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Biochem Mol biol J
ISSN: 2471-8084
Volume 3, Issue 2
Metabolomics Conference 2017
August 29-30, 2017 Prague, Czech Republic
9
th
International Conference and Exhibition on
Metabolomics and Systems Biology
Notes:
Page 31
Modulation and resilience of the metabolome
of
Pseudomonas graminis
, a cloud bacterium,
facing H
2
O
2
atmospheric stress
Anne-Marie Delort
1,2
, Nolwenn Wirgot
1
, Marie Lagrée
1,2
, Mounir
Traïkia
1,2
, Isabelle Canet
1
, Martine Sancelme
1
, Cyril Jousse
1,2
and
Bernard Lyan
2
1
Université Clermont Auvergne, CNRS, France
2
Université Clermont Auvergne & I.N.R.A site de Theix, France
I
n cloud waters, microorganisms are metabolically active
although they are exposed to very strong stresses,
especially due to the presence of reactive oxygenated
species, including H
2
O
2
and radicals. In order to
understand how microorganisms can modulate their
metabolism facing H
2
O
2
stress, we have investigated by a
metabolomics approach the response of a
Pseudomonas
gramini
s strain, isolated from cloud waters, to hydrogen
peroxide exposure. For this purpose
P. graminis
cells
were incubated in microcosms containing artificial cloud
waters in the presence or absence of H
2
O
2
. Metabolites
were extracted at two time points (50 min and 24 h)
that were important regarding the evolution of ATP
cellular content and H
2
O
2
degradation over time. These
bacterial extracts were analysed by LC-MS and 1H-NMR
using the Metabolic Profiler® facility (Bruker). Metabolic
profiles were converted into matrices and statistical
analyses (PCA, PLS-DA) were performed; key markers
of this oxidative stress were identified by 2D NMR and
LC-MS-Orbitrap. At time 50 min, when H
2
O
2
was still
present in the incubations, the bacteria adapted and
modulated their metabolome facing this stress. The major
metabolic pathways of
Pseudomonas gramini
s (13b-3)
impacted by the presence of hydrogen peroxide were
the carbohydrate pathway, glutathione, energy, lipid and
amino-acid metabolisms. Unexpectedly, the concentration
of a few dipeptides containing mainly Ala, Val, Leu (Ile)
was also highly modified in the presence of H
2
O
2
.
These dipeptides are reported here for the first time as
biomarkers of oxidative stress. Interestingly, at time 24 h,
when H
2
O
2
has been completely biodegraded by the cells,
no more significant difference was observed between the
metabolites of exposed and non-exposed cells to H
2
O
2
.
This shows the resilience of this bacterium metabolome
after H
2
O
2
stress exposure. These results are discussed
in terms of impacts on cloud chemistry.
Biography
Anne-Marie Delort is a Senior Scientist at CNRS. She is working at Institute of
Chemistry of Clermont-Ferrand in France. In addition to a general background
in chemistry and molecular biology, her expertise covers Microbiology and
Metabolomics. She specifically studies microbial metabolism in relation with
the environment. She has been a pioneer in studying the microbial population
in clouds. Recent studies concern the adaptation of microorganisms to
atmospheric stresses and the role of microorganisms in atmospheric
chemistry and physics. This includes the transformation of organic matter,
interaction with oxidants and formation of ice nuclei and cloud condensation
nuclei (biosurfactants). Her group is part of MetaboHUB, the French national
infrastructure of excellence in metabolomics and fluxomics.
a-marie.delort@uca.frAnne-Marie Delort et al., Biochem Mol biol J, 3:2
DOI: 10.21767/2471-8084-C1-002