The fatty acid composition of two thermophilic anaerobes was determined, and the results were compared with those from a mesophilic and a psychrophilic anaerobe. Notable differences were that the thermophiles contained a higher content of saturated straight- and branched-chain fatty acids, and, of the latter, iso C 15 was the predominant type. The mesophile and psychrophile were characterized by having a higher percentage of unsaturated fatty acids. An unidentified fatty acid, present in all of the organisms, was purified from the psychrophile. By physical and chemical analysis the structure of the unknown acid was resolved and found to be the unsaturated cyclopropane fatty acid, 12,13-methylene-9-tetradecenoic acid.

The bisulfite reductase (P582) from Desulfotomaculum nigrificans was purified to homogeneity as judged by polyacrylamide gel electrophoresis. By colorimetric methods of analysis, the products of bisulfite reduction by this enzyme were determined to be trithionate, thiosulfate, and sulfide. Of these, trithionate was consistently found to be the major product, whereas the latter two were formed in lesser quantities. When [35S]bisulfite was incorporated as substrate, no labeled sulfide was detected. Furthermore, when trithionate and thiosulfate were isolated from reaction mixtures and chemically degraded, 35S was found in all three sulfur atoms of trithionate; however, only the inner sulfur atom of thiosulfate was radioactive. From these data we conclude that the bisulfite reductase of D. nigrificans reduces bisulfite to trithionate and that thiosulfate and sulfide are endogenous side products of the reaction.

Spin-labeling studies were conducted to elucidate the rigidity and viscosity of the membrane of a facultative thermophilic bacillus. By employing nitroxide stearate probes, it was observed that this fatty acid was incorporated into the membrane fraction. Electron spin resonance spectroscopy indicated that cells grown at 55 C contained a membrane which was more rigid and viscous than the membrane from cells grown at 37 C. 322 on July 31, 2020 by guest

The morphology and cell wall composition of Bacillus coagulans , a facultative thermophile, were examined as a function of growth temperature. The morphology of the organism varied when it was grown at different temperatures; at 37 C the organism grew as individual cells which increased in length with increasing growth temperature. At 55 C it grew in long chains of cells. Cell wall prepared from cells grown at 37 C contained 44% teichoic acid by weight, whereas cells grown at 55 C contained 29% teichoic acid. Teichoic acid from these cells was a polymer of glycerol phosphate containing galactose and ester alanine. The ratio of ester alanine to phosphate was significantly higher in cell walls and teichoic acid from 37 C-grown cells compared with those from 55 C-grown cells. Other differences observed were that cells grown at 55 C contained a lower level of autolytic ability, produced cell walls which bound more Mg 2+ , and contained less peptide cross-bridging in its peptidoglycan layer than cells grown at 37 C.

The lipopolysaccharide previously isolated from the rickettsial agent of Q fever, Coxiella burneti, phase I, has been further characterized. The sugar residues ribose, mannose, glucose, D-glycero-D-mannoheptose, and L-glycero-Dmannoheptose are present. Two sugars remain unidentified, one of which is a minor and the other a major constituent. Isomyristic, palmitic, and /3-hydroxymyristic acids are the major fatty acid residues of the 15 identified. The nature and content of other lipopolysaccharide constituents are presented.Toxins have been identified in several rickettsial species, but until recently no endotoxin had been described for Coxiella burneti, the rickettsial agent of Q fever. Baca and Paretsky prepared a lipopolysaccharide (LPS) from C. burneti, phase I, which has many pharmacological properties characteristic of the endotoxins of gram-negative bacteria (3). We now describe a more extensive chemical characterization of the LPS of C. burneti.MATERIALS AND METHODS C. burneti, Nine Mile strain, phase I, was cultivated in embryonated eggs and subsequently purified from infected yolk sacs (33). The LPS was prepared by a modified hot phenol-water method (4, 36). Purified rickettsiae (2 to 4 g, wet weight) were suspended in 20 ml of 0.02 M phosphate buffer-0.15 M KCl, pH 7.4 (PK), and 20 ml of 90% redistilled phenol (wt/wt), 68 C, was immediately added. The suspension was vigorously shaken for 20 min in a water bath at 68 C. The emulsion was centrifuged at 3,000 x g for 15 min, and the aqueous phase was collected. The residual interphase and phenolic phase were extracted twice more with an equal volume of PK, and the aqueous phases were collected, pooled, and dialyzed against running tap water for 3 days. The residual opalescent solution was centrifuged at 10,000 x g for 20 min at 4 C. To the supernatant were added enough 0.5 M tris(hydroxymethyl)aminomethane buffer and 0.5 M MgCl2 to give a final concentration of 0.025 M tris(hydroxymethyl)aminomethane, pH 7.5, and 0.01 M MgCl2, together with 100 gg of ribonuclease (Sigma type