用N-(3-P)NEM标记毛发角蛋白研究毛发中低硫蛋白和高硫蛋白的状态

本文用一种特异性标记蛋白质巯基的N-(3-P)NEM为荧光探针标记毛发角蛋白,经SDS-PAGE后,通过荧光薄层扫描确定N-(3-P)NEM与含巯基蛋白结合的部位。结果表明,毛发角蛋白中的低硫蛋白分子量在45,000～63,000范围,约占总蛋白量的49.6％～68.2％;高硫蛋白分子量在4,000～20,000范围,约占总蛋白量的18.9％～36.2％。除低硫和高硫蛋白以外,毛发角蛋白中还可能存在一种极低硫蛋白,分子量位于22,000～32,000范围。对人与5种动物的毛发角蛋白组分进行比较,证实人与动物的毛发角蛋白的主要差异在高硫蛋白,不同种属的动物毛发角蛋白中低硫蛋白和高硫蛋白的含量也不相同。作者认为毛发角蛋白中含巯基蛋白的差异可为动物分类学和法医学在进行毛发比较鉴别方面提供新的重要信息。     

纤维的形变和断裂——Ⅰ.拉伸角蛋白纤维形变和断裂的动态研究

作者在扫描电子显微镜样品室中拉伸角蛋白纤维,观察纤维形变和断裂的过程并摄取其照片。采用低加速电压观察和适当的样品准备技术,避免了纤维在拉伸过程中出现荷电现象。该现象是非导电材料作动态观察的主要困难。从所观察到的纤维形变和断裂形态和高聚物断裂理论讨论了角蛋白纤维的形变和断裂机理。结论如下:角蛋白纤维伸长和断裂过程中出现银纹样形态,但其断裂为脆性方式;该类纤维的拉伸断裂起始于角质细胞的内、外角质层;角质与角质和角质与皮质细胞间的物质是角蛋白纤维的力学薄弱区。     

几种“奇异动物”毛发的血型物质及角蛋白等电聚焦谱分析

本文用聚丙烯酰胺凝胶等电聚焦(PAGIEF)和解离试验法对“奇异动物”毛发的血型物质和角蛋白组分进行了分析结果表明,二份分别收集于贵州黎平县和四川巫溪县的“奇异动物”毛发具有与某些灵长类动物毛发类似的A和AB型血型物质.二者毛发角蛋白组分的PAGIEF谱型非常相近,但与黑猩猩,长臂猿,阿拉伯狒狒,狗熊,山羊和豚鼠的毛发有差异,与人头发也不一样.作者认为,二份“奇异动物”毛发属于同一种属的动物.它们可能属于与灵长类动物有一定亲缘关系,但又有差异的一类未知灵长类动物.有关这种“奇异动物”种属关系的确切认定,尚有待进一步研究.     

An immunohistochemical study of the clearance of apoptotic cellular fragments

We investigated the distribution and fate of apoptotic bodies during human development and in the adult, using an antibody (M30) that recognizes a neo-epitope formed early in the apoptotic cascade by caspase cleavage of cytokeratin 18. In the fetus, we found extensive accumulation of M30-positive, non-phagocytosed fragments in the red pulp of the spleen, subcutaneous and submucosal vessels, the interstitium of the lung, and the glomerular mesangium of the kidneys. In the liver, M30-immunoreactive fragments were found inside macrophages in the sinusoids. The number of these fragments and the intensity of the immunostaining increased with the gestational age of the fetus. In the adult, M30-positive fragments were barely detectable in normal tissues. However, many pathological situations, including both chronic degenerative processes and metastatic cancer, were associated with accumulation of M30-positive fragments in the red pulp of the spleen. In the liver and kidney, no fragments could be detected. Remarkably, 13 of the 16 patients with metastasized cancer showed pronounced accumulation of M30-positive fragments containing hematoxylin-reactive material in the red pulp of the spleen. In the non-cancerous cases, such DNA-containing fragments were only seen in 9 of 94 cases. The results show that when apoptotic activity is high, as during development in the fetus or during metastasis and other pathological processes in the adult, the phagocytic clearance of apoptotic bodies can be overloaded. These apoptotic fragments then accumulate in the spleen. The visual detection of apoptotic fragments is concluded to reflect increased cell turnover. Received 1 July 2002; accepted 1 July 2002     

NF-L and NF-M are expressed in epithelial cells and coassemble with keratin or vimentin

Neurofilaments (NFs) and cytokeratins are both heteropolymers, which assemble into intermediate filaments (IFs) only when other proper IF subunit proteins are expressed simultaneously. To study the assembly property of NFs, we constructed two recombinant adenovirus which could express NF-L or NF-M, fused with green fluorescent protein (GFP) respectively. Then they were introduced into vero cells, and expressed fusion protein. Double labels of GFP fluorescence and immunofluorescence staining indicated that NF-L-GFP or GFP-NF-M not only coassembled with endogenous vimentins, but also coassembled with keratins into a cytoplasmic network of filaments.     

蛋白质分子α螺旋结构的发现

笔者具体介绍了蛋白质分子α螺旋结构的发现过程。鲍林是怎样在了解蛋白质组成和X射线研究的实验成果的基础上,从结构化学的角度认识到在蛋白质中氢键的性质和作用,揭示了肽基的刚性平面性质,从而发现了蛋白质分子的α螺旋结构的。     

氧化棉纤维经角蛋白溶液处理后的结构及性能研究

采用氢氧化钠和双氧水溶解羊毛制得可溶性角蛋白溶液,再对经高碘酸钠选择性氧化的棉纤维进行处理.研究了氧化棉纤维经角蛋白溶液处理后的结构和力学性能.结果表明,氧化棉纤维经角蛋白溶液处理后产生增重,同时在纤维表面吸附成膜,红外光谱表明角蛋白与氧化棉纤维之间形成共价结合,且氧化棉纤维经角蛋白溶液处理后的力学性能基本不变.     

人发角蛋白桥接周围神经缺损的功能评价

目的通过在神经再生室内植入人发角蛋白,观察神经的功能恢复情况,为桥接周围神经缺损寻求新的替代材料。方法将18只新西兰兔的左侧坐骨神经切断,造成lOmm缺损,实验组用人发角蛋白桥接,对照组用空硅胶管桥接,术后检测坐骨神经功能指数、电生理、腓肠肌湿重,观察神经功能的恢复情况。结果8周时,试验组坐骨神经功能指数值优于对照组（P〈0．01）;12周时,试验组坐骨神经功能指数、潜伏期和神经传导速度及波幅明显好于对照组（P〈0．01）。结论人发角蛋白能促进兔坐骨神经功能的恢复是桥接周围神经缺损的理想材料。     

羊毛及其角朊膜显微傅立叶红外光谱对比分析

运用傅立叶变换红外光谱（FTIR）技术对羊毛、由该羊毛溶解制成的角朊蛋白膜、再生羊毛和腈纶进行对比分析。通过显微FTIR光谱的特征峰讨论，比较了此类试样在组成和结构上的差别。     

Specific degradation of keratin in Xenopus laevis egg extracts undergoing apoptosis

Cytochrome c activates apoptosis specific protease XCPP32 when being added to Xenopus laevis egg extracts, and induces apoptosis in this cell-free system. During apoptosis, cyto-skeleton proteins in egg extracts are degraded. Western blot assay indicates that 42-ku acidic keratin in egg extracts has been degraded by XCPP32. The degradation of 42-ku keratin may be crucial in apoptosis.