Regulation of male sexual development by Sry and Sox9

Sry, a gene from the Y chromosome, is known to initiate testis formation and subsequent male differentiation in mammals. A related gene, Sox9, also plays a critical role in testis determination, possibly in all vertebrates. A number of models have been presented regarding the molecular modes of action of these two genes. However, details regarding their regulation, regulatory target genes, and interacting protein factors and co-factors have not been established with any certainty. In this review, we examine new evidence and re-examine existing evidence bearing on these issues, in an effort to build up an integrative model of the network of gene activity centred around Sry and Sox9. J. Exp. Zool. 290:463-474, 2001. (C) 2001 Wiley-Liss, Inc.

Molecular mechanisms of sexual development in basidiomycetes: exploring connections with lifestyles

Dissertação para obtenção do Grau de Doutor em Biologia

Reproductive physiology, and physical and sexual development of female offspring born to diabetic dams

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sexual development and reproductive cycle of the Eyespot skate Atlantoraja cyclophora (Regan, 1903) (Chondrichthyes: Rajidae: Arhynchobatinae), in southeastern Brazil

Specimens o/Atlantoraja cyclophora were collected monthly from commercial fishing landings at Guarujá, São Paulo State, Brazil, from March 2005 to April 2006 at depths between 10 and 146 m. Males ranged from 13.3 to 58.5 cm TL (n = 396). Both the smallest mature male and the largest immature male were 47.0 cm long. Males' size-at-50% maturity was calculated to be 46.3 cm. Females ranged from 11.5 to 68.0 cm (n = 401). The smallest mature and the largest immature female were 51.6 and 53.0 cm long respectively. For the females, size-at-50% maturity was calculated to be 53.2 cm. In the males the hepatosomatic andgonadosomatic indices varied between 0.48 (August) and 3.54 (November) and between 0.15 (November) and 1.45 (June) respectively, with no significant variation for the fourteen-month period. In the females the hepatosomatic and gonadosomatic indices varied from 1.55 and 6.30 3.54 (both for April 2006) and from 0.08 (December) to 4.41 (October) respectively, with no significant difference among months. Egg-bearing females were found in all months with proportions varying from 0.03 (March) to 0.67 (April). Both males and females undergo an annual cycle, with slight seasonal variations in reproductive activity and a peak in the proportion of egg bearing females between April and July.

Sexual development, size at maturity, size at maternity and fecundity of the blue shark Prionace glauca (Linnaeus, 1758) in the Southwest Atlantic

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Reproductive physiology, and physical and sexual development of female offspring born to diabetic dams

Objectives: The objective of this study was to evaluate physical and sexual development and reproductive physiology in female rat offspring that developed in hyperglycemia conditions in utero and during lactation. Materials and methods: Maternal diabetes was induced in female rats by a single IV injection of streptozotocin before mating. Female offspring development was evaluated by means of the following parameters: physical development; age of vaginal opening and first estrus; weight and histological evaluation of uterus and ovaries; duration of the estrous cycle, sexual behavior, and fertility after natural mating. Results: In the female offspring, maternal diabetes caused delays in initial physical development; diminution in ovary weight and number of follicles; and inferior reproductive performance compared with the control group. Conclusions: The exposure to hyperglycemia in uterus and during lactation caused delays in physical and sexual development, and affected the reproductive physiology of female rats negatively.

Mounting behaviour in finishing pigs: Stable individual differences are not due to dominance or stage of sexual development

Every year around 100 million male piglets are castrated in the EU, usually without anaesthesia or post-operative analgesia. This surgical intervention is painful and stressful. Several main players within the pig industry have voluntarily agreed to end the practice of surgical pig castration in the EU by 2018. One alternative to castration is entire male pig production. However, entire males behave differently than castrates, for example, by performing more mounting behaviour, which is suggested to be a welfare problem. The aim of our study was to develop a comprehensive ethogram of different types of mounting and to investigate properties, causes and consequences of mounting behaviour in finishing pigs. The study included 80 entire male and 80 female pigs from two farrowing batches born six weeks apart. Mixed sex and single-sex housing of pigs are both common in pig farming, so to ensure our study was representative, the 160 pigs were assigned to social groups of 20 in three treatments: entire male pigs only (MM, 2 groups, n = 40), entire females only (FF, 2 groups, n = 40) and entire males and females mixed together (MF, 4 groups, n = 80). Measurements took place during the final six weeks before slaughter (between 63.5 and 105.5 kg). Observations of mounting behaviour on 12 days per batch suggested that: (i) males mounted more than females, (ii) within sex, there was no effect of treatment on the amount of mounting (although the statistical power of the study to detect these effects was low), and (iii) there were individual differences in mounting that were stable over time (within sex). Classification of mounting into different categories revealed that sexual mounting was most common overall and in males but only rare in females. Compared to other types of mounting (e.g. caused by crowding or during a fight), sexual mounts lasted longer and provoked more screaming by the recipient. There were no relationships between mounting behaviour on the one hand and dominance rank in food competition tests, the circulating levels of sex hormones (oestradiol, testosterone and progesterone) at the end of the study, the health scores (lameness and scratches) or weight gain on the other hand. The stable individual differences of mounting over time suggest that mounting behaviour is a trait of the individual rather than the appearance of random outbreaks. However, these differences in mounting cannot be explained by dominance behaviour or by differences in sex hormone concentrations that could indicate the onset of puberty. Mounting behaviour and in particular sexual mounting provoked high pitched screaming of the recipients indicating that mounting is a welfare problem. For the welfare assessment of entire male pig production the performance of mounting behaviour should be considered. (C) 2013 Elsevier B.V. All rights reserved.

The makings of maleness: towards an integrated view of male sexual development

As the mammalian embryo develops, it must engage one of the two distinct programmes of gene activity, morphogenesis and organogenesis that characterize males and females. In males, sexual development hinges on testis determination and differentiation, but also involves many coordinated transcriptional, signalling and endocrine networks that underpin the masculinization of other organs and tissues, including the brain. Here we bring together current knowledge about these networks, identify gaps in the overall picture, and highlight the known defects that lead to disorders of male sexual development.

Origin and possible roles of the Sox8 transcription factor gene during sexual development

Sox8 is a member of the Sox family of developmental transcription factor genes and is closely related to Sox9, a critical gene involved in mammalian sex determination and differentiation. Both genes encode proteins with the ability to bind similar DNA target sequences, and to activate transcription in in vitro assays. Expression studies indicate that the two genes have largely overlapping patterns of activity during mammalian embryonic development. A knockout of Sox8 in mice has no obvious developmental phenotype, suggesting that the two genes are able to act redundantly in a variety of developmental contexts. In particular, both genes are expressed in the developing Sertoli cell lineage of the developing testes in mice, and both proteins are able to activate transcription of the gene encoding anti-Mullerian hormone (AMH), through synergistic action with steroidogenic factor I (SF1). We have hypothesized that Sox8 may substitute for Sox9 in species where Sox9 is expressed too late to be involved in sex determination or regulation of Amh expression. However, our studies involving the red-eared slider turtle indicate that Sox8 is expressed at similar levels in males and females throughout the sex-determining period, suggesting that Sox8 is neither a transcriptional regulator for Amh, nor responsible for sex determination or gonad differentiation in that species. Similarly, Sox8 is not expressed in a sexually dimorphic pattern during gonadogenesis in the chicken. Since a functional role(s) for Sox8 is implied by its conservation during evolution, the significance of Sox8 for sexual and other aspects of development will need to be uncovered through more directed lines of experimentation. Copyright (C) 2003 S. Karger AG, Basel.

Sex Determination and Female Reproductive Development in the Genus Schistosoma: A Review

Parasites of the genus Schistosoma were among the first metazoans to develop separate sexes, which is chromosomally determined in the fertilized egg. Despite the occurrence of specific sex chromosomes, the females of most Schistosomatidae species do not complete their somatic development and reach no sexual maturity without the presence of males. Indeed, the most controversial and at the same time most fascinating aspect about the sexual development of Schistosoma females lies on discover the nature of the stimulus produced by males that triggers and controls this process. Although the nature of the stimulus (physical or chemical) is a source of controversy, there is agreement that mating is a necessary requirement for maturation to occur and for migration of the female to a definitive final site of residence in the vascular system of the vertebrate host. It has also been proposed that the stimulus is not species-specific and, in some cases, not even genus-specific. Despite a vast literature on the subject, the process or processes underlying the meeting of males and females in the circulatory system have not been determined and as yet no consensus exists about the nature of the stimulus that triggers and maintains female development. In the studies about their role, Schistosoma males have been considered, at times pejoratively, the brother, the muscles or even the liver of females. Indeed, it still remains to be determined whether the stimulus responsible for female maturation involves the transfer of hormones, nutrients, neuromediators, mere tactile stimulation or a combination of chemotactic and thigmotactic factors

The genome and development-dependent transcriptomes of Pyronema confluens: a window into fungal evolution

Fungi are a large group of eukaryotes found in nearly all ecosystems. More than 250 fungal genomes have already been sequenced, greatly improving our understanding of fungal evolution, physiology, and development. However, for the Pezizomycetes, an early-diverging lineage of filamentous ascomycetes, there is so far only one genome available, namely that of the black truffle, Tuber melanosporum, a mycorrhizal species with unusual subterranean fruiting bodies. To help close the sequence gap among basal filamentous ascomycetes, and to allow conclusions about the evolution of fungal development, we sequenced the genome and assayed transcriptomes during development of Pyronema confluens, a saprobic Pezizomycete with a typical apothecium as fruiting body. With a size of 50 Mb and ~13,400 protein-coding genes, the genome is more characteristic of higher filamentous ascomycetes than the large, repeat-rich truffle genome; however, some typical features are different in the P. confluens lineage, e.g. the genomic environment of the mating type genes that is conserved in higher filamentous ascomycetes, but only partly conserved in P. confluens. On the other hand, P. confluens has a full complement of fungal photoreceptors, and expression studies indicate that light perception might be similar to distantly related ascomycetes and, thus, represent a basic feature of filamentous ascomycetes. Analysis of spliced RNA-seq sequence reads allowed the detection of natural antisense transcripts for 281 genes. The P. confluens genome contains an unusually high number of predicted orphan genes, many of which are upregulated during sexual development, consistent with the idea of rapid evolution of sex-associated genes. Comparative transcriptomics identified the transcription factor gene pro44 that is upregulated during development in P. confluens and the Sordariomycete Sordaria macrospora. The P. confluens pro44 gene (PCON_06721) was used to complement the S. macrospora pro44 deletion mutant, showing functional conservation of this developmental regulator.

Changes in light intensity can influence age at sexual maturity in domestic pullets

1. Shaver White and ISA Brown pullets were reared to 140 d in groups of 8 in cages on a 10-h photoperiod of incandescent light and maintained at an illuminance of 3 or 25 lux, or transferred from 3 to 25 lux or from 25 to 3 lux at 63 or 112 d of age. 2. There was no significant difference in sexual maturity, measured as eggs per 100 bird.d at 139 and 140 d, for ISA Brown maintained on 3 or 25 lux, but Shaver White pullets exposed to constant 3 lux matured significantly later than those maintained on 25 lux. 3. In Shaver Whites, sexual maturity was significantly delayed by an increase from 3 to 25 lux at 63 and 112 d, and advanced by a decrease from 25 to 3 lux at 112 d. Sexual maturity of ISA Browns was not significantly affected by a change in illuminance at 63 or 112 d, though responses were in the same direction as for Shaver Whites. 4. In both breeds, total feed consumed to 112 d was higher for birds on 3 lux than 25 lux, but lower between 112 d and 140 d when birds on 25 lux underwent rapid sexual development. In both breeds, body weight at 63 d was higher for birds exposed to 3 lux than 25 lux, but body weight gain thereafter was similar for the two light intensities. 5. In both breeds, plasma luteinising hormone (LH) concentration at 63 and 112 d was lower in birds maintained on 3 lux than 25 lux. At 63 and 112 d, transfers from 25 to 3 lux depressed, whereas transfers from 3 to 25 lux at 63 d, but not at 112 d, increased plasma LH. 6. Advances or delays in sexual maturity induced by changes in illuminance were not correlated with differences in feed intake, body weight gain, or with changes in plasma LH. 7. One possible explanation for the inverse relationship between the direction of change in illuminance at 63 and 112 d in pullets exposed to a 10-h photoperiod and the age at which they became sexually mature is that changes in light intensity and/or spectral composition affect the entrainment of the circadian rhythm of photoinducibility, to effect a phase shift in the photoinducible phase and/or the responsiveness of phototransduction pathways.

Interação sexual: perspectiva etológica do dimorfismo sexual humano

A interação sexual no sentido de ação conjunta ou recíproca supõe a existência de parceiros dimorficamente caracterizados a partir da estrutura cromossomial X-X ou X-Y. A diferenciação do sexo, entretanto, não depende apenas da condição cromossomial, podendo mesmo ser invertida quando a ação hormonal for alterada. Os dados disponíveis apontam os andrógenos como um dos principais agentes de diferenciação, afetando o organismo "básico" feminino num sentido masculinizante. A medida que se progride na escala animal, contudo, os aspectos estritamente biológicos perdem em importância e as condições ambientais aos poucos se impõem . Nos primatas superiores, caso não se estabeleçam condições adequadas de aprendizagem, o desenvolvimento sexual não se completa e a cópula se torna inviável. No ser humano, além dessa aprendizagem, fatores socio-culturais respondem pelo comportamento considerado masculino ou feminino que supostamente será exibido por cada parceiro da interação. Também as noções de estética são seriamente determinadas pela tradição cultural, com cada povo tendendo a valorizar os próprios traços raciais como ideal de beleza. Do ponto de vista físico, entretanto, pode-se tentar estabelecer algumas constantes, como as formas arredondadas para a mulher e o porte atl6tico ou capacidades gerais , para o homem. Uma vez estabelecida a atração e encontrado local e momento adequado, a interação sexual tende a uma progressiva intensificação e genitalização, que, nas sociedades de tradição judaico-cristã se reflete numa sequência, mais ou menos previsível, envolvendo carícias gerais, beijos, acariciamento de seios e genitais até a união genito-genital o significado e a forma como cada cultura desenvolve os contatos físicos de intercambio erógeno revelam tão grande variedade que já se apontou essa polimorfismo corno aquisição típica do ser humano. Assim, ao contrário do que faz supor o ideal de abstinência, é na capacidade de buscar e estender o prazer além da s1mples atividade orgânico-sexual que o homem, em sexo, se liberta da limitação animal.