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PubMed1998

Identification of genes differentially expressed in Mycobacterium tuberculosis by differential display PCR.

RNA arbitrarily-primed differential display PCR (RAP-PCR) was used to identify and isolate genes differentially expressed between attenuated (H37Ra) and virulent (H37Rv, Erdman) laboratory strains of Mycobacterium tuberculosis (Mtb). Using this method, cDNA fragments showing homology to three known mycobacterial genes and six putative novel genes in mycobacterial cosmid vectors were identified. Among the putative novel Mtb genes identified, we found: (1) gene MTV041.29, containing multiple tandem repetitive sequences and encoding a putative Gly-, Ala, Asn-rich protein (PPE family); (2) gene MTV004.03, containing the AT10S repetitive gene sequence; (3) gene MTV028.09, encoding a hypothetical protein of unknown function; (4) genes MTCY78.20,21, possibly encoding two hypothetical proteins of unknown function; (5) gene MTCY01A6.09, encoding a putative novel ferrodoxin dependent glutamate synthase; and (6) gene MTCY31.20, encoding a putative cyclohexanone monooxygenase. Using gene specific primers in a second differential display PCR and by RT-PCR amplification, novel genes 1, 2, 3 and 4 were shown to be differentially up-regulated in the attenuated Mtb strain H37Ra compared to H37Rv and Erdman strain. Overall, we demonstrated that RAP-PCR, as a first step, is a quick and sensitive method for the identification and isolation of novel genes expressed in Mtb. Because of limitations inherent to the lack of specificity of arbitrary primers in the RAP-PCR method, a second differential display PCR and RT-PCR amplification with gene-specific primers was necessary in order to confirm differential expression of the identified genes.

Cloning, Molecular↗

PubMed1994

Exposure monitoring and health effect studies of workers occupationally exposed to cyclohexane vapor.

A survey was conducted in the second half of a working week on 33 women who either applied glue (with cyclohexane as an almost exclusive solvent component) or worked in the vicinity of glue application. Carbon cloth-equipped diffusive samplers were used for personal measurement of time-weighted average intensity of exposure to the solvent. The geometric mean and the highest cyclohexane concentration observed in air were 27 ppm and 274 ppm, respectively. Concentrations of cyclohexanol in urine samples and cyclohexane in whole blood and serum collected at the end of a shift showed significant correlations with the solvent exposure levels. Urinary cyclohexanone also correlated, but with a smaller correlation coefficient. The observation suggests that cyclohexanol in urine and cyclohexane in blood or serum collected at the end of a shift are useful indicators of occupational exposure to cyclohexane vapor. Quantitative estimation of balance at the end of the shift suggested that only a minute portion (< 1%) of cyclohexane absorbed is excreted in the urine as cyclohexanol, almost exclusively as a glucuronide. A survey of subjective symptoms revealed an increase in the prevalence of "dimmed vision " and "unusual smell", but hematology and serum biochemistry testing did not indicate any specific signs.

Adult↗

PubMed1983

Drosophila melanogaster alcohol dehydrogenase: an electrophoretic study of the AdhS, AdhF, and AdhUF alleloenzymes.

The nature and the interconversion of the three multiple forms Adh-5, Adh-4, and Adh-3 of the purified alleloenzymes AdhS, AdhF, and AdhUF from the fruitfly Drosophila melanogaster have been examined. The experiments show that these multiple forms differ from those in crude extracts of flies homozygous at the Adh locus. On electrophoresis in a starch gel containing NAD or NADH, of purified AdhS which consists of the three Adh forms S-5, S-4, and S-3, five enzymatically active zones appear. This contrasts with the single active zone that arises with crude extracts. Of the five zones that appear with purified enzyme, S-5 gives rise to one, while the other four zones come from the two minor forms S-4 and S-3. The occurrence of the three multiple forms Adh-5, Adh-4, and Adh-3 for each of the purified alleloenzymes is considered due to Adh-5 and, in the case of Adh-4 and Adh-3, deamidation of Adh-5, with the Adh-3 fraction also containing some reversible modified Adh-5. Of the labile amides, at least one must be located in the coenzyme binding region with deamidation preventing coenzyme binding. Pure NAD does not convert Adh-5 to Adh-3 and Adh-1. To produce conversion, the presence of either acetone or butanone along with NAD is necessary. Increased amounts of either acetone or butanone result in increased conversion. In contrast to this, none of the carbonyl compounds cyclohexanone, (+)-and (-)-verbenone, acetaldehyde, acrolein, or crotonaldehyde produces conversion. The ketone group binds to the alcohol binding site in the enzyme-NAD complex. Conversion is considered due to the ketone group binding to a nucleophilic amino acid residue and forming a bridge to the C-4 of the nicotinamide moiety of NAD.

Alcohol Dehydrogenase↗

PubMed2000

Synthesis and characterization of stereospecific 1-propargyl-2-(dimethoxymethyl)-1-cyclohexanols.

Stereochemical isomers with hydroxy groups were synthesized by reacting 2-(dimethoxymethyl)cyclohexanone with propargylmagnesium bromide. The stereo chemical structures were identified by NMR spectral interpretation and the geometry optimization. To assist the NMR interpretation, geometry optimization based on semi-empirical AM1 and PM3 methods was applied. Throughout this study, the structures of the two isomers were all determined and 1H and 13C NMR spectra were fully assigned. It was proven that the less polar isomer is an axial alcohol and the more polar one is an equatorial alcohol.

Alkynes↗

PubMed2000

Synthesis and biological activity of conformationally controlled 2-PAM derivatives.

A series of conformationally controlled 2-PAM derivatives were prepared from 2-acetylpyridine and 2,3-pyrido[b]cycloalkenones in two steps and their reactivities towards parathion poisoned AChE were evaluated. The most planar 2,3-pyrido[b]cyclohexanone oxime methiodide showed an activity comparable to 2-PAM implying E-syn is that the most active conformation of 2-PAM in the biological system.

Acetylcholinesterase↗

PubMed1984

Colorimetric estimation of inorganic phosphate in colored and/or turbid biological samples: assay of phosphohydrolases.

A simple method of inorganic phosphate determination for colored and/or turbid biological samples is described. The procedure is mild, and so is suitable for routine phosphohydrolase assays. Following deproteinization by ice-cold trichloroacetic (or silicotungstic) acid, the sample was treated with acid-washed charcoal to remove interference due to color. The phosphate in the colorless supernatant was assayed either by measuring the phosphomolybdate spectrophotometrically at 310 nm, following its extraction in organic solvents or by a modified Fiske and Subbarow method. The turbidity interference in the latter case was eliminated either by centrifugation, by sodium dodecyl sulfate treatment, or by extraction of reduced phosphomolybdate blue color by cyclohexanone. Though deproteinization by silicotungstic acid eliminated the turbidity problem, its use in conjunction with charcoal treatment was not convenient.

Animals↗

PubMed1990

Analysis of aldehydic lipid peroxidation products in rat liver and hepatocytes by gas chromatography and mass spectrometry of the oxime-tert-butyldimethylsilyl derivatives.

A method for analysis of aliphatic aldehydes in biological samples is described. Cyclohexanone is added as internal standard and the samples are treated with hydroxylamine and perchloric acid. The oximes are extracted and converted to the oxime-tert-butyldimethylsilyl derivatives, which are quantitated by capillary gas chromatography and identified by mass spectrometry. The characteristic M-57 fragment ions in the mass spectra enabled a rapid identification of the derivatives of the aldehydes, alkanals, alk-2-enals, alka-2,4-dienals, and 4-hydroxyalk-2-enals, which in addition gave rise to characteristic double peaks in the gas chromatographic analysis. The method was applied to analysis of autoxidized arachidonic acid, ADP-Fe3(+)-treated rat hepatocytes, and rat liver given a single dose of ethanol, 5 g/kg. The amounts of hexanal and 4-hydroxynon-2-enal were not increased 6 h after the administration of ethanol.

Adenosine Diphosphate↗

PubMed1993

Ethanol metabolism in isolated hepatocytes. Effects of methylene blue, cyanamide and penicillamine on the redox state of the bound coenzyme and on the substrate exchange at alcohol dehydrogenase.

Ethanol metabolism in hepatocytes increases the NADH/NAD+ ratio. The mechanism was investigated by measurements of the redox state of the coenzyme bound to alcohol dehydrogenase and of ethanol-acetaldehyde exchange and concomitant hydrogen transfer between ethanol molecules. Isolated hepatocytes from fed rats were incubated with cyclohexanone and cyclohexanol or with [1,1-2H2]-and [2,2,2-2H3]ethanol, followed by gas chromatographic determination of the redox state and isotope analysis of the ethanol by gas chromatography-mass spectrometry, respectively. Cyanamide and methylene blue decreased the redox shift caused by ethanol and increased the rates of acetaldehyde reduction during the exchange. Both drugs increased the extent of hydrogen transfer between ethanol molecules during oxidoreduction. Penicillamine had no significant effect on the ethanol-induced change in redox state of the bound coenzyme although it decreased the rate of acetaldehyde reduction. The results indicate that methylene blue inhibits aldehyde dehydrogenase and that accumulation of acetaldehyde decreases the redox effects of ethanol. The redox effect appears to result primarily from rapid elimination of acetaldehyde and equilibration with the NAD system on the alcohol dehydrogenase, but is not enhanced by further decreases in acetaldehyde concentration. Thus, penicillamine could probably be used to decrease the concentration of acetaldehyde without increasing the redox effects.

Acetaldehyde↗

PubMed1984

Receptor cell responses to odorants: similarities and differences among odorants.

An extensive exploration of the discriminating properties of olfactory receptors cells has been conducted in our laboratory through the statistical processing of single cell responses recorded in the frog's olfactory epithelium. Similarities between odorant stimulating properties could be demonstrated by comparing the complex response profiles of receptor cells, resulting in the concept of odorant groups which depicts consistent relationships found between some odorous compounds. The recording technique limits the number of odorants which can be tested and compared within the same series of experiments. Thus, based upon previous studies we have chosen a specific set of 20 odorants whose characteristics are known but, up to this time, have not been compared in the same experimental system. These odorants were: acetophenone, anisole, n-butanol, DL-camphor, cyclodecanone, 1,8-cineole, p-cymene, D-citronellol, n-heptanol, isoamyl acetate, isovaleric acid, D-limonene, methyl amylketone, L-menthol, phenol, thiophenol, pyridine, thymol, cyclohexanol, cyclohexanone. The pattern of similarities between these odorants, as delineated with the aid of correlation coefficient computation, factor analysis and non-hierarchical taxonomy, confirms the reality of several odorant groups previously suggested and describes their cross-relationships. The receptor mechanisms underlying these odorant groups are discussed. Because reliable prominent features of the olfactory stimulus space can be established on an objective basis, the findings are proposed as a reference for future studies on other aspects of olfactory discrimination.

Animals↗

PubMed1985

Olfactory discrimination of structurally related molecules: receptor cell responses to camphoraceous odorants.

Electrophysiological investigations of the selective sensitivity of receptor cells have shown that odorants could be distributed into groups according to the profiles of responses that they elicited from a population of receptor cells. As the concept of odorant group plays an important role in the understanding of olfactory coding, an attempt was made to investigate in detail the group properties of a number of structurally and qualitatively related molecules: 1,8 cineole, DL-camphor, borneol, iso-borneol, adamantane, fenchone, fenchyl alcohol, 3,3,5-tri-methyl cyclohexanone, camphene, 1,1,2,2-tetra-bromoethane. These odorants, along with several other representatives of other odorant groups, were utilized to stimulate a set of 71 individually recorded receptor cells. Factor analysis of electrophysiological data demonstrated that the grouping of odorants with camphor could be predicted on the basis of the shape and size of the molecules. The analysis also showed that even a clearly defined odorant group such as the camphor group is not likely to be determined by a single type of receptor site.

Animals↗

PubMed1987

The binding of an aminoazo dye carcinogen to a specific methionine residue in rat liver alcohol dehydrogenase in vivo.

On the administration of 3'-methyl-N,N-dimethyl-4-aminoazobenzene to rats pure aminoazo dye-bound alcohol dehydrogenase accounting for 45% of the total soluble protein bound aminoazo dye is isolated from the liver soluble supernatant. Tryptic digestion of that purified aminoazo dye-bound enzyme yields an aminoazo dye-bound nonapeptide which has a sequence identical to amino acids 301-309 in the known sequence of alcohol dehydrogenase (H. Jornvall and O. Markovic, Eur. J. Biochem., 29 (1972) 167-174) with the exception of methionine 306 which is replaced by an aminoazo dye modified amino acid. The nature of the aminoazo dye adduct was determined by studying the structure of the related tetrapeptide obtained by Pronase B digestion and shown by proton NMR spectroscopy and fast atom bombardment mass spectroscopy to have the structure 3-(Val. Asn. Pro. Homocystein-S-yl)-4-methylamino-3'-methylazobenzene. This carcinogen-protein adduct is assumed to arise from attack of the ultimate carcinogenic metabolite, N-sulphonyloxy-4-methylamino-3'-methylazobenzene (FF. Kadlubar, J.A. Miller and E.C. Miller, Cancer Res., 36 (1976) 2350-2359) at the sulphur of methionine 306 followed by spontaneous S-demethylation. This highly specific reaction of carcinogen with alcohol dehydrogenase lowers its Vmax and increases its Km with cyclohexanone thereby reducing its catalytic efficiency for this substrate. This highly specific reaction of the carcinogen with alcohol dehydrogenase may be regarded as a major detoxication reaction.

Alcohol Dehydrogenase↗

PubMed1976

A study of muscarinic receptor heterogeneity with weak antagonists.

A study of heterogeneity among muscarinic receptors was carried out with new rigid molecules, comprising structures in the fused quinuclidine-valerolactone, quinuclidine-cyclohexenone, quinuclidine-cyclohexanone and quinuclidine-cyclohexane derivatives. These are structurally related to the potent muscarinic agent, 3-acetoxyquinuclidine but substantially different from in it conformation. All proved to antagonize acetylcholine-like activity, but to a different extent in different systems. The equipotent molar ratio with respect to atropine (as 1) was: isolated guinea pig ileum, 10,000-1,000; salivary gland (mouse), 1,000-100; superior cervical ganglion (cat), 100-10; CNS (mouse), approximately 10. It is suggested that the rigid structure induces a three-point constrained fit in the receptor (onium group, hydrophobic moiety and carbonyl group), but that not all muscarinic receptors are capable of responding equally. In this case, receptor specificity of the drug is a direct consequence of its graded departure from the preferred conformation of acetycholine and, therefore, is necessarily associated with partial loss of potency.

Animals↗

PubMed1996

Mechanisms of epidermal growth factor-induced contraction of guinea pig airways.

We investigated the functional effects of epidermal growth factor (EGF) on guinea pig airways in vitro. EGF (3 ng/ml to 1 microgram/ml) induced a concentration-dependent contraction in epithelium-denuded strips. The average maximal contraction was 0.64 +/- 0.1 g (mean +/- S.E., for n = 27), which was 72.0 +/- 9.5% of the 100 mM KCl-induced contraction. The EC50 was 12.3 +/- 1.6 ng/ml. The presence of the epithelium significantly suppressed the EGF-induced contraction (P < 0.01). EGF-induced contraction was abolished by cyclooxygenase inhibitors (indomethacin and ibuprofen) and a 5-lipoxygenase inhibitor, 2-(12-hydroxydodeca-5,10-diynyl)-3,5,6-trimethyl-1,4-benz oqu inone (AA-861). It was also inhibited by a leukotriene-receptor antagonist, 8-[p-(4-phenylbutyloxy)benzoyl]amino-2-(tetrazol-5-yl)-4-oxo -4H-1-benzopyran hemihydrate (ONO-1078) but not affected by a thromboxane A2-synthetase inhibitor, (E)-3-[4-(1-imidazolylmethyl)phenyl]-2-propenoic acid (OKY-046) or a thromboxane A2-receptor antagonist, 9,11-epithio-11,12-methano-thromboxane A2 (ONO-3708). A phospholipase A2 inhibitor (mepacrine) inhibited the EGF-induced contraction but a diacylglycerol-lipase inhibitor, 1,6-di-(O-(carbamoyl)cyclohexanone oxime)hexane (U-57908) and a phospholipase D inhibitor (wortmannin) did not affect it. A tyrosine kinase inhibitor (genistein) abolished it. Measurement of prostanoids showed that EGF (300 ng/ml) did not increase the prostaglandin F2 alpha level in either epithelium-intact or epithelium-denuded strips. In epithelium-intact strips, EGF significantly increased the prostaglandin E2 concentration (P < 0.01). These results suggest that EGF causes contraction of guinea pig airway smooth muscle by activating tyrosine kinase followed by phospholipase A2 activation, and that arachidonic acid metabolites, especially leukotrienes, may have important roles in this contraction.

Animals↗

PubMed1984

A new approach for using cofactor dependent enzymes: example of alcohol dehydrogenase.

The use of enzymes requiring a cofactor as substrate in organic synthesis is still a problem since the cofactors are expensive. This study deals with a new approach consisting of using fragments of NAD+. Three fragments of NAD(H) are examined. The activities of NMN+ and NMNH are greatly improved by the addition of adenosine in ethanol oxidation and in cyclohexanone reduction, respectively. Nicotinamide mononucleoside is not active in the ethanol oxidation but the addition of AMP promotes this reaction.

Adenosine↗

PubMed1987

Decrease in oligodendrocyte carbonic anhydrase activity preceding myelin degeneration in cuprizone induced demyelination.

Both immunohistochemical and biochemical evidence is presented to show for the first time that carbonic anhydrase II (CA II) activity falls in the brain of mice in cuprizone (bis(cyclohexanone)oxalyldihydrazone) induced demyelination well before demyelination develops. This fall began during the first week, whereas the first signs of myelin degeneration induced by cuprizone did not appear until 3 weeks and demyelination in the superior cerebellar peduncle in the mouse took 6-8 weeks to develop. The findings suggest that oligodendrocyte CA II activity is essential either for the survival of oligodendrocytes or for the maintenance of central myelin.

Animals↗

PubMed1990

Hyperthermic and anorectic effects of oxazolidines derived from L-ephedrine in rats.

Oxazolidines synthesized from (-) ephedrine have been proposed as potential pro-drugs, but no pharmacological data on these compounds has been yet reported. In this study, four such compounds are tested in rats for ephedrine-like activity using the hyperthermia and anorexia models. The compounds were synthesized by reaction of (-) ephedrine with salicylaldehyde, acetone, cyclohexanone, and benzaldehyde, respectively. The results showed that all of the compounds decreased food intake significantly, but only the acetone and the salicylaldehyde derivatives caused a significant elevation of body temperature. All of the compounds were less effective than (-) ephedrine in the anorexia model. The acetone and salicylaldehyde derivatives showed similar potency to (-) ephedrine in the hyperthermia model.

Animals↗

PubMed1982

Effect of odor quality and intensity on conditioned odor aversion learning in the rat.

Odor quality and intensity were varied to test the ability of rats to associate odor with an induced illness. Rats were allowed 10 minutes access to water on each of nine days; deodorized air was directed towards each rat's nose while drinking at familiarization and recovery sessions (days 1-5 and 7-8, respectively) and odorized air at treatment and test sessions (days 6 and 9, respectively). Each rat was injected with LiCl following its drinking period on day 6. The difference between the amount of water consumed on day 6 and day 9 gave a measure of the conditioned aversion. Only mild or no aversion occurred with odors of n-butyric acid, benzylamine, cyclohexanone, and n-butanol. Strong conditioned aversions were obtained to odors of triethylamine, 1,4-cineole, and isoamyl acetate, and the degree of aversion increased linearly with the log of odor concentration. The effect of odor quality, intensity and presentation method, and the role of the different chemoreceptor systems in the acquisition of odor aversions are discussed.

Animals↗

PubMed1990

Rat fetuses respond to chemical stimuli in gas phase.

Fetuses exhibit behavioral responses to intraoral infusions of chemical solutions presented in liquid phase, including an increase in overall activity and the production of a species-typical action pattern, facial wiping. A series of experiments were conducted in which chemical compounds with strong olfactory characteristics--citral and cyclohexanone--were presented in gas phase to rat fetuses on day 20 of gestation. Fetuses exhibited similar behavioral responses to stimuli presented in liquid and gas phases, suggesting a common basis for the processing of prenatal chemosensory information. Chemosensory stimuli in gas phase are sufficient to elicit both behavioral activation and a stereotypic action pattern of the rat fetus, patterns that anticipate postnatal olfactory-directed behavior. These results suggest that prenatal chemosensory experience, which normally occurs in an aqueous medium, may be relevant to the development of postnatal behavior that is directed by airborne olfactory cues.

Animals↗