Critical test of the activity of tetramisole phosphate on gastrointestinal helminths of sheep

The phosphate sale of tetramizol assayed in naturally infested sheep by subcutaneous infection at the dosis of 8,66 mg/kg revealed very high efficiency against strongylid gastro-intestinal nematodes; its efficiency was comparable that found by several authors for the hydrochloride and cyclamate salts of the same drug, also by subcutaneious injection, at the dosis of 10 mg/kg. In what concerns helminths belonging to the genera Strongyloides and Capillaria our results were not conclusive enough.     

Establishment and in vitro morphogenesis of sapucaia explants (Lecythidaceae)

Lecythis pisonis Cambess, popularly known as sapucaia, has great economic and socio-environmental potential. The objective of this study was to evaluate the establishment and in vitro morphogenesis of L. pisonis under the effect of disinfecting agents, plant growth regulators, and thermal stress. The study was divided into three experiments: (i) development of the disinfection protocol by testing different concentrations and times of exposure to sodium hypochlorite (NaOCl) and different concentrations and methods of amoxicillin application, (ii) in vitro budding induction by testing different concentrations of 6-benzylaminopurine (BAP) or kinetin (KIN) supplemented to Woody Plant Medium (WPM) and Murashige and Skoog (MS) culture media, and (iii) in vitro formation from plantlets by analyzing different concentrations of indole-3-butyric acid (IBA) with different exposure times to a thermal stress of 40°C. The disinfection of stem segments was effective using 3% NaOCl and 3.0 g L⁻¹ amoxicillin solution. MS culture medium supplemented with 0.25 mg L⁻¹ BAP induced more shoots in vitro. One milligram per liter IBA promoted greater rooting in vitro, and it is not necessary for thermal stress tolerance.

     

Potent Anti-Candida Fraction Isolated from Capsicum chinense Fruits Contains an Antimicrobial Peptide That is Similar to Plant Defensin and is Able to Inhibit the Activity of Different α-Amylase Enzymes

Antimicrobial peptides (AMPs) are molecules present in several life forms, possess broad-spectrum of inhibitory activity against pathogenic microorganisms, and are a promising alternative to combat the multidrug resistant pathogens. The aim of this work was to identify and characterize AMPs from Capsicum chinense fruits and to evaluate their inhibitory activities against yeasts of the genus Candida and α-amylases. Initially, after protein extraction from fruits, the extract was submitted to anion exchange chromatography resulting two fractions. Fraction D1 was further fractionated by molecular exclusion chromatography, and three fractions were obtained. These fractions showed low molecular mass peptides, and in fraction F3, only two protein bands of approximately 6.5 kDa were observed. Through mass spectrometry, we identified that the lowest molecular mass protein band of fraction F3 showed similarity with AMPs from plant defensin family. We named this peptide CcDef3 (Capsicum chinense defensin 3). The antifungal activity of these fractions was analyzed against yeasts of the genus Candida. At 200 μg/mL, fraction F1 inhibited the growth of C. tropicalis by 26%, fraction F2 inhibited 35% of the growth of C. buinensis, and fraction F3 inhibited all tested yeasts, exhibiting greater inhibition activity on the growth of the yeast C. albicans (86%) followed by C. buinensis (69%) and C. tropicalis (21%). Fractions F1 and F2 promoted membrane permeabilization of all tested yeasts and increased the endogenous induction of reactive oxygen species (ROS) in C. buinensis and C. tropicalis, respectively. We also observed that fraction F3 at a concentration of 50 µg/mL inhibited the α-amylase activities of Tenebrio molitor larvae by 96% and human salivary by 100%. Thus, our results show that fraction F3, which contains CcDef3, is a very promising protein fraction because it has antifungal potential and is able to inhibit the activity of different α-amylase enzymes.

     

Molecular dating for phylogenies containing a mix of populations and species by using Bayesian and RelTime approaches

Simultaneous molecular dating of population and species divergences is essential in many biological investigations, including phylogeography, phylodynamics and species delimitation studies. In these investigations, multiple sequence alignments consist of both intra‐ and interspecies samples (mixed samples). As a result, the phylogenetic trees contain interspecies, interpopulation and within‐population divergences. Bayesian relaxed clock methods are often employed in these analyses, but they assume the same tree prior for both inter‐ and intraspecies branching processes and require specification of a clock model for branch rates (independent vs. autocorrelated rates models). We evaluated the impact of a single tree prior on Bayesian divergence time estimates by analysing computer‐simulated data sets. We also examined the effect of the assumption of independence of evolutionary rate variation among branches when the branch rates are autocorrelated. Bayesian approach with coalescent tree priors generally produced excellent molecular dates and highest posterior densities with high coverage probabilities. We also evaluated the performance of a non‐Bayesian method, RelTime, which does not require the specification of a tree prior or a clock model. RelTime's performance was similar to that of the Bayesian approach, suggesting that it is also suitable to analyse data sets containing both populations and species variation when its computational efficiency is needed.     

Effects of hyperglycemia and aging on nuclear sirtuins and DNA damage of mouse hepatocytes

Hyperglycemia, like aging, induces chromatin remodeling in mouse hepatocytes in comparison to normoglycemia and younger age, respectively. Changes in glucose metabolism also affect the action and expression of sirtuins, promoting changes in chromatin conformation and dynamics. Here we investigate the abundance and activity of the nuclear sirtuins Sirt1, Sirt6, and Sirt7 in mouse hepatocytes in association with specific histone acetylation, DNA damage, and the activation of nucleolar organizing regions (NORs) in hyperglycemic nonobese diabetic (NOD) and old normoglycemic BALB/c mouse strains. Higher levels of Sirt1 and PGC-1α and increased expression of gluconeogenesis pathway genes are found in the hyperglycemic NOD mice. Increased Sirt6 abundance is found in the hyperglycemic NOD mice, which might increase DNA damage repair. With aging, lower Sirt1 abundance and activity, increased acetylated histone modifications and Sirt7 levels, and NOR methylation are found. Thus, whereas in normal aging cell metabolism is reduced, in the diabetic mice a compensatory mechanism may elevate Sirt1 and Sirt6 levels, increasing gluconeogenesis and DNA repair from the oxidative damage caused by hyperglycemia. Therefore understanding the regulation of epigenetic factors in diabetes and aging is crucial for the development of new therapeutic approaches that could prevent diseases and improve quality of life.