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PubMed2004

Characterization of the antifungal activity on Botrytis cinerea of the natural diterpenoids kaurenoic acid and 3beta-hydroxy-kaurenoic acid.

The antifungal activity on Botrytis cinerea of the diterpenoids 3beta-hydroxy-kaurenoic acid and kaurenoic acid, obtained from the resinous exudates of Pseudognaphalium vira vira, was determined. 3beta-Hydroxy-kaurenoic acid reduced the mycelial growth of B. cinerea in solid and liquid media. Additionally, the damage produced by the fungus on the surface of tomato leaves in the presence of the diterpenoids was evaluated. A higher protective effect was observed in the presence of the hydroxylated diterpene. On the other hand, the effect of the diterpenoids on the production of enzymes that participate in the plant infection by B. cinerea was analyzed. p-Nitrophenylbutyrate esterase production was induced by both diterpenoids, whereas laccase production was only induced by the hydroxylated diterpene. In the study of the mechanism of action of these compounds, it was determined that 3beta-hydroxy-kaurenoic acid would produce permeabilization of the cell membrane of B. cinerea.

Botrytis↗
PubMed1983

Partial synthesis and physical properties of cerebroside sulfate containing palmitic acid or alpha-hydroxy palmitic acid.

Chromatographically pure galactosylceramide I3-sulfate (cerebroside sulfate (CBS)) containing palmitic acid or D-2-hydroxypalmitic acid has been prepared by the acylation of galactosylsphingosine I3-sulfate obtained from the saponification of bovine brain sulfatides. Optically pure D-2-hydroxypalmitic acid was obtained by adapting literature methods for the synthesis of the racemic acid and its resolution. The thermotropic behavior of the two synthetic CBSs were compared to each other and to the corresponding components in natural CBS, obtained by fractionation of bovine brain sulfatides, in order to determine the contribution of the hydroxy fatty acid to intermolecular hydrogen bonding between molecules of the lipid. The gel to liquid crystalline phase transition temperature (Tc) of the hydroxy fatty acid (HFA) synthetic form is 53.2 degrees C, 3 degrees higher than that of the non-hydroxy fatty acid (NFA) form at low concentrations of Na+ or K+. A similar difference was found for the HFA and NFA forms of natural CBS. The enthalpy of the NFA synthetic form is 8.5 kcal/mol, about 30% greater than that of the HFA form. The difference in Tc between the NFA and HFA forms is abolished as the Na+ or K+ concentration increases but the difference in enthalpy persists. Increasing cation concentration, over the range 0.01-2 M, increases Tc more than for an acidic phospholipid, phosphatidylglycerol, probably due to increased intermolecular hydrogen bonding as the charged sulfate is shielded. K+ causes a 3-4 degrees C greater increase in Tc relative to that produced by Na+ while K+ and Na+ have similar effects on phosphatidylglycerol.

Animals↗
PubMed1983

Inhibition of renin by angiotensinogen peptide fragments containing the hydroxy amino acid residue 5-amino-3-hydroxy-7-methyloctanoic acid.

The 3R,5S and 3S,5S diastereoisomers of the hydroxy amino acid 5-amino-3-hydroxy-7-methyloctanoic acid (AHMOA) were synthesized from L-leucine and then incorporated into various peptide fragments of angiotensinogen to give the following polypeptides: AHMOA-Val-Phe-OCH3, His-AHMOA-Val-Phe-OCH3, and AHMOA-Ile-His-OCH3. These compounds were tested in an in vitro renin assay system for their ability to inhibit either hog kidney renin or human amniotic renin. The most active analogue of the series was (3R,5S)-AHMOA-Val-Phe-OCH3 (16). Against hog kidney renin, this compound possessed a Ki = 1.7 X 10(-4) M, while against human amniotic fluid, 16 had a Ki = 0.95 X 10(-4) M. The analogues AHMOA-Val-Phe-OCH3 and His-AHMOA-Val-Phe-OCH3 exhibited noncompetitive kinetics when the 3R,5S isomer of AHMOA was employed and competitive kinetics when the 3S,5S diastereoisomer of AHMOA was used.

Amino Acid Sequence↗
PubMed2000

A novel sphingoglycolipid containing galacturonic acid and 2-hydroxy fatty acid in cellular lipids of Sphingomonas yanoikuyae.

A novel sphingoglycolipid was isolated from Sphingomonas yanoikuyae, and its structure was identified as a galacturonosyl-beta (1-->1)-ceramide. This was a characteristic sphingoglycolipid present in S. yanoikuyae and certain other species of Sphingomonas, such as Sphingomonas mali, Sphingomonas terrae, and Sphingomonas macrogoltabidus, but not in the type species of Sphingomonas, Sphingomonas paucimobilis.

Carbohydrates↗
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↗
PubMed2000

Simultaneous micellar electrokinetic chromatographic determination of isomeric fatty acid hydroperoxides and corresponding hydroxy fatty acids.

The high selectivity and efficiency of micellar electrokinetic chromatography with a borax-sodium dodecylsulfate (SDS) or meglumin-SDS buffer make possible the rapid separation of hydroperoxy and hydroxy fatty acids and the non-oxidised unsaturated fatty acids from which they are derived. Nearly all the isomers of the hydroperoxides and hydroxy fatty acids derived from oleic, linoleic, alpha- and gamma-linolenic and arachidonic acids can be determined both qualitatively and quantitatively within ca. 10 min. The system has as many as 1 x 10(6) theoretical plates, and the detection limits with UV diode array detection at 195 or 234 nm are in the micromolar range.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed1990

Modulation of guinea pig airway reactivity by the linoleic acid metabolite 13-hydroxy-octadecadienoic acid (13-HODE).

The influence of the linoleic acid metabolite 13-hydroxy-octadecadienoic acid (13-HODE) on guinea pig tracheal reactivity to both contractile and relaxant agonists was investigated in vitro. 13-HODE induced an increased contraction of tracheal rings to histamine, whereas methacholine responsiveness was not significantly affected. Relaxant responses to isoprenaline and prostaglandin E2 were not influenced either.

Animals↗
PubMed1990

Preparation and purification of soybean lipoxygenase-derived unsaturated hydroperoxy and hydroxy fatty acids and determination of molar absorptivities of hydroxy fatty acids.

A method was developed for the preparation and purification of polyunsaturated hydroperoxy and hydroxy fatty acids from 18:2n-6, 18:3n-6, 18:3n-3, 20:3n-6, 20:3n-3, and 20:4n-6 with soybean lipoxygenase. This method involved incubation of unsaturated fatty acids in Tris-HCl buffer with soybean lipoxygenase and extraction of reaction products on C18 solid-phase columns. The yields of conversion of fatty acid substrate to oxygenated products were in all cases greater than or equal to 95%. C18 solid-phase extracted reaction products were purified by C18 HPLC, yielding 3-4 mg of products with purities of greater than or equal to 98%. Purified polyunsaturated hydroxy fatty acids were characterized by HPLC and mass spectral analysis and showed absorption spectra with maximum absorption occurring between 234.5 and 237.5 nm due to the presence of a conjugated diene function. Polyunsaturated hydroxy fatty acid potassium salts were converted to (4-bromobenzoyl)methyl esters by reaction with 2,4'-dibromoacetophenone in the presence of 18-crown-6. Molar absorptivities for the conjugated diene functions were determined by relating their absorbance to the absorbance contributed by the 4-bromobenzoyl chromophore and its molar absorption intensity of 17.6 X 10(3) (M.cm)-1. The molar absorptivities determined for 13-OH-9,11-18:2, 13-OH-6,9,11-18:3, 13-OH-9,11,15-18:3, 15-OH-11,13-20:2, 15-OH-8,11,13-20:3, 15-OH-11,13,17-20:3, and 15-OH-5,8,11,13-20:4 ranged from 23.2 x 10(3) to 24.6 x 10(3) (M.cm)-1. The molar absorbtivity values of 18.8 x 10(3) and 20.3 x 10(3) (M.cm)-1 determined for commercial, chemically synthesized 12-OH-5,8,10,14-20:4 [12-(S)-hydroxyeicosa-5,8,10,14-tetraenoic acid (12(S)-HETE)] and 5-OH-6,8,11,14-20:4 ((+/-)-5-HETE) were lower than that of soybean lipoxygenase-derived 15-OH-5,8,11,13-20:4 (15-HETE), which exhibited a molar absorptivity of 23.3 x 10(3) (M.cm)-1. The molar absorptivity values determined for 5-, 12-, and 15-HETE are considerably lower than 30.5 x 10(3) (M.cm)-1, which was reported previously.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMedDate not supplied

Fecal excretions of hydroxy fatty acid and bile acid in diabetic diarrheal patients.

Thirteen normal subjects, 5 diarrheal controls (Group I) and 13 diabetics without peripheral neuropathy (Group II) were compared with 7 diabetic patients (Group III) with respect to fecal excretions of bile acids and hydroxy fatty acids for pathogenesis of diabetic diarrhea. The mean fecal excretions of bile acids per day were 304.9 mg for the normal controls, 297.8 mg for Group I, and 382.4 mg for Group II, while those of Group III were significantly higher (958.2 mg, p < 0.01) than the foregoing groups, and nearly three times as much as the controls. As to the fecal fatty acid excretion, there were no significant differences observed among these groups. The percentages of fecal hydroxy fatty acids were not significantly different in normal subjects (1.5%), Group I (2.0%), and Group II (1.2%). In contrast, the percentage of hydroxy fatty acid for Group III was greatly (p < 0.01) increased (13.2%). From the above results, the percentage of hydroxy fatty acid in diabetic diarrheal patients was high, suggesting that there is bacterial overgrowth. Meanwhile, the fecal bile acid level was increased about three times, indicative of poor absorption of bile acid from mild to moderate degree. Therefore, it is considered improbable that fecal hydroxy fatty acids and bile acids are the cause of diabetic diarrhea.

Adult↗
PubMed1997

New alcohol dehydrogenases for the synthesis of chiral compounds.

The enantioselective reduction of carbonyl groups is of interest for the production of various chiral compounds such as hydroxy acids, amino acids, hydroxy esters, or alcohols. Such products have high economic value and are most interesting as additives for food and feed or as building blocks for organic synthesis. Enzymatic reactions or biotransformations with whole cells (growing or resting) for this purpose are described. Although conversions with whole cells are advantageous with respect to saving expensive isolation of the desired enzymes, the products often lack high enantiomeric excess and the process results in low time-space-yield. For the synthesis of chiral alcohols, only lab-scale syntheses with commercially available alcohol dehydrogenases have been described yet. However, most of these enzymes are of limited use for technical applications because they lack substrate specificity, stability (yeast ADH) or enantioselectivity (Thermoanaerobium brockii ADH). Furthermore, all enzymes so far described are forming (S)-alcohols. Quite recently, we found and characterized several new bacterial alcohol dehydrogenases, which are suited for the preparation of chiral alcohols as well as for hydroxy esters in technical scale. Remarkably, of all these novel ADHs the (R)-specific enzymes were found in strains of the genus Lactobacillus. Meanwhile, these new enzymes were characterized extensively. Protein data (amino acid sequence, bound cations) confirm that these catalysts are novel enzymes. (R)-specific as well as (S)-specific ADHs accept a broad variety of ketones and ketoesters as substrates. The applicability of alcohol dehydrogenases for chiral syntheses as an example for the technical use of coenzyme-dependent enzymes is demonstrated and discussed in this contribution. In particular NAD-dependent enzymes coupled with the coenzyme regeneration by formate dehydrogenase proved to be economically feasible for the production of fine chemicals.

Alcohol Dehydrogenase↗
PubMedDate not supplied

A novel electrophilic reagent, 4-(N-chloroformylmethyl-N-methyl)amino- 7-N,N-dimethylaminosulphonyl-2,1,3-benzoxadiazole (DBD-COCl) for fluorometric detection of alcohols, phenols, amines and thiols.

A novel electrophilic reagent for alcohols, phenols, amines and thiols, 4-(N-chloroformylmethyl-N-methyl)amino-7-N,N-dimethylaminosulph onyl-2,1,3- benzoxadiazole (DBD-COCl) was synthesized. The reactivity of the reagent to these nucleophiles was studied using high-performance liquid chromatography (HPLC) with precolumn derivatization techniques. DBD-COCl reacted in benzene solution at the room temperature or 60 degrees C with androsterone (a representative of hydroxyls), (-)-mandelic and D,L-lactic acid (hydroxy acid), estrone (phenol), benzylamine (primary amine), phenetidine (aromatic amine) and alpha-mercapto-N,2-naphthylacetamide (thiol) to give fluorescent products bearing fluorescence wavelengths at between 543 nm and 555 nm (excitation at between 437 nm and 445 nm). The base catalyst, quinuclidine was required to complete the reaction with the nucleophiles except aromatic amines. The reaction solution was subjected to a reversed phase HPLC and the detection limits of the derivatives were at the femto mol range on column.

Alcohols↗
PubMed1996

Enantiomer separation by gas and high-performance liquid chromatography with tripeptide derivatives as chiral stationary phases.

Excellent enantiomer separation of a variety of racemic compounds, including alcohols, amines, amino alcohols, carboxylic acids, hydroxy acids and amino acids, was achieved by GC and HPLC with tripeptide derivatives, containing L-valyl-L-valyl-L-valine isopropyl ester as a chiral selector, bonded to amino silicone oil (CSP-3) and N-(2-aminoethyl)-3-aminopropyl silica gel (CSP-4) via a triazine ring, respectively. These results show that the hydrogen bonding association between solutes and chiral stationary phases (CSPs) can play an important role in chiral recognition in both GC and HPLC. The joint use of two CSPs is promising for the direct separation of racemic compounds.

Amino Acid Sequence↗