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  • Articles  (94)
  • Column liquid chromatography  (54)
  • Coleoptera  (39)
  • Chemistry
  • Springer  (94)
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  • 1987  (94)
  • Chemistry and Pharmacology  (94)
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  • Articles  (94)
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  • 1985-1989  (94)
  • 1960-1964
  • 1950-1954
  • 1945-1949
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  • Chemistry and Pharmacology  (94)
  • Political Science
  • Process Engineering, Biotechnology, Nutrition Technology
  • Biology  (47)
  • Medicine  (2)
  • 1
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    Springer
    Journal of chemical ecology 13 (1987), S. 219-226 
    ISSN: 1573-1561
    Keywords: Ablation ; egg dispersion ; oviposition deterrent ; foretarsi ; palpi ; antennae ; Coleoptera ; Bruchidae ; Callosobruchus maculatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Females ofCallosobruchus maculatus (F.) avoid ovipositing on host seeds already bearing conspecific eggs, and thus distribute eggs evenly among seeds. This behavior was presumed to be mediated by an ether-soluble “oviposition marker” that is deposited with the egg and can be extracted from egg-laden artificial hosts (glass beads). Ablation experiments revealed that the true factors promoting an even dispersion of eggs were perceived by the maxillary and labial palpi. In contrast, receptors on the antennae were largely responsible for avoidance of seeds treated with “oviposition marker.” Taken together, these results suggest that a careful distinction should be drawn between factors that promote spacing of eggs under natural conditions and general oviposition deterrents that may be isolated from both sexes.
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  • 2
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    Journal of chemical ecology 13 (1987), S. 2009-2022 
    ISSN: 1573-1561
    Keywords: Leptinotarsa decemlineata ; Coleoptera ; Chrysomelidae ; Colorado potato beetle ; deterrent receptor ; feeding deterrents ; alkaloids ; sugar receptor ; amino acid receptor ; chemoreception ; steroidal alkaloids ; antifeedants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The galeal chemosensory system of the adult Colorado potato beetle was used as a model to study the effects of alkaloids on insect gustation. Nine alkaloids, representing a wide range of structural types, were used. Their ability to stimulate chemosensory cells when presented in isolation and their ability to interfere with normal chemosensory processes were emphasized. None of the alkaloids stimulated chemosensory cells in a dose-dependent manner, although a few stimulated low-level activity from some cells. There was no evidence for a general “deterrent receptor” in these beetles. Some of the alkaloids had a marked inhibitory effect on normal chemosensory responses. Tomatine, solanine, papaverine, and sparteine significantly inhibited responses to amino acids (represented by GABA) while quinine and papaverine inhibited responses to sucrose. An attempt was made to correlate neurophysiological action of some alkaloids with their effects on feeding behavior. It was clear from this correlation that even a dramatic inhibition of sensory input by an alkaloid does not necessarily lead to measurable effects on behavior. The results are discussed in the context of current theories on the mode of action of alkaloids and other secondary plant compounds which may be involved in host recognition by phytophagous insects.
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  • 3
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    Journal of chemical ecology 13 (1987), S. 35-38 
    ISSN: 1573-1561
    Keywords: Coleoptera ; Silphidae ; Silpha novaboracensis ; steroids ; pregnanes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Two novel steroids, 3α,7β-dihydroxy-14β-pregn-4-en-15,20-dione (1) and 3α,7β, 20ξ-trihydroxy-14β-pregn-4-en-15-one (4), have been characterized from the rectal gland ofSilpha novaboracensis (Coleoptera: Silphidae). Judging from the function of comparable pregnanes in another species ofSilpha, the compounds may play an antipredator role.
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  • 4
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    Journal of chemical ecology 13 (1987), S. 39-46 
    ISSN: 1573-1561
    Keywords: Solanum ; glycoalkaloid ; Leptinotarsa decemlineata ; protein ; growth ; Coleoptera ; Chrysomelidae ; α-tomatine ; α-solamarine ; β-solamarine ; α-solamine ; α-chacomine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Growth of larvae of the Colorado potato beetle,Leptinotarsa decemlineata (Say), as measured by weight gain, was determined when larvae were reared on synthetic diets containing measured quantities of protein and one of fiveSolanum glycoalkaloids. Data were analyzed to determine if growth was affected by these two aspects of phytochemical variation independently, or if there was a significant interaction component in larval weight gain to simultaneous variation in protein and glycoalkaloid concentration. For four of the five glycoalkaloids examined, a bivariate regression model without interaction accurately accounted for growth ofL. decemlineata larvae. For alpha-tomatine, however, a regression model with the addition of a (protein × glycoalkaloid) interaction term more accurately accounted for larval growth. The influence of this interaction was less than either protein or glycoalkaloid concentration alone. The variation in protein concentration accounted for most of the variation in larval growth, and high protein concentrations could more than offset the effect of high concentration of any of the five glycoalkaloids.
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  • 5
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    Journal of chemical ecology 13 (1987), S. 335-344 
    ISSN: 1573-1561
    Keywords: Kairomone ; parasite ; host finding ; host acceptance ; behavior ; Edovum puttleri ; Hymenoptera ; Eulophidae ; Colorado potato beetle ; Leptinotarsa decemlineata ; Coleoptera ; Chrysomelidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract When females of the eulophid parasiteEdovum puttleri were exposed to ann-hexane wash of eggs of the Colorado potato beetle,Leptinotarsa decemlineata, their responses indicated that the eggs contained a kairomone which elicited host-finding and host-acceptance behaviors. The hostfinding responses included an increased amount of time searching glass beads treated with kairomone, and drumming on the beads with the flagellum of the antennae. Host-acceptance responses included grasping of the beads with the legs, raising of the abdomen, and probing the kairomone-treated surface with the ovipositor. None of these responses were noted in females on beads treated only with hexane, or in males exposed to kairomone-treated beads. When kairomone was applied to a flat surface, filter paper disks, few episodes of drumming and no episodes of probing with the ovipositor were noted. Responses ofE.puttleri to eggs of Colorado potato beetle were similar to those on kairomone-treated beads, but females normally drilled into eggs and fed on host fluids after retracting the ovipositor. The kairomone is volatile, and responsiveness was reduced in parasites exposed to beads treated several hours previously.
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  • 6
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    Journal of chemical ecology 13 (1987), S. 2143-2157 
    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Coleoptera ; Scolytidae ; pheromone ; synergism ; plumes ; exo-brevicomin ; frontalin ; myrcene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The relationships between catch ofD. brevicomis LeC. at sources of the synergistic pheromone components,exo-brevicomin (E) and frontalin (F), and increasing distance of separation of sources were investigated in the forest. The two components were each released with the host monoterpene, myrcene (M), in trap pairs. The traps of each pair were spaced apart at various distances (0–16 m) in either horizontal or vertical lines that were perpendicular to the mean wind direction. Both sexes were most strongly attracted when the two components were released from the same source, and increasing distance of separation between components caused exponential decreases in trap catch for all trap configurations. Males were significantly more attracted to traps with E, M alone than to corresponding traps with F, M alone, while females exhibited a preference for F, M. The theoretical relationships and properties of two coalescing plumes of individual components and their intersecting “active space” are presented and discussed. It is proposed that “confusion” or “communication disruption” techniques for insect control may be more successful if components are released individually from many points rather than released similarly in blends.
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  • 7
    ISSN: 1573-1561
    Keywords: 2-Methyl-3-buten-2-ol ; cis-verbenol ; trans-verbenol ; myrtenol ; trans-myrtanol ; 2-phenylethanol ; ipsdienol ; subtractive assay ; Ips typographus ; Coleoptera ; Scolytidae ; Picea abies ; host volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Six compounds previously identified from hindguts of unmated maleIps typographus (L.) during host colonization: 2-methyl-3-buten-2-ol (MB),cis-verbenol (cV),trans-verbenol (tV), myrtenol (Mt),trans-myrtanol (tM), and 2-phenylethanol (PE), were tested for their attractivity in the field with a subtractive method. The amounts of MB and cV released from a pipe trap were similar to those given off from the commercial bait Ipslure as well as that from a Norway spruce tree,Picea abies (L.) Karst., under mass attack. The blend of the compounds became nonattractive when either MB or cV was subtracted, while subtraction of any of the other four compounds had no effect. Addition of ipsdienol (Id) to the blend did not significantly increase the attraction. In a second comparative test, the addition of three compounds as a group (tV + Mt + PE) to MB + cV again had no effect on the attraction, but the addition of Id increased the catch somewhat. Addition of host logs to a bait releasing MB + cV at a rate lower than in previous experiments did not influence the attraction to pipe traps. Sticky traps containing natural pheromone sources (50 males in a log), which released 1–5 mg/day of MB as determined by aerations with deuterated MB as internal standard, were less attractive than a synthetic source releasing similar amounts of MB.
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  • 8
    ISSN: 1573-1561
    Keywords: Diabrotica ; Coleoptera ; Chrysomelidae ; western com rootworm ; southern corn rootworm ; northern corn rootworm ; attractants ; semiochemicals ; veratrole ; estragole ; trans-anethole ; indole ; eugenol ; phenylacetaldehyde
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract During the summers of 1984 and 1985, a variety of structurally related benzenoid compounds was evaluated in sweet corn plots as attractants for adult southern corn rootworms (SCR), western com rootworms (WCR), and northern corn rootworms (NCR). Field response to the volatiles was measured by beetle counts on baited cylindrical sticky traps placed inside the corn plots at a height of l m above ground level. SCR adults were attracted late in the season (last week of August through September, 1984 and 1985) to numerous aromatic compounds, including phenylacetaldehyde, benzyl acetone, phenethyl alcohol, phenyl acetate, indole, veratrole, methyl eugenol, methyl isoeugenol, eugenol, and isoeugenol. Although many compounds attracted SCR adults late in the season, only veratrole, phenylacetaldehyde, and chavicol were significantly active in early and middle August 1985. WCR adults were attracted to a different group of compounds, namely estragole,trans-anethole, and indole. Estragole (4-methoxy-1-allylbenzene) was an effective WCR attractant from corn tasseling in early August 1985, until the end of the trapping period in late September and early October 1985. Indole andtrans-anethole (4-methoxy-1-propenylbenzene) were less effective attractants than estragole and were most active at the beginning and/or end of the corn season. Traps baited with 100 mg of estragole caught an average of 20 times more WCR adults than unbaited control traps, and the females outnumbered the males in the baited traps. Estragole dosage tests were conducted in three sweet corn plots on different dates in 1985 and the minimum effective dose ranged between 5 and 30 mg/trap. Field tests with structural analogs revealed the importance of the site of unsaturation in the allylic side chain of estragole and the effect of different ring substituents on WCR response. The phenylpropanoids, eugenol and isoeugenol, significantly attracted NCR adults, even though these beetles were in low abundance in the test corn plots. Field tests indicate there is no cross-species response by WCR and NCR adults to their related phenylpropanoid attractants. However, in late August, SCR adults do respond to some WCR and NCR attractants (indole and several eugenol analogs). Electroantennographic analysis of SCR males revealed they can perceive peripherally a wide range of benzenoid compounds.
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  • 9
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    Journal of chemical ecology 13 (1987), S. 1087-1097 
    ISSN: 1573-1561
    Keywords: Boll weevil ; Anthonomus grandis Boh. ; Coleoptera ; Curculionidae ; Rose-of-Sharon ; Hibiscus syriacus L. ; feeding deterrent ; unsaturated fatty acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The Rose-of-Sharon,Hibiscus syriacus (L.), can be a significant alternate host plant for the boll weevil,Anthonomus gradis (Boh.). Boll weevils are known to be deterred from feeding and ovipositing in the buds unless the calyx is removed. This investigation was initiated to identify calyx allelochemicals that deter feeding with the eventual strategy of breeding for cotton lines high in these allelochemicals in the appropriate tissues. The feeding deterrency of calyx tissue from the buds of Rose-of-Sharon for the boll weevil was confirmed. The most active deterrent fraction was found to contain mostly fatty acids and their methyl esters. Saturated fatty acids and their methyl esters were generally found to be stimulatory, while the unsaturated species were found to be deterrent. Higher quantities of the fatty acids, particularly the unsaturated species, were found in Rose-of-Sharon calyx tissue than in the buds without calyx. This supports the hypothesis developed through the isolational work and testing of standards that the unsaturated fatty acids are significant deterrents of boll weevil feeding.
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  • 10
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    Journal of chemical ecology 13 (1987), S. 1279-1292 
    ISSN: 1573-1561
    Keywords: Diabrotica sp ; kinetic resolution ; lipase ; methyl carbinol ; Mucor miehei ; pheromone ; western corn rootworm ; Coleoptera ; Chrysomelidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The relative rates of enzyme-catalyzed esterification of the enantiomers of 2-octanol with various acids were determined for several commercial lipases. Interesterifications and hydrolyses of racemic 2-octanol esters catalyzed by these enzymes were also examined. Novo'sMucor miehei lipase exhibited considerable enantioselectivity and was therefore employed to prepare 8-methyl-2-decanols with high configurational purity at the carbinol carbon. Esters of these alcohols had been previously identified as sexually attractive to several rootworm (Diabrotica) species, and the stereochemistry of those esters had been shown to be critical to the attraction. The enzymatic resolution provides a convenient method to obtain such esters in a desired state of configurational purity.
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  • 11
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    Chromatographia 23 (1987), S. 796-802 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Steroids ; Rat tissue ; Purification by extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A high-performance liquid chromatographic method for analysis of steroids in the tissue of laboratory animals is described. A two-stage solid extraction procedure, utilizing Sep-pak C18 and graphitized carbon black, gives a purified product. Steroids in this extract were separated by multistep gradient elution with a reversedphase liquid chromatography system, using acetonitrilewater as solvent. Several columns with different geometry and phase loading were investigated. Optimum resolution was obtained with a medium covered and spherical particle. The applicability of this method was successfully demonstrated in the analysis of the testis and adrenal gland of rat.
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  • 12
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    Chromatographia 23 (1987), S. 814-817 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thin layer chromatography ; Ammonium tungstophosphate ; Aminoacids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The chromatographic behaviour of aminoacids on columns of silica coated with different percentages of ammonium tungstophosphate at several buffer phosphate concentrations is reported. The stationary phase shows a high selectivity towards aminobutyric acids and methyl derivatives of tryptophan due to the distance between the carboxylic group and the −NH 3 + group involved in the cation-exchange process and/or to the steric hindrance by a methyl substituent. A relationship between HPLC and HPTLC data has been verified and applied to the prediction of the separation of six aminoacids.
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  • 13
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    Chromatographia 23 (1987), S. 934-938 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Calibration ; Confidence interval ; Limit of determination ; Limit of calibration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary In HPLC calibration the expressions lowest calibration limit and determination limit are defined in statistical terms. The lowest calibration limit is the minimum mass in the measured series of calibration points. It is calculated from the confidence interval of the inverse of the calibration function as the lowest mass limit that may be differentiated from zero mass with a preset probability of error. If the calculated lowest calibration limit is lower than the actual data, points at lower concentration may be measured. The determination limit is the smallest concentration of an analysis that is differentiated from the concentration zero or an apparent blind value in the calibration curve with a given probability of error. Using two different UV-detectors (variable wavelength and photodiode-array) the lowest calibration limit is experimentally evaluated and compared with specific data for the detectors.
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  • 14
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Pre-column derivatization ; Ultraviolet detector sensitivity ; Dihydroartemisinin ; Diacetyldihydrofluorescein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The use of diacetyldihydrofluorescein (DADF) for derivatization of dihydroartemisinin (dihydroqinghaosu, DHQHS) is proposed. The reaction between DHQHS and this reagent in the presence of 4-dimethylaminopyridine (DMAP) and N,N′-dicyclohexylcarbodiimide (DCC) was complete in 8 hours at room temperature giving about 80 per cent theoretical yield. The derivative showed intense UV absorption, thus providing a sensitivity of 0.1 nanogram by UV detection after column separation. The influences of the ratio of the reagents, reaction temperature, chromatographic conditions and the extent of detection linearity were investigated. The reaction gave consistent results and chromatographic separation was not affected by an excess of the reagent or side products.
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  • 15
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    Chromatographia 23 (1987), S. 395-400 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Photokinetic data ; Reaction mechanism ; (E)-1-phenylpropene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A combined method of high-performance liquid chromatography and UV-absorption spectroscopy is described for use in dynamic systems. It provides a way of obtaining detailed mechanistic information as well as quantitative data (rate constants, quantum yields), even though neither mechanism nor photoproducts are known. The kinetic treatment of the photoreaction of (E)-1-phenylpropene was successful, showing a photo-isomerization and a parallel step. Information on this additional step is obtained by using HPLC to observe the changes in the concentrations of the reactants' selectivity. The necessity of process control is demonstrated.
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  • 16
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    Chromatographia 23 (1987), S. 419-422 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Fatty acid esters ; Particulate material in seawater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method for the determination of fatty acids of the molecular weight range of propionic to erucic acid is reported. The acids are converted to either p-bromophenacyl-or p-phenylphenacylesters and the esters are separated by HPLC and detected by UV-absorption. Twentytwo esters, including saturated, monoolefinic and polyunsaturated ones were separated within one HPLC-run. The detection limit is about 5 pmol per fatty acid. The application of the method to particulate material is described.
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  • 17
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Anion-exchange stationary phases ; Polymer coating ; Cross-linking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary PHEB=POLY(2-hydroxy, 3N-ethylenediamino)butadiene has been synthesized. This unsaturated pre-polymer can be immobilized on different, preferably inorganic supports of suitable porosity such as silica or alumina by cross-linking. Weak anion-exchange phase are obtained. Such phases do not have the disadvantages of organic polymeric phases, regarding pressure stability and swelling by solvent influence. The ion-exchange capacity and the retentivity of IE-separations can deliberately be varied via the thickness of the cross-linked polymer layer. Alumina can also be coated with PHEB applying the same cross-linking procedure. Such phases exhibit an exceptional chemical stability even when operated with mobile phases at very high pH-values. Separations of excellent selectivity are achieved for inorganic anions, as well as with mixtures of aliphatic and aromatic free acids also including hydroxy- (mono- or poly)carboxylic acids.
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  • 18
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed-phase systems ; Stationary phase-solute interactions ; Polycyclic aromatics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Capacity factors of peropyrene-type polycyclic aromatic hydrocarbons were measured using 15 different liquid chromatographic reversed phase systems. On the basis of the retention data the electric interaction indices have been calculated. Application of these indices for structure-retention studies on peropyrene-type polycyclic aromatic hydrocarbons is demonstrated.
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  • 19
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    Chromatographia 23 (1987), S. 31-32 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gonadal steroids ; Epimers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Chromatographic separation of biologically active epimeric steroids was carried out using a combination of normal and reversed phases. Testosterone (17β-OH) was separated from its 17α-OH epimer epitestosterone using a normal phase silica column whereas their reduced 5α-metabolites were separated on a reversed phase system. The separation of other gonadal steroids including the epimers 20α- and 20β-hydroxypregn-4-en-3-one is also discussed. The technique is particularly useful for separating mixtures of naturally occurring steroid epimers prior to radioimmunoassay.
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  • 20
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ammonium acetate buffer eluent ; Chlorophylls and degradation products ; Marine phytoplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An RP-HPLC procedure which separates chlorophylls and their degradation products is described. By employing an amonium acetate buffered mobile phase and a linear gradient elution, complex mixtures of chloroand phaeopigments are separated in less than 30 minutes. The method has been applied to the control of chlorophyll enzymatic degradation in cultures of two algal species, and has also been successfully used in the analysis of algal xanthophylls.
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  • 21
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Behaviour of metal complexes ; Solvophobic theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The chromatographic behaviour of Cu(II), Fe(II), Ni(II) and Co(II) complexes with 4-(2-pyridylazo)resorcinol was studied. The experimental results were very sensitive even to less obvious operational parameters like the kind of the cation (sodium or ammonium) of the phosphate salt used as buffer. The puzzling pattern of the data obtained was interpreted in terms of the equations formulated by Horvath's ‘olvophobic” theory which correlates the capacity factors of the solutes with the surface tension of the mobile phase. A satisfactory rationalization of the data was obtained together with qualitative information on the stoichiometry and charge state of metal complexes. Useful suggestions about the direction to address the experimental work in order to obtain the best results was also obtained.
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  • 22
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ligand Exchange ; Diethylenetriaminepentaacetic acid ; Transition metal ion separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Basic alumina-bonded diethylenetriaminepentaacetic acid (DTPA) has been utilized for the separation and preconcentration of some transition metal ions on the basis of ligand exchange. Breakthrough capacity and rate of sorption have been studied. The distribution coefficients of 16 transition metal ions have been determined in demineralized water, 0.01 M sodium citrate and in four different pH systems. On the basis of differences in Kd values some quantitative separations of metal ions have been achieved. The greater selectivity behaviour (higher Kd values) of the adsorbent for Pt(IV)and Cr(III) has been utilized for their preconcentration in the presence of other metal ions. The method has been employed for the recovery of Pt(IV) and Cr(III) from tapwater and sea-water samples.
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  • 23
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gel permeation chromatography ; Cheese peptides ; Amino acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The nitrogen fraction from cheese, soluble in phosphotungstic acid has been analyzed by gel permeation and high performance liquid chromatography. Elution profiles of this fraction on Sephadex G-10 show that there are no peptides of molecular weight higher than 700 daltons. Six fractions have been obtained. The first one has the peptides and some amino acids. Fractions II to VI contains mostly free amino acids. Fraction I has been separated into many peaks by HPLC. Six or seven of these peaks are presumed to correspond to peptides.
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  • 24
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Small-bore packed columns ; Air pollutants ; PAH, nitro and oxy-PAH ; Aldehydes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The preparation of small bore columns (1 mm i.d.) packed with reversed-phase materials is described. High efficiency (Hmin=2 dp), coupled with a small C term (0.005 sec) have been obtained so that high speed can be combined with sufficient resolution for the separation of complex organic mixtures. These columns have been used for the separation of air pollutants dispersed in different matrices (air, particulate matter and rain water). Practical applications include the determination of aldehydes in air and emission samples, PAHs, nitrated and oxygenated PAHs in dust sampled from the stack of an industrial emission or collected in a urban area and the analysis of organic components dissolved in rain water collected at a rural site. Specific detection of these pollutants has been achieved by connecting small bore columns to UV absorbance, voltammetric and fluorimetric detectors. Mass spectra of some specific components have been recorded using the off-line technique.
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  • 25
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    Chromatographia 23 (1987), S. 825-828 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gasoline ; Single-ring aromatic hydrocarbons ; Polycyclic aromatic hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This work reports a rapid and easy procedure for the analysis of the aromatic fraction in gasoline. No sample pretreatment is required, since the gasoline is diluted in methanol and directly injected into a liquid chromatograph. A spectrophotometer detector and a spectrofluorimeter detector are used in series. The procedure has been applied to a large number of Italian and European refined gasoline samples.
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  • 26
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    Chromatographia 23 (1987), S. 109-111 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Normal and reverse phase ; Aldicarb ; Aldicarb sulfoxide ; Aldicarb sulfone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Aldicarb, aldicarb sulfoxide, and aldicarb sulfone were chromatographed on an octyl-silica bonded-phase column and on an unmodified silica column using acetonitrile/water mobile phases. The elution order of the analytes from the silica column was different from that using the octyl-silica bonded phase and allowed confirmation of residues of aldicarb sulfoxide in citrus nectar. Isocratic elution of the unmodified silica column allowed rapid sample throughput.
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  • 27
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ligand-exchange chromatography ; Chiral bonded phase ; Racemate resolution ; Amino acids
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    Topics: Chemistry and Pharmacology
    Notes: Summary The resolution of racemates on chiral chemically bonded silica gel by high-performance ligand-exchange chromatography is described. The stationary phase was prepared by bonding (−) trans 1,2 cyclohexanediamine to silica gel through the coupling agent 3-glycidoxypropyl silane. The resolution of several α-amino acids and of compounds of pharmaceutical interest is reported.
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  • 28
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    Pharmacy world & science 9 (1987), S. 305-314 
    ISSN: 1573-739X
    Keywords: Atrial natriuretic factor ; Blood pressure ; Chemistry ; Diuresis ; Homeostasis ; Kidney ; Muscle, smooth ; Natriuresis ; Receptors, endogenous compounds ; Renin-angiotensin system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract It is now known that cardiac atria play an important role in blood pressure and volume regulation. Mechanical distension of the atria results in the release of a potent diuretic and natriuretic agent or agents termed the atrial natriuretic factor (ANF). Several structurally related forms of ANF exist in man and it is thought that these represent precursory forms of a single optimally active molecule and/or the presence of more than one form of active ANF. The chemical structure of ANF between different mammalian species is similar. ANF receptors have been identified in kidney, brain, vascular endothelial and smooth muscle cells, tracheal and bronchial smooth muscle and the adrenal glands of many mammalian species, including man. This would suggest that ANF influences blood pressure and volume homoeostasis by affecting any one of a number of biochemical or physiological mechanisms via different target tissues. ANF is now considered a potentially valuable therapeutic agent for the treatment of hypertension and congestive heart failure. Synthesis of potent receptor antagonists could be extremely useful in the treatment of various clinical situations which are produced or complicated by endogenously produced ANF, such as chronic orthostatic hypotension.
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  • 29
    ISSN: 1573-1561
    Keywords: 2-methyl-3-buten-2-ol ; cis-verbenol ; ipsdienol ; ipsenol ; sex ratio ; attraction ; inhibition ; Ips duplicatus ; Thanasimus ; switching ; Ips typographus ; Coleoptera ; Scolytidae ; Ceeridae
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The density of bark-beetle colonization of a tree could be regulated by a quantitative effect of the pheromone signal from beetles in the tree (cessation of release of attractive pheromone) or by a qualitative effect (production of pheromone components inhibiting attraction). The quantitative hypothesis was tested onIps typographus by varying the release rate of the two known attractive compounds, 2-methyl-3-buten-2-ol (MB) and (4S)-cis-verbenol (cV). The highest number of beetles were captured at traps with the highest release rates. The catch was nearly proportional to the release of MB and cV at a distance between traps of 12 m or more. At 6-, 3-, and 1.5-m distances between traps deployed in a triangular arrangement there was still a good discrimination between release rates, but relatively more beetles, especially males, were caught on the blank. The lower release rates caught an equal sex ratio while the highest release rate caught only about 30% males. The qualitative hypothesis was tested by releasing the suspected inhibitors ipsdienol (Id) and ipsenol (Ie), from traps in the same amounts as cV. Only small effects were noted forI. typographus. However, the competitorI. duplicatus was attracted to Id and inhibited by Ie, while the predatorThanasimus formicarius was attracted to both compounds. On the other hand, when the ratio of Id or Ie to cV was 10∶1 or 0.1∶1 rather than 1∶1, they affected the numbers ofI. typographus attracted. A small amount of Id combined with the attractants increased trap catch, while large amounts of Id or Ie decreased attraction, especially when combined. Attack density regulation is modeled as an effect of both quantitative and qualitative mechanisms acting in sequence.
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  • 30
    ISSN: 1573-1561
    Keywords: Sex pheromone ; 6,12-dimethylpentadecan-2-one ; ketone ; banded cucumber beetle ; Diabrotica balteata ; Chrysomelidae ; Coleoptera ; attractant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A sex pheromone produced by female banded cucumber beetle adults,Diabrotica balteata LeConte, was isolated from volatiles trapped on Porapak Q and identified as 6,12-dimethylpentadecan-2-one. The structure was elucidated by spectroscopic analyses and confirmed by synthesis. The synthesized racemic compound was equal to the purified natural pheromone in eliciting responses by banded cucumber beetle males to field traps. A doseresponse characteristic was demonstrated for the racemic material formulated on filter paper or rubber septa and placed in field traps. The absolute configuration at the C-6 and C-12 positions was not established.
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  • 31
    ISSN: 1573-1561
    Keywords: Host attraction ; pheromone ; Pinus sylveslris ; trans-verbenol ; 3-carene-10-ol ; myrtenol ; verbenone ; EAG ; kairomone ; Blastophagus ; Tomicus minor ; Tomicus piniperda ; Coleoptera ; Scolytidae ; pine shoot beetles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The chemical ecology of host- and mate-finding in the pine shoot beetles,Tomicus minor andT. piniperda, was studied in southern Sweden. Beetles were collected in the field from defined attack phases on Scots pine. Using gas chromatography-mass spectroscopy, a number of oxygen-containing monoterpenes, e.g., 3-carene-10-ol, myrtenol,trans-verbenol, and verbenone, were identified from hindgut extracts of both sexes of both species. Compared toT. minor,T. piniperda contained additional compounds and in larger amounts. The amounts were highest in both species at the time when the beetles had bored into contact with the resin-producing xylem-phloem tissue. The synthesis of (1S,6R)-3-carene-10-ol by photooxidatipn of (+)-(1S,6R)-3-carene is described. In comparative electroantennogram (EAG) measurements on males and females of both species, the most active of the tested compounds wastrans-verbenol. Laboratory bioassays of walking beetles showed thatT. piniperda was attracted to uninfestèd pine logs.T. minor was more strongly attracted to pine logs infested with females than to uninfested pine logs, indicating a female-produced aggregation pheromone. Field tests confirmed thatT. piniperda was strongly attracted to pine logs. The attraction ofT. minor to logs was significant only when logs were combined with racemictrans-verbenol and (1S,6R)-3-carene-10-ol.T. minor was also attracted to a combination of these monoterpene alcohols alone. We suggest that host and mate location inT. piniperda is achieved by means of a kairomone composed of host monoterpenes, whileT. minor utilizes a primitive pheromone synergized by host odors. Evolution of host colonization strategies of the two beetles are discussed.
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  • 32
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    Journal of chemical ecology 13 (1987), S. 1689-1694 
    ISSN: 1573-1561
    Keywords: Feeding deterrents ; Aulacophora foveicollis ; red pumpkin beetles ; Coleoptera ; Chrysomelidae ; Momordica charantia (bitter gourd) ; cucurbitane triterpenes ; momordicine ; Cucurbitaceae
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The triterpenoids isolated from the leaves ofMomordica charantia Linn (bitter gourd) were found to elicit feeding-deterrent activity against red pumpkin beetles (Aulacophora foveicollis Lucas). The most abundant triterpenoid which deterred feeding was identified as momordicine II, 23-O-β-glucopyranoside of 3,7,23-trihydroxycucurbita-5,24-dien-19-al. A concentration of 3200μg/ml and above of the triterpenoids caused significant reduction of feeding by red pumpkin beetles in in vitro bioassay experiments, which compared favorably with the levels of triterpenoids inM. charantia leaves found in nature.
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  • 33
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    Journal of chemical ecology 13 (1987), S. 1871-1879 
    ISSN: 1573-1561
    Keywords: Sex pheromone ; drugstore beetle ; Stegobium paniceum L. ; Coleoptera ; Anobiidae ; stegobiol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract New sex pheromone component of femaleStegobium paniceum L. was isolated and identified as 2,3-dihydro-2,3,5-trimethyI-6-(1′-methyl-2′-hydroxybutyl)-4H-pyran-4-one, stegobiol, by spectral data and chemical conversion from stegobinone. Relative configuration at C-2, C-3, and C-1′ was determined as 2S,3R,1′S by the conversion from (2S,3R,1′R)-stegobinone. This new sex pheromone elicits the pheromonal response from the species.
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  • 34
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    Journal of chemical ecology 13 (1987), S. 1139-1146 
    ISSN: 1573-1561
    Keywords: Colorado potato beetle ; Leptinotarsa decemlineata ; Coleoptera ; Chrysomelidae ; Solanum tuberosum ; Lycopersicon hirsutum f.glabratum ; chemoattraction ; masking ; mixed cropping ; olfactory orientation ; searching behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Walking tracks of Colorado potato beetles,Leptinotarsa decemlineata Say, were recorded on a locomotion-compensator in response to wind, odors of host plantsSolanum tuberosum L. and nonhost plantsLycopersicon hirsutum f.glabratum C.H. Mull, and to mixtures of these plant species. Host-plant odor induced positive anemotactic responses in starved females, whereas odor of the nonhostL. hirsutum was neither repellent nor attractive. The attractiveness of host-plant odor, however, was neutralized in the odor blend of plant species. Masking the attractive host-plant odor will hinder the beetle's searching for host-plant patches, and this principle may be exploited in pest control by mixed cropping.
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  • 35
    ISSN: 1573-1561
    Keywords: Common furniture beetle ; Anobium punctatum ; drugstore beetle ; Stegobium paniceum ; Coleoptera ; Anobiidae ; sex pheromone ; stegobinone ; 2,3,dihydro-2,3,5-trimethyl-6-(1-methyl-2-oxobutyl)-4H-pyran-4-one ; behavior ; electroantennogram ; species specificity
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    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Observations and reports on the common furniture beetleAnobium punctatum suggested that, on emergence, females use a sex pheromone to attract males. GLC analysis of ovipositor extracts showed the presence of a single component, which was found to be active by EAG and coupled GLC-EAG techniques, and to attract males in both walking and flying assays. The pheromone was identified by GC-MS as 2,3-dihydro-2,3,5-trimethyl-6-(1-methyl-2-oxobutyl)-4H-pyran-4-one (stegobinone), which is the sex pheromone of another anobiid, the drugstore beetle,Stegobium paniceum. MaleA. punctatum responded equally to ovipositor extracts of either species, at both the sensory (EAG) and behavioral levels, which poses the question as to how species specificity in mate attraction is achieved.
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  • 36
    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Coleoptera ; Scolytidae ; bark beetle ; western pine beetle ; pheromone ; interruption ; behavior ; release device
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The number of western pine beetles,Dendroctonus brevicomis, trapped at the center of three 90 × 90-m plots was reduced during a 16-hr period after surrounding an attractive source ofexo-brevicomin, frontalin, and myrcene with 16, 48, or 168 sources of the same attractant. Compounds were released from the center of the plot at 1 mg/16 hr/compound, and from the surrounding sources at 4–280 mg/16 hr/compound. About half of these amounts was released between 1530 hr and 1930 hr, the period of peak beetle flight. No treatment differences were apparent in reduction of catch within the range of release rates and spacings tested. When compounds were released continuously from 168 stations for 17 days, catch at the center of a plot was generally lower than catch before or after this period, but fluctuated daily. More beetles were caught on traps hung on ponderosa pines within a plot and the number of these traps catching beetles was greater when compounds were released from all stations than from only the center station. Beetles caught on traps were attracted into the plots from the surrounding forest, but appeared to be dispersed within the plot when compounds were released from many stations.D. brevicomis attacked at least 91 trees in the plots, of which 25 were killed during two summers.
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  • 37
    ISSN: 1573-1561
    Keywords: Spodoptera frugiperda ; Lepidoptera ; Noctuidae ; Acalymma vittatum ; Coleoptera ; Chrysomelidae ; brine shrimp ; Artemia salina ; insecticides ; antifeedants ; Meliaceae ; neem ; limonoids ; azadiractin ; seeds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Hexane and ethanol extracts of seeds from 22 species of plants of the family Meliaceae from a number of countries were prepared. The extracts were submitted to antifeedant and toxicity bioassays utilizing fall armyworm [Spodoptera frugiperda (J.E. Smith)] (Lepidoptera: Noctuidae) larvae and striped cucumber beetle [Acalymma vittatum (F.)] (Coleoptera: Chrysomelidae) adults. Toxicity tests were also performed with brine shrimp,Anemia salina Leach. Feeding inhibition and mortality produced by some of these extracts were comparable to and, in certain cases, slightly greater than the effects produced by comparable neem (Azadiracta indica A. Juss.) seed preparations. Brine shrimp toxicity data do not extrapolate to insect activity, and vice versa.
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  • 38
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    Journal of chemical ecology 13 (1987), S. 733-739 
    ISSN: 1573-1561
    Keywords: Sitona lineatus ; pea and bean weevil ; pea leaf weevil ; Coleoptera ; Curculionidae ; aggregation pheromone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The attraction ofS. lineatus to live baits comprisingS. lineatus feeding onVicia faba (L.) was studied in a field experiment in the early spring. There was clear evidence that maleS. lineatus produced an aggregation pheromone which attracted approximately equal numbers of both sexes from overwintering sites. No evidence was obtained for the production, in the spring, of any semiochemical by female weevils.
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  • 39
    ISSN: 1573-1561
    Keywords: Semiochemicals ; pheromones ; enantiomers ; western balsam bark beetle ; Dryocoetes confusus ; Coleoptera ; Scolytidae ; exo- andendo-brevicomin ; trans-verbenol ; verbenone ; myrtenol ; trans-pinocarveol ; cis- andtrans-p-menthen-7-ol ; 3-caren-10-ol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The most prominent beetle-produced volatiles identified in the abdominal extracts of maleDryocoetes confusus Swaine after they had bored for 24 hr in logs of subalpine fir,Abies lasiocarpa (Hook.) Nutt. were:exo andendo-brevicomin,trans-verbenol, verbenone, myrtenol,trans-pinocarveol,cis- andtrans-p-menthen-7-ol, 3-caren-10-ol, and several monoterpenes and sesquiterpenes. Myrtenol was the only conspicuous compound in extracts from males that had been exposed toA.lasiocarpa resin volatiles for 24 hr. Laboratory bioassays indicated that both (−)- and (+)-exo-brevicomin were attractive to femaleD. confusus, and that the (−) enantiomer did not inhibit response to its antipode. Results from field trapping experiments indicated that bothero-brevicomin and myrtenol are aggregation pheromones forD. confusus.exo-Brevicomin baits were effective in causing attack byD. confusus on baited and surrounding trees, suggesting that this pheromone may have utility in manipulating populations of the beetle.
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  • 40
    ISSN: 1573-1561
    Keywords: Medicago sauva ; alfalfa ; Hypera brunneipennis ; H. postica ; Coleoptera ; Curculionidae ; alfalfa weevil ; host-plant resistance ; bioassay ; feeding deterrency ; ovicide ; antigrowth ; coumarins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A resistant line of alfalfa was studied in an attempt to identify possible chemical factors responsible for alfalfa weevil (Hypera brunneipennis) resistance. Bioassays were developed to measure ovicidal, larval development, pupation, and adult development rates. Serial alfalfa extracts of a weevil-resistant line showed no effect in the bioassays when compared to those of a weevil-susceptible line. It was concluded that resistance substances are not present but that resistant lines are simply more tolerant to weevil attack. Alfalfa constitutents and synthetic analogs were also screened in the egg hatch bioassay. Among these were a series of 3-acyl-4-hydroxycoumarins. 3-Acyl-4-hydroxycoumarins with short-chain acyl groups showed good ovicidal rates, but activity decreased with increasing length of the acyl group.
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  • 41
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    Journal of chemical ecology 13 (1987), S. 1707-1723 
    ISSN: 1573-1561
    Keywords: Biosynthesis ; Coleoptera ; Tenebrionidae ; Tribolium brevicornis ; prostaglandin ; allomones ; synthetase inhibitor ; defensive secretion ; 2′-hydroxy-4′-methoxyacetophenone ; 2′-hydroxy-4′-methoxypropiophenone ; methyl 2,5-dihydroxy-6-methylbenzoate ; methyl 2,5-dihydroxy-6-efhylbenzoate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The defensive secretion ofTribolium brevicornis contains 12 organic components, including quinones, hydroquinones, hydrocarbons, aromatic ketones, and aromatic esters. The two ketones, 2′-hydroxy-4′-methoxyacetophenone and 2′-hydroxy-4′-methoxypropiophenone, and the two esters, methyl 2,5-dihydroxy-6-methylbenzoate and methyl 2,5-dihydroxy-6-ethylbenzoate, represent ca. 0.25% of the biomass of the beetles. Mass spectral and NMR analyses were used to elucidate the structures of all components. The ketones are potent prostaglandin synthetase inhibitors (PSI), and the esters are suspected to be PSI.
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  • 42
    ISSN: 1573-1561
    Keywords: Dendroctonus ponderosae ; mountain pine beetle ; Coleoptera ; Scolytidae ; monoterpene metabolism ; monoterpene alcohols ; pheromones ; allylic hydroxylation ; anti-Markovnikov hydration ; Pinus ponderosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Abdominal volatiles of female mountain pine beetles,Dendroctonus ponderosae Hopkins, fed in ponderosa pine,Pinus ponderosa Dougl. ex Laws, and in lodgepole pine,P. contorta var.latifolia Engelmann, were analyzed by gas chromatography and coupled gas chromatography-mass spectrometry and were found to comprise host oleoresin components and beetle-produced alliylic alcohols, aldehydes, and ketones derived from host monoterpenes. Neitherexo- andendo-brevicomin nor frontalin were detected. Three metabolic pathways are proposed to account for the distribution of beetle-produced monoterpene alcohols. The first pathway involves hydroxylation of monoterpene substrates on allylic methyl groups which areE to a methylene or vinyl group. This oxidation pathway is indiscriminate with respect to substrate and probably functions to detoxify monoterpenes. A second pathway, which hydroxylates theendo-cyclic methyleneE to a vinyl methyl group of bicyclic monoterpenes to give almost exclusively thetrans alcohol, is hypothesized to be involved in pheromone production. A third detoxification pathway involves anti-Markovnikov addition of water to theexo-cyclic double bond of β-phellandrene to give predominantlytrans-2-p-menthen-7-ol.
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  • 43
    ISSN: 1573-1561
    Keywords: Oryzaephilus surinamensis ; Oryzaephilus mercator ; aggregation pheromone ; macrolide lactone ; (Z)-3-dodecen-11-olide ; (Z,Z)-3,6-dodecadien-11-olide ; (Z,Z)-5,8-tetradecadien-13-olide ; (Z, Z)-3,6-dodecadienolide ; (Z)-5-tetradecen-13-olide ; enantiomers ; racemate ; chirality ; aggregation behavior ; Coleoptera ; Cucujidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The response of the sawtoothed grain beetle,Oryzaephilus surinamensis (L.), and the merchant grain beetle,O. mercator (Fauvel), to synthetic racemic and chiral macrolide aggregation pheromones was assessed in pitfall olfactometers.O.mercator utilizes theR enantiomers of (Z)-3-dodecen-11-olide and (Z,Z)-3,6-dodecadien-11-olide.O. surinamensis utilizes theR enantiomers of (Z,Z)-3,6-dodecadien-11-olide and the Synergist (Z,Z)-5,8-tetradecadien-13-olide in combination with achiral (Z,Z)-3,6-dodecadienolide. For both species, the racemates of the respective chiral pheromones were effective attractants. The respectiveS enantiomers were inactive for both species and had no effect on the biological activity of the active antipodes. No diel periodicity in responsiveness to pheromones was detected inOryzaephilus spp. reared either on a 12∶12 light-dark photoperiod or in darkness. Nonpheromone macrolides, naturally released in trace amounts byOryzaephilus spp., did not affect the aggregation response of either species to its pheromones when these additional macrolides were combined with the pheromone mixtures.
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  • 44
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    Chromatographia 23 (1987), S. 320-324 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Microbore capillary columns ; Polymer based octadecylsilica bonded phase ; Fat soluble vitamins
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    Topics: Chemistry and Pharmacology
    Notes: Summary Separation behavior of fat soluble vitamins on various chemically bonded materials in non-aqueous reversedphases microcolumn liquid chromatography has been investigated. The best performance was found on a polymer-based octadecyl bonded phase. Optimization of separation for vitamins D2, D3, E and E acetate has been tried using this polymer-based column and it has been found that a binary mobile phase consisting of acetonitrile and methanol gave complete separation of fat soluble vitamins.
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  • 45
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    Chromatographia 23 (1987), S. 331-336 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Microbore columns ; Injection techniques
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    Topics: Chemistry and Pharmacology
    Notes: Summary This paper focuses attention on the potentially larger signal-to-noise ratios produced by microbore columns in comparison with conventional columns. The increased chromatographic signals by the application of microbore columns are due to the lower chromatographic dilution of elution profiles which are proportional to the square of the column inner radius. Generally less than 1μl sample should be injected into microbore systems to obtain the full benefit of the column performance. However, since more sample can be loaded on conventional columns compared to microbore columns the advantage of improved signal-to-noise ratio can only be realised in situations where very little sample is available. To inject more than 1μl sample, at the same time avoiding extra band-broadening effects, suitable injection techniques must be available. In this study three injection methods for microbore systems that meet this condition, are studied and compared.
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  • 46
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Anion-exchange chromatography ; Xylenol orange ; Separation of nickel and zinc
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    Topics: Chemistry and Pharmacology
    Notes: Summary A liquid chromatographic procedure for separating nickel and zinc has been developed. Xylenol orange, which is one of the sensitive and commercially available color-forming agents, was used as a component of the mobile phase. The two ions could be separated on weak anion-exchange gels within 10 min. The procedure was suitable for the determination of nickel and zinc in relatively pure solutions with fairly high sensitivity. The described liquid chromatographic analysis would be also potentially applicable for any aqueous sample containing trace levels of metal cations at 1–10 ppm.
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  • 47
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Oligosaccharides ; Interference by salts ; Complex biological samples ; Enzymatic assays
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    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the determination of oligosaccharides in samples of high salt content by RP-HPLC with water as eluent and refractive index detection. The samples, mussel processing wastes which are used as media for microfungus and yeast cultures and hence for enzymatic assays (amilolitic capacity) of these microorganisms that develop within the wastes, have been treated with ethanol to precipitate the macromolecular organic matter and desalted by a modified mixed bed resin before chromatographic analysis is carried out.
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  • 48
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    Chromatographia 23 (1987), S. 579-582 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Backflush technique ; Coal-derived procucts ; Separation of phenolic compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A rapid method was developed for the direct extraction of phenolic compounds from coal-derived products and subsequent isocratic HPLC analysis in a reversed-phase system by using the backflush technique.
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  • 49
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Non-porous gel ; Alkaline-earth cations ; Arsenazo III
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    Topics: Chemistry and Pharmacology
    Notes: Summary A liquid chromatographic procedure for separating alkaline-earth-metal cations with a non-porous gel column has been developed. Arsenazo III, which is one of the sensitive and commercially available color-forming agents, was used as a component of the mobile phase. Magnesium and calcium could be separated on the nonporous gel column within 55 seconds. The procedure was suitable for the separation of alkaline-earth-metal cations in relatively pure solutions with high sensitivity. Because of its rapidity the described procedure is also potentially applicable for any aqueous sample.
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  • 50
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Biphenols ; Dihydroxyphenylpropanes ; Voltammetric detection ; UV photometric detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention behaviour of mono- and dihydroxy derivatives of biphenol and bis(hydroxyphenyl)propanes was studied on chemically bonded C-18, CN-, phenyl, phenoxypropyl- and NH2 stationary phases and on silica gel. The effects of the mobile phase, i.e., of the methanol content, the ionic strength, pH and the contents of cationic and anionic ion-pairing agents on the retention data were investigated. In the reversed-phase systems, all the substances are satisfactorily separated except for 3- and 4-hydroxybiphenyl; these isomers can be separated on silica gel, using a mixture of heptane and propanol as the mobile phase. Sodium dodecylsulphate, present at concentrations higher than the critical micelle concentration (about 10−2 M, depending on the methanol content), causes a decrease in the retention times and an improvement in the separation. UV absorption spectra, calibration curves and the detection limit values were obtained at two wavelengths and at various salt concentrations in the mobile phase. Hydrodynamic voltammograms of the solutes were measured in a carbon fibre detector and the calibration curves and detection limit values were measured at the optimal voltage (+1.2 V/Ag/AgCl) as a function of the mobile phase composition. For most test substances voltammetric detection is two to three times more sensitive than UV detection. The combination of a UV and a voltammetric detector in series has been utilized to identify the products of microbial degradation of biphenyl.
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  • 51
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thin-layer chromatography ; Ion pairing system ; Log P prediction ; Group contributions
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    Topics: Chemistry and Pharmacology
    Notes: Summary A group of 17 β-carbolines was studied in HPLC and TLC systems in order to predict their partition coefficients (log P values). On account of the basic or acid character of some of these compounds, an ion pairing system gave the best results. Both HPLC and TLC data were comparable for log P prediction but severe pH conditions required the use of TLC plates. Retention data are quantitatively related to lipophilicity (expressed as the Hansch constant) and polarity (as the inductive constant) of the solute molecule.
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  • 52
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chitosan-coated silica gel ; Nucleotides ; Amino acids
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    Topics: Chemistry and Pharmacology
    Notes: Summary A new stationary phase was prepared by immobilizing the chitosan, a natural hydrophilic polymer, on microparticolate silica gel. The effect of the polarity, pH and ionic strength of the mobile phase has been studied in order to find optimal conditions for the separation of nucleotides and aminoacids. The influence of the properties of the mobile phase on the retention was examined, allowing to employ the chitosan-coated silica gel both to anion exchange and adsorption, depending on the pH and the polarity of the eluent used.
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  • 53
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed-phase systems ; Phases-solute interactions ; Molecular polarizability
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    Topics: Chemistry and Pharmacology
    Notes: Summary Variations in the electrostatic interaction have been studied using polycyclic aromatic hydrocarbons as standard compounds and different reversed-phase HPLC systems. Various methanol-water and acetonitrile-water binary mixtures were applied as the mobile phase. The stationary phases investigated consist of octadecylsilica and arenyl-silica. Using polarizability, dipole moment and ionization potential values of the solutes and mobile phase components as molecular descriptors an electrostatic interaction model is proposed.
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  • 54
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    Chromatographia 23 (1987), S. 93-96 
    ISSN: 1612-1112
    Keywords: Paper chromatrography ; Column liquid chromatography ; Copper-impregnated zinc silicate ; Separation of amines
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    Topics: Chemistry and Pharmacology
    Notes: Summary Papers impregnated with Cu(II) sorbed on zinc silicate have been used to study the ligand exchange chromatographic behavior of amines. RF values of 16 amines have been studied in 6 different systems. On the basis of differences in RF values various analytically important qualitative separations of amines on impregnated papers and quantitative separations on columns of copper(II) sorbed on zinc silicate have been achieved.
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  • 55
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Linear isotherms ; Octadecyl bonded silica ; Styrene divinylbenzene ; Frontal analysis
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    Topics: Chemistry and Pharmacology
    Notes: Summary Two reversed-phase LC systems were investigated by frontal analysis for the determination of linear chromatographic conditions, as defined according to the isotherm concept. The Partisil ODS-3 bonded silica and the PRP-1 polystyrene-divinylbenzene resin were used as stationary phases together withtrans-2-hexen-al as test solute and methanol-water mixtures as mobile phases. Particular attention was paid to the respective influence of the two main parameters which may cause sorbent overloading, that is, the capacity factor (k′) and the solute concentration in the mobile phase (Cm). Provided that k′Cm≤10−2 M, linear chromatographic behaviour was observed for both sorbents, the maximum capacities of which were found greater than 1mmolg−1.
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  • 56
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    Chromatographia 23 (1987), S. 189-194 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Instrument bandbroadening by extrapolation
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    Topics: Chemistry and Pharmacology
    Notes: Summary Methods to determine the contribution of the chromatographic equipment to the total band broadening which involve replacing the column by a union or a capillary tube are not suitable as they involve a fundamental change in the chromatographic system. The linear extrapolation method, based on the estimation of the relative influence of the instrument variance on solutes with different capacity factors, is a more attractive alternative method since the column remains in the chromatographic system. This method is only valid when a number of conditions are satisfied. By meeting these conditions the error in the instrument variance by using the linear extrapolation method was determined. At the same time, ways to minimise these errors were studied. Use of the linear extrapolation method in combination with conventional columns of 4.6 mm i.d. appears to yield inaccurate results. In combination with microbore columns the method can be used, provided the columns have a maximum length of 5cm and contain a packing material with a particle size of 2 or 3μm. The error in the determined instrument variance is then of the order of 2μl2.
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  • 57
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    Chromatographia 23 (1987), S. 209-214 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Review of triglyceride analysis ; Column temperature gradients ; Combined LC and other techniques
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    Topics: Chemistry and Pharmacology
    Notes: Summary The present review cites 54 papers dealing with reversephase HPLC analysis of triglycerides. The objective of the review was not merely to list the main contributions made in recent years but also to present a discussion of those papers representing qualitative advances and improvements helping to obviate the difficulties associated with this type of analysis. The use of mobile phase polarity and column temperature gradients and the combination of HPLC with other analytical methods such as mass spectrometry or GLC analysis of fatty acids are examples of such contributions.
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  • 58
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    Chromatographia 23 (1987), S. 254-256 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Synthesis of stationary phases ; Influence of surface pH ; Influence of temperature, concentration and reaction ; time
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    Topics: Chemistry and Pharmacology
    Notes: Summary A new way to produce liquid chromatographic stationary phases is suggested. The method is based upon a solide-phase reaction between the silica surface and the adsorbed silane molecules. The role of surface pH is demonstrated. The influence of other reaction conditions (concentration of the silane solution, effect of temperature and reaction time) is discussed.
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  • 59
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chiral stationary phases ; Succinimido carbamate intermediates ; Amino acid enantiomers
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    Topics: Chemistry and Pharmacology
    Notes: Summary Chiral stationary phases (CSPs) for liquid chromatography were prepared by the way of an activated carbamate intermediate. The amino group of aminopropylsilyl silica gel was first activated by carbamylation with disuccinimido carbonate (DSC). The obtained activated carbamate silica gel (ACsil) proved useful as an intermediate for the preparation of urea-type CSPs. The reaction of ACsil with (S)- of (R)-1-(α-naphthyl)-ethylamine gave naphthylethylurea type CSPs. These CSPs were also obtained directly from aminopropylsilyl silica gel by its reaction with optically active (S)- or (R)-succinimido 1-(α-naphthyl)ethyl carbamate (SINEC). Several phenylthiohydantoin amino acid enantiomers and p-bromophenylcarbamyl amino acid enantiomers were resolved on the CSPs by elution with aqueous mobile phase.
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  • 60
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gas chromatography ; Bonded silica ; Residual silanol groups
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    Topics: Chemistry and Pharmacology
    Notes: Summary Silanol groups of chromatographic material surfaces were determined by chemical reaction with methyl-lithium. Evolved methane was measured by a gas chromatographic method using a column packed with molecular sieves. This chromatographic technique leads to very reproducible results, particularly for the control of the hydroxylation of a silica gel and for the analysis of residual groups at the surface of bonded silica.
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  • 61
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Aldehydes ; Annular denuder ; Environmental analysis
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    Topics: Chemistry and Pharmacology
    Notes: Summary An improved procedure for the HPLC determination of C1−C3 aldehydes in environmental samples is described. These air pollutants are quantitatively collected on annular denuders coated with 2,4-Dinitrophenylhydrazine and analyzed as hydrazone derivatives by HPLC with UV absorbance and voltammetric detection. Collection efficiencies of aldehydes are reported and compared with other available methods. Practical examples of the application of the method are given.
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  • 62
    ISSN: 1612-1112
    Keywords: Estriol ; Urine ; Menstrual Cycle ; Column liquid chromatography
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    Topics: Chemistry and Pharmacology
    Notes: Summary A high-performance liquid chromatography (HPLC) assay for estriol in nonpregnancy urine is described. After Enzymic hydrolysis, the estriol is extracted from urine by the sorbent trap technique utilizing graphitized carbon black (Carbopack B). After some washing steps, estriol is desorbed by a suitable solvent system. After solvent removal, the sample is injected into an HPLC column for estriol quantification. Analytical recovery of estriol was 96.1%. The precision of the method was 2.6 and 4.9% respectively at 145 and 10.6ng/ml of urine. The limit of sensitivity was set at 0.8 ng/ml of urine. The mean contents of estriol in the follicular and luteal phases were respectively 11.3 and 38.8 ng/ml of urine.
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  • 63
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Isohydric solvents ; Butyrophenones ; Direct-silica gel
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    Topics: Chemistry and Pharmacology
    Notes: Summary The behaviour of butyrophenones in high performance liquid chromatography on silica gel using isohydric solvent systems has been studied. The influence of column temperature, water content, acidity and polarity of isohydric solvents on the retention, column efficiency and resolution of a series of butyrophenones have been investigated. Through the results obtained more insight has been gained into the theoretical aspects of the adsorption process on silica gel with isohydric solvent systems.
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  • 64
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed-phase separation ; Oligodeoxyribonucleotides ; Isolation of pure material
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    Topics: Chemistry and Pharmacology
    Notes: Summary A reversed-phase chromatographic column suitable for the purification of chemically synthesized large oligodeoxyribonucleotides (oligo-DNA) was prepared. The specifications of this column are; the selected silica (Toyo Soda silica) with large pore size (at least 150 Å) and small particle diameter (5 μm desired) should be grafted only with monochloro alkylating reagent of long alkyl chain (sufficiently C18) so that the carbon content of the resultant packing material is 15–16%. Using this column, we could isolate the targeted large oligo-DNA (up to 50mer) in a large scale (75 μg per one cycle) from the impurities in the reaction mixture formed during the automated synthesis by the phosphite method.
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  • 65
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    Chromatographia 23 (1987), S. 292-300 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Separation of sugars ; Review
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    Topics: Chemistry and Pharmacology
    Notes: Summary This contribution to the problems of carbohydrate (sugar) column liquid chromatography, evaluates several currently used systems (reversed phase octadecylated silica gel, amino modified silica gel, cation exchangers on polystyrene and on silica gel basis, polyol derivatised silica gel and anion exchange systems). The elution pattern, analysis time, column efficiency and column life time expectancy are considered to be the important points for this comparison. The application of silica gel-based cation exchanger and of polyol derivatised silica gel is new to this field. The comparison and/or evaluation tries to be critical and to come to a conclusion for the choice of a recommended system.
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  • 66
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Packings of octadecylated microporous glass ; Dimethadione and trimethadione in serum ; Pancreatic stones
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    Topics: Chemistry and Pharmacology
    Notes: Summary The liquid chromatographic determination of trimethadione (TMO) and its methabolite, dimethadione (DMO) were studied by high-performance liquid chromatography (HPLC) on octadecyl-modified microporous glasses, prepared with toluene solution containing octadecyl-dimethylchlorosilane, using two types of microporous glass with various mean pore diameters and/or specific surface areas. Using acetonitrile-water mixtures as eluents, TMO and DMO in human serum were separated on the glasses studied, but with different degrees of resolution. In this present study, we report the development of a rapid and selective HPLC method for the simultaneous analysis of TMO and DMO in human serum.
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  • 67
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Cross-linked polystyrene ; Characterization of surfaces
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    Topics: Chemistry and Pharmacology
    Notes: Summary The properties of the poly(styrene-divinylbenzene) copolymers PRP-1 and PLRP-S have been studied by infrared spectroscopy and chromatographic techniques. The following results were obtained: PRP-1 and PLRP-S are spectroscopically very similar. Their surfaces are chemically neither homogeneous nor stable during use. Retained nonpolar solutes should be eluted with a mobile phase containing tetrahydrofuran. Uncharged acids and anions can be chromatographed without difficulty. Cations of amines should be chromatographed only with a mobile phase of low pH. Uncharged amino-alcohols cannot be chromatographed without the addition of a competitor.
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  • 68
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chemically bonded phases ; Kinetics of silanization
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    Topics: Chemistry and Pharmacology
    Notes: Summary A wide-pore silica for HPLC with a particle size of 7.5 μm, specific surface area of 360m2/g, pore diameter of 20 nm and pore volume of 2.1 cm3/g was silanized with n-octadecyldimethyl-chlorosilane (ODMCS), n-octadecyldimethylmetoxysilane (ODMMS) and n-octadecyldimethyl-dimethylaminosilane (ODMAS), in sealed glass ampoules. The ligand density obtained with an excess of ODMCS and ODMMS was found to be limited by reaction equilibrium; at low (〈50%) conversion of the surface silanols, the reaction displays pseudo-first-order kinetics. Silanization with ODMAS, which seems to be sterically controlled at higher conversions, yields a relatively high concentration of bonded octadecyl ligands (4.24μmol/m2).
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  • 69
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    Chromatographia 23 (1987), S. 684-685 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Pentafluoroanilinopropyl silica gel ; Donor-acceptor complexes ; Aromatic hydrocarbons
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    Topics: Chemistry and Pharmacology
    Notes: Summary The preparation of a new pentafluoroanilino-phase for HPLC is described. The retention times (tr) of about twenty aromatic hydrocarbons have been determinated. It has been shown that the aromatics were eluted according to the number of rings. The influence of water content in the mobile phase is commented.
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  • 70
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thiol drug analysis ; Derivatization by ethacrynic acid ; Pharmaceutical formulations
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    Topics: Chemistry and Pharmacology
    Notes: Summary A high performance liquid chromatographic method has been developed for the determination of aliphatic thiol drugs, such as N-acetyl-L-cysteine, captopril and mercaptopropionylglycine in pharmaceutical formulations. The procedure involves a precolumn derivatization of the thiol drug with ethacrynic acid followed by reversedphase HPLC separation and UV detection. The conditions for a rapid and selective reaction of the thiols with ethacrynic acid have been investigated. The method proved to be suitable for a reliable and selective quality control of commercial dosage forms of the examined thiol drugs.
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  • 71
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    Chromatographia 23 (1987), S. 657-662 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Post-column derivatization ; Sugar analysis ; Wine characterization
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    Topics: Chemistry and Pharmacology
    Notes: Summary A HPLC system with post-column derivatization for the quantitative analysis of sugars in complex matrices is described. As reagent a 0.2% solution of thymol in concentrated sulfuric acid has been used. The reaction is sensitive with reducing as well as non reducing sugars whereas sugar alcohols are discriminated. With this reagent and separation of sugars at high pH values with an anion exchange column it is possible to detect sugars in the ng range. Hence, it is possible to characterize wines not only by their fructose and glucose content but also by differences in the distribution of the other not fermentable sugars like trehalose, arabinose, galacturonic and glucuronic acid.
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  • 72
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    Chromatographia 23 (1987), S. 709-712 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Polymer-based support ; Aldehydes ; Fluorescence detection
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    Topics: Chemistry and Pharmacology
    Notes: Summary The aldehydes were separated by reversed phase chromatography on a polymer-based support. Acid catalysis on the column was needed to obtain sufficiently fast equilibrium between acetaldehyde and its hydrate. Deuterium labeled acetaldehyde (D3) yielded complete separation from the nonlabeled compound, probably due to a difference in hydratization. Fluorescent products were obtained by reaction between the aldehydes and a mixture of ammonia and dimedone (5.5-dimethyl-1.3-cyclohexanedione). The fluorescence was detected at 460 nm after excitation at 390 nm. A reaction time of 42 seconds at 90°C in a knitted teflon capillary produced detection limits of 0.5 and 1 ng for acetaldehyde and formeldehyde, respectively. A method for preparation of a stable reagent with low background fluorescence is described.
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  • 73
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Thiols and disulfides ; Fluorescence derivatization ; Monobromobimane
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    Topics: Chemistry and Pharmacology
    Notes: Summary The influence of reducing agents (sodium borohydride, tributylphosphine, dithioerythritol and dithiothreitol) on the conversion of disulfides into their parent thiols, with specific application to cysteine was investigated. Dithioerythritol and dithiothreitol were found to be most suitable for this reaction. A contact time of one hour at room temperature provided quantitative reduction as tested using cystine as a pure disulfide standard. A modified fluorescence labelling procedure with monobromobimane followed by reversed-phase HPLC allows quantitation of the parent thiol and the disulfide content when completing the labelling reaction with and without preliminary treatment with reducing agent. The effects of various bimane reducing agent ratios on the yield of the reaction are discussed. Precautions should be taken when dealing with complex matrices with respect to reagent concentrations and ratios.
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  • 74
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Chrial separations ; Succinimido carbamate derivatives ; Propranolol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A chiral derivatization reagent having activated succinimido carbamate moieties were developed for the optical resolution of enantiomeric amines by high-performance liquid chromatography. Succinimido R-(+)- or S-(−)-1-phenylethyl and R-(+)- or S-(−)-1-(α-naphthyl)-ethyl carbamates were synthesized by the reaction of optically active phenylethyl and naphthylethyl amines with discuccinimido carbonate (DSC). These reagents reacted with both primary and secondary amine enantiomers such as amino acids and β-amino alcohols to give the corresponding diastereomeric urea derivatives. These diastereomers were efficiently separated by reversed-phase liquid chromatography and detected by their absorption or the fluorescence of the chromophores. The chiral derivatization procedure was applied to the separation and determination of enantiomeric propranolol in serum.
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  • 75
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Reversed phase operation ; Calculation of optimum solvent composition ; Polymethoxylated flavones
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    Topics: Chemistry and Pharmacology
    Notes: Summary An optimization procedure for the chromatographic separation of polymethoxylated flavones is described. A polyhedron working volume is drawn from a truncated tetrahedron constructed from the four solvents selected. The response function is an n'th degree polynomial the coefficients of which are calculated through the least squares method by means of B=(X′X)−1X′Y in which X′X is the information matrix (X′X)−1 the variance covariance matrix. X is the matrix of the model (polynomial built from the selected experiments) and X′ the transposed matrix. Y is the quality of the chromatogram defined by the resolution of each pair of solutes. An exchange algorithm matrix yields the minimum number of runs necessary to obtain a correct B. Isoresponses curves are drawn by intersection of a cubic volume which includes the polyhedron to give a better insight. An optimal zone is then determined and provides the solvent composition. An optimized chromatogram of 8 methoxylated flavones demonstrates the application of the method.
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  • 76
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    Chromatographia 23 (1987), S. 132-136 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Column liquid chromatography ; Thin-layer chromatography ; Analysis of lactulose in carbohydrate mixtures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Lactulose is a disaccharide with important implications in medicine, nutrition and dairy technology. It has to be determined usually as a minor component in complex matrices containing many other sugars. This paper describes the different chromatographic techniques (planar, liquid and gas chromatography) which have been proposed for the separation and quantification of lactulose in mixtures with other carbohydrates; the advantages of each technique are compared and some features where more research is necessary are outlined.
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  • 77
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    Chromatographia 23 (1987), S. 328-330 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Arylsulphonohydrazides ; On-column hydrolysis ; Fungicides
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    Topics: Chemistry and Pharmacology
    Notes: Summary A number of fungicidally active arylsulphonohydrazides are examined by normal- and reversed-phase liquid chromatography. Although good separations are achieved by reversed-phase LC, difficulties are encountered due to analyte hydrolysis. On the other hand, satisfactory analyses are possible by normal-phase LC particularly on modified silicas.
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  • 78
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    Chromatographia 23 (1987), S. 377-378 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Solid phase extraction ; Codeine and morphine in blood
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    Topics: Chemistry and Pharmacology
    Notes: Summary A rapid and efficient procedure is described for the extraction and analysis of codeine and morphine in whole blood. Red blood cells were fragmented by sonication and the blood sample extracted by passing through a bonded silica column (Bond Elute®). The adsorbed drugs were washed and eluted followed by analysis by HPLC. Recoveries were between 95–100% at 5 ng/ml concentrations.
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  • 79
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    Chromatographia 23 (1987), S. 651-652 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Metoclopramide ; Electrochemical detection
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    Topics: Chemistry and Pharmacology
    Notes: Summary A simple, reproducible liquid-chromatographic method for determination of metoclopramide anti-emetic and anti-spasmodic agent is described. Metoclopramide is extracted from alkalinized plasma into diethylether, then separated with a sperisorb CN column and measured through amperometric detection at +1,4 volt vs Ag/ AgCl. The average extraction recovery was 92%. Standard curves were linear and reproducible from 0.05 to 1.5 mg/ L. Within-day CV was better than 6%.
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    Chromatographia 23 (1987), S. 507-511 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Toluene Diisocyanate in air ; Collector for air sampling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A useful method of sampling and measurement of toluene diisocyanate concentration in atmosphere is described. The sampler consists of glass-fibre filters impregnated with the reagent 1-(2-methoxyphenyl)piperazine1 so that the 2,4 and 2,6 isomers of TDI react to form urea derivatives which are analysed by high performance liquid chromatography in isocratic mode on cyan-amino and C18 bonded phases. A dynamic system was used to generate standard atmospheres of TDI and to validate the sampling method within the humidity range of 0% to 75%. A coated filter, a bubbling solution and an impregnated silica gel were compared as samplers requiring the piperazine reagent in performance experiments.
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  • 81
    ISSN: 1573-1561
    Keywords: Chirality ; enantiomers ; 5-hyroxy-4-methyl-3-heptanone, stereoisomer ; Sitophilus oryzae ; Sitophilus zeamais ; rice weevil ; maize weevil ; aggregation pheromone ; Coleoptera ; Curculionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The chirality of the pheromone of the rice weevil,Sitophilus oryzae (L.), and the maize weevil,S. zeamais (Motschulsky), 5-hydroxy-4-methyl-3-heptanone, was determined using an acetyl lactate derivatization procedure. Maize weevils were shown to produce 〉98% 4S,5R. Determination was more difficult with rice weevils due to a smaller quantity of insect extract, but they were shown to produce at least 92% 4S, 5R. The attractancy of the four synthetic stereoisomers of 5-hydroxy-4-methyl-3-heptanone was tested using rice and maize weevils. As expected, both species were most strongly attracted to the 4S, 5R enantiomer. Maize weevils also showed low but significant responses (P 〈 0.05) to both 4R, 5R and 4S,5S. Rice weevils showed a highly significant (P 〈 0.01) response to 4R, 5S, although it was only about one third the response to 4S, 5R. Thus, (4S,5R)-5-hydroxy-4-methyl-3-heptanone is clearly the major component of the pheromone of bothS. zeamais andS. oryzae.
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  • 82
    ISSN: 1573-1561
    Keywords: Sitophilus zeamais ; Coleoptera ; Curculionidae ; maize weevil ; maize ; resistance ; antifeedant ; sugar content ; hardness ; phenolic content ; ferulic acid ; p-coumaric acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Factors contributing to resistance of maize to infestation by the corn weevilSitophilus zeamais were investigated in four populations of indigenous and improved maize from Belize. Resistance was related to the antifeedant properties of grain as well as sugar content and mechanical hardness. Grain extracts of all populations of maize significantly reduced insect feeding on treated artificial diets when compared to control diets. Consumption of treated diets was negatively correlated with phenolic content of the grain extract. An analysis by GC-MS indicated that ferulic acid andp-coumaric acid were the principal phenolics present in the extracts, and insect feeding was strongly deterred when pure substances were added to insect diets. Fluorescence associated with ferulic acid and related compounds in grain sections was located in the pericarp and aleurone layer and was especially intense in the most resistant grain variety.
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  • 83
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    Journal of chemical ecology 13 (1987), S. 179-184 
    ISSN: 1573-1561
    Keywords: Coleoptera ; Dermestidae ; Attagenus elongatulus ; (Z,Z)-3,5-tetradecadienoic acid ; Pheromone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A simple stereospecific synthesis of (Z,Z)-3,5-tetradecadienoic acid is described based upon coupling of 1-decyne and 3-butyn-1-ol to give 3,5-tetradecadiyn-1-ol. Subsequent reduction of the diyne to (Z,Z)-3,5-tetradecadien-1-ol and oxidation of the dienol gave the desired acid.Attagenus elongatulus were strongly attracted to the pure acid.
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  • 84
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    Journal of chemical ecology 13 (1987), S. 1993-2008 
    ISSN: 1573-1561
    Keywords: Aleochara curtula ; Coleoptera ; Staphylinidae ; female sex pheromone ; cuticular hydrocarbons ; chemical mimicry ; male aggression ; female choice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Immature, starved, or multiply mated males of the staphylinid beetle,Aleochara curtula, mimic their females chemically. The titer of the female sex pheromone components (Z)-7-heneicosene and (Z)-7-tricosene was quantified for various physiological types and both sexes by gas chromatography and correlated with the sexual response of males towards the cuticular hydrocarbon fractions. Modulation of intermale aggression by production of the female pheromone was shown by (1) reduction of the alkene titer of females kept at elevated temperatures, (2) treating live males with the synthetic female pheromone mixture, and (3) gradual amputation of male antennal segments.A. curtula males do not fight against members of otherAleochara species with a different hydrocarbon pattern. Contamination ofA. peschkei males with the hydrocarbon fraction ofA. curtula males, however, provoked the release of aggression. Choosy females reject mating attempts of males bearing the female sex pheromone.
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  • 85
    ISSN: 1573-1561
    Keywords: Diabrotica virgifera virgifera ; Diabrotica barberi ; Coleoptera ; Chrysomelidae ; sex pheromone ; 8-methyl-2-decyl propanoate ; flight-tunnel bioassays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Behavioral analysis of male attraction to stereoisomers of 8-methyl-2-decyl propanoate was conducted withDiabrotica virgifera virgifera andD. barberi using a flight tunnel.D. barberi males were attracted to the 2R,8R isomer only, and the response was inhibited by the addition of 2S,8R.D. v. virgifera males were also attracted to the 2R,8R isomer and were neither attracted nor inhibited by any of the other isomers. Males attracted to the lures displayed a series of behaviors characterized by a slow hovering flight upwind towards the odor source. While significant numbers of males of both species landed on the pheromone lure, none attempted copulation, indicating that other cues are necessary to induce this behavior.
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  • 86
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    Journal of chemical ecology 13 (1987), S. 681-699 
    ISSN: 1573-1561
    Keywords: Cucurbita ; Diabrotica undecimpunctata howardi ; Diabrotica virgifera virgifera ; floral volatiles ; cucurbitacins ; Cucurbitaceae ; Coleoptera ; Chrysomelidae ; host selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Cultivars representing three species ofCucurbita were examined for blossom preference byDiabrotica spp.C. maxima cultivars were found to be preferred byD. undecimpunctata howardi over those ofC. pepo andC. moschata.D. virgifera virgifera preferredC. maxima and the “Connecticut Field” cultivar ofC. pepo.C. moschata and other cultivars ofC. pepo were not preferred. Cultivars were examined for differences in floral volatile release, blossom cucurbitacin content, and pollen content of male blossoms.C. maxima male blossoms released a larger quantity of volatiles thanC. pepo orC. moschata. Also, onlyC. maxima male blossoms contained cucurbitacins. Cultivars ofC. moschata contained the largest quantities of pollen, but all three species contained relatively large quantities. The data indicate a correspondence ofD. u. howardi distribution in the field with high volatile release rates and high cucurbitacin levels that are found inC. maxima blossoms.D. v. virgifera distribution appears to be somewhat independent of these factors since this species was abundant in blossoms of aC. pepo cultivar as well as cultivars ofC. maxima.
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  • 87
    ISSN: 1573-1561
    Keywords: Plant resistance ; constitutive ; inducible ; soybean ; Mexican bean beetle ; Epilachna varivestis ; Coleoptera ; Coccinellidae ; PI 227687 ; phenyl-propanoid metabolism ; PAL ; TAL ; total phenols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Contrary to constitutive resistance, inducible resistance to Mexican bean beetle (MBB) (Epilachna varivestis) herbivory in PI 227687 soybean leaves was positively correlated with total phenolic content and temporally unique, increasedl-phenylalanine ammonia-lyase (PAL) andl-tyrosine ammonia-lyase (TAL) activities. Initial expression of the induced resistance was localized at or near the site of herbivory. Systemic parameters of the induced resistance also were observed. Inducible MBB resistance in PI 227687 soybeans apparently involves increased phenylpropanoid metabolism.
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  • 88
    ISSN: 1573-1561
    Keywords: Ips typographus ; spruce bark beetle ; Coleoptera ; Scolytidae ; pheromones ; aggregation pheromone ; methylbutenol ; methylbutynol ; (S)-cis-verbenol ; ipsdienol ; traps
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In field experiments in Sweden, the constituent 2-methyl-3-buten-2-ol of the aggregation pheromone of the spruce bark bettleIps typographus (L.) was effectively replaced by 2-methyl-3-butyn-2-ol.
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  • 89
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    Journal of chemical ecology 13 (1987), S. 1591-1599 
    ISSN: 1573-1561
    Keywords: Gallery initiation ; host volatiles ; monoterpenes ; ethanol ; reproductive success ; bark beetle ; pine shoot beetle ; Tomicus piniperda ; Coleoptera ; Scolytidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In a trapping experiment, wood chips from freshly cut Scots pine trees attracted flying adults of the bark beetleTomicus piniperda (L.) Healthy Scots pine trees, which usually are not attacked byT. piniperda, were baited with chips from freshly cut trees. In other experiments trees were baited with a mixture of (−)-α-pinene, (+)-3-carene, and terpinolene; the individual monoterpenes; or with ethanol alone. All baited treatments were attacked byT. piniperda. Most of the attacks resulted in short egg galleries and in larval galleries which were only a few millimeters in length. In trees from which a new generation of beetles emerged, net reproduction was well below 1.0. Unbaited control trees remained unattacked or received a few isolated attacks.
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  • 90
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    Journal of chemical ecology 13 (1987), S. 1759-1770 
    ISSN: 1573-1561
    Keywords: Castanospermine ; 6-epicastanospermine ; deoxynojirimycin ; cellobiase ; lactase ; maltase ; sucrase ; trehalase ; endosymbiote ; insect-plant interactions ; allelochemicals ; Homoptera ; Coleoptera ; Lepidoptera ; Diptera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The indolizidine alkaloid, castanospermine (1,6,7,8-tetrahydroxy-octahydroindolizidine—a stereochemical mimic of glucose found in the Australian legumeCastanospermum australe), differentially inhibited cellobiose, lactose, maltose, sucrose, and trehalose hydrolyzing enzymes from a broad taxonomic spectrum of insects (19 species from 12 different families). It was a potent inhibitor of cellobiase activity of all insects tested (50% inhibition at 〈3.2 × 10−5 M castanospermine). With one exception, it also inhibited lactase activity of all insects examined. Only in the sap-feeding Homoptera did castanospermine inhibit all disaccharidase activities assayed. Trehalase activity of the Lepidoptera and Diptera was generally inhibited by castanospermine, whereas inhibition of trehalase activity of the Coleoptera by castanospermine was exiguous or not detectable. Castanospermine was a significant feeding deterrent towards pea aphids,Acyrthosiphon pisum, with an ED50 of 1 × 10−4 M in artificial diets. Two compounds stereochemically related to castanospermine, deoxynojirimycin and 6-epicastanospermine, were each slightly active at deterring the feeding of green peach aphids,Myzus persicae, (ED50=2.5 × 10−3 M) and greenbugs,Schizaphis graminum (ED50=5 × 10−3 M), respectively. Among the insects studied there was no distinct relationship between enzyme inhibition and adaptation to host plants containing castanospermine or other toxic alkaloids.
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  • 91
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    Journal of chemical ecology 13 (1987), S. 1833-1841 
    ISSN: 1573-1561
    Keywords: Plum curculio ; Conotrachelus nenuphar (Herbst) ; Coleoptera ; Curculionidae ; oviposition ; host discrimination ; host location
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Larval survival of plum curculios (PCs),Conotrachelus nenuphar (Herbst), was found to decrease with increasing egg density per fruit. Subsequently, we assayed PCs for propensity to avoid egg-laying at sites (immature plums) already occupied by conspecific eggs. Laboratory choice tests showed PCs made an equal number of visits to and ovipositions in fruit with a single oviposition as in clean fruit. Although there was a trend toward more visits to fruit which contained four or eight oviposition wounds and eggs or eight artificial punctures than to clean fruit, PCs oviposited less frequently into these than clean fruit. Results suggest that wounding of fruit may enhance the ability of ovipositing PCs to locate fruit, but at the same time may furnish cues allowing some degree of discrimination against heavily infested fruit for oviposition.
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  • 92
    ISSN: 1573-1561
    Keywords: Sex pheromone ; drugstore beetle ; Coleoptera ; Anobiidae ; Stegobium paniceum L. ; stegobinone ; diastereoisomer inhibition ; pheromonal activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Stegobinone, (2S, 3R, 1′R)-2,3,-dihy dro-2,3,5-trimethyl-6-(1′-methyl-2′-oxobutyl)-4H-pyran-4-one, the sex pheromone of drugstore beetles (Stegobium paniceum L.), elicited the pheromonal response from the males of the species in our bioassay system; however, the synthesized diastereomeric mixture of this compound was actually inactive to the males. Although the stegobinone isolated from the beetles of this species had significant activity, its enantiomeric [(±)-2S,3R,1′S-] and diatereomeric [(±)-2S,3S,1′RS-] isomers were inactive. Adding the (±)-2S,3R,1′S isomer to stegobinone significantly reduced the male response. Furthermore, the activity of Stegobinone vanished on keeping it at room temperature for two weeks. In such a stored stegobinone sample, the presence of 2S,3R,1′S isomer, the inhibitory component, was confirmed. This isomer might be produced by C-1′ epimerization during storage.
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  • 93
    ISSN: 1573-1561
    Keywords: Chiral semiochemicals ; pheromones ; enantiomeric composition ; enantiomeric synergism ; Cryptolestes ferrugineux ; Cryptolestes pusillus ; Cryptolestes turcicus ; Oryzaephilus mercator ; Oryzaephilus surinamensis ; Coleoptera ; Cucujidae ; (Z)-3-dodecen-11-olide ; (Z,Z)-3,6-dodecadien 11-olide ; (Z)-5-tetradecen-13-olide ; (Z,Z)-5,8-tetradecadien-13-olide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The chiralities of macrolide lactone aggregation pheromones of five species of economically important grain beetles have been determined by capillary gas chromatographic separation of the diastereomeric (S)-O-acetyllactate derivatives of the hydroxy methyl esters derived from boron trifluoride-catalyzed cleavage of the macrolides in methanol. Chirally pure (Z)-3-dodecen-11-olide (I) is produced in theS configuration byCryptolestes ferrugineus (Stephens) and in theR configuration byOryzaephilus mercator (Fauvel). (Z,Z)-3,6-Dodecadien-11-olide (II) is produced in theR configuration by bothO. mercator andO. surinamensis (L.). (Z,Z)-5,8-Tetradecadien-13-olide (IV) is produced in theR configuration byO. surinamensis and as a 85∶15 mixture ofR andS isomers byC. turcicus. (Z)-5-Tetradecen-13-olide (V) is produced in the S configuration byC. pusillus (Schönherr) and as a 33∶67 mixture of theR andS isomers byC. turcicus (Grouvelle). The results indicate that in these cucujids, species specificity in pheromone response is maintained at least in part by pheromone chirality.
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  • 94
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    Journal of chemical ecology 13 (1987), S. 1725-1738 
    ISSN: 1573-1561
    Keywords: Grandisal ; rearrangement ; isomerization ; acid catalysis ; silica gel catalysis ; Pissodes spp ; Coleoptera ; Curculionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Attempted purification of synthetic racemic grandisal1 by silica gel chromatography resulted in severe decomposition. The nature of this reaction was studied on silica gel and in an ether solution ofp-toluenesulfonic acid. The same products resulted from both reaction systems, although in different ratios. Five racemic, rearrangement products were isolated by preparative GC and identified as follows: (1RS, 3SR, 6RS)-1-methyl-5-methylenebicyclo[4.2.0]octan-3-ol (4); (1RS, 3RS, 6RS)-1-methyl-5-methylenebicyclo[4.2.0]octan-3-ol (5); (1RS,3RS,6RS)-1,5-dimethylbicyclo[4.2.0]oct-4-en-3-ol (6); (1RS,3SR,6RS)-1,5-dimethylbicyclo[4.2.0]oct-4-en-3-ol(7); and 3-methyl-7-methylenecyclooct-3-en-l-ol (8). The stereochemical assignments are based on our proposed mechanism, which also accounts for all products observed. The racemic bicyclic enone (3) was a by-product of grandisol (2) oxidation.
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