Comparative ultrastructure of catch tentacles and feeding tentacles in the sea anemone Haliplanella

Watson, Glen M.; Mariscal, Richard N.

doi:10.1016/0040-8166(83)90059-9

Cited by 32 publications

(25 citation statements)

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“…As shown in figure 2d and electronic supplementary material, figure S3, the cells containing the Nv1 toxin indeed differ substantially from nematocytes in shape, and they lack nematocysts. Granule-rich gland cells that highly resemble the immunostained cells are common in the Nematostella tentacle ectoderm ( [28]; electronic supplementary material, figure S2) and were also described in tentacles of other sea anemone species [29][30][31]. Although accessibility of nematocysts for antibody staining is highly increased upon maceration with acetic acid that leads to their discharge, not a single nematocyst stained with anti-Nv1 was observed in the macerated Nematostella tissues.…”

Section: Resultsmentioning

confidence: 99%

Neurotoxin localization to ectodermal gland cells uncovers an alternative mechanism of venom delivery in sea anemones

et al. 2011

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Jellyfish, hydras, corals and sea anemones (phylum Cnidaria) are known for their venomous stinging cells, nematocytes, used for prey and defence. Here we show, however, that the potent Type I neurotoxin of the sea anemone Nematostella vectensis, Nv1, is confined to ectodermal gland cells rather than nematocytes. We demonstrate massive Nv1 secretion upon encounter with a crustacean prey. Concomitant discharge of nematocysts probably pierces the prey, expediting toxin penetration. Toxin efficiency in sea water is further demonstrated by the rapid paralysis of fish or crustacean larvae upon application of recombinant Nv1 into their medium. Analysis of other anemone species reveals that in Anthopleura elegantissima, Type I neurotoxins also appear in gland cells, whereas in the common species Anemonia viridis, Type I toxins are localized to both nematocytes and ectodermal gland cells. The nematocyte-based and gland cell-based envenomation mechanisms may reflect substantial differences in the ecology and feeding habits of sea anemone species. Overall, the immunolocalization of neurotoxins to gland cells changes the common view in the literature that sea anemone neurotoxins are produced and delivered only by stinging nematocytes, and raises the possibility that this toxin-secretion mechanism is an ancestral evolutionary state of the venom delivery machinery in sea anemones.

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Section: Resultsmentioning

confidence: 99%

Neurotoxin localization to ectodermal gland cells uncovers an alternative mechanism of venom delivery in sea anemones

et al. 2011

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“…Absence of visibly differentiated fighting tentacles in most specimens of D. manezinha and all specimens of D. leucolena is not exceptional within Diadumenidae, as these structures have never been observed in some species (e.g., D. fransciscana and D. lighti) and when present may appear in frequencies as low as 1.7% in some populations (e.g., populations of D. lineata in England: Williams, 1975). Likewise, fighting tentacles are ephemeral during an individual's lifespan, being induced by territorial threats from non-clonemates (Williams, 1975;Purcell, 1977;Watson and Mariscal, 1983a;Östman et al, 2010a) and restricted to individuals along the border of an aggregation facing other aggregates (Purcell, 1977;Purcell and Kitting, 1982). The reversal from fighting tentacles is also possible, being correlated with isolation of individuals to areas with non-clonemates or an animal's nutritional state (Williams, 1975;.…”

Section: Discussionmentioning

confidence: 99%

“…The reversal from fighting tentacles is also possible, being correlated with isolation of individuals to areas with non-clonemates or an animal's nutritional state (Williams, 1975;. In both instances, a change in nematocyst content accompanies the transformation (Purcell, 1977;Watson and Mariscal, 1983a).…”

Section: Discussionmentioning

confidence: 99%

“…In addition to having holotrichs, tentacles exhibited cnidae typical of feeding tentacles (i.e., spirocysts, basitrichs, and p-mastigophores B2a; fig. 5E-G, respectively), which is usually rare in fighting tentacles (Stephenson, 1935;Williams, 1975;Purcell, 1977;Watson and Mariscal, 1983a). This might suggest that feeding tentacles seen in specimens of D. leucolena were either in the early stages of transforming into fighting tentacles, given the predominance of small holotrichs over larger ones characteristic of later stages (table 1), or were in the process of reverting from fighting tentacles to feeding tentacles (see Watson and Mariscal, 1983b).…”

Section: Discussionmentioning

confidence: 99%

“…Likewise, Larson and Daly (2015) hypothesized that a non-differentiated tentacle with holotrichs and rare spirocysts in one specimen of the actineoidean Epiactis ritteri Torrey, 1902, is a fighting tentacle. Alternatively, it is possible that contamination of other parts of the tentacle with cnidae typical of feeding tentacles occurred during sampling of the tip of tentacles in which holotrichs are concentrated in fighting tentacles (Watson and Mariscal, 1983a).…”

Section: Discussionmentioning

confidence: 99%

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Sea Anemones through X-Rays: Visualization of Two Species ofDiadumene(Cnidaria, Actiniaria) Using Micro-CT

Gusmão

Grajales

Rodríguez

2018

American Museum Novitates

815

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Diadumenidae is a monogeneric family comprised of 10 valid species in the genus Diadumene. Although these species are distributed in all but the Southern Ocean, Diadumene lineata is a cosmopolitan species and one of the most widely distributed marine organisms. Recent phylogenetic analyses with multiple species have recovered Diadumenidae as a monophyletic group with high support. Although generic placement is straightforward, species-level identifications within Diadumene are difficult because species are defined by a mosaic of characters that vary in degree rather than kind. Two species of the genus have been recorded in the southwestern Atlantic: D. paranaensis along the south coast of Brazil and D. lineata along the southeast and northeast coasts of Brazil as well as in Argentina. Here we record D. leucolena for the first time in the southern hemisphere and describe D. manezinha, sp. nov., raising to four the number of species of Diadumene for Brazil and to 11 worldwide. We incorporated microcomputed tomography (micro-CT) into the description of both species in the first application of the method for Actiniaria. We evaluate the utility of micro-CT imaging and its potential to generate fast, low-cost, and high-resolution datasets despite the anemone's low-density soft tissue. We present a protocol for sample handling, chemical staining, and scanning parameters that resulted in satisfactory imaging of the two specimens examined. We also analyze advantages and limitations of using micro-CT over traditional techniques in the study of sea anemones.

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The Immunocytes of Protostomes and Deuterostomes as Revealed by LM, EM and Other Methods

Sawada

Tomonaga

1996

Advances in Comparative and Environmental Physiology

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Comparative ultrastructure of catch tentacles and feeding tentacles in the sea anemone Haliplanella

Cited by 32 publications

References 20 publications

Neurotoxin localization to ectodermal gland cells uncovers an alternative mechanism of venom delivery in sea anemones

Neurotoxin localization to ectodermal gland cells uncovers an alternative mechanism of venom delivery in sea anemones

Sea Anemones through X-Rays: Visualization of Two Species ofDiadumene(Cnidaria, Actiniaria) Using Micro-CT

The Immunocytes of Protostomes and Deuterostomes as Revealed by LM, EM and Other Methods

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