Eduardo R S Roldan

Eduardo R S Roldan
The National Museum of Natural Sciences · Department of Biodiversity and Evolutionary Biology

BA (Philosophy) BVetSci (DVM) PhD (Natural Sciences)

About

273
Publications
45,640
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Introduction
Eduardo Roldan, BA (Philosophy), DVM, PhD (Natural Sciences). Research Professor at the Spanish Research Council in Madrid. Fellow, Royal Academy of Veterinary Sciences. Currently working on human and animal reproduction focusing on evolution of reproductive systems, determinants of fertility, development of male fertility assessments tests and ARTs.

Publications

Publications (273)
Article
Full-text available
Ejaculate quality can be regarded as multifactorial, with nutrition being a factor that could directly influence sperm parameters. The present study aimed to evaluate seminal quality associated with seasonal fat-soluble vitamin supplementation of boars. Seven sexually mature boars were randomly allotted to one of the three groups, and fed one of th...
Preprint
In mammals, sperm acquire fertilization ability after a series of physiological and biochemical changes, collectively known as capacitation, that occur inside the female reproductive tract. In addition to other requirements, sperm bioenergetic metabolism has been identified as fundamental component in the acquisition of the capacitated status. Mamm...
Article
Full-text available
Assessments of sperm performance are valuable tools for the analysis of sperm fertilizing potential and to understand determinants of male fertility. Hamster species constitute important animal models because they produce sperm cells in high quantities and of high quality. Sexual selection over evolutionary time in these species seems to have resul...
Article
Full-text available
Mammalian sperm differ widely in sperm morphology, and several explanations have been presented to account for this diversity. Less is known about variation in sperm physiology and cellular processes that can give sperm cells an advantage when competing to fertilize oocytes. Capacitation of spermatozoa, a process essential for mammalian fertilizati...
Article
Full-text available
Post-copulatory sexual selection is thought to influence the evolution of genes involved in reproduction. However, the detection of straightforward effects has been proven difficult due to the complexity and diversity of reproductive landscapes found in different taxa. Here we compare the possible effect of relative testes mass as a sperm competiti...
Article
Full-text available
The aim was to determine the relationship between kinematic parameters of boar spermatozoa and fertility rates of sow, as well as to assess the effect of sperm clusters on the fertility capacity of the ejaculate. Semen samples were collected from 11 sexually mature boars. Samples were analyzed by an ISAS®v1 CASA-Mot system for eight kinematic param...
Article
The spermatozoon is a highly differentiated and polarized cell, with two main structures: the head, containing a haploid nucleus and the acrosomal exocytotic granule, and the flagellum, which generates energy and propels the cell; both structures are connected by the neck. The sperm's main aim is to participate in fertilization, thus activating dev...
Article
Full-text available
The aim of the study was to compare the morphometric features of sperm head size and shape from the Pietrain line and the Duroc × Pietrain boar crossbred terminal lines, and to evaluate their relationship with reproductive success after artificial insemination of sows produced from crossbreeding the York, Landrace and Pietrain breeds. Semen samples...
Article
Full-text available
Knowledge of factors affecting semen quality could be of great importance for the collection and preservation of semen from threatened animals. To assess the effect of seasonality, sperm parameters and testosterone levels were examined throughout the year and compared with the distribution of conceptions. Cuvier’s gazelle showed higher sperm quanti...
Article
Full-text available
There has been very limited use of computer assisted semen analysis (CASA) to evaluate reptile sperm. The aim of this study was to examine sperm kinematic variables in American crocodile (Crocodylus acutus) semen samples and to assess whether sperm subpopula-tions could be characterized. Eight ejaculates (two ejaculates/male) from four sexually mat...
Conference Paper
Abstract. 12th Biennial Meeting of the Association for Applied Animal Andrology; scheduled for Bologna, Italy on June 26–28, 2020. Published as Conference Proceedings in Animal Reproduction Science.
Article
Full-text available
Much can be gained from the comprehensive study of a biological system. Based on what is known as Mayr's proximate-ultimate causation and the subsequent expansion to Tinbergen's four questions, biological traits can be understood by taking into account different approximations that try to explain mechanisms, development, adaptive significance or ph...
Article
Full-text available
The ejaculate is heterogenous and sperm sub-populations with different kinematic patterns can be identified in various species. Nevertheless, although these sub-populations are statistically well defined, the statistical differences are not always relevant. The aim of the present study was to characterize kinematic sub-populations in sperm from two...
Article
Full-text available
Background: Cysteine-RIch Secretory Proteins (CRISP) are expressed in the reproductive tract of mammalian males and are involved in fertilization and related processes. Due to their important role in sperm performance and sperm-egg interaction, these genes are likely to be exposed to strong selective pressures, including postcopulatory sexual selec...
Article
Full-text available
Sperm differentiation encompasses a complex sequence of morphological changes that takes place in the seminiferous epithelium. In this process, haploid round spermatids undergo substantial structural and functional alterations, resulting in highly polarized sperm. Hallmark changes during the differentiation process include the formation of new orga...
Article
Full-text available
Paternal environmental perturbations, including cocaine intake, can affect the development and behavior of the offspring through epigenetic inheritance. However, the mechanism by which cocaine alters the male germ cells epigenome is almost unexplored. Here, we report that cocaine-treated male mice showed alterations on specific histone post-transla...
Article
Spermatozoa are diverse in form and function and these differences impact on their fertilizing capacity. Because of considerable inter-male and inter-species differences in sperm traits, assessments of sperm quality demand that we consider variations at different levels. We should thus pay attention not only to average values but also intra- and in...
Article
Sperm competition is a powerful selective force that has influenced many reproductive traits in males and females although additional evolutionary explanations may help to understand the diversity of mammalian reproduction. Sperm morphology varies considerably in mammals with extreme examples in several rodent lineages in which a wide range of size...
Article
Semen quality assessment requires accurate, reliable and objective methods for examination of sperm variables including sperm motility. For preparation of semen samples for artificial insemination, as a genetic resource, samples that are used for insemination need to have the capacity to result in a highly acceptable fertility rate. Several methods...
Article
Full-text available
Dogs have undergone an intensive artificial selection process ever since the beginning of their relationship with humans. As a consequence, a wide variety of well‐defined breeds exist today. Due to the enormous variation in dog phenotypes and the unlikely chance of gene exchange between them, the question arises as to whether they should still be r...
Article
Even though knowledge in sperm cryopreservation of endangered felids advanced in recent years, very little is known about suitable protocols to cryopreserve sperm from Leopardus geoffroyi (LG). In the present study, sperm obtained by electroejaculation from 5 different males were cryopreserved in either a Tes-Tris- or a lactose-based diluent (Gañan...
Article
Full-text available
On the occasion of the XIIIth International Symposium on Spermatology held from 9 to 13 May 2018 in Stockholm (Sweden), participants (guest speakers and audience) collectively felt the need to make a public statement on the general issue of male reproductive health. Our intention is to raise awareness of what we believe is a neglected area of resea...
Article
Full-text available
ATP supply is essential for sperm performance and increases in ATP content coevolve with enhanced sperm swimming velocity as a response to sperm competition in rodents. ATP content is the balance between production and consumption but, although ATP production has received much attention, little is known about ATP consumption. The rate of ATP consum...
Article
Full-text available
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, includi...
Article
Full-text available
A broad link exists between nucleotide substitutions in the mitochondrial genome (mtDNA) and a range of metabolic pathologies, but the exploration of the effect of specific mtDNA genotypes is on-going. Mitochondrial DNA mutations are of particular relevance for reproductive traits, because they are expected to have profound effects on male specific...
Article
Full-text available
Sexual selection is the pervasive force underlying the dramatic divergence of sperm form and function. Although it has been demonstrated that testis gene expression evolves rapidly, exploration of the proteomic basis of sperm diversity is in its infancy. We have employed a whole-cell proteomics approach to characterize sperm divergence among closel...
Article
Full-text available
Females of many iteroparous species face trade-offs between producing one or multiple broods per reproductive season, and over fertilizing broods with sperm from the same or different mates. Both trade-offs might be affected by the availability of males (i.e. absence/presence of males) and the timing and duration of male encounters. Here, we experi...
Article
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Rodents have spermatozoa with features not seen in other species. Sperm heads in many rodent species bear one or more apical extensions, known as "hook(s)". The process by which hooks have evolved, together with their adaptive significance, are still controversial issues. In order to improve our understanding of the biological meaning of these sper...
Article
Full-text available
Competition between spermatozoa of rival males to gain fertilizations has led to a wide array of modifications in sperm structure and function. Sperm cells of most muroid rodents have hook-shaped extensions in the apical-ventral tip of the head but the function of this structure is largely unknown. These "hooks" may facilitate aggregation of sperma...
Article
Full-text available
Spermcompetition, a prevalent evolutionary process inwhich the spermatozoa of two or more males compete for the fertilization of the same ovum, leads to morphological and physiological adaptations, including increases in energetic metabolism that may serve to propel sperm faster but that may have negative effects onDNA integrity. SpermDNA damage is...
Article
Full-text available
Background: Protamines are sperm nuclear proteins with a crucial role in chromatin condensation. Their function is strongly linked to sperm head morphology and male fertility. Protamines appear to be affected by a complex pattern of selective constraints. Previous studies showed that sexual selection affects protamine coding sequence and expression...
Article
Full-text available
Protamines have a crucial role in male fertility. They are involved in sperm chromatin packaging and influence the shape of the sperm head and, hence, are important for sperm performance. Protamine structure is basic with numerous arginine-rich DNA-binding domains. Postcopulatory sexual selection is thought to play an important role in protamine se...
Article
Full-text available
Mass-specific metabolic rate, the rate at which organisms consume energy per gram of body weight, is negatively associated with body size in metazoans. As a consequence, small species have higher cellular metabolic rates and are able to process resources at a faster rate than large species. Since mass-specific metabolic rate has been shown to const...
Conference Paper
Full-text available
Investment in sperm numbers is a key predictor of success in sperm competition and there is usually a positive relationship between sperm competition level and male reproductive effort on ejaculates, which is often measured using relative testes size (RTS). Demographic processes can drasti- cally alter levels of sperm competition and we should expe...
Article
Full-text available
Although there is ample evidence for the effects of sperm head shape on sperm function, its impact on fertility has not been explored in detail at the intraspecific level in mammals. Here, we assess the relationship between sperm head shape and male fertility in a large-scale study in Manchega sheep (Ovis aries), which have not undergone any select...
Article
Full-text available
Postcopulatory sexual selection, in the form sperm competition, has influenced the evolution of several male reproductive traits. However, theory predicts that sperm competition would lead to tradeoffs between numbers and size of spermatozoa because increased costs per cell would result in a reduction of sperm number if both traits share the same e...
Article
Full-text available
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 tradeoffs between ATP content and sperm motility and velocity. Selecti...
Article
Full-text available
Mouse sperm produce enough ATP to sustain motility by anaerobic glycolysis and respiration. However, previous studies indicated that an active glycolytic pathway is required to achieve normal sperm function, and identified glycolysis as the main source of ATP to fuel the motility of mouse sperm. All the available evidence has been gathered for the...
Article
Full-text available
Sperm competition is a prevalent phenomenon that drives the evolution of sperm function. High levels of sperm competition lead to increased metabolism to fuel higher sperm velocities. This enhanced metabolism can result in oxidative damage (including lipid peroxidation) and damage to the membrane. We hypothesized that in those species experiencing...
Article
Full-text available
PKDREJ is a testis-specific protein thought to be located on the sperm surface. Functional studies in the mouse revealed that loss of PKDREJ has effects on sperm transport and the ability to undergo an induced acrosome reaction. Thus, PKDREJ has been considered a potential target of post-copulatory sexual selection in the form of sperm competition....
Article
Full-text available
Interspecific comparative studies have shown that, in most taxa, postcopulatory sexual selection (PCSS) in the form of sperm competition drives the evolution of longer and faster swimming sperm. Work on passserine birds has revealed that PCSS also reduces variation in sperm size between males at the intraspecific level. However, the influence of PC...
Conference Paper
Full-text available
Sexual selection may promote divergence between populations. Sperm competition, one form of post-copulatory sexual selection, is known to favour changes in ejaculate quality and sperm swimming speed, which improve ejaculate competitiveness. We thus tested the prediction that natural populations from species with high levels of sperm competition sho...
Article
Full-text available
Background Competition between spermatozoa from rival males for success in fertilization (i.e., sperm competition) is an important selective force driving the evolution of male reproductive traits and promoting positive selection in genes related to reproductive function. Positive selection has been identified in reproductive proteins showing rapid...
Article
Full-text available
Abstract Theoretical models have suggested that sperm competition can lead to increased ova resistance to fertilization. While there is some comparative evidence that this might be true, there is no experimental evidence to show that ova defensiveness evolves in response to sperm competition. We performed a series of in vitro fertilization assays t...
Article
Full-text available
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 e...
Article
Full-text available
Proteins involved in sexual reproduction are known to evolve rapidly, often as the result of positive Darwinian selection, although the selective forces driving such adaptive changes are poorly understood. A process of coevolution between proteins in male and female gametes may promote rapid divergence of fertilization proteins. In the mouse, only...
Article
Full-text available
Proteomic studies of spermatozoa have identified a large catalog of integral sperm proteins. Rapid evolution of these proteins may underlie adaptive changes of sperm traits involved in different events leading to fertilization, although the selective forces underlying such rapid evolution are not well understood. A variety of selective forces may d...
Article
Full-text available
Little is known about the genetic basis of evolutionary changes in sperm phenotype. Postcopulatory sexual selection is associated with differences in protamine gene sequences and promoters, and is a powerful force acting on sperm form and function, although links between protamine evolution and sperm phenotype are scarce. Protamines are involved in...
Data
Phylogenetic reconstruction for the 28 marsupial mammal species utilized in the GLS analysis. Phylogenetic position of the higher groups (orders and families) was reconstructed first [54], [55] and group-specific phylogenies were used for Dasyuromorpha and Peramelemorpha [56], and for Diprotodontia [57]–[59]. (EPS)
Article
Full-text available
The sperm membrane is a key structure affecting sperm function and thus reproductive success. Spermatozoa are highly specialized and differentiated cells that undergo a long series of processes in the male and female reproductive tracts until they reach the site of fertilization. During this transit, the sperm membrane is prone to damage such as li...
Article
Full-text available
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 principl...
Article
Full-text available
Sperm competition leads to increased sperm production in many taxa. This response may result from increases in testes size, changes in testicular architecture or changes in the kinetics of spermatogenesis, but the impact of each one of these processes on sperm production has not been studied in an integrated manner. Furthermore, such response may b...