cr In Belize, Critically endangered wrasse now favorite food of invasive lionfish By insider.si.edu Published On :: Mon, 04 May 2015 14:58:38 +0000 Scientists examining the stomach contents of invasive lionfish caught on the inner barrier reef of Belize have discovered that nearly half of the diet of […] The post In Belize, Critically endangered wrasse now favorite food of invasive lionfish appeared first on Smithsonian Insider. Full Article Marine Science Research News Science & Nature conservation biology coral reefs endangered species fishes invasive species National Museum of Natural History
cr Hi-Tech Analysis Cracks Curious Case of Contaminated Cremains By insider.si.edu Published On :: Thu, 07 May 2015 16:49:10 +0000 Studies show that on average, the weight of cremated remains for men is about 7.13 pounds (plus or minus 1.2 pounds) and for women, 4.9 […] The post Hi-Tech Analysis Cracks Curious Case of Contaminated Cremains appeared first on Smithsonian Insider. Full Article Anthropology Research News Science & Nature geology materials science National Museum of Natural History osteology
cr The oldest microscope in the museum By insider.si.edu Published On :: Thu, 14 May 2015 13:02:54 +0000 In the store-rooms of the National Museum of American History curators recently discovered a small microscope made around 1750 by John Cuff (1708-1772), a […] The post The oldest microscope in the museum appeared first on Smithsonian Insider. Full Article Science & Nature Spotlight materials science National Museum of American History
cr Sol Man: John Grant is on a road trip across Mars By insider.si.edu Published On :: Mon, 06 Jul 2015 13:25:41 +0000 Two rovers are active right now on the surface of Mars: Opportunity, which landed in January 2004, and Curiosity, which started exploration in August 2012. […] The post Sol Man: John Grant is on a road trip across Mars appeared first on Smithsonian Insider. Full Article Meet Our People Q & A Research News Science & Nature Space astronomy astrophysics National Air and Space Museum prehistoric rocks & minerals technology
cr Interstellar Seeds Could Create Oases of Life By insider.si.edu Published On :: Thu, 27 Aug 2015 16:12:53 +0000 We only have one example of a planet with life: Earth. But within the next generation, it should become possible to detect signs of life […] The post Interstellar Seeds Could Create Oases of Life appeared first on Smithsonian Insider. Full Article Research News Science & Nature Space astronomy astrophysics Center for Astrophysics | Harvard & Smithsonian Smithsonian Astrophysical Observatory
cr Waiter, There’s a Tag on My Crab! By insider.si.edu Published On :: Tue, 29 Sep 2015 15:16:13 +0000 When the population of one of the Chesapeake Bay’s most famous residents, the blue crab, went into rapid decline due to overfishing, the Smithsonian stepped […] The post Waiter, There’s a Tag on My Crab! appeared first on Smithsonian Insider. Full Article Marine Science Snapshot
cr VERITAS Detects Gamma Rays from Galaxy Halfway Across the Visible Universe By insider.si.edu Published On :: Tue, 15 Dec 2015 15:11:34 +0000 In April 2015, after traveling for about half the age of the universe, a flood of powerful gamma rays from a distant galaxy slammed into […] The post VERITAS Detects Gamma Rays from Galaxy Halfway Across the Visible Universe appeared first on Smithsonian Insider. Full Article Research News Science & Nature Space astronomy astrophysics Center for Astrophysics | Harvard & Smithsonian Smithsonian Astrophysical Observatory
cr Smithsonian scientist creating DNA database to track Caribbean conch and lobster By insider.si.edu Published On :: Thu, 24 Mar 2016 21:24:15 +0000 Smothered in tartar sauce and cheese it’s difficult to know just what species of fish lurks beneath the breaded surface of a fast-food fish sandwich. […] The post Smithsonian scientist creating DNA database to track Caribbean conch and lobster appeared first on Smithsonian Insider. Full Article Animals Marine Science Q & A Research News Science & Nature biodiversity conservation biology endangered species fishes National Museum of Natural History
cr Sacred shrew mummies reveal species distribution in ancient Egypt By insider.si.edu Published On :: Fri, 22 Apr 2016 14:32:15 +0000 Nocturnal, solitary and fiercely territorial the adult Egyptian pigmy shrew—one of the smallest mammals on earth—weighs just 7 grams. French zoologist Isidore Geoffroy Saint-Hilaire first […] The post Sacred shrew mummies reveal species distribution in ancient Egypt appeared first on Smithsonian Insider. Full Article Animals Anthropology Science & Nature archaeology biodiversity mammals National Museum of Natural History
cr Smithsonian Expert Urges Caution, Patience on Blue Crab Recovery By insider.si.edu Published On :: Mon, 25 Apr 2016 12:39:47 +0000 The results are in, 2016 is going to be a good year for blue crabs in the Chesapeake Bay. An iconic figure embedded in the […] The post Smithsonian Expert Urges Caution, Patience on Blue Crab Recovery appeared first on Smithsonian Insider. Full Article Animals Marine Science Research News Science & Nature Chesapeake Bay conservation biology fishes Smithsonian Environmental Research Center
cr First hooded crane hatches @ SCBI By insider.si.edu Published On :: Fri, 29 Jul 2016 11:02:40 +0000 The Smithsonian Conservation Biology Institute (SCBI) hatched its first hooded crane chick June 14. The chick was born as the result of artificial insemination. The […] The post First hooded crane hatches @ SCBI appeared first on Smithsonian Insider. Full Article Animals Science & Nature Spotlight birds conservation biology endangered species Smithsonian Conservation Biology Institute Smithsonian's National Zoo
cr Crime bite: DNA on half-eaten food may someday send crooks to jail By insider.si.edu Published On :: Mon, 08 Aug 2016 15:12:34 +0000 A bite mark on a homicide victim’s skin is not an unusual discovery. A criminal’s teeth marks are also occasionally found on food at a […] The post Crime bite: DNA on half-eaten food may someday send crooks to jail appeared first on Smithsonian Insider. Full Article Anthropology Science & Nature National Museum of Natural History
cr Tiny ocean crustaceans wear invisibility cloak of living bacteria By insider.si.edu Published On :: Fri, 28 Oct 2016 07:45:54 +0000 Crustaceans that thrive in the vastness of the open ocean have no place to hide from their predators. Consequently, many creatures that live at depths […] The post Tiny ocean crustaceans wear invisibility cloak of living bacteria appeared first on Smithsonian Insider. Full Article Animals History & Culture Marine Science Research News Science & Nature Spotlight National Museum of Natural History
cr New parasitic crab species discovered during Smithsonian Biocube work in Solomon Islands By insider.si.edu Published On :: Fri, 09 Dec 2016 15:23:31 +0000 A one-cubic-foot approach to studying biodiversity as showcased in the new Biocube exhibit at the Smithsonian’s National Museum of Natural History has led to the […] The post New parasitic crab species discovered during Smithsonian Biocube work in Solomon Islands appeared first on Smithsonian Insider. Full Article Animals Marine Science Research News Science & Nature biodiversity conservation biology fishes National Museum of Natural History new species
cr Meet the candy striped hermit crab, a new Caribbean species By insider.si.edu Published On :: Thu, 26 Jan 2017 14:43:20 +0000 Recent underwater photographs and video from the National Marine Park of the southern Caribbean island of Bonaire has led to the discovery of a new species […] The post Meet the candy striped hermit crab, a new Caribbean species appeared first on Smithsonian Insider. Full Article Animals Marine Science Research News Science & Nature biodiversity Caribbean fishes National Museum of Natural History
cr Study determines microscopic water bears will be Earth’s last survivors By insider.si.edu Published On :: Wed, 19 Jul 2017 16:53:32 +0000 The world’s most indestructible species, the tardigrade, an eight-legged micro-animal, also known as the water bear, will survive until the Sun dies, according to a […] The post Study determines microscopic water bears will be Earth’s last survivors appeared first on Smithsonian Insider. Full Article Animals Marine Science Research News Science & Nature Space Spotlight asteroids astronomy astrophysics Center for Astrophysics | Harvard & Smithsonian extinction Smithsonian Astrophysical Observatory
cr Laser beams unveil secrets locked inside primitive stone spear points By insider.si.edu Published On :: Fri, 28 Jul 2017 15:22:42 +0000 In a new study in which one of humankind’s most high-tech tools was used to analyze one of its most primitive, scientists have uncovered evidence […] The post Laser beams unveil secrets locked inside primitive stone spear points appeared first on Smithsonian Insider. Full Article Anthropology Science & Nature National Museum of Natural History
cr What does candied, microwaved sperm have to do with saving endangered species? By insider.si.edu Published On :: Mon, 06 Nov 2017 19:22:17 +0000 Today’s cutting-edge laboratories rely on ultra-cold refrigeration to keep delicate cells like sperm viable for use in the future. But a new technique using microwaves […] The post What does candied, microwaved sperm have to do with saving endangered species? appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature Smithsonian Conservation Biology Institute Smithsonian's National Zoo
cr With voices joined in chorus, giant otter families create a distinct sound signature By insider.si.edu Published On :: Wed, 15 Nov 2017 20:05:52 +0000 With a non-stop babble of hums, grunts and shrill squeals as they argue over fish and defend their territories, the Amazon’s giant otters are one […] The post With voices joined in chorus, giant otter families create a distinct sound signature appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature conservation endangered species mammals Smithsonian Tropical Research Institute South America
cr Some dolphins cross the Pacific more easily than others. Why that matters for protecting them By insider.si.edu Published On :: Fri, 04 May 2018 11:31:12 +0000 Marine mammologist Matthew Leslie aims his crossbow from the bow of a moving boat at the dolphins riding the breaking waves below. A dolphin will […] The post Some dolphins cross the Pacific more easily than others. Why that matters for protecting them appeared first on Smithsonian Insider. Full Article Animals Marine Science Science & Nature National Museum of Natural History
cr Space is the best place to eat ice cream By insider.si.edu Published On :: Tue, 03 Jul 2018 12:08:51 +0000 Imagine a place where ice cream never drips. Ice cream lovers, how far would you be willing to go to avoid that heartbreaking moment where […] The post Space is the best place to eat ice cream appeared first on Smithsonian Insider. Full Article History & Culture Science & Nature Space National Air and Space Museum
cr The crane that fell for her keeper By insider.si.edu Published On :: Tue, 07 Aug 2018 19:36:20 +0000 The post The crane that fell for her keeper appeared first on Smithsonian Insider. Full Article Animals History & Culture Science & Nature Spotlight captive breeding Smithsonian Conservation Biology Institute
cr Screwed up DNS entry By www.bleepingcomputer.com Published On :: 2020-05-07T04:01:31-05:00 Full Article
cr The crystal structure of the TonB-dependent transporter YncD reveals a positively charged substrate-binding site By scripts.iucr.org Published On :: 2020-04-27 The outer membrane of Gram-negative bacteria is highly impermeable to hydrophilic molecules of larger than 600 Da, protecting these bacteria from toxins present in the environment. In order to transport nutrients across this impermeable membrane, Gram-negative bacteria utilize a diverse family of outer-membrane proteins called TonB-dependent transporters. The majority of the members of this family transport iron-containing substrates. However, it is becoming increasingly clear that TonB-dependent transporters target chemically diverse substrates. In this work, the structure and phylogenetic distribution of the TonB-dependent transporter YncD are investigated. It is shown that while YncD is present in some enteropathogens, including Escherichia coli and Salmonella spp., it is also widespread in Gammaproteobacteria and Betaproteobacteria of environmental origin. The structure of YncD was determined, showing that despite a distant evolutionary relationship, it shares structural features with the ferric citrate transporter FecA, including a compact positively charged substrate-binding site. Despite these shared features, it is shown that YncD does not contribute to the growth of E. coli in pure culture under iron-limiting conditions or with ferric citrate as an iron source. Previous studies of transcriptional regulation in E. coli show that YncD is not induced under iron-limiting conditions and is unresponsive to the ferric uptake regulator (Fur). These observations, combined with the data presented here, suggest that YncD is not responsible for the transport of an iron-containing substrate. Full Article text
cr Bond-valence analyses of the crystal structures of FeMo/V cofactors in FeMo/V proteins By scripts.iucr.org Published On :: 2020-04-15 The bond-valence method has been used for valence calculations of FeMo/V cofactors in FeMo/V proteins using 51 crystallographic data sets of FeMo/V proteins from the Protein Data Bank. The calculations show molybdenum(III) to be present in MoFe7S9C(Cys)(HHis)[R-(H)homocit] (where H4homocit is homocitric acid, HCys is cysteine and HHis is histidine) in FeMo cofactors, while vanadium(III) with a more reduced iron complement is obtained for FeV cofactors. Using an error analysis of the calculated valences, it was found that in FeMo cofactors Fe1, Fe6 and Fe7 can be unambiguously assigned as iron(III), while Fe2, Fe3, Fe4 and Fe5 show different degrees of mixed valences for the individual Fe atoms. For the FeV cofactors in PDB entry 5n6y, Fe4, Fe5 and Fe6 correspond to iron(II), iron(II) and iron(III), respectively, while Fe1, Fe2, Fe3 and Fe7 exhibit strongly mixed valences. Special situations such as CO-bound and selenium-substituted FeMo cofactors and O(N)H-bridged FeV cofactors are also discussed and suggest rearrangement of the electron configuration on the substitution of the bridging S atoms. Full Article text
cr Crystal and solution structures of fragments of the human leucocyte common antigen-related protein By scripts.iucr.org Published On :: 2020-04-15 Leucocyte common antigen-related protein (LAR) is a post-synaptic type I transmembrane receptor protein that is important for neuronal functionality and is genetically coupled to neuronal disorders such as attention deficit hyperactivity disorder (ADHD). To understand the molecular function of LAR, structural and biochemical studies of protein fragments derived from the ectodomain of human LAR have been performed. The crystal structure of a fragment encompassing the first four FNIII domains (LARFN1–4) showed a characteristic L shape. SAXS data suggested limited flexibility within LARFN1–4, while rigid-body refinement of the SAXS data using the X-ray-derived atomic model showed a smaller angle between the domains defining the L shape compared with the crystal structure. The capabilities of the individual LAR fragments to interact with heparin was examined using microscale thermophoresis and heparin-affinity chromatography. The results showed that the three N-terminal immunoglobulin domains (LARIg1–3) and the four C-terminal FNIII domains (LARFN5–8) both bound heparin, while LARFN1–4 did not. The low-molecular-weight heparin drug Innohep induced a shift in hydrodynamic volume as assessed by size-exclusion chromatography of LARIg1–3 and LARFN5–8, while the chemically defined pentameric heparin drug Arixtra did not. Together, the presented results suggest the presence of an additional heparin-binding site in human LAR. Full Article text
cr Macromolecular X-ray crystallography: soon to be a road less travelled? By scripts.iucr.org Published On :: 2020-04-30 The number of new X-ray crystallography-based submissions to the Protein Data Bank appears to be at the beginning of a decline, perhaps signalling an end to the era of the dominance of X-ray crystallography within structural biology. This letter, from the viewpoint of a young structural biologist, applies the Copernican method to the life expectancy of crystallography and asks whether the technique is still the mainstay of structural biology. A study of the rate of Protein Data Bank depositions allows a more nuanced analysis of the fortunes of macromolecular X-ray crystallography and shows that cryo-electron microscopy might now be outcompeting crystallography for new labour and talent, perhaps heralding a change in the landscape of the field. Full Article text
cr New Book: “Only the Wing: Reimar Horten’s Epic Quest to Stabilize and Control the All-Wing Aircraft” By insider.si.edu Published On :: Thu, 28 Apr 2011 19:09:53 +0000 Only the Wing is a new book by Russell Lee that recounts Horten's epic quest to stabalize and control the all-wing aircraft. The post New Book: “Only the Wing: Reimar Horten’s Epic Quest to Stabilize and Control the All-Wing Aircraft” appeared first on Smithsonian Insider. Full Article Book Review aeronautics National Air and Space Museum
cr New Book: “Sweet Stuff: An American History of Sweeteners from Sugar to Sucralose” By insider.si.edu Published On :: Mon, 17 Oct 2011 14:35:38 +0000 Warner’s narrative covers the major natural sweeteners, including sugar, molasses from cane, beet sugar, corn syrup, honey and maple, as well as artificial sweeteners such as saccharin, cyclamate, aspartame and sucralose. The post New Book: “Sweet Stuff: An American History of Sweeteners from Sugar to Sucralose” appeared first on Smithsonian Insider. Full Article Book Review National Museum of American History
cr New Book: “Across Atlantic Ice : The Origin of America’s Clovis Culture” By insider.si.edu Published On :: Tue, 31 Jan 2012 20:06:35 +0000 Supplying archaeological and oceanographic evidence, this book persuasively links Clovis technology with the culture of the Solutrean people who occupied France and Spain more than 20,000 years ago. The post New Book: “Across Atlantic Ice : The Origin of America’s Clovis Culture” appeared first on Smithsonian Insider. Full Article Anthropology Book Review Science & Nature National Museum of Natural History
cr New Book: “Recreating First Contact: Expeditions, Anthropology, and Popular Culture” By insider.si.edu Published On :: Wed, 30 Oct 2013 14:36:51 +0000 Between the world wars of the early Twentieth Century, an age of adventure travel and cultural exploration flourished when newly developed transport and recording technologies–particularly […] The post New Book: “Recreating First Contact: Expeditions, Anthropology, and Popular Culture” appeared first on Smithsonian Insider. Full Article Anthropology Book Review Research News Science & Nature National Museum of Natural History
cr Secret Adventures: “Claws and Effect” By insider.si.edu Published On :: Thu, 03 Nov 2016 17:57:53 +0000 This Secret Smithsonian Adventures series follows four middle schoolers as they foil events by two dastardly doers who try to dangerously change the true course […] The post Secret Adventures: “Claws and Effect” appeared first on Smithsonian Insider. Full Article Animals Book Review Dinosaurs & Fossils History & Culture Science & Nature Spotlight dinosaurs National Museum of Natural History
cr The dimeric organization that enhances the microtubule end-binding affinity of EB1 is susceptible to phosphorylation [RESEARCH ARTICLE] By jcs.biologists.org Published On :: 2020-03-09T08:45:03-07:00 Yinlong Song, Yikan Zhang, Ying Pan, Jianfeng He, Yan Wang, Wei Chen, Jing Guo, Haiteng Deng, Yi Xue, Xianyang Fang, and Xin LiangMicrotubules dynamics is regulated by the plus end-tracking proteins (+TIPs) in cells. End binding protein 1 (EB1) acts as a master regulator in +TIPs networks by targeting microtubule growing ends and recruiting other factors. However, the molecular mechanism of how EB1 binds to microtubule ends with a high affinity remains to be an open question. Using single-molecule imaging, we show that the end-binding kinetics of EB1 changes along with the polymerizing and hydrolysis rate of tubulin dimers, confirming the binding of EB1 to GTP/GDP-Pi tubulin at microtubule growing ends. The affinity of wild-type EB1 to these sites is higher than monomeric EB1 mutants, suggesting that two CH domains in the dimer contribute to the end-binding. Introducing phosphomimicking mutations into the linker domain of EB1 weakens the end-binding affinity and confers a more curved conformation to EB1 dimer without compromising dimerization, suggesting that the overall architecture of EB1 is important for the end-binding affinity. Taken together, our results provide insights into understanding how the high-affinity end-binding of EB1 can be achieved and how this activity may be regulated in cells. Full Article
cr EML4-ALK V3 oncogenic fusion proteins promote microtubule stabilization and accelerated migration through NEK9 and NEK7 [RESEARCH ARTICLE] By jcs.biologists.org Published On :: 2020-03-17T03:51:28-07:00 Laura O'Regan, Giancarlo Barone, Rozita Adib, Chang Gok Woo, Hui Jeong Jeong, Emily L. Richardson, Mark W. Richards, Patricia A.J. Muller, Spencer J. Collis, Dean A. Fennell, Jene Choi, Richard Bayliss, and Andrew M. FryEML4-ALK is an oncogenic fusion present in ~5% non-small cell lung cancers. However, alternative breakpoints in the EML4 gene lead to distinct variants with different patient outcomes. Here, we show in cell models that EML4-ALK variant 3 (V3), which is linked to accelerated metastatic spread, causes microtubule stabilization, formation of extended cytoplasmic protrusions and increased cell migration. It also recruits the NEK9 and NEK7 kinase to microtubules via the N-terminal EML4 microtubule-binding region. Overexpression of wild-type EML4 as well as constitutive activation of NEK9 also perturb cell morphology and accelerate migration in a microtubule-dependent manner that requires the downstream kinase NEK7 but not ALK activity. Strikingly, elevated NEK9 expression is associated with reduced progression-free survival in EML4-ALK patients. Hence, we propose that EML4-ALK V3 promotes microtubule stabilization through NEK9 and NEK7 leading to increased cell migration. This represents a novel actionable pathway that could drive metastatic disease progression in EML4-ALK lung cancer. Full Article
cr Actin waves transport RanGTP to the neurite tip to regulate non-centrosomal microtubules in neurons [RESEARCH ARTICLE] By jcs.biologists.org Published On :: 2020-04-06T07:46:57-07:00 Yung-An Huang, Chih-Hsuan Hsu, Ho-Chieh Chiu, Pei-Yu Hsi, Chris T. Ho, Wei-Lun Lo, and Eric HwangMicrotubule (MT) is the most abundant cytoskeleton in neurons and controls multiple facets of their development. While the MT-organizing center (MTOC) in mitotic cells is typically located at the centrosome, MTOC in neurons switches to non-centrosomal sites. A handful of cellular components have been shown to promote non-centrosomal MT (ncMT) formation in neurons, yet the regulation mechanism remains unknown. Here we demonstrate that the small GTPase Ran is a key regulator of ncMTs in neurons. Using an optogenetic tool that enables light-induced local production of RanGTP, we demonstrate that RanGTP promotes ncMT plus-end growth along the neurite. Additionally, we discovered that actin waves drive the anterograde transport of RanGTP. Pharmacological disruption of actin waves abolishes the enrichment of RanGTP and reduces growing ncMT plus-ends at the neurite tip. These observations identify a novel regulation mechanism of ncMTs and pinpoint an indirect connection between the actin and MT cytoskeletons in neurons. Full Article
cr Primary myeloid cell proteomics and transcriptomics: importance of ss tubulin isotypes for osteoclast function [RESEARCH ARTICLE] By jcs.biologists.org Published On :: 2020-04-07T06:16:39-07:00 David Guerit, Pauline Marie, Anne Morel, Justine Maurin, Christel Verollet, Brigitte Raynaud-Messina, Serge Urbach, and Anne BlangyAmong hematopoietic cells, osteoclasts (Oc) and immature dendritic cells (Dc) are closely related myeloid cells with distinct functions; Oc participate skeleton maintenance while Dc sample the environment for foreign antigens. Such specificities rely on profound modifications of gene and protein expression during Oc and Dc differentiation. We provide global proteomic and transcriptomic analyses of primary mouse Oc and Dc, based on original SILAC and RNAseq data. We established specific signatures for Oc and Dc including genes and proteins of unknown functions. In particular, we showed that Oc and Dc have the same α and β tubulin isotypes repertoire but that Oc express much more β tubulin isotype Tubb6. In both mouse and human Oc, we demonstrate that elevated expression of Tubb6 in Oc is necessary for correct podosomes organization and thus for the structure of the sealing zone, which sustains the bone resorption apparatus. Hence, lowering Tubb6 expression hindered Oc resorption activity. Overall, we highlight here potential new regulators of Oc and Dc biology and illustrate the functional importance of the tubulin isotype repertoire in the biology of differentiated cells. Full Article
cr Micro-stepping Extended Focus reduces photobleaching and preserves structured illumination super-resolution features [TOOLS AND RESOURCES] By jcs.biologists.org Published On :: 2020-04-07T06:16:39-07:00 Xian Hu, Salma Jalal, Michael Sheetz, Oddmund Bakke, and Felix MargadantDespite progress made in confocal microscopy, even fast systems still have insufficient temporal resolution for detailed live cell volume imaging, such as tracking rapid movement of membrane vesicles in three-dimensional space. Depending on the shortfall, this may result in undersampling and/or motion artifacts that ultimately limit the quality of the imaging data. By sacrificing detailed information in the Z-direction, we propose a new imaging modality that involves capturing fast "projections" from the field of depth which shortens imaging time by approximately an order of magnitude as compared to standard volumetric confocal imaging. With faster imaging, radiation exposure to the sample is reduced, resulting in less fluorophore photobleaching and potential photodamage. The implementation minimally requires two synchronized control signals that drive a piezo stage and trigger the camera exposure. The device generating the signals has been tested on spinning disk confocals and instant structured-illumination-microscopy (iSIM) microscopes. Our calibration images show that the approach provides highly repeatable and stable imaging conditions that enable photometric measurements of the acquired data, in both standard live imaging and super-resolution modes. Full Article
cr Automated 3D light-sheet screening with high spatiotemporal resolution reveals mitotic phenotypes [TOOLS AND RESOURCES] By jcs.biologists.org Published On :: 2020-04-15T01:46:56-07:00 Björn Eismann, Teresa G. Krieger, Jürgen Beneke, Ruben Bulkescher, Lukas Adam, Holger Erfle, Carl Herrmann, Roland Eils, and Christian Conrad3D cell cultures enable the in vitro study of dynamic biological processes such as the cell cycle, but their use in high-throughput screens remains impractical with conventional fluorescent microscopy. Here, we present a screening workflow for the automated evaluation of mitotic phenotypes in 3D cell cultures by light-sheet microscopy. After sample preparation by a liquid handling robot, cell spheroids are imaged for 24 hours in toto with a dual-view inverted selective plane illumination microscope (diSPIM) with a much improved signal-to-noise ratio, higher imaging speed, isotropic resolution and reduced light exposure compared to a spinning disc confocal microscope. A dedicated high-content image processing pipeline implements convolutional neural network based phenotype classification. We illustrate the potential of our approach by siRNA knock-down and epigenetic modification of 28 mitotic target genes for assessing their phenotypic role in mitosis. By rendering light-sheet microscopy operational for high-throughput screening applications, this workflow enables target gene characterization or drug candidate evaluation in tissue-like 3D cell culture models. Full Article
cr Kinesin-14s and microtubule dynamics define fission yeast mitotic and meiotic spindle assembly and elongation [RESEARCH ARTICLE] By jcs.biologists.org Published On :: 2020-04-23T01:49:49-07:00 Ana Loncar, Sergio A. Rincon, Manuel Lera Ramirez, Anne Paoletti, and Phong T. TranTo segregate the chromosomes faithfully during cell division, cells assemble a spindle that captures the kinetochores and pulls them towards opposite poles. Proper spindle function requires correct interplay between microtubule motors and non-motor proteins. Defects in spindle assembly or changes in spindle dynamics are associated with diseases like cancer or developmental disorders. Here we compared mitotic and meiotic spindles in fission yeast. We show that even though mitotic and meiotic spindles undergo the typical three phases of spindle elongation, they have distinct features. We found that the relative concentration of kinesin-14 Pkl1 is decreased in meiosis I compared to mitosis, while the concentration of kinesin-5 Cut7 remains constant. We identified the second kinesin-14 Klp2 and microtubule dynamics as factors necessary for proper meiotic spindle assembly. This work defines differences between mitotic and meiotic spindles in fission yeast, and provides prospect for future comparative studies. Full Article
cr En bloc TGN recruitment of Aspergillus TRAPPII reveals TRAPP maturation as unlikely to drive RAB1-to-RAB11 transition [RESEARCH ARTICLE] By jcs.biologists.org Published On :: 2020-04-23T01:49:49-07:00 M. Pinar and M. A. PenalvaTRAnsport Protein Particle (TRAPP) complexes regulate membrane traffic. TRAPPII and TRAPPIII share a core hetero-heptamer, also denoted TRAPPI. In fungi TRAPPIII and TRAPPII mediate GDP exchange on RAB1 and RAB11, respectively, regulating traffic across the Golgi, with TRAPPIII also activating RAB1 in autophagosomes. Our finding that Aspergillus nidulans TRAPPII can be assembled by addition of a TRAPPII-specific subcomplex onto core TRAPP prompted us to investigate the possibility that TRAPPI/TRAPPIII already residing in the Golgi matures into TRAPPII to determine a RAB1-to-RAB11 conversion as Golgi cisternae progress from early Golgi to TGN identity. By time-resolved microscopy we determine that the TRAPPII reporter Trs120/TRAPPC9 is recruited to existing TGN cisternae slightly before RAB11 arrives, and resides for~45 sec on them before cisternae tear off into RAB11 secretory carriers. Notably, the core TRAPP reporter Bet3/TRAPPC3 was not detectable in early Golgi cisternae, being instead recruited to TGN cisternae simultaneously with Trs120/TRAPPC9, indicating en bloc recruitment of TRAPPII to the Golgi and arguing strongly against the TRAPP maturation model. Full Article
cr Cdc24 interacts with the septins to create a positive feedback during bud site assembly in yeast [RESEARCH ARTICLE] By jcs.biologists.org Published On :: 2020-04-29T02:35:34-07:00 Julian Chollet, Alexander Dünkler, Anne Bäuerle, Laura Vivero-Pol, Medhanie A. Mulaw, Thomas Gronemeyer, and Nils JohnssonYeast cells select the position of their new bud at the beginning of each cell cycle. The recruitment of the septins to this prospective bud site is one of the critical events in a complex assembly pathway that culminates in the outgrowth of a new daughter cell. Hereby, the septin-rods follow the high concentration of Cdc42GTP that is generated by the focused localization of its GEF Cdc24. We show that shortly before budding Cdc24 not only activates Cdc42 but also transiently interacts with Cdc11, the septin subunit that caps both ends of the septin rods. Mutations in Cdc24 reducing the affinity to Cdc11 impair septin recruitment and decrease the stability of the polarity patch. The interaction between septins and Cdc24 thus reinforces bud assembly at sites where septin structures are formed. Once the septins polymerize into the ring, Cdc24 is found at the cortex of the bud and directs its further outgrowth from this position. Full Article
cr OPTN recruitment to a Golgi-proximal compartment regulates immune signalling and cytokine secretion [RESEARCH ARTICLE] By jcs.biologists.org Published On :: 2020-05-06T08:30:40-07:00 Thomas O'Loughlin, Antonina J. Kruppa, Andre L. R. Ribeiro, James R. Edgar, Abdulaziz Ghannam, Andrew M. Smith, and Folma BussOptineurin (OPTN) is a multifunctional protein involved in autophagy, secretion as well as NF-B and IRF3 signalling and OPTN mutations are associated with several human diseases. Here we show that, in response to viral RNA, OPTN translocates to foci in the perinuclear region, where it negatively regulates NF-B and IRF3 signalling pathways and downstream pro-inflammatory cytokine secretion. These OPTN foci consist of a tight cluster of small membrane vesicles, which are positive for ATG9A. Disease mutations linked to POAG cause aberrant foci formation in the absence of stimuli, which correlates with the ability of OPTN to inhibit signalling. Using proximity labelling proteomics, we identify the LUBAC complex, CYLD and TBK1 as part of the OPTN interactome and show that these proteins are recruited to this OPTN-positive perinuclear compartment. Our work uncovers a crucial role for OPTN in dampening NF-B and IRF3 signalling through the sequestration of LUBAC and other positive regulators in this viral RNA-induced compartment leading to altered pro-inflammatory cytokine secretion. Full Article
cr LIN28A binds to meiotic gene transcripts and modulates translation in male germ cells [RESEARCH ARTICLE] By jcs.biologists.org Published On :: 2020-05-06T08:30:40-07:00 Mei Wang, Luping Yu, Shu Wang, Fan Yang, Min Wang, Lufan Li, and Xin WuRNA-binding protein LIN28A is required for maintaining tissue homeostasis, including the reproductive system, but the underlying mechanisms on how LIN28A regulates germline progenitors remain unclear. Here, we dissected LIN28A-binding targets using high-throughput sequencing of RNAs isolated by crosslinking immunoprecipitation (HITS-CLIP) in the mouse testes. LIN28A preferentially binds to CDS or 3'UTR regions through these sites with GGAG(A) sequences enriched within mRNAs. Further investigation of Lin28a null mouse testes indicated that meiosis-associated mRNAs mediated by LIN28A were differentially expressed. Next, ribosome profiling revealed that the mRNA levels of these targets were significantly reduced in polysome fractions, and their protein expression levels decreased in the Lin28a null mouse testes, even when meiotic arrest in null mouse testes was not apparent. Collectively, these findings provide a set of binding targets that are regulated by LIN28A, which may potentially be the mechanism for the prominent role of LIN28A in regulating mammalian undifferentiated spermatogonia fates and male fertility. Full Article
cr Glucocorticoids rapidly inhibit cell migration through a novel, non-transcriptional HDAC6 pathway [RESEARCH ARTICLE] By jcs.biologists.org Published On :: 2020-05-07T00:45:50-07:00 Stephen Kershaw, David J. Morgan, James Boyd, David G. Spiller, Gareth Kitchen, Egor Zindy, Mudassar Iqbal, Magnus Rattray, Chris M. Sanderson, Andrew Brass, Claus Jorgensen, Tracy Hussell, Laura C. Matthews, and David W. RayGlucocorticoids (GCs) act through the glucocorticoid receptor (GR) to regulate immunity, energy metabolism, and tissue repair. Upon ligand binding, activated GR mediates cellular effects by regulating gene expression, but some GR effects can occur rapidly without new transcription. We show GCs rapidly inhibit cell migration, in response to both GR agonist and antagonist ligand binding. The inhibitory effect on migration is prevented by GR knockdown with siRNA, confirming GR specificity, but not by actinomycin D treatment, suggesting a non-transcriptional mechanism. We identified a rapid onset increase in microtubule polymerisation following glucocorticoid treatment, identifying cytoskeletal stabilisation as the likely mechanism of action. HDAC6 overexpression, but not knockdown of αTAT1, rescued the GC effect, implicating HDAC6 as the GR effector. Consistent with this hypothesis, ligand-dependent cytoplasmic interaction between GR and HDAC6 was demonstrated by quantitative imaging. Taken together, we propose that activated GR inhibits HDAC6 function and thereby increases the stability of the microtubule network to reduce cell motility. We therefore report a novel, non-transcriptional mechanism whereby GCs impair cell motility through inhibition of HDAC6 and rapid reorganization of the cell architecture. Full Article
cr Gale Crater to be landing site for NASA’s Mars Science Laboratory By insider.si.edu Published On :: Fri, 22 Jul 2011 16:29:12 +0000 During a press conference Friday, July 22 at the Smithsonian's National Air and Space Museum, NASA announced that Gale Crater will be the landing site for the Mars Science Laboratory. Scheduled to launch in late 2011 and arrive at Mars in August 2012, the Mars Science Laboratory is a rover that will assess the planet’s “habitability”—if it ever was, or is today, an environment able to support microbial life. The post Gale Crater to be landing site for NASA’s Mars Science Laboratory appeared first on Smithsonian Insider. Full Article Earth Science Research News Science & Nature Space astronomy astrophysics National Air and Space Museum rocks & minerals
cr Photos reveal recent activity in moon’s crust By insider.si.edu Published On :: Tue, 28 Feb 2012 13:03:20 +0000 New images from NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft show the moon's crust is being stretched, forming minute valleys in a few small areas on the lunar surface. The post Photos reveal recent activity in moon’s crust appeared first on Smithsonian Insider. Full Article Earth Science Science & Nature Space astronomy astrophysics geology National Air and Space Museum rocks & minerals
cr Iowa meteorite crater confirmed By insider.si.edu Published On :: Tue, 05 Mar 2013 20:21:08 +0000 Recent airborne geophysical surveys near Decorah, Iowa are providing an unprecedented look at a 470-million-year-old meteorite crater concealed beneath bedrock and sediments. The aerial surveys, […] The post Iowa meteorite crater confirmed appeared first on Smithsonian Insider. Full Article Earth Science Science & Nature Space astronomy astrophysics geology meteorites National Museum of Natural History prehistoric rocks & minerals
cr Rolled-Up Mystery Mineral may cause Craving for Piroulines By insider.si.edu Published On :: Fri, 17 Apr 2015 13:09:32 +0000 Forget what you thought you knew about geology. Some minerals can roll up like flaky Belgian piroulines. For the last several decades, mining operations in […] The post Rolled-Up Mystery Mineral may cause Craving for Piroulines appeared first on Smithsonian Insider. Full Article Earth Science Research News Science & Nature geology National Museum of Natural History rocks & minerals
cr Sun-like Star Shows Magnetic Field Critical for Life on the early Earth By insider.si.edu Published On :: Fri, 18 Mar 2016 12:06:53 +0000 Nearly four billion years ago, life arose on Earth. Life appeared because our planet had a rocky surface, liquid water, and a blanketing atmosphere. But […] The post Sun-like Star Shows Magnetic Field Critical for Life on the early Earth appeared first on Smithsonian Insider. Full Article Earth Science Research News Space Spotlight Center for Astrophysics | Harvard & Smithsonian Smithsonian Astrophysical Observatory Sun