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Most commonly used intercalating fluorescent dyes in DNA detection are lacking any sequence specificity, whereas so-called Exciton Primers can overcome this limitation by functioning as 'sequence-specific dyes.' After hybridization to complementary sequences, the fluorescence of Exciton Primers provides sequence-specific signals for real-time monitoring of amplification reactions. Applied to the SmartAmp2 mutation detection process, Exciton Primers show high signal strength with low background leading to a superior specificity and sensitivity compared to SYBR Green I. Signal strength can be further enhanced using multiple dyes within one Exciton Primer or use of multiple Exciton Primers in the same amplification reaction. Here we demonstrate the use of Exciton Primers for genotyping a single nucleotide polymorphism (SNP) in the VKORC1 locus (−1639G>A) relevant for Warfarin dosing as an example for Exciton Primers mediated genotyping by SmartAmp2. The genotyping assay can use only one labeled Exciton Primer for endpoint detection, or simultaneously by real-time monitoring detect wild-type and mutant alleles in a one-tube reaction using two Exciton Primers having different dyes. Working directly from blood samples, Exciton Primer mediated genotyping by SmartAmp2 offers superior solutions for rapid point-of-care testing. Hum Mutat 31:208-217, 2010. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

We found a novel 52 kDa matrix glycoprotein MPP1 in the shell of Crassostrea nippona that was unusually acidic and heavily phosphorylated. Deduced from the nucleotide sequence of 1.9 kb cDNA, which is likely to encode MPP1 with high probability, the primary structure of this protein shows a modular structure characterized by repeat sequences rich in Asp, Ser and Gly. The most remarkable of these is the DE-rich sequence, in which continuous repeats of Asp are interrupted by a single Cys residue. Disulfide-dependent MPP1 polymers occurring in the form of multimeric insoluble gels are estimated to contain repetitive locations of the anionic molecules of phosphates and acidic amino acids, particularly Asp. Thus, MPP1 and its polymers possess characteristic features of a charged molecule for oyster biomineralization, namely accumulation and trapping of Ca2+. In addition, MPP1 is the first organic matrix component considered to be expressed in both the foliated and prismatic layers of the molluscan shell microstructure. In vitro crystallization assays demonstrate the induction of tabular crystals with a completely different morphology from those formed spontaneously, indicating that MPP1 and its polymers are potentially the agent that controls crystal growth and shell microstructure. [ABSTRACT FROM AUTHOR]

Mollusks make their shells by biomineralization using Ca2+ and CO3 2− from natural environment. In molluscan shells, two types of CaCO3 crystal which are aragonite and calcite form the species-dependent microstructures. It is believed that shell organic matrices act for control of the crystal types and microstructures. Shell of Pinctada fucata is divided into aragonitic nacreous layer and calcitic prismtic layer. In the recent years, several novel matrix components have been identified in pearl oyster shells by subsequent solubilization of the insoluble matrix, even in the nacreous layer which abounds in the data. In them, we focused our attention on a component, of which the N-terminal amino acid sequence was determined, and attempted cloning genes encoding it. As a result, several clones with typical sequence for the ORF (open reading frame) region were identified and the amino acid sequences were deduced. Further analysis of northern hybridization clarified the tissue specific expressions of the transcripts of the identified genes. [ABSTRACT FROM AUTHOR]