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591.
Changes in antibiotic sensitivity and cell surface hydrophobicity in Escherichia coli injured by heating, freezing, drying or gamma radiation 总被引:6,自引:0,他引:6
B.M. Mackey 《FEMS microbiology letters》1983,20(3):395-399
Abstract Escherichia coli cells exposed to mild heating, freezing and thawing, drying or γ-radiation were sensitised to hydrophobic antibiotics and sodium deoxycholate but not to small hydrophilic antibiotics. These stress treatments also caused increases in cell surface hydrophobicity broadly reflecting the degree of sensitivity to hydrophobic antibiotics. 相似文献
592.
A trade-off between scale and precision in resource foraging 总被引:21,自引:0,他引:21
Summary There is widespread uncertainty about the nature and role of morphological plasticity in resource competition in plant communities.
We have assayed the foraging characteristics of leaf canopies and root systems of eight herbaceous plants of contrasted ecology
using new techniques to create controlled patchiness in light and mineral nutrient supply. The results are compared with those
of a conventional competition experiment. Measurements of dry matter partitioning and growth in patchy conditions indicate
a consistent positive association between the foraging characteristics of roots and shoots, supporting the hypothesis of strong
interdependence of competitive abilities for light and mineral nutrients. Differences are identified in the abilities of dominant
and subordinate plants to forage on coarse and fine scalcs. It is suggested that a trade-off exists in the scale (“high” in
dominants) and precision (high in subordinates) with which resources are intercepted and that this trade-off contributes to
diversity in communities of competing plants. 相似文献
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Cheryl A. Krone Paul A. Robisch Karen L. Tilbury John E. Stein Elizabeth A. Mackey Paul R. Becker Todd M. O'hara L. Michael Philo 《Marine Mammal Science》1999,15(1):123-142
Livers from 20 bowhead whales taken in subsistence hunts at Barrow, Alaska, were analyzed for essential and non-essential elements. Concentrations of essential elements were similar to those found in other cetaceans. Non-essential element concentrations were generally comparable to other baleen whales and very low compared to most odontocetes. One deviation from this pattern was a relatively high level of hepatic cadmium that may be related to specific dietary factors of this krill-dependent species. No sex-related differences were found in element concentrations. Hepatic cadmium and mercury increased with animal length, and significant positive interelement correlations were found between copper/zinc and mercury/selenium. We found a mercury-toselenium ratio much lower (1:40) than the frequently reported ratio of one to one. The data suggest that further studies of the postulated mercurydetoxifying role of selenium are warranted. 相似文献
596.
The exosporium of Clostridium pasteurianum 总被引:2,自引:0,他引:2
597.
The fluorogenic redox indicator 5-cyano-2,3-ditolyltetrazolium chloride (CTC) was compared with the chromogenic p -iodonitrotetrazolium violet (INT) and conventional methods to assess cellular viability. Mild heat treatment was used as a well-controlled method for producing non-viable and sub-lethally injured cells. CTC gave an underestimation of the viability of Listeria monocytogenes cells when compared with classical plating methods whereas INT gave an overestimation. However, CTC proved to be a sensitive indicator of uninjured cells. The difference between the total count and the CTC count was equivalent to the injured cell population. The fluorescent formazan formed on reduction ofCTC was readily detected with a charge coupled device and cells enumerated automatically using image analysis. 相似文献
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