3649-08 IICB.indd - Faculty of Biological Sciences - University of ...

Dave G. Adams
BSc (Liverpool);
PhD (Liverpool);
Lecturer in Microbiology, University of Leeds (1985 – 1995);
Senior Lecturer in Microbiology, University of Leeds (1995 - )
Contact: d.g.adams@leeds.ac.uk
Cyanobacteria: gliding motility,
plant symbiosis and bloom formation
My research interests encompass many
aspects of cyanobacteria and include
studies on the mechanism of gliding
motility, the formation of cyanobacteriaplant
symbioses and the prevention of
toxic cyanobacterial bloom formation.
Cyanobacteria are the largest group of
nitrogen-fixing bacteria on earth. Many
are filamentous and develop several
cell and filament types, including
the heterocyst (Figure 1), which is
specialised for nitrogen fixation,
and filaments known as hormogonia
which are motile by gliding and which
serve both as a means of dispersal
and as the infective agents in plantcyanobacteria
symbioses.
The mechanism of cyanobacterial
gliding motility is unknown. Beneath
the outer membrane of motile
cyanobacteria we have identified arrays
of parallel protein fibrils (Figure 2)
that we believe act as novel molecular
motors that provide the motive
force for gliding. To determine the
mechanism of gliding we are taking two
approaches. In the first we are isolating
and characterising the fibrils and fibril
structural proteins in wild-type and
mutant cyanobacteria. In the second
we hope to visualise motor function by
using Atomic Force Microscopy of live,
immobilised cyanobacteria.
Figure 2
As a model for our studies on symbiosis
we use the association between
cyanobacteria and the liverwort
Blasia. We are currently examining
the importance of chemotaxis to
the establishment of symbiosis by
using insertional mutagenesis of
genes involved in the formation and
function of pili which are external
protein fibres thought to be involved
in motility, adhesion and chemotaxis
of cyanobacterial hormogonia, all of
which are crucial to the establishment
of symbiotic colonies such as that seen
fluorescing red in Figure 3.
Figure 3
We have recently started a project,
in collaboration with Yorkshire Water,
to examine the use of rotting barley
straw to control cyanobacterial bloom
formation in local reservoirs.
Funding for these projects has
come from NERC, BBSRC, The
Leverhulme Trust and most recently
Yorkshire Water.
More information:
http://www.fbs.leeds.ac.uk/staff/profile.
php?staff=DGA
Representative Publications
Read, N, Connell, S & Adams, DG (2007).
Nanoscale visualization of a fibrillar array in the
cell wall of filamentous cyanobacteria and its
implications for gliding motility. J. Bacteriol.
189 (20), 7361-7366.
Duggan, PS, Gottardello, P & Adams, DG
(2007). Molecular analysis of genes in Nostoc
punctiforme involved in pilus biogenesis and
plant infection. J. Bacteriol. 189, 4547-4551.
Adams, DG, Bergman, B, Nierzwicki-Bauer, SA,
Rai, AN, Schussler, A (2006). Cyanobacterial-
Plant Symbioses, in The Prokaryotes. A
Handbook on the Biology of Bacteria, third
edition. Volume 1: Symbiotic Associations,
Biotechnology, Applied Microbiology, eds.
M. Dworkin, S. Falkow, E. Rosenberg, K.-H.
Schleifer and E. Stackebrandt. Springer, New
York, pp 331-363.
Goddard, VJ, Baker, AC, Davy, JE, Adams, DG,
De Ville, MM, Thackeray, SJ, Maberly, SC &
Wilson, WH (2005). Temporal distribution of
viruses, bacteria and phytoplankton throughout
the water column in a freshwater hypereutrophic
lake. Aquatic Microbial Ecology 39, 211-223.
Phoenix, VR, Konhauser, KO & Adams, DG,
Bottrell, SH (2001). Role of biomineralization
as an ultraviolet shield: Implications for
Archean life. Geology 29, 823-826.
Figure 1