Obtención de fibras y gránulos de carbono para la inmovilización de enzimas

Se prepararon fibras y gránulos de carbono a partir de brea de carbón. Previa filtración, estabilización a 330°C y atmósfera de nitrógeno. Las fibras se obtuvieron por extrusión y los gránulos por inyección sobre agua. La inmovilización de lactasa por adsorción mostró que los gránulos de carbono fueron el soporte más adecuado, teniendo como criterios la menor caída de presión y la mayor capacidad de inmovilización. Los gránulos de carbono fueron caracterizados obteniéndose una densidad de partícula de 2,407 g/cm3 , una porosidad de 81,69% y un tamaño de partícula de 3 mm.Fibers and pellets of carbon were prepared from coal tar. The tar was filtrated and stabilizated in a nitrogen atmosphere at 330°C. The fibers were prepared by extrusión and pellets by injection on water. Lactase was immobilized by adsortion process. Pellets were better support than fibers, because produced lower pressure drop and upper enzyme retention. Pellets showed the folowing characteristics: density 2,407 g/cm3, porosity 81,69% and diameter 3 mm

Genetic diversity of the E Protein of Dengue Type 3 Virus

<p>Abstract</p> <p>Background</p> <p>Dengue is the most important arbovirus disease in tropical and subtropical countries. The viral envelope (E) protein is responsible for cell receptor binding and is the main target of neutralizing antibodies. The aim of this study was to analyze the diversity of the E protein gene of DENV-3. E protein gene sequences of 20 new viruses isolated in Ribeirao Preto, Brazil, and 427 sequences retrieved from GenBank were aligned for diversity and phylogenetic analysis.</p> <p>Results</p> <p>Comparison of the E protein gene sequences revealed the presence of 47 variable sites distributed in the protein; most of those amino acids changes are located on the viral surface. The phylogenetic analysis showed the distribution of DENV-3 in four genotypes. Genotypes I, II and III revealed internal groups that we have called lineages and sub-lineages. All amino acids that characterize a group (genotype, lineage, or sub-lineage) are located in the 47 variable sites of the E protein.</p> <p>Conclusion</p> <p>Our results provide information about the most frequent amino acid changes and diversity of the E protein of DENV-3.</p

Detection of DENV-4 genotype I from mosquitoes collected in the city of Manaus, Brazil

Background\ud Dengue epidemics have been reported in Brazil since 1981. In Manaus, a large city in the Amazon region, dengue is endemic with all four-virus serotypes (DENV-1, -2, -3, and -4) simultaneously causing human disease. In 2008, during a surveillance of dengue virus in mosquitoes in the district of Tancredo Neves in Manaus, 260 mosquitoes of Aedes genus were captured, identified and grouped into pools of 10 mosquitoes.\ud \ud Findings\ud RNA extracts of mosquito pools were tested by a RT-Hemi-Nested-PCR for detection of flaviviruses. One amplicon of 222 bp, compatible with dengue virus serotype 4, was obtained from a pool of Aedes aegypti. The nucleotide sequence of the amplicon indicated that the mosquitoes were infected with DENV-4 of genotype I. This virus of Asian origin has been described in Manaus in 2008 infecting acute febrile illness patients.\ud \ud Conclusion\ud This is the first report of dengue virus serotype 4 genotype I infecting Aedes aegypti in the Americas.This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

Obtención de fibras y gránulos de carbono para la inmovilización de enzimas

Fibers and pellets of carbon were prepared from coal tar. The tar was filtrated and stabilizated in a nitrogen atmosphere at 330°C. The fibers were prepared by extrusión and pellets by injection on water. Lactase was immobilized by adsortion process. Pellets were better support than fibers, because produced lower pressure drop and upper enzyme retention. Pellets showed the folowing characteristics: density 2,407 g/cm3, porosity 81,69% and diameter 3 mm.Se prepararon fibras y gránulos de carbono a partir de brea de carbón. Previa filtración, estabilización a 330°C y atmósfera de nitrógeno. Las fibras se obtuvieron por extrusión y los gránulos por inyección sobre agua. La inmovilización de lactasa por adsorción mostró que los gránulos de carbono fueron el soporte más adecuado, teniendo como criterios la menor caída de presión y la mayor capacidad de inmovilización. Los gránulos de carbono fueron caracterizados obteniéndose una densidad de partícula de 2,407 g/cm3 , una porosidad de 81,69% y un tamaño de partícula de 3 mm

Obtención de fibras y gránulos de carbono para la inmovilización de enzimas

Se prepararon fibras y gránulos de carbono a partir de brea de carbón. Previa filtración, estabilización a 330°C y atmósfera de nitrógeno. Las fibras se obtuvieron por extrusión y los gránulos por inyección sobre agua. La inmovilización de lactasa por adsorción mostró que los gránulos de carbono fueron el soporte más adecuado, teniendo como criterios la menor caída de presión y la mayor capacidad de inmovilización. Los gránulos de carbono fueron caracterizados obteniéndose una densidad de partícula de 2,407 g/cm3 , una porosidad de 81,69% y un tamaño de partícula de 3 mm

Detection of dengue virus in saliva and urine by real time RT-PCR

Early diagnosis of dengue virus (DENV) infection is important for patient management and control of dengue outbreaks. The objective of this study was to analyze the usefulness of urine and saliva samples for early diagnosis of DENV infection by real time RT-PCR. Two febrile patients, who have been attended at the General Hospital of the School of Medicine of Ribeirao Preto, Sao Paulo University were included in the study. Serum, urine and saliva samples collected from both patients were subjected to real time RT-PCR for DENV detection and quantification. Dengue RNA was detected in serum, urine and saliva samples of both patients. Patient 1 was infected with DENV-2 and patient 2 with DENV-3. Data presented in this study suggest that urine and saliva could be used as alternative samples for early diagnosis of dengue virus infection when blood samples are difficult to obtain, e.g.,in newborns and patients with hemorrhagic syndromes.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Instituto Nacional de Ciencia e Tecnologia (INCT

Detection of DENV-4 genotype I from mosquitoes collected in the city of Manaus, Brazil

Abstract Background Dengue epidemics have been reported in Brazil since 1981. In Manaus, a large city in the Amazon region, dengue is endemic with all four-virus serotypes (DENV-1, -2, -3, and -4) simultaneously causing human disease. In 2008, during a surveillance of dengue virus in mosquitoes in the district of Tancredo Neves in Manaus, 260 mosquitoes of Aedes genus were captured, identified and grouped into pools of 10 mosquitoes. Findings RNA extracts of mosquito pools were tested by a RT-Hemi-Nested-PCR for detection of flaviviruses. One amplicon of 222 bp, compatible with dengue virus serotype 4, was obtained from a pool of Aedes aegypti. The nucleotide sequence of the amplicon indicated that the mosquitoes were infected with DENV-4 of genotype I. This virus of Asian origin has been described in Manaus in 2008 infecting acute febrile illness patients. Conclusion This is the first report of dengue virus serotype 4 genotype I infecting Aedes aegypti in the Americas