28 research outputs found

    Enhanced Astrocytic Ca\u3csup\u3e2+\u3c/sup\u3e Signals Contribute to Neuronal Excitotoxicity after Status Epilepticus

    Get PDF
    Status epilepticus (SE), an unremitting seizure, is known to cause a variety of traumatic responses including delayed neuronal death and later cognitive decline. Although excitotoxicity has been implicated in this delayed process, the cellular mechanisms are unclear. Because our previous brain slice studies have shown that chemically induced epileptiform activity can lead to elevated astrocytic Ca2+ signaling and because these signals are able to induce the release of the excitotoxic transmitter glutamate from these glia, we asked whether astrocytes are activated during status epilepticus and whether they contribute to delayed neuronal death in vivo. Using two-photon microscopy in vivo, we show that status epilepticus enhances astrocytic Ca2+ signals for 3 d and that the period of elevated glial Ca2+ signaling is correlated with the period of delayed neuronal death. To ask whether astrocytes contribute to delayed neuronal death, we first administered antagonists which inhibit gliotransmission: MPEP [2-methyl-6-(phenylethynyl)pyridine], a metabotropic glutamate receptor 5 antagonist that blocks astrocytic Ca2+ signals in vivo, and ifenprodil, an NMDA receptor antagonist that reduces the actions of glial-derived glutamate. Administration of these antagonists after SE provided significant neuronal protection raising the potential for a glial contribution to neuronal death. To test this glial hypothesis directly, we loaded Ca2+ chelators selectively into astrocytes after status epilepticus.We demonstrate that the selective attenuation of glial Ca2+ signals leads to neuronal protection. These observations support neurotoxic roles for astrocytic gliotransmission in pathological conditions and identify this process as a novel therapeutic target

    NT2 Derived Neuronal and Astrocytic Network Signalling

    Get PDF
    A major focus of stem cell research is the generation of neurons that may then be implanted to treat neurodegenerative diseases. However, a picture is emerging where astrocytes are partners to neurons in sustaining and modulating brain function. We therefore investigated the functional properties of NT2 derived astrocytes and neurons using electrophysiological and calcium imaging approaches. NT2 neurons (NT2Ns) expressed sodium dependent action potentials, as well as responses to depolarisation and the neurotransmitter glutamate. NT2Ns exhibited spontaneous and coordinated calcium elevations in clusters and in extended processes, indicating local and long distance signalling. Tetrodotoxin sensitive network activity could also be evoked by electrical stimulation. Similarly, NT2 astrocytes (NT2As) exhibited morphology and functional properties consistent with this glial cell type. NT2As responded to neuronal activity and to exogenously applied neurotransmitters with calcium elevations, and in contrast to neurons, also exhibited spontaneous rhythmic calcium oscillations. NT2As also generated propagating calcium waves that were gap junction and purinergic signalling dependent. Our results show that NT2 derived astrocytes exhibit appropriate functionality and that NT2N networks interact with NT2A networks in co-culture. These findings underline the utility of such cultures to investigate human brain cell type signalling under controlled conditions. Furthermore, since stem cell derived neuron function and survival is of great importance therapeutically, our findings suggest that the presence of complementary astrocytes may be valuable in supporting stem cell derived neuronal networks. Indeed, this also supports the intriguing possibility of selective therapeutic replacement of astrocytes in diseases where these cells are either lost or lose functionality

    Mimicking human neuronal pathways in silico: an emergent model on the effective connectivity

    Get PDF
    International audienceWe present a novel computational model that detects temporal configurations of a given human neuronal pathway and constructs its artificial replication. This poses a great challenge since direct recordings from individual neurons are impossible in the human central nervous system and therefore the underlying neuronal pathway has to be considered as a black box. For tackling this challenge, we used a branch of complex systems modeling called artificial self-organization in which large sets of software entities interacting locally give rise to bottom-up collective behaviors. The result is an emergent model where each software entity represents an integrate-and-fire neuron. We then applied the model to the reflex responses of single motor units obtained from conscious human subjects. Experimental results show that the model recovers functionality of real human neuronal pathways by comparing it to appropriate surrogate data. What makes the model promising is the fact that, to the best of our knowledge, it is the first realistic model to self-wire an artificial neuronal network by efficiently combining neuroscience with artificial self-organization. Although there is no evidence yet of the model's connectivity mapping onto the human connectivity, we anticipate this model will help neuroscientists to learn much more about human neuronal networks, and could also be used for predicting hypotheses to lead future experiments

    Fungal Planet description sheets: 1284-1382

    Get PDF
    Novel species of fungi described in this study include those from various countries as follows: Antartica, Cladosporium austrolitorale from coastal sea sand. Australia, Austroboletus yourkae on soil, Crepidotus innuopurpureus on dead wood, Curvularia stenotaphri from roots and leaves of Stenotaphrum secundatum and Thecaphora stajsicii from capsules of Oxalis radicosa. Belgium, Paraxerochrysium coryli (incl. Paraxerochrysium gen. nov.) from Corylus avellana. Brazil, Calvatia nordestina on soil, Didymella tabebuiicola from leaf spots on Tabebuia aurea, Fusarium subflagellisporum from hypertrophied floral and vegetative branches of Mangifera indica and Microdochium maculosum from living leaves of Digitaria insularis. Canada, Cuphophyllus bondii fromagrassland. Croatia, Mollisia inferiseptata from a rotten Laurus nobilis trunk. Cyprus, Amanita exilis oncalcareoussoil. Czech Republic, Cytospora hippophaicola from wood of symptomatic Vaccinium corymbosum. Denmark, Lasiosphaeria deviata on pieces of wood and herbaceousdebris. Dominican Republic, Calocybella goethei among grass on a lawn. France (Corsica) , Inocybe corsica onwetground. France (French Guiana) , Trechispora patawaensis on decayed branch of unknown angiosperm tree and Trechispora subregularis on decayed log of unknown angiosperm tree. [...]P.R. Johnston thanks J. Sullivan (Lincoln University) for the habitat image of Kowai Bush, Duckchul Park (Manaaki Whenua – Landcare Research) for the DNA sequencing, and the New Zealand Department of Conservation for permission to collect the specimens; this research was supported through the Manaaki Whenua – Landcare Research Biota Portfolio with funding from the Science and Innovation Group of the New Zealand Ministry of Business, Innovation and Employment. V. Hubka was supported by the Czech Ministry of Health (grant number NU21-05-00681), and is grateful for the support from the Japan Society for the Promotion of Science – grant-in-aid for JSPS research fellow (grant no. 20F20772). K. Glässnerová was supported by the Charles University Grant Agency (grant No. GAUK 140520). J. Trovão and colleagues were financed by FEDERFundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 – Operational Programme for Competitiveness and Internationalisation (POCI), and by Portuguese funds through FCT – Fundação para a Ciência e a Tecnologia in the framework of the project POCI-01-0145-FEDER-PTDC/ EPH-PAT/3345/2014. This work was carried out at the R&D Unit Centre for Functional Ecology – Science for People and the Planet (CFE), with reference UIDB/04004/2020, financed by FCT/MCTES through national funds (PIDDAC). J. Trovão was also supported by POCH – Programa Operacional Capital Humano (co-funding by the European Social Fund and national funding by MCTES), through a ‘FCT – Fundação para a Ciência e Tecnologia’ PhD research grant (SFRH/BD/132523/2017). D. Haelewaters acknowledges support from the Research Foundation – Flanders (Junior Postdoctoral Fellowship 1206620N). M. Loizides and colleagues are grateful to Y. Cherniavsky for contributing collections AB A12-058-1 and AB A12- 058-2, and Á. Kovács and B. Kiss for their help with molecular studies of these specimens. C. Zmuda is thanked for assisting with the collection of ladybird specimens infected with Hesperomyces parexochomi. A.V. Kachalkin and colleagues were supported by the Russian Science Foundation (grant No. 19-74-10002). The study of A.M. Glushakova was carried out as part of the Scientific Project of the State Order of the Government of Russian Federation to Lomonosov Moscow State University No. 121040800174-6. S. Nanu acknowledges the Kerala State Council for Science, Technology and Environment (KSCSTE) for granting a research fellowship and is grateful to the Chief Conservator of Forests and Wildlife for giving permission to collect fungal samples. A. Bañares and colleagues thank L. Monje and A. Pueblas of the Department of Drawing and Scientific Photography at the University of Alcalá for their help in the digital preparation of the photographs, and J. Rejos, curator of the AH herbarium for his assistance with the specimens examined in the present study. The research of V. Antonín received institutional support for long-term conceptual development of research institutions provided by the Ministry of Culture (Moravian Museum, ref. MK000094862). The studies of E.F. Malysheva, V.F. Malysheva, O.V. Morozova, and S.V. Volobuev were carried out within the framework of a research project of the Komarov Botanical Institute RAS, St Petersburg, Russia (АААА-А18-118022090078-2) using equipment of its Core Facility Centre ‘Cell and Molecular Technologies in Plant Science’.The study of A.V. Alexandrova was carried out as part of the Scientific Project of the State Order of the Government of Russian Federation to Lomonosov Moscow State University No. 121032300081-7. The Kits van Waveren Foundation (Rijksherbariumfonds Dr E. Kits van Waveren, Leiden, Netherlands) contributed substantially to the costs of sequencing and travelling expenses for M.E. Noordeloos. The work of B. Dima was partly supported by the ÚNKP- 20-4 New National Excellence Program of the Ministry for Innovation and Technology from the source of the National Research, Development and Innovation Fund. The work of L. Nagy was supported by the ‘Momentum’ program of the Hungarian Academy of Sciences (contract No. LP2019- 13/2019 to L.G.N.). G.A. Kochkina and colleagues acknowledge N. Demidov for the background photograph, and N. Suzina for the SEM photomicrograph. The research of C.M. Visagie and W.J. Nel was supported by the National Research Foundation grant no 118924 and SFH170610239162. C. Gil-Durán acknowledges Agencia Nacional de Investigación y Desarrollo, Ministerio de Ciencia, Tecnología, Conocimiento e Innovación, Gobierno de Chile, for grant ANID – Fondecyt de Postdoctorado 2021 – N° 3210135. R. Chávez and G. Levicán thank DICYT-USACH and acknowledges the grants INACH RG_03-14 and INACH RT_31-16 from the Chilean Antarctic Institute, respectively. S. Tiwari and A. Baghela would like to acknowledge R. Avchar and K. Balasubramanian from the Agharkar Research Institute, Pune, Maharashtra for helping with the termite collection. S. Tiwari is also thankful to the University Grants Commission, Delhi (India) for a junior research fellowship (827/(CSIR-UGC NET DEC.2017)). R. Lebeuf and I. Saar thank D. and H. Spencer for collecting and photographing the holotype of C. bondii, and R. Smith for photographing the habitat. A. Voitk is thanked for helping with the colour plate and review of the manuscript, and the Foray Newfoundland and Labrador for providing the paratype material. I. Saar was supported by the Estonian Research Council (grant PRG1170) and the European Regional Development Fund (Centre of Excellence EcolChange). M.P.S. Câmara acknowledges the ‘Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq’ for the research productivity fellowship, and financial support (Universal number 408724/2018-8). W.A.S. Vieira acknowledges the ‘Coordenação de Aperfeiçoamento Pessoal de Ensino Superior – CAPES’ and the ‘Programa Nacional de Pós-Doutorado/CAPES – PNPD/CAPES’ for the postdoctoral fellowship. A.G.G. Amaral acknowledges CNPq, and A.F. Lima and I.G. Duarte acknowledge CAPES for the doctorate fellowships. F. Esteve-Raventós and colleagues were financially supported by FEDER/ Ministerio de Ciencia, Innovación y Universidades – Agencia Estatal de Investigación (Spain)/ Project CGL2017-86540-P. The authors would like to thank L. Hugot and N. Suberbielle (Conservatoire Botanique National de Corse, Office de l’Environnement de la Corse, Corti) for their help. The research of E. Larsson is supported by The Swedish Taxonomy Initiative, SLU Artdatabanken, Uppsala. Financial support was provided to R.J. Ferreira by the National Council for Scientific and Technological Development (CNPq), and to I.G. Baseia, P.S.M. Lúcio and M.P. Martín by the National Council for Scientific and Technological Development (CNPq) under CNPq-Universal 2016 (409960/2016-0) and CNPq-visiting researcher (407474/2013-7). J. Cabero and colleagues wish to acknowledge A. Rodríguez for his help to describe Genea zamorana, as well as H. Hernández for sharing information about the vegetation of the type locality. S. McMullan-Fisher and colleagues acknowledge K. Syme (assistance with illustrations), J. Kellermann (translations), M. Barrett (collection, images and sequences), T. Lohmeyer (collection and images) and N. Karunajeewa (for prompt accessioning). This research was supported through funding from Australian Biological Resources Study grant (TTC217-06) to the Royal Botanic Gardens Victoria. The research of M. Spetik and co-authors was supported by project No. CZ.02.1.01/0.0/0.0 /16_017/0002334. N. Wangsawat and colleagues were partially supported by NRCT and the Royal Golden Jubilee Ph.D. programme, grant number PHD/0218/2559. They are thankful to M. Kamsook for the photograph of the Phu Khiao Wildlife Sanctuary and P. Thamvithayakorn for phylogenetic illustrations. The study by N.T. Tran and colleagues was funded by Hort Innovation (Grant TU19000). They also thank the turf growers who supported their surveys and specimen collection. N. Matočec, I. Kušan, A. Pošta, Z. Tkalčec and A. Mešić thank the Croatian Science Foundation for their financial support under the project grant HRZZ-IP-2018-01-1736 (ForFungiDNA). A. Pošta thanks the Croatian Science Foundation for their support under the grant HRZZ-2018-09-7081. A. Morte is grateful to Fundación Séneca – Agencia de Ciencia y Tecnología de la Región de Murcia (20866/ PI/18) for financial support. The research of G. Akhmetova, G.M. Kovács, B. Dima and D.G. Knapp was supported by the National Research, Development and Innovation Office, Hungary (NKFIH KH-130401 and K-139026), the ELTE Thematic Excellence Program 2020 supported by the National Research, Development and Innovation Office (TKP2020-IKA-05) and the Stipendium Hungaricum Programme. The support of the János Bolyai Research Scholarship of the Hungarian Academy of Sciences and the Bolyai+ New National Excellence Program of the Ministry for Innovation and Technology to D.G. Knapp is highly appreciated. F.E. Guard and colleagues are grateful to the traditional owners, the Jirrbal and Warungu people, as well as L. and P. Hales, Reserve Managers, of the Yourka Bush Heritage Reserve. Their generosity, guidance, and the opportunity to explore the Bush Heritage Reserve on the Einasleigh Uplands in far north Queensland is greatly appreciated. The National Science Foundation (USA) provided funds (DBI#1828479) to the New York Botanical Garden for a scanning electron microscope used for imaging the spores. V. Papp was supported by the ÚNKP-21-5 New National Excellence Program of the Ministry for Innovation and Technology from the National Research, Development and Innovation Fund of Hungary. A.N. Miller thanks the WM Keck Center at the University of Illinois Urbana – Champaign for sequencing Lasiosphaeria deviata. J. Pawłowska acknowledges support form National Science Centre, Poland (grant Opus 13 no 2017/25/B/NZ8/00473). The research of T.S. Bulgakov was carried out as part of the State Research Task of the Subtropical Scientific Centre of the Russian Academy of Sciences (Theme No. 0492-2021- 0007). K. Bensch (Westerdijk Fungal Biodiversity Institute, Utrecht) is thanked for correcting the spelling of various Latin epithets.Peer reviewe

    Modelling human choices: MADeM and decision‑making

    Get PDF
    Research supported by FAPESP 2015/50122-0 and DFG-GRTK 1740/2. RP and AR are also part of the Research, Innovation and Dissemination Center for Neuromathematics FAPESP grant (2013/07699-0). RP is supported by a FAPESP scholarship (2013/25667-8). ACR is partially supported by a CNPq fellowship (grant 306251/2014-0)

    Weevils attracted to thinned lodgepole pine stands in Montana /

    No full text
    no.13
    corecore