Chemistry of Hydra Nematocysts1

Weber, Jakob; Klug, Marianne; Tardent, P.

doi:10.1016/b978-0-12-345320-4.50027-4

Cited by 14 publications

(15 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the works of Robson [18], Carre [17], Lubbock and coworkers [9, 341 and from our own laboratory [6,27,351, it has become evident that at least in some, and possibly in most if not all, nematocysts, internal pressure as well as intrinsic tension forces jointly contribute to this process. We present here the first report that demonstrates unequivocally the osmotic nature of the internal pressure in nematocysts, measures this high osmotic pressure, and which, in addition, offers insight into its regulation, thus allowing predictions and extrapolations concerning possible discharge mechanisms.…”

Section: Discussionmentioning

confidence: 99%

“…Purified nematocysts were isolated from whole hydra polyps by a Percoll centrifugation procedure described elsewhere [20]. In order to obtain an optimal purification, care was taken to resuspend the neinatocysts completely during all the washings.…”

Section: Methodsmentioning

confidence: 99%

“…This phenomenon, which is observed in intact nematocysts [27], was used to estimate relative affinities of different cations for the polyanionic capsular content (cf. Appendix).…”

Section: Apparent Affinities Of Nematocysts F O R Various Cationsmentioning

confidence: 99%

“…Isolated nematocysts (capsules of stinging cells in Cnidaria) from the freshwater polyp Hydra vulgaris [Weber, J., Klug, M. & Tardent, P. (1987) Comp. Biochem.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Nematocysts (stinging capsules of Cnidaria) as Donnan‐potential‐dominated osmotic systems

Weber

1989

European Journal of Biochemistry

Self Cite

View full text Add to dashboard Cite

Isolated nematocysts (capsules of stinging cells in Cnidaria) from the freshwater polyp Hydra vulgaris [Weber, J., Klug, M. & Tardent, P. (1987) Comp. Biochem. Physiol. 883, 855-8621 are under a constant internal osmotic pressure of 12.5 MPa. The capsular wall which withstands this considerable pressure has an average elasticity modulus of approximately 1 GPa, enabling the cyst to swell from its relaxed state to more than double its volume. If the large concentrations of Mg2+ and Ca2+ within isolated nematocysts are substituted by alkali ions, the ppsular volume increases by 15% and the final osmotic pressure rises to 15.3 MPa whereas after substitution by Ca2+ a decrease to 90% of the volume and 6.5 MPa is observed.Evidence obtained from the osmotic behavior of nematocysts, as well as data from in vitro exchange of their cations, are consistent with a physicochemical model in which the internal osmotic pressure of nematocysts and thus their ability to discharge is governed by the cationic composition of the content and the salt concentrations in the environment.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…This phenomenon, which is observed in intact nematocysts [27], was used to estimate relative affinities of different cations for the polyanionic capsular content (cf. Appendix).…”

Section: Apparent Affinities Of Nematocysts F O R Various Cationsmentioning

confidence: 99%

“…Isolated nematocysts (capsules of stinging cells in Cnidaria) from the freshwater polyp Hydra vulgaris [Weber, J., Klug, M. & Tardent, P. (1987) Comp. Biochem.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Nematocysts (stinging capsules of Cnidaria) as Donnan‐potential‐dominated osmotic systems

Weber

1989

European Journal of Biochemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…It has been reported that the process of lyophilization does not alter the structure of cnidocysts, thus allowing for their preservation over long periods of time (Weber et al 1988;Bloom et al 1998). This has also been shown for cnidocysts isolated from the lyophilized tentacles of B. an- nulata, where p-microbasic mastigophores and spirocysts are easily discharged in distilled water after having been lyophilized and frozen for one year.…”

Section: Discussionmentioning

confidence: 99%

Isolation, Partial Purification and Characterization of Active Polypeptide from the Sea Anemone Bartholomea annulata

Sánchez‐Rodríguez¹,

Zugasti²,

Santamarı́a³

et al. 2006

Basic Clin Pharma Tox

View full text Add to dashboard Cite

In the sea anemone Bartholomea annulata, four different types of cnidocysts, basitrichous isorhizas, microbasic p-mastigophores, microbasic amastigophores and spirocysts were identified. In relation to the efficacy of different substances to induce discharge of nematocysts we observe that distilled water induced more than 70% of microbasic pmastigophores to discharge, whereas spirocysts were discharged in a lesser extent (∑20%). The median lethal dose (LD 50 ) in mice was found after injection of 700.7 mg protein per kg of body weight from the crude extract. The protein with neurotoxic effect was isolated using low-pressure liquid chromatography. The neurotoxic activity was determined using sea crabs (Ocypode quadrata), injecting 15 mg of crude extract or isolated fraction into the third walking leg, and violent motor activity followed by progressive loss of sensibility to external stimuli, further leading to full paralysis were observed. The active fraction (called V) eluted at 43.9 min.Sea anemones as well as corals, hydrozoans, scyphozoans and cubozoans, are included in the Phylum Cnidaria, the only group in the animal kingdom with the ability to produce cnidocysts. Cnidocysts are among the largest and most complex intracellular secretion products known (Holstein & Tardent 1984). There are 28 types of morphologically distinct cnidocysts, which are divided into three subcategories: nematocysts (25 different types), spirocysts (2 types), and one type of ptychocysts (Mariscal 1974). From these three subcategories, only nematocysts inject toxins into prey, and thus they are considered as the most sophisticated lethal weapons in the animal kingdom (Tardent 1995).Nematocysts from sea anemones contain complex mixtures of biologically active compounds, mainly consisting of peptides and proteins (Béress 1982;Hessinger 1988;Kem 1988;Norton 1991). Although the first toxins isolated from these cnidarians were neurotoxins (Béress & Béress 1974), cardiotoxins (Simpson et al. 1990), and several cytolysins (Kem 1988), protease inhibitors have also been found (Delfín et al. 1996). Indeed, although some anemone toxins have been extensively investigated during recent years, information regarding the biological activity of many of them is scarce. In the particular case of Bartholomea annulata, the only report in the literature is the study by Santamaría et al. (2002). In this study, the authors evaluated the haemolytic and peroxidative responses by the crude extract in mice erythrocytes. In consideration of the information mentioned above, the aim of this work is to evaluate the biotoxic parameters of both the crude extract and the partially purified venom from B. annulata in different experimental models. Materials and MethodsIn order to identify the different types of cnidocysts present in tentacles of B. annulata, preparations were preserved with 4% formaldehyde, glycerine and 96% ethyl alcohol, and analyzed by light microscopy (20¿, 40¿ and 100¿). Cnidocysts from both fresh and frozen specimens were also observed i...

show abstract

Intracellular calcium transients during nematocyst discharge in actinulae of the hydroid,Tubularia mesembryanthemum

Kawaii¹,

Yamashita²,

Nakai³

et al. 1997

J. Exp. Zool.

View full text Add to dashboard Cite

The discharge of atrichous isorhiza (AI) from the aboral tentacle tips (ATT) is an integral process during settlement of actinula larvae of the marine hydroid Tubularia mesembryanthemum, since discharged adhesive tubules from AI anchor actinula to settlement substrata. Under experimental conditions, AI discharge was triggered either by contact with bacterial film‐coated micropipettes or by exposure to artificial seawater (ASW) containing high concentrations of K+ ions (K+‐ASW). Triggering of AI discharge required both contact by ATT with the substrata and the presence of Ca2+ions in the bathing solution. Changes in intracellular Ca2+ion concentration ([Ca2+]i) were monitored by measuring fluorescence images obtained from ATT of intact actinulae loaded with fura‐2. An initial low [Ca2+]i(R340/380=1.0) value was rapidly elevated by K+‐ASW treatment (R340/380=1.9) and simultaneously accompanied by AI discharge. These results suggest that Ca2+ions present in the bathing solution flow into nematocytes during the AI discharge process. J. Exp. Zool. 278:299–307, 1997. © 1997 Wiley‐Liss, Inc.

show abstract

Chemistry of Hydra Nematocysts1

Cited by 14 publications

References 27 publications

Nematocysts (stinging capsules of Cnidaria) as Donnan‐potential‐dominated osmotic systems

Nematocysts (stinging capsules of Cnidaria) as Donnan‐potential‐dominated osmotic systems

Isolation, Partial Purification and Characterization of Active Polypeptide from the Sea Anemone Bartholomea annulata

Intracellular calcium transients during nematocyst discharge in actinulae of the hydroid,Tubularia mesembryanthemum

Contact Info

Product

Resources

About