O complexo Mre11 (Mre11/Rad50/Nbs1) é uma componente chave da resposta celular ao dano ao DNA em humanos e recentes observações sugerem que estas proteínas são em parte responsáveis pela interface ente o ensoreamento do dano ao DNA, seu reparo e as funções das proteínas envolvidas nos pontos de checagem do ciclo celular. Em Aspergillus nidulans, a partir de um screening para o isolamento de letais sintéticos na ausência de dineína, o gene sldIRAD50 foi clonado como um desses letais sintéticos através da complementação do fenótipo de deficiência de conidiação do mutante. Foi identificada uma transversão G-C na posição 2509 (Ala-692-Pro) no mutante sldI1444 a qual está presente na região de dobradiça da proteína. Essa mutação causa sensibilidade a vários agentes mutagênicos. Uma linhagem mutante sldIRAD50::pyrG foi construída a qual apresentou também vários defeitos na reposta celular ao dano ao DNA incluindo sensibilidade a várias drogas mutagênicas, defeito no ponto de checagem de replicação do DNA e na viabilidade dos ascosporos. Além disso, o gene sldIRAD50 interage geneticamente com bimEAPC1 para o controle do spindle pole checkpoint durante a segregação cromossômica sugerindo um novo papel para o complexo Mre11. Em atuação paralela com o complexo Mre11, duas proteínas quinases ditas apicais, ATM e ATR coordenam a transdução do sinal do dano ao DNA para proteínas efetoras do reparo. A proteína ATM está mutada na síndrome de instabilidade cromossômica herdada Ataxia Telangiectasia. Para a caracterização do homologo de ATM em A. nidulans AtmA, uma linhagem mutante atmAATM foi isolada. Esse mutante apresentou falha na reposta ao dano ao DNA, como seus homólogos em vários outros organismos mostrando defeitos no ponto de checagem intrafase S e G2/M, além de sensibilidade a camptothecin e bleomicina. Ainda, o extrato protéico bruto desse mutante não foi capaz de fosforilar o homologo de NBS1 em A. nidulans, ScaA. Além das conhecidas funções de ATM na resposta ao dano ao DNA, foi verificado que o mutante atmAATM apresentou uma acelerada cinética de divisão nuclear e severos defeitos no estabelecimento e manutenção do eixo de crescimento polarizado, evidenciando uma função ainda não descrita para ATM no crescimento polar. Provavelmente, AtmA regula a função e/ou localização de proteínas chaves para a formação do eixo de polarização. Diante disso, para investigar as vias metabólicas que são controladas por esse gene, o perfil transcricional do mutante atmAATM, em comparação com a linhagem selvagem foi verificado em diferentes condições de crescimento. Os resultados indicaram um importante papel da via das pentoses fosfato na proliferação celular monitorada pela AtmA. Além disso, foram identificados vários genes com a expressão do mRNA diminuída envolvidos no crescimento polarizado, na síntese de ácido fosfatídico e de ergosterol e no tráfico intracelular, secreção e transporte vesicular. Buscando identificar genes que participam da resposta celular ao dano ao DNA causado pela droga anti topoisomerase I, camptothecin, foram utilizados filtros de macroarray de A. nidulans contendo 2787 genes deste organismo para monitorar a expressão gênica da linhagem selvagem e do mutante uvsBATR, num experimento de indução com CPT por 30, 60 e 120 minutos. Os resultados revelaram um total de 1512 e 1700 genes modulados na linhagem selvagem e uvsBATR respectivamente, em pelo menos um ponto experimental. Seis desses genes que apresentaram aumento da expressão de mRNA na linhagem selvagem e diminuição da linhagem uvsBATR foram caracterizados: fhdA (que codifica para uma proteína com domínio fork-head associated), tprA (uma proteína hipotética que apresenta o domínio tetratrico peptide repeat), mshA (um homólogo MutS6 envolvido em mismatch repair), phbA (um homólogo da prohibitina), uvsCRAD51 e cshA (homólogo da proteína CSB envolvida no reparo por excisão de nucleotídeos e ligada a Síndrome de Cockayne). A indução transcricional desses genes na presença de CPT requer a função de uvsBATR. Estes genes foram deletados e surpreendentemente apenas uvsCRAD51 apresentou sensibilidade a CPT, enquanto os outros mostraram sensibilidade a outros agentes que causam dano ao DNA e estresse oxidativo. Além disso, com exceção de uvsCRAD51, a deleção desses genes leva a supressão parcial da sensibilidade a menadiona e paraquat do mutante uvsBATR. Esses resultados indicaram um comportamento heterogêneo de sensibilidade durante o crescimento na presença de agentes que causam dano direto ou indireto ao DNA, evidenciando que o perfil transcricional não é determinante para predizer a função de um gene na proteção da célula a determinada droga que causa dano ao DNA. / The Mre11 protein complex (Mre11/Rad50/Nbs1) has emerged as a central component in the human cellular DNA damage response, and recent observations suggest that these proteins are at least partially responsible for the linking of DNA damage detection to DNA repair and cell cycle checkpoint functions. In Aspergillus nidulans, the sldI1444D mutant was isolated in a screen for dynein synthetic lethals. The sldIRAD50 gene was cloned by complementation of the sporulation deficiency phenotype of this mutant. A transversion G-C at the position 2509 (Ala-692-Proamino acid change) in the sldI1444D mutant causes sensitivity to several DNAdamaging agents. The mutation sldI1 occurs at the CXXC hinge domain of Rad50. An inactivation strain sldIRAD50::pyrG was constructed. Besides sensitivity to a number of DNA-damaging agents, this deletion strain was also impaired in the DNA replication checkpoint response and in ascospore viability. Also, sldIRAD50::pyrG geneticaly interacted with bimEAPC1, acting in the spindle pole checkpoint control during segregation, suggesting a new possible role of Mre11 complex. In parallel to the Mre11 complex, two apical quinases ATM and ATR respond to DNA damage and transduce the signal to effector proteins. In humans, mutations in ATM cause the devastating neurodegenerative disease Ataxia Telangiectasia. Here we characterized the homolog of ATM (AtmA) in the filamentous fungus A. nidulans. The deletion strain atmA presented defects in the DNA damage response as previously shown in other model organisms including intra S-phase and G2/M checkpoint defects, sensitivity to camptothecin and bleomycin. Also, the crude extract from the mutant strain did not phosphorylate the NBS1 homologue ScaA. In addition to its expected role in the DNA damage response, the atmA mutant showed increased nuclear division kinetics and severe defects in polarized hyphal growth, indicating a novel feature for the ATM gene. Probably, AtmA regulates the function and/or localization of landmark proteins required for the formation of a polarity axis. We extended these studies by investigating which pathways are controlled by AtmA during proliferation and polar growth by comparatively determining the transcriptional profile of A. nidulans wild type and atmA mutant strains in different growth conditions. Our results indicated an important role of the pentose phosphate pathway in the fungal proliferation during endogenous DNA damage and polar growth monitored by the AtmA kinase. Furthermore, we identified several genes that have decreased mRNA expression in the atmA mutant that are involved in the formation of polarized hyphae and control of polar growth; in the biosynthesis of phosphatidic acid and ergosterol; and intracellular trafficking, secretion, and vesicular transport. In order to identify genes that responded to the DNA damage mediated by the anti- toposomerase I drug, camptothecin, we used an A. nidulans macroarray carrying sequences of 2,787 genes from this fungus to monitor gene expression of both wild-type and uvsBATR in a time-point experiment where mycelium was exposed to 60, 90 and 120 minutes to the drug. The results revealed a total of 1,512 and 1,700 genes in the wild-type and uvsBATR deletion mutant strain that displayed statistically significant difference in at least one experimental time-point. We characterized six genes that have increased mRNA expression in the presence of CPT in the wild-type strain relative to the uvsBATR mutant strain: fhdA (encoding a fork head associated domain protein), tprA (encoding a hypothetical protein that contains a tetratrico peptide repeat), mshA (encoding a MutS homologue involved in mismatch repair), phbA (encoding a prohibitin homologue), uvsCRAD51 (the homologue of the RAD51 gene), and cshA (encoding a homologue of the excision repair protein ERCC-6 [Cockaynes syndrome protein]). The induced transcript levels of these genes in the presence of CPT required uvsBATR. These genes were deleted, and surprisingly, only the uvsCRAD51 mutant strain was sensitive to CPT; however, the others displayed sensitivity to a range of DNA-damaging and oxidative stress agents. Moreover, with the exception of UvsC, deletion of each of these genes partially suppressed the sensitivity of the uvsB strain to menadione and paraquat. These results indicated a very complex and heterogeneous sensitivity behavior during growth in the presence of agents that directly or indirectly cause DNA damage and the transcriptional response to DNAdamaging agents does not necessarily identify the genes that protect against these agents.

No description available.

Die in dieser Arbeit präsentierten Genomanalysen erweitern das Wissen um das genomische Potential der Roseobacter-Gruppe und zeigen mögliche Adaptionen an ökologische Nischen innerhalb mariner Lebensräume auf. In den polaren Meereisorganismen Octadecabacter arcticus 238 und O. antarcticus 307 konnten neue Eigenschaften identifiziert werden, welche bislang nicht in Vertretern der Roseobacter-Gruppe beschrieben wurden und wahrscheinlich Anpassungen an polare bzw. Meereis-assoziierte Lebensräume darstellen. Ein besonderes Highlight dieser Analysen ist die Charakterisierung einer neuen Untergruppe von Xanthorhodopsinen in den Octadecabacter-Vertretern. Diese neue Xantho¬rhodopsin-Unter¬gruppe unterscheidet sich von den bisher beschriebenen Xantho¬rhodopsinen nicht nur durch phylogenetische Verwandtschaftsbeziehungen, sondern auch in ihrer mangelnden Befähigung zur Keto-Carotenoid-Bindung und ihrer vorwiegenden Verbreitung in Organismen Eis-assoziierter Habitate. Für beide polare Octadecabacter-Vertreter wurde eine ungewöhnlich hohe Genom-plastizität festgestellt. Hierbei scheint es sich um eine Anpassung an das einzigartige Meereis¬habitat dieser Organismen zu handeln, welches als hot spot für horizontalen Gentransfer (HGT) gilt. Zudem bietet diese Genomplastizität eine Erklärung für die zahlreichen genomischen Unterschiede zwischen den Octadecabacter-Stämmen, welche in direktem Widerspruch zu der nahen Verwandtschaft dieser Organismen auf 16S rRNA-Gen¬sequenz¬ebene stehen. Trotz dieser Unterschiede weist die genetische Ausstattung von O. arcticus und O. antarcticus auffällige Übereinstimmungen auf, welche auf einen gemeinsamen exklusiven Genpool von Octadecabacter-Vertretern beider Polargebiete hindeuten. Dies wird durch 16S rRNA-basierte phylogenetische Analysen von Octadecabacter-Vertretern verschiedener Habitate unterstützt. Somit scheint zwischen Bakteriengemeinschaften beider Polarregionen eine direkte Verbindung zu existieren. Von den Polargebieten ausgehende Tiefenströmungen, welche sich über beide Hemisphären erstrecken, könnten diese Verbindung darstellen. Anhand der bislang verfügbaren Genomsequenzen wurden Verwandtschaftsbeziehungen sowie allgemeine Unterschiede zwischen Vertretern der Roseobacter-Gruppe auf vielfältigen Ebenen untersucht. Die Ergebnisse dieser Analysen geben wertvolle Einblicke in unterschiedliche Nischenadaptionen zwischen nah verwandten Roseobacter-Vertretern und in die Bedeutung von horizontalem Gentransfer für diese Gruppe. Zudem bieten sie eine Grundlage für die vereinfachte Einteilung und Analyse zukünftiger Roseobacter-assoziierter Genom– und Metagenomsequenzen.

abstract: Group III-nitride semiconductors have wide application in optoelectronic devices. Spontaneous and piezoelectric polarization effects have been found to be critical for electric and optical properties of group III-nitrides. In this dissertation, firstly, the crystal orientation dependence of the polarization is calculated and in-plane polarization is revealed. The in-plane polarization is sensitive to the lateral characteristic dimension determined by the microstructure. Specific semi-polar plane growth is suggested for reducing quantum-confined Stark effect. The macroscopic electrostatic field from the polarization discontinuity in the heterostructures is discussed, b ased on that, the band diagram of InGaN/GaN quantum well/barrier and AlGaN/GaN heterojunction is obtained from the self-consistent solution of Schrodinger and Poisson equations. New device design such as triangular quantum well with the quenched polarization field is proposed. Electron holography in the transmission electron microscopy is used to examine the electrostatic potential under polarization effects. The measured potential energy profiles of heterostructure are compared with the band simulation, and evidences of two-dimensional hole gas (2DHG) in a wurtzite AlGaN/ AlN/ GaN superlattice, as well as quasi two-dimensional electron gas (2DEG) in a zinc-blende AlGaN/GaN are found. The large polarization discontinuity of AlN/GaN is the main source of the 2DHG of wurtzite nitrides, while the impurity introduced during the growth of AlGaN layer provides the donor states that to a great extent balance the free electrons in zinc-blende nitrides. It is also found that the quasi-2DEG concentration in zinc-blende AlGaN/GaN is about one order of magnitude lower than the wurtzite AlGaN/GaN, due to the absence of polarization. Finally, the InAlN/GaN lattice-matched epitaxy, which ideally has a zero piezoelectric polarization and strong spontaneous polarization, is experimentally studied. The breakdown in compositional homogeneity is triggered by threading dislocations with a screw component propagating from the GaN underlayer, which tend to open up into V-grooves at a certain thickness of the InxAl1-xN layer. The V-grooves coalesce at 200 nm and are filled with material that exhibits a significant drop in indium content and a broad luminescence peak. The structural breakdown is due to heterogeneous nucleation and growth at the facets of the V-grooves. / Dissertation/Thesis / Ph.D. Physics 2012

Describe the topology of the polar for an irreducible curve germ of gender one and generic, we show that are non degenerate Newton. / Describiremos la topología de la polar de un germen de curva irreducible, genérica y de género uno. Para lo cual mostraremos que polar de una curva genérica en K(n;m) es Newton no degenerada.

O complexo Mre11 (Mre11/Rad50/Nbs1) é uma componente chave da resposta celular ao dano ao DNA em humanos e recentes observações sugerem que estas proteínas são em parte responsáveis pela interface ente o ensoreamento do dano ao DNA, seu reparo e as funções das proteínas envolvidas nos pontos de checagem do ciclo celular. Em Aspergillus nidulans, a partir de um screening para o isolamento de letais sintéticos na ausência de dineína, o gene sldIRAD50 foi clonado como um desses letais sintéticos através da complementação do fenótipo de deficiência de conidiação do mutante. Foi identificada uma transversão G-C na posição 2509 (Ala-692-Pro) no mutante sldI1444 a qual está presente na região de dobradiça da proteína. Essa mutação causa sensibilidade a vários agentes mutagênicos. Uma linhagem mutante sldIRAD50::pyrG foi construída a qual apresentou também vários defeitos na reposta celular ao dano ao DNA incluindo sensibilidade a várias drogas mutagênicas, defeito no ponto de checagem de replicação do DNA e na viabilidade dos ascosporos. Além disso, o gene sldIRAD50 interage geneticamente com bimEAPC1 para o controle do spindle pole checkpoint durante a segregação cromossômica sugerindo um novo papel para o complexo Mre11. Em atuação paralela com o complexo Mre11, duas proteínas quinases ditas apicais, ATM e ATR coordenam a transdução do sinal do dano ao DNA para proteínas efetoras do reparo. A proteína ATM está mutada na síndrome de instabilidade cromossômica herdada Ataxia Telangiectasia. Para a caracterização do homologo de ATM em A. nidulans AtmA, uma linhagem mutante atmAATM foi isolada. Esse mutante apresentou falha na reposta ao dano ao DNA, como seus homólogos em vários outros organismos mostrando defeitos no ponto de checagem intrafase S e G2/M, além de sensibilidade a camptothecin e bleomicina. Ainda, o extrato protéico bruto desse mutante não foi capaz de fosforilar o homologo de NBS1 em A. nidulans, ScaA. Além das conhecidas funções de ATM na resposta ao dano ao DNA, foi verificado que o mutante atmAATM apresentou uma acelerada cinética de divisão nuclear e severos defeitos no estabelecimento e manutenção do eixo de crescimento polarizado, evidenciando uma função ainda não descrita para ATM no crescimento polar. Provavelmente, AtmA regula a função e/ou localização de proteínas chaves para a formação do eixo de polarização. Diante disso, para investigar as vias metabólicas que são controladas por esse gene, o perfil transcricional do mutante atmAATM, em comparação com a linhagem selvagem foi verificado em diferentes condições de crescimento. Os resultados indicaram um importante papel da via das pentoses fosfato na proliferação celular monitorada pela AtmA. Além disso, foram identificados vários genes com a expressão do mRNA diminuída envolvidos no crescimento polarizado, na síntese de ácido fosfatídico e de ergosterol e no tráfico intracelular, secreção e transporte vesicular. Buscando identificar genes que participam da resposta celular ao dano ao DNA causado pela droga anti topoisomerase I, camptothecin, foram utilizados filtros de macroarray de A. nidulans contendo 2787 genes deste organismo para monitorar a expressão gênica da linhagem selvagem e do mutante uvsBATR, num experimento de indução com CPT por 30, 60 e 120 minutos. Os resultados revelaram um total de 1512 e 1700 genes modulados na linhagem selvagem e uvsBATR respectivamente, em pelo menos um ponto experimental. Seis desses genes que apresentaram aumento da expressão de mRNA na linhagem selvagem e diminuição da linhagem uvsBATR foram caracterizados: fhdA (que codifica para uma proteína com domínio fork-head associated), tprA (uma proteína hipotética que apresenta o domínio tetratrico peptide repeat), mshA (um homólogo MutS6 envolvido em mismatch repair), phbA (um homólogo da prohibitina), uvsCRAD51 e cshA (homólogo da proteína CSB envolvida no reparo por excisão de nucleotídeos e ligada a Síndrome de Cockayne). A indução transcricional desses genes na presença de CPT requer a função de uvsBATR. Estes genes foram deletados e surpreendentemente apenas uvsCRAD51 apresentou sensibilidade a CPT, enquanto os outros mostraram sensibilidade a outros agentes que causam dano ao DNA e estresse oxidativo. Além disso, com exceção de uvsCRAD51, a deleção desses genes leva a supressão parcial da sensibilidade a menadiona e paraquat do mutante uvsBATR. Esses resultados indicaram um comportamento heterogêneo de sensibilidade durante o crescimento na presença de agentes que causam dano direto ou indireto ao DNA, evidenciando que o perfil transcricional não é determinante para predizer a função de um gene na proteção da célula a determinada droga que causa dano ao DNA. / The Mre11 protein complex (Mre11/Rad50/Nbs1) has emerged as a central component in the human cellular DNA damage response, and recent observations suggest that these proteins are at least partially responsible for the linking of DNA damage detection to DNA repair and cell cycle checkpoint functions. In Aspergillus nidulans, the sldI1444D mutant was isolated in a screen for dynein synthetic lethals. The sldIRAD50 gene was cloned by complementation of the sporulation deficiency phenotype of this mutant. A transversion G-C at the position 2509 (Ala-692-Proamino acid change) in the sldI1444D mutant causes sensitivity to several DNAdamaging agents. The mutation sldI1 occurs at the CXXC hinge domain of Rad50. An inactivation strain sldIRAD50::pyrG was constructed. Besides sensitivity to a number of DNA-damaging agents, this deletion strain was also impaired in the DNA replication checkpoint response and in ascospore viability. Also, sldIRAD50::pyrG geneticaly interacted with bimEAPC1, acting in the spindle pole checkpoint control during segregation, suggesting a new possible role of Mre11 complex. In parallel to the Mre11 complex, two apical quinases ATM and ATR respond to DNA damage and transduce the signal to effector proteins. In humans, mutations in ATM cause the devastating neurodegenerative disease Ataxia Telangiectasia. Here we characterized the homolog of ATM (AtmA) in the filamentous fungus A. nidulans. The deletion strain atmA presented defects in the DNA damage response as previously shown in other model organisms including intra S-phase and G2/M checkpoint defects, sensitivity to camptothecin and bleomycin. Also, the crude extract from the mutant strain did not phosphorylate the NBS1 homologue ScaA. In addition to its expected role in the DNA damage response, the atmA mutant showed increased nuclear division kinetics and severe defects in polarized hyphal growth, indicating a novel feature for the ATM gene. Probably, AtmA regulates the function and/or localization of landmark proteins required for the formation of a polarity axis. We extended these studies by investigating which pathways are controlled by AtmA during proliferation and polar growth by comparatively determining the transcriptional profile of A. nidulans wild type and atmA mutant strains in different growth conditions. Our results indicated an important role of the pentose phosphate pathway in the fungal proliferation during endogenous DNA damage and polar growth monitored by the AtmA kinase. Furthermore, we identified several genes that have decreased mRNA expression in the atmA mutant that are involved in the formation of polarized hyphae and control of polar growth; in the biosynthesis of phosphatidic acid and ergosterol; and intracellular trafficking, secretion, and vesicular transport. In order to identify genes that responded to the DNA damage mediated by the anti- toposomerase I drug, camptothecin, we used an A. nidulans macroarray carrying sequences of 2,787 genes from this fungus to monitor gene expression of both wild-type and uvsBATR in a time-point experiment where mycelium was exposed to 60, 90 and 120 minutes to the drug. The results revealed a total of 1,512 and 1,700 genes in the wild-type and uvsBATR deletion mutant strain that displayed statistically significant difference in at least one experimental time-point. We characterized six genes that have increased mRNA expression in the presence of CPT in the wild-type strain relative to the uvsBATR mutant strain: fhdA (encoding a fork head associated domain protein), tprA (encoding a hypothetical protein that contains a tetratrico peptide repeat), mshA (encoding a MutS homologue involved in mismatch repair), phbA (encoding a prohibitin homologue), uvsCRAD51 (the homologue of the RAD51 gene), and cshA (encoding a homologue of the excision repair protein ERCC-6 [Cockaynes syndrome protein]). The induced transcript levels of these genes in the presence of CPT required uvsBATR. These genes were deleted, and surprisingly, only the uvsCRAD51 mutant strain was sensitive to CPT; however, the others displayed sensitivity to a range of DNA-damaging and oxidative stress agents. Moreover, with the exception of UvsC, deletion of each of these genes partially suppressed the sensitivity of the uvsB strain to menadione and paraquat. These results indicated a very complex and heterogeneous sensitivity behavior during growth in the presence of agents that directly or indirectly cause DNA damage and the transcriptional response to DNAdamaging agents does not necessarily identify the genes that protect against these agents.

Detta arbete undersöker förhållandet mellan kvalitetsparametrar i frityrolja, såsom halten fria fettsyror (FFA), anisidinvärdet (AV) och %TPM (Total Polar Materials) samt Agtronvärdet hos köttbullar efter fritering. Kvalitetsparametrar hos frityrolja, såsom primära och sekundära oxidationsprodukter, kan mätas för att utvärdera oljans kvalitet då nivåerna ofta ökar i samband med oljans användning. Primära oxidationsprodukter, såsom peroxider, kan mätas med hjälp av ett så kallat peroxidvärde (PV) och sekundära oxidationsprodukter, såsom aldehyder, kan mätas med hjälp av anisidinvärdet. Analys av %TPM och FFA är exempel på andra metoder för att mäta kvaliteten hos en olja då polariteten ökar i takt med oljans användning. Halten FFA i oljan undersöktes med hjälp av titrering med natriumhydroxid och %TPM mättes med hjälp av mätinstrumentet Testo 270. Agtronvärdet hos köttbullarna mättes med hjälp av instrumentet Agtron E30FP, som använder IR-teknologi för att bestämma färgen på en produkt. Resultaten visade att halten FFA, AV och %TPM i frityroljan ökade med tiden under samtliga fyra produktionsdagar. Hypotesen att produkten bör vara mörkare, det vill säga att Agtronvärdet bör vara lägre vid produktionens slut jämfört med början stödjs av resultaten från två av fyra produktionsdagar. Slutsatsen drogs att det fanns skillnader i oljans sammansättning, med hänsyn till FFA, AV och %TPM vid produktionsdagens slut jämfört med start. Däremot kunde ingen tydlig koppling ses mellan dessa förändringar och en minskning av Agtronvärdet hos köttbullarna över tiden. Ytterligare studier behövs således för att kunna dra en slutsats kring sambandet mellan kvalitetsparametrar i frityrolja och färgen på det friterade livsmedlet. / This study examines the relationship between quality parameters of frying oil, such as Free fatty acids (FFA), the Anisidine Value (AV) and Total Polar Materials (%TPM), as well as the Agtron Value of meatballs after deep frying. Quality parameters in frying oil, such as primary and secondary oxidation products, measure the quality of the frying oil since levels increase with the use of the oil. Primary oxidation products, such as peroxides, can be measured by the Peroxide Value (PV) and secondary oxidation products, such as aldehydes, can be measured by the Anisidine Value. Analysis of %TPM and FFA are other methods to measure the quality of an oil, since the polarity increases as the oil is used for frying. The instrument Testo 270 was used to measure %TPM in the oil and FFA was determined by titration with sodium hydroxide. The Agtron E30FP instrument was used to determine the Agtron Values of the meatballs, wich used IR technology to determine the color of the product. Results showed that the FFA, AV and %TPM of the oil increased over time in all four production days. It was expected that the product should be darker, that is, the Agtron Value should be lower at the end of production compared to the beginning, but this was only seen in two out of four production days. It was concluded that there are differences in the composition of the oil, with regard to FFA, AV and %TPM at the end of the production day compared to the beginning of the day, but no clear connection was seen between these changes and a decrease in the Agtron Value of the meatballs over time. Further studies are needed to be able to draw a conclusion about the relationship between quality parameters of frying oil and the color of the fried food.

No description available.

Master of Science / Department of Grain Science and Industry / Jon M. Faubion / Endosperm texture is an important characteristic in determining wheat processing and end-use. The presence of puroindoline proteins on the starch surface is the biochemical marker for wheat hardness. Near-isogenic samples over expressing puroindolines have been used to assess the effect of wheat hardness on final product characteristics. The objective of this study was to determine differences among starch isolated from near-isogenic samples and to investigate the role starch surface components play in pasting. The use of near-isogenic samples over expressing puroindolines combined with the use of two methods of starch isolation (batter and dough) was an effective means to create samples with varied amounts of surface components. Starch thermal properties were characterized and surface proteins and lipids were quantified. Starch isolated from hard wheat cultivars presented more similarities with starch isolated from its soft near-isogenic line when a dough method was used than when a batter method was used. Starch from soft experimental lines isolated using a batter method showed increased MVA peak viscosity, breakdown and swelling power. Increased levels of LysoPC in starch isolated from hard wheat cultivars or soft experimental lines by dough method could have complexed with amylose and restricted granule swelling. Thereby, decreasing peak viscosity, breakdown and swelling power.

Doctor of Philosophy / Department of Grain Science and Industry / Jon M. Faubion / Starch granule surface components were studied as a function of puroindoline haplotype, starch isolation method, and processing fraction. Commonly grown cultivars and near-isogenic wheat lines that varied in their wheat endosperm hardness were collected. Wheat whole-meal, flour and starch were evaluated for their polar lipid composition. Water-washed starch was isolated using a modified batter method and a dough method. Direct infusion tandem mass spectrometry was used to identify the lipid species in the extracts. A total of 155 polar lipid species in wheat meal, flour and starch were quantitatively characterized. The predominant polar lipid classes were digalactosyldiglycerides, monogalactosyldiglycerides, phosphatidylcholine, and lysophosphatidylcholine. Wheat whole-meal, flour and surface-starch contained greater concentrations of total galactolipids while internal-starch lipids contained greater concentrations of monoacyl phospholipids. Wide ranges in starch surface polar lipid concentrations were observed between the two starch isolation methods. Starch isolation methods provided a greater source of variation than did wheat kernel hardness. When dough is optimally mixed the lipids originally on the surface of wheat starch become incorporated into the gluten phase of the dough, whereas in a batter system the starch-surface lipids stay associated with the starch granule surface. The greatest quantities of polar lipids on the starch surface occurred when both puroindoline proteins were present on starch in their wild-type form. Starch surface polar lipid content decreased dramatically when one of the puroindoline proteins was null, or if the puroindoline-b (pin-b) was in the mutated form (Tryptophan-44 to Arginine). Within the hard textured samples, more polar lipids were present on the starch surface when pin-b was in its wild-type form and puroindoline-a (pin-a) was null than when pin-a was in its wild-type form and pin-b was null. The lowest amount of polar lipids were present when pin-b was mutated (Tryptophan-44 to Arginine) and pin-a was in its wild-type form. This indicates the relative importance of pin-b’s presence and structure as it relates to lipid association with the starch granule surface.