Effects of metal ions and hydrogen peroxide on the phenotype of yeast hom6Δ mutant. (21st November 2014)

• Record Type: Journal Article
• Authors: Tun, N.M.; Lennon, B.R.; O'Doherty, P.J.; Johnson, A.J.; Petersingham, G.; Bailey, T.D.; Kersaitis, C.; Wu, M.J.
• Is Part Of: Letters in applied microbiology. Volume 60:Number 1(2015:Jan.)
• Page Start: 20
• Page End: 26
• Publication Date: 2014-11-21
• Subjects: Microbiology -- Periodicals; 660.62
• DOI: 10.1111/lam.12336
• Languages: English
• ISSNs: 0266-8254

Abstract

<abstract abstract-type="main" id="lam12336-abs-0001"> <title>Abstract</title> <sec id="lam12336-sec-0001" sec-type="section"> <p> <italic>HOM6</italic> is a major gene in the aspartate pathway which leads to biosynthesis of threonine and methionine. The phenotypes of the gene deletion mutant (<italic>hom6</italic>∆) in a variety of cultural conditions have previously provided meaningful insights into the biological roles of <italic>HOM6</italic> and its upstream intermediate metabolites. Here, we conducted a survey on a spectrum of metal ions for their effect on the aspartate pathway and broader sulphur metabolism. We show that manganese (Mn<sup>2+</sup>) promoted the growth of <italic>hom6∆</italic> under both anaerobic and aerobic conditions. Unexpectedly, 4 mmol l<sup>−1</sup> hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), a dose normally causing temporary cell growth arrest, enhanced the growth of <italic>hom6∆</italic> under the anaerobic condition only, while it had no effect on the wild type strain BY4743. We propose that Mn<sup>2+</sup> and H<sub>2</sub>O<sub>2</sub> promote the growth of <italic>hom6∆</italic> by reducing the accumulation of the toxic intermediate metabolite—aspartate <italic>β</italic>‐semialdehyde, via directing the aspartate pathway to the central sugar metabolism–tricarboxylic acid cycle.</p> </sec> <sec id="lam12336-sec-0002" sec-type="section"> <title>Significance and Impact of the Study</title> <p>This study focuses on the yeast strain which lacks homoserine dehydrogenase encoded by <italic>HOM6</italic> gene in aspartate metabolism. The <italic>HOM6</italic>‐deletion mutant (<italic>hom6</italic>Δ) was analysed in the context of varying environmental parameters such as metal ions and oxidants, under anaerobic and aerobic conditions. We demonstrated that both manganese and hydrogen peroxide can promote the growth of <italic>hom6</italic>Δ, with the latter exerting such effect only under anaerobic condition. The findings are relevant to the research areas of ageing and anti‐fungal drug development. It highlights the importance of interactions between gene expression and environmental factors as well as culture conditions.</p> </sec> </abstract>