This paper reports the first biochemical characterisation of
Tuber borchii mycelial strain ATCC 96540, grown in liquid media
containing either glucose, fructose or sucrose. A new biochemical method,
based on the estimation of total protein content, was
developed for determining the amount of mycelium growth. This method is
more
sensitive than other methods, allowing growth to
be monitored in the lag phase and when small amounts of mycelium are grown
on a solid medium. Mycelium of T. borchii utilizes
glucose and fructose as carbohydrate sources but grows poorly if at all
on
sucrose. In these experiments the functional state of the
mycelium was evaluated by determining the activity of enzymes of the
glycolytic and pentose phosphate pathways which are
involved in producing energy and in supplying reducing power through the
formation of reduced pyridine coenzymes. The
biochemical data on mycelium growth were supported by observations on
ultrastructural morphology which revealed the different
steps in hyphal depletion during ageing. In addition, the monitoring of
alanine content of the liquid media during mycelial growth
indicated that there was an increasing loss of alanine from their cytoplasm
as hyphae aged. The development of this procedure
makes it possible to identify the conditions under which T. borchii
is able to synthesize a mycorrhiza with a compatible host.