scholarly journals Sex Determination and Differentiation in Teleost: Roles of Genetics, Environment, and Brain

Biology ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 973
Author(s):  
Preetha Rajendiran ◽  
Faizul Jaafar ◽  
Sonika Kar ◽  
Chenichery Sudhakumari ◽  
Balasubramanian Senthilkumaran ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Sex Determination ◽  
Developmental Process ◽  
Sex Differentiation ◽  
Reproductive Organ ◽  
Cellular Level ◽  
Complex Biological System ◽  
Species Specific ◽  
The Brain

The fish reproductive system is a complex biological system. Nonetheless, reproductive organ development is conserved, which starts with sex determination and then sex differentiation. The sex of a teleost is determined and differentiated from bipotential primordium by genetics, environmental factors, or both. These two processes are species-specific. There are several prominent genes and environmental factors involved during sex determination and differentiation. At the cellular level, most of the sex-determining genes suppress the female pathway. For environmental factors, there are temperature, density, hypoxia, pH, and social interaction. Once the sexual fate is determined, sex differentiation takes over the gonadal developmental process. Environmental factors involve activation and suppression of various male and female pathways depending on the sexual fate. Alongside these factors, the role of the brain during sex determination and differentiation remains elusive. Nonetheless, GnRH III knockout has promoted a male sex-biased population, which shows brain involvement during sex determination. During sex differentiation, LH and FSH might not affect the gonadal differentiation, but are required for regulating sex differentiation. This review discusses the role of prominent genes, environmental factors, and the brain in sex determination and differentiation across a few teleost species.

scholarly journals Impaired Mitophagy in Neurons and Glial Cells during Aging and Age-Related Disorders

2021 ◽  
Vol 22 (19) ◽  
pp. 10251
Author(s):  
Vladimir Sukhorukov ◽  
Dmitry Voronkov ◽  
Tatiana Baranich ◽  
Natalia Mudzhiri ◽  
Alina Magnaeva ◽  
...  
Keyword(s):  
Glial Cells ◽  
Brain Aging ◽  
Cellular Level ◽  
Aging Brain ◽  
The Past ◽  
Age Related ◽  
Accumulation Of Damage ◽  
Quantity Control ◽  
The Brain

Aging is associated with a decline in cognitive function, which can partly be explained by the accumulation of damage to the brain cells over time. Neurons and glia undergo morphological and ultrastructure changes during aging. Over the past several years, it has become evident that at the cellular level, various hallmarks of an aging brain are closely related to mitophagy. The importance of mitochondria quality and quantity control through mitophagy is highlighted by the contribution that defects in mitochondria–autophagy crosstalk make to aging and age-related diseases. In this review, we analyze some of the more recent findings regarding the study of brain aging and neurodegeneration in the context of mitophagy. We discuss the data on the dynamics of selective autophagy in neurons and glial cells during aging and in the course of neurodegeneration, focusing on three mechanisms of mitophagy: non-receptor-mediated mitophagy, receptor-mediated mitophagy, and transcellular mitophagy. We review the role of mitophagy in neuronal/glial homeostasis and in the molecular pathogenesis of neurodegenerative disorders, such as Parkinson’s disease, Alzheimer’s disease, and other disorders. Common mechanisms of aging and neurodegeneration that are related to different mitophagy pathways provide a number of promising targets for potential therapeutic agents.

Hypothalamic neurohormonal agents and sexual maturation of immature female rats

1961 ◽  
Vol 201 (6) ◽  
pp. 1176-1180 ◽  
Author(s):  
Alan Corbin ◽  
B. A. Schottelius
Keyword(s):  
Reproductive Organ ◽  
Female Rats ◽  
Albino Rats ◽  
Immature Female ◽  
Organ Growth ◽  
Hypophysectomized Rats ◽  
Bilateral Destruction ◽  
The Brain ◽  
Normal Controls

The possible role of four recognized hypothalamic constituents in activation and maturation of the hypophysial-reproductive organ complex of immature female albino rats was investigated. Normal and hypophysectomized rats and rats with bilateral destruction of an area extending from the ventromedial nucleus to mammillary body were studied. Animals were injected either with 70 milliunits of antidiuretic hormone (ADH), 70 milluniits of oxytocin, 25 µg of serotonin, or 2 µg of epinephrine every 5th day, from age 20 through 45 days, via a cannula permanently implanted in the 3rd ventricle of the brain. No response to ADH was observed. Oxytocin accelerated vaginal canalization and caused premature reproductive organ growth in normal recipients. Whereas lesioned untreated controls remained sexually retarded, vaginal opening and reproductive organ growth equivalent to 50-day-old sham-operated controls were induced in lesioned animals by oxytocin administration. Serotonin prevented maturation in normal controls, but was ineffective in lesioned animals. Hypophysectomized rats were unresponsive to any agent injected. The results imply that oxytocin may directly activate the hypophysis of immature female rats. Serotonin, on the other hand, inhibits the hypophysial-gonadal axis of these animals, but its effects probably are relayed via the hypothalamus.

scholarly journals Role of Alternative Splicing in Sex Determination in Vertebrates

2021 ◽  
pp. 1-11
Author(s):  
Isabel Gómez-Redondo ◽  
Benjamín Planells ◽  
Paula Navarrete ◽  
Alfonso Gutiérrez-Adán
Keyword(s):  
Alternative Splicing ◽  
Sex Determination ◽  
Transcription Initiation ◽  
Time Window ◽  
Gonad Development ◽  
Reproductive Organ ◽  
Mrna Splicing ◽  
Transcriptional Level ◽  
Splicing Regulators

During the process of sex determination, a germ-cell-containing undifferentiated gonad is converted into either a male or a female reproductive organ. Both the composition of sex chromosomes and the environment determine sex in vertebrates. It is assumed that transcription level regulation drives this cascade of mechanisms; however, transcription factors can alter gene expression beyond transcription initiation by controlling pre-mRNA splicing and thereby mRNA isoform production. Using the key time window in sex determination and gonad development in mice, it has been reported that new non-transcriptional events, such as alternative splicing, could play a key role in sex determination in mammals. We know the role of key regulatory factors, like WT1(+/–KTS) or FGFR2(b/c) in pre-mRNA splicing and sex determination, indicating that important steps in the vertebrate sex determination process probably operate at a post-transcriptional level. Here, we discuss the role of pre-mRNA splicing regulators in sex determination in vertebrates, focusing on the new RNA-seq data reported from mice fetal gonadal transcriptome.

scholarly journals Multiple sclerosis: environmental risk factors

1998 ◽  
Vol XXX (1-2) ◽  
pp. 40-42
Author(s):  
Enrico Granieri ◽  
Ilaria Casetta
Keyword(s):  
Risk Factors ◽  
Multiple Sclerosis ◽  
Spinal Cord ◽  
Environmental Factors ◽  
Environmental Risk ◽  
Biological Significance ◽  
Unknown Etiology ◽  
Brain And Spinal Cord ◽  
The Brain

Multiple sclerosis is a disease of unknown etiology characterized by inflammory demyelination of the brain and spinal cord. Epidemiological investigations play important role in study of multiple sclerosis. Geographical distribution of the disease has been described in terms of prevalence and incidence. The possible role of environmental factors as a cause of multiple sclerosis had been hypothesized with observation of unequal geographic distribution of the disease. More interesting, in terms of their biological significance, are attempts to identify associations between multiple sclerosis and situations or events wich could cause blood-brain barrier damages, such as trauma or toxic exposures.

scholarly journals Expression of a Rap2.12 like-1 ERF gene during adventitious rooting of chestnut and oak microshoots

2020 ◽  
Vol 67 (1-2) ◽  
pp. 69-82
Author(s):  
Silvia Valladares ◽  
Elena Varas ◽  
Jesús M. Vielba ◽  
Nieves Vidal ◽  
Veronica Codesido ◽  
...  
Keyword(s):  
Developmental Process ◽  
Root Apex ◽  
Adventitious Rooting ◽  
Gene Encoding ◽  
Endogenous Factors ◽  
Rooting Of Cuttings ◽  
Auxin Transport Inhibitor ◽  
Species Specific

Adventitious rooting of cuttings is a complex developmental process in forest species, with several exogenous and endogenous factors influencing the outcome of the process. In this study we applied an in vitro working system, comprising two lines of microshoots with the same genotype but at a different ontogenetic stages, in two different tree species (chestnut and oak). We analyzed the expression of a gene encoding an AP2/ERF transcription factor from group VII in the initial hours of the adventitious rooting induction, both in rooting competent and incompetent microshoots. The analysis revealed that expression of this gene is related to wounding, ontogenetic stage and auxin in a complex and species-specific manner. Putative induction of the gene by auxin was also analyzed in the presence of naphthyl-phthalamic acid (NPA), an auxin transport inhibitor. In situ expression analysis in chestnut relates the gene activity to cambial divisions and root primordia in rooting competent microshoots, as well as in the root apex. The putative role of the gene during adventitious roots formation is discussed.

scholarly journals Species-Specific Features of Neuron-Glial Populations in the Brain of Tailless Amphibians

2019 ◽  
pp. 445-459
Author(s):  
Liubov’ N. Afanaskina ◽  
Nadezhda N. Medvedeva
Keyword(s):  
Brain Regions ◽  
Bufo Bufo ◽  
Cellular Level ◽  
The Body ◽  
Rana Arvalis ◽  
Species Specific ◽  
The Relationship ◽  
The Brain ◽  
Tailless Amphibians

The midbrain roof and cerebellum cortex are the main integrative centers in amphibians. They serve to analyze and process nerve impulses, form the organism’s response, regulate and coordinate movements, connect amphibians with their environments. The present study addresses the relationship between the species of the tailless amphibians inhabiting the southern part of the Krasnoyarsk region (Bufo bufo Linnaeus, Rana arvalis Nilsson, Pelophylax ridibundus Pallas, and Rana amurensis Boulenger) and the morphological parameters of the populations of neurons and glia in layer VI of the midbrain roof and layers of the cerebellum cortex. The species-specific structure of amphibians’ brain regions has been found to be evident not only at the organ level (size and shape), but also at the level of the organization of neuron and glial cell populations. Distinctive species-specific differences can be found in the parameters of cell area (the area of the body, the area of the nucleus and the area of the cytoplasm) and the distribution density of neurons and gliocytes. The development of specific morphological features at the cellular level of the arrangement of the midbrain and cerebellum layers in different species of tailless amphibians is associated with long-term phylogenetic transformations of their nervous system and adaptation of amphibians to the terrestrial-aquatic habitat

scholarly journals Thyroid hormone and the central control of homeostasis

2012 ◽  
Vol 49 (1) ◽  
pp. R29-R35 ◽  
Author(s):  
Amy Warner ◽  
Jens Mittag
Keyword(s):  
Thyroid Hormone ◽  
Molecular Mechanisms ◽  
Cellular Level ◽  
Autonomic Control ◽  
Direct Effects ◽  
Energy Turnover ◽  
Thyroid Hormone Action ◽  
The Brain ◽  
Hormone Signalling

It has long been known that thyroid hormone has profound direct effects on metabolism and cardiovascular function. More recently, it was shown that the hormone also modulates these systems by actions on the central autonomic control. Recent studies that either manipulated thyroid hormone signalling in anatomical areas of the brain or analysed seasonal models with an endogenous fluctuation in hypothalamic thyroid hormone levels revealed that the hormone controls energy turnover. However, most of these studies did not progress beyond the level of anatomical nuclei; thus, the neuronal substrates as well as the molecular mechanisms remain largely enigmatic. This review summarises the evidence for a role of thyroid hormone in the central autonomic control of peripheral homeostasis and advocates novel strategies to address thyroid hormone action in the brain on a cellular level.

scholarly journals Functional Mature Human Microglia Developed in Human iPSC Microglial Chimeric Mouse Brain

2019 ◽  
Author(s):  
Ranjie Xu ◽  
Andrew J. Boreland ◽  
Xiaoxi Li ◽  
Anthony Posyton ◽  
Kelvin Kwan ◽  
...  
Keyword(s):  
Mouse Brain ◽  
Disease Risk ◽  
Expression Patterns ◽  
Chimeric Mouse ◽  
Post Transplantation ◽  
Human Microglia ◽  
Species Specific ◽  
Human Ipsc ◽  
The Brain

AbstractMicroglia, the brain-resident macrophages, exhibit highly dynamic functions in neurodevelopment and neurodegeneration. Human microglia possess unique features as compared to mouse microglia, but our understanding of human microglial functions is largely limited by an inability to obtain human microglia under homeostatic states. We developed a human pluripotent stem cell (hPSC)-based microglial chimeric mouse brain model by transplanting hPSC-derived primitive macrophage precursors into neonatal mouse brains. The engrafted human microglia widely disperse in the brain and replace mouse microglia in corpus callosum at 6 months post-transplantation. Single-cell RNA-sequencing of the microglial chimeric mouse brains reveals that xenografted hPSC-derived microglia largely retain human microglial identity, as they exhibit signature gene expression patterns consistent with physiological human microglia and recapitulate heterogeneity of adult human microglia. Importantly, the engrafted hPSC-derived microglia exhibit dynamic response to cuprizone-induced demyelination and species-specific transcriptomic differences in the expression of neurological disease-risk genes in microglia. This model will serve as a novel tool to study the role of human microglia in brain development and degeneration.

scholarly journals Stress and the Role of the Gut–Brain Axis in the Pathogenesis of Schizophrenia: A Literature Review

2021 ◽  
Vol 22 (18) ◽  
pp. 9747
Author(s):  
Behnam Vafadari
Keyword(s):  
Environmental Factors ◽  
Life Events ◽  
Psychosocial Stress ◽  
Social Stress ◽  
Stressful Life Events ◽  
Review Article ◽  
Main Interest ◽  
City Life ◽  
The Brain

Schizophrenia is a severe neuropsychiatric disorder, and its etiology remains largely unknown. Environmental factors have been reported to play roles in the pathogenesis of schizophrenia, and one of the major environmental factors identified for this disorder is psychosocial stress. Several studies have suggested that stressful life events, as well as the chronic social stress associated with city life, may lead to the development of schizophrenia. The other factor is the gut–brain axis. The composition of the gut microbiome and alterations thereof may affect the brain and may lead to schizophrenia. The main interest of this review article is in overviewing the major recent findings on the effects of stress and the gut–brain axis, as well as their possible bidirectional effects, in the pathogenesis of schizophrenia.

scholarly journals Suppression of P450 aromatase gene expression in sex-reversed males produced by rearing genetically female larvae at a high water temperature during a period of sex differentiation in the Japanese flounder (Paralichthys olivaceus)

1999 ◽  
Vol 23 (2) ◽  
pp. 167-176 ◽  
Author(s):  
T Kitano ◽  
K Takamune ◽  
T Kobayashi ◽  
Y Nagahama ◽  
SI Abe
Keyword(s):  
Gene Expression ◽  
Sex Determination ◽  
Water Temperature ◽  
Sex Differentiation ◽  
High Water ◽  
Japanese Flounder ◽  
Female Group ◽  
High Water Temperature ◽  
Male Group

The phenotypic sex of many teleost fishes including flounders can be experimentally altered by treating embryos or larvae with varied temperatures or sex-steroid hormones. To analyse the sex determination mechanism, especially the role of cytochrome P450 aromatase (P450arom), an enzyme that catalyses the conversion of androgens to estrogens, in temperature-dependent gonadal sex differentiation in the Japanese flounder, we generated two populations of larvae, both having XX (genetic females) but each growing up to display all phenotypic females or males, by rearing the larvae at normal (18 degrees C) or high (27 degrees C) water temperatures from days 30 to 100 after hatching respectively. The larvae (XX) were produced artificially by mating normal females (XX) with gynogenetic diploid males (XX) which had been sex-reversed to phenotypic males by 17alpha-methyltestosterone. To study the role of P450arom in sex determination in the flounder, we first isolated a P450arom cDNA containing the complete open reading frame from the ovary. RT-PCR showed that P450arom mRNA was highly expressed in the ovary and spleen but weakly in the testis and brain. Semi-quantitative analyses of P450arom mRNA in gonads during sex differentiation showed that there was no difference in the levels of P450arom mRNA between the female and male groups when the gonad was sexually indifferent (day 50 after hatching). However, after the initiation of sex differentiation (day 60), the mRNA levels increased rapidly in the female group, whereas they decreased slightly in the male group. Similarly, estradiol-17beta levels rose remarkably in the female group, yet remained constant in the male group. These results suggest that induction of sex reversal of genetically female larvae to phenotypic males by rearing them at a high water temperature caused a suppression of P450arom gene expression. Furthermore, we suggest that the maintenance of P450arom mRNA at very low levels is a prerequisite for testicular differentiation, while the increased levels are indispensable for ovarian differentiation.

Sign in / Sign up

Export Citation Format

Share Document