Stress induced cross-protection against environmental challenges on prokaryotic and eukaryotic microbes

Abstract

Prokaryotic and eukaryotic microbes thrive successfully in stressful environments such as high osmolarity, acidic or alkali, solar heat and u.v. radiation, nutrient starvation, oxidative stress, and several others. To live under these continuous stress conditions, these microbes must have mechanisms to protect their proteins, membranes, and nucleic acids, as well as other mechanisms that repair nucleic acids. The stress responses in bacteria are controlled by master regulators, which include alternative sigma factors, such as RpoS and RpoH. The sigma factor RpoS integrates multiple signals, such as the general stress response regulators and the sigma factor RpoH regulates the heat shock proteins. These response pathways extensively overlap and are induced to various extents by the same environmental stresses. In eukaryotes, two major pathways regulate the stress responses: stress proteins, termed heat shock proteins (HSP), which appear to be required only for growth during moderate stress, and stress response elements (STRE), which are induced by different stress conditions and these elements result in the acquisition of a tolerant state towards any stress condition. In this review, the mechanisms of stress resistance between prokaryotic and eukaryotic microbes will be described and compared.

Reduction of the Temperature Sensitivity of Halomonas hydrothermalis by Iron Starvation Combined with Microaerobic Conditions

“…It is plausible that, in the present study, iron starvation and microaerobic conditions exerted a compound influence on H. hydrothermalis tolerance of differences in temperature and salinities either directly or as a consequence of secondary stress responses (such as those induced by a reduction in pH under CO 2 -enriched conditions; see Table S1 in the supplemental material). Indeed, exposure to a given extreme can frequently confer cross-protection against other environmental stressors in both prokaryotes and eukaryotes, due to overlapping physiological adaptations and stress-response networks (8,60,(62)(63)(64)(65).…”

Cold activity and tolerance of the entomopathogenic fungus Tolypocladium spp. to UV-B irradiation and heat

“…These differences may be due to thermometer accuracy, because even few decimals in degrees Celsius would change the conidial viability (Rangel et al, 2005b). Another possibility to explain these differences is due to culture medium which often changes the tolerance to stress; less nutritive or nutrient poor medium affords higher tolerance to UV-B radiation and heat (Rangel, 2011;Rangel et al, 2006aRangel et al, , 2008Rangel et al, , 2004Rangel et al, , 2011. We did not use yeast extract to supplement the potato dextrose agar medium, which was used before (Rangel et al, 2005b(Rangel et al, , 2006b.…”

Thermal Resistance and Gene Expression of both Desiccation-Adapted and Rehydrated Salmonella enterica Serovar Typhimurium Cells in Aged Broiler Litter

“…The stress responses in bacteria are controlled by master regulators, which include alternative sigma factors such as RpoS (22). van Hoek et al (23) reported that a fully functional RpoS system is an advantage for the long-term survival of Escherichia coli O157 in the manure-amended soil environment.…”