Carboxylate anion diminishes chloride transport through a synthetic, self-assembled transmembrane pore.

Six amphiphilic heptapeptides with the structure (C18H37)2NCOCH2OCH2CO-(Gly)3-Pro-(Gly)n-(Glx)-(Gly)m-O(CH2)6CH3, in which Glx represents glutamic acid or its benzyl ester and n+m=2, have been studied. In addition, the glutamate residue in the GGGPGGE sequence was esterified by fluorescent 1-pyrenemethanol. These compounds insert into phospholipid bilayers and form anion-conducting pores.

Mass spectral characterization of fatty acid amides from alfalfa trichomes and their deterrence against the potato leafhopper.

A homologous series of N-(3-methylbutyl)amides of normal saturated C14, C15, C16, C17 and C18 fatty acids were identified as major components of glandular trichome extracts from Medicago sativa G98A, an alfalfa genotype resistant to the potato leafhopper, Empoasca fabae. A second homologous series of N-(2-methylpropyl)amides of C14 through C18 normal fatty acids were minor components. Saturated free fatty acids C12, C13, C14, C15, C16, C17 and C18 were present in trace amounts, as was the N-(3-methylbutyl)amide of linoleic acid (C18:2).

Bioactivity of lipophilic metabolites from glandular trichomes of Medicago sativa against the potato leafhopper.

Medicago sativa cv. G98A is highly resistant to the potato leafhopper, Empoascafabae. Glandular trichome extracts from G98A were fractionated using flash chromatography and tested for settling deterrency against the potato leafhopper.

Glandular trichome extracts from Medicago sativa deter settling by the potato leafhopper Empoasca fabae.

Extracts of glandular trichomes from Medicago sativa were tested for their ability to disrupt the settling behavior of the potato leafhopper, Empoasca fabae. Erect and procumbent glandular trichomes were mechanically isolated from stem sections of resistant genotype "G98A," and nonglandular trichomes were collected from susceptible cultivar "Ranger." Isolated trichomes were extracted with chloroform, acetone, and ethanol, and the resulting crude extracts were applied to the surface of a sachet containing an artificial diet.

Geographic distribution of three alkaloid chemotypes of Croton lechleri.

Three known alkaloids, isoboldine (2), norisoboldine (1), and magnoflorine (8), have been isolated for the first time from Croton lechleri, a source of the wound healing latex "sangre de grado". An HPLC system was developed, and a large number of latex and leaf samples of C. lechleri from 22 sites in northern Peru and Ecuador were analyzed to gain an understanding of the natural variation in alkaloid content for the species.