Exposure to leucine induces oxidative stress in the brain of zebrafish.

Maple Syrup Urine Disease (MSUD) is an autosomal recessive inherited disorder caused by a deficiency in the activity of the branched-chain alpha-ketoacid dehydrogenase complex leading to the accumulation of branched-chain amino acids (BCAA) leucine, isoleucine, and valine and their respective branched-chain α-ketoacids and corresponding hydroxy acids. Considering that Danio rerio, known as zebrafish, has been widely used as an experimental model in several research areas because it has favorable characteristics that complement other experimental models, this study aimed to evaluate oxidative stress parameters in zebrafish exposed to high levels of leucine (2 mM and 5 mM), in a model similar of MSUD. Twenty-four hours after exposure, the animals were euthanized, and the brain content dissected for analysis of oxidative stress parameters: thiobarbituric acid reactive substances (TBARS), 2',7'-dichlorofluorescein oxidation assay (DCF); content of sulfhydryl, and superoxide dismutase (SOD) and catalase (CAT) activities. Animals exposed to 2 mM and 5 mM leucine showed an increase in the measurement of TBARS and decreased sulfhydryl content. There were no significant changes in DCF oxidation. In addition, animals exposed to 2 mM and 5 mM leucine were found to have decreased SOD activity and increased CAT activity. Based on these results, exposure of zebrafish to high doses of leucine can act as a promising animal model for MSUD, providing a better understanding of the toxicity profile of leucine exposure and its use in future investigations and strategies related to the pathophysiology of MSUD.

Acute exposure to leucine modifies behavioral parameters and cholinergic activity in zebrafish.

Maple Syrup Urine Disease (MSUD) is an autosomal recessive inherited disorder, caused by a deficiency on branched chain α-ketoacid dehydrogenase complex activity, resulting in accumulation of branched-chain amino acids (BCAA) (e.g. leucine). The treatment of MSDU patients increases survival time and quality of life. Thus, nowadays there are a crescent number of adolescents and adults with MSUD. Relevant studies have been reported behavioral alterations in these patients, i.e. high risk of chronic neuropsychiatric problems, such as attention deficit disorder, depression and anxiety. Moreover, MSUD is associated to neurotransmitters deficiency. Herein, we aimed to investigate whether the toxicity of leucine is associated to anxiety-like behavioral, using zebrafish acutely exposed to leucine as experimental model of MSUD. In addition, we evaluated the effects of high levels of leucine in the acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) activities, components of cholinergic neurotransmission system. Young zebrafish were exposed to 2 mM and 5 mM concentration of leucine for 24 h. After that, the animals were submitted to the Novel Tank test, having the brain collected to enzymatic determination. The exposure to both concentrations of leucine caused behavioral and brain cholinergic activity alterations in young zebrafish, indicating an anxiety-like behavior and cholinergic dysfunction. Therefore, this animal could be considered a promising organism to study the BCAA neurotoxic effects, which could help to a better comprehension of the behavioral and neurochemical alterations present in patients with MSUD.

Dominant/non-dominant support limb kinematics and approach run parameters in futsal kicking of stationary and rolling ball.

BACKGROUND: Task constraints and players' asymmetry influences on lower extremity (i.e. kicking limb) kinematics during futsal instep kicking. However, support limb behavior when shooting in a futsal context was not previously investigated, and its potential role on such discrepant motor outputs is still unclear. Thus, the study aimed to compare kinematic features of the support limb and approach run between kicking a stationary and a rolling ball using dominant and non-dominant limbs. METHODS: Ten futsal players participated (21.88±2.86 years-old, 73.66±4.17 kg and 1.75±0.04 m) and performed kicks (five per limb per condition) with the dominant and non-dominant limbs in stationary and rolling ball conditions. Kinematic analysis comprised determination of support limb angular joint (hip, knee and ankle) displacement and velocity, approach run distance, angle, linear velocity, step length and width, support foot-to-ball distance, ball velocity (120 Hz) and accuracy (60 Hz). RESULTS: Hip adjustments (greater extension) in the support limb when kicking a rolling ball contributed in maintaining similar performance (e.g., ball velocity) to kicking a stationary ball, compensating for the lower approach run velocity and longer support foot to ball distance. Kicking with the non-dominant limb demonstrated a lower approach run velocity and the non-dominant support limb presented different angular motion compared to the dominant support limb in hip (< internal rotation), knee (< flexion), and ankle joints (< plantar flexion), being harmful to performance in both kicking stationary and rolling balls. CONCLUSIONS: Kicking a stationary and rolling ball presented similar performance, but compared to the dominant side, futsal instep kicks performed with the non-dominant support limb induces lower approach run velocity and inefficient angular joint motion, either harmful to performance output.

Paraconsistents artificial neural networks applied to the study of mutational patterns of the F subtype of the viral strains of HIV-1 to antiretroviral therapy.

The high variability of HIV-1 as well as the lack of efficient repair mechanisms during the stages of viral replication, contribute to the rapid emergence of HIV-1 strains resistant to antiretroviral drugs. The selective pressure exerted by the drug leads to fixation of mutations capable of imparting varying degrees of resistance. The presence of these mutations is one of the most important factors in the failure of therapeutic response to medications. Thus, it is of critical to understand the resistance patterns and mechanisms associated with them, allowing the choice of an appropriate therapeutic scheme, which considers the frequency, and other characteristics of mutations. Utilizing Paraconsistents Artificial Neural Networks, seated in Paraconsistent Annotated Logic Et which has the capability of measuring uncertainties and inconsistencies, we have achieved levels of agreement above 90% when compared to the methodology proposed with the current methodology used to classify HIV-1 subtypes. The results demonstrate that Paraconsistents Artificial Neural Networks can serve as a promising tool of analysis.

A recombinant protein based on Trypanosoma cruzi P21 enhances phagocytosis.

BACKGROUND: P21 is a secreted protein expressed in all developmental stages of Trypanosoma cruzi. The aim of this study was to determine the effect of the recombinant protein based on P21 (P21-His(6)) on inflammatory macrophages during phagocytosis. FINDINGS: Our results showed that P21-His(6) acts as a phagocytosis inducer by binding to CXCR4 chemokine receptor and activating actin polymerization in a way dependent onthe PI3-kinase signaling pathway. CONCLUSIONS: Thus, our results shed light on the notion that native P21 is a component related to T. cruzi evasion from the immune response and that CXCR4 may be involved in phagocytosis. P21-His(6) represents an important experimental control tool to study phagocytosis signaling pathways of different intracellular parasites and particles.