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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

Cloning and characterisation of the HMA3 gene and its promoter from Arabidopsis halleri (L.) O'Kane and Al'Shehbaz and Arabidopsis thaliana (L.) Heynhold

Hoffmann, Toni January 2007 (has links)
Being living systems unable to adjust their location to changing environmental conditions, plants display homeostatic networks that have evolved to maintain transition metal levels in a very narrow concentration range in order to avoid either deficiency or toxicity. Hence, plants possess a broad repertoire of mechanisms for the cellular uptake, compartmentation and efflux, as well as for the chelation of transition metal ions. A small number of plants are hypertolerant to one or a few specific transition metals. Some metal tolerant plants are also able to hyperaccumulate metal ions. The Brassicaceae family member Arabidopis halleri ssp. halleri (L.) O´KANE and AL´SHEHBAZ is a hyperaccumulator of zinc (Zn), and it is closely related to the non-hypertolerant and non-hyperaccumulating model plant Arabidopsis thaliana (L.) HEYNHOLD. The close relationship renders A. halleri a promising emerging model plant for the comparative investigation of the molecular mechanisms behind hypertolerance and hyperaccumulation. Among several potential candidate genes that are probably involved in mediating the zinc-hypertolerant and zinc-hyperaccumulating trait is AhHMA3. The AhHMA3 gene is highly similar to AtHMA3 (AGI number: At4g30120) in A. thaliana, and its encoded protein belongs to the P-type IB ATPase family of integral membrane transporter proteins that transport transition metals. In contrast to the low AtHMA3 transcript levels in A. thaliana, the gene was found to be constitutively highly expressed across different Zn treatments in A. halleri, especially in shoots. In this study, the cloning and characterisation of the HMA3 gene and its promoter from Arabidopsis halleri (L.) O´KANE and AL´SHEHBAZ and Arabidopsis thaliana (L.) HEYNHOLD is described. Heterologously expressed AhHMA3 mediated enhanced tolerance to Zn and to a much lesser degree to cadmium (Cd) but not to cobalt (Co) in metal-sensitive mutant strains of budding yeast. It is demonstrated that the genome of A. halleri contains at least four copies of AhHMA3, AhHMA3-1 to AhHMA3-4. A copy-specific real-time RT-PCR indicated that an AhHMA3-1 related gene copy is the source of the constitutively high transcript level in A. halleri and not a gene copy similar to AhHMA3-2 or AhHMA3-4. In accordance with the enhanced AtHMA3mRNA transcript level in A. thaliana roots, an AtHMA3 promoter-GUS gene construct mediated GUS activity predominantly in the vascular tissues of roots and not in shoots. However, the observed AhHMA3-1 and AhHMA3-2 promoter-mediated GUS activity in A. thaliana or A. halleri plants did not reflect the constitutively high expression of AhHMA3 in shoots of A. halleri. It is suggested that other factors e. g. characteristic sequence inserts within the first intron of AhHMA3-1 might enable a constitutively high expression. Moreover, the unknown promoter of the AhHMA3-3 gene copy could be the source of the constitutively high AhHMA3 transcript levels in A. halleri. In that case, the AhHMA3-3 sequence is predicted to be highly homologous to AhHMA3-1. The lack of solid localisation data for the AhHMA3 protein prevents a clear functional assignment. The provided data suggest several possible functions of the AhHMA3 protein: Like AtHMA2 and AtHMA4 it might be localised to the plasma membrane and could contribute to the efficient translocation of Zn from root to shoot and/or to the cell-to-cell distribution of Zn in the shoot. If localised to the vacuolar membrane, then a role in maintaining a low cytoplasmic zinc concentration by vacuolar zinc sequestration is possible. In addition, AhHMA3 might be involved in the delivery of zinc ions to trichomes and mesophyll leaf cells that are major zinc storage sites in A. halleri. / Pflanzen sind lebende Systeme, die nicht in der Lage sind ihren Standort sich ändernden Umweltbedingungen anzupassen. Infolgedessen weisen Pflanzen homöostatischeNetzwerke auf, welche die Mengen an intrazellulären Übergangsmetallen in einem sehr engen Konzentrationsbereich kontrollieren um somit Vergiftungs- oder Mangelerscheinungen zu vermeiden. Eine kleine Anzahl von Pflanzen ist hypertolerant gegenüber einem oder mehreren Übergangsmetallen. Einige wenige dieser metalltoleranten Pflanzen sind fähig Übergangsmetalle in beträchtlichen Mengen zu speichern, sprich zu hyperakkumulieren, ohne Vergiftungserscheinungen zu zeigen. Die Haller’sche Schaumkresse (Arabidopis halleri ssp. halleri (L.) O´KANE und AL´SHEHBAZ) aus der Familie der Kreuzblütler (Brassicaceae) ist ein solcher Hyperakkumulator für Zink (Zn). Sie ist nah verwandt mit der Modellpflanze Ackerschmalwand (Arabidopsis thaliana (L.) HEYNHOLD), die jedoch nicht-hypertolerant und nicht-hyperakkumulierend für Übergangsmetalle ist. Diese nahe Verwandtschaft erlaubt vergleichende Studien der molekularen Mechanismen, die Hypertoleranz und Hyperakkumulation zu Grunde liegen. Zu der Gruppe von Kandidatengenen, die möglicherweise von Bedeutung für die Zink-hypertoleranten und -hyperakkumulierenden Eigenschaften von A. halleri sind, gehört AhHMA3, ein Gen mit großer Ähnlichkeit zu AtHMA3 (AGI Nummer: At4g30120) aus A. thaliana. Es kodiert ein Protein aus der Familie transmembraner Übergangsmetall-Transportproteine, den P-typ IB ATPasen. Im Gegensatz zu den niedrigen AtHMA3 Transkriptmengen in A. thaliana wird das AhHMA3 Gen in A. halleri in Gegenwart verschiedener Zn Konzentrationen konstitutiv hoch exprimiert, insbesondere im Spross der Pflanze. Diese Arbeit beschreibt die Klonierung und Charakterisierung des HMA3 Gens und seines Promoters aus A. halleri und A. thaliana. Es wurde gezeigt, dass heterolog exprimiertes AhHMA3 Protein in metallsensitiven Hefestämmen eine erhöhte Toleranz gegenüber Zink und zu einem geringen Grad gegenüber Kadmium (Cd) jedoch nicht gegenüber Kobalt (Co) vermittelt.Weiterhin wurden im Genom von A. halleri mindestens vier AhHMA3 Genkopien, AhHMA3-1 bis AhHMA3-4, nachgewiesen. Eine Genkopie-spezifische Echtzeit-RT-PCR (real-time RT-PCR) deutete darauf hin, dass eine zu AhHMA3-1 und nicht zu AhHMA3-2 oder AhHMA3-4 ähnliche Genkopie die Quelle der konstitutiv hohen Transkriptmengen in A. halleri ist. In Übereinstimmung mit erhöhten mRNS Transkriptmengen inWurzeln von A. thaliana, vermittelte ein AtHMA3 Promoter-GUS (ß-Glucuronidase) Genkonstrukt GUS-Aktivität hauptsächlich in den Leitgeweben der Wurzeln jedoch nicht des Sprosses. Die vermittelte GUS-Aktivität durch Promoterfragmente von AhHMA3-1 und AhHMA3-2 in A. thaliana oder A. halleri Pflanzen spiegelte jedoch nicht die konstitutiv hohe AhHMA3 Expression im Spross von A. halleri wieder. Es wird vermutet, dass andere Faktoren die konstitutiv hohe Expression ermöglichen wie zum Beispiel die gefundenen kopiespezifischen Sequenzinsertionen innerhalb des ersten AhHMA3-1 Introns. Weiterhin ist es denkbar, dass der unbekannte Promoter der AhHMA3-3 Genkopie die Quelle der konstitutiv hohen AhHMA3 Transkriptmengen ist. In diesem Fall wird eine sehr hohe Ähnlichkeit zwischen den Sequenzen von AhHMA3-3 und der AhHMA3-1 vorhergesagt. Es konnten keine deutlichen Ergebnisse zur intrazellulären Lokalisierung gemacht werden, die eine exakte Einordnung der Funktion des AhHMA3 Proteins erlauben würden. Die bisher ermittelten Ergebnisse schlagen jedoch mehrere mögliche Funktionen für AhHMA3 vor: Ähnlich den AhHMA3 homologen Proteinen, AtHMA2 und AtHMA4, könnte AhHMA3 in der Plasmamembran der Zelle sitzen und dort zur effizienten Translokation von Zink aus der Wurzel in den Spross und/oder zur Zell-zu-Zell Verteilung von Zn im Spross beitragen. Falls AhHMA3 in der Membran der Vakuole sitzt, könnte es eine Rolle bei der Aufrechterhaltung niedriger zytoplasmatischer Zinkkonzentrationen durch vakuoläre Zinksequestrierung spielen. Zusätzlich ist es denkbar, dass AhHMA3 an der Abgabe von Zinkionen an Trichome und Blattmesophyllzellen beteiligt ist, die die Haupteinlagerungsorte für Zink in A. halleri darstellen.
162

Räumliche und zeitliche Aspekte der intrazellulären pH-Regulation in Epithelien / Spatial and temporal characteristics of intracellular pH-regulation in epithelial cells

Schewe, Bettina January 2008 (has links)
Die Speicheldrüsen der Schmeißfliege Calliphora vicina produzieren bei Stimulierung mit dem Neurohormon Serotonin (5-Hydroxytryptamine, 5-HT) einen KCl-reichen Primärspeichel. Der transepitheliale K+-Transport wird durch eine apikal lokalisierte vakuoläre H+-ATPase (V-ATPase) energetisiert. Stimulierung der Speicheldrüsen mit 5-HT aktiviert die apikale V-ATPase, die Protonen aus der Zelle in das Drüsenlumen transportiert. Trotz des auswärts gerichteten Protonentransportes führt die 5-HT-Stimulierung kurioserweise zu einer intrazellulären Ansäuerung. Die Ursachen dieser 5-HT-induzierten Ansäuerung waren unzureichend untersucht. Deshalb war das Ziel dieser Arbeit die Identifikation aller Transporter, die an der intrazellulären pH-(pHi)-Regulation in unstimulierten Speicheldrüsen von Calliphora vicina beteiligt sind und an der Entstehung und Regulation der 5-HT-induzierten pHi-Änderungen mitwirken. Von besonderem Interesse war hierbei die funktionelle Mitwirkung der V-ATPase, deren Beteiligung an der pHi-Regulation in tierischen Zellen bisher wenig untersucht war. Wesentliche Ergebnisse dieser Arbeit waren: • Messungen des pHi-Wertes in der unstimulierten Drüse zeigten, dass vor allem die V-ATPase und mindestens ein Na+-abhängiger HCO3--Transporter an der Aufrechterhaltung des Ruhe-pHi beteiligt sind. • Zur Wiederherstellung des Ruhe-pHi nach einer intrazellulären Ansäuerung (NH4Cl-Vorpuls) tragen ebenfalls im Wesentlichen die V-ATPase und mindestens ein Na+-abhängiger HCO3--Transporter bei. Der Na+/H+-Antiporter hat in der unstimulierten Drüse keinen messbaren Einfluss auf den Ruhe-pHi. • Die Wiederherstellung des Ruhe-pHi nach einer intrazellulären Alkalisierung (Na-acetat-Vorpuls) ist Cl--abhängig, aber auch unter extremen Bedingungen waren die Zellen noch in der Lage sich vollständig von einer intrazellullären Alkalisierung zu erholen. Einen entscheidenden Anteil daran hat offenbar die hohe intrazelluläre Puerkapazität. • Ein Na+-abhängiger Glutamat-Transporter ist per se kein pHi-regulierender Transporter, seine Aktivität hat jedoch Einfluss auf den Ruhe-pHi in der unstimulierten Speicheldrüse von Calliphora vicina. • 10 nM 5-HT induzieren in den Calliphora Speicheldrüsen eine intrazelluläre Ansäuerung. An dieser Ansäuerung ist der Na+/H+-Antiporter entscheidend beteiligt. Auch eine klare Cl--Abhängigkeit der 5-HT-induzierten Ansäuerung konnte beobachtet werden. Wahrscheinlich ist eine gekoppelte Aktivität von Na+/H+-Antiporter und Cl-/HCO3--Antiporter. • Messungen mit einem O2-empndlichen Fluoreszenzfarbstoff zeigten, dass Stimulierung der Speicheldrüsen mit 5-HT die Zellatmung aktivierte. Der cAMP- und der IP3/Ca2+-Weg tragen auf komplexe Weise zu der 5-HT-induzierten Aktivierung der Zellatmung und damit auch zu den 5-HT-induzierten pHi-Änderungen bei. • Mit molekularbiologischen Untersuchungen ist es gelungen den Na+-abhängigen Glutamat-Transporter, den Na+/H+-Antiporter, die Carboanhydrase und die Untereinheit C der V-ATPase in den Calliphora Speicheldrüsen direkt nachzuweisen. Zudem konnte erstmals der direkte Nachweis für die Expression eines nH+/K+-Antiporters in den Speicheldrüsen von Calliphora vicina erbracht werden. Diese Arbeit trug ganz wesentlich zum Verständnis der pHi-Regulation in der unstimulierten und stimulierten Speicheldrüse von Calliphora vicina bei. Mechanismen die zur Aufrechterhaltung und Wiederherstellung des Ruhe-pHi nach einer intrazellulären Ansäuerung bzw. Alkalisierung beitragen, konnten mit pHi-Messungen und auch molekularbiologisch nachgewiesen werden. Die Mechanismen, welche die 5-HT-induzierte intrazelluläre Ansäuerung verursachen, konnten ebenfalls aufgeklärt werden. Zudem wurde an den Calliphora Speicheldrüsen eine neue optische Methode zur Messung des O2-Verbrauchs in tierischen Geweben etabliert. / The tubular salivary glands of the blowfly Calliphora vicina consist of a single layer of epithelial cells. Stimulation with the neurohormone serotonin (5-hydroxytryptamine,5-HT) induces the secretion of a KCl-rich primary saliva. Transepithelial K+-transport is energized by a vacuolar-type H+-ATPase (V-ATPase) which is located in the apical membrane. 5-HT stimulates the apical V-ATPase which transports protons out of the cells into the lumen of the glands. Despite this outward directed proton transport, 5-HT stimulation leads to an intracellular acidication. The causes of this intracellular acidication were poorly understood. Therefore the aim of this thesis was the identication of all pHi regulating transporters which are involved in pHi regulation in the unstimulated salivary glands of Calliphora vicina and which contribute to the 5-HT-induced pHi changes. Of special interest was the functional role of the V-ATPase,whose contribution to pHi regulation in animal cells is, as yet, not well studied. Key results were: • pHi measurements in unstimulated glands showed that mainly the V-ATPase and at least one Na+-dependent HCO3--transporter are involved in maintenance of resting pHi. • V-ATPase and at least one Na+-dependent HCO3--transporter are also necessary for the recovery from an intracellular acidication (NH4Cl prepulse). • Recovery from an intracellular alkali load (Na-acetate prepulse) is partially Cl--dependent. • A Na+ dependent gluatamate-transporter is present in Calliphora salivary glands and its activity aects the resting pHi. • 10 nM 5-HT induce an intracellular acidication. This acidication is Na+-dependent, EIPA-sensitive and also Cl--dependent. No DIDS-sensitivity was observed. A coupled activity of a Na+/H+-antiporter and a Cl-/HCO3- -antiporter was suggested. • Using O2-sensitive fluorescent microbeads I could show that 5-HT stimulation of the Calliphora salivary glands activates cellular respiration. The cAMP and Ca2+-signalling pathways contribute in a complex manner to the 5-HT-induced activation of cellular respiration and consequently, also to the 5-HT-induced intracellular acidication. • The expression of a Na+ dependent glutamate-transporter, a Na+/H+-antiporter, a carbonic anhydrase, subunit C of the V-ATPase and a nH+/K+-antiporter were determined on mRNA level by RT-PCR. This thesis contributes signicantly to the understanding of pHi regulation in unstimulated and stimulated salivary glands of Calliphora vicina. Mechanisms which contribute to the maintenance and recovery of resting pHi were identied by using pHi measurements and molecular biological techniques. Mechanisms which are responsible for the 5-HT-induced intracellular acidication were also clarified. Furthermore a new optical method for measuring O2 consumption in animals cells was established by using the Calliphora salivary glands as a model.
163

Neuartige Myosin ATPase-Inhibitoren auf der Basis polyhalogenierter Pyrrolalkaloide und stereoselektive Synthese hormonell aktiver Steroide

Martin, René 07 January 2009 (has links) (PDF)
Während meiner Dissertation beschäftigte ich mich mit der Synthese von polyhalogenierten Pyrrolalkaloiden. Im Zentrum der Darstellung dieser Verbindungen stand die von mir in meiner Diplomarbeit erfolgreich zur Synthese von Pentabrompseudilin angewandte silber-katalysierte Cyclisierung von N-tosylsubstituierten Homopropargylaminen. So konnte das Pentachlorpseudilin in der zweiten Totalsynthese überhaupt sowie mehrere gemischt halogenierte synthetische Derivate aufgebaut werden. Diese Verbindungen konnten in einer Kooperation mit Herrn Prof. Gutzeit aus der Fachrichtung Biologie der TU Dresden und Herrn Prof. Manstein von der Medizinischen Hochschule Hannover, als hochwirksame Myosin ATPase-Inhibitoren identifiziert werden. Bei den verschieden halogenierten Verbindungen ließen sich deutliche Unterschiede in der inhibitorischen Aktivität feststellen. Ein zum Pentabrompseudilin benzologes Indolderivat, welches in einer kurzen Synthese aufgebaut werden konnte, war hingegen nicht aktiv. Im zweiten Teil der Promotion beschäftigte ich mich in einer Kooperation mit Dr. Kurzchalia vom Max-Planck-Institut für Molekulare Zellbiologie und Genetik (Dresden) mit der Synthese von hormonell aktiven Steroiden, speziell den Cholesten-26-säuren, welche Liganden für den hormonellen Rezeptor DAF-12 des Nematoden Caenorhabditis elegans repräsentieren. Die an C-25 R-konfigurierten Säuren waren in der Literatur mit einer deutlich geringeren Aktivität als die 25S-Säuren beschrieben. Die 25R-Steroide waren synthetisch leicht aus kommerziell erhältlichem Diosgenin zugänglich. So konnten alle drei 25R-Säuren in kurzen Synthesen dargestellt werden. In deren Verlauf wurden verschiedene Oxidations- und Schutzgruppenreaktionen eindrucksvoll angewendet. Für die Einführung der 25S-Konfiguration in der Seitenkette sollte eine EVANS-Aldolreaktion an geeignetem Startmaterial angewandt werden. In der Tat führte die Verwendung eines chiralen Oxazolidinons stereoselektiv zum gewünschten Enantiomer in sehr guten Ausbeuten, selbst bei großen Ansätzen. Zur weiteren Transformation musste die durch die Aldolreaktion eingeführte Hydroxygruppe an C-24 entfernt werden. Dies gelang in exzellenter Ausbeute mit Hilfe einer radikalischen Deoxygenierung nach BARTON und MCCOMBIE. So konnte in acht Stufen ein zentrales Syntheseintermediat gewonnen werden, dass in alle drei Naturstoffe überführt werden konnte. Damit waren ausreichende Mengen für biologische Untersuchungen hergestellt worden. Mit der gesättigten (25S)-Dafachronic Acid konnte ein neuer Ligand für DAF-12 synthetisiert werden. Gleichzeitig konnte gezeigt werden, dass die Existenz einer Doppelbindung in den Cholesten-26-säuren für die biologische Aktivität unerheblich ist. Für weitere biologische Tests konnten neue Normethylderivate des Cholesterols gewonnen werden. Diese zeigten zum Teil ungewöhnliche biologische Aktivität. Außerdem wurden Versuche zu an verschiedenen Positionen bromierten Cholesterolderivaten unternommen. Im letzten Teil meiner Dissertation konnten neue hoch hydroxylierte Steroide dargestellt werden, die in einer Kooperation mit Prof. Franzblau vom Institute for Tuberculosis Research (Chicago, USA) auf ihre Aktivität gegen Mycobacterium tuberculosis getestet werden sollten. Dabei konnte eine ungewöhnliche 1,2-anti-Hydroborierung beoachtet werden, deren Mechanismus noch genauer untersucht werden muss.
164

Synthese halogenierter Carbazole und Totalsynthese der Amaryllisalkaloide Pratosin und Hippadin

Kirst, Juliane 14 July 2009 (has links) (PDF)
Während meiner Dissertation beschäftigte ich mich mit der Synthese von polyhalogenierten Carbazolderivaten. Das Carbazolgerüst wurde über den Palladiumvermittelten, bestehend aus Buchwald-Hartwig-Aminierung und oxidativer Cyclisierung, aufgebaut. Die Halogensubstituenten wurden entweder am Carbazol eingeführt oder bereits über die Startmoleküle in die Synthese eingebracht. Somit konnten verschiedene halogenierte halogenierte Derivate synthetisiert werden. Diese Verbindungen konnten in einer Kooperation mit Herrn Prof. Gutzeit aus der Fachrichtung Biologie der TU Dresden auf ihre Aktivität in der Inhibierung der Myosin ATPase untersucht werden. Dabei wurde ein tribromiertes 1-Hydroxycarbazol als wirksamer Inhibitor identifiziert. Der zweite Teil der Promotion umfasst die Darstellung der Amaryllisalkaloide Pratosin und Hippadin, sowie der auf diesem Weg ebenfalls zugänglichen Naturstoffe Assoanin, Oxoassoanin, Anhydrolycorin-7-on und deren Naturstoffanaloga Anhydrolycorin. Die Synthese wurde auf zwei verschiedenen Wegen durchgeführt und beinhaltet als Schlüsselreaktionen die Eisenvermittelte C-C und C-N Bindungsbildung, sowie die Palladiumvermittelte Biarylkupplung. / This thesis is about my research study of the synthesis of polyhalogenated carbazoles. The skeletal structure of the carbazoles are easily assembled by palladium(0)-catalyzed Buchwald-Hartwig coupling and palladium(II)-mediated oxidative cyclisation. Through cooperation with Prof. Gutzeit many different halogenated carbazole derivatives could be analyzed concerning the activity of the inhibition of myosin ATPase. The tribrominated 1-Hydroxycarbazole was identified as sn effective inhibitor. The second part of my thesis includes the total synthesis of amaryllidaceae alkaloids pratosine, oxoassoanine, assoanine, hippadine, anhydrolycorinone and anhydrolycorine. The synthesis was accomplished by two different pathways which include the Iron-mediated C-C and C-N bond formation and intramolecular palladium-catalysed biaryl coupling reaction as the key steps.
165

Caracterização de uma cálcio ATPase PMR1 de \'Aspergillus fumigatus\' / Characterization of an Aspergillus fumigatus PMR1 calcium ATPase.

Frederico Marianetti Soriani 05 September 2006 (has links)
Os conhecimentos sobre a regulação dos níveis de cálcio e manganês no Aspergillus fumigatus são bastante limitados, sendo que a homeostase destes íons pode ser diretamente controlada pela ação de ATPases específicas, dentre elas as cálcio ATPases da subfamília PMR1. Desta forma, o objetivo do presente estudo foi a expressão, caracterização e validação como alvo quimioterapêutico do gene Afpmr1 de A. fumigatus. Inicialmente, foi realizada a complementação funcional, de uma cepa de S. cerevisiae nocaute para a PMR1, em meios de cultura suplementados com EGTA ou manganês, revertendo o fenótipo da cepa nocute. Além disto, após expressão do gene Afpmr1, foi verificada uma reversão na intensa distribuição de quitina na parede celular da cepa nocaute. Paralelamente, para a RNAi, um fragmento do gene Afpmr1 apresentando baixa identidade com outros genes de cálcio ATPases de diferentes espécies foi clonado em vetor de expressão em A. fumigatus (pALB1). Após indução da expressão, a construção de RNA dupla fita para RNAi silenciou tanto o gene alb1 isoladamente (clone controle), quanto o duplo silenciamento com o gene de interesse Afpmr1, conferindo à ambas construções coloração branca às colônias. Uma vez confirmado o silenciamento gênico, por técnicas de RT-PCR quantitativo, os clones selecionados foram utilizados em ensaios de fagocitose e killing de macrófagos. O clone com o gene Afpmr1 silenciado apresentou diminuição na porcentagem de fagocitose, no número médio de conídios fagocitados e na eficiência de eliminação destes conídios quando comparados com seus controles. Estes resultados mostram que o gene Afpmr1 pode ser expresso funcionalmente em sistemas heterólogos e seu silenciamento, em A. fumigatus, influencia processos celulares que podem estar relacionados à manutenção da estrutura e composição da parede celular, além de desencadear alterações na fagocitose e killing de macrófagos. / The knowledge about the regulation of Aspergillus fumigatus calcium and manganese levels are very limited, while these ions homeostasis could be directly controlled by the function of specific ATPases, like the PMR1 calcium ATPase. In this way, the aim of the present work was the expression, characterization e validation, as chemotherapeutic target, of the A. fumigatus Afpmr1 gene. Initially, the functional complementation of a PMR1 knock-out strain phenotype was analyzed in EGTA or manganese supplemented culture media. Besides, after Afpmr1 expression, an intense distribution of chitin through the cell wall of the knock-out strain was reversed. At the same time, a fragment of the Afpmr1 gene, showing low identity values for another calcium ATPase genes, was cloned in an A. fumigatus expression vector (pALB1) for RNAi. After the induction of gene expression, a double strand RNA construct for RNAi has properly silenced either the alb1 gene alone (control clone), or the double silencing with the gene of interest Afpmr1, leading to both constructions white colored colonies. After confirmation of the gene silencing by quantitative RT-PCR techniques, the selected clones were used in macrophages killing and phagocytosis assays. The Afpmr1 silenced clone showed a decrease in the phagocytosis percentage, in the mean number of internalized conidia and in the killing percentage when compared with control groups. These results show that the Afpmr1 gene can be functionally expressed in eukaryotic heterologous systems and its silencing, in A. fumigatus, alters cellular processes that can be related with the maintenance of the cell wall structure and composition, as well as promote alterations in the macrophages phagocytosis and killing.
166

Efeitos da administração de ácido fólico sobre parâmetros comportamentais, bioquímicos e morfológicos em ratos submetidos à hipóxia-isquemia encefálica neonatal

Carletti, Jaqueline Vieira January 2012 (has links)
Estudos com animais submetidos ao modelo de hipóxia-isquemia (HI) neonatal reproduzem achados observados em humanos, tais como transtornos de aprendizado, comprometimento tecidual nervoso e alterações bioquímicas. O ácido fólico (AF), uma vitamina que pode ser obtida diretamente da dieta, tem sido relacionado à prevenção de eventos isquêmicos, e a proteção antioxidante. O objetivo deste estudo foi investigar o papel do tratamento com ácido fólico sobre parâmetros comportamentais, bioquímicos e morfológicos de animais submetidos à HI. Foram utilizados ratos Wistar de ambos os sexos com sete dias pós-natal (DPN) divididos em quatro grupos: 1) grupo controle tratado com salina 0,9% (CTS); 2) grupo controle tratado com ácido fólico (CTAF); 3) grupo HI tratado com salina 0,9% (HIS); 4) grupo HI tratado com ácido fólico (HIAF). Uma dose intraperitoneal de ácido fólico (0,011μmol/g de peso corporal) foi administrada imediatamente antes do procedimento de HI e, após, diariamente até o 30 ou 40 DPN. No experimento 1 investigamos os efeitos do tratamento com AF sobre o comportamento motor, memória aversiva e atividade da enzima Na+,K+-ATPase. Os resultados demonstraram um efeito ansiogênico nos animais HI visto no campo aberto, prejuízo na memória aversiva no teste de esquiva inibitória e ainda diminuição na atividade da enzima Na+,K+-ATPase. No entanto, os animais HI tratados com ácido fólico não apresentaram estes efeitos, indicando uma reversão desses achados. O experimento 2 teve como objetivo investigar se o tratamento com AF influenciaria em outro tipo de memória, como a de referência e se seria efetivo na reversão da atrofia hipocampal causada pela HI. Nossos resultados indicaram que houve prejuízo no aprendizado na tarefa do labirinto aquático de Morris nos animais HI tanto na memória de referência quanto na memória de trabalho. Também, houve diminuição do volume hipocampal e área estriatal nesses animais. Todavia, observamos significativa melhora no quadro de atrofia hipocampal nos animais tratados com AF. Portanto, esses dados demonstram que o tratamento com ácido fólico desempenha um papel relevante na reversão do efeito ansiogênico, do déficit na memória aversiva, na prevenção da inibição da atividade da Na+,K+,ATPase e recuperação do volume hipocampal ocasionados pela HI neonatal. / Perinatal hypoxic-ischemic (HI) is a significant cause of mortality and morbidity in infants and young children. Folic acid is a water soluble vitamin that can be obtained through diet and has been related to the antioxidant effect, protecting ischemic events and Alzheimer's disease. The aim of this study was to investigate the role of the folic acid treatment over the behavioral, biochemical and morphologic alterations in animals submitted to neonatal HI model. Four groups of seven days-old Wistar rats, of both sexes, were used in the experiments: 1) control group treated with saline 0.9% (CT-S); 2) control group treated with folic acid (CT-FA); 3) HI group treated with saline 0.9% (HI-S); 4) HI group treated with folic acid (HI-FA). Folic acid was intraperitoneal administrated (0.011μmol/g of body weight) once before HI procedure and injections were repeated daily until the 30th or 40th postnatal day. Results were obtained from two experiments. In the first, it was investigated the effects of the FA treatment on motor performance, aversive memory and enzymatic Na+,K+-ATPase activity. Rats submitted to HI demonstrated an ansiogenic effect in the open field task, impairment in the aversive memory during avoidance test and reduction in the Na+,K+-ATPase activity. Nevertheless, when treated with folic acid, all symptoms were reverted, as observed in the animal group HI treated with folic acid. The second experiment investigated the influence of the folic acid treatment in the spatial memory, working memory and recovery of hippocampus atrophy caused by HI. Results showed impairment in the learning task during Morris’ water maze and reduction in hippocampus volume and area striatal due to HI. Folic acid treatment until the 40th postnatal day was able to reverse significantly the hippocampus atrophy. Therefore, these results demonstrate that folic acid play an important role in the recovery of the ansiogenic effect, aversive memory impairment, hippocampus atrophy and Na+,K+-ATPase activity inhibition caused by neonatal HI.
167

Efeitos da administração de ácido fólico sobre parâmetros comportamentais, bioquímicos e morfológicos em ratos submetidos à hipóxia-isquemia encefálica neonatal

Carletti, Jaqueline Vieira January 2012 (has links)
Estudos com animais submetidos ao modelo de hipóxia-isquemia (HI) neonatal reproduzem achados observados em humanos, tais como transtornos de aprendizado, comprometimento tecidual nervoso e alterações bioquímicas. O ácido fólico (AF), uma vitamina que pode ser obtida diretamente da dieta, tem sido relacionado à prevenção de eventos isquêmicos, e a proteção antioxidante. O objetivo deste estudo foi investigar o papel do tratamento com ácido fólico sobre parâmetros comportamentais, bioquímicos e morfológicos de animais submetidos à HI. Foram utilizados ratos Wistar de ambos os sexos com sete dias pós-natal (DPN) divididos em quatro grupos: 1) grupo controle tratado com salina 0,9% (CTS); 2) grupo controle tratado com ácido fólico (CTAF); 3) grupo HI tratado com salina 0,9% (HIS); 4) grupo HI tratado com ácido fólico (HIAF). Uma dose intraperitoneal de ácido fólico (0,011μmol/g de peso corporal) foi administrada imediatamente antes do procedimento de HI e, após, diariamente até o 30 ou 40 DPN. No experimento 1 investigamos os efeitos do tratamento com AF sobre o comportamento motor, memória aversiva e atividade da enzima Na+,K+-ATPase. Os resultados demonstraram um efeito ansiogênico nos animais HI visto no campo aberto, prejuízo na memória aversiva no teste de esquiva inibitória e ainda diminuição na atividade da enzima Na+,K+-ATPase. No entanto, os animais HI tratados com ácido fólico não apresentaram estes efeitos, indicando uma reversão desses achados. O experimento 2 teve como objetivo investigar se o tratamento com AF influenciaria em outro tipo de memória, como a de referência e se seria efetivo na reversão da atrofia hipocampal causada pela HI. Nossos resultados indicaram que houve prejuízo no aprendizado na tarefa do labirinto aquático de Morris nos animais HI tanto na memória de referência quanto na memória de trabalho. Também, houve diminuição do volume hipocampal e área estriatal nesses animais. Todavia, observamos significativa melhora no quadro de atrofia hipocampal nos animais tratados com AF. Portanto, esses dados demonstram que o tratamento com ácido fólico desempenha um papel relevante na reversão do efeito ansiogênico, do déficit na memória aversiva, na prevenção da inibição da atividade da Na+,K+,ATPase e recuperação do volume hipocampal ocasionados pela HI neonatal. / Perinatal hypoxic-ischemic (HI) is a significant cause of mortality and morbidity in infants and young children. Folic acid is a water soluble vitamin that can be obtained through diet and has been related to the antioxidant effect, protecting ischemic events and Alzheimer's disease. The aim of this study was to investigate the role of the folic acid treatment over the behavioral, biochemical and morphologic alterations in animals submitted to neonatal HI model. Four groups of seven days-old Wistar rats, of both sexes, were used in the experiments: 1) control group treated with saline 0.9% (CT-S); 2) control group treated with folic acid (CT-FA); 3) HI group treated with saline 0.9% (HI-S); 4) HI group treated with folic acid (HI-FA). Folic acid was intraperitoneal administrated (0.011μmol/g of body weight) once before HI procedure and injections were repeated daily until the 30th or 40th postnatal day. Results were obtained from two experiments. In the first, it was investigated the effects of the FA treatment on motor performance, aversive memory and enzymatic Na+,K+-ATPase activity. Rats submitted to HI demonstrated an ansiogenic effect in the open field task, impairment in the aversive memory during avoidance test and reduction in the Na+,K+-ATPase activity. Nevertheless, when treated with folic acid, all symptoms were reverted, as observed in the animal group HI treated with folic acid. The second experiment investigated the influence of the folic acid treatment in the spatial memory, working memory and recovery of hippocampus atrophy caused by HI. Results showed impairment in the learning task during Morris’ water maze and reduction in hippocampus volume and area striatal due to HI. Folic acid treatment until the 40th postnatal day was able to reverse significantly the hippocampus atrophy. Therefore, these results demonstrate that folic acid play an important role in the recovery of the ansiogenic effect, aversive memory impairment, hippocampus atrophy and Na+,K+-ATPase activity inhibition caused by neonatal HI.
168

Efeitos da administração de ácido fólico sobre parâmetros comportamentais, bioquímicos e morfológicos em ratos submetidos à hipóxia-isquemia encefálica neonatal

Carletti, Jaqueline Vieira January 2012 (has links)
Estudos com animais submetidos ao modelo de hipóxia-isquemia (HI) neonatal reproduzem achados observados em humanos, tais como transtornos de aprendizado, comprometimento tecidual nervoso e alterações bioquímicas. O ácido fólico (AF), uma vitamina que pode ser obtida diretamente da dieta, tem sido relacionado à prevenção de eventos isquêmicos, e a proteção antioxidante. O objetivo deste estudo foi investigar o papel do tratamento com ácido fólico sobre parâmetros comportamentais, bioquímicos e morfológicos de animais submetidos à HI. Foram utilizados ratos Wistar de ambos os sexos com sete dias pós-natal (DPN) divididos em quatro grupos: 1) grupo controle tratado com salina 0,9% (CTS); 2) grupo controle tratado com ácido fólico (CTAF); 3) grupo HI tratado com salina 0,9% (HIS); 4) grupo HI tratado com ácido fólico (HIAF). Uma dose intraperitoneal de ácido fólico (0,011μmol/g de peso corporal) foi administrada imediatamente antes do procedimento de HI e, após, diariamente até o 30 ou 40 DPN. No experimento 1 investigamos os efeitos do tratamento com AF sobre o comportamento motor, memória aversiva e atividade da enzima Na+,K+-ATPase. Os resultados demonstraram um efeito ansiogênico nos animais HI visto no campo aberto, prejuízo na memória aversiva no teste de esquiva inibitória e ainda diminuição na atividade da enzima Na+,K+-ATPase. No entanto, os animais HI tratados com ácido fólico não apresentaram estes efeitos, indicando uma reversão desses achados. O experimento 2 teve como objetivo investigar se o tratamento com AF influenciaria em outro tipo de memória, como a de referência e se seria efetivo na reversão da atrofia hipocampal causada pela HI. Nossos resultados indicaram que houve prejuízo no aprendizado na tarefa do labirinto aquático de Morris nos animais HI tanto na memória de referência quanto na memória de trabalho. Também, houve diminuição do volume hipocampal e área estriatal nesses animais. Todavia, observamos significativa melhora no quadro de atrofia hipocampal nos animais tratados com AF. Portanto, esses dados demonstram que o tratamento com ácido fólico desempenha um papel relevante na reversão do efeito ansiogênico, do déficit na memória aversiva, na prevenção da inibição da atividade da Na+,K+,ATPase e recuperação do volume hipocampal ocasionados pela HI neonatal. / Perinatal hypoxic-ischemic (HI) is a significant cause of mortality and morbidity in infants and young children. Folic acid is a water soluble vitamin that can be obtained through diet and has been related to the antioxidant effect, protecting ischemic events and Alzheimer's disease. The aim of this study was to investigate the role of the folic acid treatment over the behavioral, biochemical and morphologic alterations in animals submitted to neonatal HI model. Four groups of seven days-old Wistar rats, of both sexes, were used in the experiments: 1) control group treated with saline 0.9% (CT-S); 2) control group treated with folic acid (CT-FA); 3) HI group treated with saline 0.9% (HI-S); 4) HI group treated with folic acid (HI-FA). Folic acid was intraperitoneal administrated (0.011μmol/g of body weight) once before HI procedure and injections were repeated daily until the 30th or 40th postnatal day. Results were obtained from two experiments. In the first, it was investigated the effects of the FA treatment on motor performance, aversive memory and enzymatic Na+,K+-ATPase activity. Rats submitted to HI demonstrated an ansiogenic effect in the open field task, impairment in the aversive memory during avoidance test and reduction in the Na+,K+-ATPase activity. Nevertheless, when treated with folic acid, all symptoms were reverted, as observed in the animal group HI treated with folic acid. The second experiment investigated the influence of the folic acid treatment in the spatial memory, working memory and recovery of hippocampus atrophy caused by HI. Results showed impairment in the learning task during Morris’ water maze and reduction in hippocampus volume and area striatal due to HI. Folic acid treatment until the 40th postnatal day was able to reverse significantly the hippocampus atrophy. Therefore, these results demonstrate that folic acid play an important role in the recovery of the ansiogenic effect, aversive memory impairment, hippocampus atrophy and Na+,K+-ATPase activity inhibition caused by neonatal HI.
169

Efeito de uma dieta carente em ácidos graxos essenciais do desmame a idade adulta sobre aspectos estruturais, funcionais e moleculares renais

Maria Rolim da Paz, Andréa 31 January 2008 (has links)
Made available in DSpace on 2014-06-12T15:49:36Z (GMT). No. of bitstreams: 2 arquivo1526_1.pdf: 3081334 bytes, checksum: 9e2891701f044d8665f61bd792f09dae (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Uma dieta equilibrada deve fornecer os nutrientes necessários, inclusive os ácidos graxos essenciais (AGE) ao animal, durante toda a vida. O presente trabalho objetivou estudar aspectos funcionais, estruturais e moleculares renais em ratos no crescimento e adultos, em dieta carente em AGE (CAGE) desde o desmame. Os estudos foram realizados em gaiolas metabólicas. Os resultados, expressos como médias ± DP, foram corrigidos por 100g de peso e considerados significativos quando p0,05. Apesar de ingestão de sólido similar, os ratos CAGE pesaram menos desde a 6ª semana até adultos. A ingestão de água e a diurese foram similares entre os grupos em todas as semanas, exceto pela maior diurese dos CAGE na 7ª semana. As excreções de proteína e creatinina não diferiram entre os grupos, no crescimento e adultos. Os animais CAGE apresentaram caliurese aumentada na 7ª (616,5±135,2 vs 414,4±140,5 μmol/100g/24h) e na 8ª semana (554,7±135,1 vs 367,1±93,2 μmol/100g/24h), nesta acompanhada de maior natriurese (351,1±90,7 vs 277,4± 96,1 μmol/100g/24h), que ocorreu, também, na 13ª semana (256,8±54 vs 203,4±52,1 μmol/100g/24h) quando houve maior consumo alimentar. Na restrição hídrica de 12h, tanto os animais controles como os CAGE concentraram urina, embora estes com natriurese (223,6±16 vs 166,2±37,7 μmol/100g/12h) e caliurese (169,9±16,7 vs 126,2±22 μmol/100g/12h). Nos animais adultos, a CAGE não alterou a filtração glomerular (342,8±121,8 vs 382,9±113,1 μl/min/100g), a função tubular proximal (40±20 vs 42,5±20,9 μl/min/100g), o manuseio tubular de Na+ e a estrutura renal, esta tanto à histologia como à morfometria. Entretanto, a CAGE aumentou a atividade da Na+, K+-ATPAse e diminuiu a da Na+-ATPase, que não foi estimulada pela angiotensina II nos animais adultos. A ingestão da CAGE desde o desmame retardou o crescimento, aumentou episodicamente a excreção de Na+ e K+, sem afetar a estrutura e a função no adulto, embora tenham ocorrido alterações da atividade ATPásica no túbulo proximal renal
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Efeitos da salinidade sobre o comportamento iono-osmoregulatório e crescimento de juvenis do pampo Trachinotus marginatus

Anni, Iuri Salim Abou January 2011 (has links)
Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Aqüicultura, Instituto de Oceanografia, 2011. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2012-08-11T17:30:34Z No. of bitstreams: 1 dissertao mestrado_iuri salim abou anni.pdf: 920616 bytes, checksum: e1ed6eb173ad9593484417ec03fdce7b (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-12-19T14:26:35Z (GMT) No. of bitstreams: 1 dissertao mestrado_iuri salim abou anni.pdf: 920616 bytes, checksum: e1ed6eb173ad9593484417ec03fdce7b (MD5) / Made available in DSpace on 2012-12-19T14:26:35Z (GMT). No. of bitstreams: 1 dissertao mestrado_iuri salim abou anni.pdf: 920616 bytes, checksum: e1ed6eb173ad9593484417ec03fdce7b (MD5) Previous issue date: 2011 / O objetivo deste estudo foi avaliar os efeitos da salinidade sobre o comportamento iono e osmorregulatório, bem como o crescimento de juvenis de pampo Trachinotus marginatus. Um experimento foi realizado para estimar o ponto isosmótico e as concentrações iônicas plasmáticas do pampo. Os peixes (144,7 ± 28,4 g e 19,6 ± 2,0 cm) foram aclimatados durante quinze dias nas salinidades 4, 8, 12, 16 e 20 e amostras de sangue foram coletadas para análise da composição iônica e osmolalidade plasmática. O ponto isosmótico foi determinado pela regressão linear entre a osmolalidade plasmática e a osmolalidade da água. Em um segundo experimento, 320 peixes (2,14 ± 0,29 g e 5,11 ± 0,33 cm) foram aleatoriamente distribuídos em 16 tanques (50L). Cada tratamento foi mantido nas salinidades 3, 6, 12 e 32 (quatro repetições cada), equivalente a 25, 50, 100 e 267% do ponto de isosmótico. Durante o período experimental (28 dias), os peixes foram mantidos a 28 °C, pH 8,0, alcalinidade 135 mg CaCO3/L e saturação de oxigênio sempre superior a 90%. O consumo de oxigênio foi medido em cada salinidade. O segundo arco branquial de 12 peixes foi coletado para análise da atividade da enzima Na+/K+-ATPase. O ponto isosmótico do pampo foi determinado em 357,5 mOsmoles/kg H2O-1, o que equivale à salinidade 13,1. A osmolalidade plasmática, o hematócrito, a glicemia, o índice hepatossomático e atividade da Na+/K+-ATPase branquial não foram afetados pela salinidade. No segundo experimento, a maior taxa de consumo de oxigênio foi observado para os peixes criados na salinidade 3, enquanto a atividade da Na+/K+-ATPase branquial foi significativamente maior nesta salinidade em relação às salinidades 12 e 32. A concentração de glicogênio hepático da salinidade 3 foi significativamente menor em relação a salinidade 32. A atividade da tripsina no intestino e a umidade dos músculos não apresentaram variação significativa entre os tratamentos. O maior crescimento foi observado nas salinidades 3, 6 e 12. / The objective of this study was to evaluate the effect of salinity on juvenile growth of juvenile pompano Trachinotus marginatus. One experiment was done to estimate the isosmotic point of pompano, fish (144,7 ± 28,4 g e 19,6 ± 2,0 cm) were acclimated fortnightly at salinities 4, 8, 12, 16 and 20 and blood was sampled for osmolarity analysis. The isosmotic point was determined by linear regression between plasma osmolality and water osmolality. Later, 320 fish (2,1 ± 0,2 g and 5,1 ± 0,3 cm) were randomly distributed into 16 tanks (50L). Each treatment was maintained at salinities 3, 6, 12, and 32 (four replicates each), equivalent to 25, 50, 100 and 267% of the isosmotic point. During the experimental period (28 days), fish were maintained at 28°C, pH 8.0, alkalinity 135 mg/L of CaCO3, and oxygen saturation was always above 90%. Oxygen consumption was measured at each salinity. The second gill arch of 12 fish was collected for analysis of the Na+/K+-ATPase. The isosmotic point of T. marginatus was determined in 357,5 mOsmol/kg H2O-1, which is equivalent to salinity 13,1. Plasma osmolality, hematocrit, glycemia, hepatosomatic index and activity of Na+/K+-ATPase were not affected by salinity. In the second experiment, the highest rate of oxygen consumption was observed for fish reared at salinity 3, while the activity of Na+/K+-ATPase was significantly higher in salinity 3 in relation to salinity 12 and 32. The hepatic glycogen concentration of salinity 3 was significantly lower than the salinity 32. The activity of trypsin in the intestine and muscle humidity showed no significant variation between treatments. The best growth performance was observed at salinity 3, 6 and 12.

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