Application of emission (57Co) Mössbauer spectroscopy in bioscience

Application of 57Co emission Mössbauer spectroscopy to studying biocomplexes in frozen solutions

“…The absorber (K 4 [ 57 Fe(CN) 6 ] 3H 2 O) was attached to a vibrator in the γ-ray beam path (sampleabsorber-detector). Other details of EMS measurements and statistical treatment of emission spectra were described elsewhere [7,12]. All isomer shift values are presented relative to α-Fe at ambient temperature (converted into a form compatible with that of conventional absorption 57 Fe Mössbauer measurements, positive with regard to α-Fe).…”

“…Note that the 57 Co→ 57 Fe nuclear transformation, proceeding via electron capture by the 57 Co nucleus (which thereby turns into 57 Fe) with a subsequent Auger cascade developing within 10 −14 to 10 −15 s, is followed by emission of a 14.4 keV γ-quantum (ca. 10 −7 s after the electron capture) [1,7,8]. Thus, the resulting substance under investigation using the EMS technique may be described as an 57 Fe complex substituted for the 'parent' 57 Co binding site (retaining its geometry).…”

“…The 57 Co EMS technique is several orders of magnitude more sensitive than its 57 Fe absorption counterpart [1] that, nevertheless, has been widely applied in biology and biomedicine (for recent reports and reviews see, e.g., [2][3][4][5][6]). As for EMS, the obvious methodological difficulties, arising due to using the radionuclide in the samples under study, restrain EMS applications in bioscience [7]. Cobalt has a broad range of physiological and biochemical functions; e.g., in many organisms it is involved in diverse enzymatic activities.…”

“…As the Mössbauer effect is observed in a solid matrix only, solutions or liquid samples are commonly studied rapidly frozen [1], so that the overall structure of the resulting frozen (glassy) matrix would adequately reflect that of the initial liquid. The appearance of after-effects of the 57 Co→ 57 Fe nuclear transformation, though complicating the EMS spectra, yet can provide additional information related to the electron acceptor properties of the 57 Co microenvironment [7,8].…”

Co2 + interaction with Azospirillum brasilense Sp7 cells: a 57Co emission Mössbauer spectroscopic study

“…Cobalt is a trace element with a wide variety of biological functions [1,2], which at higher concentrations can become toxic [3]. Interaction of bacterial cells with cobalt ions, besides its scientific aspects [2][3][4], is also of ecological significance [5].…”