Comparison of enzymatic antioxidant defence systems in different metabolic types of yeasts

Abstract

The enzymatic defence system in the 2 yeasts Kluyveromyces marxianus and Rhodotorula glutinis, differing in their mode of oxygen uptake and energy generation, was characterized and compared with the well-studied facultatively fermentative Crabtree-positive Saccharomyces cerevisiae strain. Twofold higher superoxide dismutase (SOD) and catalase activities were detected in K. marxianus and R. glutinis when cells were cultured on glucose. Further increases of 10%-15% in SOD activity and 30%-50% in catalase were measured in all studied yeasts strains after transfer to media containing ethanol. An evaluation of the ratio of Cu/Zn SOD / Mn SOD was performed as a measure of the oxidative metabolism. A 20% decrease was observed when the respiratory source of energy was ethanol, with the lowest ratio being observed for the oxidative type of K. marxianus yeasts. Electrophoretic analysis revealed that all tested strains possess active Cu/Zn and Mn SODs. A reverse electrophoretic mobility pattern of K. marxianus and R. glutinis SOD enzymes was observed in comparison with the same couple in S. cerevisiae. The investigation of electrophoretic profile of catalase enzymes showed that alongside their different taxonomic status and fermentative capacity, all tested strains possess 2 separate catalases. The role of antioxidant enzymes in preventing oxidant-induced cytotoxicity (treatment with hydrogen peroxide, paraquat, and menadione) was shown.

Investigation of the simultaneous production of superoxide dismutase and catalase enzymes fromRhodotorula glutinisunder different culture conditions

“…In terms of SOD activities, 90 U/mg protein was reported with Aspergillus niger (Tsekova and Todorova 2002), while 44.3 U/mg with Cordyceps militaris (Wang et al 2005) and 150 U/mg with Stenotrophomonas maltophilia (Tsekova and Todorova 2002), most of which were exposed to an oxidative stress inducer. Using R. glutinis Koleva et al (2008) reported 28 U/mg protein of SOD activity also in ethanol-containing medium, whereas we achieved 125 U/mg protein SOD activity with glycerol-containing medium. Th ese comparative results seem to be striking, since they were obtained without additional oxidative stress.…”

“…In terms of CAT activities, 66.9 U/mg was obtained with Escherichia coli B (Misra and H ö fer 1975), while 93.7 NU/mg with Cordyceps militaris (Wang et al 2005); additionally, 90 NU/mg protein was obtained with Stenotrophomonas maltophilia (L ü et al 2008). Using R. glutinis, Koleva et al (2008) reached 22 U/mg protein of CAT activity in ethanol-containing medium while we obtained 113 U/mg protein CAT activity in glycerol-containing medium. In terms of SOD activities, 90 U/mg protein was reported with Aspergillus niger (Tsekova and Todorova 2002), while 44.3 U/mg with Cordyceps militaris (Wang et al 2005) and 150 U/mg with Stenotrophomonas maltophilia (Tsekova and Todorova 2002), most of which were exposed to an oxidative stress inducer.…”

“…On the other hand, it was a poor source for CAT and SOD activities, similar to UYM. For a variety of yeasts, glucose was reported to be responsible for low or non-detectable expression levels of many genes that encode for proteins involved in antioxidant defence (Koleva et al 2008). Glucose was also reported to suppress the synthesis of CAT and SOD in Escherichia coli (Hassan and Fridovich 1977).…”

Targeting Genes of Cd Induced Oxidative Stress Response in Yeasts

“…Recent genetic and biochemical experiments revealed that in Rhodotorula mucilaginosa and Rhodotorula graminis changes in the structure of the SOD1 gene generate stop codons at different positions, which correlates with the absence of peptides or active proteins in the cells. however, for other basidiomycetous yeasts, such as R. glutinis and U. puniceus, the cloned nucleotide sequence contains all necessary information to produce a functional protein (16,20). Moreover, studies with S. cerevisiae cells lacking the cytosolic Sod1, showed that cadmium was removed twice as effectively as in the control strain, while those deficient in the mitochondrial Sod2 exhibited poor metal absorption (1).…”

Superoxide Dismutase Enzymes in Oxidative Type YeastH. Polymorpha

“…(16) The thermostability of SOD enzymes was analyzed in the range of 30°C, 50°C and 75°C. A spectrophotometrical analysis showed that average 21.55% of the total enzyme activity remains after treatment with 75C for 10 minutes when cells were cultivated on methanol, glucose and glycerol.…”