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Sun W, Yin Z, Liu P, Zhu M, Donoghue P. Developmental biology of Spiralicellula and the Ediacaran origin of crown metazoans. Proc Biol Sci 2024; 291:20240101. [PMID: 38808442 DOI: 10.1098/rspb.2024.0101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Accepted: 04/23/2024] [Indexed: 05/30/2024] Open
Abstract
The early Ediacaran Weng'an biota (Doushantuo Formation, South China) provides a rare window onto the period of Earth history in which molecular timescales have inferred the initial phase of crown-metazoan diversification. Interpretation of the embryo-like fossils that dominate the biota remains contentious because they are morphologically simple and so difficult to constrain phylogenetically. Spiralicellula from the Weng'an biota is distinguished by spiral internal bodies, allied through development to Megasphaera or Helicoforamina and interpreted variously as metazoan embryos, encysting protists, or chlorophycean green algae. Here we show, using X-ray microtomography, that Spiralicellula has a single-layered outer envelope and no more than 32 internal cells, often preserving a nucleus and yolk granules. There is no correlation between the extent of spiral development and the number of component cells; rather, the spiral developed with each palintomic stage, associated with cell disaggregation and reorientation. Evidence for envelope thinning and cell loss was observed in all developmental stages, reflecting non-deterministic shedding of gametes or amoebae. The developmental biology of Spiralicellula is similar to Megasphaera and Helicoforamina, which otherwise exhibit more rounds of palintomy. We reject a crown-metazoan affinity for Spiralicellula and all other components of the Weng'an biota, diminishing the probability of crown-metazoan diversification before the early Ediacaran.
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Affiliation(s)
- Weichen Sun
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China
| | - Zongjun Yin
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China
- Nanjing College, University of Chinese Academy of Sciences, Nanjing 211135, People's Republic of China
| | - Pengju Liu
- Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, People's Republic of China
| | - Maoyan Zhu
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China
- Nanjing College, University of Chinese Academy of Sciences, Nanjing 211135, People's Republic of China
| | - Philip Donoghue
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
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2
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Zhang Y, Zhang X, Liu C. Asynchronized cell division in embryo‐like fossils from the Ediacaran Zhenba microfossil assemblage. Evol Dev 2022; 24:189-195. [DOI: 10.1111/ede.12423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/26/2022] [Accepted: 09/04/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Yuan Zhang
- Department of Geology, State Key Laboratory of Continental Dynamics, and Shaanxi Key Laboratory of Early Life and Environments Northwest University Xi'an China
| | - Xingliang Zhang
- Department of Geology, State Key Laboratory of Continental Dynamics, and Shaanxi Key Laboratory of Early Life and Environments Northwest University Xi'an China
- Nanjing Institute of Geology and Paleontology Chinese Academy of Sciences Nanjing China
| | - Cong Liu
- Department of Geology, State Key Laboratory of Continental Dynamics, and Shaanxi Key Laboratory of Early Life and Environments Northwest University Xi'an China
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3
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Yin Z, Sun W, Liu P, Chen J, Bottjer DJ, Li J, Zhu M. Diverse and complex developmental mechanisms of early Ediacaran embryo-like fossils from the Weng'an Biota, southwest China. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210032. [PMID: 35125006 PMCID: PMC8819369 DOI: 10.1098/rstb.2021.0032] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The origin and early evolution of animal development remain among the many deep, unresolved problems in evolutionary biology. As a compelling case for the existence of pre-Cambrian animals, the Ediacaran embryo-like fossils (EELFs) from the Weng'an Biota (approx. 609 Myr old, Doushantuo Formation, South China) have great potential to cast light on the origin and early evolution of animal development. However, their biological implications can be fully realized only when their phylogenetic positions are correctly established, and unfortunately, this is the key problem under debate. As a significant feature of developmental biology, the cell division pattern (CDP) characterized by the dynamic spatial arrangement of cells and associated developmental mechanisms is critical to reassess these hypotheses and evaluate the diversity of the EELFs; however, their phylogenetic implications have not been fully realized. Additionally, the scarcity of fossil specimens representing late developmental stages with cell differentiation accounts for much of this debate too. Here, we reconstructed a large number of EELFs using submicron resolution X-ray tomographic microscopy and focused on the CDPs and associated developmental mechanisms as well as features of cell differentiation. Four types of CDPs and specimens with cell differentiation were identified. Contrary to the prevailing view, our results together with recent studies suggest that the diversity and complexity of developmental mechanisms documented by the EELFs are much higher than is often claimed. The diverse CDPs and associated development features including palintomic cleavage, maternal nutrition, asymmetric cell divisions, symmetry breaking, establishment of polarity or axis, spatial cell migration and differentiation constrain some, if not all, EELFs as total-group metazoans. This article is part of the theme issue ‘The impact of Chinese palaeontology on evolutionary research’.
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Affiliation(s)
- Zongjun Yin
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.,Centre for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.,Nanjing College, University of Chinese Academy of Sciences, Nanjing 211135, People's Republic of China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Weichen Sun
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.,University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Pengju Liu
- Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, People's Republic of China
| | - Junyuan Chen
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China
| | - David J Bottjer
- Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Jinhua Li
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing 100029, People's Republic of China
| | - Maoyan Zhu
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.,Centre for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.,Nanjing College, University of Chinese Academy of Sciences, Nanjing 211135, People's Republic of China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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4
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Lindsey CR, Rosenzweig F, Herron MD. Phylotranscriptomics points to multiple independent origins of multicellularity and cellular differentiation in the volvocine algae. BMC Biol 2021; 19:182. [PMID: 34465312 PMCID: PMC8408923 DOI: 10.1186/s12915-021-01087-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/08/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The volvocine algae, which include the single-celled species Chlamydomonas reinhardtii and the colonial species Volvox carteri, serve as a model in which to study the evolution of multicellularity and cellular differentiation. Studies reconstructing the history of this group have by and large relied on datasets of one to a few genes for phylogenetic inference and ancestral character state reconstruction. As a result, volvocine phylogenies lack concordance depending on the number and/or type of genes (i.e., chloroplast vs nuclear) chosen for phylogenetic inference. While multiple studies suggest that multicellularity evolved only once in the volvocine algae, that each of its three colonial families is monophyletic, and that there have been at least three independent origins of cellular differentiation in the group, other studies call into question one or more of these conclusions. An accurate assessment of the evolutionary history of the volvocine algae requires inference of a more robust phylogeny. RESULTS We performed RNA sequencing (RNA-seq) on 55 strains representing 47 volvocine algal species and obtained similar data from curated databases on 13 additional strains. We then compiled a dataset consisting of transcripts for 40 single-copy, protein-coding, nuclear genes and subjected the predicted amino acid sequences of these genes to maximum likelihood, Bayesian inference, and coalescent-based analyses. These analyses show that multicellularity independently evolved at least twice in the volvocine algae and that the colonial family Goniaceae is not monophyletic. Our data further indicate that cellular differentiation arose independently at least four, and possibly as many as six times, within the volvocine algae. CONCLUSIONS Altogether, our results demonstrate that multicellularity and cellular differentiation are evolutionarily labile in the volvocine algae, affirming the importance of this group as a model system for the study of major transitions in the history of life.
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Affiliation(s)
- Charles Ross Lindsey
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Frank Rosenzweig
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Parker H. Petit Institute for Bioengineering and Biosciences, Atlanta, USA
| | - Matthew D Herron
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
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5
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Strother PK, Brasier MD, Wacey D, Timpe L, Saunders M, Wellman CH. A possible billion-year-old holozoan with differentiated multicellularity. Curr Biol 2021; 31:2658-2665.e2. [PMID: 33852871 DOI: 10.1016/j.cub.2021.03.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/07/2020] [Accepted: 03/15/2021] [Indexed: 02/05/2023]
Abstract
Sediments of the Torridonian sequence of the Northwest Scottish Highlands contain a wide array of microfossils, documenting life in a non-marine setting a billion years ago (1 Ga).1-4 Phosphate nodules from the Diabaig Formation at Loch Torridon preserve microorganisms with cellular-level fidelity,5,6 allowing for partial reconstruction of the developmental stages of a new organism, Bicellum brasieri gen. et sp. nov. The mature form of Bicellum consists of a solid, spherical ball of tightly packed cells (a stereoblast) of isodiametric cells enclosed in a monolayer of elongated, sausage-shaped cells. However, two populations of naked stereoblasts show mixed cell shapes, which we infer to indicate incipient development of elongated cells that were migrating to the periphery of the cell mass. These simple morphogenetic movements could be explained by differential cell-cell adhesion.7,8 In fact, the basic morphology of Bicellum is topologically similar to that of experimentally produced cell masses that were shown to spontaneously segregate into two distinct domains based on differential cadherin-based cell adhesion.9 The lack of rigid cell walls in the stereoblast renders an algal affinity for Bicellum unlikely: its overall morphology is more consistent with a holozoan origin. Unicellular holozoans are known today to form multicellular stages within complex life cycles,10-13 so the occurrence of such simple levels of transient multicellularity seen here is consistent with a holozoan affinity. Regardless of precise phylogenetic placement, these fossils demonstrate simple cell differentiation and morphogenic processes that are similar to those seen in some metazoans today.
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Affiliation(s)
- Paul K Strother
- Department of Earth & Environmental Sciences, Weston Observatory of Boston College, 381 Concord Road, Weston, MA 02493, USA.
| | - Martin D Brasier
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - David Wacey
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Leslie Timpe
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
| | - Martin Saunders
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Charles H Wellman
- Department of Animal & Plant Sciences, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield S10 2TN, UK
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6
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Sun W, Yin Z, Cunningham JA, Liu P, Zhu M, Donoghue PCJ. Nucleus preservation in early Ediacaran Weng'an embryo-like fossils, experimental taphonomy of nuclei and implications for reading the eukaryote fossil record. Interface Focus 2020; 10:20200015. [PMID: 32637068 PMCID: PMC7333911 DOI: 10.1098/rsfs.2020.0015] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2020] [Indexed: 11/20/2022] Open
Abstract
The challenge of identifying fossilized organelles has long hampered attempts to interpret the fossil record of early eukaryote evolution. We explore this challenge through experimental taphonomy of nuclei in a living eukaryote and microscale physical and chemical characterization of putative nuclei in embryo-like fossils from the early Ediacaran Weng'an Biota. The fossil nuclei exhibit diverse preservational modes that differ in shape, presence or absence of an inner body and the chemistry of the associated mineralization. The nuclei are not directly fossilized; rather, they manifest as external moulds. Experimental taphonomy of epidermal cells from the common onion (Allium cepa) demonstrates that nuclei are more decay resistant than their host cells, generally maintaining their physical dimensions for weeks to months post-mortem, though under some experimental conditions they exhibit shrinkage and/or become shrouded in microbial biofilms. The fossil and experimental evidence may be rationalized in a single taphonomic pathway of selective mineralization of the cell cytoplasm, preserving an external mould of the nucleus that is itself resistant to both decay and mineral replication. Combined, our results provide both a secure identification of the Weng'an nuclei as well as the potential of a fossil record of organelles that might help arbitrate in long-standing debates over the relative and absolute timing of the evolutionary assembly of eukaryote-grade cells.
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Affiliation(s)
- Weichen Sun
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.,University of Science and Technology of China, Hefei 230026, People's Republic of China
| | - Zongjun Yin
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.,Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China
| | - John A Cunningham
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Pengju Liu
- Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100043, People's Republic of China
| | - Maoyan Zhu
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.,Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.,College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Philip C J Donoghue
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
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7
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Shuffling type of biological evolution based on horizontal gene transfer and the biosphere gene pool hypothesis. Biosystems 2020; 193-194:104131. [DOI: 10.1016/j.biosystems.2020.104131] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 03/12/2020] [Accepted: 03/12/2020] [Indexed: 02/08/2023]
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8
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Yin Z, Sun W, Liu P, Zhu M, Donoghue PCJ. Developmental biology of Helicoforamina reveals holozoan affinity, cryptic diversity, and adaptation to heterogeneous environments in the early Ediacaran Weng'an biota (Doushantuo Formation, South China). SCIENCE ADVANCES 2020; 6:eabb0083. [PMID: 32582859 PMCID: PMC7292632 DOI: 10.1126/sciadv.abb0083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/21/2020] [Indexed: 06/11/2023]
Abstract
The exceptional fossil preservation of the early Ediacaran Weng'an biota provides a unique window on the interval of Earth history in which animal lineages emerged. It preserves a diversity of similarly ornamented encysted developmental stages previously interpreted as different developmental stages of one taxon. Although Helicoforamina wenganica is distinguished from other forms by a helical groove or canal, it has been interpreted as a developmental stage of cooccurring metazoan, nonmetazoan holozoan, or green algal taxa. Using x-ray microtomography, we show that Helicoforamina developed through one-, four-, and eight-cell stages, to hundreds and thousands of cells. Putative hatchlings are artifacts of incompletely preserved cyst walls. Our results preclude inclusion of Helicoforamina into life cycles assembled from other components of the Weng'an biota but support a holozoan affinity. The similarly ornamented encysted forms shared among the diverse Weng'an biota represent parallel adaptations to the temporally and spatially heterogeneous Ediacaran shallow marine environments.
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Affiliation(s)
- Zongjun Yin
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China
- CAS Center for Excellence in Life and Paleoenvironment, Nanjing 210008, China
| | - Weichen Sun
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China
- CAS Center for Excellence in Life and Paleoenvironment, Nanjing 210008, China
- University of Science and Technology of China, Hefei 230026, China
| | - Pengju Liu
- Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
| | - Maoyan Zhu
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China
- CAS Center for Excellence in Life and Paleoenvironment, Nanjing 210008, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Philip C. J. Donoghue
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
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9
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Yin Z, Vargas K, Cunningham J, Bengtson S, Zhu M, Marone F, Donoghue P. The Early Ediacaran Caveasphaera Foreshadows the Evolutionary Origin of Animal-like Embryology. Curr Biol 2019; 29:4307-4314.e2. [DOI: 10.1016/j.cub.2019.10.057] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/21/2019] [Accepted: 10/29/2019] [Indexed: 01/01/2023]
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10
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Long J, Zhang S, Luo K. Cryogenian magmatic activity and early life evolution. Sci Rep 2019; 9:6586. [PMID: 31036856 PMCID: PMC6488696 DOI: 10.1038/s41598-019-43177-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 03/17/2019] [Indexed: 11/21/2022] Open
Abstract
Data from the Qinling Orogenic Belt in China indicate that a strong magmatic-volcanic event on the Snowball Earth during the Cryogenian age (approximately 720–635 million years ago) was followed by a dynamic period of accelerated evolution of early life through the Ediacaran period. The studied volcanics of the Cryogenian Yaolinghe group are mainly represented by andesite, dacite and rhyolite, with minor amounts of basalt, trachy andesite and trachyte towards the top, which formed in the environment of an active island arc related to a continental margin. Compared with average felsic volcanics, the studied Cryogenian marine volcanic strata are enriched (1.5–30.6 times) in Co, Cr, Bi, Ni, Se, Ga, As, Cu, Ba, V, and Zn. Elemental concentrations (P, Cd, Co, Ni, and Se) of the studied volcanics are more than 5–26.4 times those in the contemporaneous Liantuo tillite. We propose that Cryogenian magmatic and volcanic activity increased the flux of some trace nutritional elements into the oceans which possibly provided essential nutrients for the development of early life.
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Affiliation(s)
- Jie Long
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shixi Zhang
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Kunli Luo
- Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China.
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11
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Crosby CH, Bailey JV. Experimental precipitation of apatite pseudofossils resembling fossil embryos. GEOBIOLOGY 2018; 16:80-87. [PMID: 29047205 DOI: 10.1111/gbi.12264] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 09/10/2017] [Indexed: 06/07/2023]
Abstract
Certain phosphatic grains preserved in the rock record are interpreted as microfossils representing a diversity of microorganisms from bacteria to fossil embryos. In addition to bona fide primary biological features, phosphatic microfossils and fossil embryos commonly exhibit features that result from abiotic precipitation or diagenetic alteration. Distinguishing between abiotic and primary biological features can be difficult, and some features thought to represent biological tissue could instead be artifacts that are unrelated to the original morphology of a preserved organism. Here, we present experimentally generated, abiotically produced mineral precipitates that morphologically resemble biologically produced features, some of which may be observed in the rock record or noted in extant organisms, including embryos. These findings extend the diversity of biomorphic features known to result from abiotic precipitation.
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Affiliation(s)
- C H Crosby
- Department of Earth Sciences, University of Minnesota-Twin Cities, Minneapolis, MN, USA
| | - J V Bailey
- Department of Earth Sciences, University of Minnesota-Twin Cities, Minneapolis, MN, USA
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12
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Mravec J, Kračun SK, Zemlyanskaya E, Rydahl MG, Guo X, Pičmanová M, Sørensen KK, Růžička K, Willats WGT. Click chemistry-based tracking reveals putative cell wall-located auxin binding sites in expanding cells. Sci Rep 2017; 7:15988. [PMID: 29167548 PMCID: PMC5700113 DOI: 10.1038/s41598-017-16281-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 11/10/2017] [Indexed: 11/09/2022] Open
Abstract
Auxin is a key plant regulatory molecule, which acts upon a plethora of cellular processes, including those related to cell differentiation and elongation. Despite the stunning progress in all disciplines of auxin research, the mechanisms of auxin-mediated rapid promotion of cell expansion and underlying rearrangement of cell wall components are poorly understood. This is partly due to the limitations of current methodologies for probing auxin. Here we describe a click chemistry-based approach, using an azido derivative of indole-3-propionic acid. This compound is as an active auxin analogue, which can be tagged in situ. Using this new tool, we demonstrate the existence of putative auxin binding sites in the cell walls of expanding/elongating cells. These binding sites are of protein nature but are distinct from those provided by the extensively studied AUXIN BINDING PROTEIN 1 (ABP1). Using immunohistochemistry, we have shown the apoplastic presence of endogenous auxin epitopes recognised by an anti-IAA antibody. Our results are intriguingly in line with previous observations suggesting some transcription-independent (non-genomic) activity of auxin in cell elongation.
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Affiliation(s)
- Jozef Mravec
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg-C, Denmark.
| | - Stjepan K Kračun
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg-C, Denmark
| | | | - Maja G Rydahl
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg-C, Denmark
| | - Xiaoyuan Guo
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg-C, Denmark
| | - Martina Pičmanová
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg-C, Denmark
| | - Kasper K Sørensen
- Department of Chemistry, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg-C, Denmark
| | - Kamil Růžička
- CEITEC Masaryk University, Kamenice 5, CZ-625 00, Brno, Czechia
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Rozvojová 263, CZ-165 02 Prague, Czechia
| | - William G T Willats
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg-C, Denmark.
- School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
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13
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Hoffman PF, Abbot DS, Ashkenazy Y, Benn DI, Brocks JJ, Cohen PA, Cox GM, Creveling JR, Donnadieu Y, Erwin DH, Fairchild IJ, Ferreira D, Goodman JC, Halverson GP, Jansen MF, Le Hir G, Love GD, Macdonald FA, Maloof AC, Partin CA, Ramstein G, Rose BEJ, Rose CV, Sadler PM, Tziperman E, Voigt A, Warren SG. Snowball Earth climate dynamics and Cryogenian geology-geobiology. SCIENCE ADVANCES 2017; 3:e1600983. [PMID: 29134193 PMCID: PMC5677351 DOI: 10.1126/sciadv.1600983] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 09/21/2017] [Indexed: 05/02/2023]
Abstract
Geological evidence indicates that grounded ice sheets reached sea level at all latitudes during two long-lived Cryogenian (58 and ≥5 My) glaciations. Combined uranium-lead and rhenium-osmium dating suggests that the older (Sturtian) glacial onset and both terminations were globally synchronous. Geochemical data imply that CO2 was 102 PAL (present atmospheric level) at the younger termination, consistent with a global ice cover. Sturtian glaciation followed breakup of a tropical supercontinent, and its onset coincided with the equatorial emplacement of a large igneous province. Modeling shows that the small thermal inertia of a globally frozen surface reverses the annual mean tropical atmospheric circulation, producing an equatorial desert and net snow and frost accumulation elsewhere. Oceanic ice thickens, forming a sea glacier that flows gravitationally toward the equator, sustained by the hydrologic cycle and by basal freezing and melting. Tropical ice sheets flow faster as CO2 rises but lose mass and become sensitive to orbital changes. Equatorial dust accumulation engenders supraglacial oligotrophic meltwater ecosystems, favorable for cyanobacteria and certain eukaryotes. Meltwater flushing through cracks enables organic burial and submarine deposition of airborne volcanic ash. The subglacial ocean is turbulent and well mixed, in response to geothermal heating and heat loss through the ice cover, increasing with latitude. Terminal carbonate deposits, unique to Cryogenian glaciations, are products of intense weathering and ocean stratification. Whole-ocean warming and collapsing peripheral bulges allow marine coastal flooding to continue long after ice-sheet disappearance. The evolutionary legacy of Snowball Earth is perceptible in fossils and living organisms.
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Affiliation(s)
- Paul F. Hoffman
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
- School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Dorian S. Abbot
- Department of Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA
| | - Yosef Ashkenazy
- Department of Solar Energy and Environmental Physics, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, 84990, Israel
| | - Douglas I. Benn
- School of Geography and Sustainable Development, University of St Andrews, St Andrews, Fife KY16 8YA, UK
| | - Jochen J. Brocks
- Research School of Earth Sciences, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | | | - Grant M. Cox
- Centre for Tectonics, Resources and Exploration (TRaX), Department of Earth Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
- Department of Applied Geology, Curtin University, Bentley, Western Australia 6845, Australia
| | - Jessica R. Creveling
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331–5503, USA
| | - Yannick Donnadieu
- Laboratoire des Sciences du Climat et de l’Environnement (LSCE), Institut Pierre Simon Laplace (IPSL), CEA-CNRS-UVSQ, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
- Aix-Marseille Université, CNRS, L’Institut de recherche pour le développement (IRD), Centre Européen de Recherche et D’enseignement de Géosciences de L’environnement (CEREGE), 13545 Aix-en-Provence, France
| | - Douglas H. Erwin
- Department of Paleobiology, Smithsonian Institution, P.O. Box 37012, MRC 121, Washington, DC 20013–7012, USA
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
| | - Ian J. Fairchild
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - David Ferreira
- Department of Meteorology, University of Reading, Reading, RG6 6BB, UK
| | - Jason C. Goodman
- Department of Environmental Science, Wheaton College, Norton, MA 02766, USA
| | - Galen P. Halverson
- Department of Earth and Planetary Sciences, McGill University, Montréal, Québec H3A 0E8, Canada
| | - Malte F. Jansen
- Department of Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA
| | - Guillaume Le Hir
- Institut de Physique du Globe de Paris, 1, rue Jussieu, 75005 Paris, France
| | - Gordon D. Love
- Department of Earth Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Francis A. Macdonald
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Adam C. Maloof
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
| | - Camille A. Partin
- Department of Geological Sciences, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Gilles Ramstein
- Laboratoire des Sciences du Climat et de l’Environnement (LSCE), Institut Pierre Simon Laplace (IPSL), CEA-CNRS-UVSQ, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Brian E. J. Rose
- Department of Atmospheric and Environmental Sciences, University at Albany, Albany, NY 12222, USA
| | | | - Peter M. Sadler
- Department of Earth Sciences, University of California, Riverside, Riverside, CA 92521, USA
| | - Eli Tziperman
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA
| | - Aiko Voigt
- Institute of Meteorology and Climate Research, Department of Troposphere Research, Karlsruhe Institute of Technology, Karlsruhe, Baden-Württemberg, Germany
- Lamont-Doherty Earth Observatory, Columbia University, P.O. Box 1000, Palisades, NY 10964–1000, USA
| | - Stephen G. Warren
- Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195–1640, USA
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14
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Abstract
This paper addresses the taphonomic processes responsible for fossil preservation in calcium phosphate, or phosphatization. Aside from silicification and rarer examples of carbonaceous compression, phosphatization is the only taphonomic mode claimed to preserve putative subcellular structures. Because this fossilization window can record such valuable information, a comprehensive understanding of its patterns of occurrence and the geochemical processes involved in the replication of soft tissues are critical endeavors. Fossil phosphatization was most abundant during the latest Neoproterozoic through the early Paleozoic, coinciding with the decline of non-pelletal phosphorite deposits. Its temporal abundance during this timeframe makes it a particularly valuable window for the study of early animal evolution. Several occurrences of phosphatization from the Ediacaran through the Permian Period, including Doushantuo-type preservation of embryo-like fossils and acritarchs, phosphatized gut tracts within Burgess Shale-type carbonaceous compressions, Orsten-type preservation of meiofaunas, and other cases from the later Paleozoic are reviewed. In addition, a comprehensive description of the geochemical controls of calcium phosphate precipitation from seawater is provided, with a focus on the rates of phosphate nucleation and growth, favorable nucleation substrates, and properties of substrate tissue and pore-fluid chemistry. It is hoped that the paleontological and geochemical summaries provided here offer a practical and valuable guide to the Neoproterozoic–Paleozoic phosphatization window.
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15
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Cunningham JA, Vargas K, Marone F, Bengtson S, Donoghue PCJ. A multicellular organism with embedded cell clusters from the Ediacaran Weng'an biota (Doushantuo Formation, South China). Evol Dev 2017; 18:308-316. [PMID: 27870211 PMCID: PMC6849543 DOI: 10.1111/ede.12210] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Three‐dimensional analyses of the early Ediacaran microfossils from the Weng'an biota (Doushantuo Formation) have focused predominantly on multicellular forms that have been interpreted as embryos, and yet they have defied phylogenetic interpretation principally because of absence of evidence from other stages in their life cycle. It is therefore unfortunate that the affinities of the various other Doushantuo microfossils have been neglected. A new conical fossil that is preserved at a cellular level is described here. The fossil contains distinct cell clusters that are characterized and analysed in three dimensions. These clusters are often exposed at the specimen surface, and the fossil preserves many hemispherical craters that are interpreted as positions where clusters have left the organism. The cell clusters may be either reproductive propagules or infesting organisms. Similar clusters are found in a variety of Doushantuo organisms including putative animal embryos and algae.
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Affiliation(s)
- John A Cunningham
- Department of Palaeobiology and Nordic Center for Earth Evolution, Swedish Museum of Natural History, Stockholm 10405, Sweden.,School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, England
| | - Kelly Vargas
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, England
| | - Federica Marone
- Swiss Light Source, Paul Scherrer Institute, Villigen 5232, Switzerland
| | - Stefan Bengtson
- Department of Palaeobiology and Nordic Center for Earth Evolution, Swedish Museum of Natural History, Stockholm 10405, Sweden
| | - Philip C J Donoghue
- School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, England
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16
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Zong Y, Yao S, Lang J, Chen X, Fan J, Sun Z, Duan X, Li N, Fang H, Zhou G, Xiao T, Li A, Jiang H. Structural and compositional analysis of a casting mold sherd from ancient China. PLoS One 2017; 12:e0174057. [PMID: 28296963 PMCID: PMC5352019 DOI: 10.1371/journal.pone.0174057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 03/02/2017] [Indexed: 11/19/2022] Open
Abstract
Casting had symbolic significance and was strictly controlled in the Shang dynasty of ancient China. Vessel casting was mainly distributed around the Shang capital, Yin Ruins, which indicates a rigorous centralization of authority. Thus, for a casting mold to be excavated far from the capital region is rare. In addition to some bronze vessel molds excavated at the Buyao Village site, another key discovery of a bronze vessel mold occurred at Daxinzhuang. The Daxinzhuang site was a core area in the east of Shang state and is an important site to study the eastward expansion of the Shang. Here, combining synchrotron X-rays and other physicochemical analysis methods, nondestructive three-dimensional structure imaging and different elemental analyses were conducted on this mold sherd. Through high penetration X-ray tomography, we obtained insights on the internal structure and discovered some pores. We infer that the generation of pores inside the casting mold sherd was used to enhance air permeability during casting. Furthermore, we suppose that the decorative patterns on the surface were carved and not pasted onto it. Considering the previous compositional studies of bronze vessels, the copper and iron elements were analyzed by different methods. Unexpectedly, a larger amount of iron than of copper was detected on the surface. According to the data analysis and archaeological context, the source of iron on the casting mold sherd could be attributed to local soil contamination. A refined compositional analysis confirms that this casting mold was fabricated locally and used for bronze casting.
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Affiliation(s)
- Yunbing Zong
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, China
| | - Shengkun Yao
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Jianfeng Lang
- Department of Archaeology, Shandong University, Jinan, Shandong, China
| | - Xuexiang Chen
- Department of Archaeology, Shandong University, Jinan, Shandong, China
| | - Jiadong Fan
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Zhibin Sun
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, China
| | - Xiulan Duan
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, China
| | - Nannan Li
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, China
| | - Hui Fang
- Department of Archaeology, Shandong University, Jinan, Shandong, China
| | - Guangzhao Zhou
- S hanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China
| | - Tiqiao Xiao
- S hanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China
| | - Aiguo Li
- S hanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China
| | - Huaidong Jiang
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
- * E-mail:
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17
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Zong Y, Yao S, Crawford GW, Fang H, Lang J, Fan J, Sun Z, Liu Y, Zhang J, Duan X, Zhou G, Xiao T, Luan F, Wang Q, Chen X, Jiang H. Selection for Oil Content During Soybean Domestication Revealed by X-Ray Tomography of Ancient Beans. Sci Rep 2017; 7:43595. [PMID: 28240321 PMCID: PMC5327410 DOI: 10.1038/srep43595] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 01/24/2017] [Indexed: 11/24/2022] Open
Abstract
When and under what circumstances domestication related traits evolved in soybean (Glycine max) is not well understood. Seed size has been a focus of archaeological attention because increased soybean seed weight/size is a trait that distinguishes most modern soybeans from their ancestors; however, archaeological seed size analysis has had limited success. Modern domesticated soybean has a significantly higher oil content than its wild counterpart so oil content is potentially a source of new insight into soybean domestication. We investigated soybean oil content using X-ray computed tomography (CT; specifically, synchrotron radiation X-ray CT or SRX-CT) of charred, archaeological soybean seeds. CT identified holes in the specimens that are associated with oil content. A high oil content facilitates the development of small holes, whereas a high protein content results in larger holes. The volume of small holes increased slowly from 7,500 to 4,000 cal B.P. We infer that human selection for higher oil content began as early as 7,500 cal B.P. and that high oil content cultivars were well established by 4,000 cal B.P.
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Affiliation(s)
- Yunbing Zong
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Shengkun Yao
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Gary W. Crawford
- Department of Anthropology, University of Toronto Mississauga, Mississauga, Ontario, L5L 1C6, Canada
| | - Hui Fang
- Department of Archaeology, Shandong University, Jinan, Shandong 250100, China
| | - Jianfeng Lang
- Department of Archaeology, Shandong University, Jinan, Shandong 250100, China
| | - Jiadong Fan
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zhibin Sun
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Yang Liu
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Jianhua Zhang
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Xiulan Duan
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
| | - Guangzhao Zhou
- Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Tiqiao Xiao
- Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Fengshi Luan
- Department of Archaeology, Shandong University, Jinan, Shandong 250100, China
| | - Qing Wang
- Department of Archaeology, Shandong University, Jinan, Shandong 250100, China
| | - Xuexiang Chen
- Department of Archaeology, Shandong University, Jinan, Shandong 250100, China
| | - Huaidong Jiang
- State Key Laboratory of Crystal Materials, Shandong University, Jinan, Shandong 250100, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
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18
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Osés GL, Petri S, Becker-Kerber B, Romero GR, Rizzutto MDA, Rodrigues F, Galante D, da Silva TF, Curado JF, Rangel EC, Ribeiro RP, Pacheco MLAF. Deciphering the preservation of fossil insects: a case study from the Crato Member, Early Cretaceous of Brazil. PeerJ 2016; 4:e2756. [PMID: 28028459 PMCID: PMC5180586 DOI: 10.7717/peerj.2756] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/04/2016] [Indexed: 11/21/2022] Open
Abstract
Exceptionally well-preserved three-dimensional insects with fine details and even labile tissues are ubiquitous in the Crato Member Konservat Lagerstätte (northeastern Brazil). Here we investigate the preservational pathways which yielded such specimens. We employed high resolution techniques (EDXRF, SR-SXS, SEM, EDS, micro Raman, and PIXE) to understand their fossilisation on mineralogical and geochemical grounds. Pseudomorphs of framboidal pyrite, the dominant fossil microfabric, display size variation when comparing cuticle with inner areas or soft tissues, which we interpret as the result of the balance between ion diffusion rates and nucleation rates of pyrite through the originally decaying carcasses. Furthermore, the mineral fabrics are associated with structures that can be the remains of extracellular polymeric substances (EPS). Geochemical data also point to a concentration of Fe, Zn, and Cu in the fossils in comparison to the embedding rock. Therefore, we consider that biofilms of sulphate reducing bacteria (SRB) had a central role in insect decay and mineralisation. Therefore, we shed light on exceptional preservation of fossils by pyritisation in a Cretaceous limestone lacustrine palaeoenvironment.
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Affiliation(s)
- Gabriel Ladeira Osés
- Programa de Pós-graduação em Geoquímica e Geotectônica, Institute of Geosciences, Universidade de São Paulo , São Paulo , Brazil
| | - Setembrino Petri
- Institute of Geosciences, Universidade de São Paulo , São Paulo , Brazil
| | - Bruno Becker-Kerber
- Programa de Pós-Graduação em Ecologia e Recursos Naturais, Universidade Federal de São Carlos , São Carlos , São Paulo , Brazil
| | | | | | - Fabio Rodrigues
- Department of Fundamental Chemistry/Institute of Chemistry, Universidade de São Paulo , São Paulo , Brazil
| | | | | | - Jessica F Curado
- Department of Physics, Centro Universitário FEI , São Bernardo do Campo , Brazil
| | | | - Rafael Parra Ribeiro
- Laboratory of Technological Plasmas, Universidade Estadual Paulista , Sorocaba , Brazil
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19
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Cunningham JA, Liu AG, Bengtson S, Donoghue PCJ. The origin of animals: Can molecular clocks and the fossil record be reconciled? Bioessays 2016; 39:1-12. [PMID: 27918074 DOI: 10.1002/bies.201600120] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The evolutionary emergence of animals is one of the most significant episodes in the history of life, but its timing remains poorly constrained. Molecular clocks estimate that animals originated and began diversifying over 100 million years before the first definitive metazoan fossil evidence in the Cambrian. However, closer inspection reveals that clock estimates and the fossil record are less divergent than is often claimed. Modern clock analyses do not predict the presence of the crown-representatives of most animal phyla in the Neoproterozoic. Furthermore, despite challenges provided by incomplete preservation, a paucity of phylogenetically informative characters, and uncertain expectations of the anatomy of early animals, a number of Neoproterozoic fossils can reasonably be interpreted as metazoans. A considerable discrepancy remains, but much of this can be explained by the limited preservation potential of early metazoans and the difficulties associated with their identification in the fossil record. Critical assessment of both records may permit better resolution of the tempo and mode of early animal evolution.
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Affiliation(s)
- John A Cunningham
- School of Earth Sciences, University of Bristol, Bristol, UK.,Department of Palaeobiology and Nordic Center for Earth Evolution, Swedish Museum of Natural History, Stockholm, Sweden
| | - Alexander G Liu
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - Stefan Bengtson
- Department of Palaeobiology and Nordic Center for Earth Evolution, Swedish Museum of Natural History, Stockholm, Sweden
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20
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Opitz JM. Annals of morphologyTHEODOR BOVERI (1862-1915) To commemorate the centenary of his death and contributions to the Sutton-Boveri hypothesis. Am J Med Genet A 2016. [DOI: 10.1002/ajmg.a.37693] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- John M. Opitz
- Departments of Pediatrics (Medical Genetics), Pathology, Human Genetics, Obstetrics, and Gynecology; University of Utah School of Medicine; Salt Lake City Utah
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21
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Wray GA. Molecular clocks and the early evolution of metazoan nervous systems. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2015.0046. [PMID: 26554040 DOI: 10.1098/rstb.2015.0046] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The timing of early animal evolution remains poorly resolved, yet remains critical for understanding nervous system evolution. Methods for estimating divergence times from sequence data have improved considerably, providing a more refined understanding of key divergences. The best molecular estimates point to the origin of metazoans and bilaterians tens to hundreds of millions of years earlier than their first appearances in the fossil record. Both the molecular and fossil records are compatible, however, with the possibility of tiny, unskeletonized, low energy budget animals during the Proterozoic that had planktonic, benthic, or meiofaunal lifestyles. Such animals would likely have had relatively simple nervous systems equipped primarily to detect food, avoid inhospitable environments and locate mates. The appearance of the first macropredators during the Cambrian would have changed the selective landscape dramatically, likely driving the evolution of complex sense organs, sophisticated sensory processing systems, and diverse effector systems involved in capturing prey and avoiding predation.
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Affiliation(s)
- Gregory A Wray
- Department of Biology and Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
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22
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Zhang Q, Zhang W. Regulation of developmental and environmental signaling by interaction between microtubules and membranes in plant cells. Protein Cell 2016; 7:81-8. [PMID: 26687389 PMCID: PMC4742386 DOI: 10.1007/s13238-015-0233-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 10/31/2015] [Indexed: 12/16/2022] Open
Abstract
Cell division and expansion require the ordered arrangement of microtubules, which are subject to spatial and temporal modifications by developmental and environmental factors. Understanding how signals translate to changes in cortical microtubule organization is of fundamental importance. A defining feature of the cortical microtubule array is its association with the plasma membrane; modules of the plasma membrane are thought to play important roles in the mediation of microtubule organization. In this review, we highlight advances in research on the regulation of cortical microtubule organization by membrane-associated and membrane-tethered proteins and lipids in response to phytohormones and stress. The transmembrane kinase receptor Rho-like guanosine triphosphatase, phospholipase D, phosphatidic acid, and phosphoinositides are discussed with a focus on their roles in microtubule organization.
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Affiliation(s)
- Qun Zhang
- College of Life Sciences, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Wenhua Zhang
- College of Life Sciences, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China.
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23
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Reconstructing the reproductive mode of an Ediacaran macro-organism. Nature 2015; 524:343-6. [PMID: 26237408 DOI: 10.1038/nature14646] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 06/08/2015] [Indexed: 11/08/2022]
Abstract
Enigmatic macrofossils of late Ediacaran age (580-541 million years ago) provide the oldest known record of diverse complex organisms on Earth, lying between the microbially dominated ecosystems of the Proterozoic and the Cambrian emergence of the modern biosphere. Among the oldest and most enigmatic of these macrofossils are the Rangeomorpha, a group characterized by modular, self-similar branching and a sessile benthic habit. Localized occurrences of large in situ fossilized rangeomorph populations allow fundamental aspects of their biology to be resolved using spatial point process techniques. Here we use such techniques to identify recurrent clustering patterns in the rangeomorph Fractofusus, revealing a complex life history of multigenerational, stolon-like asexual reproduction, interspersed with dispersal by waterborne propagules. Ecologically, such a habit would have allowed both for the rapid colonization of a localized area and for transport to new, previously uncolonized areas. The capacity of Fractofusus to derive adult morphology by two distinct reproductive modes documents the sophistication of its underlying developmental biology.
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24
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Sponge grade body fossil with cellular resolution dating 60 Myr before the Cambrian. Proc Natl Acad Sci U S A 2015; 112:E1453-60. [PMID: 25775601 DOI: 10.1073/pnas.1414577112] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
An extraordinarily well preserved, 600-million-year (Myr)-old, three-dimensionally phosphatized fossil displaying multiple independent characters of modern adult sponges has been analyzed by SEM and synchrotron X-ray tomography. The fossilized animal (Eocyathispongia qiania gen. et sp. nov.) is slightly more than 1.2 mm wide and 1.1 mm tall, is composed of hundreds of thousands of cells, and has a gross structure consisting of three adjacent hollow tubes sharing a common base. The main tube is crowned with a large open funnel, and the others end in osculum-like openings to the exterior. The external surface is densely covered with flat tile-like cells closely resembling sponge pinacocytes, and this layer is punctuated with smaller pores. A dense patch of external structures that display the form of a lawn of sponge papillae has also survived. Within the main funnel, an area where features of the inner surface are preserved displays a regular pattern of uniform pits. Many of them are surrounded individually by distinct collars, mounted in a supporting reticulum. The possibility cannot be excluded that these pits are the remains of a field of choanocytes. The character set evinced by this specimen, ranging from general anatomy to cell type, uniquely indicates that this specimen is a fossil of probable poriferan affinity. So far, we have only this single specimen, and although its organized and complex cellular structure precludes any reasonable interpretation that its origin is abiogenic, confirmation that it is indeed a fossilized sponge will clearly require discovery of additional specimens.
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25
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Abstract
Microtubules (MTs) are highly conserved polar polymers that are key elements of the eukaryotic cytoskeleton and are essential for various cell functions. αβ-tubulin, a heterodimer containing one structural GTP and one hydrolysable and exchangeable GTP, is the building block of MTs and is formed by the sequential action of several molecular chaperones. GTP hydrolysis in the MT lattice is mechanistically coupled with MT growth, thus giving MTs a metastable and dynamic nature. MTs adopt several distinct higher-order organizations that function in cell division and cell morphogenesis. Small molecular weight compounds that bind tubulin are used as herbicides and as research tools to investigate MT functions in plant cells. The de novo formation of MTs in cells requires conserved γ-tubulin-containing complexes and targeting/activating regulatory proteins that contribute to the geometry of MT arrays. Various MT regulators and tubulin modifications control the dynamics and organization of MTs throughout the cell cycle and in response to developmental and environmental cues. Signaling pathways that converge on the regulation of versatile MT functions are being characterized.
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Affiliation(s)
- Takashi Hashimoto
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara 630-0192, Japan
- Address correspondence to
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26
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Dai X, Zhang Y, Zhang D, Chen J, Gao X, Estelle M, Zhao Y. Embryonic lethality of Arabidopsis abp1-1 is caused by deletion of the adjacent BSM gene. NATURE PLANTS 2015; 1:15183. [PMID: 27057346 PMCID: PMC4821195 DOI: 10.1038/nplants.2015.183] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 10/21/2015] [Indexed: 05/22/2023]
Abstract
Decades of research have suggested that AUXIN BINDING PROTEIN 1 (ABP1) is an essential membrane-associated auxin receptor, but recent findings directly contradict this view. Here we show that embryonic lethality observed in abp1-1, which has been a cornerstone of ABP1 studies, is caused by the deletion of the neighbouring BELAYA SMERT (BSM) gene, not by disruption of ABP1. On the basis of our results, we conclude that ABP1 is not essential for Arabidopsis development.
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Affiliation(s)
- Xinhua Dai
- Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0116, USA
| | - Yi Zhang
- Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0116, USA
- Howard Hughes Medical Institute, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0116, USA
| | - Da Zhang
- Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0116, USA
- College of Life Sciences, Northeast Agricultural University, Harbin 150030, China
| | - Jilin Chen
- Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0116, USA
- College of Life Sciences, Xiamen University, Xiang An Nan Road, Xiamen 361102, Fujian Province, China
| | - Xiuhua Gao
- Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0116, USA
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 1 West Beichan Road, Beijing 100101, China
| | - Mark Estelle
- Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0116, USA
- Howard Hughes Medical Institute, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0116, USA
| | - Yunde Zhao
- Section of Cell and Developmental Biology, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0116, USA
- Correspondence and requests for materials should be addressed to Y. Zhao.
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