scholarly journals Seasonal Changes in Spermatogenesis (Including Germ Cell Degeneration) and Plasma Testosterone Concentration in the Grey-headed Fruit Bat, Pteropus poliocephalus

1987 ◽  
Vol 40 (2) ◽  
pp. 211 ◽  
Author(s):  
MichaeI A McGuckin ◽  
Alan W Blackshaw
Keyword(s):  
Germ Cell ◽  
Breeding Season ◽  
Cell Loss ◽  
Plasma Testosterone ◽  
Cell Degeneration ◽  
Fruit Bat ◽  
Pteropus Poliocephalus ◽  
Maximal Plasma ◽  
Testicular Size ◽  
Tubule Diameter

Maximal testicular size of P. poliocephalus occurred during the February-March-April period (autumn breeding season) associated with maximal plasma levels of testosterone (121' 5 � 23� 4 nmol/I). Testicular size decreased after the breeding season concomitant with a decrease in plasma testosterone (7'6 � 1�7 nmol/I). Histologically, regressive changes were observed in the testis after the breeding season including a decrease in seminiferous tubule diameter and a decrease in Leydig cell nuclear diameter. Significant germ cell loss occurred during the breeding season (44%) mainly during the final spermatogonial division and meiosis and increased in regressed testes (69%), being accentuated chiefly at meiosis. All regressed testes showed some sperm production although it was much reduced after the breeding season; however, optimal fertility appears to be restricted to autumn by the large increases in testosterone secretion which only occur at this time.

scholarly journals Drosophila CG2469 Encodes a Homolog of Human CTR9 and Is Essential for Development

2016 ◽  
Vol 6 (12) ◽  
pp. 3849-3857 ◽  
Author(s):  
Dhananjay Chaturvedi ◽  
Mayu Inaba ◽  
Shane Scoggin ◽  
Michael Buszczak
Keyword(s):  
Germ Cell ◽  
Sequence Similarity ◽  
Cell Loss ◽  
Germline Stem Cell ◽  
Cell Nuclei ◽  
Transcriptional Initiation ◽  
Histone Locus Bodies ◽  
Paf1 Complex ◽  
Histone Locus ◽  
Drosophila Cells

Abstract Conserved from yeast to humans, the Paf1 complex participates in a number of diverse processes including transcriptional initiation and polyadenylation. This complex typically includes five proteins: Paf1, Rtf1, Cdc73, Leo1, and Ctr9. Previous efforts identified clear Drosophila homologs of Paf1, Rtf1, and Cdc73 based on sequence similarity. Further work showed that these proteins help to regulate gene expression and are required for viability. To date, a Drosophila homolog of Ctr9 has remained uncharacterized. Here, we show that the gene CG2469 encodes a functional Drosophila Ctr9 homolog. Both human and Drosophila Ctr9 localize to the nuclei of Drosophila cells and appear enriched in histone locus bodies. RNAi knockdown of Drosophila Ctr9 results in a germline stem cell loss phenotype marked by defects in the morphology of germ cell nuclei. A molecular null mutation of Drosophila Ctr9 results in lethality and a human cDNA CTR9 transgene rescues this phenotype. Clonal analysis in the ovary using this null allele reveals that loss of Drosophila Ctr9 results in a reduction of global levels of histone H3 trimethylation of lysine 4 (H3K4me3), but does not compromise the maintenance of stem cells in ovaries. Given the differences between the null mutant and RNAi knockdown phenotypes, the germ cell defects caused by RNAi likely result from the combined loss of Drosophila Ctr9 and other unidentified genes. These data provide further evidence that the function of this Paf1 complex component is conserved across species.

scholarly journals The developing ovary of the South American plains vizcacha, Lagostomus maximus (Mammalia, Rodentia): massive proliferation with no sign of apoptosis-mediated germ cell attrition

Reproduction ◽  
2011 ◽  
Vol 141 (5) ◽  
pp. 633-641 ◽  
Author(s):  
N P Leopardo ◽  
F Jensen ◽  
M A Willis ◽  
M B Espinosa ◽  
A D Vitullo
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Ovarian Tissue ◽  
Tunel Assay ◽  
South American ◽  
Follicular Atresia ◽  
The South ◽  
Cell Degeneration ◽  
Lagostomus Maximus ◽  
Apoptotic Activity

Apoptosis-dependent massive germ cell death is considered a constitutive trait of the developing mammalian ovary that eliminates 65–85% of the germinal tissue depending on the species. After birth and during adult lifetime, apoptotic activity moves from the germ cell proper to the somatic compartment, decimating germ cells through follicular atresia until the oocyte reserve is exhausted. In contrast, the South American rodent Lagostomus maximus shows suppressed apoptosis-dependent follicular atresia in the adult ovary, with continuous folliculogenesis and massive polyovulation, which finally exhausts the oocyte pool. The absence of follicular atresia in adult L. maximus might arise from a failure to move apoptosis from the germinal stratum to the somatic compartment after birth or being a constitutive trait of the ovarian tissue with no massive germ cell degeneration in the developing ovary. We tested these possibilities by analysing oogenesis, expression of germ cell-specific VASA protein, apoptotic proteins BCL2 and BAX, and DNA fragmentation by TUNEL assay in the developing ovary of L. maximus. Immunolabelling for VASA revealed a massive and widespread colonisation of the ovary and proliferation of germ cells organised in nests that disappeared at late development when folliculogenesis began. No sign of germ cell attrition was found at any time point. BCL2 remained positive throughout oogenesis, whereas BAX was slightly detected in early development. TUNEL assay was conspicuously negative throughout the development. These results advocate for an unrestricted proliferation of germ cells, without apoptosis-driven elimination, as a constitutive trait of L. maximus ovary as opposed to what is normally found in the developing mammalian ovary.

scholarly journals Germ Cell Loss Induced by 12C6+ Ion Irradiation in Young Female Mice

2006 ◽  
Vol 47 (2) ◽  
pp. 131-134 ◽  
Author(s):  
Hong ZHANG ◽  
Xu ZHANG ◽  
Zhigang YUAN ◽  
Xiaoda LI ◽  
Wenjian LI ◽  
...  
Keyword(s):  
Germ Cell ◽  
Ion Irradiation ◽  
Cell Loss ◽  
Young Female ◽  
Female Mice

Changes in androgen concentrations during puberty and their relation to behaviour in male Saccostomus campestris (Gray 1844), an African rodent

1993 ◽  
Vol 5 (5) ◽  
pp. 577 ◽  
Author(s):  
LM Westlin ◽  
HM Dott
Keyword(s):  
Sexual Development ◽  
Plasma Concentrations ◽  
Reproductive Organs ◽  
Oestrous Cycle ◽  
Plasma Testosterone ◽  
Seminiferous Tubules ◽  
Morphological Development ◽  
Intraindividual Variation ◽  
Adult Females ◽  
Tubule Diameter

Sexual development in male Saccostomus campestris, the pouched mouse, was studied in terms of morphological development and changes in concentrations of plasma testosterone and androstenedione. The interaction of adult females and males following the introduction of a male was observed at all stages of the oestrous cycle. The histology of the reproductive organs is similar to that of other rodents. Measurements of the diameter of the seminiferous tubules and the width of the seminiferous epithelium suggest asymptotic growth but, although the diameter had not reached the asymptote at 70 days of age the epithelial width was close to the calculated asymptote at 55 days of age. Intraindividual variation was no greater than variation between individuals of the same age from 55-70 days. Spermatids were not seen in any animals younger than 45 days, but all animals over 55 days of age had spermatozoa in the epididymis. By 70 days of age, fertile matings were observed. At this stage, the seminiferous tubule diameter was still increasing slowly but plasma concentrations of testosterone and androstenedione had reached adult levels; at no time was the concentration of testosterone greater than androstenedione. The males were never aggressive towards females; however, they were severely attacked by females at all stages of the oestrous cycle except pro-oestrus. Only rarely did males show aggression to other males.

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