Gene expression profiling in Saccharomyces cerevisiae grown at different specific gravity environments

The global gene expression profiles of industrial strains of Saccharomyces cerevisiae responding to nitrogen deficiency and very high sugar concentrations stresses were determined by oligonucleotide microarray analysis of ~ 6200 yeast open reading frames. Genomics analysis showed that 400 genes in S. cerevisiae was differentially expressed by more than 1.5-fold compared with controls at late-logarithmic phase of fermentation, as the yeast adapted to changing nutritional, environmental and physiological conditions. The genes of many pathways are regulated in a highly coordinated manner. The repressed expression of GDH1 and up-regulation of ARO10 within the contrast of Q270/Q10 indicated high energy demanding of yeast cells under high sugar stress. Activities of G3P shuttle indicated that under very high gravity environment, sufficient assimilatory nitrogen enhances yeast’s ability of redox balancing, and therefore higher stress-tolerance and higher fermentation efficiency of yeast. Under contrast W270/Q270, the up-regulation of DUR1,2 responsible for urea degradation induces the glutamate biosynthesis and the consumption of -ketoglutarate. This may indicate that higher nitrogen level would enable higher activities in the TCA cycle, and therefore generate more energy for biosynthesis and yeast cell proliferation under very high gravity fermentation conditions. Nitrogen metabolism was also stimulated by high nitrogen level when yeast was grown in very high gravity environment.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Chemical Engineering

Grantor

University of Saskatchewan

Year dc:date.issued

2007

Author dc:creator

• Yang, Danmei

Advisor dc:contributor.advisor

• Lin, Yen-Han

Committee members dc:contributor.committeemember

• Wu, Fang-Xiang
• Evitts, Richard W.
• Nemati, Mehdi

• metabolic pathway
• Saccharomyces cerevisiae
• gene expression
• microarray

Language dc:language.iso

en_US

Handle dc:identifier.uri

https://hdl.handle.net/10388/etd-12042007-115558

OAI identifier oai:identifier

oai:harvest.usask.ca:10388/etd-12042007-115558