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1.
FEMS Microbiol Rev ; 47(5)2023 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-37437902

RESUMO

Microbiologically influenced corrosion (MIC) is a phenomenon of increasing concern that affects various materials and sectors of society. MIC describes the effects, often negative, that a material can experience due to the presence of microorganisms. Unfortunately, although several research groups and industrial actors worldwide have already addressed MIC, discussions are fragmented, while information sharing and willingness to reach out to other disciplines are limited. A truly interdisciplinary approach, which would be logical for this material/biology/chemistry-related challenge, is rarely taken. In this review, we highlight critical non-biological aspects of MIC that can sometimes be overlooked by microbiologists working on MIC but are highly relevant for an overall understanding of this phenomenon. Here, we identify gaps, methods, and approaches to help solve MIC-related challenges, with an emphasis on the MIC of metals. We also discuss the application of existing tools and approaches for managing MIC and propose ideas to promote an improved understanding of MIC. Furthermore, we highlight areas where the insights and expertise of microbiologists are needed to help progress this field.


Assuntos
Biofilmes , Metais , Corrosão
2.
Braz. j. biol ; 82: 1-7, 2022. ilus, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1468446

RESUMO

Shewanella xiamenensis G5-03 was observed to decolorize the azo dye Congo red in synthetic wastewater. The influence of some factors on the dye decolorization efficiency was evaluated. The optimal decolorization conditions were temperature 30-35 °C, pH 10.0, incubation time 10 h, and static condition. The kinetic of Congo red decolorization fitted to the Michaelis–Menten model (Vmax = 111.11 mg L-¹ h-¹ and Km = 448.3 mg L-¹). The bacterium was also able to degrade benzidine, a product of azo bond breakage of the Congo red, which contributed to reduce the phytotoxicity. The ability of S. xiamenensis G5-03 for simultaneous decolorization and degradation of Congo red shows its potential application for the biological treatment of wastewaters containing azo dyes.


Shewanella xiamenensis G5-03 foi capaz de descolorir o corante azo vermelho Congo em água residuária sintética. A influência de alguns fatores na eficiência da descoloração do corante foi avaliada. As condições ótimas de descoloração foram temperatura de 30-35 °C, pH 10,0 e condições estáticas. A cinética de descoloração do vermelho Congo se ajustou ao modelo de Michaelis–Menten (Vmax = 111,11 mg L-¹ h-¹ and Km = 448,3 mg L-¹). A bactéria também foi capaz de degradar a benzidina, um produto da quebra da ligação azo do vermelho Congo, o que contribuiu para a redução da fitotoxicidade. A habilidade da S. xiamenensis G5-03 em simultaneamente descolorir e degradar o vermelho Congo demostra seu potencial de aplicação no tratamento de águas residuárias contendo corantes azo.


Assuntos
Benzidinas/isolamento & purificação , Shewanella/enzimologia , Águas Residuárias/análise , Águas Residuárias/toxicidade
3.
Braz. j. biol ; 822022.
Artigo em Inglês | LILACS-Express | LILACS, VETINDEX | ID: biblio-1468633

RESUMO

Abstract Shewanella xiamenensis G5-03 was observed to decolorize the azo dye Congo red in synthetic wastewater. The influence of some factors on the dye decolorization efficiency was evaluated. The optimal decolorization conditions were temperature 30-35 °C, pH 10.0, incubation time 10 h, and static condition. The kinetic of Congo red decolorization fitted to the MichaelisMenten model (Vmax = 111.11 mg L-1 h-1 and Km = 448.3 mg L-1). The bacterium was also able to degrade benzidine, a product of azo bond breakage of the Congo red, which contributed to reduce the phytotoxicity. The ability of S. xiamenensis G5-03 for simultaneous decolorization and degradation of Congo red shows its potential application for the biological treatment of wastewaters containing azo dyes.


Resumo Shewanella xiamenensis G5-03 foi capaz de descolorir o corante azo vermelho Congo em água residuária sintética. A influência de alguns fatores na eficiência da descoloração do corante foi avaliada. As condições ótimas de descoloração foram temperatura de 30-35 °C, pH 10,0 e condições estáticas. A cinética de descoloração do vermelho Congo se ajustou ao modelo de MichaelisMenten (Vmax = 111,11 mg L-1 h-1 and Km = 448,3 mg L-1). A bactéria também foi capaz de degradar a benzidina, um produto da quebra da ligação azo do vermelho Congo, o que contribuiu para a redução da fitotoxicidade. A habilidade da S. xiamenensis G5-03 em simultaneamente descolorir e degradar o vermelho Congo demostra seu potencial de aplicação no tratamento de águas residuárias contendo corantes azo.

4.
Braz. j. biol ; 82: e237386, 2022. graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1249227

RESUMO

Shewanella xiamenensis G5-03 was observed to decolorize the azo dye Congo red in synthetic wastewater. The influence of some factors on the dye decolorization efficiency was evaluated. The optimal decolorization conditions were temperature 30-35 °C, pH 10.0, incubation time 10 h, and static condition. The kinetic of Congo red decolorization fitted to the Michaelis­Menten model (Vmax = 111.11 mg L-1 h-1 and Km = 448.3 mg L-1). The bacterium was also able to degrade benzidine, a product of azo bond breakage of the Congo red, which contributed to reduce the phytotoxicity. The ability of S. xiamenensis G5-03 for simultaneous decolorization and degradation of Congo red shows its potential application for the biological treatment of wastewaters containing azo dyes.


Shewanella xiamenensis G5-03 foi capaz de descolorir o corante azo vermelho Congo em água residuária sintética. A influência de alguns fatores na eficiência da descoloração do corante foi avaliada. As condições ótimas de descoloração foram temperatura de 30-35 °C, pH 10,0 e condições estáticas. A cinética de descoloração do vermelho Congo se ajustou ao modelo de Michaelis­Menten (Vmax = 111,11 mg L-1 h-1 and Km = 448,3 mg L-1). A bactéria também foi capaz de degradar a benzidina, um produto da quebra da ligação azo do vermelho Congo, o que contribuiu para a redução da fitotoxicidade. A habilidade da S. xiamenensis G5-03 em simultaneamente descolorir e degradar o vermelho Congo demostra seu potencial de aplicação no tratamento de águas residuárias contendo corantes azo.


Assuntos
Compostos Azo , Vermelho Congo , Benzidinas , Biodegradação Ambiental , Shewanella , Corantes
5.
Braz J Biol ; 82: e237386, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33978076

RESUMO

Shewanella xiamenensis G5-03 was observed to decolorize the azo dye Congo red in synthetic wastewater. The influence of some factors on the dye decolorization efficiency was evaluated. The optimal decolorization conditions were temperature 30-35 °C, pH 10.0, incubation time 10 h, and static condition. The kinetic of Congo red decolorization fitted to the Michaelis-Menten model (Vmax = 111.11 mg L-1 h-1 and Km = 448.3 mg L-1). The bacterium was also able to degrade benzidine, a product of azo bond breakage of the Congo red, which contributed to reduce the phytotoxicity. The ability of S. xiamenensis G5-03 for simultaneous decolorization and degradation of Congo red shows its potential application for the biological treatment of wastewaters containing azo dyes.


Assuntos
Compostos Azo , Vermelho Congo , Benzidinas , Biodegradação Ambiental , Corantes , Shewanella
6.
Sci Total Environ ; 650(Pt 2): 2499-2511, 2019 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-30293004

RESUMO

Environmental concerns have been changing the way of looking for solutions to problems. The hydrosphere, together with its biosphere, has been feeling the impact of many pollutants, used for instance in the marine industry for economic reasons or lack of knowledge of their effects. In particular biocides, applied as coatings in paints, are released into the waters becoming toxic and persistent extending their action to an area far beyond the initial coated surface they should protect. In order to minimize these side effects, two biocides, Irgarol (I) and Econea (E), were covalently attached to polyurethane (PU) and foul-release silicone based (PDMS) marine paints through an isocyanate linker. Their antifouling bioactivity was better in PDMS coatings, both for single (Econea) and combined biocides (E/I ratio = 1.5) with contents lower than 0.6 wt%. The treated samples remained almost clean after more than one year immersion in the Portuguese shore of the Atlantic Ocean, and after about 24 weeks under the tropical conditions of Singapore (Fouling rate < 1%). Complementary biofilm adhesion susceptibility tests against Pseudoalteromonas tunicata D2 showed adhesion reduction higher than 90% for PU formulations containing single biocides and close to 100% for PDMS with combined biocides. The eco-toxicity assessment evidenced a low environmental impact, in accordance with the European standards. In addition, shipping field trial tests showed the best antifouling performance for the Econea-based PDMS formulations (E = 0.6 wt%), which remained clean for about nine months in open seawaters, proving the efficacy of this non-release strategy, when applied under dynamic conditions.


Assuntos
Fenômenos Fisiológicos Bacterianos/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Incrustação Biológica/prevenção & controle , Diatomáceas/efeitos dos fármacos , Desinfetantes/farmacologia , Pirróis/farmacologia , Triazinas/farmacologia , Pintura/análise , Navios
7.
Eur J Cardiovasc Nurs ; 16(5): 409-417, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28565966

RESUMO

BACKGROUND: Vascular complications are still common in the catheterization laboratory setting. However, no risk scores for their prediction have been described. With a view to bridging this gap, the present study sought to develop and validate a score for prediction of vascular complications associated with arterial access in patients undergoing interventional cardiology procedures. METHODS: This prospective multicenter cohort study included adult patients who underwent cardiac catheterization via the femoral or radial route. The outcomes of interest were: access site hematoma; major and minor bleeding; and retroperitoneal hemorrhage, pseudoaneurysm, or arteriovenous fistula requiring surgical repair. Past medical history as well as pre-procedural, intra-procedural, and post-procedural variables were collected. Patients were randomly allocated to the derivation or validation cohorts at a 2:1 ratio. The following equation constituted the score: (>6F introducer sheath×4.0)+(percutaneous coronary intervention×2.5)+(history of vascular complication after prior interventional cardiology procedure×2.0)+(prior use of warfarin or phenprocoumon×2.0)+(female sex×1.5)+(age⩾60 years×1.5). The maximum score is 13.5 points. RESULTS: A score dichotomized at ⩾3 (best cutoff for balancing sensitivity and specificity) was moderately accurate (sensitivity=0.66 (95% confidence interval: 0.59-0.73); specificity=0.59 (95% confidence interval: 0.56-0.61)). Patients with a score ⩾3 were at increased risk of complications (odds ratio: 2.95; 95% confidence interval: 2.22-3.91). CONCLUSIONS: This study yielded a score that is capable of predicting vascular complications and easily applied in daily practice by providers working in the catheterization laboratory setting.


Assuntos
Cateterismo Cardíaco/efeitos adversos , Cateterismo Cardíaco/normas , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Procedimentos Cirúrgicos Cardíacos/normas , Complicações Pós-Operatórias/etiologia , Medição de Risco/normas , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Valor Preditivo dos Testes , Estudos Prospectivos
8.
Med Vet Entomol ; 31(2): 192-199, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28117911

RESUMO

Morphological and structural features of the sperm of the Triatoma brasiliensis Neiva, 1911 (Hemiptera: Reduviidae) species complex were examined in this first study investigating the sperm of Heteroptera and the genus Triatoma. Males were dissected and their seminal vesicles removed. For measurement, seminal vesicles were squashed on glass slides, spread, fixed and observed under a photomicroscope. The images were analysed and measures of sperm were made. Data were analysed using one-way analysis of variance and Tukey's test to detect differentiation among taxa. Furthermore, seminal vesicles were prepared for studies of transmission electron microscopy. All taxa studied showed polymorphic (short and long) sperm. The sperm of Triatoma brasiliensis macromelasoma was significantly longer (in total length) than that of the other four members of the complex, which supports the hypothesis of hybrid speciation of this member of the complex as an increase in the size of typical hybrids under heterosis was previously shown. The sperm cells of the five taxa have similar ultrastructural morphology. The ultrastructural features observed confirm the hypothesis, raised by previous studies, that they are synapomorphic to the suborder Heteroptera.


Assuntos
Insetos Vetores/classificação , Insetos Vetores/ultraestrutura , Triatoma/classificação , Triatoma/ultraestrutura , Animais , Masculino , Microscopia Eletrônica de Transmissão , Espermatozoides/ultraestrutura
9.
Phys Chem Chem Phys ; 19(2): 1181-1189, 2017 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-27942644

RESUMO

A comprehensive study of the self-assembly in water of a lipopeptide consisting of a sequence of l-proline, l-arginine and l-tryptophan with a hydrocarbon chain has been performed. Fluorescence assays were used to determine the critical aggregation concentration. In situ small-angle X-ray scattering (SAXS) and molecular dynamics simulations showed the presence of spherical micelles with diameters around 6 nm. In agreement with these results, cryo-TEM images showed globular aggregates with diameters ranging from ≈4 nm up to ≈9 nm. Furthermore, the lipopeptide catalytic activity has been tested for the direct aldol reaction between cyclohexanone and p-nitrobenzaldehyde, and we have observed that the self-association of the organocatalyst played a critical role in the enhanced activity. Water affects the selectivity, and poor results are obtained under neat reaction conditions. The location of the catalytic groups at the lipopetide/water solvent interface also endowed unusual selectivity in the catalyzed aldol reactions. Under optimized reaction conditions, high yields (up to >99%), good enantioselectivity (ee up to 85%) and high diastereoselectivity (ds up to 92 : 8) were obtained.


Assuntos
Lipopeptídeos/química , Micelas , Aldeídos/química , Arginina/química , Benzaldeídos/química , Catálise , Microscopia Crioeletrônica , Cicloexanonas/química , Lipopeptídeos/síntese química , Lipopeptídeos/ultraestrutura , Simulação de Dinâmica Molecular , Prolina/química , Espalhamento a Baixo Ângulo , Triptofano/química , Água/química , Difração de Raios X
10.
Braz. j. biol ; 76(3): 764-773, tab, graf
Artigo em Inglês | LILACS | ID: lil-785050

RESUMO

Abstract This study evaluated the abundance and spatial-temporal distribution of the shrimp Xiphopenaeus kroyeri in the coastal region of Macaé, state of Rio de Janeiro, southeastern Brazil. Monthly samples were obtained from March 2008 to February 2010 in six stations located in Inner (5, 10 and 15m depth) and Outer (25, 35 and 45m depth) areas. It was used a commercial fishery boat equipped with an otter-trawl net (3.5 m mouth width, mesh size 20mm and 15mm in the cod end). Water samples were taken for determination of temperature and salinity, and sediment samples for determination of texture and organic matter content. A total of 7146 shrimps were sampled. About 95% of all shrimps were caught in the shallow area, i.e., depths <20m. Greatest abundances were recorded in winter and spring. No significant correlation was observed between sediment (phi) and abundance. The distribution of X. kroyeri in the studied area was closely related to seasonal cold waterfront of the South Atlantic Central Water (SACW) and temperature was the main factor affecting the species abundance.


Resumo Este estudo avaliou a abundância e a distribuição espaço–temporal do camarão Xiphopenaeus kroyeri na área costeira da região de Macaé, estado do Rio de Janeiro no sudeste do Brasil. As coletas foram realizadas mensalmente de março de 2008 a fevereiro de 2010 em seis transectos localizados na área interna (5, 10 e 15m profundidade) e na área externa (25,35 e 45m profundidade). Foi utilizado um barco de pesca comercial equipado com uma rede de arrasto tipo otter-trawl (3,5m abertura de boca, 20mm de malha e 15mm de ensacador). Foram obtidas amostras de água para determinação da temperatura e da salinidade e amostras de sedimento para determinação da granulometria e teor de matéria orgânica. Um total estimado de 7146 camarões foi amostrado. Aproximadamente, 95% de todos os camarões foram capturados “Inner Area”, ou seja, profundidades <20m. As maiores abundâncias foram registradas no inverno e na primavera. Não houve correlação significativa entre o sedimento (phi) e abundância. De acordo com os resultados deste estudo, a distribuição do X. kroyeri na área de estudo está intimamente ligada à sazonalidade da frente térmica da ACAS e a temperatura é o principal fator que afetou a abundância da espécie.


Assuntos
Animais , Monitoramento Ambiental/métodos , Penaeidae , Análise Espaço-Temporal , Estações do Ano , Temperatura , Brasil , Dinâmica Populacional , Densidade Demográfica , Ecossistema , Salinidade
11.
Braz J Biol ; 76(3): 764-73, 2016 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-27097079

RESUMO

This study evaluated the abundance and spatial-temporal distribution of the shrimp Xiphopenaeus kroyeri in the coastal region of Macaé, state of Rio de Janeiro, southeastern Brazil. Monthly samples were obtained from March 2008 to February 2010 in six stations located in Inner (5, 10 and 15m depth) and Outer (25, 35 and 45m depth) areas. It was used a commercial fishery boat equipped with an otter-trawl net (3.5 m mouth width, mesh size 20mm and 15mm in the cod end). Water samples were taken for determination of temperature and salinity, and sediment samples for determination of texture and organic matter content. A total of 7146 shrimps were sampled. About 95% of all shrimps were caught in the shallow area, i.e., depths <20m. Greatest abundances were recorded in winter and spring. No significant correlation was observed between sediment (phi) and abundance. The distribution of X. kroyeri in the studied area was closely related to seasonal cold waterfront of the South Atlantic Central Water (SACW) and temperature was the main factor affecting the species abundance.


Assuntos
Monitoramento Ambiental/métodos , Penaeidae , Análise Espaço-Temporal , Animais , Brasil , Ecossistema , Densidade Demográfica , Dinâmica Populacional , Salinidade , Estações do Ano , Temperatura
12.
J Mater Chem B ; 4(8): 1405-1413, 2016 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32263107

RESUMO

Peptide-based scaffolds are a frontier research area in materials science with widespread impact in biomedical engineering. In this paper, we describe a hybrid material formulated through the conjugation of electrospun polycaprolactone (PCL) fibers and micro/nanotubes of l,l-diphenylalanine (FF-MNTs). Morphology and crystallinity of the composite matrices are investigated using a wide range of analytical techniques including electron microscopy, thermal analyses, X-ray diffraction and micro-tomography. Peptide assemblies are found to produce deep modifications on the microstructure of PCL fibers, impacting average diameters, crystallinity degree and porous size in the polymer network. These changes are correlated with mechanical properties of the resulting scaffolds, whose strength is found to exhibit a brittle-to-ductile transition upon increasing the amount of FF-MNTs and lead to enhanced Young's moduli of polymer fibers. The PCL/FF-MNTs composites were tested for the drug delivery application of a lipophilic drug, benzocaine. In vitro permeation studies have shown that these polymer/peptide hybrids are able to produce a steady release of benzocaine over periods of up to ∼13 hours, much higher than commercially available gel formulations. Enzymatic tests have shown a significant increment in biodegradation rates in PCL/FF-MNTs hybrids containing higher peptide amounts, which exhibited almost 100% weight loss against only 10% found in pure PCL. Our findings indicate that using PCL/FF-MNTs materials is a simple route towards achieving enhanced mechanical strength of PCL networks that have the ability to promote controlled drug delivery from a completely biodegradable matrix.

13.
Aust Dent J ; 58(3): 326-32, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23981214

RESUMO

BACKGROUND: Orthodontic procedures are often limited by the presence of bone defects caused by trauma, periodontal diseases or surgeries, thus requiring the development of materials capable to compensate such deficiencies. Since bone morphogenetic proteins (BMPs) are indicative of bone reconstitution, this study aimed to evaluate histological and immunohistochemically the temporal location of BMP-2 and BMP-4 in osteoblasts of rat alveolar wounds filled with demineralized human dentine matrix (DHDM), used as a graft material. METHODS: After extraction of the upper second molars, the left side alveoli were filled with DHDM and the right side served as the control. The animals were euthanized after 3, 5, 10 and 14 days of surgery. After fixation, demineralization and paraffin embedding, representative samples of each group were stained with H&E and immunohistochemically evaluated. RESULTS: The data showed a statistically significant (p < 0.05) increased number of osteoblasts positively immunostained for BMP-2 and BMP-4 on the experimental side (left) at 10 days. Our results also showed that even when not degraded, dentine matrix was incorporated to new bone formation after 14 days of surgery. CONCLUSIONS: The results suggest that DHDM acts as a scaffold for osteoblast differentiation, actively yielding new bone formation, and it may represent an effective bone implant material.


Assuntos
Proteína Morfogenética Óssea 2/metabolismo , Proteína Morfogenética Óssea 4/metabolismo , Dentina , Osteoblastos/metabolismo , Osteogênese/fisiologia , Alvéolo Dental/fisiopatologia , Cicatrização/fisiologia , Animais , Proteína Morfogenética Óssea 2/análise , Proteína Morfogenética Óssea 4/análise , Dentina/metabolismo , Humanos , Ratos
14.
Appl Radiat Isot ; 71 Suppl: 81-6, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22963980

RESUMO

Due to the variability of neutron spectrum within the same environment, it is essential that the spectral distribution as a function of energy should be characterized. The precise information allows radiological quantities establishment related to that spectrum, but it is necessary that a spectrometric system covers a large interval of energy and an unfolding process is appropriate. This paper proposes use of a technique of Artificial Intelligence (AI) called genetic algorithm (GA), which uses bio-inspired mathematical models with the implementation of a specific matrix to unfolding data obtained from a combination of TLDs embedded in a BS system to characterize the neutron spectrum as a function of energy. The results obtained with this method were in accordance with reference spectra, thus enabling this technique to unfold neutron spectra with the BS-TLD system.


Assuntos
Nêutrons , Dosimetria Termoluminescente , Algoritmos , Ciclotrons , Modelos Teóricos , Análise Espectral
15.
Braz. j. microbiol ; 43(2): 739-743, Apr.-June 2012. tab
Artigo em Inglês | LILACS | ID: lil-644491

RESUMO

Human rhinoviruses (HRVs) are the major cause of the common cold. HRVs were recently reclassified into the Enterovirus genus (HEV) in the Picornaviridae family. HRVs and other members of the HEV genus share many common features, including sense RNA genomes and partial nucleotide sequence identity. The aim of this study was to evaluate different HRV detection strategies. Samples from adults with acute respiratory infection (n = 291) who were treated in Sao Paulo Hospital (2001-2003) were tested using three assays. The first assay detected picornaviruses by RT-PCR and hybridization, the second detected rhinoviruses using RT-PCR/sequencing, and the third differentiated HRV from HEV using duplex semi-nested-RT-PCR. Analysis of the results obtained from the first two strategies revealed 83% concordance. Discordant samples were then evaluated by the third protocol, and 82% were negative. The picornavirus detection protocol was more sensitive but less specific than the rhinovirus detection protocols. The semi-nested protocol utilized in the present study was less sensitive and was not useful in differentiating HRV from HEV. Sequencing assays examining different genes would address the best strategy of confirming rhinovirus and enterovirus infections.


Assuntos
Humanos , Sequência de Bases , Resfriado Comum , Genoma Viral , Hibridização Genética , Técnicas In Vitro , Infecções Respiratórias/genética , Infecções por Picornaviridae/genética , Picornaviridae/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Reação em Cadeia da Polimerase/métodos , Rhinovirus/genética , Diagnóstico , Métodos , Pacientes
16.
Arch Biochem Biophys ; 520(2): 88-98, 2012 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-22387434

RESUMO

The Hsp70 is an essential molecular chaperone in protein metabolism since it acts as a pivot with other molecular chaperone families. Several co-chaperones act as regulators of the Hsp70 action cycle, as for instance Hip (Hsp70-interacting protein). Hip is a tetratricopeptide repeat protein (TPR) that interacts with the ATPase domain in the Hsp70-ADP state, stabilizing it and preventing substrate dissociation. Molecular chaperones from protozoans, which can cause some neglected diseases, are poorly studied in terms of structure and function. Here, we investigated the structural features of Hip from the protozoa Leishmania braziliensis (LbHip), one of the causative agents of the leishmaniasis disease. LbHip was heterologously expressed and purified in the folded state, as attested by circular dichroism and intrinsic fluorescence emission techniques. LbHip forms an elongated dimer, as observed by analytical gel filtration chromatography, analytical ultracentrifugation and small angle X-ray scattering (SAXS). With the SAXS data a low resolution model was reconstructed, which shed light on the structure of this protein, emphasizing its elongated shape and suggesting its domain organization. We also investigated the chemical-induced unfolding behavior of LbHip and two transitions were observed. The first transition was related to the unfolding of the TPR domain of each protomer and the second transition of the dimer dissociation. Altogether, LbHip presents a similar structure to mammalian Hip, despite their low level of conservation, suggesting that this class of eukaryotic protein may use a similar mechanism of action.


Assuntos
Proteínas de Choque Térmico HSP70/química , Proteínas de Choque Térmico HSP70/ultraestrutura , Leishmania braziliensis/enzimologia , Modelos Químicos , Modelos Moleculares , Conformação Proteica
17.
Braz J Microbiol ; 43(2): 739-43, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24031885

RESUMO

Human rhinoviruses (HRVs) are the major cause of the common cold. HRVs were recently reclassified into the Enterovirus genus (HEV) in the Picornaviridae family. HRVs and other members of the HEV genus share many common features, including sense RNA genomes and partial nucleotide sequence identity. The aim of this study was to evaluate different HRV detection strategies. Samples from adults with acute respiratory infection (n = 291) who were treated in Sao Paulo Hospital (2001-2003) were tested using three assays. The first assay detected picornaviruses by RT-PCR and hybridization, the second detected rhinoviruses using RT-PCR/sequencing, and the third differentiated HRV from HEV using duplex semi-nested-RT-PCR. Analysis of the results obtained from the first two strategies revealed 83% concordance. Discordant samples were then evaluated by the third protocol, and 82% were negative. The picornavirus detection protocol was more sensitive but less specific than the rhinovirus detection protocols. The semi-nested protocol utilized in the present study was less sensitive and was not useful in differentiating HRV from HEV. Sequencing assays examining different genes would address the best strategy of confirming rhinovirus and enterovirus infections.

18.
Eur Phys J E Soft Matter ; 34(8): 83, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21870217

RESUMO

The structure of a complex between hydrated DNA and a non-cationic lipid is studied, including its phase diagram. The complex is spontaneously formed by adding DNA fragments (ca. 150 base pairs in length) to non-cationic lipids and water. The self-assembly process often leads to highly ordered structures. The structures were studied by combining X-ray scattering, fluorescence and polarized microscopy, as well as freeze-fracture experiments with transmission electron microscopy. We observe a significant increase of the smectic order as DNA is incorporated into the water layers of the lamellar host phase, and stabilization of single phase domains for large amounts of DNA. The effect of confinement on DNA ordering is investigated by varying the water content, following three dilution lines. A rich polymorphism is found, ranging from weakly correlated DNA-DNA in-plane organizations to highly ordered structures, where transmembrane correlations lead to the formation of columnar rectangular and columnar hexagonal superlattices of nucleotides embedded between lipid lamellae. From these observations, we suggest that addition of DNA to the lamellar phase significantly restricts membrane fluctuations above a certain concentration and helps the formation of the lipoplex. The alteration of membrane steric interactions, together with the appearance of interfacial interactions between membranes and DNA molecules may be a relevant mechanism for the emergence of highly ordered structures in the concentrated regime.


Assuntos
DNA/química , Lipídeos/química , Animais , Bovinos , DNA/metabolismo , Metabolismo dos Lipídeos , Água/química
19.
Br J Sports Med ; 45(2): 91-4, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19955164

RESUMO

BACKGROUND: non-steroidal anti-inflammatory drugs (NSAIDs) are frequently used in sports medicine to reduce time of incapacity. OBJECTIVE: to describe the frequency of NSAIDs use by athletes in the XV Pan-American Games. METHODS: all athletes who were tested by the anti-doping control filled a form. The voluntarily declared medications were recorded and categorised according to sport modality, sex, region and control situation according to the World Anti-Doping Agency. RESULTS: among the 1261 athletes tested (231 out-competition (OC) and 1030 in-competition (IC); 733 men and 528 women), 63% reported use of drugs, NSAIDs being the most frequently (64% of users) used medications. The use of medications was not significantly different between sexes or among different regions of the world. The number of users of only one type of NSAID was higher than those who used more than one type of NSAIDs or a combination with analgesics (335 vs 168 cases). IC reports presented higher use of NSAIDs than OC. CONCLUSION: athletes tested by the anti-doping control of the XV Pan-American Games reported a high frequency of NSAIDs use. The frequent utilisation in competition suggests that these medications might be used as ergogenic aid.


Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Esportes/estatística & dados numéricos , Adulto , Desempenho Atlético/fisiologia , Dopagem Esportivo , Feminino , Humanos , Masculino , Dor/prevenção & controle , Adulto Jovem
20.
Genet Mol Res ; 7(4): 1344-52, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-19065769

RESUMO

Soft tissue sarcomas (STS) are tumors of mesodermal origin, comprising about 1% of all adult neoplasms. Management of such tumors is an important medical challenge. TP53 codon 72 polymorphism results in either the arginine or proline form of the p53 protein; several studies have investigated whether codon 72 polymorphisms are risk and prognostic factors for cancer. We investigated p53 codon 72 polymorphism (Arg72Pro) frequencies with respect to the susceptibility and the clinical outcome of patients with STS. A series of 100 STS were genotyped for the p53 Arg72Pro polymorphism using polymerase chain reaction. Genotype frequencies were compared to a group of 85 healthy donors (controls). Possible associations between polymorphic genotypes, clinicopathological factors and survival of STS patients were also investigated. Genotypic frequencies obtained for STS patients did not significantly differ from that obtained for controls. In the STS group, p53 codon 72 polymorphic variants were not significantly associated with gender, age, tumor size, clinical stage, tumor grade, histology, or nodal or distant metastasis. The five-year overall survival rate for the STS group was 48%; it was significantly affected by tumor grade, clinical stage, and nodal and distant metastasis. Soft tissue sarcoma patients with the Pro/Pro variant had a reduced survival rate (30%), when compared to the p53 Arg/Arg (45%) and the p53 Arg/Pro groups (55%). However, the differences between these groups were not significant (P = 0.44).


Assuntos
Códon/genética , Polimorfismo Genético , Sarcoma/genética , Proteína Supressora de Tumor p53/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Arginina/genética , Feminino , Frequência do Gene , Genes p53 , Predisposição Genética para Doença , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Prolina/genética , Adulto Jovem
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