Chemistry of coelenterates. VI. Occurrence of gorgosterol, a C30 sterol, in coelenterates and their zooxanthellae.
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Chemical nature of bioluminescence systems in coelenterates.
Analysis of substances involved in light-emitting reactions among bioluminescent coelenterates has revealed a pronounced uniformity in the structural features of initial reactants, i.e., "luciferins" and photo-protein chromophores, as well as the light-emitter product. This product is structurally identical among the different classes of coelenterates: Hydrozoa (the jellyfish, Aequorea), Anthozoa (the sea cactus, Cavernularia; sea pansy, Renilla; and sea pen, Leioptilus), and very likely also the Scyphozoa (the jellyfish, Pelagia). In each of these instances the reaction product, namely, 2-(p-hydroxy-pnenylacetyl)amino-3-benzyl-5-(p-hydroxyphenyl) pyrazine, is the actual light-emitter, whether it occurs in a Ca2+-triggered photoprotein type of luminescence, or in a "luciferin-luciferase" type. The evidence indicates that in certain coelenterates, e.g., Cavernularia, these two types are equally significant, whereas in others (Renilla and Leioptilus) the "luciferin-luciferase" type predominates over the Ca-triggerable photoprotein type, and finally that only the photoprotein type functions in the luciferaseless jellyfish, Aequorea. In all instances investigated, the structure of the light-emitter prior to the luminescence reaction appears to be essentially the same as that of the chromophore of unreacted aequorin. The product of the luminescence reaction is absent in extracts of non luminous species. However, a product very similar to that of luminescent coelenterates occurs also in representatives of other phyla, including the cephalopod molluscs, e.g., the "firefly squid" Watasenia and probably various ctenophores as well.
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Identification, isolation and characterization of tetracosapolyenoic acids in lipids of marine coelenterates.
Several tetracosapolyenoic acids (TPA) were detected in lipids of different marine coelenterates. Two of these acids were isolated and their structures were confirmed by chemical and spectral methods as all-cis-6,9,12,15,18-tetracosapentaenoic and all-cis-6,9,12,15,18,21-tetracosahexaenoic acid. Their distribution among lipids of a number of species of different classes of coelenterates from the northern and tropical seas, among neutral and polar lipids of these organisms was investigated. Significant quantities of TPA were found in all of the Octacorallia species studied. In some cases the sum of TPA reaches the level of 20% of total lipid fatty acids. The fatty acid composition of different coelenterates is also discussed.
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Arg-Phe-amide-like peptides in the primitive nervous systems of coelenterates.
By using immunocytochemistry and radioimmunoassays, several substances resembling vertebrate or invertebrate neuropeptides have been found in the nervous systems of coelenterates. The most abundant neuropeptides were those related to the molluscan neuropeptide Phe-Met-Arg-Phe-amide (FMRFamide). Of antisera against different fragments of FMRFamide, those against RFamide were superior in recognizing the coelenterate peptide. Incubation of whole mounts with these RFamide antisera visualized the coelenterate nervous system in such a detail as has previously not been possible. By using a radioimmunoassay with a RFamide antiserum and [J-125]-YFMRFamide as tracer, the RFamide-like peptide from sea anemones was isolated. After cation-exchange chromatography, gelfiltration and HPLC, this peptide was obtained in a pure form.
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Recurrent eruptions following unusual solitary coelenterate envenomations.
The case history of four patients is presented. The first patient exhibited normal immunologic reactions to large artificial intradermal challenge with jellyfish venom and later, multiple small natural stings. The second patient, presumably envenomated by a jellyfish, had four recurrent cutaneous eruptions in a linear configuration at the same anatomic site. Because her primary coelenterate contact occurred at a time when she was receiving systemic corticosteroids, it is assumed that the eruption due to the initial sting was delayed. The third and fourth patients exhibited recurrent eruptions after solitary envenomations by different coelenterates. These case histories demonstrate that multiple recurrent eruptions may follow solitary envenomations by different subphyla of coelenterates, that the initial eruption induced by the sting may be delayed by the administration of high doses of systemic corticosteroids, and that an immunologic reaction in both the B and T cell systems can follow jellyfish envenomation.
Adult↗
Neurones and neuropeptides in coelenterates.
The first nervous system probably evolved in coelenterates. Many neurons in coelenterates have morphological characteristics of both sensory and motor neurones, and appear to be multifunctional. Using immunocytochemistry with antisera to the sequence Arg-Phe-NH2 (RFamide), RFamide-like peptides were demonstrated in the nervous systems of all classes of coelenterates. Using a radioimmunoassay for RFamide, three such peptides were isolated from the sea anemone Anthopleura elegantissisma and sequenced: less than Glu-Gly-Arg-Phe-NH2 (Antho-RFamide), less than Glu-Ser-Leu-Arg-Trp-NH2 (Antho-RWamide I) and less than Glu-Gly-Leu-Arg-Trp-NH2 (Antho-RWamide II). The general structure of these peptides can be described as less than Glu...Arg-X-NH2, where X is an aromatic amino acid. From the hydromedusa Polyorchis penicillatus, the peptide less than Glu-Leu-Leu-Gly-Gly-Arg-Phe-NH2 (Pol-RFamide I) was isolated, which also belongs to the less than Glu...Arg-X-NH2 family. Using specific antisera it was shown that all four peptides were located in neurones. Application of low doses of Antho-RFamide, or Antho-RWamide I or II induced contractions of endodermal muscles of sea anemones. This indicates that these neuropeptides play a role in neurotransmission.
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Glutamate dehydrogenase from coelenterates is NADP specific.
Glutamate dehydrogenases detected in tissue extracts of a broad sample of coelenterate species all require NADP(H) as a co-substrate, rather than being capable of using either NAD(H) or NADP(H). In this respect, the coelenterate phyla appear to be unique in the animal kingdom.
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The molecular basis of the self/nonself selectivity of a coelenterate toxin.
Coelenterates produce potent hemolysins inhibited by sphingomyelin (SM). Remarkably, instead of this lipid, their membranes contain a phosphono analogue of it. Using coelenterolysin (CL), a toxin produced by the sea anemone Phymactis clematis, we have examined a possible connection between these two peculiar traits. Our experiments showed that, while SM binds this lysin and inhibits its hemolytic activity, the endogenous PnSL do neither. In addition, liposomes made of bovine erythrocyte lipids are rapidly disrupted by CL, while those made of P. clematis lipids are completely resistant to it. However, if small amounts of SM are added to the P. clematis lipids, the resulting liposomes become sensitive to CL. Taken together, our results show for the first time that substitution of SM by its phosphono analogue is the molecular basis for the selectivity of an anthozoan toxin. We therefore propose that exotoxin production and membrane composition are coadapted traits that confer on the coelenterates a significant evolutionary advantage.
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Ultrastructure of nematocytes and one-celled tentacles of the freshwater coelenterate, Calpasoma dactyloptera.
Calpasoma dactyloptera, a tentacled form of minute, freshwater coelenterate, has been investigated by light and electron microscopy and time-lapse cinematography. Each tentacle consists of a protrusion from a single ectodermal epithelial cell termed a tentaculocyte. Thus, unlike most coelenterate tentacles, neither mesoglea nor endoderm is present in the tentacle. Large numbers of nematocytes are present, however. When the nematocytes are poised, they sit within tentaculocyte vesicles which represent invaginations of the plasma membrane. A cnidocil protrudes into the external medium. The bottom of each nematocyte is elongated as a stalk which extends to the tentacle base, coursing through tubular membrane lined channels within the tentaculocyte. A network of fibers and microtubules, originating in the cnidocil, extends to the base of the nematocyte stalk.
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Gastrin/CCK-like immunoreactivity in the nervous system of coelenterates.
Using immunocytochemistry, gastrin/CCK-like immunoreactivity is found in sensory nerve cells in the ectoderm of the mouth region of hydra and in nerve cells in the endoderm of all body regions of the sea anemone tealia. These results are corroborated by radioimmunoassay: One hydra contains at least 5 fmole and one tealia at least 2 nmole gastrin/CCK-like immunoreactivity. Reactivities towards gastrin and CCK antisera with different specificities suggest that the coelenterate gastrin/CCK-like peptide contains the C-terminal amino-acid sequence common to mammalian gastrin and CCK. In addition the radioimmunochemical data indicate that the coelenterate peptide also contains an amino-acid sequence that resembles the sequence 20-30 of porcine CCK-33, but that no other sequences of gastrin are present. Thus, it is probably more CCK-like than gastrin-like.
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Histologic study of delayed reactions to coelenterates.
We studied by immunohistochemistry three cases of delayed envenomation by coelenterates. The most prominent features were the grouping of human leukocyte antigen-DR-positive cells with Langerhans cells (S-100 positive) and helper/inducer T lymphocytes (Leu-1+, Leu-3+, and Leu-4+). This indicates the possibility of a type IV immunoreaction in the delayed cutaneous lesions caused by coelenterates.
Adult↗
Properties of a catecholaminergic system in some coelenterates. A histochemical and autoradiographic study.
Properties of a catecholaminergic nervous system in a coelenterate nervous system are described. The catecholamine present shows similarities to noradrenalin but it is not identical with noradrenalin. Contrary to known vertebrate catecholaminergic systems, neither a reuptake system nor a degrading system is present in the coelenterate catecholaminergic nervous system.
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Delayed and persistent cutaneous reactions to coelenterates.
Three patients are described who developed firm, persistent papules and plaques at sites of previous contact with two species of coelenterates. Histologically, a predominantly mononuclear inflammatory cell infiltrate located primarily in the reticular dermis was observed with destruction of hair follicle epithelium and arrectores pilorum. Epidermal changes included focal spongiosis and exocytosis of lymphocytes. The eruptions subsided no sooner than 7 weeks from time of onset. It is hypothesized that this cutaneous reaction represents a persistent delayed hypersensitivity response to an antigenic component of the coelenterate nematocyst.
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Acute reactions to coelenterates.
Many coelenterates can injure human skin by means of their nematocytes. Our study was based upon clinico-pathological confrontations and was also conducted in vitro with sea anemones. Most acute reactions were toxic in nature and induced sublethal and lethal alterations of the keratinocytes with swelling of their cytoplasms and pyknosis. Another reaction found in 1 patient revealed an acantholytic disruption of the epidermis associated with intercellular deposits of IgG. These lesions were different from the late or recurrent reactions to coelenterates.
Acute Disease↗
Capacity for biosynthesis of prostaglandin-related compounds: distribution and properties of the rate-limiting enzyme in hydrocorals, gorgoniants, and other coelenterates of the Caribbean and Pacific.
A convenient and reliable assay is described for PGEP synthetase, the rate-limiting enzyme determining the total capacity for biosynthesis of prostaglandin-related compounds. Results of such assays, performed withe fresh specimens under both field and laboratory conditions, newly identify several marine coelenterate species as potentially important resources of PGRCs for research and possible development. Properties of the typical marine coelenterate PGEP synthetase, and the reaction which this enzyme catalyzes, have been further characterized.
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Suspected chemoreceptors in coelenterates and ctenophores.
Chemoreceptors in coelenterates and ctenophores have not been identified with certainty. Among prospective chemoreceptive cells are the sensory nerve cells, the cnidocyst-bearing cnidocytes, and the epitheliomuscular cells that are likely to be involved in feeding or aggression. Both behaviors are mediated by coordinated chemical and mechanical reception. This is reflected in the close apposition of putative chemo- and mechanoreceptors. Among the structures that have been designated as likely chemo- and/or mechanoreceptors are stereocilia, kinocilia, and/or microvilli which are universally present on all the putative chemoreceptor complexes, while gland cells and mucous secretions are prevalent. Evidence that the actin-containing stereocilia are chemically modulated mechanoreceptors is presented for several forms.
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Lymphokine activity in coelenterate envenomation.
Four patients were tested to determine whether lymphokine activity could be produced by their peripheral blood leukocytes exposed to jellyfish antigens. One patient was a false positive reactor, one had a prolonged lymphokine response three years after a persistent eruption induced by the venom, and one had lymphokine activity associated only with the cutaneous eruption. These results support the hypothesis that T cell function may be important in the pathogenesis of cutaneous lesions following coelenterate envenomation.
Bites and Stings↗
Venomous pelagic coelenterates: chemistry, toxicology, immunology and treatment of their stings.
Ten years have elapsed since our last review article on the toxicology of venomous pelagic coelenterates was published (Burnett and Calton, 1977). Investigation on important medusae and the chemistry of their nematocyst venoms have been expanding. The venomous jellyfish discussed here include the Portuguese man-o'war, (Physalia physalis), the sea nettle (Chrysaora quinquecirrha), the box jellyfish (Chironex fleckeri and/or Chiropsalmus quadrigatus), the cabbage head jellyfish (Stomolophus meleagris), the lion's mane jellyfish (Cyanea capillata), the Irukandji jellyfish (Carukia barnesi), the Moreton Bay Carybdeid medusa (Morbakka), and the mauve blubber (Pelagia noctiluca).
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