Biology Reference
In-Depth Information
yeast genera (
Grillitsch et al., 2011; Ivashov et al., 2012
). Phosphatidylserine was also
detected in LD, and cardiolipin and phosphatidic acid were found at minor quantities.
Although the major FA in LD from
S. cerevisiae
,
P. pastoris
, and
Y. lipolytica
is
oleic acid (C18:1), the total FA composition can vary notably.
S. cerevisiae
LD con-
tain mainly unsaturated FA with nearly equal amounts of oleic acid (C18:1) and pal-
mitoleic acid (16:1) (
40% of total fatty acid, each) (
Czabany et al., 2008
). Minor
amounts of palmitic acid (C16:0) and stearic acid (C18:0) were detected.
P. pastoris
LD contain mono- as well as polyunsaturated FA (
Ivashov et al., 2012
). Oleic acid
(18:1), linoleic acid (18:2), linolenic acid (C18:3), and palmitic acid (C16:0) are the
major FA in these LD. The FA distribution in LD from
Y. lipolytica
is in sharp con-
trast to
S. cerevisiae
and
P. pastoris
(
Athenstaedt et al., 2006
). Oleic acid (18:1) is
also the most abundant FA of
Y. lipolytica
LD (50% of total FA), but palmitic acid
(C16:0) is ranked second with
22% of total FA followed by minor amounts of
C16:1, C18:0, and C18:2.
Lipidome data obtained by mass spectrometric analysis gave a detailed insight
into nonpolar lipid and phospholipid species (
Grillitsch et al., 2011
) present in
LD from
S. cerevisiae
. Since major FA of
S. cerevisiae
are C16 and C18, species
patterns are rather simple. The most abundant species of TG are 52:1; 52:2, 52:3,
and 54:2 containing one C16 and two C18 FA. These lipid species make up to
65% of total TG of LD. The remaining TG species contain two or three C16 FA,
either saturated or unsaturated. Species patterns of individual phospholipids vary sig-
nificantly. In phosphatidylethanolamine and phosphatidylcholine of LD, the 32:2
(C16:1/C16:1) species is highly enriched compared to the homogenate. Additionally,
the 34:2 species (C16:1/C18:1) is highly abundant in these phospholipid classes. In
phosphatidylcholine 32:2 and 34:2 occur at similar levels. In contrast, 34:1 is the
most abundant lipid species of phosphatidylinositol and phosphatidylserine. Two
fully saturated species, namely 34:0 (C16:0/C18:0) and 36:0 (C18:0/C18:0), are
found in phosphatidylserine from
S. cerevisiae
LD.
Ivashov et al. (2012)
demon-
strated that the species pattern of phospholipids from
S. cerevisiae
LD differs from
P. pastoris
where C36 and C34 species are the majority of all phospholipid classes.
Noteworthily, phosphatidylcholine and phosphatidylethanolamine occur as several
polyunsaturated species such as C36:2, C36:3, C36:4, and C36:5.
Differences in the lipid profiles of LD from different yeast genera largely reflect
their overall lipid biosynthetic capacity. As example, the lack of polyunsaturated FA
production in
S. cerevisiae
compared to
P. pastoris
(
Grillitsch et al., 2011; Ivashov
et al., 2012
) also results in genera specific FA patterns of LD. Consequently, LD pro-
vide a pool of lipid components which matches the requirements of the whole cell if
needed.
In summary, analytical methods described here contributed significantly to our
understanding of yeast LD biology. Isolation of pure LD by the protocol presented
here is the prerequisite for detailed analysis. Identification and quantification of
lipids and proteins from LD by -omics approaches are a major contribution to inves-
tigate molecular biological, cell biological, and regulatory aspects of LD biogenesis.
These approaches will enable researchers to develop an integrated picture of LD in
cellular processes in future research.
