Studies of nucleotide sequences in TMV-RNA. II - The action of spleen diesterase

Spleen diesterase action on polynucleotide and ribonucleic acid infectivit

Magnetic Resonance Water Proton Relaxation in Protein Solutions and Tissue: T1ρ Dispersion Characterization

BACKGROUND: Image contrast in clinical MRI is often determined by differences in tissue water proton relaxation behavior. However, many aspects of water proton relaxation in complex biological media, such as protein solutions and tissue are not well understood, perhaps due to the limited empirical data. PRINCIPAL FINDINGS: Water proton T(1), T(2), and T(1rho) of protein solutions and tissue were measured systematically under multiple conditions. Crosslinking or aggregation of protein decreased T(2) and T(1rho), but did not change high-field T(1). T(1rho) dispersion profiles were similar for crosslinked protein solutions, myocardial tissue, and cartilage, and exhibited power law behavior with T(1rho)(0) values that closely approximated T(2). The T(1rho) dispersion of mobile protein solutions was flat above 5 kHz, but showed a steep curve below 5 kHz that was sensitive to changes in pH. The T(1rho) dispersion of crosslinked BSA and cartilage in DMSO solvent closely resembled that of water solvent above 5 kHz but showed decreased dispersion below 5 kHz. CONCLUSIONS: Proton exchange is a minor pathway for tissue T(1) and T(1rho) relaxation above 5 kHz. Potential models for relaxation are discussed, however the same molecular mechanism appears to be responsible across 5 decades of frequencies from T(1rho) to T(1)

Alkaloids of solanum pseudocapsicum

The Solanaceae probably are the only family including species of very poisonous nature and others which are generally used as food plants. I need only mention those few names: Atropa belladonna (The deadly Nightshade), Hyoscyamus niger (The Henbane), and on the other hand Solanum lycopersicum (The Tomato) and Solanum tuberosum (.The Potato) . -Here I shall confine myself to the gem Solanum. It is now generally known that even Solanum tuberosum contains a toxic Alkaloid and we have learned how to avoid the danger of poisoning. A short survey of the history of the potato in Europe however will show us that that has not always been so.Solanocapsine and solanocapsidine, the alkaloids of Solanum pseudocapsicum have been investigated. Solanocapsine appears to have the empirical formula C₂₅H₄₀O₄N₂. On selenium dehydrogenation it yields methylcyclopentenophenanthrene (Diels' hydrocarbon); from this the fundamental similarity of its carbon skeleton to that of the sterols is inferred.Solanocapsidine is shown to have the empirical formula C₂₅H₄₂O₂N₂. In addition to a tertiary hydroxyl group it contains an amino- and an imino group. Two of these three groups are so situated in the molecule that they yield a condensation product with acetone. The second oxygen atom of solanocapsidine is probably present in the form of an ether linkage. Several derivatives and oxydation products have been obtained and analysed