Página 1 dos resultados de 8163 itens digitais encontrados em 0.015 segundos

Immunogenicity of 23-valent pneumococcal polysaccharide vaccine in HIV-infected pregnant women and kinetics of passively acquired antibodies in young infants

ALMEIDA, Volia De Carvalho; MUSSI-PINHATA, Marisa Marcia; SOUZA, Cleonice Barbosa Sandoval De; KUBO, Christina Arslanian; MARTINEZ, Edson Zangiacomi; CARNEIRO-SAMPAIO, Magda Maria; DUARTE, Geraldo
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.66%
Whether gestational immunization of HIV-infected mothers with the 23-valent pneumococcal polysaccharide vaccine (PPV) confers maternal and infant early life, passive protection is not known. We evaluated safety, immunogenicity and placental transfer of antibodies in 44 HIV-infected women. Pneumococcal IgG antibodies against serotypes 1, 3, 5, 613, 9V, and 14 were measured in mothers (pre-vaccination and at delivery), and infants (at birth, 1, 2, 3, and 6 months). PPV was safe and immunogenic in mothers. Newborns received 46-72% of maternal antibody titers. Overall, infants had antibody levels lower than protective by 2 months of age. Alternative pneumococcal vaccination of HIV-infected pregnant women should be explored with the aim of prolonging passive protection in their infants. (C) 2009 Elsevier Ltd. All rights reserved.; Fundacao de Amparo A Pesquisa do Estado de Sao Paulo (FAPESP), Brazil[02/01294-3]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Brazil[302759/2002]

Pneumococcal Nasopharyngeal Carriage Among Infants Born to Human Immunodeficiency Virus-infected Mothers Immunized With Pneumococcal Polysaccharide Vaccine During Gestation

ALMEIDA, Volia de Carvalho; NEGRINI, Bento V. M.; CERVI, Maria C.; ISAAC, Marcia de L.; MUSSI-PINHATA, Marisa M.
Fonte: LIPPINCOTT WILLIAMS & WILKINS Publicador: LIPPINCOTT WILLIAMS & WILKINS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.54%
Background: We have previously shown that 23-valent pneumococcal polysaccharide vaccine (PPV) is immunogenic in human immunodeficiency virus (HIV)-infected mothers and provides vaccine-induced antibodies to the infant. We compared the nasopharyngeal pneumococcal colonization (NPC) rates in <6-month-old infants born to HIV-infected mothers, according to immunization with PPV during pregnancy. Methods: NPC was evaluated in 45 term infants born to vaccinated women (PPV+) and in 60 infants in a control group (PPV-), at 2 months (+/- 30 days), 4 months (+/- 30 days), and 6 months (+/- 30 days) of age. Results: A total of 82 infants completed the study (at least 2 of 3 evaluations), 35 (77%) in the PPV+ and 47 (78.3%) in the PPV- groups, respectively. Infant gender, HIV infection status, number of adults, children, and smokers in the household, day-care attendance, occurrence of respiratory signs, and cotrimoxazole use were similar in both groups. NPC rates increased equally with age in both groups (2 months = 26.7% vs. 25.6%; 4 months = 34.5% vs. 38.6%; 6 months = 38.7% vs. 56.3%, in PPV+ and PPV-, respectively). After controlling for potential confounders, we found no association between maternal vaccination and infant pneumococcal carriage (adjusted odds ratio = 0.70; 95% confidence interval: 0.23...

Interaction of polysaccharide-protein complex from Agaricus blazei with Langmuir and Langmuir-Blodgett films of phospholipids

SCHMIDT, Thais F.; PAVINATTO, Felippe José; CASELI, Luciano; GONZAGA, Maria L. C.; SOARES, Sandra A.; RICARDO, Nagila M. P. S.; OLIVEIRA JUNIOR, Osvaldo Novais de
Fonte: ACADEMIC PRESS INC ELSEVIER SCIENCE Publicador: ACADEMIC PRESS INC ELSEVIER SCIENCE
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.54%
The use of natural substances in health applications may be hampered by the difficulties in establishing the mechanisms of action, especially at molecular-level. The protein-polysaccharide complex extracted from the mushroom Agaricus blazei Murill, referred to as CAb, has been considered for treating various diseases with probable interaction with cell membranes. In this study, we investigate the interaction between CAb and a cell membrane model represented by a Langmuir monolayer of dimyristoyl phosphatidic acid (DMPA). CAb affects the structural properties of DMPA monolayers causing expansion and increasing compressibility. In addition, interaction with DMPA polar heads led to neutralization of the electrical double layer, yielding a zero surface potential at large areas per molecule. CAb remained at the interface even at high surface pressures, which allowed transfer of Langmuir-Blodgett (LB) films onto solid supports with the CAb-DMPA mixture. The mass transferred, according to quartz crystal microbalance (QCM) measurements, increased linearly with the number of deposited layers. With UV-vis absorption, fluorescence and FTIR spectroscopies, we confirmed that the LB films contain polysaccharides, proteins and DMPA. Therefore, the CAb biological action must be attributed not only to polysaccharides but also to proteins in the complex. (C) 2008 Elsevier Inc. All rights reserved.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); FAPESR IMMP; FINED; FINED; CNPq; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Rede Biomat (Brazil); Rede Biomat (Brazil)

Desenvolvimento de processo para obtenção do método de conjugação do polissacarídeo capsular de Haemophilus influenzae tipo b com toxóide tetânico.; Development of process for the conjugation of capsular polysaccharide Haemophilus influenzae type b with tetanus toxoid.

Lorthiois, Ana Paula de Almeida Aranha
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 18/02/2008 PT
Relevância na Pesquisa
36.66%
Haemophilus influenzae type b (Hib) é uma importante bactéria Gram-negativa causadora de pneumonia, meningite e septicemia em crianças abaixo dos 5 anos de idade. A prevenção contra a doença pode ser alcançada pela imunização da população com vacina conjugada polissacarídeo-proteína, uma vez que a vacina de polissacarídeo não é eficiente. As vacinas conjugadas disponíveis comercialmente custam para o governo brasileiro cerca de US2,7 a dose, sendo necessárias no mínimo 3 doses para imunização completa. O presente estudo desenvolveu um novo método de conjugação de polissacarídeo capsular de Hib (PRP) com toxóide tetânico (TT). O método hidrazona baseia-se em 3 etapas simples: oxidação e derivatização de PRP com espaçador molecular e conjugação com TT na presença de uma carbodiimida e de um éster amino reativo. Após um estudo detalhado de cada etapa do método hidrazona, o novo processo mostrou excelentes resultados de rendimento mesmo após escalonamento. A imunogenicidade e o índice de avidez do conjugado hidrazona foram avaliados e os resultados encontrados foram comparáveis a vacina comercial Hiberix®. A técnica de HPSEC mostrou-se eficaz e o perfil cromatográfico do conjugado hidrazona foi muito similar ao da vacina Hiberix. Finalmente...

Otimização da produção de polissacarídeo capsular do Streptococcus pneumoniae sorotipo 6B em biorreator; Optimization of polysaccharide production of Streptococcus pneumoniae serotype 6B in bioreactor

Carmo, Talita Souza
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 31/03/2010 PT
Relevância na Pesquisa
36.66%
O Streptococcus pneumoniae, também conhecido como pneumococo, é um importante agente etiológico causador de pneumonia, bacteremia, meningite e otite aguda do ouvido médio, acometendo especialmente crianças e idosos. A cápsula polissacarídica (PS) é o fator de virulência mais importante e localiza-se na superfície do microrganismo e tem ação anti-fagocítica in vivo. O pneumococo expressa pelo menos 91 cápsulas diferentes, que são química e sorologicamente distintas. Usualmente, a cápsula é o antígeno das vacinas anti-pneumocócicas, tanto como polissacarídeo livre ou conjugado a proteínas. O sorotipo 6B acomete principalmente crianças e é o segundo mais prevalente no Brasil, e a otimização das condições de cultivo buscando maior produtividade em PS é o alvo desta tese. Simultaneamente, também foi investigada a influência do inóculo e da glicose residual no instante do pulso ou do início da alimentação em cultivos descontínuos alimentados. Nos cultivos descontínuos alimentados foi observado que quanto menor a densidade óptica da cultura do inóculo, maior a concentração de PS obtida. A concentração da glicose residual no momento do pulso provavelmente influenciou a produção de PS: a produção foi maior quando o pulso foi dado ainda em altas concentrações de substrato. Por isso...

Desenvolvimento e avaliação da resposta imune humoral de uma vacina anti-pneumocócica conjugada: polissacarídeo capsular sorotipo 14 - proteína de superfície pneumocócica A.; Development and evaluation of the humoral immune response of na antipneumococcal conjugate vaccine: capsular polysaccharide serotype 14-pneumococcal surface protein A.

Santamaria, Raquel
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/03/2011 PT
Relevância na Pesquisa
36.66%
Streptococcus pneumoniae é uma bactéria encapsulada que coloniza a nasofaringe, sendo uma das principais causas de morte por pneumonia e meningite em crianças e idosos. As vacinas contra S. pneumoniae são compostas por polissacarídeos capsulares (PS) livres ou conjugados à uma proteína. A vantagem do polissacarídeo conjugado em relação ao livre é a resposta timo-dependente. Pelo fato de existirem pelo menos 92 diferentes sorotipos capsulares, a utilização de uma proteína pneumocócica em uma vacina conjugada com apenas alguns sorotipos poderia aumentar a sua cobertura vacinal. Para tal, a utilização da proteína de superfície pneumocócica A (PspA) foi utilizada como carreador protéico covalentemente ligado ao polissacarídeo capsular sorotipo 14. Este trabalho também apresenta uma nova metodologia para a síntese de vacinas conjugadas, que vem demonstrando melhores resultados em nosso laboratório em comparação aos métodos clássicos de conjugação. O conjugado PS14-PspA foi administrado em camundongos BALB/c e o título de IgG anti-PS14 e anti-PspA, o índice de avidez, a deposição de complemento e a distribuição das subclasses de IgG foram avaliados. O título de IgG anti-PS14 conjugado foi significativamente maior do que título de IgG anti-PS14 livre. A avidez e a deposição de complemento do soro anti-PS14 conjugado também foram maiores. A principal subclasse de IgG induzida pelo PS14 livre foi IgG3 enquanto o PS14 conjugado induziu preferencialmente IgG1. No entanto...

Polissacarídeo sorotipo 6B de Streptococcus pneumoniae (PS6B) e proteína de superfície pneumocócica A (PspA): métodos de conjugação e avaliação da reposta imune.; Polysaccharide serotype 6B of Streptococcus pneumoniae (PS6B) and pneumococcal surface protein A (PspA): conjugation methods and immune response evaluation.

Perciani, Cátia Taniela
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 12/05/2011 PT
Relevância na Pesquisa
36.74%
Streptococcus pneumoniae é a maior causa de doenças infecciosas invasivas. As vacinas conjugadas, ao contrário das vacinas polissacarídicas, se mostram eficazes na indução de uma resposta protetora em crianças menores de 2 anos de idade. Entretanto, apesar do sucesso na redução dos casos de doenças pneumocócicas, publicações recentes têm mostrado um aumento nos casos de doença por sorotipos de S. pneumoniae não inclusos nas vacinas conjugadas atualmente licenciadas. Com o objetivo de evitar a substituição dos sorotipos prevalentes e aumentar a cobertura vacinal, nosso projeto prevê a introdução de uma proteína de superfície do pneumococo como carreador em uma vacina conjugada. A Proteína de Superfície Pneumocócica A (PspA), por ser conservada entre diversos sorotipos e por sua alta imunogenicidade, foi escolhida para constituir o conjugado, juntamente com o Polissacarídeo Capsular de S. pneumoniae sorotipo 6B (PS6B), um sorotipo de elevada prevalência no Brasil. Também foi avaliada a influência de diferentes espaçadores entre a proteína carreadora e o PS sobre a resposta imune induzida. Estudos envolvendo diferentes condições reacionais tiveram como objetivo o estabelecimento de um protocolo de conjugação com elevado rendimento. A substituição do ativador EDAC (hidrocloreto de 1-[3-(dimetilamino)propil]-3-etilcarbodiimida)...

Effect of glycerol and corn oil on physicochemical properties of polysaccharide films : a comparative study

Cerqueira, M. A.; Souza, B. W. S.; Teixeira, J. A.; Vicente, A. A.
Fonte: Elsevier BV Publicador: Elsevier BV
Tipo: Artigo de Revista Científica
Publicado em //2012 ENG
Relevância na Pesquisa
36.66%
The aim of this work was to evaluate the influence of glycerol and corn oil on physicochemical properties of polysaccharide-based films. The polysaccharides used were galactomannan from Gleditsia triacanthos and chitosan. Fourier-transform infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis were performed, together with determinations of moisture content, solubility, water vapor permeability and mechanical properties. Structure–properties relationships were established, relating the two polysaccharides’ structures with the way they interact with water, other film’s constituents (glycerol and oil) and the resulting properties. The presence of glycerol and corn oil originated a more hydrophilic structure and a decreased affinity of the film matrix to water, respectively, in both polysaccharides. However, the two polysaccharides presented different behaviors in terms of glass transition temperature, water vapor permeability and elongation-at-break that have been related with the particularities of their structure: while for the galactomannan the specific sorption sites for water are the O–H groups, for chitosan those are O–H and/or NH2 groups. The present work provides insight regarding the physicochemical properties of polysaccharide-based films and established relationships with polymers’ structure...

Weak-gel formation in dispersions of silica particles in a matrix of a non-ionic polysaccharide: structure and rheological characterization

Oliveira, Fabiane; Monteiro, Sónia R.; Barros-Timmons, Ana; Lopes-da-Silva, J. A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.74%
Oscillatory and steady shear rheological methods as well as scanning electron microscopy were used to characterize silica(SiO2)/galactomannan dispersions. Particle loading and surface charge are found to strongly influence the composite structure and dynamics. When the particles were added above a minimum concentration, a sol-gel transition was induced. The SiO2/polysaccharide dispersions exhibited significant non-linearities, especially under ionic conditions that favor interparticle and particle-polysaccharide interactions, characterized by strong shear-thinning, diverging viscosities at low shear rates, apparent yield stress and high strain sensitivity. The mechanical spectra for the composite systems suggest that stress relaxation of these composites is effectively arrested by the presence of silica nanoparticles. Microstructural analysis revealed an ordering of the silica particles around the polymer chains. Polysaccharide chains act as templates for particle clustering leading to the formation of a particle-mediated transient biopolymer network, with particle clusters hindering polymer mobility and enhancing junction zones within the network.

Histoplasmin reaction. Comparison of a polysaccharide antigen to the filtrate antigen

FAVA,Sérgio Di Camilo; RIVITTI,Evandro A.; CUCÉ,Luiz Carlos; WEISS,Simone; RIGONE,Gianine; FAVA-NETTO,Celeste
Fonte: Instituto de Medicina Tropical Publicador: Instituto de Medicina Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/1997 EN
Relevância na Pesquisa
36.74%
This work was planned by taking into account all the knowledge accumulated from the immunological study of paracoccidioidomycosis. It aimed at comparing a polysaccharide antigen from Histoplasma capsulatum to a classic histoplasmin with the help of intradermal tests of delayed type of hypersensitivity. Tests were applied to 115 individuals in Santo Amaro, a town in the state of São Paulo. Positive results using classic histoplasmin were obtained in 46.0% cases whereas positive results using the polysaccharide antigen at its hightest concentration were obtained in 51.30% cases. The major conclusion in this investigation is that it is possible to use the polysaccharide antigen as histoplasmin instead of the filtrate antigen

Immunogenicity of a 23-valent pneumococcal polysaccharide vaccine in Brazilian elderly

Simonsen,V.; Brandão,A.P.; Brandileone,M.C.C.; Yara,T.I.; Di Fabio,J.L.; Lopes,M.H.; Jacob Filho,W.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2005 EN
Relevância na Pesquisa
36.74%
Serum antibodies specific for the capsular polysaccharides of Streptococcus pneumoniae provide protection against invasive pneumococcal infection. In Brazil, this vaccine has been used for people over 65 years with clinical risk to develop pneumococcal infection since 1999. We evaluated the immune response of 102 elderly subjects (75.5% females and 24.5% males) with a mean age of 71 years, and 19 young healthy adults (63.2% females and 36.8% males) with a mean age of 27 years. The elderly study group consisted of outpatients who received follow-up care in the Geriatric Department of General Hospital, Faculty of Medicine, University of São Paulo. None had acute illness at the time of vaccination. Both groups were immunized with one intra-deltoid injection with 0.5 ml of a 23-valent pneumococcal polysaccharide vaccine. The total IgG specific antibody concentrations to capsular polysaccharides 1, 3, 5, 6B, 8, and 14 were determined against pre- and 1-month post-vaccination sera. All samples were analyzed according to the second-generation pneumococcal polysaccharide ELISA protocol. We observed that the pneumococcal polysaccharide vaccine evoked consistent antibody increase for serotypes 1, 5, 6B, 8, and 14 (geometric mean concentration increase of 2.46 in the elderly and 2.84 in the young adults). Otherwise...

Antibody response to pneumococcal capsular polysaccharide vaccine in Down syndrome patients

Costa-Carvalho,B.T.; Martinez,R.M.A.; Dias,A.T.N.; Kubo,C.A.; Barros-Nunes,P.; Leiva,L.; Solé,D.; Carneiro-Sampaio,M.M.S.; Naspitz,C.K.; Sorensen,R.U.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2006 EN
Relevância na Pesquisa
36.66%
The majority of children with Down syndrome (DS) tend to have frequent bacterial infections including recurrent respiratory infections. Our objective was to evaluate the production of antibodies to pneumococcal polysaccharide antigens after active immunization in DS subjects. IgG antibodies to pneumococcal serotypes (1, 3, 6B, 9V, and 14) were measured before and 6 weeks after immunization with a 23-valent pneumococcal vaccine (Pneumo23®, Pasteur-Merrieux) in 6- to 13-year-old DS children (N = 17) and in aged-matched normal controls (N = 30). An adequate response was defined as a 4-fold increase over baseline or a post-immunization level of specific pneumococcal serotype antibody > or = 1.3 µg/mL. After immunization, all DS children had an increase in post-immunization levels against all serotypes analyzed. A 4-fold or more increase was observed in all DS children concerning serotypes 1 and 14, in 90% of subjects for serotypes 3 and 9V, and in 65% for serotype 6B. Regarding this increase, 8 of the 17 DS children had an adequate response to all serotypes analyzed, 8/17 patients to 4 serotypes and 1/17 to 3 serotypes. However, when we compared post-immunization levels between DS children and controls, we observed lower levels in the former group (P < 0.05) for all serotypes except serotype 3. We conclude that pneumococcal polysaccharide immunization could be beneficial for these DS children.

Role of the NO/K ATP pathway in the protective effect of a sulfated-polysaccharide fraction from the algae Hypnea musciformis against ethanol-induced gastric damage in mice

Damasceno,Samara R. B.; Rodrigues,Jocélia C.; Silva,Renan O.; Nicolau,Lucas A. D.; Chaves,Luciano S.; Freitas,Ana L. P.; Souza,Marcellus H. L. P.; Barbosa,André L. R.; Medeiros,Jand-Venes R.
Fonte: Sociedade Brasileira de Farmacognosia Publicador: Sociedade Brasileira de Farmacognosia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2013 EN
Relevância na Pesquisa
36.88%
Seaweeds are the most abundant source of polysaccharides such as alginates and agar, as well as carrageenans. This study aimed to investigate the gastroprotective activity and the mechanism underlying this activity of a sulfated-polysaccharide fraction extracted from the algae Hypnea musciformis (Wulfen) J.V. Lamour. (Gigartinales-Rhodophyta). Mice were treated with sulfated-polysaccharide fraction (3, 10, 30, and 90 mg/kg, p.o.) and, after 30 min, they were administered 50% ethanol (0.5 mL/25 g, p.o.). After 1 h, gastric damage was measured using a planimeter. In addition, samples of the stomach tissue were obtained for histopathological examination and for assays to determine the glutathione and malondialdehyde levels. Other groups of mice were pretreated with N G-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg, i.p.), aminoguanidine (100 mg/kg, i.p.), or glibenclamide (10 mg/kg, i.p.). After 30 min to the aminoguanidine group and 1 h to the other groups, sulfated-polysaccharide fraction (30 mg/kg, p.o.) was administered and gastric damage was induced as described above. Sulfated-polysaccharide fraction prevented ethanol-induced gastric injury in a dose-dependent manner. However, treatment with L-NAME or glibenclamide reversed this gastroprotective effect. Administration of aminoguanidine did not influence the effect of sulfated-polysaccharide fraction. Our results suggest that sulfated-polysaccharide fraction exerts a protective effect against ethanol-induced gastric damage via activation of the NO/K ATP pathway.

Enantiomeric Resolution of Drugs and Metabolites in Polysaccharide- and Protein-Based Chiral Stationary Phases

Bonato,Pierina S.; Bortocan,Renato; Gaitani,Cristiane M.; Paias,Fernanda O.; Iha,Maria H.; Lima,Rodrigo P.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2002 EN
Relevância na Pesquisa
36.74%
Several chiral stationary phases based on polysaccharide derivatives and proteins were evaluated for the resolution of some chiral drugs and their metabolites. The polysaccharide-based stationary phases CHIRALCEL OD-H, CHIRALCEL OB-H, CHIRALCEL OJ, CHIRALPAK AD and CHIRALPAK AS were evaluated under normal phase conditions, using hexane:2-propanol or hexane:ethanol as mobile phase. Diethylamine and trifluoracetic acid were also added to improve peak shape. The CHIRALCEL OJ-R, CHIRALCEL OD-R and CHIRALCEL OD-H columns were evaluated under reversed-phase conditions, using acetonitrile:H2O or acetonitrile:NaClO4 solution. The protein- based stationary phases, CHIRAL AGP and ULTRON ES-OVM columns were used with mobile phases consisting of a buffer solution supplemented with an organic modifier. Among the polysaccharide-based stationary phases, CHIRALPAK AD provided better resolution for almost all drugs and metabolites studied. The ULTRON ES-OVM column was particularly suitable for the resolution of the four enantiomers of thioridazine-2-sulfoxide.

Mathematical modeling of capsular polysaccharide production by Neisseria meningitidis serogroup C in bioreactors

Henriques,A. W. S.; Jessouroun,E.; Lima,E. L.; Alves,T. L. M.
Fonte: Brazilian Society of Chemical Engineering Publicador: Brazilian Society of Chemical Engineering
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2005 EN
Relevância na Pesquisa
36.74%
In this work, the process of capsular polysaccharide production by Neisseria meningitidis serogroup C was studied. Batch experimental runs were conducted in a set of one-liter bioreactors with 0.5 L of Frantz cultivation medium. Cultivation temperature and pH were controlled at optimal pre-established values. The dynamic behavior of the bacteria was analyzed based on biomass growth, glucose uptake, polysaccharide production and dissolved oxygen time profile obtained in a set of experimental runs with initial concentrations of glucose that varied from 5 to 13.5 g/L. Formulated hypotheses were then employed in the construction of a phenomenological model of the bioprocess under study that successfully described the dynamic behavior of the system and can be used in future control and optimization of the industrial process of capsular polysaccharide production.

Polysaccharide production in batch process of Neisseria meningitidis serogroup C comparing Frantz, modified Frantz and Cartlin 6 cultivation media

Paz,Marcelo Fossa da; Baruque-Ramos,Júlia; Hiss,Haroldo; Vicentin,Márcio Alberto; Leal,Maria Betania Batista; Raw,Isaías
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2003 EN
Relevância na Pesquisa
36.88%
Polysaccharide of N. meningitidis serogroup C constitutes the antigen for the vaccine against meningitis. The goal of this work was to compare three cultivation media for production of this polysaccharide: Frantz, modified Frantz medium (with replacement of glucose by glycerol), and Catlin 6 (a synthetic medium with glucose). The comparative criteria were based on the final polysaccharide concentrations and the yield coefficient cell/polysaccharide (Y P/X). The kinetic parameters: pH, substrate consumption and cell growth were also determined. For this purpose, 9 cultivation runs were carried out in a 80 L New Brunswick bioreactor, under the following conditions: 42 L of culture medium, temperature 35ºC, air flow 5 L/min, agitation frequency 120 rpm and vessel pressure 6 psi, without dissolved oxygen or pH controls. The cultivation runs were divided in three groups, with 3 repetitions each. The cultivation using the Frantz medium presented the best results: average of final polysaccharide concentration = 0.134 g/L and Y P/X=0.121, followed by Catlin 6 medium, with results of 0.095 g/L and 0.067 respectively. Considering the principal advantages in the use of the synthetic medium, i.e. facilitation of a cultivation and purification steps of the polysaccharide production process...

An extracellular sulfated fucose-rich polysaccharide produced by a tropical strain of cryptomonas obovata (cryptophyceae)

Giroldo, Danilo; Vieira, Armando Augusto Henriques
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.88%
A tropical strain of Cryptomonas obovata Skuja, isolated from a shallow oxbow lake, released a sulfated fucoserich polysaccharide. The polysaccharide is composed mainly of fucose (42%), N-acetyl-galactosamine (26%) and rhamnose (15%), with small quantities of glucuronic acid, mannose, galactose, xylose and glucose. Sulfate accounted for 1.7% total polysaccharide. Quantitative release was studied with cells exposed to optimal culture conditions contrasted with high irradiance and nitrate depletion. This latter set of conditions could simulate stress situati ons usually found in the place from which this strain was isolated. The monosaccharide composition of the polysaccharide was evaluated using PAD-HPLC and gas chromatography. The two irradiances tested (165 mol m???2 s???1 and 2000 mol m???2 s???1) had no significant effect on amounts of polysaccharide released by the cells. Differences were observed when the nitrate availability was varied. In the nitrate-depleted situation, extracellular polysaccharide production was 2.5 times higher than replete cells after 6 h at 165 mol m???2 s???1, and 2.25 times higher at 2000 mol m???2 s???1.

Differential immunogenicity of Vibrio cholerae O139 variants expressing different combinations of naturally occurring and atypical forms of the serogroup polysaccharide

Attridge, S.; Wallerstrom, G.; Li, B.; Morona, R.; Holmgren, J.
Fonte: Elsevier Sci Ltd Publicador: Elsevier Sci Ltd
Tipo: Artigo de Revista Científica
Publicado em //2009 EN
Relevância na Pesquisa
36.74%
Field testing of an inactivated bivalent O1/O139 cholera vaccine suggests that Vibrio cholerae O1 is more immunogenic than V. cholerae O139. To investigate whether this might be partly attributable to the production of capsular polysaccharide (CPS) by O139 isolates, we have compared the immunogenicity of variant strains expressing different combinations of lipopolysaccharide (LPS) and CPS. These studies indicate that the core-linked LPS structure is of paramount importance for induction of antibodies to the serogroup antigen. By contrast CPS was minimally immunogenic. Significantly the presence of CPS did not modulate the immunogenicity of the underlying LPS. To examine whether differences in LPS structure might contribute to the differing immunogenicities of the O1 and O139 serogroups, an attempt was made to modify the normal O139 LPS structure by provision of one of several heterologous wzz genes. The resulting variants displayed additional, atypical surface polysaccharide, whose modal length was characteristic for the particular wzz gene. By immunoblotting this novel material showed a ladder-like banding pattern typical of LPS, but its failure to be stained by silver indicated that it was not core-associated and was therefore more like truncated CPS. Consistent with our earlier findings...

The role of CpsC in the regulation of Streptococcus pneumoniae capsular polysaccharide biosynthesis.

Byrne, James
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2012
Relevância na Pesquisa
36.74%
Streptococcus pneumoniae is the leading cause of pneumonia, bacteraemia (sepsis), meningitis and otitis media worldwide. It is also responsible for more deaths worldwide than any other single pathogen. A major component of pneumococcal virulence is determined by the composition of polysaccharide layer that covers the bacteria, its capsule. The composition of the pneumococcal capsule provides the basis for the classification of the pneumococcus and to date 91 structurally distinct capsular serotypes have been identified. The capsule is essential for the virulence of the pneumococcus and its primary role during pathogenesis is to act as a physical barrier preventing the interaction of cell wall bound opsonins and their cognate receptors on phagocytes, thereby preventing phagocytosis. However, during colonisation, the CPS masks adhesions suggesting the amount of CP expressed on the cell surface needs to be carefully regulated. The regulation of capsule biosynthesis is mediated by the actions of four gene products, CpsA, B, C and D. CpsB, C and D form a series of complex interactions involved in the control of capsule subunit export and chain length regulation while CpsA has recently implicated in the ligation of capsular polysaccharide to the cell wall. A transphosphorylative event at the C-­terminus of CpsD (facilitated by the presence of CpsC) results in a conformational change promoting the ligation of exported capsule subunits to the cell wall via an unknown mechanism. CpsB the de-phoshorylates CpsD resulting in a conformational change conducive to capsule export and polymerization. CpsC has been shown to be essential for the activity of CpsD. The interactions CpsC forms with other proteins involved in capsule biosynthesis have not been fully characterized and this study sought to analyse CpsC function by performing site directed mutagenesis on cpsC and analysing phenotypic changes. Characterisation of these changes and further analysis was used to attempt to determine the structure and oligomeric nature of CpsC under native membrane conditions. Attempts to use computer modelling techniques to better resolve the structure and oligomeric state of CpsC were also made. We have shown that defined single amino acid substitutions in different regions of CpsC can alter the phenotype of D39 to either mucoid or small colony phenotypes. In particular we have highlighted several domains including a region preceding and within the second transmembrane region of Cps2C that...

Desenvolvimento de um método de conjugação entre o polissacarídeo capsular sorotipo 1 de Streptococcus pneumoniae e a proteína de superfície pneumocócica A.; Development of a conjugation method between the capsular polysaccharide serotype 1 of Streptococcus pneumoniae and pneumococcal surface protein A.

Machado, Luciene Oliveira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 23/06/2015 PT
Relevância na Pesquisa
36.66%
Streptococcus pneumoniae é uma bactéria encapsulada causadora de doenças infecciosas como pneumonia, bacteremia e meningite, infecções essas que estão entre as principais causas de morte entre crianças, idosos e imunodeprimidos, indivíduos que constituem o grupo de risco para tais infecções. A vacinação tem sido a mais eficaz forma de conter tais infecções. A vantagem das vacinas conjugadas em comparação às polissacarídicas é a capacidade de indução de uma resposta imune T-dependente o que garante proteção mesmo ao grupo de risco para infecções por S. pneumonia. A proposta do projeto foi estabelecer um protocolo para obtenção de um conjugado constituído pelo polissacarídeo capsular de S. pneumonia sorotipo 1 (PS1) e pela proteína de superfície pneumocócica A (PspA). A síntese do conjugado empregou uma metodologia inédita para o sorotipo 1. A avaliação da resposta imune humoral induzida pelo conjugado mostrou a indução de IgG anti-PS1 gerada pelas imunizações com o conjugado PS1-PspA.; Streptococcus pneumoniae is an encapsulated bacteria causing infectious diseases such as pneumonia, bacteremia and meningitis, these infections are among the leading causes of death among children, elderly and immunocompromised...