Biomedical subjects

W I Gruszecki

Publications and source records attributed to W I Gruszecki.

20 records · Page 2Linked to original sources

PubMed1990

Orientation of xanthophylls in phosphatidylcholine multibilayers.

Oriented multibilayers of dimyristoyl phosphatidylcholine (DMPC) modified with violaxanthin or zeaxanthin were examined by X-ray diffractometry and linear dichroism. It appears that pigment molecules and the normal to the bilayer plane form an angle of 24-25 degrees. It was also observed that rather small concentrations of added xanthophylls (molar fraction up to 3%) increase the pigmented bilayer thickness by a value of about 2 A as compared with that of the pure DMPC bilayer. The observed nonzero linear dichroism at normal incidence of light suggests the possibility of nonhomogeneous orientation of transition dipoles in the plane of the bilayer.

Carotenoids↗

PubMedDate not supplied

Qualitative changes in the fluorescence spectra of intact pea leaves after photoinhibition.

In high light (1400 W m-2) treated, intact pea leaves, a decrease in the ratio of fluorescence emission at 685 to 730 nm and an increase in fluorescence intensity between 500 and 600 nm were observed. Furthermore, photoacoustically monitored heat emission increased slightly, and O2 evolution decreased significantly. These findings are interpreted as effects of a photoprotective mechanism separating the carotenoid pool from the chlorophylls. This is supported by fluorescence excitation measurements and the results of a study on the reversibility of the process.

Carotenoids↗