Arsenate respiratory

Perez-Jimenez, J.R., DeFraia, C., Young, L.Y. (2005). Arsenate respiratory reductase gene (arrA) for Desulfosporosinus sp. strain Y5. Biochem. Biophys. Res. Commun. 338 825-9. 

Desorption on Metal Reduction Many bacteria and archaea can respire on Mn(lll/tV) and Fe(lll) oxides, leading to their dissolution, with the potential for concomitant displacement of arsenic into the aqueous phase (Cummings et al., 1999). In fact, within most soils and sediments, total As levels correlate with Fe content rather than Al or clay content (Smedley and Kinniburgh, 2002), and thus reductive dissolution—transformation of Fe(lll) phases should have a major impact on arsenic. Respiratory reduction of Fe in sediments generally occurs in zones where O2, NOs , and Mn(lV) [all being oxidants of Fe(ll) and alternative electron acceptors] are diminished (Lovley, 2000). 

Mode of Action. The fundamental biochemical lesion produced by arsenicals is the result of reaction between As " and the sulfhydryl groups of key respiratory enzymes such as pymvate and a-ketoglutarate dehydrogenases. 

Lower respiratory Phosgene nitrogen dioxide arsenic trichloride. ... 

Carcinogens Cancer-producing agents Skin Respiratory Bladder/urinary tract Liver Nasal Bone marrow Coal tar pitch dust crude anthracene dust mineral oil mist arsenic. Asbestos polycyclic aromatic hydrocarbons nickel ore arsenic bis-(chloromethyl) ether mustard gas. p-naphthylamine benzidine 4-am i nodi pheny lam ine. Vinyl chloride monomer. Mustard gas nickel ore. Benzene. 

Krafft T, JM Macey (1998) Purification and characterization of the respiratory arsenate reductase of Chrysio-genes arsenatis. Eur J Biochem 255 647-653. 

Saltikov CW, DK Newman (2003) Genetic identification of a respiratory arsenate reductase. Proc Natl Acad Sci USA 100 10983-10988. 

Immediately dangerous to life or health (IDLH) levels are the ceiling limit for respirators other than SCBAs. However, IDLH levels have not been established for arsenical vesicants. Therefore, any potential exposure to these agents should be regarded with extreme caution and the use of SCBAs for respiratory protection should be considered. 

Exposure to arsenic has been associated with different types of human cancers such as respiratory cancers and epidermoid carcinomas of the skin, as well as precancerous dermal keratosis. The epidemiological evidence of human carcinogenicity is supported by carcinogenesis in experimental animals (Deknudt et al. 1986). 

The literature emphasizes that arsenic metabolism and toxicity vary greatly between species and that its effects are significantly altered by numerous physical, chemical, and biological modifiers. Adverse health effects, for example, may involve respiratory, gastrointestinal, cardiovascular, and hematopoietic systems, and may range from reversible effects to cancer and death, depending partly on the physical and chemical forms of arsenic tested, the route of administration, and the dose. 

Chrysiogenes arsenatis is the only known organism capable of using acetate as the electron donor and arsenate as the terminal electron acceptor for growth. This reduction of arsenate to arsenite is catalyzed by an inducible respiratory arsenate reductase, which has been isolated and characterized by Kraft and Macy (1998). Arsenate reductase (Arr) from C. arsenatis is a... 

The recently isolated Desulfotomaculum strain Ben-RB is able to grow using lactate as a substrate and arsenate as the sole electron acceptor (Macy et al. 2000). It has been proposed that arsenate reductase is associated with the respiratory chain of this organism, because >98% of the arsenate reductase bound to the plasma membrane. 

Excessive amounts of arsenic can cause skin, lung, and heart diseases, and gastrointestinal disorders, and it is known to have a carcinogenic influence. As" " compounds, which are bound by erythrocytes, affect the activity of numerous enzymes - especially those involved in respiratory processes (Cebrian et al., 1983 Done and Peart, 1971 National Academy of Sciences, 1977 WHO, 2001). 

Anaerobic metabolism occnrs nnder conditions in which the diffusion rate is insufficient to meet the microbial demand, and alternative electron acceptors are needed. The type of anaerobic microbial reaction controls the redox potential (Eh), the denitrification process, reduction of Mu and SO , and the transformation of selenium and arsenate. Keeney (1983) emphasized that denitrification is the most significant anaerobic reaction occurring in the subsurface. Denitrification may be defined as the process in which N-oxides serve as terminal electron acceptors for respiratory electron transport (Firestone 1982), because nitrification and NOj" reduction to produce gaseous N-oxides. hi this case, a reduced electron-donating substrate enhances the formation of more N-oxides through numerous elechocarriers. Anaerobic conditions also lead to the transformation of organic toxic compounds (e.g., DDT) in many cases, these transformations are more rapid than under aerobic conditions. 

Acute inhalation exposures have resulted in irritation of the upper respiratory tract, even leading to nasal perforations. Occupational exposure to arsenic compounds results in hyperpigmentation of the skin and hyperkeratoses of palmar and plantar surfaces, as well as dermatitis of both primary irritation and sensitization types. Impairment of peripheral circulation and Raynaud phenomenon have been reported with long-term exposure. ... 

Arsenic trichloride is a vesicant and can cause severe damage to the respiratory system on inhalation it is rapidly absorbed through the skin, and a fatal case after a spill on the skin has been reported. The vapor of arsenic trichloride is highly irritating to the eyes. Some organic arsenicals, such as arsanilates, have a selective effect on the optic nerve and can cause blindness. 

Lee-Eeldstein A Cumulative exposure to arsenic and its relationship to respiratory cancer among copper smelter employees, f Occup Med 28 296-302, 1986... 

Lung damage after chronic exposure to fumes in industry has not been described. The higher incidence of respiratory cancer reported in copper smelters is due to the presence of arsenic in the ore. ... 

Owens, E.J., Weimer, J.T., Ballard, T.A., Ford, D.F., Samuel, J.B., Hopcus, M.W., Merkey, R.P., and Olson, J.S. Ocular, cutaneous, respiratory and Intratracheal toxicity of solutions of CS and EA 3547 In glycol and glycol ether in animals. U.S. Army Medical Research Laboratory, Edgewood Arsenal, Md. 

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