34 research outputs found
Synthetic polyamines stimulate in vitro transcription by T7 RNA polymerase.
Get PDFThe influence of nine synthetic polyamines on in vitro transcription with T7 RNA polymerase has been studied. The compounds used were linear or macrocyclic tetra- and hexaamine, varying in their size, shape and number of protonated groups. Their effect was tested on different types of templates, all presenting the T7 RNA promoter in a double-stranded form followed by sequences encoding short transcripts (25 to 35-mers) either on single- or double-stranded synthetic oligodeoxyribonucleotides. All polyamines used stimulate transcription of both types of templates at levels dependent on their size, shape, protonation degree, and concentration. For each compound, an optimal concentration could be defined; above this concentration, transcription inhibition occurred. Highest stimulation (up to 12-fold) was obtained by the largest cyclic compound called [38]N6C10.comparative studyjournal articleresearch support, non-u.s. gov't1994 Jul 25importe
Self-assembly of supramolecular triarylamine nanowires in mesoporous silica and biocompatible electrodes thereof
Get PDFBiocompatible silica-based mesoporous materials, which present high surface areas combined with uniform distribution of nanopores, can be organized in functional nanopatterns for a number of applications. However, silica is by essence an electrically insulating material which precludes applications for electro-chemical devices. The formation of hybrid electroactive silica nanostructures is thus expected to be of great interest for the design of biocompatible conducting materials such as bioelectrodes. Here we show that we can grow supramolecular stacks of triarylamine molecules in the confined space of oriented mesopores of a silica nanolayer covering a gold electrode. This addressable bottom-up construction is triggered from solution simply by light irradiation. The resulting self-assembled nanowires act as highly conducting electronic pathways crossing the silica layer. They allow very efficient charge transfer from the redox species in solution to the gold surface. We demonstrate the potential of these hybrid constitutional materials by implementing them as biocathodes and by measuring laccase activity that reduces dioxygen to produce water
Stable tumor vessel normalization with pO2 increase and endothelial PTEN activation by inositol trispyrophosphate brings novel tumor treatment
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The Utilization of Persistent H-Bonding Motifs in the Self-Assembly of Supramolecular Architectures
No full textConstitutional Adaptation of Dynamic Polymers: Hydrophobically Driven Sequence Selection in Dynamic Covalent Polyacylhydrazones
Full text linkThermoresponsive Dynamers: Thermally Induced, Reversible Chain Elongation of Amphiphilic Poly(acylhydrazones)
Full text linkConstitutional Adaptation of Dynamic Polymers: Hydrophobically Driven Sequence Selection in Dynamic Covalent Polyacylhydrazones
No full textNonlinear Kinetic Behavior in Constitutional Dynamic Reaction Networks
No full textCreating synthetic chemical systems
which emulate the complexity
observed in cells relies on exploiting chemical networks exhibiting
nonlinear kinetic behavior. While control over reaction complexity
using synthetic gene regulatory networks and DNA nanotechnology has
developed greatly, little control exists over small molecule reaction
networks. Toward this goal, we demonstrate a general framework for
inducing nonlinear kinetic behavior in dynamic chemical networks based
on molecules containing reversible chemical bonds. Specifically, this
strategy relies on constituent species with differing thermodynamic
stabilities that readily exchange components at rates that are faster
than their formation rates. Such nonlinear networks (NLN) readily
lead to sigmoidal kinetic profiles as a function of the relative thermodynamic
stabilities of the constituent species. Furthermore, this behavior
could be readily extended to more complex mixtures while maintaining
nonlinearity. The generality of this method opens the possibility
to generate nonlinear networks using a broad range of small molecule
structures
