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1.
Differences in chemical composition of plants grown at constant relative growth rates with stable mineral nutrition 总被引:11,自引:0,他引:11
R. H. Waring A. J. S. McDonald S. Larsson T. Ericsson A. Wiren E. Arwidsson A. Ericsson T. Lohammar 《Oecologia》1985,66(2):157-160
Summary Leaf chemistry of a willow clone (Salix aquatica Smith) differed significantly when grown at constant relative growth rates depending upon the relative availability of nutrients and light. Concentration of amino acids and nitrate were high in plants grown with a relative surplus of nutrients. Concentrations of starch, tannin, and lignin, on the other hand, were high in plants grown with a relative surplus of carbon. Photosynthetic rates, expressed per unit leaf area, were similar when plants were grown under high light conditions, regardless of nutrient availability. Dark respiration was much higher in plants supplied with abundant nutrients than in those with a more limited supply, reflecting differences in nitrogen concentration of the tissue. The experimental approach allows plants to be grown to a standard size with differing, but highly uniform chemistry. Plants grown in such a manner may provide good experimental material to evaluate interactions between herbivores or pathogens and their hosts. 相似文献
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J C McDonald 《BMJ (Clinical research ed.)》1981,282(6257):83-4,88
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R McDonald J Hegenauer A Sucec P Saltman 《European journal of applied physiology and occupational physiology》1984,52(4):414-419
The effects of iron deficiency and endurance training on muscle myoglobin (Mb), body weights, and blood lactic acid concentration were studied in rats. Fifty animals were divided into four groups: anemic trained (AT), normal trained (NT), anemic sedentary (AS), and normal sedentary (NS). Following 5 weeks of dietary control, the mean hemoglobin values for the AT and AS rats were 0.013 +/- 0.002 mmol X l-1 (8.7 +/- 1.4 g X dl-1) and 0.014 +/- 0.003 mmol X l-1 (9.2 +/- 1.7 g X dl-1) respectively, and did not significantly change throughout the study. AT and NT rats were run on a motor driven treadmill 4 days/week for 6 weeks up to a pre-established time of 90 min. Following the training, body weights of the AT (157 +/- 13 g) and NT (153 +/- 13 g) rats were lower than their respective sedentary groups AS (172 +/- 9 g) and NS (176 +/- 15 g). Resting blood lactic acid concentration following training was lower in both trained groups, AT (3.3 +/- 2.0 mM) and NT (2.3 +/- 1.9 mM) compared to AS (8.2 +/- 2.6 mM) and NS (3.8 +/- 1.6 mM). Training increased Mb concentration in hearts of both the anemic and normal trained groups (AT, 0.66 +/- 0.13 mg X g-1; NT, 0.95 +/- 0.08 mg X g-1) compared to the sedentary groups (AS, 0.44 +/- 0.08 mg X g-1; NS, 0.70 +/- 0.13 mg X g-1). Only the AT rats showed an increase in skeletal muscle Mb. This study provides evidence that myoglobin may limit aerobic metabolism. 相似文献
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McDonald LC McFeeters RF Daeschel MA Fleming HP 《Applied and environmental microbiology》1987,53(6):1382-1384
A medium was developed for the differential enumeration of homofermentative and heterofermentative lactic acid bacteria. Essential components of the medium included fructose (14 mM), KH(2)PO(4) (18 mM), bromcresol green (as a pH indicator), and other nutrients to support growth. In agar medium, homofermentative colonies were blue to green, while heterofermentative colonies remained white. A total of 21 Lactobacillus, Pediococcus, Leuconostoc, and Streptococcus species were correctly classified with the medium. 相似文献
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Electrophoretic and immunochemical study of the lipopolysaccharides produced by chemostat-grown Escherichia coli O157 总被引:3,自引:0,他引:3
Two chemically different O-polysaccharides, a low molecular mass form of LPS and core LPS produced by chemostat-grown E. coli O157, were analysed by SDS-PAGE, silver staining and immunoblotting. The reactivities of the different O-polysaccharides with antisera prepared against E. coli O157 grown in batch culture, Salmonella O30 or Brucella abortus were very similar, showing that the O-polysaccharides share at least some antigenic determinants. The reactions of the low molecular mass LPS with the antisera indicated it was semi-rough LPS having one repeat unit of the O-polysaccharide attached to core LPS. 相似文献
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