High concentrations of trimethylamines in slime glands inhibit skein unraveling in Pacific hagfish
High concentrations of trimethylamines in slime glands inhibit skein unraveling in Pacific hagfish
复制标题
粘液腺中高浓度的三甲胺抑制太平洋盲鳗的绞纱散开
DOI：
10.1242/jeb.213793
复制
发表时间：
2019
影响因子：
2.8
通讯作者：
D. Fudge
中科院分区：
文献类型：
--
作者：
Gaurav Jain;Marie Starksen;Kashika Singh;Christopher Hoang;P. Yancey;C. McCord;D. Fudge
摘要盲鳗在受到鱼类捕食者的攻击时，会分泌大量的粘液来保护自己。粘液由海水和粘液腺喷出的两种主要成分组成：粘液和丝线。这些线是在专门的细胞中产生的，并被包装成错综复杂的盘绕束，称为绞纱。当绞肉从粘液腺中排出时，蛋白质粘合剂会溶解，从而防止绞肉散开。先前的工作表明，盲鳗粘液腺具有高浓度的甲胺，包括三甲胺N-氧化物（TMAO），三甲基甘氨酸（甜菜碱）和二甲基甘氨酸（DMG）;然而，这些化合物在粘液腺中的功能尚不清楚。我们假设，甲胺有稳定的效果，防止过早解开在腺体的绞。为了验证这一假设，我们量化了甲胺对太平洋盲鳗绞纱解开的影响，并发现TMAO和甜菜碱在体外对绞纱解开有抑制作用。此外，我们发现TMAO是比甜菜碱更有效的解开抑制剂，但TMAO的存在协同增强甜菜碱的抑制作用。甘氨酸和DMG在自然浓度下对解链的抑制作用要小得多。我们的研究结果支持这一假设，高水平的三甲基胺的粘液腺可能会采取行动，以保持卷曲的线程绞在一起的腺线程细胞内，他们可能会这样做，通过稳定的粘附蛋白。这些结果推进了我们对绞纱稳定和部署的认识，并提供了三甲基胺在海洋生物中稳定蛋白质的另一个例子。突出显示的文章：太平洋八目鳗粘液腺中的高水平的三甲基胺通过稳定粘附蛋白来稳定绞肉并防止其解开。
ABSTRACT Hagfish defend themselves from fish predators by producing large volumes of gill-clogging slime when they are attacked. The slime consists of seawater and two major components that are ejected from the slime glands: mucus and threads. The threads are produced within specialized cells and packaged into intricately coiled bundles called skeins. Skeins are kept from unraveling via a protein adhesive that dissolves when the skeins are ejected from the slime glands. Previous work revealed that hagfish slime glands have high concentrations of methylamines including trimethylamine N-oxide (TMAO), trimethylglycine (betaine) and dimethylglycine (DMG); however, the function of these compounds in the slime glands is unknown. We hypothesized that methylamines have stabilizing effects on the skeins that prevent premature unraveling in the gland. To test this hypothesis, we quantified the effect of methylamines on skein unraveling in Pacific hagfish and found that TMAO and betaine have inhibitory effects on skein unraveling in vitro. Furthermore, we found that TMAO is a more effective inhibitor of unraveling than betaine, but the presence of TMAO synergistically boosts the inhibitory action of betaine. Glycine and DMG were far less effective inhibitors of unraveling at natural concentrations. Our results support the hypothesis that high levels of trimethylamines in the slime glands may act to hold the coiled thread skeins together within gland thread cells, and they may do so by stabilizing adhesive proteins. These results advance our knowledge of skein stabilization and deployment and provide yet another example of trimethylamines functioning to stabilize proteins in a marine organism. Highlighted Article: High levels of trimethylamines in slime glands of the Pacific hagfish stabilize the skeins and prevent their unraveling by stabilizing adhesive proteins.