No abstract

Recent studies demonstrated that NADPH oxidase 2 (NOX2) expression in myocardium after ischemia-reperfusion (IR) is significantly upregulated. However, the underlying mechanisms remain unknown. This study aims to determine if nuclear cardiac myosin light chain 2 (MYL2), a well-known regulatory subunit of myosin, functions as a transcription factor to promote NOX2 expression following myocardial IR in a phosphorylation-dependent manner. We examined the phosphorylation status of nuclear MYL2 (p-MYL2) in a rat model of myocardial IR (left main coronary artery subjected to 1 h ligation and 3 h reperfusion) injury, which showed IR injury and upregulated NOX2 expression as expected, accompanied by elevated H₂O₂ and nuclear p-MYL2 levels; these effects were attenuated by inhibition of myosin light chain kinase (MLCK). Next, we explored the functional relationship of nuclear p-MYL2 with NOX2 expression in H9c2 cell model of hypoxia-reoxygenation (HR) injury. In agreement with our in vivo findings, HR treatment increased apoptosis, NOX2 expression, nuclear p-MYL2 and H₂O₂ levels, and the increases were ameliorated by inhibition of MLCK or knockdown of MYL2. Finally, molecular biology techniques including co-immunoprecipitation (Co-IP), chromatin immunoprecipitation (ChIP), DNA pull-down and luciferase reporter gene assay were utilized to decipher the molecular mechanisms. We found that nuclear p-MYL2 binds to the consensus sequence AGCTCC in NOX2 gene promoter, interacts with RNA polymerase II and transcription factor IIB to form a transcription preinitiation complex, and thus activates NOX2 gene transcription. Our results demonstrate that nuclear MYL2 plays an important role in IR injury by transcriptionally upregulating NOX2 expression to enhance oxidative stress in a phosphorylation-dependent manner.

Twenty three strains of oleaginous fungus were screened out from the excess sludge by Sudan black B staining method. After 26s rDNA sequence analysis and comparison, 10 of the strains were found to be Pichia jadini, 9 to be Trichosporon laibachii, and the other 4 to be Galactomyces geotrichum, which belong to molds. We focused on 7 strains of Tri. laibachii, and measured their biomass and oil yield. As a result, Tri. laibachii IEM-17 had the highest biomass, as well as the highest oil yield which reached 21.9%.

In this paper, the effect of heat treatment and strain rate on the tensile property of extruding magnesium alloys 1Mn1Zn4Y is studied by using tensile tests. It can be concluded that because the grain size of the sample with solid solution (T4) is coarser than that of the sample without heat treatment，the elongation and the strength of the specimen treated with solid solution are lower. However, owing to many fine and dispersed particles of the second phase precipitated from the solid solution, the strength of sample treated with solid solution + aging (T6) is the highest.