Atypical Song Reveals Spontaneously Developing Coordination between Multi-Modal Signals in Brown-Headed Cowbirds (Molothrus ater)

The courtship and dominance behavior of brown-headed cowbirds (Molothrus ater) consists of a multi-modal display, including song as well as postural and wing movements. The temporal sequences of the acoustic and the visual display are coordinated. In adult male cowbirds the largest wing movements of the display are synchronized with silent periods of song, but it is unknown how this coordination emerges during song development. Here we investigate how visual display features are coordinated with song by using atypical song sequence structure of isolation-reared male cowbirds. In birds with atypical song, all components of the visual display were highly similar to those of “normal” song displays, but their timing was slightly different. The number of maximal wing movement cycles of isolation-reared males was linked to the number of sound units in the song, and was therefore reduced during the abbreviated song types of isolates. These data indicate that young cowbirds do not need to be exposed to a model of the visual display during ontogeny and that there is synchronization with the temporal structure of song. A physiological link between respiratory and syringeal control of silent periods between sound units and wing movement cycles may be driving this synchronization.     

Genomanalytische Untersuchungen bei Kürbis (Cucurbita L.)

Ohne ZusammenfassungMit 19 Abbildungen     

Paired-ion high-performance liquid chromatographic assay for plasma choline

Choline was isolated from deproteinized plasma by cation-exchange chromatography. Isolated choline was directly converted to the 3,5-dinitrobenzoate derivative and was analyzed by paired-ion high-performance liquid chromatography with UV detection at 254 nm. An internal standard, 3-hydroxy-N,N,N-trimethylpropanaminium iodide was used for quantitation of plasma choline.Linearity was achieved from 1–500 nmole/ml with a reproducibility of ± 6%. Plasma choline concentrations below 1 nmole/ml could not be accurately measured while plasma choline concentrations in the μmole/ml range deviated from linearity.     

Effect of verapamil and nifedipine on the adhesion, migration and phagocytosis of human neutrophilic granulocytes

The calcium antagonists Verapamil and Nifedipin have a different effect on adherence, migration and phagocytosis of human neutrophilic granulocytes. Whereas Verapamil (10(-4) mol/1) will inhibit the leukocyte function, Nifedipin is ineffective. The leukocyte function cannot be expected to be impaired by using Nifedipin and Verapamil in therapeutic doses. The differences in efficiency and their possible causes are discussed.     

Effect of amrinone and trapidil on adherence, migration and phagocytic behavior of neutrophilic granulocytes of the human

Amrinone and trapidile belong to a group of positive inotropic and simultaneously vasodilating substances, whose effects are based on an inhibition of phosphodiesterase (PDE), thus enriching intracellular c-AMP. In neutrophilic granulocytes these PDE-antogonists will produce an inhibition of adherence and phagocytosis, whereas the migration was not affected. The lower leukocyte effective concentration of 10 mmol/l can be achieved by a therapeutical application, so that a slight inhibition of the leukocyte function has to be accounted for as a side effect.