The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Joseph W Burnett - One of the best experts on this subject based on the ideXlab platform.
-
Characterization of Chrysaora quinquecirrha (sea nettle) nematocyst venom collagenase
Comparative Biochemistry and Physiology B, 2010Co-Authors: Gary J Calton, I. Neeman, Joseph W BurnettAbstract:Abstract 1. 1. The collagenase isolated from Chrysaora quinquecirrha (sea nettle) nematocyst venom was purified 237 fold using three sequential ion exchange chromatographic steps. 2. 2. The collagenase had optimal activity at physiological pH and temperature ranges. 3. 3. The enzyme was activated by Ca 2+ and Na + and reversibly inhibited by EDTA. 4. 4. The enzyme was not inhibited by phenylmethyl-sulfonyl fluoride but a number of chelating agents, cysteine, and many metal ions inhibited the collagenase.
-
two new actions of sea nettle Chrysaora quinquecirrha nematocyst venom studies on the mechanism of actions on complement activation and on the central nervous system
Toxicon, 2004Co-Authors: Takatoshi Ishikawa, Ivana Vucenik, Abulkalam M Shamsuddin, Florin Niculescu, Joseph W BurnettAbstract:Chrysaora quinquecirrha (sea nettle) nematocyst venom is lethal to rainbow killifish (Adina xenica) when injected intraperitoneally or topically applied to the exposed brain or denuded epithelium. The lethal activity is thermostable requiring 100 °C heat for inactivation. This paper reports here for the first time that the venom also activates the complement system with the subsequent formation of the C5b-9 terminal complement complex. The events are associated with both a strong chemoattractant release and the tissue damage. These are also, at least in part, responsible for the pathogenesis of some clinical signs and symptoms associated to the jellyfish stings.
-
Immunochromatography and cardiotoxicity of sea nettle (Chrysaora quinquecirrha) polyps and cysts.
Toxicon, 2002Co-Authors: C.erik Olson, David G. Cargo, Gary J Calton, Joseph W BurnettAbstract:Abstract The cardiotoxicity and polypeptide content of sea nettle (Chrysaora quinquecirrha) polyps and cysts were studied. Crude polyp preparations were lethal to mice. Both crude polyp and cyst preparations were toxic to embryonic chick cardiocytes. The polyp cardiotoxin factor was purified ten-fold by immunosorbent chromatography using anti-sea nettle or anti-man-o'war (Physalia physalis) monoclonal antibodies. Even though the polyps were incubated at a constant temperature, it appeared that there was an inverse relationship between the presence of proteins of 160,000 and 55,000 mol. wt as winter progressed.
-
toxinological studies on the nematocyst venom of Chrysaora achlyos
Toxicon, 2000Co-Authors: Faisal F Y Radwan, Lisaann Gershwin, Joseph W BurnettAbstract:Abstract Nematocyst venoms from both oral arms and lappets of Chrysaora achlyos were prepared and found to have factors producing mouse lethality, hemolysis and hepatocyte toxicity. These venoms had less potency than those of Chrysaora quinquecirrha a phylogenetic, congeneric cousin. Envenomated bathers had significant species-specific anti venom IgG and also cross-reacting antibody to Chrysaora quinquecirrha nematocyst venoms. There were similarities and contrasts in the capillary electropherograms and sodium dodecyl sulfate (SDS) gels between C. achlyos nematocyst venoms and those of their C. quinquecirrha counterparts.
-
Chrysaora achlyos a remarkable new species of scyphozoan from the eastern pacific
The Biological Bulletin, 1997Co-Authors: Joel W Martin, Lisaann Gershwin, Joseph W Burnett, David G. Cargo, David A BloomAbstract:An enormous new species of scyphozoan jellyfish, Chrysaora achlyos, is described from the eastern Pacific. The description is based primarily on color photographs and video footage of living animals and the morphology of four specimens collected in 1989. The natural history, life cycle, and sporadic appearance of the species all are unknown. The species appeared most recently in large numbers in 1989 but has appeared at least twice previously in this century; published photographs (unlabeled or incorrectly identified) appeared in 1926 and 1965. The species is easily distinguished by its size and coloration from other known species in the genus, all of which are considerably smaller. Morphological characters are described, and limited data on nematocyst types are presented. Because of the size of the new species and the known potency of the sting of congeners, we mention briefly the possible consequences of human contact.
Ana Carolina Morandini - One of the best experts on this subject based on the ideXlab platform.
-
jellyfish Chrysaora lactea cnidaria semaeostomeae aggregations in southern brazil and consequences for human stings
Submission article platform - Latin American Journal of Aquatic Research, 2017Co-Authors: Antonio C Marques, Vidal Haddad, Lenora Rodrigo, Emanuel Marquesdasilva, Ana Carolina MorandiniAbstract:The frequency of blooming is generating a world-wide discussion about medusae population explosions, mainly those associated with accidents. We report over 20,000 accidents caused by Chrysaora lactea (Scyphozoa) in the State of Parana (Brazil) during the austral summer of 2011-2012. Accidents were considered mild, but almost 600 cases were treated in emergency services, with either toxic and allergic reactions, some with systemic manifestations. We proposed non-exclusive hypotheses to explain this large number of cases.
-
jellyfish Chrysaora lactea cnidaria semaeostomeae aggregations in southern brazil and consequences of stings in humans
Latin American Journal of Aquatic Research, 2014Co-Authors: Antonio C Marques, Vidal Haddad, Lenora Rodrigo, Emanuel Marquesdasilva, Ana Carolina MorandiniAbstract:The frequency of jellyfish blooms is generating a world-wide discussion about medusae population explosions, mainly those associated with stings. We report over 20,000 envenomations caused by Chrysaora lactea (Scyphozoa) in the State of Parana (southern Brazil) during the austral summer of 2011-2012. Envenomations were considered mild, but almost 600 cases were treated in emergency services, with either toxic and allergic reactions, some with systemic manifestations. We proposed non-exclusive hypotheses to explain this large number of cases.
-
field and laboratory observations on predation and prey selectivity of the scyphomedusa Chrysaora cf caliparea in southeast indian waters
Journal of Ocean University of China, 2011Co-Authors: Govindan Kanagaraj, Ana Carolina Morandini, P Ezhilarasan, P Sampathkumar, Velayudhan Pillai SivakumarAbstract:Chrysaora cf. caliparea, one of the most abundant medusae species in India, seems to be an important predator in the coastal waters of Bay of Bengal. The ability of Chrysaora cf. caliparea to feed at maximum rate in high prey concentrations implies that this jellyfish can efficiently exploit dense prey patches, at least for a short period. This study presents preliminary information regarding digestion and feeding rate upon copepods in a warm water environment. The ingestion rate of the average-sized medusae Chrysaora cf. caliparea is well balanced in nature, which in turn implies that this jellyfish is tuned for optimal utilization of available prey resources. Comparison with earlier research indicates that prey escape speed is one important factor governing which prey will be captured. A full understanding of predation mechanics awaits further investigation of both predator and prey behavior. However, because of the scarcity of long-term quantitative population data most insights have to be made indirectly. Nevertheless, low abundance of Chrysaora cf. caliparea in the water column during summer (May 2007) and the overall annual abundance seem not to considerably affect the zooplankton population, especially copepods. The present work contributes to the knowledge of prey-predator relationship of the forgotten fauna in Indian waters, which is especially crucial for understanding the process of ecological recovery of coastal water environment.
-
revision of the genus Chrysaora peron lesueur 1810 cnidaria scyphozoa
Zootaxa, 2010Co-Authors: Ana Carolina Morandini, Antonio C MarquesAbstract:Revision of the scyphozoan genus Chrysaora Peron & Lesueur, 1810 was undertaken from observations on museum material (Brazil, Europe, and USA), on living specimens in nature, and on life-cycles of some species cultured under laboratory conditions. A total of 168 museum lots, some of them having many medusae, were inspected. Included amongst these were nine type specimens. The genus comprises 13 valid species (Chrysaora achlyos, C. chinensis, C. colorata, C. fulgida, C. fuscescens, C. hysoscella, C. lactea, C. melanaster, C. pacifica, C. pentastoma, C. plocamia, and C. quinquecirrha), one species inquirenda (Chrysaora caliparea), and two doubtful species (C. kynthia and C. wurlerra). Differentiation of species is based mostly on tentacle number, shape of radial septa, order of tentacle development, colouration, and measurements of nematocysts. We resurrect C. chinensis for specimens from southeast Asia. Chrysaora pacifica is considered valid and distinct from C. melanaster based on tentacle number and nematocyst complement. Mediterranean specimens assigned to C. hysoscella are hermaphroditic and thereby considered distinct from those of C. fulgida from west Africa. Chrysaora achlyos (northeast Pacific) and C. plocamia (southeast Pacific and southwest Atlantic) are geographically isolated but morphologically identical, being distinguished only by colour pattern. The recently described C. southcotti is considered a junior synonym of C. pentastoma. The Australian C. kynthia and C. wurlerra, here considered nomina dubia, merit further study. Our phylogenetic hypothesis indicates that the genus Chrysaora forms a monophyletic group, with C. colorata, C. plocamia, and C. achlyos having a basal position in the phylogeny. Species with more than 24 tentacles (formerly assigned to the genus Dactylometra) form a clade with a derived position.
-
redescription of Chrysaora lactea eschscholtz 1829 cnidaria scyphozoa from the brazilian coast with designation of a neotype
Zootaxa, 2006Co-Authors: Ana Carolina Morandini, Fabio Lang Da Silveira, P F S CorneliusAbstract:A redescription of the species Chrysaora lactea from the western South Atlantic is given based on live and preserved specimens from the Brazilian, Uruguayan and Argentinean coasts, and a neotype specimen is designated. The species is one of the commonest scyphomedusae in Brazilian coastal waters, reaching up to 25 cm in bell diameter with several different colour patterns (mainly milkywhite). The species is recorded with certainty from Jamaica to the northern coast of Argentina, and can be distinguished from its congeners primarily by the order of the development of tentacles (2nd, 3rd, 1st, 3rd, 2nd).
Gerhard Jarms - One of the best experts on this subject based on the ideXlab platform.
-
Effects of low salinity on settlement and strobilation of scyphozoa (Cnidaria): Is the lion’s mane Cyanea capillata (L.) able to reproduce in the brackish Baltic Sea?
Hydrobiologia, 2010Co-Authors: Sabine Holst, Gerhard JarmsAbstract:Several species of scyphozoan medusae occur in river estuaries and other brackish waters but it is often unknown if the planulae settle and the scyphopolyps reproduce in those low-salinity waters. In the present study, scyphozoan species from the German Bight (North Sea) were tested in laboratory experiments to investigate their tolerance of low salinity. Planula larvae released from medusae in salinity 32 were still active after the salinity was reduced to 10 ( Cyanea capillata , Cyanea lamarckii ) and to 7 ( Chrysaora hysoscella ) in laboratory treatments. Planulae did not settle on the undersides of floating substrates when salinity was reduced to
-
the life cycle of Chrysaora lactea eschscholtz 1829 cnidaria scyphozoa with notes on the scyphistoma stage of three other species
Hydrobiologia, 2004Co-Authors: Ana Carolina Morandini, Fabio Lang Da Silveira, Gerhard JarmsAbstract:The life cycle of Chrysaora lactea Eschscholtz, 1829, a common species on the Brazilian coast, is described. Mature medusae were collected and isolated in a planktonkreisel, whereupon planulae appeared after 1–2 days. These planulae settled and metamorphosed into polyps. Fully developed scyphistomae typically possessed 16 tentacles, and on strobilation produced from 2 to 10 ephyrae. The ephyrae were transparent and had characteristic nematocyst warts on the exumbrella. Tentacles first appeared near the margin on the subumbrella. Ephyrae and young medusae were maintained in laboratory conditions up to 7 months.
Mark J. Gibbons - One of the best experts on this subject based on the ideXlab platform.
-
There are three species of Chrysaora (Scyphozoa: Discomedusae) in the Benguela upwelling ecosystem, not two
Zootaxa, 2020Co-Authors: S. Neethling, Adriaan Engelbrecht, A.c. Morandini, K.m. Bayha, H. Skrypzeck, Mark J. GibbonsAbstract:Chrysaora (Pèron & Lesueur 1810) is the most diverse genus within Discomedusae, and 15 valid species are currently recognised, with many others not formally described. Since Chrysaora fulgida (Reynaud 1830) was first recognised as occurring off the south west (SW) coast off South Africa, the species has been variously synonymised with Chrysaora hysoscella (Linnaeus 1767) and Chrysaora africana (Vanhöffen 1902). Using DNA evidence alongside multivariate tools to analyse quantitative morphometric and meristic data, as well as information from the cnidome, we unambiguously separate C. fulgida from C. hysoscella; we resurrect C. africana as a valid species and recognise a new species, Chrysaora agulhensis sp. nov. Full descriptions of C. fulgida, C. africana and C. agulhensis sp. nov. are provided. The species have different geographical patterns of distribution around the region, with restricted areas of overlap: C. agulhensis sp. nov. is found along the southern coast of South Africa and over the Agulhas Bank, C. fulgida extends from Cape Point in South Africa to southern Angola, and C. africana can be found from southern Namibia northwards to the Gulf of Guinea. The species can be readily separated in the field by a combination of tentacle/lappet number and shape, colour patterns and the form of the oral arms.
-
biometry and size distribution of Chrysaora hysoscella cnidaria scyphozoa and aequorea aequorea cnidaria hydrozoa off namibia with some notes on their parasite hyperia medusarum
Journal of Plankton Research, 2001Co-Authors: Emmanuelle Buecher, Conrad Sparks, Andrew S Brierley, Helen Boyer, Mark J. GibbonsAbstract:Novel data on the biometry, size distribution and parasites of Aequorea aequorea and Chrysaora hysoscella are provided from investigations conducted during summer and winter in the northern Benguela ecosystem. The relationship between mass and diameter of C. hysoscella did not change on a seasonal basis, and this possibly reflects the aseasonal nature of the food environment. The changes in the size structure of C. hysoscella across the shelf and with depth agree with postulated population maintenance strategies in the region. Aequorea aequorea was not strongly parasitized, but C. hysoscella was subject to occasional parasitism by Hyperia medusarum, especially in winter when C. hysoscella is thought to reproduce. Parasites were distributed in a typical, negative-binomial manner on their hosts, but load was independent of host size. As medusae increased in diameter so H. medusarum tended to move from other tissues to the gonads.
-
observations on the distribution and relative abundance of the scyphomedusan Chrysaora hysoscella linne 1766 and the hydrozoan aequorea aequorea forskal 1775 in the northern benguela ecosystem
Hydrobiologia, 2001Co-Authors: Conrad Sparks, Emmanuelle Buecher, Andrew S Brierley, Bjorn Erik Axelsen, Helen Boyer, Mark J. GibbonsAbstract:Observations on the abundance of medusae at the surface were conducted in the northern Benguela ecosystem, over the period August 1997–June 1998. The results suggest that Chrysaora hysoscella is found inshore, whereas Aequorea aequorea tends to be found offshore. Although these relative observations are subject to bias caused by seasonal changes in the survey area, they are generally supported by the results of correlation analyses, and by the results of a more quantitative, cross-shelf trawl survey. Both species of medusae display marked patchiness, and can be very abundant. They appear to have mostly non-overlapping patterns of distribution in the upper layers of the water column, and so are able exert a consistent predation pressure across the width of the continental shelf. The estimates of biomass obtained are used as input variables to existing models of energy flow within the ecosystem.
Jennifer E. Purcell - One of the best experts on this subject based on the ideXlab platform.
-
predicting the distribution of the scyphomedusa Chrysaora quinquecirrha in chesapeake bay
Marine Ecology Progress Series, 2007Co-Authors: Mary Beth Decker, Jennifer E. Purcell, Raleigh R Hood, Chris W Brown, Thomas F Gross, J C Matanoski, R O Bannon, E M SetzlerhamiltonAbstract:Jellyfish blooms are important events controlling plankton dynamics in coastal waters worldwide, yet factors that influence bloom development are not well understood. We used the scyphomedusa Chrysaora quinquecirrha as a model to examine physical factors that control jellyfish populations and to develop an ecological forecasting system. Over 700 in situ observations collected from Chesapeake Bay and its tributaries during 1987-2000 were used to develop habitat models that predict the probability of occurrence and the likely concentration of medusae as a function of sea- surface temperature and salinity. Medusae were found within a relatively narrow range of tempera- ture (26 to 30°C) and salinity (10 to 16). Regression analyses reveal that a combination of temperature and salinity is a significant predictor of medusa occurrence. Assessments of the predictive perfor- mance of these models using medusae and environmental data collected at independent survey sites (n = 354) indicated that model-predicted medusa occurrence and concentration correspond well with observations. Our models can be forced with near-real time and retrospective estimates of tempera- ture and salinity to generate probability of occurrence maps of C. quinquecirrha medusa presence and abundance in order to better understand how this top predator varies in space and time, and how this species could potentially affect energy flow through the Chesapeake Bay system.
-
Effects of low dissolved oxygen on survival and asexual reproduction of scyphozoan polyps (Chrysaora quinquecirrha)
Hydrobiologia, 2001Co-Authors: Robert H. Condon, Mary Beth Decker, Jennifer E. PurcellAbstract:Hypoxic conditions are common in many coastal environments such as Chesapeake Bay. While medusae appear to be quite tolerant of low dissolved oxygen (DO) concentrations, the effects of hypoxia on the benthic polyp stages are unknown. Chrysaora quinquecirrha (DeSor) polyps, and were subjected to 5 DO treatments (air-saturated [control], 3.5, 2.5, 1.5 and 0.5 mg l−1) in the laboratory. Polyp survival and development were documented over 24 d. Virtually no mortality occurred in any treatment during the first 5 d. Total polyp mortality after 24 d was 59.3% at the lowest DO concentration, whereas
-
Temperature, salinity and food effects on asexual reproduction and abundance of the scyphozoan Chrysaora quinquecirrha
Marine Ecology Progress Series, 1999Co-Authors: Jennifer E. Purcell, Jacques R. White, David A. Nemazie, David A WrightAbstract:Outbreaks of jellyfish are reported worldwide, yet the environmental factors that control the sizes of jellyfish populations are not well understood. The scyphomedusan Chrysaora quinquecirrha occurs in the mesohaline portion of Chesapeake Bay each summer. Population sizes of the medusae show dramatic annual variations that are correlated with salinity and temperature. We measured the total numbers of ephyrae and polyps produced by benthic polyps of C. quinquecirrha in laboratory experiments lasting 42 d, and found that temperature (15, 20, 25°C) was not a statistically significant factor at low salinities (5 to 20‰); however, ephyra production increased significantly with increasing temperature at high salinities (20 to 35‰). Conversely, each 5°C decrease in temperature delayed strobilation (ephyra production) by about 1 wk. Salinity significantly affected the numbers of ephyrae and polyps produced in all experiments. Ephyra and polyp production was lower at both low (
-
swimming and feeding by the scyphomedusa Chrysaora quinquecirrha
Marine Biology, 1997Co-Authors: M D Ford, John H Costello, Karla B Heidelberg, Jennifer E. PurcellAbstract:The semaeostome scyphomedusa, Chrysaora quinquecirrha (Desor, 1848), is an abundant and important planktonic predator in estuaries and coastal waters of the eastern USA during the summer. We videotaped free-swimming medusae in the laboratory and in the field in order to determine the relationship between swimming motions and prey encounter with capture surfaces. Medusae were collected from the Choptank River (Chesapeake Bay) in September 1992 and in the Niantic River, Connecticut, USA in July 1994. We used newly hatched Artemia sp. nauplii and fluorescein dye to trace water motions around swimming medusae. Swimming results in a pulsed series of toroids which travel along the medusan oral arms and tentacles. Prey are entrained in this flow and the location of naupliar encounter was influenced by the phase of the pulsation cycle during which entrainment occurred. Flow-field velocities, measured by tracking particles adjacent to the bell margin during contraction, increased with bell diameter.
-
escape of the ctenophore mnemiopsis leidyi from the scyphomedusa predator Chrysaora quinquecirrha
Marine Biology, 1997Co-Authors: T A Kreps, Jennifer E. Purcell, Karla B HeidelbergAbstract:The ctenophore Mnemiopsis leidyi A. Agassiz, 1865 is known to be eaten by the scyphomedusan Chrysaora quinquecirrha (Desor, 1948), which can control populations of ctenophores in the tributaries of Chesapeake Bay. In the summer of 1995, we videotaped interactions in large aquaria in order to determine whether M. leidyi was always captured after contact with medusae. Surprisingly, M. leidyi escaped in 97.2% of 143 contacts. The ctenophores increased swimming speed by an average of 300% immediately after contact with tentacles and 600% by mid-escape. When caught in the tentacles of C. quinquecirrha, the ctenophores frequently lost a portion of their body, which allowed them to escape. Lost parts regenerated within a few days. The striking ability of M. leidyi to escape from C. quinquecirrha may be critically important in maintaining ctenophore populations in situ.