Petroleum powered vehicles emit volatile organic compounds (VOCs) through combustion that contributes to the pollution of the environment. A technique in the 1970s was developed to decrease these emissions, especially for nitrogen oxides (NOx) and sulphuric oxides (SOx) which is called exhaust gas recirculation (EGR). The technique works by recirculating a portion of the combusted gas back into the engine, this limits the NOx and SOx emissions because of lower temperatures and less available oxygen. The problems that follow these effects is the formation and condensation of acids that corrode the material of the EGR system, which are created by many different reactions. It is of importance to understand how the compounds in the EGR system behaves through analysis of authentic and simulated condensates, which is why a quantitative method for these compounds are of interest. The aim of the project was to develop a simple quantitative analysis method for formic acid, acetic acid, and lactic acid in aqueous solution, which was done at Gränges Sweden AB. The technique used for detection and quantification was gas chromatography (GC) coupled to a flame ionization detector (FID) and a water compatible polyethylene glycol (PEG) column. Fractional factorial design (FFD) was used for determination of adequate operating parameters of the GC method and the sample preparation. Sample preparation only required filtration and pH adjustment prior to direct aqueous injection (DAI) to the chromatographic instrument. Detection of the analytes was very difficult because of non-compatibility with the FID, and quantification of asymmetric peak shapes made this problem worse, omitting lactic acid from further analysis. Limit of detection (LOD) and limit of quantification (LOQ) was 490 and 1640 ppm for formic acid and 120 and 400 ppm for acetic acid, with an injection volume of 0.3 μL and split ratio 10:1. Limits were too high for every EGR sample leaving no peaks detected for the sample preparation used. Further development should be done with complementary techniques and sample reprocessing in order to quantify the compounds.

In der Hefe Yarrowia lipolytica führen Mutationen im GPR1-Gen zu Essigsäuresensitivität. Die Deletion dieses Genes hat demgegenüber keinen Effekt auf den Phänotyp. In dieser Arbeit wurde das Gpr1-Protein näher charakterisiert. Es zeigte sich, dass GPR1-Mutantenstämme wesentlich schneller Acetat akkumulierten als der Wildtyp. Außerdem konnte bestetigt werden, dass Gpr1p ein integrales Membranprotein ist. Mittels Ortspezifischer Analyse wurden verschiedene funktionelle Bereiche untersucht. Das Protein unterliegt zudem einer Phosphorylierung/Dephosphorylierung. Auf der Grundlage der dargelegten Ergebnisse wurde ein Funktionsmodell für Gpr1p erstellt.

<p> Dimethylgermylene (GeMe2) has been generated by laser flash photolysis of 1,1dimethyl-3-phenylgermacyclopent-3-ene (23) and 1,1,3-trimethyl-4phenylgermacyclopent-3-ene (24) in hexanes at 25°C and its absorption maximum (λmax) has been unambiguously established to be 470 nm. GeMe2 decays with second-order kinetics under these conditions (2k/ε. = (10 ± 2) x 10^7 cm s^(-1)) to give Ge2Me4 (λmax = 370 nm). Kinetic studies of the reactions of GeMe2 and Ge2Me4 with typical germylene/digermene scavengers such as 1,3-dienes, olefins, alkynes, alkyl halides, group 14 metal hydrides, carboxylic acids, and amines have been carried out. </p> <p> GeMe2 reacts reversibly with MeOH, t-BuOH and THF to form Lewis acid-base complexes which exhibit relatively strong absorption bands that are blue-shifted with respect to GeMe2 (λmax ~ 295-310 nm). The decay of the Me2Ge-MeOH complex is accelerated in the presence of a Brnnsted acid (acetic acid or methanesulfonic acid) or base (MeONa). The reactions of the Me2Ge-THF complex with sodium methoxide, methanesulfonic acid, 4,4-dimethyl-1-pentene, 2,3-dimethyl-1-butadiene, acetic acid and CC4 have also been studied in THF. </p> <p> The photochemistry of two well-known precursors to GeMe2, namely dodecamethylcyclohexagermane (14) and dimethylphenyl(trimethylsilyl)germane (18) was reinvestigated. Laser flash photolysis of 14 in hexanes led to the formation of two transients, one with λmax= 490 nm (τ < & = 10 ns) and the second with λmax= 470 nm. The latter decays with second-order kinetics with concomitant formation of a new transient with λmax= 370 nm. The transient at 470 nm is assigned to GeMe2 and that at 370 nm to Ge2Me4, based on comparisons to the results obtained from laser flash photolysis of 23 and 24. Laser flash photolysis of 18-in hexane gives rise to two absorption bands centered at λmax = 300 nm and λmax = 430 nm, which are assigned to the dimethylphenylgerrnyl radical and the conjugated gerrnene derivative 38, respectively. GeMe2 cannot be detected in laser flash photolysis experiments with this compound. </p> / Thesis / Doctor of Philosophy (PhD)

No / A systematic identification of the degradation products of hydroxypropyl methylcellulose phthalate (HPMCP) during hot melt extrusion (HME) has been performed. A reverse phase HPLC method was developed for the extrudates of both hydroxypropyl methylcellulose acetate succinate (HPMCAS) and HPMCP polymers to quantify their thermal hydrolytic products: acetic acid (AA), succinic acid (SA) for HPMCAS and phthalic acid (PA) for HPMCP, without hydrolysing the polymers in strong alkaline solutions. The polymers were extruded in the temperature range of 160-190 degrees C at different screw rotation speeds and hydrolytic impurities were analysed. Investigation of extruded HPMCP showed an additional thermal degradation product, who is structural elucidation revealed to be phthalic anhydride (PAH). Moreover, two environmental analytical impurities, dimethyl phthalate and methyl benzoate formed in situ were recorded on GC-MS and their origin was found to be associated with PAH derivatization. Using the experimental data gathered during this study, a degradation mechanism for HPMCP is proposed.

No description available.

Esôfago de Barrett é definido como a substituição do epitélio escamoso normal por epitélio colunar com metaplasia intestinal especializada (MIE), tendo como causa a persistência do refluxo gastro-esofágico. Seu diagnóstico é baseado na identificação endoscópica e na confirmação histológica da presença de MIE. Esôfago de Barrett é a principal causa do desenvolvimento do adenocarcinoma esofágico. Aos pacientes com esôfago de Barrett é recomendada vigilância endoscópica com biópsias seriadas tentando-se diagnosticar, precocemente, lesões precursoras ou o adenocarcinoma em estágio precoce e factível de resposta à terapia. O aumento da incidência do adenocarcinoma tem contribuído para o estudo de novas técnicas endoscópicas visando melhorar a detecção destas lesões. Este estudo foi realizado objetivando-se avaliar a eficácia da cromoscopia com azul de metileno, associada a magnificação de imagem com ácido acético, na detecção de MIE, displasia e adenocarcinoma. Prospectivamente, 35 pacientes com diagnóstico de esôfago de Barrett em acompanhamento ambulatorial, com extensão superior a 2,0 cm, realizaram dois exames de endoscopia digestiva alta, sendo um convencional com biópsias seriadas e um segundo com aplicação de azul de metileno, seguida do ácido acético, magnificação de imagem e biópsias. Realizaram-se biópsias adicionais de qualquer alteração do relevo mucoso. A freqüência diagnóstica da metaplasia intestinal especializada foi de 71,4% e 77,1% para biópsias orientadas pelo método convencional e pelo método da cromoscopia/magnificação de imagem, respectivamente (p=0,41). Freqüência de displasia ou adenocarcinoma foi de 9% para as biópsias orientadas pelo método convencional e 6% para biópsias orientadas pela cromoscopia/magnifcação de imagem. Tanto os pacientes com displasia de alto grau quanto aqueles com adenocarcinoma apresentaram alterações em sua superfície mucosa visíveis em ambos os métodos endoscópicos. A sensibilidade e a especificidade da cromoscopia, quando avaliamos as áreas coradas em detectar MIE foi de 88% e 50%, respectivamente. A sensibilidade e a especificidade das áreas não coradas em detectar displasia e/ou adenocarcinoma foi de 75% e 100%, respectivamente. A sensibilidade e a especificidade da magnificação de imagem, quando avaliamos as áreas com padrão viliforme em detectar MIE foi 88% e 50%, respectivamente. Tanto a sensibilidade quanto a especificidade das áreas com padrão amorfo em detectar displasia e/ou adenocarcinoma foi de 100%. A sensibilidade e a especificidade da cromoscopia/magnificação de imagem, para padrão corado e viliforme, em detectar MIE foi de 83% e 50%, respectivamente. Já a sensibilidade e a especificidade das áreas não coradas e com padrão amorfo em detectar displasia e/ou adenocarcinoma teve seu cálculo prejudicado pela pequena amostra estudada. Na comparação dos dois métodos empregados, verificaram-se resultados similares na detecção de metaplasia intestinal, displasia e câncer. A realização de cromoscopia/magnificação de imagem proporcionou: alta sensibilidade e baixa especificidade na detecção da metaplasia intestinal especializada e baixa sensibilidade e alta especificidade na detecção de displasia ou adenocarcinoma. Alterações da superfície mucosa corresponderam as áreas neoplásicas. / Barrett\'s esophagus is defined as the replacement of the normal squamous epithelium by columnar lined esophagus. The diagnosis requires endoscopically visible columnar lined esophagus and histologic identification of characteristic specialized intestinal-type metaplasia (SIM). Gastroesophageal reflux has been proposed as a risk factor for Barrett`s esophagus and this disease has been shown to be the main cause of esophageal adenocarcinoma. After the diagnosis of Barrett`s esophagus, endoscopy surveillance is recommended with multiple biopsies of the columnar lined esophagus at quadrants of 2 cm intervals to determine epithelial dysplasia or adenocarcinoma in early and curable stage. Due to the increase in the incidence of esophageal adenocarcinoma new techniques of endoscopic surveillance have been proposed. The aim of this study was to evaluate the efficacy of magnification chromoendoscopy with methylene blue and acetic acid for the detection of intestinal metaplasia, dysplasia and cancer. Prospectively, 35 patients with Barrett\'s esophagus extending for more than 2,0 cm, underwent two upper digestive endoscopy procedures, including one with conventional biopsies and other with chromoendoscopy using methylene blue and acetic acid instillation, magnification and biopsies. Biopsies were also taken from any suspicious mucosal area. The incidence of MIE were 71,4% e 77,1% from conventional biopsies and chromoendoscopy/magnification, respectively. Dysplasia and adenocarcinoma were diagnosed in 9% and 6% throught conventional biopsies and chromoendoscopy/magnification, respectively. Patients with high grade dysplasia or adenocarcinoma revealed mucosal alterations. The sensitivity and specificity rates for chromoendoscopy for stained areas for MIE were 88% and 50%, respectively. The sensitivity and specificity rates for non stained areas for dysplasia and cancer were 75% and 100%, respectively. The sensitivity and specificity rates for magnification for villous areas for MIE were 88% and 50%, respectively. The sensitivity and specificity rates for distorted areas for dysplasia and cancer were 100%. The sensitivity and specificity rates for chromoendoscopy/magnification (for stained and villous areas) for MIE were 83% and 50%, respectively. The sensitivity and specificity rates for non stained and distorted areas couldn?t be evaluated due to the small number of patients. In conclusion, results of the two methods were similar in detecting intestinal metaplasia, dysplasia and cancer. The chromoendoscopy/magnification method procedure provides high sensitivity and low specificity rates in detecting MIE and low sensitivity and high specificity rates in detecting dysplasia and adenocarcinoma. Alterations in the mucosa corresponded to cancer and dysplasia.

<p>Predmet ovog istaživanja&nbsp; bio je ispitivanje&nbsp;uticaja jona tri te&scaron;ka metala (Ni²⁺, Cu^2+&nbsp;i Cd²⁺)&nbsp;u dve toksične koncentracije u zemlji&scaron;tu na&nbsp;fiziolo&scaron;ke i biohemijske karakteristike&nbsp;<br />odabranih klonova topola, M1, B229 i Pe 19/66.&nbsp;Ispitan je i potencijal odabranih klonova topola&nbsp;da vr&scaron;e fitoekstrakciju-akumulaciju te&scaron;kih&nbsp;metala iz zemlji&scaron;ta u svoje nadzemne delove &scaron;to&nbsp;dovodi&nbsp; do dugoročnog uklanjanja ovih&nbsp;perzistentnih polutanata iz životne sredine.&nbsp;Takođe, ispitan je uticaj te&scaron;kih metala na&nbsp;antioksidantni potencijal, sposobnost&nbsp;<br />neutalizacije slobodnih radikala, aktivnosti&nbsp;antioksidantih enzima kao i&nbsp; na sadržaj&nbsp;slobodnih i konjugovanih poliamina (Put, Spm,&nbsp;Spd),&nbsp; određenih HPLC analizom,&nbsp; i sadržaj&nbsp;biljnih hormona poput indol-3-sirćetne kiseline&nbsp;i&nbsp; abscisinske &nbsp;kiseline,&nbsp; određenih GC/MS&nbsp;analizom, u listovima i korenovima klonova topola.</p><p>&nbsp;</p> / <p>The aim of this study was to estimate and compare phytoextraction capacities of three&nbsp;poplar clones (M1, B229 and Pe 19/66) in soil. Furthermore, the goal was to assess &nbsp;different biological responses among the poplar clones during exposure to different concentration of three heavy metal ions (Ni²⁺, Cu²⁺ i Cd²⁺). In order to track changes in&nbsp; poplars&rsquo;mineral, physiological, biochemical and antioxidant status during the&nbsp; abiotic stress, quantification of physiological properties, free and conjugated polyamines, total phenolics&nbsp; as well as quantification of phytohormones (indol-3-acetic and abscisic acid) was done. Furthermore, assessment of antioxidant potential by tracking radical scavenger capacities (RSC) against DPPH, ABTS, OH and NO radicals and by measuring enzymes activities (SOD, GSH-Px, GPx, GR) in vitro was performed in root and leaves of poplar clones.</p>

Esôfago de Barrett é definido como a substituição do epitélio escamoso normal por epitélio colunar com metaplasia intestinal especializada (MIE), tendo como causa a persistência do refluxo gastro-esofágico. Seu diagnóstico é baseado na identificação endoscópica e na confirmação histológica da presença de MIE. Esôfago de Barrett é a principal causa do desenvolvimento do adenocarcinoma esofágico. Aos pacientes com esôfago de Barrett é recomendada vigilância endoscópica com biópsias seriadas tentando-se diagnosticar, precocemente, lesões precursoras ou o adenocarcinoma em estágio precoce e factível de resposta à terapia. O aumento da incidência do adenocarcinoma tem contribuído para o estudo de novas técnicas endoscópicas visando melhorar a detecção destas lesões. Este estudo foi realizado objetivando-se avaliar a eficácia da cromoscopia com azul de metileno, associada a magnificação de imagem com ácido acético, na detecção de MIE, displasia e adenocarcinoma. Prospectivamente, 35 pacientes com diagnóstico de esôfago de Barrett em acompanhamento ambulatorial, com extensão superior a 2,0 cm, realizaram dois exames de endoscopia digestiva alta, sendo um convencional com biópsias seriadas e um segundo com aplicação de azul de metileno, seguida do ácido acético, magnificação de imagem e biópsias. Realizaram-se biópsias adicionais de qualquer alteração do relevo mucoso. A freqüência diagnóstica da metaplasia intestinal especializada foi de 71,4% e 77,1% para biópsias orientadas pelo método convencional e pelo método da cromoscopia/magnificação de imagem, respectivamente (p=0,41). Freqüência de displasia ou adenocarcinoma foi de 9% para as biópsias orientadas pelo método convencional e 6% para biópsias orientadas pela cromoscopia/magnifcação de imagem. Tanto os pacientes com displasia de alto grau quanto aqueles com adenocarcinoma apresentaram alterações em sua superfície mucosa visíveis em ambos os métodos endoscópicos. A sensibilidade e a especificidade da cromoscopia, quando avaliamos as áreas coradas em detectar MIE foi de 88% e 50%, respectivamente. A sensibilidade e a especificidade das áreas não coradas em detectar displasia e/ou adenocarcinoma foi de 75% e 100%, respectivamente. A sensibilidade e a especificidade da magnificação de imagem, quando avaliamos as áreas com padrão viliforme em detectar MIE foi 88% e 50%, respectivamente. Tanto a sensibilidade quanto a especificidade das áreas com padrão amorfo em detectar displasia e/ou adenocarcinoma foi de 100%. A sensibilidade e a especificidade da cromoscopia/magnificação de imagem, para padrão corado e viliforme, em detectar MIE foi de 83% e 50%, respectivamente. Já a sensibilidade e a especificidade das áreas não coradas e com padrão amorfo em detectar displasia e/ou adenocarcinoma teve seu cálculo prejudicado pela pequena amostra estudada. Na comparação dos dois métodos empregados, verificaram-se resultados similares na detecção de metaplasia intestinal, displasia e câncer. A realização de cromoscopia/magnificação de imagem proporcionou: alta sensibilidade e baixa especificidade na detecção da metaplasia intestinal especializada e baixa sensibilidade e alta especificidade na detecção de displasia ou adenocarcinoma. Alterações da superfície mucosa corresponderam as áreas neoplásicas. / Barrett\'s esophagus is defined as the replacement of the normal squamous epithelium by columnar lined esophagus. The diagnosis requires endoscopically visible columnar lined esophagus and histologic identification of characteristic specialized intestinal-type metaplasia (SIM). Gastroesophageal reflux has been proposed as a risk factor for Barrett`s esophagus and this disease has been shown to be the main cause of esophageal adenocarcinoma. After the diagnosis of Barrett`s esophagus, endoscopy surveillance is recommended with multiple biopsies of the columnar lined esophagus at quadrants of 2 cm intervals to determine epithelial dysplasia or adenocarcinoma in early and curable stage. Due to the increase in the incidence of esophageal adenocarcinoma new techniques of endoscopic surveillance have been proposed. The aim of this study was to evaluate the efficacy of magnification chromoendoscopy with methylene blue and acetic acid for the detection of intestinal metaplasia, dysplasia and cancer. Prospectively, 35 patients with Barrett\'s esophagus extending for more than 2,0 cm, underwent two upper digestive endoscopy procedures, including one with conventional biopsies and other with chromoendoscopy using methylene blue and acetic acid instillation, magnification and biopsies. Biopsies were also taken from any suspicious mucosal area. The incidence of MIE were 71,4% e 77,1% from conventional biopsies and chromoendoscopy/magnification, respectively. Dysplasia and adenocarcinoma were diagnosed in 9% and 6% throught conventional biopsies and chromoendoscopy/magnification, respectively. Patients with high grade dysplasia or adenocarcinoma revealed mucosal alterations. The sensitivity and specificity rates for chromoendoscopy for stained areas for MIE were 88% and 50%, respectively. The sensitivity and specificity rates for non stained areas for dysplasia and cancer were 75% and 100%, respectively. The sensitivity and specificity rates for magnification for villous areas for MIE were 88% and 50%, respectively. The sensitivity and specificity rates for distorted areas for dysplasia and cancer were 100%. The sensitivity and specificity rates for chromoendoscopy/magnification (for stained and villous areas) for MIE were 83% and 50%, respectively. The sensitivity and specificity rates for non stained and distorted areas couldn?t be evaluated due to the small number of patients. In conclusion, results of the two methods were similar in detecting intestinal metaplasia, dysplasia and cancer. The chromoendoscopy/magnification method procedure provides high sensitivity and low specificity rates in detecting MIE and low sensitivity and high specificity rates in detecting dysplasia and adenocarcinoma. Alterations in the mucosa corresponded to cancer and dysplasia.

Biologische Diversität existiert sowohl zwischen mehreren Arten als auch innerhalb einer Art, innerhalb von Populationen und Individuen einer Population. Die intraspezifische Diversität wurde bislang ausgiebig auf der Ebene des Genoms untersucht. Sie ist im Kontext metabolischer Zusammenhänge in Pflanzen bisher kaum untersucht und es existieren nur wenige Veröffentlichungen zu diesem Thema. Uns sind bisher keine Publikationen zu Phytohormonen in Sesam bekannt. Neben dem wissenschaftlichen Interesse an der metabolischen Diversität in Sesam, spielen Stresshormone eine wichtige Rolle in der pflanzlichen Abwehr. Der Phytohormonspiegel im Samen ist unter agronomischen Gesichtspunkten relevant, da es vorkommen kann, dass Sesamsamen spontan auskeimen, während sie sich noch an der grünen Pflanze befinden. Diese Eigenschaft ist unerwünscht, da der wertvolle Samen auf diese Weise verloren geht. Im Rahmen dieser Arbeit wurde die Variation im Phytohormonniveau in 16 Akzessionen mit unterschiedlicher geographischer Herkunft untersucht. In Blättern und Wurzeln konnten ABA, JA, SA und SAG nachgewiesen werden, während GA4 lediglich in Blättern vorkam. Eine der Akzessionen aus Japan („Japan 2“) produzierte JA, SA und SAG in hohem Ausmaß. Hier konnten außerdem hohe Gehalte an Chitinasen festgestellt werden. Chitinasen sind für den Abbau von Chitin, dem Hauptbestandteil der pilzlichen Zellwand, verantwortlich. Eine Charakterisierung der Akzessionen mittels AFLP-Analyse zeigte, dass sich „Japan 2“ genetisch nicht mehr von anderen Akzessionen unterschied, als das Mittel der Unterschiede innerhalb aller gesammelten Proben. Bereits in früheren Untersuchungen unserer Arbeitsgruppe im Rahmen einer ungerichteten Metabolitenanalyse, konnte eine hohe Variabilität bei Sesamakzessionen gezeigt werden (Laurentin et al. 2006). Darüber hinaus, stimmen die Unterschiede im metabolischen Profil der Akzessionen nicht mit dem Grad ihrer genetischen Verwandtschaft überein. Es ist bekannt, dass tageszeitliche Unterschiede viele biologische Prozesse kontrollieren. Wir haben die tageszeitlichen Effekte auf den Phytohormonstatus untersucht und dabei die Unterschiede in Pflanzenorganen berücksichtigt. Tageszeitliche Konzentrationen von ABA, JA, IAA, SA und SAG wurden zu 8 unterschiedlichen Tageszeitpunkten in 3 unabhängigen Replikaten mittels HPLC untersucht. Wir konnten keine statistisch signifikanten Unterschiede erkennen. Die Untersuchungen zeigten jedoch eine Variation in den Phytohormonkonzentrationen in unterschiedlichen pflanzlichen Organen. Sekundäre pflanzliche Metabolite spielen als Resistenzfaktoren gegen Mikroorganismen eine wichtige Rolle. Sesamakzessionen, die diese Substanzen im hohen Ausmaß produzieren, stellen eine wichtige züchterische Ressource da. Um die Variation innerhalb der Akzessionen zu untersuchen, die ein hohes Niveau an sekundären Inhaltsstoffen aufweisen, haben wir die Effekte von 32 Pflanzenextrakten aus Sesamakzessionen gegen phytopathogene Pilze untersucht. Darunter befand sich ein Wurzelpathogen mit Spezialisierung auf Sesam (Macrophomina phaseolina), ein Blattpathogen mit breitem Wirtspflanzenkreis (Alternaria alternata) und Gefäßpathogen (Fusarium oxysporum). Die Diversität der Effekte, die für die unterschiedlichen Akzessionen beobachtet werden konnten, führt zu der Annahme, dass die Resistenzeigenschaften der Pflanzen durch gezielte züchterische Beeinflussung der metabolischen Aktivität verbessert werden können. In weiterführenden Untersuchungen zur Aufreinigung der Substanzen mit inhibitorischer Wirkung wurden Pflanzenextrakte in 80% Ethanol mit verschiedenen organischen Lösungsmitteln fraktioniert. Die meisten inhibitorischen Effekte konnten der Diethylether-Fraktion zugeschrieben werden. Im ersten Schritt wurden 4L des Extraktes hergestellt. Zwei aufgereinigte Lignane aus Sesam wurden gegen M. phaseolina, A. alternata und F. oxysporum getestet. Sesamin zeigte keinen Effekt bis zu einer Konzentration von 5mg/ml, während Sesamol (und 2,4-Dinitrophenol als Kontrolle) einen starken inhibitorischen Effekt aufwies. Für diese Substanzen wurden IC50 Werte ermittelt. Man kann festhalten, dass Sesamol dazu dienen kann, das Wachstum invasiver Pathogene einzuschränken. Durch die Kreuzung von zwei Elternlinien, die in der AFLP-Analyse einen signifikanten Polymorphismus aufwiesen, wurden Inzuchtlinien erzeugt. Die Nachkommen dieser Kreuzung wurden in 5 Generationen selbstbefruchtet. Das so entstandene Set aus RILs wurde mittels AFLP charakterisiert. Alle untersuchten RILs waren Hybride. Dies zeigt, dass während der ersten Kreuzung der Elternlinien keine Selbstung erfolgte. Wie erwartet, spalteten polymorphe AFLP-Marker der Elternlinien in den RILs zufällig auf. Monomorphe Marker fehlten in einigen RILs. Des Weiteren traten neue Marker auf, die zuvor nicht in den Elternlinien festgestellt werden konnten. Das Auftreten neuer Marker kann durch Rekombination zwischen Restriktionsfragmenten erklärt werden, welche die AFLP-Marker begrenzen. Die RILs werden nun von unseren Kooperationspartnern zum Aufbau einer genetischen Karte verwendet (Prof. Sami Doganlar und seine Arbeitsgruppe, Universität Antalya, Türkei).

<p><a></a><a></a><a></a><a></a><a></a><a></a><a></a><a></a><a></a><a></a><a>ABSTRACT</a></p> <p>Phenols are ubiquitous in our surroundings including biological molecules such as L-Dopa metabolites, food components, such as whiskey and liquid smoke, etc. This dissertation describes a new method for detecting phenols, by reaction with Gibbs reagent to form indophenols, followed by mass spectrometric detection. Unlike the standard Gibbs reaction which uses a colorimetric approach, the use of mass spectrometry allows for simultaneous detection of differently substituted phenols. The procedure is demonstrated to work for a large variety of phenols without <i>para</i>‐substitution. With <i>para</i>‐substituted phenols, Gibbs products are still often observed, but the specific product depends on the substituent. For <i>para</i> groups with high electronegativity, such as methoxy or halogens, the reaction proceeds by displacement of the substituent. For groups with lower electronegativity, such as amino or alkyl groups, Gibbs products are observed that retain the substituent, indicating that the reaction occurs at the <i>ortho</i> or <i>meta</i> position. In mixtures of phenols, the relative intensities of the Gibbs products are proportional to the relative concentrations, and concentrations as low as 1 μmol/L can be detected. The method is applied to the qualitative analysis of commercial liquid smoke, and it is found that hickory and mesquite flavors have significantly different phenolic composition.</p> <p>In the course of this study, we used this technique to quantify major phenol derivatives in commercial products such as liquid smoke (catechol, guaiacol and syringol) and whiskey (<i>o</i>-cresol, guaiacol and syringol) as the phenol derivatives are a significant part of the aroma of foodstuffs and alcoholic beverages. For instance, phenolic compounds are partly responsible for the taste, aroma and the smokiness in Liquid Smokes and Scotch whiskies. </p> <p>In the analysis of Liquid Smokes, we have carried out an analysis of phenols in commercial liquid smoke by using the reaction with Gibbs reagent followed by analysis using electrospray ionization mass spectrometry (ESI-MS). This analysis technique allows us to avoid any separation and/or solvent extraction steps before MS analysis. With this analysis, we are able to determine and compare the phenolic compositions of hickory, mesquite, pecan and apple wood flavors of liquid smoke. </p> <p>In the analysis of phenols in whiskey, we describe the detection of the Gibbs products from the phenols in four different commercial Scotch whiskies by using simple ESI-MS. In addition, by addition of an internal standard, 5,6,7,8-tetrahydro-1-napthol (THN), concentrations of the major phenols in the whiskies are readily obtained. With this analysis we are able to determine and compare the composition of phenols in them and their contribution in the taste, smokey, and aroma to the whiskies.</p> <p>Another important class of phenols are found in biological samples, such as L-Dopa and its metabolites, which are neurotransmitters and play important roles in living systems. In this work, we describe the detection of Gibbs products formed from these neurotransmitters after reaction with Gibbs reagent and analysis by using simple ESI‐MS. This technique would be an alternative method for the detection and simultaneous quantification of these neurotransmitters. </p> <p>Finally, in the course of this work, we found that the positive Gibbs tests are obtained for a wide range of <i>para</i>-substituted phenols, and that, in most cases, substitution occurs by displacement of the <i>para</i>-substituent. In addition, there is generally an additional unique second-phenol-addition product, which conveniently can be used from an analytical perspective to distinguish <i>para</i>-substituted phenols from the unsubstituted versions. In addition to using the methodology for phenol analysis, we are examining the mechanism of indophenol formation, particularly with the <i>para</i>-substituted phenols. </p> <p>The importance of peptides to the scientific world is enormous and, therefore, their structures, properties, and reactivity are exceptionally well-characterized by mass spectrometry and electrospray ionization. In the dipeptide work, we have used mass spectrometry to examine the dissociation of dipeptides of phenylalanine (Phe), containing sulfonated tag as a charge carrier (Phe*), proline (Pro) to investigate their gas phase dissociation. The presence of sulfonated tag (SO₃^-) on the Phe amino acid serves as the charge carrier such that the dipeptide backbone has a canonical structure and is not protonated. Phe-Pro dipeptide and their derivatives were synthesized and analyzed by LCQ-Deca mass spectroscopy to get the fragmentation mechanism. To confirm that fragmentation path, we also synthesized dikitopeparazines and oxazolines from all combinations of the dipeptides. All these analyses were confirmed by isotopic labeling experiments and determination and optimization of structures were carried out using theoretical calculation. We have found that the fragmentation of Phe*Pro and ProPhe* dipeptides form sequence specific b₂ ions. In addition, not only is the ‘mobile proton’ involved in the dissociation process, but also is the ‘backbone hydrogen’ is involved in forming b₂ ions. </p> <p> </p>