PHASE PARTITIONING OF CELLS
For assessing hydrophobicity
of the cell surface
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Grow cells to midlog phase, centrifuge and concentrate 10
fold.
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Prepare phases by adding volumes of 20% (w/w) polyethylene
glycol 6000 Sigma) and 20% (w/w) Dextran T500 (Pharmacia) to give final
concentrations of 4.4% and 6.2%, respectively, in 30mM Tris-HCl buffer,
pH 7.0. Equilibriate at 4C. for several hours to allow separation into
the 2 phases.
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Add 1 ml of each of the top and bottom phases. Add 0.1 ml
of Triton X-100 and 0.1 ml of the concentrated cells.
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Invert tubes 20x and leave to equilibrate for 45 min. at
room temperature.
Take a sample from both the top and the bottom phases. The
OD of each of these samples is measured in a spectrophotometer at 600 nm.
Results may be expressed as the ratio of the top/bottom phases.
Updated 01 December 2000.