Molecular species of mono-, di-, and triphosphoinositides of bovine brain

The mono-, di-, and triphosphoinositides of bovine brain were isolated by chromatography on columns of DEAE-cellulose, alumina, and silicic acid. The major molecular species in each phosphoinositide class were identified and quantitatively estimated by combined thin-layer and gas-liquid chromatography of the component diglycerides, which were released by hydrolysis with a specific brain phosphodiesterase. The diglycerides were treated with pancreatic lipase, and the positional distribution of the fatty acids was determined. Over 27 molecular species were identified, and these accounted for about 95% of each phosphoinositide class, but the 1-stearate 2-arachidonate derivative contributed more than 40% of the total in each class. The other molecular species also were qualitatively and quantitatively similar in the three phosphoinositide classes. All the long-chain and polyunsaturated acids were confined to the 2-position and were preferentially paired with stearic acid in the 1-position. Oleic acid in the 2-position was about equally divided between species with palmitic and stearic acids in the 1-position. These results suggest that the mono-, di-, and triphosphoinositides of the bovine brain have similar compositions and that the various molecular species may be metabolically related.     

Characterization of mono-, di-, and tri-O-acetylated sialic acids on human cells

The presence of mono-, di-, and tri-O-acetylated sialic acids on human cells was demonstrated by using radiochromatographic and chemical techniques. Human melanoma cells and fresh colon tissue were biosynthetically labeled with 6- (3H) glucosamine. Radiolabeled sialic acids were hydrolytically removed from cellular glycoconjugates, purified by ion-exchange chromatography, and separated by paper chromatography on the basis of the number of O-substitutions on each sialic molecule. This analytical technique characterized radiolabeled sialic acids that migrated with the same Rf as synthetic mono-, di-, and tri-O-acetylated 14C-labeled sialic acids. The mono-O-acetylated sialic acids were characterized by their sensitivity to sodium periodate oxidation and a crude mouse liver esterase preparation. The di- and tri-O-acetylated sialic acids were characterized by their resistance to sodium periodate oxidation and sensitivity to the action of crude mouse liver esterase. Chromatographically separated di- and tri-O-acetylated sialic acids from normal human colon tissue were characterized by their respective ion molecular weights by using fast-atom bombardment-mass spectrometry. Using these methods, we chemically characterized mono, di-, and tri-O-acetylated sialic acids expressed on human cells. Aberrant expression of O-acetylated sialic acids was associated with adenocarcinoma of the colon, leading to a nearly complete loss of di- and tri-O-acetylated sialic acids.     

Mutagenicity of mono-, di- and tri-nitropyrenes in Chinese hamster ovary cells

1-Nitropyrene (1-NP), 1,3-dinitropyrene (1,3-DNP), 1,6-dinitropyrene (1,6-DNP), 1,8-dinitropyrene (1,8-DNP) and 1,3,6-trinitropyrene (1,3,6-TNP) were tested for mutagenicity in cultured Chinese hamster ovary (CHO) cells. Mutation at the hypoxanthine-guanine phosphoribosyl transferase gene locus was quantified. While 1-NP and 1,3-DNP had only marginal direct-acting mutagenicity, 1,6-DNP, 1,8-DNP and 1,3,6-TNP showed definite mutagenicity, with specific mutagenic activities of 8.1, 21 and 54 mutants/10⁶ survivors/μg·ml⁻¹ respectively. The mutagenicity of 1-NP increased with increasing concentrations of Aroclor-1254 induced liver homogenate (S9) in the treatment medium. However, S9 at all concentrations tested decreased the mutagenicity of 1,6-DNP and 1,8-DNP. S9 at low concentrations enhanced the mutagenicity of 1,3-DNP and 1,3,6-TNP and that at high concentrations decreased their mutagenicity. The positive mutagenic response of the nitropyrenes suggests that they are potentially carcinogenic, and that further research into their possible human health risk should be performed.     

Mutagenicity of mono-, di- and tri-nitropyrenes in Chinese hamster ovary cells

1-Nitropyrene (1-NP), 1,3-dinitropyrene (1,3-DNP), 1-6-dinitropyrene (1,6-DNP), 1,8-dinitropyrene (1,8-DNP) and 1,3,6-trinitropyrene (1,3,6-TNP) were tested for mutagenicity in cultured Chinese hamster ovary (CHO) cells. Mutation at the hypoxanthine-guanine phosphoribosyl transferase gene locus was quantified. While 1-NP and 1,3-DNP had only marginal direct-acting mutagenicity, 1,6-DNP, 1,8-DNP and 1,3,6-TNP showed definite mutagenicity, with specific mutagenic activities of 8.1, 21 and 54 mutants/10(6) survivors/micrograms . ml-1 respectively. The mutagenicity of 1-NP increased with increasing concentrations of Aroclor-1254 induced liver homogenate (S9) in the treatment medium. However, S9 at all concentrations tested decreased the mutagenicity of 1,6-DNP and 1,8-DNP. S9 at low concentrations enhanced the mutagenicity of 1,3-DNP and 1,3,6-TNP and that at high concentrations decreased their mutagenicity. The positive mutagenic response of the nitropyrenes suggests that they are potentially carcinogenic, and that further research into their possible human health risk should be performed.     

Antibacterial activities of mono-, di- and tri-substituted triphenylamine-based phosphonium ionic liquids

We report the synthesis of new mono, di and tri phosphonium ionic liquids and the evaluation of their antibacterial activities on both Gram-positive and Gram-negative bacteria from the ESKAPE-group. Among the molecules synthesized some of them reveal a strong bactericidal activity (MIC?=?0.5?mg/L) for Gram-positive bacteria (including resistant strains) comparable to that of standard antibiotics. A comparative Gram positive and Gram negative antibacterial activities shows that the nature of counter-ion has no significant effects. Interestingly, the increase of phosphonium lateral chains (from 4 to 8 carbons) results in a decrease of antibacterial activities. However, the increase of the spacer length has a positive influence on the activity on both Gram-positive and Gram-negative bacteria except for E. aerogenes. Finally, the increased charge density has no effect on the Gram-positive antibacterial activities (MIC between 2 and 4?mg/L) but seems to attenuate (except for P. aeruginosa) the discrimination between Gram-positive and Gram-negative. Overall these results suggest a unique mechanism of action of these triphenylamine-phosphonium ionic liquid derivatives.     

Separation of common nucleotides,mono-, di- and triphosphates,by capillary electrophoresis

A capillary electrophoretic procedure for the separation of eleven nucleotides, 5′-mono-, di- and triphosphates of adenosine, guanosine, cytidine and uridine, has been developed. All eleven analytes can be separated in a fused-silica capillary (63 cm to the detector, I.D. 75 μm) at 20 kV in a 0.02 mol l⁻¹ phosphate-borate buffer (pH 8.0–9.0) with a separation factor ⩾1. The values of the Offord parameter calculated for individual nucleotides predict that monophosphates will migrate faster than triphosphates, and in turn triphosphates will precede diphosphates. By analogy, faster electroosmotic mobility (lower electromigration) of purine nucleotides (AP, GP) can be explained by a more voluminous structure of purine derivatives (two aromatic rings as compared to pyrimidines). Generally speaking, all compounds separated follow the Offord equation assuming that the triphosphate derivatives are ionized to the third degree forming HL³⁻ anions. This assumption is in agreement with the current knowledge about protolytic equilibria of polyphosphates. The only exception to this rule is faster migration of guanosine-5′-triphosphate (GTP) preceding uridine-5′-monophosphate (UMP) which is ascribed in part to the larger molecule of GTP and the two additional OH-groups bound to the pyrimidine ring of UMP.     

Synthesis,photophysical properties and photocytotoxicity of mono-, di-, tri- and tetra-glucosylated fluorophenylporphyrins

In order to explore the effect of substitution patterns on the photocytotoxicity of glycoconjugated porphyrins, we synthesized and characterized a ‘complete set’ of tetrakis(perfluorophenyl)porphyrins having β-d-glucopyranosylthio groups on the phenyl ring. Among five possible derivatives, trans-substituted S-glucosylated porphyrin trans-2_OH exerted outstanding photocytotoxicity (EC₅₀ value was <5 nM) in HeLa cells. The excellent photocytotoxicity of trans-2_OH was found to be attributable to several factors, namely high optical transition probability in aqueous media, efficient type I photoreactions and enhanced cellular uptake.     

Chemical structures of mono-, di-, tri- and tetraglycosyl glycerides in rice bran

• 1.1. Monoglycosyl monoglyceride, mono-, di-, tri- and tetraglycosyl diglycerides were isolated from rice bran and characterized for their chemical structures.
• 2.2. Monoglycosyl monoglycerides were characterized as Gal(β1' → 3)-1- or 2-monoacyl-sn-glycerol and Glc(β1' → 3)-1- or 2-monoacyl-sn-glycerol.
• 3.3. The structures ofmonoglycosyl diglyceride were Gal(β1' → 3)-1,2-diacyl-sn-glycerol and Glc(β1' → 3)-1,2-diacyl-sn-glycerol. Epimeric separation of the galactosyl and glucosyl glycerides was for the first time achieved by thin-layer chromatography.
• 4.4. The main diglycosyl diglyceride was shown to be Gal(α1' → 6')-Gal(β1' → 3)-1,2-diacyl-sn-glycerol.
• 5.5. The major structure of triglycosyl diglyceride was characterized as Gal(α1″' → 6″)-Gal(α1″ → 6')-Gal(β1' → 3)-1,2-diacyl-sn-glycerol.
• 6.6. The representative structure of tetraglycosyl diglyceride was for the first time established as Gal(α1″ → 6″')-Gal(α1″' α 6″)-Gal(α1″ → 6')-Gal(βl' → 3)-1, 2-diacyl-sn-glycerol.

     

Gas chromatographic analysis of synthetic glycidol esters, mono-, di- and triglycerides.

The gas chromatographic analysis of glycidol esters and mono-, di-,and triglycerides of palmitic-, stearic-, and oleic acid mixtures is described. The composition of the products was determined by gas chromatography on OV-17 after trimethylsilylation. Base-line separations between 1- and 2-monoglycerides and between 1,2- and 1,3-diglycerides were obtained. Isomerisation of the trimethylsilyl ethers of monoglycerides was not observed, contrary to published work.     

Degradation of mono-, di-, and trihalogenated benzoic acids by Pseudomonas aeruginosa JB2

Pseudomonas aeruginosa JB2 was isolated from a polychlorinated biphenyl-contaminated soil by enrichment culture containing 2-chlorobenzoate as the sole carbon source. Strain JB2 was subsequently found also to grow on 3-chlorobenzoate, 2,3- and 2,5-dichlorobenzoates, 2,3,5-trichlorobenzoate, and a wide range of other mono- and dihalogenated benzoic acids. Cometabolism of 2,4-dichlorobenzoate was also observed. Chlorocatechols were the central intermediates of all chlorobenzoate catabolic pathways. Degradation of 2-chlorobenzoate was routed through 3-chlorocatechol, whereas 4-chlorocatechol was identified from the metabolism of both 2,3- and 2,5-dichlorobenzoate. The initial attack on chlorobenzoates was oxygen dependent and most likely mediated by dioxygenases. Although plasmids were not detected in strain JB2, spontaneous mutants were detected in 70% of glycerol-grown colonies. The mutants were all of the following phenotype: benzoate+, 3-chlorobenzoate+, 2-chlorobenzoate-, 2,3-dichlorobenzoate-, 2,5-dichlorobenzoate-. While chlorocatechols were oxidized by the mutants at wild-type levels, oxidation of 2-chloro- and 2,3- and 2,5-dichlorobenzoates was substantially diminished. These findings suggested that strain JB2 possessed, in addition to the benzoate dioxygenase, a halobenzoate dioxygenase that was necessary for the degradation of chlorobenzoates substituted in the ortho position.     

Cation binding to membranes: Competition between mono-, di- and trivalent cations

The binding of mono-, di- and trivalent cations to negatively charged surfaces is studied within the framework of a modified Gouy-Chapman equation. For any given combination of ions of the above valences, the existence and uniqueness of the solution for the surface potential is shown. The treatment provides the surface potential and charge density. For a system containing only monovalent and divalent ions, analytical solutions are given. When trivalent ions are also present, a procedure based on numerical integration is described. The distance dependence of the electrostatic potential for planar surfaces is given. The calculations provide the amount of cations tightly bound and the amount trapped in the double layer region. The competition between cations for binding to surfaces is elucidated.     

Chemical structures of mono-, di-, tri-, and tetraglycosyl glycerides in rice bran.

1. Monoglycosyl monoglyceride, mono-, di-, tri- and tetraglycosyl diglycerides were isolated from rice bran and characterized for their chemical structures. 2. Monoglycosyl monoglycerides were characterized as Gal(beta 1' leads to 3)-1- or 2-monoacyl-sn-glycerol and Glc(beta 1' leads to 3)-1- or 2-monoacyl-sn-glycerol. 3. The structures of monoglycosyl diglyceride were Gal(beta 1' leads to 3)-1,2-diacyl-sn-glycerol and Glc(beta 1' leads to 3)-1,2diacyl-sn-glycerol. Epimeric separation of the galactosyl and glucosyl glycerides was for the first time achieved by thin-layer chromatography. 4. The main diglycosyl diglyceride was shown to be Gal(alpha 1' leads to 6')-Gal(beta 1' leads to 3)-1,2-diacyl-sn-glycerol. 5. The major structure of triglycosyl diglyceride was characterized as Gal(alpha 1' leads to 6')-Gal(alpha 1' leads to 6')-Gal(beta 1' leads to 3)-1,2-diacyl-sn-glycerol. 6. The representative structure of tetraglycosyl diglyceride was for the first time established as Gal(alpha 1' leads to 6')-Gal(alpha 1' leads to 6')-Gal(a-pha 1' leads to 6')-Gal(beta1' leads to 3)-1,2-diacyl-sn-glycerol.     

Characterization of mono-, di- and triacylglycerol lipase activities in the isolated rat heart

The lipolytic activities of heart tissue towards full and partial acylglycerols were characterized. Tissue lysosomal, acid lipase activity (pH 4.8) was inhibited by high salt, protamine sulfate, NaF, MgATP, Triton X-100, serum and the esterase-inhibitor diethylparanitrophenyl phosphate. The tissue neutral triacylglycerol lipase activity (pH 7.4) was recovered predominantly in the microsomal and soluble fractions and exhibited essentially identical properties towards activators (serum, apolipoprotein C-II) and reagents (NaCl, Triton X-100, NaF, MgATP and diethylparanitrophenyl phosphate) relative to vascular lipoprotein lipase, except for protamine sulfate which increased the serum-stimulated neutral triacylglycerol lipase activity. Triacylglycerol hydrolysis at acid pH was incomplete, whereas at neutral pH full hydrolysis occurred. Myocardial mono- and diacylglycerol lipase activities, with pH optima of 8.0 and 7.4, respectively, were recovered in the microsomal fraction. They differed immunologically from neutral lipase and lipoprotein lipase and did not bind to heparin-Sepharose 4B. They were kinetically different, partially inhibited by NaCl and differentially affected by protamine sulfate. NaF, Triton X-100 and diethylparanitrophenyl phosphate. Our data suggest that endogenous hydrolytic activity against full and partial acylglycerols is mediated by separate enzymes.     

Separation of mono-, di-, and trihydroxy stereoisomers of bile acids by capillary gas-liquid chromatography

Capillary gas-liquid chromatographic separation was studied for the complete set of the 26 theoretically possible isomers of mono-, di-, and trihydroxylated 5 beta-cholanic acids, which differ from one another in the number, position, and configuration of hydroxyl groups at C-3, C-7, and/or C-12 in the nucleus, as well as for some of their related acids. The bile acid samples were chromatographed as their methyl ester-trimethylsilyl (TMSi) ether derivatives and analyzed on three capillary columns coated with nonpolar OV-1, slightly polar OV-17, and polar SP-2340 as liquid phases. The retention times on capillary gas-liquid chromatography (GLC) responded dramatically to the minor structural differences, and almost complete separation of the positional and stereochemical isomers was achieved by the combined use of SP-2340 and OV-17 (or OV-1) capillary columns.