, FIGUEROA VILLALOBOS, ELIAS GUSTAVO, FARIAS VEGA, CRISTIAN ALEX, Beltran, Jorge F., Belén, Lisandra Herrera, Lee-Estevez, Manuel, Villalobos, Elías Figueroa, Dumorné, Kelly, Farias, Jorge G.

Ca2+ is a key element in the sperm activation process of Salmo salar. However, the molecular mechanisms by which this ion enters the sperm cell have been poorly studied. In this study, we examined, for the first time, the role of the voltage-gated T-type Ca2+ channel in the activation of sperm motility of Salmo salar. Using an in vitro inhibition assay, a significant decrease in total and progressive motility (P < 0.0001) was observed in Salmo salar sperm when they were treated with NNC-55-0396, a highly selective blocker. The in silico analysis showed that this blocker is docked with a strong affinity for the pore of the voltage-gated T-type calcium channel suggesting the blocking of Ca2+ ions. The results show that the T-type voltage-gated Ca2+ channel is key to sperm motility in Salmo salar. © 2020 Elsevier B.V., All rights reserved.

, FIGUEROA VILLALOBOS, ELIAS GUSTAVO, VALDEBENITO ISLER, NEMESIO IVAN, Valdebenito, Iván, Villalobos, Elías Figueroa, Sandoval-Vargas, Leydy Y., Contreras-Mellado, Pablo, Sánchez-Caamaño, Juan Carlos, Farias, Jorge G., Risopatron, Jennie

There is no information about the characteristics of early cleavage in the Patagonian blennie (Eleginops maclovinus), which can be used as a diagnostic tool for embryo quality. The purpose of this investigation, therefore, was to characterize the first blastomeres of E. maclovinus morphologically. Of a 'pool' of incubated eggs at 10.7 ± 0.5°C, 100 microphotographs of blastodiscs were extracted at different incubation periods from 0.25 to 5 h after fertilization and analyzed. Blastodiscs taken at 3.5, 4.0 and 5.0 h were characterized and classified into symmetric or asymmetric groups according to their morphology. The proportions of length (L) and width (W) of each blastomere were determined to establish its symmetry. Additionally, 20 microphotographs of blastodiscs of normal appearance were analyzed morphologically (control blastodisc: CB) and compared other blastodiscs (4.0 and 5.0 h). The results showed that before fertilization oocytes presented a somehow turgid aspect (maximum average diameter of 987 ± 41 Am) and after fertilization and hydration, their diameter increased to 1001.5 ± 11 Am (but not statistically significant) and presented a spherical shape. First cleavage ends after 3.5 h of development, forming two blastomeres 467 ± 45 ?m length (L) and 328 ± 21 ?m width (W) with a L/W ratio of 1.43 ± 0.19. The second cleavage ends after development at 4.5 h forming four blastomeres 238 ± 65 ?m length and 227 ± 65 ?m width with a ratio L/W of 1.06 ± 0.09. Five categories were identified during the blastomere characterization: 70% normal or symmetric; 8% with odd numbers of blastomeres; 6% unequal; 6% 'pie shaped' and 10% amorphous. © 2019 Elsevier B.V., All rights reserved.

, FIGUEROA VILLALOBOS, ELIAS GUSTAVO, VALDEBENITO ISLER, NEMESIO IVAN, Dumorné, Kelly, Valdebenito, Iván, Risopatron, Jennie, Villalobos, Elías Figueroa, Díaz, Rommy, Farias, Jorge G.

In this study, the morphology and ultrastructure of Genypterus blacodes spermatozoa were characterized through scanning and transmission electron microscopy. Findings revealed that the G. blacodes spermatozoa can be differentiated into three major parts: a spherical head without an acrosome (typical for externally fertilizing fish), a short mid-piece, and a long flagellum. The mean length of the spermatozoa was 57.6 ± 6.08 ?m, with flagella accounting for 56.2 ± 7.2 ?m. The head was 1.47 ± 0.2 ?m long, and 0.89 ± 0.06 ?m wide. The mid-piece had a total dimension of 0.72 ± 0.16 ?m, and was 0.31 ± 0.02 ?m in length and 0.6 ± 0.05 ?m in width. It was located lateral to the nucleus and contained 4 or 5 spherical mitochondria. The mitochondria were separated from the axoneme by a cytoplasmic canal. The main piece of the flagellum had short irregular side-fins, and the axoneme was composed of the typical 9 + 2 microtubular doublet structure enclosed by a cell membrane. The present study reveals that G. blacodes sperm can be categorized as a primitive type. This study is the first to provide comprehensive details on the morphology and ultrastructure of spermatozoa in G. blacodes. © 2018 Elsevier B.V., All rights reserved.