Differential expression of akirin gene in black tiger shrimp Penaeus monodon in response to immunostimulant administration and infections with Vibrio harveyi and white spot syndrome virus

The akirin gene, which is strictly localized in the nucleus, plays a critical role in regulating antimicrobial peptide transcription, and has parallel functions to NF-kappa B signaling pathway in both vertebrates and invertebrates. In shrimp, the akirin gene is expressed as innate immunity in response to microbial infection. In the present study, expression of akirin gene in Penaeus monodon with respect to Vibrio harveyi and white spot syndrome virus (WSSV) infections and immunostimulant (beta-glucan) administration were investigated by quantitative polymerase chain reaction. The gene was expressed in various tissue samples of healthy shrimp. Maximum level of expression was immediately after V. harveyi infection, suggesting that it may be an early response gene. Gene expression was remarkably upregulated in the lymphoid organ, gill, and hepatopancreas, whereas downregulation was observed in hemocytes compared with the control. In the case of WSSV-infected samples, the akirin gene was significantly downregulated in the lymphoid organ but there was no significant difference in expression pattern in hemocytes compared to the control. In gill tissue, maximum expression was observed after 2 hr of infection, the same in hepatopancreas. Experimental challenge of beta-glucan fed shrimp infected with V. harveyi and WSSV resulted in significant upregulation of akirin gene expression in lymphoid and gill tissue

Effect of Total Dissolved Solids and Temperature on Bacteriophage Therapy against Luminous vibriosis in Shrimp

Bacteriophage therapy is an efficient, eco-friendly, and scientifically demonstrable solution to antibiotic resistance in bacteria. Environmental factors have a profound influence on the growth and activity of phages. We evaluated the influence of two important parameters of the aquatic environment on phage activity, i.e., total dissolved solids (TDS) and temperature. Evaluated levels of TDS were 11.25, 22.63, and 38.43 mg/ml; studied temperatures were 20, 30, and 37ºC. Levels were chosen from the ranges of values encountered during larvae rearing in a hatchery. Of seve

Broad Spectrum Anti-Bacterial Activity of a Recombinant Phosphatase-Like Protein (rPLP), Isolated from the Shrimp Penaeus monodon

Antimicrobial peptides play a significant role in the innate immune response of crustaceans. The gene coding for a phosphatase-like protein (PLP) from the black tiger shrimp, Penaeus monodon was cloned using pQE-30-UA expression vector and expressed in Escherichia coli M15 host cells. The recombinant protein purified by nickel-nitrilotriacetic acid affinity chromatography, gave a single distinct band of approximately 25 kDa by 15% sodium dodecyl sulfate polyacrylamide gel electrophoresis. The anti-bacterial activity of the recombinant phosphatase-like protein (rPLP) was characterized in vitro. Solid phase agar based assay revealed its inhibitory effect against several gram positive and gram negative bacteria. The minimal inhibitory concentration of the rPLP against Vibrio harveyi, by micro dilution method, was 1 μg/ml. This protein offers promise for use in hatcheries to control luminous vibriosis

Novel succinoylated carboxymethyl guar gum nanocarriers of glimepiride for controlling type-2 diabetes

In this study, guar gum (GG) was chemically modified to its carboxymethyl derivative, which was then esterified with octenyl succinic anhydride (OSA) using a nucleophilic catalyst 4-dimethylaminopyridine (DMAP) to render the derivative amphiphilic characteristics. The carboxymethyl guar gum (CMGG) and succinoylated CMGG was characterized using Fourier transform infrared spectroscopy (FTIR) spectroscopy. The amphiphilic CMGG synthesized using DMAP/OSA ratio of 0.5:1 (CMGGOSA-I), was found to be non-toxic. The amphiphilic guar gum self-assembled in water to form nanocarriers with mean diameter of 430 ​nm and zeta potential of −19.0 ​mV. Transmittance electron microscope (TEM) image showed spherical nature of the developed CMGGOSA-I nanocarriers. In presence of amphiphilic CMGG, the aqueous solubility of glimepiride was enhanced by about 67-fold. The nanocarriers released glimepiride in simulated gastrointestinal fluids for a period of more than 24 ​h, following Higuchi's kinetics. Korsmeyer-Peppas modeling of the drug release data revealed that a combination of swelling and diffusion mechanism was operative in the event of drug release. In streptozotocin-induced diabetic rat model, the nanocarriers outperformed pure drug suspensions in terms of anti-diabetic activity, which lasted up to 24 ​h. Overall; the newly synthesized amphiphilic CMGG nanocarriers demonstrated controlled drug release properties and showed promise for controlling type-2 diabetes

Prediction and validation of HIV-1 gp41 ecto-transmembrane domain post-fusion trimeric structure using molecular modeling

The glycoproteins on the surface of human immunodeficiency virus (HIV) undergoes cascade of conformational transitions to evade the human immune system. The virus replicates inside the host and infects the T-cells instigating acquired immunodeficiency syndrome (AIDS). The glycoprotein 41 (gp41) of HIV helps to mediate the fusion of virus and host membranes. The detailed mechanism of host cell invasion by virus remains obscure due to the unavailability of experimental structure of complete gp41. In the current study, the post-fusion (PoF) trimeric structure of ecto-domain including transmembrane domain of gp41 was modeled using multiple homologous templates of Simian immunodeficiency virus (SIV) and HIV-1. In order to validate the gp41 model, interactions of three peptide inhibitors: T20, C37 and C34; were studied using all-atom molecular dynamics (MD) simulations, binding free-energy calculation and per-residue energy decomposition analysis. The binding free energy calculated using MM-PBSA (Molecular Mechanics Poisson-Boltzmann surface area) method predicts maximum affinity for C34 and minimum by T20 for gp41, which is in good agreement with the available computational and experimental studies. The van der Waals interaction is a dominant contributor for the peptide-gp41 complexes. The per-residue decomposition of energy confirmed the role of Trp117, Trp120 and Ile124, present in C34 and C37, for the strong hydrophobic interactions with the deep pocket localized around the N-terminal of gp41, which is lacking in T20. The HIV-1 gp41 structure developed in this work can be used in future study to gain insight into the mechanism of virus invasion and probing potent inhibitor to eliminate AIDS

Application of Outer Membrane Protein-Based Vaccines Against Major Bacterial Fish Pathogens in India

Aquaculture is one of the fastest-growing food-producing sectors in the world. However, its growth is hampered by various disease problems due to infectious microorganisms, including Gram-negative bacteria in finfish aquaculture. Disease control in aquaculture by use of antibiotics is not recommended as it leads to antibiotic residues in the final product, selection, and spread of antibiotic resistance in the environment. Therefore, focus is on disease prevention by vaccination. All Gram-negative bacteria possess surface-associated outer membrane proteins (OMPs), some of which have long been recognized as potential vaccine candidates. OMPs are essential for maintaining the integrity and selective permeability of the bacterial membrane and play a key role in adaptive responses of bacteria such as solute and ion uptake, iron acquisition, antimicrobial resistance, serum resistance, and bile salt resistance and some adhesins have virulence attributes. Antigenic diversity among bacterial strains even within the same bacterial species has constrained vaccine developments, but OMPs that are conserved across serotypes could be used as potential candidates in vaccine development, and several studies have demonstrated their efficacy and potential as vaccine candidates. In this review, we will look into the application of OMPs for the design of vaccines based on recombinant proteins, subunit vaccines, chimeric proteins, and DNA vaccines as new-generation vaccine candidates for major bacterial pathogens of fish for sustainable aquaculture.publishedVersio