No abstract

Several important properties of poly(3-hydroxybutyric-co-3-hydroxyvaleric acids) (P(3HB-co-3HV) depend mainly on the HV unit fraction of the copolymer. Sequential and simultaneous feeding of glucose and valerate were employed to produce P(3HB-co-3HV) in a fed-batch culture of Ralstonia eutropha, and the effects of feeding models on the cell growth, 3HV unit fraction, and copolymer productivity have been investigated. The sequential feeding of glucose and then valerate resulted in a cell density of 110.2 g/L, 3HV unit fraction of 62.7 mol %, and copolymer productivity of 0.56 g/(L.h), while the latter simultaneous feeding strategy never achieved the 3HV fraction of P(3HB-co-3HV) higher than 50%. A nuclear magnetic resonance study confirmed that the production of random copolymer P(3HB-co-3HV) with high 3HV unit fraction was possible even with sequential feeding of glucose and valerate.

A reliable multiplex assay procedure to detect human genetic mutations in the breast cancer susceptibility gene BRCA1 using zip-code microarrays and single base extension (SBE) reactions is described. Multiplex PCR amplification was performed to amplify the genomic regions containing the mutation sites. The PCR products were then employed as templates in subsequent multiplex SBE reactions using bifunctional primers carrying a unique complementary zip sequence in addition to a mutation-site-specific sequence. The SBE primers, terminating one base before their mutation sites, were extended by a single base at a mutation site with a corresponding biotin-labeled ddNTP. Hybridization of the SBE products to zip-code microarrays was followed by staining with streptavidin-Cy3, leading to successful genotyping of several selected BRCA1 mutation sites with wild-type and heterozygote mutant samples from breast cancer patients. This work has led to the development of a reliable DNA microarray-based system for the diagnosis of human genetic mutations.