Transgenerational phenotypic plasticity: Cardiorespiratory physiology of the parthenogenetic marbled crayfish as a model system

该项目的目的是研究心脏呼吸系统生理参数的表型可塑性(即基于同一基因的不同表型的形成)。有人假设，表型可塑性可能是进化适应发生之前的一种临时解决方案。因此，它可以被视为一种重要的进化现象。作为模式系统，将研究孤雌生殖大理石小龙虾心肺系统的生理学。这个物种只有雌性存在，产生的后代基因相同，因此非常适合研究表型可塑性。为了触发表型可塑性的影响，个体在发育早期会暴露于环境应激源(低氧、温度升高、多环芳香碳水化合物污染)。在以后的阶段，将测量生理参数(心率、每搏量、心输出量、氧耗量)，并与对照组(在最佳条件下饲养)进行比较。心率、每搏量和心输出量将使用视频序列来确定。耗氧量的测量将通过带有光学荧光氧气传感系统的特殊测量室进行。除了表型可塑性的代内效应外，还将研究塑料生理参数的跨代遗传(由于对其他物种的这种影响的了解，预计会有这种遗传)。为此，将在子代中测量相同的生理参数，这些子代(不包括母亲个体)本身没有暴露在环境应激源中。应该证明，心肺生理的表型可塑性是一种有趣的现象，可以导致对快速变化的环境条件的适应。

The aim of this project is to investigate phenotypic plasticity (i.e. the formation of different phenotypes based on the same genotype) of physiological parameters of the cardiorespiratory system. It is hypothesized that phenotypic plasticity might represent an interim solution until evolutionary adaptation can take place. Thus, it can be regarded as important evolutionary phenomenon. As a model system, physiology of the cardiorespiratory system of the parthenogenetic marbled crayfish, Procambarus fallax f. virginalis, will be studied. This species, of which only females exist, produces genetically identical offspring and thus is well suited for studies on phenotypic plasticity. To trigger effects of phenotypic plasticity, individuals will be exposed to environmental stressors (hypoxia, increased temperature, pollution with polycyclic aromatic carbohydrates) during early development. In later stages, physiological parameters (heart rate, stroke volume, cardiac output, oxygen consumption) will be measured and compared to a control group (raised under optimal conditions). Heart rate, stroke volume and cardiac output will be determined using video sequences. Measurement of oxygen consumption will be done with special measurement chambers with an optical fluorescence oxygen-sensing system. Beside intragenerational effects of phenotypic plasticity, transgenerational inheritance of plastic physiological parameters (as is expected due to knowledge on such effects in other species) will be studied. To that end, the same physiological parameters will be measured in the offspring, which (other than the mother individuals) have not been exposed to the environmental stressors themselves. It shall be shown that phenotypic plasticity of cardiorespiratory physiology is an interesting phenomenon that can lead to adaptation to fast change of environmental conditions.