The cysS gene (ncgl0127) of Corynebacterium glutamicum is required for sulfur assimilation and affects oxidative stress-responsive cysteine import.

The OsnR protein functions as a transcriptional repressor of genes involved in redox-dependent stress responses. Here, we studied Corynebacterium glutamicum ORF ncgl0127 (referred to as cysS in this study), one of the target genes of OsnR, to reveal its role in osnR-mediated stress responses. The ΔcysS strain was found to be a cysteine auxotroph, and the transcription levels of the sulfur assimilatory genes and cysR, the master regulatory gene for sulfur assimilation, were low in this strain. Complementation of the strain with cysR transformed the strain into a cysteine prototroph. Cells challenged with oxidants or cysteine showed transcriptional stimulation of the cysS gene and decreased transcription of the ncgl2463 gene, which encodes a cysteine/cystine importer. The transcription of the ncgl2463 gene was increased in the ΔcysS strain and further stimulated by cysteine. Unlike the wild-type strain, ΔcysS cells grown with an excess amount of cysteine showed an oxidant- and alkylating agent-resistant phenotype, suggesting deregulated cysteine import. Collectively, our data suggest that the cysS gene plays a positive role in sulfur assimilation and a negative role in cysteine import, in particular in cells under oxidative stress.

Is the male disadvantage real? Cross-national variations in sex gaps in COVID-19 incidence and mortality.

ABSTRACTAlthough the excess male mortality from COVID-19 is well-known, the variations in sex gaps in incidence and mortality across countries and the sources of such variations are not well understood. This study explored the patterns and the sources of variation in the sex gap in COVID-19 incidence and mortality rates across 100 countries where sex-disaggregated cases and deaths were available as of September 2020. Our results show that there is generally a male disadvantage in both incidence and mortality; however, COVID-19 incidence exhibited a lower male disadvantage (1.2 times higher risk for males) than COVID-19 mortality (1.5 times higher risk for males). The extent of male disadvantages in COVID-19 outcomes across countries varied by societal gender inequalities and behavioural factors. Greater gender equality, both socially and behaviourally, was associated with more equal COVID-19 incidence and mortality between men and women. The findings imply that male disadvantages in COVID-19 outcomes, particularly incidence, are socially determined, whereas further investigation is needed to understand behavioural and biological elements yielding a male disadvantage in mortality.