Article Figures & Data
Figures
- Fig. 1.
Schematic representation of the experimental design showing LFCs, CSTR, and peristaltic pumps (⊗). The silicon and chitin LFCs were run in tandem. Epi, epifluorescence.
- Fig. 2.
Histograms of RFI based on chiA gene activity in a population of cells from a GlcNAc-grown batch culture, a glutamate-grown batch culture, a 400-h starved culture, or the effluent of LFCs containing a silicon or chitin substratum at 150 h postinoculation. Cells displaying RFIs between 1 and 11 were defined as down-expressed for chiA, while cells displaying RFIs between 12 and 1,000 were defined as up-expressed for chiA. Cell counts refer to the number of cells in the population displaying a particular RFI.
- Fig. 3.
Reflected DIC (A and C) and epifluorescence (B and D) micrographs of silicon (A and B) and chitin (C and D) surfaces at 150 h postinoculation. Shown are low-magnification (B and D) and high-magnification (E and F) reflected DIC-epifluorescence image overlays showing the tight association between chiAup-expressed cells (green) and chitinase activity as reported by cleavage of the ELF-97–N-acetyl-β-d-glucosaminide enzyme substrate (red) at the single-cell level. Overlap of chiAgene activity (green) and chitinase activity (red) appears as yellow.
Tables
- Table 1.
Contribution of subpopulations to total cell population associated with chitin and silicon surfaces
Surfacea % Subpopulation (mean ± SD) chiA positive-chitinase positive chiA positive-chitinase negative chiA negative-chitinase negative chiA negative-chitinase positive Cell negative-chitinase positive Chitin 25.2 ± 7.1 31.8 ± 8.7 39.0 ± 12.4 1.33 ± 0.19 1.61 ± 0.29 Silicon 20.8 ± 4.6 44.2 ± 8.2 32.7 ± 6.1 1.25 ± 0.27 0.88 ± 0.26 ↵a A total of 1,780 and 1,149 cells were counted on the chitin and silicon surfaces, respectively.
- Table 2.
Distribution of chitinase activity among various compartments at 150 h postinoculation
Surface Rate of MUF-GlcNAc hydrolysis (μmol liter−1 h−1) (mean ± SD) Surface associated Surface associated + free enzyme + free cells Surface associated + free enzyme (<0.2-μm-pore-size filtrate) Chitin 0.47 ± 0.05 0.50 ± 0.04 0.46 ± 0.05 Silicon 0.24 ± 0.03 0.21 ± 0.02 0.22 ± 0.02
