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1

No attitude, no standing around: the organization of social and sexual interaction at a gay male private sex party in New York city.  

PubMed

Following the onset of the AIDS epidemic, many jurisdictions have outlawed commercial sex-on-premise venues (bathhouses, adult theaters, sex clubs), greatly changing the culture of public or group sex. Today, in New York City (NYC), private sex parties are the main venues for group sex. Dozens of such events are held on a regular basis in the city, attracting sometimes a few hundred participants. Past research in group sex venues shows that different spaces allow for different kinds of sexual and social interaction. What are the norms of interaction of today's private sex parties? This article answers this question by using data collected ethnographically in one recurring gay male private sex party in NYC. The event was a small organization that brought all its participants together in one space at the same time, thus creating great physical intimacy and leading to convivial socialization and interpersonal bonding. This differs from the model of anonymous and impersonal sex that previous researchers have seen in public and commercial spaces. Private sex parties present risk for the transmission of HIV and other sexually-transmitted infections, but their organization and norms of interaction also present new avenues for prevention. Policy-makers should work to make these places safer rather than outlawing them. PMID:23979786

Meunier, Étienne

2014-05-01

2

The postnatal development of the sex organs in prenatally and early postnatally irradiated male albino rats  

E-print Network

radiosensitivity in the male rat occurs during 19. 5-21. 5 days of intra-uterine life as shown in rats autopsied at 25 days of postnatal life. In a later report, Beaumont (1962) using a 100r prenatal dose states that. in male rats autopsied at 60 days post... though the testes remained atrophied in those animals irradiated at late stages of intra-uterine life. She states, "By 100 days after birth all seminiferous tubules in animals irradiated at 13. 5 and 15. '5 days appeared to be normal. This observation...

Ricks, Robert Clinton

1964-01-01

3

Sex mosaics in a male dimorphic ant Cardiocondyla kagutsuchi  

NASA Astrophysics Data System (ADS)

Gynandromorphy, or the development of organisms with a combination of male and female morphological features, is common in Hymenoptera. The underlying mechanism is likely associated with the sex-determination system, and studying this phenomenon should lead to a deeper understanding of both embryonic development and sex determination. The reproductive capabilities of gynandromorphs (hereafter, sex mosaics) remain unclear. We studied gynandromorphy in the Malaysian ant Cardiocondyla kagutsuchi, which has sex mosaics of queens (gynandromorphs; mosaic of queens and winged male) and workers (ergatandromorphs; mosaic of worker and wingless ergatoid male). These sex mosaics were classified into seven morphological categories. Most individuals had more male than female body areas. Behavioral observations revealed that sex mosaics behave more in accordance with the “sex” of their brain than that of the reproductive organs (gaster). Relative DNA quantities showed that both female and male regions contained haploid and diploid nuclei, irrespective of their phenotypic appearance, indicating that external appearance did not reflect internal tissues. Nearly one third of the adults were sex mosaics and they were not infected with Wolbachia. Our results suggest that the production of sex mosaics in this species does not pose a substantial cost to colonies and that the underlying causes are therefore not strongly selected against.

Yoshizawa, Juri; Mimori, Kohei; Yamauchi, Katsusuke; Tsuchida, Koji

2009-01-01

4

Sex Bias in Traditionally Male Occupational Programs.  

ERIC Educational Resources Information Center

To evaluate potential sources of female sex bias and sex stereotyping within traditionally male occupational programs at the College of DuPage, programs with low female enrollment were selected for study: air conditioning and refrigeration, architectural drafting, auto service, building construction, criminal justice, electronics, fire science,…

Bakshis, Robert; Godshalk, James

5

Effect of housing system, slaughter weight and slaughter strategy on carcass and meat quality, sex organ development and androstenone and skatole levels in Duroc finished entire male pigs.  

PubMed

This study aimed at evaluating the effect of housing system (HS), slaughter weight (SW) and strategy (SS) on carcass a nd meat quality, sexual organ development and boar taint in entire males. Twelve pens of 10 pigs were used (two trials). Half of male pens were allowed visual contact with females (MF) and half with males (MM). Half MM or MF were slaughtered at 105 or 130 kg in trial 1, or penwise or by split marketing in trial 2 at 120 kg. Housing system showed no significant effect on carcass or meat quality. MF presented significantly longer testicles and heavier bulbourethral glands compared to MM. The distribution of androstenone and skatole levels was affected by SW but not by HS or SS, samples with androstenone >1 ?g/g of the different groups falling within the range of 16 to 22%. All correlations between androstenone and sex organs were significant. Housing system and slaughter strategy did not reduce the risk of boar tainted carcasses. PMID:21641121

Fàbrega, E; Gispert, M; Tibau, J; Hortós, M; Oliver, M A; Furnols, M Font I

2011-12-01

6

Male pygmy hippopotamus influence offspring sex ratio  

PubMed Central

Pre-determining fetal sex is against the random and equal opportunity that both conceptus sexes have by nature. Yet, under a wide variety of circumstances, populations shift their birth sex ratio from the expected unity. Here we show, using fluorescence in situ hybridization, that in a population of pygmy hippopotamus (Choeropsis liberiensis) with 42.5% male offspring, males bias the ratio of X- and Y-chromosome-bearing spermatozoa in their ejaculates, resulting in a 0.4337±0.0094 (mean±s.d.) proportion of Y-chromosome-bearing spermatozoa. Three alternative hypotheses for the shifted population sex ratio were compared: female counteract male, female indifferent, or male and female in agreement. We conclude that there appears little or no antagonistic sexual conflict, unexpected by prevailing theories. Our results indicate that males possess a mechanism to adjust the ratio of X- and Y-chromosome-bearing spermatozoa in the ejaculate, thereby substantially expanding currently known male options in sexual conflict. PMID:22426218

Saragusty, Joseph; Hermes, Robert; Hofer, Heribert; Bouts, Tim; Göritz, Frank; Hildebrandt, Thomas B.

2012-01-01

7

Sex Steroid Actions in Male Bone  

PubMed Central

Sex steroids are chief regulators of gender differences in the skeleton, and male gender is one of the strongest protective factors against osteoporotic fractures. This advantage in bone strength relies mainly on greater cortical bone expansion during pubertal peak bone mass acquisition and superior skeletal maintenance during aging. During both these phases, estrogens acting via estrogen receptor-? in osteoblast lineage cells are crucial for male cortical and trabecular bone, as evident from conditional genetic mouse models, epidemiological studies, rare genetic conditions, genome-wide meta-analyses, and recent interventional trials. Genetic mouse models have also demonstrated a direct role for androgens independent of aromatization on trabecular bone via the androgen receptor in osteoblasts and osteocytes, although the target cell for their key effects on periosteal bone formation remains elusive. Low serum estradiol predicts incident fractures, but the highest risk occurs in men with additionally low T and high SHBG. Still, the possible clinical utility of serum sex steroids for fracture prediction is unknown. It is likely that sex steroid actions on male bone metabolism rely also on extraskeletal mechanisms and cross talk with other signaling pathways. We propose that estrogens influence fracture risk in aging men via direct effects on bone, whereas androgens exert an additional antifracture effect mainly via extraskeletal parameters such as muscle mass and propensity to fall. Given the demographic trends of increased longevity and consequent rise of osteoporosis, an increased understanding of how sex steroids influence male bone health remains a high research priority. PMID:25202834

Laurent, Michaël R.; Claessens, Frank; Gielen, Evelien; Lagerquist, Marie K.; Vandenput, Liesbeth; Börjesson, Anna E.; Ohlsson, Claes

2014-01-01

8

Participant Characteristics Sex 4 Male 7 Female  

E-print Network

Participant Characteristics (N=11*) Sex 4 Male 7 Female Age (Mean 67) 2 ( were invited and declined (objected to using a computer) 1 dropped half-way through the study (for Study Meg Wise, PhD,1 Lucille Marchand, MD, 2,3 James F. Cleary, MD 3,4 University of Wisconsin

Wisconsin at Madison, University of

9

[Topography of the organs of the pelvic cavity and macroscopic and histologic findings of the sex organs of a male giant anteater (Myrmecophaga tridactyla) with regard to fertility].  

PubMed

A study was conducted on the reproductive organs of a male Giant Anteater. Discussed is the specific anatomy with its effect on fertility. The ovoid testicles are characterized by an intraabdominal position throughout life. Histologically documented is the active spermiogenesis. The accessory sexual glands consist of a glandula prostatica, glandula vesiculares and glandulae bulbourethrales. The short penis is situated immediately ventral to the anus. The existing anatomic individualities in comparison to other mammalia result in special reproductive aspects and should be taken into consideration for successful breeding. PMID:2025213

Bartmann, C P; Beyer, C; Wissdorf, H

1991-02-01

10

Secondary sex ratios and male lifespan: Damaged or culled cohorts  

E-print Network

reportedly reduce the human secondary sex ratio (i.e. , thepopulation health T he human secondary sex ratio (i.e. , thehumans reportedly shorten gestation and affect males in utero more than females (10). The sex

Catalano, Ralph; Bruckner, Tim

2006-01-01

11

Transgenerational sex determination: the embryonic environment experienced by a male affects offspring sex ratio  

PubMed Central

Conditions experienced during embryonic development can have lasting effects, even carrying across generations. Most evidence for transgenerational effects comes from studies of female mammals, with much less known about egg-laying organisms or paternally-mediated effects. Here we show that offspring sex can be affected by the incubation temperature its father experiences years earlier. We incubated eggs of an Australian lizard with temperature-dependent sex determination under three thermal regimes; some eggs were given an aromatase inhibitor to produce sons at temperatures that usually produce only daughters. Offspring were raised to maturity and freely interbred within field enclosures. After incubating eggs of the subsequent generation and assigning parentage, we found that the developmental temperature experienced by a male significantly influences the sex of his future progeny. This transgenerational effect on sex ratio may reflect an epigenetic influence on paternally-inherited DNA. Clearly, sex determination in reptiles is far more complex than is currently envisaged. PMID:24048344

Warner, Daniel A.; Uller, Tobias; Shine, Richard

2013-01-01

12

Transgenerational sex determination: the embryonic environment experienced by a male affects offspring sex ratio.  

PubMed

Conditions experienced during embryonic development can have lasting effects, even carrying across generations. Most evidence for transgenerational effects comes from studies of female mammals, with much less known about egg-laying organisms or paternally-mediated effects. Here we show that offspring sex can be affected by the incubation temperature its father experiences years earlier. We incubated eggs of an Australian lizard with temperature-dependent sex determination under three thermal regimes; some eggs were given an aromatase inhibitor to produce sons at temperatures that usually produce only daughters. Offspring were raised to maturity and freely interbred within field enclosures. After incubating eggs of the subsequent generation and assigning parentage, we found that the developmental temperature experienced by a male significantly influences the sex of his future progeny. This transgenerational effect on sex ratio may reflect an epigenetic influence on paternally-inherited DNA. Clearly, sex determination in reptiles is far more complex than is currently envisaged. PMID:24048344

Warner, Daniel A; Uller, Tobias; Shine, Richard

2013-01-01

13

More Than a Sex Machine: Accomplishing Masculinity Among Chinese Male Sex Workers in the Hong Kong Sex Industry  

Microsoft Academic Search

Situated in the masculinity and deviance literature, this article examines a “deviant” masculinity, that of the male sex worker, and presents the ways men who engage in sex work cope with the job. Based on in-depth interviews of Chinese male sex workers (n = 18) in the Hong Kong sex industry, I argue that the stigma management techniques these men employ are

Travis S. K. Kong

2009-01-01

14

New pleasures and old dangers: reinventing male sex work.  

PubMed

Understandings of male sex workers (MSWs) shift with technological, conceptual, and social changes. Research has historically constructed MSWs as psychologically unstable, desperate, or destitute victims and their clients as socially deviant perverts. These perceptions, however, are no longer supported by contemporary research and changing societal perceptions of the sex industry, challenging how we understand and describe "escorts." The changing understandings of sexuality and the increasing power of the Internet are both important forces behind recent changes in the structure and organization of MSWs. The growth in the visibility and reach of escorts has created opportunities to form an occupational account of MSWs that better accounts for the dynamic and diverse nature of the MSW experience in the early 21st century. Recent changes in the structure and organization of male sex work have provided visibility to the increasingly diverse geographical distribution of MSW, the commodification of race and racialized desire, new populations of heterosexual men and women as clients, and the successful dissemination of safer sexual messages to MSWs through online channels. This article provides a broad overview of the literature on MSWs, concentrating its focus on studies that have emerged over the past 20 years and identifying areas for future research. PMID:23480072

Minichiello, Victor; Scott, John; Callander, Denton

2013-01-01

15

Sex Genotype and Sex Phenotype Contribute to Growth Differences Between Male and Female Channel Catfish  

Technology Transfer Automated Retrieval System (TEKTRAN)

Channel catfish have an XX:XY genotypic system of sex determination, and until the present study, the influence of sex genotype on growth could not be distinguished from sex phenotype. Genotypic male fish (XY) were produced by mating normal (XX) female fish with YY male fish. A subsample from eac...

16

Gender Imbalance: The Male\\/Female Sex Ratio Determination  

Microsoft Academic Search

Synopsis  The aim of this paper is to develop a rational choice model for male\\/female sex ratio determination. The equilibrium sex ratio at birth is determined by the preference for sons and birth rates. The conventional theory predicts that low birth rate will increase the disparity between male and female births. However, our model predicts that low birth rate will decrease

Yong J. Yoon

2006-01-01

17

Sex or Food? Appetetive Learning of Sex Odors in a Male Moth  

Microsoft Academic Search

Moths learn to associate a flower odor with a food reward after a few learning trials. Can a hungry, male moth learn to associate\\u000a a sex attractant with food instead of with sex? We provided a hungry male with odors of single female sex pheromone components,\\u000a of the full sex pheromone blend or of a flower odor component as cues

Elke Hartlieb; Bill S. Hansson; Peter Anderson

1999-01-01

18

Double-strand break repair on sex chromosomes: challenges during male meiotic prophase.  

PubMed

During meiotic prophase, DNA double-strand break (DSB) repair-mediated homologous recombination (HR) occurs for exchange of genetic information between homologous chromosomes. Unlike autosomes or female sex chromosomes, human male sex chromosomes X and Y share little homology. Although DSBs are generated throughout male sex chromosomes, homologous recombination does not occur for most regions and DSB repair process is significantly prolonged. As a result, male sex chromosomes are coated with many DNA damage response proteins and form a unique chromatin structure known as the XY body. Interestingly, associated with the prolonged DSB repair, transcription is repressed in the XY body but not in autosomes, a phenomenon known as meiotic sex chromosome inactivation (MSCI), which is critical for male meiosis. Here using mice as model organisms, we briefly summarize recent progress on DSB repair in meiotic prophase and focus on the mechanism and function of DNA damage response in the XY body. PMID:25565522

Lu, Lin-Yu; Yu, Xiaochun

2015-02-16

19

Molecular Mechanisms in Male Sex Determination  

E-print Network

formed, hormones direct the process of sex differentiationsex differentiation is an active process requiring testes derived hormones,Sex differentiation refers to the downstream effects that are modulated by hormones

Arboleda, Valerie Anne

2012-01-01

20

OFFSPRING SEX RATIO IN DEER MALE REPRODUCTIVE PHYSIOLOGY AND OFFSPRING SEX RATIO IN ODOCOILEUS VIRGINIANUS.  

Technology Transfer Automated Retrieval System (TEKTRAN)

The primary sex ratio of the family Cervidae may vary at conception and/or birth from an expected 50:50 (males:females). Fertilization by X- or Y- chromosome-bearing sperm (referred to simply as X- and Y- sperm) ultimately controls the sex of offspring; however, alteration of the fetal sex ratio co...

21

Sex or Food? Appetetive Learning of Sex Odors in a Male Moth  

NASA Astrophysics Data System (ADS)

Moths learn to associate a flower odor with a food reward after a few learning trials. Can a hungry, male moth learn to associate a sex attractant with food instead of with sex? We provided a hungry male with odors of single female sex pheromone components, of the full sex pheromone blend or of a flower odor component as cues in an appetitive learning assay. The male learned the single pheromone components just as well as the flower odor. Learning was, however, severely impaired when the full sex pheromone blend was used as conditioning stimulus. The "hard-wiring" between pheromone odor and sex thus seems to be restricted to those circumstances when the male moth experiences the full blend.

Hartlieb, Elke; Hansson, Bill S.; Anderson, Peter

22

Male mutation rates and the cost of sex for females  

NASA Astrophysics Data System (ADS)

ALTHOUGH we do not know why sex evolved, the twofold cost of meiosis for females provides a standard against which postulated benefits of sex can be evaluated1. The most reliable benefit is sex's ability to reduce the impact of deleterious mutations2,3. But deleterious mutations may themselves generate a large and previously overlooked female-specific cost of sex. DNA sequence comparisons have confirmed Haldane's suggestion that most mutations arise in the male germ line4,5; recent estimates of ?, the ratio of male to female mutation rates, are ten, six and two in humans, primates and rodents, respectively6-8. Consequently, male gametes may give progeny more mutations than the associated sexual recombination eliminates. Here I describe computer simulations showing that the cost of male mutations can easily exceed the benefits of recombination, causing females to produce fitter progeny by parthenogenesis than by mating. The persistence of sexual reproduction by females thus becomes even more problematic.

Redfield, Rosemary J.

1994-05-01

23

Sex-typed role in male adolescent sexual abuse survivors  

Microsoft Academic Search

Confusion and conflicts regarding sexual identity have been identified by clinicians as sequelae of sexual abuse in male adolescents. The empirical evidence supporting this assertion is limited, however. The purpose of this study was to examine the relationship between sexual abuse of male adolescents and their sexual self-concept in comparison to other clinical and nonclinical adolescent populations. The Bem Sex-Role

Melissa Frey Richardson; William Meredith; Douglas A. Abbot

1993-01-01

24

The evolution of sex chromosomes in organisms with separate haploid sexes.  

PubMed

The evolution of dimorphic sex chromosomes is driven largely by the evolution of reduced recombination and the subsequent accumulation of deleterious mutations. Although these processes are increasingly well understood in diploid organisms, the evolution of dimorphic sex chromosomes in haploid organisms (U/V) has been virtually unstudied theoretically. We analyze a model to investigate the evolution of linkage between fitness loci and the sex-determining region in U/V species. In a second step, we test how prone nonrecombining regions are to degeneration due to accumulation of deleterious mutations. Our modeling predicts that the decay of recombination on the sex chromosomes and the addition of strata via fusions will be just as much a part of the evolution of haploid sex chromosomes as in diploid sex chromosome systems. Reduced recombination is broadly favored, as long as there is some fitness difference between haploid males and females. The degeneration of the sex-determining region due to the accumulation of deleterious mutations is expected to be slower in haploid organisms because of the absence of masking. Nevertheless, balancing selection often drives greater differentiation between the U/V sex chromosomes than in X/Y and Z/W systems. We summarize empirical evidence for haploid sex chromosome evolution and discuss our predictions in light of these findings. PMID:25582562

Immler, Simone; Otto, Sarah Perin

2015-03-01

25

Tactics for male reproductive success in plants: contrasting insights of sex allocation theory and pollen presentation theory  

Microsoft Academic Search

Synopsis The basic tenet of sex allocation theory is that an organism's reproductive success, through either male or female function, can be represented as a sex-specific, monotonic, increasing function ofthe organism'sinvestment ofresources inthat function. The shapes of these curves determine what patterns of resource allocation can be evolutionarily stable. Although SA theory has stimulated creative thinking about plant sexual tactics,

James D. Thomson

2006-01-01

26

Male-to-Female Sex Reversal in Mice Lacking Fibroblast Growth Factor 9  

Microsoft Academic Search

Fgfs direct embryogenesis of several organs, including the lung, limb, and anterior pituitary. Here we report male-to-female sex reversal in mice lacking Fibroblast growth factor 9 (Fgf9), demonstrating a novel role for FGF signaling in testicular embryogenesis. Fgf9?\\/? mice also exhibit lung hypoplasia and die at birth. Reproductive system phenotypes range from testicular hypoplasia to complete sex reversal, with most

Jennifer S. Colvin; Rebecca P. Green; Jennifer Schmahl; Blanche Capel; David M. Ornitz

2001-01-01

27

Ambient temperature predicts sex ratios and male longevity  

PubMed Central

The theory that natural selection has conserved mechanisms by which women subjected to environmental stressors abort frail male fetuses implies that climate change may affect sex ratio at birth and male longevity. Using time series methods, we find that cold ambient temperatures during gestation predict lower secondary sex ratios and longer life span of males in annual birth cohorts composed of Danes, Finns, Norwegians, and Swedes born between 1878 (earliest year with complete life tables) and 1914 (last birth cohort for which male life span can be estimated). We conclude that ambient temperature affects the characteristics of human populations by influencing who survives gestation, a heretofore unrecognized effect of climate on humanity. PMID:18250336

Catalano, Ralph; Bruckner, Tim; Smith, Kirk R.

2008-01-01

28

The ontogeny of sex appeal in Drosophila melanogaster males  

Microsoft Academic Search

Drosophila melanogaster males are sexually attractive when they are young, but they elicit very little courtship when they are 2–3 days old. We have shown that males from a Canton-S stock start to lose their sex appeal between 3 and 4 h after they eclose from their pupal cases because they have begun to synthesizecis-vaccenyl acetate, an inhibitory pheromone, by

Paul G. Curcillo; Laurie Tompkins

1987-01-01

29

Male Reproductive System  

MedlinePLUS

... your son's reproductive health. Continue About the Male Reproductive System Most species have two sexes: male and female. ... has been removed. Back Continue What the Male Reproductive System Does The male sex organs work together to ...

30

Latino Cross-Cultural Same Sex Male Relationships  

Microsoft Academic Search

Utilizing six different gay couples this article illustrates salient issues relevant to Latino cross-cultural same-sex male relationships. It emphasizes issues of both similarities and differences in terms of ethnicity, race, class, language, and other domains of influence. It conveys the potential danger of conceptualizing Latinos as members of a same race group, or as a homogeneous group. Furthermore, it identifies

Andres Nazario

2003-01-01

31

Economic Transition, Male Competition, and Sex Differences in Mortality  

Microsoft Academic Search

Sex differences in mortality rates stem from a complex set of genetic, physiological, psychological, and social causes whose interconnections are best understood in an integrative evolutionary framework. We predicted that the transition from centrally planned to market economies in Eastern Europe inflated the discrepancy between male and female mortality rates, because economic uncertainty and increasing variation and skew in social

Daniel J. Kruger; Randolph M. Nesse

2007-01-01

32

Chemosterilization of male sea lampreys, (Petromyzon marinus), does not affect sex pheromone release  

USGS Publications Warehouse

Release of males sterilized by injection with bisazir is an important experimental technique in management of sea lamprey (Petromyzon marinus), an invasive, nuisance species in the Laurentian Great Lakes. Sea lampreys are semelparous and sterilization can theoretically eliminate a male's reproductive capacity and, if the ability to obtain mates is not affected, waste the sex products of females spawning with him. It has been demonstrated that spermiating males release a sex pheromone that attracts ovulating females. We demonstrated that sterilized, spermiating males also released the pheromone and attracted ovulating females. In a two-choice maze, ovulating females increased searching behavior and spent more time in the side of the maze containing chemical stimuli from sterilized, spermiating males. This attraction response was also observed in spawning stream experiments. Also, electro-olfactograms showed that female olfactory organs were equally sensitive to chemical stimuli from sterilized and nonsterilized, spermiating males. Finally, fast atom bombardment mass spectrometry showed that extracts from water conditioned with sterilized and nonsterilized, spermiating males contained the same pheromonal molecule at similar levels. We concluded that injection of bisazir did not affect the efficacy of sex pheromone in sterilized males.

Siefkes, Michael J.; Bergstedt, Roger A.; Twohey, Michael B.; Li, Weiming

2003-01-01

33

Regulation of male sex determination: genital ridge formation and Sry activation in mice.  

PubMed

Sex determination is essential for the sexual reproduction to generate the next generation by the formation of functional male or female gametes. In mammals, primary sex determination is commenced by the presence or absence of the Y chromosome, which controls the fate of the gonadal primordium. The somatic precursor of gonads, the genital ridge is formed at the mid-gestation stage and gives rise to one of two organs, a testis or an ovary. The fate of the genital ridge, which is governed by the differentiation of somatic cells into Sertoli cells in the testes or granulosa cells in the ovaries, further determines the sex of an individual and their germ cells. Mutation studies in human patients with disorders of sex development and mouse models have revealed factors that are involved in mammalian sex determination. In most of mammals, a single genetic trigger, the Y-linked gene Sry (sex determination region on Y chromosome), regulates testicular differentiation. Despite identification of Sry in 1990, precise mechanisms underlying the sex determination of bipotential genital ridges are still largely unknown. Here, we review the recent progress that has provided new insights into the mechanisms underlying genital ridge formation as well as the regulation of Sry expression and its functions in male sex determination of mice. PMID:25139092

Tanaka, Satomi S; Nishinakamura, Ryuichi

2014-12-01

34

HIV prevention interventions for young male commercial sex workers.  

PubMed

The sex industry, where men sell sexual services to other men or women, has grown in recent years. These men who offer sexual services are particularly vulnerable to HIV infection due to such factors as: frequency of risky sexual practices, number of sex partners, drug-taking, prevalence of sexually-transmitted infections (STI) and their specific situation of social exclusion which may hinder access to health services. These multi-faceted realities faced by sex workers explain the burgeoning interest in new avenues of scientific research. There are too few preventive programs however aimed at this population group and the studies that evaluate their effectiveness are fewer still. In this article we survey more recent studies on the difficulties of implementing programs for HIV prevention in male sex workers (MSW), as well as the studies that have gauged the impact of preventive programs in this group. PMID:24366476

Ballester-Arnal, R; Gil-Llario, M D; Salmeron-Sánchez, P; Giménez-García, C

2014-03-01

35

A sex-specific transcription factor controls male identity in a simultaneous hermaphrodite  

PubMed Central

Evolutionary transitions between hermaphroditic and dioecious reproductive states are found in many groups of animals. To understand such transitions, it is important to characterize diverse modes of sex determination utilized by metazoans. Currently, little is known about how simultaneous hermaphrodites specify and maintain male and female organs in a single individual. Here we show that a sex-specific gene, Smed-dmd-1 encoding a predicted doublesex/male-abnormal-3 (DM) domain transcription factor, is required for specification of male germ cells in a simultaneous hermaphrodite, the planarian Schmidtea mediterranea. dmd-1 has a male-specific role in the maintenance and regeneration of the testes and male accessory reproductive organs. In addition, a homologue of dmd-1 exhibits male-specific expression in Schistosoma mansoni, a derived, dioecious flatworm. These results demonstrate conservation of the role of DM domain genes in sexual development in lophotrochozoans and suggest one means by which modulation of sex-specific pathways can drive the transition from hermaphroditism to dioecy. PMID:23652002

Chong, Tracy; Collins, James J.; Brubacher, John L.; Zarkower, David; Newmark, Phillip A.

2013-01-01

36

Motivational Influences on the Safer Sex Behavior of Agency-based Male Sex Workers  

Microsoft Academic Search

Although indoor male sex workers (MSWs) have been found to engage in lower rates of HIV risk behavior with clients than street-based\\u000a MSWs, few studies have examined the motivations behind such practices. We interviewed 30 MSWs working for the same escort\\u000a agency regarding their safer sex practices with clients and their reasons for these. As in other research, MSWs reported

Michael D. Smith; David W. Seal

2008-01-01

37

Male-biased reproduction and sex-ratio adjustment in muskrats  

Microsoft Academic Search

Sex ratios of a population and of litters were sampled in muskrats in Ontario, Canada. Sex ratios of litters sampled from nests were male biased (54% male). Until weaning, no differential costs of producing and rearing male and female young were identified that could account for this greater production of males. Following weaning, however, male-biased dispersal of juveniles from their

M. J. Caley; S. Boutin; R. A. Moses

1988-01-01

38

Multiple risks among male and transgender sex workers in Pakistan.  

PubMed

Using data from a qualitative study and a subsequent quantitative survey among 918 male and transgender sex workers (MTSW), we explore the context of multiple risks they face. We show that over one-fifth of MTSW have sex with IDU clients. Combined with high levels of risk behavior and very low levels of risk reduction and knowledge, the extent of sexual networking with men who inject drugs contributes further to the sex workers' health risks. Our findings suggest that isolated interventions with single-risk groups are unlikely to be sufficient to control the spread of the epidemic in Pakistan. We highlight the need for integrated approaches to risk reduction programs among MTSW and IDUs. PMID:19856740

Collumbien, Martine; Chow, Jaime; Qureshi, Ayaz Ahmed; Rabbani, Aliya; Hawkes, Sarah

2008-01-01

39

Internest sex-ratio variation and male brood survival in the ant Pheidole pallidula  

Microsoft Academic Search

Sex allocation in social insects has become a general model in tests of inclusive fitness theory, sex-ratio theory, and parent- offspring conflict. Several studies have shown that colony sex ratios are often bimodally distributed, with some colonies producing mainly females and others mainly males. Sex specialization may result from workers assessing their relatedness to male brood versus female brood, relative

Laurent Keller; Serge Aron; Luc Passerab

1996-01-01

40

The scent of inbreeding: a male sex pheromone betrays inbred males  

PubMed Central

Inbreeding depression results from mating among genetically related individuals and impairs reproductive success. The decrease in male mating success is usually attributed to an impact on multiple fitness-related traits that reduce the general condition of inbred males. Here, we find that the production of the male sex pheromone is reduced significantly by inbreeding in the butterfly Bicyclus anynana. Other traits indicative of the general condition, including flight performance, are also negatively affected in male butterflies by inbreeding. Yet, we unambiguously show that only the production of male pheromones affects mating success. Thus, this pheromone signal informs females about the inbreeding status of their mating partners. We also identify the specific chemical component (hexadecanal) probably responsible for the decrease in male mating success. Our results advocate giving increased attention to olfactory communication as a major causal factor of mate-choice decisions and sexual selection. PMID:23466986

van Bergen, Erik; Brakefield, Paul M.; Heuskin, Stéphanie; Zwaan, Bas J.; Nieberding, Caroline M.

2013-01-01

41

Androgens stimulate sex change in protogynous grouper, Epinephelus coioides: spawning performance in sex-changed males.  

PubMed

We examined the efficacy of androgens (1.0 mg/kg body mass), testosterone (T), 11-ketotestosterone (11-KT), 17alpha-methyltestosterone (MT), testosterone propionate (TP) or androgen mixture (T, MT and TP in an equal ratio), for induction of sex change in protogynous orange-spotted grouper, Epinephelus coioides. The spawning performance in sex-changed males was also investigated. MT and androgen mixture at a dose of 1.0 mg/kg BW induced a sex transition and completion of spermatogenesis up to the functional male phase. The androgen mixture was most effective. Significantly, higher plasma T levels were found in MT and androgen mixture groups compared to control and other androgen implantation (T, TP or 11-KT) groups. We found that plasma levels of estradiol-17beta (E2) or 11-KT were not different among treated groups. Sex-changed males could successfully fertilize mature eggs. Fertilization and hatching rates were of 23.5-70.4% and 8.4-44.6%, respectively. The data demonstrated that induction of sex change by exogenous androgens in groups could apply to the aquaculture field for seed production. PMID:12927912

Yeh, Shinn-Lih; Kuo, Ching-Ming; Ting, Yun-Yuan; Chang, Ching-Fong

2003-07-01

42

Male sex workers: practices, contexts, and vulnerabilities for HIV acquisition and transmission.  

PubMed

Male sex workers who sell or exchange sex for money or goods encompass a very diverse population across and within countries worldwide. Information characterising their practices, contexts where they live, and their needs is limited, because these individuals are generally included as a subset of larger studies focused on gay men and other men who have sex with men (MSM) or even female sex workers. Male sex workers, irrespective of their sexual orientation, mostly offer sex to men and rarely identify as sex workers, using local or international terms instead. Growing evidence indicates a sustained or increasing burden of HIV among some male sex workers within the context of the slowing global HIV pandemic. Several synergistic facilitators could be potentiating HIV acquisition and transmission among male sex workers, including biological, behavioural, and structural determinants. Criminalisation and intersectional stigmas of same-sex practices, commercial sex, and HIV all augment risk for HIV and sexually transmitted infections among male sex workers and reduce the likelihood of these people accessing essential services. These contexts, taken together with complex sexual networks among male sex workers, define this group as a key population underserved by current HIV prevention, treatment, and care services. Dedicated efforts are needed to make those services available for the sake of both public health and human rights. Evidence-based and human rights-affirming services dedicated specifically to male sex workers are needed to improve health outcomes for these men and the people within their sexual networks. PMID:25059939

Baral, Stefan David; Friedman, M Reuel; Geibel, Scott; Rebe, Kevin; Bozhinov, Borche; Diouf, Daouda; Sabin, Keith; Holland, Claire E; Chan, Roy; Cáceres, Carlos F

2015-01-17

43

Extremely female-biased sex ratio and lethal male--male combat in a parasitoid wasp, Melittobia australica (Eulophidae)  

Microsoft Academic Search

Melittobia australica (Hymenoptera: Eulophidae) is a gregarious ectoparasitoid of the prepupae and pupae of solitary wasps and bees. The males never disperse from their natal patch, and mating takes place only on the host from which they emerged. We measured the offspring sex ratio of M. australica with differing foundress numbers and examined combat between emerged males. The offspring sex

Jun Abe; Yoshitaka Kamimura; Natsuko Kondo; Masakazu Shimadaa

2003-01-01

44

A qualitative study on commercial sex behaviors among male clients in Sichuan Province, China  

Microsoft Academic Search

Males who seek commercial sex have been identified as an important “bridging population” in the transmission of HIV. There is little information on the HIV-related risk perceptions and behaviors among commercial sex male clients (CSMCs) in China. This study reports qualitative findings from six focus groups and 41 in-depth interviews with CSMCs in Sichuan Province, China. Commercial sex visits were

Cui Yang; Carl A. Latkin; Peng Liu; Kenrad E. Nelson; Cunlin Wang; Rongsheng Luan

2010-01-01

45

Sex steroid levels in XY males and sex-reversed XX males, of rainbow trout (Oncorhynchus mykiss), during the reproductive cycle.  

PubMed

In this study, the annual cycle of the gonadal steroids testosterone (T), 11-ketotestosterone (11-KT), 17?-oestradiol (E2) and 17?, 20?-dihydroxy-4-pregnen-3-one (DHP) was determined using radioimmunoassay and then compared, for XY males (n=35) and sex-reversed XX males (n=27) rainbow trout, to establish possible endocrinology differences. Both in XY males and sex-reversed XX males, significant correlation was shown between body weight and T (r=0.5046 and 0.34078, respectively; p<0.0001) or KT (r=0.52494 and 0.43545, respectively; p<0.0001) concentrations. Plasma androgen levels in XY and sex-reversed XX males were similar and showed an intense seasonal variation. The highest levels for T and 11-KT were detected from December to April with a peak in January (51.67 ± 5.11 and 61.95 ± 4.25 ng/ml, for XY males and 57.1 ± 5.82 and 59.27 ± 4.84 ng/ml, respectively, for XX males). In addition, there was a positive correlation (p<0.0001) between T and 11-KT levels for XY males (r=0.7533) and sex-reversed XX males (r=0.6019). Concentrations of DHP in XY males also showed seasonal variation with a peak in February (25.18 ± 12.99 ng/ml). However, DHP levels in sex-reversed XX males were undetectable (<0.1 ng/ml) over the year. Levels of E2 were undetectable through the year in both groups of trout. In conclusion, the androgenic and oestrogenic profiles of sex-reversed XX males were similar to those observed in XY males. The only difference in the annual gonadal steroid cycle between XY and sex-reversed XX males was in the DHP profile. PMID:19663812

Espinosa, E; Josa, A; Gil, L; González, N

2011-02-01

46

Sex, eyes, and vision: male/female distinctions in ophthalmic disorders.  

PubMed

There is growing recognition: (1) that sex (male and female) and sex hormones (androgens and estrogens) are important for physiologic functions outside those pertaining expressly to reproduction, and (2) that both classes of sex hormones are active in both sexes, and moreover are produced locally in non-gonadal tissues throughout the body. The visual system, in addition to being of tremendous inherent importance, is unique in a very distinctive way; it possesses an organ - the eye - having a window allowing its interior to be examined with exquisite precision and control in both laboratory and clinical settings. Plus, many diseases manifest in the eye or are exclusive to the eye. This special issue of Current Eye Research contains 12 review articles, each addressing a different topical area important for Sex, Eyes, and Vision: Male/Female Distinctions in Ophthalmic Disorders. Of course, the distinctions between topical areas are blurred, and the overlap between the various lines of knowledge and investigation likewise is substantial. Eye diseases can be both neurodegenerative and involve altered blood flow, for instance. In fact, the thematic overlap is greater yet, in that the articles for this special issue address matters of interest to clinicians and scientists who may identify more with women's health or sex & gender fields than with eye & vision fields. Nevertheless, because this special issue needs a home, the following 12 topical areas each have here their own dedicated review: age-related maculopathy, central nervous system function and cognition & perception, diabetic retinopathy, dry eye, glaucoma, inherited diseases, lens and cataract, neuro-ophthalmology, ocular blood flow, ocular inflammatory disorders, optical coherence tomography, and sex/gender eye care disparities. This overview article itself raises additional points expressly concerning: (1) the estrogen therapy timing hypothesis, and (2) breast cancer treatment with aromatase inhibitors. PMID:25329177

Eisner, Alvin

2015-02-01

47

Offspring sex ratio is unrelated to male attractiveness in dark-eyed juncos ( Junco hyemalis )  

Microsoft Academic Search

Sex allocation theory predicts that parents should bias investment toward the offspring sex that confers higher relative fitness on the parents. When variance in reproductive success is higher in males than females, and some males are more attractive to females than others, thereby achieving higher reproductive success, female parents mated to attractive males are expected to bias reproductive allocation toward

Jennifer L. Grindstaff; Alex C. Buerkle; Joseph M. Casto; Val Nolan Jr; Ellen D. Ketterson

2001-01-01

48

ORIGINAL PAPER Do sex-changing male snails use mate choice to get a jump  

E-print Network

ORIGINAL PAPER Do sex-changing male snails use mate choice to get a jump on their ``size advantage, it is a common and obvious trait for male choice; size preference has been observed in species from fish (Ptacek may gain a ``size advantage'' from that sex change; that is, as males become larger, they become

49

No Need to Discriminate? Reproductive Diploid Males in a Parasitoid with Complementary Sex Determination  

Microsoft Academic Search

Diploid males in hymenopterans are generally either inviable or sterile, thus imposing a severe genetic load on populations. In species with the widespread single locus complementary sex determination (sl-CSD), sex depends on the genotype at one single locus with multiple alleles. Haploid (hemizygous) individuals are always males. Diploid individuals develop into females when heterozygous and into males when homozygous at

Jan Elias; Dominique Mazzi; Silvia Dorn; Trine Bilde

2009-01-01

50

A Psychosocial Study of Male-to-Female Transgendered and Male Hustler Sex Workers in São Paulo, Brazil  

Microsoft Academic Search

This study examined sociodemographic variables, personality characteristics, and alcohol and drug misuse among male sex workers\\u000a in the city of Santo André, São Paulo, Brazil. A total of 45 male-to-female transgender sex workers and 41 male hustlers were\\u000a evaluated in face-to-face interviews at their place of work from 2008 to 2010. A “snowball” sampling procedure was used to\\u000a access this

Fernanda Cestaro Prado Cortez; Douglas Pieter Boer; Danilo Antonio Baltieri

51

When is a male not a male? Sex recognition and choice in two sex-changing species  

Microsoft Academic Search

For dioecious species, choosing a mate of the same sex can have reproductive costs. For sex-changing animals, however, a lack\\u000a of sex recognition may not carry a reproductive cost, as pairs that were initially same-sex can become opposite-sex pairs\\u000a as one partner changes sex. The strength of sex discrimination in sex changers, then, should depend on the duration of mating

Olivia V. Ambrogio; Jan A. Pechenik

2008-01-01

52

Female-to-male sex reversal in mice caused by transgenic overexpression of Dmrt1.  

PubMed

Genes related to Dmrt1, which encodes a DNA-binding DM domain transcription factor, act as triggers for primary sex determination in a broad range of metazoan species. However, this role is fulfilled in mammals by Sry, a newly evolved gene on the Y chromosome, such that Dmrt1 has become dispensable for primary sex determination and instead maintains Sertoli cell phenotype in postnatal testes. Here, we report that enforced expression of Dmrt1 in XX mouse fetal gonads using a Wt1-BAC transgene system is sufficient to drive testicular differentiation and male secondary sex development. XX transgenic fetal gonads showed typical testicular size and vasculature. Key ovarian markers, including Wnt4 and Foxl2, were repressed. Sertoli cells expressing the hallmark testis-determining gene Sox9 were formed, although they did not assemble into normal testis cords. Other bipotential lineages differentiated into testicular cell types, including steroidogenic fetal Leydig cells and non-meiotic germ cells. As a consequence, male internal and external reproductive organs developed postnatally, with an absence of female reproductive tissues. These results reveal that Dmrt1 has retained its ability to act as the primary testis-determining trigger in mammals, even though this function is no longer normally required. Thus, Dmrt1 provides a common thread in the evolution of sex determination mechanisms in metazoans. PMID:25725066

Zhao, Liang; Svingen, Terje; Ng, Ee Ting; Koopman, Peter

2015-03-15

53

Induction of female Sex-lethal RNA splicing in male germ cells: implications for Drosophila germline sex determination.  

PubMed

With a focus on Sex-lethal (Sxl), the master regulator of Drosophila somatic sex determination, we compare the sex determination mechanism that operates in the germline with that in the soma. In both cell types, Sxl is functional in females (2X2A) and nonfunctional in males (1X2A). Somatic cell sex is determined initially by a dose effect of X:A numerator genes on Sxl transcription. Once initiated, the active state of SXL is maintained by a positive autoregulatory feedback loop in which Sxl protein insures its continued synthesis by binding to Sxl pre-mRNA and thereby imposing the productive (female) splicing mode. The gene splicing-necessary factor (snf), which encodes a component of U1 and U2 snRNPs, participates in this RNA splicing control. Here we show that an increase in the dose of snf+ can trigger the female Sxl RNA splicing mode in male germ cells and can feminize triploid intersex (2X3A) germ cells. These snf+ dose effects are as dramatic as those of X:A numerator genes on Sxl in the soma and qualify snf as a numerator element of the X:A signal for Sxl in the germline. We also show that female-specific regulation of Sxl in the germline involves a positive autoregulatory feedback loop on RNA splicing, as it does in the soma. Neither a phenotypically female gonadal soma nor a female dose of X chromosomes in the germline is essential for the operation of this feedback loop, although a female X-chromosome dose in the germline may facilitate it. Engagement of the Sxl splicing feedback loop in somatic cells invariably imposes female development. In contrast, engagement of the Sxl feedback loop in male germ cells does not invariably disrupt spermatogenesis; nevertheless, it is premature to conclude that Sxl is not a switch gene in germ cells for at least some sex-specific aspects of their differentiation. Ironically, the testis may be an excellent organ in which to study the interactions among regulatory genes such as Sxl, snf, ovo and otu which control female-specific processes in the ovary. PMID:9362474

Hager, J H; Cline, T W

1997-12-01

54

Both male and female novel traits promote the correlated evolution of genitalia between the sexes in an arthropod.  

PubMed

The correlated evolution of genitalia between sexes has been demonstrated in many taxa. However, it remains unclear whether female rather than male genitalia can play a key role in the correlated evolution of male and female genitalia. We conducted an extensive cross-population analysis of the divergence patterns of genital structures, weights of whole genital organs, and the bodies of both sexes, and male genital length in a group of xystodesmid millipedes showing diverse genital morphologies. We demonstrate that the correlated evolution of male and female genitalia toward exaggerated states has occurred in the millipedes, which have evolved novel traits in both males (forceps-like gonopods) and females (retractable bellows). Enlargement and elongation of forceps-like gonopods may be advantageous in sperm competition, whereas enlargement and elongation of the bellows may facilitate acceptance/rejection of insemination for ensuring the female's fitness. These male and female genital parts have affected the correlated evolution in the opposite sex, resulting in diversification and exaggeration of genital morphology. Our study suggests that evolutionary novel traits in not only males but also in females could play an important role in the correlated evolution of genitalia between the sexes. PMID:24116383

Tanabe, Tsutomu; Sota, Teiji

2014-02-01

55

5. Hidden Patterns of Male Sex Hormones and Behaviour Vary with Life History  

Microsoft Academic Search

Androgens regulate sperm production, the expression of secondary sex characters and behavior in males and also vice versa, androgens are modulated by the male's interactions with his social environment. In search for a regular internal \\

Katharina HIRSCHENHAUSER; Didone FRIGERIO

56

Cuticular lipids and odors induce sex-specific behaviors in the male cricket Gryllus bimaculatus  

Microsoft Academic Search

Male crickets display sex-specific (e.g., mating and agonistic) behaviors towards conspecific individuals. One of the key signals for these behaviors is the chemical substance on the cricket body surface. In the present study, we analyzed female and male cuticular substances in behavioral assays. Antennal contact stimulation using female forewings elicited a mating behavior in males, while that using male forewings

Masazumi Iwasaki; Chihiro Katagiri

2008-01-01

57

Sex Hormone Influence on Hepatitis in Young Male A\\/JCr Mice Infected with Helicobacter hepaticus  

Microsoft Academic Search

Hepatitis B virus (HBV), the leading cause of human hepatocellular carcinoma, is especially virulent in males infected at an early age. Likewise, the murine liver carcinogen Helicobacter hepaticus is most pathogenic in male mice infected before puberty. We used this model to investigate the influence of male sex hormone signaling on infectious hepatitis. Male A\\/JCr mice were infected with H.

Elizabeth J. Theve; Yan Feng; Koli Taghizadeh; Kathleen S. Cormier; David R. Bell; James G. Fox; Arlin B. Rogers

2008-01-01

58

The brain as the engine of sex differences in the organization of movement in rats.  

PubMed

Sex differences in the kinematic organization of non-reproductive behavior are often relegated to byproducts of sex differences in body morphology. We review evidence showing not only that male and female rats organize their posture and stepping differently during a variety of actions, but that these differences arise from sex differences in the organization of movement in the central nervous system (CNS). Indeed, the expression and choice of sex-typical patterns of movement can be altered by CNS injury. The pattern of hormonal regulation of these sex differences is also not organized as commonly held theory would predict. As expected, males castrated shortly after birth are female-typical in their motor organization. Females ovariectomized at birth, however, are male-typical in their patterns of movement. Thus, female-typical patterns of movement organization are not the default form, but rather are dependent on the effects of gonadal steroids to feminize the developing CNS. The implications of these findings are discussed with regards to our understanding of the evolution of sex differences in CNS anatomy and behavior both for animals and humans. PMID:18074218

Field, Evelyn F; Pellis, Sergio M

2008-02-01

59

Male sex work and HIV risk among young heroin users in Hanoi, Vietnam  

PubMed Central

The present study describes complex drug and sexual risk in a group of male sex workers (n=79) who were recruited in the context of a larger study of young heroin users in Hanoi, Vietnam (n=1270). Male sex workers were significantly more likely than male non-sex workers to be migrants (P<0.001) and to have unstable housing (P<0.001), to have lifetime exposure to marijuana (P<0.001), 3,4 methylenedioxymethamphetamine (MDMA, ecstasy) (P<0.01), amphetamines (P<0.05), cocaine (P<0.01) and morphine (P<0.001). Male sex workers are more likely to currently use MDMA (P<0.05), amphetamines (P<0.001), morphine (P<0.05) and to ‘smoke’ as their most frequent mode of heroin administration (P<0.01). Male sex workers are more likely to have both male and female concurrent sex partners (P<0.001), to have a history of sexual victimisation (P<0.001), to have had more than three different sex partners in the past 30 days (P<0.001), and to have had partners who injected drugs before sex (P<0.001) or who used drugs during sex (P<0.01). In their last sexual encounter with a client partner, approximately one-third (31.1%) reported having had receptive anal sex. In nearly three-quarters of these exchanges (71.4%), no condom was used. Similarly, in their last sexual encounter with a client partner, 42.2% reported having had insertive anal sex and in nearly half (47.4%) of these encounters no condom was used. Consistent with recent data from elsewhere in the region, there is an urgent need for additional research on male sex work in South-east Asia in order to properly situate behavioural interventions for male sex workers in this region. PMID:18082070

Clatts, Michael C.; Giang, Le M.; Goldsamt, Lloyd A.; Yi, Huso

2009-01-01

60

The Vomeronasal Organ of the Male Ferret  

Microsoft Academic Search

The vomeronasal organ (VNO) is known to play a major role in sexual behavior in many mammals. This study is the first report that the adult male ferret has a VNO, which is considerably smaller and morphologically different from the usually crescent- shaped epithelium in several mammalian species, particularly rodents. There were no differences in the size or structure of

Elke Weiler; Raimund Apfelbach; Albert I. Farbman

1999-01-01

61

Sex Chromosome-Specific Regulation in the Drosophila Male Germline But Little Evidence for Chromosomal  

E-print Network

Sex Chromosome-Specific Regulation in the Drosophila Male Germline But Little Evidence for Chromosomal Dosage Compensation or Meiotic Inactivation Colin D. Meiklejohn*, Emily L. Landeen, Jodi M. Cook, United States of America Abstract The evolution of heteromorphic sex chromosomes (e.g., XY in males or ZW

Dean, Matthew D.

62

Husbands' sex-role preferences and contraceptive intentions: The case of the male pill  

Microsoft Academic Search

Little attention has been given to examining the relationship between males' sex roles and their attitudes and behaviors regarding contraceptive issues. The present study addresses this shortcoming by examining the relationships among husbands' sex-role preferences, perceptions of contraceptive responsibility, and hypothetical intentions regarding the possible adoption of a male birth control pill. Data are drawn from a mailed survey of

William Marsiglio

1985-01-01

63

Sex differences in response to nonconspecific advertisement calls: receiver permissiveness in male and female tungara frogs  

E-print Network

Sex differences in response to nonconspecific advertisement calls: receiver permissiveness in male. Few studies, however, have investigated such differences and there is no consensus on which sex, evolutionary history has left a perceptual footprint on the brain of both sexes but the details seem to differ

Ryan, Michael J.

64

Male specific expression suggests role of DMRT1 in human sex determination  

Microsoft Academic Search

Sex determination in mammals is controlled by various transcription factors. Following the identification of SRY on the Y chromosome, several other factors have been identified. They can normally be identified as being involved in sex determination by the identification of sex reversal mutations or deletions, functional studies, and also by male-specific expression patterns in embryos. Here, it is shown that

Brigitte Moniot; Philippe Berta; Gerd Scherer; Peter Südbeck; Francis Poulat

2000-01-01

65

the DomeMales are lured byfood and sex into erotic contests and deadly brawls  

E-print Network

Dancing in the DomeMales are lured byfood and sex into erotic contests and deadly brawls by Paul J space, where they annually' reenact a silent, ancient drama of sex and combat. My study site in March, juveniles of both sexes live solitarily for a time and seek out sites for their own domed webs

Watson, Paul J.

66

An Instrument to Measure Safer Sex Strategies Used by Male Sex Workers  

Microsoft Academic Search

Several studies have related safe sex in the commercial sex encounter to the ability of sex workers to apply specific safer sex strategies. However, no instrument has been previously available to measure these skills. The Safer-Sex Strategy Scale (SSS) was developed for such purposes. The psychometric properties (reliability and validity) were evaluated with a sample of sex workers recruited from

Rodrigo Mariño; Jan Browne; Victor Minichiello

2000-01-01

67

Brood sex ratio and male UV ornamentation in blue tits ( Cyanistes caeruleus ): correlational evidence and an experimental test  

Microsoft Academic Search

Sex-allocation theory predicts that females paired to attractive males should bias the brood sex ratio towards male offspring,\\u000a as these would inherit the attractiveness of their father. We studied sex allocation based on male ornamentation in blue tits.\\u000a Brood sex ratios varied with male UV coloration in an age-dependent manner. For juvenile males, the proportion of sons increased\\u000a with increasing

Kaspar Delhey; Anne Peters; Arild Johnsen; Bart Kempenaers

2007-01-01

68

Men's constructions of masculinity and male sexuality through talk of buying sex.  

PubMed

Commercial sex is an everyday occurrence across a range of contexts in South Africa. In this paper we turn our attention to the often-marginalised role of the buyers of sex by drawing on narrative interviews with male clients of female sex workers recruited through online advertisements in order to explore the ways in which heterosexual men construct, negotiate and perform their masculinity and sexuality through talking about their experiences of paying for sex. We highlight parallels between men's narratives of paying for sex and dominant discourses of gender and heterosexuality. We show how men draw on heteronormative sexual scripts in constructing and making sense of paid sexual encounters and how men are simultaneously able to construct and enact a particular idealised version of masculinity and male sexuality through their talk on paying for sex. Finally, we discuss how online resources could be used more extensively in future research with the male clients of sex workers. PMID:25287270

Huysamen, Monique; Boonzaier, Floretta

2015-05-01

69

Oleic acid is a precursor of linoleic acid and the male sex pheromone in Nasonia vitripennis.  

PubMed

Linoleic acid (C18:2(?9,12), LA) is crucial for many cell functions in organisms. It has long been a paradigm that animals are unable to synthesize LA from oleic acid (C18:1(?9), OA) because they were thought to miss ?(12)-desaturases for inserting a double bound at the ?(12)-position. Today it is clear that this is not true for all animals because some insects and other invertebrates have been demonstrated to synthesize LA. However, the ability to synthesize LA is known in only five insect orders and no examples have been reported so far in the Hymenoptera. LA plays a particular role in the parasitic wasp Nasonia vitripennis, because it is the precursor of the male sex pheromone consisting of (4R,5R)- and (4R,5S)-5-hydroxy-4-decanolides. Here we demonstrate by stable isotope labeling that N. vitripennis is able to incorporate externally applied fully (13)C-labeled OA into the male sex pheromone suggesting that they convert initially OA into LA. To verify this assumption, we produced fly hosts (Lucilia caesar) which were experimentally enriched in (13)C-labeled OA and reared male parasitoids on these hosts. Chemical analysis of transesterified lipid raw extracts from hosts and parasitoids revealed that N. vitripennis but not L. caesar contained (13)C-labeled LA methyl ester. Furthermore, male wasps from the manipulated hosts produced significant amounts of (13)C-labeled sex pheromone. These results suggest that N. vitripennis possesses a ?(12)-desaturase. The additional fitness relevant function as pheromone precursor might have favored the evolution of LA biosynthesis in N. vitripennis to make the wasps independent of the formerly essential nutrient. PMID:24874439

Blaul, Birgit; Steinbauer, Robert; Merkl, Philipp; Merkl, Rainer; Tschochner, Herbert; Ruther, Joachim

2014-08-01

70

Sex chromosome synapsis and recombination in male guppies.  

PubMed

Guppy X and Y chromosomes represent an early stage in sex chromosome divergence. Synapsis and recombination between X and Y chromosomes attract special attention because recombination suppression promotes their differentiation, but previous studies have given contradictory results. Linkage analysis indicated that recombination between X and Y was extremely rare (<10%) and occurred in the medial part of the Y chromosome, while cytological analysis demonstrated regular association between the distal ends of the X and Y at diakinesis. In this study, we examine pairing and recombination between X and Y chromosomes using immunolocalization of MLH1 to mark recombination nodules, and genomic in situ hybridization with a male DNA probe to identify the Y-specific heterochromatic region. Pairing between X and Y is initiated distally. Single crossovers were detected in 87% of XY synaptonemal complexes, most often in the distal region and less frequently in a median position indicating that end-to-end associations between X and Y are chiasmatic. Thus, we suggest that the very low frequency of recombination detected by linkage analysis in a previous study resulted from a lack of informative markers in distal regions. PMID:25608108

Lisachov, Artem P; Zadesenets, Kira S; Rubtsov, Nikolay B; Borodin, Pavel M

2015-04-01

71

Sex Combs are Important for Male Mating Success in Drosophila melanogaster  

Microsoft Academic Search

The sex comb is one of the most rapidly evolving male-specific traits in Drosophila, making it an attractive model to study sexual selection and developmental evolution. Drosophila males use their sex combs to grasp the females’ abdomen and genitalia and to spread their wings prior to copulation. To test\\u000a the role of this structure in male mating success in Drosophila

Chen Siang Ng; Artyom Kopp

2008-01-01

72

From Client to Pimp: Male Violence against Female Sex Workers  

ERIC Educational Resources Information Center

The present study explores intimate partner violence (IPV) among female sex workers from the red-light area based in Mumbai, India. Using a grounded theory approach, in-depth interviews were conducted with ten sex workers to explore their experiences of IPV in the context of commercial sex work. Narratives were analyzed and themes constructed. A…

Karandikar, Sharvari; Prospero, Moises

2010-01-01

73

Role of insect sex pheromones in mating behavior. V. Profile of process on male flying approach toward sex pheromone source  

Microsoft Academic Search

Application of the kinetic theory of gas molecules to male zigzagging orientation, which is assumed as repeated encounter\\u000a between sex pheromone puff and a flying male moth, derived a linear relationship between the number of turnings and the distance\\u000a from the source where male began repeated turnings. Similar results are also obtained by computer simulation. This relationship\\u000a was already obtained

Yoshitoshi Hirooka

1986-01-01

74

Fluorochemicals used in food packaging inhibit male sex hormone synthesis  

SciTech Connect

Polyfluoroalkyl phosphate surfactants (PAPS) are widely used in food contact materials (FCMs) of paper and board and have recently been detected in 57% of investigated materials. Human exposure occurs as PAPS have been measured in blood; however knowledge is lacking on the toxicology of PAPS. The aim of this study was to elucidate the effects of six fluorochemicals on sex hormone synthesis and androgen receptor (AR) activation in vitro. Four PAPS and two metabolites, perfluorooctanoic acid (PFOA) and 8:2 fluorotelomer alcohol (8:2 FTOH) were tested. Hormone profiles, including eight steroid hormones, generally showed that 8:2 diPAPS, 8:2 monoPAPS and 8:2 FTOH led to decreases in androgens (testosterone, dehydroepiandrosterone, and androstenedione) in the H295R steroidogenesis assay. Decreases were observed for progesterone and 17-OH-progesterone as well. These observations indicated that a step prior to progestagen and androgen synthesis had been affected. Gene expression analysis of StAR, Bzrp, CYP11A, CYP17, CYP21 and CYP19 mRNA showed a decrease in Bzrp mRNA levels for 8:2 monoPAPS and 8:2 FTOH indicating interference with cholesterol transport to the inner mitochondria. Cortisol, estrone and 17?-estradiol levels were in several cases increased with exposure. In accordance with these data CYP19 gene expression increased with 8:2 diPAPS, 8:2 monoPAPS and 8:2 FTOH exposures indicating that this is a contributing factor to the decreased androgen and the increased estrogen levels. Overall, these results demonstrate that fluorochemicals present in food packaging materials and their metabolites can affect steroidogenesis through decreased Bzrp and increased CYP19 gene expression leading to lower androgen and higher estrogen levels. -- Highlights: ? Fluorochemicals found in 57% of paper and board food packaging were tested. ? Collectively six fluorochemicals were tested for antiandrogenic potential in vitro. ? Three out of six tested fluorochemicals inhibited synthesis of male sex hormones. ? Generally, levels of estrogens and cortisol stayed unaffected or increased. ? The effect on steroid synthesis was specific on gene expression of Bzrp and CYP19.

Rosenmai, A.K., E-mail: akjro@food.dtu.dk [Division of Toxicology and Risk Assessment, National Food Institute, Technical University of Denmark, DK-2860 Søborg (Denmark); Nielsen, F.K. [Section of Toxicology, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen (Denmark)] [Section of Toxicology, Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen (Denmark); Pedersen, M. [Division of Food Chemistry, National Food Institute, Technical University of Denmark, DK-2860 Søborg (Denmark)] [Division of Food Chemistry, National Food Institute, Technical University of Denmark, DK-2860 Søborg (Denmark); Hadrup, N. [Division of Toxicology and Risk Assessment, National Food Institute, Technical University of Denmark, DK-2860 Søborg (Denmark)] [Division of Toxicology and Risk Assessment, National Food Institute, Technical University of Denmark, DK-2860 Søborg (Denmark); Trier, X. [Division of Food Chemistry, National Food Institute, Technical University of Denmark, DK-2860 Søborg (Denmark)] [Division of Food Chemistry, National Food Institute, Technical University of Denmark, DK-2860 Søborg (Denmark); Christensen, J.H. [Department of Basic Sciences and Environment, Faculty of Life Sciences, University of Copenhagen, DK-1871 Frederiksberg C. (Denmark)] [Department of Basic Sciences and Environment, Faculty of Life Sciences, University of Copenhagen, DK-1871 Frederiksberg C. (Denmark); Vinggaard, A.M. [Division of Toxicology and Risk Assessment, National Food Institute, Technical University of Denmark, DK-2860 Søborg (Denmark)] [Division of Toxicology and Risk Assessment, National Food Institute, Technical University of Denmark, DK-2860 Søborg (Denmark)

2013-01-01

75

Perceived stigma of purchasing sex among Latino and non-Latino male clients of female sex workers in Tijuana, Mexico.  

PubMed

HIV prevention efforts must be comprehensive in their understanding of the factors involved in HIV risk. Male clients, who have received less research attention than female sex workers (FSWs), may experience stigma as a function of purchasing sex. Perceived stigma may be related to poor psychological outcomes, risky psychosexual characteristics, and higher drug and sexual risk behavior among male clients of FSWs. However, perceived stigma of purchasing sex may differ between clients of different ethnic groups. In the present study, we examine the correlates of perceived stigma of purchasing sex among Latino versus non-Latino male clients of FSWs in Tijuana, Mexico. Using time-location sampling, we recruited 375 male clients (323 Latino, 52 non-Latino) in Tijuana who completed a computerized survey on various measures. We measured perceived stigma of purchasing sex using three items we developed for this study. Using linear regression analyses we found that perceived stigma was associated with greater guilt, a greater feeling of escape from everyday life, and more negative condom attitudes among Latino clients. This was not found among non-Latino clients. Features of Latino culture, like machismo, and how they may relate to stigma of purchasing sex are discussed. PMID:23979714

Pitpitan, Eileen V; Strathdee, Steffanie A; Semple, Shirley J; Wagner, Karla D; Chavarin, Claudia V; Earnshaw, Valerie A; Patterson, Thomas L

2015-02-01

76

“In different situations, in different ways”: Male sex work in St. Petersburg, Russia  

PubMed Central

We conducted a qualitative study of male sex work in St. Petersburg Russia with a focus on social vulnerabilities, HIV risk perception, and HIV-related behaviours. In-depth interviews were conducted with individuals knowledgeable about male sex work through their profession (n=8) and with male sex workers themselves (n=12). Male sex work involves a variety of exchanges including expensive vacations, negotiated monetary amounts, or simply access to food. Methods to find clients included the Internet, social venues (e.g. gay clubs and bars), and public places (e.g. parks). Use of the Internet greatly facilitated male sex work in a variety of ways. It was used by both individuals and agencies to find clients, and appeared to be increasing. Men often reported not being professionally connected to other male sex workers and limited disclosure about their work. Many were aware of the work-related risks to personal safety including violence and robbery by clients. Perceived risk for HIV was mostly abstract, and several exceptions to condom use with clients were noted. Alcohol use was reported as moderate but consumed frequently in association with work. These data suggest that the most salient risks for male sex workers include professional isolation, threats to personal safety, limited perceived HIV risk, and sub-optimal levels of condom use. PMID:23464743

Niccolai, Linda M; King, Elizabeth J; Eritsyan, Ksenia; Safiullina, Liliya; Rusakova, Maia M

2013-01-01

77

Maternally inherited sex ratio distortion as a result of a male-killing agent in Spilostethus hospes (Hemiptera: Lygaeidae)  

Microsoft Academic Search

A family composed solely of daughters was produced by a pair of milkweed bugs, Spilostethus hospes (Hemiptera: Lygaeidae). The sex ratio among the offspring of the daughters was significantly female-biased, indicating that sex ratio distortion is heritable. The following results suggest that sex ratio distortion is caused by a maternally inherited, male-killing bacterium: females transmitted sex ratio distortion but males

Francis R Groeters

1996-01-01

78

Behavioral and psychosocial correlates of anal sex among male clients of female sex workers in tijuana, Mexico.  

PubMed

Most studies of heterosexual sex risk practices have focused on condomless vaginal sex despite evidence that condomless anal sex has a significantly higher risk of HIV transmission. The present study focused on male clients' anal sex practices with female sex workers (FSWs) in Tijuana, Mexico, where an HIV epidemic is growing among high-risk groups. Logistic regression analyses were used to identify psychosocial and behavioral correlates of anal sex among male clients. Our sample of HIV-negative men (N = 400) was predominantly Latino (87.5 %), born in Mexico (78.8 %), never married (36.8 %) or in a regular or common-law marriage (31.5 %), and employed (62.8 %), with an average age and education of 37.8 and 9.2 years, respectively. Eighty-nine percent identified as heterosexual and 11 % as bisexual. By design, 50 % of the sample resided in Tijuana and the other 50 % in San Diego County. Nearly half (49 %) reported at least one incident of anal sex with a FSW in Tijuana in the past 4 months; of those participants, 85 % reported that one or more of their anal sex acts with FSWs had been without a condom. In a multivariate model, anal sex with a FSW in the past 4 months was associated with bisexual identification, methamphetamine use with FSWs, repeat visits to the same FSW, higher scores on perceived stigma about being a client of FSWs, and sexual compulsivity. Prevention programs are needed that address the behavioral and psychosocial correlates of heterosexual anal sex in order to reduce HIV/STI transmission risk among male clients, FSWs, and their sexual network members. PMID:25795530

Semple, Shirley J; Strathdee, Steffanie A; Pitpitan, Eileen V; Chavarin, Claudia; Patterson, Thomas L

2015-05-01

79

Scales for sex experience for males and females  

Microsoft Academic Search

Tested 83 male and 101 female unmarried undergraduates on scales containing a range of heterosexual experiences. 2 12-item scales, one for males and one for females, were developed. Coefficients of reproducibility were .97 for both males and females, and the rank-order correlation between the ordering of items in male and female scales was .95.

Marvin Zuckerman

1973-01-01

80

Trait compensation and sex-specific aging of performance in male and female professional basketball players.  

PubMed

Phenotypic traits are often influenced by dynamic resource allocation trade-offs which, when occurring over the course of individual lifespan, may manifest as trait aging. Although aging is studied for a variety of traits that are closely tied to reproduction or reproductive effort, the aging of multiple traits related to fitness in other ways are less well understood. We took advantage of almost 30 years of data on human whole-organism performance in the National Basketball Association (USA) to examine trends of aging in performance traits associated with scoring. Given that patterns of aging differ between sexes in other animal species, we also analyzed a smaller dataset on players in the Women's National Basketball Association to test for potential sex differences in the aging of comparable traits. We tested the hypothesis that age-related changes in a specific aspect of overall performance can be compensated for by elevated expression of another, related aspect. Our analyses suggest that the aging of performance traits used in basketball is generally characterized by senescence in males, whereas age-related changes in basketball performance are less evident in females. Our data also indicate a different rate of senescence of different performance traits associated with scoring over a male's lifetime. PMID:24495052

Lailvaux, Simon P; Wilson, Robbie; Kasumovic, Michael M

2014-05-01

81

Sex-reversed mice: XX and XO males  

Microsoft Academic Search

An autosomally inherited condition is described in the mouse which causes genetic females to develop as phenotypic males. XX males are phenotypically normal with the exception of small testes, which, in the adult, are devoid of germ cells. During late fetal and early postnatal development, male-type germ cells are present but progressively become lost, so that none is present by

B. M. Cattanach; C. E. Pollard; S. G. Hawkes

1971-01-01

82

Sex- and Gonad-Affecting Scent Compounds and 3 Male Pheromones in the Rat  

PubMed Central

This study was aimed at identifying sex pheromones of the rat (Rattus norvegicus). We characterized the volatiles and semivolatiles of rat preputial gland and voided urine by using gas chromatography–mass spectrometry (GC–MS) and quantified them by their GC areas (abundances) and percentage of GC areas (relative abundances). Although all the compounds other than 4-heptanone and phenol detected were shared by males and females, the quantities for some of these sex-common compounds exhibited sexual dimorphism and decreased with gonadectomy. Thus, these compounds might be sex pheromones. Among them, squalene from preputial glands and 2-heptanone and 4-ethyl phenol from urine were 3 major compounds. They were richer in males and could be suppressed by castration. Adding any of the 3 compounds (at a concentration higher than its physiological level in male urine) to castrated male urine (CMU) increased the attractiveness of CMU to sex-naive females. Adding the 3 together (at the levels in normal male urine) to CMU significantly increased the attractiveness of CMU to females. However, such combination did not fully restore females' preference for urine from intact males, suggesting that some other trace compounds such as 4-heptanone and phenol might also play some roles in sex attractiveness. Thus, squalene, 2-heptanone, and 4-ethyl phenol were indeed male pheromone molecules in rats. Our study also indicates that E,E-?-farnesene and E-?-farnesene, both richer in females than males, might be putative female pheromones. PMID:18515819

Sun, Lixing; Zhang, Jin-Hua; Feng, Zhi-Yong

2008-01-01

83

Cloning of Taiwan water buffalo male-specific DNA sequence for sexing  

Microsoft Academic Search

Random amplified polymorphic DNA (RAPD) fingerprinting was carried out to investigate the sex-specific DNA sequence for sexing in Taiwan water buffalos. One hundred and forty random primers were used for RAPD-PCR (polymerase chain reaction). One of these primers, OPC-16, produced a 321bp fragment found only in tested males. This male-specific fragment was isolated and constructed into plasmids for nucleotide sequencing,

Yan-Ming Horng; Yi-Ting Chen; Chean-Ping Wu; Yu-Shine Jea; Mu-Chiou Huang

2004-01-01

84

The sex ratio and male-on-female intimate partner violence  

Microsoft Academic Search

Two divergent perspectives have been articulated in the literature regarding the effect that an unbalanced sex ratio is speculated to have on male-on-female intimate partner violence. Evolutionary psychology proffers that a high sex ratio (i.e., more men than women in the population) propagates competition among males for female mates. This competition for female mates is thought to engender sexual jealousy

Stewart J. D'Alessio; Lisa Stolzenberg

2010-01-01

85

Population differentiation in female sex pheromone and male preferences in a solitary bee  

Microsoft Academic Search

Population differentiation in female mating signals and associated male preferences can drive reproductive isolation among\\u000a segregated populations. We tested this assumption by investigating intraspecific variation in female sex pheromone and associated\\u000a male odour preferences among distant populations in the solitary bee Colletes cunicularius (L.) by using quantitative gas chromatography and by performing field bioassays with synthetic blends of key sex

Nicolas J. Vereecken; Jim Mant; Florian P. Schiestl

2007-01-01

86

Heritability of Plasma Sex Hormones and Hormone Binding Globulin in Adult Male Twins  

Microsoft Academic Search

Plasma sex hormone concentrations have been used as biomarkers in epidemiological studies of many conditions including cancer, obesity, bone density, and coronary heart disease. The objective of this anal- ysis was to estimate genetic and nongenetic influences on endogenous sex hormones (testosterone, estradiol, estrone, and SHBG) in a large sample of 532 adult white male twins (134 monozygotic and 132

Huijun Z. Ring; Christina N. Lessov; Terry Reed; Robert Marcus; Leah Holloway; Gary E. Swan; Dorit Carmelli

87

Male and Female Pathways through Four-Year Colleges: Disruption and Sex Stratification in Higher Education  

ERIC Educational Resources Information Center

Pathways through college vary by sex in ways that may contribute to the contemporary male-female gap in college graduation that favors women. Although past research has documented sex differences in college pathways, little research has investigated the underlying causes of this variation. Using data from the National Education Longitudinal Study,…

Ewert, Stephanie

2010-01-01

88

HIV Risk and Social Networks Among Male-to-Female Transgender Sex Workers in Boston, Massachusetts  

PubMed Central

Male-to-female transgender individuals who engage in sex work constitute a group at high risk for HIV infection in the United States. This mixed-methods formative study examined sexual risk among preoperative transgender male-to-female sex workers (N = 11) in Boston. More than one third of the participants were HIV-infected and reported a history of sexually transmitted diseases. Participants had a mean of 36 (SD = 72) transactional male sex partners in the past 12 months, and a majority reported at least one episode of unprotected anal sex. Qualitative themes included (a) sexual risk, (b) motivations for engaging in sex work, (c) consequences of sex work, (d) social networks (i.e., “trans mothers,” who played a pivotal role in initiation into sex work), and (e) potential intervention strategies. Results suggest that interventions with transgender male-to-female sex workers must be at multiple levels and address the psychosocial and environmental contexts in which sexual risk behavior occurs. PMID:19732696

Reisner, Sari L.; Mimiaga, Matthew J.; Bland, Sean; Mayer, Kenneth H.; Perkovich, Brandon; Safren, Steven A.

2013-01-01

89

Male only progeny in Anastrepha suspensa by RNAi-induced sex reversion of chromosomal females  

Microsoft Academic Search

In Tephritidae sex determination is established by orthologs to the Drosophila melanogaster transformer and transformer-2 genes, though the primary signals for sex determination differ. The presence of the Y chromosome in the tephritid species is critical for male differentiation, while the ratio of X chromosomes to autosome ploidy is critical in drosophilids. Here the isolation, expression and function of tra

Marc F. Schetelig; Andreina Milano; Giuseppe Saccone; Alfred M. Handler

90

Wolbachia, sex ratio bias and apparent male killing in the harlequin beetle riding pseudoscorpion  

Microsoft Academic Search

Bacterial endosymbionts that manipulate host reproduction are now known to be widespread in insects and other arthropods. Since they inhabit the cytoplasm and are maternally inherited, these microorganisms can enhance their fitness by biasing host sex ratio in favour of females. At its most extreme, sex ratio manipulation may be achieved by killing male embryos, as occurs in a number

D W Zeh; J A Zeh; M M Bonilla

2005-01-01

91

Functionally reproductive diploid and haploid males in an inbreeding hymenopteran with complementary sex determination  

Microsoft Academic Search

It has become a matter of orthodoxy that among wasps, ants, bees, and other insects in the order Hymenoptera, only uniparental haploid males that arise from unfertilized eggs are capable of reproduction. This idea is of interest because the best understood and perhaps most widespread sex determination system among these insects [known as single locus complementary sex determination (sl-CSD)] does

David P. Cowan; Julie K. Stahlhut

2004-01-01

92

The Relationship of Trauma Exposure to Sex Offending Behavior among Male Juvenile Offenders.  

ERIC Educational Resources Information Center

Study identifies ways that traumatic experiences and trauma-associated feelings can be offense triggers for juvenile sex offenders. Researchers interviewed the treating clinicians of 40 male juvenile sex offenders. Overall, clinicians identified prior trauma exposure as being related to the offense triggers in 85% of offenders. Implications for…

McMackin, Robert A.; Leisen, Mary Beth; Cusack, John R.; LaFratta, Joseph; Litwin, Peter

2002-01-01

93

Sex ratio and spatial distribution of male and female Antennaria dioica (Asteraceae) plants  

NASA Astrophysics Data System (ADS)

Sex ratio, sex spatial distribution and sexual dimorphism in reproduction and arbuscular mycorrhizal colonisation were investigated in the dioecious clonal plant Antennaria dioica (Asteraceae). Plants were monitored for five consecutive years in six study plots in Oulanka, northern Finland. Sex ratio, spatial distribution of sexes, flowering frequency, number of floral shoots and the number and weight of inflorescences were recorded. In addition, intensity of mycorrhizal fungi in the roots was assessed. Both sexes flowered each year with a similar frequency, but the overall genet sex ratio was strongly female-biased. The bivariate Ripley's analysis of the sex distribution showed that within most plots sexes were randomly distributed except for one plot. Sexual dimorphism was expressed as larger floral and inflorescence production and heavier inflorescences in males. In addition, the roots of both sexes were colonised to a similar extent by arbuscular mycorrhizal fungi. The female sex-biased flowering ratios reported are not consistent among years and cannot be explained in terms of spatial segregation of the sexes or sex lability. The possible reasons for the female-biased sex ratio are discussed.

Varga, Sandra; Kytöviita, Minna-Maarit

2011-09-01

94

Sex Chromosome  

NSDL National Science Digital Library

A sex chromosome is one of the two chromosomes that specify an organism's genetic sex. Humans have two kinds of sex chromosomes, one called X and the other Y. Normal females possess two X chromosomes and normal males one X and one Y.

Darryl Leja (National Human Genome Research Institute REV)

2005-04-14

95

Hepatic injury induces contrasting response in liver and kidney to chemicals that are metabolically activated: Role of male sex hormone  

SciTech Connect

Injury to liver, resulting in loss of its normal physiological/biochemical functions, may adversely affect a secondary organ. We examined the response of the liver and kidney to chemical substances that require metabolic activation for their toxicities in mice with a preceding liver injury. Carbon tetrachloride treatment 24 h prior to a challenging dose of carbon tetrachloride or acetaminophen decreased the resulting hepatotoxicity both in male and female mice as determined by histopathological examination and increases in serum enzyme activities. In contrast, the renal toxicity of the challenging toxicants was elevated markedly in male, but not in female mice. Partial hepatectomy also induced similar changes in the hepatotoxicity and nephrotoxicity of a challenging toxicant, suggesting that the contrasting response of male liver and kidney was associated with the reduction of the hepatic metabolizing capacity. Carbon tetrachloride pretreatment or partial hepatectomy decreased the hepatic xenobiotic-metabolizing enzyme activities in both sexes but elevated the renal p-nitrophenol hydroxylase, p-nitroanisole O-demethylase and aminopyrine N-demethylase activities significantly only in male mice. Increases in Cyp2e1 and Cyp2b expression were also evident in male kidney. Castration of males or testosterone administration to females diminished the sex-related differences in the renal response to an acute liver injury. The results indicate that reduction of the hepatic metabolizing capacity induced by liver injury may render secondary target organs susceptible to chemical substances activated in these organs. This effect may be sex-specific. It is also suggested that an integrated approach should be taken for proper assessment of chemical hazards.

Kim, Young C. [College of Pharmacy, Seoul National University, San 56-1 Shinrim-Dong, Kwanak-Ku, Seoul (Korea, Republic of)], E-mail: youckim@snu.ac.kr; Yim, Hye K.; Jung, Young S. [College of Pharmacy, Seoul National University, San 56-1 Shinrim-Dong, Kwanak-Ku, Seoul (Korea, Republic of); Park, Jae H. [College of Veterinary Medicine, Seoul National University, San 56-1 Shinrim-Dong, Kwanak-Ku, Seoul (Korea, Republic of); Kim, Sung Y. [College of Pharmacy, Wonkwang University, 344-2 Shinyong-Dong, Iksan (Korea, Republic of)

2007-08-15

96

The Sicker Sex: Understanding Male Biases in Parasitic Infection, Resource Allocation and Fitness  

PubMed Central

The “sicker sex” idea summarizes our knowledge of sex biases in parasite burden and immune ability whereby males fare worse than females. The theoretical basis of this is that because males invest more on mating effort than females, the former pay the costs by having a weaker immune system and thus being more susceptible to parasites. Females, conversely, have a greater parental investment. Here we tested the following: a) whether both sexes differ in their ability to defend against parasites using a natural host-parasite system; b) the differences in resource allocation conflict between mating effort and parental investment traits between sexes; and, c) effect of parasitism on survival for both sexes. We used a number of insect damselfly species as study subjects. For (a), we quantified gregarine and mite parasites, and experimentally manipulated gregarine levels in both sexes during adult ontogeny. For (b), first, we manipulated food during adult ontogeny and recorded thoracic fat gain (a proxy of mating effort) and abdominal weight (a proxy of parental investment) in both sexes. Secondly for (b), we manipulated food and gregarine levels in both sexes when adults were about to become sexually mature, and recorded gregarine number. For (c), we infected male and female adults of different ages and measured their survival. Males consistently showed more parasites than females apparently due to an increased resource allocation to fat production in males. Conversely, females invested more on abdominal weight. These differences were independent of how much food/infecting parasites were provided. The cost of this was that males had more parasites and reduced survival than females. Our results provide a resource allocation mechanism for understanding sexual differences in parasite defense as well as survival consequences for each sex. PMID:24194830

Córdoba-Aguilar, Alex; Munguía-Steyer, Roberto

2013-01-01

97

The C. elegans Male Exercises Directional Control during Mating through Cholinergic Regulation of Sex-Shared Command Interneurons  

PubMed Central

Background Mating behaviors in simple invertebrate model organisms represent tractable paradigms for understanding the neural bases of sex-specific behaviors, decision-making and sensorimotor integration. However, there are few examples where such neural circuits have been defined at high resolution or interrogated. Methodology/Principal Findings Here we exploit the simplicity of the nematode Caenorhabditis elegans to define the neural circuits underlying the male’s decision to initiate mating in response to contact with a mate. Mate contact is sensed by male-specific sensilla of the tail, the rays, which subsequently induce and guide a contact-based search of the hermaphrodite’s surface for the vulva (the vulva search). Atypically, search locomotion has a backward directional bias so its implementation requires overcoming an intrinsic bias for forward movement, set by activity of the sex-shared locomotory system. Using optogenetics, cell-specific ablation- and mutant behavioral analyses, we show that the male makes this shift by manipulating the activity of command cells within this sex-shared locomotory system. The rays control the command interneurons through the male-specific, decision-making interneuron PVY and its auxiliary cell PVX. Unlike many sex-shared pathways, PVY/PVX regulate the command cells via cholinergic, rather than glutamatergic transmission, a feature that likely contributes to response specificity and coordinates directional movement with other cholinergic-dependent motor behaviors of the mating sequence. PVY/PVX preferentially activate the backward, and not forward, command cells because of a bias in synaptic inputs and the distribution of key cholinergic receptors (encoded by the genes acr-18, acr-16 and unc-29) in favor of the backward command cells. Conclusion/Significance Our interrogation of male neural circuits reveals that a sex-specific response to the opposite sex is conferred by a male-specific pathway that renders subordinate, sex-shared motor programs responsive to mate cues. Circuit modifications of these types may make prominent contributions to natural variations in behavior that ultimately bring about speciation. PMID:23577128

Sherlekar, Amrita L.; Janssen, Abbey; Siehr, Meagan S.; Koo, Pamela K.; Caflisch, Laura; Boggess, May; Lints, Robyn

2013-01-01

98

Sexually dimorphic neurons in the ventromedial hypothalamus govern mating in both sexes and aggression in males  

PubMed Central

SUMMARY Sexual dimorphisms in the brain underlie behavioral sex differences, but the function of individual sexually dimorphic neuronal populations is poorly understood. Neuronal sexual dimorphisms typically represent quantitative differences in cell number, gene expression, or other features, and it is unknown if these dimorphisms control sex-typical behavior in one sex exclusively or in both sexes. The progesterone receptor (PR) controls female sexual behavior, and we find many sex differences in number, distribution, or projections of PR-expressing neurons in the adult mouse brain. We have ablated one such PR-expressing neuronal population located in the ventromedial hypothalamus (VMH) using a novel genetic strategy. Ablation of these neurons in females greatly diminishes sexual receptivity. Strikingly, the corresponding ablation in males reduces mating and aggression. Our findings reveal the functions of a molecularly-defined, sexually dimorphic neuronal population in the brain. Moreover we show that sexually dimorphic neurons can control distinct sex-typical behaviors in both sexes. PMID:23663785

Yang, Cindy F.; Chiang, Michael; Gray, Daniel C.; Prabhakaran, Mahalakshmi; Alvarado, Maricruz; Juntti, Scott A.; Unger, Elizabeth K.; Wells, James A.; Shah, Nirao M.

2013-01-01

99

Women's Motivations to Have Sex in Casual and Committed Relationships with Male and Female Partners.  

PubMed

Women report a wide variety of reasons to have sex (e.g., Meston & Buss, 2010), and while it is reasonable to assume that those reasons may vary based on the context of the relationship, this assumption has not yet been tested. The purpose of this study was to explore how relationship type, sexual attraction, and the gender of one's partner interact and affect the sexual motivations of women. A total of 510 women (361 who reported exclusively other-sex attraction and 149 who reported same-sex/bisexual attraction) completed the YSEX? questionnaire. Participants rated their sexual motivations for casual sex and sex in a committed relationship with male and/or female partners, depending on reported sexual attraction. Results showed that relationship type affected reported motivation for sex: physical motivations were more strongly endorsed for casual sex, whereas emotional motivations were more strongly endorsed for sex in committed relationships. No significant differences in motivation were reported between women who reported same-sex attraction and those who did not. Women who reported bisexual attraction and identified as being lesbian, bisexual, or another sexual minority reported no significant differences in motivation for sex with male or female partners. The results of this study highlight the importance of relationship context when discussing sexual motivation and suggest a high degree of similarity in motivation for women, regardless of sexual orientation or gender of partner. PMID:25567073

Armstrong, Heather L; Reissing, Elke D

2015-05-01

100

Male-biased sex ratio: why and what consequences for the genus Schistosoma?  

PubMed

Schistosomes are the cause of the most significant helminth disease of humans. Their unusual sexual biology is intriguing. Instead of being hermaphroditic, as is the rule in other trematode species, they are gonochoric. Furthermore, their mating system is considered to be monogamous, a characteristic shared by only 1% of living species, and their sex ratio is male-biased. In this paper we propose an explanation of the origin of the male-biased sex ratio in schistosomes and highlight the ecological and evolutionary consequences of this bias. We argue that schistosome gonochorism, monogamy and the biased sex ratio can be integrated into a single evolutionary scheme. PMID:20006552

Beltran, Sophie; Boissier, Jérôme

2010-02-01

101

Tribolium castaneum Transformer-2 regulates sex determination and development in both males and females.  

PubMed

Tribolium castaneum Transformer (TcTra) is essential for female sex determination and maintenance through the regulation of sex-specific splicing of doublesex (dsx) pre-mRNA. In females, TcTra also regulates the sex-specific splicing of its own pre-mRNA to ensure continuous production of functional Tra protein. Transformer protein is absent in males and hence dsx pre-mRNA is spliced in a default mode. The mechanisms by which males inhibit the production of functional Tra protein are not known. Here, we report on functional characterization of transformer-2 (tra-2) gene (an ortholog of Drosophila transformer-2) in T. castaneum. RNA interference-mediated knockdown in the expression of gene coding for tra-2 in female pupae or adults resulted in the production of male-specific isoform of dsx and both female and male isoforms of tra suggesting that Tra-2 is essential for the female-specific splicing of tra and dsx pre-mRNAs. Interestingly, knockdown of tra-2 in males did not affect the splicing of dsx but resulted in the production of both female and male isoforms of tra suggesting that Tra-2 suppresses female-specific splicing of tra pre-mRNA in males. This dual regulation of sex-specific splicing of tra pre-mRNA ensures a tight regulation of sex determination and maintenance. These data suggest a critical role for Tra-2 in suppression of female sex determination cascade in males. In addition, RNAi studies showed that Tra-2 is also required for successful embryonic and larval development in both sexes. PMID:24056158

Shukla, Jayendra Nath; Palli, Subba Reddy

2013-12-01

102

Sex organ determination and differentiation in the dioecious plant Melandrium album ( Silene latifolia ): a cytological and histological analysis  

Microsoft Academic Search

Melandrium album (Silene alba) is a dioecious plant with heteromorphic sex chromosomes (XY system). Sexual dimorphism is a result of developmental blocks\\u000a in male or female reproductive organ formation within young bipotential flower buds. Progress in understanding the genetic\\u000a and molecular mechanisms controlling sex determination in this species relies on a detailed description of developmental timing\\u000a in the two sexes,

Isabelle Farbos; Margarida Oliveira; Ioan Negrutiu; A. Mouras

1997-01-01

103

SEX HORMONES DURING ALCOHOL WITHDRAWAL: A LONGITUDINAL STUDY OF 29 MALE ALCOHOLICS DURING DETOXIFICATION  

Microsoft Academic Search

It is a well-known fact that alcohol affects sex hormone levels in males. Even in the absence of liver dysfunction, there is still a direct toxic effect of ethanol on testosterone synthesis resulting in acutely decreased values. This study is based on 29 male alcoholics without severe signs of liver disease treated on the alcohol detoxification ward at Huddinge hospital

JAAN RUUSA; BO BERGMAN; MONA-LISA SUNDELL

104

Sex workers’ non-commercial male partners who inject drugs report higher risk sexual behaviors  

PubMed Central

Female sex workers (FSWs) are less likely to use condoms with non-commercial male partners than clients. We compare non-commercial male partners who do and do not inject drugs in Tijuana and Ciudad Juárez, Mexico. Sexual risk behaviors were more prevalent among injectors, who could promote HIV/STI transmission in this region. PMID:24275732

Robertson, Angela M.; Syvertsen, Jennifer L.; Palinkas, Lawrence A.; Vera, Alicia; Rangel, Gudelia; Martinez, Gustavo; Strathdee, Steffanie A

2014-01-01

105

Serological evidence for H-Y antigen in Sxr, XX sex-reversed phenotypic males  

Microsoft Academic Search

IT is generally considered that the Y chromosome is necessary for the development of the mammalian testis and the consequent male phenotype. Exceptions occasionally occur in man and other animals, where a male phenotype is associated with an apparently normal female karyotype. In some instances it has been possible to show that such ``sex reversal'' has an autosomal genetic basis.

Dorothea Bennett; Bonnie J. Mathieson; Margrit Scheid; Kaichiro Yanagisawa; D A Boyse; STEPHEN WACHTEL; BRUCE M. CATTANACH

1977-01-01

106

Male adolescent birth control behavior: The importance of developmental factors and sex differences  

Microsoft Academic Search

A survey of sex and birth control behavior of 51 male adolescents aged 15–17 was conducted utilizing a structured interview protocol. The purpose of the study was to describe male adolescent birth control behavior incorporating developmental issues, and to interpret the findings in light of what is known about female birth control behavior. Based on research with teenage females, three

Donald D. Cohen; Ryda D. Rose

1984-01-01

107

Attitudes of male and female cadets toward military sex integration  

Microsoft Academic Search

Two studies examine the attitudes of male and female Army ROTC cadets toward the movement of women into nontraditional and leadership positions in the military. As expected, female cadets reacted more favorably toward women than did male cadets. The time spent in sexually integrated school year ROTC units did not appear to influence opinions, while experience of the integrated summer

Laurie Larwood; Eric Glasser; Robert McDonald

1980-01-01

108

Male and Female Suicide Bombers: Different Sexes, Different Reasons?  

Microsoft Academic Search

This article analyzes the motivations and recruitment of female suicide terrorists. Biographical accounts of 30 female and 30 male suicide terrorists were coded for method of recruitment, motivation for attack, and outcome of attack. A log-linear analysis found that female suicide terrorists were motivated more by Personal events, whereas males were motivated more by Religious\\/nationalistic factors. Females were equally likely

Karen Jacques; Paul J. Taylor

2008-01-01

109

Mental Health and Sexual Identity in a Sample of Male Sex Workers in the Czech Republic  

PubMed Central

Background Previous qualitative research has examined male sex workers in the Czech Republic, but this mapping study is the first to investigate male sex work in a quantitative research design and focus on the mental health of these sex workers. This study also examines male sex workers’ mental health problems in relation to their sexual identity or orientation. Material/Methods A sample of Czech male sex workers (N=40) were examined on a range of sexual and psychological variables using a quantitative survey administered face-to-face. The study employed locally validated versions of Beck’s Depression Inventory and Zung’s Self-Report Anxiety Scale. Results The results indicate that for homosexuals, working as a male sex worker is not related to any serious mental health problems. However, those identifying as heterosexual and bisexual more frequently reported symptoms of depression and bisexuals showed significantly more anxiety. Conclusions These findings suggest sexual identity is an important issue to consider when addressing the mental health needs of this population. PMID:25239091

Bar-Johnson, Michael; Weiss, Petr

2014-01-01

110

Persistent organic pollutants and male reproductive health  

PubMed Central

Environmental contaminants such as persistent organic pollutants (POPs) are man-made bioaccumulative compounds with long half-lives that are found throughout the world as a result of heavy use in a variety of consumer products during the twentieth century. Wildlife and animal studies have long suggested adverse effects of exposure to these compounds on human reproductive health, which, according to the endocrine disrupter hypothesis, are ascribed to the compounds’ potential to interfere with endocrine signaling, especially when exposure occurs during certain phases of fetal and childhood development. An extensive number of epidemiological studies have addressed the possible effects of exposure to POPs on male reproductive health, but the results are conflicting. Thus far, most studies have focused on investigating exposure and the different reproductive health outcomes during adulthood. Some studies have addressed the potential harmful effects of fetal exposure with respect to malformations at birth and/or reproductive development, whereas only a few studies have been able to evaluate whether intrauterine exposure to POPs has long-term consequences for male reproductive health with measurable effects on semen quality markers and reproductive hormone levels in adulthood. Humans are not exposed to a single compound at a time, but rather, to a variety of different substances with potential divergent hormonal effects. Hence, how to best analyze epidemiological data on combined exposures remains a significant challenge. This review on POPs will focus on current knowledge regarding the potential effects of exposure to POPs during fetal and childhood life and during adulthood on male reproductive health, including a critical revision of the endocrine disruption hypothesis, a comment on pubertal development as part of reproductive development and a comment on how to account for combined exposures in epidemiological research. PMID:24369135

Vested, Anne; Giwercman, Aleksander; Bonde, Jens Peter; Toft, Gunnar

2014-01-01

111

The possibility of sex and nymph discrimination by the male cockroach, Nauphoeta cinerea  

Microsoft Academic Search

The possibility of sex and nymph discrimination by males was investigated in the cockroach,Nauphoeta cinerea (Olivier). A sexually mature male takes a courting position toward a sexually mature female when he comes into contact with\\u000a her and recognizes her through antennal contact. In contrast, males often behave aggressively toward each other: they bite\\u000a at each others; wings and\\/or legs, chase

Masao Fukui; Shozo Takahashi

1991-01-01

112

Observations on sex ratio and behavior of males in Xyleborinus saxesenii Ratzeburg (Scolytinae, Coleoptera)  

PubMed Central

Abstract Strongly female-biased sex ratios are typical for the fungalfeeding haplodiploid Xyleborini (Scolytinae, Coleoptera), and are a result of inbreeding and local mate competition (LMC). These ambrosia beetles are hardly ever found outside of trees, and thus male frequency and behavior have not been addressed in any empirical studies to date. In fact, for most species the males remain undescribed. Data on sex ratios and male behavior could, however, provide important insights into the Xyleborini’s mating system and the evolution of inbreeding and LMC in general. In this study, I used in vitro rearing methods to obtain the first observational data on sex ratio, male production, male and female dispersal, and mating behavior in a xyleborine ambrosia beetle. Females of Xyleborinus saxesenii Ratzeburg produced between 0 and 3 sons per brood, and the absence of males was relatively independent of the number of daughters to be fertilized and the maternal brood sex ratio. Both conformed to a strict LMC strategy with a relatively precise and constant number of males. If males were present they eclosed just before the first females dispersed, and stayed in the gallery until all female offspring had matured. They constantly wandered through the gallery system, presumably in search of unfertilized females, and attempted to mate with larvae, other males, and females of all ages. Copulations, however, only occurred with immature females. From galleries with males, nearly all females dispersed fertilized. Only a few left the natal gallery without being fertilized, and subsequently went on to produce large and solely male broods. If broods were male-less, dispersing females always failed to found new galleries. PMID:21594184

H.W. Biedermann, Peter

2010-01-01

113

Sex hormones and male homosexuality in comparative perspective  

Microsoft Academic Search

Animal research has demonstrated the modifiability of sex-dimorphic mating behavior by hormone and brain manipulation, especially in subprimate mammals, and has led to radical attempts at treating human homosexuality by psychosurgery and to the suggestion of preventing homosexuality by prenatal hormone manipulation. This article reviews psychoendocrine studies of human homosexuality — the effects of hormone treatments on sexual orientation, the

Heino F. L. Meyer-Bahlburg

1977-01-01

114

Motivational Counseling: Implications for Counseling Male Juvenile Sex Offenders  

ERIC Educational Resources Information Center

Juvenile sex offenders (JSOs) often appear unmotivated to change, which thus necessitates a therapeutic approach that matches "resistant" client characteristics. In this article, the authors review common traits of JSOs, introduce motivational counseling as an effective treatment modality, and offer a case illustration. (Contains 1 table and 1…

Patel, Samir H.; Lambie, Glenn W.; Glover, Michelle Muenzenmeyer

2008-01-01

115

New Insights into the Regulation of Mammalian Sex Determination and Male Sex Differentiation  

Microsoft Academic Search

In mammals, sex development is a genetically and hormonally controlled process that begins with the establishment of chromosomal or genetic sex (XY or XX) at conception. At approximately 6 to 7 weeks of human gestation or embryonic day e11.5 in the mouse, expression of the Y chromosome-linked sex determining gene called SRY (described in detail in this chapter) then initiates

Robert S. Viger; David W. Silversides; Jacques J. Tremblay

2005-01-01

116

Male facial attractiveness and masculinity may provide sex- and culture-independent cues to semen quality.  

PubMed

Phenotype-linked fertility hypothesis (PLFH) predicts that male secondary sexual traits reveal honest information about male fertilization ability. However, PLFH has rarely been studied in humans. The aim of the present study was to test PLFH in humans and to investigate whether potential ability to select fertile partners is independent of sex or cultural background. We found that on the contrary to the hypothesis, facial masculinity was negatively associated with semen quality. As increased levels of testosterone have been demonstrated to impair sperm production, this finding may indicate a trade-off between investments in secondary sexual signalling (i.e. facial masculinity) and fertility or status-dependent differences in investments in semen quality. In both sexes and nationalities (Spanish and Colombian), ranked male facial attractiveness predicted male semen quality. However, Spanish males and females estimated facial images generally more attractive (gave higher ranks) than Colombian raters, and in both nationalities, males gave higher ranks than females. This suggests that male facial cues may provide culture- and sex-independent information about male fertility. However, our results also indicate that humans may be more sensitive to facial attractiveness cues within their own populations and also that males may generally overestimate the attractiveness of other men to females. PMID:25056484

Soler, C; Kekäläinen, J; Núñez, M; Sancho, M; Álvarez, J G; Núñez, J; Yaber, I; Gutiérrez, R

2014-09-01

117

Phf7 controls male sex determination in the Drosophila germline.  

PubMed

Establishment of germline sexual identity is critical for production of male and female germline stem cells, as well as sperm versus eggs. Here we identify PHD Finger Protein 7 (PHF7) as an important factor for male germline sexual identity in Drosophila. PHF7 exhibits male-specific expression in early germ cells, germline stem cells, and spermatogonia. It is important for germline stem cell maintenance and gametogenesis in males, whereas ectopic expression in female germ cells ablates the germline. Strikingly, expression of PHF7 promotes spermatogenesis in XX germ cells when they are present in a male soma. PHF7 homologs are also specifically expressed in the mammalian testis, and human PHF7 rescues Drosophila Phf7 mutants. PHF7 associates with chromatin, and both the human and fly proteins bind histone H3 N-terminal tails with a preference for dimethyl lysine 4 (H3K4me2). We propose that PHF7 acts as a conserved epigenetic "reader" that activates the male germline sexual program. PMID:22595675

Yang, Shu Yuan; Baxter, Ellen M; Van Doren, Mark

2012-05-15

118

Phf7 controls male sex determination in the Drosophila germline  

PubMed Central

Summary Establishment of germline sexual identity is critical for production of male and female germline stem cells, and sperm vs. eggs. Here we identify PHD Finger Protein 7 (PHF7) as an important factor for male germline sexual identity in Drosophila. PHF7 exhibits male-specific expression in early germ cells, germline stem cells and spermatogonia. It is required for germline stem cell maintenance and gametogenesis in males, whereas ectopic expression in female germ cells ablates the germline. Strikingly, expression of PHF7 promotes spermatogenesis in XX germ cells when they are present in a male soma. PHF7 homologs are also specifically expressed in the mammalian testis, and human PHF7 rescues Drosophila Phf7 mutants. PHF7 associates with chromatin and both the human and fly proteins bind histone H3 N-terminal tails with a preference for dimethyl lysine 4 (H3K4me2). We propose that PHF7 acts as a conserved epigenetic “reader” that activates the male germline sexual program. PMID:22595675

Yang, Shu Yuan; Baxter, Ellen M.; Van Doren, Mark

2013-01-01

119

Alcohol Use Among Female Sex Workers and Male Clients: An Integrative Review of Global Literature  

PubMed Central

Aims: To review the patterns, contexts and impacts of alcohol use associated with commercial sex reported in the global literature. Methods: We identified peer-reviewed English-language articles from 1980 to 2008 reporting alcohol consumption among female sex workers (FSWs) or male clients. We retrieved 70 articles describing 76 studies, in which 64 were quantitative (52 for FSWs, 12 for male clients) and 12 qualitative. Results: Studies increased over the past three decades, with geographic concentration of the research in Asia and North America. Alcohol use was prevalent among FSWs and clients. Integrating quantitative and qualitative studies, multilevel contexts of alcohol use in the sex work environment were identified, including workplace and occupation-related use, the use of alcohol to facilitate the transition into and practice of commercial sex among both FSWs and male clients, and self-medication among FSWs. Alcohol use was associated with adverse physical health, illicit drug use, mental health problems, and victimization of sexual violence, although its associations with HIV/sexually transmitted infections and unprotected sex among FSWs were inconclusive. Conclusions: Alcohol use in the context of commercial sex is prevalent, harmful among FSWs and male clients, but under-researched. Research in this area in more diverse settings and with standardized measures is required. The review underscores the importance of integrated intervention for alcohol use and related problems in multilevel contexts and with multiple components in order to effectively reduce alcohol use and its harmful effects among FSWs and their clients. PMID:20089544

Li, Qing; Li, Xiaoming; Stanton, Bonita

2010-01-01

120

On becoming a male sex worker in Mysore: sexual subjectivity, "empowerment," and community-based HIV prevention research.  

PubMed

Growing public health attention has been placed on the HIV vulnerability of males who sell sex to males in India. However, there is little research that outlines the trajectories through which males come to be involved in practicing sex work in India. Locating "male sex work" within a vibrant social, political, and erotic landscape, this article explores the intertwining of "sexual subjectivity" and "sex work." The authors refer to 70 sexual life histories generated from research conducted in Mysore to unsettle dominant public health notions that regard male sex work as rooted solely in poverty or as a decontexualized "behavioral risk factor." Such perspectives are countered by demonstrating how male sex work in Mysore encompasses a complex interplay between self-realization, sexual desire, social interaction, and public health discourse. Local conceptualizations of selfhood are discussed to suggest the limitations of prevailing empowerment discourses that advance Western notions of individuality. PMID:19562953

Lorway, Robert; Reza-Paul, Sushena; Pasha, Akram

2009-06-01

121

Where have all the females gone? Male biased sex-ratio in Arctodiaptomus alpinus (Imhof, 1885) in alpine lakes  

Microsoft Academic Search

In populations with both males and females sex-ratio is one of the driving forces of population dynamics. It influences fecundity, inbreeding and social interactions. Sex-ratio is affected by several biotic and abiotic factors, either by selective killing of one sex or by inducing migrations. In alpine lakes of Triglav National Park, Slovenia, an extremely male biased sex-ratio in Arctodiaptomus alpinus

U. Zibrat; A. Brancelj

2009-01-01

122

Male Gender Role Conflict, Gay Men, and Same-Sex Romantic Relationships  

Microsoft Academic Search

Some theorists have suggested that the traditionally socialized male reluctance to express intimacy is compounded within gay men's same-sex romantic relationships. In both Study 1 and Study 2, analysis-of-variance comparisons between single gay men and gay men in a same-sex relationship failed to confirm this assertion. At the same time, hierarchical regression results demonstrated a small negative relationship between the

Stephen R. Wester; David R. Pionke; David L. Vogel

2005-01-01

123

Male and female mate choice affects offspring quality in a sex-role-reversed pipefish.  

PubMed Central

Where both sexes invest substantially in offspring, both females and males should discriminate between potential partners when choosing mates. The degree of choosiness should relate to the costs of choice and to the potential benefits to be gained. We measured offspring quality from experimentally staged matings with preferred and non-preferred partners in a sex-role-reversed pipefish, Syngnathus typhle L. Here, a substantial male investment in offspring results in a lower potential reproductive rate in males than in females, and access to males limits female reproductive success rather than vice versa. Thus, males are choosier than females and females compete more intensely over mates than do males. Broods from preferred matings were superior at escaping predation, when either males or females were allowed to choose a partner. However, only 'choosing' females benefited in terms of faster-growing offspring. Our results have important implications for mate-choice research: here we show that even the more competitive and less choosy sex may contribute significantly to sexual selection through mate choice. PMID:11413626

Sandvik, M; Rosenqvist, G; Berglund, A

2000-01-01

124

Sex differences in flea infections among rodent hosts: is there a male bias?  

PubMed

Recognizing patterns of parasite distribution among wildlife hosts is of major importance due to growing risk of transmission of zoonotic diseases to humans. Thus, sex-dependent parasite distribution in higher vertebrates is extensively studied, and males are often found more parasitized than females. Male-biased parasitism may be the result of weaker immunocompetence of male hosts owing to the immunosuppressive effect of androgens. Moreover, larger hosts (males) may demonstrate higher parasite infestation levels than smaller individuals (females), as they constitute a better nutritional resource for parasites and provide them with a greater variety of niches. In the present work, we investigated sex-dependent patterns of flea distribution among three common rodent species (Apodemus agrarius, Apodemus flavicollis, and Myodes glareolus). We hypothesized that males have a higher flea infestation than females. We confirm male-biased parasitism in A. agrarius and M. glareolus, but not in A. flavicollis. Additionally, flea infestation increased with body mass in A. agrarius, but not in A. flavicollis and M. glareolus. The detected differences in parasite distribution among sexes are probably the result of immunosuppressive effects of androgens and spatial behavior of males. PMID:25410932

Kowalski, Krzysztof; Bogdziewicz, Micha?; Eichert, Urszula; Rychlik, Leszek

2015-01-01

125

A cause for concern: male couples' sexual agreements and their use of substances with sex.  

PubMed

Substance use is strongly associated with HIV risk among gay men. Many gay couples establish sexual agreements. However, little is known about gay couples' use of substances with sex, and whether substance use is associated with couples' agreements. The present study assessed whether gay couples' use of substances with sex was associated with their establishment of, type of, and adherence to, a sexual agreement. Dyadic data from 275 HIV-negative US gay couples were collected online in a nation-wide, cross-sectional study, and analyzed at the couple-level. Findings revealed that couples with an established agreement, and a recently broken agreement, were more likely to have used amyl nitrates and marijuana with sex within their relationship. This same trend was also noted, but for alcohol use with sex outside of couples' relationships. Further research is urgently needed to examine the fluidity of HIV-negative gay male couples' sexual agreements and substance use with sex. PMID:24584415

Mitchell, Jason W; Boyd, Carol; McCabe, Sean; Stephenson, Rob

2014-07-01

126

The trap of sex in social insects: from the female to the male perspective.  

PubMed

The phenotype of male Hymenoptera and the peculiar role of males has been neglected and greatly understudied, given the spectacular cooperative behavior of female social insects. In social insects there has been considerable progress in understanding the molecular mechanisms behind haplodiploid sex determination but, beyond that, very little is known concerning the neural, endocrine, and genetic correlates of sexual selection in males. An opportunity is being missed: the male phenotype in Hymenoptera is a natural experiment to compare the drives of natural versus sexual selection. In contrast to females, males do not work, they usually display far from the nest to gain mates, compete among rivals in nuptial flights or for a symbolic territory at leks, and engage in direct or ritualized conflicts. By comparing the available data on male paper wasps with studies on other social Hymenoptera, we summarize what we currently know about the physical, hormonal, neural and behavioral traits in a model system appropriate to examine current paradigms on sexual selection. Here we review male behavior in social Hymenoptera beyond sex stereotypes: the subtle role of "drones" in the colony, the lack of armaments and ornaments, the explosive mating crowds, the "endurance" race, the cognitive bases of the "choosy" male and his immune defense. Social insect males are not just simple-minded mating machines, they are shaped, constrained and perhaps trapped by sexual selection. PMID:25280909

Beani, Laura; Dessì-Fulgheri, Francesco; Cappa, Federico; Toth, Amy

2014-10-01

127

A male-biased natal sex-ratio in inbred collared lemmings, Dicrostonyx groenlandicus.  

PubMed

A captive colony of collared lemmings (Dicrostonyx groenlandicus) from northern Alaska produced a male-biased sex ratio of 67% males for about three generations. These lemmings have a pair of autosomes fused to the sex chromosomes. Thus, males have two copies of some (formerly autosomal) sex-linked genes: One set is X-linked; the other can be described as Y-linked. Given such a karyotype, deleterious recessive alleles on the autosomal portion of the X chromosome are more resistant to selection than truly autosomal loci because they can be eliminated by homozygosity only in females. The male-bias could have resulted from one or more lethals carried on the formerly autosomal arm of the X chromosome. As inbreeding coefficients approached 0.3, the lethal was apparently homozygous in half of the homogametic (female) zygotes. This phenomenon may explain the excess of males and XY females attributed to meiotic drive in Dicrostonyx torquatus from Siberia. If under the natural mating system, inbreeding depression limits fitness, then fusion of autosomal chromatin to the sex chromosomes could be an adaptation to reduce inbreeding depression in heterogametic individuals. PMID:8598343

Jarrell, G H

1995-01-01

128

Behavioral evidence for the presence of a sex pheromone in male Phlebotomus papatasi scopoli (Diptera: Psychodidae).  

PubMed

Phlebotomus papatasi (Diptera: Psychodidae) is the Old World sand fly vector of zoonotic cutaneous leishmaniasis caused by Leishmania major (Trypanosomatidae: Kinetoplastida), a debilitating and disfiguring protist parasitic disease prevalent throughout southern Mediterranean countries, the Middle East, as well as southern and eastern European countries, where it is regarded as a serious public health problem. Little is known of the mating ecology of P. papatasi, and, in particular, the role (if any) of pheromones is not known. In this laboratory- and field-based study, we have shown that a male-produced sex pheromone exists in P. papatasi. Young female P. papatasi are attracted to the headspace volatiles of small groups of males, males and females together, but not females alone. Males were not attracted to males, females, or mixed groups of males and females in the laboratory. Larger groups of males or males and females together were repellent in the laboratory study. Field experiments showed that Centers for Disease Control (CDC) light traps baited with small groups of males and females together were attractive to females, but not males. CDC traps baited with large groups of males and females together caught significantly fewer females and males than the control traps; however, the proportion of females caught compared with males overall was much higher than with CDC traps baited with small numbers of males and females. These results suggest that females may be attracted in preference to males to the vicinity of the baited traps and are highly sensitive to the concentration of male pheromone. It also suggests that P. papatasi mating behavior is fundamentally different from that of Lutzomyia longipalpis, where large mating aggregations of males and females occur. PMID:21661311

Chelbi, I; Zhioua, E; Hamilton, J G C

2011-05-01

129

Bile Acid Secreted by Male Sea Lamprey That Acts as a Sex Pheromone  

Microsoft Academic Search

We show that reproductively mature male sea lampreys release a bile acid that acts as a potent sex pheromone, inducing preference and searching behavior in ovulated female lampreys. The secreted bile acid 7alpha,12alpha,24-trihydroxy-5alpha-cholan-3-one 24-sulfate was released in much higher amounts relative to known vertebrate steroid pheromones and may be secreted through the gills. Hence, the male of this fish species

Weiming Li; Alexander P. Scott; Michael J. Siefkes; Honggao Yan; Qin Liu; Sang-Seon Yun; Douglas A. Gage

2002-01-01

130

HIV prevention needs among street-based male sex workers in Providence, Rhode Island.  

PubMed

We examined data derived from a needs assessment of the personal and social characteristics and HIV risk behavior of street-based male sex workers, in Providence, Rhode Island, who engage in transactional sexual intercourse with other men. Substance use, injected drugs, needle sharing, and psychosocial distress were highly prevalent among the sample. History of physical, sexual, and emotional abuse was associated with increased risk of condomless anal sexual intercourse with paying male clients. PMID:25211761

Landers, Stewart; Closson, Elizabeth F; Oldenburg, Catherine E; Holcomb, Richard; Spurlock, Shannon; Mimiaga, Matthew J

2014-11-01

131

Male-specific suppression of hepatic microsomal UDP-glucuronosyl transferase activities toward sex hormones in the adult male rat administered bisphenol A.  

PubMed Central

Various adverse effects of endocrine disruptors on the reproductive organs of male animals have been reported. We found that UDP-glucuronosyltransferase (UGT) activities towards bisphenol A, testosterone and oestradiol were significantly decreased in liver microsomes prepared from adult male Wistar rats administered with the endocrine disruptor bisphenol A (1 mg/2 days for 2 or 4 weeks). However, suppression of the transferase activities was not observed in female rats, even after bisphenol A treatment for 4 weeks. Diethylstilbestrol, which is well known as an endocrine disruptor, had the same effects, but p -cumylphenol had no effect on UGT activities towards sex hormones. Co-administration of an anti-oestrogen, tamoxifen, inhibited the suppression of the transferase activities by bisphenol A. Western blotting analysis showed that the amount of UGT2B1, an isoform of UGT which glucuronidates bisphenol A, was decreased in the rat liver microsomes by the treatment. Northern blotting analysis also indicated that UGT2B1 mRNA in the liver was decreased by bisphenol A treatment. The suppression of UGT activities, UGT2B1 protein and UGT2B1 mRNA expression did not occur in female rats. The results indicate that bisphenol A treatment reduces the mRNA expression of UGT2B1 and other UGT isoforms that mediate the glucuronidation of sex hormones in adult male rats, and this suggests that the endocrine balance may be disrupted by suppression of glucuronidation. PMID:12230427

Shibata, Noriaki; Matsumoto, Junya; Nakada, Ken; Yuasa, Akira; Yokota, Hiroshi

2002-01-01

132

Do sex-changing male snails use mate choice to get a jump on their “size advantage”?  

Microsoft Academic Search

Individuals of species that change sex from male to female may gain a “size advantage” from that sex change; that is, as males\\u000a become larger, they become female, thus increasing their fecundity with their size. However, males could also gain an early\\u000a and different reproductive size advantage by choosing large females as mates. While male preference for large females has

Olivia V. Ambrogio; Jan A. Pechenik

2009-01-01

133

Strategies for Recruiting Steady Male Partners of Female Sex Workers for HIV Research.  

PubMed

Steady male partners of female sex workers (FSW) are a key population for HIV prevention, but researchers face challenges finding and recruiting this population. We conducted 40 in-depth interviews with FSW and steady male partners of FSW in Santo Domingo, Dominican Republic about how to engage steady male partners in HIV research. Participants cautioned that male partners might be unwilling to participate because of discomfort disclosing intimate information and cultural norms of masculinity. They recommended inviting male partners to research offices, instead of venue-based recruitment, because it was more private and trust-promoting. Most participants suggested that FSW could refer their partners or men could refer their friends who have FSW partners. Participants emphasized that referrals could break down trust-related barriers that prevent male partners from participating. Establishing an environment of respect and trust in the research setting can aid referral processes as individuals who participate communicate their positive experiences to their networks. PMID:25192901

Fleming, Paul J; Barrington, Clare; Perez, Martha; Donastorg, Yeycy; Kerrigan, Deanna

2015-02-01

134

Evidence for a male-produced sex pheromone in the western flower thrips Frankliniella occidentalis.  

PubMed

Olfactometer bioassays of walking adult western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) showed that virgin females (1- to 3-d postemergence) were attracted to the odor of 25 adult males, but not to the odor of 25 adult females, providing behavioral evidence for a male-produced sex pheromone in this species. In contrast to earlier findings, mixed-age adult males were attracted to the odor of adult males. GC analysis of odors collected on SPME fibers revealed two major components and five minor components that were present in the male odor and not in the female odor. The compounds were not present in hexane extracts of males, indicating that these compounds are produced on demand and not stored. PMID:15074664

Kirk, William D J; Hamilton, James G C

2004-01-01

135

The Sexual Abuse of Boys in Organized Male Sports  

Microsoft Academic Search

Childhood sexual abuse (CSA) is now a significant issue for organized sports. Since its “discovery” thirty years ago, research on CSA has been guided mostly by the “maleperpetrator—female victim” paradigm; hence, the perspective of the sexually abused male in the sports context has rarely been considered. This article considers organized male-sports as a social space that facilitates the sexual abuse

Mike Hartill

2009-01-01

136

Aggressive behavior of the male parent predicts brood sex ratio in a songbird  

NASA Astrophysics Data System (ADS)

Brood sex ratio is often affected by parental or environmental quality, presumably in an adaptive manner that is the sex that confers higher fitness benefits to the mother is overproduced. So far, studies on the role of parental quality have focused on parental morphology and attractiveness. However, another aspect, the partner's behavioral characteristics, may also be expected to play a role in brood sex ratio adjustment. To test this hypothesis, we investigated whether the proportion of sons in the brood is predicted by the level of territorial aggression displayed by the father, in the collared flycatcher ( Ficedula albicollis). The proportion of sons in the brood was higher in early broods and increased with paternal tarsus length. When controlling for breeding date and body size, we found a higher proportion of sons in the brood of less aggressive fathers. Male nestlings are more sensitive to the rearing environment, and the behavior of courting males may often be used by females to assess their future parental activity. Therefore, adjusting brood sex ratio to the level of male aggression could be adaptive. Our results indicate that the behavior of the partner could indeed be a significant determinant in brood sex ratio adjustment, which should not be overlooked in future studies.

Szász, Eszter; Garamszegi, László Zsolt; Hegyi, Gergely; Szöll?si, Eszter; Markó, Gábor; Török, János; Rosivall, Balázs

2014-08-01

137

Aggressive behavior of the male parent predicts brood sex ratio in a songbird.  

PubMed

Brood sex ratio is often affected by parental or environmental quality, presumably in an adaptive manner that is the sex that confers higher fitness benefits to the mother is overproduced. So far, studies on the role of parental quality have focused on parental morphology and attractiveness. However, another aspect, the partner's behavioral characteristics, may also be expected to play a role in brood sex ratio adjustment. To test this hypothesis, we investigated whether the proportion of sons in the brood is predicted by the level of territorial aggression displayed by the father, in the collared flycatcher (Ficedula albicollis). The proportion of sons in the brood was higher in early broods and increased with paternal tarsus length. When controlling for breeding date and body size, we found a higher proportion of sons in the brood of less aggressive fathers. Male nestlings are more sensitive to the rearing environment, and the behavior of courting males may often be used by females to assess their future parental activity. Therefore, adjusting brood sex ratio to the level of male aggression could be adaptive. Our results indicate that the behavior of the partner could indeed be a significant determinant in brood sex ratio adjustment, which should not be overlooked in future studies. PMID:24973871

Szász, Eszter; Garamszegi, László Zsolt; Hegyi, Gergely; Szöll?si, Eszter; Markó, Gábor; Török, János; Rosivall, Balázs

2014-08-01

138

The role of sexually explicit material in the sexual development of same-sex-attracted black adolescent males.  

PubMed

Sexually explicit material (SEM) (including Internet, video, and print) may play a key role in the lives of Black same-sex sexually active youth by providing the only information to learn about sexual development. There is limited school- and/or family-based sex education to serve as models for sexual behaviors for Black youth. We describe the role SEM plays in the sexual development of a sample of Black same-sex attracted (SSA) young adolescent males ages 15-19. Adolescents recruited from clinics, social networking sites, and through snowball sampling were invited to participate in a 90-min, semi-structured qualitative interview. Most participants described using SEM prior to their first same-sex sexual experience. Participants described using SEM primarily for sexual development, including learning about sexual organs and function, the mechanics of same-gender sex, and to negotiate one's sexual identity. Secondary functions were to determine readiness for sex; to learn about sexual performance, including understanding sexual roles and responsibilities (e.g., "top" or "bottom"); to introduce sexual performance scripts; and to develop models for how sex should feel (e.g., pleasure and pain). Youth also described engaging in sexual behaviors (including condom non-use and/or swallowing ejaculate) that were modeled on SEM. Comprehensive sexuality education programs should be designed to address the unmet needs of young, Black SSA men, with explicit focus on sexual roles and behaviors that may be inaccurately portrayed and/or involve sexual risk-taking (such as unprotected anal intercourse and swallowing ejaculate) in SEM. This work also calls for development of Internet-based HIV/STI prevention strategies targeting young Black SSA men who may be accessing SEM. PMID:25677334

Arrington-Sanders, Renata; Harper, Gary W; Morgan, Anthony; Ogunbajo, Adedotun; Trent, Maria; Fortenberry, J Dennis

2015-04-01

139

Sex differences in the functional organization of the brain for language  

Microsoft Academic Search

A much debated question is whether sex differences exist in the functional organization of the brain for language *RF 1-4*. A long-held hypothesis posits that language functions are more likely to be highly lateralized in males and to be represented in both cerebral hemispheres in females (5,6), but attempts to demonstrate this have been inconclusive (7- 17). Here we use

R. Todd Constable; Pawel Skudlarski; Robert K. Fulbright; Richard A. Bronen; Jack M. Fletcher; Donald P. Shankweiler; Leonard Katz; John C. Gore

1995-01-01

140

Sex differences and social organization in free-ranging spider monkeys ( Ateles geoffroyi )  

Microsoft Academic Search

Several aspects of the social system of spider monkeys remain poorly understood in spite of previous studies of their behavior.\\u000a Our work investigates sex differences of adultAteles geoffroyi to develop a better understanding of their social organization. A six-month field study of this species in Guatemala showed\\u000a that adult males were both more aggressive and more socially cohesive than females,

Linda Marie Fedigan; Margaret Joan Baxter

1984-01-01

141

Maternal control of offspring sex and male morphology in the Otitesella fig wasps  

Microsoft Academic Search

Models concerning the evolution of alternative mating tactics commonly assume that individuals determine their own strategies. Here we develop a computer-based ESS model that allows mothers, ovipositing in discrete patches, to choose both the sex and the male mating tactics (natal-patch mating or dispersing) of their offspring based only on how many other mothers have used the specific patch before

J. P IENAAR; J. M. GREEFF

2003-01-01

142

Surgical treatment of locally advanced anal cancer after male-to-female sex reassignment surgery  

PubMed Central

We present a case of a transsexual patient who underwent a partial pelvectomy and genital reconstruction for anal cancer after chemoradiation. This is the first case in literature reporting on the occurrence of anal cancer after male-to-female sex reassignment surgery. We describe the surgical approach presenting our technique to avoid postoperative complications and preserve the sexual reassignment. PMID:19533817

Caricato, Marco; Ausania, Fabio; Marangi, Giovanni Francesco; Cipollone, Ilaria; Flammia, Gerardo; Persichetti, Paolo; Trodella, Lucio; Coppola, Roberto

2009-01-01

143

MALE-BIASED SEX RATIOS IN LABORATORY REARINGS OF GYPSY MOTH PARASITOIDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Male-biased sex ratios in populations of parasitic wasps used in biological control are undesirable, because a low ratio of females can prevent the establishment of introduced species or hinder commercial production of species used for augmentative control. This problem has arisen in the culture of...

144

SEX PHEROMONE ACTIVITY OF THE MOLTING HORMONE, CRUSTECDYSONE, ON MALE CRABS  

E-print Network

SEX PHEROMONE ACTIVITY OF THE MOLTING HORMONE, CRUSTECDYSONE, ON MALE CRABS (Pa~hygrapsus ~rassipes' ABSTRACT The pheromone released by premolt female Pachygrapsu8 cras.~ipes is a heat stable non-ionic polar lipid. The coincidence of the release of the pheromone and the nubial molt suggested that the molting

145

Male Sex Roles and Epithets for Ethnic Women in American Slang.  

ERIC Educational Resources Information Center

Research shows that derogatory names used for women of ethnic outgroups (1) are aimed disproportionately at women of racial minorities; (2) stereotype physical differences between ethnic groups; (3) make derogatory sexual allusions, often using food and animal metaphors; and (4) display the strains of traditional male sex roles in ethnic and…

Allen, Irving Lewis

1984-01-01

146

Adolescent and Young Adult Male Sex Offenders: Understanding the Role of Recidivism  

ERIC Educational Resources Information Center

The current review explores the complex paths that can lead to adolescent and young adult males becoming sexually abusive. Because sexual abuse is an ongoing issue in our society that is often oversimplified, this article distinguishes between the various risk factors that predict sexually abusive behavior and types of sex offenders, particularly…

Riser, Diana K.; Pegram, Sheri E.; Farley, Julee P.

2013-01-01

147

Does Sex (Female versus Male) Influence the Impact of Class Attendance on Examination Performance?  

ERIC Educational Resources Information Center

The "conventional wisdom" is that grades are related to class attendance, i.e., students who attend classes more frequently obtain better grades and class attendance dramatically contributes to enhanced learning. However, the influence of sex (female vs. male) on this relationship is understudied. Furthermore, there have been several studies…

Cortright, Ronald N.; Lujan, Heidi L.; Cox, Julie H.; DiCarlo, Stephen E.

2011-01-01

148

OLFACTORY DISCRIMINATION OF SEX PHEROMONE STEREOISOMERS: CHIRALITY RECOGNITION BY PINK HIBISCUS MEALYBUG MALES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Our previous field studies suggested that the two chiral centers that existed in sex pheromone of pink hibiscus mealybug, Maconellicoccus hirsutus, could elicit different male attractive responses. The chiral center in the acidic moiety of the ester seemed to be more critical than the alcoholic por...

149

Sex-Based Differences in School Content and the Male-Female Wage Gap  

Microsoft Academic Search

In high school and college, men and women take significantly different courses. Using data from the Survey of Income and Program Participation and the National Longitudinal Study class of 1972, the authors relate these differences in school content to sex differences in adult wages. Differences in field of highest degree account for a significant part of the male-female wage gap

Charles Brown; Mary Corcoran

1997-01-01

150

Male-biased sex ratio in litters of Alpine marmots supports the helper repayment hypothesis  

Microsoft Academic Search

In a French population of Alpine marmots (Marmota marmota), the sex ratio at weaning was biased in favor of males. This bias also seemed to exist at birth. Under Fisher's equal allocation principle, this means that daughters should be more costly to produce than sons. Because the Alpine marmot can be considered a cooperative breeding species, we investigated whether the

Dominique Allaine; Francine Brondex; Laurent Graziani; Jacques Coulon; Irene Till-Bottraudb

2000-01-01

151

SEX RECOGNITION IN SURFACE AND CAVE DWELLING MALE ATLANTIC MOLLIES POECILIA MEXICANA  

E-print Network

SEX RECOGNITION IN SURFACE AND CAVE DWELLING MALE ATLANTIC MOLLIES POECILIA MEXICANA (POECILIIDAE to recognizefemales in two surface and a cave dwelling population of a livebearing sh, Poecilia mexicana. In surface in two surface and a cave dwelling popula- tion of Atlantic mollies. Poecilia mexicana is widely

Schlupp, Ingo

152

Sex-contingent face after-effects suggest distinct neural populations code male and female faces  

E-print Network

Sex-contingent face after-effects suggest distinct neural populations code male and female faces of Psychology, University of Aberdeen, Aberdeen AB24 2UB, UK Exposure to faces biases perceptions of subsequently viewed faces. Faces similar to those seen previously are judged more normal and attractive than

Little, Tony

153

Identification of a Sex Attractant Pheromone for Male Winterform Pear Psylla, Cacopsylla pyricola  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pear psylla, Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae), a major economic pest of pears, have been shown to use a female-produced sex attractant pheromone. We compared the chemical profiles obtained from cuticular extracts of diapausing and post-diapause winterform males and females, with...

154

An exploration of elevated HIV and STI risk among male sex workers from India  

PubMed Central

Background Men who have sex with men (MSM) who also report transactional sex (male sex workers or MSWs) are known to be at higher risk for HIV and sexually transmitted infections (STIs). The study aimed to profile socio-demographic characteristics and risk factors associated with high HIV prevalence among MSWs. Methods A cross-sectional study was conducted in 2008–9 among 483 high-risk MSM who attended STI clinics at Mumbai and Hyderabad, two large cities in India. Results About 70% of the MSM reported transactional sex. As compared to other MSM, MSWs had more male partners (8.9 versus 2.5, p?sex (96% versus 72%, p?sex work (increased by 8% for every additional year). Conclusion The study showed that MSWs are at high risk for HIV acquisition/transmission, which highlights the need for intensified interventions for personalized risk-reduction counselling and STI screening. Newer biomedical interventions such as pre-exposure prophylaxis and treatment as prevention could also be considered. PMID:24209579

2013-01-01

155

Adverse Childhood Experiences in the Lives of Male Sex Offenders: Implications for Trauma-Informed Care.  

PubMed

This study explored the prevalence of childhood trauma in a sample of male sexual offenders (N = 679) using the Adverse Childhood Experience (ACE) scale. Compared with males in the general population, sex offenders had more than 3 times the odds of child sexual abuse (CSA), nearly twice the odds of physical abuse, 13 times the odds of verbal abuse, and more than 4 times the odds of emotional neglect and coming from a broken home. Less than 16% endorsed zero ACEs and nearly half endorsed four or more. Multiple maltreatments often co-occurred with other types of household dysfunction, suggesting that many sex offenders were raised within a disordered social environment. Higher ACE scores were associated with higher risk scores. By enhancing our understanding of the frequency and correlates of early adverse experiences, we can better devise trauma-informed interventions that respond to the clinical needs of sex offender clients. PMID:24872347

Levenson, Jill S; Willis, Gwenda M; Prescott, David S

2014-05-28

156

Fluorochemicals used in food packaging inhibit male sex hormone synthesis.  

PubMed

Polyfluoroalkyl phosphate surfactants (PAPS) are widely used in food contact materials (FCMs) of paper and board and have recently been detected in 57% of investigated materials. Human exposure occurs as PAPS have been measured in blood; however knowledge is lacking on the toxicology of PAPS. The aim of this study was to elucidate the effects of six fluorochemicals on sex hormone synthesis and androgen receptor (AR) activation in vitro. Four PAPS and two metabolites, perfluorooctanoic acid (PFOA) and 8:2 fluorotelomer alcohol (8:2 FTOH) were tested. Hormone profiles, including eight steroid hormones, generally showed that 8:2 diPAPS, 8:2 monoPAPS and 8:2 FTOH led to decreases in androgens (testosterone, dehydroepiandrosterone, and androstenedione) in the H295R steroidogenesis assay. Decreases were observed for progesterone and 17-OH-progesterone as well. These observations indicated that a step prior to progestagen and androgen synthesis had been affected. Gene expression analysis of StAR, Bzrp, CYP11A, CYP17, CYP21 and CYP19 mRNA showed a decrease in Bzrp mRNA levels for 8:2 monoPAPS and 8:2 FTOH indicating interference with cholesterol transport to the inner mitochondria. Cortisol, estrone and 17?-estradiol levels were in several cases increased with exposure. In accordance with these data CYP19 gene expression increased with 8:2 diPAPS, 8:2 monoPAPS and 8:2 FTOH exposures indicating that this is a contributing factor to the decreased androgen and the increased estrogen levels. Overall, these results demonstrate that fluorochemicals present in food packaging materials and their metabolites can affect steroidogenesis through decreased Bzrp and increased CYP19 gene expression leading to lower androgen and higher estrogen levels. PMID:23142464

Rosenmai, A K; Nielsen, F K; Pedersen, M; Hadrup, N; Trier, X; Christensen, J H; Vinggaard, A M

2013-01-01

157

Masculine Epigenetic Sex Marks of the CYP19A1/Aromatase Promoter in Genetically Male Chicken Embryonic Gonads Are Resistant to Estrogen-Induced Phenotypic Sex Conversion1  

PubMed Central

ABSTRACT Sex of birds is genetically determined through inheritance of the ZW sex chromosomes (ZZ males and ZW females). Although the mechanisms of avian sex determination remains unknown, the genetic sex is experimentally reversible by in ovo exposure to exogenous estrogens (ZZ-male feminization) or aromatase inhibitors (ZW-female masculinization). Expression of various testis- and ovary-specific marker genes during the normal and reversed gonadal sex differentiation in chicken embryos has been extensively studied, but the roles of sex-specific epigenetic marks in sex differentiation are unknown. In this study, we show that a 170-nt region in the promoter of CYP19A1/aromatase, a key gene required for ovarian estrogen biosynthesis and feminization of chicken embryonic gonads, contains highly quantitative, nucleotide base-level epigenetic marks that reflect phenotypic gonadal sex differentiation. We developed a protocol to feminize ZZ-male chicken embryonic gonads in a highly quantitative manner by direct injection of emulsified ethynylestradiol into yolk at various developmental stages. Taking advantage of this experimental sex reversal model, we show that the epigenetic sex marks in the CYP19A1/aromatase promoter involving DNA methylation and histone lysine methylation are feminized significantly but only partially in sex-converted gonads even when morphological and transcriptional marks of sex differentiation show complete feminization, being indistinguishable from gonads of normal ZW females. Our study suggests that the epigenetic sex of chicken embryonic gonads is more stable than the morphologically or transcriptionally characterized sex differentiation, suggesting the importance of the nucleotide base-level epigenetic sex in gonadal sex differentiation. PMID:22539680

Ellis, Haley L.; Shioda, Keiko; Rosenthal, Noël F.; Coser, Kathryn R.; Shioda, Toshi

2012-01-01

158

Masculine epigenetic sex marks of the CYP19A1/aromatase promoter in genetically male chicken embryonic gonads are resistant to estrogen-induced phenotypic sex conversion.  

PubMed

Sex of birds is genetically determined through inheritance of the ZW sex chromosomes (ZZ males and ZW females). Although the mechanisms of avian sex determination remains unknown, the genetic sex is experimentally reversible by in ovo exposure to exogenous estrogens (ZZ-male feminization) or aromatase inhibitors (ZW-female masculinization). Expression of various testis- and ovary-specific marker genes during the normal and reversed gonadal sex differentiation in chicken embryos has been extensively studied, but the roles of sex-specific epigenetic marks in sex differentiation are unknown. In this study, we show that a 170-nt region in the promoter of CYP19A1/aromatase, a key gene required for ovarian estrogen biosynthesis and feminization of chicken embryonic gonads, contains highly quantitative, nucleotide base-level epigenetic marks that reflect phenotypic gonadal sex differentiation. We developed a protocol to feminize ZZ-male chicken embryonic gonads in a highly quantitative manner by direct injection of emulsified ethynylestradiol into yolk at various developmental stages. Taking advantage of this experimental sex reversal model, we show that the epigenetic sex marks in the CYP19A1/aromatase promoter involving DNA methylation and histone lysine methylation are feminized significantly but only partially in sex-converted gonads even when morphological and transcriptional marks of sex differentiation show complete feminization, being indistinguishable from gonads of normal ZW females. Our study suggests that the epigenetic sex of chicken embryonic gonads is more stable than the morphologically or transcriptionally characterized sex differentiation, suggesting the importance of the nucleotide base-level epigenetic sex in gonadal sex differentiation. PMID:22539680

Ellis, Haley L; Shioda, Keiko; Rosenthal, Noël F; Coser, Kathryn R; Shioda, Toshi

2012-07-01

159

Low male-to-female sex ratio of children born in India: national survey of 1·1 million households  

Microsoft Academic Search

Findings For the 133 738 births studied for 1997, the adjusted sex ratio for the second birth when the preceding child was a girl was 759 per 1000 males (99% CI 731-787). The adjusted sex ratio for the third child was 719 (675-762) if the previous two children were girls. By contrast, adjusted sex ratios for second or third births

Prabhat Jha; Rajesh Kumar; Priya Vasa; Neeraj Dhingra; Deva Thiruchelvam; Rahim Moineddin

2006-01-01

160

Sex differences in the genetic architecture of lifespan in a seed beetle: extreme inbreeding extends male lifespan  

Microsoft Academic Search

BACKGROUND: Sex differences in lifespan are ubiquitous throughout the animal kingdom but the causes underlying this phenomenon remain poorly understood. Several explanations based on asymmetrical inheritance patterns (sex chromosomes or mitochondrial DNA) have been proposed, but these ideas have rarely been tested experimentally. Alternatively, sexual dimorphism in lifespan could result from sex-specific selection, caused by fundamental differences in how males

Trine Bilde; Alexei A Maklakov; Katrine Meisner; Lucia la Guardia; Urban Friberg

2009-01-01

161

Functionally reproductive diploid and haploid males in an inbreeding hymenopteran with complementary sex determination  

PubMed Central

It has become a matter of orthodoxy that among wasps, ants, bees, and other insects in the order Hymenoptera, only uniparental haploid males that arise from unfertilized eggs are capable of reproduction. This idea is of interest because the best understood and perhaps most widespread sex determination system among these insects [known as single locus complementary sex determination (sl-CSD)] does not depend on ploidy alone and, paradoxically, consistently results in small numbers of diploid biparental males. To date, the reproductive potential of diploid males has been studied in 13 of the perhaps 200,000 hymenopterans world-wide; in each of these instances, the diploid males are genetic dead ends because they are inviable or sterile. The data from these species have resulted in a general conclusion that has been invoked for virtually all species with sl-CSD and has become the basis for assumptions regarding conservation biology, sex ratio analysis, and the evolution of social behavior. Here, we report that in the solitary vespid wasp Euodynerus foraminatus, both diploid and haploid males are fertile, which documents normal fertility in diploid males of a hymenopteran with sl-CSD. This wasp has high levels of inbreeding because of frequent brother–sister mating in nature; therefore, diploid males are more frequently produced and thus more likely exposed to selection favoring their fertility. Because inbreeding and diploid male production may be important features of the population biology of many hymenopterans, we sound a cautionary note regarding ideas about the evolutionary ecology of these insects. PMID:15232002

Cowan, David P.; Stahlhut, Julie K.

2004-01-01

162

Developmental effects of an environmental antiandrogen: the fungicide vinclozolin alters sex differentiation of the male rat.  

PubMed

In humans and rodents, exposure to hormonally active chemicals during sex differentiation can produce a wide range of abnormal sexual phenotypes including masculinized and defeminized females and feminized and demasculinized males. Although numerous "environmental estrogens," including pesticides, toxic substances (PCBs), and plant and fungal estrogens, have been shown to alter mammalian sex differentiation, similar information on environmental androgens is lacking. Recently, the fungicide vinclozolin (V) was found to inhibit sexual differentiation in male rats in an antiandrogenic manner. In the present study, V was administered to pregnant rats (p.o.) at 0, 100, or 200 mg/kg/day in corn oil during the period of sex differentiation (Gestational Day 14 to Postnatal Day 3) to examine the demasculinizing effect of this fungicide more closely. In both groups of V-treated male offspring, anogenital distance was female like at birth, and nipple development was prominent at 2 weeks of age. After puberty, most of the V-treated male offspring were unable to attain intromission even though they all mounted sexually receptive females. The V-treated male offspring that appeared to achieve intromission, failed to ejaculate normally, as no sperm were found in the uterus after overnight matings. A factor in the abnormal ejaculation was that all V-treated male offspring had cleft phallus with hypospadias. In addition, a number of unusual reproductive malformations were noted when the males were necropsied at 1 year. Many V-treated male offspring had suprainguinal ectopic scrota/testes, a vaginal pouch, epididymal granulomas, and small to absent sex accessory glands. During the study, about 25% of the V-treated males died as a result of bladder stones, hydroureter, or hydronephrosis, while other males displayed these lesions at necropsy. While some of the above malformations in male offspring can also be produced by perinatal administration of a potent estrogen, like DES, V-treated female offspring did not display any estrogen-like alterations of reproductive development or fecundity. The only change seen in the female offspring was a reduced anogenital distance during neonatal life. Our observation of perinatal-induced agenesis of the prostate and blocked testicular descent, a pattern of malformations nearly identical to that reported for the antiandrogen flutamide, is consistent with other recent evidence that this fungicide is an androgen-receptor antagonist. PMID:7974495

Gray, L E; Ostby, J S; Kelce, W R

1994-11-01

163

Homeoproteins Six1 and Six4 regulate male sex determination and mouse gonadal development.  

PubMed

The Y-linked gene Sry regulates mammalian sex determination in bipotential embryonic gonads. Here, we report that the transcription factors Six1 and Six4 are required for male gonadal differentiation. Loss of Six1 and Six4 together, but neither alone, resulted in a male-to-female sex-reversal phenotype in XY mutant gonads accompanied by a failure in Sry activation. Decreased gonadal precursor cell formation at the onset of Sry expression and a gonadal size reduction in both sexes were also found in mutant embryos. Forced Sry transgene expression in XY mutant gonads rescued testicular development but not the initial disruption to precursor growth. Furthermore, we identified two downstream targets of Six1/Six4 in gonadal development, Fog2 (Zfpm2) and Nr5a1 (Ad4BP/Sf1). These two distinct Six1/Six4-regulated pathways are considered to be crucial for gonadal development. The regulation of Fog2 induces Sry expression in male sex determination, and the regulation of Nr5a1 in gonadal precursor formation determines gonadal size. PMID:23987514

Fujimoto, Yuka; Tanaka, Satomi S; Yamaguchi, Yasuka L; Kobayashi, Hiroki; Kuroki, Shunsuke; Tachibana, Makoto; Shinomura, Mai; Kanai, Yoshiakira; Morohashi, Ken-Ichirou; Kawakami, Kiyoshi; Nishinakamura, Ryuichi

2013-08-26

164

Environmental conditions affect sex expression in monoecious, but not in male and female plants of Urtica dioica  

Microsoft Academic Search

Urtica dioica is a sub-dioecious plant species, i.e. males and females coexist with monoecious individuals. Under standard conditions, seed sex ratio (SSR, fraction of males) was found to vary significantly among seed samples collected from female plants originating from the same population (0.05–0.76). As a first step, we investigated the extent to which SSR and sex expression of male, female,

Grit A. Glawe; Tom J. de Jong

2005-01-01

165

Molecular diagnostic testing for Klinefelter syndrome and other male sex chromosome aneuploidies  

PubMed Central

Background Male sex chromosome aneuploidies are underdiagnosed despite concomitant physical and behavioral manifestations. Objective To develop a non-invasive, rapid and high-throughput molecular diagnostic assay for detection of male sex chromosome aneuploidies, including 47,XXY (Klinefelter), 47,XYY, 48,XXYY and 48,XXXY syndromes. Methods The assay utilizes three XYM and four XA markers to interrogate Y:X and X:autosome ratios, respectively. The seven markers were PCR amplified using genomic DNA isolated from a cohort of 323 males with aneuploid (n?=?117) and 46,XY (n?=?206) karyotypes. The resulting PCR products were subjected to Pyrosequencing, a quantitative DNA sequencing method. Results Receiver operator characteristic (ROC) curves were used to establish thresholds for the discrimination of aneuploid from normal samples. The XYM markers permitted the identification of 47,XXY, 48,XXXY and 47,XYY syndromes with 100% sensitivity and specificity in both purified DNA and buccal swab samples. The 48,XXYY karyotype was delineated by XA marker data from 46,XY; an X allele threshold of 43% also permitted detection of 48,XXYY with 100% sensitivity and specificity. Analysis of X chromosome-specific biallelic SNPs demonstrated that 43 of 45 individuals (96%) with 48,XXYY karyotype had two distinct X chromosomes, while 2 (4%) had a duplicate X, providing evidence that 48,XXYY may result from nondisjunction during early mitotic divisions of a 46,XY embryo. Conclusions Quantitative Pyrosequencing, with high-throughput potential, can detect male sex chromosome aneuploidies with 100% sensitivity. PMID:22524164

2012-01-01

166

Sex disparity in colonic adenomagenesis involves promotion by male hormones, not protection by female hormones  

PubMed Central

It recently has been recognized that men develop colonic adenomas and carcinomas at an earlier age and at a higher rate than women. In the ApcPirc/+ (Pirc) rat model of early colonic cancer, this sex susceptibility was recapitulated, with male Pirc rats developing twice as many adenomas as females. Analysis of large datasets revealed that the ApcMin/+ mouse also shows enhanced male susceptibility to adenomagenesis, but only in the colon. In addition, WT mice treated with injections of the carcinogen azoxymethane (AOM) showed increased numbers of colonic adenomas in males. The mechanism underlying these observations was investigated by manipulation of hormonal status. The preponderance of colonic adenomas in the Pirc rat model allowed a statistically significant investigation in vivo of the mechanism of sex hormone action on the development of colonic adenomas. Females depleted of endogenous hormones by ovariectomy did not exhibit a change in prevalence of adenomas, nor was any effect observed with replacement of one or a combination of female hormones. In contrast, depletion of male hormones by orchidectomy (castration) markedly protected the Pirc rat from adenoma development, whereas supplementation with testosterone reversed that effect. These observations were recapitulated in the AOM mouse model. Androgen receptor was undetectable in the colon or adenomas, making it likely that testosterone acts indirectly on the tumor lineage. Our findings suggest that indirect tumor-promoting effects of testosterone likely explain the disparity between the sexes in the development of colonic adenomas. PMID:25368192

Amos-Landgraf, James M.; Heijmans, Jarom; Wielenga, Mattheus C. B.; Dunkin, Elisa; Krentz, Kathy J.; Clipson, Linda; Ederveen, Antwan G.; Groothuis, Patrick G.; Mosselman, Sietse; Muncan, Vanesa; Hommes, Daniel W.; Shedlovsky, Alexandra; Dove, William F.; van den Brink, Gijs R.

2014-01-01

167

Hombre Seguro (Safe Men): a sexual risk reduction intervention for male clients of female sex workers  

PubMed Central

Background Male clients of female sex workers (FSWs) are at risk of HIV and other sexually transmitted infections (STIs). We conducted a two-arm randomized controlled trial to test the efficacy of a sexual risk reduction intervention for male clients of FSWs in Tijuana, Mexico. Methods/Design Male clients of FSWs who were at least 18, were HIV-negative at baseline, and reported recent unprotected sex with FSWs were randomized to the Hombre Seguro sexual risk reduction intervention, or a time-attention didactic control condition. Each condition lasted approximately one hour. Participants underwent interviewer-administered surveys and testing for HIV and other STIs at baseline, and at 4, 8, and 12 month follow-ups. Combined HIV/STI incidence and unprotected vaginal and anal sex acts with FSWs were the primary outcomes. Discussion A total of 400 participants were randomized to one of the two conditions. Analyses indicated that randomization was successful; there were no significant differences between the participants in the two conditions at baseline. Average follow-up was 84% across both conditions. This is the first study to test the efficacy of a sexual risk reduction intervention for male clients of FSWs using the rigor of a randomized controlled trial. Trial registration NCT01280838, Date of registration: January 19, 2011. PMID:24885949

2014-01-01

168

HIV and STI prevalence and risk factors among male sex workers and other men who have sex with men in Nairobi, Kenya.  

PubMed

: Previous surveys of men who have sex with men (MSM) in Africa have not adequately profiled HIV status and risk factors by sex work status. MSM in Nairobi, Kenya, were recruited using respondent-driven sampling, completed a behavioral interview, and were tested for HIV and sexually transmitted infections. Overlapping recruitment among 273 male sex workers and 290 other MSM was common. Sex workers were more likely to report receptive anal sex with multiple partners (65.7% versus 18.0%, P < 0.001) and unprotected receptive anal intercourse (40.0% versus 22.8%, P = 0.005). Male sex workers were also more likely to be HIV infected (26.3% versus 12.2%, P = 0.007). PMID:25501346

Muraguri, Nicholas; Tun, Waimar; Okal, Jerry; Broz, Dita; Raymond, H Fisher; Kellogg, Timothy; Dadabhai, Sufia; Musyoki, Helgar; Sheehy, Meredith; Kuria, David; Kaiser, Reinhard; Geibel, Scott

2015-01-01

169

Sex, symptom, and premorbid social functioning associated with perceptual organization dysfunction in schizophrenia  

PubMed Central

Impairments in visual perceptual organization abilities are a repeatedly observed cognitive deficit in schizophrenia. These impairments have been found to be most prominent among patients with histories of poor premorbid social functioning, disorganized symptoms, and poor clinical outcomes. Despite the demonstration of significant sex differences for these clinical factors in schizophrenia, the extent of sex differences for visual perceptual organization in schizophrenia is unknown. Therefore, we investigated the extent to which previously known correlates (premorbid social sexual functioning and disorganized symptoms) and a novel factor (participant sex) accounted for performance on two perceptual organization tasks (contour integration and Ebbinghaus illusion) that have previously demonstrated sensitivity to schizophrenia. We also determined the relative degree to which each of these factors predicted task scores over and above the others. Schizophrenia patients (N = 109, 43 females) from different levels of care were ascertained. Female patients demonstrated higher contour integration scores, but lower performance on the context sensitivity index of the Ebbinghaus illusion, compared to males. Contour integration performance was significantly associated with poorer premorbid adolescent social sexual functioning and higher levels of disorganized symptoms, supporting past results that indicate a relationship among poor premorbid social sexual functioning, disorganized symptoms, and visual perceptual abnormalities in schizophrenia. However, analyses of Ebbinghaus illusion performance suggests there is a complex relationship among patient sex, clinical factors and perceptual abilities with relatively intact bottom–up grouping processes in females, but greater problems, compared to males with more top–down mediated context sensitivity. Therefore, sex differences may be an important consideration for future studies of visual perceptual organization in schizophrenia. PMID:23986732

Joseph, Jamie; Bae, Grace; Silverstein, Steven M.

2013-01-01

170

Male-biased distribution of the human Y chromosomal genes SRY and ZFY in the lizard Calotes versicolor , which lacks sex chromosomes and temperature-dependent sex determination  

Microsoft Academic Search

In the present investigation on the lizard Calotes versicolor, which lacks temperature-dependent sex determination, all the conventional cytological techniques used failed to resolve a distinguishable pair of sex chromosomes. However, probing of the genome with the human Y-linked genes SRY and ZFY showed sex-specific bias in their distribution. While the SRY probe hybridized to all the males, more than half

Subramaniam Ganesh; Jayashree Mohanty; Rajiva Raman

1997-01-01

171

Gene organization of the liverwort Y chromosome reveals distinct sex chromosome evolution in a haploid system.  

PubMed

Y chromosomes are different from other chromosomes because of a lack of recombination. Until now, complete sequence information of Y chromosomes has been available only for some primates, although considerable information is available for other organisms, e.g., several species of Drosophila. Here, we report the gene organization of the Y chromosome in the dioecious liverwort Marchantia polymorpha and provide a detailed view of a Y chromosome in a haploid organism. On the 10-Mb Y chromosome, 64 genes are identified, 14 of which are detected only in the male genome and are expressed in reproductive organs but not in vegetative thalli, suggesting their participation in male reproductive functions. Another 40 genes on the Y chromosome are expressed in thalli and male sexual organs. At least six of these genes have diverged X-linked counterparts that are in turn expressed in thalli and sexual organs in female plants, suggesting that these X- and Y-linked genes have essential cellular functions. These findings indicate that the Y and X chromosomes share the same ancestral autosome and support the prediction that in a haploid organism essential genes on sex chromosomes are more likely to persist than in a diploid organism. PMID:17395720

Yamato, Katsuyuki T; Ishizaki, Kimitsune; Fujisawa, Masaki; Okada, Sachiko; Nakayama, Shigeki; Fujishita, Mariko; Bando, Hiroki; Yodoya, Kohei; Hayashi, Kiwako; Bando, Tomoyuki; Hasumi, Akiko; Nishio, Tomohisa; Sakata, Ryoko; Yamamoto, Masayuki; Yamaki, Arata; Kajikawa, Masataka; Yamano, Takashi; Nishide, Taku; Choi, Seung-Hyuk; Shimizu-Ueda, Yuu; Hanajiri, Tsutomu; Sakaida, Megumi; Kono, Kaoru; Takenaka, Mizuki; Yamaoka, Shohei; Kuriyama, Chiaki; Kohzu, Yoshito; Nishida, Hiroyuki; Brennicke, Axel; Shin-i, Tadasu; Kohara, Yuji; Kohchi, Takayuki; Fukuzawa, Hideya; Ohyama, Kanji

2007-04-10

172

Relevance of Male-to-Female Sex Mismatch in Liver Transplantation for Primary Biliary Cirrhosis.  

PubMed

Background Because male-to-female transplantations are related to exposure to H-Y antigen, sex matching may influence the outcomes after liver transplantation for autoimmune diseases. The purpose of this retrospective study was to evaluate the relevance of male-to-female mismatch in liver transplantation for primary biliary cirrhosis (PBC). Material and Methods This retrospective study was based on the data of 82 female liver transplant recipients with PBC from a single institution. The primary outcome measure was graft survival at 10 years. The negative effects of well-known risk factors for poor outcomes were evaluated separately and compared between the female-to-female and male-to-female transplantations. Results Graft survival was similar after female-to-female and male-to-female transplantations (74.7% versus 73.1% at 10 years, respectively, p=0.676). Regarding the differential impact of other risk factors, prolonged cold ischemia and increased amount of blood transfusions adversely influenced outcomes after male-to-female transplantation (p=0.039 and p=0.039, respectively) but not after female-to-female transplantation (p=0.843 and p=0.110, respectively). Sex mismatched transplantations were associated with lower 10-year graft survival in subgroups of patients with blood transfusions >4 units (61.4% versus 100.0%, p=0.063) and >8 hours of cold ischemia (54.7% versus 75.8%, p=0.418). Conclusions Although male-to-female sex mismatch does not seem to yield a direct negative impact on outcomes following liver transplantation for PBC, it can aggravate the negative effects of prolonged cold ischemia and blood transfusions. PMID:25728977

Gr?t, Micha?; Lewandowski, Zbigniew; Patkowski, Waldemar; Wronka, Karolina Maria; Gr?t, Karolina; Krasnod?bski, Maciej; Ligocka, Joanna; Zborowska, Hanna; Krawczyk, Marek

2015-01-01

173

Female-Released Sex Pheromones Mediating Courtship Behavior in Lysiphlebus testaceipes Males  

PubMed Central

Ethological aspects and chemical communication at close-range between the sexes of Lysiphlebus testaceipes Cresson (Hymenoptera: Braconidae) have been investigated through behavioral bioassays and chemical analysis. The attractiveness toward males of whole-body extracts of females and males in hexane and acetone was evaluated, adopting male fanning behavior as a key behavioral component. Also, the activity of polar and nonpolar fraction of female-body extract in hexane obtained using solid-phase extraction technique was investigated. In order to identify cuticular compounds, male and female whole-body extracts with hexane and acetone were analyzed by gas chromatography-mass spectrometry. The results showed that males exhibit a behavior including 4 phases when exposed to virgin females: premount, mount, copulation, and post-copulation. A preliminary courtship of the male included wing fanning, an extension and vibration of the wings for 1 to 2 seconds. Also, some original aspects not described for other species were carried out. The average duration of the entire sequence of events was 138.80 ± 19.51 sec. Also, males displayed significantly more wing fanning behavior in response to female whole-body hexane extracts (70.83%) than female whole-body acetone extracts (33.3%). Furthermore, males did not respond to male-body extracts or to the control (pure hexane and acetone), suggesting that the sex pheromone is composed of cuticular hydrocarbons that are also involved in the male courtship behavior. When hexane extracts of whole females were fractionated on silica gel and exposed to males, more activity was recorded for the nonpolar fraction (50.0%) than the polar fraction (27.7%), but no significant statistical difference was found. Significant differences were detected comparing the control (not fractionated extract) with the polar fraction, but not with the nonpolar fraction. A homologous series of n-alkanes with chain lengths from C19 to C30 carbon atoms was identified and quantified in the solvent extracts of wasp males and females. Between male and female extracts, there was a statistically significant difference in the average quantity of some of these hydrocarbons, such as C27, C28, and C29. PMID:23906069

Lo Pinto, Mirella; Cangelosi, Benedetta; Colazza, Stefano

2013-01-01

174

Preventing HIV Transmission Among Partners of HIV-Positive Male Sex Workers in Mexico City: A Modeling Study.  

PubMed

Mexico has a concentrated HIV epidemic, with male sex workers constituting a key affected population. We estimated annual HIV cumulative incidence among male sex workers' partners, and then compared incidence under three hypothetical intervention scenarios: improving condom use; and scaling up HIV treatment as prevention, considering current viral suppression rates (CVS, 60.7 %) or full viral suppression among those treated (FVS, 100 %). Clinical and behavioral data to inform model parameterization were derived from a sample (n = 79) of male sex workers recruited from street locations and Clínica Condesa, an HIV clinic in Mexico City. We estimated annual HIV incidence among male sex workers' partners to be 8.0 % (95 % CI: 7.3-8.7). Simulation models demonstrated that increasing condom use by 10 %, and scaling up HIV treatment initiation by 50 % (from baseline values) would decrease the male sex workers-attributable annual incidence to 5.2, 4.4 % (CVS) and 3.2 % (FVS), respectively. Scaling up the number of male sex workers on ART and implementing interventions to ensure adherence is urgently required to decrease HIV incidence among male sex workers' partners in Mexico City. PMID:25307025

Monteiro, João Filipe G; Marshall, Brandon D L; Escudero, Daniel; Sosa-Rubí, Sandra G; González, Andrea; Flanigan, Timothy; Operario, Don; Mayer, Kenneth H; Lurie, Mark N; Galárraga, Omar

2014-10-12

175

Male territoriality and 'sex confusion' in recently adapted lizards at White Sands.  

PubMed

The evolution of intersexual interactions, like mate choice, during ecological speciation has received widespread attention. However, changes in intrasexual interactions, like male territoriality, during ecological divergence are largely unexamined. We conducted field experiments with adaptively diverged populations of the eastern fence lizard (Sceloporus undulatus) to determine whether territorial males behaved differently towards ecologically similar vs. dissimilar intruders. We performed trials with light-coloured males from White Sands, New Mexico and dark-coloured males from the surrounding desert. We found that intruders from White Sands elicited more aggression than intruders from dark-soil habitat. We also documented a case of 'sex confusion' where white-sand males courted dark-soil intruders. We found population differences in signalling patch size that can explain both aggression bias and sex misidentification. We argue that direct selection (for population recognition or optimal signal transmission) and indirect selection (by-products of ecological adaptation) should influence both intersexual and intrasexual interactions during ecological speciation. PMID:20695966

Robertson, J M; Rosenblum, E B

2010-09-01

176

Copyright 2004 by the Genetics Society of America Drosophila Male-Specific Lethal 2 Protein Controls Sex-Specific  

E-print Network

Controls Sex-Specific Expression of the roX Genes Barbara P. Rattner1 and Victoria H. Meller2 Department the transcriptional regulation of the roX genes and show that MSL2 controls male-specific roX expression chromosome, equalizing male and female X-linked gene expression. Five male-specific lethal proteins

Meller, Victoria

177

Selection on male sex pheromone composition contributes to butterfly reproductive isolation.  

PubMed

Selection can facilitate diversification by inducing character displacement in mate choice traits that reduce the probability of maladaptive mating between lineages. Although reproductive character displacement (RCD) has been demonstrated in two-taxa case studies, the frequency of this process in nature is still debated. Moreover, studies have focused primarily on visual and acoustic traits, despite the fact that chemical communication is probably the most common means of species recognition. Here, we showed in a large, mostly sympatric, butterfly genus, a strong pattern of recurrent RCD for predicted male sex pheromone composition, but not for visual mate choice traits. Our results suggest that RCD is not anecdotal, and that selection for divergence in male sex pheromone composition contributed to reproductive isolation within the Bicyclus genus. We propose that selection may target olfactory mate choice traits as a more common sensory modality to ensure reproductive isolation among diverging lineages than previously envisaged. PMID:25740889

Bacquet, P M B; Brattström, O; Wang, H-L; Allen, C E; Löfstedt, C; Brakefield, P M; Nieberding, C M

2015-04-01

178

Agency-Based Male Sex Work: A Descriptive Focus on Physical, Personal, and Social Space  

PubMed Central

Thirty male sex workers (MSWs) from a single agency participated in a qualitative interview about social and occupational aspects of their lives. MSWs established physical (defined areas where clients were not invited) and psychological (limitations of relationship with clients, other escorts, and the agency manager) boundaries to construct personal and professional space regarding sex work. Physical and psychological boundaries often were blended (e.g., bringing friends/family to the agency, utilizing the agency as a “drop-in community center”). The agency further mitigated negative aspects of sex work by providing job training, social support, stigma management, and dual-use space. Actors co-created a context wherein business could be conducted while meeting MSWs' psychosocial needs. PMID:19779572

Smith, Michael D.; Grov, Christian; Seal, David W.

2009-01-01

179

Regulation of the DNA damage response on male meiotic sex chromosomes.  

PubMed

During meiotic prophase in males, the sex chromosomes partially synapse to form the XY body, a unique structure that recruits proteins involved in the DNA damage response, which is believed to be important for silencing of the sex chromosomes. It remains elusive how the DNA damage response in the XY body is regulated. Here we show that H2AX-MDC1-RNF8 signaling, which is well characterized in somatic cells, is dispensable for the recruitment of proteins to the unsynapsed axes in the XY body. On the other hand, the DNA damage response that spreads over the sex chromosomes is largely similar to that in somatic cells. This analysis shows that there are important differences between the regulation of the DNA damage response at the XY body and at DNA damage sites in somatic cells. PMID:23812044

Lu, Lin-Yu; Xiong, Yi; Kuang, Henry; Korakavi, Gautam; Yu, Xiaochun

2013-01-01

180

Differential Recruitment and Control: The Sex Structuring of Organizations  

ERIC Educational Resources Information Center

Contends that sex differences in organizational participation are related to (1) differential recruitment of women into jobs requiring dependence and passivity; (2) selective recruitment of particularly compliant women into these jobs; and (3) control mechanisms used in organizations for women, which reinforce control mechanisms to which they are…

Acker, Joan; Van Houten, Donald R.

1974-01-01

181

Weed Killer Deforms Sex Organs in Frogs, Study Finds  

NSDL National Science Digital Library

This Web site discusses current research findings surrounding the use of the weed killer, atrazine, and sex organ deformities in frogs exposed to it. The article from the New York Times summarizes the recent research report; free registration is required to view it. This site reports focus on the potential impact of atrazine on humans, but they do raise it as an important question.

Associated Press.

182

Evolution of DMY, a newly emergent male sex-determination gene of medaka fish.  

PubMed Central

The Japanese medaka fish Oryzias latipes has an XX/XY sex-determination system. The Y-linked sex-determination gene DMY is a duplicate of the autosomal gene DMRT1, which encodes a DM-domain-containing transcriptional factor. DMY appears to have originated recently within Oryzias, allowing a detailed evolutionary study of the initial steps that led to the new gene and new sex-determination system. Here I analyze the publicly available DMRT1 and DMY gene sequences of Oryzias species and report the following findings. First, the synonymous substitution rate in DMY is 1.73 times that in DMRT1, consistent with the male-driven evolution hypothesis. Second, the ratio of the rate of nonsynonymous nucleotide substitution (d(N)) to that of synonymous substitution (d(S)) is significantly higher in DMY than in DMRT1. Third, in DMRT1, the d(N)/d(S) ratio for the DM domain is lower than that for non-DM regions, as expected from the functional importance of the DM domain. But in DMY, the opposite is observed and the DM domain is likely under positive Darwinian selection. Fourth, only one characteristic amino acid distinguishes all DMY sequences from all DMRT1 sequences, suggesting that a single amino acid change may be largely responsible for the establishment of DMY as the male sex-determination gene in medaka fish. PMID:15126406

Zhang, Jianzhi

2004-01-01

183

Sex Ratio Meiotic Drive as a Plausible Evolutionary Mechanism for Hybrid Male Sterility  

PubMed Central

Biological diversity on Earth depends on the multiplication of species or speciation, which is the evolution of reproductive isolation such as hybrid sterility between two new species. An unsolved puzzle is the exact mechanism(s) that causes two genomes to diverge from their common ancestor so that some divergent genes no longer function properly in the hybrids. Here we report genetic analyses of divergent genes controlling male fertility and sex ratio in two very young fruitfly species, Drosophila albomicans and D. nasuta. A majority of the genetic divergence for both traits is mapped to the same regions by quantitative trait loci mappings. With introgressions, six major loci are found to contribute to both traits. This genetic colocalization implicates that genes for hybrid male sterility have evolved primarily for controlling sex ratio. We propose that genetic conflicts over sex ratio may operate as a perpetual dynamo for genome divergence. This particular evolutionary mechanism may largely contribute to the rapid evolution of hybrid male sterility and the disproportionate enrichment of its underlying genes on the X chromosome – two patterns widely observed across animals. PMID:25822261

Zhang, Linbin; Xiao, Hailian; Tao, Yun

2015-01-01

184

No evidence for increased extinction proneness with decreasing effective population size in a parasitoid with complementary sex determination and fertile diploid males  

Microsoft Academic Search

BACKGROUND: In species with single locus complementary sex determination (sl-CSD), the sex of individuals depends on their genotype at one single locus with multiple alleles. Haploid individuals are always males. Diploid individuals are females when heterozygous, but males when homozygous at the sex-determining locus. Diploid males are typically unviable or effectively sterile, hence imposing a genetic load on populations. Diploid

Jan Elias; Silvia Dorn; Dominique Mazzi

2010-01-01

185

The costs of risky male behaviour: sex differences in seasonal survival in a small sexually monomorphic primate.  

PubMed

Male excess mortality is widespread among mammals and frequently interpreted as a cost of sexually selected traits that enhance male reproductive success. Sex differences in the propensity to engage in risky behaviours are often invoked to explain the sex gap in survival. Here, we aim to isolate and quantify the survival consequences of two potentially risky male behavioural strategies in a small sexually monomorphic primate, the grey mouse lemur Microcebus murinus: (i) most females hibernate during a large part of the austral winter, whereas most males remain active and (ii) during the brief annual mating season males roam widely in search of receptive females. Using a 10-year capture-mark-recapture dataset from a population of M. murinus in Kirindy Forest, western Madagascar, we statistically modelled sex-specific seasonal survival probabilities. Surprisingly, we did not find any evidence for direct survival benefits of hibernation-winter survival did not differ between males and females. By contrast, during the breeding season males survived less well than females (sex gap: 16%). Consistent with the 'risky male behaviour' hypothesis, the period for lowered male survival was restricted to the short mating season. Thus, sex differences in survival in a promiscuous mammal can be substantial even in the absence of sexual dimorphism. PMID:18426751

Kraus, Cornelia; Eberle, Manfred; Kappeler, Peter M

2008-07-22

186

The costs of risky male behaviour: sex differences in seasonal survival in a small sexually monomorphic primate  

PubMed Central

Male excess mortality is widespread among mammals and frequently interpreted as a cost of sexually selected traits that enhance male reproductive success. Sex differences in the propensity to engage in risky behaviours are often invoked to explain the sex gap in survival. Here, we aim to isolate and quantify the survival consequences of two potentially risky male behavioural strategies in a small sexually monomorphic primate, the grey mouse lemur Microcebus murinus: (i) most females hibernate during a large part of the austral winter, whereas most males remain active and (ii) during the brief annual mating season males roam widely in search of receptive females. Using a 10-year capture–mark–recapture dataset from a population of M. murinus in Kirindy Forest, western Madagascar, we statistically modelled sex-specific seasonal survival probabilities. Surprisingly, we did not find any evidence for direct survival benefits of hibernation—winter survival did not differ between males and females. By contrast, during the breeding season males survived less well than females (sex gap: 16%). Consistent with the ‘risky male behaviour’ hypothesis, the period for lowered male survival was restricted to the short mating season. Thus, sex differences in survival in a promiscuous mammal can be substantial even in the absence of sexual dimorphism. PMID:18426751

Kraus, Cornelia; Eberle, Manfred; Kappeler, Peter M

2008-01-01

187

Insights into the Preservation of the Homomorphic Sex-Determining Chromosome of Aedes aegypti from the Discovery of a Male-Biased Gene Tightly Linked to the M-Locus  

PubMed Central

The preservation of a homomorphic sex-determining chromosome in some organisms without transformation into a heteromorphic sex chromosome is a long-standing enigma in evolutionary biology. A dominant sex-determining locus (or M-locus) in an undifferentiated homomorphic chromosome confers the male phenotype in the yellow fever mosquito Aedes aegypti. Genetic evidence suggests that the M-locus is in a nonrecombining region. However, the molecular nature of the M-locus has not been characterized. Using a recently developed approach based on Illumina sequencing of male and female genomic DNA, we identified a novel gene, myo-sex, that is present almost exclusively in the male genome but can sporadically be found in the female genome due to recombination. For simplicity, we define sequences that are primarily found in the male genome as male-biased. Fluorescence in situ hybridization (FISH) on A. aegypti chromosomes demonstrated that the myo-sex probe localized to region 1q21, the established location of the M-locus. Myo-sex is a duplicated myosin heavy chain gene that is highly expressed in the pupa and adult male. Myo-sex shares 83% nucleotide identity and 97% amino acid identity with its closest autosomal paralog, consistent with ancient duplication followed by strong purifying selection. Compared with males, myo-sex is expressed at very low levels in the females that acquired it, indicating that myo-sex may be sexually antagonistic. This study establishes a framework to discover male-biased sequences within a homomorphic sex-determining chromosome and offers new insights into the evolutionary forces that have impeded the expansion of the nonrecombining M-locus in A. aegypti. PMID:24398378

Hall, Andrew Brantley; Timoshevskiy, Vladimir A.; Sharakhova, Maria V.; Jiang, Xiaofang; Basu, Sanjay; Anderson, Michelle A.E.; Hu, Wanqi; Sharakhov, Igor V.; Adelman, Zach N.; Tu, Zhijian

2014-01-01

188

Insights into the preservation of the homomorphic sex-determining chromosome of Aedes aegypti from the discovery of a male-biased gene tightly linked to the M-locus.  

PubMed

The preservation of a homomorphic sex-determining chromosome in some organisms without transformation into a heteromorphic sex chromosome is a long-standing enigma in evolutionary biology. A dominant sex-determining locus (or M-locus) in an undifferentiated homomorphic chromosome confers the male phenotype in the yellow fever mosquito Aedes aegypti. Genetic evidence suggests that the M-locus is in a nonrecombining region. However, the molecular nature of the M-locus has not been characterized. Using a recently developed approach based on Illumina sequencing of male and female genomic DNA, we identified a novel gene, myo-sex, that is present almost exclusively in the male genome but can sporadically be found in the female genome due to recombination. For simplicity, we define sequences that are primarily found in the male genome as male-biased. Fluorescence in situ hybridization (FISH) on A. aegypti chromosomes demonstrated that the myo-sex probe localized to region 1q21, the established location of the M-locus. Myo-sex is a duplicated myosin heavy chain gene that is highly expressed in the pupa and adult male. Myo-sex shares 83% nucleotide identity and 97% amino acid identity with its closest autosomal paralog, consistent with ancient duplication followed by strong purifying selection. Compared with males, myo-sex is expressed at very low levels in the females that acquired it, indicating that myo-sex may be sexually antagonistic. This study establishes a framework to discover male-biased sequences within a homomorphic sex-determining chromosome and offers new insights into the evolutionary forces that have impeded the expansion of the nonrecombining M-locus in A. aegypti. PMID:24398378

Hall, Andrew Brantley; Timoshevskiy, Vladimir A; Sharakhova, Maria V; Jiang, Xiaofang; Basu, Sanjay; Anderson, Michelle A E; Hu, Wanqi; Sharakhov, Igor V; Adelman, Zach N; Tu, Zhijian

2014-01-01

189

Increased secondary sex ratios in golden hamster litters sired by males without coagulating glands and seminal vesicles.  

PubMed

In golden hamsters, although bilateral ablation of paternal coagulating glands (CGX) and seminal vesicles (SVX) did not affect fertility, a higher number of male pups were born. The present study aimed at determining whether this male-biased sex ratio was due to an imbalance of fertilization by X and Y chromosome-bearing sperms or whether it was the consequence of a sex-related differential survival of embryos. The sex of embryos sired by sham-operated (SH) controls or males subjected to bilateral ablation of ampullary glands (AGX), CGX and SVX was determined from chromosomal spreads at 10 h post coitum and 10 days post coitum. The primary sex ratio of of the SH group did not deviate from the hypothetical sex ratio of 1:1. The sex ratios of zygotes from the three experimental groups did not differ from that of the controls. However, by mid gestation, the sex ratio was significantly higher in the SVX group (P < 0.05) and the CGX group (P < 0.005). The absence of secretions from the ampullary gland, coagulating gland and seminal vesicle had no effect on the primary sex ratio, thus these glands did not appear to affect fertilization by the X and Y chromosome-bearing sperm. The increased secondary sex ratios observed in the SVX and CGX groups were due to the preferential survival of males. PMID:8726869

Chow, P H; Cheung, M P; O, W S

1996-01-01

190

Sex chromosome pre-reduction in male meiosis of Lethocerus patruelis (Stål, 1854) (Heteroptera, Belostomatidae) with some notes on the distribution of the species  

PubMed Central

Abstract The karyotype and meiosis in males of giant water bug Lethocerus patruelis (Heteroptera: Belostomatidae: Lethocerinae) were studied using standard and fluorochrome (CMA3 and DAPI) staining of chromosomes. The species was shown to have 2n = 22A + 2m + XY where 2m are a pair of microchromosomes. NORs are located in X and Y chromosomes. Within Belostomatidae, Lethocerus patruelis is unique in showing sex chromosome pre-reduction in male meiosis, with the sex chromosomes undergoing reductional division at anaphase I and equational division at anaphase II. Cytogenetic data on the family Belostomatidae are summarized and compared. In addition, the structure of the male internal reproductive organs of Lethocerus patruelis is presented, the contemporary distribution of Lethocerus patruelis in Bulgaria and in the northern Aegean Islands is discussed, and the first information about the breeding and nymphal development of this species in Bulgaria is provided. PMID:24039515

Grozeva, Snejana; Kuznetsova, Valentina G.; Simov, Nikolay; Langourov, Mario; Dalakchieva, Svetla

2013-01-01

191

Male-biased sex ratios of fish embryos near a pulp mill: temporary recovery after a short-term shutdown.  

PubMed Central

In a previous study we showed that broods from the viviparous eelpout Zoarces viviparus were significantly male biased in 1998 in the vicinity of a large kraft pulp mill on the Swedish Baltic coast. One suggested hypothesis was that masculinizing compounds in the effluent were affecting gonadal differentiation of the embryos, resulting in skewed sex ratios. In this article, we present further evidence for a causal relationship between the exposure to the effluent and the male-biased sex ratios. Analyses of historical samples showed that the eelpout produced male-biased broods close to the mill in 1997 in addition to 1998. During 1999, the mill was shut down for 17 days, coinciding with the period when the gonads of the eelpout embryos differentiate. Subsequently, in the fall of 1999, the sex ratios were no longer male biased; however, the following year (2000), a significant male bias reappeared. Investigations at 13 sites for up to 4 years showed a relatively stable sex ratio around 50/50, with the exceptions by the mill and with few observations of deviating ratios at other sites. Several reports document endocrine disturbances in fish near pulp and paper mills, including the expression of male secondary sex characters in female fish. The repeatedly identified male bias at the investigated mill, the normalization after mill shutdown, and the reappearance the following year indicate that pulp mill effluents also can affect sex ratios of nearby fish. PMID:12153752

Larsson, D G Joakim; Förlin, Lars

2002-01-01

192

Same-sex sexual behaviors among male migrants in a context of male "marriage squeeze": results from an exploratory survey in urban Xi'an, China.  

PubMed

The male marriage squeeze in China may increase the prevalence of male same-sex sexual behaviors among unmarried male migrants who lack stable female sexual partners. The same-sex sexual behaviors among unmarried male migrants appear to be at high risk of transmission of human immunodeficiency virus (HIV) and sexually transmitted infections (STIs), mainly because of a lack of knowledge of these diseases. Using data from the "Survey on Reproductive Health and Family Life of Migrant Male Bachelors in Urban Areas" conducted in Xi'an City, Shaanxi Province, in December 2009 and January 2010, this study compares same-sex sexual behaviors of unmarried with that of married male migrants (including married but separated men who are migrating without their spouse or partner and cohabitating men who are migrating with their spouse or partner). It is reported that the prevalence of same-sex sexual behaviors among unmarried males reaches 11%, more than twice the 5.1% reported by married but separated men and thrice the 3.8% reported by cohabitating men. It also appears that the same-sex sexual behaviors is significantly associated with men's attitudes toward same-sex sexual behaviors (odds ratio = 1.59, p < .001), toward life-long bachelorhood (odds ratio = 1.35, p < .01), and with marital status (odds ratio = 0.37, p < .01). The frequency of condom use appears to be higher among unmarried men than among men who are married, whether or not they migrated with their wives, and is significantly associated with scores on knowledge about HIV/AIDS (estimated coefficient = .12, p < .001) and STIs (estimated coefficient = .22, p < .01). It is also associated with the likelihood of same-sex sexual behaviors (estimated coefficients = .83, p < .01) and marital status (estimated coefficients for married but separated = -.50, p < .05; estimated coefficients for cohabitating = -.77, p < .001). PMID:22782362

Yang, Xueyan; Attané, Isabelle; Li, Shuzhuo; Yang, Bo

2012-11-01

193

Sex-specific visual performance: female lizards outperform males in motion detection  

PubMed Central

In animal communication, complex displays usually have multiple functions and, male and female receivers often differ in their utilization and response to different aspects of these displays. The perceptual variability hypothesis suggests that different aspects of complex signals differ in their ability to be detected and processed by different receivers. Here, we tested whether receiver male and female Sceloporus graciosus lizards differ in visual motion detection by measuring the latency to the visual grasp response to a motion stimulus. We demonstrate that in lizards that largely exhibit complex motions as courtship signals, female lizards are faster than males at visually detecting motion. These results highlight that differential signal utilization by the sexes may be driven by variability in the capacity to detect different display properties. PMID:19656865

Nava, Saúl S.; Conway, Mirela; Martins, Emília P.

2009-01-01

194

Sex-specific visual performance: female lizards outperform males in motion detection.  

PubMed

In animal communication, complex displays usually have multiple functions and, male and female receivers often differ in their utilization and response to different aspects of these displays. The perceptual variability hypothesis suggests that different aspects of complex signals differ in their ability to be detected and processed by different receivers. Here, we tested whether receiver male and female Sceloporus graciosus lizards differ in visual motion detection by measuring the latency to the visual grasp response to a motion stimulus. We demonstrate that in lizards that largely exhibit complex motions as courtship signals, female lizards are faster than males at visually detecting motion. These results highlight that differential signal utilization by the sexes may be driven by variability in the capacity to detect different display properties. PMID:19656865

Nava, Saúl S; Conway, Mirela; Martins, Emília P

2009-12-23

195

The role of male-male relationships in partner violence treatment groups: the effects of improving same sex relationships on attachment  

E-print Network

from their peers creates fear of negative evaluation and rejection to avoid humiliating labels such as ?sissy?, thus leading to conformity to traditional normative behaviors (Jennings & Murphy, 2000, p. 23). Traditional masculine socialization... guards against male and female induced shame and humiliation, yet also creates a barrier to emotional expressiveness, connection, and sensitivity with both sexes (Jennings & Murphy, 2000). 7 Male-Male Disconnection There are many other...

Barnes, Ashley D.

2009-05-15

196

Carotenoid-Based Ornaments of Female and Male American Goldfinches (Spinus tristis) Show Sex-Specific Correlations  

E-print Network

348 Carotenoid-Based Ornaments of Female and Male American Goldfinches (Spinus tristis) Show Sex of carotenoid-based bill and plumage ornamentation in Amer- ican goldfinches Spinus tristis, a species in which

Murphy, Troy G.

197

Tardy females, impatient males: protandry and divergent selection on arrival date in the two sexes of the barn swallow  

Microsoft Academic Search

Protandry reflects the earlier arrival of males than females to the site of reproduction. Such protandry is hypothesised to\\u000a arise from sex differences in costs and benefits of early arrival. I investigated temporal patterns of arrival date of male\\u000a and female barn swallows Hirundo rustica and temporal patterns of selection to test the hypothesis that sex differences in selection account

Anders Pape Møller

2007-01-01

198

Self Ratings of Dependency\\/Addiction Regarding Drugs, Sex, Love, and Food: Male and Female College Students  

Microsoft Academic Search

To what degree do addictions to drugs, sex, love, and food correlate with each other? Are there meaningful sex differences in the addictions? To study this, 9,313 college students (3,083 males, 6,230 females) rated 13 items on 0–100 scales for their dependency\\/addiction to the things represented by the items. Results indicated that males reported significantly more addictions than females, but

RUSSELL EISENMAN; M. L. DANTZKER; LEE ELLIS

2004-01-01

199

Epidemiology of male same-sex behaviour and associated sexual health indicators in low- and middle-income countries: 2003-2007 estimates  

Microsoft Academic Search

Objectives: To conduct a systematic review of published and unpublished data from research and public health information systems on the prevalence of male-to-male sex in the total male population; as well as among men who have sex with men (MSM), data on prevalence of heterosexual activity and heterosexual unions; prevalence of condom use with male and female partners; and prevalence

K Konda; E R Segura; R Lyerla; Carlos F Caceres

2010-01-01

200

H2AX Is Required for Chromatin Remodeling and Inactivation of Sex Chromosomes in Male Mouse Meiosis  

Microsoft Academic Search

During meiotic prophase in male mammals, the X and Y chromosomes condense to form a macrochromatin body, termed the sex, or XY, body, within which X- and Y-linked genes are transcriptionally repressed. The molecular basis and biological function of both sex body formation and meiotic sex chromosome inactivation (MSCI) are unknown. A phosphorylated form of H2AX, a histone H2A variant

Oscar Fernandez-Capetillo; Shantha K. Mahadevaiah; Arkady Celeste; Peter J. Romanienko; R. Daniel Camerini-Otero; William M. Bonner; Katia Manova; Paul Burgoyne; André Nussenzweig

2003-01-01

201

Sex differences in the genetic architecture of lifespan in a seed beetle: extreme inbreeding extends male lifespan  

PubMed Central

Background Sex differences in lifespan are ubiquitous throughout the animal kingdom but the causes underlying this phenomenon remain poorly understood. Several explanations based on asymmetrical inheritance patterns (sex chromosomes or mitochondrial DNA) have been proposed, but these ideas have rarely been tested experimentally. Alternatively, sexual dimorphism in lifespan could result from sex-specific selection, caused by fundamental differences in how males and females optimize their fitness by allocating resources into current and future reproduction. Results Here we used sex-specific responses to inbreeding to study the genetic architecture of lifespan and mortality rates in Callosobruchus maculatus, a seed beetle that shows sexual dimorphism in lifespan. Two independent assays revealed opposing sex-specific responses to inbreeding. The combined data set showed that inbred males live longer than outbred males, while females show the opposite pattern. Both sexes suffered reduced fitness measured as lifetime reproductive success as a result of inbreeding. Conclusion No model based on asymmetrical inheritance can explain increased male lifespan in response to inbreeding. Our results are however compatible with models based on sex-specific selection on reproductive strategies. We therefore suggest that sex-specific differences in lifespan in this species primarily result from sexually divergent selection. PMID:19200350

Bilde, Trine; Maklakov, Alexei A; Meisner, Katrine; la Guardia, Lucia; Friberg, Urban

2009-01-01

202

Sex ratios of triploids and gynogenetic diploids induced in the hybrid sturgeon, the bester ( Huso huso female× Acipenser ruthenus male)  

Microsoft Academic Search

The sex ratios of triploids and gynogenetic diploids in the hybrid sturgeon, the bester (Huso huso female×Acipenser ruthenus male), have been investigated to confirm the possibilities of sex control by chromosome manipulation in sturgeon. Viable gynogenetic diploids were produced by activating eggs with ultraviolet-irradiated bester sperm followed by heatshock treatment. Triploids were induced by the same method after fertilization of

Naotaka Omoto; Mamoru Maebayashi; Shinji Adachi; Katsutoshi Arai; Kohei Yamauchi

2005-01-01

203

Where have all the females gone? Male biased sex-ratio in Arctodiaptomus alpinus (Imhof, 1885) in alpine lakes  

NASA Astrophysics Data System (ADS)

In populations with both males and females sex-ratio is one of the driving forces of population dynamics. It influences fecundity, inbreeding and social interactions. Sex-ratio is affected by several biotic and abiotic factors, either by selective killing of one sex or by inducing migrations. In alpine lakes of Triglav National Park, Slovenia, an extremely male biased sex-ratio in Arctodiaptomus alpinus (Imhof, 1885) was regularly observed since 1992. We analysed population dynamics and sex-ratio of A. alpinus in three alpine lakes (Jezero v Ledvicah, Rjavo jezero and Zgornje Kriško jezero) from Triglav National Park in Slovenia. In addition to seasonal dynamics we also researched long-term changes in sex-ratio (in a period of 11 years from autumn samples) as a result of increased air-temperature, and zooplankton diurnal vertical migrations. Adults of both sexes were found to appear at the same time in the water collumn with males prevailing throughout the season. A similar trend was found in copepodites CV. The percent of adult females began increasing in late summer, when there were no more copepodites and recrutation from copepodites CV to adults stopped, while male mortality increased. All cohorts of A. alpinus were found to perform diurnal vertical migrations. Both adult and CV females remained close to the bottom during the day and migrated vertically during the night. Results of the long-term study show no changes in sex-ratio in autumn.

Žibrat, U.; Brancelj, A.

2009-04-01

204

Fine structure and meiotic behaviour of the male multiple sex chromosomes in the genus Alouatta.  

PubMed

The meiotic cytology and fine structure of the sex multiples in males from two species of the genus Alouatta are presented and compared with descriptions from other species of this genus. As shown in pachytene by synaptonemal complex analysis and in metaphase I by spreading, there is a quadrivalent in male meiosis in A. caraya, which is formed by an X(1)X(2)Y(1)Y(2) complex, while in A. palliata there is a trivalent formed by an X(1)X(2)Y(1) complex. Chromosome painting with human probes shows that A. caraya sex multiples share the same components as those of A. seniculus sara and A. seniculus arctoidea. However, as shown here for A. palliata and by others in A. fusca, there are differences among the multiples of some species. It is shown that in this genus there are several varieties of sex multiples that share some features, and that the origin of these multiples is most probably a primitive development in the genus Alouatta. PMID:15545739

Solari, A J; Rahn, M I

2005-01-01

205

Sex differences in recovery from PTSD in male and female interpersonal assault survivors.  

PubMed

Men and women differ in exposure to trauma and the development of posttraumatic stress disorder (PTSD); however, research regarding sex differences in recovery from PTSD has been sparse. This study evaluated the treatment response trajectory for 69 male and female interpersonal assault survivors, using a modified Cognitive Processing Therapy (CPT) protocol that allowed survivors to receive up to18 sessions of CPT, with treatment end determined by therapy progress. Few sex differences were observed in trauma history, baseline PTSD and depressive severity, Axis I comorbidity, anger, guilt and dissociation. Women did report more sexual assault in adulthood and elevated baseline guilt cognitions, whereas men reported more baseline anger directed inward. Attrition and total number of sessions did not differ by sex. Over the course of treatment and follow-up, men and women demonstrated similar rates of change in PTSD and depressive symptoms. However, medium effect sizes on both of these primary outcomes at the 3-month follow-up assessment favored women. Several differences in the slope of change emerged on secondary outcomes such that women evidenced more rapid gains on global guilt, guilt cognitions, anger/irritability, and dissociation. Results suggest that male survivors may warrant additional attention to address these important clinical correlates. PMID:23510841

Galovski, Tara E; Blain, Leah M; Chappuis, Courtney; Fletcher, Thomas

2013-06-01

206

Sex hormone influence on hepatitis in young male A/JCr mice infected with Helicobacter hepaticus.  

PubMed

Hepatitis B virus (HBV), the leading cause of human hepatocellular carcinoma, is especially virulent in males infected at an early age. Likewise, the murine liver carcinogen Helicobacter hepaticus is most pathogenic in male mice infected before puberty. We used this model to investigate the influence of male sex hormone signaling on infectious hepatitis. Male A/JCr mice were infected with H. hepaticus or vehicle at 4 weeks and randomized into surgical and pharmacologic treatment groups. Interruption of androgen pathways was confirmed by hormone measurements, histopathology, and liver gene and Cyp4a protein expression. Castrated males and those receiving the competitive androgen receptor antagonist flutamide had significantly less severe hepatitis as determined by histologic activity index than intact controls at 4 months. Importantly, the powerful androgen receptor agonist dihydrotestosterone did not promote hepatitis. No effect on hepatitis was evident in males treated with the 5alpha-reductase inhibitor dutasteride, the peroxisome proliferator-activated receptor-alpha agonist bezafibrate, or the nonsteroidal anti-inflammatory drug flufenamic acid. Consistent with previous observations of hepatitis-associated liver-gender disruption, transcriptional alterations involved both feminine (cytochrome P450 4a14) and masculine (cytochrome P450 4a12 and trefoil factor 3) genes, as well gender-neutral (H19 fetal liver mRNA, lipocalin 2, and ubiquitin D) genes. Hepatitis was associated with increased unsaturated C(18) long-chain fatty acids (oleic acid and linoleic acid) relative to saturated stearic acid. Our results indicate that certain forms of androgen interruption can inhibit H. hepaticus-induced hepatitis in young male mice, whereas androgen receptor agonism does not worsen disease. This raises the possibility of targeted hormonal therapy in young male patients with childhood-acquired HBV. PMID:18559427

Theve, Elizabeth J; Feng, Yan; Taghizadeh, Koli; Cormier, Kathleen S; Bell, David R; Fox, James G; Rogers, Arlin B

2008-09-01

207

Sex-Specific Signaling in the Blood–Brain Barrier Is Required for Male Courtship in Drosophila  

PubMed Central

Soluble circulating proteins play an important role in the regulation of mating behavior in Drosophila melanogaster. However, how these factors signal through the blood–brain barrier (bbb) to interact with the sex-specific brain circuits that control courtship is unknown. Here we show that male identity of the blood–brain barrier is necessary and that male-specific factors in the bbb are physiologically required for normal male courtship behavior. Feminization of the bbb of adult males significantly reduces male courtship. We show that the bbb–specific G-protein coupled receptor moody and bbb–specific Go signaling in adult males are necessary for normal courtship. These data identify sex-specific factors and signaling processes in the bbb as important regulators of male mating behavior. PMID:23359644

Hoxha, Valbona; Lama, Chamala; Chang, Peter L.; Saurabh, Sumit; Patel, Naiya; Olate, Nicole; Dauwalder, Brigitte

2013-01-01

208

Diversity of commercial sex among men and male-born trans people in three Peruvian cities  

PubMed Central

In Peru, commercial sex involving men and male-born travestis, transgenders and transsexuals (CSMT) is usually represented as a dangerous practice carried out on the streets by people experiencing economic hardship and social exclusion. However, in reality little is known about the complexities of this practice in Peru. This paper presents findings from an ethnographic study of the characteristics, patterns and socio-cultural aspects of CSMT in three Peruvian cities. The study included participant observation in sex work venues and interviews with 42 sex workers and 25 key informants. We found that CSMT in Peru takes many forms (some not previously described in the country) and is practised in different places by people from various socioeconomic levels. In many cases, the practice appears linked to ideals of social mobility, migratory experiences and other economic activities. In addition, the increasing use of the internet and mobile phones has changed patterns of sex work in Peru. We review the implications of these findings for future research and public health interventions. PMID:21936651

Zúñiga, Mario; Zunt, Joseph; Mejía, Carolina; Montano, Silvia; Sánchez, Jorge L.

2011-01-01

209

Randomised controlled trial of alternative male and female condom promotion strategies targeting sex workers in Madagascar  

PubMed Central

Objectives To assess whether individual clinic?based counselling as a supplement to peer education for male and female condom promotion leads to greater use of protection and lower STI prevalence among sex workers in Madagascar already exposed to intensive male condom promotion. Methods In two public dispensaries in Madagascar, a total of 901 sex workers were randomly allocated between two alternative male and female condom promotion interventions: peer education only, or peer education supplemented with individual clinic?based counselling. Participants were followed for 12?months. Every 2?months they made clinic visits, where they were interviewed on condom use. Peer educators counselled all participants on condom use as they accompanied their assigned participants to study visits. Participants assigned to receive the supplemental intervention were counselled by a trained clinician following study interviews. Participants were tested and treated for chlamydia, gonorrhoea and trichomoniasis every 6?months. We used logistic regression to assess whether the more intensive intervention was associated with reduced STI prevalence. Use of protection with clients and non?paying partners was assessed by study arm, site, and visit. Results There was no statistically significant association between study arm and aggregated STI prevalence. No substantial differences in levels of reported protection were noted between study groups. Conclusions This study found little evidence for gains from more thorough clinical counselling on male and female condom use. These findings suggest that less clinically intensive interventions such as peer education could be suitable for male and female condom promotion in populations already exposed to barrier method promotion. PMID:17591662

Hoke, Theresa H; Feldblum, Paul J; Van Damme, Kathleen; Nasution, Marlina D; Grey, Thomas W; Wong, Emelita L; Ralimamonjy, Louisette; Raharimalala, Leonardine; Rasamindrakotroka, Andry

2007-01-01

210

A new male sex-pheromone and novel cuticular cues for chemical communication in Drosophila  

PubMed Central

Summary Background In many insect species, cuticular hydrocarbons serve as pheromones that can mediate complex social behaviors. In Drosophila melanogaster, several hydrocarbons including the male sex pheromone 11-cis-vaccenyl acetate (cVA) and female-specific 7,11-dienes influence courtship behavior and can function as cues for short-term memory associated with the mating experience. Behavioral and physiological studies suggest that other unidentified chemical communication cues are likely to exist. To more fully characterize the hydrocarbon profile of the D. melanogaster cuticle, we applied direct ultraviolet laser desorption/ionization orthogonal time-of-flight mass spectrometry (UV-LDI-o-TOF MS) and analyzed the surface of intact fruit flies at a spatial resolution of approximately 200 ?m. Results We report the chemical and spatial characterization of 28 species of cuticular hydrocarbons, including a new major class of oxygen-containing compounds. Using UV-LDI MS, pheromones previously shown to be expressed exclusively by one sex, e.g. cVA, 7,11-heptacosadiene, and 7,11-nonacosadiene, appear to be found on both male and female flies. In males, cVA co-localizes at the tip of the ejaculatory bulb with a second acetylated hydrocarbon named CH503. We describe the chemical structure of CH503 as 3-O-acetyl-1,3-dihydroxy-octacosa-11,19-diene and show one behavioral role for this compound as a long-lived inhibitor of male courtship. Like cVA, CH503 is transferred from males to females during mating. Unlike cVA, CH503 remains on the surface of females for at least 10 days. Conclusions Oxygenated hydrocarbons comprise one major previously undescribed class of compounds on the Drosophila cuticular surface. In addition to cVA, a newly-discovered long chain acetate, CH503, serves as a mediator of courtship-related chemical communication. PMID:19615904

Dreisewerd, Klaus; Luftmann, Heinrich; Müthing, Johannes; Pohlentz, Gottfried; Kravitz, Edward A.

2009-01-01

211

Induction of Female-to-Male Sex Change in Adult Zebrafish by Aromatase Inhibitor Treatment  

NASA Astrophysics Data System (ADS)

This study investigated whether undifferentiated germ and/or somatic stem cells remain in the differentiated ovary of a species that does not undergo sex changes under natural conditions and retain their sexual plasticity. The effect of aromatase inhibitor (AI)-treatment on sexually mature female zebrafish was examined. A 5-month AI treatment caused retraction of the ovaries after which testes-like organs appeared, and cyst structures filled with spermatozoa-like cells were observed in sections of these tissues. Electron microscopic observations revealed that these cells appeared as large sperm heads without tails. Sperm formation was re-examined after changing the diet to an AI-free food. A large number of normal sperm were obtained after eight weeks, and no formation of ovarian tissue was observed. Artificial fertilization using sperm from the sex-changed females was successful. These results demonstrated that sex plasticity remains in the mature ovaries of this species.

Takatsu, Kanae; Miyaoku, Kaori; Roy, Shimi Rani; Murono, Yuki; Sago, Tomohiro; Itagaki, Hideyuki; Nakamura, Masaru; Tokumoto, Toshinobu

2013-12-01

212

Modeling the suppression of sea lamprey populations by use of the male sex pheromone  

USGS Publications Warehouse

The suppression of sea lamprey populations, Petromyzon marinus (Linnaeus), was modeled using four different applications of the male sex pheromone: (1) pheromone-baited traps that remove females from the spawning population, (2) pheromone-baited decoys that exhaust females before they are able to spawn, (3) pheromone-enhanced sterile males that increase the proportion of non-fertile matings, and (4) camouflaging of the pheromone emitted by calling males to make it difficult for females to find a mate. The models indicated that thousands of traps or hundreds of thousands of decoys would be required to suppress a population of 100,000 animals. The potential efficacy of pheromone camouflages is largely unknown, and additional research is required to estimate how much pheromone is needed to camouflage the pheromone plumes of calling males. Pheromone-enhanced sterile males appear to be a promising application in the Great Lakes. Using this technique for three generations each of ca. 7 years duration could reduce sea lamprey populations by 90% for Lakes Huron and Ontario and by 98% for Lake Michigan, based on current trapping operations that capture 20 to 30% of the population each year.

Klassen, Waldemar; Adams, Jean V.; Twohey, Michael B.

2005-01-01

213

STI prevention and the male sex industry in London: evaluating a pilot peer education programme  

PubMed Central

Objective: To evaluate the effectiveness of a pilot peer education STI prevention programme with male sex workers. Design: A process and outcome evaluation of the pilot programme undertaken in three London male escort agencies, using a quasi-experimental design. Subjects: Workers in three London escort agencies, including 88 who completed a questionnaire, five peer educators, and a further 16 men (including management) working in two of these agencies. Methods: A peer education STI prevention programme run by the Working Men Project (WMP), a specialist sexual health service for male sex workers, was piloted in two London escort agencies. Five male sex workers participated in a 2 day peer education training programme. They then returned to their respective agencies to disseminate information and condoms, in an attempt to influence norms of behaviour. An outcome evaluation aimed to assess changes in STI related knowledge, high risk sexual behaviour, and attendance at a sexual health service. A pre-intervention questionnaire assessing variables such as STI related knowledge, sexual behaviour, and demographic information was administered in both agency A and agency B and a third agency, C, which acted as a control. Ten weeks after the peer educators returned to their agencies, the same questionnaire was administered in the same agencies. Peer educator referrals to the WMP were also recorded over this time period. The process evaluation involved interviews and focus groups with peer educators, and the completion of diaries about their experiences in the role. A further 16 men working in the agencies (including managers and an owner) were interviewed about their experience of the programme. Participant observation was also undertaken through regular outreach work to the agencies. Results: 57 men completed the questionnaire at time 1 and 44 at time 2. Unfortunately, only 13 of these were matched, precluding any meaningful analysis of change in STI related knowledge and sexual behaviour. The questionnaire provided a profile of the men working in the agencies. Of the 88 men who completed the questionnaire at least once, the majority were homosexual, and in their late teens/early 20s. Most were of a "white" ethnic group, though there was some range within these categories. Most preferred to speak English and education levels were high. Relative STI knowledge revealed a high understanding of HIV and hepatitis B, moderate understanding of gonorrhoea, syphilis, genital warts and herpes, and little knowledge of non-specific urethritis (NSU) or chlamydia. Sexual behaviour suggested a highly sexually active population with both male and female paying and non-paying partners. Condom use was highest for paying partners, particularly for anal sex. Condom use for oral sex with all partners was less consistent, and condom use for all types of sex with regular partners was lower than with other partners. The small number of men engaging in vaginal sex with paying and regular partners were less likely to use condoms. 26 new patients registered at the WMP as a result of peer educator referrals, representing 65% of all new contacts over the study period. The process evaluation revealed that while the training programme was considered adequate and while peer educators felt the programme and their roles to be a success, their experience of the role was difficult. The role of management support was crucial in supporting the programme. The assumption that "peers" are particularly effective educators was not borne out by the results. While peers were considered suitable to discuss some aspects of the industry, many preferred to consult "professionals" about health related matters. The concept of "peers" was problematic with most of the men drawing "peers" from subgroups within the agencies. Other constraints on behaviour such as a lack of power, particularly with regard to a lack of management support, or poverty, had a substantial impact on behaviour which were not influenced by the peer educators. Conclusions: The study illustrated the difficulties

Ziersch, A; Gaffney, J; Tomlinson, D

2000-01-01

214

Self-Organization in the Battle of the Sexes  

NASA Astrophysics Data System (ADS)

This paper presents a spatial version of the iterated battle of the sexes game in which every one individual plays with his nearest partners and imitates the optimal strategy of his nearest mate neighbors. It is concluded that the spatial structure enables the emergence of clusters of coincident choices, leading to the mean payoff per encounter to values that are accessible only in the cooperative two-person game scenario, which constitutes a notable case of self-organization.

Alonso-Sanz, Ramón

215

Relationship Characteristics and HIV Transmission Risk in Same-sex Male Couples in HIV Serodiscordant Relationships  

PubMed Central

Unprotected anal intercourse (UAI) remains a main risk factor for HIV among men who have sex with men (MSM) and this is of particular concern for partners of HIV serodiscordant status. However, HIV transmission risk has been demonstrated to vary by the sexual position adopted among partners. Guided by interdependence theory, this study examined how relational factors were differentially associated with risk taking (HIV-positive/insertive and HIV-negative/receptive) and strategic positioning (HIV-positive/receptive and HIV-negative/insertive) UAI withinserodiscordant same-sex male couples. HIV-positive men and their HIV-negative partners (ncouples=91; nindividuals=182) simultaneously but independently completed computerized questionnaires and HIV-positive men had blood drawn for viral load.A minority of couples (30%) engaged in risk taking and/or strategicpositioning unprotected anal sex. Results of multinomial logistic regressionindicated that HIV-negative partners’ levels of relationship commitment were positively associated with the odds of engaging in both risk taking and strategic positioning sexual behaviors. For HIV-negative partners, reports of relationship intimacy, autonomy, and sexual satisfaction were negatively associated with odds of reporting risk taking behavior. In contrast, HIV-positive partners’reported sexual satisfaction was positively associated with odds of engaging in risk taking behavior. Findings suggested that aspects of relational quality may be differentially associated with sexual decision making for same-sex male couples in serodiscordant relationships. Study findings lend support for the incorporation ofdiscussions of HIV risk reduction strategies, enhancing communication between partners, and support for general relationship functioning in HIV care. PMID:24243004

Starks, Tyrel J.; Gamarel, Kristi E.; Johnson, Mallory O.

2014-01-01

216

Polymorphisms in the maternal sex steroid pathway are associated with behavior problems in male offspring  

PubMed Central

Objective Slight perturbations in maternal sex steroid production and metabolism may interfere with normal fetal neurodevelopment. The balance of maternal estrogens and androgens may have direct fetal effects, may influence the fetal hypothalamic-pituitary-gonadal axis or may alter local hormonal activity within the fetal brain. We investigated maternal functional polymorphisms of CYP17, CYP19 and CYP1B1, which control three major enzymatic steps in sex steroid biosynthesis and metabolism, in relation to childhood behaviors. Methods The Mount Sinai Children’s Environmental Health Study enrolled a multiethnic urban pregnancy cohort from 1998–2002 (n = 404). DNA was obtained from maternal blood (n=149) and from neonatal cord blood (n=53). At each visit, mothers completed the Behavior Assessment System for Children (BASC), a parent-reported questionnaire used to evaluate children for behavior problems. We focused on problem behaviors more commonly associated with ADHD (hyperactivity, attention problems, externalizing behaviors, conduct disorder, poor adaptability) to see if maternal genetic variants in sex steroid production and metabolism influence sexually-dimorphic behaviors in offspring. Results The more active gene variants were significantly associated with Attention Problems and poorer Adaptive Skills in male compared to female offspring. The CYP19 variant allele was also significantly associated with worse scores for boys on the Hyperactivity, Externalizing Problems Composite and Adaptive Skills Composite scales (p < 0.05). Conclusion We observed maladaptive behaviors in the male offspring of mothers who carried functional polymorphisms in the sex steroid pathway. The strongest associations were in domains commonly affected in Attention Deficit-Hyperactivity Disorder. PMID:22336992

Miodovnik, Amir; Diplas, Andreas I.; Chen, Jia; Zhu, Chenbo; Engel, Stephanie M.; Wolff, Mary S.

2012-01-01

217

The impact of sex hormone concentrations on decision-making in females and males  

PubMed Central

Human decision-making has been frequently studied and sex differences have been reported. Interestingly, previous results of hormone concentration on decision-making are somewhat inconsistent, regarding the impact of menstrual cycle phase in women or the influence of testosterone concentration on decision-making in women and men. However, the influence of the female sex hormone concentration (estradiol, progesterone) and the impact of oral contraceptive intake have rarely been examined and data regarding the effect of daytime variations of male testosterone are lacking. Moreover if personality factors such as sensation seeking, impulsivity, and anxiety influence decision-making, sex-specific effects, act as modulators is unclear. In the present study 71 women and 45 men were enrolled. All participants performed an evaluated decision-making task measuring risk-taking behavior on the basis of contingencies (Haegler et al., 2010), which can be carried out several times without a learning effect. Saliva samples were collected to obtain estradiol, progesterone, and testosterone levels. Additionally, all participants completed questionnaires measuring various personality factors. Data analysis revealed no sex differences in decision-making and no significant impact of testosterone concentration on behavioral performance in women or men. However, a significant negative correlation between progesterone concentration of women in the luteal phase and their performance in the risk-averse condition was obtained. Interestingly, a significant correlation between trait anxiety and decision-making occurred in females and males. Despite similar risky decision-making of women and men and no influence of testosterone concentration, menstrual cycle phase showed an effect on risk taking in women. In contrary to other studies, our findings provide rather subtle evidence for hormonal influences in decision-making, which may be primarily explained by task factors. PMID:25414632

Derntl, Birgit; Pintzinger, Nina; Kryspin-Exner, Ilse; Schöpf, Veronika

2014-01-01

218

Plant odorants interfere with detection of sex pheromone signals by male Heliothis virescens  

PubMed Central

In many insects, mate finding relies on female-released sex pheromones, which have to be deciphered by the male olfactory system within an odorous background of plant volatiles present in the environment of a calling female. With respect to pheromone-mediated mate localization, plant odorants may be neutral, favorable, or disturbing. Here we examined the impact of plant odorants on detection and coding of the major sex pheromone component, (Z)-11-hexadecenal (Z11-16:Ald) in the noctuid moth Heliothis virescens. By in vivo imaging the activity in the male antennal lobe (AL), we monitored the interference at the level of olfactory sensory neurons (OSN) to illuminate mixture interactions. The results show that stimulating the male antenna with Z11-16:Ald and distinct plant-related odorants simultaneously suppressed pheromone-evoked activity in the region of the macroglomerular complex (MGC), where Z11-16:Ald-specific OSNs terminate. Based on our previous findings that antennal detection of Z11-16:Ald involves an interplay of the pheromone binding protein (PBP) HvirPBP2 and the pheromone receptor (PR) HR13, we asked if the plant odorants may interfere with any of the elements involved in pheromone detection. Using a competitive fluorescence binding assay, we found that the plant odorants neither bind to HvirPBP2 nor affect the binding of Z11-16:Ald to the protein. However, imaging experiments analyzing a cell line that expressed the receptor HR13 revealed that plant odorants significantly inhibited the Z11-16:Ald-evoked calcium responses. Together the results indicate that plant odorants can interfere with the signaling process of the major sex pheromone component at the receptor level. Consequently, it can be assumed that plant odorants in the environment may reduce the firing activity of pheromone-specific OSNs in H. virescens and thus affect mate localization. PMID:23060749

Pregitzer, Pablo; Schubert, Marco; Breer, Heinz; Hansson, Bill S.; Sachse, Silke; Krieger, Jürgen

2012-01-01

219

Social Deficits in Male Children and Adolescents with Sex Chromosome Aneuploidy: A Comparison of XXY, XYY, and XXYY Syndromes  

ERIC Educational Resources Information Center

We compare social skills in three groups of males with sex chromosome aneuploidies (SCAs) using the Social Responsiveness Scale (SRS). Participants included males with XXY (N = 102, M = 10.08 years), XYY (N = 40, M = 9.93 years), and XXYY (N = 32, M = 11.57 years). XXY had lower (better) SRS scores compared to XYY and XXYY. Scores were not…

Cordeiro, Lisa; Tartaglia, Nicole; Roeltgen, David; Ross, Judith

2012-01-01

220

MULTIPLE-MATING OF MALE AND FEMALE CODLING MOTH (LEPIDOPTERA: TORTRICIDAE) IN APPLE ORCHARDS TREATED WITH SEX PHEROMONE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Studies were conducted with codling moth, Cydia pomonella (L.), to evaluate the mating status of male and female moths in apple, Malus domestica (Borkhausen), orchards treated with and without sex pheromone dispensers. Laboratory studies first examined the effect of multiple mating of male and femal...

221

Homosexual threat, negative attitudes toward masturbation, sex guilt, and males' sexual and affective reactions to explicit sexual films  

Microsoft Academic Search

Subjective sexual arousal and affective responses of 215 undergraduate males to films of masturbatory, homosexual, and heterosexual behavior were studied as a function of personality differences in negative attitudes toward masturbation, homosexual threat, and sex guilt. The film of heterosexual behavior elicited more subjective sexual arousal and less disgust, anger, shame, depression, and guilt than did the films of male

Donald L. Mosher; Kevin E. OGrady

1979-01-01

222

Traumagenic Dynamics in Adult Women Survivors of Childhood Sexual Abuse vs. Adolescent Male Sex Offenders with Similar Histories.  

ERIC Educational Resources Information Center

Female childhood sexual abuse survivors and adolescent male sexual offenders with a history of childhood sexual abuse were assessed using the Trauma-Related Beliefs Questionnaire. Results suggested that male sex offenders hold high levels of traumagenic beliefs common in females, especially related to trust and betrayal. (Author)

Edwards, Carla; Hendrix, Rebecca

2001-01-01

223

Identification and Validation of a New Male Sex-Specific ISSR Marker in Pointed Gourd (Trichosanthes dioica Roxb.)  

PubMed Central

The aim of the present study was to develop a genetic sex marker for the pointed gourd (Trichosanthes dioica Roxb.) to allow gender determination at any stage in the life cycle. Screening of genomic DNA with intersimple sequence repeat (ISSR) primers was used to discover sex-specific touch-down polymerase chain reaction (Td-PCR) amplification products. Using pooled DNA from male and female genotypes and 42 ISSR primers, a putative male specific marker (~550?bp) was identified. DNA marker specific to male is an indication of existence of nonepigenetic factors involved in gender development in pointed gourd. The ISSR technique has proved to be a reliable technique in gender determination of pointed gourd genotypes at the seedling phenophase. The sex marker developed here could also be used as a starting material towards sequence characterization of sex linked genes for better understanding the developmental as well as evolutionary pathways in sexual dimorphism. PMID:25538949

Adhikari, Sinchan; Saha, Soumen; Bandyopadhyay, Tapas Kumar

2014-01-01

224

The Syndemic Condition of Psychosocial Problems and HIV Risk Among Male Sex Workers in Ho Chi Minh City, Vietnam  

PubMed Central

In Vietnam, the co-occurrence (i.e., “syndemic”) of psychosocial factors (e.g., depression and substance use) may disproportionately burden male sex workers and increase their HIV risk. A comprehensive survey was conducted among 300 male sex workers in Ho Chi Minh City, Vietnam in 2010. We performed logistic regression to examine the association between the syndemic variable – a count score of the number of 5 psychosocial conditions endorsed – and unprotected anal sex (UAS) in the past. One-third of participants reported any UAS, and 42% reported ? 2 psychosocial health problems. In multivariable models, experiencing ? 4 psychosocial health problems was significantly associated with UAS. Every unit increase in number of psychosocial health problems was associated with a 25%–30% increase in odds of UAS. Understanding the syndemic condition and its association with HIV risk among male sex workers in Vietnam may lead to the development of more effective, comprehensive interventions. PMID:24081899

Biello, Katie; Colby, Donn; Closson, Elizabeth; Mimiaga, Matthew J.

2015-01-01

225

The syndemic condition of psychosocial problems and HIV risk among male sex workers in Ho Chi Minh City, Vietnam.  

PubMed

In Vietnam, the co-occurrence (i.e., "syndemic") of psychosocial factors (e.g., depression and substance use) may disproportionately burden male sex workers and increase their HIV risk. A comprehensive survey was conducted among 300 male sex workers in Ho Chi Minh City, Vietnam in 2010. We performed logistic regression to examine the association between the syndemic variable-a count score of the number of five psychosocial conditions endorsed-and unprotected anal sex (UAS) in the past. One-third of participants reported any UAS, and 42 % reported ?2 psychosocial health problems. In multivariable models, experiencing ?4 psychosocial health problems was significantly associated with UAS. Every unit increase in number of psychosocial health problems was associated with a 25-30 % increase in odds of UAS. Understanding the syndemic condition and its association with HIV risk among male sex workers in Vietnam may lead to the development of more effective, comprehensive interventions. PMID:24081899

Biello, Katie B; Colby, Donn; Closson, Elizabeth; Mimiaga, Matthew J

2014-07-01

226

Induction of female-to-male sex change in the honeycomb grouper (Epinephelus merra) by 11-ketotestosterone treatments.  

PubMed

The honeycomb grouper, Epinephelus merra, is a protogynous hermaphrodite fish. Sex steroid hormones play key roles in sex change of this species. A significant drop in endogenous estradiol-17beta (E2) levels alone triggers female-to-male sex change, and the subsequent elevation of 11-ketotestosterone (11KT) levels correlates with the progression of spermatogenesis. To elucidate the role of an androgen in sex change, we attempted to induce female-to-male sex change by exogenous 11KT treatments. The 75-day 11KT treatment caused 100% masculinization of pre-spawning females. Ovaries of the control (vehicle-treated) fish had oocytes at various stages of oogenesis, while the gonads of the 11KT-treated fish had transformed into testes; these contained spermatogenic germ cells at various stages, including an accumulation of spermatozoa in the sperm duct. In the sex-changed fish, plasma levels of E2 were significantly low, while both testosterone (T) and 11KT were significantly increased. Our results suggest that 11KT plays an important role in sex change in the honeycomb grouper. Whether the mechanism of 11KT-induced female-to-male sex change acts through direct stimulation of spermatogenesis in the ovary or via the inhibition of estrogen synthesis remains to be clarified. PMID:16547407

Bhandari, Ramji Kumar; Alam, Mohammad Ashraful; Soyano, Kiyoshi; Nakamura, Masaru

2006-01-01

227

Production of all female progeny: evidence for the presence of the male sex determination factor on the Y chromosome.  

PubMed

The red flour beetle, Tribolium castaneum, follows an XX (female) and XY (male) sex determination system. Maternal supply of the protein Transformer (Tra) is required for XX insects to follow the female pathway. The nature and source of the signal that regulates male sex determination in XY beetles are not known. Parental RNAi-aided knockdown in expression of tra masculinizes genetic females (XX) that are fertile. The virgin females mated with these masculinized genetic females produced all female progeny. We present the genetic evidence to show that the factor responsible for male sex determination is present on the Y chromosome. These data also suggest that the Y chromosome in T. castaneum is not required for male fertility. PMID:24577442

Shukla, Jayendra Nath; Palli, Subba Reddy

2014-05-15

228

Insect sex chromosomes. VI. A presumptive hyperactivation of the male X chromosome in Acheta domesticus (L.).  

PubMed

The functional status of the X chromosome in Acheta domesticus has been analysed at the whole chromosome level on the basis of (1) 3H-thymidine autoradiography, (2) 5-BrdU/AO fluorescence microscopy (3) in vivo 5-BrdU incorporation and (4) 3H-UdR induced aberrations. The rationale of these techniques in relation to the functional aspect of the X chromosome is that the inactive X chromosome would (1) show asynchrony in DNA synthesis, (2) show differential fluorescence, (3) respond differentially to in vivo 5-BrdU treatment and (4) the active X chromosome would show aberrations when treated with 3H-Uridine. From the results, it appears that the X chromosomes in both male (XO) and female (XX) somatic cells of Acheta are euchromatic (active). Further, the single X in the male is transcriptionally as active as the two X chromosomes in the female. In other words, the single X in the male is hyperactive when compared with the single X in the female. From this it is inferred that the male X chromosome is differentially regulated in order to bring about an equalization of it's gene product(s) to that produced by both Xs in the female. Drosophila melanogaster has a comparable system of dosage compensation. Thus, Acheta is yet another insect showing evidence for an X chromosome regulatory mechanism of dosage compensation. Additionally, it is surmised that sex determination in Acheta is based on an autosomes/X chromosome balance mechanism. PMID:7172864

Rao, S R; Ali, S

1982-01-01

229

Breeding periodicity for male sea turtles, operational sex ratios, and implications in the face of climate change.  

PubMed

Species that have temperature-dependent sex determination (TSD) often produce highly skewed offspring sex ratios contrary to long-standing theoretical predictions. This ecological enigma has provoked concern that climate change may induce the production of single-sex generations and hence lead to population extirpation. All species of sea turtles exhibit TSD, many are already endangered, and most already produce sex ratios skewed to the sex produced at warmer temperatures (females). We tracked male loggerhead turtles (Caretta caretta) from Zakynthos, Greece, throughout the entire interval between successive breeding seasons and identified individuals on their breeding grounds, using photoidentification, to determine breeding periodicity and operational sex ratios. Males returned to breed at least twice as frequently as females. We estimated that the hatchling sex ratio of 70:30 female to male for this rookery will translate into an overall operational sex ratio (OSR) (i.e., ratio of total number of males vs females breeding each year) of close to 50:50 female to male. We followed three male turtles for between 10 and 12 months during which time they all traveled back to the breeding grounds. Flipper tagging revealed the proportion of females returning to nest after intervals of 1, 2, 3, and 4 years were 0.21, 0.38, 0.29, and 0.12, respectively (mean interval 2.3 years). A further nine male turtles were tracked for short periods to determine their departure date from the breeding grounds. These departure dates were combined with a photoidentification data set of 165 individuals identified on in-water transect surveys at the start of the breeding season to develop a statistical model of the population dynamics. This model produced a maximum likelihood estimate that males visit the breeding site 2.6 times more often than females (95%CI 2.1, 3.1), which was consistent with the data from satellite tracking and flipper tagging. Increased frequency of male breeding will help ameliorate female-biased hatchling sex ratios. Combined with the ability of males to fertilize the eggs of many females and for females to store sperm to fertilize many clutches, our results imply that effects of climate change on the viability of sea turtle populations are likely to be less acute than previously suspected. PMID:20497201

Hays, Graeme C; Fossette, Sabrina; Katselidis, Kostas A; Schofield, Gail; Gravenor, Mike B

2010-12-01

230

The balancing act: Exploring stigma, economic need and disclosure among male sex workers in Ho Chi Minh City, Vietnam.  

PubMed

In Vietnam, there is an emerging HIV epidemic among men who have sex with men (MSM). Male sex workers engage in high-risk sexual behaviours that make them particularly vulnerable to HIV infection. In 2010, 23 MSM in Ho Chi Minh City (HCMC) who recently received payment for sex with another man completed in-depth qualitative interviews exploring motivations for sex work, patterns of sex work disclosure and experiences of social stigma. Interviews were recorded, transcribed and translated into English and analysed using a qualitative descriptive approach. Low wages, unstable employment and family remittances were motivating factors for MSM in HCMC to sell sex. Participants described experiences of enacted and felt social stigma related to their involvement in sex work. In response, they utilised stigma management techniques aimed at concealment of involvement in sex work. Such strategies restricted sexual communication with non-paying sex partners and potentially limited their ability to seek social support from family and friends. Departing from decontextualized depictions of sex work disclosure, our findings describe how decisions to reveal involvement in sex work are shaped by social and structural factors such as social stigma, techniques to minimise exposure to stigma, economic imperatives and familial responsibilities. PMID:25555192

Closson, Elizabeth F; Colby, Donn J; Nguyen, Thi; Cohen, Samuel S; Biello, Katie; Mimiaga, Matthew J

2015-04-01

231

Antiretroviral Therapy as a Factor Protective against Anal Dysplasia in HIV-Infected Males Who Have Sex with Males  

PubMed Central

Objectives Chronic infection with oncogenic HPV genotype is associated with the development of anal dysplasia. Antiretroviral therapy (ART) has been shown to decrease the incidence of cervical carcinoma in women with HIV. We sought to: 1) describe the prevalence and grade of anal dysplasia and HPV infection in our study subjects; 2) analyze the grade of correlation between anal cytology, PCR of high-risk HPV, and histology; 3) identify the factors associated with the appearance of ?AIN2 lesions. Design Cross-sectional, prospective study. Methods A cohort of HIV-positive males (n?=?140, mean age ?=?37 years) who have sex with males (MSM) had epidemiological, clinical and analytical data collected. Anal mucosa samples were taken for cytology, HPV PCR genotyping, and anoscopy for histological analysis. Results Within the cohort, 77.1% were being treated with ART, 8.5% anoscopy findings were AIN2, and 11.4% carcinoma in situ; 74.2% had high-risk (HR), 59.7% low-risk (LR) HPV genotypes and 46.8% had both. The combination of cytology with PCR identifying HR-HPV better predicts the histology findings than either of these factors alone. Logistic regression highlighted ART as a protective factor against ?AIN2 lesions (OR: 0.214; 95%CI: 0.054–0.84). Anal/genital condylomas (OR: 4.26; 95%CI: 1.27–14.3), and HPV68 genotype (OR: 10.6; 95%CI: 1.23–91.47) were identified as risk factors. Conclusions In our cohort, ART has a protective effect against dysplastic anal lesions. Anal/genital warts and HPV68 genotype are predictors of ?AIN2 lesions. Introducing PCR HPV genotype evaluation improves screening success over that of cytology alone. PMID:24676139

Hidalgo-Tenorio, Carmen; Rivero-Rodriguez, Mar; Gil-Anguita, Concepción; Lopez De Hierro, Mercedes; Palma, Pablo; Ramírez-Taboada, Jessica; Esquivias, Javier; López-Ruz, Miguel Angel; Javier-Martínez, Rosario; Pasquau-Liaño, Juan

2014-01-01

232

The Role of Clitoral Anatomy in Female to Male Sex Reassignment Surgery  

PubMed Central

Introduction. Controversies on clitoral anatomy and its role in female sexual function still make clitoral reconstructive surgery very challenging. We evaluated the role of clitoral anatomic features in female to male sex reassignment surgery. Material and Methods. The study included 97 female transsexuals, aged from 18 to 41 years, who underwent single stage metoidioplasty between March 2008 and January 2013. The operative technique involved vaginectomy, the release of clitoral ligaments and urethral plate, urethroplasty by combining buccal mucosa graft and genital flaps, and scrotoplasty with insertion of testicle prostheses. Postoperative questionnaire was used to evaluate aesthetic, functional, and sexual outcome. Results. The mean followup was 30 months. The mean length of the neophallus was 7?cm, compared to mean preoperative length of the hypertrophied clitoris of 3.3?cm. Complications occurred in 27.84% of all patients, related mostly to urethroplasty. Voiding while standing was achieved in all cases. None of the patients had problems in sexual arousal, masturbation, or orgasms. Conclusion. Accurate knowledge of the clitoral anatomy, physiology, and neurovascular supply is crucial for a successful outcome of female to male sex reassignment surgery. Our approach appears to ensure overall satisfaction and high quality of sexual life. PMID:24982953

2014-01-01

233

HIV prevalence and risk behaviors among male clients of female sex workers in Yunnan, China  

PubMed Central

Objectives To assess the prevalence and risk factors of HIV among male clients of female sex workers in China. Methods Convenience sampling methods were used to recruit 315 clients using FSW-client and client-client networks. Subjects provided information on socio-demographic characteristics and sexual and drug behavior patterns. Blood samples were collected for HIV testing and urine samples for opiate testing. Results Overall HIV prevalence was 6.0%; among drug users it was 30.8%. 33.7% of respondents reported that they always use condoms in commercial sex and 63.5% that they used a condom in the last commercial sex episode. Drug use (OR: 6.1; 95% CI: 1.7–21.4) and lack of a regular sexual partner (OR: 6.3; 95% CI: 1.8–21.9) were significantly associated with HIV infection. Conclusions Clients of FSWs serve as potential bridges for HIV transmission from the high-risk FSWs to the low-risk general population, making them a key target for intervention. High HIV prevalence rates among clients in Kaiyuan is particularly alarming given their risk behavior patterns including high rates of partner exchange, low condom use rates, and drug using behaviors. Innovative interventions are needed to reduce the risk of HIV among clients and reduce the bridge of transmission to the general population. PMID:19730110

Jin, Xia; Smith, Kumi; Chen, Ray Y.; Ding, Guowei; Yao, Yan; Wang, Haibo; Qian, Han-Zhu; Chang, Dongfang; Wang, Guixiang; Wang, Ning

2009-01-01

234

Male-Dependent Doubly Uniparental Inheritance of Mitochondrial DNA and Female-Dependent Sex-Ratio in the Mussel Mytilus galloprovincialis  

Microsoft Academic Search

We have investigated sex ratio and mitochondrial DNA inheritance in pair-matings involving five female and five male individuals of the Mediterranean mussel Mytilus galloprovincialis. The percentage of male progeny varied widely among families and was found to be a characteristic of the female parent and independent of the male to which it was mated. Thus sex-ratio in Mytilus appears to

Carlos Saavedra; Maria-Isabel Reyerot; Eleftherios Zouros

235

MicroRNAs influence reproductive responses by females to male sex peptide in Drosophila melanogaster.  

PubMed

Across taxa, female behavior and physiology change significantly following the receipt of ejaculate molecules during mating. For example, receipt of sex peptide (SP) in female Drosophila melanogaster significantly alters female receptivity, egg production, lifespan, hormone levels, immunity, sleep, and feeding patterns. These changes are underpinned by distinct tissue- and time-specific changes in diverse sets of mRNAs. However, little is yet known about the regulation of these gene expression changes, and hence the potential role of microRNAs (miRNAs), in female postmating responses. A preliminary screen of genomic responses in females to receipt of SP suggested that there were changes in the expression of several miRNAs. Here we tested directly whether females lacking four of the candidate miRNAs highlighted (miR-279, miR-317, miR-278, and miR-184) showed altered fecundity, receptivity, and lifespan responses to receipt of SP, when mated once or continually to SP null or control males. The results showed that miRNA-lacking females mated to SP null males exhibited altered receptivity, but not reproductive output, in comparison to controls. However, these effects interacted significantly with the genetic background of the miRNA-lacking females. No significant survival effects were observed in miRNA-lacking females housed continually with SP null or control males. However, continual exposure to control males that transferred SP resulted in significantly higher variation in miRNA-lacking female lifespan than did continual exposure to SP null males. The results provide the first insight into the effects and importance of miRNAs in regulating postmating responses in females. PMID:25245794

Fricke, Claudia; Green, Darrell; Smith, Damian; Dalmay, Tamas; Chapman, Tracey

2014-12-01

236

MicroRNAs Influence Reproductive Responses by Females to Male Sex Peptide in Drosophila melanogaster  

PubMed Central

Across taxa, female behavior and physiology change significantly following the receipt of ejaculate molecules during mating. For example, receipt of sex peptide (SP) in female Drosophila melanogaster significantly alters female receptivity, egg production, lifespan, hormone levels, immunity, sleep, and feeding patterns. These changes are underpinned by distinct tissue- and time-specific changes in diverse sets of mRNAs. However, little is yet known about the regulation of these gene expression changes, and hence the potential role of microRNAs (miRNAs), in female postmating responses. A preliminary screen of genomic responses in females to receipt of SP suggested that there were changes in the expression of several miRNAs. Here we tested directly whether females lacking four of the candidate miRNAs highlighted (miR-279, miR-317, miR-278, and miR-184) showed altered fecundity, receptivity, and lifespan responses to receipt of SP, when mated once or continually to SP null or control males. The results showed that miRNA-lacking females mated to SP null males exhibited altered receptivity, but not reproductive output, in comparison to controls. However, these effects interacted significantly with the genetic background of the miRNA-lacking females. No significant survival effects were observed in miRNA-lacking females housed continually with SP null or control males. However, continual exposure to control males that transferred SP resulted in significantly higher variation in miRNA-lacking female lifespan than did continual exposure to SP null males. The results provide the first insight into the effects and importance of miRNAs in regulating postmating responses in females. PMID:25245794

Fricke, Claudia; Green, Darrell; Smith, Damian; Dalmay, Tamas; Chapman, Tracey

2014-01-01

237

The Transcriptome of Lutzomyia longipalpis (Diptera: Psychodidae) Male Reproductive Organs  

PubMed Central

Background It has been suggested that genes involved in the reproductive biology of insect disease vectors are potential targets for future alternative methods of control. Little is known about the molecular biology of reproduction in phlebotomine sand flies and there is no information available concerning genes that are expressed in male reproductive organs of Lutzomyia longipalpis, the main vector of American visceral leishmaniasis and a species complex. Methods/Principal Findings We generated 2678 high quality ESTs (“Expressed Sequence Tags”) of L. longipalpis male reproductive organs that were grouped in 1391 non-redundant sequences (1136 singlets and 255 clusters). BLAST analysis revealed that only 57% of these sequences share similarity with a L. longipalpis female EST database. Although no more than 36% of the non-redundant sequences showed similarity to protein sequences deposited in databases, more than half of them presented the best-match hits with mosquito genes. Gene ontology analysis identified subsets of genes involved in biological processes such as protein biosynthesis and DNA replication, which are probably associated with spermatogenesis. A number of non-redundant sequences were also identified as putative male reproductive gland proteins (mRGPs), also known as male accessory gland protein genes (Acps). Conclusions The transcriptome analysis of L. longipalpis male reproductive organs is one step further in the study of the molecular basis of the reproductive biology of this important species complex. It has allowed the identification of genes potentially involved in spermatogenesis as well as putative mRGPs sequences, which have been studied in many insect species because of their effects on female post-mating behavior and physiology and their potential role in sexual selection and speciation. These data open a number of new avenues for further research in the molecular and evolutionary reproductive biology of sand flies. PMID:22496818

Bretãs, Jorge A. C.; Mazzoni, Camila J.; Souza, Nataly A.; Albano, Rodolpho M.; Wagner, Glauber; Davila, Alberto M. R.; Peixoto, Alexandre A.

2012-01-01

238

Useless hearing in male Emblemasoma auditrix (Diptera, Sarcophagidae)--a case of intralocus sexual conflict during evolution of a complex sense organ?  

PubMed

Sensory modalities typically are important for both sexes, although sex-specific functional adaptations may occur frequently. This is true for hearing as well. Consequently, distinct behavioural functions were identified for the different insect hearing systems. Here we describe a first case, where a trait of an evolutionary novelty and a highly specialized hearing organ is adaptive in only one sex. The main function of hearing of the parasitoid fly Emblemasoma auditrix is to locate the host, males of the cicada species Okanagana rimosa, by their calling song. This task is performed by female flies, which deposit larvae into the host. We show that male E. auditrix possess a hearing sense as well. The morphology of the tympanal organ of male E. auditrix is rather similar to the female ear, which is 8% broader than the male ear. In both sexes the physiological hearing threshold is tuned to 5 kHz. Behavioural tests show that males are able to orient towards the host calling song, although phonotaxis often is incomplete. However, despite extensive observations in the field and substantial knowledge of the biology of E. auditrix, no potentially adaptive function of the male auditory sense has been identified. This unique hearing system might represent an intralocus sexual conflict, as the complex sense organ and the behavioural relevant neuronal network is adaptive for only one sex. The correlated evolution of the sense organ in both sexes might impose substantial constraints on the sensory properties of the ear. Similar constraints, although hidden, might also apply to other sensory systems in which behavioural functions differ between sexes. PMID:24489872

Lakes-Harlan, Reinhard; Devries, Thomas; Stölting, Heiko; Stumpner, Andreas

2014-01-01

239

Partners met via sex parties present significantly greater odds for condomless anal sex among MSM: an event-level analysis of venues where male partners are met.  

PubMed

One hundred forty-seven men who have sex with men completed time-line follow-back interviews about the venues where they met their male partners (n = 1180 sexual events with first-time partners, <30 days). We ran multivariate models to determine the association between venues and condomless anal sex (CAS). After adjusting for known correlates of CAS, partners met at sex parties presented significantly greater odds for CAS compared with meeting a partner at a gay bar/club (adjusted odds ratio = 0.44), online (adjusted odds ratio = 0.42), bathhouse (adjusted odds ratio = 0.35), or via "other" venues (adjusted odds ratio = 0.35), all P < 0.01. These findings highlight the need to develop innovative HIV/sexually transmitted infection prevention initiatives for men who attend sex parties. PMID:25226209

Grov, Christian; Rendina, H J; Ventuneac, Ana; Parsons, Jeffrey T

2014-12-15

240

In Peru, reporting male sex partners imparts significant risk of incident HIV/STI infection: all men engaging in same-sex behavior need prevention services  

PubMed Central

Background Detailed information on the sexual behavior of bisexual, non-gay identified men and the relationship between same-sex behavior and HIV/STI incidence are limited. This study provides information on the sexual behavior with male partners of non-gay identified men in urban, coastal Peru and the relationship of this behavior with HIV/STI incidence. Methods We analyzed data from 2146 non-gay identified men with a baseline and then two years of annual follow-up, including detailed information on sexual behavior with up to 5 sex partners, to determine characteristics associated with bisexual behavior. Discrete time proportional hazards models were used to determine the effect of self-reported sex with men on subsequent HIV/STI incidence. Results Over the three study visits, sex with a man was reported by 18.9% of men, 90% of whom also reported sex with a female partner. At baseline, reported bisexual behavior was associated with other sexual risk behaviors such as exchanging sex for money and increased risk of HIV, HSV-2, and gonorrhea. The number of study visits in which recent sex with men was reported was positively correlated with risk of other sexual risk behaviors and incident HIV, HSV-2, and gonorrhea. Recent sex with a man was associated with increased HIV/STI incidence, HR 1.79 (95% CI 1.19 – 2.70), after adjusting for socio-demographics and other sexual risk behaviors. Conclusions Given the prevalence of recent sex with men and the relationship of this behavior with HIV/STI incidence, interventions with non-gay identified men who have sex with men and their partners are warranted. PMID:23965772

Konda, Kelika A.; Lescano, Andres G.; Celentano, David D.; Hall, Eric; Montano, Silvia M.; Kochel, Tadeusz J.; Coates, Thomas J.; Cáceres, Carlos F.

2013-01-01

241

A comparative study of renal function in male and female spiny mice – sex specific responses to a high salt challenge  

PubMed Central

Background There is a significant body of evidence to suggest that hormone levels, receptor density and structural differences between males and females can significantly alter renal hemodynamics. We compared the renal hemodynamic and excretory profile of female and male spiny mice under baseline conditions and in response to a high-NaCl diet. Methods Adult male and female spiny mice were fed either a normal or high salt diet for 7 days. Renal excretory profile was obtained from 24 h urine samples, and renal hemodynamic measurements using anaesthetised renal clearance techniques. Kidneys were excised, weighed and frozen for qPCR analysis. Results Under basal conditions, conscious and anaesthetised renal functions were similar between male and female spiny mice when adjusted for body weights. Male and female spiny mice on the high-NaCl diet had significantly greater GFR than sex matched controls (PDIET < 0.001). However the magnitude of the effect of salt was sex dependent (PSEX < 0.001; PINT < 0.01). Male spiny mice showed a greater increase in GFR (84% higher than normal salt males) compared to females (33% higher than normal salt females), despite similar increases in renal plasma flow. In response to 7 days of high salt diet, female spiny mice showed a greater increase in 24-hour water consumption (45% more) and urinary output (50% more) compared to males (PINT < 0.01). These sex differences could not be explained by differences in renal expression of the V2R or AQP3 channel. Conclusion These studies have identified major differences between male and female spiny mice in their renal response to a high-NaCl load suggesting that renal hemodynamics may be differentially regulated for the sexes. PMID:24321563

2013-01-01

242

[Effect of the hereditary characteristics of male blue foxes Alopex lagopus L. on the sex ratio of their offspring].  

PubMed

Family analysis of a commercial population of the blue fox (the Pushkinskoe Breeding Fur Farm, Moscow oblast) with respect to secondary sex ratio has been performed. The offspring of each individual male or female involved in crossing between 1984 and 1988 was analyzed. The study of all families formed by every male and every female has made it possible to determine a group of "outstanding" fathers (23 out of 287 males), whose offspring was predominantly male (62.1% of the offspring were males, versus 53.9% in the total population). The results of subsequent detailed study on the pedigrees of male blue foxes in whose offspring the sex ratio significantly deviates from 1:1 indicate that this character is transmitted from fathers to sons without the deterioration of other commercially valuable characters. It is presumed that the significant deviation of sex ratio from 1:1 in the offspring of some male blue foxes is determined by genetic factors. PMID:15865299

Beketov, S V; Kashtanov, S N

2005-03-01

243

B-chromosomes and male-biased sex ratio with paternal inheritance in the fairy shrimp Branchipus schaefferi (Crustacea, Anostraca).  

PubMed

This study reports on male-biased sex ratios in west Mediterranean populations of the freshwater anostracan Branchipus schaefferi (Crustacea, Anostraca, Branchipodidae), in contrast to populations elsewhere. Crossing experiments over several generations indicate a clear paternal inheritance of the trait, possibly with a dosage effect. Various mechanisms which may underlie this phenomenon are discussed, the most plausible being the presence of one or more supernumerary ('B') chromosomes--as evidenced by karyological observations--interfering with sex determination and probably having an accumulation mechanism in male individuals. PMID:11986871

Beladjal, L; Vandekerckhove, T T M; Muyssen, B; Heyrman, J; de Caesemaeker, J; Mertens, J

2002-05-01

244

[Body dissatisfaction among female and male adolescents: comparing prevalence, predictors, and consequences between the sexes].  

PubMed

As part of the POPS study (Potsdam prevention of eating disorders) 300 adolescents aged between 10 and 13 years completed questionnaires measuring satisfaction with weight and muscles, body change strategies and disturbed eating behavior. More than half of the girls and a third of the boys are dissatisfied with their weight. Nearly 70% of the male participants were unhappy with their muscles. Both forms of body dissatisfaction are influenced by similar sociocultural and psychological factors. While weight dissatisfaction leads to weight reduction strategies and disturbed eating, muscle dissatisfaction results in muscle enhancement methods. Potential harmful consequences of excessive muscle building techniques are discussed. The data emphasize the need for a sex-specific investigation of body dissatisfaction and its consequences. Body image aspects relevant to boys should be added to intervention and prevention approaches. PMID:21614841

Mohnke, Sebastian; Warschburger, Petra

2011-01-01

245

Behavioural evidence of male volatile pheromones in the sex-role reversed wolf spiders Allocosa brasiliensis and Allocosa alticeps  

NASA Astrophysics Data System (ADS)

The use of chemical signals in a sexual context is widespread in the animal kingdom. Most studies in spiders report the use of female pheromones that attract potential sexual partners. Allocosa brasiliensis and Allocosa alticeps are two burrowing wolf spiders that show sex-role reversal. Females locate male burrows and initiate courtship before males perform any detectable visual or vibratory signal. So, females of these species would be detecting chemical or mechanical cues left by males. Our objective was to explore the potential for male pheromones to play a role in mate detection in A. brasiliensis and A. alticeps. We designed two experiments. In Experiment 1, we tested the occurrence of male contact pheromones by evaluating female courtship when exposed to empty burrows constructed by males or females (control). In Experiment 2, we tested the existence of male volatile pheromones by evaluating female behaviour when exposed to artificial burrows connected to tubes containing males, females or empty tubes (control). Our results suggest the occurrence of male volatile pheromones that trigger female courtship in both Allocosa species. The sex-role reversal postulated for these wolf spiders could be driving the consequent reversal in typical pheromone-emitter and detector roles expected for spiders.

Aisenberg, Anita; Baruffaldi, Luciana; González, Macarena

2010-01-01

246

Intervention of D-glucose ameliorates the toxicity of streptozotocin in accessory sex organs of rat  

SciTech Connect

Streptozotocin (STZ) is a naturally occurring compound isolated from Streptomyces achromogens. It is used extensively for inducing diabetes in experimental animals. Diabetes mellitus is known to have proven adverse effects on male sexual organs and their reproductive functions. The atrophy of prostate gland and other organs of the genitourinary tract were observed in experimental diabetic animals. STZ exhibits a structural resemblance to D-glucose due to the presence of sugar moiety in its structure. Pancreatic {beta}-cells mainly contain GLUT1 and GLUT2 glucose transporters. Possibly due to structural resemblance, STZ and D-glucose, share a common recognition site for entry into the {beta}-cells. The objective of the present study is to evaluate the effect of D-glucose on STZ-induced toxicity in accessory sex organs of male rats. Animals were kept on overnight fasting. One group received vehicle and served as negative control, while all other groups were given STZ (45 mg/kg). Animals that received only STZ served as positive control. The effect of D-glucose was studied on STZ treated animals with different dosage of D-glucose (250, 500, 1000 and 2000 mg/kg). Restoration of body weight, plasma glucose and plasma insulin was evident only at 1000 and 2000 mg/kg of D-glucose. The protective effect of D-glucose is evident only when it is administered simultaneously with STZ. In the present investigation, we report that simultaneous administration of D-glucose along with STZ ameliorates STZ-induced toxicity. This is evident from the restoration of accessory sex organ's weight, cellular morphology as well as insulin level.

Vikram, A.; Tripathi, D.N.; Ramarao, P. [Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, Punjab-160062 (India); Jena, G.B. [Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Sector-67, S.A.S. Nagar, Punjab-160062 (India)], E-mail: gbjena@gmail.com

2008-01-01

247

Non-monogamy and sexual relationship quality among same-sex male couples.  

PubMed

Relationship arrangements about sex with outside partners are common among gay couples, and meaningful distinctions in psychological and behavioral health correlates have been found among nonmonogamous agreement types. The goal of this study was to investigate the relationship between sexual agreements and partners' sexual relationship quality. Data were collected from both members of 161 gay male couples (n = 322 individuals). Couples were categorized as monogamous (52.8%), open (13.0%), monogamish (14.9%), and discrepant (19.3%). We used the actor-partner interdependence model (APIM) to assess associations of relationship arrangement with four aspects of sexual relationship quality: sexual satisfaction, sexual communication, sexual jealousy, and the occurrence of at-least weekly sex between main partners. We found that sexual arrangements were not associated with sexual satisfaction, communication, or frequency. However, monogamous men reported significantly higher levels of sexual jealousy. Our findings indicate that gay men engage in a range of relationship agreements, and nonmonogamous agreements are associated with levels of sexual relationship quality equivalent to monogamous agreements. PMID:22906124

Parsons, Jeffrey T; Starks, Tyrel J; Gamarel, Kristi E; Grov, Christian

2012-10-01

248

The Role of Androgens in Male Pregnancy and Female Competitive Behavior in a Sex Role Reversed Pipefish  

E-print Network

, 1967a). In contrast to androgens, a syngnathid MIS may only be present in the circulation of males for very brief periods immediately preceding spawning, as the production of mature spermatozoa in several species seems to be halted until stimulated... fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY December 2011 Major Subject: Biology The Role of Androgens in Male Pregnancy and Female Competitive Behavior in a Sex Role Reversed...

Scobell, Sunny Kay

2012-02-14

249

The significance of blends of two sex pheromone components on the behavior of male Spodoptera litura F. (Lepidoptera: Noctuidae)  

Microsoft Academic Search

Behavioral responses of maleSpodoptera litura to the female sex pheromone components, (Z, E)-9, 11-tetradecadienyl acetate (compound A) and (Z, E)-9, 12-tetradecadienyl acetate (compound B), and mixtures of compounds A and B were analyzed in the laboratory. Male orientation\\u000a flight in a wind tunnel was induced by a lure dispenser onto which 1.110?3 ng of a mixture (A?B=10?1) was absorbed, while

Kenjiro Kawasaki

1986-01-01

250

Green Light Synergistally Enhances Male Sweetpotato Weevil Response to Sex Pheromone  

PubMed Central

Sweetpotato, commercially grown in over 100 countries, is one of the ten most important staple crops in the world. Sweetpotato weevil is a major pest of sweetpotato in most areas of cultivation, the feeding of which induces production in the sweetpotato root of extremely bitter tasting and toxic sesquiterpenes which can render the sweetpotato unfit for consumption. A significant step towards improved management of this weevil species was the identification of a female-produced sex pheromone [(Z)-3-dodecenyl (E)-2-butenoate] to which males are highly attracted. Reported here are results of research that documents a nearly 5-fold increase in male sweetpotato weevil catch in traps baited with this pheromone and a green light provided by a solar-powered, light-emitting diode (LED). The combination of olfactory and night-visible visual cues significantly enhanced trap effectiveness for this nighttime-active insect species. These results provide promise for improved sweetpotato weevil detection and suppression in mass trapping programs. PMID:24675727

McQuate, Grant T.

2014-01-01

251

Male mate choice relies on major histocompatibility complex class I in a sex-role-reversed pipefish.  

PubMed

Mate choice for compatible genes is often based on genes of the major histocompatibility complex (MHC). Although MHC-based mate choice is commonly observed in female choice, male mate choice remains elusive. In particular, if males have intense paternal care and are thus the choosing sex, male choice for females with dissimilar MHC can be expected. Here, we investigated whether male mate choice relies on MHC class I genes in the sex-role reversed pipefish Syngnathus typhle. In a mate choice experiment, we determined the relative importance of visual and olfactory cues by manipulating visibility and olfaction. We found that pipefish males chose females that maximize sequence-based amino acid distance between MHC class I genotypes in the offspring when olfactory cues were present. Under visual cues, large females were chosen, but in the absence of visual cues, the choice pattern was reversed. The use of sex-role reversed species thus revealed that sexual selection can lead to the evolution of male mate choice for MHC class I genes. PMID:24725009

Roth, O; Sundin, J; Berglund, A; Rosenqvist, G; Wegner, K M

2014-05-01

252

Results of a randomised trial of male condom promotion among Madagascar sex workers  

PubMed Central

Objectives: To test the effect of supplementing peer promotion of male condom use with clinic based counselling, measured in terms of STI prevalence and reported male condom use. Methods: 1000 female sex workers in Madagascar were randomised to two study arms: peer education supplemented by individual risk reduction counselling by a clinician (peer + clinic) versus condom promotion by peer educators only (peer only). STI testing was conducted at baseline and 6 months. Behavioural interviews were administered at baseline, 2, 4, and 6 months. Results: At baseline, women in the peer only arm had prevalences of 16.0%, 23.6%, and 12.1% for chlamydia, gonorrhoea, and trichomoniasis respectively, with an aggregate prevalence of 38.2%. Baseline STI prevalences for the peer + clinic arm were slightly lower and 34.1% in aggregate. At 6 months, aggregate STI prevalence increased in the peer only arm to 41.4%, whereas the aggregate prevalence diminished slightly to 32.1% in the peer + clinic arm. In logistic regression analyses, the estimated odds ratios (ORs) for chlamydia, gonorrhoea, trichomoniasis, and aggregate STI were 0.7 (95% confidence interval 0.4 to 1.0), 0.7 (0.5 to 1.0), 0.8 (0.6 to 1.2), and 0.7 (0.5 to 0.9) respectively, comparing the peer + clinic arm with the peer only arm. The logistic regression OR for reported condom use with clients in the past 30 days increased from 1.1 at 2 months to 1.8 at 6 months, comparing the peer + clinic arm with the peer only arm, and was 1.4 overall (1.1 to 1.8). Adjustment for baseline factors changed the regression results little. Conclusions: The impact of male condom promotion on behaviour can be heightened through more concentrated counselling on risk reduction. Persistently high STI prevalence despite increases in reported condom use by sex workers supports the need for multidimensional control programmes. PMID:15800098

Feldblum, P; Hatzell, T; Van Damme, K; Nasution, M; Rasamindrakotroka, A; Grey, T

2005-01-01

253

Anatomical organization of antennal-lobe glomeruli in males and females of the scarab beetle Holotrichia diomphalia (Coleoptera: Melolonthidae).  

PubMed

The glomerular organization of the primary olfactory brain center, the antennal lobe, was studied in males and females of Holotrichia diomphalia adults using serial histological sections labeled by the reduced silver-stain technique. The results revealed an apparent sexual dimorphism. Whereas an enlarged cap-shaped glomerulus was found at the antennal nerve entrance into the antennal lobe in males, no such unit was present in females. Also the size of the antennal lobe differed between the sexes, the antennal lobe of males being larger than that of females. We estimated the total number of glomeruli at approximately 60 units in the female antennal lobe. In males, we could discriminate only those glomeruli that were located in the anterior area of the antennal lobe. PMID:21889404

Hu, Ji-Hua; Wang, Zhi-Ying; Sun, Fan

2011-09-01

254

Male-only care and classical polyandry in birds: phylogeny, ecology and sex differences in remating opportunities.  

PubMed Central

It has been argued recently that the combination of male-only parental care and classical polyandry in birds is the most interesting and yet the least understood of all avian breeding systems. Despite a huge number of hypotheses, careful comparative analyses have repeatedly failed to identify consistent ecological differences between species showing male-only care and closely related species showing other patterns of care. This has led to the suggestion that such analyses fail because the crucial differences are between ancient lineages rather than between closely related species. Here, therefore, I use comparisons between families to test three well-known hypotheses: that male-only care is associated with: (i) a low rate of fecundity; (ii) large egg size relative to female size; or (iii) female-biased opportunities for remating. Families showing male-only care do not differ from families showing female-only care with respect to rate of fecundity or relative egg size. There is, however, a significant difference between these two groups of families with respect to an index of remating opportunities, nesting density. Families showing female-only care nest at high density, while those showing male-only care nest at very low density. This is one of the first times a consistent ecological correlate has been identified for male-only care in birds. It suggests that female-only care arises (or persists) in families where remating opportunities are abundant for both sexes, whereas male-only care arises (or persists) in families where remating opportunities are rare for both sexes and particularly scarce for males. This in turn suggests that sex differences in remating opportunities are the key ecological factor in determining male-only care and classical polyandry in birds. PMID:11958697

Owens, Ian P F

2002-01-01

255

B-chromosomes and male-biased sex ratio with paternal inheritance in the fairy shrimp Branchipus schaefferi (Crustacea, Anostraca)  

Microsoft Academic Search

This study reports on male-biased sex ratios in west Mediterranean populations of the freshwater anostracan Branchipus schaefferi (Crustacea, Anostraca, Branchipodidae), in contrast to populations elsewhere. Crossing experiments over several generations indicate a clear paternal inheritance of the trait, possibly with a dosage effect. Various mechanisms which may underlie this phenomenon are discussed, the most plausible being the presence of one

L Beladjal; T T M Vandekerckhove; B Muyssen; J Heyrman; J de Caesemaeker; J Mertens

2002-01-01

256

Differential Suicide Rates in Typologies of Child Sex Offenders in a 6-year Consecutive Cohort of Male Suicides  

Microsoft Academic Search

Earlier research identified 3 typologies of Child Sex Offenders [CSO] with high rates of suicide. To test this finding suicide rates of 3 types of CSO were compared in a 6-year cohort of regional suicides. All male suicides were identified from Coroners” inquest files and CSO data drawn from police records to calculate CSO suicide rates. The results show that

Colin Pritchard; Elizabeth King

2005-01-01

257

Have Sex Differences in Spatial Ability Evolved from Male Competition for Mating and Female Concern for Survival?  

ERIC Educational Resources Information Center

Drawing on the theoretical and empirical foundations of two evolutionary models, we argue that, among humans and other mammals, a twofold selection process would parsimoniously account for sex-linked advantages in spatial contexts. In males, a superiority for both solving navigation-related spatial problems and understanding physical principles…

Ecuyer-Dab, Isabelle; Robert, Michele

2004-01-01

258

Sex hormone changes induced by the parasite lead to feminization of the male host in murine Taenia crassiceps cysticercosis  

Microsoft Academic Search

Female mice are more susceptible to Taenia crassiceps (TC) infection than males. However, after a month parasite load increases massively in both genders reaching thousands of parasites per host. The possibility of hormonal changes in the infected mice was envisaged. Sex hormones levels were assayed after different periods of infection, the parasites present in the peritoneal cavity were collected and

C. Larralde; J. Morales; I. Terrazas; T. Govezensky; M. C. Romano

1995-01-01

259

Sex ratio and spatial distribution of male and female Antennaria dioica (Asteraceae) plants  

Microsoft Academic Search

Sex ratio, sex spatial distribution and sexual dimorphism in reproduction and arbuscular mycorrhizal colonisation were investigated in the dioecious clonal plant Antennaria dioica (Asteraceae). Plants were monitored for five consecutive years in six study plots in Oulanka, northern Finland. Sex ratio, spatial distribution of sexes, flowering frequency, number of floral shoots and the number and weight of inflorescences were recorded.

Sandra Varga; Minna-Maarit Kytöviita

2011-01-01

260

Discriminating males and unpredictable females: males differentiate self-similar facial cues more than females in the judgment of opposite-sex attractiveness.  

PubMed

Attractiveness judgment in the context of mate preferences is thought to reflect an assessment of mate quality in relation to an absolute scale of genetic fitness and a relative scale of self-similarity. In this study, subjects judged the attractiveness and trustworthiness of faces in composite images that were manipulated to produce self-similar (self-resemblance) and dissimilar (other-resemblance) images. Males differentiated between self- and other-resemblance as well as among different degrees of self-resemblance in their attractiveness ratings; females did not. Specifically, in Experiment 1, using a morphing technique, we created previously unseen face images possessing different degrees (0%, 30%, 40%, or 50%) of incorporation of the subject's images (different degrees of self-resemblance) and found that males preferred images that were closer to average (0%) rather than more self-similar, whereas females showed no preference for any degree of self-similarity. In Experiment 2, we added a pro-social question about trustworthiness. We replicated the Experiment 1 attractiveness rating results and further found that males differentiated between self- and other-resemblance for the same degree of composites; women did not. Both males and females showed a similar preference for self-resemblances when judging trustworthiness. In conclusion, only males factored self-resemblance into their attractiveness ratings of opposite-sex individuals in a manner consistent with cues of reproductive fitness, although both sexes favored self-resemblance when judging trustworthiness. PMID:24594644

Zhuang, Jin-Ying; Zhang, Sen; Xu, Jing; Hu, Die

2014-01-01

261

Changing seasonality and phenological responses of free-living male arctic ground squirrels: the importance of sex  

PubMed Central

Many studies have addressed the effects of climate change on species as a whole; however, few have examined the possibility of sex-specific differences. To understand better the impact that changing patterns of snow-cover have on an important resident Arctic mammal, we investigated the long-term (13 years) phenology of hibernating male arctic ground squirrels living at two nearby sites in northern Alaska that experience significantly different snow-cover regimes. Previously, we demonstrated that snow-cover influences the timing of phenological events in females. Our results here suggest that the end of heterothermy in males is influenced by soil temperature and an endogenous circannual clock, but timing of male emergence from hibernation is influenced by the timing of female emergence. Males at both sites, Atigun and Toolik, end heterothermy on the same date in spring, but remain in their burrows while undergoing reproductive maturation. However, at Atigun, where snowmelt and female emergence occur relatively early, males emerge 8 days earlier than those at Toolik, maintaining a 12-day period between male and female emergence found at each site, but reducing the pre-emergence euthermic period that is critical for reproductive maturation. This sensitivity in timing of male emergence to female emergence will need to be matched by phase shifts in the circannual clock and responsiveness to environmental factors that time the end of heterothermy, if synchrony in reproductive readiness between the sexes is to be preserved in a rapidly changing climate. PMID:23836786

Sheriff, Michael J.; Richter, Melanie M.; Buck, C. Loren; Barnes, Brian M.

2013-01-01

262

Neonatal testosterone partially organizes sex differences in stress-induced emotionality in mice  

PubMed Central

Major depressive disorder (MDD) is a debilitating disorder of altered mood regulation. Despite well established sex differences in MDD prevalence, the mechanism underlying the increased female vulnerability remains unknown. Although evidence suggests an influence of adult circulating hormone levels on mood (i.e. activational effects of hormones), MDD prevalence is consistently higher in women across life stages (and therefore hormonal states), suggesting that additional underlying structural or biological differences place women at higher risk. Studies in human subjects and in rodent models suggest a developmental origin for mood disorders, and interestingly, a developmental process also establishes sex differences in the brain. Hence, based on these parallel developmental trajectories, we hypothesized that a proportion of the female higher vulnerability to MDD may originate from the differential organization of mood regulatory neural networks early in life (i.e. organizational effects of hormones). To test this hypothesis in a rodent system, we took advantage of a well-established technique used in the field of sexual differentiation (neonatal injection with testosterone) to masculinize sexually dimorphic brain regions in female mice. We then investigated adult behavioral consequences relating to emotionality by comparing neonatal testosterone-treated females to normal males and females. Under baseline/trait conditions, neonatal testosterone treatment of female mice did not influence adult emotionality, but masculinized adult locomotor activity, as revealed by the activational actions of hormones. Conversely, the increased vulnerability of female mice to develop high emotionality following unpredictable chronic mild stress (UCMS) was partially masculinized by neonatal testosterone exposure, with no effect on post-UCMS locomotion. The elevated female UCMS-induced vulnerability did not differ between adult hormone treated groups. These results demonstrate that sex differences in adult emotionality in mice are partially caused by the organizational effects of sex hormones during development, hence supporting a developmental hypothesis of the human adult female prevalence of MDD. PMID:22394611

Seney, Marianne L.; Walsh, Christopher; Stolakis, Ryan; Sibille, Etienne

2012-01-01

263

Wolbachia is not all about sex: male-feminizing Wolbachia alters the leafhopper Zyginidia pullula transcriptome in a mainly sex-independent manner  

PubMed Central

Wolbachia causes the feminization of chromosomally male embryos in several species of crustaceans and insects, including the leafhopper Zyginidia pullula. In contrast to the relatively well-established ecological aspects of male feminization (e.g., sex ratio distortion and its consequences), the underlying molecular mechanisms remain understudied and unclear. We embarked on an exploratory study to investigate the extent and nature of Wolbachia's effect on gene expression pattern in Z. pullula. We sequenced whole transcriptomes from Wolbachia-infected and uninfected adults. 18147 loci were assembled de novo, including homologs of several Drosophila sex determination genes. A number of transcripts were flagged as candidate Wolbachia sequences. Despite the resemblance of Wolbachia-infected chromosomal males to uninfected and infected chromosomal females in terms of sexual morphology and behavior, principal component analysis revealed that gene expression patterns did not follow these sexual phenotype categories. The principal components generated by differentially expressed genes specified a strong sex-independent Wolbachia effect, followed by a weaker Wolbachia-sexual karyotype interaction effect. Approaches to further examine the molecular mechanism of Wolbachia-host interactions have been suggested based on the presented findings. PMID:25225494

Asgharian, Hosseinali; Chang, Peter L.; Mazzoglio, Peter J.; Negri, Ilaria

2014-01-01

264

Wolbachia is not all about sex: male-feminizing Wolbachia alters the leafhopper Zyginidia pullula transcriptome in a mainly sex-independent manner.  

PubMed

Wolbachia causes the feminization of chromosomally male embryos in several species of crustaceans and insects, including the leafhopper Zyginidia pullula. In contrast to the relatively well-established ecological aspects of male feminization (e.g., sex ratio distortion and its consequences), the underlying molecular mechanisms remain understudied and unclear. We embarked on an exploratory study to investigate the extent and nature of Wolbachia's effect on gene expression pattern in Z. pullula. We sequenced whole transcriptomes from Wolbachia-infected and uninfected adults. 18147 loci were assembled de novo, including homologs of several Drosophila sex determination genes. A number of transcripts were flagged as candidate Wolbachia sequences. Despite the resemblance of Wolbachia-infected chromosomal males to uninfected and infected chromosomal females in terms of sexual morphology and behavior, principal component analysis revealed that gene expression patterns did not follow these sexual phenotype categories. The principal components generated by differentially expressed genes specified a strong sex-independent Wolbachia effect, followed by a weaker Wolbachia-sexual karyotype interaction effect. Approaches to further examine the molecular mechanism of Wolbachia-host interactions have been suggested based on the presented findings. PMID:25225494

Asgharian, Hosseinali; Chang, Peter L; Mazzoglio, Peter J; Negri, Ilaria

2014-01-01

265

Sex hormone receptors in the hypothalamus and their role in sexual differentiation of the male rat brain  

SciTech Connect

In this investigation, changes in the level of receptors for sex hormones in the hypothalamus and cerebral cortex of male rats were studied on the first through fifth days of postnatal life, and the results obtained were compared with the levels of luteinizing hormone and sex hormones in the peripheral blood in order to discover any correlation between these parameters. 2,4,6,7,-/sup 3/H-estradiol-17..beta.. and 1,2,6,7-/sup 3/H-testosterone were used as labeled hormones. The values of the association constant and concentration of specific binding sites for estradiol and testosterone in hypothalamus and cerebral cortex of male rats during neonatal development is shown. It is found that in male rats on the first day after birth, receptors for estradiol and testosterone are present and they enable the action both of the testicular hormone and that of estradiol to be realized.

Shishkina, I.V.; Babichev, V.N.; Ozol', L.Yu.

1986-09-01

266

CHALLENGES IN BIODEGRADATION OF TRACE ORGANIC CONTAMINANTS-GASOLINE OXYGENATES AND SEX HORMONES  

EPA Science Inventory

Advances in analytical methods have led to the identification of several classes of organic chemicals that are associated with adverse environmental impacts. Two such classes of organic chemicals, gasoline oxygenates and sex hormones, are used to illustrate challenges associated ...

267

Effects of Vomeronasal Organ Removal on Olfactory Sex Discrimination and Odor Preferences of Female Ferrets  

Microsoft Academic Search

Previous research suggests that body odorants, including anal scents and urinary odors, contribute to sex discrimination and mate identification in European ferrets of both sexes. We assessed the possible role of the vomeronasal organ (VNO) in these functions by surgically removing the organ bilaterally in sexually experienced female ferrets. Lesioned (VNOx) and sham-oper- ated control (VNOi) females reliably discriminated between

S. K. Woodley; A. L. Cloe; P. Waters; M. J. Baum

2004-01-01

268

Exogenous application of estradiol to eggs unexpectedly induces male development in two turtle species with temperature-dependent sex determination.  

PubMed

Steroid hormones affect sex determination in a variety of vertebrates. The feminizing effects of exposure to estradiol and the masculinizing effects of aromatase inhibition during development are well established in a broad range of vertebrate taxa, but paradoxical findings are occasionally reported. Four independent experiments were conducted on two turtle species with temperature-dependent sex determination (Chrysemys picta and Chelydra serpentina) to quantify the effects of egg incubation temperature, estradiol, and an aromatase inhibitor on offspring sex ratios. As expected, the warmer incubation temperatures induced female development and the cooler temperatures produced primarily males. However, application of an aromatase inhibitor had no effect on offspring sex ratios, and exogenous applications of estradiol to eggs produced male offspring across all incubation temperatures. These unexpected results were remarkably consistent across all four experiments and both study species. Elevated concentrations of estradiol could interact with androgen receptors or inhibit aromatase expression, which might result in relatively high testosterone concentrations that lead to testis development. These findings add to a short list of studies that report paradoxical effects of steroid hormones, which addresses the need for a more comprehensive understanding of the role of sex steroids in sexual development. PMID:24954686

Warner, Daniel A; Addis, Elizabeth; Du, Wei-guo; Wibbels, Thane; Janzen, Fredric J

2014-09-15

269

Sex Differences in Liver Toxicity—Do Female and Male Human Primary Hepatocytes React Differently to Toxicants In Vitro?  

PubMed Central

There is increasing amount of evidence for sex variation in drug efficiency and toxicity profiles. Women are more susceptible than men to acute liver injury from xenobiotics. In general, this is attributed to sex differences at a physiological level as well as differences in pharmacokinetics and pharmacodynamics, but neither of these can give a sufficient explanation for the diverse responses to xenobiotics. Existing data are mainly based on animal models and limited data exist on in vitro sex differences relevant to humans. To date, male and female human hepatocytes have not yet been compared in terms of their responses to hepatotoxic drugs. We investigated whether sex-specific differences in acute hepatotoxicity can be observed in vitro by comparing hepatotoxic drug effects in male and female primary human hepatocytes. Significant sex-related differences were found for certain parameters and individual drugs, showing an overall higher sensitivity of female primary hepatocytes to hepatotoxicants. Moreover, our work demonstrated that high content screening is feasible with pooled primary human hepatocytes in suspension. PMID:25849576

Mennecozzi, Milena; Landesmann, Brigitte; Palosaari, Taina; Harris, Georgina; Whelan, Maurice

2015-01-01

270

Sex differences in liver toxicity-do female and male human primary hepatocytes react differently to toxicants in vitro?  

PubMed

There is increasing amount of evidence for sex variation in drug efficiency and toxicity profiles. Women are more susceptible than men to acute liver injury from xenobiotics. In general, this is attributed to sex differences at a physiological level as well as differences in pharmacokinetics and pharmacodynamics, but neither of these can give a sufficient explanation for the diverse responses to xenobiotics. Existing data are mainly based on animal models and limited data exist on in vitro sex differences relevant to humans. To date, male and female human hepatocytes have not yet been compared in terms of their responses to hepatotoxic drugs. We investigated whether sex-specific differences in acute hepatotoxicity can be observed in vitro by comparing hepatotoxic drug effects in male and female primary human hepatocytes. Significant sex-related differences were found for certain parameters and individual drugs, showing an overall higher sensitivity of female primary hepatocytes to hepatotoxicants. Moreover, our work demonstrated that high content screening is feasible with pooled primary human hepatocytes in suspension. PMID:25849576

Mennecozzi, Milena; Landesmann, Brigitte; Palosaari, Taina; Harris, Georgina; Whelan, Maurice

2015-01-01

271

Concurrent sexual partnerships among female sex workers and their non-commercial male partners in Tijuana and Ciudad Juárez, Mexico  

PubMed Central

Objectives To investigate the prevalence and correlates of concurrent (overlapping) sexual partnerships among female sex workers (FSWs) and their non-commercial male partners in two Mexico-U.S. border cities. Methods A cross-sectional survey of FSWs and their non-commercial male partners was conducted in Tijuana and Ciudad Juárez, Mexico (2010–2011). Eligible FSWs and verified non-commercial partners were aged ?18 years; FSWs had ever used hard drugs (lifetime) and recently exchanged sex for money, drugs, or other goods (past month). Participants underwent baseline questionnaires obtaining dates of sex and condom use with ?5 other recurring partners, including FSWs’ regular clients. These dates were compared to dates of sex with enrolled study partners to determine overlap (i.e., “recurring” concurrency). Bivariate probit regression identified recurring concurrency correlates. Results Among 428 individuals (214 couples), past-year recurring concurrency prevalence was 16% and was higher among women than their non-commercial male partners (26% vs. 6%). In 10 couples (5%), both partners reported recurring concurrency. The majority of couples (64%) always had unprotected sex, and most of the individuals (70%) with recurring concurrency “sometimes” or “never” used condoms with their concurrent partners. Recurring concurrency was positively associated with FSWs’ income, men’s caballerismo (a form of traditional masculinity), and men’s belief that their FSW-partners had STIs. Conclusions Recurring concurrency, representing sustained periods of overlapping partnerships in which unprotected sex was common, should be addressed by couple-based STI prevention interventions. PMID:23172036

Robertson, Angela M.; Syvertsen, Jennifer L.; Rangel, M. Gudelia; Staines, Hugo S.; Morris, Martina; Patterson, Thomas L.; Ulibarri, Monica D.; Strathdee, Steffanie A.

2013-01-01

272

Prevalence of Same-Sex Sexual Behavior and Associated Characteristics among Low-Income Urban Males in Peru  

PubMed Central

Background Peru has a concentrated HIV epidemic in which men who have sex with men are particularly vulnerable. We describe the lifetime prevalence of same-sex sexual contact and associated risk behaviors of men in Peru's general population, regardless of their sexual identity. Methods and Results A probability sample of males from low-income households in three Peruvian cities completed an epidemiologic survey addressing their sexual risk behavior, including sex with other men. Serum was tested for HSV-2, HIV, and syphilis. Urine was tested for chlamydia and gonorrhea. A total of 2,271 18–30 year old men and women were contacted, of whom 1,645 (72.4%) agreed to participate in the study. Among the sexually experienced men surveyed, 15.2% (85/558, 95% CI: 12.2%–18.2%) reported a history of sex with other men. Men ever reporting sex with men (MESM) had a lower educational level, had greater numbers of sex partners, and were more likely to engage in risk behaviors including unprotected sex with casual partners, paying for or providing compensated sex, and using illegal drugs. MESM were also more likely to have had previous STI symptoms or a prior STI diagnosis, and had a greater prevalence of HSV-2 seropositivity. Conclusions Many low-income Peruvian men have engaged in same-sex sexual contact and maintain greater behavioral and biological risk factors for HIV/STI transmission than non-MESM. Improved surveillance strategies for HIV and STIs among MESM are necessary to better understand the epidemiology of HIV in Latin America and to prevent its further spread. PMID:17712426

Clark, Jesse L.; Caceres, Carlos F.; Lescano, Andres G.; Konda, Kelika A.; Leon, Segundo R.; Jones, Franca R.; Kegeles, Susan M.; Klausner, Jeffrey D.; Coates, Thomas J.

2007-01-01

273

Prenatal Testosterone Induces Sex-Specific Dysfunction in Endothelium-Dependent Relaxation Pathways in Adult Male and Female Rats1  

PubMed Central

ABSTRACT Prenatal testosterone (T) exposure impacts postnatal cardiovascular function, leading to increases in blood pressure with associated decreased endothelium-dependent vascular relaxation in adult females. Endothelial function in males is not known. Furthermore, which of the endothelial pathways contributes to endothelial dysfunction and if there exists sex differences are not known. The objective of this study was to characterize the relative contribution of nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) to the impaired endothelium-dependent vasodilation in prenatal T-exposed adult males and females. Offspring of pregnant rats treated with T propionate or its vehicle were examined. Telemetric blood pressure levels and endothelium-dependent vascular reactivity were assessed with wire myography. Levels of nitric oxide synthase (NOS3) and Kcnn3 and Kcnn4 channel expression were examined in mesenteric arteries. Mean arterial pressure was significantly higher in T males and females than in controls. Endothelium-dependent acetylcholine relaxation was significantly lower in both T males and females. EDHF-mediated relaxation was specifically blunted in T males (Emax = 48.64% ± 3.73%) compared to that in control males (Emax = 81.71% ± 3.18%); however, NO-mediated relaxation was specifically impaired in T females (Emax = 36.01% ± 4.29%) compared with that in control females (Emax = 54.56% ± 6.37%). Relaxation to sodium nitroprusside and levcromakalim were unaffected with T-treatment. NOS3 protein was decreased in T females but not in T males. Kcnn3 expression was decreased in both T males and females compared to controls. These findings suggest that prenatal T leads to an increase in blood pressure in the adult offspring, associated with blunting of endothelial cell-associated relaxation and that the effects are sex-specific: EDHF-related in males and NO-related in females. PMID:23966325

Chinnathambi, Vijayakumar; Yallampalli, Chandrasekhar; Sathishkumar, Kunju

2013-01-01

274

Opposite sex-linked behaviors and homosexual feelings in the predominantly heterosexual male majority  

Microsoft Academic Search

Whether homosexual feelings are distributed categorically or dimensionally remains controversial. In an earlier series of studies, medical students anonymously reported a dimensional distribution of homosexual feelings, the ratio of homosexual to heterosexual feelings in men correlating with opposite sex-linked behaviors in childhood and adolescence, and, in both sexes, with current degree of opposite sex identity. Prevalence of homosexual feelings was

Nathaniel McConaghy; Neil Buhrich; Derrick Silove

1994-01-01

275

Molecular Identification of XY Sex-Reversed Female and YY Male Channel Catfish  

Technology Transfer Automated Retrieval System (TEKTRAN)

Production of channel catfish leads U.S. aquaculture, and monosex culture may provide higher production efficiencies. Determination of phenotypic sex is labor intensive and not practical for large scale culture. Catfish have an X-Y sex determination system with monomorphic sex chromosomes. Hormonal...

276

The strength of male-driven evolution that is, the magnitude of the sex ratio of mutation rate has been a controversial  

E-print Network

650 The strength of male-driven evolution ­ that is, the magnitude of the sex ratio of mutation mutation rate in males than in females has been well accepted, the magnitude of the male-to-female ratio () of mutation rate remains a point of contention. Knowing the magnitude of is important because it is related

Yi, Soojin

277

Covariance of paternity and sex with laying order explains male bias in extra-pair offspring in a wild bird population  

PubMed Central

It has been hypothesized that parents increase their fitness by biasing the sex ratio of extra-pair offspring (EPO) towards males. Here, we report a male bias among EPO in a wild population of blue tits (Cyanistes caeruleus). This resulted from a decline in both the proportion of males and EPO over the laying order of eggs in the clutch. However, previous studies suggest that, unlike the decline in EPO with laying order, the relationship between offspring sex ratio and laying order is not consistent between years and populations in this species. Hence, we caution against treating the decline in proportion of males with laying order, and the resulting male bias among EPO, as support for the above hypothesis. Variable patterns of offspring sex and paternity over the laying order may explain inconsistent associations between offspring sex and paternity, between and within species. PMID:24026349

Vedder, Oscar; Magrath, Michael J. L.; van der Velde, Marco; Komdeur, Jan

2013-01-01

278

Short-term treatment of adult male zebrafish (Danio Rerio) with 17?-ethinyl estradiol affects the transcription of genes involved in development and male sex differentiation.  

PubMed

The synthetic estrogen 17?-ethinyl estradiol (EE2) disturbs reproduction and causes gonadal malformation in fish. Effects on the transcription of genes involved in gonad development and function that could serve as sensitive biomarkers of reproductive effects in the field is, however, not well known. We have studied mRNA expression in testes and liver of adult zebrafish (Danio rerio) males treated with 0, 5 or 25 ng/L EE2for 14 days. qPCR analysis showed that the mRNA expression of four genes linked to zebrafish male sex determination and differentiation, Anti-Mullerian Hormone, Double sex and mab-related protein, Sry-related HMG box-9a and Nuclear receptor subfamily 5 group number 1b were significantly decreased by 25 ng/L, but not 5 ng/L EE2 compared with the levels in untreated fish. The decreased transcription was correlated with a previously shown spawning failure in these males (Reyhanian et al., 2011. Aquat Toxicol 105, 41-48), suggesting that decreased mRNA expression of genes regulating male sexual function could be involved in the functional sterility. The mRNA level of Cytochrome P-45019a, involved in female reproductive development, was unaffected by hormone treatment. The transcription of the female-specific Vitellogenin was significantly induced in testes. While testicular Androgen Receptor and the Estrogen Receptor-alpha mRNA levels were unchanged, Estrogen receptor-beta was significantly decreased by 25 ng/L EE2. Hepatic Estrogen Receptor-alpha mRNA was significantly increased by both exposure concentrations, while Estrogen Receptor-beta transcription was unaltered. The decreased transcription of male-predominant genes supports a demasculinization of testes by EE2 and might reflect reproductive disturbances in the environment. PMID:24747828

Reyhanian Caspillo, Nasim; Volkova, Kristina; Hallgren, Stefan; Olsson, Per-Erik; Porsch-Hällström, Inger

2014-08-01

279

Sex worker collective organization : Between advocacy group and labour union?  

Microsoft Academic Search

Purpose – The purpose of this paper is to examine contemporary sex worker labour unionism in a number of major western economies because it now faces an acute historical dilemma of being forced into acting as the antithesis of what it professes and aims to be, namely, elite pressure groups. Design\\/methodology\\/approach – Interviews and structured e-mail dialogues with sex worker

Gregor Gall

2010-01-01

280

A protective effect of circumcision among receptive male sex partners of Indian men who have sex with men.  

PubMed

The role of circumcision in the transmission of human immunodeficiency virus (HIV) among men who have sex with men (MSM) in resource restricted regions is poorly understood. This study explored the association of circumcision with HIV seroprevalence, in conjunction with other risk factors such as marriage and sex position, for a population of MSM in India. Participants (n = 387) were recruited from six drop-in centers in a large city in southern India. The overall HIV prevalence in this sample was high, at 18.6%. Bivariate and multivariable analyses revealed a concentration of risk among receptive only, married, and uncircumcised MSM, with HIV prevalence in this group reaching nearly 50%. The adjusted odds of HIV infection amongst circumcised men was less than one fifth that of uncircumcised men [adjusted odds ratio (AOR) 0.17; 95% CI 0.07-0.46; P < 0.001]. Within the group of receptive only MSM, infection was found to be lower among circumcised individuals (AOR, 0.30, 95% CI 0.12-0.76; P < 0.05) in the context of circumcised MSM engaging in more UAI, having a more recent same sex encounter and less lubricant use when compared to uncircumcised receptive men. To further explain these results, future studies should focus on epidemiologic analyses of risk, augmented by social and sexual network analyses of MSM mixing. PMID:21681562

Schneider, John A; Michaels, Stuart; Gandham, Sabitha R; McFadden, Rachel; Liao, Chuanhong; Yeldandi, Vijay V; Oruganti, Ganesh

2012-02-01

281

The effects of low-protein diet and testosterone on sex hormone-binding globulin capacity in male rabbits  

Microsoft Academic Search

The effects of a low-protein high-carbohydrate (LPHC) diet (8% protein 65% to 72% carbohydrate) were compared to those of regular rabbit chow (14% to 16% protein 57% to 64% carbohydrate) on sex hormone-binding globulin (SHBG) capacity in 12 male rabbits. The six rabbits who were fed the LPHC diet for 8 weeks showed a significant increase in their mean SHBG

Christopher Longcope; Sandra Yosha; R. A. Young; Stephen P. Baker; Lewis E. Braverman

1987-01-01

282

The effect of perceived female parasite load on post-copulatory male choice in a sex-role-reversed pipefish  

Microsoft Academic Search

The last several decades of research in behavioral ecology have resulted in a deeper appreciation of post-mating processes\\u000a and sexual conflict in sexual selection. One of the most controversial aspects of sexual selection is cryptic mate choice.\\u000a Here, we take advantage of male pregnancy in a sex-role-reversed pipefish (Syngnathus typhle) to quantify cryptic choice based on perceived parasite load and

Charlyn Partridge; Ingrid Ahnesjö; Charlotta Kvarnemo; Kenyon B. Mobley; Anders Berglund; Adam G. Jones

2009-01-01

283

Serotonin Enhances Central Olfactory Neuron Responses to Female Sex Pheromone in the Male Sphinx Moth Manduca sexta  

Microsoft Academic Search

In the brain of the sphinx moth Manduca sexta, sex-pheromonal information is processed in a prominent male-specific area of the antennal lobe called the macroglomerular complex (MGC). Whole-cell patch-clamp recordings from identified projection (output) neurons in the MGC have shown that serotonin (5-hydroxytryptamine (5-HT)) increases both the excitability of MGC projection neurons and their responses to stimulation with pheromone. At

Peter Kloppenburg; Donald Ferns; Alison R. Mercer

1999-01-01

284

The association between substance use and intimate partner violence within Black male same-sex relationships.  

PubMed

Compared with the extant research on heterosexual intimate partner violence (IPV)-including the knowledge base on alcohol and illicit drug use as predictors of such IPV-there is a paucity of studies on IPV among men who have sex with men (MSM), especially Black MSM. This study investigates the prevalence of experiencing and perpetrating IPV among a sample of Black MSM couples and examines whether heavy drinking and/or illicit substance use is associated with IPV. We conducted a secondary analysis on a data set from 74 individuals (constituting 37 Black MSM couples) screened for inclusion in a couple-based HIV prevention pilot study targeting methamphetamine-involved couples. More than one third (n= 28, 38%) reported IPV at some point with the current partner: 24 both experiencing and perpetrating, 2 experiencing only, and 2 perpetrating only. IPV in the past 30 days was reported by 21 (28%) of the participants: 18 both experiencing and perpetrating, 1 experiencing only, and 2 perpetrating only. Heavy drinking and methamphetamine use each was associated significantly with experiencing and perpetrating IPV throughout the relationship as well as in the past 30 days. Rock/crack cocaine use was significantly associated with any history of experiencing and perpetrating IPV. Altogether, IPV rates in this sample of Black MSM couples equal or exceed those observed among women victimized by male partners as well as the general population of MSM. This exploratory study points to a critical need for further efforts to understand and address IPV among Black MSM. Similar to heterosexual IPV, results point to alcohol and illicit drug use treatment as important avenues to improve the health and social well-being of Black MSM. PMID:24919997

Wu, Elwin; El-Bassel, Nabila; McVinney, L Donald; Hess, Leona; Fopeano, Mark V; Hwang, Hyesung G; Charania, Mahnaz; Mansergh, Gordon

2015-03-01

285

Understanding the diversity of male clients of sex workers in China and the implications for HIV prevention programmes.  

PubMed

Male clients of sex workers have been overlooked in China's HIV prevention efforts. This study aims to examine men's practices and attitudes toward extramarital sexual relationships, motivations for visiting female sex workers (FSWs), perceptions of sexually transmitted infection (STI)/HIV risk and risk prevention strategies used. One hundred and eighty-six clients of FSWs with varying socio-economic statuses were interviewed in different sex work settings. Men described no conflict between their role as a client and a responsible family provider. They described social pressure from peers and business partners to visit FSWs, sexual pleasure and companionship as motivators to seek commercial sex. While some men reported no risks associated with visiting FSWs, others identified risks such as being arrested by the police, robbed by gangs and threatening the health of their families by contracting a STI. This study underscores the diversity of FSW clients and the need to understand the beliefs and behaviours of different client types to develop appropriate HIV prevention programmes. It also demonstrates the feasibility of recruiting different types of male clients, a hard-to-reach population for Chinese HIV prevention efforts. PMID:22313090

Huang, Yingying; Maman, Suzanne; Pan, Suiming

2012-01-01

286

Mating effort and female receptivity: how do male guppies decide when to invest in sex?  

Microsoft Academic Search

Males vary in the degree to which they invest in mating. Several factors can explain this variation, including differences\\u000a in males’ individual condition and the fact that males allocate their energy depending on the context they face in each mating\\u000a attempt. Particularly, female quality affects male reproductive success. Here, we studied whether male guppies (Poecilia reticulata) strategically allocated more mating

Palestina Guevara-Fiore; Jessica Stapley; Penelope J. Watt

2010-01-01

287

Offspring sex ratios reflect lack of repayment by auxiliary males in a cooperatively breeding passerine  

Microsoft Academic Search

The repayment hypothesis posits that primary sex ratios in cooperative species should be biased towards the helping sex because\\u000a these offspring “repay” a portion of their cost through helping behavior and therefore are less expensive to produce. However,\\u000a many cooperatively breeding birds and mammals do not show the predicted bias in the primary sex ratio. Recent theoretical\\u000a work has suggested

Claire W. Varian-Ramos; Jordan Karubian; Vanessa Talbott; Irma Tapia; Michael S. Webster

2010-01-01

288

Epigenetics and Sex-Specific Fitness: An Experimental Test Using Male-Limited Evolution in Drosophila melanogaster  

PubMed Central

When males and females have different fitness optima for the same trait but share loci, intralocus sexual conflict is likely to occur. Epigenetic mechanisms such as genomic imprinting (in which expression is altered according to parent-of-origin) and sex-specific maternal effects have been suggested as ways by which this conflict can be resolved. However these ideas have not yet been empirically tested. We designed an experimental evolution protocol in Drosophila melanogaster that enabled us to look for epigenetic effects on the X-chromosome–a hotspot for sexually antagonistic loci. We used special compound-X females to enforce father-to-son transmission of the X-chromosome for many generations, and compared fitness and gene expression levels between Control males, males with a Control X-chromosome that had undergone one generation of father-son transmission, and males with an X-chromosome that had undergone many generations of father-son transmission. Fitness differences were dramatic, with experimentally-evolved males approximately 20% greater than controls, and with males inheriting a non-evolved X from their father about 20% lower than controls. These data are consistent with both strong intralocus sexual conflict and misimprinting of the X-chromosome under paternal inheritance. However, expression differences suggested that reduced fitness under paternal X inheritance was largely due to deleterious maternal effects. Our data confirm the sexually-antagonistic nature of Drosophila’s X-chromosome and suggest that the response to male-limited X-chromosome evolution entails compensatory evolution for maternal effects, and perhaps modification of other epigenetic effects via coevolution of the sex chromosomes. PMID:23922998

Abbott, Jessica K.; Innocenti, Paolo; Chippindale, Adam K.; Morrow, Edward H.

2013-01-01

289

Faced with inequality: chicken do not have a general dosage compensation of sex-linked genes  

Microsoft Academic Search

BACKGROUND: The contrasting dose of sex chromosomes in males and females potentially introduces a large-scale imbalance in levels of gene expression between sexes, and between sex chromosomes and autosomes. In many organisms, dosage compensation has thus evolved to equalize sex-linked gene expression in males and females. In mammals this is achieved by X chromosome inactivation and in flies and worms

Hans Ellegren; Lina Hultin-Rosenberg; Björn Brunström; Lennart Dencker; Kim Kultima; Birger Scholz

2007-01-01

290

A male-killing Wolbachia carries a feminizing factor and is associated with degradation of the sex-determining system of its host  

PubMed Central

Endosymbiotic bacteria of the genus Wolbachia induce diverse reproductive alterations in their insect hosts. Wolbachia (wSca) infecting the moth Ostrinia scapulalis causes unusual male killing, in which males (genotype: ZZ) selectively die during embryonic and larval development, whereas females (genotype: ZW), in turn, selectively die when cured of infection. To gain insight into the interaction between wSca and the host, we analysed phenotypic and genetic sexes of the embryos and larvae of normal, wSca-infected, and infected-and-cured O. scapulalis by diagnosing the sex-specifically spliced transcripts of Osdsx—a homologue of the sex-determining gene doublesex—and sex chromatin in interphase nuclei, respectively. It was observed that the female-type Osdsx was expressed in the infected male (ZZ) progenies destined to die, whereas the male-type Osdsx was expressed in the cured female (ZW) progenies destined to die. These findings suggest that (i) wSca, a male killer, carries a genetic factor that feminizes the male host, (ii) the sex-determining system of the host is degraded, and (iii) a mismatch between the genetic and phenotypic sexes underlies the sex-specific death. PMID:22219393

Sugimoto, Takafumi N.; Ishikawa, Yukio

2012-01-01

291

A male-killing Wolbachia carries a feminizing factor and is associated with degradation of the sex-determining system of its host.  

PubMed

Endosymbiotic bacteria of the genus Wolbachia induce diverse reproductive alterations in their insect hosts. Wolbachia (wSca) infecting the moth Ostrinia scapulalis causes unusual male killing, in which males (genotype: ZZ) selectively die during embryonic and larval development, whereas females (genotype: ZW), in turn, selectively die when cured of infection. To gain insight into the interaction between wSca and the host, we analysed phenotypic and genetic sexes of the embryos and larvae of normal, wSca-infected, and infected-and-cured O. scapulalis by diagnosing the sex-specifically spliced transcripts of Osdsx-a homologue of the sex-determining gene doublesex-and sex chromatin in interphase nuclei, respectively. It was observed that the female-type Osdsx was expressed in the infected male (ZZ) progenies destined to die, whereas the male-type Osdsx was expressed in the cured female (ZW) progenies destined to die. These findings suggest that (i) wSca, a male killer, carries a genetic factor that feminizes the male host, (ii) the sex-determining system of the host is degraded, and (iii) a mismatch between the genetic and phenotypic sexes underlies the sex-specific death. PMID:22219393

Sugimoto, Takafumi N; Ishikawa, Yukio

2012-06-23

292

Function of the Male Gamete-Specific Fusion Protein, HAP2, in a Seven-Sexed Ciliate  

PubMed Central

Summary HAP2, a male gamete-specific protein conserved across vast evolutionary distances has garnered considerable attention as a potential membrane fusogen required for fertilization in taxa ranging from protozoa and green algae to flowering plants and invertebrate animals [1–6]. However, its presence in Tetrahymena thermophilaa ciliated protozoan with seven sexes or mating types that bypasses the production of male gametes raises interesting questions regarding the evolutionary origins of gamete-specific functions in sexually dimorphic species. Here we show that HAP2 is expressed in all seven mating types of T. thermophila and that fertility is only blocked when the gene is deleted from both cells of a mating pair. HAP2 deletion strains of complementary mating types can recognize one another and form pairs, however pair stability is compromised and membrane pore formation at the nuclear exchange junction is blocked. The absence of pore formation is consistent with previous studies suggesting a role for HAP2 in gamete fusion in other systems. We propose a model in which each of the several hundred membrane pores established at the conjugation junction of mating Tetrahymena represents the equivalent of a male/female interface, and that pore formation is driven on both sides of the junction by the presence of HAP2. Such a model supports the idea that many of the disparate functions of sperm and egg were shared by the “isogametes” of early eukaryotes, and became partitioned to either male or female sex cells later in evolution. PMID:25155508

Cole, Eric S.; Cassidy-Hanley, Donna; Pinello, Jennifer Fricke; Zeng, Hong; Hsueh, Marion; Kolbin, Daniel; Ozzello, Courtney; Giddings, Thomas; Winey, Mark; Clark, Theodore G.

2015-01-01

293

The Sertoli Cell Only Syndrome and Glaucoma in a Sex – Determining Region Y (SRY) Positive XX Infertile Male  

PubMed Central

The XX male syndrome is a rare genetic disorder. The phenotype is variable; it ranges from a severe impairment of the external genitalia to a normal male phenotype with infertility. It generally results from an unequal crossing over between the short arms of the sex chromosomes (X and Y). We are reporting a case of a 38-year-old man who presented with infertility and the features of hypogonadism and glaucoma. The examinations revealed normal external male genitalia, soft small testes, gynaecomastia and glaucoma. The semen analysis showed azoospermia. The serum gonadotropins were high, with low Anti Mullerian Hormone (AMH) and Inhibin B levels. The chromosomal analysis demonstrated a 46, XX karyotype. Fluorescent In-Situ Hybridization (FISH) and Polymerase Chain Reaction (PCR) revealed the presence of a Sex-determining Region Y (SRY). Testicular Fine Needle Aspiration Cytology (FNAC) revealed the Sertoli Cell Only Syndrome (SCOS). The presence of only Sertoli Cells in the testes, with glaucoma in the XX male syndrome, to our knowledge, has not been reported in the literature. PMID:23998093

Jain, Manish; V, Veeramohan; Chaudhary, Isha; Halder, Ashutosh

2013-01-01

294

The Sertoli Cell Only Syndrome and Glaucoma in a Sex - Determining Region Y (SRY) Positive XX Infertile Male.  

PubMed

The XX male syndrome is a rare genetic disorder. The phenotype is variable; it ranges from a severe impairment of the external genitalia to a normal male phenotype with infertility. It generally results from an unequal crossing over between the short arms of the sex chromosomes (X and Y). We are reporting a case of a 38-year-old man who presented with infertility and the features of hypogonadism and glaucoma. The examinations revealed normal external male genitalia, soft small testes, gynaecomastia and glaucoma. The semen analysis showed azoospermia. The serum gonadotropins were high, with low Anti Mullerian Hormone (AMH) and Inhibin B levels. The chromosomal analysis demonstrated a 46, XX karyotype. Fluorescent In-Situ Hybridization (FISH) and Polymerase Chain Reaction (PCR) revealed the presence of a Sex-determining Region Y (SRY). Testicular Fine Needle Aspiration Cytology (FNAC) revealed the Sertoli Cell Only Syndrome (SCOS). The presence of only Sertoli Cells in the testes, with glaucoma in the XX male syndrome, to our knowledge, has not been reported in the literature. PMID:23998093

Jain, Manish; V, Veeramohan; Chaudhary, Isha; Halder, Ashutosh

2013-07-01

295

Function of the male-gamete-specific fusion protein HAP2 in a seven-sexed ciliate.  

PubMed

HAP2, a male-gamete-specific protein conserved across vast evolutionary distances, has garnered considerable attention as a potential membrane fusogen required for fertilization in taxa ranging from protozoa and green algae to flowering plants and invertebrate animals [1-6]. However, its presence in Tetrahymena thermophila, a ciliated protozoan with seven sexes or mating types that bypasses the production of male gametes, raises interesting questions regarding the evolutionary origins of gamete-specific functions in sexually dimorphic species. Here we show that HAP2 is expressed in all seven mating types of T. thermophila and that fertility is only blocked when the gene is deleted from both cells of a mating pair. HAP2 deletion strains of complementary mating types can recognize one another and form pairs; however, pair stability is compromised and membrane pore formation at the nuclear exchange junction is blocked. The absence of pore formation is consistent with previous studies suggesting a role for HAP2 in gamete fusion in other systems. We propose a model in which each of the several hundred membrane pores established at the conjugation junction of mating Tetrahymena represents the equivalent of a male/female interface, and that pore formation is driven on both sides of the junction by the presence of HAP2. Such a model supports the idea that many of the disparate functions of sperm and egg were shared by the "isogametes" of early eukaryotes and became partitioned to either male or female sex cells later in evolution. PMID:25155508

Cole, Eric S; Cassidy-Hanley, Donna; Fricke Pinello, Jennifer; Zeng, Hong; Hsueh, Marion; Kolbin, Daniel; Ozzello, Courtney; Giddings, Thomas; Winey, Mark; Clark, Theodore G

2014-09-22

296

Tricks of the trade: sexual health behaviors, the context of HIV risk, and potential prevention intervention strategies for male sex workers.  

PubMed

Sex work is a significant risk for HIV and sexually transmitted infection (STI) among men who have sex with men (MSM); however, there is a dearth of knowledge about how to reduce risk in this group. MSM sex workers (N = 32) completed a semistructured qualitative interview and a close-ended quantitative assessment. Analyses focused on themes relevant to intervention development. Participants reported an average of 46 male sex partners in the prior 12 months; 31% of participants were HIV-infected. Male sex workers frequently used substances during sex and had elevated levels of psychological distress. Qualitative findings suggest that trauma-informed mental health and substance abuse treatment, ready access to HIV/STI testing and treatment and condoms/informational materials, support groups to address isolation/loneliness, skill-building for risk reduction with sex partners, and paid incentives as add-ons to effective behavior change interventions may be valuable intervention components. Targeting consumers of paid/exchanged sex may assist with changing community norms regarding the practice of transactional sex. Multipronged interventions to decrease sexual risk taking among male sex workers would also benefit from addressing the unique socioeconomic and legal needs of this population. PMID:19928046

Reisner, Sari L; Mimiaga, Matthew J; Mayer, Kenneth H; Tinsley, Jake P; Safren, Steven A

2008-01-01

297

Why do males and females differ? Children's beliefs about sex differences  

Microsoft Academic Search

The present paper focuses on children's beliefs about sex differences and how these are related to age and gender. Seven, ten, and fifteen year olds (N=427) were asked to give explanations for their beliefs about sex differences. In strong agreement with previous research and the cognitive-developmental theoretical framework, marked age differences were found: younger children were more likely than older

Jacqui Smith; Graeme Russell

1984-01-01

298

Male only progeny in Anastrepha suspensa by RNAi-induced sex reversion of chromosomal females  

Technology Transfer Automated Retrieval System (TEKTRAN)

In Tephritidae sex determination is established by orthologs to the Drosophila melanogaster transformer and transformer-2 genes. In contrast, primary signals for sex determination are different in these species corresponding to the number of X chromosomes (XSE) in Drosophilidae species and to the pr...

299

Cross-sex hormone treatment in male-to-female transsexual persons reduces serum brain-derived neurotrophic factor (BDNF).  

PubMed

Serum levels of brain-derived neurotrophic factor (BDNF) are reduced in male-to-female transsexual persons (MtF) compared to male controls. It was hypothesized before that this might reflect either an involvement of BDNF in a biomechanism of transsexualism or to be the result of persistent social stress due to the condition. Here, we demonstrate that 12 month of cross-sex hormone treatment reduces serum BDNF levels in male-to-female transsexual persons independent of anthropometric measures. Participants were acquired through the European Network for the Investigation of Gender Incongruence (ENIGI). Reduced serum BDNF in MtF thus seems to be a result of hormonal treatment rather than a consequence or risk factor of transsexualism. PMID:25498415

Fuss, Johannes; Hellweg, Rainer; Van Caenegem, Eva; Briken, Peer; Stalla, Günter K; T'Sjoen, Guy; Auer, Matthias K

2015-01-01

300

Sex typing and the social perception of gender stereotypic and nonstereotypic behavior: the uniqueness of feminine males.  

PubMed

The social perception of masculine, feminine, androgynous and undifferentiated males was examined. Preadolescent boys (n = 251) were shown a video film portraying a male target playing either a masculine game with boys, a feminine game with girls, a neutral game with boys, or a neutral game with girls and were required to make a variety of inferences about him. All 4 groups made similar cognitive stereotypic inferences that varied in accordance with the gender stereotypic nature of the target's behavior. However, for the affective judgments (e.g., liking the target and wanting to engage in activities with him), the feminine males showed a pattern of inferences that was not only different from other sex role orientations, but often the reverse. The implications of these results for S. L. Bem's gender schema theory (1981) and H. Markus's self schema theory (H. Markus, M. Crane, S. L. Bernstein, & M. Siladi, 1982) are discussed. PMID:8195993

Lobel, T E

1994-02-01

301

Social Deficits in Male Children and Adolescents with Sex Chromosome Aneuploidy: A Comparison of XXY, XYY, and XXYY syndromes  

PubMed Central

We compare social skills in three groups of males with sex chromosome aneuploidies (SCAs) using the Social Responsiveness Scale (SRS). Participants included males with XXY (N=102, M=10.08 years), XYY (N=40, M=9.93 years), and XXYY (N=32, M=11.57 years). XXY had lower (better) SRS scores compared to XYY and XXYY. Scores were not significantly different between XYY and XXYY. In all groups, there were significantly more with SRS scores in the severe range compared to the SRS normative sample. All groups scored lowest (better) on Social Motivation. Relationships between SRS scores and demographic and clinical variables were examined. Results describe the social skills in males with SCA, and suggest that an additional Y chromosome may contribute to increased risk of autistic behaviors. PMID:22502852

Cordeiro, Lisa; Tartaglia, Nicole; Roeltgen, David; Ross, Judith

2012-01-01

302

Transgression and the Situated Body: Gender, Sex, and the Gay Male Teacher.  

ERIC Educational Resources Information Center

This paper begins by examining representations of gay male school teachers in discourses produced by gay men, illustrating the ways gay men represent themselves in public discourse. The literature is reviewed for answers to questions about the role of the gay male teacher in education and the responsibility of the gay male teacher to gay…

Rofes, Eric

303

Male reproductive patterns in nonhibernating bats  

Microsoft Academic Search

Summary. Knowledge relative to the reproduction of nonhibernating bats is reviewed. Events in the male, as they are now understood, are summarized for all families for which data exist. Attention is given to the wide species diversity of male accessory sex organs in respect to gross structure and glandular complement. Stability or variability of organization of the male reproductive system

P. H. Krutzsch

304

The Impact of Single-Sex Education on Male and Female Gains in Mathematics and Reading at the Elementary Level in a Selected School in North Carolina  

ERIC Educational Resources Information Center

The gender gap in achievement and the increasing awareness of differences between male and female cognitive development have ignited a growing interest in single-sex education. No Child Left Behind legislation and amendments to Title IX legislation have increased the number of schools in America offering single-sex education. This 2-year…

O'Neill, Lisa

2011-01-01

305

Male-biased sex ratio among unhatched eggs in great tit Parus major , blue tit P. caeruleus and collared flycatcher Ficedula albicollis  

Microsoft Academic Search

An increasing number of studies have demonstrated that brood sex ratios are frequently unequal, but the proximate mechanisms underlying this deviation are largely unknown. In the current study we analysed deviation from expected 1:1 sex ratio among dead embryos from unhatched eggs collected from partially unhatched clutches of three passerine bird species. We showed that male embryos were significantly overrepresented

Mariusz Cicho?; Joanna Sendecka; Lars Gustafsson

2005-01-01

306

Male and female stem cells and sex reversal in Hydra polyps.  

PubMed

Single interstitial stem cells of male polyps of Hydra magnipapillata give rise to clones that differentiate either male or female gametes. To test the sexual stability of these clones, stem cells were recloned. The results indicate that stem cells from female clones are stable in their sexual differentiation capacity; male stem cells, by comparison, switch sexual phenotype at the rate of 10(-2) per cell per generation. As a result, female polyps contain only female stem cells; male polyps contain a mixture of male and female stem cells. A model is presented in which the sexual phenotype of Hydra polyps is controlled by (i) the switching rate of male and female stem cells and (ii) the repression of female differentiation by male stem cells. PMID:16593789

Bosch, T C; David, C N

1986-12-01

307

On same-sex sexual behaviors among male bachelors in rural China: evidence from a female shortage context.  

PubMed

Using data from a survey conducted in the rural areas of Anhui Province, this study adopted the crosstabs and logistic regression model to analyze the same-sex sexual behaviors of forced male bachelors and the determinants when compared with married men with same ages. The prevalence of same-sex sexual behaviors among the unmarried men was reported as 17.2%, significantly higher than 8.9% among married men with same ages, indicating that same-sex sexual behaviors could be as a compensation for the absence of female sexual partners to some extent for those marriage squeezed or forced male bachelors. Among all groups, the occurrence of unprotected sexual behaviors were reported above 60%, regardless of marital status and the genders of sexual partners; the scores obtained on knowledge of acquired immune deficiency syndrome (AIDS) and sexually transmitted diseases (STDs) among bachelors (AIDS knowledge = 2.85; STDs knowledge = 2.38) are much poorer than those of married men (AIDS knowledge = 3.45; STDs knowledge = 2.79), which might exert potential negative impacts on men's health. PMID:21816858

Yang, Xueyan; Attané, Isabelle; Li, Shuzhuo; Zhang, Qunlin

2012-03-01

308

Organization of Territorial Marking Behavior by Testosterone During Puberty in Male Tree Shrews  

Microsoft Academic Search

According to current hypotheses, in mammals male-specific behavior is organized perinatally, and activated in adulthood by male gonadal hormones. However, this strict differentiation between early organizational and late activational hormone effects has been criticized recently. Around puberty the testosterone levels of male mammals rise far above adult levels. In this study we examined the relevance of this pubertal testosterone peak

Florian Eichmann; Dietrich V Holst

1998-01-01

309

Context matters: The moderating role of bar context in the association between substance use during sex and condom use among male clients of female sex workers in Tijuana, Mexico  

PubMed Central

Tijuana is situated on Mexico’s northern border with the U.S., where sex work is quasi-legal. Whereas previous work has focused on the risk behaviors of female sex workers (FSWs), less is known about the risk behaviors of their male clients. Further, research has not examined structural factors as moderators of the association between substance use and condom use, including the contexts in which sex takes place. The purpose of the current study is to examine whether having sex with FSWs in a bar moderates the link between alcohol intoxication during sex and condom use. We recruited 375 male clients of FSWs in Tijuana, Mexico from San Diego, California and Tijuana. Using computer assisted interviewing, we surveyed participants on their alcohol use, condom use, and physical contexts of sex with FSWs in the past four months. Results showed that more frequent intoxication during sex with FSWs is associated with more unprotected sex, but only among clients having sex with FSWs in a bar context. Results point to potential reasons for inconsistent condom use with FSWs in this context, including lower risk perceptions of sex with FSWs in bars. Future research should examine structural factors that underlie clients’ risk behavior in bars in order to inform structural-level HIV prevention interventions. PMID:23640653

Pitpitan, Eileen V.; Wagner, Karla D.; Goodman, David; Semple, Shirley J.; Chavarin, Claudia; Strathdee, Steffanie A.; Patterson, Thomas L.

2013-01-01

310

Evolution of sex determination systems with heterogametic males and females in silene.  

PubMed

The plant genus Silene has become a model for evolutionary studies of sex chromosomes and sex-determining mechanisms. A recent study performed in Silene colpophylla showed that dioecy and the sex chromosomes in this species evolved independently from those in Silene latifolia, the most widely studied dioecious Silene species. The results of this study show that the sex-determining system in Silene otites, a species related to S. colpophylla, is based on female heterogamety, a sex determination system that is unique among the Silene species studied to date. Our phylogenetic data support the placing of S. otites and S. colpophylla in the subsection Otites and the analysis of ancestral states suggests that the most recent common ancestor of S. otites and S. colpophylla was most probably dioecious. These observations imply that a switch from XX/XY sex determination to a ZZ/ZW system (or vice versa) occurred in the subsection Otites. This is the first report of two different types of heterogamety within one plant genus of this mostly nondioecious plant family. PMID:24299418

Slancarova, Veronika; Zdanska, Jana; Janousek, Bohuslav; Talianova, Martina; Zschach, Christian; Zluvova, Jitka; Siroky, Jiri; Kovacova, Viera; Blavet, Hana; Danihelka, Jiri; Oxelman, Bengt; Widmer, Alex; Vyskot, Boris

2013-12-01

311

Sexually Transmitted Infections among Heterosexual Male Clients of Female Sex Workers in China: A Systematic Review and Meta-Analysis  

PubMed Central

Background Female sex workers have been the target of numerous sexually transmitted infection (STI) prevention strategies in China, but their male clients have attracted considerably less public health attention and resources. We sought to systematically assess the prevalence of HIV, syphilis, gonorrhea, and chlamydia among heterosexual male clients of female sex workers in China. Methods/Principal Findings Original research manuscripts were identified by searching Chinese and English language databases, and 37 studies analyzing 26,552 male clients were included in the review. Client STI prevalence across studies was heterogeneous. Pooled prevalence estimates and 95% confidence intervals were 0.68% (0.36–1.28%) for HIV, 2.91% (2.17–3.89%) for syphilis, 2.16% (1.46–3.17%) for gonorrhea, and 8.01% (4.94–12.72%) for chlamydia. Conclusions/Significance The pooled prevalence estimates of HIV, syphilis, gonorrhea, and chlamydia among clients in this review exceed the prevalences previously reported among population-representative samples and low-risk groups in China. However, heterogeneity across studies and sampling limitations prevent definitive conclusions about how the prevalence of STIs in this population compares to the general population. These findings suggest a need for greater attention to clients’ sexual risk and disease prevalence in China’s STI research agenda in order to inform effective prevention policies. PMID:23951153

McLaughlin, Megan M.; Chow, Eric P. F.; Wang, Cheng; Yang, Li-Gang; Yang, Bin; Huang, Jennifer Z.; Wang, Yanjie; Zhang, Lei; Tucker, Joseph D.

2013-01-01

312

Diagnosis of prolactinoma in two male-to-female transsexual subjects following high-dose cross-sex hormone therapy.  

PubMed

Male-to-female transsexual persons use oestrogens + antiandrogens to adapt their physical bodies to the female sex. Doses are usually somewhat higher than those used by hypogonadal women receiving oestrogen replacement. Particularly in cases of self-adminstration of cross-sex hormones, doses may be very high. Oestrogens are powerful stimulators of synthesis and release of prolactin and serum prolactin levels are usually somewhat increased following oestrogen treatment. Prolactinomas have been reported in male-to-female transsexual persons, both after use of high and conventional doses of oestrogens but remain rare events. We report two new cases of prolactinomas in male-to-female transsexual persons, one in a 41-year-old subject who had used nonsupervised high-dose oestrogen treatment since the age of 23 years and another one in a 42 year old who had initiated oestrogen treatment at the age of 17 years. Their serum prolactin levels were strongly increased, and the diagnosis of a pituitary tumour was confirmed by imaging techniques. Both cases responded well to treatment with cabergoline treatment whereupon serum prolactin normalised. Our two cases are added to the three cases of prolactinomas in the literature in persons who had used supraphysiological doses of oestrogens. PMID:25059808

Cunha, F S; Domenice, S; Câmara, V L; Sircili, M H P; Gooren, L J G; Mendonça, B B; Costa, E M F

2014-07-25

313

No evidence for increased extinction proneness with decreasing effective population size in a parasitoid with complementary sex determination and fertile diploid males  

PubMed Central

Background In species with single locus complementary sex determination (sl-CSD), the sex of individuals depends on their genotype at one single locus with multiple alleles. Haploid individuals are always males. Diploid individuals are females when heterozygous, but males when homozygous at the sex-determining locus. Diploid males are typically unviable or effectively sterile, hence imposing a genetic load on populations. Diploid males are produced from matings of partners that share an allele at the sex-determining locus. The lower the allelic diversity at the sex-determining locus, the more diploid males are produced, ultimately impairing the growth of populations and jeopardizing their persistence. The gregarious endoparasitoid wasp Cotesia glomerata is one of only two known species with sl-CSD and fertile diploid males. Results By manipulating the relatedness of the founders, we established replicated experimental populations of the parasitoid C. glomerata differing in their genetic effective size, and thus in allelic richness at the sex-determining locus and in the expected magnitude of diploid male production. Our long-term survey of population welfare and persistence did not provide evidence for increased proneness to population extinction with decreasing initial genetic effective population size. Most recorded surrogates of fitness nevertheless decayed over time and most experimental populations eventually went extinct, suggesting that the negative effects of inbreeding outweighed any premium from the fertility of diploid males. Conclusions The fertility of diploid males may have evolved as an adaptation prompted by the risk of extinction looming over small isolated populations of species with sl-CSD. However, fertility of diploid males does not negate the costs imposed by their production, and although it may temporarily stave off extinction, it is not sufficient to eradicate the negative effects of inbreeding. PMID:21110868

2010-01-01

314

Development of systemic lupus erythematosus in a male-to-female transsexual: the role of sex hormones revisited.  

PubMed

Systemic lupus erythematosus (SLE) predominantly affects women of childbearing age. The infrequency of SLE in men and disease onset in prepubertal or postmenopausal women suggests a role of estrogen in the predisposition to the disease. Patients with hypergonadotrophic hypogonadism are prone to the development of SLE, and the use of exogenous estrogens in women increases the relative risk of SLE onset and disease flares. These observations provide indirect evidence for an opposite role of estrogens and androgens in the pathogenesis of SLE. We report on a male-to-female transsexual who developed SLE 20 years after sex-reassignment surgery and prolonged estrogen therapy. The role of sex hormones in SLE is revisited. PMID:23897544

Chan, K L; Mok, C C

2013-11-01

315

Male-Killing Spiroplasma Induces Sex-Specific Cell Death via Host Apoptotic Pathway  

PubMed Central

Some symbiotic bacteria cause remarkable reproductive phenotypes like cytoplasmic incompatibility and male-killing in their host insects. Molecular and cellular mechanisms underlying these symbiont-induced reproductive pathologies are of great interest but poorly understood. In this study, Drosophila melanogaster and its native Spiroplasma symbiont strain MSRO were investigated as to how the host's molecular, cellular and morphogenetic pathways are involved in the symbiont-induced male-killing during embryogenesis. TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) staining, anti-cleaved-Caspase-3 antibody staining, and apoptosis-deficient mutant analysis unequivocally demonstrated that the host's apoptotic pathway is involved in Spiroplasma-induced male-specific embryonic cell death. Double-staining with TUNEL and an antibody recognizing epidermal marker showed that embryonic epithelium is the main target of Spiroplasma-induced male-specific apoptosis. Immunostaining with antibodies against markers of differentiated and precursor neural cells visualized severe neural defects specifically in Spiroplasma-infected male embryos as reported in previous studies. However, few TUNEL signals were detected in the degenerate nervous tissues of male embryos, and the Spiroplasma-induced neural defects in male embryos were not suppressed in an apoptosis-deficient host mutant. These results suggest the possibility that the apoptosis-dependent epidermal cell death and the apoptosis-independent neural malformation may represent different mechanisms underlying the Spiroplasma-induced male-killing. Despite the male-specific progressive embryonic abnormality, Spiroplasma titers remained almost constant throughout the observed stages of embryonic development and across male and female embryos. Strikingly, a few Spiroplasma-infected embryos exhibited gynandromorphism, wherein apoptotic cell death was restricted to male cells. These observations suggest that neither quantity nor proliferation of Spiroplasma cells but some Spiroplasma-derived factor(s) may be responsible for the expression of the male-killing phenotype. PMID:24550732

Harumoto, Toshiyuki; Anbutsu, Hisashi; Fukatsu, Takema

2014-01-01

316

Synchronous firing of antennal-lobe projection neurons encodes the behaviorally effective ratio of sex-pheromone components in male Manduca sexta  

PubMed Central

Olfactory stimuli that are essential to an animal's survival and reproduction are often complex mixtures of volatile organic compounds in characteristic proportions. Here, we investigated how these proportions are encoded in the primary olfactory processing center, the antennal lobe (AL), of male Manduca sexta moths. Two key components of the female's sex pheromone, present in an approximately 2:1 ratio, are processed in each of two neighboring glomeruli in the macroglomerular complex (MGC) of males of this species. In wind-tunnel flight experiments, males exhibited behavioral selectivity for ratios approximating the ratio released by conspecific females. The ratio between components was poorly represented, however, in the firing-rate output of uniglomerular MGC projection neurons (PNs). PN firing rate was mostly insensitive to the ratio between components, and individual PNs did not exhibit a preference for a particular ratio. Recording simultaneously from pairs of PNs in the same glomerulus, we found that the natural ratio between components elicited the most synchronous spikes, and altering the proportion of either component decreased the proportion of synchronous spikes. The degree of synchronous firing between PNs in the same glomerulus thus selectively encodes the natural ratio that most effectively evokes the natural behavioral response to pheromone. PMID:24002682

Martin, Joshua P.; Lei, Hong; Riffell, Jeffrey A.; Hildebrand, John G.

2013-01-01

317

Evaluation of organ doses and effective dose according to the ICRP Publication 110 reference male/female phantom and the modified ImPACT CT patient dosimetry.  

PubMed

We modified the Imaging Performance Assessment of CT scanners (ImPACT) to evaluate the organ doses and the effective dose based on the International Commission on Radiological Protection (ICRP) Publication 110 reference male/female phantom with the Aquilion ONE ViSION Edition scanner. To select the new CT scanner, the measurement results of the CTDI100,c and CTDI100,p for the 160 (head) and the 320 (body) mm polymethylmethacrylate phantoms, respectively, were entered on the Excel worksheet. To compute the organ doses and effective dose of the ICRP reference male/female phantom, the conversion factors obtained by comparison between the organ doses of different types of phantom were applied. The organ doses and the effective dose were almost identical for the ICRP reference male/female and modified ImPACT. The results of this study showed that, with the dose assessment of the ImPACT, the difference in sex influences only testes and ovaries. Because the MIRD-5 phantom represents a partially hermaphrodite adult, the phantom has the dimensions of the male reference man including testes, ovaries, and uterus but no female breasts, whereas the ICRP male/female phantom includes whole-body male and female anatomies based on high-resolution anatomical datasets. The conversion factors can be used to estimate the doses of a male and a female accurately, and efficient dose assessment can be performed with the modified ImPACT. PMID:25207566

Kobayashi, Masanao; Asada, Yasuki; Matsubara, Kosuke; Matsunaga, Yuta; Kawaguchi, Ai; Katada, Kazuhiro; Toyama, Hiroshi; Koshida, Kichiro; Suzuki, Shouichi

2014-01-01

318

Carotenoid-Based Ornaments of Female and Male American Goldfinches (Spinus tristis) Show Sex-Specific Correlations with Immune Function and Metabolic Rate  

Microsoft Academic Search

Conspicuous ornamentation has been linked to immunological and physiological condition in males of many species. In species where both sexes are ornamented, it is unclear whether the signal content of ornaments differs between males and females. We examined the immunological and physiological correlates of carotenoid-based bill and plumage ornamentation in American goldfinches Spinus tristis, a species in which bright orange

Ryan J. Kelly; Troy G. Murphy; Keith A. Tarvin; Gary Burness

2012-01-01

319

Female aggression and male peace-keeping in a cichlid fish harem: conflict between and within the sexes in Lamprologus ocellatus  

Microsoft Academic Search

Conflicts of interest within and between the sexes are important processes leading to variability in mating systems. The behavioral interactions mediating conflict are little documented. We studied pairs and harems of the snail-shell inhabiting cichlid fish Lamprologus ocellatus in the laboratory. Due to their larger size, males controlled the resource that limited breeding: snail shells. Males were able to choose

Bernhard Walter; Fritz Trillmich

1994-01-01

320

Localization of Male-Specifically Expressed MROS Genes of Silene latifolia by PCR on Flow-Sorted Sex Chromosomes and Autosomes  

Microsoft Academic Search

The dioecious white campion Silene latifolia (syn. Melandrium album) has heteromorphic sex chromo- somes, XX in females and XY in males, that are larger than the autosomes and enable their separation by flow sorting. The group of MROS genes, the first male-specifically expressed genes in dioecious plants, was recently identified in S. latifolia. To localize the MROS genes, we used

Eduard Kejnovsky ´; Jan Vrana; Sachihiro Matsunaga; Premysl Soucek; Jaroslav Dolezel; Boris Vyskot

321

Expression patterns of sex-determination genes in single male and female embryos of two Bactrocera fruit fly species during early development.  

PubMed

In tephritids, the sex-determination pathway follows the sex-specific splicing of transformer (tra) mRNA, and the cooperation of tra and transformer-2 (tra-2) to effect the sex-specific splicing of doublesex (dsx), the genetic double-switch responsible for male or female somatic development. The Dominant Male Determiner (M) is the primary signal that controls this pathway. M, as yet uncharacterized, is Y-chromosome linked, expressed in the zygote and directly or indirectly diminishes active TRA protein in male embryos. Here we first demonstrated the high conservation of tra, tra-2 and dsx in two Australian tephritids, Bactrocera tryoni and Bactrocera jarvisi. We then used quantitative reverse transcription PCR on single, sexed embryos to examine expression of the key sex-determination genes during early embryogenesis. Individual embryos were sexed using molecular markers located on the B.?jarvisi?Y-chromosome that was also introgressed into a B.?tryoni line. In B.?jarvisi, sex-specific expression of tra transcripts occurred between 3 to 6?h after egg laying, and the dsx isoform was established by 7?h. These milestones were delayed in B.?tryoni lines. The results provide a time frame for transcriptomic analyses to identify M and its direct targets, plus information on genes that may be targeted for the development of male-only lines for pest management. PMID:25116961

Morrow, J L; Riegler, M; Frommer, M; Shearman, D C A

2014-12-01

322

Familiarity and Sex Based Stereotypes on Instant Impressions of Male and Female Faculty  

ERIC Educational Resources Information Center

To address the stranger-to-stranger critique of stereotyping research, psychology students (n = 139) and law students (n = 58) rated photographs of familiar or unfamiliar male or female professors on competence. Results from Study 1 indicated that familiar male psychology faculty were rated as more competent than were familiar female faculty,…

Nadler, Joel T.; Berry, Seth A.; Stockdale, Margaret S.

2013-01-01

323

Sex Differences in the Perception of Male/Female Unethical Behavior.  

ERIC Educational Resources Information Center

Some research has shown that women's achievements in traditionally masculine fields are devalued. To determine if females would be judged more harshly than males for performing unethical behaviors in order to gain entry in competitive professions, and to examine gender differences in the evaluation of unethical conduct, college students (52 males

Lewis, Katharine H.; Hartnett, John J.

324

BROOD SEX RATIOS ARE RELATED TO MALE SIZE BUT NOT TO ATTRACTIVENESS IN COMMON YELLOWTHROATS  

E-print Network

(GEOTHLYPIS TRICHAS) B A , J C. G , M C. P , L A. W ,1 P O. D Department of Biological Sciences, P.O. Box 413. In the Common Yellowthroat (Geothlypis trichas), males with larger black facial masks are more likely to gain, Geothlypis trichas, male ornaments, paternity, sexual selection. El Cociente de Sexos en las Nidadas Está

Dunn, Peter O.

325

Costly interactions between the sexes: combined effects of male sexual harassment and female choice?  

Microsoft Academic Search

Male and female interests can differ profoundly regarding quality and quantity of mates. Especially in promiscuous mating systems, males often inflict costs on females that may precipitate in negative fitness consequences. In reality, however, discerning between female costs arising from a sexual conflict and costs arising from female mate choice is not trivial. In livebearing fishes, for example, costs of

Michael Tobler; Ingo Schlupp; Martin Plath

2011-01-01

326

Birth Order and Sibling Sex Ratio in Homosexual Male Adolescents and Probably Prehomosexual Feminine Boys  

Microsoft Academic Search

The purpose of this study was to extend the findings, previously limited to adults, that male homosexuals have a greater than average proportion of male siblings and a later than average birth order. There were 2 matched groups of 156 probands. The homosexual–prehomosexual (HP) group included boys referred to a specialty clinic because of persistent cross-gender behavior plus homosexual adolescents

Ray Blanchard; Kenneth J. Zucker; Susan J. Bradley; Caitlin S. Hume

1995-01-01

327

The Association between the Levels of Serum Ferritin and Sex Hormones in a Large Scale of Chinese Male Population  

PubMed Central

Background The ferritin is an important participant of iron-storage but its regulation and related factors were not well defined. The present objective was to explore the potential association between serum ferritin levels and sex hormones. Methods 1999 Chinese men in the Fangchenggang Area Male Health and Examination Survey (FAMHES) were recruited in this cross-sectional study. Levels of serum ferritin, total testosterone (free testosterone was calculated from the total one), estradiol and sex hormone-binding protein were detected in venous blood samples. The effects of age, BMI, smoking as well as alcohol consumption were analyzed on ferritin levels, respectively, and then the Pearson’s correlation analysis was used to evaluate the association between ferritin levels and sex hormones adjusting for the above factors. Results The age, BMI and alcohol consumption significantly affected serum ferritin levels, but there was no significant difference between smokers and nonsmokers. Ferritin levels were significantly and negatively associated with total testosterone (R?=??0.205, P< 0.001), sex hormone-binding protein (R?=??0.161, P<0.001) and free testosterone (R?=??0.097, P<0.001). After age and alcohol consumption were adjusted, the above associations were still significant (R?=??0.200, ?0.181 and ?0.083, respectively, all P<0.001). However, there was only borderline negative association between ferritin levels and estradiol (adjusted R?=??0.039, P?=?0.083). Conclusion The large scale of epidemic results showed the significantly negative associations between serum ferritin levels and sex hormones, which may provide more clues to explore the potential regulation and biological mechanism of ferritin. PMID:24146788

Zhang, Haiying; Gao, Yong; Tan, Aihua; Zhang, Shijun; Xiao, Qiang; Zhang, Bing; Huang, Lulu; Ye, Bingbing; Qin, Xue; Wu, Chunlei; Lu, Zheng; Zhang, Youjie; Liao, Ming; Yang, Xiaobo; Mo, Zengnan

2013-01-01

328

DNA is organized into 46 chromosomes including sex chromosomes, 3D animation with no audioSite: DNA Interactive (www.dnai.org)  

NSDL National Science Digital Library

The millions of bases, which make up the human genome are organized into structures called chromosomes. These are arranged into 22 matching pairs plus 1 pair of sex chromosomes consisting of 2 X's in women and an X and a Y in men. So humans have a total of 46 chromosomes in each cell, known collectively as a karyotype. This set of chromosomes has a Y, so it must belong to a male.

2008-10-06

329

Mechanisms of INSL3 signaling in male reproductive organs.  

PubMed

Global ablation of INSL3 hormone or its receptor RXFP2 in male mice results in cryptorchidism and infertility. Using novel LacZ knock-in Rxfp2 allele we demonstrated a strong expression of this gene in postmeiotic germ cells. RXFP2 was expressed in embryonic and neonatal gubernaculum. No RXFP2 expression was detected in cremaster muscles in adult mice. We produced a floxed allele of Rxfp2 and then deleted this gene in male germ cells in testes located in normal scrotal position. No differences in fertility or spermatogenesis of such males were found, suggesting non-essential role of INSL3 signaling in germ cell differentiation in adult males. We have also produced shRNA transgenic mice with reduced RXFP2 expression Such males manifested various degree of uni- and bilateral cryptorchidism. Total gene expression analysis of the mutant cremasteric sacs indicated misexpression of a significant number of genes in Wnt/beta-catenin and NOTCH pathways. Conditional deletion of beta-catenin or Notch1 genes in male gubernacular ligament resulted in its abnormal development. Our data suggest that beta-catenin and NOTCH1 pathways are potential targets of INSL3 signaling during gubernacular development. PMID:24640567

Huang, Zaohua; Kaftanovskaya, Elena M; Rivas, Bryan; Agoulnik, Alexander I

2013-01-01

330

Sex-specific survival rates of adult roseate terns: are males paying a higher reproductive cost than females?  

USGS Publications Warehouse

A long-term mark-recapture/resighting program has been carried out on the Roseate Terns (Sterna dougallii) nesting at Falkner Island, Connecticut, USA from the late 1980s through the mid 2000s, and from 1995-1998 an intensive collaborative study of food-provisioning of chicks by their parents also was conducted on many of the banded individuals at this site. Adult female Roseate Terns have significantly higher 'local survival' rates than do males. While both sexes feed their young, males usually have higher prey delivery rates than do females and do most feeding of the (oldest if more than one) chick just before it fledges. Males usually depart at the same time as the (oldest) fledgling, while successful females parents may linger at the colony site for up to two weeks. The lower 'local survival' rate of males probably does not represent lower colony-site fidelity, but instead may reflect the price they pay for doing more 'child care,' especially if fledglings are still dependant on them for food during post breeding dispersal and (at least early) migration.

Spendelow, J.A.; Shealer, D.A.; Hatfield, J.S.; Nichols, J.D.; Nisbet, I.C.T.

2005-01-01

331

Boredom Proneness, Social Connectedness, and Sexual Addiction among Men Who Have Sex with Male Internet Users  

ERIC Educational Resources Information Center

The authors collected surveys from 517 men who have sex with men (MSM) recruited from Internet chat rooms to examine the relationships among boredom, social connectedness, and sexual addiction. The results provide addictions professionals psychosocial factors to assess when working with sexually addicted MSM. (Contains 3 tables.)

Chaney, Michael P.; Blalock, Andrew C.

2006-01-01

332

A Trivers-Willard Effect in Contemporary Humans: Male-Biased Sex Ratios among Billionaires  

Microsoft Academic Search

BackgroundNatural selection should favour the ability of mothers to adjust the sex ratio of offspring in relation to the offspring's potential reproductive success. In polygynous species, mothers in good condition would be advantaged by giving birth to more sons. While studies on mammals in general provide support for the hypothesis, studies on humans provide particularly inconsistent results, possibly because the

Elissa Z. Cameron; Fredrik Dalerum; David Reby

2009-01-01

333

A Trivers-Willard Effect in Contemporary Humans: Male-Biased Sex Ratios among Billionaires  

Microsoft Academic Search

Background: Natural selection should favour the ability of mothers to adjust the sex ratio of offspring in relation to the offspring's potential reproductive success. In polygynous species, mothers in good condition would be advantaged by giving birth to more sons. While studies on mammals in general provide support for the hypothesis, studies on humans provide particularly inconsistent results, possibly because

Elissa Z. Cameron; Fredrik Dalerum

2009-01-01

334

Assessment of Deviant Arousal in Adult Male Sex Offenders with Developmental Disabilities  

ERIC Educational Resources Information Center

Ten individuals, residing in a treatment facility specializing in the rehabilitation of sex offenders with developmental disabilities, participated in an arousal assessment involving the use of the penile plethysmograph. The arousal assessments involved measuring change in penile circumference to various categories of stimuli both appropriate…

Reyes, Jorge R.; Vollmer, Timothy R.; Sloman, Kimberly N.; Hall, Astrid; Reed, Robert; Jansen, Greg; Carr, Sam; Jackson, Kevin; Stoutimore, Michael

2006-01-01

335

Administration of estradiol benzoate before insemination could skew secondary sex ratio toward males in Holstein dairy cows.  

PubMed

The present study was conducted to investigate the effect of estradiol benzoate administration before insemination on secondary sex ratio (proportion of male calves at birth) in Holstein dairy cows. Cows (n = 1,647) were randomly assigned to 2 experimental groups by parity over a 1-yr period. Cows in the control group (n = 827; 232 primiparous and 595 multiparous cows) received 2 administrations of PGF2? (500 ?g) 14 d apart, started at 30 to 35 d postpartum. Twelve d after the second PGF2? injection, cows received GnRH (100 ?g), followed by administration of PGF2? 7 d later. Cows in the treatment group (n = 820; 238 primiparous and 582 multiparous cows) received the same hormonal administrations as the cows in the control group. Additionally, cows in the treatment group received estradiol benzoate (1 mg) 1 d after the third PGF2? injection. Estrus detection by visual observation was started 1 d after the third PGF2? injection and after estradiol administration in the control (for 6 d) and treatment (for 36 h) groups, respectively. Artificial insemination was carried out 12 h after observation of standing estrus. Exposure of cows to heat stress at conception was determined based on temperature-humidity index. Estrus detection rate was lower in primiparous than in multiparous cows (P < 0.05), but conception rate was higher in primiparous vs multiparous cows (P < 0.05). Estradiol administration improved estrus detection rate and fertility (P < 0.05); moreover, it increased secondary sex ratio (adjusted odds ratio: 1.645; P = 0.017). Exposure to heat stress diminished heat detection rate and fertility (P < 0.05), and altered secondary sex ratio toward males (adjusted odds ratio: 2.863; P = 0.012). In conclusion, the present study revealed that estradiol administration before insemination could improve fertility and increase the probability of calves being male in Holstein dairy cows. Moreover, the results showed that cows exposed to heat stress around conception had diminished fertility and increased secondary sex ratio. PMID:24906936

Emadi, S R; Rezaei, A; Bolourchi, M; Hovareshti, P; Akbarinejad, V

2014-07-01

336

Sex, Lies, and Video Games: The Portrayal of Male and Female Characters on Video Game Covers  

Microsoft Academic Search

Two hundred twenty-five console video game covers obtained from online retail sites were examined for portrayals of men and\\u000a women. We hypothesized that males would be portrayed more often, but that females would be portrayed in a more hyper-sexualized\\u000a manner. Male characters were almost four times more frequently portrayed than female characters and were given significantly\\u000a more game relevant action.

Melinda C. R. Burgess; Steven Paul Stermer; Stephen R. Burgess

2007-01-01

337

Sex, Drugs, Violence, and HIV Status Among Male-to-Female Transgender Persons in Houston, Texas  

Microsoft Academic Search

To inform the Community Planning Group (Houston, Texas) in setting HIV-prevention priorities, risk behavior surveys were completed by 67 male-to-female (MtF) transgender persons. By self-identification, 58% were preoperative and 48% were self-described heterosexual women. We found this small sample of male-to-female transgender individuals to have high rates of HIV infection, and high prevalence of risky behaviors, intimate partner violence, and

Jan M. H. Risser; Andrea Shelton; Sheryl McCurdy; John Atkinson; Paige Padgett; Bernardo Useche; Brenda Thomas; Mark Williams

2005-01-01

338

Is the rate of insertion and deletion mutation male biased?: Molecular evolutionary analysis of avian and primate sex chromosome sequences.  

PubMed Central

The rate of mutation for nucleotide substitution is generally higher among males than among females, likely owing to the larger number of DNA replications in spermatogenesis than in oogenesis. For insertion and deletion (indel) mutations, data from a few human genetic disease loci indicate that the two sexes may mutate at similar rates, possibly because such mutations arise in connection with meiotic crossing over. To address origin- and sex-specific rates of indel mutation we have conducted the first large-scale molecular evolutionary analysis of indels in noncoding DNA sequences from sex chromosomes. The rates are similar on the X and Y chromosomes of primates but about twice as high on the avian Z chromosome as on the W chromosome. The fact that indels are not uncommon on the nonrecombining Y and W chromosomes excludes meiotic crossing over as the main cause of indel mutation. On the other hand, the similar rates on X and Y indicate that the number of DNA replications (higher for Y than for X) is also not the main factor. Our observations are therefore consistent with a role of both DNA replication and recombination in the generation of short insertion and deletion mutations. A significant excess of deletion compared to insertion events is observed on the avian W chromosome, consistent with gradual DNA loss on a nonrecombining chromosome. PMID:12750337

Sundström, Hannah; Webster, Matthew T; Ellegren, Hans

2003-01-01

339

Females prefer to associate with males with longer intromittent organs in mosquitofish  

PubMed Central

Sexual selection is a major force behind the rapid evolution of male genital morphology among species. Most within-species studies have focused on sexual selection on male genital traits owing to events during or after copulation that increase a male's share of paternity. Very little attention has been given to whether genitalia are visual signals that cause males to vary in their attractiveness to females and are therefore under pre-copulatory sexual selection. Here we show that, on average, female eastern mosquitofish Gambusia holbrooki spent more time in association with males who received only a slight reduction in the length of the intromittent organ (‘gonopodium’) than males that received a greater reduction. This preference was, however, only expressed when females chose between two large males; for small males, there was no effect of genital size on female association time. PMID:19755529

Kahn, Andrew T.; Mautz, Brian; Jennions, Michael D.

2010-01-01

340

mgm 1, the earliest sex-specific germline marker in Drosophila, reflects expression of the gene esg in male stem cells.  

PubMed

The pathway that controls sex in Drosophila has been well characterized. The elements of this genetic hierarchy act cell-autonomously in somatic cells. We have previously shown that the sex of germ cells is determined by a different mechanism and that somatic and autonomously acting elements interact to control the choice between spermatogenesis and oogenesis. A target for both types of signals is the enhancer-trap mgm1, which monitors male-specific gene expression in germ cells. Here we report that mgm1 reflects the expression of escargot (esg), a member of the snail gene family, which are transcription factors with zink finger motifs. Genes of this family partially redundantly control a number of processes involving cell fate choices. The regulation of gene expression in germ cells by sex-specific esg enhancers is already seen in embryos. Therefore, autonomous and non-autonomous sex-specific factors that participate in germline sex determination are already present at this early stage. esg is expressed in the male gonad, both in somatic cells and in germline stem cells. We show that esg expression in the male germline is not required for proper sex determination and spermatogenesis, as functional sperm is differentiated by mutant germ cells in wild type hosts. However, somatic esg expression is required for the maintenance of male germline stem cells. PMID:11902678

Streit, Adrian; Bernasconi, Luca; Sergeev, Pavel; Cruz, Alex; Steinmann-Zwicky, Monica

2002-01-01

341

Epigenetics and sex differences in the brain: A genome-wide comparison of histone-3 lysine-4 trimethylation (H3K4me3) in male and female mice.  

PubMed

Many neurological and psychiatric disorders exhibit gender disparities, and sex differences in the brain likely explain some of these effects. Recent work in rodents points to a role for epigenetics in the development or maintenance of neural sex differences, although genome-wide studies have so far been lacking. Here we review the existing literature on epigenetics and brain sexual differentiation and present preliminary analyses on the genome-wide distribution of histone-3 lysine-4 trimethylation in a sexually dimorphic brain region in male and female mice. H3K4me3 is a histone mark primarily organized as 'peaks' surrounding the transcription start site of active genes. We microdissected the bed nucleus of the stria terminalis and preoptic area (BNST/POA) in adult male and female mice and used ChIP-Seq to compare the distribution of H3K4me3 throughout the genome. We found 248 genes and loci with a significant sex difference in H3K4me3. Of these, the majority (71%) had larger H3K4me3 peaks in females. Comparisons with existing databases indicate that genes and loci with increased H3K4me3 in females are associated with synaptic function and with expression atlases from related brain areas. Based on RT-PCR, only a minority of genes with a sex difference in H3K4me3 has detectable sex differences in expression at baseline conditions. Together with previous findings, our data suggest that there may be sex biases in the use of epigenetic marks. Such biases could underlie sex differences in vulnerabilities to drugs or diseases that disrupt specific epigenetic processes. PMID:25131640

Shen, Erica Y; Ahern, Todd H; Cheung, Iris; Straubhaar, Juerg; Dincer, Aslihan; Houston, Isaac; de Vries, Geert J; Akbarian, Schahram; Forger, Nancy G

2014-08-14

342

Developmental alterations of the C. elegans male anal depressor morphology and function require sex-specific cell autonomous and cell non-autonomous interactions.  

PubMed

We studied the Caenorhabditis elegans anal depressor development in larval males and hermaphrodites to address how a differentiated cell sex-specifically changes its morphology prior to adulthood. In both sexes, the larval anal depressor muscle is used for defecation behavior. However in the adult males, the muscle's sarcomere is reorganized to facilitate copulation. To address when the changes occur in the anal depressor, we used YFP:actin to monitor, and mutant analysis, laser-ablation and transgenic feminization to perturb the cell's morphological dynamics. In L1 and L2 stage larva, the muscle of both sexes has similar sarcomere morphology, but the hermaphrodite sex-determination system promotes more growth. The male anal depressor begins to change in the L3 stage, first by retracting its muscle arm from the neurons of the defecation circuit. Then the muscle's ventral region develops a slit that demarcates an anterior and posterior domain. This demarcation is not dependent on the anal depressor's intrinsic genetic sex, but is influenced by extrinsic interactions with the developing male sex muscles. However, subsequent changes are dependent on the cell's sex. In the L4 stage, the anterior domain first disassembles the dorsal-ventral sarcomere region and develops filopodia that elongates anteriorly towards the spicule muscles. Later, the posterior domain dissembles the remnants of its sarcomere, but still retains a vestigial attachment to the ventral body wall. Finally, the anterior domain attaches to the sex muscles, and then reassembles an anterior-posteriorly oriented sarcomere. Our work identifies key steps in the dimorphic re-sculpting of the anal depressor that are regulated by genetic sex and by cell-cell signaling. PMID:25498482

Chen, Xin; René García, L

2015-02-01

343

Determinants of parental care and offspring survival during the post-fledging period: males care more in a species with partially reversed sex roles.  

PubMed

Sexual conflict is magnified during the post-fledging period of birds when the sexes face different trade-offs between continuing parental care or investing in self maintenance or other mating opportunities. Species with reversed sex roles provide a unique opportunity to study the relationship between mating systems and investment in parental care. Here, we provide the first detailed study of the length of care by males versus females (n = 24 pairs) during the post-fledging period, assessing factors that may promote care within and between the sexes. In the northern flicker Colaptes auratus, a species with partly reversed sex roles, males cared longer than females (average 16 versus 12 days, respectively). Overall, 36% of females but no males deserted the brood prior to fledgling independence. Parents that provisioned nestlings at a high rate also spent more days feeding fledglings. Among males, age and nestling feeding rates were positively associated with the length of care. Among females, a low level of feather corticosterone (CORTf) was associated with a longer length of care. About 45% of fledglings died within the first week, but fledglings with intermediate body mass had the highest survival suggesting stabilizing selection on mass. Fledgling survival was also higher in individuals with larger broods and lower levels of CORTf. We demonstrate that because females can be polyandrous they often desert the brood before males, and that the sexes respond to different cues relating to their energy balance when deciding the length of care given to their offspring. PMID:24496554

Gow, Elizabeth A; Wiebe, Karen L

2014-05-01

344

RNAi-Mediated Gene Silencing in a Gonad Organ Culture to Study Sex Determination Mechanisms in Sea Turtle  

PubMed Central

The autosomal Sry-related gene, Sox9, encodes a transcription factor, which performs an important role in testis differentiation in mammals. In several reptiles, Sox9 is differentially expressed in gonads, showing a significant upregulation during the thermo-sensitive period (TSP) at the male-promoting temperature, consistent with the idea that SOX9 plays a central role in the male pathway. However, in spite of numerous studies, it remains unclear how SOX9 functions during this event. In the present work, we developed an RNAi-based method for silencing Sox9 in an in vitro gonad culture system for the sea turtle, Lepidochelys olivacea. Gonads were dissected as soon as the embryos entered the TSP and were maintained in organ culture. Transfection of siRNA resulted in the decrease of both Sox9 mRNA and protein. Furthermore, we found coordinated expression patterns for Sox9 and the anti-Müllerian hormone gene, Amh, suggesting that SOX9 could directly or indirectly regulate Amh expression, as it occurs in mammals. These results demonstrate an in vitro method to knockdown endogenous genes in gonads from a sea turtle, which represents a novel approach to investigate the roles of important genes involved in sex determination or differentiation pathways in species with temperature-dependent sex determination. PMID:24705165

Sifuentes-Romero, Itzel; Merchant-Larios, Horacio; Milton, Sarah L.; Moreno-Mendoza, Norma; Díaz-Hernández, Verónica; García-Gasca, Alejandra

2013-01-01

345

Heterogeneity of characteristics, structure, and dynamics of male and hijra sex workers in selected cities of Pakistan  

PubMed Central

Background We sought to describe the characteristics and operational dynamics of male sex workers (MSW) and hijra sex workers (HSWs) in 11 cities across Pakistan in 2011. Methods We report descriptive statistics of self-reported sexual behaviour data from cross-sectional mapping and biological and behavioural surveys conducted among 1431 MSWs and 1415 HSWs in four cities across Pakistan in 2011. Results While Karachi had the largest numbers of MSWs and HSWs, Quetta had the largest relative population sizes, with 3.6?MSWs per 1000 male adults and 3.3?HSWs per 1000 male adults. There was considerable variability in the proportion of HSWs who operate through deras, ranging from 2.2% in Peshawar to 62.7% in Karachi. The number of HSWs per guru varies by city, from 1.5 in Quetta to 16.5?HSWs per guru in Karachi. Among HSWs, the use of mobile phones for solicitation ranged from 37.6% in Quetta to 83% in Peshawar and among MSWs the use of mobile phones ranged from 27% in Karachi to 52% in Quetta. In Quetta, a large proportion of HSWs (41%) find clients through gurus. Client volume tended to be higher among HSWs and among both MSWs and HSWs in Quetta and Peshawar. Condom use with clients was most consistent in Quetta, with 31% of MSWs and 41% of HSWs reporting always using condoms with clients. Peshawar had the greatest proportion reporting never using condoms. Conclusions There is considerable geographic heterogeneity in the characteristics and operational dynamics of MSWs and HSWs across Pakistan. PMID:23605854

Thompson, Laura H; Salim, Momina; Baloch, Chaker Riaz; Musa, Nighat; Reza, Tahira; Dar, Nosheen; Arian, Shahzad; Blanchard, James F; Emmanuel, Faran

2013-01-01

346

The costs of being male: are there sex-specific effects of uniparental mitochondrial inheritance?  

PubMed

Eukaryotic cells typically contain numerous mitochondria, each with multiple copies of their own genome, the mtDNA. Uniparental transmission of mitochondria, usually via the mother, prevents the mixing of mtDNA from different individuals. While on the one hand, this should resolve the potential for selection for fast-replicating mtDNA variants that reduce organismal fitness, maternal inheritance will, in theory, come with another set of problems that are specifically relevant to males. Maternal inheritance implies that the mitochondrial genome is never transmitted through males, and thus selection can target only the mtDNA sequence when carried by females. A consequence is that mtDNA mutations that confer male-biased phenotypic expression will be prone to evade selection, and accumulate. Here, we review the evidence from the ecological, evolutionary and medical literature for male specificity of mtDNA mutations affecting fertility, health and ageing. While such effects have been discovered experimentally in the laboratory, their relevance to natural populations--including the human population--remains unclear. We suggest that the existence of male expression-biased mtDNA mutations is likely to be a broad phenomenon, but that these mutations remain cryptic owing to the presence of counter-adapted nuclear compensatory modifier mutations, which offset their deleterious effects. PMID:24864311

Beekman, Madeleine; Dowling, Damian K; Aanen, Duur K

2014-07-01

347

Nestsite selection by male loons leads to sex-biased site familiarity.  

PubMed

1. The concept that animals benefit from gaining familiarity with physical spaces is widespread among ecologists and constitutes a theoretical pillar in studies of territory defence, philopatry and habitat selection. Yet proximate causes and fitness benefits of site familiarity are poorly known. 2. We used data from marked common loons Gavia immer breeding on 98 territories over 14 years to investigate the 'win-stay, lose-switch rule' for nestsite placement (if eggs hatch, reuse nestsite; if predator takes eggs, move nestsite). Males controlled nest placement in this species: pairs used the rule if both members remained the same from the previous nesting attempt or if only the male remained the same but not if only the female remained the same. 3. By means of the nesting rule, male common loons benefited from site familiarity, increasing nesting success by 41% between their first and third years on a territory. In contrast, females exhibited no increase in nesting success with increased territorial tenure. 4. Owing to site familiarity, a male loon competing for a breeding territory faces a considerable 'familiarity deficit' compared with the male breeder already established there. The familiarity deficit probably explains why resident animals often fight hard to retain familiar territories, when challenged, and why animals of many species tend to remain on familiar territories rather than moving when territories of higher intrinsic quality become available nearby. PMID:17976165

Piper, Walter H; Walcott, Charles; Mager, John N; Spilker, Frank J

2008-03-01

348

Preferred and actual relative height among homosexual male partners vary with preferred dominance and sex role.  

PubMed

Previous research has shown repeatedly that human stature influences mate preferences and mate choice in heterosexuals. In general, it has been shown that tall men and average height women are most preferred by the opposite sex, and that both sexes prefer to be in a relationship where the man is taller than the woman. However, little is known about such partner preferences in homosexual individuals. Based on an online survey of a large sample of non-heterosexual men (N = 541), we found that the majority of men prefer a partner slightly taller than themselves. However, these preferences were dependent on the participant's own height, such that taller men preferred shorter partners, whereas shorter men preferred taller partners. We also examined whether height preferences predicted the preference for dominance and the adoption of particular sexual roles within a couple. Although a large proportion of men preferred to be in an egalitarian relationship with respect to preferred dominance (although not with respect to preferred sexual role), men that preferred a more dominant and more "active" sexual role preferred shorter partners, whereas those that preferred a more submissive and more "passive" sexual role preferred taller partners. Our results indicate that preferences for relative height in homosexual men are modulated by own height, preferred dominance and sex role, and do not simply resemble those of heterosexual women or men. PMID:24466136

Valentova, Jaroslava Varella; Stulp, Gert; T?ebický, Vít; Havlí?ek, Jan

2014-01-01

349

Preferred and Actual Relative Height among Homosexual Male Partners Vary with Preferred Dominance and Sex Role  

PubMed Central

Previous research has shown repeatedly that human stature influences mate preferences and mate choice in heterosexuals. In general, it has been shown that tall men and average height women are most preferred by the opposite sex, and that both sexes prefer to be in a relationship where the man is taller than the woman. However, little is known about such partner preferences in homosexual individuals. Based on an online survey of a large sample of non-heterosexual men (N?=?541), we found that the majority of men prefer a partner slightly taller than themselves. However, these preferences were dependent on the participant’s own height, such that taller men preferred shorter partners, whereas shorter men preferred taller partners. We also examined whether height preferences predicted the preference for dominance and the adoption of particular sexual roles within a couple. Although a large proportion of men preferred to be in an egalitarian relationship with respect to preferred dominance (although not with respect to preferred sexual role), men that preferred a more dominant and more “active” sexual role preferred shorter partners, whereas those that preferred a more submissive and more “passive” sexual role preferred taller partners. Our results indicate that preferences for relative height in homosexual men are modulated by own height, preferred dominance and sex role, and do not simply resemble those of heterosexual women or men. PMID:24466136

Valentova, Jaroslava Varella; Stulp, Gert; T?ebický, Vít; Havlí?ek, Jan

2014-01-01

350

Analysis of Male Pheromones That Accelerate Female Reproductive Organ Development  

PubMed Central

Male odors can influence a female's reproductive physiology. In the mouse, the odor of male urine results in an early onset of female puberty. Several volatile and protein pheromones have previously been reported to each account for this bioactivity. Here we bioassay inbred BALB/cJ females to study pheromone-accelerated uterine growth, a developmental hallmark of puberty. We evaluate the response of wild-type and mutant mice lacking a specialized sensory transduction channel, TrpC2, and find TrpC2 function to be necessary for pheromone-mediated uterine growth. We analyze the relative effectiveness of pheromones previously identified to accelerate puberty through direct bioassay and find none to significantly accelerate uterine growth in BALB/cJ females. Complementary to this analysis, we have devised a strategy of partial purification of the uterine growth bioactivity from male urine and applied it to purify bioactivity from three different laboratory strains. The biochemical characteristics of the active fraction of all three strains are inconsistent with that of previously known pheromones. When directly analyzed, we are unable to detect previously known pheromones in urine fractions that generate uterine growth. Our analysis indicates that pheromones emitted by males to advance female puberty remain to be identified. PMID:21347429

Flanagan, Kelly A.; Webb, William; Stowers, Lisa

2011-01-01

351

Female sex pheromone and male behavioral responses of the bombycid moth Trilocha varians: comparison with those of the domesticated silkmoth Bombyx mori.  

PubMed

Analysis of female sex pheromone components and subsequent field trap experiments demonstrated that the bombycid moth Trilocha varians uses a mixture of (E,Z)-10,12-hexadecadienal (bombykal) and (E,Z)-10,12-hexadecadienyl acetate (bombykyl acetate) as a sex pheromone. Both of these components are derivatives of (E,Z)-10,12-hexadecadienol (bombykol), the sex pheromone of the domesticated silkmoth Bombyx mori. This finding prompted us to compare the antennal and behavioral responses of T. varians and B. mori to bombykol, bombykal, and bombykyl acetate in detail. The antennae of T. varians males responded to bombykal and bombykyl acetate but not to bombykol, and males were attracted only when lures contained both bombykal and bombykyl acetate. In contrast, the antennae of B. mori males responded to all the three components. Behavioral analysis showed that B. mori males responded to neither bombykal nor bombykyl acetate. Meanwhile, the wing fluttering response of B. mori males to bombykol was strongly inhibited by bombykal and bombykyl acetate, thereby indicating that bombykal and bombykyl acetate act as behavioral antagonists for B. mori males. T. varians would serve as a reference species for B. mori in future investigations into the molecular mechanisms underlying the evolution of sex pheromone communication systems in bombycid moths. PMID:22307535

Daimon, Takaaki; Fujii, Takeshi; Yago, Masaya; Hsu, Yu-Feng; Nakajima, Yumiko; Fujii, Tsuguru; Katsuma, Susumu; Ishikawa, Yukio; Shimada, Toru

2012-03-01

352

Recombination between homologous autosomes in medfly (Ceratitis capitata) males: type-1 recombination and the implications for the stability of genetic sexing strains.  

PubMed

The sterile insect technique (SIT) is an environmentally safe technology to control insect pests. To improve this technology, genetic sexing strains (GSS) have been developed for the Mediterranean fruit fly, Ceratitis capitata. Such strains are based on Y-autosome translocations linking a selectable marker to the male sex and their long-term stability, especially under large-scale mass rearing conditions, is threatened by genetic recombination in the heterozygous males. We have measured male recombination in order to be able to construct GSS that are more stable. Our results show that male recombination occurs at very low frequencies, that is, below 1% per generation. Furthermore, recombination in medfly males occurs premeiotically. By selecting strains where the Y-autosome translocation breakpoint and the selectable marker are closely linked, the deleterious effects of recombination on the stability of GSS can be minimized. In such strains recombination is reduced by ca. 80% as compared to previously studied GSS. Although recombinants still occur at very low frequencies they still pose a threat to the integrity of the sexing system if they possess a selective advantage. Under mass rearing condition such recombinants will accumulate according to their relative fitness and additional measures, such as improved mass rearing strategies, are required to preserve the accuracy of the sexing system. As a conclusion it is shown that current GSS are stable enough to allow mass rearing at levels exceeding 1000 million male medflies per week. PMID:12484527

Franz, G

2002-09-01

353

Age, sex, reproduction, and spatial organization of lynxes colonizing northeastern Minnesota  

USGS Publications Warehouse

From 1972 through 1978, lynxes (Felis lynx) emigrating from Canada were studied in northeastern Minnesota. Fourteen individuals were radio-tracked, 8 wefe ear-tagged, and 49 carcasses were examined. Sex ratios of the samples were equal during the first years of the study, but females predominated later. At least half of the radiotagged lynxes were killed by humans; no natural mortality was detected. Home range sizes ranged from 51 to 122 km2 for females and 145 to 243 km2 for males, up to 10 times the sizes of those reported by other workers. Ranges of females tended to overlap. Males and females appeared to be segregated in the population.

Mech, L.D.

1980-01-01

354

Effects of steroid sex hormones on chick embryo gonads in organ culture, with special reference to hormonal control  

E-print Network

Effects of steroid sex hormones on chick embryo gonads in organ culture, with special reference to hormonal control of gonadal sex differentiation J. JORDANOV Pavlina ANGELOVA lnstitute of Morpho. At the initial stages of sex differentiation (7.5 and 8.5 days of incubation chick embryo gonads were treated

Paris-Sud XI, Université de

355

Effects of styrene monomer and trimer on gonadal sex differentiation of genetic males of the frog Rana rugosa.  

PubMed

To ascertain whether styrene monomer and trimer induce an estrogen-like effect, all-male tadpoles of Rana rugosa were exposed to dilute solutions of styrene monomer and trimer (2,4,6-tripfenyl-1-hexene) at concentrations of 0.1, 1, or 10 microM during days 19-23 after fertilization, which is the critical period of gonadal sex differentiation. As positive and vehicle controls, tadpoles were exposed to dilute solutions of estradiol-17beta at concentrations of 0.01, 0.1, or 1 microM and 0.01% ethanol, respectively, during the same period. The influence was estimated by examining the inner structure of the gonads of 40-day-old tadpoles. All the gonads of tadpoles in the vehicle and untreated controls showed histological characteristics of testes, whereas all those of tadpoles treated with 1 microM estradiol-17beta showed a structure typical for ovaries, having an ovarian sac and many meiotic germ cells. Of the genetically male tadpoles treated with styrene monomer and trimer, 97 and 96%, respectively, showed normal testicular structure of the gonads. In contrast, the remaining tadpoles had gonads showing coexistence of testicular and ovarian structure, irrespective of the strength of styrene concentration. These findings suggest that the styrene monomer and trimer induced a weak estrogen-like effect on the pathways of testicular differentiation in genetically male tadpoles. PMID:11771931

Ohtani, H; Ichikawa, Y; Iwamoto, E; Miura, I

2001-12-01

356

THE VOMERONASAL ORGAN IS REQUIRED FOR THE MALE MOUSE MEDIAL AMYGDALA RESPONSE TO CHEMICAL-COMMUNICATION  

E-print Network

THE VOMERONASAL ORGAN IS REQUIRED FOR THE MALE MOUSE MEDIAL AMYGDALA RESPONSE TO CHEMICAL chemical signals may be detected by the vomeronasal organ, which sends projections to the accessory of the chemical stimuli. However, regardless of biolog- ical relevance, vomeronasal organ removal eliminates all

Ronquist, Fredrik

357

Males' and females' conversational behavior in cross-sex dyads: From gender differences to gender similarities  

Microsoft Academic Search

We investigated gender differences in conversational behavior in an experimental setting. Twenty men and 20 women were randomly paired in 20 dyads and were asked to discuss a given topic. We examined the transcripts through a varied range of behavioral variables. First we analyzed the sequential ordering of utterances in order to establish the way male and female speakers take

Agnesa Pillon; Catherine Degauquier; François Duquesne

1992-01-01

358

On the Borders of Sexuality Research: Young People Who Have Sex with Both Males and Females  

ERIC Educational Resources Information Center

As D'Augelli and Grossman point out, there is an underrepresentation in LGB research of "youth who have had sexual experiences with both males and females." Most of the information on bisexuality has been obtained from studies with adult samples, and it is "unclear to what extent a separate bisexual cultural identity is consolidated during…

Pallotta-Chiarolli, Maria

2006-01-01

359

The Effects of Single-Sex Mathematics Classrooms on African American Males in the Ninth Grade  

ERIC Educational Resources Information Center

Research indicated that educators must consider socio-ecological accommodations because not all students learn in cooperative groups. Students must be taught how to discover the process of learning and to apply knowledge to real life situations. Gurian and Ballew (2003) identified differences in the male and female brain and the differences in how…

Faulkner-Simmons, Denise

2012-01-01

360

Night flight towards a sex pheromone source by male Spodoptera littoralis (Boisd.) (Lepidoptera, Noctuidae)  

Microsoft Academic Search

PHEROMONES have been used in population monitoring traps1 and in control by `confusion'2, and a good understanding of how the male finds the female is of great practical importance in the development of these techniques. The problem of insect orientation towards distant odour sources is also intrinsically interesting and much work has been done with wind tunnels to study the

J. Murlis; B. W. Bettany

1977-01-01

361

Anim. Behav., 1998, 55, 10031010 Context determines the sex appeal of male zebra finch song  

E-print Network

which sounds are most effective in inducing physiological changes leading to reproduction. 1998 induced reproduction in females. In a laboratory study, a rise in faecal oestrogen levels predicted egg The Association for the Study of Animal Behaviour There is a rich literature on the role of avian male song

362

The Stigmatized Woman: The Professional Woman in a Male Sex-Typed Career.  

ERIC Educational Resources Information Center

Applies Erving Goffman's stigma theory to impressions of 25 women in educational administration careers. Analyzes data from an earlier study to show how women administrators, confronted with male leadership norms, deviate, acquire stigma, and become marginal. Concludes with suggestions for change, citing 32 references. (MLH)

Marshall, Catherine

1985-01-01

363

Opinion: Sex, Gender and the Diagnosis of Autism--A Biosocial View of the Male Preponderance  

ERIC Educational Resources Information Center

Autism Spectrum Disorders (ASD) are behaviorally defined neurodevelopmental disorders. The best known yet less understood characteristic of autism is its unexplained male preponderance. Using a biosocial perspective, the goal of this article is to draw attention to the role of gender-based socialization practices and behavioral expectations during…

Goldman, Sylvie

2013-01-01

364

The effects of topiramate and sex hormones on energy balance of male and female rats  

Microsoft Academic Search

OBJECTIVE: The effects of topiramate (TPM) on components of energy balance were tested in male and female rats that were (i) left intact, (ii) castrated or (iii) castrated with replacement therapies consisting of testosterone administration in orchidectomized (OCX) rats and of estradiol or progesterone treatments in ovariectomized (OVX) rats.METHODS: TPM was mixed into the diet and administered at a dose

D Richard; F Picard; C Lemieux; J Lalonde; P Samson; Y Deshaies

2002-01-01

365

Effects of sex role attitudes and similarity on men's rejection of male homosexuals  

Microsoft Academic Search

Investigated 120 male undergraduates' reactions to homosexuals. Ss preselected on the basis of their profeminist, moderate, or antifeminist scores on the Attitude Toward Feminism Scale were assigned at random to 1 of 4 experimental conditions. Using a standard attraction paradigm design, Ss rated a bogus \\

Judith E. Krulewitz; Janet E. Nash

1980-01-01

366

Prenatal exposure to a low-frequency electromagnetic field demasculinizes adult scent marking behavior and increases accessory sex organ weights in rats  

SciTech Connect

Pregnant Sprague-Dawley dams were exposed to a low-level, low-frequency pulsed electromagnetic (EM) field (15 Hz, 0.3 msec duration, peak intensity 8 gauss) for 15 min twice a day from day 15 through day 20 of gestation, a period in development that is critical for sexual differentiation of the male rat brain. No differences in litter size, number of stillborns, or body weight were observed in offspring from field-exposed dams. At 120 days of age, field-exposed male offspring exhibited significantly less scent marking behavior than controls. Accessory sex organ weights, including epididymis, seminal vesicles, and prostate, were significantly higher in field-exposed subjects at this age. However, circulating levels of testosterone, luteinizing hormone, and follicle-stimulating hormone, as well as epididymal sperm counts, were normal. These data indicate that brief, intermittent exposure to low-frequency EM fields during the critical prenatal period for neurobehavioral sex differentiation can demasculinize male scent marking behavior and increase accessory sex organ weights in adulthood.

McGivern, R.F.; Sokol, R.Z.; Adey, W.R.

1990-01-01

367

Accumulation of toxic metals in male reproduction organs.  

PubMed

Occupation exposure to metals has been related to impaired reproduction in males. This report summarizes autoradiographic studies on the distribution of cadmium (Cd), chromium (Cr) and arsenic (As) in the testis and epididymis of rodents. Cd and Cr strongly accumulated in the interstitial tissues, indicating an effect on hormone production (Leydig cells) and blood supply or both. Arsenic accumulated in the lumen of the duct of epididymis causing long-term exposure of the semen. PMID:6595981

Danielsson, B R; Dencker, L; Lindgren, A; Tjälve, H

1984-01-01

368

Annual cycle of plasma luteinizing hormone and sex hormones in male and female mallards (Anas platyrhynchos)  

USGS Publications Warehouse

Comparisons between 'wild'and 'game farm' mallards (Anas platyrhynchos) were made to assess the differences in the temporal changes of plasma hormones. Seasonal variation in the levels of immunoreactive luteinizing hormone (LH), testosterone, 5 -dihydrotestosterone (DHT), estrone, estradiol-17i?? and progesterone were measured in male and female mallards. In all birds there was a vernal increase in the concentrations of LH and testosterone in plasma which were correlated with the development of the testes and ovaries prior to and during the nesting season. The concentrations of estrogens in the plasma of the females were, in general, slightly higher during the nesting season but were much lower than the levels of testosterone. The highest levels of LH and testosterone in the females coincided precisely with the period of egg laying which occurred approximately one month earlier in game farm females than in wild females. The concentrations of LH and testosterone in the plasma of females decreased rapidly during incubation. In wild males, the decline in levels of these hormones temporally coincided with that of females. In contrast, plasma levels of LH and testosterone of males of the game farm stock remained elevated after the beginning of incubation in females to which they were paired. On the basis of these results and an examination of the literature, it appears that domestication results in: 1) increased reproductive potential through earlier initiation of nesting and by delay of the termination of reproduction until later in the summer; and 2) a decrease in the synchronization of the hormonal events supporting reproduction between the male and female of a pair. Testicular weights and plasma levels of testosterone become higher in game farm and domestic males than in the wild stock but levels of LH are similar.

Donham, R.S.

1979-01-01

369

Inherited human sex reversal due to impaired nucleocytoplasmic trafficking of SRY defines a male transcriptional threshold  

PubMed Central

Human testis determination is initiated by SRY (sex determining region on Y chromosome). Mutations in SRY cause gonadal dysgenesis with female somatic phenotype. Two subtle variants (V60L and I90M in the high-mobility group box) define inherited alleles shared by an XY sterile daughter and fertile father. Whereas specific DNA binding and bending are unaffected in a rat embryonic pre-Sertoli cell line, the variants exhibited selective defects in nucleocytoplasmic shuttling due to impaired nuclear import (V60L; mediated by Exportin-4) or export (I90M; mediated by chromosome region maintenance 1). Decreased shuttling limits nuclear accumulation of phosphorylated (activated) SRY, in turn reducing occupancy of DNA sites regulating Sertoli-cell differentiation [the testis-specific SRY-box 9 (Sox9) enhancer]. Despite distinct patterns of biochemical and cell-biological perturbations, V60L and I90M each attenuated Sox9 expression in transient transfection assays by twofold. Such attenuation was also observed in studies of V60A, a clinical variant associated with ovotestes and hence ambiguity between divergent cell fates. This shared twofold threshold is reminiscent of autosomal syndromes of transcription-factor haploinsufficiency, including XY sex reversal associated with mutations in SOX9. Our results demonstrate that nucleocytoplasmic shuttling of SRY is necessary for robust initiation of testicular development. Although also characteristic of ungulate orthologs, such shuttling is not conserved among rodents wherein impaired nuclear export of the high-mobility group box and import-dependent phosphorylation are compensated by a microsatellite-associated transcriptional activation domain. Human sex reversal due to subtle defects in the nucleocytoplasmic shuttling of SRY suggests that its transcriptional activity lies near the edge of developmental ambiguity. PMID:24003159

Chen, Yen-Shan; Racca, Joseph D.; Phillips, Nelson B.; Weiss, Michael A.

2013-01-01

370

Sex of the cell dictates its response: differential gene expression and sensitivity to cell death inducing stress in male and female cells  

PubMed Central

Sexual dimorphisms are typically attributed to the hormonal differences arising once sex differentiation has occurred. However, in some sexually dimorphic diseases that differ in frequency but not severity, the differences cannot be logically connected to the sex hormones. Therefore, we asked whether any aspect of sexual dimorphism could be attributed to chromosomal rather than hormonal differences. Cells taken from mice at d 10.5 postconception (PC) before sexual differentiation, at d 17.5 PC after the first embryonic assertion of sexual hormones, and at postnatal day 17 (puberty) were cultured and exposed to 400 ?M ethanol or 20 ?M camptothecin or to infection with influenza A virus (multiplicity of infection of 5). The results showed that untreated male and female cells of the same age grew at similar rates and manifested similar morphology. However, they responded differently to the applied stressors, even before the production of fetal sex hormones. Furthermore, microarray and qPCR analyses of the whole 10.5 PC embryos also revealed differences in gene expression between male and female tissues. Likewise, the exposure of cells isolated from fetuses and adolescent mice to the stressors and/or sex hormones yielded expression patterns that reflected chromosomal sex, with ethanol feminizing male cells and masculinizing female cells. We conclude that cells differ innately according to sex irrespective of their history of exposure to sex hormones. These differences may have consequences in the course of sexually dimorphic diseases and their therapy.—Penaloza, C., Estevez, B., Orlanski, S., Sikorska, M., Walker, R., Smith, C., Smith, B., Lockshin R. A., Zakeri, Z. Sex of the cell dictates its response: differential gene expression and sensitivity to cell death inducing stress in male and female cells. PMID:19190082

Penaloza, Carlos; Estevez, Brian; Orlanski, Shari; Sikorska, Marianna; Walker, Roy; Smith, Catherine; Smith, Brandon; Lockshin, Richard A.; Zakeri, Zahra

2009-01-01

371

Quantitative variation in ecological and hormonal variables correlates with spatial organization of pronghorn ( Antilocapra americana ) males  

Microsoft Academic Search

Whereas variation in pronghorn (Antilocapra americana) spatial organization is well documented, underlying ecological or physiological explanations are not well understood. This\\u000a study quantitatively describes spacing systems of pronghorn males and correlates of their spatial organization. I collected\\u000a behavioral data from two populations in South Dakota (Wind Cave) and Montana (Bar Diamond) to determine if males differed\\u000a in space use, response

C. R. Maher

2000-01-01

372

Long-term follow-up of “sex change” in 13 male-to-female transsexuals  

Microsoft Academic Search

Thirteen male-to-female transsexuals were investigated in an intensive interview study. The follow-up period varied between 6 and 25 years, with an average of 12 years. Surgical outcome was disappointing, and only one-third of the patients where a vaginal construction was carried out had a functioning vagina. The importance of patient cooperation postoperatively is pointed out and reasons for noncooperation are

Gunnar Lindemalm; Dag Körlin; Nils Uddenberg

1986-01-01

373

(Patho)physiology of cross-sex hormone administration to transsexual people: the potential impact of male-female genetic differences.  

PubMed

There is a limited body of knowledge of desired and undesired effects of cross-sex hormones in transsexual people. Little attention has been given to the fact that chromosomal configurations, 46,XY in male-to-female transsexuals subjects (MtoF) and 46,XX in female-to-male transsexual subjects (FtoM), obviously, remain unchanged. These differences in their genomes cause sex differences in the functions of cells. This study reviews sex differences in metabolism/cardiovascular pathology, immune mechanisms, bone (patho)physiology and brain functions and examines whether they are, maybe partially, determined by genetic mechanisms rather than by (cross-sex) hormones. There do not appear to be major genetic impacts on the changes in bone physiology. Also immune functions are rather unaffected and the evidence for an increase of autoimmune disease in MtoF is preliminary. Brain functions of transsexuals may have differed from controls before cross-sex hormones; they do undergo shifts upon cross-sex hormone treatment, but there is no evidence for changes in sex-specific brain disease. The prevalence of cardiovascular disease is higher in MtoF receiving oestrogens than in FtoM receiving androgens. While type of oestrogen and route of administration might be significant, it is reasonable to speculate that nonhormonal/genetic factors play a role. PMID:25495275

Gooren, L J; Kreukels, B; Lapauw, B; Giltay, E J

2015-02-01

374

Condom Use Among Men Who Have Sex With Men and Male-to-Female Transgenders in Jakarta, Indonesia.  

PubMed

This article examined differences in condom use during anal intercourse among men who have sex with men (MSM) and male-to-female transgender women in Jakarta, Indonesia. A cross-sectional design, structured interviews, and hierarchical linear modeling were used to examine condom use among MSM recruited from entertainment places (EPs; e.g., discotheques/dance clubs/karaoke bars), massage parlors (MPs), and among transgender women who congregated and/or sought sexual partners on streets/parks (S/P). The sample consisted of 91, 97, and 114 of MSM-EP, MSM-MP, and transgender-S/P, respectively. Respondents reported on 641 unique sexual partner encounters, which were "nested" within 302 respondents. Reported condom use was high, 66%, 84%, and 83% for MSM-EP, MSM-MP, and transgender-S/P, respectively, and varied across type of respondent. At the individual level, depressive symptoms and history of physical abuse during childhood and adulthood were associated with lower condom use (p < .05). By contrast, having a higher level of education was associated with more condom use (p < .05). At the partner level, condom use was associated with type of partners and the use of club drugs before sex. HIV-prevention efforts should take into account the multilevel determinants of condom use within these populations. PMID:24203992

Safika, Iko; Johnson, Timothy P; Cho, Young Ik; Praptoraharjo, Ignatius

2013-11-01

375

Testicular disorder of sex development in four cats with a male karyotype (38,XY; SRY-positive).  

PubMed

The molecular background of disorders of sex development (DSD) in cats is poorly recognized. In this study we present cytogenetic, molecular and histological analyses of four cats subjected for the analysis due to ambiguous external genitalia. Three cases, with rudimentary penises and an abnormal position of the urethral orifice, represented different types of hypospadias. The fourth case had a normal penis, a blind vulva and spermatogenetically active testes. Histological studies showed structures typical of testes, but spermatogenic activity was observed in two cats only. All the cats had a normal male chromosome complement (38,XY) and the Y-chromosome linked genes (SRY and ZFY) were also detected. Fluorescent in situ hybridization (FISH), with the use of the feline BAC probe harboring the SRY gene, excluded the possibility of chromosome translocation of the Y chromosome fragment carrying the SRY gene onto another chromosome. Sequencing of four candidate genes (SRY--sex determining region Y; AR--androgen receptor; SRD5A2--steroid-5-alfa reductase 2 and MAMLD1--mastermind-like domain containing (1) revealed one SNP in the SRY gene, one common polymorphism in exon 1 of the AR gene (tandem repeat of a tri-nucleotide motif--CAG), six polymorphisms (5 SNPs and 1 indel) in the SRD5A2 gene and one SNP in the MAMLD1 gene. Molecular studies of the candidate genes showed no association with the identified polymorphisms, thus molecular background of the studied DSD phenotypes remains unknown. PMID:25455261

Nowacka-Woszuk, Joanna; Szczerbal, Izabela; Salamon, Sylwia; Kociucka, Beata; Jackowiak, Hanna; Prozorowska, Ewelina; Slaska, Brygida; Rozanska, Dorota; Orzelski, Maciej; Ochota, Malgorzata; Dzimira, Stanislaw; Lipiec, Magdalena; Nizanski, Wojciech; Switonski, Marek

2014-12-10

376

Female Sex Workers, Male Circumcision and HIV: A Qualitative Study of Their Understanding, Experience, and HIV Risk in Zambia  

PubMed Central

Several sub-Saharan African countries, including Zambia, have initiated national voluntary medical male circumcision (MC) programs to reduce HIV incidence. In-depth interviews were conducted with twenty female sex workers (FSWs) in Lusaka to examine their understanding of MC and experiences with circumcised clients. Knowledge of MC was derived primarily through informal sources, with very few FSWs reporting exposure to MC educational campaigns. MC was not widely believed to be protective against HIV, however it was viewed by some as protective against STIs. Three FSWs reported having sex with recently circumcised clients, and most reported that men often used their MC status to try to convince FSWs to forego condoms. Findings suggest that FSWs, already at high risk for HIV infection, may face additional pressure toward higher risk behavior as a result of MC. As MC services are expanded, programs should support FSWs' efforts to protect themselves by providing information about what MC can - and cannot - offer for HIV/STI infection prevention. PMID:23349745

Abbott, Sharon A.; Haberland, Nicole A.; Mulenga, Drosin M.; Hewett, Paul C.

2013-01-01

377

Are Female Sex Workers Able to Negotiate Condom Use with Male Clients? The Case of Mobile FSWs in Four High HIV Prevalence States of India  

PubMed Central

Introduction Condom promotion among female sex workers (FSWs) is a key intervention in India’s National AIDS Control Program. However, there is limited understanding of how FSWs negotiate condom use with male clients, particularly in the context of their mobility for sex work. The objective of this study is to examine the factors associated with the mobile FSWs’ ability to refuse unsafe sex and successfully negotiate condom use with unwilling male clients. Methods Data for 5498 mobile FSWs from a cross-sectional survey conducted in 22 districts of four states in southern India were analyzed. Questions assessed FSWs’ ability to refuse clients unprotected sex, convince unwilling clients for condom use and negotiate condom use in a new location. Logistic regression models were constructed to examine the association between socio-demographics, economic vulnerability, sex work practice, and program exposure and condom negotiation ability. Results A majority of FSWs (60%) reported the ability to refuse clients for unprotected sex, but less than one-fifth reported the ability to successfully convince an unwilling client to use a condom or to negotiate condom use in a new site. Younger and older mobile FSWs compared to those who were in the middle age group, those with longer sex work experience, with an income source other than sex work, with program exposure and who purchased condoms for use, reported the ability to refuse unprotected sex, to successfully negotiate condom use with unwilling clients and to do so at new sites. Conclusion FSWs need to be empowered to not only refuse unprotected sex but also to be able to motivate and convince unwilling clients for condom use, including those in new locations. In addition to focusing on condom promotion, interventions must address the factors that impact FSWs’ ability to negotiate condom use. PMID:23840806

Bharat, Shalini; Mahapatra, Bidhubhusan; Roy, Suchismita; Saggurti, Niranjan

2013-01-01

378

The Organization of Children's Same-Sex Peer Relationships.  

ERIC Educational Resources Information Center

Uses a sociometric analysis to explore the differential organization of boys' and girls' peer groups. Finds that boys structure their peer groups by creating a large central cluster composed of smaller integrated clusters, whereas girls form small clusters unrelated to one another. Nevertheless, girls are aware of and sensitive to the status of…

Benenson, Joyce; Apostoleris, Nicholas; Parnass, Jodi

1998-01-01

379

Disruption of male sex hormones with regard to pesticides: pathophysiological and regulatory aspects.  

PubMed

Several pesticides used as herbicides, insecticides and fungicides are known to be endocrine disrupting chemicals (EDCs). In three pair-matched studies we found changes in sex hormone concentrations and T-lymphocytes in relation to acute and chronic pesticide exposure. After acute exposure, 1 day later the concentrations of testosterone and especially estradiol decreased. T4- and T8-lymphocytes slightly increased. Effects of chronic occupational pesticide exposure were expressed by a higher level of testosterone and a larger ratio of T4-/T8-lymphocytes in comparison to control persons. Concentrations of LH in exposed men were higher after exposure than before. We assume an inhibition of the aromatase system by testosterone metabolites. The studies show two effects with regard to the duration of exposure: a hormonal and immune suppression after acute exposure and an activation of both systems following chronic exposure. PMID:10414800

Straube, E; Straube, W; Krüger, E; Bradatsch, M; Jacob-Meisel, M; Rose, H J

1999-06-30

380

Prenatal letrozole produces a subpopulation of male rats with same-sex preference and arousal as well as female sexual behavior.  

PubMed

Disruption of the sexual differentiation process during critical periods in male rodents produces changes in partner preference and sexual behavior. In this study we used prenatal (gestation days 10-22) letrozole (0.31 and 0.56 ?g/kg) to inhibit aromatase and alter normal sexual differentiation of males. These animals and control rats (injected with vehicle) were used when adults to study: a) sexual preference (where the experimental male could choose to interact with a receptive female or a sexually experienced male); b) masculine and feminine sexual behaviors (tested in cylindrical arenas); c) non-contact erections when exposed to a female or a male and, d) serum sex steroids and gonadotropin levels. The results showed that 30% of the males treated with letrozole (0.56 ?g/kg) had same-sex preference, 33% displayed lordosis and 63% showed non-contact erections in the presence of a sexually experienced male. However, 44% of these males also exhibited complete masculine sexual behavior towards receptive females. None of the control males displayed lordosis when mounted by another male and very few (12%) showed non-contact erections when exposed to a sexually experienced male. Similar low percentages were found in those males prenatally treated with the low letrozole dose (0.31 ?g/kg). No difference was found in the serum levels of testosterone, estradiol, LH and FSH between control and letrozole-treated males regardless of their sexual preference. These results indicate that prenatal selective inhibition of aromatization produces feminization of sexual partner preference, arousal and sexual behavior but does not affect masculine sexual behavior. PMID:25462593

Olvera-Hernández, Sandra; Chavira, Roberto; Fernández-Guasti, Alonso

2015-02-01

381

First record of the scarab beetle, Phyllophaga lissopyge from South America, with descriptions of adult seasonal activity and male response to sex attractants.  

PubMed

Phyllophaga lissopyge (Bates) (Coleoptera: Scarabaeidae: Melolonthinae) is reported for the first time from South America. Male sex pheromone response is described for P. lissopyge and two other co-occurring Phyllophaga species. Adults of P. lissopyge and P. menetriesi (Blanchard) flew to traps baited with methyl 2-(methylthio) benzoate whereas adults of P. obsoleta (Blanchard) flew irregularly to four different pheromone compounds. Adult seasonal activity is described from males captures in Rionegro, Antioquia, Colombia. PMID:21529153

Morales-Rodriguez, Anuar; Peck, Daniel C; Robbins, Paul S

2011-01-01

382

First Record of the Scarab Beetle, Phyllophaga lissopyge from South America, with Descriptions of Adult Seasonal Activity and Male Response to Sex Attractants  

PubMed Central

Phyllophaga lissopyge (Bates) (Coleoptera: Scarabaeidae: Melolonthinae) is reported for the first time from South America. Male sex pheromone response is described for P. lissopyge and two other co-occurring Phyllophaga species. Adults of P. lissopyge and P. menetriesi (Blanchard) flew to traps baited with methyl 2-(methylthio) benzoate whereas adults of P. obsoleta (Blanchard) flew irregularly to four different pheromone compounds. Adult seasonal activity is described from males captures in Rionegro, Antioquia, Colombia. PMID:21529153

Morales-Rodriguez, Anuar; Peck, Daniel C.; Robbins, Paul S.

2011-01-01

383

Male-Dependent Doubly Uniparental Inheritance of Mitochondrial DNA and Female-Dependent Sex-Ratio in the Mussel Mytilus Galloprovincialis  

PubMed Central

We have investigated sex ratio and mitochondrial DNA inheritance in pair-matings involving five female and five male individuals of the Mediterranean mussel Mytilus galloprovincialis. The percentage of male progeny varied widely among families and was found to be a characteristic of the female parent and independent of the male to which it was mated. Thus sex-ratio in Mytilus appears to be independent of the nuclear genotype of the sperm. With a few exceptions, doubly uniparental inheritance (DUI) of mtDNA was observed in all families fathered by four of the five males: female and male progeny contained the mother's mtDNA (the F genome), but males contained also the father's paternal mtDNA (the M genome). Two hermaphrodite individuals found among the progeny of these crosses contained the F mitochondrial genome in the female gonad and both the F and M genomes in the male gonad. All four families fathered by the fifth male showed the standard maternal inheritance (SMI) of animal mtDNA: both female and male progeny contained only the maternal mtDNA. These observations illustrate the intimate linkage between sex and mtDNA inheritance in species with DUI and suggest different major roles for each gender. We propose a model according to which development of a male gonad requires the presence in the early germ cells of an agent associated with sperm-derived mitochondria, these mitochondria are endowed with a paternally encoded replicative advantage through which they overcome their original minority in the fertilized egg and this advantage (and, therefore, the chance of an early entrance into the germ line) is countered by a maternally encoded egg factor. PMID:9093859

Saavedra, C.; Reyero, M. I.; Zouros, E.

1997-01-01

384

Male circumcision, alcohol use and unprotected sex among patrons of bars and taverns in rural areas of north-west province, South Africa.  

PubMed

Strong research evidence has shown that medical male circumcision significantly reduces heterosexual HIV acquisition among men. However, its effectiveness is enhanced by behavioural factors such as condom use. Currently, little is known of unprotected sex associated with male circumcision (MC) among alcohol-drinking tavern-going men, or whether engagement in unprotected sex may differ between men who have been traditionally circumcised and those who have been medically circumcised. The study sought to determine the relative importance of alcohol consumption and MC as correlates of unprotected sex and to compare the risk of engaging in unprotected sex between traditionally circumcised and medically circumcised tavern-going men from two rural villages in North-West province, South Africa. Data from 314 adult men (?18 years) were analysed. The men were recruited from four bars/taverns using systematic sampling. They responded to questions regarding their demographic characteristics, alcohol consumption, circumcision status and method (where applicable), and engagement in unprotected sex. Descriptive analyses and bivariate and multivariate logistic regression analyses were conducted. Age, education, relationship status, alcohol consumption and traditional male circumcision (TMC) were independently and significantly associated with unprotected sex. Specifically, probable alcohol dependence and traditional circumcision were independent risk factors for engaging in unprotected sex among tavern-going men. Traditionally circumcised men had a higher risk of engaging in unprotected sex than medically circumcised men. Interventions aimed at reducing alcohol consumption, encouraging protective behaviour among men who have undergone TMC, and increasing condom use are needed in bar/tavern settings. HIV prevention education must be urgently incorporated into TMC programmes. PMID:25428332

Nkosi, Sebenzile; Sikweyiya, Yandisa; Kekwaletswe, Connie T; Morojele, Neo K

2015-05-01

385

Unprotected sex among HIV-positive injection drug-using women and their serodiscordant male partners: role of personal and partnership influences.  

PubMed

We investigated the characteristics of human immunodeficiency virus (HIV)-positive injection drug-using women who reported unprotected vaginal and/or anal sex with HIV-negative or unknown serostatus (serodiscordant) male partners. Of 426 female study participants, 370 were sexually active. Of these women, 39% (144/370) and 40% (148/370) reported vaginal and/or anal sex with serodiscordant main and casual partners, respectively. Sixty percent of women inconsistently used condoms with their serodiscordant main partners, whereas 53% did so with casual partners. In multivariate analysis, during sex with main partners, inconsistent condom users were less likely to feel confident about achieving safe sex (self-efficacy), personal responsibility for limiting HIV transmission, and that their partner supported safe sex. Inconsistent condom use was also more likely among women who held negative beliefs about condoms and in couplings without mutual disclosure of HIV status. Regarding sex with casual partners, inconsistent condom users were more likely to experience psychologic distress, engage in sex trading, but they were less likely to feel confident about achieving safe sex. These findings suggest that there are widespread opportunities for the sexual transmission of HIV from drug-using women to HIV-uninfected men, and that reasons vary by type of partnership. Multifaceted interventions that address personal, dyadic, and addiction problems are needed for HIV-positive injection drug-using women. PMID:16760799

Latka, Mary H; Metsch, Lisa R; Mizuno, Yulo; Tobin, Karin; Mackenzie, Sonia; Arnsten, Julia H; Gourevitch, Marc N

2006-06-01

386

The role of the sex-determining region Y gene in the etiology of 46,XX maleness  

SciTech Connect

The condition of 46,XX maleness is characterized by testicular development in subjects who have two X chromosomes but who lack a normal Y chromosome. Several etiologies have been proposed to explain 46,XX maleness: (1) translocation of the testis-determining factor from the Y to the X chromosome, (2) mutation in an autosomal or X chromosome gene which permits testicular determination in the absence of TDF, and (3) undetected mosaicism with a Y-bearing cell line. The authors evaluated 10 affected subjects who were ascertained for different reasons and who had several distinct phenotypes. Six subjects had inherited sequences from the short arm of the Y chromosome including the sex-determining region Y gene (SRY). Five of the subjects were pubertal at the time of evaluation and had a phenotype similar to that of Klinefelter syndrome with evidence of Sertoli cell and Leydig cell dysfunction. One subject had evidence from Southern blot analysis and in situ hybridization for the presence of an intact Y chromosome in approximately 1% of cells. Three subjects lacked Y sequences by Southern blot analysis and by polymerase chain reaction amplification of SRY. These subjects were ascertained in the newborn period because of congenital anomalies. One had multiple anomalies including cardiac abnormalities; one had cardiac anomalies alone; and one had ambiguous genitalia. The data confirm the genetic heterogeneity of 46,XX maleness, in which some subjects have SRY while other subjects lack it. In addition, there is phenotypic heterogeneity among subjects who lack SRY suggesting that there is also genetic heterogeneity within this subgroup. 43 refs., 3 figs., 4 tabs.

Fechner, P.Y.; Marcantonio, S.M.; Jaswaney, V.; Stetten, G.; Migeon, C.J.; Smith, K.D.; Berkovitz, G.D. (Johns Hopkins Univ., Baltimore, MD (United States)); Goodfellow, P.N. (Imperial Cancer Research Fund, London (United Kingdom)); Amrhein, J.A. (Forbes Regional Health Center, Monroeville, PA (United States)); Bard, P.A. (Kaiser Permanente, Sacramento, CA (United States)); Lee, P.A. (Univ. of Pittsburgh, PA (United States)); Reid, C. (Robert Wood Johnson Medical School, Camden, NJ (United States)); Tsalikian, E. (Univ. of Iowa, Iowa City (United States)); Urban, M.D. (Wright State Univ., Dayton, OH (United States))

1993-03-01

387

Genetic Linkage in the Horse. II. Distribution of Male Recombination Estimates and the Influence of Age, Breed and Sex on Recombination Frequency  

PubMed Central

In the present study an extensive amount of data, comprising more than 30,000 offspring in total, was analyzed to evaluate the influence of age and sex on the recombination frequency in the K-PGD segment of the equine linkage group (LG) I and the influence of age, breed and sex on recombination in the Al-Es segment of LG II. A highly significant sex difference is reported for both segments. Male and female recombination values in the K-PGD segment were estimated at 25.8 ± 0.8 and 33.3 ± 2.5%, respectively. Similarly, recombination was less frequent in the male (36.6 ± 0.7%) than in the female (46.6 ± 1.2%) in the Al-Es segment. Comparison of data from two Swedish horse breeds revealed no significant breed differences in either sex for recombination in the Al-Es segment. No evidence of an age effect was found in any segment or sex. The distribution of individual male recombination estimates was also investigated, and a significant heterogeneity among stallions was revealed in the K-PGD segment. The results are discussed in relation to previous studies on factors affecting recombination in mammals. PMID:6693021

Andersson, Leif; Sandberg, Kaj

1984-01-01

388

Carotenoid-based ornaments of female and male American goldfinches (Spinus tristis) show sex-specific correlations with immune function and metabolic rate.  

PubMed

Conspicuous ornamentation has been linked to immunological and physiological condition in males of many species. In species where both sexes are ornamented, it is unclear whether the signal content of ornaments differs between males and females. We examined the immunological and physiological correlates of carotenoid-based bill and plumage ornamentation in American goldfinches Spinus tristis, a species in which bright orange bills are sexually monomorphic but yellow plumage is sexually dimorphic during the breeding season. Because bill color is dynamic over short periods while plumage color is static over longer time frames, we tested whether these signals have the potential to provide temporal information about immunity and condition. In both sexes, bill color (but not plumage color) was negatively related to leukocyte differential, a measure of recent stress, while plumage color (but not bill color) was positively related to resting metabolic rate. In females, bill color also positively correlated with immunoglobulin Y, a component of acquired immunity, while plumage color positively predicted natural antibody levels, a component of innate immunity. In males, neither bill color nor plumage color predicted immune function, suggesting that the mechanisms underlying these signals vary with sex. Our results demonstrate that dynamic signals such as bill coloration do not merely reflect the same information provided by static signals but that these two classes of signal provide information about different temporal aspects of phenotypic quality. Furthermore, our results indicate that a signal expressed in both sexes has the potential to provide different information depending on the sex of the bearer. PMID:22705485

Kelly, Ryan J; Murphy, Troy G; Tarvin, Keith A; Burness, Gary

2012-01-01

389

Comparison of Expressed Sequence Tags from Male and Female Sexual Organs of Marchantia polymorpha  

Microsoft Academic Search

A total of 935 expressed sequence tags (ESTs) from male immature sexual organ were determined, of which 600 ESTs were assembled into 110 non-redundant groups, resulting in 445 unique EST sequences. Of these, 244 sequences shared significant similarities to known nucleotide or amino acid sequences in other organisms. The remaining 201 unique sequences showed no significant matches and thus are

R. Nishiyama; Kenji MIURA; Megumi SAKAIDA; Sachiko OKADA; Kaoru KONO; Masayoshi TAKAHAMA; Takefumi SONE; Mizuki TAKENAKA; Hideya FUKUZAWA; Kanji OHYAMA

2000-01-01

390

Male Same Sex Couple Dynamics and Received Social Support for HIV Medication Adherence  

PubMed Central

This qualitative study examines received social support by analyzing relationship dynamics concerning antiretroviral therapy (ART) adherence among HIV+ seroconcordant and serodiscordant male couples. Using narrative data from forty participants (20 couples interviewed separately), we describe patterns of relationship dynamics and support preferences. One group viewed adherence as a Personal Responsibility. A second group viewed adherence as a Couple Responsibility and integrated support for medication adherence into the relationship. A third group was in the process of ending their relationships and adherence support was one-sided or withdrawn altogether. Examining support exchanges contexts at cultural, situational, relational, and personal levels illuminated adherence processes. Qualitative methods provided a framework for investigating these complex relationships and their associations with HIV treatment adherence. PMID:20651943

Wrubel, Judith; Stumbo, Scott; Johnson, Mallory O.

2010-01-01

391

RESEARCH Open Access Gender difference and sex hormone production  

E-print Network

RESEARCH Open Access Gender difference and sex hormone production in rodent renal ischemia a protective effect of female sex hormones in several organs subjected to ischemia-reperfusion injury. The aim of the study was to investigate sex hormone production in male rats after a renal ischemia-reperfusion sequence

Paris-Sud XI, Université de

392

Sex differences in the risk profile and male predominance in silent brain infarction in community-dwelling elderly subjects: the Sefuri brain MRI study  

Microsoft Academic Search

Although brain infarction is more common in men, the male predominance of silent brain infarction (SBI) was inconsistent in the earlier studies. This study was to examine the relationship between sex differences in the risk profile and SBI. We conducted a population-based, cross-sectional analysis of cardiovascular risk factors and SBI on MRI. We asked all the female participants about the

Yuki Takashima; Yoshikazu Miwa; Takahiro Mori; Manabu Hashimoto; Akira Uchino; Takefumi Yuzuriha; Toshiyuki Sasaguri; Hiroshi Yao

2010-01-01

393

Trends in Infectious Diseases and the Male to Female Ratio: Possible Clues to Changes in Behavior among Men Who Have Sex with Men  

ERIC Educational Resources Information Center

Men who have sex with men (MSM) are a priority population for HIV care and prevention programs. This report describes HIV and other sexually transmitted disease (STD) trends among MSM in metropolitan Atlanta by analyzing nine databases. We describe the use of the male-to-female (M:F) ratio, a surrogate marker for MSM in databases without…

Beltrami, John F.; Shouse, R. Luke; Blake, Paul A.

2005-01-01

394

Number of casual male sexual partners and associated factors among men who have sex with men: Results from the National HIV Behavioral Surveillance system  

PubMed Central

Background In 2006, the majority of new HIV infections were in MSM. We sought to describe numbers of casual sex partners among US MSM. Methods Data are from the first MSM cycle of the National HIV Behavioral Surveillance system, conducted from 2003 to 2005. Relationships between number of casual male sex partners within the previous year and demographic information, self-reported HIV status, and risk behaviors were determined through regression models. Results Among 11,191 sexually active MSM, 76% reported a casual male partner. The median casual partner number was three. Lower number of casual partners was associated with black race, Hispanic ethnicity, and having a main sex partner in the previous year. Factors associated with a higher number included gay identity, exchange sex, both injection and non-injection drug use. Being HIV-positive was associated with more partners among non-blacks only. Age differences in partner number were seen only among chat room users. Conclusions MSM who were black, Hispanic or had a main sex partner reported fewer casual sex partners. Our results suggest specific populations of MSM who may benefit most from interventions to reduce casual partner numbers. PMID:21439069

2011-01-01

395

Extremely female-biased primary sex ratio and precisely constant male production in a parasitoid wasp Melittobia  

Microsoft Academic Search

The study of sex allocation is one of the most productive areas in evolutionary biology, with considerable interplay between theoretical and empirical work. However, observed sex ratios are often measured after developmental periods and they may not reflect primary sex investment ratios, which is what theory predicts. We examined with the sex ratio behaviour of the parasitoid wasp Melittobia, in

Jun Abe; Yoshitaka Kamimura; Masakazu Shimada; Stuart A. West

2009-01-01

396

Structure of vomeronasal organ (Jacobson organ) in male Camelus Domesticus Var. dromedaris persica.  

PubMed

The vomeronasal organ (VNO) is a tubular structure in the roof of nasal cavity. The important role of this organ is olfaction of sexual odour. In this study, position, anatomical structure and histology of VNO in Iranian camels (camelus domesticus var. dromedaris persica) were determined. Fourteen healthy male camel heads were collected from an industrial slaughterhouse in Tehran, Iran, for anatomical and histological studies (seven each). The length of VNO and width of dental pad and the number and width of palatine crests were measured. For anatomical studies, the mandible was removed, and maxilla and nasal cavity was cut longitudinally and transversely. For histological studies, the mandible was removed, and first 0.5 cm of initial part of VNO was cut. Then, nasal cavity was cut in some segments with 2 cm thickness. The width of VNO was 3.85 ± 0.31 cm and 1.57 ± 0.18 cm in front and distal parts, respectively. The length of VNO was 15.61 ± 0.59 cm. In histological examinations, VNO was surrounded by J-shape hyaline cartilage. The lining epithelium of lateral wall of VNO was originated from respiratory epithelium, while it had an olfactory epithelium origin in the medial wall. Lamina propria and tunica submucosa were a cavernous connective tissue with seromucous gland with abundant of serous secretory units. The lumen of VNO opens into nasal cavity. The presence of olfactory epithelium found in our study indicates an important role for VNO in pheromone perception and beginning of sexual behaviour. PMID:24611976

Karimi, H; Mansoori Ale Hashem, R; Ardalani, G; Sadrkhanloo, R; Hayatgheibi, H

2014-12-01

397

Climate Influences Fledgling Sex Ratio and Sex-Specific Dispersal in a Seabird  

PubMed Central

Climate influences the dynamics of natural populations by direct effects over habitat quality but also modulating the phenotypic responses of organisms’ life-history traits. These responses may be different in males and females, particularly in dimorphic species, due to sex-specific requirements or constraints. Here, in a coastal seabird, the European shag (Phalacrocorax aristotelis), we studied the influence of climate (North Atlantic Oscillation, NAO; Sea Surface Temperature, SST) on two sex-related population parameters: fledgling sex ratio and sex-specific dispersal. We found that fledgling sex ratio was female skewed in NAO-positive years and male skewed in NAO-negative years. Accordingly, females dispersed a longer distance in NAO-positive years when females were overproduced, and on the contrary, males dispersed more in NAO-negative years. Overall, our findings provide rare evidence on vertebrates with genetic sex determination that climate conditions may govern population dynamics by affecting sex-specific density and dispersal. PMID:23951144

Barros, Álvaro; Álvarez, David; Velando, Alberto

2013-01-01

398

A homolog of male sex-determining factor SRY cooperates with a transposon-derived CENP-B protein to control sex-specific directed recombination  

PubMed Central

Schizosaccharomyces pombe cells switch mating type by replacing genetic information at the expressed mat1 locus with sequences copied from mat2-P or mat3-M silent donor loci. The choice of donor locus is dictated by cell type, such that mat2 is the preferred donor in M cells and mat3 is the preferred donor in P cells. Donor choice involves a recombination-promoting complex (RPC) containing Swi2 and Swi5. In P cells, the RPC localizes to a specific DNA element located adjacent to mat3, but in M cells it spreads across the silent mating-type region, including mat2-P. This differential distribution of the RPC regulates nonrandom choice of donors. However, cell-type–specific differences in RPC localization are not understood. Here we show that the mat1-M–encoded factor Mc, which shares structural and functional similarities with the male sex-determining factor SRY, is highly enriched at the swi2 and swi5 loci and promotes elevated levels of RPC components. Loss of Mc reduces Swi2 and Swi5 to levels comparable to those in P cells and disrupts RPC spreading across the mat2/3 region. Mc also localizes to loci expressed preferentially in M cells and to retrotransposon LTRs. We demonstrate that Mc localization at LTRs and at swi2 requires Abp1, a homolog of transposon-derived CENP-B protein and that loss of Abp1 impairs Swi2 protein expression and the donor choice mechanism. These results suggest that Mc modulates levels of recombination factors, which is important for mating-type donor selection and for the biased gene conversion observed during meiosis, where M cells serve as preferential donors of genetic information. PMID:22042869

Matsuda, Emiko; Sugioka-Sugiyama, Rie; Mizuguchi, Takeshi; Mehta, Sameet; Cui, Bowen; Grewal, Shiv I. S.

2011-01-01

399

Sex determination in cattle based on simultaneous amplification of a new male-specific DNA sequence and an autosomal locus using the same primers.  

PubMed

A PCR-based method for sex determination of bovine DNA samples and embryo biopsies is presented. Using only one primer pair both the male-specific sequence FBNY (127 bp) and a sex-independent control PCR-fragment, the microsatellite marker FBN17 (136-140 bp) are generated in the same PCR reaction. Synteny mapping assigned the male-specific sequence to bovine chromosome Y (BTA Y), whereas FBN17 was mapped to bovine chromosome 2. Localisation of FBNY on BTA Y was confirmed by fluorescence in hybridisation of two BAC clones containing the male-specific sequence. There was no amplification of the male-specific target sequence FBNY in sheep, pig, goat, mice, man, and several wild species of the tribe Bovini. The bovine male-specific fragment was detected in dilutions containing as little as 10 pg genomic DNA and in blastomeres from embryo biopsies. The PCR assay presented here does require neither restriction endonuclease digestion of the PCR product nor additional nested PCR steps. Owing to the advantage of parallel amplification of the autosomal locus FBN17 no additional control fragment is necessary to detect PCR failure. The results of sex determination in embryo biopsies using FBNY were in agreement with the outcome from a reference assay used in commercial breeding programs. PMID:11550263

Weikard, R; Kühn, C; Brunner, R M; Roschlau, D; Pitra, C; Laurent, P; Schwerin, M

2001-09-01

400

Do Male and Female Cowbirds See Their World Differently? Implications for Sex Differences in the Sensory System of an Avian Brood Parasite  

PubMed Central

Background Male and female avian brood parasites are subject to different selection pressures: males compete for mates but do not provide parental care or territories and only females locate hosts to lay eggs. This sex difference may affect brain architecture in some avian brood parasites, but relatively little is known about their sensory systems and behaviors used to obtain sensory information. Our goal was to study the visual resolution and visual information gathering behavior (i.e., scanning) of brown-headed cowbirds. Methodology/Principal Findings We measured the density of single cone photoreceptors, associated with chromatic vision, and double cone photoreceptors, associated with motion detection and achromatic vision. We also measured head movement rates, as indicators of visual information gathering behavior, when exposed to an object. We found that females had significantly lower density of single and double cones than males around the fovea and in the periphery of the retina. Additionally, females had significantly higher head-movement rates than males. Conclusions Overall, we suggest that female cowbirds have lower chromatic and achromatic visual resolution than males (without sex differences in visual contrast perception). Females might compensate for the lower visual resolution by gazing alternatively with both foveae in quicker succession than males, increasing their head movement rates. However, other physiological factors may have influenced the behavioral differences observed. Our results bring up relevant questions about the sensory basis of sex differences in behavior. One possibility is that female and male cowbirds differentially allocate costly sensory resources, as a recent study found that females actually have greater auditory resolution than males. PMID:23544049

Fernández-Juricic, Esteban; Ojeda, Agustin; Deisher, Marcella; Burry, Brianna; Baumhardt, Patrice; Stark, Amy; Elmore, Amanda G.; Ensminger, Amanda L.

2013-01-01

401

The gross and micro anatomy of the accessory sex glands of the male agouti (Dasyprocta leporina).  

PubMed

This study was a follow up to the study on the gross anatomy of the male agouti (Dasyprocta leporina) reproductive system. The seminal vesicles of the agouti are lobulated structures. The mean diameter of the large lumen is 883.6 +/- 76.83 microm. The mucosa (24.1 +/- 0.92 microm), which is lined by pseudo-stratified columnar epithelium is thrown into folds, which often branch. The lamina muscularis mucosa is thin and is made of loose connective tissue containing blood vessels. The mucosa of the leaf-like coagulating glands of the agouti is folded. The mean diameter of the lumen is 488.3 +/- 41.96 microm. The mucosa contains tubuloalveolar glands, which have a mean length of 199.5 +/- 28.83 microm. The thin epithelium, 15.0 +/- 1.25-microm wide, consists mostly of pseudo-stratified columnar cells. The epithelium also has surface modifications in the form of apical blebs and cilia. The epithelium of the agouti's lobulated prostate gland is also folded creating a large lumen with a mean diameter of 995.5 +/- 55.70 microm. The mucosa contains tubular and tubuloalveolar glands, each having a mean length of 134.4 +/- 13.59 microm. The epithelium (13.9 +/- 1.16 microm) consists of pseudo-stratified columnar cells. The pea-shaped bulbourethral gland (BG) of the agouti consists of convoluted tubular, mucous secretory units, which are irregularly shaped each with a mean length of 177.9 +/- 7.10 microm and a mean width of 63.5 +/- 3.97 microm. The BG of the agouti are ventro-lateral to the rectum and dorsally positioned to the pubic symphysis, and connected to the urethra by short ducts. PMID:19007350

Mollineau, W M; Adogwa, A O; Garcia, G W

2009-06-01

402

Sex Differences in Lopinavir (LPV) and Ritonavir (RTV) Pharmacokinetics (PKs) Among HIV-infected Females and Males  

PubMed Central

Objectives We compared the pharmacokinetics of lopinavir (LPV) and ritonavir (RTV) between female and males. Methods This two-step, multicenter, pharmacokinetic study enrolled HIV-infected adults on lopinavir/ritonavir (LPV/r) capsules (400/100mg BID) plus 1 or more NRTIs. All subjects underwent 12 hour pharmacokinetic sampling. The PK sampling was repeated in subjects receiving the LPV/r tablet formulation. Results Step 1 enrolled 37 women and 40 men; step 2 included 42 subjects from step 1 plus 35 new participants (39 women and 38 men). LPV pharmacokinetics in females and males were not significantly different with either formulation. Females had significantly higher median RTV AUC0–12h with both the soft gel capsule and tablet formulations (SGC:5395 vs. 4119 ng*hr/ml, p=0.026; tablet 5310 vs. 3941 ng*hr/ml, p=0.012), higher median Cmax (SGC:802 vs. 635 ng/mL, p=0.032; tablet: 773 vs. 570 ng/ml, p=0.006)) and lower median CL/F (SGC:18.54 vs. 24.31 L/hour, p=0.026; tablet: 18.83 vs. 25.37 L/hour, p=0.012). RTV CL/F was slower in females after weight adjustment with both formulations. Conclusion The pharmacokinetics of LPV in the SGC and tablet formulations are comparable in HIV infected subjects. Females had higher RTV AUC0–12h and lower CL/F with both formulations. The mechanism of the sex difference in RTV CL/F warrants elucidation. PMID:21233301

Umeh, OC; Currier, JS; Park, JG; Cramer, Y; Hermes, AE; Fletcher, CV

2012-01-01

403

Peak Biomechanical Variables During Bilateral Drop Landings: Comparisons Between Sex (Female/Male) and Fatigue (Pre-Fatigue/Post-Fatigue)  

PubMed Central

Background Although anterior cruciate ligament (ACL) sprains usually occur during the initial phase of the landing cycle (less than 40° knee flexion), the literature has focused on peak values of knee angles, vertical ground reaction force (VGRF), and muscle activity even though it is unclear what occurs during the initial phase of landing. Objectives The objectives of this study were to determine the effects of sex (male and female) and fatigue (prefatigue/post-fatigue) on knee flexion angles at the occurrence of peak values of biomechanical variables [knee valgus angle, VGRF, and normalized electromyographic amplitude (NEMG) of the quadriceps and hamstring muscles] during a bilateral drop landing task. Methods Knee valgus angle, VGRF, and NEMG of the quadricep and hamstring muscles were collected during bilateral drop landings for twenty-nine recreational athletes before and after a fatigue protocol. Results Peak values of knee valgus, VGRF, and NEMG of medial and lateral hamstring muscles occurred during the late phase of the landing cycle (>40° of knee flexion). Females in the post-fatigue condition exhibited peak VGRF at significantly less knee flexion than in the pre-fatigue condition. Males in the post-fatigue condition exhibited peak lateral hamstring muscles NEMG at significantly higher knee flexion than in the pre-fatigue condition. Discussion and Conclusion Peak values of biomechanical variables that have been previously linked to ACL injury did not occur during the initial phase of landing when ACL injuries occur. No biomechanical variables peaked during the initial phase of landing; therefore, peak values may not be an optimal indicator of the biomechanical factors leading to ACL injury during landing tasks. PMID:21509113

Hagins, Marshall; Sheikhzadeh, Ali; Nordin, Margareta; Rose, Donald

2009-01-01

404

The Earliest Case of Extreme Sexual Display with Exaggerated Male Organs by Two Middle Jurassic Mecopterans  

PubMed Central

Background Many extant male animals exhibit exaggerated body parts for display, defense or offence in sexual selection, such as male birds of paradise showing off colorful and elegant feathers and male moose and reindeers bearing large structured antlers. For insects, male rhinoceros and stag beetles have huge horn-like structure for fighting and competition and some male Leptopanorpa scorpionflies have very long abdominal terminal segments for sexual display and competition. Fossil records of insects having exaggerated body parts for sexual display are fairly rare. One example is two male holcorpids with elongate abdominal segments from sixth (A6) to eighth (A8) and enlarged male genitalia from Eocene, suggesting evolution of these characters occurred fairly late. Principal Findings We document two mecopterans with exaggerated male body parts from the late Middle Jurassic Jiulongshan Formation in northeastern China. Both have extremely extended abdominal segments from A6 to A8 and enlarged genitalia, which might have been used for sexual display and, to less extent, for fighting with other males in the competition for mates. Although Fortiholcorpa paradoxa gen. et sp. nov. and Miriholcorpa forcipata gen. et sp. nov. seem to have affinities with Holcorpidae, we deem both as Family Incertae sedis mainly due to significant differences in branching pattern of Media (M) veins and relative length of A8 for F. paradoxa, and indiscernible preservation of 5-branched M veins in hind wing for M. forcipata. Conclusions/Significance These two new taxa have extended the records of exaggerated male body parts of mecopterans for sexual display and/or selection from the Early Eocene to the late Middle Jurassic. The similar character present in some Leptopanorpa of Panorpidae suggests that the sexual display and/or sexual selection due to extremely elongated male abdominal and sexual organs outweigh the negative impact of bulky body and poor mobility in the evolutionary process. PMID:23977031

Wang, Qi; Shih, Chungkun; Ren, Dong

2013-01-01

405

Estrogen receptor-alpha distribution in male rodents is associated with social organization.  

PubMed

It has been hypothesized that site-specific reduction of estrogen receptor-alpha (ERalpha) is associated with the expression of male prosocial behaviors. Specifically, highly social males are predicted to express significantly lower levels of ERalpha than females and less social males in brain regions associated with prosocial behavior including the bed nucleus of the stria terminalis (BST) and the medial amygdala (MeA). This hypothesis was tested by comparing ERalpha immunoreactivity (IR) in three species of microtines, the polygynous montane (Microtus montanus) and meadow (M. pennsylvanicus) voles and the monogamous pine vole (M. pinetorum), and two species of cricetines that differ in the extent of social pair-bond formation, Siberian (Phodopus sungorus) and Djungarian (P. campbelli) hamsters. As predicted, ERalpha-IR was sexually dimorphic in the BST and MeA of the highly social species, with females expressing more ERalpha-IR cells than males. Male and female montane voles did not differ. Male and female meadow voles differed in the ventromedial hypothalamus, with females expressing more ERalpha-IR cells. Male pine voles expressed lower levels of ERalpha-IR in the MeA than male montane and meadow voles and in the BST relative to montane males. Male Djungarian hamsters, which show higher levels of parental care, had fewer ERalpha-IR cells in the BST than male Siberian hamsters. Results indicate that the distribution of ERalpha differs relative to the continuum of species-typical affiliative behavior and supports the hypothesis that ERalpha has a significant role in regulating species-specific social organization. PMID:16374794

Cushing, Bruce S; Wynne-Edwards, Katherine E

2006-02-01

406

Sex Workers, Fem Queens, and Cross-Dressers: Differential Marginalizations and HIV Vulnerabilities Among Three Ethnocultural Male-to-Female Transgender Communities in New York City  

PubMed Central

This article describes 3 distinct ethnocultural male-to-female transgender communities in New York City: the low-income African American/Black1 and Latina(o) House Ball community; low-income, often undocumented immigrant Asian sex workers; and middle-class White cross-dressers. These communities are highly socially isolated from each other and are more connected to their ethnocultural contexts than to an abstract and shared transgender identity. Whereas previous research either has viewed male-to-female transgender people as one monolithic group or has separated them into abstract racial categories unconnected to their communities and lifestyles, this article positions them within specific social networks, cultures, neighborhoods, and lifestyles. With regard to HIV vulnerabilities, violence, and rape, House Ball community members seemed to engage in the riskiest form of survival sex work, whereas Asian sex workers seemed to engage in moderate-risk survival sex work. White cross-dressers seemed to engage in very low-risk recreational sex work.2 PMID:19079558

Hwahng, Sel Julian; Nuttbrock, Larry

2008-01-01

407

Personal or relational? Examining sexual health in the context of HIV serodiscordant same-sex male couples  

PubMed Central

Couples’ ability to adopt a “we” orientation has been associated with optimal health outcomes. This study examined how personal and relational motivations are uniquely associated with unprotected anal intercourse (UAI), protected anal intercourse (PAI), and the absence of sexual activity within HIV-serodiscordant same-sex male couples. HIV-positive men and their HIV-negative partners (n = 116 couples, 232 men) completed questionnaires and HIV-positive men had blood drawn for viral load. Results of a multinomial logistic regression illustrated that sexual satisfaction was positively associated with PAI among HIV-negative partners and negatively associated with PAI among HIV-positive partners. Endorsing a “we” orientation was positively associated with PAI among HIV-positive partners. Findings suggest that HIV-positive partners who espouse a “we” orientation may be willing to forgo their personal interests to protect their HIV-negative partners from HIV transmission. Couples-based interventions are warranted to help strengthen relationship dynamics to enhance the sexual health of serodiscordant couples. PMID:23636681

Gamarel, K.E.; Starks, T.J; Dilworth, S.E.; Neilands, T.B.; Taylor, J.M.; Johnson, M.O.

2014-01-01

408

The histone demethylase Dmel\\Kdm4A controls genes required for lifespan and male-specific sex-determination in Drosophila  

PubMed Central

Histone methylation plays an important role in regulating chromatin-mediated gene control and epigenetic-based memory systems that direct cell fate. Enzymes termed histone demethylases directly remove the methyl marks from histones, thus contributing to a dynamically regulated histone methylated genome, however the biological functions of these newly identified enzymes remains unclear. The JMJD2A-D family belongs to the JmjC domain-containing family of histone demethylases (JHDMs). Here, we report the cloning and functional characterization of the Drosophila HDM gene Dmel\\Kdm4A that is a homolog of the human JMJD2 family. We show that homologs for three human JHDM families, JHDM1, JHDM2 and JMJD2 are present in Drosophila and that are each expressed during the Drosophila lifecycle. Disruption of Dmel\\Kdm4A results in a reduction of the male lifespan and a male-specific wing extension/twitching phenotype that occurs in response to other males, and is reminiscent of an inter-male courtship phenotype involving the courtship song. Remarkably, certain genes associated with each of these phenotypes are significantly downregulated in response to Dmel\\Kdm4A loss, most notably the longevity associated Hsp22 gene and the male sex-determination fruitless gene. Our results have implications for the role of the epigenetic regulator Dmel\\Kdm4A in the control of genes involved in lifespan and male-specific sex-determination in the fly. PMID:19786080

Lorbeck, Meridith T.; Singh, Neetu; Zervos, Ashley; Dhatta, Madhusmitta; Lapchenko, Maria; Yang, Chen; Elefant, Felice

2009-01-01

409

Rat RFamide-related peptide-3 stimulates GH secretion, inhibits LH secretion, and has variable effects on sex behavior in the adult male rat.  

PubMed

A recently described avian neuropeptide, gonadotropin inhibitory hormone (GnIH), has been shown to have seasonal regulatory effects on the hypothalamic-pituitary-gonadotropin axis (HPG) in several avian species. In the bird, GnIH expression is increased during the photorefractory period and has inhibitory effects on the HPG. A recently described mammalian neuropeptide, RF-amide-related peptide-3 (RFRP-3), may be genetically related and functionally similar to this avian neuropeptide. The purposes of this study were to first see if rat RFRP-3 is expressed in the male rat brain and second to determine if ICV injections of RFRP-3 will have effects on feeding and sex behaviors, as well as hormone release from the anterior pituitary. Results confirm other studies in that immunoreactive cell bodies and fibers are observable in areas of the male rat brain known to control the HPG and feeding and sex behaviors. RFRP-3 fibers are also observed in close proximity to GnRH immunoreactive cell bodies. Behavioral tests indicate that high but not low ICV RFRP-3 (500 vs. 100 ng, respectively) significantly (p<0.05) suppressed all facets of male sex behavior while not having any observable effects on their ability to ambulate. Sex behavior was later exhibited when those same male rats received the ICV vehicle. While suppressing sex behavior, ICV RFRP-3 significantly (p<0.05) increased food intake compared to controls. ICV RFRP-3 also significantly reduced plasma levels of luteinizing hormone but increased growth hormone regardless of the time of day; however, at no time did RFRP-3 alter plasma levels of FSH, thyroid hormone, or cortisol. These results indicate that although RFRP-3 has similar effects on LH as observed with GnIH in avian species, in the rat RFRP-3 has additional roles in regulating feeding and growth. PMID:17113584

Johnson, Marlie A; Tsutsui, Kazuyoshi; Fraley, Gregory S

2007-01-01

410

DNA damage in organs of female and male mice exposed to nonylphenol, as a single agent or in combination with ionizing irradiation: a comet assay study.  

PubMed

The effect of nonylphenol (NP; either alone or in combination with ionizing radiation) on the induction of DNA strand breaks in mouse somatic cells has been examined. Male and female mice were repeatedly irradiated with X-rays (0.05 or 0.10 Gy), injected with NP (25 or 50mg/kg bw), or both (0.05 Gy+25 mg/kg bw NP or 0.10 Gy+50 mg/kg bw NP), for 2 weeks, 5 days/week. Liver, spleen, femora, lungs and kidneys were removed from each animal for the comet assay. NP-induced DNA damage differed, depending on organ and sex. In male mice, NP induced damage in all organs examined; in females, only the kidneys were affected. The effect of irradiation alone was similar in females and males. Combined exposure of males to 0.05 Gy+25 mg/kg bw NP significantly reduced the level of DNA strand breaks, compared to the controls and to 25mg/kg bw NP alone, in the majority of organs. The higher doses significantly increased damage to DNA in all organs examined. Combined exposure of females to low doses of both agents significantly enhanced damage to DNA in bone marrow lymphocytes and in cells of the liver and kidneys, compared to controls. At 0.10 Gy+50 mg/kg bw NP, DNA damage was increased in organs except liver and spleen. Although NP alone may not be mutagenic in female mice, its co-administration with irradiation may increase DNA damage in some organs. In contrast, in male mice, damage was reduced after combined irradiation-NP exposure, compared to NP alone. PMID:25308542

Dobrzy?ska, Ma?gorzata M

2014-09-15

411

Epidemiology of male same-sex behaviour and associated sexual health indicators in low- and middle-income countries: 2003–2007 estimates  

PubMed Central

Objectives: To conduct a systematic review of published and unpublished data from research and public health information systems on the prevalence of male-to-male sex in the total male population; as well as among men who have sex with men (MSM), data on prevalence of heterosexual activity and heterosexual unions; prevalence of condom use with male and female partners; and prevalence of HIV infection and other sexually transmitted infections (STIs). Methods: Key indicators were defined (a) among men in the general population: prevalence of sex with a man ever and last year; (b) among MSM: prevalence of heterosexual experiences ever and last year; proportion of male-female transgenders; proportion of sex workers; prevalence of HIV and other STIs, condom use in last sexual encounter; consistent condom use with men last year; never used a condom with a man. With help from key informants, study searches were conducted in Pubmed, LILLACS, institutional databases, conference records and other sources. Methodology and quality of information were assessed, and the best data available for 2003–7 were selected. Indicator estimates from each study were used to propose regional estimate ranges. Results: A total of 83 new entries were entered into the database in addition to the previous 561, totalling 644. Of these, 107 showing 2003–7 data were selected. Many new studies came from sub-Saharan Africa, portraying hidden HIV epidemics among MSM. The most frequently reported estimate was HIV infection, with high estimate ranges in most of the regions, except for Middle East and North Africa and Eastern Europe. The next most frequently reported was lifetime frequency of heterosexual sex, showing that roughly 50% of MSM ever had sex with a woman. The small number of newer studies reporting prevalence of “sex with a man in last 12 months” between 2003 and 2007, did not warrant enough new evidence to revise our 2005 size estimates for MSM populations. Conclusions: A considerable number of new studies with estimates of relevance to understanding sexual behaviour and HIV among MSM were identified, with an encouraging amount of new data coming from sub-Saharan Africa. However, limitations in the quality, utility and comparability of available information persist. At least three measures could be promoted for use in surveillance and academic studies: standardised indicators for MSM studies; standardised operational definitions of, and instructions to describe, variables; and standardised research designs and data gathering strategies. A prerequisite for this all is intense advocacy to ensure a social climate in which research into such matters is prioritised, resources are made available as needed and the human rights of MSM are respected. PMID:18647866

Cáceres, C F; Konda, K; Segura, E R; Lyerla, R

2008-01-01

412

Seasonal Specificity of Hormonal, Behavioral, and Coloration Responses to Within and Between-Sex Encounters in Male Lizards ( Sceloporus undulatus)  

Microsoft Academic Search

This study reports the gender and seasonal specificity of hormonal, behavioral, and coloration responses displayed by “resident” male lizards (Sceloporus undulatus) exposed to male or female “intruders” during staged encounters in outdoor enclosures. Resident males were engaged in staged encounters with males or females for 1 h per day on 9 consecutive days during the breeding and postbreeding seasons. Male-specific

Linda C. Smith; Henry B. John-Alder

1999-01-01

413

Effects of dibutyl phthalate as an environmental endocrine disruptor on gonadal sex differentiation of genetic males of the frog Rana rugosa.  

PubMed

To examine the effects of dibutyl phthalate (DBP) on gonadal sex differentiation, genetically male tadpoles of Rana rugosa were exposed to dilute solutions of DBP at concentrations of 0.1, 1, or 10 microM during days 19-23 after fertilization, which is the critical period of gonadal sex differentiation in R. rugosa. Tadpoles were necropsied on day 40. The genetically male tadpoles were produced from crossings between males (ZZ) of one local population, in which females are the heterogametic sex, and females (XX) of another local population, in which males are the heterogametic sex. As positive control groups, tadpoles were exposed to dilute solutions of 17beta-estradiol (E(2)) at concentrations of 0. 01, 0.1, or 1 microM during the same period. The internal structure of the gonads was histologically examined in a total of 30 control tadpoles, 86 E(2)-treated tadpoles, and 90 DBP-treated tadpoles. The gonads of the control tadpoles all showed the typical structure of testes. In contrast, 0.01, 0.1, and 1 microM E(2) treatments caused the undifferentiated gonads of 18, 63, and 100% of the tadpoles, respectively, to develop into gonads of complete or partial ovarian structure. After 0.1, 1, and 10 microM DBP treatment, 0, 7, and 17% of tadpoles, respectively, were similarly affected. These findings suggest that DBP was about 1,000-fold less potent than E(2). Nevertheless, DBP is an environmentally dangerous hormone that disrupts the pathways of testicular differentiation in genetically male animals. PMID:11133400

Ohtani, H; Miura, I; Ichikawa, Y

2000-12-01

414

Sex-Specific Genetic Structure and Social Organization in Central Asia: Insights from a Multi-Locus Study  

E-print Network

Sex-Specific Genetic Structure and Social Organization in Central Asia: Insights from a Multi-Locus Study Laure Se´gurel1 *, Begon~ a Marti´nez-Cruz1¤ , Lluis Quintana-Murci2 , Patricia Balaresque3 the maternally and paternally inherited genetic structure of human populations, and to infer sex

Paris-Sud XI, Université de

415

The chastity of amoebae: re-evaluating evidence for sex in amoeboid organisms  

PubMed Central

Amoebae are generally assumed to be asexual. We argue that this view is a relict of early classification schemes that lumped all amoebae together inside the ‘lower’ protozoa, separated from the ‘higher’ plants, animals and fungi. This artificial classification allowed microbial eukaryotes, including amoebae, to be dismissed as primitive, and implied that the biological rules and theories developed for macro-organisms need not apply to microbes. Eukaryotic diversity is made up of 70+ lineages, most of which are microbial. Plants, animals and fungi are nested among these microbial lineages. Thus, theories on the prevalence and maintenance of sex developed for macro-organisms should in fact apply to microbial eukaryotes, though the theories may need to be refined and generalized (e.g. to account for the variation in sexual strategies and prevalence of facultative sex in natural populations of many microbial eukaryotes). We use a revised phylogenetic framework to assess evidence for sex in several amoeboid lineages that are traditionally considered asexual, and we interpret this evidence in light of theories on the evolution of sex developed for macro-organisms. We emphasize that the limited data available for many lineages coupled with natural variation in microbial life cycles overestimate the extent of asexuality. Mapping sexuality onto the eukaryotic tree of life demonstrates that the majority of amoeboid lineages are, contrary to popular belief, anciently sexual, and that most asexual groups have probably arisen recently and independently. Additionally, several unusual genomic traits are prevalent in amoeboid lineages, including cyclic polyploidy, which may serve as alternative mechanisms to minimize the deleterious effects of asexuality. PMID:21429931

Lahr, Daniel J. G.; Parfrey, Laura Wegener; Mitchell, Edward A. D.; Katz, Laura A.; Lara, Enrique

2011-01-01

416

Age related modifications of soluble proteins in various organs of male garden lizard, Calotes versicolor  

Microsoft Academic Search

The oxidative modification of proteins measured as carbonyl derivatives increased with advancing age in the liver of male garden lizard. The same parameter did not show a significant change in other organs (brain, heart and kidney). Based on the observations in both homeotherms (mammals) and poikilotherms (insect and reptile), the in vivo oxidative modification of cellular proteins appears to be

B. S. Jena; S. Das; B. K. Patnaik

1996-01-01

417

Development of methods of male contraception: impact of the World Health Organization Task Force  

Microsoft Academic Search

ObjectiveTo give an historical record of the research of the World Health Organization (WHO) Task Force to develop methods of male contraception; to examine the social, political, medical, pharmaceutical, funding, and other factors that influenced progress; and to suggest reasons why such methods are only now becoming available.

Geoffrey M. H. Waites

2003-01-01

418

Improved technique to build surface models of the male urogenital organs from visible Korean  

Microsoft Academic Search

Purpose of this research is to present realistic surface models of male urogenital organs and neighboring structures, made more automatically by using new computer technique. For the purpose, outlining and automatic interpolation was performed on Combustion; surface reconstruction following volume reconstruction was done on 3D-Doctor; the surface models were assembled in their proper positions and refined on Maya; a surface

Min Suk Chung; Dong Sun Shin

2008-01-01

419

Expression of cysteine sulfinate decarboxylase (CSD) in male reproductive organs of mice.  

PubMed

Cysteine sulfinate decarboxylase (CSD) is the rate-limiting biosynthetic enzyme of taurine, but it is still controversial whether the male reproductive organs have the function to synthesize taurine through CSD pathway. The present study was thus undertaken to detect CSD expression in male mouse reproductive organs by RT-PCR, Western blot and immunohistochemistry. The results show that CSD is expressed both at the mRNA and protein levels in the testis, epididymis and ductus deferens. The relative levels of both CSD mRNA and protein increase from the testis to the epididymis and to the ductus deferens. Immunohistochemical results demonstrate that the main cell types containing CSD are Leydig cells of testis, epithelial cells and some stromal cells throughout the efferent ducts, epididymis and ductus deferens. These results suggest that male genital organs have the function to produce taurine through the CSD pathway, although quantifying the relation of CSD expression to taurine synthesis and the exact functions of taurine in male genital organs still need to be elucidated in future studies. PMID:16252094

Li, Jian Hua; Ling, Ya Qin; Fan, Jing Jing; Zhang, Xiao Ping; Cui, Sheng

2006-06-01

420

Co-occurrence of antisocial behavior and substance use: testing for sex differences in the impact of older male friends, low parental knowledge and friends' delinquency.  

PubMed

Delinquency and substance use (SU) are commonly comorbid during adolescence. In the present study we investigate this co-morbidity with 3 main objectives: 1. Evaluate reciprocal relationships between delinquency/SU across early adolescence. 2. Assess the impact of older male friends, low parental knowledge and friends' delinquency on subsequent development and inter-relationships of delinquency and SU. 3. Evaluate sex differences in these relationships. We applied cross-lagged structural equation models to the analysis of a longitudinal sample (n=3699). Findings demonstrated: (1) At ages 13-14 delinquency predicted SU more so than vice versa but effects became equal between ages 14 and 15. (2) Low parental knowledge and friends' delinquency predicted delinquency and SU. Older male friends predicted ASB. (3) Sex differences were present. For example, in the absence of antisocial friends low parent knowledge at age 12 indirectly predicted increased age 15 SU for girls more than boys. PMID:24636685

McAdams, Tom A; Salekin, Randall T; Marti, C Nathan; Lester, Whiney S; Barker, Edward D

2014-04-01