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991.
Kuipers OP de Jong A Baerends RJ van Hijum SA Zomer AL Karsens HA den Hengst CD Kramer NE Buist G Kok J 《Antonie van Leeuwenhoek》2002,82(1-4):113-122
992.
Kerwin JL Turecek F Xu R Kramer KJ Hopkins TL Gatlin CL Yates JR 《Analytical biochemistry》1999,268(2):229-237
Adducts of catechols and histidine, which are produced by reactions of 1,2-quinones and p-quinone methides with histidyl residues in proteins incorporated into the insect exoskeleton, were characterized using electrospray ionization mass spectrometry (ESMS), tandem electrospray mass spectrometry (ESMS-MS, collision-induced dissociation), and ion trap mass spectrometry (ITMS). Compounds examined included adducts obtained from acid hydrolysates of Manduca sexta (tobacco hornworm) pupal cuticle exuviae and products obtained from model reactions under defined conditions. The ESMS and ITMS spectra of 6-(N-3')-histidyldopamine [6-(N-3')-His-DA, pi isomer] isolated from M. sexta cuticle were dominated by a [M + H]+ ion at m/z 308, rather than the expected m/z 307. High-resolution fast atom bombardment MS yielded an empirical formula of C14H18N3O5, which was consistent with this compound being 6-(N-1')-histidyl-2-(3, 4-dihydroxyphenyl)ethanol [6-(N-1')-His-DOPET] instead of a DA adduct. Similar results were obtained when histidyl-catechol compounds linked at C-7 of the catechol were examined; the (N-1') isomer was confirmed as a DA adduct, and the (N-3') isomer identified as an (N-1')-DOPET derivative. Direct MS analysis of unfractionated cuticle hydrolysate revealed intense parent and product ions characteristic of 6- and 7-linked adducts of histidine and DOPET. Mass spectrometric analysis of model adducts synthesized by electrochemical oxidative coupling of N-acetyldopamine (NADA) quinone and N-acetylhistidine (NAcH) identified the point of attachment in the two isomers. A prominent product ion corresponding to loss of CO2 from [M + H]+ of 2-NAcH-NADA confirmed this as being the (N-3') isomer. Loss of (H2O + CO) from 6-NAcH-NADA suggested that this adduct was the (N-1') isomer. The results support the hypothesis that insect cuticle sclerotization involves the formation of C-N cross-links between histidine residues in cuticular proteins, and both ring and side-chain carbons of three catechols: NADA, N-beta-alanyldopamine, and DOPET. 相似文献
993.
Milk processing leads to severe protein damage caused by the formation of nonenzymatic posttranslational modifications (nePTMs), such as glycation and glycoxidation. As a result, the technological and nutritional function of milk proteins can be critically altered. The present study investigated the protein-specific distribution of the glycoxidation product N(ε) -carboxymethyllysine (CML) in the proteome of processed milk. For this purpose, raw milk and heated milk were separated by 1-D or 2-DE. The distribution of CML in the milk proteome was examined by immunoblotting. The changes in the protein composition that occurred during heating were monitored by Coomassie staining. Relative modification rates were measured for the major milk protein fractions after 30 and 60 min of heating at 120°C and normalized to the content of the respective protein fraction in the samples. The highest glycoxidation rates were detected in the high molecular weight aggregates that are generated during heating. The casein fraction and the whey protein β-lactoglobulin were affected in a similar manner. The relevance of the results for industrial milk processing was confirmed by analyzing several commercial milk products accordingly. The presented approach allows nonenzymatic posttranslational modification mapping of the entire milk proteome. 相似文献
994.
Merzendorfer H Kim HS Chaudhari SS Kumari M Specht CA Butcher S Brown SJ Manak JR Beeman RW Kramer KJ Muthukrishnan S 《Insect biochemistry and molecular biology》2012,42(4):264-276
Several benzoylphenyl urea-derived insecticides such as diflubenzuron (DFB, Dimilin) are in wide use to control various insect pests. Although this class of compounds is known to disrupt molting and to affect chitin content, their precise mode of action is still not understood. To gain a broader insight into the mechanism underlying the insecticidal effects of benzoylphenyl urea compounds, we conducted a comprehensive study with the model beetle species and stored product pest Tribolium castaneum (red flour beetle) utilizing genomic and proteomic approaches. DFB was added to a wheat flour-based diet at various concentrations and fed to larvae and adults. We observed abortive molting, hatching defects and reduced chitin amounts in the larval cuticle, the peritrophic matrix and eggs. Electron microscopic examination of the larval cuticle revealed major structural changes and a loss of lamellate structure of the procuticle. We used a genomic tiling array for determining relative expression levels of about 11,000 genes predicted by the GLEAN algorithm. About 6% of all predicted genes were more than 2-fold up- or down-regulated in response to DFB treatment. Genes encoding enzymes involved in chitin metabolism were unexpectedly unaffected, but many genes encoding cuticle proteins were affected. In addition, several genes presumably involved in detoxification pathways were up-regulated. Comparative 2D gel electrophoresis of proteins extracted from the midgut revealed 388 protein spots, of which 7% were significantly affected in their levels by DFB treatment as determined by laser densitometry. Mass spectrometric identification revealed that UDP-N-acetylglucosamine pyrophosphorylase and glutathione synthetase were up-regulated. In summary, the red flour beetle turned out to be a good model organism for investigating the global effects of bioactive materials such as insect growth regulators and other insecticides. The results of this study recapitulate all of the different DFB-induced symptoms in a single model insect, which have been previously found in several different insect species, and further illustrate that DFB treatment causes a wide range of effects at the molecular level. 相似文献
995.
Mikkel Winther Pedersen Bianca De Sanctis Nedda F. Saremi Martin Sikora Emily E. Puckett Zhenquan Gu Katherine L. Moon Joshua D. Kapp Lasse Vinner Zaruhi Vardanyan Ciprian F. Ardelean Joaquin Arroyo-Cabrales James A. Cahill Peter D. Heintzman Grant Zazula Ross D.E. MacPhee Beth Shapiro Richard Durbin Eske Willerslev 《Current biology : CB》2021,31(12):2728-2736.e8
996.
B M Kacinski D Carter E I Kohorn K Mittal R S Bloodgood J Donahue C A Kramer D Fischer R Edwards S K Chambers 《The Yale journal of biology and medicine》1989,62(4):379-392
Six-micron paraffin sections of paraformaldehyde-fixed specimens of 24 ovarian benign and neoplastic specimens were assayed for tumor cell-specific oncogene expression by a sensitive, quantitative in situ hybridization technique with probes for 17 oncogenes, beta-actin, and E. coli beta-lactamase. In the benign, borderline, and invasive adenocarcinomas, multiple oncogenes, including neu, fes, fms, Ha-ras, trk, c-myc, fos, and PDGF-A chains, were expressed at significant levels relative to a housekeeping gene (beta-actin). In the mixed-Mullerian tumors, a rather different pattern of oncogene expression was observed, characterized primarily by expression of sis (PDGF-B chain). For the adenocarcinomas, statistical analysis demonstrated that expression of several genes (fms, neu, PDGF-A) was closely linked to others (c-fos, c-myc) known to have important roles in the control of cell proliferation, but only one gene, fms, correlated very strongly with clinicopathologic features (high FIGO histologic grade and high FIGO clinical stage) predictive of aggressive clinical behavior and poor outcome. The authors discuss the role that tumor epithelial cell expression of the fms gene product might play in the auto- and paracrine control of growth and dissemination of ovarian adenocarcinomas. 相似文献
997.
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1000.
Gustav Kramer und Ursula von St. Paul 《Journal of Ornithology》1956,97(4):371-376
Zusammenfassung 21 Tauben, die seit dem halbflüggen Zustand ihr Leben in einer geräumigen Voliere verbracht hatten, wurden in einer Entfernung von 22 km vom Heimatort einzeln aufgelassen. 5 Tauben waren am Auflaßtag zurück, 6 am Tag danach, 3 noch einen Tag später, eine kam nach 10 Tagen, 6 blieben aus. Eine der 6 ausgebliebenen wurde auf der Strecke gefunden (Abb. 2). Dieses Ergebnis liefert schon für sich allein einen starken Hinweis auf gerichtetes Heimfinden, das nicht durch Landschaftskenntnis erklärt werden kann.Die Beweiskraft der Heimkehrergebnisse wird zwingend, wenn sie mit dem Heimkehrerfolg von im Winter aufgelassenen, frei gehaltenen Erstfliegern auf derselben Strecke verglichen werden. Letztere mußten über weit bessere Geländekenntnisse verfügen als die Käfigtauben, außerdem sind sie physisch überlegen. Tatsächlich ist jedoch ihr Heimkehrerfolg geringer.Von 8 Käfigtauben, die aus 2,8 km aufgelassen wurden, kehrte eine einzige stracks zum Käfig zurück, obwohl sie ihn auf dem der Beobachtung zugänglichen Teil der Strecke gar nicht sehen konnte. Die übrigen 7 flogen zögernd und stark streuend ab, jedoch kehrten 6 binnen 1 bis 6 Stunden zum Käfig zurück, die siebente ging verloren. Das Gelände, von dem aufgelassen wurde, konnte von den Tauben während ihres Käfigdaseins nicht eingesehen werden, da ein Deich, höher als der Käfig, dazwischen lag.Dieser Versuch zeigt vor allem, daß Käfigtauben nicht imstande sind, aus 2,8 km ihren Käfig mittels des Gesichtssinnes zu identifizieren.Der quantitative Vergleich mit den Heimkehrergebnissen der aus 2,8 km aufgelassenen Käfigtauben liefert die Handhabe zu einer weiteren Beweisführung dafür, daß die aus 22 km aufgelassenen Käfigtauben sich vorwiegend einer anderen Orientierungsmethode als die ersteren bedient haben mußten. 相似文献