William R. Mayberry

A sulfonolipid and novel glucosamidyl glycolipids from the extreme thermoacidophile Bacillus acidocaldarius

The total lipid content of the extreme thermoacidophile Bacillus acidocaldarius comprises about 8.1% of the cell dry weight. Total lipid had a distribution of 15.7% neutral linique component initially characterized as an N-acylglucosamine beta-linked to the primary hydroxyl of an unusual fully saturated pentacyclic triterpene derived tetrol(C35H62O4, Mr 546), which appears to be a derivative of the pentacylcic triterpene hopane substituted at C-29 with a 1,2,3,4-tetrahydroxy pentane. Other major glycolipids present were partially characterized as O-beta-D-glucopyranosyl-(1 leads to 4)-O-2-acylamido-2-deoxy-beta D-glucopyranosyldiacylglycerol and O-beta-D-glucopyranosyl-(1 leads to 4)-O-2-acylamido-2-deoxy-beta-D-glucopyranosylmonoacylglycerol. Minor components of the glycolipid fraction included O-beta-D-glucopyranosyl-(1 leads to 4)-O-2-acylamido-2-deoxy-beta-D-glucopyranosylglycerol, O-2-amino-2-deoxy-beta-D-glucopyranosyl pentacyclic tetrol and free pentacyclic tetrol. The distributions of esterified and amide-linked fatty acids were similar, being comprised primarily of branched heptadecanoic, 11-cyclohexyundecanoic and 13-cyclohexyltridecanoic acids. The acid lipids were composed of a sulfonoglycosyldiacylglycerol (43.2%), diphosphatidylglycerol (32.3%), lysodiphosphatidylglycerol (5.3%), phosphatidic acid (5.8%) and phosphatidylglycerol (13.4%).

A new class of lipopolysaccharide from Thermoplasma acidophilum

Abstract A hot aqueous phenol extraction of lipid extracted whole cells of Thermoplasma acidophilum yielded a polymer that comprises 97% of the aqueous phase. The polymer is composed of 80% carbohydrate and 20% glycerol diether. Analysis of this polymer showed a ratio of 25:1:2 of carbohydrate: glycerol: alkane. The carbohydrate was composed of mannose and glucose in a ratio of 24:1. The alkyl glycerol terminus is a 1,2-glycerol diether composed of forty carbon isopranol side chains. The molecular weight of the polymer is greater than 1200 000. The polymer can be dissociated with 0.5% sodium dodecylsulfate to yield a molecular weight of 67 000. A monomer appears to be approx. 5300. The molecular weight of the alkanes in the polymer is 560. Most, if not all of the mannosidic linkages are alpha (α) since α-mannosidase releases 95% of the mannose. The tentative structure of the lipopolysaccharide is (mannose) 24 -glucose-glycerol diether.

LIPIDS OF MYCOPLASMAS

Knowledge of the structure and metabolism of mycoplasmal lipids can serve to explain many important aspects of this group of microorganisms, e.g. membrane structure, transport phenomena, survival, taxonomic relationships, evolutionary origin, and possibly even pathogenesis. This presentation will deal exclusively with the structure of mycoplasmal lipids in relation to speciation and to analogous lipids in bacteria. The phospholipids of the vast majority of mycoplasmas examined are composed of the acidic glycerophosphate type (TABLE 1) . These include the whole range from phosphatidic acid through the fully acylated glycerophosphoryl glycerophosphoryl glycerol. With the exception of two organisms the phospholipids cannot be considered distinctive. The one T-strain studied contains phosphatidyl ethanolamine and a diamino compound possessing 0-acyl and N-acyl group^.^ Acholeplasma axanthum contains ceramide phosphoryl glycerols similar to Bacteroides.B The amino group of the long-chained base in this lipid is attached to a hydroxy acid in an N-acyl linkage. These lipids, as a class, contain a series of fully saturated long-chained bases of varying chain lengths. The hydroxy group of the hydroxy fatty acid is in the P position but in the unnatural L configuration. On the basis of phospholipid structures, the T-strain and A . axanthum are distinct from Mycoplasma and other Acholeplasma species. A similar picture is seen with the neutral lipids. Although fatty acids and longchained bases are polar lipids, they are included with neutral lipids as a matter of convenience. All Mycoplasma species and the T-strain contain sterol incorporated from an exogenous source (TABLE 2) . Two Acholeplasma species contain carotenoids. A axanthum possesses a mixture of long-chained bases and free fatty acids.s If these charged lipids are so situated in the membrane as to neutralize one another, their fit and function would be analogous to sterols and carotenoids. The large amounts of free fatty acids in the T-strain may reflect a response to their natural alkaline environment. Thermoplasma acidophilum has among its neutral lipids a series of hydrocarbons varying in chain length from CI4 to C32. Glycerides are distributed in small quantities among all of the mesophilic mycoplasmas. On the other hand, Th. acidophilum contains glycerol monoand diethers, undoubtedly reflecting its acidophilic nature. The existence of the naphthoquinone, vitamin K2-7, in this organism suggests an oxidative respiratory pathway. The nature of the neutral and phospholipids: (1) permits the separation of Mycoplasma from Acholeplasma and other genera; (2) suggests an unrelatedness of A. axanthum with other acholepiasmas; (3) isolates T-strains from Mycoplasma and Acholeplasma; and (4) defines a uniqueness for Thermoplasma Glycolipid structures are even more revealing. Glycolipids can be viewed as the counterparts in mycoplasmas and grampositive bacteria of the lipopolysaccharides found in the surface structures of the

Structure of the mannoheptose-containing pentaglycosyldiacylglycerol from Acholeplasma modicum

Abstract The pentaglycosyldiacylglycerol from Achqleplasma modicum strain Squire (PG 49) has the structure: D-galactopyranosyl-(1 2-D-galactopyranosyl-(1 3)- d -glycero- d -mannoheptopyranosyl-(1 3)- d -glucopyranosyl-(1 2)- d -glucopyranosyl-(1 1)-diacylglycerol.