Physical and chemical studies of Thiobacillus ferroxidans lipopolysaccharides

Abstract

The lipopolysaccharides (LPS) of the obligate acidophile Thiobacillus ferrooxidans grown on iron, sulfur, and glucose as energy sources were examined for various physical and chemical properties. Both qualitative and quantitative variations were found among the three preparations. The LPS extracted from iron-grown cells (Fe-LPS) contained less than 3% protein compared to 18 to 25%c in LPS extracted from either sulfur-grown cells (S-LPS) or glucose-grown cells (G-LPS). S-LPS showed two distinct sedimentable species. 61S and 9.3S, which could be fractionated on a column of Sepharose 4B. The relative densities of' both S-LPS and G-LPS were found to be significantly greater than that of Fe-LPS. Spectral differences were noted when each LPS was reacted with a carbocyanine dye. Fe-LPS showed a single absorbance maximum at 472 nm, S-LPS displayed its maximum at 650 nm, and G-LPS showed two maxima, the first at 468 nm and the other at 655 nm. Analysis of the methyl ester derivatives of the LPS t'atty acids using gas chromatography-mass spectrometry revealed the presence of' a very stable species, tentatively identified as a methoxy methyl ester with a formula of CH3-O-C10H10-COOCH3, as the major component from each LPS. 3-Hydroxymyristic acid was found only in Fe-LPS.

Solubilization of Minerals by Bacteria: Electrophoretic Mobility of Thiobacillus ferrooxidans in the Presence of Iron, Pyrite, and Sulfur

“…Bands that stained yellow contained carbohydrate, while bands that stained blue were predominantly proteinaceous. Other laboratories have reported that the lipopolysaccharides of T. ferrooxidans grown on soluble ferrous ions or sulfur are chemically different (13,31) or identical (34) for different strains. The difference in banding patterns in Fig.…”

Inhibitory action of a non-metabolizable fatty acid on the growth of Escherichia coli: role of metabolism and outer membrane integrity

“…In turn, the proteins of the outer membrane are strongly influenced by the conditions of growth (1, 3, 18); e.g., growth phase, carbon source, and catabolite repression change the composition of the major protein group in the E. coli outer membrane (18). Also, the LPS composition changes in different culture media (11,17). In the relationship presented in Fig.…”

Signature fatty acids in the polar lipids of acid-producingThiobacillusspp.: Methoxy, cyclopropyl, alpha-hydroxy-cyclopropyl and branched and normal monoenoic fatty acids

“…The decreased yield of cyclopropane fatty acids in bacterial lipid preparations formed with acid hydrolysis has been known for a long time [30]. A methoxy fatty acid has been defined by GC/MS in the lipopolysaccharide-lipid A of Thiobacillusferrooxidans [31]. It was this paper that encouraged us to examine the lipids of other Thiobacillus spp., using the mild alkaline methanolysis procedure, for signature PLFA that could be utilized in environmental studies.…”