The distribution of asterosaponins in various body components of the starfish Leptasterias polaris

Garneau, François-Xavier; Harvey, Cynthia; Simard, Jean-Guillaume; ApSimon, John W.; Burnell, D. Jean; Himmelman, John H.

doi:10.1016/0305-0491(89)90302-7

Cited by 12 publications

(6 citation statements)

References 15 publications

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“…Since ophiuroids in crevices are at greater risk of being preyed upon by the sea star, fleeing from crevices may reduce the probability of capture following encounter. It has been shown that many prey species of sea stars react to the presence of their predator through the detection of asterosaponins (molecules exuded by many sea star species) (Harvey et al 1987) and that these molecules are most concentrated in stomach tissues (Garneau et al 1989). The strong response to the stomach of A. vulgaris might be due to a higher concentration of asterosaponins.…”

Section: Discussionmentioning

confidence: 99%

Use of refuges by the ophiuroid Ophiopholis aculeata: contrasting effects of substratum complexity on predation risk from two predators

Drolet¹,

Himmelman

Rochette³

2004

Mar. Ecol. Prog. Ser.

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We investigated the effect of substratum complexity on the vulnerability of the ophiuroid Ophiopholis aculeata to its 2 main predators, the sea star Asterias vulgaris (possibly synonymous with A. rubens) and the urchin Strongylocentrotus droebachiensis, and further examined behavioral responses of ophiuroids to these predators. Field and laboratory experiments showed that the use of crevices by ophiuroids tended to reduce predation by urchins. The ophiuroids' response to contact with the urchin was to retract deeper into crevices. In contrast, in the laboratory, the ophiuroids' vulnerability to the sea star was higher on complex substrata. In the laboratory, ophiuroids reacted weakly to contact with the arm tip or ambulacral groove of A. vulgaris, but immediately fled refuges when there was contact with the sea star's stomach. In the field, the density of ophiuroids in 20 cm diameter circular plots placed around sea stars (both feeding and non-feeding) was similar to that in areas without sea stars. However, the estimated density of ophiuroids directly under sea stars was less than in areas without sea stars, and exposed ophiuroids (with the disk outside a crevice) were more abundant near A. vulgaris than in areas without sea stars: both differences were greater when the sea star was feeding. Ophiuroids display risk sensitivity adjusted to the 2 predators. They mainly flee crevices under a sea star when there is contact with the sea star's stomach, but only move a few centimeters. A last-moment departure should increase the probability of capture by sea stars, but reduces time spent on open surfaces where they are vulnerable to urchin attacks.

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Section: Discussionmentioning

confidence: 99%

Use of refuges by the ophiuroid Ophiopholis aculeata: contrasting effects of substratum complexity on predation risk from two predators

Drolet¹,

Himmelman

Rochette³

2004

Mar. Ecol. Prog. Ser.

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“…Considering both asteroids and holothuroids and based on observations of organ-specific saponin contents [14,50] and behavioral experiments [71], it has been suggested that saponins could contribute to digestion [70,72], reproduction (e.g., spawn synchronisation) [73,74], as well as intra or interspecific chemical signaling [17,71,75,76,77].…”

Section: Saponin Occurrence and Diversity In Echinodermsmentioning

confidence: 99%

Triterpenoids in Echinoderms: Fundamental Differences in Diversity and Biosynthetic Pathways

et al. 2019

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Echinoderms form a remarkable phylum of marine invertebrates that present specific chemical signatures unique in the animal kingdom. It is particularly the case for essential triterpenoids that evolved separately in each of the five echinoderm classes. Indeed, while most animals have Δ5-sterols, sea cucumbers (Holothuroidea) and sea stars (Asteroidea) also possess Δ7 and Δ9(11)-sterols, a characteristic not shared with brittle stars (Ophiuroidea), sea urchins (Echinoidea), and crinoids (Crinoidea). These particular Δ7 and Δ9(11) sterols emerged as a self-protection against membranolytic saponins that only sea cucumbers and sea stars produce as a defense mechanism. The diversity of saponins is large; several hundred molecules have been described in the two classes of these saponins (i.e., triterpenoid or steroid saponins). This review aims to highlight the diversity of triterpenoids in echinoderms by focusing on sterols and triterpenoid glycosides, but more importantly to provide an updated view of the biosynthesis of these molecules in echinoderms.

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“…Seasonal studies of star¢sh (Yasumoto et al, 1966;Mackie et al, 1977) described a close relation between saponin levels in the tissues and spawning activity in females. Moreover, the structure of saponins found in the star¢sh Leptasterias polaris by Garneau et al (1989) varied seasonally, suggesting a possible change in their role or e¡ect over the year.…”

Section: Discussionmentioning

confidence: 99%

Mucus as a mediator of gametogenic synchrony in the sea cucumber Cucumaria frondosa (Holothuroidea: Echinodermata)

Hamel¹,

Mercier²

1999

J. Mar. Biol. Ass.

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The data presented here demonstrate that the sea cucumber Cucumaria frondosa secretes a biologically active mucus that helps maintain gametogenic synchrony among conspecifics. Either a whole mature individual or a sample of its freshly collected mucus was able to initiate gametogenesis in conspecifics that were in the gametogenic recovery stage when other environmental conditions, including daylength, were maintained constant. Similar results were obtained when the mucus was kept in seawater for less than 3 h prior to its use, whereas after 6 h in seawater, the mucus had lost its inducing properties. Laboratory experiments showed that the mucus was produced in lesser amount during late summer and autumn; the production rapidly increased in early January to reach a peak a few months before the June spawning, in 1992 and 1993. The increment of mucus production was concurrent with the initiation of gametogenesis. Synthesis of mucus was maximal in individuals having attained gametogenic maturity and minimum in individuals with less developed gonads. At first relatively stable in seawater, the mucus gradually lost its integrity within a period of 3–5 h, suggesting that the mucus may be carried over long distances by currents, thus allowing a transfer of information before its complete degradation. This phenomenon was observed in the field where streams of mucus could be followed by SCUBA divers as far as 20–30 m away from the secreting animal. The data presented here are the first evidence of the important role played by mucus secretion during the gametogenic processes of an echinoderm.

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The distribution of asterosaponins in various body components of the starfish Leptasterias polaris

Cited by 12 publications

References 15 publications

Use of refuges by the ophiuroid Ophiopholis aculeata: contrasting effects of substratum complexity on predation risk from two predators

Use of refuges by the ophiuroid Ophiopholis aculeata: contrasting effects of substratum complexity on predation risk from two predators

Triterpenoids in Echinoderms: Fundamental Differences in Diversity and Biosynthetic Pathways

Mucus as a mediator of gametogenic synchrony in the sea cucumber Cucumaria frondosa (Holothuroidea: Echinodermata)

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