974 resultados para POLYMERASE-GAMMA


Relevância:

20.00% 20.00%

Publicador:

Resumo:

A short duration burst reminiscent of a soft gamma-ray repeater/anomalous X-ray pulsar behaviour was detected in the direction of LS I +61 303 by the Swift satellite. While the association with this well known gamma-ray binary is likely, a different origin cannot be excluded. Aims. We explore the error box of this unexpected flaring event and establish the radio, near-infrared and X-ray sources in our search for any peculiar alternative counterpart. Methods. We carried out a combined analysis of archive Very Large Array radio data of LS I +61 303 sensitive to both compact and extended emission. We also reanalysed previous near infrared observations with the 3.5 m telescope of the Centro Astronómico Hispano Alemán and X-ray observations with the Chandra satellite. Results. Our deep radio maps of the LS I +61 303 environment represent a significant advancement on previous work and 16 compact radio sources in the LS I +61 303 vicinity are detected. For some detections, we also identify near infrared and X-ray counterparts. Extended emission features in the field are also detected and confirmed. The possible connection of some of these sources with the observed flaring event is considered. Based on these data, we are unable to claim a clear association between the Swift-BAT flare and any of the sources reported here. However, this study represents the most sophisticated attempt to determine possible alternative counterparts other than LS I +61 303.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Many viral diseases, including leafroll, which is of great economic importance, affect grapevines (Vitis spp.). A complex of eight viruses [Grapevine leafroll-associated virus (GLRaV) -1 to 8] is associated with this disease. The objective of this study was to compare the variability of the 3' terminal region of the polymerase gene of three isolates of GLRaV-3 (Grapevine leafroll-associated virus-3), from Submédio do Vale do Rio São Francisco (Petrolina-PE) with that of other isolates available at the GenBank, including an isolate from North America and another from Southern Brazil. The viral RNA was extracted from three infected ELISA reactive plants and a fragment of 340 bp was amplified, by RT-PCR, using primers that recognize that portion of the polymerase gene found between nucleotides 8267 and 8606. The three isolates from Vale do Rio São Francisco named Pet-1, Pet-2 and Pet-3, showed similarities ranging from 98% and 94%, respectively to the isolates from North America (AF037268) and Southern Brazilian (AF438411). Considering the whole genome, the main variation found was one amino acid change at position 2766 (F2766Y). These preliminary data indicate the existence of a natural variation among GLRaV-3 isolates from grapevines. This could be due to the vegetative propagation and long cycle of the plant, associated with the error-prone nature of RNA-dependent RNA polymerase.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Leaf scald of barley caused by Rhynchosporium secalis is an important disease in Argentina. The fungus is a necrotrophic pathogen which survives in stubble, seeds and weeds. Isolation of R. secalis from seeds on artificial media usually has not been successful due to the slow growth rate of the pathogen and strong inhibition by contaminants. The objective in this work was to detect R. secalis in different genotypes of barley seeds in Argentina using the polymerase chain reaction (PCR)-based diagnostic assay. Four barley genotypes were tested in 2004: Quilmes Ayelén, Quilmes Alfa, Barke and Maltería Pampa 1004. The previously described RS8 and RS9 primers were used for the detection of R. secalis in barley seeds. A 264-bp single band was obtained for each cultivar showing the presence of R. secalis. The use of specific primers was efficient in the detection of R. secalis in barley seeds in Argentina and could be used for routine diagnosis, epidemiology and seed transmission studies. This is the first report on the detection of R. secalis in barley seeds in Argentina.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Bovine leukaemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). In Argentina, where a program to eradicate EBL has been introduced, sensitive and reliable diagnosis has attained high priority. Although the importance of the agar gel immunodiffusion test remains unchanged for routine work, an additional diagnostic technique is necessary to confirm cases of sera with equivocal results or of calves carrying maternal antibodies.Utilizing a nested shuttle polymerase chain reaction, the proviral DNA was detected from cows experimentally infected with as little as 5 ml of whole blood from BLV seropositive cows that were nonetheless normal in haematological terms. It proved to be a very sensitive technique, since it rapidly revealed the presence of the provirus, frequently at 2 weeks postinoculation and using a two-round procedure of nested PCR taking only 3 hours. Additionally, the primers used flanked a portion of the viral genome often employed to differentiate BLV type applying BamHI digestion. It is concluded that this method might offer a highly promising diagnostic tool for BLV infection.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Bovine genital campylobacteriosis is a common venereal disease of cattle; the prevalence of this disease can be underestimated mostly because of the nature of the etiological agent, the microaerobic Campylobacter fetus subspecies venerealis. The purpose of the current study was to evaluate the utilization of polymerase chain reaction (PCR) in the diagnosis of genital campylobacteriosis in samples obtained from bull prepuce aspirate, cow cervical mucus, and abomasum contents of aborted fetuses, collected into enrichment medium. Five different DNA extraction protocols were tested: thermal extraction, lysis with proteinase K, lysis with guanidine isothiocyanate, lysis with DNAzol, and lysis with hexadecyltrimethylammonium bromide (CTAB). The specificity, sensitivity, and technical application of the PCR assay were also evaluated with clinical samples and compared to bacterial isolation by standard culture. DNA extraction by the CTAB protocol provided better results in PCR, and it was able to detect 63 colony-forming units per ml of C. fetus. Out of 277 clinical samples tested, 68 (24%) were positive for Campylobacter fetus using PCR, while only 8 (2.8%) of the samples were positive by bacterial isolation in solid medium, proving the superiority of the PCR technique when compared to the standard isolation method, and providing evidence for its usefulness as a better screening test in cattle for the diagnosis of bovine genital campylobacteriosis.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The presence of anti leptospiral agglutinins (microscopic agglutination test - MAT) and DNA of leptospires was investigated in the kidney and urine (Polymerase Chain Reaction - PCR) in samples collected at the time of slaughter of cattle originating from the dairy basin of Parnaíba, Piauí, Brazil, as also the lesions in kidney, lung, liver, uterus, ovary and placenta (histopathology and immunohistochemistry). In the MAT, Hardjo was the predominant serovar with the highest number of reagent animals for the strain Hardjobovis/Sponselee. Anti-leptospiral antigens were scored in epithelial cells, interstitial vascular endothelium, endothelium of glomerular capillaries and Bowman's capsule of 20 positive animals. Inflammatory cells were more common in the kidney. PCR was positive in urine and kidney tissue

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study aimed to evaluate the interference of tuberculin test on the gamma-interferon (INFg) assay, to estimate the sensitivity and specificity of the INFg assay in Brazilian conditions, and to simulate multiple testing using the comparative tuberculin test and the INFg assay. Three hundred-fifty cattle from two TB-free and two TB-infected herds were submitted to the comparative tuberculin test and the INFg assay. The comparative tuberculin test was performed using avian and bovine PPD. The INFg assay was performed by the BovigamTM kit (CSL Veterinary, Australia), according to the manufacturer's specifications. Sensitivity and specificity of the INFg assay were assessed by a Bayesian latent class model. These diagnostic parameters were also estimate for multiple testing. The results of INFg assay on D0 and D3 after the comparative tuberculin test were compared by the McNemar's test and kappa statistics. Results of mean optical density from INFg assay on both days were similar. Sensitivity and specificity of the INFg assay showed results varying (95% confidence intervals) from 72 to 100% and 74 to 100% respectively. Sensitivity of parallel testing was over 97.5%, while specificity of serial testing was over 99.7%. The INFg assay proved to be a very useful diagnostic method.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Conidiobolomycosis is a granulomatous disease caused by the fungus Conidiobolus spp. in humans and animals. Traditional technique for diagnosis of the disease is isolation of the agent associated with the presence of typical clinical signs and pathological conditions. The aim of this study was to describe the development of a specific polymerase chain reaction (PCR) test for Conidiobolus lamprauges to detect the fungus in clinical samples. Samples from suspected animals were collected and submitted to isolation, histopathological analysis and amplification by PCR. DNA from tissues was subjected to PCR with fungi universal primers 18S rDNA gene, and specific primers were designed based on the same gene in C. lamprauges that generated products of about 540 bp and 222 bp respectively. The culture was positive in 26.6% of clinical samples. The PCR technique for C. lamprauges showed amplification of DNA from fresh tissues (80%) and paraffin sections (44.4%). In conclusion, the PCR technique described here demonstrated a high sensitivity and specificity for detection of fungal DNA in tissue samples, providing a tool for the rapid diagnosis of C. lamprauges.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The rickettsia Anaplasma marginale is considered the main agent of bovine anaplasmosis. Due the nonspecific clinical signs of the anaplasmosis, the diagnosis of infection depends of laboratory confirmation. In recent years, molecular diagnostic methods have been used to detect A. marginale in cattle. However, the existence of a large number of assays of different sensitivity and cost makes the choice of an appropriate test difficult. In the present study, a real-time Polymerase Chain Reaction (PCR) based on the msp5 target gene was quantitatively assessed and compared to an end point PCR. Both reactions were subjected to sensitivity and specificity evaluation using plasmid DNA and samples from cattle experimentally infected with A. marginale. A comparative field trial of the tests was carried out using samples of cattle from a stable enzootic area for A. marginale. The real-time PCR showed a higher sensitivity than the end point PCR. This reaction (i.e. real-time PCR) was able to detect one copy of the msp5 gene in 100 ηg of plasmidial DNA, and more than 80% of its results were positive among experimentally infected animals seven days after infection. In addition, based on in silico analysis, the real-time PCR evaluated in the present study appears to be useful for the detection of A. ovis.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Visceral leishmaniasis is a chronic infectious disease caused by Leishmania infantum (synonym: Leishmania chagasi) and transmitted by the sandfly Lutzomyia longipalpis in Brazil. It is an endemic zoonosis in several regions of the country, including Belo Horizonte (State of Minas Gerais). In urban areas, the domestic dog is susceptible and considered the most important animal reservoir. However, L. infantum has been previously diagnosed in other species, including captive primates and canids. This study aimed to evaluate the presence of the agent DNA in captive animals as well as some free ranging animals from the Zoo-Botanical Foundation of Belo Horizonte by Polymerase Chain Reaction. Eighty one blood samples from primates, carnivores, ruminants, edentates, marsupial, and a monogastric herbivore were analyzed. Three primates Alouatta guariba (brown howler monkey), and two canids Speothos venaticus (bush dog) were positive, demonstrating the importance of leishmaniasis control in endemic areas for preservation of wildlife species in captivity.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In recent years haemosporidian infection by protozoa of the genus Plasmodium and Haemoproteus, has been considered one of the most important factors related to the extinction and/or population decline of several species of birds worldwide. In Brazil, despite the large avian biodiversity, few studies have been designed to detect this infection, especially among wild birds in captivity. Thus, the objective of this study was to analyze the prevalence of Plasmodium spp. and Haemoproteus spp. infection in wild birds in captivity in the Atlantic Forest of southeastern Brazil using microscopy and the polymerase chain reaction. Blood samples of 119 different species of birds kept in captivity at IBAMA during the period of July 2011 to July 2012 were collected. The parasite density was determined based only on readings of blood smears by light microscopy. The mean prevalence of Plasmodium spp. and Haemoproteus spp. infection obtained through the microscopic examination of blood smears and PCR were similar (83.19% and 81.3%, respectively), with Caracara plancus and Saltator similis being the most parasitized. The mean parasitemia determined by the microscopic counting of evolutionary forms of Plasmodium spp. and Haemoproteus spp. was 1.51%. The results obtained from this study reinforce the importance of the handling of captive birds, especially when they will be reintroduced into the wild.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The melanocortin system is an important regulator of feeding, energy metabolism,and cardiovascular function and it consists of the pro-opiomelanocortin (POMC) derived melanocyte stimulating hormones (α-, β- and γ-MSH) and their endogenous melanocortin receptors, MC1R to MC5R. In the hypothalamus, α-MSH reduces food intake, and increases energy expenditure and sympathetic tone by binding to MC4R. Mutations affecting the MC4R gene lead to obesity in mammals. On the other hand, the metabolic effects of MC3R stimulation using agonists such as the endogenously expressed γ-MSH have been less extensively explored. The main objective of this study was to investigate the long-term effects of increased melanocortin tone in key areas of metabolic regulation in the central nervous system (CNS) in order to investigate the sitespecific roles of both α-MSH and γ-MSH. The aim was to stereotaxically induce local overexpression of single melanocortin peptides using lentiviral vectors expressing α-MSH (LVi-α-MSH-EGFP) and γ-MSH (LVi-γ-MSH-EGFP). The lentiviral vectors were shown to produce a long-term overexpression and biologically active peptides in cell-based assays. The LVi-α-MSHEGFP was targeted to the arcuate nucleus in the hypothalamus of diet induced obese mice where it reduced weight gain and adiposity independently of food intake. When the nucleus tractus solitarus in the brainstem was targeted, the LVi-α-MSH-EGFP treatment was shown to cause a small decrease in adiposity, which did not impact weight development. However, the α-MSH treatment increased heart rate, which was attenuated by adrenergic receptor blockade indicative of increased sympathetic activity. The LVi-γ-MSH-EGFP was targeted to the hypothalamus where it decreased fat mass in mice eating the standard diet, but the effect was abated if animals consumed a high-fat Western type diet. When the diet induced obese mice were subjected again to the standard diet, the LVi-γ-MSH-EGFP treated animals displayed increased weight loss and reduced adiposity. These results indicate that the long-term central anti-obesity effects of α-MSH are independent of food intake. In addition, overexpression of α-MSH in the brain stem efficiently blocked the development of adiposity, but increased sympathetic tone. The evidence presented in this thesis also indicates that selective MC3R agonists such as γ-MSH could be potential therapeutics in combination with low fat diets.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Context: BL Lacs are the most numerous extragalactic objects which are detected in Very High Energy (VHE) gamma-rays band. They are a subclass of blazars. Large flux variability amplitude, sometimes happens in very short time scale, is a common characteristic of them. Significant optical polarization is another main characteristics of BL Lacs. BL Lacs' spectra have a continuous and featureless Spectral Energy Distribution (SED) which have two peaks. Among 1442 BL Lacs in the Roma-BZB catalogue, only 51 are detected in VHE gamma-rays band. BL Lacs are most numerous (more than 50% of 514 objects) objects among the sources that are detected above 10 GeV by FERMI-LAT. Therefore, many BL Lacs are expected to be discovered in VHE gamma-rays band. However, due to the limitation on current and near future technology of Imaging Air Cherenkov Telescope, astronomers are forced to predict whether an object emits VHE gamma-rays or not. Some VHE gamma-ray prediction methods are already introduced but still are not confirmed. Cross band correlations are the building blocks of introducing VHE gamma-rays prediction method. Aims: We will attempt to investigate cross band correlations between flux energy density, luminosity and spectral index of the sample. Also, we will check whether recently discovered MAGIC J2001+435 is a typical BL Lac. Methods: We select a sample of 42 TeV BL Lacs and collect 20 of their properties within five energy bands from literature and Tuorla blazar monitoring program database. All of the data are synchronized to be comparable to each other. Finally, we choose 55 pair of datasets for cross band correlations finding and investigating whether there is any correlation between each pair. For MAGIC J2001+435 we analyze the publicly available SWIFT-XRT data, and use the still unpublished VHE gamma-rays data from MAGIC collaboration. The results are compared to the other sources of the sample. Results: Low state luminosity of multiple detected VHE gamma-rays is strongly correlated luminosities in all other bands. However, the high state does not show such strong correlations. VHE gamma-rays single detected sources have similar behaviour to the low state of multiple detected ones. Finally, MAGIC J2001+435 is a typical TeV BL Lac. However, for some of the properties this source is located at the edge of the whole sample (e.g. in terms of X-rays flux). Keywords: BL Lac(s), Population study, Correlations finding, Multi wavelengths analysis, VHE gamma-rays, gamma-rays, X-rays, Optical, Radio

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Combined therapy with radiation and chemotherapy has being increasingly used in cancer treatment. The effect of combinations of taxol (0.08 mug/ml) with doxorubicin (DXR, 0.5 or 1.0 mug/ml) or gamma radiation (20 or 40 cGy) was examined in two different treatment schedules (pretreatment or simultaneous treatment) using Chinese hamster ovary (CHO) cells treated at the G2 phase of the cell cycle. The results showed that taxol did not have a radiosensitizing effect on the chromosomal aberrations induced by gamma radiation nor did it have a potentiating effect on the chromosomal aberrations induced by DXR in CHO cells treated in the G2 phase of the cell cycle