Sponges Anatomy of a Sponge
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Divergence of Ectodermal and Mesodermal Gene Regulatory Network Linkages in Early Development of Sea Urchins
Divergence of ectodermal and mesodermal gene regulatory network linkages in early development of sea urchins Eric M. Erkenbracka,1,2 aDivision of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125 Edited by Neil H. Shubin, The University of Chicago, Chicago, IL, and approved October 5, 2016 (received for review August 3, 2016) Developmental gene regulatory networks (GRNs) are assemblages of to study in sea urchins, whose lineages have undergone multiple gene regulatory interactions that direct ontogeny of animal body changes in life history strategies (8). Importantly, an excellent fossil plans. Studies of GRNs operating in the early development of record affords dating of evolutionary events (9), which has established euechinoid sea urchins have revealed that little appreciable change has that the sister subclasses of sea urchins—cidaroids and euechinoids— occurred since their divergence ∼90 million years ago (mya). These diverged at least 268 million years ago (mya) (10). Differences in observations suggest that strong conservation of GRN architecture the timing of developmental events in embryogenesis of cida- was maintained in early development of the sea urchin lineage. Test- roids and euechinoids have long been a topic of interest, but ing whether this holds for all sea urchins necessitates comparative have become the subject of molecular research only recently analyses of echinoid taxa that diverged deeper in geological time. (11–18). Recent studies highlighted extensive divergence of skeletogenic me- Research on the early development of the euechinoid purple soderm specification in the sister clade of euechinoids, the cidaroids, sea urchin Strongylocentrotus purpuratus (Sp) has brought into suggesting that comparative analyses of cidaroid GRN architecture high resolution the players and molecular logic directing devel- may confer a greater understanding of the evolutionary dynamics of opmental GRNs that specify Sp’s early embryonic domains developmental GRNs. -
Animal Origins and the Evolution of Body Plans 621
Animal Origins and the Evolution 32 of Body Plans In 1822, nearly forty years before Darwin wrote The Origin of Species, a French naturalist, Étienne Geoffroy Saint-Hilaire, was examining a lob- ster. He noticed that when he turned the lobster upside down and viewed it with its ventral surface up, its central nervous system was located above its digestive tract, which in turn was located above its heart—the same relative positions these systems have in mammals when viewed dorsally. His observations led Geoffroy to conclude that the differences between arthropods (such as lobsters) and vertebrates (such as mammals) could be explained if the embryos of one of those groups were inverted during development. Geoffroy’s suggestion was regarded as preposterous at the time and was largely dismissed until recently. However, the discovery of two genes that influence a sys- tem of extracellular signals involved in development has lent new support to Geof- froy’s seemingly outrageous hypothesis. Genes that Control Development A A vertebrate gene called chordin helps to establish cells on one side of the embryo human and a lobster carry similar genes that control the development of the body as dorsal and on the other as ventral. A probably homologous gene in fruit flies, called axis, but these genes position their body sog, acts in a similar manner, but has the opposite effect. Fly cells where sog is active systems inversely. A lobster’s nervous sys- become ventral, whereas vertebrate cells where chordin is active become dorsal. How- tem runs up its ventral (belly) surface, whereas a vertebrate’s runs down its dorsal ever, when sog mRNA is injected into an embryo (back) surface. -
Animal Form & Function
Animals Animal Form & Function By far, most diversity of bauplane (body forms). And most variations within bauplane. Animals are Animated “ANIMAL” ≠ MAMMAL — Fascinating Behaviors Animal Cells • Eukaryotic • No cell wall No plastids No central vacuole • Multicellular: – extensive specialization & differentiation – unique cell-cell junctions Heyer 1 Animals Animals Blastulation & Gastrulation • Motile • Early embryonic development in animals 3 In most animals, cleavage results in the formation of a multicellular stage called a 1 The zygote of an animal • Highly differentiated blastula. The blastula of many animals is a undergoes a succession of mitotic tissues cell divisions called cleavage. hollow ball of cells. Blastocoel • Intercellular junctions Cleavage Cleavage – tissue-specific cadherins 6 The endoderm of the archenteron develops into Eight-cell stage Blastula Cross section Zygote • Extracellular protein the the animal’s of blastula fibers digestive tract. Blastocoel Endoderm – collagen 5 The blind pouch formed by gastrulation, called Ectoderm • Diploid life cycle the archenteron, opens to the outside Gastrula Gastrulation via the blastopore. Blastopore 4 Most animals also undergo gastrulation, a • Blastula/gastrula rearrangement of the embryo in which one end of the embryo folds inward, expands, and eventually fills the embryo blastocoel, producing layers of embryonic tissues: the Figure 32.2 ectoderm (outer layer) and the endoderm (inner layer). Primary embryonic germ layers Primary embryonic germ layers • Diploblastic: two germ -
T-Brain Regulates Archenteron Induction Signal 5207 Range of Amplification
Development 129, 5205-5216 (2002) 5205 Printed in Great Britain © The Company of Biologists Limited 2002 DEV5034 T-brain homologue (HpTb) is involved in the archenteron induction signals of micromere descendant cells in the sea urchin embryo Takuya Fuchikami1, Keiko Mitsunaga-Nakatsubo1, Shonan Amemiya2, Toshiya Hosomi1, Takashi Watanabe1, Daisuke Kurokawa1,*, Miho Kataoka1, Yoshito Harada3, Nori Satoh3, Shinichiro Kusunoki4, Kazuko Takata1, Taishin Shimotori1, Takashi Yamamoto1, Naoaki Sakamoto1, Hiraku Shimada1 and Koji Akasaka1,† 1Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan 2Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan 3Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan 4LSL, Nerima-ku, Tokyo 178-0061, Japan *Present address: Evolutionary Regeneration Biology Group, RIKEN Center for Developmental Biology, Kobe 650-0047, Japan †Author for correspondence (e-mail: [email protected]) Accepted 30 July 2002 SUMMARY Signals from micromere descendants play a crucial role in cells, the initial specification of primary mesenchyme cells, sea urchin development. In this study, we demonstrate that or the specification of endoderm. HpTb expression is these micromere descendants express HpTb, a T-brain controlled by nuclear localization of β-catenin, suggesting homolog of Hemicentrotus pulcherrimus. HpTb is expressed that -
Apoptosis in Amphibian Development
Advances in Bioscience and Biotechnology, 2012, 3, 669-678 ABB http://dx.doi.org/10.4236/abb.2012.326087 Published Online October 2012 (http://www.SciRP.org/journal/abb/) Apoptosis in amphibian development Jean-Marie Exbrayat, Elara N. Moudilou, Lucie Abrouk, Claire Brun Université de Lyon, UMRS 449, Biologie Générale, Université Catholique de Lyon, Reproduction et Développement Comparé, Ecole Pratique des Hautes Etudes, Lyon, France Email: [email protected] Received 13 August 2012; revised 20 September 2012; accepted 28 September 2012 ABSTRACT divide to give the first two blastomeres which continue to divide becoming a morula. An inner cavity, the blasto- Amphibians and more particularly X. laevis are mod- coel, appears in the mass cell of the embryo, becoming a els often used for studying apoptosis during embry- blastula. During this period of cleavage, the size and onic development. Using several methods, searchers shape of embryos do not vary. Before mid blastula tran- determined the localization of programmed cell sition (MBT), zygotic genes do not express excepted deaths (PCD). Several experimental methods also those encoding for proteins implicated in membrane have been used to understand the regulatory mecha- building. Maternal mRNAs previously accumulated in nisms of apoptosis, throughout development, contrib- the oocytes remain present in the cytoplasm of zygote uting to elucidate the general action of several genes and they are distributed into the cytoplasm of blas- and proteins. Apoptosis occurs very early, with a first tomeres during cleavage. These maternal mRNAs encode program under control of maternal genes expressed for proteins which will be implicated in expression of before MBT, in order to eliminate damaged cells be- zygotic genes. -
Mitochondrial Genomes of Two Polydora
www.nature.com/scientificreports OPEN Mitochondrial genomes of two Polydora (Spionidae) species provide further evidence that mitochondrial architecture in the Sedentaria (Annelida) is not conserved Lingtong Ye1*, Tuo Yao1, Jie Lu1, Jingzhe Jiang1 & Changming Bai2 Contrary to the early evidence, which indicated that the mitochondrial architecture in one of the two major annelida clades, Sedentaria, is relatively conserved, a handful of relatively recent studies found evidence that some species exhibit elevated rates of mitochondrial architecture evolution. We sequenced complete mitogenomes belonging to two congeneric shell-boring Spionidae species that cause considerable economic losses in the commercial marine mollusk aquaculture: Polydora brevipalpa and Polydora websteri. The two mitogenomes exhibited very similar architecture. In comparison to other sedentarians, they exhibited some standard features, including all genes encoded on the same strand, uncommon but not unique duplicated trnM gene, as well as a number of unique features. Their comparatively large size (17,673 bp) can be attributed to four non-coding regions larger than 500 bp. We identifed an unusually large (putative) overlap of 14 bases between nad2 and cox1 genes in both species. Importantly, the two species exhibited completely rearranged gene orders in comparison to all other available mitogenomes. Along with Serpulidae and Sabellidae, Polydora is the third identifed sedentarian lineage that exhibits disproportionally elevated rates of mitogenomic architecture rearrangements. Selection analyses indicate that these three lineages also exhibited relaxed purifying selection pressures. Abbreviations NCR Non-coding region PCG Protein-coding gene Metazoan mitochondrial genomes (mitogenomes) usually encode the set of 37 genes, comprising 2 rRNAs, 22 tRNAs, and 13 proteins, encoded on both genomic strands. -
Defining Phyla: Evolutionary Pathways to Metazoan Body Plans
EVOLUTION & DEVELOPMENT 3:6, 432-442 (2001) Defining phyla: evolutionary pathways to metazoan body plans Allen G. Collins^ and James W. Valentine* Museum of Paleontology and Department of Integrative Biology, University of California, Berkeley, CA 94720, USA 'Author for correspondence (email: [email protected]) 'Present address: Section of Ecology, Befiavior, and Evolution, Division of Biology, University of California, San Diego, La Jolla, CA 92093-0116, USA SUMMARY Phyla are defined by two sets of criteria, one pothesis of Nielsen; the clonal hypothesis of Dewel; the set- morphological and the other historical. Molecular evidence aside cell hypothesis of Davidson et al.; and a benthic hy- permits the grouping of animals into clades and suggests that pothesis suggested by the fossil record. It is concluded that a some groups widely recognized as phyla are paraphyletic, benthic radiation of animals could have supplied the ances- while some may be polyphyletic; the phyletic status of crown tral lineages of all but a few phyla, is consistent with molecu- phyla is tabulated. Four recent evolutionary scenarios for the lar evidence, accords well with fossil evidence, and accounts origins of metazoan phyla and of supraphyletic clades are as- for some of the difficulties in phylogenetic analyses of phyla sessed in the light of a molecular phylogeny: the trochaea hy- based on morphological criteria. INTRODUCTION Molecules have provided an important operational ad- vance to addressing questions about the origins of animal Concepts of animal phyla have changed importantly from phyla. Molecular developmental and comparative genomic their origins in the six Linnaean classis and four Cuvieran evidence offer insights into the genetic bases of body plan embranchements. -
Animal Phylum Poster Porifera
Phylum PORIFERA CNIDARIA PLATYHELMINTHES ANNELIDA MOLLUSCA ECHINODERMATA ARTHROPODA CHORDATA Hexactinellida -- glass (siliceous) Anthozoa -- corals and sea Turbellaria -- free-living or symbiotic Polychaetes -- segmented Gastopods -- snails and slugs Asteroidea -- starfish Trilobitomorpha -- tribolites (extinct) Urochordata -- tunicates Groups sponges anemones flatworms (Dugusia) bristleworms Bivalves -- clams, scallops, mussels Echinoidea -- sea urchins, sand Chelicerata Cephalochordata -- lancelets (organisms studied in detail in Demospongia -- spongin or Hydrazoa -- hydras, some corals Trematoda -- flukes (parasitic) Oligochaetes -- earthworms (Lumbricus) Cephalopods -- squid, octopus, dollars Arachnida -- spiders, scorpions Mixini -- hagfish siliceous sponges Xiphosura -- horseshoe crabs Bio1AL are underlined) Cubozoa -- box jellyfish, sea wasps Cestoda -- tapeworms (parasitic) Hirudinea -- leeches nautilus Holothuroidea -- sea cucumbers Petromyzontida -- lamprey Mandibulata Calcarea -- calcareous sponges Scyphozoa -- jellyfish, sea nettles Monogenea -- parasitic flatworms Polyplacophora -- chitons Ophiuroidea -- brittle stars Chondrichtyes -- sharks, skates Crustacea -- crustaceans (shrimp, crayfish Scleropongiae -- coralline or Crinoidea -- sea lily, feather stars Actinipterygia -- ray-finned fish tropical reef sponges Hexapoda -- insects (cockroach, fruit fly) Sarcopterygia -- lobed-finned fish Myriapoda Amphibia (frog, newt) Chilopoda -- centipedes Diplopoda -- millipedes Reptilia (snake, turtle) Aves (chicken, hummingbird) Mammalia -
Animal Kingdom
ANIMAL KINGDOM Characteristics of Animals Heterotrophic Can’t make their own food Mobile Multicellular Diploid cells Sexual reproduction No cell wall Blastula Fertilized egg cell divides to form a hollow ball of cells Forms 3 layers – ectoderm, endoderm, mesoderm Tissues Group of cells with a common function Characteristics of Animals Body symmetry Asymmetrical – irregular in shape Ex: sponges Radial symmetry – body parts around a central axis Ex: sea anemone Bilateral symmetry – distinct right and left halves Characteristics of Animals Internal body cavity Coelom – fluid-filled space between the body wall and digestive tract Acoelomates – animal with no body cavity Pseudocoelomates – “false coelom” Located between mesoderm and endoderm Coelomates – body cavity located entirely in the mesoderm Kinds of Animals Divided into two groups Invertebrates Animals without a backbone Vertebrates Animals with a backbone Invertebrates Sponges Cnidarians Flatworms and Roundworms SPONGES Phylum – Porifera Asymmetrical body form Not organized into tissues and organs Ostia – openings in the body wall Where water enters the sponge Oscula – large openings Where water exits the sponge Sessile – attached to the sea bottom or a rock or coral reef and don’t move from that place Filter feeders Can reproduce sexually or asexually CNIDARIANS What kinds of animals are these??? Jellyfish, sea anemones 2 different body forms Medusa – free-floating, jellylike, often shaped like an umbrella Polyp – tubelike and usually -
Invertebrates Invertebrates: • Are Animals Without Backbones • Represent 95% of the Animal Kingdom Animal Diversity Morphological Vs
Invertebrates Invertebrates: • Are animals without backbones • Represent 95% of the animal kingdom Animal Diversity Morphological vs. Molecular Character Phylogeny? A tree is a hypothesis supported or not supported by evidence. Groupings change as new evidence become available. Sponges - Porifera Natural Bath Sponges – over-collected, now uncommon Sponges • Perhaps oldest animal phylum (Ctenphora possibly older) • may represent several old phyla, some now extinct ----------------Ctenophora? Sponges - Porifera • Mostly marine • Sessile animals • Lack true tissues; • Have only a few cell types, cells kind of independent • Most have no symmetry • Body resembles a sac perforated with holes, system of canals. • Strengthened by fibers of spongin, spicules Sponges have a variety of shapes Sponges Pores Choanocyte Amoebocyte (feeding cell) Skeletal Water fiber flow Central cavity Flagella Choanocyte in contact with an amoebocyte Sponges - Porifera • Sessile filter feeder • No mouth • Sac-like body, perforated by pores. • Interior lined by flagellated cells (choanocytes). Flagellated collar cells generate a current, draw water through the walls of the sponge where food is collected. • Amoeboid cells move around in the mesophyll and distribute food. Sponges - Porifera Grantia x.s. Sponge Reproduction Asexual reproduction • Fragmentation or by budding. • Sponges are capable of regeneration, growth of a whole from a small part. Sexual reproduction • Hermaphrodites, produce both eggs and sperm • Eggs and sperm released into the central cavity • Produces -
Understanding Paraxial Mesoderm Development and Sclerotome Specification for Skeletal Repair Shoichiro Tani 1,2, Ung-Il Chung2,3, Shinsuke Ohba4 and Hironori Hojo2,3
Tani et al. Experimental & Molecular Medicine (2020) 52:1166–1177 https://doi.org/10.1038/s12276-020-0482-1 Experimental & Molecular Medicine REVIEW ARTICLE Open Access Understanding paraxial mesoderm development and sclerotome specification for skeletal repair Shoichiro Tani 1,2, Ung-il Chung2,3, Shinsuke Ohba4 and Hironori Hojo2,3 Abstract Pluripotent stem cells (PSCs) are attractive regenerative therapy tools for skeletal tissues. However, a deep understanding of skeletal development is required in order to model this development with PSCs, and for the application of PSCs in clinical settings. Skeletal tissues originate from three types of cell populations: the paraxial mesoderm, lateral plate mesoderm, and neural crest. The paraxial mesoderm gives rise to the sclerotome mainly through somitogenesis. In this process, key developmental processes, including initiation of the segmentation clock, formation of the determination front, and the mesenchymal–epithelial transition, are sequentially coordinated. The sclerotome further forms vertebral columns and contributes to various other tissues, such as tendons, vessels (including the dorsal aorta), and even meninges. To understand the molecular mechanisms underlying these developmental processes, extensive studies have been conducted. These studies have demonstrated that a gradient of activities involving multiple signaling pathways specify the embryonic axis and induce cell-type-specific master transcription factors in a spatiotemporal manner. Moreover, applying the knowledge of mesoderm development, researchers have attempted to recapitulate the in vivo development processes in in vitro settings, using mouse and human PSCs. In this review, we summarize the state-of-the-art understanding of mesoderm development and in vitro modeling of mesoderm development using PSCs. We also discuss future perspectives on the use of PSCs to generate skeletal tissues for basic research and clinical applications. -
BIOSC 041 Overview of Animal Diversity: Animal Body Plans
BIOSC 041 Overview of Animal Diversity: Animal Body Plans Reference: Chapter 32 Outline v Definition and major characteristics of animals v Dividing animals into groups based on: § Body symmetry § Tissues § Type of body cavity § Protostome vs deuterostome development v Animal Phylogeny What is an Animal? v Scientists have identified 1.3 million living species of animals v The definition of an animal § Multicellular § Heterotrophic eukaryotes § Possess tissues that develop from embryonic layers v Common characteristics describe the group 1. Common mode of nutrition 2. Cell structure and specialization 3. Reproduction and development 1. Characteristics of Animals: Nutrition v Animals are heterotrophs (“other-eater”) § Obtain nutrition either from other living organisms or from nonliving organic material § Primary consumers (herbivores), secondary consumers (eat herbivores), tertiary consumers (eat carnivores), and/or detritovores (eat detritus- decaying plants/ animals, feces) 2. Characteristics of Animals: Cell Structure and Specialization 1. Animals are multicellular eukaryotes (Note: single-celled eukaryotes with animal-like behavior are grouped as Protists, such as amoeba) 2. Animal cells lack cell walls 3. Bodies are held together by structural proteins like collagen 4. Bodies are organized into tissues, organs, and organ systems § Tissues are groups of cells that have a common structure, and/or function § Nervous tissue and muscle tissue are unique to animals Amoeba: a protist, not a true animal 3. Characteristics of Animals: Reproduction and Development v Most animals reproduce sexually, with the diploid stage dominating the life cycle v Development occurs in specific stages 1. Fertilization to form zygote 2. Zygote undergoes rapid cell division called cleavage 3. Cleavage leads to formation of a multicellular, hollow blastula (ex: whitefish blastula slides from lab, with cells undergoing rapid mitosis) 4.