Deficiency of mouse mast cell protease 4 mitigates cardiac dysfunctions in mice after myocardium infarction

Mouse mast cell protease-4 (mMCP4) is a chymase that has been implicated in cardiovascular diseases, including myocardial infarction (MI). This study tested a direct role of mMCP4 in mouse post-MI cardiac dysfunction and myocardial remodeling. Immunoblot and immunofluorescent double staining demonstrated mMCP4 expression in cardiomyocytes from the infarct zone from mouse heart at 28 day post-MI. At this time point, mMCP4-deficient Mcpt4^?/? mice showed no difference in survival from wild-type (WT) control mice, yet demonstrated smaller infarct size, improved cardiac functions, reduced macrophage content but increased T-cell accumulation in the infarct region compared with those of WT littermates. mMCP4-deficiency also reduced cardiomyocyte apoptosis and expression of TGF-β1, p-Smad2, and p-Smad3 in the infarct region, but did not affect collagen deposition or α-smooth muscle actin expression in the same area. Gelatin gel zymography and immunoblot analysis revealed reduced activities of matrix metalloproteinases and expression of cysteinyl cathepsins in the myocardium, macrophages, and T cells from Mcpt4^?/? mice. Immunoblot analysis also found reduced p-Smad2 and p-Smad3 in the myocardium from Mcpt4^?/? mice, yet fibroblasts from Mcpt4^?/? mice showed comparable levels of p-Smad2 and p-Smad3 to those of WT fibroblasts. Flow cytometry, immunoblot analysis, and immunofluorescent staining demonstrated that mMCP4-deficiency reduced the expression of proapoptotic cathepsins in cardiomyocytes and protected cardiomyocytes from H₂O₂-induced apoptosis. This study established a role of mMCP4 in mouse post-MI dysfunction by regulating myocardial protease expression and cardiomyocyte death without significant impact on myocardial fibrosis or survival post-MI in mice.     

Effect of Cryptobia salmositica-induced anorexia on feeding behavior and immune response in juvenile rainbow trout Oncorhynchus mykiss

At 10 degrees C, rainbow trout Oncorhynchus mykiss (n = 13 per group) infected with Cryptobia salmositica Katz, 1951 became anorexic at 3 wk post-infection (w.p.i.), with feed-intake decreasing significantly from 1.33 to 0.94% body weight (b.w.). Anorexia was most severe at 4 w.p.i. (0.80% b.w.), coinciding with peak parasitemia (9.2 x 10(6) parasites ml blood(-1)) and anemia. At 8 w.p.i., fish had recovered their appetite although they still had contained detectable parasites (6.8 x 10(5) parasites ml(-1)) and were anemic (pack cell volume, PCV, of 24.4%). However at 5 degrees C, anorexia occurred at 5 w.p.i. (0.81% b.w.), and was most severe at 7 w.p.i. (0.40% b.w.). At 8 w.p.i. (0.43% b.w.), fish displayed high parasitemia (4.6 x 10(6) parasites ml(-1)) and low PCV (10.8%). Fish at 5 degrees C had lower gastric evacuation (GE) rates (GE48h) than 10 degrees C fish, however there were no differences between infected and naive fish at both temperatures. Before anorexia, there was no significant correlation between mean share of meal (MSM, a measure of how food was partitioned within a group) and coefficient of variation in feeding but this became significant during anorexia (p = 0.02 and p = 0.0002 at 10 and 5 degrees C respectively). Significant correlations were detected between b.w. and MSM before onset of anorexia at 10 degrees C (p = 0.005) and 5 degrees C (p = 0.02); this was maintained at 10 degrees C (p = 0.001) but not at 5 degrees C (p = 0.98). Fish on an anorexic diet (0.93% b.w.) responded well at 10 degrees C to a live C. salmositica vaccine; this could partly be due to constant antigenic stimulation by the live vaccine.     

Folding and membrane insertion of amyloid‐beta (25–35) peptide and its mutants: Implications for aggregation and neurotoxicity

The mechanisms of interfacial folding and membrane insertion of the Alzheimer's amyloid‐β fragment Aβ(25–35) and its less toxic mutant, N27A‐Aβ(25–35) and more toxic mutant, M35A‐Aβ(25–35), are investigated using replica–exchange molecular dynamics in an implicit water‐membrane environment. This study simulates the processes of interfacial folding and membrane insertion in a spontaneous fashion to identify their general mechanisms. Aβ(25–35) and N27A‐Aβ(25–35) peptides share similar mechanisms: the peptides are first located in the membrane hydrophilic region where their C‐terminal residues form helical structures. The peptides attempt to insert themselves into the membrane hydrophobic region using the C‐terminal or central hydrophobic residues. A small portion of peptides can successfully enter the membrane's hydrophobic core, led by their C‐terminal residues, through the formation of continuous helical structures. No detectable amount of M35A‐Aβ(25–35) peptides appeared to enter the membrane's hydrophobic core. The three studied peptides share a similar helical structure for their C‐terminal five residues, and these residues mainly buried within the membrane's hydrophobic region. In contrast, their N‐terminal properties are markedly different. With respect to the Aβ(25–35), the N27A‐Aβ(25–35) forms a more structured helix and is buried deeper within the membrane, which may result in a lower degree of aggregation and a lower neurotoxicity; in contrast, the less structured and more water‐exposed M35A‐Aβ(25–35) is prone to aggregation and has a higher neurotoxicity. Understanding the mechanisms of Aβ peptide interfacial folding and membrane insertion will provide new insights into the mechanisms of neurodegradation and may give structure‐based clues for rational drug design preventing amyloid associated diseases. Proteins 2010. © 2010 Wiley‐Liss, Inc.     

Cadmium stress in wheat seedlings: growth,cadmium accumulation and photosynthesis

Seedlings of wheat (Triticum aestivum L.) cultivars Jing 411, Jinmai 30 and Yangmai 10 were exposed to 0, 10, 20, 30, 40 or 50 μM of CdCl₂ in a solution culture experiment. The effects of cadmium (Cd) stress on wheat growth, leaf photon energy conversion, gas exchange, and Cd accumulation in wheat seedlings were investigated. Gas exchange was monitored at 3, 9, 24 days after treatment (DAT). Growth parameters, chlorophyll content, leaf chlorophyll fluorescence, and Cd concentration in shoot and root were measured at 24 DAT. Seedling growth, gas exchange, chlorophyll content, chlorophyll fluorescence parameters were generally depressed by Cd stress, especially under the high Cd concentrations. Cd concentration and accumulation in both shoots and roots increased with increasing external Cd concentrations. Relationships between corrected parameters of growth, photosynthesis and fluorescence and corrected Cd concentrations in shoots and roots could be explained by the regression model Y = K/(1 + exp(a + bX)). Jing 411 was found to be Cd tolerant considering parameters of chlorophyll content, photosynthesis and chlorophyll fluorescence in which less Cd translocation was from roots into shoots. The high Cd concentrations were in shoots and roots in Yangmai 10 which has been found to be a relative Cd tolerant cultivar in terms of most growth parameters.     

植物腺体的萜类代谢工程

植物所产生的气味都是从其表皮细胞特化形成的特定结构中即毛状体释放出来的。这些气味一般都是属于次生代谢过程中的单萜类化合物。产生这些气味目前认为是通过细胞质和细胞质体两种途径来合成的。而关于合成这些气味的基因调控以及基因转化工程都有了初步的研究及探索,并取得了一定的进展。     

杜仲法尼烯基焦磷酸合酶基因cDNA全长的克隆与序列分析

采用RT-PCR法,从杜仲幼嫩叶片中分离法尼烯基焦磷酸基因c DNA全长序列,克隆并对该基因全长序列进行生物信息学分析。从杜仲嫩叶中共获得两个基因分别命名为Eu FPPs1和Eu FPPs2,测序结果表明两基因开放阅读框分别为1 047 bp和1 029 bp,推测分别可以编码348个和342个氨基酸残基,在线预测表明两个蛋白序列均存在两个聚丙烯合酶位点。系统进化分析结果表明,Eu FPPs1和Eu FPPs2分别聚集于不同的分支,它们之间的进化距离为0.352,但是在亲缘关系上均与楤木和人参最近,进化距离分别为0.281、0.287,0.175、0.184。     

DMD/BMD缺失基因的检测及其表达产物的变化

目的:检测Duchenne/Becker型肌营养不良症(DMD/BMD)患者基因缺失及其表达产物--抗肌营养不良蛋白在肌细胞中的变化,探讨其与临床病情的关系.方法:应用9对引物多重PCR技术对42例DMD/BMD患者进行基因检测;并采用免疫荧光抗体染色技术对5例DMD,2例BMD肌细胞膜上抗肌营养不良蛋白的表达观察分析,以2例正常人的肌组织作为对照.结果:共发现21例外显子缺失,缺失片段长度各异,其中16例(76.2%)累及中央缺失热区,5例(23.8%)位于5'端缺失热区,尤以48号外显子缺失频率最高.5例DMD患者胞膜抗肌营养不良蛋白染色阴性,其中1例未检出基因缺失,但抗肌营养不良蛋白无表达.2例BMD患者染色弱阳性,可见间断斑片状荧光带.结论:DMD/BMD病情轻重可能与基因缺失的数量和片段大小不呈平行关系,而是与外显子的缺失类型有密切关系;基因的表达受个体差异的影响,呈高度的遗传异质性.抗肌营养不良蛋白缺乏或表达异常是造成DMD/BMD表型的病理基础,其临床后果不仅取决于缺失程度,还取决于缺失区域的功能意义.