Ultrastructural identification of glial cells in the oral area of the comb-bearer Berë cucumis

Aronova, M. Z.; Алексеева, Т. М.

doi:10.1007/s10893-005-0027-1

Cited by 2 publications

(2 citation statements)

References 4 publications

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“…Experiments with fluorescent tracers could clarify the genealogy of different classes of mesoglean cells in development. Hypothetical glia-like cells were also described in Beroe (Aronova and Alekseeva, 2004), but the very concept of 'glia' in these neural systems should be reevaluated to avoid implementation of the terminology developed for vertebrates.…”

Section: Enigmatic Ctenophore Neuronsmentioning

confidence: 99%

Convergent evolution of neural systems in ctenophores

Moroz

2015

Journal of Experimental Biology

120

139

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Neurons are defined as polarized secretory cells specializing in directional propagation of electrical signals leading to the release of extracellular messengers -features that enable them to transmit information, primarily chemical in nature, beyond their immediate neighbors without affecting all intervening cells en route. Multiple origins of neurons and synapses from different classes of ancestral secretory cells might have occurred more than once during ~600 million years of animal evolution with independent events of nervous system centralization from a common bilaterian/cnidarian ancestor without the bona fide central nervous system. Ctenophores, or comb jellies, represent an example of extensive parallel evolution in neural systems. First, recent genome analyses place ctenophores as a sister group to other animals. Second, ctenophores have a smaller complement of pan-animal genes controlling canonical neurogenic, synaptic, muscle and immune systems, and developmental pathways than most other metazoans. However, comb jellies are carnivorous marine animals with a complex neuromuscular organization and sophisticated patterns of behavior. To sustain these functions, they have evolved a number of unique molecular innovations supporting the hypothesis of massive homoplasies in the organization of integrative and locomotory systems. Third, many bilaterian/cnidarian neuron-specific genes and 'classical' neurotransmitter pathways are either absent or, if present, not expressed in ctenophore neurons (e.g. the bilaterian/cnidarian neurotransmitter, γ-amino butyric acid or GABA, is localized in muscles and presumed bilaterian neuronspecific RNA-binding protein Elav is found in non-neuronal cells). Finally, metabolomic and pharmacological data failed to detect either the presence or any physiological action of serotonin, dopamine, noradrenaline, adrenaline, octopamine, acetylcholine or histamineconsistent with the hypothesis that ctenophore neural systems evolved independently from those in other animals. Glutamate and a diverse range of secretory peptides are first candidates for ctenophore neurotransmitters. Nevertheless, it is expected that other classes of signal and neurogenic molecules would be discovered in ctenophores as the next step to decipher one of the most distinct types of neural organization in the animal kingdom.

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Section: Enigmatic Ctenophore Neuronsmentioning

confidence: 99%

Convergent evolution of neural systems in ctenophores

Moroz

2015

Journal of Experimental Biology

120

139

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“…Ctenophora mesoglea contains amoeboid cells called stellate cells that phagocytose cell debris and bacteria 97 , 98 . A role for stellate cells in wound healing has been demonstrated in Mnemiopsis leidyi 98 , 99 .…”

Section: Discussionmentioning

confidence: 99%

Placozoan fiber cells: mediators of innate immunity and participants in wound healing

Mayorova

Hammar

Jung

et al. 2021

Sci Rep

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Placozoa is a phylum of non-bilaterian marine animals. These small, flat organisms adhere to the substrate via their densely ciliated ventral epithelium, which mediates mucociliary locomotion and nutrient uptake. They have only six morphological cell types, including one, fiber cells, for which functional data is lacking. Fiber cells are non-epithelial cells with multiple processes. We used electron and light microscopic approaches to unravel the roles of fiber cells in Trichoplax adhaerens, a representative member of the phylum. Three-dimensional reconstructions of serial sections of Trichoplax showed that each fiber cell is in contact with several other cells. Examination of fiber cells in thin sections and observations of live dissociated fiber cells demonstrated that they phagocytose cell debris and bacteria. In situ hybridization confirmed that fiber cells express genes involved in phagocytic activity. Fiber cells also are involved in wound healing as evidenced from microsurgery experiments. Based on these observations we conclude that fiber cells are multi-purpose macrophage-like cells. Macrophage-like cells have been described in Porifera, Ctenophora, and Cnidaria and are widespread among Bilateria, but our study is the first to show that Placozoa possesses this cell type. The phylogenetic distribution of macrophage-like cells suggests that they appeared early in metazoan evolution.

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Ultrastructural identification of glial cells in the oral area of the comb-bearer Berë cucumis

Cited by 2 publications

References 4 publications

Convergent evolution of neural systems in ctenophores

Convergent evolution of neural systems in ctenophores

Placozoan fiber cells: mediators of innate immunity and participants in wound healing

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