Tube Feet Research Articles

Motoric impairment following manganese exposure in asteroid echinoderms

In the oceans, naturally occurring manganese (Mn) is released from the sediments during events of hypoxia. While neuro- and immuno-toxic effects of bioavailable manganese are well documented for crustaceans, studies of similar effects of manganese on other marine invertebrates are comparatively few. Here, we developed a new functional test “the repeated turning assay” to investigate if manganese exposure at ∼12mgL−1 affected motoric behaviour of two asteroid echinoderms, the Common sea star, Asterias rubens, and the Black brittle star, Ophiocomina nigra. By measuring of the turning-over capacity, from dorsal to ventral position, after one and two weeks of manganese exposure, we showed that for both species Mn exposure significantly delayed the ability to turn. After a recovery period of two weeks, the capacity of turning-over was not restored to that of unexposed animals neither for A. rubens nor for O. nigra. Further investigation of sea stars showed that Mn accumulated ∼5 fold in the tube feet, organs involved in their turning-over activity, and the high concentration remained after the recovery period. In the tube feet we also recorded an increased activity of acetylcholinesterase (AChE), here used as a proxy for neuromuscular disturbances. The results indicated that Mn induces neuromuscular disturbance in echinoderms which is important news, given that previous studies have concluded that adult echinoderms are relatively tolerant to Mn.

Fish-seastar facilitation leads to algal forest restoration on protected rocky reefs.

Although protected areas can lead to recovery of overharvested species, it is much less clear whether the return of certain predator species or a diversity of predator species can lead to re-establishment of important top-down forces that regulate whole ecosystems. Here we report that the algal recovery in a Mediterranean Marine Protected Area did not derive from the increase in the traditional strong predators, but rather from the establishment of a previously unknown interaction between the thermophilic fish Thalassoma pavo and the seastar Marthasterias glacialis. The interaction resulted in elevated predation rates on sea urchins responsible for algal overgrazing. Manipulative experiments and field observations revealed that the proximity of the seastars triggered an escape response in sea urchins, extending their tube feet. Fishes exploited this behavior by feeding on the exposed tube feet, thus impairing urchin movement, and making them vulnerable to predation by the seastars. These findings suggest that predator diversity generated by MPA establishment can activate positive interactions among predators, with subsequent restoration of the ecosystem structure and function through cascading consumer impacts.

An integrated transcriptomic and proteomic analysis of sea star epidermal secretions identifies proteins involved in defense and adhesion

Sea stars rely on epidermal secretions to cope with their benthic life. Their integument produces a mucus, which represents the first barrier against invaders; and their tube feet produce adhesive secretions to pry open mussels and attach strongly but temporarily to rocks. In this study, we combined high-throughput sequencing of expressed mRNA and mass-spectrometry-based identification of proteins to establish the first proteome of mucous and adhesive secretions from the sea star Asterias rubens. We show that the two secretions differ significantly, the major adhesive proteins being only present in trace amounts in the mucus secretion. Except for 41 proteins which were present in both secretions, a total of 34 and 244 proteins were identified as specific of adhesive secretions and mucus, respectively. We discuss the role of some of these proteins in the adhesion of sea stars as well as in their protection against oxygen reactive species and microorganisms. In addition, 58% of the proteins identified in adhesive secretions did not present significant similarity to other known proteins, revealing a list of potential novel sea star adhesive proteins uncharacterized so far. The panel of proteins identified in this study offers unprecedented opportunities for the development of sea star-inspired biomimetic materials.

Nucleotide sequence and expression of relaxin-like gonad-stimulating peptide gene in starfish Asterina pectinifera

Starfish gonad-stimulating substance (GSS) is the only known invertebrate peptide hormone responsible for final gamete maturation, rendering it functionally analogous to gonadotropins in vertebrates. Because GSS belongs to the relaxin-like peptide family, we propose renaming for starfish gonadotropic hormone as relaxin-like gonad-stimulating peptide (RGP). This study examined the primary structure and expression regulation of the RGP gene in starfish Asterina pectinifera. RGP consisted of 3896 base pairs (bp) divided over two exons, exon 1 of 208bp and exon 2 of 2277bp, and one intron of 1411bp. Promoter sequences, CAAT and TATA boxes, were present in the 5′-upstream region of the coding DNA sequence of RGP. The transcript was 2485 bases (b) in length. The AAUAAA polyadenylation signal was found in 3′-untranslated region over 2kb away from the stop codon. This showed that only 14% of the RGP mRNA was translated into the peptide, because a size of the open-reading frame was 351 b. Furthermore, an analysis by using real-time quantitative PCR with specific primers for RGP showed that mRNA of RGP was expressed at high levels in the radial nerves. Expression was also observed in the cardiac stomachs, although the level was low, and trace levels were detected in the gonads, pyloric caeca and tube feet. This result suggests that the RGP gene is transcribed mainly in the radial nerves of A. pectinifera.

Identification and characterization a novel transcription factor activator protein-1 in the sea cucumber Apostichopus japonicus.

The transcription factor activator protein-1 (AP-1) is an important gene expression regulator with typical Jun and region-leucine zipper (bZIP) domains and can respond to a plethora of physiological and pathological stimulus. In this study, we identified a novel AP-1 gene in Apostichopus japonicus by transcriptome sequencing and RACE approaches (designated as AjAP-1). The full-length of AjAP-1 was of 2944 bp including a 5' untranslated region (UTR) of 201 bp, a 3' UTR of 1753 bp and a putative open reading frame of 990 bp encoding a polypeptide of 329 amino acid residues. Two representative domains of Jun and bZIP as well as two nuclear localization signals (NLSs) were also detected in deduced amino acid of AjAP-1. Spatial distribution expression indicated that AjAP-1 was ubiquitously expressed in all examined tissues with predominant expression in the body wall, moderate in the tube feet, respiratory tree and colemocytes and slightly weak in the intestine and longitudinal muscle. Time-course expression analysis in intestine and coelomocytes revealed that AjAP-1 both reached its peak expression at 4 h after Vibrio splendidus challenge with a 2.6 and 8.2-fold increase compared to their control groups, respectively. Taken together, all these results suggested that AjAP-1 was a novel immune factor and might be involved in the processes of anti-bacteria response in sea cucumber.

The uptake of dissolved organic material by the sea cucumber Parastichopus californicus (Stimpson) and its potential role in visceral regeneration

The sea cucumber Parastichopus californicus atrophies and regenerates its internal organs on an annual cycle. Previous research has suggested that during the period of maximal regeneration (January–March) no movement or feeding occurs; however metabolic rate is doubled compared to non-regenerative periods (June–August). Uptake of dissolved organic material (DOM) from the aqueous environment could provide an external source of biosynthetic materials for regeneration of the internal organs. P. californicus were collected in the summer (actively moving and feeding, not degenerating or regenerating), winter (inactive, degenerating), and spring (inactive, regenerating). Animals were incubated in seawater containing a mixture of amino acids labeled with 15N and 13C. Incorporation of 15N (summer, winter, spring) and 13C (summer, spring) by the respiratory trees was significantly higher than incorporation by other types of tissues. Additionally, dorsal and ventral epidermis, oral tentacles, digestive tract, muscle, and tube feet incorporated 15N and/or 13C during at least one season. These results demonstrate that certain tissues, especially the respiratory trees, of P. californicus assimilate free amino acids from the sea water which could be used as biosynthetic materials for regeneration. These results also indicate that the respiratory trees may have a role in nutrition as well as respiration.

Long telomeres are associated with clonality in wild populations of the fissiparous starfish Coscinasterias tenuispina.

Telomeres usually shorten during an organism's lifespan and have thus been used as an aging and health marker. When telomeres become sufficiently short, senescence is induced. The most common method of restoring telomere length is via telomerase reverse transcriptase activity, highly expressed during embryogenesis. However, although asexual reproduction from adult tissues has an important role in the life cycles of certain species, its effect on the aging and fitness of wild populations, as well as its implications for the long-term survival of populations with limited genetic variation, is largely unknown. Here we compare relative telomere length of 58 individuals from four populations of the asexually reproducing starfish Coscinasterias tenuispina. Additionally, 12 individuals were used to compare telomere lengths in regenerating and non-regenerating arms, in two different tissues (tube feet and pyloric cecum). The level of clonality was assessed by genotyping the populations based on 12 specific microsatellite loci and relative telomere length was measured via quantitative PCR. The results revealed significantly longer telomeres in Mediterranean populations than Atlantic ones as demonstrated by the Kruskal-Wallis test (K=24.17, significant value: P-value<0.001), with the former also characterized by higher levels of clonality derived from asexual reproduction. Telomeres were furthermore significantly longer in regenerating arms than in non-regenerating arms within individuals (pyloric cecum tissue: Mann-Whitney test, V=299, P-value<10(-6); and tube feet tissue Student's t=2.28, P-value=0.029). Our study suggests that one of the mechanisms responsible for the long-term somatic maintenance and persistence of clonal populations is telomere elongation.

Physiological responses of the intertidal starfish Pisaster ochraceus, (Brandt, 1835) to emersion at different temperatures

The physiological responses of the intertidal starfish Pisaster ochraceus were recorded during 6h emersion in air at temperatures of 5°C, 15°C or 25°C, followed by a subsequent return to seawater (12–14°C). After 6h in 5°C air the body temperature of the starfish had equilibrated with the medium. In 15°C and 25°C air, evaporation across the body surface prevented equilibration, and the body temperature remained several degrees cooler than the air. In air, both oxygen consumption and CO2 production increased with increasing temperature. The oxygen consumption in air did not change when the body temperature of the starfish was similar to that of seawater (11–13°C), but appeared to be lower in the 25°C air treatment. This suggests that the relationship between oxygen consumption and water and air temperature is complex and both the magnitude of temperature change, and the duration of aerial exposure may influence oxygen consumption. The low respiratory quotient suggested that CO2 excretion was not complete, possibly due to collapse of the tube feet and aboral papulae in air. This leads to a temperature related increase in PCO2 and a concomitant acidosis in 15°C, and 25°C air. In 5°C air the PCO2 of the coelomic fluid did not increase significantly and there was no change in pH, possibly due to a temperature related pH increase. There was a slight increase in calcium ion levels in 15°C and 25°C air and a drop in 5°C air; in other species this represents a release of bicarbonate reserves from the exoskeleton, however, no compensation of the acidosis was observed for P. ochraceus. It is likely therefore that this was a passive dissolution of the exoskeleton caused by the acidosis, rather than an active compensatory mechanism. Ammonia and lactate levels were very low or below detection threshold in most specimens which is typical for echinoderms. The body temperature, gas levels and the pH of the coelomic fluid were rapidly regained when the animals were re-immersed in seawater of 12–14°C. Oxygen consumption remained higher during the recovery period, possibly reflecting the up-regulation of processes associated with cellular repair. The results of this study suggest that the physiological mechanisms reported here make P. ochraceus ideally suited for life in the intertidal zone.

Examination of the skeletal proteome of the brittle star Ophiocoma wendtii reveals overall conservation of proteins but variation in spicule matrix proteins.

BackgroundWhile formation of mineralized tissue is characteristic of many animal taxa, the proteins that interact with mineral are diverse and appear in many cases to be of independent origin. Extracellular matrix proteins involved in mineralization do share some common features. They tend to be disordered, secreted proteins with repetitive, low complexity. The genes encoding these proteins are often duplicated and undergo concerted evolution, further diversifying the repetitive domains. This makes it difficult to identify mineralization genes and the proteins they encode using bioinformatics techniques. Here we describe the use of proteomics to identify mineralization genes in an ophiuroid echinoderm, Ophiocoma wendtii (O. wendtii).ResultsWe have isolated the occluded proteins within the mineralized tissue of the brittle star Ophiocoma wendtii. The proteins were analyzed both unfractionated and separated on SDS-PAGE gels. Each slice was analyzed using mass spectroscopy and the amino acid sequence of the most prevalent peptides was obtained. This was compared to both an embryonic transcriptome from the gastrula stage when skeleton is being formed and a tube foot (an adult mineralized tissue) transcriptome. Thirty eight proteins were identified which matched known proteins or protein domains in the NCBI databases. These include C-type lectins, ECM proteins, Kazal-type protease inhibitors, matrix metalloproteases as well as more common cellular proteins. Many of these are similar to those found in the sea urchin Strongylocentrotus purpuratus (S. purpuratus) skeleton. We did not, however, identify clear homologs to the sea urchin spicule matrix proteins, and the number of C-type lectin containing genes was much reduced compared to sea urchins. Also notably absent was MSP-130.ConclusionsOur results show an overall conservation of the types of proteins found in the mineralized tissues of two divergent groups of echinoderms, as well as in mineralized tissues in general. However, the extensive gene duplication and concerted evolution seen in the spicule matrix proteins found in the sea urchin skeleton was not observed in the brittle star.Electronic supplementary materialThe online version of this article (doi:10.1186/s12953-015-0064-7) contains supplementary material, which is available to authorized users.

Color diversity and distribution of sea urchin Tripneustes gratilla in Cenderawasih Bay ecoregion of Papua, Indonesia

Tripneustes gratilla is a sea urchin with a variety of colors, which is associated with adaptability to the environment. The color diversity of sea urchin in the Cenderawasih Bay ecoregion has not been studied yet. Therefore, we investigated the habitat influences on color pattern and distribution of T. gratilla at Cenderawasih Bay. One hundred and seven individuals of T. gratilla were randomly collected in 5 different locations in Cenderawasih Bay. There are 35, 30, 13, 20 and nine individuals from Manokwari, Wasior, Biak, Nabire, and Yapen, respectively. The result showed the test (skeleton), spine, and tube feet color of T. gratilla in Cenderawasih Bay have 31 different colors. Tangency analysis indicated that the color diversity was associated with location site of T. gratilla at Cenderawasih Bay. Black-white is dominant test color of T. gratilla and occurs in all populations, whereas dark purple-orange only occurs in Wasior population. Five spine colors of T. gratilla were not uniformly distributed in all populations. The white color spine is dominant and occurs at all locations while reddish orange occurs only in Wasior. Moreover, the color of tube feet is very influenced by the environment.

Structural Behavior of Thin-Walled Concrete-Filled Steel Tube Used in Cable Tunnel: An Experimental and Numerical Investigation

One steel grid and five thin-walled concrete-filled steel tubes (CTST) used as the supports of tunnel were tested in site for investigating the mechanical behavior. The mechanical influences of thickness, node form, and concrete on CTST were gained and compared with the impacts on steel grid. It is indicated that high antideformation capacity of CTST improved the stability of surrounding rock in short time. The cementitious grouted sleeve connection exhibited superior flexibility when CTST was erected and built. Although the deformation of rock and soil in the tunnel was increasing, good compression resistance was observed by CTST with the new connection type. It was also seen that vault, tube foot, and connections were with larger absolute strain values. The finite element analysis (FEA) was carried out using ABAQUS program. The results were validated by comparison with experimental results. The FE model could be referred by similar projects.

A Prejudiced Review of Ancient Parasites and Their Host Echinoderms: CSI Fossil Record or Just an Excuse for Speculation?

Recognizing the presence of a parasite and identifying it is a relatively straightforward task for the twenty-first century parasitologist. Not so the pursuit of ancient parasites in fossil organisms, a much more difficult proposition. Herein, Boucot's seven-tiered scheme of reliability classes is applied as a measure of confidence of the recognition of putative parasitism in two echinoderm classes, Upper Palaeozoic crinoids and a Cretaceous echinoid (high confidence is 1, low confidence 7). Of the five examples, the parasitic(?) organism is preserved in only two of them. A zaphrentoid coral on the camerate crinoid Amphoracrinus may have robbed food from the arms (Category 1 or 2B). A pit in what appears to be a carefully selected site on the disparid crinoid Synbathocrinus is associated with a growth deformity of the cup (Category 4). Multiple pits in an Amphoracrinus theca are also associated with a deformed cup, but it is more difficult to interpret (Category 4 or 7). Some specimens of the camerate crinoid Neoplatycrinites have circular grooves or depressions posteriorly, presumably produced by coprophagic/parasitic platyceratid gastropods (Category 1). Site selectivity of pits in the echinoid Hemipneustes places them preferentially adjacent to respiratory tube feet (Category 4). From these examples it is deduced that sparse infestations of borings or epizoozoic organisms permit a more confident interpretation of organism/organism interactions; dense accumulations, possibly following multiple spatfalls, mask such patterns.

Symmetry, asymmetry, and dissymmetry in echinoids

The development of bilateral symmetry of echinoid test in the course of exocyclization and phenomena of dissymmetry in the structure of paired interambulacra and apical system are examined. Peculiar metamery is typical of ambulacra, some plates of which are characterized by the similarity symmetry. The operation of translation in each ambulacrum results in the identity of form; however, it does not provide equal coincidence of each plate. The considerable asymmetry of petaloids in some irregular echinoids results from different functions of tube feet in adjacent petaloid rows.

The effect of copper and temperature on juveniles of the eurybathic brittle star Amphipholis squamata – Exploring responses related to motility and the water vascular system

The limited availability of test organisms that represent tropical and deeper water environments is a significant concern when assessing the risk of contaminants in these environments. Amphipholis squamata (Delle Chiaje 1828) is a widely distributed brittle star with many phylogenetic clades reported from different latitudes, and it also occurs from the intertidal zone to a depth of ∼1300m. In the present study, the effect of copper on four behavioural responses and mortality of A. squamata were quantified at four different temperatures including 25, 20, 15 and 10°C. At 25°C the four behavioural responses and mortality were relatively sensitive to copper, with 96h EC50 values of 25 (confidence interval 18–44), 24 (7–26), 32 (24–41), 29 (9–41)μgL−1 for the measured ability to turn from the oral surface up to oral surface down, curling behaviour, tube foot movement, and tube foot retraction respectively. The average 96-h LC50 value for copper at 25°C was 46μgL−1. Some endpoints investigated showed significant effects of reduced temperature compared to the optimal temperature. These effects were enhanced with increasing copper concentrations and significant differences in copper toxicity between temperature treatments were most notable when measuring the ability to turn from the oral surface up to oral surface down where the EC50 changed from 25 (18 to 44) to 6 (−18 to 14) μgL−1 with a reduction of temperature from 25 to 15°C. The results showed that A. squamata is relatively sensitive to copper and that further investigation into the effects of other stressors on these endpoints is warranted.

Characterization and expression analysis of microRNAs in the tube foot of sea cucumber Apostichopus japonicus.

MicroRNAs (miRNAs) are a class of endogenous non-coding small RNA with average length of 22 nucleotides, participating in the post-transcriptional regulation of gene expression. In this study, we report the identification and characterization of miRNAs in the tube foot of sea cucumber (Apostichopus japonicus) by next generation sequencing with Illumina HiSeq 2000 platform. Through the bioinformatic analysis, we identified 260 conserved miRNAs and six novel miRNAs from the tube foot small RNA transcriptome. Quantitative realtime PCR (qRT-PCR) was performed to characterize the specific expression in the tube foot. The results indicated that four miRNAs, including miR-29a, miR-29b, miR-2005 and miR-278-3p, were significantly up-regulated in the tube foot. The target genes of the four specifically expressed miRNAs were predicted in silico and validated by performing qRT-PCR. Gene ontology (GO) and KEGG pathway analyses with the target genes of these four miRNAs were conducted to further understand the regulatory function in the tube foot. This is the first study to profile the miRNA transcriptome of the tube foot in sea cucumber. This work will provide valuable genomic resources to understand the mechanisms of gene regulation in the tube foot, and will be useful to assist the molecular breeding in sea cucumber.

Expression of c-type lysozyme gene in sea cucumber (Apostichopus japonicus) is highly regulated and time dependent after salt stress.

Lysozymes have been confirmed to possess varieties of functions in a range of organisms. In the present study, we cloned and sequenced c-type lysozyme cDNAs, constructed the recombinant protein over-expression of c-type lysozyme and analyzed the expression of transcription level in various tissues. The c-type lysozyme cDNA contained an open reading frame of 759bp encoding a polypeptide of 252 amino acids. The molecular weight of the deduced amino acid of AjcLYZ is 26.7kDa with an estimated pI of 4.66. Multiple sequence alignments revealed that AjcLYZ had two highly conserved active sites (Glu147 and Asp159) and eight typical Cys residues. The tertiary structure and modeled AjcLYZ showed structural similarity to Meretrix lusoria LYZ. The results of mRNA transcripts showed that the highest expression was found in the tube foot, followed by the muscle, body wall, and coelomic fluid. In contrast, the intestine, tentacle and respiratory tree exhibited very low expression levels. Under salinity stress, significant down-regulation of AjcLYZ was observed in response to salinity stress in the intestine and coelomic fluid. Significant up-regulation and down-regulation of AjcLYZ were observed in response to salinity stress in body wall and respiratory tree. The purified recombinant protein was analyzed by SDS-PAGE and a single band with a molecular mass of 45.09kDa, which was in agreement with the theoretical size (26.7kDa for AjcLYZ and 18.39kDa Trx-His-S tags) of the recombinant protein. Radial diffusion assay was employed to determine the antimicrobial spectrum of recombinant AjcLYZ against three Gram-positive and Gram-negative bacteria, and three sea cucumber pathogenic Vibrio species. From the radius of the antimicrobial zone, it was found that recombinant AjcLYZ harbored remarkable in vitro inhibitive effect on tested Gram-positive bacteria, while lytic activity against Gram-negative bacteria was relatively weak. The results will provide new clues about the molecular mechanisms that regulate the salinity adaption system.

아무르불가사리 추출물의 생리활성

아무르불가사리(Asterias amurensis)의 6가지의 조직 추출물들을 사용하여 항균활성, 항산화 활성 및 평활근에 대한 수축과 이완반응에 대한 활성을 측정하였다. 1% (v/v) 초산용액을 사용하여 동결 건조한 샘플들을 추출하여 각각의 활성측정에 사용한 결과, 껍질을 제외한 모든 조직 추출물들은 E. coli D31에 대해 강한 항균활성을 나타내었고, 근육 및 장관 추출물들은 별불가사리(Asterina pectinifera)의 DRM에 대해 수축반응을 나타냈다. 한편, 오징어(Todarodes pacificus) 식도에 대한 수축반응은 실험에 사용한 모든 조직 추출물들에서 검출되었다. 특히, 간 추출물의 수축활성은 다른 조직의 추출물의 활성에 비해 더 높았다. 뿐만 아니라 간, 근육 및 소화관 추출물은 졸복(Takifugu pardalis)의 장관에 대해서 수축반응을 나타냈다. 별불가사리의 DRM에 대한 이완반응은 실험에 사용한 모든 조직 추출물들에서 활성을 나타냈다. 항산화 활성은 장관, 간 및 껍질의 추출물들에서 강하게 나타났다. 따라서 아무르불가사리는 새로운 생체기능 조절물질의 발견에 대한 가능성을 지닌 자원이라는 것을 본 연구의 결과들은 제시한다. Nowadays, starfish is one of problems about interruption of marine ecosystem, so many researchers are focusing on application of the starfish (Asterias amurensis). In this study, we investigated the contractile and relaxant activity of the smooth muscles and the antimicrobial and antioxidant activity of six different tissues (muscle, gut, liver, tube feet, gonads, and body) of A. amurensis. Frozen samples were extracted with distilled water containing 1% acetic acid. Extracts from all the tissues, except the body tissue, showed potent antimicrobial activity against Escherichia coli D31. The dorsal retractor muscles (DRM) of muscle and gut extracts showed strong contraction responses. On the other hand, contractile activity on esophagus of squid Todarodes pacificus could be detected in all tissues tested. The contractile activity of the liver extract was higher than that of the other tissues. The body, tube feet, and liver extracts showed the contractile activity on the intestine of the panther puffer fish (Takifugu pardalis). Relaxation response on the DRM of starfish (A. pectinifera) was observed in all tissues tested. Increased antioxidant activity was observed in the gut, liver, and body extracts. The results suggest that the starfish (A. amurensis) is a potential source of novel bioactive compounds.

아무르 불가사리(Asterias amurensis)의 관족으로부터 신경성 펩타이드의 분리 및 정제

Two neuropeptides were purified from the acidified tube feet extract of the starfish Asterias amurensis by C18 reversed phase and size-exclusion high-performance liquid chromatography (HPLC). The tube feet extract and the purified peptides (AST-I and AST-II) showed potent contractile activity on dorsal retractor muscle (DRM) of the starfish Asterina pectinifera and intestine (smooth muscle) of the panther puffer Takifugu pardalis. Treatment of the purified peptides with dithiothreitol (DTT) for 60 min at <TEX>$37^{\circ}C$</TEX> significantly altered their retention times, suggesting that these compounds contained disulfide bonds. The molecular weights of AST-I and AST-II were determined to be 2064.2 Da and 6137.2 Da, respectively, by MALDI-TOF mass spectrometry.

별 불가사리(Asterina pectinifera) 조직별 초산추출물의 생리활성 탐색

The present study was performed to examine the contraction and relaxation responses of the smooth muscles, and search for antimicrobial and antioxidant activities in the tissues, of the starfish Asterina pectinifera. Frozen samples were extracted with distilled water containing 1% acetic acid. Extracts from all tissues showed potent antimicrobial activity against Escherichia coli D31. Relatively high levels of antimicrobial activity were also detected in the body extracts. Liver, tube feet, and body extracts caused contraction responses in the dorsal retractor muscles (DRM) of the starfish. In contrast, all tissues examined exhibited contractile activity in the esophagus of squid Todarodes pacificus. In addition, liver and gonad extracts caused contraction responses upon application to the intestine of the puffer fish Takifugu pardalis. Relaxation effects on the DRM of starfish were identified in most of the extracts, while no relaxant activity was detected in body extracts. Extracts from all tissues examined also exhibited antioxidant activities. The results of this study suggest that starfish are a potential source of novel bioactive compounds.

Sea star tenacity mediated by a protein that fragments, then aggregates.

Sea stars adhere firmly but temporarily to various substrata as a result of underwater efficient adhesive secretions released by their tube feet. Previous studies showed that this material is mainly made up of proteins, which play a key role in its adhesiveness and cohesiveness. Recently, we solubilized the majority of these proteins and obtained 43 de novo-generated peptide sequences by tandem MS. Here, one of these sequences served to recover the full-length sequence of Sea star footprint protein 1 (Sfp1), by RT-PCR and tube foot transcriptome analysis. Sfp1, a large protein of 3,853 aa, is the second most abundant constituent of the secreted adhesive. By using MS and Western blot analyses, we showed that Sfp1 is translated from a single mRNA and then cleaved into four subunits linked together by disulphide bridges in tube foot adhesive cells. The four subunits display specific protein-, carbohydrate-, and metal-binding domains. Immunohistochemistry and immunocytochemistry located Sfp1 in granules stockpiled by one of the two types of adhesive cells responsible for the secretion of the adhesive material. We also demonstrated that Sfp1 makes up the structural scaffold of the adhesive footprint that remains on the substratum after tube foot detachment. Taken together, the results suggest that Sfp1 is a major structural protein involved in footprint cohesion and possibly in adhesive interactions with the tube foot surface. In recombinant form, it could be used for the design of novel sea star-inspired biomaterials.