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1.
An Acad Bras Cienc ; 94(suppl 4): e20210445, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36449856

RESUMEN

From a standpoint of phytosociological research, little is known about the phytocoenosis found on the volcanoes of Central America. This paper analyses the distribution of the vegetation on the volcano of San Pedro in terms of its species-richness, composition, structure and abundance, and the possible relationships between these components and the changes in elevation and orientation that occur there. We divided the study area into three altitudinal belts between 2,400 and 3,020 m a.s.l. where carried out 36 inventories, each one in an area of 0.1 ha. We then applied multivariate analysis to classify and order the data in the matrix obtained from the frequency of the sampled plants. Our results lead us to propose two mixed cloud-forest associations within the class Alnetea acuminatae. The first, Saurauio oreophilae-Alnetum acuminatae ass. nova, is found on the more humid western side, while the second, Adianto andicolae-Quercetum peduncularis ass. nova, appears in sunnier and less shady sites, mainly on the east face. As part of this latter association, we also identified the new subassociation festucetosum amplissimae subass. nova. These syntaxa are part of the alliance Oreopanacion xalapensis all. nova, which we have created to embrace the mesophytic montane forests dominated by broad-leaved species.


Asunto(s)
Bosques , Registros , Guatemala , Análisis Multivariante
2.
J Environ Manage ; 300: 113748, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34543962

RESUMEN

Land-use/cover change is the major cause of terrestrial ecosystem degradation. However, its impacts will be exacerbated due to climate change and population growth, driving agricultural expansion because of higher demand of food and lower agricultural yields in some tropical areas. International strategies aimed to mitigate impacts of climate change and land use-cover change are challenging in developing regions. This study aims to evaluate alternatives to minimize the impacts of these threats under socioeconomic trajectories, in one of the biologically richest regions in Guatemala and Mexico. This study is located at the Usumacinta watershed, a transboundary region that shares a common history, with similar biophysical properties and economic constraints which have led to large land use/cover changes. To understand the impacts on deforestation and carbon emissions of different land-management practices, we developed three scenarios (1): business as usual (BAU), (2) a reducing emissions scenario aimed to reduce deforestation and degradation (REDD+), and (3) zero-deforestation from 2030 onwards based on the international commitments. Our results suggest that by 2050, natural land cover might reduce 22.3 and 12.2% of its extent under the BAU and REDD + scenarios, respectively in comparison with 2012. However, the zero-deforestation scenario shows that by 2050, it would be possible to avoid losing 22.4% of the forested watershed (1.7 million ha) and recover 5.9% (0.4 million hectares) of it. In terms of carbon sequestration, REDD + projects can reduce the carbon losses in natural vegetation, but a zero-deforestation policy can double the carbon sequestration produced by REDD + projects only. This study shows that to reduce the pressures on ecosystems, particularly in regions highly marginalized with significant migration, it is necessary to implement transboundary land-management policies that also integrate poverty alleviation strategies.


Asunto(s)
Cambio Climático , Ecosistema , Agricultura , Conservación de los Recursos Naturales , Bosques
3.
Sensors (Basel) ; 20(12)2020 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-32575690

RESUMEN

In solar thermal plants, the use of molten salt as a heat transfer fluid is an advantageous alternative, although it has some disadvantages such as the formation of salt plugs in the pipes due to possible stratification of the salt or its solidification. The aim of this study was to implement an electromagnetic acoustic transducer (EMAT) not only capable of identifying the position of the plug, but also of determining whether the plug blocks the entire conductive surface or, on the contrary, is partial, allowing the fluid to pass through a smaller section. The proposed transducer is intended to be minimally invasive, allowing it to be used in the same way as a temperature probe. To do so, it creates torsional waves in the pipe, which are then used for a combination of measurements: pulse-echo and attenuation of the acoustic waves. Two materials with different densities (silicone and cement) were used in the tests carried out, which made it possible to check that for a given size of blockage, it is possible to identify the type of material from which it is formed.

4.
Sensors (Basel) ; 19(11)2019 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-31181860

RESUMEN

A very interesting and useful complement to classical cash-registers is presented in this paper, coming up with a real-time auto-counting solution for the money inside a cash drawer. The system allows knowing not only the total amount of money but also how many coins and banknotes there are of each value. The embedded solution developed has been intended to become a low-cost solution, allowing better control over the money and helping both owners and workers in the establishments. By using this system, new utilities including automatic final balancing, instant error handling when making operations, and the lack of certain types of banknotes or coins inside the drawer or the excess of some in a certain compartment, could be implemented. Coins-counting solution is based on their weight, and small individual scales made by load cells have been integrated in each coin compartment. With respect to the banknotes, an innovative alternative based on the electrical properties of capacitors is presented. Additionally, considering the relevance of interoperability in today's systems, a Bluetooth module has been integrated into the system, allowing for data to be accessed remotely from any smartphone, tablet or computer within the range of the module. In this work, an Android application to both control and interact with the system has also been designed.

5.
Sensors (Basel) ; 19(10)2019 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-31137648

RESUMEN

The use of solar thermal power plants is considered a cost-effective alternative to produce renewable energy. Unlike other energy installations, in this type of plants the transfer and storage of energy has been solved by using molten salts. These salts run between two tanks through the steam generation system that feeds the turbine. Although the use of salts as a heat transfer fluid is considered an adequate solution, they are not without problems. One of them is the formation of blockages in the pipes due to a partial solidification of the salt, which leads to the shutdown of the installation, with the consequent economic losses. Fast location of these blockages in a minimally intrusive way is the objective pursued in this work. The method to achieve this is based on the use of a new magnetostrictive sensor that simplifies previous designs.

6.
J Gen Virol ; 96(Pt 6): 1340-1346, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25667323

RESUMEN

Infectious bronchitis virus (IBV) is a coronavirus of chickens that causes great economic losses to the global poultry industry. The present study focuses on South American IBVs and their genetic relationships with global strains. We obtained full-length sequences of the S1 coding region and N gene of IBV field isolates from Uruguay and Argentina, and performed Phylodynamic analysis to characterize the strains and estimate the time of the most recent common ancestor. We identified two major South American genotypes, which were here denoted South America I (SAI) and Asia/South America II (A/SAII). The SAI genotype is an exclusive South American lineage that emerged in the 1960s. The A/SAII genotype may have emerged in Asia in approximately 1995 before being introduced into South America. Both SAI and A/SAII genotype strains clearly differ from the Massachusetts strains that are included in the vaccine formulations being used in most South American countries.


Asunto(s)
Infecciones por Coronavirus/veterinaria , Variación Genética , Virus de la Bronquitis Infecciosa/clasificación , Proteínas de la Nucleocápside/genética , Enfermedades de las Aves de Corral/epidemiología , Enfermedades de las Aves de Corral/virología , Glicoproteína de la Espiga del Coronavirus/genética , Animales , Argentina/epidemiología , Pollos , Análisis por Conglomerados , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/virología , Proteínas de la Nucleocápside de Coronavirus , Genotipo , Virus de la Bronquitis Infecciosa/genética , Virus de la Bronquitis Infecciosa/aislamiento & purificación , Epidemiología Molecular , Datos de Secuencia Molecular , Filogenia , Análisis de Secuencia de ADN , Uruguay/epidemiología
7.
Avian Pathol ; 44(3): 212-21, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25746415

RESUMEN

Infectious bursal disease virus (IBDV) is one of the most concerning health problems for world poultry production. IBDVs comprise four well-defined evolutionary lineages known as classic (c), classic attenuated (ca), variant (va) and very virulent (vv) strains. Here, we characterized IBDVs from South America by the genetic analysis of both segments of the viral genome. Viruses belonging to c, ca and vv strains were unambiguously classified by the presence of molecular markers and phylogenetic analysis of the hypervariable region of the vp2 gene. Notably, the majority of the characterized viruses (9 out of 15) could not be accurately assigned to any of the previously described strains and were then denoted as distinct (d) IBDVs. These dIBDVs constitute an independent evolutionary lineage that also comprises field IBDVs from America, Europe and Asia. The hypervariable VP2 sequence of dIBDVs has a unique and conserved molecular signature (272T, 289P, 290I and 296F) that is a diagnostic character for classification. A discriminant analysis of principal components (DAPC) also identified the dIBDVs as a cluster of genetically related viruses separated from the typical strains. DAPC and genetic distance estimation indicated that the dIBDVs are one of the most genetically divergent IBDV lineages. The vp1 gene of the dIBDVs has non-vvIBDV markers and unique nucleotide and amino acid features that support their divergence in both genomic segments. The present study suggests that the dIBDVs comprise a neglected, highly divergent lineage that has been circulating in world poultry production since the early time of IBDV emergence.


Asunto(s)
Infecciones por Birnaviridae/genética , Evolución Molecular , Genoma Viral/genética , Virus de la Enfermedad Infecciosa de la Bolsa/genética , Enfermedades de las Aves de Corral/virología , Animales , Secuencia de Bases , Análisis Discriminante , Virus de la Enfermedad Infecciosa de la Bolsa/clasificación , Modelos Genéticos , Datos de Secuencia Molecular , Aves de Corral , Análisis de Componente Principal , Análisis de Secuencia de ADN/veterinaria , América del Sur , Especificidad de la Especie , Proteínas Estructurales Virales/genética
8.
Sensors (Basel) ; 14(2): 2379-96, 2014 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-24487622

RESUMEN

With photovoltaic (PV) systems proliferating in the last few years due to the high prices of fossil fuels and pollution issues, among others, it is extremely important to monitor the efficiency of these plants and optimize the energy production process. This will also result in improvements related to the maintenance and security of the installation. In order to do so, the main parameters in the plant must be continuously monitored so that the appropriate actions can be carried out. This monitoring should not only be carried out at a global level, but also at panel-level, so that a better understanding of what is actually happening in the PV plant can be obtained. This paper presents a system based on a wireless sensor network (WSN) that includes all the components required for such monitoring as well as a power supply obtaining the energy required by the sensors from the photovoltaic panels. The system proposed succeeds in identifying all the nodes in the network and provides real-time monitoring while tracking efficiency, features, failures and weaknesses from a single cell up to the whole infrastructure. Thus, the decision-making process is simplified, which contributes to reducing failures, wastes and, consequently, costs.

9.
Avian Dis ; 55(3): 368-74, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22017032

RESUMEN

Three types of infectious bursal disease virus (IBDV) strains are currently circulating worldwide: the low-pathogenic classic and variant strains and the high-pathogenic very virulent strains. There are also natural reassortant viruses that combine genomic segments A and B from different strains and exhibit particular pathogenic characteristics. Detection and characterization of the different IBDVs is extremely critical for improving disease control and performing epidemiologic studies. Here, we present a novel detection and genotyping method based on the simultaneous characterization of both IBDV genomic segments followed by a simple restriction fragment length polymorphism (RFLP) assay. This single restriction enzyme, multiplex reverse transcriptase-PCR/RFLP diagnostic test not only distinguished typical high-pathogenic from low-pathogenic strains but also detected natural reassortant IBDV. The test was based on the detection of single nucleotide polymorphisms (SNP), in both segments, which were strongly linked to the pathogenic phenotype. These SNPs are embedded in highly conserved genomic regions and can be identified with TfiI endonuclease. The application of this methodology in field samples confirmed that the assay is fast, specific, and may be easily adopted by any molecular diagnostic laboratory as an economical and routine method.


Asunto(s)
Infecciones por Birnaviridae/veterinaria , Bolsa de Fabricio/virología , Virus de la Enfermedad Infecciosa de la Bolsa/genética , Enfermedades de las Aves de Corral/diagnóstico , Animales , Secuencia de Bases , Infecciones por Birnaviridae/diagnóstico , Infecciones por Birnaviridae/epidemiología , Infecciones por Birnaviridae/virología , Pollos , Desoxirribonucleasas de Localización Especificada Tipo II/genética , Genotipo , Virus de la Enfermedad Infecciosa de la Bolsa/clasificación , Virus de la Enfermedad Infecciosa de la Bolsa/aislamiento & purificación , Polimorfismo de Longitud del Fragmento de Restricción , Polimorfismo de Nucleótido Simple , Enfermedades de las Aves de Corral/epidemiología , Enfermedades de las Aves de Corral/virología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alineación de Secuencia
10.
Virus Genes ; 41(1): 59-66, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20437197

RESUMEN

The infectious bursal disease virus (IBDV; Birnaviridae family) constitutes one of the main threats to the poultry industry worldwide. Most of the progress in the molecular epidemiology of this virus has been achieved through the study of the coding region of the capsid protein VP2. Little research has been done regarding the molecular evolution and the epidemiological implications of genetic variability of other IBDV genome regions. In this article, the gene that codes the non-structural protein VP5 was analyzed. Although this protein is not essential for the virus replication, recent evidence indicates that it could be related to the virulent phenotype and the adaptive capacity of the virus. The VP5 gene is also of evolutionary interest because it has an open reading frame that terminally overlaps with the pVP2-VP4-VP3 polyprotein coding region. In the first part of this study, the full VP5 gene of a South American strain was characterized. The results revealed that the VP5 gene of Uruguayan hypervirulent IBDV strains (vvIBDV) lacks the alternative AUG start codon characteristic of the vvIBDV strains that have been described to date. Instead, as occurs in classic and variant strains, this VP5 gene has an AUG start site located four codons downstream and, consequently, it codes for a 145 amino acid long protein rather than the putative 149 amino acid long protein of other vvIBDV. In spite of this, these viruses conserved the VP5 and VP2 amino acid signature of the hypervirulent strains and clustered with reference vvIBDV sequences. This finding may represent evidence that the VP5 gene could be evolving by changing the translation initiation site. In the second part of this study, an evolutionary analysis including the sequences reported in this study together with most of VP5 sequences available in the GenBank, showed the existence of a complex system of selective pressures controlling the evolution of the VP5 gene. Using the dN/dS index, we found a strong purifying selection exerted on the 5' terminal overlapping region of VP2 that would be constraining the evolution of VP5. These results reinforce the hypothesis that the VP5 gene was originated late in the IBDV evolution by a mechanism of genetic overprinting. The results described in this study provided new information about the dynamics of the IBDV genome and revealed some of the mechanisms at play in the evolution of this virus. Since VP5 seems to be related to viral pathogenicity, this evolutionary information might be useful to highlight the impact of the genetic variation of this protein on the epidemiology of IBDV.


Asunto(s)
Evolución Molecular , Virus de la Enfermedad Infecciosa de la Bolsa/genética , Proteínas no Estructurales Virales/genética , Secuencia de Aminoácidos , Secuencia de Bases , Infecciones por Birnaviridae/virología , Genoma Viral , Humanos , Virus de la Enfermedad Infecciosa de la Bolsa/química , Virus de la Enfermedad Infecciosa de la Bolsa/aislamiento & purificación , Datos de Secuencia Molecular , Filogenia , Alineación de Secuencia , Uruguay , Proteínas no Estructurales Virales/química
11.
Avian Pathol ; 37(3): 237-45, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18568649

RESUMEN

The Villegas-Glisson/University of Georgia (VG/GA) strain of Newcastle disease virus (NDV) isolated from the intestine of healthy turkeys has been proposed to replicate in the respiratory and intestinal tract of chickens. In the present study, the virus distribution, the mucosal and systemic immune response, the efficacy against lethal challenge and the full genome sequence of the VG/GA strain were compared with the La Sota strain of NDV. The VG/GA strain was detected at different time points in the respiratory and intestinal tract of chickens with a preferential tropism for the latter. Both the VG/GA and La Sota strains induced NDV-specific immunoglobulin A (IgA) at the upper respiratory tract. IgA levels were higher in the trachea for the La Sota strain, while they were higher in the bile and intestine for the VG/GA strain. Positive correlation between virus distribution of the viruses and IgA production was observed. Despite the presence of the maternal antibodies in broilers, early vaccination with the VG/GA strain afforded 95% to 100% protection against lethal challenge, equivalent to the protection conferred by the La Sota strain. Full genome sequence analysis classified the VG/GA strain within class II, genotype II viruses, which also include most of the respirotropic vaccine strains. Differences with the La Sota strain at the nucleotide and amino acid levels that may explain the differential phenotype of the VG/GA were observed; however, verification of the significance of those changes is required. Taken together, these results validate field observations on the efficacy of VG/GA vaccination and demonstrated the unique characteristics of the strain.


Asunto(s)
Pollos , Inmunidad Mucosa/inmunología , Enfermedad de Newcastle/virología , Virus de la Enfermedad de Newcastle/clasificación , Vacunas Virales/inmunología , Sustitución de Aminoácidos , Animales , Anticuerpos Antivirales , Inmunoglobulina A/sangre , Inmunoglobulina G/sangre , Intestinos/virología , Enfermedad de Newcastle/prevención & control , Virus de la Enfermedad de Newcastle/genética , Filogenia , Sistema Respiratorio/virología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Organismos Libres de Patógenos Específicos , Proteínas Virales/química , Proteínas Virales/genética
12.
Avian Dis ; 52(4): 670-4, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19166061

RESUMEN

Infectious bursal disease virus (IBDV) is the causative agent of infectious bursal disease, a nosologic entity with global economic importance in poultry. The viral protein 2 (VP2) is recognized as the virus' major antigenic protein. The goal of this study was to generate yeast (Pichia pastoris)-based protein expression from the VP2 gene of the Edgar strain of IBDV and from the hypervariable region of the VP2 gene (hvVP2) to test the protection afforded against virulent IBDV challenge when inoculated in chickens. The genetic material used for protein expression was obtained from paraffin-embedded tissue. Specific-pathogen-free chickens were vaccinated with the expressed products and challenged with the homologous strain (Edgar). After challenge, no morbidity or mortality was observed in the birds vaccinated with the whole VP2, compared with 30% morbidity and mortality in the hvVP2-vaccinated birds and with 90% morbidity and 60% mortality in the unvaccinated, challenged controls. Immunohistochemistry detection of the challenge virus and some extent of bursal damage were observed in all challenged birds, indicating active replication of the challenge virus despite vaccination. As determined by bursal index values, the protection against postchallenge bursal atrophy was significantly higher (P < 0.05) in the VP2 group than in the unvaccinated and hvVP2-vaccinated birds. Overall, the results indicated that paraffin-embedded tissue can be used as a source of genomic material for transgenic protein expression, that Pichia pastoris-expressed VP2 retains its immunogenicity, and that VP2 subunit vaccination conferred partial protection to challenge; it protected against clinical signs and death but not against IBDV infection.


Asunto(s)
Infecciones por Birnaviridae/veterinaria , Pollos , Virus de la Enfermedad Infecciosa de la Bolsa/inmunología , Enfermedades de las Aves de Corral/prevención & control , Proteínas Estructurales Virales/inmunología , Vacunas Virales , Animales , Infecciones por Birnaviridae/prevención & control , Virus de la Enfermedad Infecciosa de la Bolsa/genética , Subunidades de Proteína/inmunología , Organismos Libres de Patógenos Específicos , Vacunación/veterinaria , Vacunas de Subunidad , Proteínas Estructurales Virales/química , Proteínas Estructurales Virales/genética
13.
Avian Dis ; 52(2): 297-301, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18646460

RESUMEN

The efficacy of coarse spray vaccination against pathogenic infectious bursal disease virus (IBDV) in commercial broilers was evaluated. Different coarse spray vaccination schedules using a commercial 2512 strain vaccine were compared with single or double drinking water application at 1 and/or 10 days of age. At 29 days of age, the chickens were challenged with the virulent Edgar strain of IBDV. Seven days postchallenge, severe gross bursal atrophy was observed in the unvaccinated-challenged birds. After challenge and regardless of the method of vaccination used, moderate-to-severe lymphoid depletion was observed, indicating challenge virus replication, later confirmed by reverse transcriptase-polymerase chain reaction and restriction fragment length polymorphism analysis. Coarse spray and drinking water vaccination induced protection against body weight loss. Significant differences (P < 0.05) were observed between the unvaccinated-challenged group (1483 g) and the birds vaccinated at 10 days of age by coarse spray (1812 g). The coarse spray vaccination also induced protection against challenge-induced gross bursal atrophy, as determined by bursal index values. After challenge, significant bursal atrophy was observed in the birds orally vaccinated at 1 day (0.61), 10 days (0.66), and 1 and 10 days (0.63) as well as the unvaccinated-challenged birds (0.62), but not in the coarse-spray-vaccinated groups that exhibited bursal indexes above 0.70 and did not differ from the unvaccinated-unchallenged control group. These results suggest that coarse spray vaccination can be considered as another tool to control IBDV in the field.


Asunto(s)
Infecciones por Birnaviridae/veterinaria , Virus de la Enfermedad Infecciosa de la Bolsa/inmunología , Enfermedades de las Aves de Corral/prevención & control , Vacunación/veterinaria , Vacunas Virales/administración & dosificación , Administración Oral , Aerosoles , Animales , Anticuerpos Antivirales/sangre , Infecciones por Birnaviridae/inmunología , Infecciones por Birnaviridae/patología , Infecciones por Birnaviridae/prevención & control , Bolsa de Fabricio/patología , Pollos , Virus de la Enfermedad Infecciosa de la Bolsa/genética , Virus de la Enfermedad Infecciosa de la Bolsa/aislamiento & purificación , Virus de la Enfermedad Infecciosa de la Bolsa/patogenicidad , Polimorfismo de Longitud del Fragmento de Restricción , Enfermedades de las Aves de Corral/inmunología , Enfermedades de las Aves de Corral/patología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Vacunación/métodos
14.
Avian Dis ; 52(4): 558-66, 2008 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-19166045

RESUMEN

Pathogens of free-ranging chickens create a risk of disease for wild birds, some of which migrate to the United States, as well as potential economic losses for resource-poor farmers. Free-roaming backyard chickens are commonly kept in shade-grown coffee plantations, habitats that attract large numbers of wild birds. The husbandry and pathogen prevalence of backyard chicken flocks in San Luis, Costa Rica, were investigated. Based on serologic evidence, Newcastle disease virus, infectious laryngotracheitis virus, infectious bronchitis virus, chicken anemia virus, and infectious bursal disease virus, as well as both Mycoplasma gallisepticum and Mycoplasma synoviae, appear to be significant diseases of this population, and thus, we consider these backyard chickens potential reservoirs for these diseases. There was no evidence of avian influenza. Interviews, clinical examinations, and microscopic examination of tissues led us to believe that poxvirus is also a significant cause of morbidity and mortality in these chickens. We found that Escherichia coli isolates were resistant against tilmicosin, tetracycline, ampicillin, amoxicillin with clavulanic acid, ticarcillin, and cephalothin, and contained genes considered responsible for conferring tetracycline resistance. Additionally, although production was not measured, we suspect that husbandry and lack of preventative medicine are directly related to the diseases reported, all of which negatively affect production.


Asunto(s)
Pollos , Enfermedades de las Aves de Corral/transmisión , Agricultura , Crianza de Animales Domésticos , Animales , Animales Salvajes , Anticuerpos Antibacterianos/sangre , Anticuerpos Antivirales/sangre , Infecciones Bacterianas/epidemiología , Infecciones Bacterianas/microbiología , Costa Rica/epidemiología , Enfermedades de las Aves de Corral/epidemiología , Enfermedades de las Aves de Corral/microbiología , Factores de Riesgo , Virosis/epidemiología , Virosis/virología
15.
Virus Res ; 124(1-2): 68-77, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17098316

RESUMEN

Reticuloendotheliosis virus (REV) causes runting, high mortality, immunosuppression, and chronic neoplasia associated with T and/or B cell lymphomas in a variety of domestic and wild birds, including Attwater's prairie chickens (APC) (Tympanuchus cupido attwateri). The complete proviral sequence of a recent REV isolate from APC (REV APC-566) was determined. This virus was isolated from an APC maintained in captivity in a reproduction program intended to avoid its extinction. REV APC-566 was determined to be oncogenic in Japanese quail (Coturnix coturnix japonica), chickens (Gallus gallus) and turkeys (Meleagris gallopavo). Immune responses against bacteria and viruses were significantly reduced in turkeys infected with REV APC-566. The proviral genome is 8286 nucleotides in length and exhibits a genetic organization characteristic of replication-competent gammaretroviruses. The REV APC-566 provirus contains two identical long terminal repeats (LTR) and a complete set of genes including gag, gag-pol and env. As previously reported, alignments with other REV sequences showed high similarity with sequences found in the gag and pol genes from other REVs. The REV APC-566 env gene showed high nucleotide sequence homology with REV sequences inserted in fowl poxvirus (99.8%), and with spleen necrosis virus (SNV) (95.1%). Sequences coding for a previously reported immunosuppressive peptide contained in the transmembrane region of the env gene are well conserved among all REV sequences analyzed. The LTR was the most divergent region, exhibiting various deletions and insertions. REV APC-566 has a unique insertion of 23 bp in U3 and shares deletions of 19 and 5 bp with chicken syncytial virus and REV inserts in fowlpox virus.


Asunto(s)
Enfermedades de las Aves/virología , Galliformes , Genoma Viral , Virus de la Reticuloendoteliosis/genética , Infecciones por Retroviridae/veterinaria , Infecciones Tumorales por Virus/veterinaria , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Infecciones por Birnaviridae/inmunología , Infecciones por Birnaviridae/veterinaria , Virus de la Viruela de las Aves de Corral/genética , Virus de la Enfermedad Infecciosa de la Bolsa/inmunología , Datos de Secuencia Molecular , Infecciones por Pasteurella/inmunología , Infecciones por Pasteurella/mortalidad , Infecciones por Pasteurella/veterinaria , Pasteurella multocida/inmunología , Recombinación Genética , Virus de la Reticuloendoteliosis/inmunología , Virus de la Reticuloendoteliosis/aislamiento & purificación , Infecciones por Retroviridae/virología , Proteínas de los Retroviridae/genética , Alineación de Secuencia , Homología de Secuencia de Ácido Nucleico , Secuencias Repetidas Terminales/genética , Virus de la Necrosis Esplénica del Pato de Trager/genética , Infecciones Tumorales por Virus/virología , Pavos/inmunología
16.
J Vet Diagn Invest ; 19(1): 35-42, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17459830

RESUMEN

Formalin fixed paraffin embedded tissues blocks are used routinely to diagnose the economically important immunosuppressive infectious bursal disease virus (IBDV) in chickens. Immunohistochemical detection of viruses in tissue blocks has been done with varying results between laboratories. Extraction of IBDV RNA from tissue blocks allows IBDV strain identification at a molecular level. This allows correlation between virus identity and histological lesions present in the tissue. Experimentally reverse transcription-polymerase chain reaction (RT-PCR) detectable IBDV RNA could always be extracted from tissue blocks with acute +3 or higher histological lesion scores. However, many blocks from diagnostic field cases did not yield detectable IBDV RNA, in spite of having severe IBDV histological lesion scores. The reason for this can be the effect different formalin fixation conditions have on RNA detection from tissue blocks. To study the effect of various fixation parameters on RNA extraction and immunohistochemical detection of IBDV, bursas with maximum histological lesion score of 4 for IBDV were fixed in formalin under various conditions (different pH levels, temperatures, concentrations of formalin, and fixation duration). Only tissues fixed in formalin with a pH of 7.0, concentration of 5 or 10% formaldehyde, storage temperature of 25 degrees C or less, and kept for up to 2 weeks in formalin yielded detectable IBDV RNA upon extraction. No RNA could be detected from tissues fixed under extreme temperature, pH, or formalin concentrations. Optimal fixation conditions for IHC detection of IBDV were 10% formalin concentration, pH 7.0, and temperature of 4 degrees C, where maximum intensity of immunostaining was observed.


Asunto(s)
Infecciones por Birnaviridae/veterinaria , Pollos/virología , Virus de la Enfermedad Infecciosa de la Bolsa/aislamiento & purificación , Adhesión en Parafina , Enfermedades de las Aves de Corral/diagnóstico , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Animales , Infecciones por Birnaviridae/diagnóstico , Infecciones por Birnaviridae/virología , Bolsa de Fabricio/patología , Formaldehído , Inmunohistoquímica , Enfermedades de las Aves de Corral/virología , ARN Viral/aislamiento & purificación , Organismos Libres de Patógenos Específicos , Temperatura , Fijación del Tejido
17.
Avian Dis ; 51(1): 33-9, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17461264

RESUMEN

The pathogenicity and transmission of a field isolate of reticuloendotheliosis virus (REV) was studied using an experimental model in Japanese quail. Oncogenicity was also evaluated after inoculations in chickens and turkeys. The original REV (designated APC-566) was isolated from Attwater's prairie chickens (Tympanuchus cupido attwateri), an endangered wild avian species of the southern United States. The transmissibility of the REV isolate was studied in young naive Japanese quail in contact with experimentally infected quail. Vertical transmission was not detected by virus isolation and indirect immunofluorescence. Seroconversion was detected in few contact quails, suggesting horizontal transmission. The APC-566 isolate induced tumors beginning at 6 wk of age in quails infected as embryos. Most of the tumors detected in Japanese quail were lymphosarcomas, and 81% of these neoplasias contained CD3+ cells by immunoperoxidase. REV APC-566 was also oncogenic in chickens and turkeys infected at 1 day of age, with tumors appearing as early as 58 days after infection in chickens and at 13 wk of age in turkeys. This study was conducted in part as an attempt to understand the potential for pathogenicity and transmission of REV isolated from endangered avian species.


Asunto(s)
Galliformes/virología , Enfermedades de las Aves de Corral/virología , Virus de la Reticuloendoteliosis Aviar/aislamiento & purificación , Virus de la Reticuloendoteliosis Aviar/patogenicidad , Infecciones por Retroviridae/veterinaria , Infecciones Tumorales por Virus/veterinaria , Animales , Enfermedades de las Aves de Corral/patología , Enfermedades de las Aves de Corral/transmisión , Infecciones por Retroviridae/patología , Infecciones por Retroviridae/transmisión , Infecciones por Retroviridae/virología , Infecciones Tumorales por Virus/patología , Infecciones Tumorales por Virus/transmisión , Infecciones Tumorales por Virus/virología , Viremia/veterinaria
18.
J Virol Methods ; 138(1-2): 66-9, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16978712

RESUMEN

Infectious bursal disease virus (IBDV) is an important poultry pathogen and is distributed world wide that can cause immune suppression and lesions of the bursa of Fabricius. The main component of the virus, VP2, is not only responsible for the bird's immune response, but is important for the molecular identification of this virus as well. The nucleic acid of the virus must be adequately preserved to be analyzed by reverse-transcriptase PCR (RT-PCR) and sequenced for the molecular characterization of the field strain. Phenol inactivation has been the standard for IBDV tissue collection and international shipment; however, there have been some reports of interference with molecular detection capabilities when using phenol. Phenol is also a hazardous chemical and must be handled and shipped carefully. The ability to use the Flinders Technology Associates filter paper (FTA card) for inactivation of several avian pathogens has been proven previously, however no work has been published on its use in IBDV nucleic acid detection. Bursas from experimentally infected birds was imprinted on FTA cards, and then placed in phenol. Samples were evaluated and compared based on molecular detection capabilities between the two inactivation methods. The nucleic acid of the virus was detected in 85% of the FTA card inactivated samples compared to 71% in the phenol inactivated samples. Sequence analysis was performed on samples inactivated by both methods and no differences were found. When comparing the RNA stability at different temperatures, euthanized IBDV infected birds were held at two different temperatures before sampling. No differences were detected for FTA sampling; however, for tissues in phenol the nucleic acid was only detectable up to 2 h post-mortem in the tissues held at 4 degrees C prior to sampling. These findings indicate that the FTA card is an efficient and reliable alternative collection method for molecular detection and characterization of IBDV.


Asunto(s)
Virus de la Enfermedad Infecciosa de la Bolsa/aislamiento & purificación , ARN Viral/aislamiento & purificación , Manejo de Especímenes/métodos , Inactivación de Virus , Animales , Infecciones por Birnaviridae/veterinaria , Infecciones por Birnaviridae/virología , Bolsa de Fabricio/virología , Pollos/virología , Virus de la Enfermedad Infecciosa de la Bolsa/genética , Fenol , ARN Viral/análisis , ARN Viral/genética
19.
Avian Dis ; 50(2): 216-21, 2006 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-16863070

RESUMEN

Recombinant avian adeno-associated viruses coding for the LacZ gene were used to inoculate embryonating chicken eggs, to assess the usefulness of the system for the expression of a transgene in vivo. The results obtained indicate significantly higher levels of expression of the reporter gene at various time intervals in the embryos inoculated with the recombinant virus in comparison with the mock-inoculated controls. At the embryo level, significant differences were evident at 120 hr postinoculation; hatched chicks showed transgene expression up to 14 days of age. In a second experiment, different cell-line cultures were transfected with plasmids encoding for a reporter gene flanked by the avian adeno-associated virus inverted terminal repeats (ITR), either alone or in the presence of the major nonstructural proteins of the virus (Rep 78/68) to assess the ability of these proteins and DNA elements to enhance gene expression. Results indicate that the inclusion of the viral ITR alone or during coexpression of the Rep proteins significantly enhances the expression of the transgene in all cell lines tested, as evidenced by the detection of the beta-galacrosidase protein through chemiluminescence reactions and staining of transfected monolayers.


Asunto(s)
Pollos/genética , Pollos/virología , Dependovirus/genética , Transgenes/genética , Animales , Línea Celular , Embrión de Pollo , Expresión Génica , Humanos , Operón Lac/genética , Organismos Modificados Genéticamente , beta-Galactosidasa/genética , beta-Galactosidasa/metabolismo
20.
Avian Dis ; 50(4): 476-82, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17274281

RESUMEN

After histopathologic screening of bursas of Fabricius for the presence of infectious bursal disease virus (IBDV) lesions, the hypervariable region of the VP2 gene for IBDV was extracted from formalin-fixed paraffin-embedded tissue blocks. With real-time reverse transcription-polymerase chain reaction (RT-PCR) and sequencing, IBDV was identified in 227 different blocks. The ability to identify the actual virus strain associated with the lesions observed microscopically in the bursa of Fabricius allowed for direct correlation between viral identity and lesions, which may help in designing vaccination strategies. Several new emerging viruses that do not group with other known IBDVs in phylogenetic tree analysis were identified, as well as a unique variant virus that had 63 nucleotides missing from its hypervariable region.


Asunto(s)
Infecciones por Birnaviridae/veterinaria , Bolsa de Fabricio/virología , Pollos/virología , Virus de la Enfermedad Infecciosa de la Bolsa/genética , Virus de la Enfermedad Infecciosa de la Bolsa/aislamiento & purificación , Adhesión en Parafina , ARN Viral/aislamiento & purificación , Animales , Infecciones por Birnaviridae/virología , Virus de la Enfermedad Infecciosa de la Bolsa/clasificación , Filogenia , Enfermedades de las Aves de Corral/virología , ARN Viral/genética
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