Thauera selenatis

DeMoll-Decker H, JM Macy (1993) The periplasmic nitrite reductase of Thauera selenatis may catalyze the reduction of selenite to elementary selenium. Arch Microbiol 160 241-247. 

Macy JM, S Rech, G Auling, M Dorsch, E Stackebrandt, LI Sly (1993) Thauera selenatis gen. nov., sp. nov., a member of the beta subclass of Proteobacteria with a novel type of anaerobic respiration. Int J Syst Bacteriol 43 135-142. 

Schroder I, S Rech, T Krafft, JM Macey (1997) Purification and characterization of the selenate reductase from Thauera selenatis. J Biol Chem 272 23765-23768. 

The selenate reductase from Enterobacter cloacae SLDla-1 functions only under aerobic conditions, and is not able to serve as an electron acceptor for anaerobic growth, in contrast to the periplasmic enzyme from Thauera selenatis (Schroder et al. 1997). In E. cloacae there are separate nitrate and selenate reductases, both of which are membrane-bound. The selenate reductase is able to reduce chlorate and bromate though not nitrate, contains Mo, heme and nonheme iron, and consists of three subunits in an a3p3y3 configuration. 

The chlorate reductase has been characterized in strain GR-1 where it was found in the periplasm, is oxygen-sensitive, and contains molybdenum, and both [3Fe-4S] and [4Fe-4S] clusters (Kengen et al. 1999). The arsenate reductase from Chrysiogenes arsenatis contains Mo, Fe, and acid-labile S (Krafft and Macy 1998), and the reductase from Thauera selenatis that is specific for selenate, is located in the periplasmic space, and contains Mo, Fe, acid-labile S, and cytochrome b (Schroeder et al. 1997). In contrast, the membrane-bound selenate reductase from Enterobacter cloacae SLDla-1 that cannot function as an electron acceptor under anaerobic conditions contains Mo and Fe and is distinct from nitrate reductase (Ridley et al. 2006). 

Macy, J. M., Lawson, S., and DeMoll-Decker, H., Bioremediation of Selenium Oxyanions in San Joaquin Drainage Water Using Thauera selenatis in a Biological Reactor System, Appl. Microbiol. Biotechnol., 40 588 (1993)... 

Obviously the redox poise in biological systems is very important and the movement of selenium through this process has been investigated for denitrifiers such as Paracoccus denitrificans,159 a specialized selenate-respiring bacterium Thauera selenatis which used selenate as the sole electron acceptor,160,161 and phototrophic bacteria which produced different reduced forms of selenium when amended with either selenite or selenate and even added insoluble elemental Se.162 As noted above, Andreesen has commented on the importance of redox active selenocysteines135 and Jacob et al.136 note the importance of the thioredoxin system to redox poise. 

Rech SA, Macy JM. 1992. The terminal reductases for selenate and nitrate respiration in Thauera selenatis are two distinct enzymes. J Bacteriol 174 7316-20. 

Macy JM, Lawson S. 1993. Cell yield [Y(M)] of Thauera selenatis grown anaerobically with acetate plus selenate or nitrate. Arch Microbiol 160 295-8. 

Experimental practice and selected results. Phys Rev 11 4825-4835 Lytle FW, Sayers DE, Stem EA (1982) The history and modem practice of EXAFS spectroscopy. In Bonnelle C, Mande (eds) Advances in X-ray Spectroscopy. Pergamon Press, New York, p 267-286 Lytle FW, Via GH, Sinfelt JH (1980) X-ray absorption spectroscopy catalyst applications. In Winick H, Doniach S (eds) Synchrotron Radiation Research. Plenum Press, New York, p 401-424 MacDowell AA, Celestre RS, Tamura N, Spolenak R, Valek BC, Brown WL, Bravman JC, Padmore HA, BattermanBW, Patel (2001) Submicron X-ray diffraction. Nucl Instrum Methods A 468 936-943 Macy JM (1994) Biochemistry of selenium metabolism by Thauera selenatis gen. nov. sp. nov. and use of the organism for bioremediation of selenium oxyanions in San Joaquin Valley drainage water. In Frankenberger WT Jr, Benson S (eds) Selenium in the Environment. Marcel Decker, Inc., New York, p 421-444... 

Her most recent scientific contributions were in the areas of bacterial selenium and arsenic metabolism. Her interest in bioremediation began with selenium-contaminated water found in the San Joaquin Valley in California, from which she isolated the first bacterium able to respire with selenate (reducing it to selenite and then to elemental selenium) using acetate as the electron donor/ carbon source. This organism was found to represent a new genus and named Thauera selenatis. She studied the organism extensively for the purpose of selenium bioremediation. This involved the design and implementation of lab-scale and then pilot-scale reactors. 

---