Applied Biosystems

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

Method, system and apparatus for multiplexing ions in MSn mass spectrometry analysis

Abstract: A method and apparatus for multiplexing ions in an MSn mass spectrometer is provided. Ion are filtered to produce a group of ions of interest, the group of ions below a space charge limit of the MSn mass spectrometer. At least a portion of the group of ions are fragmented to form a fragmented group of ions. At least a portion of the fragmented group are stored such that a plurality of portions of the fragmented group can be sequentially selected for mass spectrometry analysis. Each of the plurality of portions of the fragmented group are sequentially selected and re-fragmented prior to mass spectrometry analysis. Each of the plurality of portions of the fragmented group are analyzed, via mass spectrometry, once each of the plurality of portions of the fragmented group has been fragmented.

Sequence of mouse glucose-6-phosphate dehydrogenase cDNA.

Abstract: A full-length mouse glucose-6-phosphate dehydrogenase (G6PD) cDNA has been isolated and sequenced, and the evolutionary conservation of many portions of the sequence has been verified by comparison with that of human and other sources.

Rapid Analysis of Cocaine and Metabolites in Urine Using a Completely Automated Solid-Phase Extraction-High-Performance Liquid Chromatography-Tandem Mass Spectrometry Method

Abstract: A rapid, simple, and completely automated method for the analysis of cocaine and its metabolites in urine has been developed. The method utilizes online solid-phase extraction (SPE) with liquid chromatographic separation and tandem mass spectrometric detection (MS‐MS). An efficient online SPE procedure was developed using Hysphere™ MM anion sorbent. A gradient chromatography method with a Gemini C6-Phenyl (50 ◊ 3.00-mm i.d., 5 µm) column was used for the separation of all compounds. Detection was by positive ion mode electrospray ionization MS‐MS. Multiple reaction monitoring (MRM) was used to enhance the selectivity and sensitivity of the method. Two MRM transitions were monitored for each analyte and one transition for each internal standard. Linearity was analyte-dependent but generally ranged from 7 to 1000 ng/mL. The limits of detection for the method ranged from 3 to 23 ng/mL and the limits of quantitation ranged from 7 to 69 ng/mL. Quality control (QC) samples were analyzed for each analyte in triplicate at 50, 200, and 800 ng/mL. The bias and precision were determined using a simple analysis of variance (ANOVA: single factor). The results demonstrated bias as < 5% and % precision as < 9% for all components at each QC level.

Rapid detection of Listeria monocytogenes in dairy samples utilizing a PCR-based fluorogenic 5' nuclease assay

Abstract: The presence of Listeria monocytogenes as a dairy food contaminant is a lethal threat to dairy industrialists; therefore, products tainted with L monocytogenes must be quickly detected and removed from production This fluorogenic PCR-based assay was developed to rapidly detect L monocytogenes contamination in dairy samples before a final product is distributed The detection method employed uses a PCR primer pair and a fluorogenic TaqMan probe which bind to a region of a virulence determinant gene specific to L monocytogenes As the DNA target is amplified, the 5′ nuclease activity of Taq DNA polymerase hydrolyzes the internal fluorogenic probe creating a change in fluorescence that can be monitored and automatically analyzed with a fluorometer Sensitivity studies indicated a lower detection limit of under 10 CFU for pure culture extracts and spiked dairy enrichments A study was performed on 266 dairy product samples obtained from Central California dairy production plants Eighty-three of these samples were artificially spiked with both high and low concentrations of L monocytogenes before an overnight enrichment in TSB/LiCl/colostin sulfate/moxalactam media DNA from enriched samples was obtained using a rapid Chelex extraction specifically designed for dairy sample enrichments and automated analysis The extraction was followed by the fluorogenic PCR assay and measurement of fluorescence increase The assay was completed within 24 h, with an observed 952% sensitivity, 967% specificity, 929% positive predictive value, 978% negative predictive value, and 962% accuracy According to specificity studies, five other bacterial species cross-reacted with the fluorogenic 5′ nuclease PCR However, only one of these strains (Listeria grayi) was able to grow in the enrichment medium employed, and was not isolated from any of the 266 dairy product enrichments evaluated in this study Therefore, this method provides a rapid, sensitive, and automatable analysis alternative to standard culture techniques for the detection of Listeria monocytogenes in dairy samples

Gene-environment interactions between the codon 194 polymorphism of XRCC1 and antioxidants influence lung cancer risk.

Abstract: X-ray repair cross complementing group 1 (XRCC1) is a DNA repair gene whose polymorphisms appear to influence the risk of lung cancer. We explored the influence of antioxidants on the association between the codon 194 arganine to tryptophan substitution polymorphism of XRCC1 and lung cancer risk. In a case-control study nested within a cohort of tin miners the cases were those diagnosed with lung cancer over 6 years of follow-up (n = 108). Two controls, matched on age and sex, were selected for each case by incidence density sampling. Individuals with the variant Arg194Trp allele seemed to be at lower risk for lung cancer (odds ratio (OR): 0.7, 95% confidence interval (95%CL): 0.4-1.2). Furthermore, high serum alpha-tocopherol (OR: 0.4, 95%CL: 0.2-0.9) and retinol (OR: 0.4, 95%CL: 0.2-0.9) levels were associated with significantly reduced risk of lung cancer among individuals with the Arg194Trp variant allele, but not among individuals with the wild-type genotype. In addition, the Arg194Trp variant reduced the risk of lung cancer associated with increased serum carotenoids compared to those with the homozygous wild-type allele. Our results show that Arg194Trp XRCC1 variant modifies the association between serum antioxidants and lung cancer risk.