ELLIPSOMETRIC STUDIES OF BIOLOGICAL MACROMOLECULES

L'éllipsométrie a été utilisée pour étudier les propriétés d'adhésion de collagène et fibrinogène sur une surface métallique (Cr). L'épaisseur et l'indice de réfraction des couches obtenues ont été étudiés en fonction du temps d'incubation et de la concentration moléculaire. La même méthode a été appliquée pour étudier aussi l'adhésion du bactériophage T7.Adsorption properties of collagen and fibrinogen on Cr metal surface has been studied by ellipsometry. The thickness and refractive index of the thin films have been determined in function of the incubation time and solute concentration. The same method has been also applied to investigate the adsorption of T7 bacteriophage

Assessment of the Effects of Various UV Sources on Inactivation and Photoproduct Induction in Phage T7 Dosimeter

The correlation between the biologically effective dose (BED) of a phage T7 biological dosimeter and the induction of cyclobutane pyrimidine dimers (CPD) and (6-4) photoproducts ((6-4)PD) in the phage DNA was determined using seven various UV sources. The BED is the inactivation rate of phage T7 expressed in HT7 units. The CPD and (6-4)PD were determined by lesion-specific monoclonal antibodies in an immunodot-blot assay. The various lamps induced these lesions at different rates; the relative induction ratios of CPD to (6-4)PD increased with increasing effective wavelength of irradiation source. The amount of total adducts per phage was compared to the BED of phage T7 dosimeter, representing the average number of UV lesions in phage. For UVC (200-280 nm radiation) and unfiltered TL01 the number of total adducts approximates the reading; however, UV sources having longer effective wavelengths produced fewer CPD and (6-4)PD. A possible explanation is that although the most relevant lesions by UVC are the CPD and (6-4)PD, at longer wavelengths other photoproducts can contribute to the lethal damage of phages. The results emphasize the need to study the biological effects of solar radiation because the lesions responsible for the lethal effect may be different from those produced by various UV sources