Ascorbate and glutathione contents in duckweed, Lemna minor, as biomarkers of the stress generated by copper, folpet and diuron

Glutathione and ascorbate are essential components of the general antioxidative strategy to overcome oxidative stress due to environmental constraints such as pollution. The variation of glutathione and ascorbate contents in duckweed (Lemna minor) was investigated after a 48 h exposure to copper, diuron and folpet under laboratory conditions in order to determine whether changes in their level could serve as suitable and early biomarkers of pollution. One could observe that diuron and folpet caused the glutathione level to increase, its redox status remaining unchanged, while copper led to a depletion of this antioxidant and to an increase in its oxidation rate. When duckweed was contaminated by folpet and the metal, an increase of the ascorbate pool size occurred from concentrations as low as 1 mg l^-1 and 50 μg l^-1 respectively. While the ascorbate pool became more oxidized because of exposure to copper concentrations ≤ 200 μg l^-1, folpet caused an increase in its reduction rate. Diuron was responsible for depletion of ascorbate, the redox status of which remained unchanged. Because it is an adaptation to stress and a defence process, the increase in the antioxidant pool size was proposed as a biomarker of exposure to an unsafe environment. Since depletion of antioxidant and an increase in its oxidation rate weakened cellular defences and indicated a precarious state, they could constitute early indicators of toxicity. So they were proposed as potential biomarkers of toxicity. It was concluded that the antioxidant content in duckweed might serve as a useful biomarker for monitoring water quality.     

Toxic effects of chlorpyrifos on the growth,hematology, and different organs histopathology of Nile tilapia,Oreochromis niloticus

Chlorpyrifos is a widely applied insecticide that permeates on most waterways and affects aquatic organisms. The growth performances, hematological and histological impacts on Nile tilapia, Oreochromis niloticus following a 60 day of exposure to varying concentrations of chlorpyrifos 20 EC (T₁ 08 µgL^?1, T₂ 16 µgL^?1, and T₃ 32 µgL^?1) were compared to a control T_c 0 µgL^?1. The 96-hour LC50 of chlorpyrifos 20 EC was calculated as 46.80 μgL^?1. The water quality parameters were recorded regularly. The value of dissolved O₂ and NH₃ stayed rather steady, although temperature varied considerably. It was revealed that as chlorpyrifos levels go up, the percentage of weight gain (WG %), specific growth rates (SGR), and survival rate decreases. The control group T_c had the highest percentages of SGR weight (1.16 ± 0.58) and the T₃ group had the lowest percentages of SGR weight (0.25 ± 0.77). The hematological assessment showed significant differences of hemoglobin concentration, white blood cell counts and red blood cell numbers between chlorpyrifos treatment and control group (P < 0.05). Histological alterations in the liver, gills, and muscle tissues reported to be worse for T₃ as compared to others. There were no statistical differences in GSI, HSI values between control and treatment groups. The chlorpyrifos 20 EC was shown to be highly toxic to O. niloticus at sub-lethal dosages.     

Identification of a biomarker for propetamphos and development of a biological monitoring assay

This paper describes the identification of a human metabolite of propetamphos ((E-O-2-isopropylcarbonyl-1-methylvinyl-O-methylethylphosphoramidothioate), formed by the hydrolytic cleavage of the enol-vinyl-phosphate bond, and the development of an analytical method suitable for biological monitoring of propetamphos exposure. The metabolite has been detected in the urine of exposed workers but not in that of control subjects. The analytical method involves azeotropic distillation of the urine with acetonitrile, followed by derivatization with pentafluorobenzyl bromide and analysis using gas chromatography with flame photometric detection.     

Degradation of contrasting pesticides by white rot fungi and its relationship with ligninolytic potential

The capacity of nine species of white rot fungus from a variety of basidiomycete orders to degrade contrasting mono-aromatic pesticides was investigated. There was no relationship between degradation of the dye Poly R-478, a presumptive test for ligninolytic potential, and degradation of the highly available pesticides diuron, metalaxyl, atrazine or terbuthylazine in liquid culture. However, there were significant positive correlations between the rates of degradation of the different pesticides. Greatest degradation of all the pesticides was achieved by Coriolus versicolor, Hypholoma fasciculare and Stereum hirsutum. After 42 days, maximum degradation of diuron, atrazine and terbuthylazine was above 86%, but for metalaxyl less than 44%. When grown in the organic matrix of an on-farm "biobed" pesticide remediation system, relative degradation rates of the highly available pesticides by C. versicolor, H. fasciculare and S. hirsutum showed some differences to those in liquid culture. While H. fasciculare and C. versicolor were able to degrade about a third of the poorly available compound chlorpyrifos in biobed matrix after 42 days, S. hirsutum, which was the most effective degrader of the available pesticides, showed little capacity to degrade the compound.     

典型环境污染物修复基因工程菌的构建及应用

随着人类活动的增加,对有机物和重金属的应用越来越广泛,同时造成的环境污染程度越来越严重.综述了石油、农药、表面活性剂及重金属类污染物治理中基因工程菌的构建及应用的研究进展,指出利用基因工程菌解决环境中的石油、农药、表面活性剂及重金属的污染问题已成为环境污染修复领域的研究热点,并提出基因工程菌的构建及应用过程中的难点及发展趋势.     

Population-related molecular responses on the effect of pesticides in Carassius auratus gibelio

The aim of this study was to evaluate population-related peculiarities of the adaptive responses of Carassius auratus gibelio. In order to do this, male specimens from polluted (B) and clean (Z) sites were exposed to commercial pesticides thiocarbamate Tatoo (9.1 μg·L(-1)and 91 μg·L(-1)) or tetrazine Apollo (2 μg·L(-1) and 10 μg·L(-1)) during fourteen days. The control fish from site B was distinguished by weakness of antioxidant defence (measured from superoxide dismutase and catalase activities, redox index of glutathione (GSH), superoxide anion (O(2)) and lipid peroxidation levels), imbalance of the concentrations of protein metallothionein (MT-SH) and MT-related metals (MT-Me) and neurotoxicity. Differences in glutathione-S-transferase activity in the liver and vitellogenin-like proteins in the serum were also showed between B and Z control groups. Common effects of pesticides were related to a decrease in GSH, an increase in O(2) production, ethoxyresorufin O-deethylase activity and hepatosomatic index. Apollo provoked particular elevation of MT-SH/MT-Me ratio. Population-related difference in the response was the activation of antioxidant defence in fish from site B and its inhibition in fish from site Z. The genotoxic effect of exposures was more expressed in fish from site B. Principal component analysis combine all exposed groups from site Z and control group from site B in one set, and separated each exposed group from site B. The main distinguishing index of each population selected by classification and regression tree analysis was MT-SH.     

Is the predatory mite <Emphasis Type="Italic">Kampimodromus aberrans</Emphasis> a candidate for the control of phytophagous mites in European apple orchards?

The most important biocontrol agents of phytophagous mites (mainly Tetranychidae) in European apple orchards are the predatory mites Amblyseius andersoni, Typhlodromus pyri and Euseius finlandicus (Phytoseiidae). A similar situation is found in Trentino (north-eastern Italy), an important apple production area in Europe. Another phytoseiid mite, Kampimodromus aberrans, can be dominant in neglected fruit orchards but is rare in commercial orchards because of its susceptibility to pesticides. However, pesticide resistant strains of K. aberrans have recently been found in vineyards. In the late 1990s, one of these resistant strains was successfully released on an experimental farm in Trentino. Kampimodromus aberrans spread to an apple orchard, despite the fact that it was colonized by T. pyri, A. andersoni and E. finlandicus, and became the dominant species. Since K. aberrans’ colonization appeared to be affected by apple cultivars, experiments were conducted on potted plants of three selected apple cultivars (Golden Delicious, Red Chief, Reinette du Canada). The results stressed the effect of cultivars on apple colonization by K. aberrans and suggested the role of leaf morphology in influencing this phenomenon. Field releases of K. aberrans were successfully performed in four commercial apple orchards. The incidence of K. aberrans in the total phytoseiid population increased over time and the predator became dominant in the season following its release in two orchards. Kampimodromus aberrans persists in these orchards as the dominant species. The adaptation of K. aberrans to varying environmental conditions, its tolerance to pesticides, and its competitiveness towards other phytoseiid species suggest a potential role of this species in the biological control of phytophagous mites in European apple orchards. Handling editor: Eric Lucas.     

Comparative analysis of organophosphate degrading enzymes from diverse species

Different types of organophosphorous compounds constitute most potent pesticides. These chemicals attack the nervous system of living organisms causing death. Different organisms produce enzymes to degrade these chemicals. These enzymes are present in simple microorganisms from archaea, bacteria to complex eukaryotes like humans. A comparison of representative eight shortlisted enzymes involved in the degradation and inactivation of organophosphates from a wide range of organisms was performed to infer the basis of their common functionality. There is little sequence homology in these enzymes which results in divergent tertiary structures. The only feature that these enzymes seem to share is their amino acid composition. However, structural analysis has shown no significant similarities among this functionally similar group of organophosphate degrading enzymes.     

截形叶螨药剂防治对比试验

截形叶螨(Tetranychus truncatus Ehara)在云南昆明主要为害大棚花卉,尤其对月季(Rosa chinensis)为害严重。使用玻片浸液法,选用6种化学杀螨剂和1种植物叶面保护剂对该叶螨进行室内药效测定;同时,选取真除螨、主力和植物叶面保护剂等3种杀螨剂实施田间防治试验。结果表明,室内施药48h后,真除螨2 000、3 000倍液杀螨效果达100%;田间喷药3d后,真除螨4 000倍液能达到30%的防治效果,可有效降低害螨数量。建议每年截形叶螨为害严重的5～11月期间,在保护地栽培的月季上连续施用真除螨。害螨发生高峰期前,可使用植物叶面保护剂,减少害螨的取食。