Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 18 de 18
Filter
Add more filters










Publication year range
1.
J Dairy Sci ; 103(5): 4588-4605, 2020 May.
Article in English | MEDLINE | ID: mdl-32113759

ABSTRACT

Staphylococcus aureus is one of the pathogens most frequently isolated from cases of mastitis worldwide. To decrease the effect of S. aureus mastitis in dairy farming, alternative strategies for controlling mastitis are needed that depend on a better knowledge of cow-to-cow variations in S. aureus antibody production. The present study sought to explore the diversity of S. aureus antibodies produced by dairy cows with a distinct mastitis history and vaccinated with a polyvalent mastitis vaccine. We obtained protein extracts from S. aureus isolates derived from persistent subclinical mastitis. Proteins were fractionated using 2-dimensional gel electrophoresis and Western blotting. Then, Western blotting membranes were exposed to sera from 24 dairy cows that had been divided into the following groups: vaccinated dairy cows that were infected with S. aureus, further subdivided according to whether they (a) remained infected by S. aureus or (b) recovered from the intramammary infection; unvaccinated dairy cows infected with S. aureus; and vaccinated healthy dairy cows with no history of S. aureus mastitis. Proteins found to be reactive by Western blot were identified by mass spectrometry (MALDI/TOF-TOF). Our most important finding was that F0F1 ATP synthase subunit α, succinyl-diaminopimelate desuccinylase, and cysteinyl-tRNA synthetase were potential candidate proteins for the prevention of S. aureus mastitis. This study strengthens the notion that variations among animals should not be ignored and shows that the heterogeneity of antibody production against anti-staphylococcal antigens in animals may enable the identification of new immunotherapy targets.


Subject(s)
Antibodies, Bacterial/blood , Mastitis, Bovine/immunology , Staphylococcal Infections/veterinary , Staphylococcal Vaccines/administration & dosage , Staphylococcus aureus/immunology , Animals , Antibodies, Bacterial/immunology , Cattle , Female , Humans , Mastitis, Bovine/microbiology , Mastitis, Bovine/prevention & control , Milk , Staphylococcal Infections/immunology , Staphylococcal Infections/microbiology , Staphylococcal Vaccines/immunology
2.
Braz. j. biol ; 80(1): 81-86, Feb. 2020. graf
Article in English | LILACS | ID: biblio-1089303

ABSTRACT

Abstract Wilson's Plover, Charadrius wilsonia, is widely distributed in coastal areas of the Americas. This report presents the first record of breeding in this species on Coroa do Avião Island, on the coast of Pernambuco, and in the estuary of the Cardoso and Camurupim rivers, on the coast of Piauí, in northeastern Brazil, extending the known area of reproduction of this species in this region. One breeding pair was observed on October 29th 2014 on Coroa do Avião Island, and a second pair was recorded on April 6th 2016 in the Cardoso/Camurupim estuary on the Piauí coast. Both the male and the female contributed to the incubation of the eggs. The nest on Coroa do Avião island was camouflaged by the local vegetation, but despite this, the eggs were attacked by a predator. Possible predators observed on the island included Caracara plancus and domestic cats and dogs.


Resumo Charadrius wilsonia (Wilson's Plover) está amplamente distribuído pela costa das Américas. Este é o primeiro registro de reprodução no litoral de Pernambuco, Coroa do Avião, e no estuário dos rios Cardoso e Camurupim, litoral do Piauí, Brasil, ampliando a área de reprodução no Nordeste do Brasil. Foi encontrado um casal em período reprodutivo em 23 de outubro de 2014 na ilha Coroa do Avião, litoral de Pernambuco e outro registro em 06 de abril de 2016 nos estuários Cardoso e Camurupim, litoral do Piauí. Foi observado que o macho e a fêmea contribuem na incubação dos ovos. A vegetação na ilha contribui para a camuflagem do ninho, bem como na proteção dos ovos pelos predadores. Apesar da proteção ocorreu a predação do ninho na ilha Coroa do Avião. Alguns possíveis predadores foram registrados na ilha, como Caracara plancus que diariamente frequentam a área e animais domésticos como cães e gatos.


Subject(s)
Animals , Male , Female , Cats , Dogs , Breeding , Charadriiformes , Reproduction , Brazil
3.
Braz J Biol ; 80(1): 81-86, 2020.
Article in English | MEDLINE | ID: mdl-31017236

ABSTRACT

Wilson's Plover, Charadrius wilsonia, is widely distributed in coastal areas of the Americas. This report presents the first record of breeding in this species on Coroa do Avião Island, on the coast of Pernambuco, and in the estuary of the Cardoso and Camurupim rivers, on the coast of Piauí, in northeastern Brazil, extending the known area of reproduction of this species in this region. One breeding pair was observed on October 29th 2014 on Coroa do Avião Island, and a second pair was recorded on April 6th 2016 in the Cardoso/Camurupim estuary on the Piauí coast. Both the male and the female contributed to the incubation of the eggs. The nest on Coroa do Avião island was camouflaged by the local vegetation, but despite this, the eggs were attacked by a predator. Possible predators observed on the island included Caracara plancus and domestic cats and dogs.


Subject(s)
Breeding , Charadriiformes , Animals , Brazil , Cats , Dogs , Female , Male , Reproduction
4.
Vet J ; 253: 105387, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31685139

ABSTRACT

Diagnosing canine visceral leishmaniasis (CVL) is difficult because clinical signs of the disease are non-specific and a many infected animals in endemic areas, as in Brazil, are asymptomatic. Serological tests are the most common diagnostic methods employed, but most have limitations. For this reason, the implementation of a rapid, sensitive, and specific diagnostic test for CVL has become increasingly important. In this study, we adapted a chemiluminescent enzyme-linked immunosorbent assay (CL ELISA), using two multi-epitope recombinant proteins (PQ10 and PQ20) and a crude Leishmania antigen produced using promastigotes of L. infantum, as antigens to detect CVL infection in animals from Belo Horizonte. To investigate cross-reactions, samples from dogs with other infections (babesiosis, ehrlichiosis and Trypanosoma cruzi) were tested. Assay performance validations were conducted to analyse parameters such as variability, reproducibility, and stability. CL ELISA sensitivity/specificity with PQ10 antigen was 93.1%/80.0%; with the PQ20 protein 93.1%/96.6%; and with the crude antigen 75%/73.3%. Inter-assay variability and inter-operator coefficient of variation were <7% and <15%, with PQ10 and PQ20, respectively. The accuracy of the CL ELISA was classified as excellent for PQ10 (AUC = 0.95) and PQ20 (AUC = 0.98) and moderate for the crude antigen (AUC = 0.77). The kappa score for qualitative agreement between two plate lots was excellent for PQ10 (0.89) and good for PQ20 (0.65). PQ20 remained more stable than PQ10. The CL ELISA with recombinant proteins is a promising tool to diagnose CVL.


Subject(s)
Antibodies, Protozoan/blood , Antigens, Protozoan/immunology , Dog Diseases/diagnosis , Leishmania infantum/immunology , Leishmaniasis, Visceral/veterinary , Animals , Dog Diseases/immunology , Dog Diseases/parasitology , Dogs , Enzyme-Linked Immunosorbent Assay/veterinary , Female , Leishmaniasis, Visceral/blood , Leishmaniasis, Visceral/diagnosis , Luminescent Measurements/veterinary , Male , Sensitivity and Specificity , Serologic Tests/veterinary
5.
Braz J Med Biol Res ; 51(3): e7033, 2018 Jan 11.
Article in English | MEDLINE | ID: mdl-29340527

ABSTRACT

In the present study, we successfully demonstrated for the first time the existence of cardiac proteomic differences between non-selectively bred rats with distinct intrinsic exercise capacities. A proteomic approach based on two-dimensional gel electrophoresis coupled to mass spectrometry was used to study the left ventricle (LV) tissue proteome of rats with distinct intrinsic exercise capacity. Low running performance (LRP) and high running performance (HRP) rats were categorized by a treadmill exercise test, according to distance run to exhaustion. The running capacity of HRPs was 3.5-fold greater than LRPs. Protein profiling revealed 29 differences between HRP and LRP rats (15 proteins were identified). We detected alterations in components involved in metabolism, antioxidant and stress response, microfibrillar and cytoskeletal proteins. Contractile proteins were upregulated in the LVs of HRP rats (α-myosin heavy chain-6, myosin light chain-1 and creatine kinase), whereas the LVs of LRP rats exhibited upregulation in proteins associated with stress response (aldehyde dehydrogenase 2, α-crystallin B chain and HSPß-2). In addition, the cytoskeletal proteins desmin and α-actin were upregulated in LRPs. Taken together, our results suggest that the increased contractile protein levels in HRP rats partly accounted for their improved exercise capacity, and that proteins considered risk factors to the development of cardiovascular disease were expressed in higher amounts in LRP animals.


Subject(s)
Heart Function Tests/methods , Myocardium/metabolism , Physical Conditioning, Animal/physiology , Proteins/metabolism , Running/physiology , Animals , Contractile Proteins/metabolism , Cytoskeletal Proteins/metabolism , Desmin/metabolism , Electrophoresis, Gel, Two-Dimensional , Heart Ventricles/metabolism , Heat-Shock Proteins/metabolism , Male , Mass Spectrometry , Organ Size , Proteins/isolation & purification , Proteomics , Rats , Rats, Inbred Strains
6.
J Proteomics ; 151: 174-181, 2017 01 16.
Article in English | MEDLINE | ID: mdl-27262223

ABSTRACT

Diagnostic tools are important for clinical management and epidemiological evaluation of Tegumentary (TL) and Visceral (VL) Leishmaniasis. Serology is not frequently used for the diagnosis of the TL form because low antibody titers and cross-reaction with VL. Therefore, it is crucial to identify specific and immunogenic antigens from species associated with the TL form. Here we employed a proteomic approach coupled to an in silico analysis and identified the most abundant and immunogenic proteins from Leishmania amazonensis, Leishmania braziliensis and Leishmania infantum. Of 16 species specific proteins, nine were from the species causative of the TL form (L. amazonensis and L. braziliensis). In silico analysis revealed 18 B-cell epitopes with 0% similarity to Trypanosoma cruzi orthologs and, therefore, less likely to crossreact with sera of patients with Chagas disease. Two proteins reacted exclusively with serum from TL patients and presented several B-cell epitopes without similarity to T. cruzi orthologs: the hypothetical protein GI 134063939 and the metallo-peptidase Clan MA(E)-Family M3. The immunoassay revealed nine peptides with strong reactivity to sera from TL patients. These proteins and peptides may be good candidates to improve the specificity and sensibility of serological tests aiming to diagnose the TL of this neglected human disease. BIOLOGICAL SIGNIFICANCE: As no gold-standard test for tegumentary leishmaniasis (TL) exists, a combination of different diagnostic techniques is often necessary to obtain precise results. Thus, the identification of species-specific, highly immunogenic and abundant proteins that stimulate the humoral immune response in the host should help in the development of serological tests for human TL. Herein we searched for these potential antigens in Leishmania species related to American Leishmaniasis (L. amazonensis, L. braziliensis and L. infantum). To this end, we employed an immunoproteomic approach using proteins from these Leishmania species and sera from TL and Visceral Leishmaniasis (VL) patients. Our study unveils specific proteins and peptides that may represent antigens that will help the efforts to improve the accuracy of serological tests to diagnose the TL form.


Subject(s)
Antigens, Protozoan/analysis , Leishmaniasis, Cutaneous/diagnosis , Leishmaniasis, Visceral/diagnosis , Serologic Tests/methods , Cross Reactions , Diagnosis, Differential , Humans , Leishmaniasis, Cutaneous/immunology , Leishmaniasis, Visceral/immunology , Neglected Diseases/diagnosis , Proteomics/methods , Protozoan Proteins/analysis , Sensitivity and Specificity , Serologic Tests/standards , Species Specificity
7.
Article in English | LILACS-Express | LILACS, VETINDEX | ID: biblio-1467261

ABSTRACT

Abstract Wilsons Plover, Charadrius wilsonia, is widely distributed in coastal areas of the Americas. This report presents the first record of breeding in this species on Coroa do Avião Island, on the coast of Pernambuco, and in the estuary of the Cardoso and Camurupim rivers, on the coast of Piauí, in northeastern Brazil, extending the known area of reproduction of this species in this region. One breeding pair was observed on October 29th 2014 on Coroa do Avião Island, and a second pair was recorded on April 6th 2016 in the Cardoso/Camurupim estuary on the Piauí coast. Both the male and the female contributed to the incubation of the eggs. The nest on Coroa do Avião island was camouflaged by the local vegetation, but despite this, the eggs were attacked by a predator. Possible predators observed on the island included Caracara plancus and domestic cats and dogs.


Resumo Charadrius wilsonia (Wilsons Plover) está amplamente distribuído pela costa das Américas. Este é o primeiro registro de reprodução no litoral de Pernambuco, Coroa do Avião, e no estuário dos rios Cardoso e Camurupim, litoral do Piauí, Brasil, ampliando a área de reprodução no Nordeste do Brasil. Foi encontrado um casal em período reprodutivo em 23 de outubro de 2014 na ilha Coroa do Avião, litoral de Pernambuco e outro registro em 06 de abril de 2016 nos estuários Cardoso e Camurupim, litoral do Piauí. Foi observado que o macho e a fêmea contribuem na incubação dos ovos. A vegetação na ilha contribui para a camuflagem do ninho, bem como na proteção dos ovos pelos predadores. Apesar da proteção ocorreu a predação do ninho na ilha Coroa do Avião. Alguns possíveis predadores foram registrados na ilha, como Caracara plancus que diariamente frequentam a área e animais domésticos como cães e gatos.

8.
Vet Parasitol ; 223: 115-9, 2016 Jun 15.
Article in English | MEDLINE | ID: mdl-27198787

ABSTRACT

Leishmania spp have a wide range of hosts, and each host can harbor several Leishmania species. Dogs, for example, are frequently infected by Leishmania infantum, where they constitute its main reservoir, but they also serve as hosts for L. braziliensis and L. amazonensis. Serological tests for antibody detection are valuable tools for diagnosis of L. infantum infection due to the high levels of antibodies induced, unlike what is observed in L. amazonensis and L. braziliensis infections. Likewise, serology-based antigen-detection can be useful as an approach to diagnose any Leishmania species infection using different corporal fluid samples. Immunogenic and secreted proteins constitute powerful targets for diagnostic methods in antigen detection. As such, we performed immunoproteomic (2-DE, western blot and mass spectrometry) and bioinformatic screening to search for reactive and secreted proteins from L. amazonensis, L. braziliensis, and L. infantum. Twenty-eight non-redundant proteins were identified, among which, six were reactive only in L. amazonensis extracts, 10 in L. braziliensis extracts, and seven in L. infantum extracts. After bioinformatic analysis, seven proteins were predicted to be secreted, two of which were reactive only in L. amazonensis extracts (52kDa PDI and the glucose-regulated protein 78), one in L. braziliensis extracts (pyruvate dehydrogenase E1 beta subunit) and three in L. infantum extracts (two conserved hypothetical proteins and elongation factor 1-beta). We propose that proteins can be suitable targets for diagnostic methods based on antigen detection.


Subject(s)
Computational Biology/methods , Dog Diseases/parasitology , Immunoproteins/isolation & purification , Leishmania/classification , Leishmaniasis/veterinary , Proteomics/methods , Animals , Dog Diseases/diagnosis , Dogs , Leishmania/isolation & purification , Leishmaniasis/diagnosis , Leishmaniasis/parasitology
9.
Genet Mol Res ; 11(1): 277-91, 2012 Feb 08.
Article in English | MEDLINE | ID: mdl-22370930

ABSTRACT

The diversity of specific bacteria taxa, such as the actinomycetes, has not been reported from the Antarctic island of Barrientos. The diversity of actinomycetes was estimated with two different strategies that use PCR-denaturing gradient gel electrophoresis. First, a PCR was applied, using a group-specific primer that allows selective amplification of actinomycete sequences. Second, a nested-PCR approach was used that allows the estimation of the relative abundance of actinomycetes within the bacterial community. Molecular identification, which was based on 16S rDNA sequence analysis, revealed eight genera of actinomycetes, Actinobacterium, Actinomyces, an uncultured Actinomycete, Streptomyces, Leifsonia, Frankineae, Rhodococcus, and Mycobacterium. The uncultured Actinomyces sp and Rhodococcus sp appear to be the prominent genera of actinomycetes in Barrientos Island soil. PCR-denaturing gradient gel electrophoresis patterns were used to look for correlations between actinomycete abundance and environmental characteristics, such as type of rookery and vegetation. There was a significant positive correlation between type of rookery and abundance of actinomycetes; soil samples collected from active chinstrap penguin rookeries had the highest actinomycete abundance. Vegetation type, such as moss, which could provide a microhabitat for bacteria, did not correlate significantly with actinomycete abundance.


Subject(s)
Actinobacteria/classification , Actinobacteria/genetics , Soil Microbiology , Animals , Antarctic Regions , Biodiversity , DNA, Bacterial , DNA, Ribosomal/genetics , Denaturing Gradient Gel Electrophoresis/methods , Molecular Sequence Data , Phylogeny , Polymerase Chain Reaction/methods , RNA, Ribosomal, 16S/genetics , Soil/analysis , Spheniscidae/microbiology
10.
J Chemother ; 23(3): 135-9, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21742581

ABSTRACT

The aim of this study was to identify phenotypic changes in a laboratory-derived strain of ertapenem-resistant Escherichia coli (Ec-ERT) when compared to its susceptible parent strain (Ec-WT). In both strains, we assessed both the effects of ertapenem via time-kill curves and the occurrence of cross resistance with other beta-lactams. The strains were compared based on growth pattern, biochemical-physiological profile and changes in the subproteome using 2D-DIGE followed by MALDI-TOF/TOF MS. To assess virulence, we employed a murine model of intraperitoneal infection in which we investigated the invasiveness of both strains. Growth persistence of the laboratory-derived resistant strain was observed via the time-kill curve assay, but cross resistance was not observed for other beta-lactams. We also observed a slower growth rate and changes in the biochemical and physiological characteristics of the drug-resistant bacteria. In the resistant strain, a total of 51 protein spots were increased in abundance relative to the wild-type strain, including an outer membrane protein A, which is related to bacterial virulence. The mouse infection assay showed a higher invasiveness of the Ec-ERT strain in relation to the Ec-WT strain. In conclusion, the alterations driven by ertapenem in E. coli reinforce the idea that antimicrobial agents may interfere in several aspects of bacterial cell biology, with possible implications for host-bacteria interactions.


Subject(s)
Anti-Bacterial Agents/pharmacology , Escherichia coli/drug effects , Escherichia coli/physiology , beta-Lactams/pharmacology , Animals , Bacterial Outer Membrane Proteins/metabolism , Drug Resistance, Bacterial , Ertapenem , Escherichia coli/metabolism , Escherichia coli/pathogenicity , Mice , Microbial Sensitivity Tests , Phenotype , Two-Dimensional Difference Gel Electrophoresis , Virulence , beta-Lactams/metabolism
11.
Vet Parasitol ; 181(2-4): 83-90, 2011 Sep 27.
Article in English | MEDLINE | ID: mdl-21641721

ABSTRACT

Dogs naturally infected with Leishmania Infantum (=L. chagasi) were treated with miltefosine using different therapeutic regimens. The animals were evaluated for clinical evolution, biochemical parameters, parasite load (by real-time PCR), cytokine levels and humoral response. After treatment and during the following 24 months, there was progressive clinical improvement and complete recovery in 50% (7/14) of the treated animals. There was a decrease in the smear positivity of the bone marrow after treatment, and there was also a gradual and constant decrease in positive cultures at the end of the follow-up period. However, the PCR detection of parasite DNA remained positive. In general, all animals presented a significant increase in parasite load 6 months after treatment. The IFN-γ levels in all the groups tended to increase during follow-up period, regardless of the miltefosine dose administered. The IL-4 and IL-10 levels of the animals tended to decrease during follow-up, except after 300 days when only IL-10 increased. The serum antibodies identified antigens that ranged from 116 kDa to less than 29 kDa in the Western blot assay. Furthermore, 300 days after treatment, qualitative and quantitative differences in the antigen profiles were observed. Antigens of 97 and 46 kDa were the most intensely recognized. Higher levels of antigen-specific Leishmania IgG were detected before and 300 days after treatment in all groups. Taking together, the improvement in the clinical symptoms was not followed by parasitological clearance, suggesting that treatment with miltefosine is not recommended, especially in endemic areas like Brazil, where children are the major victims and dogs are involved in the maintenance of the parasite cycle.


Subject(s)
Antiprotozoal Agents/therapeutic use , Dog Diseases/drug therapy , Leishmania infantum , Leishmaniasis, Visceral/veterinary , Phosphorylcholine/analogs & derivatives , Animals , Brazil/epidemiology , Dog Diseases/blood , Dog Diseases/parasitology , Dogs , Immunoglobulin G/blood , Leishmaniasis, Visceral/blood , Leishmaniasis, Visceral/drug therapy , Phosphorylcholine/therapeutic use , Time Factors
12.
J Cancer Res Clin Oncol ; 137(6): 915-25, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21465318

ABSTRACT

PURPOSE: Breast cancer is one of the major health problems of the Western world. Although the survival rate has improved with progress in screening and adjuvant systemic therapies, one-third of the patients with initial breast tumor have recurrence of the disease 10 years after the diagnosis, demonstrating the presence of micrometastasis. The underlying molecular mechanism of the disease needs to be better understood. Allied to genomics, proteomics technologies promise to be valuable for identifying new markers that improve screening, early diagnosis, prognosis and prediction of therapeutic response or toxicity, as well as the identification of new therapeutic targets. In this review, we present features of proteomic technology and its main implications, focusing on the protein profile in tumor tissues/cells through MALDI/SELDI, as well as on the current proteomic challenges in the breast cancer study. METHODS: We performed a research of protein profiling studies using mass spectrometry in breast cancer to identify potential biomarkers. RESULTS: Many protein peaks have been reported to bear significant diagnostic, prognostic or predictive value; however, the candidate biomarkers have not been validated for use in clinical patient care. CONCLUSIONS: Proteomics is under development and, despite technical barriers that precede the use of proteomics analysis in clinical practice and breast cancer complexity, MALDI-TOF/SELDI-TOF MS proteomic platforms with their innovations are powerful analytical tools for the detection of better protein biomarkers, since the studies are conducted with adequate statistical power and analytical rigor. In the near future, they will be able to fulfill their role in personalized medicine.


Subject(s)
Breast Neoplasms/chemistry , Neoplasm Proteins/analysis , Proteomics/methods , Biomarkers, Tumor/analysis , Breast Neoplasms/diagnosis , Electrophoresis, Gel, Two-Dimensional , Female , Humans , Prognosis , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
13.
Ann Trop Med Parasitol ; 104(2): 137-43, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20406580

ABSTRACT

The performance of the less expensive SYBR-Green-based PCR assay, for quantifying Leishmania chagasi in smears of bone-marrow aspirates from naturally infected, mongrel dogs, was recently compared with that of a similar PCR based on TaqMan chemistry. Aspirates were obtained from 36 infected dogs and examined for parasites by direct examination, culture, and quantitative PCR (qPCR) using specific primers (based on the parasite's kinetoplast DNA), DNA extracted from a smear, and either the SYBR-Green or TaqMan chemistries. Every aspirate smear was found PCR-positive for L. chagasi (whether the assay employed SYBR Green or TaqMan) but only 74% of the aspirates were found positive by culture and only 33% by direct, microscopical examination. There was no evidence of PCR inhibition when the DNA was collected from smears, and the parasite loads estimated using the SYBR-Green PCR were almost identical to those estimated using the TaqMan PCR (r=0.99). As a method for quantifying parasite loads in dogs infected with L. chagasi (and, probably, other mammals infected with other leishmanial parasites), PCR based on SYBR Green may therefore be an appropriate and inexpensive alternative to PCR based on TaqMan, and a reliable clinical tool.


Subject(s)
Dog Diseases/diagnosis , Leishmania infantum/isolation & purification , Leishmaniasis, Visceral/veterinary , Polymerase Chain Reaction/veterinary , Animals , Bone Marrow/virology , DNA Primers , DNA, Protozoan/analysis , Dog Diseases/parasitology , Dogs , Leishmaniasis, Visceral/parasitology , Polymerase Chain Reaction/methods , Sensitivity and Specificity , Viral Load
14.
Genes Immun ; 11(6): 447-57, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20090772

ABSTRACT

Guanine-nucleotide exchange factors (GEFs) stimulate the intrinsic GDP/GTP exchange activity of Ras and promote the formation of active Ras-GTP, which in turn controls diverse signalling networks important for the regulation of cell proliferation, survival, differentiation, vesicular trafficking, and gene expression. RasGEF1b is a GEF, whose expression is induced in macrophages on stimulation with toll-like receptor (TLR) agonists. Here, we showed that in vitro RasGEF1b expression by macrophages is mostly induced by TLR3 (poly I:C) and TLR4 (lipopolysaccharyde) through the MyD88-independent pathway. In vivo infection with the protozoan parasites Trypanosoma cruzi and Plasmodium chabaudi induced RasGEF1b in an MyD88-, TRIF-, and IFN-gamma-dependent manner. Ectopically expressed RasGEF1b was found, mostly, in the heavy membrane fraction of HEK 293T, and by confocal microscopy, it was found to be located at early endosomes. Computational modelling of the RasGEF1b-Ras interaction revealed that RasGEF1b interacts with the binding domain site of Ras, a critical region for interacting with GEFs involved in the activation of Ras-Raf-MEK-ERK pathway. More important, RasGEF1b was found to be closely associated with Ras in live cells and to trigger Ras activity. Altogether, these results indicate that on TLR activation, RasGEF1b may trigger Ras-like proteins and regulate specific biological activities described for this subtype of GTPases.


Subject(s)
Endosomes/metabolism , Toll-Like Receptors/physiology , ras Guanine Nucleotide Exchange Factors/biosynthesis , Animals , CHO Cells , Cricetinae , Cricetulus , Endosomes/chemistry , Female , HEK293 Cells , Humans , Inflammation Mediators/metabolism , Inflammation Mediators/physiology , Lipopolysaccharides/pharmacology , Macrophages, Peritoneal/chemistry , Macrophages, Peritoneal/metabolism , Macrophages, Peritoneal/pathology , Mice , Mice, Inbred C57BL , Mice, Knockout , Toll-Like Receptors/metabolism , ras Guanine Nucleotide Exchange Factors/metabolism , ras Guanine Nucleotide Exchange Factors/physiology
15.
Clin Immunol ; 131(1): 129-38, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19186111

ABSTRACT

The usefulness of a synthetic peptide in the serodiagnosis of Taenia solium human neurocysticercosis (NC) has been evaluated. Phage-displayed peptides were screened with human antibodies to scolex protein antigen from cysticercus cellulosae (SPACc). One clone was found to interact specifically with anti-SPACc IgGs. The corresponding synthetic peptide was found to be recognized in ELISA by NC patient's sera. The study was carried out with sera from 28 confirmed NC patients, 13 control sera and 73 sera from patients suffering from other infectious diseases. A 93% sensibility and a 94.3% specificity was achieved. Figures of 89% and 31.4% of sensibility and specificity were obtained in a SPACc-based ELISA. Immunoblotting of SPACc with anti-peptide antibodies revealed a single band of approximately 45 kDa in 1D and four 45 kDa isoforms in 2D-gel electrophoresis. A strong and specific immunostaining in the fibers beneath the suckers, at the base of the rostellum, and in the tissue surrounding the scolex of cysticerci was observed by immunomicroscopy. Our results show that a peptide-based immunodiagnostic of neurocisticercosis can be envisioned.


Subject(s)
Antibodies, Helminth/blood , Antigens, Helminth/immunology , Immunologic Tests/methods , Neurocysticercosis/immunology , Peptides/immunology , Taenia solium/immunology , Animals , Antibodies, Helminth/immunology , Antibody Specificity , DNA, Helminth/chemistry , DNA, Helminth/genetics , Electrophoresis, Gel, Two-Dimensional , Enzyme-Linked Immunosorbent Assay , Humans , Immunohistochemistry , Mice , Mice, Inbred BALB C , Neurocysticercosis/blood , Neurocysticercosis/diagnosis , Neurocysticercosis/parasitology , Peptide Library , Polymerase Chain Reaction , Taenia solium/isolation & purification
16.
Scand J Immunol ; 68(1): 92-102, 2008 Jul.
Article in English | MEDLINE | ID: mdl-18484953

ABSTRACT

Herein, we intended to perform flow-cytometric analyses of peripheral blood NK-cell subsets in patients with active tuberculosis (TB) and those putative resistant subjects displaying positive tuberculin skin test (TST+) and compared with TST- healthy controls. Our findings demonstrated distinct phenotypic features in TST+ as compared with TB. While lower values of NK-cells with increased frequency of CD3-CD16+ CD56- and CD3-CD16-CD56+ subsets besides lower frequency of CD3-CD16+ CD56+ NK-cells was observed in TST+, unaltered levels of NK-cells with increased levels of CD3-CD16+ CD56- NK-cells with lower frequency of CD3-CD16+ CD56+ NK-cells was found in TB. Additional analysis highlighted a shift towards increased levels of CD3-CD16-/+CD56bright NK-cells as the hallmark of TST+, whereas unaltered frequency was observed in TB. Increased levels of CD3+CD56+ cells were observed in both TST+ and TB. Further focusing on the monocyte/NK-cell network, we have reported that enhanced frequency of CD14+ CD16+ monocytes particularly observed in TST+. Outstanding were the distinct correlation profiles observed between CD3-CD16-CD56+ NK-cells and CD3+ CD56+ cells CD14+ CD16+ monocytes for TST+ and TB. These data suggested that high levels of CD3-CD16-CD56+ NK-cells aside CD14+ CD16+ monocytes as well as non-concurrent increment of CD3+ CD56+ cells, may be involved in protective mechanisms in putative tuberculosis-resistant individuals. On the other hand, the basal levels of macrophage-like monocytes despite its positive correlation with increased levels of CD3+ CD56+ cells may count for the lack of the protective immunity in patients with active tuberculosis. Further studies focusing on the cytokine profiling of peripheral blood innate immunity cells before and after chemotherapeutic treatment are currently under evaluation.


Subject(s)
Killer Cells, Natural/immunology , Lymphocyte Subsets/immunology , Tuberculosis/immunology , Adult , Female , Flow Cytometry , Humans , Immunophenotyping , Male , Middle Aged , Mycobacterium tuberculosis/immunology , Tuberculin Test
17.
Mem Inst Oswaldo Cruz ; 99(3): 283-7, 2004 May.
Article in English | MEDLINE | ID: mdl-15273801

ABSTRACT

Tuberculosis (TB) is a disease caused by Mycobacterium tuberculosis whose interaction with the host may lead to a cell-mediated protective immune response. The presence of interferon gamma (IFN-gamma) is related to this response. With the purpose of understanding the immunological mechanisms involved in this protection, the lymphoproliferative response, IFN-gamma and other cytokines like interleukin (IL-5, IL-10), and tumor necrosis factor alpha (TNF-alpha) were evaluated before and after the use of anti-TB drugs on 30 patients with active TB disease, 24 healthy household contacts of active TB patients, with positive purified protein derivative (PPD) skin tests (induration > 10 mm), and 34 asymptomatic individuals with negative PPD skin test results (induration < 5 mm). The positive lymphoproliferative response among peripheral blood mononuclear cells of patients showed high levels of IFN-gamma, TNF-alpha, and IL-10. No significant levels of IL-5 were detected. After treatment with rifampicina, isoniazida, and pirazinamida, only the levels of IFN-gamma increased significantly (p < 0.01). These results highlight the need for further evaluation of IFN-gamma production as a healing prognostic of patients treated.


Subject(s)
Antitubercular Agents/therapeutic use , BCG Vaccine/immunology , Cytokines/blood , Leukocytes, Mononuclear/immunology , Tuberculosis, Pulmonary/immunology , Adolescent , Adult , Antitubercular Agents/immunology , Biomarkers , Cytokines/biosynthesis , Female , Humans , Interferon-gamma/blood , Interleukin-10/blood , Interleukin-5/blood , Male , Middle Aged , Tuberculosis, Pulmonary/drug therapy , Tumor Necrosis Factor-alpha/analysis
18.
Mem. Inst. Oswaldo Cruz ; 99(3): 283-287, May 2004. tab, graf
Article in English | LILACS | ID: lil-361996

ABSTRACT

Tuberculosis (TB) is a disease caused by Mycobacterium tuberculosis whose interaction with the host may lead to a cell-mediated protective immune response. The presence of interferon-gamma is related to this response. With the purpose of understanding the immunological mechanisms involved in this protection, the lymphoproliferative response, IFN-gamma and other cytokines like interleukin (IL-5, IL-10), and tumor necrosis factor alpha (TNF-alfa) were evaluated before and after the use of anti-TB drugs on 30 patients with active TB disease, 24 healthy household contacts of active TB patients, with positive purified protein derivative (PPD) skin tests (induration > 10 mm), and 34 asymptomatic individuals with negative PPD skin test results (induration < 5 mm). The positive lymphoproliferative response among peripheral blood mononuclear cells of patients showed high levels of IFN-gamma, TNF-alfa, and IL-10. No significant levels of IL-5 were detected. After treatment with rifampicina, isoniazida, and pirazinamida, only the levels of IFN-gamma increased significantly (p < 0.01). These results highlight the need for further evaluation of IFN-gamma production as a healing prognostic of patients treated.


Subject(s)
Humans , Male , Female , Adolescent , Adult , Antitubercular Agents , BCG Vaccine , Cytokines , Leukocytes, Mononuclear , Tuberculosis, Pulmonary , Antitubercular Agents , Biomarkers , Cytokines , Interferon-gamma , Interleukin-10 , Interleukin-5 , Tuberculosis, Pulmonary , Tumor Necrosis Factor-alpha
SELECTION OF CITATIONS
SEARCH DETAIL
...