The Hadal Amphipod Hirondellea gigas possessing a unique cellulase for digesting wooden debris buried in the deepest seafloor.
The Hadal Amphipod Hirondellea gigas possessing a unique cellulase for digesting wooden debris buried in the deepest seafloor.
复制标题
DOI：
10.1371/journal.pone.0042727
复制
发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
Takami H
中科院分区：
文献类型：
--
作者：
Kobayashi H;Hatada Y;Tsubouchi T;Nagahama T;Takami H
马里亚纳海沟的挑战者深度是海洋中最深的点（10,994米）。某些深海动物能够承受如此深的海底的巨大压力。片脚类动物Hirondellea gigas是挑战者深渊的居民。片脚类动物是深海中常见的居民，也是食腐动物。然而，关于H. gigas的生理学或这种生物在半深海区的生态相互作用的信息相对较少。为了了解这种清道夫在最深处低营养深渊的摄食行为，我们分析了全身提取物中的消化酶。我们描述了淀粉酶、纤维素酶、甘露聚糖酶、木聚糖酶和α-糖苷酶活性的检测，这些酶能够消化植物来源的多糖。我们在H. gigas提取物中发现了葡萄糖、麦芽糖和纤维素二糖，这表明这些酶在巨大的原位压力下起作用。实际上，H. gigas的葡萄糖含量平均为0.4% （w/dry w）。纯化的H. gigas纤维素酶（HGcel）以2∶1的摩尔比将纤维素转化为葡萄糖和纤维素二糖，并在35℃下有效地从干燥的木材（一种天然纤维素生物质）中生产葡萄糖。在2°C的高静水压力为100 MPa的条件下，酶活性增加，相当于在挑战者深处发现的条件。对HGcel的氨基酸序列分析支持其属于31家族糖基水解酶。然而，这个家族的酶以前都没有被证明具有纤维素酶活性。这些结果强烈表明，H. gigas通过进化出能够消化沉没木屑的消化酶来适应其极端寡营养hadal海洋环境。
The Challenger Deep in the Mariana Trench is the deepest point in the ocean (10,994 m). Certain deep-sea animals can withstand the extreme pressure at this great depth. The amphipod Hirondellea gigas is a resident of the Challenger Deep. Amphipods are common inhabitants at great depths and serve as scavengers. However, there is relatively little information available regarding the physiology of H. gigas or this organism's ecological interactions in the hadopelagic zone. To understand the feeding behavior of this scavenger in the deepest oligotrophic hadal zone, we analyzed the digestive enzymes in whole-body extracts. We describe the detection of amylase, cellulase, mannanase, xylanase, and α-glycosidase activities that are capable of digesting plant-derived polysaccharides. Our identification of glucose, maltose, and cellobiose in the H. gigas extracts indicated that these enzymes function under great pressure in situ. In fact, the glucose content of H. gigas averaged 0.4% (w/dry-w). The purified H. gigas cellulase (HGcel) converted cellulose to glucose and cellobiose at an exceptional molar ratio of 2∶1 and efficiently produced glucose from dried wood, a natural cellulosic biomass, at 35°C. The enzyme activity increased under a high hydrostatic pressure of 100 MPa at 2°C, conditions equivalent to those found in the Challenger Deep. An analysis of the amino acid sequence of HGcel supported its classification as a family 31 glycosyl hydrolase. However, none of the enzymes of this family had previously been shown to possess cellulase activity. These results strongly suggested that H. gigas adapted to its extreme oligotrophic hadal oceanic environment by evolving digestive enzymes capable of digesting sunken wooden debris.
登录
查看更多内容
影响因子：
64.8
作者：
Clark, Andrew G.;Eisen, Michael B.;MacCallum, Iain
通讯作者：
MacCallum, Iain
影响因子：
1.2
作者：
Leal, JH;Harasewych, MG
通讯作者：
Harasewych, MG
影响因子：
1.7
作者：
Nyssen, F;Brey, T;Dauby, P
通讯作者：
Dauby, P
影响因子：
10.7
作者：
Davison, A;Blaxter, M
通讯作者：
Blaxter, M
影响因子：
2.5
作者：
FRANCE, SC
通讯作者：
FRANCE, SC