نتایج جستجو برای: sea urchin

تعداد نتایج: 130365  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1983
J W Roberts J W Grula J W Posakony R Hudspeth E H Davidson R J Britten

Clones of full-length mtDNA have been isolated from a Strongylocentrotus franciscanus recombinant DNA library by screening a cDNA clone of cytochrome oxidase subunit 1 mRNA. Restriction fragment cross-hybridization analysis shows the following difference in gene arrangement between sea urchin and human mtDNA. The 16S rRNA and cytochrome oxidase subunit 1 genes are directly adjacent in sea urchi...

Journal: :Journal of travel medicine 2000
N Liram M Gomori M Perouansky

Of the 600 species of sea urchins, approximately 80 may be venomous to humans. The long spined or black sea urchin, Diadema setosum may cause damage by the breaking off of its brittle spines after they penetrate the skin. Synovitis followed by arthritis may be an unusual but apparently not a rare sequel to such injury, when implantation occurs near a joint. In this case report, osseous changes ...

2007
Paolo Guidetti Enric Sala

We investigated the community-wide effects of no-take marine reserves at the regional scale in the Mediterranean Sea. Reserves had general positive effects of protection on fish targeted by fishing, and variable effects on non-target species. Differences in the structure of fish assemblages (in terms of abundance of species and trophic groups) were greater between geographic locations than when...

2011
S. Clemente

We studied the effects of marine protected areas (MPAs) on predatory interactions at a regional scale of 3 different islands across the geographical gradient of the Canary Islands. Protection measures positively affected predatory fish assemblages, enhancing the intensity of predatory interactions in comparison to equivalent unprotected areas (UAs), and causing indirect effects on populations o...

2006
M. J. Tegner K. Dayton

Southern California kelp forests experienced major losses during the El Nino of 1957-1959. The proximal reason for the decline was ascribed to sea urchin grazing, and the eventual recovery of some forests followed sea urchin control efforts, kelp restoration, and improvements In sewage disposal practices. The very strong El Nirio of 1982-84 allowed us to reexamine hypotheses regarding the inter...

E. Mohammadi , E. Sadripour , F. Ghassemzadeh , M. S. Mortazavi , M. Soltani , N. Mahdavi Shahri, V. Ghorani,

Sea Urchin is one of the most useful tools in developmental biology studies because this organism has the simplest kind of developmental stages. We aimed to determine developmental stages and timetable of Echinometra mathaei embryo (the species of Persian Gulf). The spawning of E. mathaei was induced by 0.5M KCl injection (1ml) into the coelomic cavity. After fertilization, embryos wer...

Journal: :Developmental biology 2003
Ekaterina Voronina William F Marzluff Gary M Wessel

Sea urchins are members of a limited group of animals in which meiotic maturation of oocytes is completed prior to fertilization. This is different from oocytes of most animals such as mammals and amphibians in which fertilization reactivates an arrested meiotic cycle. Using a recently developed technique for in vitro maturation of sea urchin oocytes, we analyzed the role of cyclin B, the regul...

Journal: :The Journal of experimental biology 2012
Shigeru Kawamata

Algal mats can hinder the adhesion of the tube feet of sea urchins. This leads to the hypothesis that the restriction of sea urchin feeding activity by wave action can potentially be enhanced by the presence of algal mats, which will facilitate the survival of kelp recruits at sites with wave action in urchin barrens. To evaluate the potential anti-attachment effect of algal mats on sea urchins...

Journal: :The Journal of experimental biology 1950
H BARNES ROTHSCHILD

INTRODUCTION The addition of copper salts to dense suspensions of unwashed sea-urchin spermatozoa in sea water markedly stimulates the O2 uptake of the suspension (Rothschild & Tuft, 1950). An investigation of the Cu content of sea-urchin semen and seminal plasma was therefore of interest and is the subject of this note. At the same time the coelomic fluid of Echinus esculentus and sea water we...

Journal: :The Journal of biological chemistry 2009
Michelle O Castro Vitor H Pomin Livia L Santos Ana-Cristina E S Vilela-Silva Noritaka Hirohashi Laércio Pol-Fachin Hugo Verli Paulo A S Mourão

Sulfated polysaccharides from the egg jelly of sea urchins act as species-specific inducers of the sperm acrosome reaction, which is a rare molecular mechanism of carbohydrate-induced signal-transduction event in animal cells. The sea urchin polysaccharides differ in monosaccharide composition (l-fucose or l-galactose), glycosylation, and sulfation sites, but they are always in the alpha-anomer...

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