22 resultados para Male genitalia


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There is a gap in terms of the supposed survival differences recorded in the field according to individual condition. This is partly due to our inability to assess survival in the wild. Here we applied modern statistical techniques to field-gathered data in two damselfly species whose males practice alternative reproductive tactics (ARTs) and whose indicators of condition in both sexes are known. In Paraphlebia zoe, there are two ART: a larger black-winged (BW) male which defends mating territories and a smaller hyaline-winged (HW) male that usually acts as a satellite. In this species, condition in both morphs is correlated with body size. In Calopteryx haemorrhoidalis, males follow tactics according to their condition with males in better condition practicing a territorial ART. In addition, in this species, condition correlates positively with wing pigmentation in both sexes. Our prediction for both species was that males practicing the territorial tactic will survive less longer than males using a nonterritorial tactic, and larger or more pigmented animals will survive for longer. In P. zoe, BW males survived less than females but did not differ from HW males, and not necessarily larger individuals survived for longer. In fact, size affected survival but only when group identity was analysed, showing a positive relationship in females and a slightly negative relationship in both male morphs. For C. haemorrhoidalis, survival was larger for more pigmented males and females, but size was not a good survival predictor. Our results partially confirm assumptions based on the maintenance of ARTs. Our results also indicate that female pigmentation, correlates with a fitness component - survival - as proposed by recent sexual selection ideas applied to females.

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Structure of inflorescences and flowers and flowering behaviour are reported for the woody liana Anchietea pyrifolia (Violaceae) from Brazil. The specimen studied is grown for some decades now in the greenhouses of Halle Botanical Garden and turned out unisexually male, which adds a further example of dioecism to the family Violaceae, in which this type of sex distribution is rarely encountered. The flowers are exceptional also for the strongly asymmetric anterior petal, which represents a rare case of a species with enantiomorphic flowers pollinated by Lepidoptera. They have a fully developed gynoecium with a complicated architecture comparable to the pistil of bisexual Violaceae flowers, though without ovules. The style head is capable to release viscose liquid on tactile stimulation or pressure, which is known to act as pollen-gathering mechanism in bisexual Violaceae species with usually dry pollen and buzz-pollination. This function has switched in male A. pyrifolia to a mechanism for efficient pollen release mediated by insect pollinators from its short-lived flowers. (C) 2009 Elsevier GmbH. All rights reserved.

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Although radiotelemetry is considered a valuable technique for ornithological field studies, several assumptions have been made about the impact that transmitters may have on the estimation of behavioral, ecological, and reproductive parameters. To assess the potential effects of backpack radiotransmitters, we captured and assigned 8 male American kestrels (Falco sparverius) into 2 groups: radiotagged (n = 6) and control individuals (leg-banded, n = 2). Thereafter, we collected feces approximately 2 hours after capture (day -1), and subsequently during days 0 (releasing day), 4, 7, 15, 30, 40, and 55. Prior to fecal analysis, we validated the corticosterone enzyme immunoassay using standard procedures (e. g., parallelism, dose-response curve), and we confirmed physiological significance of fecal glucocorticoid metabolites through adrenocorticotropin challenge, which induced an increase of 4-fold (446.10 +/- 60.73 ng/g) above baseline (114.27 +/- 15.23 ng/g) within 4 hours (P < 0.001). Both groups exhibited a significant increase in fecal glucocorticoids during day 0 (P < 0.001), but concentrations returned to preattachment values within 4 days. Fecal glucocorticoid concentrations did not differ between samples of radiotagged and leg-banded kestrels (P > 0.05). In spite of the small number of monitored subjects, these findings suggested that radiotransmitters did not affect adrenocortical activity in these male American kestrels. (JOURNAL OF WILDLIFE MANAGEMENT 73(5): 772-778; 2009)

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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, and virtually no colocalization with Fos was observed. We found intense NADPHd activity in PMV neurons, some of which coexpressed Fos-ir after exposure to both odors. The majority of the PMV neurons expressing NADPHd colocalized cocaine-and amphetamine-regulated transcript (CART). Our findings suggest that female and male odors engage distinct neuronal populations in the MEA, thereby inducing contextualized behavioral responses according to olfactory cues. In the PMV, NADPHd/CART neurons respond to male and female odors, suggesting a role in neuroendocrine regulation in response to olfactory cues. (C) 2009 Elsevier Inc. All rights reserved.

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To date, there has been only one in vitro study of the relationship between neuropeptide EI (NEI) and the hypothalamic-pituitary-thyroid (HPT) axis. To investigate the possible relationship between NEI and the HPT axis, we developed a rat model of hypothyroidism and hyperthyroidism that allows us to determine whether NEI content is altered in selected brain areas after treatment, as well as whether such alterations are related to the time of day. Hypothyroidism and hyperthyroidism, induced in male rats, with 6-propyl-1-thiouracil and L-thyroxine, respectively, were confirmed by determination of triiodothyronine, total thyroxine, and thyrotropin levels. All groups were studied at the morning and the afternoon. In rats with hypothyroidism, NEI concentration, evaluated on postinduction days 7 and 24, was unchanged or slightly elevated on day 7 but was decreased on day 24. In rats with hyperthyroidism, NEI content, which was evaluated after 4 days of L-thyroxine administration, was slightly elevated, principally in the preoptic area in the morning and in the median eminence-arcuate nucleus and pineal gland in the afternoon, the morning and afternoon NEI contents being similar in the controls. These results provide the bases to pursue the study of the interaction between NEI and the HPT axis. (C) 2011 Elsevier Inc. All rights reserved.

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Nandrolone is an anabolic-androgenic steroid (AAS) that is highly abused by individuals seeking enhanced physical strength or body appearance. Supraphysiological doses of this synthetic testosterone derivative have been associated with many physical and psychiatric adverse effects, particularly episodes of impulsiveness and overt aggressive behavior. As the neural mechanisms underlying AAS-induced behavioral disinhibition are unknown, we investigated the status of serotonergic system-related transcripts in several brain areas of mice receiving prolonged nandrolone administration. Male C57BL/6J mice received 15 mg/kg of nandrolone decanoate subcutaneously once daily for 28 days, and different sets of animals were used to investigate motor-related and emotion-related behaviors or 5-HT-related messenger RNA (mRNA) levels by real-time quantitative polymerase chain reaction. AAS-injected mice had increased body weight, were more active and displayed anxious-like behaviors in novel environments. They exhibited reduced immobility in the forced swim test, a higher probability of being aggressive and more readily attacked opponents. AAS treatment substantially reduced mRNA levels of most investigated postsynaptic 5-HT receptors in the amygdala and prefrontal cortex. Interestingly, the 5-HT(1B) mRNA level was further reduced in the hippocampus and hypothalamus. There was no alteration of 5-HT system transcript levels in the midbrain. In conclusion, high doses of AAS nandrolone in male mice recapitulate the behavioral disinhibition observed in abusers. Furthermore, these high doses downregulate 5-HT receptor mRNA levels in the amygdala and prefrontal cortex. Our combined findings suggest these areas as critical sites for AAS-induced effects and a possible role for the 5-HT(1B) receptor in the observed behavioral disinhibition.

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Human papillomavirus is a DNA virus that includes 118 genotypes. HPV16 is responsible for 80% of cervical cancer in women. Men are important reservoirs and major transmitters of HPV to their partners. The aim of this study was to detect HPV DNA and to determine the prevalence of HPV types 6, 11, 16, and 18 in urine samples of men infected with HIV-1. This study included 223 patients infected with HIV-1 from the Center of Reference on HIV/AIDS (CRT-SP) and an outpatient clinic of HIV. Urine samples were collected and after DNA extraction real-time PCR was performed for detection of HPV DNA. Positive samples were then tested by conventional PCR using type-specific primers for the four HPV types. A total of 223 men infected with HIV-1 were tested, 81% of whom were on HAART. Four (5.8%) were positive for HPV6, 18 (26.1%) were positive for HPV11, 22 (31.9%) were positive for HPV16 and five (7.2%) were positive for HPV18 by conventional PCR. Twenty (29%) patients had other HPV types and five patients (1.5%) had multiple types. The mean T CD4+cells count was 517 and 441 cells/mm(3) (P=0.30), in HPV negative and positive men, respectively. The HIV viral load was higher in the HPV negative group than for in the men with HPV (P=0.0002). A 30.9% prevalence of HPV was found in asymptomatic urine samples of men infected with HIV-1. This study suggests that urine may be a useful specimen for HPV screening. J. Med. Virol 81:2007-2011, 2009. (C) 2009 Wiley-Liss, Inc.