marinintestina IK-1. This work was partly supported by the National Institute of Polar Research. T.N. and R.H. contributed equally to this work. “
“Staphylococcus aureus MrgA (encoded by mrgA) belongs to the Dps family of proteins, which play important roles in coping with various
stresses. The staphylococcal mrgA gene is specifically expressed under oxidative stress conditions and is one of the most highly induced genes during phagocytic killing by macrophages. We previously reported that mrgA is essential for oxidative stress resistance, and can cause nucleoid compaction. However, whether nucleoid compaction by itself would contribute to oxidative stress resistance was hard to determine, because Dps family proteins generally have ferroxidase activity to prevent hydroxyl radical formation via the Fenton reaction. Neratinib cost In this study, we resolved the crystal structure of MrgA and conducted mutation analysis of Asp56 and Glu60, which are located at the expected ferroxidase centre. In the strain expressing
Asp56Ala/Glu60Ala MrgA (termed MrgA*), MrgA* retained dodecamer formation and nucleoid compaction ability. By contrast, the Palbociclib ferroxidase activity of MrgA* decreased by about half. Viability of the mrgA* strain was as low as the mrgA null mutant in oxidative stress and phagocytic killing assays. These results suggest that nucleoid compaction by itself is insufficient for oxidative stress resistance, and Asp56 and Glu60 constitute essential molecular sites in MrgA
for oxidative stress resistance and survival against phagocytic killing. “
“Patients suffering from major depression have repeatedly been reported to have dysregulations in hypothalamus–pituitary–adrenal (HPA) axis activity along with deficits in cognitive processes related to hippocampal and prefrontal cortex (PFC) malfunction. Here, we utilized three mouse lines selectively bred for high (HR), Galactosylceramidase intermediate, or low (LR) stress reactivity, determined by the corticosterone response to a psychological stressor, probing the behavioral and functional consequences of increased vs. decreased HPA axis reactivity on the hippocampus and PFC. We assessed performance in hippocampus- and PFC-dependent tasks and determined the volume, basal activity, and neuronal integrity of the hippocampus and PFC using in vivo manganese-enhanced magnetic resonance imaging and proton magnetic resonance spectroscopy. The hippocampal proteomes of HR and LR mice were also compared using two-dimensional gel electrophoresis and mass spectrometry. HR mice were found to have deficits in the performance of hippocampus- and PFC-dependent tests and showed decreased N-acetylaspartate levels in the right dorsal hippocampus and PFC. In addition, the basal activity of the hippocampus, as assessed by manganese-enhanced magnetic resonance imaging, was reduced in HR mice. The three mouse lines, however, did not differ in hippocampal volume.