961 resultados para <C3H3O> IONS
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2010-2011 . . . .
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Vol. 3
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O presente trabalho relata os dados relativos a anlise qualitativa e quantitativa do precipitado, que se forma quando se adiciona a uma soluo contendo estrncio, dicromato de potssio, em meio amoniacal e hidroalcolico. Em lugar de se formar cromato de estrncio simples, SrCrO4, forma-se um cromato que alm do estrncio, contm os ions amnio e potssio. Solues padres contendo desde 1, 8 at 50,5 mg de estrncio, foram tratadas com soluo de dicromato de potssio 2 normal, amonaco e soluo hidroalcolica com 95% de lcool absoluto. O precipitado foi pesado e a equao de regresso que relaciona o peso do estrncio colocado e o peso do precipitado obtido, e a seguinte: Y = 4,58 X + 0, 84, onde: X o pso em miligramas, do estrncio colocado Y o pso em miligramas, do precipitado A composio provvel do precipitado parece ser 6 SrCrO4 (NH4)2 CrO4. 6K2CrO4
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The status of zinc in sugar cane, variety Co 419, troughout its life cyle, was studid in samples cut monthly, from the 6th to 15th month, from an experiment carried on under the conditions of soil and climate prevailing in Piracicaba, State of So Paulo, Brazil. The experiment consisted of 6plots, 3 fertilized and 3 unfertilized. The fertilized ones received 40 kg of N (ammonium sulfate), 100 kg P2O5 (superphosphate) and 40 kg K2O (potassium cloride) per hectare, just before planting. The zinc content was determined by the Zincon method, after separation of zinc from other ions by means of the ion Exchange Resin III, Merck. The results obtained show that there was a tendency to decrease the zinc level in the stalks, whereas it kept more or less constant in the leaves; there was an exception in January, when the zinc level in the stalks had a sharp raise: 38-90-20 and 28-60-23 ppm for the fertilized an unfertilized treatments. There was a parallelism in the absorption of zinc by the plants from 4 hills of both treatments, through the whole - plantcycle but, the total amount taken up was higher with the fertilized plot due to its greater mass production.
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O presente trabalho relata os estudos desenvolvidos sobre alguns aspectos do mtodo volumtrico de determinao do boro, solvel em cido, em fertilizantes. Foram objeto de estudos a influncia dos ions amnio e fosfato e suas consequentes eliminaes, a possibilidade da reduo da massa de manitol necessria para a titulao, face a mudana do pH do ponto final e a preciso e a exatido do mtodo. Os resultados permitiram estabelecer que 6,0 g de manitol so suficientes para a referida determinao pelo mtodo proposto. A influncia do on amnio evitada pela fervura da soluo alcalina por 30 minutos e o nion sulfato influe na precipitao do fosfato com Pb2+, sendo por isso, necessrio 1 ml da soluo de Pb (nO3)2 a 10% para cada 1% de P2O5 da amostra para a completa precipitao do fosfato. O mtodo proposto dotado de adequada preciso e exatido.
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No presente trabalho foi desenvolvida a primeira fase dos estudos experimentais do mtodo da 2,2'-dipiridil cetoxima, para a determinao do cobalto. Os ensaios foram conduzidos em solues puras e dentre os aspectos estudados constam; o reativo, preparo, concentrao e conservao; o pH, influencia sobre a formao e extrao do composto colorido; o sistema tampo, influencia sobre a reao, eficincia e escolha. Numa seqncia, sero apresentados posteriormente estudos sobre solventes, influncia de diversos ions e aplicao do mtodo em anlises de plantas.
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Estudou-se, em condies de campo, o transporte de ions NO-3 e NH+4 em uma Terra Roxa Estruturada (TE) cultivada com Vigna unguiculata (L.) Walp., quando se forneceu diferentes doses de adubo ntrico e amoniacal. O solo foi amostrado em 4 profundidades (0-20, 20-40, 40-60 e 60-80 cm), no final do ciclo vegetativo da cultura, determinando-se os teores de nitrato e amnio em cada profundidade estudada. Os teores de NO-3 aumentaram com o aumento da profundidade e das doses de N-NO-3/ha, principalmente nas doses mais altas (100, 200 e 400 kg/ha de N-N0-3). Os teores mais altos foram encontrados na profundidade de 60-80 cm sendo: 2,46; 3,72; 7,25 e 10,22 ppm de NO3, para as doses de 50, 100, 200 e 400 kg/ha de N-NO3, respectivamente. Os teores mais altos de NH+4 foram encontrados na profundidade de 0-20cm, sendo: 5,42; 7,75; 7,43 e 9,26 ppm de NH+4, para as doses de 50 , 100, 200 e 400 kg/ha de N-NH+4, respectivaimente. Observou-se menor transporte de (NH+4) em relao ao (NO-3), mesmo quando o solo recebeu as mais altas doses (kg/ha) de N-NH+4.
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Experiments for the investigation of dehydrogenase activity of washed cells of a strains of Br. abortus and another of Br. suis in presence of different single added substrates are reported. The activity was measured as the amount of formazan produced by the reduction of 2, 3, 5-triphenyltetrazolum chloride acting as a hydrogen ions acceptor, at pH 7.0. In a general manner the dehydrogenase activity of Br. suis was much more intense than that of Br. abortus (fig. 5). In the conditions of the experiments Br. abortus oxidized L-arabinose, D-galactose, D-glucose, glycerol, D-xylose, DL-alanine, D-fructose, and D-sorbitol. Brucella suis oxidized D-xylose, L-arabinose, D-glucose, D-galactose, DL-alanine, sodium acetate, maltose, glycine, D-fructose, and D-sorbitol. Glycerol was oxidized by Br. abortus but its oxidation by Br. suir was very slight. Sodium acetate and maltose were intensely oxidized by Br. suir but not by Br. abortus. The sites of more intense enzymatic acitivity were seen as small red colored round granules located in one pole of the cells.
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El present treball, com a projecte final de carrera, t com objectiu estudiar la viabilitat del suro com a material alternatiu a compostos sinttics, com per exemple bescanviadors inics convencionals. Est centrat al cas particular de la recuperaci de Palladi i Plat, metalls nobles dalt valor econmic i per tant amb un alt inters per la seva recuperaci un cop usats.
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Rsum : Les progrs techniques de la spectromtrie de masse (MS) ont contribu au rcent dveloppement de la protomique. Cette technique peut actuellement dtecter, identifier et quantifier des milliers de protines. Toutefois, elle n'est pas encore assez puissante pour fournir une analyse complte des modifications du protome corrles des phnomnes biologiques. Notre objectif tait le dveloppement d'une nouvelle stratgie pour la dtection spcifique et la quantification des variations du protome, base sur la mesure de la synthse des protines plutt que sur celle de la quantit de protines totale. Pour cela, nous volions associer le marquage puls des protines par des isotopes stables avec une mthode d'acquisition MS base sur le balayage des ions prcurseurs (precursor ion scan, ou PIS), afin de dtecter spcifiquement les protines ayant intgr les isotopes et d'estimer leur abondance par rapport aux protines non marques. Une telle approche peut identifier les protines avec les plus hauts taux de synthse dans une priode de temps donne, y compris les protines dont l'expression augmente spcifiquement suite un vnement prcis. Nous avons tout d'abord test diffrents acides amins marqus en combinaison avec des mthodes PIS spcifiques. Ces essais ont permis la dtection spcifique des protines marques. Cependant, en raison des limitations instrumentales du spectromtre de masse utilis pour les mthodes PIS, la sensibilit de cette approche s'est rvle tre infrieure une analyse non cible ralise sur un instrument plus rcent (Chapitre 2.1). Toutefois, pour l'analyse diffrentielle de deux milieux de culture conditionns par des cellules cancreuses humaines, nous avons utilis le marquage mtabolique pour distinguer les protines d'origine cellulaire des protines non marques du srum prsentes dans les milieux de culture (Chapitre 2.2). Paralllement, nous avons dvelopp une nouvelle mthode de quantification nomme IBIS, qui utilise des paires d'isotopes stables d'acides amins capables de produire des ions spcifiques qui peuvent tre utiliss pour la quantification relative. La mthode IBIS a t applique l'analyse de deux lignes cellulaires cancreuses compltement marques, mais de manire diffrencie, par des paires d'acides amins (Chapitre 2.3). Ensuite, conformment l'objectif initial de cette thse, nous avons utilis une variante pulse de l'IBIS pour dtecter des modifications du protome dans des cellules HeLa infecte par le virus humain Herpes Simplex-1 (Chapitre 2.4). Ce virus rprime la synthse des protines des cellules htes afin d'exploiter leur mcanisme de traduction pour la production massive de virions. Comme prvu, de hauts taux de synthse ont t mesurs pour les protines virales dtectes, attestant de leur haut niveau d'expression. Nous avons de plus identifi un certain nombre de protines humaines dont le rapport de synthse et de dgradation (S/D) a t modifi par l'infection virale, ce qui peut donner des indications sur les stratgies utilises par les virus pour dtourner la machinerie cellulaire. En conclusion, nous avons montr dans ce travail que le marquage mtabolique peut tre employ de faon non conventionnelle pour tudier des dimensions peu explores en protomique. Summary : In recent years major technical advancements greatly supported the development of mass spectrometry (MS)-based proteomics. Currently, this technique can efficiently detect, identify and quantify thousands of proteins. However, it is not yet sufficiently powerful to provide a comprehensive analysis of the proteome changes correlated with biological phenomena. The aim of our project was the development of ~a new strategy for the specific detection and quantification of proteom variations based on measurements of protein synthesis rather than total protein amounts. The rationale for this approach was that changes in protein synthesis more closely reflect dynamic cellular responses than changes in total protein concentrations. Our starting idea was to couple "pulsed" stable-isotope labeling of proteins with a specific MS acquisition method based on precursor ion scan (PIS), to specifically detect proteins that incorporated the label and to simultaneously estimate their abundance, relative to the unlabeled protein isoform. Such approach could highlight proteins with the highest synthesis rate in a given time frame, including proteins specifically up-regulated by a given biological stimulus. As a first step, we tested different isotope-labeled amino acids in combination with dedicated PIS methods and showed that this leads to specific detection of labeled proteins. Sensitivity, however, turned out to be lower than an untargeted analysis run on a more recent instrument, due to MS hardware limitations (Chapter 2.1). We next used metabolic labeling to distinguish the proteins of cellular origin from a high background of unlabeled (serum) proteins, for the differential analysis of two serum-containing culture media conditioned by labeled human cancer cells (Chapter 2.2). As a parallel project we developed a new quantification method (named ISIS), which uses pairs of stable-isotope labeled amino acids able to produce specific reporter ions, which can be used for relative quantification. The ISIS method was applied to the analysis of two fully, yet differentially labeled cancer cell lines, as described in Chapter 2.3. Next, in line with the original purpose of this thesis, we used a "pulsed" variant of ISIS to detect proteome changes in HeLa cells after the infection with human Herpes Simplex Virus-1 (Chapter 2.4). This virus is known to repress the synthesis of host cell proteins to exploit the translation machinery for the massive production of virions. As expected, high synthesis rates were measured for the detected viral proteins, confirming their up-regulation. Moreover, we identified a number of human proteins whose synthesis/degradation ratio (S/D) was affected by the viral infection and which could provide clues on the strategies used by the virus to hijack the cellular machinery. Overall, in this work, we showed that metabolic labeling can be employed in alternative ways to investigate poorly explored dimensions in proteomics.
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Estudi elaborat a partir duna estada a la School of Life Sciences de la University of Dundee, Gran Bretanya, entre gener i mar del 2007.L'estrs osmtic causa r pidament l'activaci de la quinasa WNK1, que fosforila i activa a continuaci les quinases SPAK i OSR1, que alhora regulen canals i transportadors dions preexistents a la membrana cellular. El factor de transcripci NFAT5 s el principal regulador de la resposta cellular transcripcional secund ria a hipertonicitat i sha descrit que les quinases p38, Fyn, PKA, ERK/MEK i ATM estan involucrades en la seva regulaci post-traduccional. No obstant, com que la funci daquestes quinases no explica totalment els mecanismes d'activaci de NFAT5, sha estudiat si lactivitat transcripcional de NFAT5 pot estar regulada per WNK1, SPAK o OSR1. Aix doncs, es va observar que lactivitat dun reporter dependent de NFAT5 no es veu afectada per la presncia de cap de les quinases anteriors, en la seva forma wild-type o dominant negatiu. Daltra banda, es va estudiar quin domini de WNK1 s necessari per a que pugui respondre a hipertonicitat i quines quinases poden estar involucrades en la fosforilaci de la serina 382 de WNK1. En conclusi, les dades obtingudes apunten que lactivaci de WNK1 en resposta a estrs osmtic requereix la seva fosforilaci en la serina 382 per quinases upstream com PAK2 o RSK i que tamb s necessari un dels seus dominis coiled-coil, almenys els amino cids 558 i 561. Aquests processos, per, semblen ser independents de lactivaci de NFAT5 en resposta a hipertonicitat.
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Rsum Le transfert du phosphate des racines vers les feuilles s'effectue par la voie du xylme. Il a t prcdemment dmontr que la protine AtPHO1 tait indispensable au transfert du phosphate dans les vaisseaux du xylme des racines chez la plante modle Arabidopsis thaliana. Le squenage et l'annotation du gnome d'Arabidopsis ont permis d'identifier dix squences prsentant un niveau de similarit significatif avec le gne AtPHO1 et constituant une nouvelle famille de gne appel la famille de AtPHO1. Base sur une tude molculaire et gntique, cette thse apporte des lments de rponse pour dterminer le rle des membres de ia famille de AtPHO1 chez Arabidopsis, inconnue ce jour. Dans un premier temps, une analyse bioinformatique des squences protiques des membres de la famille de AtPHO1 a rvl la prsence dans leur rgion N-terminale d'un domaine nomm SPX. Ce dernier est conserv parmi de nombreuses protines impliques dans l'homostasie du phosphate chez la levure, renforant ainsi l'hypothse que les membres de la famille de AtPHO1 auraient comme AtPHO1 un rle dans l'quilibre du phosphate dans la plante. En parallle, la localisation tissulaire de l'expression des gnes AtPHO dans Arabidopsis a t identifie par l'analyse de plantes transgniques exprimant le gne rapporteur uidA sous le contrle des promoteurs respectifs des gnes AtPHO. Un profil d'expression de chaque gne AtPHO au cours du dveloppement de la plante a t obtenu. Une expression prdominante au niveau des tissus vasculaires des racines, des feuilles, des tiges et des fleurs a t observe, suggrant que les gnes AtPHO pourraient avoir des fonctions redondantes au niveau du transfert de phosphate dans le cylindre vasculaire de ces diffrents organes. Toutefois, plusieurs rgions promotrices des gnes AtPHO contrlent galement un profil d'expression GUS non-vasculaire, indiquant un rle putatif des gnes AtPHO dans l'acquisition ou le recyclage de phosphate dans la plante. Dans un deuxime temps, l'analyse de l'expression des gnes AtPHO durant une carence en phosphate a tabli que seule l'expression des gnes AtPHO1, AtPHO1; H1 et AtPHO1; H10 est rgule par cette carence. Une tude approfondie de leur expression en rponse des traitements affectant l'homostasie du phosphate dans la plante a ensuite dmontr leur rgulation par diffrentes voies de signalisation. Ensuite, une analyse dtaille de la rgulation de l'expression du gne AtPHO1; H1O dans des feuilles d'Arabidopsis blesses ou dshydrates a rvl que ce gne constitue le premer gne marqueur d'une nouvelle voie de signalisation induite par l'OPDA, pas par le JA et dpendante de la protine COI1. Ces rsultats dmontrent pour la premire fois que l'OPDA et le JA peuvent activer diffrents gnes via des voies de signalisation dpendantes de COI1. Enfin, cette thse rvle l'identification d'un nouveau rle de la protine AtPHO1 dans la rgulation de l'action de l'ABA au cours des processus de fermeture stomatique et de germination des graines chez Arabidopsis. Bien que les fonctions exactes des protines AtPHO restent tre dtermines, ce travail de thse suggre leur implication dans la propagation de diffrents signaux dans la plante via la modulation du potentiel membranaire et/ou l'affectation de la composition en ions des cellules comme le font de nombreux transporteurs ou rgulateur du transport d'ions. Summary Phosphate is transferred from the roots to the shoot via the xylem. The requirement for AtPHO1 protein to transfer phosphate to the xylem vessels of the root has been previously demonstrated in Arabidopsis thaliana. The sequencing and the annotation of the Arabidopsis genome had allowed the identification of ten sequences that show a significant level of similarity with the AtPHO1 gene. These 10 genes, of unknown functions, constitute a new gene family called the AtPHO1 gene family. Based on a molecular and genetics study, this thesis reveals some information needed to understand the role of the AtPHO1 family members in the plant Arabidopsis. First, a bioinformatics study revealed that the AtPHO sequences contained, in the N-terminal hydrophilic region, a motif called SPX and conserved among multiple proteins involved in phosphate homeostasis in yeast. This finding reinforces the hypothesis that all AtPHO1 family members have, as AtPHO1, a role in phosphate homeostasis. In parallel, we identified the pattern of expression of AtPHO genes in Arabidopsis via analysis of transgenic plants expressing the uidA reporter gene under the control of respective AtPHO promoter regions. The results exhibit a predominant expression of AtPHO genes in vascular tissues of all organs of the plant, implying that these AtPHO genes could have redundant functions in the transfer of phosphate to the vascular cylinder of various organs. The GUS expression pattern for several AtPHO promoter regions was also detected in non-vascular tissue indicating a broad role of AtPHO genes in the acquisition or in the recycling of phosphate in the plant. In a second step, the analysis of the expression of AtPHO genes during phosphate starvation established that only the expression of the AtPHO1, AtPHO1; H1 and AtPHO1; H10 genes were regulated by Pi starvation. Interestingly, different signalling pathways appeared to regulate these three genes during various treatments affecting Pi homeostasis in the plant. The third chapter presents a detailed analysis of the signalling pathways regulating the expression of the AtPHO1; H10 gene in Arabidopsis leaves during wound and dehydrated stresses. Surprisingly, the expression of AtPHO1; H10 was found to be regulated by OPDA (the precursor of JA) but not by JA itself and via the COI1 protein (the central regulator of the JA signalling pathway). These results demonstrated for the first time that OPDA and JA could activate distinct genes via COI1-dependent pathways. Finally, this thesis presents the identification of a novel role of the AtPHO1 protein in the regulation of ABA action in Arabidopsis guard cells and during seed germination. Although the exact role and function of AtPHO1 still need to be determined, these last findings suggest that AtPHO1 and by extension other AtPHO proteins could mediate the propagation of various signals in the plant by modulating the membrane potential and/or by affecting cellular ion composition, as it is the case for many ion transporters or regulators of ion transport.
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Treball de recerca realitzat per un alumne densenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit cientfic del Jovent lany 2008. La nanobiotecnologia s una branca de la nanocincia i/o nanotecnologia que previsiblement tindr un gran creixement i impacte durant els propers anys en molts camps i especialment en el de la diagnosi i tractament de malalties. Aix requereix disposar de biosensors a escala nanomtrica que siguin molt sensibles i selectius enfront dagents qumics i biolgics, a fi de poder obtenir dades en temps real in situ a nivell cellular i facilitar tractaments especfics i personalitzats. Un petit pas previ als nanobiosensors sn els microsensors qumics, que poden ser fcilment implantats en teixits humans sense lesionar-los i proporcionar mesures freqents o contnues del pH o de la concentraci de diversos ions que sn dades importants per determinar lestat de salut duna persona. Els sensors ISFET tenen una configuraci que els permet detectar i mesurar les concentracions de ions H+, per tant mesuren el pH. Entre les seves aplicacions hi destaca la gran eficcia en la detecci del i H+ en petites concentracions, que, entre altres usos com els biomdics, s de gran importncia en la mesura de la qualitat dels terrenys de cultiu. Si el sensor tipus ISFET s modificat mitjanant una membrana, com es fa en el present treball, pot desenvolupar moltes aplicacions en el camp de la salut, com s el cas de la detecci de cllules mortes dins el cos hum, i per tant detectar de manera preco la necrosi.
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A Ca-stimulated ATPase activity (pH 9.5) associated with the tegumental membrane enriched (TME) fraction of Schistosoma mansoni adults was partially inhibited by NAP-taurine or by increasing concentrations of chlorpromazine; endogenous calmodulin was found associated with the TME fraction. A similar activity (pH 8.6) was histochemically visualized whithin the tegument of fixed worms on the cytoplasmic leaflet of both the doubel surface membrane and the basement membrane; this reaction was inhibited by 1 M chloropromazine and it was also observed on the inner side of double membrane vesicles present in the TME fraction. No ATPase activity could be seen at alkaline pH with added Mg or Na/K ions. Without ATP, the addition of external Ca to the fixed worms induced the appearance of lead precipitates on the tegumental discoid bodies; this reaction was inhibited by molybdate and not by chlorpromazine. The intrategumentary regulation of calcium by the systems described and the possible use of phenothiazines against schistosimes are discussed.
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Projecte de recerca elaborat a partir duna estada al Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy entre setembre i desembre 2007. Els materials monocristallins tungstats dobles de potassi i terra rara, KRE(WO4)2, a partir d'ara KREW, sn en l'actualitat un material competitiu com a material actiu per sistemes de lser d'estat slid. Aquests materials monoclnics sn fcils de dopar amb altres densitats de ions lantnid, Ln3+, i a ms presenten unes seccions eficaces d'absorci i d'emissi, molt elevades. Dins daquesta famlia, destaca el KLuW; degut als seus millors resultats com a material lser. Durant aquesta estada dun mes al laboratori Max Born de Berlin, shan realitzat les mesures de conductivitat trmica daquest material, per tal de obtenir el seu tensor de segon ordre de conductivitat trmica. El bombeig ptic dels materials lser destat slid genera calor com a resultat de la termalitzaci en els multiplets, de les relaxacions no-radiatives i de les absorcions residuals (defectes, impureses). Per tant, el coneixement de les propietats trmiques de qualsevol material actiu s essencial pel disseny de la cavitat lser i lavaluaci de la funci lser, especialment en rgims daltes potncies(...)
