7 research outputs found
Media 1: Pulse bursts with a controllable number of pulses from a mode-locked Yb-doped all fiber laser system
Originally published in Optics Express on 24 March 2014 (oe-22-6-6699
Mirror-Image Thymidine Discriminates against Incorporation of Deoxyribonucleotide Triphosphate into DNA and Repairs Itself by DNA Polymerases
DNA
polymerases are known to recognize preferably d-nucleotides
over l-nucleotides during DNA synthesis. Here, we report
that several general DNA polymerases catalyze polymerization reactions
of nucleotides directed by the DNA template containing an l-thymidine (l-T). The results display that the 5′–3′
primer extension of natural nucleotides get to the end at chiral modification
site with Taq and Phanta Max DNA polymerases, but the primer extension
proceeds to the end of the template catalyzed by Deep Vent (exo<sup>–</sup>), Vent (exo<sup>–</sup>), and Therminator DNA
polymerases. Furthermore, templating l-nucleoside displays
a lag in the deoxyribonucleotide triphosphate (dNTP) incorporation
rates relative to natural template by kinetics analysis, and polymerase
chain reactions were inhibited with the DNA template containing two
or three consecutive l-Ts. Most interestingly, no single
base mutation or mismatch mixture corresponding to the location of l-T in the template was found, which is physiologically significant
because they provide a theoretical basis on the involvement of DNA
polymerase in the effective repair of l-T that may lead to
cytotoxicity
Media 1: Flexible operability and amplification of gray pulses
Originally published in Optics Letters on 15 July 2014 (ol-39-14-4116
Media 3: Different polarization dynamic states in a vector Yb-doped fiber laser
Originally published in Optics Express on 20 April 2015 (oe-23-8-10747
Effects of Conformational Alteration Induced by d‑/l‑Isonucleoside Incorporation in siRNA on Their Stability in Serum and Silencing Activity
We
report here that all of the d- or l-isonucleoside
(isoNA) modified siRNAs investigated showed the characteristic A-form
conformation in the circular dichroism (CD) spectra compared to native
siRNA. The d-isoNA modification had less influence on the
thermal stability of siRNAs, but all l-isoNA modification
displayed a significant tendency to decrease the thermal stability
of siRNA. It was also found that the stabilities of d-/l-isoNA modified siMek1 in serum were different and d-isoNA modification was more potent, i.e., increase of serum stability
of siRNA, than l-isoNA modification. When d-isoNA
incorporated at position 4 and position 5 at antisense strand of siMek1
showed obvious improvement on serum stability, however, l-isoNA incorporated at positions 11 and 12 at antisense strand and
position 9 at sense strand made the siMek1 duplex formed very unstable
in serum. The silencing activities of modified siMek1s with d-/l-isoNA at position 1 of antisense strand also dropped
dramatically; however, the modification at 3′-terminal of the
sense strand with d- or l-isoNA significantly enhanced
the silencing activity targeting the antisense strand as reporter
and minimized the passenger strand-specific off-target effect. IsoNA
modified in the seed area of siMek1, <b>siMek1 A04D</b> and <b>siMek1 A05L</b>, showed similar activity to the native one and
better target selectivity. In the case of modification at the position
near the cleavage area, it was found that d- or l-isoNA modified sense strand at position 8, 9, or 15 of siMek1 could
retain the silencing activities targeting the antisense strand as
reporter. Especially, both <b>siMek1 S15D</b> and <b>siMek1
S15L</b> showed good silencing activity and high target selectivity
compared to native siMek1. The effects of conformational alteration
of such isoNA modification of siRNA on their stability in serum and
silencing activity are discussed based on computer simulation. Systematic
investigation of the relationship between modified siRNA conformation
and their physical and biological properties should provide a useful
guideline for chemical modification and optimization of siRNA for
further clinical application
Media 1: Different polarization dynamic states in a vector Yb-doped fiber laser
Originally published in Optics Express on 20 April 2015 (oe-23-8-10747
Biological Properties of a 3′,3″-Bis-Peptide-siRNA Conjugate in Vitro and in Vivo
This study proposes an effective
melanoma small interfering RNA
(siRNA), named siMB3, which targets the mRNA of mutant BRAF protein.
We found that Bis-pep-siMB3, with peptide KALLAL-conjugated siMB3
at the 3′-termini of both strands, inhibited translation of
the target genes and expression of the related protein as effectively
as siMB3, but for substantially longer, and the conjugates could alleviate
off-target effects. Further studies on the mechanisms of action showed
that the stability of Bis-pep-siMB3 in fetal bovine serum improved
and the half-life period of Bis-pep-siMB3 was increased 21-fold over
that of siMB3. Peptide conjugation could improve the combination of
siRNA and cationic lipid vectors. Bis-pep-siMB3 is likely to reach
the lysosome earlier and stay longer, and appears to increase the
release of siRNA from the endosome. At the animal level, application
of Bis-pep-siMB3 showed good therapeutic potential, inhibiting the
growth of xenograft tumors in athymic mice slightly better than siMB3
and greatly prolonging the circulating time in vivo. Moreover, it
distributed widely in mice. These results show the promising potential
of Bis-pep-siRNA conjugates as therapeutic siRNAs for cancer treatment