Identify intronic microRNA with bioinformatics.

MicroRNAs (miRNAs) are single-strand nonprotein coding RAN with 18 to 25-nucleotides long. With complementary sequence to target messenger RNA (mRNA), miRNA regulates mRNA degradation and protein translation. miRNAs have been identified in various organisms ranging from virus to human. Increasing evidence indicates that mammalian gene regulation has multiple layers and the availability of mRNA is not the sole regulation mechanism. The evolutionally conserved miRNA may be a primary regulation mechanism of gene expression. Its role in directing embryo development and stem cell differentiation should not be underestimated.Due to the small size of miRNA, identifying it with experimental approach (e.g., direct cloning) is difficult. The cell type and developmental-specific expression of miRNA make the experimental approach even more difficult. Consequently, bioinformatics approaches have been developed to identify novel miRNA. In human miRNA study, many studies search for the mostly complete human genomic sequence. Here, we report a rapid bioinformatics approach to mine miRNA from gene specific introns. Intronic miRNA may directly regulate the expression of its target genes during development. The reported bioinformatics approach not only identifies the potential miRNA, but also provides the intron location of these miRNA like sequence. This information is critical for studying the gene-gene interaction via miRNA, and facilitates the study of miRNA in gene expression regulation.

Development of microfluidic chips for heterogeneous receptor-ligand interaction studies.

A simple microfluidic-based technique to quantitate the binding affinity between the glycopeptide antibiotics teicoplanin from Actinoplanes teicomyceticus and vancomycin from Streptomyces orientalis and 5-carboxyfluorescein-D-Ala-D-Ala-D-Ala (5-FAM-(DA)(3)) is described. In this work, (3-aminopropyl)triethoxysilane is used to modify the surfaces of a series of microchannels, and each channel is subsequently exposed to a solution of antibiotic for a few minutes. The antibiotic is retained after washing through electrostatic interactions, and the series of channels are subsequently exposed to an increasing concentration of 5-FAM-(DA)(3) followed by washing to exclude any nonspecific binding. The extent of fluorescence is quantified using a microscope fitted with a CCD camera. The binding constants for the interaction of teicoplanin and vancomycin with the fluorescent peptide were determined to be 6.03 +/- 0.97 x 10(4) and 4.93 +/- 1.13 x 10(4) M(-1), respectively, in good agreement with previous data. The ease of quantifying the extent of interaction in this microchip technique may prove powerful for exploration of a myriad of receptor-ligand pairs.