Evaluation of the efficiency of entomopathogenic nematodes exposed to different temperatures of vinasse in the control of Stomoxys calcitrans (Linnaeus, 1758) (Diptera: Muscidae).

The sugarcane industry generates byproducts that contribute to the proliferation of Stomoxys calcitrans. An analysis was carried out to verify the efficacy of Heterorhabditis bacteriophora HP88 and H. baujardi LPP7 at different vinasse temperatures to control S. calcitrans larvae. Ten fly larvae were deposited in plastic containers containing four mL of 50% vinasse. Each treatment consisted of 300 EPN/larvae of H. bacteriophora added to the containers and heated at temperatures of 25, 28, 31, 34, 37 and 40 °C. The same treatments were performed using H. baujardi. The treatments were carried out in a BOD incubator at 25 ± 1 °C and 70 ± 10% RH, and each treatment was replicated six times. The treated groups, controls and temperatures showed no statistical differences in terms of larval mortality rate (P=0.8573), percentage of dead pupae (P=0.1782) and adult emergence (P=0.4386). Larval mortality rates of 30% and 14.17% were achieved with H. bacteriophora and H. baujardi, respectively, while the control groups presented 3.89% with H. bacteriophora and 8.61% with H. baujardi. From the standpoint of temperatures, significant differences were found only at 37 and 40 °C for H. baujardi. The highest pupal mortality achieved with H. bacteriophora was 34.17% at 31 °C, while that reached with H. baujardi at 37 °C was 40%. The groups containing H. bacteriophora caused lower adult emergence rates at temperatures of 25, 28, 31 and 34 °C, while H. baujardi caused its lowest emergence rates at 37 and 40 °C. It is concluded that infection occurs in the immature stages of S. calcitrans by EPN when added to 50% vinasse solution at different temperatures and that nematodes caused negative effects on the emergence of fly larvae at varying temperatures.

A indústria da cana-de-açúcar gera subprodutos que ajudam na proliferação de Stomoxys calcitrans. Uma análise foi realizada para verificar a eficiência de Heterorhabditis bacteriophora HP88 e H. baujardi LPP7 em diferentes temperaturas de vinhaça no controle de larvas de S. calcitrans. Dez larvas da mosca foram depositadas em recipientes plásticos contendo quatro mL de vinhoto à 50%. Em cada tratamento adicionou-se 300 NEP/larva de H. bacteriophora, aquecidos nas temperaturas de 25, 28, 31, 34, 37 e 40 °C. Os mesmos tratamentos foram realizados utilizando e H. baujardi. Os tratamentos foram realizados e mantidos em câmara climatizada a 25 ± 1 °C e 70 ± 10% UR, foram realizadas seis repetições para cada tratamento. Não houve diferença estatística entre os grupos tratados, controles e temperaturas para taxa de mortalidade de larval (P=0,8573), percentual de pupas mortas (P=0,1782) e emergência de adultos (P=0,4386). Foram observadas taxas de mortalidade larval de 30% e 14,17% para H. bacteriophora e H. baujardi, respectivamente, enquanto os grupos controles apresentaram 3,89% no H. bacteriophora e 8,61% H. baujardi. Na avaliação das temperaturas, foram observadas diferenças significativas apenas nas temperaturas 37 e 40 °C de H. baujardi. A maior mortalidade pupal observada para H. bacteriophora foi de 34,17% quando em 31 °C, já para H. baujardi na temperatura de 37 °C apresentou 40% de mortalidade. Houve menor emergência de adultos nas temperaturas de 25, 28, 31 e 34 °C nos grupos com H. bacteriophora, já H. baujardi causou as menores taxas de emergência quando em 37 e 40 °C. Conclui-se que ocorre infecção nos estágios imaturos de S. calcitrans por NEP quando adicionados à solução de vinhoto a 50% em diferentes temperaturas e que os nematoides causaram efeitos negativos na emergência da mosca em temperaturas variadas.

Evaluation of the efficacy of entomopathogenic nematodes on Ctenocephalides felis felis larvae (Siphonaptera: Pulicidae).

Ctenocephalides felis felis is a relevant and widely distributed ectoparasite that acts as a vector of disease-causing pathogens. Moreover, it is responsible for economic losses due the use of harmful chemicals to the environment and that favor the emergence of insecticide-resistant populations. Research on entomopathogenic nematodes may open up an alternative route to the insect chemical control. The present study aimed to evaluate the killing efficacy of Heterorhabditis bacteriophora (HP88) against C. felis larvae in 400 µL, 600 µL and 1000 µL of suspension containing 120, 160 and 200 infective juveniles/larva and 600 µL of suspension containing the same concentrations of Heterorhabditis indica (LPP30), divided into two groups (absence and presence of diet) and a control group with three replications containing only distilled water. In the bioassay with H. bacteriophora, the groups in 600 µL of suspension showed higher mortality rates than those in the other tested volumes, which were above 80% at all concentrations. On the other hand, H. indica achieved mortality rates above 70% at all concentrations used. Results indicate that flea larvae are susceptible to in vitro infection by H. bacteriophora and H. indica.

Assessment of infection of Stomoxys calcitrans larvae by entomopathogenic nematodes Heterorhabditis amazonensis NEPT11.

This study aimed to evaluate the virulence of Heterorhabditis amazonenses NEPT11 against larvae of Stomoxys calcitrans. Groups of 10 third-instar fly larvae were deposited in Petri dishes, to which were added 50, 100 and 200 EPNs/larva in 4ml of distilled water. The volume of the control group was the same as the treated group, but without EPNs. Larval mortality was observed daily, until larvae died or adults emerged. The Petri dishes were kept on laboratory shelves at 27 ± 1 °C and 70 ± 10% RH. The experiment was replicated six times. A regression analysis revealed quadratic behavior with increasing concentrations, indicating that the concentration of 200 EPNs/larva (48%) was the most efficient among the tested concentrations, while concentrations of 50 and 100 EPNs/larva killed 26.6 and 40% of larvae, respectively. In general, none of the treatments resulted in a mortality rate of more than 50%, but all the treated groups exhibited a higher mortality than that of the control group. It is concluded that the EPN H. amazonensis NEPT11 shows a promising potential to control third-instar larvae of S. calcitrans. However, further studies are needed in different situations to better understand the activity of this organism against the immature stages of the stable fly.

Este estudo teve como objetivo avaliar a ação do NEP Heterorhabditis amazonenses NEPT11 frente larvas de S. calcitrans. Grupos de 10 larvas de terceiro instar da mosca foram depositados em placas de Petri, em seguida, adicionou-se 50, 100, 200, 300 e 400 NEPs/larva em 4ml de água destilada. O volume do grupo controle foi o mesmo dos tratados, porém sem NEPs. A mortalidade das larvas foi observada diariamente, até a morte das larvas ou emergência de adultos. As placas foram mantidas em estantes de laboratório a 27 ± 1 °C e 70 ± 10% UR. O experimento teve seis repetições. Por meio da análise de regressão, foi observado comportamento quadrático com o aumento das concentrações, sendo a concentração de 200 NEPs/larva (48%) a de maior eficiência entre as concentrações testadas, já as concentrações de 50 e 100 NEPs/larva mataram 26,6 e 40% das larvas, respectivamente. De modo geral, nenhum tratamento proporcionou mortalidade superior a 50%, todavia, todos os grupos tratados apresentaram mortalidade superior à observada no controle. Conclui-se que H. amazonenses NEPT11 mostrou-se promissor no controle de larvas de terceiro instar de S. calcitrans, porém mais estudos devem ser feitos para o melhor entendimento da ação deste organismo frente aos estágios imaturos da mosca-dos-estábulos.

Evaluation of the efficacy of entomopathogenic nematodes on Ctenocephalides felis felis larvae (Siphonaptera: Pulicidae) / Avaliação da eficácia de nematoides entomopatogênicos sobre larvas de Ctenocephalides felis felis (Siphonaptera: Pulicidae)

Abstract Ctenocephalides felis felis is a relevant and widely distributed ectoparasite that acts as a vector of disease-causing pathogens. Moreover, it is responsible for economic losses due the use of harmful chemicals to the environment and that favor the emergence of insecticide-resistant populations. Research on entomopathogenic nematodes may open up an alternative route to the insect chemical control. The present study aimed to evaluate the killing efficacy of Heterorhabditis bacteriophora (HP88) against C. felis larvae in 400 μL, 600 μL and 1000 μL of suspension containing 120, 160 and 200 infective juveniles/larva and 600 μL of suspension containing the same concentrations of Heterorhabditis indica (LPP30), divided into two groups (absence and presence of diet) and a control group with three replications containing only distilled water. In the bioassay with H. bacteriophora, the groups in 600 μL of suspension showed higher mortality rates than those in the other tested volumes, which were above 80% at all concentrations. On the other hand, H. indica achieved mortality rates above 70% at all concentrations used. Results indicate that flea larvae are susceptible to in vitro infection by H. bacteriophora and H. indica.

Resumo Ctenocephalides felis felis é um ectoparasito de relevância, ampla distribuição geográfica, vetor de patógenos causadores de doenças e responsável por perdas econômicas relacionadas ao uso de produtos químicos que causam impacto ambiental e aparecimento de populações resistentes. Pesquisas com nematoides entomopatogênicos podem ser uma alternativa ao controle químico desse inseto. O presente estudo objetivou avaliar a eficácia de Heterorhabiditis bacteriophora (HP88) em larvas de C. felis em 400 μL, 600 μL e 1000 μL de suspensão contendo 120, 160 e 200 juvenis infectantes/larva e 600 μL de suspensão contendo as mesmas concentrações de Heterorhabditis indica (LPP30), divididos em dois grupos (ausência e presença de dieta) e grupo controle com três repetições contendo apenas com água destilada. No bioensaio com H. bacteriophora observou-se que os grupos com 600 μL de suspensão apresentaram melhores percentuais de mortalidade em relação aos outros volumes testados, sendo estas acima de 80% para as três concentrações. Já H. indica apresentou percentuais de mortalidades acima de 70% para as três concentrações utilizadas. Os resultados indicam que as larvas de pulga são suscetíveis a infecção in vitro por H. bacteriophora e H. indica.

Evaluation of the effect of Heterorhabditis bacteriophora (HP88) on Stomoxys calcitrans (Linnaeus, 1758) larvae (Diptera: Muscidae) in sugarcane bagasse ash.

The purpose of this study was to evaluate the effect of the EPN Heterorhabditis bacteriophora HP88 on Stmoxys. calcitrans larvae in sugarcane bagasse ash. Groups of 10 stable fly larvae were placed in Petri dishes containing filter paper and bagasse ash. Concentrations of 50, 150 and 250 EPNs/larva of S. calcitrans in four milliliters of distilled water were added to each plate. In the control group contained only distilled water, without EPNs. The bioassay had three replications and was maintained at 27 ± 1°C and 70-80% relative humidity. It was observed that mortality rate in all treated groups was significantly higher than in the control group (26,6%). The mortality rate in the presence of 50 EPNs/larva (46,6%) was lower than in 150 EPNs/larva (76,3%), which in turn was lower than 250 EPNs/larva group (93,3%). It was verified by analysis of variance and regression that there was a linear pattern of mortality, that is, the higher the EPNs/larva concentration, the higher the larval mortality. It was concluded that EPN H. bacteriophora HP88 was capable of infecting and causing mortality of stable fly larvae in sugarcane bagasse ash.

O objetivo deste estudo foi avaliar o efeito do NEP Heterorhabditis bacteriophora HP88 sobre larvas de Stomoxys calcitrans em cinzas de bagaço de cana-de-açúcar. Grupos de 10 larvas da mosca dos estábulos foram depositadas em placas de Petri contendo papel filtro e cinzas. Foram adicionadas concentrações de 50, 150 e 250 NEPs/larva de S. calcitrans em cada placa. No grupo controle não havia NEPs, somente água destilada. O bioensaio teve três repetições e foi mantido em 27 ± 1°C e 70-80% de umidade relativa. Observou-se que a mortalidade em todos os grupos tratados foi significativamente superior à do grupo controle (26,6%). A taxa de mortalidade na presença de 50 NEPs/larva (46,6%) foi menor do que em 150 NEPs/larva (76,3%), que por sua vez foi menor do que no grupo 250 NEPs/larva (93,3%). Verificou-se pela análise de variância e de regressão que houve um padrão linear de mortalidade, ou seja, quanto maior a concentração de NEPs/larva, maior a mortalidade larval. Conclui-se que o NEP H. bacteriophora HP88 foi capaz de infectar e causar mortalidade das larvas da mosca dos estábulos em cinza de bagaço de cana e que aparentemente este subproduto não interfere negativamente na ação deste NEP.

The use of apocynin inhibits osteoclastogenesis.

Reactive oxygen species (ROS) are produced by NADPH oxidase (NOX), an enzyme that reduces oxygen by using NADPH as a substrate. Apocynin (APO) is a catechol that is used as a NOX inhibitor, and N-acetyl-cysteine ​​(NAC) can reduce intracellular ROS levels. In this work, the effect of APO and NAC on osteoclast formation were evaluated. APO and NAC significantly decreased the number of tartrate-resistant acid phosphatase (TRAP)-positive cells and the osteoclast area. We analyzed bone-marrow derived monocyte-macrophages (BMMs) that differentiated into osteoclasts after RANKL stimulation. Stimulation was associated with either APO or NAC treatment and osteoclastogenesis marker expression, including NFATc1, MMP-9, and DC-STAMP, was evaluated. APO decreased the intracellular calcium concentration by calcium channels other than ITPR1 and TPC2. On the other hand, APO reduced Tnfrsf11a (RANK) expression and did not alter Fam102a (EEIG1) expression. Therefore, our results demonstrate that APO inhibits osteoclastogenesis by the RANK-RANKL-related signaling pathways, decreases osteoclast markers, and reduces intracellular calcium concentration.

Controlling the cytotoxicity of CdSe magic-sized quantum dots as a function of surface defect density.

Quantum dots are potentially very useful as fluorescent probes in biological systems. However, they are inherently cytotoxic because of their constituents. We controlled the cytotoxicity of CdSe magic-sized quantum dots (MSQDs) as a function of surface defect density by altering selenium (Se) concentration during synthesis. Higher Se concentrations reduced the cytotoxicity of the CdSe MSQDs and diminished mRNA expression of methallothionein because of the low cadmium ions (Cd(2+)) concentration adsorbed on the surface of the MSQDs. These results agree with luminescence spectra, which show that higher Se concentrations decrease the density of surface defects. Therefore, our results describe for the first time a simple way of controlling the cytotoxicity of CdSe MSQDs and making them safer to use as fluorescence probes in biological systems.