Comparative study of gonadal development of Ruditapes philippinarum (Adams and Revé) and Ruditapes decussatus (L.) (Mollusca, Bivalvia): Influence of temperature

Laboratory experiments were used to study the influence of temperature on the reproductive behaviour of two species of clam, Ruditapes decussatus and Ruditapes philippinarum, during their adaptation to the temperature conditions of Galician coastal waters. In both species the rate of gonadal development was directly related to the increase in temperature. At 14°C the reproductive behaviour was similar, both species needing over 2 months to mature. At 18°C, the rate of gonadal development of R. philippinarum was greater than that of R. decussatus. Nevertheless, the results of this study confirm that both species have adapted perfectly to the temperature conditions of the Galician Rias, though certain differences between the reproductive behaviour of these species were detected. R. philippinarum accumulates oocytes prior to their partial or total emission, while in the case of R. decussatus gametes are liberated continuously. In the early phases of its development, the gonad of R. philippinarum is highly heterogeneous in nature, with up to 3 reproductive states being present at the same time, while in R. decussatus gonadal development is much more uniform. Another major difference concerns the phenomenon of reabsorption, common in R. philippinarum but very rare in R. decussatus. These characteristics may well result in a greater reproductive activity in R. philippinarum than in R. decussatus, and a longer reproduction period in the former. They may also represent a certain advantage for the adaptation of the foreign species (R. philippinarum) over the native species (R. decussatus) to the temperature conditions of the Galician Rias

Patterns of spatial changes on demersal species in the Gulf of Cadiz and northern Alboran Sea

The Gulf of Cadiz (GoC) in the Atlantic Ocean and the northern Alboran Sea (AS) in the Mediterranean Sea are part of an extremely important oceanographic complex in terms of water exchange between the Atlantic and the Mediterranean through the Strait of Gibraltar. Besides its significant role as an ecological transition system, it is unknown whether regional and local envi ronmental drivers affect similarly species inhabiting these two adjacent and connected ecosystems. This study analyses the spatial shifts of representative demersal species and their response to the environmental and demographic drivers in these two regions, using information from two trawl surveys carried out in the GoC and in the AS from 1994 to 2015. Species distribution trends were observed in both basins. However, they were more evident in the GoC, where six out of eleven species presented temporal trends, than in the AS, where only two species displayed significant distribution changes. In both basins, these species showed geographic displacements towards the Strait of Gibraltar. Also, a high percentage of species presented significant differences in mean depth distribution on the two sides of the Strait of Gibraltar. Our study shows a general heterogeneity and independence in the drivers influencing species distributions in the two areas. GoC was highly influenced by both large- and regional-scale climate factors, which affected several species, while in AS the diversity of drivers was greater, with species density being the most common. This study provides a scientific basis for improving ecosystem-based management measures in these important transitional ecosystems.Postprint0,56

Impact of size and food concentration on clearance and ingestion rates in the clam Ruditapes decussates (Linnaeus, 1758)

The impact of food concentration (C) and water flow on the clearance (TA) and ingestion (TI) rates of the clam Ruditapes decussates (Linnaeus, 1758) was studied, using different-sized specimens. We found no relationship between C and TA, whereas there was a significant relationship between C and TI (TI = 24.757 + 0.576 C). The relationship between TA and the clams' live weight (PV) was also significant (TA = 4.292 PV0.683). A close relationship between PV and TI was found only when food availability (AD), a parameter that includes food concentration and flow, was constant. When it was not, the equation TI = 64.089 + 0.015 PV + 0.546 AD appears to explain 96.1% of TI variability.Se estudia el efecto de la concentración de alimento (C) y el flujo sobre las tasas de aclaramiento (TA) e ingestión (TI) de Ruditapes decussatus (Linnaeus, 1758) con ejemplares de diferentes tamaños. En esta especie no se observa relación entre C y TA, mientras que entre TI y C la relación es significativa: TI = 24,757 + 0,576 C. Igualmente es significativa la relación entre TA y el peso vivo (PV): TA = 4,292 PV0,683. PV y TI guardan una estrecha relación sólo en caso de que el alimento disponible (AD), variable que engloba la concentración de alimento y el flujo, se mantenga constante. En caso contrario, se propone la utilización de la ecuación TI = 64,089 + 0,015 PV + 0,546 AD que explica el 96,1 % de la variabilidad de TI.Instituto Español de OceanografíaVersión de editor

Dynamics of biochemical components, lipids classes and energy values on gonadal development of R.philippinarum associated with the temperature and ingestion rate

This study evaluates the effect of temperature, coupled with ingestion rate, on the dynamics of biochemical components and lipid classes in R. philippinarum. The data are discussed with regard to sexual development and energy balance. Experimental protocol developed in the present study used two groups of the clam R. philippinarum: L (temperatures of 14 °C and 18 °C) and H (temperatures of 18 °C and 22 °C). The intra-group ingestion level was similar, although the ingestion level of the clams in the group H was 2.4 times higher than group L. We observed that R. philippinarum conditioned at 18 °C (18L) shows higher protein content, furthermore an important loss of organic weight was observed after 48 days. In such a situation, the clams use their own reserves (carbohydrates and glycogen) for sexual development while in situations without food stress (positive energy balance) and low temperature (14 °C) an accumulation of reserves is produced. Strikingly dissimilar behaviour in biochemical composition was observed for the 18H and 22H treatments, both with a positive energy balance. Despite similar protein content, the highest levels of carbohydrates were observed at the lower temperature (18 °C). Glycogen was also higher for the 18 °C treatment, although the differences were significant only in the males. Although the total lipids in R. philippinarum showed no significant differences in any treatment, they became apparent and related to sex when considering the individual lipid classes. There was no variation in lipid classes in the males between the 14L and 22H treatments despite the large disparity in the degree of sexual development. However, in the females significant differences in lipid classes (phospholipids, triglycerides) were observed. The results of this study show that a positive energy balance permits R. philippinarum gonadal development and accumulation of reserves both in low and high temperature conditions. In low temperature situations, gonadal development is slower and the energy reserves are accumulated in the form of carbohydrates. When the clams are conditioned at high temperatures, gonadal development is fast and complete, carbohydrates are consumed and lipids are accumulated.Publicado

Population genetics of the Manila clam (Ruditapes philippinarum) introduced in North America and Europe

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Population and production parameters of the wedge clam Donax trunculus (Linnaeus, 1758) in intertidal areas on the southwest Spanish coast: Considerations in relation to protected areas

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Energy balance of the clam Ruditapes decussatus (Linnaeus, 1758)

The effect of food ingestion and clam size on absorption efficiency, absorption rate and oxygen consumption of the clam Ruditapes decussatus (L., 1758) was studied. Absorption efficiency (AE) was related to the ingestion rate (IR) following the non-lineal equation AE = 0.836 + e-0.64/IR (P 0.01; n = 26; r² = 0.321) No significant relationship as found between AE and clam live weight, whereas there was a relationship between absorption rate (AR) and IR, following the expression AR = 0.8248 IR - 0.0344 (P 0.001; n = 26; r² = 0.964) The maintenance food ration for a 2 g (live weight) clam was estimated as 1.528 J/h, equivalent to a daily food ration of 0.08 mg organic matter/g clam live weight.Se estudia el efecto de la ingestión de alimento y el tamaño de las almejas sobre la eficiencia de absorción, la tasa de absorción y el consumo de oxígeno de Ruditapes decussatus (L., 1758). La eficiencia de absorción (EA) se relaciona con la tasa de ingestión (TI) siguiendo el modelo no lineal EA = 0,836 + e-0,64/TI (P 0,01; n = 26; r² = 0,321) Entre EA y el peso vivo de las almejas no existe una relación significativa, mientras que sí la hay entre la tasa de absorción (TA) y TI, y responde a la ecuación TA = 0,8248 TI - 0,0344 (P 0,001; n = 26; r² = 0,964) La ración de mantenimiento de una almeja de 2 g de peso vivo es de 1,528 J/h, que se corresponde con una dieta diaria de 0,08 mg de materia orgánica por gramo de peso vivo.Instituto Español de Oceanografí

Growth of Octopus vulgaris (Cuvier, 1797) in tanks in the Ebro Delta (NE Spain): effects of temperature, salinity and culture density

To assess the possibility of O. vulgaris ongrowing using tanks or cages in the bays of the Ebro Delta, we performed several growth trials of common octopus held in tanks. Effects of environmental factors (temperature and salinity) and zootechnical aspects (culture density) were studied. The thermal ranges that defined positive growth periods in the bays of the Ebro Delta were 19.5ºC to 23ºC (spring-summer) and 23.5ºC to 12.3ºC (autumn-winter), the latter being the most suitable period for ongrowing. Salinity did not affect survival (100%) or growth within the range tested (34-29 psu), though feeding rates (AFR, SFR) were directly related to salinity. On the other hand, after 60 days, final culture density increased three-fold (D1: 12.36 → 44.37 kg m–3; D2: 24.13 → 67.76 kg m–3), with optimal survival results (>90%) for the two densities tested. Growth and feeding rates showed a slight inverse relationship with density. Finally, growth and feeding rates showed a clear dependence on temperature in the two experiments (density and salinity). Our results conclude that industrial production of O. vulgaris in tanks is promising: this system offers an alternative to cages and allows for a more exhaustive control of culture.Con el fin de evaluar la posibilidad de engorde de O. vulgaris en tanques o jaulas en las bahías del Delta del Ebro, se llevaron a cabo varias experiencias de crecimiento de individuos mantenidos en tanques. Se estudiaron tanto aspectos medioambientales (temperatura y salinidad) como zootécnicos (densidad de cultivo). Los rangos térmicos que definieron periodos positivos de crecimiento en las bahías del Delta del Ebro fueron: 19.5ºC-23ºC (primavera-verano) y 23.5ºC-12.3ºC (otoño-invierno), siendo este último el periodo más favorable para el engorde. La salinidad no afectó a la supervivencia o al crecimiento dentro del rango testado (34-29 psu), a pesar de que las tasas de alimentación (AFR, SFR) mantuviesen relación directa con la salinidad. Por otro lado, y transcurridos 60 días, observamos que la densidad de cultivo se multiplicó por tres (D1: 12.36 → 44.37 kg m–3; D2: 24.13 → 67.76 kg m–3), con resultados óptimos de supervivencia (>90%) bajo las dos condiciones probadas. Las tasas de crecimiento y alimentación mostraron una relación indirecta con la densidad de cultivo. Finalmente, se observó que tanto las tasas de crecimiento como las de alimentación presentan una clara dependencia de la temperatura en ambas experiencias (salinidad y densidad de cultivo). Nuestros resultados concluyen que la producción industrial de O. vulgaris en tanques es prometedora: este sistema ofrece una alternativa a las cajas y permite un control más exhaustivo del cultivo

Mutational Activation of ras Genes is Absent in Pediatric Osteosarcoma

Activation of ras oncogenes is found in human cancers; overall it is observed in 15% of all neoplasms. The purpose of this study was to assess the extent of involvement of ras oncogenes in osteosarcoma. Tumor samples from a series of 49 pediatric patients diagnosed with osteosarcoma and treated at our institution were evaluated. Paraffin-embedded tumor samples from diagnostic biopsies, from tumor en bloc resection tissue after neoadjuvant chemotherapy, and samples from metastases were examined in search of point mutations in H, K, and N-ras genes at codons 12 and 61 by means of polymerase chain reaction (PCR), slot-blotting, and radioactive labeled specific DNA probes. A total of 92 archival samples were studied. No point mutations activating these genes were found. These findings suggest that the activation by point mutations at codons 12 and 61 of the H, K, and N-ras genes does not play a role in the pathogenesis of human osteosarcoma. Since no point mutations in codons 12 and 61 were detected, it was not possible to establish any correlation between the ras genes and clinical or histologic finding

Assessment of Motor Activities of Daily Living:Spanish Cross-Cultural Adaptation, Reliability and Construct Validity of the DCDDaily-Q

[Abstract] The DCDDaily-Q is an instrument that aims to comprehensively assess motor performance in a broad range of activities of daily living (ADL) and to identify risk of Developmental Coordination Disorder (DCD) in children. The aim of this study was to cross-culturally adapt the DCDDaily-Q into European Spanish (DCDDaily-Q-ES) and to test its psychometric properties in Spanish 5 to 10 year old children. The DCDDaily-Q was translated and cross-culturally adapted into Spanish following international guidelines. Two-hundred and seventy-six parents of typically developing Spanish children completed the final version of the DCDDaily-Q-ES (M = 7.5 years, SD = 1.7; girls = 50%). Confirmatory Factor Analysis (CFA), internal consistency, and corrected item-total correlations were conducted to test construct validity, internal consistency, and homogeneity of the DCDDaily-Q-ES. The DCDDaily-Q-ES achieved good semantic, conceptual, and cultural equivalence. CFA supported construct validity of the DCDDaily-Q-ES. Reliability values were also good (Cronbach’s alpha = 0.703–0.843; corrected item-total correlations = 0.262–0.567). This is the first study to cross-culturally adapt and examine the DCDDaily-Q outside the Netherlands. The findings suggest that the DCDDaily-Q-ES is a reliable and valid measure to assess learning, participation, and performance in a broad range of ADL.Xunta de Galicia; ED481A-2018/15