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.

Polyelectrolyte-Coated Size-Exclusion Ion-Exchange Particles

Abstract: A polyelectrolyte-coated particle, devices for using the particle, methods for using the particle for separating PCR reaction products and/or DNA sequencing reaction products, and compositions for coating the particle are provided.

Method of extracting intensity data from digitized image

Abstract: A method for reducing optical crosstalk in an optical array detector is provided (701). In various embodiments, the method can include measuring optical emission within a first region of interest (ROI) using a first plurality of pixels of the optical array detector, wherein each of the first plurality of pixels provides a value for optical signal intensity within the first ROI. An ROI sum signal can then be calculated by summing the values for optical signal intensity measured by the first plurality of pixels. An optical emission within a second ROI can be measured using a second plurality of pixels of the optical array detector, wherein each of the second plurality of pixels provides a value for optical signal intensity within the second ROI. The values for optical signal intensity provided by the second plurality of pixels can be algebraically manipulated to determine an optical crosstalk signal. A corrected ROI optical signal intensity can then be determined by multiplying the optical crosstalk signal by a number of pixels of the first plurality of pixels and subtracting the multiplied optical crosstalk signal from the ROI sum signal.

Letter to the editor--nomenclature and allele repeat structure update for the Y-STR locus GATA H4.

Abstract: Sir: Establishing a consensus nomenclature can facilitate data comparison for proficiency testing, quality assurance, and casework results. Efforts into nomenclature standardization should be supported and lauded. The DNA Commission of the International Society of Forensic Genetics (ISFG) has issued new recommendations on the nomenclature and specifically addressed the Y GATA H4 marker (1). There are differences in allele designations at the GATA H4 marker between those recommended in the Applied Biosystems AmpFlSTR Yfiler polymerase chain reaction amplification kit (Applied Biosystems, Foster City, CA) and the ISFG recommendations. The nomenclature for the GATA H4 marker in the Yfiler kit is based on the allele repeat structure defined by the National Institute of Standards and Technology Standard reference material (SRM) 2395 and the work of Butler et al. (2). In the Yfiler kit the variable core repeat (TAGA) is used to designate the alleles (such as alleles 8–13 in the allelic ladder of the Yfiler kit) (3,4). Furthermore, the Yfiler kit primers amplify the region now designated as the GATA H4.1 locus as defined by Gusmao et al. (5) and recommended by the ISFG Commission. The GATA H4.1 locus structure consists of a core repeat region designated as AGAT and nonvariable tetranucleotide repeats ((AGAT)4CTAT(AGAT)2(AGGT)3(AGAT)n) that are considered for allele number designation under the ISFG recommendations. Thus, there is a difference in allele nomenclature that depends on whether or not the nonvariable region is included. Those who choose to follow the allele nomenclature recommendations of the ISFG Commission should add a correction factor of nine to the Yfiler allele number, and they should refer to this marker as GATA H4.1. Employing the ISFG proposed allele designation for GATA H4.1 changes the Yfiler kit allelic ladder range from 8–13 to 17–22. Alternatively, those who amplify the entire GATA H4 region (GATA H4.1 and GATA H4.2) should add a correction factor of 16 to the Yfiler kit allele number. In this case, the Yfiler kit allelic ladder for GATA H4 ranges from 24 to 29.

LNA incorporated siRNAs exhibit lower off-target effects compared to 2'-OMethoxy in cell phenotypic assays and microarray analysis.

Abstract: Despite the promise of short interfering RNAs (siRNA), contending with off-target is a challenge for RNAi users. To alleviate these problems, we have developed locked nucleic acid (LNA) modified siRNAs and optimized performance using cellular phenotypic assays as well as microarray analysis. During development, we compared LNA and 2'OMethoxy (2'OMe) chemistries placed strategically throughout the siRNA molecule and found a novel pattern of LNA placement that greatly improved the specificity of the siRNA and reduced it's toxicity in culture while preserving the potency of the siRNA. The improvements in specificity made by LNA-modified siRNAs were developed and validated by measuring the phenotypic signatures in a high content cell-based screening assay as well as comparison of the level of differentially expressed genes observed in microarray analysis between modified and unmodified siRNAs. HT screening of a collection of genes demonstrated that the LNA-modified siRNAs exhibits the best overall rate to elicit the expected phenotype, reduced toxicity and achieved an improved coherence of phenotype compared to 2'OMe-modified or unmodified siRNAs.

Brazil nuts: determination of natural elements and aflatoxin

Abstract: A study was carried out to evaluate the association of levels of radioactivity, selenium and aflatoxin in shelled Brazil nuts, which were classified in different sizes, for export. The selenium determinations were performed by inductively coupled plasma optical emission spectrometry (LOQ = 3.0 µg g -1 ), and aflatoxins were detected by Liquid chromatography-mass spectrometry (LOQ = 0.85 µg kg -1 ), recovery rates were between 92 and 100%. Radioactivity was measured by high-resolution gamma spectrometry. The selenium mean concentration was (22.7 ± 7.4) µg g -1 . (n = 30). Mean activities determined for the following radium isotopes were: 15.77 Bq kg -1 for 224 Ra, 104.8 Bq kg for 226 Ra and 99.48 Bq kg -1 for 228 Ra. For 226 Ra, the levels did not vary significantly with nut sizes, although such differences were observed for 224 Ra and 228 Ra. There was no statistically significant association between the level of selenium and the activity of radionuclides, however, there was correlation between the radionuclides. Aflatoxins above the quantification limit were not found.