pi Weight of genitals reduces physical endurance in male orb web spiders, researchers find By insider.si.edu Published On :: Mon, 16 Jul 2012 18:49:44 +0000 The scientists made the spiders exercise by irritating them with a small paint brush and causing them to move around until they became exhausted. Spiders from the group with palps removed were able to travel 300 percent further than spiders with their palps intact. The post Weight of genitals reduces physical endurance in male orb web spiders, researchers find appeared first on Smithsonian Insider. Full Article Animals Science & Nature insects National Museum of Natural History spiders
pi Thieving rodents hiding seeds drives continual rejuvination of tropical forests By insider.si.edu Published On :: Mon, 16 Jul 2012 19:01:22 +0000 By attaching tiny radio transmitters to more than 400 seeds, Patrick Jansen, scientist at the Smithsonian Tropical Research Institute and Wageningen University, and his colleagues found that 85 percent of the seeds were buried in caches by agoutis, common, house cat-sized rodents in tropical lowlands. The post Thieving rodents hiding seeds drives continual rejuvination of tropical forests appeared first on Smithsonian Insider. Full Article Animals Science & Nature conservation biology extinction
pi Tropical arks reach tipping point By insider.si.edu Published On :: Wed, 25 Jul 2012 17:44:45 +0000 Almost half of the tropical forest reserves examined in a new study are ineffective, researchers say. The post Tropical arks reach tipping point appeared first on Smithsonian Insider. Full Article Animals Science & Nature biodiversity carbon dioxide climate change conservation conservation biology endangered species Peru South America Tropical Research Institute
pi Female spiders produce mating plugs to prevent unwanted sex from males By insider.si.edu Published On :: Thu, 02 Aug 2012 09:22:46 +0000 They observed that no plugs were ever formed during mating trials, but instead, females exposed to many males produced the amorphous plugs during the egg-laying process. The post Female spiders produce mating plugs to prevent unwanted sex from males appeared first on Smithsonian Insider. Full Article Animals Science & Nature insects National Museum of Natural History spiders
pi Mississippi State borrows grasshopper collection from Smithsonian By insider.si.edu Published On :: Wed, 22 Aug 2012 17:34:12 +0000 JoVonn Hill, a research associate with the Mississippi Agricultural and Forestry Experiment Station at Mississippi State University, recently borrowed 32,000 grasshoppers from the Smithsonian’s National […] The post Mississippi State borrows grasshopper collection from Smithsonian appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature Spotlight conservation biology
pi Split-personality elliptical galaxy holds a hidden spiral By insider.si.edu Published On :: Thu, 25 Oct 2012 13:51:29 +0000 Astronomers have discovered that one well-known elliptical galaxy has a split personality. Centaurus A is hiding a gassy spiral in its center. The post Split-personality elliptical galaxy holds a hidden spiral appeared first on Smithsonian Insider. Full Article Science & Nature Space astronomy astrophysics Center for Astrophysics | Harvard & Smithsonian galaxies Smithsonian Astrophysical Observatory
pi Female “spidernaut” settles into new home at Smithsonian’s Insect Zoo By insider.si.edu Published On :: Mon, 29 Oct 2012 18:49:13 +0000 The new Sant Director of the National Museum of Natural History, Kirk Johnson, had only been on the job for 26 days when he got […] The post Female “spidernaut” settles into new home at Smithsonian’s Insect Zoo appeared first on Smithsonian Insider. Full Article Animals Science & Nature Space exhibitions National Museum of Natural History spiders
pi Vampire Squid Illustration By insider.si.edu Published On :: Wed, 31 Oct 2012 13:27:42 +0000 Vampire Squid Illustration, 1889 This Smithsonian Snapshot celebrates the Halloween season with this 1889 scientific illustration of a vampire squid from Smithsonian Libraries. Its jet-black […] The post Vampire Squid Illustration appeared first on Smithsonian Insider. Full Article Animals Art Snapshot visual arts
pi Vampire squid By insider.si.edu Published On :: Wed, 31 Oct 2012 18:21:37 +0000 This 1889 scientific illustration of a vampire squid from Smithsonian celebrates Halloween. The squid’s jet-black skin, the caped appearance of the webbing between its arms […] The post Vampire squid appeared first on Smithsonian Insider. Full Article Animals Marine Science Science & Nature Spotlight National Museum of Natural History squid
pi HI-C adds big piece to the solar corona puzzle By insider.si.edu Published On :: Thu, 24 Jan 2013 12:39:01 +0000 But how can the solar atmosphere get hotter, rather than colder, the farther you go from the Sun's surface? A suborbital rocket launched in July provides the answer. The post HI-C adds big piece to the solar corona puzzle appeared first on Smithsonian Insider. Full Article Science & Nature Space astronomy astrophysics Center for Astrophysics | Harvard & Smithsonian Smithsonian Astrophysical Observatory solar eclipse Sun
pi Common tropical bat uses echolocation with precision previously considered impossible, new experiments reveal By insider.si.edu Published On :: Fri, 25 Jan 2013 14:33:07 +0000 Using echolocation alone the bats found, identified and captured insects perched motionless and silent on the leaves of plants. The post Common tropical bat uses echolocation with precision previously considered impossible, new experiments reveal appeared first on Smithsonian Insider. Full Article Animals Science & Nature animal flight bats insects mammals Tropical Research Institute
pi With no credit to Cupid, white-naped crane couples remain faithful for life By insider.si.edu Published On :: Wed, 13 Feb 2013 14:48:30 +0000 Chris Crowe, keeper of the National Zoo’s 15 white-naped cranes, is well acquainted with the strong attachments these graceful Asian birds form with their mates. The post With no credit to Cupid, white-naped crane couples remain faithful for life appeared first on Smithsonian Insider. Full Article Animals Science & Nature biodiversity birds conservation conservation biology endangered species Migratory Bird Center Smithsonian Conservation Biology Institute Smithsonian's National Zoo
pi Supermassive black hole spins super fast By insider.si.edu Published On :: Wed, 27 Feb 2013 18:12:03 +0000 Imagine a sphere more than 2 million miles across – eight times the distance from Earth to the Moon – spinning so fast that its […] The post Supermassive black hole spins super fast appeared first on Smithsonian Insider. Full Article Science & Nature Space astronomy astrophysics black holes Center for Astrophysics | Harvard & Smithsonian Smithsonian Astrophysical Observatory
pi Six pioneering female scientists you’ve probably never heard of… By insider.si.edu Published On :: Fri, 01 Mar 2013 15:03:50 +0000 March is Women’s History Month and to honor it Smithsonianscience.com presents six images of women scientists selected from the Smithsonian Institution Archvies’s Flicker photoset Women […] The post Six pioneering female scientists you’ve probably never heard of… appeared first on Smithsonian Insider. Full Article Research News Science & Nature
pi Powerful computer simulations show how spiral galaxies get their arms By insider.si.edu Published On :: Wed, 03 Apr 2013 12:25:13 +0000 Spiral galaxies are some of the most beautiful and photogenic residents of the universe. Our own Milky Way is a spiral. Our solar system and […] The post Powerful computer simulations show how spiral galaxies get their arms appeared first on Smithsonian Insider. Full Article Research News Science & Nature Space astronomy astrophysics Center for Astrophysics | Harvard & Smithsonian galaxies Smithsonian Astrophysical Observatory
pi Yellow pigment in penguin feathers is chemically distinct, spectroscopic studies reveal By insider.si.edu Published On :: Mon, 22 Apr 2013 13:06:25 +0000 Recent spectroscopic analysis of macaroni penguin (Eudyptes chrysolophus) crest feathers and king penguin (Aptenodytes patagonicus) neck feathers have shown they contain a yellow pigment that […] The post Yellow pigment in penguin feathers is chemically distinct, spectroscopic studies reveal appeared first on Smithsonian Insider. Full Article Animals Marine Science Research News Science & Nature birds chromatics materials science
pi Mapping Venus with radar By insider.si.edu Published On :: Mon, 18 Nov 2013 16:29:57 +0000 The surface of Venus is hidden beneath a perpetual blanket of clouds, but radar allows scientists at the National Air and Space Museum to […] The post Mapping Venus with radar appeared first on Smithsonian Insider. Full Article Research News Science & Nature Space Spotlight astronomy astrophysics Center for Earth and Planetary Studies National Air and Space Museum planets rocks & minerals
pi Penis spines help scientists identify bat species By insider.si.edu Published On :: Thu, 03 Apr 2014 11:00:14 +0000 Sometimes you need to look in unusual places to tell species apart. Some mammal species are easily distinguished by differences in their fur or skeletons, […] The post Penis spines help scientists identify bat species appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature bats conservation biology fungi mammals National Museum of Natural History
pi Commercial shipping lanes changed in Panama to save humpback whales By insider.si.edu Published On :: Wed, 28 May 2014 19:07:39 +0000 The Republic of Panama’s proposal to implement four Traffic Separation Schemes for commercial vessels entering and exiting the Panama Canal and ports was approved unanimously […] The post Commercial shipping lanes changed in Panama to save humpback whales appeared first on Smithsonian Insider. Full Article Marine Science Research News Science & Nature Colombia conservation conservation biology Ecuador endangered species South America Tropical Research Institute whales
pi Feathers yield mysteries of pigment chemistry to spectroscopic analysis By insider.si.edu Published On :: Fri, 30 May 2014 18:37:21 +0000 A research team from the Smithsonian and Arizona State University have developed a new, non-destructive method using spectroscopic analysis to help unravel the complex chemistry […] The post Feathers yield mysteries of pigment chemistry to spectroscopic analysis appeared first on Smithsonian Insider. Full Article Research News Science & Nature birds chromatics endangered species materials science National Museum of Natural History
pi Smithsonian scientists discover tropical tree microbiome in Panama By insider.si.edu Published On :: Tue, 16 Sep 2014 14:05:57 +0000 Human skin and gut microbes influence processes from digestion to disease resistance. Despite the fact that tropical forests are the most biodiverse terrestrial ecosystems on […] The post Smithsonian scientists discover tropical tree microbiome in Panama appeared first on Smithsonian Insider. Full Article Research News Science & Nature Center for Tropical Forest Science conservation biology Forest Global Earth Observatory
pi What is that?! Five Amazing Microscopic Images By insider.si.edu Published On :: Wed, 22 Oct 2014 15:00:09 +0000 From bizarre bugs to penis spines on bats, our world is infinitely expanded when we look down the microscope! Check out the stories behind these […] The post What is that?! Five Amazing Microscopic Images appeared first on Smithsonian Insider. Full Article Animals Science & Nature ants bats fungi insects spiders
pi Eight strange but true spider facts By insider.si.edu Published On :: Fri, 28 Nov 2014 11:03:27 +0000 1. Some male spiders just want to be eaten Black widows are known for cannibalizing their mates, but this doesn’t actually happen all the time. […] The post Eight strange but true spider facts appeared first on Smithsonian Insider. Full Article Animals Science & Nature insects Smithsonian's National Zoo spiders
pi Keeping Warm in Winter is for the Birds By insider.si.edu Published On :: Fri, 30 Jan 2015 14:25:12 +0000 You watch the weather forecast, gear up with hat, coat, scarf and gloves, but you still get cold after just a short time in the […] The post Keeping Warm in Winter is for the Birds appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature birds conservation biology Migratory Bird Center Smithsonian's National Zoo
pi Geologic Mapping of Mars By insider.si.edu Published On :: Thu, 28 May 2015 16:39:14 +0000 Geologic mapping is an integral part of exploration and understanding a planetary landscape, because it shows the relationships between geologic units and helps delineate the […] The post Geologic Mapping of Mars appeared first on Smithsonian Insider. Full Article Research News Science & Nature Space Spotlight astronomy astrophysics geology National Air and Space Museum
pi Digitized, Searchable Archives Help Revive ‘Sleeping’ Languages By insider.si.edu Published On :: Thu, 23 Jul 2015 13:16:43 +0000 Like other kids at summer camp, a group of youngsters in the cities of Miami, Okla. and Fort Wayne, Ind. play games, work on crafts […] The post Digitized, Searchable Archives Help Revive ‘Sleeping’ Languages appeared first on Smithsonian Insider. Full Article Anthropology Research News Science & Nature digitization National Museum of Natural History technology
pi Colorful Caterpillar Chemists By insider.si.edu Published On :: Thu, 08 Oct 2015 13:01:11 +0000 Scientists at the Smithsonian Tropical Research Institute (STRI) in Panama compared the diets of two caterpillar species, expecting the one that exclusively consumed plants containing […] The post Colorful Caterpillar Chemists appeared first on Smithsonian Insider. Full Article Research News Science & Nature Spotlight chromatics conservation biology insects Tropical Research Institute
pi Fossils help scientists build a picture of the past—and present By insider.si.edu Published On :: Thu, 08 Oct 2015 23:13:20 +0000 A word to the wise: don’t ask a paleontologist to pick a favorite fossil. It’s like asking your mother which child she loves most, or […] The post Fossils help scientists build a picture of the past—and present appeared first on Smithsonian Insider. Full Article Animals Dinosaurs & Fossils Marine Science Science & Nature biodiversity carbon dioxide climate change conservation extinction fossils geology National Museum of Natural History
pi Survey pinpoints where toxic mercury accumulates in world environments By insider.si.edu Published On :: Fri, 09 Oct 2015 18:02:40 +0000 Here’s some good news that should hit you in the gut. A team of scientists searching thousands of environments for bacteria that produce the deadly […] The post Survey pinpoints where toxic mercury accumulates in world environments appeared first on Smithsonian Insider. Full Article Animals Marine Science Research News Science & Nature amphibian biodiversity birds conservation biology fishes Smithsonian Environmental Research Center
pi Study reveals ancient link between mammoth dung and pumpkin pie By insider.si.edu Published On :: Mon, 23 Nov 2015 18:16:53 +0000 New research by a team of archaeologists has revealed a curious connection between our traditional Thanksgiving dinner and the taste buds of prehistoric mammoths and […] The post Study reveals ancient link between mammoth dung and pumpkin pie appeared first on Smithsonian Insider. Full Article Anthropology Dinosaurs & Fossils Research News Science & Nature archaeology conservation biology extinction National Museum of Natural History
pi Smithsonian-Cornell Partnership produces First Domestic Puppies by In Vitro Fertilization By insider.si.edu Published On :: Wed, 09 Dec 2015 16:00:32 +0000 After decades of attempts, Smithsonian Conservation Biology Institute (SCBI) scientists and researchers at Cornell University have become the first to successfully use in vitro fertilization […] The post Smithsonian-Cornell Partnership produces First Domestic Puppies by In Vitro Fertilization appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature conservation conservation biology endangered species mammals Smithsonian Conservation Biology Institute Smithsonian's National Zoo technology
pi Carotenoid pigments make extinct duck a rare bird indeed By insider.si.edu Published On :: Mon, 07 Mar 2016 13:50:22 +0000 The pink-headed duck was no lucky duck. In 1948 a single specimen of this waterfowl, Rhodonessa caryophyllacea, was donated to the Division of Birds of […] The post Carotenoid pigments make extinct duck a rare bird indeed appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature biodiversity birds chromatics conservation biology extinction National Museum of Natural History
pi Discovery: trap-jaw spiders snap prey with super-spidey speed and power By insider.si.edu Published On :: Thu, 07 Apr 2016 16:01:51 +0000 New high-speed videos of 14 species of tiny Mecysmaucheniid “trap-jaw” spiders have revealed that some species can snap their mouth parts shut at incredibly fast […] The post Discovery: trap-jaw spiders snap prey with super-spidey speed and power appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature Spotlight insects National Museum of Natural History spiders
pi New bright orange-red scorpionfish discovered deep in Caribbean By insider.si.edu Published On :: Mon, 25 Jul 2016 14:57:04 +0000 Meet Scorpaenodes barrybrowni is a scorpionfish species newly discovered by Smithsonian scientists using a manned submersible in the deep-reef waters of the Caribbean island of Curaçao. It […] The post New bright orange-red scorpionfish discovered deep in Caribbean appeared first on Smithsonian Insider. Full Article Animals Marine Science Research News Science & Nature Spotlight conservation biology fishes National Museum of Natural History new species Tropical Research Institute
pi By simply pooping, comb jellies expel long-held scientific misconception By insider.si.edu Published On :: Mon, 28 Nov 2016 18:58:16 +0000 In 2012, under a scientist’s watchful eye, a comb jelly ate some fish, digested it, and excreted the waste out its back end. In doing […] The post By simply pooping, comb jellies expel long-held scientific misconception appeared first on Smithsonian Insider. Full Article Animals Marine Science Research News Science & Nature National Museum of Natural History
pi Snow puppies By insider.si.edu Published On :: Fri, 16 Dec 2016 13:15:50 +0000 Perhaps puppies cuddling in the snow makes winter’s bite not so unpleasant? In one of his most charming designs, Japanese artist Isoda Koryūsai (1735–1790) depicted […] The post Snow puppies appeared first on Smithsonian Insider. Full Article Animals Art History & Culture Science & Nature Snapshot
pi Our Galaxy’s Black Hole is Spewing Planet-size “Spitballs” By insider.si.edu Published On :: Fri, 06 Jan 2017 19:56:12 +0000 Every few thousand years, an unlucky star wanders too close to the black hole at the center of the Milky Way. The black hole’s powerful […] The post Our Galaxy’s Black Hole is Spewing Planet-size “Spitballs” appeared first on Smithsonian Insider. Full Article Science & Nature Space Center for Astrophysics | Harvard & Smithsonian Milky Way Smithsonian Astrophysical Observatory
pi Odd anatomy: flexible joint between skull and spine allow dragonfish to open wide By insider.si.edu Published On :: Wed, 01 Feb 2017 22:09:39 +0000 Food is scarce in the deep, dark regions of the ocean where barbeled dragonfishes and their relatives dwell. Known as the Stomiidae, some of these […] The post Odd anatomy: flexible joint between skull and spine allow dragonfish to open wide appeared first on Smithsonian Insider. Full Article Animals Marine Science Research News Science & Nature fishes National Museum of Natural History
pi Keeping Track of Kirtland’s Warbler All Year Long―A Scientific First By insider.si.edu Published On :: Thu, 02 Mar 2017 15:00:20 +0000 To fully know a species and develop sound conservation efforts, its full life cycle must be understood. But tracking small migratory birds for thousands of […] The post Keeping Track of Kirtland’s Warbler All Year Long―A Scientific First appeared first on Smithsonian Insider. Full Article Animals Science & Nature birds conservation biology Migratory Bird Center Smithsonian Conservation Biology Institute Smithsonian's National Zoo
pi 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
pi Indestructible jaws from ancient, extinct porcupine fish reveal new species By insider.si.edu Published On :: Thu, 17 Aug 2017 15:20:36 +0000 Covered in sharp spines, when harassed the porcupine fish inflates like a balloon. Think of a small soccer ball bristling all over with nails. Most predators […] The post Indestructible jaws from ancient, extinct porcupine fish reveal new species appeared first on Smithsonian Insider. Full Article Animals Dinosaurs & Fossils Marine Science Science & Nature National Museum of Natural History new species Smithsonian Tropical Research Institute
pi Locked and loaded: unique trigger design fires this ant’s snapping jaws By insider.si.edu Published On :: Thu, 31 Aug 2017 12:08:54 +0000 In conflicts between predators and prey, speed is a decided advantage, and evolution has given the trap-jaw ant a distinct advantage with spring-loaded jaws that […] The post Locked and loaded: unique trigger design fires this ant’s snapping jaws appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature insects National Museum of Natural History spiders
pi These newly discovered pelican spiders will make you want to visit Madagascar By insider.si.edu Published On :: Thu, 11 Jan 2018 18:15:20 +0000 In 1854, a curious-looking spider was found preserved in 50 million-year-old amber. With an elongated neck-like structure and long mouthparts that protruded from the “head” […] The post These newly discovered pelican spiders will make you want to visit Madagascar appeared first on Smithsonian Insider. Full Article Animals Science & Nature National Museum of Natural History
pi More sky puppies! Scientists discover two new species of dog-faced bat By insider.si.edu Published On :: Mon, 15 Jan 2018 16:33:57 +0000 Flitting swiftly through the darkness above the tropical forest canopy in Central and South America, a group of cute little bats with dog-like faces have […] The post More sky puppies! Scientists discover two new species of dog-faced bat appeared first on Smithsonian Insider. Full Article Animals Research News Science & Nature bats mammals National Museum of Natural History new species Smithsonian Tropical Research Institute
pi 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
pi STRIPAK-PP2A regulates Hippo-Yorkie signaling to suppress retinal fate in the Drosophila eye disc peripodial epithelium [RESEARCH ARTICLE] By jcs.biologists.org Published On :: 2020-03-17T03:51:28-07:00 Scott J. Neal, Qingxiang Zhou, and Francesca PignoniThe specification of organs, tissues and cell types results from cell fate restrictions enacted by nuclear transcription factors under the control of conserved signaling pathways. The progenitor epithelium of the Drosophila compound eye, the eye imaginal disc, is a premier model for the study of such processes. Early in development, apposing cells of the eye disc are established as either retinal progenitors or support cells of the peripodial epithelium (PE), in a process whose genetic and mechanistic determinants are poorly understood. We have identified Protein Phosphatase 2A (PP2A), and specifically a STRIPAK-PP2A complex that includes the scaffolding and substrate-specificity components Cka, Strip and SLMAP, as a critical player in the retina-PE fate choice. We show that these factors suppress ectopic retina formation in the presumptive PE and do so via the Hippo signaling axis. STRIPAK-PP2A negatively regulates Hpo kinase, and consequently its substrate Wts, to release the transcriptional co-activator Yki into the nucleus. Thus, a modular higher-order PP2A complex refines the activity of this general phosphatase to act in a precise specification of cell fate. Full Article
pi 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
pi F-BAR domain protein Syndapin regulates actomyosin dynamics during apical cap remodeling in syncytial Drosophila embryos [SHORT REPORT] By jcs.biologists.org Published On :: 2020-04-23T01:49:49-07:00 Aparna Sherlekar, Gayatri Mundhe, Prachi Richa, Bipasha Dey, Swati Sharma, and Richa RikhyBranched actin networks driven by Arp2/3 collaborate with actomyosin filaments in processes such as cell migration. The syncytial Drosophila blastoderm embryo also shows expansion of apical caps by Arp2/3 driven actin polymerization in interphase and buckling at contact edges by MyosinII to form furrows in metaphase. Here we study the role of Syndapin (Synd), an F-BAR domain containing protein in apical cap remodelling prior to furrow extension. synd depletion showed larger apical caps. STED super-resolution and TIRF microscopy showed long apical actin protrusions in caps in interphase and short protrusions in metaphase in control embryos. synd depletion led to sustained long protrusions even in metaphase. Loss of Arp2/3 function in synd mutants partly reverted defects in apical cap expansion and protrusion remodelling. MyosinII levels were decreased in synd mutants and MyosinII mutant embryos have been previously reported to have expanded caps. We propose that Syndapin function limits branching activity during cap expansion and affects MyosinII distribution in order to shift actin remodeling from apical cap expansion to favor lateral furrow extension. Full Article
pi 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
pi 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