Page 183 - The Biochemistry of Inorganic Polyphosphates

March 9, 2004
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WU095-08
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Algae 167
Table 8.5 PolyP content in resting spores and mycelia of a 24 h culture of Penicillium
chrysogenum under different conditions of growth (Kulaev et al., 1959), expressed as mg
of P per g of dry biomass.
Mycelia on Mycelia on
synthetic medium containing
PolyP fraction Extractant Spores medium maize extract
◦
PolyP(I) 1 % TCA, 0–4 C 4.90 0.09 1.07
PolyP(II) Saturated NaClO 4 2.18 1.75 1.01
solution, 0–4 C
◦
◦
PolyP(III) + PolyP(IV) 10 % HClO 4 , 100 C 0.44 8.18 1.96
+ PolyP(V)
Total PolyP — 7.52 10.02 4.04
Total P — 16.15 28.28 44.27

31
High-resolution PNMRspectroscopywasemployedtoinvestigatetheeffectsofgrowth
stage and environmental osmolarity on the changes in PolyP metabolism in intact Neu-
rospora crassa cells (Yang et al., 1993). The ratio of PolyP to P i in the vacuoles increased
from 2.4 to 13.5 in N. crassa as cells grew from the early logarithmic phase to the stationary
phase. Hypo-osmotic shock of N. crassa initiated growth-dependent changes, including
(i) rapid hydrolysis of PolyP with a concomitant increase in the concentration of the cy-
toplasmic phosphate, (ii) an increase in cytoplasmic pH, and (iii) an increase in vacuolar
pH. The early logarithmic-phase cells produced the most dramatic response, whereas the
stationary-phase cells appeared to be recalcitrant to the osmotic stress. Thus, 95 and 60 %
of the PolyP in the early- and mid-logarithmic-phase cells, respectively, disappeared in
response to hypoosmotic shock, but little or no hydrolysis of PolyP occurred in the station-
ary cells. The osmotic stress-induced PolyP hydrolysis and pH changes in the early- and
mid-logarithmic-phase cells were reversible, thus suggesting that these changes to relate to
environmental osmolarity (Yang et al., 1993).
One of the interesting features of PolyP metabolism in fungi is the interrelation between
the metabolism and antibiotic biosynthesis (Kulaev, 1986). It was demonstrated that in high-
productive strains, under intensive synthesis of antibiotics, the PolyP content was lower than
in low-productive strains at the same growth stage (Figure. 8.29). This fact indicated that
PolyP is probably utilized as an energy source in the processes of antibiotic biosynthesis,
or there is a competitive relationship between the biosynthetic pathways of antibiotics and
PolyP for the energy sources (Kulaev, 1986).

8.12 Algae

8.12.1 Localization and Forms in Cells

Being eukaryotes, algae contain PolyPs in different cell compartments. The intracellular
localization of PolyPs in volutine granules of Chlorella fusca and Chlorella pyrenoidosa