Fermentative 2‐carbon metabolism produces carcinogenic levels of acetaldehyde in Candida albicans

Summary Acetaldehyde is a carcinogenic product of alcohol fermentation and metabolism in microbes associated with cancers of the upper digestive tract. In yeast acetaldehyde is a by‐product of the pyruvate bypass that converts pyruvate into acetyl‐CoA during fermentation. The aims of our study were: i) to determine the levels of acetaldehyde produced by C. albicans in the presence of glucose in low oxygen tension in vitro; ii) to analyze the expression levels of genes involved in the pyruvate‐bypass and acetaldehyde production; iii) to analyze whether any correlations exist between acetaldehyde levels, Adh enzyme activity or expression of the genes involved in the pyruvate‐bypass. C. albicans strains were isolated from patients with oral squamous cell carcinoma (n=5), APECED patients with chronic oral candidosis (n=5), and control patients (n=5). The acetaldehyde and ethanol production by these isolates grown under low oxygen tension in the presence of glucose were determined, and the expression of alcohol dehydrogenase (ADH1 and ADH2), pyruvate decarboxylase (PDC11), aldehyde dehydrogenase (ALD6) and acetyl CoA synthetase (ACS1 and ACS2) and Adh enzyme activity were analyzed. C. albicans isolates produced high levels of acetaldehyde from glucose under low oxygen tension. The acetaldehyde levels did not correlate with the expression of ADH1, ADH2 or PDC11 but correlated with the expression of down‐stream genes ALD6 and ACS1. Significant differences in the gene expre...
Source: Oral Microbiology and Immunology - Category: Microbiology Authors: Tags: Original Article Source Type: research