X-ray diffraction studies of the sulfur globules accumulated by Chromatium species

Isolated wet and dried sulfur globules, obtained by osmotic lysis of lysozyme-ethylenediaminetetraacetic acid prepared spheroplasts of Chromatium okenii, C. weissei, and C. warmingii, were studied by polarizing microscopy and X-ray diffraction. When viewed through crossed Nicol prisms, the sulfur globules, whether in the cell or isolated in a pure, wet state, had a characteristic maltese cross appearance. The observation that rotation of the mount did not change the orientation of the arms suggested a symmetrical radial arrangement of the birefringent units. X-ray diffraction patterns of freshly isolated, wet sulfur globules gave two broad and diffuse diffraction rings with maxima at 0.36 and 0.52 nm. This pattern closely resembled the diffraction pattern of liquid sulfur. When allowed to stand in the wet state, the sulfur globules eventually converted into crystalline orthorhombic sulfur after passing through an unstable crystalline phase not previously described by X-ray diffraction. Vacuum drying of the sulfur globules accelerated the change into crystalline orthorhombic sulfur.