The main objective of the study was to understand the mode of interaction of protamine (Ptm), a cationic antibacterial peptide from fish milt on the Gram negative bacterial envelope. The present study was designed to resolve the question of Ptm translocation across the seemingly impermeable Gram negative cell envelope. The Gram negative pathogen Pseudomonas aeruginosa was studied as an example of a microorganism that is Ptm-sensitive but doesn’t lyse even at bactericidal concentrations. Acquired resistance to Ptm was induced in P. aeruginosa by continuous sub-culturing in nutrient rich media containing increasing concentrations of Ptm. Alterations in bacterial surface charge, LPS composition, cell morphology and Ptm localisation on acquiring resistance were also examined. Expression of outer membrane proteins significantly decreased as P. aeruginosa acquired resistance to Ptm. OprF, the major porin in P. aeruginosa was found to be stably expressed in control, revertant (Ptm-Rev) and resistant (Ptm-Res) groups. No change in expression of efflux proteins was observed as a result of induced Ptm resistance, indicating that efflux is not among the Ptm resistance mechanisms at least in P. aeruginosa. OprM, which is part of the major efflux system (MexAB-OprM) in P. aeruginosa, was found to be down-regulated in Ptm-resistant P. aeruginosa. Another outer membrane protein down-regulated in Ptm-resistant P. aeruginosa was found to be petidyl-prolyl cis trans isomerase (PPIase) which plays a major role in proper folding and maturation of channel proteins in the outer membrane. Among the sarcosinate soluble proteins, DNA dependent RNA polymerase ? and ?’ subunits were found to be down-regulated in Ptm-resistant group indicating lower transcription levels in them. Lipopolysaccharide (LPS) from the three groups of P. aeruginosa under study was isolated and separated by SDS-PAGE. LPS composition of Ptm-Res P. aeruginosa was found to be significantly different from that of the control and Ptm-Rev but was found to be similar with that of LPS from O-antigenic mutant (A+B-, which possessed only A band structures). Comparison of the zetapotential of control, Ptm-Rev and Ptm-Res P. aeruginosa, proved that electrostatic shielding was coincidental in acquired resistance to Ptm in P. aeruginosa. The MIC of the parent strain of P. aeruginosa (A+B+) and the O-antigenic mutants (A+B-, A-B+ and A-B-) were found to be the same which may be indicating that alterations in O-antigenic components alone cannot contribute to Ptm resistance. Effects of Ptm treatment on morphologies of E. coli, S. typhimurium and P. aeruginosa whole cells and spheroplasts were also studied using transmission immuno-electron microscopy. Condensation of cytoplasmic contents was observed when whole cells and spheroplasts were treated with Ptm. Also, Ptm-treated cells and spheroplasts were stained with colloidal gold-labelled antibodies against Ptm to determine distribution within the target cells. It was quite evident that Ptm internalised in whole cells and spheroplasts without lysis and was found to be concentrated in the cytoplasm. Morphological changes observed in Ptm-Rev P. aeruginosa when exposed to Ptm were comparable with that of the control. Condensation of cytoplasmic contents was not observed in Ptm-Res P. aeruginosa when challenged with Ptm. Most of the Ptm was localized at or near the outer membrane of Ptm-treated Ptm-Res P. aeruginosa, indicating decreased outer membrane permeability. Results obtained from these experiments confirm that the resistance to Ptm observed in P. aeruginosa is at the very least, coincidental with the pleiotropic mutations involving change in outer surface including change in LPS composition, loss of porins and or alterations of porin size in OprF.

In this thesis we propose three new word association measures for multi-word term extraction. We combine these association measures with LocalMaxs algorithm in our extraction model and compare the results of different multi-word term extraction methods. Our approach is language and domain independent and requires no training data. It can be applied to such tasks as text summarization, information retrieval, and document classification. We further explore the potential of using multi-word terms as an effective representation for general web-page summarization. We extract multi-word terms from human written summaries in a large collection of web-pages, and generate the summaries by aligning document words with these multi-word terms. Our system applies machine translation technology to learn the aligning process from a training set and focuses on selecting high quality multi-word terms from human written summaries to generate suitable results for web-page summarization.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1964. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 410-430).

Thèse (de maîtrise)--Université Laval, 2005. / Titre de l'écran-titre (visionné le 15 décembre 2005). Bibliogr.

Orientador: Pedro de Magalhães Padilha / Resumo: Devido a sua grande concentração de nutrientes, tais como proteínas, vitaminas e minerais, o peixe é considerado um dos alimentos mais saudáveis que se pode encontrar na natureza. No entanto, a ingestão de peixes é considerada a forma predominante de via de exposição do ser humano ao mercúrio (Hg), principalmente para as populações que vivem às margens dos rios, onde o peixe constitui a principal fonte de proteína. Na tentativa de elucidar os mecanismos de toxicidade das espécies mercuriais, o teor desse metal tem sido estudado intensamente pela comunidade científica nas últimas décadas em amostras de solo, sedimentos, humanos e peixes na Amazônia brasileira. Sabe-se que as espécies mercuriais bioacumuladas nos tecidos dos seres vivos ligam-se a metaloproteínas, e quando há uma concentração alta de metal tóxico nos organismos, esses passam a expressar proteínas de defesa, denominadas metalotioneínas (MTs) responsáveis pelo transporte e eliminação de metais tóxicos. Apesar de estudos mostrarem o aumento das metalotioneínas em animais expostos a metais potencialmente tóxicos, essas proteínas não foram caracterizadas para confirmação de sua veridicidade, são analisadas por métodos indiretos, esse fato leva a necessidade de técnicas mais precisas na identificação de metalotioneínas. Levando em consideração o exposto esse estudo teve como objetivo otimizar métodos de quantificação de mercúrio e técnica de eletroforese para identificação de possíveis metalotioneínas biomarcadoras d... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Due to its high concentration of nutrients, such as proteins, vitamins and minerals, fish is considered one of the healthiest foods that one can find in nature. However, fish intake is considered to be the predominant human exposure pathway to mercury (Hg), especially for populations living along riverbanks where fish are the main source of protein. In the attempt to elucidate the toxicity mechanisms of mercurial species, the content of this metal has been intensively studied by the scientific community in recent decades in soil, sediment, human and fish samples in the Brazilian Amazon. It is known that mercurial species bioaccumulated in the tissues of living beings bind to metalloproteins, and when there is a high concentration of toxic metal in organisms, they begin to express defense proteins, called metallothioneins (MTs) responsible for the transport and elimination of Toxic metals. Although studies have shown the increase of metallothioneins in animals exposed to potentially toxic metals, these proteins have not been characterized to confirm their veridicity, are analyzed by indirect methods, this fact leads to the need for more precise techniques in the identification of metallothioneins. Taking into account the above, this study aimed to optimize mercury quantification methods and electrophoresis technique for identification of possible mercury biomarkers metallothionein in muscular and hepatic tissue of fish of economic interest, Tucunaré (Cichla spp.), Filhote (Bra... (Complete abstract click electronic access below) / Doutor

Philosophiae Doctor - PhD (Biotechnology) / High temperature stress is synonymous with the attenuation of plant growth, metabolism and eventually death resulting in major loss of crop productivity worldwide. Part of the metabolic perturbations associated with heat stress leads to the excessive formation of reactive oxygen species (ROS), which have highly deleterious effects on cellular homeostasis. Naturally, through millions of years of evolution and adjustment, plants have developed antioxidant enzymes that neutralize harmful ROS species offering a protective role in the annulment of oxidative damage in response to high temperature. The aim of this study was to measure the activity of several antioxidant enzymes in response to heat stress in Zea mays.

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Webbspel blir allt populärare. Gävleföretaget Extrude Interactive AB hade sedan en tid tillbaka planer på att lansera en spelsajt i nöjessyfte men även i syfte att marknadsföra företagets egenproducerade webbspel. Företaget hade redan en registrerad domän: spelaspel.nu. I denna rapport redovisas utvecklingsarbetet som ledde fram till den färdiga produkten som blev en färdigställd webbplats tänkt att publiceras under domänen spelaspel.nu. Webbplatsen använder sig av en SQL-databas och har utvecklats på Microsofts ramverk .NET Framework 2.0. Webbplatsen programmerades i C#, HTML och JavaScipt.

Made available in DSpace on 2014-06-12T18:07:42Z (GMT). No. of bitstreams: 2 arquivo785_1.pdf: 5265393 bytes, checksum: 53f0041ef3eeb76392e1850d05f10e31 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2010 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / O aumento da produção de cana-de-açúcar, decorrente da crescente demanda por etanol e biocombustíveis, implica na necessidade de obter variedades mais produtivas e adaptadas a fatores ambientais limitantes, como a seca. Assim, torna-se necessário o conhecimento dos genes e proteínas cuja expressão pode ser útil ao melhoramento genético. Este trabalho objetivou a identificação de peptídeos produzidos diferencialmente em resposta potencial ao estresse hídrico nos híbridos comerciais: RB867515 (tolerante à seca) e RB72454 (sensível à seca), através de análise proteômica. Proteínas totais de folha e entrenó imaturo das variedades sob irrigação ou seca foram separadas por 2D-PAGE e analisadas via espectrometria de massas. Foram identificadas várias proteínas associadas a mecanismos de resposta ao estresse hídrico, entre elas: proteínas associadas à regulação da transcrição (proteína de ligação ao RNA rica em glicina) e à tradução (fator de enlongação 1 alfa e proteína ribossômica 60S L30); componentes estruturais (histona H2A.2.2); proteínas relacionadas aos componentes do citoesqueleto (fator de despolimerização da actina 3); quinases (nucleosídeo-difosfato quinase I); enzimas envolvidas no metabolismo da glicose (gliceraldeído-3-fosfato desidrogenase, citossólica); várias proteínas do choque térmico (HSP70kDa, 17.5kDa classe II, 81-1 e 18.0kDa); e proteínas associadas à fotossíntese (complexo de evolução do oxigênio 1-1; subunidade N do centro de reação do FSI). Estas proteínas podem ser úteis como alvos potenciais para o melhoramento genético e desenvolvimento de marcadores funcionais para seleção de genótipos de cana-de-açúcar tolerantes à seca

Denna rapport är resultatet av ett tio veckors långt examensarbete med fokus på området sökmotoroptimering. Arbetet utgörs av en kombination av litteraturstudier och praktisk tillämpning. Syftet var att undersöka om det är möjligt att påverka en webbsidas ranking på Google positivt med enbart on page-metoder, det vill säga genom förändringar på den aktuella webbplatsen. Det praktiska arbetet har utförts på Rabble Communications AB, där fem av deras webbsidor utgör undersökningsobjekt. De teorier och riktlinjer som samlats in under litteraturstudien har applicerats på dessa sidor för att verifiera dess effektivitet samt för att se om det går att se resultat snabbare än vad tidigare forskning säger. Resultaten pekar på att det går att nå högre placeringar på Google genom enbart on page-metoder, dessutom inom tidsramen för detta examensarbete.