Degradative Effect of Phenol on Endotoxin and Lipopolysaccharide Preparations from Serratia marcescens

Abstract

It has been established that the well-known deproteinizing action of hot 45% aqueous phenol on whole cells or isolated and purified endotoxin of Serratia marcescens 08 is caused by the cleavage of a phenol-sensitive linkage within the lipid moiety. As a result of this degradation, both the lipopolysaccharide and simple protein fragments retained a part of the lipid moiety. Although not proceeding at the same fast rate as the cleavage of the lipid moiety, such phenol treatment also caused a partial hydrolysis of the O-specific side chain and ester-bound fatty acids. Hydrolysis of the O-specific side chain accounted for 5% of the lipopolysaccharide and that of ester-bound fatty acids accounted for 11% of the total fatty acid content after 60 min of treatment. It is suggested that the presence of these degradation products is one of the main causes of the heterogeneity of endotoxin and lipopolysaccharide preparations.

Characteristics of lipid A-protein complex from endotoxin of Shigella dysenteriae type 1 (S and R strains)

“…Thus, taken together, the results obtained indicate that the protein present in LPSP and, in particular, associated with the lipid A-protein complex is a constituent part thereof. This is fully confirmed by some earlier studies (16,26,29,36) concerned with the significance of protein in preparations of endotoxin, LPSP, or lipid A of some other bacteria (34,35). This protein moiety, which seems to be covalently bound to lipid A (26), may be released from the complex in a number of ways.…”

“…The principal portion of lipid A, 70 to 80%, is fatty acids, and the remainder is the sugar moiety (amino sugar) and phosphorus. However, a different situation arises if, instead of LPS, the starting material has been LPSP complex (which is the case herein with S. dysenteriae type 1 since phenol-water extraction was not used in order to avoid possible degradation of some endotoxin component [29,35]). It is then not surprising that treatment with a weak acid yields a lipid A-protein complex with a relatively high proportion of protein (31).…”

Bacterial lipopolysaccharides as inducers of disease resistance in tobacco

“…As pointed out by Nowotny (27), chemical modifications provide useful, but inconclusive, information regarding the active LPS components. This problem is compounded by the current lack of understanding of the minor linkages of the LPS, especially those involving amino acid residues in the lipid A section (25,27,39). The use of a series of rough mutants, especially Re mutants, which contain only lipid A and KDO (20), may be useful in complementing the results reported here from chemical studies.…”

Stimulation of human monocytes by endotoxin-associated protein: inhibition of programmed cell death (apoptosis) and potential significance in adjuvanticity

“…Endotoxin-associated protein (EP) consists of a complex of four or five major proteins that range in size from 10 to 35 kDa and that are intimately associated with the lipopolysaccharide (LPS) of gram-negative bacteria (3,10). EP can be purified from LPS by hot phenol extraction (18,21) and contains 85% protein, 2.2% glucosamine, and -10% certain fatty acids characteristic of lipid A (3). However, there is no evidence of 2-keto-3-deoxyoctonate and thus no LPS core in EP.…”