Rac1/WAVE2 and Cdc42/N-WASP Participation in Actin-Dependent Host Cell Invasion by Extracellular Amastigotes of Trypanosoma cruzi

This study evaluated the participation of host cell Rho-family GTPases and their effector proteins in the actin-dependent invasion by Trypanosoma cruzi extracellular amastigotes (EAs). We observed that all proteins were recruited and colocalized with actin at EA invasion sites in live or fixed cells. EA internalization was inhibited in cells depleted in Rac1, N-WASP, and WAVE2. Time-lapse experiments with Rac1, N-WASP and WAVE2 depleted cells revealed that EA internalization kinetics is delayed even though no differences were observed in the proportion of EA-induced actin recruitment in these groups. Overexpression of constitutively active constructs of Rac1 and RhoA altered the morphology of actin recruitments to EA invasion sites. Additionally, EA internalization was increased in cells overexpressing CA-Rac1 but inhibited in cells overexpressing CA-RhoA. WT-Cdc42 expression increased EA internalization, but curiously, CA-Cdc42 inhibited it. Altogether, these results corroborate the hypothesis of EA internalization in non-phagocytic cells by a phagocytosis-like mechanism and present Rac1 as the key Rho-family GTPase in this process.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e TecnologicoUniv Fed Sao Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, Sao Paulo, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, Sao Paulo, BrazilFAPESP: 2012/21335-8, 2011/51475-3CNPq: 302068/2016-3Web of Scienc

RELIABILITY OF A FLIGHT TIME MEASUREMENT INSTRUMENT DURING VERTICAL JUMP

Researchers and practitioners who evaluate performance of study participants, patients, athletes or other clients, should use tests with high reliability, because these are the only tests that can have high validity. The aim of this study was to determine the reliability of a contact mat (CM). For this, sixteen volunteers had carried out a series of three vertical jumps in the test and had repeated the same procedure one week later in the retest. The flight time was registered by CM and force plate (FP) simultaneously. The result of the Mann-Whitney test showed that did not have significant difference between the test and retest in two instruments, and the correlation values were high between test and retest and between the instruments. From these results, it is concluded that the tested CM is a reliable tool to measure the flight time of the vertical jump

ELECTROMYOGRAPHY DURING AQUATIC CYCLING IN DIFFERENT CADENCES: PILOT STUDY

The effects of cadence and load on lower limb muscles activities using electromyography (EMG) are well documented in cycling literature (Baum and Li, 2003). They reported that increase of cadence displayed a non significant reduction of the EMG for Biceps Femoris (BF) and Vastus Lateralis (VL); however, with an increased load there was an increase in the EMG in both muscles when used Monarch cycle ergometer. They attributed this reduction of the EMG in relation to cadence to increase of inertial influence on pedal force. The aim of this study is to verify influence of cadences (50 and 65rpm) on lower limb muscles activities (BF and VL) using aquatic cycle ergometry (ACE)

Os tipos de conhecimento e o perfil de treinadores das categorias de base do futebol brasileiro: Types of knowledge and profile of brazilian football categories coaches

O treinador tem diversas funções dentro de um clube que abrange o planejamento dos treinos até a gestão de pessoas, sendo de suma importância para o alcance do sucesso de um clube, enfrentando várias pressões neste ambiente, o que exige diferentes competências dentro e fora de campo. No futebol brasileiro, o treinador convive com uma cultura imediatista, que aumenta ainda mais a necessidade de constante capacitação. O objetivo é analisar e identificar fatores relacionados aos conhecimentos profissionais, interpessoais e intrapessoais de treinadores de categorias de base do futebol brasileiro. Participaram do estudo seis treinadores de categoria de base do futebol nacional masculino que responderam a um roteiro de entrevista semiestruturada, além de um teste de empatia. Os resultados indicam que o conhecimento profissional capacita os treinadores a aplicar a sua metodologia e ideias de jogo, enquanto o conhecimento interpessoal os auxilia na manutenção no clube e uma relação saudável com os envolvidos e, por fim, o conhecimento intrapessoal se torna necessário para avaliar o trabalho desenvolvido, além de se realizar uma autocritica e, consequentemente, melhorar o trabalho desenvolvido. Conclui-se que os três tipos de conhecimentos são imprescindíveis para o alcance do sucesso, conectando a teoria à prática, os tornando mais aptos a suportar as pressões da profissão e se manter no cargo

Análise da autoeficácia e perfeccionismo em árbitros de natação do Brasil

The study aimed to analyze perfectionism and self-efficacy levels in swimming’s referees from Brazil. The sample was composed by 150 referees, 72 male and 78 female, with at least one year of experience in official federation’s staff, 34 from state level, 66 national and 50 international. As instruments was utilized: identification form, General Perceived Self-efficacy Scale and Multidimensional Perfectionism Scale. Data were collected during competitions of official calendar from Brazilian Confederation of Aquatic Sports in 2011 and 2012. In statistical analysis were utilized the tests: Kolmogorov-Smirnov, Mann-Whitney, Kruskall-Wallis, Friedman and Spearman correlation coefficient, with p<0,05. It was observed that organization was the perfectionism characteristic that obtained the highest score, female referees showed higher levels of concern over mistakes, doubts about actions and negative perfectionism than male referees, besides, state-level referees showed higher levels of parental expectations, personal standards and positive perfectionism than national-level. It was concluded that swimming referees showed high levels of self-efficacy and organization; female referees had higher scores in concern over mistakes, doubts about actions and negative perfectionism; there is no correlation between self-efficacy and perfectionism in Brazilian swimming referees

EFEITO RESIDUAL DO MÉTODO FNP SOBRE O DESEMPENHO DE RESISTÊNCIA DE FORÇA NO SUPINO HORIZONTAL

Stretching done before resistance exercises can reduce the strength of stretched muscle. The objective was to measure the effect of the Proprioceptive Neuromuscular Facilitation (PNF) method on the strength resistance performance in bench press (BP). The number of maximum repetitions (nMR) and subjective perception of effort (SPE) in BP were evaluated in 18 healthy men (23.7±2.9years), in three situations: I) BP without previous stretching (control); II) FNP+BP performed after stretching (FNP+ BP); III) FNP+5 minutes of interval +BP (FNP+5’+BP). The value adopted for p was &lt;0.05. The nMR in FNP+BP situation was lower than control. There were no differences between the nMR of control situation and FNP+5’+BP, as well as between FNP+BP and FNP+5’+BP. Additionally, there was no difference in SPE in the situations evaluated. It is concluded that PNF stretching can reduce strength performance for up to five minutes when applied immediately before BP exercise.El estiramiento realizado antes de los ejercicios de fuerza puede reducir la fuerza del músculo estirado. El objetivo fue medir el efecto del método de Facilitación Neuromuscular Propioceptiva (PNF) sobre el desempeño de fuerza resistencia en el press de banca (PB). Se evaluó el número de repeticiones máximas (nRM) y la percepción subjetiva de esfuerzo (PSE) en 18 hombres sanos (23,7±2,9años), en tres situaciones: I) PB sin estiramiento previo (control); II) Estiramiento FNP+PB (FNP+SH); III) Estiramiento FNP+5 minutos +PB (FNP+5’+PB). El valor de p fue &lt;0,05. La nRM en la situación FNP+PB fue menor que en el control. No hubo diferencias entre el nRM de la situación de control y el FNP+5’+PB, así como entre FNP+PB y FNP+5’+PB. Además, no hubo diferencia en PSE. Se concluye que el estiramiento PNF puede reducir el rendimiento de la fuerza hasta por cinco minutos cuando se aplica inmediatamente antes del PB.O alongamento feito antes de exercícios resistidos pode reduzir a força do músculo alongado. Objetivou-se mensurar o efeito do método Facilitação Neuromuscular Proprioceptiva (FNP) sobre o desempenho de resistência de força no supino horizontal (SH). Avaliou-se o número de repetições máximas (nRM) e a percepção subjetiva do esforço (PSE) no SH, em 18 homens saudáveis (23,7±2,9anos), em três situações: I) SH sem alongamento prévio (controle); II) Alongamento FNP+SH após alongamento (FNP+SH); III) Alongamento FNP+5 minutos de intervalo +SH (FNP+5’+SH). O valor adotado para p foi &lt;0,05. O nRM na situação FNP+SH foi menor do que na controle. Não houve diferenças entre o nRM da situação controle e da FNP+5’+SH, assim como entre FNP+SH e FNP+ 5’+SH. Adicionalmente, não houve diferença na PSE nas situações avaliadas. Conclui-se que o alongamento FNP pode reduzir o desempenho de força por até cinco minutos quando aplicado imediatamente antes do exercício SH

Revestimento comestível antimicrobiano e aromático na conservação de abacaxi minimamente processado

The present research aimed to develop an edible coating incorporated with mint essential oil, evaluate its effectiveness in inhibiting in vitro microbial development, and improve both quality and shelf-life of fresh-cut pineapple. Mint essential oil-containing edible coatings showed in vitro antimicrobial efficiency against Escherichia coli and Salmonella Enteritidis. Titratable acidity, pH, and texture were not affected (P>0.05) by coating or storage time. Mass loss was not higher than 1.0% after the 6th day of storage. No effect of storage time and coating on total soluble solids was observed. Mint essential oil-containing coatings inhibited the growth of yeasts and molds in fresh-cut pineapple. Compared to uncoated and control-coated samples, mint essential oil-containing coatings lessened psychrotrophic bacteria counts throughout storage. Counts of thermotolerant coliforms were not higher than 3.0MPN·g-1 in all treatments, whereas no Salmonella sp. was detected during the 6-day storage. Mint essential oil provided a strong flavor to the fruit, as shown by sensory evaluations44611191125CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFINANCIADORA DE ESTUDOS E PROJETOS - FINEPFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE MINAS GERAIS - FAPEMIGSem informaçãoSem informaçãoSem informaçãoSem informaçãoO objetivo deste trabalho foi desenvolver um revestimento comestível incorporado com óleo essencial de hortelã, bem como avaliar sua eficiência antimicrobiana in vitro e em abacaxi minimamente processado. Revestimentos contendo óleo essencial de hortelã mostraram eficiência antimicrobiana in vitro contra Escherichia coli e Salmonella Enteritidis. O pH, a acidez titulável e a textura não foram afetadas (P>0.05) pelos tratamentos durante o armazenamento. A perda de massa dos abacaxis de todos os tratamentos não ultrapassou 1.0% após 6 dias de armazenamento. O tempo e os diferentes revestimentos não afetaram (P>0,05) o teor de sólidos solúveis totais dos abacaxis. Revestimentos contendo óleo essencial de hortelã foram capazes de inibir o crescimento de fungos e leveduras em abacaxi minimamente processado, quando comparado aos frutos sem revestimento e com revestimento controle. Frutos com revestimento contendo óleo essencial de hortelã apresentaram menor contagem de psicrotróficos no final do armazenamento. A contagem de coliformes termotolerantes foi menor que 3.0NMP·g-1 para todos os tratamentos e não foi detectada presença de Salmonella sp. durante o período de armazenamento. A presença de óleo essencial de hortelã conferiu forte sabor aos abacaxi

Amastigote Synapse: The Tricks of Trypanosoma cruzi Extracellular Amastigotes

To complete its life cycle within the mammalian host, Trypanosoma cruzi, the agent of Chagas’ disease, must enter cells. Trypomastigotes originating from the insect vector (metacyclic) or from infected cells (bloodstream/tissue culture-derived) are the classical infective forms of the parasite and enter mammalian cells in an actin-independent manner. By contrast, amastigotes originating from the premature rupture of infected cells or transformed from swimming trypomastigotes (designated extracellular amastigotes, EAs) require functional intact microfilaments to invade non-phagocytic host cells. Earlier work disclosed the key features of EA-HeLa cell interplay: actin-rich protrusions called ‘cups’ are formed at EA invasion sites on the host cell membrane that are also enriched in actin-binding proteins, integrins and extracellular matrix elements. In the past decades we described the participation of membrane components and secreted factors from EAs as well as the actin-regulating proteins of host cells involved in what we propose to be a phagocytic-like mechanism of parasite uptake. Thus, regarding this new perspective herein we present previously described EA-induced ‘cups’ as parasitic synapse since they can play a role beyond its architecture function. In this review, we focus on recent findings that shed light on the intricate interaction between extracellular amastigotes and non-phagocytic HeLa cells

Volume total e número de repetições máximas durante séries de treinamento resistido: método tradicional vs série agonista-antagonistado

OBJETIVO: Comparar volume total e número repetições máximas (nRM) que pode ser realizado nos exercícios rosca direta (RD) e tríceps na polia (TP), variando a ordem de execução, nos métodos tradicional (TRAD) e série pareada agonista-antagonista (SPAA). MÉTODOS: Doze indivíduos (22±3,5 anos) com experiência em treinamento resistido (TR), compareceram a 10 sessões com intervalo de 48 a 72 horas entre elas. Após avaliação antropométrica, três sessões de familiarização e realização de testes de uma repetição máxima (1-RM) e reprodutibilidade de 1-RM, foram realizados quatro protocolos experimentais para mensuração do nRM, utilizando 70% de 1-RM: TRAD1 (quatro séries no exercício RD + quatro séries no exercício TP); TRAD2 (quatro séries no exercício TP + quatro séries no exercício RD); SPAA1 (quatro séries no exercício RD e TP) e; SPAA2 (quatro séries no exercício TP e RD). Sob o método TRAD, foram implementados intervalos de 90 segundos entre todas séries realizadas; um intervalo de descanso de dois minutos foi implementado entre a conclusão da última série do primeiro exercício e a primeira série do segundo exercício (RD + TP ou TP + RD). Sob o método SPAA, nenhum intervalo foi implementado entre o primeiro e segundo exercício (RD e TP ou TP e RD); noventa segundos de intervalo de descanso foram implementados após conclusão do primeiro e do exercício subsequente.RESULTADOS: Não foram observadas diferenças no volume total e percepção subjetiva do esforço (PSE) entre os protocolos experimentais, enquanto foi verificado maior nRM no exercício TP em comparação com o RD em todos os protocolos utilizados.CONCLUSÃO: Na intensidade de 70% de 1-RM, o volume total não é influenciado pelo método de TR (TRAD ou SPAA) e pela ordem dos exercícios (RD e TP ou TP e RD). Adicionalmente, observou-se que o nRM parece ser influenciado pelo grupamento muscular utilizado.ABSTRACT. Total volume and maximum number of repetitions performed during resistance training sets: traditional versus agonist-antagonist set methods.OBJECTIVE: To compare the total volume and number of maximum repetitions (nMR) that can be performed in barbell curl (BC) and triceps pushdown (TP) exercises, varying order of execution, on traditional (TRAD) and agonist-antagonist paired set (AAPS) methods.METHODS: Twelve individuals (22±3.5 years) with experience in resistance training (RT), attended 10 sessions with an interval of 48 to 72 hours between them. After anthropometric evaluation, three familiarization sessions, one repetition maximum tests (1-RM) and reproducibility, four experimental protocols were performed to measure the total volume and nMR, using 70% of 1-RM: TRAD1 (four sets of exercise BC + four sets of exercise TP); TRAD2 (four sets of TP exercise + four sets of BC exercise); AAPS1 (four sets of exercise BC and TP) and; AAPS2 (four sets of exercise TP and BC). Under the TRAD method, 90-seconds rest intervals were implemented between all sets; two-minute rest interval between the completion the last set of first exercise and the first set of second exercise was implemented (BC + TP or TP + BC). Under the AAPS method, no interval was implemented between first and second exercise (BC and TP or TP and BC); a 90-seconds rest interval after the completion of the first and the subsequent exercise was implemented. RESULTS: There were no differences in total volume and rating of perceived exertion (RPE) between the experimental protocols, while a higher nMR was found in the TP exercise compared to the BC in all protocols used.CONCLUSION: It is concluded that in the intensity of 70% 1-RM, the total volume is not influenced by the TR method (TRAD or AAPS) and by the order of the exercises (BC and TP or TP and BC). Additionally, it was observed that the nMR seems to be influenced by the muscle group used