Applied Biosystems

About: Applied Biosystems is a based out in . It is known for research contribution in the topics: Mass spectrometry & Nucleic acid. The organization has 1521 authors who have published 1579 publications receiving 285423 citations.

Derivatization of phosphorylated peptides with S- and N-nucleophiles for enhanced ionization efficiency in matrix-assisted laser desorption/ionization mass spectrometry.

Abstract: The identification of phosphorylation sites is essential for a full understanding of the cellular functions of proteins. However, mass spectrometric analysis is often hampered by the low abundance of phosphoproteins, the difficulty of obtaining full sequence coverage by specific proteolysis reactions, and the low ionization efficiency of phosphopeptides compared with their non-phosphorylated analogs. In the present work a beta-elimination/Michael addition was used to replace the phosphate groups of pSer or pThr by a group which gives rise to an enhanced ionization efficiency. In order to find optimum reaction conditions, beta-elimination/Michael addition was examined using phosphorylated model peptides. Whereas complete elimination of phosphate could be achieved by treatment with barium hydroxide in organic solvents such as ethanol or acetonitrile, the yield of the Michael adduct strongly depended on the nucleophile and the peptide sequence. Reaction with 2-phenylethanethiol, p-bromophenethylamine and ethylenediamine clearly resulted in products showing higher matrix-assisted laser desorption/ionization (MALDI) signal intensities compared with those of the corresponding phosphorylated precursors. The method was successfully used to identify phosphorylated sequences of ovalbumin and human Stat1 by in-gel derivatization with 2-phenylethanethiol and subsequent peptide mass fingerprint analysis of the trypsin digests. Copyright © 2004 John Wiley & Sons, Ltd.

Modified surfaces as solid supports for nucleic acid purification

Abstract: The invention relates to methods of separating polynucleotides, such as DNA, RNA and PNA, from solutions containing polynucleotides by reversibly binding the polynucleotides to a solid surface, such as a magnetic microparticle.

Systems, methods and apparatus for single molecule sequencing

Abstract: An embodiment generally relates to a system for analysis of an analyte. The system can include a transparent substrate. The system also includes an excitation light source configured to induce an evanescent wave excitation of a fluorescently labeled molecule near the access to the transparent substrate and a detector for detecting the fluorescently labeled molecule.

Expression profiling and cross-species RNA interference (RNAi) of desiccation-induced transcripts in the anhydrobiotic nematode Aphelenchus avenae.

Abstract: Background Some organisms can survive extreme desiccation by entering a state of suspended animation known as anhydrobiosis The free-living mycophagous nematode Aphelenchus avenae can be induced to enter anhydrobiosis by pre-exposure to moderate reductions in relative humidity (RH) prior to extreme desiccation This preconditioning phase is thought to allow modification of the transcriptome by activation of genes required for desiccation tolerance