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1.
Phys Rev Lett ; 123(17): 171101, 2019 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-31702251

RESUMEN

Superradiance can trigger the formation of an ultralight boson cloud around a spinning black hole. Once formed, the boson cloud is expected to emit a nearly periodic, long-duration, gravitational-wave signal. For boson masses in the range (10^{-13}-10^{-11}) eV, and stellar mass black holes, such signals are potentially detectable by gravitational-wave detectors, like Advanced LIGO and Virgo. In this Letter, we present full band upper limits for a generic all-sky search for periodic gravitational waves in LIGO O2 data, and use them to derive-for the first time-direct constraints on the ultralight scalar boson field mass.

2.
Appetite ; 142: 104347, 2019 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-31278956

RESUMEN

Few children in the United States meet national fruit and vegetable intake recommendations, highlighting a need for interventions. Children's food preferences act as a barrier to fruit and vegetable consumption, but prior research has demonstrated that repeated taste exposures can increase children's acceptance of these foods. Prior research in this area has typically utilized controlled procedures in which children sample small tastes of target foods over repeated occasions. The primary aim of the present pilot study was to test whether children's preferences for target fruits and vegetables increased following repeated taste exposures to them through hands-on cooking in a community setting. Seventeen 6-to-8-year-old children participated in biweekly study sessions during six weeks of a summer camp serving lower-income families. Liking of (yummy, just OK, yucky) and rank-ordered preferences for nine fruits and vegetables were measured before and after exposure sessions (pre-test and post-test). Based on pre-test assessments, four relatively less liked foods (two fruits, two vegetables) were chosen to become target foods. Children were then exposed to target foods during nine hands-on cooking sessions; liking of target foods was also measured at a midpoint assessment. At each exposure session, children assisted with preparation of a different snack using a recipe involving target foods and then ate the prepared snack together. Preferences for target foods increased from pre-test (Median = 5.8) to post-test (Median = 5.5; p < 0.05). On average, the majority of children rated the prepared snacks favorably. Results from this pilot study demonstrate the potential of applying repeated exposure techniques via hands-on cooking in a community setting.


Asunto(s)
Culinaria/métodos , Preferencias Alimentarias/psicología , Frutas , Educación en Salud/métodos , Promoción de la Salud/métodos , Verduras , Niño , Femenino , Asistencia Alimentaria , Humanos , Masculino , New York , Proyectos Piloto , Pobreza , Ingesta Diaria Recomendada , Bocadillos
3.
J Fish Dis ; 39(3): 353-66, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25939872

RESUMEN

Lake trout Salvelinus namaycush (Walbaum) raised for stocking experienced yearly (2011-13) winter epizootics of epitheliocystis. Affected fish were dispersed on the bottom of the tank, had decreased feed and fright response, and mortality often reached 40%. Peak mortality occurred within 3 weeks of the appearance of clinical signs, and outbreaks typically lasted 6 weeks. Affected fish had no gross lesions but histologically had branchial epithelial necrosis and lamellar hyperplasia, with small to large numbers of scattered epithelial cells containing 10- to 20-µm inclusions. A longitudinal study was undertaken of one annual outbreak, and lamellar hyperplasia was most closely associated with mortality. The number of inclusions was statistically greater (P < 0.05) before and during peak mortality, but inclusions were present in low numbers before clinical signs occurred. Results of histochemical staining, immunohistochemistry and transmission electron microscopy supported the presence of a ß-proteobacteria rather than a Chlamydiales bacterium within inclusions. PCR primers to identify Chlamydiales did not give consistent results. However, the use of universal 16S rDNA bacterial primers in conjunction with laser capture microdissection of inclusions demonstrated that a ß-proteobacteria was consistently associated with affected gills and is more likely the cause of the disease in lake trout.


Asunto(s)
Epitelio/microbiología , Enfermedades de los Peces/microbiología , Branquias/microbiología , Necrosis/veterinaria , Proteobacteria/fisiología , Trucha/microbiología , Animales , Enfermedades de los Peces/mortalidad , Enfermedades de los Peces/patología , Branquias/patología , Branquias/ultraestructura , Hiperplasia/microbiología , Hiperplasia/mortalidad , Hiperplasia/patología , Hiperplasia/veterinaria , Inmunohistoquímica , Estudios Longitudinales , Microscopía Electrónica de Transmisión , Necrosis/microbiología , Necrosis/mortalidad , Necrosis/patología , Proteobacteria/genética , ARN Ribosómico 16S/genética
4.
Vet Pathol ; 50(3): 368-76, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23528940

RESUMEN

A retrospective study of the pathologic findings in weedy (Phyllopteryx taeniolatus) and leafy (Phycodurus eques) seadragons was performed on specimens submitted to 2 reference laboratories from 1994 to 2012 to determine the range and occurrence of diseases affecting aquarium-held populations. One hundred two and 94 total diagnoses were recorded in weedy and leafy seadragons, respectively. Two of the more common etiologic diagnoses in both species were mycobacteriosis and scuticociliatosis, whereas myxozoanosis was common in weedy seadragons. Metazoan parasite infections were less common etiologic diagnoses. There were no correlations between mycobacteriosis and ciliate protozoan infections in either species. Myxozoanosis was usually found in combination with other diseases and, except for 1 case, was restricted to weedy seadragons. Phaeohyphomycosis, nonmycobacterial bacterial infections, and trauma were also important but less frequent diagnoses. Intestinal coccidiosis was found in weedy but not leafy seadragons. Mineralization of the swim bladder was detected in 26 of 197 leafy seadragons and only 2 of 257 weedy seadragons. Although weedy and leafy seadragons share certain diseases of significance to exhibit populations, there are diseases unique to each species about which the veterinary pathologist, clinician, or diagnostician should be aware.


Asunto(s)
Infecciones Bacterianas/veterinaria , Enfermedades de los Peces/patología , Enfermedades Parasitarias en Animales/patología , Feohifomicosis/veterinaria , Smegmamorpha , Sacos Aéreos/patología , Animales , Infecciones Bacterianas/patología , Infecciones por Cilióforos/patología , Infecciones por Cilióforos/veterinaria , Coccidiosis/patología , Coccidiosis/veterinaria , Enfermedades de los Peces/microbiología , Enfermedades de los Peces/parasitología , Branquias/patología , Infecciones por Mycobacterium no Tuberculosas/patología , Infecciones por Mycobacterium no Tuberculosas/veterinaria , Oligohimenóforos/aislamiento & purificación , Feohifomicosis/patología , Estudios Retrospectivos , Piel/patología , Smegmamorpha/microbiología , Smegmamorpha/parasitología , Especificidad de la Especie
5.
Infect Immun ; 78(8): 3475-83, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20515935

RESUMEN

Many lipoproteins are expressed on the surfaces of mycoplasmas, and some have been implicated as playing roles in pathogenesis. Family 2 lipoproteins of Mycoplasma pneumoniae have a conserved "mycoplasma lipoprotein X" central domain and a "mycoplasma lipoprotein 10" C-terminal domain and are differentially expressed in response to environmental conditions. Homologues of family 2 lipoproteins are Mycoplasma specific and include the lipoprotein of Mycoplasma gallisepticum, encoded by the MGA0674 gene. Comparative transcriptomic analysis of the M. gallisepticum live attenuated vaccine strain F and the virulent strain R(low), reported in this study, indicated that MGA0674 is one of several differentially expressed genes. The MGA0674-encoded lipoprotein is a proteolytically processed, immunogenic, TX-114 detergent-phase protein which appears to have antigenic divergence between field strains R(low) and S6. We examined the virulence of an R(low) Delta MGA0674 mutant (P1H9) in vivo and observed reduced recovery and attenuated virulence in the tracheas of experimentally infected chickens. The virulence of two additional R(low) Delta MGA0674 mutants, 2162 and 2204, was assessed in a second in vivo virulence experiment. These mutants exhibited partial to complete attenuation in vivo, but recovery was observed more frequently. Since only Mycoplasma species harbor homologues of MGA0674, the gene product has been renamed "Mycoplasma-specific lipoprotein A" (MslA). Collectively, these data indicate that MslA is an immunogenic lipoprotein exhibiting reduced expression in an attenuated strain and plays a role in M. gallisepticum virulence.


Asunto(s)
Proteínas Bacterianas/fisiología , Lipoproteínas/fisiología , Infecciones por Mycoplasma/veterinaria , Mycoplasma gallisepticum/patogenicidad , Enfermedades de las Aves de Corral/microbiología , Factores de Virulencia/fisiología , Animales , Proteínas Bacterianas/genética , Pollos , Femenino , Eliminación de Gen , Perfilación de la Expresión Génica , Lipoproteínas/deficiencia , Infecciones por Mycoplasma/microbiología , Infecciones por Mycoplasma/patología , Enfermedades de las Aves de Corral/patología , Tráquea/microbiología , Tráquea/patología , Virulencia , Factores de Virulencia/deficiencia
6.
Infect Immun ; 78(4): 1760-71, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20123709

RESUMEN

Mycoplasma gallisepticum is a significant respiratory and reproductive pathogen of domestic poultry. While the complete genomic sequence of the virulent, low-passage M. gallisepticum strain R (R(low)) has been reported, genomic determinants responsible for differences in virulence and host range remain to be completely identified. Here, we utilize genome sequencing and microarray-based comparative genomic data to identify these genomic determinants of virulence and to elucidate genomic variability among strains of M. gallisepticum. Analysis of the high-passage, attenuated derivative of R(low), R(high), indicated that relatively few total genomic changes (64 loci) occurred, yet they are potentially responsible for the observed attenuation of this strain. In addition to previously characterized mutations in cytadherence-related proteins, changes included those in coding sequences of genes involved in sugar metabolism. Analyses of the genome of the M. gallisepticum vaccine strain F revealed numerous differences relative to strain R, including a highly divergent complement of vlhA surface lipoprotein genes, and at least 16 genes absent or significantly fragmented relative to strain R. Notably, an R(low) isogenic mutant in one of these genes (MGA_1107) caused significantly fewer severe tracheal lesions in the natural host compared to virulent M. gallisepticum R(low). Comparative genomic hybridizations indicated few genetic loci commonly affected in F and vaccine strains ts-11 and 6/85, which would correlate with proteins affecting strain R virulence. Together, these data provide novel insights into inter- and intrastrain M. gallisepticum genomic variability and the genetic basis of M. gallisepticum virulence.


Asunto(s)
ADN Bacteriano/genética , Genoma Bacteriano , Infecciones por Mycoplasma/veterinaria , Mycoplasma gallisepticum/genética , Mycoplasma gallisepticum/patogenicidad , Enfermedades de las Aves de Corral/microbiología , Factores de Virulencia/genética , Animales , Pollos , Hibridación Genómica Comparativa , ADN Bacteriano/química , Femenino , Datos de Secuencia Molecular , Análisis de Secuencia de ADN
7.
Obes Rev ; 19(4): 576-604, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29266778

RESUMEN

The palatable, energy-dense foods that characterize modern environments can promote unhealthy eating habits, along with humans' predispositions to accept sweet tastes and reject those that are sour or bitter. Yet food preferences are malleable, and examining food preference learning during early life can highlight ways to promote acceptance of healthier foods. This narrative review describes research from the past 10 years focused on food preference learning from the prenatal period through early childhood (ages 2-5 years). Exposure to a variety of healthy foods from the start, including during the prenatal period, early milk-feeding and the introduction to complementary foods and beverages, can support subsequent acceptance of those foods. Yet development is plastic, and healthier food preferences can still be promoted after infancy. In early childhood, research supports starting with the simplest strategies, such as repeated exposure and modelling, reserving other strategies for use when needed to motivate the initial tasting necessary for repeated exposure effects to begin. This review can help caregivers and practitioners to promote the development of healthy food preferences early in life. Specific implementation recommendations, the role of individual differences and next steps for research in this area are also discussed.


Asunto(s)
Conducta Alimentaria/psicología , Preferencias Alimentarias/psicología , Promoción de la Salud , Responsabilidad Parental , Desarrollo Infantil , Fenómenos Fisiológicos Nutricionales Infantiles , Preescolar , Ingestión de Alimentos , Conducta Alimentaria/fisiología , Femenino , Humanos , Lactante , Recién Nacido , Relaciones Padres-Hijo , Embarazo
9.
Artículo en Inglés | MEDLINE | ID: mdl-25573031

RESUMEN

In this study, we develop a two-dimensional finite element model, which is derived from an animal experiment and allows simulating osteogenesis within a porous titanium scaffold implanted in ewe's hemi-mandible during 12 weeks. The cell activity is described through diffusion equations and regulated by the stress state of the structure. We compare our model to (i) histological observations and (ii) experimental data obtained from a mechanical test done on sacrificed animal. We show that our mechano-biological approach provides consistent numerical results and constitutes a useful tool to predict osteogenesis pattern.


Asunto(s)
Modelos Biológicos , Osteogénesis/efectos de los fármacos , Andamios del Tejido/química , Titanio/farmacología , Animales , Difusión , Femenino , Análisis de Elementos Finitos , Mandíbula/efectos de los fármacos , Células Madre Mesenquimatosas/citología , Células Madre Mesenquimatosas/efectos de los fármacos , Porosidad , Prótesis e Implantes , Ovinos
10.
Pediatr Obes ; 11(5): 333-48, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-26842913

RESUMEN

BACKGROUND: Breakfast consumption has been associated with reduced risk of overweight and obesity among children, but previous evidence reviews fail to confirm a causal relationship. OBJECTIVES: To review recent literature on breakfast consumption and adiposity among children and discuss potential underlying mechanisms. METHODS: A comprehensive literature search of studies published since the 2010 US National Evidence Library review (January 2010-January 2015) was conducted. RESULTS: Twelve studies met inclusion criteria. All were conducted in industrialized countries: six in Europe, four in the USA, one in China and one in Australia. Ten of the studies used observational longitudinal designs, with follow-up periods ranging from 1 to 27 years (median: 3, mean: 7.4); of these, eight reported inverse associations between breakfast consumption and excess adiposity, while two found no association. The other studies (1 case-control, 1 experimental) each reported a protective effect of breakfast consumption on overweight and obesity among children. CONCLUSIONS: Findings corroborate results from previous reviews, adding support for a possible, protective role for breakfast consumption in preventing excess adiposity during childhood and adolescence. However, drawing a causal conclusion from the collective evidence is curtailed by methodological limitations and inconsistencies, including study design, follow-up duration and frequency, exposure and outcome assessment, as well as limited consideration of confounding, mediating and effect-modifying variables. More rigorous study designs employing valid and standardized measurement of relevant variables are needed.


Asunto(s)
Adiposidad/fisiología , Desayuno/fisiología , Sobrepeso/prevención & control , Obesidad Infantil/prevención & control , Adolescente , Australia , Índice de Masa Corporal , Niño , China , Europa (Continente) , Humanos , Masculino , Evaluación de Resultado en la Atención de Salud , Estados Unidos
11.
Phys Rev Lett ; 84(1): 14-7, 2000 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-11015823

RESUMEN

The passage of cosmic rays has been observed to excite mechanical vibrations in the resonant gravitational wave detector NAUTILUS operating at temperature of 100 mK. A very significant correlation (more than 10 standard deviations) is found.

12.
Phys Rev Lett ; 85(24): 5046-50, 2000 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-11102183

RESUMEN

We report the initial results from a search for bursts of gravitational radiation by a network of five cryogenic resonant detectors during 1997 and 1998. This is the first significant search with more than two detectors observing simultaneously. No gravitational wave burst was detected. The false alarm rate was lower than 1 per 10(4) yr when three or more detectors were operating simultaneously. The typical threshold was H approximately 4x10(-21) Hz-1 on the Fourier component at approximately 10(3) Hz of the gravitational wave strain amplitude. New upper limits for amplitude and rate of gravitational wave bursts have been set.

13.
J Vet Diagn Invest ; 13(6): 524-30, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11724146

RESUMEN

A 16-year-old female white whale, Delphinapterus leucas, died after nearly 18 months of chronic lymphopenia and pyogranulomatous dermatitis. Necropsy revealed rupture of the aorta with hemorrhage into the cranial mediastinum and between fascial planes of the ventral neck musculature. Multiple foci of ulcerative dermatitis and panniculitis were present across the thorax and abdomen and surrounded the genital folds. In addition, there was a chronic proliferative pleuritis with over 20 liters of histiocytic exudate in the thoracic cavity. Acid-fast bacteria consistent with Mycobacterium sp. were identified in sections of skin lesions and in cytospins of pleural exudate. Cultures of pleura and 1 skin lesion collected at necropsy yielded sparse growth of an acid-fast bacillus with colony characteristics and morphology consistent with Mycobacterium marinum. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis confirmed the presence of M. marinum DNA in samples of skin. This is the first documented occurrence of mycobacteriosis in a white whale and is a unique presentation of mycobacterial dermatitis and panniculitis with chronic pleuritis in a cetacean. The improved PCR-RFLP protocol utilized in this case unifies techniques from several protocols to differentiate between species of Nocardia and rapidly growing mycobacteria clinically relevant to aquatic animals.


Asunto(s)
Rotura de la Aorta/veterinaria , Dermatitis/veterinaria , Infecciones por Mycobacterium no Tuberculosas/veterinaria , Mycobacterium marinum/aislamiento & purificación , Paniculitis/veterinaria , Enfermedades Pleurales/veterinaria , Ballenas/microbiología , Animales , Enfermedad Crónica , ADN Bacteriano/análisis , Dermatitis/microbiología , Resultado Fatal , Femenino , Infecciones por Mycobacterium no Tuberculosas/complicaciones , Mycobacterium marinum/patogenicidad , Paniculitis/microbiología , Enfermedades Pleurales/microbiología , Reacción en Cadena de la Polimerasa/veterinaria , Polimorfismo de Longitud del Fragmento de Restricción
14.
Avian Dis ; 41(2): 475-80, 1997.
Artículo en Inglés | MEDLINE | ID: mdl-9201419

RESUMEN

Multiple intussusceptions of the small intestine were identified in a 4-mo-old rhea (Rhea americana) that died acutely after chronically poor growth. The chick was one of a group of 12 chicks that exhibited musculoskeletal deformities, poor growth, and subsequent death. Gross necropsy findings of this chick revealed proventricular impaction by sticks and stones accompanied by multiple intussusceptions of the small intestine. This finding identifies a disease process that may afflict ratites when raised for production and that may complicate treatment of proventricular impaction.


Asunto(s)
Enfermedades de las Aves , Aves/anomalías , Intestino Delgado/patología , Intususcepción/veterinaria , Proventrículo/patología , Gastropatías/veterinaria , Anomalías Múltiples/patología , Anomalías Múltiples/veterinaria , Animales , Enfermedades del Colon/patología , Enfermedades del Colon/veterinaria , Enfermedades Duodenales/patología , Enfermedades Duodenales/veterinaria , Femenino , Enfermedades del Íleon/patología , Enfermedades del Íleon/veterinaria , Intususcepción/patología , Enfermedades del Yeyuno/patología , Enfermedades del Yeyuno/veterinaria , Gastropatías/patología
15.
Avian Dis ; 43(3): 616-21, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10494437

RESUMEN

Proliferative cutaneous lesions are frequently encountered in examination of avian species. Tumors of the skin have been reported in many bird species, although comparatively less is known about the incidence of integumentary neoplasia in nondomesticated species than in production or companion species. An adult male, 9-yr-old, captive-bred barn owl (Tyto alba) was presented for examination of a proliferative skin mass of several months' duration on the left wing. An excisional biopsy was performed, and the owl recovered uneventfully. Light microscopic examination of tissue sections of the mass revealed a focal, unencapsulated, well-demarcated, multiloculated mass that consisted of variably sized cystic spaces lined by stratified squamous epithelium and containing concentric laminations of keratin and foci of feather differentiation. A histopathologic diagnosis of feather folliculoma was made. This neoplasm has not previously been described in owls. Its incidence and documentation are significant in that this neoplasm should be considered as a differential diagnosis of proliferative skin lesions in this raptorial species.


Asunto(s)
Enfermedades de las Aves/patología , Plumas , Neoplasias Cutáneas/veterinaria , Estrigiformes , Animales , Biopsia , Masculino , Neoplasias Cutáneas/patología , Alas de Animales
16.
Dis Aquat Organ ; 32(3): 211-25, 1998 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-9676246

RESUMEN

In 1995 at a sea-farm in Ireland, Atlantic salmon Salmo salar smolts were introduced in the spring and autumn into 2 marine rearing sites, one with and one without recent histories of neurologic disease and mass mortality believed to be due to parasitic encephalitis. In order to monitor disease, determine the onset and anatomic distribution of parasites and encephalitis, and determine the ultrastructure and identity of the parasite, randomly selected smolts were necropsied from both sites at intervals of 1 to 3 d for periods of 1 to 2 mo, and clinical signs and cumulative mortalities were monitored. The prevalences of parasites and encephalitis were assessed by light microscopy, and sections of brain were examined by transmission electron microscopy. No clinical signs of neurologic disease were observed, but parasites and encephalitis were detected in smolts from both sites, with prevalences of each that were significantly greater in smolts from the site with recent disease. Based on light microscopy, the parasite was first detected in smolts sampled at 26 d post-introduction. Parasites were detected with significantly greater frequency in the optic tectum of the mesencephalon than in the diencephalon, metencephalon, and myelencephalon, and were not detected in the telencephalon. Foci of non-suppurative encephalitis were detected with significantly greater frequency in the myelencephalon than in each of the other 4 anatomic subdivisions. In each anatomic subdivision the prevalence of encephalitis was significantly greater than that of parasitic infection. The ultrastructure of the parasite was consistent with that of a histozoic presporogonic multicellular developmental stage of a myxosporean, characterized by intercellular branching tubular structures containing generative cells arranged individually or in cell-in-cell doublets. Parasitic stages were located between bundles of axons, with compression of axons along segments of their plasmalemma. No mature spores were detected.


Asunto(s)
Encefalitis/veterinaria , Eucariontes/ultraestructura , Enfermedades de los Peces/epidemiología , Infecciones Protozoarias en Animales/epidemiología , Salmón/parasitología , Animales , Encéfalo/parasitología , Encéfalo/patología , Encéfalo/ultraestructura , Brotes de Enfermedades/veterinaria , Encefalitis/epidemiología , Encefalitis/parasitología , Eucariontes/clasificación , Eucariontes/crecimiento & desarrollo , Enfermedades de los Peces/parasitología , Enfermedades de los Peces/patología , Explotaciones Pesqueras , Irlanda/epidemiología , Microscopía Electrónica/veterinaria , Prevalencia , Infecciones Protozoarias en Animales/parasitología , Infecciones Protozoarias en Animales/patología , Estaciones del Año
17.
Dis Aquat Organ ; 35(3): 221-33, 1999 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-10228877

RESUMEN

During seasonal epizootics of neurologic disease and mass mortality in the summers of 1992, 1993 and 1994 on a sea-farm in Ireland, Atlantic salmon Salmo salar smolts suffered from encephalitis associated with infection by a neurotropic parasite. Based on ultrastructural studies, this neurotropic parasite was identified as an intercellular presporogonic multicellular developmental stage of a histozoic myxosporean, possibly a Myxobolus species. In order to generate sequence data for phylogenetic comparisons to substantiate the present morphological identification of this myxosporean in the absence of detectable sporogony, polymerase chain reaction (PCR), Southern blot hybridization, dideoxynucleotide chain-termination DNA sequencing, and in situ hybridization (ISH) were used in concert to characterize segments of the small subunit ribosomal RNA (SSU rRNA) gene. Oligonucleotide primers were created from sequences of the SSU rRNA gene of M. cerebralis and were employed in PCR experiments using DNA extracted from formalin-fixed paraffin-embedded tissue sections of brains from Atlantic salmon smolts in which the myxosporean had been detected by light microscopy. Five segments of the SSU rRNA gene of the myxosporean, ranging in length from 187 to 287 base pairs, were amplified, detected by hybridization with sequence-specific probes, and sequenced. Consensus sequences from these segments were aligned to create a partial sequence of the SSU rRNA gene of the myxosporean. Assessments of sequence identity were made between this partial sequence and sequences of SSU rRNA genes from 7 myxosporeans, including Ceratomyxa shasta, Henneguya doori, M. arcticus, M. cerebralis, M. insidiosus, M. neurobius, and M. squamalis. The partial SSU rRNA gene sequence from the myxosporean had more sequence identity with SSU rRNA gene sequences from neurotropic and myotropic species of Myxobolus than to those from epitheliotropic species of Myxobolus or Henneguya, or the enterotropic species of Ceratomyxa, and was identical to regions of the SSU rRNA gene of M. cerebralis. Digoxigenin-labeled oligonucleotide DNA probes complementary to multiple segments of the SSU rRNA gene of M. cerebralis hybridized with DNA of the parasite in histologic sections of brain in ISH experiments, demonstrating definitively that the segments of genome amplified were from the organisms identified by histology and ultrastructural analysis. Based on sequence data derived entirely from genetic material of extrasporogonic stages, the SSU rDNA sequence identity discovered in this study supports the hypothesis that the myxosporean associated with encephalitis of farmed Atlantic salmon smolts is a neurotropic species of the genus Myxobolus, with sequences identical to those of M. cerebralis.


Asunto(s)
Encefalitis/veterinaria , Eucariontes/genética , Enfermedades de los Peces/parasitología , Infecciones Protozoarias en Animales/patología , Salmo salar/parasitología , Animales , Secuencia de Bases , Encéfalo/parasitología , Encéfalo/patología , Encefalitis/genética , Encefalitis/parasitología , Enfermedades de los Peces/genética , Enfermedades de los Peces/patología , Explotaciones Pesqueras , Hibridación in Situ/veterinaria , Irlanda , Microscopía Electrónica/veterinaria , Datos de Secuencia Molecular , Prevalencia , Infecciones Protozoarias en Animales/genética , Infecciones Protozoarias en Animales/parasitología , Estaciones del Año
18.
Rev Sci Instrum ; 50(12): 1650, 1979 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18699455

RESUMEN

A technique for measuring the resonance frequencies of an aluminum bar (used as a gravitational antenna) with high accuracy is presented. This method is based on the positive feedback of the bar, and is much faster than the others commonly in use.

19.
J Parasitol ; 86(3): 618-22, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10864264

RESUMEN

Skin lesions caused by the ectoparasite Dermophthirius penneri Benz, 1987 (Monogenea: Microbothriidae) on 2 wild-caught blacktip sharks (Carcharhinus limbatus) from the northern Gulf of Mexico were studied using light and scanning electron microscopy. Grossly, lesions appeared as multifocal, well-demarcated, ovoid or irregularly shaped, light gray patches of skin. Scanning electron microscopy of lesions revealed gaps between placoid scales apparently created by detachment and loss of placoid scales, rotated and tilted placoid scales with blunt distal tips and shallow ridges, and a frayed epithelium that covered some placoid scales and filled some spaces between placoid scales. Light microscopy of lesions revealed epithelial hyperplasia accompanied by dermal infiltrates of moderate numbers of loosely arranged lymphocytes interposed between collagen bundles in the superficial layers of the stratum compactum. This report provides the first details of microbothriid skin lesions on wild sharks. Our results indicate that D. penneri caused chronic skin lesions not associated with bacterial infection or severe, debilitating, skin disease in the studied sharks.


Asunto(s)
Enfermedades de los Peces/parasitología , Platelmintos/patogenicidad , Tiburones/parasitología , Enfermedades Cutáneas Parasitarias/veterinaria , Piel/parasitología , Infecciones por Trematodos/veterinaria , Animales , Femenino , Enfermedades de los Peces/patología , Microscopía Electrónica de Rastreo , Mississippi , Piel/patología , Piel/ultraestructura , Enfermedades Cutáneas Parasitarias/parasitología , Enfermedades Cutáneas Parasitarias/patología , Infecciones por Trematodos/parasitología , Infecciones por Trematodos/patología
20.
J Parasitol ; 87(6): 1429-32, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11780833

RESUMEN

A new dracunculoid nematode Syngnathinema californiense, n. gen., n. sp., is described from gravid female parasites found inside the heart of wild-caught Bay pipefish Syngnathus leptorhynchus; histologically it was recorded from different sites of the host circulatory system (sinus venosus, atrium, and renal and hepatic veins). The new genus is characterized by the structure of the cephalic end (large oral aperture with a narrow peribuccal ring surrounded by 10 papillae in 2 circles, large circular amphids), division of the esophagus into muscular and glandular portions, location of the well-developed vulva posterior to the esophagus, monodelphic female reproductive organs, and the sharply pointed tail. Because males remain unknown, the genus is provisionally assigned to the Daniconematidae.


Asunto(s)
Sistema Cardiovascular/parasitología , Dracunculoidea/clasificación , Enfermedades de los Peces/parasitología , Infecciones por Spirurida/veterinaria , Animales , California , Dracunculoidea/anatomía & histología , Femenino , Peces
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