Kluyveromyces lactis: A Suitable Yeast Model to Study Cellular Defense Mechanisms against Hypoxia-Induced Oxidative Stress
Table 3
Main differences reported hitherto between K. lactis and S. cerevisiae, two alternative unicellular eukaryote models for hypoxic and oxidative stress responses.
K. lactis
S. cerevisiae
Crabtree effect
Negative
Positive
Glucose catabolism in aerobic conditions
Mainly respiratory
Mainly fermentative
Ratio PPP/glycolysis for glucose catabolism
High
Low
Reoxidation of NADPH from PPP
Mainly by mitochondrial alternative external dehydrogenases
Mainly by cytosolic NADPH oxidoreductases
Catabolic repression of respiration
Low
High
Respiratory capacity
Unlimited
Limited
Petite phenotype
Positive in specific mutant genetic backgrounds
Positive
Caloric restriction increases longevity
No
Yes
Aerobic/hypoxic gene pairs
Absent
Present
Upregulated by hypoxia
Genes related to ergosterol synthesis, cell wall composition, and glycolytic genes. OS genes: CUP1 and CUP2, HSP12, FMP46 and GRE1, and SOD1.
Genes from the heme biosynthetic pathway, pyruvate decarboxylase, and lipid biosynthesis. OS genes: KlOYE2, KlGSH1. This response is highly dependent on the relative flux of glucose through glycolysis or PPP
