Results 251 to 260 of about 1,405,896 (309)
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Biological Reviews, 1951
Summaryi. The head of the sea‐urchin spermatozoon is pear‐shaped and axially symmetrical. The sub‐microscopic morphology of the middle piece has not been investigated, but the tail, which terminates in an axial fibre, probably contains spiral or coiled structures, as in mammalian spermatozoa.2.
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Summaryi. The head of the sea‐urchin spermatozoon is pear‐shaped and axially symmetrical. The sub‐microscopic morphology of the middle piece has not been investigated, but the tail, which terminates in an axial fibre, probably contains spiral or coiled structures, as in mammalian spermatozoa.2.
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Clinical Toxicology, 2005
A 25-year-old female was walking along a shallow tropical reef when she felt a sharp pain in her right great toe. Upon exiting the water, she noted multiple dark spines protruding from the foot.
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A 25-year-old female was walking along a shallow tropical reef when she felt a sharp pain in her right great toe. Upon exiting the water, she noted multiple dark spines protruding from the foot.
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2004
Publisher Summary The chapter describes the structures and functions of sea urchin spermatozoa. Methods for the isolation of different parts of the sea urchin sperm are discussed. Sea urchin sperm are specialized for five functions: (1) oxidative phosphorylation to produce ATP, (2) flagellar motility, (3) the acrosome reaction, (4) binding to the egg,
Victor D, Vacquier, Noritaka, Hirohashi
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Publisher Summary The chapter describes the structures and functions of sea urchin spermatozoa. Methods for the isolation of different parts of the sea urchin sperm are discussed. Sea urchin sperm are specialized for five functions: (1) oxidative phosphorylation to produce ATP, (2) flagellar motility, (3) the acrosome reaction, (4) binding to the egg,
Victor D, Vacquier, Noritaka, Hirohashi
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Relationships among predatory fish, sea urchins and barrens in Mediterranean rocky reefs across a latitudinal gradient [PDF]
Marine Environmental Research, 2007 Previous studies conducted on a local scale emphasised the potential of trophic cascades in Mediterranean rocky reefs (involving predatory fish, sea urchins and macroalgae) in affecting the transition between benthic communities dominated by erected ...
Paolo Guidetti, J Dulčić
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Sea urchin DNA methyltransferases
Cell Biophysics, 1989DNA methyltransferase activities have been partially purified from unfertilized eggs and blastula nuclei of sea urchin embryos. Comparative studies, using different DNAs as substrates, show that the two preparations are most active on hemimethylated and single-strand DNA, but they methylate, though at a lower rate, also on double-strand DNA.
Tosi L +5 more
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2016
In the sea urchin morphogenesis follows extensive molecular specification. The specification controls the many morphogenetic events and these, in turn, precede patterning steps that establish the larval body plan. To understand how the embryo is built it was necessary to understand those series of molecular steps.
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In the sea urchin morphogenesis follows extensive molecular specification. The specification controls the many morphogenetic events and these, in turn, precede patterning steps that establish the larval body plan. To understand how the embryo is built it was necessary to understand those series of molecular steps.
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Apoptosis in Sea Urchin Embryos
Biochemical and Biophysical Research Communications, 1997It is demonstrated by DNA electrophoresis analysis, morphological observations and TdT in situ reaction, that Paracentrotus embryos if treated with TPA plus heat undergo an apoptotic reaction. Indication is also obtained that non treated embryos undergo spontaneous apoptosis at the early pluteus stage, especially in the districts of arms and intestine.
M C, Roccheri +7 more
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Activation of Sea Urchin Gametes
Annual Review of Cell Biology, 1986CONTENTS INTRODUCTION .••••••••........ 1 SPERMATOZOA . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . ...... . . . . . . . . . . . .. . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . 3 Activation of Motility and Respiration... . . . . . . . . . . . . . . . . . . . . .
J S, Trimmer, V D, Vacquier
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Southern Medical Journal, 1977
Injuries from sea urchins result from penetration of the calcareous spines into the skin. Local pain of several days' duration is the most common symptom, but systemic reaction from toxins found in certain species can occur. There is no uniformly accepted successful treatment other than cleansing the wound.
HOWARD P. BADEN +2 more
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Injuries from sea urchins result from penetration of the calcareous spines into the skin. Local pain of several days' duration is the most common symptom, but systemic reaction from toxins found in certain species can occur. There is no uniformly accepted successful treatment other than cleansing the wound.
HOWARD P. BADEN +2 more
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The chromatin of sea urchin sperm
Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression, 1987Digestion of sea urchin sperm nuclei with micrococcal nuclease yields nucleosomal monomer fragments of 151 and 164 base pairs. Prior trypsin treatment of the sperm chromatin does not alter the size of these monomer DNA fragments despite the fact that the H1 histone is reduced to a limit globular peptide of about 83 residues. Heterologous reconstitution
P, Puigdomenech +5 more
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