Page 77 - The Biochemistry of Inorganic Polyphosphates

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A part of the volutin granules was found in the cells of fungi and algae in vacuoles.
The presence of PolyP granules in vacuoles was confirmed by cytochemistry and X-ray
dispersion microanalysis in algae (Atkinson et al., 1974; Peverly et al., 1978; Adamec
et al., 1979; Voˇr´ıˇsek and Zachleder, 1984), and yeast (Voˇr´ıˇsek et al., 1982). Indge (Indge,
1968a,b,c) was the first to indicate the presence of PolyPs in isolated yeast vacuoles. Since
the work of Matile and his associates (Matile, 1978; Urech et al., 1978; D¨urr et al., 1979;
Wiemkenetal.,1979),whichexaminedisolatedvacuolesandusedthemethodofdifferential
extraction of cell pools, an opinion has been formed in the literature that nearly all of the
PolyPs of yeast cells are located in these organelles. This opinion was supported by the
investigation of a vacuole-defective yeast mutant, where no ‘NMR-visible’ PolyPs were
found (Shirahama et al., 1996). However, it should be noted that the PolyP content in
vacuoles strongly depends on the cultivation conditions. Data on the quantity of PolyPs in
yeast vacuoles are the most numerous, but are still quite contradictory, since the authors used
different strains and cultivation conditions. When Saccharomyces cerevisiae are grown on a
poor mineral medium with arginine as the only nitrogen source and the culture growth rate
is low, vacuoles may contain the major part of the yeast-cell PolyP pool (Wiemken et al.,
1979). The amount of PolyPs in yeast vacuoles sharply increases when this microorganism
accumulates metal cations. S. carlsbergensis vacuoles accumulated seven times more PolyP
than the cytosol under incubation with phosphate, glucose and K , and ten times more
+
PolyP with Mn 2+ (Lichko et al., 1982). Under other growth conditions, the vacuolar PolyP
pool in S. cerevisiae was significantly lower. The vacuoles of S. cerevisiae growing on
the ‘Reader medium’ contained nearly 15 % of the total amount of PolyPs in the cell
(Trilisenko et al., 2002). The vacuoles of Candida utilis contained no more than 30 % of the
total amount of PolyPs in the cell depending on the rate of culture growth and the nitrogen
source in the medium (Nunez and Callieri, 1989). The vacuoles contained PolyPs of short
chain lengths. These were determined to be ∼ 5 and 15–25 phosphate residues (Wiemken
et al., 1979). Later, this evaluation was confirmed by Trilisenko and co-workers (Trilisenko
et al., 2002). From an NMR spectroscopic study of the two PolyP fractions obtained from
isolated vacuoles of S. cerevisiae, it was shown that these organelles contain two fractions
of PolyPs: 5 ± 5 and 20 ± 2 phosphate residues. PolyPs were also found in the vacuoles of
Neurospora crassa (Cramer et al., 1980; Cramer and Davis, 1984) and Dunaliella salina
(Pick and Weiss, 1991). With regard to the role of vacuoles as the main compartment of
reserve compounds in eukaryotic microorganisms, it can be expected that other fungi, yeast
and algae have a vacuolar pool of PolyPs.
The vesicles of endoplasmic reticulum of yeast cells contain PolyPs and also a specific
system of their biosynthesis related to glycoproteins (Shabalin et al., 1979, 1985).
The cells of protozoa (Docampo and Moreno, 2001; Ruiz et al., 2001a; Rodriguez et
al., 2002a,b) and the alga Chlamydomonas reinhardtii (Ruiz et al., 2001b) possess specific
PolyP and Ca 2+ storage organelles–acidocalcisomes–which are similar to vacuoles in some
properties. These organelles possess PolyPs with chain lengths of 3, 50 and 700–800 phos-
phate residues. The latter high polymeric PolyPs were observed in small amounts. PolyPs
were also found in the lysosomes of human fibroblasts (Pisoni and Lindley, 1992).
PolyP complexes with poly-β-hydroxybutyrate, similar to those in bacteria, were iden-
tified in eukaryotic membranes, including animal cells (Reush, 1989, 1999a, 2000).
PolyPs with short chain lengths of 14 phosphate residues were found in yeast mitochon-
dria by using 31 P NMR spectroscopy. This PolyP makes up to 10 % of the total content