The molecular basis and reproductive function(s) of copulatory plugs

2016 ◽  
Vol 83 (9) ◽  
pp. 755-767 ◽  
Author(s):  
Marlon R. Schneider ◽  
Rachel Mangels ◽  
Matthew D. Dean
2021 ◽  
Vol 6 (4) ◽  
pp. 142-150
Author(s):  
A. N. Volkov ◽  
L. V. Nacheva

Cytogenetics is an essential part of human genetics which studies the structure of chromosomes and their collection which is called karyotype. Cytogenetic techniques are employed while interrogating DNA organisation and compaction. Analysis of the chromosomal structure contributes to uncovering the molecular basis of various cellular processes in normal and pathological conditions. Furthermore, spectrum and frequency of chromosome abnormalities serves as an indicator of mutagenic effects. Cytogenetic techniques became indispensable for discovering the genetic causes of human diseases at different stages of ontogenesis. Genetic abnormalities are a common cause of impaired reproductive function, abnormal pregnancy, and neonatal malformations. Genetic screening for chromosomal abnormalities and congenital anomalies is a powerful tool for reducing the genetic load in human populations as well as disease, psychological and social burden on families and societies. This paper begins the cycle of lectures on molecular basis of human cytogenetics, cytogenetic techniques, and the corresponding research and clinical applications. The lecture is primarily aimed at biomedical students and physicians who often have an unmet need to analyse and interpret the results of cytogenetic analyses.


Endocrinology ◽  
2014 ◽  
Vol 155 (5) ◽  
pp. 1817-1826 ◽  
Author(s):  
You Lee Son ◽  
Takayoshi Ubuka ◽  
Misato Narihiro ◽  
Yujiro Fukuda ◽  
Itaru Hasunuma ◽  
...  

The inhibitory effect of stress on reproductive function is potentially mediated by high concentrations of circulating glucocorticoids (GCs) acting via the GC receptor (GR). Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that inhibits gonadotropin secretion. GnIH may mediate stress-induced reproductive dysfunction. However, it is not yet known whether GC-bound GR is directly involved in GnIH transcription. Here, we demonstrated the localization of GR mRNA in GnIH neurons in the paraventricular nucleus of quail, suggesting that GC can directly regulate GnIH transcription. We next showed that 24 hours of treatment with corticosterone (CORT) increase GnIH mRNA expression in the quail diencephalon. We further investigated the mechanism of activation of GnIH transcription by CORT using a GnIH-expressing neuronal cell line, rHypoE-23, derived from rat hypothalamus. We found the expression of GR mRNA in rHypoE-23 cells and increased GnIH mRNA expression by 24 hours of CORT treatment. We finally characterized the promoter activity of rat GnIH gene stimulated by CORT. Through DNA deletion analysis, we identified a CORT-responsive region at 2000–1501 bp upstream of GnIH precursor coding region. This region included 2 GC response elements (GREs) at −1665 and −1530 bp. Mutation of −1530 GRE abolished CORT responsiveness. We also found CORT-stimulated GR recruitment at the GnIH promoter region containing the −1530 GRE. These results provide a putative molecular basis for transcriptional activation of GnIH under stress by demonstrating that CORT directly induces GnIH transcription by recruitment of GR to its promoter.


Author(s):  
Ben O. Spurlock ◽  
Milton J. Cormier

The phenomenon of bioluminescence has fascinated layman and scientist alike for many centuries. During the eighteenth and nineteenth centuries a number of observations were reported on the physiology of bioluminescence in Renilla, the common sea pansy. More recently biochemists have directed their attention to the molecular basis of luminosity in this colonial form. These studies have centered primarily on defining the chemical basis for bioluminescence and its control. It is now established that bioluminescence in Renilla arises due to the luciferase-catalyzed oxidation of luciferin. This results in the creation of a product (oxyluciferin) in an electronic excited state. The transition of oxyluciferin from its excited state to the ground state leads to light emission.


Author(s):  
Delbert E. Philpott ◽  
W. Sapp ◽  
C. Williams ◽  
T. Fast ◽  
J. Stevenson ◽  
...  

Space Lab 3 (SL-3) was flown on Shuttle Challenger providing an opportunity to measure the effect of spaceflight on rat testes. Cannon developed the idea that organisms react to unfavorable conditions with highly integrated metabolic activities. Selye summarized the manifestations of physiological response to nonspecific stress and he pointed out that atrophy of the gonads always occurred. Many papers have been published showing the effects of social interaction, crowding, peck order and confinement. Flickinger showed delayed testicular development in subordinate roosters influenced by group numbers, social rank and social status. Christian reported increasing population size in mice resulted in adrenal hypertrophy, inhibition of reproductive maturation and loss of reproductive function in adults. Sex organ weights also declined. Two male dogs were flown on Cosmos 110 for 22 days. Fedorova reported an increase of 30 to 70% atypical spermatozoa consisting of tail curling and/or the absence of a tail.


Author(s):  
Darcy B. Kelley ◽  
Martha L. Tobias ◽  
Mark Ellisman

Brain and muscle are sexually differentiated tissues in which masculinization is controlled by the secretion of androgens from the testes. Sensitivity to androgen is conferred by the expression of an intracellular protein, the androgen receptor. A central problem of sexual differentiation is thus to understand the cellular and molecular basis of androgen action. We do not understand how hormone occupancy of a receptor translates into an alteration in the developmental program of the target cell. Our studies on sexual differentiation of brain and muscle in Xenopus laevis are designed to explore the molecular basis of androgen induced sexual differentiation by examining how this hormone controls the masculinization of brain and muscle targets.Our approach to this problem has focused on a highly androgen sensitive, sexually dimorphic neuromuscular system: laryngeal muscles and motor neurons of the clawed frog, Xenopus laevis. We have been studying sex differences at a synapse, the laryngeal neuromuscular junction, which mediates sexually dimorphic vocal behavior in Xenopus laevis frogs.


1998 ◽  
Vol 33 ◽  
pp. 65-77 ◽  
Author(s):  
Dominique Massotte ◽  
Brigitte L. Kieffer
Keyword(s):  

2011 ◽  
Vol 81 (4) ◽  
pp. 238-239 ◽  
Author(s):  
Manfred Eggersdorfer ◽  
Paul Walter

Nutrition is important for human health in all stages of life - from conception to old age. Today we know much more about the molecular basis of nutrition. Most importantly, we have learnt that micronutrients, among other factors, interact with genes, and new science is increasingly providing more tools to clarify this interrelation between health and nutrition. Sufficient intake of vitamins is essential to achieve maximum health benefit. It is well established that in developing countries, millions of people still suffer from micronutrient deficiencies. However, it is far less recognized that we face micronutrient insufficiencies also in developed countries.


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