4,382 research outputs found

    Varroakvalstrets effekt pÄ virus i angripna honungsbisamhÀllen

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    Vilken effekt har varroakvalster pÄ de virus som infekterar bisamhÀllen? Forskare vid INRA (Frankrikes nationella institution för jordbruksforskning) i Avignon, Frankrike, University of Otago i Nya Zeeland och Sveriges lantbruksuniversitet (SLU), nyttjade en unik situation i Nya Zeeland dÀr landet, liksom Sverige, har varroaangripna respektive icke angripna regioner. Varroa Àr relativt nyetablerad i Nya Zeeland. Den pÄvisades först pÄ Nordön Är 2000, och har stadigt spridits söderut under de 14 Ären som gÄtt sedan introduktionen. Forskarna har undersökt virusprofilen hos bisamhÀllena sedan etablering av kvalstret i de olika regionerna. Studien, som publicerades 2014, visar en drastisk Àndring av det virala landskapet i bisamhÀllena som sammanfaller med etablering av varroa, vilket ökar risken för synergier mellan olika virus som Àr skadliga för bina

    E-ÎČ-Ocimene, a Volatile Brood Pheromone Involved in Social Regulation in the Honey Bee Colony (Apis mellifera)

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    Background: In honey bee colony, the brood is able to manipulate and chemically control the workers in order to sustain their own development. A brood ester pheromone produced primarily by old larvae (4 and 5 days old larvae) was first identified as acting as a contact pheromone with specific effects on nurses in the colony. More recently a new volatile brood pheromone has been identified: E-ÎČ-ocimene, which partially inhibits ovary development in workers. [br/] Methodology and Principal Finding: Our analysis of E-ÎČ-ocimene production revealed that young brood (newly hatched to 3 days old) produce the highest quantity of E-b-ocimene relative to their body weight. By testing the potential action of this molecule as a non-specific larval signal, due to its high volatility in the colony, we demonstrated that in the presence of E-ÎČ-ocimene nest workers start to forage earlier in life, as seen in the presence of real brood. [br/] Conclusions/Significance: In this way, young larvae are able to assign precedence to the task of foraging by workers in order to increase food stores for their own development. Thus, in the complexity of honey bee chemical communication, E-ÎČ- ocimene, a pheromone of young larvae, provides the brood with the means to express their nutritional needs to the workers

    Intrabeam scattering analysis of measurements at KEK's ATF damping ring

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    We derive a simple relation for estimating the relative emittance growth in x and y due to intrabeam scattering (IBS) in electron storage rings. We show that IBS calculations for the ATF damping ring, when using the formalism of Bjorken-Mtingwa, a modified formalism of Piwinski (where eta squared divided by beta has been replaced by the dispersion invariant), or a simple high-energy approximate formula all give results that agree well. Comparing theory, including the effect of potential well bunch lengthening, with a complete set of ATF steady-state beam size vs. current measurements we find reasonably good agreement for energy spread and horizontal emittance. The measured vertical emittance, however, is larger than theory in both offset (zero current emittance) and slope (emittance change with current). The slope error indicates measurement error and/or additional current-dependent physics at the ATF; the offset error, that the assumed Coulomb log is correct to within a factor of 1.75.Comment: 17 pages, 6 figures, .bbl fil

    A SNP assay for assessing diversity in immune genes in the honey bee (Apis mellifera L.)

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    With a growing number of parasites and pathogens experiencing large-scale range expansions, monitoring diversity in immune genes of host populations has never been so important because it can inform on the adaptive potential to resist the invaders. Population surveys of immune genes are becoming common in many organisms, yet they are missing in the honey bee (Apis mellifera L.), a key managed pollinator species that has been severely affected by biological invasions. To fill the gap, here we identified single nucleotide polymorphisms (SNPs) in a wide range of honey bee immune genes and developed a medium-density assay targeting a subset of these genes. Using a discovery panel of 123 whole-genomes, representing seven A. mellifera subspecies and three evolutionary lineages, 180 immune genes were scanned for SNPs in exons, introns (< 4 bp from exons), 3’ and 5ÂŽUTR, and < 1 kb upstream of the transcription start site. After application of multiple filtering criteria and validation, the final medium-density assay combines 91 quality-proved functional SNPs marking 89 innate immune genes and these can be readily typed using the high-sample-throughput iPLEX MassARRAY system. This medium-density-SNP assay was applied to 156 samples from four countries and the admixture analysis clustered the samples according to their lineage and subspecies, suggesting that honey bee ancestry can be delineated from functional variation. In addition to allowing analysis of immunogenetic variation, this newly-developed SNP assay can be used for inferring genetic structure and admixture in the honey bee.We are deeply indebted to Frank Aguiar, LuĂ­s Silva, Edgardo Melo, JoĂŁo Martins, JoĂŁo Melo, Manuel Moura, Manuel Viveiros, and Ricardo Sousa from "Direção Regional da Agricultura e Desenvolvimento Rural dos Açores" (Portugal), and to Laura Garreau, Laurent Maugis, Pascale Sauvage and Jacques Kermagoret, from “Association Conservatoire de l’Abeille Noir Bretonne” (France), for sampling the apiaries in SĂŁo Miguel, Santa Maria, and Ouessant islands. Genotyping was outsourced to the Epigenetics and Genotyping laboratory, Central Unit for Research in Medicine (UCIM), University of Valencia, Spain. Data analyses were performed using computational resources at the Research Centre in Digitalization and Intelligent Robotics (CeDRI), Instituto PolitĂ©cnico de Bragança. Ana Rita Lopes is supported by a PhD scholarship (SFRH/BD/143627/2019) from the Foundation for Science and Technology (FCT), Portugal. FCT provided financial support by national funds (FCT/MCTES) to CIMO (UIDB/00690/2020).This research was funded through the projects BEEHAPPY (POCI-01-0145- FEDER-029871, FCT and COMPETE/QREN/EU) and BEEHEAL. BEEHEAL was funded by the ARIMNet2 2016 Call by the following agencies: INIA (Spain), MOARD (Israel), ANR (France) and FCT (Portugal). ARIMNet2 (ERA-NET) received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no. 618127.info:eu-repo/semantics/publishedVersio

    AMPK is a mechano-metabolic sensor linking cell adhesion and mitochondrial dynamics to Myosin-dependent cell migration

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    Cell migration is crucial for cancer dissemination. We find that AMP-activated protein kinase (AMPK) controls cell migration by acting as an adhesion sensing molecular hub. In 3-dimensional matrices, fast-migrating amoeboid cancer cells exert low adhesion/low traction linked to low ATP/AMP, leading to AMPK activation. In turn, AMPK plays a dual role controlling mitochondrial dynamics and cytoskeletal remodelling. High AMPK activity in low adhering migratory cells, induces mitochondrial fission, resulting in lower oxidative phosphorylation and lower mitochondrial ATP. Concurrently, AMPK inactivates Myosin Phosphatase, increasing Myosin II-dependent amoeboid migration. Reducing adhesion or mitochondrial fusion or activating AMPK induces efficient rounded-amoeboid migration. AMPK inhibition suppresses metastatic potential of amoeboid cancer cells in vivo, while a mitochondrial/AMPK-driven switch is observed in regions of human tumours where amoeboid cells are disseminating. We unveil how mitochondrial dynamics control cell migration and suggest that AMPK is a mechano-metabolic sensor linking energetics and the cytoskeleton. Cell metabolism must adapt to the energy needs of migrating cells. This study finds that fast amoeboid migrating cells harbor high AMPK activity, which controls both mitochondrial dynamics and cytoskeletal remodeling, enabling reduced energy needs

    AMPK is a mechano-metabolic sensor linking cell adhesion and mitochondrial dynamics to Myosin-dependent cell migration

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    Cell migration is crucial for cancer dissemination. We find that AMP-activated protein kinase (AMPK) controls cell migration by acting as an adhesion sensing molecular hub. In 3-dimensional matrices, fast-migrating amoeboid cancer cells exert low adhesion/low traction linked to low ATP/AMP, leading to AMPK activation. In turn, AMPK plays a dual role controlling mitochondrial dynamics and cytoskeletal remodelling. High AMPK activity in low adhering migratory cells, induces mitochondrial fission, resulting in lower oxidative phosphorylation and lower mitochondrial ATP. Concurrently, AMPK inactivates Myosin Phosphatase, increasing Myosin II-dependent amoeboid migration. Reducing adhesion or mitochondrial fusion or activating AMPK induces efficient rounded-amoeboid migration. AMPK inhibition suppresses metastatic potential of amoeboid cancer cells in vivo, while a mitochondrial/AMPK-driven switch is observed in regions of human tumours where amoeboid cells are disseminating. We unveil how mitochondrial dynamics control cell migration and suggest that AMPK is a mechano-metabolic sensor linking energetics and the cytoskeleton

    Projeto BEEHEAL: promover a saĂșde da abelha para uma agricultura sustentĂĄvel

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    O BEEHEAL, com o tĂ­tulo original “Promoting bee health for sustainable agriculture”, Ă© um projeto internacional colaborativo aprovado no Ăąmbito da Ação ERA-Net ARIMNet2 (Coordination of Agricultural Research in the Mediterranean). O projeto Ă© coordenado por Raquel MartĂ­n- HernĂĄndez, investigadora do “Centro de InvestigaciĂłn ApĂ­cola y Agroambiental de Marchamalo” (CAR), Espanha. Para alĂ©m deste centro de investigação, representado por Raquel MartĂ­n-HernĂĄndez e Mariano Higes, o consĂłrcio inclui mais trĂȘs instituiçÔes, nomeadamente: o Centro de Investigação de Montanha (CIMO) do Instituto PolitĂ©cnico de Bragança, representado por M. Alice Pinto e Ana Rita Lopes, o “Centre de Recherche Provence-Alpes-CĂŽte d’Azur UnitĂ©: Abeilles et Environnement do “Institut National de la Recherche Agronomique” (INRA), França, representado por Yves Le conte, Anne Dalmon e Maritza Maritza Reyes-Carreno, e o “Volcani Center” da “Agricultural Research Organization” (ARO), Israel, representado por Nor Chevjanovsky e Victoria Soroker. As populaçÔes de abelha melĂ­fera (Apis mellifera L.) tĂȘm vindo a sofrer perdas acentuadas em todo o mundo. Estas perdas estĂŁo relacionado com vĂĄrios factores, que podem atuar sozinhos ou em combinação, incluindo (i) propagação de parasitas e agentes patogĂ©nicos exĂłticos , como por exemplo o ĂĄcaro ectoparasita Varroa destructor, o qual serve de vetor de transmissĂŁo de vĂĄrios vĂ­rus, e o fungo microsporĂ­deo Nosema ceranae, (ii) exposição das colĂłnias a agro-quĂ­micos, (iii) mĂĄ nutrição, (iv) alteraçÔes climĂĄticas, entre outros (vanEngelsdorp & Meixner, 2010; Potts et al., 2010).Ao Paulo Ventura pelo acompanhamento tĂ©cnico feito ao apĂĄrio no primeiro ano do projeto. O BEEHEAL Ă© financiado por ARIMNet2 (2016) com os financiadores nacionais Instituto Nacional de InvestigaciĂłn y Teccnologia Agraria y alimentaria (INIA – Espanha), Agence Nationale de la recherche (ARN – France), Ministry off Agriculture & Rural Development, (MOARD – Israel) e Fundação para a CiĂȘncia e a Tecnologia (FCT – Portugal)info:eu-repo/semantics/publishedVersio

    Swift follow-up observations of candidate gravitational-wave transient events

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    We present the first multi-wavelength follow-up observations of two candidate gravitational-wave (GW) transient events recorded by LIGO and Virgo in their 2009-2010 science run. The events were selected with low latency by the network of GW detectors and their candidate sky locations were observed by the Swift observatory. Image transient detection was used to analyze the collected electromagnetic data, which were found to be consistent with background. Off-line analysis of the GW data alone has also established that the selected GW events show no evidence of an astrophysical origin; one of them is consistent with background and the other one was a test, part of a "blind injection challenge". With this work we demonstrate the feasibility of rapid follow-ups of GW transients and establish the sensitivity improvement joint electromagnetic and GW observations could bring. This is a first step toward an electromagnetic follow-up program in the regime of routine detections with the advanced GW instruments expected within this decade. In that regime multi-wavelength observations will play a significant role in completing the astrophysical identification of GW sources. We present the methods and results from this first combined analysis and discuss its implications in terms of sensitivity for the present and future instruments.Comment: Submitted for publication 2012 May 25, accepted 2012 October 25, published 2012 November 21, in ApJS, 203, 28 ( http://stacks.iop.org/0067-0049/203/28 ); 14 pages, 3 figures, 6 tables; LIGO-P1100038; Science summary at http://www.ligo.org/science/Publication-S6LVSwift/index.php ; Public access area to figures, tables at https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p110003
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