A study of the temporary adhesion of the podia in the sea star asterias rubens (Echinodermata, asteroidea) through their footprints

1998 ◽  
Vol 201 (16) ◽  
pp. 2383-2395 ◽  
Author(s):  
P Flammang ◽  
A Michel ◽  
AV Cauwenberge ◽  
H Alexandre ◽  
M Jangoux

Sea stars are able to make firm but temporary attachments to various substrata owing to secretions released by their podia. A duo-glandular model has been proposed in which an adhesive material is released by two types of non-ciliated secretory (NCS1 and NCS2) cells and a de-adhesive material is released by ciliated secretory (CS) cells. The chemical composition of these materials and the way in which they function have been investigated by studying the adhesive footprints left by the asteroids each time they adhere to a substratum. The footprints of Asterias rubens consist of a sponge-like material deposited as a thin layer on the substratum. Inorganic residues apart, this material is made up mainly of proteins and carbohydrates. The protein moiety contains significant amounts of both charged (especially acidic) and uncharged polar residues as well as half-cystine. The carbohydrate moiety is also acidic, comprising both uronic acids and sulphate groups. Polyclonal antibodies have been raised against footprint material and were used to locate the origin of footprint constituents in the podia. Extensive immunoreactivity was detected in the secretory granules of both NCS1 and NCS2 cells, suggesting that their secretions together make up the bulk of the adhesive material. No immunoreactivity was detected in the secretory granules of CS cells, and the only other structure strongly labelled was the outermost layer of the cuticle, the fuzzy coat. This pattern of immunoreactivity suggests that the secretions of CS cells are not incorporated into the footprints, but instead might function to jettison the fuzzy coat, thereby allowing the podium to detach.

2008 ◽  
Vol 164 (1) ◽  
pp. 108-118 ◽  
Author(s):  
Elise Hennebert ◽  
Pascal Viville ◽  
Roberto Lazzaroni ◽  
Patrick Flammang

2018 ◽  
Vol 9 ◽  
pp. 2071-2086 ◽  
Author(s):  
Birgit Lengerer ◽  
Marie Bonneel ◽  
Mathilde Lefevre ◽  
Elise Hennebert ◽  
Philippe Leclère ◽  
...  

Background: Marine biological adhesives are a promising source of inspiration for biomedical and industrial applications. Nevertheless, natural adhesives and especially temporary adhesion systems are mostly unexplored. Sea stars are able to repeatedly attach and detach their hydraulic tube feet. This ability is based on a duo-gland system and, upon detachment, the adhesive material stays behind on the substrate as a 'footprint'. In recent years, characterization of sea star temporary adhesion has been focussed on the forcipulatid species Asterias rubens. Results: We investigated the temporary adhesion system in the distantly related valvatid species Asterina gibbosa. The morphology of tube feet was described using histological sections, transmission-, and scanning electron microscopy. Ultrastructural investigations revealed two adhesive gland cell types that both form electron-dense secretory granules with a more lucid outer rim and one de-adhesive gland cell type with homogenous granules. The footprints comprised a meshwork on top of a thin layer. This topography was consistently observed using various methods like scanning electron microscopy, 3D confocal interference microscopy, atomic force microscopy, and light microscopy with crystal violet staining. Additionally, we tested 24 commercially available lectins and two antibodies for their ability to label the adhesive epidermis and footprints. Out of 15 lectins labelling structures in the area of the duo-gland adhesive system, only one also labelled footprints indicating the presence of glycoconjugates with α-linked mannose in the secreted material. Conclusion: Despite the distant relationship between the two sea star species, the morphology of tube feet and topography of footprints in A. gibbosa shared many features with the previously described findings in A. rubens. These similarities might be due to the adaptation to a benthic life on rocky intertidal areas. Lectin- and immuno-labelling indicated similarities but also some differences in adhesive composition between the two species. Further research on the temporary adhesive of A. gibbosa will allow the identification of conserved motifs in sea star adhesion and might facilitate the development of biomimetic, reversible glues.


2021 ◽  
Author(s):  
Hugh F. Carter ◽  
Jeffrey R. Thompson ◽  
Maurice R. Elphick ◽  
Paola Oliveri

AbstractFree-swimming planktonic larvae are a key stage in the development of many marine phyla, and studies of these organisms have contributed to our understanding of major genetic and evolutionary processes. Although transitory, these larvae often attain a remarkable degree of tissue complexity, with well-defined musculature and nervous systems. Amongst the best studied are larvae belonging to the phylum Echinodermata, but with work largely focused on the pleuteus larvae of sea urchins (class Echinoidea). The greatest diversity of larval strategies amongst echinoderms is found in the class Asteroidea (sea-stars), organisms that are rapidly emerging as experimental systems for genetic and developmental studies. However, the bipinnaria larvae of sea stars have only been studied in detail in a small number of species and the full complexity of the nervous system is, in particular, poorly understood. Here we have analysed embryonic development and bipinnaria larval anatomy in the common North Atlantic sea-star Asterias rubens, employing use of a variety of staining methods in combination with confocal microscopy. Importantly, the complexity of the nervous system of bipinnaria larvae was revealed in greater detail than ever before, with identification of at least three centres of neuronal complexity: the anterior apical organ, oral region and ciliary bands. Furthermore, the anatomy of the musculature and sites of cell division in bipinnaria larvae were analysed. Comparisons of developmental progression and molecular anatomy across the Echinodermata provided a basis for hypotheses on the shared evolutionary and developmental processes that have shaped this group of animals. We conclude that bipinnaria larvae appear to be remarkably conserved across ~200 million years of evolutionary time and may represent a strong evolutionary and/or developmental constraint for species utilizing this larval strategy.


2019 ◽  
Vol 374 (1784) ◽  
pp. 20190195 ◽  
Author(s):  
Birgit Lengerer ◽  
Morgane Algrain ◽  
Mathilde Lefevre ◽  
Jérôme Delroisse ◽  
Elise Hennebert ◽  
...  

Sea stars use adhesive secretions to attach their numerous tube feet strongly and temporarily to diverse surfaces. After detachment of the tube feet, the adhesive material stays bound to the substrate as so-called ‘footprints’. In the common sea star species Asterias rubens , the adhesive material has been studied extensively and the first sea star footprint protein (Sfp1) has been characterized. We identified Sfp1-like sequences in 17 additional sea star species, representing different taxa and tube foot morphologies, and analysed the evolutionary conservation of this protein. In A. rubens , we confirmed the expression of 34 footprint proteins in the tube foot adhesive epidermis, with 22 being exclusively expressed in secretory cells of the adhesive epidermis and 12 showing an additional expression in the stem epidermis. The sequences were used for BLAST searches in seven asteroid transcriptomes providing a first insight in the conservation of footprint proteins among sea stars. Our results highlighted a high conservation of the large proteins making up the structural core of the footprints, whereas smaller, potential surface-binding proteins might be more variable among sea star species. This article is part of the theme issue ‘Transdisciplinary approaches to the study of adhesion and adhesives in biological systems’.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mark Hermes ◽  
Mitul Luhar

AbstractIntertidal sea stars often function in environments with extreme hydrodynamic loads that can compromise their ability to remain attached to surfaces. While behavioral responses such as burrowing into sand or sheltering in rock crevices can help minimize hydrodynamic loads, previous work shows that sea stars also alter body shape in response to flow conditions. This morphological plasticity suggests that sea star body shape may play an important hydrodynamic role. In this study, we measured the fluid forces acting on surface-mounted sea star and spherical dome models in water channel tests. All sea star models created downforce, i.e., the fluid pushed the body towards the surface. In contrast, the spherical dome generated lift. We also used Particle Image Velocimetry (PIV) to measure the midplane flow field around the models. Control volume analyses based on the PIV data show that downforce arises because the sea star bodies serve as ramps that divert fluid away from the surface. These observations are further rationalized using force predictions and flow visualizations from numerical simulations. The discovery of downforce generation could explain why sea stars are shaped as they are: the pentaradial geometry aids attachment to surfaces in the presence of high hydrodynamic loads.


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