Germinative cells and spermatogenesis of the lizard Tropidurus torquatus (Tropiduridae) from a urban area in the cerrado biome of the brazilian midwest / Células germinativas e espermatogênese do lagarto Tropidurus torquatus (Tropiduridae) de uma área urbana no bioma cerrado do centro-oeste brasileiro

Tropidurus comprises a Neotropical genus of lizard that currently has about 30 species widely distributed in the South American. Among these species, Tropidurus torquatus, which has the characteristic of great physiological plasticity, occupying a variety of habitats in open areas and urbanized environments. Considering this, the aim of the study was to investigate the germinative cells and spermatogenesis of a population of T. torquatus in an urban area under Cerrado Biome influences to understand how to establish the temporal development of germinative cells and spermatogenesis during a period of one year. Individuals were obtained in the Zoological Collection of Vertebrates at the Universidade Federal de Mato Grosso (UFMT), and the germinative cells and full spermatogenesis were described with light microscopy. Tropidurus torquatus presented germ cells with similar characteristics already documented for the other species of lizards and reptiles. Spermatogonia type A and B, primary and secondary spermatocytes, and spermatids were present in almost all months evaluated. The gonadosomatic ratio presented its highest value in October, moment in which spermatogenesis presented all the germinative cells and spermatozoa in the lumen, of the seminiferous tubules. In the seasonal climate of the Cerrado Biome, we observe discontinuous spermatogenesis in T. torquatus with the production of spermatozoa in almost every month of the year, however with sperm storage in the epididymis during the phase of testicular regression.

O gênero de lagartos neotropicais Tropidurus tem cerca de 30 espécies amplamente distribuídas no continente sul-americano. Entre essas espécies, Tropidurus torquatus é a que apresenta grande plasticidade fisiológica, ocupando uma variedade de hábitats em áreas abertas e ambientes urbanizados. Considerando isso, o objetivo do estudo foi investigar as células germinativas e a espermatogênese de uma população de T. torquatus em uma área urbana sob a influência do Bioma Cerrado para entender como é estabelecido o desenvolvimento temporal das células germinativas e a espermatogênese durante o período de um ano. Indivíduos foram obtidos na Coleção Zoológica de Vertebrados da Universidade Federal de Mato Grosso (UFMT). A caracterização das células germinativas e da espermatogênese foi realizada através de microscopia de luz. Tropidurus torquatus apresentou células germinativas com características similares às já documentadas para outras espécies de lagartos e répteis. Espermatogônias do tipo A e B, espermatócitos primários e secundários e espermátides estiveram presentes praticamente em todos os meses. A razão gonadossomática apresentou seu valor máximo em outubro, momento em que a espermatogênese apresentou todas as células germinativas e espermatozoides no lúmen do túbulo seminífero. No clima sazonal do Bioma Cerrado observamos espermatogênese descontínua em T. torquatus com a produção de espermatozoides em quase todos os meses do ano, porém com estocagem nos epidídimos durante a fase de regressão testicular.

Colon cancer and swimming exercise: effect on wistar rat testes

This study was undertaken to determine whether colon cancer (CC) and chronic swimming exercise alter rat testis. Eleven weeks old rats were distributed into control group (n=6) and the groups that were induced to develop CC by dimethylhydrazine injections (nEG, EG0, EG2 and EG4; n=10 each group). In the group nEG, the rats did not swim, whereas groups EG0, EG2 and EG4, underwent a swimming program with distinct loads (0, 2 and 4% of body mass, respectively) for 35 weeks. The morphometry, stereology and cell counts showed damage caused by the CC on the germ epithelium. These results were noteworthy since this was the first report to associate the CC with testicular damage. Swimming exercise had no significant role in reducing, or increasing the CC effects on the testis, despite having slightly improved the testis structure of the exercised rats without load. In conclusion, CC caused testis impairment, which could not be avoided by the swimming exercise.

Association of the infusion of Heteropterys aphrodisiaca and endurance training brings spermatogenetic advantages

The species Heteropterys aphrodisiaca is commonly used as a stimulant by popular medicine in the Cerrado, a savanna-like biome, Brazil. Recent studies have proved its protective effects on testes of animals submitted to treatment using Cyclosporine A, as well as its stimulus effect in increasing testosterone secretion. Therefore, the present study was designed to analyze whether the association of the plant infusion and endurance exercise could potentiate the stimulating effect. The animals were separated into 4 groups: two control (sedentary and trained) receiving water and two treated (sedentary and trained) receiving the plant infusion daily (104mg/day). The proportion of the seminiferous tubule compartment and interstitium was analyzed. Within the seminiferous epithelium, the number of Sertoli and germ cells were counted in order to evaluate whether the treatment would alter the spermatogenic dynamics, analyzing: the spermatogenic yield, the mitotic and meiotic indexes, the total number of germ cells and the Sertoli cell support capacity. Trained and treated animals showed increased spermatogenic yield and spermatogonia mitosis, and no significant differences in apoptotic indexes. Despite the results showing the same pattern regarding yield and mitotic index, the meiotic index was higher in the sedentary/treated group. Therefore, the H. aphrodisiaca infusion increased both the testosterone production and the spermatogonia mitosis, thus increasing the spermatogenic yield.

Cell death induced by tamoxifen in human blood lymphocytes cultivated in vitro / Morte celular induzida pelo tamoxifeno em linfócitos humanos cultivados in vitro

Many chemotherapeutic agents with a potential against solid tumors or leukemia can cause lymphopenia. Tamoxifen (TAM) is a synthetic non-steroidal anti-estrogen drug employed in female breast cancer treatment. The present study investigated the capacity of TAM to induce cell death in human lymphocytes cultivated in vitro. Lymphocytes were obtained from young (25-30 years; n = 3) and elderly women (58-77 years; n = 3) and cultivated for 24 or 48h, with or without TAM (20 µM). After the culture, cell viability, immunocytochemical response and ultrastructure were evaluated. TAM affected lymphocytes in a time- dependent manner, and cells obtained from elderly women were the most sensitive to TAM. Immunocytochemical analysis evidenced higher frequency of apoptosis in treated cells, and the ultrastructural study revealed autophagic vacuoles, differing from the controls. In summary, the treated lymphocytes were affected by TAM, leading to cell death by apoptosis and autophagy.

Muitos agentes quimioterápicos com potencial contra tumores sólidos ou leucemias podem causar linfopenia. O Tamoxifeno (TAM) é um agente antiestrógeno não-esteroidal empregado no tratamento de câncer de mama feminino. O presente trabalho investigou a capacidade do TAM em induzir morte celular em linfócitos humanos cultivados in vitro. Os linfócitos foram obtidos de mulheres jovens (25-30 anos; n = 3) e idosas (58-77 anos; n = 3) e cultivados por 24 ou 48h, com ou sem TAM (20 µM). Após a cultura, foram analisadas a viabilidade celular, a resposta imunocitoquímica e a ultraestrutura. Os resultados indicam que o Tamoxifeno induziu morte celular em linfócitos de ambos os grupos, entretanto, as células das mulheres idosas apresentaram-se mais sensíveis ao tratamento. A análise imunocitoquímica mostrou maior frequência de apoptose nas células tratadas e o estudo ultraestrutural revelou vacúolos autofágicos nos linfócitos expostos ao Tamoxifeno. Em conclusão, nosso estudo revelou que o TAM induziu morte celular por apoptose e autofagia.

Histology, histochemistry and ultrastructure of the oviducts and seminal receptacle of Tropidurus itambere (Rodrigues, 1987)(Reptilia: tropiduridae)

The present study found new information regarding the histology, histochemistry and ultrastructure of the oviduct of Tropidurus itambere, an inhabitant of the Brazilian Atlantic forest. Three differentiated histological regions constitute the oviduct: the infundibulum, as its main characteristic, has many tubuloalveolar glands; the uterine region is remarkable for many mucous glands, just below the epithelium; the vagina, near to the cloacal opening, is characterized by an epithelium with infolding borders and several crypts for sperm storage. The infundibulum and uterine regions were marked by the presence of acid glycosaminoglycans and neutral polysaccharides, which reacted strongly in the epithelium, and was absent in the functional gland units. In the sperm storage region, polysaccharides were not observed, occurring only in the epithelium of unicellular glands. In all structure of the oviduct, a strong staining for proteins was obtained with Xylidine Ponceau. The ultrastructural study showed a more complex stratification of the epithelium than could be seen with light microscopy, as well as a large amount of fibers and smooth muscle in the lamina propria, that suggests a role in motility. Some similarities were verified between the oviduct of the oviparous lizard, and those observed in other Reptilia and Ave. This work presents interesting differences in relation to other species of lizards and interesting similarities for phylogenetically distant groups like fish and salamanders, and may contribute to studies of physiology and reproductive morphology of the Tropiduridae family.

Ultrastructural, histological and histochemical characteristics of the epithelial wall of the seminal vesicle of mature Scaptotrigona xanthotricha moure males (Hymenoptera, apidae, meliponini)

The seminal vesicles of mature Scaptotrigona xanthotricha males were investigated using light microscopy, histochemistry and transmission electron microscopy. The globular seminal vesicles were ~450 ìm in diameter and consisted of a sperm-filled lumen and a single layer of epithelium surrounded externally by a muscular sheath. The mitochondria-rich epithelial cells had many inclusions in the basal region. These inclusions were relatively large and contained membranous structures similar to myelin figures. The epithelial cells of the seminal vesicle showed none of the features characteristically associated with a secretory function, which suggested that the material in which the spermatozoa were immersed in the vesicle lumen was produced elsewhere along the ducts and/or during sexual maturation of the males. Spermatozoa were occasionally seen inside the inclusions, which suggested a possible spermiophagic activity for this epithelium.

Morphology and ultrastructure of the spermatozoa of Scaptotrigona xanthotricha moure (Hymenoptera, Apidae, Meliponini)

The spermatozoa of Scaptotrigona xanthotricha, a stingless bee under extinction in some Brazilian states, are described. Seminal vesicles of adult males were dissected and processed for light and transmission electron microscopy. The spermatozoa were long (about 90 µm) and slender. The head consisted of an acrosome formed by an acrosomal vesicle covering the perforatorium and the nucleus. The latter was homogeneous, compact and about 11 µm long. The flagellum consisted of an axoneme, with the typical 9+9+2 microtubule arrangement that began just below the nuclear base. The two mitochondrial derivatives were asymmetric in length and diameter, and had two accessory bodies. The nucleus was attached to the flagellum by a centriolar adjunct. These results indicate that the spermatozoa of S. xanthotricha are similar to those of other Meliponini but differ markedly from other insect groups. The ultrastructure of hymenopteran spermatozoa may be a useful character for phylogenetic studies.

Dichotomic spermiogenesis in Euptoieta hegesia(Lepidoptera: Nymphalidae)

Butterflies and moths produce enucleate (apyrene) and nucleate (eupyrene) spermatozoa. However, most studies oflepidopteran spermatogenesis and spermiogenesis have used only larvae and pupae. In this work, we used light andtransmission electron microscopy to examine spermiogenesis in males of the butterfly Euptoieta hegesia. Only adultmales were used, because this species has a long adult lifespan during which all cell stages can be observed. Male E.hegesia had a single fused testis with cysts that exclusively contained either apyrene or eupyrene cells. The mainevents of apyrene spermiogenesis included the formation, transformation and elimination of micronuclei, dense capformation, the development of mitochondrial derivatives and tail elongation. Eupyrene spermiogenesis involvedacrosome formation, nuclear condensation and elongation, extracellular appendage development, formation ofmitochondrial derivatives and tail elongation. The pattern and events of apyrene and eupyrene spermiogenesis in E.hegesia corroborate and complement data in the literature, particularly with regard to the intermediate developmentalstages of some structures, such as the acrosome, axoneme and extracellular appendages.

Reproductive cycle of male green iguanas, Iguana iguana (reptilla: sauria: iguanidae), in the Pantanal region of Brazil

Adult male green iguana (Iguana iguana) (n=10) were collected in different seasons in the Brazilian Pantanal and their testes were examined using light and scanning electron microscopy. The annual reproductive cycle involved four stages which alternated between a maximum and a minimum of spermatogenesis. During the cycle, there was an inversely proportional relationship between the development of the semibiferous tubules and the interstitial tissue. In the first stage of the cycle (October-December, inundation season) there was minimum spermatogenesis, with only the initial divisions of spertogonia, whereas the interstitial tissue and Leydig cells were well developed. This state continued during the second stage (January-March, flood season) with initial germ cell development and a reduction in interstitial tissue. In the third stage (April-June, drainage season) there was maximal germ cell activity with all phases of cell maturation present whereas the interstitial tissue was greatly reduced. Spermiation occurred in the last stage (July-September, dry season) and left large amounts of residual cytoplasm in the seminiferous tubule lumen. The possible social and environmental implications of this cycle are discussed.

Basic nuclear protein substituition during spermiogenesis in Hyla ranki (Amphibia, Anura, Hylidae

One of the most noticeable modifications observed during spermatic differentiation is the change in nuclear shape and especially chromatin condensation. This study was undertaken to determine nuclear modifications during spermiogenesis in Hyla ranki taking into account patterns of nuclear basophilia, nuclear condensation and elongation. Adult testes processed for light microscopy were stained with toluidine blue at PH 4.0, and those used for transmission electron microscopy were processed using the ethanolic phosphotungstic acid (E-PTA) method for basic proteins. Toluidine blue-treated material exhibited a different basophilic response as a function of the degree of cell maturation, the same variation occurring in relation to the nuclear density seen with the electron microscope. By using both staining methods, it is assumed that during cytodifferentiation of the spermatic cells of Hyla ranki, the high degree of chromation condensation is possibly related to the appearance of a protamine-like protein which substitutes somatic histones or associates to these, giving rise to a tighter DNA-protein complex.

Nuclear ultrastructure of malpighian tubule cells in Triatoma infestans (Hemiptera, Reduviidae) under conditions of full nourishment and starvation

A ultra-estrutura de núcleos, com ênfase complexo cromocentro-nucléolo, foi estudada em células dos túbulos de Malpighi de espécimes de Triatoma infestans bem alimentados e sob jejum. Foram observadas, pelo menos em parte dos núcleos dos insetos em jejum, alteraçöes envolvendo o aparecimento de grânulos de paricromatina na zona superficial dos cromocentros näo em contato com componentes nucleares, desaparecimento total ou parcial dos elementos do nucleolonema e decréscimo na elétron-opacidade de alguns cromocentros. Admite-se que esta última esteja associada à descompactaçäo de heterocromatina induzida pelo "stress" e sugerida anteriormente com análise de imagem. O aspecto ultraestrutural dos núcleos 24 horas após os insetos em jejum se alimentarem praticamente näo difere daquele dos controles bem alimentados. Pequenos grânulos näo descorados com o método do EDTA, descrito como corando preferncialmente RNA, foram encontrados no interior de cromocentros de insetos bem alimentados ou naqueles que se alimentaram após o jejum. Estas áreas coradas säo admitidas como regiöes dos cromocentros contendo cromatina menos firmemente empacotada e säo especuladas como possíveis sítios com algum potencial transcritivo