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Tungsten inert gas (TIG) welding is a well-established joining process and offers the user flexibility to weld a large range of materials. Ultra-thin turbine tipping is an important application for TIG welding that is exceptionally challenging due to the wide range of variables needed to accurately control the process: slope times, arc control, travel speed, etc. We offer new insight into weld pool characteristics, utilizing both on- and off-line measurements of weld tracks. High-resolution thermal imaging yields spatially and temporally resolved weld pool phase transitions coupled with post-weld photographs, which gives a novel perspective into the thermal history of a weld. Our imaging system is filtered to measure a 10 nm window at 950 nm and comprises a commercial Sigma lens to produce a near-infrared (NIR) camera. The measured near-infrared radiance is calibrated for temperature over the range of from 800 to 1350 °C.
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The Soil Moisture Active-Passive (SMAP) L-band microwave radiometer is a conical scanning instrument designed to measure soil moisture with 4% volumetric accuracy at 40-km spatial resolution. SMAP is NASA's first Earth Systematic Mission developed in response to its first Earth science decadal survey. Here, the design is reviewed and the results of its first year on orbit are presented. Unique features of the radiometer include a large 6-m rotating reflector, fully polarimetric radiometer receiver with internal calibration, and radio-frequency interference detection and filtering hardware. The radiometer electronics are thermally controlled to achieve good radiometric stability. Analyses of on-orbit results indicate that the electrical and thermal characteristics of the electronics and internal calibration sources are very stable and promote excellent gain stability. Radiometer NEDT < 1 K for 17-ms samples. The gain spectrum exhibits low noise at frequencies >1 MHz and 1/f noise rising at longer time scales fully captured by the internal calibration scheme. Results from sky observations and global swath imagery of all four Stokes antenna temperatures indicate that the instrument is operating as expected.
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BACKGROUND: Guidelines preferentially recommend noncalcium phosphate binders in adults with chronic kidney disease (CKD). We compare and rank phosphate-binder strategies for CKD. STUDY DESIGN: Network meta-analysis. SETTING & POPULATION: Adults with CKD. SELECTION CRITERIA FOR STUDIES: Randomized trials with allocation to phosphate binders. INTERVENTIONS: Sevelamer, lanthanum, iron, calcium, colestilan, bixalomer, nicotinic acid, and magnesium. OUTCOMES: The primary outcome was all-cause mortality. Additional outcomes were cardiovascular mortality, myocardial infarction, stroke, adverse events, serum phosphorus and calcium levels, and coronary artery calcification. RESULTS: 77 trials (12,562 participants) were included. Most (62 trials in 11,009 patients) studies were performed in a dialysis population. Trials were generally of short duration (median, 6 months) and had high risks of bias. All-cause mortality was ascertained in 20 studies during 86,744 patient-months of follow-up. There was no evidence that any drug class lowered mortality or cardiovascular events when compared to placebo. Compared to calcium, sevelamer reduced all-cause mortality (OR, 0.39; 95% CI, 0.21-0.74), whereas treatment effects of lanthanum, iron, and colestilan were not significant (ORs of 0.78 [95% CI, 0.16-3.72], 0.37 [95% CI, 0.09-1.60], and 0.55 [95% CI, 0.07-4.43], respectively). Lanthanum caused nausea, whereas sevelamer posed the highest risk for constipation and iron caused diarrhea. All phosphate binders lowered serum phosphorus levels to a greater extent than placebo, with iron ranked as the best treatment. Sevelamer and lanthanum posed substantially lower risks for hypercalcemia than calcium. LIMITATIONS: Limited testing of consistency; short follow-up. CONCLUSIONS: There is currently no evidence that phosphate-binder treatment reduces mortality compared to placebo in adults with CKD. It is not clear whether the higher mortality with calcium versus sevelamer reflects whether there is net harm associated with calcium, net benefit with sevelamer, both, or neither. Iron-based binders show evidence of greater phosphate lowering that warrants further examination in randomized trials.
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Quelantes/uso terapéutico , Metaanálisis en Red , Fosfatos , Insuficiencia Renal Crónica/tratamiento farmacológico , Adulto , Humanos , Lantano/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , Sevelamer/uso terapéuticoRESUMEN
One of the stranger planetary rings is Saturn's narrow, clumpy F ring, lying just outside the main rings, in a region disturbed by chaotic orbital dynamics. We show that the F ring has a stable "true core" that dominates its mass and is confined into discontinuous short arcs of particles larger than a few millimeters in radius. The more obvious micron-size particles seen in images, outlining and obscuring the true core, contribute only a small fraction of its mass. We found that these arcs of large particles orbit Saturn in a specific corotational resonance with the nearby 100-kilometer diameter ringmoon Prometheus, which stabilizes the F ring material and allows it to persist within the disturbed region for decades or longer. Toward the end of the observing period, a small chaotic glitch in the orbit of Prometheus temporarily disrupted the confinement, but the arcs seem to be able to adapt.
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BACKGROUND: End-tidal concentrations (CET) have been used to guide delivery of inhaled anesthetic drugs for many years. Effect-site concentrations (Ceff) are a frequently used guide to therapy with IV drugs and should also be of benefit with inhaled drugs, especially during periods of rapid change. For Ceff to be useful, the appropriate levels required for any given end point, and the delay between central compartment and effect, need to be defined. In this study, we explored these relationships for the effect of response to insertion of the classic laryngeal mask airway (cLMA) and compared the utility of CET and Ceff-guided cLMA insertion. METHOD: We studied 30 ASA physical status I or II patients in whom induction with sevoflurane alone and use of the cLMA were appropriate. After oxygen administration from a circle system with a total gas flow of 6 L/min, the sevoflurane vaporizer dial was set to 6%. cLMA insertion was attempted at a predetermined Ceff calculated in real time based on measured CET. Target levels were chosen using up-and-down methodology. The initial value was 2.5 vol% with a step size of 0.2 vol%. Subjects showing a gross motor response were responders, and the target was increased for the next subject. Those without such a response were nonresponders, and the target was decreased for the next subject. Data collection continued until after 7 transitions from nonresponder to responder. For each subject, after the first transition, we calculated a Ceff time series from the measured CET time series for 11 t(1/2)ke0 values between 0.5 and 5.0 minutes. We combined data from 2 studies of equilibrium 50% effective concentration (EC50) for LMA insertion to derive a pooled EC50 of 2.17%. We determined graphically the t(1/2)ke0 that gave a mean EC50 of 2.17% in our subjects. We constructed receiver operator characteristic curves to compare the utility of CET and Ceff-guided cLMA insertion. RESULTS: The 30 patients studied were all women, ASA physical status I or II, aged between 22 and 66 years (mean 38). Consciousness was lost after 99.2 (SD 11.1) seconds, and the target for cLMA insertion reached after 256 (57) seconds. The optimum t(1/2)ke0 was 2.25 minutes (95% confidence interval, 2.0-2.5 minutes). The area under the receiver operator characteristic curves was significantly different at 0.87 (SE 0.06) for Ceff and 0.63 (0.11) for CET. CONCLUSIONS: This study confirmed that real-time calculation and display of Ceff based on measured CET values are feasible. We determined the optimum t(1/2)ke0 for sevoflurane for the effect of cLMA insertion as 2.25 minutes, similar to that determined for loss of consciousness using the raw electroencephalogram. We also showed that Ceff is a more reliable (P < 0.05) guide to successful cLMA insertion than CET.
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Anestésicos por Inhalación/administración & dosificación , Máscaras Laríngeas , Éteres Metílicos/administración & dosificación , Adulto , Anciano , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Persona de Mediana Edad , Sevoflurano , Resultado del Tratamiento , Adulto JovenRESUMEN
Biomass was upgraded to fuel blendstocks via catalytic fast pyrolysis (CFP) followed by hydrotreating using three approaches: ex situ CFP with a zeolite catalyst (HZSM-5), ex situ CFP with a hydrodeoxygenation catalyst (Pt/TiO2) and cofed hydrogen, and in situ CFP with a low-cost mixed metal oxide catalyst (red mud). Each approach was evaluated using a common pine feedstock and the same hydrotreating procedure. The oxygen contents in the CFP oils ranged from 17 to 28 wt % on a dry basis, and the carbon efficiencies for the CFP processes were in the range of 28-38%. The residual oxygen was reduced to <1 wt % during hydrotreating, which was operated for 104-140 h for each CFP oil without plugging issues. The hydrotreating carbon efficiencies were 81-93%. The CFP pathway with the hydrodeoxygenation catalyst gave the highest overall carbon efficiency from biomass to fuel blendstocks (34%) but, at the same time, also the highest cumulative hydrogen consumption during CFP and hydrotreating. The zeolite pathway produced the largest fraction boiling in the gasoline range and the highest estimated octane number due to the high aromatic content in that CFP oil. The in situ red mud pathway produced the largest fraction of diesel-range products with the highest derived cetane number. However, advances in the CFP and hydrotreating process are required to improve the fuel blendstock properties for all pathways.
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The origin of Saturn's ~26.7° obliquity and ~100-million-year-old rings is unknown. The observed rapid outward migration of Saturn's largest satellite, Titan, could have raised Saturn's obliquity through a spin-orbit precession resonance with Neptune. We use Cassini data to refine estimates of Saturn's moment of inertia, finding that it is just outside the range required for the resonance. We propose that Saturn previously had an additional satellite, which we name Chrysalis, that caused Saturn's obliquity to increase through the Neptune resonance. Destabilization of Chrysalis's orbit ~100 million years ago can then explain the proximity of the system to the resonance and the formation of the rings through a grazing encounter with Saturn.
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Studies on cloned pigs are scant compared with those in mice and cattle. Expression profiles of cloned pig embryos on full-term cloned pigs are even more limited owing to the limited availability of DNA microarray technology in the pig. We have conducted expression profile comparisons between pigs from somatic cell nuclear transfer and pigs from conventional breeding at birth and 1 month of age. Differentially expressed genes that are subjected to DNA methylation were also examined for their DNA methylation status. These data will be presented in the 2009 Annual Meeting of the International Embryo Transfer Society in San Diego. In the present review, we focus on summarising existing findings on epigenetic and other changes in cloned embryo, cloned pigs and their offspring by conventional breeding.
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Clonación de Organismos , Metilación de ADN , Regulación del Desarrollo de la Expresión Génica/genética , Sus scrofa , Animales , Perfilación de la Expresión Génica , Impresión Genómica/genética , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Telómero/genéticaRESUMEN
BACKGROUND: Reducing anesthetic fresh gas flows can reduce volatile anesthetic consumption without affecting drug delivery to the patient. Delivery systems with electronic flow transducers permit the simple and accurate collection of fresh gas flow information. In a 2001 audit of fresh gas flow, we found little response to interventions designed to foster more efficient use of fresh gas. We compared current practice with our earlier results. METHODS: Flow data were collected in areas with a mix of general and acute surgery in March and November 2001, and again during 2006, by recording directly from the Datex ADU to a computer every 10 s. We extracted the distribution of flow rates when a volatile anesthetic was being administered. Data collection in March 2001 and 2006 was not advertised. RESULTS: In 2001, the mean flow rates were 1.95 and 2.1 L/min with a median flow of 1.5 L/min. In 2006, the mean was 1.27 and the median in the range 0.5-1.0 L/min. Isoflurane use decreased from 47% in 2001 to 4% in 2006. CONCLUSIONS: Fresh gas flows used in our department have decreased by 35% over 4 years. Although the absolute change in flow rate is not large, this represents potential annual savings of more than $US130,000. This occurred without specific initiatives, suggesting an evolution in practice towards lower fresh gas flow. Improvements in equipment and monitoring, including a locally developed system, which displays forward predictions of end-tidal and effect-site vapor concentrations, may be factors in this change.
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Servicio de Anestesia en Hospital/estadística & datos numéricos , Anestesia por Circuito Cerrado/tendencias , Anestésicos por Inhalación , Hospitales de Enseñanza/estadística & datos numéricos , Pautas de la Práctica en Medicina/tendencias , Servicio de Anestesia en Hospital/economía , Anestesia por Circuito Cerrado/economía , Anestesia por Circuito Cerrado/instrumentación , Anestésicos por Inhalación/economía , Ahorro de Costo , Costos de los Medicamentos , Diseño de Equipo , Hospitales de Enseñanza/economía , Humanos , Auditoría Médica , Nueva Zelanda , Procesamiento de Señales Asistido por Computador , Factores de Tiempo , TransductoresRESUMEN
Soluble epoxide hydrolase (sEH) is a phase-I xenobiotic metabolizing enzyme having both an N-terminal phosphatase activity and a C-terminal epoxide hydrolase activity. Endogenous hydrolase substrates include arachidonic acid epoxides, which have been involved in regulating blood pressure and inflammation. The subcellular localization of sEH has been controversial. Earlier studies using mouse and rat liver suggested that sEH may be cytosolic and/or peroxisomal. In this study we applied immunofluorescence and confocal microscopy using markers for different subcellular compartments to evaluate sEH colocalization in an array of human tissues. Results showed that sEH is both cytosolic and peroxisomal in human hepatocytes and renal proximal tubules and exclusively cytosolic in other sEH-containing tissues such as pancreatic islet cells, intestinal epithelium, anterior pituitary cells, adrenal gland, endometrium, lymphoid follicles, prostate ductal epithelium, alveolar wall, and blood vessels. sEH was not exclusively peroxisomal in any of the tissues evaluated. Our data suggest that human sEH subcellular localization is tissue dependent, and that sEH may have tissue- or cell-type-specific functionality. To our knowledge, this is the first report showing the subcellular localization of sEH in a wide array of human tissues.
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Epóxido Hidrolasas/metabolismo , Secuencia de Aminoácidos , Compartimento Celular , Citosol/enzimología , Técnica del Anticuerpo Fluorescente , Humanos , Microscopía Confocal , Datos de Secuencia Molecular , Especificidad de Órganos , Peroxisomas/enzimología , Solubilidad , Fracciones Subcelulares/enzimología , Análisis de Matrices TisularesRESUMEN
Soluble epoxide hydrolase (sEH) is a bifunctional enzyme with a C-terminal epoxide hydrolase activity and an N-terminal phosphatase activity. Arachidonic acid epoxides, previously suggested to be involved in apoptosis, oncogenesis and cell proliferation, are generated by cytochrome P450 epoxygenases and are good substrates of the sEH C-terminal domain. In addition, the N-terminal phosphatase domain hydrolyzes isoprenoid mono- and pyrophosphates, which are involved in cell signaling and apoptosis. Here we provide a comprehensive analysis of the distribution of sEH, CYP2C8, 2C9 and 2J2 in human neoplastic tissues using tissue micro-arrays. The human neoplastic tissue micro-arrays provide a well-controlled side by side analysis of a wide array of neoplastic tissues and their surrounding normal tissue controls. Many of the neoplastic tissues showed altered expression of these enzymes as compared to normal tissues. Altered expression was not limited to the neoplastic tissues but also found in the surrounding non-neoplastic tissues. For example, sEH expression in renal and hepatic malignant neoplasms and surrounding non-neoplastic tissues was found to be significantly decreased, whereas expression was found to be increased in seminoma as compared to normal tissues. Our study warrants further investigation of the role of altered expression of these enzymes in neoplastic tissues.
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Sistema Enzimático del Citocromo P-450/análisis , Epóxido Hidrolasas/análisis , Neoplasias/enzimología , Hidrocarburo de Aril Hidroxilasas/análisis , Citocromo P-450 CYP2C8 , Citocromo P-450 CYP2C9 , Citocromo P-450 CYP2J2 , Regulación hacia Abajo , Humanos , Inmunohistoquímica , Proteínas de Neoplasias/análisis , Oxigenasas/análisis , Solubilidad , Análisis de Matrices Tisulares , Distribución Tisular , Regulación hacia ArribaRESUMEN
Lignocellulosic biomass conversion to produce biofuels has received significant attention because of the quest for a replacement for fossil fuels. Among the various thermochemical and biochemical routes, fast pyrolysis followed by catalytic hydrotreating is considered to be a promising near-term opportunity. This paper reports on experimental methods used 1) at the National Renewable Energy Laboratory (NREL) for fast pyrolysis of lignocellulosic biomass to produce bio-oils in a fluidized-bed reactor and 2) at Pacific Northwest National Laboratory (PNNL) for catalytic hydrotreating of bio-oils in a two-stage, fixed-bed, continuous-flow catalytic reactor. The configurations of the reactor systems, the operating procedures, and the processing and analysis of feedstocks, bio-oils, and biofuels are described in detail in this paper. We also demonstrate hot-vapor filtration during fast pyrolysis to remove fine char particles and inorganic contaminants from bio-oil. Representative results showed successful conversion of biomass feedstocks to fuel-range hydrocarbon biofuels and, specifically, the effect of hot-vapor filtration on bio-oil production and upgrading. The protocols provided in this report could help to generate rigorous and reliable data for biomass pyrolysis and bio-oil hydrotreating research.
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Biocombustibles , Biomasa , Calor , Hidrocarburos/química , Catálisis , Celulosa/químicaRESUMEN
Rapid and specific detection of Mycoplasma mycoides subsp. mycoides Small Colony (M. mycoides SC) is important for the effective control of contagious bovine pleuropneumonia. Although the United States has been free of this disease for over 100 years, it is necessary to develop modern diagnostic assays that are sensitive and specific for biological agents that would affect the US agricultural industry following accidental or intentional introduction into the US agricultural population. With this aim in mind, we have identified M. mycoides SC-specific genetic loci and developed TaqMan-based PCR assays for the detection of M. mycoides SC. The TaqMan assay allows for real-time detection of specific, amplified PCR products using portable equipment, enabling testing to be performed in the field. These assays are specific for M. mycoides SC, failing to amplify DNA from other organisms belonging to the M. mycoides cluster or two phylogenetically unrelated bovine mycoplasma species. Standard curves were drawn based on the linear relationships measured between the threshold fluorescence (C(T)) values and a measured quantity of genomic DNA. M. mycoides SC was successfully detected in bronchoalveolar lavage samples obtained from experimentally infected cattle. These TaqMan-based real-time PCR assays will allow for the rapid and specific detection of M. mycoides SC.
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Enfermedades de los Bovinos/diagnóstico , ADN Bacteriano/análisis , Mycoplasma mycoides/aislamiento & purificación , Pleuroneumonía Contagiosa/diagnóstico , Reacción en Cadena de la Polimerasa/veterinaria , Animales , Secuencia de Bases , Bovinos , Enfermedades de los Bovinos/microbiología , Amplificación de Genes , Datos de Secuencia Molecular , Mycoplasma mycoides/clasificación , Mycoplasma mycoides/genética , Pleuroneumonía Contagiosa/microbiología , Reacción en Cadena de la Polimerasa/métodos , Sensibilidad y Especificidad , Especificidad de la EspecieRESUMEN
Deterioration of the thymus gland during aging is accompanied by a reduction in plasma GH. Here we report gross and microscopic results from 24-month-old Wistar-Furth rats treated with rat GH derived from syngeneic GH3 cells or with recombinant human GH. Histological evaluation of aged rats treated with either rat or human GH displayed clear morphologic evidence of thymic regeneration, reconstitution of hematopoietic cells in the bone marrow, and multiorgan extramedullary hematopoiesis. Quantitative evaluation of formalin-fixed, hematoxylin and eosin-stained sections of bone marrow from aged rats revealed at least a 50% reduction in the number hematopoietic bone marrow cells, compared with that of young 3-month-old rats. This age-associated decline in bone marrow leukocytes, as well as the increase in bone marrow adipocytes, was significantly reversed by in vivo treatment with GH. Restoration of bone marrow cellularity was caused primarily by erythrocytic and granulocytic cells, but all cell lineages were represented and their proportions were similar to those in aged control rats. On a per-cell basis, GH treatment in vivo significantly increased the number of in vitro myeloid colony forming units in both bone marrow and spleen. Morphological evidence of enhanced extramedullary hematopoiesis was observed in the spleen, liver, and adrenal glands from animals treated with GH. These results confirm that GH prevents thymic aging. Furthermore, these data significantly extend earlier findings by establishing that GH dramatically promotes reconstitution of another primary hematopoietic tissue by reversing the accumulation of bone marrow adipocytes and by restoring the number of bone marrow myeloid cells of both the erythrocytic and granulocytic lineages.
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Envejecimiento/fisiología , Células de la Médula Ósea/fisiología , Hormona del Crecimiento/fisiología , Células Madre Hematopoyéticas/fisiología , Timo/fisiología , Envejecimiento/patología , Animales , Recuento de Células , Ensayo de Unidades Formadoras de Colonias , Células Epiteliales , Femenino , Hormona del Crecimiento/farmacología , Hematopoyesis/efectos de los fármacos , Hipófisis/citología , Hipófisis/trasplante , Ratas , Ratas Endogámicas WF , Timo/patologíaRESUMEN
Soluble epoxide hydrolase (sEH) hydrolyzes a wide variety of endogenous and exogenous epoxides. Many of these epoxides are believed to be formed by cytochrome P450 epoxygenases. Here we report the distribution of sEH and cytochrome P450 epoxygenases 2C8, 2C9, and 2J2 by immunohistochemistry. A large number of different tissues from different organs were evaluated using high-throughput tissue microarrays. sEH was found in the liver, kidney, and in many other organs, including adrenals, pancreatic islets, pituitary gland, lymphoid tissues, muscles, certain vascular smooth muscles, and epithelial cells in the skin, prostatic ducts, and the gastrointestinal tract. Immunolabeling for sEH was highly specific for particular tissues and individual cell types. CYP2C9 was also found in almost all of these organs and tissues, suggesting that 2C9 and sEH are very similar in their tissue-specific patterns of expression. CYP2C8 and 2J2 were also widely distributed in human tissues but were less frequently associated with sEH. The results suggest potentially distinct pathways of endogenous fatty acid epoxide production and hydrolysis in a variety of human tissues.
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Hidrocarburo de Aril Hidroxilasas/metabolismo , Sistema Enzimático del Citocromo P-450/metabolismo , Epóxido Hidrolasas/metabolismo , Oxigenasas/metabolismo , Línea Celular , Citocromo P-450 CYP2C8 , Citocromo P-450 CYP2C9 , Citocromo P-450 CYP2J2 , Electroforesis en Gel de Poliacrilamida , Humanos , Immunoblotting , Inmunohistoquímica , Especificidad de Órganos , SolubilidadRESUMEN
The emergence of the West Nile virus (WNV) in the northeastern United States has drawn emphasis to the need for expanded arbovirus surveillance in Connecticut. Although the state of Connecticut began a comprehensive mosquito-screening program in 1997, only since 1999 have there been efforts to determine the prevalence of arboviruses in bird populations in this state. Herein, we report on our results of an arbovirus survey of 1,704 bird brains. Included in this report are the first known isolations of eastern equine encephalitis virus (EEEV) from crows and data on the geographic and temporal distribution of 1,092 WNV isolations from crow species. Moreover, these nine isolations of EEEV identify regions of Connecticut where the virus is rarely found. With the exception of WNV and EEEV, no other arboviruses were isolated or detected. Taken together, these data illustrate the distribution of avian borne EEEV and WNV in 2000 and support the need for ongoing avian arbovirus surveillance in Connecticut.
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Enfermedades de las Aves/virología , Virus de la Encefalitis Equina del Este/aislamiento & purificación , Encefalomielitis Equina Oriental/veterinaria , Pájaros Cantores/virología , Fiebre del Nilo Occidental/veterinaria , Virus del Nilo Occidental/aislamiento & purificación , Animales , Enfermedades de las Aves/epidemiología , Encéfalo/virología , Connecticut/epidemiología , Virus de la Encefalitis Equina del Este/genética , Encefalomielitis Equina Oriental/epidemiología , Encefalomielitis Equina Oriental/virología , Vigilancia de la Población , ARN Viral/análisis , ARN Viral/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Cultivo de Virus , Fiebre del Nilo Occidental/epidemiología , Fiebre del Nilo Occidental/virología , Virus del Nilo Occidental/genéticaRESUMEN
We describe the first application of a Heck arylation reaction being performed on a meta photocycloadduct. The resulting arylation/fragmentation process leads to the formation of a bridged bicyclic ketone and constitutes a dramatic increase in molecular complexity after just two synthetic operations.
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Several bis-beta-cyclodextrin porphyrins have been prepared as supramolecular receptors of carotenoids. The binding constants of carotenoids to receptors were determined by quenching the fluorescence of the porphyrins on hydrophobic binding of carotenoids within the cavities of cyclodextrins. K(a)=8.3 x 10(6) M(-1) was calculated for binding of beta,beta-carotene to bis-beta-cyclodextrin Zn porphyrin. The corresponding Ru complex catalyzes the central cleavage of carotenoids in the presence of tert-butyl hydroperoxide in a biphasic system.
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Carotenoides/química , Ciclodextrinas/química , Enzimas/química , Porfirinas/química , beta-Ciclodextrinas , Carotenoides/metabolismo , Ciclodextrinas/metabolismo , Enzimas/metabolismo , Cinética , Modelos Químicos , Imitación Molecular , Porfirinas/metabolismo , Espectrometría de FluorescenciaRESUMEN
Populations of eastern oysters Crassostrea virginica along the east coast of North America have repeatedly experienced epizootic mass mortality due to infections by protozoan parasites, and molecular diagnostic methodologies are fast becoming more widely available for the diagnosis of protozoan diseases of oysters. In this study we applied a modified version of an existing multiplex polymerase chain reaction (PCR) for detection of the eastern oyster parasites Haplosporidium nelsoni, H. costale and Perkinsus marinus from field-collected samples. We incorporated primers for DNA quality control based on the large subunit ribosomal RNA (LSU rRNA) gene of C. virginica. The multiplex PCR (MPCR) simultaneously amplified genomic DNA of C. virginica, and cloned DNA of H. nelsoni, P. marinus and H. costale. In field trial applications, we compared the performance of the MPCR to that of the conventional diagnostic techniques of histopathological tissue examination and the Ray/Mackin fluid thioglycollate medium (RMFT) assay. A total of 530 oysters were sampled from 18 sites at 12 locations along the east coast of the United States from the Gulf of Mexico to southern New England. The modified MPCR detected 21% oysters with H. nelsoni, 2% oysters with H. costale, and 40% oysters with P. marinus infections. In comparison, histopathological examination detected H. nelsoni and H. costale infections in 6 and 0.8% oysters, respectively, and the RMFT assay detected P. marinus infection in 31% oysters. The MPCR is a more sensitive diagnostic assay for detection of H. nelsoni, H. costale, and P. marinus, and incorporation of an oyster quality control product limits false negative results.