Adaptations of Escherichia coli K 12 to Synchrotron Sourced THz Radiation

Elena P Ivanova; The Hong Phong Nguyen; Denver P Linklater; Phuc H Le; Zoltan Vilagosh; Palalle G Tharushi Perera; Dominique R T Appadoo; Jitraporn Vongsvivut; Tanavi Sharma; Michael G Leeming; Nicholas A Williamson; Eric Hanssen; Chaitali Dekiwadia; Mark J Tobin; Saulius Juodkazis; Rodney J Croft

doi:10.1021/acsomega.4c08710

Adaptations of Escherichia coli K 12 to Synchrotron Sourced THz Radiation

ACS Omega. 2024 Dec 5;9(50):49878-49886. doi: 10.1021/acsomega.4c08710. eCollection 2024 Dec 17.

Authors

Elena P Ivanova¹, The Hong Phong Nguyen¹, Denver P Linklater², Phuc H Le^{1

3}, Zoltan Vilagosh¹, Palalle G Tharushi Perera¹, Dominique R T Appadoo⁴, Jitraporn Vongsvivut⁴, Tanavi Sharma⁵, Michael G Leeming⁵, Nicholas A Williamson⁵, Eric Hanssen³, Chaitali Dekiwadia⁶, Mark J Tobin⁴, Saulius Juodkazis⁷, Rodney J Croft⁸

Affiliations

¹ STEM College, School of Science, RMIT University, Melbourne, Victoria 3000, Australia.
² Biomedical Engineering, Graeme Clark Institute, The University of Melbourne, Parkville, Victoria 3010, Australia.
³ Ian Holmes Imaging Centre, ARC Centre for Cryo Electron Microscopy of Membrane Protein and Department of Biochemistry and Pharmacology, Bio21 Institute, University of Melbourne, Parkville, Victoria 3052, Australia.
⁴ THz/Far-IR Beamline, ANSTO-Australian Synchrotron, Clayton, Victoria 3168, Australia.
⁵ Melbourne Mass Spectrometry and Proteomics Facility, Bio 21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010 Australia.
⁶ RMIT Microscopy and Microanalysis Facility, College of Science, Engineering and Health, RMIT University, P.O. Box 2476, Melbourne, Victoria 3001, Australia.
⁷ Centre for Quantum and Optical Sciences, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
⁸ School of Psychology, University of Wollongong, Wollongong, New South Wales 2522, Australia.

Abstract

The biological effects of electromagnetic field (EMF) irradiation in the terahertz (THz) range remain ambiguous, despite numerous studies that have been conducted. In this paper, the metabolic response of Escherichia coli K 12 to EMF irradiation was examined using a 1.0 W m^-2 incident synchrotron source (SS) in the range of 0.5-18.0 THz for over 90 min of continuous exposure at 25 °C. This continuous SS THz exposure induced periodic decreases in the cell growth after 10, 20, and 40 min of exposure compared to a time-matched control; however, the number of viable cells thereafter grew. The physiological status of treated cells immediately after exposure was assessed by using the direct plate counting technique and electron microscopy. Analysis of scanning electron microscopy (SEM) and high-resolution cryogenic transmission electron (cryo-TEM) micrographs showed that approximately 20% of the SS THz-exposed E. coli cells exhibited a deformed outer membrane, membrane perturbations, and leakage of cytosol. The proteome changes in E. coli cells after 18 h postexposure were associated with cellular response to plasma membrane regulation including phospholipid biosynthetic process and osmotic stress. The results of this study highlighted that E. coli cells can promptly activate the fundamental mechanisms in response to prolonged exposure to THz radiation that are evolutionarily developed to withstand other environmental stressors.