Patterns of nucleolar activity during spermatogenesis of two triatomines, Panstrongylus megistus and P-herreri

The present work analyzed spermatogenesis in two species of triatomines (genus Panstrongylus) using silver-ion impregnation. The sex chromosomes of P. megistus and P. herreri had nucleolar organizing activity and became strongly impregnated during the phases of meiotic prophase I. Fragmentation of the nucleolus occurred in both species during the meiotic cycle. The nucleolar region could be observed up to diakinesis in meiotic prophase after which only nucleolar bodies and fragments were seen. Postmeiotic reactivation of rRNA synthesis occurred in these two species and was probably related to cell differentiation.

Karyotype and spermatogenesis in Triatoma lenti (Hemiptera: Triatominae), a potential Chagas vector

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

Chromatoid body: Remnants of nucleolar proteins during spermatogenesis in triatomine (Heteroptera, Triatominae)

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

Spermatogenesis and nucleolar activity in Triatoma klugi (Triatomine, Heteroptera)

Triatoma klugi is a Chagas disease vector in the Rio Grande do Sul State. Triatominae chromosomes are holocentric and sex chromosomes segregation is post-reductional. In this paper we describe the karyotype of male T. klugi and a meiotic analysis including the nucleolar behavior during spermatogenesis. Testis cells were analyzed after lacto-acetic orcein and silver nitrate staining. Two autosomes and the heterochromosomes presented nucleolar activity (Ag-NORs) during diplotene-diakinesis. The analysis of metaphase I and II revealed a karyotype with 2n = 20+XY. In metaphase I a prominent nucleolar mass was observed in the cell periphery and small silver grains were detected in metaphase II. During anaphase, the chromosomes segregated in parallel and a typical holocentric late migration behavior was observed. The restoration of the nucleolus was an important feature in this phase. During telophase nucleolar masses persisted and in early spermiogenesis the spermatids presented a small peripheral mass until elongation. The present study is a contribution to the study of chromatin behavior and nucleolar persistence in meiosis.

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)

Comparative analysis of the testes and spermatogenesis in species of the family Pentatomidae (Heteroptera)

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

Ultrastructure of spermatogenesis in the white-lined broad-nosed bat, Platyrrhinus lineatus (Chiroptera: Phyllostomidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Characterization of Mongolian Gerbil Chromatoid Bodies and Their Correlation with Nucleolar Cycle During Spermatogenesis

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Ultrastructural characteristics of spermatogenesis in Pallas's mastiff bat, Molossus molossus (Chiroptera: Molossidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Meiosis, spermatogenesis and nucleolar behavior in the seminiferous tubules of Alydidae, Coreidae and Rhopalidae (Heteroptera) species.

We studied the karyotype, spermatogenesis and nucleolar activity at spermatogenesis in five species of Heteropera: Hyalymenus sp and Neomegalotomus pallescens, Alydidae; Catorhintha guttula and Hypselonotus fulvus, Coreidae; and Niesthrea sidae, Rhopalidae. They showed a red (Alydidae) or orange (Coreidae and Rhopalidae) membrane covering the testes, which consisted of seven testicular lobes, except in N. pallescens, which had only five. All the species had m-chromosomes, an X0 sex chromosome system and 10 (Hyalymenus sp, N. pallescens, and N. sidae), 16 (H. fulvus) or 22 (C. guttula) autosomes. Similar to the other species described to date, all these species showed holocentric chromosomes, interstitial chiasmata in most autosomes, and autosomes dividing reductionally in the first meiotic division and equationally in the second, while sex chromosomes, divided equationally and reductionally in the first and second meiotic divisions, respectively. In addition, we observed that the sex chromosome is heteropycnotic at prophase and that heteropycnotic chromosomal material is found in the nuclei at spermatogenesis; variation in size, shape and location of the nucleolar material occurs during spermatogenesis, denoting a variable degree of activity in the different stages.

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.

Morphofunctional changes in Leydig cells throughout the continuous spermatogenesis of the freshwater teleost fish, Serrasalmus spilopleura (Characiformes, Characidae): an ultrastructural and enzyme study

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