Antifouling activity of alkaline protease from halotolerant Bacillus sp. isolated from marine source

1274-1279In this study, an attempt has been made to explore the antifouling activity of the marine halotolerant bacterium, namely, Bacillus sp. About 10 different bacteria were isolated using the Zobell marine agar medium from the marine sediment samples that were collected from the Marina beach, Bay of Bengal, India. The growth pattern tests of the 10 bacteria were documented. Among the 10 different isolates, two exhibited the protease activity in skim milk agar. The antifouling activity was further tested against five different fouling bacteria. The antifouling activity of alkaline protease isolated from Bacillus sp. inferred that it exhibited pronounced inhibitory zones against fouling bacterial strains with least minimal inhibitory concentration range between 25 and 100 units/mg protein. Anticrustacean assay was performed using Artemia salina of alkaline protease, which showed good activity. The results suggest that Bacillus sp. produced an extracellular alkaline protease, which was responsible for the antifouling and algicidal activity of marine fouling organisms. This study tends to indicate that Bacillus sp. could be further explored for the development of new antifouling agents

Characterization and identification of isolated bacteria from ice-ice disease infected seaweed Kappaphycus alvarezii

1286-1290Ice-ice disease occurs in cultivated algal seaweed Kappaphycus alvarezii due to pathogenic bacterial infections. This seaweed has rich source of carrageenan widely known as the kappa carrageenan. Generally, ice-ice disease leads to whitening of the branches initiated with colour changes of the thalli, which become transparent in the end. This study was aimed to isolate and identify the bacteria based on morphology and biochemical characterization on ice-ice diseased K. alvarezii from three different places, namely, Kottapatinam, Thondi and Rameswaram. The bacterium was isolated in Zobell Marine Agar (ZMA) and thiosulfate-citrate-bile saltsucrose (TCBS) agar. Morphological and biochemical characterizations revealed that the isolated bacteria causing ice-ice disease were closely related to the genera Bacillus in ZMA and Vibrio species in TCBS. Total viability count, physical and chemical properties of the bacteria by gram staining and morphological analysis were done for all species isolated from three places

Enhancement of bacteriorhodopsin production from novel haloarchaea strains of Marakanam region of Tamil Nadu

Haloarchaea from high saline habitats are known to contain industrially important value-added bioactive compounds such as bacteriorhodopsin, carotenoids, lipids, and proteins. The diversity of Haloarchaea from geographically less explored saline habitats has received less attention. In this study isolation and characterization of the biotechnological potential of novel haloarchaea strains from solar saltern, a hypersaline environment in Marakanam, Tamilnadu was carried out. The samples were collected during the pre-monsoon (July) and post-monsoon (January) season and ten different haloarchaea strains were isolated. UV-Vis spectroscopy analysis revealed the bacteriorhodopsin production by all the isolated strains. Further experiments were carried out to estimate the yield of bacteriorhodopsin and to assess their photocurrent activity and biosensor applications. The maximum yield of bacteriorhodopsin was 5.6 mg/L of cultured lysate. This study will contribute to a better understanding on effect of elicitors on bacteriorhodopsin producing different haloarchaea strains and growing knowledge on their biotechnological applications

Phenotypic characterization and 16S rDNA identification of culturable non-obligate halophilic bacterial communities from a hypersaline lake, La Sal del Rey, in extreme South Texas (USA)

Background: La Sal del Rey ( the King’s Salt”) is one of several naturally-occurring salt lakes in Hidalgo County, Texas and is part of the Lower Rio Grande Valley National Wildlife Refuge. The research objective was to isolate and characterize halophilic microorganisms from La Sal del Rey. Water samples were collected from the lake and a small creek that feeds into the lake. Soil samples were collected from land adjacent to the water sample locations. Sample salinity was determined using a refractometer. Samples were diluted and cultured on a synthetic saline medium to grow halophilic bacteria. The density of halophiles was estimated by viable plate counts. A collection of isolates was selected, gram-stained, tested for catalase, and characterized using API 20E® test strips. Isolates were putatively identified by sequencing the 16S rDNA. Carbon source utilization by the microbial community from each sample site was examined using EcoPlate™ assays and the carbon utilization total activity of the community was determined. Results: Results showed that salinity ranged from 4 parts per thousand (ppt) at the lake water source to 420 ppt in water samples taken just along the lake shore. The density of halophilic bacteria in water samples ranged from 1.2 × 102 - 5.2 × 103 colony forming units per ml (cfu ml-1) whereas the density in soil samples ranged from 4.0 × 105 - 2.5 × 106 colony forming units per gram (cfu g-1). In general, as salinity increased the density of the bacterial community decreased. Microbial communities from water and soil samples were able to utilize 12 - 31 carbon substrates. The greatest number of substrates utilized was by water-borne communities compared to soil-based communities, especially at lower salinities. The majority of bacteria isolated were gram-negative, catalase-positive, rods. Biochemical profiles constructed from API 20E® test strips showed that bacterial isolates from low-salinity water samples (4 ppt) showed the greatest phenotypic diversity with regards to the types and number of positive tests from the strip. Isolates taken from water samples at the highest salinity (420 ppt) tended to be less diverse and have only a limited number of positive tests. Sequencing of 16S DNA displayed the presence of members of bacterial genera Bacillus, Halomonas, Pseudomonas, Exiguobacterium and others. The genus Bacillus was most commonly identified. None of the isolates were members of the Archaea probably due to dilution of salts in the samples. Conclusions: The La Sal del Rey ecosystem supports a robust and diverse bacterial community despite the high salinity of the lake and soil. However, salinity does appear to a limiting factor with

Identification of the traditional and non-traditional sulfate-reducing bacteria associated with corroded ship hull

Pitting corrosion due to microbial activity is the most severe type of corrosion that occurs in ship hull. Since biogenic sulfide produced by sulfate-reducing bacteria (SRB) is involved in the acceleration of pitting corrosion of marine vessels, so it is important to collect information about SRB community involved in maritime vessel failure. We investigated the SRB community on corroded hull portion of the ship. With the use of common cultural method and 16S rDNA sequencing, ten bacteria with sulfate reduction ability were isolated and identified. They belonged to both traditional (Desulfovibrio, Desulfotomaculum) and non-traditional (Citrobacter) sulfate-reducing bacteria. All the isolates were able to produce a high amount of sulfide. However, only traditional isolates were showing the amplification for the SRB-specific gene, dsrAB. Further studies on corrosion potential of these two groups of bacteria showed that in spite of high sulfide and biofilm production by non-traditional SRB, they are less aggressive towards the mild steel compare to the traditional group

Anti cancer activity prediction of secondary metabolites from marine sponge discodermia<i style="mso-bidi-font-style:normal"> calyx</i><span style="mso-bidi-font-style:italic">:<i style="mso-bidi-font-style: normal"> </i>An <i style="mso-bidi-font-style:normal">in silico</i> approach </span>

653-658A molecular docking analysis was carried out followed by Molecular Dynamics (MD) simulation studies on the secondary metabolites from a marine sponge Discodermia calyx in order to identify their bioactive targets acting towards cancer. Over expression of Epidermal Growth Factor Receptor (EGFR) results in triple negative breast cancer. Hence, a docking investigation was carried out in order to predict the anticancer properties of secondary metabolites from a marine sponge D. calyx targeting the EGFR. The compounds were further subjected to MD simulation analysis. Docking analysis reveals that the compounds debromohamacanthin B, tetrahydrofurospongin and deoxytopsentin showed good interaction with the EGFR receptor forming hydrogen bonds with the tyrosine and arginine residue preventing the binding of EGF to the EGFR receptor by inhibiting dimerization with a score of 130.13, 139.369 and 114.416 respectively

Studies on the genomic DNA integrity of marine fishes through chip-based gel electrophoresis

1695-1698Present study consists the extraction of gDNA from marine fish gut samples that belong to the Chaetodontidae family. Eppendorf BioSpectrometer kinetic, based on UV spectroscopy, and Qubit 2.0, was employed for this purpose, with ladder. Thus on-chip, gel electrophoresis was performed for the analysis of gDNA quantification and sizing in the NGS sample preparation workflow. Quantification of 2 different gDNAs from gut samples of Pakistan butterfly (Chaetodon collare) and Indian vagabond (Chaetodon decussates) was made with a standard DNA

Virtual Screening of Marine Natural Antifoulant: In Silico Approach to Screen Antifouling Metabolites from Marine Sponges

1042-1048A molecular docking analysis was carried out followed by Molecular Dynamics (MD) simulation studies on the metabolites from various marine sponges in order to identify their metabolites being potent inhibitors towards biofouling. The docking analysis reveals that the metabolites from a marine sponge Acanthodendrilla sp. and Agelas cf. mauritiana may act as potent antifouling agents with the docking scores ranging from 68 to 123 for the metabolites. Chemical structure of the most active ligand was converted into a feature-shaped query. This query was used to align molecules to generate statistically valid lead compound

Facile Solvothermal Preparation of Monodisperse Gold Nanoparticles and Their Engineered Assembly of Ferritin–Gold Nanoclusters

Herein, we report a quick and simple synthesis of water-soluble gold nanoparticles using a HAuCl4 and oleylamine mixture. Oleylamine serves as a reduction agent as well as a stabilizer for nanoparticle surfaces. The particle sizes can be adjusted by modulating reaction temperature and time. Solvothermal reduction of HAuCl4 with oleylamine can be confirmed by measuring the product in Fourier transform infrared (FTIR) spectroscopy. The plasmon band shifting from yellow to red confirms a nanosized particle formation. Amide bonds on the surface of the nanoparticles formed hydrogen bonds with one another, resulting in a hydrophobic monolayer. Particles dispersed well in nonpolar organic solvents, such as in hexane or toluene, by brief sonication. Next, we demonstrated the transfer of gold nanoparticles into water by lipid capsulation using 1-myristoyl-2-hydroxy-sn-glycero-3-phosphocholine (MHPC), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-(methoxy polyethylene glycol)-2000 (DPPE-PEG2k), and 1,2-dioleoyl-sn-glycero-3-N-{5-amino-1-carboxypentyl}iminodiacetic acid succinyl nickel salt [DGS-NTA(Ni)]. The particle concentration can be obtained using an absorbance in ultraviolet–visible (UV–vis) spectra (at 420 nm). Instrumental analyses using transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) analysis, dynamic light scattering (DLS), and FTIR confirmed successful production of gold nanoparticles and fair solubility in water. Prepared gold particles were selectively clustered via engineered ferritin nanocages that provide multiple conjugation moieties. A total of 5–6 gold nanoparticles were clustered on a single ferritin nanocage confirmed in TEM. Reported solvothermal synthesis and preparation of gold nanoclusters may serve as an efficient, alternate way of preparing water-soluble gold nanoparticles, which can be used in a wide variety of biomedical applications