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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Produção, purificação e estudos das caracteristicas bioquimicas de glicosiltransferase de Erwinia sp. D-12 : produção de isomaltulose a partir de sacarose

Celestino, Erica Marcondes 02 December 1998 (has links)
Orientador: Helia Harumi Sato / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-24T10:49:42Z (GMT). No. of bitstreams: 1 Celestino_EricaMarcondes_M.pdf: 11335011 bytes, checksum: 3f2ff33ca438910d6a2f4f959aaad1df (MD5) Previous issue date: 1998 / Resumo: Trezentas e quatorze linhagens de microrganismos foram isoladas de amostras de mel, flores, frutas, caldo, melaço e mosto de usina de álcool e açúcar e testadas quanto a capacidade de produção de glicosiltransferase, que catalisa a conversão de sacarose em isomaltulose (6-O-8-Dglicopirano sil-D-frutofuranose). A isomaltulose também conhecida como palatinose apresenta baixo potencial cariogênico e tem sido utilizada na produção de balas, gomas de mascar e produtos de confeitaria. A linhagem D-12 produtora de glicosiltransferase foi selecionada e identificada como Erwinia sp. pelas características morfológicas e bioquímicas. Estudou-se a produção, purificação e a caracterização bioquÚ1lica da glicosiltransferase intracelular da linhagem de Erwinia sp. D-12. No estudo da produção de glicosiltransferase de Erwinia sp. D-12, em meio de cultura composto de 6% de sacarose, 6% de peptona e 0,4% de extrato de carne, em fermentador de 2L verificou-se que a enzima é produzida na fase exponencial de crescimento, sendo que a produção máxima foi obtida após 3 horas de fermentação a 28°C e, após 4 horas de incubação a 30°C e 35°C. A enzima foi purificada através da cromatografia em colunas de DEAE-Sephadex A-50 e DEAE-Sepharose CL-6B. A glicosiltransferase purificada apresentou atividade ótima em pH 6,0 e a 40ºC. A glicosiltransferase purificada de Erwinia sp. D-12 é termo sensível sendo inativada após 1 hora de tratamento a temperaturas superiores a 39°C e após 3 horas a 35°C na ausência de substrato. A enzima mostrou-se estável na faixa de pH 5,7 a 6,3 após 24 horas de incubação a 5°C. Os valores de Km e Vmáx da enzima purificada foram respectivamente, 138mM de sacarose e 9,81 µmol de isomaltulose/minuto/mg de proteína. A atividade de glicosiltransferase não foi afetada por KCL MgS04, CaCh, NaCI, Na2HAsO4 na concentração 10mM, em relação ao volume final da mistura de reação, enquanto que os sais de CoCh, ZnCh, FeCh e CUSO4 não afetaram sua atividade nas concentrações de O,lmM e 1,0mM. Os sais MnCl2 e Pb(CH3COO)2 na concentração de 0,1mM não inibiram a atividade de glicosiltransferase. A atividade residual de glicosiltransferase na presença de MnCl2, nas concentrações 1mM e 10mM, foi respectivamente 93,0% e 73,7% enquanto que na presença de Pb(CH3COO)2, nestas concentrações, a atividade residual foi 98,3% e 93,3%. O sal BaCl2 não inibiu a atividade da glicosiltransferase na concentração de 0,1mM. O sal AgNO3 inibiu cerca de 37% a atividade de glicosiltransferase na concentração de 0,1mM e inibiu completamente na concentração 1,0mM enquanto que o HgCl2 inibiu completamente a enzima na concentração 1mM em relação ao volume final de reação. Os reagentes ácido etilenodiaminotetracético e L-cisteína nas concentrações 0,1mM, 1,0mM e 10mM em relação ao volume final da mistura de reação não inibiram a atividade de glicosiltransferase. A atividade de glicosiltransferase não foi inibida pelos reagentes azida de sódio e dietilditiocarbamato de sódio nas concentrações 0,1mM e 1,0mM. O reagente p-cloromercuribenzoato inibiu a atividade de glicosiltransferase nas concentrações 0,1mM e 1,0mM e a atividade residual na presença do inibidor foram respectivamente 79,8% e 60,7%. O reagente N-bromosuccinimida inibiu cerca de 6% a atividade de glicosiltransferase na concentração 0,1mM e inibiu completamente a enzima na concentração 1,0mM. A iodoacetamida inibiu a atividade de glicosiltransferase na concentração final 1,0mM e 10,0mM e a atividade na presença do inibidor foram respectivamente 65,5% e 21,3%. O peso molecular da glicosiltransferase purificada da linhagem Erwinia sp. D- 12 foi estimado em 63.000 daltons através da filtração em gel Sephadex G -200. No estudo da aplicação da glicosiltransferase de Erwinia sp. D-12 na conversão de sacarose em isomaltulose utilizando-se solução 5% e 10% de sacarose foram obtidos rendimento de 73,5% e 72,3% de isomaltulose respectivamente, após 4 horas de reação a 40°C / Abstract: Three hundred and fourteen strains of microorganisms were isolated from honey, flowers, fruit, sugar cane juice, sugar cane molasses and must samples obtained from alcohol and sugar producing plants and examined for their capacity to produce glycosyltransferase, which converts sucrose to isomaltulose (6-0-a-D-glucopyranosll-D-fructofuranose). Isomaltulose, also known as palatinose, has low cariogenic activity and has been used in the production of candies, chewing gums and confectionary products. The glucosiltransferase producing strain was selected and identified as Erwinia sp. according to its morphological and biochemical characteristics. The production, purification and biochemical characterization of intracellular glucosyltransferase from the strain Erwinia sp. D-12 was studied. The production of glucosyltransferase was performed in a 2L jar fermentor using the following medium: 6% sucrose, 6% peptone and 0.4% meat extract. It was shown that the enzyme was produced during the exponential growth phase and maximum activity was verified after three hours of fermentation at 28°C or after 4 hours fermentation at 30°C or 35°C. The enzyme was purified by DEAE-Sephadex A-50 and DEAE-Sepharose CL-6B column chromatography. The purified glucosyltransferase showed optimum activity at pH 6.0 and 40°C. The purified glucosyltransferase is thermosensitive and was inactivated after one hour of treatment at temperatures above 39°C or after 3 hours at 35°C in the absence of substrate. The enzyme was stable between pH 5.7 and pH 6.3 after 24 hours incubation at 5°C. The kinetic parameters Km and Vmax with respect to sucrose were 138mM and 9.81µmol of isomaltulose/minute/mg protein respectively. The glycosyltransferase activity was not affected by KCI, MgSO4, CaCl2, NaCl, NaHAsO4 at concentrations of 10mM with respect to the [mal volume ofthe reaction mixture while the salts CoCh, ZnCl2, FeCl2 and CUS04 did not affect its activity at concentrations of O.lmM and 10mM: The salts MnCh and Pb(CH3COO)2 did not inhibit glucosyltransferase activity at a concentration of 0.1mM. The residual activity of glucosyltransferase in the presence of 1mM and 10mM MnCl2 was respectively 93.0 and 73.7%, whereas in the presence of Pb(CH3COO)2 at the same concentrations it was 98.3 and 93.3%. The salt BaCl2 did not inhibit glucosyltransferase activity at a concentration of 0,1mM. The salt AgNO3 inhibited about 37% of the glucosyltransferase activity at a concentration of 0.1 mM and completely inhibited it at a concentration of 1.0mM. The salt HgCl2 completely inhibited the enzyme activity at a concentration of 1mM with respect to the final volume of the reaction mixture. Ethylenediaminetetraacetic acid and L-cystein at concentrations of 0.1, 1.0 and 10mM with the respect to the final volume of the reaction mixture did not inhibit glucosyltransferase activity. The enzyme was not inhibited by sodium azide or sodium diethyldithyocarbamate at concentrations of 0.1 and 1.0mM. The p-chloromercuribenzoate reagent at concentrations of 0.1mM and 1.0mM inhibited glucosyltransferase activity, resulting in residual activity of 79.8 and 60.7% respectively. The N-bromosuccinimide reagent inhibited about 6% of the glucosyltransferase activity at a concentration of 0.lmM and completely inhibited it at a concentration of 1.0mM. Iodoacetamide inhibited glucosyltransferase activity at concentrations of 1.0 and 10.0 mM, resulting in residual activity of 65.5 and 21.3% respectively. The molecular weight of purified glucosyltransferase was determined as being 63.000 daltons by Sephadex G-200 gel filtration. The application of glucosyltransferase from Envinia sp. D-12 in the conversion of sucrose to isomaltulose was studied using 5 and 10% sucrose solutions, giving yields of 73.5 and 72.3% after 4 hours of reaction at 40°C / Mestrado / Mestre em Ciência de Alimentos
2

The regulation of virulence in Pectobacterium atrosepticum

Cubitt, Marion Faye January 2014 (has links)
No description available.
3

Differences in soft rot Erwinia spp. in pathogenicity to corn and sensitivity to an inhibitory fraction from corn

Hartman, John Richard, January 1971 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1971. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.
4

Ecology of Erwinia carotovora and factors affecting tuber susceptibility to bacterial soft rot

De Boer, Solke Harmen, January 1976 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1976. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 97-108.
5

Native extrachromosomal deoxyribonucleic acid in Erwinia carotovora var. carotovora.

Daughtrey, Margery Louise 01 January 1978 (has links) (PDF)
No description available.
6

Isolation and partial characterization of the intercellular pectic enzyme complex from Erwinia carotovora isolate 14.

Stack, James Peter 01 January 1978 (has links) (PDF)
No description available.
7

Production of extracellular pectic enzymes from Erwinia carotovora (Isolate 14) incubated under aerobic and anaerobic conditions.

Novak, Stephen John 01 January 1981 (has links) (PDF)
No description available.
8

Characterization of a bacterial chitinase.

Weir, Mary Pickett 01 January 1978 (has links) (PDF)
No description available.
9

Characterisation of c-di-GMP metabolism, virulence and motility in Erwinia carotovora subsp. atroseptica

Tan, Hui January 2012 (has links)
No description available.
10

The isolation and identification of soft rot Erwinia from Saguaro (Carnegiea gigantea) flowers

Schuyler, Mary Esther, 1943- January 1968 (has links)
No description available.

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