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1
Васильєва, К. О., e І. М. Волошина. "Біотехнологічні аспекти Bifidobacterium". Thesis, Київський національний університет технологій та дизайну, 2020. https://er.knutd.edu.ua/handle/123456789/15599.
Testo completo
2
Bahaka, Driss. "Analyse phenotypique et genotypique des souches du genre bifidobacterium appartenant ou apparentees aux especes b. Breve, b. Infantis et b. Longum". Lille 2, 1993. http://www.theses.fr/1993LIL2P254.
Testo completo
3
Grill, Jean-Pierre. "Étude du potentiel probiotique de bactéries du genre Bifidobacterium : purification et caractérisation de la fructose 6 phosphate phosphocetolase de Bifidobacterium longum et Bifidobacterium animalis". Nancy 1, 1995. http://www.theses.fr/1995NAN10050.
Testo completoAbstract (sommario):
Cette étude a permis de montrer les effets de certaines souches de bactéries appartenant au genre Bifidobacterium sur la flore intestinale, les nitrites, les nitrosamines et les sels biliaires. L’enzyme impliquée dans la déconjugaison des sels biliaires a été purifiée et caractérisée pour la souche de Bifidobacterium longum BB536. La fructose 6 phosphate phosphocétolase a été purifiée et caractérisée chez différentes souches de bifidobactéries. Des séquences en acides aminés de cette protéine ont ainsi été obtenues pour Bifidobacterium longum et Bifidobacterium animalis
4
Oberg, Taylor S. "Characterization of the Hydrogen Peroxide Stress Responses of Bifidobacterium longum and Bifidobacterium animalis subsp. Lactis". DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/2037.
Testo completoAbstract (sommario):
Probiotics are living organisms which exert a beneficial health effect when consumed in sufficient numbers. Consumer interest in probiotics has increased dramatically in recent years prompting an increase in production and development of functional foods. One major problem is the decreased viability of probiotic bacteria during functional food production and storage and subsequent digestion due to environmental stresses. The most common probiotic strains belong to the genus Lactobacillus or Bifidobacterium. Due to the anaerobic nature of these bacteria, they lack the required defense mechanisms for oxidative stress inherent in aerobic microorganisms. This study examined the oxidative stress responses of six strains of Bifidobacterium, which are commonly used as probiotics in functional foods.The first phase of the study investigated the innate and inducible hydrogen peroxide (H2O2) stress response of Bifidobacterium longum strains NCC2705 and D2957, Bifidobacterium longum ssp. infantis ATCC 15697, and Bifidobacterium animalis ssp. lactis strains BL-04, DSM10140 and RH-1. Strains were screened for survival at increasing concentrations of H2O2 and lethal and sublethal concentrations were determined for each. In the second phase, B. animalis ssp. lactis strains BL-04 and DSM10140 and B. longum strains NCC2705 and D2957 were treated with a sublethal H2O2 concentration and RNA samples were collected for transcriptome analysis after 5 min and either 20 or 60 min. Statistical analysis was performed to identify genes that increased or decreased in expression during H2O2 treatment compared to control cells.Results showed that survival was species and strain dependent and that strains which naturally survived higher H2O2 concentrations had a larger number of differentially expressed genes early on during H2O2 exposure. Some of the protective genetic systems that were activated during H2O2 stress are mechanisms which perform basic cellular functions under normal conditions such as deoxuynucleotide synthesis. Under stress conditions, these systems can be used to detoxify oxidative free radicals. Also a number of genes involved in sugar transport and energy production for the cell showed increased expression, which reveals the increased energy needs of the cells during oxidative stress.During testing, it was found that two B. animalis ssp. lactis strains, BL-04 and DSM10140, had differing levels of survival and gene expression during H2O2 exposure despite having almost identical genome sequences. It was determined that one possible cause of the differences was a genetic deletion in a gene that allows the cell to incorporate extracellular fatty acids into the cell membrane instead of synthesizing them.Results from this project have increased the understanding of oxidative stress responses in bifidobacteria and highlighted possible methods to increase bacterial survival during food manufacture, storage, and human digestion.
5
Nunoura, Naoki. "Studies on Bifidobacterium breve β-Glucosidase". Kyoto University, 1997. http://hdl.handle.net/2433/202382.
Testo completoAbstract (sommario):
Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第6899号
農博第917号
新制||農||739(附属図書館)
学位論文||H9||N3023(農学部図書室)
16016
UT51-97-H283
京都大学大学院農学研究科食品工学専攻
(主査)教授 熊谷 英彦, 教授 木村 光, 教授 清水 昌
学位規則第4条第1項該当
6
Hassi, Chafiq. "Contribution a l'etude d'utilisation de la n-acetyl-beta-d-glucosamine par b. Bifidum atcc 15696 et b. Animalis atcc 25527 : preparation, purification et caracterisation de leur n-acetyl-beta-d-glucosaminidase". Lille 2, 1994. http://www.theses.fr/1994LIL2P253.
Testo completo
7
Mizerovská, Lucie. "Selektivní izolace bakterií rodu Bifidobacterium z potravin". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2012. http://www.nusl.cz/ntk/nusl-216880.
Testo completoAbstract (sommario):
Probiotic lactic acid bacteria (LAB) are very often used in food procesing industry, such as milk products, cheese and fermentsd salami production in nova days. In diploma thesis were tested symbiotic food supplements from different producers. Bacterial DNA was isolated from crude cell lysates of six food suplements by magnetic particles P(HEMA-co-GMA). PCR-ready DNAs were isolated. from all products The detection of Bifidobacterium bacteria identified by PCR was in agreement with those declared by the manufacturers. Magnetic particles with immobilized antibodies against Bifidobacterium were used in the next part of thesis. These particles were used for the isolation of target cells from two products with cell identification by genus specific PCR.
8
Orrhage, Kerstin. "Impact of Bifidobacterium longum and Lactobacillus acidophilus on the intestinal microflora and bioavailability of some food mutagens /". Stockholm, 1999. http://diss.kib.ki.se/1999/91-628-3687-0/.
Testo completo
9
Appourchaux, Laurence. "Purification et propriétés des béta-D-galactosidases des N-acétyl-béta-D-glucosaminidases de Bifidobacterieum bifidum souche AA 2/2". Lille 1, 1989. http://www.theses.fr/1989LIL10164.
Testo completoAbstract (sommario):
Quatre activités exoglycosidasiques de bifidobacterium bifidum souche AA/22 ont été étudiées. Il s'agit des activités: béta-galactosidase, n-acétyl-beta-hexosaminidase, alpha-neuraminidase et alpha-fucosidase. Ces activités sont endo-cellulaires, leur extraction est réalisée par ultra-sons. Le schéma de purification suivi nous a permis d'obtenir six fractions. Trois fractions ne contenant qu'une seule activité : une alpha-neuraminidase et deux beta-galactosidases. Trois fractions possèdent chacune deux activités : une béta-galactosidase et une alpha-fucosidase ; une alpha-neuraminidase et une n-acétyl-béta-hexosaminidase ; une béta-galactosidase et une n-acétyl-béta-hexosaminidase. Toutes ces fractions ne révèlent qu'une seule bande en électrophorèse non dénaturante. Nous avons vérifié que celles-ci correspondaient bien aux activités suivies. Les deux activités béta-galactosidase purifiées séparément sont homogènes en électrophorèse dénaturante. Toutes ces activités ont des températures optimales comprises entre 40 et 48°C. Les pH optimaux sont compris entre 5 et 6. 5 et les masses moléculaires relatives déterminées en gel filtration sur Superose 6 varient de 97000 à 420000. Les pHi sont acides (4 a 5. 1). Seule une activité béta-galactosidase est sensible à l'EDTA et à l'EGTA, de plus Elle est activée par le calcium et le magnésium. Les paramètres enzymatiques des béta-galactosidases ont été réalisés sur le pNP-Gal et sur le lactose, ils mettent en évidence trois groupes de réactivité différente. Tous ces paramètres nous permettent de conclure que Bifido bacterium bifidum souche AA/22 possède au moins trois béta-galactosidases différentes. Nous n'avons pas prouvé que dans les fractions contenant deux activités, nous étions en présence d'un complexe enzymatique. Mais nous avons montré que la présence d'une activité influençait la réactivité de l'autre activité présente.
10
Boutry, Etienne. "Exoglycosidases de Bifidobacterium bifidum souche AA 2/2". Lille 1, 1989. http://www.theses.fr/1989LIL10163.
Testo completoAbstract (sommario):
La production de beta-d-galactosidase (EC. 3. 2. 1. 23), de n-acetyl-beta-d-glucosaminidase (EC. 3. 2. 1. 30), de neuraminidase (EC. 3. 2. 1. 18) et d'alpha-l-fucosidase (EC. 3. 2. 1. 51) a été optimisée par fermentation. La bactérie anaérobie Bifidobacterium bifidum souche AA/22 a été cultivée en milieu liquide renfermant par litre : 37 g d'un extrait sec de cerveau-cœur, 10 g de glucose et des facteurs bifidigènes (1 g de gynolactose ou 66 ml de lait de femme). La fermentation est conduite sous N2/CO2 à 37°C et à ph 6,8. L'extraction des systèmes enzymatiques par une technique aux ultra-sons a été optimisée en tampon phosphate de sodium 20 mm ph 6,8 renfermant de l'EDTA 20 mm et 0,1 p. 100 de nonidet P 40. Après centrifugation d'une heure à 100 000 g la solution enzymatique obtenue renferme: 7 U de beta-d-galactosidase, 1,6 U de n-acetyl-beta-d-glucosaminidase, 90 mU de neuraminidase et 400 mU de fucosidase par mg de protéine. Une neuraminidase a été purifiée jusqu'à homogénéité en électrophorèse dénaturante (SDS). La masse moléculaire de l'enzyme native est de 75 kDa, elle est constituée par deux sous-unités identiques (35 kDa). Le phi, la température et le ph optimum d'action sont respectivement de 4,2, 50°C et 5,0. Cette neuraminidase est sensible à l'action de la température, elle n'est stable qu'en dessous de 48°C. L'activité est indépendante des métaux. Elle permet l'hydrolyse des liaisons alpha 2,3 plus rapidement que les alpha 2,6 et les alpha 2,8. L'enzyme agit aussi bien sur les glycopeptides que sur les glycoprotéines natives.
11
Arany, Catherine Beatrice \d 1968. "Enhanced recovery of injured and noninjured cells of Bifidobacterium species from water and dairy products /". This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-12162009-020131/.
Testo completo
12
Trindade, Marla. "Studies on carbohydrate metabolism in Bifidobacterium : isolation, characterisation and regulation of a sucrose-utilisation gene cluster in Bifidobacterium lactis". Doctoral thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/4341.
Testo completoAbstract (sommario):
Bibliography: leaves 167-195.The primary aim of the project was, therefore, to analyse carbohydrate metabolism for the identification of and/or the development of prebiotic substrates, and to provide a molecular characterisation for their utilisation. Several carbohydrates were tested for their ability to support the growth of bifidobacteria as a sole carbohydrate source. The four bifidobacterial strains, B. breve, B. bifidum, B. longum and B. lactis were able to utilise a wide variety of substrates.
13
Fachin, Luciano. "Contagem de Bifidobacterium animalis Bb 12 e efeito da adição de Propionibacterium freudenreichii PS-1 e do tratamento termico do leite sobre o desenvolvimento de Bifidobacterium animalis Bb 12 em iogurte". [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/255805.
Testo completoAbstract (sommario):
Orientadores: Walkiria Hanada Viotto, Mieko KimuraTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
Made available in DSpace on 2018-08-04T02:47:09Z (GMT). No. of bitstreams: 1 Fachin_Luciano_D.pdf: 623874 bytes, checksum: 39038138708fcb9d94eb3e5320272cbb (MD5) Previous issue date: 2005
Resumo: A produção de iogurtes com Bifidobacterium spp. tem crescido muito nas últimas décadas visando a produção de alimentos funcionais. Contudo, para que o produto possa apresentar tais propriedades, tem sido alegado que o número mínimo de células viáveis de Bifidobacterium spp. presentes no momento do consumo deva ser de 106 UFC/g de produto. Entretanto, vários estudos têm mostrado produtos comerciais com contagens menores do que as recomendadas, durante a estocagem do iogurte. Esse fato é reflexo tanto da dificuldade de incorporação destes microrganismos ao iogurte, devido às condições de processo que não são favoráveis ao desenvolvimento da bifidobactéria, bem como pela dificuldade de enumeração destes microrganismos na presença das culturas do iogurte. Este trabalho avaliou o uso dos meios M-MRS, MRS-NNLP, MRS-LP, RCPB pH5 e RCPB pH5 enriquecido com extrato de fígado, visando a contagem seletiva ou diferencial de Bifidobacterium animalis Bb 12 na presença das culturas do iogurte e estudou o efeito do tratamento térmico do leite, visando o aumento do teor de lactulose e, da adição de Propionibacterium freudenreichii PS-1, sobre o desenvolvimento e manutenção do número de células viáveis de B. animalis Bb 12 durante a fermentação e estocagem do iogurte. Dos meios estudados, o meio RCPB pH5, enriquecido com 150mL/L de extrato de fígado, foi o mais indicado para a contagem de B. animalis Bb 12 em iogurte por ter apresentado uma excelente diferenciação deste microrganismo, após a estocagem refrigerada do iogurte. O tratamento térmico do leite de 142°C/15 segundos não afetou o desenvolvimento de B. animalis Bb 12 durante a fermentação do iogurte e também não influenciou a sua resistência à estocagem refrigerada. Entretanto, o tratamento térmico alterou significativamente a textura, diminuindo consideravelmente a dureza, gomosidade e adesividade do iogurte, resultando em um produto com menor separação de soro. A adição de P. freudenreichii PS-1 aumentou em aproximadamente duas vezes o número de células de B. animalis Bb 12 ao final da fermentação e melhorou a resistência da bifidobactéria à estocagem refrigerada. A presença da propionibactéria também alterou significativamente a textura final do iogurte, aumentando consideravelmente a gomosidade e adesividade do produto final, bem como resultou em um iogurte com menor separação de soro durante a estocagem refrigerada
Abstract: Bifidobacterium spp. has been used to produce probiotic yoghurts due to its therapeutic properties. However, it has been claimed that the number of bifidobactéria in yoghurt at the time of consuming must be 106 CFU /g of product to perform their therapeutic functions. Many studies found a low recovery of bifidobactéria from commercial products during shelf life. The low viability of bifidobactéria can be attributed to the process conditions of yoghurt, which is not favorable to the growth of bifidobactéria, and to the difficulty for enumeration of bifidobactéria in the presence of yoghurt bacteria. The objectives of this work were to evaluate the following media: M-MRS, MRS-NNLP, MRS-LP, RCPB pH5 and fortified RCPB pH5 to enumerate B. animalis Bb 12 in yoghurt, and to evaluate the heat treatment of milk (142°C/15 seconds) and the addition of P. freudenreichii PS-1 on the growth of B. animalis Bb 12 during yoghurt fermentation and during shelf life. RCPB pH5 fortified with 150 mL/L of liver extract was the best media due to its excellent differentiation during refrigerated storage of yoghurt. The heat treatment of milk (142°C/15 seconds) did not have effect on the growth of bifidobactéria during fermentation and it also did not improve the bifidus viability during storage. Heat treatment, however, had a strong effect on yoghurt texture, decreasing the sineresis and some parameters of TPA (hardness, gumminess and adhesiveness). The addition of P. freudenreichii PS-1 increased two fold the bifidobactéria growing during yoghurt fermentation and it also increased the viability of bifidobactéria during yoghurt shelf life. The addition of P. freudenreichii PS-1 also decreased the sineresis and increased TPA parameters of hardness, gumminess and adhesiveness. Addition of P. freudenreichii PS-1 to the yoghurt seems to be a good growth promoter for B. animalis Bb 12
Doutorado
Tecnologia de Alimentos
Doutor em Tecnologia de Alimentos
14
Corneau, Nathalie. "Analyse moléculaire de trois plasmides de Bifidobacterium longum". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0020/MQ55844.pdf.
Testo completo
15
Gann, Reed N. "Host Signaling Response to Adhesion of Bifidobacterium infantis". DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/586.
Testo completoAbstract (sommario):
Investigations of the molecular binding partners of the probiotic bacterium Bifidobacterium longum subspecies infantis (B. infantis) and the pathogen Salmonella enterica subspecies enterica serovar Typhimurium LT2 (Salmonella ser. Typhimurium) found that these two very different bacteria bind gangliosides. However, these organisms lead to completely different host health outcomes when present in the gut. B. infantis is the founding microbial population in the intestinal tract of breast-fed infants. S. typhimurium is the most important food-borne pathogen that results in humans. This study used an in vitro gut epithelial cell model to examine the host cellular response to adhesion of B. infantis, which led to an increase in intestinal epithelium survival. This observation led to a series of experiments to elucidate the pathway for host signaling initiated by adherence of B. infantis to the host membrane to explain the increase in host cell survival. B. infantis adhesion induced significant (q≤0.05) differential expression of 208 host genes. These genes were associated with increased broad mechanisms of cell survival that included BIRC3, TNFAIP3, and SERPINB9. We hypothesized that a biochemical link existed between the host membrane adhesion protein and the increase in cell survival, mediated via AKT. We tested this hypothesis to demonstrate that B. infantis interaction initiated signal transduction using G-proteins via phosphorylation of AKT and induced production of the BIRC3, TNFAIP3, and SERPINB9. This study discovered adhesion of B. infantis initiated activation of AKT via phosphorylation of both Ser473 and Thr308, which results in increased cell survival.
16
Centanni, Manuela <1984>. "Bifidobacterium - Human Host Interaction: Role of Human Plasminogen". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4677/1/Centanni_Manuela_tesi.pdf.
Testo completoAbstract (sommario):
Bifidobacterium is an important genus of the human gastrointestinal microbiota, affecting several host physiological features. Despite the numerous Bifidobacterium related health-promoting activities, there is still a dearth of information about the molecular mechanisms at the basis of the interaction between this microorganism and the host. Bacterial surface associated proteins may play an important role in this interaction because of their ability to intervene with host molecules, as recently reported for the host protein plasminogen. Plasminogen is the zymogen of the trypsin-like serine protease plasmin, an enzyme with a broad substrate specificity.
Aim of this thesis is to deepen the knowledge about the interaction between Bifidobacterium and the human plasminogen system and its role in the Bifidobacterium-host interaction process. As a bifidobacterial model, B. animalis subsp. lactis BI07 has been used because of its large usage in dairy and pharmaceutical preparations.
We started from the molecular characterization of the interaction between plasminogen and one bifidobacterial plasminogen receptor, DnaK, a cell wall protein showing high affinity for plasminogen, and went on with the study of the impact of intestinal environmental factors, such as bile salts and inflammation, on the plasminogen-mediated Bifidobacterium-host interaction. According to our in vitro findings, by enhancing the activation of the bifidobacterial bound plasminogen to plasmin, the host inflammatory response results in the decrease of the bifidobacterial adhesion to the host enterocytes, favouring bacterial migration to the luminal compartment. Conversely, in the absence of inflammation, plasminogen acts as a molecular bridge between host enterocytes and bifidobacteria, enhancing Bifidobacterium adhesion. Furthermore, adaptation to physiological concentrations of bile salts enhances the capability of this microorganism to interact with the host plasminogen system.
The host plasminogen system thus represents an important and flexible tool used by bifidobacteria in the cross-talk with the host.
17
Centanni, Manuela <1984>. "Bifidobacterium - Human Host Interaction: Role of Human Plasminogen". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4677/.
Testo completoAbstract (sommario):
Bifidobacterium is an important genus of the human gastrointestinal microbiota, affecting several host physiological features. Despite the numerous Bifidobacterium related health-promoting activities, there is still a dearth of information about the molecular mechanisms at the basis of the interaction between this microorganism and the host. Bacterial surface associated proteins may play an important role in this interaction because of their ability to intervene with host molecules, as recently reported for the host protein plasminogen. Plasminogen is the zymogen of the trypsin-like serine protease plasmin, an enzyme with a broad substrate specificity.
Aim of this thesis is to deepen the knowledge about the interaction between Bifidobacterium and the human plasminogen system and its role in the Bifidobacterium-host interaction process. As a bifidobacterial model, B. animalis subsp. lactis BI07 has been used because of its large usage in dairy and pharmaceutical preparations.
We started from the molecular characterization of the interaction between plasminogen and one bifidobacterial plasminogen receptor, DnaK, a cell wall protein showing high affinity for plasminogen, and went on with the study of the impact of intestinal environmental factors, such as bile salts and inflammation, on the plasminogen-mediated Bifidobacterium-host interaction. According to our in vitro findings, by enhancing the activation of the bifidobacterial bound plasminogen to plasmin, the host inflammatory response results in the decrease of the bifidobacterial adhesion to the host enterocytes, favouring bacterial migration to the luminal compartment. Conversely, in the absence of inflammation, plasminogen acts as a molecular bridge between host enterocytes and bifidobacteria, enhancing Bifidobacterium adhesion. Furthermore, adaptation to physiological concentrations of bile salts enhances the capability of this microorganism to interact with the host plasminogen system.
The host plasminogen system thus represents an important and flexible tool used by bifidobacteria in the cross-talk with the host.
18
Oliveira, Luiz Fernando Ferreira de. "Administração tópica do probiótico Bifidobacterium animalis subsp. lactis HN019 reduz a destruição tecidual periodontal em ratos com periodontite experimental: estudo histológico, microtomográfico, imunológico e microbiológico". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/58/58132/tde-24052016-092031/.
Testo completoAbstract (sommario):
O objetivo deste estudo foi avaliar os efeitos da administração tópica de bactérias probióticas do gênero Bifidobacterium na doença periodontal experimental em ratos. Foram utilizados 32 ratos divididos nos seguintes grupos: CT (controle), DPT (doença periodontal), CT-HN019 (controle + probiótico) e DPT-HN019 (doença periodontal + probiótico). No dia 0 do experimento, a doença periodontal foi induzida nos animais dos grupos DPT e DPT-HN019 por meio da colocação de ligaduras ao redor dos primeiros molares inferiores. Nos Grupos CT-HN019 e DPT-HN019, 2 mL de uma suspensão contendo 109 unidades formadoras de colônia/mL de Bifidobacterium animalis subsp lactis (B. lactis) HN019 foram administrados topicamente na região subgengival dos primeiros molares inferiores nos dias 0, 3 e 7 do experimento. Nos grupos CT e DPT, as administrações tópicas foram realizadas com uma suspensão sham (sem probiótico). Todos os animais foram submetidos à eutanásia 14 dias após o início do experimento. Foram coletados tecido gengival, hemi-mandíbulas e biofilme bucal para avaliação dos seguintes parâmetros: i) microbiota bacteriana (checkerboard DNA-DNA hybridization; ii) expressão de citocinas pró e anti-inflamatórias (análise Multiplex); iii) imunorreatividade de peptídeos antimicrobianos (reações imunohistoquímicas - estreptavidina-biotina-peroxidase); iv) níveis inserção conjuntiva (análise histomorfométrica) e v) microarquitetura e volume ósseos (microtomografia computadorizada por transmissão de raios X). Os dados obtidos foram submetidos à análise estatística (p < 0,05). O grupo DPT apresentou maiores valores de porosidade óssea, espaçamento de trabéculas ósseas e nível de inserção conjuntiva, bem como menor número de trabéculas e volume ósseos quando comparado a todos os outros grupos (p < 0,05). No Grupo DPT-HN019, foram observados maiores percentuais de bactérias dos complexos amarelo e azul, bem como maiores expressões de Osteoprotegerina (OPG), Beta-defensina (BD)-1, BD-2 e BD-3 quando comparados àqueles do Grupo DPT (p < 0,05). O Grupo DPT apresentou níveis de Interleucina (IL)-1β Receptor Ativador do Fator Nuclear Kappa-beta (RANKL) maiores que aqueles do Grupo DPT-HN019 (p < 0,05). As razões RANKL/OPG e IL-1β/IL-10 foram mais elevadas no grupo DPT do que no Grupo DPT-HN019 (p < 0,05). Dentro dos limites deste estudo pode-se concluir que o uso tópico de B. lactis HN019 promove um efeito protetor contra a perda óssea e de inserção conjuntiva decorrentes da periodontite experimental em ratos.The purpose of this study was to evaluate the effects of topical administration of probiotic bacteria of the genus Bifidobacterium on experimental periodontal disease in rats. 32 rats were divided into groups C (control), EP (experimental periodontitis), C-HN019 (control + probiotic) and EP-HN019 (EP+ probiotic). On day 0 of the experiment, periodontitis was induced in the animals of groups EP and EP-HN019 through the placement of ligatures around mandibular first molars. In groups C-HN019 and EP-HN019, 2 mL of suspensions containing 109 colony-forming units/mL of Bifidobacterium animalis subsp lactis (B. lactis) HN019 were topically administered in the subgingival region of mandibular first molars on days 0, 3 and 7 of the experiment. In groups C and EP, topical administrations were performed using a sham suspension (without probiotic). All animals were euthanized 14 days after the beginning of the experiment. Gingival tissue, hemi-mandibles and oral biofilm were collected for evaluation of the following parameters: i) bacterial microbiota (checkerboard DNA-DNA hybridization), ii) expression of pro- and anti-inflammatory cytokines (Multiplex analysis), iii) immunoreactivityof antimicrobial peptides (immunohistochemical reactions - streptavidin-biotin-peroxydase); iV) connective tissue attachment levels (histomorphometric analysis) and v) bone microarchitecture and volume (microtomographic analysis). Data were statistically analyzed (p < 0.05). Group EP presented greater values of bone porosity, trabecular separation and connective tissue attachment loss as well as reduced trabecular number and bone volume when compared with all the other groups (p < 0.05). In group EP-HN019, there were greater percentages of bacteria of the yellow and blue complexes and greater expressions of Osteoprotegerin (OPG) and beta-defensins (BD)-1, BD-2 and BD-3 when compared with group EP (p < 0.05). Group EP presented greater levels of Interleukin (IL)-1β and Receptor Activator of Nuclear Factor-Kappa B ligand (RANKL) than group EP-HN019 (p < 0.05). The increase in the ratios RANKL/OPG and IL-1β/IL-10 was greater in group EP than in group EP-HN019 (p < 0.05). Within the limits of the present study, it can be concluded that the topical use of B. lactis HN019 promotes a protective effect against alveolar bone and connective tissue attachment losses attributable to experimental periodontitis in rats.
19
Jayamanne, Vijith S. "Survival of probiotic Bifidobacterium spp. in fermented milk products". Thesis, University of Surrey, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.435219.
Testo completo
20
Liserre, Alcina Maria. "Microencapsulação de Bifidobacterium lactis para aplicação em leites fermentados". Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/9/9131/tde-26042016-181206/.
Testo completoAbstract (sommario):
Bifidobacterium spp. são microrganismos probióticos que podem ser incorporados em produtos alimentícios. Entretanto, para que seus efeitos benéficos à saúde humana ocorram, é necessário que o número de células viáveis na hora do consumo seja, no mínimo, 106UFC/g. As bifidobactérias são sensíveis à elevada acidez e, por isso, torna-se necessária a busca por métodos que possam proteger a integridade da célula, sendo um deles a microencapsulação. Em uma primeira etapa do trabalho, Bifidobacterium lactis foi encapsulado em micropartículas de alginato e alginato modificado (alginatoquitosana, alginato-quitosana-sureteric e alginato-quitosana-acryl-eze) e sua sobrevivência e liberação das micropartículas em fluidos simulados do trato gastrintestinal foram mensuradas utilizando-se soluções tampão com pH 1,5, 5,6 e 7,5, na presença e na ausência de pepsina (3g/L), pancreatina (1g/L) e bile (10g/L). A liberação de células das micropartículas teve uma relação direta com o pH do tampão. A microencapsulação aumentou a taxa de sobrevivência de B. lactis, em comparação com células não encapsuladas, em soluções tampão com pH 1,5 sem a presença de enzimas. Em suco gástrico simulado com enzimas digestivas, por outro lado, foi observado que a pepsina proporcionou um efeito protetor sobre as células de B. lactis, e nesse caso, as taxas de sobrevivência do microrganismo estavam diretamente relacionadas com o grau de injúria das células. Em uma segunda etapa do trabalho, leites fermentados com Streptococcus salivarius ssp. thermophilus e Lactobacillus delbrueckii ssp. bulgaricus foram enriquecidos com culturas de Bifidobacterium lactis submetidas a quatro tratamentos diferentes: desidratação em temperatura ambiente, liofilização/congelamento, encapsulação em alginatoquitosana e encapsulação em alginato-quitosana-acryl-eze. A população sobrevivente de B. lactis foi determinada semanalmente no leite fermentado e também após tratamento simulando condições do trato gastrintestinal. Os resultados indicaram que na ausência de pepsina, as populações de B. lactis foram reduzidas drasticamente após o contato com tampão pH 1,5, não sendo possível a detecção de células viáveis livres ou encapsuladas após 120 minutos de teste. A presença de pepsina influenciou positivamente a recuperação de células viáveis de B. lactis em todas as condições testadas, mas as culturas na forma desidratada apresentaram melhores resultados que as culturas microencapsuladas ou liofilizadas. No caso do leite fermentado contendo as células desidratadas, a população de B. lactis, após o tratamento em suco gástrico com enzimas, foi superior à detectada no produto antes desse tratamento. Conclui-se que a microencapsulação não foi eficiente para proteger B. lactis em leite fermentado contra injúrias causadas pelo trato gastrintestinal simulado.Bifidobacterium spp. are microorganisms that can be added to foods. However, the benefits for the human health occur when the numbers of viable cells in the moment of the consumption is at least 106CFU/g. Bifidobacteria are acid sensitive, and methods to protect cell integrity, such as microencapsulation, are needed. In the first part of the present study, Bifidobacterium lactis was encapsulated in microparticles of alginate and modified alginate (alginate-chitosan, alginate-chitosan-sureteric and alginate-chitosan-acryl-eze) and the survival and release from microparticles in simulated gastrointestinal conditions were measured, using buffers (pH 1.5, 5.6 and 7.5), in the absence and presence of pepsin (3g/L), pancreatin (1g/L) and bile. The release from microparticles presented a direct relationship with pH. When the pH was 1.5 and no enzyme was present, encapsulation improved the survival of B. lactis, when compared to free cells. However, pepsin had a protective effect on B. lactis, and the survival rate was directly related to the cells injury degree. In the second part of the study, fermented milk samples containing Streptococcus salivarius ssp. thermophilus and Lactobacillus delbrueckii ssp. Bulgaricus were supplemented with B. lactis submitted to four different treatments: dehydration at room temperature, freeze drying, encapsulation in alginate-chitosan and encapsulation in alginate-chitosaacryl-eze. The number of viable B. lactis cells in the fermented milk was determined weekly and also after treatment with simulated gastrointestinal conditions. Results indicated that in the absence of pepsin, the number of viable cells decreased significantly after contact with buffers (pH 1.5), and no viable cell was detected after 120 minutes. Pepsin improved the recovery of viable cells in the assayed gastric conditions, being the dehydrated cultures more resistant than other cultures. In fermented milk containing the dehydrated cells, the number of viable cells increased after treatment with simulated gastrointestinal fluids. Microencapsulation was not an effective procedure to protect B. lactis in fermented milk against injury caused by the simulated gastrointestinal tract.
21
Collado, Amores María Carmen. "Caracterización de cepas del género Bifidobacterium con carácter probiótico". Doctoral thesis, Universitat Politècnica de València, 2008. http://hdl.handle.net/10251/1907.
Testo completoAbstract (sommario):
El concepto de alimento funcional se emplea para describir a aquellos alimentos adicionados con ingredientes de diversas clases y orígenes que pueden ejercer efectos beneficiosos sobre quien los ingiere. Este concepto surgido en Japón ha ido popularizándose y expandiéndose hacia otros continentes como Europa fundamentalmente debido a la preocupación sobre la nutrición, la dieta y la salud de la sociedad actual. Los probióticos representan una gran área dentro de los alimentos funcionales y se ha intensificado la investigación para desarrollar productos probióticos y profundizar en el conocimiento de los efectos sobre la salud humana.
Los probióticos se definen como "suplementos alimentarios microbianos vivos que afectan de forma ventajosa al animal huésped mejorando su equilibrio intestinal microbiano". Son microorganismos que estimulan las funciones protectoras del tracto digestivo, y también son conocidos como bioterapéuticos, bioprotectores o bioprofilácticos, ya que se utilizan para prevenir las infecciones entéricas y gastrointestinales. Un microorganismo probiótico efectivo debe poseer una serie de características: no ha de ser no patógeno ni tóxico, debe ejercer efectos beneficiosos sobre la salud de quien lo ingiere, tener origen humano, ha de ser tecnológicamente utilizable, ha de presentar un elevado porcentaje de células viables, debe ser capaz de sobrevivir a la flora intestinal, ha de permanecer viable durante su almacenamiento en refrigeración, y tener capacidad de adherirse a la superficie mucosa, etc. El establecimiento de criterios de selección y controles de calidad para productos probióticos se considera una prioridad debido a la rápida incorporación de estos productos en el mercado y su distribución en el ámbito internacional sin la existencia previa de una normativa comúnmente aceptada.
En los últimos años ha aumentado el interés por los productos elaborados con microorganismos probióticos, pertenecientes a los géneros Lactobacillus y BifidobacCollado Amores, MC. (2005). Caracterización de cepas del género Bifidobacterium con carácter probiótico [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1907
Palancia
22
Freitas, Camila Maria de. "Efeito da administração de bactérias ácido-láticas sobre o ganho de peso de leitões na maternidade". Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/10/10135/tde-02122008-154629/.
Testo completoAbstract (sommario):
O experimento foi conduzido nas instalações de gestação e maternidade da Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo, em Pirassununga, para avaliar o efeito da administração de bactérias probióticas ácido-láticas sobre o ganho de peso de um determinado grupo de leitões logo após o nascimento e antes da primeira mamada do colostro. Para efeito de comparação, criou-se outro grupo de leitões placebo que receberam água destilada em igual volume e manejo. Todos os animais foram pesados semanalmente desde o nascimento até o desmame ocorrido com 21 dias de idade. Os intervalos de ganho de peso médio diário também foram considerados. O probiótico testado não foi eficiente em alterar significativamente o ganho de peso dos animais (P>0,05), porém os leitões que o receberam, obtiveram numericamente maior ganho de peso médio diário, bastante evidente aos 7 e 14 dias de idade, podendo-se justificar a hipótese da existência de uma economia de nutrientes aproveitados pelo hospedeiro que possuía uma microbiota estável e saudável.The experiment was carried in the gestation and farrowing environment of the Faculty of Veterinary Medicine and Zootechny at University of Sao Paulo, in Pirassununga, to evaluate the effect of lactic acid probiotic bacteria administration on weight gain of a specific group of piglets just after the birth and before first colostrum suckling. For a better comparison, we designed another group of piglets, placebo, which received distilled water in the same volume and manner as probiotic group. All the animals were weighed weekly since birth until weaning, occurred with 21 days old. The average daily weight gain ranges also were considered. The tested probiotic did not change efficiently the weight gain of the animals (P>0,05), however, probiotic treated animals had greater average daily weight gain counts, mainly obvious at 7 and 14 days old, being able to justify the hypothesis of the nutrients economy existence, used by the host, owner of a stable and healthy microbiota.
23
Carrasco, Leiva Carolina Andrea. "Diversidad de especies y genotipos de bifidobacterium en saliva y caries de niños chilenos de 7 a 11 años de edad con y sin caries". Tesis, Universidad de Chile, 2016. http://repositorio.uchile.cl/handle/2250/141803.
Testo completoAbstract (sommario):
Trabajo de Investigación Requisito para optar al Título de Cirujano DentistaINTRODUCCIÓN: La cavidad oral posee una microbiota residente característica, la cual, en un estado de equilibrio, coexiste en armonía con el hospedero y es beneficiosa para el mismo. Esta homeostasis bacteriana puede verse alterada al ser perturbado el hábitat, provocando un desequilibrio de la microbiota residente, lo que induce al desarrollo de patógenos oportunistas que facilitan el progreso de la caries dental, que corresponde a un proceso patológico mediado por bacterias, de origen multifactorial, altamente prevalente y costoso de tratar. Entre estos patógenos, han sido descritas ciertas especies del género Bifidobacterium, las cuales corresponden a bacterias Gram positivo, anaerobias, con propiedades acidogénicas y acidúricas, polimórficamente ramificadas, no móviles y no formadoras de esporas. A la fecha no existen estudios publicados sobre la diversidad de especies y genotipos de Bifidobacterium spp. en la cavidad oral de niños, ni de su asociación con caries. OBJETIVO: Analizar las diversidad de especies y genotipos de Bifidobacterium, en saliva y caries dentinaria de niños chilenos de 7 a 11 años de edad con caries y en saliva de niños libres de caries. MATERIAL Y MÉTODOS: Protocolo aprobado por el Comité de Ética de la Facultad de Odontología. Previo consentimiento de los padres, se tomaron muestras de saliva y caries a niños Chilenos de 7-11 años (9 sin caries y 9 con caries), en la Clínica Odontológica, Universidad de Chile. Las muestras fueron sembradas en el medio de cultivo Triptona - Fitona - Extracto de Levadura modificado (MTPY), selectivo para Bifidobacteriaceae, e incubadas 72 hrs a 37°C en anaerobiosis. De las colonias crecidas, se seleccionaron 16 al azar desde cada muestra, para aislamiento de ADN. A través de la realización de reacción en cadena de la polimerasa (PCR) con oligonucleótidos específicos para Bifidobacteriaceae y oligonucleótidos específicos para amplificación de un fragmento de ADN del gen de 16S rRNA bacteriano, en los casos que no amplificaron con oligonucleótidos específicos para Bifidobacteriaceae. El producto de PCR fue purificado y posteriormente se secuenciaron e identificaron las especies. Finalmente se diferenciaron los genotipos de las especies pertenecientes a la familia Bifidobacteriaceae, mediante PCR basado en secuencias repetitivas (REP-PCR) y se realizaron análisis estadísticos de los resultados. RESULTADOS: No se detectaron Bifidobacterium spp. en la cavidad oral de los sujetos de estudio, sin embargo se aislaron otras especies a partir del medio de cultivo MTPY. Actinomyces odontolyticus fue asociado a la saliva de los niños, independiente de su experiencia de caries. Rothia mucilaginosa se vio asociada a la cavidad oral de los sujetos libres de caries. Lactobacillus spp. se vio asociado a la cavidad oral de sujetos con experiencia de caries. Parascardovia denticolens estuvo fuertemente asociada a sitios de caries. CONCLUSIONES: No se logró validar ni refutar la hipótesis de trabajo del presente estudio, debido a que no fue posible aislar Bifidobacterium spp, desde las muestras de los sujetos participantes. Se encontró asociación entre algunas de las especies aisladas en este estudio, con la experiencia de caries de los sujetos y el tipo de muestra. Los aislados de Parascardovia denticolens presentaron una amplia variedad de genotipos, pero con un mismo origen filogenético.
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24
Stievenard, Sylvain. "Hydrolyse industrielle du lactose : mise au point au stade laboratoire d'un réacteur à lactase immobilisée". Lille 1, 1986. http://www.theses.fr/1986LIL10172.
Testo completoAbstract (sommario):
L'existence d'une activité lactasique chez un micro-organisme non pathogène nous a conduit à envisager la mise au point d'un procédé d'hydrolyse industrielle du lactose contenu dans le lait et les lactosérums. Notre démarche s'est appuyée sur plusieurs points : le procédé doit être facile à mettre en oeuvre industirellement et doit pouvoir se réaliser en continu. Il doit être en outre peu coûteux et conforme à la législation. La purification de la lactase est procédé qui s'est révélé être trop onéreux et déstabilisateur de l'activité enzymatique. Les cellules de ce microorganisme ont été incluses à l'intérieur d'un polymère d'origine naturelle. Nous avons comparé les paramétres enzymatiques de l'enzyme "libre" et "immobilisée". Le procédé mis au point au laboratoire est décrit, ses performances sont comparées à celles des autres systèmes existant déjà sur le marché.
25
Mangin, Irène. "Typage moléculaire de souches du genre bifidobacterium : polymorphisme génétique intraspécifique et intragénérique". Nancy 1, 1994. http://docnum.univ-lorraine.fr/public/SCD_T_1994_0123_MANGIN.pdf.
Testo completoAbstract (sommario):
L'identification des espèces ou des souches bactriennes repose sur la mise en évidence du polymorphisme génétique interspécifique et intra générique. Le but de ce travail a donc été de rechercher diverses méthodes de révélation du polymorphisme génétique, applicables au genre bifidobacterium. La réalisation de profils de restriction a d'abord permis une caractérisation des différentes souches du laboratoire, comprenant des souches de collection, des souches industrielles ainsi que des souches d'origine humaine provenant d'une expérience clinique. Cette première méthode révèle un polymorphisme de la taille des fragments de restriction aussi bien interspécifique qu'intra spécifique chez ce genre bactérien. Par ailleurs, une comparaison plus rapide des souches a été réalisée en utilisant une sonde nucléique spécifique des gènes d'ARN ribosomiques. Les profils obtenus ont notamment permis de caractériser toutes les souches de bifidobacterium et de procéder à des regroupements en espèces. Nous rapportons également l'identification de quatre espèces de bifidobacterium par la sélection de sondes nucléiques spécifiques d'espèces, isolées des mini-banques d'ADN des souches b. Adolescentis cip64. 59t, b. Animalis atcc25527#t, b. Bifidum cip64. 65 et b. Longum atcc15707#t. La spécificité d'espèce de ces fragments a été testée par hybridation sur les ADN natifs des souches du genre. Le polymorphisme de restriction existant entre les différentes souches de la même espèce a ensuite été visualisé par hybridation du fragment cloné sur les profils de restriction de l'ADN total. Ainsi, la sonde l6/45, spécifique de 13 des 15 souches classées dans l'espèce b. Longum uniquement, est répétée chez certaines de ces souches. Le séquençage de ce fragment a mis en évidence une partie d'orf. La séquence protéique déduite de cette orf présente des similarités significatives avec une classe de recombinases site-spécifiques représentées par la protéine Int du bactériophage lambda.
26
Bravo, Caba Marta Fernanda. "Presencia de factores de virulencia en miembros de la familia Bifidobacteriaceae aisladas desde cavidad oral de niños chilenos de 7 a 11 años". Tesis, Universidad de Chile, 2016. http://repositorio.uchile.cl/handle/2250/141599.
Testo completoAbstract (sommario):
Trabajo de Investigación Requisito para optar al Título de Cirujano DentistaINTRODUCCIÓN: La caries dental es una enfermedad crónica compleja y multifactorial, de componente infeccioso y de alta prevalencia en el ser humano. Se desarrolla producto de la interacción en el tiempo de una producción de ácidos a partir del metabolismo bacteriano, los dientes y la saliva. La microbiota que interactúa en este proceso es muy diversa. Estudios recientes han identificado a miembros de la familia Bifidobacteriaceae como microorganismos participantes de este proceso. Estos estudios son, en su mayoría, en adultos, y no existen análisis que relacionen estos microorganismos con niños. Por otra parte, las bacterias cariogénicas deben presentan mecanismos de patogenicidad para producir la enfermedad, entre los que se han descrito la aciduria, acidogénesis y la adhesión, todas codificadas por genes. En el presente estudio se buscará la presencia de estos mecanismos a partir de los genes ldh, gadB y spaA. OBJETIVO: Determinar la presencia de miembros de la familia Bifidobacteriaceae en saliva y caries de niños Chilenos entre 7 y 11 años de edad y analizar los genes que codifican para los factores de virulencia ldh, gadB y spaA. METODOLOGÍA: Mediante examen clínico, se seleccionó un grupo de 18 niños, 9 niños sin experiencia de caries y 9 con experiencia de caries. Se tomaron muestras de saliva de ambos grupos y muestras de sitio con caries en dentina a niños con experiencia de caries. Se procedió a realizar cultivos en medio MTPY, selectivo para Bifidobacteriaceae. Se aisló ADN genómico desde aislados clínicos seleccionados al azar, se realizó PCR para amplificar un fragmento del ADN del gen 16S ARNr y fueron enviados para su secuenciación. El análisis de estas secuencias permitió identificar las especies presentes en cada muestra. La presencia de los factores de virulencia se realizó por PCR, utilizando partidores específicos para cada gen en análisis (ldh, gadB y spaA). RESULTADOS: Se detectó Parascardovia denticolens, miembro de la familia Bifidobacteriaceae, en el 5,6% de los niños estudiados (n=18). Mediante PCR se determinó que de los aislados clínicos obtenidos, el 50% dió positivo para el factor de virulencia ldh mientras que para los factores de virulencia gadB y spaA no fue posible obtener un amplificado positivo. No se obtuvieron aislados clínicos para otras especies de Bifidobacteriaceae. La especie Actinomyces odontolyticus fue encontrada abundantemente en muestras de saliva del grupo de niños con experiencia de caries y sin experiencia de caries. Se determinó una asociación estadísticamente significativa de este microorganismo a las muestras de saliva de ambos grupos, al comparar con su presencia en los sitios con caries (p=0,01 y p=0,001). Rothia mucilaginosa se encontró asociada a las muestras de saliva en ausencia de experiencia de caries al comparar con su presencia en sitios con caries (p=0,001). CONCLUSIONES: En niños Chilenos entre 7 y 11 años sólo fue posible detectar la presencia de P. denticolens desde sitios con caries, única especie de los siete géneros de la familia Bifidobacteriaceae. Los aislados clínicos de P. denticolens codifican el gen Idh en un 50% de los aislados, mientras que no codifican para los genes spaA y gadB, por lo que estos aislados no usarían estos mecanismos descritos para la adhesión y resistencia de ambientes ácidos. Se encontraron otras especies bacterianas asociadas al tipo de muestra, como A. odontolyticus encontrada en saliva tanto de niños libres de caries como con experiencia de caries. De este mismo modo existen especies bacterianas relacionadas a la ausencia de caries, como R. mucilaginosa.
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27
Adhikari, Koushik. "Viability and metabolic activity of encapsulated bifidobacteria in yogurt /". free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9999266.
Testo completo
28
Cho, Young-Jae. "Investigation of the functionality of probiotic fortified soy beverages : in vitro and and in vivo studies /". free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p3144409.
Testo completo
29
Meyer, Catherine. "Les bifidobacteries : proprietes, role nutritionnel, applications dietetiques". Strasbourg 1, 1992. http://www.theses.fr/1992STR15019.
Testo completo
30
Hung, Ming-Ni 1962. "Biochemical and genomic analysis of -galactosidases from Bifidobacterium infantis HL96". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36953.
Testo completoAbstract (sommario):
Among 29 strains of bifidobacteria studied as sources of beta-galactosidase enzyme, Bifidobacterium infantis HL96 showed the highest hydrolytic and transgalactosylic activities. This strain grew well in a MRS medium containing various sugars including lactose, and produced three beta-galactosidases (termed beta-Gal I, II, III).Two genes, beta-galI and beta-galIII, located on 4.6 and 4.4 kb DNA fragments respectively, were cloned into E. coli, and the nucleotide sequences were determined. The 3,069 by-long beta-galI, encoded a polypeptide with a Mr of 113 kDa. A putative ribosome-binding site and a promoter sequence were recognized at the 5' flanking region of beta-galI. A partial sequence of an ORF transcribing divergently from beta-galI resembled a lactose permease gene. The beta-galIII gene, which is 2,076 bp long, encoded a polypeptide with a Mr of 76 kDa. A rho-independent, transcription terminator-like sequence was found 25 bp downstream of the termination codon.
The amino acid sequences of beta-GalI and beta-GalIII were homologous to those in the LacZ and LacG families, respectively. The acid-base, nucleophilic, and substrate recognition sites conserved in the LacZ family were found in beta-GalI, and a possible acid-base site proposed for the LacG family was located in beta-GalIII, containing a glutamate at residue 160. beta-GalI and beta-GalIII were over-expressed 35 and 96 times respectively in E. coli by using a pET expression system.
Both beta-GalI and beta-GalIII were specific for beta-D -anomeric linked galactosides, but beta-GalI showed more hydrolytic and synthetic activities toward lactose than beta-GalIII. The galacto-oligosaccharides (GaOS) production mediated by beta-GalI at 37°C in 20% (w/v) lactose was 130 mg/ml, which is six times higher than that of beta-GalIII. The yield of GaOS further increased to 190 mg/ml in 30% (w/v) lactose. A major tri-saccharide produced by beta-GalI was characterized as O-beta- D-galactopyranosyl-(1-3)-O-beta-D-galactopyranosyl-(1-4)- D-glucopyranose.
beta-GalI was purified by ammonium sulphate precipitation, and anion-exchange (Mono-Q) and gel filtration (Superose 12) chromatographic steps. The enzyme appeared to be a tetramer, with a Mr of 470 kDa as estimated by native PAGE and gel-filtration chromatography. The optimum temperature and pH for ONPG and lactose as substrates were 60°C, pH 7.5, and 50°C, pH 7.5, respectively. The enzyme was stable over the pH range of 5~8.5, and was particularly active at 50°C for more than 80 min. The enzyme was significantly activated by reducing agents, especially glutathione, as well as by Na+ and K+ cations. Maximal activity required both Na+ and K+ at a concentration of 10 mM. The enzyme was strongly inhibited by p-chloromercuribenzoic acid, and by most bivalent metal ions. Hydrolytic activity using 20 mM lactose as substrate was significantly inhibited by 10 mM galactose. The Km and Vmax values for ONPG and lactose were 2.6 mM, 262 U/mg, and 73.8 mM, 1.28 U/mg, respectively.
The objectives of this research were to characterize beta-galactosidases of B. infantis HL96 at the molecular and biochemical levels, and to over-express the enzymes in Escherichia coli. Two beta-galactosidase isoenzymes with unique properties were genetically characterized for the first time. beta-GalI properties included a neutral pH optimum, relatively higher temperature stability and a high transgalactosylic activity that makes it very competitive for GaOS synthesis. The results were also important for the advancement of knowledge on the catalytic mechanism and the evolutionary aspect of this enzyme.
31
Krzewinski, Frédéric. "Transport et métabolisme des saccharides chez Bifidobacterium bifidum SM 20082". Lille 1, 1997. http://www.theses.fr/1997LIL10005.
Testo completoAbstract (sommario):
Nous avons etudie la capacite de bifidobacterium bifidum dsm 20082 a assimiler des saccharides. Cette etude a ete realisee en utilisant la technique de microcalorimetrie. Les resultats obtenus montrent que bifidobacterium bifidum est capable de croitre sur milieu riche (tpy) en presence ou en absence de saccharides. Sur milieu semi-synthetique (garches modifie), seules les n-acetylhexosamines permettent une croissance bacterienne, elles sont donc assimilees comme seule source de carbone. De plus, la quantite de chaleur degagee est proportionnelle a la consommation du saccharide. Les facteurs bifidogenes ne sont en realite que des nutriments preferentiels des bifidobacteries. Nous nous sommes interesses ensuite aux mecanismes d'incorporation de differents saccharides, glucose, fructose, galactose, n-acetylglucosamine, lactose et lacto-n-biose. La determination du mecanisme de transport de chaque saccharide a ete realisee a l'aide d'inhibiteur de translocation et de l'etude de la phosphorylation des saccharides. Les six mecanismes de transport se sont averes etre constitutifs. Le saccharide utilise lors de la culture n'entraine qu'une adaptation de la bacterie au saccharide, voire aucun changement dans la capacite d'incorporation. Les systemes de transport montrent une grande specificite vis-a-vis du saccharide qu'ils transportent. Le glucose est vehicule par un symport a cation regule par les ions potassium, avant d'etre phosphoryle par une glucokinase atp-independante. Le galactose traverserait la membrane par un mecanisme de diffusion. La galactokinase est activee en presence d'atp. Le lacto-n-biose et le lactose sont incorpores par des symports a proton. La -d-galactosidase est presente en grande quantite au niveau intracellulaire afin de liberer le glucose et le galactose. Le fructose est vehicule par un symport a proton. La fructokinase voit son activite diminuer de 60% en presence d'atp. Bifidobacterium bifidum aurait trouve a ce niveau un moyen de reguler le transport du fructose par un mecanisme de retro-inhibition.
32
Липовська, Вікторія Вікторівна, Виктория Викторовна Липовская, Viktoriia Viktorivna Lypovska e К. Ю. Ковальчук. "Зміни вмісту Bifidobacterium bifidum у хворих на шигельоз та сальмонельоз". Thesis, Видавництво СумДУ, 2009. http://essuir.sumdu.edu.ua/handle/123456789/4716.
Testo completoAbstract (sommario):
У даний час захворюваність на шигельоз та сальмонельоз серед дітей посідає одне з провідних місць у інфекційній патології. У зв‘язку з цим надзвичайно важливим є питання епідеміологічного моніторингу, який включав би не тільки спостереження за циркуляцією основних збудників кишкових інфекцій, вивчення змін їх біологічних, культуральних та лізабельних властивостей, але й оцінював би їх вплив на мікробіоценоз шлунково-кишкового тракту.
При цитуванні документа, використовуйте посилання http://essuir.sumdu.edu.ua/handle/123456789/4716
33
Tu, Liwen. "Cloning and sequence analysis of multiple genes from Bifidobacterium infantis /". free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p3137758.
Testo completo
34
Tacconi, Stefano <1961>. "Rapporti fra fattori ambientali e proteine di parete in Bifidobacterium". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/2041/1/tacconi_stefano_tesi.pdf.
Testo completoAbstract (sommario):
The normal gut microbiota has several important functions in host physiology and metabolism, and plays a key role in health and disease. Bifidobacteria, which are indigenous components of gastrointestinal microbiota, may play an important role in maintaining the well-being of the host although its precise function is very difficult to study. Its physiological and biochemical activities are controlled by many factors, particularly diet and environment.
Adherence and colonization capacity are considered as contributing factors for immune modulation,
pathogen exclusion, and enhanced contact with the mucosa. In this way, bifidobacteria would fortify the microbiota that forms an integral part of the mucosal barrier and colonization resistance against pathogens.
Bifidobacteria are not only subjected to stressful conditions in industrial processes, but also in nature, where the ability to respond quickly to stress is essential for survival. Bifidobacteria, like other microorganisms, have evolved sensing systems for/and defences against stress that allow them to withstand harsh conditions and sudden environmental changes.
Bacterial stress responses rely on the coordinated expression of genes that alter various cellular processes and structures (e.g. DNA metabolism, housekeeping genes, cell-wall proteins, membrane composition) and act in concert to improve bacterial stress tolerance. The integration of these stress responses is accomplished by regulatory networks that allow the cell to react rapidly to various and sometimes complex environmental changes. This work examined the effect of important stressful conditions, such as changing pH and osmolarity, on the biosynthesis of cell wall proteins in B. pseudolongum subsp. globosum. These environmental factors all influence heavily the expression of BIFOP (BIFidobacterial Outer Proteins) in the cell-wall and can have an impact in the interaction with host. Also evidence has been collected linking the low concentration of sugar in the culture medium with the presence or absence of extracromosomal DNA.
35
Tacconi, Stefano <1961>. "Rapporti fra fattori ambientali e proteine di parete in Bifidobacterium". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/2041/.
Testo completoAbstract (sommario):
The normal gut microbiota has several important functions in host physiology and metabolism, and plays a key role in health and disease. Bifidobacteria, which are indigenous components of gastrointestinal microbiota, may play an important role in maintaining the well-being of the host although its precise function is very difficult to study. Its physiological and biochemical activities are controlled by many factors, particularly diet and environment.
Adherence and colonization capacity are considered as contributing factors for immune modulation,
pathogen exclusion, and enhanced contact with the mucosa. In this way, bifidobacteria would fortify the microbiota that forms an integral part of the mucosal barrier and colonization resistance against pathogens.
Bifidobacteria are not only subjected to stressful conditions in industrial processes, but also in nature, where the ability to respond quickly to stress is essential for survival. Bifidobacteria, like other microorganisms, have evolved sensing systems for/and defences against stress that allow them to withstand harsh conditions and sudden environmental changes.
Bacterial stress responses rely on the coordinated expression of genes that alter various cellular processes and structures (e.g. DNA metabolism, housekeeping genes, cell-wall proteins, membrane composition) and act in concert to improve bacterial stress tolerance. The integration of these stress responses is accomplished by regulatory networks that allow the cell to react rapidly to various and sometimes complex environmental changes. This work examined the effect of important stressful conditions, such as changing pH and osmolarity, on the biosynthesis of cell wall proteins in B. pseudolongum subsp. globosum. These environmental factors all influence heavily the expression of BIFOP (BIFidobacterial Outer Proteins) in the cell-wall and can have an impact in the interaction with host. Also evidence has been collected linking the low concentration of sugar in the culture medium with the presence or absence of extracromosomal DNA.
36
Satti, Maria Altaf <1991>. "Comparative Analysis of Genus Bifidobacterium: Insight into its Host Adaptation". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9892/1/Doctoral%20Thesis.pdf.
Testo completoAbstract (sommario):
Bifidobacteria is amongst one of the health promoting bacteria. The role of this important probiotic genera can be elucidated by understanding its genome. Comparative analysis of the whole genus of these bacteria can reveal their adaptation to a diverse host range.
This study comprises of four research projects. In the first study, a reference library for genus Bifidobacterium was prepared. The core genes in each genus were selected based on a newly proposed statistical definition of core genome. Comparative analysis of Bifidobacterium with another probiotic genus Lactobacillus revealed the metabolic characteristics of genus Bifidobacterium.
The second study investigated the immunomodulatory role of a B. bifidum strain TMC3115. The analysis of TMC3115 provided insights into its extracellular structures which might have their role in host interaction and immunomodulation. The study highlighted the variability among these genomes just not on species level but also on strain level in terms of host interaction.
The last two studies aim to inspect the relationship between bifidobacteria and its host diet. Bifidobacteria, are both host- and niche-specific. Such adaptation of bifidobacterial species is considered relevant to the intestinal microecosystem and hosts’ oligosaccharides. Many species should have co-evolved with their hosts, but the phylogeny of Bifidobacterium is dissimilar to that of host animals. The discrepancy could be linked to the niche-specific evolution due to hosts’ dietary carbohydrates. The distribution of carbohydrate-active enzymes, in particular glycoside hydrolases (GHs) that metabolize unique oligosaccharides was examined. When bifidobacterial species were classified by their distribution of GH genes, five groups arose according to their hosts’ feeding behaviour. The distribution of GH genes was only weakly associated with the phylogeny of the host animals or with genomic features such as genome size. Thus, the hosts’ dietary pattern is the key determinant of the distribution and evolution of GH genes.
37
Martin, Laurence. "Modulation des propriétés des cellules dendritiques humaines par un surnageant de bactérie probiotique : induction de lymphocytes T régulateur". Thesis, Tours, 2008. http://www.theses.fr/2008TOUR3107.
Testo completoAbstract (sommario):
Les cellules de notre système immunitaire différencient les antigènes du Soi, envers lesquels elles ne doivent pas engendrer de réponse immunitaire effectrice, et les pathogènes qu’elles doivent éliminer. Outre les antigènes du Soi, le système immunitaire doit également tolérer des antigènes de l’environnement non pathogènes comme les aliments et les bactéries de la flore commensale qui colonisent l’intestin. Au sein de cette flore se trouvent des bactéries « probiotiques » dont certaines souches ont un effet préventif et/ou curatif dans le cadre d’allergies, de maladies inflammatoires ou même de cancers. Ces effets seraient au moins en partie dus à une action des probiotiques ou de leurs métabolites sur des cellules du système immunitaire. Les cellules dendritiques (DC) ont une grande plasticité qui leur permet, selon les signaux qu’elles perçoivent, de générer soit une réponse immunitaire effectrice pour éliminer les pathogènes soit une tolérance en induisant des lymphocytes T régulateurs. On les retrouve notamment au niveau de la muqueuse intestinale où elles sont susceptibles d’interagir avec les probiotiques. Nous avons analysé l’impact d’un surnageant de fermentation d’un milieu laitier simplifié par la bactérie probiotique Bifidobacterium breve C50 (BbC50sn) sur les DC humaines in vitro : ce surnageant entraîne la maturation de ces cellules (DC-BbC50sn) ainsi qu’une forte production d’IL-10 et une augmentation de leur survie via le TLR-2. L’analyse des gènes transcrits dans les DC-BbC50sn par la technique des puces à ADN met en évidence l’expression de gènes codant des molécules tolérogènes comme ILT-3, ILT-4 et PDL-1. De plus, nous montrons que les DC-BbC50sn induisent des lymphocytes T (LT) régulateurs fonctionnels in vitro. Ces LT régulateurs secrètent de l’IL-10 et du TGF-ß et nécessitent une activation spécifique d’alloantigène par des DC pour exercer leur activité suppressive. Nous avons également montré l’induction de LT régulateurs ayant des caractéristiques différentes par des DC traitées avec d’autres ligands de TLR-2 et TLR-4. Nous démontrons donc que BbC50sn peut avoir des capacités régulatrices au travers de son action sur les cellules dendritiques humaines en induisant des lymphocytes T régulateurs in vitro. Ces résultats représentent une base rationnelle de son utilisation en cliniqueThe immune system protects our organism by removing pathogen bacteria and viruses while tolerating non-pathogenic antigens from self, environment and commensal bacteria. Some commensal bacteria called “probiotics” have been shown to exert beneficial effects on the host health. Recent studies demonstrated that these probiotic bacteria could act on immune cells either directly or via their metabolites. Dendritic cells (DC) are able to induce either an effective or a tolerogenic immune response depending on the environment signals. They can be found in the intestinal mucosa where they could interact with probiotic bacteria. We demonstrated that a bacteria-free fermentation product of Bifidobacterium breve C50 (BbC50sn) induced human DC maturation with high IL-10 production in vitro and prolonged their survival. The BbC50sn action on dendritic cells was mediated via the TLR-2 pathway. The DNA microarray analysis showed that BbC50sn-DC produced high levels of mRNA corresponding to genes encoding tolerogenic molecules such as ILT-3, ILT-4 and PDL-1. We also highlighted that these BbC50sn-DC could induce functional regulatory T cells in vitro. These regulatory T cells needed an alloantigen specific activation to exert their suppressive activity and didn’t act through a T cell-T cell contact. These regulatory T cells secreted IL-10 and TGF-ß; however, these cytokines didn’t appear to mediate the suppressive activity. We also showed that other dendritic cells treated with TLR-2 and TLR-4 ligands could induce regulatory T cells different from those induced by BbC50sn-DC. BbC50sn is thus able to exert a regulatory effect through this action on human dendritic cells by inducing regulatory T cells in vitro. As far as we know, it is the first demonstration of regulatory T cell induction by a probiotic derivative product. These results represent a rational basis for BbC50sn use in clinics
38
Kim, Geun-Bae 1966. "Biochemical and genomic analysis of bile salt hydrolases from Bifidobacterium strains". Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84272.
Testo completoAbstract (sommario):
Three different types (A, B, and C) of bile salt hydrolase from different Bifidobacterium strains revealed during the purification study showed the type-specific characteristics in their electrophoretic migration and elution profiles from anion exchange and hydrophobic interaction chromatographic columns. The subunit molecular mass estimated by SDS-PAGE was around 35 kDa and the native molecular mass in all types of BSH was estimated to be between 130 and 150 kDa by gel filtration chromatography, indicating that all BSH enzymes have tetrameric structure. From the isoelectric focusing, pI value of 4.45 was obtained with type B, but type A and C BSHs showed similar pI values of around 4.65. While the N-terminal amino acid sequences of types A and B were highly homologous (19/20), six out of twenty amino acid residues were different in the N-terminal sequences of types A and C.As the type A bsh gene was cloned from a strain of B. longum and the nucleotide sequence became available from the GenBank, our study has focused on the cloning and characterization of the type B and C bsh genes from Bifidobacterium strains.
The type B bsh gene was cloned from B. bifidum ATCC11863 and the DNA flanking the bsh gene was sequenced. The 951 by-long bsh gene encoded a 316-amino-acid protein with a molecular mass of 35 kDa and a pI of 4.48. For the first time in the genus Bifidobacterium, the transcriptional start point of the bsh gene was identified by primer extension analysis. Furthermore, Northern blot analysis revealed that B. bifidum bsh was transcribed as a monocistronic unit, contrary to that of B. longum bsh. Despite a high level of sequence similarity among the bsh genes, a BSH type-specific primer set based on the variable regions of bsh genes was designed in order to differentiate B. bifidum strains from the other species of Bifidobacterium commonly detected in the human gut.
The type C bsh gene was cloned from a bile salt tolerant strain of Bifidobacterium and the DNA flanking the bsh gene was further identified by a thermal asymmetric interlaced PCR (TAIL-PCR) technique. The 945 by-long bsh gene encoded a 314-amino-acid protein with a molecular mass of 35 kDa and a pI of 4.71. A predicted BSH promoter (Pbsh) sequence was experimentally verified and the transcriptional start point of the type C bsh gene was determined by primer extension analysis. An operonic structure including the type C bsh gene and two more ORFs, which were found within a complete set of a promoter and a transcription terminator, was identified in this study for the first time in the genus Bifidobacterium, and the polycistronic bsh transcript was revealed by RT-PCR and Northern blot analysis.
39
Savard, Patricia. "L'expression des gènes responsables du catabolisme de l'arabinoxylane chez Bifidobacterium longum". Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24549/24549.pdf.
Testo completo
40
Audy, Julie. "Approche transcriptionnelle pour l'étude de gènes chez Bifidobacterium longum CRC 002". Thesis, Université Laval, 2008. http://www.theses.ulaval.ca/2008/25448/25448.pdf.
Testo completo
41
Bull, Matthew J. "Molecular genetic characterisation of probiotic bacteria : Lactobacillus acidophilus and Bifidobacterium species". Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/53985/.
Testo completoAbstract (sommario):
Over time and concurrent development of methods to identify and characterise bacteria, the lactic acid bacteria (LAB) have undergone multiple taxonomic revisions. As a result of the revisionary nature of LAB taxonomy, the historical characterisation of Lactobacillus acidophilus has struggled with misidentification and misrepresentation. Now however, due to its global use in food products for both flavour and probiotic effect, L. acidophilus is now one of the most well physiologically characterised Lactobacillus species. Bifidobacterium bifidum and Bifidobacterium animalis subsp. lactis are also LAB that are considered to have probiotic effects. Here modern high-throughput next generation comparative genomic techniques are used alongside conventional biochemical and molecular typing methods to analyse the sub-species level diversity of these three probiotic species. Results Randomly Amplified Polymorphic DNA (RAPD) profile similarity analysis showed limited strain-level diversity of L. acidophilus. A species specific marker test was developed for L. acidophilus and used to search for L. acidophilus in wild rodent and human faeces. No L. acidophilus was detected in wild rodent faeces and its carriage in human faeces was highly variable. High-throughput next generation sequencing was used to resequence the genomes of 28 L. acidophilus isolates. Comparing these sequences indicated a high level of genomic conservation in L. acidophilus, which was reflected by limited phenotypic diversity. Comparative genomics in Bifidobacterium animalis subsp. lactis supported the hypothesis that it is a clonally monophyletic species, whereas B. bifidum strains were genomically diverse. Conclusions Methods for phenotypically characterising and typing LAB have generally been superseded in accuracy by DNA sequence based methods. Probiotic bacteria display a range of subspecies level population structures. Commercial and culture collection L. acidophilus isolates did not significantly differ phenotypically, but were distinct when their genome sequences are compared. B. bifidum was genotypically diverse at the subspecies level, while B. animalis subsp. lactis appeared to be clonally monophyletic. Comparative genomics and genome (re)sequencing of probiotic bacteria will become a “gold standard” method for characterisation and typing of isolates.
42
Martinez, Fabio Andres Castillo. "Produção de bacteriocina por Bifidobacterium lactis a partir de leite desnatado". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/9/9135/tde-16012014-134005/.
Testo completoAbstract (sommario):
Existe um número muito limitado de estudos referentes à produção de componentes antimicrobianos ou bacteriocinas produzidas por espécies de bifidobactérias. Nesse âmbito, o objetivo deste trabalho foi avaliar a produção de bifidobacteriocina em leite desnatado (LD). Para tanto, o estudo foi dividido em três etapas. A primeira etapa constituiu na preparação dos meios de cultura Man, Rogosa e Sharpe (MRS), Bifidus Selective Medium (BSM) e LD suplementado com 1% (p/v) de Tween 80 (T80), Inulina (I) ou Extrato de levedura (YE). Nesta etapa, os processos fermentativos foram conduzidos em shaker, nas condições: 50 rpm/37ºC/48h. Foram realizadas análises de pH, concentração de açúcares e ácidos, crescimento celular e determinação da atividade da bifidobacteriocina pelo método de difusão em ágar contra L. monocytogenes. Na segunda etapa, e baseado nos resultados obtidos, foi desenhado um delineamento composto central (CCD) construído a partir dos seguintes parâmetros: temperatura (34, 37, 40 °C) e concentração de YE (0,5; 1,0; 1,5 g/L). Na terceira etapa do trabalho, foram realizados os cultivos em biorreator de 2 L, contendo 10% de leite desnatado, nas seguintes condições: 200 rpm, 36°C, 2,0 g/L de YE, 48h de incubação em anaerobiose. Obteve-se em LD suplementado com YE (1%), combinado ao método de difusão em placa modificado (prévia refrigeração das placas por 12h), contra L. monocytogenes (2130 AU/mL), com uma fase exponencial de 24h, µm de 0,604/h. A otimização feita através do CCD permitiu atingir níveis de atividade de 3.000 AU/mL a 3.100 AU/mL (ensaios 7, 11 e 14, blocos 3 e 1) contra L. monocytogenes, em condições ótimas de crescimento de YE: 2,0 g/L1 e T°C: 36°C. A análise de regressão mostrou ser estatisticamente significativa a relação entre as variáveis: \"concentração de \"YE e temperatura\". Os resultados indicaram que o leite desnatado é um meio adequado para produção de bifidobacteriocina.There are few publications that have been reported about bacteriocin production by Bifidobacterium species. Therefore, the aim of this work was measure bacteriocin production in skim milk by B. lactis. Consequently, this work was divided in three stages. First, MRS, BSM and LD medium were tested with additives (Tween 80 (T80), Inuline (I) or Yeast extract (YE)) for bacteriocin production and cellular growth. Fermentation processes were conducted in shaker under specific conditions: 50 rpm/37ºC/48h. pH; sugars; acids; biomass, and bacteriocin activity against L. monocytogenes, L. plantarum, E. coli, L. sakei e S. aureus strains were analyzed . In the second stage, based on the obtained results, a central composite design (CCD) was created using the parameters: temperature (34, 37, 40 ºC), and concentration of YE (0.5, 1.0, 1.5 g/L). After, the activity was measured by two methods of plates pre-diffusion (cooling and addition of Tween 20). Third step consisted of 2 L bioreactor cultivations containing 10% skim milk diluted in 1.5 L of water (6.5 pH), under 200 rpm, 36 ºC, 2.0 g/L of YE, 48h, under anaerobic condition. Finally, the cultures supplemented with LD and YE (1%) with a modified plate diffusion method (cooling plates for 12 h) showed bacteriocin activity against L. monocytogenes (2130 AU/mL) with an exponential phase of 24 h, µm of 0.604/h. The optimization performed using CCD resulted in a higher level of activity 3000 AU/mL to 3100 AU/mL mL (Run 7, 11 and 14, blocks 3 and 1) against L. monocytogenes, also with ideal growth conditions of YE: 2,0 g/L1 and T °C: 36 °C. The pH value varied between 6.4 and 4.0. Concentration of produced acid lactic varied from 3.03 to 4.72 g/L and biomass concentration from 3.4 to 11.1 Lg UFC/mL. Regression analysis was significant to the variables: YE concentration and temperature. Results indicated that skim milk is a proper medium for \"Bifidobacteriocin\" production.
43
Stenico, Verena <1983>. "Genus Bifidobacterium: taxonomy studies and gene expression analysis on folate pathway". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6604/1/Stenico_Verena_tesi.pdf.
Testo completoAbstract (sommario):
Folates (vitamin B9) are essential water soluble vitamins, whose deficiency in humans may contribute to the onset of several diseases, such as anaemia, cancer, cardiovascular diseases, neurological problems as well as defects in embryonic development. Human and other mammals are unable to synthesize ex novo folate obtaining it from exogenous sources, via intestinal absorption. Recently the gut microbiota has been identified as an important source of folates and the selection and use of folate producing microorganisms represents an innovative strategy to increase human folate levels.
The aim of this thesis was to gain a fundamental understanding of folate metabolism in Bifidobacterium adolescentis. The work was subdivided in three main phases, also aimed to solve different problems encountered working with Bifidobacterium strains. First, a new identification method (based on PCR-RFLP of hsp60 gene) was specifically developed to identify Bifidobacterium strains. Secondly, Bifidobacterium adolescentis biodiversity was explored in order to recognize representing strains of this species to be screened for their folate production ability. Results showed that this species is characterized by a wide variability and support the idea that a possible new taxonomic re-organization would be required. Finally B. adolescentis folate metabolism was studied using a double approach. A quantitative analysis of folate content was complemented by the examination of expression levels of genes involved in folate related pathways. For the normalization process, required to increase the robustness of the qRT-PCR analysis, an appropriate set of reference genes was tested using two different algorithms. Results demonstrate that B.adolescentis strains may represent an endogenous source of natural folate and they could be used to fortify fermented dairy products. This bio-fortification strategy presents many advantages for the consumer, providing native folate forms more bio-available, and not implicated in the discussed controversy concerning the safety of high intake of synthetic folic acid.
44
Stenico, Verena <1983>. "Genus Bifidobacterium: taxonomy studies and gene expression analysis on folate pathway". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6604/.
Testo completoAbstract (sommario):
Folates (vitamin B9) are essential water soluble vitamins, whose deficiency in humans may contribute to the onset of several diseases, such as anaemia, cancer, cardiovascular diseases, neurological problems as well as defects in embryonic development. Human and other mammals are unable to synthesize ex novo folate obtaining it from exogenous sources, via intestinal absorption. Recently the gut microbiota has been identified as an important source of folates and the selection and use of folate producing microorganisms represents an innovative strategy to increase human folate levels.
The aim of this thesis was to gain a fundamental understanding of folate metabolism in Bifidobacterium adolescentis. The work was subdivided in three main phases, also aimed to solve different problems encountered working with Bifidobacterium strains. First, a new identification method (based on PCR-RFLP of hsp60 gene) was specifically developed to identify Bifidobacterium strains. Secondly, Bifidobacterium adolescentis biodiversity was explored in order to recognize representing strains of this species to be screened for their folate production ability. Results showed that this species is characterized by a wide variability and support the idea that a possible new taxonomic re-organization would be required. Finally B. adolescentis folate metabolism was studied using a double approach. A quantitative analysis of folate content was complemented by the examination of expression levels of genes involved in folate related pathways. For the normalization process, required to increase the robustness of the qRT-PCR analysis, an appropriate set of reference genes was tested using two different algorithms. Results demonstrate that B.adolescentis strains may represent an endogenous source of natural folate and they could be used to fortify fermented dairy products. This bio-fortification strategy presents many advantages for the consumer, providing native folate forms more bio-available, and not implicated in the discussed controversy concerning the safety of high intake of synthetic folic acid.
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Souza, Cínthia Hoch Batista de. "Desenvolvimento de margarina probiótica e simbiótica: viabilidade do probiótico no produto e resistência in vitro". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/9/9133/tde-17112010-174506/.
Testo completoAbstract (sommario):
O presente trabalho teve como objetivo verificar a viabilidade da cepa probiótica Bifidobacterium animalis subsp. lactis Bb-12 incorporado em margarina, suplementada com inulina, concentrado protéico de soro (WPC) e concentrado de caseína (CMP), bem como avaliar as características do produto e a resistência do probiótico às condições simuladas do trato gastrintestinal humano. Foram produzidos 7 diferentes tipos de margarinas de mesa (60% de lipídios: 60 % de óleo de palma + 40% de óleo de canola), empregando-se um modelo de mistura, onde inulina, WPC e CMP foram as variáveis estudadas. Uma formulação controle foi produzida (M8), sem adição desses ingredientes. A utilização da mistura do óleo de palma com óleo de canola favoreceu nutricionalmente as formulações, fornecendo produtos contendo ácidos graxos essenciais em sua composição e ausência de ácidos graxos trans. As formulações M1 a M7, exceto a formulação M2 após o 21º dia de armazenamento, apresentaram populações satisfatórias de Bb-12 para um alimento probiótico, com populações acima de 6 log UFC/g durante 35 dias de armazenamento. Margarinas suplementadas com inulina apresentaram populações satisfatórias durante todo o armazenamento, atingindo populações de 8,01 log UFC/g ao 35º dia (M1). Além disso, M3 e M6, revelaram populações de Bb-12 de 6,87 log UFC/g e 7,27 log UFC/g (dia 35), respectivamente. Por outro lado, M8 não foi caracterizada como margarina probiótica, uma vez que apresentou populações abaixo de 6 log UFC/g, já ao 1º dia de armazenamento. Embora WPC seja utilizado em pesquisas para aumentar a viabilidade de probióticos em alimentos, a suplementação de margarina com WPC sem inulina ou CMP não resultou em populações satisfatórias de Bb-12, apresentando decréscimo de 7,82 (dia 1) para 4,64 log UFC/g (M2, dia 35) (p<0,05). Durante todo o ensaio de resistência in vitro, Bb-12 apresentou sobrevivência significativamente superior (p<0,05) em M1 e revelou populações acima de 6 log UFC/g após 6h de ensaio mesmo ao 28º dia. As populações observadas para M2 diminuíram drasticamente durante o ensaio in vitro (5 log UFC/g após 2h no dia 7). Para as outras formulações, as populações de Bb-12 diminuíram 2 log UFC/g após 2h de ensaio in vitro. Entretanto, M1, M2 e M5 (dias 14 e 28) revelaram aumento significativo nas populações de Bb-12 (p<0,05) entre a fase gástrica (2h) e a segunda fase entérica (6h). As margarinas suplementadas com inulina, principalmente M1, revelaram decréscimo significativo no pH durante todo o armazenamento (p<0,05). Entretanto, isto não afetou a qualidade sensorial dos produtos, uma vez que não foram detectadas diferenças significativas entre as formulações após 7 e 14 dias de armazenamento (p>0,05). A suplementação de margarina com inulina e CMP garantiu populações apropriadas de Bb-12 durante o armazenamento estudado pelo menos até o 28º dia. Além disso, contribuiu para sua sobrevivência durante o ensaio de resistência in vitro. Os resultados revelaram que a margarina apresenta-se como uma matriz alimentar adequada para administração de Bb-12, principalmente quando a inulina foi adicionada.This study aimed to determine the viability of probiotic Bifidobacterium animalis subsp. lactis Bb-12 incorporated in margarine, with inulin, whey protein concentrate (WPC) and caseinomacropeptide (CMP) supplementation. In addition, the in vitro resistance of Bb-12 incorporated in margarine and related properties were evaluated. Seven margarine-making trials (60% of fat: 60% of palm oil +40% canola oil) were produced, using a mixture model, where inulin, WPC and CMP were the variables studied. Also, a control formulation without these ingredients was manufactured. The use of blending palm oil with canola oil improved the margarine formulations nutritionally, providing products containing essential fatty acids in its composition and absence of trans fatty acids. The formulations M1 to M7, except M2 after 21 days of storage, revealed satisfactory Bb-12 populations for a probiotic food, with counts above 6 log CFU/g during 35 days of storage at 5±1ºC. Margarines supplemented with inulin presented suitable Bb-12 populations throughout the whole storage period, reaching up to 8 log CFU/g by the end of storage (M1). Also, M3 and M6, revealed Bb-12 populations of 6.87 log CFU/g and of 7.27 log CFU/g (day 35), respectively. In contrast, M8 was not characterized as probiotic margarine, since it showed Bb-12 populations below 6 log CFU/g on day 1. Even though whey protein is largely employed in probiotic foods, margarine supplementation with WPC without inulin or CMP did not lead to Bb-12 satisfactory populations, decreasing from 7.82 (day 1) to 4.64 log CFU/g (M2, day 35) (p<0.05). During the whole in vitro assays, Bb-12 survived significantly better (p<0.05) in M1 and revealed populations above 6 log CFU/g after 6h even after 28 days. M2 populations decreased drastically during the in vitro assays for all storage period tested (reduction of 5 log CFU/g after 2h of in vitro assays on day 7 and populations of 2.8 log CFU/g after 6h). For the other formulations, Bb-12 populations decreased 2 log CFU/g after 2h of the in vitro assays. However, for M1, M2 and M5 (on day 14 and 28) the populations of Bb-12 increased significantly (p<0.05) between the gastric phase (2h) and the enteric phase (6h). Formulations containing inulin, mainly M1, showed a significant decrease in pH values during the whole storage period (p<0.05). However, this ingredient did not affect the sensory quality of products, since no significant differences between formulations after 7 and 14 days of storage were observed (p>0.05). The supplementation of margarine with inulin and CMP guaranteed appropriate Bb-12 populations during storage for at least 28 days, and also contributed for its survival throughout the in vitro assays. Therefore, margarine might be considered an appropriate food matrix for Bb-12 survival, mainly when inulin is also added.
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Inturri, Rosanna. "Caratterizzazione microbiologica di ceppi di Bifidobacterium spp. e analisi chimica e biologica di un esopolisaccaride prodotto". Doctoral thesis, Università di Catania, 2016. http://hdl.handle.net/10761/3921.
Testo completoAbstract (sommario):
Lo scopo della ricerca è stato quello di studiare le caratteristiche microbiologiche di ceppi di Bifidobacterium spp. isolati da feci umane e animali e da prodotti probiotici e quello di investigare le proprietà chimico-fisiche e alcune possibili attività biologiche dell esopolisaccaride (EPS) prodotto da un ceppo di Bifidobacterium longum .
Gli studi sul profilo metabolico dei ceppi isolati, eseguiti utilizzando sistemi standardizzati, confermavano soltanto per 10 ceppi la probabile appartenenza al genere Bifidobacterium spp.
I ceppi caratterizzati come probabili bifidobatteri erano saggiati per la capacità di resistere alle condizioni gastrointestinali e mostravano resistenza a pH 3 e alle differenti concentrazioni di sali biliari saggiate.
Inoltre, i 10 ceppi esaminati per la loro sensibilità agli antibiotici mostravano delle MIC compatibili con i valori di cut-off riportati dall EFSA (2012) per il genere Bifidobacterium spp.
I probabili bifidobatteri e i ceppi probiotici di Bifidobacterium spp. venivano studiati per la loro capacità di adesione, utilizzando le cellule HT-29, mediante metodo quantitativo colturale e osservazione mediante microscopio ottico ad immersione. I risultati mostravano differenti caratteristiche di adesione in relazione al ceppo saggiato, ma anche in relazione al tempo di incubazione. La capacità di adesione del ceppo Bifidobacterium longum W11 veniva ulteriormente indagata mediante microscopia elettronica a scansione che evidenziava la presenza di biopolimeri di probabile natura esopolisaccaridica, organizzati in una complessa struttura 3D e coinvolti nell adesione del ceppo.
Le successive fasi della ricerca erano, quindi, focalizzate sullo studio approfondito di questo biopolimero di natura esopolisaccaridica.
Dopo l estrazione, purificazione e idrolisi, utilizzando anche metodiche messe a punto da noi, l esopolisaccaride (EPS) veniva analizzato per la composizione chimica, mediante TLC, utilizzando piastre in silice e in cellulosa. Entrambi i tipi di piastre permettevano di identificare la presenza di glucosio e galattosio, che veniva confermata con una più accurata analisi cromatografica effettuata mediante HPLC.
La ricerca dei determinanti genetici responsabili della sintesi dell EPS del ceppo B. longum W11 era effettuata mediante PCR e analisi bioinformatica dell intero genoma. I risultati ottenuti mostravano la presenza del gene cpsD , che codifica per la galactosil-transferasi e un cluster genico composto da 23 geni, (24,7 kb).
L attività citotossica veniva saggiata in vitro su fibroblasti gengivali HF1 e tumorali Caco-2. Il saggio su fibroblasti non evidenziava alcun effetto citotossico, mentre quello su cellule tumorali Caco-2 mostrava una modesta diminuzione della vitalità cellulare sin dalla più bassa concentrazione saggiata. Tale decremento, tuttavia non era statisticamente significativo. L eventuale attività immunomodulante dell EPS era analizzata attraverso lo studio del pattern di citochine quali IL-1, IL-6, IL-10 e IFN-gamma, prodotte da cellule immunitarie isolate da PBMC di donatori volontari. I risultati hanno dimostrato per l EPS in esame un effetto di tipo immunomodulante. Inoltre, quando l EPS veniva saggiato in combinazione con ConA si evidenziava un incremento significativo dei livelli di IL-1, IL-6 e IFN-gamma e la riduzione significativa dei livelli di IL-10.
I risultati della ricerca forniscono una buona base sperimentale per ulteriori indagini su altri aspetti non ancora investigati degli EPS ed in particolare dell EPS del ceppo B. longum W11, quali l effetto protettivo sul ceppo produttore dalle condizioni intestinali avverse e/o dall attività inibente degli antibiotici o altre eventuali proprietà biologiche.
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Gorse, Christophe. "Etude expérimentale des translocations bactériennes lors d'aplasies médullaires : rôle de Saccharomyces boulardii et de Bifidobacterium". Montpellier 1, 1992. http://www.theses.fr/1992MON11037.
Testo completo
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Mullié-Demailly, Catherine. "Contribution a l'etude de l'innocuite et de la specificite d'action de bifidobacterium breve c50 et de ses produits de fermentation (doctorat : microbiologie)". Lille 2, 1999. http://www.theses.fr/1999LIL2P253.
Testo completo
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Khattabi, Abdelkrim. "Contribution a la classification et a l'ecologie de souches d'origine humaine appartenant au genre bifidobacterium : mise au point d'un systeme d'identification numerique". Lille 2, 1993. http://www.theses.fr/1993LIL2P253.
Testo completo
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Ravenscroft, John Elmer. "Evaluation of survival and recovery characteristics of bifidobacteria as indicators of fecal pollution of water". Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1613.
Testo completoAbstract (sommario):
Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains xi, 138 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 133-137).