Cytotoxic effects of essential oils from three Lippia gracilis Schauer genotypes on HeLa, B16, and MCF-7 cells and normal human fibroblasts.

This study aimed to evaluate the chemical composition of the essential oils from three genotypes of Lippia gracilis Schauer (Verbenaceae) and investigate the cytotoxic activities of these oils. Essential oils were extracted from the leaves using a Clevenger-type apparatus, and chemical analysis was performed using a gas chromatograph coupled to a mass spectrometer and flame ionization detector. 3T3, MRC5, B16, HeLa, and MCF-7 cell lines were used to study the in vitro cytotoxicity of the essential oils, and the level of cell death was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test with three replicates. The cytotoxic activity was expressed as the concentration that inhibited 50% of cell growth. The main compound in the essential oil of LGRA-106 was thymol (40.52%), while LGRA-109 and LGRA-201 contained 45.84 and 32.60% carvacrol, respectively, as their major compound. The essential oils of L. gracilis showed cytotoxic activity against both normal and tumor cells at concentrations below 100 µg/mL; this demonstrated the antitumor potential of these essential oils, which should be further investigated.

The effect of abiotic factors on the hatching of Moina micrura Kurz, 1874 (Crustacea: Cladocera) ephippial eggs.

The roles of some abiotic factors in controlling the hatching rates of Moina micrura ephippial eggs were investigated. Determination of optimum hatching conditions would be important in developing the use of this species as a food for fish larvae in aquaculture. Ephippia were exposed to different treatments in the laboratory, and monitored for hatching over a period of seven days. Optimum hatching conditions were: pH 5-9, temperature 25 degrees C, photoperiod eight or more hours light per day and light intensity equal to or greater than 850 lux. Differences in water ionic concentrations (from deionized water to 880 mg.L-1 of selected salts) had no effect.

The effect of abiotic factors on the hatching of Moina micrura Kurz, 1874 (Crustacea: Cladocera) ephippial eggs

The roles of some abiotic factors in controlling the hatching rates of Moina micrura ephippial eggs were investigated. Determination of optimum hatching conditions would be important in developing the use of this species as a food for fish larvae in aquaculture. Ephippia were exposed to different treatments in the laboratory, and monitored for hatching over a period of seven days. Optimum hatching conditions were: pH 5-9, temperature 25ºC, photoperiod eight or more hours light per day and light intensity equal to or greater than 850 lux. Differences in water ionic concentrations (from deionized water to 880 mg.L-1 of selected salts) had no effect

Biosynthesis of secondary metabolites in sugarcane

Este trabalho foi realizado com os objetivos de gerar uma coleçäo de genes relacionados ao metabolismo secundário da cana de açúcar e investigar o padräo de expressäo gênica de enzimas chaves reguladoras das principais vias biossintéticas ativas nos diferentes tipos de tecidos e situações de estresse físico-químico e biológico a que estäo submetidas plantas cultivadas em casas de vegetaçäo, campo ou in vitro. A estratégia de mineraçäo dos dados da database de sequências expressas de cana de açúcar, SUCEST, usando ferramentas de bioinformática, focalizou classes de compostos como isoprenóides e fenilpropanóides que comprovadamente desempenham um papel na resposta de plantas a variações ambientais. Foram identificados e caracterizados genes que codificam enzimas chaves para a síntese de terpenóides, como a sesquiterpeno ciclase (SC); (CHS) para síntese de flavonóides; isoflavona sintase (IFS) envolvida na biossíntese de isoflavonóides que desempenham importante papel na defesa de plantas e nodulaçäo de raízes; isoflavona redutases (IFR) enzimas chaves para a síntese de fenilpropanóide fitoalexinas, bem como enzimas relacionadas à síntese de precursores de lignina, como a enzima ácido caféico-O-metiltransferase. O efeito do estresse causado por bactérias como Herbaspirillum rubri e Gluconacetobacter diazotroficans também foi avaliado tendo sido constatada a induçäo da expressäo de chalcona sintase (CHS) em plântulas infectadas com esses agentes, sugerindo a ativaçäo da via de flavonóides em resposta a este estresse biológico. Esses resultados apontam para o fato de que as vias do metabolismo de isopropanóides e de fenilpropanóides em cana de açúcar säo ativadas de acordo com o estágio de desenvolvimento, especificidade de tecidos e em resposta a situações de estresse. Essas observações deveräo ser confirmadas por meio de experimentaçäo genética e bioquímica.