Increase in Oxidative Stress at Low Temperature in an Antarctic Bacterium

Abstract

Association between cold stress and oxidative stress was demonstrated by measuring the activity of two antioxidant enzymes and the level of free radicals generated in two batches of cells of an Antarctic bacterium Pseudomonas fluorescens MTCC 667, grown at 22 and 4°C. Increase in oxidative stress in cells grown at low temperature was evidenced by increase in the activity of an enzyme and also in the amount of free radicals generated, in the cold-grown cells. The association between cold stress and oxidative stress demonstrated in this investigation bolsters the concept of interlinked stress response in bacteria.

Cold Stress in Antarctic Fungi Targets Enzymes of the Glycolytic Pathway and Tricarboxylic Acid Cycle

“…Castellano et al (10) suggested that S-glutathionylated superoxide dismutase (SOD) from psychrophilic eubacterium Pseudoalteromonas haloplanktis could represent a further cold-adaptation strategy to improve the antioxidant cellular defence mechanism during cold shock. Low temperature treatment of Antarctic bacterium Pseudomonas fluorescens MTCC 667 caused increase in the level of ROS and antioxidant enzyme activities (12). Our previous investigations showed a relationship between cold stress and oxidative stress in filamentous fungi isolated from different regions of Antarctica (18,19,39).…”

Transient Cold Shock Induces Oxidative Stress Events in Antarctic Fungi

“…Very little information is available on the oxidative cell response of microorganisms from cold habitats (Gocheva et al, 2006(Gocheva et al, , 2009Tosi et al, 2010;Chattopadhyay et al, 2011;Nichols et al, 1999). Even less is known concerning filamentous fungi from the Bulgarian Antarctic area.…”

“…A similar direct analysis of ROS content in fungal cells has not often been reported. Chattopadhyay et al (2011) reported that the production of free radicals in the Antarctic bacterium Pseudomonas fluorescens MTCC 667 was higher at low temperature compared to that at 22°C. When cells are exposed to low temperature, the rate of enzymatic reactions decreases, leading to a decrease in the demand for ATP and an accumulation of electrons at certain points in the respiratory chain.…”

“…Enhanced SOD and CAT activities have been associated with the induced resistance of fungi to different stress factors (Manfredini et al, 2005;Li et al, 2009;Belozerskaya et al, 2010;Chattopadhyay et al, 2011). Both activities are involved in superoxide radical and hydrogen peroxide scavenging.…”

“…To scavenge ROS and prevent damage, all aerobic cells have evolved a complex defence system consisting of both low molecular mass scavengers and high molecular mass antioxidants, particularly, antioxidant enzymes, such as superoxide dismutase (SOD) and catalase (CAT) (Fridovich, 1998). Thus, antioxidant defence may play a significant role in the microbial survival mechanism under extremely cold conditions (Chattopadhyay, 2002;Chattopadhyay et al, 2011).…”