生物驻极体鱼鳞片的NFOM分析

利用ＮＦＯＭ系统对生物驻极体鱼鳞片进行了观测,其结果证实了我于鳞片中的骨胶朊的有序排列是其驻极特性的来源;同时又观测到了生物驻极性在生长中的结构的形态分形图像并对之讨论。     

脆性X蛋白的RNA伙伴

脆性Ｘ综合征是一种最常见的智力迟缓遗传病 .患者的Ｘ染色体上有一个单个的缺陷基因 ,尽管该缺陷基因已在十多年前鉴定出来 ,但仍不知其的发病原因 .导致该综合征的主要基因编码一个蛋白质 ,称为ＦＭＲＰ即脆性Ｘ蛋白质 ,其与ｍＲＮＡ链相结合 .神经科学家已提出理论认为当ＦＭＲＰ不能在细胞内部 ,特别是在脑细胞内部 ,适当地运送ｍＲＮＡ时 ,或不能正确调节ｍＲＮＡ制造蛋白质时 ,便会产生脆性Ｘ综合征。研究者将ＦＭＲＰ暴露于参与形成ｍＲＮＡ的多串亚基中发现ＦＭＲＰ与ｍＲＮＡ片段是紧密结合的。这种ｍＲＮＡ片段形成奇特的立方体结…     

林其谁教授当选FAOBMB主席

中国科学院生物化学与细胞生物学研究所研究员、原中国科学院上海生物化学研究所所长、原中国生物化学与分子生物学会第四届理事长林其谁教授 ,最近当选亚洲大洋洲生物化学家与分子生物学家联合会主席。亚洲与大洋洲生物化学与分子生物学家联合会 (ＦｅｄｅｒａｔｉｏｎｏｆＡｓｉａｎａｎｄＯｃｅａｎｉａｎＢｉｏｃｈｅｍｉｓｔｓａｎｄＭｏｌｅｃｕ ｌａｒＢｉｏｌｏｇｉｓｔＩｎｃ . ,ＦＡＯＢＭＢ)是ＩＵＢＭＢ下的四个区域性学会之一 [其它三个区域性学会是ＰＡＢＭＢ(泛美 ) ,ＦＥＢＳ(欧洲 ) ,ＦＡＢＳ(非洲 ) ]。目前ＦＡＯＢＭＢ…     

用高效液相色谱法测定鱼样中的维生素D3和E

用高效液相色谱法测定鱼样中的维生素Ｄ＿３和Ｅ徐立红,陈专,徐盈,张甬元（中国科学院水生生物研究所,武汉４３００７２）ＭＥＡＳＵＲＥＭＥＮＴＯＦＶＩＴＡＭＩＮＤ＿３ＡＮＤＶＩＴＡＭＩＮＥＯＦＦＩＳＨＳＡＭＰＬＥＳＢＹＨＰＬＣ￥ＸｕＬｉｈｏｎｇ,Ｃｈｅｎ...     

鲤体长与体内元素富集数学模型

鲤体长与体内元素富集数学模型王继忠,徐小清（中国科学院水生生物研究所,武汉４３００７２）ＡＭＡＴＨＥＭＡＴＩＸＡＬＭＯＤＥＬＦＯＲＢＯＤＹＬＥＮＧＴＨＡＮＤＥＬＥＭＥＮＴＣＯＮＴＥＮＴＩＮＴＨＥＢＯＤＹＯＦＣＡＲＰ￥ＷａｎｇＪｉｚｈｏｎｇａｎｄＸｕＸ...     

阿霉素铁(Ⅲ)配合物与DNA结合作用的研究

应用吸收光谱法研究了阿霉素铁（Ⅲ）［ＡＤＭ·Ｆｅ（Ⅲ）］与ＤＮＡ的结合作用,结果表明ＡＤＭ·Ｆｅ（Ⅲ）作为一个整体嵌入ＤＮＡ碱基之间形成ＡＤＭ·Ｆｅ（Ⅲ）·ＤＮＡ三元复合物。应用荧光淬灭法得到了不同Ｎａ＋浓度下ＡＤＭ及ＡＤＭ·Ｆｅ（Ⅲ）与ＤＮＡ结合作用的结合常数（Ｋ）、结合位点距离（ｎ）及标准自由能（ΔＧ）,并根据多聚电解质理论将ΔＧ分解为电荷作用部分（ΔＧｐｅ）及非电荷作用部分（ΔＧｔ）。结果表明ＡＤＭ·Ｆｅ（Ⅲ）中铁离子直接参与了与ＤＮＡ的作用,ＡＤＭ·Ｆｅ（Ⅲ）较ＡＤＭ更易与ＤＮＡ结合,且结合更为紧密     

中国鲌亚科－新属（鲤形目：鲤科）

中国鲌亚科－新属（鲤形目：鲤科）罗云林（中国科学院水生物研究所,武汉４３００７２）关键词新属,亚科ＡＮＥＷＧＥＮＲＵＯＦＣＵＬＴＲＩＮＡＥＦＲＯＭＣＨＩＮＡ（ＣＹＰＲＩＮＩＦＯＲＭＥＳ：ＣＹＰＲＩＮＩＤＡＥ）￥ＬｕｏＹｕｎｌｉｎ（ＩｎｓｔｕｔｅｏｆＨ...     

激光参数对黑曲霉生物效应的影响

激光参数对黑曲霉生物效应的影响陈荣,谢树森,黄俊民（福建师范大学激光所福州,５３０００７）吴松刚,陈哲超,谢必峰（福建师范大学微生物工程所）关键词激光;黑曲霉;生物效应ＴＨＥＥＦＦＥＣＴＳＯＦＬＡＳＥＲＰＡＳＡＭＥＴＥＲＯＮＡＳＰＥＲＧＩＬＬＩＣＮＩ...     

用电荷积分法测定生物驻极体的极化电荷存储

以驻极体（猪骨）为研究对象,用电荷积分法测定在一定湿度和温度下它的极化电荷存储（热释电常数）。结果表明本方法是测定生物驻极体极化电荷存储的有效的方法。文中讨论了极化电荷存储受温、湿度影响效应并分析了自由水、结合水对其的贡献区别。     

黄腐酸拌种对春小麦产量和水分利用效率的影响

在大田研究了黄腐酸拌种对春小麦产量形成和水分利用效率的影响。实验设４个处理：对照（ＣＫ）,播种前种子不处理;ＦＡ处理：播种前用ＦＡ拌种;ＷＭ处理：浇３０ｍｍ底墒水,覆膜;处理ＷＭＦＡ：浇３０ｍｍ底墒水,覆膜,播种前用ＦＡ拌种。２个覆膜处理均在播种后６２ｄ揭膜。同ＣＫ相比,ＦＡ拌种后,根系生长良好,吸收利用了更多的土壤水分,增加了穗重、单穗籽粒重和收获指数,产量和水分利用效率均显著提高。ＷＭ和ＷＭＦ     

Ultrastructural studies on the collagen of the marine sponge Chondrosia reniformis Nardo

The ultrastructure of isolated fibrils of Chondrosia reniformis sponge collagen was investigated by collecting characteristic data, such as fibril thickness, width, D-band periodicity, and height modulation, using atomic force microscopy (AFM) and transmission electron microscopy (TEM). Therefore an adapted pre-processing of the insoluble collagen into homogeneous suspensions using neutral buffer solutions was essential, and several purification steps have been developed. Fourier transform infrared reflection-absorption spectroscopy (FT-IRAS) of the purified sponge collagen showed remarkable analogy of peak positions and intensities with the spectra of fibrillar calf skin type I collagen, despite the diverse phylogenetic and evolutionary origin. The sponge collagen's morphology is compared with that of other fibrillar collagens, and the typical banding of the separated single fibrils is discussed by comparison of topographical data obtained using AFM and corresponding TEM investigations using common staining methods. As the TEM images of the negatively stained fibrils showed alternating dark and light bands, AFM revealed a characteristic periodicity of protrusions (overlap zones) followed by two equal interband regions (gap zones). AFM and TEM results were correlated and multiperiodicity in Chondrosia collagen's banding is demonstrated. The periodic dark bands observed in TEM images correspond directly to the periodic protrusions seen by AFM. As a result, we provide an improved, updated model of the collagen's structure and organization.     

Probing the effect of glycosaminoglycan depletion on integrin interactions with collagen I fibrils in the native extracellular matrix environment

Fibrillar collagen–integrin interactions in the extracellular matrix (ECM) regulate a multitude of cellular processes and cell signalling. Collagen I fibrils serve as the molecular scaffolding for connective tissues throughout the human body and are the most abundant protein building blocks in the ECM. The ECM environment is diverse, made up of several ECM proteins, enzymes, and proteoglycans. In particular, glycosaminoglycans (GAGs), anionic polysaccharides that decorate proteoglycans, become depleted in the ECM with natural aging and their mis-regulation has been linked to cancers and other diseases. The impact of GAG depletion in the ECM environment on collagen I protein interactions and on mechanical properties is not well understood. Here, we integrate ELISA protein binding assays with liquid high-resolution atomic force microscopy (AFM) to assess the effects of GAG depletion on the interaction of collagen I fibrils with the integrin α2I domain using separate rat tails. ELISA binding assays demonstrate that α2I preferentially binds to GAG-depleted collagen I fibrils in comparison to native fibrils. By amplitude modulated AFM in air and in solution, we find that GAG-depleted collagen I fibrils retain structural features of the native fibrils, including their characteristic D-banding pattern, a key structural motif. AFM fast force mapping in solution shows that GAG depletion reduces the stiffness of individual fibrils, lowering the indentation modulus by half compared to native fibrils. Together these results shed new light on how GAGs influence collagen I fibril–integrin interactions and may aid in strategies to treat diseases that result from GAG mis-regulation.     

原子力显微镜研究UV-B对I型胶原结构的影响

利用原子力显微镜(AFM)成像技术观察胶原蛋白溶液在UV-B照射前后形态的变化,发现UV-B引起胶原纤维交联度的增加,当交联达一定程度后,照射时间的增加对交联度增加的影响不明显。AFM作为一种高分辨的表面分析仪器,为分子生物学领域的研究提供了一种新的手段。是探讨胶原光作用机理直观、有效的方法。     

Structural investigations on native collagen type I fibrils using AFM

This study was carried out to determine the elastic properties of single collagen type I fibrils with the use of atomic force microscopy (AFM). Native collagen fibrils were formed by self-assembly in vitro characterized with the AFM. To confirm the inner assembly of the collagen fibrils, the AFM was used as a microdissection tool. Native collagen type I fibrils were dissected and the inner core uncovered. To determine the elastic properties of collagen fibrils the tip of the AFM was used as a nanoindentor by recording force-displacement curves. Measurements were done on the outer shell and in the core of the fibril. The structural investigations revealed the banding of the shell also in the core of native collagen fibrils. Nanoindentation experiments showed the same Young's modulus on the shell as well as in the core of the investigated native collagen fibrils. In addition, the measurements indicate a higher adhesion in the core of the collagen fibrils compared to the shell.     

Observing growth steps of collagen self-assembly by time-lapse high-resolution atomic force microscopy

Insights into molecular mechanisms of collagen assembly are important for understanding countless biological processes and at the same time a prerequisite for many biotechnological and medical applications. In this work, the self-assembly of collagen type I molecules into fibrils could be directly observed using time-lapse atomic force microscopy (AFM). The smallest isolated fibrillar structures initiating fibril growth showed a thickness of approximately 1.5 nm corresponding to that of a single collagen molecule. Fibrils assembled in vitro established an axial D-periodicity of approximately 67 nm such as typically observed for in vivo assembled collagen fibrils from tendon. At given collagen concentrations of the buffer solution the fibrils showed constant lateral and longitudinal growth rates. Single fibrils continuously grew and fused with each other until the supporting surface was completely covered by a nanoscopically well-defined collagen matrix. Their thickness of approximately 3 nm suggests that the fibrils were build from laterally assembled collagen microfibrils. Laterally the fibrils grew in steps of approximately 4 nm, indicating microfibril formation and incorporation. Thus, we suggest collagen fibrils assembling in a two-step process. In a first step, collagen molecules assemble with each other. In the second step, these molecules then rearrange into microfibrils which form the building blocks of collagen fibrils. High-resolution AFM topographs revealed substructural details of the D-band architecture of the fibrils forming the collagen matrix. These substructures correlated well with those revealed from positively stained collagen fibers imaged by transmission electron microscopy.     

Atomic force microscopy-based detection of binding and cleavage site of matrix metalloproteinase on individual type II collagen helices

Type II tropocollagen molecules were reacted with matrix metalloproteinase 8 (MMP-8) and the binding sites as well as the cleavage site of MMP-8 were detected on individual molecules using atomic force microscopy (AFM). Approximately 300-nm-long coiled-coil tropocollagen molecules were straightened and immobilized on an atomically flat surface for detection by AFM. The direct visualization of individual collagen molecules revealed heterogeneous characteristics of MMP-8:collagen complexes. We observed that there existed multiple MMP-8 nonspecific binding sites on the collagen molecules, but cleavage always took place at a unique site. When collagen molecules, straightened and immobilized on the surface, were reacted with MMP-8, a site of cleavage appeared as a gap in stretched molecules. This is the first report to visually show direct collagenase:collagen interactions using AFM. The described AFM-based analysis has potential as a protein analysis tool for understanding a complex mechanism of enzyme:substrate interactions.     

Imaging real-time proteolysis of single collagen I molecules with an atomic force microscope.

The dynamic process of synthesis and degradation of extracellular matrix molecules, including various collagens, is important in normal physiological functions and pathological conditions. Existing models of collagen enzymatic degradation reactions are derived from bulk biochemical assays. In this study, we have imaged in real-time individual collagen I molecules and their proteolysis by Clostridium histolyticum collagenases in phosphate-buffered saline (PBS) with atomic force microscopy (AFM). We have also imaged the likely binding and unbinding of collagenase molecules to single triple-helical collagen I molecules and subsequent proteolysis of subsets of the collagen molecules. The proteolysis of collagen molecules was inhibited by reduced calcium and acidification. Results from AFM study of collagen proteolysis are consistent with SDS-PAGE biochemical assays. The real-time proteolysis of single collagen I molecules followed simple Michaelis-Menton kinetics previously derived from bulk biochemical assays. This is the first report of imaging real-time proteolysis of single macromolecules and its inhibition on a molecular scale. A strong correspondence between the kinetics of proteolysis of single collagen molecules and the kinetics of proteolysis derived from bulk biochemical assays will have a wide applicability in examining real-time enzymatic reactions and their regulation at single molecule structural level. Such real-time study of single molecule proteolysis could provide a better understanding of the interactions between proteases and target proteins as well as proteases and protease inhibitors.     

Atomic force microscopy and FT-IR spectroscopy investigations of human heart valves

Human aortic, mitral, tricuspid and pulmonary heart valves were investigated by the contact mode atomic force microscopy (AFM) in air, and using FT-IR spectroscopy in the frequency range 950-4000 cm(-1). Heart valves were collected post mortem from 65-78 years old patients who died from non-cardiac diseases. All of the examined valves showed considerable heterogeneity in the surface topography of collagen fibrils as well as in their organization on the tissue surface. The AFM images revealed areas with significantly different spatial organization of the collagen fibril bundles. We observed zones with multidirectional, stacked collagen fibrils as well as areas of thin fibrils packed regularly, densely and "in phase". The majority of the collagen fibrils reproduced the typical transverse D-banding pattern, with the band interval varying in rather wide range of 70-90 nm. Using AFM imaging, objects that correspond to some pathological states of heart valves at their early stages, i.e. some forms of mineral deposits, were observed. The FT-IR spectra allowed us to recognize main components, i.e. collagen and elastin, in di.erent layers (ventricularis, fibrosa) of the valve leaflets as well as they gave also support for the presence of mineral deposits on the valve surface. The presented results showed, that the AFM imaging and FT-IR spectroscopy can be applied as a complementary methods for structural characterization of heart valves at the molecular and supramolecular levels.     

Investigating the ultrastructure of fibrous long spacing collagen by parallel atomic force and transmission electron microscopy

The ultrastructure of fibrous long spacing (FLS) collagen fibrils has been investigated by performing both atomic force microscopy (AFM) and transmission electron microscopy (TEM) on exactly the same area of FLS collagen fibril samples. These FLS collagen fibrils were formed in vitro from type I collagen and alpha1-acid glycoprotein (AAG) solutions. On the basis of the correlated AFM and TEM images obtained before and after negative staining, the periodic dark bands observed in TEM images along the longitudinal axis of the FLS collagen fibril correspond directly to periodic protrusions seen by AFM. This observation is in agreement with the original surmise made by Gross, Highberger, and Schmitt (Gross J, Highberger JH, Schmitt FO, Proc Natl Acad Sci USA 1954;40:679-688) that the major repeating dark bands of FLS collagen fibrils observed under TEM are thick relative to the interband region. Although these results do not refute the idea of negative stain penetration into gap regions proposed by Hodge and Petruska (Petruska JA, Hodge AJ. Aspects of protein structure. Ramachandran GN, editor. New York: Academic Press; 1963. p. 289-300), there is no need to invoke the presence of gap regions to explain the periodic dark bands observed in TEM images of FLS collagen fibrils.