Desenvolvimento das gônadas de Dermatobia hominis (Diptera: Cuterebridae)

O trabalho descreve o desenvolvimento das gônadas do berne (D. hominis) durante o período pupal. As pupas desenvolvidas de larvas com peso superior a 650 mg, deram imagos fêmeas, enquanto que as desenvolvidas daquelas pesando entre 500 e 650 mg deram macho, tendo havido um erro ao redor de 5%. Até o oitavo dia de pupação os testículos crescem mais que os ovários; a partir daí diminui o desenvolvimento, parando de crescer entre o vigésimo e vigésimo quinto dias. A espermatogênese inicia por volta do sétimo dia de pupa quando é grande o número de espermatócitos. No décimo dia alguns testículos apresentam considerável número de espermátides e os espermatozóides começam a aparecer por volta do vigésimo dia. A espermiogênese desenvolve-se sem interrupção e ao final da pupação quase toda loja testicular está repleta de espermatózóides. Os machos começam a nascer dois dias antes das fêmeas. Nessas, os ovaríolos aparecem formados por volta do oitavo dia de pupa; os folículos se individualizam por volta do vigésimo dia de pupa onde se distingue os trofócitos com núcleos politênicos e citoplasmas bem basófilos, enquanto o ovócito tem citoplasma mais acidófilo e núcleo com cromatina bastante frouxa. A vitelogênese tem início ao redor do vigésimo quinto dia de pupa e se completa ao nascimento da imago. A ligação das gônadas com suas respectivas estruturas somáticas acontece ao redor do décimo terceiro dia de pupação.

Cytodifferentiation during the spermatogenesis of the hermaphrodite caridea Exhippolysmata oplophoroides

Among the decapods, the caridean Exhippolysmata oplophoroides has been described as a simultaneous protandric hermaphrodite, seeing that it presents a male initial stage followed by a hermaphrodite one in which it can function as male and as female. This work had the aims of characterizing the microscopical morphology of the male portion of the ovotestes gonads from E. oplophoroides, at the different development stages, identifying each cell from the germ lines during spermatogenesis, as well as describing the ultramorphology of spermatozoans in the terminal region of the vasa deferentia. Shrimps were collected in Ubatuba, north coast of São Paulo, and their male gonads and the ampoule were removed, fixed and processed according to histological routine and for scanning electron microscopy. The testicular portion is divided in lobes, inside which cells at the same stage of the spermatogenic cycle are observed, with prevalence of spermatogonia and spermatocytes at stages I, II and V of gonad development, whereas spermatids and spermatozoans are found at stages III and IV, respectively. Ultramorphology of the terminal portion of the vasa deferentia exhibits mature aflagellated spike-shaped spermatozoans, encased in secretion and between membrane foldings that will constitute the spermatophores. Despite presenting reproductive characteristics common to other decapods. E. oplophoroides shows spermatozoans as well as spermatophore with typical morphology, which is important for its identification and taxonomy. Further, this species showed polysaccharide secretions where the spermatozoa are immerse as far as the testicular portion, which could have a roe in their transport and nutrition as well as spermatophore constitution and/or fixation; differently, other caridean species begin spermatophore formation during the passage of the gametes through the vasa deferentia. (C) 2010 Elsevier Ltd. All rights reserved.

Mesabolivar brasiliensis (Moenkhaus 1898) and Mesabolivar cyaneotaeniatus (Keyserling 1891) (Araneomorphae, Pholcidae): close relationship reinforced by cytogenetic analyses

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

Cytogenetics of four Omophoita species (Coleoptera, Chrysomelidae, Alticinae): A comparative analysis using mitotic and meiotic cells submitted to the standard staining and C-banding technique

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A study of meiosis and spermiogenesis in the testicular lobes of Antiteuchus tripterus (Heteroptera : Pentatomidae)

An analysis of testicular morphology and spermatogenesis in the Heteroptera species Antileuchus tripterus (Pentatomidae) revealed that these traits differ from that recorded for other species of the same family. The testes of A. tripterus have only six lobes, while other species of the same family typically have seven lobes, including a compound lobe, i.e., a lobe containing another in its lumen. A study of meiosis and sperm structure in the different lobes of A. tripterus revealed a conventional meiosis in the lobes numbered one to three. In lobe four, however, prophase I spermatocytes exhibit the morphological characteristics of the so called diffuse stage and are larger than those in lobes 1-3 in this and the remaining phases of meiosis. Thus, the resulting spermatids are not only larger but also their head is morphologically different. Lobe 5 exhibits characteristies known from other Pentatomidae species such as an uneven distribution of chromatin to the daughter cells, which give rise to cells of different sizes. This lobe forms spermatozoa of different sizes. Lobe 6, contained within lobe 5, differs from it by having larger cells at a stage similar to the so called diffuse and spermatid tails with cross divisions, which are not found in other lobes and unreported in the literature.

Nucleolar Cycle and Its Correlation with Chromatoid Bodies in the Tilapia rendalli (Teleostei, Cichlidae) Spermatogenesis

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

Nucleolar cycle and chromatoid body formation Is there a relationship between these two processes during spermatogenesis of Dendropsophus minutus (Amphibia, Anura)?

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Short-Term Antiandrogen Flutamide Treatment Causes Structural Alterations in Somatic Cells Associated with Premature Detachment of Spermatids in the Testis of Pubertal and Adult Guinea Pigs

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

Histological aspects and structural characteristics of the testes of Dendropsophus minutus (Anura, Hylidae)

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

Relationship between the nucleolar cycle and chromatoid body formation in the spermatogenesis of Phrynops geoffroanus (Reptilia Testudines)

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

Occurrence of Nuages and Lamellae Anulata during spermatogenesis in Dermatobia hominis (Diptera: Cuterebridae)

Various types of nuages and lamellae anulata can be found during Dermatobia hominis spermatogenesis. In spermatogonia, the nuages occur as granules juxtaposed to the cytoplasmic face of the nuclear envelope or as cytoplasmic granules similar toglycogen granules. In spermatocytes, in addition to the nuages, dense spherical bodies of approximately 1.0 µm in diameter are also observed. In the spermatids the nuages can be of the following types: perinuclear granules, spherical granules with diameters varying in length from 0.5 to 1.0 µm, granules similar to glycogen granules, granules with variable diameters which accumulate at the flagellum base forming the centriole adjunct, or remain in the cytoplasm. Nuages can also be observed in these cellular types as dense masses, without a definite outline and are common to animal germinal cells in general. The lamellae anulata on the other hand, are observed only in spermatocytes I and in early spermatids, being always immersed in electron-dense material of indefinite outline. In spermatids, the lamellae anulata are close to the nuclear envelope suggesting, in spite of opposing opinions, that these cells are envolved in the synthesis and transport of material from the nucleus to the cytoplasm.

Astylus variegatus (Coleoptera, Melyridae): Cytogenetic study of a population exposed to agrochemical products

In this work we describe the cytogenetic analyses performed in specimens of Astylus variegatus (Germar, 1824) collected in two localities: one area of natural vegetation and one of agricultural crops, where agrochemical products were used. Astylus variegatus had karyotypes with 2n(male) = 16+Xy p and 2n (female) = 16+XXp, with exclusively metacentric chromosomes. Pachytene spermatocytes showed synapsed autosomal bivalents and non-associated sex chromosomes. In diplotene, the autosomal bivalents exhibited one or two terminal chiasmata and the Xy p had a typical parachute configuration. In meiotic cells of some specimens, an extra chromosome, interpreted as a B chromosome, was observed. C-banding showed constitutive heterochromatin in the pericentromeric region of all chromosomes, with the exception of the y p. Silver nitrate staining revealed one nucleolus organizer region (NOR) on the terminal region of the short arm of the second autosome pair. Silver staining of meiotic cells confirmed the NOR pattern detected in mitotic cells and revealed an argentophilous material on the Xy p. A cytogenetic comparison between the two populations of A. variegatus showed a statistically significant divergence (chi2 = 117.10; df = 1) in the number of aneuploid cells and a higher frequency of B chromosome in the population exposed to agrochemicals.

ULTRASTRUCTURE OF THE GERMINATIVE EPITHELIUM IN A GOAT WITH A 5/15-ROBERTSONIAN TRANSLOCATION

The spermatogenesis of two goats bearing a 5/15 Robertsonian translocation was investigated by electron microscopy. There was no dramatic change in the morphology of the cells of the spermatic line. All cells of the seminiferous epithelium seemed quite normal at the ultrastructural level. However a certain disturbance in the cell localization and some morphological abnormalities involving nuclear structure were seen. Spermatocytes and spermatids normal in appearance were observed, but a great number of cells presented two or more nuclei. These cells were frequently seen to become degenerated during spermatogenesis. We believe that unbalanced spermatocytes degenerate during the process and only some spermatocytes succeed in fertilizing gametes.

ULTRASTRUCTURE OF THE HINNY (EQUUS-ASINUS X EQUUS-CABALLUS) SEMINIFEROUS EPITHELIUM

The gonads and the germinative cells of 3 male hinnies were studied with light and transmission electron microscopy with the aim to observe the development of germ cells and verify the morphological modifications due to the hybridization. The hinny seminiferous epithelium presented Sertoli cells and spermatogonia with normal features and anomalous spermatocytes I. The other cells from the spermatogenic sequence were not seen. Most of the alterations began to occur in the cytes I, which presented nuclear vacuolization and deposits of amorphous material between the carioteca and the nuclear lamina, forming vesicles, or exaggerated chromatin condensation, resulting in pyknosis. In the cytoplasm vacuolization was also observed, besides organelle destruction.The arrest of meiosis due to lock of chromosome homologies leads to germinative cell degeneration and, therefore, the spermatogenesis arrest. This fact causes a profound alteration in the seminiferous epithelium morphology in comparison with the parental species.

Cytogenetics of three Brazilian Goniosoma species: A new record for diploid number in Laniatores (Opiliones, Gonyleptidae, Goniosomatinae)

Currently, 60 species of harvestmen have been karyotyped and all of these are from the Nearctic and Palearctic regions. This work is the first cytogenetic report of three gonyleptid species of the suborder Laniatores: Goniosoina aff. badiuln, G. proxiinuni and G. spelaeum of the Neotropical region, from the southeastern region of Brazil. Conventional Giemsa stain chromosome preparations were obtained from embryonic cells and adult male testes. Embryo mitotic plates of G. aff. badium and G. proximum indicated 88 chromosomes, and mitotic spermatogonial plates of G. spelaeum males revealed intra- and interindividual variation of chromosome number, ranging from 92-109 chromosomes. In the three analyzed species, the mitotic chromosomes were meta- or subinetacentric with no obvious sex chromosomes being identified during mitosis. Prophase I spermatocytes of G. spelaeum also revealed intra- and interindividual bivalent number variation and furthermore indicated the presence of multivalence. The karyotypes of these three Goniosoina species exhibited the largest chromosome pair with a negative heteropycnosis in the distal region of the shortest arrn chromosomes of G. spelaeum submitted to silver impregnation evidenced this negative heteropycnotic region as nucleolus organizer region (NOR). These results, when compared with cytogenetic data of other Laniatores species from the Palearctic region, indicated that a new record for diploid chromosome number probably characterize the genus Goniosoma in the Neotropical region.