Caracterização estrutural do fator de crescimento de fibroblasto-10 (FGF-10) e seu papel na fisiologia folicular ovariana

Background: Interest in folliculogenesis has grown extensively in recent years. Nevertheless, several aspects of follicular activity are still poorly understood. Thus, in vitro culture of ovarian follicles using new substances has been established as a very viable model, enhancing the prospects for a better understanding of follicular activity. Among the family members of the fibroblast growth factor (FGFs), FGF-10 has received recent attention for its ability to regulate the development of ovarian follicles and oocyte maturation. Given the relevance of FGF-10 in the folliculogenesis process, this review aimed to describe the structural features, expression and the main biological effects of FGF-10 on the development of ovarian follicles in mammals.Review: Along this work, it was shown aspects related to structural characterization of FGF-10 and its receptors, as well as FGF-10 expression in different cell types, emphasizing its importance to follicular development. FGF-10 is a paracrine member of the family of FGFs, and is characterized by promoting biological responses via cell surface receptors (FGFRs) of tyrosine kinase-type. of these receptors, FGFR-1, FGFR-2 and FGFR-3 may undergo alternative transcriptional arrangements, enabling the formation of two isoforms (b and c) that have varying degrees of affinity for the various FGFs. Thus, seven FGFR proteins (FGFRs 1b, 1c, 2b, 2c, 3b, 3c and 4) with different binding specificities are generated from the four FGFR genes. The FGFRs transmit intracellular signals after binding with the ligand through the phosphorylation of tyrosine, which activates various transduction patterns in the cytoplasm. The signal transduction of FGF-10 may occur through three main pathways: protein of rat sarcoma (Ras)/MAPK, PLC gamma/Ca(2+) and phosphatidylinositol-3 kinase (PI3K)/protein kinase B (Akt), which are involved in the transmission of biological signals, leading to cellular proliferation and differentiation. FGF-10 mRNA expression was detected in the ovarian stroma, oocyte and theca cells of preantral and antral follicles. on the other hand, the expression of mRNA for FGF-10 receptors was found in, granulosa cells, theca cells, cumulus cells and oocytes. Although FGFs are widely distributed in different tissues and cell types, the importance and function of FGFs in the ovary are still poorly documented. FGF-10 has been shown to be an important mediator of mesenchymal and epithelial cell interactions during follicle development, promoting follicular survival, activation and growth. Besides the action on folliculogenesis, FGF-10 was recently identified as a growth factor able to improve oocyte competence. However, in antral follicles, the presence of FGF-10 is associated with increased follicular atresia, which matches its anti-estrogenic action.Discussion: From this review, we can conclude that FGF-10 is an important regulator of female reproduction. This growth factor acts in follicle survival, oocyte maturation, expansion of cumulus cells and proliferation of granulosa/theca cellsthrough direct and/or indirect actions in the control of folliculogenesis. Furthermore, FGF-10 seemed to have different effects throughout the follicular development. However, it is necessary to perform additional studies that may provide a better understanding about the importance of FGF-10 during folicullogenesis.

Fibroblast growth factor-10 maintains the survival and promotes the growth of cultured goat preantral follicles

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The fibroblast growth factor family: involvement in the regulation of folliculogenesis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Germ line Cysts and the Formation of the Germinal Epithelium During the Female Gonadal Morphogenesis in Cyprinus Carpio (Teleostei: Ostariophysi: Cypriniformes)

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

Reproductive development and function of female rats exposed to di-eta-butyl-phthalate (DBP) in utero and during lactation

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

Reproductive pattern of the South American endemic shrimp Artemesia longinaris (Decapoda : Penaeoidea), off São Paulo State, Brazil

Sexual maturity, temporal reproductive pattern, and recruitment of juveniles were examined for the penaeoid shrimp Artemesia longinaris sampled for five and a half years in a tropical locality off the coast of São Paulo (23 degrees S), Brazil. Monthly samples were taken from January 1998 to June 2003 at depths between 5 and 45 m. Ovarian maturity was used to examine breeding in adult females. Recruitment was defined as the percentage of juveniles of the total number of individuals in each month and season. A total of 10 288 females and 5 551 males were collected. Estimated sizes (carapace length) at the onset of sexual maturity were 11.0 mm and 13.4 mm for males and females, respectively. Over the five and a half years, females with ripe gonads were found in every season, with the highest percentages in summer (January-March). Juvenile shrimps occur-red year-round. These results suggest a continuous reproduction of A. longinaris with temperature acting as an environmental stimulus for the duration of the ovary development cycle. These data and the hypothesis of the intrusion of the South Atlantic Central Water mass, which lowered water temperature and raised plankton production, suggest that the end of spring and the beginning of summer were the principal reproductive months. The classical paradigm of continuous reproduction at lower latitudes, with increased seasonality of breeding period at higher latitudes seems to apply to this species.

Reproduction and recruitment of the South American red shrimp, Pleoticus muelleri (Crustacea : Solenoceridae), from the Southeastern coast of Brazil

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

Reproductive cycle and ovarian development of the marine ornamental shrimp Stenopus hispidus in captivity

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Morphology, ultramorphology and histology of ovaries of workers and mated queens of Pachycondyla striata ants (Hymenoptera : Ponerinae)

The aim of the present work is to perform morphological and histological studies of the ovaries of workers and mated queens of Pachycondyla striata ants, which belong to the subfamily Ponerinae. The ovaries, after being removed, were schematized. Next, historesin and electronic scanning microscopy techniques were applied, making it possible to note that the left ovary owns a greater number of ovarioles when compared to the right one (workers - 7 to the right and 8 to the left; queens - 6 to the right and 7 to the left) and that the ovarioles of workers present a rather wrinkled aspect due to the fact that they are not developed. The same situation does not occur in mated queens once they always present oocytes in distinct development phases in their ovarioles. Histologically it was observed that the ovarioles are of the meroistic polytrophic kind. Inside the ovarioles of workers, germinative cells were observed in their distal portion, but their lumen were empty. on the other hand, ovarioles of mated queens presented the germinative cells as well as oocytes in different degrees of development, although more than one developing oocyte was never observed in the interior of each ovariole. It was possible to note the presence of follicular epithelium, chorion and vitellin membrane in oocytes of mated queens, which change morphologically according the oocyte development stage.

Female reproductive system of the decapitating fly Pseudacteon wasmanni Schmitz (Diptera : Phoridae)

Pseudacteon wasmanni is a South American decapitating fly that parasitizes workers of Solenopsis fire ants. We used light microscopy (historesin serial-sectioning stained with Haematoxylin/Eosin) and scanning electron microscopy to show and analyze internal and whole external views of the female reproductive system. All specimens analyzed (n = 9) by light microscopy showed post-vitellogenic oocytes inside the ovaries. The lack of typical follicles (oocyte-nurse cell complexes) in all specimens suggests that oogenesis occurs during the pupal stage. The total number of eggs found ranged from 31 to 280 (X = 142 +/- 73, SD). The egg has a slugform or torpedo shape (about 130 by 20 mum) with a pointed apex at the posterior pole as defined by the fly; the micropyle appears to be in a depression or invagination at the anterior pole. An acute hypodermic-like ovipositor is evaginated from the hard sclerotized external genitalia during egg laying. The existence of a muscular bulb associated with the end of the common oviduct suggests that the egg is injected into the ant's body by a strong contraction of the bulb which probably is stimulated by bending of several ventral sensilla. During contraction, the abdomen extends out along a large fold between the sixth and seventh tergites in such a way that the sclerotized genitalia is rotated ventrally into a slightly anterior orientation in preparation for oviposition. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

Effect of narcosis with CO2 on the ovarian development in queens of Apis mellifera (Hymenoptera, Apini)

Exposure of 1, 4, 7 & 10 day-old virgin queens of Apis mellifera Linne 1758 for 1 min to CO2 accelerated their ovarian development, having a similar effect as mating on the initial formation of the ovarian follicles. In 3 day-old queens the exposure to CO2 enhanced the initial stage of germ cell differentiation into oocytes and nurse cells in the ovarioles, a developmental stage only seen in 5 day-old untreated virgin queens, the age at which they are ready to mate. In 10 day-old untreated virgin queens, some regions of the ovarioles presented tissue disorganization and many cells with pycnotic nuclei. However, narcotized virgin queens of the same age did not present such ovary degeneration. Conversely, they showed nitid follicle formation, arising in the ovarioles' initial differentiation between nurse and oocytic chambers, although still without vitellogenesis. The accelerative effect of CO2 is limited to the ages near to those proper for mating, since 15 and 18 day-old treated virgin queens presented ovaries with extensive regions of high tissue disorganization and a great number of cells with pycnotic nuclei. According to the results, the narcosis presented three levels of effect on the ovary of honeybee virgin queens: 1) accelerated the germ cell differentiation, 2) preserved the tissue integrity even after the queen mating period and 3) stimulated the initial differentiation of a vitellarium. This later condition was only seen in untreated queens after mating. All these effects are not maintained if the queen is kept virgin beyond 15 days old.

Amblyomma triste (Koch, 1844) (Acari : Ixodidae) Ovaries: An ultrastructural analysis

This study presents an ultrastructural analysis of the ovary of the tick, Amblyomma triste. The ovary of this species is of the panoistic type that is, without nursing and follicular cells. It is composed of a layer of epithelial cells forming a wall and of germinative cells that generate the oocytes which remain attached to the external margin of this wall by a multicellular pedicel. The different developmental stages in the oocytes had been described by Oliveira et al. [Oliveira, P.R., Bechara, G.H., Camargo-Mathias, M.I., 2006. Amblyomma triste (Koch, 1844) (Acari: Ixodidae): Morphological description of the ovary and of vitellogenesis. Experimental Parasitology 113, 179-185]. The results of the investigation suggest that besides exogenous production of vitellogenic elements, endogenous production can take place simultaneously, contributing to the development and growth of the oocytes. (c) 2007 Elsevier B.V. All rights reserved.

Ultrastructural detection of proteins, lipids and carbohydrates in oocytes of Amblyomma triste (Koch, 1844) (Acari; Ixodidae) during the vitellogenesis process

The ovary of the tick Ainblyomma triste is classified as panoistic, which is characterized by the presence of oogonia without nurse and follicular cells. The present study has demonstrated that the oocytes in all developmental stages (I-IV) are attached to the ovary through a pedicel, a cellular structure that synthesizes and provides carbohydrate, lipids and proteins supplies for the oocytes during the vitellogenesis process. The lipids are deposited during all oocyte stages; they are freely distributed as observed in stages II, III and IV or they form complexes with other elements. The proteins are also deposited in all stages of the oocytes, however, in lower concentration in the stage IV. There is carbohydrate deposition from oocytes in the stage II as well as in stages III and IV. In addition, the present work has demonstrated that the oocyte yolk of A. triste has a glycolipoprotein nature and the elements are deposited in the following sequence: firstly the lipids and proteins, and finally the carbohydrates. (c) 2007 Elsevier Ltd. All rights reserved.

Secretory cycle of the Dufour's gland in workers of the bumble bee Bombus terrestris L-(Hymenoptera : Apidae, Bombini)

The Dufour's gland of Bombus terrestris workers, of different ages and with varying degrees of ovary development, was studied with the aim to verify its involvement in reproduction. Measurements of the diameter and the length of the gland were made using an ocular micrometer adapted to a microscope. Transmission electron microscopy was used to study the morphology of the secretory cells and to analyze the secretory cycle. The glandular cells were considered to be near type II cells of NOIROT and QUENNEDEY (1974), a type that has not been described before in Hymenopterans. The results show that there is a correlation between the degree of ovary development and Dufour's gland activity of workers. The diameter of the gland and the secretory cell activity increased with increasing oocyte size in the ovary. Regressive conditions of the gland were observed, which are probably related to increasing worker age. To elucidate the production and releasing process of the secretion and to establish its precise function, a comparative analysis of the secretion process of the Dufour's gland of queens and workers is needed.

Vitellogenesis in the tick Amblyomma triste (Koch, 1844) (Acari : Ixodidae) - Role for pedicel cells

This study presents new information on the vitellogenesis of the tick Amblyomma triste. In this species, the ovary consists of a layer of epithelial cells, which form the ovarian wall, oogonia and developing oocytes; and the pedicel, a cellular structure that synthesizes and provides yolk precursors for developing oocytes. The pedicel also attaches oocytes to the external surface of the epithelial wall. In this study, evidence is provided in support of pedicel cells in providing compounds for oocytes during vitellogenesis. (c) 2006 Elsevier B.V. All rights reserved.