Biologically Synthesized Gold Nanoparticles Ameliorate Cold and Heat Stress-Induced Oxidative Stress in Escherichia coli.
Due to their unique physical, chemical, and optical properties, gold nanoparticles (AuNPs) have recently attracted much interest in the field of nanomedicine, especially in the areas of cancer diagnosis and photothermal therapy. Because of the enormous potential of these nanoparticles, various physical, chemical, and biological methods have been adopted for their synthesis. Synthetic antioxidants are dangerous to human health. Thus, the search for effective, nontoxic natural compounds with effective antioxidative properties is essential. Although AuNPs have been studied for use in various biological applications, exploration of AuNPs as antioxidants capable of inhibiting oxidative stress induced by heat and cold stress is still warranted. Therefore, one goal of our study was to produce biocompatible AuNPs using biological methods that are simple, nontoxic, biocompatible, and environmentally friendly. Next, we aimed to assess the antioxidative effect of AuNPs against oxidative stress induced by cold and heat in Escherichia coli, which is a suitable model for stress responses involving AuNPs. The response of aerobically grown E. coli cells to cold and heat stress was found to be similar to the oxidative stress response. Upon exposure to cold and heat stress, the viability and metabolic activity of E. coli was significantly reduced compared to the control. In addition, levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and leakage of proteins and sugars were significantly elevated, and the levels of lactate dehydrogenase activity (LDH) and adenosine triphosphate (ATP) significantly lowered compared to in the control. Concomitantly, AuNPs ameliorated cold and heat-induced oxidative stress responses by increasing the expression of antioxidants, including glutathione (GSH), glutathione S-transferase (GST), super oxide dismutase (SOD), and catalase (CAT). These consistent physiology and biochemical data suggest that AuNPs can ameliorate cold and heat stress-induced oxidative damage in E. coli. Our results indicate that AuNPs may be effective antioxidants. However, further studies are needed to confirm the role of AuNPs as antioxidative agents, as well as their mechanism of action.
College of Biological and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan 430023, China. zhangxf9465@163.com.
Xi-Feng
XF
Zhang
Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of Shandong, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China. shenwei427@163.com.
Wei
W
Shen
Department of Stem Cell and Regenerative Biology, Konkuk University, Seoul 143-701, Korea. sangiliyandi@konkuk.ac.kr.
Sangiliyandi
S
Gurunathan
D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000494:pharmacology*; D003080:Cold Temperature / Q000009:adverse effects; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D006046:Gold; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D053768:Metal Nanoparticles / Q000008:administration & dosage / Q000737:chemistry*; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism
D000975:Antioxidants; D001672:Biocompatible Materials; D017382:Reactive Oxygen Species; D006046:Gold
Escherichia coli; antioxidants; cold stress; gold nanoparticles; heat stress; oxidative stress