New antimicrobial activity for the catecholamine release-inhibitory peptide from chromogranin A

Catestatin (bCGA_344–364), an endogenous peptide of bovine chromogranin A, was initially characterized for its effect on the inhibition of catecholamine release from chromaffin cells. Catestatin and its active domain (bCGA_344–358) were identified in chromaffin cells and in secretion medium. The present study identified a potent antimicrobial activity of bCGA_344–358 in the lowmicromolar range against bacteria, fungi and yeasts, without showing any haemolytic activity. Confocal laser microscopy demonstrated penetration of the rhodaminated peptide into the cell membranes of fungi and yeasts and its intracellular accumulation. Time-lapse videomicroscopy showed arrest of fungal growth upon penetration of the labelled peptide into a fungal filament. We identified several catestatin-containing fragments in the stimulated secretion medium of human polymorphonuclear neutrophils, suggesting the N-terminal sequence of catestatin (bCGA_344–358) (named cateslytin) as a novel component of innate immunity.Received 21 October 2004; received after revision 6 December 2004; accepted 7 December 2004     

Tachykinins in regulation of gastric motility and secretion

The tachykinins constitute a family of neuropeptides with a common C-terminal amino acid sequence. The best known tachykinin is substance P. Tachykinins are found in the nerve plexuses and nerve fibers in the stomach of all species examined. The circular muscle layer is densely innervated, whereas the longitudinal layer and the mucosa are less intensively innervated. Tachykinins are also found in a significant number of afferent neurons with cell bodies in the dorsal root ganglia. Release of tachykinin can be demonstrated in response to both electrical stimulation of the vagus nerves and application of capsaicin. In the stomach all three known tachykinin receptors seem to be present. Although species variations exist, NK-2 receptors are generally present on the musculature, NK-1 receptors on both neurons and muscles, and NK-3 receptors on neurons only. Tachykinins stimulate motility in all parts of the stomach, but tachykinins also appear to inhibit motility in certain situations. Also, motility initiated centrally, mediated through the vagus nerves, is influenced by tachykinins. The precise role of tachykinin in the various motor programs in the stomach is not clear. Gastric acid secretion is influenced by tachykinins in several species. Tachykinins do not seem to act as neurotransmitters directly on parietal cells, but may have a modulatory function. The importance of tachykinins for the regulation of pepsinogen and hormone secretion from the stomach remains unclear. Received 24 August 1999; received after revision 1 December 1999; accepted 3 December 1999     

作战仿真应用中实时VV&A研究

作战仿真系统是一项复杂浩大的技术工程,由于其在应用领域的重要性以及系统开发中高投入高风险的现状,使得建模与仿真(M&S)的VV&A工作变得至关重要.以具体的工程实践为依据,系统分析了作战仿真的特点,研究了在作战仿真应用阶段,一种以任务空间概念模型为驱动、可互操作、自动化、实时的VV&A方法.     

(Ag)型R-弱交换非相容映象的公共不动点定理

首先建立了一类新的Φ-压缩映象,仅利用这个压缩条件以及度量空间中自映象对的非相容性和(Ag)型R-弱交换条件,得到了一个新的公共不动点定理.这一结果去掉了对空间完备性和映象连续性的要求,并且得到了一个不连续的公共不动点.     

基于A2TPMI的电磁炉非接触式测温方案

2TPMI334是一种内部集成了专用信号处理电路以及环境温度补偿电路的多用途红外热电堆传感器，文中介绍了A2TPMI334红外热电堆传感器的性能特征，同时提出了一种利用该传感器实现电磁炉的非接触式测温的方案。     

数控直流电流源

采用高性能单片机C8051F020作为数控直流电流源的控制和测量核心,实现了电流设置、控制、输出、测量和显示.采用C8051F020内部的两路12位DAC电压输出,通过通道切换方式实现大电流和小电流的高精度指标要求;采用C8051F020内部的A/D实现负载电流的采样.通过控制继电器选择合适的主电源电压,提高了电源效率.系统还通过保存电流设置值,实现了普通旋钮仪表的位置调节记忆功能.     

农业生物技术与种业结构调整

分析了农业生物技术对种子行业结构调整的影响,当前种业面临的技术现状及其作用方式。论证了尽管中国杂交水稻与转基因作物研究居于世界前列,但由于制度约束与制度有效供给不足造成研究优势没能很好地转化为经济优势,中国种业面临巨大压力这一基本命题。     

流变压铸工艺参数对半固态A356铝合金充填性的影响

研究了半固态A356铝合金浆料的成形温度、压射比压和压射冲头速度对半固态A356铝合金流变压铸充填性的影响.实验结果表明:较高的半固态A356铝合金浆料的成形温度有利于获得良好的充填性.压射比压和压射冲头速度对半固态A356铝合金浆料充填性也具有较大的影响.在本实验条件下,压射冲头速度越大或压射比压越大,充填性越好.试片的壁厚对半固态A356铝合金浆料的充填性影响较大,试片壁厚越大,越容易充填.此外,采用低过热度浇注和弱电磁搅拌技术制备的A356铝合金浆料和流变压铸试片的组织分布很均匀,有利于获得优质的半固态压铸件.     

海水养殖真鲷肝CYP1A基因的克隆与表达

根据国外已发表野生真鲷（Pagrus major）肝CYP1A cDNA同源序列，利用反转录-聚合酶链式反应（RT-PCR）从我国海水养殖真鲷（Pagrus major）的肝脏中扩增出P4501A基因全长cDNA序列（1548bp）．用基因重组技术将P4501A cDNA克隆于pTrc-CKS载体，在大肠杆菌TOP10F＇诱导表达，将细菌总蛋白进行SDS聚丙烯酰胺凝胶电泳分析；其表达产物为89ku，获得了表达融合蛋白CKS-CYP1A．该项研究将为利用免疫学技术研究有机污染物的毒性效应机制以及探讨P450酶作为毒性效应的生物标志物奠定基础．