Microbial metabolism of some 2,5-substituted thiophenes

2,5-Dialkylthiophenes are found in bitumens and crude oils, and previous studies showed that bacterial metabolism of some with a methyl substituent lead to the formation of 5-methyl-2-thiophenecarboxylic acid, which persisted in the culture medium (Fedorak PM & Peakman TM 1992 Biodegradation 2: 223–236). The objectives of this investigation were to study the further metabolism of this acid, and of two dialkylthiophenes, 2,5-diundecylthiophene and 2-(3,7-dimethyloctyl)-5-methylthiophene. Undefined, oil-degrading mixed cultures were used. 5-Methyl-2-thiophenecarboxylic acid was oxidized to 2,5-thiophenedicarboxylic acid which was identified by gas chromatography-mass spectrometry (GC-MS). This dicarboxylic acid was degraded and supported the growth of a mixed microbial population, and approximately 50% of the sulfur in this substrate was detected as sulfate in the medium at the end of the 15-day incubation time. Mixed cultures were incubated with 2,5-diundecylthiophene or 2-(3,7-dimethyloctyl)-5-methylthiophene as their sole carbon source, and at various times some of these were freezedried and the residues were treated to form methyl esters of any carboxylic acids produced. GC-MS analyses showed the presence of several dicarboxylic acids, indicating that both alkyl groups were oxidized. A small amount of the dimethyl ester of 2,5-thiophenedicarboxylic acid was detected in the culture grown on 2,5-diundecylthiophene, and 37% of the sulfur from this dialkylthiophene was detected as sulfate in the medium after 35 days of incubation.     

Microbiological degradation of bile acids. Metabolites formed from 3-(3a alpha-hexahydro-7a beta-methyl-1,5-dioxoindan-4 alpha-yl) propionic acid by Streptomyces rubescens.

1. The metabolism of 3-(3a alpha-hexahydro-7a beta-methyl-1,5-dioxoindan-4 alpha-yl)propionic acid (III), which is a possible precursor of 2,3,4,6,6a beta, 7,8,9,9a alpha,9b beta-decahydro-6a beta-methyl-1H-cyclopenta[f]quinoline-3,7-dione (II) formed from cholic acid (I) by streptomyces rubescens, was investigated by using the same organism. 2. This organism effected amide bond formation, reduction of the carbonyl groups, trans alpha beta-desaturation and R-oriented beta-hydroxylation of the propionic acid side chain and skeleton cleavage, and the following metabolites were isolated as these forms or their derivatives: compound (II), 1,2,3,4 a beta,-5,6,6a beta,7,8,9a alpha,9b beta-dodecahydro-6a beta -methylcyclopental[f][1]benzopyran-3,7-dione (IVa), (1R)-1,2,3,4a beta,5,6,6a beta,7,8,9.9a alpha,9b beta-dodecahydro-1-hydroxy-6a beta-methylcyclopenta[f][1]benzopyran-3,7-dione (IVb), (E)-3-(3aalpha-hexahydro-5 alpha-hydroxy-7a beta-methyl-l-oxo-indan-4 alpha-yl)prop-2-enoic acid (V), (+)-(5R)-5-methyl-4-oxo-octane-1,8-dioic acid (VI), 3-(4-hydroxy-5-methyl-2-oxo-2H-pyran-6-yl)propionic acid (VII) and 3-(3a alpha-hexahydro-1 beta-hydroxy-7a beta-methyl-5-oxoindan-4 alpha-yl)propionic acid (VIII). The metabolites (IVb), (V), (VI) and (VII) were new compounds, and their structures were established by chemical synthesis. 3. The question of whether these metabolites are true degradative intermediates is discussed, and a degradative pathway of compound (III) to the possible precursor of compound (VII), 7-carboxy-4-methyl-3,5-dioxoheptanoyl-CoA (IX), is tentatively proposed. The further degradation of compound (IX) to small fragments is also considered.     

Antiparasitic activity of prenylated benzoic acid derivatives from Piper species

Fractionation of dichloromethane extracts from the leaves of Piper heterophyllum and P. aduncum afforded three prenylated hydroxybenzoic acids, 3-[(2E,6E,10E)-11-carboxy-3,7,15-trimethyl-2,6,10,14-hexadecatetraenyl)-4,5-dihydroxybenzoic acid, 3-[(2E,6E,10E)-11-carboxy-13-hydroxy-3,7,15-trimethyl-2,6,10,14-hexadecatetraenyl]-4,5-dihydroxybenzoic acid and 3-[(2E,6E,10E)-11-carboxy-14-hydroxy-3,7,15-trimethyl-2,6,10,15-hexadecatetraenyl]-4,5-dihydroxybenzoic acid, along with the known compounds, 4,5-dihydroxy-3-(E,E,E-11-formyl-3,7,15-trimethyl-hexadeca-2,6,10,14-tetraenyl)benzoic acid (arieianal), 3,4-dihydroxy-5-(E,E,E-3,7,11,15-tetramethyl-hexadeca-2,6,10,14-tetraenyl)benzoic acid, 4-hydroxy-3-(E,E,E-3,7,11,15-tetramethyl-hexadeca-2,6,10,14-tetraenyl)benzoic acid, 3-(3,7-dimethyl-2,6-octadienyl)-4-methoxy-benzoic acid, 4-hydroxy-3-(3,7-dimethyl-2,6-octadienyl)benzoic acid and 4-hydroxy-3-(3-methyl-1-oxo-2-butenyl)-5-(3-methyl-2-butenyl)benzoic acid. Their structures were elucidated on the basis of spectroscopic data, including homo- and heteronuclear correlation NMR experiments (COSY, HSQC and HMBC) and comparison with data reported in the literature. Riguera ester reactions and optical rotation measurements established the compounds as racemates. The antiparasitic activity of the compounds were tested against three strains of Leishmania spp., Trypanosoma cruzi and Plasmodium falciparum. The results showed that 3-(3,7-dimethyl-2,6-octadienyl)-4-methoxy-benzoic acid exhibited potent and selective activity against L. braziliensis (IC₅₀ 6.5 μg/ml), higher that pentamidine used as control. Moreover, 3-[(2E,6E,10E)-11-carboxy-3,7,15-trimethyl- 2,6,10,14-hexadecatetraenyl)-4,5-dihydroxybenzoic acid and 4-hydroxy-3-(3-methyl-1-oxo-2-butenyl)-5-(3-methyl-2-butenyl)benzoic acid showed moderate antiplasmodial (IC₅₀ 3.2 μg/ml) and trypanocidal (16.5 μg/ml) activities, respectively.     

Microbial Transformation of Terpenoids. I. Indentification of Metabolites Produced by a Pseudomonad from Citronellal and Citral

A bacterium capable of utilizing citronellal or citral as the sole source of carbon and energy has been isolated from soil by the enrichment culture technique. It metabolizes citronellal to citronellic acid (65%), citronellol (0.6%), dihydrocitronellol (0.6%), menthol (0.75%), and 3,7-dimethyl-1,7-octane diol (1.7%). The metabolites of citral were geranic acid (62%), 6-methyl-5-heptanoic acid (0.5%), 3-methyl-2-butenoic acid (1%), and 1-hydroxy-3, 7-dimethyl-6-octen-2-one (0.75%).     

Complementary microbial approaches for the preparation of optically pure aromatic molecules

Different strategies for stereoselective microbial preparation of various chiral aromatic compounds are described. Optically pure 2-methyl-3-phenyl-1-propanol, ethyl 2-methyl-3-phenylpropanoate, 2-methyl-3-phenylpropanal, 2-methyl-3-phenylpropionic acid and 2-methyl-3-phenylpropyl acetate have been prepared using different microbial biotransformations starting from different prochiral and/or racemic substrates. (S)-2-Methyl-3-phenyl-1-propanol and (S)-2-methyl-3-phenylpropanal were prepared by biotransformation of 2-methyl cinnamaldehyde using the recombinant strain Saccharomyces cerevisiae BY4741ΔOye2Ks carrying a heterologous OYE gene from Kazachstania spencerorum. (R)-2-Methyl-3-phenylpropionic acid was obtained by oxidation of racemic 2-methyl-3-phenyl-1-propanol with acetic acid bacteria. Kinetic resolution of racemic 2-methyl-3-phenylpropionic acid was carried out by direct esterification with ethanol using dry mycelia of Rhizopus oryzae CBS 112.07 in organic solvent, giving (R)-ethyl 2-methyl-3-phenylpropanoate as major enantiomer. Finally, (R,S)-2-methyl-3-phenylpropyl acetate was enantioselectively hydrolysed employing different bacteria and yeasts having cell-bound carboxylesterases with prevalent formation of (R)- or (S)-2-methyl-3-phenyl-1-propanol, depending on the strain employed.     

Microbiological degradation of bile acids. Nitrogenous hexahydroindane derivatives formed from cholic acid by Streptomyces rubescens.

The metabolism of cholic acid (I) by Streptomyces rubescens was investigated. This organism effected ring A cleavage, side-chain shortening and amide bond formation and gave the following metabolites: (4R)-4-[4alpha-(2-carboxyethyl)-3aalpha-hexahydro-7abeta-methyl-5-oxoindan-1 beta-yl]valeric acid (IIa) and its mono-amide (valeramide) (IIb); and 2,3,4,6, 6abeta,7,8,9,9aalpha,9bbeta-decahydro-6abeta-methyl-1H-cyclopenta[f]quinoline-3,7-dione(IIIe)and its homologues with the beta-oriented side chains, valeric acid, valeramide, butanone and propionic acid, in the place of the oxo group at C-7, i.e.compounds (IIIa), (IIIb), (IIIc) and (IIId) respectively. All the nitrogenous metabolites were new compounds, and their structures were established by partial synthesis except for the metabolite (IIIc). The mechanism of formation of these metabolites is considered. A degradative pathway of cholic acid (I) into the metabolites is also tentatively proposed.     

Some new derivatives of organozirconium(IV) and organotitanium(IV) with thiophenecarboxylic acids

The complexes of the type Cp₂M(3-TC)Cl, Cp₂M(3-TC)₂, Cp₂M(3-TA)Cl, Cp₂M(3-TA)₂, Cp₂M(2-TB)Cl, Cp₂M(2-TB)₂ [where Cp = cyclopentadienyl, M = Zr or Ti] were synthesized by the reactions of dichlorobis(cyclopentadienyl)zirconium(IV) and dichlorobis(cyclopentadienyl)titanium(IV) with 3-thiophenecarboxylic acid (3-TCH), 3-thiopheneacetic acid (3-TAH) and 2-thiophenebutyric acid (2-TBH) respectively in different stoichiometric ratios. The new complexes were characterized by their elemental analysis, ¹H NMR, IR, and electronic spectral data.     

Synthesis and evaluation of novel 2-butyl-4-chloro-1-methylimidazole embedded chalcones and pyrazoles as angiotensin converting enzyme (ACE) inhibitors

A series of novel 2-butyl-4-chloro-1-methylimidazole embedded aryl and heteroaryl derived chalcones and pyrazoles were synthesized and evaluated for their angiotensin converting enzyme (ACE) inhibitory activity. The condensation of 2-butyl-4-chloro-1-methylimidazole-5-carboxaldehyde with various aryl and heteroaryl methyl ketones in the presence of 10% aqueous NaOH in methanol proceeded efficiently to give the respective chalcones in very good yields. Further, the reaction of chalcones with hydrazine hydrate in acetic acid gave substituted pyrazole analogues. Screening all 36 new compounds using ACE inhibition assay, resulted chalcones with better ACE inhibitory activity compared to the respective pyrazole analogues. Among the chalcones 4a-r, three compounds, (E)-3-(2-butyl-4-chloro-1-methyl-1H-imidazol-5-yl)-1-(5-chlorothiophen-2-yl)prop-2-enone 4i, (E)-3-(2-butyl-4-chloro-1-methyl-1H-imidazol-5-yl)-1-(1H-pyrrol-2-yl)prop-2-enone 4l, (E)-3-(2-butyl-4-chloro-1-methyl-1H-imidazol-5-yl)-1-(dibenzo[b,d] thiophen-2-yl)prop-2-enone 4q were resulted as most active ACE inhibitors with IC(50) of 3.60 μM, 2.24 μM, and 2.68 μM, respectively.     

Comparative analysis of nonvolatile and volatile metabolites in Lichtheimia ramosa cultivated in different growth media

Lichtheimia ramosa is one of the predominant filamentous fungi in Korean traditional nuruk. The nonvolatile and volatile metabolites of L. ramosa cultivated in three growth media: complete medium (CM), potato dextrose broth (PDB), and sabouraud dextrose broth (SDB), were investigated and compared. Among nonvolatile metabolites, serine, lysine, and ornithine increased in CM and PDB cultivated with L. ramosa during the exponential phase. In addition, glucose level increased in CM whereas decreased in PDB and SDB. The major volatile metabolites in the extract samples were acetic acid, ethanol, 3-methyl-2-buten-1-ol, 2-phenylethanol, ethylacetate, 2-furaldehyde, 5-(hydroxymethyl)-2-furaldehyde, 2,3-dihydro-3,5,-dihydroxy-6-methyl-4H-pyran-4-one, and α-humulene. In particular, the levels of volatile metabolites related to makgeolli (e.g., acetic acid, ethanol, and ethyl acetate) were highest in extracts cultivated in CM. On the other hand, the level of 2-phenylethanol was relatively higher in PDB and SDB, possibly due to there being more phenylalanine present in the biomass sample in media.     

Microbial transformation of geraniol and nerol by Botrytis cinerea

Summary Biotransformation of geraniol 1A and nerol 1B was studied with four strains of Botrytis cinerea and three growth media. Using grape must predominant conversion of 1A/1B to E-3,7-dimethyl-2-octen-1,8-diol 5 and 2Z,6E-3,7-dimethyl-2,6-octadien-1,8-diol 16B was observed. However, with one strain and 1A, E-2-methyl-2-hepten-6-one-1-ol 2B, 7-hydroxy-6-methyl-2-heptanone 3 and p-menth-1-ene-9-ol 7 were identified as major metabolites. As further fungal bioconversion products of 1A/1B were detected: Z-2-methyl-2-hepten-6-one-1-ol 2A, 2E,6Z-, 2E,6E-and 2Z,6Z-3,7-dimethyl-2,6-octadien-1,8-diol 4A/4B/16A, Z-3,7-dimethyl-2-octen-1,8-diol 17, 3,7-dimethyl-1,8-octandiol 6, 2E,6E-8-hydroxy-2,6-dimethyl-2,6-octadienal 8, geranial and neral 9, 18, citronellol 10, Z- and E-2,6-dimethyl-2,7-octadien-1,6-diol 13A/13B, 6-hydroxy-2,6-dimethyl-2,7-octadienal 14 as well as 2,6-dimethyl-7-octen-1,6-diol 15. Using synthetic growth medium again -hydroxylation reactions were observed, but 2-methyl-2-hepten-6-one 11 and 7 were also identified as major bioconversion products of 1A and 1B, respectively. Additionally, 2-methyl-2-hepten-6-ol 12 was detected and, using 1B, also traces of 2Z,6E-8-hydroxy-2,6-dimethyl-2,6-octadienal 19 and two 3,9-epoxy-p-menth-1-ene isomers 20A/20B were found. Addition of small amounts of grape must to the synthetic medium (1:700 to 5:700) influenced both the yields of metabolites and their qualitative and quantitative distribution. Identifications of biotransformation products of 1A/1B were performed by capillary gas chromatography (HRGC) and coupled HRGC techniques, i.2. on-line-mass spectrometry (HRGC-MS) and-Fourier transform infrared spectroscopy (HRGC-FTIR) after extractive sample preparation.     

Alkylglucosides with isoprenoid-type hydrophobic chains-effects of hydrophobic chain size on the aqueous phase behavior

Aqueous phase diagrams were constructed for two new alkylglucosides with isoprenoid-type hydrophobic chains, viz. 1-O-beta-(3,7-dimethyloctyl)-D-glucopyranoside, beta-Glc(Ger), and 1-O-beta-(3,7,11,15-tetramethylhexadecyl)-D-glucopyranoside, beta-Glc(Phyt). In a low concentration regime, from 0.17 to 34 wt.% beta-Glc(Ger), the beta-Glc(Ger)/water system exhibits two phase, a dilute (L1dil) and a concentrated isotropic phase (L1con), coexistence region. Above about 62 wt.% beta-Glc(Ger), an Lalpha phase is formed. The extent of the L1dil + L1conc two-phase region decreases as temperature increases and totally disappears above 130 degrees C, exhibiting an upper critical temperature. The beta-Glc(Phyt)/water system exhibits an Lalpha phase above 78 wt.% surfactant below which, an Lalpha + water two-phase region appears. One notable feature of these compounds is their low values of Krafft-eutectic temperature, TK, e.g. the value of TK for beta-Glc(Phyt) is below 0 degrees C although the total number of carbon atoms in the hydrophobic chain is as large as 20.     

Utilization of Bacterial Xanthine Oxidase for Inorganic Phosphorus Determination

Two host-specific phytotoxic metabolites, AK-toxin I and II, were isolated from a culture broth of Alternaria alternata Japanese pear pathotype, the fungus causing black spot disease of susceptible Japanese pear cultivars. From chemical, spectral and X-ray crystallographic data, AK-toxin I was characterized as 8-(2′S, 3′S)-2′-acetylamino-3′-methyl-3′-phenyl-propionyloxy]-(8R,9S)-9,10-epoxy-9-methyl-deca-(2E,4Z,6E)-trienoic acid. The structure of AK-toxin II was also assigned to be 3′-demethyl derivative of AK-toxin I by comparing the spectral data with those of AK-toxin I.     

Strategy and Design of Novel Reagents for the Fluorometric Analysis of Biomolecules

This article covers molecular designs to develop several new fluorometric reagents and their applications to increase the sensitivities up to the picomole level using HPLC for the measurement of biomolecules. The methods were designed to demonstrate the physiological activities, for example (1) N-(9-acridinyl)maleimide (NAM) for the measurement of SH, –S–S–, and sulfite such as cysteine, (2) diphenyl-1-pyrenylphosphine (DPPP) for the hydroperoxides in lipids, serum, tissues, and foodstuffs, (3) 9-bromomethylacridine (9-BrMA), (4) 2-(anthracene-2,3-dicarboxylimide)ethyltrifluoromethane sulfonate (AE-OTf) for carboxylic acids, and (5) The chiral fluorometric labelling reagent (S)-( + )-2-tert-butyl-2-methyl-1,3-benzodioxole-4-carboxylic acid (TBMB) to identify the chiralities of amino acids, sugars, and mono- and diacylglycerols.     

Absorption,Translocation and Metabolism of 2-tert-Butyl-4-(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one (Oxadiazon) in Rice Plants

Absorption, translocation and metabolism of 2-tret-butyl-4-(2,4-dichloro-5-isopro-poxyphenyl)-Δ²-1,3,4-oxadiazolin-5-one (oxadiazon) in rice plants were investigated. Three types of ¹⁴C-labeled oxadiazon were used in this study. ¹⁴C-Labeled oxadiazon was applied to soil under submerged conditions and plants were taken for the preparations at various stages of growth and development. Oxadiazon was translocated remarkably to shoots and accumulated in the lower leaves and stems. A small portion of oxadiazon intaken in plants was translocated to head parts. Oxadiazon was chemically transformed in plants to produce dealkylated compounds, oxidized alcohol and carboxylic acid as metabolites. In addition, two unidentified metabolites were detected, one of which was translocated to head parts from leaves and stems. Translocation and accumulation of oxadiazon and its metabolites were discussed in relation to physiological conditions of rice plants.     

Geranyl flavonoids from the leaves of Artocarpus altilis

Five geranyl dihydrochalcones, 1-(2,4-dihydroxyphenyl)-3-{4-hydroxy-6,6,9-trimethyl-6a,7,8,10a-tetrahydro-6H-dibenzo[b,d]pyran-5-yl}-1-propanone (2), 1-(2,4-dihydroxyphenyl)-3-[3,4-dihydro-3,8-dihydroxy-2-methyl-2-(4-methyl-3-pentenyl)-2H-1-benzopyran-5-yl]-1-propanone (4), 1-(2,4-dihydroxyphenyl)-3-[8-hydroxy-2-methyl-2-(3,4-epoxy-4-methyl-1-pentenyl)-2H-1-benzopyran-5-yl]-1-propanone (5), 1-(2,4-dihydroxyphenyl)-3-[8-hydroxy-2-methyl-2-(4-hydroxy-4-methyl-2-pentenyl)-2H-1-benzopyran-5-yl]-1-propanone (8), and 2-[6-hydroxy-3,7-dimethylocta-2(E),7-dienyl]-2',3,4,4'-tetrahydroxydihydrochalcone (9), along with four known geranyl flavonoids (1, 3, 6, 7), were isolated from the leaves of Artocarpus altilis. Their structures were established by spectroscopic means and by comparison with the literature values. Compounds 2, 4, and 9 exhibited moderate cytotoxicity against SPC-A-1, SW-480, and SMMC-7721 human cancer cells.     

The metabolism of 2,6-di-tert.-butyl-4-hydroxymethylphenol (Ionox 100) in the dog and rat

1. A single oral dose of [(14)C]Ionox 100 to rats is almost entirely eliminated in 11 days: 89.1-107.2% of the (14)C is excreted and 0.29+/-0.02% of the dose is present in the carcass plus viscera after removal of the gut. Rats exhibit an individual variation in the elimination pattern, 15.6-70.8% of (14)C being excreted in the urine and 75.2-27.0% in the faeces during 11 days. 2. After the oral administration of [(14)C]Ionox 100 to dogs, 87.1-90.3% of the (14)C is excreted in the faeces and urine during 4 days. 3. Dogs and rats do not show a species difference in this pattern of elimination. 4. The rate of elimination from dogs and rats given a single dose of Ionox 100 is not affected by the size of the dose and the presence of triglyceride fat in the diet. 5. Ionox 100 is completely metabolized in dogs and rats: unchanged Ionox 100 is absent from the urine and faeces, and from the carcass when elimination is complete. In rats, 3,5-di-tert.-butyl-4-hydroxybenzoic acid accounts for 50-85% of a dose of Ionox 100 and (3,5-di-tert.-butyl-4-hydroxybenzoyl beta-d-glucopyranosid)uronic acid for 47-10%; in dogs, the unconjugated acid accounts for 85% and the ester glucuronide for 10-12%. 3,5-Di-tert.-butyl-4-hydroxyhippuric acid is not formed. Other metabolites, which have been detected in small quantity in the faeces and urine of animals dosed with Ionox 100, have not been identified. 6. 3,5-Di-tert.-butyl-4-hydroxybenzoic acid and (3,5-di-tert.-butyl-4-hydroxybenzoyl beta-d-glucopyranosid)uronic acid are also the major metabolites of Ionol (2,6-di-tert.-butyl-p-cresol) in rats. 7. The elimination of Ionox 100 metabolites from rats is faster than that of Ionol and its metabolites. Unlike Ionol, unchanged Ionox 100 could not be detected in the bodies of these animals.     

High-performance liquid chromatographic determination of the polar metabolites of nifedipine in plasma, blood and urine

A relatively simple reversed-phase high-performance liquid chromatographic method for the determination of the polar metabolites of nifedipine in biological fluids is described. After conversion of 2-hydroxymethyl-6-methyl-4-(2-nitrophenyl)pyridine-3,5-dicarboxylic acid 5-methyl ester (IV) into 5,7-dihydro-2-methyl-4-(2-nitrophenyl)-5-oxofuro[3,4-b]pyridine-3-carboxylic acid methyl ester (V) by heating under acidic conditions, V was extracted with n-pentane—dichloromethane (7:3) and analysed on a C₁₈ column with ultraviolet detection. Subsequently, 2,6-dimethyl-4-(2-nitrophenyl)-3,5-pyridinedicarboxylic acid monomethyl ester (III) was extracted with chloroform and analysed on the same system. Limits of determination in blood were 0.1 μg/ml for III and 0.05 μg/ml for IV and V; these limits were two to ten times higher for urine. This inter-assay variability was always less than 7.5%.     

Xanthones from Garcinia smeathmannii (Oliver) and their antimicrobial activity

Two new xanthones, smeathxanthone A (1) (2-(3,7-dimethyl-2,6-octadienyl)-1,3,5,8-tetrahydroxyxanthone) and smeathxanthone B (2) (5,7,10-trihydroxy-2-methyl-2-(4-methylpent-3-enyl)[2H, 6H]pyrano[3,2-b]xanthen-6-one), have been isolated from the stem bark of Garcinia smeathmannii, and their structures elucidated on the basis of 1D and 2D NMR experiments. 1,3,5-Trihydroxyxanthone and 1,5-dihydroxyxanthone were also obtained. The compounds showed only modest activity against a range of bacteria and yeasts.     

Metabolism of O,O-Dipropyl S-[2-(2′-Methyl-1′-piperidinyl)-2-oxo-ethyl] Phosphorodithioate (C 19 490) in Paddy Rice

The fate of O,O-dipropyl S-[2-(2′-methyl-1′-piperidinyl)-2-oxo-ethyl] phosphorodithioate (C 19 490, piperophos) was followed in greenhouse-grown rice after application of 1.6 kg/ha ¹⁴C-labeled C 19 490 into the paddy water. At maturity the shoots contained 2.5 ppm and the hulled grains 0.16 ppm ¹⁴C-C 19 490 equivalents. Small amounts of unchanged C 19 490 were found in the shoots but none in the grains.

The main metabolites found were:- 2-(2′-methyl-1′-piperidiny])-2-oxo-ethane sulfonic acid, 2-(2?-methyl-1?-piperidinyl)-2-oxo-ethanoic acid and a fraction of polar unknown substances. O,O-Dipropyl S-[2-(2?-methyl-1′ -piperidinyl)-2-oxo-ethyl] phosphorothioate, 2-(2?-methyl-1?-piperidinyl)- 1-methyl-sulfinyl-2-oxo-ethane, 2-(2?-methyl-1?-piperidinyl)-1-methyl-sulfonyl-2-oxo- ethane, 2-methyl-piperidine and CO₂ were found in smaller amounts.     

Isoprenoid enzyme systems of silkworm. II. Formation of the juvenile hormone skeletons by farnesyl pyrophosphate synthetase II

Comparative substrate specificities of farnesyl pyrophosphate synthetases I and II purified from larvae of silkworm, Bombyx mori, were studied by use of the possible biosynthetic intermediates of juvenile hormones in the insect. In the presence of Mn2+ ions farnesyl pyrophosphate synthetase II showed higher activity than synthetase I and the corresponding enzyme from pig liver with the following substrate homologues: (Z)-3-methyl-2-pentenyl-, 3-ethyl-3-butenyl-, (2E,6Z)-3,7-dimethyl-2,6-nonadienyl-, and (2E,6Z)-3-ethyl-7-methyl-2,6-nonadienyl pyrophosphate. When (Z)-3-methyl-2-pentenyl-, 3-ethyl-3-butenyl-, and isopentenyl pyrophosphate were mixed and incubated with farnesyl pyrophosphate synthetase II, (2E,6E,10Z)-3,11-dimethyl-7-ethyl-2,6,10-tridecatrienyl-, (2E,6E,10Z)-3,7,11-trimethyl-2,6,10-tridecatrienyl, and a trace amount of (2E,6E,10Z)-3,7-diethyl-11-methyl-2,6,10-tridecatrienyl pyrophosphate, whose carbon skeletons were the same as those of juvenile hormone I, II, and O, respectively, were formed. (Z)-3-Methyl-2-pentenyl pyrophosphate was produced from 3-ethyl-3-butenyl pyrophosphate as a single product by the action of silkworm isopentenyl pyrophosphate isomerase, though the enzyme activity was much lower with this substrate than with the usual substrate, isopentenyl pyrophosphate.