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Worse renal outcome of lupus nephritis in male patients: a case-control study

RESENDE, A. L.; TITAN, S. M.; BARROS, R. T.; WORONIK, V.
Fonte: SAGE PUBLICATIONS LTD Publicador: SAGE PUBLICATIONS LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.22%
Background: Progression and long-term renal outcome of lupus nephritis (LN) in male patients is a controversial subject in the literature. The aim of this study was to evaluate the influence of male gender on the renal outcome of LN. Methods: All male (M) LN patients who fulfilled American College of Rheumatology lupus criteria and who were referred for a kidney biopsy from 1999 to 2009 were enrolled in the study. Subjects with end-stage renal disease at baseline, or follow-up time below 6 months, were excluded. Cases were randomly matched to female (F) patients according to the class of LN, baseline estimated glomerular filtration rate (eGFR, Modification of Diet in Renal Disease simplified formula) and follow-up time. Treatment was decided by the clinical staff based on usual literature protocols. The primary endpoint was doubling of serum creatinine and/or end-stage renal disease. The secondary endpoint was defined as a variation of glomerular filtration rate (GFR) per year (Delta GFR/y index), calculated as the difference between final and initial eGFR adjusted by follow-up time for each patient. Results: We included 93 patients (31 M : 62 F). At baseline, M and F patients were not statistically different regarding WHO LN class (II 9.7%...

Male and female odors induce Fos expression in chemically defined neuronal population

DONATO JR., Jose; CAVALCANTE, Judney Cley; SILVA, Renata Juliana; TEIXEIRA, Aline Stavin; BITTENCOURT, Jackson Cioni; ELIAS, Carol Fuzeti
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.22%
Olfactory information modulates innate and social behaviors in rodents and other species. Studies have shown that the medial nucleus of the amygdala (MEA) and the ventral premammillary, nucleus (PMV) are recruited by conspecific odor stimulation. However, the chemical identity of these neurons is not determined. We exposed sexually inexperienced male rats to female or male odors and assessed Fos immunoreactivity (Fos-ir) in neurons expressing NADPH diaphorase activity (NADPHd, a nitric oxide synthase), neuropeptide Urocortin 3, or glutamic acid decarboxylase rnRNA (GAD-67, a GABA-synthesizing enzyme) in the MEA and PMV. Male and female odors elicited Fos-ir in the MEA and PMV neurons, but the number of Fos-immunoreactive neurons was higher following female odor exposure, in both nuclei. We found no difference in odor induced Fos-ir ill the MEA and PMV comparing fed and fasted animals. Ill the MEA, NADPHd neurons colocalized Fos-ir only in response to female odors. In addition, Urocortin 3 neurons comprise a distinct population and they do not express Fos-ir after conspecific odor stimulation. We found that 80% of neurons activated by male odors coexpressed GAD-67 mRNA. Following female odor, 50% of Fos neurons coexpressed GAD-67 rnRNA. The PMV expresses very little GAD-67...

Male dimorphism of a neotropical arachnid: harem size, sneaker opportunities, and gonadal investment

Munguia-Steyer, Roberto; Buzatto, Bruno A.; Machado, Glauco
Fonte: OXFORD UNIV PRESS INC; CARY Publicador: OXFORD UNIV PRESS INC; CARY
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.22%
Serracutisoma proximum is a harvestman with alternative male morphs. Large males use sexually dimorphic second legs in fights for the possession of territories on the vegetation, where females oviposit. Small males have short second legs and do not fight but rather sneak into the territories and copulate with egg-guarding females. We investigated the presence of male dimorphism across 10 populations of S. proximum, compared gonadal investment between male morphs, and assessed if the distribution of the sneakers is influenced by harem size. In all populations, there was male dimorphism, indicated by the bimodal distribution of the leg II length/body length. Gonadal investment did not differ between morphs and was not affected by male size, second leg length, and morph relative frequency in the populations. We found 361 territories, 90.0% containing 1 male, 9.7% containing 2 males (dyads), and 0.3% containing 3 males. The probability of encountering dyads increased with the number of females present in the territories. Moreover, the proportion of sneakers in territories containing dyads was higher than would be expected by chance. One possible reason for the ubiquity of alternative morphs in S. proximum could be the high mating opportunities experienced by sneakers in spatially structured populations with a resource defense polygyny system. Additionally...

Desenvolvimento reprodutivo de cabritas Saanen submetidas ao efeito macho no período peri-púbere; Reproductive development in Saanen goat kids subject to the male effect during the peri-pubertal period

Augusto, Laurinda
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 06/04/2015 PT
Relevância na Pesquisa
36.28%
O efeito macho, principal fator social associado a reprodução, é muito usado na estimulação da atividade cíclica durante o anestro em espécies sazonais. Há também referência da sua influência sobre a puberdade podendo acelerar idade em que esta ocorre, particularmente em suínos e ratos. O presente projeto tinha como objetivo estudar o efeito da exposição de cabritas Saanen peri-púbere ao efeito macho sobre o desenvolvimento reprodutivo em particular no padrão de comportamentos associados ao cio, perfil de estrógeno e progesterona e na expressão do gene kiss1, receptores de kisspeptinas, estrógeno e progesterona no hipotálamo, hipófise e ovário. No experimento 1, 29 cabritas Saanen entre 142,72 ± 10,61 dias idade e 24,9 ± 4,26 kg de peso, foram distribuídas aleatoriamente entre três tratamentos: 1) exposição ao macho sexualmente ativo (grupo macho); 2) exposição a fêmea androgenizada (grupo fêmea) e; 3) controle (grupo controle). Observação diária de comportamentos associados ao cio e coletas de sangue para determinação dos níveis de estradiol e progesterona foram realizadas de maio a outubro. Os grupos macho e fêmea registraram mais comportamentos associados ao cio que os animais do grupo controle. A interação social teve efeito sobre a posição da cauda...

Desempenho dos Questionários Massachusetts Male Aging Study (MMAS) e Androgen Deficiency in the Aging Male (ADAM) na predição da testosterona livre em pacientes com 40 anos ou mais atendidos em ambulatório de urologia; Performance of Massachusetts Male Aging Sudy (MMAS) and Androgen Deficiency in the Aging Male (ADAM) questionnaires in the prediction of free testosterone in patients aged 40 years or older treated in outpatient regimen

Cabral, Renan Desimon
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
36.25%
Objetivo: Atualmente, a medição de Testosterona Livre calculada é considerado como sendo o padrão-ouro no diagnóstico do hipogonadismo em homens, porém, não está disponível para todos os indivíduos com suspeita de diminuição da função testicular. Portanto, avaliamos se o questionário Adrogen Deficiency in the Aging Male (ADAM) e o questionário Massachusetts Male Ageing Study (MMAS) poderiam ser utilizados como substitutos das determinações bioquímicas na identificação de hipogonadismo em homens com 40 anos ou mais. Métodos: Foram analisados 460 homens, com 40 anos ou mais de idade, participantes voluntários do programa de rastreamento de câncer de próstata do Hospital de Clínicas de Porto Alegre. Foi avaliada a capacidade dos questionários ADAM e MMAS de identificar homens com níveis baixos de Testosterona Total, Livre Calculara e Biodisponível. Resultados: A sensibilidade e especificidade do questionário ADAM, com relação à Testosterona Livre Calculada, foram de 73,6% e 31,9%, respectivamente. O uso de ADAM resultou em uma classificação adequada da nossa população em indivíduos normais ou hipogonádicos em 52,75% dos casos. Para o questionário MMAS, a sensibilidade foi calculada em 59,9% e a especificidade em 42...

Neonatal inhalatory anesthetic exposure: Reproductive changes in male rats

Arena, A. C.; Pereira, O. C M
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 633-640
ENG
Relevância na Pesquisa
36.25%
We investigated the effects of an inhalatory anesthetic (ethyl ether) during the neonatal period of brain sexual differentiation on the later fertility and sexual behavior of male rats. Animals were exposed to ethyl ether immediately after birth. At adulthood, body weight, testes wet weight, and plasma testosterone levels were not affected; however, neonatal exposure to ether showed alterations on male fertility: a decrease in the number of spermatids and spermatozoa, an increase in the transit time of cauda epididymal spermatozoa and a decrease in daily sperm production. An alteration of sexual behavior was also observed: decreased male sexual behavior and appearance of homosexual behavior when the male rats were castrated and pretreated with exogenous estrogen. Probably, the ether delayed or reduced the testosterone peak of the sexual differentiation period, altering the processes of masculinization and defeminization of the hypothalamus. Our results indicate that perinatal exposure to ethyl ether during the critical period of male brain sexual differentiation, acting as endocrine disruptors, has a long-term effect on the fertility and sexual behavior of male rats, suggesting endocrine disruption through incomplete masculinization and defeminization of the central nervous system. © 2002 Elsevier B.V. All rights reserved.

Long-term effects of perinatal androgenization on reproductive parameters of male rat offspring androgenization and male rat reproduction

Guerra, M. T.; Perobelli, J. E.; Sanabria, M.; Anselmo-Franci, J. A.; De Grava Kempinas, W.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 586-592
ENG
Relevância na Pesquisa
36.22%
It is known that during sex differentiation, fetal androgens are critical determinants of the male phenotype. Although testosterone is necessary for normal development of male sexual behavior, perinatal androgen treatment can result in disruption of normal male sexual reproduction. Pregnant Wistar rats were administered either corn oil (vehicle) or testosterone propionate at 0.2 mg/kg from gestational day 12 until the end of lactation and the reproductive function of male offspring was evaluated at 90 (adulthood) and 270 (middle age) days of age. Perinatal androgenization in the rat provoked a reduction in sperm production and reserves in adulthood that did not affect fertility and did not persist at more advanced ages, as shown by the results at post-natal day 270. If perinatal androgenization promotes similar effects in humans of reproductive age, the results of the present work can impact male reproduction health, given the less efficient spermatogenesis and lower sperm reserves in the human epididymis, compared to rodents. © Georg Thieme Verlag KG Stuttgart. New York.

Phenotypic, cytogenetic and spike fertility characterization of a population of male-sterile triticale

Guerra,Divanilde; Pacheco,Marcelo Teixeira; Federizzi,Luiz Carlos
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2013 EN
Relevância na Pesquisa
36.27%
Triticale (X Triticosecale Wittmack) is a good cereal for production of flour and feed. A segregating population of triticale was developed from a male-sterile (MS) plant. To determine whether this new source of male sterility in triticale is appropriate for use in breeding programs the expression of the male sterility phenotype was characterized through spike fertility, meiotic behavior, and pollen. Controlled crosses between male-sterile plants and control varieties male-fertile (MF) of triticale were also conducted, and cytological analyses were performed in the F2 and backcross plants. Plants with male-sterile phenotypes displayed reduced spike fertility when compared to plants with male-fertile phenotypes. Compared to male-fertile plants, male-sterile plants exhibited a lower percentage of normal meiotic cells, a reduced meiotic index and reduced pollen viability. The F2 plants had improved pollen fertility when compared to the male-sterile population; however there were no corresponding improvements in the percentage of normal meiotic cells or in the meiotic index. A single generation of backcrosses resulted in an improved meiotic index and increased pollen viability. However, no changes in the percentage of normal meiotic cells were observed. Meiotic instability...

Identification of male factor infertility using a novel semen quality score and reactive oxygen species levels

Nallella,Kiran P.; Sharma,Rakesh K.; Allamaneni,Shyam S. R.; Agarwal,Ashok
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2005 EN
Relevância na Pesquisa
36.22%
PURPOSE: To determine whether patients with male factor infertility can be accurately identified by calculating a novel semen quality score and measuring levels of reactive oxygen species during routine infertility screening. METHODS: Semen samples from 133 patients and 91 healthy donors were evaluated with manual and computer-assisted semen analysis. A principal component analysis model was employed to calculate a semen quality score. In brief, this score was calculated by base 10 logarithms multiplied by varying weights given to 9 sperm parameters. Reactive oxygen species levels were measured using chemiluminescence assay. RESULTS: The semen quality score had a sensitivity of 80.45% and accuracy of 77% at a cutoff of 93.1 in identifying patients with male factor infertility. The area under the receiver operating characteristic curves for the semen quality score was 84.28% (95% CI: 65.22%-100%). Reactive oxygen species levels [log10 (reactive oxygen species +1)] were significantly higher in male factor infertility patients. Reactive oxygen species had a sensitivity of 83.47% and specificity of 60.52% with an accuracy of 75% at a cutoff of 1.25 in identifying male factor infertility patients. The area under the receiver operating characteristic curve for reactive oxygen species levels was 78.92% (95% CI: 72.60%-85.23%). semen quality scores were significantly and negatively correlated with reactive oxygen species levels in the donors and the male factor infertility patients. CONCLUSIONS: The semen quality score and reactive oxygen species levels in semen samples appear to be strongly associated with male factor infertility. Because both of these parameters are more sensitive than individual sperm parameters in identifying male factor infertility...

The Effect of male-male competition and its Underlying Regulatory Mechanisms on the Electric Signal of the Gymnotiform fish Brachyhypopomus gauderio

Salazar, Vielka Lineth
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
36.29%
Sexually-selected communication signals can be used by competing males to settle contests without incurring the costs of fighting. The ability to dynamically regulate the signal in a context-dependent manner can further minimize the costs of male aggressive interactions. Such is the case in the gymnotiform fish Brachyhypopomus gauderio, which, by coupling its electric organ discharge (EOD) waveform to endocrine systems with circadian, seasonal, and behavioral drivers, can regulate its signal to derive the greatest reproductive benefit. My dissertation research examined the functional role of the EOD plasticity observed in male B. gauderio and the physiological mechanisms that regulate the enhanced male EOD. To evaluate whether social competition drives the EOD changes observed during male-male interactions, I manipulated the number of males in breeding groups to create conditions that exemplified low and high competition and measured their EOD and steroid hormone levels. My results showed that social competition drives the enhancement of the EOD amplitude of male B. gauderio. In addition, changes in the EOD of males due to changes in their social environment were paralleled by changes in the levels of androgens and cortisol. I also examined the relationship between body size asymmetry...

Investigation of the role of oxidative stress in male infertility.

Tunc, Ozlem
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2011
Relevância na Pesquisa
36.26%
In recent years, there has been some suggestion of an increase in male factor infertility in the industrialized countries with a decline in sperm counts and a rise in sperm pathology. Male factor infertility is a multifactorial phenomenon that is observed in approximately half of infertile couples and affects one man in 20 in the general population. The potential causes of male infertility arise from a number of factors including genetic, lifestyle factors and chronic diseases. However, a high proportion of infertile male patients have now been shown to have defective sperm functions related to oxidative stress. Oxidative stress in semen has been speculated as one of the major factors causing male infertility and has been identified in 30-80% of cases of male infertility. While oxidative stress is accepted as a significant pathology, there is currently an inadequate knowledge of the exact mechanisms by which oxidative stress develops in male infertility, as well as a lack of an easy and reliable method for the measurement of seminal oxidative stress in routine clinical use. The main objective of this doctoral thesis is to investigate the underlying causes for oxidative stress in infertile men and the mechanisms by which oxidative stress develops. Furthermore it will also examine the effectiveness of an oral antioxidant therapy for treatment of seminal oxidative stress. During these doctoral studies experiments were designed with the aims of: • Developing a standardized protocol for the measurement of seminal oxidative stress...

Impact of obesity on male fertility, sperm function and molecular composition

Mc Pherson, N.; Bakos, H.; Fullston, T.; Lane, M.
Fonte: Landes Bioscience Publicador: Landes Bioscience
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
36.22%
Male obesity in reproductive-age men has nearly tripled in the past 30 y and coincides with an increase in male infertility worldwide. There is now emerging evidence that male obesity impacts negatively on male reproductive potential not only reducing sperm quality, but in particular altering the physical and molecular structure of germ cells in the testes and ultimately mature sperm. Recent data has shown that male obesity also impairs offspring metabolic and reproductive health suggesting that paternal health cues are transmitted to the next generation with the mediator mostly likely occurring via the sperm. Interestingly the molecular profile of germ cells in the testes and sperm from obese males is altered with changes to epigenetic modifiers. The increasing prevalence of male obesity calls for better public health awareness at the time of conception, with a better understanding of the molecular mechanism involved during spermatogenesis required along with the potential of interventions in reversing these deleterious effects. This review will focus on how male obesity affects fertility and sperm quality with a focus on proposed mechanisms and the potential reversibility of these adverse effects.; Nicole O. Palmer, Hasan W. Bakos...

Seven queer brothers : narratives of forbidden male same-sex desires from modernizing Finland 1894-1971

HAGMAN, Sandra
Fonte: Instituto Universitário Europeu Publicador: Instituto Universitário Europeu
Tipo: Tese de Doutorado
EN
Relevância na Pesquisa
36.22%
From 1894 to 1971, "same-sex fornication" was a crime in Finland. However, a wide variation can be seen in the degree to which same-sex relations were controlled during the existence of the law. From the 1930s onwards, the number of convictions started to rise, reaching its peak in the early 1950s and dropping sharply in the latter half of the 1960s. This research studied the ways in which male same-sex desire was perceived, controlled and lived through during the first seventy years of twentieth-century Finland. The longitudinal-type analysis provided the perspective to view the transformations in discourses on male sexual practices and their impact on actual policing. The research question was elaborated through the microhistorical narratives of seven men who had been convicted of same-sex fornication in different decades of the twentieth century. The theoretical basis of the dissertation was queer theory. The main sources were same-sex fornication court case documents which were read together with legal, medical and moral writings, and newspaper and tabloid articles. By combining micro- and macro-dimensions, the research was able to reveal the changing attitudes towards male sexual intimacy in Finnish society, and by comparison to European historiography the study showed the roots of these attitudes. Until the late 1920s...

Vicarious Exposure to Male Sexual Harassment: Correlates, Perceived Motives and Ethical Evaluations, & Behavioral Responses

Dionisi, ANGELA
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
36.28%
Despite the increasing attention given to the issue of sexual harassment by organizational scholars, important questions remain unanswered, particularly when it comes to the unique experiences of those who witness the sex-based mistreatment of their peers. Further still, as the sexual harassment of males has only recently captured the attention of researchers, much remains to be learned about situations involving this form of sexual harassment. My dissertation focuses on employees who witness the sex-based mistreatment of their male colleagues. More specifically, three studies focus on same-sex (male-on-male) and/or opposite-sex (female-on-male) male sexual harassment and the impact that observing this phenomenon has on female and male employees. First, I examine how witnessing the sexual harassment of a male colleague impacts one’s well-being, emotions, and collective self-esteem. Second, I investigate what observers of male sexual harassment believe motivates an aggressor to harass a male colleague, and how such beliefs are impacted by (a) the form of the harassment they witness, and (b) who perpetrates this harassment. Demonstrating what conditions will lead to an evaluation of a male sexual harassment incident as unethical is also a primary goal of this investigation. Last...

PMRD: a curated database for genes and mutants involved in plant male reproduction

Cui, X.; Wang, Q.; Yin, W.; Xu, H.; Wilson, Z.A.; Wei, C.; Pan, S.; Zhang, D.
Fonte: Biomed Central Publicador: Biomed Central
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
36.28%
BACKGROUND: Male reproduction is an essential biological event in the plant life cycle separating the diploid sporophyte and haploid gametophyte generations, which involves expression of approximately 20,000 genes. The control of male reproduction is also of economic importance for plant breeding and hybrid seed production. With the advent of forward and reverse genetics and genomic technologies, a large number of male reproduction-related genes have been identified. Thus it is extremely challenging for individual researchers to systematically collect, and continually update, all the available information on genes and mutants related to plant male reproduction. The aim of this study is to manually curate such gene and mutant information and provide a web-accessible resource to facilitate the effective study of plant male reproduction. DESCRIPTION: Plant Male Reproduction Database (PMRD) is a comprehensive resource for browsing and retrieving knowledge on genes and mutants related to plant male reproduction. It is based upon literature and biological databases and includes 506 male sterile genes and 484 mutants with defects of male reproduction from a variety of plant species. Based on Gene Ontology (GO) annotations and literature, information relating to a further 3697 male reproduction related genes were systematically collected and included...

Identificação de pacientes portadores do fator de infertilidade masculina através do cálculo de um novo escore de qualidade de sêmen e pela medida de espécies reativas de oxigênio; Identification of male factor infertility using a novel semen quality score and reactive oxygen species levels

Nallella, Kiran P.; Sharma, Rakesh K.; Allamaneni, Shyam S. R.; Agarwal, Ashok
Fonte: Universidade de São Paulo. Faculdade de Medicina Publicador: Universidade de São Paulo. Faculdade de Medicina
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; Formato: application/pdf
Publicado em 01/08/2005 ENG
Relevância na Pesquisa
36.22%
OBJETIVO: Determinar se pacientes portadores do fator de infertilidade masculina podem ser precisamente identificados através do cálculo de um novo escore de qualidade de sêmen e pela medida de espécies reativas de oxigênio durante uma avaliação rotineira de infertilidade. MÉTODOS: Amostras de sêmen de 133 pacientes e de 91 doadores saudáveis foram avaliadas através de análise manual e computadorizada de sêmen. Um modelo de análise do componente principal foi empregado para calcular o escore de qualidade de sêmen, utilizando logaritmos base 10, multiplicados por ponderações variáveis de 9 parâmetros espermáticos. Os níveis de espécies reativas de oxigênio foram medidos através de testes de quimiluminescência. RESULTADOS: O escore de qualidade de sêmen apresentou sensibilidade de 80.45% e precisão de 77% para um "cutoff" de 93.1 na identificação do fator de infertilidade masculina. A área sob a curva "receiver operating characteristic" para o escore de qualidade de sêmen foi de 84.28% (95% intervalo de confiança: 65.22%-100%). Os níveis de espécies reativas de oxigênio [log10 (espécies reativas de oxigênio +1)] foram siginificativamente mais elevados nos pacientes portadores de fator de infertilidade masculina. A medica de espécies reativas de oxigênio apresentou sensibilidade de 83.47% e especificidade de 60.52% com uma precisão (definida como pacientes portadores do fator de infertilidade masculina com diagnóstico positivo e doadores corretamente excluídos) de 75% para um "cutoff" de 1.25 na identificação de pacientes portadores do fator de infertilidade masculina. A área sob a curva "receiver operating characteristic" para níveis de espécies reativas de oxigênio foi de 78.92% (95% intervalo de confiança: 72.60%-85.23%). Os escores de qualidade de sêmen correlacionaram negativamente com os níveis de espécies reativas de oxigênio tanto nos doadores e nos pacientes portadores do fator de infertilidade masculina. CONCLUSÕES: O escore de qualidade de sêmen e os níveis espécies reativas de oxigênio nas amostras de sêmen parecem associar-se fortemente com o fator de infertilidade masculina. Na medida em que os dois parâmetros mostraram-se mais sensíveis que parâmetros espermáticos individuais na identificação do fator de infertilidade masculina...

Operational sex ratio and density do not affect directional selection on male sexual ornaments and behavior

Head, Megan; Lindholm, Anna K.; Brooks, Rob
Fonte: Society for the Study of Evolution Publicador: Society for the Study of Evolution
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.28%
Demographic parameters including operational sex ratio (OSR) and population density may influence the opportunity for, and strength of sexual selection. Traditionally, male-biased OSRs and high population densities have been thought to increase the opportunity for sexual selection on male sexual traits due to increased male competition for mates. Recent experimental evidence, however, suggests that male-biased OSRs might reduce the opportunity for sexual selection due to increased sexual coercion experienced by females. How OSR, density, and any resultant changes in the opportunity for sexual selection actually affect selection on male sexual traits is unclear. In this study, we independently manipulated OSR and density in the guppy (Poecilia reticulata) without altering the number of males present. We recorded male and female behavior and used DNA microsatellite data to assign paternity to offspring and estimate male reproductive success. We then used linear selection analyses to examine the effects of OSR and density on directional sexual selection on male behavioral and morphological traits. We found that females were pursued more by males in male-biased treatments, despite no change in individual male behavior. There were no differences in sexual behavior experienced by females or performed by males in relation to density. Neither OSR nor density significantly altered the opportunity for sexual selection. Also...

Male competition is disruptive to courtship in the Pacific blue-eye

Wong, Bob
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.24%
The present study examined the effects of competition on male courtship in the Pacific blue-eye Pseudomugil signifer, a species of fish where females have previously been shown to use courtship, but not male fighting prowess, as an important mate choice cue. Courtship bouts directed to a stimulus female were shortest when two males were allowed to freely interact (contact treatment) and longest when there was only one male (non-interaction). Courtship length in trials where one of two males was confined to a clear cylinder (visual) was intermediate between the other two treatments. Courtship in visual and contact treatments was constantly disrupted. The percentage of interrupted courtships was higher for the contact compared to visual treatment where aggressive interactions were also longer in duration and took place more frequently. Within contact trials, dominant males courted longer than subordinates despite both males experiencing comparable rates of courtship disruption. These results suggest that male-male competition can have important implications for adaptive female choice particularly in circumstances where the benefits being sought by females are unrelated to male fighting ability.

Fighting success and attractiveness as predictors of male mating success in the black field cricket, Teleogryllus commodus : the effectiveness of no-choice tests

Shackleton, Michelle; Jennions, Michael; Hunt, John E
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.25%
Females are generally assumed to prefer larger, more dominant males. However, a growing number of studies that control for male-male competition have shown no correlation between dominance and attractiveness. Aggressive males can interfere with female mate preference either by physically coercing females into mating or by driving submissive males away and restricting mate choice. The most common method of assessing female mate choice is by using simultaneous two-choice tests. These control for male-male interactions, but usually interfere with physical and chemical cues involved in mate selection or alter male behaviour. They are therefore unsuitable for many study species, especially insects. Another method is the no-choice test that measures a female's latency to mating when placed with a single male as an indication of male attractiveness. No-choice tests control for male-male aggression while allowing full contact between pairs (they allow actual mating to be directly observed rather than to occur based on a correlated behaviour). So far, however, no study has confirmed that males that entice females to mate sooner actually enjoy increased longer-term mating success. As such, the accuracy of no-choice tests as a method of examining mate choice remains untested. Here...

Phenotypic, cytogenetic and spike fertility characterization of a population of male-sterile triticale

Guerra, Divanilde; Pacheco, Marcelo Teixeira; Federizzi, Luiz Carlos
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/02/2013 ENG
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Triticale (X Triticosecale Wittmack) is a good cereal for production of flour and feed. A segregating population of triticale was developed from a male-sterile (MS) plant. To determine whether this new source of male sterility in triticale is appropriate for use in breeding programs the expression of the male sterility phenotype was characterized through spike fertility, meiotic behavior, and pollen. Controlled crosses between male-sterile plants and control varieties male-fertile (MF) of triticale were also conducted, and cytological analyses were performed in the F2 and backcross plants. Plants with male-sterile phenotypes displayed reduced spike fertility when compared to plants with male-fertile phenotypes. Compared to male-fertile plants, male-sterile plants exhibited a lower percentage of normal meiotic cells, a reduced meiotic index and reduced pollen viability. The F2 plants had improved pollen fertility when compared to the male-sterile population; however there were no corresponding improvements in the percentage of normal meiotic cells or in the meiotic index. A single generation of backcrosses resulted in an improved meiotic index and increased pollen viability. However, no changes in the percentage of normal meiotic cells were observed. Meiotic instability...