Showing posts with label V. M. Popik. Show all posts
Showing posts with label V. M. Popik. Show all posts

Tuesday, January 9, 2018

Abstract-Stress-induced systems in Escherichia coli and their response to terahertz radiation


S. E. Peltek, E. V. Demidova, V. M. Popik, T. N. Goryachkovskaya

https://link.springer.com/article/10.1134/S2079059717080019

We summarize the latest data concerning the reactions of Escherichia coli to nonthermal terahertz radiation. Escherichia coli is the simplest and most convenient model object for studying the effects of terahertz radiation on living organisms. Its genetics and metabolism have been well studied, and its easy accessibity to genetic engineering allows designing biosensors that employ the promoters of genes activated by certain stress factors and the reporter GFP protein. Escherichia coli cells transformed with such biosensor constructs produce easily quantitatable fluorescence in response to terahertz radiation. In this review, we present data on the reaction of certain E. сoli stress-induced systems to terahertz radiation, both ours and reported by other authors. We discuss experimental results for E. сoli/pKatGGFP, E. сoli/pCopAGFP, and E. сoli/pEmrRGFP biosensors, which are used to identify E. сoli genetic networks responding to oxidative stress, copper ion homeostasis failures, and antiseptics, respectively. The data reviewed indicate that exposure to nonthermal terahertz radiation activates E. сoli gene networks related to oxidative stress and copper ion homeostasis but does not affect those induced by antibiotics, protonophores, or superoxide anions. The fact that E. сoli/pKatGGFP and E. сoli/pCopAGFP biosensors have different activation and reaction periods when exposed to terahertz radiation and natural inducers suggests that the responses of oxidative stress and copper ion homeostasis systems to terahertz radiation are specific.

Wednesday, January 14, 2015

Abstract-No DNA damage response and negligible genome-wide transcriptional changes in human embryonic stem cells exposed to terahertz radiation


http://www.nature.com/srep/2015/150113/srep07749/full/srep07749.html

Terahertz (THz) radiation was proposed recently for use in various applications, including medical imaging and security scanners. However, there are concerns regarding the possible biological effects of non-ionising electromagnetic radiation in the THz range on cells. Human embryonic stem cells (hESCs) are extremely sensitive to environmental stimuli, and we therefore utilised this cell model to investigate the non-thermal effects of THz irradiation. We studied DNA damage and transcriptome responses in hESCs exposed to narrow-band THz radiation (2.3 THz) under strict temperature control. The transcription of approximately 1% of genes was subtly increased following THz irradiation. Functional annotation enrichment analysis of differentially expressed genes revealed 15 functional classes, which were mostly related to mitochondria. Terahertz irradiation did not induce the formation of γH2AX foci or structural chromosomal aberrations in hESCs. We did not observe any effect on the mitotic index or morphology of the hESCs following THz exposure.