X-RAY DIFFRACTION STUDIES OF FLIGHT MUSCLE OF MANDUCA

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 鹰蛾Manduca sexta的飞行肌肉很有趣，原因有两个：1)它的主动力/伸展曲线与哺乳动物的心肌非常相似；2)背腹方向有惊人的温度梯度，平均相差8.8摄氏度(最大为10摄氏度；n=7)。众所周知，在肌肉收缩过程中，由于化学能转化为机械功而产生热量。许多飞行肌肉活跃的大型昆虫利用这种副产品来提高飞行肌肉的温度，从而在飞行过程中实现更高的机械功率输出。收缩热产生与对流和辐射热损失相结合必然会导致温度梯度，但这种梯度的功能后果尚不清楚。因为肌肉的力量产生依赖于温度，所以经历较低温度的亚单位可能会与经历较高温度的亚单位功能不同。温度梯度是否必然意味着肌肉不同部位纤维之间的基本结构差异？测试一种假设，即冷肌中的交叉桥不会像热肌肉中那样迅速分离。即脱附率是一种与温度有关的现象.横桥的附着/剥离速率还将取决于给定肌肉中的弹性存储。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The flight muscle of the Hawkmoth Manduca sexta is interesting for two reasons 1) It's active force/extension curve in very similar to mammalian cardiac muscle 2) there is an astonishing temperature gradient in the dorso-ventral direction, with a mean difference of 8.8 ¿C (a max of 10 ¿C; n = 7) across 5 mm. It is known that during muscle contraction, heat is produced as chemical energy is converted into mechanical work. Many large insects with active flight muscles use this byproduct to elevate flight muscle temperature, thereby achieving higher mechanical power output during flight. Contractile heat production paired with convective and radiative heat loss necessarily lead to a temperature gradient, but the functional consequences of such a gradient remain unknown. Because force generation of muscle depends on temperature, subunits experiencing lower temperatures could function differently than those at higher temperatures. Do thermal gradients necessarily imply fundamental structural differences between fibers in different parts of muscle? Test the hypothesis that crossbridges in cold muscle do not detach rapidly as rapidly as in hot muscle. i.e. detachment rate a temperature dependent phenomenon. The attachment/detachment rates of crossbridges will also depend on elastic storage in a given muscle.