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PubMed1977

Detection of bacterial metabolites in spent culture media and body fluids by electron capture gas-liquid chromatography.

Electron capture gas-liquid chromatography, when used to analyze derivatized extracts of spent culture media and body fluids under specified conditions, holds promise as a tool for use by physicians, hospitals, and clinical laboratories in identifying certain diseases and disease-producing organisms. The detection of certain disease processes and the identification of disease-producing organisms are based on qualitative or large quantitative differences in EC-GLC profiles or a combination of both. Various practical procedures are given for extracting and derivatizing compounds, such as carboxylic acids, hydroxy acids, alcohols, amines, and nitrosamines. The characteristics of the parameters essential for successful analysis are discussed. Species and, in some cases, strains have been differentiated by comparing EC-GLC profiles. Metabolic products are affected by change in substrate. Media that can be reproduced from lot to lot are essential in some studies. The volatile components detected by EC-GLC in spent culture media consist mostly of bacterial metabolites, but the volatile compounds detected in body fluids may be bacterial metabolites, volatile components produced by the host in response to an infection, metabolites of cells associated with host defense, or a combination of two or more of these groups of compounds. The EC-GLC profiles obtained by analysis of synovial and cerebrospinal fluids appear to have good potential for use in diagnosing certain forms of arthritis and meningitis. Well-documented samples are essential to establishing EC-GLC profiles representative of a particular disease. A moderately priced computer would greatly aid in data processing and could be especially useful in compensating for minor changes in the retention times of peaks, which can occur as a result of column aging or when columns are renewed. An approach to the identification of components detected by EC-GLC, which makes use of electron capture gas chromatography-mass spectrometry, is presented.

Alcohols↗
PubMed1976

The effect of substitution of diaminopimelic acid by 4-hydroxy-diaminopimelic acid on the synthesis and degradation of murein in Escherichia coli 173-25.

Defects in the formation of the septum and gradually autolysis of cells occur when the dap-dependent mutant of Escherichia coli is grown in a medium with 4-hydroxy-diaminopimelic acid. When the culture grown in the presence of the labelled analogue is supplemented with the non-radioactive diaminopimelic acid a portion of the TCA-soluble radioactivity is released from the cells during 20 min after the addition of diaminopimelic acid. During this time interval the elongated forms formed in the presence of the analogue divide, however, only on the condition that the above forms are not irreversibly damaged. The increased concentration of the analogue in the medium substantially suppresses the irregularities in the development of the septum as well as the degradation of analogue containing cell wall. However, the growth rate in the presence of the analogue is always slightly lower than that in the presence of diaminopimelic acid. The cell wall pulse-labelled with diaminopimelic acid or its analogue for a time interval shorter than 1/4 of the generation time exhibits the same or only slightly higher rate of diaminopimelic acid is probably utilized less effectively for the synthesis of murein than diaminopimelic acid. However, its incorporation into the wall does not result in pronounced damage of the cell.

Cell Division↗
PubMed2025

Aminoacyl-tRNA Specificity of a Ligase Catalyzing Non-ribosomal Peptide Extension.

Peptide aminoacyl-transfer ribonucleic acid ligases (PEARLs) are amide-bond-forming enzymes that extend the main chain of peptides by using aminoacyl-tRNA (aa-tRNA) as a substrate. In this study, we investigated the substrate specificity of the PEARL BhaBCAla from Bacillus halodurans, which utilizes Ala-tRNAAla. By leveraging flexizyme, a ribozyme capable of charging diverse acids onto a desired tRNA, we generated an array of aa-tRNAs in which we varied both the amino acid and the tRNA to dissect the substrate scope of BhaBCAla. We demonstrate that BhaBCAla catalyzes peptide extension with noncognate proteinogenic and noncanonical amino acids, hydroxy acids, and mercaptocarboxylic acids when attached to tRNAAla. For most of these, the efficiency was considerably reduced compared to Ala, indicating that the enzyme recognizes the amino acid. By variation of the different parts of the tRNA, enzyme specificity was shown to also depend on the acceptor stem and the anticodon arm of the tRNA. These findings establish the molecular determinants of PEARL specificity and provide a foundation for engineering these enzymes for broader applications in peptide synthesis.

RNA, Transfer, Amino Acyl↗
PubMed1976

Synthesis and some pharmacological properties of [1-(L-2-hydroxy-3-mercaptopropanoic acid), 4-threonine]oxytocin (hydroxy [4-thr]oxytocin), a peptide with strikingly high oxytocic potency and of [1-(L-2-hydroxy-3-mercaptopropanoic acid)]oxytocin (hydroxy-oxytocin).

[1-(L-2-Hydroxy-3-mercaptopropanoic acid), 4-threonine]oxytocin (hydroxy[4-Thr]oxytocin) and [1-(l-2-hydroxy-3-mercaptopropanoic acid)]oxytocin (hydroxy-oxytocin) were synthesized by a combination of solid phase and classical methods of peptide synthesis. Protected octapeptides were synthesized by the solid-phase method and 1 + 8 couplings in solution were then employed to furnish the required key protected intermediates. Hydroxy[4-Thr]oxytocin has oxytocic potency as measured in the rat uterus suspended in a Mg2+-free solution, of about 4200 units/mg, eight times the potency of oxytocin, while its antidiuretic potency is approximately equal to that of oxytocin. It thus exhibits a significantly favorable oxytocic-antidiuretic sleectivity. Hydroxy-oxytocin has an oxytocic potency of approximatels 1300 units/mt, 2.5 times that of oxytocin. Threonine substitution in hydroxy-oxytocin has thus caused a significant enhancement in both oxytocic potency and selectivity. The enhancement in oxytocic potency of these two peptides relative to oxytocin and [4-Thr]oxytocin appears to correlate with their lipophilic characteristics, suggesting a significant role of lipophilicity in the interplay of oxytocin-like peptides with oxytocic receptors.

Animals↗
PubMedDate not supplied

The mechanism of adipocere formation 1. Identification and chemical properties of hydroxy fatty acids in adipocere.

The hydroxy fatty acid purified from the adipocere, m.p. 78.5 degrees -79.0 degrees C, was optically inactive and the adipocere contained about 3 to 20% hydroxy fatty acid of the total fatty acids. The melting point of the hydroxy fatty acid was nearly identical with that of the 10-D, L-hydroxyoctadecanoic acid synthesized organically, suggesting that the hydroxy fatty acid in the adipocere appears to be converted non-enzymatically. In the adipocere two hydroxy fatty acid components were detected by gas-liquid chromatography (GLC). The major and minor components were identified as 10-hydroxyoctadecanoic and 10-hydroxyhexadecanoic acids, respectively, by gas chromatography-mass spectrometry (GC-MS). These hydroxy fatty acids found in the adipocere appear to play an important role on the formation of adipocere.

Adipose Tissue↗
PubMed1979

The identification of 3-keto-2-methylvaleric acid and 3-hydroxy-2-methylvaleric acid in a patient with propionic acidemia.

Two abnormal metabolites, 3-keto-2-methylvaleric acid and 3-hydroxy-2-methylvaleric acid, have been identified and quantitated in the urine of a child with propionic acidemia. These metabolites may be produced as a result of the self-condensation of propionyl-CoA. Data are presented to show that the unusual ketone, 3-pentanone, which has been observed previously in the urine of patients with propionic acidemia, is produced as a result of the decarboxylation of 3-keto-2-methylvaleric acid.

Gas Chromatography-Mass Spectrometry↗
PubMed1979

Biosynthesis of prostaglandin D2, 15-ketoprostaglandin E2, and hydroxy fatty acids by ram seminal vesicle microsomes.

At high arachidonic acid concentrations (164 micrometer) and without exogenous cofactors, ram seminal vesicle microsomes produced prostaglandin E2 and two less polar products, identified as prostaglandin D2 and 15-ketoprostaglandin E2. The ratio of the biosynthetic products formed depended on the exogenous cofactor and on the arachidonic acid concentration. At high arachidonic acid concentrations (greater than 150 micrometer), tryptophan, phenol, and glutathione stimulated prostaglandin E2 formation, but each affected the formation of the other prostaglandins differently. Ascorbic acid markedly stimulated hydroxy fatty acid formation. GLC-mass spectral analysis of the hydroxy fatty acid fraction indicated the presence of 11-hydroxy-5,8,12,14-eicosatetraenoic acid, 15-hydroxy-5,8,11,13-eicosatetraenoic acid, and 12-hydroxy-5,8,10-heptadecatrienoic acid. At low arachidonic acid concentrations (30 micrometer), glutathione still stimulated prostaglandin E2 biosynthesis, but the other cofactors stimulated 6-ketoprostaglandin F1a and hydroxy fatty acid formation.

Animals↗
PubMed1992

Isolation and characterization of novel 2-hydroxy fatty acids from the phospholipids of the sponge Smenospongia aurea.

The Caribbean sponge Smenospongia aurea revealed the presence of six novel branched alpha-hydroxy fatty acids: 2-hydroxy-17-methyloctadecanoic acid, 2-hydroxy-21-methyldocosanoic acid, 2-hydroxy-22-methyltricosanoic acid, and 2-hydroxy-22-methyltetracosanoic acid, 2-hydroxy-24-methylpentacosanoic acid, and 2-hydroxy-23-methylpentacosanoic acid. These novel alpha-hydroxy fatty acids were associated with phosphatidylethanolamine. The sponges Aplysina lacunosa and Aplysina fistularis also contained considerable amounts of alpha-hydroxy fatty acids, the very long-chain 5,9,23-tricontatrienoic acid (30:3), and phytanic acid. The sterol composition of the three sponges was also studied. It indicated that A. lacunosa and A. fistularis contained large amounts of aplysterol and verongulasterol, while S. aurea did not show any of these sterols. The results are discussed in terms of the taxonomy of the species.

Aldehydes↗
PubMed1979

Iso-branched 2- and 3-hydroxy fatty acids as characteristic lipid constituents of some gliding bacteria.

The fatty acids present in the total hydrolysates of several gliding bacteria (Myxococcus fulvus, Stigmatella aurantiaca, Cytophaga johnsonae, Cytophaga sp. strain samoa and Flexibacter elegans) were analyzed by combined gas-liquid chromatography and mass spectrometry. In addition to 13-methyl-tetradecanoic acid, 15-methyl-hexadecanoic acid, hexadecanoic acid, and hexadecenoic acid, 2- and 3-hydroxy fatty acids comprised up to 50% of the total fatty acids. The majority was odd-numbered and iso-branched. Small amounts of even-numbered and unbranched fatty acids were also present. Whereas 2-hydroxy-15-methyl hexadecanoic acid was characteristic for myxobacteria, 2-hydroxy-13-methyl-tetradecanoic acid, 3-hydroxy-13-methyl-tetradecanoic acid, and 3-hydroxy-15-methyl-hexadecanoic acid were dominant in the Cytophaga-Flexibacter group.

Chemical Phenomena↗
PubMed1975

Fluorescent demonstration of basement membranes with hydroxy-naphthoic acid hydrazide.

The hydroxy-naphthoic acid hydrazide (HNAH) procedure can be employed not only for selective fluorochroming of side chain carboxyl groups of proteins, but also for demonstration of certain exoplasmic structures---particularly basement membranes. The demonstration of basement membranes by the HNAH procedure is likely related to the relatively high levels of available side chain carboxyl groups in the noncollagen glycoproteins of basement membranes.

Animals↗
PubMed1979

Direct hydroxylation in the biosynthesis of hydroxy fatty acid in lipid a of Pseudomonas ovalis.

It was found that Pseudomonas ovalis IAM 1177 had an abundance of hydroxy fatty acids such as 3-hydroxy-decanoic acid, 3-hydroxy-dodecanoic acid and 2-hydroxy-dodecanoic acid in the lipophilic part of the lipopolysaccharide fraction, which comprise 80% of total fatty acids. By using 18O2, it was shown that one oxygen atom from molecular oxygen was incorporated into 2-hydroxy-dodecanoic acid, but not into 3-hydroxy-decanoic acid. The incorporated oxygen atom was specifically located at the hydroxyl group of 2-hydroxy-dodecanoic acid. The biosynthetic pathways of these hydroxy fatty acids are discussed.

Fatty Acids↗
PubMed1976

Absolute configuration of 3-hydroxy fatty acids present in lipopolysaccharides from various bacterial groups.

The absolute configuration of 3-hydroxy fatty acids has been studied, which are present in the lipopolysaccharides of the following bacteria: Phodopseudomonas gelatinosa, Rh. viridis, Rhodospirillum tenue, Chromobacterium violaceum, Pseudomonas aeruginosa, Bordetella pertussis, Vibrio metchnikovii, Vibrio cholerae, Salmonella spp., Escherichia coli, Shigella flexneri, Proteus mirabilis, Yersinia enterocolitica and Fusobacterium nucleatum. The 3-hydroxy acids were liberated by strong alkaline hydrolysis, converted to 3-methoxy acid L-phenylethylamides and analyzed by gas-liquid chromatography. With the aid of authentic D-3-hydroxy fatty acids it was shown for all lipopolysaccharides that the 3-hydroxy acids, regardless of chain lengths, branching, 3-O-substitution or type of linkage, possess the D-configuration. 2-Hydroxydodecanoic acid, which is present in some lipopolysaccharides, was analyzed in an analogous way and shown to possess the L-configuration.

Binding Sites↗
PubMed1977

[Hydroperoxide degradation by oat isomerase. Investigation of the reaction mechanism (author's transl)].

Oat isomerase is inhibited by hydroxyoctadecadienoic acids (monohydroxy acids) to a degree comparable with inhibition by linoleic acid hydroperoxides (LHPO). Hydroxy acids seem to combine with the enzyme like LHPO do. In an experiment on LHPO breakdown by isomerase 1-14C-hydroxy acids were added and it was examined whether the epoxyhydroxy acids are formed by an intermolecular or intramolecular mechanism. In this experiment 1-14C-labeled trihydroxy acids were formed; they arise from the hydrolysis of epoxyhydroxyoctadecenoic acids formed on their part by isomerase effected LHPO-breakdown. It was determined that at least 70% of LHPO are converted by intermolecular reaction.

Edible Grain↗
PubMed1992

Quantitative determination of hydroxy fatty acids as an indicator of in vivo lipid peroxidation: oxidation products of arachidonic and docosapentaenoic acids in rat liver after exposure to carbon tetrachloride.

An improved gas chromatography-mass spectrometry method has been applied to the quantitation of both in vitro and in vivo products of lipid peroxidation in rat liver stimulated with carbon tetrachloride. The method avoids problems of autoxidation of unsaturated fatty acids during sample preparation, and the sensitivity permits assays on as little as 1 mg of tissue. This permits small samples of tissue to be obtained by biopsy from the same organ, thus making it possible to perform in vivo time studies on a single animal. Lipids from whole tissue or cell preparations are simultaneously extracted and reduced by catalytic hydrogenation and then saponified and derivatized to their pentafluorobenzyl esters and trimethylsilyl ethers. Quantitation is accomplished by negative ion chemical ionization gas chromatography-mass spectrometry, using either deuterated compounds or naturally occurring fatty acid metabolites as internal standards. Hydroxy fatty acids which result from reduction of the hydroperoxides of arachidonic and docosapentaenoic acids are found to increase within 20 min after exposure of liver or hepatocyte suspensions to carbon tetrachloride.

Animals↗
PubMed1979

Specific inhibition of the polymorphonuclear leukocyte chemotactic response to hydroxy-fatty acid metabolites of arachidonic acid by methyl ester derivatives.

The human polymorphonuclear (PMN) leukocyte chemotactic activity of the hydroxy-fatty acid metabolites of arachidonic acid, 12-l-hydroxy-5,8,10-heptadecatrienoic acid (HHT) and 12-l-hydroxy-5,8,10,14-eicosatetraenoic acid (HETE), is eliminated by methylation. Both methyl esters are specific competitive inhibitors of the PMN leukotactic responses to the parent stimuli, and exert no effect on the responses to formyl-methionyl peptides or chemotactic fragments of the fifth component of complement. 50% inhibition of the in vitro chemotactic responses of PMN leukocytes to HETE and HHT was achieved by an equimolar concentration of the corresponding methyl esters, whereas reciprocal cross-inhibition was observed at molar ratios of HETE methyl ester to HHT and HHT methyl ester to HETE which reflected the three- to fivefold greater chemotactic potency of HETE relative to HHT. Methyl esters of structurally related, but nonchemotactic, fatty acids did not competitively inhibit the chemotaxis elicited by HETE or HHT. The intraperitoneal injection of HETE in guinea pigs evoked an eosinophil response at 30 min and a neutrophil response at 5 h, which were prevented by a one-to twofold molar ratio of HETE methyl ester. The competitive inhibition of the in vitro chemotactic activity and the in vivo leukotactic effect of the unsaturated hydroxy-fatty acids by homologous methyl ester derivatives suggests that the cellular component of natural inflammatory reactions may be susceptible to specific regulation by receptor-directed modulation of the activity of the predominant chemotactic principles.

Arachidonic Acids↗