Lipid and lipopolysaccharide composition of Acholeplasma oculi

Abstract

The total lipid content of Acholeplasma oculi comprises 13.3% of the dry weight of the organism and is about equally distributed between the neutral lipids plus glycolipids and the phospholipids. The phospholipids were identified as phosphatidyl glycerol and diphosphatidyl glycerol. The glycolipid fraction contained O-a-D-glucopyranosyl-(l --1)-2,3-diacyl glycerol and 0-a-D-glucopyranosyl-(1 -* 2)-O-a-D-glucopyranosyl-(1 -. 1)-2,3-diacyl glycerol. The neutral lipid contained pigmented carotenoids. Hot aqueous phenol extraction of lipid-extracted whole cells yielded a polymeric carbohydrate comprising 2.3% of the dry weight of the organism. The A. oculi lipopolysaccharide was found to contain only neutral sugars and no amino sugar, in contrast to other acholeplasmas. The neutral sugars consisted of fucose, galactose, and glucose in a ratio of 2:19:3.The occurrence of Acholeplasma oculi as a potential pathogen in goats was reported by Al-Aubaidi et al. (1). Isolation of this organism from horses (2) and camels (3) has been reported recently. Mycoplasmal components, such as glycolipids, phosphoglycolipids, and lipopolysaccharides, have been found (15) to be of significance not only because of their role in structure and function of membranes, but also because of their antigenic reactivity. This suggested their potential importance as specific antigenic determinants which could aid in the taxonomic classification of mycoplasmas. A. oculi was selected for study because this species is representative of a type not yet examined. The results show that the lipopolysaccharides of this organism are distinct from other acholeplasmas examined thus far.MATERIALS AND METHODS Growth of cells. A. oculi 19L was grown in tryptose broth containing 1% yeast extract, 1% glucose, and 1% (vol/vol) PPLO serum fraction (Difco Laboratories, Detroit, Mich.). The usual batch of organisms consisted of 90 liters of an 18-h-old culture stpted from 10% inoculum grown in the same liquid medium for multiple transfers. Incubation was carried out statically at 370C in 2-liter volumes contained in 3-liter flasks. Growth was followed by visual examination for turbidity. Prior to harvesting, cultures were checked to ensure purity. The organisms were harvested by concentration in a Sharples centrifuge, followed by sedimentation at 27,000 x g and 0°C in a Sorvall RC2B centrifuge. The sediment was washed in cold phosphate-buffered saline (0.2 M, pH 7.5) and lyophilized. Isotopic labeling was performed by growth of organisms in 100 ml of medium supplemented with 5 ,uCi of [2-'4C]mevalonic acid (specific activity, 20 mCi/ mmol), 2.5 MCi of [1-'4C]oleic acid (specific activity, 30 mCi/mmol), or 500,Ci of [32P]orthophosphate (carrier-free). Extraction of lipids and lipopolysaccharides.Lipids were extracted from lyophilized cells by stirring with 40 volumes of chloroform-methanol (2:1, vol/vol) at room temperature for 60 min. Methods for further purification and separation into major classes have been documented previously (10). The lipopolysaccharides were ex...

Detection of lipoglycans in ureaplasmas

“…The facts that ureaplasmal lipoglycans are constituted primarily of glucose and mannose and that this capsular material binds the glucose-mannose-specific lectin concanavalin A support this supposition. With regard to composition, the lipoglycans from ureaplasmas resemble this polymer from A. oculi by containing only neutral but no amino sugars (3). They also possess a similarity to the lipoglycan from A. axanthum by possessing phosphorus (22).…”

Induction of procoagulant activity in human leukocytes with lipoglycans from mycoplasmas

“…Lipoglycans from three species of Acholeplasma (A. axanthum [bovine], A. oculi [caprine], and A. granularum [swine]) and from two serotypes of U. urealyticum (strain P108, serotype 3, and strain 681, serotype 4) were samples from lots of lipoglycans used in previous studies (1,(8)(9)(10). All were highly purified and free of detectable nucleic acids and protein.…”