microbiology, Vol 141, 2315-2322, Copyright © 1995 by Society for General Microbiology
Physarum polycephalum haemagglutinins: effect of nutrition on synthesis, and their possible role in nature
M Morita, E Minami, Z Lei and A Nishi
Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
The activity of haemagglutinins in plasmodia of Physarum polycephalum was
measured under different culture conditions. The activity was markedly
increased when the plasmodia were incubated in a non-nutrient salt medium.
During starvation, significant amounts of haemagglutinins were found in the
slime layer on the surface of the plasmodia. An increase in activity was
not observed in the presence of actinomycin D or cycloheximide. Under
starvation conditions, plasmodia are known to differentiate into either
sclerotia (spherules) or fruiting bodies. Acceleration of haemagglutinin
synthesis, however, was not always observed during spherulation and
fruiting-body formation. Attempts to detect endogenous glycoconjugates that
bind to the haemagglutinins were unsuccessful but we found that the
haemagglutinins could bind to acidic polysaccharides produced by
Escherichia coli K12. The bacterial glycoconjugates were purified and
partially characterized. They contained N-acetylhexosamine residues which
appeared to be important for binding with the haemagglutinins. It is
possible that the haemagglutinins play a physiological role in the
interaction with these organisms.
