Colgate University, Department of Biology, Hamilton, NY, 13346, USA.
Colgate University, Department of Biology, Hamilton, NY, 13346, USA.
J Therm Biol. 2021 Aug;100:103050. doi: 10.1016/j.jtherbio.2021.103050. Epub 2021 Jul 10.
Efforts to determine physiological traits that may render species resilient or susceptible to changing global temperatures have accelerated in recent years. Temperature is of critical importance to biological function; thus, climate change has the potential to severely affect all levels of biological organization in many species. For example, increases in environmental temperatures may alter muscle structure and function in birds. Myonuclear domain (MND), an under-studied aspect of avian muscle physiology that changes in response to thermal stress, is defined as the amount of cytoplasm within a muscle fiber that each nucleus is responsible for servicing. Here, we used two random bred lines of Japanese quail (Coturnix japonica) representing examples of control and fast growth rates. We used a factorial design to administer four treatment combinations to each line - an initial period of either heat-stress acclimation (Acclimation) or no acclimation (Not acclimated) followed by either a heat-stress challenge (HS) or no challenge (NC) after week 8 of age - to determine the effects of thermal acclimation and acute thermal stress on quail MND. We found a significant interaction between line * final treatment with fast-growing, HS birds demonstrating the lowest numbers of nuclei per mm of fiber, and Acclimated control-growing birds showing the highest numbers of nuclei per mm of fiber. There was a significant effect of line on MND with the fast-growing line having larger MNDs. Initial treatment with Not Acclimated birds showed larger MNDs. Additionally, control growing quail demonstrated positive correlations with fiber size, whereas fast growing quail did not. This may mean that nuclei in larger fibers of fast-growing quail may be functioning maximally, and that increases in temperature may also demonstrate similar effects.
近年来，人们加紧努力，以确定可能使物种具有适应或易受全球温度变化影响的生理特征。温度对生物功能至关重要；因此，气候变化有可能严重影响许多物种生物组织的各个层次。例如，环境温度的升高可能会改变鸟类的肌肉结构和功能。肌核领域（MND）是鸟类肌肉生理学中一个研究不足的方面，它会因热应激而发生变化，其定义为每个核负责服务的肌纤维内的细胞质量。在这里，我们使用了两种代表对照和快速生长速度的随机繁殖的日本鹌鹑（Coturnix japonica）品系。我们使用析因设计向每条线施用四种处理组合-最初的热应激适应期（适应）或无适应（未适应），然后在 8 周龄后进行热应激挑战（HS）或无挑战（NC），以确定热适应和急性热应激对鹌鹑 MND 的影响。我们发现线*最终处理之间存在显着的相互作用，快速生长的 HS 鸟类的每个纤维核数最低，而适应的对照生长鸟类的每个纤维核数最高。MND 对线有显着影响，快速生长的线具有较大的 MND。未适应鸟类的初始处理显示出较大的 MND。此外，对照生长的鹌鹑与纤维大小呈正相关，而快速生长的鹌鹑则没有。这可能意味着快速生长的鹌鹑较大纤维中的核可能正在最大程度地发挥作用，并且温度升高也可能产生类似的效果。
