Microcolonies within biofilms formed by a GFP-expressing
Haloferax volcanii strain bind stains targeting polysaccharide,
DNA and amyloid protein
Several H. volcanii strains were engineered to express
GFP to study ECM composition with the goal of reinforcing
and expanding staining experiments conducted by Fröls and
coworkers [38]. Confirmation of GFP expression was first
accessed within colonies formed by two GFP-expression
strains produced in this study. Colonies formed by the parental
H. volcanii H1206 strain (Figure 2A; left panel) did not
autofluoresce with blue excitation (Figure 2A, center panel),
while those formed by the H. volcanii H1206(pJAM1020)
strain based on the previously developed plasmid pJAM1020
(see Additional file 1: Table S2) [59] showed uniform and
high levels of GFP fluorescence (Figure 2A; right panel).
An additional GFP-expressing strain H. volcanii H1206
(pSC409GFP), containing the same red-shifted gfp gene
asproduced colonies with GFP signals that differed in both
intensity and spatial distribution, resulting in an assortment
of patterns of GFP signal within developed colonies
(Additional file 1: Figure S1). The H1206(pJAM1020)
strain was therefore selected for biofilm compositional
studies to ensure stable GFP expression throughout the
cellular population. in pJAM1020 but cloned into the plasmid pTA409