Mayra Elena Ortiz D'Ávila Assumpção (original) (raw)

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Papers by Mayra Elena Ortiz D'Ávila Assumpção

BMC Research Notes, 2011

Background: Ureaplasma diversum has been associated with infertility in cows. In bulls, this moll... more Background: Ureaplasma diversum has been associated with infertility in cows. In bulls, this mollicute colonizes the prepuce and distal portion of the urethra and may infect sperm cells. The aim of this study is to analyze in vitro interaction of U. diversum isolates and ATCC strains with bovine spermatozoids. The interactions were observed by confocal microscopy and the gentamycin internalization assay. Findings: U. diversum were able to adhere to and invade spermatozoids after 30 min of infection. The gentamicin resistance assay confirmed the intracellularity and survival of U. diversum in bovine spermatozoids. Conclusions: The intracellular nature of bovine ureaplasma identifies a new difficulty to control the reproductive of these animals.

... Endereço para correspondência: JOSÉ ANTONIO VISINTIN Departamento de Reprodução Animal Faculd... more ... Endereço para correspondência: JOSÉ ANTONIO VISINTIN Departamento de Reprodução Animal Faculdade de ... Marques de Paiva, 87 Cidade Universitária Armando Salles Oliveira 05508-270 São ... pela coloração com iodeto de propídio e diacetato de carboxifluoresceína e ...

Acta Scientiae Veterinariae, 2011

Background: The establishment of an in vitro production (IVP) of embryo in swine allows the gener... more Background: The establishment of an in vitro production (IVP) of embryo in swine allows the generation of embryos with the same quality as in vivo produced embryos with less costs and time. In order to achieve successful fertilization under normal circumstances in vivo, mammalian spermatozoa must first undergo capacitation and then acrosome reaction. The purpose of this study was compared the efficacious of IP/CFDA fluorescence and Coomassie Blue G (CB) staining to detect capacitated sperm cells in refrigerated and fresh semen. Morever, it was investigated the efficacious of caffeine and chondroitin sulphate to promote in vitro sperm capacitation and in vitro embryo produced (IVP) of swine embryos. Materials, Methods & Results: A sperm-rich fraction from ejaculate was obtained using the gloved-hand method and the gelfree fraction was separated using sterile gauze. The semen was diluted in BTS at a final concentration of 1.5 x 10 8 cells/mL. The sperm suspension was incubated for 2 h at 25°C, refrigerated and maintained for 1 h at 15-18°C (refrigerated group) or used immediately (fresh group). Sperm capacitation was assessed by IP/CFDA fluorescence and CB staining for both fresh and refrigerated semen. For PI/CFDA evaluation, a final solution containing 1.7 mM formaldehyde, 7.3 mM PI and 20 mM CFDA in 950 µL saline was prepared. In the dark, 40 µL PI/CFDA final solution was added to 10 µL semen and after 8 min, slides were analyzed on epifluorescence microscopy. For CB evaluation, sperm cells were fixed in 4% paraformaldehyde for 10 min and centrifuged twice at 320 x g in ammonium acetate pH 9 for 8 min. A smear was made and stained with 2.75 mg/mL CB in solution containing 12.5% methanol, 25% glacial acetic acid and 62.5% water, for 2 min. The smear was washed in running water, air dried and sealed with Permount ® , diluted 2:1 in xilol to avoid staining oxidation. Our results showed that refrigeration did not affect sperm capacitation and comparing staining methods, the PI/CFDA combination was more efficient to detect capacitated sperm, when compared to CB staining. In experiment 2, we evaluated the effect of different incubation time (1-5 h) with chondroitin sulfate and caffeine on sperm capacitation. For in vitro fertilization, oocytes were obtained from slaughterhouse ovaries. Oocytes with a thick and intact cumulus oophurus layer and cytoplasm with homogenous granules were selected for in vitro maturation for 44 h. According to the results of experiment 2, it was used for in vitro fertilization refrigerated semen was capacitated with 50 µg/mL chondroitin sulfate for 2 h or capacitated with 5 µg/mL caffeine for 3 h. Six hours after insemination, cumulus oophorus cells were mechanically removed and oocytes were washed and incubated in microdrops of culture medium. Embryo development after fertilization with sperm capacitated with caffeine or chondroitin sulfate was evaluated on days 3, 5 and 7 of culture. No differences were observed in days 3 or 5 of in vitro culture. However, it was observed an increase on blastocyst rate on Day 7 of culture when caffeine was used as the capacitor agent. Discussion: Molecular basis of sperm capacitation is still poor understood. Sperm capacitation can occur in vitro spontaneously in defined media without addition of biological fluids. We observed that sperm capacitation increased as incubation period enlarged and it was observed using Coomassie blue G and PI/CFDA for fresh semen and for refrigerated semen. It can be concluded that the cooling of semen did not change their pattern of sperm capacitation and this is best assessed by IP/CFDA than by CB. In addition to the use of caffeine in sperm capacitation produces more blastocysts than the chondroitin sulfate after in vitro fertilization.

Animal reproduction, 2012

Reproduction in Domestic Animals, Aug 1, 2012

Molecular Reproduction and Development, Sep 1, 2011

Brazilian Journal of Veterinary Research and Animal Science, 2000

I-Departamento deReproduyao Animal daFaculdade deMedicina Veterinciria e Zootecnia daUSP-SP Compa... more I-Departamento deReproduyao Animal daFaculdade deMedicina Veterinciria e Zootecnia daUSP-SP Compacted mouse morulae were frozen at 0.3°C/min ute or O.SOC/minute from-6°C to-24°C or-32°C in 10% of glycero l plus differe nt sucrose co ncentratio ns with or witho ut 0. 1% of honeybee roya l jelly, Embryos were thawed in water bath at 22°C for 20 seconds and cryoprotectant dilution was done in three steps, Embryos were cultured in Whitte n's medium for 24, 48 and 72 hours at 37°C, 5% of CO 2 and 100% of humidity. The i ll vitro deve lopme nt ranged from 56,6% to 100% after 72 hours, Expanded blastocysts were transferred to pseudopregnant recipients on the third day of the estrou s cycle. Viable fetuses rates for embryos frozen to-24 or-32°C at 0.3°C/min ute in 10% glycerol + 10% sucrose, 10% glycerol + 10% sucrose + 0, I% honeybee roya l je lly, 10% glycero l + 0,1% honeybee roya l jelly or 10% glycerol were respectively: 28,1 % and 13.6%, 48.7% and 31.9 %, 28,6 % and 13.2%, 20.0% and 42.4 %. Viable fetuses for embryos frozen to-24°C or-32°C at OSC/minute in 10% glycero l + 10% sucrose or 10% glycerol + 10% sucrose + 0.1% honeybee royal jelly were respective ly 29.0% and 15.3%,48.8% and 32.0%. We can conclude that addition of 10% sucrose to 10% glycerol was effic ient for embryo freezing at 0.3 or OSC/m inute and plunged in liquid nitrogen at-24°C. The honeyb ee royal jell y addition provided higher viable fetu ses rates when embryos were coo led at 0.3 or OSC/minute and plunged in liquid nitrogen at-24°C. .

Acta Scientiae Veterinariae, 2006

Reproduction, Fertility and Development, 2006

Brazilian Journal of Veterinary Research and Animal Science, Jun 1, 2006

Zygote, Aug 19, 2019

Summary Long-term heat stress (HS) induced by testicular insulation generates oxidative stress (O... more Summary Long-term heat stress (HS) induced by testicular insulation generates oxidative stress (OS) on the testicular environment; consequently activating antioxidant enzymes such as superoxide dismutase (SOD), glutathione reductase (GR) and glutathione peroxidase (GPx). The aim of this work was to immunolocalize antioxidant enzymes present in different cells within the seminiferous tubule when rams were submitted to HS. Rams were divided into control (n = 6) and treated group (n = 6), comprising rams subjected to testicular insulation for 240 h. After the testicular insulation period, rams were subjected to orchiectomy. Testicular fragments were submitted to immunohistochemistry for staining against SOD, GR and GPx enzymes. We observed immunolocalization of GPx in more cell types of the testis after HS and when compared with other enzymes. In conclusion, GPx is the main antioxidant enzyme identified in testicular cells in an attempt to maintain oxidative balance when HS occurs.

Arquivos da Faculdade de Veterinaria da Ufrgs, 1996

Reproduction in Domestic Animals, 2021

This study aimed to evaluate the effect of seminal plasma on bovine sperm cryopreservation and to... more This study aimed to evaluate the effect of seminal plasma on bovine sperm cryopreservation and to assess the integrity of plasma and acrosomal membranes, mitochondrial potential, remodelling of F‐actin cytoskeleton and sperm chromatin fragmentation during the cooling, equilibrium and freezing/thawing stages. Six ejaculates collected from seven Nelore bulls (n = 42) were used in this study. Each ejaculate was divided into two aliquots (with seminal plasma = SP group; without seminal plasma = NSP group) and packed to a final concentration of 50 × 106 sperm per straw. Statistical analyses were performed using SAS software (version 9.3), and p ≤ .05 was considered significant. A time effect was observed for all sperm characteristics (p < .05), except for chromatin fragmentation (p > .05). The presence of seminal plasma better preserved the acrosomal integrity (SP = 75.2% and NSP = 71.7%; p < .05) and also provided lower F‐actin remodelling during cryopreservation process (SP = ...

Biology of Reproduction, 2007