Cheaters, diffusion and nutrients constrain decomposition by microbial enzymes in spatially structured environments
Cheaters, diffusion and nutrients constrain decomposition by microbial enzymes in spatially structured environments
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DOI：
10.1111/j.1461-0248.2005.00756.x
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发表时间：
2005-06-01
期刊：
影响因子：
8.8
通讯作者：
Allison, SD
中科院分区：
文献类型：
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作者：
Allison, SD
胞外酶允许微生物从复杂分子中获得碳和营养物质，并催化营养物质矿化的限速步骤。由于调节酶生产的因素知之甚少，我使用模拟模型来研究竞争，营养物质的可用性和空间结构如何影响微生物的生长和酶的合成。在模拟中，产酶微生物与作弊者（不合成酶但吸收产物）竞争，较高的酶成本有利于作弊者，而较低的酶扩散率有利于生产者。作弊者和生产者共存于高度组织化的空间格局在中间酶的成本和扩散率。不同养分输入的模拟表明，由于酶的氮需求化学计量比（C：N = c. 3.5：1）。这些结果表明，来自骗子的竞争，缓慢的扩散和氮限制可能会限制微生物觅食和复杂化合物在自然环境中的酶促分解。
Extracellular enzymes allow microbes to acquire carbon and nutrients from complex molecules and catalyse the rate-limiting step in nutrient mineralization. Because the factors regulating enzyme production are poorly understood, I used a simulation model to examine how competition, nutrient availability and spatial structure affect microbial growth and enzyme synthesis. In simulations where enzyme-producing microbes competed with cheaters (who do not synthesize enzymes but take-up product), higher enzyme costs favoured cheaters, while lower rates of enzyme diffusion favoured producers. Cheaters and producers coexisted in highly organized spatial patterns at intermediate enzyme costs and diffusion rates. Simulations with varying nutrient inputs showed that nitrogen supply can limit carbon mineralization, microbial growth and enzyme production because of the nitrogen-demanding stoichiometry of enzymes (C : N = c. 3.5 : 1). These results suggest that competition from cheaters, slow diffusion and nitrogen limitation may constrain microbial foraging and the enzymatic decomposition of complex compounds in natural environments.