Genotoxic Effects of Aluminum on the Neotropical Fish Prochilodus lineatus

Applying an integrated approach using the Comet, micronucleus (MN), and random amplified polymorphic DNA (RAPD) assays, occurrence of erythrocytic nuclear abnormalities (ENAs) and the liver activity of antioxidants enzymes (catalase and glutathione-S-transferase (GST)) was carried out to evaluate the effects of acute (6, 24, and 96 h) and subchronic (15 days) exposures to aluminum on fish Prochilodus lineatus. The Comet assay showed that fish erythrocytes exhibited significantly higher DNA damage after 6 and 96 h of Al exposure. MN frequencies were very low and did not increase significantly after Al exposures, while ENAs frequency increased significantly after all exposure periods. RAPD profiles obtained with DNA from fish fins collected before the toxicity tests were compared to the profiles with DNA from gills and liver of the same fish sampled after Al exposures. Alterations in RAPD profiles, including appearance and disappearance of bands, after 6 h, 24 h, and 15 days of Al exposure were detected. Fish exposed to Al for 6 and 24 h also showed significant increases in GST and catalase activities. These results indicated that Al exposure was genotoxic to P. lineatus, inducing DNA damage in peripheral erythrocytes. The induction of antioxidant enzymes might be an indication that Al causes oxidative damage to DNA, while the very low frequency of MN suggests that Al does not produce clastogenic or aneugenic effects. Genotoxic effects after 15 days of Al exposure was revealed only by RAPD, showing that this assay represents a sensitive method to detect genotoxic damage, occasionally not detected by other genotoxic tests used in toxicological genetics studies.     

Direct in vivo evidence of protective effects of grape seed procyanidin fractions and other antioxidants against ethanol-induced oxidative DNA damage in mouse brain cells

Ethanol is a principle ingredient of alcoholic beverages with potential neurotoxicity and carcinogenicity, and the ethanol-associated oxidative DNA damage in the central nervous system is well documented. The present work studied the possible protective effects of grape seed oligomer and polymer procyanidin fractions against ethanol-induced toxicity and compared these with resveratrol and other well-known antioxidants (ascorbic acid and vitamin E). By using the single cell gel electrophoresis (comet assay), a simple and sensitive technique for genotoxicity studies, the potential genotoxicity of acute and chronic ethanol administration in the different brain regions was investigated. Acute ethanol administration, at the dose of 2.5 or 5.0 g kg(-1) i.p., could induce significant DNA damage in cerebellum and hippocampus. Chronic administration of ethanol at the dose of 2.5 or 5.0 g kg-1 p.o. for 30 days could induce significant DNA damage in cerebellum, hippocampus, hypothalamus, and cortex, which could be auto-repaired at least 3 days after ethanol withdrawal. Oral administration of grape seed oligomer and polymer procyanidins and resveratrol (25, 50, and 100 mg kg(-1)) for 3 days before acute ethanol (5.0 g kg(-1), i.p.) or repeated administration of these substances together with ethanol (5.0 g kg(-1), p.o.) for 30 consecutive days could significantly inhibit DNA damage in brain cells induced by ethanol. As compared, ascorbic acid (50, 100, and 200 mg kg(-1)) and vitamin E (100, 200, and 400 mg kg(-1)) could also present protective effects on ethanol-induced DNA damage. Furthermore, the concentrations of ethanol and acetaldehyde in brain regions of the mice were detected by gas chromatography after administration of ethanol plus antioxidants. All of the results indicated that ethanol could induce region-specific oxidative DNA damage in which the cerebellum and hippocampus were more vulnerable, but intake of grape seed procyanidins or other natural antioxidants could protect the brain against ethanol-induced genotoxicity.     

马拉硫磷对双齿围沙蚕乙酰胆碱酯酶和过氧化氢酶的影响

采用浓度梯度污染暴露室内模拟方法,研究了沙蚕暴露于不同浓度有机磷农药马拉硫磷的急性毒性效应,以及低浓度马拉硫磷对双齿围沙蚕乙酰胆碱酯酶（AChE）和过氧化氢酶（CAT）的影响。结果表明,马拉硫磷对沙蚕48、72、96h的LC50分别为71.68、49.21、33.16mg·L^-1,安全浓度为3.32mg·L^-1。在低浓度（0.0018～9mg·L^-1）马拉硫磷中暴露3和6d,沙蚕体内乙酰胆碱酯酶活性受到显著抑制,暴露6d时9mg·L^-1浓度组最高抑制率达88.92%,且乙酰胆碱酯酶抑制率与马拉硫磷浓度对数具有显著的剂量效应。沙蚕CAT活性随马拉硫磷浓度增加表现出先降后升再降的趋势,暴露3d时0.018mg·L^-1浓度组CAT活性最高,6d时0.18mg·L^-1浓度组CAT活性最高,分别比对照组高52.02%和53.42%（P〈0.05）,而浓度达1.8mg·L^-1时CAT活力均显著下降（P〈0.05）。结果显示,沙蚕乙酰胆碱酯酶是较好的滩涂有机磷农药污染生物标记物。     

Two-year toxicity and carcinogenicity study of methyleugenol in F344/N rats and B6C3F(1) mice

Methyleugenol (MEG) was tested for toxicity/carcinogenicity in a 2-yr carcinogenesis bioassay because of its widespread use in a variety of foods, beverages, and cosmetics as well as its structural resemblance to the known carcinogen safrole. F344/N rats and B6C3F(1) mice (50 animals/sex/dose group) were given MEG suspended in 0.5% methylcellulose by gavage at doses of 37, 75, or 150 mg/kg/day for 2 yr. Control groups (60 rats/sex and 50 mice/sex) received only the vehicle. A stop-exposure group of 60 rats/sex received 300 mg/kg/day by gavage for 53 weeks followed by the vehicle only for the remaining 52 weeks of the study. A special study group (10 animals/sex/species/dose group) were used for toxicokinetic studies. All male rats given 150 and 300 mg/kg/day died before the end of the study; survival of female rats given 150 mg/kg/day and all treated female mice was decreased. Mean body weights of treated male and female rats and mice were decreased when compared to control. Area under the curve results indicated that greater than dose proportional increases in plasma MEG occurred for male 150 and 300 mg/kg/day group rats (6 and 12 month) and male 150 mg/kg/day mice (12 month). Target organs included the liver, glandular stomach, forestomach (female rats) and kidney, mammary gland, and subcutaneous tissue (male rats). Liver neoplasms occurred in all dose groups of rats and mice and included hepatoadenoma, hepatocarcinoma, hepatocholangioma (rats only), hepatocholangiocarcinoma, and hepatoblastoma (mice only). Nonneoplastic liver lesions included eosinophilic and mixed cell foci (rats only), hypertrophy, oval cell hyperplasia, cystic degeneration (rats only), and bile duct hyperplasia. Mice also exhibited necrosis, hematopoietic cell proliferation, and hemosiderin pigmentation. Glandular stomach lesions in rats and mice included benign and malignant neuroendocrine tumors, neuroendocrine cell hyperplasia, and atrophy and in mice included glandular ectasia/chronic active inflammation. In female rats, the forestomach showed a positive trend in the incidences of squamous cell papilloma or carcinoma (combined). Male rats also exhibited kidney (renal tubule hyperplasia, nephropathy, and adenomacarcinoma), mammary gland (fibroadenoma), and subcutaneous tissue (fibroma, fibrosarcoma) lesions. Male rats also exhibited malignant mesotheliomas and splenic fibrosis. These data demonstrate that MEG is a multisite, multispecies carcinogen.     

Preformed Biomarkers Including Dialkylphosphates (DAPs) in Produce May Confound Biomonitoring in Pesticide Exposure and Risk Assessment

Low levels of pesticides and their metabolites/degradates occur in produce when pesticides are used in conventional or organic crop protection. Human dietary and nonoccupational urine biomonitoring studies may be confounded by preformed pesticide biomarkers in the diet. The extent of formation of putative urine biomarkers, including malathion specific (MMA, MDA; malathion mono- and diacids), organophosphorus generic (DMP, DMTP, DMDTP; dimethyl-, dimethylthio-, and dimethydithiophosphate), pyrethroid generic (3-PBA; 3-phenoxybenzoic acid), and captan-specific metabolites (THPI; tetrahydrophthalimide), was measured in produce samples containing the parent pesticide. Every produce sample of 19 types of fruits and vegetables contained biomarkers of potential human exposure. A total of 134 of 157 (85%) samples contained more molar equivalent biomarkers than parent pesticide. Malathion and fenpropathrin were sprayed (1 lb/A), and the time-dependent formation of pesticide biomarkers in strawberries was investigated under field conditions typical of commercial production in California. Malathion and fenpropathrin residues were always below established residue tolerances. Malathion, MMA, and MDA dissipated, while DMP, DMTP, and DMDTP increased, during a 20 day study period following the preharvest interval. The mole ratios of biomarkers/(malathion + malaoxon) were always greater than 1 and increased from day 4 to day 23 postapplication. Fenpropathrin and 3-PBA also dissipated in strawberries during each monitoring period. The mole ratios of 3-PBA/fenpropathrin were always less than 1 and decreased from day 4 to day 14. The absorption of pesticide biomarkers in produce and excretion in urine would falsely indicate consumer pesticide exposure if used to reconstruct dose for risk characterization.     

Ibuprofen Genotoxicity in Aquatic Environment: An Experimental Model Using Oreochromis niloticus

Medicines and their metabolites have been found as water contaminants at very low concentrations; moreover, there is no extensive toxicological data to determine the risks associated with their occurrence in water resources. The ibuprofen genotoxicity potential to the Oreochromis niloticus fish (Tilapia), due to nanograms per liter exposure, was evaluated using the micronucleus test. Acute (48 h) and sub-chronic assays (10 days) were carried out at 300 ng/L ibuprofen aquatic concentration comparing with the negative control group (without treatment), with eight animals per group. The results were assessed from the average of triplicate analyses. The micronucleus frequency in peripheral blood of fish was determined using a sample size of 3,000 erythrocytes per animal. Significance was defined using t test (p????0.05). The bioassay results showed a statistically significant increase in the frequency of micronuclei for both exposure times in comparison to the negative control. The micronucleus frequency observed for the sub-chronic tests was higher than the one identified in the acute assays. The observed ibuprofen genotoxic effects demonstrated an aquatic environmental risk of this pharmaceutical, which occurs for the used fish experimental model in lower concentration than previously described for other aquatic organisms.     

Degradation of malathion, in aqueous extracts of asparagus (Asparagus officinalis)

Malathion was incubated in water extracts of vegetables at various temperatures and pH, and the amount of malathion present over time was analyzed by a gas chromatograph with a flame photometric detector. Malathion was degraded to a nondetectable level in a 1% asparagus extract incubated at pH 7.4 and 37 degrees C for 4 h. Carrot extract showed the second highest rate of malathion degradation (76%), followed by kale extract (23.7%), spinach extract (9.7%), and broccoli extract (1.5%) under the same conditions. The highest degradation rates of malathion were observed at 37 degrees C, when three different temperatures were tested (5, 25, and 37 degrees C) at pH 7.4. Rate constants were 0.134 min(-)(1) from a 1% asparagus solution and 0.095 min(-)(1) from a 0.5% asparagus solution. The highest degradation rate of malathion was achieved at pH 9 among the pHs tested (pH 4, 7.4, and 9) in a 0.5% asparagus solution. The 0.5% asparagus solution degraded dicarboxylic acid esters by almost 100% for dimethyl succinate and diethyl adipate, by 64% for diethyl acetyl succinate, and 30% for diethyl benzyl malonate when incubated at pH 9 for 20 min. The results support the hypothesis that the enzyme that degrades malathion in the asparagus solutions is a carboxylesterase.     

Neuroprotective effects of resveratrol on cerebral ischemia-induced neuron loss mediated by free radical scavenging and cerebral blood flow elevation

Resveratrol is a natural phytoestrogen and possesses many biological functions such as anti-inflammatory activity and protection against atherosclerosis and myocardial infraction. The present study was carried out to elucidate the neuroprotective effect and possible mechanism of resveratrol on cerebral ischemia-induced hippocampus neuron loss. Sixty adult male rats underwent general anesthesia (urethane, 1.4 g/kg, i.p.) and were divided into three groups: sham operation, ischemia treatment, and ischemia combined with resveratrol administration (20 mg/kg, i.v.). The carotid artery was bilaterally ligated to induce cerebral ischemia. Microdialysis and high-performance liquid chromatography were used to analyze dihydroxybenzoic acid (DHBA) that reflected the hippocampal hydroxyl radical level. Hippocampal nitric oxide was assayed among different groups. During cerebral ischemia, the hydroxyl radical levels were elevated in rats and animals displayed severe neuronal loss. A single dose of resveratrol significantly increased the nitric oxide level and decreased the hydroxyl radical level. The reduction of cerebral blood flow and neuronal loss were also attenuated by resveratrol treatment. The results demonstrated that a single infusion of resveratrol could elicit neuroprotective effects on cerebral ischemia-induced neuron damage through free radical scavenging and cerebral blood elevation due to NO release.     

Protective effect of Mesona procumbens against tert-butyl hydroperoxide-induced acute hepatic damage in rats

The protective effect of Hsian-tsao (Mesona procumbens Hemsl.) and its active compounds on liver damage was evaluated using the model of tert-butyl hydroperoxide (t-BHP)-induced acute hepatic damage in rats. Male Sprague-Dawley rats (200 +/- 10 g) were orally pretreated with a water extract of Hsian-tsao (WEHT) (0.1, 0.5, and 1.0 g/kg) or caffeic acid (0.1 g/kg of body weight) for 13 days before a single dose of t-BHP (0.2 mmol/kg, intraperitoneally) to each animal, and the rats were sacrificed 18 h later by decapitation; blood samples were collected for the assays of serum biochemical values. The livers were excised from the animals and assayed for oxidative injury, antioxidant enzyme, and pathological histology. The result showed that the oral pretreatment of WEHT (0.1, 0.5, and 1.0 g/kg) or caffeic acid (0.10 g/kg) before t-BHP (0.2 mmol/kg) treatment significantly lowered the serum levels of the hepatic enzyme markers (alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase) and reduced oxidative stress of the liver by evaluation of malondialdehyde, glutathione, 8-hydroxy-2'-deoxyguanosine, glutathione peroxidase, and glutathione reductase. The histopathological evaluation of the rat livers showed that WEHT and caffeic acid reduced the incidence of liver lesions including cloudy swelling, pyknosis, and cytolysis induced by t-BHP in rats. On the basis of the results of this study, it can be speculated that M. procumbens protects liver against t-BHP-induced hepatic damage in rats.     

Degradation of malathion and phenthoate by glutathione reductase in wheat germ

Residual malathion in wheat was estimated at a lower value when analysis was performed by extraction with acetone after addition of water to swell the wheat, according to the Japanese Bulletin Method. The supernatant of the wheat homogenate showed degradation not only of malathion but also of phenthoate. Malathion and phenthoate were not degraded by the boiled supernatant of the wheat homogenate. It was presumed for this reason that glutathione reductase (GR; EC 1.6. 4.2) in the wheat degraded malathion. The following results were obtained: (1) GR originating in wheat could degrade malathion and phenthoate. (2) The degradation of malathion by the GR was inhibited by excessive GSSG. (3) There was a high correlation between GR activity and malathion degradation activity of the supernatant of wheat homogenates. It is likely that GR acted on the specific structure of malathion and phenthoate, the S=P-S bond, and the blanch structure bonding with the sulfur atom. Following the above, extraction with acetone after addition of water (the Japanese Bulletin Method) should be replaced by extraction with pure organic solvent and without addition of water for swelling.     

Protective effect of supplementation of fish oil with high n-3 polyunsaturated fatty acids against oxidative stress-induced DNA damage of rat liver in vivo

The present study was undertaken to know the effect of supplementation of fish oil with high n-3 polyunsaturated fatty acids (PUFA) on oxidative stress-induced DNA damage of rat liver in vivo. Male Wistar rats were fed a diet containing fish oil or safflower oil with high n-6 PUFA at 50 g/kg of diet and an equal amount of vitamin E at 59 mg/kg of diet for 6 weeks. Livers of rats fed fish oil were rich in n-3 PUFA, whereas those of rats fed safflower oil were rich in n-6 PUFA. Ferric nitrilotriacetate was intraperitoneally injected to induce oxidative stress. The degree of lipid peroxidation of the liver was assessed by the levels of phospholipid hydroperoxides and thiobarbituric acid-reactive substances (TBARS), and the degree of oxidative DNA damage was assessed by comet type characterization in alkaline single-cell gel electrophoresis and 8-hydroxy-2'-deoxyguanosine levels. The levels of TBARS of the livers of the fish oil diet group increased to a greater extent than those of the safflower oil diet group, whereas the levels of the hydroperoxides of the livers of both diet groups increased to a similar extent. The vitamin E level of livers of the fish oil diet group was remarkably decreased. The degree of DNA damage of both diet groups was increased, but the increased level of the fish oil diet group was remarkably lower than that of the safflower oil diet group. The above results indicate that fish oil supplementation does not enhance but appears to protect against oxidative stress-induced DNA damage and suggest that lipid peroxidation does not enhance but lowers the DNA damage.     

应用微核试验和单细胞凝胶电泳技术检测农药对蜘蛛的遗传毒性

应用蜘蛛血细胞微核试验和单细胞凝胶电泳试验研究了两种杀虫剂——吡虫啉和阿维菌素对蜘蛛头胸部和腹部的遗传毒性。结果表明:各供试浓度吡虫啉和阿维菌素对蜘蛛血细胞微核率均有明显影响,与对照组相比有显著性差异(P<0.05,P<0.01);且随着两种农药浓度升高,血细胞微核率显著增加,存在明显的剂量效应关系(吡虫啉浓度与星豹蛛头胸部血细胞微核率相关系数r=0.672 8,腹部为r=0.800 6;阿维菌素与星豹蛛头胸部血细胞微核率相关系数r=0.989 9,腹部为r=0.985 8)。吡虫啉和阿维菌素对星豹蛛血细胞DNA损伤有明显的剂量效应关系(吡虫啉浓度与星豹蛛头胸部血细胞DNA损伤相关系数r=0.948 2,腹部为r=0.970 4;阿维菌素与星豹蛛头胸部血细胞DNA损伤相关系数r=0.978 1,腹部为r=0.975 6)。两种农药在同一浓度下,对星豹蛛腹部血细胞微核率和DNA损伤程度明显大于头胸部。     

Genotoxicity of glycidamide in comparison to 3-N-nitroso-oxazolidin-2-one

Acrylamide (AA) is generated by thermal processing of foods, depending on processing conditions and precursor availability. AA is not genotoxic by itself but becomes activated to its genotoxic metabolite glycidamide (GA) via epoxidation, mediated primarily by cytochrome P450 2E1. In the Comet assay in V79 cells and in human lymphocytes, GA induced DNA damage down to 300 microM concentration (4 h). After post-treatment with the DNA repair enzyme formamidopyrimidine-DNA-glycosylase (FPG), DNA damage became already detectable at 10 microM (4 h). By comparison, the N-nitroso compound 3- N-nitroso-oxazolidin-2-one (NOZ-2) is a much stronger genotoxic agent, significantly inducing DNA damage already at 15 min (3 microM). Post-treatment with FPG in this case did not enhance response. GA induced DNA damage in V79 cells rather slowly, with first response detectable at 4 h. The hPRT forward mutation test encompasses 5 days of expression time during which also repair can take place. GA-induced hPRT mutations only became detectable at concentrations of 800 microM and above. This is 80-fold higher than the lowest significant response to GA in the Comet assay (10 microM with FPG). In contrast, NOZ-2 was as effective in the hPRT test as in the Comet assay (3 microM). These results demonstrate substantial differences in the genotoxic potency of GA and NOZ-2. Whereas NOZ-2 is a pontent genotoxic mutagen, GA in comparison shows only low genotoxic and mutagenic potential, presumably as a result, at least in part, of preferential N7-G alkylation.     

Inhibition of reactive nitrogen species effects in vitro and in vivo by isoflavones and soy-based food extracts

Recent studies have shown that soy isoflavone inhibits inducible nitric oxide (NO) synthase activities and is reported to have peroxynitrite scavenging ability. Consequently, we investigated whether isoflavones (daidzein and genistein) and extracts from soy-based products (miso, soymilk, tofu, soy sprout, black soybean, soybean, and yuba) would inhibit the reactive nitrogen species (RNS) effect in vitro and in vivo. In the in vitro experiments [including the protection of cellular DNA from peroxynitrite or sodium nitroprusside damage, an inhibitory effect on nitric oxide production from lipopolysaccharide (LPS)-induced RAW 264.7 cells, and nitric oxide scavenging ability], extracts from soy-based foods showed a potent antioxidant activity and an inhibiting effect on RNS activity. These effects were correlated with total isoflavone content. In the in vivo experiments, rats were given isoflavones (4.0 mg/kg bw) or soy-based product extracts (1.0 g/kg bw) orally for 1 week and were injected with vehicle H(2)O (1 mL/kg bw) or LPS (10 mg/kg bw) on the day 7. Twelve hours after treatment, the rats were killed, and blood serum was collected for analysis. The intraperitoneal administration of LPS resulted in an increase in serum nitrite, nitrate, and nitrotyrosine concentrations. These are stable metabolite end products of nitric oxide, to 4-, 16-, and 5-fold levels, (4, 10 microM and 58 +/- 14 pmol/mL), of the placebo control, respectively. Results showed that oral administration of isoflavones and extracts from soy-based products significantly decreased serum nitrite, nitrate, and nitrotyrosine levels in LPS-induced rats. This study demonstrates that soy isoflavone supplementation may inhibit RNS-induced oxidation both in vitro and in vivo.     

Antioxidant activities of phenolic acids on ultraviolet radiation-induced erythrocyte and low density lipoprotein oxidation

The exposure of mammalian cells to UV light induces various deleterious responses. Some of the major harmful effects are DNA damage, cell membrane peroxidation, systemic immune suppression, and aging acceleration. Reactive oxygen species and free radicals are believed to be largely responsible for some of the deleterious effects of UV upon cells. Typical administration of antioxidants has recently proved to represent a successful strategy for protecting the cells against UV-mediated oxidative damage. The objective of this study was to investigate the inhibitory effect of phenolic acids (caffeic acid, ferulic acid, gallic acid, and protocatechuic acid) on oxidative damage in human erythrocytes and low-density lipoprotein (LDL) induced by UVB radiation. The results revealed that the thiobarbituric acids reactive substances induced by UVB were decreased from 2.78 to 0.12-0.89 nmol MDA/mg protein in erythrocyte ghost and from 0.72 to 0.14-0.43 nmol MDA/mg protein in LDL by the addition of phenolic acids (100 muM). Caffeic acid, ferulic acid, and gallic acid exhibited over 85 and 60% inhibitory effect toward UVB-induced oxidation in erythrocytes and LDL, respectively. Phenolic acids, especially gallic acid, could maintain the normal glutathione levels and glutathione peroxidase activity in hemolysate from erythrocytes that were exposed to UVB radiation in comparison with untreated control. The results indicate that the antioxidant activities of caffeic acid and ferulic acid play a potential role in protection against UVB oxidative damage to human erythrocytes and LDL.     

Inhibitory effects of Cassia tora L. on benzo[a]pyrene-mediated DNA damage toward HepG2 cells

The effects of water extracts from Cassia tora L. (WECT) treated with different degrees of roasting on benzo[a]pyrene (B[a]P)-induced DNA damage in human hepatoma cell line HepG2 were investigated via the comet assay without exogenous activation mixtures, such as S9 mix. WECT alone, at concentrations of 0.1-2 mg/mL, showed neither cytotoxic nor genotoxic effect toward HepG2 cells. B[a]P-induced DNA damage in HepG2 cells could be reduced by WECT in a dose-dependent manner (P < 0.05). At a concentration of 1 mg/mL, the inhibitory effects of WECT on DNA damage were in the order unroasted (72%) > roasted at 150 degrees C (60%) > roasted at 250 degrees C (23%). Ethoxyresorufin-O-dealkylase activity of HepG2 cells was effectively inhibited by WECT, and a similar trend of inhibition was observed in the order unroasted (64%) > roasted at 150 degrees C (42%) > roasted at 250 degrees C (18%). The activity of NADPH cytochrome P-450 reductase was also decreased by unroasted and 150 degrees C-roasted samples (50% and 38%, respectively). Furthermore, glutathione S-transferase activity was increased by treatment with unroasted (1.26-fold) and 150 degrees C-roasted (1.35-fold) samples at 1 mg/mL. In addition, the contents of anthraquinones (AQs) in WECT, including chrysophanol, emodin, and rhein, were decreased with increasing roasting temperature. Each of these AQs also demonstrated significant antigenotoxic activity in the comet assay. The inhibitory effects of chrysophanol, emodin, and rhein on B[a]P-mediated DNA damage in HepG2 cells were 78, 86, and 71%, respectively, at 100 microM. These findings suggested that the decreased antigenotoxicity of the roasted samples might be due to a reduction in their AQs content.     

A Chronic Plant Test for the Assessment of Contaminated Soils. Part 1: Method development (9 pp)

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PREAMBLE According to the German Federal Soil Protection Act (BBodSchG 1998), the habitat function of soils must be protected. Despite the fact that in the Federal Soil Protection Ordinance (BBodSchV 1999) it has not been established how this goal can be reached reliably, it is clear that such a biological function can only adequately be assessed using biological test methods. This is especially true when a soil is contaminated by a mixture of often unknown chemicals. In such a case the use of chemical analysis aiming at a small range of known substances is not sufficient and must therefore be supplemented by biological methods. For this reason, several standardised test methods are available (e.g. using earthworms, collembolans or plants; Römbke and Knacker 2003; ISO 2003). Since acute tests are usually not sensitive enough for the assessment of potentially contaminated soils (e.g. Hund-Rinke et al. 2002), chronic tests like the earthworm reproduction tests (ISO 1998) are recommended for this purpose.

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A chronic plant test for the determination of phytotoxicity was missing until quite recently. The term phytotoxicity is understood here as the capacity of a compound or a contaminated soil to cause temporary or long-lasting damage to plants (EPPO 1997). Therefore, the German Ministry for Education and Research sponsored a project (1997 – 1999) in which – based on existing standardised methods – such a chronic plant laboratory test was developed and partly validated (Kalsch and Römbke 2000). The new test can be used for the evaluation of single chemicals (see Part 1 of this mini-series) as well as for the assessment of contaminated or remediated soils (see Part 2 of this mini-series).

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ABSTRACT Background and Scope. As part of the efforts to improve the biological testing of contaminated soils, the German government sponsored the standardisation of a chronic plant bioassay. This new test is based on experiences with various acute plant tests (e.g. published by OECD or ISO) and existing North American Plant-Life-Cycle Bioassays. In this contribution the characteristic properties of the test are described.

Methods

The test can be performed either with Brassica rapa (turnip) or Avena sativa (oat). Its duration is 35 to 64 days with OECD artificial soil and a German standard field soil acting as controls. Water and nutrients are provided by an automatic wick irrigation system. Besides measuring biomass and shoot length, the number of pods, seeds and flowers are applied as chronic measurement endpoints. During the development of the test, TNT (2,4,6-trinitrotoluene) and Pyrene were used as model test substances.

Results

Pyrene did not affect B. rapa (turnip) in concentrations of up to 10.000 mg/kg soil (due to the often low sensitivity of A. sativa (oat) no further test with this substance was performed). Depending on the endpoint the results varied in the tests with TNT. With few exceptions, the NOEC (No Observed Effect Concentration) values were determined as 55.5 mg TNT/kg soil for B. rapa (turnip) and as 75 (unfertilised) and 150 (fertilised) mg TNT/kg soil for A. sativa (oat). The EC50-values varied between 96.3 and 207.2 mg TNT/kg soil for B. rapa (turnip) and 183.1 – 505.6 mg TNT/kg soil for A. sativa (oat), depending on the endpoint.

Outlook

The results of this work have been used to prepare a draft test guideline, which has recently been standardised by the International Organisation for Standardisation (ISO). Practical experiences with this test system are described in Part II of this mini series.     

Acute and chronic toxicity of malathion to the freshwater cladoceran Moina macrocopa

The acute and chronic effects of the organophosphate insecticide malathion on the cladoceran Moina macrocopa were studied. The 24, 48 and 72 h LC50 values for malathion were between 5.00 and 10.00 μg L^?1. Survival, longevity and the number of young produced by the population were affected by exposure to 0.01 μg L^?1 or higher concentrations. Exposure to malathion had no effect on the age of first reproduction.     

Hematological and pathological effects of chromium toxicosis in the freshwater fish,Barbus conchonius Ham

Experimental exposure to Cr(VI) induced anomalies in the peripheral blood and tissues of a freshwater fish, Barbus conchonius. Clinical findings in the blood corpuscles included swelling of erythrocytes, numerous circulating polychromatophils, and vacuolation of large lymphocytes during acute exposure. Poikilocytosis, severe cytoplasmic vacuolation and deterioration of cytoplasmic membrane in erythrocytes occurred following chronic exposure. Significant polycythemia with collateral rise in Hb and Hct were manifest in the acutely intoxicated fish. By contrast, chronic exposure caused marked erythropenia and an accompanying reduction in Hb and Hct values. Leucocyte subpopulations showed an initial rise and then a fall in the thrombocytes together with a significant lymphocytosis, neutropenia, and basophilia. Pathological changes were observed in the gills, kidneys, and liver of Cr-exposed fish.     

手掌参多糖对60Co-γ射线辐射小鼠造血和抗氧化功能损伤的治疗作用研究

为研究手掌参多糖对电离辐射损伤小鼠造血和抗氧化功能的治疗作用,本试验选用48只健康雌性昆明小白鼠,随机分为8组,分别为空白组,辐射组,手掌参多糖低、中、高给药组(150、300、600 mg·kg^-1 组)和辐射低、中、高给药组;辐射组和辐射给药组分别用⁶⁰Co-γ射线进行辐射,辐射剂量5.0 Gy(剂量率0.8 Gy·min^-1)。分别在照射后 30 min内灌胃相应剂量的手掌参多糖和生理盐水(空白组、辐射组),连续5 d。末次灌胃后48 h内测定所有小鼠外周血细胞计数、脾脏指数、肝脏超氧化物歧化酶(SOD)活性、总抗氧化能力(T-AOC)、丙二醛(MDA)含量、骨髓DNA含量、骨髓嗜多染红细胞微核 (MN) 数目及脾脏T淋巴细胞亚群。结果表明,与空白组相比,给药组小鼠抗氧化能力和造血系统得到不同程度的改善,辐射组外周血细胞计数、脾脏指数、骨髓DNA含量、肝脏抗氧化能力及T淋巴细胞亚群极显著降低,MDA含量与MN数目显著升高; 与辐射组相比,辐射给药组小鼠脾脏指数和T-AOC、SOD活性极显著升高,DNA含量、外周血细胞计数也有所升高,CD3⁺、CD4⁺、CD8⁺ T淋巴细胞比率升高,MDA含量、MN数目显著降低。上述试验结果表明,手掌参多糖对⁶⁰Co-γ射线照射造成的小鼠造血、抗氧化功能损伤具有治疗作用。本研究为手掌参多糖对辐射损伤的治疗提供了技术参考。