Time filter

Source Type


Marcos-Carcavilla A.,INIA | Mutikainen M.,Mtt Agrifood Research Finland | Gonzalez C.,INIA | Kantanen J.,Mtt Agrifood Research Finland | And 3 more authors.
Cell Stress and Chaperones | Year: 2010

Molecular chaperones have long been understood to be preferentially transcribed in response to multiple perturbations of the cellular homeostasis. In this study, several polymorphisms in the gene encoding the inducible form of the cytoplasmic Hsp90 (HSP90AA1) were addressed in 24 sheep breeds reared in different climatic regions of Europe, Africa, and Asia. Significant differences in the genotype frequencies for a C/G single nucleotide polymorphism (SNP) located at position-660 in the HSP90AA1 5'flanking region were found between the different breeds. Regression analyses reflected significant correlations (from 0.41 to 0.62) between the alternative genotypes of this polymorphism and several climatic and geographic variables characteristic of the regions where these breeds are reared. Real-time analysis revealed that animals bearing the CC -660 genotype presented higher expression levels than those presenting the CG-660 or GG-660 in summer, but not in spring. Mutation at -660 site seems to affect HSP90AA1 transcription rates which could have important effects on the adaptation to different environmental conditions in sheep. Thus, the variability found in the genotype frequencies for the SNP at -660 in the ovine HSP90AA1 locus could be the result of the different environmental pressures occurring in the regions where these breed are maintained. © Cell Stress Society International 2009.

Ramon M.,National Wildlife Research Institute IREC UCLM CSIC JCCM | Legarra A.,French National Institute for Agricultural Research | Ugarte E.,Basque Institute of Agricultural Research and Development | Garde J.J.,National Wildlife Research Institute IREC UCLM CSIC JCCM | Perez-Guzman M.D.,CERSYRA
Journal of Dairy Science | Year: 2010

The objective of this study was to estimate economic weights of major components of milk (fat and protein) for the Manchega dairy sheep breed. An economic study was carried out and the profit associated with fat and protein yields of milk was calculated as the difference between incomes and costs. Incomes were obtained from milk sales to cheese industry and a reference marked price was used. Costs were calculated considering the energy necessary to produce each of the components of milk, and the price per milk forage unit was calculated as the total expense in feedstuff divided by the total (theoretical) needs of the flock. Economic values were defined as partial derivatives of the profit function with respect to each trait. Economic weights for fat and protein yields were similar, being slightly greater for protein in all cases. For carrier, economic weights were close to zero and negative because an increase in carrier production without changes in fat and protein composition leads to an increase in energy demands, holding the sale price of milk constant. When genetic standard deviations were taken into account and standardized economic values were calculated, an increase in economic value of protein and a decrease in economic value of fat yields were observed. The consequences that different changes in production system conditions have on the estimated economic weights were also studied. In general, economic weights were relatively insensitive to changes in production levels and market prices except for changes on milk price. Given the economic importance shown for fat and protein, milk components should be taken into consideration when breeding objectives for dairy sheep are established. © 2010 American Dairy Science Association.

Ramon M.,CERSYRA | Salces-Ortiz J.,INIA | Gonzalez C.,INIA | Perez-Guzman M.D.,CERSYRA | And 4 more authors.
PLoS ONE | Year: 2014

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. To better understand the causes determining the sensitivity of spermatozoa to heat, this study was conducted in 60 males with alternative genotypes for the SNP G/C-660 of the HSP90AA1 promoter, which encode for the Hsp90α protein. The Hsp90α protein predominates in the brain and testis, and its role in spermatogenesis has been described in several species. Ridge regression analyses showed that days 29 to 35 and 7 to 14 before sperm collection (bsc) were the most critical regarding the effect of heat stress over DFI values. Mixed model analyses revealed that DFI increases over a threshold of 30°C for maximum temperature and 22 for THI at days 29 to 35 and 7 to 14 bsc only in animals carrying the GG-660 genotype. The period 29-35 bsc coincide with the meiosis I process for which the effect of the Hsp90α has been described in mice. The period 7-14 bsc may correspond with later stages of the meiosis II and early stages of epididymal maturation in which the replacement of histones by protamines occurs. Because of GG-660 genotype has been associated to lower levels of HSP90AA1 expression, suboptimal amounts of HSP90AA1 mRNA in GG-660 animals under heat stress conditions make spermatozoa DNA more susceptible to be fragmented. Thus, selecting against the GG-660 genotype could decrease the DNA fragmentation and spermatozoa thermal susceptibility in the heat season, and its putative subsequent fertility gains. © 2014 Ramón et al.

Salces-Ortiz J.,INIA | Ramon M.,CERSYRA | Gonzalez C.,INIA | Dolores Perez-Guzman M.,CERSYRA | And 4 more authors.
PLoS ONE | Year: 2015

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 germcells. The present study examined the role of three INDELs in conjunction with the -660G/C polymorphism located at the HSP90AA1 promoter region over the gene expression rate under HS. Specially, the -668insC INDEL, which is very close to the -660G/C transversion, is a good candidate to be implied in the transcriptional regulation of the gene by itself or in a cooperative way with this SNP. Animals carrying the genotype II-668 showed higher transcription rates than those with ID-668 (FC = 3.07) and DD-668 (FC = 3.40) genotypes for samples collected under HS. A linkage between gene expression and sperm DNA fragmentation was also found. When HS conditions were present along or in some stages of the spermatogenesis, alternative genotypes of the -668insC and -660G/C mutations are involved in the effect of HS over sperm DNA fragmentation. Thus, unfavorable genotypes in terms of gene expression induction (ID-668GC-660 and DD-668GG-660) do not produce enough mRNA (stored asmessenger ribonucleoprotein particles) and Hsp90α protein to cope with future thermal stress which might occur in posterior stages when transcriptional activity is reduced and cell types and molecular processes are more sensible to heat (spermatocytes in pachytene and spermatids protamination). This would result in the impairment of DNA packaging and the consequent commitment of the events occurring shortly after fertilization and during embryonic development. In the short-term, the assessment of the relationship between sperm DNA fragmentation sensitivity and ram's fertility will be of interest to a better understanding of the mechanisms of response to HS and its consequences on animal production and reproduction performance. © 2015 Salces-Ortiz et al.

Ramon M.,CERSYRA | Perez-Guzman M.D.,CERSYRA | Jimenez-Rabadan P.,CERSYRA | Garcia-Alvarez O.,Campus Universitario Sn | And 5 more authors.
PLoS ONE | Year: 2013

Background: Sperm cryopreservation has become an indispensable tool in biology. Initially, studies were aimed towards the development of efficient freezing protocols in different species that would allow for an efficient storage of semen samples for long periods of time, ensuring its viability. Nowadays, it is widely known that an important individual component exists in the cryoresistance of semen, and efforts are aimed at identifying those sperm characteristics that may allow us to predict this cryoresistance. This knowledge would lead, ultimately, to the design of optimized freezing protocols for the sperm characteristics of each male. Methodology/Principal Findings: We have evaluated the changes that occur in the sperm head dimensions throughout the cryopreservation process. We have found three different patterns of response, each of one related to a different sperm quality at thawing. We have been able to characterize males based on these patterns. For each male, its pattern remained constant among different ejaculates. This latter would imply that males always respond in the same way to freezing, giving even more importance to this sperm feature. Conclusions/Significance: Changes in the sperm head during cryopreservation process have resulted useful to identify the ability of semen of males for freezing. We suggest that analyses of these response patterns would represent an important tool to characterize the cryoresistance of males when implemented within breeding programs. We also propose follow-up experiments to examine the outcomes of the use of different freezing protocols depending on the pattern of response of males. © 2013 Ramón et al.

Discover hidden collaborations