Self-employment, depression, and older individuals: A cross-country study.

BACKGROUND: Self-employment has become an increasingly popular occupational choice, and there are substantial mental health and well-being benefits that can accrue for individuals who remain active and engaged later in life. In this study, we examine the association between reduced depression symptoms and self-employment in aging workers. METHODS: Drawing from The Survey of Health, Ageing and Retirement in Europe (SHARE) data, our study examines a longitudinal sample of 35,717 individuals aged 50 years or older. RESULTS: Our results indicate that self-employment is negatively associated with depression among aging workers. Additionally, we find that this relationship weakens as aging self-employed individuals grow older, and that gender moderates this relationship such that older female self-employed individuals report lower depression symptoms than their male counterparts. LIMITATIONS: Our sample is limited to European workers aged 50 years and older, and as such might have limited generalizability to younger self-employed individuals from other geographic regions. Moreover, although we control for factors that could play a role in the association between depression symptoms and self-employment (e.g. quality of life, personality traits, etc.), additional research will be needed in order to determine the potential mediating and moderating roles such factors might have on this relationship. CONCLUSIONS: The results we present demonstrate the important and nuanced nature between self-employment and depression symptoms in aging workers. These findings call to light the need to continue to foster and develop systems and programs that help to facilitate self-employment for individuals as they transition into older ages.

Converting the NiFeS carbon monoxide dehydrogenase to a hydrogenase and a hydroxylamine reductase.

Substitution of one amino acid for another at the active site of an enzyme usually diminishes or eliminates the activity of the enzyme. In some cases, however, the specificity of the enzyme is changed. In this study, we report that the changing of a metal ligand at the active site of the NiFeS-containing carbon monoxide dehydrogenase (CODH) converts the enzyme to a hydrogenase or a hydroxylamine reductase. CODH with alanine substituted for Cys(531) exhibits substantial uptake hydrogenase activity, and this activity is enhanced by treatment with CO. CODH with valine substituted for His(265) exhibits hydroxylamine reductase activity. Both Cys(531) and His(265) are ligands to the active-site cluster of CODH. Further, CODH with Fe substituted for Ni at the active site acquires hydroxylamine reductase activity.

Hydroxylamine reductase activity of the hybrid cluster protein from Escherichia coli.

The hybrid cluster protein (HCP; formerly termed the prismane protein) has been extensively studied due to its unique spectroscopic properties. Although the structural and spectroscopic characteristics are well defined, its enzymatic function, up to this point, has remained unidentified. While it was proposed that HCP acts in some step of nitrogen metabolism, a specific role for this enzyme remained unknown. Recent studies of HCP purified from Escherichia coli have identified a novel hydroxylamine reductase activity. These data reveal the ability of HCP to reduce hydroxylamine in vitro to form NH(3) and H(2)O. Further biochemical analyses were completed in order to determine the effects of various electron donors, different pH levels, and the presence of CN(-) on in vitro hydroxylamine reduction.