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The initiation reactions in surfactin biosynthesis by Bacillus subtilis OKB 105 and the specific role of the SrfD protein are investigated. The SrfD protein efficiently supports this process as a thioesterase/actyltransferase enzyme by mediating the transfer of the fatty acid substrate to the Glu-module and stimulating beta-hydroxyacyl-glutamate formation.

Objective: Left ventricular assist devices (LVAD) are used to ‘bridge’ patients with end-stage heart failure to transplantation. After long-term LVAD support, ventricular function may partially recover, a process called ‘reverse remodeling’. As several kinase-mediated signal transduction pathways have been implicated in the development of cardiac hypertrophy and failure, we examined the activities of the Erks, MEKs, Akt, GSK-3β, p70S6K, JNKs and p38 under LVAD support as well as during single myocyte strain and whole heart stretch. Methods: Western blotting and immunohistochemistry were performed using phospho-specific antibodies in matched samples from ten patients with end-stage heart failure before and after LVAD. Cyclic strain was performed in rat neonatal cardiac myocytes, and tensile stretch applied to Langendorff-perfused mouse hearts via a left ventricular balloon. Results: The activity of Erks and Akt in failing hearts dramatically decreased after LVAD support, while that of GSK-3β increased. There was an endo/epicardial gradient for Erk activity which persisted after LVAD despite the reduction of total Erk activity. TUNEL-positivity and myocyte size decreased after LVAD, but independently of changes in kinase activity. In cardiomyocytes and Langendorff-perfused mouse hearts both strain/stretch and its relief regulated the activities of Erks, Akt, and GSK-3β. Conclusion: Erks and Akt/GSK-3β are highly responsive to myocyte stretch in vitro and in vivo, and may be sensitive molecular parameters of ‘reverse remodeling’ under LVAD support. [Copyright &y& Elsevier]

Objective: Left ventricular assist devices (LVAD) have been used to ‘bridge’ patients with end-stage heart failure to transplantation. Although several reports have suggested that the native ventricular function recovers after long-term LVAD support, a process called ‘reverse remodeling’, the underlying biological mechanisms are still unknown. As the transcription factor nuclear factor-κB (NF-κB) has been shown to be active in the failing human heart, we examined whether its activity is altered under LVAD support, and may thus contribute to the dynamic process of ‘reverse remodeling’. Methods: The activity of NF-κB was studied in 16 patients with end-stage heart failure (eight with dilated cardiomyopathy, six with ischemic heart disease, one with myocarditis, and one with congenital heart disease) before and after LVAD support by immunohistochemistry using an antibody against active NF-κB. Gel-shifts for NF-κB DNA-binding activity were performed with paired human myocardial tissue from four patients. The mean cardiomyocyte diameter before and after mechanical unloading was measured with an image analyzer system. Results: 15 patients out of 16 showed a significant decrease in the number of NF-κB positive cardiomyocyte nuclei after LVAD support in the left ventricular myocardium. The NF-κB DNA-binding activity also decreased after LVAD support as measured by gel-shift analysis. While the number of positive cardiomyocytes was significantly higher in the subendocardium than in the subepicardium at the time of LVAD implantation, this difference was no longer present at the time of LVAD explantation. The diameter of cardiomyocytes in the left ventricle decreased significantly as a parameter of structural reverse remodeling. Conclusion: LVAD support decreases the extent of NF-κB activation in failing human hearts, suggesting that NF-κB may be involved in the process of ‘reverse remodeling’. [ABSTRACT FROM PUBLISHER]

Objective: Left ventricular assist devices (LVAD) have been used to 'bridge' patients with end-stage heart failure to transplantation. Although several reports have suggested that the native ventricular function recovers after long-term LVAD support, a process called 'reverse remodeling', the underlying biological mechanisms are still unknown. As the transcription factor nuclear factor-kappaB (NF-kappaB) has been shown to be active in the failing human heart, we examined whether its activity is altered under LVAD support, and may thus contribute to the dynamic process of 'reverse remodeling'., Methods: The activity of NF-kappaB was studied in 16 patients with end-stage heart failure (eight with dilated cardiomyopathy, six with ischemic heart disease, one with myocarditis, and one with congenital heart disease) before and after LVAD support by immunohistochemistry using an antibody against active NF-kappaB. Gel-shifts for NF-kappaB DNA-binding activity were performed with paired human myocardial tissue from four patients. The mean cardiomyocyte diameter before and after mechanical unloading was measured with an image analyzer system., Results: 15 patients out of 16 showed a significant decrease in the number of NF-kappaB positive cardiomyocyte nuclei after LVAD support in the left ventricular myocardium. The NF-kappaB DNA-binding activity also decreased after LVAD support as measured by gel-shift analysis. While the number of positive cardiomyocytes was significantly higher in the subendocardium than in the subepicardium at the time of LVAD implantation, this difference was no longer present at the time of LVAD explantation. The diameter of cardiomyocytes in the left ventricle decreased significantly as a parameter of structural reverse remodeling., Conclusion: LVAD support decreases the extent of NF-kappaB activation in failing human hearts, suggesting that NF-kappaB may be involved in the process of 'reverse remodeling'.