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Separation of human immunoglobulin G subclasses on a protein A monolith column

Leblebici, P.; Leblebici, M.E.; Ferreira-da-Silva, F.; Rodrigues, A.E.; Pais, L.S.
Fonte: Instituto Politécnico de Bragança Publicador: Instituto Politécnico de Bragança
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
75.26%
Monolithic columns have attracted significant attention for the purification of large biomolecules. In thepresent study, a step gradient elution method was evaluated for the separation of human immunoglobulinG (hIgG) into its subclasses on CIM (convective interaction media) r-protein A (recombinant protein A)monolithic column. hIgG was loaded onto the column and bound protein was eluted with a pH gra-dient. The subclass content of the eluted fractions was analyzed by enzyme-linked immunosorbentassay (ELISA). Results showed that separation of IgG3 from the other three subclasses can be success-fully achieved with high selectivity (100%) and throughput on monolithic media. It was also revealedthat enriched fractions of IgG1 and IgG2 could be obtained from purified hIgG in a 28 min long chro-matographic run. Three fractions with high IgG1 content (89.1%, 94.3% and 88.8%) were recovered.Furthermore, IgG2 was enriched to 64% successfully. A rapid step gradient elution scheme without anyadditives in buffers was proven to obtain enriched preparations of the two important subclasses withhigh throughput. The separation time can be reduced even more by increasing the flow rate without anyloss in selectivity, which will be beneficial in industrial scale applications.

Avaliação da proteína A do surfactante na síndrome hepatopulmonar em ratos; Evaluation of surfactant protein A in hepatopulmonary syndrome in rats

Nacif, Lucas Souto
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 13/03/2013 Português
Relevância na Pesquisa
65.27%
INTRODUÇÃO: A síndrome hepatopulmonar (SHP) é formada por uma tríade: doença hepática, dilatação vascular intrapulmonar e alteração dos gases no sangue. Sua patogenia não está bem definida, mas especula-se que a combinação de fatores, tais como o desequilíbrio da resposta de receptores da endotelina, a remodelação microvascular pulmonar, a predisposição genética e a translocação de bactérias sejam os desencadeadores das alterações que levarão ao desenvolvimento da síndrome. O pulmão é o local principal de produção do surfactante (células alveolares epiteliais do tipo II) e desempenha um papel importante na lesão e doenças inflamatórias pulmonares. Até o momento não há relatos de avaliação do surfactante na cirrose ou na SHP. OBJETIVO: Avaliar a concentração da proteína A do surfactante na síndrome hepatopulmonar induzida em ratos. MÉTODO: Três grupos de ratos foram divididos em controle, Sham e grupo experimental de SHP. Grupo controle: somente coleta dos exames; grupo Sham: realizada a cirurgia simulada; e o grupo do modelo experimental: indução de cirrose biliar secundária através da ligadura da via biliar principal. Foi realizado a avaliação da proteína A do surfactante no homogenato pulmonar e sérico através do método imunoenzimático ELISA indireto. RESULTADOS: Observou-se depois de 28 dias a evidência de cirrose em todos os ratos operados e a apresentação de SHP em 85% dos ratos. No homogenato do pulmão no grupo LVBP e Sham...

Serological diagnosis of visceral leishmaniasis by an enzyme immunoassay using protein A in naturally infected dogs

Lima, Valéria Marçal Felix de; Biazzono, Luciane; Silva, Ana Cláudia; Correa, Ana Paula Ferreira Lopes; Luvizotto, Maria Cecília Rui
Fonte: Colégio Brasileiro de Patologia Animal - CBPA Publicador: Colégio Brasileiro de Patologia Animal - CBPA
Tipo: Artigo de Revista Científica Formato: 215-218
Português
Relevância na Pesquisa
65.24%
Um ensaio de imunoadsorção enzimática para detecção de anticorpos contra Leishmania chagasi, utilizando antígeno total de formas promastigotas lisados foi desenvolvido. Cinqüenta cães com sintomas clínicos de leishmaniose visceral foram examinados. Esta técnica utilizou anti-IgG de cão conjugado a peroxidase ou proteína A conjugado a peroxidase. Foi verificado que nos animais positivos diagnosticados por exame parasitológico direto o ensaio ELISA utilizando proteína A conjugada a peroxidase (média da densidade óptica ± desvio padrão 2,078 ± 0,631) detecta mais anticorpos do que o sistema utilizando anti-IgG de cão conjugado a peroxidase (média da densidade óptica ± desvio padrão 1,008 ± 0,437), enquanto para os animais negativos o resultado obtido nos dois sistemas de detecção são similares. Esse resultado sugere que o sistema de ELISA utilizando proteína A conjugado a peroxidase pode ser útil na detecção de animais na fase aguda da infecção e desta forma auxiliar na identificação dos animais positivos e no controle desta importante zoonose.; A rapid indirect enzyme-linked immunosorbent assay (ELISA) was developed for measuring antibodies against Leishmania chagasi using total antigen from lysed promastigotes. Fifty symptomatic mixed breed dogs from a region of high incidence of visceral leishmaniasis in Brazil were examined. The results showed that in the positive animals...

DNA and heparin chaperone the refolding of purified recombinant replication protein A subunit 1 from Leishmania amazonensis

Lira, C. B. B.; Gui, K. E.; Perez, A. M.; da Silveira, R. C. V.; Gava, L. M.; Ramos, C. H. I.; Cano, M. I. N.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 119-125
Português
Relevância na Pesquisa
75.3%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 06/58175-7; Replication protein A (RPA) is a single-stranded DNA-binding protein that has been implicated in DNA metabolism and telomere maintenance. Subunit 1 of RPA from Leishmania amazonensis (LaRPA-1) has previously been affinity-purified oil a column containing a G-rich telomeric DNA. LaRPA-1 binds and co-localizes with parasite telomeres in vivo. Here we describe the purification and characterization of native recombinant LaRPA-1 (rLaRPA-1). The protein was initially re-solubilized from inclusion bodies by using urea. After dialysis, rLaRPA-1 was soluble but contaminated with DNA, which was removed by an anion-exchange chromatography of the protein solubilized ill Urea. However, rLaRPA-1 precipitated after dialysis to remove urea. To investigate whether the contaminating DNA was involved in chaperoning the refolding of rLaRPA-1, salmon sperm DNA or heparin was added to the solution before dialysis. The addition of either of these Substances prevented the precipitation of rLaRPA-1. The resulting rLaRPA-1 was soluble, correctly folded, and able to bind telomeric DNA. This is the first report showing the characterization of rLaRPA1 and of the importance of additives in chaperoning the refolding of this protein. The availability of rLaRPA-1 should be helpful in assessing the importance of this protein as a potential drug target. (C) 2008 Elsevier B.V. All rights reserved.

Invasin of Yersinia pseudotuberculosis is not a polyclonal activator of mouse B lymphocytes

De Medeiros, Beatriz Maria Machado; Cangiani, E. E.; Higuti, L.; Satomi, L. C.; Souza, C. D.; Silva, A. R C; Maia, J. M L; Falcão, D. P.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 221-227
Português
Relevância na Pesquisa
65.19%
It is known that the invasin molecule of Yersinia pseudotuberculosis stimulates human peripheral B cells in vitro. In this work we evaluated the in vivo role of invasin as polyclonal activator of B lymphocytes in the mouse experimental model, by comparing strains of Y. pseudotuberculosis expressing invasin and isogenic inv mutants. Swiss mice were infected intravenously with two strains expressing invasin (YpIII pIB1 and an isogenic virulence plasmid-cured strain, YpIII) and with two invasin mutant strains (Yp100 pIB1 and Yp100, plasmid-cured). Spleen cells were sampled on days 7, 14, 21 and 28 after infection. Immunoglobulin (Ig)-secreting spleen cells were detected by protein A plaque assay and specific antibodies were detected in sera by ELISA. The virulent strain YPIII pIB1 (wild type) did not provoke polyclonal activation of B lymphocytes in vivo. In general, fewer Ig-secreting spleen cells of all isotypes were found in the infected animals than in the control animals. Specific IgG antibodies were detected in the sera of animals infected with all strains. The peak response occurred on the 21 st day post-infection, and the Yp100 strain provoked the highest level of these antibodies. We concluded that invasin is not a polyclonal activator of murine B cells.

Serological diagnosis of visceral leishmaniasis by an enzyme immunoassay using protein A in naturally infected dogs

Lima,Valéria Marçal Felix de; Biazzono,Luciane; Silva,Ana Cláudia; Correa,Ana Paula Ferreira Lopes; Luvizotto,Maria Cecília Rui
Fonte: Colégio Brasileiro de Patologia Animal - CBPA; Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Publicador: Colégio Brasileiro de Patologia Animal - CBPA; Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2005 Português
Relevância na Pesquisa
65.25%
A rapid indirect enzyme-linked immunosorbent assay (ELISA) was developed for measuring antibodies against Leishmania chagasi using total antigen from lysed promastigotes. Fifty symptomatic mixed breed dogs from a region of high incidence of visceral leishmaniasis in Brazil were examined. The results showed that in the positive animals, diagnosed by cytological examination, the ELISA using protein A assay system (mean optical density ± SD / 2.078 ± 0.631) detected more antibodies than the anti-IgG assay (mean optical density ± SD / 1.008 ± 0.437), while in the negative animals, the results by both systems were similar. These results suggest that the ELISA assay using protein A peroxidase conjugated could be useful to detect early infected animals in endemic areas, and thus help to control the spread of the infection.

Regulation of protein A synthesis by the sar and agr loci of Staphylococcus aureus.

Cheung, A L; Eberhardt, K; Heinrichs, J H
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1997 Português
Relevância na Pesquisa
55.31%
The synthesis of protein A in Staphylococcus aureus is regulated by global regulatory loci such as sar and agr. Phenotypic data indicate that both sar and agr suppress protein A synthesis; like agr, sar also regulates protein A production at the transcriptional level. To determine the genetic requirement of sar in protein A suppression, we transformed shuttle plasmids containing various sar fragments into a sar mutant. Our results indicated that the 560-bp sarA transcript, or, more probably, the SarA protein (13.5 kDa), is sufficient for suppressing protein A gene transcription when introduced on a multicopy plasmid or as a single copy in the chromosome. Immunoblot analysis with a chicken anti-protein A antibody also confirmed the reduction in protein A expression in these sar mutant clones. Complementation studies revealed that the transcription of the protein A gene can be suppressed in a sar mutant background by a plasmid containing RNAIII. Surprisingly, in agr deletion mutant clones and in clones derived from the agr-sar double mutant, protein A gene transcription can also be suppressed by plasmids containing the sarA transcript plus additional upstream sequence but not the sarA transcript alone. These data suggest that the sar locus can down-modulate protein A gene transcription via both RNAIII-dependent and RNAIII-independent pathways. Consistent with the hypothesis of an RNAIII-independent pathway is an additional genetic requirement for protein A suppression in the agr deletion mutant RN6911 as well as the isogenic double sar-agr mutant...

Human kininogens interact with M protein, a bacterial surface protein and virulence determinant.

Ben Nasr, A B; Herwald, H; Müller-Esterl, W; Björck, L
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/01/1995 Português
Relevância na Pesquisa
55.31%
Streptococcus pyogenes, the most significant streptococcal species in clinical medicine, expresses surface proteins with affinity for several human plasma proteins. Here we report that kininogens, the precursors to the vasoactive kinins, bind to the surface of S. pyogenes. M protein, a surface molecule and a major virulence factor-in these bacteria, occurs in > 80 different serotypes. Among 49 strains of S. pyogenes, all of different M serotypes, 41 bound radiolabelled kininogens, whereas 6 M protein-negative mutant strains showed no affinity. M protein of most serotypes bind fibrinogen, and among the 55 strains tested, binding of kininogens was closely correlated to fibrinogen binding (r = 0.88, P < 0.0001). Western blotting, slot binding and enzyme immunoassay experiments demonstrated that M proteins isolated from S. pyogenes of three different M protein serotypes (M1, M6 and M46) bound kininogens. The affinity between kininogens and M1 protein was determined to be 5 x 10(7) M-1 and < or = 10(6) M-1 for high molecular weight (H-kininogen) and low molecular weight kininogen, respectively. The kininogen binding site was tentatively mapped to the N-terminal portion of M1 protein, and this site does not overlap the specific and separate binding sites for albumin...

The binding of calcium to a salivary phosphoprotein, protein C, and comparison with calcium binding to protein A, a related salivary phosphoprotein.

Bennick, A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/05/1977 Português
Relevância na Pesquisa
55.32%
The binding of Ca2+ to a salivary phosphoprotein, protein C, was studied by equilibrium dialysis. In 5mM-Tris/HCl buffer, pH 7.5, protein C bound 190 nmol of Ca2+/mg of protein. The apparent dissociation constant, K, was determined to be 1.9 x 10(-4)M and the binding of Ca2+ to the protein was non-co-operative. The binding of Ca2+ to protein C apparently depends on groups which ionize above pH 5.0. Ca2+ binding decreased with increased concentration of the dialysis buffer and on addition of SrCL2, MgCl2 and MnCl2 to the dialysis buffer. Digestion of protein C with trypsin or collagenase or heating of the protein to 60 degrees or 100 degrees C had little or no effect on the Ca2+ binding. Digestion of protein C with alkaline phosphatase caused a decrease in the amount of protein-bound Ca2+. This was also found for another salivary phosphoprotein, protein A. In the absence of Ca2+ the S020,w for protein C was 1.29 S and in the presence of Ca2+ it was 1.46S. Ca2+ may cause a conformational change in the protein or an aggregation of the protein molecules. No conformational changes of protein C in the presence of Ca2+ could be detected by circular dichroism or nuclear magnetic resonance.

Crystal structure of the Leishmania major MIX protein: A scaffold protein that mediates protein–protein interactions

Gorman, Michael A; Uboldi, Alex D; Walsh, Peter J; Tan, Kher Shing; Hansen, Guido; Huyton, Trevor; Ji, Hong; Curtis, Joan; Kedzierski, Lukasz; Papenfuss, Anthony T; Dogovski, Con; Perugini, Matthew A; Simpson, Richard J; Handman, Emanuela; Parker, Michael
Fonte: Wiley Subscription Services, Inc., A Wiley Company Publicador: Wiley Subscription Services, Inc., A Wiley Company
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
65.29%
Infection by Leishmania and Trypanosoma causes severe disease and can be fatal. The reduced effectiveness of current treatments is largely due to drug resistance, hence the urgent need to develop new drugs, preferably against novel targets. We have recently identified a mitochondrial membrane-anchored protein, designated MIX, which occurs exclusively in these parasites and is essential for virulence. We have determined the crystal structure of Leishmania major MIX to a resolution of 2.4 Å. MIX forms an all α-helical fold comprising seven α-helices that fold into a single domain. The distribution of helices is similar to a number of scaffold proteins, namely HEAT repeats, 14-3-3, and tetratricopeptide repeat proteins, suggesting that MIX mediates protein–protein interactions. Accordingly, using copurification and mass spectroscopy we were able to identify several proteins that may interact with MIX in vivo. Being parasite specific, MIX is a promising new drug target and, thus, the structure and potential interacting partners provide a basis for structure-guided drug discovery.

High-resolution structure prediction of a circular permutation loop

Correia, Bruno E; Holmes, Margaret A; Huang, Po-Ssu; Strong, Roland K; Schief, William R
Fonte: Wiley Subscription Services, Inc., A Wiley Company Publicador: Wiley Subscription Services, Inc., A Wiley Company
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
65.26%
Methods for rapid and reliable design and structure prediction of linker loops would facilitate a variety of protein engineering applications. Circular permutation, in which the existing termini of a protein are linked by the polypeptide chain and new termini are created, is one such application that has been employed for decreasing proteolytic susceptibility and other functional purposes. The length and sequence of the linker can impact the expression level, solubility, structure and function of the permuted variants. Hence it is desirable to achieve atomic-level accuracy in linker design. Here, we describe the use of RosettaRemodel for design and structure prediction of circular permutation linkers on a model protein. A crystal structure of one of the permuted variants confirmed the accuracy of the computational prediction, where the all-atom rmsd of the linker region was 0.89 Å between the model and the crystal structure. This result suggests that RosettaRemodel may be generally useful for the design and structure prediction of protein loop regions for circular permutations or other structure-function manipulations.

Conservation of surfactant protein a: evidence for a single origin for vertebrate pulmonary surfactant

Sullivan, Lucy C.; Daniels, Christopher Brian; Phillips, Ian D.; Orgeig, Sandra; Whitsett, Jeffrey A.
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Artigo de Revista Científica
Publicado em //1998 Português
Relevância na Pesquisa
75.27%
Surface tension is reduced at the air–liquid interface in the lung by a mixture of lipids and proteins termed pulmonary surfactant. This study is the first to provide evidence for the presence of a surfactant-specific protein (Surfactant Protein A—SP-A) in the gas-holding structures of representatives of all the major vertebrate groups. Western blot analysis demonstrated cross-reactivity between an antihuman SP-A antibody and material lavaged from lungs or swimbladders of members from all vertebrate groups. Immunocytochemistry localized this SP-A–like protein to the air spaces of lungs from the actinopterygiian fish and lungfish. Northern blot analysis indicated that regions of the mouse SP-A cDNA sequence are complementary to lung mRNA from all species examined. The presence of an SP-A–like protein and SP-A mRNA in members of all the major vertebrate groups implies that the surfactant system had a single evolutionary origin in the vertebrates. Moreover, the evolution of the surfactant system must have been a prerequisite for the evolution of airbreathing. The presence of SP-A in the goldfish swimbladder demonstrates a role for the surfactant system in an organ that is no longer used for airbreathing.; Lucy C. Sullivan, Christopher B. Daniels...

Expression, purification and characterization of cold shock protein A of Corynebacterium pseudotuberculosis

Lindae, Antje; Eberle, Raphael J.; Caruso, Icaro P.; Coronado, Monika A.; Moraes, Fabio R. de; Azevedo, Vasco; Arni, Raghuvir K.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 15-20
Português
Relevância na Pesquisa
65.23%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); The gram-positive bacterium Corynebacterium pseudotuberculosis is the causative agent of different diseases that cause dramatically reduced yields of wool and milk, and results in weight loss, carcass condemnation and also death mainly in sheep, equids, cattle and goats and therefore globally results in considerable economical loss. Cold shock proteins are conserved in many bacteria and eukaryotic cells and they help to restore normal cell functions after cold shock in which some appear to have specific functions at normal growth temperature as well.Cold shock protein A from C pseudotuberculosis was expressed in Escherichia coli and purified. The thermal unfolding/refolding process characterized by circular dichroism, differential scanning calorimetry and NMR spectroscopy techniques indicated that the refolding process was almost completely reversible. (C) 2015 Elsevier Inc. All rights reserved.

A comparison of antiserum and protein A as secondary reagents to assess Toxoplasma gondii antibody titers in cats and spotted hyenas

Wait, L.F.; Srour, A.; Smith, I.G.; Cassey, P.; Sims, S.K.; McAllister, M.M.
Fonte: American Society of Parasitologists Publicador: American Society of Parasitologists
Tipo: Artigo de Revista Científica
Publicado em //2015 Português
Relevância na Pesquisa
75.28%
Toxoplasma gondii is a protozoal parasite with worldwide distribution that is able to infect a wide variety of mammals and birds. Our main goal was to screen for T. gondii antibody titers in a previously untested species, the spotted hyena ( Crocuta crocuta); however, this goal first required us to investigate serological procedures that could be suitable for hyenas. Cats are the closest domestic relations of hyenas, so T. gondii antibody titers were first compared in 26 feral cats with specific or nonspecific fluorophore-labeled secondary reagents, i.e., anti-cat IgG or protein A. Substitution of anti-cat IgG with protein A caused a statistically significant drop in titer measurements in cats (P = 0.01) with a reduction of the geometric mean titer equivalent to 1 doubling-dilution. The same procedures were then applied to captive spotted hyenas. Titers measured in 9 of 10 hyenas were identical whether anti-cat IgG or protein A was used as the secondary reagent: 5 had titers <1:16, 2 had titers of 1:16, and 2 had titers of 1:32. One hyena had maximum titers of 1:64 or 1:32 when anti-cat IgG or protein A was used, respectively. The use of protein A as the secondary reagent in serologic assays can be applied to a range of mammalian species and seems unlikely to affect test specificity; however...

The pyruvate kinase model system, a cautionary tale for the use of osmolyte perturbations to support conformational equilibria in allostery

Fenton, Aron W; Johnson, Troy A; Holyoak, Todd
Fonte: Wiley Subscription Services, Inc., A Wiley Company Publicador: Wiley Subscription Services, Inc., A Wiley Company
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
65.25%
In the study of rabbit muscle pyruvate kinase (M1-PYK), proline has previously been used as an osmolyte in an attempt to determine a role for preexisting conformational equilibria in allosteric regulation. In this context, osmolytes are small molecules assumed to have no direct interaction with the protein. In contrast to proline's proposed role as an osmolyte, the structure of M1PYK-Mn-pyruvate-proline complex reported herein demonstrates that proline binds specifically to the allosteric site of M1-PYK. Therefore, this amino acid is an allosteric effector rather than a benign osmolyte. Other compounds often used as osmolytes (polyethyleneglycol and glycerol) are also present in the structure, suggesting an interaction with the protein that would, in turn, prevent the usefulness of these compounds in the study of this and most likely other proteins. These findings highlight the need to verify that compounds used as osmolytes to perturb preexisting conformational equilibrium do not directly interact with the protein, a consideration not commonly addressed in the past.

Surfactant protein A is decreased in the lung of rats with hepatopulmonary syndrome

Nacif,Lucas Souto; Andraus,Wellington; Kubrusly,Márcia Saldanha; Kubrusly,Flávia Saldanha; Gebara,Vera Cristina Bugelli Cainelli; Ishizawa,Andrea; D'Albuquerque,Luiz Augusto Carneiro
Fonte: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia Publicador: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2014 Português
Relevância na Pesquisa
65.27%
PURPOSE: To evaluate surfactant protein A levels in an hepatopulmonary syndrome rat model. To date, there have been no studies aimed at evaluating surfactant levels in the setting of cirrhosis or hepatopulmonary syndrome. METHODS: A total of 35 rats were divided into control, sham, and experimental HPS groups. We evaluated surfactant protein A levels in rats and the experimental model designed to induce hepatopulmonary syndrome was common bile duct ligation. Statistical analysis was performed using GraphPad Prism Software(r). Differences were considered statistically significant when p<0.05. RESULTS: Lung homogenate of surfactant protein A levels were lower in the experimental hepatopulmonary syndrome and sham groups in comparison to the control group (p<0.05). Serum SP-A levels were the same in experimental hepatopulmonary syndrome and control groups but decreased in the sham group compared with the experimental groups (p<0.05). Myeloperoxidase activity was higher in the experimental hepatopulmonary syndrome group than the other two groups (p<0.05). CONCLUSION: Surfactant protein A is present in experimental hepatopulmonary syndrome and leads to an imbalance between serum and pulmonary levels due to systemic inflammatory response.

Detection of adrenocortical autoantibodies in Addison's disease with a peroxidase-labelled protein A technique

Silva,R.C.; Faiçal,S.; Laureti,S.; Falorni,A.; Dib,S.A.; Kater,C.E.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/1998 Português
Relevância na Pesquisa
75.22%
Adrenocortical autoantibodies (ACA), present in 60-80% of patients with idiopathic Addison's disease, are conventionally detected by indirect immunofluorescence (IIF) on frozen sections of adrenal glands. The large-scale use of IIF is limited in part by the need for a fluorescence microscope and the fact that histological sections cannot be stored for long periods of time. To circumvent these restrictions we developed a novel peroxidase-labelled protein A (PLPA) technique for the detection of ACA in patients with Addison's disease and compared the results with those obtained with the classical IIF assay. We studied serum samples from 90 healthy control subjects and 22 patients with Addison's disease, who had been clinically classified into two groups: idiopathic (N = 13) and granulomatous (N = 9). ACA-PLPA were detected in 10/22 (45%) patients: 9/13 (69%) with the idiopathic form and 1/9 (11%) with the granulomatous form, whereas ACA-IIF were detected in 11/22 patients (50%): 10/13 (77%) with the idiopathic form and 1/9 (11%) with the granulomatous form. Twelve of the 13 idiopathic addisonians (92%) were positive for either ACA-PLPA or ACA-IIF, but only 7 were positive by both methods. In contrast, none of 90 healthy subjects was found to be positive for ACA. Thus...

A Naturally Occurring Novel Allele of Escherichia coli Outer Membrane Protein A Reduces Sensitivity to Bacteriophage

Power, Michelle L.; Ferrari, Belinda; Littlefield-Wyer, Jane; Gordon, David; Slade, Martin; Veal, Duncan
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
65.25%
A novel Escherichia coli outer membrane protein A (OmpA) was discovered through a proteomic investigation of cell surface proteins. DNA polymorphisms were localized to regions encoding the protein's surface-exposed loops which are known phage receptor sit

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 Português
Relevância na Pesquisa
65.21%
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...

Comparison of techniques of detecting immunoglobulin-binding protein reactivity to immunoglobulin produced by different avian and mammalian species

Justiz-Vaillant,AA; Akpaka,PE; McFarlane-Anderson,N; Smikle,MF
Fonte: West Indian Medical Journal Publicador: West Indian Medical Journal
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2013 Português
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The rationale of this study was to use several immunological assays to investigate the reactivity of immunoglobulin binding protein (IBP) to immunoglobulins from various avian and mammalian species. The IBP studied were Staphylococcal protein A (SpA), Streptococcal protein G (SpG), Peptostreptococcal protein L (SpL) and recombinant protein LA (SpLA). The various immunological techniques used were double immunodiffusion (Ouchterlony technique) that tested positive high protein reactivities, direct and competitive enzyme-linked immunosorbent assays (ELISAs) that tested moderate and low positive protein binding capacities, respectively. In addition to sandwich ELISAs, immunoblot analyses and Ig-purification by SpA-affinity chromatography, which were sensitive tests and helpful in the screening and confirmatory tests were also used. The Ouchterlony technique showed that compared to the other proteins, SpLA had the highest range of reactivity with animal sera and purified immunoglobulins while SpL was least reactive. With the direct ELISA, SpL reacted with the raccoon sera, rabbit IgG and with IgY from bantam hens and pigeons. While with the direct ELISA, SpA reacted with sera from skunk, coyote, raccoon, mule, donkey and human. The sandwich ELISA revealed high reactivity of both SpG and SpLA with mammalian sera titres ranging from 1:32 (raccoon serum) to 1:1024 (mule and donkey sera).These results suggest that IBP can be used for the detection of immunoglobulin using various immunological assays and this is important for the diagnosis of infectious diseases in animal and bird populations studied and in the purification of immunoglobulins.