© 2002 by The Society for Integrative and Comparative Biology
Biomechanics of Adhesion in Sea Cucumber Cuvierian Tubules (Echinodermata, Holothuroidea)1
1 Marine Biology Laboratory, University of Mons-Hainaut, 6 Avenue du Champ de Mars, B-7000 Mons, Belgium
2 Marine Biology Laboratory, Free University of Brussels, 50 Avenue F.D. Roosevelt, B-1050 Brussels, Belgium
 |
SYNOPSIS |
|---|
TOP
 SYNOPSIS INTRODUCTIONMATERIAL AND METHODSRESULTSDISCUSSIONReferences |
|---|
Several species of sea cucumbers, all belonging to a single family, possess a peculiar and specialized defense system, the Cuvierian tubules. It is mobilized when the animal is mechanically stimulated, resulting in the discharge of a few white filaments, the tubules. In seawater, the expelled tubules lengthen considerably and become sticky upon contact with any object. The adhesiveness of their outer epithelium combined with the tensile strength of their collagenous core make Cuvierian tubules very efficient at entangling and immobilizing most potential predators. We have designed a method to measure the adhesion of holothuroid Cuvierian tubules. Tubule adhesive strength was measured in seven species of sea cucumbers belonging to the genera Bohadschia, Holothuria and Pearsonothuria. The tenacities (force per unit area) varied from 30 to 135 kPa, falling within the range reported for marine organisms using non-permanent adhesion. Two species, H. forskali and H. leucospilota, were selected as model species to study the influence of various factors on Cuvierian tubule adhesive strength. Tubule tenacity varied with substratum, temperature and salinity of the seawater, and time following expulsion. These differences give insight into the molecular mechanisms underlying Cuvierian tubule adhesion. Tenacity differences between substrata of varying surface free energy indicate the importance of polar interactions in adhesion. Variation due to temperature and time after expulsion suggests that an increase of tubule rigidity, presumably under enzymatic control, takes place after tubule elongation and reinforces adhesion by minimizing peeling effects.
|
INTRODUCTION |
|---|
|
TOP
SYNOPSISINTRODUCTIONMATERIAL AND METHODSRESULTSDISCUSSIONReferences |
|---|
Cuvierian tubules are peculiar organs found in several species of holothuroids (sea cucumbers), all belonging exclusively to the family Holothuriidae (Smiley, 1994
; Lawrence, 2001). Two main types of Cuvierian tubules can be distinguished, smooth and lobulated (Lawrence, 2001). The smooth tubules occurring in holothuroids of the genera Bohadschia, Holothuria and Pearsonothuria are expelled as sticky white threads that function in defense against predators (VandenSpiegel and Jangoux, 1987; Hamel and Mercier, 2000). On the other hand, the lobulated tubules occurring in holothuroids of the genus Actinopyga are never expelled and are not sticky (VandenSpiegel and Jangoux, 1993). The question remains, therefore, whether these tubules also function defensively (Lawrence, 2001).
Smooth Cuvierian tubules occur in great numbers (between 200 and 600 in H. forskali; VandenSpiegel and Jangoux, 1987) in the posterior part of the body cavity of the holothuroid. Proximally they are attached to the basal part of the left respiratory tree and their distal, blind ends float freely in the coelomic fluid. When irritated, the sea cucumber directs its aboral end toward the stimulating source and undergoes a general body contraction (Fig. 1). The anus opens, the wall of the cloaca tears, and the free ends of a few tubules (usually 10 to 20 in H. forskali; VandenSpiegel and Jangoux, 1987), together with coelomic fluid, are expelled through the tear and the anus. As water from the respiratory tree is forcefully injected into their lumen, the emitted tubules elongate up to 20 times their original length (VandenSpiegel and Jangoux, 1987). Upon contact with any surface, the elongated tubules instantly are sticky. The adhesiveness of Cuvierian tubules combined with their tensile strength make them very efficient at entangling and immobilizing most potential predators (VandenSpiegel and Jangoux, 1987; Hamel and Mercier, 2000). Finally, the expelled tubules autotomize at their attachment point on the left respiratory tree and are left behind as the holothuroid crawls away (VandenSpiegel and Jangoux, 1987). After expulsion and autotomy, Cuvierian tubules are readily regenerated. The regeneration of a complete set of tubules takes 15 to 18 days in H. leucospilota (Hamel and Mercier, 2000) and about five weeks in H. forskali (VandenSpiegel et al., 2000). Smooth Cuvierian tubules thus constitute an efficient defensive mechanism. Their large number, sparing use and regeneration dynamics make them a formidable line of defense (Hamel and Mercier, 2000; VandenSpiegel et al., 2000).
|
Most of the ultrastructural information available on Cuvierian tubules comes from VandenSpiegel and Jangoux (1987)
, who clarified much of the structure and function of these organs in the temperate species Holothuria forskali. The tubules consist of, from the inside to the outside, an inner epithelium surrounding the narrow lumen, a thick connective tissue layer and a mesothelium lining the surface of the tubule that is exposed to the coelomic cavity. The inner epithelium consists of cells enclosing large heterogeneous spherules composed of proteinic and glucidic fractions (Guislain, 1953; VandenSpiegel and Jangoux, 1987). The connective tissue layer encloses up to six imbricated collagen helices, each of them being parallel to the long axis of the tubule. It also includes longitudinal and circular muscle fibers. The mesothelium is the tissue layer responsible for adhesion. In quiescent tubules, it is a pseudostratified epithelium made up of two superposed cell layers, an outer layer of peritoneocytes and an inner layer of granular cells which is highly folded along the long axis of the tubule. Granular cells are filled with densely packed membrane-bound granules enclosing a proteinaceous material (Endean, 1957; VandenSpiegel and Jangoux, 1987). During elongation, the structure of the Cuvierian tubule is modified (VandenSpiegel and Jangoux, 1987). The inner epithelium is dissociated and the spherule contents are released, the helices of collagen fibers in the connective tissue layer are stretched, and, at the level of the mesothelium, the protective outer layer of peritoneocytes disintegrates and the granular cell layer, now unfolded, thus becomes outermost on the tubule. Granular cells empty the contents of their granules when the elongated tubule comes into contact with a surface, resulting in adhesion (VandenSpiegel and Jangoux, 1987; De Moor et al., 2003).
The single biochemical study published on Cuvierian tubule adhesive left on the substratum after mechanical detachment of the tubule in H. forskali shows it to be composed of 60% protein and 40% carbohydrate (De Moor et al., 2003). The proteinic nature of the adhesive material is confirmed by tests on the influence of various reagents on the adhesive strength of Cuvierian tubules of H. forskali, tubule adhesion being reduced by several proteolytic enzymes (Müller et al., 1972; Zahn et al., 1973). The Cuvierian tubule adhesive is highly insoluble, suggesting that it consists of proteins that are cross-linked. Only a small fraction of this material can be extracted using denaturing buffers and this soluble fraction contains several proteins with different molecular masses but with closely related amino acid compositions, rich in acidic and small side-chain amino acids (De moor et al., 2003).
The adhesion of Cuvierian tubules is remarkable in several respects. The composition of the adhesive is unique among the adhesive secretions of marine invertebrates (De Moor et al., 2003). Moreover, adhesion is achieved in a matter of seconds (less than 10 sec; Zahn et al., 1973). Paradoxically, only two biomechanical studies have been published on these intriguing organs, focusing primarily on the influence of various chemical reagents on the shear adhesive strength of Cuvierian tubules attached to a paraffin wax substratum (Müller et al., 1972; and Zahn et al., 1973; respectively). Moreover, both studies concerned the European species H. forskali. There is therefore a clear lack of information regarding the biomechanics of Cuvierian tubules in other species of sea cucumbers. The aim of the present work was to measure the adhesive strength of Cuvierian tubules in different species of holothuroids and also to investigate the influence of different physical factors on tubule adhesion. Indeed, variations of tenacity under different conditions may give insights into the molecular mechanism of Cuvierian tubule adhesion.
|
MATERIAL AND METHODS |
|---|
|
TOP
SYNOPSISINTRODUCTIONMATERIAL AND METHODSRESULTSDISCUSSIONReferences |
|---|
Sea cucumber collection and maintenance
Seven holothuroid species collected from the Mediterranean Sea and the Indian Ocean were used in this study.
Individuals of Holothuria forskali (Delle Chiaje, 1823) were collected at depths ranging from 10 to 20 m by SCUBA in Banyuls-sur-Mer (Pyrénées-Orientales, France). They were transported to the Marine Biology Laboratory of the University of Mons-Hainaut, where they were kept in marine aquaria with recirculating seawater systems (13°C, 33
salinity).
Specimens of Bohadschia marmorata Jaeger, 1833, B. subrubra (Quoy and Gaimard, 1833) and Pearsonothuria graeffei (Semper, 1868) were collected at depths ranging from 10 to 30 m by scuba diving at the south point of the Great Reef of Toliara (Madagascar). Individuals of Holothuria impatiens (Forskål, 1775), H. leucospilota (Brandt, 1835) and H. maculosa Pearson, 1913 were hand-collected at low tide on the crest of the Great Reef of Toliara. Individuals of all these species were transported to the "Institut Halieutique et des Sciences de la Mer" (IH.SM, Toliara), where they were kept in marine aquaria with recirculating seawater systems (28°C, 31 salinity).
Tenacity measurements of Cuvierian tubules
The discharge of Cuvierian tubules was induced mechanically by pinching the dorsal integument of the specimens with forceps. The expelled tubules were collected in glass Petri dishes (diameter 15 cm) filled with seawater (Fig. 2A). The adhesive strength of the tubules was measured with a digital force gauge (Mecmesin AFG 10N) fitted either to a manual test stand (Mecmesin MDD) or to a motorized test stand (Mecmesin VersaTest). This force gauge was accurate to the nearest 0.001N. A circular glass coverslip (diameter 1 cm) was glued to a nut and bolted on the rigid stainless steel rod (10 cm in length) connected to the force gauge (Fig. 2A). The force gauge was lowered at constant speed (12 mm/min) until a straight portion of tubule was compressed between the coverslip and the bottom of the Petri dish (see Results). Care was taken to ensure that the tubule was crossing the coverslip through its center. Then, the force gauge was elevated at constant speed (see Results) and the maximal force required to separate the two glass surfaces was recorded (Fig. 2B, C).
|
Generally, between 5 and 10 measurements could be made on the different Cuvierian tubules adhering to the Petri dish after which the tubules were mechanically removed using fine forceps, leaving 1 cm long rectangular prints at the locations where measurements were made. These prints, which are made up of adhesive material, were stained with Coomassie blue R-250 (0.125% solution in 50% methanol, 10% acetic acid). The width of each print was measured using a dissecting microscope equipped with a graduated eyepiece. The cross-sectional area of tubule attachment was determined by the product of length of tubule attached to the coverslip times the tubule width. The length was 1 cm (i.e., diameter of the coverslip) whereas the compressed tubule width was considered to equal the measured print width (Fig. 2C). The surface areas calculated in this way were slightly overestimated because the curved perimeter of the coverslip was not taken into account. However, the differences were minor (generally <1%) and never in excess of 2.5%. To calculate the tenacity (expressed in kPa) the different forces recorded for one Petri dish were then divided by the mean print surface area for this Petri dish. The process was repeated with at least three different individuals until a minimum of 30 measurements had been taken. Comparisons between Cuvierian tubule tenacities were performed using one-way analysis of variance (ANOVA) followed by the multiple comparison test of Tukey (Zar, 1984
). The level of significance was set at 
= 0.05. As far as possible tenacity measurements were carried out on freshly collected sea cucumbers because it was noted that the tenacity of the Cuvierian tubules typically decreased with time spent in captivity. However, this variability was not taken into account when we investigated the influence of physical factors on tubule tenacity. Indeed, each experiment was conducted over a very limited time period (1 or 2 days), with a single set of sea cucumbers and, each time, with an internal control consisting of measurements made under the standard conditions.
|
RESULTS |
|---|
|
TOP
SYNOPSISINTRODUCTIONMATERIAL AND METHODSRESULTSDISCUSSIONReferences |
|---|
Standardization of the tenacity measurement method
One of the goals of the present study was to develop a simple and reproducible method to measure Cuvierian tubule adhesion forces. The method had to be amenable to the field working conditions in Madagascar. All the experiments performed to standardize the measurement method were done on the European species Holothuria forskali.
Preliminary experiments indicated that the Cuvierian tubule adhesion forces measured depend on the force with which the tubule is first compressed. Indeed, tubule tenacity showed a sigmoid relationship with the compression force (Fig. 3A). Compression forces above 2 N produced tubule tenacities (>40 kPa) significantly higher than those produced following compression forces below 2 N (tenacities <10 kPa). In our measurement method, the compression force was set to 5 N to ensure that maximal tubule adhesion was being measured.
|
The second parameter tested was the speed at which the two surfaces compressing the tubule were separated. Within the range of velocities tested (between 12 and 500 mm/min), the Cuvierian tubule tenacity increased asymptotically and reached a plateau at a separation speed of about 100 mm/min (Fig. 3B). The adhesion strength measured at an unloading rate of 12 mm/min was significantly lower than those measured at the other rates (Table 1). However, this velocity was chosen as the standard measurement velocity because it was the only one that could be easily reproduced with the manual test stand used in Madagascar.
|
Interspecific variation of Cuvierian tubule adhesion
Adhesion forces of Cuvierian tubule on glass were measured in seven holothuroid species belonging to three different genera: Bohadschia marmorata, B. subrubra, Holothuria impatiens, H. leucospilota, H. maculosa and Pearsonothuria graffei, all from the Indian Ocean (Madagascar), and H. forskali from the Mediterranean Sea (France). It was observed that individuals of P. graeffei, whatever the mechanical stimulus applied to them, never discharged their Cuvierian tubules. They were therefore anaesthetized in a 7.5% solution of MgCl2 in distilled water before being dissected. Their tubules were collected, manually stretched by pulling on their extremities and placed in the Petri dishes.
In our experimental conditions, Cuvierian tubule adhesion force ranged from about 0.5 N in H. forskali to about 2 N in H. leucospilota, but averaged about 1 N in most other species (Fig. 4A). Cuvierian tubules were thinner in the species of the genus Holothuria than in those of the genera Bohadschia and Pearsonothuria. Indeed, in the former tubule print widths ranged from 1.5 to 2 mm whereas in the latter they ranged from 3 to 4 mm (Fig. 4A). However, no correlation was found between Cuvierian tubule thickness and the adhesion forces measured (r2 = 0.001).
|
Significant differences in tenacity were observed between the species examined (Table 1). Cuvierian tubules from H. leucospilota showed the highest mean tenacity of about 135 kPa (Fig. 4B). The mean tenacities of the tubules from the two other tropical species of Holothuria (about 50 kPa in H. impatiens and 63 kPa in H. maculosa) were less than half that of the tubules of H. leucospilota (Fig. 4B). Finally, Cuvierian tubules from the other species investigated had similar tenacities, ranging from about 30 to 40 kPa (Fig. 4B).
Factors influencing Cuvierian tubule tenacity
We investigated several physical factors suspected to influence Cuvierian tubule tenacity. For practical reasons, most of these experiments were conducted on the tubules of the European species H. forskali. Two of these experiments were repeated with the tropical species showing the highest tubule tenacity, H. leucospilota. The factors investigated were the substratum type to which the tubules adhered, the temperature and salinity of the seawater and the time elapsed between tubule expulsion and the force measurement.
In the experiment in which the type of substratum was varied, a large plaque consisting of the substratum material was attached to the bottom of the Petri dish and a small square plaque (1 cm x 1 cm) of the same material was attached to the steel rod of the force gauge. In addition to glass, the substrata chosen were stainless steel, paraffin wax, polyethylene and polystyrene. Cuvierian tubule tenacities measured on glass and stainless steel were about an order of magnitude higher than those measured on the three other substrata (Fig. 5A; Table 1).
|
Holothuria forskali; 
Holothuria leucospilota); (C) relationship between the mean tenacity (±SE) of Cuvierian tubules of Holothuria forskali and the salinity of seawater; (D) relationship between the mean tenacity (±SE) of Cuvierian tubules and the time elapsed after their expulsion (Tenacity of Cuvierian tubules also varied with seawater temperature and salinity (Fig. 5B and C). Temperature of the seawater in the Petri dish was controlled by working in a cold room for temperatures below room temperature, and by placing the Petri dish on a hot plate for temperatures above room temperature. The salinity was adjusted by adding either deionized water or salt (NaCl) to seawater from the aquarium. The temperature experiment was conducted both on H. forskali and on H. leucospilota. Each species showed an optimum temperature range (i.e., about 14–21°C for H. forskali and about 26–31°C for H. leucospilota; Fig. 5B) at which Cuvierian tubule tenacity was maximal (Table 1). These optimum temperature ranges were close to the seawater temperature ranges in the environment where the animals were collected. Cuvierian tubule adhesive strength in H. forskali was also significantly influenced by seawater salinity (Table 1). Tubule tenacity was maximum at salinities around 30
(Fig. 5C). Cuvierian tubules did not adhere to the glass substratum in deionized water (0 salinity). The influence of the elapsed time between Cuvierian tubule expulsion and force measurement was investigated in H. forskali and H. leucospilota. The expelled and elongated tubules were kept in the Petri dish for various periods of time before the force measurements took place. During this time, however, they were not sticking to the Petri dish bottom. In the two species, the tubule adhesive strength increased during the first one or two hours after expulsion and thereafter decreased until the tubules were no longer sticky (Fig. 5D). The initial increase in tenacity was significant in H. forskali, but not in H. leucospilota (Table 1).
|
DISCUSSION |
|---|
|
TOP
SYNOPSISINTRODUCTIONMATERIAL AND METHODSRESULTSDISCUSSIONReferences |
|---|
The measurement of the adhesive strength of marine invertebrates and of its variation under different conditions may give clues to the mechanisms of marine bioadhesion. Among marine invertebrate adhesive systems, the Cuvierian tubules of sea cucumbers are still a poorly understood model. In this study we designed a method to measure the adhesion of holothuroid Cuvierian tubules. Cuvierian tubule adhesive strength on glass was measured in seven species of sea cucumbers belonging to the genera Bohadschia, Holothuria and Pearsonothuria. The calculated tenacities varied from about 30 to 135 kPa. These tenacities fall within the range of adhesive strengths reported for marine organisms (see Walker, 1987
, for review). However, they lie among the lowest values observed, being closer to the tenacity of organisms using non-permanent adhesion than that of sessile marine invertebrates using permanent adhesion (Flammang, 1996). Tubule adhesion forces were similar for the holothuroid species examined here. In terms of tenacity, however, Cuvierian tubule adhesion was higher in species of the genus Holothuria than in species of Bohadschia and Pearsonothuria because the tubules were thinner in the former genus. Two species can be distinguished by their Cuvierian tubule adhesion: tubules of H. leucospilota showed the significantly highest adhesion force and tenacity while those of H. forskali had the lowest adhesion force and one of the lowest tenacities. So far, these variations within the genus Holothuria remain unexplained. It is noteworthy however that H. forskali, compared with the other species investigated, lives in temperate waters. The Cuvierian tubules of P. graeffei are also an enigma. Individuals of this species never discharged their tubules no matter what stimulation is applied to them. Yet, their tubules seem perfectly functional. They can elongate and their adhesive properties are identical to those of the Cuvierian tubules in the genus Bohadschia.
In H. forskali, we observed that the tenacity of Cuvierian tubules shows a sigmoid relationship with the compression force applied to the tubule prior to measurement. This presumably indicates that a minimum compression is required to ensure that sufficient tubule surface comes into contact with the substratum.
Cuvierian tubule tenacity in H. forskali is also positively correlated with the separation speed. Zahn et al. (1973) found a similar influence of this parameter on the shear adhesive strength of Cuvierian tubules in the same species. In their experimental conditions, the shear tenacity of Cuvierian tubules on paraffin wax was about 15 kPa (Zahn et al., 1973), which is four times what we measured on the same substratum with our method (3.7 kPa). This discrepancy could be explained by the fact that, in our experimental design in which a cylindrical structure (the tubule) is compressed and then stretched perpendicular to its long axis, extensive peeling could take place during detachment. In comparison, Zahn et al. (1973) reported that peeling does not occur when Cuvierian tubules are detached in shear (i.e., by pulling along the long axis of the cylinder). It is well known that peeling dramatically reduces adhesion in marine organisms. For example, in the sea anemone Actinia equina, Young et al. (1988) increased the measured normal adhesion strength on Tufnol (a plastic) from 20 kPa to 460 kPa by just switching to an experimental design that reduced the incidence of peel.
The higher tenacities associated with shear loading and preliminary compression of the tubules indicate that Cuvierian tubules are well tailored for functioning as adhesive defense organs. Indeed, in nature, a potential predator entangled in Cuvierian tubules will most likely apply shear loads on the tubules and will therefore experience high adhesion strengths. Moreover, by pulling on the tubules when trying to free itself, it will also maximize their stickiness.
All the factors we tested (i.e., substratum, seawater temperature and salinity, and elapsed time between tubule expulsion and adhesion measurement) had a significant effect on Cuvierian tubule adhesion. Tubules adhered much more strongly to substrata with high surface free energy (glass and stainless steel) than to substrata with low surface free energy (paraffin wax, polyethylene, polystyrene). It is likely the relatively non-polar surfaces of the plastics and the paraffin wax provide a poor surface for interactions with the polar residues of the tubule adhesive (De Moor et al., 2003). All marine bioadhesives characterized thus far are rich in such polar residues (see for example Taylor and Waite, 1997, for mussels; Flammang et al., 1998 for sea stars; Smith et al., 1999, for limpets; or Kamino et al., 2000, for barnacles). They thus show a similar variation of the tenacity on different substrata (see for example Grenon and Walker, 1981, for limpets; Young and Crisp, 1982, for mussels; Yule and Walker, 1987, for barnacles; and Flammang and Walker, 1997, for sea stars).
The temperature and salinity of seawater also influenced the tenacity of holothuroid Cuvierian tubules, adhesion being maximal at the conditions typical of the natural environment of the sea cucumbers. Comparison of the temperate species, H. forskali, to the tropical species, H. leucospilota, shows that each is adapted to its own environment and suggests that the molecular mechanisms of Cuvierian tubule adhesion may be different in the two species. This could explain why tubule adhesive forces in H. forskali (the only temperate species considered in this study) are significantly lower than those in all the tropical species (see above).
In the two investigated species, H. forskali and H. leucospilota, an increase of Cuvierian tubule adhesive strength was observed when adhesion measurements were taken between 1 and 2 hours after tubule expulsion. This is not an adhesion hysteresis effect as the tubules were not attached in the interval between expulsion and measurement. Zahn et al. (1973) demonstrated such a hysteresis effect in H. forskali, but it occurs during test on the order of a few seconds (i.e., a few seconds are required for the maximum adhesive strength of Cuvierian tubules to be achieved). The time scale involved here, as well as the strong influence of temperature on Cuvierian tubule tenacity, suggests an enzymatically-controlled process, in accordance with previous hypotheses on Cuvierian tubule adhesion mechanism based on the influence of various chemical reagents on tubule shear tenacity (Müller et al., 1972; Zahn et al., 1973). These authors suggested that, in H. forskali, a protease-like enzyme may induce the maturation of the protein-based adhesive. However, in our experimental conditions, expelled tubules are not attached to a substratum and it is unlikely that their adhesive, still in the secretory granules of the intact granular cells of the mesothelium, would be chemically modified. This argument also holds true for the experimental design of Müller et al. (1972) and Zahn et al. (1973), in which incubation in chemical reagents was done on elongated, but non-attached, tubules. Molecular events in the inner epithelium and/or in the connective tissue layer are therefore probably responsible for the observed effect of time after expulsion. When the expelled tubules elongate, the inner epithelium is disrupted and the contents of the epithelial cell spherules are released (VandenSpiegel and Jangoux, 1987). Based on morphological evidence, VandenSpiegel and Jangoux (1987) suggested that the spherule contents cover the inner surface of the tubule where they could transform into a cement improving the rigidity of elongated tubules. An increased rigidity of the Cuvierian tubules would presumably reduce peeling effects and therefore increase tenacity. Alternatively, some spherule constituents, including enzymes, could diffuse into the connective tissue layer where they could contribute to the formation of intermolecular cross-links with the same final effect of improving the rigidity of the tubule. Interestingly, Bailey et al. (1982) detected a very high proportion of cross-links in the connective tissue of elongated tubules in H. forskali. After the initial increase, Cuvierian tubule tenacity slowly decreases towards zero after 24 hours, possibly due to denaturation and/or degradation of the tubule constituents.
The adhesive strength of holothuroid Cuvierian tubules, and its variation under different conditions, thus appears to depend not only on the adhesive mechanism taking place at the tubule-substratum interface, but also on the mechanical properties of the tubule inner tissues. Our results stress that it is difficult to distinguish between these two aspects when working with systems as complex as whole tubules, unless integrating the results from other approaches such as morphology and biochemistry.
|
ACKNOWLEDGMENTS |
|---|
We would like to thank Kellar Autumn and Bob Full for inviting us to participate in this symposium. Thanks also to Dr. C. Massin for his help in the identification of the holothuroid specimens, and to P. Postiau for technical assistance. P.F. is a Research Associate of the National Fund for Scientific Research of Belgium (FNRS). This research was supported by the U.S. Office of Naval Research (Grant n° N00014-99-1-0853) and by a FNRS grant to P.F. (n° 1.5181.99—Crédit aux Chercheurs). This study is a contribution of the "Centre Interuniversitaire de Biologie Marine" (CIBIM).
|
FOOTNOTES |
|---|
1 From the Symposium Biomechanics of Adhesion presented at the Annual Meeting of the Society for Integrative and Comparative Biology, 2–6 January 2002, at Anaheim, California.
2 E-mail: Patrick.Flammang{at}umh.ac.be
|
References |
|---|
|
TOP
SYNOPSISINTRODUCTIONMATERIAL AND METHODSRESULTSDISCUSSIONReferences |
|---|
Bailey, A. J., L. J. Gathercole, J. Dlugosz, A. Keller, and C. A. Voyle. 1982. Proposed resolution of the paradox of extensive crosslinking and low tensile strength of Cuvierian tubule collagen from the sea cucumber Holothuria forskali. Int. J. Biol. Macromol, 4:329-334.
De Moor, S., J. H. Waite, M. Jangoux, and P. Flammang. 2002. Characterization of the adhesive from the Cuvierian tubules of the sea cucumber Holothuria forskali (Echinodermata, Holothuroidea). Mar. Biotechnol. (In press).
Endean, R. 1957. The Cuvierian tubules of Holothuria leucospilota. Q. J. Microsc. Sci, 98:455-472.
Flammang, P. 1996. Adhesion in echinoderms. In M. Jangoux and J. M. Lawrence (eds.), Echinoderm studies, Vol. 5, pp. 1–60. Balkema, Rotterdam.
Flammang, P., A. Michel, A. Van Cauwenberge, H. Alexandre, and M. Jangoux. 1998. A study of temporary adhesion of the podia in the sea star Asterias rubens (Echinodermata, Asteroidea) through their footprints. J. Exp. Biol, 201:2383-2395.[Abstract]
Flammang, P., and G. Walker. 1997. Measurement of the adhesion of the podia in the asteroid Asterias rubens (Echinodermata). J. Mar. Biol. Ass. U.K, 77:1251-1254.
Grenon, J.-F., and G. Walker. 1981. The tenacity of the limpet, Patella vulgata L.: An experimental approach. J. Exp. Mar. Biol. Ecol, 54:277-308.[CrossRef]
Guislain, R. 1953. Recherches histochimiques sur les canaux de Cuvier de Holothuria impatiens Forskal. C. R. Soc. Biol. Paris, 147:1254-1256.
Hamel, J.-F., and A. Mercier. 2000. Cuvierian tubules in tropical holothurians: Usefulness and efficiency as a defence mechanism. Mar. Fresh. Behav. Physiol, 33:115-139.
Kamino, K., K. Inoue, T. Maruyama, N. Takamatsu, S. Harayama, and Y. Shizuri. 2000. Barnacle cement proteins. Importance of disulfide bonds in their insolubility. J. Biol. Chem, 275:27360-27365.
Lawrence, J. M. 2001. Function of eponymous structures in echinoderms: A review. Can. J. Zool, 79:1251-1264.[CrossRef]
Müller, W. E. G., R. K. Zahn, and K. Schmid. 1972. The adhesive behaviour in Cuvierian tubules of Holothuria forskali. Biochemical and biophysical investigations. Cytobiologie, 5:335-351.
Smiley, S. 1994. Holothuroidea. In F. W. Harrison and F.-S. Chia (eds.), Microscopic anatomy of invertebrates, Vol. 14, Echinodermata, pp. 401–471. Wiley-Liss, New York.
Smith, A. B., T. J. Quick, and R. L. St. Peter. 1999. Differences in the composition of adhesive and non-adhesive mucus from the limpet Lottia limatula. Biol. Bull, 196:34-44.[Abstract]
Taylor, S. W., and J. H. Waite. 1997. Marine adhesives: From molecular dissection to application. In K. McGrath and D. Kaplan (eds.), Protein-based materials, pp. 217–248. Birkhäuser, Boston.
VandenSpiegel, D., and M. Jangoux. 1987. Cuvierian tubules of the holothuroid Holothuria forskali (Echinodermata): A morphofunctional study. Mar. Biol, 96:263-275.
VandenSpiegel, D., and M. Jangoux. 1993. Fine structure and behaviour of the so-called Cuvierian organs on the holothuroid genus Actinopyga (Echinodermata). Acta Zool. (Stockh.), 74:43-50.
VandenSpiegel, D., M. Jangoux, and P. Flammang. 2000. Maintaining the line of defense: Regeneration of Cuvierian tubules in the holothuroid Holothuria forskali (Echinodermata). Biol. Bull, 198:34-49.[Abstract]
Walker, G. 1987. Marine organisms and their adhesion. In W. C. Wake (ed.), Synthetic adhesives and sealants, pp. 112–135. John Wiley & Sons, Chichester.
Young, G. A., and D. J. Crisp. 1982. Marine animals and adhesion. In K. W. Allen (ed.), Adhesion, Vol. 6, pp. 19–39. Applied Sciences, London.
Young, G. A., A. B. Yule, and G. Walker. 1988. Adhesion in the sea anemones Actinia equina L. and Metridium senile (L). Biofouling, 1:137-146.
Yule, A. B., and G. Walker. 1987. Adhesion in barnacles. In A. J. Southward (ed.), Crustacean issues, Vol. 5, Biology of barnacles, pp. 389–402. Balkema, Rotterdam.
Zahn, R. K., W. E. G. Müller, and M. Michaelis. 1973. Sticking mechanisms in adhesive organs from a Holothuria. Res. Mol. Biol, 2:47-88.
Zar, J. H. 1984. Biostatistical analysis. Prentice Hall, Engelwood Cliffs, New Jersey.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  J. H. Waite Adhesion a la Moule Integr. Comp. Biol., December 1, 2002; 42(6): 1172 - 1180. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||