Photosynthate accumulation in solar-powered sea slugs - starving slugs survive due to accumulated starch reserves.
Photosynthate accumulation in solar-powered sea slugs - starving slugs survive due to accumulated starch reserves.
复制标题
太阳能海蛞蝓体内光合产物的积累——饥饿的海蛞蝓因积累的淀粉储备而得以生存。
DOI：
10.1186/s12983-016-0186-5
复制
发表时间：
2017
影响因子：
2.8
通讯作者：
Wägele H
中科院分区：
文献类型：
--
作者：
Laetz EMJ;Moris VC;Moritz L;Haubrich AN;Wägele H
太阳能海蛞蝓以其在饥饿中生存的能力而闻名，这是因为它们融入了藻类叶绿体。这是公认的，藻类衍生的碳可以追溯到许多蛞蝓衍生的化合物，表明蛞蝓利用光合作用所产生的质体。最近，一种新的假说认为，产生的光合作用并不是持续不断地提供给蛞蝓。相反，至少有一些质体的光合产物储存在质体本身中，只有在以后才能被蛞蝓利用。对长时间保留质体的海蛞蝓Elysia timida及其唯一食物源髋臼菌Acetabularia acetabulum进行了研究，以确定其是否产生淀粉，即直链淀粉和支链淀粉的组合以及主要的光合产物。髋臼，是由被盗的质体产生的，以及它是否在个体的盗质体中积累，提供能量储藏室，在稍后的时间为鼻涕虫提供能量。在整个饥饿期间，Elysia timida的组织切片用Lugol碘溶液染色，Lugol碘溶液是植物中淀粉颗粒的众所周知的染色剂。我们在这里提出的第一次，增加直链淀粉浓度，在蛞蝓的消化腺细胞在饥饿期间，随后急剧下降。化学阻断这些组织中的光合作用导致没有可观察到的淀粉，表明未处理动物中的淀粉是光合作用活性的产物。这表明，盗质体既可以作为营养生产者，也可以作为储存装置，在一定时间内保持它们产生的多糖，直到它们最终被饥饿的蛞蝓利用，以承受延长的饥饿期。
Solar-powered sea slugs are famed for their ability to survive starvation due to incorporated algal chloroplasts. It is well established that algal-derived carbon can be traced in numerous slug-derived compounds, showing that slugs utilize the photosynthates produced by incorporated plastids. Recently, a new hypothesis suggests that the photosynthates produced are not continuously made available to the slug. Instead, at least some of the plastid’s photosynthetic products are stored in the plastid itself and only later become available to the slug. The long-term plastid-retaining slug, Elysia timida and its sole food source, Acetabularia acetabulum were examined to determine whether or not starch, a combination of amylose and amylopectin and the main photosynthate produced by A. acetabulum, is produced by the stolen plastids and whether it accumulates within individual kleptoplasts, providing an energy larder, made available to the slug at a later time. Histological sections of Elysia timida throughout a starvation period were stained with Lugol’s Iodine solution, a well-known stain for starch granules in plants. We present here for the first time, an increase in amylose concentration, within the slug’s digestive gland cells during a starvation period, followed by a sharp decrease. Chemically blocking photosynthesis in these tissues resulted in no observable starch, indicating that the starch in untreated animals is a product of photosynthetic activity. This suggests that kleptoplasts function as both, a nutritive producer and storage device, holding onto the polysaccharides they produce for a certain time until they are finally available and used by the starving slug to withstand extended starvation periods.