Abstract:
Polyclonal antibodies prepared against the two glycoproteins (Mr
100 and 85 kDa) involved in recognition and attachment of the
mycoparasite, Piptocephalis virginiana, to its hosts, Mortierella pusilla and
Phascolomyces articulosus, susceptible and resistant, respectively, were
employed to localize the antigens at their cell surfaces. Indirect immunocytochemical
technique using secondary antibodies labelled with either
FITC or gold particles as probes, were used. FITC-Iabelled antibodies
revealed a discontinous pattern of fluorescence on the hyphae of
MortlerelLa pusilla and no fluorescence on the hyphae of Phascolomyces
articulosus. Intensity of fluorescence was high in the germinating spores
of both the fungi. Fluoresence could be observed on P. articulosus hyphae
pretreated with a commercial proteinase. Fluorescence was not observed
on either hyphae or germinating spores of the nonhost M0 r tie re11 a
ca ndelabrum and the mycoparasite P. virginiana. Antibodies labelled with
gold conjugate showed a different pattern of antigen localization on the
hyphal walls of the susceptible and resistant hosts. Patches of gold
particles were observed allover the whole cell wall of the susceptible host
but only on the inner cell wall layer of the resistant host. Cell wall
fragments of the susceptible host but not those of the resistant host,
previously incubated with the antibodies inhibited attachment of the
mycoparasite. Implications of preferential localization of the antigen in the
resistant host and its absence in the nonhost are described.
