Organically-preserved multicellular eukaryote from the early Ediacaran Nyborg Formation, Arctic Norway

Abstract Eukaryotic multicellularity originated in the Mesoproterozoic Era and evolved multiple times since, yet early multicellular fossils are scarce until the terminal Neoproterozoic and often restricted to cases of exceptional preservation. Here we describe unusual organically-preserved fossils from mudrocks, that provide support for the presence of organisms with differentiated cells (potentially an epithelial layer) in the late Neoproterozoic. Cyathinema digermulense gen. et sp. nov. from the Nyborg Formation, Vestertana Group, Digermulen Peninsula in Arctic Norway, is a new carbonaceous organ-taxon which consists of stacked tubes with cup-shaped ends. It represents parts of a larger organism (multicellular eukaryote or a colony), likely with greater preservation potential than its other elements. Arrangement of open-ended tubes invites comparison with cells of an epithelial layer present in a variety of eukaryotic clades. This tissue may have benefitted the organism in: avoiding overgrowth, limiting fouling, reproduction, or water filtration. C. digermulense shares characteristics with extant and fossil groups including red algae and their fossils, demosponge larvae and putative sponge fossils, colonial protists, and nematophytes. Regardless of its precise affinity, C. digermulense was a complex and likely benthic marine eukaryote exhibiting cellular differentiation, and a rare occurrence of early multicellularity outside of Konservat-Lagerstätten.

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The Developmental Capacity of Nuclei taken from Intestinal Epithelium Cells of Feeding Tadpoles

Development ◽

10.1242/dev.10.4.622 ◽

1962 ◽

Vol 10 (4) ◽

pp. 622-640 ◽

Cited By ~ 2

Author(s):

J. B. Gurdon

Keyword(s):

Genetic Information ◽

Cellular Differentiation ◽

Cell Types ◽

Nuclear Transplantation ◽

Differentiated Cells ◽

Developmental Capacity ◽

Nuclear Changes ◽

Different Cell Types ◽

Epithelium Cells ◽

Saline Medium

An important problem in embryology is whether the differentiation of cells depends upon a stable restriction of the genetic information contained in their nuclei. The technique of nuclear transplantation has shown to what extent the nuclei of differentiating cells can promote the formation of different cell types (e.g. King & Briggs, 1956; Gurdon, 1960c). Yet no experiments have so far been published on the transplantation of nuclei from fully differentiated normal cells. This is partly because it is difficult to obtain meaningful results from such experiments. The small amount of cytoplasm in differentiated cells renders their nuclei susceptible to damage through exposure to the saline medium, and this makes it difficult to assess the significance of the abnormalities resulting from their transplantation. It is, however, very desirable to know the developmental capacity of such nuclei, since any nuclear changes which are necessarily involved in cellular differentiation must have already taken place in cells of this kind.

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Embryogenesis and larval differentiation in sponges

Canadian Journal of Zoology ◽

10.1139/z05-170 ◽

2006 ◽

Vol 84 (2) ◽

pp. 262-287 ◽

Cited By ~ 60

Author(s):

S P Leys ◽

A V Ereskovsky

Keyword(s):

Sexual Reproduction ◽

Cellular Differentiation ◽

Original Data ◽

Body Plan ◽

Cellular Material ◽

Sensory Organs ◽

Differentiated Cells ◽

Cell Layers ◽

Anterior Posterior

Having descended from the first multicellular animals on earth, sponges are a key group in which to seek innovations that form the basis of the metazoan body plan, but sponges themselves have a body plan that is extremely difficult to reconcile with that of other animals. Adult sponges lack overt anterior–posterior polarity and sensory organs, and whether they possess true tissues is even debated. Nevertheless, sexual reproduction occurs as in other metazoans, with the development of embryos through a structured series of cellular divisions and organized rearrangements of cellular material, using both mesenchymal and epithelial movements to form a multicellular embryo. In most cases, the embryo undergoes morphogenesis into a spatially organized larva that has several cell layers, anterior–posterior polarity, and sensory capabilities. Here we review original data on the mode of cleavage, timing of cellular differentiation, and the mechanisms involved in the organization of differentiated cells to form the highly structured sponge larva. Our ultimate goal is to develop interpretations of the phylogenetic importance of these data within the Porifera and among basal Metazoa.

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Expression of p53 during mouse embryogenesis

Development ◽

10.1242/dev.113.3.857 ◽

1991 ◽

Vol 113 (3) ◽

pp. 857-865 ◽

Cited By ~ 4

Author(s):

P. Schmid ◽

A. Lorenz ◽

H. Hameister ◽

M. Montenarh

Keyword(s):

Gene Expression ◽

Cellular Differentiation ◽

Cellular Proliferation ◽

In Situ Hybridisation ◽

Terminal Differentiation ◽

Mouse Embryogenesis ◽

Differentiated Cells ◽

The Brain ◽

P53 Mrna

By in situ hybridisation we have examined the expression of p53 during mouse embryogenesis from day 8.5 to day 18.5 post coitum (p.c.). High levels of p53 mRNA were detected in all cells of the day 8.5 p.c. and 10.5 p.c. mouse embryo. However, at later stages of development, expression became more pronounced during differentiation of specific tissues e.g. of the brain, liver, lung, thymus, intestine, salivary gland and kidney. In cells undergoing terminal differentiation, the level of p53 mRNA declined strongly. In the brain, hybridisation signals were also observed in postmitotic but not yet terminally differentiated cells. Therefore, gene expression of p53 does not appear to be linked with cellular proliferation in this organ. A proposed role for p53 in cellular differentiation is discussed.

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Late Proterozoic–Early Phanerozoic ‘Taphonomic Windows’: The Environmental and Temporal Distribution of Recurrent Modes of Exceptional Preservation

The Paleontological Society Papers ◽

10.1017/s1089332600002904 ◽

2014 ◽

Vol 20 ◽

pp. 289-313

Author(s):

Patrick J. Orr

Keyword(s):

Evolutionary Biology ◽

Intermediate Phase ◽

Temporal Distribution ◽

Exceptional Preservation ◽

Global Environmental ◽

History Of ◽

Type Preservation ◽

Late Neoproterozoic ◽

Diagenetic History ◽

Organic Remains

Exceptional biotas—those in which the non-biomineralized tissues of organisms are preserved—are an important record of the evolutionary biology of the late Neoproterozoic—early Phanerozoic interval. Most of these biotas exhibit one of four modes of preservation: preservation of either 1) internal and external detail (Doushantuo-type preservation) or, 2) external cuticles (Orsten-type preservation) in calcium phosphate; 3) coating in pyrite films and infills (Beecher's Bed-type preservation); and 4) preservation of organic remains (Burgess Shale-type preservation). The global environmental and temporal distribution of each mode of preservation is reasonably well constrained, but not why these taphonomic windows existed when they did. The late Neoproterozoic – early Phanerozoic interval is characterized by complex, interlinked, physical, geochemical and biological changes to the Earth's biosphere and geosphere. The changing ecology of marine environments (from matground to mixgrounds: the ‘Agronomic Revolution’) occurred via an intermediate phase of stiffened, but not microbially bound sediments that extended the interval over which exceptional preservation occurred. Prolonged eustatic sea-level rise across flat-lying continental platforms ensured environments conducive to exceptional preservation were developed and, critically, sustained over large contiguous areas. During this, regolith on continental surfaces was recycled, providing an integral source of sediment and ions relevant to mineral authigenesis. Superimposed on these broad-scale changes are specific drivers that controlled the duration of individual taphonomic windows; elucidating these requires a better understanding of the environmental context and diagenetic history of fossiliferous successions at the intra-basinal scale.

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The Emerging Role of Galectins and O-GlcNAc Homeostasis in Processes of Cellular Differentiation

Cells ◽

10.3390/cells9081792 ◽

2020 ◽

Vol 9 (8) ◽

pp. 1792 ◽

Cited By ~ 1

Author(s):

Rada Tazhitdinova ◽

Alexander V. Timoshenko

Keyword(s):

Cancer Biology ◽

Cellular Differentiation ◽

Current Knowledge ◽

Expression Profiles ◽

Cell Types ◽

Innovative Strategies ◽

Protein Levels ◽

Differentiated Cells ◽

Independent Functions

Galectins are a family of soluble β-galactoside-binding proteins with diverse glycan-dependent and glycan-independent functions outside and inside the cell. Human cells express twelve out of sixteen recognized mammalian galectin genes and their expression profiles are very different between cell types and tissues. In this review, we summarize the current knowledge on the changes in the expression of individual galectins at mRNA and protein levels in different types of differentiating cells and the effects of recombinant galectins on cellular differentiation. A new model of galectin regulation is proposed considering the change in O-GlcNAc homeostasis between progenitor/stem cells and mature differentiated cells. The recognition of galectins as regulatory factors controlling cell differentiation and self-renewal is essential for developmental and cancer biology to develop innovative strategies for prevention and targeted treatment of proliferative diseases, tissue regeneration, and stem-cell therapy.

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CELLULAR DIFFERENTIATION OF THE IMMUNE SYSTEM OF MICE

Journal of Experimental Medicine ◽

10.1084/jem.129.1.185 ◽

1969 ◽

Vol 129 (1) ◽

pp. 185-199 ◽

Cited By ~ 24

Author(s):

G. M. Shearer ◽

G. Cudkowicz ◽

R. L. Priore

Keyword(s):

Immune System ◽

Specific Antibody ◽

Cellular Differentiation ◽

Single Cells ◽

Donor Cell ◽

Cell Suspensions ◽

The Other ◽

Spleen Cells ◽

Igg Antibody ◽

Differentiated Cells

Spleen cell suspensions of primed donor mice containing precursors of immunocytes have been transplanted into X-irradiated recipient mice 122–138 days after immunization. Following secondary stimulation with antigen (sheep erythrocytes), these precursors, called antigen-sensitive units (ASU), gave rise to progeny cells secreting specific antibody in the spleens of recipients. Single cells releasing IgM hemolysins (direct plaque-forming cells or PFC), IgG hemolysins (indirect PFC), and hemagglutinins (cluster-forming cells or CFC) were enumerated. By transplanting graded and limiting numbers of primed spleen cells, inocula were found which contained one or a few ASU reaching the recipient spleens. We estimated, thereby, the frequency of ASU detectable by our procedures in donor cell suspensions. The values obtained from direct and in-indirect plaque assays, and from cluster assays were 1 in ∼8.0 x 105, 1 in ∼4.4 x 105, and 1 in ∼5.9 x 105 nucleated spleen cells, respectively. The number of splenic ASU for direct PFC was not greater than that of unimmunized mice; however, immunization greatly increased the number of splenic ASU for indirect PFC and for CFC. By applying to each recipient spleen direct and indirect plaque tests and cluster tests, we found that positivity for each type of immunocyte was independent from that of the other two types. These results confirm the unipotent nature of splenic ASU in general, and document the commitment of ASU primed with SRBC to generate progeny cells secreting antibody of a single molecular (IgM or IgG) or functional (lysin or agglutinin) class. We concluded that splenic ASU are composed of relatively differentiated cells of the immune system of mice. With respect to specificity and class differentiation, ASU appear to be as specialized as antibody-producing cells themselves. Our results did not support the view that ASU-derived clonal populations shift from IgM to IgG antibody production.

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Macroscopic carbonaceous compressions in a terminal Proterozoic shale: A systematic reassessment of the Miaohe biota, south China

Journal of Paleontology ◽

10.1017/s0022336000041743 ◽

2002 ◽

Vol 76 (2) ◽

pp. 347-376 ◽

Cited By ~ 129

Author(s):

Shuhai Xiao ◽

Xunlai Yuan ◽

Michael Steiner ◽

Andrew H. Knoll

Keyword(s):

Green Algae ◽

South China ◽

Brown Algae ◽

Body Plan ◽

Early Cambrian ◽

Burgess Shale ◽

New Materials ◽

Exceptional Preservation ◽

Animal Remains ◽

Late Neoproterozoic

Carbonaceous compression fossils in shales of the uppermost Doushantuo Formation (ca. 555-590 Ma) at Miaohe in the Yangtze Gorges area provide a rare Burgess-Shale-type taphonomic window on terminal Proterozoic biology. More than 100 macrofossil species have been described from Miaohe shales, but in an examination of published and new materials, we recognize only about twenty distinct taxa, including Aggregatosphaera miaoheensis new gen. and sp. Most of these fossils can be interpreted unambiguously as colonial prokaryotes or multicellular algae. Phylogenetically derived coenocytic green algae appear to be present, as do regularly bifurcating thalli comparable to red and brown algae. At least five species have been interpreted as metazoans by previous workers. Of these, Protoconites minor and Calyptrina striata most closely resemble animal remains; either or both could be the organic sheaths of cnidarian scyphopolyps, although an algal origin cannot be ruled out for P. minor. Despite exceptional preservation, the Miaohe assemblage contains no macroscopic fossils that can be interpreted with confidence as bilaterian animals. In combination with other late Neoproterozoic and Early Cambrian body fossils and trace fossils, the Doushantuo assemblage supports the view that body-plan diversification within bilaterian phyla was largely a Cambrian event.

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Observations on an endozoic red alga

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400033683 ◽

1967 ◽

Vol 47 (1) ◽

pp. 223-232 ◽

Cited By ~ 5

Author(s):

A. D. Boney ◽

E. B. White

Keyword(s):

Red Algae ◽

Plant Material ◽

Red Alga ◽

Host Material ◽

Critical Study ◽

Rare Occurrence ◽

Preliminary Examination ◽

Extensive Growth ◽

Shape And Size ◽

Comprehensive Study

A description is given of a filamentous red alga which was found growing within a sponge collected from the sublittoral off Santander, Spain. The plant appears to be closely related to Acrochaetium spiculiphilum Dawson. A survey is given of the specific characters available for the typification of the known partially and completely endozoic Acrochaetium species, and some suggestions made on the more important lines of study.IntroductionDuring the summer of 1957 some specimens of the keratinous sponge Haliclona were collected from the sublittoral off Santander, Spain, by Mr G. R. Forster. Certain of the specimens bore extensive areas of red, and on preliminary examination this colour was found to be due to the filaments of a red alga showing an extensive ramifying growth within the skeleton of the sponge. The drawings and cell measurements to be reported were made from the plant material by A. D. B. soon after its collection. This information has been retained pending a more comprehensive study of endophytic and endozoic red algae. Work is now in progress on these lines (mainly by E. B. W.), and a re-examination of the Santander material has enabled us to make a critical study of the data available for a precise typification of plants of this habit. Further, since the association of endozoic filamentous red algae with sponges appears to be of rare occurrence, any examples need to be fully described.Description of PlantThe cells were of variable shape and size, and contained much-dissected parietal chromatophores (Fig. 1 a). Individual filaments tended to be closely packed together within the host (Fig. 1 b), and there was no extensive growth of erect filaments outside of the host material.

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Lamin A/C mutation associated with lipodystrophy influences adipogenic differentiation of stem cells through interaction with Notch signaling

Biochemistry and Cell Biology ◽

10.1139/bcb-2017-0210 ◽

2018 ◽

Vol 96 (3) ◽

pp. 342-348 ◽

Cited By ~ 9

Author(s):

K. Perepelina ◽

R. Dmitrieva ◽

E. Ignatieva ◽

A. Borodkina ◽

A. Kostareva ◽

...

Keyword(s):

Stem Cells ◽

Notch Signaling ◽

Cellular Differentiation ◽

Adipogenic Differentiation ◽

Lamin A ◽

Cellular Functions ◽

Gene Encoding ◽

Differentiated Cells ◽

Lmna Mutation ◽

Notch Activation

Lamins A and C are involved in many cellular functions, owing to its ability to bind chromatin and transcription factors and affect their properties. Mutations of the LMNA gene encoding lamin A/C affect differentiation capacity of stem cells. However, the signaling pathways involved in interactions with lamins during cellular differentiation remain unclear. Lipodystrophy associated with LMNA mutation R482L causes loss of fat tissue. In this study we investigated the role of LMNA mutation R482L in modulating Notch signaling activity in the adipogenic differentiation of mesenchymal stem cells. Notch was activated using lentiviral Notch intracellular domain. Activation of Notch was estimated through the expression of Notch-responsive genes by qPCR and by activation of a luciferase CSL-reporter construct. The effect of LMNA mutation on Notch activation and adipogenic differentiation was analyzed in cells bearing lentiviral LMNA WT or LMNA R482L. We show that, when Notch is activated, LMNA R482L contributes to down-regulation of Notch activation in undifferentiated and differentiated cells, and decreases adipogenic differentiation. Thus, lamin A/C interacts with Notch signaling, thereby influencing cellular differentiation, and point mutation in LMNA could halt this interaction.

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Trace elements and Sr and C isotopic signatures in late Neoproterozoic and earliest Cambrian sedimentary organic matter from siliciclastic successions in the East European Platform

Geological Magazine ◽

10.1017/s0016756898001150 ◽

1998 ◽

Vol 135 (4) ◽

pp. 537-551 ◽

Cited By ~ 15

Author(s):

S. B. FELITSYN ◽

G. VIDAL ◽

M. MOCZYDŁOWSKA

Keyword(s):

Organic Matter ◽

East European Platform ◽

Sedimentary Organic Matter ◽

East European ◽

Isotopic Signatures ◽

Exceptional Preservation ◽

Upper Vendian ◽

Acid Processing ◽

Late Neoproterozoic ◽

Marine Basin

Sedimentary organic matter deriving from tubes of sabelliditids, vendotaenids, sapropelic films and kerogens was extracted by acid processing from Upper Vendian siliciclastic successions in the East European Platform. Elemental composition obtained by instrumental neutron activation analysis (INAA) displays the increasing cobalt (Co) concentration from 1 ppm at the bottom of Upper Vendian succession to about 800 ppm in the uppermost part near the Precambrian–Cambrian boundary. This distribution is recorded in all studied successions and is not related to resistant minerals that survived acid treatment. The enrichment in Co and other metals in the sedimentary organic matter is inferred to be caused by the bloom of cyanobacterial microbiota, and bonding of metals in decaying sedimentary organic matter during pre-burial bacterial reworking and post-burial early diagenesis in a low energy, stagnant depositional basin during Kotlin times. The positive Ceanom in probable benthic sabelliditids, and the exceptional preservation of sedimentary organic matter from Kotlinian strata, indicate the anaerobic conditions during their sedimentation. Clear correlations between 87Sr/86Sr, δ13C and Co imply the secondary isotopic signatures of Sr and C in sedimentary organic matter deriving from a restricted epicontinental marine basin.

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