Impact of Elevated CO<Subscript>2</Subscript> and O<Subscript>3</Subscript> Concentrations on Biogenic Volatile Organic Compounds Emissions from <Emphasis Type="Italic">Ginkgo biloba</Emphasis>

In natural environment with ambient air, ginkgo trees emitted volatile organic compounds 0.18 μg g⁻¹ h⁻¹ in July, and 0.92 μg g⁻¹ h⁻¹ in September. Isoprene and limonene were the most abundant detected compounds. In September, α-pinene accounted for 22.5% of the total. Elevated CO₂ concentration in OTCs increased isoprene emission significantly in July (p < 0.05) and September (p < 0.05), while the total monoterpenes emission was enhanced in July and decreased in September by elevated CO₂. Exposed to elevated O₃ increased the isoprene and monoterpenes emissions in July and September, and the total volatile organic compounds emission rates were 0.48 μg g⁻¹ h⁻¹ (in July) and 2.24 μg g⁻¹ h⁻¹ (in September), respectively. The combination of elevated CO₂ and O₃ did not have any effect on biogenic volatile organic compounds emissions, except increases of isoprene and Δ3-carene in September. Foundation item: The National Natural Science Foundation of China (No. 90411019).     

Use of <Emphasis Type="Italic">Solen brevis</Emphasis> as a Biomonitor for Cd,Pb and Zn on the Intertidal Zones of Bushehr–Persian Gulf,Iran

The concentrations of Zn, Cd and Pb were determined in tissues (shell and soft tissue) of 144 of bivalve mollusks (Solen brevis) and 15 samples of surface sediment collected from three locations in intertidal zones of Bushehr coast, Persian Gulf, Iran in May 2011. The mean concentrations of Zn, Cd and Pb in the sediment samples were 26.2, 1.25, and 21.1 μg/g dw, respectively. The mean levels of Zn, Cd and Pb in the clam samples were 63.3, 0.67, and 4.38 μg/g dw in soft tissue and 10. 7, 1.53, and 15.6 μg/g dw in shell, respectively. The degrees of variability (CV %) for Cd and Pb within the shells were lower than for soft tissues, whereas the CV for Zn was lower in the soft tissue than in the shell, indicating that there is more precision (lower CV) in the determination of Cd and Pb in the shells and Zn in the soft tissues. Significant correlation were found between Cd (r = 0.63; p < 0.05) and Pb (r = 0.78; p < 0.01) concentrations in the shell of S. brevis and their concentrations in the surface sediments. Indeed, Zn concentrations in the soft tissue of S. brevis significantly (r = 0.63; p < 0.05) correlated with Zn concentrations in surface sediments. The results of this study suggest that the shell of S. brevis may serve as a reliable biomonitor for Cd and Pb, and the soft tissue for Zn.     

Metabolic Conversion of 1,1-Dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) to 1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) in the Male F344/NCr Rat

1,1-Dichloro-2,2-bis(p-chlorophenyl)ethane (DDD) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) levels were measured by capillary gas chromatography with electron capture detection in liver and blood serum of male F344/NCr rats exposed for 2 weeks to DDD at dietary concentrations ranging from 8.51 ppm to 2,000 ppm. DDD burdens in serum ranged from <0.006 μM (limit of detection) in control rats to 1.1 μM in the rats fed DDD at 2,000 ppm. The corresponding liver burdens in these animals ranged from <0.006 μmol/kg liver (controls) to 11 μmol/kg liver in rats fed DDD at 2,000 ppm. Levels of DDE in serum or liver were undetectable (<0.006 μM in serum; <0.006 μmol/kg liver) in rats fed control diet or diet containing 8.51 or 25.5 ppm DDD. The liver and serum burdens of DDE increased with dietary DDD concentration, reaching a maximum of 0.53 μM in serum and 4.7 μmol/kg liver in rats fed 2,000 ppm DDD. As a percentage of total DDD equivalents detected in liver or serum, the DDE burdens increased to a maximum of 36% and 31% in the serum and liver, respectively, of rats fed 689 ppm DDD. The possibility that the DDE might have been generated artifactually in the diet prior to administration to the rats was ruled out by analysis with capillary gas chromatography of the diet containing 2,000 ppm DDD. The identification of DDE as a metabolite in liver extracts of rats fed 2,000 ppm DDD was confirmed with GC-MS. The results confirmed the presence of DDE as a metabolite of DDD. Received: 18 August 1997/Accepted: 6 January 1998     

Protective Role of Gallic Acid on Sodium Fluoride Induced Oxidative Stress in Rat Brain

Gallic acid is known as a potent antioxidant active compound of the edible and medicinal plant Peltiphyllum peltatum. The main objective of this study was to evaluate the neuroprotective effects of gallic acid against sodium fluoride induced oxidative stress in rat brain. Gallic acid (10 and 20 mg/kg) and vitamin C (10 mg/kg) were intraperitoneally administrated for 1 week prior to sodium fluoride intoxication. After the treatment period, brain tissues were collected and homogenized, and antioxidant parameters were measured in the homogenates. The level of thiobarbituric acid reactive substances in sodium fluoride intoxicated rats (42.04 ± 2.14 nmol MDA eq/g tissue, p < 0.01 vs. normal) increased compared to the normal rats (35.99 ± 1.08 nmol MDA eq/g tissue). Pretreatment with gallic acid at 20 mg/kg was exhibited significant reduction in the thiobarbituric acid reactive substances level (37.06 ± 1.4 nmol MDA eq/g tissue, p > 0.05 vs. normal). This increasing in thiobarbituric acid reactive substances level was accompanied with a decrease in the level of reduced glutathione (6.74 ± 0.28 μg/mg of protein, p < 0.001 vs. normal), superoxide dismutase (53.24 ± 1.62 U/mg of protein, p < 0.001 vs. normal) and catalase (70.73 ± 2.94 μmol/min/mg of protein p < 0.001 vs. normal) activities in sodium fluoride intoxicated rat. Gallic acid at 20 mg/kg was significantly modified the level of reduced glutathione (11.02 ± 0.53 μg/mg of protein, p < 0.05 vs normal) and catalase activity (89.22 ± 3.67 μmol/min/mg of protein, p > 0.05 vs. normal) in rat brain. However, gallic acid at 20 mg/kg was significantly more effective in retrieving superoxide dismutase (124.78 ± 5.7 U/mg of protein) activity than vitamin C (115.5 ± 4.97 U/mg of protein).     

Alleviation Effect of Alginate-Derived Oligosaccharides on Vicia faba Root Tip Cells Damaged by Cadmium

Cadmium has been shown to prevent Vicia faba growth by inhibiting cell mitosis. In this study we investigated the role of Alginate-derived Oligosaccharides (ADO) in alleviating Vicia faba root tip cells damaged by 6 and 8 mg L⁻¹ CdCl₂. Micronucleus assay and chromosomal aberration assay were used to determine mitotic index, micronucleus frequency and chromosomal aberration frequency. The results showed that micronucleus frequency of Vicia faba root tip cells was inhibited under all the ADO concentrations. Especially, the inhibition ratio of 0.125% ADO highly reached 66.11 and 67.17% in 6 and 8 mg L⁻¹ CdCl₂, respectively. Furthermore, the mitotic index increased (p < 0.05) and chromosomal aberration frequency decreased (p < 0.05) under all the ADO concentrations. This indicated that ADO had a significant alleviation effect on Vicia faba root tip cells damaged by cadmium.     

Coartemether induced oxidative and hepatic damage in Plasmodium berghei strain Anka infected mice

This study investigated the effect of coartemether on antioxidant and hepatotoxic biomarkers in Plasmodium berghei infected mice. Erythrocyte, hepatic and renal superoxide dismutase (2.71 ± 0.51; 1.96 ± 0.87; 2.84 ± 0.22 Units/mg protein respectively) and catalase (4.10 ± 0.10; 8.25 ± 1.24; 6.28 ± 0.11 Units/mg protein respectively) activities were significantly (p < 0.05) elevated in “parasitized and treated” (PnT) animals. Renal glutathione level (19.02 ± 0.20 μg/mL) was elevated in PnT animals. Glutathione S-transferase and malondialdehyde levels in hepatic (8.76 ± 0.49 μmol/min/mg; 527.23 ± 24.56 mmol/dL) and renal (3.35 ± 0.30 μmol/min/mg; 464.42 ± 59.13 mmol/dL) tissues were significantly high (p < 0.05) in coartemether-treated animals alone. Plasma aspartate transferase (9.45 ± 3.59 U/L) and alanine transferase (5.78 ± 2.36 U/L) were high in PnT animals. Therefore, data indicates that in the presence of P. berghei, coartemether could alter the antioxidant status and induce hepatotoxic damage in mice.     

Arsenic Concentrations in Soils Impacted by Dam Failure of Coal-Ash Pond in Zemianske Kostolany,Slovakia

In this study, the concentrations of arsenic were determined in the soils around old coal-ash pond. The soils in the study area were severely contaminated with arsenic after dam failure of the coal-ash pond. The mean concentrations of arsenic in soils collected from three sampling depths of 0–20, 20–40 and >40 cm were 173, 155 and 426 μg/g, respectively, exceeding greatly the Dutch intervention threshold for this element. Arsenic concentrations were positively correlated with total iron and aluminium contents in the soils (r = 0.73, p < 0.001 and r = 0.72, p < 0.001, respectively), indicating that oxyhydroxides of iron and aluminium may control the distribution of arsenic in these soils. Ammonium nitrate extractant was used to mimic availability of arsenic for plant uptake from the soils. Between 0.05 and 6.21% of the total soil arsenic were extracted using a single extraction test and a significant positive correlation between soil leachate pH and arsenic extractability (r = 0.70, p < 0.01) was observed. This suggested that soil pH might play a role in the bioavailability of arsenic.     

Spatial Distribution and Temporal Trend in Concentration of Carbofuran,Diazinon and Chlorpyrifos Ethyl Residues in Sediment and Water in Lake Naivasha,Kenya

Chlorpyrifos ethyl was found to be widely distributed in water and sediment in Lake Naivasha. Higher levels were reported in sediment (11.2–30.0 ng g⁻¹ dry weight (dw) in wet season than in dry season (4.7–17.4 ng g⁻¹ dw). The mean concentration of chlorpyrifos ethyl in water in wet season ranged between 8.8 and 26.6 μg L⁻¹ and decreased to between below detection limit to 14.0 μg L⁻¹ in dry season. On average, higher concentrations of chlorpyrifos ethyl were observed in sediment than water samples. Statistical analysis revealed a significant difference in concentration between the seasons, and a significant interaction between seasons and mean concentrations at p ≤ 0.05. However, levels of diazinon and carbofuran were below the detection limit in all the samples analyzed. Notably, levels of chlorpyrifos ethyl were higher than the maximum allowable limits (0.1 μg L⁻¹) recommended by European Union for drinking water and general water quality criterion for protection of freshwater water organisms (0.083 μg L⁻¹).     

Relationship of monocyte chemoattractant protein 1 (MCP-1) with insulin resistance and body mass index,but not with thermogenetic hormones in obesity

Monocyte chemoattractant protein 1 (MCP-1) has been implicated in the recruitment of monocytes to atheroma and of monocytes and macrophages to adipose tissue. The aim of the study was to examine whether MCP-1 levels are associated independently with the main thermogenetic hormones (serum TSH and thyroid hormones and 24-h urinary catecholamines) and insulin resistance in a population mainly represented by overweight and obese women. A cohort of 100 consecutive euthyroid women, aged 18–65 years, and with a wide range of BMI, was examined. Central fat accumulation (indirectly measured by waist circumference), fasting MCP-1 plasma levels, and TSH, FT₃, FT₄, insulin, glucose, and lipid (cholesterol, HDL-cholesterol and triglyceride) serum concentrations, and 24-h urinary catecholamines were measured. Insulin resistance was estimated by homeostasis model assessment (HOMA_IR). MCP-1 levels were directly associated with BMI (p < 0.001), waist circumference (p < 0.001), insulin (p < 0.001), HOMA_IR (p < 0.001), diastolic blood pressure (DBP) (p < 0.001), systolic blood pressure (SBP) (p < 0.001), triglycerides (TG) (p < 0.05), and 24-h urinary noradrenaline (p < 0.05), and negatively correlated with HDL-cholesterol (p < 0.01). When a multiple regression analysis was performed with MCP-1 as the dependent variable, and only parameters showing a significant univariate association with MCP-1 were considered as the independent variables, MCP-1 maintained an independent positive association with insulin (p < 0.01), and DBP (p < 0.05). When insulin was replaced by HOMA_IR in the regression analysis, MCP-1 maintained an independent positive association with HOMA_IR (p < 0.05), DBP (p < 0.05), and BMI (p < 0.05). In conclusion, this study suggests that insulin, BMI, and diastolic blood pressure cooperate independently in increasing MCP-1 levels, whereas thyroid hormones and catecholamines have no apparent influence on this chemokine.     

Sediment-Quality Assessment Using the Polychaete <Emphasis Type="Italic">Arenicola marina</Emphasis>: Contamination,Bioavailability, and Toxicity

The sediment quality of Cádiz Bay, Las Palmas de Gran Canaria (LPGC) Port, Santander Bay, Algeciras Bay, and Huelva Estuary (Spain) was evaluated by analysing a battery of biochemical biomarkers―activities of biotranformation enzymes ethoxyresorufin O-deethylase [EROD], dibenzylflourescein dealkylase [DBF], and glutathione S-transferase [GST]; activity of antioxidant enzyme glutathione reductase [GR]; and lipid peroxidation [LPO]―in the polychaete Arenicola marina after laboratory sediment exposure. Huelva Estuary polychaetes showed significantly (p < 0.05) enhanced LPO, GST, and EROD activities compared with control lugworms related to metals and presumably polychlorinated biphenyls. EROD activity significant (p < 0.05) induction was associated polycyclic aromatic hydrocarbons after Santander Bay sediment exposure. Nickel appeared to significantly (p < 0.05) induce GR activity and LPO in LPGC Port sediment–exposed organisms. DBF activity significantly (p < 0.05) increased in polychaetes exposed to sediments from sewage-contaminated areas. A. marina was sensitive at the biochemical level. Integration of sediment characterization and biomarker results allowed the identification of polluted sites as well as the cause of possible sediment toxicity.     

Concentrations of Selected Heavy Metals in Bones and Femoral Bone Structure of Bank (<Emphasis Type="Italic">Myodes glareolus</Emphasis>) and Common (<Emphasis Type="Italic">Microtus arvalis</Emphasis>) Voles from Different Polluted Biotopes in Slovakia

Concentrations of selected heavy metals in the femora and femoral bone structure of bank (Myodes glareolus) and common (Microtus arvalis) voles from different polluted biotopes in Slovakia (Kolíňany and Nováky sites) were investigated. Length, weight, and histological structure of vole bones were also analyzed. We observed higher concentrations of lead (Pb), iron (Fe), copper (Cu), and zinc (Zn) in the bones of both species from the Kolíňany site. Significant differences were observed in the concentration of Fe in bank and common voles (p < 0.05) and in the concentration of Zn (p < 0.05) in common voles. The animals from Nováky had higher concentrations of cadmium (Cd) and nickel (Ni) in their bones; however, the differences were not significant. The measured values for bone length and weight were higher in both species from Nováky (p < 0.05). We did not identify differences in qualitative histological characteristics of the femora between the voles (M. glareolus and M. arvalis separately) between the two biotopes. In addition, no statistically significant differences for any the measured variables of primary osteons’ vascular canals were observed. Correlation analysis in M. glareolus showed a strong positive relation between Cd and Ni (r = 0.52), Pb and bone weight (r = 0.53), Fe and bone weight (r = 0.52), and Fe and perimeter size of primary osteons’ vascular canals (r = 0.55). In common voles, a strong positive relation was found between Fe and Cu (r = 0.60) and between Fe and perimeter size of vascular canals of primary osteons (r = 0.55). Our results indicate that accumulation of some heavy metals is slightly increased in the femora of both species at Kolíňany.     

Macelignan: A New Modulator of P-Glycoprotein in Multidrug-Resistant Cancer Cells

The effect of macelignan, a phytoestrogen, on P-gp function was investigated using multidrug resistant cancer cells overexpressing P-gp (NCI/ADR-RES) and the fluorescent P-gp substrates, daunorubicin and rhodamine 123. Macelignan (40 μM) increased the cellular accumulation of daunorubicin by approximately threefold in NCI/ADR-RES cells, whereas it did not alter the cellular accumulation of daunorubicin in MCF-7/sensitive cells. Similarly, the presence of macelignan also enhanced significantly (P < 0.05) the cellular accumulation of rhodamine 123 in a concentration-dependent manner in NCI/ADR-RES cells. Furthermore, cancer cells were more susceptible to the cytotoxicity of vinblastine, a P-gp substrate, in the presence of macelignan. Those results suggest that macelignan has inhibitory effects on P-gp mediated cellular efflux. However, P-gp activity did not affect the cellular accumulation of macelignan itself. Taken all together, macelignan was identified as a novel inhibitor of P-gp activity and may be a promising lead compound for the rational design of more efficacious drugs to reverse multidrug resistance in cancer.     

Risk Assessment of Residual DDTs in Freshwater and Marine Fish Cultivated Around the Pearl River Delta, China

Six species of freshwater fish collected from 10 fishponds in Shunde and Zhongshan, China, four species of marine fishes collected from different mariculture farms [four in Hong Kong (Tung Lung Chau, Ma Wan, Cheung Chau and Kat O) and two in mainland China (Daya Bay and Shenzhen)] together with feed (both trash fish and commercial pellets) and sediment were analyzed for DDTs. Total DDTs in freshwater fish flesh decreased in the order of: carnivores [1742 μg/kg lipid weight (l.w.)] > herbivores (165 μg/kg, l.w.) > omnivores (42.5 μg/kg, l.w.), with the highest concentration detected in mandarin fish (Siniperca chuatsi) (2641 μg/kg, l.w.). For marine fish, snubnose pompano (Trachinotus blochii) and orange-spotted grouper (Epinephelus coioides) collected in Ma Wan contained elevated levels of total DDTs (2590 and 2034 μg/kg l.w., respectively). Trash fish used in both freshwater and marine fish farms contained significantly higher levels (86.5–641 μg/kg l.w.) (p < 0.05) of DDTs than in commercial pellets, but correlations between DDT levels in fish feed and muscle were not significant. The elevated biota-sediment accumulating factor for tilapia (Tilapia mossambicus) (24.1) indicated that accumulation of DDTs from sediment to the fish was evident. It can be concluded that trash fish should not be used for fish culture in order to lower the level of residual DDTs in fish muscle.     

Plasma homocysteine is adversely associated with glomerular filtration rate in asymptomatic black and white young adults: the Bogalusa heart study

That plasma homocysteine is elevated markedly in renal dysfunction is well recognized. But whether the increased homocysteine is an independent correlate of glomerular filtration rate, a marker of renal function, in asymptomatic younger individuals is not clear. The aim of this study was to determine the association between plasma homocysteine and renal function in a biracial (black–white) community-based cohort of asymptomatic young adults. Plasma homocysteine along with cardiovascular disease risk factor variables were measured in 805 white and 330 black subjects, ages 24–44 years, enrolled in the Bogalusa Heart Study. Modification of Diet in Renal Disease Study equation was used to calculate the estimated glomerular filtration rate (eGFR) from serum creatinine level. Males versus females showed higher homocysteine levels (8.83 ± 3.16 vs. 7.35 ± 2.84 μmol/L, p < 0.0001) and lower eGFR (99.1 ± 17.6 vs. 102.5 ± 21.0 mL/min/1.73 m², p = 0.024). Whites versus blacks had lower eGFR (97.3 ± 18.0 vs. 110.0 ± 20.6 mL/min/1.73 m², p < 0.0001). In a multivariate regression analysis that included age, race, sex, body mass index, blood pressure, lipoprotein variables, insulin resistance index and homocysteine, white race, age and homocysteine, in that order, were independently and negatively associated with eGFR. The odds ratio (95% confidence interval) of individuals in the homocysteine quintiles II, III, IV and V vs. I for having the risk of impaired eGFR defined as <10th percentile was 2.28 (0.95–5.50, p = 0.065), 2.97 (1.24–7.12, p = 0.015), 3.32 (1.45–7.60, p = 0.005) and 6.99 (3.06–15.94, p < 0.0001), respectively. Homocysteine is an independent correlate of renal function in asymptomatic black and white young adults.     

Determination of Five Phthalate Monoesters in Human Urine Using Gas Chromatography-Mass Spectrometry

We have developed a gas chromatography-mass spectrometry (GC–MS) method to determine five phthalate monoesters (monoethyl phthalate (MEP), mono-n-butyl phthalate (MBP), mono-(2-ethylhexyl) phthalate (MEHP), monoisononyl phthalate (MINP) and monobenzyl phthalate (MBz)) in human urine. Human urine samples were subjected to enzymatic deconjugation of the glucuronides followed by extraction with hexane. The extracted phthalate monoesters were methylated with diazomethane, purified on a Florisil column and then subjected to GC–MS analysis. The recoveries from urine spiked with five phthalate monoesters were 86.3%–119% with coefficients of variation of 0.6%–6.1%. We measured phthalate monoester levels in human urine by analyzing 36 samples from volunteers. MBP and MEP were detected in all samples, and their median concentrations were 60.0 and 10.7 ng/mL, respectively. MBzP and MEHP were found in 75% and 56% of samples, and their median concentrations were 10.9 and 5.75 ng/mL, respectively. MINPs were not detected in most samples (6% detectable). Women had significantly (p < 0.05) higher mean concentrations of MBP and MEP than men. The estimated daily exposure levels for the four parent phthalates excluding diisononyl phthalate ranged from 0.27 to 5.69 μg/kg/day (median).     

Assessment of Antifouling Biocides Contaminations in Maizuru Bay, Japan

The concentrations of organotin compounds in the aquatic environment of Maizuru Bay and their spatial distribution are discussed. The concentrations of tributyltin (TBT) compounds in water samples ranged from 0.001 to 0.002 μg l⁻¹, and monobutyltin compounds were the dominant species among the butyltin compounds. TBT concentrations in Maizuru Bay are low compared with other coastal waters of Japan. Drastic differences in TBT concentrations were not observed among the Maizuru Bay sites. Phenyltin compounds were not detected in the water samples. Concentrations of TBT and triphenyltin (TPT) in sediment from Maizuru Bay ranged, respectively, from 0.9 to 11 μg kg⁻¹, from 0.2 to 17 μg kg⁻¹ dry weight (dw). TBT concentrations in Maizuru Bay were lower than those in other coastal areas of Japan. TPT concentrations were greater than TBT concentrations in the fishing port. The concentrations of TBT and TPT in blue mussels (M. galloprovincialis) from Maizuru Bay were in the range of 2.4 to 9.3 μg kg⁻¹ and 0.2–13 μg kg⁻¹ wet weight (ww), respectively. A tolerable average residue level (TARL) was estimated at 74.8 μg kg⁻¹ from a tolerable daily intake (TDI) of 0.25 bis(tributyltin)oxide μg kg⁻¹ body weight day⁻¹. TBT concentrations detected in blue mussel samples were lower than the TARL values. The acceptable concentration of TPT, which were calculated using acceptable daily intake instead of TDI, was 127 μg kg⁻¹. Concentrations of TPT in blue mussel samples were also lower than the TARL. TBT compounds in blue mussel samples were at similar levels among the various sampling sites, indicating that TBT is not currently being used in ship hull paints; the ratios of degradation products of TBT and TPT were greater than those of the parent compounds. Concentrations of alternative biocides in water samples were also investigated in the bay. Although Sea-Nine 211, M1, and Pyrithiones were not detected, Diuron and Irgarol 1051 were detected at 0.010–0.257 and at 0.002–0.018 μg l⁻¹, respectively. Concentrations of Diuron were great in the shipping route and near the shipyard, whereas the concentration of Irgarol 1051 was great at the fishing port. Concentrations of Diuron and Irgarol 1051 in sediment from Maizuru Bay ranged, respectively, from <0.08 to 12, from <0.08 to 9.8 μg kg⁻¹ dw, respectively. Despite being a semi-enclosed bay, we found that sediment in Maizuru Bay is not contaminated by alternative biocides to the degree found in other coastal areas. Copper concentrations of sediment were at ordinary levels, and those of blue mussels were slightly lower than those reported previously in other coastal areas of Japan. In both the sediment and blue mussels, there was no correlation between the presence of copper and antifouling biocides.     

Effect of <Emphasis Type="Italic">Microcystis aeruginosa</Emphasis> on the rotifer <Emphasis Type="Italic">Brachionus calyciflorus</Emphasis> at different temperatures

Rotifers are one of the smallest metazoans. They serve as a model organism for ecotoxicological studies. More than 60% of the lakes in China are increasingly eutrophic and they are susceptible to blooms of Microcystis aeruginosa. We investigated the effects of M. aeruginosa on the survival and reproduction of Brachionus calyciflorus using the life table method at different temperatures. The findings showed that concentration of M. aeruginosa significantly affected the intrinsic rate of increase (r_m), net reproductive rate (R₀), average lifespan (L) and offspring number (p < 0.05). Temperature also significantly affected the generation time (T), average lifespan (L) and offspring number (p < 0.05). Moreover, the interaction between temperature and concentration had statistically significant effects on offspring number (p < 0.05). M. aeruginosa suppressed the survival and reproduction of B. calyciflorus, particularly at a concentration of 10⁶ cells/mL. The r_m values of the rotifers exposed at 10⁶ cells/mL decreased more than 200% compared with those of the control group. However, at a lower concentration, 10⁴ cells/mL, M. aeruginosa may supply appropriate nourishment to rotifers. In addition, at concentrations of 10⁵ and 10⁶ cells/mL, the inhibition of rotifers by M. aeruginosa heightened with increasing temperature.     

Evaluation of Pyrogallol-induced Cytotoxicity in Catalase-mutant Escherichia coli and Mutagenicity in Salmonella typhimurium

We evaluated pyrogallol cytotoxicity using Escherichia coli strains that express mammalian catalase gene derived from catalase mutant mice (Cs^b) and wild-type (Cs^a), and pyrogallol mutagenicity by Ames test. Pyrogallol was more toxic to Cs^b rather than to Cs^a (p < 0.05), while catalase, superoxide dismutase and ascorbic acid decrease the toxic effect. Pyrogallol also showed mutagenic effect (mutagenic index = 3.8 for 10 μmol pyrogallol/plate) while ascorbic acid (19.4% reduction, p < 0.001) and naringin (35.1% reduction, p < 0.001) played a protective role against it. Pyrogallol cytotoxicity and mutagenicity seem to be attributable, at least in part, to reactive oxygen species formation. This study also suggests that newly established catalase mutant E. coli is probably useful in hazard identification of oxidative chemicals.     

Residue,Temporal Trend and Half-Life Time of Selected Organochlorine Pesticides (OCPs) in Surface Soils from Bacninh,Vietnam

Selected organochlorine pesticides (p,p′-DDT, p,p′-DDE, p,p′-DDD, α,β,γ,δ-HCH) were analyzed in the surface soils of Bacninh, Viet Nam. Forty representative soil samples were collected from Bacninh town and three surrounding districts. ΣDDT concentrations ranged from <0.02 to 160.86 ng g⁻¹ dry weight, whereas ΣHCH concentrations ranged from <0.05 to 9.54 ng g⁻¹ dry weight. The half-life times of ΣDDT and ΣHCH are 6.7 and 4.9 years, respectively. The decreasing trends of ΣDDT and ΣHCH levels during the period from 1992 to 2006 are observed. There is no recent input of DDT and HCH in the study area.