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  • 1
    ISSN: 1546-1696
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: [Auszug] The Human Proteome Organization (HUPO) recently completed the first large-scale collaborative study to characterize the human serum and plasma proteomes. The study was carried out in different locations and used diverse methods and instruments to compare and integrate tandem mass spectrometry ...
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  • 2
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR- Reduced expression of nm23-Hl, which encodes the nucleoside diphos-phate kinase A (ref. 1), is associated with a high potential for metastasis in some tumour types2, but its expression is increased in aggressive neuroblastoma, a childhood tumour of variable outcome3. To investigate the role of ...
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  • 3
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Horizontal two-dimensional (2-D) electrophoresis with immobilized pH gradients (IPG) in the first dimension, described for soluble proteins in Electrophoresis 1985, 6, 599-604, has been extended to an analysis of complex protein mixtures, such as leukemia cell proteins or bean proteins, in the presence of nonionic detergents. By optimizing the ratio of gel volumes for the first and second dimensional separation, and by decreasing the concentration of Nonidet P-40 in the IPG gel, undistorted protein patterns in the 2-D gel are obtained. Horizontal and vertical streaking are considerably diminished by optimized reswelling conditions of the dry IPG strips in presence of both urea and detergent. Resolution is improved and a reduced background is obtained when overcrowded gel areas are spread by flattening the pH gradient (in the first dimension) and the polyacrylamide gradient (in the second dimension).
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  • 4
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Quantitative analysis of polypeptide differences among sets of identically prepared two-dimensional polyacrylamide gels is facilitated by the use of mathematical transformations of the spot integrated intensity data for each gel in order to make comparisons. Such adjustments are needed because technical factors cause the stained polypeptide spots displayed on a particular gel to simultaneously appear darker or lighter than on another gel. We have compared three different adjustment schemes by applying each to the same set of data and testing to determine which gives smaller coefficients of variation for a large battery of spots. The adjustment that gave the best results is one based on regressing the spot integrated intensities of a standard gel versus each “target” gel and using the fitted line to transform the spot integrated intensities on the target gel. This adjustment is intuitive, easy to compute, and performed well regardless of whether the spots with large variability were included in the data or not.
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  • 5
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Since the introduction of immobilized pH gradient (IPG) electrophoresis, optimization of sample entry has been a major concern. Partial sample entry, associated with smearing of proteins, has led investigators to propose the use of hybrid IPG-carrier ampholyte focusing for adequate protein separation. We have examined the effects of adding carrier ampholytes to the protein sample, preelectrophoresis and the site of sample application on sample entry, resolution and pattern stability for IPG gels, used as a part of two-dimensional electrophoresis. The addition of carrier ampholytes to the sample increased the rate of entry of proteins into the gel while preelectrophoresis had an opposite effect. There was a substantial difference in protein entry between sample application at the anode vs. cathode. After an adequate focusing time the final focusing pattern was remarkably similar and consisted of several hundred well-resolved polypeptides, irrespective of the initial starting conditions. Therefore IPG electrophoresis, without addition of carrier ampholytes to the gel, results in the high resolution separation of complex protein mixtures.
    Additional Material: 5 Ill.
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  • 6
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: An approach for the computer-assisted analysis of two-dimensional gels has been developed as a part of our laboratory information processing system (LIPS). This approach relies in part on an algorithm for the pairwise matching of protein spots. The matching process initially matches spots based on a cross-correlational measure of how well neighboring spots align. While this first pass correctly determines most spot correspondences and noncorrespondences, it can make errors. Higher accuracy is obtained by monitoring the consistency of spot match decisions in a second pass, which demands that neighboring spot pairs that align spatially must also have been found to match in the first pass. Pairwise comparisons of gels are, combined into n-way comparisons by matching spot lists of gels to “master” gel spot lists, which in turn are matched to higher level masters, resulting in a hierarchy of matched spots. After each pairwise match the results are reviewed and corrected with the assistance of a graphical match-editor. Results are given for 19, single-Cell-derived lymphoid clones in which the presence of a mutation had previously been established, each processed in duplicate. Only one of 46 spot changes failed to be detected, which demonstrates that the strategy is sensitive and efficient for detecting qualitative spot differences.
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  • 7
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A laboratory information processing system (LIPS) has been developed to provide support for various laboratory activities related to two-dimensional electrophoresis. In this paper we present the relational schema for each level of activity and the application development of LIPS, in terms of the relational database management system being used. We also discuss our experience with the current system.
    Additional Material: 10 Ill.
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  • 8
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: There is a continuing need for more efficient methods to examine human (and other) populations for altered germinal and somatic cell mutation rates. To this end, we have explored the potential usefulness of two-dimensional (2-D) electrophoresis of human DNA fragments obtained from restriction-enzyme-digested genomic DNA, using samples from father/mother/child trios. On a single 2-D DNA preparation, approximately 2000 DNA fragments varying in size from 1.0 to 5.0 kbp in the first dimension and 0.3 to 2.0 kbp in the second dimension are visualized. To enter into a genetic analysis of quantitative variation, these fragments must exhibit positional and quantitative stability. With respect to the latter, if spots that are the product of two homologous DNA fragments are to be distinguished with the requisite accuracy from spots that are the product of only one fragment, the coefficient of variation of spot intensity should be approximately ≤ 0.12. At present, 482 of the spots in our preparations meet these standards. In an examination of preparations based on three Japanese mother/father/child trios, 43 of these 482 spots were found to exhibit variations that segregated within families according to Mendelian principles. Additionally, of the 2000 spots, 1114 (of which the aforementioned 482 are a subset) were deemed appropriate for the study of qualitative variation. A total of 142 variable spots were identified; the heterozygosity index for these DNA fragments was 4.4%. The genetic nature of the additional variants was again established by their segregation according to Mendelian principles. We have established the feasibility of cloning fragments from such gels and determining their nucleotide sequence. This technology should be highly efficient in monitoring for mutation resulting in loss/gain/rearrangement events in DNA fragments distributed throughout the genome.
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  • 9
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The feasibility of detecting quantitative genetic variants based on a decrease in the integrated intensity of polypeptide spots in two-dimensional polyacrylamide gels of human lymphoblastoid cell clones was investigated. A battery of 65 spots on 115 gels was studied to determine the distribution of quantitative measures for spots where no mutation had occurred. The corresponding distribution for spots which have decreased integrated intensity as a result of a mutation at one of two alleles coding for the spot was investigated by quantitating spots for which mutations were known to have occurred. These two distributions allowed the estimation of the rates of false positive and false negative errors for any particular strategy aimed at detecting null mutations, and thus provides a basis for the design of efficient strategies. Our silver stained gels have sufficient reproducibility of spot integrated intensities so that, for situations in which the mutation rate is relatively high, it is practical to monitor a sub-set of spots for null variants using the same digitized images as are used to detect structural variants.
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  • 10
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Horizontal two-dimensional (2-D) electrophoresis with immobilized pH gradients (IPG) in the first dimension for buffer soluble proteins and for complex proteins solubilized in the presence of Nonidet P-40 (Görg et al., Electrophoresis 1987, 8, 45-51), has been extended to analyze basic proteins of yeast cells focused under non-equilibrium and equilibrium conditions. Transient state isoelectric focusing (IEF) in IPG gels revealed sample smearing and background staining, displaying horizontal streaks in the resultant 2-D patterns. Inclusion of 0.5 % carrier ampholytes (CA) to the IPG gel (IPG-CA), resulted in the formation of many sharp protein bands after transient state IEF with resultant distinct spots in the 2-D patterns; however, resolution was poor and the gel contained heavy background staining. With prolonged focusing time, background staining disappeared and there was less difference in the final steady state IEF patterns obtained with IPG and IPG-CA. Reduction of the Immobiline concentration to one third the manufacturer's recommended amount did not improve IEF resolution with respect to streaking and background staining under either transient state or equilibrium conditions. In general, spot intensities were less on 2-D gels using diluted IPG gels than with “standard” IPG gels. Optimization of 2-D electrophoresis with IPGs in the first dimension was strongly related to IEF conditions. The use of IPG gels focused to equilibrium should not only improve inter-gel reproducibility and resolution but also the quality of the final 2-D patterns with respect to background staining and horizontal streaking.
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