Evidência de colágeno preservado em fóssil de dinossauro do Jurássico Inferior (195 milhões de anos)

terça-feira, janeiro 31, 2017

Evidence of preserved collagen in an Early Jurassic sauropodomorph dinosaur revealed by synchrotron FTIR microspectroscopy

Yao-Chang Lee, Cheng-Cheng Chiang, Pei-Yu Huang, Chao-Yu Chung, Timothy D. Huang, Chun-Chieh Wang, Ching-Iue Chen, Rong-Seng Chang, Cheng-Hao Liao & Robert R. Reisz

Nature Communications 8, Article number: 14220 (2017)


Received: 13 December 2015 Accepted: 09 December 2016 Published online: 
31 January 2017

Figure 1: Rib fragment (CXPM Z4644) of Lufengosaurus.


Fossilized organic remains are important sources of information because they provide a unique form of biological and evolutionary information, and have the long-term potential for genomic explorations. Here we report evidence of protein preservation in a terrestrial vertebrate found inside the vascular canals of a rib of a 195-million-year-old sauropodomorph dinosaur, where blood vessels and nerves would normally have been present in the living organism. The in situ synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectra exhibit the characteristic infrared absorption bands for amide A and B, amide I, II and III of collagen. Aggregated haematite particles (α-Fe2O3) about 6∼8 μm in diameter are also identified inside the vascular canals using confocal Raman microscopy, where the organic remains were preserved. We propose that these particles likely had a crucial role in the preservation of the proteins, and may be remnants partially contributed from haemoglobin and other iron-rich proteins from the original blood.


We thank ChuanWei Yang of LuFeng County Dinosaur Museum and ShiMing Zhong of ChuXiong Prefecture Museum for their assistance in field work, and Cheng-Chi Chen for help with SR-FTIR experiments and the colleagues in the accelerator operation group at the NSRRC, Taiwan, for optimizing the stability of the infrared synchrotron radiation. Funding was provided by NSRRC, MOE 103G-903-2 through National Central University, MOST 105-2112-M-213-001 (Taiwan) and NSERC (Canada).

Author information


National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan

Yao-Chang Lee, Cheng-Cheng Chiang, Pei-Yu Huang, Chun-Chieh Wang & Ching-Iue Chen

Department of Optics and Photonics, National Central University, Chung-Li 32001, Taiwan

Yao-Chang Lee, Timothy D. Huang, Rong-Seng Chang & Robert R. Reisz

Department of Applied Chemistry, National Chiao Tung University, Hsinchu 30010, Taiwan

Chao-Yu Chung

Dinosaur Evolution Research Center of Jilin University, Changchun, Jilin 130012, China

Timothy D. Huang & Robert R. Reisz

College of Life Sciences, National Chung Hsing University, Taichung 400, Taiwan

Timothy D. Huang & Robert R. Reisz

Tosun Public Interests Foundation, Taipei 100, Taiwan

Cheng-Hao Liao

Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada L5L 1C6

Robert R. Reisz


Y.-C.L. wrote first draft of the paper, analysed spectral data of SR-FTIR and Raman scattering and constructed SR-FTIR spectral images. C.-C.C. made fossil ultrathin slides; C.-C.C. and R.-S.C. first found red-blood-cell-like particles within the Lufengosaurus rib and proposed their study. P.-Y.H. acquired FTIR spectral data and constructed FTIR images; C.-Y.C. collected the transient absorption images of haematite in the fossil; T.D.H. initiated the organic remains project, provided various fossil specimens and contributed to the manuscript. C.-C.W. helped to acquire three-dimensional tomographic images. C.-I.C. set optical alignment of endstation of IMS and acquired FTIR spectral images; C.-H.L. provided logistical and research support. R.R.R. proposed the study, contributed to manuscript and guided the project.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Yao-Chang Lee or Robert R. Reisz.

Novo fóssil do Cambriano, excepcionalmente preservado, lança luz sobre a vida na Terra

Exceptionally preserved Cambrian loriciferans and the early animal invasion of the meiobenthos

Thomas H. P. Harvey & Nicholas J. Butterfield

Nature Ecology & Evolution 1, Article number: 0022 (2017)

Palaeoecology Palaeontology

Received: 25 May 2016 Accepted: 25 October 2016 Published online: 30 January 2017

Figure 1: E. deadwoodensis, a fossil loriciferan from the upper 
Cambrian Deadwood Formation of Canada.


Microscopic animals that live among and between sediment grains (meiobenthic metazoans) are key constituents of modern aquatic ecosystems, but are effectively absent from the fossil record. We describe an assemblage of microscopic fossil loriciferans (Ecdysozoa, Loricifera) from the late Cambrian Deadwood Formation of western Canada. The fossils share a characteristic head structure and minute adult body size (~300 μm) with modern loriciferans, indicating the early evolution and subsequent conservation of an obligate, permanently meiobenthic lifestyle. The unsuspected fossilization potential of such small animals in marine mudstones offers a new search image for the earliest ecdysozoans and other animals, although the anatomical complexity of loriciferans points to their evolutionary miniaturization from a larger-bodied ancestor. The invasion of animals into ecospace that was previously monopolized by protists will have contributed considerably to the revolutionary geobiological feedbacks of the Proterozoic/Phanerozoic transition.

Animals with minute body size are among the most abundant and diverse organisms in the marine benthos 1 , but most meiobenthic (or meiofaunal) animal lineages are palaeontologically invisible. Instead, inferences on the origins of microscopic body size rely on molecular phylogenetic analyses 2,3 and many groups remain poorly sampled or difficult to place in the tree of life. As such, there are conflicting predictions of ancestral body size for the major metazoan clades, with important implications for addressing the marked discordance between their first unequivocal fossil appearances in the terminal Ediacaran and Cambrian periods, and predictions from molecular clocks of early (or pre-) Ediacaran divergence dates 4,5 . Certainly, biases in the conventional fossil record leave open the possibility that the Cambrian explosion might artefactually conflate ecological and phylogenetic innovations by recording mostly macroscopic animals and their activities 6 . Here, we describe exceptionally preserved fossils demonstrating that microscopic loriciferans—a key lineage of meiobenthic ecdysozoans—had arisen by at least the late Cambrian. In addition to establishing a unique stratigraphic calibration point for this recently recognized phylum, these fossils provide important constraints on functional and phylogenetic models of early animal evolution.


We thank staff at the Geological Subsurface Laboratory, Regina, Saskatchewan, and M. Vélez, University of Regina, for help with core sampling. We thank geoLOGIC for generous access to subsurface data. This work was supported by Natural Environment Research Council Grant NE/H009914/1.

Author information


Department of Geology, University of Leicester, University Road, Leicester LE1 7RH, UK

Thomas H. P. Harvey

Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK

Nicholas J. Butterfield


T.H.P.H. and N.J.B. designed and performed the research and wrote the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Thomas H. P. Harvey.

Meteoritos raros comuns no período Ordoviciano (460 milhões de anos)

domingo, janeiro 29, 2017

Rare meteorites common in the Ordovician period

Philipp R. Heck, Birger Schmitz, William F. Bottke, Surya S. Rout, Noriko T. Kita, Anders Cronholm, Céline Defouilloy, Andrei Dronov & Fredrik Terfelt

Nature Astronomy 1, Article number: 0035 (2017)

Asteroids, comets and Kuiper belt Meteoritics

Received: 27 July 2016 Accepted: 14 December 2016 Published online: 23 January 2017

Source/Fonte: Lund University


Most meteorites that fall today are H and L type ordinary chondrites, yet the main belt asteroids best positioned to deliver meteorites are LL chondrites 1,2 . This suggests that the current meteorite flux is dominated by fragments from recent asteroid breakup events 3,4 and therefore is not representative over longer (100-Myr) timescales. Here we present the first reconstruction of the composition of the background meteorite flux to Earth on such timescales. From limestone that formed about one million years before the breakup of the L-chondrite parent body 466 Myr ago, we have recovered relict minerals from coarse micrometeorites. By elemental and oxygen-isotopic analyses, we show that before 466 Myr ago, achondrites from different asteroidal sources had similar or higher abundances than ordinary chondrites. The primitive achondrites, such as lodranites and acapulcoites, together with related ungrouped achondrites, made up ~15–34% of the flux compared with only ~0.45% today. Another group of abundant achondrites may be linked to a 500-km cratering event on (4) Vesta that filled the inner main belt with basaltic fragments a billion years ago 5 . Our data show that the meteorite flux has varied over geological time as asteroid disruptions create new fragment populations that then slowly fade away from collisional and dynamical evolution. The current flux favours disruption events that are larger, younger and/or highly efficient at delivering material to Earth.

To investigate the past meteorite flux, we searched for relict chrome-spinel grains of coarse micrometeorites in condensed marine sediments in northwestern Russia, in a time window of ~10–100 kyr in the geological epoch of the Middle Ordovician period, which ranges from 470 to 458 Myr ago (Fig. 1; see Methods). Chrome spinels are the only minerals of meteorites and coarse micrometeorites that survived diagenesis in Ordovician limestone 6 . They retained their elemental and oxygen isotopic composition, enabling reliable classification based on single-grain microanalysis 7,8 . We also dissolved 32 meteorites of different types in HF or HCl acid to quantify their content of chrome-spinel grains. The sediment sample that we studied is about a million years older than the ~466-Myr-old sediments that contain the first collisional fragments from the L-chondrite parent body breakup (LCPB), the largest known asteroid disruption event in the past three billion years. The sampling level was chosen to exclude the extreme flux enhancement (more than two orders of magnitude 6,7 ) of L-chondritic fragments after the LCPB that obscures the background flux for more than 1 Myr (refs 7,​8,​9 ). The low, 50- to 100-kyr, cosmic-ray exposure ages of the oldest recovered fossil L chondrites 9 imply that any fragments from the LCPB that might have arrived on Earth before should have even shorter exposure ages. This indicates that a sample separation of one million years before the strata containing the first ­abundant L chondrites is large enough to assess the pre-LCPB flux. The ­interval sampled represents a time average of about 10 to 100 kyr and was selected with the aim of determining whether the ­composition of the meteorite flux to Earth was similar to or different from that of today. This is the first reconstruction of the background flux of the different meteorite types in a geological time perspective. Similar reconstructions are ongoing for other periods in the Earth’s ­geological past 10 .

Additional information

How to cite this article: Heck, P. R. et al. Rare meteorites common in the Ordovician period. Nat. Astron. 1, 0035 (2017).


The study was supported by an ERC-Advanced Grant (ASTROGEOBIOSPHERE) to B.S. P.R.H. acknowledges funding from the Tawani Foundation. A.D. acknowledges support from the Russian Governmental Program of Competitive Growth of Kazan Federal University and RFBR (grant 16-05-00799). W.F.B’s participation was supported by NASA’s SSERVI program “Institute for the Science of Exploration Targets (ISET)” through institute grant number NNA14AB03A. We thank K. Deppert and P. Eriksson for support at Lund University, F. Iqbal for the laboratory work, and B. Strack for maintenance of the Field Museum’s SEM laboratory. WiscSIMS is partly supported by the National Science Foundation (EAR03-19230, EAR13-55590). We thank J. Kern for SIMS support. The 3D microscopy was performed in the Keck-II facility of the Northwestern University NUANCE Center, supported by NSEC (NSF EEC–0647560), MRSEC (NSF DMR-1121262), the Keck Foundation, the State of Illinois and Northwestern University.

Author information


Robert A. Pritzker Center for Meteoritics and Polar Studies, The Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, Illinois 60605, USA

Philipp R. Heck, Birger Schmitz & Surya S. Rout

Chicago Center for Cosmochemistry and Department of the Geophysical Sciences, The University of Chicago, 5734 South Ellis Avenue, Chicago, Illinois 60637, USA

Philipp R. Heck & Surya S. Rout

Astrogeobiology Laboratory, Department of Physics, Lund University, PO Box 118, SE-22100 Lund, Sweden

Birger Schmitz, Anders Cronholm & Fredrik Terfelt

Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, Colorado 80302, USA

William F. Bottke

WiscSIMS, Department of Geoscience, University of Wisconsin-Madison, 1215 W. Dayton Street, Madison, Wisconsin 53706-1692, USA

Noriko T. Kita & Céline Defouilloy

Geological Institute, Russian Academy of Sciences, Pyzhevsky Pereulok 7, 119017 Moscow, Russia

Andrei Dronov

Kazan (Volga Region) Federal University, Kremlevskaya ulitsa 18, 420008 Kazan, Russia

Andrei Dronov


P.R.H. and B.S. conceived the study and wrote the paper with input from all authors. W.F.B. provided expertise on the collisional and dynamical evolution of the asteroid belt and meteoroid delivery models. B.S., F.T. and A.D. conducted the fieldwork. B.S., F.T. and A.C. extracted and prepared the samples for SEM/EDS and SIMS. A.C. performed the quantitative SEM/EDS analysis. P.R.H. and S.S.R. prepared the samples for SIMS and performed the SIMS and post-SIMS analyses. N.T.K. and C.D. set up SIMS analysis conditions and assisted with the analyses.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Philipp R. Heck.

FREE PDF GRATIS: Nature Astronomy Sup. Info.

PDF files

1. Supplementary Information Supplementary Figures 1 and 2, Supplementary Table 1, description of Supplementary Data files.

Excel files

1. Supplementary DataData table with Δ17O, TiO2 and V2O3 values and classification of fossil micrometeorites.

2. Supplementary DataChrome spinel abundances in different types of meteorites.

3. Supplementary DataReference data.

4. Supplementary DataFull data table with O-isotopic SIMS data and quantitative elemental EDS data.

Descoberto primeiro fóssil de trilobita com ovos de 450 milhões de anos

Pyritized in situ trilobite eggs from the Ordovician of New York (Lorraine Group): Implications for trilobite reproductive biology

Thomas A. Hegna1, Markus J. Martin2 and Simon A.F. Darroch3

- Author Affiliations

1Department of Geology, Western Illinois University, 113 Tillman Hall, 1 University Circle, Macomb, Illinois 61455, USA

2371 Pawling Street, Watertown, New York 13601, USA

3Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, Tennessee 37235, USA

Source/Fonte: Sciency Thoughts blog


Despite a plethora of exceptionally preserved trilobites, trilobite reproduction has remained a mystery. No previously described trilobite has unambiguous eggs or genitalia preserved. This study reports the first occurrence of in situ preserved eggs belonging to Triarthrus eatoni (Hall, 1838) trilobites from the Lorraine Group in upstate New York, USA. Like other exceptionally preserved trilobites from the Lorraine Group, the complete exoskeletons are replaced with pyrite. The eggs are spherical to elliptical in shape, nearly 200 μm in size, and are clustered in the genal area of the cephalon. The fact that the eggs are smaller than the earliest-known trilobite ontogenetic (protaspis) stage suggests that trilobites may have had an unmineralized preliminary stage in their ontogeny, and that the protaspis shield formed only after hatching. The eggs are only visible ventrally with no dorsal brood pouch or recognized sexual dimorphism. The location of the eggs is consistent with where modern female horseshoe crabs release their unfertilized eggs from the ovarian network within their head. Trilobites likely released their gametes (eggs and sperm) through a genital pore of as-yet unknown location (likely near the posterior boundary of the head). If the T. eatoni reproductive biology is representative of other trilobites, they spawned with external fertilization, possibly the ancestral mode of reproduction for early arthropods. Because pyritization preferentially preserves the external rather than internal features of fossils, it is suggested that there is likely a bias in the fossil record toward the preservation of arthropods that brood eggs externally: arthropods that brood their eggs internally are unlikely to preserve any evidence of their mode of reproduction.

Received 18 July 2016. Revision received 7 November 2016. Accepted 8 November 2016.

© Geological Society of America


"Guarda de trânsito" regulador: proteína controla velocidade do emparelhamento dos cromossomos e compartilhamento do DNA

sábado, janeiro 28, 2017

Regulating chromosomal movement by the cochaperone FKB-6 ensures timely pairing and synapsis

Benjamin Alleva, Nathan Balukoff, Amy Peiper, Sarit Smolikove

DOI: 10.1083/jcb.201606126 | Published January 11, 2017


In meiotic prophase I, homologous chromosome pairing is promoted through chromosome movement mediated by nuclear envelope proteins, microtubules, and dynein. After proper homologue pairing has been established, the synaptonemal complex (SC) assembles along the paired homologues, stabilizing their interaction and allowing for crossing over to occur. Previous studies have shown that perturbing chromosome movement leads to pairing defects and SC polycomplex formation. We show that FKB-6 plays a role in SC assembly and is required for timely pairing and proper double-strand break repair kinetics. FKB-6 localizes outside the nucleus, and in its absence, the microtubule network is altered. FKB-6 is required for proper movement of dynein, increasing resting time between movements. Attenuating chromosomal movement in fkb-6 mutants partially restores the defects in synapsis, in agreement with FKB-6 acting by decreasing chromosomal movement. Therefore, we suggest that FKB-6 plays a role in regulating dynein movement by preventing excess chromosome movement, which is essential for proper SC assembly and homologous chromosome pairing.

Submitted: 28 June 2016 Revision received 7 November 2016 Accepted: 29 December 2016

This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms/). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 International license, as described at https://creativecommons.org/licenses/by-nc-sa/4.0/).


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Mero acaso, fortuita necessidade ou design inteligente???

Primeira quimera humano-porcino via células-tronco pluripotentes???

sexta-feira, janeiro 27, 2017

Interspecies Chimerism with Mammalian Pluripotent Stem Cells

Jun Wu, Aida Platero-Luengo, Masahiro Sakurai, Atsushi Sugawara, Maria Antonia Gil, Takayoshi Yamauchi, Keiichiro Suzuki, Yanina Soledad Bogliotti, Cristina Cuello, Mariana Morales Valencia, Daiji Okumura7, Jingping Luo, Marcela Vilariño, Inmaculada Parrilla, Delia Alba Soto, Cristina A. Martinez, Tomoaki Hishida, Sonia Sánchez-Bautista, M. Llanos Martinez-Martinez, Huili Wang, Alicia Nohalez, Emi Aizawa, Paloma Martinez-Redondo, Alejandro Ocampo, Pradeep Reddy, Jordi Roca, Elizabeth A. Maga, Concepcion Rodriguez Esteban, W. Travis Berggren, Estrella Nuñez Delicado, Jeronimo Lajara, Isabel Guillen, Pedro Guillen, Josep M. Campistol, Emilio A. Martinez, Pablo Juan Ross, Juan Carlos Izpisua Belmonte8.

7Present address: Graduate School of Agriculture, Department of Advanced Bioscience, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan

8Lead Contact


• Naive rat PSCs robustly contribute to live rat-mouse chimeras

• A versatile CRISPR-Cas9 mediated interspecies blastocyst complementation system

• Naive rodent PSCs show no chimeric contribution to post-implantation pig embryos

• Chimerism is observed with some human iPSCs in post-implantation pig embryos


Interspecies blastocyst complementation enables organ-specific enrichment of xenogenic pluripotent stem cell (PSC) derivatives. Here, we establish a versatile blastocyst complementation platform based on CRISPR-Cas9-mediated zygote genome editing and show enrichment of rat PSC-derivatives in several tissues of gene-edited organogenesis-disabled mice. Besides gaining insights into species evolution, embryogenesis, and human disease, interspecies blastocyst complementation might allow human organ generation in animals whose organ size, anatomy, and physiology are closer to humans. To date, however, whether human PSCs (hPSCs) can contribute to chimera formation in non-rodent species remains unknown. We systematically evaluate the chimeric competency of several types of hPSCs using a more diversified clade of mammals, the ungulates. We find that naïve hPSCs robustly engraft in both pig and cattle pre-implantation blastocysts but show limited contribution to post-implantation pig embryos. Instead, an intermediate hPSC type exhibits higher degree of chimerism and is able to generate differentiated progenies in post-implantation pig embryos.

Author Contributions

J.W. and J.C.I.B. conceived the study. J.W. generated and characterized all naive and intermediate hiPSC lines. K.S. generated and characterized primed hiPSCs. J.W. and T.H. generated rat iPSCs. J.W., A.P.-L., T.Y., M.M.V., D.O., A.O., P.R., C.R.E., J.W., and P.M.R. performed immunohistochemistry analyses of mouse and pig embryos. K.S., T.Y., E.S., A.P.-L., and M.M.V. performed genotyping, genomic PCR, and genomic qPCR analyses. A.S., M.S., and J.P.L. performed mouse Cas9/sgRNA injection, blastocyst injection, and embryo transfer. Y.S.B., M.S., and M.V. prepared hiPSCs, performed morulae and blastocyst injections, and analyzed hiPSC contribution to cattle and ppig ICMs. H.W. produced parthenogenetic pig embryos. D.A.S., Y.S.B., and M.V. produced cattle embryos. Work at UC Davis and University of Murcia was performed under the supervision of P.J.R. and E.A.M., respectively. E.A.M., M.A.G., C.C., I.P., C.A.M., S.S.B., A.N., and J.R. designed, coordinated, performed, and analyzed data related to pig embryo collection, embryo culture, blastocyst injection, embryo transfer, and embryo recover. E.N.D., J.L., I.G., P.G., T.B., M.L.M.-M., and J.M.C. coordinated work between Salk, and University of Murcia. J.W., P.J.R., and J.C.I.B. wrote the manuscript.


J.C.I.B. dedicates this paper to Dr. Rafael Matesanz, Director of the Spain’s National Organ Transplant Organization. Rafael’s work has helped save thousands of patients in need of an organ. He constitutes a relentless inspiration for those of us trying to understand and alleviate human disease. The authors are grateful to Xiomara Lucas, Maria Dolores Ortega, Moises Gonzalvez, Jose Antonio Godinez, and Jesus Gomis for their assistance throughout this work. We thank the staff of the Agropor S.A. and Porcisan S.A. piggeries (Murcia, Spain) for the help and excellent management of animals. We thank Joan Rowe, Bret McNabb, Aaron Prinz, and Kent Parker and their crews for excellent assistance with embryo transfers and pig care at UC Davis. We thank Mako Yamamoto for help with mouse embryo dissection. We would like to thank Uri Manor of the Salk Waitt Advanced Biophotonics Core for technical advice on imaging analysis. We would like to thank the Salk Stem Cell Core for providing cell culture reagents. We would like to thank May Schwarz and Peter Schwarz for administrative help. We thank David O’Keefe for critical reading and editing of the manuscript. This experimental study was supported by The Fundación Séneca ( GERM 19892/GERM/15 ), Murcia, Spain. The MINECO is acknowledged for their grant-based support ( BES-2013-064087 and BES-2013-064069 ) (to C.A.M and A.N.). P.J.R was supported by a UC Davis Academic Senate New Research grant. Work in the laboratory of J.C.I.B. was supported by the UCAM, Fundacion Dr. Pedro Guillen, G. Harold and Leila Y. Mathers Charitable Foundation, and The Moxie Foundation.

FREE PDF GRATIS: Cell Supplemental Information 1, 2, 3, 4, 5, 6.



Os cientistas NÃO FUNDIRAM o DNA de um humano e um porco.

Eles apenas deixaram crescer um embrião de porco normal.

Depois eles injetaram um número "baixo" de células-tronco humanas no embrião de porco.

Eles então removeram as células-tronco humanas.

Após isso, não havia células que tinham uma mistura de DNA humano e de porco.

Eles NÃO DEMONSTRARAM a compatibi
lidade do DNA humano com o DNA de proco, e nem demonstraram ser o embrião de porco seria viável até o nascimento com as células humanas.

Tornando visível o invisível: primeira observação 3D de nanomáquinas funcionando dentro das células - mero acaso, fortuita necessidade ou design inteligente?

The In Vivo Architecture of the Exocyst Provides Structural Basis for Exocytosis

Andrea Picco5, Ibai Irastorza-Azcarate5, Tanja Specht, Dominik Böke, Irene Pazos, Anne-Sophie Rivier-Cordey, Damien P. Devos, Marko Kakson, Oriol Gallego6, 

5Co-first author

6Lead Contact

Article Info

Publication History

Published: January 26, 2017 Accepted: January 5, 2017 Received in revised form: October 18, 2016 Received: February 9, 2016


• An integrative approach reconstructs protein complexes in 3D through live-cell imaging

• We use this approach to reconstruct the exocyst complex bound to a vesicle in vivo

• Exocyst is a stable complex and regulatory proteins target its multimerization site

• We model how exocyst binds the vesicle allowing its contact with the plasma membrane


The structural characterization of protein complexes in their native environment is challenging but crucial for understanding the mechanisms that mediate cellular processes. We developed an integrative approach to reconstruct the 3D architecture of protein complexes in vivo. We applied this approach to the exocyst, a hetero-octameric complex of unknown structure that is thought to tether secretory vesicles during exocytosis with a poorly understood mechanism. We engineered yeast cells to anchor the exocyst on defined landmarks and determined the position of its subunit termini at nanometer precision using fluorescence microscopy. We then integrated these positions with the structural properties of the subunits to reconstruct the exocyst together with a vesicle bound to it. The exocyst has an open hand conformation made of rod-shaped subunits that are interlaced in the core. The exocyst architecture explains how the complex can tether secretory vesicles, placing them in direct contact with the plasma membrane.


Vesicle trafficking, exocytosis, exocyst, fluorescence microscopy, fluorescence localization, integrative structural biology, architecture of protein complexes, in vivo structure, PICT, SHREC.


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Imagens escaneadas em 3D de múmias expostas em espaços públicos

quinta-feira, janeiro 26, 2017

Interactive Visualization of 3D Scanned Mummies at Public Venues

By Anders Ynnerman, Thomas Rydell, Daniel Antoine, David Hughes, Anders Persson, Patric Ljung 

Communications of the ACM, Vol. 59 No. 12, Pages 72-81

Gebelein Man

By combining visualization techniques with interactive multi-touch tables and intuitive user interfaces, visitors to museums and science centers can conduct self-guided tours of large volumetric image data. In an interactive learning experience, visitors become the explorers of otherwise invisible interiors of unique artifacts and subjects. Here, we take as our starting point the state of the art in scanning technologies, then discuss the latest research on high-quality interactive volume rendering and how it can be tailored to meet the specific demands of public venues. We then describe our approach to the creation of interactive stories and the design principles on which they are based and interaction with domain experts. The article is based on experience from several application domains but uses a 2012 public installation of an ancient mummy at the British Museum as its primary example. We also present the results of an evaluation of the installation showing the utility of the developed solutions.

Visitors walk into Gallery 64, the Early Egypt Gallery at the British Museum, eager to see and learn about one of the most famous and oldest mummies in the collection. Known as the Gebelein Man, he was buried in a crouched position in a shallow grave during the late pre-dynastic period at the site of Gebelein in Upper Egypt. Unlike later Egyptian mummies, he was not artificially embalmed and his body was naturally mummified by the arid environment and direct contact with the hot dry sand more than 5,500 years ago. The mummy is safely protected behind glass and within a carefully controlled environment, beyond physical reach (see Figure 1). As visitors continue through the gallery a large touch-table display draws their attention. Gathered around the table are several other visitors gazing down at the glass screen.

The same mummy is shown on the surface of the table, but, as a visitor moves a virtual slider on the table, the muscles, organs, and skeleton reveal themselves as the skin is gradually peeled away. Another visitor turns the mummy around to explore the other side. Someone touches the information icon near the left shoulder blade to discover that the cut on his back, as well as the damaged underlying shoulder blade and fourth rib, are the result of a single penetrating wound. The history of the Gebelein Man unfolds for the visitor in the same way researchers have used visualization to establish the cause of death; the Gebelein Man was murdered, with a metal blade the most likely weapon.2

The technology allowing visitors to the British Museum to explore the Gebelein Man is an image-generation technique called "volume rendering" that is efficiently executed on graphics processing units (GPUs). A stack of thousands of 2D images, as generated by modern computed tomography (CT) X-ray scanners, is processed in parallel to interactively create images. During the past decade, various museums have begun to scan human remains and artifacts from their collections. Not only are mummies scanned, so too are meteorites, bee flies, gecko lizards embedded in amber, and much more in 3D; see a 2013 report from the Smithsonian Institution.4

This article describes the underlying research and development of algorithms and technologies that have become the basis for a software solution for multi-touch tables. It also describes how the workflow of scanning, curating, and integrating the data into the overall creation of stories for the public can lead to engaging installations at museums around the world. Our work is an example of how computing technologies, especially in computer graphics and visualization, allow a general audience to interact with and explore the very same data that only scientists and domain experts have previously been able to study. Figure 2 shows children exploring the Neswaiu mummy at the Mediterranean Museum in Stockholm.

FREE PDF GRATIS: Communications of the ACM

Todas as pesquisas da NASA Open Access online

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The National Aeronautics and Space Act of 1958 challenged our Nation to grow our technical and scientific abilities in air and space. Since the 1970s, numerous economic reports and articles have demonstrated that NASA investments help grow the US economy. Perhaps most importantly NASA-funded R&D helped stimulate our long-term capacity for innovation and economic growth within the government, at universities, and at industrial companies. The disciplines advanced are many – including earth and space science, materials, computing and electronics, fuels, radio communications, safety, and even human health.

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Konservat-Lagerstätte Ya Ha Tinda, período Jurássico (180 milhões de anos), Alberta, Canadá, contém fósseis com tecidos moles

A new Early Jurassic (ca. 183 Ma) fossil Lagerstätte from Ya Ha Tinda, Alberta, Canada

Rowan C. Martindale1,2, Theodore R. Them II3,4, Benjamin C. Gill3, Selva M. Marroquín1,3 and Andrew H. Knoll2

- Author Affiliations

1Department of Geological Sciences, The University of Texas at Austin, 1 University Station C1100, Austin, Texas 78712, USA

2Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, Massachusetts 02138, USA

3Department of Geosciences, Virginia Polytechnic Institute and State University, 4044 Derring Hall (0420), Blacksburg, Virginia 24061, USA

4Department of Earth, Ocean and Atmospheric Science & National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32306, USA

Figure 3. Exceptionally preserved fossils of Ya Ha Tinda Lagerstätte (Alberta, Canada; specimen numbers are provided in Data Repository [see footnote 1]). RDM—Red Deer Member; PCS—Poker Chip Shale Member.

A: Articulated ichthyosaur vertebrae and ribs (RDM, late Pliensbachian).

B: Skull of small teleost fish (PCS, within Toarcian Oceanic Anoxic Event [T-OAE] carbon isotope excursion [CIE]); note preservation of gills (arrow). C: Seirocrinus subangularis (crinoid) calyx collected by Russell Hall (RDM, late Pliensbachian). D: Vampyropod gladius with mantle muscle (white arrow) and ink sac (black arrow) (RDM, early Toarcian). E: Loligosepiid vampyropod gladius with ink sac (arrow) (RDM, early Toarcian). F: Shrimp body fossil (PCS, within T-OAE CIE). G: Complete body fossil of Uncina pacifica lobster, proximodistally flattened (RDM, late Pliensbachian). H: Complete body fossil of eryonid lobster, dorsoventrally flattened, ventral view (RDM, late Pliensbachian).


Lagerstätten—deposits of exceptionally preserved fossils—offer vital insights into evolutionary history. To date, only three Konservat-Lagerstätten are known from Early Jurassic marine rocks (Osteno, Posidonia Shale, and Strawberry Bank), all located in Europe. We report a new assemblage of exceptionally preserved fossils from Alberta, Canada, the first marine Konservat-Lagerstätte described from the Jurassic of North America. The Ya Ha Tinda assemblage includes articulated vertebrates (fish, ichthyosaurs), crinoids, crustaceans, brachiopods, abundant mollusks (coleoids with soft tissues, ammonites, gastropods, bivalves), wood, and microfossils. Paired bioand chemostratigraphies show that Lagerstätte deposition occurred during the late Pliensbachian through early Toarcian, capturing the carbon isotope excursion associated with the Toarcian Oceanic Anoxic Event. Therefore, the Panthalassan Ya Ha Tinda biota is coeval with Toarcian Lagerstätten from the Tethys Ocean (Posidonia Shale and Strawberry Bank). Comparisons among these deposits permit new insights into the diversity, ecology, and biogeography of Jurassic marine communities during a time of pronounced biological and environmental change (e.g., expanded subsurface anoxia, warming, and extinctions). They also highlight the possibility that Mesozoic Oceanic Anoxic Events are temporal foci of exceptional preservation.

Received 16 June 2016. Revision received 26 November 2016. Accepted 29 November 2016.

©The Authors

Gold Open Access: This paper is published under the terms of the CC-BY license.


Salvem a Árvore da vida de Darwin ou se percam nas matas da evolução neutra

quarta-feira, janeiro 25, 2017

Save the tree of life or get lost in the woods

Ruben E Valas and Philip E Bourne

Biology Direct20105:44

DOI: 10.1186/1745-6150-5-44 © Valas and Bourne; licensee BioMed Central Ltd. 2010

Received: 10 June 2010Accepted: 1 July 2010Published: 1 July 2010



The wealth of prokaryotic genomic data available has revealed that the histories of many genes are inconsistent, leading some to question the value of the tree of life hypothesis. It has been argued that a tree-like representation requires suppressing too much information, and that a more pluralistic approach is necessary for understanding prokaryotic evolution. We argue that trees may still be a useful representation for evolutionary histories in light of new data.


Genomic data alone can be highly misleading when trying to resolve the tree of life. We present evidence from protein abundance data sets that genomic conservation greatly underestimates functional conservation. Function follows more of a tree-like structure than genetic material, even in the presence of horizontal transfer. We argue that the tree of cells must be incorporated into any new synthesis in order to place horizontal transfers into their proper selective context. We also discuss the role data sources other than primary sequence can play in resolving the tree of cells.


The tree of life is alive, but not well. Construction of the tree of cells has been viewed as the end goal of the study of evolution, where in reality we need to consider it more of a starting point. We propose a duality where we must consider variation of genetic material in terms of networks and selection of cellular function in terms of trees. Otherwise one gets lost in the woods of neutral evolution.


This article was reviewed by Dr. Eric Bapteste, Dr. Arcady Mushegian, and Dr. Celine Brochier.

FREE PDF GRATIS: Biology Direct




We must keep in mind the humor of calling the central metaphor for evolution "the tree of life". The phrase first appears in Genesis 2:9:

And the LORD God made all kinds of trees grow out of the ground--trees that were pleasing to the eye and good for food. In the middle of the garden were the tree of life and the tree of the knowledge of good and evil.

There is irony in using the name of a tree central to the creation story to argue against that very myth. Therefore we doubt that any phrase will ever pack as much punch as the "tree of life", even if the pattern of common descent is more of a web. It is very important that the community stops labeling any tree derived from a single data source the TOL. The recent attempts to resolve the TOC using primary sequence should be labeled "universal sequence trees", a name that is grounded in the limitations of the data. The title TOC should be reserved for branch orders that are supported by several lines of independent evidence, and the TOL should be the synthesis of those branch orders and horizontal process.

Biólogos desbloqueiam código regulador da maioria dos genes humanos: mero acaso, fortuita necessidade ou design inteligente?

The human initiator is a distinct and abundant element that is precisely positioned in focused core promoters

Long Vo ngoc, California Jack Cassidy, Cassidy Yunjing Huang, Sascha H.C. Duttke and James T. Kadonaga

- Author Affiliations

Section of Molecular Biology, University of California at San Diego, La Jolla, California 92093, USA

Corresponding author: jkadonaga@ucsd.edu


DNA sequence signals in the core promoter, such as the initiator (Inr), direct transcription initiation by RNA polymerase II. Here we show that the human Inr has the consensus of BBCA+1BW at focused promoters in which transcription initiates at a single site or a narrow cluster of sites. The analysis of 7678 focused transcription start sites revealed 40% with a perfect match to the Inr and 16% with a single mismatch outside of the CA+1 core. TATA-like sequences are underrepresented in Inr promoters. This consensus is a key component of the DNA sequence rules that specify transcription initiation in humans.

Keywords: RNA polymerase II initiator core promoter transcription start site focused transcription


Supplemental material is available for this article.

Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.293837.116.

Received November 14, 2016. Accepted December 19, 2016.

© 2017 Vo ngoc et al.; Published by Cold Spring Harbor Laboratory Press

This article is distributed exclusively by Cold Spring Harbor Laboratory Press for the first six months after the full-issue publication date (see http://genesdev.cshlp.org/site/misc/terms.xhtml). After six months, it is available under a Creative Commons License (Attribution-NonCommercial 4.0 International), as described at http://creativecommons.org/licenses/by-nc/4.0/.


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