Factorized Electron-Nuclear Dynamics with an Effective Complex Potential.

We present a quantum dynamics approach for molecular systems based on wave function factorization into components describing the light and heavy particles, such as electrons and nuclei. The dynamics of the nuclear subsystem can be viewed as motion of the trajectories defined in the nuclear subspace, evolving according to the average nuclear momentum of the full wave function. The probability density flow between the nuclear and electronic subsystems is facilitated by the imaginary potential, derived to ensure a physically meaningful normalization of the electronic wave function for each configuration of the nuclei, and conservation of the probability density associated with each trajectory in the Lagrangian frame of reference.

Synthesis of gamma-glutamyldopamine and other peptidoamines in the nervous system of Aplysia californica.

The synthesis of a series of gamma-glutamyl amines (gamma-Glu-amines), including gamma-Glu-dopamine, gamma-Glu-5-hydroxytryptamine, gamma-Glu-octopamine, gamma-Glu-tryptamine, gamma-Glu-tyramine, and gamma-Glu-phenylethylamine, by nervous tissue of the marine mollusc Aplysia californica is described. After ganglia were incubated in vitro with 14C-amines, the unchanged amine and a new 14C-labeled product, identified as the gamma-Glu conjugate of the amine, were isolated from the tissue extracts. Identification was made by comparing the chromatographic properties (HPLC, TLC, and LC) of the isolated conjugates with chemically synthesized gamma-Glu-amines before and after acid hydrolysis.

Synthesis of the novel dipeptide beta-aspartylglycine by Aplysia ganglia.

Isolated ganglia from Aplysia californica rapidly took up [14C]glycine or [14C]aspartate from a sea-water medium. Approximately 20% of the tissue radioactivity was recovered in the peptides beta-aspartylglycine and glutathione after incubation with [14C]glycine. Compared with other individual cells isolated from the abdominal ganglion, the glycine-containing white cells (R3-R14) incorporated less [14C]glycine into beta-aspartylglycine, but similar amounts into glutathione.

Identification of an acidic dipeptide, beta-aspartylglycine, in the CNS of Aplysia.

A novel dipeptide, beta-aspartylglycine (beta-DG), has been isolated from tissues of the marine gastropod mollusc Aplysia californica. This compound was detected only in Aplysia and not in other molluscs, such as Helix or Mercenaria, or in lobster or frog. Among the Aplysia tissues, the highest levels of beta-DG were in nervous tissue and in the reproductive tract.