Interaction of Biomphalaria cells in primary cultures with Schistosoma mansoni sporocysts

Abstract INTRODUCTION: Biomphalaria snails may display varying levels of susceptibility to Schistosoma mansoni infection. We have been developing an in vitro model to study the interaction between the snail and the parasite, using tissue-derived cell cultures from Biomphalaria. METHODS: The digestive gland- and kidney-derived cells from primary cultures of resistant (B. tenagophila Taim) and susceptible (B. tenagophila HM and B. glabrata BH) strains of Biomphalaria were exposed to S. mansoni sporocysts. RESULTS: S. mansoni sporocysts were surrounded and encapsulated exclusively by cells derived from the digestive gland (DG) of B. tenagophila Taim. The process was followed by a marked decrease in the number of free sporocysts in the culture medium. The morphological characteristics of DG-derived cells in culture have been described. CONCLUSIONS: Cells derived from DG (but not SK) primary cultures of B. tenagophila Taim may participate in S. mansoni sporocyst control.

Histomorphologic characterization of the hepatopancreas of freshwater prawn Macrobrachium rosenbergii (De Man, 1879) / Caracterização histomorfológica do hepatopâncreas do camarão-de-água-doce Macrobrachium rosenbergii (De Man, 1879)

This study aimed to describe the Macrobrachium rosenbergii hepatopancreas histomorphology. The hepatopancreas is constituted by a set of blind end tubules, divided into proximal, middle, and distal regions, with the epithelium formed by E, F, B, R, and M cells differently of other species. Measurements of the length and width of the tubules were 419.64+69.09µm and 117.42+16.99µm, respectively. The percentage of each cell type per region was: proximal region (40%B, 20%F, 6.7%M, 33.3%R), middle region (45.4%B, 18.2%F, 9.1%M, and 27.3%R) and distal region (36.4%E, 27.2%B, 18.2%F, 9.1%M, 9.1%R). Cell B that stores glycogen and lipids, is the most commonly found cell in proximal and middle regions. In the distal region, the E, responsible for the mitosis, is the most prominent. M, responsible by nutrient storage, is numerically constant among the portions differently in the Macrobrachium amazonicum. The study for the first time also suggests that in addition to digestive enzymes, the F cell produces protective mucus. The present study generated for the first time a morphometric profile of M. rosenbergii hepatopancreas, demonstrating differences from other species, and can be an important tool for new studies in nutrition, reproduction, and production with the species.(AU)

O objetivo do presente estudo foi descrever a histomorfologia do hepatopâncreas do camarão-de-água-doce Macrobrachium rosenbergii. Observou-se que ele é constituído por um conjunto de túbulos de fundo cego, sendo cada túbulo dividido em regiões proximal, média e distal, com o epitélio formado por cinco tipos de células (E, F, B, R, M), diferentemente de outras espécies. As medidas de comprimento e largura dos túbulos foram de 419,64+69,09µm e 117,42+16,99µm, respectivamente. A porcentagem de cada tipo celular por região foi: região proximal (40%B, 20%F, 6,7%M, 33,3%R), região média (45,4%B, 18,2%F, 9,1%M e 27,3%R) e região distal (36,4%E, 27,2%B, 18,2%F, 9,1%M, 9,1%R). Assim, a B, que armazena glicogênio e lipídeos, é a célula mais encontrada nas regiões proximal e média. Na região distal, a célula E, responsável pela mitose, é a mais encontrada. A célula M, responsável pelo acúmulo de nutrientes, tem um número constante de células nas porções do túbulo, diferentemente do Macrobrachium amazonicum. O estudo também sugere, pela primeira vez, que a célula F produz, além de enzimas digestivas, um muco protetor para o túbulo hepatopancreático. O presente estudo foi o primeiro a gerar um perfil morfométrico do hepatopâncreas do M. rosenbergii e demonstrou diferenças em relação a outras espécies, bem como serviu de importante ferramenta para novos estudos que abranjam a produção, a nutrição e a reprodução para a espécie.(AU)

In vitro digestibility of specific dsRNA by enzymes of digestive tract of shrimp Litopenaeus vannamei / Digestibilidad in vitro del dsRNA específico por enzimas del tracto digestivo del camarón Litopenaeus vannamei

ABSTRACT Objective. The digestibility of specific dsRNA by action of the enzymes of digestive tract of the whiteleg shrimp Litopenaeus vannamei was determined in vitro. Materials and methods. Digestive enzyme activity (amylase, lipase, protease, DNase and RNase) was measured in the stomach, digestive gland, and anterior, middle, and posterior intestine of juvenile shrimp, and the digestibility of DNA, RNA and the dsRNA-ORF89, specific to WSSV, was determined by in vitro assays, as well as electrophoretic and densitometric analyses. Results. The highest enzymatic activity was found in the digestive gland: amylase (81.41%), lipase (92.60%), protease (78.20%), DNase (90.85%), and RNase (93.14%). The highest digestive capacity against DNA, RNA, and dsRNA was found in the digestive gland (5.11 ng of DNA ​​per minute, 8.55 ng of RNA per minute, and 1.48 ng dsRNA per minute). Conclusions. The highest digestibility of dsRNA-ORF89, specific to WSSV, was found in the digestive gland, whereas the lowest digestibility was observed in the posterior intestine. This is the first report regarding the digestibility of dsRNA-ORF89 by whiteleg shrimp digestive tract enzymes, with potential therapeutic importance in shrimp culture to prevent WSSV disease through balanced feed.

RESUMEN Objetivo. La digestibilidad del dsRNA específico para el virus de la mancha blanca (WSSV) por acción de las enzimas del tracto digestivo del camarón Litopenaeus vannamei fue analizada in vitro. Materiales y métodos. Se midió la actividad de enzimas digestivas (proteasa, amilasa, lipasa, ADNasa y ARNasa) en el estómago, la glándula digestiva, el intestino anterior, medio y posterior en juveniles de camarón patiblanco y se evaluó la digestibilidad de ácidos nucleicos ADN, ARN y dsRNA-ORF89 especifico contra el virus WSSV, por análisis electroforéticos y densitometría. Resultados. La actividad enzimática más alta se encontró en la glándula digestiva del camarón: amilasa (81.41%), lipasa (92.60%), proteasa (78.20%), ADNasa (90.85%) y ARNasa (93.14%). Se evidenció la capacidad digestiva del camarón patiblanco contra el ADN, ARN y dsRNA-ORF89 encontrando en la glándula digestiva la mayor digestión (5.11 ng de ADN por minuto, 8.55 ng de ARN por minuto y 1.48 ng de dsRNA por minuto). Conclusiones. La mayor digestibilidad del dsRNA-ORF89, específico contra el virus WSSV, se encontró en la glándula digestiva y la menor en el intestino posterior. Este es el primer informe relacionado con la digestibilidad del dsRNA-ORF89 por las enzimas del camarón patiblanco con potencial importancia terapéutica en el cultivo de camarón para prevenir la enfermedad del WSSV a través del alimento balanceado.

Histoquímica de la glándula digestiva en la ostra perla Pinctada imbricata (Pterioida: Pteriidae) durante su ciclo gametogénico, Venezuela / Histochemistry of the digestive gland of the pearl oyster Pinctada imbricata (Pterioida: Pteriidae) during the gametogenic cycle, Venezuela

ResumenLas técnicas histoquímicas hoy en día permiten seleccionar áreas de tejido y generar información confiable sobre la distribución de reservas energéticas en los moluscos bivalvos durante su ciclo de vida. Mensualmente se examinaron las gónadas y la glándula digestiva (GD) de 15 individuos recolectados entre abril 2012 y febrero 2013 por técnicas histológicas e histoquímicas de microscopia de luz, para relacionar el ciclo gametogénico y la disponibilidad de reservas energéticas con los parámetros ambientales. En el ciclo gametogénico, la proporción mensual de organismos maduros fue mayor en los machos entre agosto (40 %) y noviembre (53 %), mientras que las hembras tienden a presentar un ciclo más corto y sincronizado de liberación de gametos (septiembre 67 % y octubre 60 %). Los períodos intensos de desoves coinciden en ambos sexos (octubre-enero). Entre abril-agosto 2012 y enero-febrero 2013, se observan los valores más altos del IGl (índice de glúcido), mientras que en septiembre disminuyen y alcanzaron valores mínimos entre octubre y diciembre. El IL (índice de lípidos) presentó valores máximos en abril-2012 y febrero-2013, con un valor intermedio en agosto. Los resultados indican que las reservas de la GD presentan un patrón de movilización en relación inversa con la proliferación de los gametos de ambos sexos, vinculado directamente con la disponibilidad de nutrientes como la clorofila a y el seston orgánico.

AbstractHistochemical techniques today allow you to select areas of tissue and generate reliable information on the distribution of energy reserves in bivalve molluscs during their life cycle. The main objective of this study was to describe and relate the gametogenic cycle with the availability of energy reserves and the environmental parameters. For this, we sampled and examined the gonads and digestive glands (DG) of 15 individuals collected monthly during April 2012 and February 2013. We processed and analyzed the samples by standard histological and histochemical light microscopy techniques. Our results showed that for the gametogenic cycle, the monthly proportion of mature organisms was higher for males, between August (40 %) and November (53 %), while the females tend to have a shorter synchronized cycle and release of gametes in September (67 %) and October (60 %). The intense spawning periods in both sexes was the same (October to January). Between the periods April-August 2012 and January-February 2013, we observed the highest values of IGl and glucide index (instead, a decrease was observed in September, reaching minimum values during the period October-December). Besides, the maximum values of IL, lipid index, were observed in April-2012 and February-2013, with an intermediate value in August-2013. The results indicated that the reserves of the GD have a pattern of mobilization inversely related to the proliferation of gametes in both sexes; this was directly linked to the availability of nutrients such as chlorophyll a and the organic seston. Rev. Biol. Trop. 64 (2): 849-858. Epub 2016 June 01.