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1

Venom Proteome of the Box Jellyfish Chironex fleckeri  

PubMed Central

The nematocyst is a complex intracellular structure unique to Cnidaria. When triggered to discharge, the nematocyst explosively releases a long spiny, tubule that delivers an often highly venomous mixture of components. The box jellyfish, Chironex fleckeri, produces exceptionally potent and rapid-acting venom and its stings to humans cause severe localized and systemic effects that are potentially life-threatening. In an effort to identify toxins that could be responsible for the serious health effects caused by C. fleckeri and related species, we used a proteomic approach to profile the protein components of C. fleckeri venom. Collectively, 61 proteins were identified, including toxins and proteins important for nematocyte development and nematocyst formation (nematogenesis). The most abundant toxins identified were isoforms of a taxonomically restricted family of potent cnidarian proteins. These toxins are associated with cytolytic, nociceptive, inflammatory, dermonecrotic and lethal properties and expansion of this important protein family goes some way to explaining the destructive and potentially fatal effects of C. fleckeri venom. Venom proteins and their post-translational modifications (PTMs) were further characterized using toxin-specific antibodies and phosphoprotein/glycoprotein-specific stains. Results indicated that glycosylation is a common PTM of the toxin family while a lack of cross-reactivity by toxin-specific antibodies infers there is significant divergence in structure and possibly function among family members. This study provides insight into the depth and diversity of protein toxins produced by harmful box jellyfish and represents the first description of a cubozoan jellyfish venom proteome. PMID:23236347

Brinkman, Diane L.; Aziz, Ammar; Loukas, Alex; Potriquet, Jeremy; Seymour, Jamie; Mulvenna, Jason

2012-01-01

2

Rapid short term and gradual permanent cardiotoxic effects of vertebrate toxins from Chironex fleckeri (Australian box jellyfish) venom.  

PubMed

The vertebrate cardiotoxic components of the venom produced by the Australian box jellyfish, Chironex fleckeri, have not previously been isolated. We have uncovered for the first time, three distinct cytotoxic crude fractions from within the vertebrate cardiotoxic peak of C. fleckeri venom by monitoring viability of human muscle cells with an impedance based assay (ACEA xCELLigence system) measuring cell detachment as cytotoxicity which was correlated with a reduction in cell metabolism using a cell proliferation (MTS) assay. When the effects of the venom components on human cardiomyocytes and human skeletal muscle cells were compared, two fractions were found to specifically affect cardiomyocytes with distinct temporal profiles (labelled Crude Toxic Fractions (CTF), ? and ?). A third fraction (CTF-?) was toxic to both muscle cell types and therefore not cardio specific. The vertebrate, cardio specific CTF-? and CTF-?, presented distinct activities; CTF-? caused rapid but short term cell detachment and reduction in cell metabolism with enhanced activity at lower concentrations than CTF-?. This activity was not permanent, with cell reattachment and subsequent increased metabolism of heart muscle cells observed when exposed to all but the highest concentrations of CTF-? tested. The cytotoxic effect of CTF-? took twice as long to act on the cells compared to CTF-?, however, the activity was permanent. Furthermore, we showed that the two fractions combined have a synergistic effect causing a much stronger and faster cell detachment (death) when combined than the sum of the individual effects of each toxin. These data presented here improves the current understanding of the toxic mechanisms of the Australian box jellyfish, C. fleckeri, and provides a basis for in vivo research of these newly isolated toxic fractions. PMID:24462661

Chaousis, Stephanie; Smout, Michael; Wilson, David; Loukas, Alex; Mulvenna, Jason; Seymour, Jamie

2014-03-01

3

Jellyfish stings  

MedlinePLUS

... of the most common jellyfish found along the Atlantic and Gulf coasts Sea wasp ( Chironex fleckeri , Chiropsalmus ... war or sea nettle, wash with salt water (ocean water is okay, but make sure you do ...

4

The effect of vinegar on discharged nematocysts of Chironex fleckeri - Reply.  

PubMed

We thank Yanagihara and Chen for their comments and for the opportunity to further the discussion. Our statistician has re-examined (and reanalysed) these data, and we have supplied our data to an independent statistician (who supported our subsequent re-analysis) and are more than willing to supply these data to the journal editors should they feel this is necessary. Furthermore, the manuscript was independently reviewed by two reviewers who expressed no concern over our analysis. We are confident of our results. Yanagihara and Chen have incorrectly assumed that the errors displayed in Figure 2 are SEM. These errors represent the 95% confidence limits (CL) and as such their arguments are invalid. Furthermore, they outline that no statistical significance was provided for the specific W4 vs. W3 comparison. Although no specific statistics were displayed in the article, we do outline that LSD post hoc analysis was conducted and the means and 95% CL (as signified in Figure 2) that were significantly different were listed. This analysis showed that the percentage of venom discharged after the application of voltage (W2) and after the application of vinegar (W4) were significantly different from one another and both were significantly higher than either the initial before-voltage percentage (W1) or after the third washing (W3) after voltage application. It is further suggested that the samples used (W1 to W4) are internally matched samples and hence ANOVA is inappropriate. They suggest that a simple t-test would give different results. To alleviate their concerns, we have reanalysed the data using a paired t-test, comparing the level of protein present after the third washing (W3) since voltage was applied to the tentacle and the amount of protein present after vinegar was applied (W4). We paired each sample with itself (which effectively removes the issues surrounding analysis of internally matched samples). This analysis showed that the difference between the matched pairs was significant (t = 8.938, df = 2, P = 0.012). We further reanalysed these data comparing the mean protein expression after vinegar application (W4) to a standard value (23.2%) which was the mean percentage found after three washings (W3) post voltage application. Once again, the difference was found to be significant (t = 6.012, df = 2, P = 0.027). We would argue, however, that the use of t-tests, as suggested by Yanagihara and Chen, is inappropriate owing to a possible non-normal distribution of the data. To address this, we further analysed these data using a non-parametric median test to a binomial distribution for data collected after the third washing (W3) post voltage application and data collected after the application of vinegar (W4). We used a one-sample median test to a binomial. This statistical test is non-parametric as no assumption is made about the form of the population distribution except that it is continuous. This analysis once again revealed a significant difference between the treatments (Zb = 1.73, P = 0.04) and, as such, the amount of protein after vinegar application is greater than after the washing protocol; that is, the application of vinegar increases the amount of venom expressed. Finally, we have reanalysed our data using a Friedman's test (as suggested by another independent biostatistician consulted by the Editor) and once more found that the application of vinegar increased the presence of toxin (?2 = 9.0, df = 3, P = 0.029). We thank Yanagihara and Chen for pointing out an issue of the degrees of freedom listed. We realize there was a transcription error that was not identified by the authors within the proofs. Where it reads (F = 77.123x82), it should read (F = 77.123x8). Yanagihara and Chen have also expressed concerns about the press releases associated with this paper. We were contacted by the media as a result of the article's abstract release and the cover page of this journal for March 2014 with the heading "Does vinegar make box jellyfish stings worse?" Our sole press release (in response to the above

Welfare, Philippa; Little, Mark; Pereira, Peter; Seymour, Jamie

2014-09-01

5

Dose and time dependence of box jellyfish antivenom  

PubMed Central

Background The effectiveness of the currently available box jellyfish (Chironex fleckeri) antivenom has been subject of debate for many years. To assess whether the box jellyfish antivenom has the ability to attenuate venom-induced damage at cellular level, the present study analyzed the dose and time dependence of the antivenom in a cell-based assay. Methods Different doses of antivenom were added to venom and subsequently administered to cells and the cell index was measured using xCelligence Technology (ACEA Biosciences). Similarly, antivenom and venom were incubated over different time periods and cell survival measured as stated above. For both experiments, the cell index was plotted as a measure of cell survival against the dose or incubation time and significance was determined with the use of a one-way ANOVA with a LSD post hoc test. Results Increasing concentrations of antivenom significantly augmented cell survival, with a concentration of approximately five times the currently recommended dose for human envenomation, causing the first significant increase in cell survival compared venom alone. Further, cell survival improved with increasing incubation time of venom and antivenom prior to addition to the cells, indicating that box jellyfish antivenom requires approximately 70 minutes to neutralize C. fleckeri venom. Conclusion The presented results suggest that the currently recommended dose of antivenom requires adjustment, and more importantly, a human trial to test the effects of higher concentrations is also necessary. Further, antivenom has delayed neutralizing effects (i.e. after 70 minutes) which underlines the eminence of immediate and prolonged cardiopulmonary resuscitation in victims suffering from a C. fleckeri venom-induced cardiovascular collapse. PMID:25161664

2014-01-01

6

Jellyfish Stings, First Aid  

MedlinePLUS

... NOT wash or soak the affected area with fresh water if the injury occurred in salt water. DO ... weeks or more. Jellyfish stings sometimes occur in fresh water as well. Signs and Symptoms A jellyfish itself ...

7

A case of jellyfish sting.  

PubMed

Jellyfish sting may result in a wide range of symptoms from common erythematous urticarial eruptions to the rare box-jelly induced acute respiratory failure. In Taiwan, with the increasing frequency of international travel, cases of jellyfish sting to foreigners are on the rise. We report a case of jellyfish sting with the rare presentation of painless contact dermatitis. A 38-y-o man accidentally stepped on a sea urchin with his right foot during scuba diving in a beach in Thailand. Traditional therapy with vinegar was applied on the lesion. However, when he returned to Taiwan, erythematous patches on the left thigh with linear radiations to the leg were discovered. The skin lesions had bizzare shapes and showed progressive change. No pain or numbness was noticed. Jellyfish stingwas suspected, topical medications were applied, and the patient recovered without complication. Jellyfish stings usually result in a painful erythematous eruption. In this case, though the lesion involved a large surface, there was no pain. Delayed diagnosis of jellyfish sting was due to the atypical presentation and the physician's unfamiliarity to the Thai jellyfish sting. Awareness to the wide spectrum of jellyfish sting symptoms should be promoted. PMID:11474731

Lee, N S; Wu, M L; Tsai, W J; Deng, J F

2001-08-01

8

Dangerous jellyfish blooms are predictable.  

PubMed

The potentially fatal Irukandji syndrome is relatively common in tropical waters throughout the world. It is caused by the sting of the Irukandji jellyfish, a family of box jellyfish that are almost impossible to detect in the water owing to their small size and transparency. Using collated medical records of stings and local weather conditions, we show that the presence of Irukandji blooms in coastal waters can be forecast on the basis of wind conditions. On the Great Barrier Reef, blooms largely coincide with relaxation of the prevailing southeasterly trade winds, with average conditions corresponding to near zero alongshore wind on the day prior to the sting. These conditions are consistent with hypotheses long held by local communities and provide a basis for designing management interventions that have the potential to eliminate the majority of stings. PMID:24829278

Gershwin, Lisa-ann; Condie, Scott A; Mansbridge, Jim V; Richardson, Anthony J

2014-07-01

9

Micro- and Macrorheology of Jellyfish Extracellular Matrix  

PubMed Central

Mechanical properties of the extracellular matrix (ECM) play a key role in tissue organization and morphogenesis. Rheological properties of jellyfish ECM (mesoglea) were measured in vivo at the cellular scale by passive microrheology techniques: microbeads were injected in jellyfish ECM and their Brownian motion was recorded to determine the mechanical properties of the surrounding medium. Microrheology results were compared with macrorheological measurements performed with a shear rheometer on slices of jellyfish mesoglea. We found that the ECM behaved as a viscoelastic gel at the macroscopic scale and as a much softer and heterogeneous viscoelastic structure at the microscopic scale. The fibrous architecture of the mesoglea, as observed by differential interference contrast and scanning electron microscopy, was in accord with these scale-dependent mechanical properties. Furthermore, the evolution of the mechanical properties of the ECM during aging was investigated by measuring microrheological properties at different jellyfish sizes. We measured that the ECM in adult jellyfish was locally stiffer than in juvenile ones. We argue that this stiffening is a consequence of local aggregations of fibers occurring gradually during aging of the jellyfish mesoglea and is enhanced by repetitive muscular contractions of the jellyfish. PMID:22225792

Gambini, Camille; Abou, Berengere; Ponton, Alain; Cornelissen, Annemiek J.M.

2012-01-01

10

Exceptionally Preserved Jellyfishes from the Middle Cambrian  

PubMed Central

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 (?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. PMID:17971881

Cartwright, Paulyn; Halgedahl, Susan L.; Hendricks, Jonathan R.; Jarrard, Richard D.; Marques, Antonio C.; Collins, Allen G.; Lieberman, Bruce S.

2007-01-01

11

Exceptionally Preserved Jellyfishes from the Middle Cambrian  

E-print Network

and sea anemones, and Medusozoa, including scyphozoans (true jellyfish), cubozoans (box jellies), hydrozoans (hydroids, Hydra, and hydromedusae) and staurozoans (stalked medusae) [2]. Typically, medusozoan cnidarians have a pelagic, predatory jellyfish..., Anderson MM (2000) The first named Ediacaran body fossil; Aspidella terranovica. Palaeontology 43: 427–456. 17. Plummer PS (1980) Circular structures in a late Precambrian sandstone; fossil medusoids or evidence of fluidization? Trans Royal Soc S Aust 104...

Cartwright, Paulyn; Halgedahl, Susan L.; Hendricks, Jonathan R.; Jarrard, Richard D.; Marques, Antonio; Collins, Allen G.; Lieberman, Bruce S.

2007-10-01

12

Australian carybdeid jellyfish causing "Irukandji syndrome".  

PubMed

The Australian carybdeid jellyfish associated with Irukandji syndrome is Carukia barnesi, (Barnes' jellyfish). Other Australian carybdeid jellyfish that may be associated with the syndrome include Carukia shinju, Carybdea xaymacana, Malo maxima, Malo kingi, Alatina mordens, Gerongia rifkinae, and Morbakka fenneri ("Morbakka"). These small jellyfish are difficult to capture and identify. They are located offshore of the coasts of Australian states including Queensland, The Northern Territory, Western Australia and South Australia. The syndromic illness, resulting from a characteristic relatively minor sting, develops after about 30 minutes and consists of severe muscle pains especially of the lower back, muscle cramps, vomiting, sweating, agitation, vasoconstriction, prostration, hypertension and in cases of severe envenomation, acute heart failure. The mechanisms of actions of their toxins are obscure but they appear to include modulation of neuronal sodium channels leading to massive release of endogenous catecholamines (C. barnesi, A. mordens and M. maxima) and thereby to possible stress-induced cardiomyopathy. In addition, pore formation may occur in myocardial cellular membranes (C. xaymacana). In human cases of severe envenomation, systemic hypertension and myocardial dysfunction are associated with membrane leakage of troponin. Clinical management includes parenteral analgesia, antihypertensive therapy, oxygen and mechanical ventilation. No effective first-aid is known. Large knowledge gaps exist in biology of the jellyfish, their distribution, their toxins and mode of actions and in treatment of the Irukandji syndrome. PMID:22361384

Tibballs, James; Li, Ran; Tibballs, Heath A; Gershwin, Lisa-Ann; Winkel, Ken D

2012-05-01

13

Jellyfish stings and their management: a review.  

PubMed

Jellyfish (cnidarians) have a worldwide distribution. Despite most being harmless, some species may cause local and also systemic reactions. Treatment of jellyfish envenomation is directed at: alleviating the local effects of venom, preventing further nematocyst discharges and controlling systemic reactions, including shock. In severe cases, the most important step is stabilizing and maintaining vital functions. With some differences between species, there seems to be evidence and consensus on oral/topical analgesics, hot water and ice packs as effective painkillers and on 30 s application of domestic vinegar (4%-6% acetic acid) to prevent further discharge of unfired nematocysts remaining on the skin. Conversely, alcohol, methylated spirits and fresh water should be carefully avoided, since they could massively discharge nematocysts; pressure immobilization bandaging should also be avoided, as laboratory studies show that it stimulates additional venom discharge from nematocysts. Most treatment approaches are presently founded on relatively weak evidence; therefore, further research (especially randomized clinical trials) is strongly recommended. Dissemination of appropriate treatment modalities should be deployed to better inform and educate those at risk. Adequate signage should be placed at beaches to notify tourists of the jellyfish risk. Swimmers in risky areas should wear protective equipment. PMID:23434796

Cegolon, Luca; Heymann, William C; Lange, John H; Mastrangelo, Giuseppe

2013-01-01

14

Anthropogenic causes of jellyfish blooms and their direct consequences for humans: a review  

Microsoft Academic Search

Although recent articles state that jellyfish populations are increasing, most available evidence shows that jellyfish abundances fluctuate with climatic cycles. Reports of increasing prob- lems with jellyfish, especially in East Asia, are too recent to exclude decadal climate cycles. Jellyfish are infamous for their direct negative effects on human enterprise; specifically, they interfere with tourism by stinging swimmers, fishing by

Jennifer E. Purcell; Shin-ichi Uye; Wen-Tseng Lo

2007-01-01

15

PHYLOGENETIC SYSTEMATICS, TAXONOMY, AND BIOGEOGRAPHY OF JELLYFISH (CNIDARIA: MEDUSOZOA)  

E-print Network

The coastal shelf inhabiting box jellyfish (Cubozoa) represent the smallest class within Cnidaria with some 50 described species. A robust phylogenetic framework had been missing for Cubozoa. Herein, a molecular phylogeny ...

Bentlage, Bastian

2012-08-31

16

TWO DIMENSIONAL IMMERSED BOUNDARY SIMULATIONS OF SWIMMING JELLYFISH  

E-print Network

Simulations Of Swim- ming Jellyfish Examining Committee: Dr. Weiran Sun, Assistant Professor Chair Dr. John #12;"A journey of a thousand miles must begin with a single step." -- Lao-tzu vi #12;Acknowledgments

Stockie, John

17

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

Microsoft Academic Search

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

Laura M. Birsa; Peter G. Verity; Richard F. Lee

2010-01-01

18

Identification of genetically and oceanographically distinct blooms of jellyfish  

PubMed Central

Reports of nuisance jellyfish blooms have increased worldwide during the last half-century, but the possible causes remain unclear. A persistent difficulty lies in identifying whether blooms occur owing to local or regional processes. This issue can be resolved, in part, by establishing the geographical scales of connectivity among locations, which may be addressed using genetic analyses and oceanographic modelling. We used landscape genetics and Lagrangian modelling of oceanographic dispersal to explore patterns of connectivity in the scyphozoan jellyfish Rhizostoma octopus, which occurs en masse at locations in the Irish Sea and northeastern Atlantic. We found significant genetic structure distinguishing three populations, with both consistencies and inconsistencies with prevailing physical oceanographic patterns. Our analyses identify locations where blooms occur in apparently geographically isolated populations, locations where blooms may be the source or result of migrants, and a location where blooms do not occur consistently and jellyfish are mostly immigrant. Our interdisciplinary approach thus provides a means to ascertain the geographical origins of jellyfish in outbreaks, which may have wide utility as increased international efforts investigate jellyfish blooms. PMID:23287405

Lee, Patricia L. M.; Dawson, Michael N; Neill, Simon P.; Robins, Peter E.; Houghton, Jonathan D. R.; Doyle, Thomas K.; Hays, Graeme C.

2013-01-01

19

Cubozoan Venom-Induced Cardiovascular Collapse Is Caused by Hyperkalemia and Prevented by Zinc Gluconate in Mice  

PubMed Central

Chironex fleckeri (Australian box jellyfish) stings can cause acute cardiovascular collapse and death. We developed methods to recover venom with high specific activity, and evaluated the effects of both total venom and constituent porins at doses equivalent to lethal envenomation. Marked potassium release occurred within 5 min and hemolysis within 20 min in human red blood cells (RBC) exposed to venom or purified venom porin. Electron microscopy revealed abundant ?12-nm transmembrane pores in RBC exposed to purified venom porins. C57BL/6 mice injected with venom showed rapid decline in ejection fraction with progression to electromechanical dissociation and electrocardiographic findings consistent with acute hyperkalemia. Recognizing that porin assembly can be inhibited by zinc, we found that zinc gluconate inhibited potassium efflux from RBC exposed to total venom or purified porin, and prolonged survival time in mice following venom injection. These findings suggest that hyperkalemia is the critical event following Chironex fleckeri envenomation and that rapid administration of zinc could be life saving in human sting victims. PMID:23251508

Yanagihara, Angel A.; Shohet, Ralph V.

2012-01-01

20

The cellular eye lens and crystallins of cubomedusan jellyfish  

Microsoft Academic Search

The ultrastructure and major soluble proteins of the transparent eye lens of two cubomedusan jellyfish,Tripedalia cystophora andCarybdea marsupialis, have been examined. Each species has two complex eyes (one large and one small) on four sensory structures called rhopalia. The lenses consist of closely spaced cells with few organelles. The lens is situated next to the retina, with only an acellular

Joram Piatigorsky; Joseph Horwitz; Toichiro Kuwabara; Charles E. Cutress

1989-01-01

21

Jellyfish Party: Blowing Soap Bubbles in Mixed Reality Space  

Microsoft Academic Search

This paper describes a mixed reality installation named Jellyfish Party, for enjoying playing with soap bubbles. A special feature of this installation is the use of a spirometer sensor to measure the amount and speed of expelled air used to blow virtual soap bubbles.

Yasuhiro Okuno; Hiroyuki Kakuta; Tomohiko Takayama; Kazuhiro Asai

2003-01-01

22

Medical aspects of jellyfish envenomation: pathogenesis, case reporting and therapy  

Microsoft Academic Search

With larger human population numbers and their need for recreation, contact between humans and jellyfish is increasing. The pathogenesis of cnidarian stings is discussed here and some of the factors influencing the variability in adverse reactions they produce are mentioned. The pharmakinetics of venom delivery determines the organ site of damage and the extent of abnormality. Since venoms can injure

Joseph W. Burnett

2001-01-01

23

Project Jelly-Fish: B.R.N.O. Observations of Semiregular Variable Stars  

NASA Astrophysics Data System (ADS)

Brno Regional Network of Observers (BRNO) is a group which prefers to observe eclipsing binary stars. A team called the Jelly-Fish has been formed within BRNO for the purpose of observing variable stars other than eclipsing binaries. The observations by Jelly-Fish members are predominantly visual; CCD observing has started only recently and such observations are not yet included in our statistics. Jelly-Fish has about twenty members at this moment. This paper presents preliminary results based on Jelly-Fish observations of S Camelopardalis, AU Camelopardalis, WZ Cassiopeiae, RS Cygni, T Persei, RU Persei, and R Ursae Minoris.

Hajek, P.

2006-06-01

24

Biomass of Scyphozoan Jellyfish, and Its Spatial Association with 0-Group Fish in the Barents Sea  

PubMed Central

An 0-group fish survey is conducted annually in the Barents Sea in order to estimate fish population abundance. Data on jellyfish by-catch have been recorded since 1980, although this dataset has never been analysed. In recent years, however, the ecological importance of jellyfish medusae has become widely recognized. In this paper the biomass of jellyfish (medusae) in 0–60 m depths is calculated for the period 1980–2010. During this period the climate changed from cold to warm, and changes in zooplankton and fish distribution and abundance were observed. This paper discusses the less well known ecosystem component; jellyfish medusae within the Phylum Cnidaria, and their spatial and temporal variation. The long term average was ca. 9×108 kg, with some years showing biomasses in excess of 5×109 kg. The biomasses were low during 1980s, increased during 1990s, and were highest in early 2000s with a subsequent decline. The bulk of the jellyfish were observed in the central parts of the Barents Sea, which is a core area for most 0-group fishes. Jellyfish were associated with haddock in the western area, with haddock and herring in the central and coastal area, and with capelin in the northern area of the Barents Sea. The jellyfish were present in the temperature interval 1°Cjellyfish occurring between 4.0–7.0°C. It seems that the ongoing warming trend may be favourable for Barents Sea jellyfish medusae; however their biomass has showed a recent moderate decline during years with record high temperatures in the Barents Sea. Jellyfish are undoubtedly an important component of the Barents Sea ecosystem, and the data presented here represent the best summary of jellyfish biomass and distribution yet published for the region. PMID:22457732

Eriksen, Elena; Prozorkevich, Dmitry; Trofimov, Aleksandr; Howell, Daniel

2012-01-01

25

Biomass of scyphozoan jellyfish, and its spatial association with 0-group fish in the Barents Sea.  

PubMed

An 0-group fish survey is conducted annually in the Barents Sea in order to estimate fish population abundance. Data on jellyfish by-catch have been recorded since 1980, although this dataset has never been analysed. In recent years, however, the ecological importance of jellyfish medusae has become widely recognized. In this paper the biomass of jellyfish (medusae) in 0-60 m depths is calculated for the period 1980-2010. During this period the climate changed from cold to warm, and changes in zooplankton and fish distribution and abundance were observed. This paper discusses the less well known ecosystem component; jellyfish medusae within the Phylum Cnidaria, and their spatial and temporal variation. The long term average was ca. 9×10? kg, with some years showing biomasses in excess of 5×10? kg. The biomasses were low during 1980s, increased during 1990s, and were highest in early 2000s with a subsequent decline. The bulk of the jellyfish were observed in the central parts of the Barents Sea, which is a core area for most 0-group fishes. Jellyfish were associated with haddock in the western area, with haddock and herring in the central and coastal area, and with capelin in the northern area of the Barents Sea. The jellyfish were present in the temperature interval 1°Cjellyfish occurring between 4.0-7.0°C. It seems that the ongoing warming trend may be favourable for Barents Sea jellyfish medusae; however their biomass has showed a recent moderate decline during years with record high temperatures in the Barents Sea. Jellyfish are undoubtedly an important component of the Barents Sea ecosystem, and the data presented here represent the best summary of jellyfish biomass and distribution yet published for the region. PMID:22457732

Eriksen, Elena; Prozorkevich, Dmitry; Trofimov, Aleksandr; Howell, Daniel

2012-01-01

26

Jellyfish swarms, tourists, and the Christ-child  

Microsoft Academic Search

One of the most remarkable sights in the Western Pacific is a perennial swarm of 1.5 million golden medusae (Mastigias sp.) crowded into a land-locked marine lake in Palau, Micronesia. This 'Jellyfish Lake' became a popular off-gassing stopover for SCUBA divers and a destination in its own right for non-diving tourists in the mid-1980s. Since then, tourism in Palau has

Mike N Dawson; Laura E. Martin; Lolita K. Penland

2001-01-01

27

Hemolytic venoms from marine cnidarian jellyfish - an overview  

PubMed Central

Cnidarian jellyfish are viewed as an emergent problem in several coastal zones throughout the world. Recurrent outbreaks pose a serious threat to tourists and bathers, as well as to sea-workers, involving health and economical aspects. As a rule, cnidarian stinging as a consequence of nematocyst firing induces merely local symptoms but cardiovascular or neurological complications can also occur. Hemolysis is a frequent effect of cnidarian stinging; this dangerous condition is known to be caused by several venoms and can sometimes be lethal. At present, the bulk of data concerning hemolytic cnidarian venoms comes from the study of benthic species, such as sea anemones and soft corals, but hemolytic factors were found in venoms of several siphonophore, cubozoan and scyphozoan jellyfish, which are mainly involved in the envenomation of bathers and sea-workers. Therefore, the aim of this paper is to review the scientific literature concerning the hemolytic venoms from cnidarian jellyfish taking into consideration their importance in human pathology as well as health implications and possible therapeutic measures. PMID:25386336

Mariottini, Gian Luigi

2014-01-01

28

Modeling and control of a jellyfish-inspired AUV  

NASA Astrophysics Data System (ADS)

Current autonomous underwater vehicle (AUV) designs have a serious deficiency in autonomy time due to its ballistic type of construction: a cylindrical body propelled by a rear engine. This type of design does not take complete advantage of the fluid that has to be displaced to move the vehicle forward, reducing the overall system efficiency and consequently its operation time. In order to overcome this limitation, research has focused on understanding of the propulsive mechanisms employed by the natural organisms. Jellyfish is one of the simplest and most relevant model systems as it exhibits one of the lowest cost-of-transport among all the known creatures. The learning and implementation of jellyfish-inspired vehicle design requires an evaluation of the current mathematical modeling approaches in order to adequately describe the dynamics of such a vehicle. This paper develops a time-varying rigid body model for the kinematics and dynamics of an AUV based on jellyfish rowing propulsion. A nonlinear sliding mode controller is also proposed to drive the system.

Faria, Cassio T.; Priya, Shashank; Inman, Daniel J.

2013-04-01

29

The energy density of jellyfish: Estimates from bomb-calorimetry and proximate-composition  

E-print Network

The energy density of jellyfish: Estimates from bomb-calorimetry and proximate-composition Thomas K scyphozoan jellyfish (Cyanea capillata, Rhizostoma octopus and Chrysaora hysoscella). First, bomb-calorimetry). These proximate data were subsequently converted to energy densities. The two techniques (bomb- calorimetry

Hays, Graeme

30

Interannual variability in abundance of North Sea jellyfish and links to the North Atlantic Oscillation  

Microsoft Academic Search

Pronounced interannual variability in the abundance of medusae of the jellyfish species Aurelia aurita, Cyanea lamarckii, and Cyanea capillata (Phylum Cnidaria, Class Scyphozoa) in the North Sea was evident in data arising from the International Council for the Exploration of the Seas International 0-group Gadoid Surveys between 1971 and 1986. Possible climatic forcing of jellyfish abundance, via the North Atlantic

Christopher P. Lynam; Stephen J. Hay; Andrew S. Brierley

2004-01-01

31

JELLYFISH AGGREGATIONS AND LEATHERBACK TURTLE FORAGING PATTERNS IN A TEMPERATE COASTAL ENVIRONMENT  

Microsoft Academic Search

Leatherback turtles (Dermochelys coriacea) are obligate predators of gelatinous zooplankton. However, the spatial relationship between predator and prey remains poorly understood beyond sporadic and localized reports. To examine how jellyfish (Phylum Cnidaria: Orders Semaeostomeae and Rhizostomeae) might drive the broad-scale distribution of this wide ranging species, we employed aerial surveys to map jellyfish throughout a temperate coastal shelf area bordering

Jonathan D. R. Houghton; Thomas K. Doyle; Mark W. Wilson; John Davenport; Graeme C. Hays

2006-01-01

32

Signatures of active and passive optimized Lévy searching in jellyfish.  

PubMed

Some of the strongest empirical support for Lévy search theory has come from telemetry data for the dive patterns of marine predators (sharks, bony fishes, sea turtles and penguins). The dive patterns of the unusually large jellyfish Rhizostoma octopus do, however, sit outside of current Lévy search theory which predicts that a single search strategy is optimal. When searching the water column, the movement patterns of these jellyfish change over time. Movement bouts can be approximated by a variety of Lévy and Brownian (exponential) walks. The adaptive value of this variation is not known. On some occasions movement pattern data are consistent with the jellyfish prospecting away from a preferred depth, not finding an improvement in conditions elsewhere and so returning to their original depth. This 'bounce' behaviour also sits outside of current Lévy walk search theory. Here, it is shown that the jellyfish movement patterns are consistent with their using optimized 'fast simulated annealing'--a novel kind of Lévy walk search pattern--to locate the maximum prey concentration in the water column and/or to locate the strongest of many olfactory trails emanating from more distant prey. Fast simulated annealing is a powerful stochastic search algorithm for locating a global maximum that is hidden among many poorer local maxima in a large search space. This new finding shows that the notion of active optimized Lévy walk searching is not limited to the search for randomly and sparsely distributed resources, as previously thought, but can be extended to embrace other scenarios, including that of the jellyfish R. octopus. In the presence of convective currents, it could become energetically favourable to search the water column by riding the convective currents. Here, it is shown that these passive movements can be represented accurately by Lévy walks of the type occasionally seen in R. octopus. This result vividly illustrates that Lévy walks are not necessarily the result of selection pressures for advantageous searching behaviour but can instead arise freely and naturally from simple processes. It also shows that the family of Lévy walkers is vastly larger than previously thought and includes spores, pollens, seeds and minute wingless arthropods that on warm days disperse passively within the atmospheric boundary layer. PMID:25100323

Reynolds, Andy M

2014-10-01

33

A tissue-engineered jellyfish with biomimetic propulsion.  

PubMed

Reverse engineering of biological form and function requires hierarchical design over several orders of space and time. Recent advances in the mechanistic understanding of biosynthetic compound materials, computer-aided design approaches in molecular synthetic biology 4,5 and traditional soft robotics, and increasing aptitude in generating structural and chemical micro environments that promote cellular self-organization have enhanced the ability to recapitulate such hierarchical architecture in engineered biological systems. Here we combined these capabilities in a systematic design strategy to reverse engineer a muscular pump. We report the construction of a freely swimming jellyfish from chemically dissociated rat tissue and silicone polymer as a proof of concept. The constructs, termed 'medusoids', were designed with computer simulations and experiments to match key determinants of jellyfish propulsion and feeding performance by quantitatively mimicking structural design, stroke kinematics and animal-fluid interactions. The combination of the engineering design algorithm with quantitative benchmarks of physiological performance suggests that our strategy is broadly applicable to reverse engineering of muscular organs or simple life forms that pump to survive. PMID:22820316

Nawroth, Janna C; Lee, Hyungsuk; Feinberg, Adam W; Ripplinger, Crystal M; McCain, Megan L; Grosberg, Anna; Dabiri, John O; Parker, Kevin Kit

2012-08-01

34

A tissue-engineered jellyfish with biomimetic propulsion  

PubMed Central

Reverse engineering of biological form and function requires hierarchical design over several orders of space and time. Recent advances in the mechanistic understanding of biosynthetic compound materials1–3, computer-aided design approaches in molecular synthetic biology4,5 and traditional soft robotics6,7, and increasing aptitude in generating structural and chemical microenvironments that promote cellular self-organization8–10 have enhanced the ability to recapitulate such hierarchical architecture in engineered biological systems. Here we combined these capabilities in a systematic design strategy to reverse engineer a muscular pump. We report the construction of a freely swimming jellyfish from chemically dissociated rat tissue and silicone polymer as a proof of concept. The constructs, termed ‘medusoids’, were designed with computer simulations and experiments to match key determinants of jellyfish propulsion and feeding performance by quantitatively mimicking structural design, stroke kinematics and animal-fluid interactions. The combination of the engineering design algorithm with quantitative benchmarks of physiological performance suggests that our strategy is broadly applicable to reverse engineering of muscular organs or simple life forms that pump to survive. PMID:22820316

Nawroth, Janna C; Lee, Hyungsuk; Feinberg, Adam W; Ripplinger, Crystal M; McCain, Megan L; Grosberg, Anna; Dabiri, John O; Parker, Kevin Kit

2014-01-01

35

Is sleep's 'supreme mystery' unraveling? An evolutionary analysis of sleep encounters no mystery; nor does life's earliest sleep, recently discovered in jellyfish.  

E-print Network

captivity with food provided, C. fleckeri sleeps little orof facultative sleep, dependent on lifestyle. The foodfood without much need to engage in high-speed activity, there also may be little or no need for sleep.

Kavanau, Julian L.

2006-01-01

36

Influence of decomposing jellyfish on the sediment oxygen demand and nutrient dynamics  

Microsoft Academic Search

Jellyfish populations can grow rapidly to attain large biomasses and therefore can represent significant stocks of carbon\\u000a and nitrogen in the ecosystem. Blooms are also generally short-lived, lasting for just weeks or months, after which time the\\u000a population can decline rapidly, sink to the bottom and decompose. The influence of decomposing jellyfish (Catostylus mosaicus, Scyphozoa) on benthic dissolved oxygen and

Elizabeth Jane West; David Thomas Welsh; Kylie Anne Pitt

2009-01-01

37

Influence of decomposing jellyfish on the sediment oxygen demand and nutrient dynamics  

Microsoft Academic Search

Jellyfish populations can grow rapidly to attain large biomasses and therefore can represent significant stocks of carbon\\u000a and nitrogen in the ecosystem. Blooms are also generally short-lived, lasting for just weeks or months, after which time the\\u000a population can decline rapidly, sink to the bottom and decompose. The influence of decomposing jellyfish (Catostylus mosaicus, Scyphozoa) on benthic dissolved oxygen and

Elizabeth Jane West; David Thomas Welsh; Kylie Anne Pitt

38

Study on effect of jellyfish collagen hydrolysate on anti-fatigue and anti-oxidation  

Microsoft Academic Search

Many bioactive peptides possess specific biological properties that make potential ingredients of health-promoting foods. Jellyfish, which is rich in collagen, has high nutritious and medicinal value. In this study, jellyfish collagen hydrolysate (JCH) were produced. The in vivo anti-fatigue activity and in vivo antioxidant activity of JCH were determined, respectively. Climbing endurance tests of mice were carried out after 6w

Jin-Feng Ding; Yan-Yan Li; Jia-Jie Xu; Xiu-Rong Su; Xiang Gao; Fu-Peng Yue

2011-01-01

39

A jellyfish-like swimming mini-robot actuated by an electromagnetic actuation system  

NASA Astrophysics Data System (ADS)

Among the various kinds of actuations for biomimetic robots, the electromagnetic actuation (EMA) method has been regarded as the one with the most potential. This paper proposes a jellyfish-like swimming mini-robot actuated by an EMA system in three-dimensional (3D) space. The jellyfish-like mini-robot has four flexible fins, each of which is equipped with a permanent magnet for electromagnetic actuation; the robot’s body is 17 mm long and 0.5 mm thick. Our EMA system was able to generate a uniform magnetic field in a desired direction in 3D space, which could bend the fins of the jellyfish-like mini-robot. Therefore, a cyclic change in the uniform magnetic field, in the EMA system, would synchronize the fluctuation of the fins and could generate a propulsion force for the robot, in the desired direction. In order to maximize the propulsion force of the jellyfish-like mini-robot, the waveform and frequency of the input current in the EMA system are optimized. Consequently, our jellyfish-like mini-robot was able to generate maximum propulsion force when a square waveform input current (13 A magnitude and 10 Hz frequency) was applied to the EMA system. Finally, the jellyfish-like mini-robot with the EMA system was able to perform various 3D swimming motions.

Ko, Youngho; Na, Sungyoung; Lee, Youngwoo; Cha, Kyoungrae; Ko, Seong Young; Park, Jongoh; Park, Sukho

2012-05-01

40

Extract from the Zooxanthellate Jellyfish Cotylorhiza tuberculata Modulates Gap Junction Intercellular Communication in Human Cell Cultures  

PubMed Central

On a global scale, jellyfish populations in coastal marine ecosystems exhibit increasing trends of abundance. High-density outbreaks may directly or indirectly affect human economical and recreational activities, as well as public health. As the interest in biology of marine jellyfish grows, a number of jellyfish metabolites with healthy potential, such as anticancer or antioxidant activities, is increasingly reported. In this study, the Mediterranean “fried egg jellyfish” Cotylorhiza tuberculata (Macri, 1778) has been targeted in the search forputative valuable bioactive compounds. A medusa extract was obtained, fractionated, characterized by HPLC, GC-MS and SDS-PAGE and assayed for its biological activity on breast cancer cells (MCF-7) and human epidermal keratinocytes (HEKa). The composition of the jellyfish extract included photosynthetic pigments, valuable ?-3 and ?-6 fatty acids, and polypeptides derived either from jellyfish tissues and their algal symbionts. Extract fractions showed antioxidant activity and the ability to affect cell viability and intercellular communication mediated by gap junctions (GJIC) differentially in MCF-7and HEKa cells. A significantly higher cytotoxicity and GJIC enhancement in MCF-7 compared to HEKa cells was recorded. A putative action mechanism for the anticancer bioactivity through the modulation of GJIC has been hypothesized and its nutraceutical and pharmaceutical potential was discussed. PMID:23697954

Leone, Antonella; Lecci, Raffaella Marina; Durante, Miriana; Piraino, Stefano

2013-01-01

41

Role of Thyroxine in Space-Developed Jellyfish  

NASA Technical Reports Server (NTRS)

The Aurelia Metamorphosis Test System was previously used to determine the effects of the space environment on the development and behavior of tiny (1-2 mm) jellyfish ephyrae during the SLS-1 and IML-2 missions. Results from the SLS-1 experiment included the discovery that statolith numbers were significantly reduced in Earth-formed ephyrae flown for nine days in space as compared with ground-based controls. In addition, upon return to Earth, six times more ephyrae which had developed in space than those developed on Earth had pulsing abnormalities, indicating that either these animals did not form their neuromuscular structures normally while in space or they were unable to adapt to the Ig environment upon return to Earth. The metamorphosis process, which enables the formation of ephyrae from polyps is influenced by a hormone, Jf-T4 Oellyfish thyroxine) which is synthesized following iodine administration. Two groups of polyps in space, however, formed ephyrae without iodine administration indicating that Jf-T4 synthesis, utilization, or excretion was different in. the ephyrae. Increased synthesis or build-up in the media of the hormone may also be linked to the increased demineralization of statoliths found in space-exposed ephyrae. In previous experiments, we found that externally administered thyroxine causes increased demineralization of statoliths on Earth. Abnormal pulsina in ephyrae following return to Earth during the SLS-1 mission may also be traced to increased Jf-T4 levels. Thyroxine is known to be important to the normal development and function of the nervous system, heart, and skeletal muscles in higher animals. For this third Jellyfish-in-Space experiment, we proposed to quantitate the levels of Jf- T4 and of T4 receptors in space-developed ephyrae and media and to compare these levels with those of animals developing and at Ig in space and on Earth. We expected to be able to determine whether Jf-T4 synthesis and/or secretion is different in space-flownjellyfish than in controls and to determine which cells (nerve, muscle, lithocytes, etc.)may have enhanced Jf-T4 levels. However, NASA deselected this experiment in August, 1997.

Spangenberg, Dorothy B.

1997-01-01

42

Effects of anthropogenic disturbance on the abundance and size of epibenthic jellyfish Cassiopea spp.  

PubMed

Jellyfish blooms in pelagic systems appear to be increasing on a global scale because of anthropogenic impacts, but much less is known about the link between human activities and epibenthic jellyfish abundance. The aim of this study was to investigate whether the epibenthic jellyfish, Cassiopea spp., were found in greater abundance, and attained larger sizes, in coastal habitats adjacent to high human population densities compared to sites adjacent to uninhabited areas on Abaco Island, Bahamas. Cassiopea spp. were found to be significantly more dense and larger in areas with high human population densities. Ambient nutrient levels and nutrient content of seagrass were elevated in high human population density sites, and may be one mechanism driving higher abundance and size of Cassiopea spp. Cassiopea spp. may have important effects on community structure and ecosystem function in critical coastal ecosystems (e.g., seagrass beds), and their impacts warrant further study. PMID:21486672

Stoner, Elizabeth W; Layman, Craig A; Yeager, Lauren A; Hassett, Heather M

2011-05-01

43

Stable hovering of a jellyfish-like flying machine.  

PubMed

Ornithopters, or flapping-wing aircraft, offer an alternative to helicopters in achieving manoeuvrability at small scales, although stabilizing such aerial vehicles remains a key challenge. Here, we present a hovering machine that achieves self-righting flight using flapping wings alone, without relying on additional aerodynamic surfaces and without feedback control. We design, construct and test-fly a prototype that opens and closes four wings, resembling the motions of swimming jellyfish more so than any insect or bird. Measurements of lift show the benefits of wing flexing and the importance of selecting a wing size appropriate to the motor. Furthermore, we use high-speed video and motion tracking to show that the body orientation is stable during ascending, forward and hovering flight modes. Our experimental measurements are used to inform an aerodynamic model of stability that reveals the importance of centre-of-mass location and the coupling of body translation and rotation. These results show the promise of flapping-flight strategies beyond those that directly mimic the wing motions of flying animals. PMID:24430122

Ristroph, Leif; Childress, Stephen

2014-03-01

44

Stable hovering of a jellyfish-like flying machine  

PubMed Central

Ornithopters, or flapping-wing aircraft, offer an alternative to helicopters in achieving manoeuvrability at small scales, although stabilizing such aerial vehicles remains a key challenge. Here, we present a hovering machine that achieves self-righting flight using flapping wings alone, without relying on additional aerodynamic surfaces and without feedback control. We design, construct and test-fly a prototype that opens and closes four wings, resembling the motions of swimming jellyfish more so than any insect or bird. Measurements of lift show the benefits of wing flexing and the importance of selecting a wing size appropriate to the motor. Furthermore, we use high-speed video and motion tracking to show that the body orientation is stable during ascending, forward and hovering flight modes. Our experimental measurements are used to inform an aerodynamic model of stability that reveals the importance of centre-of-mass location and the coupling of body translation and rotation. These results show the promise of flapping-flight strategies beyond those that directly mimic the wing motions of flying animals. PMID:24430122

Ristroph, Leif; Childress, Stephen

2014-01-01

45

Rapid scavenging of jellyfish carcasses reveals the importance of gelatinous material to deep-sea food webs.  

PubMed

Jellyfish blooms are common in many oceans, and anthropogenic changes appear to have increased their magnitude in some regions. Although mass falls of jellyfish carcasses have been observed recently at the deep seafloor, the dense necrophage aggregations and rapid consumption rates typical for vertebrate carrion have not been documented. This has led to a paradigm of limited energy transfer to higher trophic levels at jelly falls relative to vertebrate organic falls. We show from baited camera deployments in the Norwegian deep sea that dense aggregations of deep-sea scavengers (more than 1000 animals at peak densities) can rapidly form at jellyfish baits and consume entire jellyfish carcasses in 2.5 h. We also show that scavenging rates on jellyfish are not significantly different from fish carrion of similar mass, and reveal that scavenging communities typical for the NE Atlantic bathyal zone, including the Atlantic hagfish, galatheid crabs, decapod shrimp and lyssianasid amphipods, consume both types of carcasses. These rapid jellyfish carrion consumption rates suggest that the contribution of gelatinous material to organic fluxes may be seriously underestimated in some regions, because jelly falls may disappear much more rapidly than previously thought. Our results also demonstrate that the energy contained in gelatinous carrion can be efficiently incorporated into large numbers of deep-sea scavengers and food webs, lessening the expected impacts (e.g. smothering of the seafloor) of enhanced jellyfish production on deep-sea ecosystems and pelagic-benthic coupling. PMID:25320167

Sweetman, Andrew K; Smith, Craig R; Dale, Trine; Jones, Daniel O B

2014-12-01

46

A bio-inspired bell kinematics design of a jellyfish robot using ionic polymer metal composites actuators  

NASA Astrophysics Data System (ADS)

This paper presents the re-creation of the bell deformation cycle of the Aequorea victoria jellyfish. It focuses on the design, fabrication, and characterization of the bio-inspired bell kinematics of an IPMC actuated robotic jellyfish. The shape and bell kinematics of this underwater vehicle are based on the Aequorea victoria jellyfish. This medusa is chosen as a model system based on a comparative bell kinematics study that is conducted among different jellyfish species. Aequorea victoria is known by its low swimming frequency, small bell deformation, and high Froude efficiency (95%). Different methods of implementing the actuators underneath the bell with smaller IPMC actuators are investigated to replicate the natural jellyfish's bell deformation. Results demonstrates that proper placement of the IPMC actuators results in bell configuration that more accurately represents the deformation properties of the natural jellyfish. Smaller IPMC actuators are used to achieve the desired deformation and thus the power consumption is reduced by 70% compared to previous generations. A biomimetic jellyfish robot prototype is built, and its ability to swim and produce thrust with smaller IPMC actuators is shown. The robot swam with four actuators swam at an average speed 0.77 mm/s and consumed 0.7 W. When eight actuators were used the average speed increased to 1.5 mm/s with a power consumption of 1.14 W.

Najem, Joseph; Leo, Donald J.

2012-04-01

47

Gill Damage to Atlantic Salmon (Salmo salar) Caused by the Common Jellyfish (Aurelia aurita) under Experimental Challenge  

PubMed Central

Background Over recent decades jellyfish have caused fish kill events and recurrent gill problems in marine-farmed salmonids. Common jellyfish (Aurelia spp.) are among the most cosmopolitan jellyfish species in the oceans, with populations increasing in many coastal areas. The negative interaction between jellyfish and fish in aquaculture remains a poorly studied area of science. Thus, a recent fish mortality event in Ireland, involving Aurelia aurita, spurred an investigation into the effects of this jellyfish on marine-farmed salmon. Methodology/Principal Findings To address the in vivo impact of the common jellyfish (A. aurita) on salmonids, we exposed Atlantic salmon (Salmo salar) smolts to macerated A. aurita for 10 hrs under experimental challenge. Gill tissues of control and experimental treatment groups were scored with a system that rated the damage between 0 and 21 using a range of primary and secondary parameters. Our results revealed that A. aurita rapidly and extensively damaged the gills of S. salar, with the pathogenesis of the disorder progressing even after the jellyfish were removed. After only 2 hrs of exposure, significant multi-focal damage to gill tissues was apparent. The nature and extent of the damage increased up to 48 hrs from the start of the challenge. Although the gills remained extensively damaged at 3 wks from the start of the challenge trial, shortening of the gill lamellae and organisation of the cells indicated an attempt to repair the damage suffered. Conclusions Our findings clearly demonstrate that A. aurita can cause severe gill problems in marine-farmed fish. With aquaculture predicted to expand worldwide and evidence suggesting that jellyfish populations are increasing in some areas, this threat to aquaculture is of rising concern as significant losses due to jellyfish could be expected to increase in the future. PMID:21490977

Baxter, Emily J.; Sturt, Michael M.; Ruane, Neil M.; Doyle, Thomas K.; McAllen, Rob; Harman, Luke; Rodger, Hamish D.

2011-01-01

48

Central circuitry in the jellyfish Aglantha. I: The relay system  

PubMed

1. The relay system is an interneuronal pathway in the margin of the jellyfish Aglantha digitale. It excites a second interneuronal pathway, the carrier system, and is itself excited by pacemaker neurones concerned with slow swimming. It also excites a slow conduction pathway in the tentacles causing graded, tonic contractions of all the tentacles during slow swimming. 2. The pacemakers, the carrier system and the relay system all contribute to the production of excitatory postsynaptic potentials (EPSPs) in a giant axon that runs in the outer nerve ring (ring giant axon). These EPSPs may cause the latter to spike during slow swimming. If it does so, it will fire tentacle giant axons, producing twitch contractions of the tentacles. Such contractions probably help to contract the tentacles rapidly at the start of slow swimming. This is an unusual case of a giant axon that normally mediates escape behaviour being appropriated for use during a non-escape activity. 3. The relay system can conduct impulses on its own but their conduction velocity is greatly increased when preceded by either pacemaker or ring giant spikes. This phenomenon, termed the 'piggyback effect', may be due to extracellular field effects rather than to actions mediated by chemical or electrical synapses. 4. Recordings from the epithelial cells that ensheath the ring giant and outer nerve ring neurones show miniature synaptic potentials and other events that seem to reflect events in the nervous system, but no functions can be assigned to them. 5. There is no obvious counterpart to the relay system in medusae lacking escape circuitry. PMID:9320176

Mackie; Meech

1995-01-01

49

Jellyfish populations in the Mediterranean Sea Lucas BROTz* and Daniel PAULy  

E-print Network

, eutrophication, overfishing, bottom-trawling, mariculture, and increased coastal development. Similar trends the Mediterranean Sea. Some groups show differing or opposite trends, and these trends may vary widely depending, several conspicuous groups of jellyfish appear to exhibit sustained increases in the Mediter- ranean Sea

Pauly, Daniel

50

An unusual blue mesogleal protein from the mangrove jellyfish Cassiopea xamachana  

Microsoft Academic Search

The jellyfish Cassiopea xamachana often contains a blue pigment diffused within the acellular portion of its masoglea. In the bell, both the pigment and endosymbiotic zooxanthellae are concentrated immediately beneath the ex-and subumbrellar epithelia. Chromatographic and polyacrylamide gel electrophoretic techniques demonstrate that the pigment is a highly polymeric glycoprotein (mol. wt>106 daltons) comprised of two subunits with molecular weights of

R. S. Blanquet; M. A. Phelan

1987-01-01

51

DalTREC 2005 QA System Jellyfish: Mark-and-Match Approach to Question Answering  

E-print Network

DalTREC 2005 QA System Jellyfish: Mark-and-Match Approach to Question Answering Tony Abou-Assaleh-up deterministic parsing technique. For example, the rewriting in which " " is replaced with "z>" corresponds to the context- free rule S NP VP. The value z is obtained by decoding x and y, concatenating

Keselj, Vlado

52

Passive energy recapture in jellyfish contributes to propulsive advantage over other metazoans  

PubMed Central

Gelatinous zooplankton populations are well known for their ability to take over perturbed ecosystems. The ability of these animals to outcompete and functionally replace fish that exhibit an effective visual predatory mode is counterintuitive because jellyfish are described as inefficient swimmers that must rely on direct contact with prey to feed. We show that jellyfish exhibit a unique mechanism of passive energy recapture, which is exploited to allow them to travel 30% further each swimming cycle, thereby reducing metabolic energy demand by swimming muscles. By accounting for large interspecific differences in net metabolic rates, we demonstrate, contrary to prevailing views, that the jellyfish (Aurelia aurita) is one of the most energetically efficient propulsors on the planet, exhibiting a cost of transport (joules per kilogram per meter) lower than other metazoans. We estimate that reduced metabolic demand by passive energy recapture improves the cost of transport by 48%, allowing jellyfish to achieve the large sizes required for sufficient prey encounters. Pressure calculations, using both computational fluid dynamics and a newly developed method from empirical velocity field measurements, demonstrate that this extra thrust results from positive pressure created by a vortex ring underneath the bell during the refilling phase of swimming. These results demonstrate a physical basis for the ecological success of medusan swimmers despite their simple body plan. Results from this study also have implications for bioinspired design, where low-energy propulsion is required. PMID:24101461

Gemmell, Brad J.; Costello, John H.; Colin, Sean P.; Stewart, Colin J.; Dabiri, John O.; Tafti, Danesh; Priya, Shashank

2013-01-01

53

Passive energy recapture in jellyfish contributes to propulsive advantage over other metazoans.  

PubMed

Gelatinous zooplankton populations are well known for their ability to take over perturbed ecosystems. The ability of these animals to outcompete and functionally replace fish that exhibit an effective visual predatory mode is counterintuitive because jellyfish are described as inefficient swimmers that must rely on direct contact with prey to feed. We show that jellyfish exhibit a unique mechanism of passive energy recapture, which is exploited to allow them to travel 30% further each swimming cycle, thereby reducing metabolic energy demand by swimming muscles. By accounting for large interspecific differences in net metabolic rates, we demonstrate, contrary to prevailing views, that the jellyfish (Aurelia aurita) is one of the most energetically efficient propulsors on the planet, exhibiting a cost of transport (joules per kilogram per meter) lower than other metazoans. We estimate that reduced metabolic demand by passive energy recapture improves the cost of transport by 48%, allowing jellyfish to achieve the large sizes required for sufficient prey encounters. Pressure calculations, using both computational fluid dynamics and a newly developed method from empirical velocity field measurements, demonstrate that this extra thrust results from positive pressure created by a vortex ring underneath the bell during the refilling phase of swimming. These results demonstrate a physical basis for the ecological success of medusan swimmers despite their simple body plan. Results from this study also have implications for bioinspired design, where low-energy propulsion is required. PMID:24101461

Gemmell, Brad J; Costello, John H; Colin, Sean P; Stewart, Colin J; Dabiri, John O; Tafti, Danesh; Priya, Shashank

2013-10-29

54

Flow patterns generated by oblate medusan jellyfish: field measurements and laboratory analyses  

Microsoft Academic Search

Flow patterns generated by medusan swimmers such as jellyfish are known to differ according the morphology of the various animal species. Oblate medusae have been previously observed to generate vortex ring structures during the propulsive cycle. Owing to the inherent physical coupling between locomotor and feeding structures in these animals, the dynamics of vortex ring formation must be robustly tuned

John O. Dabiri; Sean P. Colin; John H. Costello; Morteza Gharib

2005-01-01

55

Efficacy of Venom from Tentacle of Jellyfish Stomolophus meleagris (Nemopilema nomurai) against the Cotton Bollworm Helicoverpa armigera  

PubMed Central

Efficacy of venom from tentacle of jellyfish Stomolophus meleagris against the cotton bollworm Helicoverpa armigera was determined. Venom from tentacle of jellyfish Stomolophus meleagris could inhibit the growth of Helicoverpa armigera and the weight inhibiting rate of sample NFr-2 was 60.53%. Of the six samples, only NFr-2 had high insecticidal activity against Helicoverpa armigera and the corrected mortality recorded at 7?d was 74.23%. PMID:25162008

Yu, Huahua; Li, Rongfeng; Dong, Xiangli; Xing, Ronge; Liu, Song; Li, Pengcheng

2014-01-01

56

Efficacy of venom from tentacle of jellyfish Stomolophus meleagris (Nemopilema nomurai) against the cotton bollworm Helicoverpa armigera.  

PubMed

Efficacy of venom from tentacle of jellyfish Stomolophus meleagris against the cotton bollworm Helicoverpa armigera was determined. Venom from tentacle of jellyfish Stomolophus meleagris could inhibit the growth of Helicoverpa armigera and the weight inhibiting rate of sample NFr-2 was 60.53%. Of the six samples, only NFr-2 had high insecticidal activity against Helicoverpa armigera and the corrected mortality recorded at 7 d was 74.23%. PMID:25162008

Yu, Huahua; Li, Rongfeng; Dong, Xiangli; Xing, Ronge; Liu, Song; Li, Pengcheng

2014-01-01

57

Jellyfish prediction of occurrence from remote sensing data and a non-linear pattern recognition approach  

NASA Astrophysics Data System (ADS)

Impact of jellyfish in human activities has been increasingly reported worldwide in recent years. Segments such as tourism, water sports and leisure, fisheries and aquaculture are commonly damaged when facing blooms of gelatinous zooplankton. Hence the prediction of the appearance and disappearance of jellyfish in our coasts, which is not fully understood from its biological point of view, has been approached as a pattern recognition problem in the paper presented herein, where a set of potential ecological cues was selected to test their usefulness for prediction. Remote sensing data was used to describe environmental conditions that could support the occurrence of jellyfish blooms with the aim of capturing physical-biological interactions: forcing, coastal morphology, food availability, and water mass characteristics are some of the variables that seem to exert an effect on jellyfish accumulation on the shoreline, under specific spatial and temporal windows. A data-driven model based on computational intelligence techniques has been designed and implemented to predict jellyfish events on the beach area as a function of environmental conditions. Data from 2009 over the NW Mediterranean continental shelf have been used to train and test this prediction protocol. Standard level 2 products are used from MODIS (NASA OceanColor) and MERIS (ESA - FRS data). The procedure for designing the analysis system can be described as following. The aforementioned satellite data has been used as feature set for the performance evaluation. Ground truth has been extracted from visual observations by human agents on different beach sites along the Catalan area. After collecting the evaluation data set, the performance between different computational intelligence approaches have been compared. The outperforming one in terms of its generalization capability has been selected for prediction recall. Different tests have been conducted in order to assess the prediction capability of the resulting system in operational conditions. This includes taking into account several types of features with different distances in both the spatial and temporal domains with respect to prediction time and site. Moreover the generalization capability has been measured via cross-fold validation. The implementation and performance evaluation results are detailed in the present communication together with the feature extraction from satellite data. To the best of our knowledge the developed application constitutes the first implementation of an automate system for the prediction of jellyfish appearance founded on remote sensing technologies.

Albajes-Eizagirre, Anton; Romero, Laia; Soria-Frisch, Aureli; Vanhellemont, Quinten

2011-11-01

58

Jellyfish aggregations and leatherback turtle foraging patterns in a temperate coastal environment.  

PubMed

Leatherback turtles (Dermochelys coriacea) are obligate predators of gelatinous zooplankton. However, the spatial relationship between predator and prey remains poorly understood beyond sporadic and localized reports. To examine how jellyfish (Phylum Cnidaria: Orders Semaeostomeae and Rhizostomeae) might drive the broad-scale distribution of this wide ranging species, we employed aerial surveys to map jellyfish throughout a temperate coastal shelf area bordering the northeast Atlantic. Previously unknown, consistent aggregations of Rhizostoma octopus extending over tens of square kilometers were identified in distinct coastal "hotspots" during consecutive years (2003-2005). Examination of retrospective sightings data (>50 yr) suggested that 22.5% of leatherback distribution could be explained by these hotspots, with the inference that these coastal features may be sufficiently consistent in space and time to drive long-term foraging associations. PMID:16937635

Houghton, Jonathan D R; Doyle, Thomas K; Wilson, Mark W; Davenport, John; Hays, Graeme C

2006-08-01

59

Predation on fish larvae by moon jellyfish Aurelia aurita under low dissolved oxygen concentrations  

Microsoft Academic Search

Laboratory experiments were conducted to test the hypothesis that low dissolved oxygen concentrations have the potential to\\u000a enhance the predation rate on fish larvae by moon jellyfish Aurelia aurita which is increasing in abundance in the coastal waters of Japan. Larvae of the red sea bream Pagrus major in four size classes (2.9, 4.1, 6.2 and 8.6 mm in standard

Jun Shoji; Reiji Masuda; Yoh Yamashita; Masaru Tanaka

2005-01-01

60

Biomimetic jellyfish-inspired underwater vehicle actuated by ionic polymer metal composite actuators  

NASA Astrophysics Data System (ADS)

This paper presents the design, fabrication, and characterization of a biomimetic jellyfish robot that uses ionic polymer metal composites (IPMCs) as flexible actuators for propulsion. The shape and swimming style of this underwater vehicle are based on the Aequorea victoria jellyfish, which has an average swimming speed of 20 mm s-1 and which is known for its high swimming efficiency. The Aequorea victoria is chosen as a model system because both its bell morphology and kinematic properties match the mechanical properties of IPMC actuators. This medusa is characterized by its low swimming frequency, small bell deformation during the contraction phase, and high Froude efficiency. The critical components of the robot include the flexible bell that provides the overall shape and dimensions of the jellyfish, a central hub and a stage used to provide electrical connections and mechanical support to the actuators, eight distinct spars meant to keep the upper part of the bell stationary, and flexible IPMC actuators that extend radially from the central stage. The bell is fabricated from a commercially available heat-shrinkable polymer film to provide increased shape-holding ability and reduced weight. The IPMC actuators constructed for this study demonstrated peak-to-peak strains of ˜0.7% in water across a frequency range of 0.1-1.0 Hz. By tailoring the applied voltage waveform and the flexibility of the bell, the completed robotic jellyfish with four actuators swam at an average speed 0.77 mm s-1 and consumed 0.7 W. When eight actuators were used the average speed increased to 1.5 mm s-1 with a power consumption of 1.14 W.

Najem, Joseph; Sarles, Stephen A.; Akle, Barbar; Leo, Donald J.

2012-09-01

61

Optimization of antioxidant activity by response surface methodology in hydrolysates of jellyfish (Rhopilema esculentum) umbrella collagen*  

PubMed Central

To optimize the hydrolysis conditions to prepare hydrolysates of jellyfish umbrella collagen with the highest hydroxyl radical scavenging activity, collagen extracted from jellyfish umbrella was hydrolyzed with trypsin, and response surface methodology (RSM) was applied. The optimum conditions obtained from experiments were pH 7.75, temperature (T) 48.77 °C, and enzyme-to-substrate ratio ([E]/[S]) 3.50%. The analysis of variance in RSM showed that pH and [E]/[S] were important factors that significantly affected the process (P<0.05 and P<0.01, respectively). The hydrolysates of jellyfish umbrella collagen were fractionated by high performance liquid chromatography (HPLC), and three fractions (HF-1>3000 Da, 1000 Da

Zhuang, Yong-liang; Zhao, Xue; Li, Ba-fang

2009-01-01

62

A randomized paired comparison trial of cutaneous treatments for acute jellyfish (Carybdea alata) stings.  

PubMed

The objective of the study was to compare cutaneous treatments (heat, papain and vinegar) for acute jellyfish (Carybdea alata) stings. Healthy adult volunteer subjects received a single-tentacle jellyfish sting on each forearm. One forearm was treated with hot-water immersion (40-41 degrees C). This was compared with the other forearm, which was randomized to a comparison treatment of papain meat tenderizer or vinegar. Pain was measured at 0, 2, 4, 6, 8, 10, 15, and 20 minutes using a 10-cm visual analog scale (VAS). For 25 subject runs, the average VAS scores at t = 0 were 3.6 cm (hot water) and 3.7 cm (comparison treatment). At t = 4 minutes (2 minutes after treatment had started), the differences between hot-water and comparison group VAS scores were 2.1 cm versus 3.2 cm, respectively. The mean difference between hot-water and comparison treatments was 1.1 cm (95% confidence interval, 0.6 to 1.6). At t = 20 minutes (the end of the study period), the differences between hot-water and comparison group VAS scores were 0.2 cm versus 1.8 cm, respectively. The mean difference between hot-water and comparison treatments was 1.6 cm (95% confidence interval, 0.9 to 2.3). This study suggests that the most efficacious initial treatment for C alata jellyfish envenomation is hot-water immersion to the afflicted site. PMID:12442242

Nomura, Jason T; Sato, Renee L; Ahern, Reina M; Snow, Joanne L; Kuwaye, Todd T; Yamamoto, Loren G

2002-11-01

63

Neuropeptides trigger oocyte maturation and subsequent spawning in the hydrozoan jellyfish Cytaeis uchidae.  

PubMed

Oocyte maturation and subsequent spawning in hydrozoan jellyfish are generally triggered by light-dark cycles. To examine if the initiation of the maturation process after light stimulus is mediated by neurotransmitters, neuropeptides isolated originally from Hydra magnipapillata were applied to sexually mature female medusae of the hydrozoan jellyfish Cytaeis uchidae. Among the Hydra neuropeptides tested, Hym-53 (NPYPGLW-NH2 ), as well as a nonphysiological peptide, CGLWamide (CGLW-NH2 ), were most effective in inducing oocyte maturation and spawning. Hym-355 (FPQSFLPRG-NH2 ) also triggered these events, but the stimulatory effect was weaker. Since Hym-53-OH (NPYPGLW) and Hym-355-OH (FPQSFLPRG) had no effect, amidation at the C-terminus may be critical for the stimulatory activities of the peptides. Exposure to Hym-53 for 2 min was sufficient to trigger of oocyte maturation, and the spawned eggs were able to be fertilized and to develop normally. Transmission electron microscopy confirmed that bundles of axon-like structures that contain dense-core synaptic vesicles and microtubules are present in the ovarian ectodermal epithelium overlying the oocytes. In addition, immunohistological analyses revealed that some of the neurons in the ectodermal epithelium are GLWamide- and PRGamide-positive. These results suggest that a neuropeptide signal transduction pathway is involved in mediating the induction of oocyte maturation and spawning in this jellyfish. PMID:23341254

Takeda, Noriyo; Nakajima, Yoko; Koizumi, Osamu; Fujisawa, Toshitaka; Takahashi, Toshio; Matsumoto, Midori; Deguchi, Ryusaku

2013-03-01

64

THE JELLYFISH AURELIA AURITA (CNIDARIA: SCYPHOMEDUSAE): ITS LIFE HISTORY STRATEGY, MIGRATION ACTIVITY AND ITS IMPACT ON THE ZOOPLANKTON COMMUNITY OF SUEZ CANAL, EGYPT  

Microsoft Academic Search

Suez Canal is the main connecting link between the Red Sea in the south and the Mediterranean in the north. It crosses different lakes on its route from Port Said on the Mediterranean Sea to Port Suez on the Red Sea. Jellyfishes form a major part of the macro- plankton of the canal. The role of jellyfishes in general and

HAMED A. EL-SEREHY

65

Jellyfish as Prey: Frequency of Predation and Selective Foraging of Boops boops (Vertebrata, Actinopterygii) on the Mauve Stinger Pelagia noctiluca (Cnidaria, Scyphozoa)  

PubMed Central

In recent years, jellyfish blooms have attracted considerable scientific interest for their potential impacts on human activities and ecosystem functioning, with much attention paid to jellyfish as predators and to gelatinous biomass as a carbon sink. Other than qualitative data and observations, few studies have quantified direct predation of fish on jellyfish to clarify whether they may represent a seasonally abundant food source. Here we estimate predation frequency by the commercially valuable Mediterranean bogue, Boops boops on the mauve stinger jellyfish, Pelagia noctiluca, in the Strait of Messina (NE Sicily). A total of 1054 jellyfish were sampled throughout one year to quantify predation by B. boops from bite marks on partially eaten jellyfish and energy density of the jellyfish. Predation by B. boops in summer was almost twice that in winter, and they selectively fed according to medusa gender and body part. Calorimetric analysis and biochemical composition showed that female jellyfish gonads had significantly higher energy content than male gonads due to more lipids and that gonads had six-fold higher energy content than the somatic tissues due to higher lipid and protein concentrations. Energetically, jellyfish gonads represent a highly rewarding food source, largely available to B. boops throughout spring and summer. During the remainder of the year, when gonads were not very evident, fish predation switched towards less-selective foraging on the somatic gelatinous biomass. P. noctiluca, the most abundant jellyfish species in the Mediterranean Sea and a key planktonic predator, may represent not only a nuisance for human leisure activities and a source of mortality for fish eggs and larvae, but also an important resource for fish species of commercial value, such as B. boops. PMID:24727977

Fuentes, Veronica L.; Boero, Ferdinando; Guglielmo, Letterio; Purcell, Jennifer E.; Piraino, Stefano

2014-01-01

66

Effects of collagen and collagen hydrolysate from jellyfish umbrella on histological and immunity changes of mice photoaging.  

PubMed

Jellyfish collagen (JC) was extracted from jellyfish umbrella and hydrolyzed to prepare jellyfish collagen hydrolysate (JCH). The effects of JC and JCH on UV-induced skin damage of mice were evaluated by the skin moisture, microscopic analyses of skin and immunity indexes. The skin moisture analyses showed that moisture retention ability of UV-induced mice skin was increased by JC and JCH. Further histological analysis showed that JC and JCH could repair the endogenous collagen and elastin protein fibers, and could maintain the natural ratio of type I to type III collagen. The immunity indexes showed that JC and JCH play a role in enhancing immunity of photoaging mice in vivo. JCH showed much higher protective ability than JC. These results suggest that JCH as a potential novel antiphotoaging agent from natural resources. PMID:23344251

Fan, Jian; Zhuang, Yongliang; Li, Bafang

2013-01-01

67

Effects of Collagen and Collagen Hydrolysate from Jellyfish Umbrella on Histological and Immunity Changes of Mice Photoaging  

PubMed Central

Jellyfish collagen (JC) was extracted from jellyfish umbrella and hydrolyzed to prepare jellyfish collagen hydrolysate (JCH). The effects of JC and JCH on UV-induced skin damage of mice were evaluated by the skin moisture, microscopic analyses of skin and immunity indexes. The skin moisture analyses showed that moisture retention ability of UV-induced mice skin was increased by JC and JCH. Further histological analysis showed that JC and JCH could repair the endogenous collagen and elastin protein fibers, and could maintain the natural ratio of type I to type III collagen. The immunity indexes showed that JC and JCH play a role in enhancing immunity of photoaging mice in vivo. JCH showed much higher protective ability than JC. These results suggest that JCH as a potential novel antiphotoaging agent from natural resources. PMID:23344251

Fan, Jian; Zhuang, Yongliang; Li, Bafang

2013-01-01

68

Production of the Angiotensin-I-Converting Enzyme (ACE)Inhibitory Peptide from Hydrolysates of Jellyfish ( Rhopilema esculentum ) Collagen  

Microsoft Academic Search

Collagen extracted from jellyfish (Rhopilema esculentum) was hydrolyzed with alcalase to prepare the ACE-inhibitory peptide. The optimal hydrolyzing conditions were determined using\\u000a response surface methodology. The results showed that the optimal conditions were temperature of 52.7 °C, pH of 8.63 and enzyme-to-substrate\\u000a ratio (E\\/S) of 3.46%, and the ACE-inhibitory activity of the obtained hydrolysates could reach 81.7%. Jellyfish collagen peptide, UF3-B2,

Yongliang Zhuang; Liping Sun; Bafang Li

69

In depth analysis of the in vivo toxicity of venom from the jellyfish Stomolophus meleagris.  

PubMed

Jellyfish Stomolophus meleagris, a synonym of Nemopilema nomurai, which has often bloomed in the China Sea in recent years, is becoming an increasing threat to human health and life as a result of its strong toxicity. Each year, hundreds of thousands of people were stung, especially in the high season, and the victims suffered itch, edema, myalgia, dyspnea, hypotension, shock and even death. Here, we present the in-depth analysis of the in vivo toxicity of the venom from the jellyfish S. meleagris by using both an acute toxicological approach and pathological analyses. The venom showed an LD50 of approximately 2.92 ?g/g body weight in mice following an intravenous injection and caused renal glomerular swelling, renal vesicle stricture, renal tubules dilatation, hepatic blood sinusoid dilatation, pulmonary edema and malignant pleural effusion. The pathological sections analysis showed that the kidney and liver were significantly damaged, but the heart, spleen and stomach had no observed changes. Additionally, the hemanalysis showed an increase of white blood cells (WBC), middle cells (Mid), alanine aminotransferase (ALT), blood urine nitrogen (BUN) and uric acid (UA) in the blood. Moreover, the mice also displayed convulsions, mouth bleeding, piloerection, dyspnea and death after the injection of the venom. In conclusion, this venom has a strong toxicity to the kidney of the mice and the acute renal failure might be one of the most important factors for the death after a severe sting. Hopefully, the present study will provide a significant reference for the treatment of stings by the jellyfish S. meleagris in the future. PMID:25305553

Li, Rongfeng; Yu, Huahua; Yue, Yang; Liu, Song; Xing, Ronge; Chen, Xiaolin; Wang, Xueqin; Li, Pengcheng

2014-12-15

70

Ecosystem relevance of variable jellyfish biomass in the Irish Sea between years, regions and water types  

NASA Astrophysics Data System (ADS)

Monitoring the abundance and distribution of taxa is essential to assess their contribution to ecosystem processes. For marine taxa that are difficult to study or have long been perceived of little ecological importance, quantitative information is often lacking. This is the case for jellyfish (medusae and other gelatinous plankton). In the present work, 4 years of scyphomedusae by-catch data from the 2007-2010 Irish Sea juvenile gadoid fish survey were analysed with three main objectives: (1) to provide quantitative and spatially-explicit species-specific biomass data, for a region known to have an increasing trend in jellyfish abundance; (2) to investigate whether year-to-year changes in catch-biomass are due to changes in the numbers or in the size of medusa (assessed as the mean mass per individual), and (3) to determine whether inter-annual variation patterns are consistent between species and water masses. Scyphomedusae were present in 97% of samples (N = 306). Their overall annual median catch-biomass ranged from 0.19 to 0.92 g m-3 (or 8.6 to 42.4 g m-2). Aurelia aurita and Cyanea spp. (Cyanea lamarckii and Cyanea capillata) made up 77.7% and 21.5% of the total catch-biomass respectively, but species contributions varied greatly between sub-regions and years. No consistent pattern was detected between the distribution and inter-annual variations of the two genera, and contrasting inter-annual patterns emerged when considering abundance either as biomass or as density. Significantly, A. aurita medusae were heavier in stratified than in mixed waters, which we hypothesize may be linked to differences in timing and yield of primary and secondary productions between water masses. These results show the vulnerability of time-series from bycatch datasets to phenological changes and highlight the importance of taking species- and population-specific distribution patterns into account when integrating jellyfish into ecosystem models.

Bastian, Thomas; Lilley, Martin K. S.; Beggs, Steven E.; Hays, Graeme C.; Doyle, Thomas K.

2014-08-01

71

The Mode of Feeding of the Jelly-fish, Aurelia aurita, on the Smaller Organisms in the Plankton  

Microsoft Academic Search

WHILE engaged in investigations (carried out with the aid of a Government grant) on the oyster beds in the River Blackwater, a jelly-fish (about 8 cms. in diameter) kept as a pet was given large numbers of oyster larvæ to see what it would do with them. From the fate of the oyster larvæ it was at once seen that

J. H. Orton

1922-01-01

72

DalTREC 2006 QA System Jellyfish: Regular Expressions Mark-and-Match Approach to Question Answering  

Microsoft Academic Search

We present a question-answering system Jellyfish. Our approach is based on marking and matching steps that are implemented using the methodology of cascaded regular-expression rewriting. We present the system architecture and evaluate the system using the TREC 2004, 2005, and 2006 datasets. TREC 2004 was used as a training dataset, while TREC 2005 and TREC 2006 were used as testing

Vlado Keselj; Tony Abou-assaleh; Nick Cercone

2006-01-01

73

Presence of trans -6-Hexadecenoic acid in the White Jellyfish Aurelia aurita Lamarck and in a Caribbean gorgonian  

Microsoft Academic Search

An unusual fatty acid,trans-6-hexadecenoic, previously found in the lipids of marine turtles, the ocean sunfish and a sea anemone, is also present in\\u000a the lipids of the white jellyfish and in a common Caribbean sublittoral gorgonian.

S. N. Hooper; R. G. Ackman

1972-01-01

74

Characterisation of acid-soluble and pepsin-solubilised collagen from jellyfish (Cyanea nozakii Kishinouye).  

PubMed

Annual outbreaks of the Jellyfish (Cyanea nozakii Kishinouye) in the waters of the Yellow Sea and the East China Sea are regarded as a nuisance. Thus, utilizing this jellyfish species is of great significance to reduce harm to fisheries and marine environments. The yield of the acid-soluble collagens (ASCs) from the C. nozakii umbrella was 13.0% (dry weight) and that of the pepsin-solubilised collagens (PSCs) was 5.5% (dry weight). The SDS-PAGE patterns of the ASCs and PSCs differed from that of type I collagen, which indicate the presence of (?1)3. The denaturation temperature (Td) of the collagens was approximately 23.8°C. Fourier transform infrared spectroscopy proved that the ASCs and PSCs retained their helical structures and the As, Pb, and Hg content of the collagens, detected by ICP-MS, were considerably lower than the national standards. The results suggest that collagens isolated from C. nozakii can potentially be used as an alternative source of collagen for use in various applications. PMID:24360414

Zhang, Junjie; Duan, Rui; Huang, Lei; Song, Yujie; Regenstein, Joe M

2014-05-01

75

An Experimental Investigation of the Feeding Currents Generated by Upside-Down Jellyfish  

NASA Astrophysics Data System (ADS)

The flow characteristics of oblate medusan swimmers such as the moon jellyfish (Aurelia) have been examined to understand the bio-fluid mechanics of feeding via unsteady propulsion (see Dabiri et al., J. Exp. Biol., 2005). The upside-down jellyfish (Cassiopea) differs from the commonly observed swimming forms of scyphomedusae in that it is naturally found adhered to the muddy bottoms of shallow ocean waters. While they swim when disturbed, these organisms prefer to otherwise attach their bell surface to the floor and direct their oral arms upwards. Prey capture is accomplished by pulsatile contractions of the bell. The flow generated by the unsteady pulsations is examined using a combination of DPIV and morphological measurements. The phase-averaged flow field closely resembles a blowing jet centered about the body, with fluid entrainment occurring near the bell surface. Reversed flow regions are identified during both the contraction and relaxation phases. The effect of changing bell diameter on the jet as well as the production of flow structures is investigated. A qualitative comparison of the flow field between these organisms and swimming medusae will be presented.

Santhanakrishnan, Arvind; Miller, Laura

2009-11-01

76

A jellyfish-inspired jet propulsion robot actuated by an iris mechanism  

NASA Astrophysics Data System (ADS)

A jellyfish-inspired jet propulsion robot (JetPRo) is designed, fabricated, and characterized with the objective of creating a fast-swimming uncrewed undersea vehicle. JetPRo measures 7.9 cm in height, 5.7 cm in diameter and is designed to mimic the proficient jetting propulsion mechanism used by the hydromedusa Sarsia tubulosa, which measures approximately 1 cm in diameter. In order to achieve the uniform-bell contraction used by S. tubulosa, we develop a novel circumferential actuation technique based on a mechanical iris diaphragm. When triggered, this mechanism induces a volumetric change of a deformable silicone cavity to expel a jet of fluid and produces positive thrust. A theoretical jetting model is used to optimize JetPRo’s gait for maximum steady-state swimming velocity, a result achieved by minimizing the timing between the contraction and relaxation phases. We validate this finding empirically and quantify the swimming performance of the robot using video tracking and time resolved digital particle image velocimetry. JetPRo was able to produce discrete vortex rings shed before pinch off and swim upwards with a maximum steady-state velocity of 11.6 cm s-1, outperforming current state-of-the-art robotic jellyfish in velocity as well as diameter-normalized velocity.

Marut, Kenneth; Stewart, Colin; Michael, Tyler; Villanueva, Alex; Priya, Shashank

2013-09-01

77

The marine biologist--Bob Endean.  

PubMed

Bob Endean was a dedicated marine biologist with an extensive knowledge of coral reef communities in the Great Barrier Reef and fauna in subtropical Queensland waters. He commenced a study of venomous and poisonous marine animals dangerous to man at a time when the field was new, employing a variety of techniques to investigate the venom apparatus, mode of delivery of venom or toxin, mode of toxic action on excitable tissues, and biochemistry of venom or toxin. Determination of the pharmacological properties of crude venom from Conus marine snails advanced characterization of conotoxins by later workers. A study of four types of nematocysts from the box-jellyfish Chironex fleckeri provided information as to their structure, function, and mechanism of discharge; myotoxins T1 and T2 were isolated from microbasic mastigophores. Endean studied poisonous stonefish (Synanceia trachynis) and, with Ann Cameron, scorpionfish (Notesthes robusta); investigations of ciguatera and of paralytic shellfish poisoning were initiated. He organized the collection of Australian frogs which led to the isolation of caerulein by Erspamer in Italy. Endean highlighted the ecological danger of the population explosion of the crown-of-thorns starfish (Acanthaster planci) and provided the impetus for the creation of the Great Barrier Reef Marine Park. PMID:16952385

Hawgood, Barbara J

2006-12-01

78

Long-Term Fluctuations in Circalunar Beach Aggregations of the Box Jellyfish Alatina moseri in Hawaii, with Links to Environmental Variability  

PubMed Central

The box jellyfish Alatina moseri forms monthly aggregations at Waikiki Beach 8–12 days after each full moon, posing a recurrent hazard to swimmers due to painful stings. We present an analysis of long-term (14 years: Jan 1998– Dec 2011) changes in box jellyfish abundance at Waikiki Beach. We tested the relationship of beach counts to climate and biogeochemical variables over time in the North Pacific Sub-tropical Gyre (NPSG). Generalized Additive Models (GAM), Change-Point Analysis (CPA), and General Regression Models (GRM) were used to characterize patterns in box jellyfish arrival at Waikiki Beach 8–12 days following 173 consecutive full moons. Variation in box jellyfish abundance lacked seasonality, but exhibited dramatic differences among months and among years, and followed an oscillating pattern with significant periods of increase (1998–2001; 2006–2011) and decrease (2001–2006). Of three climatic and 12 biogeochemical variables examined, box jellyfish showed a strong, positive relationship with primary production, >2 mm zooplankton biomass, and the North Pacific Gyre Oscillation (NPGO) index. It is clear that that the moon cycle plays a key role in synchronizing timing of the arrival of Alatina moseri medusae to shore. We propose that bottom-up processes, likely initiated by inter-annual regional climatic fluctuations influence primary production, secondary production, and ultimately regulate food availability, and are therefore important in controlling the inter-annual changes in box jellyfish abundance observed at Waikiki Beach. PMID:24194856

Chiaverano, Luciano M.; Holland, Brenden S.; Crow, Gerald L.; Blair, Landy; Yanagihara, Angel A.

2013-01-01

79

Exploring vortex enhancement and manipulation mechanisms in jellyfish that contributes to energetically efficient propulsion  

PubMed Central

The ability of animals to propel themselves efficiently through a fluid medium is ecologically advantageous. Flexible components that influence vortex interactions are widespread among animal propulsors. However the mechanisms by which vortices are enhanced and appropriately positioned for thrust generation are still poorly understood. Here, we describe how kinematic propulsor movements of a jellyfish can enhance and reposition a vortex ring that allows the recapture of wake energy for secondary thrust generation and efficient locomotion. We use high-speed video and digital particle image velocimetry (DPIV) to resolve kinematics simultaneously with fluid structures. These results provide new insight into how animals can manipulate fluid structures to reduce metabolic energy demands of swimming muscles and may have implications in bio-inspired design.

Gemmell, Brad J; Costello, John H; Colin, Sean P

2014-01-01

80

Evidence-based treatment of jellyfish stings in North America and Hawaii.  

PubMed

We performed a systematic review of the evidence supporting various treatments for envenomation by jellyfish (cnidarian) and related organisms in North America and Hawaii. Our review produced 19 pertinent primary articles. Current research demonstrates variable response to treatment, often with conflicting results according to species studied, which contributes to considerable confusion about what treatment is warranted and efficacious. Our review suggests that vinegar causes pain exacerbation or nematocyst discharge in the majority of species. Hot water and topical lidocaine appear more widely beneficial in improving pain symptoms and are preferentially recommended. Unfortunately, they may be difficult to obtain at the site of envenomation, such as the beach or diving sites. In these instances, removing the nematocysts and washing the area with saltwater may be considered. If the envenomation is thought to be due to the bluebottle (Physalia), vinegar may be beneficial. PMID:22677532

Ward, Nicholas T; Darracq, Michael A; Tomaszewski, Christian; Clark, Richard F

2012-10-01

81

A Case of Delayed Flare-up Allergic Dermatitis Caused by Jellyfish Sting.  

PubMed

A 7-year-old boy, taking lessons at a yacht school at Enoshima in Kanagawa prefecture in Japan, recognized a linear eruption on his left lower leg during practice in August 2012. As it gradually enlarged, he visited a local medical clinic. The eruption initially improved with topical treatment but exacerbated in October of the same year. Although topical treatment was started again, there was minimal improvement, so the patient visited our hospital in December. At his first visit, he had a hard linear nodule on his left lower leg, and papules with excoriation were scattered over the lower limbs. Considering eczema, topical steroid treatment and occlusive dressing technique were started but the nodule remained. Based on the clinical course, clinical features, and laboratory findings, the lesion was considered to be delayed flare-up allergic dermatitis caused by a jellyfish sting [1]. PMID:25248421

Manabe, Yasuaki; Mabuchi, Tomotaka; Kawai, Mayu; Ota, Tami; Ikoma, Norihiro; Ozawa, Akira; Horita, Takushi

2014-01-01

82

The Occurrence of Type S1A Serine Proteases in Sponge and Jellyfish  

NASA Technical Reports Server (NTRS)

Although serine proteases are found in all kinds of cellular organisms and many viruses, the classic "chymotrypsin family" (Group S1A by th e 1998 Barrett nomenclature) has an unusual phylogenetic distribution , being especially common in animals, entirely absent from plants and protists, and rare among fungi. The distribution in Bacteria is larg ely restricted to the genus Streptomyces, although a few isolated occ urrences in other bacteria have been reported. The family may be enti rely absent from Archaea. Although more than a thousand sequences have been reported for enzymes of this type from animals, none of them ha ve been from early diverging phyla like Porifera or Cnidaria, We now report the existence of Group SlA serine proteases in a sponge (phylu m Porifera) and a jellyfish (phylum Cnidaria), making it safe to conc lude that all animal groups possess these enzymes.

Rojas, Ana; Doolittle, Russell F.

2003-01-01

83

Identification of the functional expression of adenosine A 3 receptor in pancreas using transgenic mice expressing jellyfish apoaequorin  

Microsoft Academic Search

To investigate the functional expression of adenosine A3 receptor (A3AR) in mammalian living tissues, we generated an apoaequorin-transgenic mouse that expresses jellyfish apoaequorin\\u000a throughout its body. The expression of apoaequorin under the control of a strong CAG promoter was detected in various tissues,\\u000a including the abdominal skin, adipose, ear, brain, esophagus, heart, inferior vena cava vessel, kidney, lens, liver, lung,

Kazuya Yamano; Katsuhiro Mori; Ryosuke Nakano; Machi Kusunoki; Miho Inoue; Mitsuo Satoh

2007-01-01

84

Stable isotope and biochemical fractionation in the marine pelagic food chain: the jellyfish Pelagia noctiluca and net zooplankton  

Microsoft Academic Search

In our field study we analyzed the C and H isotopic and biochemical (C, N, P, protein, lipid, carbohydrate) composition of the jellyfish Pelagia noctiluca (collected from the Gulf of Trieste in 1985 to 1986) and its presumed diet-net zooplankton. The mean d 13C (-18.8‰) and d D (-58.4‰) ratios of P. noctiluca showed enrichment in heavy isotopes relative to

A. Malej; J. Faganeli; J. Pezdi?

1993-01-01

85

First Complete Mitochondrial Genome Sequence from a Box Jellyfish Reveals a Highly Fragmented Linear Architecture and Insights into Telomere Evolution  

PubMed Central

Animal mitochondrial DNAs (mtDNAs) are typically single circular chromosomes, with the exception of those from medusozoan cnidarians (jellyfish and hydroids), which are linear and sometimes fragmented. Most medusozoans have linear monomeric or linear bipartite mitochondrial genomes, but preliminary data have suggested that box jellyfish (cubozoans) have mtDNAs that consist of many linear chromosomes. Here, we present the complete mtDNA sequence from the winged box jellyfish Alatina moseri (the first from a cubozoan). This genome contains unprecedented levels of fragmentation: 18 unique genes distributed over eight 2.9- to 4.6-kb linear chromosomes. The telomeres are identical within and between chromosomes, and recombination between subtelomeric sequences has led to many genes initiating or terminating with sequences from other genes (the most extreme case being 150 nt of a ribosomal RNA containing the 5? end of nad2), providing evidence for a gene conversion–based model of telomere evolution. The silent-site nucleotide variation within the A. moseri mtDNA is among the highest observed from a eukaryotic genome and may be associated with elevated rates of recombination. PMID:22117085

Smith, David Roy; Kayal, Ehsan; Yanagihara, Angel A.; Collins, Allen G.; Pirro, Stacy; Keeling, Patrick J.

2012-01-01

86

Diversity, Phylogeny and Expression Patterns of Pou and Six Homeodomain Transcription Factors in Hydrozoan Jellyfish Craspedacusta sowerbyi  

PubMed Central

Formation of all metazoan bodies is controlled by a group of selector genes including homeobox genes, highly conserved across the entire animal kingdom. The homeobox genes from Pou and Six classes are key members of the regulation cascades determining development of sensory organs, nervous system, gonads and muscles. Besides using common bilaterian models, more attention has recently been targeted at the identification and characterization of these genes within the basal metazoan phyla. Cnidaria as a diploblastic sister group to bilateria with simple and yet specialized organs are suitable models for studies on the sensory organ origin and the associated role of homeobox genes. In this work, Pou and Six homeobox genes, together with a broad range of other sensory-specific transcription factors, were identified in the transcriptome of hydrozoan jellyfish Craspedacusta sowerbyi. Phylogenetic analyses of Pou and Six proteins revealed cnidarian-specific sequence motifs and contributed to the classification of individual factors. The majority of the Craspedacusta sowerbyi Pou and Six homeobox genes are predominantly expressed in statocysts, manubrium and nerve ring, the tissues with sensory and nervous activities. The described diversity and expression patterns of Pou and Six factors in hydrozoan jellyfish highlight their evolutionarily conserved functions. This study extends the knowledge of the cnidarian genome complexity and shows that the transcriptome of hydrozoan jellyfish is generally rich in homeodomain transcription factors employed in the regulation of sensory and nervous functions. PMID:22558464

Hroudova, Miluse; Vojta, Petr; Strnad, Hynek; Krejcik, Zdenek; Ridl, Jakub; Paces, Jan; Vlcek, Cestmir; Paces, Vaclav

2012-01-01

87

Diversity, phylogeny and expression patterns of Pou and Six homeodomain transcription factors in hydrozoan jellyfish Craspedacusta sowerbyi.  

PubMed

Formation of all metazoan bodies is controlled by a group of selector genes including homeobox genes, highly conserved across the entire animal kingdom. The homeobox genes from Pou and Six classes are key members of the regulation cascades determining development of sensory organs, nervous system, gonads and muscles. Besides using common bilaterian models, more attention has recently been targeted at the identification and characterization of these genes within the basal metazoan phyla. Cnidaria as a diploblastic sister group to bilateria with simple and yet specialized organs are suitable models for studies on the sensory organ origin and the associated role of homeobox genes. In this work, Pou and Six homeobox genes, together with a broad range of other sensory-specific transcription factors, were identified in the transcriptome of hydrozoan jellyfish Craspedacusta sowerbyi. Phylogenetic analyses of Pou and Six proteins revealed cnidarian-specific sequence motifs and contributed to the classification of individual factors. The majority of the Craspedacusta sowerbyi Pou and Six homeobox genes are predominantly expressed in statocysts, manubrium and nerve ring, the tissues with sensory and nervous activities. The described diversity and expression patterns of Pou and Six factors in hydrozoan jellyfish highlight their evolutionarily conserved functions. This study extends the knowledge of the cnidarian genome complexity and shows that the transcriptome of hydrozoan jellyfish is generally rich in homeodomain transcription factors employed in the regulation of sensory and nervous functions. PMID:22558464

Hroudova, Miluse; Vojta, Petr; Strnad, Hynek; Krejcik, Zdenek; Ridl, Jakub; Paces, Jan; Vlcek, Cestmir; Paces, Vaclav

2012-01-01

88

Plastic Jellyfish.  

ERIC Educational Resources Information Center

Presents an environmental science activity designed to enhance students' awareness of the hazards of plastic waste for wildlife in aquatic environments. Discusses how students can take steps to reduce the effects of plastic waste. (WRM)

Moseley, Christine

2000-01-01

89

Jellyfish skin polysaccharides: extraction and inhibitory activity on macrophage-derived foam cell formation.  

PubMed

In this work, response surface methodology was used to determine optimum conditions for extraction of polysaccharides from jellyfish skin (JSP). The optimum parameters were found to be raw material to water ratio 1:7.5 (w/v), extraction temperature 100°C and extraction time 4h. Under these conditions, the JSP yield reached 1.007 mg/g. Papain (15 U/mL) in combination with Sevag reagent was beneficial in removing proteins from JSP. After precipitation with ethanol at final concentration of 40%, 60% and 80% in turn, three polysaccharide fractions of JSP1, JSP2 and JSP3 were obtained from JSP, respectively. The three fractions exhibited different physicochemical properties with respect to molecular weight distribution, monosaccharide composition, infrared absorption spectra, and glycosyl bond composition. In addition, JSP3 showed strong inhibitory effects on oxidized low-density lipoprotein (oxLDL) induced conversion of macrophages into foam cells, which possibly attributed to the down-regulation of some atherogenesis-related gene expressions. PMID:24721094

Zhang, Hai-Lin; Cui, Shao-Hua; Zha, Xue-Qiang; Bansal, Vibha; Xue, Lei; Li, Xiao-Long; Hao, Ran; Pan, Li-Hua; Luo, Jian-Ping

2014-06-15

90

Jellyfish: Special Tools for Biological Research on Earth and in Space  

NASA Technical Reports Server (NTRS)

The most intriguing nature of the jellyfish polyps is their ability to metamorphose, giving rise to tiny immature medusae called ephyrae which have a different form or shape from the polyps. The Aurelia Metamorphosis Test System was used to determine the subtle effects of hydrocarbons found in oil spills and the effects of X-irradiation on developing ephyrae. Currently, this test system is used to determine the effects of the gravity-less environment of outer space on the development and behavior of ephyrae. For this purpose, the effects of clinostat rotation on development of the ephyrae and their gravity receptor are being studied. The behavior of the ephyrae during 0 gravity achieved for short intervals of 30 seconds in parabolic flight is examined. The developing ephyrae and the mature ephyrae are exposed to gravity-less environment of outer space via a six or seven day shuttle experiment. If gravity receptors do form in outer space, they will be studied in detail using various types of microscopes, including the electron microscope, to determin whether they developed normally in space as compared with control on Earth.

Spangenberg, Dorothy B.

1991-01-01

91

Analgesic and antibutyrylcholinestrasic activities of the venom prepared from the Mediterranean jellyfish Pelagia noctiluca (Forsskal, 1775)  

PubMed Central

Background Toxins derived from jellyfishes have been exploited as a model for the development of new drug promising applications to treat neurodegenerative diseases. The present work is aimed to evaluate the acute toxicity of crude venom of Pelagia noctiluca and then to screen the analgesic and antibutyrylcholinestrasic (anti-BuChE) activities of the crude venom and its fractions. Methods Sephadex G75 gel was used to separate crude venom of Pelagia noctiluca, which led to some fractions. In addition, in vivo analgesic and in vitro plasma antibutyrylcholinestrasic activities were carried out with Pelagia crude venom and its fractions respectively. Results The crude venom and its fractions displayed analgesic and anti-BuChE activities at different doses without inducing acute toxicity. Fraction 2 possesses the highest analgesic and antibutyrylcholinestrasic properties. The crude venom and fraction 1 had shown to possess less significant inhibitory activity against analgesic and antibutyrylcholinestrasic models. Conclusions Based on this study, the crude venom of Pelagia noctiluca is found to be a useful tool for probing pharmacological activity. The purification and the determination of chemical structures of compounds of active fractions of the venom are under investigation. PMID:22691546

2012-01-01

92

Construction of chitin/PVA composite hydrogels with jellyfish gel-like structure and their biocompatibility.  

PubMed

High strength chitin/poly(vinyl alcohol) (PVA) composite hydrogels (RCP) were constructed by adding PVA into chitin dissolved in a NaOH/urea aqueous solution, and then by cross-linking with epichlorohydrin (ECH) and freezing-thawing process. The RCP hydrogels were characterized by field emission scanning electron microscopy, FTIR, differential scanning calorimetry, solid-state (13)C NMR, wide-angle X-ray diffraction, and compressive test. The results revealed that the repeated freezing/thawing cycles induced the bicrosslinked networks consisted of chitin and PVA crystals in the composite gels. Interestingly, a jellyfish gel-like structure occurred in the RCP75 gel with 25 wt % PVA content in which the amorphous and crystalline PVA were immobilized tightly in the chitin matrix through hydrogen bonding interaction. The freezing/thawing cycles played an important role in the formation of the layered porous PVA networks and the tight combining of PVA with the pore wall of chitin. The mechanical properties of RCP75 were much higher than the other RCP gels, and the compressive strength was 20× higher than that of pure chitin gels, as a result of broadly dispersing stress caused by the orderly multilayered networks. Furthermore, the cell culture tests indicated that the chitin/PVA composite hydrogels exhibited excellent biocompatibility and safety, showing potential applications in the field of tissue engineering. PMID:25077674

He, Meng; Wang, Zhenggang; Cao, Yan; Zhao, Yanteng; Duan, Bo; Chen, Yun; Xu, Min; Zhang, Lina

2014-09-01

93

Synthesis and characterization of polypyrrole composite actuator for jellyfish unmanned undersea vehicle  

NASA Astrophysics Data System (ADS)

In this paper, we investigated two geometries of conductive polymer-metal composite actuators: stripe and axial. The stripe actuator design consisted of gold coated poly(vinylidene difluoride) (PVDF) membrane with polypyrrole film grown potentiodynamically on top and bottom in sandwich structure. For axial type actuator, a gold coated core substrate was used which can be easily dissolved after polymerization of pyrrole. Synthesis of all samples was conducted using cyclic voltammometry technique. Results indicate that axial type actuator consisting of 0.25 M Pyrrole, 0.10 M TBAP and 0.5 M KCl in aqueous solution exhibits strain up to 6% and 18 kPa blocking stress for applied potential of 6V DC after 80 sec stimulation time. The axial type of actuator also exhibits rotary motion under DC voltage in electrolytic media. Experimental data was used to establish stress-strain and energy density-time response relationships. The stripe actuator with dimensions of 20mm length, 5mm width and 63?m thickness exhibited 2.8 mm transversal deflection at 7V and 0.2 Hz. Potential applications of conducting polymer based actuators include biometric jellyfish and expressive robotic head.

Tadesse, Yonas; Brennan, Jaclyn; Smith, Colin; Long, Timothy E.; Priya, Shashank

2010-04-01

94

Phenotypic plasticity in juvenile jellyfish medusae facilitates effective animal-fluid interaction  

PubMed Central

Locomotion and feeding in marine animals are intimately linked to the flow dynamics created by specialized body parts. This interaction is of particular importance during ontogeny, when changes in behaviour and scale challenge the organism with shifts in fluid regimes and altered functionality. Previous studies have indicated that Scyphozoan jellyfish ontogeny accommodates the changes in fluid dynamics associated with increasing body dimensions and velocities during development. However, in addition to scale and behaviour that—to a certain degree—underlie the control of the animal, flow dynamics are also dependent on external factors such as temperature. Here, we show phenotypic plasticity in juvenile Aurelia aurita medusae, where morphogenesis is adapted to altered fluid regimes imposed by changes in ambient temperature. In particular, differential proportional growth was found to compensate for temperature-dependent changes in viscous effects, enabling the animal to use adhering water boundary layers as ‘paddles’—and thus economize tissue—at low temperatures, while switching to tissue-dominated propulsion at higher temperatures where the boundary layer thickness is insufficient to serve for paddling. This effect was predicted by a model of animal–fluid interaction and confirmed empirically by flow-field visualization and assays of propulsion efficiency. PMID:20335200

Nawroth, J. C.; Feitl, K. E.; Colin, S. P.; Costello, J. H.; Dabiri, J. O.

2010-01-01

95

Clearance rates of ephyrae and small medusae of the common jellyfish Aurelia aurita offered different types of prey  

NASA Astrophysics Data System (ADS)

Prey selection and knowledge of the amounts of water processed by the early stages of the common jellyfish Aurelia aurita may at certain times of the year be crucial for understanding the plankton dynamics in marine ecosystems with mass occurrences of this jellyfish. In the present study we used two different methods ("clearance method" and "ingestion-rate method") to estimate the amount of water cleared per unit of time of different types and sizes of prey organisms offered to A. aurita ephyrae and small medusae. The mean clearance rates of medusae, estimated with Artemia sp. nauplii as prey by both methods, agreed well, namely 3.8 ± 1.4 l h - 1 by the clearance method and 3.2 ± 1.1 l h - 1 by the ingestion-rate method. Both methods showed that copepods (nauplii and adults) and mussel veligers are captured with considerably lower efficiency, 22 to 37% and 14 to 30%, respectively, than Artemia salina nauplii. By contrast, the water processing rates of ephyrae measured by the clearance method with A. salina nauplii as prey were 3 to 5 times lower than those measured by the ingestion-rate method. This indicates that the prerequisite of full mixing for using the clearance method may not have been fulfilled in the ephyrae experiments. The study demonstrates that the predation impact of the young stages of A. aurita is strongly dependent on its developmental stage (ephyra versus medusa), and the types and sizes of prey organisms. The estimated prey-digestion time of 1.3 h in a steady-state feeding experiment with constant prey concentration supports the reliability of the ingestion-rate method, which eliminates the negative "container effects" of the clearance method, and it seems to be useful in future jellyfish studies, especially on small species/younger stages in which both type and number of prey can be easily and precisely assessed.

Riisgård, Hans Ulrik; Madsen, Caroline V.

2011-01-01

96

Jellyfish support high energy intake of leatherback sea turtles (Dermochelys coriacea): video evidence from animal-borne cameras.  

PubMed

The endangered leatherback turtle is a large, highly migratory marine predator that inexplicably relies upon a diet of low-energy gelatinous zooplankton. The location of these prey may be predictable at large oceanographic scales, given that leatherback turtles perform long distance migrations (1000s of km) from nesting beaches to high latitude foraging grounds. However, little is known about the profitability of this migration and foraging strategy. We used GPS location data and video from animal-borne cameras to examine how prey characteristics (i.e., prey size, prey type, prey encounter rate) correlate with the daytime foraging behavior of leatherbacks (n = 19) in shelf waters off Cape Breton Island, NS, Canada, during August and September. Video was recorded continuously, averaged 1:53 h per turtle (range 0:08-3:38 h), and documented a total of 601 prey captures. Lion's mane jellyfish (Cyanea capillata) was the dominant prey (83-100%), but moon jellyfish (Aurelia aurita) were also consumed. Turtles approached and attacked most jellyfish within the camera's field of view and appeared to consume prey completely. There was no significant relationship between encounter rate and dive duration (p = 0.74, linear mixed-effects models). Handling time increased with prey size regardless of prey species (p = 0.0001). Estimates of energy intake averaged 66,018 kJ • d(-1) but were as high as 167,797 kJ • d(-1) corresponding to turtles consuming an average of 330 kg wet mass • d(-1) (up to 840 kg • d(-1)) or approximately 261 (up to 664) jellyfish • d(-1). Assuming our turtles averaged 455 kg body mass, they consumed an average of 73% of their body mass • d(-1) equating to an average energy intake of 3-7 times their daily metabolic requirements, depending on estimates used. This study provides evidence that feeding tactics used by leatherbacks in Atlantic Canadian waters are highly profitable and our results are consistent with estimates of mass gain prior to southward migration. PMID:22438906

Heaslip, Susan G; Iverson, Sara J; Bowen, W Don; James, Michael C

2012-01-01

97

The effects of level of expression of a jellyfish Shaker potassium channel: a positive potassium feedback mechanism  

PubMed Central

When jellyfish Shaker potassium channels (jShak2) are heterologously expressed in Xenopus oocytes at different levels they demonstrate density-dependent changes in electrical and kinetic properties of macroscopic currents. The activation and inactivation properties of jShak2 channels depend on the extracellular potassium concentration. In this study we present experimental data which show that expression-dependent changes in kinetic and electrical properties of jShak2 macroscopic currents can be explained by the positive feedback effect of dynamic accumulation of K+ in the perimembranal space. PMID:10226146

Grigoriev, N G; Spafford, J D; Spencer, A N

1999-01-01

98

Jellyfish Support High Energy Intake of Leatherback Sea Turtles (Dermochelys coriacea): Video Evidence from Animal-Borne Cameras  

PubMed Central

The endangered leatherback turtle is a large, highly migratory marine predator that inexplicably relies upon a diet of low-energy gelatinous zooplankton. The location of these prey may be predictable at large oceanographic scales, given that leatherback turtles perform long distance migrations (1000s of km) from nesting beaches to high latitude foraging grounds. However, little is known about the profitability of this migration and foraging strategy. We used GPS location data and video from animal-borne cameras to examine how prey characteristics (i.e., prey size, prey type, prey encounter rate) correlate with the daytime foraging behavior of leatherbacks (n?=?19) in shelf waters off Cape Breton Island, NS, Canada, during August and September. Video was recorded continuously, averaged 1:53 h per turtle (range 0:08–3:38 h), and documented a total of 601 prey captures. Lion's mane jellyfish (Cyanea capillata) was the dominant prey (83–100%), but moon jellyfish (Aurelia aurita) were also consumed. Turtles approached and attacked most jellyfish within the camera's field of view and appeared to consume prey completely. There was no significant relationship between encounter rate and dive duration (p?=?0.74, linear mixed-effects models). Handling time increased with prey size regardless of prey species (p?=?0.0001). Estimates of energy intake averaged 66,018 kJ•d?1 but were as high as 167,797 kJ•d?1 corresponding to turtles consuming an average of 330 kg wet mass•d?1 (up to 840 kg•d?1) or approximately 261 (up to 664) jellyfish•d-1. Assuming our turtles averaged 455 kg body mass, they consumed an average of 73% of their body mass•d?1 equating to an average energy intake of 3–7 times their daily metabolic requirements, depending on estimates used. This study provides evidence that feeding tactics used by leatherbacks in Atlantic Canadian waters are highly profitable and our results are consistent with estimates of mass gain prior to southward migration. PMID:22438906

Heaslip, Susan G.; Iverson, Sara J.; Bowen, W. Don; James, Michael C.

2012-01-01

99

Mitochondrial Genome of the Freshwater Jellyfish Craspedacusta sowerbyi and Phylogenetics of Medusozoa  

PubMed Central

The 17,922 base pairs (bp) nucleotide sequence of the linear mitochondrial DNA (mtDNA) molecule of the freshwater jellyfish Craspedacusta sowerbyi (Hydrozoa,Trachylina, Limnomedusae) has been determined. This sequence exhibits surprisingly low A+T content (57.1%), containing genes for 13 energy pathway proteins, a small and a large subunit rRNAs, and methionine and tryptophan tRNAs. Mitochondrial ancestral medusozoan gene order (AMGO) was found in the C. sowerbyi, as those found in Cubaia aphrodite (Hydrozoa, Trachylina, Limnomedusae), discomedusan Scyphozoa and Staurozoa. The genes of C. sowerbyi mtDNA are arranged in two clusters with opposite transcriptional polarities, whereby transcription proceeds toward the ends of the DNA molecule. Identical inverted terminal repeats (ITRs) flank the ends of the mitochondrial DNA molecule, a characteristic typical of medusozoans. In addition, two open reading frames (ORFs) of 354 and 1611 bp in length were found downstream of the large subunit rRNA gene, similar to the two ORFs of ORF314 and polB discovered in the linear mtDNA of C. aphrodite, discomedusan Scyphozoa and Staurozoa. Phylogenetic analyses of C. sowerbyi and other cnidarians were carried out based on both nucleotide and inferred amino acid sequences of the 13 mitochondrial energy pathway genes. Our working hypothesis supports the monophyletic Medusozoa being a sister group to Octocorallia (Cnidaria, Anthozoa). Within Medusozoa, the phylogenetic analysis suggests that Staurozoa may be the earliest diverging class and the sister group of all other medusozoans. Cubozoa and coronate Scyphozoa form a clade that is the sister group of Hydrozoa plus discomedusan Scyphozoa. Hydrozoa is the sister group of discomedusan Scyphozoa. Semaeostomeae is a paraphyletic clade with Rhizostomeae, while Limnomedusae (Trachylina) is the sister group of hydroidolinans and may be the earliest diverging lineage among Hydrozoa. PMID:23240028

Zou, Hong; Zhang, Jin; Li, Wenxiang; Wu, Shangong; Wang, Guitang

2012-01-01

100

Recombinant expression and solution structure of antimicrobial peptide aurelin from jellyfish Aurelia aurita  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Aurelin was overexpressed in Escherichia coli, and its spatial structure was studied by NMR. Black-Right-Pointing-Pointer Aurelin compact structure encloses helical regions cross-linked by three disulfide bonds. Black-Right-Pointing-Pointer Aurelin shows structural homology to the BgK and ShK toxins of sea anemones. Black-Right-Pointing-Pointer Aurelin binds to the anionic lipid vesicles, but does not interact with zwitterionic ones. Black-Right-Pointing-Pointer Aurelin binds to DPC micelle surface with moderate affinity via two helical regions. -- Abstract: Aurelin is a 40-residue cationic antimicrobial peptide isolated from the mezoglea of a scyphoid jellyfish Aurelia aurita. Aurelin and its {sup 15}N-labeled analogue were overexpressed in Escherichia coli and purified. Antimicrobial activity of the recombinant peptide was examined, and its spatial structure was studied by NMR spectroscopy. Aurelin represents a compact globule, enclosing one 3{sub 10}-helix and two {alpha}-helical regions cross-linked by three disulfide bonds. The peptide binds to anionic lipid (POPC/DOPG, 3:1) vesicles even at physiological salt concentration, it does not interact with zwitterionic (POPC) vesicles and interacts with the DPC micelle surface with moderate affinity via two {alpha}-helical regions. Although aurelin shows structural homology to the BgK and ShK toxins of sea anemones, its surface does not possess the 'functional dyad' required for the high-affinity interaction with the K{sup +}-channels. The obtained data permit to correlate the modest antibacterial properties and membrane activity of aurelin.

Shenkarev, Zakhar O.; Panteleev, Pavel V.; Balandin, Sergey V. [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation)] [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation); Gizatullina, Albina K.; Altukhov, Dmitry A. [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation) [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation); Moscow Institute of Physics and Technology (State University), Department of Physicochemical Biology and Biotechnology, Institutskii per., 9, 141700 Dolgoprudny, Moscow Region (Russian Federation); Finkina, Ekaterina I. [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation)] [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation); Kokryakov, Vladimir N. [Institute of Experimental Medicine, Russian Academy of Medical Sciences, Academica Pavlova str., 12, 197376 Saint-Petersburg (Russian Federation)] [Institute of Experimental Medicine, Russian Academy of Medical Sciences, Academica Pavlova str., 12, 197376 Saint-Petersburg (Russian Federation); Arseniev, Alexander S. [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation) [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation); Moscow Institute of Physics and Technology (State University), Department of Physicochemical Biology and Biotechnology, Institutskii per., 9, 141700 Dolgoprudny, Moscow Region (Russian Federation); Ovchinnikova, Tatiana V., E-mail: ovch@ibch.ru [Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str., 16/10, 117997 Moscow (Russian Federation); Moscow Institute of Physics and Technology (State University), Department of Physicochemical Biology and Biotechnology, Institutskii per., 9, 141700 Dolgoprudny, Moscow Region (Russian Federation)

2012-12-07

101

Jellyfish Lake, Palau: Regeneration of C, N, Si, and P in anoxic marine lake sediments  

USGS Publications Warehouse

Sediment cores from Jellyfish Lake were processed under an inert atmosphere and the pore waters extracted and analyzed for the following parameters: pH, titration alkalinity (TA), Cl-, H4SiO4, PO43-, NH4+, Ca2-, Mg2+, SO42-, and H2S. Additionally, in one set of pore-water samples (core 10), the ??13C of the ??CO2 was also determined. The TA, H4SiO4, PO43-, NH4+, and H2S increased with depth in the pore waters above anoxic bottom-water values. H2S values increased to 3.8 ??M. In one case, both H4SiO4 and PO43- concentrations increased to a maximum value and then decreased with depth, suggesting removal into solid phases. The H4SiO4 concentrations are equal to or greater than pore-water values observed in sediments underlying upwelling areas. PO43- concentrations are, in general, lower than pore-water values from terrigenous nearshore areas but higher than nearshore carbonate pore-water values from Florida Bay or Bermuda. The Ca2+, Cl-, and Mg2+: Cl- ratios show slight decreases in the top 15-20 cm, suggesting that authigenic carbonate may be forming. This suggestion is supported by the fact that the pore waters are saturated with respect to CaCO3 due to the very high TAs. The ??13C measurements of the pore-water ??CO2 are from a shorter core. These measurements reach their most negative concentration at 72 cm and then become slightly heavier. This change is accompanied by a decrease in TA, suggesting the onset of methanogenesis at this location in this core.

Lyons, W.B.; Lent, R.M.; Burnett, W.C.; Chin, P.; Landing, W.M.; Orem, W.H.; McArthur, J.M.

1996-01-01

102

Developmental and evolutionary aspects of the basic helix–loop–helix transcription factors Atonal-like 1 and Achaete-scute homolog 2 in the jellyfish  

Microsoft Academic Search

The close functional link of nerve and muscle cells in neuromuscular units has led to the hypothesis of a common evolutionary origin of both cell types. Jellyfish are well suited to evaluate this theory since they represent the most basal extant organisms featuring both striated muscle and a nervous system. Here we describe the structure and expression of two novel

Katja Seipel; Nathalie Yanze; Volker Schmid

2004-01-01

103

Intracellular Ca(2+) overload induced by extracellular Ca(2+) entry plays an important role in acute heart dysfunction by tentacle extract from the jellyfish Cyanea capillata.  

PubMed

The exact mechanism of acute heart dysfunction caused by jellyfish venom remains unclear for the moment. In the present study, we examined the problem caused by the tentacle extract (TE) from the jellyfish Cyanea capillata at the levels of whole animal, isolated heart, primarily cultured cardiomyocytes, and intracellular Ca(2+). The heart indexes, including HR, APs, LVPs, and MMLs, were all decreased significantly by TE in both whole animal and Langendorff-perfused isolated heart model. Imbalance of cardiac oxygen supply and demand also took place. In both Ca(2+)-containing and Ca(2+)-free bathing solutions, TE could cause obvious cytoplasmic Ca(2+) overload in NRVMs, but the cytoplasmic Ca(2+) increased faster, Ca(2+) overload peaks arrived earlier, and the morphological changes were more severe under the extracellular Ca(2+)-containing condition. L-type Ca(2+) channel blockers, as well as the inhibitor of ryanodine receptor (ryanodine), could improve the viability of NRVMs. Moreover, diltiazem significantly inhibited the acute heart dysfunction caused by TE in both Langendorff isolated heart model and whole animal. These results suggested that intracellular Ca(2+) overload induced by extracellular Ca(2+) entry plays an important role in acute heart failure by TE from the jellyfish C. capillata. Inhibition of extracellular Ca(2+) influx is a promising antagonistic alternative for heart damage by jellyfish venom. PMID:24563080

Zhang, Lin; He, Qian; Wang, Qianqian; Zhang, Bo; Wang, Beilei; Xu, Feng; Wang, Tao; Xiao, Liang; Zhang, Liming

2014-09-01

104

Macrobenthic community structure and species composition in the Yellow Sea and East China Sea in jellyfish bloom  

NASA Astrophysics Data System (ADS)

To understand the characteristics of macrobenthic structures and the relationship between environment and benthic assemblages in jellyfish bloom, we studied the macrobenthos and related environmental factors in the coastal waters of the Yellow Sea and East China Sea. Data were collected during two seasonal cruises in April and August of 2011, and analyzed with multivariate statistical methods. Up to 306 macrobenthic species were registered from the research areas, including 115 species of Polychaeta, 78 of Crustacea, 61 of Mollusca, 30 of Echinodermata, and 22 of other groups. Nine polychaete species occurred at frequencies higher than 25% from the sampling stations: Lumbrineris longifolia, Notomastus latericeus, Ninöe palmata, Ophelina acuminata, Nephtys oligobranchia, Onuphis geophiliformis, Glycera chirori, Terebellides stroemii, and Aricidea fragilis. Both the average biomass and abundance of macrobenthos are higher in August (23.8 g/m2 and 237.7 ind./m2) than those in April (11.3 g/m2 and 128 ind./m2); the dissimilarity of macrobenthic structures among stations is as high as 70%. In terms of the dissimilarity values, we divided the stations into four clusters in spring and eight in summer. The ABC curve shows that the macrofauna communities in high jellyfish abundance were not changed. Canonical correspondence analysis showed that depth, temperature, median grain size, total organic carbon of sediment and total nitrogen in sediment were important factors affecting the macrozoobenthic community in the study area.

Peng, Songyao; Li, Xinzheng; Wang, Hongfa; Zhang, Baolin

2014-05-01

105

Central circuitry in the jellyfish Aglantha. II: The ring giant and carrier systems  

PubMed

1. The ring giant axon in the outer nerve ring of the jellyfish Aglantha digitale is a multinucleate syncytium 85 % of which is occupied by an electron-dense fluid-filled vacuole apparently in a Gibbs­Donnan equilibrium with the surrounding band of cytoplasmic cortex. Micropipette recordings show small (-15 to -25 mV) and large (-62 to -66 mV) resting potentials. Low values, obtained with a high proportion of the micropipette penetrations, are assumed to be from the central vacuole; high values from the cytoplasmic cortex. Background electrical activity includes rhythmic oscillations and synaptic potentials representing hair cell input caused by vibration. 2. After the ring giant axon has been cut, propagating action potentials evoked by stimulation are conducted past the cut and re-enter the axon on the far side. The system responsible (the carrier system) through-conducts at a velocity approximately 25 % of that of the ring giant axon and is probably composed of small neurones running in parallel with it. Numerous small neurones are seen by electron microscopy, some making one-way and some two-way synapses with the ring giant. 3. Despite their different conduction velocities, the two systems normally appear to fire in synchrony and at the velocity of the ring giant axon. We suggest that, once initiated, ring giant spikes propagate rapidly around the margin, firing the carrier neurones through serial synapses and giving them, in effect, the same high conduction velocity. Initiation of ring giant spikes can, however, require input from the carrier system. The spikes are frequently seen to be mounted on slow positive potentials representing summed carrier postsynaptic potentials. 4. The carrier system fires one-for-one with the giant axons of the tentacles and may mediate impulse traffic between the latter and the ring giant axon. We suggest that the carrier system may also provide the pathways from the ring giant to the motor giant axons used in escape swimming. 5. The findings show that the ring giant axon functions in close collaboration with the carrier system, increasing the latter's effective conduction velocity, and that interactions with other neuronal sub-systems are probably mediated exclusively by the carrier system. PMID:9320190

Mackie; Meech

1995-01-01

106

Effects of collagen and collagen hydrolysate from jellyfish (Rhopilema esculentum) on mice skin photoaging induced by UV irradiation.  

PubMed

Collagen (JC) was extracted from jellyfish (Rhopilema esculentum) and hydrolyzed to prepare collagen hydrolysate (JCH). The protective effects of JC and JCH against UV-induced damages to mice skin were evaluated and compared in this article. JC and JCH could alleviate the UV-induced abnormal changes of antioxidative indicators, including the superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities and the contents of glutathione (GSH) and malondiaidehyde (MDA). JC and JCH could protect skin lipid and collagen from the UV radiation damages. Furthermore, the changes of total ceramide and glycosaminoglycan in skin were recovered significantly by JC and JCH. The action mechanisms mainly involved the antioxidative properties and the repairing to endogenous collagen synthesis of JC and JCH in vivo. JCH with the lower molecular weight showed much higher effects than JC. The results indicated that JCH was a novel antiphotoaging agent from natural resources. PMID:19723203

Zhuang, Yongliang; Hou, Hu; Zhao, Xue; Zhang, Zhaohui; Li, Bafang

2009-08-01

107

Settlement of Planulae of the Moon Jellyfish Aurelia aurita onto Hydrophilic Polycarbonate Plates Modified by Atmospheric Plasma Treatment  

PubMed Central

It has been reported that planula larvae of some jellyfish prefer artificial substrates for settlement. This research focused on the relationship between the settlement of planulae and the wettability of artificial substrate surfaces. We used atmospheric plasmas to change the wettability of the surfaces of polycarbonate (PC) plates because plasma treatment has no chemical side effects. The treatment made the surfaces hydrophilic, as evidenced by the decrease of contact angle from 85° to 35°. X-ray photoelectron spectroscopy revealed that the change of wettability of the PC plates could be attributed to N2, which was probably ionized in the air above the plates. Scanning electron microscopy revealed no difference in the surface morphology of the plates before and after plasma treatment. Results of bioassays using treated PC plates showed that planulae tended to preferentially settle on hydrophobic surfaces. PMID:24465603

Tomaru, Akiko; Sasaki, Ryota; Miyahara, Hidekazu; Okino, Akitoshi; Ogawa, Nobuhiro; Hamasaki, Koji

2014-01-01

108

Effects of turbidity on survival of larval ayu and red sea bream exposed to predation by jack mackerel and moon jellyfish  

Microsoft Academic Search

We conducted laboratory experiments to examine the effects of turbidity on the survival of red sea bream Pagrus major and ayu Plecoglossus altivelis altivelis larvae when exposed to either visual (jack mackerel juveniles) or tactile (moon jellyfish) predators. The experiments were\\u000a conducted in 30-l tanks with three different levels of turbidity obtained by dissolving 0, 50, or 300 ppm kaolin. Predators

Ryosuke Ohata; Reiji Masuda; Masahiro Ueno; Yuichi Fukunishi; Yoh Yamashita

2011-01-01

109

Reproductive strategy of the jellyfish Aurelia aurita (Cnidaria Scyphomedusae) in the Suez Canal and its migration between the Red Sea and Mediterranean  

Microsoft Academic Search

The life history of the common jellyfish A. aurita (Linnaeus) in the Suez Canal was investigated by monthly sampling over a 28 month period from September 2006 to December 2008. Young medusae of 2–3 cm diameter appeared during February\\/March. Growth was rapid. Some specimens of this cohort reached 16 cm and spawned by March\\/May and then decreased in size or

Hamed A. El-Serehy; Khaled A. Al-Rasheid

2011-01-01

110

First Report of a Peroxiredoxin Homologue in Jellyfish: Molecular Cloning, Expression and Functional Characterization of CcPrx4 from Cyanea capillata  

PubMed Central

We first identified and characterized a novel peroxiredoxin (Prx), designated as CcPrx4, from the cDNA library of the tentacle of the jellyfish Cyanea capillata. The full-length cDNA sequence of CcPrx4 consisted of 884 nucleotides with an open reading frame encoding a mature protein of 247 amino acids. It showed a significant homology to peroxiredoxin 4 (Prx4) with the highly conserved F-motif (93FTFVCPTEI101), hydrophobic region (217VCPAGW222), 140GGLG143 and 239YF240, indicating that it should be a new member of the Prx4 family. The deduced CcPrx4 protein had a calculated molecular mass of 27.2 kDa and an estimated isoelectric point of 6.3. Quantitative real-time PCR analysis showed that CcPrx4 mRNA could be detected in all the jellyfish tissues analyzed. CcPrx4 protein was cloned into the expression vector, pET-24a, and expressed in Escherichia coli Rosetta (DE3) pLysS. Recombinant CcPrx4 protein was purified by HisTrap High Performance chelating column chromatography and analyzed for its biological function. The results showed that the purified recombinant CcPrx4 protein manifested the ability to reduce hydrogen peroxide and protect supercoiled DNA from oxidative damage, suggesting that CcPrx4 protein may play an important role in protecting jellyfish from oxidative damage. PMID:24413803

Ruan, Zengliang; Liu, Guoyan; Wang, Beilei; Zhou, Yonghong; Lu, Jia; Wang, Qianqian; Zhao, Jie; Zhang, Liming

2014-01-01

111

Preliminary Results of the in Vivo and in Vitro Characterization of a Tentacle Venom Fraction from the Jellyfish Aurelia aurita  

PubMed Central

The neurotoxic effects produced by a tentacle venom extract and a fraction were analyzed and correlated by in vivo and in vitro approaches. The tentacle venom extract exhibited a wide range of protein components (from 24 to >225 kDa) and produced tetanic reactions, flaccid paralysis, and death when injected into crabs. Two chromatography fractions also produced uncontrolled appendix movements and leg stretching. Further electrophysiological characterization demonstrated that one of these fractions potently inhibited ACh-elicited currents mediated by both vertebrate fetal and adult muscle nicotinic acetylcholine receptors (nAChR) subtypes. Receptor inhibition was concentration-dependent and completely reversible. The calculated IC50 values were 1.77 ?g/?L for fetal and 2.28 ?g/?L for adult muscle nAChRs. The bioactive fraction was composed of a major protein component at ~90 kDa and lacked phospholipase A activity. This work represents the first insight into the interaction of jellyfish venom components and muscle nicotinic receptors. PMID:24322597

Ponce, Dalia; Lopez-Vera, Estuardo; Aguilar, Manuel B.; Sanchez-Rodriguez, Judith

2013-01-01

112

Spatiotemporal characteristics and mechanisms of intracellular Ca(2+) increases at fertilization in eggs of jellyfish (Phylum Cnidaria, Class Hydrozoa).  

PubMed

We have clarified, for the first time, the spatiotemporal patterns of intracellular Ca(2+) increases at fertilization and the Ca(2+)-mobilizing mechanisms in eggs of hydrozoan jellyfish, which belong to the evolutionarily old diploblastic phylum, Cnidaria. An initial Ca(2+) increase just after fertilization took the form of a Ca(2+) wave starting from one cortical region of the egg and propagating to its antipode in all of four hydrozoan species tested: Cytaeis uchidae, Cladonema pacificum, Clytia sp., and Gonionema vertens. The initiation site of the Ca(2+) wave was restricted to the animal pole, which is known to be the only area of sperm-egg fusion in hydrozoan eggs, and the wave propagating velocity was estimated to be 4.2-5.9 mum/s. After a Ca(2+) peak had been attained by the initial Ca(2+) wave, the elevated Ca(2+) gradually declined and returned nearly to the resting value at 7-10 min following fertilization. Injection of inositol 1,4,5-trisphosphate (IP(3)), an agonist of IP(3) receptors (IP(3)R), was highly effective in inducing a Ca(2+) increase in unfertilized eggs; IP(3) at a final intracellular concentration of 12-60 nM produced a fully propagating Ca(2+) wave equivalent to that observed at fertilization. In contrast, a higher concentration of cyclic ADP-ribose (cADPR), an agonist of ryanodine receptors (RyR), only generated a localized Ca(2+) increase that did not propagate in the egg. In addition, caffeine, another stimulator of RyR, was completely without effect. Sperm-induced Ca(2+) increases in Gonionema eggs were severely affected by preinjection of heparin, an inhibitor of Ca(2+) release from IP(3)R. These results strongly suggest that there is a well-developed IP(3)R-, but not RyR-mediated Ca(2+) release mechanism in hydrozoan eggs and that the former system primarily functions at fertilization. Our present data also demonstrate that the spatial characteristics and mechanisms of Ca(2+) increases at fertilization in hydrozoan eggs resemble those reported in higher triploblastic animals. PMID:15733659

Deguchi, Ryusaku; Kondoh, Eri; Itoh, Junko

2005-03-15

113

Effect of low dissolved oxygen concentrations on behavior and predation rates on red sea bream Pagrus major larvae by the jellyfish Aurelia aurita and by juvenile Spanish mackerel Scomberomorus niphonius  

Microsoft Academic Search

A shift in outcomes of predator-prey interactions in plankton community may occur at sublethal dissolved oxygen concentrations that commonly occur in coastal waters. Laboratory experiments were conducted to investigate how a decline in dissolved oxygen concentration alters the predation rate on fish larvae by two estuarine predators. Behavior and consumption of larval fish by moon jellyfish Aurelia aurita (103.1±12.4 mm in

J. Shoji; R. Masuda; Y. Yamashita; M. Tanaka

2005-01-01

114

For the Classroom: "Plastic" Jellyfish.  

ERIC Educational Resources Information Center

Describes an activity in which students monitor the plastic waste production in their households, research its effects on freshwater and marine life, and propose ways to lessen the problem. Provides objectives, background information, materials, procedures, extension activities, and an evaluation for students. (Author/RT)

Current: The Journal of Marine Education, 1989

1989-01-01

115

COLUMBIA SCIENCE REVIEW Jellyfish Takeover  

E-print Network

of Caffeine Coffee on the Brain Graphene A Scientific Magic Trick Vol. 7, Issue 2: Spring 2011 #12;2 Columbia;3Spring 2011 Cocktail Science Privacy in the Digital Age The New Era of Bubbles The Science of Caffeine recently dis- covered a way to use naturally oc- curring crystals to make 3D objects appear to disappear

Qian, Ning

116

Biological Invasions by Marine Jellyfish  

Microsoft Academic Search

Comparatively little research has been conducted on the ecology of invasive organisms in marine ecosystems when balanced against\\u000a their terrestrial counterparts (Carlton and Geller 1993). Perhaps rates of invasions in marine systems are simply lower than\\u000a in other systems, but more likely lack of scrutiny, difficulty with taxonomic resolution, and unusual life-history characters\\u000a of marine organisms cause the vast majority

William M. Graham; Keith M. Bayha

117

Central Neural Circuitry in the Jellyfish Aglantha  

Microsoft Academic Search

Like other hydrozoan medusae, Aglantha lacks a brain, but the two marginal nerve rings function together as a central nervous system. Twelve neuronal and two excitable epithelial conduction systems are described and their interactions summarized. Aglantha differs from most medusae in having giant axons. It can swim and contract its tentacles in two distinct ways (escape and slow). Escape responses

George O. Mackie

2004-01-01

118

Propulsion in Cubomedusae: Mechanisms and Utility  

PubMed Central

Evolutionary constraints which limit the forces produced during bell contractions of medusae affect the overall medusan morphospace such that jet propulsion is limited to only small medusae. Cubomedusae, which often possess large prolate bells and are thought to swim via jet propulsion, appear to violate the theoretical constraints which determine the medusan morphospace. To examine propulsion by cubomedusae, we quantified size related changes in wake dynamics, bell shape, swimming and turning kinematics of two species of cubomedusae, Chironex fleckeri and Chiropsella bronzie. During growth, these cubomedusae transitioned from using jet propulsion at smaller sizes to a rowing-jetting hybrid mode of propulsion at larger sizes. Simple modifications in the flexibility and kinematics of their velarium appeared to be sufficient to alter their propulsive mode. Turning occurs during both bell contraction and expansion and is achieved by generating asymmetric vortex structures during both stages of the swimming cycle. Swimming characteristics were considered in conjunction with the unique foraging strategy used by cubomedusae. PMID:23437122

Colin, Sean P.; Costello, John H.; Katija, Kakani; Seymour, Jamie; Kiefer, Kristen

2013-01-01

119

A shift to parasitism in the jellyfish symbiont Symbiodinium microadriaticum  

E-print Network

. For symbionts that exchange costly benefits with hosts, we must explain what prevents them from parasitizing (Trench 1993), mammalian gut-symbionts (Savage 1977), nitrogen-fixing bacteria in plant roots (Sprent et al. 1987) and bioluminescent bacteria in fish and squids (Ruby 1996). Detailed research studying

Sachs, Joel

120

Field experiments in the control of a Jellyfish tracking ROV  

Microsoft Academic Search

Continuing ocean experiments demonstrate specific applications in which a jelly-tracking ROV pilot assist enhances collection of scientific data. Recent results have repeatedly demonstrated the tracker's ability to follow a jelly target for extended periods, as long as 34 minutes. Thus far, experimental demonstrations of the jelly tracker have incorporated a linear control law. This paper presents extensions to the control

Jason Rife; Stephen M. Rock

2002-01-01

121

The conserved mitochondrial gene distribution in relatives of Turritopsis nutricula, an immortal jellyfish  

PubMed Central

Turritopsis nutricula (T. nutricula) is the one of the known reported organisms that can revert its life cycle to the polyp stage even after becoming sexually mature, defining itself as the only immortal organism in the animal kingdom. Therefore, the animal is having prime importance in basic biological, aging, and biomedical researches. However, till date, the genome of this organism has not been sequenced and even there is no molecular phylogenetic study to reveal its close relatives. Here, using phylogenetic analysis based on available 16s rRNA gene and protein sequences of Cytochrome oxidase subunit-I (COI or COX1) of T. nutricula, we have predicted the closest relatives of the organism. While we found Nemopsis bachei could be closest organism based on COX1 gene sequence; T. dohrnii may be designated as the closest taxon to T. nutricula based on rRNA. Moreover, we have figured out four species that showed similar root distance based on COX1 protein sequence. PMID:25352727

Devarapalli, Pratap; Kumavath, Ranjith N; Barh, Debmalya; Azevedo, Vasco

2014-01-01

122

Ecosystem Engineers in the Pelagic Realm: Alteration of Habitat by Species Ranging from Microbes to Jellyfish  

E-print Network

within the water column and on the benthos. By causing hypoxia, changing light regimes, and influencing micro-algae to forest trees, and the con- cept has been applied to a wide range of spatial and temporal

Dabiri, John O.

123

Pattern- and contrast-dependent visual response in the box jellyfish Tripedalia cystophora.  

PubMed

Cubomedusae possess a total of 24 eyes, some of which are structurally similar to vertebrate eyes. Accordingly, the medusae also display a range of light-guided behaviours including obstacle avoidance, diurnal activity patterns and navigation. Navigation is supported by spatial resolution and image formation in the so-called upper lens eye. Further, there are indications that obstacle avoidance requires image information from the lower lens eye. Here we use a behavioural assay to examine the obstacle avoidance behaviour of the Caribbean cubomedusa Tripedalia cystophora and test whether it requires spatial resolution. The possible influence of the contrast and orientation of the obstacles is also examined. We show that the medusae can only perform the behaviour when spatial information is present, and fail to avoid a uniformly dark wall, directly proving the use of spatial vision. We also show that the medusae respond stronger to high contrast lines than to low contrast lines in a graded fashion, and propose that the medusae use contrast as a semi-reliable measure of distance to the obstacle. PMID:24031055

Garm, Anders; Hedal, Ida; Islin, Majken; Gurska, Daniela

2013-12-15

124

Proteomic characterisation of toxins isolated from nematocysts of the South Atlantic jellyfish Olindias  

E-print Network

proteins from diverse animal phyla, including cone- snails, snakes, spiders, scorpions, wasp, bee, such as sphingo- myelin phosphodiesterase B (SMase B) that has only been described in certain spider venoms properties that might generate new leads in the discovery of novel pharmacologically active drugs. Crown

Morandini, Andre C.

125

Evolution of box jellyfish (Cnidaria: Cubozoa), a group of highly toxic invertebrates  

PubMed Central

Cubozoa (Cnidaria: Medusozoa) represents a small clade of approximately 50 described species, some of which cause serious human envenomations. Our understanding of the evolutionary history of Cubozoa has been limited by the lack of a sound phylogenetic hypothesis for the group. Here, we present a comprehensive cubozoan phylogeny based on ribosomal genes coding for near-complete nuclear 18S (small subunit) and 28S (large subunit) and partial mitochondrial 16S. We discuss the implications of this phylogeny for our understanding of cubozoan venom evolution, biogeography and life-history evolution. Our phylogenetic hypothesis suggests that: (i) the last common ancestor of Carybdeida probably possessed the mechanism(s) underlying Irukandji syndrome, (ii) deep divergences between Atlantic and Indo-Pacific clades may be explained by ancient vicariant events, and (iii) sexual dimorphism evolved a single time in concert with complex sexual behaviour. Furthermore, several cubozoan taxa are either para- or polyphyletic, and we address some of these taxonomic issues by designating a new family, Carukiidae, a new genus, Copula, and by redefining the families Tamoyidae and Tripedaliidae. Lastly, cubozoan species identities have long been misunderstood and the data presented here support many of the recent scientific descriptions of cubozoan species. However, the results of a phylogeographic analysis of Alatina moseri from Hawai'i and Alatina mordens from Australia indicate that these two nominal species represent a single species that has maintained metapopulation cohesion by natural or anthropogenic dispersal. PMID:19923131

Bentlage, Bastian; Cartwright, Paulyn; Yanagihara, Angel A.; Lewis, Cheryl; Richards, Gemma S.; Collins, Allen G.

2010-01-01

126

The conserved mitochondrial gene distribution in relatives of Turritopsis nutricula, an immortal jellyfish.  

PubMed

Turritopsis nutricula (T. nutricula) is the one of the known reported organisms that can revert its life cycle to the polyp stage even after becoming sexually mature, defining itself as the only immortal organism in the animal kingdom. Therefore, the animal is having prime importance in basic biological, aging, and biomedical researches. However, till date, the genome of this organism has not been sequenced and even there is no molecular phylogenetic study to reveal its close relatives. Here, using phylogenetic analysis based on available 16s rRNA gene and protein sequences of Cytochrome oxidase subunit-I (COI or COX1) of T. nutricula, we have predicted the closest relatives of the organism. While we found Nemopsis bachei could be closest organism based on COX1 gene sequence; T. dohrnii may be designated as the closest taxon to T. nutricula based on rRNA. Moreover, we have figured out four species that showed similar root distance based on COX1 protein sequence. PMID:25352727

Devarapalli, Pratap; Kumavath, Ranjith N; Barh, Debmalya; Azevedo, Vasco

2014-01-01

127

Passive energy recapture in jellyfish contributes to propulsive advantage over other metazoans  

E-print Network

, Danesh Taftid , and Shashank Priyad a Whitman Center, Marine Biological Laboratory, Woods Hole, MA 02543; b Biology Department, Providence College, Providence, RI 02908; c Marine Biology/ Environmental number (Ef) (5­7), a metric originally designed to quantify the propulsive performance of ships. The Ef

Dabiri, John O.

128

DalTREC 2005 QA System Jellyfish: Mark-and-Match Approach to Question Answering  

Microsoft Academic Search

This is the second year that Dalhousie University actively participated in TREC. Three runs were submitted for the Question Answering track. Our results are below the median; however, they're signifantly larger than minimal, the lesson learnt will guide our future development of the system. Our approach was based on a mark-and-match methodology with regular expression rewriting.

Tony Abou-assaleh; Nick Cercone; Jon Doyle; Vlado Keselj; Chris Whidden

2005-01-01

129

Rock preference of planulae of jellyfish Aurelia aurita (Linnaeus 1758) for settlement in the laboratory  

NASA Astrophysics Data System (ADS)

Planulae of Aurelia aurita were exposed to 11 types of rocks (basalt, gabbro, granite, rhyolite, sandstone, limestone, conglomerate, gneiss, quartzite, marble and schist) to examine their attachment preference among rock material and position. Numbers of attached polyps was the highest on marble and the least on limestone. Their preference with regard to settling position was the same among the rocks, showing the highest density of polyps on the underside (88.5%) compared to upper (23.6%) and perpendicular sides (10.3%) of rock. The results showed that while position preference is more important than rock property, higher numbers of polyps were observed in rocks with a medium surface hardness.

Yoon, Won Duk; Choi, Sung-Hwan; Han, Changhoon; Park, Won Gyu

2014-06-01

130

Vortex motion in the ocean: In situ visualization of jellyfish swimming and feeding flows  

E-print Network

. Dabiri and Morteza Gharib California Institute of Technology, Pasadena, California 91125 Sean P. Colin.H.C. and No. CTS-0309671 to M.G. and Aurelia medusae provided by the Cabrillo Marine Aquarium. 1 J. O. Dabiri

Dabiri, John O.

131

Jellyfish Lake, Palau: early diagenesis of organic matter in sediments of an anoxic marine lake  

USGS Publications Warehouse

The major postdepositional change in the sedimentary organic matter is carbohydrate biodegradation. Lignin and aliphatic substances are preserved in the sediments. Dissolved organic matter in pore waters is primarily composed of carbohydrates, reflecting the degradation of sedimentary carbohydrates. Rate constants for organic carbon degradation and sulfate reduction in sediments of the lake are about 10?? lower than in other anoxic sediments. This may reflect the vascular plant source and partly degraded nature of the organic matter reaching the sediments of the lake. -from Authors

Orem, W.H.; Burnett, W.C.; Landing, W.M.; Lyons, W.B.; Showers, W.

1991-01-01

132

Jellyfish and Ctenophore Blooms Coincide with Human Proliferations and Environmental Perturbations  

NASA Astrophysics Data System (ADS)

Human populations have been concentrated along and exploiting the coastal zones for millennia. Of regions with the highest human impacts on the oceans ( Halpern et al. 2008 ), 6 of the top 10 have recently experienced blooms or problems with jellies. I review the time lines of human population growth and their effects on the coastal environment. I explore evidence suggesting that human activities - specifically, seafood harvest, eutrophication, hard substrate additions, transport of nonindigenous species, aquaculture, and climate change - may benefit jelly populations. Direct evidence is lacking for most of these factors; however, numerous correlations show abundant jellies in areas with warm temperatures and low forage fish populations. Jelly populations fluctuate in ˜10- and ˜20-year cycles in concert with solar and climate cycles. Global warming will provide a rising baseline against which climate cycles will cause fluctuations in jelly populations. The probable acceleration of anthropogenic effects may lead to further problems with jellies.

Purcell, Jennifer E.

2012-01-01

133

Reproduction of the giant jellyfish, Nemopilema nomurai (Scyphozoa: Rhizostomeae), in 2006-2008 as peripherally-transported populations  

NASA Astrophysics Data System (ADS)

This study investigated the sexual maturation process, release of spermatozoa or eggs and oocyte diameter of the rhizostomid medusae Nemopilema nomurai using samples collected from August 2006 to June 2008 from the waters around Korea and Japan, including peripheral areas outside the species’ usual habitat. Immature medusae were observed from June to October only in the western sector of the study area. The onset of spermatozoa and egg release occurred in September and October, respectively, and peaked in December and January. Medusae migrated eastward from source areas with the Tsushima Warm Current, where they formed gametes and spawned. Peak position and maximum oocyte diameter increased as the gonads developed according to the size-frequency distribution of oocytes. No fertilized eggs or embryos were found in the gonads. The correlation was analyzed with bell diameter, maximum oocyte diameter, sampling date, surface water temperature and gonad color to estimate which environmental factors and maturation indices were related to the maturation stage of females. Maturation stage correlated well with maximum oocyte diameter, which correlated negatively with surface water temperature. There was no significant correlation between bell diameter and maturation stage. Therefore, bell diameter was inappropriate for determining maturation index. Sex could not be distinguished clearly by gonad color. However, light pink gonads were more prevalent in males and various deep colors such as orange and brown were more frequent in female medusae.

Iguchi, Naoki; Lee, Hye Eun; Yoon, Won Duk; Kim, Suam

2010-06-01

134

Gene duplication and recruitment of a specific tropomyosin into striated muscle cells in the jellyfish Podocoryne carnea.  

PubMed

Cnidaria are the most basal animal phylum in which smooth and striated muscle cells have evolved. Since the ultrastructure of the mononucleated striated muscle is similar to that of higher animals, it is of interest to compare the striated muscle of Cnidaria at the molecular level to that of triploblastic phyla. We have used tropomyosins, a family of actin binding proteins to address this question. Throughout the animal kingdom, a great diversity of tropomyosin isoforms is found in non-muscle cells but only a few conserved tropomyosins are expressed in muscle cells. Muscle tropomyosins are all similar in length and share conserved termini. Two cnidarian tropomyosins have been described previously but neither of them is expressed in striated muscle cells. Here, we have characterized a new tropomyosin gene Tpm2 from the hydrozoan Podocoryne carnea. Expression analysis by RT-PCR and by whole mount in situ hybridization demonstrate that Tpm2 is exclusively expressed in striated muscle cells of the medusa. The Tpm2 protein is shorter in length than its counterparts from higher animals and differs at both amino and carboxy termini from striated muscle isoforms of higher animals. Interestingly, Tpm2 differs considerably from Tpm1 (only 19% identity) which was described previously in Podocoryne carnea. This divergence indicates a functional separation of cytoskeletal and striated muscle tropomyosins in cnidarians. These data contribute to our understanding of the evolution of the tropomyosin gene family and demonstrate the recruitment of tropomyosin into hydrozoan striated muscles during metazoan evolution. J. Exp. Zool. (Mol. Dev. Evol.) 285:378-386, 1999. PMID:10578111

Gröger, H; Callaerts, P; Gehring, W J; Schmid, V

1999-12-15

135

Oceana Magazine Summer 2012: Ask Dr. Pauly: Are the Oceans Jellifying?  

E-print Network

in the commercial caught species, and they often threw away the jellyfish that they had collected without recording television and newspaper reports have been filled with stories about jellyfish outbreaks in recent years

Pauly, Daniel

136

50 CFR 217.84 - Mitigation.  

Code of Federal Regulations, 2013 CFR

...of fish, jellyfish, and/or large Sargassum rafts are observed within the mitigation-monitoring...until the fish, jellyfish, and/or Sargassum rafts that cause the postponement...concentrations of fish or jellyfish, and large Sargassum mats. The presence of diving...

2013-10-01

137

50 CFR 217.84 - Mitigation.  

Code of Federal Regulations, 2012 CFR

...of fish, jellyfish, and/or large Sargassum rafts are observed within the mitigation-monitoring...until the fish, jellyfish, and/or Sargassum rafts that cause the postponement...concentrations of fish or jellyfish, and large Sargassum mats. The presence of diving...

2012-10-01

138

Is sleep's 'supreme mystery' unraveling? An evolutionary analysis of sleep encounters no mystery; nor does life's earliest sleep, recently discovered in jellyfish.  

E-print Network

advancing his theory of natural selection Darwin [1] sought2,3]. Darwin’s choice of the eye to buttress his theorytheory would absolutely break down’’. The vertebrate eye was the obvious potential counterexample, and Darwin

Kavanau, Julian L.

2006-01-01

139

UNITED STATES DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration  

E-print Network

(Dosidicus gigas). 6. Examine feeding habits and distributions of jellyfish. 7. Collect adult Pacific (Euphausiacea). 4. Observe seabird and marine mammal distribution and abundance. 5. Collect Humboldt squid

140

Tropical Marine Biology Baja California Sur  

E-print Network

; subtidal habitat) -Does Safe Sea's sunblock with jellyfish sting protective lotion make nematocysts stings hurt less than regular sunblock? (field sample collection, lab experiments; subtidal habitat) Summer

Acevedo, Alejandro

141

Engineering novel fluorescent proteins.  

E-print Network

??Fluorescent proteins are intrinsically fluorescent, genetically encodable tags that can be expressed in many heterologous organisms. Originally cloned from jellyfish and corals, these proteins and… (more)

Shaner, Nathan Christopher

2006-01-01

142

Identify key design elements of desired function  

E-print Network

) Relative signal amplitude m Dichroic mirror Emission filter Excitation filter Light source Imaging diode Medusoid muscle 1mm 1mm Supplementary Fig. 2 Jellyfish-inspired Medusoid muscle and body design. a, Muscle architecture in juvenile jellyfish showing radial and circular fiber orientations. Note: Composite image

Dabiri, John O.

143

The First Mutant of the Aequorea Victoria Green Fluorescent Protein That Forms a Red Chromophore  

E-print Network

of the jellyfish A. Victoria where GFP played a role of secondary emitter transforming blue light from ReceiVed February 27, 2008 ABSTRACT: Green fluorescent protein (GFP) from a jellyfish, Aequorea Victoria efforts of academia and industry toward generating its red fluorescent mutants, no GFP variants

Verkhusha, Vladislav V.

144

21 CFR 123.3 - Definitions.  

Code of Federal Regulations, 2012 CFR

...means fresh or saltwater finfish, crustaceans, other forms of aquatic animal life (including, but not limited to, alligator, frog, aquatic turtle, jellyfish, sea cucumber, and sea urchin and the roe of such animals) other than birds or mammals,...

2012-04-01

145

21 CFR 123.3 - Definitions.  

Code of Federal Regulations, 2013 CFR

...means fresh or saltwater finfish, crustaceans, other forms of aquatic animal life (including, but not limited to, alligator, frog, aquatic turtle, jellyfish, sea cucumber, and sea urchin and the roe of such animals) other than birds or mammals,...

2013-04-01

146

21 CFR 123.3 - Definitions.  

Code of Federal Regulations, 2011 CFR

...means fresh or saltwater finfish, crustaceans, other forms of aquatic animal life (including, but not limited to, alligator, frog, aquatic turtle, jellyfish, sea cucumber, and sea urchin and the roe of such animals) other than birds or mammals,...

2011-04-01

147

Ecology, 87(8), 2006, pp. 19671972 2006 by the the Ecological Society of America  

E-print Network

AGGREGATIONS AND LEATHERBACK TURTLE FORAGING PATTERNS IN A TEMPERATE COASTAL ENVIRONMENT JONATHAN D. R Cork, Lee Maltings, Prospect Row, Cork, Ireland Abstract. Leatherback turtles (Dermochelys coriacea; foraging ecology; gelatinous zooplankton; jellyfish; leatherback turtles; planktivore; predator

Hays, Graeme

148

pSAT vectors: a modular series of plasmids for autofluorescent protein tagging and expression of multiple genes in plants  

E-print Network

transformation. Introduction Since the discovery of the jellyfish green autofluorescent protein (GFP) (Chalfie et- vanced by development of multicolor spectral variants of GFP, such as yellow (YFP), cyan (CFP) and blue

Citovsky, Vitaly

149

Sea Anemone Genome Reveals Ancestral Eumetazoan Gene Repertoire and Genomic Organization  

Microsoft Academic Search

Sea anemones are seemingly primitive animals that, along with corals, jellyfish, and hydras, constitute the oldest eumetazoan phylum, the Cnidaria. Here, we report a comparative analysis of the draft genome of an emerging cnidarian model, the starlet sea anemone Nematostella vectensis. The sea anemone genome is complex, with a gene repertoire, exon-intron structure, and large-scale gene linkage more similar to

Nicholas H. Putnam; Mansi Srivastava; Uffe Hellsten; Bill Dirks; Jarrod Chapman; Asaf Salamov; Astrid Terry; Harris Shapiro; Erika Lindquist; Vladimir V. Kapitonov; Jerzy Jurka; Grigory Genikhovich; Igor V. Grigoriev; Susan M. Lucas; Robert E. Steele; John R. Finnerty; Ulrich Technau; Mark Q. Martindale; Daniel S. Rokhsar

2007-01-01

150

J. M. Wilson 4500 words Department of Mathematics  

E-print Network

the paleontologist found himself sitting next to his work table and search- ing for something to say. "Have you ever, you know what I mean. Just fifty miles from here, right outside Orlando." He dragged a squarish dark on a Portuguese man-of-war." "A what?" "It's a kind of jellyfish. Anyway, in a few days we'll start dissecting

Wilson, J. Michael

151

A Sea Creature Treasury. Project CAPE Teaching Module K-2b.  

ERIC Educational Resources Information Center

Fifteen interdisciplinary lessons on marine invertebrates (mollusks, echinoderms, and jellyfish) are provided in this unit designed for students in kindergarten and in grades 1 and 2. Each lesson includes lesson concept, competency goals, objectives, materials needed, background information, teacher preparation, and activities suitable for use in…

Gray, Carmen P.; Forrest, Diane W.

152

Learning about Marine Biology. Superific Science Book VI. A Good Apple Science Activity Book for Grades 5-8+.  

ERIC Educational Resources Information Center

Based on the assumption that most students have a natural curiosity about the plant and animal life residing in the oceans, this document provides students in grades five through eight with activities in marine biology. The book provides illustrated information and learning activities dealing with: (1) diatoms; (2) the life cycle of the jellyfish;…

Conway, Lorraine

153

Design analysis of self-organized and frameless swimming bio-robots with cardiomyocyte gel  

Microsoft Academic Search

This article describes the computer analysis and experimental result of building up jellyfish robot from cardiomyocytes gel consisting of rat cardiomyocytes and collagen gel. Previous studies show the cardiomyocyte gel has some unique abilities such as autonomous pulsation, shape-controllable by mold or driven by chemical energy. We thought that the pulsation of gels could be utilized as mobility function of

Ryuichi TAKEMURA; Takayuki HOSHINO; Yoshitake AKIYAMA; Keisuke MORISHIMA

2010-01-01

154

MARINE ECOLOGY PROGRESS SERIES Mar Ecol Prog Ser  

E-print Network

.int-res.com*Email: vvasas@yahoo.com FEATURE ARTICLE Eutrophication and overfishing in temperate nearshore pelagic food webs, in eutrophicated sys- tems; (2) the contribution of human influences on food webs, focusing on bottom-up (increased fish species. Jellyfish act as a buffer in eutrophicated and overfished systems, as they retain

Chittka, Lars

155

MARINE ECOLOGY PROGRESS SERIES Mar Ecol Prog Ser  

E-print Network

), eutrophication (Parsons & Lalli 2002, Purcell et al. 2007), hypoxia (Decker et al. 2004, Thuesen et al. 2005 and jellyfish as a function of eutrophication and water clarity Matilda Haraldsson1 , Kajsa Tönnesson1 , Peter succession on how mass of the system distributes when going from an oligotrophic to a eutrophic system

Aksnes, Dag L.

156

Disclaimer: The opinions expressed in this publication  

E-print Network

resulting in huge overpopulation of jellyfish; and the profound implications of a future world with no fish revealing the impact of overfishing on our oceans, had its world premiere at the Sundance Film Festival in the World Cinema Documentary Competition. Sundance took place in Park City, Utah, January 15-25, 2009

157

Lecture 23: History of Metazoan Life Early metazoan life  

E-print Network

Lecture 23: History of Metazoan Life · Early metazoan life ­ Fossils · Metazoan macroevolution ­ Endosymbiont hypothesis Multicellular life: origins · Metazoans · Earliest fossils: ­ Ediacaran: 565 mya ­ Sponges, jellyfish, comb jellies ­ Radial or no symmetry ­ Diploblasts: ecto- and endoderm Metazoan

158

Newsinperspective THESE aliens we'd rather not  

E-print Network

are accidental tourists ­ arriving either by ship or by escaping from aquaculture farms. "Every day, thousands habitat ­ more than half of its fish are aliens, as are the majority of animals and plants living by escaped farmed salmon and the notorious comb jellyfish, which all but wiped out native species

Tipple, Brett

159

EEssttiimmaattiinngg rraatteess aanndd ppaatttteerrnnss ooff mmoorrpphhoollooggiiccaall eevvoolluuttiioonn ffrroomm pphhyyllooggeenniieess  

E-print Network

in evolutionary biology is to explain the great phenotypic diversity of life. Why are there organisms that look as varied as octopi, redwoods, earthworms, seagulls, centipedes, jellyfish, and Scarlett Johansson. Skinner et al. [9], in a study published in BMC Evolutionary Biology, have now provided an extensive

Wiens, John J.

160

A fast, lock-free approach for efficient parallel counting of occurrences of k-mers  

PubMed Central

Motivation: Counting the number of occurrences of every k-mer (substring of length k) in a long string is a central subproblem in many applications, including genome assembly, error correction of sequencing reads, fast multiple sequence alignment and repeat detection. Recently, the deep sequence coverage generated by next-generation sequencing technologies has caused the amount of sequence to be processed during a genome project to grow rapidly, and has rendered current k-mer counting tools too slow and memory intensive. At the same time, large multicore computers have become commonplace in research facilities allowing for a new parallel computational paradigm. Results: We propose a new k-mer counting algorithm and associated implementation, called Jellyfish, which is fast and memory efficient. It is based on a multithreaded, lock-free hash table optimized for counting k-mers up to 31 bases in length. Due to their flexibility, suffix arrays have been the data structure of choice for solving many string problems. For the task of k-mer counting, important in many biological applications, Jellyfish offers a much faster and more memory-efficient solution. Availability: The Jellyfish software is written in C++ and is GPL licensed. It is available for download at http://www.cbcb.umd.edu/software/jellyfish. Contact: gmarcais@umd.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:21217122

Marçais, Guillaume; Kingsford, Carl

2011-01-01

161

Crossota millsae (Cnidaria: Trachymedusae: Rhopalonematidae), a new species of viviparous hydromedusa from the deep sea off California and Hawaii  

Microsoft Academic Search

A new species of deep-sea jellyfish, Crossota millsae (Cnidaria: Hydrozoa: Trachymedusae: Rho- palonematidae), is described from the North Pacific Ocean off California and Hawaii. Discrete depth sampling showed this species lives at depths below 1000 meters in both geographic locations. The species is more abundant off California than off Hawaii. The greatest population densities were found at ~2500 m off

ERIK V. THUESEN

162

Natural infections of aposymbiotic Cassiopea xamachana scyphistomae from environmental pools of Symbiodinium  

Microsoft Academic Search

The ability to acquire different types of the symbiotic dinoflagellate Symbiodinium (zooxanthellae) from the environment was investigated using aposymbiotic scyphistomae of the jellyfish Cassiopea xamachana. Non-symbiotic scyphistomae were placed on an offshore Florida patch reef and in Florida Bay during 3- and 5-day periods in March, and 5-day exposures in May, August and December of 2003. Scyphistomae were maintained in

Daniel J. Thornhill; Michael W. Daniel; Todd C. LaJeunesse; Gregory W. Schmidt; William K. Fitt

2006-01-01

163

Handle with Care! Mid-Atlantic Marine Animals That Demand Your Respect. Educational Series No. 26. Third Printing.  

ERIC Educational Resources Information Center

Generally speaking, marine organisms found along middle Atlantic shores are not considered threatening to people. However, some of these animals can cause problems, either upon simple contact with the skin, as in the case of some jellyfish, or through careless handling. In addition, larger inhabitants of coastal waters (such as sharks) must always…

Lucy, Jon

164

Marine & Other Invertebrates. Animal Life in Action[TM]. Schlessinger Science Library. [Videotape].  

ERIC Educational Resources Information Center

This 23-minute videotape for grades 5-8, presents the myriad of animal life that exists on the planet. Students can view and perform experiments and investigations that help explain animal traits and habits. Invertebrate animals include a vast array of spineless creatures. In this video, students discover marine lifeforms such as jellyfish,…

2000

165

Phylum Cnidaria Introduction  

E-print Network

with radially distributed sense organs Neurons serve sensory and motor systems. Epithelial layer of a cnidarian cnidaria (sea anemones and jellyfish) may have two nerve nets. Slow conducting network Fine fibers end cells beneath epithelium Bigger fibers, faster conduction of impulse Enables major responses

Cochran-Stafira, D. Liane

166

Breathtaking Discoveries: How Basic Research Led to Treatments for Asthma  

NSDL National Science Digital Library

FASEB Breakthroughs in Bioscience article. A number of animal models have played an invaluable part in key discoveries related to asthma. Experiments involving species as diverse as jellyfish, guinea pigs, and dogs have all shed light on the allergic response that is now known to play a role in asthma.

Margie Patlak (Federation of American Societies for Experimental Biology Office of Public Affairs)

2010-07-12

167

Glow Dog Glow  

E-print Network

Broadcast Transcript: South Korean researchers, ever striving to be top in science, have cloned a glow-in-the-dark dog. The little beagle was engineered by inserting genes from species--like jellyfish--that produce fluorescent proteins. The gene...

Hacker, Randi

2011-08-17

168

540 | VOL.10 NO.6 | JUNE2013 | natURE mEthOdS Improved tools for the Brainbow toolbox  

E-print Network

neurons with multiple distinct colors. this method has been adapted to non-neuronal cells in mice and to neurons in fish and flies, but its full potential has yet to be realized in the mouse brain. here we to image Brainbow-expressing tissue. The discovery that recombinant jellyfish GFP fluoresces when expressed

Cai, Long

169

Floating debris in the Ligurian Sea, north-western Mediterranean Stefano Aliani a,*, Annalisa Griffa a,b  

E-print Network

swimmers; marine animals can become caught in discarded fishing nets and lines, grocery bags, six) consume floating trash bags and balloons, likely mistaking them for jellyfish. Several seabird species floor by fishing trawls and submarine dives * Corresponding author. Tel.: +39-01-8797-8311; fax: +39

Griffa, Annalisa

170

Leatherback turtles: The menace of plastic  

Microsoft Academic Search

The leatherback, Dermochelyscoriacea, is a large sea turtle that feeds primarily on jellyfish. Floating plastic garbage could be mistaken for such prey. Autopsy records of 408 leatherback turtles, spanning 123 years (1885–2007), were studied for the presence or absence of plastic in the GI tract. Plastic was reported in 34% of these cases. If only cases from our first report

N. Mrosovsky; Geraldine D. Ryan; Michael C. James

2009-01-01

171

Chemical Nature of the Light Emitter of the Aequorea Green Fluorescent Protein  

Microsoft Academic Search

The jellyfish Aequorea victoria possesses in the margin of its umbrella a green fluorescent protein (GFP, 27 kDa) that serves as the ultimate light emitter in the bioluminescence reaction of the animal. The protein is made up of 238 amino acid residues in a single polypeptide chain and produces a greenish fluorescence (lambda max = 508 nm) when irradiated with

Haruki Niwa; Satoshi Inouye; Takashi Hirano; Tatsuki Matsuno; Satoshi Kojima; Masayuki Kubota; Mamoru Ohashi; Frederick I. Tsuji

1996-01-01

172

Generalization and Optimization of Biological and Biomimetic Ejection Mechanisms  

Microsoft Academic Search

Unsteady mechanisms for fluid ejection are found in biological systems from jellyfish to the human heart. An understanding of these mechanisms is needed to correct pathologies in natural systems and to design biomimetic systems. In particular, the formation process of the recurring vortex ring motif must be studied. It has been previously shown that ring formation is limited by the

John O. Dabiri; Michele Milano; Morteza Gharib

2003-01-01

173

Puncture mechanics of cnidarian cnidocysts: a natural actuator  

Microsoft Academic Search

BACKGROUND: Cnidocysts isolated from cnidarian organisms are attractive as a drug-delivery platform due to their fast, efficient delivery of toxins. The cnidocyst could be utilized as the means to deliver therapeutics in a wearable drug-delivery patch. Cnidocysts have been previously shown to discharge upon stimulation via electrical, mechanical, and chemical pathways. Cnidocysts isolated from the Portuguese Man O' War jellyfish

Shawn C Oppegard; Peter A Anderson; David T Eddington

2009-01-01

174

Hands-on Science. How Do Sea Critters Make Their Moves?  

ERIC Educational Resources Information Center

Three science experiments teach elementary school students about marine-life locomotion. One teaches primary students how octopi and jellyfish move, using balloons and umbrellas. Another teaches K-6 students the up and down movement of fish in water, using condiment packets. A third teaches 4-6 students about the effect of fish swim bladders,…

VanCleave, Janice

1998-01-01

175

Seascapes: Glimpses of Our Water World.  

ERIC Educational Resources Information Center

Presented is a collection of newspaper articles prepared by the Delaware Sea Grant Marine Advisory Service during the summer of 1978. Subjects addressed are bioluminescence, beachcomber finds, gulls, beach erosion, marine research activities, barnacles, sand, seaweed, jellyfish, shore restaurants, diving mammals, and tides. (Author/BW)

Hardin, Jan

176

THE MORPHOLOGY OF STINGING CELLS IN THE MARINE INVERTEBRATE NUDIBRANCH, CRATENA PILATA  

EPA Science Inventory

The association between the marine invertebrate nudibranch, Cratena pilata, and its food source has intrigued researchers for many years. These nudibranchs, or shell-less snails, obtain stinging cells by feeding on the jellyfish-like coelenterate, Tubularia sp. It is believed tha...

177

A study of the possibility of sprites in the atmospheres of other planets  

Microsoft Academic Search

Sprites are a spectacular type of transient luminous events which occur above thunderstorms immediately after lightning. They have shapes of giant jellyfish, carrots, or columns and last tens of milliseconds. In Earth's atmosphere, sprites mostly emit in red and blue wavelengths from excited N2 and N2+ and span a vertical range between 50 and 90 km above the surface. The

Yoav Yair; Yukihiro Takahashi; Roy Yaniv; Ute Ebert; Yukihiro Goto

2009-01-01

178

Effects of environment on source water for desalination plants on the eastern coast of Saudi Arabia  

Microsoft Academic Search

A study was carried out in the sea adjacent to a major MSF plant where a new 24MGD SWRO plant is being commissioned. Data were collected on the topographical feature of the marine basin, water quality and plankton of the intake zone. The incidents of planktonic bloom, influx of invasive organisms like jellyfish and macrofouling organisms and ingress of marine

P. K. Abdul Azis; Ibrahim Al-Tisan; Mohammad Al-Daili; Troy N. Green; Abdul Ghani I. Dalvi; M. A. Javeed

2000-01-01

179

Green Fluorescent Protein as a Novel Indicator of Antimicrobial Susceptibility in Aureobasidium pullulans  

Microsoft Academic Search

Presently there is no method available that allows noninvasive and real-time monitoring of fungal suscep- tibility to antimicrobial compounds. The green fluorescent protein (GFP) of the jellyfish Aequoria victoria was tested as a potential reporter molecule for this purpose. Aureobasidium pullulans was transformed to express cytosolic GFP using the vector pTEFEGFP (A. J. Vanden Wymelenberg, D. Cullen, R. N. Spear,

JEREMY S. WEBB; SARAH R. BARRATT; HRISTO SABEV; MARIANNE NIXON; IAN M. EASTWOOD; MALCOLM GREENHALGH; PAULINE S. HANDLEY; GEOFFREY D. ROBSON

2001-01-01

180

Illuminating plant biology: using fluorescent proteins for  

E-print Network

fixation treatments [4]. GFP has been successfully expressed in almost every transformable organism being. The molecular cloning of green fluorescent protein (GFP) was one of the most important break- throughs the Pacific Ocean jellyfish Aequorea victoria [2], the use of GFP and its subsequent fluo- rescent derivatives

Jackson, David

181

The utility of green fluorescent protein in transgenic plants  

Microsoft Academic Search

The green fluorescent protein (GFP) from the jellyfish Aequorea victoria has proven to be a powerful tool in plant genetic transformation studies. This paper reviews the history and the progression of the expression of GFP variants in transgenic plants. The distinguishing features of the most useful GFPs, such as those including the S65T chromophore mutation and those with dual excitation

C. N. Stewart Jr

2001-01-01

182

Transactions of the ASAE Vol. 48(2): 841-847 E 2005 American Society of Agricultural Engineers ISSN 0001-2351 841  

E-print Network

-263-3887; e-mail: finer.1@osu.edu. GFP expression to follow the transformation process in different apple in many different areas of biology is the green fluorescent protein (GFP) gene from jellyfish a computer-controlled automated system to monitor GFP gene expression over time. The automated system

Finer, John J.

183

Fluid Mechanics 25 March 2009  

E-print Network

: application to predator­prey interaction in jellyfish feeding J. PENG1 AND J. O. DABIRI1,2 1 Bioengineering@caltech.edu #12;76 J. Peng and J. O. Dabiri with R = 2f f + 2p , A = R St , St = 2 9 a L 2 Re. (1.2) Equation (1

Dabiri, John O.

184

Introduction The ability to directly measure physical interactions between  

E-print Network

techniques include dye visualizations (e.g., Didden 1979; Dabiri et al. 2005) and digital particle image velocime- try, or DPIV (e.g., Adrian 1991; Willert and Gharib 1991; Drucker and Lauder 1999; Dabiri of ciliated larvae (Emlet 1990) and affects the structure of LCS in the wake of a jellyfish (Katija and Dabiri

Dabiri, John O.

185

INTRODUCTION As a swimming or flying animal moves through its environment,  

E-print Network

) and many other modes of locomotion (Nauwelaerts et al., 2005; Dabiri et al., 2006) have used this wake jellyfish (Shadden et al., 2006; Peng and Dabiri, 2007). The identification of upstream coherent structures Jifeng Peng1, * and John O. Dabiri1,2 1 Bioenginee

Dabiri, John O.

186

Sensitivity analysis of kinematic approximations in dynamic medusan swimming models  

Microsoft Academic Search

Models of medusan swimming typically rely on kinematic approximations to observed animal morphology to make such investigations tractable. The effect of these simplifications on the accuracy of predicted dynamics has not been examined in detail. We conduct a case study of the scyphozoan jellyfish Chrysaora fuscescens to isolate and quantify the sensitivity of dynamic models to common kinematic approximations. It

John O. Dabiri; Morteza Gharib

2003-01-01

187

Green fluorescent protein as a vital marker for non-destructive detection of transformation events in transgenic plants  

Microsoft Academic Search

Transformation of plants is a popular tool for modifying various desirable traits. Marker genes, like those encoding for bacterial ?-glucuronidase (GUS), firefly luciferase (LUC) or jellyfish green fluorescent protein (GFP) have been shown to be very useful for establishing of efficient transformation protocols. Due to favourable properties such as no need of exogenous substrates and easy visualization, GFP has been

Marek Hraška; Slavomír Rakouský; Vladislav ?urn

2006-01-01

188

Effects of a flexible margin on Robojelly vortex structures  

NASA Astrophysics Data System (ADS)

An Unmanned Underwater Vehicle (UUV) inspired by jellyfish morphology and propulsion mechanism, termed ``Robojelly,'' was used to analyze the effects of the flexible margin on jellyfish propulsion. The natural animal has a bell section which deforms at a different phase then the rest of the bell. This lagging section, referred to as flexible margin or flap, is delimited by the bell margin and an inflexion point. The flap was replicated on the robotic vehicle by a flexible passive material to conduct a systematic parametric study. In a preliminary experiment, Robojelly was tested without a flap and with a flap. This revealed a thrust increase over an order of magnitude. We hypothesize that the length of this passive flap affects the vortex ring circulation strength of the jellyfish which can lead to higher efficiency and thrust. Velocity field measurements were performed using planar Time Resolved Digital Particle Image Velocimetry (TRDPIV) to analyze the change in vortex structures as a function of flap length. The robot input parameters stayed constant over the different configurations tested thus maintaining a near constant power consumption. Results clearly demonstrate that the flap plays an important role in the propulsion mechanism of Robojelly and provides an anatomical understanding of natural jellyfish.

Villanueva, Alex; Stewart, Kelley; Vlachos, Pavlos; Priya, Shashank

2011-11-01

189

A variant of yellow fluorescent protein with fast and efficient maturation for cell-biological applications  

Microsoft Academic Search

The green fluorescent protein (GFP) from the jellyfish Aequorea victoria has provided a myriad of applications for biological systems. Over the last several years, mutagenesis studies have improved folding properties of GFP (refs 1,2). However, slow maturation is still a big obstacle to the use of GFP variants for visualization. These problems are exacerbated when GFP variants are expressed at

Takeharu Nagai; Keiji Ibata; Eun Sun Park; Mie Kubota; Katsuhiko Mikoshiba; Atsushi Miyawaki

2002-01-01

190

ften in genetics research, explo-ration of an exceedingly rare con-  

E-print Network

that maybe the worm could be a way to study this," he recalled. He also knew that the implications could, the brain le- sions associated with Parkinson's disease. Ozelius and colleagues found torsinA bind- ing lab before pursuing a jellyfish/worm route to

Caldwell, Guy

191

Reconstructing Source-Sink Dynamics in a Population with a Pelagic Dispersal Phase  

PubMed Central

For many organisms, the reconstruction of source-sink dynamics is hampered by limited knowledge of the spatial assemblage of either the source or sink components or lack of information on the strength of the linkage for any source-sink pair. In the case of marine species with a pelagic dispersal phase, these problems may be mitigated through the use of particle drift simulations based on an ocean circulation model. However, when simulated particle trajectories do not intersect sampling sites, the corroboration of model drift simulations with field data is hampered. Here, we apply a new statistical approach for reconstructing source-sink dynamics that overcomes the aforementioned problems. Our research is motivated by the need for understanding observed changes in jellyfish distributions in the eastern Bering Sea since 1990. By contrasting the source-sink dynamics reconstructed with data from the pre-1990 period with that from the post-1990 period, it appears that changes in jellyfish distribution resulted from the combined effects of higher jellyfish productivity and longer dispersal of jellyfish resulting from a shift in the ocean circulation starting in 1991. A sensitivity analysis suggests that the source-sink reconstruction is robust to typical systematic and random errors in the ocean circulation model driving the particle drift simulations. The jellyfish analysis illustrates that new insights can be gained by studying structural changes in source-sink dynamics. The proposed approach is applicable for the spatial source-sink reconstruction of other species and even abiotic processes, such as sediment transport. PMID:24835251

Chen, Kun; Ciannelli, Lorenzo; Decker, Mary Beth; Ladd, Carol; Cheng, Wei; Zhou, Ziqian; Chan, Kung-Sik

2014-01-01

192

Resource Requirements of the Pacific Leatherback Turtle Population  

PubMed Central

The Pacific population of leatherback sea turtles (Dermochelys coriacea) has drastically declined in the last 25 years. This decline has been linked to incidental capture by fisheries, egg and meat harvesting, and recently, to climate variability and resource limitation. Here we couple growth rates with feeding experiments and food intake functions to estimate daily energy requirements of leatherbacks throughout their development. We then estimate mortality rates from available data, enabling us to raise food intake (energy requirements) of the individual to the population level. We place energy requirements in context of available resources (i.e., gelatinous zooplankton abundance). Estimated consumption rates suggest that a single leatherback will eat upward of 1000 metric tonnes (t) of jellyfish in its lifetime (range 924–1112) with the Pacific population consuming 2.1×106 t of jellyfish annually (range 1.0–3.7×106) equivalent to 4.2×108 megajoules (MJ) (range 2.0–7.4×108). Model estimates suggest 2–7 yr-old juveniles comprise the majority of the Pacific leatherback population biomass and account for most of the jellyfish consumption (1.1×106 t of jellyfish or 2.2×108 MJ per year). Leatherbacks are large gelatinous zooplanktivores with consumption to biomass ratios of 96 (up to 192 if feeding strictly on low energy density Cnidarians); they, therefore, have a large capacity to impact gelatinous zooplankton landscapes. Understanding the leatherback's needs for gelatinous zooplankton, versus the availability of these resources, can help us better assess population trends and the influence of climate induced resource limitations to reproductive output. PMID:23071518

Jones, T. Todd; Bostrom, Brian L.; Hastings, Mervin D.; Van Houtan, Kyle S.; Pauly, Daniel; Jones, David R.

2012-01-01

193

Ocean Life for Kids  

NSDL National Science Digital Library

This website provides a variety of photos and text to teach students about life in the oceans. Various animals discussed include fish, sharks, dolphins, octopus, starfish, eels, lobster and jellyfish. Students choose an animal to look at, view some facts about that animal, and then answer questions based on the information given. The objective is for young elementary students to be able to distinguish amoung types of ocean life and what makes them unique.

194

Characterization of fission yeast meiotic mutants based on live observation of meiotic prophase nuclear movement  

Microsoft Academic Search

.   We characterized four meiotic mutants of the fission yeast Schizosaccharomyces pombe by live observation of nuclear movement. Nuclei were stained with either the DNA-specific fluorescent dye Hoechst 33342 or\\u000a jellyfish green fluorescent protein (GFP) fused with the N-terminal portion of DNA polymerase ?. We first followed nuclear\\u000a dynamics in wild-type cells to determine the temporal sequence of meiotic events:

Yasushi Hiraoka; Da-Qiao Ding; Ayumu Yamamoto; Chihiro Tsutsumi; Yuji Chikashige

2000-01-01

195

Biota of a Pennsylvanian muddy coast: habitat within the Mazonian delta complex, northeast Illinois  

SciTech Connect

The Mazon Creek biota (Westphalian D) is composed of plants and animals from terrestrial fresh water and marginal marine habitats. Fossil animals, including jellyfish, worms, crustaceans, holothurians, insects, chordates, and problematica occur in sideritic concretions on spoilpiles of more than 100 abandoned coal mines in a five county region (Mazon Creek area) of northeast Illinois. These fossils record rapid burial and early diagenesis in a muddy, delta-influenced coastal setting submerged during marine transgression.

Baird, G.C.

1985-03-01

196

Ambient temperature catalyst-free light-induced preparation of macrocyclic aliphatic polyesters.  

PubMed

The light induced, catalyst-free ambient temperature preparation of macrocyclic aliphatic polyesters is pioneered. Based on the photo-induced Diels-Alder reaction of orthoquinodimethane and acrylate moieties, cyclic polyesters of high purity are readily synthesized. Considering the high tolerance to functional groups and the orthogonality of the ligation, the reported protocol can be easily transferred to a large range of polymers, complex topologies (tadpole, sun-shaped, jellyfish, etc.) and applications. PMID:24413149

Josse, Thomas; Altintas, Ozcan; Oehlenschlaeger, Kim K; Dubois, Philippe; Gerbaux, Pascal; Coulembier, Olivier; Barner-Kowollik, Christopher

2014-02-25

197

Growth, decay and burial compaction of Dickinsonia, an iconic Ediacaran fossil  

Microsoft Academic Search

Retallack, G.J., September, 2007. Growth, decay and burial compaction of Dickinsonia, an iconic Ediacaran fossil. Alcheringa 31, 215-240. ISSN 0311-5518.Dickinsonia is a Neoproterozoic, Ediacaran fossil, variously considered a polychaete, turbellarian or annelid worm, jellyfish, polyp, xenophyophoran protist, lichen or mushroom. Its preservation as unskeletonized impressions in quartz sandstones has been attributed to a Neoproterozoic regime of aerobic decay less effective

Gregory J. Retallack

2007-01-01

198

Flow cytometric and microscopic analysis of GFP-tagged Pseudomonas fluorescens bacteria  

Microsoft Academic Search

The gene encoding the green fluorescent protein (GFP) from the jellyfish Aequorea victoria was assembled into an expression cassette for bacteria by fusing it to the T7 gene10 ribosome binding site and the strong, constitutive promoter PpsbA from Amaranthus hybridus. By using Tn5-based transposon delivery systems, Pseudomonas fluorescens bacteria were chromosomally tagged with gfp. We demonstrate that expression of a

Riccardo Tombolini; Annika Unge; Mary Ellen Davey; Frans J de Bruijn; Janet K Jansson

1997-01-01

199

Photo-Induced Peptide Cleavage in the Green-to-Red Conversion of a Fluorescent Protein  

Microsoft Academic Search

Green fluorescent protein from the jellyfish (Aequorea GFP) and GFP-like proteins from coral species encode light-absorbing chromophores within their protein sequences. A coral fluorescent protein, Kaede, contains a tripeptide, His62-Tyr63-Gly64, which acts as a green chromophore that is photoconverted to red. Here, we present the structural basis for the green-to-red photoconversion. As in Aequorea GFP, a chromophore, 4-(p-hydroxybenzylidene)-5-imidazolinone, derived from

Hideaki Mizuno; Tapas Kumar Mal; Kit I. Tong; Ryoko Ando; Toshiaki Furuta; Mitsuhiko Ikura; Atsushi Miyawaki

2003-01-01

200

Resource requirements of the Pacific leatherback turtle population.  

PubMed

The Pacific population of leatherback sea turtles (Dermochelys coriacea) has drastically declined in the last 25 years. This decline has been linked to incidental capture by fisheries, egg and meat harvesting, and recently, to climate variability and resource limitation. Here we couple growth rates with feeding experiments and food intake functions to estimate daily energy requirements of leatherbacks throughout their development. We then estimate mortality rates from available data, enabling us to raise food intake (energy requirements) of the individual to the population level. We place energy requirements in context of available resources (i.e., gelatinous zooplankton abundance). Estimated consumption rates suggest that a single leatherback will eat upward of 1000 metric tonnes (t) of jellyfish in its lifetime (range 924-1112) with the Pacific population consuming 2.1×10(6) t of jellyfish annually (range 1.0-3.7×10(6)) equivalent to 4.2×10(8) megajoules (MJ) (range 2.0-7.4×10(8)). Model estimates suggest 2-7 yr-old juveniles comprise the majority of the Pacific leatherback population biomass and account for most of the jellyfish consumption (1.1×10(6) t of jellyfish or 2.2×10(8) MJ per year). Leatherbacks are large gelatinous zooplanktivores with consumption to biomass ratios of 96 (up to 192 if feeding strictly on low energy density Cnidarians); they, therefore, have a large capacity to impact gelatinous zooplankton landscapes. Understanding the leatherback's needs for gelatinous zooplankton, versus the availability of these resources, can help us better assess population trends and the influence of climate induced resource limitations to reproductive output. PMID:23071518

Jones, T Todd; Bostrom, Brian L; Hastings, Mervin D; Van Houtan, Kyle S; Pauly, Daniel; Jones, David R

2012-01-01

201

Water vs. Land  

NSDL National Science Digital Library

This activity, created to accompany the museum's Milstein Hall of Ocean Life, gives students a hands-on look at how some ocean creatures rely on buoyancy for external support. The activity starts with a class discussion in which students ponder how their lives would be different if they lived in water. Then, using plastic baggies filled with water to represent jellyfish, they examine how these creatures without "organic support" rely on buoyancy.

202

Use of Helper-Free Replication-Defective Simian Immunodeficiency Virus-Based Vectors To Study Macrophage and T Tropism: Evidence for Distinct Levels of Restriction in Primary Macrophages and a T-Cell Line  

Microsoft Academic Search

Cell tropism of human and simian immunodeficiency viruses (HIV and SIV, respectively) is governed in part by interactions between the viral envelope protein and the cellular receptors. However, there is evidence that envelope-host cell interactions also affect postentry steps in viral replication. We used a helper-free replication- defective SIV macaque (SIVmac)-based retroviral vector carrying the enhanced jellyfish green fluorescent protein

STEVE S. KIM; XUE JUAN YOU; MARY-ELIZABETH HARMON; JULIE OVERBAUGH; HUNG FAN

2001-01-01

203

Flexible margin kinematics and vortex formation of Aurelia aurita and Robojelly.  

PubMed

The development of a rowing jellyfish biomimetic robot termed as "Robojelly", has led to the discovery of a passive flexible flap located between the flexion point and bell margin on the Aurelia aurita. A comparative analysis of biomimetic robots showed that the presence of a passive flexible flap results in a significant increase in the swimming performance. In this work we further investigate this concept by developing varying flap geometries and comparing their kinematics with A. aurita. It was shown that the animal flap kinematics can be replicated with high fidelity using a passive structure and a flap with curved and tapered geometry gave the most biomimetic performance. A method for identifying the flap location was established by utilizing the bell curvature and the variation of curvature as a function of time. Flaps of constant cross-section and varying lengths were incorporated on the Robojelly to conduct a systematic study of the starting vortex circulation. Circulation was quantified using velocity field measurements obtained from planar Time Resolved Digital Particle Image Velocimetry (TRDPIV). The starting vortex circulation was scaled using a varying orifice model and a pitching panel model. The varying orifice model which has been traditionally considered as the better representation of jellyfish propulsion did not appear to capture the scaling of the starting vortex. In contrast, the pitching panel representation appeared to better scale the governing flow physics and revealed a strong dependence on the flap kinematics and geometry. The results suggest that an alternative description should be considered for rowing jellyfish propulsion, using a pitching panel method instead of the traditional varying orifice model. Finally, the results show the importance of incorporating the entire bell geometry as a function of time in modeling rowing jellyfish propulsion. PMID:24905025

Villanueva, Alex; Vlachos, Pavlos; Priya, Shashank

2014-01-01

204

The green fluorescent protein (GFP) as a vital screenable marker in rice transformation  

Microsoft Academic Search

An engineered green fluorescent protein (GFP) from the jellyfish Aequora victoria was used to develop a facile and rapid rice transformation system using particle bombardment of immature embryos. The mgfp4 gene under the control of the 35s Cauliflower Mosaic Virus promoter produced bright-green fluorescence easily detectable and screenable in rice tissue 12–22\\u000a days after bombardment. Visual screening of transformed rice

P. Vain; B. Worland; A. Kohli; J. W. Snape; P. Christou

1998-01-01

205

Biological Imaging Capability in the ABRS Facility on ISS  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the Advanced Biological Research System (ABRS) on the International Space Station (ISS) and its biological imaging capability. The ABRS is an environmental control chamber. It has two indpendently controlled Experiment Research Chambers (ERCs) with temperature, relative humidity and carbon dioxide controls. ABRS is a third generation plant growth system. Several experiments are reviewed, with particular interest in the use of Green Fluorescent Protein (GFP) a non-destructive plant stress reporting mechanism, naturally found in jellyfish.

Cox, David R.; Murdoch, T.; Regan, M. F.; Meshlberger, R. J.; Mortenson, T. E.; Albino, S. A.; Paul, A. L.; Ferl, R. J.

2010-01-01

206

Fast-swimming hydromedusae exploit velar kinematics to form an optimal vortex wake  

Microsoft Academic Search

Fast-swimming hydromedusan jellyfish possess a characteristic funnel-shaped velum at the exit of their oral cavity that interacts with the pulsed jets of water ejected during swimming motions. It has been previously assumed that the velum primarily serves to augment swimming thrust by constricting the ejected flow in order to produce higher jet velocities. This paper presents high-speed video and dye-flow

John O. Dabiri; Sean P. Colin; John H. Costello

2006-01-01

207

Flexible Margin Kinematics and Vortex Formation of Aurelia aurita and Robojelly  

PubMed Central

The development of a rowing jellyfish biomimetic robot termed as “Robojelly”, has led to the discovery of a passive flexible flap located between the flexion point and bell margin on the Aurelia aurita. A comparative analysis of biomimetic robots showed that the presence of a passive flexible flap results in a significant increase in the swimming performance. In this work we further investigate this concept by developing varying flap geometries and comparing their kinematics with A. aurita. It was shown that the animal flap kinematics can be replicated with high fidelity using a passive structure and a flap with curved and tapered geometry gave the most biomimetic performance. A method for identifying the flap location was established by utilizing the bell curvature and the variation of curvature as a function of time. Flaps of constant cross-section and varying lengths were incorporated on the Robojelly to conduct a systematic study of the starting vortex circulation. Circulation was quantified using velocity field measurements obtained from planar Time Resolved Digital Particle Image Velocimetry (TRDPIV). The starting vortex circulation was scaled using a varying orifice model and a pitching panel model. The varying orifice model which has been traditionally considered as the better representation of jellyfish propulsion did not appear to capture the scaling of the starting vortex. In contrast, the pitching panel representation appeared to better scale the governing flow physics and revealed a strong dependence on the flap kinematics and geometry. The results suggest that an alternative description should be considered for rowing jellyfish propulsion, using a pitching panel method instead of the traditional varying orifice model. Finally, the results show the importance of incorporating the entire bell geometry as a function of time in modeling rowing jellyfish propulsion. PMID:24905025

Villanueva, Alex; Vlachos, Pavlos; Priya, Shashank

2014-01-01

208

Role of Pax genes in eye evolution: a cnidarian PaxB gene uniting Pax2 and Pax6 functions.  

PubMed

PaxB from Tripedalia cystophora, a cubomedusan jellyfish possessing complex eyes (ocelli), was characterized. PaxB, the only Pax gene found in this cnidarian, is expressed in the larva, retina, lens, and statocyst. PaxB contains a Pax2/5/8-type paired domain and octapeptide, but a Pax6 prd-type homeodomain. Pax2/5/8-like properties of PaxB include a DNA binding specificity of the paired domain, activation and inhibitory domains, and the ability to rescue spa(pol), a Drosophila Pax2 eye mutant. Like Pax6, PaxB activates jellyfish crystallin and Drosophila rhodopsin rh6 promoters and induces small ectopic eyes in Drosophila. Pax6 has been considered a "master" control gene for eye development. Our data suggest that the ancestor of jellyfish PaxB, a PaxB-like protein, was the primordial Pax protein in eye evolution and that Pax6-like genes evolved in triploblasts after separation from Cnidaria, raising the possibility that cnidarian and sophisticated triploblastic eyes arose independently. PMID:14602077

Kozmik, Zbynek; Daube, Michael; Frei, Erich; Norman, Barbara; Kos, Lidia; Dishaw, Larry J; Noll, Markus; Piatigorsky, Joram

2003-11-01

209

Bio-inspired unmanned undersea vehicle  

NASA Astrophysics Data System (ADS)

Biological systems in ocean environment provide all the desired features required for design of unmanned undersea vehicles. We noticed the uniqueness and simplicity in the design of rowing medusa and have successfully demonstrated working prototypes of Aurelia Aurita. In this study, we demonstrate the effect of bell joints in reducing the contraction force required for deformation. The study is based on observations made for the sub-umbrella features of jellyfish. Artificial jellyfish unmanned undersea vehicle (UUV) was fabricated consisting of silicone as the matrix material and shape memory alloy (SMA) as the actuation material. UUV was characterized for its performance and tailored to achieve vertical motion. SMAs were selected for actuation material because they are simple current-driven device providing large strain and blocking force. However, electrical power requirements were found to be quite high in the underwater conditions. It was identified that by including "joints" in the structural material forming the bell, the overall power requirement can be reduced as it lowers the resistance to compression. An analytical model was developed that correlates the deformation achieved with the morphology of the joints. Experiments were conducted to characterize the effect of both joint shapes and structural materials on the motion. Results are compared with that of natural medusa gastrodermal lamella and analyzed using the theoretical model. By including the features inherently present in natural jellyfish, the required compression force was found to be decreased.

Smith, Colin F.; Priya, Shashank

2010-04-01

210

Effect of Sub-Lethal Exposure to Ultraviolet Radiation on the Escape Performance of Atlantic Cod Larvae (Gadus morhua)  

PubMed Central

The amount of ultraviolet (UV) radiation reaching the earth's surface has increased due to depletion of the ozone layer. Several studies have reported that UV radiation reduces survival of fish larvae. However, indirect and sub-lethal impacts of UV radiation on fish behavior have been given little consideration. We observed the escape performance of larval cod (24 dph, SL: 7.6±0.2 mm; 29 dph, SL: 8.2±0.3 mm) that had been exposed to sub-lethal levels of UV radiation vs. unexposed controls. Two predators were used (in separate experiments): two-spotted goby (Gobiusculus flavescens; a suction predator) and lion's mane jellyfish (Cyanea capillata; a “passive" ambush predator). Ten cod larvae were observed in the presence of a predator for 20 minutes using a digital video camera. Trials were replicated 4 times for goby and 5 times for jellyfish. Escape rate (total number of escapes/total number of attacks ×100), escape distance and the number of larvae remaining at the end of the experiment were measured. In the experiment with gobies, in the UV-treated larvae, both escape rate and escape distance (36%, 38±7.5 mm respectively) were significantly lower than those of control larvae (75%, 69±4.7 mm respectively). There was a significant difference in survival as well (UV: 35%, Control: 63%). No apparent escape response was observed, and survival rate was not significantly different, between treatments (UV: 66%, Control: 74%) in the experiment with jellyfish. We conclude that the effect and impact of exposure to sub-lethal levels of UV radiation on the escape performance of cod larvae depends on the type of predator. Our results also suggest that prediction of UV impacts on fish larvae based only on direct effects are underestimations. PMID:22536406

Fukunishi, Yuichi; Browman, Howard I.; Durif, Caroline M. F.; Bjelland, Reidun M.; Skiftesvik, Anne Berit

2012-01-01

211

Antarctica Part Two  

NSDL National Science Digital Library

In this video, Jonathan treks all the way to Antarctica to investigate life south of the polar circle. Along the way he dives in the majestic kelp forests of Patagonia, where crabs rule the sea floor. Once he arrives in Antarctica, his adventures continue. He swims with penguins, dives under an iceberg, meets a massive jellyfish 3 feet across, and has an incredible encounter with a Leopard seal, the apex predator of Antarctica. Part 2 finds Jonathan continuing his exploration of Antarctica including an encounter with a Leopard seal. This program won a New England Emmy Award! Please see the accompanying lesson plan for educational objectives, discussion points and classroom activities.

Productions, Jonathan B.

2011-06-06

212

Leatherback turtles: the menace of plastic.  

PubMed

The leatherback, Dermochelyscoriacea, is a large sea turtle that feeds primarily on jellyfish. Floating plastic garbage could be mistaken for such prey. Autopsy records of 408 leatherback turtles, spanning 123 years (1885-2007), were studied for the presence or absence of plastic in the GI tract. Plastic was reported in 34% of these cases. If only cases from our first report (1968) of plastic were considered, the figure was 37%. Blockage of the gut by plastic was mentioned in some accounts. These findings are discussed in the context of removal of top predators from poorly understood food chains. PMID:19135688

Mrosovsky, N; Ryan, Geraldine D; James, Michael C

2009-02-01

213

Molecular Expressions: Virtual Scanning Electron Microscopy  

NSDL National Science Digital Library

This Java applet allows users to interactively explore various specimens as they appear under a scanning electron microscope (SEM). Choose from a cockroach, pollen grain, a diatomic molecule, a gecko foot, a jellyfish, and more. Users first adjust the focus, contrast, and brightness of the specimen to optimize its appearance. Then they use a slider to incrementally increase the magnification up to 10,000x. It is part of a much larger collection of optics and microscopy materials developed at the National High Magnetic Field Laboratory at Florida State University.

Kunkel, Dennis; Davidson, Michael

2009-06-14

214

EvoD/Vo  

PubMed Central

Preface The genetic systems controlling body axis formation trace back as far as the ancestor of diploblasts (corals, hydra, and jellyfish) and triploblasts (bilaterians). Comparative molecular studies provide powerful tools for elucidating the origins of mechanisms for establishing the dorsal-ventral and anterior-posterior axes in bilaterians and reveal differences in the evolutionary pressures acting upon tissue patterning. In this review, we focus on the origins of nervous system patterning and discuss recent comparative genetic studies; these indicate the existence of an ancient molecular mechanism underlying nervous system organization that was probably already present in the bilaterian ancestor. PMID:18679435

Mizutani, Claudia Mieko; Bier, Ethan

2009-01-01

215

Evolutionary crossroads in developmental biology: Cnidaria  

PubMed Central

There is growing interest in the use of cnidarians (corals, sea anemones, jellyfish and hydroids) to investigate the evolution of key aspects of animal development, such as the formation of the third germ layer (mesoderm), the nervous system and the generation of bilaterality. The recent sequencing of the Nematostella and Hydra genomes, and the establishment of methods for manipulating gene expression, have inspired new research efforts using cnidarians. Here, we present the main features of cnidarian models and their advantages for research, and summarize key recent findings using these models that have informed our understanding of the evolution of the developmental processes underlying metazoan body plan formation. PMID:21389047

Technau, Ulrich; Steele, Robert E.

2011-01-01

216

Molecular Structure of Salinamide B  

NSDL National Science Digital Library

Salinamide B is produced by the marine bacterium Streptomyces, an actinomycete that has been isolated from the surface of the jellyfish Cassiopeia xamachana, collected from the Florida Keys. Salinamide B shows moderate antibiotic activity against Gram-positive bacteria and exhibits potent topical anti-inflammatory activity. The biosynthesis of salinamide is currently being studied with hopes of generating unnatural salinamide analogues, which would be used to further understand its anti-inflammatory properties. Salinamide is thought to be a possible contender in the treatment of some forms of arthritis.

2003-04-10

217

Using targeted variants of aequorin to measure Ca2+ levels in intracellular organelles.  

PubMed

Aequorin is a Ca(2+)-sensitive photoprotein isolated from the jellyfish Aequorea victoria. It is an ideal probe for measuring Ca(2+) concentration ([Ca(2+)]) in intracellular organelles because it can be modified to include specific targeting sequences. On the binding of Ca(2+) to three high-affinity sites in aequorin, an irreversible reaction occurs in which the prosthetic group coelenterazine is released and a photon is emitted. This protocol presents procedures for expressing, targeting, and reconstituting aequorin in intact and permeabilized mammalian cells and describes how to use this photoprotein to measure intracellular [Ca(2+)] in various subcellular compartments. PMID:24371314

Granatiero, Veronica; Patron, Maria; Tosatto, Anna; Merli, Giulia; Rizzuto, Rosario

2014-01-01

218

Australian orchids and the doctors they commemorate.  

PubMed

Botanical taxonomy is a repository of medical biographical information. Such botanical memorials include the names of some indigenous orchids of Australia. By searching reference texts and journals relating to Australian botany and Australian orchidology, as well as Australian and international medical and botanical biographical texts, I identified 30 orchids indigenous to Australia whose names commemorate doctors and other medical professionals. Of these, 24 have names that commemorate a total of 16 doctors who worked in Australia. The doctors and orchids I identified include: doctor-soldiers Richard Sanders Rogers (1862-1942), after whom the Rogers' Greenhood (Pterostylis rogersii) is named, and Robert Brown (1773-1858), after whom the Purple Enamel Orchid (Elythranthera brunonis) is named; navy surgeon Archibald Menzies (1754-1842), after whom the Hare Orchid (Leptoceras menziesii) is named; radiologist Hugo Flecker (1884-1957) after whom the Slender Sphinx Orchid (Cestichis fleckeri) is named; and general medical practitioner Hereward Leighton Kesteven (1881-1964), after whom the Kesteven's Orchid (Dendrobium kestevenii) is named. Biographic references in scientific names of plants comprise a select but important library of Australian medical history. Such botanical taxonomy commemorates, in an enduring manner, clinicians who have contributed to biology outside clinical practice. PMID:23330773

Pearn, John H

2013-01-21

219

Perfluoroalkyl contaminants in plasma of five sea turtle species: comparisons in concentration and potential health risks.  

PubMed

The authors compared blood plasma concentrations of 13 perfluoroalkyl contaminants (PFCs) in five sea turtle species with differing trophic levels. Wild sea turtles were blood sampled from the southeastern region of the United States, and plasma was analyzed using liquid chromatography tandem mass spectrometry. Mean concentrations of perfluorooctane sulfonate (PFOS), the predominant PFC, increased with trophic level from herbivorous greens (2.41 ng/g), jellyfish-eating leatherbacks (3.95 ng/g), omnivorous loggerheads (6.47 ng/g), to crab-eating Kemp's ridleys (15.7 ng/g). However, spongivorous hawksbills had surprisingly high concentrations of PFOS (11.9 ng/g) and other PFCs based on their trophic level. These baseline concentrations of biomagnifying PFCs demonstrate interesting species and geographical differences. The measured PFOS concentrations were compared with concentrations known to cause toxic effects in laboratory animals, and estimated margins of safety (EMOS) were calculated. Small EMOS (<100), suggestive of potential risk of adverse health effects, were observed for all five sea turtle species for immunosuppression. Estimated margins of safety less than 100 were also observed for liver, thyroid, and neurobehavorial effects for the more highly exposed species. These baseline concentrations and the preliminary EMOS exercise provide a better understanding of the potential health risks of PFCs for conservation managers to protect these threatened and endangered species. PMID:22447337

Keller, Jennifer M; Ngai, Lily; Braun McNeill, Joanne; Wood, Lawrence D; Stewart, Kelly R; O'Connell, Steven G; Kucklick, John R

2012-06-01

220

High-molecular weight protein toxins of marine invertebrates and their elaborate modes of action.  

PubMed

High-molecular weight protein toxins significantly contribute to envenomations by certain marine invertebrates, e.g., jellyfish and fire corals. Toxic proteins frequently evolved from enzymes meant to be employed primarily for digestive purposes. The cellular intermediates produced by such enzymatic activity, e.g., reactive oxygen species or lysophospholipids, rapidly and effectively mediate cell death by disrupting cellular integrity. Membrane integrity may also be disrupted by pore-forming toxins that do not exert inherent enzymatic activity. When targeted to specific pharmacologically relevant sites in tissues or cells of the natural enemy or prey, toxic enzymes or pore-forming toxins even may provoke fast and severe systemic reactions. Since toxin-encoding genes constitute "hot spots" of molecular evolution, continuous variation and acquirement of new pharmacological properties are guaranteed. This also makes individual properties and specificities of complex proteinaceous venoms highly diverse and inconstant. In the present chapter we portray high-molecular weight constituents of venoms present in box jellyfish, sea anemones, sea hares, fire corals and the crown-of-thorns starfish. The focus lies on the latest achievements in the attempt to elucidate their molecular modes of action. PMID:20358685

Butzke, Daniel; Luch, Andreas

2010-01-01

221

Stimulated bacterioplankton growth and selection for certain bacterial taxa in the vicinity of the ctenophore Mnemiopsis leidyi  

PubMed Central

Episodic blooms of voracious gelatinous zooplankton, such as the ctenophore Mnemiopsis leidyi, affect pools of inorganic nutrients and dissolved organic carbon by intensive grazing activities and mucus release. This will potentially influence bacterioplankton activity and community composition, at least at local scales; however, available studies on this are scarce. In the present study we examined effects of M. leidyi on bacterioplankton growth and composition in incubation experiments. Moreover, we examined community composition of bacteria associated with the surface and gut of M. leidyi. High release of ammonium and high bacterial growth was observed in the treatments with M. leidyi relative to controls. Deep 454 pyrosequencing of 16 S rRNA genes showed specific bacterial communities in treatments with M. leidyi as well as specific communities associated with M. leidyi tissue and gut. In particular, members of Flavobacteriaceae were associated with M. leidyi. Our study shows that M. leidyi influences bacterioplankton activity and community composition in the vicinity of the jellyfish. In particular during temporary aggregations of jellyfish, these local zones of high bacterial growth may contribute significantly to the spatial heterogeneity of bacterioplankton activity and community composition in the sea. PMID:22912629

Dinasquet, Julie; Granhag, Lena; Riemann, Lasse

2012-01-01

222

Retinoic acid X receptor in the diploblast, Tripedalia cystophora.  

PubMed

Nuclear hormone receptors comprise a characteristic family of transcription factors found in vertebrates, insects and nematodes. Here we show by cDNA and gene cloning that a Cnidarian, Tripedalia cystophora, possesses a retinoid receptor (jRXR) with remarkable homology to vertebrate retinoic acid X receptors (RXRs). Like vertebrate RXRs, jRXR binds 9-cis retinoic acid (Kd = 4 x 10(-10) M) and binds to the DNA sequence, PuGGTCA as a monomer in vitro. jRXR also heterodimerizes with Xenopus TR beta on a thyroid responsive element of a direct repeat separated by 4 bp. A jRXR binding half-site capable of interacting with (His6)jRXR fusion protein was identified in the promoters of three T. cystophora crystallin genes that are expressed highly in the eye lens of this jellyfish. Because crystallin gene expression is regulated by retionoid signaling in vertebrates, the jellyfish crystallin genes are candidate in vivo targets for jRXR. Finally, an antibody prepared against (His6)jRXR showed that full-length jRXR is expressed at all developmental stages of T. cystophora except the ephydra, where a smaller form replaces is. These data show that Cnidaria, a diploblastic phylum ancestral to the triploblastic invertebrate and subsequent vertebrate lineages, already have an RXR suggesting that RXR is an early component of the regulatory mechanisms of metazoa. PMID:9811819

Kostrouch, Z; Kostrouchova, M; Love, W; Jannini, E; Piatigorsky, J; Rall, J E

1998-11-10

223

Multiple Shaker potassium channels in a primitive metazoan.  

PubMed

Voltage-gated potassium channels are critical elements in providing functional diversity in nervous systems. The diversity of voltage-gated K+ channels in modern triploblastic metazoans (such as mollusks, arthropods and vertebrates) is provided primarily by four gene subfamilies (Shaker, Shal, Shab, and Shaw), but there has been no data from the ancient diploblastic metazoans until now. Diploblasts, represented by jellyfish and other coelenterates, arose during the first major metazoan radiation and are the most structurally primitive animals to have true nervous systems. By comparing the K+ channels of diploblasts and triploblasts, we may determine the fundamental set of K+ channels present in the first nervous systems. We now report the isolation of two Shaker subfamily cDNA clones, jShak1 and jShak2, from the hydrozoan jellyfish Polyorchis penicillatus (Phylum Cnidaria). JShak1 and jShak2 express transient outward currents in Xenopus oocytes most similar to Shaker currents from Drosophila in their rates of inactivation and recovery from inactivation. The finding of multiple Shaker subfamily genes is significant in that multiple Shaker genes also exist in mammals. In Drosophila, multiple Shaker channels are also produced, but by a mechanism of alternative splicing. Thus, the Shaker K+ channel subfamily had an established functional identity prior to the first major radiation of metazoans, and multiple forms of Shaker channels have been independently selected for in a wide range of metazoans. PMID:8613736

Jegla, T; Grigoriev, N; Gallin, W J; Salkoff, L; Spencer, A N

1995-12-01

224

Novel aplanatic designs for LED concentration  

NASA Astrophysics Data System (ADS)

Aplanats make great concentrators because of their near perfect imaging. Aplanatic conditions can be satisfied using two surface curves (generally mirrored surfaces) in two dimensions (see Figure 1) which are constructed by successive approximation to create a highly efficient concentrator for both concentration and illumination. For concentration purposes, having a two mirror system would be impossible because the front mirror would block incoming light (see figure 2) so the idea is to replace the front mirror with a "one-way" mirror. Light from a lower index can be transmitted, so if the aplanat surface is a higher index light is allowed to enter, and be trapped. In the Jellyfish design, TIR takes place except for light striking the surface within the range of critical angles. To combat that, a small area of reflective coating is applied to the central top part of the Jellyfish, where TIR fails (In the middle) to keep the light there from directly escaping (see figure 3). The design works in both forwards and reverse. Light entering can be focused to a collecter, or the collecter can be replaced with a light source to concentrate light out. In this case, LEDs are used for their highly efficienct properties.

Ricketts, Melissa; Winston, Roland; Jiang, Lun

2014-09-01

225

High-fidelity simulations of simple models of biomorphic aquatic locomotion  

NASA Astrophysics Data System (ADS)

Aquatic creatures self-propel and maneuver with an incredible diversity of mechanics, even at the moderate Reynolds numbers appropriate for bio-inspired autonomous vehicles. In this work, we explore simple two-dimensional abstractions of two such mechanisms---undulatory and jellyfish-like locomotion---effected by prescribed hinge motion in articulated rigid body systems. These mechanisms are explored using a high-fidelity Navier-Stokes solver based on the viscous vortex particle method, strongly coupled with the rigid-body dynamics of the system. Such coupling enables an investigation of untethered swimming and maneuvering, which is essential for developing reduced-order models for motion planning and control. In the case of undulatory locomotion, it is shown that swimming effectiveness depends on both the relative phase and amplitude of the oscillatory hinge motions. The optimal shape control at these finite Reynolds numbers is contrasted with optima found for zero Reynolds number and inviscid swimmers. The jellyfish motion is enabled by periodic contractions of the bell shape, adapted from experimentally-measured kinematics of medusan swimmers (Dabiri et al., J. Exp. Biol., 2005). The vortex formation processes, energy budgets and fluid forces are explored for their relationship with forward propulsion.

Eldredge, Jeff; Hector, Daniel; Wilson, Megan

2007-11-01

226

Assessment of space environmental factors by cytotoxicity bioassays  

NASA Astrophysics Data System (ADS)

Cellular bioassays for detection of cyto- and genotoxicity are useful in the risk assessment of space environmental factors. Such bioassay systems have the potential complement the physical detector systems used in space, insofar as they yield intrinsically biologically weighted measures of cellular responses. The experiment Cellular Responses to Radiation in Space (CERASP) has been selected by NASA/ESA to be performed on the International Space Station. It will supply basic information on the cellular response to radiation applied in microgravity. One of the biological endpoints under investigation will be survival reflected by radiation-dependent reduction of constitutive expression of the enhanced variant of green fluorescent protein (EGFP), originally isolated from the bioluminescent jellyfish Aequorea victoria. In this ground based study, the usefulness of this approach in comparison to standard techniques (colony forming ability test, MTT test) is shown.

Hellweg, Christine E.; Arenz, Andrea; Baumstark-Khan, Christa

2007-02-01

227

Bacterial Transformation with Green Fluorescent Protein  

NSDL National Science Digital Library

From the University of California, Davis, Partnership for Plant Genomics Education, this biotechnology laboratory is a five-day activity with bacterial transformations and green fluorescent protein. âÂÂIn this lab activity, students will attempt to cause a wild type strain of E. coli to incorporate and express a plasmid containing a gene that codes for a green fluorescent protein (GFP). The source of the GFP gene is the bioluminescent jellyfish Aequorea victoria. The plasmid also contains an ampicillin-resistance gene.â Several bioethics activities, readings, and diagrams help to illustrate and supplement the experiment. There are safety instructions, objectives, materials, preparation and clean-up notes, procedures, and questions for students to answer. ItâÂÂs a ready-to-use activity for biotechnology or plant genomics classrooms.

2008-12-09

228

Man-induced hydrological changes, metazooplankton communities and invasive species in the Berre Lagoon (Mediterranean Sea, France).  

PubMed

The Berre Lagoon has been under strong anthropogenic pressure since the early 1950s. The opening of the hydroelectric EDF power plant in 1966 led to large salinity drops. The zooplankton community was mainly composed of two common brackish species: Acartia tonsa and Brachionus plicatilis. Since 2006, European litigation has strongly constrained the input of freshwater, maintaining the salinity above 15. A study was performed between 2008 and 2010 to evaluate how these modifications have impacted the zooplankton community. Our results show that the community is more diverse and contains several coastal marine species (i.e., Centropages typicus, Paracalanus parvus and Acartia clausi). A. tonsa is still present but is less abundant, whereas B. plicatilis has completely disappeared. Strong predatory marine species, such as chaetognaths, the large conspicuous autochtonous jellyfish Aurelia aurita and the invasive ctenophore Mnemiopsis leidyi, are now very common as either seasonal or permanent features of the lagoon. PMID:22776776

Delpy, Floriane; Pagano, Marc; Blanchot, Jean; Carlotti, François; Thibault-Botha, Delphine

2012-09-01

229

Exceptionally preserved Late Ordovician biotas from Manitoba, Canada  

NASA Astrophysics Data System (ADS)

There are few body fossil biotas known from early Paleozoic accretionary shorelines, and very few examples of Ordovician soft-bodied assemblages. This study documents two recently discovered biotas from separate sedimentary basins in Manitoba, Canada, that provide unique information about tropical shoreline communities shortly before the Late Ordovician extinction event. Each site represents a distinct depositional environment, but they share biotic elements, including eurypterids, xiphosurids, and large problematic tubes. The William Lake biota, representing more restricted conditions, includes jellyfish that are among the best hydromedusan body fossils known. Rocks at the Airport Cove site, deposited under more open circulation, contain scolecodonts and noncalcified algae. These biotas have some parallels with the recently described Middle Ordovician Winneshiek Lagerstätte, but are also similar to some Late Silurian assemblages. Considered together, early Paleozoic marginal marine deposits are a rich but as yet poorly known source of paleobiodiversity data.

Young, Graham A.; Rudkin, David M.; Dobrzanski, Edward P.; Robson, Sean P.; Nowlan, Godfrey S.

2007-10-01

230

Genetically modified plants for tactical systems applications  

NASA Astrophysics Data System (ADS)

Plants are ubiquitous in the environment and have the ability to respond to their environment physiologically and through altered gene expression profiles (they cannot walk away). In addition, plant genetic transformation techniques and genomic information in plants are becoming increasingly advanced. We have been performing research to express the jellyfish green fluorescent protein (GFP) in plants. GFP emits green light when excited by blue or UV light. In addition, my group and collaborators have developed methods to detect GFP in plants by contact instruments and at a standoff. There are several tactical uses for this technology. Some obvious applications are using plants as sentinels for detecting biological and chemical warfare agents or their derivatives from a remote platform, as well as detecting explosives. Another tactical application is covert monitoring using individual plants. Different methods to detect GFP in transgenic plants will be discussed.

Stewart, C. Neal, Jr.

2002-08-01

231

Chimeric green fluorescent protein-aequorin as bioluminescent Ca2+ reporters at the single-cell level  

PubMed Central

Monitoring calcium fluxes in real time could help to understand the development, the plasticity, and the functioning of the central nervous system. In jellyfish, the chemiluminescent calcium binding aequorin protein is associated with the green fluorescent protein and a green bioluminescent signal is emitted upon Ca2+ stimulation. We decided to use this chemiluminescence resonance energy transfer between the two molecules. Calcium-sensitive bioluminescent reporter genes have been constructed by fusing green fluorescent protein and aequorin, resulting in much more light being emitted. Chemiluminescent and fluorescent activities of these fusion proteins have been assessed in mammalian cells. Cytosolic Ca2+ increases were imaged at the single-cell level with a cooled intensified charge-coupled device camera. This bifunctional reporter gene should allow the investigation of calcium activities in neuronal networks and in specific subcellular compartments in transgenic animals. PMID:10860991

Baubet, Valerie; Le Mouellic, Herve; Campbell, Anthony K.; Lucas-Meunier, Estelle; Fossier, Philippe; Brulet, Philippe

2000-01-01

232

Imaging of light emission from the expression of luciferases in living cells and organisms: a review.  

PubMed

Luciferases are enzymes that emit light in the presence of oxygen and a substrate (luciferin) and which have been used for real-time, low-light imaging of gene expression in cell cultures, individual cells, whole organisms, and transgenic organisms. Such luciferin-luciferase systems include, among others, the bacterial lux genes of terrestrial Photorhabdus luminescens and marine Vibrio harveyi bacteria, as well as eukaryotic luciferase luc and ruc genes from firefly species (Photinus) and the sea pansy (Renilla reniformis), respectively. In various vectors and in fusion constructs with other gene products such as green fluorescence protein (GFP; from the jellyfish Aequorea), luciferases have served as reporters in a number of promoter search and targeted gene expression experiments over the last two decades. Luciferase imaging has also been used to trace bacterial and viral infection in vivo and to visualize the proliferation of tumour cells in animal models. PMID:11816060

Greer, Lee F; Szalay, Aladar A

2002-01-01

233

Antispasmodic activity of beta-damascenone and E-phytol isolated from Ipomoea pes-caprae.  

PubMed

The crude extract (IPA) of the plant Ipomoea pes-caprae (L.) R. Br. has previously been shown to antagonize smooth muscle contractions induced by several agonists via a non-specific mechanism. Bioassay-guided fractionation of IPA resulted in isolation of the antispasmodically acting isoprenoids beta-damascenone and E-phytol. Their antispasmodic potencies were found to be in the same range as that of papaverine, a general spasmolytic agent. This effect was suggested to play a role in the previously observed anti-inflammatory activity of IPA by interfering with the contraction of endothelial cells. Severe vascular contraction has been shown to be involved in the dermatitis caused by toxic jellyfishes. It is possible that beta-damascenone and E-phytol, by interfering with the contraction of vascular smooth muscle cells, are partly responsible for the previously reported effectiveness of IPA in the treatment of such dermatitis. PMID:1620738

Pongprayoon, U; Baeckström, P; Jacobsson, U; Lindström, M; Bohlin, L

1992-02-01

234

A formulation for calculating the translational velocity of a vortex ring or pair.  

PubMed

Cephalopods, among other marine animals, use jet propulsion for swimming. A simple actuator is designed to loosely mimic pulsatile jet formation in squid and jellyfish. The actuator is comprised of a cavity with an oscillating diaphragm and an exit orifice. Periodic oscillation of the diaphragm results in the formation of an array of vortex rings and eventually could generate a periodic pulsatile jet. A general formulation for calculating the velocity of a steadily translating vortical structure in two-dimensional and axi-symmetric shear flows is presented. This technique is based on taking the variational derivative of an energetic function at its critical point. This technique is general, applicable to vortices in liquid and gas media, with no limitation on the relative size of the vortex core. The technique is then implemented to estimate the translational velocity of a vortex ring in a Helmholtz vortex ring generator. PMID:17671319

Mohseni, Kamran

2006-12-01

235

Chesapeake Bay Program: Field Guide  

NSDL National Science Digital Library

This site describes the biota of the Chesapeake Bay, including mammals, fish, reptiles, amphibians, and crabs and shellfish. Lower food web organisms described are plankton, benthos, Shipworm, Bristle Worm, Jellyfish, Red Beard Sponge, Sea Squirt, Comb Jellies, and the Ghost Anemone. The description of the flora is confined to bay grasses, which are also known as submerged aquatic vegetation (SAV). Birds described at this site include Bald Eagle, Bufflehead, Osprey, Great Blue Heron, Eastern Screech-Owl, Gulls, Ruddy Duck, Carolina Chickadee, Ruddy Turnstone, and the large group known as waterfowl. The site also includes a special section on invasive species, and provides links to publications, status and trends, and extensive databases that include water quality, living resources, point sources, modeling, and cross-cutting indicators.

236

Evolution of multicellular animals as deduced from 5S rRNA sequences: a possible early emergence of the Mesozoa.  

PubMed Central

The nucleotide sequences of 5S rRNA from a mesozoan Dicyema misakiense and three metazoan species, i.e., an acorn-worm Saccoglossus kowalevskii, a moss-animal Bugula neritina, and an octopus Octopus vulgaris have been determined. A phylogenic tree of multicellular animals has been constructed from 73 5S rRNA sequences available at present including those from the above four sequences. The tree suggests that the mesozoan is the most ancient multicellular animal identified so far, its emergence time being almost the same as that of flagellated or ciliated protozoans. The branching points of planarians and nematodes are a little later than that of the mesozoan but are clearly earlier than other metazoan groups including sponges and jellyfishes. Many metazoan groups seem to have diverged within a relatively short period. PMID:6539911

Ohama, T; Kumazaki, T; Hori, H; Osawa, S

1984-01-01

237

Human glucocorticoid receptor isoform beta: recent understanding of its potential implications in physiology and pathophysiology.  

PubMed

The human glucocorticoid receptor (GR) gene expresses two splicing isoforms alpha and beta through alternative use of specific exons 9alpha and 9beta. In contrast to the classic receptor GRalpha, which mediates most of the known actions of glucocorticoids, the functions of GRbeta have been largely unexplored. Owing to newly developed methods, for example microarrays and the jellyfish fluorescence proteins, we and others have recently revealed novel functions of GRbeta. Indeed, this enigmatic GR isoform influences positively and negatively the transcriptional activity of large subsets of genes, most of which are not responsive to glucocorticoids, in addition to its well-known dominant negative effect against GRalpha-mediated transcriptional activity. A recent report suggested that the "ligand-binding domain" of GRbeta is active, forming a functional ligand-binding pocket associated with the synthetic compound RU 486. In this review, we discuss the functions of GRbeta, its mechanisms of action, and its pathologic implications. PMID:19633971

Kino, Tomoshige; Su, Yan A; Chrousos, George P

2009-11-01

238

Rapid evolutionary radiation of marine zooplankton in peripheral environments  

PubMed Central

Populations of jellyfish, Mastigias sp., landlocked in tropical marine lakes during the Holocene, show extreme genetic isolation (0.74 ? ?ST ? 1.00), founder effects (genetic diversity: 0.000 ? ? ? 0.001), rapid morphological evolution, and behavioral adaptation. These results demonstrate incipient speciation in what we propose may be modern analogues of Plio-Pleistocene populations isolated in ocean basins by glacially lowered sea level and counterparts to modern marine populations isolated on archipelagos and other distant shores. Geographic isolation in novel environments, even if geologically brief, may contribute much to marine biodiversity because evolutionary rates in marine plankton can rival the most rapid speciation seen for limnetic species, such as cichlids and sticklebacks. Marine lakes present situations rare in their clarity for studying evolution in marine taxa. PMID:15964980

Dawson, Michael N; Hamner, William M.

2005-01-01

239

Amazing Jellies  

NSDL National Science Digital Library

Learners can select from three online interactives to learn more about sea creatures known as jellies (often mistakenly known as jellyfish). In "Blobs of Goo", learners explore the question "What is a Jelly?" and guess the features of jelly anatomy. In "Life Cycles", learners play a game and earn points to complete the life cycles of moon jellies. Finally, in "JellyTown", learners play a game in order to maintain the ecological balance in the ocean and/or town and observe the effects of pollution and ocean warming on jellies, their predators and prey. There are three game modes for various ages. Although this site supports the learning associated with an aquarium exhibit, a visit is not necessary to participate in these activities.

Aquarium, New E.; University, Northeastern

2011-01-01

240

Calcium biosensing with a sol-gel immobilized photoprotein.  

PubMed

Aequorin, the bioluminescent protein found in the jellyfish Aequorea sp., has been immobilized in a porous sol-gel glass environment. The luminescence from this protein is specifically triggered by the presence of calcium ions, thus offering exciting possibilities for the development of an optical biosensor for this cationic species. The luminescence emission spectrum has been measured from the aequorin protein after interaction with calcium ions. The intensity of the luminescence, measured at the peak maximum of 470 nm, for the encapsulated protein has been calibrated against calcium ion concentration. The characterization of the protein within the sol-gel matrix has been reported together with biosensing experiments using human sera and milk samples. The results suggest that the sol-gel encapsulated aequorin protein offers potential as a one shot bioluminescence based biosensor for the determination of calcium ions in such complex matrices. PMID:9008410

Blyth, D J; Poynter, S J; Russell, D A

1996-12-01

241

[Land and marine fauna constituting a threat for recreational divers in the tropics].  

PubMed

Due to intensively growing international tourism, increasing numbers of people leave for countries with hot climates, where various threats for human health and life exist. Besides climatic and sanitary conditions, a rich fauna, represented by predators and venomous animals, can be included. Based on available world literature and their own observations, the authors present the threats that a tourist can possibly encounter whilst relaxing on the beach or during recreational diving in tropical waters. When staying in water, a large threat is posed by marine fish of prey (sharks, barracuda, muraena), Cnidaria (jellyfish, corals, anemones) and venomous animals (fish, sea snakes). On land, on the other hand, a threat can be posed by venomous arthropods (scorpions, spiders) and Hymenoptera insects. The study presents the most important representatives of fauna present in coastal areas frequently visited by diving enthusiasts. Also, clinical image and conduct in the case of body injures are discussed. PMID:19112854

Korzeniewski, Krzysztof

2008-09-01

242

The Late Precambrian fossil Kimberella is a mollusc-like bilaterian organism  

NASA Astrophysics Data System (ADS)

The fossil Kimberella quadrata was originally described from late Precambrian rocks of southern Australia. Reconstructed as a jellyfish, it was later assigned to the cubozoans (`box jellies'), and has been cited as a clear instance of an extant animal lineage present before the Cambrian. Until recently, Kimberella was known only from Australia, with the exception of some questionable north Indian specimens. We now have over thirty-five specimens of this fossil from the Winter Coast of the White Sea in northern Russia. Our study of the new material does not support a cnidarian affinity. We reconstruct Kimberella as a bilaterally symmetrical, benthic animal with a non-mineralized, univalved shell, resembling a mollusc in many respects. This is important evidence for the existence of large triploblastic metazoans in the Precambrian and indicates that the origin of the higher groups of protostomes lies well back in the Precambrian.

Fedonkin, Mikhail A.; Waggoner, Benjamin M.

1997-08-01

243

Optical studies of dynamical processes in fluorescent proteins  

NASA Astrophysics Data System (ADS)

Green fluorescent protein (GFP) extracted from the bioluminescent jellyfish Aequorea Victoria[1] and its mutants are novel nanoscale systems, which have been shown to exhibit desirable linear and nonlinear optical properties[2]. In this paper, a combination of both linear and nonlinear optical spectroscopic techniques was used to investigate dynamical processes in fluorescent proteins in both aqueous solution and an organic polymer matrix. Experimental results were analyzed in terms of a Brownian oscillator model[3] and by comparison to computer simulations. [1] M. Chalfie, G. Euskirchen, W. W. Ward and D. C. Prasher, Science 263 (1994) 802. [2] Sean M. Kirkpatrick, Rajesh R. Naik, Morley O. Stone, J. Phys. Chem. B 105 (2001) 2867. [3] S. Mukamel, "Nonlinear Optical Spectroscopy", (Oxford University Press, New York, 1995) pp. 227.

Liebig, Carl; Dennis, William; Kirkpatrick, Sean; Naik, Rajesh; Stone, Morley

2002-03-01

244

Antarctica Part One  

NSDL National Science Digital Library

In this video, Jonathan treks all the way to Antarctica to investigate life south of the polar circle. Along the way he dives in the majestic kelp forests of Patagonia, where crabs rule the sea floor. Once he arrives in Antarctica, his adventures continue. He swims with penguins, dives under an iceberg, meets a massive jellyfish 3 feet wide, and has an incredible encounter with a Leopard seal, the apex predator of Antarctica. Part 1 finds Jonathan diving in Ushuaia, Patagonia in Argentina before boarding the ship to Antarctica, then he finally gets to Antarctica and meets some penguins! This program won a New England Emmy Award! Please see the accompanying lesson plan for educational objectives, discussion points and classroom activities.

Productions, Jonathan B.

2011-05-04

245

Fully resolved simulation of self-propulsion of aquatic organisms  

NASA Astrophysics Data System (ADS)

We present a computational approach for fully resolved simulation of self-propulsion of organisms through a fluid. Our implicit algorithm solves for the translational and rotational motion of the organism for prescribed deformation kinematics. In addition, the solution for the surrounding flow field is also obtained. The approach is easy to apply to the body forms of a variety of organisms. Our final goal is to use this computational tool to help in understanding the mechanisms of movement and its control in aquatic animals. In this abstract we present validation of this method for different organisms. To validate the method with respect to analytical solutions, we consider two cases: 1) a flagellum which propagates plane waves, and 2) a flagellum that propagates helical waves. To validate the method with respect to empirical measurements we consider data from two organisms: 1) jellyfish (data from John Dabiri at Caltech), and 2) zebrafish (data from Melina Hale at The University of Chicago).

Curet, Oscar M.; Alali, Ibrahim; Patankar, Neelesh A.; Maciver, Malcolm A.

2008-11-01

246

Do small swimmers mix the ocean?  

NASA Astrophysics Data System (ADS)

In this communication we address some hydrodynamic aspects of recently proposed drift mechanism of biogenic mixing in the ocean [K. Katija and J. O. Dabiri, Nature (London) 460, 624 (2009)10.1038/nature08207]. The relevance of the locomotion gait at various spatial scales with respect to the drift is discussed. A hydrodynamic scenario of the drift based on unsteady inertial propulsion, typical for most small marine organisms, is proposed. We estimate its effectiveness by taking into account interaction of a swimmer with the turbulent marine environment. Simple scaling arguments are derived to estimate the comparative role of drift-powered mixing with respect to the turbulence. The analysis indicates substantial biomixing effected by relatively small but numerous drifters, such as krill or jellyfish.

Leshansky, A. M.; Pismen, L. M.

2010-08-01

247

A Lagrangian approach to vortex identification in swimming and flying animal wakes.  

NASA Astrophysics Data System (ADS)

The fluid wakes of swimming and flying animals are generally time-dependent. The Eulerian velocity field, which can be measured by existing DPIV measurement techniques, does not directly indicate the flow geometry in this type of unsteady flows. In this study, a Lagrangian approach is developed to determine the Lagrangian Coherent Structures, which are physical boundaries separating flow regions with distinct dynamics, including vortices. The determination of morphology and kinematics of vortices is necessary in estimating time-dependent locomotive forces (Dabiri, J. Exp. Bio., 2006). It also provides information in studying fluid transport in animal swimming and flying. The application of the method is demonstrated by studying the wake of a bluegill sunfish pectoral fin and that of a free-swimming jellyfish.

Peng, Jifeng; Dabiri, John

2006-11-01

248

A vorticity-free approach to wake-based swimming/flying force estimation  

NASA Astrophysics Data System (ADS)

Traditional wake-based analyses of animal swimming and flying depend largely on knowledge of the vorticity field, which can be difficult or impossible to incorporate in the context of unsteady fluid-structure interactions. This talk will describe the development and application of a technique for estimating swimming/flying forces that does not require measurement of the vorticity field. The method is based on the identification of Lagrangian Coherent Structures in the wake, whose dynamics are governed by the theory for deformable bodies in potential flow (Peng and Dabiri, J. Exp. Biol. 2007). This paradigm for the analysis of unsteady fluid-structure interactions is integrated with existing DPIV measurement techniques to analyze medusan (jellyfish) swimming and the dynamics of the bluegill sunfish pectoral fin.

Dabiri, John O.; Peng, Jifeng

2006-11-01

249

Venom evolution through gene duplications.  

PubMed

Venoms contain highly complex mixtures that typically include hundreds of different components and have evolved independently in a diverse range of animals including platypuses, shrews, snakes, lizards, fishes, echinoderms, spiders, wasps, centipedes, sea snails, cephalopods, jellyfish and sea anemones. Many venom genes evolved through gene duplication. Gene duplication occurs in all domains of life and provides the raw substrate from which novel function arise. In this review, we focus on the role that gene duplication has played in the origin and diversification of venom genes. We outline the selective advantages of venom gene duplicates and the role that selection has played in the retention of these duplicates. We use toxin gene intermediates to help trace the evolution of toxin innovation. We also focus on other genomic processes, such as exon and domain duplications, in venom evolution. Finally, we conclude by focusing on the use of high throughput sequencing technology in understanding venom evolution. PMID:22285376

Wong, Emily S W; Belov, Katherine

2012-03-15

250

The use of aequorin and its variants for Ca2+ measurements.  

PubMed

Ca(2+)-sensitive photoproteins are ideal agents for measuring the Ca(2+) concentration ([Ca(2+)]) in intracellular organelles because they can be modified to include specific targeting sequences. Aequorin was the first Ca(2+)-sensitive photoprotein probe used to measure the [Ca(2+)] inside specific intracellular organelles in intact cells. Aequorin is a 22-kDa protein produced by the jellyfish Aequorea victoria. On the binding of Ca(2+) to three high-affinity sites in aequorin, an irreversible reaction occurs in which the prosthetic group is released and a photon is emitted. Aequorin has become widely used for intracellular Ca(2+) measurements because it offers many advantages: For example, it can be targeted with precision, functions over a wide range of [Ca(2+)], and shows low buffering capacity. In this article we describe the main characteristics of the aequorin probe and review the reasons why it is widely used to measure intracellular [Ca(2+)]. PMID:24371311

Granatiero, Veronica; Patron, Maria; Tosatto, Anna; Merli, Giulia; Rizzuto, Rosario

2014-01-01

251

Green fluorescent protein-like proteins in reef Anthozoa animals.  

PubMed

Green fluorescent protein (GFP) from the bioluminescent jellyfish Aequorea victoria has become an important tool in molecular and cellular biology as a transcriptional reporter, fusion tag, and biosensor. Most significantly, it encodes a chromophore intrinsically within its protein sequence, obviating the need for external substrates or cofactors and enabling the genetic encoding of strong fluorescence. Mutagenesis studies have generated GFP variants with new colors, improved fluorescence and other biochemical properties. In parallel, GFPs and GFP-like molecules have been cloned from other organisms, including the bioluminescent sea pansy Renilla reniformis and other non-bioluminescent Anthozoa animals. In the jellyfish and sea pansy, the GFPs are coupled to their chemoluminescence. Instead of emitting the blue light generated by aequorin and luciferase, the GFPs absorb their energy of primary emission and emit green light, which travels farther in the sea. In contrast, GFP-like proteins in reef Anthozoa are thought to play a role in photoprotection of their symbiotic zooxanthellae in shallow water; they transform absorbed UV radiation contained in sunlight into longer fluorescence wavelengths (Salih, A., Larkum, A., Cox, G., Kuhl, M., and Hoegh-Guldberg, O. 2000. Nature, 408: 850-853). In this review, I will describe both the biological and practical aspects of Anthozoan GFP-like proteins, many of which will be greatly improved in utility and commercially available before long. The ubiquity of these molecular tools makes it important to appreciate the interplay between sunlight and GFP-like proteins of Anthozoan animals, and to consider the optimal use of these unique proteins in biological studies. PMID:12502888

Miyawaki, Atsushi

2002-10-01

252

First observations of jelly-falls at the seafloor in a deep-sea fjord  

NASA Astrophysics Data System (ADS)

Faunal communities at the deep-sea floor mainly rely on the downward transport of particulate organic material for energy, which can come in many forms, ranging from phytodetritus to whale carcasses. Recently, studies have shown that the deep-sea floor may also be subsidized by fluxes of gelatinous material to the benthos. The deep-sea scyphozoan medusa Periphylla periphylla is common in many deep-sea fjords in Norway and recent investigations in Lurefjorden in western Norway suggest that the biomass of this jellyfish currently exceeds 50000 t here. To quantify the presence of dead P. periphylla jellyfish falls (hereafter termed jelly-falls) at the deep seafloor and the standing stock of carbon (C) and nitrogen (N) deposited on the seafloor by this species, we made photographic transects of the seafloor, using a 'Yo-Yo' camera system during an opportunistic sampling campaign in March 2011. Of 218 seafloor photographs taken, jelly-falls were present in five, which resulted in a total jelly-fall abundance of 1×10 -2 jelly-falls m -2 over the entire area surveyed. Summed over the entire area of seafloor photographed, 1×10 -2 jelly-falls m -2 was equivalent to a C- and N-biomass of 13 mg C m -2 and 2 mg N m -2. The contribution of each jelly-fall to the C- and N-amount of the sediment in the immediate vicinity of each fall (i.e. to sediment in each 3.02 m 2 image in which jelly-falls were observed) was estimated to be 568±84 mg C m -2 and 88±13 mg N m -2. The only megafaunal taxon observed around or on top of the jelly-falls was caridean shrimp (14±5 individuals jelly-fall -1), and shrimp abundance was significantly greater in photographs in which a jelly-fall was found (14±5 individuals image -1) compared to photographs in which no jelly-falls were observed (1.4±0.7 individuals image -1). These observations indicate that jelly-falls in this fjord can enhance the sedimentary C- and N-amount at the deep-sea floor and may provide nutrition to benthic and demersal faunas in this environment. However, organic enrichment from the jelly-falls found in this single sampling event and associated disturbance was highly localized.

Sweetman, Andrew K.; Chapman, Annelise

2011-12-01

253

Adhesion networks of cnidarians: a postgenomic view.  

PubMed

Cell-extracellular matrix (ECM) and cell-cell adhesion systems are fundamental to the multicellularity of metazoans. Members of phylum Cnidaria were classified historically by their radial symmetry as an outgroup to bilaterian animals. Experimental study of Hydra and jellyfish has fascinated zoologists for many years. Laboratory studies, based on dissection, biochemical isolations, or perturbations of the living organism, have identified the ECM layer of cnidarians (mesoglea) and its components as important determinants of stem cell properties, cell migration and differentiation, tissue morphogenesis, repair, and regeneration. Studies of the ultrastructure and functions of intercellular gap and septate junctions identified parallel roles for these structures in intercellular communication and morphogenesis. More recently, the sequenced genomes of sea anemone Nematostella vectensis, Hydra magnipapillata, and coral Acropora digitifera have opened up a new frame of reference for analyzing the cell-ECM and cell-cell adhesion molecules of cnidarians and examining their conservation with bilaterians. This chapter integrates a review of literature on the structure and functions of cell-ECM and cell-cell adhesion systems in cnidarians with current analyses of genome-encoded repertoires of adhesion molecules. The postgenomic perspective provides a fresh view on fundamental similarities between cnidarian and bilaterian animals and is impelling wider adoption of species from phylum Cnidaria as model organisms. PMID:24411175

Tucker, Richard P; Adams, Josephine C

2014-01-01

254

Ecological extinction and evolution in the brave new ocean  

PubMed Central

The great mass extinctions of the fossil record were a major creative force that provided entirely new kinds of opportunities for the subsequent explosive evolution and diversification of surviving clades. Today, the synergistic effects of human impacts are laying the groundwork for a comparably great Anthropocene mass extinction in the oceans with unknown ecological and evolutionary consequences. Synergistic effects of habitat destruction, overfishing, introduced species, warming, acidification, toxins, and massive runoff of nutrients are transforming once complex ecosystems like coral reefs and kelp forests into monotonous level bottoms, transforming clear and productive coastal seas into anoxic dead zones, and transforming complex food webs topped by big animals into simplified, microbially dominated ecosystems with boom and bust cycles of toxic dinoflagellate blooms, jellyfish, and disease. Rates of change are increasingly fast and nonlinear with sudden phase shifts to novel alternative community states. We can only guess at the kinds of organisms that will benefit from this mayhem that is radically altering the selective seascape far beyond the consequences of fishing or warming alone. The prospects are especially bleak for animals and plants compared with metabolically flexible microbes and algae. Halting and ultimately reversing these trends will require rapid and fundamental changes in fisheries, agricultural practice, and the emissions of greenhouse gases on a global scale. PMID:18695220

Jackson, Jeremy B. C.

2008-01-01

255

Viriditoxin regulates apoptosis and autophagy via mitotic catastrophe and microtubule formation in human prostate cancer cells.  

PubMed

Microtubule targeting chemicals are considered excellent antitumor drugs through their binding to tubulin, which affects the instability of microtubules resulting in arrest of cancer cells. The present study was designed to investigate the antitumor effects of viriditoxin (VDT) against human prostate cancer cells. VDT, isolated from Paecilomyces variotii fungus, which was derived from the jellyfish Nemopilema nomurai, offers a new approach for controlling resistant bacterial infections by blocking bacterial cell division proteins. VDT produced dose-dependent cytotoxicity against human prostate cancer cells. Treatment with VDT promoted both apoptosis and autophagy in LNCaP cells. Annexin V/FITC staining indicated that apoptosis occurred in VDT-treated LNCaP cells. DAPI staining revealed morphological changes in the cell nuclei indicative of mitotic catastrophe in LNCaP cells. VDT caused cell growth inhibition via G2/M phase arrest. Moreover, VDT also increased autophagic cell death in LNCaP cells by induction of several autophagy-related proteins such as LC3  II, Atg5, Atg7 and beclin-1 protein, which are essential for autophagy induction. These results were also confirmed by acridine orange staining. This study indicates that VDT could potentially be effective against prostate cancer by promoting multiple modes of growth arrest and cell death coupled with apoptosis and autophagy. PMID:25231051

Kundu, Soma; Kim, Tae Hyung; Yoon, Jung Hyun; Shin, Han-Seung; Lee, Jaewon; Jung, Jee H; Kim, Hyung Sik

2014-12-01

256

Proteome of Hydra Nematocyst*  

PubMed Central

Stinging cells or nematocytes of jellyfish and other cnidarians represent one of the most poisonous and sophisticated cellular inventions in animal evolution. This ancient cell type is unique in containing a giant secretory vesicle derived from the Golgi apparatus. The organelle structure within the vesicle comprises an elastically stretched capsule (nematocyst) to which a long tubule is attached. During exocytosis, the barbed part of the tubule is accelerated with >5 million g in <700 ns, enabling a harpoon-like discharge (Nüchter, T., Benoit, M., Engel, U., Ozbek, S., and Holstein, T. W. (2006) Curr. Biol. 16, R316–R318). Hitherto, the molecular components responsible for the organelle's biomechanical properties were largely unknown. Here, we describe the proteome of nematocysts from the freshwater polyp Hydra magnipapillata. Our analysis revealed an unexpectedly complex secretome of 410 proteins with venomous and lytic but also adhesive or fibrous properties. In particular, the insoluble fraction of the nematocyst represents a functional extracellular matrix structure of collagenous and elastic nature. This finding suggests an evolutionary scenario in which exocytic vesicles harboring a venomous secretome assembled a sophisticated predatory structure from extracellular matrix motif proteins. PMID:22291027

Balasubramanian, Prakash G.; Beckmann, Anna; Warnken, Uwe; Schnolzer, Martina; Schuler, Andreas; Bornberg-Bauer, Erich; Holstein, Thomas W.; Ozbek, Suat

2012-01-01

257

Trophic amplification of climate warming.  

PubMed

Ecosystems can alternate suddenly between contrasting persistent states due to internal processes or external drivers. It is important to understand the mechanisms by which these shifts occur, especially in exploited ecosystems. There have been several abrupt marine ecosystem shifts attributed either to fishing, recent climate change or a combination of these two drivers. We show that temperature has been an important driver of the trophodynamics of the North Sea, a heavily fished marine ecosystem, for nearly 50 years and that a recent pronounced change in temperature established a new ecosystem dynamic regime through a series of internal mechanisms. Using an end-to-end ecosystem approach that included primary producers, primary, secondary and tertiary consumers, and detritivores, we found that temperature modified the relationships among species through nonlinearities in the ecosystem involving ecological thresholds and trophic amplifications. Trophic amplification provides an alternative mechanism to positive feedback to drive an ecosystem towards a new dynamic regime, which in this case favours jellyfish in the plankton and decapods and detritivores in the benthos. Although overfishing is often held responsible for marine ecosystem degeneration, temperature can clearly bring about similar effects. Our results are relevant to ecosystem-based fisheries management (EBFM), seen as the way forward to manage exploited marine ecosystems. PMID:19740882

Kirby, Richard R; Beaugrand, Gregory

2009-12-01

258

Independent evolution of striated muscles in cnidarians and bilaterians  

PubMed Central

Striated muscles are present in bilaterian animals (e.g. vertebrates, insects, annelids) and some non-bilaterian eumetazoans (i.e. cnidarians and ctenophores). The striking ultrastructural similarity of striated muscles between these animal groups is thought to reflect a common evolutionary origin1, 2. Here we show that a muscle protein core set, including a Myosin type II Heavy Chain motor protein characteristic of striated muscles in vertebrates (MyHC-st), was already present in unicellular organisms before the origin of multicellular animals. Furthermore, myhc-st and myhc-non-muscle (myhc-nm) orthologues are expressed differentially in two sponges, compatible with the functional diversification of myhc paralogues before the origin of true muscles and the subsequent deployment of MyHC-st in fast-contracting smooth and striated muscle. Cnidarians and ctenophores possess myhc-st orthologues but lack crucial components of bilaterian striated muscles, such as troponin complex and titin genes, suggesting the convergent evolution of striated muscles. Consistently, jellyfish orthologues of a shared set of bilaterian z-disc proteins are not associated with striated muscles, but are instead expressed elsewhere or ubiquitously. The independent evolution of eumetazoan striated muscles through the addition of novel proteins to a pre-existing, ancestral contractile apparatus may serve as a paradigm for the evolution of complex animal cell types. PMID:22763458

Steinmetz, Patrick R.H.; Kraus, Johanna E.M.; Larroux, Claire; U. Hammel, Jorg; Amon-Hassenzahl, Annette; Houliston, Evelyn; Worheide, Gert; Nickel, Michael; Degnan, Bernard M.; Technau, Ulrich

2012-01-01

259

KAnalyze: a fast versatile pipelined K-mer toolkit  

PubMed Central

Motivation: Converting nucleotide sequences into short overlapping fragments of uniform length, k-mers, is a common step in many bioinformatics applications. While existing software packages count k-mers, few are optimized for speed, offer an application programming interface (API), a graphical interface or contain features that make it extensible and maintainable. We designed KAnalyze to compete with the fastest k-mer counters, to produce reliable output and to support future development efforts through well-architected, documented and testable code. Currently, KAnalyze can output k-mer counts in a sorted tab-delimited file or stream k-mers as they are read. KAnalyze can process large datasets with 2 GB of memory. This project is implemented in Java 7, and the command line interface (CLI) is designed to integrate into pipelines written in any language. Results: As a k-mer counter, KAnalyze outperforms Jellyfish, DSK and a pipeline built on Perl and Linux utilities. Through extensive unit and system testing, we have verified that KAnalyze produces the correct k-mer counts over multiple datasets and k-mer sizes. Availability and implementation: KAnalyze is available on SourceForge: https://sourceforge.net/projects/kanalyze/ Contact: fredrik.vannberg@biology.gatech.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:24642064

Audano, Peter; Vannberg, Fredrik

2014-01-01

260

Fluorescence in insects  

NASA Astrophysics Data System (ADS)

Fluorescent molecules are much in demand for biosensors, solar cells, LEDs and VCSEL diodes, therefore, considerable efforts have been expended in designing and tailoring fluorescence to specific technical applications. However, naturally occurring fluorescence of diverse types has been reported from a wide array of living organisms: most famously, the jellyfish Aequorea victoria, but also in over 100 species of coral and in the cuticle of scorpions, where it is the rule, rather than the exception. Despite the plethora of known insect species, comparatively few quantitative studies have been made of insect fluorescence. Because of the potential applications of natural fluorescence, studies in this field have relevance to both physics and biology. Therefore, in this paper, we review the literature on insect fluorescence, before documenting its occurrence in the longhorn beetles Sternotomis virescens, Sternotomis variabilis var. semi rufescens, Anoplophora elegans and Stellognatha maculata, the tiger beetles Cicindela maritima and Cicindela germanica and the weevil Pachyrrhynchus gemmatus purpureus. Optical features of insect fluorescence, including emitted wavelength, molecular ageing and naturally occurring combinations of fluorescence with bioluminescence and colour-producing structures are discussed.

Welch, Victoria L.; Van Hooijdonk, Eloise; Intrater, Nurit; Vigneron, Jean-Pol

2012-10-01

261

Rise characteristics of gas bubbles in a 2D rectangular column: VOF simulations vs experiments  

SciTech Connect

About five centuries ago, Leonardo da Vinci described the sinuous motion of gas bubbles rising in water. The authors have attempted to simulate the rise trajectories of bubbles of 4, 5, 7, 8, 9, 12, and 20 mm in diameter rising in a 2D rectangular column filled with water. The simulations were carried out using the volume-of-fluid (VOF) technique developed by Hirt and Nichols (J. Computational Physics, 39, 201--225 (1981)). To solve the Navier-Stokes equations of motion the authors used a commercial solver, CFX 4.1c of AEA Technology, UK. They developed their own bubble-tracking algorithm to capture sinuous bubble motions. The 4 and 5 mm bubbles show large lateral motions observed by Da Vinci. The 7, 8 and 9 mm bubble behave like jellyfish. The 12 mm bubble flaps its wings like a bird. The extent of lateral motion of the bubbles decreases with increasing bubble size. Bubbles larger than 20 mm in size assume a spherical cap form and simulations of the rise characteristics match experiments exactly. VOF simulations are powerful tools for a priori determination of the morphology and rise characteristics of bubbles rising in a liquid. Bubble-bubble interactions are also properly modeled by the VOF technique.

Krishna, R.; Baten, J.M. van

1999-10-01

262

[Intoxications specific to the Aquitaine region].  

PubMed

Some intoxications are more specifically linked to the Aquitaine region than to other regions of France, due to environmental circumstances (fauna, flora, climate) or traditional activities (gastronomy). Three types of intoxications are particular in this area. Pine processionary caterpillar envenomations (Thaumetopoea pityocampa), a Southern Europe pinewood parasite, are frequently encountered in the Landes' forest. They are responsible of ocular and/or skin lesions with urticaria or contact dermatitis, seldom associated with immediate IgE hypersensitivity. According to the south Atlantic coastal region geology and the marine streams, venomous marine animals are mainly located in Charente-Maritime for jellyfish, in Gironde and in Landes for weeverfish and in Atlantic Pyrenees for sea anemone. Usually not dangerous, first-aid workers treat most cases of these envenomations. Some endemic mushrooms (Tricholoma auratum) which grow on the dunes of the Atlantic coastal region, are usually considered as very good comestibles, but were recently responsible for serious intoxications: T.auratum was responsible of several cases of rhabdomyolysis, without neurological involvement, nor renal or hepatic lesion. Three deaths were notified. Animal studies confirmed the responsibility of the mushrooms. PMID:19375827

Bédry, R; Gromb, S

2009-07-01

263

[Aluminium content in foods with aluminium-containing food additives].  

PubMed

The aluminium (Al) content of 105 samples, including bakery products made with baking powder, agricultural products and seafoods treated with alum, was investigated. The amounts of Al detected were as follows (limit of quantification: 0.01 mg/g): 0.01-0.37 mg/g in 26 of 57 bakery products, 0.22-0.57 mg/g in 3 of 6 powder mixes, 0.01-0.05 mg/g in all three agricultural products examined, 0.03-0.90 mg/g in 4 of 6 seafood samples, 0.01-0.03 mg/g in 3 of 11 samples of instant noodles, 0.04-0.14 mg/g in 3 of 4 samples of vermicelli, 0.01 mg/g in 1 of 16 soybean products, but none in soybeans. Amounts equivalent to the PTWI of a 16 kg infant were detected in two samples of bakery products, two samples of powder mixes and one sample of salted jellyfish, if each sample was taken once a week. These results suggest that certain foods, depending on the product and the intake, might exceed the PTWI of children, especially infants. PMID:22450671

Ogimoto, Mami; Suzuki, Kumi; Kabashima, Junichiro; Nakazato, Mitsuo; Uematsu, Yoko

2012-01-01

264

Ring of Stellar Death  

NASA Technical Reports Server (NTRS)

This false-color image from NASA's Spitzer Space Telescope shows a dying star (center) surrounded by a cloud of glowing gas and dust. Thanks to Spitzer's dust-piercing infrared eyes, the new image also highlights a never-before-seen feature -- a giant ring of material (red) slightly offset from the cloud's core. This clumpy ring consists of material that was expelled from the aging star.

The star and its cloud halo constitute a 'planetary nebula' called NGC 246. When a star like our own Sun begins to run out of fuel, its core shrinks and heats up, boiling off the star's outer layers. Leftover material shoots outward, expanding in shells around the star. This ejected material is then bombarded with ultraviolet light from the central star's fiery surface, producing huge, glowing clouds -- planetary nebulas -- that look like giant jellyfish in space.

In this image, the expelled gases appear green, and the ring of expelled material appears red. Astronomers believe the ring is likely made of hydrogen molecules that were ejected from the star in the form of atoms, then cooled to make hydrogen pairs. The new data will help explain how planetary nebulas take shape, and how they nourish future generations of stars.

This image composite was taken on Dec. 6, 2003, by Spitzer's infrared array camera, and is composed of images obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

2004-01-01

265

Frequency tuning in animal locomotion.  

PubMed

In locomotion that involves repetitive motion of propulsive structures (arms, legs, fins, wings) there are resonant frequencies f(*) at which the energy consumption is a minimum. As animals need to change their speed, they can maintain this energy minimum by tuning their body resonances. We discuss the physical principles of frequency tuning, and how it relates to forces, damping, and oscillation amplitude. The resonant frequency of pendulum-type oscillators (e.g. swinging arms and legs) may be changed by varying the mass moment of inertia, or the vertical acceleration of the pendulum pivot. The frequency of elastic vibrations (e.g. the bell of a jellyfish) can be tuned with a non-linear modulus of elasticity: soft for low deflection amplitudes (low resonant frequency), and stiff for large displacements (high resonant frequency). Tuning of elastic oscillations can also be achieved by changing the effective length or cross-sectional area of the elastic members, or by allowing springs in parallel or in series to become active. We propose that swimming and flying animals generate oscillating propulsive forces from precisely placed shed vortices and that these tuned motions can only occur when vortex shedding and the simple harmonic motion of the elastic elements of the propulsive structures are in resonance. PMID:16403613

Ahlborn, Boye K; Blake, Robert W; Megill, William M

2006-01-01

266

Green fluorescent protein.  

PubMed

Several bioluminescent coelenterates use a secondary fluorescent protein, the green fluorescent protein (GFP), in an energy transfer reaction to produce green light. The most studied of these proteins have been the GFPs from the jellyfish Aequorea victoria and the sea pansy Renilla reniformis. Although the proteins from these organisms are not identical, they are thought to have the same chromophore, which is derived from the primary amino acid sequence of GFP. The differences are thought to be due to changes in the protein environment of the chromophore. Recent interest in these molecules has arisen from the cloning of the Aequorea gfp cDNA and the demonstration that its expression in the absence of other Aequorea proteins results in a fluorescent product. This demonstration indicated that GFP could be used as a marker of gene expression and protein localization in living and fixed tissues. Bacterial, plant and animal (including mammalian) cells all express GFP. The heterologous expression of the gfp cDNA has also meant that it could be mutated to produce proteins with different fluorescent properties. Variants with more intense fluorescence or alterations in the excitation and emission spectra have been produced. PMID:7480149

Chalfie, M

1995-10-01

267

Extraction of Renilla-type luciferin from the calcium-activated photoproteins aequorin, mnemiopsin, and berovin.  

PubMed

Photoproteins, which emit light in an oxygen-independent intramolecular reaction initiated by calcium ions, have been isolated from several bioluminescent organisms, including the hydrozoan jellyfish Aequorea and the ctenophore Mnemiopsis. The system of a related anthozoan coelenterate, the sea pansy Renilla reniformis, however, is oxygen dependent, requiring two organic components, luciferin and luciferase. Previously published indirect evidence indicates that photoproteins may contain a Renilla-type luciferin. We have now extracted in high yield a Renilla-type luciferin from three photoproteins, aequorin (45% yield), mnemiopsin (98% yield), and berovin (85% yield). Photoprotein luciferin, released from the holoprotein by mercaptoethanol treatment and separated from apo-photoprotein by gel filtration, no longer responds to calcium but now requires luciferase and O2 for light production. Photoprotein luciferin is identical to Renilla luciferin with respect to reaction kinetics and bioluminescence spectral distribution. In view of these results, the generally accepted hypothesis that the photoprotein chromophore is a protein-stabilized hydroperoxide of luciferin must be modified. We believe, instead, that the chromophore is free luciferin and that oxygen is bound as an oxygenated derivative of an amino-acid side chain of the protein. We propose the general term "coelenterate luciferin" to describe the light-producing chromophore from all bioluminescent coelenterates and ctenophores. PMID:241074

Ward, W W; Cormier, M J

1975-07-01

268

Observation of Structural Phase Transition in Ferroelectric Crystals Using Green Fluorescence Protein  

NASA Astrophysics Data System (ADS)

The Green Fluorescence Protein (GFP) of the jellyfish Aequorea Victoria has attracted widespread interest as a biomolecular marker. It has created many applications in a variety of systems ranging from cell biology to biomedicine. One important application of GFP fluorescence is the detection of structural transitions in biomolecules.In order to examine the sensitivity of the protein fluorescence to structural changes, we sequestered GFP in ferroelectric crystals such as Triglycine sulfate (TGS) and Rochelle salt (RS). TGS has a second order phase transition at 49 C while RS has two phase transitions at -18 and +24 C. The peak of the fluorescence spectrum changes from 510 nm in solution to 470 nm in the crystal indicating a shift of the two absorption bands in the protein upon crystallization. The fluorescence intensity of GFP in TGS decreases as the temperature of the crystal approaches T_C, while its spectrum in RS shows complex changes with temperature. The changes in the time-resolved data are similar to that of the steady state data. Our data show that the onset of structural phase transition in these crystals is clearly detectable from the spectral changes of this chromophore. Other applications of this protein in time-resolved solid state dynamics will be discussed.

Sedarous, Salah; Wessels, William

1998-03-01

269

NASA Workshop on Animal Gravity-Sensing Systems  

NASA Technical Reports Server (NTRS)

The opportunity for space flight has brought about the need for well-planned research programs that recognize the significance of space flight as a scientific research tool for advancing knowledge of life on Earth, and that utilize each flight opportunity to its fullest. For the first time in history, gravity can be almost completely eliminated. Thus, studies can be undertaken that will help to elucidate the importance of gravity to the normal functioning of living organisms, and to determine the effects microgravity may have on an organism. This workshop was convened to organize a plan for space research on animal gravity-sensing systems and the role that gravity plays in the development and normal functioning of these systems. Scientists working in the field of animal gravity-sensing systems use a wide variety of organisms in their research. The workshop presentations dealt with topics which ranged from the indirect gravity receptor of the water flea, Daphnia (whose antennal setae apparently act as current-sensing receptors as the animal moves up and down in water), through specialized statocyst structures found in jellyfish and gastropods, to the more complex vestibular systems that are characteristic of amphibians, avians, and mammals.

Corcoran, M. L. (editor)

1986-01-01

270

Colloquium paper: ecological extinction and evolution in the brave new ocean.  

PubMed

The great mass extinctions of the fossil record were a major creative force that provided entirely new kinds of opportunities for the subsequent explosive evolution and diversification of surviving clades. Today, the synergistic effects of human impacts are laying the groundwork for a comparably great Anthropocene mass extinction in the oceans with unknown ecological and evolutionary consequences. Synergistic effects of habitat destruction, overfishing, introduced species, warming, acidification, toxins, and massive runoff of nutrients are transforming once complex ecosystems like coral reefs and kelp forests into monotonous level bottoms, transforming clear and productive coastal seas into anoxic dead zones, and transforming complex food webs topped by big animals into simplified, microbially dominated ecosystems with boom and bust cycles of toxic dinoflagellate blooms, jellyfish, and disease. Rates of change are increasingly fast and nonlinear with sudden phase shifts to novel alternative community states. We can only guess at the kinds of organisms that will benefit from this mayhem that is radically altering the selective seascape far beyond the consequences of fishing or warming alone. The prospects are especially bleak for animals and plants compared with metabolically flexible microbes and algae. Halting and ultimately reversing these trends will require rapid and fundamental changes in fisheries, agricultural practice, and the emissions of greenhouse gases on a global scale. PMID:18695220

Jackson, Jeremy B C

2008-08-12

271

Aging and longevity in the simplest animals and the quest for immortality.  

PubMed

Here we review the examples of great longevity and potential immortality in the earliest animal types and contrast and compare these to humans and other higher animals. We start by discussing aging in single-celled organisms such as yeast and ciliates, and the idea of the immortal cell clone. Then we describe how these cell clones could become organized into colonies of different cell types that lead to multicellular animal life. We survey aging and longevity in all of the basal metazoan groups including ctenophores (comb jellies), sponges, placozoans, cnidarians (hydras, jellyfish, corals and sea anemones) and myxozoans. Then we move to the simplest bilaterian animals (with a head, three body cell layers, and bilateral symmetry), the two phyla of flatworms. A key determinant of longevity and immortality in most of these simple animals is the large numbers of pluripotent stem cells that underlie the remarkable abilities of these animals to regenerate and rejuvenate themselves. Finally, we discuss briefly the evolution of the higher bilaterians and how longevity was reduced and immortality lost due to attainment of greater body complexity and cell cycle strategies that protect these complex organisms from developing tumors. We also briefly consider how the evolution of multiple aging-related mechanisms/pathways hinders our ability to understand and modify the aging process in higher organisms. PMID:24910306

Petralia, Ronald S; Mattson, Mark P; Yao, Pamela J

2014-07-01

272

Improving the spectral analysis of fluorescence resonance energy transfer in live cells: Application to interferon receptors and Janus kinases  

PubMed Central

The observed Fluorescence Resonance Energy Transfer (FRET) between fluorescently labeled proteins varies in cells. To understand how this variation affects our interpretation of how proteins interact in cells, we developed a protocol that mathematically separates donor-independent and donor-dependent excitations of acceptor, determines the electromagnetic interaction of donors and acceptors, and quantifies the efficiency of the interaction of donors and acceptors. By analyzing large populations of cells, we found that misbalanced or insufficient expression of acceptor or donor as well as their inefficient or reversible interaction influenced FRET efficiency in vivo. Use of red-shifted donors and acceptors gave spectra with less endogenous fluorescence but produced lower FRET efficiency, possibly caused by reduced quenching of red-shifted fluorophores in cells. Additionally, cryptic interactions between jellyfish FPs artefactually increased the apparent FRET efficiency. Our protocol can distinguish specific and nonspecific protein interactions even within highly constrained environments as plasma membranes. Overall, accurate FRET estimations in cells or within complex environments can be obtained by a combination of proper data analysis, study of sufficient numbers of cells, and use of properly empirically developed fluorescent proteins. PMID:23796694

Krause, Christopher D.; Digioia, Gina; Izotova, Lara S.; Pestka, Sidney

2013-01-01

273

Supramolecular shape shifter: polymorphs of self-organized fullerene assemblies.  

PubMed

Studies of hierarchical supramolecular assemblies of a fullerene derivative bearing three hexadecyloxy chains (1) have been carried out in various conditions, such as different organic solvents, temperatures, and with ultrasonication. The dimensional control of the hierarchical supramolecular architectures from the fullerene derivative (1), such as spherical vesicles, fibers, nano-disks, and uncommon conical and flower-shaped assemblies, was previously achieved. Here, further morphologies such as microspheres, windmill-like sheets, baton-, maracas-, and jellyfish-like assemblies were discovered. Shape shifting of supramolecular assemblies was seen only in the case of the fullerene derivative (1). Reference derivatives bearing three eicosyloxy (2) and three dodecyloxy chains (3) never showed such polymorphs, however, these derivatives self-organized into microparticles with nano-flake outer surfaces and ultra-thin disks, respectively. The fullerene derivatives studied here formed interdigitated bilayer structures with different interspacing length. There are two essential intermolecular forces present due to fullerene or aliphatic chains. Fullerene moieties exhibit strong pi-pi interactions, while van der Waals interactions between aliphatic chains can be altered by variation of their length. Three hexadecyloxy chains at the fullerene moiety (1) were the most effective substitution pattern for stimulating supramolecular shape shifting. PMID:19441348

Nakanishi, Takashi; Wang, Jiaobing; Möhwald, Helmuth; Kurth, Dirk G; Michinobu, Tsuyoshi; Takeuchi, Masayuki; Ariga, Katsuhiko

2009-01-01

274

Thrust Characterization for Vortex Ring Thrusters  

NASA Astrophysics Data System (ADS)

Synthetic jets are zero net mass pulsatile jets that are commonly used in flow control applications in air. In these cases the natural resonant frequency of the actuators plays an important role. In this work we will present thrust characterization of vortex ring thrusters (VRTs) in liquid (equivalent of synthetic jets in liquid medium). VRTs design are motivated by pulsatile jet propulsion in squid and jellyfish. A prototype jet thruster was designed and build for this investigation. The effect of the actuation frequency and stroke ratio on the thrust level was experimentally studied. A simplified slug model was defined which predicted the thrust according to the momentum transfer. According to the model the thrust values for various frequencies converges to a single non-dimensionalized thrust, which is only a function of the stroke ratio. The accuracy of the model was defined in terms of a coefficient ? which related predicted thrust values to those measured experimentally. This coefficient was observed to be nearly unity for stroke ratios below the formation number of the jet, and for frequencies below critical cavitation frequencies. ? was seen to decrease (measured thrust drops below predicted thrust) with increasing frequency for all jets with stroke ratios above the formation number. The feasibility of using such a device in typical marine vehicles was tested by implementing the thruster in an unmanned underwater vehicle. The vehicle test-bed was operated in various dynamic maneuvers, including a simulated parallel park.

Krieg, Mike; Mohseni, Kamran

2007-11-01

275

Light-induced flickering of DsRed provides evidence for distinct and interconvertible fluorescent states.  

PubMed Central

Green fluorescent protein (GFP) from jellyfish Aequorea victoria, the powerful genetically encoded tag presently available in a variety of mutants featuring blue to yellow emission, has found a red-emitting counterpart. The recently cloned red fluorescent protein DsRed, isolated from Discosoma corals (), with its emission maximum at 583 nm, appears to be the long awaited tool for multi-color applications in fluorescence-based biological research. Studying the emission dynamics of DsRed by fluorescence correlation spectroscopy (FCS), it can be verified that this protein exhibits strong light-dependent flickering similar to what is observed in several yellow-shifted mutants of GFP. FCS data recorded at different intensities and excitation wavelengths suggest that DsRed appears under equilibrated conditions in at minimum three interconvertible states, apparently fluorescent with different excitation and emission properties. Light absorption induces transitions and/or cycling between these states on time scales of several tens to several hundreds of microseconds, dependent on excitation intensity. With increasing intensity, the emission maximum of the static fluorescence continuously shifts to the red, implying that at least one state emitting at longer wavelength is preferably populated at higher light levels. In close resemblance to GFP, this light-induced dynamic behavior implies that the chromophore is subject to conformational rearrangements upon population of the excited state. PMID:11509387

Malvezzi-Campeggi, F; Jahnz, M; Heinze, K G; Dittrich, P; Schwille, P

2001-01-01

276

Mistaken identity? Visual similarities of marine debris to natural prey items of sea turtles  

PubMed Central

Background There are two predominant hypotheses as to why animals ingest plastic: 1) they are opportunistic feeders, eating plastic when they encounter it, and 2) they eat plastic because it resembles prey items. To assess which hypothesis is most likely, we created a model sea turtle visual system and used it to analyse debris samples from beach surveys and from necropsied turtles. We investigated colour, contrast, and luminance of the debris items as they would appear to the turtle. We also incorporated measures of texture and translucency to determine which of the two hypotheses is more plausible as a driver of selectivity in green sea turtles. Results Turtles preferred more flexible and translucent items to what was available in the environment, lending support to the hypothesis that they prefer debris that resembles prey, particularly jellyfish. They also ate fewer blue items, suggesting that such items may be less conspicuous against the background of open water where they forage. Conclusions Using visual modelling we determined the characteristics that drive ingestion of marine debris by sea turtles, from the point of view of the turtles themselves. This technique can be utilized to determine debris preferences of other visual predators, and help to more effectively focus management or remediation actions. PMID:24886170

2014-01-01

277

Does prey size matter? Novel observations of feeding in the leatherback turtle (Dermochelys coriacea) allow a test of predator-prey size relationships.  

PubMed

Optimal foraging models predict that large predators should concentrate on large prey in order to maximize their net gain of energy intake. Here, we show that the largest species of sea turtle, Dermochelys coriacea, does not strictly adhere to this general pattern. Field observations combined with a theoretical model suggest that a 300 kg leatherback turtle would meet its energetic requirements by feeding for 3-4 h a day on 4 g jellyfish, but only if prey were aggregated in high-density patches. Therefore, prey abundance rather than prey size may, in some cases, be the overriding parameter for foraging leatherbacks. This is a classic example where the presence of small prey in the diet of a large marine predator may reflect profitable foraging decisions if the relatively low energy intake per small individual prey is offset by high encounter rates and minimal capture and handling costs. This study provides, to our knowledge, the first quantitative estimates of intake rate for this species. PMID:22090203

Fossette, Sabrina; Gleiss, Adrian C; Casey, James P; Lewis, Andrew R; Hays, Graeme C

2012-06-23

278

The vascular endothelial growth factor (VEGF) family: angiogenic factors in health and disease  

PubMed Central

Vascular endothelial growth factors (VEGFs) are a family of secreted polypeptides with a highly conserved receptor-binding cystine-knot structure similar to that of the platelet-derived growth factors. VEGF-A, the founding member of the family, is highly conserved between animals as evolutionarily distant as fish and mammals. In vertebrates, VEGFs act through a family of cognate receptor kinases in endothelial cells to stimulate blood-vessel formation. VEGF-A has important roles in mammalian vascular development and in diseases involving abnormal growth of blood vessels; other VEGFs are also involved in the development of lymphatic vessels and disease-related angiogenesis. Invertebrate homologs of VEGFs and VEGF receptors have been identified in fly, nematode and jellyfish, where they function in developmental cell migration and neurogenesis. The existence of VEGF-like molecules and their receptors in simple invertebrates without a vascular system indicates that this family of growth factors emerged at a very early stage in the evolution of multicellular organisms to mediate primordial developmental functions. PMID:15693956

Holmes, David IR; Zachary, Ian

2005-01-01

279

An endogenous green fluorescent protein-photoprotein pair in Clytia hemisphaerica eggs shows co-targeting to mitochondria and efficient bioluminescence energy transfer  

PubMed Central

Green fluorescent proteins (GFPs) and calcium-activated photoproteins of the aequorin/clytin family, now widely used as research tools, were originally isolated from the hydrozoan jellyfish Aequora victoria. It is known that bioluminescence resonance energy transfer (BRET) is possible between these proteins to generate flashes of green light, but the native function and significance of this phenomenon is unclear. Using the hydrozoan Clytia hemisphaerica, we characterized differential expression of three clytin and four GFP genes in distinct tissues at larva, medusa and polyp stages, corresponding to the major in vivo sites of bioluminescence (medusa tentacles and eggs) and fluorescence (these sites plus medusa manubrium, gonad and larval ectoderms). Potential physiological functions at these sites include UV protection of stem cells for fluorescence alone, and prey attraction and camouflaging counter-illumination for bioluminescence. Remarkably, the clytin2 and GFP2 proteins, co-expressed in eggs, show particularly efficient BRET and co-localize to mitochondria, owing to parallel acquisition by the two genes of mitochondrial targeting sequences during hydrozoan evolution. Overall, our results indicate that endogenous GFPs and photoproteins can play diverse roles even within one species and provide a striking and novel example of protein coevolution, which could have facilitated efficient or brighter BRET flashes through mitochondrial compartmentalization. PMID:24718596

Fourrage, Cecile; Swann, Karl; Gonzalez Garcia, Jose Raul; Campbell, Anthony K.; Houliston, Evelyn

2014-01-01

280

Bioinspired affinity DNA polymers on nanoparticles for drug sequestration and detoxification.  

PubMed

Nanomaterials with the ability of sequestering target molecules hold great potential for a variety of applications. To ensure the stable sequestration, most of these nanomaterials have been traditionally designed with a clear boundary or compact structures and behave as closed systems. While this feature is beneficial to applications such as drug delivery, it may pose a challenge to applications where fast molecular transport from the environment to nanomaterials is critical. Thus, this study was aimed at exploring a nanomaterial with affinity DNA polymers and nanoparticles as an open system with function similar to jellyfish tentacles in sequestering target molecules from surroundings. The results show that this nanomaterial can effectively and rapidly sequester both small molecule drugs and large molecule biologics and resultantly mitigate their biological effects. Thus, this nanomaterial holds potential as a universal nanoscale antidote for drug removal and detoxification. While this nanomaterial was evaluated by using drug removal and detoxification as a model, the synthesis of periodically oriented affinity polymers on a nanoparticle with the capability of sequestering target molecules may be tuned for broad applications such as separation, sensing, imaging and drug delivery. PMID:25176063

Chen, Niancao; Huang, Yike; Wang, Yong

2014-12-01

281

Dietary Exposure to Aluminium and Health Risk Assessment in the Residents of Shenzhen, China  

PubMed Central

Although there are great changes of dietary in the past few decades in China, few are known about the aluminium exposure in Chinese diet. The aim of this study is to systematically evaluate the dietary aluminium intake level in residents of Shenzhen, China. A total of 853 persons from 244 household were investigated their diet by three days food records. Finally, 149 kinds of foods in 17 food groups were selected to be the most consumed foods. From them, 1399 food samples were collected from market to test aluminium concentration. High aluminium levels were found in jellyfish (median, 527.5 mg/kg), fried twisted cruller (median, 466.0 mg/kg), shell (median, 107.1 mg/kg). The Shenzhen residents' average dietary aluminium exposure was estimated at 1.263 mg/kg bw/week which is lower than the PTWI (provisional tolerable weekly intake). But 0–2 and 3–13 age groups have the highest aluminium intake exceeding the PTWI (3.356 mg/kg bw/week and 3.248 mg/kg bw/week) than other age groups. And the main dietary aluminium exposure sources are fried twisted cruller, leaf vegetables and bean products. Our study suggested that even three decades rapid economy development, children in Shenzhen still have high dietary aluminium exposure risk. How to control high dietary aluminium exposure still is a great public health challenge in Shenzhen, China. PMID:24594670

Yang, Mei; Jiang, Lixin; Huang, Huiping; Zeng, Shengbo; Qiu, Fen; Yu, Miao; Li, Xiaorong; Wei, Sheng

2014-01-01

282

Investigating the origins of triploblasty: 'mesodermal' gene expression in a diploblastic animal, the sea anemone Nematostella vectensis (phylum, Cnidaria; class, Anthozoa).  

PubMed

Mesoderm played a crucial role in the radiation of the triploblastic Bilateria, permitting the evolution of larger and more complex body plans than in the diploblastic, non-bilaterian animals. The sea anemone Nematostella is a non-bilaterian animal, a member of the phylum Cnidaria. The phylum Cnidaria (sea anemones, corals, hydras and jellyfish) is the likely sister group of the triploblastic Bilateria. Cnidarians are generally regarded as diploblastic animals, possessing endoderm and ectoderm, but lacking mesoderm. To investigate the origin of triploblasty, we studied the developmental expression of seven genes from Nematostella whose bilaterian homologs are implicated in mesodermal specification and the differentiation of mesodermal cell types (twist, snailA, snailB, forkhead, mef2, a GATA transcription factor and a LIM transcription factor). Except for mef2, the expression of these genes is largely restricted to the endodermal layer, the gastrodermis. mef2 is restricted to the ectoderm. The temporal and spatial expression of these 'mesoderm' genes suggests that they may play a role in germ layer specification. Furthermore, the predominantly endodermal expression of these genes reinforces the hypothesis that the mesoderm and endoderm of triploblastic animals could be derived from the endoderm of a diploblastic ancestor. Alternatively, we consider the possibility that the diploblastic condition of cnidarians is a secondary simplification, derived from an ancestral condition of triploblasty. PMID:15128674

Martindale, Mark Q; Pang, Kevin; Finnerty, John R

2004-05-01

283

Characterization of the Core Elements of the NF-?B Signaling Pathway of the Sea Anemone Nematostella vectensis ? ‡  

PubMed Central

The sea anemone Nematostella vectensis is the leading developmental and genomic model for the phylum Cnidaria, which includes anemones, hydras, jellyfish, and corals. In insects and vertebrates, the NF-?B pathway is required for cellular and organismal responses to various stresses, including pathogens and chemicals, as well as for several developmental processes. Herein, we have characterized proteins that comprise the core NF-?B pathway in Nematostella, including homologs of NF-?B, I?B, Bcl-3, and I?B kinase (IKK). We show that N. vectensis NF-?B (Nv-NF-?B) can bind to ?B sites and activate transcription of reporter genes containing multimeric ?B sites or the Nv-I?B promoter. Both Nv-I?B and Nv-Bcl-3 interact with Nv-NF-?B and block its ability to activate reporter gene expression. Nv-IKK is most similar to human IKK?/TBK kinases and, in vitro, can phosphorylate Ser47 of Nv-I?B. Nv-NF-?B is expressed in a subset of ectodermal cells in juvenile and adult Nematostella anemones. A bioinformatic analysis suggests that homologs of many mammalian NF-?B target genes are targets for Nv-NF-?B, including genes involved in apoptosis and responses to organic compounds and endogenous stimuli. These results indicate that NF-?B pathway proteins in Nematostella are similar to their vertebrate homologs, and these results also provide a framework for understanding the evolutionary origins of NF-?B signaling. PMID:21189285

Wolenski, Francis S.; Garbati, Michael R.; Lubinski, Tristan J.; Traylor-Knowles, Nikki; Dresselhaus, Erica; Stefanik, Derek J.; Goucher, Haley; Finnerty, John R.; Gilmore, Thomas D.

2011-01-01

284

Complex functions of Mef2 splice variants in the differentiation of endoderm and of a neuronal cell type in a sea anemone.  

PubMed

In triploblastic animals, mesoderm gives rise to many tissues and organs, including muscle. By contrast, the representatives of the diploblastic phylum Cnidaria (corals, sea anemones, jellyfish and hydroids) lack mesoderm but possess muscle. In vertebrates and insects, the transcription factor Mef2 plays a pivotal role in muscle differentiation; however, it is also an important regulator of neuron differentiation and survival. In the sea anemone Nematostella vectensis, an organism that lacks mesoderm but has muscles and neurons, Mef2 (Nvmef2) has been reported in single ectodermal cells of likely neural origin. To our surprise, we found that Nvmef2 is alternatively spliced, forming differentially expressed variants. Using morpholino-mediated knockdown and mRNA injection, we demonstrate that specific splice variants of Nvmef2 are required for the proliferation and differentiation of endodermal cells and for the development of ectodermal nematocytes, a neuronal cell type. Moreover, we identified a small conserved motif in the transactivation domain that is crucially involved in the endodermal function of Nvmef2. The identification of a crucial and conserved motif in the transactivation domain predicts a similarly important role in vertebrate Mef2 function. This is the first functional study of a determinant of several mesodermal derivatives in a diploblastic animal. Our data suggest that the involvement of alternative splice variants of Mef2 in endomesoderm and neuron differentiation predates the cnidarian-bilaterian split. PMID:22007131

Genikhovich, Grigory; Technau, Ulrich

2011-11-01

285

Chemical nature of the light emitter of the Aequorea green fluorescent protein  

PubMed Central

The jellyfish Aequorea victoria possesses in the margin of its umbrella a green fluorescent protein (GFP, 27 kDa) that serves as the ultimate light emitter in the bioluminescence reaction of the animal. The protein is made up of 238 amino acid residues in a single polypeptide chain and produces a greenish fluorescence (?max = 508 nm) when irradiated with long ultraviolet light. The fluorescence is due to the presence of a chromophore consisting of an imidazolone ring, formed by a post-translational modification of the tripeptide -Ser65-Tyr66-Gly67-. GFP has been used extensively as a reporter protein for monitoring gene expression in eukaryotic and prokaryotic cells, but relatively little is known about the chemical mechanism by which fluorescence is produced. To obtain a better understanding of this problem, we studied a peptide fragment of GFP bearing the chromophore and a synthetic model compound of the chromophore. The results indicate that the GFP chromophore consists of an imidazolone ring structure and that the light emitter is the singlet excited state of the phenolate anion of the chromophore. Further, the light emission is highly dependent on the microenvironment around the chromophore and that inhibition of isomerization of the exo-methylene double bond of the chromophore accounts for its efficient light emission. PMID:8942983

Niwa, Haruki; Inouye, Satoshi; Hirano, Takashi; Matsuno, Tatsuki; Kojima, Satoshi; Kubota, Masayuki; Ohashi, Mamoru; Tsuji, Frederick I.

1996-01-01

286

Chemical nature of the light emitter of the Aequorea green fluorescent protein.  

PubMed

The jellyfish Aequorea victoria possesses in the margin of its umbrella a green fluorescent protein (GFP, 27 kDa) that serves as the ultimate light emitter in the bioluminescence reaction of the animal. The protein is made up of 238 amino acid residues in a single polypeptide chain and produces a greenish fluorescence (lambda max = 508 nm) when irradiated with long ultraviolet light. The fluorescence is due to the presence of a chromophore consisting of an imidazolone ring, formed by a post-translational modification of the tripeptide -Ser65-Tyr66-Gly67-. GFP has been used extensively as a reporter protein for monitoring gene expression in eukaryotic and prokaryotic cells, but relatively little is known about the chemical mechanism by which fluorescence is produced. To obtain a better understanding of this problem, we studied a peptide fragment of GFP bearing the chromophore and a synthetic model compound of the chromophore. The results indicate that the GFP chromophore consists of an imidazolone ring structure and that the light emitter is the singlet excited state of the phenolate anion of the chromophore. Further, the light emission is highly dependent on the microenvironment around the chromophore and that inhibition of isomerization of the exo-methylene double bond of the chromophore accounts for its efficient light emission. PMID:8942983

Niwa, H; Inouye, S; Hirano, T; Matsuno, T; Kojima, S; Kubota, M; Ohashi, M; Tsuji, F I

1996-11-26

287

Biomimetic and live medusae reveal the mechanistic advantages of a flexible bell margin.  

PubMed

Flexible bell margins are characteristic components of rowing medusan morphologies and are expected to contribute towards their high propulsive efficiency. However, the mechanistic basis of thrust augmentation by flexible propulsors remained unresolved, so the impact of bell margin flexibility on medusan swimming has also remained unresolved. We used biomimetic robotic jellyfish vehicles to elucidate that propulsive thrust enhancement by flexible medusan bell margins relies upon fluid dynamic interactions between entrained flows at the inflexion point of the exumbrella and flows expelled from under the bell. Coalescence of flows from these two regions resulted in enhanced fluid circulation and, therefore, thrust augmentation for flexible margins of both medusan vehicles and living medusae. Using particle image velocimetry (PIV) data we estimated pressure fields to demonstrate a mechanistic basis of enhanced flows associated with the flexible bell margin. Performance of vehicles with flexible margins was further enhanced by vortex interactions that occur during bell expansion. Hydrodynamic and performance similarities between robotic vehicles and live animals demonstrated that the propulsive advantages of flexible margins found in nature can be emulated by human-engineered propulsors. Although medusae are simple animal models for description of this process, these results may contribute towards understanding the performance of flexible margins among other animal lineages. PMID:23145016

Colin, Sean P; Costello, John H; Dabiri, John O; Villanueva, Alex; Blottman, John B; Gemmell, Brad J; Priya, Shashank

2012-01-01

288

An algorithm to estimate unsteady and quasi-steady pressure fields from velocity field measurements.  

PubMed

We describe and characterize a method for estimating the pressure field corresponding to velocity field measurements such as those obtained by using particle image velocimetry. The pressure gradient is estimated from a time series of velocity fields for unsteady calculations or from a single velocity field for quasi-steady calculations. The corresponding pressure field is determined based on median polling of several integration paths through the pressure gradient field in order to reduce the effect of measurement errors that accumulate along individual integration paths. Integration paths are restricted to the nodes of the measured velocity field, thereby eliminating the need for measurement interpolation during this step and significantly reducing the computational cost of the algorithm relative to previous approaches. The method is validated by using numerically simulated flow past a stationary, two-dimensional bluff body and a computational model of a three-dimensional, self-propelled anguilliform swimmer to study the effects of spatial and temporal resolution, domain size, signal-to-noise ratio and out-of-plane effects. Particle image velocimetry measurements of a freely swimming jellyfish medusa and a freely swimming lamprey are analyzed using the method to demonstrate the efficacy of the approach when applied to empirical data. PMID:24115059

Dabiri, John O; Bose, Sanjeeb; Gemmell, Brad J; Colin, Sean P; Costello, John H

2014-02-01

289

Cell-to-cell and long-distance trafficking of the green fluorescent protein in the phloem and symplastic unloading of the protein into sink tissues.  

PubMed Central

Macromolecular trafficking within the sieve element-companion cell complex, phloem unloading, and post-phloem transport were studied using the jellyfish green fluorescent protein (GFP). The GFP gene was expressed in Arabidopsis and tobacco under the control of the AtSUC2 promoter. In wild-type Arabidopsis plants, this promoter regulates expression of the companion cell-specific AtSUC2 sucrose-H+ symporter gene. Analyses of the AtSUC2 promoter-GFP plants demonstrated that the 27-kD GFP protein can traffic through plasmodesmata from companion cells into sieve elements and migrate within the phloem. With the stream of assimilates, the GFP is partitioned between different sinks, such as petals, root tips, anthers, funiculi, or young rosette leaves. Eventually, the GFP can be unloaded symplastically from the phloem into sink tissues, such as the seed coat, the anther connective tissue, cells of the root tip, and sink leaf mesophyll cells. In all of these tissues, the GFP can traffic cell to cell by symplastic post-phloem transport. The presented data show that plasmodesmata of the sieve element-companion cell complex, as well as plasmodesmata into and within the analyzed sinks, allow trafficking of the 27-kD nonphloem GFP protein. The data also show that the size exclusion limit of plasmodesmata can change during organ development. The results are also discussed in terms of the phloem mobility of assimilates and of small, low molecular weight companion cell proteins. PMID:10072393

Imlau, A; Truernit, E; Sauer, N

1999-01-01

290

Pelagia noctiluca (Scyphozoa) crude venom injection elicits oxidative stress and inflammatory response in rats.  

PubMed

Cnidarian toxins represent a rich source of biologically active compounds. Since they may act via oxidative stress events, the aim of the present study was to verify whether crude venom, extracted from the jellyfish Pelagia noctiluca, elicits inflammation and oxidative stress processes, known to be mediated by Reactive Oxygen Species (ROS) production, in rats. In a first set of experiments, the animals were injected with crude venom (at three different doses 6, 30 and 60 µg/kg, suspended in saline solution, i.v.) to test the mortality and possible blood pressure changes. In a second set of experiments, to confirm that Pelagia noctiluca crude venom enhances ROS formation and may contribute to the pathophysiology of inflammation, crude venom-injected animals (30 µg/kg) were also treated with tempol, a powerful antioxidant (100 mg/kg i.p., 30 and 60 min after crude venom). Administration of tempol after crude venom challenge, caused a significant reduction of each parameter related to inflammation. The potential effect of Pelagia noctiluca crude venom in the systemic inflammation process has been here demonstrated, adding novel information about its biological activity. PMID:24727391

Bruschetta, Giuseppe; Impellizzeri, Daniela; Morabito, Rossana; Marino, Angela; Ahmad, Akbar; Spanò, Nunziacarla; Spada, Giuseppa La; Cuzzocrea, Salvatore; Esposito, Emanuela

2014-04-01

291

Pink spot, white spot: the pineal skylight of the leatherback turtle (Dermochelys coriacea Vandelli 1761) skull and its possible role in the phenology of feeding migrations  

USGS Publications Warehouse

Leatherback turtles, Dermochelys coriacea, which have an irregular pink area on the crown of the head known as the pineal or ‘pink spot’, forage upon jellyfish in cool temperate waters along the western and eastern margins of the North Atlantic during the summer. Our study showed that the skeletal structures underlying the pink spot in juvenile and adult turtles are compatible with the idea of a pineal dosimeter function that would support recognition of environmental light stimuli. We interrogated an extensive turtle sightings database to elucidate the phenology of leatherback foraging during summer months around Great Britain and Ireland and compared the sightings with historical data for sea surface temperatures and day lengths to assess whether sea surface temperature or light periodicity/levels were likely abiotic triggers prompting foraging turtles to turn south and leave their feeding grounds at the end of the summer. We found that sea temperature was too variable and slow changing in the study area to be useful as a trigger and suggest that shortening of day lengths as the late summer equilux is approached provides a credible phenological cue, acting via the pineal, for leatherbacks to leave their foraging areas whether they are feeding close to Nova Scotia or Great Britain and Ireland.

Davenport, John; Jones, T. Todd; Work, Thierry M.; Balazs, George H.

2014-01-01

292

Envisioning invertebrates and other aquatic encounters  

NASA Astrophysics Data System (ADS)

To "envision" animals is to visualize, to experience, to figure, to image, kinds of species, discourses, representations, institutions, histories, epistemologies; and, to "imagine possible" a set of material and ethical relationships between species. This dissertation explores the "envisioning of animals" that takes place through/across/between the interfaces of seawater/visuality/experience/biology/technology/phyla---as illustrated in the documentary works of Jean Painleve (scientist and filmmaker), Genevieve Hamon (filmmaker and set-designer), Leni Riefenstahl (filmmaker and photographer), and David Powell (scientist and aquarist). In each case, aesthetic conceptions of beauty and/or ambiguity coupled with biological epistemology and phenomenology of the organisms themselves compete over "what gets to count as culture and nature," and in doing so, construct a host of hybridized and enmeshed "encounters." In the process the following questions are raised: What is the role of the ocean---it's ecosystems and semiotics---in the production of "envisioning"? How are animals used---and in turn shape and reshape the users---to construct tropes of encounter? What theories can be used to understand the phenomenological, semiotic, material, and rhetorical use/miss-use of animals in the articulation of history, economy, biology, narrativity, and representation? How does this motley crew of documentarians answer differently "the animal question," and challenge and/or reinforce anthropocentrism? Divided into two parts, the dissertation first develops a set of methodological questions derived from critical appraisal of "envisioning," encountering, and embodying through science studies, as well as an account of the use and misuse of animals as only "stand ins" for human intentionality; secondly, the dissertation analyses the work of the documentarians in question. Jean Painleve and Genevieve Hamon are shown to critique traditions of representation in nature/science films, particularly through challenging anthropocentrism with a "toolkit" of surrealist strategies and a biological knowledge of octopuses. Soft and hard corals (anthrozoans) are shown to enact a "biosemiotics" or "zoosemiotics" that "presses against" Leni Riefenstahl's "fascist (and humanist) aesthetic," which desires to memorialize "beautiful and unpolluted" coral communities. "The Drifter's Gallery," the primary designer being David Powell, at the Monterey Bay Aquarium, is shown to install a promise of immediate and luminous experience of "jellyfish otherness," but delivers an account of jellyfish as historically situated "actors" with in biocapitalism. The work of these documentarians is particularly prescient, considering the growing international concern about coral bleaching, anthropogenic pollution, over-harvesting, and commercialization of the oceans' resources. As a form of "situated knowledge," this dissertation expands the boundaries of "who/what gets to count?" to encompass an ethical concern about systems of power that constitutively produce animal and human actors. If we are to be committed to understanding the encounters and formations of encounters between non-human animals and human animals, then projects that bridge---rather than divide---disciplines are necessary endeavors for more inhabitable futures; this project attempts such a bridge.

Hayward, Eva

293

Cyclic AMP Receptor Protein-Aequorin Molecular Switch for Cyclic AMP  

PubMed Central

Molecular switches are designer molecules that combine the functionality of two individual proteins into one, capable of manifesting an “on/off” signal in response to a stimulus. These switches have unique properties and functionalities and thus, can be employed as nanosensors in a variety of applications. To that end, we have developed a bioluminescent molecular switch for cyclic AMP. Bioluminescence offers many advantages over fluorescence and other detection methods including the fact that there is essentially zero background signal in physiological fluids, allowing for more sensitive detection and monitoring. The switch was created by combining the properties of the cyclic AMP receptor protein (CRP), a transcriptional regulatory protein from E. coli that binds selectively to cAMP with those of aequorin, a bioluminescent photoprotein native of the jellyfish Aequorea victoria. Genetic manipulation to split the genetic coding sequence of aequorin in two and genetically attach the fragments to the N and C termini of CRP, resulted in a hybrid protein molecular switch. The conformational change experienced by CRP upon the binding of cyclic AMP is suspected to result in the observed loss of bioluminescent signal from aequorin. The “on/off” bioluminescence can be modulated by cyclic AMP over a range of several orders of magnitude in a linear fashion in addition to the capacity to detect changes in cellular cyclic AMP of intact cells exposed to different external stimuli without the need to lyse the cells. We envision that the molecular switch could find applications in vitro as well as in vivo cyclic AMP detection and/or imaging. PMID:21329338

Scott, Daniel; Hamorsky, Krystal Teasley; Ensor, C. Mark; Anderson, Kimberly W.; Daunert, Sylvia

2011-01-01

294

Burst Feeding of Pelagia noctiluca ephyrae on Atlantic Bluefin Tuna (Thunnus thynnus) Eggs  

PubMed Central

This study investigates the predation of P. noctiluca ephyrae on Atlantic Bluefin tuna (ABFT) eggs under different experimental conditions. The specific factors considered in the experimental design were: a) water mix conditions to explore predation under two-dimensional (2D) and three-dimensional (3D) prey distributions, b) prey density to investigate the ingestion rate capacity, and c) incubation time to inspect gut saturation. The eggs and jellyfish ephyrae were collected during the 2012 ABFT spawning survey off Ibiza (Balearic Isl., Western Mediterranean). The results showed that the proportion of feeding ephyrae increased with size. The mean clearance rate of feeding ephyrae, 4.14 L h-1, was the highest ever recorded for ephyrae. Under calm conditions the eggs floated at the surface (2D spatial arrangement) and the clearance rates, at low prey densities, were at least twice those under mixed conditions (3D spatial arrangement). At high prey density, clearance rate did not differ between mix conditions, probably due to the fast gut saturation, which was reached in c.a. 15 min, as revealed by time series observations of gut contents. The fast saturation of ephyrae and their slow digestion time of approximately 18 h suggest the existence of a diel feeding periodicity. We conclude that in the Western Mediterranean, P. noctiluca ephyrae are capable of predating on ABFT eggs, a highly pulsed and spatially restricted resource that potentially switches from a 3D to a 2D configuration in the absence of wind-generated turbulence. The P. noctiluca and Atlantic Bluefin tuna egg system might represent an example of a general mechanism linking pelagic and neustonic food webs. PMID:24069335

Gordoa, Ana; Acuna, Jose Luis; Farres, Roser; Bacher, Kathrin

2013-01-01

295

These are not the k-mers you are looking for: efficient online k-mer counting using a probabilistic data structure.  

PubMed

K-mer abundance analysis is widely used for many purposes in nucleotide sequence analysis, including data preprocessing for de novo assembly, repeat detection, and sequencing coverage estimation. We present the khmer software package for fast and memory efficient online counting of k-mers in sequencing data sets. Unlike previous methods based on data structures such as hash tables, suffix arrays, and trie structures, khmer relies entirely on a simple probabilistic data structure, a Count-Min Sketch. The Count-Min Sketch permits online updating and retrieval of k-mer counts in memory which is necessary to support online k-mer analysis algorithms. On sparse data sets this data structure is considerably more memory efficient than any exact data structure. In exchange, the use of a Count-Min Sketch introduces a systematic overcount for k-mers; moreover, only the counts, and not the k-mers, are stored. Here we analyze the speed, the memory usage, and the miscount rate of khmer for generating k-mer frequency distributions and retrieving k-mer counts for individual k-mers. We also compare the performance of khmer to several other k-mer counting packages, including Tallymer, Jellyfish, BFCounter, DSK, KMC, Turtle and KAnalyze. Finally, we examine the effectiveness of profiling sequencing error, k-mer abundance trimming, and digital normalization of reads in the context of high khmer false positive rates. khmer is implemented in C++ wrapped in a Python interface, offers a tested and robust API, and is freely available under the BSD license at github.com/ged-lab/khmer. PMID:25062443

Zhang, Qingpeng; Pell, Jason; Canino-Koning, Rosangela; Howe, Adina Chuang; Brown, C Titus

2014-01-01

296

Imaging long distance propagating calcium signals in intact plant leaves with the BRET-based GFP-aequorin reporter  

PubMed Central

Calcium (Ca2+) is a second messenger involved in many plant signaling processes. Biotic and abiotic stimuli induce Ca2+ signals within plant cells, which, when decoded, enable these cells to adapt in response to environmental stresses. Multiple examples of Ca2+ signals from plants containing the fluorescent yellow cameleon sensor (YC) have contributed to the definition of the Ca2+ signature in some cell types such as root hairs, pollen tubes and guard cells. YC is, however, of limited use in highly autofluorescent plant tissues, in particular mesophyll cells. Alternatively, the bioluminescent reporter aequorin enables Ca2+ imaging in the whole plant, including mesophyll cells, but this requires specific devices capable of detecting the low amounts of emitted light. Another type of Ca2+ sensor, referred to as GFP-aequorin (G5A), has been engineered as a chimeric protein, which combines the two photoactive proteins from the jellyfish Aequorea victoria, the green fluorescent protein (GFP) and the bioluminescent protein aequorin. The Ca2+-dependent light-emitting property of G5A is based on a bioluminescence resonance energy transfer (BRET) between aequorin and GFP. G5A has been used for over 10 years for enhanced in vivo detection of Ca2+ signals in animal tissues. Here, we apply G5A in Arabidopsis and show that G5A greatly improves the imaging of Ca2+ dynamics in intact plants. We describe a simple method to image Ca2+ signals in autofluorescent leaves of plants with a cooled charge-coupled device (cooled CCD) camera. We present data demonstrating how plants expressing the G5A probe can be powerful tools for imaging of Ca2+ signals. It is shown that Ca2+ signals propagating over long distances can be visualized in intact plant leaves and are visible mainly in the veins. PMID:24600459

Xiong, Tou Cheu; Ronzier, Elsa; Sanchez, Frederic; Corratge-Faillie, Claire; Mazars, Christian; Thibaud, Jean-Baptiste

2014-01-01

297

Cnidarian phylogenetic relationships as revealed by mitogenomics  

PubMed Central

Background Cnidaria (corals, sea anemones, hydroids, jellyfish) is a phylum of relatively simple aquatic animals characterized by the presence of the cnidocyst: a cell containing a giant capsular organelle with an eversible tubule (cnida). Species within Cnidaria have life cycles that involve one or both of the two distinct body forms, a typically benthic polyp, which may or may not be colonial, and a typically pelagic mostly solitary medusa. The currently accepted taxonomic scheme subdivides Cnidaria into two main assemblages: Anthozoa (Hexacorallia?+?Octocorallia) – cnidarians with a reproductive polyp and the absence of a medusa stage – and Medusozoa (Cubozoa, Hydrozoa, Scyphozoa, Staurozoa) – cnidarians that usually possess a reproductive medusa stage. Hypothesized relationships among these taxa greatly impact interpretations of cnidarian character evolution. Results We expanded the sampling of cnidarian mitochondrial genomes, particularly from Medusozoa, to reevaluate phylogenetic relationships within Cnidaria. Our phylogenetic analyses based on a mitochogenomic dataset support many prior hypotheses, including monophyly of Hexacorallia, Octocorallia, Medusozoa, Cubozoa, Staurozoa, Hydrozoa, Carybdeida, Chirodropida, and Hydroidolina, but reject the monophyly of Anthozoa, indicating that the Octocorallia?+?Medusozoa relationship is not the result of sampling bias, as proposed earlier. Further, our analyses contradict Scyphozoa [Discomedusae?+?Coronatae], Acraspeda [Cubozoa?+?Scyphozoa], as well as the hypothesis that Staurozoa is the sister group to all the other medusozoans. Conclusions Cnidarian mitochondrial genomic data contain phylogenetic signal informative for understanding the evolutionary history of this phylum. Mitogenome-based phylogenies, which reject the monophyly of Anthozoa, provide further evidence for the polyp-first hypothesis. By rejecting the traditional Acraspeda and Scyphozoa hypotheses, these analyses suggest that the shared morphological characters in these groups are plesiomorphies, originated in the branch leading to Medusozoa. The expansion of mitogenomic data along with improvements in phylogenetic inference methods and use of additional nuclear markers will further enhance our understanding of the phylogenetic relationships and character evolution within Cnidaria. PMID:23302374

2013-01-01

298

Energy, ageing, fidelity and sex: oocyte mitochondrial DNA as a protected genetic template.  

PubMed

Oxidative phosphorylation couples ATP synthesis to respiratory electron transport. In eukaryotes, this coupling occurs in mitochondria, which carry DNA. Respiratory electron transport in the presence of molecular oxygen generates free radicals, reactive oxygen species (ROS), which are mutagenic. In animals, mutational damage to mitochondrial DNA therefore accumulates within the lifespan of the individual. Fertilization generally requires motility of one gamete, and motility requires ATP. It has been proposed that oxidative phosphorylation is nevertheless absent in the special case of quiescent, template mitochondria, that these remain sequestered in oocytes and female germ lines and that oocyte mitochondrial DNA is thus protected from damage, but evidence to support that view has hitherto been lacking. Here we show that female gametes of Aurelia aurita, the common jellyfish, do not transcribe mitochondrial DNA, lack electron transport, and produce no free radicals. In contrast, male gametes actively transcribe mitochondrial genes for respiratory chain components and produce ROS. Electron microscopy shows that this functional division of labour between sperm and egg is accompanied by contrasting mitochondrial morphology. We suggest that mitochondrial anisogamy underlies division of any animal species into two sexes with complementary roles in sexual reproduction. We predict that quiescent oocyte mitochondria contain DNA as an unexpressed template that avoids mutational accumulation by being transmitted through the female germ line. The active descendants of oocyte mitochondria perform oxidative phosphorylation in somatic cells and in male gametes of each new generation, and the mutations that they accumulated are not inherited. We propose that the avoidance of ROS-dependent mutation is the evolutionary pressure underlying maternal mitochondrial inheritance and the developmental origin of the female germ line. PMID:23754815

de Paula, Wilson B M; Lucas, Cathy H; Agip, Ahmed-Noor A; Vizcay-Barrena, Gema; Allen, John F

2013-07-19

299

The x-ray structure of dTDP-4-keto-6-deoxy-D-glucose-3,4-ketoisomerase.  

PubMed

The repeating unit of the glycan chain in the S-layer of the bacterium Aneurinibacillus thermoaerophilus L420-91(T) is composed of four alpha-d-rhamnose molecules and two 3-acetamido-3,6-dideoxy-alpha-d-galactose moieties (abbreviated as Fucp3NAc). Formation of the glycan layer requires nucleotide-activated sugars as the donor molecules. Whereas the enzymes involved in the synthesis of GDP-rhamnose have been well characterized, less is known regarding the structures and enzymatic mechanisms of the enzymes required for the production of dTDP-Fucp3NAc. One of the enzymes involved in the biosynthesis of dTDP-Fucp3NAc is a 3,4-ketoisomerase, hereafter referred to as FdtA. Here we describe the first three-dimensional structure of this sugar isomerase complexed with dTDP and solved to 1.5 A resolution. The FdtA dimer assumes an almost jellyfish-like appearance with the sole alpha-helices representing the tentacles. Formation of the FdtA dimer represents a classical example of domain swapping whereby beta-strands 2 and 3 from one subunit form part of a beta-sheet in the second subunit. The active site architecture of FdtA is characterized by a cluster of three histidine residues, two of which, His(49) and His(51), appear to be strictly conserved in the amino acid sequences deposited to date. Site-directed mutagenesis experiments, enzymatic assays, and x-ray crystallographic analyses suggest that His(49) functions as an active site base. PMID:17459872

Davis, Melissa L; Thoden, James B; Holden, Hazel M

2007-06-29

300

Imprudent fishing harvests and consequent trophic cascades on the West Florida shelf over the last half century: A harbinger of increased human deaths from paralytic shellfish poisoning along the southeastern United States, in response to oligotrophication?  

NASA Astrophysics Data System (ADS)

Within the context of ubiquitous overfishing of piscivores, recent consequent increments of jellyfish and clupeids have occurred at the zooplanktivore trophic level in the eastern Gulf of Mexico (GOM), after overfishing of one of their predators, i.e. red snapper. Initiation of a local trophic cascade thence led to declines of herbivore stocks, documented here on the West Florida shelf. These exacerbating world-wide trophic cascades have resulted in larger harmful algal blooms (HABs), already present at the base of most coastal food webs. Impacts on human health have thus far been minimal within nutrient-rich coastal regions. To provide a setting for past morbidities, consideration is given to chronologies of other trophic cascades within eutrophic, cold water marine ecosystems of the Scotian Sea, in the Gulf of Alaska, off Southwest Africa, within the Barents, White, and Black Seas, in the Gulf of Maine, and finally in the North Sea. Next, comparison is now made here of recent ten-fold increments within Florida waters of both relatively benign and saxitoxic HABs, some of which are fatal to humans. These events are placed in a perspective of other warm shelf systems of the South China and Caribbean Seas to assess prior and possible future poison toxicities of oligotrophic coastal habitats. Past wide-spread kills of fishes and sea urchins over the Caribbean Sea and the downstream GOM are examined in relation to the potential transmission of dinoflagellate saxitoxin and other epizootic poison vectors by western boundary currents over larger "commons" than local embayments. Furthermore, since some HABs produce more potent saxitoxins upon nutrient depletion, recent decisions to ban seasonal fertilizer applications to Florida lawns may have unintended consequences. In the future, human-killing phytoplankton, rather than relatively benign fish-killing HABs of the past, may be dispersed along the southeastern United States seaboard.

Walsh, J. J.; Tomas, C. R.; Steidinger, K. A.; Lenes, J. M.; Chen, F. R.; Weisberg, R. H.; Zheng, L.; Landsberg, J. H.; Vargo, G. A.; Heil, C. A.

2011-06-01

301

Molecular evidence for deep evolutionary roots of bilaterality in animal development  

PubMed Central

Nearly all metazoans show signs of bilaterality, yet it is believed the bilaterians arose from radially symmetric forms hundreds of millions of years ago. Cnidarians (corals, sea anemones, and “jellyfish”) diverged from other animals before the radiation of the Bilateria. They are diploblastic and are often characterized as being radially symmetrical around their longitudinal (oral–aboral) axis. We have studied the deployment of orthologs of a number of family members of developmental regulatory genes that are expressed asymmetrically during bilaterian embryogenesis from the sea anemone, Nematostella vectensis. The secreted TGF-? genes Nv-dpp, Nv-BMP5–8, six TGF-? antagonists (NvChordin, NvNoggin1, NvNoggin2, NvGremlin, NvFollistatin, and NvFollistatin-like), the homeodomain proteins NvGoosecoid (NvGsc) and NvGbx, and the secreted guidance factor, NvNetrin, were studied. NvDpp, NvChordin, NvNoggin1, NvGsc, and NvNetrin are expressed asymmetrically along the axis perpendicular to the oral–aboral axis, the directive axis. Furthermore, NvGbx, and NvChordin are expressed in restricted domains on the left and right sides of the body, suggesting that the directive axis is homologous with the bilaterian dorsal–ventral axis. The asymmetric expression of NvNoggin1 and NvGsc appear to be maintained by the canonical Wnt signaling pathway. The asymmetric expression of NvNoggin1, NvNetrin, and Hox orthologs NvAnthox7, NvAnthox8, NvAnthox1a, and NvAnthox6, in conjunction with the observation that NvNoggin1 is able to induce a secondary axis in Xenopus embryos argues that N. vectensis could possess antecedents of the organization of the bilaterian central nervous system. PMID:16837574

Matus, David Q.; Pang, Kevin; Marlow, Heather; Dunn, Casey W.; Thomsen, Gerald H.; Martindale, Mark Q.

2006-01-01

302

Generation of human lactoferrin transgenic cloned goats using donor cells with dual markers and a modified selection procedure.  

PubMed

The objective was to use dual markers to accurately select genetically modified donor cells and ensure that the resulting somatic cell nuclear transfer kids born were transgenic. Fetal fibroblast cells were transfected with dual marking gene vector (pCNLF-ng) that contained the red-shifted variant of the jellyfish green fluorescent protein (LGFP) and neomycin resistance (Neo) markers. Cell clones that were G418-resistant and polymerase chain reaction-positive were subcultured for several passages; individual cells of the clones were examined with fluorescence microscopy to confirm transgenic integration. Clones in which every cell had bright green fluorescence were used as donor cells for nuclear transfer. In total, 86.7% (26/30) cell clones were confirmed to have transgenic integration of the markers by polymerase chain reaction, 76.7% (23/30) exhibited fluorescence, but only 40% (12/30) of these fluorescent cell clones had fluorescence in all cell populations. Moreover, through several cell passages, only 20% (6/30) of the cell clones exhibited stable LGFP expression. Seven transgenic cloned offspring were produced from these cells by nuclear transfer. Overall, the reconstructed embryo fusion rate was 76.6%, pregnancy rates at 35 and 60 days were 39.1% and 21.7%, respectively, and the offspring birth rate was 1.4%. There were no significant differences between nuclear transfer with dual versus a single (Neo) marker (overall, 73.8% embryo fusion rate, 53.8% and 26.9% pregnancy rates, and 1.9% birth rate with five offspring). In conclusion, the use of LGFP/Neo dual markers and an optimized selection procedure reliably screened genetically modified donor cells, excluded pseudotransgenic cells, and led to production of human lactoferrin transgenic goats. Furthermore, the LGFP/Neo markers had no adverse effects on the efficiency of somatic cell nuclear transfer. PMID:22898014

An, Li-You; Yuan, Yu-Guo; Yu, Bao-Li; Yang, Ting-Jia; Cheng, Yong

2012-10-01

303

Minimum clinically significant VAS differences for simultaneous (paired) interval serial pain assessments.  

PubMed

We conducted two studies to determine whether the minimum clinically significant difference in the visual analog scale (VAS) for nearly simultaneous and brief-interval serial assessments of pain is less than that for pain assessment at 20- to 30-minute intervals, using a 10-cm VAS. The first study was a blinded, randomized, placebo-controlled paired trial comparing the pain of intravenous cannulation in both hands (20-minute application of a eutectic mixture of local anesthetics v placebo) of study subjects. The second study was a non-blinded, randomized, paired trial of different treatments for jellyfish stings. In the first study, 37 of 40 subjects indicated that one hand experienced more pain than the other. Eleven of these 37 subjects (30%) indicated differences in VAS values of 1.0 cm or less, with a minimum value of 0.5 cm. In the second study, for all the VAS-based pain comparisons, VAS differences of

Yamamoto, Loren G; Nomura, Jason T; Sato, Renee L; Ahern, Reina M; Snow, Joanne L; Kuwaye, Todd T

2003-05-01

304

Spatio-temporal foraging patterns of a giant zooplanktivore, the leatherback turtle  

NASA Astrophysics Data System (ADS)

Understanding food web functioning through the study of natural bio-indicators may constitute a valuable and original approach. In the context of jellyfish proliferation in many overexploited marine ecosystems studying the spatio-temporal foraging patterns of the giant "jellyvore" leatherback turtle turns out to be particularly relevant. Here we analyzed long-term tracking data to assess spatio-temporal foraging patterns in 21 leatherback turtles during their pluri-annual migration in the Northern Atlantic. Through an analytical approach based on the animal's own motion (independent of currents) and diving behavior distinct zones of high and low foraging success were identified. High foraging success occurred in a sub-equatorial zone spanning the width of the Atlantic and at high (>30°N) latitudes. Between these zones in the centre of North Atlantic gyre there was low foraging success. This "ocean desert" area was traversed at high speed by leatherbacks on their way to more productive areas at higher latitudes. Animals traveled slowly in high foraging success areas and dived shallower (17.2 ± 8.0 km day - 1 and 53.6 ± 33.1 m mean ± SD respectively) than in low foraging success areas (51.0 ± 13.1 km day - 1 and 81.8 ± 56.2 m mean ± SD respectively). These spatio-temporal foraging patterns seem to relatively closely match the main features of the integrated meso-zooplankton distribution in the North Atlantic. Our method of defining high foraging success areas is intuitive and relatively easy to implement but also takes into account the impact of oceanic currents on animal's behavior.

Fossette, Sabrina; Hobson, Victoria J.; Girard, Charlotte; Calmettes, Beatriz; Gaspar, Philippe; Georges, Jean-Yves; Hays, Graeme C.

2010-05-01

305

A novel method for monitoring Mycobacterium bovis BCG trafficking with recombinant BCG expressing green fluorescent protein.  

PubMed Central

To better understand intracellular and extracellular trafficking of Mycobacterium bovis bacillus Calmette-Guérin (BCG) when used as an intravesical agent in the treatment of transitional cell carcinoma (TCC) of the bladder, recombinant BCG (rBCG) expressing the jellyfish green fluorescent protein (GFP) was created. When the MB49.1 murine TCC cell line was incubated with GFP-expressing rBCG, internalization of the pathogen could be directly visualized by UV microscopy and quantitated by flow cytometry. The in vitro internalization of the GFP rBCG by the bladder tumor cells was temperature dependent, occurring most readily at 37 degrees C and being severely inhibited at 4 degrees C. Optimum internalization was achieved in vitro at a 10:1 BCG-to-tumor cell ratio over 24 h during which approximately 16% of the tumor cells became infected. Cytochalasin B, a phagocytosis inhibitor, abrogated the ingestion by almost 100% at a concentration of 200 micrograms/ml, indicating that contractile microfilaments likely played an important role in this process. By using mitomycin, a DNA cross-linking reagent, to inhibit proliferation of MB49.1 cells, clearance of about 40% of the green rBCG was achieved by 3 days postinfection. No significant difference between the GFP rBCG and wild-type BCG was observed in the ability to induce the expression of cell membrane proteins of major histocompatibility classes I and II, ICAM-I and -II, B7-1 and -2, of Fas from MB49.1 cells or cytokine production from mouse spleen cells. These results indicate that GFP rBCG may serve as a useful substitute for wild-type BCG in future studies of in vivo trafficking experimental and clinical immunotherapy. PMID:8914772

Luo, Y; Szilvasi, A; Chen, X; DeWolf, W C; O'Donnell, M A

1996-01-01

306

Expression of GFP in tumor cells and fluorescent examination by confocal microscope  

NASA Astrophysics Data System (ADS)

The green fluorescent protein (GFP), from the bioluminescent jellyfish Aequorea victoria, yields a bright green fluorescence when expressed in either eukaryotic or prokaryotic cells and illuminated by blue or UV light. The characteristic properties of GFP make this protein a good candidate for use as a molecular reporter to monitor patterns of protein localization, gene expression, and intracellular protein trafficking in living cells. In this study, the plasmid EGFP encoding GFP was used to transfect SWO cells (a cancer cell line of nerve gelatinous tissue) mediated by liposome: (1) The plasmid EGFP-C1, purchased from Clontech Co., propagated in suitable E. coli strain (JM 109), was extracted by Concert High Purity Plasmid Miniprep (Gibco). (2) SWO was cultured in RPMI 1640 (10% FCS and 25 mM HEPES), 37 degree(s)C, 5% CO2. Cancer cells were transfected in 6-cm tissue culture dishes by Lipofectin Reagent (Gibco) for 6-12 hr using 2 ug DNA. (3) Then, infected cells were collected in medium containing 800 ug/ml G418, and the resistant clones were harvested and subcloned in fresh culture medium maintaining 800 ug/ml G418. (4) The cells were examined by using Nikon fluorescent microscope (E600) and Bio-Rad confocal microscope (MRC 600). (5) Next step, the cancer cells, stably expressing GFP after in vivo transduction, were implanted by surgical orthotopic implantation (SOI) in nude mice. Tracking of these cancer cells will become more sensitive and rapid than the traditional procedure of histopathological examination or immunohistochemistry. This method demonstrates external, noninvasive, whole-body, real-time fluorescence optical imaging of internally growing tumors and metastases in transplanted animals.

Jin, Ying; Xing, Da; Xu, Chaoyang

2002-04-01

307

Dual color microscopic imagery of cells expressing the green fluorescent protein and a red-shifted variant.  

PubMed

The green fluorescent protein (GFP) from the jellyfish, Aequorea victoria, has become a versatile reporter for monitoring gene expression and protein localization in a variety of cells and organisms. GFP emits bright green light (lambda max = 510 nm) when excited with ultraviolet (UV) or blue light (lambda max = 395 nm, minor peak at 470 nm). The chromophore in GFP is intrinsic to the primary structure of the protein, and fluorescence from GFP does not require additional gene products, substrates or other factors. GFP fluorescence is stable, species-independent and can be monitored noninvasively using the techniques of fluorescence microscopy and flow cytometry [Chalfie et al., Science 263 (1994) 802-805; Stearns, Curr. Biol. 5 (1995) 262-264]. The protein appears to undergo an autocatalytic reaction to create the fluorophore [Heim et al., Proc. Natl. Acad. Sci. USA 91 (1994) 12501-12504] in a process involving cyclization of a Tyr66 aa residue. Recently [Delagrave et al., Bio/Technology 13 (1995) 151-154], a combinatorial mutagenic strategy was targeted at aa 64 through 69, which spans the chromophore of A. victoria GFP, yielding a number of different mutants with red-shifted fluorescence excitation spectra. One of these, RSGFP4, retains the characteristic green emission spectra (lambda max = 505 nm), but has a single excitation peak (lambda max = 490 nm). The fluorescence properties of RSGFP4 are similar to those of another naturally occurring GFP from the sea pansy, Renilla reniformis [Ward and Cormier, Photobiochem. Photobiol. 27 (1978) 389-396]. In the present study, we demonstrate by fluorescence microscopy that selective excitation of A. victoria GFP and RSGFP4 allows for spectral separation of each fluorescent signal, and provides the means to image these signals independently in a mixed population of bacteria or mammalian cells. PMID:8707051

Yang, T T; Kain, S R; Kitts, P; Kondepudi, A; Yang, M M; Youvan, D C

1996-01-01

308

Assessing Fishing and Marine Biodiversity Changes Using Fishers' Perceptions: The Spanish Mediterranean and Gulf of Cadiz Case Study  

PubMed Central

Background The expansion of fishing activities has intensively transformed marine ecosystems worldwide. However, available time series do not frequently cover historical periods. Methodology Fishers' perceptions were used to complement data and characterise changes in fishing activity and exploited ecosystems in the Spanish Mediterranean Sea and Gulf of Cadiz. Fishers' interviews were conducted in 27 fishing harbours of the area, and included 64 fishers from ages between 20 to >70 years old to capture the experiences and memories of various generations. Results are discussed in comparison with available independent information using stock assessments and international convention lists. Principal Findings According to fishers, fishing activity substantially evolved in the area with time, expanding towards deeper grounds and towards areas more distant from the coast. The maximum amount of catch ever caught and the weight of the largest species ever captured inversely declined with time. Fishers (70%) cited specific fishing grounds where depletion occurred. They documented ecological changes of marine biodiversity during the last half of the century: 94% reported the decline of commercially important fish and invertebrates and 61% listed species that could have been extirpated, with frequent mentions to cartilaginous fish. Declines and extirpations were in line with available quantitative evaluations from stock assessments and international conventions, and were likely linked to fishing impacts. Conversely, half of interviewed fishers claimed that several species had proliferated, such as cephalopods, jellyfish, and small-sized fish. These changes were likely related to trophic cascades due to fishing and due to climate change effects. The species composition of depletions, local extinctions and proliferations showed differences by region suggesting that regional dynamics are important when analysing biodiversity changes. Conclusions/Significance Using fishers' perceptions, fishing and ecological changes in the study area were documented. The recovery of local ecological knowledge provides valuable information complementing quantitative monitoring and evaluation surveys. PMID:24465644

Coll, Marta; Carreras, Marta; Ciercoles, Cristina; Cornax, Maria-Jose; Gorelli, Giulia; Morote, Elvira; Saez, Raquel

2014-01-01

309

Directed evolution of a monomeric, bright and photostable version of Clavularia cyan fluorescent protein: structural characterization and applications in fluorescence imaging.  

PubMed

The arsenal of engineered variants of the GFP [green FP (fluorescent protein)] from Aequorea jellyfish provides researchers with a powerful set of tools for use in biochemical and cell biology research. The recent discovery of diverse FPs in Anthozoa coral species has provided protein engineers with an abundance of alternative progenitor FPs from which improved variants that complement or supersede existing Aequorea GFP variants could be derived. Here, we report the engineering of the first monomeric version of the tetrameric CFP (cyan FP) cFP484 from Clavularia coral. Starting from a designed synthetic gene library with mammalian codon preferences, we identified dimeric cFP484 variants with fluorescent brightness significantly greater than the wild-type protein. Following incorporation of dimer-breaking mutations and extensive directed evolution with selection for blue-shifted emission, high fluorescent brightness and photostability, we arrived at an optimized variant that we have named mTFP1 [monomeric TFP1 (teal FP 1)]. The new mTFP1 is one of the brightest and most photostable FPs reported to date. In addition, the fluorescence is insensitive to physiologically relevant pH changes and the fluorescence lifetime decay is best fitted as a single exponential. The 1.19 A crystal structure (1 A=0.1 nm) of mTFP1 confirms the monomeric structure and reveals an unusually distorted chromophore conformation. As we experimentally demonstrate, the high quantum yield of mTFP1 (0.85) makes it particularly suitable as a replacement for ECFP (enhanced CFP) or Cerulean as a FRET (fluorescence resonance energy transfer) donor to either a yellow or orange FP acceptor. PMID:16859491

Ai, Hui-wang; Henderson, J Nathan; Remington, S James; Campbell, Robert E

2006-12-15

310

Energy, ageing, fidelity and sex: oocyte mitochondrial DNA as a protected genetic template  

PubMed Central

Oxidative phosphorylation couples ATP synthesis to respiratory electron transport. In eukaryotes, this coupling occurs in mitochondria, which carry DNA. Respiratory electron transport in the presence of molecular oxygen generates free radicals, reactive oxygen species (ROS), which are mutagenic. In animals, mutational damage to mitochondrial DNA therefore accumulates within the lifespan of the individual. Fertilization generally requires motility of one gamete, and motility requires ATP. It has been proposed that oxidative phosphorylation is nevertheless absent in the special case of quiescent, template mitochondria, that these remain sequestered in oocytes and female germ lines and that oocyte mitochondrial DNA is thus protected from damage, but evidence to support that view has hitherto been lacking. Here we show that female gametes of Aurelia aurita, the common jellyfish, do not transcribe mitochondrial DNA, lack electron transport, and produce no free radicals. In contrast, male gametes actively transcribe mitochondrial genes for respiratory chain components and produce ROS. Electron microscopy shows that this functional division of labour between sperm and egg is accompanied by contrasting mitochondrial morphology. We suggest that mitochondrial anisogamy underlies division of any animal species into two sexes with complementary roles in sexual reproduction. We predict that quiescent oocyte mitochondria contain DNA as an unexpressed template that avoids mutational accumulation by being transmitted through the female germ line. The active descendants of oocyte mitochondria perform oxidative phosphorylation in somatic cells and in male gametes of each new generation, and the mutations that they accumulated are not inherited. We propose that the avoidance of ROS-dependent mutation is the evolutionary pressure underlying maternal mitochondrial inheritance and the developmental origin of the female germ line. PMID:23754815

de Paula, Wilson B. M.; Lucas, Cathy H.; Agip, Ahmed-Noor A.; Vizcay-Barrena, Gema; Allen, John F.

2013-01-01

311

Application of a liposomal bioluminescent label in the development of a flow injection immunoanalytical system.  

PubMed

A flow injection liposome immunoanalytical system was developed using biotin as the model analyte and liposomal aequorin as the label. Aequorin is a photoprotein isolated from luminescent jellyfish (notably Aequorea victoria) and other marine organisms that emits visible light in the presence of a trace of Ca2+. Because of this characteristic, the aequorin complex has been used as an intracellular Ca2+ indicator. In this study, a bioluminescent label was designed by encapsulating aequorin inside the cavity of the liposome, whose outer surface was sensitized with the analyte of interest. The analyte-tagged liposomal aequorin was employed in the development of a heterogeneous bioluminescence immunoassay for the model analyte biotin. The proposed immunoassay was based on the competition between the model biotin and aequorin-encapsulating, biotin-tagged liposomes for a limited number of anti-biotin antibody-binding sites. The anti-biotin antibodies were immobilized via protein A in a capillary immunoreactor column, and 30% MeOH was used for the regeneration of antibody-binding sites after each measurement, which allowed the immunoreactor to be used for up to 50 sequential sample injections without any loss of reactivity. The calibration curve for biotin in Tris-buffered saline solution had a linear range of 1 x 10(-11)-1 x 10(-3) M. The detection limit of the assay was 50 pg (equivalent to 200-microL injection of 1 x 10(-9) M). This study demonstrates the procedures for the encapsulation of the photoprotein aequorin into the liposome, which can be used as a sensitive label in bioluminescence immunoassays for biotin or in other applications. PMID:15924372

Ho, Ja-an Annie; Huang, Ming-Ray

2005-06-01

312

Low Frequency Electromagnetic Background Radiation From Electron Acceleration Above Thunderclouds  

NASA Astrophysics Data System (ADS)

It was recently proposed that the acceleration of electrons during the growth and branching of streamers above thunderclouds initiated by intense lightning discharges could result in detectable low frequency electromagnetic radiation from several tens of kHz up to several hundreds of kHz (Qin et al., GRL, 2012). The intensity of the predicted radiation scales with the streamer density which is particularly large during spectacular sprite occurrences such as jellyfish sprites and/or dancing sprites. Dancing sprites are up to one second long sequences of consecutive sprites or sprite groups which are typically separated by some hundreds of milliseconds and which tend to follow the spatial development of large scale intracloud lightning discharges. A particularly spectacular series of 10 dancing sprite events over a Mediterranean mesoscale convective system was recorded with a low light video camera in south-eastern France during the early morning hours of August 31, 2012. Each dancing sprite event was composed of ~3-4 consecutive sprites or groups of sprites. All of these sprite occurrences were associated with a sudden enhancement ~2 uV/m/Hz-1/2 of the low frequency electromagnetic background radiation as measured with a radio receiver in south-west England. It is estimated that ~1000 streamers at a height of ~40 km are necessary to epxlain the observed electric field strengths. These sudden enhancements are superimposed on a more continuous low frequency electromagnetic background radiation which accompanies each dancing sprite event. It is speculated that this low frequency 'radio glow' results from filamentary streamers near the cloud top as a result of the large scale electrostatic charging of the thundercloud and that it may be used as an indicator for sprite occurrences in future studies.

Fullekrug, Martin; Mezentsev, Andrew; Soula, Serge; van der Velde, Oscar; Farges, Thomas

2013-04-01

313

Neurobiology of Stomotoca. II. Pacemakers and conduction pathways.  

PubMed

Evidence is presented for separate conduction pathways for swimming and for tentacle coordination in the marginal nerves of the jellyfish Stomotoca. The effector muscles are fired through junctions sensitive to excess Mg++, probably represented by the neuromuscular synapses observed by electron microscopy. The swimming effector (striated muscle) fires one-to-one with nerve input signals and myoid conduction occurs. Tentacle responses (smooth muscle contractions) involve facilitation, presumably at the neuro-effector junction; responses are graded and nonpropagating. Electrical correlates of two further conducting systems using the marginal nerves have been recorded. Their functions are unknown. One, the bridge system, extends up the four radii and encircles the peduncle; the other (ring system) is confined to the margin. A fifth conducting system is inferred in the case of the pointing response and its distribution is plotted. Signals have not been obtained from it. Pointing is accompanied by a burst of muscle potentials in the radial smooth muscles and is exhibited after a lengthy latency, indicating a local pacemaker. A sixth conducting pathway is the epithelial system, which mediates crumpling, a response involving the radial muscles without pacemaker intervention. Characteristic conduction velocities and wave forms are noted for the first four systems and for epithelial pulses. All systems, except perhaps the pointing conduction system, through-conduct under excess Mg++. Spontaneous activity patterns are described for the swimming, tentacle pulse, and ring systems. Abrupt increases in light intensity inhibit spontaneous activity, sudden decreases augmenting it. In the absence of specialized photoreceptors, light is presumed to act directly on central neurons. Epithelial pulses inhibit swimming, apparently by blocking the generation or conduction of the primary nervous events. This observation, taken in conjunction with evidence of feedback inhibition of the primary swimming system by the cells it fires, is discussed in relation to possible mechanisms whereby the output of nerve cells might be altered by activity in the excitable epithelial cells which envelop them. PMID:241778

Mackie, G O

1975-07-01

314

Ancient origins of axial patterning genes: Hox genes and ParaHox genes in the Cnidaria.  

PubMed

Among the bilaterally symmetrical, triploblastic animals (the Bilateria), a conserved set of developmental regulatory genes are known to function in patterning the anterior-posterior (AP) axis. This set includes the well-studied Hox cluster genes, and the recently described genes of the ParaHox cluster, which is believed to be the evolutionary sister of the Hox cluster (Brooke et al. 1998). The conserved role of these axial patterning genes in animals as diverse as frogs and flies is believed to reflect an underlying homology (i.e., all bilaterians derive from a common ancestor which possessed an AP axis and the developmental mechanisms responsible for patterning the axis). However, the origin and early evolution of Hox genes and ParaHox genes remain obscure. Repeated attempts have been made to reconstruct the early evolution of Hox genes by analyzing data from the triphoblastic animals, the Bilateria (Schubert et al. 1993; Zhang and Nei 1996). A more precise dating of Hox origins has been elusive due to a lack of sufficient information from outgroup taxa such as the phylum Cnidaria (corals, hydras, jellyfishes, and sea anemones). In combination with outgroup taxa, another potential source of information about Hox origins is outgroup genes (e.g., the genes of the ParaHox cluster). In this article, we present cDNA sequences of two Hox-like genes (anthox2 and anthox6) from the sea anemone, Nematostella vectensis. Phylogenetic analysis indicates that anthox2 (= Cnox2) is homologous to the GSX class of ParaHox genes, and anthox6 is homologous to the anterior class of Hox genes. Therefore, the origin of Hox genes and ParaHox genes occurred prior to the evolutionary split between the Cnidaria and the Bilateria and predated the evolution of the anterior-posterior axis of bilaterian animals. Our analysis also suggests that the central Hox class was invented in the bilaterian lineage, subsequent to their split from the Cnidaria. PMID:11324016

Finnerty, J R; Martindale, M Q

1999-01-01

315

Optimal locomotion of mechanical rectifier systems  

NASA Astrophysics Data System (ADS)

Vehicles utilizing animal locomotion mechanisms may possess increased performance parameters and the ability to overcome more difficult terrain than conventional wheel or propeller driven vehicles. The essential mechanism underlying animal locomotion can be viewed as mechanical rectification that converts periodic body movements to thrust force through interactions with the environment. This dissertation defines a general class of mechanical rectifiers as multi-body systems equipped with such thrust generation mechanisms. A general model is developed from the Euler-Lagrange equation and simplified by assuming small body oscillations around a given nominal posture. The model reveals that the rectifying dynamics can be captured by a bilinear (but not linear) term of body shape variables. An optimal gait problem is formulated for the bilinear rectifier model as a minimization of a quadratic cost function over the set of periodic functions subject to a constraint on the average locomotion velocity. We prove that a globally optimal solution is given by a harmonic gait that can be found by generalized eigenvalue computation with a line search over cycle frequencies. We verify the solution method through case studies of a two dimensional chain of links for which snake-like undulations and jellyfish-like flapping gaits are found to be optimal, and obtain analytical insights into determinants of optimal gaits from a simple disk-mass rectifier system. Lastly, we develop a dynamic model for batoid swimming featuring a 6 degree-of-freedom main body (position and orientation), with independent wing deformation (described as the motion of many discrete points in the body-fixed coordinate frame), and calculate various gaits. Multiple wing shapes and optimality criteria are considered, such as the maximum thrust to deflection ratio or minimum input power, and the resulting gaits are compared.

Blair, Justin T.

316

To Eat or Not to Eat? Debris Selectivity by Marine Turtles  

PubMed Central

Marine debris is a growing problem for wildlife, and has been documented to affect more than 267 species worldwide. We investigated the prevalence of marine debris ingestion in 115 sea turtles stranded in Queensland between 2006–2011, and assessed how the ingestion rates differ between species (Eretmochelys imbricata vs. Chelonia mydas) and by turtle size class (smaller oceanic feeders vs. larger benthic feeders). Concurrently, we conducted 25 beach surveys to estimate the composition of the debris present in the marine environment. Based on this proxy measurement of debris availability, we modeled turtles’ debris preferences (color and type) using a resource selection function, a method traditionally used for habitat and food selection. We found no significant difference in the overall probability of ingesting debris between the two species studied, both of which have similar life histories. Curved carapace length, however, was inversely correlated with the probability of ingesting debris; 54.5% of pelagic sized turtles had ingested debris, whereas only 25% of benthic feeding turtles were found with debris in their gastrointestinal system. Benthic and pelagic sized turtles also exhibited different selectivity ratios for debris ingestion. Benthic phase turtles had a strong selectivity for soft, clear plastic, lending support to the hypothesis that sea turtles ingest debris because it resembles natural prey items such as jellyfish. Pelagic turtles were much less selective in their feeding, though they showed a trend towards selectivity for rubber items such as balloons. Most ingested items were plastic and were positively buoyant. This study highlights the need to address increasing amounts of plastic in the marine environment, and provides evidence for the disproportionate ingestion of balloons by marine turtles. PMID:22829894

Schuyler, Qamar; Hardesty, Britta Denise; Wilcox, Chris; Townsend, Kathy

2012-01-01

317

Molluskan fasciclin-1 domain-containing protein: molecular characterizationand gene expression analysis of fasciclin 1-like protein from disk abalone (Haliotis discus discus).  

PubMed

Cell-to-cell contacts play a key role in multicellular systems and organisms. Fasciclin-1 (FAS-1) is a lipid-linked membrane associated glycoprotein that is a member of a newly recognized family of cell adhesion molecules sharing features with the immunoglobulins, cadherins, integrins, and selectins. Here, we report the identification and molecular characterization of a novel FAS-1 domain-containing cDNA from disk abalone (Haliotis discus discus), including its gene expression profile and immune response to bacterial stimuli and tissue injuries. Designated as Abfac1, the 909bp open reading frame (ORF) encodes 303 amino acid (aa) residues with a predicted molecular mass of 33kDa and isoelectric (pI) value of 4.9. The aa sequence contains two FAS-1 domains and three conserved regions, FRa motif, H-box, and FRb motif. Phylogenetic analysis showed the closest relation to Jellyfish cell adhesion protein. In healthy abalone, Abfac1 expression is highest in hepatopancreas followed by mantle and lowest in digestive gland. In immune-stimulated abalones, relative Abfac1 mRNA expression was increased in hemocytes by ~11-fold at 48h after the Vibrio parahaemolyticus infection, by 3.1-fold at 6h after the Listeria monocytogenes infection and by ~9-fold at 6h after the LPS injection. Similarly, tissue injuries caused significant increase of relative mRNA expression by 3.5-fold in hemocytes and by ~10-fold in mantle at 12h post-injury. These results suggest that the novel member of the FAS-1 domain-containing protein family, Abfac1, may be involved in immune response and cell adhesion in disk abalone. PMID:23562785

Premachandra, H K A; De Zoysa, Mahanama; Nikapitiya, Chamilani; Lee, Youngdeuk; Wickramaarachchi, W D N; Whang, Ilson; Lee, Jehee

2013-06-15

318

Hindcast and Forecast of the Black Sea Ecosystem on the Basis of 3D Interdisciplinary Model  

NASA Astrophysics Data System (ADS)

3D interdisciplinary model was used to simulate evolution of the Black Sea ecosystem during the last three decades of the 20th century. The Black Sea marine ecosystem manifested significant changes during this period of time. Healthy ecosystem which was observed in 60-ies, early 70-ies was altered drastically by the impacts of many factors. Such an evident changes in marine biology of the Black Sea were accompanied by modification of the vertical geochemical structure. The most pronounced signature of the geochemical changes was an increase of nitrate concentration in the oxic/suboxic interface zone from 2 to 3 mmol/m3 in the late 1960s to 6-9 mmol/m3 during the 1980s and 90s. The model of the Black Sea ecosystem is one way coupled with physical model and extends from the sea surface to 200m depth with 26 z-levels. The model includes 15 state variables. Phytoplankton is represented by two groups, typifying diatoms and flagellates. Zooplankton is also separated into two dimension parts: microzooplankton and mesozooplankton. The other compartments are carnivorous jelly-fish Aurelia Aurita and the ctenophore Mnemiopsis; omnivorous dinoflagellate Noctiluca; nonphotosynthetic free living bacteriaplankton; detritus and dissolved organic nitrogen. Nitrogen cycling is resolved into three inorganic forms: nitrate, nitrite and ammonium. Nitrogen is considered as the only limiting nutrients for phytoplankton growth. The geochemical part of the model is added also with oxygen and hydrogen sulfide. Fulfilled numerical experiments on modeling of the Black Sea ecosystem dynamics managed to display the main features of the pelagic ecosystem evolution during three decades 1971 - 2001, which are known from numerous measurements. For example, the phytoplankton biomass grew during the time period from early 70s until early 90s, characterized the eutrophication phase of the Black Sea ecosystem. Surface concentration of the phytoplankton in the deep part of the basin increased during this time by about 3 times. The ecosystem model was then used as a part of the Black Sea nowcasting and forecasting system, set up and developed in MHI in the framework of FP6 and FP7 projects. The further development or the Black Sea ecosystem model was its adaptation to the forecast problems, from which the most important one was initialization of the biogeochemical fields. A set of numerical experiments with assimilation of satellite chlorophyll-a data was carried out to elaborate the scheme of the Black Sea ecosystem forecast.

Dorofeyev, V.; Oguz, T.; Korotaev, G.; Sukhikh, L.

2012-04-01

319

Mass and energy transfer to seabirds in the southeastern Bering Sea  

NASA Astrophysics Data System (ADS)

It has been hypothesized that differentiation in food web structure occurs across the Bering Sea continental shelf as a result of seasonal differentiation of water masses. We tested this idea using an apex predator, pelagic birds. Seasonal abundance of birds in central Bristol Bay was estimated from counts made while underway between hydrographic stations. Prey and body mass were determined from birds collected at sea. Daily intake was estimated as an allometric function of body mass. Annual occupancy was estimated as the integral of a normal curve fit to seasonal data. Estimated carbon flux to seabirds in the middle domain was 0.12 gC m -2 y -1 in 1980, 0.18 gC m -2 y -1 in 1981. Carbon flux to seabirds in the adjacent waters of the outer shelf domain was 1.8 times higher than in the middle domain in 1980, 1.6 times higher in 1981. Carbon flux to seabirds in the inner domain was 1.2 times higher than in the middle domain in 1980, and 3.3 times higher in 1981. Carbon flux to seabirds in the outer domain was due primarily to non-diving species, principally northern fulmars ( Fulmarus glacialis) during the summer and autumn, and Larus gulls in the autumn and winter. Flux to seabirds in the inner domain was due to diving birds, principally murres ( Uria sp.) in the spring and shearwaters ( Puffinus sp.) during the summer. The euphausiid Thysanoessa raschii was the primary food source of shearwaters in shallow waters of the inner shelf domain. A more diverse set of prey, including squid, jellyfish, hyperiids, and fish, was taken by shearwaters and fulmars in the deeper waters of the outer and middle shelf domains. This result suggests that prey diversity is higher in seasonally stratified waters of outer Bristol Bay than in mixed waters of inner Bristol Bay. Greater energy flux to diving species in shallow water, and greater energy flux to non-divers in deep water may be a function of topographic control of prey patchiness.

Schneider, David C.; Hunt, George L.; Harrison, Nancy M.

320

Complex Spatial Dynamics of Oncolytic Viruses In Vitro: Mathematical and Experimental Approaches  

PubMed Central

Oncolytic viruses replicate selectively in tumor cells and can serve as targeted treatment agents. While promising results have been observed in clinical trials, consistent success of therapy remains elusive. The dynamics of virus spread through tumor cell populations has been studied both experimentally and computationally. However, a basic understanding of the principles underlying virus spread in spatially structured target cell populations has yet to be obtained. This paper studies such dynamics, using a newly constructed recombinant adenovirus type-5 (Ad5) that expresses enhanced jellyfish green fluorescent protein (EGFP), AdEGFPuci, and grows on human 293 embryonic kidney epithelial cells, allowing us to track cell numbers and spatial patterns over time. The cells are arranged in a two-dimensional setting and allow virus spread to occur only to target cells within the local neighborhood. Despite the simplicity of the setup, complex dynamics are observed. Experiments gave rise to three spatial patterns that we call “hollow ring structure”, “filled ring structure”, and “disperse pattern”. An agent-based, stochastic computational model is used to simulate and interpret the experiments. The model can reproduce the experimentally observed patterns, and identifies key parameters that determine which pattern of virus growth arises. The model is further used to study the long-term outcome of the dynamics for the different growth patterns, and to investigate conditions under which the virus population eliminates the target cells. We find that both the filled ring structure and disperse pattern of initial expansion are indicative of treatment failure, where target cells persist in the long run. The hollow ring structure is associated with either target cell extinction or low-level persistence, both of which can be viewed as treatment success. Interestingly, it is found that equilibrium properties of ordinary differential equations describing the dynamics in local neighborhoods in the agent-based model can predict the outcome of the spatial virus-cell dynamics, which has important practical implications. This analysis provides a first step towards understanding spatial oncolytic virus dynamics, upon which more detailed investigations and further complexity can be built. PMID:22719239

Wodarz, Dominik; Hofacre, Andrew; Lau, John W.; Sun, Zhiying; Fan, Hung; Komarova, Natalia L.

2012-01-01

321

RESPIRATION OF THE TISSUES OF SOME INVERTEBRATES AND ITS INHIBITION BY CYANIDE  

PubMed Central

A study of the metabolism of Bermuda marine invertebrates at 25°C. shows that the respiratory rates of many of the tissues approximate those of vertebrate tissues at the same temperature. There is no apparent correlation between respiratory rate and phylogenetic development: tissues from some of the simpler forms use as much oxygen per unit weight as those from certain of the more highly developed animals. Cyanide inhibition experiments reveal a great variation in the amount of oxygen consumption which is dependent upon sensitive heavy metal systems. Three types of tissues, the jellyfish Cassiopea frondosa, the branchial tree of the sea cucumber, Stichopus möbii, and two kinds of tunicates, were completely unaffected by even 10–2M HCN. Other tissues such as sea urchin sperm, squid gills, and lobster nerve and muscle were almost completely inhibited by much lower concentrations. Most of the materials retained 20 to 40 per cent of the normal respiratory rate in 10–2M HCN. The possibility that vanadium may play a part in the oxidation-reduction systems of the completely resistant animals is discussed. There is a thousandfold variation in the concentration of cyanide required to produce 50 per cent inhibition of respiration in the different tissues. Sea urchin sperm is 50 per cent inhibited by 10–6M HCN: the sea fan requires 10–3M for the same effect. Other tissues lie at intermediate points. When the logarithm of the ratio of the inhibited to the uninhibited respiration is plotted against the concentration of cyanide the resulting line has a slope which in most cases approximates 1. This indicates that one mole of enzyme ordinarily combines with one mole of inhibitor. Eggs of the sea urchin, Tripneustes esculentus, show a three- to fivefold increase in the rate of oxygen uptake on fertilization. The respiration of both the fertilized and unfertilized eggs is almost entirely inhibited by 10–4M HCN. Cell division in the fertilized eggs is blocked by somewhat less than 10–5M cyanide, a concentration which reduces respiration to 40 per cent of the normal level. PMID:18131869

Robbie, W. A.

1949-01-01

322

Dose-dependent Toxicity of Humanized Renilla reniformis GFP (hrGFP) Limits Its Utility as a Reporter Gene in Mouse Muscle.  

PubMed

Gene therapy has historically focused on delivering protein-coding genes to target cells or tissues using a variety of vectors. In recent years, the field has expanded to include gene-silencing strategies involving delivery of noncoding inhibitory RNAs, such as short hairpin RNAs or microRNAs (miRNAs). Often called RNA interference (RNAi) triggers, these small inhibitory RNAs are difficult or impossible to visualize in living cells or tissues. To circumvent this detection problem and ensure efficient delivery in preclinical studies, vectors can be engineered to coexpress a fluorescent reporter gene to serve as a marker of transduction. In this study, we set out to optimize adeno-associated viral (AAV) vectors capable of delivering engineered miRNAs and green fluorescent protein (GFP) reporter genes to skeletal muscle. Although the more broadly utilized enhanced GFP (eGFP) gene derived from the jellyfish, Aequorea victoria was a conventional choice, we were concerned about some previous studies suggesting this protein was myotoxic. We thus opted to test vectors carrying the humanized Renilla reniformis-derived GFP (hrGFP) gene, which has not seen as extensive usage as eGFP but was purported to be a safer and less cytotoxic alternative. Employing AAV6 vector dosages typically used in preclinical gene transfer studies (3×10(10) -1 × 10(11) particles), we found that hrGFP caused dose-dependent myopathy when delivered to wild-type (wt) mouse muscle, whereas identical titers of AAV6 carrying eGFP were relatively benign. Dose de-escalation at or below 8 × 10(9) AAV particles effectively reduced or eliminated hrGFP-associated myotoxicity, but also had dampening effects on green fluorescence and miRNA-mediated gene silencing in whole muscles. We conclude that hrGFP is impractical for use as a transduction marker in preclinical, AAV-based RNA interference therapy studies where adult mouse muscle is the target organ. Moreover, our data support that eGFP is superior to hrGFP as a reporter gene in mouse muscle. These results may impact the design of future preclinical gene therapy studies targeting muscles and non-muscle tissues alike.Molecular Therapy - Nucleic Acids (2013) 2, e86; doi:10.1038/mtna.2013.16; published online 16 April 2013. PMID:23591809

Wallace, Lindsay M; Moreo, Andrew; Clark, K Reed; Harper, Scott Q

2013-01-01

323

Reassessing regime shifts in the North Pacific: incremental climate change and commercial fishing are necessary for explaining decadal-scale biological variability.  

PubMed

In areas of the North Pacific that are largely free of overfishing, climate regime shifts - abrupt changes in modes of low-frequency climate variability - are seen as the dominant drivers of decadal-scale ecological variability. We assessed the ability of leading modes of climate variability [Pacific Decadal Oscillation (PDO), North Pacific Gyre Oscillation (NPGO), Arctic Oscillation (AO), Pacific-North American Pattern (PNA), North Pacific Index (NPI), El Niño-Southern Oscillation (ENSO)] to explain decadal-scale (1965-2008) patterns of climatic and biological variability across two North Pacific ecosystems (Gulf of Alaska and Bering Sea). Our response variables were the first principle component (PC1) of four regional climate parameters [sea surface temperature (SST), sea level pressure (SLP), freshwater input, ice cover], and PCs 1-2 of 36 biological time series [production or abundance for populations of salmon (Oncorhynchus spp.), groundfish, herring (Clupea pallasii), shrimp, and jellyfish]. We found that the climate modes alone could not explain ecological variability in the study region. Both linear models (for climate PC1) and generalized additive models (for biology PC1-2) invoking only the climate modes produced residuals with significant temporal trends, indicating that the models failed to capture coherent patterns of ecological variability. However, when the residual climate trend and a time series of commercial fishery catches were used as additional candidate variables, resulting models of biology PC1-2 satisfied assumptions of independent residuals and out-performed models constructed from the climate modes alone in terms of predictive power. As measured by effect size and Akaike weights, the residual climate trend was the most important variable for explaining biology PC1 variability, and commercial catch the most important variable for biology PC2. Patterns of climate sensitivity and exploitation history for taxa strongly associated with biology PC1-2 suggest plausible mechanistic explanations for these modeling results. Our findings suggest that, even in the absence of overfishing and in areas strongly influenced by internal climate variability, climate regime shift effects can only be understood in the context of other ecosystem perturbations. PMID:23996901

Litzow, Michael A; Mueter, Franz J; Hobday, Alistair J

2014-01-01

324

Molecular cloning and analysis of zebrafish voltage-gated sodium channel beta subunit genes: implications for the evolution of electrical signaling in vertebrates  

PubMed Central

Background Action potential generation in excitable cells such as myocytes and neurons critically depends on voltage-gated sodium channels. In mammals, sodium channels exist as macromolecular complexes that include a pore-forming alpha subunit and 1 or more modulatory beta subunits. Although alpha subunit genes have been cloned from diverse metazoans including flies, jellyfish, and humans, beta subunits have not previously been identified in any non-mammalian species. To gain further insight into the evolution of electrical signaling in vertebrates, we investigated beta subunit genes in the teleost Danio rerio (zebrafish). Results We identified and cloned single zebrafish gene homologs for beta1-beta3 (zbeta1-zbeta3) and duplicate genes for beta4 (zbeta4.1, zbeta4.2). Sodium channel beta subunit loci are similarly organized in fish and mammalian genomes. Unlike their mammalian counterparts, zbeta1 and zbeta2 subunit genes display extensive alternative splicing. Zebrafish beta subunit genes and their splice variants are differentially-expressed in excitable tissues, indicating tissue-specific regulation of zbeta1-4 expression and splicing. Co-expression of the genes encoding zbeta1 and the zebrafish sodium channel alpha subunit Nav1.5 in Chinese Hamster Ovary cells increased sodium current and altered channel gating, demonstrating functional interactions between zebrafish alpha and beta subunits. Analysis of the synteny and phylogeny of mammalian, teleost, amphibian, and avian beta subunit and related genes indicated that all extant vertebrate beta subunits are orthologous, that beta2/beta4 and beta1/beta3 share common ancestry, and that beta subunits are closely related to other proteins sharing the V-type immunoglobulin domain structure. Vertebrate sodium channel beta subunit genes were not identified in the genomes of invertebrate chordates and are unrelated to known subunits of the para sodium channel in Drosophila. Conclusion The identification of conserved orthologs to all 4 voltage-gated sodium channel beta subunit genes in zebrafish and the lack of evidence for beta subunit genes in invertebrate chordates together indicate that this gene family emerged early in vertebrate evolution, prior to the divergence of teleosts and tetrapods. The evolutionary history of sodium channel beta subunits suggests that these genes may have played a key role in the diversification and specialization of electrical signaling in early vertebrates. PMID:17623065

Chopra, Sameer S; Watanabe, Hiroshi; Zhong, Tao P; Roden, Dan M

2007-01-01

325

A zebrafish sox9 gene required for cartilage morphogenesis.  

PubMed

The molecular genetic mechanisms of cartilage construction are incompletely understood. Zebrafish embryos homozygous for jellyfish (jef) mutations show craniofacial defects and lack cartilage elements of the neurocranium, pharyngeal arches, and pectoral girdle similar to humans with campomelic dysplasia. We show that two alleles of jef contain mutations in sox9a, one of two zebrafish orthologs of the human transcription factor SOX9. A mutation induced by ethyl nitrosourea changed a conserved nucleotide at a splice junction and severely reduced splicing of sox9a transcript. A retrovirus insertion into sox9a disrupted its DNA-binding domain. Inhibiting splicing of the sox9a transcript in wild-type embryos with splice site-directed morpholino antisense oligonucleotides produced a phenotype like jef mutant larvae, and caused sox9a transcript to accumulate in the nucleus; this accumulation can serve as an assay for the efficacy of a morpholino independent of phenotype. RNase-protection assays showed that in morpholino-injected animals, the percent of splicing inhibition decreased from 80% at 28 hours post fertilization to 45% by 4 days. Homozygous mutant embryos had greatly reduced quantities of col2a1 message, the major collagen of cartilage. Analysis of dlx2 expression showed that neural crest specification and migration was normal in jef (sox9a) embryos. Confocal images of living embryos stained with BODIPY-ceramide revealed at single-cell resolution the formation of precartilage condensations in mutant embryos. Besides the lack of overt cartilage differentiation, pharyngeal arch condensations in jef (sox9a) mutants lacked three specific morphogenetic behaviors: the stacking of chondrocytes into orderly arrays, the individuation of pharyngeal cartilage organs and the proper shaping of individual cartilages. Despite the severe reduction of cartilages, analysis of titin expression showed normal muscle patterning in jef (sox9a) mutants. Likewise, calcein labeling revealed that early bone formation was largely unaffected in jef (sox9a) mutants. These studies show that jef (sox9a) is essential for both morphogenesis of condensations and overt cartilage differentiation. PMID:12397114

Yan, Yi-Lin; Miller, Craig T; Nissen, Robert M; Singer, Amy; Liu, Dong; Kirn, Anette; Draper, Bruce; Willoughby, John; Morcos, Paul A; Amsterdam, Adam; Chung, Bon-Chu; Westerfield, Monte; Haffter, Pascal; Hopkins, Nancy; Kimmel, Charles; Postlethwait, John H; Nissen, Robert

2002-11-01

326

A computational investigation of impulsive and pulsed starting annular jets  

NASA Astrophysics Data System (ADS)

A computational study is carried out on low Reynolds number impulsive and pulsating annular jets. This work is inspired by the biological flow of marine life that uses jet propulsion for self maneuver. Marine life such as squids and jellyfish propel themselves by discharging a water jet followed by a refilling phase. The discharging portion is a starting jet, i.e. the releasing of a moving fluid into a quiescent fluid, while the refilling phase can be viewed as an inflow jet. The combined jets will be called fully oscillating jets. Although fully oscillating jets have been indirectly examined experimentally, they have never been studied computationally. This dissertation is divided into three investigations that examine the starting jet, inflow jet, and fully oscillating jet based on the resultant force (i.e. either thrust or suction force) at the annulus exit plane, jet efficiency, and vortex dynamics. Furthermore, each of the following three performance criterion is examined under various velocity imposed boundaries (i.e. impulsive, unit pulsed, and sinusoidal pulsed jets), ambient pressure, and blocking ratios. An axisymmetric, incompressible and unsteady Navier Stokes numerical model was used to implement the analysis. The model was validated against theoretical and experimental results, where both result types bounded the computational results of this endeavor. In addition, numerical verification was carried out on each of the three investigations ensuring grid and time independent results. Several substantial outcomes were drawn from the results of the three investigations. The numerical results confirmed previously published experimental data regarding the universal dimensionless time scale (i.e. vortex formation number) of optimal vortex ring development triggered by starting jets. Moreover, the computational results showed evidence that the vortex formation number was not affected by ambient pressure nor blocking ratio. The computational results also confirmed earlier experimental findings that pulsed jet inflows trigger a standing vortex ring. Furthermore, the current study showed that impulsive jet inflows do not trigger vortex ring formation. In addition, unlike the expected net thrust of zero due to mass flux, fully oscillating jets showed evidence of thrust augmentation due to the enhanced entrainment caused by the vortex formation.

Abdel-Raouf, Emad Mohamed Refaat

327

Genomic organization, evolution, and expression of photoprotein and opsin genes in Mnemiopsis leidyi: a new view of ctenophore photocytes  

PubMed Central

Background Calcium-activated photoproteins are luciferase variants found in photocyte cells of bioluminescent jellyfish (Phylum Cnidaria) and comb jellies (Phylum Ctenophora). The complete genomic sequence from the ctenophore Mnemiopsis leidyi, a representative of the earliest branch of animals that emit light, provided an opportunity to examine the genome of an organism that uses this class of luciferase for bioluminescence and to look for genes involved in light reception. To determine when photoprotein genes first arose, we examined the genomic sequence from other early-branching taxa. We combined our genomic survey with gene trees, developmental expression patterns, and functional protein assays of photoproteins and opsins to provide a comprehensive view of light production and light reception in Mnemiopsis. Results The Mnemiopsis genome has 10 full-length photoprotein genes situated within two genomic clusters with high sequence conservation that are maintained due to strong purifying selection and concerted evolution. Photoprotein-like genes were also identified in the genomes of the non-luminescent sponge Amphimedon queenslandica and the non-luminescent cnidarian Nematostella vectensis, and phylogenomic analysis demonstrated that photoprotein genes arose at the base of all animals. Photoprotein gene expression in Mnemiopsis embryos begins during gastrulation in migrating precursors to photocytes and persists throughout development in the canals where photocytes reside. We identified three putative opsin genes in the Mnemiopsis genome and show that they do not group with well-known bilaterian opsin subfamilies. Interestingly, photoprotein transcripts are co-expressed with two of the putative opsins in developing photocytes. Opsin expression is also seen in the apical sensory organ. We present evidence that one opsin functions as a photopigment in vitro, absorbing light at wavelengths that overlap with peak photoprotein light emission, raising the hypothesis that light production and light reception may be functionally connected in ctenophore photocytes. We also present genomic evidence of a complete ciliary phototransduction cascade in Mnemiopsis. Conclusions This study elucidates the genomic organization, evolutionary history, and developmental expression of photoprotein and opsin genes in the ctenophore Mnemiopsis leidyi, introduces a novel dual role for ctenophore photocytes in both bioluminescence and phototransduction, and raises the possibility that light production and light reception are linked in this early-branching non-bilaterian animal. PMID:23259493

2012-01-01

328

Adaptive Control of Two-Photon Excitation of Green Fluorescent Protein with Shaped Femtosecond Pulses  

NASA Astrophysics Data System (ADS)

For many years, it has been believed that a Fourier-transform-limited (FTL) laser pulse is the most effective light source for the generation of nonlinear phenomena, since the FTL pulse has the shortest pulse duration, that is, the highest intensity, that can be limited by the spectral width due to the principle of uncertainty. Recently, many reports have been published on the adaptive control of nonlinear phenomena with shaped femtosecond excitation laser pulses [1, 2]. Their reports have shown that the modification of the spectral and temporal phases of excitation pulses can increase or decrease the probabilities and efficiencies of such nonlinear phenomena. This method has been widely applied to studies on the active control of molecular motions or chemical reactions [3,4]. Considering further novel biological applications, we focus on the two-photon excited fluorescence (TPEF) of the green fluorescent protein (GFP) from the jellyfish Aequorea victoria. GFP is spontaneously fluorescent and is relatively nontoxic compared with other organic dyes used as optical markers. Therefore, it has been widely used as a "tag" material for the fluorescence observation of living cells [5]. Two-photon excitation microscopy (TPEM) is a powerful tool for biological real-time observation due to its various advantages, such as a clear contrast, good S/N ratio, and high spatial resolution [7]. From a practical point of view, however, there is a serious problem with TPEM, which is the photobleaching of a dye. The intensity of a fluorescence signal decreases significantly during observation. One of the reasons for this is that the chromophore structure is degraded by intense excitation laser pulses that are required for efficient two-photon excitation. In this study, therefore, we attempted to determine the optimal phase for maximizing the fluorescence efficiency of a GFP variant with excitation laser pulses of minimal intensity. We considered that GFP can be an ideal dye for the investigation of the dependence of photobleaching on the phase of excitation pulses, because the GFP chromophore is located at the center of ß-can, that is, it is far from the site of reaction with activated molecular oxygen included in the solution, which can also cause photobleaching. The suppression of the photobleaching of a GFP variant in two-photon excitation is demonstrated.

Kawano, Hiroyuki; Nabekawa, Yasuo; Suda, Akira; Oishi, Yu; Mizuno, Hideaki; Miyawaki, Atsushi; Midorikawa, Katsumi

329

Transuranium radionuclide pollution in the waters of the La Maddalena National Marine Park.  

PubMed

Following the grounding and subsequent explosion, in October 2003, of a nuclear submarine in the waters of the La Maddalena National Marine Park, fears arose of possible radioactive leakages. However, isotopic analyses on algae showed that the gamma-ray emitting artificial radionuclides that one might expect to leak from a damaged nuclear reactor (such as U-235, I-131, Cs-137) were absent, and that U-238/U-234 activities were in equilibrium with values typical of sea water; this excluded any direct anthropogenic contamination as a result of the accident. We used alpha autoradiographic techniques to detect possible traces of transuranium radionuclides; 160 samples of algae, granites, sea urchins, gastropods, limpets, cuttlefish and jellyfish were collected from the area, as well as from other Mediterranean coastlines and the Baltic Sea. All samples were autoradiographed, and selected samples further analysed by alpha spectrometry. There were no alpha track concentrations above background levels in our control Mediterranean specimens. In the samples from the La Maddalena and Baltic areas two different track distributions were observed: --those homogeneously distributed over the surfaces examined; --groups (10 to over 500) of radially distributed alpha tracks (forming "star" bursts, or "hot spots") emanating from point sources. By comparing radionuclide activities measured by alpha spectroscopy with alpha track densities, we extrapolated Pu activities for all samples. About 74% of algae had Pu activities of less than 1 Bq/kg and 0.25 Bq/kg, 16% had accumulated Pu to levels between 1 and 2 Bq/kg, and a very few specimens had concentrations between 2 and 6 Bq/kg. Plots showed that alpha tracks and stars concentrate around the northern and eastern margins of the Rada (Basin) di Santo Stefano, sites facing the nuclear submarine base on the eastern shore of the island of Santo Stefano. What is the source of these nuclides: last century's atmospheric nuclear testing, Chernobyl or a local source? Their concentrated, extremely localised occurrence seems difficult to explain in terms of left-over worldwide nuclear pollution. A local source seems more plausible. PMID:15829338

Aumento, F; Le Donne, K; Eroe, K

2005-01-01

330

Science Underlying 2008 Nobel Prizes  

NASA Astrophysics Data System (ADS)

JCE offers a wealth of materials for teaching and learning chemistry that you can explore online. In the list below, Bernadette Caldwell of the Editorial Staff suggests additional resources that are available through JCE for teaching the science behind some of the 2008 Nobel Prizes . Discovering and Applying the Chemistry of GFP The Royal Swedish Academy of Sciences awarded the 2008 Nobel Prize in Chemistry for the discovery and development of the green fluorescent protein, GFP to three scientists: Osamu Shimomura, Martin Chalfie, and Roger Y. Tsien. These scientists led the field in discovering and introducing a fluorescing protein from jellyfish into cells and genes under study, which allows researchers to witness biochemistry in action. Now tags are available that emit light in different colors, revealing myriad biological processes and their interactions simultaneously. Identifying HPV and HIV, HIV's Replication Cycle, and HIV Virus-Host Interactions The Nobel Assembly at Karolinska Institutet awarded the 2008 Nobel Prize in Medicine or Physiology for their discovery of human immunodeficiency virus (HIV) to two scientists: Françoise Barré-Sinoussi and Luc Montagnier; and for his discovery of human papilloma viruses [HPV] causing cervical cancer to one scientist, Harald zur Hausen. Diseases caused by these infectious agents significantly affect global health. While isolating and studying the virus, researchers discovered HIV is an uncommon retrovirus that infects humans and relies on the host to make its viral DNA, infecting and killing the host's white blood cells, ultimately destroying the immune systems of infected humans. Related Resources at JCE Online The Journal has published articles relating to GFP specifically, and more generally to fluorescing compounds applied to biochemistry. The Journal has also published an article and a video on protease inhibition—a strategy to suppress HIV's biological processes. With the video clips, an accompanying guide for teachers includes instructions for three student activities that use enzymes. The resources below may help introduce students to the science behind some of these Nobel Prizes. Turning on the Light: Lessons from Luminescence. O'Hara, P. B.; Engelson, C.; St. Peter, W. J. Chem. Educ. 2005, 82, 49 . (See especially the bioluminescence section on page 51 that concisely explains GFP.) JCE Classroom Activity #68: Turning on the Light. O'Hara, P. B.; Engelson, C.; St. Peter, W. J. Chem. Educ. 2005, 82, 48A . JCE Classroom Activity #81: pHantastic Fluorescence. Muyskens, M. J. Chem. Educ. 2006, 83, 768A . Recombinant Green Fluorescent Protein Isoforms: Exercises To Integrate Molecular Biology, Biochemistry, and Biophysical Chemistry. Hicks, B. W. J. Chem. Educ. 1999, 76, 409 . C-SNARF-1 as a Fluorescent Probe for pH Measurements in Living Cells: Two-Wavelength-Ratio Method versus Whole-Spectral-Resolution Method. Ribou, A-C.; Vigo, J.; Salmon, J-M. J. Chem. Educ. 2002, 79, 1471 . An Attack on the AIDS Virus: Inhibition of the HIV-1 Protease: New Drug Development Based on the Structure and Activity of the Protease and Its Role in the Replication and Maturation of the Virus. Volker, E. J. J. Chem. Educ. 1993, 70, 3 . From Chemistry Comes Alive!, five video clips demonstrate properties and mechanisms involved in the chemistry of HIV. HIV-1 Protease: An Enzyme at Work . All articles from Volume 1 to the current issue are available in full-text PDF at JCE Online : Browse by year, month, and page , or choose title and author searching of all issues of JCE.

Caldwell, Bernadette A.

2009-01-01

331

My school voyages with PERSEUS - PERSEUS@SCHOOL  

NASA Astrophysics Data System (ADS)

PERSEUS@SCHOOL is an international environmental education thematic school network which is inspired and supported by the European research project PERSEUS (Policy Oriented Marine Environmental Research in Southern European Seas_http://www.perseus-net.eu) which is funded by EU FP7 Theme "Ocean of Tomorrow" and it is coordinating by the Hellenic Centre for Marine Research (HCMR). The overall scientific objectives of PERSEUS (FP7) research project are to identify the interacting patterns of natural and human-derived pressures on the Mediterranean and Black Seas, assess their impact on marine ecosystems and, using the objectives and principles of the Marine Strategy Framework Directive as a vehicle, to design an effective and innovative research governance framework based on solid scientific knowledge. This research governance framework will engage scientists, policy-makers and the public, thereby reaching a shared understanding and informed decision-making based on sound scientific knowledge. PERSEUS@SCHOOL network is coordinated by the Department of Environmental Education of the 1st Directorate of Secondary Education of Athens and aims to help and enhance environmental education, focusing on clean seas stewardship in schools. Educators along with marine scientists have a role in supporting and inspiring children to acquire the knowledge, skills and inspire their awareness to live and work as responsible and concerned citizens. For this purpose, the network has designed specific pedagogical activities for primary and secondary education - based on PERSEUS key thematic areas i.e. Marine biodiversity, Overfishing, Chemical Marine Pollution - Bioaccumulation - Health, Eutrophication in Marine Waters and Marine Litter. Complementary, two web-monitoring tools will be used by the network; the Jellyfish Spotting campaign and the Marine LitterWatch (MLW) app (Developed by EEA). A special emphasis is given to MLW app, as school students for first time will use it in order to test this new tool and to monitor beach marine litter in selected areas in Greece. The pedagogical activities of the network will give students an opportunity to explore similarities and differences between schools and nationalities, while simultaneously creating awareness of other young people's reality in a captivating way. PERSEUS@SCHOOL will allow students to use their imagination and knowledge provided by PERSEUS scientists, in order to think and act about the marine environment and its protection in an interactive, appealing and imaginative way. Finally, students will participate in a "true" expedition in the Aegean Sea, on the R/V AEGAEO of the Hellenic Centre for Marine Research (HCMR). The aim of this expedition is to involve students in marine scientific research and guide them to recognize the 'value' of the Mediterranean Sea and the threats and challenges it faces in the modern world. During this expedition, students will collaborate with marine scientists creating a powerful interactive learning experience, participate in experiments, interpret research findings, draw conclusions and voice their opinion for the "Oceans of tomorrow".

Fermeli, Georgia; Papathanassiou, Evangelos; Papatheodorou, George; Streftaris, Nikos; Ioakeimidis, Christos

2014-05-01

332

Another Nobel Prize linked to synchrotron radiation work  

SciTech Connect

The 2008 Nobel Prize in Chemistry went to Osamu Shimomura, Martin Chalfie and Roger Tsien 'for the discovery and development of the green fluorescent protein, GFP'. This year's Nobel Prize in Chemistry rewards the initial discovery of GFP and a series of important developments which have led to its use as a tagging tool in bioscience. By using DNA technology, researchers can now connect GFP to other interesting, but otherwise invisible, proteins. This glowing marker allows the movements, positions and interactions of the tagged proteins to be monitored. Osamu Shimomura was the first to isolate GFP from the jellyfish Aequorea victoria, found off the west coast of North America, and discovered the protein's green glow [Shimomura et al. (1962). J. Cell. Comp. Physiol. 59, 223-240]. Martin Chalfie demonstrated the value of GFP as a luminous genetic tag. In one of his first experiments he coloured six individual cells in the transparent roundworm Caenorhabditis elegans with the aid of GFP. He had obtained the GFP gene (gfp) clone from Prasher [Prasher et al. (1992). Gene, 111, 229-233] and expressed it in E. coli. The GFP protein displayed a bright green fluorescence in this heterologous organism, suggesting that it could indeed serve as a versatile genetic marker in virtually all organisms. Chalfie transformed C. elegans with gfp under the control of a promoter regulating the expression of {beta}-tubulin, abundant in six touch receptor neurons in C. elegans. The organism subsequently expressed GFP from distinct positions in its body and at distinct times in its development [Chalfie et al. (1994). Science, 263, 802-805]. Roger Tsien contributed to the general understanding of how GFP glows by determining the formation of the GFP chromophore, a chemical group that absorbs and emits light. Tsien is best known for extending the colour palette of GFP beyond green, allowing researchers to follow several different biological processes at the same time. According to background on the Nobel Prize website, 'An important step forward, allowing for rational design of mutants, was the solution of the crystal structure of GFP.' Tsien collaborated with Jim Remington and his team who solved the structure of GFP at 1.9 {angstrom} using data in part collected at NSLS beamline X4A. Tsien and Remington were able to use the structural information and design specific mutants (Thr203, to Tyr or His) which resulted in significantly red-shifted excitation and emission maxima and thus converting GFP into YFP (yellow fluorescence protein) [Ormo et al. (1996). Science, 273, 1392-1395]. Acknowledging the contribution of NSLS Brookhaven, University of Oregon scientist Remington said 'The data collected at beamline X4A were essential to solve the structure of GFP. We were unable to solve the structure using native and heavy-atom-derivative data sets collected at home'. Remington added 'In those days the technology to flash freeze crystals had not been fully worked out and so diffraction data had to be collected at temperatures above freezing. Crystal lifetime was very short. At X4A, a crystal cooling system enabled data collection at close to zero degrees Celsius, extending the crystal lifetime, while the intense beam permitted data to be collected at significantly higher resolution. In addition, the tunable nature of the source allowed us to collect data at the selenomethionine absorption edge, which dramatically improved the signal for phasing purposes. The improved phasing, combined with higher resolution data, resulted in an interpretable electron density map. The first look at the GFP chromophore in that electron density map was one of the most exciting moments of my entire career.'

Hasnain, S.

2009-01-01

333

Interaction of pressure and momentum driven flows with thin porous media: Experiments and modeling  

NASA Astrophysics Data System (ADS)

Flow interaction with thin porous media arise in a variety of natural and man-made settings. Examples include flow through thin grids in electronics cooling, and NOx emissions reduction by means of ammonia injection grids, pulsatile aquatic propulsion with complex trailing anatomy (e.g., jellyfish with tentacles) and microbursts from thunderstorm activity over dense vegetation, unsteady combustion in or near porous materials, pulsatile jet-drying of textiles, and pulsed jet agitation of clothing for trace contaminant sampling. Two types of interactions with thin porous media are considered: (i) forced convection or pressure-driven flows, where fluid advection is maintained by external forces, and (ii) inertial or momentum-driven flows, in which fluid motion is generated but not maintained by external forces. Forced convection analysis through thin permeable media using a porous continuum approach requires the knowledge of porous medium permeability and form coefficients, K and C, respectively, which are defined by the Hazen-Dupuit-Darcy (HDD) equation. Their determination, however, requires the measurement of the pressure-drop per unit of porous medium length. The pressure-drop caused by fluid entering and exiting the porous medium, however, is not related to the porous medium length. Hence, for situations in which the inlet and outlet pressure-drops are not negligible, e.g., for short porous media, the definition of Kand C via the HDD equation becomes ambiguous. This aspect is investigated analytically and numerically using the flow through a restriction in circular pipe and parallel plates channels as preliminary models. Results show that inlet and outlet pressure-drop effects become increasingly important when the inlet and outlet fluid surface fraction ? decreases and the Reynolds number Re increases for both laminar and turbulent flow regimes. A conservative estimate of the minimum porous medium length beyond which the core pressure-drop predominates over the inlet and outlet pressure-drop is obtained by considering a least restrictive porous medium core. Finally, modified K and C are proposed and predictive equations, accurate to within 2.5%, are obtained for both channel configurations with Re ranging from 10-2 to 102 and ? from 6% to 95%. When momentum driven flows interact with thin porous media, the interaction of vortices with the media's complex structure gives way to a number of phenomena of fundamental and applied interest, such as unsteady flow separation. A special case that embodies many of the key features of these flows is the interaction of a vortex ring with a permeable flat surface. Although fundamental, this complex flow configuration has never been considered. The present investigation experimentally studies the fluid mechanics of the interaction of a vortex ring impinging directly on thin permeable flat targets. The vortex ring is formed in water using a piston-cylinder mechanism and visualized using planar laser-induced fluorescence (PLIF). The rings are formed for jet Reynolds numbers of 3000 and 6000, and piston stroke-to-diameter ratios of 1.0, 3.0, and 6.0. Thin screens of similar geometry having surface opening fractions of 44, 60, 69, and 79% are targeted by the rings. The flow that emerges downstream of the screens reforms into a new, "transmitted" vortex ring. For the lower porosity targets, features that are characteristic of vortex ring impingement on walls are also observed, such as primary vortex ring rebound and reversal, flow separation, formation of secondary vortices and mixing. As the interaction proceeds, however, the primary vortex ring and secondary vortices are drawn toward the symmetry axis of the flow by fluid passing through the permeable screen. Quantitative flow measurements using digital particle image velocimetry (DPIV), indicate the transmitted vortex ring has lower velocity and less (total) kinetic energy than the incident ring. Ring trajectories and total kinetic energy relationships between vortices upstream and downstream the porous targets as a funct

Naaktgeboren, Christian