2 research outputs found
The Role of Phospholipid Headgroup Composition and Trehalose in the Desiccation Tolerance of <i>Caenorhabditis elegans</i>
Anhydrobiotic organisms have the
remarkable ability to lose extensive
amounts of body water and survive in an ametabolic state. Distributed
to various taxa of life, these organisms have developed strategies
to efficiently protect their cell membranes and proteins against extreme
water loss. Recently, we showed that the dauer larva of the nematode <i>Caenorhabditis elegans</i> is anhydrobiotic and accumulates
high amounts of trehalose during preparation to harsh desiccation
(preconditioning). Here, we have used this genetic model to study
the biophysical manifestations of anhydrobiosis and show that, in
addition to trehalose accumulation, dauer larvae dramatically reduce
their phosphatidylcholine (PC) content. The chemical composition of
the phospholipids (PLs) has key consequences not only for their interaction
with trehalose, as we demonstrate with Langmuir–Blodgett monolayers,
but also, the kinetic response of PLs to hydration transients is strongly
influenced as evidenced by time-resolved FTIR spectroscopy. PLs from
preconditioned larvae with reduced PC content exhibit a higher trehalose
affinity, a stronger hydration-induced gain in acyl chain free volume,
and a wider spread of structural relaxation rates of their lyotropic
transitions and sub-headgroup H-bond interactions. The different hydration
properties of PC and phosphatidylethanolamine (PE) headgroups are
crucial for the hydration-dependent rearrangement of the trehalose-mediated
H-bond network. As a consequence, the compressibility modulus of PLs
from preconditioned larvae is about 2.6-fold smaller than that from
non-preconditioned ones. Thus, the biological relevance of reducing
the PC:PE ratio by PL headgroup adaptation should be the preservation
of plasma membrane integrity by relieving mechanical strain from desiccated
trehalose-containing cells during fast rehydration