The formation of extracellular DNA traps (ETosis) is a first response mechanism by specific immune cells following exposure to microbes. Initially characterized in vertebrate neutrophils, cells capable of ETosis have been discovered recently in diverse non-vertebrate taxa. To assess the conservation of ETosis between evolutionarily distant non-vertebrate phyla, we observed and quantified ETosis using the model ctenophore
- Award ID(s):
- 1831860
- NSF-PAR ID:
- 10123162
- Date Published:
- Journal Name:
- Integrative and Comparative Biology
- Volume:
- 59
- Issue:
- 4
- ISSN:
- 1540-7063
- Page Range / eLocation ID:
- 811 to 818
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Mnemiopsis leidyi and the oysterCrassostrea gigas . Here we report that ctenophores – thought to have diverged very early from the metazoan stem lineage – possess immune-like cells capable of phagocytosis and ETosis. We demonstrate that bothMnemiopsis andCrassostrea immune cells undergo ETosis after exposure to diverse microbes and chemical agents that stimulate ion flux. We thus propose that ETosis is an evolutionarily conserved metazoan defense against pathogens. -
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Abstract Ctenophores are descendants of an early branching basal metazoan lineage, which may have evolved neurons and muscles independently from other animals.
Mnemiopsis is one of the important reference ctenophore species. However, little is known about its neuromuscular organization. Here, we mapped and tracked the development of the neural and muscular elements in the early hatching cydippid larvae, as well as adultMnemiopsis leidyi Mnemiopsis was very similar toPleurobrachia bachei , although inMnemiopsis the entire process occurred significantly faster. The subepithelial neural cells were observed immediately after hatching. This population consisted of a dozen of separated individual neurons with short neurites. In about 2 days, when their neurites grew significantly longer and connected to their neighbors, they began to form a canonical polygonal subepithelial network. Mesogleal neural elements prominent in all studied adult ctenophores were not detectable inMnemiopsis larvae but were clearly labeled in closely related Lobata speciesBolinopsis infundibulum . Hatched larvae also had putative mechanoreceptors with long stereocilia and approximately two dozen muscle cells. In adultMnemiopsis, the feeding lobes and auricles contained two distinct populations of neurons and neural ensembles that were not observed in other ctenophore lineages and likely represented elaborate neuronal innovations characteristic for the clade Lobata and their lifestyles. -
Ctenophores (a.k.a. comb jellies) are one of the earliest branching extant metazoan phyla. Adult regenerative ability varies greatly within the group, with platyctenes undergoing both sexual and asexual reproduction by fission while others in the genus Beroe having completely lost the ability to replace missing body parts. We focus on the unique regenerative aspects of the lobate ctenophore, Mnemiopsis leidyi, which has become a popular model for its rapid wound healing and tissue replacement, optical clarity, and sequenced genome. M. leidyi’s highly mosaic, stereotyped development has been leveraged to reveal the polar coordinate system that directs whole-body regeneration as well as lineage restriction of replacement cells in various regenerating organs. Several cell signaling pathways known to function in regeneration in other animals are absent from the ctenophore’s genome. Further research will either reveal ancient principles of the regenerative process common to all animals or reveal novel solutions to the stability of cell fates and whole-body regeneration.more » « less
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Abstract Ctenophora is an early‐branching basal metazoan lineage, which may have evolved neurons and muscles independently from other animals. However, despite the profound diversity among ctenophores, basal neuroanatomical data are limited to representatives of two genera. Here, we describe the organization of neuromuscular systems in eight ctenophore species focusing on
Euplokamis dunlapae —the representative of the lineage sister to all other ctenophores. Cydippids (Hormiphora hormiphora andDryodora glandiformis ) and lobates (Bolinopsis infundibulum andMnemiopsis leidyi ) were used as reference platforms to cover both morphological and ecological diversity within the phylum. We show that even with substantial environmental differences, the basal organization of neural systems is conserved among ctenophores. In all species, we detected two distributed neuronal subsystems: the subepithelial polygonal network and the mesogleal elements. Nevertheless, each species developed specific innovations in neural, muscular, and receptor systems. Most notableEuplokamis ‐specific features are the following: (a) Comb nerves with giant axons. These nerves directly coordinate the rapid escape response bypassing the central integrative structure known as the aboral sensory organ. (b) Neural processes in tentacles along the rows of “boxes” providing structural support and located under striated muscles. (c) Radial muscles that cross the mesoglea and connect the outer wall to the aboral canal. (d) Flat muscles, encircling each meridional canal. Also, we detected a structurally different rectangular neural network in the feeding lobes of Lobata (Mnemiopsis/Bolinopsis ) but not in other species. The described lineage‐specific innovations can be used for future single‐cell atlases of ctenophores and analyses of neuronal evolution in basal metazoans. -
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1093/icb/icz116
