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137 result(s) for "Oocytes - virology"
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High-security closed devices are efficient and safe to protect human oocytes from potential risk of viral contamination during vitrification and storage especially in the COVID-19 pandemic
PurposeThe main purpose and research question of the study are to compare the efficacy of high-security closed versus open devices for human oocytes’ vitrification.MethodsA prospective randomized study was conducted. A total of 737 patients attending the Infertility and IVF Unit at S.Orsola University Hospital (Italy) between October 2015 and April 2020 were randomly assigned to two groups. A total of 368 patients were assigned to group 1 (High-Security Vitrification™ - HSV) and 369 to group 2 (Cryotop® open system). Oocyte survival, fertilization, cleavage, pregnancy, implantation, and miscarriage rate were compared between the two groups.ResultsNo statistically significant differences were observed on survival rate (70.3% vs. 73.3%), fertilization rate (70.8% vs. 74.9%), cleavage rate (90.6% vs. 90.3%), pregnancy/transfer ratio (32.0% vs. 31.8%), implantation rate (19.7% vs. 19.9%), nor miscarriage rates (22.1% vs. 21.5%) between the two groups. Women’s mean age in group 1 (36.18 ± 3.92) and group 2 (35.88 ± 3.88) was not significantly different (P = .297). A total of 4029 oocytes were vitrified (1980 and 2049 in groups 1 and 2 respectively). A total of 2564 were warmed (1469 and 1095 in groups 1 and 2 respectively). A total of 1386 morphologically eligible oocytes were inseminated by intracytoplasmic sperm injection (792 and 594 respectively, P = .304).ConclusionsThe present study shows that the replacement of the open vitrification system by a closed one has no impact on in vitro and in vivo survival, development, pregnancy and implantation rate. Furthermore, to ensure safety, especially during the current COVID-19 pandemic, the use of the closed device eliminates the potential samples’ contamination during vitrification and storage.
Transcriptomic responses of cumulus granulosa cells to SARS-CoV-2 infection during controlled ovarian stimulation
Cumulus granulosa cells (CGCs) play a crucial role in follicular development, but so far, no research has explored the impact of SARS-CoV-2 infection on ovarian function from the perspective of CGCs. In the present study, we compared the cycle outcomes between infected and uninfected female patients undergoing controlled ovarian stimulation, performed bulk RNA-sequencing of collected CGCs, and used bioinformatic methods to explore transcriptomic changes. The results showed that women with SARS-CoV-2 infection during stimulation had significantly lower number of oocytes retrieved and follicle-oocyte index, while subsequent fertilization and embryo development were similar. CGCs were not directly infected by SARS-CoV-2, but exhibited dramatic differences in gene expression (156 up-regulated and 65 down-regulated). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses demonstrated a high enrichment in antiviral, immune and inflammatory responses with necroptosis. In addition, the pathways related to telomere organization and double strand break repair were significantly affected by infection in gene set enrichment analysis. Further weighted gene co-expression network analysis identified a key module associated with ovarian response traits, which was mainly enriched as a decrease of leukocyte chemotaxis and migration in CGCs. For the first time, our study describes how SARS-CoV-2 infection indirectly affects CGCs at the transcriptional level, which may impair oocyte-CGC crosstalk and consequently lead to poor ovarian response during fertility treatment.
Bovine herpesvirus 1 can cross the intact zona pellucida of bovine oocytes after artificial infection
Bovine herpesvirus 1 (BHV1) is an important bovine pathogen, responsible for respiratory diseases and reproductive problems. This study investigated the penetration capacity of BHV1 into oocytes after co-incubation for either 1 h or 24 h. Immunofluorescence assays in cumulus-oocyte complexes (COCs) and denuded oocytes (without the presence of cumulus cells) were performed and evaluated using confocal laser scanning microscopy. Blood samples and ovaries from BHV1 seronegative cows were used. The oocytes recovered were divided into two groups. Group I comprised COCs (n = 312) and denuded oocytes (n = 296), which were experimentally infected with BHV1 and incubated for 1 h at 38.5°C and 5% CO2. Group II comprised COCs (n = 425) and denuded oocytes (n = 405), which were co-incubated with BHV1 under the same conditions for 24 h. The negative control of these two groups was respectively subjected to the same protocol, except for exposure to BHV1. To our knowledge, this study provides the first evidence of BHV1 detection within COCs and denuded oocytes exhibiting intact zona pellucida when co-incubated with the virus for 24 h. Immunolocalization also confirmed the presence of BHV1 in the cytoplasm of the cumulus cells of all COCs exposed to the virus after both incubation periods. In conclusion, detection of BHV1 inside oocytes has a great meaning for the field of animal reproduction. The detection of BHV1 in different layers of cumulus cells also demonstrates that these cells are sources of viral infection.
The citrus tristeza virus p33 protein functions as a viroporin
Viroporins are viral proteins that form ion channels in the membranes of the host and, thus, alter the host ion homeostasis to create more favorable environments for the virus. Since the discovery of the ion channel activity of the M2 protein encoded by influenza virus A (species: Alphainfluenzavirus influenzae ), many additional viral proteins have also been characterized as viroporins. However, most viroporins known thus far belong to animal viruses, while the discovery of plant virus viroporins has significantly lagged. In this work, we present evidence that the p33 protein, a membrane-associated protein of citrus tristeza virus (CTV; species: Closterovirus tristezae ), possesses the characteristics of a viroporin. We first show the substantial structural similarities between the transmembrane and cytoplasmic domains of known Class I viroporins and those of the p33 protein. Using two-voltage electrode clamp assays in Xenopus oocytes, we further demonstrate the ion channel properties of p33 such as the ability to induce strong inward currents of potassium and sodium when activated at lowered membrane potentials. Finally, using confocal and electron microscopy, we show that, similarly to other Class I viroporins, the p33 protein triggers extensive membrane remodeling and discuss additional characteristics of p33 and the functions of this protein in the CTV infection, which resemble those found with viroporins of other viruses. This study represents the third report of a viroporin encoded by a plant virus and the first validation of the ability of a plant virus viroporin to induce currents across eukaryotic membranes using electrophysiological assays. The findings of this work open new avenues in research focusing on the understanding the role of viroporins in plant virus infections.
The SARS-CoV-2 ORF6 protein inhibits nuclear export of mRNA and spliceosomal U snRNA
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 19 (COVID-19). SARS-CoV-2 infection suppresses host innate immunity and impairs cell viability. Among the viral proteins, ORF6 exhibits potent interferon (IFN) antagonistic activity and cellular toxicity. It also interacts with the RNA export factor RAE1, which bridges the nuclear pore complex and nuclear export receptors, suggesting an effect on RNA export. Using the Xenopus oocyte microinjection system, I found that ORF6 blocked the export of not only mRNA but also spliceosomal U snRNA. I further demonstrated that ORF6 affects the interaction between RAE1 and nuclear export receptors and inhibits the RNA binding of RAE1. These effects of ORF6 may cumulatively block the export of several classes of RNA. I also found that ORF6 binds RNA and forms oligomers. These findings provide insights into the suppression of innate immune responses and the reduction in cell viability caused by SARS-CoV-2 infection, contributing to the development of antiviral drugs targeting ORF6.
Risk of Contamination of Gametes and Embryos during Cryopreservation and Measures to Prevent Cross-Contamination
The introduction and widespread application of vitrification are one of the most important achievements in human assisted reproduction techniques (ART) of the past decade despite controversy and unclarified issues, mostly related to concerns about disease transmission. Guidance documents published by US Food and Drug Administration, which focused on the safety of tissue/organ donations during Zika virus spread in 2016, as well as some reports of virus, bacteria, and fungi survival to cryogenic temperatures, highlighted the need for a review of the way how potentially infectious material is handled and stored in ART-related procedures. It was experimentally demonstrated that cross-contamination between liquid nitrogen (LN2) and embryos may occur when infectious agents are present in LN2 and oocytes/embryos are not protected by a hermetically sealed device. Thus, this review summarizes pertinent data and opinions regarding the potential hazard of infectious transmission through cryopreserved and banked reproductive cells and tissues in LN2. Special attention is given to the survival of pathogens in LN2, the risk of cross-contamination, vitrification methods, sterility of LN2, and the risks associated with the use of straws, cryovials, and storage dewars.
The Effect of Bovine Viral Diarrhoea Virus Biotypes on Bovine Oocyte In Vitro
Bovine viral diarrhoea virus (BVDV) is a significant pathogen in the global cattle population, with two biotypes: cytopathic (CP) and non‐cytopathic (NCP), differing in their effects on cell culture. This study aimed to examine the impact of BVDV on the expression of apoptosis‐related genes and total antioxidant capacity (TAC) in vitro. Oocytes were obtained from post‐slaughter bovine ovaries and infected with both BVDV biotypes in vitro. Gene expression levels of bcl 2, bax, caspase 3 and caspase 9 were assessed using reverse transcription‐quantitative PCR (RT‐qPCR). The results indicated significant differences in gene expression levels, with bcl 2 expression reduced in CP and NCP‐infected oocytes compared to the control group (p < 0.05). Additionally, bax and caspase 3 expression levels were significantly elevated in the CP BVDV groups (p < 0.05). In the NCP BVDV groups, the expression of bcl 2 decreased (p < 0.05), while caspase 9 expression increased by 3.588‐fold compared to the control group (p < 0.05). Furthermore, TAC levels in the CP groups were significantly lower than those in the control group (p < 0.05). These findings suggest that the CP biotype of BVDV markedly affects TAC and alters the expression of key apoptosis‐related genes, while the NCP biotype reduces bcl 2 expression and increases caspase 9 expression. Bovine viral diarrhoea virus (BVDV) is a significant pathogen with two biotypes, cytopathic (CP) and non‐cytopathic (NCP). The aims were to examine the impact of BVDV on the expression of genes related to apoptosis and total antioxidant capacity (TAC) in vitro. Oocytes were infected with two BVDV biotypes. For assessing the bcl 2, bax, caspase 3 and caspase 9 gene expression, RT‐qPCR was used. The results showed significant differences in gene expression levels, including bcl 2, bax, caspase 3 and caspase 9, in the CP BVDV groups compared to the control group. Only bcl 2 and caspase 9 expression levels significantly decreased in the NCP BVDV groups compared to the control group. In addition, the CP groups TAC levels were much lower than those of the control group. It can be inferred that CP BVDV has a notable impact on the TAC of oocytes and alters the expression of genes such as bcl 2, bax, caspase 3 and caspase 9. However, the NCP biotype only leads to a decrease in expression of bcl 2 and caspase 9.
Molecular Characterization of the First Bovine Herpesvirus 4 (BoHV-4) Strains Isolated from In Vitro Bovine Embryos production in Argentina
Bovine herpesvirus 4 (BoHV-4) is increasingly considered as responsible for various problems of the reproductive tract. The virus infects mainly blood mononuclear cells and displays specific tropism for vascular endothelia, reproductive and fetal tissues. Epidemiological studies suggest its impact on reproductive performance, and its presence in various sites in the reproductive tract highlights its potential transmission in transfer-stage embryos. This work describes the biological and genetic characterization of BoHV-4 strains isolated from an in vitro bovine embryo production system. BoHV-4 strains were isolated in 2011 and 2013 from granulosa cells and bovine oocytes from ovary batches collected at a local abattoir, used as \"starting material\" for in vitro production of bovine embryos. Compatible BoHV-4-CPE was observed in the co-culture of granulosa cells and oocytes with MDBK cells. The identity of the isolates was confirmed by PCR assays targeting three ORFs of the viral genome. The phylogenetic analyses of the strains suggest that they were evolutionary unlinked. Therefore it is possible that BoHV-4 ovary infections occurred regularly along the evolution of the virus, at least in Argentina, which can have implications in the systems of in vitro embryo production. Thus, although BoHV-4 does not appear to be a frequent risk factor for in vitro embryo production, data are still limited. This study reveals the potential of BoHV-4 transmission via embryo transfer. Moreover, the high variability among the BoHV-4 strains isolated from aborted cows in Argentina highlights the importance of further research on the role of this virus as an agent with the potential to cause reproductive disease in cattle. The genetic characterization of the isolated strains provides data to better understand the pathogenesis of BoHV-4 infections. Furthermore, it will lead to fundamental insights into the molecular aspects of the virus and the means by which these strains circulate in the herds.
Human Oocytes Express Both ACE2 and BSG Genes and Corresponding Proteins: Is SARS-CoV-2 Infection Possible?
In addition to a number of scientific and medical questions about SARS-CoV-2 infection that still need to be answered, there is also the question of how this highly virulent virus and COVID-19 disease affect gametogenesis in humans. Even more important is the question of whether the virus can also enter and infect oocytes and possibly alter them in an unknown way, which could also affect the development and status of the human embryo. The answers to these questions are still poorly known, so we reviewed the human oocyte transcriptome and proteome obtained in our previous studies and found that human oocytes from the in vitro fertilization program expressed both the ACE2 and BSG genes and the corresponding ACE2 and BSG proteins. This means that human oocytes possess the molecular ‘machinery’ to facilitate SARS-CoV-2 entrance and infection. According to various studies, especially in animal models, different viruses can infect oocytes, so infection of the oocyte with SARS-Cov-2 cannot be completely ruled out. A hypothetical model of human oocyte infection with this virus has been proposed.
Viral highway to nucleus exposed by image correlation analyses
Parvoviral genome translocation from the plasma membrane into the nucleus is a coordinated multistep process mediated by capsid proteins. We used fast confocal microscopy line scan imaging combined with image correlation methods including auto-, pair- and cross-correlation, and number and brightness analysis, to study the parvovirus entry pathway at the single-particle level in living cells. Our results show that the endosome - associated movement of virus particles fluctuates from fast to slow. Fast transit of single cytoplasmic capsids to the nuclear envelope is followed by slow movement of capsids and fast diffusion of capsid fragments in the nucleoplasm. The unique combination of image analyses allowed us to follow the fate of intracellular single virus particles and their interactions with importin β revealing previously unknown dynamics of the entry pathway.