Abstract: Objective To observe the changes of the outer cell wall in resting phase and during swelling process of conidia of Aspergillus fumigatus,and the distribution of fibronectin receptors on conidia surface.Methods After being harvested with 3.5～4.0μm steel filters,the conidia were resuspended in RPMI 1640+10%FBS medium.The specimens were observed by the scanning electron microscopy after incubation for 0,2,4,6 hours at 37℃ respectively.The same amount of conidia was resuspendesd in PBS buffer,and put the suspension on 50μg/ml fibronectin coated microtitre plate,after incubation for 3hrs at 37℃,the conidia were washed three times with PBS.Then rabbit antifibronectin antibody and fluorescein isothiocyanate(FITC)conjugated goat anti-rabbit immunoglob-ulin antibody were added,respectively.After digesting with trypsin,the conidia were washed again with PBS and examined by immuno-confocal microscopy.Results Acharacteristic echinulate pattern of protrusions was shown in the cell wall surface of resting conidia.During swelling process,the echinulate layer of swollen conidia was gradually disintegrated,and almost completely shed 4hr later.Then,a smooth cell wall layer covered by some strands of fib-rillar material was shown.Binding of fibronectin to the surface of conidia was revealed by immuno-confocal microscopy.FITC was homogeneously adhered to the protrusions on the conidial outer cell wall layer.Conclusion In resting phase the conidia of A.fumigatus express high levels of fibronectin receptors on their surface,they are ho-mogeneously distributed over the external echinulate layer of the conidia,and shed gradually during the swelling process.

Key words: Spores,fungal, Receptors,fibronectin, Aspergillus fumigatus