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Structural analysis of the BRM2 gene involved in melanin biosynthesis of the Japanese pear pathotype of Alternaria alternata suggested that this gene encodes 1,3,8-trihydroxynaphthalene reductase. Targeted disruption of the BRM2 gene did not affect pathogenicity, vegetative growth, or the number of conidia produced. Targeted disruption, however, did reduce conidial size and septal number, suggesting that melanin is associated with conidial development. The conidia of brm2 mutant transformants were more sensitive to UV light than those of the wild type, demonstrating that melanin confers UV tolerance.  相似文献   
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Atypical cell surface lipoprotein-binding proteins of 105 kDa and 130 kDa are present in membranes of vascular smooth muscle cells. We recently identified the 105 kDa protein from human aortic media as T-cadherin, an unusual glycosylphosphatidylinositol (GPI)-anchored member of the cadherin family of cell adhesion proteins. The goal of the present study was to determine the identity of 130 kDa lipoprotein-binding protein of smooth muscle cells. We applied different approaches that included protein sequencing of purified protein from human aortic media, the use of human T-cadherin peptide-specific antisera, and enzymatic treatment of cultured cells with trypsin and GPI-specific phospholipase C. Our results indicate that the 130 kDa protein is a partially processed form of T-cadherin which is attached to the membrane surface of smooth muscle cells via a GPI anchor and contains uncleaved N-terminal propeptide sequence. Our data disclose that, in contrast to classical cadherins, T-cadherin is expressed on the cell surface in both its precursor (130 kDa) and mature (105 kDa) forms.  相似文献   
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为准确计算濮城油田沙一、二段原始含油饱和度,从水基泥浆取心井法、电阻率法、阿尔奇公式法、物性公式法、粒度中值经验公式法、驱动压力法、毛管压力法等7个方面进行研究,并探讨各方法之间的异同点,进而进取较合理的油藏含油饱和度值。  相似文献   
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Endotoxin activates white blood cells and complement and produces a spectrum of clinical syndromes ranging from fever to septic shock. Although production of endogenous endotoxemia during cardiopulmonary bypass (CPB) has recently been reported, the role of hypothermia on endotoxemia is not clear. In this study, we evaluated the effects of moderate (24-28 degrees C) and mild (32-34 degrees C) hypothermia on blood endotoxin levels. The study population consisted of 20 patients who underwent coronary artery bypass grafting (CABG) with CPB. Moderate systemic hypothermia was applied during aortic cross-clamping in ten patients (group 1) and mild hypothermia in the remaining ten patients (group 2). The mean rectal temperatures were 26.8 +/- 1.2 degrees C in group 1 and 33.8 +/- 0.8 degrees C in group 2. The blood samples for endotoxin level measurements were obtained before CPB, during aortic cross-clamping, immediately after the release of the cross-clamp, 20 minutes after the release of the cross-clamp, after CPB, and 2 hours postoperatively. There were no endotoxins in any of the samples before CPB, but it was detected after CPB in both groups. The endotoxin levels were significantly higher in group 1 than in group 2. The present study suggests that when hypothermia is the technique of choice, the deleterious effects of endotoxemia on patients with comorbidity must be considered.  相似文献   
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