Can E.coli combat ionizing radiation?

-Anuska Sen,Team bioXone

Ionizing radiation (IR) is known to have numerous ill-effects and can even be fatal to most organisms on exposure at high concentrations. Scientists are continuously in search of organisms or strains of bacteria that are resistant to such radiation, meaning which possess the property of “radio-resistance”.

Till date, it was known that the polyextremophile Deinococcus radiodurans was the most radio-resistant organism, and hence The Guinness Book Of World Records mentions it as the world’s toughest known bacterium. However, on conducting extensive research on the bacterium Escherechia coli (E.coli), researcher Cox and the team have developed a specific strain of E.coli (known as IR10-100) which shows similar radio-resistance level as Deinococcus radiodurans. Further, the IR10-100 variety showed better protection of intracellular proteins from being hydroxylated due to the ionizing radiation. The study has also reported that three other strains of E.coli, namely IR9-100, IR11-100and IR12-100 were developed, 99% of whose population could show tolerance to radiation of up to 3000 Gy (or 300000 rad) intensity.

Earlier it was thought that radio-resistance was caused as a result of changes in the DNA repair mechanisms of these organisms, but this present study has brought up some other underlying mechanisms too. Various factors such as biogenesis of an important co-factor, iron-sulphur cluster via the sulphur utilization factor D (SufD) mechanism; production of a foul-smelling diamine called Cadaverine (CadA), and the presence of various ATP-synthesizing proteins might be some of those mechanisms responsible for IR(radio) resistance. These strains of E.coli can protect themselves from the Reactive Oxygen Species (ROS) molecules and thus remain unaffected by the ionizing radiation.

Employing such an approach, IR-resistant bacteria can be engineered so that in the future these can be potential tools to reduce or wipe out harmful radioactive materials in the environment.

This article has been published in frontiers in Microbiology

Source: Bruckbauer S.T., Martin J., Minkoff B.B., Veling M.T., Lancaster I., Liu J., Trimarco J.D.,Bushnell B., Lipzen A., Wood E.A., Sussman M.R., Pennacchio C., Cox M.M.; (2020); Physiology of Highly Radioresistant Escherichia coli After Experimental Evolution for 100 Cycles of Selection; frontiers in Microbiology; 11:2297.

https://doi.org/10.3389/fmicb.2020.582590

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