Evaluation of the effects of various chemicals on discharge of and pain caused by jellyfish nematocysts

Jellyfish tentacles in contact with human skin can produce pain swelling and redness. The pain is due to discharge of jellyfish nematocysts and associated toxins and discharge can be caused by a variety of mechanical and chemical stimuli. A series of tests were carried out with chemicals traditionally used to treat jellyfish stings e.g. acetic acid ammonia meat tenderizer baking soda and urea to determine if these chemicals stimulated or inhibited nematocyst discharge and if they brought relief to testers who were exposed to jellyfish tentacles. Chrysaora quinquecirrha (sea nettle) Chiropsalmus quadrumanus (sea wasp) and Physalia physalis (Portuguese man-of-war) were used in the study. It was found that many of the chemicals traditionally used to treat jellyfish stings stimulated nematocyst discharge and did not relieve the pain. However there was immediate relief when a common anesthetic lidocaine was sprayed on the skin of testers in contact with jellyfish tentacles. Initial exposure of tentacle suspensions to lidocaine prevented the nematocyst discharge by subsequent exposure to acetic acid ethanol ammonia or bromelain. Thus lidocaine in addition to acting as an anesthetic on skin in contact with jellyfish tentacles inhibited nematocyst discharge possibly by blocking sodium and/or calcium channels of the nematocytes.     

Endobacteria in the tentacles of selected cnidarian species and in the cerata of their nudibranch predators

This is the first genetic analysis comparing cultured endobacteria discovered in the tentacles of cnidarian species (Tubularia indivisa, Tubularia larynx, Corymorpha nutans, Sagartia elegans) with those found in the cerata tips of selected nudibranch species (Berghia caerulescens, Coryphella lineata, Coryphella gracilis, Janolus cristatus, Polycera faeroensis, Polycera quadrilineata, Doto coronata, Dendronotus frondosus). Shared pathogenic activities were found among other microorganisms in the Pseudoalteromonas tetraodonis group (TTX), and the Vibrio splendidus group (haemolytic, septicaemic, necrotic activity). Specific autochthonous endobacteria of extremely low similarity to their next neighbours were detected in nudibranch cerata. These organisms are regarded as new and unknown endobacteria; among them were Pseudoalteromonas luteoviolacea (95%), Orientia tsutsugamushi (84%), Gracilimonas tropica (96%), Balneola alkaliphia (95%), Loktanella rosea (97%). SEM micrographs provide insight into endobacterial aggregates in cnidarian tentacles and nudibranch cerata. Since certain nudibranch predators prey on cnidarian species, it is assumed that cnidarian tentacle bacteria are directly transferred to nudibranch cerata. The pathogenic endobacteria may contribute to the chemical defence of both the nudibranch and cnidarian species investigated.     

Endobacterial morphotypes in nudibranch cerata tips: a SEM analysis

The SEM investigation of nudibranch cerata material exhibits endobacterial morphotypes found in 12 out of 13 species tested: Aeolidia papillosa, Berghia caerulescens, Coryphella brownii, Coryphella lineata, Coryphella verrucosa, Cuthona amoena, Facelina coronata, Flabellina pedata, Dendronotus frondosus, Doto coronata, Tritonia plebeia and Janolus cristatus. Endobacteria could not be detected inside Tritonia hombergi. Endobacterial morphology found inside nudibranch species was compared to bacterial morphotypes detected earlier in tentacles of cnidarian species. SEM micrographs show endobacterial analogy among nudibranch species, but also similarity to cnidarian endobacteria investigated earlier. Of course, morphological data of microbes do not allow their identification. However, since most of these nudibranch species prey on cnidaria, it cannot be excluded that many of the endobacteria detected inside nudibranch species may originate from their cnidarian prey. Our previous data describing genetic affiliation of endobacteria from nudibranchian and cnidarian species support this assumption. Dominant coccoid endobacteria mostly exhibit smooth surface and are tightly packed as aggregates and/or wrapped in envelopes. Such bacterial aggregate type has been described previously in tentacles of the cnidarian species Sagartia elegans. Similar coccoid bacteria, lacking envelopes were also found in other nudibranch species. A different type of coccoid bacteria, characterized by a rough surface, was detected inside cerata of the nudibranch species Berghia caerulescens, and surprisingly, inside tentacles of the cnidarian species Tubularia indivisa. In contrast to cnidarian endobacteria, rod-shaped microorganisms are largely absent in nudibranch cerata.     

First in situ observations of the deep-sea squid Grimalditeuthis bonplandi reveal unique use of tentacles

The deep-sea squid Grimalditeuthis bonplandi has tentacles unique among known squids. The elastic stalk is extremely thin and fragile, whereas the clubs bear no suckers, hooks or photophores. It is unknown whether and how these tentacles are used in prey capture and handling. We present, to our knowledge, the first in situ observations of this species obtained by remotely operated vehicles (ROVs) in the Atlantic and North Pacific. Unexpectedly, G. bonplandi is unable to rapidly extend and retract the tentacle stalk as do other squids, but instead manoeuvres the tentacles by undulation and flapping of the clubs’ trabecular protective membranes. These tentacle club movements superficially resemble the movements of small marine organisms and suggest the possibility that G. bonplandi uses aggressive mimicry by the tentacle clubs to lure prey, which we find to consist of crustaceans and cephalopods. In the darkness of the meso- and bathypelagic zones the flapping and undulatory movements of the tentacle may: (i) stimulate bioluminescence in the surrounding water, (ii) create low-frequency vibrations and/or (iii) produce a hydrodynamic wake. Potential prey of G. bonplandi may be attracted to one or more of these as signals. This singular use of the tentacle adds to the diverse foraging and feeding strategies known in deep-sea cephalopods.     

Comparative ultrastructure of catch tentacles and feeding tentacles in the sea anemone Haliplanella

TEM observations of catch tentacles revealed that the tentacle tip epidermis is filled with two size classes of mature holotrich nematocysts and a gland cell filled with electron-dense vesicles. Vesicle production is restricted to upper-middle and tentacle tip regions, whereas holotrich development occurs in the lower-middle and tentacle base regions. Thus, catch tentacles have a maturity gradient along their length, with mature tissues concentrated at the tentacle tip. Occasional feeding tentacle cnidae (microbasic p-mastigophores and basitrichs) and mucus gland cells occur in proximal portions of catch tentacles, but are phagocytized by amoeboid granulocytes and transported to the gastrodermis for further degradation. No feeding tentacle cnidae or mucus cells occur distally in catch tentacles. Unlike catch tentacles, feeding tentacles are homogeneous in structure along their length with enidocytes containing mature spirocysts, microbasic p-mastigophore or basitrich nematocysts distributed along the epithelial surface. Cnidoblasts are recessed beneath cnidocytes, occurring along the nerve plexus. Mucus gland cells and gland cells filled with electron-dense vesicles are present in feeding tentacles, distributed at the epithelial surface. Granular phagocytes are rare in the feeding tentacle tip, but common in the tentacle base.     

Ontogeny of the fused tentacles in three species of ommastrephid squids (Cephalopoda, Ommastrephidae)

Abstract. The tentacles of ommastrephid squids fuse during embryonic development and remain fused as they grow through hatching, but eventually separate to become two fully functional adult tentacles. The external anatomy of individuals at several post‐hatching ontogenetic stages of three species of ommastrephid squids (Ommastrephes bartramii, Sthenoteuthis oualaniensis, and Hyaloteuthis pelagica) was examined using scanning electron microscopy and morphometrics. The fusion of the transverse muscle mass of the tentacles was examined using light microscopy. Five ontogenetic stages of tentacle separation were defined based on landmark features such as the extent of the fusion and the presence of suckers or sucker buds at the distal tip. The total tentacle length and fused tentacle length reached a maximum when the dorsal mantle length (ML) equaled 3–4 mm (H. pelagica) or 4–6 mm (O. bartramii, S. oualaniensis), and then decreased with increasing ML. The average split length (measured from the base of the tentacles to the point of tentacle fusion) increased gradually with increasing ML, and the separate tentacle diameter was roughly half the diameter of the fused portion at all sizes. In all three species, separation of the fused tentacles began earlier in development (2–3‐mm ML) and was more advanced at smaller sizes than previously reported. The sizes presented here are conservative because excess epithelium at the location of the split may disguise the actual site of separation. Post‐separation tentacles were much shorter than the arms, and the carpal region appeared torn in 2 of the 4 specimens of S. oualaniensis examined. Finally, none of the original distal tip suckers were retained on the post‐separation tentacles of S. oualaniensis. These observations are consistent with the hypothesis that the tentacles separate gradually then rupture at the “wrist” (presumptive carpus), and argue against the possibility of prey capture by the fused tentacles.     

The fine structure and function of the tentacle in Tokophrya infusionum

The feeding apparatus of Suctoria consists of long, thin, stiff tubes called tentacles. When a swimming prey attaches to the tip of the tentacle a number of events follow in rapid succession. The tentacle broadens, a stream of tiny granules starts to move upward at its periphery to the tip, the prey becomes immobilized and shortly thereafter the cytoplasm of the still living prey begins to flow through the center of the tentacle to the body of the predator. An electron microscope study of the tentacle in Tokophrya infusionum, a protozoan of the subclass Suctoria, has disclosed a number of structural details which help to clarify some of the mechanisms involved in this unusual way of feeding. Each tentacle is composed of two concentric tubes. The lumen of the inner tube is surrounded by 49 tubular fibrils most probably of contractile nature. In the inner tube the cytoplasm of the prey is present during feeding, and in the outer tube are small dense bodies. It was found that the dense bodies originate in the cytoplasm of Tokophrya. They have an elongate, missile-like appearance, pointed at one end, rounded at the other, and are composed of several distinct segments. At the tip of the tentacle they penetrate the plasma membrane, with their pointed ends sticking out. It is assumed that the missile-like bodies play a major role in the feeding process. Their composite structure suggests that they might contain a number of enzymes which most probably are responsible for the various events preceding the actual food intake.     

Cryptic diets of forage fish: jellyfish consumption observed in the Celtic Sea and western English Channel

To establish if fishes’ consumption of jellyfish changes through the year, we conducted a molecular gut-content assessment on opportunistically sampled species from the Celtic Sea in October and compared these with samples previously collected in February and March from the Irish Sea. Mackerel Scomber scombrus were found to feed on hydrozoan jellyfish relatively frequently in autumn, with rare consumption also detected in sardine Sardina pilchardus and sprat Sprattus sprattus. By October, moon jellyfish Aurelia aurita appeared to have escaped predation, potentially through somatic growth and the development of stinging tentacles. This is in contrast with sampling in February and March where A. aurita ephyrae were heavily preyed upon. No significant change in predation rate was observed in S. sprattus, but jellyfish predation by S. scombrus feeding in autumn was significantly higher than that seen during winter. This increase in consumption appears to be driven by the consumption of different, smaller jellyfish species than were targeted during the winter.     

Size and shape in the phylum Phoronida

The lophophorate phylum Phoronida consists of about 13 species, which differ in body length and width, number of longitudinal muscles, lophophore geometry and number of lophophore tentacles. In absolute terms large species have a larger body width, more tentacles, more longitudinal muscles and greater coiling of the lophophore than small species. However, size and shape analyses suggest that with increasing size: (I) the body surface area to volume ratio increases because body length increases faster than body width; (2) the relative number longitudinal muscles decreases, and (3) the relative feeding surface area of the lophophore decreases because tentacle diameter is constant while tentacle number increases at the same rate as body length and tentacle length increases more slowly than tentacle number. Coiling and spiraling of the lophophore in large species may be an attempt to compensate for this last relationship. We suggest that the habits, mode of growth and feeding mechanism of phoronids constrain size-related changes in shape.     

MICROTUBULE ARMS AND CYTOPLASMIC STREAMING AND MICROTUBULE BENDING AND STRETCHING OF INTERTUBULE LINKS IN THE FEEDING TENTACLE OF THE SUCTORIAN CILIATE TOKOPHRYA

Microtubules attached to the pellicle at the tips of tentacles pivot through about 140° on these attachments, splay apart, and bend along their longitudinal axes when feeding occurs. The tubules could be bending in response to pellicular contractions; active bending, sliding, or contraction of the tubules may not be involved. Intertubule links apparently prevent tubules from splaying apart at certain levels. These links are probably under tension during feeding. They stretch; they sometimes become half as thick and eight times as long as they are before feeding. Often, tubules joined together by these links also change in shape; they become slightly flattened and elliptical in cross section. Cytoplasm from the ciliate Tetrahymena is drawn down a feeding tentacle inside an invagination of the Tokophrya cell membrane from the tentacle tip. The positions of arm-bearing microtubules around such invaginations indicate that arms are involved in moving invaginations along. The edges of the perforated Tetrahymena cell membrane are "sealed" to the cell membrane of Tokophrya around each feeding tentacle tip.     

Predation by the phyllosoma larva of Ibacus novemdentatus on various kinds of venomous jellyfish

The phyllosoma, a larva of spiny and slipper lobsters, has an exceptionally flat body and long appendages. It is known to associate with several species of cnidarian jellyfish, a behavior that is not rare in crustaceans. Indeed, phyllosomas clinging onto jellyfish have been observed both in the laboratory and in the natural environment. Wild phyllosomas have been found to contain jellyfish tissues in their hepatopancreas and feces, suggesting that the larvae utilize jellyfish as a food source; however, how they capture jellyfish and what species of jellyfish they prefer have rarely been investigated. The few previous studies conducted have suggested that phyllosomas have a high specificity for jellyfish (preying on only a few species); in contrast, the results of our study indicate that specificity is low. We show that phyllosomas prey on a variety of jellyfish species including deadly stinging types, on a variety of jellyfish developmental stages, and on various parts of the jellyfish body. When making contact with a jellyfish, phyllosomas first cling onto its exumbrella, feed on its tentacles or oral arms, and then consume the exumbrella. Phyllosomas may be capable of defending themselves against any types of nematocyst sting, and it is likely that they have evolved to utilize venomous jellyfish as a food in the open sea, where food may be scarce.     

Exceptionally preserved jellyfishes from the Middle Cambrian

Cnidarians represent an early diverging animal group and thus insight into their origin and diversification is key to understanding metazoan evolution. Further, cnidarian jellyfish comprise an important component of modern marine planktonic ecosystems. Here we report on exceptionally preserved cnidarian jellyfish fossils from the Middle Cambrian (approximately 505 million years old) Marjum Formation of Utah. These are the first described Cambrian jellyfish fossils to display exquisite preservation of soft part anatomy including detailed features of structures interpreted as trailing tentacles and subumbrellar and exumbrellar surfaces. If the interpretation of these preserved characters is correct, their presence is diagnostic of modern jellyfish taxa. These new discoveries may provide insight into the scope of cnidarian diversity shortly after the Cambrian radiation, and would reinforce the notion that important taxonomic components of the modern planktonic realm were in place by the Cambrian period.     

Suspension-feeding mechanisms of the armoured sea cucumber Psolus chitinoides Clark

The armoured sea cucumber Psolus chitinoides Clark feeds on suspended particulate matter by means of tentacle ensnarement and the adhesive papillae of the tentacle buds. The latter provide the only ‘sticky’ surface on the feeding tentacles. Electron microscope preparations of the tentacle tips show the adhesive papillae to be comprised of both stout, warty papillary cells which appear to secrete the adhesive material used in the capture of food, and slender, uniciliated cells which may function to disengage food from the tentacle papillae during ingestion. Tentacular response to olfactory and mechanical stimuli together with ultrastructural evidence indicate that the papular cells may also function in a sensory capacity.     

The jellyfish buffet: jellyfish enhance seabird foraging opportunities by concentrating prey

High levels of jellyfish biomass have been reported in marine ecosystems around the world, but understanding of their ecological role remains in its infancy. Jellyfish are generally thought to have indirect negative impacts on higher trophic-level predators, through changes in lower trophic pathways. However, high densities of jellyfish in the water column may affect the foraging behaviour of marine predators more directly, and the effects may not always be negative. Here, we present novel observations of a diving seabird, the thick-billed murre, feeding on fish aggregating among the long tentacles of large jellyfish, by using small video loggers attached to the birds. We show that the birds encountered large jellyfish, Chrysaora melanaster, during most of their dives, commonly fed on fish associated with jellyfish, and appeared to specifically target jellyfish with a high number of fish aggregating in their tentacles, suggesting the use of jellyfish may provide significant energetic benefits to foraging murres. We conclude that jellyfish provide feeding opportunities for diving seabirds by concentrating forage fish, and that the impacts of jellyfish on marine ecosystems are more complex than previously anticipated and may be beneficial to seabirds.     

Tentacular diversity in deep-sea deposit-feeding holothurians: implications for biodiversity in the deep sea

The tentacles of deep-sea holothurians show a wide range of morphological diversity. The present paper examines gross tentacle morphology in surface deposit feeding holothurians from a range of bathymetric depths. Species studied included the elasipods: Oneirophanta mutabilis, Psychropotes longicauda and Benthogone rosea and the aspidochirotids: Paroriza prouhoi, Pseudostichopus sp., Bathyplotes natans and Paroriza pallens. The sympatric abyssal species Oneirophanta mutabilis, Psychropotes longicauda and Pseudostichopus sp. show subtle differences in diet and the structure and filling patterns of the gut that suggest differences in feeding strategies which may represent one mechanism to overcome competition for food resources in an environment where nutrient resources are considered to be, at least periodically, limiting. Interspecific differences in tentacle functional morphology and digestive strategies, which reflects taxonomic diversity could be explained in terms of Sanders'; Stability–Time Hypothesis. Since different tentacle types will turn over sediments to different extents, their impact on sedimentary communities will be enormous so that high diversity in meiofaunal communities may be explained most simply by Dayton and Hessler's Biological Disturbance Hypothesis.     

VARIATION IN HYDRA'S TENTACLE NUMBERS AS A FUNCTION OF TEMPERATURE

Chlorohydra uiridissima whose tentacle number is altered at different temperatures, was studied to see how other developmental variables changed as a function of temperature. The results suggest that temperature is instrumental in establishing the size of bud and tentacle primordia, but the number of primordia present may play a limiting role.

Animals were cultured at 18, 23 and 28°C and shifted between the extreme temperatures. Large animals with 8 tentacles, small animals with 5 tentacles, and intermediate animals with 6 and 7 tentacles served as parents. Buds and parents were monitored daily and scored for numbers of buds and tentacles.

Temperature, not parental size, determined the size of the buds. At the lower temperature buds were produced more slowly and initiated less frequently, but occurred in greater numbers per parent and had more tentacles than at the higher temperatures. The duration of bud development also increased at lower temperature, but at the lowest temperature the duration of bud development was not correlated with tentacle numbers on buds.

Changes in the frequency of bud initiation and the duration of bud development induced by changing temperature did not parallel changes in the number of tentacles produced on buds. Animals shifted from 18°C to 28°C underwent rapid increases in the rate of bud initiation and rapid shortening in the duration of bud development, while animals shifted from 28°C to 18°C underwent equally rapid changes in the opposite directions. The number of tentacles produced on buds, however, changed slowly to that characteristic of buds acclimated to the new temperatures. The frequency of bud initiation and the duration of bud development, therefore, do not determine tentacle number.

The number of tentacles already present seems to limit possibilities for adding new tentacles. Parents with five tentacles were especially likely to undergo upward changes in their tentacle number while parents with eight tentacles were resistant to such changes.     

An IQGAP-related gene is activated during tentacle formation in the simple metazoan Hydra

Differentiation of body column epithelial cells into tentacle epithelial cells in Hydra is accompanied by changes in both cell shape and cell-cell contact. The molecular mechanism by which epithelial cells acquire tentacle cell characteristics is unknown. Here we report that expression of a Hydra homologue of the mammalian IQGAP1 protein is strongly upregulated during tentacle formation. Like mammalian IQGAP, Hydra IQGAP1 contains an N-terminal calponin-homology domain, IQ repeats and a conserved C terminus. In adult polyps a high level of Hydra IQGAP1 mRNA is detected at the basis of tentacles. Consistent with a role in tentacle formation, IQGAP1 expression is activated during head regeneration and budding at a time when tentacles are emerging. The observations support the previous hypothesis that IQGAP proteins are involved in cytoskeletal as well as cell-cell contact rearrangements. Received: 25 January 2000 / Accepted: 2 May 2000     

The feeding behaviour of a deep-sea holothurian, Stichopus tremulus (Gunnerus) based on in situ observations and experiments using a Remotely Operated Vehicle

Using a Remotely Operated Vehicle (ROV) to deploy an in situ cage experiment incorporating fluorescent Luminophore particle tracers, the gut throughput time of the deposit feeding holothurian, Stichopus tremulus (Gunnerus) was determined as 23.73 h (S.D.±2.3). For a range of individuals examined at different depths (350-500 m) and locations, throughput times varied between 19 and 26 h irrespective of animal size or gut tract length. In situ video observations of feeding behaviour showed that this species uses fine oral papillae in a ‘sweeping’ motion to target particles on the seafloor. Following detection of a food source fine-branched digitate tentacles collect a large range of sediment fragments from the seabed. The main types of particles ingested include silica fragments (<20 >500 μm), pelagic foraminifera, benthic foraminifera, fine phytodetrital remains and occasional larger rock fragments (∼1 cm). Ingested sediment consisted mainly of very fine silica fragments (∼50 μm) accounting for over 50% of the total gut contents. Frame-by-frame video analysis revealed that the particle handling time (i.e. the time taken for a tentacle insertion and the subsequent collection of food) was found to be ∼54 s. Only 10 of the 20 feeding tentacles were simultaneously employed during feeding. Use of tentacles appeared to be in sequence, alternating between the reserve and active tentacles. Estimating the rate of movement over the seabed and the total effective capture area of each tentacle, the impact of this animal on the turnover and quality of surface sediment at this deepwater site is potentially substantial. The in situ experiments provided a significant improvement over previous methods used to investigate deep-sea deposit feeders and represent a useful concept for further in situ deep-sea research using an industrial ROV.     

THE ULTRASTRUCTURE OF PHALACROCLEPTES VERRUCIFORMIS, AN UNCILIATED CILIATE PARASITIZING THE POLYCHAETE SCHIZOBRANCHIA INSIGNIS

The organization of Phalacrocleptes verruciformis is, in general, less complex than that of other ciliates, and no kinetosomes have been observed. However, there are numerous suctorial tentacles at the surface of the body, and the pellicle is characterized by close-set villus-like projections. The tentacles are very small (about 430 mµ in length, and about the same in diameter), but show the essential features of tentacles of suctorians such as Tokophrya, Podophrya, and Ephelota. Each tentacle is reinforced by eight pairs of fibrils arranged concentrically just within its wall, and contains a single missile-like body (MLB). The tentacles become attached to the cilia of the host, and serve for feeding upon the plasmatic contents of the cilia as well as for maintaining contact with the host. The MLB's originate in the endoplasm, and then migrate toward the surface and become incorporated into the tentacles. When feeding is initiated, the membrane covering the outermost nozzle-like portion of the MLB becomes continuous with the membrane of the cilium, and there are other changes in the structure of the MLB which suggest enzymatic activity. Although it appears that Phalacrocleptes is a suctorian, the complete absence of kinetosomes sets this organism apart from other members of the group.