bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamin is primed at endocytic sites for ultrafast endocytosis
Authors: Imoto Yuuta , Raychaudhuri Sumana , Fenske Pascal , Sandoval Eduardo , Itoh Kie , Blumrich Eva-Maria , Mamer Lauren , Zarebidaki Fereshteh , Söhl-Kielczynski Berit , Trimbuch Thorsten , Nayak Shraddha , Iwasa Janet H. , Jorgensen Erik M. , Cousin Michael A. , Rosenmund Christian , Watanabe Shigeki 
Published: February 2021

SummaryDynamin mediates fission of vesicles from the plasma membrane during endocytosis. Typically, dynamin is recruited from the cytosol to endocytic sites, requiring seconds to tens of seconds. However, ultrafast endocytosis in neurons internalizes vesicles as quickly as 50 ms during synaptic vesicle recycling. Here we demonstrate that Dynamin 1 is pre-recruited to endocytic sites for ultrafast endocytosis. Specifically, Dynamin 1xA, a splice variant of Dynamin 1, interacts with Syndapin 1 to form molecular condensates on the plasma membrane when the proline-rich domain of this variant is dephosphorylated. When this domain is mutated to include phosphomimetic residues or Syndapin 1’s dynamin-interacting domain is mutated, Dynamin 1xA becomes diffuse, and consequently, ultrafast endocytosis slows down by ∼100-fold. Mechanistically, Syndapin 1 acts as an adaptor by binding the plasma membrane and stores Dynamin 1xA at endocytic sites. This cache bypasses the recruitment step and accelerates endocytosis at synapses.
Impacts of COVID-19 on long-term health and health care use
Authors: Skyrud Katrine , Hernæs Kjersti Helene , Telle Kjetil , Magnusson Karin 
Published: February 2021

AimTo explore the temporal impact of mild COVID-19 on need for primary and specialist health care services.MethodsIn all persons tested for SARS-CoV-2 in Norway March 1st 2020 to February 1st 2021 (N=1 401 922), we contrasted the monthly all-cause health care use before and up to 6 months after the test (% relative difference), for patients with a positive test for SARS-CoV-2 (non-hospitalization, i.e. mild COVID-19) and patients with a negative test (no COVID-19).ResultsWe found a substantial short-term elevation in primary care use in all age groups, with men generally having a higher relative increase (men 20-44 years: 522%, 95%CI=509-535, 45-69 years: 439%, 95%CI=426-452, ≥ 70 years: 199%, 95%CI=180-218) than women (20-44 years: 342, 95%CI=334-350, 45-69 years=375, 95%CI=365-385, ≥ 70 years: 156%, 95%CI=141-171) at 1 month following positive test. At 2 months, this sex difference was less pronounced, with a (20-44 years: 21%, 95%CI=13-29, 45-69 years=38%, 95%CI=30-46, ≥ 70 years: 15%, 95%CI=3-28) increase in primary care use for men, and a (20-44 years: 30%, 95%CI=24-36, 45-69 years=57%, 95%CI=50-64, ≥ 70 years: 14%, 95%CI=4-24) increase for women. At 3 months after test, only women aged 45-70 years still had an increased primary care use (14%, 95%CI=7-20). The increase was due to respiratory- and general/unspecified conditions. We observed no long-term (4-6 months) elevation in primary care use, and no elevation in specialist care use.ConclusionMild COVID-19 gives an elevated need for primary care that vanishes 2-3 months after positive test. Middle-aged women had the most prolonged increased primary care use.
Osmolarity-regulated swelling initiates egg activation inDrosophila
Authors: York-Andersen Anna H. , Wood Benjamin W. , Wilby Elise L. , Berry Alexander S. , Weil Timothy T. 
Published: February 2021

ABSTRACTEgg activation is a series of highly coordinated processes that prepare the mature oocyte for embryogenesis. Typically associated with fertilisation, egg activation results in many downstream outcomes, including the resumption of the meiotic cell cycle, translation of maternal mRNAs and cross-linking of the vitelline membrane. While some aspects of egg activation, such as initiation factors in mammals and environmental cues in sea animals, have been well-documented, the mechanics of egg activation in insects are less well understood. For many insects, egg activation can be triggered independently of fertilisation. InDrosophila melanogaster, egg activation occurs in the oviduct resulting in a single calcium wave propagating from the posterior pole of the oocyte.Here we use physical manipulations, genetics and live imaging to demonstrate the requirement of a volume increase for calcium entry at egg activation in matureDrosophilaoocytes. The addition of water, modified with sucrose to a specific osmolarity, is sufficient to trigger the calcium wave in the mature oocyte and the downstream events associated with egg activation. We show that the swelling process is regulated by the conserved osmoregulatory channels, aquaporins (AQPs) and DEGenerin/Epithelial Na+(DEG/ENaC) channels. Furthermore, through pharmacological and genetic disruption, we reveal a concentration-dependent requirement of Trpm channels to transport calcium, most likely from the perivitelline space, across the plasma membrane into the mature oocyte.Our data establishes osmotic pressure as the mechanism that initiates egg activation inDrosophilaand is consistent with previous work from evolutionarily distant insects, including dragonflies and mosquitos, and shows remarkable similarities to the mechanism of egg activation in some plants.
The M1 and pre-M1 segments contribute differently to ion selectivity in ASICs and ENaCs
Authors: Sheikh Zeshan P. , Wulf Matthias , Friis Søren , Althaus Mike , Lynagh Timothy , Pless Stephan A. 
Published: February 2021

AbstractThe ability to discriminate between different ionic species, termed ion selectivity, is a key feature of ion channels and forms the basis for their physiological function. Members of the degenerin/epithelial sodium channel (DEG/ENaC) superfamily of trimeric ion channels are typically sodium selective, but to a surprisingly variable degree. While acid-sensing ion channels (ASICs) are weakly sodium selective (sodium:potassium around 10:1), ENaCs show a remarkably high preference for sodium over potassium (>500:1). The most obvious explanation for this discrepancy may be expected to originate from differences in the pore-lining second transmembrane segment (M2). However, these show a relatively high degree of sequence conservation between ASICs and ENaCs and previous functional and structural studies could not unequivocally establish that differences in M2 alone can account for the disparate degrees of ion selectivity. By contrast, surprisingly little is known about the contributions of the first transmembrane segment (M1) and the preceding pre-M1 region. In this study, we use conventional and non-canonical amino acid-based mutagenesis in combination with a variety of electrophysiological approaches to show that the pre-M1 and M1 regions of mASIC1a channels are major determinants of ion selectivity. Mutational investigations of the corresponding regions in hENaC show that they contribute less to ion selectivity, despite affecting ion conductance. In conclusion, our work supports the notion that the remarkably different degrees of sodium selectivity in ASICs and ENaCs are achieved through different mechanisms. The results further highlight how M1 and pre-M1 are likely to differentially affect pore structure in these related channels.
The evolution of the cytochromec6family of photosynthetic electron transfer proteins
Authors: Slater Barnaby , Kosmützky Darius , Nisbet R. Ellen R. , Howe Christopher J. 
Published: February 2021

AbstractDuring photosynthesis, electrons are transferred between the cytochromeb6fcomplex and photosystem I. This is carried out by the protein plastocyanin in plant chloroplasts. In contrast, electron transfer can be carried out by either plastocyanin or cytochromec6in many cyanobacteria and eukaryotic algal species. There are three further cytochromec6homologues: cytochromec6Ain plants and green algae, and cytochromesc6Bandc6Cin cyanobacteria. The function of these proteins is unknown. Here, we present a comprehensive analysis of the evolutionary relationship between the members of the cytochromec6family in photosynthetic organisms. Our phylogenetic analyses show that cytochromec6Band cytochromec6Care likely to be orthologues that arose from a duplication of cytochromec6, but that there is no evidence for separate origins for cytochromec6Bandc6C. We therefore propose re-naming cytochromec6Cas cytochromec6B. We show that cytochromec6Ais likely to have arisen from cytochromec6Brather than by an independent duplication of cytochromec6, and present evidence for an independent origin of a protein with some of the features of cytochromec6Ain peridinin dinoflagellates. We conclude with a new comprehensive model of the evolution of the cytochromec6family which is an integral part of understanding the function of the enigmatic cytochromec6homologues.
Disassembly of HIV envelope glycoprotein trimer immunogens is driven by antibodies elicited via immunization
Authors: Turner Hannah L. , Andrabi Raiees , Cottrell Christopher A. , Richey Sara T. , Song Ge , Callaghan Sean , Anzanello Fabio , Moyer Tyson J. , Abraham Wuhbet , Melo Mariane , Silva Murillo , Scaringi Nicole , Rakasz Eva G. , Sattentau Quentin , Irvine Darrell J. , Burton Dennis R. , Ward Andrew B. 
Published: February 2021

AbstractRationally designed protein subunit vaccines are being developed for a variety of viruses including influenza, RSV, SARS-CoV-2 and HIV. These vaccines are based on stabilized versions of the primary targets of neutralizing antibodies on the viral surface, namely viral fusion glycoproteins. While these immunogens display the epitopes of potent neutralizing antibodies, they also present epitopes recognized by non or weakly neutralizing (“off-target”) antibodies. Using our recently developed electron microscopy epitope mapping approach, we have uncovered a phenomenon wherein off-target antibodies elicited by HIV trimer subunit vaccines cause the otherwise highly stabilized trimeric proteins to degrade into cognate protomers. Further, we show that these protomers expose an expanded suite of off-target epitopes, normally occluded inside the prefusion conformation of trimer, that subsequently elicit further off-target antibody responses. Our study provides critical insights for further improvement of HIV subunit trimer vaccines for future rounds of the iterative vaccine design process.
Effectiveness of Joint Species Distribution Models in the Presence of Imperfect Detection
Authors: Hogg Stephanie , Wang Yan , Stone Lewi 
Published: February 2021

AbstractJoint species distribution models (JSDMs) are a recent development in biogeography and enable the spatial modelling of multiple species and their interactions and dependencies. However, most models do not consider imperfect detection, which can significantly bias estimates. This is one of the first papers to account for imperfect detection when fitting data with JSDMs and to explore the complications that may arise.A multivariate probit JSDM that explicitly accounts for imperfect detection is proposed, and implemented using a Bayesian hierarchical approach. We investigate the performance of the JSDM in the presence of imperfect detection for a range of factors, including varied levels of detection and species occupancy, and varied numbers of survey sites and replications. To understand how effective this JSDM is in practice, we also compare results to those from a JSDM that does not explicitly model detection but instead makes use of “collapsed data”. A case study of owls and gliders in Victoria Australia is also illustrated.Using simulations, we found that the JSDMs explicitly accounting for detection can accurately estimate intrinsic correlation between species with enough survey sites and replications. Reducing the number of survey sites decreases the precision of estimates, while reducing the number of survey replications can lead to biased estimates. For low probabilities of detection, the model may require a large number of survey replications to remove bias from estimates. However, JSDMs not explicitly accounting for detection may have a limited ability to dis-entangle detection from occupancy, which substantially reduces their ability to accurately infer the species distribution spatially. Our case study showed positive correlation between Sooty Owls and Greater Gliders, despite a low number of survey replications.To avoid biased estimates of inter-species correlations and species distributions, imperfect detection needs to be considered. However, for low probability of detection, the JSDMs explicitly accounting for detection is data hungry. Estimates from such models may still be subject to bias. To overcome the bias, researchers need to carefully design surveys and choose appropriate modelling approaches. The survey design should ensure sufficient survey replications for unbiased inferences on species inter-dependencies and occupancy.
Functional basis for calmodulation of the TRPV5 calcium channel
Authors: Roig Sara R , Thijssen Niky , Erp Merijn van , Fransen Jack , Hoenderop Joost G , van der Wijst Jenny 
Published: February 2021

AbstractWithin the transient receptor potential (TRP) superfamily of ion channels, TRPV5 is a highly Ca2+-selective channel important for active reabsorption of Ca2+in the kidney. Its channel activity is controlled by a negative feedback mechanism involving calmodulin (CaM) binding. Combining advanced microscopy techniques and biochemical assays, this study characterized the dynamic bilobal CaM regulation and binding stoichiometry. We demonstrate for the first time that functional (full-length) TRPV5 interacts with CaM in the absence of Ca2+, and this interaction is intensified at increasing Ca2+concentrations sensed by the CaM C-lobe that achieves channel pore blocking. Channel inactivation occurs without CaM N-lobe calcification. Moreover, we reveal a 1:2 stoichiometry of TRPV5:CaM binding by implementingsingle molecule photobleaching counting, a technique with great potential for studying TRP channel regulation. In conclusion, our study proposes a new model for CaM- dependent regulation –calmodulation– of the Ca2+-selective TRPV5 that involves apoCaM interaction and lobe-specific actions.
Understanding distribution and occupancy of Himalayan Monal in Uttarkashi district, Uttarakhand
Authors: Sharief Amira , Singh Hemant , Joshi Bheem Dutt , Mukherjee Tanoy , Chandra Kailash , Thakur Mukesh , Sharma Lalit Kumar 
Published: February 2021

AbstractThe Himalayan Monal is a conservation priority species in its entire distribution range. Its population is declining in many areas due to various anthropogenic threats. The information on species distribution and its abundance is lacking in many areas which are vital for conservation and management planning. Hence, through the present study, we have assessed the abundance and occupancy of Himalayan monal in Uttarkashi district (Uttarakhand). We used camera traps and conventional sign surveys for documenting the species during 2018-2019. We installed a total of 69 camera traps (2819 trap nights) and surveyed 54 trails (650 km) which represents entire habitat and topographic variability of the landscape. The occupancy and detection probability was modelled using the habitat variables. The top model showed that occupancy probability of Himalayan monal was positively influenced by the slope (β =27.52 ±16.25) and negatively influenced by Reserve Forest (RF) (β= −8.14 SE ± 4.99). The observed naïve occupancy of Himalayan Monal was 0.69 in the study area, which was slightly lower than the estimated occupancy. However, in the null model, the site occupancy estimated was found to be 0.82±0.08 and with detection probability 0.23±0.03. The overall abundance of monal was estimated about 171.58 ±10.2 in the study area with an average density of 0.62/ km2. The activity pattern analysis indicates that monal remains very active between 6.00 hrs −12.00 hrs and relatively less active during mid-day when humans are most active 11.30 hrs-16.30 hrs. The present study is a first attempt to estimate occupancy and abundance using camera traps as well as sign survey for the species primarily from non-Protected Area (PA). We found that Himalayan monal is abundant outside the PAs, which is a good indication for its long-term viability and also identified areas for conservation and management prioritization in Uttarkashi.
Human pluripotent stem cell-derived cardiomyocytes align under cyclic strain when guided by cardiac fibroblasts
Authors: Mostert Dylan , Groenen Bart , Klouda Leda , Passier Robert , Goumans Marie-Jose , Kurniawan Nicholas A. , Bouten Carlijn V.C 
Published: February 2021

AbstractThe human myocardium is a mechanically active tissue typified by anisotropic organization of the resident cells (cardiomyocytes (CMs) and cardiac fibroblasts (cFBs)) and the extracellular matrix (ECM). Upon ischemic injury, the anisotropic tissue is replaced by disorganized scar tissue, eventually resulting in loss of coordinated contraction. Efforts to re-establish tissue anisotropy in the injured myocardium are hampered by a lack of understanding on how CM and/or cFB structural organization is affected by the two major physical cues inherent in the myocardium: ECM organization and cyclic mechanical strain. Herein, we investigate the singular and combined effect of ECM (dis)organization and cyclic strain in a 2D humanin vitroco-culture model of the myocardial microenvironment. We show that (an)isotropic ECM protein patterning can guide the orientation of CMs and cFBs, both in mono- and co-culture. Subsequent application of uniaxial cyclic strain – mimicking the local anisotropic deformation of beating myocardium – causes no effect when applied parallel to the anisotropic ECM. However, when cultured on isotropic substrates, cFBs, but not CMs, orient away from the direction of cyclic uniaxial strain (strain avoidance). In contrast, CMs show strain avoidance via active remodeling of their sarcomeres only when co-cultured with at least 30% cFBs. Paracrine signaling or N-cadherin-mediated communication between CMs and cFBs were no contributing factors, but our findings suggest that the mechanoresponsive cFBs provide structural guidance for CM orientation and elongation. Our study therefore highlights a synergistic mechanobiological interplay between CMs and cFBs in shaping tissue organization, which is of relevance for regenerating functionally organized myocardium.
In-cell structures of a conserved supramolecular array at the mitochondria-cytoskeleton interface in mammalian sperm
Authors: Leung Miguel Ricardo , Chiozzi Riccardo Zenezini , Roelofs Marc C. , Hevler Johannes F. , Ravi Ravi Teja , Maitan Paula , Zhang Min , Henning Heiko , Bromfield Elizabeth G. , Howes Stuart C. , Gadella Bart M. , Heck Albert J.R. , Zeev-Ben-Mordehai Tzviya 
Published: February 2021

SummaryMitochondria-cytoskeleton interactions modulate cellular physiology by regulating mitochondrial transport, positioning, and immobilization. However, there is very little structural information defining mitochondria-cytoskeleton interfaces in any cell type. Here, we use cryo-focused ion beam milling-enabled cryo-electron tomography to image mammalian sperm, where mitochondria wrap around the ciliary cytoskeleton. We find that mitochondria are tethered to their neighbors through inter-mitochondrial linkers and are anchored to the cytoskeleton through ordered arrays on the outer mitochondrial membrane. We use subtomogram averaging to resolve in-cell structures of these arrays from three mammalian species, revealing they are conserved across species despite variations in mitochondrial dimensions and cristae organization. We find that the arrays consist of boat-shaped particles anchored on a network of membrane pores whose arrangement and dimensions are consistent with voltage dependent anion channels. Proteomics and in-cell cross-linking mass spectrometry suggest that the conserved arrays are composed of glycerol kinase-like proteins. Ordered supramolecular assemblies may serve to stabilize similar contact sites in other cell types where mitochondria need to be immobilized in specific subcellular environments, such as in muscles and neurons.
LC-MS Based Draft Map of theArabidopsis thalianaNuclear Proteome and Protein Import in Pattern Triggered Immunity
Authors: Ayash Mohamed , Abukhalaf Mohammad , Thieme Domenika , Proksch Carsten , Heilmann Mareike , Schattat Martin , Hoehenwarter Wolfgang 
Published: February 2021

AbstractDespite its central role as the ark of genetic information and gene expression the plant nucleus is surprisingly understudied. We isolated nuclei from theArabidopsis thalianadark grown cell culture left untreated and treated with flg22 and nlp20, two elicitors of pattern triggered immunity (PTI) in plants, respectively. An LC-MS based discovery proteomics approach was used to measure the nuclear proteome fractions. An enrichment score based on the relative abundance of cytoplasmic, mitochondrial and golgi markers in the nuclear protein fraction allowed us to curate the nuclear proteome producing high quality catalogs of around 3,000 nuclear proteins under untreated and both PTI conditions. The measurements also covered low abundant proteins including more than 100 transcription factors and transcriptional co-activators. Protein import into the nucleus in plant immunity is known. Here we sought to gain a broader impression of this phenomenon employing our proteomics data and found 157 and 73 proteins to be putatively imported into the nucleus upon stimulus with flg22 and nlp20, respectively. Furthermore, the abundance of 93 proteins changed significantly in the nucleus following elicitation of immunity. These results suggest promiscuous ribosome assembly and retrograde signaling from the mitochondrion to the nucleus including Prohibitins and Cytochrome C, in the two forms of PTI.
Screening of the antimicrobial activity of marine sponge extracts from Martinique
Authors: Piron Julie , Pastour Jessica , Tysklind Niklas , Smith-Ravin Juliette , Priam Fabienne 
Published: February 2021

AbstractMarine sponges are known for their antimicrobial, antifungal, and cytotoxic activity. In this study, the activity of aqueous and ethanoic extracts of 3 sponges from Martinique were tested on 5 bacterial strains:Bascillus cereus(CIP 783),Echerichia coli(CIP 54127),Pseudomonas aeruginosa(CIP A22),Staphylococcus aureus(CIP 67.8) andStaphylococcus saprophyticus(CIP 76125). The antimicrobial activity ofAgelas clathrodes, Desmapsamma anchorata, andVerongula rigida, was demonstrated using the disc diffusion method and by determining the minimum inhibitory concentration and the minimum bactericidal concentration. The ethanoic extract ofAgelas clathrodeshad an inhibitory activity specifically onStaphylococcus aureusandStaphylococcus saprophyticus. No activity was observed for the other extracts. Further chemical analyses will be carried out in order to identify the active molecules of these sponges.