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1
Dalgleish, Pamela Weir. "The yeast maltose transporter". Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/678.
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Laba, Marija. "Optimalizace metody HPLC-ELSD pro stanovení sacharidů v potravinách". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-295706.
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This master's thesis deals with the optimalization of HPLC-ELSD method for the determination of carbohydrates in food. The theoretical part focuses on the classification and characterization of carbohydrates, the occurrence of carbohydrates in food and their physiological importance. There was targeted mainly glucose, fructose, sucrose and maltose. There is a brief summary of the analytical methods that can be used to determine carbohydrates. Experimental part is based on a literary review. It also deals with high performance liquid chromatography with evaporative light scattering detector. The main content in this part is the optimalization of condition for reliable and rapid separation of the most frequently occurring carbohydrates in foods. The carbohydrates were identified and quantified under optimum condition in real samples specifically in fruit juice, beer, ketchup and red pepper powder. The result is commented in conclusion.
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Luo, Xing. "Roles of regulatory RNAs in Vibrio pathogenic to species of aquaculture interest". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS226.
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Les petits ARN régulateurs bactériens, généralement de 50 à 300 nt de long, agissent en appariant les bases avec des cibles d'ARNm spécifiques, affectant ainsi leur traduction et/ou leur stabilité, sont des éléments importants qui régulent divers processus. V. tasmaniensis LGP32 est un pathogène de l'huître facultatif. Un ARNs Vsr217 s'est révélé être conservé dans les vibrions et fortement régulé à la hausse lors de l'infection des huîtres. J'ai trouvé que vsr217 et le gène en aval malK (codant pour une sous-unité du transporteur principal de maltose) sont tous deux exprimés à partir d'un promoteur en amont régulé par l'activateur de maltose MalT, Vsr217 étant généré à partir de la longue 5' UTR de l'ARNm de malK. Outre un effet cis sur l’expression du malK, qui diminue chez le mutant Δvsr217, nous avons constaté que l’absence de cet ARNs entraînait, lors de la croissance de cellules dans du maltose, l’augmentation de deux enzymes importantes impliquées dans la voie de la glycolyse/néoglucogenèse, Fbp et PpsA et cet ARNm de fbp étaient une cible directe de Vsr217. J'ai également exploré la régulation de la biosynthèse des acides aminés à chaîne ramifiée (BCAA: Leucine, Valine et Isoleucine) chez V. alginolyticus, un agent pathogène des poissons et mollusques et des poissons de mer et un agent pathogène humain émergent opportuniste. Nous avons constaté que l'opéron ilvGMEDA (codant la voie principale pour la biosynthèse des BCAAs) est régulé par un peptide leader traduit. Ainsi, la traduction d'un peptide riche en BCAA codé en amont des gènes de structure fournit une réponse adaptative par un mécanisme similaire au modèle canonique de E. coli. Cette étude portant sur un organisme non modèle à Gram-négatif met en évidence la conservation mécanistique de l'atténuation de la transcription malgré l'absence de conservation de la séquence primaireBacterial regulatory small RNAs, usually 50-300 nt long, act by base-pairing with specific mRNA targets, affecting their translation and/or stability, are important elements which regulate a variety of processes. V. tasmaniensis LGP32 is a facultative oyster pathogen. A sRNA Vsr217 was found to be conserved within vibrios and highly upregulated during oyster infection. I found that vsr217 and the downstream gene malK (encoding a subunit of the major maltose transporter) are both expressed from an upstream promoter regulated by the maltose activator MalT with Vsr217 being generated from the long 5' UTR of the malK mRNA. Beside a cis-effect on malK expression, which decreases in the Δvsr217 mutant, we found that the absence of this sRNA resulted, when cells grown in maltose, in the increase of two important enzymes involved in the glycolysis/neoglucogenesis pathway, Fbp and PpsA and that fbp mRNA was a direct target of Vsr217. I also explored the regulation of the biosynthesis of branched-chain amino acids (BCAAs: Leucine, Valine and Isoleucine) in V. alginolyticus, a marine fish and shellfish pathogen and an emerging opportunistic human pathogen. We found that the ilvGMEDA operon (encoding the main pathway for biosynthesis of BCAAs) is regulated by a translated leader peptide. Thus, the translation of a BCAA rich peptide encoded upstream of the structural genes provides an adaptive response by a mechanism similar to the E. coli canonical model. This study with a non-model Gram-negative organism highlights the mechanistic conservation of transcription attenuation despite the absence of primary sequence conservation
4
Yip, Hopi. "Genetic manipulation of baker's yeast for improved maltose utilisation /". [Richmond, N.S.W.] : Centre for Biostructural and Biomolecular Resarch, Faculty of Science and Technolocy, University of Western Sydney, Hawkesbury, 1999. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030625.100807/index.html.
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Schönert, Stefan. "Maltose- und Maltodextrin-Verwertung in Bacillus subtilis". [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973091967.
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Bao, Huan. "The regulatory mechanisms of the maltose transporter". Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46285.
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ATP-binding cassette (ABC) transporters couple ATP hydrolysis to import and export of a large array of substances across cell membranes in all kingdoms of life. Since the transport reaction consumes cellular energy, substrate translocation mediated by ABC transporters must be regulated according to the requirements of the cell. This thesis uses the Escherichia coli maltose transporter MalFGK2 to understand the regulatory mechanisms of ABC importers. Biochemical and biophysical approaches were employed to investigate how this transport process is modulated by maltose, the maltose-binding protein MalE and the glucose-specific enzyme EIIAGlc. First, I show that ATP facilitates MalE binding to MalFGK2, which forms the complex of MalE-MalFGK2 for efficient maltose transport. In addition, when the external maltose level exceeds that required, maltose is able to limit the maximal transport rate by promoting dissociation of MalE from MalFGK2. Finally, I find that the N-terminal tail of EIIAGlc and acidic phospholipids are essential for the binding of the protein to the MalK dimer, so that cleavage of ATP by MalFGK2 is inhibited. These results, combined with previous genetic, biochemical and structural work, provide valuable insights into our understanding of the regulatory mechanisms of the maltose transport system.
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Hamid, Mas Rina Wati Haji Abdul. "Maltose metabolism in Bacillus licheniformis NCIB 6346". Thesis, Heriot-Watt University, 1992. http://hdl.handle.net/10399/801.
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Hollingsworth, Kristian. "The synthesis of a maltose responsive switch". Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/12160/.
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A cells interaction with its surroundings is governed by the flora of the cell surface. This complex landscape of structures provides an opportunity for the re-engineering of the surface and so the cells properties without the use of genetic modification. Applying the principles of supramolecular chemistry; surface proteins can be targeted with carbohydrate based ligands to form both stable and metabolite-responsive non-covalent complexes. This redecoration of the surfaces of bacteria will make it possible to control the interactions that a bacterium makes with its environment, whether in a patient or a bioreactor. In this project the transport protein maltoporin and maltose binding protein (MBP) will be utilised in the construction of a maltose responsive switch. Both proteins will be targeted with a maltose-based polymer which can thread through maltoporin on the cell surface to interact with MBP in the periplasm. In addition, the synthesis of molecules to probe the binding of maltoporin through biophysical experiments will be investigated.
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Yip, Hopi, of Western Sydney Hawkesbury University e Faculty of Science and Technology. "Genetic manipulation of baker's yeast for improved maltose utilisation". THESIS_FSTA_SFS_Yip_H.xml, 1999. http://handle.uws.edu.au:8081/1959.7/223.
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Two yeast/E.coli shuttle vector plasmids were studied in 1994, termed pIBIDB and pBP33. According to this study, each plasmid should contain at least one ADH2UAS (upstream activation sequence in the alcohol dehydrogenase 2 gene) insert. In the present study, the constructed plasmids were analysed and transformed into laboratory strain yeast. The aim of this project was to identify the orientation, quantity and quality of the insert in the selected plasmids. Methods such as restriction analysis, polymerase chained reaction (PCR), sequencing, plate assays and enzyme assays were used to identify and evaluate the novel inserts. The data presented in this thesis suggest the inserted ADH2UAS fragment did enhance the production of maltose permease and maltase when the transformants were cultivated in maltose and ethanol-glycerol medium. The results suggested that transformants containing two inserts of ADH2UAS had a greater influence on the transformants than a single insert. But the inserts within the vectors and in transformed laboratory stain yeast appeared unstable. This could be due to the method used for plasmid construction and the storage condition of the transformantsMaster of Science (Hons)
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Scott, Peter. "The metabolism of sucrose and maltose by barley microspores". Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239199.
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Jensen, Ulla Helene. "Studies on the properties of the yeast maltose transporter". Thesis, Heriot-Watt University, 1998. http://hdl.handle.net/10399/627.
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Yip, Hopi. "Genetic manipulation of baker's yeast for improved maltose utilisation". Thesis, [Richmond, N.S.W.] : Centre for Biostructural and Biomolecular Resarch, Faculty of Science and Technolocy, University of Western Sydney, Hawkesbury, 1999. http://handle.uws.edu.au:8081/1959.7/223.
Texto completo da fonteResumo:
Two yeast/E.coli shuttle vector plasmids were studied in 1994, termed pIBIDB and pBP33. According to this study, each plasmid should contain at least one ADH2UAS (upstream activation sequence in the alcohol dehydrogenase 2 gene) insert. In the present study, the constructed plasmids were analysed and transformed into laboratory strain yeast. The aim of this project was to identify the orientation, quantity and quality of the insert in the selected plasmids. Methods such as restriction analysis, polymerase chained reaction (PCR), sequencing, plate assays and enzyme assays were used to identify and evaluate the novel inserts. The data presented in this thesis suggest the inserted ADH2UAS fragment did enhance the production of maltose permease and maltase when the transformants were cultivated in maltose and ethanol-glycerol medium. The results suggested that transformants containing two inserts of ADH2UAS had a greater influence on the transformants than a single insert. But the inserts within the vectors and in transformed laboratory stain yeast appeared unstable. This could be due to the method used for plasmid construction and the storage condition of the transformants
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Hollatz, Cláudia. "Análise da fermentação de maltose e maltotriose por saccharomyces cerevisiae". Florianópolis, SC, 2004. http://repositorio.ufsc.br/xmlui/handle/123456789/87074.
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A fermentação da maltose e maltotriose por Saccharomyces cerevisiae é de fundamental importância para diversas aplicações industriais desta levedura. No presente trabalho foi analisado aspectos do metabolismo destes açúcares relevantes para os processos de panificação e cervejaria. Por exemplo, células de leveduras continuam fermentando a massa do pão mesmo quando submetidas a refrigeração, sendo esta uma característica indesejável nas cepas de panificação. Uma vez que a maltose é o principal açúcar encontrado na massa do pão, a influência do frio (10ºC) na fermentação deste açúcar foi analisada em uma cepa selvagem de S. cerevisiae, e numa cepa csf1. mutante incapaz de transportar glicose e leucina a baixas temperaturas. A baixa temperatura afeta a cinética da fermentação por diminuir a velocidade de crescimento e rendimento celular final, com quase nenhum etanol produzido a partir de maltose pelas células selvagens a 10oC. A cepa csf1. foi incapaz de crescer em maltose a 10oC, indicando que o gene CSF1 é também necessário para a utilização de maltose a baixas temperaturas. Entretanto, o mutante csf1. também mostrou inibição acentuada da fermentação de glicose e maltose por estresse salino, além de uma significativa sensibilidade a uma série de compostos tóxicos, incluindo higromicina B, Ca2+, tetrametilamônio e pH ácido, mas não a altas concentrações de K+. Estes resultados indicam que o gene CSF1 estaria também envolvido na regulação de outros processos fisiológicos, incluindo a homeostase iônica. Em cervejaria a otimização do processo fermentativo depende da eficiente utilização de maltose e maltotriose pelas células de S. cerevisiae. Entretanto, as leveduras têm dificuldade de fermentar a maltotriose, e a incompleta utilização deste açúcar resulta, por exemplo, em uma cerveja de baixa qualidade, com um elevado extrato filtrável e sabor atípico. Para tentar compreender melhor a metabolização da maltotriose, a utilização deste açúcar foi analisada em cepas de S. cerevisiae com genótipos definidos e deletadas, ou não, em permeases específicas. A cepa selvagem analisada cresce lentamente em maltotriose, somente após uma extensa fase lag, sem produzir etanol durante o crescimento. Este fenótipo (crescimento lento e não fermentativo) não foi alterado pela deleção do gene AGT1, indicando que outro(s) transportador(es) estaria(m) provavelmente envolvido(s) na lenta utilização da maltotriose. Por outro lado uma cepa deletada nos transportadores de hexoses (hxt1-7. gal2.) fermentou eficientemente a maltotriose, mas quando o gene AGT1 foi deletado do genoma a cepa voltou a respirar este açúcar, indicando que a permease codificada pelo AGT1 é fundamental para a fermentação da maltotriose. Uma vez que a expressão constitutiva dos genes MAL é uma característica altamente desejável em cepas de panificação e cervejaria, decidiu-se analisar a contribuição que um gene regulador constitutivo teria na fermentação da maltotriose. Enquanto que algumas cepas MAL constitutivas foram capazes de fermentar eficientemente a maltotriose, a transformação de uma cepa selvagem incapaz de fermentar este açúcar com um plasmídeo contendo o gene MAL63c não melhorou a produção de etanol a partir de maltotriose. Estes resultados indicam a existência de outros fatores necessários para a eficiente fermentação de maltotriose por Saccharomyces cerevisiae. and maltotriose fermentation by Saccharomyces cerevisiae is of prime importance for several industrial applications of this yeast. In this work we have analyzed several aspects of the metabolism of these sugars relevant to the brewing and baking processes. For example, yeast cells still ferment the dough under refrigerated conditions, a characteristic highly undesirable for backing strains. Since maltose is the most abundant sugar in backing dough, we have studied the influence of cold temperature (10oC) on the fermentation of maltose by a S. cerevisiae wild-type strain, and a csf1. mutant impaired in glucose and leucine uptake at low temperatures. Cold temperature affected the fermentation kinetics by decreasing the growth rate and the final cell yield, with almost no ethanol been produced from maltose by the wild-type cells at 10oC. The csf1. strain did not grew on maltose when cultured at 10oC, indicating that the CSF1 gene is also required for maltose consumption at low temperatures. However, this mutant also showed increased inhibition of glucose and maltose fermentation under salt stress, and an increased sensitivity to several toxic compounds, including hygromycin B, Ca2+, tetramethylammonium and acidic pH, but not to high K+ concentrations. These results indicate that the CSF1 gene is probably involved in the regulation of other physiological processes, including ion homeostasis. Fermentation process optimization in the brewing industry depends on the efficient utilization of maltose and maltotriose by S. cerevisiae. However, yeasts have a difficulty to ferment maltotriose, and the incomplete utilization of this sugar results, for example, in a low quality beer with high content of fermentable sugars and atypical flavor profiles. To further understand the utilization of maltotriose, we analyzed the uptake of this sugar in yeasts strains with defined genotypes, deleted or not in specific transporters. The wild-type strain analyzed grows slowly in maltotriose, only after an extensive lag phase, and no ethanol was produce during growth. This phenotype (slow growth with no fermentation) was not affected by deletion of the AGT1 gene, indicating that probably other transporters may be involved in the slow utilization of maltotriose. On the other hand, a strain that was deleted in the hexose transporters (hxt1-7. gal2.) fermented maltotriose efficiently, but when the AGT1 gene was disrupted from the genome the strain started to respired the sugar, indicating that the AGT1 permease is required for maltotriose fermentation. Since the constitutive expression of MAL genes is a desired property of baker#s and brewery#s strains, we analyzed the contribution that a constitutive regulatory gene would have in maltotriose fermentation. While some MAL constitutive strains were capable to efficiently ferment maltotriose , the transformation of a wild-type strain incapable to ferment this sugar with a plasmid harboring the MAL63c gene did not improve ethanol production from maltotriose. These results indicate the existence of other factors required for the efficient fermentation of maltotriose by Saccharomyces.
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Day, Matthew. "Production and analysis of escherichia coli groE chaperonins". Thesis, Birkbeck (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243960.
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Machado, Fernando de Almeida. "Esvaziamento gastrico de soluções de açucares e de leite de vaca sem e com acrescimo de carboidratos em ratos adultos". [s.n.], 1995. http://repositorio.unicamp.br/jspui/handle/REPOSIP/308877.
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Orientador: Edgard Ferro CollaresTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: O presente trabalho teve como objetivo, numa primeira etapa, verificar, em ratos adultos, as retenções gástricas (RG) de soluções aqüosas de lactose, sacarose e maltose, todas na concentração a 10% (p/v), e a influência da associação combinada entre dois desses açúcares sobre o esvaziamento gástrico e, numa segunda etapa, verificar se essa influência se mantém quando se adiciona sacarose ou maltose ao leite de vaca integral. Foram utilizados 120 ratos Wistar machos com idade entre 8 a 10 semanas, que receberam suas respectivas refeições de prova por via oro gástrica, através de uma sonda metálica, no volume de 2 ml/l00 g de peso. As soluções de açúcares foram marcadas com fenol vermelho (6 mg/dl) e os leites foram marcados com PEG 4000 (2 g/dl). As RG foram determinadas calculando-se a quantidade de marcado retido no estômago, após leitura espectrofotométrica. Na primeira etapa do experimento, foram utilizados 48 animais, divididos eqüitativamente em 6 subgrupos, de acordo com a refeição de prova utilizada: lactose 10% (L), sacarose 10% (S), maltose 10% (M), lactose 5% + sacarose 5% (LS), lactose 5% + , maltose 5% (LM) e sacarose 5% + maltose 5% (SM) (p/v). A RG foi avaliada após 15 minutos da infusão orogástrica da refeição de prova. Na segunda etapa do estudo, foram utilizados 72 animais divididos em 3 subgrupos eqüitativos, de acordo com a refeição-de prova: leite de vaca integral sem acréscimo de açúcar, leite de vaca com sacarose 5% (p/v) e leite de vaca com maltose 5% (p/v). Para cada refeição de prova, foi avaliada a RG ao tempo de 15, 30 e 45 minutos, utilizando-se, em cada momento, 8 animais em cada subgrupo. Foram utilizados os testes estatísticos não paramétricos de Kruskal- W allis, com níveis de significância de 10%. Em seguida, foram feitos os testes de comparações múltiplas, com níveis de significância de 1% e 2%, respectivamente. Os resultados do estudo mostram que são significativas as diferenças entre as RG das soluções de L e M, SeM, S e SM, L e LM, L e SM. A maltose, associada à lactose ou à sacarose, promoveu retenção gástrica significativamente maior que a de solução de lactose ou sacarose isoladas, mantendo-se a densidade energética
Abstract: This study has the goals of establishing the gastric retentions of aqueous solutions of lactose, sucrose and maltose, all of them at 10% (w/v), and also the influence of associations between two of these sugars on the gastric retentions. Later on, it was studied this influence on gastric retention using sucrose or maltose on whole cow's milk. It was used 120 Wistar male rats, aged from 8 to 10 weeks. The rats received a test meal (2 rnl/l00g weight) with a marker by orogastric route through a metal tube. The markers used were phenol red (6 mg/dl) in the sugars aqueous solutions and polyethylene glycol (PEG) 4000 (2 g/dl) in the cow's milk test meal. The gastric retention was measured by determining the amount ofthe marker staying in the stomach by spectrophotometry. During the first phase of the study, 48 rats were distributed in 6 subgroups, each of them received test meal of aqueous solution of lactose 10% (L), sucrose 10% (S), maltose 10% (M), lactose 5% + sucrose 5% (LS), lactose 5% + maltose 5% (LM) and sucrose 5% + maltose 5% (SM) (w/v). The gastric retentions were determined 15 minutes after the infusion of test meal. In the second phase it was used 72 rats which were equaly distributed in 3 subgroups, according to the test meal: whole cow's milk without sugar addition, cow's milk plus suciose 5% (w/v) and cow's milk plus maltose 5% (w/v). The determinations of gastric retentions were performed at 15, 30 and 45 minutes after the orogastric infusion, being 8 animals used for each time and each test meal. In both phases of the study it was utilized the Kruskal- Wallis test, being a. = 10%. Later, the multiple comparisions were calculated with a. = 1 % and 2%, respectively, to first and second phases. There are significant differences between gastric retention of aqueous solutions of lactose and maltose (L x M), sucrose and maltose (S x M), sucrose and sucrose + maltose (S x SM), lactose and lactose + maltose (L x LM), lactose and sucrose + maltose (L x SM). The gastric retention of maltose plus lactose or maltose plus sucrose was significantly larger than those oflactose or sucrose at the same energetic density
Doutorado
Doutor em Saude da Criança e do Adolescente
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Seibold, Gerd Michael. "Charakterisierung des Glycogen- und Maltosestoffwechsels von Corynebacterium glutamicum". [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-63818.
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Shahir, Shafinaz. "Engineering and the maltose binding protein for metal ions sensing". Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434921.
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Ruzanski, Christian. "The metabolism of maltose in Arabidopsis thaliana leaves at night". Thesis, University of East Anglia, 2011. https://ueaeprints.uea.ac.uk/36357/.
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Al-Basheri, Khalid Ali. "The biochemistry and genetics of maltose metabolism in clostridium acetobutylicum". Thesis, Heriot-Watt University, 1994. http://hdl.handle.net/10399/1383.
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Liu, Mei-Ling. "Plasmid-Linked Maltose Utilization in Lactobacillus spp. Isolated from Meat". DigitalCommons@USU, 1987. https://digitalcommons.usu.edu/etd/5342.
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Five strains of Lactobacillus plantarum and four strains of Lactobacillus species isolated from fresh meat were examined for the presence of plasmid DNA. All strains examined contained between one and five plasmids ranging in molecular mass from 1.3 to 51.6 (Mdal). Plasmid-curing experiments suggest that maltose utilization is associated with a 51 Mdal plasmid in Lactobacillus sp. DB29 and 42 Mdal plasmids in Lactobacillus spp. DB27, DB28, DB31. Southern blot DNA-DNA hybridization showed homology between the maltose plasmid from Lactobacillus sp. DB29 and several plasmids from the other Lactobacillus spp.
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Rodrigues, Sueli. "Estudo da sintese enzimatica de dextrana na presença de maltose como aceptor". [s.n.], 2003. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266523.
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Orientadores: Liliane M. F. Lona, Telma F. FrancoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Doutorado
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Engström, Henrik. "Development of Flourescence-based Immunosensors for Continous Carbohydrate Monotoring : Applications for Maltose and Glucose". Doctoral thesis, Högskolan i Kalmar, Naturvetenskapliga institutionen, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hik:diva-45.
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Weak affinity interaction of monoclonal antibodies and carbohydrate antigens can be detected and quantified by alterations in the antibodies' intrinsic tryptophan fluorescence. These weak/transient binding events have been monitored by total internal reflection fluorescence (TlRF) by facilitating the change in intrinsic tryptophan fluorescence. This immunosensor followed instant changes in the antigen concentration with rapid association- and dissociation rate constants reaching equilibrium in a short time, without the need for regeneration. Furthermore, in a competition assay with extrinsic fluorescence labeling, it was established that Förster/fluorescence resonance energy transfer (FRET) can be applied for weak and transient interactions. By entrapping components in small semipermeable capsules, aconvenient flow system was fabricated allowing on-line measurements of maltose. Quantification of maltose concentration was achievable in the mM-range without need for regeneration.High specificty for maltose was exhibited in crude food-samples with quantification in accordance with batch analysis. Furthermore, a monoclonal antibody was developed for potential use as a glucose immunosensor for diabetes. Its ability to interact with glucose was determined by competitive weak affinity chromatography (WAC) to approximately 19 mM in dissociation constant. This antibody was developed to bind monosaccharides, especially glucose, by utilizing crossreation with a carbohydrate dextran polymer. Selectivity for glucose was greater than for the similar monosaccharides, mannose and galactose. This antibody, or a fragment, in a fluorescence platform is an alternative to monitor glucose in vivo where other glucose-binders might fail.Att känna igen en motståndare är viktigt i många sammanhang, inte minst i kroppens immunförsvar som är utvecklat för att angripa främmande ämnen i kroppen. Antikroppen spelar en central roll i immunförsvaret där den lär sig att känna igen sin motståndare (antigen) och därmed binda sitt antigen. De antikroppsproducerande cellerna kan användas i laboratoriet för att producera antikroppar som härstammar från försöksdjur. I denna avhandling har antikroppar använts som binder betydligt svagare till antigenet än vad man i de flesta analyser använder sig av för att t.ex. detektera sjukdomar. Antikroppar som binder till olika typer av socker, däribland maltsocker (maltos) och blodsocker (glukos) har studerats. Dessa antikroppar har använts för att undersöka hur hårt de binder till sitt antigen beroende på temperatur och om antikropparna kan känna igen liknande motståndare (korsreaktivitet). Fördelen med dessa svaga bindningar är att antikroppen snabbt kan binda in och släppa sitt antigen istället för att nästan permanent sitta på sitt antigen, som vid starka bindningar. Bindningens styrka (affinitet) har i avhandlingen studerats med hjälp av fluorescensteknik och affinitets-separation. Den maltosbindande antikroppen har använts tillsammans med fluorescensteknik för att designa två olika biosensorer (immunosensorer). Immunosensorerna kan mäta förändringen av maltoskoncentration över tid, vilket är attraktivt i t.ex. livsmedelsindustrin när man vill mäta maltoshalten kontinuerligt under tillverkningen. Den glukosbindande antikroppen har använts i affinitets-separation för att bestämma dess affinitet mot glukos och olika polymerer av glukos. En glukosbindande antikropp är åtråvärt för att t.ex. kontinuerligt mäta koncentrationen av blodsocker genom huden hos diabetiker och därmed minska antalet blodprover man idag behöver ta.
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Cerqueira, Vanessa Cassoni [UNESP]. "Produção de frutose a partir de hidrolisado enzimático de amido de mandioca". Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/101731.
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Universidade Estadual Paulista (UNESP)
Os produtos das hidrólises de amido são glicose, maltose e uma série de oligossacarídeos e polissacarídeos que encontram utilização principalmente na indústria de alimentos. Neste grupo enquadram-se os adoçantes que aditam sabores a produtos que são demandados por consumidores específicos. Atualmente o açúcar mais utilizado no Brasil é a sacarose, produto extraído da cana-de-açúcar, e o mais utilizado mundialmente é a frutose obtida a partir da hidrólise do milho e posterior isomerização da glicose para frutose. A frutose apresenta capacidade edulcorante 30% maior que a sacarose, 2,5 vezes maior que a glicose e 2 vezes mais solúvel que a glicose, com isso, pode ser utilizada em menor quantidade, diminuindo o poder calórico do alimento e viabilizando sua utilização no tratamento da obesidade. Levando em consideração a importância dos adoçantes para o mercado de alimentos, o presente trabalho teve como objetivo realizar estudos sobre o processo de obtenção da frutose a partir de amido de mandioca. Para a execução dos ensaios utilizou-se fontes comerciais de α– amilase e amiloglucosidase, Liquozyme Supra 2.2X e Saczyme 750 AGUg-1, respectivamente, aplicadas em substrato de amido de mandioca em reator agitado com temperatura controlada. Após o processo de hidrólise enzimática, o hidrolisado passou por um processo de purificação utilizando terra diatomácea e carvão ativado em quatro temperaturas (30, 40, 50 e 60°C), com a finalidade de remoção de contaminantes originários da matéria prima, que levam a odor, cor e sabores indesejáveis. Após o tratamento com carvão ativo e terra diatomácea foram realizados ensaios para estabelecer os melhores parâmetros para a realização do processo de isomerização, buscando a conversão de parte da glicose à frutose, utilizando a enzima...
The products of starch hydrolyses are glucose, maltose and a series of oligosaccharides and polysaccharides which have their main utilization in food industry. This group comprises sweeteners that add flavor to products demanded by specific consumers. Currently the most used sugar in Brazil is sucrose, a product extracted from sugarcane, while the most used sugar worldwide is fructose obtained from maize hydrolysis and subsequent glucose isomerization to fructose. The sweetening capacity of fructose is 30% higher than that of sucrose and 2.5-fold higher than that of glucose; in addition, fructose is 2-fold more soluble than glucose and thus can be used in smaller quantities, decreasing the food’s caloric potential and making its use viable in obesity treatment. Considering the importance of sweeteners for the food market, the present study aimed to investigate the process of fructose production from cassava starch. The assays were performed by using commercial sources of α–amylase and amyloglucosidase, Liquozyme Supra 2.2X and Saczyme 750 AGUg-1, respectively, applied to cassava starch substrate in an agitated reactor at controlled temperature. Following the process of enzymatic hydrolysis, the hydrolysate underwent a purification process using diatomaceous earth and activated charcoal at four temperatures (30, 40, 50 and 60°C), in order to remove contaminants originated from the raw material, which lead to undesirable smell, color and flavor. After the treatment with activated charcoal and diatomaceous earth, assays were carried out to establish the best parameters for the isomerization process, aiming at the conversion of part of glucose into fructose, using the enzyme isomerase. The process selected for the studies was in a continuous system where the glucose syrup, previously purified, was continuously pumped... (Complete abstract click electronic access below)
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Eduardo, Mariana de Paula. "Hidrólise enzimática de mandioca e puba para a obtenção de xarope de maltose". Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/11/11141/tde-07042003-142026/.
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Atualmente o consumo de xarope de maltose vem crescendo devido ao seu uso em cervejarias e está substituindo progressivamente os adjuntos amiláceos. O xarope de maltose é, tradicionalmente, produzido por meio da hidrólise ácida e/ou enzimática de amido ou flocos de milho. Este trabalho teve como objetivo analisar a possibilidade de obtenção de maltose a partir de outras matérias-primas amiláceas como a mandioca e a puba (produto derivado da fermentação da mandioca) pela ação da a-amilase bacteriana e da a-amilase fúngica sem que fosse necessária a extração do amido. Amostras de mandioca e puba com 10, 20 e 30% de sólidos foram incubadas com a-amilase bacteriana termoestável durante 10, 20 e 30 minutos a 80 0 C, adicionando-se em seguida, µ-amilase fúngica e incubando-se as amostras durante 48 horas a 55 0 C. O grau de sacarificação, expresso em dextrose equivalente (DE), foi determinado pelo método DNS em vários intervalos de tempo. Glicose e maltose foram determinadas por HPLC após 48 horas de sacarificação. Os resultados mostraram que o tempo de ação da a-amilase bacteriana não causou diferenças significativas no grau de hidrólise entre as amostras, mas a concentração de sólidos influiu significativamente no grau da liquefação das amostras. O comportamento das curvas do grau de sacarificação foi semelhante para todos os tratamentos tanto da mandioca quanto da puba. O conteúdo de maltose nas amostras variou entre 30-60% e a glicose entre 0-10% caracterizando um xarope com alto teor de maltose. A eficiência de hidrólise ficou abaixo do esperado. Entretanto, esse fato pode ser explicado pela utilização da mandioca sem extração prévia do amido e pelas dificuldades na extração dos sólidos por centrifugação. Pode-se afirmar que tanto a mandioca quanto à puba podem ser utilizadas como matéria prima em substituição ao milho na obtenção de xarope de maltose através da hidrólise enzimática. A puba, porém, é de mais fácil manuseio sendo que o tratamento com 20% de sólidos, exposto durante 10 minutos a a-amilase bacteriana proporcionou maior rendimento, atingindo 4,2 kg de maltose e 0,3 kg de glicose por 100 kg de mandioca fresca além de proporcionar menor quantidade de resíduo sólidos de 13,7 kg.Nowadays the consumption of maltose syrups is increasing due to its utilization in breweries where it replaces starch adjuncts. Traditionally maltose syrup has been produced from cornstarch or pellets using acid and/or enzymatic hydrolysis. The objective of this work was to evaluate the possibility of obtaining maltose from starch sources other than maize, such as cassava roots or puba, a fermented cassava product, without extraction of the starch, using bacterial a-amylase and fungal a-amylase for starch hydrolysis. Cassava and puba samples with 10, 20 and 30% dry matter were incubated with termostable bacterial a-amylase for 10, 20 and 30 minutes at 80 0 C, followed by the addition of fungal a-amylase. The samples were incubated for 48 hours at 55 0 C. The degree of saccharification, expressed as dextrose equivalent (DE), was determined by the DNS method. The glucose and maltose contents of the hydrolysate were determined after 48 hours by HPLC. The results showed that the time of action of a-amylase did not influence the degree of saccharification of the samples but the solids concentration significantly affected the hydrolysis degree. The saccharification degree curves were similar for both cassava and puba. The maltose content of the samples varied between 30-60% and the glucose content between 0-10%, which characterized them as "High maltose syrups". The hydrolysis efficiency was lower than expected. However, this fact could be explained by the use of cassava without extraction of the starch and by the difficulty of extracting the solids by centrifugation. It was concluded that for replacement of corn starch, both cassava roots and puba could be used as raw materials for maltose syrup production by enzymatic hydrolysis. However the puba was easier to handle than cassava. The puba treatment consisting of 20% of solids and 10 minutes exposure to a-amylase gave the highest yield reaching 4.2 kg of maltose and 0.3 kg of glucose per 100 kg of raw cassava, in addition to a lower solids residue of 13.7 kg.
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Kirsch, Monika. "Low temperature induces raffinose family oligosaccharide and maltose accumulation in plants". Göttingen Cuvillier, 2009. http://d-nb.info/999186418/04.
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Derkaoui, Meriem. "Métabolisme du carbone et virulence chez Neisseria meningitidis". Thesis, Paris, AgroParisTech, 2015. http://www.theses.fr/2015AGPT0047/document.
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Neisseria meningitidis possède un PTS incomplet. Constitué des composants générales EI et HPr et de deux EIIAs (EIIANtr et EIIAMan), ce système ne permet pas le transport des sucres chez cette bactérie. Cependant, nous avons confirmé que la cascade de phosphorylation (EI HPr EIIANtr) est fonctionnelle et que HPr est aussi phosphorylée sur sa Ser-46 par une HprK/P.Dans l’objectif d’étudier l’effet de HPr sur la virulence de N. meningitidis, nous avons construit un mutant ΔptsH chez N. meningitidis 2C4-3. Le mutant ΔptsH a montré une faible survie chez la souris, une faible production de la capsule, une meilleure adhérence aux cellules épithéliales et un niveau élevé de cellules apoptotiques, par rapport à la souche sauvage. HPr semble intervenir dans la virulence de N. meningitidis en interagissant avec la protéine CrgA. L’interaction HPr/CrgA est plus forte quand HPr est phosphorylée sur sa Ser-46 par HprK/P.N. meningitidis utilise le glucose et le maltose comme seuls sucres. Nous avons identifié une perméase à glucose (GlcP) et une perméase à maltose (MalY), responsables du transport de ces sucres. Une perméase putative à gluconate (GntP) a été également identifiée chez N. meningitidis 2C4-3. Cette perméase n’assure pas le transport du gluconate, dans les conditions testées. La délétion de gntP chez N. meningitidis 2C4-3 induit une meilleure croissance sur glucose et une bonne survie du mutant ΔgntP chez la souris, par rapport à la souche sauvage. La fonction réelle de la perméase GntP chez N. meningitidis reste inconnue et suscite des études ultérieuresNeisseria meningitidis has an incomplete PTS composed of general proteins EI and HPr and two EIIAs (EIIANtr and EIIAMan). This system does not allow the transport of sugars in this bacterium. However, we confirmed that the phosphorylation cascade (EI HPr EIIANtr) is functional and HPr is also phosphorylated at its Ser-46 by an HprK/P.In order to study the effect of HPr on meningococcal virulence, we constructed a ΔptsH mutant in N. meningitidis 2C4-3. Compared to the wild-type strain, the ΔptsH mutant showed poor survival in mice, low production of capsule, better adherence to epithelial cells and high levels of apoptotic cells. HPr appears to be involved in the virulence of N. meningitidis by interacting with CrgA protein. The HPr/CrgA interaction is stronger when HPr is phosphorylated at its Ser-46 by HprK/P.N. meningitidis uses glucose and maltose as the only sugars. We identified permeases for glucose (GlcP) and maltose (MalY), which catalyze the uptake of these sugars.A putative gluconate permease (GntP) has also been identified in N. meningitidis 2C4-3. Under the conditions tested, this permease did not catalyze the transport of gluconate. Compared to the wild-type strain, deletion of gntP in N. meningitidis 2C4-3 induced faster growth on glucose and a better survival of the mutant in mice. To underst and the function of the GntP permease in N. meningitidis further studies will have to be carried out
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Teles, Juliana Andrade. "Estudo da produção de mosto concentrado lupulado a partir de extrato de malte concentrado, xarope de alta maltose e lupulo". [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255530.
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Orientador: Roberto Herminio MorettiDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O uso de extrato de malte concentrado como matéria-prima cervejeira até hoje foi pouco estudado. É sabido que produzir cervejas claras e sem resíduo adocicado, é um desafio para este ingrediente. No entanto, cervejas produzidas a partir de extrato de malte concentrado, necessitam de menores investimentos quando se comparado ao método tradicional pois, economiza em mão-de-obra, espaço e energia. Pensando nisso, o trabalho teve como objetivo, produzir diferentes mostos concentrados lupulados formulados conforme planejamento experimental aplicado (DCCR), caracterizar as cervejas produzidas com estes mostos. Estudar o uso de xarope de alta maltose com a finalidade de redução da cor e proteína no produto final e verificar durante a fervura, interações ocorridas entre malte/adjunto, lúpulo e tempo quanto à cor, amargor, polifenóis e proteínas. Verificou-se que mostos produzidos com extrato de malte concentrado possuem fermentações mais lentas. Os produtos obtidos tiveram características físico-químicas semelhantes à cerveja tipo Pilsen. Durante a fervura, o tempo foi mais influente para a produção de cervejas mais escuras. Apesar disso, o uso de xarope de alta maltose como substituição parcial dos açúcares fermentescíveis do malte, na redução da cor, foi totalmente eficaz, como também para o aumento na luminosidade e menores quantidades de proteínas. Por fim, para promover mais eficiente complexação entre proteínas-polifenóis, seriam necessárias quantidades maiores de lúpulo. Assim sendo, mostos concentrados feitos a partir de extrato de malte concentrado possuem grandes potencialidades e levam a crer que acrescentam mais vantagens do que desvantagens para a produção de cerveja
Abstract: The use of extract malt concentrated as beer raw material until today little was studied. It is known that to produce clear beers and without sweet residue, it is a challenge for this ingredient. However, beers produced from extract malt concentrated, need lesser investments when if compared with the traditional method, therefore it is saved in man power, space and energy. Thinking about this, the work had as objective, to produce differents worts hopped concentrated formulated as experimental design applied, to characterize the beers produced with these worts, to study the use of boiled must of high maltose with the purpose of reduction of the color and protein and to verify, during the boil, occurred interactions between malt/adjunct, hop and time how much to the color, bitter taste, polyphenol and proteins. It was verified that worts produced with extract of malt concentrated have slower fermentations, the gotten products had characteristics similar to the beer Pilsen type. During the boil, the time was more important for production of darker beers. Despite this, the use of high maltose syrup as partial substitution of the fermentable sugars of malt, in the reduction of the color was total efficient, as also for the increase of the luminosity and minors amounts of protein. Finally, to promote more efficient complex between proteins-polyphenols, they would be necessary more of hop. Thus being, made intent worts from extract of malt concentrated have great potentialities and lead to believe that they add more advantages of that disadvantages for beer production
Mestrado
Mestre em Tecnologia de Alimentos
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Dodsworth, Steven James. "Cloning, sequencing and expression of the Aeromonas salmonicida maltose-inducible porin gene". Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359863.
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LEMEE, LENAICK. "Le maltose en synthese glycosidique acylation d'oligomeres de l'amylose et de l'amidon". Rennes 1, 2000. http://www.theses.fr/2000REN10095.
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L'amidon est une ressource agricole, renouvelable, bon marche et disponible en quantite importante. L'utilisation de l'amidon en tant que materiau devient un sujet d'autant plus interessant que le recyclage des matieres plastiques d'origine petrochimique reste problematique et que la demande en materiaux biodegradables augmente rapidement. L'hydrophilie naturelle de ce polysaccharide est une contrainte majeure qui limite le developpement des materiaux a base d'amidon. Une alternative consiste a utiliser des esters d'amidon moins hydrophiles mais dont la preparation necessite jusqu'ici la presence de solvant. La mise au point d'une reaction d'esterification transposable en machine selon un procede continu ou discontinu permettrait de developper l'utilisation industrielle des esters d'amidon par exemple dans le domaine de l'emballage et des polymeres biodegradables. Par ailleurs l'hydrolyse chimique et/ou enzymatique de l'amidon fournit egalement le maltose qui est un substrat de depart particulierement interessant en synthese glycosidique et qui peut etre utilise pour la preparation de molecules a haute valeur ajoutee. Dans un premier chapitre, apres une rapide mise au point sur la synthese glycosidique, nous decrivons la preparation des -maltoside et -maltotrioside de methyle ces deux oligosaccharides modeles de l'amylose ainsi que l'-d-glucopyranoside de methyle ont ensuite ete partiellement et regioselectivement acyles en utilisant une reaction de transesterification avec des esters de glycidyle ou de vinyle. La deuxieme partie de cette these est consacree a la preparation du motif trisaccharidique de l'acarbose qui est un principe actif utilise dans le traitement du diabete. Notre approche s'appuie sur une strategie 1 + 2 utilisant un donneur de fucopyranosyle et un accepteur maltosidique prepares respectivement a partir du d-galactose et du maltose. Au cours de ce travail nous avons montre les influences respectives du solvant et du groupe protecteur introduit sur la position 4 du donneur de glycosyle sur la stereoselectivite du couplage glycosidique. Enfin, au cours du troisieme chapitre, nous avons transpose les reactions d'acylation decrites dans le chapitre 1 a des polymeres synthetiques puis a l'amidon. Nous avons egalement etudie la reaction de formiatation de l'amidon et montre que certains formiates d'amidon peuvent etre utilises comme substrats des reactions de transesterification.
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Kaplan, Fatma. "Beta-amylase induction and the protective role of maltose during temperature shock". [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0008330.
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Merstorf, Céline. "Stabilité conformationnelle et dépliement de la protéine MalE : Étude par nanopore et par spectroscopie RMN". Thesis, Cergy-Pontoise, 2011. http://www.theses.fr/2011CERG0571/document.
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Nous avons étudié le couplage dépliement-transport de la Maltose Binding Protein (MBP ou MalE), une protéine périplasmique d'E. Coli et d'un mutant instable, le MalE219, en fonction de la concentration d'un agent dénaturant, le chlorure de guanidium (GdnHCl) à l'échelle de la molécule unique. La technique utilisée est basée sur la détection électrique du transport de macromolécules à travers un nanopore protéique (l'Aérolysine d'Aeromonas Hydrophila) inséré dans une bicouche lipidique plane. Les résultats obtenus ont été comparés à ceux obtenus lors d'une précédente étude réalisée à travers un autre nanopore protéique, l'alpha-hémolysine du Staphylocoque doré, de géométrie et de charge nette différente. Nous avons montré l'existence de temps courts et longs de blocage du courant associés à des protéines dépliées ou partiellement repliées. La fréquence des blocages du courant permet d'obtenir la fraction de protéine dépliée passant à travers le pore en fonction de la concentration en GdnHCl. Les courbes de dénaturation obtenues avec les deux pores montrent un comportement sigmoïdale très similaire. Le type de pore n'influence donc pas la dénaturation des protéines, mais uniquement leur dynamique de transport. En revanche, la courbe de dénaturation du mutant instable présente un déplacement vers les concentrations plus faibles en GdnHCl. Il a été montré également que la présence du maltose comme ligand sur le MalE219 stabilise nettement sa structure. Pour La MBP, les temps de blocages longs diminuent avec l'augmentation de la concentration de GdnHCl montrant une dynamique de transition vitreuse . Cette technique est appropriée à l'étude du dépliement et des changements de conformation de protéines, mais ne permet pas d'obtenir des informations structurales sur les états intermédiaires de repliement. Ainsi, la spectroscopie RMN a été utilisée pour tenter de caractériser ces états intermédiaires de repliement, notamment par la méthode d'échange proton-deutérium. Elle consiste à suivre les cinétiques d'échange des résidus de la protéine sur des spectres 2D 1H-15N HSQC à différentes concentrations de GdnHCl.Ainsi 180 résidus sur les 370 que compte la MBP ont été suivis lors de la dénaturation en présence de GdnHCl. Les deux hélices en C-terminal sont très accessibles au solvant et se dénaturent facilement. La MBP est composée de deux domaines globulaires, le domaine N-ter et le domaine C-ter. Les éléments de structures secondaires situés dans la zone intermédiaire entre les deux domaines (principalement des brins β) sont particulièrement affectés par l'agent dénaturant. D'autres structures secondaires dans les domaines globulaires sont très protégées et plutôt stables. Il est donc proposé que les protéines partiellement dépliées s'insèrent dans le pore par l'extrémité C-terminal et que des parties de structuration tertiaire restent stable entraînant le blocage du poreWe study the unfolding-transport mechanism of the Maltose Binding Protein (MBP or MalE), a periplasm protein of E. Coli and a destabilised variant, the MalE219, as the function of the concentration of denaturing agent, Guanidine Hydrochloride(GdnHCl) at the single molecule level. The technique is based on the electrical detection of the macromolecule transport through a nanometer-scale channel, Aerolysin channel, inserted into a planar lipid bilayer. Results obtained were compared to previous data with another channel, the alpha-Hemolysin. Both channels have different geometry and net charge.We show that we can distinguish unfolded states from partially folded ones with aerolysin pore.Unfolded proteins induce short current blockades, their duration is constant as a function of the concentration of denaturing agent. Partially folded proteins exhibit long blockades whose life times decrease as the concentration of GdnHCl increase, this indicates a possible glassy dynamics.The frequency of the short current blockades increases as the concentration of denaturing agent increases, following a sigmoidal denaturation curve.The unfolding curve of native MBP with Aerolysin pore is similar to the one previously measured with Hemolysin channel. The denaturation curve of the destabilized variant obtained with Aerolysin is shifted towards lower value of GdnHCl concentration in agreement with bulk measurements. We show also that the addition of maltose stabilizes the structure of MalE219. This nanopore recording technique is also suitable for the study of unfolding and conformation changes of proteins.In order to obtain structural informations that nanopore recording cannot provides, the structure of MBP along its denaturation curve was studied by NMR spectroscopy. The Hydrogen-exchange method known to be sensitive to folding intermediates was specially used. It consists in tracking hydrogen-deuterium exchange rates for amino on the 2D 1H-15N HSQC spectra.Thus, 180 residus of 370 for MBP was followed during denaturation in the presence of GdnHCl. The two last helices in C-terminal of MBP are accessible to the solvent and are denaturated easily. MBP is a two domains protein, N-ter domain and C-ter domain. It was found out that the C- and D-domain of MBP (mainly alpha-helices) could be relatively stable in presence of denaturing agent and that beta strands which make the link between the two domains would be affected by the denaturing agent. It was proposed that partially unfolded proteins enter the pore by the C-terminal end and that stable tertiary structure still present block the pore
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Zhang, Xiaochen. "The binding modes of maltose binding protein with different ligands studied by NMR". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29813.pdf.
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Zhang, Xiaochen 1969. "The binding modes of maltose binding protein with different ligands studied by NMR /". Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27438.
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Maltose Binding Protein (MBP) of Escherichia Coli, a kind of periplasmic protein, can bind its ligands interacting predominantly either with their anomeric end (end-on binding) or with the middle of the maltodextrin chain (middle binding). Using NMR spectroscopy, we have studied the modes by which maltose, linear maltodextrin and some derivatives like $ beta$-cyclodextrin bind to MBP. 1D proton difference spectra and 2D HSQC proton-nitrogen correlation spectra were acquired of MBP in the presence of different ligands. Spectra with linear maltodextrins showed many common features and were distinctly different from those of MBP with $ beta$-cyclodextrin. 2D HSQC spectra suggest further that MBP- $ beta$-cyclodextrin adopts an open form conformation similar to that of ligand free MBP because of the surprisingly similarity of their spectra. Ligands such as $ beta$-cyclodextrin, can not be transported into the cyto-plasm but have high affinity for MBP, multiple $ alpha$(1-4) linkages and no reducing end. These ligands bind to MBP mainly by the middle binding mode. This suggests that this mode determines high affinity binding of ligand to MBP, but doesn't produce a physiologically active complex.
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Greller, Gerhard. "Molekulare und biochemische Charakterisierung des Trehalose-Maltose-Transportsystems des hyperthermophilen Archaeons Thermococcus litoralis". [S.l. : s.n.], 2001. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9676828.
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Chagneau, Claudia. "Le contrôle par CRP-AMPc de l'expression du gène malT d'Escherichia coli permet d'associer la nature de la source de carbone et le pH extracellulaire". Lyon 1, 2002. http://www.theses.fr/2002LYO10205.
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Les bactéries sont capables de détecter les variations de nombreux paramètres de l'environnement et d'y répondre. Ces réponses adaptatives impliquent que les informations associées à l'environnement soient perçues par des molécules réceptrices qui génèrent un signal transmis à des régulateurs de l'expression des gènes. Une information importante pour les bactéries est le pH du milieu de culture. Chez la bactérie neutrophile Escherichia coli, plusieurs gènes ont une expression qui varie suivant la valeur du pH extracellulaire sans qu'il n'y ait de changement du pH intracellulaire. Parmi ces gènes se trouvent les gènes du régulon maltose qui codent pour des protéines impliquées dans le transport et le métabolisme du maltose et des maltodextrines. La voie de signalisation associée au pH extracellulaire et impliquée dans la régulation de l'expression du régulon maltose n'a pas été identifiée à ce jour et ce travail a eu pour objectif de contribuer à cette caractérisation. Durant cette étude, nous avons mis en évidence une relation étroite entre les mécanismes impliqués dans la transduction du signal associé au pH extracellulaire et les mécanismes mis en jeu dans l'adaptation aux sources de carbone présentes dans le milieu de culture. En effet, la régulation de l'expression du régulon maltose selon le pH dépend de la concentration de la protéine GlpK qui catalyse la phosphorylation du glycérol en glycérol-3-phosphate et nécessite la présence de glycérol dans le milieu de culture. De plus, des éléments impliqués dans la répression catabolique tels que le régulateur transcriptionnel global CRP-AMPc et la protéine IIAGlc sont nécessaires à la régulation du régulon maltose selon le pH extracellulaire. La transduction du signal généré par le pH extracellulaire modulerait d'une part la quantité de complexe CRP-AMPc en contrôlant la production d'AMPc par l'adénylate cyclase et déclencherait d'autre part, à certains pH, l'activation d'un mécanisme qui requiert la protéine IIAGlc et qui est susceptible de réprimer la transcription de certains gènes.
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Garin, Élisabeth. "Embryogenèse somatique chez le merisier (Prunus avium L. ) : étude des polyamines en relation avec l'embryogenèse". Compiègne, 1995. http://www.theses.fr/1995COMPD824.
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Chez Prunus avium, différents types d'explants ont été testés pour leur aptitude à l'embryogenèse somatique. Des embryons somatiques ont pu être formés uniquement à partir de cotylédons immatures, par voie directe ou indirecte. Lors de l'embryogenèse indirecte, nous avons observé une interaction entre la concentration en BAP et kinétine et l'origine des embryons zygotiques (arbre donneur) sur la fréquence d'explants embryogènes. Nous avons pu obtenir jusqu'à 35% de cotylédons embryogènes. La réinduction des embryons somatiques a permis d'établir des lignées embryogènes. Chaque lignée provient d'un embryon zygotique initial. Les lignées embryogènes sont entretenues sur un milieu contenant en permanence de l'ANA(0,54 uM), de la kinétine (0,46 uM) et de la BAP (0,44 uM). Par lignée embryogène, différentes générations de tissus embryogènes sont obtenues par la réinduction successive des embryons somatiques formés. Les embryons somatiques sont formés essentiellement par voie indirecte, mais également par embryogenèse secondaire. Le remplacement du saccharose par du maltose stimule l'embryogenèse secondaire et la production d'embryons somatiques par explant embryogène. L'apport de L-proline augmente l'effet du maltose sur l'embryogenèse somatique. Un effet de la nature et de la concentration en sucre ainsi qu'un effet de L-proline est observé sur la morphologie des embryons somatiques. L'apport d'un inhibiteur de biosynthèse de l'éthylène (CoC12) ou de l'action physiologique de l'éthylène (AgNO3) à différents moments lors de la réinduction des embryons somatiques affecte la fréquence d'explants embryogènes et la production d'embryons somatiques par explant embryogène. Une évolution de la teneur en polyamines libres a été mise en évidence au cours du développement des embryons zygotiques. Un profil différent en polyamines libres est observé dans les tissus embryogènes et non embryogènes. L'apport d'inhibiteurs de la synthèse de polyamines, DFMO ou CHA, lors de la réinduction diminue l'embryogenèse somatique. L'apport de polyamines semble stimuler la production d'embryons somatiques par explant embryogène.
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Mbongo, Mounoume Aimé. "Synthèse de c-glycosides et application aux dérivés de la n-acetyl-d-glucosamine". Amiens, 1992. http://www.theses.fr/1992AMIES029.
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Dans ce travail, nous avons réalisé la synthèse de c-glycosides en utilisant deux voies de synthèse. La première voie est l'étude de la réaction de Wittig-Horner-Emmons-Wadsworth sur la n-acetyl-d-glucosamine et ses dérivés, puis sur le d-maltose. Nous avons obtenu sélectivement les alpha-c-glycosides. La deuxième voie consiste à l'application d'une nouvelle réaction one pot de type Wittig en présence de zinc, de tri-n-butyl phosphine et de bromoacétate de méthyle sur les dérivés de la n-acetyl-d-glucosamine. Nous avons obtenu de manière stéréospécifique les béta-glycosides. Le remplacement du bromoacétate de méthyle par le bromoacétonitrile ou le chlorométhylphenylsulfure nous a permis d'obtenir respectivement, de manière stéréosélective des c-glycosides nitriles et des glycosylsulfures insaturés avec des rendements satisfaisants
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Hiller, Rebecca Marie. "Mathematical modeling of maltose uptake system in E. coli using nanodisc fluorescence quenching data". Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44253.
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Recent data measured in nanodiscs conflicts with the standard theory of maltose transport in the MalE-MalFGK₂ uptake system found in E. coli. Nanodisc fluorescence quenching data suggest an alternate pathway in which unliganded MalE binds the P-open transporter, facilitating maltose acquisition. Nanodisc data also indicate that MalE regulates maltose uptake at high concentrations. We analyzed four mathematical models of the maltose uptake system: the distinct standard and alternate models, and two integrated models. Nanodisc fluorescence quenching data and nonlinear regression analysis were used to fit equilibrium constants and kinetic rates. The flux through each pathway in an integrated model was calculated using asymptotic analysis and fit parameter values. We conclude that it is likely that transport occurs when liganded MalE associates to a P-open conformation of MalFGK₂, rather than binding to the P-closed transporter as suggested by the standard model. The standard pathway was calculated to be negative, i.e. to occur in reverse as a means of regulating maltose uptake at high concentration. This analysis conflicts with the standard model in which liganded MalE binds to a closed transporter and triggers an opening of the transporter proteins which in turn open the liganded MalE. The analysis also found that a relatively small amount of maltose transport may occur through the alternate pathway involving unliganded MalE.
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Chapon, Christine. "De la régulation de l'expression du système maltose chez Escherichia coli et Klebsiella pneumoniae". Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37596607k.
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L'Hote, Hervé. "Etude génétique et enzymatique de la fermentation du maltose dans une levure de brasserie". Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37599184c.
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Lautenschläger, Friedrich Stefan [Verfasser]. "Einfuss von Maltose-modizierten Polyethylenimin-Nanopartikeln auf mesenchymale Stammzellen und Osteoblasten / Friedrich Stefan Lautenschläger". Gießen : Universitätsbibliothek, 2017. http://d-nb.info/1137466065/34.
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Grand, Maxime. "Régulation des opérons Maltose/Maltodextrines et Gentiobiose induits en contexte d'infection chez Enterococcus faecalis". Thesis, Normandie, 2019. http://www.theses.fr/2019NORMC226.
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Les entérocoques sont des bactéries commensales de l'Homme majoritairement rencontrées dans le tractus digestif. En dépit du caractère bénéfique pour leur hôte, ces microorganismes sont retrouvés au deuxième rang des bactéries responsables d'infection nosocomiales en France ces dernières décennies. Diverses études tendent à montrer que le métabolisme énergétique constitue un facteur crucial pour le processus infectieux des microorganismes. Lors de ce travail, nous nous sommes intéressés à l'étude des métabolismes de différents polymères de glucoses chez Enterococcus faecalis : les maltodextrines et le gentiobiose. L'utilisation du maltose et des maltodextrines est, chez cette bactérie, directement coordonnée au niveau transcriptionnel par le répresseur MalR. L'activité de ce régulateur est rapidement modulée par le maltose qui représente l'inducteur du système et par un corépresseur protéique : la protéine P Ser HPr qui, à l'inverse, favorise la répression exercée par MalR. Le métabolisme des maltodextrines complexes, mais pas le métabolisme du maltose, est également réprimé par le régulateur pléiotrope CcpA en coordination avec son cofacteur P Ser HPr en présence de glucose. La répression catabolique de l'opéron genBA, impliqué dans le métabolisme du β glycoside gentiobiose, est aussi assurée par ce régulateur CcpA en présence de glucose. Cet opéron genBA est responsable de l'import du gentiobiose par un PTS ainsi que de son catabolisme grâce à une hydrolase. L'expression de cette structure opéronique nécessite la présence de l'activateur transcriptionnel GenR actif en présence de l'inducteur gentiobiose 6' PEnterococci are commensal bacteria of Humans predominantly encountered in the digestive tract. Despite their beneficial activity for their host, these microorganisms became the second leading bacterial cause of hospital acquired infections in France for last decades. Some studies showed that the central metabolism is a critical factor for microorganisms infection process. In this study, we worked on the characterisation of metabolisms of the different glucose polymers maltodextrins and gentiobiose in Enterococcus faecalis. The maltose and maltodextrins utilization is coordinated in this bacterium transcriptionally by the MalR repressor. The MalR activity is rapidly modulated by the inducer maltose and by the co repressor P Ser HPr which strengthens the MalR DNA binding. The metabolism of long maltodextrins is also repressed by the pleiotropic regulator CcpA in complex with its essential cofactor P Ser HPr in presence of glucose. The Catabolite repression of the operon genBA, involved in metabolism of the β glycoside gentiobiose, is assumed by CcpA in presence of glucose. This operon genBA allows the gentiobiose uptake with a PTS and its catabolism by a hydrolase. The expression of this latter operon requires both the GenR transcriptional activator and the inducer gentiobiose 6' P
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Cerqueira, Vanessa Cassoni 1980. "Produção de frutose a partir de hidrolisado enzimático de amido de mandioca /". Botucatu : [s.n.], 2012. http://hdl.handle.net/11449/101731.
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Orientador: Cláudio CabelloBanca: Fernando Broetto
Banca: Magali Leonel
Banca: Ana Paula Cerino Coutinho
Banca: Mariana Schimidt Rechsteiner
Resumo: Os produtos das hidrólises de amido são glicose, maltose e uma série de oligossacarídeos e polissacarídeos que encontram utilização principalmente na indústria de alimentos. Neste grupo enquadram-se os adoçantes que aditam sabores a produtos que são demandados por consumidores específicos. Atualmente o açúcar mais utilizado no Brasil é a sacarose, produto extraído da cana-de-açúcar, e o mais utilizado mundialmente é a frutose obtida a partir da hidrólise do milho e posterior isomerização da glicose para frutose. A frutose apresenta capacidade edulcorante 30% maior que a sacarose, 2,5 vezes maior que a glicose e 2 vezes mais solúvel que a glicose, com isso, pode ser utilizada em menor quantidade, diminuindo o poder calórico do alimento e viabilizando sua utilização no tratamento da obesidade. Levando em consideração a importância dos adoçantes para o mercado de alimentos, o presente trabalho teve como objetivo realizar estudos sobre o processo de obtenção da frutose a partir de amido de mandioca. Para a execução dos ensaios utilizou-se fontes comerciais de α- amilase e amiloglucosidase, Liquozyme Supra 2.2X e Saczyme 750 AGUg-1, respectivamente, aplicadas em substrato de amido de mandioca em reator agitado com temperatura controlada. Após o processo de hidrólise enzimática, o hidrolisado passou por um processo de purificação utilizando terra diatomácea e carvão ativado em quatro temperaturas (30, 40, 50 e 60°C), com a finalidade de remoção de contaminantes originários da matéria prima, que levam a odor, cor e sabores indesejáveis. Após o tratamento com carvão ativo e terra diatomácea foram realizados ensaios para estabelecer os melhores parâmetros para a realização do processo de isomerização, buscando a conversão de parte da glicose à frutose, utilizando a enzima... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The products of starch hydrolyses are glucose, maltose and a series of oligosaccharides and polysaccharides which have their main utilization in food industry. This group comprises sweeteners that add flavor to products demanded by specific consumers. Currently the most used sugar in Brazil is sucrose, a product extracted from sugarcane, while the most used sugar worldwide is fructose obtained from maize hydrolysis and subsequent glucose isomerization to fructose. The sweetening capacity of fructose is 30% higher than that of sucrose and 2.5-fold higher than that of glucose; in addition, fructose is 2-fold more soluble than glucose and thus can be used in smaller quantities, decreasing the food's caloric potential and making its use viable in obesity treatment. Considering the importance of sweeteners for the food market, the present study aimed to investigate the process of fructose production from cassava starch. The assays were performed by using commercial sources of α-amylase and amyloglucosidase, Liquozyme Supra 2.2X and Saczyme 750 AGUg-1, respectively, applied to cassava starch substrate in an agitated reactor at controlled temperature. Following the process of enzymatic hydrolysis, the hydrolysate underwent a purification process using diatomaceous earth and activated charcoal at four temperatures (30, 40, 50 and 60°C), in order to remove contaminants originated from the raw material, which lead to undesirable smell, color and flavor. After the treatment with activated charcoal and diatomaceous earth, assays were carried out to establish the best parameters for the isomerization process, aiming at the conversion of part of glucose into fructose, using the enzyme isomerase. The process selected for the studies was in a continuous system where the glucose syrup, previously purified, was continuously pumped... (Complete abstract click electronic access below)
Doutor
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Souza, Cristiane Santos de. "Análise molecular e estrutural da proteína ligadora de maltose (MalE) de Xanthomonas axonopodis pv. citri". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/42/42132/tde-23102009-130040/.
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A captação de maltose em bactérias é feita por um sistema transportador do tipo ABC composto por uma proteína ligadora de substrato (MalE), duas proteínas transmembrana e uma ATPase. No presente trabalho descrevemos a clonagem, expressão e análise bioquímica e estrutural da proteína MalE da bactéria fitopatogênica Xanthomonas axonopodis pv citri (Xac) O gene malE de Xac foi clonado em vetor de expressão pET28a, a proteína recombinante foi expressa em Escherichia coli e purificada por cromatografia de afinidade ao níquel. Amostras da proteína solúvel foram analisadas quanto à estrutura secundária, interação com possíveis ligantes, estabilidade frente a diferentes condições físico-químicas. Ensaios de cristalização possibilitaram a obtenção de cristais em diferentes condições, um deles apresentou grupo espacial P6122, mas não foi possível resolver a estrutura. Com base nas estruturas conhecidas de ortólogos de MalE, geramos um modelo estrutural para a proteína de Xac e foram feitas análises quanto à interação com trealose e maltose. Modelos estruturais dos componentes transmembrana (LacF e LacG) e ATPase (UgpC) do sistema transportador de maltose de Xac também foram gerados. Os resultados representam uma contribuição importante para o conhecimento sobre a fisiologia e sistemas de transporte de Xac.Maltose uptake in bacteria is mediated by an ABC transporter comprising a substrate binding protein (MalE), two transmembrane proteins, and one ATPase. In the present study, we describe the cloning, expression and biochemical as well as structural analyses of the MalE protein of the phytopagen Xanthomonas axonopodis pv citri (Xac). The malE gene of Xac was cloned in the pET28a expression vector, the recombinant protein was expressed in Escherichia coli and, subsequently, purified by nickel affinity chromatography. Samples of soluble protein were analyzed regarding secondary structure, interaction with putative ligants and stability under different physico-chemical conditions. Crystallization trials were carried out under different conditions, one particular condition yielded crystal with a P6122space group, but the structure was not solved. Based on known ortholog structures, a structural model for Xac MalE was obtained allowing interaction with modeled threhalose and maltose. Structural models the transmembrane (LacF and LacG) and ATPase (UgpC) components were also obtained. The present results represent an important contribution to the knowledge of the physiology and transporter systems found in Xac.
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Périon, Régis. "Nouvelles voies d'accès à l'acarbose et à des analogues hypoglycémiants - Synthèses et activités inhibitrices". Rennes 1, 2002. http://www.theses.fr/2002REN10121.
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Duplay, Pascale. "Approche genetique de la topologie fonctionnelle de la proteine affine du maltose chez escherichia coli". Paris 7, 1987. http://www.theses.fr/1987PA077001.
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SCHREIBER, VALERIE. "Mecanismes de regulation de l'activite de malt, l'activateur transcriptionnel du regulon maltose chez escherichia coli". Paris 6, 1999. http://www.theses.fr/1999PA066465.
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Chez les enterobacteries, le regulon maltose regroupe un ensemble d'operons dont les genes codent les proteines du systeme de transport et du metabolisme des maltodextrines et, chez klebsiella oxytoca, les proteines impliquees dans la secretion de la pullulanase. L'expression de ces operons est controlee par un activateur transcriptionnel specifique du regulon maltose, la proteine malt et par un regulateur global, la proteine crp. L'activite de malt (102 kda) est regulee, au niveau de la proteine, positivement par l'atp et le maltotriose et negativement par 3 proteines, malk, maly et aes. Dans un premier temps, a l'aide d'approches biochimiques et biophysiques, nous avons caracterise la structure quaternaire de malt en solution en presence de differentes combinaisons d'effecteurs. Ainsi, nous avons montre qu'en absence d'effecteur malt est monomerique ; (ii) qu'en presence de ces effecteurs positifs, l'atp et le maltotriose, la proteine malt oligomerise en solution et (iii) que son oligomerisation est impliquee dans la fixation de malt sur les promoteurs maltose. Nous avons egalement debute une caracterisation structurale des complexes nucleoproteiques formes entre malt et les promoteurs maltose. La seconde thematique de ce memoire porte sur la repression exercee par la proteine maly sur malt. Bien que le role de maly soit connu depuis longtemps grace a des experiences genetiques, nous ignorions tout du mecanisme moleculaire a la base de cet effet represseur. Nous avons montre (i) qu'un tel mecanisme passe par des interactions directes proteine-proteine entre malt et maly et n'implique aucun autre facteur et (ii) que la fixation de maly sur malt entre en competition avec la fixation du maltotriose sur malt, regulant ainsi l'activite transcriptionnelle de cet activateur.
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Striegler, Christin. "Dendritische Glykopolymere und deren Polyelektrolytkomplexe als effiziente Drug-Delivery-Systeme für die verzögerte Wirkstofffreisetzung aus Calciumphosphatzement". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-213733.
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Das multiple Myelom ist eine seltene maligne Knochenerkrankung bei insbesondere älteren Menschen. Dabei vermehren sich im Knochenmark in hohem Maße unkontrolliert entartete Plasmazellen. Diese Myelomzellen unterdrücken einerseits die Bildung von normalen Plasmazellen, andererseits wird das Gleichgewicht zwischen Knochenaufbau und –abbau empfindlich gestört, woraus eine erhöhte Knochenresorption resultiert. Neben den bisher angewandten Chemo- und Strahlentherapien gewinnen innovative Medikamente, wie Proteasominhibitoren und Bisphosphonate, in der Therapie an Bedeutung. Diese Medikamente reduzieren das Myelomzellwachstum und wirken hemmend auf den Knochenabbau.
Durch das Auffüllen von durch Resorptionsprozesse geschädigten Knochendefekten mit wirkstoffbeladenen Calciumphosphatzementen (CPC) wird nicht nur der Knochen stabilisiert, sondern im Vergleich zur herkömmlichen oralen oder intravenösen Medikamentenverabreichung eine gezielte Freisetzung des Wirkstoffes direkt am Wirkort in wesentlich reduzierten Dosen ermöglicht. Durch die Kombination des Knochenzementes mit anderen effizienten Drug-Delivery-Systemen (DDS), wie z. B. Polymeren, kann eine optimale Anpassung der Wirkstofffreisetzung ermöglicht werden. Insbesondere haben sich bereits dendritische Polymere aufgrund ihrer globularen Struktur und Vielzahl an peripheren Funktionalitäten als besonders geeignete Wirkstoffträgersysteme herausgestellt. Bei der Anwendung im physiologischen System spielt insbesondere die Biokompatibilität dieser polymeren DDS eine entscheidende Rolle. Durch Modifizierung der peripheren Gruppen mit biokompatiblen Einheiten, wie Oligosacchariden oder Aminosäuren, kann die physiologische Verträglichkeit signifikant erhöht werden.
Für die Behandlung des multiplen Myeloms am Knochen sollte in dieser Arbeit ein geeignetes dendritisches DDS auf Basis von hochverzweigtem Polyethylenimin (PEI) synthetisiert und charakterisiert werden. Das DDS sollte dabei verschiedene Anforderungen, wie eine hohe Wasserlöslichkeit und Biokompatibilität, erfüllen. Weiterhin sollten die mechanischen Eigenschaften des CPC nicht negativ beeinflusst werden und der Wirkstoff sollte effektiv vom DDS aufgenommen und kontrolliert aus dem generierten Komposit (Wirkstoff/DDS/CPC) freigesetzt werden.
In der sogenannten N-Carboxyanhydrid (NCA)-Polymerisation wurden am PEI(5) (5 ≙ Mw 5 kDa) benzylgeschützte Polyglutaminsäure bzw. Polyasparaginsäureketten aufgepfropft. Durch hydrolytische Abspaltung der Schutzgruppen an den PBLG-Ketten von PEI(5)-PBLG-346 und PEI(5)-PBLA-346 erfolgte die Generierung der wasserlöslichen DDS PEI(5)-PGlu-346 und PEI(5)-PAsp-346. Die Charakterisierung der synthetisierten Kern-Schale-Architekturen PEI(5)-PBLG-346, PEI(5)-PBLA-346, PEI(5)-PGlu-346 und PEI(5)-PAsp-346 zeigte, dass nur wenige lange Polyaminosäureketten an wenigen primären und sekundären Aminogruppen des PEI(5) aufgebaut wurden. Aufgrund der noch freien primären und sekundären Aminogruppen am PEI(5) und den peripheren Aminogruppen an den Polyaminosäureketten wurden durch die Anbindung von Maltose- bzw. Laktoseeinheiten Kern-Schale-Architekturen mit einer binären Doppelschalenstrukturen erzeugt. Im Gegensatz zu reiner Polyglutaminsäure zeigten die mit Glutaminsäure modifizierten Polymerstrukturen PEI(5)-PGlu-346 und PEI(5)-PGlu-346-Mal interessante strukturelle Eigenschaften in wässriger Umgebung. Aufgrund des pH-abhängigen Ladungszustandes resultiert bei reinen Polyglutaminsäureketten normalerweise der typische Helix-Coil-Übergang. Dabei findet eine Konformationsumwandlung der α-helikalen Struktur zur ungeordneten Sekundärstruktur statt. Im Falle der PEI(5)-PGlu-346- und PEI(5) PGlu-346-Mal-Copolymere wurde jedoch keine α-helikale Konformation bei niedrigem pH-Wert nachgewiesen. Die PGlu-Ketten der wasserlöslichen Kern-Schale-Architekturen bildeten sowohl im sauren, als auch im basischen pH-Wertbereich eine ungeordnete Sekundärstruktur aus. Zusätzlich konnte nachgewiesen werden, dass die Kern-Schale-Architekturen in Abhängigkeit vom pH-Wert als isolierte Makromoleküle bzw. Aggregate mit unterschiedlich lang gestreckten Peptidketten vorliegen. Die Ursache dafür sind nicht-kovalente, intra- und intermolekular wirkende Kräfte.
Zur Beurteilung der Kern-Schale-Architekturen als geeignete DDS wurde die Komplexierung des Proteasominhibitors Bortezomib (BZM) in die reinen Copolymere PEI(5)-PGlu-346, PEI(5)-PGlu-346-Mal und PEI(25)-Mal B (25 ≙ Mw 25 kDa, ohne Polyglutaminsäureketten) sowie deren Polyelektrolytkomplexe untersucht. Dabei wurden Copolymer/BZM- bzw. PEK/BZM-Komplexe in verschiedenen Verhältnissen hergestellt und die Komplexierungskapazität durch zeitabhängige Ultrafiltration UV/Vis-spektroskopisch ermittelt. Im Vergleich zu den glutaminsäuremodifizierten Copolymeren wurde durch PEI(25)-Mal B etwa doppelt so viel Wirkstoff in verschiedenen wässrigen Systemen aufgenommen. Der Grund dafür ist der größere PEI-Kern und die dementsprechend höhere Anzahl an peripheren Aminogruppen mit gebundenen Maltoseeinheiten. Die PEK zeigten im Vergleich zu den Copolymeren keine Verbesserung der Komplexierungskapazität.
Um eine effektive Wirkstofffreisetzung für eine dosierte Langzeittherapie aus dem Kompositmaterial zu erhalten, ist eine stark verzögerte Freisetzung des Copolymers bzw. PEK selbst aus dem CPC notwendig. In Abhängigkeit von der Konzentration wurde für PEI(25)-Mal B eine geringere Freisetzung aus dem Copolymer/CPC- und PEK/CPC ermittelt. Aufgrund der nanoskaligen Dimension der polymeren Strukturen wird die Diffusion durch das offene CPC-Porensystem erschwert. Für die PEI(5)-PGlu-346, PEI(5)-PGlu-346-Mal und die zugehörigen PEK wurde hingegen keine messbare Freisetzung aus dem CPC nachgewiesen. Die Glutaminsäureeinheiten können Calciumionen komplexieren und beeinflussen dadurch die Keimbildung und das Wachstum der CaP-Phase. Die Copolymerstrukturen werden somit in den CPC integriert und können nur durch Abbau des schwerlöslichen Zementes freigesetzt werden.
Bei den Untersuchungen der BZM-Freisetzung aus den BZM/Copolymer/CPC- und BZM/PEK/CPC-Kompositen kristallisierte sich BZM/PEI(5)-PGlu-346-Mal/CPC als effektivstes DDS heraus. Im Vergleich zum reinen BZM in CPC wurde nach 24 h nur etwa die Hälfte des Wirkstoffes aus dem Komposit freigesetzt. Weiterhin steigerte sich die Freisetzungsrate über den gesamten Zeitraum von 14 Tagen auf nur etwa 60 %. Aus dem BZM/CPC-Komposit wurden nach 14 Tagen mehr als 75 % BZM freigesetzt.
In Kooperation mit der Arbeitsgruppe von Prof. Michael Gelinsky vom Zentrum für Translationale Knochen-, Gelenk- und Weichgewebeforschung (TU Dresden) wurde keine signifikante Änderung der Druckfestigkeit des CPC durch die Integration der glutaminsäuremodifizierten Copolymere festgestellt. Weiterhin wurde in in vitro-Untersuchungen mit osteogen stimulierten humanen mesenchymalen Stammzellen (hMSC) kein entscheidender Einfluss der in dieser Arbeit hergestellten PEI(5)-PGlu-346- und PEI(5)-PGlu-346-Mal-Copolymere auf die Proliferation der Zellen beobachtet. Zudem war bei beiden Copolymeren eine osteogene Differenzierung der hMSC zu knochenbildenden Osteoblasten nachweisbar, wobei PEI(5)-PGlu-346-Mal die Entwicklung der Stammzellen zu knochenbildenden Zellen sogar zu fördern scheint.
Durch die Kombination von hochverzweigtem PEI mit Polyglutaminsäure und Maltose wurde in dieser Arbeit ein innovatives DDS für die kontrollierte und effektiv verzögerte Freisetzung von BZM aus CPC erzeugt, welches die einleitend erwähnten Anforderungen erfüllt. Das Copolymersystem weist eine hohe Biokompatibilität auf, ohne die mechanischen Eigenschaften des CPC zu verändern. Diese Arbeit hat daher einen entscheidenden Beitrag im Bereich der Wirkstofffreisetzung aus festen Materialien geliefert und bildet die Grundlage für zukünftige polymere DDS in CPC.
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Santos, Tiago Tedeschi dos. "Influência da inoculação de ingredientes intra ovo em aspectos produtivos e morfológicos de frangos de corte oriundos de distintos pesos de ovos". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-25042007-090912/.
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O presente trabalho teve o objetivo de verificar a influência da inoculação de ingredientes intra ovo aos 18 dias de incubação de ovos oriundos de matrizes jovens e de pesos distintos. Ovos oriundos de matrizes com 30 semanas de idade foram separados em ovos leves e pesados, sendo incubados na mesma máquina incubadora. Aos 18 dias de incubação, no momento da transferência para o nascedouro, os ovos foram inoculados com soluções de Maltose, Polivitamínico, Zinco-Glicina, Glutamina, Mistura de todos os produtos descritos anteriormente e Cloreto de Sódio (controle). Como via de inoculação, as soluções foram utilizadas como diluentes da vacina de Marek efetuada intra-ovo aos 18 dias de incubação. Após o nascimento, 2460 pintinhos machos foram enviados para o aviário experimental onde foram divididos em 60 boxes em um delineamento inteiramente casualizado em esquema fatorial 2x6 (2 pesos e 6 soluções) totalizando 12 tratamentos com 5 repetições de 40 aves. Foram sacrificadas uma ave por repetição aos 00, 07 e 21 dias de idade para pesagem do saco da gema, intestino e fígado. Amostras de duodeno, jejuno e íleo foram enviadas para histologia para determinação de profundidade de criptas e altura de vilosidades. Amostras de sangue foram coletadas e enviadas para laboratório para determinação de nível de anticorpos contra reovírus e bronquite aviária. Os animais e a ração fornecida foram pesados semanalmente (07, 14, 21, 28, 35 e 42 dias) para determinação do peso, consumo e conversão alimentar. Aos 43 dias de idade 3 aves por repetição foram pesadas e sacrificadas para determinação do peso e rendimento de carcaça, peito com osso e pele e perna com osso e pele. Animais oriundos de ovos mais pesados obtiveram uma maior eclosão, peso ao nascimento e peso de fígado e intestino aos 00 dias. O peso aos 42 dias foi superior em aves oriundas de ovos pesados, produzindo uma carcaça e peito mais pesado, porém sem diferença de rendimento. Não houve diferença de conversão aos 42 dias de idade. Viabilidade de animais oriundos de ovos pesados foi superior de 00 a 07, 14 a 21 e 21 a 28 dias de idade, mas não afetou a viabilidade final. Peso do ovo não interferiu com o nível de anticorpos. As inoculações de soluções aos 18 dias de incubação obtiveram resultados variáveis dependendo do produto utilizado, tendo maior influência sobre altura de vilosidades e profundidade de criptas e sobre a produção de anticorpos. Não afetaram, entretanto, os parâmetros zootécnicos (ganho de peso, consumo de ração, conversão alimentar e viabilidade). A inoculação de produtos intra-ovo já é uma técnica possível de ser utilizada na avicultura industrial, entretanto, novos estudos devem ser ainda desenvolvidos no intuito de definir o melhor produto ou composto de produtos a ser utilizadoThis trial had the objective to verify the influence of the in-ovo inoculation of ingredients at 18th day of incubation of eggs from different weights. Eggs from a broiler breeder flock with 30 weeks of age were separated in light and heavy eggs and were incubated in the same machine. At the 18th day of incubation, when the eggs were been transferred, they were inoculated with solutions of Maltose, Vitamins, Zinc-Glicine, Glutamine, mixture of all the ingredients and sodium chloride (control). The solutions were inoculated as Marek\'s vaccine diluter. After the eclosion, 2460 male chicks were send to the experimental house were they were divided on 60 boxes at a completely random design and a factorial 2x6 (two egg weigths and six solutions) design, summing 12 treatments with 5 repetitions of 40 chicks. One chick per repetition was sacrificed at 00, 07 and 21 days of age to weigth the yolk sac, intestine and liver. Samples of duodenum, jejunum and ileum were sent to histology to determinate villus high and cripts deep. Blood sample of the same birds were collected and sent to the laboratory to determinate anti body levels against reovirus and avian bronquitis. Animals and feed were weighted every week to determine the animal weight gain, feed consumption and feed conversion. At 43 days of age, 3 birds per repetition were weighted and sacrificed to determinate the carcass, breast and leg weight and yield. Animals from heavy eggs had a higher born weight, eclosion and liver and intestine weight at 00 days. At 42 days of age, birds from heavier eggs had a higher weight producing a heavier carcass and breast, but without yield variation. There was no difference on feed conversion at 42 days. Liveability of birds from heavier eggs were higher form 00 to 07, 14 to 21 and 21 to 28 days of age, but it didn\'t interfere the total livibility. Egg weight didn\'t interfere on the anti body level. The solutions inoculated at 18th day of incubation had variable results depending on the product utilized, influencing the villus height and cripts deep and anti body production. However, the solutions inoculation doesn\'t interfere on zoothecnical parameters as weight gain, feed consumption, feed conversion and livability. The in-ovo inoculation is a technique possible to be used on broiler production, however, new studies have to be done searching from the best product or ingredient to be used
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Oliveira, Camila Fernanda Dias de. "Produção de pigmentos por Monascus ruber CCT 3802 a partir do xarope de maltose como substrato". Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/7711.
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Artificial dyes are commonly used in the food industry, both for their low cost and for ease of procurement. The consumer market, however, requires healthier products and a viable alternative would be the use of natural pigments. In addition to plants, flowers, fruits and animals, micro-organisms can be the source of this type of pigment, such as fungi, bacteria and microalgae. Therefore, the present study had as objective to produce pigments from the solid fermentation and submerged by filamentous fungus Monascus ruber CCT 3802 using maltose syrup as substrate. The effect of substrate concentration on maltose syrup and the influence of pH on pigment production was studied by evaluating the radial growth rate, pigment production and pigment properties by thermal stability. The main results demonstrate that the highest radial growth velocity was obtained from the plate containing 5 g L-1 maltose syrup 0.1053 mm h-1 , which corresponds to an increase of 71.70% when compared to the medium extract of Malt agar (MEA). In the submerged fermentation the concentration of 10 g L-1 of maltose obtained the highest absorbance (14.54 AU), lower biomass (4.65 g L-1 ) and greater dark red intensity. For pH determination, the highest radial growth rate was obtained when the fungus was cultivated at pH 6.5 and the production of yellow pigment was obtained at low pH (2.0 and 2.5) while the production of orange pigments was in the pH range (3.0 and 3.5) and the red pigment yield obtained when the fungus was grown at pH above 4.0. Thus, it can be concluded that maltose syrup and pH exerted a significant influence on both the radial growth rate and the production of pigments in submerged fermentation, showing that lower substrate concentrations favor higher amounts of red pigment and that associated with the culture in PH 6.5 favored the formation of red pigments.
Corantes artificiais são comumente utilizados na indústria de alimentos, tanto pelo seu baixo custo quanto pela facilidade de obtenção. O mercado consumidor, entretanto, requer produtos mais saudáveis e uma alternativa seria a utilização de pigmentos naturais. Além de plantas, flores, frutos e animais, micro-organismos podem ser fonte deste tipo de pigmento, como fungos, bactérias e microalgas. Portanto, o presente estudo teve como objetivo produzir pigmentos a partir da fermentação sólida e submersa pelo fungo filamentoso Monascus ruber CCT 3802 utilizando xarope de maltose como substrato. Foi estudado o efeito da concentração do substrato xarope de maltose e a influência do pH na produção de pigmentos, avaliando a velocidade de crescimento radial, a produção de pigmentos e as propriedades dos pigmentos mediante a estabilidade térmica. Os principais resultados demonstram que a maior velocidade de crescimento radial foi obtida da placa contendo 5 g L-1 de xarope de maltose 0,1053 mm h-1 , que corresponde ao um aumento de 71,70% quando comparado com o meio extrato de malte ágar (MEA). Na fermentação submersa a concentração de 10 g L-1 de maltose obteve a maior absorbância (14,54 UA), menor biomassa (4,65 g L-1 ) e maior intensidade da cor vermelho escuro. Já para determinação da influência do pH a velocidade de crescimento radial mais elevada foi obtida quando o fungo foi cultivado em pH 6,5. A obtenção dos pigmentos, amarelo, laranja e vermelho, deu-se nos intervalos de pH 2,0-2,5, 3,0-3,5 e acima de 4,0 respectivamente. Assim, pode-se concluir que a concentração de xarope de maltose e o pH exerceram influência significativa tanto na velocidade de crescimento radial quanto na produção de pigmentos em fermentação submersa, mostrando que menores concentrações de substrato favorecem maiores quantidades de pigmento vermelho e que associados ao cultivo em pH 6,5 favoreceram a formação de pigmentos vermelhos.