title: Epithermal neutron activation analysis of Cr(VI)-reducer basalt-inhabiting bacteria.
abstract: Epithermal neutron activation analysis (ENAA) has been applied to study elemental composition of Cr(VI)-reducer bacteria isolated from polluted basalts from the Republic of Georgia. Cr(VI)-reducing ability of the bacteria was examined by electron spin resonance, demonstrating that the bacteria differ in their rates of Cr(VI) reduction. A well-pronounced correlation between the ability of the bacteria to accumulate Cr(V) and their ability to reduce Cr(V) to Cr(III) observed in our experiments is discussed. Elemental analysis of these bacteria also revealed that basalt-inhabiting bacteria are distinguished by relative contents of essential elements such as K, Na, Mg, Fe, Mn, Zn, and Co. A high rate of Cr(III) formation correlates with a high concentration of Co in the bacterium. ENAA detected some similarity in the elemental composition of the bacteria. The relatively high contents of Fe detected in the bacteria (140-340 microg/g of dry weight) indicate bacterial adaptation to the environmental conditions typical of the basalts. The concentrations of at least 12-19 different elements were determined in each type of bacteria simultaneously starting with the major to ultratrace elements. The range of concentrations spans over 8 orders of magnitude.
authors.affiliation: Joint Institute for Nuclear Research, Dubna, Moscow Region, Russian Federation, Andronikashvili Institute of Physics and Chavchavadze State University, Tbilisi, Georgia.
authors.forename: Nelly Yasonovna
authors.initials: NY
authors.lastname: Tsibakhashvili
authors.forename: Marina Vladimirovna
authors.initials: MV
authors.lastname: Frontasyeva
authors.forename: Elena Ivanovna
authors.initials: EI
authors.lastname: Kirkesali
authors.forename: Nadezhda Gennadievna
authors.initials: NG
authors.lastname: Aksenova
authors.forename: Tamaz Levanovich
authors.initials: TL
authors.lastname: Kalabegishvili
authors.forename: Ivana Georgievich
authors.initials: IG
authors.lastname: Murusidze
authors.forename: Ligury Mikhailovich
authors.initials: LM
authors.lastname: Mosulishvili
authors.forename: Hoi-Ying N
authors.initials: HY
authors.lastname: Holman
mesh_terms: D001173:Arthrobacter / Q000737:chemistry* / Q000378:metabolism; D002857:Chromium / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D005846:Georgia (Republic); D008903:Minerals; D009501:Neutron Activation Analysis / Q000379:methods*; D010084:Oxidation-Reduction; D017640:Silicates; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008903:Minerals; D017640:Silicates; D012989:Soil Pollutants; C060346:basalt; D002857:Chromium