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Biochemical and microscopical investigation of heavy metal associated isoprenylated plant protein 7 (HIPP7) as a component and regulator of plasmodesmata
No full textThe plant cell wall is a barrier to intercellular, cytoplasmic connectivity. Plasmodesmata (PD) are membrane-lined channels which form specialised gaps across the cell wall to provide and mediate cell-to-cell connectivity. This controlled connectivity allows for the sharing of resources and signals to coordinate the efforts of the various cell types. Whilst the overall structure of plasmodesmata has been described in significant detail, only recent years have seen notable progress in proteomic identification of their molecular components. Conversely, the plasmodesmata-specific functions of newly identified plasmodesmata-localised proteins remain to be characterised. The mechanisms for plasmodesmata regulation are not fully understood and do not reach the level of sophistication expected of a system so essential to plant life.
One protein family for which multiple members have been shown to be plasmodesmata-associated are Heavy Metal Associated Isoprenylated Plant Proteins (HIPPs), a group of plant-specific metal chaperones. However, there was previously no information regarding their plasmodesmata-specific functions. In this thesis, HIPP7 is introduced as a novel regulator of cell connectivity. The effect of HIPP7 expression on cell-to-cell trafficking of fluorescent tracers, virus spread, accumulation of the PD-regulating cell wall component callose, and the localisation of other known components of PD is characterised. Serial Block Face Scanning Electron Microscopy (SBF-SEM) from transverse sectioning in the root meristem was used to uncover effects on plasmodesmata density and architecture and a biotin ligase system for proximity labelling has produced a HIPP7 interactome. These varied, targeted investigations of HIPP7 have provided further insight into the regulation of plasmodesmata and summarise numerous methods for investigation of a protein otherwise largely uncharacterised as a PD component."This work was supported by a scholarship from the Eastbio Doctoral Training Partnership from the U.K. Biotechnology and Biological Sciences Research Council (BBSRC); grant number BB/T00875X/1."--Fundin
Planets observed with CHEOPS : two super-Earths orbiting the red dwarf star TOI-776
Get PDFFunding: CHEOPS is an ESA mission in partnership with Switzerland with important contributions to the payload and the ground segment from Austria, Belgium, France, Germany, Hungary, Italy, Portugal, Spain, Sweden, and the United Kingdom. The CHEOPS Consortium would like to gratefully acknowledges the support received by all the agencies, offices, universities, and industries involved. Their flexibility and willingness to explore new approaches were essential to the success of this mission. Funding for the TESS mission is provided by NASA’s Science Mission Directorate. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. This work is done under the framework of the KESPRINT collaboration (http://www.kesprint.science). KESPRINT is an international consortium devoted to the characterisation and research of exoplanets discovered with space-based missions. It is based in part on observations made with ESO Telescopes at the La Silla Observatory (Chile) under programme 106.21TJ.001 (P.I. D. Gandolfi). This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. M.F., I.Y.G., C.M.P., A.Br., and J.K. gratefully acknowledge the support of the Swedish National Space Agency (DNR 177/19, 174/18, 65/19, 2020-00104). A.J.M. gratefully acknowledges the support of the SNSA funding (Career grant 120/19C). T.G.W., A.C.C., and K.H. acknowledge support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant ST/R003203/1. Y.A. and M.J.H. acknowledge the support of the Swiss National Fund under grant 200020.172746. D.G. and L.M.S. gratefully acknowledge financial support from the CRT foundation under Grant 2018.2323 “Gaseous or rocky? Unveiling the nature of small worlds”. D.G., M.F., X.B., S.C., and J.L. acknowledge their roles as ESA-appointed CHEOPS science team members. A.De. and D.E. acknowledge support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (project Four Aces; grant agreement No 724427). A.De., A.Le., acknowledge support from the Swiss National Centre for Competence in Research “PlanetS” and the Swiss National Science Foundation (SNSF). A.H., Sz.C., M.E., and H.R. acknowledge support by DFG grants HA 3279/12-1 and RA 714/14-1 within the DFG Schwerpunkt SPP 1992, “Exploring the Diversity of Extrasolar Planets”. R.L. acknowledges funding from University of La Laguna through the Margarita Salas Fellowship from the Spanish Ministry of Universities ref. UNI/551/2021-May 26, and under the EU Next Generation funds. S.H. gratefully acknowledges CNES funding through the grant 837319. The MOC activities have been supported by the ESA contract no. 4000124370. S.C.C.B. and V.A. acknowledge support from FCT through FCT contracts nr. IF/01312/2014/CP1215/CT0004 and IF/00650/2015/CP1273/CT0001, respectively. This work was supported by FCT – Fundação para a Ciência e a Tecnologia through national funds and by FEDER through COMPETE2020 – Programa Operacional Competitividade e Internacionalização by these grants: UID/FIS/04434/2019; UIDB/04434/2020; UIDP/04434/2020; PTDC/FISAST/32113/2017, POCI-01-0145-FEDER-032113; PTDC/FIS-AST/28953/2017, POCI-01-0145-FEDER-028953; PTDC/FIS-AST/28987/2017, POCI-01-0145- FEDER-028987. S.G.S. acknowledges support from FCT through FCT contract nr. CEECIND/00826/2018 and POPH/FSE (EC). We acknowledge support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grants PID2019-107061GB-C66, ESP2016-80435-C2-1-R, ESP2016-80435-C2-2-R, PGC2018-098153-B-C33, PGC2018-098153-B-C31, ESP2017-87676-C5-1-R, MDM-2017-0737 Unidad de Excelencia Maria de Maeztu-Centro de Astrobiología (INTA-CSIC), as well as the sup- port of the Generalitat de Catalunya/CERCA programme. This project was supported by the CNES. L.D. is an F.R.S.-FNRS Postdoctoral Researcher. The Belgian participation to CHEOPS has been supported by the Belgian Federal Science Policy Office (BELSPO) in the framework of the PRODEX Program, and by the University of Liège through an ARC grant for Concerted Research Actions financed by the Wallonia-Brussels Federation. K.G.I. is the ESA CHEOPS Project Scientist and is responsible for the ESA CHEOPS Guest Observers Programme. She does not participate in, or contribute to, the definition of the Guaranteed Time Programme of the CHEOPS mission through which observations described in this paper have been taken, nor to any aspect of target selection for the programme. G.L. acknowledges support by CARIPARO Foundation, according to the agreement CARIPARO-Università degli Studi di Padova (Pratica n. 2018/0098). This work was granted access to the HPC resources of MesoPSL financed by the Région Île-de-France and the project Equip@Meso (reference ANR-10-EQPX- 29-01) of the programme Investissements d’Avenir supervised by the Agence Nationale pour la Recherche. M.L. acknowledges support from the Swiss National Science Foundation under grant number PCEFP2.194576. P.F.L.M. acknowledges support from STFC grant number ST/M001040/1. L.D.N. thanks the Swiss National Science Foundation for support under Early Postdoc. Mobility grant P2GEP2.200044. This work was also partially supported by a grant from the Simons Foundation (PI Queloz, grant number 327127). I.R. acknowledges support from the Spanish Ministry of Science and Innovation and the European Regional Development Fund through grant PGC2018-098153-B- C33, as well as the support of the Generalitat de Catalunya/CERCA programme. This project has been supported by the Hungarian National Research, Development and Innovation Office (NKFIH) grant K-125015, the MTA-ELTE Lendület Milky Way Research Group and the City of Szombathely under Agreement No. 67.177-21/2016. This research received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement n 803193/BEBOP), and from the Science and Technology Facilities Council (STFC.; grant ST/S00193X/1). V.V.G. is an F.R.S-FNRS Research Associate.Context . M-dwarf stars are the most common of potential exoplanet host stars in the Galaxy. It is therefore very important to understand planetary systems orbiting such stars and to determine the physical parameters of such planets with high precision. Also with the launch of the James Webb Space Telescope (JWST) the observation of atmospheric parameters of planets orbiting these stars has begun. It is therefore required to determine properties of potential targets. Aims . Two planets around the red dwarf TOI-776 were detected by TESS. The objective of our study was to use transit observations obtained by the CHEOPS space mission to improve the current precision of the planetary radii, as well as additional radial velocity (RV) data in order to improve mass estimates of the two planets. Using these quantities, we wanted to derive the bulk densities of those planets, improving the precision in earlier results, and use this information to put them in context of other exoplanetary systems involving very low mass stars. Methods . Utilizing new transit data from the CHEOPS satellite and its photometric telescope, we obtained very high precision planetary transit measurements. Interpretation of these provides updated planetary radii, along with other system parameters. A concurrent ESO large observing program using the high precision spectrograph HARPS has doubled the available radial velocity data. Calculating the power spectrum of a number of stellar activity indices we update the previously estimated stellar rotation period to a lower value. Results . The CHEOPS data provide precise transit depths of 909 and 1177 ppm translating into radii of Rb = 1.798-0.077+0.078 R⊕ and Rc = 2.047-0.078+0.081 R⊕, respectively. Our interpretation of the radial velocities and activity indicator time series data estimates a stellar rotation period for this early M dwarf of ~21.1 days. A further multi-dimensional Gaussian process approach confirm this new estimate. By performing a Skew-Normal (SN) fit onto the Cross Correlation Functions we extracted the RV data and the activity indicators to estimate the planetary masses, obtaining Mb = 5.0-1.6+1.6 M⊕ and Mc = 6.9-2.5+2.6 M⊕. Conclusions . We improve the precision in planetary radius for TOI-776 b and c by a factor of more than two. Our data and modelling give us parameters of both bodies consistent with mini-Neptunes, albeit with a relatively high density. The stellar activity of TOI-776 is found to have increased by a factor larger than 2 since the last set of observations.Peer reviewe
Groups can speak : a study on group speech acts
Get PDFWe naturally interpret groups as making all kinds of speech acts. However, it is not obvious under which conditions we can properly say a group performed such actions. This thesis provides a comprehensive study of group speech acts and group communicative actions, with group assertion as my main (but not only) case study. I propose to understand group speech acts as illocutions that are not just performed by groups but attributable to groups and not just to individuals. The debate so far has included all communicative acts performed by groups —causing philosophers to misclassify cases of individual speech acts as group speech acts. I propose that group speech acts, properly understood, are distinguished by the authority to speak on behalf of the group. I start by providing a classification of the group speech acts views. Until now, there has not been a panoramic picture of the debate. Then, I analyse the case of group assertion, taking input from the debate over the epistemic normativity of assertion. I argue against previous accounts of group assertion that they do not account for some cases of scientific assertion and misclassify some individual assertions. I propose the authority account of group assertion. Next, I show that my authority account extends to all group speech acts and reject the dominant view that there are two kinds of group speech acts. Additionally, I provide a functional account of protests and distinguish group protests using the authority account. Finally, I argue that group mental states inflationism and vehicle externalism follow from group speech acts inflationist accounts like the one I defended, which means that the group belief’s vehicle can be outside the group’s members. Contrary to what some philosophers claim, this shows that we cannot hold both group speech acts inflationism and group mental states deflationism."This work was supported by Mexico’s National Council of Humanities, Science and Technology (Consejo Nacional de Humanidades, Ciencia y Tecnología, CONAHCyT) under PhD scholarship CVU 519209, by a SASP (St Andrews and Stirling Graduate Programme in Philosophy) full fee waiver; and by Mexico’s Secretary of Public Education (Secretaría de Educación Pública, SEP)."--Fundin
Competing demands on adult children : how do they shape their provision of informal care?
Get PDFFunding: This work was supported by the Economic and Social Research Council (ESRC) and Scottish Graduate School of Social Science (SGSSS) under Grant Number ES/P000681/1; and by the ESRC Centre for Population Change Connecting Generations research programme, under Grant Number ES/W002116/1.Population ageing is increasing the demand for informal care, heightening the importance of adult children as potential carers to their older parents. Adult children, however, may be subject to competing demands for informal care provision when individual characteristics, such as gender and employment status, combine with household level characteristics, such as the presence of young children or vulnerable family members. Previous research often considers these competing demands as separate factors which can influence the provision of informal care, rather than in combination. Therefore, this study exploits data from Wave 13 (2021–2023) of the UK Household Longitudinal Study and applies multicategorical multilevel analysis of individual heterogeneity and discriminatory accuracy (MAIHDA) to assess the additive and interactive role of competing demands in influencing the provision of informal care. The results indicate that the provision of informal care is driven by the additive influence of the competing demands. Moreover, they also reveal the layering of certain social characteristics, which cumulate, rather than intersect, to create a social profile with a notably higher predicted probability of providing informal care.Peer reviewe
A possible misaligned orbit for the young planet AU Mic c
Get PDFFunding: ACC acknowledges support from STFC consolidated grant number ST/V000861/1, and UKSA grant number ST/X002217/1. HY, SA, BK, and OB acknowledge funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 865624, GPRV). HMC acknowledges funding from a UKRI Future Leader Fellowship, grant number MR/S035214/1. The contributions at the Mullard Space Science Laboratory by EMB have been supported by STFC through the consolidated grant ST/W001136/1. JEO was supported by a Royal Society University Research Fellowship, and JEO’s contribution received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 853022). CH acknowledges the European Union H2020-MSCA-ITN-2019 under grant agreement no. 860470 (CHAMELEON). PFLM acknowledges support from STFC research grant number ST/R000638/1. NCS acknowledges funding by the European Union (ERC, FIERCE, 101052347) NAW acknowledges UKSA grant ST/R004838/1. ML acknowledges the support from the UKRI grant (grant number: EP/X027562/1).The AU Microscopii planetary system is only 24 Myr old, and its geometry may provide clues about the early dynamical history of planetary systems. Here, we present the first measurement of the Rossiter–McLaughlin effect for the warm sub-Neptune AU Mic c, using two transits observed simultaneously with the European Southern Observatory’s (ESO’s) Very Large Telescope (VLT)/Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO), CHaracterising ExOPlanet Satellite (CHEOPS), and Next-Generation Transit Survey (NGTS). After correcting for flares and for the magnetic activity of the host star, and accounting for transit-timing variations, we find the sky-projected spin–orbit angle of planet c to be in the range λc = 67.8+31.7 −49.0 degrees (1σ). We examine the possibility that planet c is misaligned with respect to the orbit of the inner planet b (λb = −2.96+10.44 −10.30), and the equatorial plane of the host star, and discuss scenarios that could explain both this and the planet’s high density, including secular interactions with other bodies in the system or a giant impact. We note that a significantly misaligned orbit for planet c is in some degree of tension with the dynamical stability of the system, and with the fact that we see both planets in transit, though these arguments alone do not preclude such an orbit. Further observations would be highly desirable to constrain the spin–orbit angle of planet c more preciselyPeer reviewe
A model of optimal digestive strategy in infrequently-feeding snakes
Get PDFOrganisms require energy for survival, growth, and reproduction. In a system with a finite energy supply, fluctuations in resource availability can select for plasticity in the allocation of resources between competing physiological processes. Infrequently-feeding snakes, which naturally experience extended episodes of fasting, have evolved the capacity to modulate gastrointestinal (GI) performance in response to changes in digestive load. Specifically, the gut can be downregulated during fasting to reduce metabolic maintenance costs. Some energy is, however, required to upregulate the digestive system again to allow the exploitation of captured prey. Despite significant inquiry into the relationship between sit-and-wait foraging tactics and GI plasticity, quantitative examination of the optimal digestive strategy for an infrequently-feeding snake is lacking. Here, we construct an optimisation model to quantitatively predict this strategy in terms of the length of time post-feeding after which gut downregulation occurs and the minimum prey mass required to initiate gut upregulation. Contrary to long-held assertions, our simulations predict that infrequently-feeding snakes of all sizes that practice gut downregulation benefit from consuming relatively small prey. We identify gut downregulation as an adaptive strategy when prey are small and encountered infrequently, and assert it as a critical factor in determining predator vulnerability to food scarcity. When parameterising the model, we found the distribution of potential prey body sizes to be poorly characterised in the literature. Accordingly, we identify the frequency distribution of individual body sizes within a terrestrial community as a key focus of future ecological research.Peer reviewe
Tracking individual animals can reveal the mechanisms of species loss
Get PDFFunding: R.Y.O. acknowledges support from the Kuni Endowed Junior Faculty Fellowship at the Bren School of Environmental Science & Management. C.R. acknowledges funding from the Gordon and Betty Moore Foundation (GBMF9881) and the National Geographic Society (NGS-82515R-20). M.W. acknowledges funding from the Gordon and Betty Moore Foundation (GBMF10539) and from the Academy for the Protection of Zoo Animals and Wildlife.As biodiversity loss continues, targeted conservation interventions are increasingly necessary. Stemming species loss requires mechanistic understanding of the processes governing population dynamics. However, this information is unavailable for most animals because it requires data that are difficult to collect using traditional methods. Advances in animal tracking technology have generated an avalanche of high-resolution observations for a growing list of species around the globe. To date, most research using these data has focused on questions about animal behavior, with less emphasis on population processes. Here, we argue that tracking data are uniquely poised to bring powerful new insights to the urgent, global problem of halting species extinctions by revealing when, where, how, and why populations are changing.Peer reviewe
Investigating the conformational landscape of human histidine-rich glycoprotein using amide HDX-MS
Get PDFFunding: This work was supported by the British Heart Foundation (grant no.: FS/20/3/34956) and the Biotechnology and Biological Sciences Research Council (grant no.: BB/V014684). HDX-MS facility at the University of Dundee is supported by BBSRC Capital Equipment grant BB/V019635/1. GRM is supported by a Baxter Fellowship, University of Dundee.Histidine-rich glycoprotein (HRG) is a multi-domain plasma protein involved in immune modulation, angiogenesis, coagulation and fibrinolysis. Despite its broad biological relevance, structural investigations into HRG have yielded only limited information, with no experimentally resolved three-dimensional structures of the intact protein to date. In this study, we integrate hydrogen-deuterium exchange mass spectrometry (HDX-MS) with predictive insights from AlphaFold to map the conformational landscape of HRG in solution under near-native conditions. The N1/N2 domains displayed low solvent exchange overall. However, specific regions of high-solvent exchange were also apparent providing evidence for more dynamic stretches of secondary structure and the presence of flexible loops within these regions. Our findings also reveal extensive solvent accessibility and rapid exchange kinetics within the histidine-rich region, proline-rich regions and large segments of the C-terminal domain, strongly indicating intrinsic disorder across these domains. These findings support a model in which structural flexibility underlies HRG’s capacity to engage with a wide range of molecular partners. This integrative approach offers new insight into the conformational architecture of HRG and lays the groundwork for uncovering the molecular mechanisms governing its biological activity.Peer reviewe
Improved nucleoside (2'-deoxy)ribosyltransferases maximize enzyme promiscuity while maintaining catalytic efficiency
Get PDFFunding: P.T. was funded by IBioIC (IBioIC 2020-2-1) and by BBSRC Pathfinder IAA BB/X511183/1; C.M.C. was funded by the Wellcome trust (217078/Z/19/Z). C.M.C. and D.H. were funded by research grants from NuCana plc.Nucleoside analogues have been extensively used to treat viral and bacterial infections and cancer for more than 60 years. However, their chemical synthesis is complex and often requires multiple steps and a dedicated synthetic route for every new nucleoside to be produced. Wild type nucleoside 2′-deoxyribosyltransferase enzymes are promising for biocatalysis. Guided by the structure of the enzyme from the thermophilic organism Chroococcidiopsis thermalis PCC 7203 (CtNDT) bound to the ribonucleoside analogue Immucillin-H, we designed mutants of CtNDT and the psychrotolerant Bacillus psychrosaccharolyticus (BpNDT) to improve catalytic efficiency with 3′-deoxynucleosides and ribonucleosides, while maintaining nucleobase promiscuity to generate over 100 distinct nucleoside products. Enhanced catalytic efficiency toward ribonucleosides and 3′-deoxyribonucleosides occurred via gains in turnover rate, rather than improved substrate binding. We determined the crystal structures of two engineered variants as well as kinetic parameters with different substrates, unveiling molecular details underlying their expanded substrate scope. Our rational approach generated robust enzymes and a roadmap for reaction conditions applicable to a wide variety of substrates.Peer reviewe
Editorial : novel media / media novel
Get PDFThis special issue of C21 Literature examines how the contemporary novel responds to the increasingly entangled relationship between digital media and literary writing. The editors, Sandro Eich and Dong Xia, introduce the two book review essays and five articles and contextualise how three main concerns—communications, remediations, and genres—are what transpire from the contributions. How the contemporary novel stages these aspects of everyday life under digital conditions is a shared concern across the articles, highlighting the heterogeneous forms and functions of the relationship between digital media and the novel.Peer reviewe
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