16 research outputs found
Efficient Use of Photons in Photoredox/Enamine Dual Catalysis with a Peptide-Bridged Flavin–Amine Hybrid
An isoalloxazine (flavin) ring system and a secondary amine have been integrated through a short peptide linker with the aim of using photons as efficient as possible in photoredox/enamine dual catalysis. We herein report a peptide-bridged flavin-amine hybrid that can catalyze α-oxyamination of aldehydes with TEMPO under weak blue light irradiation to achieve an extremely high quantum yield of reaction (Φ = 0.80)
Determination of acid dissociation constants of flavin analogues by capillary zone electrophoresis
Acid dissociation constants (pKa) of 9 kinds of flavin analogues as molecular catalyst candidates were determined by CZE. Although some of the analogues are instable and degradable under the light-exposure or in alkaline aqueous solutions, the effective electrophoretic mobility of the flavin analogue of interest has been measured with the residual substance. The pKa values of the flavin analogues were analyzed through the changes in the effective electrophoretic mobility with varying pH of the separation buffer. One or two steps pKa values were determined by the analysis. One of the degraded species from the flavin analogues, lumichrome, was also detected in the CZE analysis, and its pKa values were also determined. While coexisting impurities generated over the storage conditions were found in some analogues, the pKa values of the target analogues were successfully determined with the help of the CZE separations. A pressure-assisted CZE was utilized for the determination or the estimation of the pKa values of such analogues as possessing carboxylic acid moiety
Ground-state properties of neutron-rich Mg isotopes
We analyze recently-measured total reaction cross sections for 24-38Mg
isotopes incident on 12C targets at 240 MeV/nucleon by using the folding model
and antisymmetrized molecular dynamics(AMD). The folding model well reproduces
the measured reaction cross sections, when the projectile densities are
evaluated by the deformed Woods-Saxon (def-WS) model with AMD deformation.
Matter radii of 24-38Mg are then deduced from the measured reaction cross
sections by fine-tuning the parameters of the def-WS model. The deduced matter
radii are largely enhanced by nuclear deformation. Fully-microscopic AMD
calculations with no free parameter well reproduce the deduced matter radii for
24-36Mg, but still considerably underestimate them for 37,38Mg. The large
matter radii suggest that 37,38Mg are candidates for deformed halo nucleus. AMD
also reproduces other existing measured ground-state properties (spin-parity,
total binding energy, and one-neutron separation energy) of Mg isotopes.
Neutron-number (N) dependence of deformation parameter is predicted by AMD.
Large deformation is seen from 31Mg with N = 19 to a drip-line nucleus 40Mg
with N = 28, indicating that both the N = 20 and 28 magicities disappear. N
dependence of neutron skin thickness is also predicted by AMD.Comment: 15 pages, 13 figures, to be published in Phys. Rev.
Deformation of Ne isotopes in the island-of-inversion region
The deformation of Ne isotopes in the island-of-inversion region is
determined by the double-folding model with the Melbourne -matrix and the
density calculated by the antisymmetrized molecular dynamics (AMD). The
double-folding model reproduces, with no adjustable parameter, the measured
reaction cross sections for the scattering of Ne from C at
240MeV/nucleon. The quadrupole deformation thus determined is around 0.4 in the
island-of-inversion region and Ne is a halo nuclei with large
deformation. We propose the Woods-Saxon model with a suitably chosen
parameterization set and the deformation given by the AMD calculation as a
convenient way of simulating the density calculated directly by the AMD. The
deformed Woods-Saxon model provides the density with the proper asymptotic
form. The pairing effect is investigated, and the importance of the angular
momentum projection for obtaining the large deformation in the
island-of-inversion region is pointed out.Comment: 19 pages, 16 figures, 6 table
Production of Recombinant Monoclonal Antibodies in the Egg White of Gene-Targeted Transgenic Chickens
Increased commercial demand for monoclonal antibodies (mAbs) has resulted in the urgent need to establish efficient production systems. We previously developed a transgenic chicken bioreactor system that effectively produced human cytokines in egg whites using genome-edited transgenic chickens. Here, we describe the application of this system to mAb production. The genes encoding the heavy and light chains of humanized anti-HER2 mAb, linked by a 2A peptide sequence, were integrated into the chicken ovalbumin gene locus using a CRISPR/Cas9 protocol. The knock-in hens produced a fully assembled humanized mAb in their eggs. The mAb expression level in the egg white was 1.4–1.9 mg/mL, as determined by ELISA. Furthermore, the antigen binding affinity of the anti-HER2 mAb obtained was estimated to be equal to that of the therapeutic anti-HER2 mAb (trastuzumab). In addition, antigen-specific binding by the egg white mAb was demonstrated by immunofluorescence against HER2-positive and -negative cells. These results indicate that the chicken bioreactor system can efficiently produce mAbs with antigen binding capacity and can serve as an alternative production system for commercial mAbs
Identification of homogeneously staining regions by G-banding and chromosome microdissection, and FISH marker selection using human Alu sequence primers in a scleractinian coral Coelastrea aspera Verrill, 1866 (Cnidaria)
Karyotype analysis was performed on the scleractinian coral Coelastrea aspera Verrill, 1866, commonly found along temperate coasts in Japan (30–35°N) and in coastal waters in the Indian and Pacific oceans. G-banding of C. aspera was successfully performed, although the banding pattern was not as clear as that in mammals. The karyogram clearly revealed that this coral had a homogeneously staining region (hsr) in chromosome 11. This hsr consisted of ribosomal RNA (rRNA) related genes, which was demonstrated by fluorescence in situ hybridization (FISH) with probes generated using 28S ribosomal DNA (rDNA) primers and those generated through chromosome microdissection. In addition, we conducted silver-stained nucleolus organizer region (Ag-NOR) analysis and found Ag depositions in the interphase nuclei but not on rRNA gene loci and hsr(s) in the mitotic stage. The hsr of this coral was observed in approximately 50% of the metaphase spreads analyzed. This may explain the diversity of coral rDNA based on the molecular study of sequence analysis. Furthermore, it was discovered that human telomere and Alu repeated sequences were present in this C. aspera. Probes derived from human Alu sequences are expected to play an important role in the classification of corals. Overall, our data can be of great value in discriminating among scleractinian coral species and understanding their genetics, including chromosomal evolution