Energy substrate utilization during nightly vocal activity in three species of Scinax (Anura/Hylidae)

Anuran amphibians exhibit different patterns of energy substrate utilization that correlate with the intensity of vocal and locomotor activities. Given the remarkable differences among species in breeding and feeding strategies, and the different ways energy is used in the whole animal, the suggested correlations between calling and locomotor behavior and the level of energy substrates in the muscles responsible for such activities are more complex than previously reported. We explored the relationships between calling and locomotor behavior and energy supply to trunk and hindlimb muscles, respectively, within the ecologically diverse tree-frog genus Scinax. Specifically, we measured the relative amount of carbohydrates and lipids in these two groups of muscles, and in the liver of three species of Scinax that differ in vocal and locomotor performance, and compared our results with those of two other species for which comparable data are available. We also compared the contents of lipids and carbohydrates of conspecific males collected at the beginning and after 4 h of calling activity. The stomach content to potential feeding opportunities across species was also assessed in both groups of males. Scinax hiemalis and S. rizibilis exhibit comparatively low and episodic calling during long periods of activity whereas S. crospedospilus calls at higher rates over shorter periods. Male S. hiemalis had highest levels of trunk muscle glycogen followed by those of S. rizilbilis and S. crospedospilus, respectively. There was no correlation between total lipid content in trunk muscle and calling rate among different species, suggesting that other metabolic aspects may be responsible for the energetic support for vocal activity. The levels of lipids and carbohydrates in trunk and hindlimb muscles and liver of males collected at the beginning and 4 h into the calling period were similar across species, so the extent of energetic reserves does not appear to constrain vocal or locomotor activity. Finally, we found exceptionally high levels of carbohydrates and lipids in the liver of S. rizibilis, a trait perhaps related to a long and demanding breeding period.

Natural killer activity in the experimental privational rickets

To study the 'in vivo' importance of vitamin D on the natural killer (NK) activity, rats were submitted to privational rickets induced by a diet deficient in vitamin D and phosphorus (D-P-). Thirty days after the beginning of treatment the animals showed low body weight, changes in the bone development, and decreased levels of 25-hydroxyvitamin D-3 (25-OH D-3). NK activity, evaluated using a cytotoxicity assay against Cr-51-labeled Yac.1 target cells, was not modified by the rickets-inducing treatment during the first 30 days. Following a long-term treatment (60 days) the rachitic rats (D-P-) exhibited higher NK activity than control animals (D + P +) (P < 0.05). on the other hand, D - P + animals showed higher cytotoxic activity than D - P - and D + P + groups. Feed replacement to the rachitic rats by a complete diet (D - P - /D + P +) led to a partial recuperation of growth, bone development, and 25-OH D-3 scrum. levels. The NK activity was also influenced by vitamin D intake, decreasing after treatment. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Characterisation of protease activity in extracellular products secreted by Giardia duodenalis trophozoites treated with propolis

Results from our laboratory revealed propolis activity on Giardia trophozoites proliferation. Since therapeutic agents can inhibit the activity of proteases related to relevant biologic and physiologic processes of parasites, this study was undertaken to characterise the proteolytic activity of excretory/secretory products (ESP) of trophozoites treated with propolis. ESP was obtained from culture supernatants of trophozoites exposed to 250 and 500 mu g mL(-1) of propolis. ESP were tested in sodium dodecyl sulfate-polyacrylamide gel electrophoresis for the protein profiles and the protease activity was assayed in gelatin-containing gels. Synthetic inhibitors were used to characterise the protease classes. Treated and non-treated ESP showed a similar protein and hydrolysis pattern. A simple pattern of protein composed by five evident bands of approximately 167, 132, 79, 61 and 51 kDa was found, and the zymograms comprised hydrolysis zones distributed from > 170 to 23 kDa. No inhibition was seen on protease activity of propolis-treated trophozoites, whose hydrolysis pattern was similar to control. One may conclude that both ESP degraded gelatin and the activity was predominantly due to cysteine proteases. Although propolis had no effect on the proteolytic activity, further studies could identify the active constituents responsible for propolis antigiardial activity and their mechanisms of action.

Nitric oxide synthase activity in tissues of the blowfly Chrysomya megacephala (Fabricius, 1794)

Although insects lack the adaptive immune response of the mammalians, they manifest effective innate immune responses, which include both cellular and Immoral components. Cellular responses are mediated by hemocytes, and Immoral responses include the activation of proteolytic cascades that initiate many events, including NO production. In mammals, nitric oxide synthases (NOSs) are also present in the endothelium, the brain, the adrenal glands, and the platelets. Studies on the distribution of NO-producing systems in invertebrates have revealed functional similarities between NOS in this group and vertebrates. We attempted to localize NOS activity in tissues of naive (UIL), yeast-injected (YIL), and saline-injected (SIL) larvae of the blowfly Chrysomya megacephala, using the NADPH diaphorase technique. Our findings revealed similar levels of NOS activity in muscle, fat body, Malpighian tubule, gut, and brain, suggesting that NO synthesis may not be involved in the immune response of these larval systems. These results were compared to many studies that recorded the involvement of NO in various physiological functions of insects.

Finasteride treatment alters MMP-2 and-9 gene expression and activity in the rat ventral prostate

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

Protease activity in Giardia duodenalis trophozoites of axenic strains isolated from symptomatic and asymptomatic patients

We have examined by gelatin-SDS-PAGE the protease activity in cell lysates of Giardia duodenalis trophozoites of two axenic strains isolated in Brazil from a symptomatic patient (BTU-11) and an asymptomatic carrier (BTU-10), and the reference strain Portland 1 (P1). The proteolysis band patterns showed differences among strains isolated from asymptomatic and symptomatic individuals. The lysate of the strain BTU-10, showed only five hydrolysis bands, while a greater number of bands (10-11 bands) was seen in strains BTU-11 and P1. The protease activity in all lysates was inhibited by cysteine (E-64 and iodoacetamide) and serine proteases (TPCK and TLCK) inhibitors, but not by PMSF and EDTA. In general, the results revealed protease activities in G. duodenalis trophozoites of Brazilian axenic strains and the predominance of cysteine proteinases. It should be stressed the inter-strain difference in hydrolysis band patterns observed between strains isolated from symptomatic patients and the strain obtained from an asymptomatic carrier.

Partial characterization of proteolytic activity in Giardia duodenalis purified proteins

O presente estudo consiste em uma caracterização preliminar da atividade proteolítica de frações de proteínas purificadas a partir de lisados de trofozoítos de cepa isolada e axenizada no Brasil. Frações obtidas por cromatografia líquida (FPLC) foram analisadas quanto ao perfil eletroforético em géis de poliacrilamida (SDS-PAGE) e a atividade proteolítica foi avaliada em géis contendo gelatina como substrato. A caracterização das enzimas foi realizada a partir da análise do efeito de inibidores sintéticos de cisteína-proteases (E-64, IAA), serina-proteases (PMSF), serina e cisteína-proteases (TPCK, TLCK, elastatinal), metalo-proteases (EDTA) e aspartil proteases (pepstatina) sobre a degradação do substrato. Entre 30 frações eluídas, bandas de proteínas foram observadas em oito delas, entretanto, atividade proteolítica foi detectada apenas nas frações 23, 24, 25 e 26. O perfil eletroforético das proteínas revelou poucas bandas distribuídas na faixa de 45 a 18 kDa. Os zimogramas revelaram zonas de proteólise na faixa de aproximadamente 62 a 35 kDa, entretanto destacaram-se as bandas de hidrólise de 62, 55, 53, 50, 46 e 40 kDa. Nos ensaios de inibição, a proteólise foi marcantemente inibida por E-64, TPCK, TLCK e elastatinal. Redução discreta da proteólise foi observada com IAA e PMSF, enquanto que EDTA e pepstatina não promoveram alteração dos perfis de hidrólise. Estas observações são relevantes, especialmente se considerarmos que para elucidar o envolvimento das proteases na relação parasita-hospedeiro, a purificação dessas moléculas é um requisito importante.

Nuclear activity in Apis mellifera L. (Hymenoptera, Apidae) queen ovary cells demonstrated by silver nitrate impregnation and ultrastructure

Este estudo mostra, por meio de microscopia convencional, impregnação por nitrato de prata e microscopia eletrônica de transmissão, as mudanças que ocorrem na atividade nuclear de células do ovário durante a vitelogênese de Apis mellifera (Linnaeus, 1758). Material impregnado por nitrato de prata foi detectado no núcleo de células nutridoras, na vesícula germinal do ovócito e no núcleo das células foliculares. As maiores quantidades de material impregnado pela prata foram observadas durante as fases de maior atividade dessas estruturas. A impregnação por prata permitiu demonstrar que a vesícula germinal sintetiza ribonucleoproteínas (RNP) durante o início da vitelogênese. A ultraestrutura mostrou que o material impregnado apresenta características morfológicas de nucléolos.

Depressive symptoms and level of physical activity in patients with Alzheimer's disease

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

Stages of behavior change and perceived barriers to physical activity in the elderly living in a medium size city in Brazil

The aim was to analyze the prevalence of the stages of behavior change (BCS) and the perceived barriers to physical activity in older people residents in a medium size city of São Paulo state, Brazil. Seventy-nine older people participated of the study. The BCS was assessed by the Questionnaire of Behavior Chance Stages and those on perception of barriers by the Questionnaire on Barriers to the Practice of Physical Activity in Older People (QBPPAE). Statistical analyses was comprised by the Chi-square test (p<0.05). Data showed that: a) 64,6% of the older people do not practice physical activity and only 22,8% of them have been practicing it on a regular basis for more than 6 months; b) The most perceived barriers were: "Active enough", "Too old"; "Need to rest" and; "Disease or injury"; c) The BCS seems modulate significantly the perception of barriers (p<0.05). We can conclude that: a) most of the older people are in the pre-contemplation, contemplation and preparation stages of the BCS, yet; b) gender influences almost nothing with perception of barriers and; c) the BCS interferes with the type of perceived barriers. Such conclusions support the suggestions that it is necessary to develop specific strategies for different stages of behavior change if it is to minimize the barriers. This may help to find the most effective way to change to more active lifestyle in the elderly.

Peroxidase activity in Malpighian tubules of Triatoma infestans Klug

Benzidine and diamino benzidine (DAB) oxidation, typically performed by peroxidases, was demonstrated by light and electron microscopy in peroxisomes, mitochondria and membranous structures which occurred in close contact with urate crystals in Malpighian tubules of nymphs and adults of Triatoma infestans. Peroxisomes were predominantly identified in cells of the distal region of the tubules, which is engaged in excretory mechanisms. DAB oxidation in mitochondria, even in the absence of hydrogen peroxide, may indicate the existence of a mitochondrial peroxidase and possibly a cytochrome c peroxidase. The localization of the extracellular membranous structures appeared restricted to the lumen of the proximal region of the tubules and they were assumed to be remnants of endoplasmic reticulum containing peroxidases.

Meiosis aspects and nucleolar activity in Triatoma vitticeps (Triatominae, Heteroptera)

Some aspects of both the nucleolar organizer activity and meiosis were studied in the testes of Triatoma vitticeps (Heteroptera, Triatominae). The techniques used included squashing followed by lacto-acetic orcein staining, silver-ion impregnation, fluorescent banding (CMA(3), Quinacrine mustard and DAPI) and fluorescent in situ hybridization (FISH). A close relationship between heterochromatin and nucleolus in testicular cells was observed. During meiosis, the silver-ion impregnation pattern varied. At metaphase plate, a small body appeared apart from the chromosomes. In the spermatids this small body was seen in preparations stained with orcein and silver- ion impregnation but not with fluorochromes or FISH. These characteristics combined suggest that these corpuscles represent a source of ribonucleoproteins (RNP) - RNA and specific nucleolar proteins. Silver-ion impregnation and (FISH) revealed nucleolar organizer activity in two metaphase sex chromosomes (X). These results indicate that, in these species, nucleolar organizer regions (NORs) are located in the sex chromosomes, X chromosomes were were CMA(3)(+) and Y chromosome was DAPI(+).

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.

Localized matrix metalloproteinase (MMP)-2 and MMP-9 activity in the rat ventral prostate during the first week of postnatal development

The initial events in prostatic morphogenesis involve cell proliferation, epithelial canalization and outgrowth toward the stroma. We have hypothesized that stromal rearrangement takes place at the sites of epithelial growth and branching and that this rearrangement involves the action of gelatinases matrix metalloproteinase (MMP)-2 and MMP-9. Thus, the purpose of the present study was to characterize structural aspects of epithelial growth during the first week of postnatal development of the rat ventral prostate and to investigate the expression, localization and activity of MMP-2 and MMP-9 during this period by histological, ultrastructural and immunocytochemical analysis, in addition to gel zymography, in situ zymography and Western blotting. An increasing complexity of prostatic architeture was observed within the first postnatal week. Concurrently, the stroma became more organized and some cells differentiated into smooth muscle cells. Reticulin fibers appeared in a basket-like arrangement around both growing tips and epithelial sprouts, associated with a fainter staining for laminin. MMP-2 and MMP-9 activities were detected. MMP-2/MMP-9 expression decreased during the first week. Developing epithelial cords showed strong and difuse gelatinolytic activity. This activity coincided with the distribution of MMP-2 as determined by immunocytochemistry. on the other hand, MMP-9 was rather concentrated at the epithelial tips. These results suggest that gelatinolytic activity (with contribution of both MMP-2 and MMP-9) in the epithelium and at the epithelium-stroma interface are at least in part responsible for the tissue remodeling that allows epithelial growth and its projection into the surrounding stroma.