scholarly journals INTRASPECIFIC AGGRESSION AND ITS EFFECT ON THE DISTRIBUTION OF ANTHOPLEURA ELEGANTISSIMA AND SOME RELATED SEA ANEMONES

1973 ◽  
Vol 144 (1) ◽  
pp. 73-92 ◽  
Author(s):  
LISBETH FRANCIS
Keyword(s):  
Intraspecific Aggression ◽  
Sea Anemones ◽  
Anthopleura Elegantissima

Aspects of the larval biology of the sea anemones Anthopleura elegantissima and A. artemisia

2005 ◽  
Vol 121 (3) ◽  
pp. 190-201 ◽  
Author(s):  
Virginia M. Weis ◽  
E. Alan Verde ◽  
Alena Pribyl ◽  
Jodi A. Schwarz
Keyword(s):  
Sea Anemones ◽  
Larval Biology ◽  
Anthopleura Elegantissima

Some Recent Observations on the Acrorhagi of Sea Anemones

1978 ◽  
Vol 58 (3) ◽  
pp. 787-788 ◽  
Keyword(s):  
Aggressive Behaviour ◽  
The Body ◽  
Sea Anemones ◽  
Oral Disc ◽  
Anthopleura Elegantissima ◽  
Repeated Contact

Certain endomyarian sea anemones possess marginal spherules or acrorhagi (Stephenson, 1928) which are employed only in aggressive behaviour towards other Anthozoa. The acrorhagi can be dilated and movements of the oral disc and column bring them into contact with an adversary. Pieces of acrorhagial ectoderm adhere to the body of the adversary whilst discharging into it the large atrich nematocysts characteristic of acrorhagi. Such behaviour has been described in the European anemone Actinia equina (L.) and the Californian anemones Anthopleura elegantissima (Brandt) and Anthopleura artemisia (Dana) (Äbel, 1954; Bonnin, 1964; Francis, 1973). Aggression usually occurs only following repeated contact with a genotypically distinct anemone: mere proximity does not usually initiate any response (Francis, 1973).I have recently seen similar behaviour, apparently not recorded before, in the European anemone Anthopleura ballii (Cocks) collected from Weymouth, England. Specimens were kept in an aerated aquarium with other anemones and fed irregularly: the behaviour observed occurred between 19.00 and 22.00 h G.M.T. during August and November 1977. Following contact between two specimens of different colour varieties and the subsequent use of acrorhagi by one of them, the light-coloured passive individual immediately moved away from the dark-coloured aggressor and remained partly contracted with a ‘withered’ appearance to the tentacles for 1 week, following which it recovered (August). The same aggressor later (November) attacked a Cereus pedunculatus (Pennant), causing it to detach immediately from the substrate and to become necrotic one day later. The Cereus remained detached with the tentacles retracted and the column swollen for 5 days before it recovered.

scholarly journals DNA METHYLATION PROFILING OF A CNIDARIAN-ALGAL SYMBIOSIS USING NANOPORE SEQUENCING

2021 ◽  
Author(s):  
James L. Dimond ◽  
Nhung Nguyen ◽  
Steven B. Roberts
Keyword(s):  
Draft Genome ◽  
Genomic Region ◽  
Nanopore Sequencing ◽  
Sea Anemones ◽  
Cpg Dinucleotides ◽  
Algal Symbiosis ◽  
Anthopleura Elegantissima ◽  
Base Modifications ◽  
Pass Through ◽  
Methylation Profiling

ABSTRACTSymbiosis with protists is common among cnidarians such as corals and sea anemones, and is associated with homeostatic and phenotypic changes in the host that could have epigenetic underpinnings, such as methylation of CpG dinucleotides. We leveraged the sensitivity to base modifications of nanopore sequencing to probe the effect of symbiosis with the chlorophyte Elliptochloris marina on methylation in the sea anemone Anthopleura elegantissima. We first validated the approach by comparison of nanopore-derived methylation levels with CpG depletion analysis of a published transcriptome, finding that high methylation levels are associated with CpG depletion as expected. Next, using reads generated exclusively from aposymbiotic anemones, a largely complete draft genome comprising 243 Mb was assembled. Reads from aposymbiotic and symbiotic sea anemones were then mapped to this genome and assessed for methylation using the program Nanopolish, which detects signal disruptions from base modifications as they pass through the nanopore. Based on assessment of 452,841 CpGs for which there was adequate read coverage (approximately 8% of the CpGs in the genome), symbiosis with E. marina was, surprisingly, associated with only subtle changes in the host methylome. However, we did identify one extended genomic region with consistently higher methylation among symbiotic individuals. The region was associated with a DNA polymerase zeta that is noted for its role in translesion synthesis, which opens interesting questions about the biology of this symbiosis. Our study highlights the power and relative simplicity of nanopore sequencing for studies of nucleic acid base modifications in non-model species.

Further Analysis of Individual Spacing within Aggregations of the Anemone, Actinia Equina

1985 ◽  
Vol 65 (1) ◽  
pp. 35-53 ◽  
Author(s):  
R. C. Brace ◽  
D. L. J. Quicke
Keyword(s):  
Genetic Diversity ◽  
East Coast ◽  
Genotypic Diversity ◽  
Intraspecific Aggression ◽  
Aggressive Interactions ◽  
Anthopleura Elegantissima

We have recently assessed phenotypic and genotypic diversity within an aggregation of the intertidal beadlet anemone, Actinia equina L., located at Burniston in N. Yorkshire, on the east coast of Britain (Quicke & Brace, 1983). The study was undertaken in order to provide information relating to the role of intraspecific aggression (Bonnin, 1964; Brace & Pavey, 1978; Brace, Pavey & Quicke, 1979) in modifying the spacing of individuals. Limited work on the genus Actinia (A. tenebrosa Farquhar) has already indicated that whilst genetically dissimilar anemones display aggression towards one another, auto-genotypic aggression is minimal (Ayre, 1982), as is also the case for the clonal anemone, Anthopleura elegantissima (Brandt) (Francis, 1973a,b,1976). We therefore anticipated that aggressive interactions would promote auto-genotypic clustering, initiated by the local settlement of the asexually produced, brooded young (Carter & Thorp, 1979; Gashout & Ormond, 1979; Orr, Thorpe & Carter, 1982), and that correspondingly, genetic diversity within aggregations of anemones would be low.

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