Model systems for environmental signaling
Model systems for environmental signaling
复制标题
DOI：
10.1093/icb/45.4.605
复制
发表时间：
2005-09-01
影响因子：
2.6
通讯作者：
Bridge, DM
中科院分区：
文献类型：
--
作者：
Blackstone, NW;Bridge, DM
对动物环境信号传导的研究主要集中在时间和表型反应相对受限的生物体上。在这方面，现有的模型动物（例如“蠕虫和苍蝇”）尤其极端。这些动物响应环境信号而改变其形态的能力相对较小。因此，它们表现出很小的表型可塑性。另一方面，基础后生动物对环境信号表现出相对不受限制的反应，因此可能提供更普遍的见解，因为这些限制可能是动物进化过程中衍生的特征。这种增强的表型可塑性可能是由于对环境信号的更大敏感性，或更多的合适靶细胞，或两者兼而有之。对刺胞动物已知的环境信号通路成分的检查揭示了与经过充分研究的模型动物的许多相似之处。然而，除了这些元素之外，宏观基础后生动物（例如海绵和刺胞动物）通常表现出整合环境信息的系统级能力。在刺胞动物中，胃肠血管系统以这种方式发挥作用，通过其整个生物体的功能产生局部信号模式（例如压力、剪切力和活性氧）。含有大量富含线粒体的上皮肌肉细胞的组织收缩区域在这方面可能特别重要，在功能和信号传导方面发挥作用。虽然动物循环系统的进化通常被认为是减轻表面与体积的限制，但此类系统还具有增强较大生物体快速有效地响应环境信号的能力的优点。还列举和讨论了与对环境信号相对不受约束的反应相关的动物的更一般特征（例如，生命周期各个阶段的活性干细胞）。
Studies of environmental signaling in animals have focused primarily on organisms with relatively constrained responses, both temporally and phenotypically. In this regard, existing model animals (e.g., "worms and flies") are particularly extreme. Such animals have relatively little capacity to alter their morphology in response to environmental signals. Hence, they exhibit little phenotypic plasticity. On the other hand, basal metazoans exhibit relatively unconstrained responses to environmental signals and may thus provide more general insight, insofar as these constraints are likely traits derived during animal evolution. Such enhanced phenotypic plasticity may result from greater sensitivity to environmental signals, or greater abundance of suitable target cells, or both. Examination of what is known of the components of environmental signaling pathways in cnidarians reveals many similarities to well-studied model animals. In addition to these elements, however, macroscopic basal metazoans (e.g., sponges and cnidarians) typically exhibit a system-level capability for integrating environmental information. In cnidarians, the gastrovascular system acts in this fashion, generating local patterns of signaling (e.g., pressure, shear, and reactive oxygen species) via its organism-wide functioning. Contractile regions of tissue containing concentrations of mitochondrion-rich, epitheliomuscular cells may be particularly important in this regard, serving in both a functional and a signaling context. While the evolution of animal circulatory systems is usually considered in terms of alleviating surface-to-volume constraints, such systems also have the advantage of enhancing the capacity of larger organisms to respond quickly and efficiently to environmental signals. More general features of animals that correlate with relatively unconstrained responses to environmental signals (e.g., active stem cells at all stages of the life cycle) are also enumerated and discussed.