Change of Surface Shape and Distribution of Fibronectin Receptors on Aspergillus fumigatus Conidia / 中华皮肤科杂志

ABSTRACT

Objective To observe the changes of the outer ce ll wall in resting phase and during sw elling process of conidia of Aspergillus fumigatus,and the distribution of fibronectin receptors on conidia surface.Methods After being harvested with 3.5～4.0?m steel filters,the conidia were resuspended in RPMI 1640+10%FBS medium.The specimens were observed by the scanning electron microscopy after incubation for 0,2,4,6hours a t37℃respectively.The same amount of conidia was resuspendesd in PBS buffer,and put the suspension on 50?g /ml fibronectin coated microtitre plate,after incubation for 3hrs at 37℃,t he conidia were washed three times wi th PBS.Then rabbit antifibronectin antibody and fluorescein isothiocyanate(FITC)conjugated goat anti-rabbit immunoglob-ulin antibody were added,respectiv ely.After digesting with trypsin,t he 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 coni dia.During swelling process,the ec hinulate layer of swollen conidia wa s gradually disintegrated,and almost complete ly shed 4hr later.Then,a smooth cell wall layer covered by some strands of fib-rillar material was shown.Binding o f fibronectin to the surface of conid ia was revealed by immuno-confocal m i-croscopy.FITC was homogeneously ad hered to the protrusions on the conid ial outer cell wall layer.Conclusion In resting phase the conidia of A.fumigatus express high levels of fibronectin r eceptors on their surface,they are h o-mogeneously distributed over the ex ternal echinulate layer of the conid ia,and shed gradually during the swe lling process.