Download PROJECT PROPOSAL for applicants for Ph.D. fellowships

PROJECT PROPOSAL
for applicants for Ph.D. fellowships
supervisor:
institution:
contact:
CV:
Bettina UGHYDSB, Ph.D.
Institute of Plant Biology
[email protected]
http://www.brc.hu/file/cv/plant_ughy_bettina_en.pdf
project title:
CYANOBACTERIAL CELL DIVISION
PROJECT SUMMARY
The cell proliferation is one of the most fundamental processes of all organisms. Cell division in
bacteria is initiated by a ring-like protein structure at midcell. The timing and positioning of the
formation of the so-called Z-ring is crucial for cell divisions. Living organisms often have to confront
with changing environment and they should adapt to different stress conditions. Bacterial cell
morphology and division mechanism may change in response to environmental cues. The question
is how the cell division factors control the division process in cyanobacteria, ancestors of plant
plastids, under different environmental conditions.
BACKGROUND OF THE STUDY
Cyanobacteria are oxygenic photosynthetic
bacteria that can be found in a wide range of
habitats, which includes freshwater, marine,
terrestrial
and
extreme
environments.
Cyanobacteria have appeared on the primordial
Earth over three billion years ago and these
photosynthetic microbes evolved an amazing
arsenal of biochemical pathways that exert
defence mechanisms and produce metabolites
unique to them. Their high capability to adapt to
the various environments may be related to
their long evolutionary history. Cyanobacteria
are believed to be the ancestor of higher plant
plastids; therefore, they are good model
organisms for investigation of photosynthetic
processes and chloroplast development. They
have high capability to adapt to changing
environments by activating various strategies.
Nowadays cyanobacteria are in the focus of
intensive research because of their potential
application in various fields of biotechnology.
Cyanobacteria are involved in various
applications that could help protecting the
environment and diminishing the destructive
effects of the industrial activities, moreover they
can be the source of various natural products
such as biofuel or biodegradable plastics.
Cyanobacteria could be a source of new
pharmaceutical compounds because they
produce secondary metabolites with unique
chemical structure. These bacteria also used as
dietary supplement and in production of
cosmetics. On the other hand toxin production
of cyanobacteria could pose health hazard for
humans and animals alike. Harmful algal and
cyanobacterial blooms can caused severe
problem both in marine and freshwater
environments. Contamination by other
organisms of the selected strains of
cyanobacteria cultured in large-scale for
consumption or for metabolite production could
also cause trouble. Therefore appropriate and
strict quality control is needed for safe growing
and applications of these organisms. For most
biotechnological applications production of high
cyanobacterial
biomass
is
needed.
Cyanobacteria reproduce by binary fission
(Figure 1). Cell division in bacteria is mediated
by a macromolecular machinery known as
divisome. The divisome formation is initiated by
polymerization of the FtsZ protein forming the
so-called Z-ring at the midcell. Several proteins
involved in prokaryotic cell division were
identified but the molecular mechanism of the
division ring formation and positioning is still not
fully elucidated. Correct positioning of the Z-ring
is crucial for the cells. Certain cyanobacteria
show nutrient-associated changes that included
arrest of cytokinesis along with cell elongation,
as well as asymmetric cell division once
proliferative conditions were resumed. Nutrient
limitation caused cell elongation of the
Synechococcus sp. PCC7942 cyanobacterial
cells. The detailed mechanism underlying the
position of the divisome in symmetric fission of
normal size cells as well as determination of the
sites of division of elongated cells need to be
elucidated in cyanobacteria. Also, the role and
interactions of the cell division and its
controlling proteins is not fully elucidated in
cyanobacteria.
RELEVANT RESEARCH IN THE HOST
LABORATORY
In the last few years our research was focused
on the role of phosphatidylglycerol (PG) in
cellular processes of cyanobacteria. We have
demonstrated by characterization of PGdeficient cyanobacterial mutant strains that this
phospholipid has important roles in the
structure and function of photosynthetic
complexes. Depletion of PG resulted in
morphological changes causing cell elongation
and arrested the cell division, suggesting its
further role in cyanobacterial cell division.
However, it is not known in detail how the lipid
composition of membranes affects the division
process and the function and interactions of
proteins involved in this process. It also unclear
how different environmental and stress
conditions influence the cell division processes
and how the participating proteins mediate cell
division in cyanobacteria under different
conditions. To this end, we are to investigate
the cell fission and the role of cell division
proteins in cyanobacteria under various
conditions
using
molecular
biological
biophysical and biochemical techniques.
Supported by the
TÁMOP 4.1.1.C -13/1/KONV.2014-0001
project
Dividing Synechococcus PCC7942 cyanobacterial cell, in
which the division ring is visualised by the signal of the
inserted GFP.
SPECIFIC AIMS
Green fluorescence protein (GFP) fusion
proteins will be introduced into cyanobacteria to
study cell division by monitoring their
localization during cell fission under different
conditions by confocal laser scanning
microscopy (CLSM). Co-immune precipitation
(co-IP) assays and Western blot hybridization
will be used to investigate the interactions
between the cell division proteins under
different growth conditions.
MATERIAL AND METHODS
 Basic molecular biology techniques such as
cloning, DNA isolation, plasmid isolation and
PCR.
 CLSM will be used to follow the localization of
the GFP signals.
 Protein isolation, co-IP experiments and
Western blot hybridization.
SUGGESTED READINGS
Miyagishima SY, et al.: Identification of cyanobacterial
cell division genes by comparative and mutational
analyses. Mol. Microbiol., 56(1):126-143(2005)
Laczko-Dobos H, et al.: Role of phosphatidylglycerol in
the function and assembly of photosystem II reaction
center, studied in a cdsA inactivated PAL mutant strain of
Synechocystis sp. PCC6803 that lacks phycobilsomes.
BBA, 1777:1184-1194(2008)
Bogos B, et al.: Phosphatidylglycerol depletion affects
photosystem II activity in Synechococcus sp. PCC7942
cells. Photosynth. Res., 103:19-30(2009)
Marbouty M, et al.: Characterization of the FtsZinteracting septal proteins SepF and Ftn6 in the
spherical-celled cyanobacterium Synechocystis strain
PCC 6803. J. Bacteriol., 191(19):6178-6185(2009)
Miyagishima SY: Mechanism of plastid division: from a
bacterium to an organelle. Plant Physiol., 155(4):15331544(2011)
Marbouty M, et al.: The cyanobacterial cell division factor
Ftn6 contains an N-terminal DnaD-like domain. BMC
Struct Biol., 9:54(2009)
Marbouty M, et al.: Characterization of the FtsZinteracting septal proteins SepF and Ftn6 in the
spherical-celled cyanoacterium Synechocystis strain PCC
6803. J Bacteriol., 191:6178-6185(2009)
Marbouty M, et al.: Characterization of the Synechocystis
strain PCC 6803 penicillin-binding proteins and
cytokinetic proteins FtsQ and FtsW and their network of
interactions with ZipN. J Bacteriol., 191:5123-5133(2009)
SNAPSHOTS FROM THE HOST LABORATORY
Significant publications
Sozer O, et al.: Proteins, glycerolipids and carotenoids in the functional photosystem II architecture. Front Biosci
(Landmark Ed), 16:619-643(2011)
Domonkos I, et al.: Carotenoids, versatile components of oxygenic photosynthesis. Prog Lipid Res., 52:539-561(2013)
Nagy G, et al.: Reversible membrane reorganizations during photosynthesis in vivo: revealed by small-angle neutron
scattering. Biochem J., 436:225-230(2011)
Nagy G, et al.: Chloroplast remodelling during state transitions in Chlamydomonas reinhardtii as revealed by noninvasive
techniques in vivo. PNAS 111:5042-5047(2014)
Representative recent research grants
”Role of phosphatidylglycerol in cyanobacterial cell fission” (OTKA-K 2010-2014)
”Structural and functional plasticity of thylakoid membranes” (OTKA-K 2015-2018)
Some of the latest students in the laboratory
Kóbori TO, ITC+Ph.D., 2011-2014; “Role of phosphatidylglycerol in cyanobacterial cell division”
Sarvanan GK, ITC, 2014-recent; “Role of phosphatidylglycerol in cyanobacterial cell division and electron transport
processes”
Supported by the
TÁMOP 4.1.1.C -13/1/KONV.2014-0001
project