Evidence for glycosyl-phosphatidylinositol anchoring of Toxoplasma gondii major surface antigens

1989 ◽  
Vol 9 (10) ◽  
pp. 4576-4580
Author(s):  
S Tomavo ◽  
R T Schwarz ◽  
J F Dubremetz
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Toxoplasma Gondii ◽  
Phospholipase C ◽  
Surface Antigens ◽  
Water Soluble ◽  
Radioactive Label ◽  
Glycosyl Phosphatidylinositol ◽  
Major Surface

The four major surface antigens of Toxoplasma gondii tachyzoites (P43, P35, P30, and P22) were made water soluble by phosphatidylinositol-specific phospholipase C (PI-PLC). These antigens were biosynthetically labeled with 3H-fatty acids, [3H]ethanolamine, and [3H]carbohydrates. Treatment of 3H-fatty-acid-labeled parasite lysates with PI-PLC removed the radioactive label from these antigens. A cross-reacting determinant was exposed on these antigens after PI-PLC treatment.

scholarly journals Evidence for glycosyl-phosphatidylinositol anchoring of Toxoplasma gondii major surface antigens.

1989 ◽  
Vol 9 (10) ◽  
pp. 4576-4580 ◽  
Author(s):  
S Tomavo ◽  
R T Schwarz ◽  
J F Dubremetz
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Toxoplasma Gondii ◽  
Phospholipase C ◽  
Surface Antigens ◽  
Water Soluble ◽  
Radioactive Label ◽  
Glycosyl Phosphatidylinositol ◽  
Major Surface

The four major surface antigens of Toxoplasma gondii tachyzoites (P43, P35, P30, and P22) were made water soluble by phosphatidylinositol-specific phospholipase C (PI-PLC). These antigens were biosynthetically labeled with 3H-fatty acids, [3H]ethanolamine, and [3H]carbohydrates. Treatment of 3H-fatty-acid-labeled parasite lysates with PI-PLC removed the radioactive label from these antigens. A cross-reacting determinant was exposed on these antigens after PI-PLC treatment.

THE BIOSYNTHESIS OF LONG-CHAIN FATTY ACIDS IN THE DEVELOPING CASTOR BEAN

1965 ◽  
Vol 43 (1) ◽  
pp. 49-62 ◽  
Author(s):  
D. T. Canvin
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Ricinoleic Acid ◽  
Castor Bean ◽  
Diethyl Malonate ◽  
Water Soluble ◽  
Long Chain Fatty Acids ◽  
Long Chain ◽  
Chain Fatty Acids

Acetate-1-C14 and acetate-2-C14 were supplied to slices of developing castor bean endosperm. The molecules were extensively incorporated into long-chain fatty acids, water-soluble compounds, and protein. Oleic acid was the fatty acid initially labelled from acetate and it was the precursor of ricinoleic acid. Aerobic conditions were required for the formation of oleic acid and for the conversion of oleic acid to ricinoleic acid. Under anaerobic conditions the incorporation of acetate carbon into fatty acids was inhibited more than 90% and almost all of the C14 was found in stearic and palmitic acids. Stearic acid appeared to be formed first and palmitic acid appeared to be derived from it through a shortening of the chain. The position of linoleic acid in the fatty acid interconversions was not clear except that it was not a free intermediate in the conversion of oleic acid to ricinoleic acid.Malonate-C14 was only absorbed slightly by the tissue and although absorption could be increased by the use of diethyl malonate the metabolism of the compound was not facilitated. Because of its poor utilization by the tissue the role of malonate in long-chain fatty acid synthesis in this tissue could not be ascertained.

Studies on the production of volatile fatty acids from grass by rumen liquor in an artificial rumen: III. A note on the volatile fatty acid production from crude fibre and grass cellulose

1957 ◽  
Vol 49 (2) ◽  
pp. 180-183 ◽  
Author(s):  
A. John ◽  
G. Barnett ◽  
R. L. Reid
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Acid Production ◽  
Volatile Fatty Acid ◽  
Volatile Fatty Acids ◽  
Relative Yield ◽  
Water Soluble ◽  
Cellulose Powder ◽  
Crude Fibre ◽  
Fatty Acid Production

1. The findings presented in two previous papers on the yields of volatile fatty acids, obtained by the action of rumen liquor in the artificial rumen, from fresh grass, dried grass and the water-soluble and water-insoluble separates of the latter, have been amplified by a consideration of the acids similarly obtained from specimens of chemically prepared crude fibre and cellulose, from four of the dried grass specimens.2. The proportions of different volatile fatty acids from grass crude fibre and grass cellulose resemble those obtained from cellulose powder, propionic acid being produced in greatest relative yield.3. A general review of these latter findings, in relation to those already presented, has been given.

scholarly journals A continuous fluorescence-displacement assay for triacylglycerol lipase and phospholipase C that also allows the measurement of acylglycerols

1991 ◽  
Vol 276 (1) ◽  
pp. 129-133 ◽  
Author(s):  
D C Wilton
Keyword(s):  
Fatty Acids ◽  
Enzyme Activity ◽  
Fatty Acid ◽  
Phospholipase C ◽  
Initial Rate ◽  
Long Chain Fatty Acids ◽  
Triacylglycerol Lipase ◽  
Displacement Assay ◽  
Long Chain ◽  
Chain Fatty Acids

A new continuous fluorescence-displacement assay for enzymes that release long-chain fatty acids [Wilton (1990) Biochem. J. 266, 435-439] is described in detail for pig pancreatic triacylglycerol lipase. The assay involves the displacement of the highly fluorescent fatty acid probe 11-(dansylamino)undecanoic acid from rat liver fatty acid-binding protein by long-chain fatty acids released as a result of enzyme activity. The assay is surprisingly effective for triacylglycerol lipase, allowing the expression of full activity with low concentrations of substrates in the absence of detergents. The initial rate of decrease in fluorescence is linearly related to enzyme concentration, and activity can be detected in the assay down to concentrations of 10 pg of pure enzyme/ml. The assays demonstrated the quantitative conversion of limiting amounts of substrate into the monacylglycerol. This observation allowed the assay to be used to measure substrates such as triacylglycerols and particularly 1,2-diacylglycerols at concentrations down to about 0.1 microM. Because phospholipase C releases 1,2-diacylglycerols, the coupling of this enzyme to excess lipase allowed the measurement of pure phospholipase C from Bacillus cereus at concentrations down to about 2 ng/ml, and the initial rate of fall in fluorescence in the assay was linearly related to enzyme activity.

scholarly journals The effect of fatty acid surfactants on the uptake of nitric acid to deliquesced NaCl aerosol

2008 ◽  
Vol 8 (1) ◽  
pp. 687-725 ◽  
Author(s):  
K. Stemmler ◽  
A. Vlasenko ◽  
C. Guimbaud ◽  
M. Ammann
Keyword(s):  
Boundary Layer ◽  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Nitric Acid ◽  
Organic Compounds ◽  
Marine Boundary Layer ◽  
Water Soluble ◽  
Chemical Inhomogeneity ◽  
Uptake Coefficient

Abstract. Surface active organic compounds have been observed in marine boundary layer aerosol. Here, we investigate the effect such surfactants have on the uptake of nitric acid (HNO3), an important removal reaction of nitrogen oxides in the marine boundary layer. The uptake of gaseous HNO3 on deliquesced NaCl aerosol was measured in a flow reactor using HNO3 labelled with the short-lived radioactive isotope 13N. The uptake coefficient γ on pure deliquesced NaCl aerosol was γ=0.5±0.2 at 60% relative humidity and 30 ppb HNO3(g). The uptake coefficient was reduced by a factor of 5–50 when the aerosol was coated with saturated linear fatty acids with carbon chain lengths of 18 and 15 atoms in monolayer quantities. In contrast, neither shorter saturated linear fatty acids with 12 and 9 carbon atoms, nor coatings with the unsaturated oleic acid (C18, cis-double bond) had a detectable effect on the rate of HNO3 uptake. It is concluded that it is the structure of the monolayers formed, which determines their resistance towards HNO3 uptake. Fatty acids (C18 and C15), which form a highly ordered film in the so-called liquid condensed state, represent a significant barrier towards HNO3 uptake, while monolayers of shorter-chain fatty acids (C9, C12) and of the unsaturated oleic acid form a less ordered film in the liquid expanded state and do not hinder the uptake. Similarly, high contents of humic acids in the aerosol, a structurally inhomogeneous, quite water soluble mixture of oxidised high molecular weight organic compounds did not affect HNO3 uptake. As surfactant films on naturally occurring aerosol are expected to be less structured due to their chemical inhomogeneity, it is likely that their inhibitory effect on HNO3 uptake is smaller than that observed here for the C15 and C18 fatty acid monolayers.

scholarly journals The structure of a major surface antigen SAG19 from Eimeria tenella unifies the Eimeria SAG family

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Nur Zazarina Ramly ◽  
Samuel R. Dix ◽  
Sergey N. Ruzheinikov ◽  
Svetlana E. Sedelnikova ◽  
Patrick J. Baker ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Neospora Caninum ◽  
Sequence Similarity ◽  
Surface Antigens ◽  
Eimeria Tenella ◽  
Besnoitia Besnoiti ◽  
Sequence Comparisons ◽  
Host Interactions ◽  
Apicomplexan Parasites ◽  
Major Surface

AbstractIn infections by apicomplexan parasites including Plasmodium, Toxoplasma gondii, and Eimeria, host interactions are mediated by proteins including families of membrane-anchored cysteine-rich surface antigens (SAGs) and SAG-related sequences (SRS). Eimeria tenella causes caecal coccidiosis in chickens and has a SAG family with over 80 members making up 1% of the proteome. We have solved the structure of a representative E. tenella SAG, EtSAG19, revealing that, despite a low level of sequence similarity, the entire Eimeria SAG family is unified by its three-layer αβα fold which is related to that of the CAP superfamily. Furthermore, sequence comparisons show that the Eimeria SAG fold is conserved in surface antigens of the human coccidial parasite Cyclospora cayetanensis but this fold is unrelated to that of the SAGs/SRS proteins expressed in other apicomplexans including Plasmodium species and the cyst-forming coccidia Toxoplasma gondii, Neospora caninum and Besnoitia besnoiti. However, despite having very different structures, Consurf analysis showed that Eimeria SAG and Toxoplasma SRS families each exhibit marked hotspots of sequence hypervariability that map to their surfaces distal to the membrane anchor. This suggests that the primary and convergent purpose of the different structures is to provide a platform onto which sequence variability can be imposed.

Action of phospholipases A2 and C on free fatty acid release during complete ischemia in rat neocortex

1992 ◽  
Vol 76 (4) ◽  
pp. 648-651 ◽  
Author(s):  
Atsushi Umemura ◽  
Hideo Mabe ◽  
Hajime Nagai ◽  
Fumihiko sugino
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Free Fatty Acids ◽  
Phospholipase C ◽  
Phenylmethylsulfonyl Fluoride ◽  
Content Type ◽  
Rat Neocortex ◽  
Fatty Acid Release ◽  
Acid Release

✓ The levels of brain free fatty acids rapidly increase after the onset of ischemia. The purpose of this study was to investigate the action of phospholipases A2 and C during complete ischemia based on the effects of a phospholipase C inhibitor (phenylmethylsulfonyl fluoride) and the N-methyl-D-aspartate antagonist MK-801 on the release of free fatty acids in rat neocortex. Complete brain ischemia was induced in rats with cardiac arrest by intracardiac injection of KC1. Free fatty acid levels in the neocortex were measured 0, 2, 4, and 8 minutes after cardiac arrest. Phenylmethylsulfonyl fluoride inhibited the release of free fatty acids primarily from phosphatidylinositol during the first 2 minutes of ischemia and from phosphatidylcholine and phosphatidylethanolamine at 4 to 8 minutes of ischemia. Conversely, MK-801 inhibited free fatty acid release mainly from phosphatidylcholine and phosphatidylethanolamine at 2 to 4 minutes of ischemia. These results indicate that the release of free fatty acids during the first 2 minutes of ischemia can be attributed mostly to the action of phospholipase C, and that the activation of phospholipase C further influences the activation of phospholipase A2 in the subsequent course, while phospholipase A2 predominantly acts after 2 minutes of ischemia.

Oxidative stability of buttermilk as influenced by the fatty acid composition of cows' milk manipulated by diet

2004 ◽  
Vol 71 (1) ◽  
pp. 46-50 ◽  
Author(s):  
Dorthe Kristensen ◽  
Rikke V Hedegaard ◽  
Jacob H Nielsen ◽  
Leif H Skibsted
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Lipid Oxidation ◽  
Acid Composition ◽  
Unsaturated Fatty Acids ◽  
Radical Scavenging ◽  
Water Soluble ◽  
Lipid Hydroperoxides ◽  
Lipid Oxidation Products

Milk from cows fed a low-fat diet high in cereals designed to stimulate fat synthesis de novo was lower in unsaturated fatty acids (21·3%) than milk from cows fed a diet high in fat, mainly from roasted soy beans (41·3% unsaturated fatty acids). Buttermilk from the more unsaturated milk was less oxidatively stable during storage (at 4 °C, followed for 11 d) than buttermilk from the more saturated milk, as monitored both by primary lipid oxidation products (lipid hydroperoxides) and by the secondary lipid oxidation product, hexanal. Fat-soluble antioxidants, β-carotene and α-tocopherol, analysed by HPLC, were not consumed during storage for either of the two types of buttermilk. In contrast, the antioxidative capacity of the serum phase decreased during storage as evaluated in a radical scavenging assay based on the semi-stable water-soluble radical nitrosodisulphonate (Fremy's salt). The time course for the decrease in water-soluble antioxidants was very similar for the two types of buttermilk suggesting that oxidation is initiated in the serum phase independently of fatty acid composition.

scholarly journals Developmentally regulated, phospholipase C-mediated release of the major surface glycoprotein of amastigotes of Trypanosoma cruzi.

1988 ◽  
Vol 167 (2) ◽  
pp. 300-314 ◽  
Author(s):  
N W Andrews ◽  
E S Robbins ◽  
V Ley ◽  
K S Hong ◽  
V Nussenzweig
Keyword(s):  
Trypanosoma Cruzi ◽  
Phospholipase C ◽  
Myristic Acid ◽  
Surface Glycoprotein ◽  
Developmentally Regulated ◽  
African Trypanosomes ◽  
Glycosyl Phosphatidylinositol ◽  
Major Surface Glycoprotein ◽  
Major Stage ◽  
Major Surface

The surface of amastigotes of Trypanosoma cruzi is covered by Ssp-4, a major stage-specific glycoprotein. Ssp-4 is anchored to the cell membrane by GPI. It can be metabolically labeled with [3H]myristic acid, and is converted into a hydrophilic form by treatment with the glycan-specific phospholipase C of T. brucei, or after lysis of the parasites in non-ionic detergents. The hydrophilic form of Ssp-4 is recognized by antibodies to the cross-reactive determinant of the variant surface glycoprotein of African trypanosomes. Ssp-4 is progressively shed during the intra- or extracellular development of amastigotes preceding their transformation into epi- and trypomastigotes. We show here that T. cruzi contains a phospholipase C and that most shed Ssp-4 is hydrophilic, does not contain myristic acid, and reacts with anti-CRD. These observations provide strong evidence that phospholipase C mediates the release of this glycosyl-phosphatidylinositol-anchored protein under physiological conditions, as the parasite undergoes differentiation.

Sign in / Sign up

Export Citation Format

Share Document