scholarly journals Desiccation stress acts as cause as well as cost of dispersal in Drosophila melanogaster

2021 ◽  
Author(s):  
Abhishek Mishra ◽  
Sudipta Tung ◽  
V R Shree Sruti ◽  
P M Shreenidhi ◽  
Sutirth Dey
Keyword(s):  
Negative Association ◽  
Desiccation Stress ◽  
Desiccation Resistance ◽  
Reproductive Cost ◽  
Female Dispersal ◽  
Series Of Experiments ◽  
Males And Females ◽  
Dispersal Evolution ◽  
Trait Associations

Environmental stress is one of the important causes of biological dispersal. At the same time, the process of dispersal itself can incur and/or increase susceptibility to stress for the dispersing individuals. Therefore, in principle, stress can serve as both a cause and a cost of dispersal. Desiccation stress is an environmentally relevant stress faced by many organisms, known to shape their population dynamics and distribution. However, the potentially contrasting roles of desiccation stress as a cause and a cost of dispersal have not been investigated. Furthermore, while desiccation stress often affects organisms in a sex-biased manner, it is not known whether the desiccation-dispersal relationship varies between males and females. We studied the role of desiccation stress as a cause and cost of dispersal in a series of experiments using D. melanogaster adults in two-patch dispersal setups. We were interested in knowing whether (a) dispersers are the individuals that are more susceptible to desiccation stress, (b) dispersers pay a cost in terms of reduced resistance to desiccation stress, (c) dispersal evolution alters the desiccation cost of dispersal, and (d) females pay a reproductive cost of dispersal. For this, we modulated the degree of desiccation stress faced by the flies as well as the provision of rest following a dispersal event. Our data showed that desiccation stress served as a significant cause of dispersal in both sexes. Further investigation revealed an increase in both male and female dispersal propensity with increasing desiccation duration. Next, we found a male-biased cost of dispersal in terms of reduced desiccation resistance. This trend was preserved in dispersal-selected and non-selected controls as well, where the desiccation cost of dispersal in females was very low compared to the males. Finally, we found that the females instead paid a significant reproductive cost of dispersal. Our results highlight the complex relationship between desiccation stress and dispersal, whereby desiccation resistance can show both a positive and a negative association with dispersal. Furthermore, the sex differences observed in these trait associations may translate into differences in movement patterns, thereby giving rise to sex-biased dispersal.

scholarly journals Role of Kisspeptin and NKB in Puberty in Nonhuman Primates: Sex Differences

2019 ◽  
Vol 37 (02) ◽  
pp. 047-055 ◽  
Author(s):  
James P. Garcia ◽  
Kim L. Keen ◽  
Stephanie B. Seminara ◽  
Ei Terasawa
Keyword(s):  
Sex Differences ◽  
Nonhuman Primates ◽  
Reproductive Function ◽  
Contributing Factors ◽  
Gnrh Release ◽  
Pubertal Stages ◽  
Series Of Experiments ◽  
Males And Females ◽  
Flexible Mechanisms

AbstractTo understand the roles of kisspeptin and neurokinin B (NKB) in puberty and sex differences in their involvement, we conducted a series of experiments measuring the release of gonadotropin-releasing hormone (GnRH) and kisspeptin in the median eminence of the hypothalamus in male and female monkeys throughout sexual development. Results indicate that kisspeptin-10 and the NKB agonist, senktide, stimulated GnRH release in males and females at the prepubertal and pubertal stages, but females are much more sensitive to kisspeptin signaling than males. Moreover, throughout the progress of puberty, major remodeling of kisspeptin and NKB signaling pathways for the regulation of GnRH release takes place. In females during puberty, reciprocal pathways (i.e., kisspeptin signaling mediated through NKB neurons and NKB signaling mediated through kisspeptin neurons) are established, to provide powerful and flexible mechanisms for GnRH neurosecretory activity necessary for complex female reproductive function in adulthood. By contrast, during puberty in males, reciprocal pathways are consolidated to a simpler kisspeptin-dominant signaling pathway. Nevertheless, in primates, both kisspeptin and NKB signaling are contributing factors for the pubertal increase in GnRH release, rather than initiating puberty.

Gender Diversity in Computing: An Environmental Perspective

10.28945/3248 ◽  
2008 ◽  
Author(s):  
Cecille Marsh
Keyword(s):  
Gender Diversity ◽  
Household Head ◽  
Female Students ◽  
Political Factors ◽  
Female Household Head ◽  
Dominant Female ◽  
Computer Confidence ◽  
Males And Females ◽  
Research Questions

Previous research conducted by the author investigated the socio-political backgrounds of two groups of female students studying computer-related university programmes. They came from distinctly different backgrounds and were enrolled at two institutions with very different legacies. The author found that socio-political factors, in particular the role of a dominant female household head and aggressive governmental affirmative action, had a significant effect on the girls’ levels of confidence and subsequently on their decision to study computer-related courses. Based on this insight, the researcher undertook to look further into gender diversity with respect to self-perceived general computer confidence and self-perceived ability to program a computer. A sample of both female and male Information T echnology students from very similar disadvantaged socio-economic backgrounds was surveyed. The sample of 204 students was drawn from all three years of the National Diploma in Information Technology. The author considered the following research questions: (i) Do males and females studying computer-related courses have differing computer selfefficacy levels? (ii) Do males and females studying computer programming have differing attitudes towards their ability to program? (iii) Do males and females differ in their attitudes towards the programming learning environment?

Selenium Role in Reproduction, Pregnant/Postpartum Women and Neonates: A Current Study

2020 ◽  
Vol 17 (1) ◽  
pp. 28-37
Author(s):  
Tabinda Sattar
Keyword(s):  
Infant Development ◽  
Selenium Deficiency ◽  
Human Reproduction ◽  
Postpartum Women ◽  
Female Reproduction ◽  
Pregnancy And Lactation ◽  
Males And Females ◽  
One Year ◽  
Selenium Supplements

Background: Selenium is a micronutrient, although required in low amounts, its importance in male and female reproduction is well known. Objectives: The core purpose of this study is to evaluate the role of selenium in human reproduction, during pregnancy/ lactation in women and newborns. The review explains side by side the sources of selenium, required amounts of selenium in humans and during pregnancy or lactation. Methods: Selenium deficiency is a major cause of male infertility. Similarly, selenium deficiency, both in pregnant and postpartum women, would greatly affect the health of the newborn baby in all respects. The effect of maternal selenium upon the fetus and the neonates even one year after birth has been explained with some recent examples. Results: The study elaborates the fact that the selenium deficiency in pregnancy and lactation is common due to fetal/infant development, so selenium supplements must be provided in order to overcome these deficiency symptoms. Conclusions: The better reproductive health in humans is possible due to the sufficient amounts of selenium present both in males and females as well.

scholarly journals Residential Mobility and Trust: The Moderating Role of Cognitive Need for Closure

2021 ◽  
Vol 15 ◽  
pp. 183449092097475
Author(s):  
Na Zhao ◽  
Kaiqiang Xu ◽  
Ling Sun
Keyword(s):  
Residential Mobility ◽  
Interpersonal Trust ◽  
Negative Association ◽  
Trust Game ◽  
Trust Building ◽  
Control Group ◽  
Need For Closure ◽  
Stable Group ◽  
Moderating Role

This study examined the link between residential mobility and interpersonal trust building. Study 1 revealed a negative association between residential mobility and trust by measuring personal residential-mobility history. Study 2 demonstrated that participants who were momentarily primed with mobility showed a lower investment than participants in the control group in a trust game. The results of Study 3 showed that need for closure moderated the link between residential mobility and trust-building intention. Specifically, lower need-for-closure people had a significantly lower trust tendency in the mobility group than in the stable group. These findings illuminate the underlying influence of need for closure in the link between residential mobility and trust.

scholarly journals Genetic Studies of mei-P26 Reveal a Link Between the Processes That Control Germ Cell Proliferation in Both Sexes and Those That Control Meiotic Exchange in Drosophila

Genetics ◽  
2000 ◽  
Vol 155 (4) ◽  
pp. 1757-1772 ◽  
Author(s):  
Scott L Page ◽  
Kim S McKim ◽  
Benjamin Deneen ◽  
Tajia L Van Hook ◽  
R Scott Hawley
Keyword(s):  
Meiotic Recombination ◽  
Double Mutant ◽  
P Element ◽  
Genetic Studies ◽  
Germline Differentiation ◽  
Males And Females ◽  
Bag Of Marbles ◽  
Differentiation And Proliferation

Abstract We present the cloning and characterization of mei-P26, a novel P-element-induced exchange-defective female meiotic mutant in Drosophila melanogaster. Meiotic exchange in females homozygous for mei-P261 is reduced in a polar fashion, such that distal chromosomal regions are the most severely affected. Additional alleles generated by duplication of the P element reveal that mei-P26 is also necessary for germline differentiation in both females and males. To further assess the role of mei-P26 in germline differentiation, we tested double mutant combinations of mei-P26 and bag-of-marbles (bam), a gene necessary for the control of germline differentiation and proliferation in both sexes. A null mutation at the bam locus was found to act as a dominant enhancer of mei-P26 in both males and females. Interestingly, meiotic exchange in mei-P261; bamΔ86/+ females is also severely decreased in comparison to mei-P261 homozygotes, indicating that bam affects the meiotic phenotype as well. These data suggest that the pathways controlling germline differentiation and meiotic exchange are related and that factors involved in the mitotic divisions of the germline may regulate meiotic recombination.

Nitric oxide decreases lung liquid production via guanosine 3′,5′-cyclic monophosphate

2001 ◽  
Vol 280 (5) ◽  
pp. L923-L929 ◽  
Author(s):  
James J. Cummings ◽  
Huamei Wang
Keyword(s):  
Nitric Oxide ◽  
Pulmonary Epithelium ◽  
Fetal Sheep ◽  
Cgmp Analog ◽  
Pulmonary Arterial ◽  
Series Of Experiments ◽  
Lung Liquid ◽  
Tracer Dilution ◽  
Induced Changes

We studied the role of cGMP in nitric oxide (NO)-induced changes in lung liquid production ( J v ) in chronically instrumented fetal sheep. Forty-five studies were done in which J v was measured by a tracer dilution technique. Left pulmonary arterial flow (Qlpa) was measured by a Doppler flow probe. There were two series of experiments. In the first, we gave 8-bromo-cGMP, a cGMP analog, by either the pulmonary vascular or intraluminal route; in the second, we used agents to inhibit or enhance endogenous cGMP activity. When infused directly into the pulmonary circulation, 8-bromo-cGMP significantly increased Qlpa but had no effect on J v. Conversely, when instilled into the lung liquid, 8-bromo-cGMP had no effect on Qlpa but significantly reduced J v. Inhibition of guanylate cyclase activity with methylene blue totally blocked, whereas phosphodiesterase inhibition with Zaprinast significantly enhanced, the effect of instilled NO on J v. Thus the reduction in lung liquid caused by NO appears to be mediated by cGMP, perhaps through a direct effect on the pulmonary epithelium.

The Role of Cutter Eccentricity on Surface Finish and Milling Forces

2004 ◽  
Author(s):  
Tony L. Schmitz ◽  
Jeremiah Couey ◽  
Eric Marsh ◽  
Michael F. Tummond
Keyword(s):  
Surface Finish ◽  
Milling Machine ◽  
Time Domain Simulation ◽  
Machined Surface ◽  
Premature Failure ◽  
Series Of Experiments ◽  
Error Motion ◽  
Milling Forces ◽  
Chip Load

In this paper, the role of milling cutter eccentricity, commonly referred to as runout, is explored to determine its effects on surface topography and milling forces. This work is motivated by the observation that commercially-available cutter bodies often exhibit variation in the teeth/insert radial locations as a result of manufacturing issues. Consequently, the chip load on individual cutting teeth varies periodically, which can lead to premature failure of the cutting edges. Additionally, this chip load variation increases the roughness of machined surfaces. This research isolates the effect of runout on cutting forces and the machined surface finish in a series of experiments completed on a precision milling machine with 0.1 μm positioning repeatability and 0.02 μm spindle error motion. The runout is varied in a controlled fashion and results compared between experiment and a comprehensive time-domain simulation.

scholarly journals Correlation of Intracellular Trehalose Concentration with Desiccation Resistance of Soil Escherichia coli Populations

2012 ◽  
Vol 78 (20) ◽  
pp. 7407-7413 ◽  
Author(s):  
Qian Zhang ◽  
Tao Yan
Keyword(s):  
Escherichia Coli ◽  
De Novo ◽  
Potassium Acetate ◽  
Desiccation Stress ◽  
Desiccation Resistance ◽  
Content Type ◽  
Soil Desiccation ◽  
E Coli ◽  
Organic Solute ◽  
Trehalose Synthesis

ABSTRACTNaturalized soilEscherichia colipopulations need to resist common soil desiccation stress in order to inhabit soil environments. In this study, four representative soilE. colistrains and one lab strain, MG1655, were tested for desiccation resistance via die-off experiments in sterile quartz sand under a potassium acetate-induced desiccation condition. The desiccation stress caused significantly lower die-off rates of the four soil strains (0.17 to 0.40 day−1) than that of MG1655 (0.85 day−1). Cellular responses, including extracellular polymeric substance (EPS) production, exogenous glycine betaine (GB) uptake, and intracellular compatible organic solute synthesis, were quantified and compared under the desiccation and hydrated control conditions. GB uptake appeared not to be a specific desiccation response, while EPS production showed considerable variability among theE. colistrains. AllE. colistrains produced more intracellular trehalose, proline, and glutamine under the desiccation condition than the hydrated control, and only the trehalose concentration exhibited a significant correlation with the desiccation-contributed die-off coefficients (Spearman's ρ = −1.0;P= 0.02).De novotrehalose synthesis was further determined for 15E. colistrains from both soil and nonsoil sources to determine its prevalence as a specific desiccation response. MostE. colistrains (14/15) synthesized significantly more trehalose under the desiccation condition, and the soilE. colistrains produced more trehalose (106.5 ± 44.9 μmol/mg of protein [mean ± standard deviation]) than the nonsoil reference strains (32.5 ± 10.5 μmol/mg of protein).

scholarly journals Teacher Discrimination Reduces School Performance of African American Youth: Role of Gender

2018 ◽  
Vol 8 (10) ◽  
pp. 183 ◽  
Author(s):  
Shervin Assari ◽  
Cleopatra Howard Caldwell
Keyword(s):  
African American ◽  
School Performance ◽  
African American Youth ◽  
National Sample ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Grade Point ◽  
Significant Difference ◽  
Males And Females

Background: Gender may alter African Americans’ vulnerability to discrimination. The type of outcomes that follow exposure to discrimination may also be gender-specific. Although teacher discrimination is known to deteriorate school performance, it is yet unknown whether male and female African American youth differ in the effect of teacher discrimination on school performance. Objective: This cross-sectional study explored the moderating role of gender on the effect of teacher discrimination on school performance in a national sample of African American youth. Methods: The National Survey of American Life-Adolescent Supplement (NSAL-A) enrolled a nationally representative sample (n = 810) of 13–17-year-old African American youth. Demographic factors, socioeconomic status, teacher discrimination, and school performance (grade point average, GPA) were measured. Linear multivariable regression models were applied for data analysis. Results: Males and females reported similar levels of perceived teacher discrimination. In the pooled sample, higher teacher discrimination was associated with lower school performance among African American youth (b = −0.35; 95% confidence interval (CI) = −0.49 to −0.22). Gender interacted with perceived teacher discrimination (b = 12; 95% CI = 0.24–2.02), suggesting a significant difference between males and females in the magnitude of the association between perceived teacher discrimination and GPA. In stratified models, perceived teacher discrimination was associated with worse school performance of females (b = −12; 95% CI = −0.03 to −2.78) but not males (b = 0.01; 95% CI = −0.07 to 0.08). Conclusion: In line with previous studies, gender was found to alter the vulnerability of African American youth to perceived discrimination. African American boys and girls may differ in their sensitivity to the effects of teacher discrimination on school performance.

Beaumont's Contribution to Gastric Psychophysiology: A Reappraisal

1988 ◽  
Vol 33 (7) ◽  
pp. 650-653 ◽  
Author(s):  
François M. Mai
Keyword(s):  
Gastric Emptying ◽  
Delayed Gastric Emptying ◽  
Bile Reflux ◽  
Emotional Arousal ◽  
Gastric Fistula ◽  
Physiological Changes ◽  
Digestive Process ◽  
Psychophysiological Research ◽  
Series Of Experiments

William Beaumont's monograph on the physiology of digestion which was first published in 1833, has become a classic in its field. In a series of experiments over a 10 year period on Alexis St. Martin, a 19 year old Canadian voyageur with a traumatic gastric fistula, Beaumont was the first to describe many important aspects of the digestive process. In two of the 238 experiments Beaumont noted gastric physiological changes induced by emotional arousal, these being bile reflux and delayed gastric emptying. Elsewhere in the book, but not in experimental context, Beaumont referred to non-specific changes in coloration and secretion of the mucous membrane induced by emotion. Modern gastric psychophysiological research has shown that emotional arousal increases, and withdrawal decreases, gastric acid secretion. It has also been shown conclusively that emotion can cause a reflux of bile into the stomach and it may delay gastric emptying. Although the main thrust of Beaumont's work was physiological, he must be credited with being the first investigator to draw attention to the role of emotional arousal in the digestive process.

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