1,6-Diphenyl-1,3,5-hexatrine as a reporter of inner spore membrane fluidity in Bacillus subtilis and Alicyclobacillus acidoterrestris.

Abstract A method to determine the inner membrane fluidity of spore populations was developed using the hydrophobic probe 1,6-diphenyl-1,3,5-hexatriene (DPH). DPH incorporated into the inner spore membrane of Bacillus subtilis ATCC 6633 and Alicyclobacillus acidoterrestris N1100, during static and dynamic fluidity experiments. The membrane fluidity of A. acidoterrestris spores stripped of the outer spore coats was the same as that of native spores. In addition, laser scanning confocal microscopy confirmed the presence of DPH in the spore membrane. This is the first report of spores containing fluid regions of their inner membranes.