Influence of nitrogen and sulfur on biomass production and carotenoid and glucosinolate concentrations in watercress (Nasturtium officinale R. Br.)     

Kopsell DA  Barickman TC  Sams CE  McElroy JS 《Journal of agricultural and food chemistry》2007,55(26):10628-10634

Watercress (Nasturtium officinale R. Br.) is a perennial herb rich in the secondary metabolites of glucosinolates and carotenoids. 2-phenethyl isothiocyanate, the predominate isothiocyanate hydrolysis product in watercress, can reduce carcinogen activation through inhibition of phase I enzymes and induction of phase II enzymes. Sulfur (S) and nitrogen (N) have been shown to influence concentrations of both glucosinolates and carotenoids in a variety of vegetable crops. Our research objectives were to determine how several levels of N and S fertility interact to affect watercress plant tissue biomass production, tissue C/N ratios, concentrations of plant pigments, and glucosinolate concentrations. Watercress was grown using nutrient solution culture under a three by three factorial arrangement, with three S (8, 16, and 32 mg/L) and three N (6, 56, and 106 mg/L) fertility concentrations. Watercress shoot tissue biomass, tissue %N, and tissue C/N ratios were influenced by N but were unaffected by changes in S concentrations or by the interaction of NxS. Tissue pigment concentrations of beta-carotene, lutein, 5,6-epoxylutein, neoxanthin, zeaxanthin, and the chlorophyll pigments responded to changes in N treatment concentrations but were unaffected by S concentrations or through N x S interactions. Watercress tissue concentrations of aromatic, indole, and total glucosinolate concentrations responded to changes in N treatments; whereas aliphatic, aromatic, and total glucosinolates responded to changes in S treatment concentrations. Individual glucosinolates of glucobrassicin, 4-methoxyglucobrassicin, and gluconasturriin responded to N fertility treatments, while gluconapin, glucobrassicin, and gluconasturiin responded to changes in S fertility concentrations. Increases in carotenoid and glucosinolate concentrations through fertility management would be expected to influence the nutritional value of watercress in human diets.  相似文献   

Influence of orally administered CpG-ODNs on the humoral response to bovine serum albumin (BSA) in chickens     

Ameiss KA  El Attrache J  Barri A  McElroy AP  Caldwell DJ 《Veterinary immunology and immunopathology》2006,110(3-4):257-267

Synthetic oligodeoxynucleotides containing CpG motifs (CpG-ODNs) have been reported to be effective mucosal adjuvants in mice when given orally. Studies on their effectiveness in chickens are currently very limited. This study investigated whether CpG-ODNs could adjuvant the immune response to BSA when given orally to a commercial line of SCWL chickens. In two experiments, performed over time, chickens were given selected concentrations of CpG-ODNs with BSA followed by 6 consecutive days of ad libitum access to drinking water containing 1.4 mg/ml BSA. Serum responses, and in some cases intestinal specific antibodies, were measured out to 33 days post-immunization. Birds receiving a single dose of CpG-ODN had consistently higher IgG, IgM, and IgA titers in the serum, dependent upon dose, and in specific areas of the intestine when compared to the non-immunized and BSA only groups. These findings suggest that a single oral CpG-ODN administration can accelerate the kinetics of antigen specific antibodies of all three isotypes in commercial-strain chickens immunized via the drinking water using common protein antigen.  相似文献   

Influence of diet, phytase, and incubation time on calcium and phosphorus solubility in the gastric and small intestinal phase of an in vitro digestion assay     

Walk CL  Bedford MR  McElroy AP 《Journal of animal science》2012,90(9):3120-3125

To determine the influence of incubation time, diet, and particle size on Ca and P solubility in vitro, experimental diets were formulated to contain 0.89% Ca and 0.40% available P (positive control; PC) or 0.76% Ca and 0.27% available P (negative control; NC). The PC was supplemented with 0 or 1,000 phytase units (FTU) of microbial phytase/kg and the NC with 0, 1,000, or 5,000 FTU/kg diet of microbial phytase for a total of 5 experimental diets. In Exp. 1, diets were exposed to simulated gastric digestion containing HCl and pepsin for 42 min, or a small intestinal digestion phase containing NaHCO(3) and pancreatin for 60 min. In Exp. 2, diets were ground to pass a 1- or 2-mm screen and exposed to gastric digestion for 5, 10, or 20 min. Phosphorus and Ca solubility were similarly influenced by diet and digestion phase (Exp. 1), and there was no interaction. Phytase supplementation improved (P < 0.001) Ca and P solubility in both the PC and NC diets (Exp. 1) and increased P (P < 0.001) and Ca (P < 0.001) solubility in the gastric phase of the in vitro digestion model (Exp. 2). Phytase continued to release P in the gastric test over time, which resulted in a diet × time interaction (P < 0.05). Calcium solubility reached an asymptote at 5 min and both Ca and P solubility was reduced (P < 0.05) in diets ground to pass a 2 mm screen compared with diets ground to pass a 1-mm screen. In addition, P and Ca solubility did not change over time in diets not supplemented with phytase. In conclusion, phytase or particle size altered the kinetics of Ca and P release in a non-parallel fashion, which may be associated with the precipitation of Ca with phytate and the sequential dephosphorylation of phytate by a microbial 6-phytase. In the presence of phytase, considerable Ca and P hydrolysis occurred within 5 min of a simulated gastric digestion. However, the solubility of Ca and P reached a plateau in the gastric phase of digestion and no further improvements in solubility are apparent in the small intestine. Therefore, absorption of Ca and P may be complicated by conditions within the gastrointestinal tract, particle size, precipitation with anti-nutrients, and differential rates of delivery to the small intestine.  相似文献   

Distribution of lesions in fetal brains following experimental infection of pregnant sheep with Toxoplasma gondii     

O'Donovan J  Proctor A  Gutierrez J  Worrell S  Nally J  Marques P  Brady C  McElroy M  Sammin D  Buxton D  Maley S  Bassett H  Markey B 《Veterinary pathology》2012,49(3):462-469

Six ovine fetal brains were harvested 33 to 35 days postchallenge from 5 ewes, each of which was given 3000 Toxoplasma gondii oocysts on day 90 of pregnancy. Histopathologic examination of transverse sections taken at 13 levels in the fetal brains revealed the presence of toxoplasmosis-related lesions in all 6 brains. However, lesions were not randomly distributed (P = .007); they were most numerous at the level of the optic tract, the rostral margin of the pons, and 4 mm caudal to the ansate sulcus and were absent in all sections at the level of the caudal cerebellum. Lesion distribution may be due to hemodynamic factors, differences in the expression of endothelial surface receptor molecules at the level of the blood-brain barrier, or the presence of localized permissive/inhibitory factors within the brain. The results have implications for the selection of areas of brain from aborted ovine fetuses to be examined histopathologically for laboratory diagnosis.  相似文献   

Electron temperatures and densities in the venus ionosphere: pioneer venus orbiter electron temperature probe results     

Brace LH  Theis RF  Krehbiel JP  Nagy AF  Donahue TM  McElroy MB  Pedersen A 《Science (New York, N.Y.)》1979,203(4382):763-765

Altitude profiles of electron temperature and density in the ionosphere of Venus have been obtained by the Pioneer Venus orbiter electron temperatutre probe. Elevated temperatutres observed at times of low solar wind flux exhibit height profiles that are consistent with a model in which less than 5 percent of the solar wind energy is deposited at the ionopause and is conducted downward through an unmagnetized ionosphere to the region below 200 kilomneters where electron cooling to the neutral atmosphere proceeds rapidly. When solar wind fluxes are higher, the electron temperatures and densities are highly structured and the ionopause moves to lower altitudes. The ionopause height in the late afternoon sector observed thus far varies so widely from day to (day that any height variation with solar zenith angle is not apparent in the observations. In the neighborhood of the ionopause, measuremnents of plasma temperatures and densities and magnetic field strength indicate that an induced magnetic barrier plays an important role in the pressure transfer between the solar wind and the ionosphere. The bow, shock is marked by a distinct increase in electron current collected by the instrument, a featutre that provides a convenient identification of the bow shock location.  相似文献   

Isotopic composition of the martian atmosphere     

McElroy MB  Yung YL 《Science (New York, N.Y.)》1976,194(4260):68-70

Results from the neutral mass spectrometer carried on the aeroshell of Viking 1 show evidence for NO in the upper atmosphere of Mars and indicate that the isotopic composition of carbon and oxygen is similar to that of Earth. Mars is enriched in (15)N relative to Earth by about 75 percent, a consequence of escape that implies an initial abundance of nitrogen equivalent to a partial pressure of at least 2 millibars. The initial abundance of oxygen present either as CO(2) or H(2)O must be equivalent to an exchangeable atmospheric pressure of at least 2 bars in order to inhibit escape-related enrichment of (18)O.  相似文献   

Protein Structure and Function during Differentiation     

McElroy WD 《Science (New York, N.Y.)》1963,140(3574):1427-1430

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Colossal Magnetoresistance Without Mn3+/Mn4+ Double Exchange in the Stoichiometric Pyrochlore Tl2Mn2O7     

MA Subramanian  BH Toby  AP Ramirez  WJ Marshall  AW Sleight  GH Kwei 《Science (New York, N.Y.)》1996,273(5271):81-84

Structural analysis from powder neutron and single-crystal x-ray diffraction data for a sample of the Tl2Mn2O7 pyrochlore, which exhibits colossal magnetoresistance (CMR), shows no deviations from ideal stoichiometry. This analysis gives an Mn-O distance of 1.90 angstroms, which is significantly shorter than the Mn-O distances (1.94 to 2.00 angstroms) observed in phases based on LaMnO3 perovskites that exhibit CMR. Both results in Tl2Mn2O7 indicate oxidation states very close to Tl23+Mn24+O7. Thus, Tl2Mn2O7 has neither mixed valence for a double-exchange magnetic interaction nor a Jahn-Teller cation such as Mn3+, both of which were thought to have an important function in CMR materials. An alternate mechanism for CMR in Tl2Mn2O7 based on magnetic ordering driven by superexchange and strong spin-fluctuation scattering above the Curie temperature is proposed here.  相似文献   

SUCCESSFUL REARING OF A SECOND GENERATION OF MICE ON AN ARTIFICIAL DIET     

Rogers LK  McElroy LW  Cowgill GR 《Science (New York, N.Y.)》1942,95(2460):203-204

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Analgesic therapy of beak-trimmed chickens     

PC GLATZ  LB MURPHY  AP RESTON 《Australian veterinary journal》1992,69(1):18-18

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