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PubMed1985

Sequence specificity of mutagenesis in the cI gene of bacteriophage lambda.

Studies of DNA base sequence alterations have shown that for every agent the mutagenic process is specific with respect to the types of base changes induced and the location of the changes in the DNA. Analysis of the types of mutations produced by mutagenic agents can provide insight into the mechanism of mutation and can suggest which DNA lesions may be involved in the actual mutagenic event. We have developed a system for the analysis of chemically induced base sequence alterations in the cI repressor gene of bacteriophage lambda using DNA sequencing techniques. To illustrate the utility of this type of analysis, we present the results obtained with ultraviolet light (UV). Irradiation of target DNA with UV alone, or UV followed by photoreactivating light (which removes dimers), produces mostly transitions at pyrimidine-pyrimidine sites. Conversely, irradiation with 313 nm light plus acetophenone (which produces only thymine dimers) produces mostly transversions at low efficiency. This and other evidence suggests that the actual premutagenic UV lesion in E. coli may not be pyrimidine-pyrimidine dimers, but rather pyr(6-4)pyo photoproducts.

Bacteriophage lambda↗
PubMedDate not supplied

Propolis from Chilean matorral hives.

Viscidone (0.5%), vanillin, 3',4'-(methylendioxy)acetophenone, 3-ethoxy-4-methoxybenzaldehyde, cinnamic acid, 3-methoxy-4-hydroxymethyl ester were isolated from propolis of hives from Cuncumen. This is the first report on propolis composition of an arid and a Mediterranean type climate area.

Animals↗
PubMedDate not supplied

Volatile compounds in shoulder gland secretions of male flying foxes, genus Pteropus (Pteropodidae, Chiroptera).

The shoulder gland secretions of captive males of the Indian flying fox (Pteropus giganteus), the little golden-mantled flying fox (P. pumilus), the island flying fox (P. hypomelanus), and the large flying fox (P. vampyrus) were examined by gas chromatography-mass spectrometry. Sixty-five compounds, including hydrocarbons, carboxylic acids, alcohols, aldehydes, ketones, esters, and amides, were identified among the four species. Many of these compounds, such as squalene, cholesterol, and C5-C16 straight- and branched-chain carboxylic acids, are typical of tetrapod epidermal products. Aldehydes, which were detected in all four Pteropus species, and some straight- and branched-chain ketones, which were detected in P. hypomelanus and P. pumilus, are known from other mammalian skin glands. Acetophenone, 4-acetoxyacetophenone, and 4-hydroxyacetophenone were observed in P. pumilus; the last compound comprised 37.1% of the total ion current. 2,3-Butanediol, a prominent component (5.2-19.3%) in the secretions of P. giganteus, P. hypomelanus, and P. pumilus, and C10 and C12 isopropyl esters and C10-C14 1-methylbutyl esters, observed in P. hypomelanus and P. vampyrus, have not previously been reported from vertebrates. alpha-Methyl-4-methoxybenzyl alcohol and dihydro-5-phenyl-2(3H)-furanone, from P. giganteus and P. pumilus, are new natural products. 1-Chloro-3-methyl-2-butene, another new natural product, and five C5 compounds exhibiting a similar isoprenoid structure were observed in P. giganteus. Striking contrasts were observed in the chemical profiles of the species we examined, with even general chemical classes differentially represented among them.

Alcohols↗
PubMed2004

Beta-amyloid peptides induce mitochondrial dysfunction and oxidative stress in astrocytes and death of neurons through activation of NADPH oxidase.

Beta-amyloid (betaA) peptide is strongly implicated in the neurodegeneration underlying Alzheimer's disease, but the mechanisms of neurotoxicity remain controversial. This study establishes a central role for oxidative stress by the activation of NADPH oxidase in astrocytes as the cause of betaA-induced neuronal death. betaA causes a loss of mitochondrial potential in astrocytes but not in neurons. The mitochondrial response consists of Ca2+-dependent transient depolarizations superimposed on a slow collapse of potential. The slow response is both prevented by antioxidants and, remarkably, reversed by provision of glutamate and other mitochondrial substrates to complexes I and II. These findings suggest that the depolarization reflects oxidative damage to metabolic pathways upstream of mitochondrial respiration. Inhibition of NADPH oxidase by diphenylene iodonium or 4-hydroxy-3-methoxy-acetophenone blocks betaA-induced reactive oxygen species generation, prevents the mitochondrial depolarization, prevents betaA-induced glutathione depletion in both neurons and astrocytes, and protects neurons from cell death, placing the astrocyte NADPH oxidase as a primary target of betaA-induced neurodegeneration.

Amyloid beta-Peptides↗
PubMedDate not supplied

Oxygen uptake and involvement of superoxide radicals upon photolysis of ketones in air-saturated aqueous alcohol, formate, amine or ascorbic acid solutions.

The photolysis of acetophenone, benzophenone, 4-carboxybenzophenone and benzil was studied in air-saturated aqueous solution in the presence of alcohols. The overall reaction is an oxidation of 2-propanol to acetone. The quantum yield of oxygen uptake (Phi(-O(2))) increases with increasing 2-propanol concentration up to 0.9. The photoreaction can also be initiated by quenching of the ketone triplet state by ascorbic acid, formate or an amine e.g. triethylamine. Subsequent reactions of the involved radicals with oxygen yield the superoxide radical and eventually hydrogen peroxide. For the ketones in the presence of 3-30 mM ascorbic acid or triethylamine Phi(-O(2)) = 0.3-0.9. The specific properties of ketones, including 4-methoxyacetophenone and 2-acetonaphthone, the radicals involved and the pH and concentration dependences of Phi(-O(2)) are discussed.

Air↗
PubMed2002

Electroantennogram responses of Nilaparvata lugens (Homoptera: Delphacidae) to plant volatile compounds.

Electroantennogram (EAG) recordings were made from the plaque organ receptors of the rice brown plant hopper, Nilaparvata lugens (Stål). The receptors of the distal plaque organ of both male and female hoppers responded to the air from above chopped rice plants, and those of females gave a larger response. Female hoppers, tested with 27 plant volatiles, gave dose-related responses to 16 of the compounds, including a range of green leaf volatiles. The aliphatic aldehydes hexanal and (E)-2-hexenal elicited a larger response than a range of green leaf alcohols. Of the remaining compounds, acetophenone, benzaldehyde, ethyl and methyl benzoate, and amyl and isoamyl acetate were among the most effective in eliciting responses. Receptor recovery times showed some variation between compounds. A comparison of the dose-related response of 16 compounds in paraffin oil and in pentane showed that considerably larger responses were recorded when the highly volatile solvent pentane was used.

Animals↗
PubMed1997

Regulation of RANTES and ICAM-1 expression in murine mesangial cells.

Chemokines and adhesion molecules play a pivotal role in leukocyte infiltration during tissue injury. RANTES (regulated upon activation, normal T cell expressed and secreted) is a monocyte chemoattractant that induces the expression of CD11/CD18 integrins on leukocytes for which intercellular adhesion molecule-1 (ICAM-1) is the ligand. Both RANTES and ICAM-1 can be expressed by mesangial cells (MC) in culture and in glomeruli during immune injury. In this study, the role of reactive oxygen species (ROS) in the activation of RANTES and ICAM-1 in murine MC was examined. Tumor necrosis factor alpha (TNF-alpha) and aggregated immunoglobulin (aggr. Ig) G, which enhance ROS formation in MC, increased mRNA transcripts of both RANTES and ICAM-1. Thiol-containing free-radical scavengers N-acetyl cysteine, dimethyl- and tetramethylthiourea, or pyrrolidinedithiocarbamate abrogated the increase in mRNA for RANTES and ICAM-1 in response to TNF-alpha or IgG. Hydroxy-methoxy acetophenone, an inhibitor of NADPH-dependent oxidase, also attenuated RANTES and ICAM-1 in response to TNF-alpha or IgG. ROS generated by addition of xanthine oxidase and hypoxanthine induced RANTES and ICAM-1 expression, whereas hydrogen peroxide caused no response. Because cAMP can interfere with gene activation in MC, the effects of 8-Br-cAMP, forskolin, and prostaglandin E2 on mRNA levels were examined for RANTES and ICAM-1. These agents attenuated the response to IgG aggregates and also to superoxide generation. Finally, the effect of glucocorticoids, which are frequently used in glomerular immune injury, was examined. Dexamethasone decreased mRNA for both RANTES and ICAM-1 after stimulation with aggr. IgG or TNF-alpha. Both forskolin and dexamethasone also reduced the amount of RANTES protein secreted by MC in response to aggr. IgG. Only dexamethasone decreased RANTES secretion in response to TNF-alpha stimulation. The inhibitory effects of cAMP and dexamethasone may explain the beneficial effects of cAMP mimetics, such as prostaglandin E2 and glucocorticoid administration on glomerular inflammatory processes.

Animals↗
PubMed1994

Diurnal variations in olfactory sensitivity and the relationship to food intake.

At least a dozen studies have investigated the effects of food intake on olfactory sensitivity. Most studies reported the existence of food-related changes in sensitivity but the findings are highly discrepant. In the present study, earlier studies are reviewed, their shortcomings discussed, and the results of an experiment are reported. Using an air-dilution olfactometer, sensitivity to the odor of acetophenone was assessed throughout the day in seven subjects on four consecutive days, both with and without lunch. In the group data no consistent pattern of changes in sensitivity related to food intake was found, although some individual subjects showed a diurnal variation. Some suggestions are made enhancing the possibility that in the future a relationship between food intake and olfactory sensitivity may be observed.

Adult↗
PubMed1982

Characterization of the antifungal and antiprotozoal antibiotic partricin and structural studies on partricins A and B.

Partricin, a heptaene macrolide antibiotic, has been separated into three polyene components, partricins A, B and C, and one non-polyene component by countercurrent distribution. Treatment of partricin with base gave p-(methylamino)acetophenone and p-aminoacetophenone from partricins A and B, respectively, identifying both as members of the aromatic subgroup of the heptaene antibiotics. Both partricins A and B yield mycosamine on mild acid hydrolysis. NMR and mass spectral studies on products of ozonolysis or hydrogenolysis of acetyl derivatives provided evidence for the partial structures 1 approximately 9.

Antifungal Agents↗
PubMed1976

Identification of 17-methyl-18-norandrosta-5,13(17-dien-3beta-ol, the C19 fragment formed by adrenal side chain cleavage of a 20-aryl analog of (20S)-20-hydroxycholesterol.

Incubation of (20R)-20-phenyl-5-pregnene-3beta,20-diol, an aromatic analog of (23S)-20-hydroxycholesterol, with an adrenal mitochondrial preparation leads to the formation of four compounds: pregnenolone, phenol, a C8 ketone, acetophenone, and a nonpolar C19 compound. This latter compound has now been identified by reverse isotope dilution analysis and by gas chromatography/mass spectrometry as 17-methyl-18-norandrosta-5,13(17)-dien-3beta-ol. From these results it is evident that enzymatic fission of the C-17,20 bond of this synthetic derivative occurs. On the other hand, when (20S)-20-hydroxy[21-14C]cholesterol was used as substrate, the analogous cleavage did not take place. Thus, substitution of an aromatic group on C-20 facilitates side chain cleavage between that carbon atom and the nucleus whereas neither of the naturally occuring precursors, cholesterol or its 20-hydroxylated counterpart, are metabolized to a C8 fragment.

Adrenal Glands↗
PubMed1999

Synthesis and biological screening of new 1,3-diphenylpyrazoles with different heterocyclic moieties at position-4.

1,3-Diphenyl-1 H-pyrazole-4-carboxaldehyde (1) was reacted with barbituric acid, thiobarbituric acid, some activated nitriles and/or acetophenone to give the condensation products 2a, b, 3a-c and 4, respectively. The reaction of 1 with hydrazine hydrate, semicarbazide or thiosemicarbazide afforded the corresponding azomethines 5a-c. The compounds 3a, b, 4 and 5a, c were subjected for different sequence reactions to produce the title compounds. The antibacterial and antifungal activity of some selected derivatives were evaluated.

Anti-Bacterial Agents↗
PubMed1999

Identification of phase I metabolites of 3-methylindole produced by pig liver microsomes.

A study was conducted to investigate qualitative and quantitative aspects of the phase I metabolism of 3-methylindole (3MI) by porcine liver microsomes. Microsomal suspensions were prepared from the liver of 30 intact (uncastrated) male pigs. Metabolites produced in microsomal incubations were identified and quantitated with HPLC-UV, HPLC-fluorescence, and UV-spectral analysis; liquid chromatography-mass spectrometry (LC-MS) and NMR were used for the identification of a metabolite for which a reference compound was not available. The results showed that seven major metabolites of 3MI are produced by porcine microsomes, three of which had already been identified in pigs (3-OH-3-methyloxindole, 5-OH-3-methylindole, and 6-OH-3-methylindole). The other four major 3MI metabolites identified were 3-OH-3-methylindolenine, 3-methyloxindole, indole-3-carbinol, and 2-aminoacetophenone. On average, the metabolite that was produced in larger amounts was 3-OH-3-methylindolenine (45.1%), followed by the two oxindoles 3-methyloxindole (27.9%) and 3-OH-3-methyloxindole (18.5%). Average percentage of production of 6-OH-3-methylindole was 4.9%, whereas indole-3-carbinol accounted for 2.7% of all metabolites produced; 2-amino-acetophenone and 5-OH-3-methylindole were the metabolites produced in lesser amounts (0.5 and 0.3%, respectively). Large interindividual differences in the rate of production of all metabolites were observed. This variation could be attributed to differences in the activity and/or level of expression of phase I biotransformation enzymes and this issue should be further investigated.

Animals↗
PubMed2000

Synthesis and antitumor cytotoxicity evaluation of pyrido[4,3,2-de]quinolines and isoquinolino[6,5,4,3-cde]quinolines.

A series of novel pyrido[4,3,2-de]quinoline and isoquinolino[6,5,4,3-cde] quinoline compounds was synthesized and evaluated for cytotoxicity in the National Cancer Institute developmental therapeutics program. The tricyclic compound 7 was synthesized by the cyclization of 3,4-diamino-1,2dimethoxybenzene with diethyl 1,3-acetonedicarboxylate. Oxidation of monochloropyrido[4,3,2-de]quinoline 8 selectively produced 2,3-diketopyrido[4,3,2-de]quinoline 9 as deep violet crystals. Compound 9, when treated with acetone or acetophenone, affords the tetracyclic isoquinolino[6,5,4,3-cde]quinolines 13 and 14, respectively. 2,3-Diketopyrido[4,3,2-de]quinolines 9 and 10 exhibit higher cytotoxic potency than isoquinolino[6,5,4,3-cdelquinolines 13, 14, 15 and 16. Compound 9 selectively affects the cell growth against leukemia CCRF-CEM and HL-60 cell lines, the non-small cell lung cancer HOP-92 cell line, and breast cancer MDA-MB231/ ATCC and MDA-MB- 435 cell lines with GI(50) values of <2.0 microM. Modification of compound 9 with an ester group at the N-1 position afforded compound 10, which exhibits a wide spectrum of anticancer activities with a mean graph midpoint value of 1.8 microM against the 60 cancer cell lines.

Antineoplastic Agents↗
PubMedDate not supplied

Synthesis of the O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine oximes of selected carbonyl compounds and their determination by liquid chromatography with ultraviolet detection.

The aims were to develop a liquid chromatographic (LC) method with ultraviolet detection (UVD) for O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) O-oximes of common aldehydes and ketones, and to define the steric limits of the synthetic reaction used to make the PFBHA O-oxime standards for gas chromatographic (GC) and LC methods. Ten new O-oximes were synthesized with the new optimized method, and their purities were demonstrated by GC/electron-capture detection (ECD), GC/mass spectrometry (MS), ultraviolet spectroscopy, infrared spectroscopy, and proton and 13C-nuclear magnetic resonance spectroscopy. Ketones substituted at both beta-carbons relative to the carbonyl carbon, like diisobutyl ketone and 2,4-hexanedione, showed lower synthetic yields by wet chemistry methods. A new C18 reverse-phase LC method with UVD at 200 nm and acetonitrile-water in both the isocratic and gradient-elution modes was then developed to sensitively resolve a mixture of 13 pure PFBHA O-oximes. The detection limit was near 100 ng O-oxime/mL or about 14-50 ng aldehyde/mL and the least quantifiable limits were near 500 ng/mL or about 70-250 ng aldehyde/mL, with lower limits for glyoxal, methylglyoxal, benzaldehyde, and acetophenone. Carbonyl compounds in 500 mL water samples were then determined in distilled water and tap water by gradient elution. Vapors of n-valeraldehyde and acrolein generated in gas bags at concentrations near occupational guidelines were also sampled, desorbed, and then determined by either isocratic or gradient elution at 200 or 254 nm within 30-45 min.

Chromatography, Liquid↗
PubMed2001

Synthesis and evaluation of asperlicin analogues as non-peptidal cholecystokinin-antagonists.

The SAR of Asperlicin analogues is reported, leading to bioactive 1,4-benzodiazepine-2-ones, which were prepared in a 3 step reaction sequence. The Asperlicin substructure was built up using Tryptophan and readily available 2-amino-acetophenones. This template, containing a 1,4-benzodiazepin-2-one moiety with a 3-indolmethyl side chain, was transformed into mono- and di-substituted 3-indol-3'-yl-methyl-1,4-benzodi-azepine-2-ones by selective alkylation and acylation reactions. The SAR optimization of the 1,4-benzodiazepine scaffold has included variations at the 5-, 7-, 8-position, at the N1, N-indole nitrogen and the configuration of the C3-position. The most active Asperlicin analogue, having an IC50 of 1.6 microM on the CCKA receptor subtype, was obtained from Tryptophan in only 3 steps in an overall yield of 48%.

Animals↗
PubMed2001

SPME/GC-MS characterization of volatiles associated with methamphetamine: toward the development of a pseudomethamphetamine training material.

The headspace profiles of eleven methamphetamine (MA) samples have been analyzed using solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS). Nine of the eleven are illicit MA seizures from the Southwest U.S. border. One sample is methamphetamine base synthesized in the Drug Enforcement Administration (DEA) Southwest Laboratory, and the remaining sample is pharmaceutical-grade methamphetamine hydrochloride that is used to make training aids for drug detecting canines. In addition. volatiles associated with 1-phenyl-2-propanone (P2P), a methamphetamine precursor, have been identified for comparison with those found in methamphetamine seizure and the two reference samples. Eighty-seven different compounds were identified from all the samples, not including simple hydrocarbons and aldehydes. Only seven occur consistently in all seizure samples, and these are: acetic acid, benzaldehyde, acetophenone, P2P, 1-phenyl-1,2-propanedione (P12P), 3-phenyl-3-buten-2-one, 1-chloro-1-phenyl-2-propanone. Dimethyl sulfone, a common cutting agent in methamphetamine. was found in six of the nine seizure materials. When the reference methamphetamine and P2P samples are included, only two compounds are common to all twelve samples, and these are benzaldehyde and P2P. As such, these two compounds are likely candidates for use in a pseudomethamphetamine (PM) formulation, and their effectiveness in eliciting a canine response is being evaluated before actual deployment.

Animals↗
PubMedDate not supplied

Synthesis and reactions of some new substituted 6-imidazolyl-4-oxo-4H-1-benzopyran-3-carboxaldehyde and use of DNA in evaluation of their biological activity.

Vilsmeier-Haack reaction of imidazolyl acetophenone I gave 6-imidazolyl-4-oxo-4H-1-benzopyran-3-carboxaldehyde II. The compound II was reacted with primary amines (1:1 molar ratio) to form the corresponding n-aril (meteroaryl) imino derivatives IIIa-f. Treatment of aldehyde II with excess amines (1:2 molar ratio) gave the corresponding 2-arylamino-3-arylaminomethylenebenzopyran derivatives IVa-c. The n-aril (meteroaryl) imino derivatives IIIb,d,e,f were reacted with thioglycollic acid to give benzopyranothiazepinone derivatives VIa-d. When the aldehyde II was treated with secondary amines gave the corresponding trans-enaminoketones VIIIa-c. Trans-enaminoketones VIIIa-c were reacted with hydrazines and/or hydroxylamine hydrochloride to give pyrazolyl and/or isoxazolyl benzene IXa-c and X, respectively. The reaction of aldehyde II with hydrazines on cold gave the corresponding hydrazones XIIIa-d. However, the reaction of aldehyde II with hydrazines on refluxing gave the corresponding pyrazole derivatives 5 XIVa,b and XVa,b.. The structural formula of the new compounds were established by using different instrumental analyses. Some compounds in this study were biologically evaluated for their ability to bind to DNA.

Benzopyrans↗
PubMedDate not supplied

Recombinant human interleukin (IL)-1 beta-mediated regulation of hypoxia-inducible factor-1 alpha (HIF-1 alpha) stabilization, nuclear translocation and activation requires an antioxidant/reactive oxygen species (ROS)-sensitive mechanism.

Cytokine-mediated regulation of hypoxia-inducible factor-1 alpha (HIF-1 alpha) non-hypoxic stabilization, translocation and activation is not well characterized. Furthermore, evidence that reactive oxygen species (ROS) signaling mediates interleukin (IL)-1 beta-dependent regulation of HIF-1 alpha has yet to be ascertained in alveolar epithelial cells. Recombinant human IL-1 beta induced, in a time-dependent manner, the nuclear translocation of HIF-1 alpha, an effect associated with up-regulating the activity of this transcription factor under normoxic conditions. In addition, analysis of the mode of action of IL-1 beta revealed a novel induction of intracellular ROS, including hydrogen peroxide (H(2)O(2)), the superoxide anion (O(2)(-*)) and the hydroxyl radical (*OH). The antioxidants, dimethyl sulfoxide (DMSO) and 1,3-dimethyl-2-thiourea (DMTU), purported to be prototypical scavengers of H2O2 and *OH, attenuated, in a dose-dependent manner, IL-1 beta-induced HIF-1 alpha nuclear translocation and activation. The NADPH-oxidase inhibitor, 4'-hydroxy-3'-methoxy-acetophenone (HMAP), which may affect mitochondrial ROS production, attenuated IL-1 beta-mediated nuclear translocation and activation of HIF-1 alpha. Inhibition of the mitochondrion complex I nicotinamide adenine dinucleotide phosphate-dependent oxidase by diphenylene iodonium (DPI), which blocks the conversion of ubiquinone --> ubiquinol, abrogated IL-1 beta-dependent nuclear translocation and activation of HIF-1 alpha. Similarly, interrupting the respiratory chain with potassium cyanide reversed the excitatory effect of IL-1 beta on HIF-1 alpha nuclear translocation and activation. These results indicate that a non-hypoxic pathway mediates cytokine-dependent regulation of HIF-1 alpha translocation and activation in a ROS-sensitive mechanism.

Active Transport, Cell Nucleus↗