Global impact of diet and temperature over aquaculture of Octopus vulgaris paralarvae from a transcriptomic approach

Common octopus, Octopus vulgaris, is an economically important cephalopod species. However, its rearing under captivity is currently challenged by massive mortalities previous to their juvenile stage due to nutritional and environmental factors. Dissecting the genetic basis and regulatory mechanism behind this mortality requires genomic background knowledge. A transcriptomic sequencing of 10 dph octopus paralarvae from different experimental conditions was constructed via RNA-seq. A total of 613,767,530 raw reads were filtered and de novo assembled into 363,527 contigs of which 82,513 were annotated in UniProt carrying also their GO and KEGG information. Differential gene expression analysis was carried out on paralarvae reared under different diet regimes and temperatures, also including wild paralarvae. Genes related to lipid metabolism exhibited higher transcriptional levels in individuals whose diet includes crustacean zoeas, which had an impact over their development and immune response capability. High temperature induces acclimation processes at the time that increase metabolic demands and oxidative stress. Wild individuals show an expression profile unexpectedly similar to Artemia fed individuals. Proteomic results support the hypothesis revealed by transcriptional analysis. The comparative study of the O. vulgaris transcriptomic profiles allowed the identification of genes that deserve to be further studied as candidates for biomarkers of development and health. The results obtained here on the transcriptional variations of genes caused by diet and temperature will provide new perspectives in understanding the molecular mechanisms behind nutritional and temperature requirements of common octopus that will open new opportunities to deepen in paralarvae rearing requirements.Versión del edito

Antarctic surface reflectivity calculations and measurements from the ANITA-4 and HiCal-2 experiments

The balloon-borne HiCal radio-frequency (RF) transmitter, in concert with the ANITA radio-frequency receiver array, is designed to measure the Antarctic surface reflectivity in the RF wavelength regime. The amplitude of surface-reflected transmissions from HiCal, registered as triggered events by ANITA, can be compared with the direct transmissions preceding them by O ( 10 ) microseconds, to infer the surface power reflection coefficient R . The first HiCal mission (HiCal-1, Jan. 2015) yielded a sample of 100 such pairs, resulting in estimates of R at highly glancing angles (i.e., zenith angles approaching 90°), with measured reflectivity for those events which exceeded extant calculations [P. W. Gorham et al., Journal of Astronomical Instrumentation, 1740002 (2017)]. The HiCal-2 experiment, flying from December 2016–January 2017, provided an improvement by nearly 2 orders of magnitude in our event statistics, allowing a considerably more precise mapping of the reflectivity over a wider range of incidence angles. We find general agreement between the HiCal-2 reflectivity results and those obtained with the earlier HiCal-1 mission, as well as estimates from Solar reflections in the radio-frequency regime [D. Z. Besson et al., Radio Sci. 50, 1 (2015)]. In parallel, our calculations of expected reflectivity have matured; herein, we use a plane-wave expansion to estimate the reflectivity R from both a flat, smooth surface (and, in so doing, recover the Fresnel reflectivity equations) and also a curved surface. Multiplying our flat-smooth reflectivity by improved Earth curvature and surface roughness corrections now provides significantly better agreement between theory and the HiCal-2 measurements

Gesture human-computer interface for command and control

info:eu-repo/semantics/publishedVersio

Who are you? Identification of zooplankton species in the Ria de Vigo

In the last years, the marine aquaculture research group of the Oceanographic Center in Vigo is endeavoured with completing the life cycle of both, the European hake (Merluccius merluccius) and the Octopus (Octopus vulgaris) using different approaches. One identified bottlenecks for both species is the development stages of larvae and paralarvae which is probably related to nutrition. More research in this field is a key issue to overcome many culture problems. As far as we know, feeding larvae/paralarvae with wild zooplankton improves significantly their growth rate and survival. There are two key issues in this research to identify prey preferences for hakes and octopuses, first, to accomplish the molecular identification of zooplankton species present in Ría de Vigo and the second one, the use the sequences obtained to design specific primers for each species and apply them to identify the species present in the stomachs of hake larvae and Octopus paralarvae. The main goal of this research is two identify the natural zooplankton preys from Ría de Vigo using a molecular approach

Looking inside the eggs: the lipid droplet of the European hake

European hake is a species of great economic interest. In the aquaculture facilities of the IEO in Vigo there is the only European hake stock in captivity (Iglesias et al. 2010). One of the indicators of spawning quality is the proportion of larvae with the lipid droplet properly adhered to the membrane (ALD). The larvae non-ALD cannot consume the lipid droplet and die even though they feed on prey (Iglesias et al, 2013). The goal of this work was to determine how the lipid drop is adhered to the embryo