Effect of arsenic (AsIII) on glutathione-dependent enzymes in liver and kidney of the freshwater fish Channa punctatus

The possible role of glutathione-dependent enzymes in the liver and kidney of the freshwater fish Channa punctatus has been studied after exposure to arsenic trioxide for different durations. Activities of glutathione-S-transferases, glutathione peroxidase, glutathione reductase, and catalase decreased in the liver and kidney as a result of the initial increase in arsenic concentration in the liver and kidney. However, during longer exposures, a decline in arsenic concentration corresponded with improved enzyme activity. Because arsenic manifests its toxicity by inducing oxidative stress, the antioxidant enzymes, especially the glutathione-dependent enzymes, play a protective role in arsenic toxicity.     

Diosmin exerts hepatoprotective and antihyperglycemic effects against sodium arsenite-induced toxicity through the modulation of oxidative stress and inflammation in mice

BackgroundChronic exposure to high concentrations of inorganic arsenic (NaAsO₂) in drinking water is related to an increase in the risk of liver toxicity and diabetes. Diosmin has various pharmacological properties, including antioxidant and anti-inflammatory properties. This study was designed to investigate the protective effects of diosmin on diabetes and hepatotoxicity caused by NaAsO₂.MethodsSixty male 8-week-old NMRI mice, weighing 25 ± 2 g, were randomly selected and put into six groups. The control (Group 1) was treated orally with distilled water, group 2 was treated with diosmin (100 mg/kg, p.o), group 3 received NaAsO₂ (10 mg/kg, p.o), and groups 4, 5, 6 received diosmin (25, 50, 100 mg/kg, p.o), respectively and NaAsO₂ (10 mg/kg, p.o). After 29 days, fasting blood sugar (FBS) measurement and glucose tolerance test were done. The mice were sacrificed on day 31, and blood and tissue (liver and pancreas) samples were taken. Then, serum and tissue samples were studied for biochemical and histological evaluations.ResultsThe results demonstrated that diosmin ameliorated glucose intolerance and decreased FBS compared to the NaAsO₂ group. Diosmin (50 and 100 mg/kg) improved the serum factors of liver function (alanine aminotransferase, aspartate transaminase, and alkaline phosphatase) in the groups receiving NaAsO₂. Moreover, increased levels of nitric oxide, tumor necrosis factor-alpha, and thiobarbituric acid reactive substances in liver tissue induced by NaAsO₂ were diminished by diosmin treatment. Administration of diosmin increased total thiol and enzymatic activities of catalase, superoxide dismutase, and glutathione peroxidase in liver tissue. Furthermore, treatment with diosmin reduced the increase in protein amount of Sirtuin 3 and nuclear factor kappa B in the groups receiving NaAsO₂. Also, the liver and pancreas histological lesions induced by NaAsO₂ were attenuated by diosmin treatment.ConclusionDiosmin has a preventive effect against hepatotoxicity and diabetes induced by NaAsO₂ in mice through its antioxidant and anti-inflammatory properties.     

Occupational exposure of foundry workers assessed by the urinary concentrations of 18 elements and arsenic species

BackgroundSome raw materials applied in Fe foundry industries may contain potentially toxic elements. Thus, foundry worker’s occupational exposure is a constant health concern.MethodIn this study, 194 urine samples from foundry workers were analyzed by inductively coupled plasma mass spectrometry for biomonitoring of Al, As, Ba, Cd, Co, Cr, Cs, Cu, Fe, I, Mn, Ni, Pb, Sb, Sn, Se, U and Zn. Moreover, arsenic speciation was performed in representative samples of production sector workers (group A) and administration sector workers (group B).ResultsConcentrations of As, Pb, Cd, Cu, Cs, I, Sb in urines from group A were higher than those found for group B. Samples of group A presented Cs, Ni, Mn, Pb, U and Zn concentrations higher than values reported for exposed workers assessed by other studies. Forty-four samples from group A exceed As-reference limits. Group A had approximately seven times more inorganic As (as arsenite) and 14 times more organic As (as dimethyl As) than group B. A statistically significant difference was observed in the elemental concentration in the workers' urine by the time in the function. Moreover, alcohol consumption is probably influencing the urine concentration of As, Ba, Cd, Co, Cu, Fe, I, Se and Zn.ConclusionThe monitored foundry workers are exposed to potentially toxic elements and more attention must be given to their health. Therefore, workplace safety conditions must be improved, and constant biomonitoring is necessary to ensure workers' health.     

Uptake and elimination of arsenobetaine by the mussel Mytilus edulis is related to salinity

The high concentrations of the naturally occurring arsenic compound arsenobetaine in marine animals, in comparison with freshwater animals, has led to the suggestion that salinity is a factor in its accumulation. In separate experiments, we investigated the uptake and elimination of arsenobetaine by the mussel Mytilus edulis when maintained under three salinity regimes (32, 24, and 16 practical salinity units). Both uptake and elimination of arsenobetaine depended on the salinity of the water in a manner leading to higher concentrations at the higher salinity. The data are consistent with a proposed role of arsenobetaine as an adventitiously acquired osmolyte, and readily explain field data for freshwater and marine animals.     

A study of lipid- and water-soluble arsenic species in liver of Northeast Arctic cod (Gadus morhua) containing high levels of total arsenic

In the present study liver samples (n = 26) of Northeast Arctic cod (Gadus morhua), ranging in total arsenic concentrations from 2.1 to 240 mg/kg liver wet weight (ww), were analysed for their content of total arsenic and arsenic species in the lipid-soluble and water-soluble fractions. The arsenic concentrations in the lipid fractions ranged from 1.8 to 16.4 mg As/kg oil of liver, and a linear correlation (r² = 0.80, p < 0.001) was observed between the total arsenic concentrations in liver and the total arsenic concentrations in the respective lipid fractions of the same livers. The relative proportion of arsenolipids was considerably lower in liver samples with high total arsenic levels (33–240 mg/kg ww), which contained from 3 to 7% of the total arsenic in the lipid-soluble fraction. In contrast liver samples with low arsenic concentrations (2.1–33 mg/kg ww) contained up to 50% of the total arsenic as lipid-soluble species. Arsenic speciation analysis of the lipid-soluble fractions of the livers, using reversed-phase high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC–ICP-MS), revealed the presence of several arsenolipids. Three major arsenic-containing hydrocarbons (C₁₇H₃₉AsO, C₁₉H₄₁AsO and C₂₃H₃₇AsO) and five arsenic-containing fatty acids (C₁₇H₃₅AsO₃, C₁₉H₃₉AO₃, C₁₉H₃₇AsO₃, C₂₃H₃₇AsO₃ and C₂₄H₃₇AsO₃) were identified using HPLC coupled to quadrupole time-of-flight mass spectrometry (qTOF-MS). Arsenobetaine was the major arsenic species in the water-soluble fraction of the livers, while dimethylarsinate, arsenocholine and inorganic arsenic were minor constituents. Inorganic arsenic accounted for less than 0.1% of the total arsenic in the liver samples.     

Microaerobic conditions are required for magnetite formation within aquaspirillum magnetotacticum

The amount of magnetite (Fe₃O₄) within magnetosomes of the microaerophilic bacterium Aquaspirillum magnetotacticum varies with oxygen and nitrogen supply. The development of optical methods for directly measuring cell magnetism in culture samples has enabled us to quantitate bacterial Fe₃O₄ yields. We measured final cell yields, average cell magnetic moments, and magnetosome yields of growing cells. Cultures were grown with NO₃‐, NH₄ ⁺, or both, in sealed, unshaken vials with initial headspace Po₂ values ranging from 0 (trace) to 21 kPa.

More than 50% of cells had detectable magnetosomes only when grown in the range of 0.5–5.0 kPa O₂. Optimum cell magnetism (and Fe₃O₄ formation) occurred under microaerobic conditions (initial headspace Po₂ of 0.5–1 kPa) regardless of the N source. At optimal conditions for Fe₃O₄ formation, denitrifying cultures produced more of this mineral than those growing with O₂ as the sole terminal electron acceptor. This suggests that competition for O₂ exists between processes involving respiratory electron disposal and Fe₃O₄ formation. Oxygen may also be required for Fe₃O₄ formation by other species of magnetotactic bacteria.

Bacterial Fe₃O₄ appears to persist in sediments after death and lysis of cells. The presence of bacterial Fe₃O₄ in the fossil and paleomagnetic records may be of use as a retrospective indicator of sedimentation that has occurred in microaerobic waters.     

Bacterial Communities in Bangladesh Aquifers Differing in Aqueous Arsenic Concentration

At Titas, Bangladesh, two aquifers of different arsenic concentrations and redox conditions were investigated to link variations in geochemistry to in situ bacterial diversity characterized by T-RFLP (terminal restriction fragment length polymorphism) and clone library analysis. While the shallow aquifer was characterized by reduced gray sediments with a higher share of easily mobilized sedimentary arsenic (2.6% was easily mobilized from 18 mg/kg of total arsenic available in sediments) and higher aqueous arsenic concentrations of 120 ± 6 μg/L (45% arsenite), the deeper aquifer consisted of brown oxidized sediments with lower aqueous arsenic concentrations, predominantly as arsenate (60 ± 6 μg/L; 3% arsenite) and a higher share of tightly bound arsenic (only 0.6% of 53 mg/kg total sorbed arsenic was easily mobilized). The bacterial communities of both aquifers were dominated by putative aerobic or denitrifying populations of Pseudomonas, Elizabethkingia and Pantoea. The shallow aquifer was more diverse in bacterial populations of aerobic, facultative and anaerobic bacteria, an observation which may be correlated to more variable geochemical conditions resulting in arsenic mobilization and re-sorption. The deeper aquifer showed higher abundance of aerobic bacterial populations including the presence of iron-oxidizing Sideroxydans possibly of importance for the sorption of arsenic on oxidized iron hydroxides. From the arsenic-affected shallow aquifer, As(III) oxidizing isolates of Comamonas and Microbacterium were obtained, which may provide information on suitable conditions for arsenic immobilization useful for future bioremediation efforts. Supplemental materials are available for this article. Go to the publisher’s online edition of Geomicrobiology Journal to view the free supplemental file.