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African clawed frog - Wikipedia, the free encyclopedia The African clawed frog (Xenopus laevis, also known as platanna) is a species of South African aquatic frog of the genus Xenopus. laevis is not blessed with the short generation time and genetic simplicity generally desired in genetic model organisms, it is an important model organism in developmental biology. laevis and a global decline in frog populations due to the spread of chytridiomycosis [1]. en.wikipedia.org /wiki/Xenopus_laevis   (538 words)

Xenopus - Wikipedia, the free encyclopedia Xenopus are a clawed, carnivorous genus of African frog. Xenopus are a popular model system for gene and protein expression and knockdown studies. While Xenopus laevis is the most commonly used species for developmental biology studies, genetic studies can be complicated by their pseudotetraploid genome. en.wikipedia.org /wiki/Xenopus   (244 words)

Digimorph - Xenopus laevis (African clawed frog) Xenopus is highly aquatic and bears several adaptations for this environment, including a dorsoventrally flattened body, dorsally directed eyes, the presence of a lateral line system throughout life, and large muscular hindlimbs. Xenopus is a member of the Pipidae, a taxon defined as the most recent common ancestor of Xenopus, Silurana, Hymenochirus, Pseudhymenochirus, and Pipa, and all of its descendents (Ford and Cannatella, 1993). The usefulness of Xenopus as a model organism is due largely to the ease of maintaining breeding populations in the laboratory (Cannatella and De Sa, 1993). digimorph.org /specimens/Xenopus_laevis   (411 words)

THE NATURAL AND UNNATURAL HISTORIES OF XENOPUS LAEVIS The most extensively examined Xenopus is laevis; all of the laboratory studies on this species use the sub-species laevis laevis from South Africa. However, the prevalence of laevis (whose common name is platanna or platie on account of being flattened) and its uncharismatic appearance somewhat diminished its potential as an exotic. Using Xenopus borealis Tony Blackler established that the decision of a primordial germ cell to become an egg or a sperm cell is determined by the genetic sex of the gonad into which it migrates and not by its intrinsic genetic makeup (zz, male or zw, female). www.columbia.edu /cu/biology/faculty/kelley/webessay/histories.html   (1509 words)

Feral Xenopus laevis in South Wales laevis to alien environments are associated with its use in human pregnancy diagnosis, as a laboratory animal, and in the pet trade in the 1950s and 1960s. laevis in an impoundment in Transkei (Schoonbee, Prinsloo and Nxiweni, 1992) and from a stream in California (McCoid and Fritts, 1980). In a recent review of diet in Xenopus, it was considered to be unlikely that the large amount of terrestrial prey previously reported in stomach contents originates solely from invertebrates which have fallen or been swept from overhanging vegetation into the water. www.botany.uwc.ac.za /presents/FocusOn/frogs/feral.htm   (743 words)

Xenopus laevis Embryo, Dorsalization Xenopus eggs contain transcripts encoding components of the Wnt pathway.We have previously discussed the accumulation and localization of Xwnt-11 transcripts during oogenesis. Merriam, J.M., Rubenstein, A.B. and Klymkowsky, M.W. Cytoplasmically anchored plakoglobin induces a WNT-like phenotype in Xenopus. Miller, J.R., Rowning, B.A., Larabell, C.A., Yang-Snyder, J.A., Bates, R.L., and Moon, R.T. Establishment of the dorsal-ventral axis in Xenopus embryos coincedes with the dorsal enrichment of dishevelled that is dependent on cortical rotation. www.ucalgary.ca /UofC/eduweb/virtualembryo/dorsal.html   (1260 words)

THE AFRICAN CLAWED FROG (Xenopus laevis) - HerpStation - Reptiles, Amphibians, Herps, Herptiles - A Division of ... Introduction Although the African Clawed Frog, Xenopus laevis, is commonly seen in captivity, little authoritative information on its husbandry and breeding is available to the lay public. The term "Xenopus" is Latin for "peculiar foot," an apt description of the enormous webbed, five-toed, three-clawed rear feet typical of the group. The Xenopus laevis was the first vertebrate to be successfully cloned and has traveled aboard the Space Shuttle on several occasions. www.petstation.com /clfrog.html   (2502 words)

Terry Gampper's Xenopus Page As the African continent moved northward, the range of Xenopus was restricted because hot, arid conditions developed in the north forcing the frogs to move south of the Sahara. Under normal circumstances, Xenopus frogs never leave the water, although they have occasionally they have been known to migrate if their home pond dries up. Xenopus are multicolored, with their backs in various shades of olive gray with large gray blotches. members.aol.com /__121b_oIqrsZfY/DfNHydwc1gT6QgLKQJ2hUjimftLeovZc9c=   (1002 words)

Ecology of Xenopus laevis by John Measey   (Site not responding. Last check: 2007-10-21) laevis as an assay for luteinising hormone, and thus pregnancy testing, led to mass movement of the humble Platanna to laboratories pan-globally. laevis as the laboratory amphibian in schools, universities, pregnancy clinics, medical research establishments, and as pets, has meant that this animal is familiar to biologists the world over, and has even established feral populations. Little has been added on the subject of feeding and diet in Xenopus since the observations made by Leslie (1890), who wrote; "Unlike other frogs, it feeds in the water, on insects, small fishes, or even young and larvae of its own kind, and is apparently unable to feed out of that element. www.botany.uwc.ac.za /presents/FocusOn/frogs/XENOPU.htm   (462 words)

research A main goal of this research is to determine the developmental pattern of ion channel expression in hair cells and the sensory ganglion cells of the inner ear, with the ultimate goal of understanding the regulation of ion channels in developing auditory and vestibular organs. Xenopus tropicalis and Xenopus laevis are being used as experimental models. The effect of hypergravity exposure during the development of Xenopus tropicalis and Xenopus laevis is being assessed by examining morphogenesis, cell structure, and gene expression. taipan.nmsu.edu /neurolab/research/research.html   (1190 words)

NAS - Species FactSheet   (Site not responding. Last check: 2007-10-21) Identification: Xenopus laevis is a flattened frog with a small head and a SVL (snout-vent length) of 50-over 130 mm (2-over 5 in) (Passmore and Carruthers, 1995; Kobel et al., 1996; Channing, 2001; Stebbins, 2003). Xenopus laevis is a primarily aquatic, highly adaptable frog that can inhabit almost any body of water, natural or man-made, and tolerates sewage and relatively saline (up to 40%) waters (Passmore and Carruthers, 1995; Tinsley et al., 1996; Lafferty and Page, 1997; Channing, 2001). Xenopus laevis can survive starvation conditions for at least 12 months and can rapidly regain lost weight when food is once again available (Tinsley et al., 1996). nas.er.usgs.gov /queries/FactSheet.asp?speciesID=67   (2931 words)

XPak3 promotes cell cycle withdrawal during primary neurogenesis in Xenopus laevis   (Site not responding. Last check: 2007-10-21) This cascade of reactions, referred to as the proneural pathway, is antagonized by the neurogenic pathway that is governed by Delta/Notch signalling in a process known as lateral inhibition (Coffman et al., 1990; Chitnis et al., 1995; Chitnis and Kintner, 1996; Lamar et al., 2001). In Xenopus, spatial and temporal patterns of cell cycle activities during early embryogenesis define the neural plate as an area of increased proliferative activity as compared with the non-neural ectoderm (Saka and Smith, 2001), raising the question as to how the developing neurons withdraw from the cell cycle in order to sustain neuronal differentiation. Xenopus albino embryos were injected into one blastomere at the two-cell stage with (A) 10 pg of XPak3-myr RNA, (B) 2.5 pmol of XPak3-MO and (C) 2.5 pmol of XPak3-MO/12.5 pg XPak3-myr RNA, all with LacZ RNA as tracer. www.nature.com /cgi-taf/dynapage.taf?file=/emboj/journal/v21/n23/full/7594860a.html   (7291 words)

RESEARCH - Lab Animals Xenopus Laevis is a gentle animal that lives entirely in fresh water and can repeatedly be induced to lay eggs by simple hormone injection. For decades, biologists have used Xenopus laevis as their model system for research on a wide spectrum of fundamental issues concerning vertebrate development. The chief disadvantages of Xenopus laevis are its long generation time (two years) and its tetraploidy. www2.umdnj.edu /zhlabweb/animals.htm   (261 words)

Environmental Estrogens Alter Early Development in Xenopus laevis   (Site not responding. Last check: 2007-10-21) We exposed Xenopus laevis embryos at early gastrula to the commonly encountered environmental estrogens nonylphenol, octylphenol, and methoxychlor, the antiandrogen, p,p´-DDE, or the synthetic androgen, 17 In particular, the laboratory frog Xenopus laevis provides an excellent model system to assess the effects of early exposure to environmental toxicants because of its ability to generate embryos on a daily basis and because the molecular and organismal development of this vertebrate has been described extensively (for review, see Mayor et al. Snail-related transcriptional repressors are required in Xenopus for both the induction of the neural crest and its subsequent migration. ehp.niehs.nih.gov /members/2003/5500/5500.html   (6946 words)

Xenopus laevis development   (Site not responding. Last check: 2007-10-21) Xenopus laevis is widely used as a model for early vertebrate development. The early Xenopus embryo forms two distinct halves, the pigmented animal pole and the yolky vegetal pole. Gastrulation in Xenopus involves radical cell movement (by a number of mechanisms) by the blastula-stage embryo. template.bio.warwick.ac.uk /staff/rold/background.htm   (743 words)

Introduction to X. trop project The pipid frog Xenopus laevis has been among the most productive model systems for vertebrate experimental embryology, due to the large size, external development, robustness, and ease of molecular and surgical manipulation of its embryos. One reason amphibian embryos are superb for embryological manipulations is that each cell contains its own power source- a yolk supply- enhancing its ability to withstand the rigors of transplantation or to continue to differentiate in an explant or as an individual cell in simple salt solutions. This greatly complicates creating mutants (since it may be necessary to inactivate four copies of a gene) and analyzing gene regulation (since it may be difficult to distinguish genomic clones of pseudogenes from those of active loci). faculty.virginia.edu /xtropicalis/overview/intro.html   (624 words)

Developmental Staging in Xenopus laevis Xenopus is at once elegantly simple and infinitely complex--I found it a wonder to study. Meanwhile, in developmental biology I was struggling with the staging of Xenopus tadpoles. The South African clawed frog Xenopus laevis is widely used as a model organism in developmental biology because its transformation from zygote to tadpole can be easily observed in the laboratory. www.bio.davidson.edu /people/balom/StagingTable/Preface.html   (540 words)

JGI X. tropicalis v3.0 Home In the former, Xenopus laevis has led the way in identifying the mechanisms of early fate decisions, patterning of the basic vertebrate body plan, and early organogenesis. In fact, Xenopus has become a major vertebrate model for the cellular and developmental biology research that is supported by most of the Institutes of the NIH. In addition, a Xenopus tropicalis genome project advisory board was set up to insure an accurate and timely exchange of information between the JGI and the research community. genome.jgi-psf.org /Xentr3/Xentr3.home.html   (411 words)

An endogenous monocarboxylate transport in Xenopus laevis oocytes -- Tosco et al. 278 (5): 1190 -- AJP - Regulatory, ... An endogenous monocarboxylate transport in Xenopus laevis oocytes -- Tosco et al. Characterization of the high-affinity monocarboxylate transporter MCT2 in Xenopus laevis oocytes. Dascal, N. The use of Xenopus laevis oocytes for the study of ion channels. ajpregu.physiology.org /cgi/content/full/278/5/R1190   (3587 words)

Xenopus laevis The Xenopus laevis Gene Index (XGI) from The Institute of Genomic Research (TIGR) integrates research data from international EST sequencing and gene research projects. Axeldb is a database that stores and integrates gene expression patterns and DNA sequences identified in an ongoing large-scale in situ hybridization study in Xenopus laevis embryos. The laboratory uses Xenopus laevis tadpoles to investigate "the neural mechanisms underlying the development and intrinsic modulation of locomotion." Information is given on the lab members, current projects, publications, news, vacancies, and pictures of the tadpoles. bioresearch.ac.uk /browse/mesh/D014982.html   (311 words)

Gamete Interactions in Xenopus laevis: Identification of Sperm Binding Glycoproteins in the Egg Vitelline Envelope -- ... Xenopus laevis frogs were purchased from Nasco Biological Supply Co. (Fort Atkinson, WI). The extracellular matrix of Xenopus laevis eggs: a quick-freeze, deep-etch analysis of its modification at fertilization. Viability and artificial fertilization of Xenopus laevis gametes. www.jcb.org /cgi/content/full/136/5/1099   (7086 words)

Xenopus Express Links A database focussing on gene expression in the frog Xenopus laevis. Guidelines for Egg and Oocyte Harvesting in Xenopus laevis Xenopus oocyte isolation, maturation, enucleation, fractionation and injection. www.xenopus.com /links.htm   (1107 words)

Introduced Species Summary Project - Xenopus laevis The genus Xenopus is the only frog with clawed toes. Within this genus, laevis is the only species that exceeds 100 mm in length, with femals adults reaching 110-130 mm and male adults generally 10-30% smaller. Schoonbee, H.J., J.F. Prinsloo, J.G. Nxweni, 1992, Observations on the Feeding Habits of Larvae, Juvenile, and Adult Stages of the African clawed frog, Xenopus laevis, in impounds in Transkei, Water SA, 18(4): 227-236. www.columbia.edu /itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/xenopus_laevis.htm   (1444 words)

:: X. Tropicalis :: home The pipid frog Xenopus (Silurana) tropicalis presents the opportunity to combine sophisticated embryological methods with developmental genetics in a vertebrate system. Closely resembling those of its well-characterized cousin, Xenopus laevis, X. tropicalis embryos are readily manipulated by techniques ranging from explant assays to transgenesis, and can be evaluated with most X. laevis molecular probes. We are optimizing husbandry regimes to further shorten generation time, adapting X. laevis protocols, and assembling a set of genetic research tools including chemical and insertional mutagenesis, gene traps, stable transgenic reporter lines, inducible gene expression systems, and genetic and physical maps of the X. tropicalis genome. faculty.virginia.edu /xtropicalis   (156 words)

Trans-NIH Xenopus Initiative   (Site not responding. Last check: 2007-10-21) This Web Site has been developed to help keep you aware of NIH's progress and plans regarding support of the genomic and genetic needs for Xenopus research. An initial series of recommendations of needs for Xenopus research was devised by participants of the NIH's Non-Mammalian Model Workshop in February 1999. These resources will enable researchers to enhance the advantages of Xenopus to provide critical breakthroughs in our understanding of embryonic development, organogenesis, oncogenesis, and cell biological processes. www.nih.gov /science/models/xenopus   (114 words)

Xenopus laevis Stromal Cell-Derived Factor 1: Conservation of Structure and Function During Vertebrate Development -- ... Xenopus laevis Stromal Cell-Derived Factor 1: Conservation of Structure and Function During Vertebrate Development -- Braun et al. A, Digoxigenin-labeled xSDF-1 antisense RNA was prepared and hybridized to Xenopus embryos (stages 21–23, 32–34, and 39–40). Characterization of a Xenopus laevis CXC chemokine receptor 4: implications for hematopoietic cell development in the vertebrate embryo. www.jimmunol.org /cgi/content/full/168/5/2340   (5464 words)

Selecting karyophilic DNA cis elements in Xenopus laevis oocytes; a new approach   (Site not responding. Last check: 2007-10-21) ABSTRACT The intracellular localisation and mobility of exogenous DNA introduced into Xenopus laevis oocytes is largely unknown. In this paper, we report a new technique to investigate the cytoplasmic/nuclear transport of a random pool of linear, double-stranded, oligomeric DNA of 147 bp in length. A new PCR-based methodology was established to reliably detect exogenous DNA in subcellular and total extracts prepared from Xenopus laevis oocytes. www.ijdb.ehu.es /abstract.0203/a309.html   (189 words)

The Sanger Institute: Xenopus tropicalis We are pleased to announce the first Ensembl site for Xenopus tropicalis based on the assembly V3.0 by the JGI. Xenopus laevis has been favoured by biologists to investigate the mechanism of vertebrate embryonic development. Xenopus tropicalis, which is the only diploid species in the Xenopus genus and therefore better suited for genetic approaches. www.sanger.ac.uk /Projects/X_tropicalis   (229 words)

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