RESUMEN

Efforts to improve sea level forecasting on a warming planet have focused on determining the temperature, sea level and extent of polar ice sheets during Earth's past interglacial warm periods1-3. About 400,000 years ago, during the interglacial period known as Marine Isotopic Stage 11 (MIS11), the global temperature was 1 to 2 degrees Celsius greater2 and sea level was 6 to 13 metres higher1,3. Sea level estimates in excess of about 10 metres, however, have been discounted because these require a contribution from the East Antarctic Ice Sheet3, which has been argued to have remained stable for millions of years before and includes MIS114,5. Here we show how the evolution of 234U enrichment within the subglacial waters of East Antarctica recorded the ice sheet's response to MIS11 warming. Within the Wilkes Basin, subglacial chemical precipitates of opal and calcite record accumulation of 234U (the product of rock-water contact within an isolated subglacial reservoir) up to 20 times higher than that found in marine waters. The timescales of 234U enrichment place the inception of this reservoir at MIS11. Informed by the 234U cycling observed in the Laurentide Ice Sheet, where 234U accumulated during periods of ice stability6 and was flushed to global oceans in response to deglaciation7, we interpret our East Antarctic dataset to represent ice loss within the Wilkes Basin at MIS11. The 234U accumulation within the Wilkes Basin is also observed in the McMurdo Dry Valleys brines8-10, indicating11 that the brine originated beneath the adjacent East Antarctic Ice Sheet. The marine origin of brine salts10 and bacteria12 implies that MIS11 ice loss was coupled with marine flooding. Collectively, these data indicate that during one of the warmest Pleistocene interglacials, the ice sheet margin at the Wilkes Basin retreated to near the precipitate location, about 700 kilometres inland from the current position of the ice margin, which-assuming current ice volumes-would have contributed about 3 to 4 metres13 to global sea levels.

RESUMEN

Various attempts to develop a vaccine against infectious pancreatic necrosis virus (IPNV) have not yielded consistent results. Thus, at present, no commercial vaccine is available that can be used with confidence to immunize fry of salmon and trout. We generated a cDNA clone of the large genome segment A of an IPNV Sp strain and expressed all structural protein genes in insect cells and larvae using a baculovirus expression system. Green fluorescent protein was also coexpressed as a reporter molecule. High yields of IPNV proteins were obtained and the structural proteins self assembled to form virus-like particles (VLPs). We tested the immunogenicity of the putative VLP antigen in immersion vaccine experiments (two concentrations) in rainbow trout (Oncorhynchus mykiss) fry, and by intraperitoneal immunisation of Atlantic salmon (Salmo salar) pre-smolts using an oil adjuvant formulation. Rainbow trout were challenged by immersion using either the Sp or the VR-299 strain of IPNV two or three weeks post-vaccination, while Atlantic salmon were bath challenged with Sp strain after two months, after parr-smolt transformation. In the rainbow trout fry challenged two weeks post-immunization, cumulative mortality rates three weeks post challenge were 14 % in the fry that had received the highest dose versus 8 % in the control groups. No indication of protection was seen in repeated trials using a lower dose of antigen and challenge three weeks post-immunisation. The cumulative mortality rate of intraperitoneally immunised Atlantic salmon post-smolts four weeks post challenge was lower (56%) than in the control fish (77%), showing a dose-response pattern.

Asunto(s)

Infecciones por Birnaviridae/veterinaria , Enfermedades de los Peces/prevención & control , Expresión Génica , Genes Virales/genética , Virus de la Necrosis Pancreática Infecciosa/genética , Salmonidae , Vacunación/veterinaria , Proteínas Estructurales Virales/genética , Vacunas Virales/genética , Animales , Anticuerpos Antivirales/inmunología , Antígenos Virales/inmunología , Baculoviridae , Infecciones por Birnaviridae/prevención & control , Células Cultivadas , ADN Complementario/genética , Relación Dosis-Respuesta a Droga , Ensayo de Inmunoadsorción Enzimática , Enfermedades de los Peces/virología , Vectores Genéticos/genética , Vectores Genéticos/inmunología , Proteínas Fluorescentes Verdes/metabolismo , Inmunohistoquímica , Spodoptera , Transfección , Vacunación/métodos , Vacunas de Subunidad/genética , Virión/inmunología , Virión/metabolismo

RESUMEN

Chimeric virus-like particles (VLPs) of infectious bursal disease virus (IBDV) were produced by coinfecting Spodoptera frugiperda (Sf-9) insect cells with two recombinant baculoviruses, vIBD-7 and vEDLH-22. vIBD-7 encodes VP2, VP3, and VP4 of the IBDV structural proteins. vEDLH-22 encodes VP2 with five histidine residues at the carboxy-terminus (VP2H). Coinfection produced hybrid VLPs composed of VP2, VP2H, and VP3. The additional histidine residues on VP2H enabled the efficient purification of VLPs based on immobilized metal affinity chromatography (IMAC). These results demonstrated that the VLPs formed are comprised of chimeric subunits with attached affinity ligands, and further, that sufficient His5 ligand was available for binding to the IMAC metal-chelating resin. Additionally, these novel particles were fully characterized for antigenicity by a series of monoclonal antibodies, and appeared identical to the two wild-type IBDV strains contributing subunits to the chimeric VLP. IMAC purification provides a promising low-cost and simple scheme to purify VLPs as vaccines.

Asunto(s)

Cromatografía de Afinidad/métodos , Virus de la Enfermedad Infecciosa de la Bolsa/genética , Virus de la Enfermedad Infecciosa de la Bolsa/aislamiento & purificación , Spodoptera/virología , Proteínas Estructurales Virales/genética , Animales , Baculoviridae/genética , Ensayo de Inmunoadsorción Enzimática , Histidina , Metales , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Ultrafiltración/métodos , Proteínas Estructurales Virales/inmunología , Proteínas Estructurales Virales/aislamiento & purificación

RESUMEN

TOPIC: The evaluation and selection of standardized psychological instruments for research and clinical practice. PURPOSE: To present a systematic strategy to facilitate the instrument evaluation and selection process. SOURCES: Psychometric theory, published literature, and clinical-research experience. CONCLUSION: A careful instrument evaluation process informs the examiner, increases the likelihood that the best available instrument will be selected, and improves research and clinical practice by ensuring the integrity of standardized instruments.

Asunto(s)

Psiquiatría Infantil , Investigación en Enfermería Clínica/métodos , Enfermería Psiquiátrica , Escalas de Valoración Psiquiátrica/normas , Humanos , Psicometría , Reproducibilidad de los Resultados

RESUMEN

The VP2 structural gene encoded in the large genomic segment A of the variant GLS strain of infectious bursal disease virus (IBDV) was modified to encode a neutralization epitope (B69), found only on classic strains of IBDV. A chimeric cDNA clone of the large segment A, encoding VP3, VP4, and the modified variant IBDV VP2 structural proteins, was expressed in a recombinant baculovirus. The chimeric protein expressed was assessed with a panel of neutralizing monoclonal antibodies (MAbs), and it contained not only all previously MAb-defined GLS variant strain epitopes but also the B69 neutralization epitope found on classic IBDV strains. Complete active protection was afforded to specific-pathogen-free chickens by a subunit chimeric vaccine against virulent challenge with the classic IM and STC strains, as well as against the variant E/Del and GLS IBDV strains. Compared with a previously tested recombinant subunit vaccine, which incorporated unmodified baculovirus-expressed large-segment A GLS proteins, the recombinant chimeric subunit vaccine resulted in markedly improved active cross-protection against classic IBDV challenge.

Asunto(s)

Infecciones por Birnaviridae/veterinaria , Pollos/inmunología , Virus de la Enfermedad Infecciosa de la Bolsa/inmunología , Enfermedades de las Aves de Corral/prevención & control , Proteínas Recombinantes de Fusión/inmunología , Proteínas Estructurales Virales/inmunología , Vacunas Virales/inmunología , Animales , Baculoviridae/genética , Infecciones por Birnaviridae/inmunología , Infecciones por Birnaviridae/prevención & control , Pollos/virología , Reacciones Cruzadas , Regulación Viral de la Expresión Génica , Virus de la Enfermedad Infecciosa de la Bolsa/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Estructurales Virales/genética , Vacunas Virales/genética

RESUMEN

Infectious bursal disease virus (IBDV) is responsible for a highly immunosuppressive disease in young chickens which causes significant economic losses to the poultry industry worldwide. The structural protein genes (VP2, VP3 and VP4) of a variant IBDV strain (GLS) were expressed in insect cells using a baculovirus expression system. Susceptible chickens vaccinated with a single dose of the recombinant IBDV antigens were completely protected against challenge with two variant strains of IBDV (GLS and Delaware), and partially protected against the standard challenge strain (STC). A booster dose of the recombinant antigens induced higher levels of neutralizing antibodies and afforded complete protection against both variant and standard virus challenges. Specific-pathogen-free hens vaccinated with a single dose of the same subunit vaccine produced virus-neutralizing antibodies that were capable of passively protecting the progeny from infection with variant IBDV.

Asunto(s)

Anticuerpos Antivirales/biosíntesis , Infecciones por Birnaviridae/veterinaria , Pollos/inmunología , Vectores Genéticos , Inmunización Pasiva/veterinaria , Virus de la Enfermedad Infecciosa de la Bolsa/inmunología , Nucleopoliedrovirus/genética , Enfermedades de las Aves de Corral/prevención & control , Vacunación/veterinaria , Proteínas Estructurales Virales/inmunología , Vacunas Virales/inmunología , Animales , Anticuerpos Antivirales/inmunología , Antígenos Virales/inmunología , Infecciones por Birnaviridae/prevención & control , Bolsa de Fabricio/inmunología , Bolsa de Fabricio/microbiología , Virus de la Enfermedad Infecciosa de la Bolsa/clasificación , Virus de la Enfermedad Infecciosa de la Bolsa/genética , Virus de la Enfermedad Infecciosa de la Bolsa/aislamiento & purificación , Mariposas Nocturnas , Pruebas de Neutralización , Vacunas Sintéticas/inmunología

RESUMEN

Plasmids were prepared that contained cDNA segments of the large genomic segment A of infectious bursal disease virus (IBDV) strain GLS-5. The genes encoding the IBDV structural proteins (VP2, VP3 and VP4) were introduced into the baculovirus transfer vector pBlueBacI to obtain a recombinant baculovirus vIBD-7. When insect cells were infected with recombinant viruses, the result was synthesis of IBDV precursor proteins which were processed by the viral protease. The recombinant IBDV antigens were characterized by immunoprecipitation with monoclonal antibodies (MAbs) and polyclonal antiserum to IBDV, and by antigen-capture ELISA using a panel of IBDV-specific MAbs. The recombinant IBDV antigens closely resembled the native IBDV proteins and reacted with all the GLS-5 strain-specific neutralizing MAbs that recognize only conformational epitopes of IBDV. When susceptible chickens were inoculated with the recombinant IBDV antigens, virus-neutralizing antibodies were induced that conferred up to 79% protection against IBDV challenge.

Asunto(s)

Virus de la Enfermedad Infecciosa de la Bolsa/inmunología , Enfermedades de las Aves de Corral/prevención & control , Infecciones por Reoviridae/prevención & control , Vacunas Sintéticas/inmunología , Proteínas Estructurales Virales/inmunología , Animales , Formación de Anticuerpos , Baculoviridae/genética , Secuencia de Bases , Cápside/genética , Cápside/inmunología , Proteínas de la Cápside , Pollos , Vectores Genéticos/genética , Datos de Secuencia Molecular , Pruebas de Neutralización , Precursores de Proteínas/genética , Procesamiento Proteico-Postraduccional , Proteínas Recombinantes/inmunología , Proteínas Estructurales Virales/genética

RESUMEN

A recombinant baculovirus (vEHX) encoding rat hepatic microsomal epoxide hydrolase has been constructed. Infection of Spodoptera frugiperda (Sf9) cells with the recombinant virus results in the expression of the enzyme at a level estimated to be between 5% and 10% of the cellular protein. The enzyme, which can be purified in 15% yield by a simple three-step procedure involving detergent extraction, DEAE-cellulose chromatography, and removal of the detergent on hydroxylapatite, has physical and kinetic properties very close to those of the enzyme obtained from rat liver microsomes. The interaction of the enzyme with two nitrogen-containing analogues of the substrate phenanthrene 9,10-oxide (1) was investigated in order to delineate the contributions of the oxirane group and the hydrophobic surface of the substrate to substrate recognition. The enzyme exhibits altered kinetic properties toward 1,10-phenanthroline 5,6-oxide (2) in which the biphenyl group of 1 is replaced with a bipyridyl group, suggesting that hydrophobic interaction between the complementary surfaces of the substrate and active site has an influence on catalysis. The conjugate acid of the aziridine analogue of 1, phenanthrene 9,10-imine (3), in which the oxirane oxygen is replaced with NH, has a pKa of 6.1, which allows the characterization of both the neutral and protonated aziridine (3H+) as substrate analogues for the enzyme. The pH dependence of the solvolysis reveals that 3H+ rearranges to a 65/35 mixture of 9-aminophenanthrene and 9-amino-10-hydroxy-9,10-dihydrophenanthrene 10(3)-fold faster than does 3. The neutral aziridine is a competitive inhibitor (Ki = 26 microM) of the enzyme at pH 8.(ABSTRACT TRUNCATED AT 250 WORDS)

Asunto(s)

Epóxido Hidrolasas/metabolismo , Microsomas Hepáticos/enzimología , Fenantrenos/metabolismo , Fenantrolinas/metabolismo , Animales , Baculoviridae/genética , Línea Celular , Cromatografía , Cromatografía DEAE-Celulosa , Clonación Molecular , Durapatita , Electroforesis en Gel de Poliacrilamida , Epóxido Hidrolasas/genética , Epóxido Hidrolasas/aislamiento & purificación , Vectores Genéticos , Hidroxiapatitas , Insectos , Cinética , Matemática , Peso Molecular , Mariposas Nocturnas/genética , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Mapeo Restrictivo , Especificidad por Sustrato , Transfección

RESUMEN

We surveyed the whole blood selenium status of a randomly sampled population of horses from 4 contiguous counties in northern Maryland. Two hundred and two horses from 74 farms were sampled. Whole blood selenium levels greater than or equal to 0.100 parts per million (ppm) were considered adequate; blood levels less than 0.100 ppm were considered marginal or deficient. The average blood selenium concentration of the horses sampled was 0.137 ppm, with a standard deviation of 0.041 ppm. Blood selenium concentrations ranged from 0.050-0.266 ppm. Thirty-eight of 202 horses (18.8%) had a selenium level less than or equal to 0.099 ppm. Twenty-one of 74 farms (28.4%) had at least 1 horse with a selenium level less than or equal to 0.099 ppm. Animal husbandry practices had a significant influence on selenium status. Horses were more prone to having an abnormal selenium status if they were either maintained on pasture or used infrequently, or if their diet did not include mineral and vitamin supplements.

Asunto(s)

Crianza de Animales Domésticos , Caballos/sangre , Selenio/sangre , Alimentación Animal , Animales , Maryland

Asunto(s)

Minerales/análisis , Filtración , Métodos , Microscopía de Contraste de Fase , Estados Unidos , United States Public Health Service

Asunto(s)

Harina , Triticum , Fenómenos Químicos , Química