Differences in the surface membranes and water content between the vegetative cells and spores of Bacillus subtilis

Bacillus subtilis forms both vegetative cells and spores, The fluidity of t he membranes in these forms was measured by using fluorescent anisotropy of 1,6-diphenyl-1,3,5-hexatriene (DPH). The spores were more rigid than the v egetative cells, suggesting that the structure of the spores and vegetative cells was different. This difference was thought to be due to the structur e of the cell membranes. The anisotrophy of DPH in the cell membranes of sp ores gave higher values at all temperatures. The anisotrophy of DPH in the cell membranes of vegetative cells was lower than that of the spores and th e value depended upon the temperature, Time Domain Reflectometry (TDR) was used to measure the quantities of bound and free water in the vegetative ce lls and spores. The spores were dehydrated, and the amount of bound and fre e water in the spores was about two-thirds of the levels in the vegetative cells. The spores have fewer sugars molecules on their cell surface membran es, but contained as much sugars within the cell. Almost 100 per cent of th e vegetative cells wee absorbed toward chitin, but the spores were not abso rbed toward it at all. It was felt that the surface membrane of the vegetat ive cell had a high mobility because it was sugar-rich, while the surface m embrane of the spore showed a lower mobility because there an fewer sugars on the outer membrane. The spores survive in high temperatures because the surface membrane of the spore is tight and has relatively few sugars. Dehyd ration causes the rigidity of the spores. On the other hand. the vegetative cells are sugar- and water-rich. which makes them more fluid. The differen ce between the vegetative cells and spores is the glycosylation of their su rface membranes. Copyright (C) 1999 John Wiley & Sons, Ltd.