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Private asteroid hunt lacks cash to spy threats in orbit

Nature - Fri, 06/19/2015 - 00:00

Private asteroid hunt lacks cash to spy threats in orbit

Nature 522, 7557 (2015). http://www.nature.com/doifinder/10.1038/522402a

Author: Traci Watson

Foundation fails to raise funds it needs for a space telescope to catalogue near-Earth objects.

Categories: Literature

Pope Calls for Global Action on Climate Change and Environmental Problems

Yale Environment 360 - Thu, 06/18/2015 - 10:23

Pope Francis released today his highly anticipated encyclical, which is largely focused on halting climate change and

Pope Francis environmental degradation and emphasizes the importance of protecting impoverished communities from the worst effects. This is the first such letter from a leader of the Catholic Church to address environmental issues, analysts say. “Climate change is a global problem with grave implications: environmental, social, economic, political,” Pope Francis wrote. “It represents one of the principal challenges facing humanity in our day.” Industrialized countries are responsible for most of the damage, he said, and are obligated to help developing nations cope with the looming crisis. Within the document, he delves deeply into both climate science and economic development policies, and chides climate change skeptics for their "denial."

Categories: Environmental News

A Little Fish with Big Impact In Trouble on U.S. West Coast

Yale Environment 360 - Thu, 06/18/2015 - 07:31

Scientists are concerned that officials waited too long to order a ban on U.S. Pacific sardine fishing that goes into effect July 1. The dire state of the sardine population is a cautionary tale about overharvesting these and other forage fish that are a critical part of the marine food web. BY ELIZABETH GROSSMAN

Categories: Environmental News

Astronomers claim first glimpse of primordial stars

Nature - Thu, 06/18/2015 - 00:00

Astronomers claim first glimpse of primordial stars

Nature 522, 7557 (2015). http://www.nature.com/doifinder/10.1038/nature.2015.17802

Author: Elizabeth Gibney

Bright galaxy thought to hold stars from generation that seeded rest of Universe.

Categories: Literature

Ancient American genome rekindles legal row

Nature - Thu, 06/18/2015 - 00:00

Ancient American genome rekindles legal row

Nature 522, 7557 (2015). http://www.nature.com/doifinder/10.1038/nature.2015.17797

Author: Ewen Callaway

'Kennewick Man' sequencing points to Native American ancestry.

Categories: Literature

Harnessing Evaporation Could Yield More Power than Wind, Study Shows

Yale Environment 360 - Wed, 06/17/2015 - 11:18

Using the energy produced by evaporating water, researchers at Columbia University have shown that they can

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A miniature car driven by evaporation. power a small toy car and a flashing light — the first step, they say, in harnessing an immense energy source that could rival power production from wind and waves. The devices they built use bacterial spores that can absorb humidity and, in doing so, expand and contract with enough force to push and pull pistons and drive a rotary engine. The spores pack more energy, pound for pound, than other materials used in engineering for moving objects, said researcher Ozgur Sahin, who co-authored the study published in Nature Communication. When evaporation energy is scaled up, he says, it could one day produce electricity from giant floating power generators that sit on bays or reservoirs or rotating machines like wind turbines that sit above water.

Categories: Environmental News

Interview: Is Reviving Mammoths Science Fiction or a Conservation Tool?

Yale Environment 360 - Wed, 06/17/2015 - 07:34

Biologist Beth Shapiro has published a new book, How to Clone a Mammoth, that looks at the many Beth Shapiro questions — both technical and ethical — surrounding any attempt to revive extinct species. In a Yale Environment 360 interview, Shapiro, associate director of the Paleogenomics Institute at the University of California at Santa Cruz, explains why she believes new gene-editing technology could benefit critical ecosystems and living species that are now endangered. “We are in the midst of an extinction crisis,” she says. “Why would we not use whatever technologies are available to us, assuming we can go about doing it in a reasonable and ethical way?”
Read the interview.

Categories: Environmental News

Spatiotemporal control of a novel synaptic organizer molecule

Nature - Wed, 06/17/2015 - 00:00

Spatiotemporal control of a novel synaptic organizer molecule

Nature 523, 7558 (2015). doi:10.1038/nature14545

Authors: Kelly Howell, John G. White & Oliver Hobert

Synapse formation is a process tightly controlled in space and time. How gene regulatory mechanisms specify spatial and temporal aspects of synapse formation is not well understood. In the nematode Caenorhabditis elegans, two subtypes of the D-type inhibitory motor neuron (MN) classes, the dorsal D (DD) and ventral D (VD) neurons, extend axons along both the dorsal and ventral nerve cords. The embryonically generated DD motor neurons initially innervate ventral muscles in the first (L1) larval stage and receive their synaptic input from cholinergic motor neurons in the dorsal cord. They rewire by the end of the L1 moult to innervate dorsal muscles and to be innervated by newly formed ventral cholinergic motor neurons. VD motor neurons develop after the L1 moult; they take over the innervation of ventral muscles and receive their synaptic input from dorsal cholinergic motor neurons. We show here that the spatiotemporal control of synaptic wiring of the D-type neurons is controlled by an intersectional transcriptional strategy in which the UNC-30 Pitx-type homeodomain transcription factor acts together, in embryonic and early larval stages, with the temporally controlled LIN-14 transcription factor to prevent premature synapse rewiring of the DD motor neurons and, together with the UNC-55 nuclear hormone receptor, to prevent aberrant VD synaptic wiring in later larval and adult stages. A key effector of this intersectional transcription factor combination is a novel synaptic organizer molecule, the single immunoglobulin domain protein OIG-1. OIG-1 is perisynaptically localized along the synaptic outputs of the D-type motor neurons in a temporally controlled manner and is required for appropriate selection of both pre- and post-synaptic partners.

Categories: Literature

Plant science: Precision positioning with peptides

Nature - Wed, 06/17/2015 - 00:00

Plant science: Precision positioning with peptides

Nature 522, 7557 (2015). doi:10.1038/nature14535

Authors: Sacco de Vries

Two related peptides compete for binding to the same receptor to regulate the spacing of cells on the lower surfaces of leaves. This discovery highlights the complexity of cell signalling in plants. See Article p.439

Categories: Literature

Biochemistry: Unexpected role for vitamin B2

Nature - Wed, 06/17/2015 - 00:00

Biochemistry: Unexpected role for vitamin B2

Nature 522, 7557 (2015). doi:10.1038/nature14536

Authors: Catherine F. Clarke & Christopher M. Allan

An enzyme has been found that alters the molecular structure of vitamin B2, adding a fourth ring to its existing three-ring system. The product catalyses new types of chemistry in concert with certain other enzymes. See Letters p.497 & p.502

Categories: Literature

Competitive binding of antagonistic peptides fine-tunes stomatal patterning

Nature - Wed, 06/17/2015 - 00:00

Competitive binding of antagonistic peptides fine-tunes stomatal patterning

Nature 522, 7557 (2015). doi:10.1038/nature14561

Authors: Jin Suk Lee, Marketa Hnilova, Michal Maes, Ya-Chen Lisa Lin, Aarthi Putarjunan, Soon-Ki Han, Julian Avila & Keiko U. Torii

During development, cells interpret complex and often conflicting signals to make optimal decisions. Plant stomata, the cellular interface between a plant and the atmosphere, develop according to positional cues, which include a family of secreted peptides called epidermal patterning factors (EPFs). How these signalling peptides

Categories: Literature

HIF-driven SF3B1 induces KHK-C to enforce fructolysis and heart disease

Nature - Wed, 06/17/2015 - 00:00

HIF-driven SF3B1 induces KHK-C to enforce fructolysis and heart disease

Nature 522, 7557 (2015). doi:10.1038/nature14508

Authors: Peter Mirtschink, Jaya Krishnan, Fiona Grimm, Alexandre Sarre, Manuel Hörl, Melis Kayikci, Niklaus Fankhauser, Yann Christinat, Cédric Cortijo, Owen Feehan, Ana Vukolic, Samuel Sossalla, Sebastian N. Stehr, Jernej Ule, Nicola Zamboni, Thierry Pedrazzini & Wilhelm Krek

Fructose is a major component of dietary sugar and its overconsumption exacerbates key pathological features of metabolic syndrome. The central fructose-metabolising enzyme is ketohexokinase (KHK), which exists in two isoforms: KHK-A and KHK-C, generated through mutually exclusive alternative splicing of KHK pre-mRNAs. KHK-C displays

Categories: Literature

New cofactor supports α,β-unsaturated acid decarboxylation via 1,3-dipolar cycloaddition

Nature - Wed, 06/17/2015 - 00:00

New cofactor supports α,β-unsaturated acid decarboxylation via 1,3-dipolar cycloaddition

Nature 522, 7557 (2015). doi:10.1038/nature14560

Authors: Karl A. P. Payne, Mark D. White, Karl Fisher, Basile Khara, Samuel S. Bailey, David Parker, Nicholas J. W. Rattray, Drupad K. Trivedi, Royston Goodacre, Rebecca Beveridge, Perdita Barran, Stephen E. J. Rigby, Nigel S. Scrutton, Sam Hay & David Leys

The bacterial ubiD and ubiX or the homologous fungal fdc1 and pad1 genes have been implicated in the non-oxidative reversible decarboxylation of aromatic substrates, and play a pivotal role in bacterial ubiquinone (also known as coenzyme Q) biosynthesis or microbial biodegradation of aromatic compounds, respectively. Despite biochemical studies on individual gene products, the composition and cofactor requirement of the enzyme responsible for in vivo decarboxylase activity remained unclear. Here we show that Fdc1 is solely responsible for the reversible decarboxylase activity, and that it requires a new type of cofactor: a prenylated flavin synthesized by the associated UbiX/Pad1. Atomic resolution crystal structures reveal that two distinct isomers of the oxidized cofactor can be observed, an isoalloxazine N5-iminium adduct and a N5 secondary ketimine species with markedly altered ring structure, both having azomethine ylide character. Substrate binding positions the dipolarophile enoic acid group directly above the azomethine ylide group. The structure of a covalent inhibitor–cofactor adduct suggests that 1,3-dipolar cycloaddition chemistry supports reversible decarboxylation in these enzymes. Although 1,3-dipolar cycloaddition is commonly used in organic chemistry, we propose that this presents the first example, to our knowledge, of an enzymatic 1,3-dipolar cycloaddition reaction. Our model for Fdc1/UbiD catalysis offers new routes in alkene hydrocarbon production or aryl (de)carboxylation.

Categories: Literature

UbiX is a flavin prenyltransferase required for bacterial ubiquinone biosynthesis

Nature - Wed, 06/17/2015 - 00:00

UbiX is a flavin prenyltransferase required for bacterial ubiquinone biosynthesis

Nature 522, 7557 (2015). doi:10.1038/nature14559

Authors: Mark D. White, Karl A. P. Payne, Karl Fisher, Stephen A. Marshall, David Parker, Nicholas J. W. Rattray, Drupad K. Trivedi, Royston Goodacre, Stephen E. J. Rigby, Nigel S. Scrutton, Sam Hay & David Leys

Ubiquinone (also known as coenzyme Q) is a ubiquitous lipid-soluble redox cofactor that is an essential component of electron transfer chains. Eleven genes have been implicated in bacterial ubiquinone biosynthesis, including ubiX and ubiD, which are responsible for decarboxylation of the 3-octaprenyl-4-hydroxybenzoate precursor. Despite structural and biochemical characterization of UbiX as a flavin mononucleotide (FMN)-binding protein, no decarboxylase activity has been detected. Here we report that UbiX produces a novel flavin-derived cofactor required for the decarboxylase activity of UbiD. UbiX acts as a flavin prenyltransferase, linking a dimethylallyl moiety to the flavin N5 and C6 atoms. This adds a fourth non-aromatic ring to the flavin isoalloxazine group. In contrast to other prenyltransferases, UbiX is metal-independent and requires dimethylallyl-monophosphate as substrate. Kinetic crystallography reveals that the prenyltransferase mechanism of UbiX resembles that of the terpene synthases. The active site environment is dominated by π systems, which assist phosphate-C1′ bond breakage following FMN reduction, leading to formation of the N5–C1′ bond. UbiX then acts as a chaperone for adduct reorientation, via transient carbocation species, leading ultimately to formation of the dimethylallyl C3′–C6 bond. Our findings establish the mechanism for formation of a new flavin-derived cofactor, extending both flavin and terpenoid biochemical repertoires.

Categories: Literature

Risky business

Nature - Wed, 06/17/2015 - 00:00

Risky business

Nature 522, 7556 (2015). doi:10.1038/522256a

Funding agencies should highlight their roles as risk managers to underpin public trust.

Categories: Literature

Rethink our approach to assessing risk

Nature - Wed, 06/17/2015 - 00:00

Rethink our approach to assessing risk

Nature 522, 7556 (2015). http://www.nature.com/doifinder/10.1038/522257a

Author: Frederick Grinnell

The ‘post-normal science’ framework would make regulatory decisions about research in humans more effective, says Frederick Grinnell.

Categories: Literature

Hydrology: Floods used as defensive weapons

Nature - Wed, 06/17/2015 - 00:00

Hydrology: Floods used as defensive weapons

Nature 522, 7556 (2015). doi:10.1038/522258a

One-third of all major floods recorded in the Netherlands over the past 500 years were caused deliberately by humans to defend the territory during wartime.Adriaan de Kraker of Free University Amsterdam trawled historical maps, land ownership documents and written accounts of flooding events in

Categories: Literature

Primatology: Chimps are not averse to alcohol

Nature - Wed, 06/17/2015 - 00:00

Primatology: Chimps are not averse to alcohol

Nature 522, 7556 (2015). doi:10.1038/522258b

Chimpanzees at a site in West Africa drink alcohol-containing sap from raffia trees — the first systematic evidence that non-human apes ingest naturally fermented food in the wild.In Guinea, local people collect this sap by hanging containers under holes tapped near the crowns of

Categories: Literature

Zoology: Cuckoo finch is a master of mimicry

Nature - Wed, 06/17/2015 - 00:00

Zoology: Cuckoo finch is a master of mimicry

Nature 522, 7556 (2015). doi:10.1038/522258c

Some birds use other species' nests to lay eggs that resemble those of the other species, escaping the burdens of parenthood. Now researchers have found a type of finch in Africa that also mimics how another bird looks as an adult.The female cuckoo finch

Categories: Literature

Optics: Graphene shines bright in a vacuum

Nature - Wed, 06/17/2015 - 00:00

Optics: Graphene shines bright in a vacuum

Nature 522, 7556 (2015). doi:10.1038/522258d

Physicists have designed a 2D device that can emit bright, visible light, paving the way for ultra-thin light-emitting devices.One-atom-thick layers of carbon called graphene can withstand the high temperatures at which they emit light. But when graphene is stuck to a surface and electricity

Categories: Literature

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