Follicular diameter range based on morphological features in Synbranchus marmoratus (Bloch, 1795) (Teleostei, Synbranchiformes, Synbranchidae) from the South-central region of Brazil

The morphological characteristics of Synbranchus marmoratus female germ cells in various development stages were described in details; then measurements of ovarian follicle diameters were taken from primary and secondary growth as during these development stages the oocyte size varied considerably along the fish growth. The results were correlated to total fish length, using the individuals division in six size classes. It was possible to group oocytes by stages according to histological characteristics but not according to morphometric diameter, as there was a wide variation in diameter in each stage and overlap between different maturation stages. These data make available new information on the reproductive biology of Synbranchidae. (c) 2004 Published by Elsevier Ltd.

Follicular epithelium, theca and egg envelope formation in Serrasalmus spilopleura (Teleostei, Characiformes, Characidae)

The follicular epithelium and theca of oocytes in Serrasalmus spilopleura differentiates during the initial primary growth phase. The follicular cells are squamous and the thecal cells are disposed in two layers. During the secondary growth phase, follicular cells become cuboidal, acquire characteristics typical of protein- or glycoprotein-producing cells, and show dilated intercellular spaces. Formation of the egg envelope in S. spilopleura begins in the previtellogenic oocytes as a layer of amorphous electron-dense material is laid down on the oolemma. During vitellogenesis, another layer of electron-dense material appears beneath the first layer. Also during this phase, a layer of amorphous, less electron-dense material is formed adjacent to the follicular epithelium. The secondary egg envelope appears at the postvitellogenic phase and is composed of a filamentous and undulant material. The morphology of the egg envelopes in S. spilopleura reflects not only its oviparous nature but also the fact that its eggs are adhesive.

A new vision of the origin and the oocyte development in the Ostariophysi applied to Gymnotus sylvius (Teleostei: Gymnotiformes)

Tendo por base os novos conhecimentos oriundos de recentes estudos com Perciformes marinho, a origem e o desenvolvimento dos oócitos no Ostariophysi Gymnotus sylvius são aqui descritos. da mesma maneira que ocorre nos Perciformes, em Gymnotus sylvius as oogônias são encontradas no epitélio germinativo que margeia as lamelas ovígeras. No início da foliculogênese, a proliferação das oogônias e sua entrada em meiose dão origem a ninhos de células germinativas que se projetam em direção ao estroma ovariano, a partir do epitélio germinativo. Os ninhos e o epitélio germinativo são suportados pela mesma membrana basal que os separa do estroma. Coincidindo com a paralisação da meiose os oócitos, presentes nos ninhos, são separados uns dos outros por processos citoplasmáticos das células pré-foliculares. As células pré-foliculares derivam do epitélio germinativo sendo, portanto, inicialmente células epiteliais. Durante a foliculogênese, ao mesmo tempo em que envolvem os oócitos individualizando-os, as células pré-foliculares sintetizam a membrana basal ao seu redor. Os oócitos entram em crescimento primário ainda dentro dos ninhos. Ao término da foliculogênese, o oócito e as células foliculares que compõem o folículo são circundados pela membrana basal. O folículo permanece conectado ao epitélio germinativo uma vez que ambos compartilham uma porção comum da membrana basal. Células oriundas do estroma circundam o folículo ovariano exceto na região de compartilhamento da membrana basal formando a teca. O folículo, a membrana basal e a teca formam o complexo folicular. O desenvolvimento do oócito ocorre dentro do complexo folicular e compreende os estágios de crescimento primário e secundário, maturação e ovulação. Os alvéolos corticais surgem no ooplasma momentos antes do início do crescimento secundário ou estágio vitelogênico que tem início com a deposição de vitelo, progride até o oócito esteja completamente desenvolvido e o ooplasma preenchido pelos glóbulos de vitelo. A maturação é caracterizada pela migração do núcleo ou vesícula germinativa, pela quebra da vesícula germinativa, ou seja, pela fragmentação do envoltório nuclear e, retomada da meiose. Na ovulação o ovo é liberado do complexo folicular para o lúmen ovariano. em comparação com os Perciformes marinhos com ovos pelágicos, o desenvolvimento oocitário em Gymnotus sylvius tem menos etapas dentro dos estágios de desenvolvimento, sendo as duas mais notáveis delas as ausências da formação das gotas de lipídio durante os crescimentos primário e secundário (e a consequente fusão das gotas para formar um único glóbulo de lipídio durante a maturação) e, a hidrólise do vitelo antecedendo a ovulação.

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)

Reprodução em cativeiro do jurupecê Sorubim lima (Siluriformes, Pimelodidae) por meio de indução hormonal

Sorubim lima is a migratory catfish that do not reproduce in lenthic environments such as those formed after construction of hydroelectric power plants. An alternative for conservation of the species in these environments is the stocking with fingerlings produced in captivity. The technique used to reproduce it in captivity was the induction by carp pituitary hormone, with dosage of 5 mg.kg(-1) for females (1 mg.kg(-1) in the first dose and 4 mg.kg(-1) in the second) and 3 mg.kg(-1) for males (1 mg.kg(-1) in the first dose and 2 mg.kg(-1) in the second), with an interval of 14 hours. The determination of extrusion moment of oocytes was made by monitoring the migration of nucleus from central to peripheral position. After UTA 264.5 (accumulated thermal units) the oocytes were obtained by compression of the ventral region of the female, and male were sacrificed for extraction of sperm. The eggs were kept in an incubator and the time of hatching of larvae was 370 UTA. The larvae were initially fed with plankton and showed no cannibalism. Moreover, they were not demanding about the food, accepting prepared rations after fifteenth day of life. The weight gain of larvae was very low even close to 20 mm in length (14 days), not exceeding 0.05 mg per day. After that both weight and length increased rapidly.

MORPHOLOGICAL EVIDENCE FOR PROTANDRIC SIMULTANEOUS HERMAPHRODITISM IN THE CARIDEAN EXHIPPOLYSMATA OPLOPHOROIDES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Biological parameters and population structure of Psammobatis extenta in Ubatuba region, north coast of the State of São Paulo, Brazil

Specimens of the zipper sand skate Psammobatis extenta were collected in the region of Ubatuba off the northern coast of the State of São Paulo, Brazil, monthly for once year (January - December 2000), at 25- to 40-m isobaths. A total of 123 individuals were caught. The total length (TL) of females averaged 224.6 mm, and of males 217 mm. The overall sex ratio was 1:1. Analysis of the length-weight relationship indicated the existence of positive allometry in females, and isometry in males. The length at onset of sexual maturity was determined for both sexes; females reached sexual maturity at smaller sizes than males (TL50 = 230.7 and TL50 = 237.7 mm respectively). Females showed functional parity of both ovaries and uteri. Females that were pregnant or were carrying vitellogenic oocytes were observed during nine of 12 months of the survey, indicating a continuous reproductive cycle. Psammobatis extenta was most abundant from January to April, and again from June to October. Most individuals were collected at the 40-m isobath. Both adults and neonates were collected in the study area. However, adolescent skates were scarce, which either indicates differential occupation of the area, or suggests that the shallow waters of the continental shelf are used as breeding grounds.

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.

Histochemical studies of Rhinocricus padbergi Verhoeff ovaries (Diplopoda, Spirobolida, Rhinocricidae)

Histochemical studies of Rhinocricus padbergi Verhoeff ovaries demonstrated that the oocytes contained lipids, proteins and polysaccharides. The probable synthesis site of each is considered, and the origin and function of the Ca found is discussed.

Morphological, histological, and ultrastructural studies of the ovary of the cattle-tick Boophilus microplus (Canestrini, 1887) (Acari : Ixodidae)

This study presents the morphology of the ovary, as well as the dynamics of the vitellogenesis process in oocytes of the cattle-tick Boophilus microplus. The ovary of these individuals is of the panoistic type; therefore, it lacks nurse cells. This organ consists of a single tubular structure, continuous, and composed of a lumen delimitated by a wall of small epithelial cells with rounded nuclei. In this tick species, the oocytes were classified into six stages varying from I to VI and according to: cytoplasm appearance and presence of the germ vesicle, yolk granules, and chorion. Oocytes of various sizes and at different developmental stages remain attached to the ovary through a cellular pedicel until completing stage V. Afterwards, they are liberated into the lumen and from there to the exterior. Some oocytes (classified as type VI) showed an atypical appearance indicating that some of the cellular components would be undergoing a degenerative process and/or reabsorption. (c) 2004 Elsevier B.V. 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): Morphological description of the ovary and of vitellogenesis

The present study presents the morphology, histology, and the dynamics of vitellogenesis in females of the tick Amblyomma triste. The ovary in this species is of the panoistic type, therefore it lacks nurse cells. It is composed of a layer of epithelial cells that outwardly form the wall of the ovary, but also originate the pedicel, the structure that attaches the oocytes to its external margin, as well the oocytes themselves. In Amblyomma triste, the oocytes develop in four synchronic stages, which differs from the process in other tick species. The classification of the stages of the oocytes was carried out based on the presence of four morphologic characteristics: cytoplasm appearance; site of the germ vesicle; presence, quantity, and constitution of the yolk granules and presence of chorium. (c) 2006 Elsevier B.V. All rights reserved.

Morphological characterization of the ovary and vitellogenesis dynamics in the tick Amblyomma cajennense (Acari : Ixodidae)

In this work we describe the internal morphology of the female reproductive system of the cayenne tick Amblyomma cajennense. This system is represented by a panoistic ovary, which lacks nurse cells in the germarium. This ovary consists of a single tube, in which a large number of oocytes develop asynchronously, thus accompanying the processes of yolk deposition in the oocytes. The oocytes were classified into stages that varied from I to V, according to: cytoplasm appearance, presence of the germ vesicle, presence of yolk granules, and presence of chorion. The study of vitellogenesis dynamics suggest that the yolk elements are deposited in the oocyte following a preferencial sequence, in which the lipids are the first to appear, followed by proteins an finally by the carbohydrates. In this way the yolk of A. cajennense ticks have these three elements that may be free in the cytoplasm or chemically bounded forming glycoprotein or lipoprotein complexes. (C) 2004 Elsevier B.V. All rights reserved.