ABSTRACT
Abstract One way of reducing the input of pollutants into the marine environment is to enforce the use of non-toxic antifouling paints in marine protected areas. Thus, the purpose of this study was to detect marine microorganisms that secrete inhibitory substances against bacteria and microalgae to avoid biofouling on manmade structures in La Paz bay, B.C.S., Mexico. The inhibitory potential of 125 bacteria was evaluated against biofilm-forming bacteria. Crude extracts were obtained with methanol and ethyl acetate from 16 bacterial strains that exhibited antagonistic and antibacterial activity in a preliminary screening. Antibacterial and antimicroalgal assays were performed using crude extracts, the minimum inhibitory concentration (MIC) was determined. The highest activity against bacteria and microalgae was found in two strains, Shewanella algae and Staphylococcus sp. The results of this study suggest that extracts of bacteria from the Gulf of California with antimicrobial properties against biofilm-forming bacteria can also prevent the adhesion of microalgae, which may control the development of biofilm formation and, as a consequence, biofouling.(AU)
Resumen Una alternativa para reducir la contaminación en el medio marino es el uso de pinturas anti-incrustantes no tóxicas en áreas marinas protegidas. En el presente estudio se propuso encontrar microorganismos marinos que secreten sustancias capaces de inhibir la adhesión de bacterias y microalgas, de esta manera evitar la bioincrustación en estructuras marinas en la bahía de La Paz, B.C.S., México. Un total de 125 bacterias fueron evaluadas por su capacidad para inhibir el desarrollo de bacterias formadoras de biopelículas. En una selección preliminar de actividad antagónica y antibacteriana, 16 cepas bacterianas mostraron potencial actividad inhibitoria, de las que se obtuvieron los extractos crudos con metanol y acetato de etilo. Se realizaron ensayos antibacterianos y anti-microalgales utilizando los extractos crudos, se determinó la concentración mínima inhibitoria (MIC). Dos cepas mostraron la mayor actividad contra bacterias y microalgas: Shewanella algae y Staphylococcus sp. Los resultados de este estudio sugieren que los extractos de bacterias aisladas en el Golfo de California que poseen propiedades antimicrobianas contra las bacterias formadoras de biofilm y también pueden prevenir la adhesión de microalgas, con lo que se podría controlar el desarrollo de la formación de biopelículas y como consecuencia, el biofouling.(AU)
Subject(s)
Sea Water Pollution/prevention & control , Shewanella , Biofouling , Microalgae , California , MexicoABSTRACT
Abstract Parasitic diseases have caused significant problems to global aquaculture production. These studies will further our knowledge of this complex problem and help implement adequate prevention measures and control strategies. The present study aimed to investigate the presence of parasites in Megaleporinus obtusidens and to describe the epidemiology and pathology of parasitic infections in these fish. Five moribund fish were sent for parasitological examination. The integument and gills were scrapped off with a glass slide, and samples were examined under a light microscope. Parasitic crustaceans found in these specimens were submitted for scanning electron microscopy and histological analyses. The crustaceans Dolops carvalhoi and Lernaea cyprinacea and the Epistylis spp. were present in all fish examined. Epistylis spp. were also seen on the entire surface of the crustacean integument. Microscopic lesions observed in the parasitized gills included hyperplasia and hypertrophy of the lamellar epithelium, an inflammatory infiltrate, telangiectasia, foci of hemorrhage and necrosis, fusion of the secondary lamellae, and detachment of the lamellar epithelium. Crustacean parasites are important mechanical vectors of Epistylis infection and disseminate the disease in fish farming operations. Epistylis spp. infection affects the health of fish and has significant ecological and economical impact on aquaculture.
Resumo Doenças parasitárias causam problemas significativos a produção mundial de peixes. Esse estudo aprofundará nosso conhecimento neste complexo problema e ajudará implementar estratégias de prevenção e controle. O objetivo deste trabalho foi analisar os parasitas encontrados em Megaleporinus obtusidens de piscicultura extensiva e descrever as relações epidemiológicas e patológicas entre eles. Cinco peixes moribundos foram enviados para análise parasitológica. O tegumento e as brânquias foram raspados com lâminas de vidro e examinados em microscópio óptico. Os crustáceos parasitas foram processados para análises histologicas e de microscopia eletrônica de varredura. Todos os peixes analisados foram infestados pelos crustáceos Dolops carvalhoi, Lernaea cyprinacea e pelo Epistylis spp. Epistylis spp. foram também encontrados na superfície de todo tegumento dos crustáceos parasitas. As brânquias parasitadas apresentaram hiperplasia e hipertrofia do epitélio lamelar, infiltrado inflamatório, telangectasia, focos hemorrágicos e necróticos, extensas áreas com fusão de lamelas secundárias e desprendimento de epitélio lamelar. Os crustáceos parasitas são vetores mecânicos importantes da epistilíase, disseminando o microorganismo nas criações de peixes. A infestação por Epistylis spp. afeta a saúde dos peixes e tem impacto ecológico e econômico significativo na aquacultura.
Subject(s)
Animals , Ciliophora/ultrastructure , Characiformes/parasitology , Microscopy, Electron, Scanning , Ciliophora/isolation & purification , Ciliophora/classification , Aquaculture , Characiformes/classification , Host-Parasite InteractionsABSTRACT
En el cultivo de camarones L. vannamei se producen afecciones sanitarias y productivas por la presencia de protozoos ciliados epibiontes. En Cuba no existen referencias de cómo varía su manifestación a medida que avanza el cultivo, por lo que se realizó un estudio con el objetivo de determinar la prevalencia general y específica y el grado de severidad de las afecciones por protozoos epibiontes durante el ciclo de engorde del camarón. Para ello, se examinó durante tres ciclos un total de 2880 ejemplares (juveniles y adultos) en la camaronera Tunas de Zaza, provincia de Sancti Spiritus, Cuba. Se expuso la tendencia de los parámetros evaluados, a partir de muestreos semanales y el análisis en fresco y por las características evidentes para cada especie. Los resultados se analizaron mediante modelos de tendencia, partiendo del método de mínimos cuadrados. Las posibles diferencias entre las prevalencias específicas se analizaron mediante las pruebas no paramétricas de Kruskall Wallis y la U de Mann Whitney, utilizando el programa estadístico SPSS, V15. Los resultados muestran que los géneros de protozoos epibiontes observados que mostraron un mayor grado de severidad (GS) en sus lesiones fueron: Epistylis sp., con mayor prevalencia (GS: 1 a 4), seguido por Acineta sp. (GS: 1 a 4); Zoothamnium sp. (GS: 1 a 2) y Ascophrys (GS: 1), con un comportamiento en ascenso a medida que avanzaba el cultivo.
In shrimp (L. vannamei) farming, alterations in health and in productive performance occur. These disorders result from the presence of ciliated epibionts protozoan. In Cuba, there is no data available on how their expression varies as the culture progresses. The purpose of this study was to determine the general prevalence, the specific prevalence, and the degree of severity of the effects caused by epibionts protozoan during the fattening cycle of shrimp. To conduct the study, 2880 shrimp samples (juvenile and adults) were evaluated at the Tunas de Zaza shrimp farm for three cycles. The trend of the evaluated parameters was studied, based on weekly analysis of fresh samples and the obvious characteristics of each species. The results were analyzed using trend models, based on the least squares method. The possible differences among specific prevalence were tested by the Kruskall Wallis and Mann Whitney U nonparametric tests, using the statistical program SPSS V15. The results show that the genera of epibionts protozoa observed which exhibited greater degrees of severity (DS) in their lesions were Epistylis sp., with higher frequency (DS: 1 to 4), followed by Acineta sp. (DS: 1 to 4), Zoothamnium sp. (DS: 1 to 2), and Ascophrys (GS: 1), with a rising behavior as the culture progressed.