Morphometry of the midgut of Melipona quadrifasciata anthidioides (Lepeletier) (Hymenoptera: Apidae) during metamorphosis

In Hymenoptera, midgut changes begin in the last instar. At this stage, the larval epithelial digestive cells degenerate, leaving only the basal membrane and the regenerative cells which will develop into a new epithelium during the pupal stage and in the adult. Epithelium renewal is followed by changes in volume and shape of the midgut. Morphometric analysis of digestive cells and total midgut volume of Melipona quadrifasciata anthidioides (Lepeletier) were conducted to verify whether cell volume increase are sufficient to account for the total midgut volume increase that occurs during metamorphosis. An increase in midgut volume was verified in spite of the scarcity of cell proliferation found during metamorphosis. At the end of metamorphosis, the increase in cell volume was not sufficient to explain the increase in volume of the midgut, indicating that an increase in the number of digestive cells is apparently necessary. Nevertheless, the mechanism by which regenerative cells reconstitute the epithelium during metamorphosis remains unknown.

Does heteropterys aphrodisiaca administration andendurance training alter bones of mature rats?

Heteropterys aphrodisiaca infusion, alone or associated with endurance training, was investigated in rat bonesin relation to their mechanical properties, collagen content and morphology. Male rats were divided into fourgroups (n = 8): CS- control sedentary, HS- H. aphrodisiaca sedentary, CT–control trained, HT‑H. aphrodisiacatrained. The training protocol consisted in running on a motorized treadmill, 5 times a week, for 8 weeks,with weekly increase in treadmill velocity and duration. Control groups received water while HS and HTgroups received H. aphrodisiaca infusion (104 mg/animal) by gavage during the 8 weeks. Tibiae werefrozen for collagen dosage and biomechanical analysis or preserved in Karnovsky’s fixative, then processedfor histomorphological analysis by conventional light microscopy and scanning electron microscopy. TheHT group showed significantly higher yield load and yield stress in the tibiae three-point bending test. Themaximum load, stiffness, maximum stress and elastic modulus were statistically similar for the experimentalgroups. The hydroxyproline content, morphometrical and stereological data were not significantly differentfor the four groups. Scanning electron microscopy showed more lacunae and Havers canals in the bone oftrained animals, moreover the osteons were more disorganized, when compared with sedentary groups. Thesealterations may indicate that the bone of trained animals was being remodeled. However, after 8 weeks oftraining, it was not possible verify alterations in morphometrical measurements, collagen content, stiffness andmodulus of elasticity of the trained and treated animals.

Characteristics of the Male Reproductive System and Spermatozoa of Leptophlebiidae (Ephemeroptera)

This study describes morphological changes in the male reproductive system of Miroculis amazonicus (Savage & Peters) from mature nymphs to subimago stages. The sperm ultrastructure of Massartela brieni (Lestage), Farrodes carioca (Domínguez et al) and Miroculis mourei (Savage & Peters), as well as aspects of cell fragments observed in these species' subimagos deferent ducts were described. Sperm from the three species studied are aflagellated and immotile, while those from F. carioca and Ma. brieni are approximately spherical with a homogenous nucleus and acrosome. Sperm of F. carioca present two or three mitochondria located between the nucleus and the acrosome. In Ma. brieni, only one lateral mitochondria was found. Sperm from Mi. mourei are shaped as a number 'eight', with electron lucent spots inside the nucleus and two mitochondria above the acrosome. Large cell fragments containing degenerative vesicles and some sperm were observed in the deferent duct lumen of the three species. Testes of Mi. amazonicus are extremely reduced in the subimago stage, which suggests that these cell fragments originated from testes degeneration.

Seasonal changes in testicular and epididymal histology of the tropical lizard, Tropidurus itambere (Rodrigues, 1987), during its reproductive cycle / Mudanças sazonais na histologia do testículo e epidídimo do lagarto tropical Tropidurus itambere, durante seu ciclo reprodutivo

The reproductive cycles of lizards, including Tropidurus species, have been widely studied. However, few studies describe in detail the ultrastructure and the epithelial changes in the epididymis. Using histology and trasmission electron microscopy, we show the seasonal changes in the testis and epididymis of the lizard Tropidurus itambere, during its annual reproductive cycle. The reproductive cycle of T. itambere was analysed from June 1988 to June 1989 and from June 2001 to June 2002. While the frequency of reproductive males in the population varied throughout the year, there were reproductive males in most months except for February through April. During this nonreproductive period, there is a reduction in the mean seminiferous tubule volume and few sperm were found in both the testis and the epididymis.

O ciclo reprodutivo de alguns lagartos já foi extensamente estudado, incluindo algumas espécies do gênero Tropidurus. Entretanto, poucos estudos mostram os aspectos morfológicos do testículo e epidídimo, durante o ciclo reprodutivo anual, e não existe nenhuma descrição ultraestrutural das variações epiteliais no epidídimo. O presente estudo foi feito para mostrar, através da histologia e microscopia eletrônica de transmissão, detalhes das mudanças sazonais no testículo e epidídimo durante o ciclo reprodutivo anual. Acompanhamos o ciclo de Tropidurus itambere, na floresta atlântica brasileira, durante o período de junho de 2001 a junho de 2002. Os machos variam em sua atividade reprodutiva, mas foram considerados potencialmente reprodutivos na maioria dos meses, à exceção dos meses de fevereiro a abril. Durante este período, ocorreu uma redução no volume médio dos túbulos seminíferos e uma menor quantidade de espermatozóides no testículo e no epidídimo.

Use of blends of bioabsorbable poly(L-lactic acid)/poly(hydroxybutyrate- co-hydroxyvalerate) as surfaces for Vero cell culture

Vero cells, a cell line established from the kidney of the African green monkey (Cercopithecus aethiops), were cultured in F-10 Ham medium supplemented with 10 percent fetal calf serum at 37°C on membranes of poly(L-lactic acid) (PLLA), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and their blends in different proportions (100/0, 60/40, 50/50, 40/60, and 0/100). The present study evaluated morphology of cells grown on different polymeric substrates after 24 h of culture by scanning electron microscopy. Cell adhesion was also analyzed after 2 h of inoculation. For cell growth evaluation, the cells were maintained in culture for 48, 120, 240, and 360 h. For cytochemical study, the cells were cultured for 120 or 240 h, fixed, processed for histological analysis, and stained with Toluidine blue, pH 4.0, and Xylidine ponceau, pH 2.5. Our results showed that cell adhesion was better when 60/40 and 50/50 blends were used although cells were able to grow and proliferate on all blends tested. When using PLLA/PHBV (50/50) slightly flattened cells were observed on porous and smooth areas. PLLA/PHBV (40/60) blends presented flattened cells on smooth areas. PLLA/PHBV (0/100), which presented no pores, also supported spreading cells interconnected by thin filaments. Histological sections showed that cells grew as a confluent monolayer on different substrates. Cytochemical analysis showed basophilic cells, indicating a large amount of RNA and proteins. Hence, we detected changes in cell morphology induced by alterations in blend proportions. This suggests that the cells changed their differentiation pattern when on various PLLA/PHBV blend surfaces.

Sperm ultrastructure and spermatogenesis in the lizard, Tropidurus itambere

Spermatogenesis, with emphasis on spermiogenesis, is described for the lizard, Tropidurus itambere, using light microscopy, phase contrast and epifluorescence, as well as scanning and transmission electron microscopy. Cellular differentiation involves events of chromatin condensation, nuclear elongation and the formation of structural complexes, such as the acrosomal and axonemal ones. Other new characteristics, exclusive for this species, include various aspects of the subacrosomal granule, the insertion of the pro-acrosomal vesicle and the development of these structures to participate in the acrosomal complex. Radial projections occurjust above the nuclear shoulders, which have been recognized already from the beginning of cellular elongation. The development of the midpiece, the dense bodies, formation of the flagellum and elimination of residual cytoplasm result in the final characterization of the mature spermatozoon. Comparisons between Tropiduridae and other lizard families are made.