Abh: A novel activator of Bacillus subtilis biofilm formation

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Abh A novel activator of Bacillus subtilis
biofilm formation

• Ewan Murray
• University of Dundee, UK

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Unicellular organisms
Bacillus subtilis
Enterococcus faecalis
Escherichia coli
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Multicellular behaviour processes
Biofilm Formation
Quorum Sensing
Sporulation
Genetic Competence
Swarming
Cannibalism
Richard Losick et al.
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Microbial biofilms

• Proposed major bacterial life-style in nature
• Community of cells often of different species
• Adherent to a solid surface or interface
• Coated in a complex polymeric matrix

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Why are biofilms important ?
GOOD
BAD
Pipe corrosion
Energy production
Sewage treatment
Animal/plant disease
Bio-control
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Bacillus subtilis and biofilm formation
Complex colony architecture
Planktonic Bacillus subtilis
Plant root adhered biofilm
Pellicle
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Spatial and temporal coordination
Schematic representation of complex colony
development based on the results of Vlamakis et
al., 2008
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Simplified regulation of matrix production by
Spo0AP
Work from the labs of Kolter, Losick and Lazazzera
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Abh a B.subtilis AbrB homologue
(structures Bobay et al., 2006)

• Share overlapping antimicrobial regulon
  (Strauch et al., 2007)

Q Does Abh regulate biofilm formation?
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How does Abh activate biofilm formation ?
Microarray analysis was used to determine
potential Abh regulated genes
wt/Dabh expression
Total number of differentially expressed genes
Biofilm associated genes
65 genes Identified 62 activated by Abh 3
repressed by Abh
expression down regulated in an abh mutant
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Regulation of matrix production by SlrR
AbrB
SinR
SlrR
yqxM-sipW-tasA
epsA-O
Kobayashi, 2008 and Chu et al., 2008
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Matrix production is bi-stable
Schematic representation of complex colony
development based on the results of Vlamakis et
al., 2008
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Transcription from the eps and yqxM promoters is
bi-stable
gfp
promoter element of matrix encoding operon
driving GFP expression
Laser detects fluorescent signal from each
individual cell
Cells within a complex colony are released by
gentle sonication
Protocol taken from Vlamakis et al., 2008
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Bi-stable expression
OFF
ON
Cell number
Fluorescence (AU)
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slrR induction, potential results
expression is increased in all cells
expression level is maintained but all cells
switch on expression
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Taryn
Adam
Nicola
Chung-Seon
Thanks to
The Division of Molecular Microbiology. Media
Kitchen Sequencing Service Wash-up Stores
Lab manager
Jackie
Dyce