RESUMO
In insect societies, chemical communication plays an important role in colony reproduction and individual social status. Many studies have indicated that cuticular hydrocarbons (CHCs) are the main chemical compounds encoding reproductive status. However, these studies have largely focused on queenless or monogynous species whose workers are capable of egg laying and have mainly explored the mechanisms underlying queen-worker or worker-worker reproductive conflicts. Less is known about what occurs in highly polygynous ant species with permanently sterile workers. Here, we used the Argentine ant as a model to examine the role of CHCs in communicating reproductive information in such insect societies. The Argentine ant is unicolonial, highly polygynous, and polydomous. We identified several CHCs whose presence and levels were correlated with queen age, reproductive status, and fertility. Our results also provide new insights into queen executions in the Argentine ant, a distinctive feature displayed by this species in its introduced range. Each spring, just before new sexuals appear, workers eliminate up to 90% of the mated queens in their colonies. We discovered that queens that survived execution had different CHC profiles from queens present before and during execution. More specifically, levels of some CHCs were higher in the survivors, suggesting that workers could eliminate queens based on their chemical profiles. In addition, queen CHC profiles differed based on season and species range (native vs. introduced). Overall, the results of this study provide new evidence that CHCs serve as queen signals and do more than just regulate worker reproduction.
Assuntos
Estruturas Animais/metabolismo , Formigas/metabolismo , Hidrocarbonetos/metabolismo , Espécies Introduzidas , Estações do Ano , Animais , Feminino , Masculino , Reprodução/fisiologiaRESUMO
Male circumcision has been shown to reduce the risk of acquiring and transmitting a number of venereal infections. However, little is known about the association between male circumcision and the risk of Chlamydia trachomatis infection in the female partner. The authors pooled data on 305 adult couples enrolled as controls in one of five case-control studies of invasive cervical cancer conducted in Thailand, the Philippines, Brazil, Colombia, and Spain between 1985 and 1997. Women provided blood samples for C. trachomatis and Chlamydia pneumoniae antibody detection; a type-specific microfluorescence assay was used. Multivariate odds ratios were computed for the association between male circumcision status and chlamydial seropositivity in women. Compared with women with uncircumcised partners, those with circumcised partners had a 5.6-fold reduced risk of testing seropositive for C. trachomatis (82% reduction; odds ratio = 0.18, 95% confidence interval: 0.05, 0.58). The inverse association was also observed after restricting the analysis to monogamous women and their only male partners (odds ratio = 0.21, 95% confidence interval: 0.06, 0.72). In contrast, seropositivity to C. pneumoniae, a non-sexually-transmitted infection, was not significantly related to circumcision status of the male partner. These findings suggest that male circumcision could reduce the risk of C. trachomatis infection in female sexual partners.
Assuntos
Infecções por Chlamydia/epidemiologia , Chlamydia trachomatis , Circuncisão Masculina , Parceiros Sexuais , Adulto , Brasil/epidemiologia , Colômbia/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Filipinas/epidemiologia , Medição de Risco , Estudos Soroepidemiológicos , Comportamento Sexual , Espanha/epidemiologia , Tailândia/epidemiologiaRESUMO
At least 15 types of HPV have been associated with cervical cancer, but current HPV vaccines confer only type-specific immunity. To determine geographic variations in the HPV type distribution in cervical cancer, we carried out a pooled analysis of data from an international survey of HPV types in cervical cancer and from a multicenter case-control study, both co-coordinated by the IARC. Study cases were 3,607 women with incident, histologically confirmed cervical cancer recruited in 25 countries. HPV DNA detection and typing in cervical cells or biopsies were centrally done using PCR assays. Estimates of the potential number of cases prevented by HPV type-specific vaccines and changes in the validity of different HPV screening cocktails were calculated. HPV DNA was detected in 96% of specimens, and 30 different types were detected. The 15 most common types were, in descending order of frequency, 16, 18, 45, 31, 33, 52, 58, 35, 59, 56, 39, 51, 73, 68 and 66. Higher than average proportions of type 16 were found in northern Africa, of type 18 in south Asia, of type 45 in sub-Saharan Africa and of type 31 in Central/South America. A vaccine including types 16 and 18 could potentially prevent 71% of cervical cancers worldwide, but its impact with regard to the percentage of cases potentially prevented would be higher in Asia and Europe/North America. In contrast, a vaccine containing the 7 most common HPV types would prevent about 87% of cervical cancers worldwide, with little regional variation. The impact of modifying the number of types in the screening cocktail tests would be small and probably irrelevant for screening programs.