Impacts of climate variability and resulting changes in aquatic ecosystems have caused a rapid shift in the spatial distribution of species. This shift forces diversification in livelihood options among the fishers. Many resources are emerging as new fishery which could be the indicator of changes in the food web and ecosystems as a whole due to climatic variability coupled with changes in exploitation patterns. One of the emerging non-conventional fishery resources is the pufferfish which is exploited along the Karnataka coast, south-eastern Arabian Sea. A decrease in mean trophic level due to the increased fishing effort or climatic variability resulted in the removal of top-level predators leading to the rise of mid-level carnivores like Lagocephalus inermis in the Arabian Sea. A substantial increase has been noticed in the landing of pufferfish in trawl along with Karnataka since 2007 and has resulted in diversification of the employment in the fisheries sector. The pufferfish brought to the shore by trawlers are degutted, de-skinned, and cut into small pieces, and packed for transportation to other parts of the country. This sector has provided employment to about fifty women in each landing center, and each of them earns INR 200-300/day. The matured eggs collected from the fish are sold at a price of INR 10/kg. In addition, the trade of salted and dried fishes generated employment to an additional 50 women in the sector. This diversification has given more employment opportunities, especially to women. The study conducted revealed an increase of 1.5 fold from landing to the final product. Diversification of the livelihood to cope up with the changes in the fishery is an adaptation measure to combat species shift associated with climate change and climatic variability.
The present study on the biology of Sardinella longiceps was carried out at the Veraval coast of Gujarat. The observed length of species was in the range of 145 to 236 mm and weighing from 37.54 to 122.35 gm. The highest mean length of 206 ± 9 mm was observed in the month of December.
A heterotrophoic Bacillus amyloliquefaciens MTCC12713 isolated from an intertidal macroalga Kappaphycus alverezii displayed promising antibacterial activities against multidrug-resistant bacteria. Genome mining of the bacterium predicted biosynthetic gene clusters coding for antibacterial secondary metabolites. Twenty-one membered macrocyclic lactones, identified as difficidin analogues bearing 6-hydroxy-8-propyl carboxylate, 9-methyl-19-propyl dicarboxylate, 6-methyl-9-propyl dicarboxylate-19-propanone, and (20-acetyl)-6-methyl-9-isopentyl dicarboxylate (compounds 1 through 4) functionalities were purified through bioassay-guided fractionation. The difficidin analogues exhibited bactericidal activities against vancomycin-resistant Enterococcus faecalis, methicillin-resistant Staphylococcus aureus, and other drug-resistant strains, such of Klebsiella pneumonia and Pseudomonas aeruginosa with the minimum inhibitory concentration of about 2–9 × 10?3 ?M. A plausible enzyme-catalyzed biosynthetic pathway that is generated through addition of acrylyl initiator unit by repetitive decarboxylative Claisen condensation modules with malonate units was recognized, and their structures were corroborated with gene organization of the dif operon, which could comprehend dif A-O (~ 70 kb). Drug-likeness score for 5-ethoxy-28-methyl-(9-methyl-19-propyl dicarboxylate) difficidin (compound 2, 0.35) was greater than those of other difficidin analogues, which corroborated the potential in vitro antibacterial properties of the former. The present study demonstrated the potential of difficidin analogues for pharmaceutical and biotechnological uses against the bottleneck of emergent drug-resistant pathogens.
An undescribed tricyclic spiroketal compound clathriketal was purified from the solvent extract of the Microcionidae sponge Clathria prolifera, and was characterised as 7-(hydroxymethyl)-13-methoxy-3,11-dimethyl-4-oxo-octahydrospiro[chromene-9,13-pyran]-11-yl propionate by spectroscopic experiments. Clathriketal exhibited significant anti-hyperglycemic property by attenuating serine protease dipeptidyl peptidase-IV (IC50 0.37?mM), and its activity was comparable with the standard diprotin A (IC50 0.31?mM). The spiroketal also exhibited significant inhibitory potentials against carbolytic enzymes ?-glucosidase (IC50 0.43?mM) and ?-amylase (IC50 0.41?mM). Superior antioxidant properties of clathriketal against the oxidants, 2, 2?-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid and 2, 2-diphenyl-1-picrylhydrazyl (IC50 ?1.2?mM) also reinforced its promising anti-hyperglycemic activity. Considerably greater topological surface area (91.29) coupled with lesser steric parameters of clathriketal, as elucidated from the structure-activity relationship analyses could further ascribe the improved ligand-receptor interactions resulting in its prospective anti-hyperglycemic activity. Molecular docking analysis of clathriketal with dipeptidyl peptidase-IV recorded lesser binding energy (–9.63?kcal/mol), which further corroborated its prospective antihyperglycemic activity.
Four biogenic Beta sitosterol analogues were identified from methanolic extract of the leaves of loop root mangrove Rhizophora mucronata. Molecular docking simulations were carried out in the active sites of 5lipoxygenase/cyclooxygenase2, and the docking scores and binding energies of the studied Beta-sitosterol analogues were positively correlated with their attenuation properties against 5lipoxygenase and cyclooxygenase2.
The food and feeding habits of the sawtooth barracuda, Sphyraena putnamae, from the southeastern Arabian Sea, India, were studied from 1367 specimens having a fork length range of 16.5–76 cm. The sawtooth barracuda consumed diverse prey items, which were grouped into three categories: teleosts, molluscs, and crustaceans. Teleosts were the preferred and dominant food component, while molluscs and crustaceans constituted the secondary and accessory food items, respectively. The chief constituents of the teleost group on basis of their dominance were identified to be carangids, scombrids, engraulids, leiognathids, and synodontids. The empty stomach ratio and stomach fullness index did not differ significantly between the sexes. The juveniles of both sexes exhibited a significantly higher stomach fullness index compared with the adults. A clear ontogenetic shift in the feeding pattern was observed, with only the crustaceans forming the diet in lower size class (<20 cm) being gradually replaced by molluscs and teleosts by medium-sized fishes (30–60 cm) and teleosts alone in the gut of S. putnamae above 65 cm. This study provides essential baseline information on the feeding habits of the Sphyraena putnamae, the first of its kind in the region. The study will be useful in understanding the trophodynamics of the species for proposing suitable management and conservation measures.