Starfish Marthasterias Glacialis Research Articles

Starfish acrosomal acid phosphatase: a cytochemical and biochemical study

The acrosome reaction of spermatozoa from the starfish Marthasterias glacialis was induced with the ionophore A23187. Reacted cells were then processed for acid phosphatase ultrastructural cytochemistry, but significant enzyme activity was not detected. However, when the supernates from suspensions of ionophore-treated sperm were assayed for acid phosphatase, a net enzyme activity was observed. Supernatant proteins were run in starch gel electrophoresis and fluorescent zymograms revealed a single band of acid phosphatase. SDS-PAGE of proteins eluted from the active spots of starch gels showed one major band of about 63 kDa. The results obtained support the hypothesis that the acid phosphatase whose activity has been detected only at the time of binding of sperm and egg originates from the sperm acrosome.

Silver staining of the cortical reaction in oocytes of Marthasterias glacialis (Echinodermata, Asteroidea)

Morphologically, cortical granules of the starfish Marthasterias glacialis present a lamellar structure within a dense matrix. However, with silver nitrate staining, the matrix is subdivided into argyrophilic and argyrophobic materials. Just before exocytosis the cortical granules swell. After being released in the perivitelline space, the unstained matrix disperses while the other components are incorporated into the vitelline layer. When cells are incubated with pronase before exposure to silver nitrate, no silver deposits are found.

Cyclin synthesis, modification and destruction during meiotic maturation of the starfish oocyte

The pattern of protein synthesis in oocytes of the starfish Marthasterias glacialis changes during 1-methyladenine-induced meiotic maturation. One of the newly synthesized proteins, a major 54-kDa polypeptide, was synthesized continuously after activation but was destroyed abruptly just before appearance of the polar bodies at each meiotic division. This protein thus resembles the cyclin proteins identified in cleaving sea urchin and clam embryos. RNA extracted from oocytes before and after maturation encoded virtually identical polypeptides when translated in the reticulocyte lysate. However there was poor correspondence between the in vitro translation products and the labeling pattern of intact cells. There was no exact in vitro counterpart to the in vivo-labeled cyclin. Instead, a major polypeptide of 52 kDA was seen which appears to be a precursor of the 54-kDa form of cyclin. The 52-kDa polypeptide was identified as cyclin by hybrid arrest of translation. Cyclin mRNA is not translated to a significant extent before oocyte activation and is present in oocytes as a nonadenylated form. It becomes polyadenylated when the oocytes mature. This behavior is also seen in the case of the mRNA for the small subunit of ribonucleotide reductase, another abundant maternal mRNA whose translation is activated at maturation.

Metabolic cooperation following fusion of starfish ootid and primary oocyte restores meiotic-phase-promoting activity

In the starfish Marthasterias glacialis, polyethylene glycol (PEG) homologous fused pairs consisting of two immature oocytes, blocked at the germinal vesicle stage, or two ootids, blocked at the female pronucleus stage, remain arrested at these specific stages, unless they are stimulated by the hormone 1-methyladenine. In contrast, heterologous pairs develop up to female pronucleus formation in the immature partner, indicating that maturation-promoting factor was formed under these conditions. Kinetics for this process, reconstitution of the nuclear envelopes after first polar body extrusion, and delaying effect of emetine argue for the existence of a true metabolic cooperation process requiring complementary factors present in each partner. The effect of inhibitors that penetrate the plasma membrane points to the possible involvement of endogenous proteases that may activate latent or neosynthesized maturation-promoting factor precursor and/or protein kinases.

Monoamine oxidase activity in tissues of the starfish marthasterias glacialis

1. Monoamine oxidase activity towards PEA and 5-HT has been shown radiochemically in radial nerves and pyloric caeca of the starfish Marthasterias glacialis. 2. Radial nerves show higher specific activities than pyloric caeca with both substrates and this is more evident with 5-HT. 3. Both in radial nerves and pyloric caeca MAO activity shows a higher affinity for PEA than for 5-HT. 4. Regardless of the substrate used, in both radial nerves and pyloric caeca deprenyl is a more effective inhibitor of MAO activity than clorgyline. 5. The inhibition curves obtained by either inhibitor are simple sigmoid curves, suggesting the presence of only one form of MAO.

Inositol 1,4,5-triphosphate microinjection triggers activation, but not meiotic maturation in amphibian and starfish oocytes

Inositol 3,4,5-triphosphate (InsP3) brought about cortical granule exocytosis and elevation of a fertilization membrane, due to a rapid increase of free calcium in cytoplasm, when injected into oocytes of the amphibian Xenopus laevis arrested at second meiotic metaphase. The same result was observed when injection was performed into oocytes of the starfish Marthasterias glacialis arrested either at the first meiotic prophase or after completion of meiosis. Although meiotic maturation was induced in both animals by specific hormones which have been previously shown to release Ca 2+ within cytoplasm, InsP3 microinjection into prophasearrested oocytes did not release them from prophase block.

Starfish saponins. Part 14. Structures of the steroidal glycoside sulphates from the starfish Marthasterias glacialis

The major sulphated asterosaponins, marthasterosides A1, A2, B, and C, isolated from the starfish Marthasterias glacialis, have been completely characterized. Marthasterosides A1 and A2 are hexaglycosides and contain the same aglycone, thornasterol A. They have been established as 6α-O-{β-D-fucopyranosyl-(1→3)-β-D-fucopyranosyl-(1→2)-β-D-galactopyranosyl-(1→4)-[β-D-quinovopyranosyl-(1→2)]-β-D-xylopyranosyl-(1→3)-β-D-quinovopyranosyl}-20-hydroxy-23-oxo-5α-cholest-9(11)-en-3β-yl sodium sulphate (6) and 6α-O-{β-D-fucopyranosyl-(1→3)-β-D-fucopyranosyl-(1→2)-β-D-quinovopyranpsyl-(1→4)-[β-D-quinovopyranosyl-(1→2)]-β-D-xylopyranosyl-(1→3)-β-D-quinovopyranosyl}-20-hydroxy-23-oxo-5α-cholest-9(11 )-en-3β-yl sodium sulphate (7) respectively. Marthasterosides B and C are the pentaglycosides (8) and (9); they contain the same oligosaccharide moiety, i.e. β-D-fucopyranosyl-(1→2)-β-D-fucopyranosyl-(1→4)-[β-D-quinovopyranosyl-(1→2)]-β-D-quinovo-pyranosyl-(1→3)-β-D-glucopyranosyl, which is attached to C-6 of 3β-sulphomarthasterone, i.e. 3β,6α-dihydroxy-5α-cholesta-9(11)24-dien-23-one, and of 3β-sulpho-24,25-dihydromarthasterone, respectively.

Intracellular microinjection of alkaline buffers reversibly inhibits the initial phase of hormone action in meiosis reinitiation of starfish oocytes

Intracellular microinjection of alkaline Hepes-KOH buffers, which increases intracellular pH (pH I) from 6.92 to 7.70 in fully grown prophase-blocked oocytes of the starfish Marthasterias glacialis, like external application of ammonia and other weak bases ( M. Doree, K. Sano, and H. Kanatani, 1982, Dev. Biol. 90, 13–17), inhibited meiosis reinitiation induced by 1-methyladenine (1-MeAde) or dithiothreitol (DTT), a mimetic of the hormone. Oocytes could be released from inhibition by raising the concentration of hormone or of its mimetic. Increasing pH I to 7.70 neither inhibited nor delayed meiosis reinitiation when pH was clamped after the end of the hormone-dependent period, the period during which 1-MeAde is required in the external medium for meiosis to occur, whereas it blocked the action of the hormone at low concentration when performed before the end of the hormone-dependent period. When hormone concentration was higher, germinal vesicle breakdown (GVBD) occurred, but duration of the hormone-dependent period was increased. Delay introduced by alkalinization for oocytes to reach GVBD after 1-MeAde addition was smaller at high than at medium concentrations of the hormone. Increasing pH I did not inhibit action of MPF, the cytoplasmic maturation factor which induces GVBD and the subsequent process of meiotic maturation following hormonal treatment of prophase-blocked oocytes.

The histone H2B from the sperm cell of the starfish Marthasterias glacialis.

A single species of histone H2B with a blocked N-terminus has been isolated from sperm of the starfish Marthasterias glacialis. The amino-terminal region of the histone H2BMarthasterias shows no similarity to the multiple forms of histones H2B found in the sperm of sea urchins, but there are distinct homologies to the histone of Patella granatina and that of the embryo of Parechinus angulosus. The sequence of the 90 carboxy terminal amino acids is highly conserved as in the other histones H2B.

A phosphorylated protein in KCl-Triton extracts of 1-methyladenine-treated cortices from oocytes of the starfish Marthasterias glacialis

A single phosphorylated molecule of 17,000 daltons has been identified in extracts of purified cortices of the starfish Marthasterias glacialis that were treated with 1-methyladenine in the presence of [ 32 P]ATP. This molecule appears to have been formed from a larger species of 150,000 daltons which was found in extracts of cortices that had not been treated with 1-methyladenine but not in extracts of 1-methyladenine-treated cortices. It appears that this phosphorylated molecule is a good candidate for further investigation as a maturation promoting factor.

Aggression by limpets against invertebrate predators

Small Patella oculus and P. granatina rapidly retreat from invertebrate predators but larger specimens are aggressive, and are capable of crushing predators with their shells. The size at which this transition occurs is specific to particular predators, comparatively small limpets attacking the whelk Thais dubia while only much larger individuals are aggressive to the starfish Marthasterias glacialis.

Breakdown and formation of high-energy phosphates and octopine in the adductor muscle of the scallop,Chlamys opercularis (L.), during escape swimming and recovery

1. The scallopChlamys opercularis uses jet propulsion swimming as a means of escape if attacked by the star fishMarthasterias glacialis. The energy for these rapid movements is supplied by the depletion of the phosphagen phospho-L-arginine. During escape swimming the energy charge of the adductor muscle drops from 0.93 to 0.42. Due to the decrease of phospho-L-arginine from 20.4 to 1.5 μmol/g fresh wt there is a concomitant increase of L-arginine from 14.7 to 34.7 μmol/g fresh wt. No octopine, D- or L-lactate was accumulated in exhausted animals. 2. During the first 30 min of recovery in aerated sea water, octopine, instead of lactate, is synthesized in adductor muscles. The energy charge rises to 0.92. Within 60 min the phospho-L-arginine pool is replenished and half of the accumulated octopine again metabolized. 3. During anaerobic revovery, i.e. when the scallops are kept exposed to air, octopine synthesis is pronounced (7.5 μmol/g fresh wt/h). The energy charge increases to 0.85. However, under these conditions no phospho-L-arginine is formed. 4. There is no evidence for transport of octopine from the adductor muscle to other tissues.

The Responses of South African Patellid Limpets to Invertebrate Predators

The starfish Marthasterias glacialis is a generalized predator, feeding particularly on Choromytilus meridionalis, but also on several limpets, notably Patella longicosta. Thais dubia (Gastropoda) feeds mainly on barnacles, mussels, and Patella granulans. The gastropods Burnupena delalandii and B. cincta are principally scavengers, feeding on damaged or dead animals. The responses of Patella spp. to these predators are described. P. granulans, P. concolor, P. compressa and P. miniata all retreat rapidly on contact. Small P. granatina and P. oculus respond similarly, but larger specimens react aggressively, smashing their shells downwards and often damaging the predator. The territorial species (P. longicosta, P. cochlear and P. tabularis) all retreat to their scars and remain clamped there. P. argenvillei and P. tabularis are usually unresponsive, possibly because they are too large to fall prey. Cellana capensis rolls its mantle upwards to cover the shell, preventing predators from attaching. The responses and their effectiveness are discussed in relation to other behavioural patterns displayed by limpets. There is no correlation between the intensity of a prey’s response to a predator and the degree of contact between the two in the field.

Studies on the distribution, biosynthesis and function of steroidal saponins in echinoderms

1. 1. Large quantities of saponin are present in the Asteroidea (starfish), with only trace amounts in the Ophiuroidea, Echinoidea and Crinoidea. 2. 2. The occurrence of large amounts of saponin coincides with the presence of free Δ 7-sterols. 3. 3. Saponins exert their toxic effects by interacting with cell membrane cholesterol, and do not interact with Δ 7-sterols to the same degree. 4. 4. A relationship exists between the taxonomic position of a starfish and the composition of its saponin aglycone fraction. 5. 5. The starfish Marthasterias glacialis can synthesize saponins both from [2- 14C] mevalonic acid and [4- 14C] cholesterol.

Partial characterization of a biologically active steroid glycosideisolated from the starfish Marthasterias glacialis.

1. A steroid glycoside (M(2)), which induces avoidance and other reactions in the mollusc Buccinum undatum, has been isolated from extracts of the starfish Marthasterias glacialis by ion-exchange chromatography. 2. The steroid glycoside was homogeneous by t.l.c. and contained glucose, quinovose, fucose and sulphate in the molar proportions 1:2:1:1, in addition to a water-insoluble aglycone. 3. The aglycone was identified as a cholestane derivative containing an unusual Delta(24)-23-ketone system, two secondary hydroxyl groups and an olefinic double bond, and had the molecular formula C(27)H(42)O(3). 4. The rates of release of sugars and sulphate suggested that fucose was at the non-reducing end of the oligosaccharide, with glucose glycosidically linked to the steroid. The sulphate group appeared to be linked to the other hydroxyl group of the steroid.

The Ecology of Lough Ine XVI. Predation and Diurnal Migration in the Paracentrotus Community

In various parts of Lough Ine the sea urchin Paracentrotus lividus Lamarck populates the shallow sublittoral from low water down to about 1 m below this level, and keeps the bottom clear of algae by its grazing (Kitching & Ebling 1961). The most extensive areas regularly occupied by Paracentrotus are along the north shore of the lough, on boulders and on solid rock, and in Curlew Bay, on shell gravel fringed at low water mark with rocks. The sea bed slopes gently at these localities, and predators are few. Of the larger crabs only Carcinus occurs commonly, and starfish normally remain in slightly deeper water. On the other hand, filter feeders are present in large numbersPomatoceros triqueter (L.) (Polychaeta), Anomia ephippium L. (Lamellibranchia) and (less abundantly) Chlamys varia (L.) (Lamellibranchia). There are also substantial numbers of the grazing gastropod Gibbula cineraria (L.). New patches, dominated by Paracentrotus and bare of algae, have recently developed in many parts of the lough, and especially in the South Basin. In these places the shore is steep and heaped with boulders. There are additional predators-the starfish Marthasterias glacialis (L.), Asterias rubens L. and Asterina gibbosa (Pennant) under the boulders, the crab Portunus puber (L.) as a nocturnal visitor, and occasionally also the edible crab, Cancer pagurus L. Grazing and filter-feeding molluscs are much less abundant. This paper is concerned with the ecological inter-relations of important members of the Paracentrotus community. We have attempted to formulate the system of food chains operating within the community, and to interpret diurnal migrations of some of its members in relation to predation.

Use of Plastic Tubing in Chromatography

DURING a chromatographic separation of the carotenoid pigments of the starfish Marthasterias glacialis (L.) from Madeira, it was found that some pigment disappeared during elution, which was necessarily prolonged in order satisfactorily to separate the relatively large number of pigments present in the total carotenoid extract. Several pigments were lost in this way (presumably owing to oxidation on the column), and further, some of the zones were so small as to make it difficult to isolate them by extruding the column.