scholarly journals Individual heterogeneity determines sex differences in mortality in a monogamous bird with reversed sexual dimorphism

2017 ◽  
Vol 86 (4) ◽  
pp. 899-907 ◽  
Author(s):  
Fernando Colchero ◽  
Alix Eva Aliaga ◽  
Owen R. Jones ◽  
Dalia A. Conde
Keyword(s):  
Sex Differences ◽  
Sexual Dimorphism ◽  
Individual Heterogeneity ◽  
Reversed Sexual Dimorphism

scholarly journals Regulatory Role of Sex Hormones in Cardiovascular Calcification

2021 ◽  
Vol 22 (9) ◽  
pp. 4620
Author(s):  
Holly J. Woodward ◽  
Dongxing Zhu ◽  
Patrick W. F. Hadoke ◽  
Victoria E. MacRae
Keyword(s):  
Cardiovascular Disease ◽  
Sex Differences ◽  
Sexual Dimorphism ◽  
Aortic Stenosis ◽  
Sex Hormones ◽  
Sex Hormone ◽  
Increased Risk ◽  
Male Sex ◽  
Primary Male

Sex differences in cardiovascular disease (CVD), including aortic stenosis, atherosclerosis and cardiovascular calcification, are well documented. High levels of testosterone, the primary male sex hormone, are associated with increased risk of cardiovascular calcification, whilst estrogen, the primary female sex hormone, is considered cardioprotective. Current understanding of sexual dimorphism in cardiovascular calcification is still very limited. This review assesses the evidence that the actions of sex hormones influence the development of cardiovascular calcification. We address the current question of whether sex hormones could play a role in the sexual dimorphism seen in cardiovascular calcification, by discussing potential mechanisms of actions of sex hormones and evidence in pre-clinical research. More advanced investigations and understanding of sex hormones in calcification could provide a better translational outcome for those suffering with cardiovascular calcification.

scholarly journals Sex Differences in the Triad of Acquired Sensorineural Hearing Loss

2021 ◽  
Vol 22 (15) ◽  
pp. 8111
Author(s):  
Kuang-Hsu Lien ◽  
Chao-Hui Yang
Keyword(s):  
Hearing Loss ◽  
Sex Differences ◽  
Sexual Dimorphism ◽  
Sensorineural Hearing Loss ◽  
Hormone Replacement ◽  
Modern Society ◽  
Sensorineural Hearing ◽  
Drug Induced ◽  
Age Related ◽  
Age Related Hearing Loss

The triad of noise-generated, drug-induced, and age-related hearing loss is the major cause of acquired sensorineural hearing loss (ASNHL) in modern society. Although these three forms of hearing loss display similar underlying mechanisms, detailed studies have revealed the presence of sex differences in the auditory system both in human and animal models of ASNHL. However, the sexual dimorphism of hearing varies among noise-induced hearing loss (NIHL), ototoxicity, and age-related hearing loss (ARHL). Importantly, estrogen may play an essential role in modulating the pathophysiological mechanisms in the cochlea and several reports have shown that the effects of hormone replacement therapy on hearing loss are complex. This review will summarize the clinical features of sex differences in ASNHL, compare the animal investigations of cochlear sexual dimorphism in response to the three insults, and address how estrogen affects the auditory organ at molecular levels.

scholarly journals Sexual conflict drives micro- and macroevolution of sexual dimorphism in immunity

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Basabi Bagchi ◽  
Quentin Corbel ◽  
Imroze Khan ◽  
Ellen Payne ◽  
Devshuvam Banerji ◽  
...  
Keyword(s):  
Sex Differences ◽  
Sexual Dimorphism ◽  
Mating System ◽  
Sexual Conflict ◽  
Experimental Evolution ◽  
Parasitic Infections ◽  
Pathogen Dynamics ◽  
Trade Offs ◽  
Host Pathogen ◽  
Seed Beetles

Abstract Background Sexual dimorphism in immunity is believed to reflect sex differences in reproductive strategies and trade-offs between competing life history demands. Sexual selection can have major effects on mating rates and sex-specific costs of mating and may thereby influence sex differences in immunity as well as associated host–pathogen dynamics. Yet, experimental evidence linking the mating system to evolved sexual dimorphism in immunity are scarce and the direct effects of mating rate on immunity are not well established. Here, we use transcriptomic analyses, experimental evolution and phylogenetic comparative methods to study the association between the mating system and sexual dimorphism in immunity in seed beetles, where mating causes internal injuries in females. Results We demonstrate that female phenoloxidase (PO) activity, involved in wound healing and defence against parasitic infections, is elevated relative to males. This difference is accompanied by concomitant sex differences in the expression of genes in the prophenoloxidase activating cascade. We document substantial phenotypic plasticity in female PO activity in response to mating and show that experimental evolution under enforced monogamy (resulting in low remating rates and reduced sexual conflict relative to natural polygamy) rapidly decreases female (but not male) PO activity. Moreover, monogamous females had evolved increased tolerance to bacterial infection unrelated to mating, implying that female responses to costly mating may trade off with other aspects of immune defence, an hypothesis which broadly accords with the documented sex differences in gene expression. Finally, female (but not male) PO activity shows correlated evolution with the perceived harmfulness of male genitalia across 12 species of seed beetles, suggesting that sexual conflict has a significant influence on sexual dimorphisms in immunity in this group of insects. Conclusions Our study provides insights into the links between sexual conflict and sexual dimorphism in immunity and suggests that selection pressures moulded by mating interactions can lead to a sex-specific mosaic of immune responses with important implications for host–pathogen dynamics in sexually reproducing organisms.

The nanoanatomical basis of sexual dimorphism in iridescent butterfly colouration

2012 ◽  
Vol 60 (2) ◽  
pp. 101 ◽  
Author(s):  
Thomas E. White ◽  
Joseph Macedonia ◽  
Debra Birch ◽  
Judith Dawes ◽  
Darrell J. Kemp
Keyword(s):  
Sex Differences ◽  
Sexual Dimorphism ◽  
Phenotypic Variation ◽  
Functional Variation ◽  
Present Evidence ◽  
Signal Variation ◽  
Common Basis ◽  
Scale Surface ◽  
Colour Signals

Structurally generated colours are at least as commonplace and varied components of animal signals as pigment colours, yet we know far less about the former, both in terms of the patterns and phenotypic variation and of their underlying correlates and causes. Many butterflies exhibit bright and iridescent colour signals that arise from a characteristic ‘ridge-lamellar’ scale surface nanoarchitecture. Although there are multiple axes of functional variation in these traits, few have been investigated. Here we present evidence that sexual dimorphism in the expression of a sexually homologous ridge-lamellar trait (iridescent ultraviolet) is mediated by sex differences in the density of lamellar-bearing scale ridges. This trait – ridge density – has also been causally related to iridescent signal variation in other coliadines (e.g. C. eurytheme), which suggests that it may offer a common basis to both intra- and intersexual differences in ultraviolet wing reflectance among these butterflies.

Sex differences in white adipose tissue expansion: emerging molecular mechanisms

2021 ◽  
Vol 135 (24) ◽  
pp. 2691-2708
Author(s):  
Simon T. Bond ◽  
Anna C. Calkin ◽  
Brian G. Drew
Keyword(s):  
Sex Differences ◽  
Sexual Dimorphism ◽  
Gene Networks ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Association Studies ◽  
Tissue Expansion ◽  
Economic Systems ◽  
Genomic Association ◽  
Males And Females

Abstract The escalating prevalence of individuals becoming overweight and obese is a rapidly rising global health problem, placing an enormous burden on health and economic systems worldwide. Whilst obesity has well described lifestyle drivers, there is also a significant and poorly understood component that is regulated by genetics. Furthermore, there is clear evidence for sexual dimorphism in obesity, where overall risk, degree, subtype and potential complications arising from obesity all differ between males and females. The molecular mechanisms that dictate these sex differences remain mostly uncharacterised. Many studies have demonstrated that this dimorphism is unable to be solely explained by changes in hormones and their nuclear receptors alone, and instead manifests from coordinated and highly regulated gene networks, both during development and throughout life. As we acquire more knowledge in this area from approaches such as large-scale genomic association studies, the more we appreciate the true complexity and heterogeneity of obesity. Nevertheless, over the past two decades, researchers have made enormous progress in this field, and some consistent and robust mechanisms continue to be established. In this review, we will discuss some of the proposed mechanisms underlying sexual dimorphism in obesity, and discuss some of the key regulators that influence this phenomenon.

scholarly journals Sex-biased immunity is driven by relative differences in reproductive investment

2014 ◽  
Vol 281 (1790) ◽  
pp. 20140333 ◽  
Author(s):  
Crystal M. Vincent ◽  
Darryl T. Gwynne
Keyword(s):  
Immune Response ◽  
Sex Differences ◽  
Immune System ◽  
Sexual Dimorphism ◽  
Parental Investment ◽  
Sex Role ◽  
Reproductive Investment ◽  
Paternal Investment ◽  
Sexual Competition ◽  
Relative Differences

Sex differences in immunity are often observed, with males generally having a weaker immune system than females. However, recent data in a sex-role-reversed species in which females compete to mate with males suggest that sexually competitive females have a weaker immune response. These findings support the hypothesis that sexual dimorphism in immunity has evolved in response to sex-specific fitness returns of investment in traits such as parental investment and longevity, but the scarcity of data in sex-reversed species prevents us from drawing general conclusions. Using an insect species in which males make a large but variable parental investment in their offspring, we use two indicators of immunocompetence to test the hypothesis that sex-biased immunity is determined by differences in parental investment. We found that when the value of paternal investment was experimentally increased, male immune investment became relatively greater than that of females. Thus, in this system, in which the direction of sexual competition is plastic, the direction of sex-biased immunity is also plastic and appears to track relative parental investment.

Skeletal Muscle Wasting: The Estrogen Side of Sexual Dimorphism

2021 ◽  
Author(s):  
Shawna L. McMillin ◽  
Everett C. Minchew ◽  
Dawn A. Lowe ◽  
Espen E. Spangenburg
Keyword(s):  
Sex Differences ◽  
Sexual Dimorphism ◽  
Molecular Mechanisms ◽  
Muscle Wasting ◽  
Physiological Mechanisms ◽  
Skeletal Muscle Wasting ◽  
Muscle Biology ◽  
Experimental Approaches ◽  
The Impact ◽  
Equal Efficacy

The importance of defining sex differences across various biological and physiological mechanisms is more pervasive now than it has been over the last 15-20 years. As the muscle biology field pushes to identify small molecules and interventions to prevent, attenuate or even reverse muscle wasting, we must consider the effect of sex as a biological variable. It should not be assumed that a therapeutic will affect males and females with equal efficacy or equivalent target affinities under conditions where muscle wasting is observed. With that said, it is not surprising to find that we have an unclear or even a poor understanding of the effects of sex or sex hormones on muscle wasting conditions. Although recent investigations are beginning to establish experimental approaches that will allow investigators to assess the impact of sex-specific hormones on muscle wasting, the field still has not established enough published scientific tools that will allow the field to rigorously address critical hypotheses. Thus, the purpose of this review is to assemble a current summary of knowledge in the area of sexual dimorphism driven by estrogens with an effort to provide insights to interested physiologists on necessary considerations when trying to assess models for potential sex differences in cellular and molecular mechanisms of muscle wasting.

scholarly journals CBMT-45. SEX-SPECIFIC METABOLIC ADAPTIONS IN GLIOBLASTOMA

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi42-vi43
Author(s):  
Jasmin Sponagel ◽  
Shanshan Zhang ◽  
Prakash Chinnaiyan ◽  
Joshua Rubin ◽  
Joseph Ippolito
Keyword(s):  
Sex Differences ◽  
Sexual Dimorphism ◽  
Molecular Mechanisms ◽  
Treatment Strategies ◽  
Tca Cycle ◽  
Metabolic Reprogramming ◽  
Mitochondrial Activity ◽  
Male And Female ◽  
Glutamine Deprivation ◽  
Novel Treatment Strategies

Abstract Glioblastoma (GBM) is the most common and aggressive brain tumor in adults. GBM occurs more commonly in males, but female patients survive significantly longer. Understanding the molecular mechanisms that underlie those sex differences could support novel treatment strategies. In this regard, we found that male and female GBM patient samples differ in their metabolite abundance and that male patients exhibit a significantly higher abundance of TCA cycle metabolites. We confirmed those findings in a murine model of GBM, which has previously yielded important insights into sexual dimorphism in GBM. Strikingly, sex differences in TCA cycle flux were entirely driven by glutamine flux, not glucose flux, suggesting a sex-specific role for glutamine in GBM. Metabolic manipulation through glutamine deprivation resulted in a greater growth inhibition in male GBM cells. Glutamine itself can be utilized for anabolic reactions or it can be converted to glutamate by glutaminase. Only male GBM cells were sensitive to pharmacological glutaminase inhibition with BPTES or CB-839, suggesting that male GBM cells are glutamate dependent while female GBM cells are not. Concordantly, we found significantly higher glutaminase levels in male GBM cells. Furthermore, we found that numerous metabolites (including NADH, ATP, and glutathione) involved in cellular processes downstream of glutamate were more abundant in male GBM cells. In contrast, female GBM cells were resistant to low glutamine conditions and glutaminase inhibitors unless glutamine-synthase activity was disrupted, suggesting that glutamine synthesis might play a more prominent role in female GBM. Together, these data indicate that male and female GBM differ in their metabolic adaptions. Male GBM utilize glutamate to fuel the TCA cycle and mitochondrial activity while female GBM synthesize and utilize glutamine itself. This sexual dimorphism in metabolic reprogramming reveals novel sex specific metabolic targets for GBM and underlines the importance of considering sex in metabolic targeting approaches.

Reversed sexual dimorphism in the beak of a finch

Ibis ◽  
2003 ◽  
Vol 145 (2) ◽  
pp. 341-343 ◽  
Author(s):  
Peter R. Grant ◽  
B. Rosemary Grant
Keyword(s):  
Sexual Dimorphism ◽  
Reversed Sexual Dimorphism
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