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  • 1
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    Two insulin receptors determine alternative wing morphs in planthoppers (2015)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2015-03-25
    Description: Wing polyphenism is an evolutionarily successful feature found in a wide range of insects. Long-winged morphs can fly, which allows them to escape adverse habitats and track changing resources, whereas short-winged morphs are flightless, but usually possess higher fecundity than the winged morphs. Studies on aphids, crickets and planthoppers have revealed that alternative wing morphs develop in response to various environmental cues, and that the response to these cues may be mediated by developmental hormones, although research in this area has yielded equivocal and conflicting results about exactly which hormones are involved. As it stands, the molecular mechanism underlying wing morph determination in insects has remained elusive. Here we show that two insulin receptors in the migratory brown planthopper Nilaparvata lugens, InR1 and InR2, have opposing roles in controlling long wing versus short wing development by regulating the activity of the forkhead transcription factor Foxo. InR1, acting via the phosphatidylinositol-3-OH kinase (PI(3)K)-protein kinase B (Akt) signalling cascade, leads to the long-winged morph if active and the short-winged morph if inactive. InR2, by contrast, functions as a negative regulator of the InR1-PI(3)K-Akt pathway: suppression of InR2 results in development of the long-winged morph. The brain-secreted ligand Ilp3 triggers development of long-winged morphs. Our findings provide the first evidence of a molecular basis for the regulation of wing polyphenism in insects, and they are also the first demonstration--to our knowledge--of binary control over alternative developmental outcomes, and thus deepen our understanding of the development and evolution of phenotypic plasticity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Xu, Hai-Jun -- Xue, Jian -- Lu, Bo -- Zhang, Xue-Chao -- Zhuo, Ji-Chong -- He, Shu-Fang -- Ma, Xiao-Fang -- Jiang, Ya-Qin -- Fan, Hai-Wei -- Xu, Ji-Yu -- Ye, Yu-Xuan -- Pan, Peng-Lu -- Li, Qiao -- Bao, Yan-Yuan -- Nijhout, H Frederik -- Zhang, Chuan-Xi -- England -- Nature. 2015 Mar 26;519(7544):464-7. doi: 10.1038/nature14286. Epub 2015 Mar 18.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Agricultural Entomology, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China. ; Department of Biology, Duke University, Durham, North Carolina 27708, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25799997" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Female ; Forkhead Transcription Factors/deficiency/metabolism ; Hemiptera/*anatomy & histology/enzymology/genetics/*metabolism ; Insulin/metabolism ; Male ; Molecular Sequence Data ; Phosphatidylinositol 3-Kinases/metabolism ; Proto-Oncogene Proteins c-akt/metabolism ; Receptor, Insulin/deficiency/*metabolism ; Signal Transduction ; Wings, Animal/anatomy & histology/enzymology/*growth & development/*metabolism
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 2
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    Efficient Construction of CCA-Secure Threshold PKE Based on Hashed Diffie-Hellman Assumption (2013)
    Oxford University Press
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    Publication Date: 2013-10-02
    Description: In threshold public-key encryption (TPKE), the decryption key is divided into n shares, each one of which is given to a different decryption user in order to avoid single points of failure. A robust TPKE is that if threshold decryption of a valid ciphertext fails, the combiner can identify the decryption users that supplied invalid partial decryption shares. In this paper, we propose a practical and efficient TPKE scheme which is robust and non-interactive. Security against chosen-ciphertext attacks (CCAs) can be proved in the standard model under the hashed Diffie–Hellman assumption in bilinear groups. The security reduction is tight and simple. We use an instantiation hash function of the Kiltz's key encapsulation mechanism and Lai et al. 's chosen-ciphertext secure technique to construct a TPKE scheme. Moreover, our scheme is more simple and shown to be more efficient than currently existing CCA-secure TPKE schemes.
    Print ISSN: 0010-4620
    Electronic ISSN: 1460-2067
    Topics: Computer Science
    Published by Oxford University Press
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  • 3
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    Transport pathways and signatures of mixing in the extratropical tropopause region derived from Lagrangian model simulations (2011)
    Wiley
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    Publication Date: 2011-03-15
    Description: Model simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS) driven by wind fields of the National Center for Environmental Prediction (NCEP) were performed in the midlatitude tropopause region in April 2008 to study two research flights conducted during the START08 campaign. One flight targeted a deep tropospheric intrusion and another flight targeted a deep stratospheric intrusion event, both of them in the vicinity of the subtropical and polar jet. Air masses with strong signatures of mixing between stratospheric and tropospheric air masses were identified from measured CO-O3 correlations, and the characteristics were reproduced by CLaMS model simulations. CLaMS simulations in turn complement the observations and provide a broader view of the mixed region in physical space. Using artificial tracers of air mass origin within CLaMS yields unique information about the transport pathways and their contribution to the composition in the mixed region from different transport origins. Three different regions are examined to categorize dominant transport processes: (1) on the cyclonic side of the polar jet within tropopause folds where air from the lowermost stratosphere and the cyclonic side of the jet is transported downward into the troposphere, (2) on the anticyclonic side of the polar jet around the 2 PVU surface air masses, where signatures of mixing between the troposphere and lowermost stratosphere were found with large contributions of air masses from low latitudes, and (3) in the lower stratosphere associated with a deep tropospheric intrusion originating in the tropical tropopause layer (TTL). Moreover, the time scale of transport from the TTL into the lowermost stratosphere is in the range of weeks whereas the stratospheric intrusions occur on a time scale of days.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 4
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    Chemical and dynamical discontinuity at the extratropical tropopause based on START08 and WACCM analyses (2011)
    Wiley
    Details
    Publication Date: 2011-12-17
    Description: Using isentropic trace gas gradients of O3 and CO, the discontinuity in the chemical composition of the upper troposphere (UT) and lower stratosphere (LS) is examined on middle world isentropes from 300 to 380 K. The analysis is a follow-up study of the dynamical discontinuity as represented by the potential vorticity (PV) gradient-based tropopause, which is based on the product of isentropic PV gradients and wind speed. Overall, there is fairly good consistency between the chemical discontinuity in trace gas distributions and the PV gradient-based tropopause. Trace gas gradients at the PV gradient-based tropopause are stronger in winter than in summer, revealing the seasonal cycle of the tropopause transport barrier. The analysis of the trace gas gradients also identifies atmospheric transport pathways in the upper troposphere–lower stratosphere (UTLS). Several regions where trace gas gradients are found to be decoupled from the dynamical field indicate preferred transport pathways between the UT and LS. In particular, anomalous CO and O3 gradients above eastern Africa, eastern Asia, and the West Pacific are likely related to convective transport, and anomalous O3 gradients over the North Atlantic and North Pacific are related to isentropic transport connected to frequent wave breaking. The results indicate that the PV gradient-based tropopause definition provides a good identification of the dynamical and chemical discontinuity and is therefore effective in locating the physical boundary in the UTLS.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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