Publications by authors named "Olga Garcia-Alvarez"

There are currently no vaccines available to prevent and control of Anaplasma phagocytophilum, an intracellular bacterial pathogen transmitted by ticks that occurs in many regions of the world and causes disease in a wide range of domestic and wild hosts, including humans. Vaccines induce long-lasting immunity and could prevent or reduce transmission of this pathogen. Understanding how vaccines induce a protective response can be difficult due to the complexity of the immune system, which operates at many levels throughout the organism.

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Major surface protein 4 (MSP4) plays a role during infection and multiplication in host neutrophils and tick vector cells. Recently, vaccination trials with the antigen MSP4 in sheep showed only partial protection against pathogen infection. However, in rabbits immunized with MSP4, this recombinant antigen was protective.

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Deficient sperm motility is a frequent cause of the age-related male sub-/infertility. Since the protein sirtuin 1 (SIRT1) develops anti-aging action and participates in sperm motility and ATP synthesis in mitochondria, we investigated its role in the acquisition of hyperactivated motility during capacitation. For this, the dynamics of sperm subpopulations were studied, using males of Sirt1 heterozygous mutant mice.

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Incubation with estrous sheep serum (ESS) is required to induce in vitro capacitation of spermatozoa during in vitro fertilization of small ruminants. However, the effect of adding different serum concentrations in the fertilization media on the quality of resulting blastocysts has not yet been studied. Here, 298 sheep oocytes were co-incubated with capacitated spermatozoa with either 10% or 2% ESS.

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Creating germplasm banks of wild species, such as the Iberian red Deer () can be challenging. One of the main difficulties is the obtention and cryopreservation of good-quality reproductive cells when the spermatozoa are obtained from epididymides after death. To avoid a loss of seminal quality during transport, developing alternative methods for cooling and freezing sperm samples under field conditions is necessary.

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Oxidative stress has become a major concern in the field of spermatology, and one of the possible solutions to this acute problem would be the use of antioxidant protection; however, more studies are required in this field, as highly contradictory results regarding the addition of antioxidants have been obtained. Vitamin E is a powerful biological antioxidant, but its low stability and high hydrophobicity limit its application in spermatology, making the use of organic solvents necessary, which renders spermatozoa practically motionless. Keeping this in mind, we propose the use of hydrogels (HVEs) and nanoemulsions (NVEs), alone or in combination, as carriers for the controlled release of vitamin E, thus, improving its solubility and stability and preventing oxidative stress in sperm cells.

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The heterogeneous nature of ejaculates highlights the relevance of studying the behavior of different sperm subpopulations. Changes in sperm motility and the increase in tyrosine phosphorylation are key events that usually occur during capacitation and can be modified by the cryopreservation process. However, the relationship between both events remains poorly defined throughout capacitation in the different sperm subpopulations.

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Article Synopsis
  • * Results indicated that melatonin significantly increased calf weights and advanced calving dates while enhancing fertility rates by 46% for the yearling hinds treated with melatonin, even when they had lower initial weights.
  • * Maintaining treated and non-treated groups separately showed better fertility rates for melatonin-treated hinds, but when mixed together, their fertility rates equalized, suggesting management strategies for improving farm productivity with melatonin use.
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Background: Bisphenol S (BPS) is increasingly used as a replacement for bisphenol A in the manufacture of products containing polycarbonates and epoxy resins. However, further studies of BPS exposure are needed for the assessment of health risks to humans. In this study we assessed the potential harmfulness of low-dose BPS on reproduction in male mice.

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Sperm cryopreservation represents a powerful tool for livestock breeding. Several efforts have been made to improve the efficiency of sperm cryopreservation in different ruminant species. However, a significant amount of sperm still suffers considerable cryodamage, which may affect sperm quality and fertility.

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Sperm cryopreservation is a complex process that needs to be adapted to wild and domestic avian species to ensure proper efficiency. Because of its accessibility, the peregrine falcon may be used as a good model for studying other raptor species. To find the most optimal cryopreservation protocol for peregrine falcon ejaculates, sperm parameters such as motility, viability, DNA fragmentation, acrosome integrity, and mitochondrial activity were analyzed under different conditions by varying the freezing method (slow freezing in straws vs.

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Article Synopsis
  • The study investigates the controversial role of fetal calf serum (FCS) in in vitro embryo culture for red deer, aiming to determine its necessity and optimal timing for supplementation.
  • Although the use of FCS did not influence the overall cleavage and blastocyst rates, it significantly improved the cell count in blastocysts when added at 48 hours post-insemination.
  • The findings suggest that while FCS does not affect embryo yield, it enhances the quality of red deer blastocysts when introduced at the right time.
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Chromatin remodeling, including histone post-translational modifications, during spermatogenesis can affect sperm quality and fertility, and epigenetic marks may therefore be useful for clinical evaluations of sperm. Together with histone hyperacetylation, the dimethylation of histone H3 on lysine K4 (H3K4me2) is also required during protamination. Accordingly, we evaluated the utilization of this epigenetic mark for the identification of sperm with decrease quality and immature chromatin.

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The aim of this study was to assess the effect of insemination timing on pregnancy rates in red deer (Cervus elaphus) when using sex-sorted sperm samples. Semen was collected by electroejaculation from 8 mature stags and processed to obtain: Conventional samples, following standard freezing procedures for commercial purposes; Control sorted samples, diluted and handled as per sorted samples but without being submitted to the sorter passage; and Y Sex Sorted (YSS) samples. Hinds were synchronized via intravaginal CIDR (Controlled Internal Drug Release) placement and given eCG (Folligon PMSG Serum Gonadotrophin) on day 12, upon CIDR removal.

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Since sperm size and form do not necessarily provide information on internal sperm structures, novel sperm markers need to be found in order to conduct assisted reproductive therapies (ART) successfully. Currently, the priority of andrologists is not only to select those sperm able to fertilize the oocyte, but also a high quality of sperm that will guarantee a healthy embryo. Evidence of this shows us the importance of studying sperm intensively on genetic and epigenetic levels, because these could probably be the cause of a percentage of infertility diagnosed as idiopathic.

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The aim of this study was to determine the effect of Camellia sinensis extract as antioxidant supplement and pre-freezing equilibration times in a soybean lecithin extender for freezing ram semen. In this study, a total of 20 ejaculates were collected from four Ghezel rams and diluted with extenders (1.5% soybean lecithin, 7% glycerol) containing no supplements (control) and Camellia sinensis extract (5, 10, and 15 mg/L) and cryopreserved, immediately after thermal equilibrium was reached at 5 °C (0 h), or 4 h after equilibration.

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Currently, sperm reproductive biotechnologies such as sex sorting and cryopreservation are undoubtedly valuable tools for improving the economic and biological efficiency of red deer production systems. In this context, and because of the particular characteristics of this species (extensive exploitation typically far from laboratory facilities), a key goal is to optimize the design of an adequate handling protocol of sperm samples before samples are subjected to sex sorting and cryopreservation procedures to obtain better outputs from the application of these technologies. The main aim of this paper was to design an adequate protocol for Iberian red deer sperm handling before sex sorting by flow cytometry to obtain optimal yields when sex sorting is used in this species.

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The spermatozoon is the most diverse cell type known and this diversity is considered to reflect differences in sperm function. How the diversity in sperm morphology arose during speciation and what role the different specializations play in sperm function, however, remain incompletely characterized. This work reviews the hypotheses proposed to explain sperm morphological evolution, with a focus on some aspects of sperm morphometric evaluation; the ability of morphometrics to predict sperm cryoresistance and male fertility is also discussed.

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Sperm competition, a prevalent evolutionary process in which 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 on DNA integrity. Sperm DNA damage is associated with reduced rates of fertilization, embryo and fetal loss, offspring mortality, and mutations leading to genetic disease. We tested whether high levels of sperm competition affect sperm DNA integrity.

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The present study aimed to examine the behavior of ram spermatozoa subjected to a vitrification process in free-egg yolk diluents in relation with conventional diluents and cryopreservation protocol used in this species. Previously it was investigated the toxicity of cryoprotectants, sucrose and glycerol, based on different concentrations (sucrose at 0.03 M, 0.

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Heat shock (HS) is one of the best-studied exogenous cellular stresses. Almost all tissues, cell types, metabolic pathways and biochemical reactions are affected in greater or lesser extent by HS. However, there are some especially thermo sensible cellular types such as the mammalian male germ cells.

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The aim of the present study was to evaluate the effect of sperm reactive oxygen species (ROS) production and DNA changes on male fertility. For that purpose, six rams with significantly different pregnancy rates were used; these were classified as having high fertility, i.e.

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The present study addresses the effect of heat stress on males' reproduction ability. For that, we have evaluated the sperm DNA fragmentation (DFI) by SCSA of ejaculates incubated at 37 °C during 0, 24 and 48 hours after its collection, as a way to mimic the temperature circumstances to which spermatozoa will be subject to in the ewe uterus. The effects of temperature and temperature-humidity index (THI) from day 60 prior collection to the date of semen collection on DFI were examined.

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Sperm design and velocity play key roles in influencing sperm performance and, therefore, can determine fertilization success. Several interspecific studies have demonstrated how these features correlate, and it has been hypothesized that selection may drive changes in these sperm traits. Here, we examine the association between sperm design and swimming velocity in a study conducted at an intraspecific level in Iberian red deer (Cervus elaphus hispanicus).

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The collection of sperm samples by electroejaculation (EE) leads to an increase of the production of seminal plasma which could modify the tolerance of spermatozoa to the cryopreservation procedure. This study aims to compare a standard sperm cryopreservation protocol for samples collected by artificial vagina (AV) with the same protocol and modifications to this for samples obtained by EE. Semen from six males of Blanca-Celtibérica goat breed was collected by AV (control) and EE, and three experiments were conducted.

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