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PubMed1984

The chemical conditions on the parent body of the Murchison meteorite: some conclusions based on amino, hydroxy and dicarboxylic acids.

Amino and hydroxy acids have been identified in the Murchison meteorite. Their presence is consistent with a synthetic pathway involving aldehydes, hydrogen cyanide and ammonia in an aqueous environment (Strecker-cyanohydrin synthesis). From the various equilibrium and rate constants involved in this synthesis, four independent estimates of the ammonium ion concentrations on the parent body at the time of compound synthesis are obtained; all values are about 2 x 10(-3) M. Succinic acid and beta-alanine have also been detected in the Murchison meteorite. Their presence is consistent with a synthesis from acrylonitrile, hydrogen cyanide and ammonia. Using the equilibrium and rate constants for this synthetic pathway, and the succinic acid/beta-alanine ratio measured in the Murchison meteorite, an estimate of the hydrogen cyanide concentration of 10(-3) to 10(-2) M is obtained. Since hydrogen cyanide hydrolyzes relatively rapidly in an aqueous environment (t1/2 < 10(4) yrs) this high concentration implies a period of synthesis of organic compounds as short as 10(4) years on the Murchison meteorite parent body.

Acrylonitrile↗
PubMed2002

Predictable close-packing similarities between cis- and trans-2-hydroxy-1-cyclooctanecarboxylic acids and trans-2-hydroxy-1-cyclooctanecarboxamide.

In order to extend the experimental data already available on the close packing of cyclopentanes substituted with vicinal COX (X = OH, NH(2)) and OH groups to the analogous cyclohexanes, cycloheptanes and cyclooctanes, (1R*,2S*)-cis-2-hydroxy-1-cyclooctanecarboxylic acid (8C), (1R*,2R*)-trans-2-hydroxy-1-cyclooctanecarboxylic acid (8T) and (1R*,2R*)-trans-2-hydroxy-1-cyclooctanecarboxamide (8T*) were subjected to X-ray crystal structure analysis. In 8T and 8T*, the hydrogen bonds form infinite ribbons of dimers joined by R(2)(2)(12) rings with C(i) symmetry. Two types of dimer alternate along each ribbon. The dimers differ in the donor and acceptor roles of the functional groups. This pattern was previously deduced topologically among the possible forms of association for heterochiral dimers [Kálmán et al. (2002). Acta Cryst. B58, 494-501]. As they have the same pattern of hydrogen bonds, 8T and 8T* are isostructural. The additional donor (i.e. the second hydrogen of the NH(2) group) present in 8T* links the adjacent ribbons so as to form smaller R(2)(2)(8) rings between them. The crystals of the cis stereoisomer 8C are built up from antiparallel hydrogen-bonded helices. The topology and symmetry of this structure are the same as for the close packing of (1R*,2R*,4S*)-4-tert-butyl-2-hydroxy-1-cyclopentanecarboxamide [Kálmán et al. (2001). Acta Cryst. B57, 539-550]; only the hydrogen-bond donors and acceptors are interchanged, in the same way as in the two dimer types of 8T and 8T* ribbons. This analogy suggests that helices may originate as homochiral dimers with C(2) symmetry and polymerize into helices during crystal formation. The conformational characteristics of the heterochiral dimers observed in the title compounds and in closely related structures are discussed.

Journal Article↗
PubMed2005

Acute and subacute effects of tobacco alkaloids, tobacco-specific nitrosamines and phenethyl isothiocyanate on N'-nitrosonornicotine metabolism in rats.

N'-Nitrosonornicotine (NNN) was the first tobacco-specific nitrosamine (TSNA) identified as carcinogen in tobacco smoke, but no data exist on in vivo interactions between NNN and other tobacco alkaloids, TSNA or phenethyl isothiocyanate (PEITC) which have been demonstrated in various studies on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). Acute effects on NNN metabolism were tested in male Fischer F344 rats injected s.c. with 30nmol/kg body weight (bw) [5-(3)H]NNN either alone or simultaneously with 15mumol/kg bw nicotine, nornicotine, anatabine, or anabasine, 150mumol/kg bw cotinine, 3mumol/kg bw myosmine, or 300nmol/kg bw of either N'-nitrosoanatabine or N'-nitrosoanabasine. Another group of rats was fed a diet supplemented with PEITC at 1mumol/g diet starting 24h before NNN treatment. Within 24h more than 80% and about 10% of the radioactivity was excreted with urine and feces, respectively. Urinary metabolites were separated by reversed-phase radio-HPLC and identified by co-chromatography with UV standards. In two sets of experiments with control rats treated with NNN only, 4-hydroxy-4-(3-pyridyl)butanoic acid (hydroxy acid, 44.4/44.8%), 4-oxo-4-(3-pyridyl)butanoic acid (keto acid, 32.4/31.5%), NNN-N-oxide (5.0/3.8%), 4-(3-pyridyl)butane-1,4-diol (diol, 1.1/1.0%) and norcotinine (2.3/1.0%) were consistently detected besides unmetabolised NNN (4.7/3.3%). Co-treatment with nicotine, cotinine, nornicotine and PEITC shifted the contribution of the two major metabolites significantly in favor of hydroxy acid (108-113% of control) as compared to keto acid (86-90% of control). The same treatments also increased norcotinine (135-170% of control). These changes are consistent with a decreased metabolic activation of NNN. In subacute studies rats received NNN in drinking water for 4 weeks at a daily dose of 30 nmol/kg bw with or without nornicotine at 15 micromol/kg bw or myosmine at 3 micromol/kg bw. On the last day of the experiment all rats received [5-(3)H]NNN at 30 nmol/kg bw with a contaminated apple bite followed by collection of urine and feces for 18h. Most of the radioactivity, 87-96% of the dose, was recovered in urine and only minor amounts have been excreted in feces or persisted in blood. In urine of the NNN-control group keto acid (32.2%) and unmetabolised NNN (3.9%) were present in identical amounts as in the acute experiment whereas hydroxy acid (41.4% of total radioactivity in urine, 93% of acute NNN control) was reduced in expense of the minor NNN metabolites. Co-administration of nornicotine resulted in a small but significant rise of keto acid (107% of control) and a significant decrease in NNN-N-oxide (76% of control). After co-treatment with myosmine the increase of keto acid (104% of control) was even less but still significant whereas NNN-N-oxide and diol were significantly reduced to 72% and 79% of control, respectively. Our experiments with rats indicate significant mutual effects of some of the major tobacco alkaloids and most relevant TSNA. Further studies on the impact on smokers and the inhibitory effects of isothiocyanates are needed for a final risk assessment.

Alkaloids↗
PubMed2002

The omega-hydroxy palmitic acid induced apoptosis in human lung carcinoma cell lines H596 and A549.

We have found that omega-hydroxy palmitic acid (16-hydroxy palmitic acid, omega-HPA) has both cell growth inhibiting and cell death inducing actions on human lung adenosquamous carcinoma cell line H596 and adenocarcinoma cell line A549. Further, these effects were dose- and time-dependent in both cell lines. However, in squamous carcinoma cell line H226, omega-HPA had no cytotoxic effect. On the other hand, in the human small cell lung carcinoma (SCLC) cell line H128, this compound showed weak cytotoxicity. The sensitivity toward omega-HPA was higher in H596 cells than in A549 cells. In both H596 and A549 cells, cell growth was inhibited to 24.4 and 9.4%, respectively, by treatment with 100 microM omega-HPA for 12 h. In the 24 h treatment cells, growth inhibition was increased to 100 and 38.1%, respectively. In cytotoxicity experiments, the number of dead cells increased with incubation times in the presence of omega-HPA: on three days incubation with 100 microM omega-HPA, viability was 0 and 13.5%, respectively, in H596 and A549 cells. Further, the fragmentation of DNA to oligonucleosomal-sized ladder fragments, which is an index of apoptosis, was observed in both cell lines on treatment with omega-HPA. Therefore, it is assumed that these cell deaths induced by omega-HPA, were apoptosis in these cell lines. Since the number of dead cells following treatment with omega-HPA decreased by treatment with omega-HPA in combination with Z-VAD-fmk, a caspase family inhibitor, it is thought that apoptotic cell death was related to caspase activity.

Adenocarcinoma↗
PubMed1982

Norepinephrine metabolism in man using deuterium labeling: turnover 4-hydroxy-3-methoxymandelic acid.

4-Hydroxy-3-methoxymandelic acid (HMMA; VMA) labeled with three deuterium atoms was used to study the turnover and fate of HMMA following intravenous injection. Five healthy men were given a pulse dose of 5.0 mumol of labeled HMMA. Plasma and urinary levels of both endogenous and labeled HMMA were subsequently followed by gas chromatography-mass spectrometry using selected ion detection. The kinetic parameters were determined both with and without compensation for the pool expansion caused by the injection of labeled HMMA. The urinary recovery of labeled HMMA was 85 +/- 10% (mean +/- SD). No conversion of HMMA to 4-hydroxy-3-methoxyphenyl glycol (HMPG) occurred. The biological half-life of HMMA was 0.54 +/- 0.22 h. The apparent volume of distribution was 0.36 +/- 0.11 L/kg. The production rate or body turnover was 1.27 +/- 0.51 mumol HMMA/h and urinary excretion rate was 0.82 +/- 0.22 mumol/h. These results show that HMMA is turnover over rapidly in a relatively small volume of distribution and that, unlike HMPG, it is an end metabolite of norepinephrine in man.

Adult↗
PubMed2001

Highly diastereoselective Michael addition reactions of butane-2,3-diacetal desymmetrized glycolic acid. Preparation of alpha-hydroxy-gamma-amino acid derivatives.

[reaction--see text] The butane-2,3-diacetal (BDA) desymmetrized glycolic acid building block undergoes efficient and highly diastereoselective lithium enolate Michael additions to alpha,beta-unsaturated ketones, lactones, and nitro olefins. Subsequent deprotection of these Michael adducts gives alpha-hydroxy acids in very high yield. Hydrogenation of the nitro group in some of the adducts leads to gamma-lactams, which can be easily converted into alpha-hydroxy-gamma-amino acid derivatives.

Acetals↗
PubMed1981

Norepinephrine metabolism in man using deuterium labelling: the conversion of 4-hydroxy-3-methoxyphenylglycol to 4-hydroxy-3-methoxymandelic acid.

4-Hydroxy-3-methoxyphenylglycol (HMPG) labelled with three deuterium atoms was used to study the disposition of peripherally administered HMPG. Five healthy men were given an intravenous pulse dose of 4.3 mumol of labelled HMPG and subsequent plasma and urine levels of endogenous and labelled HMPG as well as those of 4-hydroxy-3-methoxymandelic acid (HMMA, VMA) were determined by gas chromatography-mass spectrometry, using selected ion detection. Approximately 40% of the injected amount of deuterium-labelled HMPG was recovered in the urine as HMMA and another 40% was eliminated as HMPG conjugates. Thus, the HMPG formed from norepinephrine either in the central or peripheral nervous system undergoes both conjugation and extensive oxidation.

Adult↗
PubMedDate not supplied

Stereospecific synthesis of (R)-2-hydroxy carboxylic acids using recombinant E. coli BL21 overexpressing YiaE from Escherichia coli K12 and glucose dehydrogenase from Bacillus subtilis.

The yiaE gene from Escherichia coli K12 was functionally expressed in E. coli BL21 using an IPTG inducible pET expression system (2.1 U/mg), and YiaE was purified to a specific activity of 18 U/mg. The purified enzyme catalyzes reduction of various aromatic and aliphatic 2-oxo carboxylic acids to the corresponding (R)-2-hydoxy carboxylic acids using NADPH. For practical applications, the problem of NADPH recycle was effectively solved by using recombinant E. coli overexpressing YiaE and glucose dehydrogenase from Bacillus subtilis in the same cell. The recombinant E. coli was used to prepare (R)-phenyllactic acid and (R)-2-hydroxy-4-phenylbutanoic acid from the corresponding 2-oxo carboxylic acids (98% ee) while the alpha-carbonyl group of 2,4-dioxo-4-phenylbutyric acid was reduced regio- and stereospecifically to give (R)-2-hydroxy-4-oxo-4-phenylbutyric acid (97% ee) in quantitative yields. The cells could be recycled for 3 days at room temperature in 100 mM phosphate buffer (pH 7.0) without loss of activity, which reduced to 70% after 1 week.

Bacillus subtilis↗
PubMed1987

Diesters of 3-hydroxy fatty acids produced by the uropygial glands of female mallards uniquely during the mating season.

The uropygial gland secretions produced by female mallards (Anas platyrhynchos) throughout the year were analyzed by thin-layer chromatography and combined gas-liquid chromatography and mass spectrometry. Most of the year, the secretion was composed of wax esters. With the beginning of the mating season in the middle of March, a polar component appeared which became the dominant and sole component of the secretion through April and May and as the mating season ended in June, wax esters became the sole component of the secretion. The polar components were identified to be diesters of n-C8, n-C10, and n-C12 3-hydroxy acids with n-C16 and n-C18 alcohols and n-C6 to C16 even chain acids. Immediately after the diester-producing period the female uropygial glands produced very long chain wax esters composed of fatty acids longer than C12. By the end of August, shorter chain wax esters composed of C6 and C12 acids became the dominant components of the secretion and this composition, previously considered characteristic of mallards, remained constant until March. The observed disappearance of the short chain waxes during the postnuptial period is similar to that in males. The dramatic changes in the composition of the uropygial glands similar to those observed in the female mallards during the mating season have not yet been observed in any other species.

Alcohols↗
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↗
PubMed1986

Increased aggregation and arachidonic acid transformation by psoriatic platelets: evidence that platelet-derived 12-hydroxy-eicosatetraenoic acid increases keratinocyte DNA synthesis in vitro.

Certain arachidonic metabolites may play a pathogenic role in psoriasis. Platelets are rich sources of 12-hydroxy-eicosatetraenoic acid (12-HETE) and thromboxane A2, mediators of skin inflammation and platelet aggregation, respectively. We have studied untreated psoriatic patients without a history of diabetes mellitus and smoking. In psoriatics, platelet aggregation elicited by thrombin, ADP, and ristocetin was significantly enhanced as compared with healthy adult volunteers. Enhancement of platelet aggregation was detected in patients with both minimal and widespread disease. The formation of 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT), a cyclooxygenase product, and 12-HETE, a 12-lipoxygenase product, was increased in psoriatics with widespread disease but not in those with minimal disease. Formation of 12-HETE was stimulated to a higher degree (125%) than HHT (98%) in psoriasis (P less than 0.05). Addition of platelet-derived 12-HETE to cultured human epidermal keratinocytes resulted in a stimulation of the DNA synthesis (68% at 10(-7) M). These data suggest that platelet activation occurs in psoriasis, and that release of inflammatory and mitogenic compounds by activated platelets may play a role in the pathophysiology of psoriasis. Whether enhanced platelet aggregation in psoriasis is associated with occlusive vascular disease needs further investigation.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1963

PREPARATION OF OPTICALLY ACTIVE GAMMA- AND DELTA-LACTONES BY MICROBIOLOGICAL REDUCTION OF THE CORRESPONDING KETO ACIDS.

It was found, by means of simple screening methods, that several yeasts (Saccharomyces and Candida), molds (Cladosporium), and bacteria (Sarcina) are able to reduce keto acids to hydroxy acids, which are easily converted into lactones. Chemical analysis showed that some of the microorganisms (Saccharomyces and Candida) produce dextrorotatory lactones and others (Cladosporium and Sarcina) produce levorotatory lactones. High yields of dextrorotatory (both gamma- and delta-lactones) were obtained by using Saccharomyces cerevisiae. The physical properties of the carefully distilled lactones obtained indicated high purity and high optical purity.

Bacteria↗
PubMed1983

Episodic hypoglycemia with psi-hydroxy fatty acid excretion.

We present case histories of two young children with episodes of hypoglycemia, elevation of SGOT, low insulin levels, increased urinary excretion of psi-hydroxy fatty acids (5-hydroxyhexanoic, 7-hydroxyoctanoic and 9-hydroxydecanoic), traces of the corresponding psi-ketoacids and elevations of urinary adipic, suberic, and sebacic acids. The ratio of psi-hydroxy fatty acids to 3-hydroxybutyric in the urine of these patients is higher than in patients of similar ages with similar illnesses. These acids persisted while the patients were well. Increased urinary psi-hydroxy fatty acids could be reproduced by a load of medium chain triglycerides without precipitating other clinical symptoms. Three children with hypoglycemia were found not to excrete measurable amounts of these unusual acids while ill. A medium chain triglyceride load in one of these children after recovery failed to elicit psi-hydroxy acid excretion. Small amounts of urinary 5-hydroxyhexanoic acid only were found in two patients with acute Reye's syndrome and in three of five severely ill children with starvation ketonuria. In this last group, no urinary psi-hydroxyacids could be detected after recovery. Normal children do not excrete measurable amounts (less than 1 mg/g creatinine) of these psi-hydroxyacids.

Aspartate Aminotransferases↗
PubMed2005

Biosynthesis of medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) by Comamonas testosteroni during cultivation on vegetable oils.

Comamonas testosteroni has been studied for its ability to synthesize and accumulate medium chain length poly(3-hydroxyalkanoates) (mcl-PHAs) during cultivation on vegetable oils available in the local market. Castor seed oil, coconut oil, mustard oil, cotton seed oil, groundnut oil, olive oil and sesame oil were supplemented in the mineral medium as a sole source of carbon for growth and PHAs accumulation. The composition of PHAs was analysed by a coupled gas chromatography/mass spectroscopy (GC/MS). PHAs contained C6 to C14 3-hydroxy acids, with a strong presence of 3-hydroxyoctanoate when coconut oil, mustard oil, cotton seed oil and groundnut oil were supplied. 3-hydroxydecanoate was incorporated at higher concentrations when castor seed oil, olive oil and sesame oil were the substrates. Purified PHAs samples were characterized by Fourier Transform Infrared (FTIR) and 13C NMR analysis. During cultivation on various vegetable oils, C. testosteroni accumulated PHAs up to 78.5-87.5% of the cellular dry material (CDM). The efficiency of the culture to convert oil to PHAs ranged from 53.1% to 58.3% for different vegetable oils. Further more, the composition of the PHAs formed was not found to be substrate dependent as PHAs obtained from C. testosteroni during growth on variety of vegetable oils showed similar compositions; 3-hydroxyoctanoic acid and/or 3-hydroxydecanoic acid being always predominant. The polymerizing system of C. testosteroni showed higher preference for C8 and C10 monomers as longer and smaller monomers were incorporated less efficiently.

Comamonas testosteroni↗
PubMedDate not supplied

[Comparative research on the cerebroside and sulfocerebroside content of the mammalian brain].

Data are presented on cerebroside and sulfocerebroside content of the brain for 31 mammalian species from 8 orders. The increase in concentration of both glycolipids in the brain of mammals in phylogenesis was demonstrated. Low levels of cerebrosides and sulfocerebrosides were found in the brain of lower mammals (Insectivora, Chiroptera) and high ones--in the brain of higher mammals (Carnivora, Primates). Irrespectively from taxonomic position and ecological factors, in the brain of all mammals investigated higher content of cerebrosides with hydroxy acids was found as compared to the content of cerebrosides with normal fatty acids. The ratio of these cerebrosides in the brain of terrestrial mammals is 2-3 times higher than in aquatic and semi-aquatic ones. The data obtained are discussed in relation to the development of the brain of mammals during their phylogenesis.

Animals↗
PubMedDate not supplied

[Cerebrosides and sulfocerebrosides in the brain of insectivorous mammals].

Brain cerebrosides (C) and sulfocerebrosides (S) of Insectivora, which represent the most ancient and primitive order of placentary mammals, were first studied. The content of C and S is higher in hedgehogs (Erinaceus europaeus, E. auritus) and mole (Talpa europaea) brains as compared to shrew (Sorex araneus) brain. Hydroxy fatty acids predominate over normal fatty acids in C of all studied insectivora brains. The fatty acid content of C and S of the Insectivora brains is similar in being rich in palmitic, stearic and behenic normal acids and hydroxybehenic and hydroxylignocerinic acids. Hydroxy fatty acids of C and S are more saturated and they have a longer chain (sum C24-26 acids) than the normal acids. C and S of insectivora and primate brains are compared. The data may be of importance for the understanding of the biochemical evolution of the nervous system of mammals.

Animals↗