ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Two-dimensional polyacrylamide gel electrophoresis  (29)
  • Wiley-Blackwell  (29)
  • 1
    ISSN: 0173-0835
    Keywords: Apolipoprotein E ; Immobilized pH gradient ; Phenotyping ; Immunoblotting ; Two-dimensional polyacrylamide gel electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Apolipoprotein E (apo E) is a normal component of several classes of plasma lipoproteins. Apo E phenotypes are closely related to total cholesterol, low density lipoprotein (LDL)-cholesterol and apo B concentration. The apo E 2/2 phenotype is related to the type III hyperlipoproteinemia due to the defective binding of apo E-2 to the hepatic receptors. The apo E 4/4 phenotype has been reported to be present in most elderly people suffering from the Alzheimer disease, and is associated with increased risk of coronary heart disease and Creutzfeld-Jakob disease. Therefore, apo E phenotyping is essential. The method described here uses a precast immobilized pH gradient, avoids time-consuming separation of lipoproteins from plasma, needs no pretreatment with neuraminidase and involves highly sensitive enhanced chemiluminescence for visualization. Therefore it has many advantages over previously published methods.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 0173-0835
    Keywords: Yeast ; SWISS-2DPAGE ; Two-dimensional polyacrylamide gel electrophoresis ; Protein database ; Protein mapping ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: The systematic sequencing of the yeast genome will soon be completed. A new challenge has been launched by the EUROFAN (European Functional Analysis) project whose goal is to elucidate the physiological and biochemical function of newly discovered open reading frames (ORF) from yeast. One of the approaches is to use protein-based technologies such as two-dimensional gel eletrophoresis and protein identification in order to establish a yeast reference map. Modified protein patterns can be compared to the reference map which hopefully will help identify changes related, for example, to growth processes or developmental events. This paper describes the yeast SWISS-2DPAGE database in which charge separation was obtained using immobilized pH gradient (IPG). Proteins identified by gel comparison, amino acid composition analysis and/or microsequencing are recorded and described in an accessible uniform format. We have identified more than one hundred polypeptides, several of which were newly mapped. In addition, the yeast SWISS-2DPAGE database can be freely accessed through the World Wide Web (WWW) network on the ExPASy molecular biology server.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0173-0835
    Keywords: Testis ; Spermatogenesis ; In vitro translation ; Two-dimensional polyacrylamide gel electrophoresis ; Two-dimensional polyacrylamide gel electrophoresis ; Protein map ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: During mammalian spermatogenesis meiotic cell division and spermiogenesis occurs. Gene expression during this process is temporally regulated at the transcriptional and translational levels but the mechanisms are not well understood. In this publication we have investigated the synthesis of proteins in vitro to detect the proteins with a high metabolic turnover and to compare them with the in vivo protein map. RNA of spermatocytes and round spermatid cell populations, purified by centrifugal elutriation, and total testis was isolated. The poly A+ mRNA fraction was translated using a rabbit reticulocyte lysate. The translation products were separated by two-dimensional (2-D) gel electrophoresis using nonlinear 3.5-10 immobilized pH gradients for the first-dimensional separation. The gels with 35S-translated proteins were transferred onto polyvinylidene difluoride (PVDF) membranes and scanned using a phosphorimager. A highly reproducible and complex protein pattern was obtained using this methodology. Only rat testis messages were translated. Using Melanie 2 software we could compare and detect more than 1000 proteins on 2-D radioactive images. Some changes could be observed in protein expression between the different cell types but they were not statistically significant. The comparison between the 2-D rat testis map and the in vitro translated patterns show no matching between any spots. This result suggests that the post-transcriptional modifications occurring in the reticulocyte system are not the same as those that occur in vivo in the testis. Rabbit reticulocyte proteins were detected by staining PVDF membranes with colloidal gold. Rat testis and reticulocyte patterns were completely different.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 0173-0835
    Keywords: Two-dimensional polyacrylamide gel electrophoresis ; Antibodies monoclonal diagnostic use ; Colonic neoplasms ; Rectal neoplasms ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Large tissue samples from ten patients operated for colorectal cancer were prepared in the operating room in iced phosphate buffered saline, containing ethylene diaminetetraacetic acid and protease inhibitors. After cutting the specimens into small fragments, the tissues were gently pressed through a steel mesh. Membranes were permeabilized in chilled ethanol 70% to allow cytosolic fluoresceine isothiocyanate labeling, performed with anti-cytokeratin (CAM 5.2) antibodies. Samples were quantitatively sorted with a fluorescence activated cell sorter (FACS) and denatured before processing separation by two-dimensional electrophoresis on polyacrylamide gels. This procedure made it possible to sample about 4 × 107 viable normal and tumoral cells before fixation, and up to 4 × 106 cells after FACS. The gels run before and after fixation showed no major differences. The rate of cytokeratin-positive cells in the samples was the following (mean, Cl 5-95%): mucosa 29.5% (8.9-66.7%), tumor 44.3% (6.6-94.8%). The epithelial cell content in colorectal cancer and normal mucosa shows important intersample variations. This is important for any comparison of fresh samples, whether at DNA, RNA, or at the protein level. We propose a method allowing the preparation of pure epithelial cell samples from normal and tumoral colonic fresh mucosa.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0173-0835
    Keywords: Membrane proteins ; Solubility ; Two-dimensional polyacrylamide gel electrophoresis ; Proteome ; Escherichia coli ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: We describe the extraction and enrichment of membrane proteins for separation by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) after differential solubilization of an Escherichia coli cell lysate. In a simple three-step sequential solubilization protocol applicable for whole cell lysates, membrane proteins are partitioned from other cellular proteins by their insolubility in solutions conventionally used for isoelectric focusing (IEF). As the first step, Tris-base was used to solubilize many cytosolic proteins. The resultant pellet was then subjected to conventional solubilizing solutions (urea, 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, dithiothreitol, Tris, carrier ampholytes). Following the completion of this step, 89% of the initial E. coli sample mass was solubilized. Finally, the membrane protein rich pellet was partially solubilized using a combination of urea, thiourea, tributyl phosphine and multiple zwitterionic surfactants. Using N-terminal sequence tagging and peptide mass fingerprinting we have identified 11 membrane proteins from this pellet. Two of these outer membrane proteins (Omp), OmpW and OmpX, have previously been known only as an open reading frame in E. coli, while OmpC, OmpT and OmpTOLC have not previously been identified on a 2-D gel. The prefractionation of an entire cell lysate into multiple fractions, based on solubility, results in simplified protein patterns following 2-D PAGE using broad-range pH 3.5-10 immobilized pH gradients (IPGs). Additional advantages of sample prefractionation are that protein identification and gel matching, for database construction, is a more manageable task, the procedure requires no specialized apparatus, and the sequential extraction is conducted in a single centrifuge tube, minimizing protein loss.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 0173-0835
    Keywords: Glycoprotein ; Two-dimensional polyacrylamide gel electrophoresis ; α1-Antitrypsin ; α2-HS Glycoprotein ; Protein isoforms ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Two-dimensional (2-D) electrophoresis is the preferred method for separating the glycoforms of proteins. The isoforms usually present as ‘trains’ of spots in the first dimension and may also differ in molecular weight. The primary goal for analyzing the carbohydrate content of glycoprotein spots is to understand the ‘rules’ which govern the migration of glycoproteins in 2-D electrophoresis. These rules can then be used to produce predictive vectors to interpret changes in glycosylation patterns. Techniques for the analysis of oligosaccharides released from glycoproteins which have been electroblotted to PVDF membrane after one-dimensional (1-D) and 2-D preparative gel electrophoresis are described. The oligosaccharides are removed enzymatically (PNGase F of N-linked oligosaccharides) or chemically (β-elimination of O-linked oligosaccharides) and separated by high performance anion exchange chromatography (HPAEC-PAD) and identified by electrospray ionization mass spectrometry (ESI-MS) or analyzed directly by ESI-MS. After enzymic removal of the N-linked oligosaccharides the protein spots can be further analyzed by Edman sequence tagging for identification and quantitation of the protein and by acid hydrolysis for monosaccharide analysis of the O-linked oligosaccharides. These approaches have been proved on 1-D PAGE electroblotted bovine fetuin and human glycophorin A and then used to analyze two abundant proteins which separate as glycoforms on 2-D PAGE preparative narrow range (pH 4.5-5.5) blots of human plasma: α2-HS glycoprotein (human fetuin) and α1-antitrypsin (α1-protease inhibitor). It is apparent that both the macroheterogeneity (site occupation) and microheterogeneity (diversity of structures) of the glycosylation contribute to the separation of protein isoforms in 2-D PAGE.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0173-0835
    Keywords: Melanie ; Computer analysis ; Two-dimensional polyacrylamide gel electrophoresis ; World Wide Web ; Federated database ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Although two-dimensional electrophoresis (2-DE) computer analysis software packages have existed ever since 2-DE technology was developed, it is only now that the hardware and software technology allows large-scale studies to be performed on low-cost personal computers or workstations, and that setting up a 2-DE computer analysis system in a small laboratory is no longer considered a luxury. After a first attempt in the seventies and early eighties to develop 2-DE analysis software systems on hardware that had poor or even no graphical capabilities, followed in the late eighties by a wave of innovative software developments that were possible thanks to new graphical interface standards such as XWindows, a third generation of 2-DE analysis software packages has now come to maturity. It can be run on a variety of low-cost, general-purpose personal computers, thus making the purchase of a 2-DE analysis system easily attainable for even the smallest laboratory that is involved in proteome research. Melanie II 2-D PAGE, developed at the University Hospital of Geneva, is such a third-generation software system for 2-DE analysis. Based on unique image processing algorithms, this user-friendly object-oriented software package runs on multiple platforms, including Unix, MS-Windows 95 and NT, and Power Macintosh. It provides efficient spot detection and quantitation, state-of-the-art image comparison, statistical data analysis facilities, and is Internet-ready. Linked to proteome databases such as those available on the World Wide Web, it represents a valuable tool for the “Virtual Lab” of the postgenome area.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 0173-0835
    Keywords: Colonic neoplasms ; Rectal neoplasms ; Two-dimensional polyacrylamide gel electrophoresis ; Cell separation ; Antibodies' monoclonal diagnostic use ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: New diagnostic and prognostic markers are needed in colorectal cancer. They can be found by differential analysis at DNA, RNA or protein level. The accuracy of phenotypic comparisons of tumor and normal tissues depends on the purity of the samples. We present an effective method to identify and isolate proteins that are differentially expressed under altered conditions, and a two-dimensional reference protein map of the normal human colonic epithelium Normal colonic mucosa, primary tumors and liver metastases were prepared in the operating room. After washing in an ice-cold medium containing protease inhibitors, crypts were isolated by mechanical preparation without using metalloproteinases. Epithelial cells were then selected using Ber-EP4 Dynabeads. The samples were denaturated before processing for immobilized pH gradient two-dimensional polyacrylamide gel electrophoresis according to SWISS-2DPAGE standards. The samples contained more than 95% epithelial cells as confirmed by fluorescence-activated cell sorting using pan-anticytokeratin antibodies. Cell surfaces were not damaged, as assessed by scanning electronic microscope. A protein reference map of the normal colonic epithelium was defined. Using gel matching, N-terminal sequencing and/or immunoblotting techniques, 60 polypeptides - including proteins specifically expressed in colorectal epithelium - have now been identified. This reproducible method of sample preparation permits the comparison of protein patterns found in various pathological states with the present reference map (http://www.expasy.ch). Some of these patterns might provide diagnostic or prognostic markers, or even molecular targets for therapy in the future.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 0173-0835
    Keywords: Proteome ; Genome ; Two-dimensional polyacrylamide gel electrophoresis ; Post-translational modifications ; Vector maps ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0173-0835
    Keywords: Two-dimensional polyacrylamide gel electrophoresis ; Edman degradation ; Proteome ; Sequence tag ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Advances in protein database design and the software used to access the sequence data has led to progress in using protein attributes such as amino acid composition and peptide masses to identify proteins separated by two-dimensional electrophoresis. However, Edman degradation remains the principal technique for protein identification and it presents a significant bottle-neck in the progress towards rapid protein identification. Simple modifications to the sequencing hardware, which automate the delivery of protein spots into the sequencer, and parallel sequencing of the protein spots represent a significant advance in the use of Edman degradation to rapidly generate the powerful protein attribute, an N-terminal sequence tag.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...