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https://www.readbyqxmd.com/read/28091726/predation-cues-rather-than-resource-availability-promote-cryptic-behaviour-in-a-habitat-forming-sea-urchin
#1
Arie J P Spyksma, Richard B Taylor, Nick T Shears
It is well known that predators often influence the foraging behaviour of prey through the so-called "fear effect". However, it is also possible that predators could change prey behaviour indirectly by altering the prey's food supply through a trophic cascade. The predator-sea urchin-kelp trophic cascade is widely assumed to be driven by the removal of sea urchins by predators, but changes in sea urchin behaviour in response to predators or increased food availability could also play an important role. We tested whether increased crevice occupancy by herbivorous sea urchins in the presence of abundant predatory fishes and lobsters is a response to the increased risk of predation, or an indirect response to higher kelp abundances...
January 13, 2017: Oecologia
https://www.readbyqxmd.com/read/28091127/amino-modified-polystyrene-nanoparticles-affect-signalling-pathways-of-the-sea-urchin-paracentrotus-lividus-embryos
#2
Annalisa Pinsino, Elisa Bergami, Camilla Della Torre, Maria Luisa Vannuccini, Piero Addis, Marco Secci, Kenneth A Dawson, Valeria Matranga, Ilaria Corsi
Polystyrene nanoparticles have been shown to pose serious risk to marine organisms including sea urchin embryos based on their surface properties and consequently behaviour in natural sea water. The aim of this study is to investigate the toxicity pathways of amino polystyrene nanoparticles (PS-NH2, 50 nm) in Paracentrotus lividus embryos in terms of development and signalling at both protein and gene levels. Two sub-lethal concentrations of 3 and 4 µg/mL of PS-NH2 were used to expose sea urchin embryos in natural sea water (PS-NH2 as aggregates of 143 ± 5 nm)...
January 16, 2017: Nanotoxicology
https://www.readbyqxmd.com/read/28089513/human-disruption-of-coral-reef-trophic-structure
#3
Nicholas A J Graham, Tim R McClanahan, M Aaron MacNeil, Shaun K Wilson, Joshua E Cinner, Cindy Huchery, Thomas H Holmes
The distribution of biomass among trophic levels provides a theoretical basis for understanding energy flow and the hierarchical structure of animal communities. In the absence of energy subsidies [1], bottom-heavy trophic pyramids are expected to predominate, based on energy transfer efficiency [2] and empirical evidence from multiple ecosystems [3]. However, the predicted pyramid of biomass distribution among trophic levels may be disrupted through trophic replacement by alternative organisms in the ecosystem, trophic cascades, and humans preferentially impacting specific trophic levels [4-6]...
January 9, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28088316/individual-female-differences-in-chemoattractant-production-change-the-scale-of-sea-urchin-gamete-interactions
#4
Yasmeen H Hussain, Martin Sadilek, Shukri Salad, Richard K Zimmer, Jeffrey A Riffell
Sperm selection by females is an important process influencing fertilization and, particularly in broadcast-spawning organisms, often occurs before sperm reach the egg. Waterborne sperm chemoattractants are one mechanism by which eggs selectively influence conspecific sperm behavior, but it remains an open question whether the eggs from different females produce different amounts of sperm chemoattractant, and how that might influence sperm behavior. Here, we quantify the differences in attractant production between females of the sea urchin species Lytechinus pictus and use computational models and microfluidic sperm chemotaxis assays to determine how differences in chemoattractant production between females affects their ability to attract sperm...
January 11, 2017: Developmental Biology
https://www.readbyqxmd.com/read/28087654/effects-of-external-strain-on-the-regulation-of-microtubule-sliding-induced-by-outer-arm-dynein-of-sea-urchin-sperm-flagella
#5
Hiroshi Yoke, Chikako Shingyoji
Oscillatory bending movement of eukaryotic flagella is powered by orchestrated activity of dynein motor proteins that hydrolyze ATP and produce microtubule sliding. Although the ATP concentration within a flagellum is kept uniform at a few mmol l(-1) level, sliding activities of dyneins are dynamically coordinated along the flagellum in accordance with the phase of bending waves. Thus, at the organellar level the dynein not only generates force for bending but also modulates its motile activity by responding to bending of the flagellum...
January 13, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28080914/tricaine-methanesulfonate-ms-222-sedation-and-anesthesia-in-the-purple-spined-sea-urchin-arbacia-punctulata
#6
Jeffrey R Applegate, Daniel S Dombrowski, Larry Shane Christian, Meredith P Bayer, Craig A Harms, Gregory A Lewbart
The purple-spined sea urchin ( Arbacia punctulata ) is commonly found in shallow waters of the western Atlantic Ocean from the New England area of the United States to the Caribbean. Sea urchins play a major role in ocean ecology, echinoculture, and biomedical research. Additionally, sea urchins are commonly displayed in public aquaria. Baseline parameters were developed in unanesthetized urchins for righting reflex (time to regain oral recumbency) and spine response time to tactile stimulus. Tricaine methanesulfonate (MS-222) was used to sedate and anesthetize purple-spined sea urchins and assess sedation and anesthetic parameters, including adhesion to and release from a vertical surface, times to loss of response to tactile stimulus and recovery of righting reflex, and qualitative observations of induction of spawning and position of spines and pseudopodia...
December 2016: Journal of Zoo and Wildlife Medicine: Official Publication of the American Association of Zoo Veterinarians
https://www.readbyqxmd.com/read/28075025/warmer-temperatures-reduce-the-influence-of-an-important-keystone-predator
#7
Chiara Bonaviri, Michael Graham, Paola Gianguzza, Nick T Shears
Predator-prey interactions may be strongly influenced by temperature variations in marine ecosystems. Consequently, climate change may alter the importance of predators with repercussions for ecosystem functioning and structure. In North-eastern Pacific kelp forests, the starfish Pycnopodia helianthoides is known to be an important predator of the purple sea urchin Strongylocentrotus purpuratus. Here we investigated the influence of water temperature on this predator-prey interaction by: (1) assessing the spatial distribution and temporal dynamics of both species across a temperature gradient in the northern Channel Islands, California, and (2) investigating how the feeding rate of P...
January 11, 2017: Journal of Animal Ecology
https://www.readbyqxmd.com/read/28073275/highly-efficient-retention-of-polysulfides-in-sea-urchin-like-carbon-nanotube-nanopolyhedra-superstructures-as-cathode-material-for-ultralong-life-lithium-sulfur-batteries
#8
Tao Chen, Baorui Cheng, Guoyin Zhu, Renpeng Chen, Yi Hu, Lianbo Ma, Hongling Lv, Yanrong Wang, Jia Liang, Zuoxiu Tie, Zhong Jin, Jie Liu
Despite high theoretical energy density, the practical deployment of lithium-sulfur (Li-S) batteries is still not implemented because of the severe capacity decay caused by polysulfide shuttling and the poor rate capability induced by low electrical conductivity of sulfur. Herein, we report a novel sulfur host material based on "sea urchin"-like cobalt nanoparticle embedded and nitrogen-doped carbon nanotube/nanopolyhedra (Co-NCNT/NP) superstructures for Li-S batteries. The hierarchical micromesopores in Co-NCNT/NP can allow efficient impregnation of sulfur and block diffusion of soluble polysulfides by physical confinement, and the incorporation of embedded Co nanoparticles and nitrogen doping (∼4...
January 11, 2017: Nano Letters
https://www.readbyqxmd.com/read/28068608/designing-of-carbon-based-fluorescent-nanosea-urchin-via-green-synthesis-approach-for-live-cell-detection-of-zinc-oxide-nanoparticle
#9
Raksha Choudhary, Santanu Patra, Rashmi Madhuri, Prashant K Sharma
The present work reports an eco-friendly and economic method for the preparation of different shaped (spherical, rod, and sea-urchin) heteroatom-doped fluorescent carbon nanoparticles (CNPs) by a unique combination of sonochemical, microwave and hydrothermal approach. Not only in terms of chemical, herein, we used the green precursors i.e. six members from solonaceae family for the synthesis of CNPs. Among the various shapes of CNPs, the sea-urchin shape CNPs (SU-CNPs) shows the high product and quantum yield with good photostability, excellent water dispersibility, narrow size distribution and high storage ability...
December 31, 2016: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28065307/analysis-of-cytokinesis-by-electron-microscopy
#10
J König, J Borrego-Pinto, D Streichert, M Munzig, P Lenart, T Müller-Reichert
Following up on a chapter on the Correlative Light and Electron Microscopy of Early Caenorhabditis elegans Embryos in Mitosis (MCB 79, 101-119), we present an adaptation of our established protocol for the ultrastructural analysis of either permeabilized or injected embryonic systems. We prepared both drug-treated early C. elegans embryos and fluorescently labeled sea urchin embryos of Lytechinus pictus for ultrastructural studies on animal cytokinesis. Here we focus on the initial preparation steps of postmitotic embryos for high-pressure freezing and subsequent electron microscopy with an emphasis on electron tomography...
2017: Methods in Cell Biology
https://www.readbyqxmd.com/read/28065299/labeling-membrane-domains-in-dividing-echinoderm-eggs
#11
M Bennett, J Meaders, S Ruvolo, D Burgess
Sea urchins have long been used as a model organism to address questions in cell biology and development. Work utilizing this model has elucidated processes of fertilization, the description of centrosomes, the separation of chromosomes during mitosis, and numerous other landmark discoveries. They have been a favorite among researchers for a variety of reasons: Eggs are large and malleable, making them relatively easy to work with; the embryos have synchronized, rapid divisions; they are easy to microinject and manipulate; and their genome sequence is available...
2017: Methods in Cell Biology
https://www.readbyqxmd.com/read/28062561/sperm-sensory-signaling
#12
Dagmar Wachten, Jan F Jikeli, U Benjamin Kaupp
Fertilization is exceptionally complex and, depending on the species, happens in entirely different environments. External fertilizers in aquatic habitats, like marine invertebrates or fish, release their gametes into the seawater or freshwater, whereas sperm from most internal fertilizers like mammals cross the female genital tract to make their way to the egg. Various chemical and physical cues guide sperm to the egg. Quite generally, these cues enable signaling pathways that ultimately evoke a cellular Ca(2+) response that modulates the waveform of the flagellar beat and, hence, the swimming path...
January 6, 2017: Cold Spring Harbor Perspectives in Biology
https://www.readbyqxmd.com/read/28062237/physico-chemical-characterization-and-pharmacological-activities-of-sulfated-polysaccharide-from-sea-urchin-paracentrotus-lividus
#13
Yosra Ben Salem, Safa Amri, Khaoula Mkadmini Hammi, Amal Abdelhamid, Didier Le Cerf, Abderrahman Bouraoui, Hatem Majdoub
Sulfated polysaccharide (SP) from the eggs of sea urchin Paracentrotus lividus, extracted by papain digestion, was characterized by size exclusion chromatography coupling on-line with light scattering and viscosity detectors (SEC/MALS/VD/DRI), gas chromatography coupled to mass spectrometer (GC-MS), and Fourier transform infrared spectroscopy (FTIR) analysis. The native molecular mass of the extracted polysaccharide is high (≥22 000 KDa) and it is composed mainly of arabinose, accompanied by other monosaccharides (mostly galactose, glucose and fucose), significant amounts of uronic acids (18...
January 3, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28057763/the-ultrastructural-organization-of-actin-and-myosin-ii-filaments-in-the-contractile-ring-new-support-for-an-old-model-of-cytokinesis
#14
John H Henson, Casey E Ditzler, Aphnie Germain, Patrick M Irwin, Eric T Vogt, Shucheng Yang, Xufeng Wu, Charles B Shuster
Despite recent advances in our understanding of the components and spatial regulation of the contractile ring (CR), the precise ultrastructure of actin and myosin II within the animal cell CR remains an unanswered question. We employed super-resolution light microscopy and platinum replica transmission electron microscopy (TEM) to determine the structural organization of actin and myosin II in isolated cortical cytoskeletons prepared from dividing sea urchin embryos. 3D structured illumination microscopy (SIM) indicated that within the CR, actin and myosin II filaments were organized into tightly packed linear arrays oriented along the axis of constriction, and restricted to a narrow zone within the furrow...
January 5, 2017: Molecular Biology of the Cell
https://www.readbyqxmd.com/read/28056208/the-effect-of-photobiomodulation-on-the-sea-urchin-paracentrotus-lividus-echinodermata-by-using-higher-fluence-on-fertilization-embryogenesis-and-larval-development-an-in-vitro-study
#15
Andrea Amaroli, Chiara Gambardella, Sara Ferrando, Reem Hanna, Alberico Benedicenti, Lorenzo Gallus, Marco Faimali, Stefano Benedicenti
OBJECTIVE: The aim of this study was to investigate the photobiomodulation (PBM) effect of the 808 nm diode laser irradiation on spermatozoa, eggs, fertilized eggs, embryos, and larvae of Paracentrotus lividus, using two different power settings. BACKGROUND DATA: Studies have shown the possible use of PBM in artificial insemination. These have shown the potential effect of low-power laser irradiation on spermatozoa, while there are few studies on the effect of laser photonic energy on oocytes and almost no reports on the influence of lasers in embryogenesis...
December 30, 2016: Photomedicine and Laser Surgery
https://www.readbyqxmd.com/read/28052391/the-present-is-the-key-to-the-past-linking-regime-shifts-in-kelp-beds-to-the-distribution-of-deep-living-sea-urchins
#16
Karen Filbee-Dexter, Robert E Scheibling
Understanding processes that drive sudden shifts in ecosystem structure and function has become an important research focus for coastal management. In kelp bed ecosystems, regime shifts occur when high densities of sea urchins destructively graze kelp and create coralline algal barrens. While the importance of predation and disease in mediating shifts between kelp beds and barrens on shallow rocky reefs has been well documented, little is known about the role of deep-living urchins in these alternative stable-state dynamics...
January 2017: Ecology
https://www.readbyqxmd.com/read/28052125/biosynthesis-of-polyunsaturated-fatty-acids-in-sea-urchins-molecular-and-functional-characterisation-of-three-fatty-acyl-desaturases-from-paracentrotus-lividus-lamark-1816
#17
Naoki Kabeya, Alicia Sanz-Jorquera, Stefano Carboni, Andrew Davie, Angela Oboh, Oscar Monroig
Sea urchins are broadly recognised as a delicacy and their quality as food for humans is highly influenced by their diet. Lipids in general and the long-chain polyunsaturated fatty acids (LC-PUFA) in particular, are essential nutrients that determine not only the nutritional value of sea urchins but also guarantee normal growth and reproduction in captivity. The contribution of endogenous production (biosynthesis) of LC-PUFA in sea urchins remained unknown. Using Paracentrotus lividus as our model species, we aimed to characterise both molecularly and functionally the repertoire of fatty acyl desaturases (Fads), key enzymes in the biosynthesis of LC-PUFA, in sea urchins...
2017: PloS One
https://www.readbyqxmd.com/read/28040812/aquatic-antagonists-cutaneous-sea-urchin-spine-injury
#18
Clifford Hsieh, Erica R Aronson, Arlene M Ruiz de Luzuriaga
Injuries from sea urchin spines are commonly seen in coastal regions with high levels of participation in water activities. Although these injuries may seem minor, the consequences vary based on the location of the injury. Sea urchin spine injuries may cause arthritis and synovitis from spines in the joints. Nonjoint injuries have been reported, and dermatologic aspects of sea urchin spine injuries rarely have been discussed. We present a case of a patient with sea urchin spines embedded in the thigh who subsequently developed painful skin nodules...
November 2016: Cutis; Cutaneous Medicine for the Practitioner
https://www.readbyqxmd.com/read/28033013/photo-controlled-supramolecular-assembling-of-azobenzene-based-biscalix-4-arenes-upon-starting-and-stopping-laser-trapping
#19
Ken-Ichi Yuyama, Lionel Marcélis, Pei-Mei Su, Wen-Sheng Chung, Hiroshi Masuhara
Laser trapping in chemistry covers various studies from single molecules, nanoparticles, and quantum dots to crystallization and liquid-liquid phase separation of amino acids. In this work, a supramolecular assembly of azobenzene-based biscalix[4]arene is generated in ethyl acetate by laser trapping; its nucleation and growth are elucidated. No trapping behavior was observed when a 1064 nm laser beam was focused inside the solution; however, interesting assembling phenomena were induced when it was shined at the air/solution interface...
December 29, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28030596/phase-shift-dynamics-of-sea-urchin-overgrazing-on-nutrified-reefs
#20
Nina Kriegisch, Simon Reeves, Craig R Johnson, Scott D Ling
Shifts from productive kelp beds to impoverished sea urchin barrens occur globally and represent a wholesale change to the ecology of sub-tidal temperate reefs. Although the theory of shifts between alternative stable states is well advanced, there are few field studies detailing the dynamics of these kinds of transitions. In this study, sea urchin herbivory (a 'top-down' driver of ecosystems) was manipulated over 12 months to estimate (1) the sea urchin density at which kelp beds collapse to sea urchin barrens, and (2) the minimum sea urchin density required to maintain urchin barrens on experimental reefs in the urbanised Port Phillip Bay, Australia...
2016: PloS One
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