Thermal tolerance of the male freshwater prawn Cryphiops caementarius exposed to different acclimation temperatures.

The variation in water temperature influences metabolic and biochemical processes in ectothermic organisms, affecting development, behavior, and thermal responses. We conducted laboratory experiments based on different acclimation temperatures to determine the thermal tolerance in male specimens of the freshwater prawn Cryphiops caementarius. During 30 days, male prawns were exposed to acclimation temperatures of 19 °C (control), 24 °C, and 28 °C treatments. The Critical Thermal Maxima (CTMax) values at these acclimation temperatures were 33.42 °C, 34.92 °C, and 36.80 °C; whereas values for the Critical Thermal Minimum (CTMin) were 9.38 °C, 10.57 °C, and 13.88 °C. All acclimation temperature treatments had a positive effect (P < 0.05) on CTMax and CTMin, with high and significant correlations (CTMax: r = 0.992, P < 0.01; CTMin: r = 0.946, P < 0.01). The area of the thermal tolerance polygon over the three acclimation temperatures was 211.32 °C2 and the acclimation response rate values were high (CTMax from 0.30 to 0.47; CTMin from 0.24 to 0.83) but similar to those from other tropical crustacean species. These results demonstrate that adult males of the freshwater prawn C. caementarius can tolerate extreme water temperatures through a thermal plasticity response, which could be advantageous during a global warming scenario.

Performance comparison of gel and capillary electrophoresis-based microsatellite genotyping strategies in a population research and kinship testing framework.

OBJECTIVE: The advancement of molecular techniques in an era in which high-throughput sequencing has revolutionized biology renders old-fashioned alternatives to high-throughput methods obsolete. Such advanced molecular techniques, however, are not yet accessible to economically disadvantaged region-based laboratories that still obtain DNA profiles using gel-based techniques. To explore whether cost-efficient techniques can produce results that are as robust as those obtained using high-throughput methods, we compared the performance of polyacrylamide gel electrophoresis (PAGE)- and capillary electrophoresis (CE)-derived genomic data in estimating genetic diversity and inferring relatedness using 70 individuals of fine flounder (Paralichthys adspersus) selected from a hatchery population and genotyped for five microsatellite loci. RESULTS: Here, we show that PAGE- and CE-derived genomic datasets yield comparable genetic diversity levels regarding allelic diversity measures and heterozygosity. However, relatedness inferred from each dataset showed that the categorization of dyads in the different relationship categories strongly differed. This suggests that while scientists can reliably use PAGE-derived genomic data to estimate genetic diversity, they cannot use the same for parentage testing. The findings could help laboratories committed to population research not be discouraged from using the PAGE system if high-throughput technologies are unavailable and the method is adequate to address the biological question.

The complete mitochondrial genome of the fine flounder Paralichthys adspersus revealed by next-generation sequencing.

The complete mitochondrial genome of the fine flounder Paralichthys adspersus, was determined for the first time through Next Generation Sequencing (NGS) approach. The mitogenome (GenBank accession no. MW288827) has 17,060 bp in length and consisted of the well-known 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and the control region. The overall nucleotide composition of the whole mitogenome was A: 27.5%, C: 29.5%, G: 17.1%, and T: 25.9%. Phylogenetic analyses based on 12 protein-coding genes clustered P. adspersus in the monophyletic Paralichthyidae clade, showing the closest phylogenetic relationship with its congeneric species P. olivaceus.

Trabajos originales Preferencia termal de machos adultos de Cryphiops caementarius previamente aclimatados a diferen- tes temperaturas / Thermal preference of adult males of Cryphiops caementarius previously acclimated at different temperatures

Resumen El objetivo fue determinar la preferencia termal de machos adultos de Cryphiops caementarius previamente aclimatados a diferentes temperaturas. Los camarones se colectaron del río Pativilca. En laboratorio, los camarones se aclimataron durante 30 días en nueve acuarios, cada uno con 10 recipientes circulares. En cada recipiente hubo un camarón (10 por acuario). Las temperaturas de aclimatación fueron de 19, 24 y 28 °C. El sistema de gradiente de temperatura (12 a 33 °C) fue una canaleta de PVC (3 m de longitud y 10 cm de profundidad) con 18 compartimentos. En un extremo de la canaleta se colocaron termorreguladores sumergibles (100W) y en el otro extremo, bolsas con hidrogel congeladas. La preferencia termal se determinó por el método agudo y las pruebas se realizaron entre las 08:00 y 14:00 h. Los camarones aclimatados a 24 °C se desplazaron a compartimentos cuyas temperaturas fueron más altas que la temperatura de aclimatación. Los camarones aclimatados a 24 °C se desplazaron a compartimentos cuyas temperaturas fueron alrededor de la temperatura de aclimatación. Los camarones aclimatados a 28 °C se desplazaron a compartimentos donde las temperaturas fueron más bajas que aquella de aclimatación. La preferencia termal de los camarones aclimatados a 19 °C fue de 22.7 °C, y la de los aclimatados a 24 °C fue de 24.8 °C, ambos sin diferencias significativas (p>0.05). En cambio, en los aclimatados a 28°C fue de 21.1 °C, que solo difirió (p<0.05) con los aclimatados a 19 °C. La preferencia termal final fue de 24.5 °C.

Abstract In this work, we establish the thermal preference of Cryphiops caementarius adult males, previously acclimated at different temperatures. Shrimp were collected from the Pativilca River. In the laboratory, shrimp were acclimated for 30 days in nine aquariums, each with 10 circular containers. In each container, there was a shrimp (10 per aquarium). Acclimation temperatures were 19, 24 and 28 °C. The gradient temperature system (12 to 33 °C) consisted for a PVC gutter (3 m long and 10 cm deep) with 18 compartments. Submersible thermoregulators (100W) were placed at one end of the gutter and the other end, frozen hydrogel bags. The thermal preference was determined by the acute method and the tests were performed between 08:00 and 14:00 h. Shrimp acclimated at 24 °C moved to compartments whose temperatures were higher than the acclimation temperature. Shrimp acclimated at 24 °C moved to compartments whose temperatures were around the acclimation temperature. Shrimp acclimated at 28 °C moved to compartments where temperatures were lower than acclimation. The thermal preference of acclimated shrimp at 19 °C was 22.7 °C, and those acclimated at 24 °C were 24.8 °C, both without significant differences (p>0.05). On the other hand, in acclimated ones at 28 °C it was 21.1 °C, which only differed (p<0.05) with those acclimated at 19 °C. The final thermal preference was 24.5 °C.