Page 185 - The Biochemistry of Inorganic Polyphosphates

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WU095/Kulaev
WU095-08
Algae 169
100 200
90
ΣPP
80 160 RNA
70
µM P PolyP (130 ml) −1 60 120 µM P RNA (130 ml) −1 PP2

50
80
40
30
20 40 PP4
PP1
10 PP5

0
3 6 10 16 20
Time (h)

Figure 8.27 Changes in the content of PolyP fractions and RNA during the growth of a culture
of Neurospora crassa (Chernysheva et al., 1971): PP 1 ,PP 2 ,PP 4 and PP 5 represent the PolyP(I),
PolyP(II), PolyP(IV) and PolyP(V) fractions, respectively.

was demonstrated by electron microscopic methods (Atkinson et al., 1974; Peverly
et al., 1978). By X-ray microanalysis, phosphorus-containing granules were observed in the
cytoplasm, vacuoles and chloroplasts of Scenedesmus quadricauda (Voˇr´ıˇsek and Zachleder,
1984). In Cosmarium, PolyP was revealed in cytoplasmic granules (Elgavish and Elgavish,
1980). PolyP was identified in the vacuoles of Ulva latuca, and this compartment was also
rich in Mg 2+ (Lundberg et al., 1989). The chain length of the PolyP in this organism was
determined to be ∼ 20 residues (Weich et al., 1989).
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A P NMR spectroscopic study of the living cells of Chlorella fusca allowed conclusions
concerning the localization and structural features of its particular PolyP. The signal of the
core PolyP groups of this organism had a broad width. This indicated that the PolyP may
be present in cell compartments under different chemical conditions, may have different
chain lengths cation complexations, and may also be subjected to rapid exchange processes
(Sianoudis et al., 1986). A high concentration of EDTA or adjustment of the pH to 12.9 led to
a partial shift of the core PolyP signal. Thus, at least some part of this signal originated from
PolyP located outside the cytoplasmic membrane, because this form was easily accessible
to environment changes (Sianoudis et al., 1986). These some workers also showed the
importance of divalent cations for structural organization of the PolyP in Chlorella fusca
but did not exclude the presence of monovalent complexed PolyP (Sianoudis et al., 1986).
Peverly et al. (1978) concluded that divalent cations played only a minor role in the synthesis
of vacuolar PolyP granules in Chlorella pyrenoidosa, while K was an essential component.
The alga Chlamydomonas reinhardtii contains cytoplasmic vacuoles that are often filled
with dense granules. Purified granules contained PolyP complexed with calcium and