Heat flux, oxygen flux, and mitochondrial redox state as a function of oxygen availability and ciliary activity in excised gills of Mytilus edulis.
Heat flux, oxygen flux, and mitochondrial redox state as a function of oxygen availability and ciliary activity in excised gills of Mytilus edulis.
复制标题
贻贝切除鳃中的热通量、氧通量和线粒体氧化还原状态与氧气可用性和纤毛活动的函数关系。
DOI：
10.1002/jez.1402650102
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Gnaiger,E
中科院分区：
文献类型：
--
作者：
Doeller,JE;Kraus,DW;Shick,JM;Gnaiger,E
双壳类软体动物的纤毛鳃位于动物与环境的交界处。纤毛推动水通过鳃，为动物输送氧气和营养。纤毛活性是由动力蛋白ATP酶驱动的，需要ATP的持续供应，其速度足以匹配ATP水解的速度。纤毛鳃中ATP供需平衡的控制，以及这种平衡如何被环境压力改变，目前尚不清楚。在这项初步研究中，研究了贻贝切除鳃的代谢通量对氧气可用性和5 -羟色胺刺激的纤毛活性的响应。热肺活量法同时测定热通量和氧通量。平行实验中，用体内分光光度法测定线粒体细胞色素的氧化还原状态。在4 kPapO2以上，热通量由有氧代谢支持。缺氧热通量小于好氧热通量的5%。在10 μM血清素的存在下，鳃中的热和氧通量几乎增加了一倍；然而，热通量和氧通量以及线粒体细胞色素还原的一半最大po2与对照水平保持不变。在半强度海水中，具有失活纤毛的鳃中，用于热通量和氧通量以及细胞色素还原的一半最大po2值几乎是在全强度海水中的两倍。这些数据表明，当纤毛搏动频率升高时，边界层对氧气输送的限制可能会减少，从而导致细胞内线粒体的氧气通量增加，这与纤毛增加的能量需求相匹配。©1993 Wiley‐Liss, Inc。
The ciliated gill of bivalve molluscs is situated at an interface between animal and environment. Cilia propel water past the gills to deliver oxygen and nutrition to the animal. Ciliary activity is driven by dynein ATPases and requires a continual supply of ATP at a rate sufficient to match the rate of ATP hydrolysis. Control of the balance between ATP supply and demand in the ciliated gill, and how this balance may be altered by environmental stresses, is unknown. In this pilot study, metabolic flux of excised gills from the marine musselMytilus eduliswas examined in response to oxygen availability and to serotonin‐stimulated ciliary activity. Heat flux and oxygen flux were measured simultaneously with calorespirometry. In parallel experiments, the redox state of mitochondrial cytochromes was determined with in vivo spectrophotometry. Above 4 kPapO2, heat flux was supported by aerobic metabolism. Anoxic heat flux was less than 5% of aerobic heat flux. Heat and oxygen fluxes nearly doubled in gills in the presence of 10 μM serotonin; however, half‐maximalpO2for heat and oxygen fluxes and for reduction of mitochondrial cytochromes remained unchanged from control levels. In gills having inactive cilia in half‐strength seawater, half‐maximalpO2for heat and oxygen fluxes and for cytochrome reduction nearly doubled compared with values in full‐strength seawater. These data indicate that limitation to oxygen delivery imposed by boundary layers may be reduced when ciliary beat frequency is elevated, leading to enhanced oxygen flux to intracellular mitochondria which matches the increased energy demand by the cilia. © 1993 Wiley‐Liss, Inc.