Frontiers in Microbiology (Jul 2016)

Probing Synechocystis-arsenic interactions through extracellular nanowires

  • Sandeep Sure,
  • M Leigh Ackland,
  • Aditya Gaur,
  • Priyanka Gupta,
  • Alok Adholeya,
  • Mandira Kochar

DOI
https://doi.org/10.3389/fmicb.2016.01134
Journal volume & issue
Vol. 7

Abstract

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Microbial nanowires (MNWs) can play an important role in the transformation and mobility of toxic metals/metalloids in environment. The potential role of MNWs in cell-arsenic (As) interactions has not been reported in microorganisms and thus we explored this interaction using Synechocystis PCC 6803 as a model system. The effect of half maximal inhibitory concentration (IC50) [~300mM As (V) and ~4mM As (III)] and non-inhibitory [4X lower than IC50 i.e. 75mM As (V) and 1mM As (III)] of As was studied on Synechocystis cells in relation to its effect on Chlorophyll (Chl) a, type IV pili (TFP)-As interaction and intracellular/extracellular presence of As. In-silico analysis showed that subunit PilA1 of electrically conductive TFP i.e. microbial nanowires of Synechocystis have putative binding sites for As. In agreement with in-silico analysis, transmission electron microscopy analysis showed that As was deposited on Synechocystis nanowires at all tested concentrations. The potential of Synechocystis nanowires to immobilize As can be further enhanced and evaluated on a large scale and thus can be applied for bioremediation studies.

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