Sha Li YU,Ling Fei XU,Jun Xia WU,Chen Juan YAO,Qiao Yun HU,Chun Xue ZHANG,Xin Yuan ZHAO,Hai Yan WEI,Xiao Ke WANG,Gang CHEN
Objective This study aimed to investigate the susceptibility of mice with streptozotocin(STZ)-induced diabetes mellitus (TIDM) to the uptake of pentavalent inorganic arsenic (iAs V ) and the possible molecular mechanism. Methods TIDM was induced in mice by STZ. TIDM and normal mice were treated with 15.0 mg/kg Na 2 HAsO 4 ·12H 2 O by intragastric administration. Then, the concentrations of arsenic in various tissues were measured by atomic fluorescence spectrometry. The gene expression levels of Pit1 and Pit2 were quantified by real-time RT-PCR, and their protein levels were detected by Western blotting in mouse heart, kidney, and liver tissues. Results The concentrations of arsenic in STZ-induced TIDM mouse tissues were higher at 2 h after intragastric administration of Na 2 HAsO 4 ·12H 2 O. Compared with the levels in normal mice, PIT1 and PIT2, which play a role in the uptake of iAs V , were upregulated in the livers and hearts of TIDM mice. PIT1 but not PIT2 was higher in TIDM mouse kidneys. The upregulation of Pit1 and Pit2 expression could be reversed by insulin treatment. Conclusion The increased uptake of iAs V in TIDM mouse tissues may be associated with increased PIT1 and/or PIT2 expression.
Yao Lixian,Huang Lianxi,Bai Cuihua,He Zhaohuan,Zhou Changmin
Roxarsone (ROX), a widely used feed organoarsenic additive, occurs as itself and its metabolites in animal manure that is commonly land used as fertilizer. Soil property impacts arsenic (As) speciation and bioavailability. Fourteen soils across China were used to conduct culture experiments to investigate As uptake by garland chrysanthemum ( ChrysanthemumL coronarium ), with the soils fertilized with chicken manure bearing ROX and its metabolites. The results show As(III) was the sole As form in garland chrysanthemum shoots, and As(III) and As(V) occurred in roots. Only inorganic As was detected in all soils when the plants were harvested. Stepwise regression analysis shows soil-exchangeable Ca predominated shoot As(III) concentration (shoot As(III) = 1.60030 soil Ca, R
2 = 0.8832***). Therefore, ROX is transferred into the human food chain finally as inorganic As in plants. Application of animal manure bearing ROX and its metabolites is not recommended in Ca-rich soils to avoid excess inorganic As dietary exposure.
Xue Liu,Jing–Wei Fu,Evandro Da Silva,Xiao–Xia Shi,Yue Cao,Bala Rathinasabapathi,Yanshan Chen,Lena Q. Ma
Arsenic (As) in soils is often adsorbed on Fe-(hydro)oxides surface, rendering them more resistant to dissolution, which is undesirable for phytoremediation of As-contaminated soils. Arsenic hyperaccumulator Pteris vittata prefers to grow in calcareous soils where available Fe and As are low. To elucidate its mechanisms of acquiring Fe and As from insoluble sources in soils, we investigated dissolution of goethite with pre-adsorbed arsenate (AsV; As-goethite) in presence of four organic ligands, including two root exudates (oxalate and phytate, dominant in P. vittata ) and two microbial siderophores (PG12-siderophore and desferrioxamine B). Their presence increased As solubilization from As-goethite from 0.03 to 0.27–5.33 mg L −1 compared to the control. The siderophore/phytate bi-ligand treatment released 7.42 mg L −1 soluble Fe, which was 1.2-fold that of the sum of siderophore and phytate, showing a synergy in promoting As-goethite dissolution. In the ligand-mineral-plant system, siderophore/phytate was most effective in releasing As and Fe from As-goethite. Moreover, the continuous plant uptake induced more As-goethite dissolution. The continued release of As and Fe significantly enhanced their plant uptake (from 0.01 to 0.43 mg plant −1 As and 2.7–14.8 mg plant −1 Fe) and plant growth (from 1.2 to 3.1 g plant −1 fw) in P. vittata . Since microbial siderophores and root exudates often coexist in soil rhizosphere, their synergy in enhancing dissolution of insoluble As-Fe minerals may play an important role in efficient phytoremediation of As-contaminated soils.
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