共查询到20条相似文献，搜索用时 131 毫秒
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神经网络在蛋白质结构预测中的应用 总被引：2，自引：0，他引：2
蛋白质结构预测在生物信息学研究中占有重要地位.此文对神经网络在蛋白质结构预测中的应用作了评述。首先,简要地介绍了人工神经网络,然后对近年来用神经网络算法解决蛋白质结构预测的研究作了回顾,并分析了算法的效果和特点。最后,展望了用神经网络算法解决蛋白质结构预测问题的前景。 相似文献
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研究了细胞内存在的分子伴侣、蛋白质聚集和大分子拥挤环境对蛋白质折叠的影响.首先,发现分子伴侣GroEL与底物蛋白的结合有 半位 "和 全位"两种模式,它是由底物蛋白的分子形状、分子大小以及与GroEL的相互作用性质决定的.接着,发现两种不同的蛋白质一起复性时相互不干扰,提示细胞内蛋白质折叠可能不受其他蛋白聚集的影响;后又发现α 乳清蛋白的前熔球态不仅是分子伴侣也是蛋白质聚集体的作用对象.最后,研究大分子拥挤环境对蛋白质折叠热力学和动力学的影响,揭示了这种影响的复杂性和多样性. 相似文献
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家蚕从基因组到蛋白质组的研究 总被引：1，自引：0，他引：1
家蚕基因组计划实施以来,用DNA限制性片段长度多态性(RFLP)、随机扩增片段多态性(RAPD)、扩增片段长度多态性(AFLP)、微卫星序列长度多态性(SSR)等多种分子标记技术进行了家蚕基因组多态性分析,构建了家蚕分子连锁图谱;开展了家蚕基因组序列测定和功能基因的研究.在后基因组时代,蛋白质组研究是基因功能研究的重要内容.家蚕蛋白质组研究虽然刚刚起步,但已确立了家蚕蛋白质样品制备方法,利用双向电泳技术和图像分析技术进行了家蚕功能蛋白质研究.该文对家蚕基因组和蛋白质组的研究进展进行了综述. 相似文献
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蛋白质结构预测在生物信息学研究中占有重要地位。对神经网络在蛋白质结构预测中的应用作了评述。首先,简要地介绍了人工神经网络,然后对近年来用神经网络算法解决蛋白质结构预测的研究作了回顾,并分析了算法的效果和特点。最后,展望了用神经网络算法解决蛋白质结构预测问题的前景。 相似文献
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高压对食品中蛋白质结构的影响 总被引：1，自引：0，他引：1
由于高压技术能在不影响食品风味和营养的前提下延长制品的贮存期,改善产品的组织结构,所以,近十几年来,高压技术逐渐成为食品工作者研究的热点。高压对蛋白质的作用是高压技术在食品中应用的基础,文章概述了高压对蛋白质的结构、凝胶和溶胶的转化等的影响。 相似文献
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生物信息学是在生命科学研究中独具活力的新兴前沿学科之一。它利用计算机硬件、软件和计算机网络,采用信息学、计算机科学和数学的手段,主要研究蛋白质、核酸等生物大分子数据。本文着重介绍了两种智能化算法,分别讨论了人工神经网络方法在蛋白质二级结构预测中的应用及遗传算法在蛋白质二维晶格中的应用。 相似文献
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自身免疫性疾病的检测诊断与发病机制非常复杂,蛋白质芯片技术成为研究以自身抗体为特征的自身免疫性疾病的快速、有效的工具,在定量检测和新标志物的发现中有着广泛的应用前景。蛋白质芯片是继基因芯片之后发展起来的一种后基因组研究技术,能够对样品蛋白进行高通量、高灵敏度、高特异性的分析,是蛋白质组学研究中强有力的工具。本文就蛋白质芯片及其在自身免疫系统疾病诊断与检测中的应用作一综述。 相似文献
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Guillaume Mottet Karla Perez-Toralla Ezgi Tulukcuoglu Francois-Clement Bidard Jean-Yves Pierga Irena Draskovic Arturo Londono-Vallejo Stephanie Descroix Laurent Malaquin Jean Louis Viovy 《Biomicrofluidics》2014,8(2)
We present a low cost microfluidic chip integrating 3D micro-chambers for the capture and the
analysis of cells. This device has a simple design and a small footprint. It allows the
implementation of standard biological protocols in a chip format with low volume consumption. The
manufacturing process relies on hot-embossing of cyclo olefin copolymer, allowing the development of
a low cost and robust device. A 3D design of microchannels was used to induce high flow velocity
contrasts in the device and provide a selective immobilization. In narrow distribution channels, the
liquid velocity induces a shear stress that overcomes adhesion forces and prevents cell
immobilization or clogging. In large 3D chambers, the liquid velocity drops down below the threshold
for cell attachment. The devices can be operated in a large range of input pressures and can even be
handled manually using simple syringe or micropipette. Even at high flow injection rates, the 3D
structures protect the captured cell from shear stress. To validate the performances of our device,
we implemented immuno-fluorescence labeling and Fluorescence in Situ Hybridization
(FISH) analysis on cancer cell lines and on a patient pleural effusion sample. FISH is a Food and
Drug Administration approved cancer diagnostic technique that provides quantitative information
about gene and chromosome aberration at the single cell level. It is usually considered as a long
and fastidious test in medical diagnosis. This process can be easily implanted in our platform, and
high resolution fluorescence imaging can be performed with reduced time and computer intensiveness.
These results demonstrate the potential of this chip as a low cost, robust, and versatile tool
adapted to complex and demanding protocols for medical diagnosis. 相似文献
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We demonstrate a highly integrated microfluidic chip with the function of DNA amplification. The integrated chip combines giant electrorheological-fluid actuated micromixer and micropump with a microheater array, all formed using soft lithography. Internal functional components are based on polydimethylsiloxane (PDMS) and silver∕carbon black-PDMS composites. The system has the advantages of small size with a high degree of integration, high polymerase chain reaction efficiency, digital control and simple fabrication at low cost. This integration approach shows promise for a broad range of applications in chemical synthesis and biological sensing∕analysis, as different components can be combined to target desired functionalities, with flexible designs of different microchips easily realizable through soft lithography. 相似文献
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Droplet microfluidics is a powerful method used to characterize chemical reactions at high throughput. Often detection is performed via in-line optical readout, which puts high demands on the detection system or makes detection of low concentration substrates challenging. Here, we have developed a droplet acoustofluidic chip for time-controlled reactions that can be combined with off-line optical readout. The principle of the platform is demonstrated by the enzymatic conversion of fluorescein diphosphate to fluorescein by alkaline phosphatase. The novelty of this work is that the time of the enzymatic reaction is controlled by physically removing the enzymes from the droplets instead of using chemical inhibitors. This is advantageous as inhibitors could potentially interact with the readout. Droplets containing substrate were generated on the chip, and enzyme-coupled microbeads were added into the droplets via pico-injection. The reaction starts as soon as the enzyme/bead complexes are added, and the reaction is stopped when the microbeads are removed from the droplets at a channel bifurcation. The encapsulated microbeads were focused in the droplets by acoustophoresis during the split, leaving the product in the side daughter droplet to be collected for the analysis (without beads). The time of the reaction was controlled by using different outlets, positioned at different lengths from the pico-injector. The enzymatic conversion could be measured with fluorescence readout in a separate PDMS based assay chip. We show the ability to perform time-controlled enzymatic assays in droplet microfluidics coupled to an off-line optical readout, without the need of enzyme inhibitors. 相似文献
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Spheroid culture is a preferable cell culture approach for some cell types, including hepatocytes, as this type of culture often allows maintenance of organ-specific functions. In this study, we describe a spheroid microarray chip (SM chip) that allows stable immobilization of hepatocyte spheroids in microwells and that can be used to evaluate drug metabolism with high efficiency. The SM chip consists of 300-μm-diameter cylindrical wells with chemically modified bottom faces that form a 100-μm-diameter cell adhesion region surrounded by a nonadhesion region. Primary hepatocytes seeded onto this chip spontaneously formed spheroids of uniform diameter on the cell adhesion region in each microwell and these could be used for cytochrome P-450 fluorescence assays. A row of microwells could also be connected to a microchannel for simultaneous detection of different cytochrome P-450 enzyme activities on a single chip. The miniaturized features of this SM chip reduce the numbers of cells and the amounts of reagents required for assays. The detection of four cytochrome P-450 enzyme activities was demonstrated following induction by 3-methylcholantlene, with a sensitivity significantly higher than that in conventional monolayer culture. This microfabricated chip could therefore serve as a novel culture platform for various cell-based assays, including those used in drug screening, basic biological studies, and tissue engineering applications. 相似文献
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In single cell analysis (SCA), individual cell-specific properties and inhomogeneous cellular responses are being investigated that is not subjected to ensemble-averaging or heterogeneous cell population effects. For proteomic single cell analysis, ultra-sensitive and reproducible separation and detection techniques are essential. Microfluidic devices combined with UV laser induced fluorescence (UV-LIF) detection have been proposed to fulfill these requirements. Here, we report on a novel microfluidic chip fabrication procedure that combines straightforward production of polydimethylsiloxane (PDMS) chips with a reduced UV fluorescence background (83%-reduction) by using PDMS droplets with carbon black pigments (CBP) as additives. The CBP-droplet is placed at the point of detection, whereas the rest of the chip remains transparent, ensuring full optical control of the chip. We systematically studied the relation of the UV background fluorescence at CBP to PDMS ratios (varying from 1:10 to 1:1000) for different UV laser powers. Using a CBP/PDMS ratio of 1:20, detection of a 100 nM tryptophan solution (S/N = 3.5) was possible, providing a theoretical limit of detection of 86 nM (with S/N = 3). Via simultaneous two color UV/VIS-LIF detection, we were able to demonstrate the electrophoretic separation of an analyte mixture of 500 nM tryptophan (UV) and 5 nM fluorescein (VIS) within 30 s. As an application, two color LIF detection was also used for the electrophoretic separation of the protein content from a GFP-labeled single Spodoptera frugiperda (Sf9) insect cell. Thereby just one single peak could be measured in the visible spectral range that could be correlated with one single peak among others in the ultraviolet spectra. This indicates an identification of the labeled protein γ-PKC and envisions a further feasible identification of more than one single protein in the future. 相似文献
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Na Xu Zhen-Feng Zhang Li Wang Bo Gao Dai-Wen Pang Han-Zhong Wang Zhi-Ling Zhang 《Biomicrofluidics》2012,6(3)
Microfluidic chip is a promising platform for studying virus behaviors at the cell level. However, only a few chip-based studies on virus infection have been reported. Here, a three-layer microfluidic chip with low shear stress was designed to monitor the infection process of a recombinant Pseudorabies virus (GFP-PrV) in real time and in situ, which could express green fluorescent protein during the genome replication. The infection and proliferation characteristics of GFP-PrV were measured by monitoring the fluorescence intensity of GFP and determining the one-step growth curve. It was found that the infection behaviors of GFP-PrV in the host cells could hardly be influenced by the microenvironment in the microfluidic chip. Furthermore, the results of drug inhibition assays on the microfluidic chip with a tree-like concentration gradient generator showed that one of the infection pathways of GFP-PrV in the host cells was microtubule-dependent. This work established a promising microfluidic platform for the research on virus infection. 相似文献
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Tsung-Ju Chen Jen-Kuei Wu Yu-Cheng Chang Chien-Yu Fu Tsung-Pao Wang Chun-Yen Lin Hwan-You Chang Ching-Chang Chieng Chung-Yuh Tzeng Fan-Gang Tseng 《Biomicrofluidics》2014,8(3)
Detection of individual target cells among a large amount of blood cells is a major challenge in clinical diagnosis and laboratory protocols. Many researches show that two dimensional cells array technology can be incorporated into routine laboratory procedures for continuously and quantitatively measuring the dynamic behaviours of large number of living cells in parallel, while allowing other manipulations such as staining, rinsing, and even retrieval of targeted cells. In this study, we present a high-density cell self-assembly technology capable of quickly spreading over 300 000 cells to form a dense mono- to triple-layer cell arrangement in 5 min with minimal stacking of cells by the gentle incorporation of gravity and peripheral micro flow. With this self-assembled cell arrangement (SACA) chip technology, common fluorescent microscopy and immunofluorescence can be utilized for detecting and analyzing target cells after immuno-staining. Validated by experiments with real human peripheral blood samples, the SACA chip is suitable for detecting rare cells in blood samples with a ratio lower than 1/100 000. The identified cells can be isolated and further cultured in-situ on a chip for follow-on research and analysis. Furthermore, this technology does not require external mechanical devices, such as pump and valves, which simplifies operation and reduces system complexity and cost. The SACA chip offers a high-efficient, economical, yet simple scheme for identification and analysis of rare cells. Therefore, potentially SACA chip may provide a feasible and economical platform for rare cell detection in the clinic. 相似文献
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Khoshmanesh K Akagi J Hall CJ Crosier KE Crosier PS Cooper JM Wlodkowic D 《Biomicrofluidics》2012,6(2):24102-2410214
The lack of technologies that combine automated manipulation, sorting, as well as immobilization of single metazoan embryos remains the key obstacle to high-throughput organism-based ecotoxicological analysis and drug screening routines. Noticeably, the major obstacle hampering the automated trapping and arraying of millimetre-sized embryos on chip-based devices is their substantial size and mass, which lead to rapid gravitational-induced sedimentation and strong inertial forces. In this work, we present a comprehensive mechanistic and design rationale for manipulation and passive trapping of individual zebrafish embryos using only hydrodynamic forces. We provide evidence that by employing innovative design features, highly efficient hydrodynamic positioning of large embryos on a chip can be achieved. We also show how computational fluid dynamics-guided design and the Lagrangian particle tracking modeling can be used to optimize the chip performance. Importantly, we show that rapid prototyping and medium scale fabrication of miniaturized devices can be greatly accelerated by combining high-speed laser prototyping with replica moulding in poly(dimethylsiloxane) instead of conventional photolithography techniques. Our work establishes a new paradigm for chip-based manipulation of large multicellular organisms with diameters well above 1 mm and masses often exceeding 1 mg. Passive docking of large embryos is an attractive alternative to provide high level of automation while alleviating potentially deleterious effects associated with the use of active chip actuation. This greatly expands the capabilities of bioanalyses performed on small model organisms and offers numerous and currently inaccessible laboratory automation advantages. 相似文献