Probing Synechocystis-Arsenic Interactions through Extracellular Nanowires

Area of Science:

• Environmental microbiology
• Biogeochemistry
• Nanotechnology

Background:

• Microbial nanowires (MNWs) are crucial in environmental metal transformation and mobility.
• The interaction between MNWs and arsenic (As) in microorganisms remains largely unexplored.
• Synechocystis PCC 6803 serves as a model organism to investigate these interactions.

Purpose of the Study:

• To investigate the role of microbial nanowires in cell-arsenic interactions using Synechocystis PCC 6803.
• To analyze the effect of different arsenic concentrations on Synechocystis cells, chlorophyll a, and type IV pili (TFP)-arsenic interactions.
• To determine the intracellular and extracellular distribution of arsenic in relation to MNWs.

Main Methods:

• In silico analysis of the PilA1 subunit of TFP for putative arsenic binding sites.
• Transmission electron microscopy (TEM) to visualize arsenic deposition on Synechocystis nanowires.
• Exposure of Synechocystis cells to inhibitory and non-inhibitory concentrations of As (V) and As (III).

Main Results:

• In silico analysis revealed putative arsenic binding sites on the PilA1 subunit of Synechocystis TFP (MNWs).
• Transmission electron microscopy confirmed arsenic deposition on Synechocystis nanowires across all tested concentrations.
• Arsenic interaction with Synechocystis cells affected chlorophyll a and TFP-arsenic binding.

Conclusions:

• Synechocystis microbial nanowires exhibit a direct interaction with arsenic, binding it extracellularly.
• The findings highlight the potential of Synechocystis MNWs for immobilizing arsenic.
• Further research and large-scale evaluation are warranted for developing bioremediation strategies using these nanowires.