Yazar "Moura A." seçeneğine göre listele

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    Applications of Metabolomics in Reproductive Biology
    (wiley, 2017) Cazaux Velho A.L.; Oliveira R.; Dinh T.; Moura A.; Kaya A.; Memili E.
    Metabolomics can be performed associated with other omics approaches such as genomics, transcriptomics, and proteomics. For example, a recent study showed interesting results using an Integrative Personal Omics Profile (iPOP) to identify markers for possible diseases affecting an individual. This chapter suggests that such a method leads to an early diagnosis and facilitates prevention of certain diseases, such as type 2 diabetes, aplastic anemia, human rhinovirus infection, and respiratory syncytial virus infection. For assisted reproductive technologies (ART), metabolomics methods have been chosen as noninvasive approaches to improve the assessment of embryo quality. Metabolic profiling analysis of follicular fluids (FF) from lactating cows and heifers by gas chromatography-mass spectrometry (GC-MS) identified the presence of greater concentrations of saturated fatty acids in follicles from cows than those from heifers. Large animals have been used as models for research of human disease and physiology due to their specific physiological characteristics, sometimes similar to the human. © 2017 by John Wiley & Sons, Inc. All rights reserved.
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    Sperm Chromatin Dynamics Associated with Male Fertility in Mammals
    (wiley, 2017) Kutchy N.A.; Dogan S.; Kaya A.; Moura A.; Memili E.
    Instead of two protamines (PRM1 and PRM2) as in human and mouse sperms, presence of only PRM1 in bull sperm raises an interesting question about the mechanism(s) regulating sperm chromatin structure. During spermatogenesis, spermatozoa that are present in syncytium share mRNA and proteins through cytoplasmic bridges and are phenotypically diploid. Chromatin remodeling occurs during spermatogenesis where linker histones are gradually replaced by testis-specific variants, followed by the replacement of histones with transition proteins and then with protamines. Increased percentage of histone retention is expected to cause infertility in males. Although protamines are involved in sperm chromatin condensation and function, there is restrictive positive selection on only a few functional sites. Improper packaging of sperm DNA caused partly by reduced protamination predisposes sperm DNA to damage, which then interferes with fertilization and early embryonic development. Abnormal chromatin condensation in sperm during spermatogenesis and abnormal chromatin decondensation during pronucleus formation (postfertilization) can result in reproductive problems. © 2017 by John Wiley & Sons, Inc. All rights reserved.
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    Sperm protamine-status correlates to the fertility of breeding bulls
    (Society for the Study of Reproduction, 2015) Dogan S.; Vargovic P.; Oliveira R.; Belser L.E.; Kaya A.; Moura A.; Sutovsky P.
    During fertilization, spermatozoa make essential contributions to embryo development by providing oocyte activating factors, centrosomal components, and paternal chromosomes. Protamines are essential for proper packaging of sperm DNA; however, in contrast to the studies of oocyte-related female infertility, the influence of sperm chromatin structure on male infertility has not been evaluated extensively. The objective of this study was to determine the sperm chromatin content of bull spermatozoa by evaluating DNA fragmentation, chromatin maturity/protamination, PRM1 protein status, and nuclear shape in spermatozoa from bulls with different fertility. Relationships between protamine 1 (PRM1) and the chromatin integrity were ascertained in spermatozoa from Holstein bulls with varied (high vs. low) but acceptable fertility. Sperm DNA fragmentation and chromatin maturity (protamination) were tested using Halomax assay and toluidine blue staining, respectively. The PRM1 content was assayed using Western blotting and in-gel densitometry, flow cytometry, and immunocytochemistry. Fragmentation of DNA was increased and chromatin maturity significantly reduced in spermatozoa from low-fertility bulls compared to those from high-fertility bulls. Field fertility scores of the bulls were negatively correlated with the percentage of spermatozoa displaying reduced protamination and fragmented DNA using toluidine blue and Halomax, respectively. Bull fertility was also positively correlated with PRM1 content by Western blotting and flow cytometry. However, detection of PRM1 content by Western blotting alone was not predictive of bull fertility. In immunocytochemistry, abnormal spermatozoa showed either a lack of PRM1 or scattered localization in the apical/acrosomal region of the nuclei. The nuclear shape was distorted in spermatozoa from low-fertility bulls. In conclusion, we showed that inadequate amount and localization of PRM1 were associated with defects in sperm chromatin structure, coinciding with reduced fertility in bulls. These findings are highly significant because they reveal molecular and morphological phenotypes of mammalian spermatozoa that influence fertility. © 2015 by the Society for the Study of Reproduction, Inc.