University of Silesia in Katowice, Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, Katowice, Poland.
J Morphol. 2021 Jan;282(1):48-65. doi: 10.1002/jmor.21281. Epub 2020 Oct 19.
Neocaridina davidi is a freshwater shrimp that originates from Taiwan and is commonly bred all over the word. Like all decapods, which develop indirectly, this species has pelagic larvae that may differ entirely in their morphology and habits from adult specimens. To fill a gap of knowledge about the developmental biology of freshwater shrimps we decided to document the 3D-localization of the midgut inside the body cavity of larval stages of N. davidi using X-ray microtomography, and to describe all structural and ultrastructural changes of the midgut epithelium (intestine and hepatopancreas) which occur during postembryonic development of N. davidi using light and transmission electron microscopy. We laid emphasis on stem cell functioning and cell death processes connected with differentiation. Our study revealed that while the intestine in both larval stages of N. davidi has the form of a fully developed organ, which resembles that of adult specimens, the hepatopancreas undergoes elongation and differentiation. E-cells, which are midgut stem cells, due to their proliferation and differentiation are responsible for the above-mentioned processes. Our study revealed that apoptosis is a common process in both larval stages of N. davidi in the intestine and proximal region of the hepatopancreas. In zoea III, autophagy as a survival factor is activated in order to protect cells against their death. However, when there are too many autophagic structures in epithelial cells, necrosis as passive cell death is activated. The presence of all types of cell death in the midgut in the zoea III stage confirms that this part of the digestive tract is fully developed and functional. Here, we present the first description of apoptosis, autophagy and necrosis in the digestive system of larval stages of Malacostraca and present the first description of their hepatopancreas elongation and differentiation due to midgut stem cell functioning.
大隅牛鼻鲼是一种源自台湾的淡水虾，广泛分布于世界各地。与所有间接发育的十足目动物一样，该物种具有完全不同形态和习性的浮游幼虫。为了填补淡水虾发育生物学知识的空白，我们决定使用 X 射线微断层扫描技术记录 N. davidi 幼虫期的中肠在体腔内的 3D 定位，并使用光镜和透射电镜描述中肠上皮（肠和肝胰腺）在 N. davidi 胚胎后发育过程中的所有结构和超微结构变化。我们特别强调与分化相关的干细胞功能和细胞死亡过程。我们的研究表明，虽然 N. davidi 的两个幼虫期的肠都具有完全发育的器官形态，类似于成体标本，但肝胰腺经历伸长和分化。E 细胞是中肠干细胞，由于其增殖和分化，负责上述过程。我们的研究表明，凋亡是 N. davidi 幼虫期肠和肝胰腺近端的常见过程。在幼体 III 期，自噬作为一种生存因子被激活，以保护细胞免受死亡。然而，当上皮细胞中存在过多的自噬结构时，坏死作为被动细胞死亡被激活。幼体 III 期中肠所有类型的细胞死亡的存在证实了这部分消化道已经完全发育并具有功能。在这里，我们首次描述了十足目幼虫期消化系统中的凋亡、自噬和坏死，并首次描述了它们的肝胰腺伸长和分化是由于中肠干细胞的功能。
