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

Probiotic potential of exopolysaccharide producing lactic acid bacteria isolated from homemade fermented food products

In the current study, 41 bacterial isolates were obtained from homemade fermented food products (cheese, curd, fermented rice water, yogurt, and buttermilk). Among these bacterial isolates, 4 lactic acid bacteria (LAB) strains such as CH4, Sri3, Kri1, and R3 were screened based on their wide inhibitory potential against test indictors by the well diffusion method. Based on the morphological, biochemical and phylogenic characterization, the four selected probiotic LAB strains were identified viz., Lactococcus hircilactis strain CH4, Lactobacillus delbrueckii strain GRIPUMSK, Lactobacillus johnsonii strain PUMSKGRI, and Lactobacillus leichmannii strain SKGRIPUM. These 4 probiotic LAB strains exhibited 62.5–87.5% antibiotic sensitivity, non-haemolytic, thereby confirming their safe status. All of these strains were found to be extremely acid tolerant after 5 h at pH 2–3. These 4 strains were able to withstand 2% high bile salt concentrations for 5 h with a survival rate of 67.40–73.68%. After 5 h, all four isolates demonstrated good auto-aggregation capacity of greater than 40% and strong hydrophobicity towards xylene of greater than 40%. All the four selected isolates have produced antimicrobial metabolites of exopolysaccharides (196.4 U/mL- 217.9 U/mL), H2O2 (0.49–0.71 g L−1) and β-galactosidase (196.4–217.9 U/mL). These strains exhibited the ability to assimilate cholesterol ranged between 12.15 and 79.72%. Moreover, they were found to be highly potential, with a total score of 95.83%, and are now being used to make probiotic food products. Hence, this work affirms the use of selected four LAB strains as safe and highly effective probiotic candidates

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

Oreochromis mossambicus diet supplementation with Psidium guajava leaf extracts enhance growth, immune, antioxidant response and resistance to Aeromonas hydrophila

In this research, we focused on the efficacy of aqueous and ethanol leaf extracts of Psidium guajava L. (guava) based experimental diets on the growth, immune, antioxidant and disease resistance of tilapia, Oreochromis mossambicus following challenge with Aeromonas hydrophila. The experimental diets were prepared by mixing powdered (1, 5 and 10 mg/g) aqueous and ethanol extract of guava leaf with commercial diet. The growth (FW, FCR and SGR), non-specific cellular immune (myeloperoxidase activity, reactive oxygen activity and reactive nitrogen activity) humoral immune (complement activity, antiprotease, alkaline phosphatase activity and lysozyme activity) and antioxidant enzyme responses (SOD, GPX, and CAT) were examined after 30 days of post-feeding. A significant enhancement in the biochemical and immunological parameters of fish were observed fed with experimental diets compared to control. The dietary supplementation of P. guajava leaf extract powder for 30 days significantly reduced the mortality and increased the disease resistance of O. mossambicus following challenge with A. hydrophila at 50 μl (1 × 107 cells ml−1) compared to control after post-infection. The results suggest that the guava leaf extract could be used as a promising feed additive in aquaculture

Green larvicides against blowflies, Lucilia sericata (Diptera, Calliphoridae): Screening of seven plants used in Indian ethno-veterinary medicine and production of green-coated zinc oxide nanoparticles

Dipteran flies are responsible of myiasis, a common parasitic infestation leading to the invasion of living, necrotic or dead tissues. They also transmit mycobacterial infections to livestock. In the present investigation, seven plant species employed in Southern India for medical and ethno-veterinary purposes were extracted using ethanol or water and tested against second instar larvae of Lucilia sericata 100% larval mortality was observed testing Lobelia leschenaultiana ethanol extract at 60 mg/L (LC50 = 3.4 mg/L). Based on the highest percentage of larval mortality, we selected L. leschenaultiana for fabrication of ZnO nanoparticles to control L. sericata. Zinc acetate showed 82.2% mortality at 60 mg/L (LC50 = 38.2 mg/L) whereas L. leschenaultiana-coated ZnO nanoparticles (Ll-ZnO NPs) showed 100% mortality at 6 mg/L, the LC50 was 0.78 mg/L. Overall, our research represents an attempt to integrate current ethno-veterinary knowledge from native tribes of Southern India, in order to identify effective botanicals for the development of nano-biopesticides against livestock pests and parasites