Effects of pivalic acid and sodium pivalate on L-carnitine concentrations in the cauda epididymidis and on male fertility in the hamster

1997 ◽  
Vol 9 (4) ◽  
pp. 427 ◽  
Author(s):  
L. M. Lewin ◽  
S. Fournier-Delpech ◽  
R. Weissenberg ◽  
R. Golan ◽  
T. Cooper ◽  
...  

In this study, administration of pivalic acid or its sodium salt was found to decrease the L-carnitine concentration in the epididymal lumen of the hamster; it also tested whether this decrease affected sperm cell motility, chromatin structure, or fertilizing capacity. Provision of pivalic acid or its sodium salt (20 mM or 40 mM) in the drinking water of mature male golden hamsters for 30 days reduced (by 72%, 75%, and 83% in three experiments) the L-carnitine concentration of the cauda epididymidis but did not inhibit sperm chromatin condensation, as assessed by flow cytometry. The treatments did not alter the location of motile sperm in the epididymidis nor did they appreciably affect the motility of sperm obtained from the distal cauda epididymidis. The numbers and percentage of ova that reached the 2-cell stage 36–40 h after uterine insemination with spermatozoa from control and treated hamsters served as a measure of sperm fertility. Treatment with pivalic acid or sodium pivalate did not render male hamsters infertile although it appeared to reduce the fertilizing ability of their spermatozoa. These results suggest that the high concentration of L-carnitine present in the lumen of the cauda epididymidis is not required for maturation of sperm chromatin or development of sperm motility.

2005 ◽  
Vol 17 (6) ◽  
pp. 611 ◽  
Author(s):  
M. Bauer ◽  
C. Leigh ◽  
E. Peirce ◽  
W. G. Breed

In most mammals, post-testicular sperm maturation is completed in the caput and corpus epididymides, with storage occurring in the cauda epididymides. However, in the spinifex hopping mouse, Notomys alexis, epididymal sperm transit is rapid and some sperm storage occurs in the distal region of the vas deferens. The aim of the present study was to determine whether the rapid progression of sperm into the vas deferens in the hopping mouse results in late sperm maturation. To determine this, sperm nuclei from the epididymides and vasa deferentia of laboratory and hopping mice were compared for: (1) thiol content after staining with monobromobimane (mBBr); (2) chromatin resistance to acid denaturation following incubation with acetic alcohol and staining with acridine orange; and (3) chromatin resistance to in vitro decondensation after incubation with 1% sodium dodecyl sulfate (SDS). It was found that, whereas laboratory mouse sperm completed chromatin condensation by the time they reached the cauda epididymidis, hopping mouse sperm nuclei from the vas deferens showed significantly less mBBr fluorescence and a greater proportion of sperm were resistant to decondensation with SDS than those in the cauda epididymidis. Therefore, the results of the present study indicate that, unlike in the laboratory mouse, hopping mouse chromatin condensation of spermatozoa continues in the vas deferens and this may be due, at least in part, to rapid epididymal transit.


Genetics ◽  
1993 ◽  
Vol 134 (1) ◽  
pp. 293-308 ◽  
Author(s):  
S R Russell ◽  
K Kaiser

Abstract We have identified of set of related transcripts expressed in the germ line of male Drosophila melanogaster. Surprisingly, while one of the corresponding genes is autosomal the remainder are located on the Y chromosome. The autosomal locus, at 77F on chromosome arm 3L, corresponds to the previously described transcription unit 18c, located in the first intron of the gene for an RI subunit of cAMP-dependent protein kinase. The Y chromosome copies have been mapped to region h18-h19 on the cytogenetic map of the Y outside of any of the regions required for male fertility. In contrast to D. melanogaster, where Y-linked copies were found in nine different wild-type strains, no Y-linked copies were found in sibling species. Several apparently Y-derived cDNA clones and one Y-linked genomic clone have been sequenced. The Y-derived genomic DNA shares the same intron/exon structure as the autosomal copy as well as related flanking sequences suggesting that it transposed to the Y from the autosomal locus. However, this particular Y-linked copy cannot encode a functional polypeptide due to a stop codon at amino acid position 72. Divergence among five different cDNA clones ranges from 1.5 to 6% and includes a large number of third position substitutions. We have not yet obtained a full-length cDNA from a Y-linked gene and therefore cannot conclude that the D. melanogaster Y chromosome contains functional protein-coding genes. The autosomal gene encodes a predicted polypeptide with 45% similarity to histones of the H5 class and more limited similarity to cysteine-rich protamines. This protein may be a distant relative of the histone H1 family perhaps involved in sperm chromatin condensation.


2006 ◽  
Vol 23 (8) ◽  
pp. 1729-1735 ◽  
Author(s):  
Noboru Okamura ◽  
Shuichi Ohnishi ◽  
Hiroyuki Shimaoka ◽  
Ryo Norikura ◽  
Hiroshi Hasegawa

1990 ◽  
Vol 2 (1) ◽  
pp. 35 ◽  
Author(s):  
RG Wales ◽  
J Hunter

Electrophoretic separation of solubilized embryos incubated for 24 h in the presence of [U-14C]glucose indicated incorporation of glucose carbon into a number of protein bands. Treatment of nitrocellulose blots of electrophoretograms with glucosidases had no effect on incorporated counts, confirming that the labelled bands were not due to protein bound glycogen. Furthermore, addition of 0.1 microgram mL-1 tunicamycin to the incubation medium virtually eliminated incorporation of glucose into the protein bands but had no effect on the pattern or rate of incorporation of labelled amino acids in parallel experiments. Also the pattern of labelling of protein by glucose was reflected in the pattern of binding of Con A to the nitrocellulose blots. There were quantitative and qualitative changes in labelling as development progressed. For embryos cultured from the 2-cell stage, a small amount of label was incorporated in two major bands at relative mobility (Mr) 69 and 97 K. With culture from the 8-cell stage, three additional major bands (33, 44 and 56 K) were labelled. Embryos cultured from the morula stage showed a different profile of incorporation; there was much more active labelling, and eight major and a number of minor radioactive bands were identified. Whilst tunicamycin suppressed glucose incorporation into glycoproteins and inhibited compaction of embryos, it had little effect on other parameters of metabolism during incubation in its presence for 24 h. No significant effects of the metabolite on protein synthesis, glycogen storage, lactate production or overall macromolecular synthesis were evident. By contrast, the anabolic metabolism of embryos decompacted by long periods of exposure to tunicamycin was severely reduced although glycolysis was still unaffected. Amphomycin at very high concentration (500 micrograms mL-1) was toxic to embryos but at concentrations up to 250 micrograms mL-1 had no effect on compaction and development of blastocysts. Addition of monensin to the incubation medium [16 micrograms mL-1] did not interfere with the development of either 2-cell or 8-cell embryos to blastocysts.


2010 ◽  
Vol 22 (1) ◽  
pp. 310 ◽  
Author(s):  
M. I. Carretero ◽  
S. Giuliano ◽  
A. Agüero ◽  
M. Pinto ◽  
M. Miragaya ◽  
...  

Guanacos, a wild species of South American camelids, have a high-quality fiber with great economic potential. To evaluate reproductive aptitude in guanacos, our laboratory has developed a reliable semen collection technique using electroejaculation and has applied various methods for evaluating semen characteristics. Studies for evaluating the state of sperm chromatin have also been initiated. Toluidine blue (TB) is a cationic stain that unites with the phosphate groups in the DNA, thus permitting differentiation between sperm heads according to the degree of chromatin decondensation. The objectives of this study were to determine the TB staining patterns of guanaco sperm chromatin, establish a positive control for the stain, and evaluate the effect of collagenase on sperm chromatin condensation. Semen was collected from 4 guanacos, between 6 and 9 years old, using electroejaculation. In Experiment 1, to establish a positive control for the stain, equal quantities of 1% dithiothreitol (DTT) and raw semen were incubated at room temperature for 30 s, 1.5 min, and 3 min. After incubation, smears were made and then dried, to avoid continuing the reaction, and finally were stained with 0.02% TB. A split-plot design was used with time as the splitting factor and considering the males as a block. In Experiment 2, raw semen was divided into 2 aliquots, one diluted 4 : 1 in 0.1% collagenase in HEPES-TALP-BSA medium and the other left without enzyme. Both aliquots were incubated 4 min at 37°C and, after centrifugation to remove the enzyme, smears were made and stained with TB. Spermatozoa were classified according to the degree of chromatin decondensation. Analysis of variance was performed using the males as a blocking factor and the treatment as a fixed factor. According to the degree of chromatin decondensation, three patterns of staining with TB were observed: light blue (negative, without alteration of chromatin condensation), light violet (intermediate, some degree of decondensation), and dark violet (positive, high degree of decondensation). A significant increase (P < 0.05) of sperm with highly decondensed chromatin was observed in semen incubated for 3 min with DTT when compared to 30 s of incubation. Therefore, 3 min of incubation with DTT was chosen as the positive control for Experiment 2. No significant differences in any of the 3 patterns of TB staining were observed between semen incubated with or without 0.1% collagenase. In conclusion, it is possible to use TB to evaluate the degree of chromatin decondensation in guanaco spermatozoa and to use DTT as a positive control for the stain. Treatment of guanaco semen with 0.1% collagenase did not affect sperm chromatin condensation; therefore, this enzyme can be used to decrease semen viscosity and aid handling in the laboratory.


2020 ◽  
Vol 21 (9) ◽  
pp. 3117 ◽  
Author(s):  
Teresa Chioccarelli ◽  
Francesco Manfrevola ◽  
Veronica Porreca ◽  
Silvia Fasano ◽  
Lucia Altucci ◽  
...  

The cannabinoid receptor CB1 regulates differentiation of spermatids. We recently characterized spermatozoa from caput epididymis of CB1-knock-out mice and identified a considerable number of sperm cells with chromatin abnormality such as elevated histone content and poorly condensed chromatin. In this paper, we extended our findings and studied the role of CB1 in the epididymal phase of chromatin condensation of spermatozoa by analysis of spermatozoa from caput and cauda epididymis of wild-type and CB1-knock-out mouse in both a homozygous or heterozygous condition. Furthermore, we studied the impact of CB1-gene deletion on histone displacement mechanism by taking into account the hyperacetylation of histone H4 and players of displacement such as Chromodomain Y Like protein (CDYL) and Bromodomain testis-specific protein (BRDT). Our results show that CB1, via local and/or endocrine cell-to-cell signaling, modulates chromatin remodeling mechanisms that orchestrate a nuclear condensation extent of mature spermatozoa. We show that CB1-gene deletion affects the epididymal phase of chromatin condensation by interfering with inter-/intra-protamine disulphide bridges formation, and deranges the efficiency of histone removal by reducing the hyper-acetylation of histone H4. This effect is independent by gene expression of Cdyl and Brdt mRNA. Our results reveal a novel and important role for CB1 in sperm chromatin condensation mechanisms.


2011 ◽  
Vol 96 (3) ◽  
pp. S173-S174
Author(s):  
Y.-S. Park ◽  
M.K. Kim ◽  
S.-H. Lee ◽  
J.W. Cho ◽  
I.O. Song ◽  
...  

1997 ◽  
Vol 137 (1) ◽  
pp. 183-192 ◽  
Author(s):  
Xuequn Helen Hua ◽  
Hong Yan ◽  
John Newport

Using cell-free extracts made from Xenopus eggs, we show that cdk2-cyclin E and A kinases play an important role in negatively regulating DNA replication. Specifically, we demonstrate that the cdk2 kinase concentration surrounding chromatin in extracts increases 200-fold once the chromatin is assembled into nuclei. Further, we find that if the cdk2–cyclin E or A concentration in egg cytosol is increased 16-fold before the addition of sperm chromatin, the chromatin fails to initiate DNA replication once assembled into nuclei. This demonstrates that cdk2–cyclin E or A can negatively regulate DNA replication. With respect to how this negative regulation occurs, we show that high levels of cdk2–cyclin E do not block the association of the protein complex ORC with sperm chromatin but do prevent association of MCM3, a protein essential for replication. Importantly, we find that MCM3 that is prebound to chromatin does not dissociate when cdk2– cyclin E levels are increased. Taken together our results strongly suggest that during the embryonic cell cycle, the low concentrations of cdk2–cyclin E present in the cytosol after mitosis and before nuclear formation allow proteins essential for potentiating DNA replication to bind to chromatin, and that the high concentration of cdk2–cyclin E within nuclei prevents MCM from reassociating with chromatin after replication. This situation could serve, in part, to limit DNA replication to a single round per cell cycle.


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