نتایج جستجو برای: echinodermata
تعداد نتایج: 1451 فیلتر نتایج به سال:
The huge potential of echinoderms as a so far fairly untapped source of bioactive molecules is described. Examples are presented that show the usefulness of echinoderm-derived molecules for therapeutic application in selected fields of cancer research, in the control of bacterial growth as substances with new antibiotic properties, and finally in the context of technical applications such as an...
This study tests the hypotheses that the birefringent calcite and stereom structure of the brittlestar (Ophiuroidea, Echinodermata) endoskeleton polarizes light and that certain brittlestars respond to polarized light. The first hypothesis was tested in Ophioderma brevispinum by examining ossicles from freshly killed specimens under polarized light. This analysis revealed that the lateral arm s...
Timing of fission in the starfish Allostichaster capensis (Echinodermata: Asteroidea) in laboratory.
Timing of fission in the fissiparous starfish Allostichaster capensis under laboratory conditions is described. A. capensis generally splits across the disc along the fission plane during the spring, and then each half regenerates the missing arms during the rest of the year. The fission process can last eight hours. The healing process starts immediately after fission. A. capensis has impressi...
The deuterostome phyla include Echinodermata, Hemichordata, and Chordata. Chordata is composed of three subphyla, Vertebrata, Cephalochordata (Branchiostoma), and Urochordata (Tunicata). Careful analysis of a new 18S rDNA data set indicates that deuterostomes are composed of two major clades: chordates and echinoderms + hemichordates. This analysis strongly supports the monophyly of each of the...
Ambulacraria, comprising Hemichordata and Echinodermata, is closely related to Chordata, making it integral to understanding chordate origins and polarizing chordate molecular and morphological characters. Unfortunately, relationships within Hemichordata and Echinodermata have remained unresolved, compromising our ability to extrapolate findings from the most closely related molecular and devel...
Synopsis Free-swimming planktonic larvae are a key stage in the development of many marine phyla, and studies these organisms have contributed to our understanding major genetic evolutionary processes. Although transitory, often attain remarkable degree tissue complexity, with well-defined musculature nervous systems. Among best studied belonging phylum Echinodermata, but work largely focused o...
A new fissiparous asterinid seastar Aquilonastra chantalae sp. nov. is described from Europa Island, one of the Scattered Islands (Les îles Éparses) in the Mozambique Channel. It is compared with the fissiparous asterinid Aquilonastra conandae O'Loughlin & Rowe from the Mascarene Islands. A table of distinguishing diagnostic characters is provided. The asterinid Aquilonastra richmondi O'Loughli...
Background & Aims: Sea urchin immune responses are directly exposed to potentially pathogenic microorganisms and develop defence responses mainly based on immunocytes and humoral factors contained in the coelomic fluid. In addition, the polyhydroxylated 1, 4-naphthoquinone pigments are found to possess excellent antimicrobial, antialgal and antioxidant activities. The present ...
The sulfated mucopolysaccharide composition of 22 species of invertebrates belonging to the phyla Arthropoda, Mollusca, Annelida, Tunicata, Echinodermata, Coelenterata, and Porifera was analyzed. It is shown that all the species contain variable amounts of one or more types of sulfated mocopolysaccharides, most of which similar to the ones found in vertebrates. It is shown also that each specie...
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