6Scientific Technical Services, University of Barcelona, 08028 Barcelona, Spain
Background: Cupressaceae is a family of plants resistant to airborne contamination and its pollen is the main cause of winter allergic respiratory diseases, especially in North America, Japan and Mediterranean countries. Recently, a major allergen from Cupressus arizonica pollen grains, Cup a 3, was cloned and expressed.
Objective: To study the effects of air pollution on the expression of Cup a 3, a thaumatin-like protein, in C. arizonica pollen grains using a combination of transmission electron microscopy and immunocytochemical techniques.
Methods: Observations were made in mature and hydrated C. arizonica pollen grains from various regions in Spain with different degrees of air pollution. Specimens were fixed using freezing protocols and ultrathin sections were incubated with anti-rCup a 3 rabbit polyclonal antibodies.
Results: Labelling of Cup a 3 was detected in mature and hydrated C. arizonica pollen grains. It was more intense in pollen from polluted air regions, and abundant gold particles were observed as they were released through the pollen grain walls. Moreover, gold particles remained abundant in the pollen cytoplasm. The labelling was noticeably lower in pollen grains from unpolluted air regions.
Conclusions: Cup a 3 is present in the cytoplasm and walls of cypress pollen grains during air-dispersion and hydration stages. The abundance of Cup a 3 in pollen grains under polluted air conditions indicates that these cypresses intensify their activity as a defence from environmental pollution, thus strengthening their allergenicity.
Supported by a grant CGL2006-15103-C04-01 from the Department of Education and Science of Spain.