• Overview
  • Corals and Coral Reefs | Smithsonian Ocean Portal
  • Mars can wait. Oceans can't - CNN

Echinoderm: Echinoderm, any of a variety of invertebrate marine animals belonging to the phylum Echinodermata, characterized by a hard, spiny covering or skin.

Glossary - PBS: Public Broadcasting Service

Reproductive Technology in Farm Animals: New Facets …

Students will begin this unit by exploring heredity at the organismal and cellular levels
Photo provided by Flickr
Adult L. variegatus were collected from wild populations at approximately the same time as cultured urchins were analyzed. The adult urchins were spawned, a fertilization test was performed, and gametes from one male and one female from the wild were fertilized. Again, there was no noticeable difference in the fertilization efficiency of this feed treatment compared to the two treatments described previously. Various stages of embryological and larval development were collected as described previously. Homogenates of embryos and larvae from both cultured and wild sea urchins were stored at −30°C.

WordPress VIP Alternative - RebelMouse

Corals are related to sea anemones, and they all share the same simple structure, the polyp
Photo provided by Flickr
At week 12, lab-cultured sea urchins fed the lettuce and carrot diet or the formulated feed were spawned as described previously. Fertilization tests for each diet treatment, as described previously, were performed to ensure gametes were viable. There were no noticeable differences in the fertilization efficiencies between diet treatment groups. For each diet treatment, gametes of 3+ females and 3+ males were pooled and fertilized. Various stages of embryological and larval development (1.5, 3, 24, 48, 96, and 192 h post-fertilization) were collected as described previously. Embryos from each diet treatment were not appreciably different in size; however, larvae collected at later developmental stages exhibited slight but noticeable differences in arm length.


Beyond the benchtop and the benthos: Dataset …

Fulltext - Reproductive Technology in Farm Animals: New Facets and Findings: A Review
Photo provided by Flickr
Sea urchins have served as experimental models for more than 100years. Many species produce tremendous quantities (millions tobillions; Plate XV) of large, clear eggs that lack externalcoatings. An early example of their utility was Otto Warburg'sdemonstration in 1908 of the increase in oxygen consumption thatoccurs following fertilization, despite the relative insensitivityof his methods.

Sea Urchin Life History Strategies - ScienceDirect
Photo provided by Flickr
More than 50 years ago a spike in intracellular calciumconcentration was identified in eggs followingfertilization. This calcium signal triggers formation of a clearproteinaceous fertilization envelope that surrounds the entire egg,and by preventing sperm from reaching the egg membrane, acts as amechanical block to polyspermy. The calcium signal also contributesto the signal to activate protein and DNA (deoxyribonucleic acid)synthesis at the onset of development. Curiously, the calciumsignal occurs as a wave that begins at the site of sperm-egg fusionand sweeps across the entire egg in approximately 30 seconds (PlateXVI). Such waves, which can be repetitive, occur in many differentkinds of cells in response to a wide variety of stimuli. The natureof the waves has been elucidated by the discovery that they dependon chemical intracellular messengers, some of which were onlyrecently identified in an exciting series of investigations usingsea urchin eggs (Lee, 1997).

Glossary – PBS: Public Broadcasting Service

The cell cycle is the orderly sequence of events in which a cellfirst reproduces its genetic material and then divides. In the lifeof an organism, cell division begins following the fertilization ofthe egg, defines the early growth and differentiation of theembryo, and continues throughout adulthood, especially in tissueslike blood and intestinal mucosa. The cell cycle is closelyregulated by a group of proteins, the cyclins (Pines, 1996), whichwere originally identified in sea urchins (Evans et al., 1983). Thekey features of sea urchin eggs that made this discovery possibleare their abundance and the synchronous division of cells afterfertilization. Researchers radiolabeled newly fertilized eggs totag proteins synthesized during the first few cell divisions. Theyfound that while most proteins accumulate through succeeding cellcycles, one protein, cyclin, is remarkable in that it issynthesized and destroyed once per cell cycle, appearing anddisappearing periodically as the cell divides.

Read chapter 5 Marine Organisms as Models for Biomedical Research: ..

Studies using marine organisms have had a major influence onbiomedical research (Sargent, 1987). This chapter highlights someof the best recognized marine models and elaborates the reasons fortheir success. However, the first question one might askis—why marine organisms? At higher taxonomic levels, mostbiological diversity is found either primarily or exclusively inthe ocean. Of 33 modern phyla, only 11 are found in terrestrialhabitats while 28 occur in marine habitats. Hence the diversity oflife in the sea offers more possibilities for the discovery oforganisms for use as models to explore various biologicalprocesses. In several of the examples described in this chapter,specific adaptations to the marine environment have been valuablein studying analogous physiological processes in humans. Ofparticular interest are several marine taxa that share a commonorigin with mammals. This group, the deuterostomes, includesvertebrates (and other chordates), echinoderms (e.g., sea urchinsand sea stars) and tunicates (e.g., sea squirts). Echinodermsappeared early in the fossil record and are the most distantdeuterostome relatives of humans. Studies on the differences andsimilarities of these groups offer insights into the evolution ofvertebrates and mammals. Also, many of these organisms havespecialized features that have enabled researchers to elucidatecomplex processes that would be more difficult to study in mammals.A number of examples are listed in Table 5-1, of which some aredescribed in more detail in this chapter.

Read chapter 5 Marine Organisms as Models for Biomedical ..

Adult L. variegatus sea urchins were collected from St. Joseph Bay, Florida in May of 2006 and transported to the University of Alabama at Birmingham (UAB). Individuals were held in recirculating seawater systems containing synthetic seawater (Instant Ocean, 32ppt; 22–24°C) and fed a formulated feed () until analysis. Adult sea urchins were spawned by injection of approximately 1 mL of 0.1 M ACh. Gametes were collected by inverting females over a beaker while sperm was collected dry by removing expressed sperm by pipette. Fertilization tests were performed by obtaining a sample of eggs and fertilizing with a sample of diluted sperm on a microscope slide. Eggs were fertilized with diluted sperm to reduce the possibility for polyspermy. After fertilization, zygotes were placed in a shallow glass fingerbowl in synthetic seawater (32 ± 1 ppt). After the first cell divisions were complete, embryos were placed into a larger volume of aerated synthetic seawater and were fed twice daily combined mixtures of the algae Dunaliella tertiolecta, Isochrysis galbana, and Rhodomonas salina (obtained from the University of Texas, Port Aransas, TX) to apparent satiation (stomachs were observed to be full).