Identification of the Carotenoid Pigment Canthaxanthin from Photosynthetic Bradyrhizobium Strains

Canthaxanthin (4,4(prm1)-diketo-(beta)-carotene) is produced as the major carotenoid pigment by orange- and dark-pink-pigmented bacteriochlorophyll-containing Bradyrhizobium strains isolated from stem nodules of Aeschynomene species. These two new pigmentation groups differ from the well-studied strain BTAi1, which accumulates spirilloxanthin as the sole carotenoid.     

Metabolism of leukotriene E4 to 5-hydroxy-6-mercapto7,9-trans-11,14-cis-eicosatetraenoic acid by microfloral cysteine-conjugate beta-lyase and rat cecum contents

Leukotriene E4 was incubated with cysteine-conjugate beta-lyase isolated from the intestinal bacterium Eubacterium limosum. The reaction was terminated by addition of iodoacetic acid or dimethyl sulfate, and the products formed were isolated by reverse-phase high-performance liquid chromatography. The structures of two adducts of a metabolite were determined by uv spectroscopy, by gas-liquid radiochromatography, and by comparisons with chemically synthesized reference compounds. They were 5-hydroxy-6-S-carboxymethylthio-7,9-trans-11,14-cis-eicosatetraeno ic acid (iodoacetic acid adduct) and 5-hydroxy-6-S-methylthio-7,9-trans-11,14-cis-eicosatetraenoic acid (dimethyl sulfate adduct) indicating that the structure of the underivatized metabolite was 5-hydroxy-6-mercapto-7,9,11,14-eicosatetraenoic acid (5,6-HMETE). The latter product is formed by beta-lyase-catalyzed cleavage of the cysteine C-S bond in leukotriene E4. Leukotriene E4 was also metabolized to 5,6-HMETE by rat cecal contents. A product formed was trapped as the iodoacetic acid derivative and identified as 5-hydroxy-6-S-carboxy-methylthio-7,9,11,14-eicosatetraenoic acid. It is concluded that intestinal leukotriene E4, originating from biliary excretion of systemic cysteinyl leukotrienes or produced in the intestine, is converted by microfloral cysteine-conjugate beta-lyase to 5,6-HMETE.     

山石榴果实挥发油的化学成分分析

采用超临界CO2提取山石榴果实挥发油,并利用GC-MS联用技术分析挥发油的化学组成。从山石榴果实挥发油中分离、鉴定出33个化合物,占挥发油总量的89.43%。挥发油主要由各种酯、脂肪酸成分组成,含量较高的成分是11,14-二十碳二烯酸甲酯(11,14-eicosadienoic acid,methyl ester,42.49%),棕榈酸(pal mitic acid,15.34%),硬脂酸(stearic acid,10.54%),肉豆蔻酸(myristic acid,6.26%),十六酸乙酯(hexa-decanoic acid,ethyl ester,5.84%)。     

A rearranged abietane diterpenoid from the root of Salvia aethiopis

From the root of Salvia aethiopis a new diterpenoid, salvipisone, has been isolated. Its structure, 12-hydroxy-4,5-seco-5,10-friedo-4(18),5(10),6,8,12-abietapentaen-11,14-dione, was established by spectroscopic means and by partial synthesis from aethiopinone. The previously known diterpenoids aethiopinone and royleanone were also found in the same source.     

Cytotoxic abietane diterpenes from Hyptis martiusii Benth

From roots of Hyptis martiusii Benth. two tanshinone diterpenes were isolated, the new 7beta-hydroxy-11,14-dioxoabieta-8,12-diene (1) in addition to the known 7alpha-acetoxy-12-hydroxy-11,14-dioxoabieta-8,12-diene (7alpha-acetoxyroyleanone) (2). Structures of 1 and 2 were established by spectroscopic means. The cytotoxic activity against five cancer cell lines was evaluated. Compounds 1 and 2 displayed considerable cytotoxic activity against several cancer cell lines with IC50 values in the range of 3.1 to 11.5 microg/ml and 0.9 to 7.6 microg/ml, respectively. The cytotoxic activity seemed to be related to inhibition of DNA synthesis, as revealed by the reduction of 5-bromo-2'-deoxyuridine incorporation and induction of apoptosis, as indicated by the acridine orange/ethidium bromide assay and morphological changes after 24 h of incubation in leukemic cells.     

Microbiological transformations of nabilone, a synthetic cannabinoid.

A screening program was conducted to find microorganisms that modify the synthetic cannabinoid nabilone. After purification, the products from three cultures were analyzed by spectral methods to determine their chemical structures. An optically active 9S-hydroxy-6aR,10aR-trans cannabinoid was isolated from a culture of an unidentified soil bacterium designated A24007. From Bacillus cereus cultures were isolated a 9S,6'-dihydroxy-6aR,10aR-trans cannabinoid, a 9S-hydroxy-6'-keto-6aR,10aR-trans cannabinoid, a 9-keto-6'-hydroxy-6aS,10aS-trans cannabinoid, and a 6',9-diketo-6aS,10aS-trans cannabinoid. All of these products were optically active, as was a 9S-hydroxy-6aS,10AS-trans cannabinoid also isolated from B. cereus cultures. A series of acidic products were isolated from cultures of Nocardia salmonicolor. All of these products contained a carboxylic acid group at the terminal end of three-position alkyl side chains having varying numbers of carbon atoms. Two of the acidic products contained a 9-keto group, whereas all other carboxylic acid products were 9-hydroxy cannabinoids. The array of products obtained from incubation of nabilone indicates the usefulness of microbial transformations in the preparation of new cannabinoids.     

Abietane diterpenoids from Clerodendrum mandarinorum

From the stem of Clerodendrum mandarinorum Diels (Verbenaceae), three new abietane derivatives, mandarones A, B and C, have been isolated. The structures were characterized as (5R,10S)-12-hydroxy-8,11,13-abietatriene-37-dione (mandarone A), (16 S)-12,16-epoxy-11,14-dihydroxy-17(15→16)-abeo-abieta-5,8,11,13-tetraene-7-one (mandarone B) and 12,16-epoxy-11,14-dihydroxy-17(15→16)-abeo-abieta-2,5,8,11,13,15-hexaene-7-one (mandarone C) on the basis of spectral analysis. Mandarones B and C possess a rearranged abietane skeleton which contains a 17(15→16)-abeo-abietane framework.     

Metabolism of leukotriene E4 by rat tissues: formation of N-acetyl leukotriene E4

Leukotriene E4 was incubated with subcellular fractions from rat liver homogenates. A product identified as 5-hydroxy-6-S-(2-acetamido-3-thiopropionyl)-7,9-trans-11,14- cis-eicosatetraenoic acid (N-acetyl leukotriene E4) was formed. Enzymes catalyzing the reaction were associated with particulate fractions sedimenting between 600 and 8500 g and 20,000 and 105,000 g. Acetyl coenzyme A served as the donor of the acetyl group. N-Acetyl leukotriene E4 was also formed by the 105,000g sediment fractions from kidney, spleen, skin, and lung. The myotropic activity of N-acetyl leukotriene E4 on isolated guinea pig ileum was reduced over 100-fold compared to that of leukotriene D4.     

Isolation of Erwinia chrysanthemi kduD mutants altered in pectin degradation.

Mutants of Erwinia chrysanthemi impaired in pectin degradation were isolated by chemical and Mu d(Ap lac) insertion mutagenesis. A mutation in the kduD gene coding for 2-keto-3-deoxygluconate oxidoreductase prevented the growth of the bacteria on polygalacturonate as the sole carbon source. Analysis of the kduD::Mu d(Ap lac) insertions indicated that kduD is either an isolated gene or the last gene of a polycistronic operon. Some of the Mu d(Ap lac) insertions were kduD-lac fusions in which beta-galactosidase synthesis reflected kduD gene expression. In all these fusions, beta-galactosidase activity was shown to be sensitive to catabolite repression by glucose and to be inducible by polygalacturonate, galacturonate, and other intermediates of polygalacturonate catabolism. Galacturonate-mediated induction was prevented by a mutation which blocked its metabolism to 2-keto-3-deoxygluconate. 2-Keto-3-deoxygluconate appeared to be the true inducer of kduD expression resulting from galacturonate degradation. 5-Keto-4-deoxyuronate or 2,5-diketo-3-deoxygluconate were the true inducers, originating from polygalacturonate cleavage. These three intermediates also appeared to induce pectate lyases, oligogalacturonate lyase, and 5-keto-4-deoxyuronate isomerase synthesis.     

Rearranged abietane diterpenoids from the root of Teucrium lanigerum

A new rearranged abietane diterpenoid, teuvincenone J, was isolated from the root of Teucrium lanigerum Lag. (Labiatae) together with four known compounds, teuvincenones A–D. The structure of the new diterpene [12,16-epoxy-11,14-dihydroxy-17(15 → 16)-abeo-3α,18-cyclo-8,11,13,15-abietatetraen-7-one] was established by 1D- and 2D-NMR spectroscopic means. These diterpenes could be significant from a chemotaxonomic point of view.     

Novel acyclic diterpenes from the brown alga Cystoseira crinita

Three acyclic diterpenes have been isolated from the brown alga Cystoseira crinita and characterized as (2E,10E)-1,6-dihydroxy-7-methylene-13-keto-3,11,15-trimethylhexadeca-2,10,14-triene, (2E,5E,10E)-1,7-dihydroxy-13-keto-3,7,11,15-tetramethylhexadeca-2,6,10,14-tetracne and (2E, 1OE)-1-hydroxy-6,13-diketo-7-methylene-3,11,15-trimethylhexadeca-2,10,14-triene.     

Metabolism of PGI2 by 15-hydroxyprostaglandin-dehydrogenase and Δ13-reductase in different vascular beds of the cat in vivo

The metabolism of endogenous PGI₂ (released by angiotensin II or bradykinin) and exogenous PGI₂ by 15-hydroxy-PG-dehydrogenase and Δ¹³-reductase was studied in five different vascular beds of the anaesthetized cat. Plasma concentrations of 6-keto-PGF_1α (the product of spontaneous hydrolysis of PGI₂) and 6,15-diketo-13,14-dihydro-PGF_1α (the metabolite formed from PGI₂ by 15-hydroxy-PG-dehydrogenase and Δ¹³-reductase) were determined in the efferent vessels of the respective vascular beds by specific radioimmunoassays.No major metabolism of PGI₂ by 15-hydroxy-PG-dehydrogenase and Δ¹³-reductase was detected in the head and the hindlimbs of the cat. In the lung exogenous (circulating) PGI₂ was not metabolized, whereas PGI₂ synthetized in the lung itself was converted to 6,15-diketo-13,14-dihydor-PGF_1α. No significant amounts of 6,15-diketo-13,14-dihydro-PGF_1α-immunoreactivity were detected in hepatic venous blood after infusion of PGI₂ into the portal vein. However as also no 6-keto-PGF_1α was found, the liver seems to efficiently extract PGI₂ from the circulation. The cat kidney had the highest capacity of all vascular beds investigated to release endogenous and exogenous PGI₂ as 6-15-diketo-13,14-dihydro-PGF_1α. In other organs (vascular beds) investigated PGI₂ is either metabolized less efficiently by the 15-hydroxy-PG-dehydrogenase or further transformed to other metabolites.     

Metabolism of eicosa-11,14-dienoic acid in rat testes. Evidence for delta8-desaturase activity

The metabolism of [14C]eicosa-11,14-dienoic acid was investigated in rat testes in vivo and in vitro. Intratesticular injection of [1-14C]eicosa-11,14-dienoic acid resulted in the appearance of radioactivity (4-30% of 14C in total fatty acids) in 20-carbon trienoic fatty acids and a small amount (2-3.5%) in arachidonic acid. Analysis of the 20-carbon trienoic acid fraction by ozonolysis indicated that 15 to 34% of the 14C in this fraction was in an 8-carbon fragment originating from eicosa-8,11,14-trienoic acid. The rest (66 to 84%) was in a 5-carbon fragment, presumably originating from eicosa-5,11,14-trienoic acid. Incubation of testicular tissue minces or microsomes with [1-14C]eicosa-11,14-dienoic acid yielded labeled eicosa-8,11,14- and eicosa-5,11,14-trienoic acids in proportions similar to those obtained in vivo. Added unlabeled acetate had no effect on the formation of [14C]eicose-8,11,14-trienoic acid in vitro. Therefore, it is unlikely that the labeled eicosa-8,11,14-trienoic acid arose from elongation of octadeca-6,9,12-trienoic acid with labeled acetate derived from bio-oxidation of the labeled substrate. These results are compatible with a limited desaturation of eicosa-11,14-dienoic acid to eicosa-8,11,14-trienoic acid and provide evidence for delta8 desaturate activity in rat testis.     

Metabolism of PGI2 by 15-hydroxyprostaglandin-dehydrogenase and Δ-reductase in different vascular beds of the cat in vivo

The metabolism of endogenous PGI₂ (released by angiotensin II or bradykinin) and exogenous PGI₂ by 15-hydroxy-PG-dehydrogenase and Δ¹³-reductase was studied in five different vascular beds of the anaesthetized cat. Plasma concentrations of 6-keto-PGF_1α (the product of spontaneous hydrolysis of PGI₂) and 6,15-diketo-13,14-dihydro-PGF_1α (the metabolite formed from PGI₂ by 15-hydroxy-PG-dehydrogenase and Δ¹³-reductase) were determined in the efferent vessels of the respective vascular beds by specific radioimmunoassays.No major metabolism of PGI₂ by 15-hydroxy-PG-dehydrogenase and Δ¹³-reductase was detected in the head and the hindlimbs of the cat. In the lung exogenous (circulating) PGI₂ was not metabolized, whereas PGI₂ synthetized in the lung itself was converted to 6,15-diketo-13,14-dihydor-PGF_1α. No significant amounts of 6,15-diketo-13,14-dihydro-PGF_1α-immunoreactivity were detected in hepatic venous blood after infusion of PGI₂ into the portal vein. However as also no 6-keto-PGF_1α was found, the liver seems to efficiently extract PGI₂ from the circulation. The cat kidney had the highest capacity of all vascular beds investigated to release endogenous and exogenous PGI₂ as 6-15-diketo-13,14-dihydro-PGF_1α. In other organs (vascular beds) investigated PGI₂ is either metabolized less efficiently by the 15-hydroxy-PG-dehydrogenase or further transformed to other metabolites.     

The contribution of olfactory receptor neurons to the perception of pheromone component ratios in male redbanded leafroller moths

Summary (Z)-11-tetradecenyl acetate (Z-11, 14:AC) must be in a 1009 ratio with (E)-11-tetradecenyl acetate (E-11,14:AC) to produce maximal wing fanning and attraction in male redbanded leafrollers. Earlier electrophysiological studies had indicated that mixtures of these pheromone components elicited responses from olfactory receptor neurons that appeared to differ from those expected on the basis of the responses to the individual components. Here we evaluate whether the behavioral sensitivity to particular ratios of Z- and E-11,14:AC has a correlate in the response properties of olfactory receptor neurons.The stimuli included the ratios of Z- and E-11, 14:AC used in earlier behavioral work plus several different mixtures of the seven components found in the pheromone blend, and equivalent amounts of the individual components. These stimuli were presented over a range of intensities to individual trichoid sensilla on the male antenna. In common with earlier results, the receptor neuron with the larger amplitude action potential responded most strongly to Z-11,14:AC, whereas the companion receptor neuron in the sensillum responded most strongly to E-11,14:AC. In contrast with earlier results, each receptor neuron responded exclusively to its own most effective stimulus, without regard to the presence of any other compound. They failed to respond uniquely to any of the other five compounds in the female pheromone blend, or to any of the tested combinations of these compounds. These minor components also failed to modulate the responses elicited in receptor neurons by appropriate ratios of Z- and E-11,14:AC. Thus, the responses of the two types of olfactory receptor neurons found in trichoid sensilla failed to show an optimum at the pheromone ratio known to elicit peak behavioral activity.Abbreviation RBLR redbanded leafroller moth     

A New Cyclic Octopeptide from Schnabelia oligophylla

From the methanol extract of the whole plant of Schnabelia oligophylla Hand.-Mazz. (Lamiaceae), a new cyclic octopeptide, named schnabepeptide (1), was isolated by silica gel chromatography. Its structure was elucidated by spectroscopic analyses and the absolute configuration of the amino acid units, except for proline and glycine, were assigned by chiral HPLC analysis. Bio-assay showed that schnabepeptide (1) exhibited an immunosuppression activity on T/B lymphocytes. Along with the new compound, seven known compounds, octadeca-9,16-dioxo-10(E),12(Z),14(E)-trienoic acid (2), 12,16-epoxy-11,14-dihydroxy-17(15→16),18(4→3)-diabeo-abieta-3,5,8,11,13,15-hexene-2,7-dione (teuvincenone F, 3), abscisic acid (4), β-sitosterol (5), daucosterol (6), stigmasteryl 3-O-β- D -glucopyranoside (7) and palmitic acid (8), were also isolated from this plant.     

Keto fatty acids not containing doubly allylic methylenes are lipoxygenase substrates

The soybean lipoxygenase I oxygenates the unusual substrate 12-keto-(9Z)-octadecenoic acid methyl ester as indicated by oxygen uptake and spectral changes of the incubation mixture. The main oxygenation products have been isolated by HPLC and identified as 9,12-diketo-(10E)-octadecenoic acid methyl ester and 12-keto-(10E)-dodecenoic acid methyl ester by UV and IR spectroscopy, cochromatography with an authentic standard, gas chromatography/mass spectroscopy, and 1H NMR. In the formation of both compounds the oxygenase and hydroperoxidase activities of the enzyme appear to be involved. These data and the earlier results on the oxygenation of furanoic fatty acids (Boyer et al., 1979) indicate that the lipoxygenase reaction is not restricted to substrates containing a 1,4-pentadiene structure.     

Peroxyl-Radical Reaction of Retinyl Acetate in Solution

Retinyl acetate suppressed the free radical-induced oxidation of methyl linoleate. Retinyl acetate was reacted with an alkylperoxyl radical in two solvent systems, methanol and benzene. The alkylperoxyl radical was generated by the thermal decomposition of a free radical initiator, 2,2′-azobis(2,4-dimethylvaleronitrile), at 37°C. The reaction products were isolated by HPLC and their structures were identified. The main product in methanol was 14-hydroxy-13-methoxyretinyl acetate in addition to some minor products. The reaction in benzene gave some products with low yields. They were 5,6-epoxyretinyl acetate, 11,14-epoxyretinyl acetate, and 5,6,11,14-diepoxyretinyl acetate. The results indicate that retinyl acetate is capable of scavenging peroxyl radicals by its conjugated polyene structure.     

Genetic regulation of pathogenicity and virulence factors in bacteria Erwinia carotovora subsp. atroseptica: identification of kduD gene

A mutant that cannot utilize pectin substances of plant cell walls was obtained via insertion of mini-mini-Tn5xylE transposon into the chromosome of phytopathogenic bacteria Erwinia carotovora subsp. atroseptica. The inability of mutant cells to utilize these substrates was caused by a failure to accomplish the catabolism of unsaturated digalacturonic acid (UDA). Study of enzymatic activities has established that mutant bacteria lost the ability to produce 2,5-diketo-3-deoxygluconate dehydrogenase, an enzyme of intracellular UDA utilization. Molecular cloning of the mutant gene was conducted, and its nucleotide sequence was determined. It was shown that the nucleotide sequence of this gene had an 82% homology with the sequence of Erwinia chrysanthemi EC3937 kduD gene encoding 2,5-diketo-3-deoxygluconate dehydrogenase. The intergene kdul-kduD region in bacteria Erwinia carotovora subsp. atroseptica is shorter in length by 98 nucleotides than the corresponding region of Erwinia chrysanthemi and does not contain promoter sequences. The kduD gene was located at 126.8 min of the Erwinia carotovora subsp. atroseptica genetic map.     

A novel leukotriene formed by transpeptidation of leukotriene E

A new leukotriene 5(S)-hydroxy-6(R)-$\text{S}$-γ-glutamylcysteine-7,9-$\text{trans}$-11,14-$\text{cis}$-eicosatetraenoic acid (leukotriene F₄) was isolated after incubating leukotriene E₄ with γ-glutamyltranspeptidase and glutathione. Leukotriene F₄ induced contractions of the isolated quinea pig ileum and was less potent in this respect than leukotriene E₄.