Arsenic fungi

The best protection for wood against the attack of decay fungi, insects, or marine borers is obtained by applying preservatives under pressure before installation (61,62). Both oil-type preservatives, such as creosote or petroleum solutions of pentachlorophenol, and waterborne preservatives, such as copper-chrome arsenate and ammoniacal-copper arsenate, are used when wood is to be in direct contact with the ground or in the marine environments. 

Systemic mycoses are caused either by true pathogenic fungi (endemic in distinct areas of USA/South America) or by opportunistic fungi that induce severe infections in immunosuppressed patients. The arsenal for the treatment of deep organ mycoses is relatively small Amph B, 5FC, azoles (FLU, ITRA, voriconazole (NBA filing)) and CAS. 

Some metals, arsenic and mercury for example, may be volatilized by methylation due to activity of anaerobic microorganisms. Arsenic can be methylated by methanogenic Archaea and fungi to volatile toxic dimethylarsine and trimethylarsine or can be converted to less toxic nonvolatile methanearsonic and dimethylarsinic acids by algae [42]. 

Bacterial methylation of arsenate by a methanogen was first reported by McBride and Wolfe (135) in 1971, and reports of nonmethanogenic bacterial methylation followed. These transformations are now known to be effected by a range of bacteria, and the mechanisms are likely to be similar to those proposed for fungi (32). 

The methylation of arsenic is entirely or almost entirely biotic (Frankenberger and Arshad, 2002), 367. Specifically, certain fungi (including yeasts) and bacteria are capable of methylating arsenic ((Bentley and Chasteen, 2002), 257-260 (Cullen and Reimer, 1989), 717-724 Chapter 4). Only limited evidence exists for the chemical (abiotic) methylation of arsenic. As mentioned earlier, some volatile arsines have been produced in the laboratory from photochemical reactions involving As(III), carboxylic acids, and ultraviolet radiation (Guo et al., 2005 McSheehy et al., 2005). 

Globally, volcanoes release about 17 150 metric tons (t) of arsenic per year into the atmosphere (It equals 1000 kg (Matschullat, 2000), 300). Other significant natural sources of gaseous arsenic emissions include geothermal vents, wind erosion of soils and sediments, forest and coal seam fires, and sea spray ((Cullen and Reimer, 1989), 740 (Nriagu, 1989) Chapter 3). Under reducing conditions in soils, fungi and... 

Perhaps as much as 26 200 t of arsenic may annually volatilize into the atmosphere from soils (Matschullat, 2000), 300-301. Much of this volatilization is due to microbial activity (Frankenberger and Arshad, 2002), 363-364. Under reducing conditions in soils, fungi and other microorganisms may produce gaseous arsine and methylated arsines, such as methylarsine, dimethylarsine and trimethylarsine ((Mandal and Suzuki, 2002), 205 (Lrankenberger and Arshad, 2002), 363 (Oremland and Stolz, 2003), 939 Chapter 4). 

Like water, arsenic in contaminated soils, sediments, and even solid wastes may be treated with plants, fungi, bacteria, or other biological organisms. The applications, limitations, and advantages of biological treatment methods with solid materials are often similar to those with water. To be exact, many bioremediation methods are designed to simultaneously treat contaminants in soils, sediments, and water (e.g. phytoremediation). 

Kartal et al. (2004) also investigated the use of fungi to remove arsenic from CCA-treated wood. Three brown-rot fungi (Fomitopsis palustris, Coniophora puteana, and Laetiporus sulphureus) were initially... 

There were 37 distinct enzymes that contain molybdenum or tungsten known by the end of 1997. The enzymes are diverse in function, broadly distributed, and include oxidases, reductases, dehydrogenases, a transhydroxylase, and a hydratase. The Mo enzymes are found in eubacteria, archae, protista, fungi, plants, and animals (including humans) and are essential for respiration and carbon and nitrogen assimilation. Several of the enzymatic substrates and products are key components in the nitrogen, sulfur, selenium, carbon, and arsenic cycles and have major biological and environmental impact. 

Svlejkovec, Z., Byrne, A.R., Stijve, T., Goessler, W. and Irgolic, K.G. (1997) Arsenic compounds in higher fungi. Appl. Organomet. Chem., 11, 673-682. 

Liver tumors have been directly attributed to exposure to some toxicants. Androgens (associated with male sex hormones), aflatoxins (from fungi, see Chapter 19), arsenic, and thorium dioxide (administered as a suspension to many patients between 1920 and 1950 as a radioactive contrast agent for diagnostic purposes) are known to cause liver cancer. 

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