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Find video protocols related to scientific articles indexed in Pubmed.
New insights on ctenophore neural anatomy: immunofluorescence study in Pleurobrachia pileus (Müller, 1776).
J. Exp. Zool. B Mol. Dev. Evol.
PUBLISHED: 04-05-2011
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Ctenophores are non-bilaterian animals sharing with cnidarians and bilaterians the presence of sensory receptors, nerve cells, and synapses, absent in placozoans and sponges. Although recent immunofluorescence studies have renewed our knowledge of cnidarian neuro-anatomy, ctenophores have been much less investigated despite their importance to understanding the origin and early evolution of the nervous system. In this study, the neuro-anatomy of the ctenophore Pleurobrachia pileus (Müller, 1776) was explored by whole-mount fluorescent antibody staining using antibodies against tyrosylated -tubulin, FMRFamide, and vasopressin. We describe the morphology of nerve nets and their local specializations, and the organization of the aboral neuro-sensory complex comprising the apical organ and polar fields. Two distinct nerve nets are distinguished: a mesogleal nerve net, loosely organized throughout body mesoglea, and a much more compact “nerve net” with polygonal meshes in the ectodermal epithelium. The latter is organized as a plexus of short nerve cords. This epithelial nervous system contains distinct sub-populations of dispersed FMRFamide and vasopressin immunoreactive nerve cells. In the aboral neuro-sensory complex, our most significant observations include specialized nerve nets underlying the apical organ and polar fields, a tangential bundle of actin-rich fibers (interpreted as a muscle) within the polar fields, and distinct groups of neurons labeled by anti-FMRFamide and anti-vasopressin antibodies, within the apical organ floor. These results are discussed in a comparative perspective.
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Multiple Sox genes are expressed in stem cells or in differentiating neuro-sensory cells in the hydrozoan Clytia hemisphaerica.
Evodevo
PUBLISHED: 03-02-2011
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The Sox genes are important regulators of animal development belonging to the HMG domain-containing class of transcription factors. Studies in bilaterian models have notably highlighted their pivotal role in controlling progression along cell lineages, various Sox family members being involved at one side or the other of the critical balance between self-renewing stem cells/proliferating progenitors, and cells undergoing differentiation.
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Somatic stem cells express Piwi and Vasa genes in an adult ctenophore: ancient association of "germline genes" with stemness.
Dev. Biol.
PUBLISHED: 07-31-2010
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Stem cells are essential for animal development and adult tissue homeostasis, and the quest for an ancestral gene fingerprint of stemness is a major challenge for evolutionary developmental biology. Recent studies have indicated that a series of genes, including the transposon silencer Piwi and the translational activator Vasa, specifically involved in germline determination and maintenance in classical bilaterian models (e.g., vertebrates, fly, nematode), are more generally expressed in adult multipotent stem cells in other animals like flatworms and hydras. Since the progeny of these multipotent stem cells includes both somatic and germinal derivatives, it remains unclear whether Vasa, Piwi, and associated genes like Bruno and PL10 were ancestrally linked to stemness, or to germinal potential. We have investigated the expression of Vasa, two Piwi paralogues, Bruno and PL10 in Pleurobrachia pileus, a member of the early-diverging phylum Ctenophora, the probable sister group of cnidarians. These genes were all expressed in the male and female germlines, and with the exception of one of the Piwi paralogues, they showed similar expression patterns within somatic territories (tentacle root, comb rows, aboral sensory complex). Cytological observations and EdU DNA-labelling and long-term retention experiments revealed concentrations of stem cells closely matching these gene expression areas. These stem cell pools are spatially restricted, and each specialised in the production of particular types of somatic cells. These data unveil important aspects of cell renewal within the ctenophore body and suggest that Piwi, Vasa, Bruno, and PL10 belong to a gene network ancestrally acting in two distinct contexts: (i) the germline and (ii) stem cells, whatever the nature of their progeny.
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New tricks with old genes: the genetic bases of novel cnidarian traits.
Trends Genet.
PUBLISHED: 01-07-2010
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Recent thought on genome evolution has focused on the creation of new genes and changes in regulatory mechanisms while ignoring the role of selective gene loss in shaping genomes. Using data from two cnidarians, the jellyfish Clytia and the coral Acropora, we examined the relative significance of new taxonomically restricted genes and selectively retained ancestral genes in enabling the evolution of novel traits. Consistent with its more complex life-cycle, the proportion of novel genes identified in Clytia was higher than that in the polyp only cnidarians Nematostella and Hydra, but each of these cnidarians has retained a proportion of ancestral genes not present in the other two. The ubiquity and near-stochastic nature of gene loss can explain the discord between patterns of gene distribution and taxonomy.
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Phylogenomics revives traditional views on deep animal relationships.
Curr. Biol.
PUBLISHED: 02-22-2009
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The origin of many of the defining features of animal body plans, such as symmetry, nervous system, and the mesoderm, remains shrouded in mystery because of major uncertainty regarding the emergence order of the early branching taxa: the sponge groups, ctenophores, placozoans, cnidarians, and bilaterians. The "phylogenomic" approach [1] has recently provided a robust picture for intrabilaterian relationships [2, 3] but not yet for more early branching metazoan clades. We have assembled a comprehensive 128 gene data set including newly generated sequence data from ctenophores, cnidarians, and all four main sponge groups. The resulting phylogeny yields two significant conclusions reviving old views that have been challenged in the molecular era: (1) that the sponges (Porifera) are monophyletic and not paraphyletic as repeatedly proposed [4-9], thus undermining the idea that ancestral metazoans had a sponge-like body plan; (2) that the most likely position for the ctenophores is together with the cnidarians in a "coelenterate" clade. The Porifera and the Placozoa branch basally with respect to a moderately supported "eumetazoan" clade containing the three taxa with nervous system and muscle cells (Cnidaria, Ctenophora, and Bilateria). This new phylogeny provides a stimulating framework for exploring the important changes that shaped the body plans of the early diverging phyla.
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Are Hox genes ancestrally involved in axial patterning? Evidence from the hydrozoan Clytia hemisphaerica (Cnidaria).
PLoS ONE
PUBLISHED: 01-21-2009
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The early evolution and diversification of Hox-related genes in eumetazoans has been the subject of conflicting hypotheses concerning the evolutionary conservation of their role in axial patterning and the pre-bilaterian origin of the Hox and ParaHox clusters. The diversification of Hox/ParaHox genes clearly predates the origin of bilaterians. However, the existence of a "Hox code" predating the cnidarian-bilaterian ancestor and supporting the deep homology of axes is more controversial. This assumption was mainly based on the interpretation of Hox expression data from the sea anemone, but growing evidence from other cnidarian taxa puts into question this hypothesis.
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Independent specialisation of myosin II paralogues in muscle vs. non-muscle functions during early animal evolution: a ctenophore perspective.
BMC Evol. Biol.
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Myosin II (or Myosin Heavy Chain II, MHCII) is a family of molecular motors involved in the contractile activity of animal muscle cells but also in various other cellular processes in non-muscle cells. Previous phylogenetic analyses of bilaterian MHCII genes identified two main clades associated respectively with smooth/non-muscle cells (MHCIIa) and striated muscle cells (MHCIIb). Muscle cells are generally thought to have originated only once in ancient animal history, and decisive insights about their early evolution are expected to come from expression studies of Myosin II genes in the two non-bilaterian phyla that possess muscles, the Cnidaria and Ctenophora.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.