48
EDWARD C. CANTINO AND JAMES S. LOVETT
machinery for making this potential energy available ; and (c) a transducing device whereby it is passed on to its flagellum and thus translated
into energy of motion. What can be said regarding these conclusions?
(a) What are these potential pools of chemical energy? Results from
electron microscopy suggested (vide supra), and chemical analyses
revealed (vide infra) that the spore is well supplied with a sizeable
amount of lipid and protein (Lovett and Cantino, 1960b; McCurdy and
Cantino, 1960), as well as a pool of a soluble polysaccharide composed
solely of glucose (Cantino and Goldstein, 1961). A priori, one or all could
be the major source of supply. However, when spores which have been
swimming for some hours are made to settle down and die, they can be
seen, microscopically, to gradually disintegrate as if by slow autolysis
(Cantino and Hyatt, 1953a). Under these conditions, the refractile
granules attached to the mitochondrion remain, apparently as intact and
numerous as they were before, while all else disappears. On this basis,
we might guess that lipid is not used in quantity by the spore, and that
it is not its major source for energy supply. Assuming further that the
spore cannot well afford to deplete itself of its supply of protein merely
for want of energy—an emotional argument perhaps—the finger points
at carbohydrate. Peripheral arguments in its favour follow.
(b) What enzymatic machinery is employed for utilization of the
energy pool? The endogenous formation of considerable quantities of
lactic acid by a spore (ca. 0-25^Mxmg dry wt.^xh
- 1 ; Cantino and
Lovett, 1960) is consistent with the thought that polysaccharide may be
an important, readily available pool for energy production. The
metabolism of this pool has not been followed in the spore during its
active, swimming stage in water ; but it is worth noting that later on in
ontogeny (Cantino and Goldstein, 1961), release of lactic acid is related,
mole for mole, to utilization of internal polysaccharide. Furthermore,
the very high specific activity (Lovett and Cantino, 1960b) of glucose-6phosphate and 6-phosphogluconate dehydrogenases in the spore—a
value greater than that found at any time during the exponential
growth of Blastocladiella
(Lovett and Cantino, 1960b; Goldstein and
Cantino, 1962)—suggests that the hexose monophosphate shunt could
be one route for disposition of the polysaccharide. Bearing also on this
question is the fact that exogenous glucose does not increase the
respiration of the spore (Cantino and Lovett, 1960; McCurdy and
Cantino, 1960), nor does it increase the endogenous output of lactic acid
(Cantino and Lovett, 1960), even though glucose is consumed (ca.
1-0 μ,Μ χ mg
-1 χ h
- 1 ). This suggests that the polysaccharide, with its
reservoir of built-in glycosidic bonds, is perhaps the preferred source of
supply of phosphorylated hexose units for the 'zwischenfermemV.
(c) What transducing device produces flagellar activity? If the
EDWARD C. CANTINO AND JAMES S. LOVETT
machinery for making this potential energy available ; and (c) a transducing device whereby it is passed on to its flagellum and thus translated
into energy of motion. What can be said regarding these conclusions?
(a) What are these potential pools of chemical energy? Results from
electron microscopy suggested (vide supra), and chemical analyses
revealed (vide infra) that the spore is well supplied with a sizeable
amount of lipid and protein (Lovett and Cantino, 1960b; McCurdy and
Cantino, 1960), as well as a pool of a soluble polysaccharide composed
solely of glucose (Cantino and Goldstein, 1961). A priori, one or all could
be the major source of supply. However, when spores which have been
swimming for some hours are made to settle down and die, they can be
seen, microscopically, to gradually disintegrate as if by slow autolysis
(Cantino and Hyatt, 1953a). Under these conditions, the refractile
granules attached to the mitochondrion remain, apparently as intact and
numerous as they were before, while all else disappears. On this basis,
we might guess that lipid is not used in quantity by the spore, and that
it is not its major source for energy supply. Assuming further that the
spore cannot well afford to deplete itself of its supply of protein merely
for want of energy—an emotional argument perhaps—the finger points
at carbohydrate. Peripheral arguments in its favour follow.
(b) What enzymatic machinery is employed for utilization of the
energy pool? The endogenous formation of considerable quantities of
lactic acid by a spore (ca. 0-25^Mxmg dry wt.^xh
- 1 ; Cantino and
Lovett, 1960) is consistent with the thought that polysaccharide may be
an important, readily available pool for energy production. The
metabolism of this pool has not been followed in the spore during its
active, swimming stage in water ; but it is worth noting that later on in
ontogeny (Cantino and Goldstein, 1961), release of lactic acid is related,
mole for mole, to utilization of internal polysaccharide. Furthermore,
the very high specific activity (Lovett and Cantino, 1960b) of glucose-6phosphate and 6-phosphogluconate dehydrogenases in the spore—a
value greater than that found at any time during the exponential
growth of Blastocladiella
(Lovett and Cantino, 1960b; Goldstein and
Cantino, 1962)—suggests that the hexose monophosphate shunt could
be one route for disposition of the polysaccharide. Bearing also on this
question is the fact that exogenous glucose does not increase the
respiration of the spore (Cantino and Lovett, 1960; McCurdy and
Cantino, 1960), nor does it increase the endogenous output of lactic acid
(Cantino and Lovett, 1960), even though glucose is consumed (ca.
1-0 μ,Μ χ mg
-1 χ h
- 1 ). This suggests that the polysaccharide, with its
reservoir of built-in glycosidic bonds, is perhaps the preferred source of
supply of phosphorylated hexose units for the 'zwischenfermemV.
(c) What transducing device produces flagellar activity? If the