RESUMEN
RESUMO O controle de fitonematóides é uma tarefa difícil. A alta infestação de nematoides no solo obriga os produtores a usarem doses mais elevadas de nematicidas, ou ainda, a aumentarem a freqüência das aplicações, geralmente no solo, ocasionando maior potencial de dano ao homem e ao ambiente. Além disso, nematicidas convencionais vêm sofrendo grandes restrições de uso em muitos países. Desse modo, a busca de novas medidas de controle de fitonematóides é uma prioridade da agricultura sustentável. Desta forma, objetivou-se estudar o efeito de óleos essenciais de Lippia Alba, na mortalidade de juvenis pré-parasitas do segundo estádio de Meloidogyne incognita. O ensaio foi montado em delineamento inteiramente casualizado, com 4 repetições, em esquema fatorial 3×4 (3 quimiotipos x 4 concentrações) empregando-se três diferentes quimiotipos de L. Alba (I, II, III) nas concentrações de 0, 100, 500 e 1000 ppm, coletados em diferentes horas do dia (7, 9, 13, 16 e 19h). Os dados coletados (% de mortalidade) foram submetidos à análise de variância e os valores médios comparados por meio do teste de Tukey. Foi possível concluir que Lippia alba contém, em seu óleo essencial, compostos com efeitos significativos na mortalidade de juvenis de segundo estádio (J2) de M. incognita. Dessa forma, é importante destacar que o acentuado efeito nematicida do óleo essencial de L. alba sugere a possibilidade de seu uso no controle de M. incognita.
ABSTRACT The control of nematodes is difficult. The high infestation of nematodes in the soil requires the producers use higher doses of nematicides, increasing the frequency of applications, usually in soil, causing negative effects to humans and the environment. Furthermore, conventional nematicides have suffered great use restrictions in many countries. Thus, the search for new measures to control nematodes is a priority of sustainable agriculture. Thus, the objective of this study was available the effect of essential oils from Lippia Alba against Meloidogyne incognita. The experiment was conducted in a completely randomized design with four replications in a factorial 3x4 (3 chemotypes and 4 concentrations) using three different chemotypes of L. Alba (I, II, III) at concentrations of 0, 100, 500 and 1000 ppm, collected in different times of day (7 AM, 9 AM, 1 PM, 4 PM e 7 PM). The data collected (% mortality) were subjected to analysis of variance and mean values were compared using the Tukey test. It was able to conclude that L. alba contains in its essential oil, compounds with significant effects on mortality of M. incognita. Thus, it is important to note that the greatest nematicide effect of essential oil of L. alba suggests the possibility of its use to control M. incognita.
Asunto(s)
Aceites Volátiles/farmacología , Lippia , Suelo/clasificación , Nematodos/clasificación , Antinematodos/análisisRESUMEN
The leukemia cell line HL60 is widely used in studies of the cell cycle, apoptosis, and adhesion mechanisms in cancer cells. We conducted a focused cytogenetic study in an HL60 cell line, by analyzing GTG-banded chromosomes before and after treatment with pisosterol (at 0.5, 1.0, and 1.8 microg/ml), a triterpene isolated from Pisolithus tinctorius, a fungus collected in the Northeast of Brazil. Before treatment, 99% of the cells showed the homogeneously staining region (HSR) 8q24 aberration. After treatment with 1.8 microg/ml pisosterol, 90% of the analyzed cells lacked this aberration. We further performed a pulse test, in which the cells treated with pisosterol (0.5, 1.0, and 1.8 microg/ml) were washed and re-incubated in the absence of pisosterol. Only 30% of the analyzed cells lacked the HSR 8q24 aberration, suggesting that pisosterol probably blocks the cells with HSRs at interphase. No effects were detected at lower concentrations. At the highest concentration examined (1.8 microg/ml), pisosterol also inhibited cell growth, but this effect was not observed in the pulse test, reinforcing our hypothesis that, at the concentrations tested, pisosterol probably does not induce cell death in the HL60 line. The results found for pisosterol were compared with those for doxorubicin. Cells that do not show a high degree of gene amplification (HSRs and double-minute chromosomes) have a less aggressive and invasive behavior and are easy targets for chemotherapy. Therefore, further studies are needed to examine the use of pisosterol in combination with conventional anti-cancer therapy.