Search results for "Sperm"
showing 10 items of 658 documents
Organometallic complexes with biological molecules. XVIII. Alkyltin(IV) cephalexinate complexes: synthesis, solid state and solution phase investigat…
2004
Abstract Dialkyltin(IV) and trialkyltin(IV) complexes of the deacetoxycephalo-sporin-antibiotic cephalexin [7-( d -2-amino-2-phenylacetamido)-3-methyl-3-cephem-4-carboxylic acid] (Hceph) have been synthesized and investigated both in solid and solution phase. Analytical and thermogravimetric data supported the general formula Alk 2 SnOHceph · H 2 O and Alk 3 Snceph · H 2 O (Alk=Me, n -Bu), while structural information has been gained by FT-IR, 119 Sn Mossbauer and 1 H, 13 C, 119 Sn NMR data. In particular, IR results suggested polymeric structures both for Alk 2 SnOHceph · H 2 O and Alk 3 Snceph · H 2 O. Moreover, cephalexin appears to behave as monoanionic tridentate ligand coordinating th…
Plasma membrane Ca2+ ATPase 4 is required for sperm motility and male fertility.
2004
Calcium and Ca(2+)-dependent signals play a crucial role in sperm motility and mammalian fertilization, but the molecules and mechanisms underlying these Ca(2+)-dependent pathways are incompletely understood. Here we show that homozygous male mice with a targeted gene deletion of isoform 4 of the plasma membrane calcium/calmodulin-dependent calcium ATPase (PMCA), which is highly enriched in the sperm tail, are infertile due to severely impaired sperm motility. Furthermore, the PMCA inhibitor 5-(and-6)-carboxyeosin diacetate succinimidyl ester reduced sperm motility in wild-type animals, thus mimicking the effects of PMCA4 deficiency on sperm motility and supporting the hypothesis of a pivot…
Computer assisted morphometric analysis of ram sperm heads: Evaluation of different fixative techniques
1998
The recent development of automated systems for morphometric sperm head analysis has provided a series of objective parameters which have facilitated the standardization of morphological semen evaluation. This current work attempts to establish the optimum fixing conditions for the morphometric characterization of ram spermatozoa. Ejaculates were obtained from 5 Merino rams used for periodic collection of semen and were diluted at 1:50 with TEST medium. Air-dried smears were fixed either in ethanol-ether (1:1), 50% methanol, 2% glutaraldehyde or SUZA fixative, in which case the smear was pretreated with chloramine. The samples were then stained with commercial kit Hemacolor. Once the prepar…
Mass spectrometric identification of the amino donor and acceptor sites in a transglutaminase protein substrate secreted from rat seminal vesicles.
1991
Four different transglutaminase-modified forms of a protein secreted by the rat seminal vesicles (SV-IV) were synthesized in vitro and characterized. FAB maps of both the native protein and its derivatives, produced by the purified guinea pig liver enzyme in the presence or absence of the polyamine spermidine, were obtained by mass spectrometric analysis after proteolytic digestions. Two differently derivatized SV-IV molecular forms, both possessing only one glutamine residue out of two (Gln-86) cross-linked to endogenous lysine residues, were produced when spermidine was omitted from the reaction mixture: (i) an insoluble homopolymer in which Lys-2, -4, -59, -78, -79, and -80 were involved…
Different micrococcal nuclease cleavage patterns characterize transcriptionally active and inactive sea-urchin histone genes.
1986
Micrococcal nuclease (MNase) and DNaseI have made a great contribution to our present understanding of the structural organization of the eucaryotic genome [l - 31. The enhanced sensitivity of active portions of the genome to DNaseI gave, in fact, the first indication of differences in the nucleoproteic arrangement of the transcribed as compared to the silent DNA regions [4]. The use of MNase, as a probe of the chromatin organization of specific genes in the active and inactive state, provided additional evidence for this and further showed that the packing of several coding segments of DNA in a regular array of nucleosomal particles is severely but reversibly affected by the transcriptiona…
The murine nuclear orphan receptor GCNF is expressed in the XY body of primary spermatocytes
1998
AbstractWe have studied the expression of the nuclear orphan receptor GCNF (germ cell nuclear factor) on the mRNA and protein level in pubertal and adult mouse testes. We show by Northern and Western blot analyses and by in situ hybridization that GCNF is expressed in spermatocytes and round spermatids of adult mouse testis suggesting that GCNF may be a transcriptional regulator of spermatogenesis. Since the GCNF protein is accumulated in the XY body of late pachytene spermatocytes, it may be involved in transcriptional inactivation of sex chromosomes.
Efficiency of transgenesis using sperm-mediated gene transfer: generation of hDAF transgenic pigs.
2000
SINCE the beginning of this century, replacement of failing human organs with their animal counterparts has been an interesting topic of debate for writers and scientists. In the 1960s, prolonged survival after kidney transplantation from chimpanzee to human was obtained in the United States and Europe. Nevertheless, both the progressive improvement in surgical technique and in immunosuppressant therapy and the availability of cadaveric organs and living donation have reduced the interest in xenotransplantation. Because of the increasing requests for organs and the lack of donors to meet that need, xenotransplantation has become a reliable option again for temporary organ replacement (eg, o…
Human somatic cells subjected to genetic induction with six germ line-related factors display meiotic germ cell-like features
2016
AbstractThe in vitro derivation of human germ cells has attracted interest in the last years, but their direct conversion from human somatic cells has not yet been reported. Here we tested the ability of human male somatic cells to directly convert into a meiotic germ cell-like phenotype by inducing them with a combination of selected key germ cell developmental factors. We started with a pool of 12 candidates that were reduced to 6, demonstrating that ectopic expression of the germ line-related genes PRDM1, PRDM14, LIN28A, DAZL, VASA and SYCP3 induced direct conversion of somatic cells (hFSK (46, XY) and hMSC (46, XY)) into a germ cell-like phenotype in vitro. Induced germ cell-like cells …
The human X chromosome is enriched for germline genes expressed in premeiotic germ cells of both sexes.
2006
The role of X-chromosomal genes in spermatogenesis has been subject to a number of studies in different organisms. Recently, it was proposed that the X chromosome has a predominant role in premeiotic stages of mammalian spermatogenesis. We analyzed the expression of a representative set of 17 X-linked and 48 autosomal germline-restricted genes in different stages of human germ cell development. In accordance with data from other species, we show that the human X chromosome is indeed significantly enriched for genes activated in premeiotic stages of spermatogenesis. In contrast to recent studies, however, we found that expression of these genes is not restricted to spermatogenesis, but is ac…
Creating a conditional mutation of Wnt-1 by antisense transgenesis provides evidence that Wnt-1 is not essential for spermatogenesis.
1993
We have used mice transgenic for an antisense construct for Wnt-1 to study the role of this gene in post-meiotic sperm development. The human PGK-2 promoter provided levels of Wnt-1 antisense mRNA in testes in 5 transgenic lines greatly in excess of Wnt-1 mRNA concentrations, and Wnt-1 mRNA levels were greatly decreased in the lines, by 98% in three of them. There was a general correlation between copy number of the insert, levels of antisense RNA, and decreases in mRNA. There was little effect of the antisense transgene on fertility or testicular histology suggesting that normal levels of Wnt-1 transcript are not essential for spermatogenesis.