Abstract
We develop an optical imaging technique for spatially and temporally tracking biofilm growth and the distribution of the main phenotypes of a Bacillus subtilis strain with a triple-fluorescent reporter for motility, matrix production, and sporulation. We develop a calibration procedure for determining the biofilm thickness from the transmission images, which is based on Beer-Lambert’s law and involves cross-sectioning of biofilms. To obtain the phenotype distribution, we assume a linear relationship between the number of cells and their fluorescence and determine the best combination of calibration coefficients that matches the total number of cells for all three phenotypes and with the total number of cells from the transmission images. Based on this analysis, we resolve the composition of the biofilm in terms of motile, matrix-producing, sporulating cells and low-fluorescent materials which includes matrix and cells that are dead or have low fluorescent gene expression. We take advantage of the circular growth to make kymograph plots of all three phenotypes and the dominant phenotype in terms of radial distance and time. To visualize the nonlocal character of biofilm growth, we also make kymographs using the local colonization time. Our technique is suitable for real-time, noninvasive, quantitative studies of the growth and phenotype distribution of biofilms which are either exposed to different conditions such as biocides, nutrient depletion, dehydration, or waste accumulation.
Similar content being viewed by others
References
Barnett TA, Valenzuela D, Riner S, Hageman JH (1983) Production by Bacillis subtilis of brown sporulation-association pigments. Can J Microbiol 29(1):96–101
Branda SS, González-Pastor JE, Ben-Yehuda S, Losick R, Kolter R (2001) Fruiting body formation by Bacillus subtilis. Proc Natl Acad Sci U S A 98:11621–11626
Branda SS, González-Pastor JE, Dervyn E, Ehrlich SD, Losick R, Kolter R (2004) Genes involved in formation of structured multicellular communities by Bacillus subtilis. J Bacteriol 186(12):3970–3979
Chang S, Cohen SN (1979) High frequency transformation of Bacillus subtilis protoplasts by plasmid DNA. Mol Gen Genet MGG 168(1):111–115
Chen Y, Yan F, Chai Y, Liu H, Kolter R, Losick R, Guo JH (2013) Biocontrol of tomato wilt disease by Bacillus subtilis isolates from natural environments depends on conserved genes mediating biofilm formation. Environ Microbiol 15(3):848–864
Chudakov DM, Matz MV, Lukyanov S, Lukyanov KA (2010) Fluorescent Proteins and Their Applications in Imaging Living Cells and Tissues. Physical Rev 90:1103–1163. doi:10.1152/physrev.00038.2009
Costerton J, Stewart PS, Greenberg E (1999) Bacterial biofilms: a common cause of persistent infections. Science 284(5418):1318–1322
Curtis PD, Taylor RG, Welch RD, Shimkets LJ (2007) Spatial organization of Myxococcus xanthus during fruiting body formation. J Bacteriol 189(24):9126–9130
Dervaux J, Magniez JC, Libchaber A (2013) On growth and form of Bacillus subtilis biofilms. Interface Focus 4(6):20130051
Doherty GP, Bailey K, Lewis PJ (2010) Stage-specific fluorescence intensity of GFP and mCherry during sporulation In Bacillus subtilis. BMC Res Notes 3:303
Dubnau D (1991) Genetic competence in Bacillus subtilis. Microbiol Rev 55:395–424
Dubnau D, Provvedi R (2000) Internalizing DNA Res Microbiol 151:475–480
Eisele TC, Gabby KL (2014) Review of Reductive Leaching of Iron by Anaerobic Bacteria. Miner Process Extr Metall Rev 35(2):75–105
Evdokimov AG, Pokross ME, Egorov NS, Zaraisky AG, Yampolsky IV, Merzlyak EM, Shkoporov AN, Sander I, Lukyanov KA, Chudakov DM (2006) Structural basis for the fast maturation of Arthropoda green fluorescent protein. EMBO Rep 7:1006–1012
Falk MM, Baker SM, Gumpert AM, Segretain D, Buckheit RW (2009) Gap junction turnover is achieved by the internalization of small endocytic double-membrane vesicles. Mol Biol Cell 20:3342–3352
Gardel EJ, Nielsen ME, Grisdela PT, Girguis PR (2012) Duty cycling influences current generation in multi-anode environmental microbial fuel cells. Environ Sci Technol 46(9):5222–5229
Golden JW, Yoon HS (2003) Heterocyst development in Anabaena. Curr Opin Microbiol 6(6):557–563
Gonzalez-Pastor JE, Hobbs EC, Losick R (2003) Cannibalism by sporulating bacteria. Science 301:510–513
Hall-Stoodley L, Stoodley P (2009) Evolving concepts in biofilm infections. Cell Microbiol 11(7):1034–1043
Hottes AK, Shapiro L, McAdams HH (2005) DnaA coordinates replication initiation and cell cycle transcription in Caulobacter crescentus. Mol Microbiol 58(5):1340–1353
Kearns DB, Losick R (2005) Cell population heterogeneity during growth of Bacillus subtilis. Genes Dev 19:3083–3094
Kearns DB, Chu F, Branda SS, Kolter R, Losick R (2005) A master regulator for biofilm formation by Bacillus subtilis. Mol Microbiol 55(3):739–749
Logan BE (2008) Microbial fuel cells. John Wiley & Sons
Mazza F (1994) The use of Bacillus subtilis as an antidiarrhoeal microorganism. Boll Chim Farm 133(1):3–18
O’Toole G, Kaplan HB, Kolter R (2000) Biofilm formation as microbial development. Annu Rev Microbiol 54(1):49–79
Piggot PJ, Hilbert DW (2004) Sporulation of Bacillus subtilis. Curr Opin Microbiol 7:579–586
Rudner DZ, Losick R (2001) Morphological coupling in development: lessons from prokaryotes. Dev Cell 1:733–742
Seminara A, Angelini TE, Wilking JN, Vlamakis H, Ebrahim S, Kolter R, Weitz DA, Brenner MP (2012) Osmotic spreading of Bacillus subtilis biofilms driven by an extracellular matrix. Proc Natl Acad Sci U S A 109(4):1116–1121
Shemesh M, Chai Y (2013) A combination of glycerol and manganese promotes biofilm formation in Bacillus subtilis via the histidine kinase KinD signaling. J Bacteriol 195:2747–2754
Singh R, Paul D, Jain RK (2006) Biofilms: implications in bioremediation. Trends Microbiol 14(9):389–397
Swain MR, Ray RC (2009) Biocontrol and other beneficial activities of Bacillus subtilis isolated from cowdung microflora. Microbiol Res 164(2):121–130
Verplaetse E, Slamti L, Gohar M, Lereclus D (2015) Cell Differentiation in a Bacillus thuringiensis population during planktonic growth, biofilm formation, and host infection. Mbio 6(3):00138–00115
Vila J, Tauler M, Grifoll M (2015) Bacterial PAH degradation in marine and terrestrial habitats. Curr Opin Biotechnol 33:95–102
Vlamakis H, Aguilar C, Losick R, Kolter R (2008) Control of cell fate by the formation of an architecturally complex bacterial community. Genes Dev 22:945–953
Vlamakis H, Chai YR, Beauregard P, Losick R, Kolter R (2013) Sticking together: building a biofilm the Bacillus subtilis way. Nat Rev Microbiol 11(3):157–168
Wiedenmann J, Oswald F, Nienhaus GU (2009) Fluorescent proteins for live cell imaging: opportunities, limitations and challenges. IUBMB Life 61(11):1029–1042
Acknowledgments
We thank Richard Losick’s group and Roberto Kolter’s group for providing triple-fluorescent-labeled Bacillus subtilis strains. This work was supported by the National Science Foundation (DMR-1310266, DMS-1411694), the Harvard Materials Research Science and Engineering Center (DMR-1420570), the National Natural Science Foundation of China (11272002), and the Beijing Higher Education Young Elite Teacher Project (YETP0363).
Author information
Authors and Affiliations
Corresponding authors
Ethics declarations
Funding
The National Science Foundation (DMR-1310266, DMS-1411694), the Harvard Materials Research Science and Engineering Center (DMR-1420570), the National Natural Science Foundation of China (11272002), and the Beijing Higher Education Young Elite Teacher Project (YETP0363).
Conflict of interest
The authors declare that they have no conflict of interest.
Ethical approval
This article does not contain any studies with human participants or animals performed by any of the authors.
Rights and permissions
About this article
Cite this article
Wang, X., Koehler, S.A., Wilking, J.N. et al. Probing phenotypic growth in expanding Bacillus subtilis biofilms. Appl Microbiol Biotechnol 100, 4607–4615 (2016). https://doi.org/10.1007/s00253-016-7461-4
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00253-016-7461-4