Performance of BL-8 dispersive and BL-9 scanning EXAFS beamlines at Indus-2 synchrotron

Gaur, Abhijeet; Dar, Davood Ah; Shrivastava, B. D.; Jha, S. N.; Bhattacharyya, D.

doi:10.1007/s12648-014-0610-7

Cited by 10 publications

(3 citation statements)

References 29 publications

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“…Uranium L III edge XAS measurements were carried out in fluorescence mode at the Scanning EXAFS beamline (BL-9) of INDUS-2 synchrotron source (2.5 GeV, 100 mA) at the Raja Ramanna Centre for Advanced Technology (RRCAT), Indore, India (77). The beamline uses a double crystal monochromator (DCM) which works in the photon energy range of 4 to 25 keV with a resolution of 10 4 at 10 keV.…”

Section: Methodsmentioning

confidence: 99%

Unusual Versatility of the Filamentous, Diazotrophic Cyanobacterium Anabaena torulosa Revealed for Its Survival during Prolonged Uranium Exposure

Acharya

Chandwadkar

Nayak

2017

Appl Environ Microbiol

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Reports on interactions between cyanobacteria and uranyl carbonate are rare. Here, we present an interesting succession of the metabolic responses employed by a marine, filamentous, diazotrophic cyanobacterium, Anabaena torulosa for its survival following prolonged exposure to uranyl carbonate extending up to 384 h at pH 7.8 under phosphate-limited conditions. The cells sequestered uranium (U) within polyphosphates on initial exposure to 100 M uranyl carbonate for 24 to 28 h. Further incubation until 120 h resulted in (i) significant degradation of cellular polyphosphates causing extensive chlorosis and cell lysis, (ii) akinete differentiation followed by (iii) extracellular uranyl precipitation. X-ray diffraction (XRD) analysis, fluorescence spectroscopy, X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) spectroscopy established the identity of the bioprecipitated uranium as a U(VI) autunite-type mineral, which settled at the bottom of the vessel. Surprisingly, A. torulosa cells resurfaced as small green flakes typical of actively growing colonies on top of the test solutions within 192 to 240 h of U exposure. A consolidated investigation using kinetics, microscopy, and physiological and biochemical analyses suggested a role of inducible alkaline phosphatase activity of cell aggregates/akinetes in facilitating the germination of akinetes leading to substantial regeneration of A. torulosa by 384 h of uranyl incubation. The biomineralized uranium appeared to be stable following cell regeneration. Altogether, our results reveal novel insights into the survival mechanism adopted by A. torulosa to resist sustained uranium toxicity under phosphate-limited oxic conditions. IMPORTANCE Long-term effects of uranyl exposure in cyanobacteria under oxic phosphate-limited conditions have been inadequately explored. We conducted a comprehensive examination of the metabolic responses displayed by a marine cyanobacterium, Anabaena torulosa, to cope with prolonged exposure to uranyl carbonate at pH 7.8 under phosphate limitation. Our results highlight distinct adaptive mechanisms harbored by this cyanobacterium that enabled its natural regeneration following extensive cell lysis and uranium biomineralization under sustained uranium exposure. Such complex interactions between environmental microbes such as Anabaena torulosa and uranium over a broader time range advance our understanding on the impact of microbial processes on uranium biogeochemistry.KEYWORDS biomineralization, cyanobacteria, phosphatase, polyphosphates, regeneration, uranium M icroorganisms have existed on earth for at least 3.5 billion years (1) and are the most successful life forms to date (2). They have been exposed to their immediate environments comprising essential elements or complex mixtures of naturally occur-

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Section: Methodsmentioning

confidence: 99%

Unusual Versatility of the Filamentous, Diazotrophic Cyanobacterium Anabaena torulosa Revealed for Its Survival during Prolonged Uranium Exposure

Acharya

Chandwadkar

Nayak

2017

Appl Environ Microbiol

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“…The Cu K-edge x-ray absorption spectra of the copper complexes have been recorded on BL-9 scanning type EXAFS beamline at 2.5 GeV Indus-2 synchrotron source at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore, India. 20 The main constituent of this beamline is a Double Crystal Monochromator (DCM) which selects x-rays of a particular energy from the beam of continuous x-rays, that is, white radiation, emitted from the synchrotron storage ring. The DCM has two Si (111) crystals carved out in a single block.…”

Section: Experimental and Data Analysismentioning

confidence: 99%

Investigating local coordination and electronic nature of Cu centers in the copper complexes having aspartic and glutamic acids

Hinge,

Bairagi,

Yadav

et al. 2023

X-Ray Spectrometry

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X‐ray absorption fine structure (XAFS) at the Cu K‐edge in copper complexes of L‐aspartic acid (asp) and L‐glutamic acid (glu), namely, [Cu(L‐asp)(H2O)].H2O (1) and [Cu(L‐glu)(H2O)].H2O (2) have been investigated using synchrotron radiation. Though, the crystal structure of both of the complexes 1 and 2 have been studied earlier using x‐ray crystallography, it was considered worthwhile to study the coordination geometry and electronic nature of Cu metal center using XAFS. EXAFS analysis indicated that Cu has distorted tetragonal pyramidal and distorted octahedral coordination in complexes, respectively. The XANES spectra have been simulated for the Cu center in the complexes and compared with the experimental XANES spectra. Further, p‐DOS and d‐DOS calculated simultaneously for absorbing Cu metal center have been correlated with the features and shape of the simulated XANES spectra as well as the experimental spectra.

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“…The EXAFS measurements were carried out at the energy dispersive EXAFS beam line (BL-8) and energy scanning EXAFS beam line (BL-9) of the Indus-2 synchrotron source at the Raja Ramanna Centre for Advanced Technology (RRCAT), Indore, India. 23,24 The U and Bi L 3 edges were probed using transmission geometry at BL-8, while the La L 3 edge was probed using fluorescence geometry at BL-9. The energy dispersive EXAFS beam line (BL-8) uses a Si(111)-based bent crystal polychromator and a position-sensitive CCD detector.…”

Section: Exafs Measurementsmentioning

confidence: 99%

Investigations on local structures in new Bi_2−2xLa_2xUO₆ (x = 0–0.05) solid solutions: a combined XRD, EXAFS, PL and EPR study

et al. 2016

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La doped Bi2UO6 solid solutions of the general formula Bi2-2xLa2xUO6 (x = 0-0.05) were prepared by the solid state reaction of Bi2O3, La(OH)3 and U3O8 in a stoichiometric ratio. These solid solutions were characterized by X-ray diffraction, Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Spectroscopy (XANES) studies. It was found that La goes to the Bi sites of the Bi2UO6 lattice during the formation of these solid solutions. For further confirmation, a photoluminescence (PL) study on an iso-structural Bi1.96Eu0.04UO6 was performed, and this supports the above observation. The solid solutions were also probed by EPR studies. The PL and EPR studies suggest that there are doping induced oxygen vacancies in these solid solutions.

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Performance of BL-8 dispersive and BL-9 scanning EXAFS beamlines at Indus-2 synchrotron

Cited by 10 publications

References 29 publications

Unusual Versatility of the Filamentous, Diazotrophic Cyanobacterium Anabaena torulosa Revealed for Its Survival during Prolonged Uranium Exposure

Unusual Versatility of the Filamentous, Diazotrophic Cyanobacterium Anabaena torulosa Revealed for Its Survival during Prolonged Uranium Exposure

Investigating local coordination and electronic nature of Cu centers in the copper complexes having aspartic and glutamic acids

Investigations on local structures in new Bi_2−2xLa_2xUO₆ (x = 0–0.05) solid solutions: a combined XRD, EXAFS, PL and EPR study

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Performance of BL-8 dispersive and BL-9 scanning EXAFS beamlines at Indus-2 synchrotron

Cited by 10 publications

References 29 publications

Unusual Versatility of the Filamentous, Diazotrophic Cyanobacterium Anabaena torulosa Revealed for Its Survival during Prolonged Uranium Exposure

Unusual Versatility of the Filamentous, Diazotrophic Cyanobacterium Anabaena torulosa Revealed for Its Survival during Prolonged Uranium Exposure

Investigating local coordination and electronic nature of Cu centers in the copper complexes having aspartic and glutamic acids

Investigations on local structures in new Bi2−2xLa2xUO6 (x = 0–0.05) solid solutions: a combined XRD, EXAFS, PL and EPR study

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Investigations on local structures in new Bi_2−2xLa_2xUO₆ (x = 0–0.05) solid solutions: a combined XRD, EXAFS, PL and EPR study