Morfometría geométrica aplicada al estudio evolutivo de los espermatozoides y su relación con determinantes de la fertilidad en roedores

Tesis doctoral inédita leída en la Universidad Autónoma, Facultad de Ciencias, Departamento de Biología. Fecha de lectura: 07-07-201

Geometric morphometrics of rodent sperm head shape

Mammalian spermatozoa, particularly those of rodent species, are extremely complex cells and differ greatly in form and dimensions. Thus, characterization of sperm size and, particularly, sperm shape represents a major challenge. No consensus exists on a method to objectively assess size and shape of spermatozoa. In this study we apply the principles of geometric morphometrics to analyze rodent sperm head morphology and compare them with two traditional morphometry methods, that is, measurements of linear dimensions and dimensions-derived parameters calculated using formulae employed in sperm morphometry assessments. Our results show that geometric morphometrics clearly identifies shape differences among rodent spermatozoa. It is also capable of discriminating between size and shape and to analyze these two variables separately. Thus, it provides an accurate method to assess sperm head shape. Furthermore, it can identify which sperm morphology traits differ between species, such as the protrusion or retraction of the base of the head, the orientation and relative position of the site of flagellum insertion, the degree of curvature of the hook, and other distinct anatomical features and appendices. We envisage that the use of geometric morphometrics may have a major impact on future studies focused on the characterization of sperm head formation, diversity of sperm head shape among species (and underlying evolutionary forces), the effects of reprotoxicants on changes in cell shape, and phenotyping of genetically-modified individuals. © 2013 Varea Sánchez et al.This work was supported by the Spanish Ministry of Economy and Competitiveness.Peer Reviewe

Biological well-being during the “economic miracle” in Spain: Height, weight and body mass index of conscripts in the city of Madrid, 1955–1974

Typifying historical populations using anthropometric indicators such as height, BMI and weight allows for an analysis of the prevalence of obesity and malnutrition. This study evaluates secular changes in height, weight and body mass for men cohorts at 21 years old, born between 1934 and 1954 who were called up between 1955 and 1974, in the city of Madrid, Spain. In this study we prove the hypothesis that anthropometric variables increase thanks to improvement in diet and significant investments in hygiene and health infrastructure during the 1960s. The results of our analysis show a positive secular change in the trends for height (an increase of 4.67 cm), weight (6.400 kg) and BMI (0.90 Kg/m2 ), the result of a recovery in standards of living following the war and the autarchy of the 1940s. We also observed a slight trend towards obesity and a reduction in underweight categories at the end of the period is also observed. In conclusion, the secular trends of anthropometric variables in the city of Madrid reflect the recovery of living standards after the deterioration of the nutritional status suffered during the Spanish Civil War (1936–1939) and the deprivation of the autarchic perio

Sexual selection on protamine and transition nuclear protein expression in mouse species

Post-copulatory sexual selection in the form of sperm competition is known to influence the evolution of male reproductive proteins in mammals. The relationship between sperm competition and regulatory evolution, however, remains to be explored. Protamines and transition nuclear proteins are involved in the condensation of sperm chromatin and are expected to affect the shape of the sperm head. A hydrodynamically efficient head allows for fast swimming velocity and, therefore, more competitive sperm. Previous comparative studies in rodents have documented a significant association between the level of sperm competition (as measured by relative testes mass) and DNA sequence evolution in both the coding and promoter sequences of protamine 2. Here,we investigate the influence of sexual selection on protamine and transition nuclear protein mRNA expression in the testes of eight mouse species that differ widely in levels of sperm competition.We also examined the relationship between relative gene expression levels and sperm head shape, assessed using geometric morphometrics. We found that species with higher levels of sperm competition express less protamine 2 in relation to protamine 1 and transition nuclear proteins. Moreover, therewas a significant association between relative protamine 2 expression and sperm head shape. Reduction in the relative abundance of protamine 2 may increase the competitive ability of sperm in mice, possibly by affecting sperm head shape. Changes in gene regulatory sequences thus seem to be the basis of the evolutionary response to sexual selection in these proteins. © 2014 The Author(s) Published by the Royal Society. All rights reserved.This work was supported by the Spanish Ministry of Economy and Competitiveness (grant no. CGL2011-26341)Peer Reviewe

Performance of rodent spermatozoa over time is enhanced by increased ATP concentrations: The role of sperm competition

© 2015 by the Society for the Study of Reproduction, Inc. Sperm viability, acrosome integrity, motility, and swimming velocity are determinants of male fertility and exhibit an extreme degree of variation among closely related species. Many of these sperm parameters are associated with sperm ATP content, which has led to predictions of trade-offs between ATP content and sperm motility and velocity. Selective pressures imposed by sperm competition have been proposed as evolutionary causes of this pattern of diversity in sperm traits. Here, we examine variation in sperm viability, acrosome integrity, motility, swimming velocity, and ATP content over time, among 18 species of closely related muroid rodents, to address the following questions: (a) Do sperm from closely related species vary in ATP content after a period of incubation? (b) Are these differences in ATP levels related to differences in other sperm traits? (c) Are differences in ATP content and sperm performance over time explained by the levels of sperm competition in these species? Our results revealed a high degree of interspecific variability in changes in sperm ATP content, acrosome integrity, sperm motility and swimming velocity over time. Additionally, species with high sperm competition levels were able to maintain higher levels of sperm motility and faster sperm swimming velocity when they were incubated under conditions that support sperm survival. Furthermore, we show that the maintenance of such levels of sperm performance is correlated with the ability of sperm to sustain high concentrations of intracellular ATP over time. Thus, sperm competition may have an important role maximizing sperm metabolism and performance and, ultimately, the fertilizing capacity of spermatozoa.Peer Reviewe

Is male reproductive senescence minimised in Mus species with high levels of sperm competition?

Sperm competition, an evolutionary process in which the spermatozoa of two or more males compete for the fertilization of the same ovum, gives rise to several morphological and physiological adaptations. Generally, high levels of sperm competition enhance sperm function. In contrast, advanced age is known to lead to reproductive senescence, including a general decline in sperm function. Sperm competition and advanced age may thus have opposing effects on sperm function. Here, we tested the hypothesis that the increase in sperm function in species experiencing high levels of sperm competition will counteract the negative effects of advanced age. We measured a comprehensive set of reproductive traits in young and old males in three species of mice of the genus Mus, which differ greatly in their levels of sperm competition. Our prediction was that the expression of reproductive senescence would be highest in the species with low levels of sperm competition and lowest in the species with high levels of sperm competition. Surprisingly, we did not find a strong signal of reproductive senescence in any of the three Mus species. Overall, our results did not clearly support our hypothesis that high levels of sperm competition minimize the negative effects of ageing on sperm function

Experiencias en el desarrollo del Plan de Coordinación Docente del Grado en Ingeniería Informática

Una buena coordinación del equipo docente implicado en cualquier titulación es indispensable para la correcta consecución, por parte de los estudiantes, de las competencias específicas y transversales recogidas en su plan de estudios. Dos años después de la implantación, por inmersión, de la nueva titulación de Grado en Ingeniería Informática adaptada al Espacio Europeo de Educación Superior (EEES), compartimos en este trabajo nuestras experiencias y reflexiones en la puesta en marcha del Plan de Coordinación que había sido definido. En particular, concretamos las acciones de coordinación llevadas a cabo, haciendo hincapié en las herramientas de las que nos hemos servido. También identificamos las fortalezas y debilidades detectadas, así como las dificultades encontradas, proponiendo líneas de actuación futuras.A good coordination of the teaching staff involved in a degree is essential for the achievement by students of the transversal and generic skills considered in the corresponding syllabus. Two years after the complete implantation of the new degree in Computing, which has been adapted to the European Higher Education Area (EHEA), in this paper we detail our experiences and thoughts on the implementation of the Coordination Plan initially proposed. In particular, we focus on the coordination tasks carried out and the tools that we have used. We also identify the strengths and weaknesses observed and the handicaps found. Finally, we propose some lines of future work

A High Dynamic Range ASIC for Time of Flight PET with monolithic crystals

The HRFlexToT is a 16-channel ASIC for SiPM anode readout designed for Positron Emission Tomography (PET) applications that features high dynamic range (>8 bits), low input impedance, common cathode connection, high speed and low power (~3.5 mW/ch). The ASIC has been manufactured using XFAB 0.18 mm CMOS technology. The main characteristics of the HRFlexToT, compared to its predecessor, are a new energy measurement readout providing a linear Time Over Threshold (ToT) with an extended dynamic range, lower power consumption and better timing response. Initial measurements show a linearity error below 3%. Single Photon Time Resolution (SPTR) measurements performed using a Hamamatsu MPPC S13360-3050CS (3x3 mm2 pixel, 50 umm cell) shows 30% improvement with respect to the previous version of the ASIC, setting this specification in the order of 141 ps FWHM and reducing 3 times power consumption. It is important to highlight that an SPTR of 141 ps FWHM is, according to the best of our knowledge, the best resolution achieved so far for this sensor. Coincidence Time Resolution (CTR) measurements are expected to be performed during 2018