochemical characteristics. The purified extra-cellular bioflocculant was chemically elucidated as a polysaccharide molecule. The polysaccharide bioflocculant was stable under both acidic and alkaline conditions (pH 2.0–10.0) and temperatures up to 100 °C. The purified bioflocculant efficiently nucleated the formation of silver nanoparticles which showed broad spectrum antibacterial activity. The ability of the bioflocculant to remediate heavy metal toxicity was evaluated by measuring the inhibition of bioluminescence expression in Vibrio harveyi. Enrichment of heavy metals such as zinc, mercury and copper at concentrations of 1, 2 and 3 mM in culture media showed significant reduction of bioluminescence in Vibrio, whereas media enriched with heavy metals and bioflocculant showed dose dependent improvement in the expression of bioluminescence. The assay results demonstrated that the polysaccharide bioflocculant effectively mitigates heavy metal toxicity, thereby improving the expression of bioluminescence in Vibrio. This bioluminescence reporter assay can be developed into a high-throughput format to monitor and evaluate of heavy metal toxicity. The findings of this study revealed that a novel polysaccharide bioflocculant produced by a marine B. cereus demonstrated strong flocculating performance and was effective in nucleating the formation antibacterial silver nanoparticles and removing heavy metals. These results suggest that the MSI021 polysaccharide bioflocculant can be used to develop greener waste water treatment systems.

Antiadhesive activity of poly-hydroxy butyrate biopolymer from a marine Brevibacterium casei MSI04 against shrimp pathogenic vibrios.

BackgroundVibrio pathogens are causative agents of mid-culture outbreaks, and early mortality syndrome and secondary aetiology of most dreadful viral outbreaks in shrimp aquaculture. Among the pathogenic vibrios group, Vibrio alginolyticus and V. harveyi are considered as the most significant ones in the grow-out ponds of giant black tiger shrimp Penaeus monodon in India. Use of antibiotics was banned in many countries due to the emergence of antibiotic-resistant strains and accumulation of residual antibiotics in harvested shrimp. There is an urgent need to consider the use of alternative antibiotics for the control of vibriosis in shrimp aquaculture. Biofilm formation is a pathogenic and/or establishment mechanism of Vibrio spp. This study aims to develop novel safe antibiofilm and/or antiadhesive process using PHB to contain vibrios outbreaks in shrimp aquaculture.ResultsIn this study a poly-hydroxy butyrate (PHB) polymer producing bacterium Brevibacterium casei MSI04 was isolated from a marine sponge Dendrilla nigra and production of PHB was optimized under submerged-fermentation (SmF) conditions. The effect of carbon, nitrogen and mineral sources on PHB production and enhanced production of PHB by response surface methods were demonstrated. The maximum PHB accumulation obtained was 6.74 g/L in the optimized media containing 25 g/L starch as carbon source, 96 h of incubation, 35°C and 3% NaCl. The highest antiadhesive activity upto 96% was recorded against V. vulnificus, and V. fischeri, followed by 92% against V. parahaemolyticus and V. alginolyticus and 88% inhibition was recorded against V. harveyi.ConclusionIn this study, a thermostable biopolymer was chemically characterized as PHB based on 1HNMR spectra, FT-IR and GC-MS spectra. The NMR spectra revealed that the polymer was an isocratic homopolymer and it also confirmed that the compound was PHB. The antiadhesive activity of PHB was determined in microtitre plate assay and an effective concentration (EC) of PHB (200 μl containing 0.6 mg PHB) was confirmed by confocal laser scanning microscopic analysis of vibrio biofilm on pre-treated glass and polystyrene surfaces. This is a first report on anti-adhesive activity of PHB against prominent vibrio pathogens in shrimp aquaculture.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-014-0114-3) contains supplementary material, which is available to authorized users.

Denigrins A–C: new antitubercular 3,4-diarylpyrrole alkaloids from Dendrilla nigra

Chemical diversity is vital to antitubercular drug discovery as it ensures a novel bioactivity profile. Marine sponges have so far provided more than 1000 new bioactive molecules. Ethyl acetate extract of the marine sponge Dendrilla nigra on bioactivity-guided screening yielded three new compounds denigrins A–C, with potent antitubercular activity. Spectral and chemical analyses confirmed that these three compounds belong to the 3,4-diaryl pyrrole alkaloid category. The presence of monohydroxy substitution on benzene rings is not very common in lamellarin and related 3,4-diaryl pyrrole alkaloids isolated from marine invertebrates. Among these, denigrin C showed highest potency (minimum inhibitory concentration 4 μg/mL) against Mycobacterium tuberculosis H37Rv.

Biopotential of secondary metabolites isolated from marine sponge Dendrilla nigra

Objective To evaluate the biopotential activity of secondary metabolites from marine sponge Dendrilla nigra (D. nigra) collected from the Gulf of Mannar. Objective: Soxhlet extraction method was used to extract the secondary metabolites and various assays were carried out. Results D. nigra showed potent antibacterial, antioxidant, anti-inflammatory and anticancer activities and it was also subjected for brine shrimp lethality and cytotoxicity assays. The secondary metabolites were characterized by gas chromatography-mass spectrometry (GC-MS) analysis. Conclusions Based on the present study, it can be inferred that the bioassay guided fractionation and purification of D. nigra may come up with potent bioactive drug.

Optimization and characterization of rhamnolipid biosurfactant from sponge associated marine fungi Aspergillus sp. MSF1

A sponge associated hydrocarbon emulsifying marine fungi Aspergillus sp. MSF1 was isolated from the marine sponge Dendrilla nigra. Production of biosurfactant was confirmed with different screening methods including hemolytic activity, oil displacement test, drop collapsing test, and emulsification index. The production was optimized under submerged fermentation conditions. An enhanced biosurfactant production was achieved with pH 7, 30°C, 2% NaCl, 1% MgCl2, 1% asparagine and glucose and yeast extract as carbon and nitrogen sources, respectively. Among the different media, the Sabouraud's dextrose broth showed the highest emulsification activity. The surface active compound was separated using three step differential solvents fractionation and the active fraction was obtained in diethyl ether. Based on the estimation of macromolecules, TLC, FT-IR and HPLC analysis, the surface active compound was characterized as rhamnolipid. Emulsification activity of the cell free supernatant and different solvent extra...

Biofilm disruption potential of a glycolipid biosurfactant from marineBrevibacterium casei

The antibiofilm activity of a glycolipid biosurfactant isolated from the marine actinobacterium Brevibacterium casei MSA19 was evaluated against pathogenic biofilms in vitro. The isolate B. casei MSA19 was a potential biosurfactant producer among the 57 stable strains isolated from the marine sponge Dendrilla nigra. The biosurfactant production was optimized under submerged fermentation. The purified glycolipid showed a broad spectrum of antimicrobial activity. Based on the minimum inhibitory concentration/minimum bactericidal concentration ratio, the glycolipid was determined as bacteriostatic. The glycolipid biosurfactant disrupted the biofilm formation under dynamic conditions. The disruption of the biofilm by the MSA19 glycolipid was consistent against mixed pathogenic biofilm bacteria. Therefore, the glycolipid biosurfactant can be used as a lead compound for the development of novel antibiofilm agents.

Production of a new glycolipid biosurfactant from marine Nocardiopsis lucentensis MSA04 in solid-state cultivation

Considering the need of potential biosurfactant producers and economic production processes using industrial waste, the present study aims to develop solid-state culture (SSC) of a marine actinobacterium for biosurfactant production. A potential biosurfactant producer Nocardiopsis lucentensis MSA04 was isolated from the marine sponge Dendrilla nigra. Among the substrates screened, wheat bran increased the production significantly ( E 24 25%) followed by oil seed cake and industrial waste such as tannery pretreated sludge, treated molasses (distillery waste) and pretreated molasses. Enhanced biosurfactant production was achieved under SSC conditions using kerosene as carbon source, beef extract as nitrogen source and wheat bran as substrate. The maximum production of biosurfactant by MSA04 occurred at a C/N ratio of 0.5 envisaging that a higher amount of nitrogen source is required by the strain compared to that of the carbon source. The kerosene and beef extract interactively increase the production and a stable production was attained with the influence of both factors independently. A significant interactive influence of secondary control factors such as copper sulfate and inoculum size was validated in response surface methods-based experiments. The surface active compound produced by MSA04 was characterized as glycolipid with a hydrophobic non-polar hydrocarbon chain (nonanoic acid methyl ester) and hydrophilic sugar, 3-acetyl 2,5 dimethyl furan. In conclusion, the strain N. lucentensis MSA04 was a potential source of glycolipid biosurfactant, could be used for the development of bioremediation processes in the marine environment.

Optimization, Purification, and Characterization of Extracellular Mesophilic Alkaline Cellulase from Sponge-Associated Marinobacter sp. MSI032

Marinobacter sp. (MSI032) isolated from the marine sponge Dendrilla nigra was optimized for the production of extracellular cellulolytic enzyme (CMCase) by submerged fermentation. Initial experiments showed that the culture medium containing 1% maltose as carbon source and 1% peptone and casein as nitrogen source supported maximal enzyme production at 27 degrees C and at a pH of 9.0. Further optimization carried out showed the maximal enzyme production was supported by the presence of 2% NaCl and 10 mM Zn(2+) ions in the production media. The production of enzyme cellulase occurred at 48 h of incubation which proved the importance of this strain for cellulase production in large scale. Further, the enzyme was purified to 12.5-fold with a 37% yield and a specific activity of 2,548.75 U/mg. The purified enzyme displayed maximum activity at mesophilic temperature (27-35 degrees C) and at a broad pH range with optimal activity at pH 9.0. The purified enzyme was stable even at a higher alkaline pH of 12.0 which is greater than the pH stability that has not been reported in any of the cellulolytic isolates studied so far. Thus, from the present study, it is crucial that, instead of exploring the thermophilic resource that is limited in natural environments, the mesophilic bacteria that occurs commonly in nature can be added up to the database of cellulolytic bacteria. Thus, it is possible that a wide diversity of mesophilic bacteria associated with marine sponges opens up a new doorstep for the degradation of cellulosic waste material for the production of liquid fuels. This is the first report elucidating the prospects of sponge-associated marine bacterium for the production of extracellular alkaline cellulase.

Optimization and production of novel antimicrobial agents from sponge associated marine actinomycetes Nocardiopsis dassonvillei MAD08

The sponge-associated actinomycetes were isolated from the marine sponge Dendrilla nigra, collected from the southwest coast of India. Eleven actinomycetes were isolated depending upon the heterogeneity and stability in subculturing. Among these, Nocardiopsis dassonvillei MAD08 showed 100% activity against the multidrug resistant pathogens tested. The culture conditions of N. dassonvillei MAD08 was optimized under submerged fermentation conditions for enhanced antimicrobial production. The unique feature of MAD08 includes extracellular amylase, cellulase, lipase, and protease production. These enzymes ultimately increase the scope of optimization using broad range of raw materials which might be efficiently utilized. The extraction of the cell free supernatant with ethyl acetate yielded bioactive crude extract that displayed activity against a panel of pathogens tested. Analysis of the active thin layer chromatography fraction by Fourier transform infrared and gas chromatography-mass spectrometry evidenced 11 compounds with antimicrobial activity. The ammonium sulfate precipitation of the culture supernatant at 80% saturation yielded an anticandidal protein of molecular weight 87.12 kDa. This is the first strain that produces both organic solvent and water soluble antimicrobial compounds. The active extract was non-hemolytic and showed surface active property envisaging its probable role in inhibiting the attachment of pathogens to host tissues, thus, blocking host-pathogen interaction at an earlier stage of pathogenesis.

Culturable heterotrophic bacteria from the marine sponge Dendrilla nigra: isolation and phylogenetic diversity of actinobacteria

Culturable heterotrophic bacterial composition of marine sponge Dendrilla nigra was analysed using different enrichments. Five media compositions including without enrichment (control), enriched with sponge extract, with growth regulator (antibiotics), with autoinducers, and complete enrichment containing sponge extract, antibiotics, and autoinducers were developed. DNA hybridization assay was performed to explore host specific bacteria and ecotypes of culturable sponge-associated bacteria. Enrichment with selective inducers (AHLs and sponge extract) and regulators (antibiotics) considerably enhanced the cultivation potential of sponge-associated bacteria. It was found that Marinobacter (MSI032), Micromonospora (MSI033), Streptomyces (MSI051), and Pseudomonas (MSI057) were sponge-associated obligate symbionts. The present findings envisaged that “Micromonospora–Saccharomonospora–Streptomyces” group was the major culturable actinobacteria in the marine sponge D. nigra. The DNA hybridization assay was a reliable method for the analysis of culturable bacterial community in marine sponges. Based on the culturable community structure, the sponge-associated bacteria can be grouped (ecotypes) as general symbionts, specific symbionts, habitat flora, and antagonists.

Optimization of extracellular psychrophilic alkaline lipase produced by marine Pseudomonas sp. (MSI057)

An endosymbiotic Pseudomonas sp. (MSI057), which could produce high yields of lipase, was isolated from marine sponge Dendrilla nigra, collected from the peninsular coast of India. Maximum production of enzyme was obtained in minimal medium supplemented with 1% tributyrin. Catabolite repression was observed when the medium was supplemented with readily available carbon sources. The optimum temperature and pH for the enzyme production was 30 degrees C and 9.0, respectively. The enzyme exhibited maximum activity in pH range of 8-9 with an optimum pH 9.0. The activity of purified enzyme was optimum at 37 degrees C and showed 80% activity at 20 degrees C and the enzyme activity decreased dramatically above 50 degrees C. Based on the present findings, the enzyme was characterized as psychrophilic alkaline lipase, which can be developed for industrial applications.

Antibacterial potential of antagonistic Streptomyces sp. isolated from marine sponge Dendrilla nigra

The role of Streptomyces sp. (BTL7) in synthesis of antibacterial agents reported from the marine sponge Dendrilla nigra was evaluated. Selective isolation of actinomycetes was performed on the newly developed selective media, Sponge Agar (SA) 1 and SA 2. The growth rate and antibiotic production were increased on the media supplemented with sponge extract. The chosen isolate BTL7 showed inhibitory interaction with Micrococcus luteus and the extracellular products contained potent antibacterial agents. The minimum inhibitory concentration of BTL7 against M. luteus was 44 μg protein/ml and the minimum bactericidal concentration was 88 μg protein/ml. Peak antibacterial activity was observed at 72 h in batch culture. Based on the findings, it could be inferred that bacterial endosymbionts sponges could form a reliable source for bioprospecting of next generation pharmaceutical agents.

Dendrilla nigra, a marine sponge, as potential source of antibacterial substances for managing shrimp diseases

Secondary metabolites of marine sponge Dendrilla nigra were tested for determining the efficacy of controlling shrimp bacterial pathogens. Based on the exploratory experiments, the chosen dose of D. nigra (500 mg/kg of shrimp) was used for pilot experiment. The percent relative protection (PRP) of shrimps treated with Dendrilla feed and challenged with various concentrations of bacterial pathogen was evaluated. Dendrilla feed elicited complete protection (100% survival) against the most common shrimp pathogens such as luminescent Vibrio harveyi and Vibrio alginolyticus. Results of combined bacterial challenge indicated that Dendrilla was a broad spectrum vibriostatic agent. Invariably, the survival of treated shrimp against the bacterial infection was significant at p<0.01 level. Based on the present findings, it could be inferred that the secondary metabolites of D. nigra form an excellent source for developing potent antibacterial agents to combat bacterial diseases of shrimp and replace the conventional antibiotics.