Molecular docking study of bio-inhibitors extracted from marine macro-alga Ulva fasciata against hemolysin protein of luminescence disease-causing Vibrio harveyi.

Shrimp grow-out and hatchery systems are being affected by bacterial disease particularly Vibrios. The use of chemotherapeutic agents in aquaculture practices has to lead to the development of resistance among aquatic bacteria. Thus, health management becomes of major importance in aquaculture. Under this situation, progressing bio-inhibitors from marine resources are most appropriate to be considered against pathogenic bacteria. Molecular docking is an appropriate tool in structural biology and computer-assisted drug design to predict and neutralize a target protein of known diseases. In this study, marine macro-alga Ulva fasciata was aimed at developing inhibitors against luminescence disease-causing pathogenic bacteria Vibrio harveyi. U. fasciata was collected from Thoothukudi, Tamil Nadu, India. Extract of U. fasciata was tested against growth and virulence factors of V. harveyi during Penaeus monodon larviculture. Further U. fasciata extract was subjected to GC-MS analysis to identify the biomolecules. The homology modeling of virulent protein, hemolysin of V. harveyi was designed in this study. Hence, it was aimed for molecular docking against the biomolecules identified from U. fasciata extract. During shrimp larviculture, the extract of U. fasciata (200 µg mL-1) exhibited reduction on Cumulative Percentage of Mortality (32.40%) in postlarvae against challenge of V. harveyi infection. Biomolecule Methyl dehydroabietate had showed highest binding affinity among the compounds was evaluated in molecular docking study. Statistical analysis had revealed significant differences (p < 0.05) in trials. Therefore, it was proved that the bio-inhibitors from U. fasciata will be a better option for controlling luminescence disease-causing V. harveyi in shrimp grow-out practices.

Mitochondrial DNA based diversity studies reveal distinct and substructured populations of pearlspot, Etroplus suratensis (Bloch, 1790) in Indian waters.

Pearlspot (Etroplus suratensis) is one of the most commercially important brackish water fish species widely found along the coastal regions of peninsular India and Sri Lanka. Pearlspot is known for its tender flesh, delectable taste, culinary tourism and highyielding market value. Information on the genetic makeup of stocks/populations is extremely vital as it forms the basis for future genetic studies. For this, we utilized ATPase6/8 genes of mtDNA of pearlspot populations collected from nine different locations ranging from Ratnagiri in Maharashtra state on the west coast to Chilika in Odisha on the east coast. Sequence analyses of these genes revealed 33 polymorphic sites, which include 17 singleton and 16 parsimony informative sites. Pair-wise genetic differentiation study (FST = 0.75) indicated significant (P<0.001) differences among all the pairs of stocks except those from Chilika and Nagayalanka. The spatial analysis of molecular variance (SAMOVA) significantly delineated the population into four groups (FCT = 0.69, P = 0.0001), namely northwest (Ratnagiri and Goa); southwest (Mangalore and lakes at Vembanad, Ashtamudi and Vellayani in Kerala); southeast (Pulicat in Tamil Nadu) and northeast (Chilika in Odisha and Nagayalanka in Andhra Pradesh). The above delineation is supported by clades of the phylogenetic tree and also the clusters of median joining haplotype network. The high haplotype diversity (0.84), low nucleotide diversity (0.003), and negative values of Tajima's D (-1.47) and Fu's Fs statistic (-14.89) are characteristic of populations having recently undergone demographic expansion. Mantel test revealed significant isolation by distance. The study identifies highly delineated structured populations with restricted gene flow. If such a stock is overfished, it is highly unlikely that it would recover through migration. For any future breeding programme in this species, it would be desirable to form a base population which incorporates the genetic material from all the locations so that we get a wide gene pool to select from.

Microsatellite (GT)n polymorphism at 3'UTR of SLC11A1 influences the expression of brucella LPS induced MCP1 mRNA in buffalo peripheral blood mononuclear cells.

A (GT)n microsatellite polymorphism at 3'UTR of SLC11A1(solute carrier family 11A1) is associated with the natural resistance to bovine brucellosis. A pleiotropic effect of SLC11A1 on other candidate genes influencing the host resistance including monocyte chemotactic/chemoattractant protein 1 (MCP1) is also hypothesized. In the present study, we report the cloning and characterization of the complete coding sequence of bubaline (bu) MCP1 and its tissue distribution at the transcript level. The buMCP1 exhibited as high as 99% and >80% of sequence identities with the bovine and other domestic animal species homologues. The buMCP1 mRNA was abundant across the different tissues: most abundant in liver and mammary gland, moderate in ovary, skeletal muscle and testis, and least in uterus. Further, quantitative real-time PCR (RTqPCR) analysis revealed that PBMCs carrying so called resistant GT13 allele produced more MCP1 mRNA endogenously as well as when induced with brucella LPS suggesting the pleiotropic roles of SLC11A1 in conferring resistance against the intracellular pathogens particularly against brucellosis. However, the underlying molecular mechanisms by which 3'UTR SLC11A1 concomitantly increases the production of chemokines like MCP1 are yet to be investigated.