lunes, 18 de julio de 2016
Marina Morini defiende su Tesis Doctoral
El viernes 15 nuestra compañera Marina Morini defendió su Tesis Doctoral titulada: “Molecular approaches related to the European eel (Anguilla anguilla) reproductive process”, que ha sido codirigida por Juan F. Asturiano y David S. Peñaranda, y financiada fundamentalmente por el Proyecto PRO-EEL (UE), el proyecto REPRO-TEMP (MINECO) y la Acción COST AQUAGAMETE.
El Dr. José Miguel Cerdá Reverter (del Instituto de Acuicultura de Torre de la Sal, CSIC) actuó como Presidente del Tribunal, el Dr. Ibon Cancio (de la Universidad del País Vasco/Euskal Herriko Unibertsitatea) fue el Secretario, y la Dra. Salima Aroua (de la Université du Havre, Francia) fue el tercer miembro del mismo.
Al acabar el acto de defensa, el Tribunal le concedió la máxima calificación, Sobresaliente Cum Laude. Enhorabuena Dra. Morini!
El documento final es un compendio de 4 artículos:
● Temperature modulates the testis steroidogenesis in European eel
Peñaranda et al., 2016. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
● Expression of nuclear and membrane estrogen receptors in the European eel throughout spermatogenesis
Morini et al., en revisión en Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
● Nuclear and membrane progestin receptors in the European eel: characterization and expression in vivo through spermatogenesis
Morini et al., en revisión en PloS ONE
● Transcript levels of the soluble sperm factor protein phospholipase C zeta 1 (PLCζ1) increase through induced spermatogenesis in European eel
Morini et al., 2015. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
con una introducción y una discusión general. El pdf con el texto completo esta disponible on-line en: .
The European eel (Anguilla anguilla, L., 1758) population is in dramatic decline, so much so that this species has been listed as “Critically Endangered” on the Red List of Threatened Species, by the International Union for Conservation of Nature (IUCN). The European eel has a complex life cycle, with sexual maturation blocked in the absence of the reproductive oceanic migration, and an inability to mature in captivity without the administration of hormonal treatments. Even though experimental maturation induces gamete production of both sexes, the fertilization results in infertile eggs, unviable embryos and larvae, which die within a few days of hatching. Therefore, understanding the eel reproductive physiology during maturation is very important if we want to recover the wild eel population. Furthermore, due to its phylogenetic position, representative of a basal group of teleosts, the Elopomorphs, the Anguilla species may provide insights into ancestral regulatory physiology processes of reproduction in teleosts, the largest group of vertebrates.
In this thesis, characterization, phylogeny and synteny analyses have given us new insight into the evolutionary history of the reproductive process in vertebrates. The European eel possesses five membrane (mPRs) and two nuclear (nPR or pgrs) progestin receptors. Eel mPRs clustered in two major monophyletic groups. Phylogeny analysis of vertebrate nPRs and PLCζ1 (sperm specific protein) places both eel PLCζ1 and nPR sequences at the base of the teleost clade, which is consistent with the basal position of elopomorphs in the phylogeny of teleosts. To further resolve the origin of the duplicated eel nPRs, synteny analyses of the nPR neighboring genes in several vertebrate genomes were performed. Phylogeny and synteny analyses allowed us to propose the hypothesis that eel duplicated nPRs originated from the 3R.
In order to gain a better understanding of the role of the genes implicated in eel reproduction, analyses of their regulation during experimental maturation were carried out. The change in salinity induced parallel increases in E2 plasma and nuclear estrogen receptor expression levels, revealing a stimulatory effect of salinity on the E2 signalling pathway along the BPG axis, leading to a control of spermatogonial stem cell renewal. Brain and pituitary estrogen receptors may then mediate the stimulation of androgens and steroidogenic enzymes linked to androgen synthesis. Androgen synthesis is not dependent on temperature, but further maturation requires higher temperatures to induce a change in the steroidogenic pathway towards estrogen and progestin synthesis. This is consistent with our studies on estrogen and progestin receptors. In the testis, progestin seems to regulate meiosis through membrane and nuclear progestin receptors, and final sperm maturation seems to be controlled by both estrogen and progestin through the estrogen and progestin membrane receptors. Finally, eel sperm-specific PLCζ1 seems to have an important function in spermatozoa by inducing egg activation and temperature may play a role in its regulation, especially during the process of spermiogenesis.
This thesis attempts to evaluate the physiological function of the genes involved in eel reproduction during spermatogenesis, and demonstrates that salinity and temperature play crucial roles in the sexual maturation of the male European eel.