Phytochemical characterization of the Vochysia rufa (Vochysiaceae) extract and its effects on oxidative stress in the pancreata of streptozotocin-induced diabetic rats.

Aqueous extract of macerated Vochysia rufa stem bark has been commonly used in the treatment of diabetes. Therefore, we evaluated the antihyperglycemic and antioxidant effects of an extract of V. rufa on the pancreata of streptozotocin (STZ)-induced diabetic rats. Animals received one of the following treatments daily by oral gavage: water (diabetic-control), V. rufa extract (diabetic-V. rufa), or glibenclamide (diabetic-GBD). Total antioxidant capacity; levels of thiobarbituric acid reactive substances, reduced glutathione, and sulfhydryls; and superoxide dismutase, catalase, and glutathione peroxidase (GPx) activities were measured in the pancreas. Biochemical analysis of serum total cholesterol and fractions, triglycerides, creatinine, urea, acid uric, ALP, γ-GT, AST, and ALT was performed, and pancreatic ß-cells positive for insulin were evaluated by immunohistochemistry. Rats treated with extract exhibited a decrease in fasting blood glucose compared with levels in diabetic control rats. GPx activity and sulfhydryl levels were significantly lower in diabetic-V. rufa rats compared with those of diabetic-control rats. V. rufa extract acted to normalize the biochemical alterations found in diabetic rats (diabetic-controls), as demonstrated by increases in urea, HDL, ALP, AST, and ALT. Reduction in blood glucose was independent of an increase in insulin. The V. rufa extract was found to be composed of free sugars (inositol, galactose, glucose, mannose, sucrose, arabinose, and ribose) as the main metabolites. Thus, aqueous extract of the stem bark of V. rufa is capable of reducing blood glucose, resulting in an antioxidant effect on the pancreatic tissue of STZ-diabetic rats.

Phaseolamin treatment prevents oxidative stress and collagen deposition in the hearts of streptozotocin-induced diabetic rats.

The development of cardiovascular complications in patients with diabetes is often associated with an imbalance between reactive oxygen species and antioxidant systems. This imbalance can contribute to high cardiac collagen content, which increases cross-linking and the stiffness of the myocardium. In this study, the protective effect of phaseolamin against damage under oxidative stress and collagen deposition in the cardiac tissue in association with diabetes was evaluated. Non-diabetic and diabetic animals were distributed into groups and treated for 20 days with commercial phaseolamin. The phaseolamin treatment increased total antioxidant activity but reduced the following in diabetic rats: (a) hyperglycaemic state, (b) catalase and superoxide dismutase activity and (c) tissue damage caused by lipid peroxidation. Additionally, the phaseolamin treatment attenuated the collagen levels compared to non-treated diabetic rats. Thus, the short-term anti-hyperglycaemic effect of the phaseolamin treatment may prevent the initial changes caused by oxidative stress and the deposition of collagen, as well as reduce the incidence of heart complications.

Worker honeybee brain proteome.

A large-scale mapping of the worker honeybee brain proteome was achieved by MudPIT. We identified 2742 proteins from forager and nurse honeybee brain samples; 17% of the total proteins were found to be differentially expressed by spectral count sampling statistics and a G-test. Sequences were compared with the EuKaryotic Orthologous Groups (KOG) catalog set using BLASTX and then categorized into the major KOG categories of most similar sequences. According to this categorization, nurse brain showed increased expression of proteins implicated in translation, ribosomal structure, and biogenesis (14.5%) compared with forager (1.8%). Experienced foragers overexpressed proteins involved in energy production and conversion, showing an extensive difference in this set of proteins (17%) in relation to the nurse subcaste (0.6%). Examples of proteins selectively expressed in each subcaste were analyzed. A comparison between these MudPIT experiments and previous 2-DE experiments revealed nine coincident proteins differentially expressed in both methodologies.

A metallic impregnation technique adapted to study the honeybee Apis mellifera L. brain.

In order to visualize the distribution pattern of the neuronal bodies and neurofibrils in the honeybee brain, we adapted a metallic impregnation technique first described for vertebrate nervous system by Ramón y Cajal. The honeybee brain constitution plays a key role in the development of learning and memory capacities. The general characteristics observed in the honeybee brain, stained by metallic impregnation, revealed its anatomical and morphological constitution in agreement with studies of other insect brains using different techniques. Metallic impregnation evidenced the optic lobe neuropils, the ocelli fiber cells, the neuron extensions of the calyces, and the axon bundles that involve the antennal glomeruli, as well as the neuron extensions in the alpha lobe. We also observed that the antennal glomeruli were mainly formed by fibers. The optical lobes were impregnated distinctly in the monopolar neuron bodies and in the fibers. In the mushroom bodies, we observed the lip, collar and calyx basal areas. Based on our results, the metallic impregnation technique is effective to visualize neuronal bodies and neurofibrils; moreover, is simpler and faster than other techniques, offering new insights for the investigation of the invertebrate nervous system.

A metallic impregnation technique adapted to study the honeybee Apis mellifera L. brain

In order to visualize the distribution pattern of the neuronal bodies and neurofibrils in the honeybee brain, we adapted a metallic impregnation technique first described for vertebrate nervous system by Ramón y Cajal. The honeybee brain constitution plays a key role in the development of learning and memory capacities. The general characteristics observed in the honeybee brain, stained by metallic impregnation, revealed its anatomical and morphological constitution in agreement with studies of other insect brains using different techniques. Metallic impregnation evidenced the optic lobe neuropils, the ocelli fiber cells, the neuron extensions of the calyces, and the axon bundles that involve the antennal glomeruli, as well as the neuron extensions in the alpha lobe. We also observed that the antennal glomeruli were mainly formed by fibers. The optical lobes were impregnated distinctly in the monopolar neuron bodies and in the fibers. In the mushroom bodies, we observed the lip, collar and calyx basal areas. Based on our results, the metallic impregnation technique is effective to visualize neuronal bodies and neurofibrils; moreover, is simpler and faster than other techniques, offering new insights for the investigation of the invertebrate nervous system.

Localization of myosin-Va in subpopulations of cells in rat endocrine organs.

Myosin-Va is a Ca(2+)/calmodulin-regulated unconventional myosin involved in the transport of vesicles, membranous organelles, and macromolecular complexes composed of proteins and mRNA. The cellular localization of myosin-Va has been described in great detail in several vertebrate cell types, including neurons, melanocytes, lymphocytes, auditory tissues, and a number of cultured cells. Here, we provide an immunohistochemical view of the tissue distribution of myosin-Va in the major endocrine organs. Myosin-Va is highly expressed in the pineal and pituitary glands and in specific cell populations of other endocrine glands, especially the parafollicular cells of the thyroid, the principal cells of the parathyroid, the islets of Langerhans of the pancreas, the chromaffin cells of the adrenal medulla, and a subpopulation of interstitial testicular cells. Weak to moderate staining has been detected in steroidogenic cells of the adrenal cortex, ovary, and Leydig cells. Myosin-Va has also been localized to non-endocrine cells, such as the germ cells of the seminiferous epithelium and maturing oocytes and in the intercalated ducts of the exocrine pancreas. These data provide the first systematic description of myosin-Va localization in the major endocrine organs of rat.