PACAP-38 and PAC1 Receptor Alterations in Plasma and Cardiac Tissue Samples of Heart Failure Patients

Pituitary adenylate cyclase activating polypeptide-38 (PACAP-38) is a multifunctional neuropeptide, which may play a role in cardioprotection. However, little is known about the presence of PACAP-38 in heart failure (HF) patients. The aim of our study was to measure the alterations of PACAP-38 like immunoreactivity (LI) in acute (n = 13) and chronic HF (n = 33) and to examine potential correlations between PACAP-38 and HF predictors (cytokines, NT-proBNP). Tissue PACAP-38 LI and PAC1 receptor levels were also investigated in heart tissue samples of patients with HF. Significantly higher plasma PACAP-38 LI was detected in patients with acute HF, while in chronic HF patients, a lower level of immunoreactivity was observed compared to healthy controls (n = 13). Strong negative correlation was identified between plasma PACAP-38 and NT-proBNP levels in chronic HF, as opposed to the positive connection seen in the acute HF group. Plasma IL-1 β, IL-2 and IL-4 levels were significantly lower in chronic HF, and IL-10 was significantly higher in patients with acute HF. PACAP-38 levels of myocardial tissues were lower in all end-stage HF patients and lower PAC1 receptor levels were detected in the primary dilated cardiomyopathy group compared to the controls. We conclude that PACAP-38 and PAC1 expression correlates with some biomarkers of acute and chronic HF; therefore, further studies are necessary to explore whether PACAP could be a suitable prognostic biomarker in HF patients.     

Effect of Acute Sprint Exercise on Myokines and Food Intake Hormones in Young Healthy Men

Physical exercise is known to influence hormonal mediators of appetite, but the effect of short-term maximal intensity exercise on plasma levels of appetite hormones and cytokines has been little studied. We investigated the effect of a 30 s Wingate Test, followed by a postprandial period, on appetite sensations, food intake, and appetite hormones. Twenty-six physically active young males rated their subjective feelings of hunger, prospective food consumption, and fatigue on visual analogue scales at baseline, after exercise was completed, and during the postprandial period. Blood samples were obtained for the measurement of nesfatin-1, ghrelin, leptin, insulin, pancreatic polypeptide (PP), human growth factor (hGH) and cytokine interleukin-6 (IL-6), irisin and plasma lactate concentrations, at 30 min before exercise, immediately (210 s) after exercise, and 30 min following a meal and at corresponding times in control sedentary males without ad libitum meal intake, respectively. Appetite perceptions and food intake were decreased in response to exercise. Plasma levels of irisin, IL-6, lactate, nesfatin-1 and ghrelin was increased after exercise and then it was returned to postprandial/control period in both groups. A significant rise in plasma insulin, hGH and PP levels after exercise was observed while meal intake potentiated this response. In conclusion, an acute short-term fatiguing exercise can transiently suppress hunger sensations and food intake in humans. We postulate that this physiological response involves exercise-induced alterations in plasma hormones and the release of myokines such as irisin and IL-6, and supports the notion of existence of the skeletal muscle–brain–gut axis. Nevertheless, the detailed relationship between acute exercise releasing myokines, appetite sensations and impairment of this axis leading to several diseases should be further examined.     

消化对益生菌干酪抗氧化活性的影响

为探究益生菌干酪经模拟胃肠道消化后抗氧化活性的变化,本研究以1,1-二苯基-2-三硝基苯肼 （1,1-diphenyl-2-picrylhydrazyl,DPPH）自由基清除率、还原力和2,2’-联氮-二（3-乙基-苯并噻唑-6-磺酸）二铵盐 （2,2’-azino-bis(3-ethylbenzthiozoline-6)-sulphonic acid,ABTS）自由基清除率为评价指标,同时研究添加双歧杆菌 （Bifidobacterium bifidum）07-300B、嗜酸乳杆菌（Lactobacillus acidophilus）1.0357的契达干酪消化前后的益生菌 活菌数及产生多肽的变化,从而明确消化对其抗氧化活性的影响。结果表明：干酪经消化后抗氧化活性显著增加 （P＜0.05）,其中添加两种益生菌的干酪抗氧化指标显著高于其他组（P＜0.05）,DPPH自由基清除率、还原 力、ABTS＋·清除率分别为（82.76±3.19）%、0.828±0.021、（44.84±1.36）%,较消化前分别增加了71.42%、 62.35%和51.69%;同时多肽质量浓度也显著增加（P＜0.05）,达到（2.80±0.02）mg/mL,较消化前增加了 39.30%,其中分子质量小于3 kDa的多肽抗氧化活性最高;而益生菌活菌数显著降低（P＜0.05）,相对于消化前降 低了16.93%。由此可知,模拟胃肠道消化后干酪抗氧化活性的提高主要与消化后产生具有抗氧化活性的小分子多肽 有关。     

Comparison of systematic search and database methods for constructing segments of protein structure

Two principal methods of determining the conformation of shortpieces of polypeptide backbone in proteins have been developed:using a database of known structures and systematicallygeneratingall conformations. In this paper, we compare the effectivenessof these two techniques. The completeness of the database forsegments of different lengths is examined and it is found tocontain most conformations for segments seven residues long,but to deteriorate rapidly for longer regions. When the databasesegment is to be incorporated into the rest of a structure,at least seven residues are required to build four new residues,because of the need to positionthe segment relative to the restof the structure.It is found that such positioning using flankingresidues results in large errors in the inserted region. Weconclude that the database method is currently not effectivefor comparative modeling, even for short segments. The systematicsearchprocedure is found to generate almost all structures of shortsegments found in proteinsIn contrast to the database method,low root mean square error structures are obtained for a setof trial segments embedded in the rest of a protein structure.Thus, it should be considered the method of choice.     

液晶多肽及其应用研究

基于国内外最新研究文献,系统论述了近年来液晶多肽的大分子链结构、液晶性能及应用前景等方面的研究进展。指出液晶多肽在一定条件下将出现各向同性态到各向异性态的可逆转变,伴随着大分子链从线圈状到螺旋状的可逆转变。聚[γ－苄基－L－谷氨酸酯]有序度参数可达0.875。二次谐波的产生证明了有些液晶多肽呈现奇异的胆甾相结构,其胆甾相由极性向列型片晶组成,且分子偶极矩和长轴方向平行。多肽既可显示溶致液晶性又可显示热致液晶性,其液晶相多为胆甾型,有时呈向列型。外加场如取向场及电场对多肽的液晶性也会产生强烈影响。液晶多肽可加工成液晶态水凝胶、纤维和薄膜等,可望用作全息照相材料、光学元件、彩色滤色器以及溶致液晶电池等。     

含偶氮苯单元光响应多肽的研究进展

综述了含偶氮苯光色性单元的多肽光响应效应，主要包括光诱导的无规线团与右手α-螺旋之间的转变；左、右手-α-螺旋的反转；光激发的聚集-解聚过程以及由多肽形成的单层膜光力学效应。这些效应表明光响应多肽是一类很有前景的光响应化合物，可作为设计光调节传感器等光响应装置的合适材料。     

水蛭多肽对大鼠脑缺血-再灌注损伤的保护作用及其机制

目的：探讨水蛭多肽提取物对大鼠脑缺血-再灌注损伤的保护作用及其作用机制。方法采用线栓法制备大鼠脑缺血-再灌注损伤模型,制模成功后按随机数字表法分为4组：模型组（A 组,n＝6）、水蛭多肽低剂量组（5 mg· kg－1,B 组,n＝7）、水蛭多肽高剂量组（10 mg·kg－1,C 组,n＝8）及灯盏花素注射液阳性对照组（5 mg·kg－1,D 组,n＝7）;另取大鼠7只制作假手术组（E 组）。5组均尾静脉注射给药,每日1次,连续7 d;B、C、D 组给予相对应药物,A、E组给予等体积生理盐水。采用称重法测定大鼠体质量、进食量,TTC 染色法测定脑梗死体积,伊文思蓝法测定血-脑屏障功能。结果与 A 组比较,B、C、D 组体质量降低程度、神经功能评分、脑梗死体积均显著减小,进食量显著增加,血-脑屏障功能显著改善（P ＜0．05或 P ＜0．01）。结论水蛭多肽对大鼠脑缺血-再灌注损伤具有显著的保护作用,其保护机制与其对血-脑屏障损伤的改善有关。     

Enhancement reactivity of Bombyx mori silk fibroins via genipin-mediated grafting of a tyrosine-rich polypeptide

Bombyx mori silk fibroin has potential applications in the biomedical field owing to its satisfactory biocompatibility. In the present work, a tyrosine-rich polypeptide (P) with the sequence of GKGYGGYGK was grafted onto fibroin molecules using a natural cross-linking agent of genipin (GP), aiming at improving the reactivity of the fibroin-based materials. Incubation of the polypeptide-grafted fibroin membrane was subsequently carried out, with a mushroom tyrosinase (MT) and a model functional macromolecule of ε-poly-l-lysine (ε-PL). The changes in the structure and composition of the silk fibroin before and after polypeptide grafting were examined by means of size exclusion chromatography and amino acid analysis. The results indicated that the polypeptide was covalently bonded to fibroin chains and evidently promoted the succeeding enzymatic coupling of ε-PL with fibroins, resulting in a higher content of ε-PL compared to the control. The obtained antibacterial activities against S. aureus and E. coli for the fibroin membrane treated with GP/P and MT/ε-PL was more satisfactory than others. Cytotoxicity testing reveals that polypeptide grafting did less impact on the biocompatibility of silk fibroins. The present work provides a novel method to improve the reactivity of silk fibroins and it can be utilized for bio-functionalization of silk fibroin.     

胶原多肽钙的制备及小鼠应用试验

以制革厂准备工段的边角废料为原料,经酶两步法水解制备出高纯度的胶原多肽,选择合适的钙源使之和胶原多肽复合,制备出易于人体吸收、胶原与钙双补的新型补钙制剂,经小鼠应用试验证明效果良好。