Quantitative aspects of D- and L-tryptophan utilization by the young pig   总被引：1，自引：0，他引：1  

D H Baker  N K Allen  J Boomgaardt  G Graber  H W Norton 《Journal of animal science》1971,33(1):42-46

  相似文献   

Effects on plasma endotoxin and eicosanoid concentrations and serum cytokine activities in horses competing in a 48-, 83-, or 159-km endurance ride under similar terrain and weather conditions     

Barton MH  Williamson L  Jacks S  Norton N 《American journal of veterinary research》2003,64(6):754-761

OBJECTIVE: To determine plasma endotoxin concentration in horses competing in a 48-, 83-, or 159-km endurance race and its importance with regard to physical, hematologic, or serum and plasma biochemical variables. ANIMAL: 3 horses. PROCEDURE: Weight and rectal temperature measurements and blood samples were obtained before, during, and after exercise. Blood samples were analyzed for plasma endotoxin concentration; serum antiendotoxin antibody titers; thromboxane B2 (TxB2) and 6-keto-prostaglandin F1alpha (PGF1alpha) concentrations; tumor necrosis factor alpha (TNFalpha) and interleukin-6 (IL-6) activities; WBC, plasma protein, lactate, serum electrolyte, and calcium concentrations; PCV; and creatine kinase activity. RESULTS: Detection of plasma endotoxin increased during exercise for horses competing at all distances but occurred more frequently in the 48- and 83-km groups. Plasma lactate concentration was significantly greater when endotoxin was concurrently detected. Endotoxin in plasma was not significantly associated with success of race completion. Plasma TxB2 and PGF1alpha concentrations and serum IL-6 activity significantly increased with exercise. Horses that had an excellent fitness level (as perceived by their owners) had greater decreases in serum antiendotoxin antibody titers during exercise than did horses perceived as less fit. In horses with better finish times, TxB2 and PGF1alpha concentrations were significantly greater and TNFalpha activity was significantly less than that of slower horses. CONCLUSIONS AND CLINICAL RELEVANCE: Endotoxemia developed during endurance racing, but was significantly correlated with increased plasma lactate concentration and not with other variables indicative of endotoxemia. Plasma TxB2 and PGF1alpha concentrations and serum TNFalpha activity may be associated with performance success.  相似文献   

Antimicrobial-induced endotoxin and cytokine activity in an in vitro model of septicemia in foals     

Bentley AP  Barton MH  Lee MD  Norton NA  Moore JN 《American journal of veterinary research》2002,63(5):660-668

OBJECTIVE: To determine which antimicrobials that are used to treat neonatal foals with septicemia attributable to Escherichia coli will minimize endotoxin release from bacteria and subsequent activity of inflammatory mediators while maintaining bactericidal efficacy. SAMPLE POPULATION: Blood samples from 10 healthy foals. PROCEDURE: Escherichia coli isolates A and B were isolated from 2 septicemic foals, and minimal inhibitory concentrations (MIC) were determined for 9 antimicrobials. Five of these antimicrobials were tested in vitro at 2 and 20 times their respective MIC. Whole blood or mononuclear cells grown in tissue-culture media were incubated with 105 colony-forming units of E. coli and each antimicrobial or saline (0.9% NaCl) solution. After 6 hours, number of viable bacteria remaining was determined, and supernatant was tested for endotoxin and tumor necrosis activity. RESULTS: Testing in whole blood was compromised by bactericidal effects of the blood itself. In mononuclear cell suspensions, each antimicrobial significantly reduced the number of viable bacteria to low or undetectable amounts. Antimicrobials did not differ significantly in efficacy of bacterial killing. Amikacin used alone or in combination with ampicillin resulted in significantly less endotoxin activity than did ampicillin, imipenem, or ceftiofur alone. There was a correlation between TNF-alpha and endotoxin activity. CONCLUSIONS AND CLINICAL RELEVANCE: Aminoglycosides appear less likely to induce endotoxemia and TNF-alpha synthesis during bactericidal treatment of E. coli septicemia, compared with beta-lactam antimicrobials. Use of ampicillin, imipenem, or ceftiofur in the treatment of septicemic neonatal foals should be accompanied by appropriate treatment for endotoxemia.  相似文献   

Intra-specific variation of wheat grain quality in response to elevated [CO₂] at two sowing times under rain-fed and irrigation treatments     

Nimesha Fernando  Joe Panozzo  Michael Tausz  Robert M. Norton  Glenn J. Fitzgerald  Samuel Myers  Marc E. Nicolas  Saman Seneweera 《Journal of Cereal Science》2014

In order to investigate the intra-specific variation of wheat grain quality response to elevated atmospheric CO₂ concentration (e[CO₂]), eight wheat (Triticum aestivum L.)cultivars were grown at two CO₂ concentrations ([CO₂]) (current atmospheric, 389 CO₂ μmol mol⁻¹vs. e[CO₂], FACE (Free-Air CO₂ Enrichment), 550  ±  10% CO₂ μmol mol⁻¹), at two water levels (rain-fed vs. irrigated) and at two times of sowing (TOS₁, vs. TOS₂). The TOS treatment was mainly imposed to understand whether e[CO₂] could modify the effects of timing of higher grain filling temperatures on grain quality. When plants were grown at TOS₁, TKW (thousand kernel weight), grain test weight, hardness index, P, Ca, Na and phytate were not significantly changed under e[CO₂]. On the other hand, e[CO₂] increased TKW (16%), hardness index (9%), kernel diameter (6%), test weight (2%) but decreased grain protein (10%) and grain phytate (11%) at TOS₂. In regard to grain Zn, Mn and Cu concentrations and some flour rheological properties, cultivar specific responses to e[CO₂] were observed at both sowing times. Observed genetic variability in response to e[CO₂] in terms of grain minerals and flour rheological properties could be easily incorporated into future wheat breeding programs to enable adaptation to climate change.  相似文献   

Development and evaluation of a rapid absorbed enzyme immunoassay test for the diagnosis of Johne''s disease in cattle   总被引：8，自引：0，他引：8  

JC COX  DP DRANE  SL JONES  S. RIDGE†  AR MILNER† 《Australian veterinary journal》1991,68(5):157-160

An absorbed enzyme immunoassay (EIA) test for Johne's disease in cattle was developed in which absorption of cross-reacting antibodies occurred as a rapid reaction in solution rather than overnight with whole organisms and a subsequent centrifugation step. Total test time was reduced to less than 2 h with a minimum of manipulations. The test was evaluated in cattle herds from Johne's disease-endemic and Johne's disease-free regions of Australia. Specificity was 99.8%. Calculations of sensitivity were affected by the history of the herd under test. However, the EIA detected in excess of 80% of animals before onset of clinical disease and 65% of faecal shedders were EIA positive on, or before, first detection of Mycobacterium paratuberculosis in their faeces. The test should aid epidemiological studies and be a useful tool in the management and control of Johne's disease.  相似文献   

Speciation in the parthenogenetic oribatid mite genus Tectocepheus (Acari, Oribatida) as indicated by molecular phylogeny   总被引：2，自引：0，他引：2  

Michael Laumann  Roy A. Norton  Gerd Weigmann  Stefan Scheu  Mark Maraun  Michael Heethoff 《Pedobiologia》2007,51(2):111-122

Despite the lack of universal concepts for species and speciation, both sexual and asexual organisms are expected to diversify into discrete genotypic and morphological clusters. Species-rich clusters of parthenogenetic oribatid mites likely evolved in the absence of sexual reproduction. We used nucleotide sequences of the large and small rDNA genes (18S and 28S) and the coding genes for heat shock protein 82 (hsp82) and elongation factor-1 alpha (ef-1α) for phylogenetic analyses of three morphotypes of the parthenogenetic oribatid mite genus Tectocepheus. DNA sequence divergences of the different morphotypes were similar to those of sexual species in other organisms. Maximum likelihood analyses of single genes and combined data sets were largely congruent in reconstructing the phylogeny of the Tectocepheus species. The results suggest that the different morphotypes of Tectocepheus indeed evolved in the absence of sexual reproduction, and that Tectocepheus minor, Tectocepheus velatus and Tectocepheus sarekensis are best considered distinct species. Further, the results suggest that 18S rDNA, hsp82 and ef-1α are powerful markers for resolving phylogenetic relationships of oribatid mites. Saturation plots indicated that the D3-region of 28S is much more saturated than all other examined genes. This indicates that the D3-region is unsuitable for resolving ancient splits in oribatid mites.  相似文献   

Randomized intervention analysis of the response of the West Bear Brook Watershed,Maine to chemical manipulation     

Venkatesh Uddameri  Stephen A. Norton  Jeffrey S. Kahl  John P. Scofield 《Water, air, and soil pollution》1995,79(1-4):131-146

A paired watershed manipulation study was conducted to study the qualitative and quantitative impacts of elevated acidic precipitation on the chemistry of soils, soil water, and stream water. The Bear Brook Watershed, Maine (BBWM) is drained by two first order streams, East Bear Brook and West Bear Brook. The streams were chemically and hydrologically monitored for two years (1987–1989) and exhibited similar behavior. The West Bear watershed was then chemically manipulated with the bimonthly addition of (NH₄)₂SO₄ (150 mol ha^?1 per application). To assess whether changes in stream water chemistry occurred following the chemical manipulation, and if so when, Randomized Intervention Analysis (RIA) was performed using time-paired data from the two watersheds. RIA, along with autocorrelation analysis, statistically evaluates the behavior of the various analytes under the influence of artificial acidification and therefore provided an objective basis for determining whether changes in the geochemical behavior of West Bear Brook were temporally associated with the chemical manipulation. RIA analysis using weekly data yielded higher probabilities of stream water chemistry effects being temporally linked with the manipulation than RIA analysis using monthly data. Using monthly data, there is a lower probability that short-term excursions in water chemistry related to hydrology can be detected. According to RIA analysis of weekly data for three years of manipulation (1989–1992), the statistically-determined order of impact on water chemistry was (K⁺, Mg²⁺, Na⁺, Ca²⁺, total Al, pH, SO ₄ ^2? , NO ₃ ^? , DOC)>Si>Cl^?. Autocorrelation analysis indicated that several analytes exhibited increasingly deterministic behavior, including SO ₄ ^2? , base cations, and DOC. Both RIA and autocorrelation analysis indicated no temporal relationship between the manipulation and hydrology.  相似文献   

REMOVING INSECTS FROM GREENHOUSE PLANTS WITHOUT SPRAYING AND WITHOUT INJURY TO THE PLANTS     

Emerson P  Norton JB 《Science (New York, N.Y.)》1918,47(1202):44

  相似文献   

A High-Temperature Electrical Conduction Mechanism in the Lower Mantle Phase (Mg,Fe)1-xO     

DP Dobson  NC Richmond  JP Brodholt 《Science (New York, N.Y.)》1997,275(5307):1779-1781

Measurements of electrical conductivity at high pressure and temperature were taken on the lower mantle phase magnesiowustite with varying Fe3+ content. Although previous measurements at atmospheric pressure suggest Fe2+-Fe3+ hopping (small polaron) as the dominant conductivity mechanism, the present experiments show a change in charge transport mechanism with temperature. The lower temperature measurements are consistent with small polaron conduction, but at higher temperatures, which are more applicable to the lower mantle, a large polaron mechanism is suggested. Because these mechanisms have different temperature and compositional dependencies, this transition has important implications for extrapolation to mantle conditions.  相似文献   

Early tertiary age of pitchstone in the northern black hills, South dakota     

Redden JA  Obradovich JD  Naeser CW  Zartman RE  Norton JJ 《Science (New York, N.Y.)》1983,220(4602):1153-1154

A block of pitchstone in the northern Black Hills, South Dakota, is Paleocene in age, according to potassium-argon dating of biotite and fission-track dating of zircon in the sample. These data invalidate published suggestions that the age is much younger. The pitchstone is not extrusive in its present position but instead is in a volcanic pipe with other fragments that came downward from as much as 1100 meters above the modern surface.  相似文献