Sodium Dodecyl Sulfate-Polyacrylamide Gel Protein Electrophoresis of Freshwater Photosynthetic Sulfur Bacteria
- 160 Downloads
Sodium dodecyl sulfate-polyacrylamide gel protein electrophoresis (SDS-PAGE) was carried out using different bacterial strains of the photosynthetic sulfur bacteria Chlorobium, Thiocapsa, Thiocystis, and Chromatium cultured in the laboratory, and the natural blooms in two karstic lakes (Lake Cisó and Lake Vilar, NE Spain) where planktonic photosynthetic bacteria (purple and green sulfur bacteria) massively developed accounting for most of the microbial biomass. Several extraction, solubilization, and electrophoresis methods were tested to develop an optimal protocol for the best resolution of the SDS-PAGE. Protein composition from different water depths and at different times of the year was visualized within a molecular mass range between 100 and 15 kDa yielding up to 20 different protein bands. Protein banding patterns were reproducible and changed in time and with depth in agreement with changes in photosynthetic bacteria composition. When a taxonomically stable community was followed in time, differences were observed in the intensity but not in the composition of the SDS-PAGE banding pattern. Three environmental variables directly related to the activity of sulfur bacteria (light, oxygen, and sulfide concentrations) had a significant effect on protein banding patterns and explained 33% of the variance. Changes in natural protein profiles of the bacterial blooms agreed with changes in species composition and in the in situ metabolic state of the populations.
KeywordsPhotosynthetic Bacterium Green Sulfur Bacterium Bacterial Assemblage Natural Population Analysis Purple Sulfur Bacterium
We thank Montse Carrascal and Joaquín Abián from the Laboratory of Proteomics CSIC-UAB for advice in samples processing, and Albert Barberan for statistics. Work supported by grants VIARC REN2003-08333 and CRENYC CGL2006-12058 from the Spanish Ministerio de Educación y Ciencia (MEC) to EOC. MBO received a I3P postdoctoral fellow from the Spanish Council for Research (CSIC).
- 3.Casamayor EO (2010) Vertical distribution of planktonic autotrophic thiobacilli and dark CO2 fixation rates in lakes with oxygen–sulfide interfaces. Aquat Microb Ecol 59(3). doi: 10.3354/ame01399
- 4.Casamayor EO, Schafer H, Pedrós-Alió C, Muyzer G (2000) Identification of and spatio-temporal differences between microbial assemblages from two neighboring sulfurous lakes: comparison by microscopy and denaturing gradient gel electrophoresis. Appl Environ Microbiol 66:499–508CrossRefPubMedGoogle Scholar
- 21.Oksanen J, Kindt R, Legendre P, O’hara B, Simpson GL, Stevens MHH (2008) Vegan: Community Ecology Package. Version 1.11-4. http://vegan.r-forge.r-project.org
- 22.Pedrós-Alió C, Guerrero R (1993) Microbial ecology in Lake Cisó. Adv Microb Ecol 13:155–209Google Scholar
- 23.Pfennig N, Trüper HG (1989) Anoxygenic phototrophic bacteria. In: Murray RGE, Brenner DJ, Bryant MP, Holt JG, Krieg NR, Moulder JW, Pfennig N, Sneath PHA, Staley JT, Williams ST (eds) Bergey’s manual of systematic bacteriology, vol 3, sect 18. Williams and Wilkins, Baltimore, pp 1635–1653Google Scholar
- 26.Shannon CE, Weaver W (1949) The mathematical theory of communication. University of Illinois Press, Urbana, ILGoogle Scholar
- 29.van Gemerden H, Mas J (1995) Ecology of phototrophic sulfur bacteria. In: Blankenship RE, Madigan MT, Bauer CE (eds) Anoxygenic photosynthetic bacteria. Kluwer Academic Publishers, Dordretch, The Netherlands, pp 49–85Google Scholar