Assessment of the effect of green synthesized silver nanoparticles against aquatic pathogen Aeromonas hydrophila using Artemia nauplii

1831-1838Fish disease is a major threat affecting the long-term development of aquaculture industry leading to great economic loss annually. Aeromonas hydrophila bacterium may be a primary or secondary cause of ulcers, hemorrhagic septicemia, fin rot and tail rot in fishes. Excess and abandoned usage of antibiotic substances caused a substantial growth of antibiotic resistant pathogens. Now a days, enduring research has focused on improvement of nanomaterials for efficient antimicrobial therapies. Comparing to the synthesis of other metallic nanoparticles, silver nanoparticles (AgNPs) has gained much attention because of its unique antimicrobial properties. The present study was aimed to green synthesize AgNPs using the Annona squamosa leaf extract which acts as a non-toxic reducing agent. The synthesized AgNPs were evaluated for biocompatibility and antagonistic efficacy against A. hydrophila. The green synthesized AgNPs were bio-physically characterized by UV-Visible spectroscopy, X-ray powder diffraction, High Resolution Transmission Electron Microscope, Fourier-transform infrared spectroscopy and Zeta Potential analysis. The particles were almost spherical shaped and in the range of 15-25 nm. Green synthesized AgNPs exhibited significant DPPH radical scavenging activity (64.62 %). Synthesis of AgNPs using widely available plants can be promoted as a potential eco-friendly option to chemical methods used for nanosynthesis. In-vivo studies confirmed that the AgNPs exhibited good antagonistic against A. hydrophila and also proved its non-toxic effect to Artemia salina nauplii

<span style="font-size: 20.5pt;mso-bidi-font-size:14.5pt;font-family:"Times New Roman","serif"">Toxicity assessment of wild bean seed protein - Arcelin on Asian armyworm, <i><span style="font-size:20.0pt;mso-bidi-font-size:14.0pt;font-family:"Times New Roman","serif"">Spodoptera litura </span></i><span style="font-size:20.5pt;mso-bidi-font-size:14.5pt;font-family:"Times New Roman","serif"">(Fabricius) </span></span>

1463-1465<span style="font-size: 14.5pt;mso-bidi-font-size:8.5pt;font-family:" times="" new="" roman","serif""="">Arcelin, an anti-metabolic protein was purified from the seeds of wild bean, Lablab purpureus. The feeding assay containing arcelin at 5, 10 and 15 μg concentrations revealed no antifeedant effect against fifth instar larvae of S. <span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;font-family: " times="" new="" roman","serif""="">litura. <span style="font-size:14.5pt; mso-bidi-font-size:8.5pt;font-family:" times="" new="" roman","serif""="">However, the enhanced activity of <span style="font-size:10.5pt;mso-bidi-font-size: 4.5pt;font-family:" arial","sans-serif""="">(α- <span style="font-size:14.5pt; mso-bidi-font-size:8.5pt;font-family:" times="" new="" roman","serif""="">and β-naphthyl esterases in the mid-gut samples of <span style="font-size:15.5pt;mso-bidi-font-size: 9.5pt;font-family:" times="" new="" roman","serif""="">S. litura <span style="font-size:14.5pt;mso-bidi-font-size:8.5pt;font-family: " times="" new="" roman","serif""="">treated with arcelin suggests countermeasure against the toxic effect of arcelin. </span

GFP tagged Vibrio parahaemolyticus Dahv2 infection and the protective effects of the probiotic Bacillus licheniformis Dahb1 on the growth, immune and antioxidant responses in Pangasius hypophthalmus

In this study, the pathogenicity of GFP tagged Vibrio parahaemolyticus Dahv2 and the protective effect of the probiotic strain, Bacillus licheniformis Dahb1was studied on the Asian catfish, Pangasius hypophthalmus. The experiment was carried out for 24 days with three groups and one group served as the control (without treatment). In the first group, P. hypophthalmus was orally infected with 1 mL of GFP tagged V. parahaemolyticus Dahv2 at two different doses (105 and 107 cfu mL1). In the second group, P. hypophthalmus was orally administrated with 1 ml of the probiotic B. licheniformis Dahb1 at two different doses (105 and 107 cfu mL1). In the third group, P. hypophthalmus was orally infected first with 1 mL of GFP tagged V. parahaemolyticus Dahv2 followed by the administration of 1 mL of B. licheniformis Dahb1 (combined treatment) at two different doses (105 and 107 cfu mL1). The growth, immune (myeloperoxidase, respiratory burst, natural complement haemolytic and lysozyme activity) and antioxidant (glutathione-S-transferase, reduced glutathione and total glutathione) responses of P. hypophthalmus were reduced after post infection of GFP tagged V. parahaemolyticus Dahv2 compared to control. However, after administration with the probiotic B. licheniformis Dahb1 at 105 cfu mL1, P. hypophthalmus showed significant increase in the growth, immune and antioxidant responses compared to 107 cfu mL1. On the otherhand, the growth, immune and antioxidant responses of P. hypophthalmus infected and administrated with combined GFP tagged Vibrio þ Bacillus at 105 cfu mL1 were relatively higher than that of GFP tagged V. parahaemolyticus Dahv2 and control groups but lower than that of probiotic B. licheniformis Dahb1 groups. The results of the present study conclude that the probiotic B. licheniformis Dahb1 at 105 cfu mL1 has the potential to protect the P. hypophthalmus against V. parahaemolyticus Dahv2 infection by enhancing the growth, immune and antioxidant responses. The probiotic B. licheniformis Dahb1 would be effectively used in the treatment of aquatic diseases for improvement of aquaculture industry