Arsenic tolerance

Bleeker, P.M., HakvoorL H.W., Bliek, M., Souer, E., and Schat, H. 2006. Enhanced arsenate reduction by aCDC25-like tyrosine phosphatase explains increased phytochelatin accumulation in arsenate-tolerant Holcus lanatus. Plant Journal, 45 917-29. 

Sundaram, S., Wu, S., Ma, L.Q., and Rathinasabapathi, B. 2009. Expression of aPteris vittata glutaredoxin PvGRX5 in transgenic Arabidopsis thaliana increases plant arsenic tolerance and decreases arsenic accumulation in the leaves. Plant, Cell and Environment (doi 10.1111/j.l365-3040.2009.01963.x). 

Kojima, C., Qu, W., Waalkes, M.P., Himeno, S., Sakurai, T. (2006). Chronic exposure to methylated arsenicals stimulates arsenic excretion pathways and induces arsenic tolerance in rat liver cells. Toxicol. Sci. 91 70-81. 

Li, Y., Dhankher, O.P., Carreira, L., Lee, D., Chen, A., Schroeder, J.I., Balish, R.S., Meagher, R.B. (2004). Overexpression of phytochelatin synthase in Arabidopsis leads to enhanced arsenic tolerance and cadmium hypersensitivity. Plant Cell Physiol. 45 1787-97. 

Maeda, S., Wada, H., Kuneda, K., Onoue, M., Ohki, A., Higashi, S., and Takeshita, T., 1987, Methylation of inorganic arsenic by arsenic-tolerant freshwater algae Journal -Organometallic, v. 1, p. 465-472. 

While these studies suggest a role of P-gp as a factor in the toxicity of inorganic chemicals, the study on rat liver cells106 suggests that different biochemical factors act cooperatively in conferring arsenic tolerance. A direct transport of heavy metals appears difficult to reconcile with current models of P-gp function. However, one could hypothesize that inorganic chemicals are transported as complexes with... 

Rocovich SE and West DA (1975) Arsenic tolerance in a population of the grass Andropogon scoparius Michx. Science 188 263-264. 

Meharg, A.A., Naylor, J., Macnair, M.R., 1994. Phosphorus nutrition of arsenate-tolerant and non-tolerant phenotypes of velvetgrass. J. Environ. Qual. 23, 234—238. 

Data on arsenic effects to soil biota and insects are limited. In general, soil microorganisms are capable of tolerating and metabolizing relatively high concentrations of arsenic. This adaptation seems usually to be due to decreased permeability of the microorganism to arsenic. Tolerant soil microbiota can withstand concentrations up to 1600.0 mg/kg however, growth and metabolism were reduced in sensitive species at 375.0 mg As/kg and, at 150.0-160.0 mg As/kg, soils were devoid of earthworms and showed diminished quantities... 

Although there is broad consensus that methylation acts as a detoxification mechanism in arsenic-tolerant bacteria, the physiological role of human AS3MT is less clear, because methylated trivalent arsenic species are potent careinogens. 

Porter, E. K. Peterson, P. J. 1977. Arsenic tolerance in grasses growing on mine waste. Environmental Pollution, 14, 255-265. 

Table 2 shows that the higher the As(V) level in acclimation, the higher is the arsenic accumulation by C. vulgaris. Foster [33] reported there to be relationship between the tolerance and bioaccumulation of copper ion by C. vulgaris (the same species as the above). According to his results, the nontolerant strain was four times as sensitive to the copper ion but accumulated 5 to 10 times more metal than the tolerant strain, which had been acclimated to copper ion in a copper-polluted environment. These results imply that tolerance to the copper ion is attributable to copper exclusion by the cell. On the other hand, the arsenic-tolerant strain accumulated more arsenic than the nonacclimated strain. Therefore, different mechanisms are likely to be involved in the tolerances of C. vulgaris to arsenic and copper. 

---