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61.
Genetically alterable transport of amethopterin in Diplococcus pneumoniae. II. Impairment of the system associated with various mutant genotypes 总被引:1,自引:2,他引:1 下载免费PDF全文
Six mutations determining resistance to amethopterin were examined for their effects on the active transport of the drug. In strains bearing each of the mutations and exhibiting resistance levels varying from 10- to 100-fold, transport at limiting concentrations of H(3)-amethopterin was reduced from 2.5 to 10 times the rate characteristic of the wild type. Kinetic analysis of transport showed an increase in the value for K(m) of the system in all of the mutants. Values for the wild-type system were 0.9 x 10(-6)m and for the mutants varied between 2.5 x 10(-6)m and 9.0 x 10(-6)m. Values for V(max) were approximately the same for each system. The mutant transport systems also exhibited a shift in pH optimum from near 6.0 (wild-type) to below 5.0. The results were interpreted as an alteration in the binding properties of the permease in the mutant strains. 相似文献
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John J. Sloggett Alexandra Magro François J. Verheggen Jean-Louis Hemptinne William D. Hutchison Eric W. Riddick 《BioControl》2011,56(4):643-661
We review the chemical ecology of the ladybird beetle Harmonia axyridis from the perspective of its invasiveness and the deleterious effects it exerts in the regions it has colonised. We outline
the nature and quantification of its chemical defence, and discuss the protection this provides against natural enemies, particularly
intraguild predators. We consider the role of infochemicals in location of prey, intraspecific communication and intraguild
interactions. We also discuss the role of prey allelochemicals in relation to H. axyridis extreme dietary generalism. Harmonia axyridis poses a number of practical problems for human health and well-being, including “ladybug taint” wine contamination and problems
resulting from large aggregations overwintering in buildings. We consider chemical insights into these issues and, in particular,
how attractants and repellents might help manage H. axyridis populations through a push–pull strategy. We conclude by discussing future perspectives for research. 相似文献
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J. Hutchison 《BMJ (Clinical research ed.)》1887,2(1387):237-238
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Robert Hutchison 《BMJ (Clinical research ed.)》1919,1(3044):535-536
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