Potential of the HSP70 protein family as biomarker of Crassostrea virginica under natural conditions (Ostreoida: Ostreidae)

The HSP70 proteins are used as exposure biomarkers, and the oyster Crassostrea virginica is considered as a bioindicator organism in environmental assessment. According to the season, the level of expression of the HSP70 family in wild oysters has not been characterized before. The aim of this work was to analyze the expression of the HSP70 family as an exposure biomarker using C. virginica gills from individuals and groups of oysters from the Tampamachoco Lagoon under natural conditions. Ninety oyster samples were collected at locations from the Tampamachoco Lagoon during the dry and "north winds" seasons. One group of oysters was maintained under laboratory conditions and exposed to thermal stress. The pH, temperature, salinity, and dissolved oxygen (DO2) were measured inside the brackish Tuxpam-Tampamachoco system. Salinity and DO2 were outside the limits recommended for brackish systems in both seasons. The electrophoresis and immunodetection assay of HSP70 were performed using proteins from oyster gills. The HSP73, HSP72 and HSP69 isoforms were expressed in dry season tissue samples, while only the HSP73 and HSP72 isoforms were detected in north winds season tissue samples and positive control tissue samples. The HSP73 isoform has not been previously reported in C. virginica. To evaluate the expression of HSP70 protein family at individual and group levels from wild animals, it is also important to determine a seasonal baseline expression.

Las proteínas HSP70 se utilizan como biomarcadores de exposición y el ostión Crasostrea virginica es considerado como un organismo bioindicador en evaluaciones ambientales. De acuerdo con la estación, el nivel de expresión de la familia de las HSP70 en ostiones silvestres no ha sido caracterizado. El objetivo de este trabajo fue analizar la expresión de la familia de las proteínas HSP70 como un biomarcador de exposición utilizando branquias de C. virginica de manera individual y grupal bajo condiciones naturales. Noventa muestras de ostión se recolectaron en un sitio dentro de la Laguna Tampamachoco durante las estaciones de secas y "nortes". Un grupo se mantuvo bajo condiciones de laboratorio y expuesto a estrés térmico. El pH, la temperatura, la salinidad y el oxígeno disuelto (DO2) se midieron dentro del sistema salobre Tuxpan-Tampamachoco. La salinidad y el DO2 estuvieron fuera de los límites recomendados para sistemas salobres en ambas estaciones. La electroforesis y el ensayo de inmunodetección se llevaron a cabo con branquias de ostiones. Las isoformas HSP73, HSP72 y HSP69 se expresaron en tejido de las muestras de la época de secas, mientras que solamente las isoformas HSP73 y HSP72 se detectaron en tejido de las muestras de época de nortes y control positivo. La isoforma HSP73 no ha sido reportada previamente en C. virginica. Para evaluar la expresión de la familia de las proteínas HSP70 a nivel individual y grupal de organismos silvestres es importante determinar una línea de base de expresión estacional.

Caulerpa lentillifera and Sucrose Formulated Diets as Growth Enhancer of Oyster (Crassostrea virginica)

A total of 200 of Crassostrea virginica populations of average weight range from 41.19 ± 3.42 to 47.53 ± 1.06 g were studied to determine the effect of the feed diets of Caulerpa lentillifera and sucrose as growth enhancement. Growth rates increased that range from 56.99 ± 3.16 to 61.56 ± 2.87 g for 90 days period using an artificial water tank system. Previous studies conducted that C. lentillifera contained high protein and were the most abundant component. This seaweed also contained high amounts of minerals and balanced amino acid and notably very rich in iodine. phosphorus, calcium, magnesium and copper that will contribute to oysters growth. Oysters are known to have the ability to uptake dissolved organic matter as nutrients. In the present study, the effects of culture water supplemented with sucrose were tested on oysters. Results revealed that this organic matter promotes growth to the oysters. Sugars will be metabolized into pyruvate through the glycolysis pathway and will result in the supply of energy. Therefore, supplementation of sugar to oysters may have contributed as an energy source together with the lipid and protein content from the algae diet.

Variación del ciclo gonádico del ostión americano, Crassostrea virginica (Ostreoida: Ostreidae) en función de su talla en la laguna de Tamiahua, Veracruz, México / Variation of gonadal cycle of the american oyster, Crassostrea virginica (Ostreoida: Ostreidae) as a function of height in Tamiahua Lagoon, Veracruz, Mexico

The American oyster, Crassostrea virginica is one of the most important fishery resources of the Gulf of Mexico, where it has been classified as “resource exploited at maximum”. Since 1994 state authorities set a minimum extraction shell length of 70 mm (adult size); this was based on population studies alone. We compare the gonadal cycle of subadults oysters with adult organisms. From January to December 2011, 90 oysters were collected monthly in Tamiahua Lagoon, Veracruz and classified as subadults (50-69mm; 75% of sample) and adults (≥70mm). Histological gonad sections were classified in four categories: rest, gametogenesis, maturation and release of gametes. In subadults, the rest stage had two peaks (January 22% and June 13%), and gametogenesis between January and July (22-74%). Maturation was observed in July, August and September (40, 64 and 41% respectively) and release in October (66%) and November (45%). Correspondingly, adults were resting in January and June (17 and 13%), and January-July gametogenesis (56-88%), matured in August and September (64 and 42%) and released gametes in September and October (54 and 70%). The gametogenic cycle was similar in subadults and adults: the species breeds from sizes equal or smaller than 50 mm and this should be considered by authorities. Rev. Biol. Trop. 62 (Suppl. 3): 201-206. Epub 2014 September 01.

El ostión americano (Crassostrea virginica) es uno de los recursos de pesca mas importantes en el Golfo de México, donde es clasificado como “recurso aprovechado al máximo”. Desde 1994 las autoridades estatales fijaron una talla mínima de extracción de 70mm de longitud de concha (tamaño adulto); esto basado en estudios aislados de poblaciones. Comparamos el ciclo gonadal de subadultos y adultos. De enero a diciembre de 2011, se colectaron 90 ostiones mensualmente en la laguna de Tamiahua, Veracruz y se clasificaron como subadultos (40-69 mm) y adultos (>70mm). Los cortes histológicos de las gónadas se clasificaron en cuatrocategorías: reposo, gametogénesis, maduración y liberación de gametos. En subadultos, la categoría de reposo tuvo dos picos (enero 22% y junio 13%) y la gametogénesis entre enero y julio (22-74%). La maduración se observó en julio, agosto y setiembre (40, 64 y 41%) y la liberación en octubre (66%) y noviembre (74%). Correspondientemente, los adultos reposaban en enero y junio (17 y 13%), y la gametogénesis entre enero y julio (56-88%), maduraban en agosto y setiembre (64 y 42%) y liberaban gametos en setiembre y octubre (54 y 70%). El ciclo gametogénico fue similar entre ostiones subadultos y adultos: la especie se reproduce con tamaños igual o inferior a 50mm y esto lo deben considerar las autoridades.