Release of arachidonic acid from human endometrial cells in culture mediated by calcium ionophore (A23187) or fluoride.

Primary cultures of endometrial glands and stromal cells were labelled with [14C]-arachidonic acid for 4 h before exposure to either the calcium ionophore, A23187 (which activates phospholipase A2 (PLA2) by increasing intracellular calcium concentrations) or sodium fluoride (which activates a G-protein). Calcium ionophore (0.5-50 mumol/l) stimulated a dose- and time-dependent release of arachidonic acid from endometrial glands. Incubation with ionophore (10 mumol/l) for 1 h released 22% of the incorporated arachidonic acid. There was a corresponding decrease in phospholipids and no loss from triglycerides. Stromal cells were unresponsive to ionophore. Fluoride (10 mmol/l) stimulated a release of arachidonic acid from stromal cells and endometrial glands (6.5% of the total arachidonic acid incorporated). In stromal cells, arachidonic acid was released from triglycerides in Day-1 cultures and from phospholipids in Day-2 cultures. In both Day-1 and Day-2 cultures of endometrial glands, arachidonic acid was released from phospholipids, but not from triglycerides. Among the phospholipids, phosphatidylcholine was always the major source of arachidonic acid. Arachidonic acid release from endometrial glands and stromal cells may be mediated by activation of PLA2 (or phospholipase C) via a G-protein, but in glands calcium ionophore may have a direct effect on PLA2. The response to calcium ionophore may reflect the differences in calcium requirements of the two endometrial PLA2 isoenzymes.     

Large Alterations in Ganglioside and Neutral Glycosphingolipid Patterns in Brains from Cases with Infantile Neuronal Ceroid Lipofuscinosis/Polyunsaturated Fatty Acid Lipidosis

Lipid composition was studied on cerebral tissue from nine children who had died of a progressive encephalopathy called the infantile form of neuronal ceroid lipofuscinosis (INCL) or polyunsaturated fatty acid lipidosis (PFAL). In the terminal stage of the disease, the concentrations of all lipid classes were found to be significantly reduced in the cerebral and cerebellar cortex and white matter. The concentration of gangliosides of the cerebral cortex was 15% and that of cerebrosides (galactosylceramide) in white matter 0.2-5% of the normal values for the children's ages. The reduction of gangliosides mainly affected those of the gangliotetraose series, particularly GD1a. The fatty acids of the linolenic acid series were strongly reduced in ethanolamine and serine phosphoglycerides. A very large increase up to 100-fold of oligoglycosphingolipids of the globo series and two fucose-containing lipids of the neolacto series was found in the forebrain of the three advanced cases examined. The brain tissue also contained very high concentrations of mono-, di-, and trisialogangliosides of the lacto and neolacto series, gangliosides with type 1 chain dominating. The structures of the gangliosides were tentatively identified by gas chromatography-mass spectrometry and monoclonal antibodies with carefully determined epitope specificity. The gangliosides and neutral glycosphingolipids had very similar fatty acid composition, consisting of about 40% stearic acid and 40% C24-acids.     

Purification, characterization and immunological properties of the serotype-specific capsular polysaccharide of Pasteurella haemolytica serotype A7 organisms

The serotype-specific capsular polysaccharide from two strains of Pasteurella haemolytica serotype A7 organisms was purified and characterized by chemical analysis and by 1H and 13C NMR spectroscopy using one- and two-dimensional methods. The polymer has the repeating unit----3)-beta-2-acetamido-2-deoxygalactopyranose-(1----3)-alpha- 2-acetamido- 2-deoxy-6-O-acetyl-glucopyranose-(1-phosphate----. It was immunogenic (capable of eliciting antibodies) for sheep. Chemical removal of O-acetyl groups destroyed both the ability of the polymer to adhere to sheep erythrocytes at neutral pH and the ability to form immune precipitates with specific antisera. Studies using the protein A-gold technique in the electron microscope showed the polysaccharide to be peripherally localized on the bacterial surface.     

Congo Red-Agar Plating Medium for Detecting Pigmentation in Pasteurella pestis

Ability to detect pigmented and nonpigmented Pasteurella pestis is essential in plague research, and is currently dependent on use of the synthetic hemin-agar of Jackson and Burrows. We have devised a new differential medium for this purpose, containing Congo red dye and common, commercially available laboratory media. The ease and simplicity of preparation make the Congo red-agar a practical routine laboratory tool in plague research. These findings, possibly indicating a common binding site for hematin and Congo red, should be useful in efforts to determine the chemical nature of a bacterial component associated with high virulence in P. pestis.