نتایج جستجو برای: spermiogenesis

تعداد نتایج: 1070  

Journal: :Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms 2014

2015
Michael Mitchell

The nuclear lamina takes centre stage during spermiogenesis, the post-meiotic phase of spermatogenesis, when haploid round spermatids differentiate into spermatozoa: the acrosome and flagellum develop at opposite nuclear poles, the nucleus elongates and, as the nuclear histones are replaced with protamines, the chromatin condenses, to produce the highly compacted pyriform nucleus of the mature ...

Journal: :Journal of morphology 2010
Kevin M Gribbins Justin L Rheubert Marla L Anzalone Dustin S Siegel David M Sever

To date multiple studies exist that examine the morphology of spermatozoa. However, there are limited numbers of data detailing the ontogenic characters of spermiogenesis within squamates. Testicular tissues were collected from Cottonmouths (Agkistrodon piscivorus) and tissues from spermiogenically active months were analyzed ultrastructurally to detail the cellular changes that occur during sp...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2003
Wei Yan Lang Ma Kathleen H Burns Martin M Matzuk

Chromatin remodeling is a major event that occurs during mammalian spermiogenesis, the process of spermatid maturation into spermatozoa. Nuclear condensation during spermiogenesis is accomplished by replacing somatic histones (linker histone H1 and core histones) and the testis-specific linker histone, H1t, with transition proteins and protamines. It has long been thought that H1t is the only t...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2006
Shane T Grivna Brook Pyhtila Haifan Lin

Noncoding small RNAs have emerged as important regulators of gene expression at both transcriptional and posttranscriptional levels. Particularly, microRNA (miRNA)-mediated translational repression involving PIWI/Argonaute family proteins has been widely recognized as a novel mechanism of gene regulation. We previously reported that MIWI, a murine PIWI family member, is required for initiating ...

2012
Marie Cibois Gaella Boulanger Yann Audic Luc Paillard Carole Gautier-Courteille

BACKGROUND The first wave of spermatogenesis in mammals is characterized by a sequential and synchronous appearance of germ cells in the prepubertal testis. Post-transcriptional controls of gene expression play important roles in this process but the molecular actors that underlie them are poorly known. METHODOLOGY/PRINCIPAL FINDINGS We evaluated the requirement for the RNA-binding protein CE...

Journal: :Journal of Cell Biology 1969

Journal: :Human reproduction 2003
Elisabeth Carlsen Anna-Maria Andersson Jørgen Holm Petersen Niels E Skakkebaek

BACKGROUND The purpose of this study was to analyse the effect of a history of febrile illness on semen quality. METHODS Twenty-seven healthy men (median age 24.4 years) were followed with monthly semen samples and a daily record of the occurrence of experienced febrile episodes over a 16 month period between March 1998 and June 1999 in Copenhagen, Denmark. Semen samples were analysed for sem...

2011
Futoshi Yazama Akihiro Tai

BACKGROUND Heat shock severely affects sperm production (spermatogenesis) and results in a rapid loss of haploid germ cells, or in other words, sperm formation (spermiogenesis) is inhibited. However, the mechanisms behind the effects of heat shock on spermatogenesis are obscure. METHODOLOGY/PRINCIPAL FINDINGS To identify the inhibitory factor of spermiogenesis, experimental cryptorchid (EC) m...

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