Extradural undifferentiated sarcoma causing spinal cord compression in 2 horses     

Van Biervliet J  Alcaraz A  Jackson CA  Njaa B  de Lahunta A  Divers TJ 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2004,18(2):248-251

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Molecular diversity of Moraxella bovis isolated from Brazil, Argentina and Uruguay over a period of three decades     

Conceição FR  Dellagostin OA  Paolichi F  Leturia AC  Gil Turnes C 《Veterinary journal (London, England : 1997)》2004,167(1):53-58

The molecular profile of 30 Moraxella bovis strains, recovered from outbreaks of infectious bovine keratoconjunctivitis in Argentina, Brazil and Uruguay between 1974 and 2001, was determined through randomly applied polymorphic DNA (RAPD) analysis. Molecular profiles of nine strains recovered after 1990 varied from those recovered before 1990. The profiles of 13 strains (48%) differed from those of three vaccinal strains extensively used since 1984 in Argentina and Uruguay. Eight Argentinean strains, one from Brazil and two from Uruguay had identical RAPD profiles. Strains belonging to different serogroups had identical RAPD profiles, demonstrating that this technique was not able to discriminate among strains with low cross-reactivity indices. RAPD may be helpful in the primary characterization of M. bovis strains, but it does not replace serological characterization.  相似文献   

Influence of glycosidic linkages and molecular weight on the fermentation of maltose-based oligosaccharides by human gut bacteria     

Sanz ML  Côté GL  Gibson GR  Rastall RA 《Journal of agricultural and food chemistry》2006,54(26):9779-9784

A structure-function study was carried out to increase knowledge of how glycosidic linkages and molecular weights of carbohydrates contribute toward the selectivity of fermentation by gut bacteria. Oligosaccharides with maltose as the common carbohydrate source were used. Potentially prebiotic alternansucrase and dextransucrase maltose acceptor products were synthesized and separated into different molecular weights using a Bio-gel P2 column. These fractions were characterized by matrix-assisted laser desorption/ionization time-of-flight. Nonprebiotic maltooligosaccharides with degrees of polymerization (DP) from three to seven were commercially obtained for comparison. Growth selectivity of fecal bacteria on these oligosaccharides was studied using an anaerobic in vitro fermentation method. In general, carbohydrates of DP3 showed the highest selectivity towards bifidobacteria; however, oligosaccharides with a higher molecular weight (DP6-DP7) also resulted in a selective fermentation. Oligosaccharides with DPs above seven did not promote the growth of "beneficial" bacteria. The knowledge of how specific structures modify the gut microflora could help to find new prebiotic oligosaccharides.  相似文献   

Non-invasive assessment of growth, gender and time of day related changes of respiratory pattern in healthy cats by use of barometric whole body plethysmography     

Kirschvink N  Leemans J  Delvaux F  Snaps F  Marlin D  Sparkes A  Clercx C  Gustin P 《Veterinary journal (London, England : 1997)》2006,172(3):446-454

The objective of this study was to establish a reference base for respiratory variables (respiratory rate [R(R)], inspiratory and expiratory time [T(i) and T(e)], peak inspiratory and expiratory pseudoflow [PIF and PEF], tidal volume [V(T)], minute ventilation [V(E)] and enhanced pause [Penh]) of healthy cats by use of barometric whole body plethysmography (BWBP). Eighteen healthy European cats (10 male, 8 female) were studied from the age of 3 to 13 months in order to assess growth- and gender-related changes of BWBP variables. Chest radiographs and bronchoalveolar lavage cytology were performed to confirm pulmonary health status. Diurnal changes were investigated every 2 h over a period of 24 h when the cats were adult. V(T), V(E), PIF and PEF significantly increased during somatic growth and were higher in males than in females, whereas R(R), T(i), T(e), T(e)/T(i) ratio, PEF/PIF ratio and Penh remained unchanged and were not affected by gender. When measured over 24 h, Penh, T(e) and T(i) were significantly increased in the early morning hours (04:00 h), whereas R(R), PIF and PEF were decreased at that time. This study provides reference values of BWBP variables for healthy male and female cats and indicates when circadian changes might be observed.  相似文献   

Organics captured from comet 81P/Wild 2 by the Stardust spacecraft     

Sandford SA  Aléon J  Alexander CM  Araki T  Bajt S  Baratta GA  Borg J  Bradley JP  Brownlee DE  Brucato JR  Burchell MJ  Busemann H  Butterworth A  Clemett SJ  Cody G  Colangeli L  Cooper G  D'Hendecourt L  Djouadi Z  Dworkin JP  Ferrini G  Fleckenstein H  Flynn GJ  Franchi IA  Fries M  Gilles MK  Glavin DP  Gounelle M  Grossemy F  Jacobsen C  Keller LP  Kilcoyne AL  Leitner J  Matrajt G  Meibom A  Mennella V  Mostefaoui S  Nittler LR  Palumbo ME  Papanastassiou DA  Robert F  Rotundi A  Snead CJ  Spencer MK  Stadermann FJ  Steele A 《Science (New York, N.Y.)》2006,314(5806):1720-1724

Organics found in comet 81P/Wild 2 samples show a heterogeneous and unequilibrated distribution in abundance and composition. Some organics are similar, but not identical, to those in interplanetary dust particles and carbonaceous meteorites. A class of aromatic-poor organic material is also present. The organics are rich in oxygen and nitrogen compared with meteoritic organics. Aromatic compounds are present, but the samples tend to be relatively poorer in aromatics than are meteorites and interplanetary dust particles. The presence of deuterium and nitrogen-15 excesses suggest that some organics have an interstellar/protostellar heritage. Although the variable extent of modification of these materials by impact capture is not yet fully constrained, a diverse suite of organic compounds is present and identifiable within the returned samples.  相似文献   

Efficacy of using an internal teat sealer to prevent new intramammary infections in nonlactating dairy cattle     

Sanford CJ  Keefe GP  Dohoo IR  Leslie KE  Dingwell RT  DesCôteaux L  Barkema HW 《Journal of the American Veterinary Medical Association》2006,228(10):1565-1573

OBJECTIVE: To determine whether insertion of an internal teat sealer (ITS) at the end of lactation would prevent development of new intramammary infections (IMIs) during the nonlactating period. DESIGN: Controlled clinical trial. ANIMALS: 939 Holstein-Friesian dairy cows from 16 herds. PROCEDURES: Results of bacteriologic culture of milk samples collected 14 days prior to the end of lactation were used to assign cows to groups (group 1 = negative results for all quarters; group 2 = positive results for > or = 1 quarter). Quarters of cows in group 1 were treated with an ITS or a single intramammary dose of cloxacillin; quarters of cows in group 2 were treated with cloxacillin in conjunction with an ITS or with cloxacillin alone. Milk samples were collected at the end of lactation and within 8 days after calving. RESULTS: Regardless of whether the outcome of interest was new IMIs caused by any pathogens, major pathogens, environmental pathogens, or streptococci other than Streptococcus agalactiae, quarters in group 2 treated with both cloxacillin and an ITS were less likely to develop a new IMI than were quarters treated with cloxacillin alone. For cows in group 1, no significant difference in risk of new IMIs was found between treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that for dairy cattle with an IMI late in the lactation period, intramammary administration of cloxacillin at the end of lactation followed by insertion of an ITS enhanced protection against development of new IMIs, compared with use of cloxacillin alone.  相似文献   

Carbon isotope constraints on the deglacial CO₂ rise from ice cores     

Schmitt J  Schneider R  Elsig J  Leuenberger D  Lourantou A  Chappellaz J  Köhler P  Joos F  Stocker TF  Leuenberger M  Fischer H 《Science (New York, N.Y.)》2012,336(6082):711-714

The stable carbon isotope ratio of atmospheric CO(2) (δ(13)C(atm)) is a key parameter in deciphering past carbon cycle changes. Here we present δ(13)C(atm) data for the past 24,000 years derived from three independent records from two Antarctic ice cores. We conclude that a pronounced 0.3 per mil decrease in δ(13)C(atm) during the early deglaciation can be best explained by upwelling of old, carbon-enriched waters in the Southern Ocean. Later in the deglaciation, regrowth of the terrestrial biosphere, changes in sea surface temperature, and ocean circulation governed the δ(13)C(atm) evolution. During the Last Glacial Maximum, δ(13)C(atm) and atmospheric CO(2) concentration were essentially constant, which suggests that the carbon cycle was in dynamic equilibrium and that the net transfer of carbon to the deep ocean had occurred before then.  相似文献   

A long-lived lunar core dynamo     

Shea EK  Weiss BP  Cassata WS  Shuster DL  Tikoo SM  Gattacceca J  Grove TL  Fuller MD 《Science (New York, N.Y.)》2012,335(6067):453-456

Paleomagnetic measurements indicate that a core dynamo probably existed on the Moon 4.2 billion years ago. However, the subsequent history of the lunar core dynamo is unknown. Here we report paleomagnetic, petrologic, and (40)Ar/(39)Ar thermochronometry measurements on the 3.7-billion-year-old mare basalt sample 10020. This sample contains a high-coercivity magnetization acquired in a stable field of at least ~12 microteslas. These data extend the known lifetime of the lunar dynamo by 500 million years. Such a long-lived lunar dynamo probably required a power source other than thermochemical convection from secular cooling of the lunar interior. The inferred strong intensity of the lunar paleofield presents a challenge to current dynamo theory.  相似文献   

Interactive effects of nocturnal transpiration and climate change on the root hydraulic redistribution and carbon and water budgets of southern United States pine plantations     

Domec JC  Ogée J  Noormets A  Jouangy J  Gavazzi M  Treasure E  Sun G  McNulty SG  King JS 《Tree physiology》2012,32(6):707-723

Deep root water uptake and hydraulic redistribution (HR) have been shown to play a major role in forest ecosystems during drought, but little is known about the impact of climate change, fertilization and soil characteristics on HR and its consequences on water and carbon fluxes. Using data from three mid-rotation loblolly pine plantations, and simulations with the process-based model MuSICA, this study indicated that HR can mitigate the effects of soil drying and had important implications for carbon uptake potential and net ecosystem exchange (NEE), especially when N fertilization is considered. At the coastal site (C), characterized by deep organic soil, HR increased dry season tree transpiration (T) by up to 40%, and such an increase affected NEE through major changes in gross primary productivity (GPP). Deep-rooted trees did not necessarily translate into a large volume of HR unless soil texture allowed large water potential gradients to occur, as was the case at the sandy site (S). At the Piedmont site (P) characterized by a shallow clay-loam soil, HR was low but not negligible, representing up to 10% of T. In the absence of HR, it was predicted that at the C, S and P sites, annual GPP would have been diminished by 19, 7 and 9%, respectively. Under future climate conditions HR was predicted to be reduced by up to 25% at the C site, reducing the resilience of trees to precipitation deficits. The effect of HR on T and GPP was predicted to diminish under future conditions by 12 and 6% at the C and P sites, respectively. Under future conditions, T was predicted to stay the same at the P site, but to be marginally reduced at the C site and slightly increased at the S site. Future conditions and N fertilization would decrease T by 25% at the C site, by 15% at the P site and by 8% at the S site. At the C and S sites, GPP was estimated to increase by 18% and by >70% under future conditions, respectively, with little effect of N fertilization. At the P site, future conditions would stimulate GPP by only 12%, but future conditions plus N fertilization would increase GPP by 24%. As a consequence, in all sites, water use efficiency was predicted to improve dramatically with future conditions. Modeling the effect of reduced annual precipitation indicated that limited water availability would decrease all carbon fluxes, including NEE and respiration. Our simulations highlight the interactive effects of nutrients and elevated CO(2), and showed that the effect of N fertilization would be greater under future climate conditions.  相似文献   

Risk factors associated with transmission of Mycobacterium avium subsp. paratuberculosis to calves within dairy herd: a systematic review     

Doré E  Paré J  Côté G  Buczinski S  Labrecque O  Roy JP  Fecteau G 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2012,26(1):32-45

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