Journal of Microbiology

Research Support, Non-U.S. Gov't

Adaptive Stress Response to Menadione-Induced Oxidative Stress in Saccharomyces cerevisiae KNU5377: Il-Sup Kim , Ho-Yong Sohn , Ingnyol Jin; J. Microbiol. 2011;49(5):816-823. Published online November 9, 2011; DOI: https://doi.org/10.1007/s12275-011-1154-6

Abstract: The molecular mechanisms involved in the ability of yeast cells to adapt and respond to oxidative stress are of great interest to the pharmaceutical, medical, food, and fermentation industries. In this study, we investigated the time-dependent, cellular redox homeostasis ability to adapt to menadione-induced oxidative stress, using biochemical and proteomic approaches in Saccharomyces cerevisiae KNU5377. Time-dependent cell viability was inversely proportional to endogenous amounts of ROS measured by a fluorescence assay with 2′,7′-dichlorofluorescin diacetate (DCFHDA), and was hypersensitive when cells were exposed to the compound for 60 min. Morphological changes, protein oxidation and lipid peroxidation were also observed. To overcome the unfavorable conditions due to the presence of menadione, yeast cells activated a variety of cell rescue proteins including antioxidant enzymes, molecular chaperones, energy-generating metabolic enzymes, and antioxidant molecules such as trehalose. Thus, these results show that menadione causes ROS generation and high accumulation of cellular ROS levels, which affects cell viability and cell morphology and there is a correlation between resistance to menadione and the high induction of cell rescue proteins after cells enter into this physiological state, which provides a clue about the complex and dynamic stress response in yeast cells.

Cloning and Sequencing Analysis of cadC Encoding Transcriptional Activator CadC from Salmonella typhimurium: Bae Hoon Kim , Ho Jeong Lee , In Soo Lee , Sung Ho Bang; J. Microbiol. 2001;39(2):109-115.

Abstract: Salmonella typhimurium possesses a cad operon, which contributes to an adaptive response against an acidifying environment. In Escherichia coli, the activation of the cad operon is dependent on cadC, which is located upstream of the operon. However, the activator of cad operon in S. typhimurium has not been known until now. In this study, we selected a putative cadC mutant by trasposon mutagenesis and cloned the cadC of S. typhimurium. Moreover, the cadC mutant was complemented by cadC clone. The cadC gene from S. typhimurium LT-2 consists of 1539 bp encoding a polypeptide ob 512 amino acids, and shows sequence similarity to cadC of E. coli with 53% identity and 67% similarity. The hydrophobicity profile of the S. typhimurim CadC sequence is very similar to E. coli CadC.

Search