1,720,966 research outputs found
Covalent attachment of streptavidin on colloidal gold nanoparticles and its characterization
No full text
Array-based mutation detection of the BRCA genes using direct probe/target hybridization methods
No full textHigh-level secretory production of human granulocyte-colony stimulating factor by fed-batch culture of recombinant Escherichia coli
No full textSecretory production of human granulocyte colony-stimulating factor fusion protein (hG-CSF) by fed-batch culture of Escherichia coli was investigated in both 2.5-L and 30-L fermentors, To develop a fed-batch culture condition that allows efficient production of hG-CSF, different feeding strategies including pH-stat, exponential and constant feeding were examined. Among these, the constant feeding strategy (0.228 g glucosexmin(-1)) and the exponential feeding that supports a low specific growth rate (mu=0.116 h(-1)) resulted in the best hG-CSF production. Under these conditions, 4.4 gxL(-1) of hG-CSF was produced. The effect of induction time on the protein production was also investigated. For the fed-batch cultures carried out with the pH-stat and exponential feeding strategies, induction at higher cell density (late-exponential phase) resulted in more hG-CSF production compared with induction at lower cell density (early to mid-exponential phase). The constant feeding strategy that supported best hG-CSF production was applied to the scale-up production of hG-CSF in 30 L of fermentor. The maximum dry cell weight and hG-CSF concentration of 51.7 and 4.2 gxL(-1), respectively, was obtained
Array-based mutation detection of the BRACA genes using direct probe/target hybridization and single base extension methods
No full textArray-based mutation detection of BRCA1 using direct probe/target hybridization
No full textWe describe here an efficient micro array-based multiplex assay to detect Korean-specific mutations in breast cancer susceptibility gene BRCA1 using direct probe/target hybridization. Allele-specific oligonucleotides were covalently immobilized on an aldehyde-activated glass slide to prepare an oligonucleotide chip. From a wild-type sample, a two-step method was used to generate labeled multiplex polymerase chain reaction (PCR) amplification products of genomic regions containing the mutation sites. Amino allyl-dUTP, an amine-modified nucleotide, was incorporated during multiplex PCR amplifications and a monofunctional form of cyanine 3 dye was subsequently attached to the reactive amine group of the PCR products. Hybridization of the labeled PCR products to the oligonucleotide chip successfully identified all of the genotypes for the selected mutation sites. This work demonstrates that oligonucleotides chip-based analysis is a good candidate for efficient clinical testing for BRCA1 mutations when combined with the indirect strategy to prepare labeled target samples. (C) 2004 Elsevier Inc. All rights reserved
Sequential feeding of glucose and valerate in a fed-batch culture of Ralstonia eutropha for production of poly(hydroxybutyrate-co-hydroxyvalerate) with high 3-hydroxyvalerate fraction
No full textSeveral 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.This work was supported by Grant M1-9808-00-0042
from the Ministry of Science and Technology in Korea
(KOSEF)
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