Secondary metabolites of the green algae, Ulva fasciata, were tested to determine the efficacy of controlling shrimp bacterial pathogens. Exploratory experiments indicated that an intermediate dose (1 g kg-1 of shrimp) of Ulva in the diet was highly effective at controlling bacterial pathogens of shrimp, as compared to lower (500 mg kg-1) and higher (1.5 g kg-1) doses. The pilot experiments evaluated the percent of relative protection afforded shrimps treated with Ulva diet and faced with various concentrations of bacterial pathogen. The survival of shrimps treated with Ulva diet was significant (P < 0.01). The present findings indicate that the green U. fasciata may be an excellent source for developing a potent medicated feed for shrimp disease management.

Metabolites secundario de algas verdes Ulva fasciata fue probado para determinar la eficacia de controlar el camarón pathogens bacterial. Las conclusiones de experimentos exploratorios indicaron que la dosis mediana (1 g kg-1 de camarón) de dieta Ulva era sumamente eficaz en el control de pathogens bacterial de camarón cuando comparado al más abajo (500 mg kg-1) y más alto (1,5 g kg-1) dosis. En los experimentos pilotos, la protección de pariente de por ciento de camarones trató con la dieta Ulva y desafió con varias concentraciones de bacterial patógeno fueron evaluados. La supervivencia de camarones trató con la dieta Ulva era significativo (P < 0,01). Basado en las conclusiones presentes, podría ser deducido que U. verde fasciata puede ser una fuente excelente para desarrollar la comida potente medicinal para la dirección de enfermedad de camarón.

The response of two marine actinomycetes such as Streptomyces sp. MADO2 and Nocardiopsis sp. MADO3 to osmotic stress in minimal medium M63 and in glycerol-asparagine medium (ISP5) was studied. The two strains were moderately halophilic and the behavior of the strain Streptomyces sp. MADO2 and Nocardiopsis sp. MADO3 towards the salt stress was varied depends on the media composition and the salinity concentration. The strain Streptomyces sp. was more sensitive to salt stress than Nocardiopsis sp. The growth of both Streptomyces sp. and Nocardiopsis sp. were inhibited at 1 M NaCl irrespective of the medium used. The Nocardiopsis sp. acquired osmoadaptation on ISP5 medium whereas the Streptomyces sp. showed poor growth on M63 medium. Glycine betaine (GB), proline and trehalose played a critical role in osmotic adaptation at high osmolarity whereas at low osmolarity they showed an inhibitory effect on the bacterial growth. The present findings confirmed that GB was the powerful osmoprotectant for Streptomyces sp. and Nocardiopsis sp. grown at 1 M NaCl both in M63 and ISP5 media.

Entre as diversas variedades de algas vermelhas, Asparogopsis taxiformis constitui uma das que apresentam alta biomassa na costa de Kollam (Sudoeste da Índia). No presente estudo A. taxiformis foi coletada, seca e reduzida a pó, após o que foi realizada sua extração e feito o fracionamento usando-se cromatografia por coluna. As frações individuais foram avaliadas in vitro em ensaios para testar sua capacidade anti-incrustante, anticianobacteria e toxicidade para peixes e crustáceos. A fração extraída com eter de petróleo e etil acetato (2:8) apresentou o espectro de bioatividade mais forte e amplo. No ensaio anti-incrustação efetuado com com o molusco pulmonado Limnea truncatula, a fração algal ativa produziu 80% de repelência do pé em 150 mg/l, enquanto que no ensaio anticianobacteria a fração ativa inibiu 100% do crescimento de Trichodesmium sp., em 320 mg/l. A fração algal mostrou o efeito mais intenso contra peixes no nível de 60 mg/l. Em relação aos crustáceos, a toxicidade da fração ativa foi avaliada também visando encontrar compostos não tóxicos para organismos não alvo, tais como Penaeus monodon e Macrobrachium rosembergii. Foi visto que a fração ativa da coluna mostrou menor toxicidade para estas espécies. Os componentes químicos da fração ativa foram identificados por meio dos sistemas cromatográficos, tais como TLC, fase reversa do HPLC e GC-MS. O perfil geral de atividade aponta que a fração ativa da coluna para A. taxiformis pode conter metabolitos bioativos sinérgicos que podem ser utilizados para o controle de organismos incrustantes, explosão algal e peixes herbiboros/predadores em tanques de aquicultura.

Among the diverse variety of red algae, Asparagopsis taxiformis constitutes one of the abundant biomass in the Kollam coast (Southwest coast of India). Therefore, in the present study, A. taxiformis was collected, extracted and fractionated using column chromatography. The individual fractions were evaluated in vitro for their antifouling, anticyanobacterial, piscicidal and crustaceans toxicity assays. The fraction eluted with 2:8, petroleum ether and ethyl acetate exhibited strong and broad spectrum of bioactivity. In antifouling assay against Limnea truncatula, the active algal fraction produced 80% of foot repellency at 150 mg/L whereas in anticyanobacterial assay, the active fraction inhibited 100% growth of Trichodesmium sp. at 320 mg/L. The algal fraction showed higher piscicidal effect at the level of 60 mg/L. The crustacean toxicity of the active fraction was also evaluated to find compounds without toxicity in non target organisms, Penaeus monodon and Macrobrachium rosenbergii. It was found that column fraction showed less toxicity against the non target organisms. The chemical constituents of the active fraction were identified by means of chromatographic systems such as TLC, reverse phase HPLC and GC-MS. The overall activity profile envisages that the active column fraction of A. taxiformis might contain synergistic bioactive metabolites that could be utilized for the control of fouling organisms, algal bloom and herbivorous/predaceous fishes in aquaculture ponds.

The main goal of this study was to evaluate the prevalence of leptospirosis among field rodents of Tiruchirappalli district, Tamil Nadu, India. In total 35 field rats were trapped and tested for seroprevalence by the microscopic agglutination test (MAT). Isolation of leptospires was performed from blood and kidney tissues and characterized to serovar level. Genomospecies identification was carried out using 16S rRNA and lipL32 gene sequencing. The molecular phylogeny was constructed to find out species segregation. Seroprevalence was about 51.4 %, and the predominant serovars were Autumnalis, Javanica, Icterohaemorrhagiae and Pomona. Two isolates from the kidneys were identified as serovar Javanica of Serogroup Javanica, and sequence based molecular phylogeny indicated these two isolates were Leptospira borgpetersenii.