Chick and mouse embryonic lung mesenchyme were incubated in vitro with an equimolar mixture of (12)C- and (15)N-labeled adenosine, guanosine, cytidine, and uridine, and trace amounts of the four tritiated ribonucleosides. This permits an unambiguous method for detecting transfer of macromolecular RNA from such a pre-incubated mesenchyme to responding lung epithelium across a Millipore filter, a...

A strategy of interfacial energy transfer upconversion is demonstrated through the use of a terbium (Tb(3+) ) dopant as energy donor or energy migrator in core-shell-structured nanocrystals. This mechanistic investigation presents a new pathway for photon upconversion, and, more importantly, contributes to the better control of energy transfer at the nanometer length scale.

We demonstrate plasmon-assisted energy transfer between fluorophores located at distances up to 7  μm on the top of a thin silver film. Thanks to the strong confinement and large propagation length of surface plasmon polaritons, the range of the energy transfer is almost 2 orders of magnitude larger than the values reported in the literature so far. The parameters driving the energy transfer ra...

Energy transfer within photosynthetic systems can display quantum effects such as delocalized excitonic transport. Recently, direct evidence of long-lived coherence has been experimentally demonstrated for the dynamics of the Fenna-Matthews-Olson (FMO) protein complex [Engel et al., Nature (London) 446, 782 (2007)]. However, the relevance of quantum dynamical processes to the exciton transfer e...

In established methods for analyzing ribozyme kinetics, radiolabeled RNA substrates are primarily used. Each data point requires the cumbersome sampling, gel electrophoretic separation, and quantitation of reaction products, apart from the continuous loss of substrate by radioactive decay. We have used stable, double fluorescent end-labeled RNA substrates. Fluorescence of one fluorophore is que...

In this work, we derive the well-established expression for the quantum amplitude associated with the resonance energy transfer (RET) process between a pair of molecules that are beyond wavefunction overlap. The novelty of this work is that the field of the mediating photon is described in terms of a spherical wave rather than a plane wave. The angular components of the field are constructed in...

Ultrafast electronic excitation transfer (EET) followed by structural and vibrational relaxation (VER) of the acceptor have been characterised using transient absorption and transient lens techniques.

Tertiary contacts are critical to stabilizing the folded conformations of structured RNAs. In some cases, these contacts have been shown to interact with positive cooperativity. Measuring the energetic coupling of tertiary contact formation is among the most basic physical characterizations of a structured RNA. With proper experimental design, single-molecule fluorescence resonance energy trans...

Messenger RNA Is the Carrier of Information Present in DNA 00 Ribosomes Are Workbenches for Protein Biosynthesis 00 Transfer RNA Acts as a Bilingual Translator Molecule 00 The Genetic Code Uses a Four-Letter Alphabet of Nucleotides 00 Codons in mRNA Are Three-Letter Words 00 Punctuation 00 Codon–Anticodon Interactions Permit Reading of mRNA 00 ‘‘Breaking’’ the Genetic Code 00 Mutations 00 Amino...

Evidence is presented that is interpreted as reflecting a codon-directed specific requirement for deacylated transfer RNA in reactions associated in sequence with the initiation of polyphenylalanine synthesis in a fractionated transfer system derived from rabbit reticulocytes. The ability of deacylated transfer RNA to participate in these early reactions, as measured by a shift in the optimum M...