Structural and biochemical study of the effects of carbon monoxide on treeand grass pollen: labelling CO with O-18

Tree (birch) and grass (cockfoot) pollen samples have been exposed to an at mosphere enriched with (CO)-O-18 at doses ranging from 0.01 to 5% (v/v) for 48 h at room temperature. With the birch pollen samples (which were collec ted from the trees by us), these treatments have produced significant alter ations of the amount of assayed water soluble proteins and of the nature an d allergenic character of these proteins. The results were less clear with the (commercially purchased) cockfoot pollen, probably because the sampling and storage conditions by the seller were not optimal. With both birch and cockfoot pollens, the (CO)-O-18 treatment did not result in any visible st ereostructural alteration nor in any significant fixation of O-18-labelled CO in the pollen grains (at the sensitivity of the method), even with the h ighest dose of (CO)-O-18 used (5%). Our data are consistent with the idea t hat air pollutants such as CO can alter the availability and the nature of pollen allergens, a result which we believe to be important in the context of the relationship between allergy and pollution. From the methodological point of view, this study has also shown that the SIMS method was appropria te for using the stable isotope O-18 for the labelling and the analytical i maging of oxygen with no risk of interference by other substances.