Selenium tolerance

LeDuc, D. L., Tarun, A. S., Montes-Bayon, M., Meija, J., Malit, M. F., Wu, C. P., AbdelSamie, M., Chiang, C.-Y., Tagmount, A., deSouza, M., Neuhierl, B., Bock, A., Caruso, J., and Terry, N., 2004, Overexpression of selenocysteine methyltransferase in Arabidopsis and Indian mustard increaes Selenium tolerance and accumulation, Plant Physiol. 135 377-383. 

Pilon, M., Pwen, J. D., Garifullina, G. F., Kurihara, T., Mihara, H., Esaki, N., and Pilon-Smits, E. A. H., 2003, Enhanced selenium tolerance and accumulation in transgenic Arabidopsis expressing a mouse selenocysteine ya s. Plant Physiol. 131 1250-1257. 

The exclusion of selenium from the proteins of accumulator plants is thought to be the basis for their selenium tolerance. Their selenium metabolism is based mainly on water-soluble nonprotein forms such as selenium methylselenomethionine (Jacobs, 1989). The garlic odor characteristic of selenium-accumulator plants reflects the volatile organic compounds dimethylselenide and dime-thyldiselenide. Plants can suffer selenium toxicity as a result of selenium competition with essential metabolites for biochemical sites, replacement of essential ions by selenium, mainly major cations, selenate occupation of the sites of essential groups such as phosphate and nitrate, or selenium substimtion in essential sulfur compounds. 

Bender J, Gould JP, Vatcharapijam Y, et al. 1991. Uptake, transformation and fixation of selenium (VI) by a mixed selenium-tolerant ecosystem. Water Air Soil Pollut 59(3-4) 359-368. 

Microbiol Mol Biol Rev 79 61-80. doi 10.1128/MMBR.00037-14 Neuhierl B, Bock A (1996) On the mechanism of selenium tolerance in selenium-accumulating plants purification and characterization of a specific selenocysteine methyltransferase from cultured cells of Astragalus bisulcatus. Eur 1 Biochem 239 235-238... 

Van Hoewyk D, Garifullina GF, Ackley AR, Abdel-Ghany SE, Marcus MA, Fakra S, Ishiyama K, Inoue E, Pilon M, Takahashi H et al (2005) Overexpression of AtCpNifS enhances selenium tolerance and accumulation in Arabidopsis. Plant Physiol 139 1518-1528 Van Hoewyk D, Takahashi H, Inoue E, Hess ATM, Pilon-Smits EAH (2008) Transcriptome analyses give insights into selenium-stress responses and selenium tolerance mechanisms in Arabidopsis. Physiol Plant 132 236-253... 

WangeUne AL, Valdez JR, Lindblom SD, Bowling KL, Reeves FB, Pilon-Smits EAH (2011) Selenium tolerance in rhizosphere fungi from Se hyperaccumulator and non-hyperaccumulator plants. Am J Bot 98 1139-1147... 

These are known as chemically pure (CP) cadmiums. With the development of other uses for cadmium and selenium, costs have risen substantially in recent years. Some cost reduction may be obtained by use of the cadmium Hthopones. These have the same relative shades but have been coprecipitated onto about 60% barium sulfate. The resulting extensions give better money value, if the higher pigment loading can be tolerated, with no loss in properties. 

The wide substrate tolerance of lipases is demonstrated by the resolution of organometallic substrates [129-131]. The presence of tin, selenium, or tellurium in the structure of secondary alcohols does not inhibit the lipase activity and enantiopure organometallic alcohols were obtained by acylation in organic media (Figure 6.48). 

Extensive structural, optical, and electronic studies on the chalcopyrite semiconductors have been stimulated by the promising photovoltaic and photoelectrochem-ical properties of the copper-indium diselenide, CuInSe2, having a direct gap of about 1.0 eV, viz. close to optimal for terrestrial photovoltaics, and a high absorption coefficient which exceeds 10 cm . The physical properties of this and the other compounds of the family can be modulated to some extent by a slight deviation from stoichiometry. Thus, both anion and cation deficiencies may be tolerated, inducing, respectively, n- and p-type conductivities a p-type behavior would associate to either selenium excess or copper deficiency. 

One of the first considerations in the use of any chemical is possible accumulations of harmful residues in soils. Evidence proves beyond any doubt that many of the newer compounds remain in the soil for at least 5 years. How much longer they may persist, time alone can determine. We know that both selenium and molybdenum can be picked up from soils by plants, which thus become extremely toxic to animals, even when plants themselves are apparently unharmed. Often a given piece of land may be treated safely as far as one crop is concerned but another crop may be injured. For example, potatoes will tolerate large amounts of DDT in the soil as a means of controlling wireworms which are extremely destructive melons, on the other hand, are severely injured by excessive DDT in the soil. There can be no assurance in many cases as to the ultimate use of any... 

May, T.W. and G.L. McKinney. 1981. Cadmium, lead, mercury, arsenic, and selenium concentrations in freshwater fish, 1976-77 — National Pesticide Monitoring Program. Pestic. Monitor. Jour. 15 14-38. McDonald, L.J. 1986. Suspected lead poisoning in an Amazon parrot. Canad. Vet. Jour. 27 131-134. McLean, R.O. and A.K. Jones. 1975. Studies of tolerance to heavy metals in the flora of the rivers Ystwyth and Clarach, Wales. Freshwater Biol. 5 431 -444. 

Duncan, D.A. and J.F. Klaverkamp. 1983. Tolerance and resistance to cadmium in white suckers (Catostomus commersoni) previously exposed to cadmium, mercury, zinc, or selenium. Canad. Jour. Fish. Aquat. Sci. 40 128-138. 

Arsenic recoveries from the zinc column in the range 0.1-5pg ml-1 arsenic exceeded 97%. The concentrations at which certain elements interfere are shown in Table 12.16. Various other elements [A1 m, B m, Ca II, Cd II, Co II, Cr VI, Fe III, K I, Li I, Mg II, Mn H, Na I, Ni II, Pb II, S VI, Sn II and Zn II] showed no significant interference at the 500pg level. Only low senium concentrations in extracts can be tolerated. However, few environmental samples contain appreciable amounts of selenium. As selenium is not reduced to hydrogen selenide on the column, selenium will not interfere in the final determination step, but probably suppresses either arsenic reduction or arsine formation. Selenium appears to suppress arsine generation at high arsenic concentrations but causes a slight enhancement at low arsenic concentrations (around O.lpg), which could not be traced to arsenic impurities in the selenium standard used. 

Commercial selenium disulfide SeSj has been found to be very untoxic (for mice LD 50 per os 3.7 g/kg). Thus the material is 100 times less toxic than selenites. Daily oral administration of 5, 25, or 125 mg/kg of SeS2 for seven and a half weeks was tolerated by mice without signs of intoxication. As SeSj is used as a constituent of shampoos several investigations on the effects of the sulfide on the eyes, skin, and hair have been published chemotherapeutic activity... 

A metal cylinder is mounted to rotate about a horizontal axis. This is called the drum. The end-to-end dimension is the width of print to be produced plus a generous tolerance. The drum in the copiers originally developed by Xerox Corporation was manufactured with a surface coating of amorphous selenium (more recently, ceramic or organic... 

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