Association of serum microcystin levels with neurobehavior of school-age children in rural area of Southwest China: A cross-sectional study.

To investigate whether microcystin-LR (MC-LR) influences children's cognitive function and memory ability, we measured serum MC-LR and whole blood lead levels in 697 primary students, and collected their academic and neurobehavioral test scores. The median of serum MC-LR levels was 0.80 µg/L (the value below the limit of detection to 1.67 µg/L). The shapes of the associations of serum MC-LR levels (cut-point: 0.95 µg/L) with scores on academic achievements, digit symbol substitution test and long-term memory test were parabolic curves. Logistic regression analysis showed that MC-LR at concentrations of 0.80-0.95 µg/L was associated with the increased probability of higher achievements on academic achievements [odds ratio (OR) = 2.20, 95% confidence interval (CI): 1.28-3.79], and also with scores on digit symbol substitution test (OR = 1.73, 95% CI: 1.05-2.86), overall memory quotient (OR = 2.27, 95% CI: 1.21-4.26), long-term memory (OR = 1.85, 95% CI: 1.01-3.38) and short-term memory (OR = 2.13, 95% CI: 1.14-3.98) after adjustment for confounding factors. Antagonism of MC-LR and lead on long-term memory was observed (synergism index = 0.15, 95% CI: 0.03-0.74). In conclusion, serum MC-LR at concentrations of 0.80-0.95 µg/L was positively associated with higher scores on cognitive and neurobehavioral tests, and antagonism between MC-LR at concentrations of 0.80-1.67 µg/L and lead exposure was obviously observed on long-term memory in children. Concerning that MC-LR is a neurotoxin at high doses, our observation is interesting and need further investigation.

Consumption of Very Low Mineral Water Is Associated with Lower Bone Mineral Content in Children.

BACKGROUND: Our previous study found that consumption of very low mineral drinking water may retard height development in schoolchildren; however, its association with bone modeling remained unknown. OBJECTIVES: The aim of this study was to investigate the influence of very low mineral water on biomarkers of bone modeling in children. METHODS: A retrospective cohort study was conducted among 2 groups of 10-13-y-old children who had consumed drinking water with normal mineral contents (conductivity 345 µs/cm, the NW group including 119 boys and 110 girls) or very low mineral contents (conductivity 40.0 µs/cm, the VLW group including 223 boys and 208 girls) in school for 4 y. Differences in daily total mineral intakes, developmental parameters, serum biomarkers of osteoblast activity, and bone formation and resorption between the 2 groups were analyzed with independent t test and chi-square test. Associations of developmental parameters and serum biomarkers with Ca intake from drinking water were analyzed with multiple linear regression and binary logistic regression. RESULTS: Compared with the NW group, the VLW group had lower daily Ca intake, height increase, bone mineral content (BMC), osteoblast activity [serum bone alkaline phosphatase (BALP)] (means ± SDs: 433 ± 131 mg, 16.6 ± 8.27 cm, 1.92 ± 0.431 kg, and 9.28 ± 1.42 µg/L compared with 497 ± 155 mg, 22.3 ± 8.45 cm, 2.14 ± 0.354 kg, and 11.0 ± 0.823 µg/L, respectively, P < 0.001), and higher bone resorption [serum crosslinked C-telopeptide of type I collagen (CTX), mean ± SD: 142 ± 46.9 nmol/L compared with 130 ± 40.6 nmol/L, P = 0.001). Ca intake from drinking water was positively associated with height increase, BMC, and BALP (ß: 0.0667, 95% CI: 0.0540, 0.0793; ß: 3.22, 95% CI: 2.37, 4.08; and ß: 23.9, 95% CI: 20.6, 27.2), respectively, P < 0.001), and was negatively associated with CTX (ß: -0.206, 95% CI:-0.321, -0.0904, P < 0.001). CONCLUSIONS: These changes suggested that consumption of very low mineral water may be associated with osteoblast inhibition, bone resorption activation, bone mineral reduction, and height development retardation. The health risk of consuming very low mineral water should be considered in children.

Chronic Microcystin-LR Exposure Induces Hepatocarcinogenesis via Increased Gankyrin in Vitro and in Vivo.

BACKGROUND/AIMS: Our recent study indicated that the serum microcystin-LR (MC-LR) level is positively linked to the risk of human hepatocellular carcinoma (HCC). Gankyrin is over-expressed in cancers and mediates oncogenesis; however, whether MC-LR induces tumor formation and the role of gankyrin in this process is unclear. METHODS: We induced malignant transformation of L02 liver cells via 35 passages with exposure to 1, 10, or 100 nM MC-LR. Wound healing, plate and soft agar colony counts, and nude mice tumor formation were used to evaluate the tumorigenic phenotype of MC-LR-treated cells. Silencing gankyrin was used to confirm its function. We established a 35-week MC-LR exposure rat model by twice weekly intraperitoneal injection with 10 µg/kg body weight. In addition, 96 HCC patients were tested for tumor tissue gankyrin expression and serum MC-LR levels. RESULTS: Chronic low-dose MC-LR exposure increased proliferation, mobility, clone and tumor formation abilities of L02 cells as a result of gankyrin activation, while silencing gankyrin inhibited the carcinogenic phenotype of MC-LR-treated cells. MC-LR also induced neoplastic liver lesions in Sprague-Dawley rats due to up-regulated gankyrin. Furthermore, a trend of increased gankyrin was observed in humans exposed to MC-LR. CONCLUSION: These results suggest that MC-LR induces hepatocarcinogenesis in vitro and in vivo by increasing gankyrin levels, providing new insight into MC-LR carcinogenicity studies.

Serum microcystin levels positively linked with risk of hepatocellular carcinoma: A case-control study in southwest China.

Microcystins have been reported to be carcinogenic by animal and cell experimentation, but there are no data on the linkage between serum microcystins and hepatocellular carcinoma (HCC) risk in humans. We conducted a clinical case-control study to investigate the association between serum microcystins and HCC risk after controlling several known risk factors, such as hepatitis B virus, alcohol, and aflatoxin. From December 2013 to May 2016, 214 patients newly diagnosed with HCC along with 214 controls (frequency-matched by age and sex) were recruited from three hospitals in Chongqing, southwest China. Basic information on lifestyle and history of disease was obtained by questionnaire. Blood samples were collected and analyzed for serum microcystin-LR (MC-LR) and aflatoxin-albumin adduct by enzyme-linked immunosorbent assay and for hepatitis B surface antigen status by chemiluminescence assay. Binary logistic regression analyses were performed to assess the independent effects of MC-LR and its joint effects with other factors on HCC risk. The adjusted odds ratio for HCC risk by serum MC-LR was 2.9 (95% confidence interval [CI], 1.5-5.5) in all patients. Notably, a clear relationship between increased MC-LR level (Q2, Q3, and Q4) and HCC risk was observed with elevated adjusted odds ratios (1.3, 2.6, and 4.0, respectively). Positive interactions with the additive model were investigated between MC-LR and hepatitis B virus infection (synergism index = 3.0; 95% CI, 2.0-4.5) and between MC-LR and alcohol (synergism index = 4.0; 95% CI, 1.7-9.5), while a negative interaction was found between MC-LR and aflatoxin (synergism index = 0.4; 95% CI, 0.3-0.7). Additionally, serum MC-LR was significantly associated with tumor differentiation (r = -0.228, P < 0.001). CONCLUSION: We provide evidence that serum MC-LR was an independent risk factor for HCC in humans, with an obvious positive interaction with hepatitis B virus and alcohol but a negative interaction with aflatoxin. (Hepatology 2017;66:1519-1528).

Upregulated long non-coding RNA LOC90784 promotes cell proliferation and invasion and is associated with poor clinical features in HCC.

A growing amount of literature has indicated that long non-coding RNAs (lncRNAs) are important factors in hepatocellular carcinoma (HCC) progression. However, the significance of lncRNAs in the progression and prognosis of liver cancer is largely unknown. In the present study, upregulated lncRNA LOC90784 was identified through integrative analysis of GSE58043 and GSE55191. Furthermore, associations between LOC90784 expression and the clinicopathological characteristics of patients were analyzed with a validated cohort 1 and the Cancer Genome Atlas (TCGA) cohort 2. We investigated the mechanisms by which this highly expressed lncRNA promotes HCC proliferation, invasion and migration via qRT-PCR, fluorescence in situ hybridization (FISH) staining, siRNA transfection, cell proliferation assays, Transwell and colony formation assays, flow cytometry analysis and Western blot. The results showed that LOC90784 expression levels were significantly higher in HCC cell lines and tissues and mainly localized in the cytoplasm. Knockdown of lncRNA LOC90784 expression inhibited proliferation and induced apoptosis and cell cycle arrest by promoting Bax and repressing CDK4 and Cyclin D1 protein expression; it also inhibited invasion and migration by repressing MMP2 and MMP9 expression in HCC cells. LOC90784 overexpression was associated with poor clinical features in the two cohorts and poor overall survival rates in HCC patients with clear resection margins (R0) in cohort 2. These results indicated that LOC90784 upregulation may be a critical oncogene and potential new biomarker in HCC.

Environmental Microcystin Exposure Increases Liver Injury Risk Induced by Hepatitis B Virus Combined with Aflatoxin: A Cross-Sectional Study in Southwest China.

Three liver hazards, two confirmed-hepatitis B virus (HBV) and aflatoxin (AFB), and one rarely studied in populations-microcystin (MC), simultaneously exist in tropical and humid areas; however, there are no epidemiological data on their risks in the same population. We conducted a community-based cross-sectional survey among 5493 adults in two rural towns and statistically analyzed the comparative and combinative effects of the three factors after detecting HBsAg and HBV DNA titers, determining estimated daily intakes (EDIs) of AFB1 and MC-LR and testing serum AST and ALT as liver injury markers for each participant. We observed a HBsAg(+) rate of 7.6%, a relatively high AFB1 exposure level (mean EDIAFB1 = 471.30 ng/d), and a relatively low MC-LR exposure level (mean EDIMC-LR = 228.25 ng/d). ORs for abnormal AST (2.42, 95%CI = 1.69-3.45) and ALT (2.87, 95%CI = 1.91-4.29) increased in HBV infections compared with HBV-unexposed participants but did not increase in participants with separate or combined exposure to AFB1 and MC-LR (EDIs ≥ mean). Meanwhile, after adjustment for confounding factors, means of AST and ALT and ORs of abnormal AST and ALT were successively elevated after exposure to HBV, HBV&AFB1 (or HBV&MC-LR), and HBV&AFB1&MC-LR, especially in the group with detectable HBV DNA (AST: OR = 11.38, 95%CI = 3.91-33.17; ALT: OR = 17.09, 95%CI = 5.36-54.53). Notably, ORs for abnormal AST and ALT in the HBV exposed group were not significantly different from those in HBV&AFB1 or in the HBV&MC-LR exposed group but were significantly higher in the HBV&AFB1&MC-LR exposed group (P = 0.029 and P = 0.037, respectively). Our study indicated that microcystin may have the potential to increase the risk of liver injury induced by combined exposure to HBV and aflatoxin. However, in consideration of the uncertainties in the detection of the toxins and evaluation of the EDIs, more epidemiological data are expected to determine the increasing toxic effects of microcystins.

Determination of Environmental Exposure to Microcystin and Aflatoxin as a Risk for Renal Function Based on 5493 Rural People in Southwest China.

Although the nephrotoxicity of microcystin and aflatoxin has been observed in animal and clinical cases, few population data are available. We conducted a cross-sectional study in Southwest China to investigate the association of renal function indicators (RFIs, including BUN, SCr, and eGFR) with exposure to microcystin and aflatoxin in 5493 members of the general population. Microcystin-LR levels in water and aquatic products and aflatoxin B1 levels in daily foods were measured by ELISA, and individual estimated daily intake (EDI) was assessed on the basis of the measurement and questionnaire. We found that participants with abnormal RFIs had a much higher mean level of microcystin-LR EDI than those with normal RFIs and that there was a significant increasing trend for abnormal rates and odds ratios of RFIs with increasing microcystin-LR EDI quartiles (p for trend = 0.000). Compared with the lowest quartile of microcystin-LR exposure, those in the highest quartile had significantly higher risks of abnormal BUN (OR = 1.80, 95% CI = 1.34-2.42), SCr (OR = 4.58, 95% CI = 2.92-7.21), and eGFR (OR = 4.41, 95% CI = 2.55-7.63), respectively, but no higher risk was found in subjects with higher AFB1 exposure. After adjustment for confounding factors, risk associations with microcystin-LR persisted. Consequently, our results suggest that microcystin, rather than aflatoxin, might be one important risk of renal-function impairment.

[Pay attention to the human health risk of drinking low mineral water].

The consumption of low mineral drinking water has been increasing around the world with the shortage of water resources and the development of advanced water treatment technologies. Evidences from systematic document reviews, ecological epidemiological observations, and experimental drinking water intervention studies indicate that lack of minerals in drinking water may cause direct or indirect harm to human health, among which, the associations of magnesium in water with cardiovascular disease, as well as calcium in water with osteoporosis, are well proved by sufficient evidence. This article points out that it is urgent to pay more attention to the issues about establishment of health risk evaluation system on susceptible consuming population, establishment of lab evaluation system on water quality and health effect for non-traditional drinking water, and program of safety mineralization for demineralized or desalinated water and so on.

Long-Term Consumption of Purified Water Altered Amino Acid, Fatty Acid and Energy Metabolism in Livers of Rats.

The consumption of low-mineral water has been increasing worldwide. Drinking low-mineral water is associated with cardiovascular disease, osteopenia, and certain neurodegenerative diseases. However, the specific mechanism remains unclear. The liver metabolic alterations in rats induced by drinking purified water for 3 months were investigated with a metabolomics-based strategy. Compared with the tap water group, 74 metabolites were significantly changed in the purified water group (6 increased and 68 decreased), including 29 amino acids, 11 carbohydrates, 10 fatty acids, 7 short chain fatty acids (SCFAs), and 17 other biomolecules. Eight metabolic pathways were significantly changed, namely aminoacyl-tRNA biosynthesis; nitrogen metabolism; alanine, aspartate and glutamate metabolism; arginine and proline metabolism; histidine metabolism; biosynthesis of unsaturated fatty acids; butanoate metabolism; and glycine, serine and threonine metabolism. These changes suggested that consumption of purified water induced negative nitrogen balance, reduced expression of some polyunsaturated fatty acids and SCFAs, and disturbed energy metabolism in rats. These metabolic disturbances may contribute to low-mineral-water-associated health risks. The health risk of consuming low-mineral water requires attention.

Occurrence and infection risk of waterborne pathogens in Wanzhou watershed of the Three Gorges Reservoir, China.

The Three Gorges Reservoir (TGR), formed by China's Yangtze Three Gorges Project, is the largest lake in the world, but there is too little information available about fecal contamination and waterborne pathogen impacts on this aquatic ecosystem. During two successive 1-year study periods (July 2009 to July 2011), the water quality in Wanzhou watershed of the TGR was tested with regard to the presence of fecal indicators and pathogens. According to Chinese and World Health Organization water quality standards, water quality in the mainstream was good but poor in backwater areas. Salmonella, Enterohemorrhagic Escherichia coli (EHEC), Giardia and Cryptosporidium were detected in the watershed. Prevalence and concentrations of the pathogens in the mainstream were lower than those in backwater areas. The estimated risk of infection with Salmonella, EHEC, Cryptosporidium, and Giardia per exposure event ranged from 2.9 x 10(-7) to 1.68 x 10(-5), 7.04 x 10(-10) to 2.36 x 10(-7), 5.39 x 10(-6) to 1.25 x 10(-4) and 0 to 1.2 x 10(-3), respectively, for occupational divers and recreational swimmers exposed to the waters. The estimated risk of infection at exposure to the 95% upper confidence limit concentrations of Salmonella, Cryptosporidium and Giardia may be up to 2.62 x 10(-5), 2.55 x 10(-4) and 2.86 x 10(-3), respectively. This study provides useful information for the residents, health care workers and managers to improve the safety of surface water and reduce the risk of fecal contamination in the TGR.

XRCC1 Arg280His polymorphism and glioma risk: A meta-analysis involving 1439 cases and 2564 controls.

OBJECTIVES: Previous reports indicated that XRCC1 Arg280His polymorphism might be a possible risk factor for several cancers. Published studies on the association of XRCC1 Arg280His polymorphisms with glioma risk have yielded controversial results. The present study aimed to derive a more precise estimation of the relationship. METHODOLOGY: Meta-analyses assessing the association of XRCC1 Arg280His variation with glioma were conducted and subgroup analyses on ethnicity and source of controls were further performed. Eligible studies for the period up to May 2012 were identified. RESULTS: A total of four case-control studies comprising 1439 cases and 2564 controls were selected for analysis. The overall data indicated no significant association of XRCC1 Arg280His polymorphism with glioma risk (His vs Arg: OR=1.05; 95%CI=0.88-1.25; His/His vs Arg/Arg: OR=1.42; 95%CI=0.87-2.29; dominant model: OR=1.00; 95%CI=0.82-1.22; recessive model: OR=1.41; 95%CI=0.88-2.25). Likewise, in the subgroup analysis regarding ethnicity and source of controls, no associations were observed. CONCLUSION: The results of the present study failed to suggest an association of XRCC1 Arg280His polymorphism with glioma risk. Further large and well-designed studies are needed to confirm this conclusion.

Consumption of very low-mineral water may threaten cardiovascular health by increasing homocysteine in children.

Introduction: Homocysteine (Hcy) is a critical factor for cardiovascular injury, and the elevation of Hcy in children will inevitably increase the risk of cardiovascular disease in adulthood. This study explored the effect of very low-mineral water on children's Hcy and cardiovascular health. Materials and methods: This was a retrospective cohort study that recruited two groups of 10-13-year-old children who had consumed direct drinking water (DDW) in school for 4 years. The control group (NW) (119 boys, 110 girls) consumed normal DDW (conductivity 345 µs/cm). The very low-mineral water consumption group (VLW) (223 boys, 208 girls) consumed very low-mineral DDW (conductivity 40.0 µs/cm). Serum Hcy, Hcy metabolites, cofactors of Hcy metabolism, and cardiovascular biomarkers were assessed and standardized by age- and sex-specific Z-scores, and the differences between the two groups were analyzed with independent t-test. The relationships between Hcy metabolism biomarkers and key factors, cardiovascular biomarkers, serum Ca, and mineral intake were analyzed with linear regression. Results: Compared with the NW group, the VLW group had significantly higher serum Hcy, Apo-B, Apo-B/A1, and oxLDL, and lower serum 1,25,(OH)2D3, vitamin B6 and B12, 5-methyltetrahydrofolate, and Apo-A1. Serum Hcy was positively associated with serum Apo-B and Apo-B/A1, and negatively associated with Ca intake from water and serum 1,25,(OH)2D3. Conclusion: This study suggested that drinking very low-mineral water may increase Hcy level and oxidative stress, worsen lipid profile, and threaten the cardiovascular system in children. Reducing 1,25,(OH)2D3, and disordering of calcium metabolism might play important roles. This study first established an association between demineralized drinking water and cardiovascular health in children, suggesting a new environmental concern risk to cardiovascular health.

Microcystin-leucine-arginine impairs bone microstructure and biomechanics by activating osteoimmune response and inhibiting osteoblasts maturation in developing rats.

Microcystin-LR (MC-LR) affects bone health in adult mice via osteo-immunomodulation. However, its effect on osteoblasts and bone development is unclear. This study investigated the effect of MC-LR on bone osteoimmune and osteoblasts in the developing period. 18 Four-week-old male Sprague Dawley rats were divided into two groups (n = 9 per group) and exposed to 0 (control) and 1 µg/kg b.w. MC-LR (exposure) by intraperitoneal injection for four weeks. The heart blood was collected for serological examination, and the femur for morphological, histopathological, and biomechanical analysis. MC-LR exposure significantly weakened bone microstructures (bone volume, bone volume/total volume, bone trabecular number, connectivity density) and biomechanics (maximum loads and maximum deflection) (P < 0.05). Besides, MC-LR decreased serum procollagen type І car-boxy-terminal propeptide, osteocalcin, bone morphogenetic protein-2, osteoprotegerin, and receptor activator of nuclear factor κB ligand, while elevating osteoclasts number, matrix metalloproteinase-9, ß-catenin, Runt-related transcription factor 2, and osterix in bone, and bone alkaline phosphate, C-terminal cross-linked telopeptide of type-I collagen, tartrate-resistant acid phosphatase-5b in serum (P < 0.05). Moreover, MC-LR increased CD4+ T-cells, CD4+/CD8+, M1 and M2 macrophages, and cells apoptosis in the bone marrow, interleukin-6, interleukin-17, and tumor necrosis factor-α in serum, decreased serum interleukin-10 (P < 0.05). Overall, MC-LR can promote bone resorption by activating osteoclasts via osteoimmunology, which may involve macrophages besides lymphocytes. MC-LR may inhibit bone formation by stopping the osteoblasts at an immature stage. Thus, MC-LR weakened bone microstructure and biomechanics in developing period. Its risk on bone development needs further study.

Identification of microRNAs changed in the neonatal lungs in response to hyperoxia exposure.

Bronchopulmonary dysplasia (BPD) is a multifactorial chronic lung disease of premature infants. BPD can be attributed to the dysregulation of normal lung development due to ventilation and oxygen toxicity, resulting in pathologic complications of impaired alveolarization and vascularization. MicroRNAs (miRNA) are small noncoding RNAs that regulate gene expression posttranscriptionally and are implicated in diverse biological processes and diseases. The objectives of this study are to identify the changed miRNAs and their target genes in neonatal rat lungs in response to hyperoxia exposure. Using miRNA microarray and real-time PCR analyses, we found downregulation of five miRNAs, miR-342, miR-335, miR-150, miR-126*, and miR-151*, and upregulation of two miRNAs, miR-21 and miR-34a. Some of these miRNAs had the highest expression during embryonic and early postnatal development. DNA microarray analysis yielded several genes with conserved binding sites for these altered miRNAs. Glycoprotein nonmetastatic melanoma protein b (GPNMB) was experimentally verified as a target of miR-150. In summary, we identified seven miRNAs that were changed in hyperoxia-exposed neonatal lungs. These results provide a basis for deciphering the mechanisms involved in the spatial and temporal regulation of proteins that contribute to the pathogenesis of BPD.

Drinking Natural Mineral Water Maintains Bone Health in Young Rats With Metabolic Acidosis.

Introduction: Metabolic acidosis affects bone health. It remains unclear whether drinking natural mineral water is better for maintaining bone health in the youth with metabolic acidosis. Materials and Methods: Sixty young female rats (3-weeks-old) were randomly divided into three groups and drank purified water (PW, as control), bicarbonate-rich natural mineral water (Bic-NMW), or sulfate-rich natural mineral water (Sul-NMW), which, respectively, contained calcium (0.17, 155, and 175 mg/L), bicarbonate (0.1360, and 139 mg/L) and sulfate (0, 35.6, and 532 mg/L), for 16 weeks. In the last 3 weeks, metabolic acidosis was induced in 10 rats per group by adding NH4Cl (0.28 mM) to drinking water. The rats' blood, urine, and femur were collected for assessing acid-base status, calcium metabolism, bone microstructure, and strength. The difference between the three groups was determined using one-way ANOVA followed by the Student-Newman-Keuls test or Dunnett's T3 test. Results: Compared with the PW rats, the Bic-NMW rats and the Sul-NMW rats had less urine net acid excretion (-1.51, 0.20 vs. 10.77, EQ/L), higher bone mineral density (442.50, 407.49 vs. 373.28, mg/mm3), growth cartilage width (271.83, 283.83 vs. 233.27, µm) and cortical trabecular area (9.33, 9.55 vs. 5.05, mm2), and smaller cortical marrow cavity area (5.40, 5.49 vs. 7.27, mm2) in the femur (P < 0.05). Besides, the Bic-NMW rats had less serum calcium (2.53 vs. 2.68, mmol/L) and C-terminal cross-linked telopeptide of type-I collagen (1.35 vs. 1.93, ng/mL), and higher serum calcitonin (0.61 vs. 0.39, µg/L), femoral trabecular thickness (0.10 vs. 0.09, µm), bone volume/total volume (0.42 vs. 0.34, %), cortical bone area (15.91 vs. 12.80, mm2), and ultimate stress (35.12 vs. 29.32, MPa) (P < 0.05). The Sul-NMW rats had more osteoclasts (22.50 vs. 11.54, cells/field) (P < 0.05). Conclusions: Drinking natural mineral water, especially bicarbonate-rich natural mineral water, is effective in improving bone health in young rats with metabolic acidosis. These benefits include maintaining bone mineral density, and improving bone microstructure and biomechanical properties via moderating metabolic acidosis.

Reproductive toxicity in male mice caused by organic extracts in tap water from the Jialing River in Chongqing, China.

BACKGROUND: Recently, male reproductive disturbances caused by organic pollutants have aroused particular public concern about the safety of drinking water. The aim of this study was to investigate the toxicity of organic extracts (OE) in tap water from the source of the Jialing River in China on the reproductive system of male mice. METHODS: Kunming male mice were randomly divided into four groups, which included a solvent control (dimethylsulfoxide), a low-, mid-, and high-dose of OE (12.5, 25, and 50 l/kg bw/day, respectively) treated groups. Mice were administered intraperitoneal injections of OE at different doses for five consecutive days. On the 15th day, after treatments, the mice were sacrificed. RESULTS: The results showed that the number of epididymal sperm in the high OE group was decreased significantly (p<0.05); however, the frequency of sperm abnormalities in all treated groups were increased significantly (p<0.05). In addition, serum testosterone and follicle-stimulating hormone levels in the treated groups were also decreased significantly (p<0.05), and mid- and high-doses of OE resulted in a significant decrease in the activity of acid phosphatase and increased activity of γ-glutamyl transpeptidase (p<0.05). Histological changes were observed in the mid- and high-dose OE-treated groups. CONCLUSIONS: The findings of this study suggest that mid and high doses of OE could disturb the male reproductive system in mice. The potential adverse effects of these compounds on the male reproductive system are worthy of further study.

Seasonal variations of dissolved inorganic nutrients transported to the Linjiang Bay of the Three Gorges Reservoir, China.

Field surveys were carried out from January 2007 to December 2008 to investigate seasonal variations of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) transported to the Linjiang Bay of the Three Gorges Reservoir, China. The results revealed that both DIN and DIP exhibited large seasonal variability. DIN (dominated by NH4-N) concentrations were drastically higher in the dry season than those in the rainy season, and the same seasonal patterns of DIP concentrations and DIN and DIP fluxes were observed but inverse to that of DIN concentrations. The interannual variation in DIN fluxes descended by 28.2% from 2007 to 2008, while DIP fluxes increased by 40.9%, which were closely constant with interannual changes in DIN and DIP concentrations, respectively. The study indicated that nutrient fluxes (DIN and DIP) were strongly correlated with both nutrient concentrations and river discharge, and the Linjiang Bay received approximately 3,416×10(3) kg DIN and 324×10(3) kg DIP every year. In addition, DIN mainly originated from point sources, but DIP originated from non-point sources. It is shown that to control point source pollution is the most effective step for water quality improvement and reducing nutrient loading inputs in the Linjiang Bay.

Identification of microcystins contamination in surface water samples from the Three Gorges Reservoir, China.

Physicochemical and biological parameters related to water quality and microcystins (MCs) contamination in aquatic environment of the Three Gorges Reservoir were investigated in August 2004 and January 2005. A solid-phase extraction method and an HPLC equipped with photodiode array were used for MC-LR detection. A quantitative analysis showed the total MC-LR concentrations of water samples ranged from non-detectable to 0.57 µg L⁻¹ among the seven sampling sites. The highest MC-LR concentration was found at sampling site G (Wushan), which was followed by F (Kaixian), E (Wanzhou), D (Fuling), C (Cuntan), and A (Daxigou). The correlation analysis showed the MC-LR concentration was positively correlated with chlorophyll-a concentration. This result suggests that MC concentration in water can be indirectly estimated by analyzing the chlorophyll-a concentration. Overall, the results of this study suggest that more importance should be placed on monitoring of MC contamination and water quality in the Three Gorges Reservoir to ensure drinking water safety and reduce the potential exposure of people to these health hazards.

[Comparison of organic component and di-n-butyl phthalate between human milk and cow milk products].

OBJECTIVE: To explore types of organic components and pollution level of di-n-butyl phthalate (DBP) between human milk and cow milk products. METHODS: Forty healthy postpartum women with an average age of (27.44 ± 3.43) years old were selected, and a 5 ml sample of breast milk were collected. Four different brands of fresh cow milk and 1 brand of milk powder were randomly selected in the market. A total of 15 samples were collected with 3 from each brand, and the qualitative analysis of types of organic components and quantitative analysis of DBP were conducted by gas-chromatography and mass-spectrometry (GC/MS) method. RESULTS: A total of 176 different types of organic components were detected in 40 samples of human milk (averaged at (10.58 ± 4.16) types per sample); 37 different types were detected in 12 samples of fresh cow milk (averaged at (8.67 ± 1.61) types per sample); while 31 types of organic components were detected in 3 samples of milk powder (averaged at (12.67 ± 0.58) types per sample). It was obvious that the types of organic components in milk powder were significantly higher than the other two groups (t = 2.09, 4.00, P < 0.05). The most frequent organic component in human milk and cow milk was 9-octadecenoic acid (45.00% (18/40) in human milk; 53.33% (8/15) in cow milk). DBP concentrations were (57.78 ± 35.42) µg/L, (20.76 ± 6.60) µg/L and (0.45 ± 0.05) mg/kg (equal to (66.78 ± 7.60) µg/L) in human milk, fresh cow milk and milk powder, respectively. The DBP concentration in fresh cow milk was significantly lower than those in human milk and milk powder (t = 37.02, 46.02, P < 0.05). CONCLUSION: Both human milk and cow milk contain different types of organic pollutants, some of which have toxic effects on reproduction and human development.

Involvement of recF in 254 nm ultraviolet radiation resistance in Deinococcus radiodurans and Escherichia coli.

recF is a critical gene involved in the RecFOR pathway of DNA repair in Deinococcus radiodurans (D. radiodurans). To investigate the role of recF in UV-C radiation resistance, we generated the recF-deficient D. radiodurans strain R1, expressed recF in Escherichia coli (E. coli) BL21 cells, and compared the ability of each to resist UV-C radiation by F (10), inactivation constant (IC), and extrapolation number (N). The mutation of recF in D. radiodurans R1 resulted in characteristic slow growth and dramatic sensitivity to UV-C irradiation. Transformation of recF into E. coli BL21 cells resulted in increased UV-C resistance compared to untransformed E. coli BL21 cells. These results suggested that recF is needed for the replication of D. radiodurans. Furthermore, as a part of the RecFOR pathway in D. radiodurans, disruption of recF could dramatically decrease the UV-C resistance of D. radiodurans and recF could increase the UV-C resistance of E. coli BL21 cells.