AIMS: Microbiological, biotechnological and chemical characterization of a previously undescribed aryl-crowned polyketide from Bacillus subtilis MTCC 10403 isolated from brown seaweed Anthophycus longifolius with activity against opportunistic Gram-negative food-borne pathogenic bacterial strains. METHODS AND RESULTS: A culture-dependent method was used to isolate heterotrophic B. subtilis associated with A. longifolius and assessed for its antimicrobial properties. Minimum inhibitory concentration (MIC) of the title compound against the test pathogens was analysed by microtube dilution coupled with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide-based colorimetric endpoint detection. Bacillus subtilis MTCC 10403 was found to be antagonistic against Gram-negative food-borne pathogenic Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Salmonella enterica serotype Typhi, Aeromonas hydrophila and Vibrio sp. (diameter of zone of growth inhibition 13-22 mm). Bacillus subtilis was assessed for the presence of secondary metabolite coding polyketide synthase (pks) gene (KC589397, 700-bp gene product) and carboxylate siderophore framework in the aryl-crowned polyketide designated as 7-O-6-(2-acetylphenyl)-5-hydroxyhexanoate-macrolactin by exhaustive spectroscopic techniques. The MIC assay showed that the reference antibiotics tetracycline and ampicillin were active at 25 μg ml-1 against the test pathogens, whereas the newly isolated polyketide displayed anti-infective properties against E. coli, A. hydrophilla, P. aeruginosa and Vibrio sp. at a lower concentration (MIC
Marcias anthias, Pseudanthias marcia Randall and Hoover, 1993, belonging to the subfamily Anthiinae (family: Serranidae) is a highly sought after marine ornamental fish mainly due to its vibrant pink shade. The present study reports the first successful captive brood stock development, spawning, and larval rearing of P. marcia. Brood stock was developed in a 5-ton recirculation aquaculture system (RAS) using 12 wild caught juveniles. After 6 months of rearing, the fish (8–9.5 cm size) started courtship behavior. Spawning occurred at 1900 to 2100 h. The eggs (mean size - 617.9 ± 14.9 μ) were transparent, pelagic, non-adhesive and with single oil globule. The eggs hatched out after an incubation period of about 14–16 h at a water temperature of 29 °C. Newly hatched larvae measured 1206.6 ± 100.02 μ in total average length and increased to 1852.9 ± 24.68 μ at 48 h post hatch (ph). Mouth opened at 48–50 h post hatch (ph) and measured 76 to 80 μ. Larval rearing trials were conducted using rotifer (L and S type), wild zooplankton, copepod nauplii, artemia nauplii and microparticulate diet. Primordial fin development started by the 10th day post-hatching (dph) (larval size ~2.9 mm) while the opercular and dorsal spines were fully formed by 15 dph (total length of the larva was 4.4 mm). Larvae metamorphosed to miniature adult shape by 32–34 dph and on 50 dph they reached the pink colored juvenile stage (42–43 mm) and at this stage, they were transferred to nursery rearing tank. Four treatments with different feed combination were tried and treatment III with wild copepod gave an average survival of 5.2 ± 1.07% and treatment IV with Parvocalanus crassirostris gave an average survival of 7.3 (±2.51) %.
India, a land of distinct climatic and geographic zones, supports a remarkable diversity of avian fauna within both its mainland and its seas. There are over 1200 species of birds recorded in India, with the majority occurring in the mainland (Praveen et al., 2016). Surrounded by extensive marine zones on its three sides, territorial waters and marginal seas around India form seamless habitats for a significant number of marine avian species. Seventy species of marine birds are observed in the region (BirdLife International 2015). These include predominantly open oceanic species like frigate birds, tropicbirds, shearwaters and petrels which are winter visitors or vagrants, but birds like gulls and terns are more commonly found along the coastal waters of India.
Indian squid, Uroteuthis (Photololigo) duvaucelii (Loliginidae) constitute an important component of the inshore cephalopod fisheries along the eastern Arabian Sea. Local environmental variation plays an important role in species–environment interactions in neritic squids, which inhabit nearshore/coastal waters. Such ‘active’ and ‘passive’ responses of squids to environmental changes is crucial in understanding their relationships and influence on the biological processes, distribution and abundance of the fast-growing shortlived coastal loliginids. The empirical relationship between squid abundance and the variability in rainfall and sea surface temperature (SST) were explored in a tropical monsoon fishery. Monthly catch rates (catch per fishing hour) of squids in commercial trawl during 1987–2009 were used as the abundance index. Linear regression models with ARIMA errors were fitted with catch per unit hour time series as dependent variable and rainfall and SST as exogenous variables. While rainfall was observed to have a negative effect on squid abundance, the SST recorded a positive impact. ARIMA models provided satisfactory fit to observed data and forecast of 22 months. Given that the squid life-cycle is a function of their environment, this result is relevant in forecasting squid biomass for themanagement of tropical monsoon fisheries.
Experimental trawl survey cruises covering twelve stations around Lakshadweep archipelago, in southeastern Arabian Sea, caught eleven individuals of the uncommon squid, Histioteuthis miranda. This is the first record from waters around India. These specimens were caught in midwater trawl net operated from research vessel BFV Silver Pompano^ at a depth of 200 m during night. Detailed morphometric and meristic measurements and molecular taxonomic studies confirmed the species identity. Assuming daily deposition of statolith rings, analysis of increments revealed that the species had slow growth reaching 24 mm dorsal mantle length (DML) at the age of 83 days with an average daily growth rate of 0.28 mm DML/day. A juvenile specimen with 13 mm DML had 68 increments with growth rate of 0.19 mm DML/day. Aberrant microstructure (additional nucleus and rings) were found in the statolith of a 24 mm DML specimen.
Coastal waters are optically diverse; studying their optical characteristics is an important application of satellite oceanography. In coastal ecosystems of the northern Indian Ocean, optical diversity has been little studied, except for the global analysis by Mélin and Vantrepotte (2015). This paper is a contribution toward identification and characterization of optical classes in the coastal regions of the northern Indian Ocean. The study identified eight optical classes using the monthly climatological datasets of remote sensing reflectance for the 1998–2013 period from the Ocean Color Climate Change Initiative (OC-CCI, www.oceancolour.org). The optical classification we adopted uses the fuzzy logic method, based on Moore et al. (2009). The seasonal variations of the eight resultant optical classes of the coastal waters of the northern Indian Ocean were explored. From the mean reflectance spectral signals obtained, it appears that classes 1–6 belong to Case-1 waters and classes 7 and 8 correspond to Case-2 waters. Classes 1 to 2 appear in deeper oligotrophic waters; classes 3–6 are present in intermediate depths; classes 7 and 8 are mostly found within inshore eutrophic regions with high chlorophyll concentrations, sediments from river plumes and land runoffs. The optical variability between seasons (the summer and winter monsoon and the intermonsoon seasons) are influenced by variations in physical forcing, such as surface winds, ocean currents, precipitation, and sediment influx from rivers and land runoff. Optical diversity index ranged from around 0.3 to 1.36. High diversity indices ranging between 1 and 1.36 were found in areas dominated by classes 1–4, whereas low diversity indices 0.3 occurred in areas where classes 7 and 8 dominated. The variations in the dominant optical classes are shown to be related to changes in chlorophyll concentration and suspended sediment load, as indicated by remote sensing reflectance at 670 nm. On the other hand, optical diversity appears to be high in zones of transition between dominant optical classes.