G4 Generation Research Articles

Fad alleles of PS1 and PS2 have divergent effects on skeletal development, γ-40 and γ-42-secretase

To express human granulocyte-macrophage colony-stimulating factor (hGM-CSF) gene in the silk glands of transformation silkworm (Bombyx mori) based on gene-targeting, two fragments from fibroin heavy chain gene (fib-H) of silkworm were cloned and sequenced. One fragment contains the 1st exon and its downstream 1st intron’s partial sequence; and the other fragment contains the 1st intron’s partial sequence and the 2nd exon’s partial sequence. Then the two fragments, as homologous arm, were inserted into pSK to generate a gene-targeted vector, pSK-HL-A3GFP-FLP-GM-CSF-FLPA-HR in which a gfp gene driven by A3 promoter and an hGM-CSF gene under the control of fibroin light chain (fib-L) promoter were included. The vector was transferred into the silkworm eggs using sperm-mediated gene transfer. After being screened for green fluorescent, the transformation silkworm was obtained, whose genome was verified by PCR and dot hybridization to confirm whether the target genes had been integrated into the silkworm genome. Furthermore, in the posterior silk glands of the G4 generation transformation silkworms, a specific band with the molecular weight of 22 kDa could be detected by Western blotting with an antibody against hGM-CSF, and the expression level of the hGM-CSF estimated by ELISA was approximately 1.26 ng per gram fresh posterior silk gland.

Convergent synthesis of starburst poly(ether ketone) dendrons

New highly branched starburst poly(ether ketone) dendrons were synthesized by the convergent approach through aromatic nucleophilic substitution reactions. 3,5-Bis(4-fluorobenzoyl)anisole was used as the building block, where the methoxy group was a protected form of the hydroxy group. The reaction of the building block with phenol gave the first-generation dentron (G1). Next, after the methoxy group was converted to a hydroxy group by reaction with aluminum chloride, the resulting phenol functionality of G1-OH was allowed to react with the building block to yield the second-generation dendron (G2). By repeating these procedures G3 and G4 generation dendrons possessing 8 and 16 phenoxy groups, respectively, at the periphery position were obtained