Ecological variables affecting predatory success in Myxococcus xanthus
Ecological variables affecting predatory success in Myxococcus xanthus
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DOI：
10.1007/s00248-006-9111-3
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发表时间：
2007-05-01
影响因子：
3.6
通讯作者：
Velicer, Gregory J.
中科院分区：
文献类型：
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作者：
Hillesland, Kristina L.;Lenski, Richard E.;Velicer, Gregory J.
微生物捕食者的摄食效率取决于各种猎物种类的可获得性和非生物变量。黄色粘球菌是一种细菌捕食者，它通过滑动运动寻找微生物猎物，然后用分泌的化合物杀死并裂解猎物。我们操纵了三个生态变量来考察它们对黄曲霉捕食行为的影响，以更好地了解它的行为及其对猎物种群的影响。实验旨在确定表面的坚固性(硬琼脂和软琼脂)、猎物斑块的密度(1厘米和2厘米网格)和猎物类型(革兰氏阳性黄色微球菌和革兰氏阴性大肠杆菌)如何影响黄色微球菌对捕食性蜂群和猎物的杀灭。猎物散布在缓冲的琼脂表面上。与软琼脂表面或低密度斑块排列相比，当斑块密集排列在硬琼脂表面时，黄花草蜂群攻击的猎物斑块比例更大。这些生态变量对斑块内个体猎物的杀伤率没有显著影响，尽管一些幸存的猎物在软琼脂上比在硬琼脂上更有可能被恢复。这些结果表明，无论表面如何，黄色分枝杆菌都能迅速杀死附近的大多数大肠杆菌或黄分枝杆菌。然而，黄曲霉寻找这些猎物斑块的能力受到表面硬度、猎物斑块密度和猎物种类的影响。
The feeding efficiency of microbial predators depends on both the availability of various prey species and abiotic variables. Myxococcus xanthus is a bacterial predator that searches for microbial prey by gliding motility, and then kills and lyses its prey with secreted compounds. We manipulated three ecological variables to examine their effects on the predatory performance of M. xanthus to better understand its behavior and how it affects prey populations. Experiments were designed to determine how surface solidity (hard vs soft agar), density of prey patches (1 vs 2 cm grids), and type of prey (Gram-positive Micrococcus luteus vs Gram-negative Escherichia coli) affect predatory swarming and prey killing by M. xanthus. The prey were dispersed in patches on a buffered agar surface. M. xanthus swarms attacked a greater proportion of prey patches when patches were densely arranged on a hard-agar surface, compared with either soft-agar surfaces or low-patch-density arrangements. These ecological variables did not significantly influence the rate of killing of individual prey within a patch, although a few surviving prey were more likely to be recovered on soft agar than on hard agar. These results indicate that M. xanthus quickly kills most nearby E. coli or M. luteus regardless of the surface. However, the ability of M. xanthus to search out patches of these prey is affected by surface hardness, the density of prey patches, and the prey species.