1

Swimming Motility Reduces Azotobacter vinelandii 1

Deposition to Silica Surfaces 2

Nanxi Lu1, Arash Massoudieh2, Xiaomeng Liang2, Dehong Hu3, Tamir Kamai4, Timothy 3

R. Ginn5, Julie L. Zilles1, Thanh H. Nguyen1 4

Supplementary information: containing 3 pages and 3 figures 5

Submitted to 6

Special Issue of Journal of Environmental Quality on Microbial Transport and Fate in 7

the Subsurface 8

1. Department of Civil and Environmental Engineering, University of Illinois at 9

Urbana-Champaign, Urbana Illinois 61801, United States 10

2. Civil Engineering Department, The Catholic University of America, 620 11

Michigan Ave. NE, Washington, DC 20064, United States 12

3. Environmental Molecular Sciences Laboratory, Pacific Northwest National 13

Laboratory, 902 Battelle Blvd., Richland, Washington 99352, United States 14

4. Institute of Soil, Water and Environmental Sciences, Agricultural Research 15

Organization, Bet Dagan, Israel 16

5. Department of Civil and Environmental Engineering, University of California, 17

Davis, United States 18

Keywords: swimming motility, porous media, trajectory analysis, bacterial transport 19

Corresponding author: nanxi.lu@northwestern.edu 20

2

21

Figure S1 Motility of A. vinelandii strains. Mean square displacement versus time for 22 each strain/condition. DJ is a wild type strain, while DJ77 has restricted motility. JZ52 23 lacks motility and flagella and FCCP treatment de-energizes DJ cells, rendering them 24 non-motile. The motility tests were done in MOPS buffer with 100 mM KCl, pH 7.2. 25 Videos were taken at a frequency of 31 Hz. 26

27

28

3

29

Figure S2 Representative cell trajectories from A) motile strain DJ and B) non-motile 30 FCCP-treated DJ in RSPF experiments, depicting the cells 20 µm above the RSPF quartz 31 surface moving along with the flow stream. The white arrows indicate the flow direction 32 within RSPF chambers. 33

4

34

Figure S3 Surface characterization of all bacterial strains and surfaces. The 35 electrophoretic mobility of strain DJ was measured using a Zetasizer Nano ZS90 36 (Malvern Instruments, Southborough, MA) in MOPS buffer solutions with 1-100 mM 37 KCl at pH 7.2. The cell concentration was diluted to 3.0×106 cells/mL. Electrophoretic 38 mobility for strains DJ77 and JZ52 and materials used in this work were reported 39 previously and are included here for comparison (Lu, et al., 2013). 40

41

Reference: 42

Lu, N., T. Bevard, A. Massoudieh, C. Zhang, A.C. Dohnalkova, J.L. Zilles, et al. 2013. 43 Flagella-mediated differences in deposition dynamics for Azotobacter vinelandii in 44 porous media. Environmental Science & Technology 47: 5162-5170. 45

46

47