Toxicidade e repelência de extratos de plantas da caatinga sobre Tetranychus bastosi Tutler, Baker & Sales (Acari: Tetranychidae) em pinhão-manso / Toxicity and repellency of caatinga plant extracts on the Tetranychus bastosi Tutler, Baker & Sales in physic nut

RESUMO O objetivo deste trabalho foi avaliar o efeito repelente e a toxicidade dos extratos aquosos de Myracrodruon urundeuva Fr. All (Anacardiaceae), Croton blanchetianus Baill (Euphorbiaceae) e Ziziphus joazeiro Mart. (Rhamnaceae,) sobre o ácaro Tetranychusbastosi Tutler, Baker & Sales associado à cultura do pinhão- manso Jatropha curcas L. Para cada extrato as concentrações utilizadas foram 0, 5%, 10%, 15%, 20% e 25%. Avaliou-se, em teste sem chance de escolha, a mortalidade de fêmeas adultas de T. bastosi submetidas às diferentes concentrações de cada extrato. O delineamento estatístico foi o inteiramente casualizado, com seis tratamentos (testemunha e concentrações dos extratos) e 10 repetições. Os dados foram submetidos à análise de regressão. Também foi avaliado o efeito repelente dos referidos extratos sobre T. bastosi, nas concentrações supracitadas. Foi calculado o índice de repelência, percentual de repelência, classificação e índice de segurança. Os dados de percentual de repelência de adultos no tratamento e testemunha foram analisados pelo teste T de Student a 5% de probabilidade. De uma forma geral os extratos demonstraram efeito tóxico para adultos de T. bastosi nas concentrações testadas. O extrato de Z. joazeiro apresentou as maiores taxas de mortalidade (90%) média dos indivíduos. No que se refere à repelência destes extratos, todos os tratamentos se mostraram repelentes para fêmeas de T. bastosi, classificados como tratamentos repelentes, exceto para a dosagem de 5% do extrato de M. unrundeuva.

ABSTRACT The aim of this study was to evaluate the repellent effect and toxicity of aqueous extracts of M. urundeuva All Br. (Anacardiaceae), Crotonblanchetianus Baill( Euphorbiaceae ) and Ziziphus joazeiro Mart. (Rhamnaceae) on the mite Tetranychus bastosi Tutler, Baker & Sales associated with Jatropha curcas. For each extract, the concentrations used were 0, 5%, 10 %, 15 %, 20% and 25%. It was evaluated, at a no-choice test, the mortality of adult females of T. bastosi submitted to different concentrations of each extract. The experimental design was completely randomized with six treatments (control and concentrations of the extracts) and 10 repetitions. The data were subjected to regression analysis. The repellent effect of the extracts over the T. bastosi, in the concentrations already mentioned was also evaluated. The repellency index, percentage repellency, classification and safety index were assessed. The data of percentage repellency of adults in treatment and control were analyzed by the T test Student a 5% probability. In general, the extracts showed toxic effect on adults of T. bastosi for the concentrations tested. The extract of Z. joazeiro indicated d the highest average mortality rates (90 %) of individuals. Regarding the repellency of these extracts, all treatments have proved to be repellants for the females of T. bastosiclassified as repellent treatment, except for the 5% dose of the extract of M. unrundeuva.

Characterization of copper transport in gill cells of a mangrove crab Ucides cordatus.

The branchial epithelium of crustaceans is exposed to the environment and is the first site affected by metal pollution. The aim of this work was to characterize copper (Cu) transport using a fluorescent dye, Phen Green, in gill cells of a hypo-hyper-regulator mangrove crab Ucides cordatus. The results showed that added extracellular CuCl2 (0, 0.025, 0.150, 0.275, 0.550 and 1.110 µM) showed typical Michaelis-Menten transport for Cu in anterior and posterior gill cells (Vmax for anterior and posterior gills: 0.41 ± 0.12 and 1.76 ± 0.27 intracellular Cu in µM × 22.10(4)cells(-1)× 300 s(-1) respectively and Km values: 0.44 ± 0.04 and 0.32 ± 0.13 µM, respectively). Intracellular Cu was significantly higher for posterior gill cells compared to anterior gill cells, suggesting differential accumulation for each gill type. Extracellular Ca at 20mM decreased cellular Cu transport for both anterior and posterior gill cells. Nifedipine and verapamil, calcium channel inhibitors from plasma membrane, decreased Cu transport and affected Km for both gills. These results could be due to a competition between Cu and Ca. Amiloride, a Na/Ca exchanger inhibitor, as well as bafilomycin, a proton pump inhibitor, caused a decrease of intracellular Cu compared to control. Ouabain and KB-R 7943, acting on Na homeostasis, similarly decreased intracellular Cu in both gill cells. Besides that, gill cells exposed to ATP and Cu simultaneously, showed an increase in intracellular copper, which was inhibited by vanadate, an inhibitor of P-type ATPase. These results suggest either the presence of a Cu-ATPase in crab gill cells, responsible for Cu influx, or the effect of a change in electrochemical membrane potential that could also drive Cu to the gill cell interior. Caffeine increased intracellular Cu, suggesting that intracellular Ca could be affecting Cu uptake. Overall the results show that copper uptake in gill cells of crabs is regulated by intracellular Ca, Ca channels and by Na exchangers. This is the first report of Cu transport characterization in whole gill cells of crabs.

65Zn2+ transport by isolated gill epithelial cells of the American lobster, Homarus americanus.

Gills are the first site of impact by metal ions in contaminated waters. Work on whole gill cells and metal uptake has not been reported before in crustaceans. In this study, gill filaments of the American lobster, Homarus americanus, were dissociated in physiological saline and separated into several cell types on a 30, 40, 50, and 80% sucrose gradient. Cells from each sucrose solution were separately resuspended in physiological saline and incubated in 65Zn2+ in order to assess the nature of metal uptake by each cell type. Characteristics of zinc accumulation by each kind of cell were investigated in the presence and absence of 10 mM calcium, variable NaCl concentrations and pH values, and 100 muM verapamil, nifedipine, and the calcium ionophore A23187. 65Zn2+ influxes were hyperbolic functions of zinc concentration (1-1,000 microM) and followed Michaelis-Menten kinetics. Calcium reduced both apparent zinc binding affinity (K (m)) and maximal transport velocity (J (max)) for 30% sucrose cells, but doubled the apparent maximal transport velocity for 80% sucrose cells. Results suggest that calcium, sodium, and protons enter gill epithelial cells by an endogenous broad-specificity cation channel and trans-stimulate metal uptake by a plasma membrane carrier system. Differences in zinc transport observed between gill epithelial cell types appear related to apparent affinity differences of the transporters in each kind of cell. Low affinity cells from 30% sucrose were inhibited by calcium, while high affinity cells from 80% sucrose were stimulated. 65Zn2+ transport was also studied by isolated, intact, gill filament tips. These intact gill fragments generally displayed the same transport properties as did cells from 80% sucrose and provided support for metal uptake processes being an apical phenomenon. A working model for zinc transport by lobster gill cells is presented.

Dietary copper absorption and excretion in three semi-terrestrial grapsoid crabs with different levels of terrestrial adaptation.

Three species of phylogenetically related semi-terrestrial crabs (Superfamily Grapsoidea--Sesarma rectum, Goniopsis cruentata and Neohelice granulata (formerly: Chasmagnathus granulatus) with different degrees of terrestriality were studied to quantify the accumulation of copper (Cu) in hemolymph, gills, hepatopancreas and antennal gland, and its excretion through the faeces. These crabs were fed for 15 days practical diets containing 0 (A), 0.5 (B), 1.0 (C), and 1.5% (D) of added CuCl2 (corresponding to 0, 0.2, 0.5 and 0.7% of Cu2+, respectively). The amount of food ingested was directly proportional to the degree of terrestriality: S. rectum, the most terrestrial species, ate around 2-3 times more than the other crabs, whereas G. cruentata ate 1.5-2 times more than N. granulata, the least terrestrial. The amount of Cu excreted in the feces was proportional to Cu ingestion, and was 76.8% and 64.2% higher for Sesarma fed diet D compared to G. cruentata and N. granulata, respectively. Sesarma also displayed higher Cu concentration in the haemolymph, gills and antennal glands, but not in the hepatopancreas. A detoxifying mechanism followed by elimination was probably present at this last organ, preventing Cu accumulation. More terrestrial crabs, such as Sesarma, may accumulate more Cu in hemolymph and tissues, showing a correlation between metal accumulation and increased terrestriality. In this aspect, contaminated feed sources with Cu may have more impact in conservation of terrestrial crabs.