The secondary electron acceptor of photosystem I in Gloeobacter violaceus PCC 7421 is menaquinone-4 that is synthesized by a unique but unknown pathway

The secondary electron acceptor of photosystem (PS) I in the cyanobacterium Gloeobacter violaceus PCC 7421 was identified as menaquinone-4 (MQ-4) by comparing high performance liquid chromatograms and absorption spectra with an authentic compound. The MQ-4 content was estimated to be two molecules per one molecule of chlorophyll (Chl) a′, a constituent of P700. Comparative genomic analyses showed that six of eight men genes, encoding phylloquinone/MQ biosynthetic enzymes, are missing from the G. violaceus genome. Since G. violaceus clearly synthesizes MQ-4, the combined results indicate that this cyanobacterium must have a novel pathway for the synthesis of 1,4-dihydroxy-2-naphthoic acid

Expression of monocyte chemoattractant protein-1 in idiopathic dilated cardiomyopathy

Immunological factors have been involved in the pathogenesis of dilated cardiomyopathy (DCM). The cytotoxic action of macrophages is one of the main factors causing cardiac myocyte damage. Monocyte chemoattractant protein-1 (MCP-1) is a major signal for the accumulation of monocytes/macrophages. We examined whether MCP-1 was expressed in the myocardium of DCM patients and whether the expression level was correlated with the degree of impairment of cardiac function. The expression of MCP-1 in the myocardium was determined by immunohistochemistry in endomyocardial biopsy samples from 13 patients. The expression of MCP-1 was found in all myocardial samples from DCM patients but not in those from control subjects. Positive staining for MCP-1 was distinct in cardiac myocytes, interstitium and infiltrating cells. Semi-quantitative analysis revealed that the expression of MCP-1 was inversely correlated with left ventricular ejection fraction. In conclusion, the expression level of MCP-1 in the myocardium was correlated with the degree of impairment of cardiac function in patients with DCM.</p

Arterial Stiffening is Associated with Exercise Intolerance and Hyperventilatory Response in Patients with Coronary Artery Disease

Exercise intolerance is a common feature of patients with coronary artery disease (CAD). Arterial stiffness is increased in CAD patients; however, the association between arterial stiffness and exercise capacity of CAD patients has not been fully clarified. In this study, we investigated the association between arterial stiffness and the exercise capacity of 62 CAD patients (67 ± 7 yo, 49 men). The patients underwent symptom-limited cardiopulmonary exercise testing and measurement of pulse wave velocity (PWV). The patients were divided into the high-PWV group (n = 31) and the low-PWV group (n = 31), according to the median PWV (1622 cm/sec). In exercise testing, the peak VO 2 was lower in the high-PWV group than in the low-PWV group. VE/VCO 2 slope was higher and the time to ST depression was shorter in the high-PWV group than in the low-PWV group. Multivariate analysis results showed that PWV significantly correlated with peak VO 2 as well as sex. PWV also significantly correlated with time to ST depression and VE/VCO 2 slope. In conclusion, patients with high PWV had lower exercise capacity than patients with low PWV. A low myocardial ischemia threshold, as well as an enhancement of the ventilatory response to exercise, was also found in patients with high PWV