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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.
111

Bactérias com potencial probiótico isoladas do intestino de camarão marinho Litopenaeus vannamei (Boone, 1931)

VIDAL, Juliana Maria Aderaldo 27 July 2015 (has links)
Submitted by (edna.saturno@ufrpe.br) on 2017-02-23T14:03:29Z No. of bitstreams: 1 Juliana Maria Aderaldo Vidal.pdf: 784041 bytes, checksum: f927beb63f5c3c304d4098214b0dd629 (MD5) / Made available in DSpace on 2017-02-23T14:03:29Z (GMT). No. of bitstreams: 1 Juliana Maria Aderaldo Vidal.pdf: 784041 bytes, checksum: f927beb63f5c3c304d4098214b0dd629 (MD5) Previous issue date: 2015-07-27 / Bacteria with probiotic effect have been used in marine shrimp production like antibiotics substitution, contributing to the health of the host, by antagonistic action to pathogenic micro-organisms or by competition for space and nutrients, and improving appetite and lead the further growth of the animals. When isolated from the host itself is safe to use, being able to adhere and colonize the intestine. The objective was to isolate probiotic bacteria from intestine of juvenile Litopenaeus vannamei and evaluate the effects of probiotic administration in the performance of cultivated animals experimental challenged infection. Intestinal bacteria were from cultivated shrimp in oligohaline water and saltwalter in dry and rainy seasons, and confronted with Vibrio parahaemolyticus, Vibrio vulnificus, Vibrio alginolyticus and Aeromonas hydrophila. Bacteria showed antimicrobial effect have been identified by molecular biology. Twenty-nine isolates showed antagonistic effect at least one of the tested pathogens. The species that most occurred was Bacillus cereus, the producing of the largest zones of inhibition to the V. alginolyticus and V. vulnificus. The bacterium Citrobacter freundii, from oligohaline water showed the best antimicrobial effect before the four pathogens. The probiotic Bacillus cereus was tested in diet for marine shrimp post-larvae against challenge with V. parahaemolyticus, and V. alginolyticus which evaluated the growth performance of animals, colonization capacity of the probiotic bacteria, pathogens count and histopathological lesions. The use of probiotic had no effect on animals survival, but not for treatments which was used probiotic had a lower weight gain. Animals fed dietary supplementation of probiotic had lower pathogens count those fed without the use. Histopathological lesions were observed in organs and tissues of animals. It can be concluded that it was possible to isolate bacteria having probiotic effect of marine shrimp intestine, wherein the strain Bacillus cereus demonstrated high capacity to colonize the host itself, causing a significant reduction of pathogens. / Bactérias com efeito probiótico contribuem para saúde de camarões marinhos em cultivo, em substituição aos antibióticos, exercendo ação antagonista à micro-organismos patogênicos ou por competição por espaço e nutrientes, além de melhorar o apetite levando a um maior crescimento dos animais. Quando isolados do próprio camarão seu uso é seguro, por serem capazes de aderir ou colonizar o intestino destes. Neste sentido, objetivou-se isolar bactérias probióticas do intestino de juvenis de Litopenaeus vannamei e avaliar os efeitos da sua administração sobre o desempenho dos animais cultivados frente infecção experimental. Foram isoladas bactérias do intestino de camarão cultivado em águas oligohalina e salgada, em períodos seco e chuvoso, e confrontadas com Vibrio parahaemolyticus, Vibrio vulnificus, Vibrio alginolyticus e Aeromonas hydrophila, em testes in vitro. As bactérias que produziram efeito antimicrobiano foram identificadas através de biologia molecular.Vinte e nove isolados apresentaram efeito antagônico a pelo menos um dos patógenos testados. A espécie que mais ocorreu foi Bacillus cereus, produzindo os maiores halos de inibição frente ao V. alginolyticus e V. vulnificus. A bactéria Citrobacter freundii, proveniente de água oligohalina apresentou melhor efeito antimicrobiano, perante os quatro patógenos. O probiótico Bacillus cereus foi testado em ração para pós-larvas de L. vannamei, frente a desafio com V. parahaemolyticus, e V. alginolyticus quando avaliou-se o desempenho zootécnico dos animais, a capacidade de colonização das bactérias probióticas, contagem de patógenos e lesões histopatológicas. O uso do probiótico não influenciou nas taxas de sobrevivência dos animais, porém nos tratamentos em que não se utilizou probiótico houve menor ganho de peso. Os animais que receberam ração suplementada de probiótico, tiveram contagem de patógenos inferior aqueles alimentados sem o uso. Não foram observadas lesões histopatológicas nos órgãos e tecidos dos animais. Concluiu-se que é possível isolar bactérias com efeito probiótico do intestino do camarão marinho, sendo que a cepa de Bacillus cereus demonstrou maior capacidade de colonizar o próprio hospedeiro, diminuindo os patógenos.
112

Electric DNA chips for determination of pathogenic microorganisms

Liu, Yanling January 2008 (has links)
Silicon-based electric DNA chip arrays were utilized to fast identify pathogenic microorganisms with respect to the capacity to produce toxins involved in foodborne poisoning and infections. Bacteria of the B. cereus and the enterohemorrhagic E. coli (EHEC) groups contain different set-ups of various virulence factors that are encoded by the corresponding genes. The purpose of this work was to develop a fast and simple method for determination of the presence of these virulence genes in a colony from primary enrichment cultures. A target gene is detected through hybridization to a surface-immobilized specific capture probe and biotin-labeled detection probe. Following binding of an enzyme conjugate to this sandwich hybrid complex, a current signal is generated by electronic redox recycling of the enzymatic product paminophenol (pAP). Two versions of the assay were developed. In the first version the capture probes were immobilized on magnetic beads, which carried out all reactions until the pAP generation, while the final electric signal was created by transferring pAP to a single-electrode chip surface. In the second version a silicon chip array with 16 parallel sensing electrode positions each of them functionalized by capture probes, carried out all assay steps on the chip surface. This instrument can realize automatic and multiplexed gene detection. The kinetics of bacterial cell disruption and impact of DNA fragmentation by ultrasound were determined. The experimental data suggested that the increased signal after first minutes of ultrasonication were due to the accumulation of released DNA amount, while the further signal increase resulted from the improved hybridization with the shortened target DNA strands. Studies on probe localization on the 16-electrode chip assays indicated that the probe-targeting site, which was located at the 5’-end of strands, gave rise to the highest signal level due to the efficient targetprobes hybridization and the following enzyme binding. When these functionalized chip arrays were exposed to the cell homogenates, the sensing electrodes were fouled by cellular proteins and therefore led to dramatically decreased redox-recycling current. To circumvent this, samples were treated by DNA extraction after the 1st sonication and then DNA fragmentation by a 2nd time sonication. The DNA extract removed most of the interfering components from bacterial cell. This sample treatment was applied to characterize one “diarrheal” and one “emetic” strain of B. cereus with the chip arrays functionalized by eight DNA probes. The signal patterns of eight virulence genes from chip assays agreed well with PCR control analyses for both strains. By simply adding the SDS detergent to cell homogenates, chip surface blocking effect can be significantly reduced even without DNA extraction treatment. After optimization of some critical factors, the 16-electrode DNA chips with the improved sensing performance can directly detect multiple virulence genes from a single E. coli colony in 25 min after the introduction of supernatant of ultrasonicated cell lysate. / QC 20100824
113

Electric DNA arrays for determination of pathogenic Bacillus cereus

Liu, Yanling January 2007 (has links)
<p>Silicon-based electric chip arrays were developed for characterization of Bacillus</p><p>cereus with respect to the capacity to produce toxins involved in food poisoning and foodborne infections. Bacteria of the B. cereus group contain different sets of four toxins encoded by eight genes. The purpose of this work was to develop a fast method for determination of the presence of these genes in colonies from primary enrichment cultures. The specific DNA detection was based on immobilization of DNA capture probes, which hybridize to specific sites on the target genes. Biotin-labeled detection probes were designed to hybridize with the target DNA adjacent to the capture probes. An extravidin - alkaline phosphatase complex was subsequently bound to the hybridized detection probes. Finally, p-aminophenyl phosphate was added as substrate for the enzyme, and the product p-aminophenol was brought in contact with the interdigitated gold electrode on the silicon chips surface. The p-aminophenol was oxidized at the anode to quinoneimine, which was then reduced back to paminophenol at the cathode. This redox recycling generates a current that was used as the DNA-chip response to the target DNA. Two versions of the assay were used. In the first version the capture probes were immobilized on magnetic beads and all</p><p>chemical reactions until and including the enzymatic reaction took place in an</p><p>eppendorf tube while the redox recycling was used to measure the amount of paminophenol produced after transfer from the tube to the silicon chip surface. In the second version a silicon chip array was used with 16 parallel electrode positions, each activated by immobilization of one type of capture probes on the gold electrodes. With this system all chemical reactions took place at the chip surface. The kinetics of cell disruption and DNA fragmentation from B. cereus by ultrasonication was determined. Maximum cell disruption was achieved within 5 min and the chip response increased in proportion to the ultrasonic time. Further ultrasonication up to 10 min resulted in further increasing current although no further cell disruption was observed. If the sonication time was extended above 10 min the signal declined. Based on analysis of the DNA size distribution by early end-point PCR and gel electrophoresis, it is suggested that the first 5 min ultrasonication increased the signal by increasing the release of target DNA molecules. Thereafter the signal was increased by fragmentation of target DNA which increases the diffusion rate and also the accessibility of the hybridization site. Finally, the DNA fragment sizes approached that of the hybridization site (51-bp) which may reduce the signal because of cleavage of the target DNA in the hybridization region. These studies were performed with the bead-based hybridization assay. The assay was highly specific to the target gene (hblC) of both B. cereus and B. thuringiensis with no response from negative control</p><p>cells of B. subtilis. The 16 positions of the silicon chip array were activated by</p><p>immobilization of all known toxin-coding genes of B. cereus and also included both a positive control and a negative control electrode positions. When these chips were exposed to ultrasonicated B. cereus, the gold electrodes were fouled by some component in DNA cell lysates. To circumvent this, the released large DNA was first extracted and then ultrasonicated again, since the extract mainly contains large molecular weight DNA. This DNA extract was applied to characterize one “diarrheal” and one “emetic” strain of B. cereus with the DNA chip arrays. The results agreed with PCR control analysis which means that these electric DNA chip arrays can be used to characterize bacterial colonies with respect to the genes coding of all known toxins of B. cereus: haemolysin (hblA, hblC, hblD), non-haemolytic enterotoxin (nheA, nheB, nheC), cytotoxin K-2 (cytK-2), and cereulide (ces). The chip assay required about 30 min after application of DNA samples. Due to the generic properties of the chips, this technique should also be applicable for characterization of the pathogenicity potential of many other organisms. Keywords: Bacillus cereus, haemolysin, non-haemolytic enterotoxin, cytotoxin K-2, cereulide, toxin-coding genes, bacterial colony, electric DNA chip, ultrasonication, DNA fragmentation.</p>
114

Etude structurale d'un switch moléculaire impliqué dans le quorum sensing chez Bacillus cereus

Zouhir, Samira 14 September 2012 (has links) (PDF)
Les bactéries utilisent un mode de communication appelé quorum sensing pour régulerl'expression des gènes en fonction de la densité de population et contrôler ainsi de façonmulticellulaire des processus tels que la sporulation, la compétence ou la virulence. Chez les bactériesà Gram-positif, le quorum sensing repose principalement sur la production, la sécrétion et la détectionde petits peptides de signalisation.Le projet porte sur l'étude du système quorum sensing: NprR/NprX chez Bacillus cereus, oùNprR est l'effecteur qui reconnait spécifiquement le peptide de signalisation NprX. NprR est uneprotéine bi-fonctionnelle. Seule, elle agit en tant qu'inhibiteur de la sporulation, en complexe avecNprX, elle perd sa fonction initiale au profit d'une activité facteur de transcription impliquée dans lavirulence. NprR appartient à une famille d'effecteurs de quorum sensing appelée RNPP (Rap, NprR,PlcR et PrgX) encore mal caractérisée au niveau structural. Mon projet de thèse a consisté en l'analysestructure-fonction du système NprR/NprX.Pour comprendre la régulation fonctionnelle de NprR par NprX, des études en solution (SECMALSet DLS) ont permis de mettre en évidence un switch moléculaire qui repose sur un changementd'oligomérisation. Ainsi NprX fait basculer NprR d'une conformation Apo dimérique à uneconformation compléxée tétramérique.L'étude structurale par cristallographie a aboutit à la résolution de la structure du complexeNprR/NprX. L'analyse de ce tétramère suggère la reconnaissance de 2 sites distincts sur l'ADN.L'étude structurale par SAXS, a quant à elle, permis de proposer une conformation dimérique de laforme Apo NprR, modèle conforté grâce à une étude par mutagénèse dirigée des résidus d'interface. Ils'agit d'un mode de dimérisation semblable à celui des protéines Rap (membres de la famille RNPP).La caractérisation par ITC de l'interaction NprR/NprX avec différentes formes du peptide,ainsi que l'analyse de la poche de fixation du complexe, ont permis de mieux comprendre la spécificitéd'interaction et de mettre en évidence deux résidus clés de l'effecteur : l'Asn275 essentielle à lafixation du peptide et l'Arg 126 essentielle à l'activation de la fonction facteur de transcription.Ces travaux ont contribué à une meilleure compréhension du système quorum sensingNprR/NprX grâce à l'élucidation du switch moléculaire contrôlé par NprX mais aussi à une meilleureconnaissance de la famille d'effecteurs RNPP.
115

Etude du système de communication cellulaire NprR-NprX au sein du groupe Bacillus cereus

Dubois, Thomas 05 March 2012 (has links) (PDF)
Chez les bactéries sporulantes du genre Bacillus, des mécanismes importants tels que la sporulation et la virulence sont régulés par des systèmes de communication cellulaire qui impliquent des peptides de signalisation et des régulateurs de la famille RNPP (Rap, NprR, PlcR, PrgX). L'objectif de mon travail de thèse a été de déterminer le rôle du régulateur NprR chez les bactéries du groupe B. cereus. Ce travail se divise en trois parties complémentaires. La première partie a consisté à montrer que NprR est impliqué dans un système de communication cellulaire. Nous avons montré que NprR est un régulateur transcriptionnel de début de phase stationnaire qui est dépendant du peptide de signalisation NprX. Associé à NprX, NprR active la transcription du gène nprA qui code pour une protéase extracellulaire. Nous avons démontré que le peptide NprX est sécrété, maturé puis réimporté dans la cellule bactérienne par deux systèmes d'oligopeptide perméase (Opp et Npp). Une fois dans la cellule, la forme mature de NprX (vraisemblablement l'heptapeptide SKPDIVG) se lie à NprR et permet la transcription du gène nprA. Nous avons ensuite cherché à déterminer la fonction de ce régulateur au cours du cycle infectieux de B. thuringiensis (Bt) chez l'insecte. Nous avons montré que NprR est actif après la mort de l'insecte et permet aux bactéries de survivre, sous forme de cellules végétatives, dans les cadavres. Une analyse transcriptomique indique que NprR régule l'expression d'au moins 41 gènes qui codent notamment pour des enzymes dégradatives et un locus de gènes impliqués dans la production d'un peptide synthétisé de façon non ribosomique (la kurstakine). Nous avons démontré que les gènes codant pour les enzymes dégradatives s'expriment spécifiquement après la mort de l'hôte et que les produits de ces gènes sont essentiels pour hydrolyser différents substrats (protéines, lipides, chitine), ce qui suggère que Bt a un mode de vie nécrotrophe dans le cadavre. La kurstakine est essentielle pour la survie de Bt pendant son développement nécrotrophe et nous avons montré que cette molécule est nécessaire pour le swarming et la formation de biofilm. Par ailleurs, un mutant du gène nprR ne se développe pas et ne sporule pas efficacement dans le cadavre. L'ensemble de nos résultats indiquent que le necrotrophisme est un mode de vie hautement régulé, qui est essentiel dans le cycle infectieux de Bt car il contribue à la transmission horizontale de ce micro-organisme. Enfin, nous avons étudié la régulation de l'expression des gènes nprR et nprX. Nous avons montré que les gènes nprR-nprX sont co-transcrits à partir d'un promoteur dépendant de sigma-A (PA) situé en amont du gène nprR. La transcription à partir de ce promoteur débute lors de l'entrée en phase stationnaire et est contrôlée par deux régulateurs transcriptionnels: CodY et PlcR. Le répresseur CodY pourrait se lier à l'ADN en amont du promoteur PA et réprimer la transcription des gènes nprR-nprX pendant la phase exponentielle de croissance. Au début de la phase stationnaire, le contrôle négatif de CodY est levé et PlcR active la transcription de nprR-nprX en se liant à une boîte PlcR située en amont de PA. Nos résultats indiquent que nprX est également transcrit indépendamment de nprR à partir de deux promoteurs, PH et PE, respectivement dépendant de sigma-H et sigma-E. Les deux promoteurs permettent d'assurer la transcription de nprX en phase stationnaire tardive alors que la transcription à partir du promoteur PA est achevée. Cette étude met en évidence le role clé des régulateurs CodY, PlcR and Spo0A dans la régulation de l'expression des gènes nprR-nprX.
116

Mécanismes d'adaptation aux basses températures de croissance de la bactérie pathogène B. cereus : rôle des hélicases à ARN

Pandiani, Franck 16 December 2010 (has links) (PDF)
Bacillus cereus est une bactérie largement disséminée dans la nature, contaminant ainsi les aliments en contact avec le sol. En France, cette bactérie est considérée comme le quatrième agent de toxi infection alimentaire collective. Pour être pathogène, B. cereus doit être capable de se multiplier lors des différentes étapes de transformation et notamment au cours de la réfrigération. Le but de cette étude a été d'étudier les mécanismes moléculaires de la réponse adaptative au froid et en particulier le rôle des hélicases à ARN de B. cereus ATCC 14579. Le gène cshA, codant pour une hélicase à ARN putative, a été identifié par une approche de mutagénèse aléatoire, comme jouant un important dans l'adaptation au froid de B. cereus. La souche ATCC 14579 possède 5 gènes codant pour des hélicases à ARN, cshA à cshE qui sont tous fortement surexprimés à 10°C par rapport à 37°C et quel que soit le stade de croissance considéré. La délétion simple des gènes cshA, cshB et cshC conduit à l'apparition de phénotypes cryosensibles, se traduisant par une incapacité d'adaptation au froid par rapport à la souche sauvage, associée à une modification de la morphologie cellulaire. De plus, CshA, CshB et CshC possèdent chacune un domaine de température où leur action est prépondérante. Elles semblent également être impliquées dans l'adaptation au stress oxydant et au stress basique, alors que CshD et E n'ont pas de rôle dans l'adaptation aux stress testés. Nous avons montré que CshA est indispensable à basse température, pour permettre le maintien de la stabilité des ribosomes avec lesquels elle interagit directement, mais aussi pour réguler la dégradation des ARNr. L'identification des partenaires protéiques interagissant avec CshA suggérent qu'elle puisse être également impliquée dans un complexe de dégradation des ARN.
117

Probiótico, prebiótico e simbiótico na nutrição de juvenis de carpa capim

Geraldo, Andressa Mariza Ribeiro 21 July 2016 (has links)
Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2017-06-05T17:38:31Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) ANDRESSA MARIZA RIBEIRO GERALDO.pdf: 730207 bytes, checksum: 5df837babcc118e5f1db740d596c32b6 (MD5) / Approved for entry into archive by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2017-06-05T17:42:09Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) ANDRESSA MARIZA RIBEIRO GERALDO.pdf: 730207 bytes, checksum: 5df837babcc118e5f1db740d596c32b6 (MD5) / Made available in DSpace on 2017-06-05T17:42:09Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) ANDRESSA MARIZA RIBEIRO GERALDO.pdf: 730207 bytes, checksum: 5df837babcc118e5f1db740d596c32b6 (MD5) Previous issue date: 2016-07-21 / O objetivo deste estudo foi avaliar o desempenho de carpas capim (Ctenopharyngodon idella) alimentadas com dietas suplementadas com diferentes aditivos no consumo de forragem teosinto (Euchlaena mexicana). O delineamento foi inteiramente casualizado com 4 tratamentos em triplicata, sendo, TCont: dieta controle; TPre: dieta com prebiótico (casca de soja: 5%/Kg de ração); TPro: dieta com probiótico (B. cereus e B. subtilis: 0,5%/Kg de ração) e TSim: dieta com simbiótico (níveis de probiótico e prebiótico juntos). As rações formuladas tinham 30% PB e 3000 kcal/ED/Kg. O período experimental foi de 70 dias nos quais os peixes foram alimentados com 3% PV de ração e forragem ofertada a vontade. Foram avaliados os parâmetros de desempenho zootécnico, conversão alimentar aparente, índices corpóreos, análise centesimal corporal e parâmetros hematológicos. Para análise estatística foi realizada ANOVA com P<0,05 e teste de comparação de médias. Os resultados indicaram que a inclusão de probiótico, prebiótico e simbiótico na concentração usada apresentaram melhor consumo de forragem em relação ao controle, mas não em relação o desempenho zootécnico dos animais. Também, a inclusão dos aditivos proporcionou menor gordura corporal nos animais. Palavras chave: Aquicultura. Bacillus cereus. Bacillus subtilis. Casca de soja. Ctenopharyngodon idella. Nutrição de peixes. / The aim of this study was to evaluate the performance of grass carp (Ctenopharyngodon idella) fed diets supplemented with different additives in the consumption of forage teosinte (Euchlaena mexicana). The experimental design was completely randomized with 4 treatments in triplicate being TCont: control diet; Tpre: prebiotic (soybean hulls: 5%/kg of diet); TPro: Probiotic (B. cereus and B. subtilis: 0.5%/kg of diet) and Tsyn: synbiotic (probiotic and prebiotic levels together). The diets formulated had 30% CP and 3000 kcal / DE / kg. The experimental period was 70 days in which fish were fed 3% BW feed and forage offered ad libitum. It were evaluated the growth performance parameters, aparent feed conversion, corporeal indices, chemical analysis of the boby and hematological parameters. Statistical analysis was performed with ANOVA P <0.05 and mean comparison test. The results may indicate that the addition of probiotic, prebiotic and synbiotic in the concentration used showed better forage intake compared to control, but not over the growth performance of animals. Also, the inclusion of additives provided lower body fat in animals.
118

Produção e avaliação microbiológica, fíco-química e toxicológica de farinha de pilosocereus chrysostele e sua utilização como aditivo na formulação de broa preta. / Production and microbiological, physicochemical and toxicological evaluation of meal of pilosocereus chrysostele and its use as an additive in the formulation of black bread.

DEODATO, José Nildo Vieira. 15 May 2018 (has links)
Submitted by Élida Maeli Fernandes Quirino (maely_sax@hotmail.com) on 2018-05-15T17:53:27Z No. of bitstreams: 1 JOSÉ NILDO VIEIRA DEODATO - DISSERTAÇÃO PPGSA PROFISSIONAL 2015..pdf: 1086003 bytes, checksum: 950808ed6f7e78ee6247df21a718613b (MD5) / Made available in DSpace on 2018-05-15T17:53:27Z (GMT). No. of bitstreams: 1 JOSÉ NILDO VIEIRA DEODATO - DISSERTAÇÃO PPGSA PROFISSIONAL 2015..pdf: 1086003 bytes, checksum: 950808ed6f7e78ee6247df21a718613b (MD5) Previous issue date: 2015-03-20 / As cactáceas constituem um importante elemento da paisagem, apresentando caules suculentos, cobertos por espinhos de diversas formas, tamanhos e dimensões, junto a outras espécies de cactáceas, formam a paisagem típica da região semiárida do Brasil. O facheiro é uma cactácea xerófila, robusta, pouco ramificada, de cor verde-escura, armada de espinhos agudos; com flores grandes isoladas e altas. A proposta do trabalho foi obter farinhas da casca e da polpa do facheiro e determinar as características microbiológica, físico-químicas e toxicológicas, a fim de utilizar no desenvolvimento de produtos da panificação, aceitáveis pelos consumidores. Foram preparadas quatro formulações (5, 10, 15 e 20%), variando-se a quantidade adicionada à formulação básica das broas. Utilizou-se o Teste de aceitação com escala hedônica estruturada de nove pontos, incluindo questões sobre consumo e compra do produto. Os resultados das análises microbiológicas atenderam aos padrões exigidos pela legislação vigente, apresentando resultados negativos para coliforme a 45° C, Staphylococcus aureus, Bacillus cereus, bactérias aeróbios mesófilos, bolores e leveduras e Salmonella sp. Nos resultados físicoquímicos obtidos a partir da casca e polpa do facheiro, apresentaram baixos valores de umidade e elevado teor de cinzas, fibras alimentares e lipídeos e quantidades razoáveis de proteínas. Nenhum efeito tóxico foi observado. A farinha de facheiro como substituição a farinha tradicional produziram broas pretas sensorialmente aceitáveis em relação à aceitabilidade global e intenção de compra dos provadores. Comprovando a eficácia na produção da farinha, e a qualidade higiênica sanitária das mesmas, podendo ser utilizada em formulações de inúmeros alimentos, sem comprometer a qualidade de seus produtos junto a saúde do consumidor. / The cacti are an important element of the landscape, with succulent stems, covered with spines of many shapes, sizes and dimensions, where it grows in rocky soils and, along with other cactus species, form the typical landscape of the semi-arid region of Brazil. The facheiro (Pilosocereus chrysostele) is a xerophytic cactus, rugged, sparsely branched, dark green color, armed with sharp thorns; with large isolated and tall flowers. he purpose of this study was to develop a study to obtain flour from the stems and bark facheiro in four different temperatures and determine the microbiological characteristics, physicochemical and toxicological in order to investigate the potential use in the food industry and check for the possibility of developing new products of baking, acceptable by consumers. Four formulations (5, 10, 15 and 20%), by varying the amount added to the basic formulation of the cookie, in order to support product development in the field of baking, the bread black production process. We used the acceptance test with hedonic scale of nine points, including questions about consumption and purchase. The results of the microbiological analyzes in the four flours met the standards required by law, with negative results for coliform 45 ° C, Staphylococcus aureus, Bacillus cereus, aerobic mesophilic bacteria, molds, yeasts and Salmonella sp. In physical-chemical results obtained from the pulp and peel facheiro showed lower values of moisture and high ash content, fiber and lipids and reasonable amounts of protein. No toxic effects were observed, indicating the safety of this product for supplementation in food. Facheiro flour as a replacement to traditional flour produced black bagel sensorial quality in the overall acceptability and purchase intent of tasters. Proving the efficiency in the production of flour, and sanitary hygienic quality of the same and can be used in many food formulations without compromising the quality of their products to consumers' health. Keywords: Facheiro wheat product development.
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Electric DNA arrays for determination of pathogenic Bacillus cereus

Liu, Yanling January 2007 (has links)
Silicon-based electric chip arrays were developed for characterization of Bacillus cereus with respect to the capacity to produce toxins involved in food poisoning and foodborne infections. Bacteria of the B. cereus group contain different sets of four toxins encoded by eight genes. The purpose of this work was to develop a fast method for determination of the presence of these genes in colonies from primary enrichment cultures. The specific DNA detection was based on immobilization of DNA capture probes, which hybridize to specific sites on the target genes. Biotin-labeled detection probes were designed to hybridize with the target DNA adjacent to the capture probes. An extravidin - alkaline phosphatase complex was subsequently bound to the hybridized detection probes. Finally, p-aminophenyl phosphate was added as substrate for the enzyme, and the product p-aminophenol was brought in contact with the interdigitated gold electrode on the silicon chips surface. The p-aminophenol was oxidized at the anode to quinoneimine, which was then reduced back to paminophenol at the cathode. This redox recycling generates a current that was used as the DNA-chip response to the target DNA. Two versions of the assay were used. In the first version the capture probes were immobilized on magnetic beads and all chemical reactions until and including the enzymatic reaction took place in an eppendorf tube while the redox recycling was used to measure the amount of paminophenol produced after transfer from the tube to the silicon chip surface. In the second version a silicon chip array was used with 16 parallel electrode positions, each activated by immobilization of one type of capture probes on the gold electrodes. With this system all chemical reactions took place at the chip surface. The kinetics of cell disruption and DNA fragmentation from B. cereus by ultrasonication was determined. Maximum cell disruption was achieved within 5 min and the chip response increased in proportion to the ultrasonic time. Further ultrasonication up to 10 min resulted in further increasing current although no further cell disruption was observed. If the sonication time was extended above 10 min the signal declined. Based on analysis of the DNA size distribution by early end-point PCR and gel electrophoresis, it is suggested that the first 5 min ultrasonication increased the signal by increasing the release of target DNA molecules. Thereafter the signal was increased by fragmentation of target DNA which increases the diffusion rate and also the accessibility of the hybridization site. Finally, the DNA fragment sizes approached that of the hybridization site (51-bp) which may reduce the signal because of cleavage of the target DNA in the hybridization region. These studies were performed with the bead-based hybridization assay. The assay was highly specific to the target gene (hblC) of both B. cereus and B. thuringiensis with no response from negative control cells of B. subtilis. The 16 positions of the silicon chip array were activated by immobilization of all known toxin-coding genes of B. cereus and also included both a positive control and a negative control electrode positions. When these chips were exposed to ultrasonicated B. cereus, the gold electrodes were fouled by some component in DNA cell lysates. To circumvent this, the released large DNA was first extracted and then ultrasonicated again, since the extract mainly contains large molecular weight DNA. This DNA extract was applied to characterize one “diarrheal” and one “emetic” strain of B. cereus with the DNA chip arrays. The results agreed with PCR control analysis which means that these electric DNA chip arrays can be used to characterize bacterial colonies with respect to the genes coding of all known toxins of B. cereus: haemolysin (hblA, hblC, hblD), non-haemolytic enterotoxin (nheA, nheB, nheC), cytotoxin K-2 (cytK-2), and cereulide (ces). The chip assay required about 30 min after application of DNA samples. Due to the generic properties of the chips, this technique should also be applicable for characterization of the pathogenicity potential of many other organisms. Keywords: Bacillus cereus, haemolysin, non-haemolytic enterotoxin, cytotoxin K-2, cereulide, toxin-coding genes, bacterial colony, electric DNA chip, ultrasonication, DNA fragmentation. / QC 20101111
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Avaliação de indutores de resistência biótico, abiótico e extratos vegetais no controle de Meloidogyne incognita em tomateiro / Evaluation of resistance inductors biotic, abiotic and plant extracts for the control of Meloidogyne incognita on tomato plants

Formentini, Heloísa Maria 31 August 2012 (has links)
Made available in DSpace on 2017-07-10T17:40:42Z (GMT). No. of bitstreams: 1 Heloisa_Maria_Formentini_tese.pdf: 1264963 bytes, checksum: d416be804a86c6ba7273d6aacedf8878 (MD5) Previous issue date: 2012-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In Brazil, the tomato is one of the vegetable species of great importance both economically and socially, however several factors are limiting its production as an example the diseases caused by nematodes of the genus Meloidogyne that limit the production in infested areas. Seeking new measures of protection and control of plant disease induced resistance is na alternative considerering that little attention has been directed to the possibility of induced resistance to root pathogens like nematodes. Therefore, this study aimed to verify the effectiveness of the chemical inducer acibenzolar-S-methyl, the biotic inductor Bacillus cereus and plant extracts of rosemary (Rosmarinus officinalis) and turmeric (Curcuma longa) in the induced resistance in susceptible and resistant tomato in plants infected with Meloidogyne incognita race 3. Two experiments were conducted simultaneously both followed the 2 x 6 factorial design with two tomato genotypes, one susceptible to M. incognita (Santa Clara) and a resistant (Ivety) and six treatments: ASM (125 mg i.a L -1 ), Bacillus cereus (6.10 7 CFU mL -1 ), rosemary 10%, turmeric 10%, water and a control (no inoculum and no spraying in the aerial part), with five replicates. Each vase with a capacity of 2 L, were filled with a mixture of soil, sand and compost previously autoclaved and homogenized in the ratio 2:2:1 and were transplanted to each one three tomato seedlings susceptible and resistant. The treatments were sprayed in the aerial part in tomato plants in all vases except the absolute control. At 72 h after the first application of treatments was carried out the inoculation of 407/100 cm 3 of J2 and eggs per vase. In the first experiment, using destructive samples of tomato treated and inoculated with M. incognita were determined the response of both genotypes to the treatments applied to the enzymatic activity of peroxidase, polyphenol oxidase, chitinase, β-1,3 glucanase and phenylalanine ammonia-lyase from roots of tomato plants that were macerated and homogenized to withdrawals in time 0 h, 24 h, 48 h, 96 h and 120 h after the first application of the treatments. In the second experiment, the variables analyzed to determine the effect of treatments on nematode population were the number of root-knots, juveniles and eggs in the soil accomplished at 56 days after the first application of the treatments that were reapplied every seven days during this period. From the results obtained it was concluded that there was a reduction in the number of root-knots in the roots of tomato plants showing no difference between the two genotypes for plants that received the treatments with acibenzolar-S-methyl, turmeric, rosemary and B. cereus. There was a reduction in the formation of root-knots in susceptible cultivar, confirming their potential in protecting the genotypes used against the attack of M. incognita. For the enzimatic activity peroxidase was the enzyme strongly associated with resistance with the highest activity in resistant genotype if compared to susceptible regardless of inducer treatment. In susceptible tomato B. cereus stood out in the induction of chitinase and peroxidase whereas for the resistant tomato rosemary induced peroxidase and polyphenol oxidase and rosemary extracts and turmeric induced chitinase enzyme to the susceptible genotype / No Brasil o tomate é uma das espécies de hortaliças de grande importância tanto no ponto de vista econômico quanto social, no entanto vários fatores são limitantes para sua produção como exemplo as doenças causadas por fitonematoides principalmente as espécies do gênero Meloidogyne que inviabilizam a produção nas áreas infestadas. Buscando novas medidas de proteção e controle de doenças de plantas a indução de resistência é uma alternativa haja vista que pouca atenção tem sido direcionada a possibilidade de indução de resistência à patógenos do sistema radicular como os fitonematoides. Assim este trabalho teve como objetivo verificar a eficácia do indutor químico acibenzolar-S-metil, do indutor biótico Bacillus cereus e de extratos vegetais de alecrim (Rosmarinus officinalis) e cúrcuma (Curcuma longa) na indução de resistência em tomateiros suscetível e resistente infectados com Meloidogyne incógnita raça 3. Foram conduzidos dois experimentos simultaneamente ambos seguiram o esquema fatorial 2 x 6 com dois genótipos de tomateiro um suscetível à M. incognita (Santa Clara) e um resistente (Ivety) e seis tratamentos: ASM (125 mg i.a L -1 ), Bacillus cereus (6.10 7 UFC mL -1 ), alecrim 10%, cúrcuma 10%, água e uma testemunha absoluta (sem inóculo e sem pulverização na parte aérea), com cinco repetições. Cada vaso, com capacidade para 2 L, foram preenchidos com a mistura de solo, areia e composto orgânico previamente autoclavados e homogeneizados na proporção 2:2:1 e para cada vaso foram transplantados três mudas de tomateiro suscetível e resistente. Os tratamentos foram pulverizados na parte aérea dos tomateiros em todos os vasos com exceção da testemunha absoluta. Às 72 h após a primeira aplicação dos tratamentos foi realizada a inoculação de 407/100 cm 3 de J2 e ovos por vaso. No primeiro experimento, utilizando amostras destrutivas de tomateiros tratados e inoculados com M. incognita foram determinadas a resposta dos dois genótipos aos tratamentos aplicados para a atividade enzimática das enzimas peroxidase, polifenoloxidase, quitinase, β-1,3 glucanase e fenilalanina amônia-liase a partir do macerado homogeneizado das raízes dos tomateiros para o tempo de coleta 0 h, 24 h, 48 h, 96 h e 120 h após a aplicação dos tratamentos. No segundo experimento, as variáveis analisadas para determinar o efeito dos tratamentos sobre a população do nematoide foram o número de galhas, juvenis e ovos presentes no solo realizado aos 56 dias após a primeira aplicação dos tratamentos que foram reaplicados a cada sete dias durante este período. A partir dos resultados obtidos concluiu-se que houve uma redução no número de galhas no sistema radicular dos tomateiros não apresentando diferença entre os dois genótipos para as plantas que receberam os tratamentos com acibenzolar-S-metil, cúrcuma, alecrim e Bacillus cereus. Houve uma redução na formação de galhas na cultivar suscetível, confirmando seu potencial na proteção dos genótipos utilizados contra o ataque do M. incognita. Para a atividade enzimática a peroxidase foi a enzima que esteve fortemente associada à resistência com a atividade superior no genótipo resistente em relação ao suscetível independentemente do tratamento indutor. No tomateiro suscetível o B. cereus destacou-se na indução de peroxidase e quitinase enquanto que para o tomateiro resistente o alecrim induziu peroxidase e polifenoloxidase e os extratos de alecrim e cúrcuma induziram a enzima quitinase para o genótipo suscetível

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