bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antibiotic resistance profile of E. coli isolates in 17 municipal wastewater utilities across Oregon
Authors: Khorshidi-Zadeh Marjan , Yiu Sue Yee , Nguyen Jacquelynn N. , Garza Gabriela L. , Waite-Cusic Joy , Radniecki Tyler S. , Navab-Daneshmand Tala 
Published: November 2021

AbstractWastewater treatment utilities are considered one of the main sources and reservoirs of antimicrobial resistance. The objective of this study was to determine the diversity and prevalence of antibiotic-resistant Escherichia coli in wastewater treatment systems across the state of Oregon. Influent, secondary effluent, final effluent, and biosolids were collected from 17 wastewater treatment utilities across Oregon during the winter and summer seasons of 2019 and 2020 (n = 246). E. coli strains were recovered from samples by culturing on mTEC, followed by confirmation with MacConkey with MUG agar plates. Antibiotic susceptibility of 1143 E. coli isolates against 8 antibiotics were determined, and resistance profiles and indices were analyzed between utilities, seasons, and flows. Antibiotic resistance phenotypes were detected in 31.6% of the collected E. coli isolates. Among those antibiotic-resistant E. coli isolates, multi-drug resistance (i.e., resistance to three or more classes of antibiotics) was harbored by 27.7% with some strains showing resistance to up to six classes of antibiotics. The most prevalent resistance was to ampicillin (n = 207) and the most common combinations of multi-drug resistance included simultaneous resistances to ampicillin, streptomycin, and tetracycline (n = 49), followed by ampicillin, streptomycin, and sulfamethoxazole/trimethoprim (n = 46). Significant correlations were observed between resistance to sulfamethoxazole/trimethoprim and resistances to ampicillin, ciprofloxacin, and tetracycline (p < 0.001). A small percentage (1.1%) of the E. coli isolates displayed extended-spectrum beta lactamase (ESBL) activity and a single isolate carried resistance to imipenem. Compared to wastewater influent, ciprofloxacin resistance was significantly more prevalent in biosolids (p <0.05) and tetracycline resistance was significantly lower in effluent (p <0.05). Seasonal impact on antibiotic-resistant E. coli in wastewater influent was observed through significantly higher multiple antibiotic resistance (MAR) index, ampicillin resistance prevalence, and ciprofloxacin resistance prevalence in summer compared to winter (p < 0.05). This state-wide study confirms the widespread distribution of antibiotic-resistant, multi-drug resistant, and extended-spectrum beta lactamase-producing E. coli in wastewater systems across different flows and seasonal variations, making them the recipients, reservoirs, and sources of antimicrobial resistance.
Genome editing in the unicellular holozoan Capsaspora owczarzaki suggests a premetazoan function for the Hippo pathway in multicellular morphogenesis
Authors: Phillips Jonathan E , Santos Maribel , Kanchwala Mohammed , Xing Chao , Pan Duojia 
Published: November 2021

ABSTRACTAnimal development is mediated by a surprisingly small set of canonical signaling pathways such as Wnt, Hedgehog, TGF-beta, Notch and Hippo pathways. Although once thought to be present only in animals, recent genome sequencing has revealed components of these pathways in the closest unicellular relatives of animals. These findings raise questions about the ancestral functions of these developmental pathways and their potential role in the emergence of animal multicellularity. Here, we provide the first functional characterization of any of these developmental pathways in unicellular organisms by developing techniques for genetic manipulation in Capsaspora owczarzaki, a close unicellular relative of animals that displays aggregative multicellularity. We then use these tools to characterize the Capsaspora ortholog of the Hippo signaling nuclear effector YAP/TAZ/Yorkie (coYki), a key regulator of tissue size in animals. In contrast to what might be expected based on studies in animals, we show that coYki is dispensable for cell proliferation but regulates cytoskeletal dynamics and the three-dimensional (3D) shape of multicellular structures. We further demonstrate that the cytoskeletal abnormalities of individual coYki mutant cells underlie the abnormal 3D shape of coYki mutant aggregates. Taken together, these findings implicate an ancestral role for the Hippo pathway in cytoskeletal dynamics and multicellular morphogenesis predating the origin of animal multicellularity, which was co-opted during evolution to regulate cell proliferation.
Explainability methods for differential gene analysis of single cell RNA-seq clustering models
Authors: Ciortan Madalina , Defrance Matthieu 
Published: November 2021

AbstractSingle-cell RNA sequencing (scRNA-seq) produces transcriptomic profiling for individual cells. Due to the lack of cell-class annotations, scRNA-seq is routinely analyzed with unsupervised clustering methods. Because these methods are typically limited to producing clustering predictions (that is, assignment of cells to clusters of similar cells), numerous model agnostic differential expression (DE) libraries have been proposed to identify the genes expressed differently in the detected clusters, as needed in the downstream analysis. In parallel, the advancements in neural networks (NN) brought several model-specific explainability methods to identify salient features based on gradients, eliminating the need for external models.We propose a comprehensive study to compare the performance of dedicated DE methods, with that of explainability methods typically used in machine learning, both model agnostic (such as SHAP, permutation importance) and model-specific (such as NN gradient-based methods). The DE analysis is performed on the results of 3 state-of-the-art clustering methods based on NNs. Our results on 36 simulated datasets indicate that all analyzed DE methods have limited agreement between them and with ground-truth genes. The gradients method outperforms the traditional DE methods, which en-courages the development of NN-based clustering methods to provide an out-of-the-box DE capability. Employing DE methods on the input data preprocessed by clustering method outperforms the traditional approach of using the original count data, albeit still performing worse than gradient-based methods.
Cryptococcus neoformans capsule regrowth experiments reveal dynamics of enlargement and architecture
Authors: Wear Maggie P. , Jacobs Ella , Wang Siqing , McConnell Scott , Bowen Anthony , Strother Camilla , Cordero Radames J.B. , Casadevall Arturo 
Published: November 2021

AbstractThe polysaccharide capsule of fungal pathogen Cryptococcus neoformans is a critical virulence factor that has historically evaded characterization. Polysaccharides remain attached to the cell as capsular polysaccharide (CPS) or are shed into the surroundings in the form of exopolysaccharide (EPS). While a great deal of study has been done examining the properties of EPS, far less is known about CPS. In this work, we detail the development of new physical and enzymatic methods for the isolation of CPS which can be used to explore the architecture of the capsule and removed capsular material. Sonication and glucanex digestion yield soluble CPS preparations, while French Press and modified glucanex digestion plus vortexing remove the capsule and cell wall producing polysaccharide aggregates that we call ‘capsule ghosts.’ The existence of capsule ghosts implies an inherent organization that allows it to exist independent of the cell wall surface. As sonication and glucanex digestion were noncytotoxic, it was possible to observe the cryptococcal cells rebuilding their capsule, revealing new insights into capsule architecture and synthesis consistent with a model in which the capsule is assembled from smaller polymers, which are then assemble into larger ones.ImportanceCharacterization of the cryptococcal polysaccharide capsule relies on methods of isolation for its in vitro study. This study demonstrates that the capsule is susceptible to physical and enzymatic removal. The application of new methods yields insights into the anatomy, modular nature, and architecture of the capsule with both soluble CPS preparations and ‘capsule ghosts.’ Together these insights inform on a long-standing debate modeling capsular assembly wherein our data shows that the capsule is assembled by smaller polymers added distally rather than by proximal addition or by polymers spanning the entire capsule radius.
Function of FMRP domains in regulating distinct roles of neuronal protein synthesis
Authors: D’Souza Michelle Ninochka , Ramakrishna Sarayu , Radhakrishna Bindushree K , Jhaveri Vishwaja , Ravindran Sreenath , Yeramala Lahari , Palakodeti Dasaradhi , Muddashetty Ravi S 
Published: November 2021

AbstractThe Fragile X Mental Retardation Protein (FMRP) is an RNA Binding Protein that regulates translation of mRNAs, essential for synaptic development and plasticity. FMRP interacts with a specific set of mRNAs and aids in their microtubule dependent transport and regulates their translation through its association with ribosomes. However, the biochemical role of individual domains of FMRP in forming neuronal granules and associating with microtubules and ribosomes is currently undefined. Here, we report that the C-terminus domain of FMRP is sufficient to bind to ribosomes as well as polysomes akin to the full-length protein. Furthermore, the C-terminus domain alone is essential and responsible for FMRP-mediated translation repression in neurons. However, FMRP-mediated puncta formation and microtubule association is favored by the synergistic combination of FMRP domains and not by individual domains. Interestingly, we show that the phosphorylation of hFMRP at Serine-500 is important in modulating the dynamics of translation by controlling ribosome/polysome association. This is a fundamental mechanism governing the size and number of FMRP puncta, which appear to contain actively translating ribosomes. Finally through the use of pathogenic mutations, we emphasize the hierarchy of the domains of FMRP in their contribution to translation regulation.
Activation of NLRP3 Inflammasome by Virus-like Particles of Human Polyomaviruses in Macrophages
Authors: Lučiūnaitė Asta , Dalgėdienė Indrė , Žilionis Rapolas , Mašalaitė Kristina , Norkienė Milda , Šinkūnas Andrius , Gedvilaitė Alma , Kučinskaitė-Kodzė Indrė , Žvirblienė Aurelija 
Published: November 2021

AbstractViral antigens can activate phagocytes inducing inflammation but the mechanisms are barely explored. This study aimed to investigate the capability of viral oligomeric proteins of different structure to induce inflammatory response in macrophages. Human THP-1 cell line was used to prepare macrophages which were treated with filamentous nucleocapsid-like particles (NLPs) of paramyxoviruses and spherical virus-like particles (VLPs) of human polyomaviruses. The effects of viral proteins on cell viability, pro-inflammatory cytokines’ production and formation of NLRP3 inflammasome components, ASC specks, were investigated. Filamentous NLPs did not induce inflammation markers while spherical VLPs mediated inflammatory response followed by NLRP3 inflammasome activation. Inhibitors of cathepsins and K+efflux decreased IL-1β levels and cell death indicating a complex inflammasome activation process. Similar activation pattern was observed in primary human macrophages treated with VLPs. Single cell RNAseq analysis of THP-1 cells revealed several cell activation states characterized by high expression of inflammation-related genes. This study provides new insights into interaction of viral proteins with innate immune cells and suggests that structural properties of oligomeric proteins may define cell activation pathways.
Predicting human decision making in psychological tasks with recurrent neural networks
Authors: Lin Baihan , Bouneffouf Djallel , Cecchi Guillermo 
Published: November 2021

AbstractUnlike traditional time series, the action sequences of human decision making usually involve many cognitive processes such as beliefs, desires, intentions and theory of mind, i.e. what others are thinking. This makes predicting human decision making challenging to be treated agnostically to the underlying psychological mechanisms. We propose to use a recurrent neural network architecture based on long short-term memory networks (LSTM) to predict the time series of the actions taken by the human subjects at each step of their decision making, the first application of such methods in this research domain. In this study, we collate the human data from 8 published literature of the Iterated Prisoner’s Dilemma comprising 168,386 individual decisions and postprocess them into 8,257 behavioral trajectories of 9 actions each for both players. Similarly, we collate 617 trajectories of 95 actions from 10 different published studies of Iowa Gambling Task experiments with healthy human subjects. We train our prediction networks on the behavioral data from these published psychological experiments of human decision making, and demonstrate a clear advantage over the state-of-the-art methods in predicting human decision making trajectories in both single-agent scenarios such as the Iowa Gambling Task and multi-agent scenarios such as the Iterated Prisoner’s Dilemma. In the prediction, we observe that the weights of the top performers tends to have a wider distribution, and a bigger bias in the LSTM networks, which suggests possible interpretations for the distribution of strategies adopted by each group.Author summaryThe challenge of predicting human decision is important for many application domains like economy, marketing and artificial intelligence. But the domain where the human behavior modeling is especially crucial is psychology, where the goal is to describe, explain and predict these behaviors. Within this domain, creating agents that effectively mimic human decision making is particularly important. However, despite the many behavioral tasks and analytical methods developed to simulate the process of human decision making in real situations, there have not been a predictive model that can well predict the human decision making trajectories in these psychological tasks. In this predictive modeling problem, we propose to use the long short-term memory networks (LSTM), a popular recurrent neural network architecture and effectively predict the time series of the actions taken by the human subjects at each step of their decision making in both the Iowa Gambling Task, a single-agent game with monetary reward, and the Iterated Prisoner’s Dilemma, a complex multi-agent social game with non-monetary capital at stake. To the best of our knowledge, this is the first application of such methods in this research domain.
Improved two-photon imaging of GPCR-based optogenetic neurotransmitter sensors using orthogonally polarized excitation
Authors: Pulin Mauro , Stockhausen Kilian E. , Masseck Olivia Andrea , Kubitschke Martin , Busse Björn , Wiegert J. Simon , Oertner Thomas G. 
Published: November 2021

AbstractFluorescent proteins such as GFP are best excited by light that is polarized parallel to the dipole axis of the fluorophore. In most cases, fluorescent proteins are randomly oriented, resulting in unbiased images even when polarized light is used for excitation, e.g. in two-photon microcopy. Here we reveal a surprisingly strong polarization sensitivity in a class of GPCR-based neurotransmitter sensors where the fluorophore is anchored on both ends. In tubular structures such as dendrites, this effect led to a complete loss of membrane signal in dendrites running parallel to the polarization direction of the excitation beam. Our data reveal a major problem for two-photon measurements of neurotransmitter concentration that has not been recognized by the neuroscience community. To remedy the sensitivity to dendritic orientation, we designed an optical device that generates interleaved pulse trains of orthogonal polarization, removing the orientation bias from images. The passive device, which we inserted in the beam path of an existing two-photon microscope, also removed the strong direction bias in second harmonic generation (SHG) images. We conclude that for optical measurements of transmitter concentration with GPCR-based sensors, orthogonally polarized excitation is essential.
Influence of the extracellular domain size on the dynamic behavior of membrane proteins
Authors: Gurdap Cenk Onur , Wedemann Linda , Sych Taras , Sezgin Erdinc 
Published: November 2021

ABSTRACTThe dynamic behavior of plasma membrane proteins mediates various cellular processes such as cellular motility, communication, and signaling. It is widely accepted that the dynamics of the membrane proteins is determined either by the interactions of the transmembrane domain with the surrounding lipids or by the interactions of the intracellular domain with cytosolic components such as cortical actin. Although initiation of different cellular signaling events at the plasma membrane has been attributed to the extracellular domain (ECD) properties recently, the impact of ECDs on the dynamic behavior of membrane proteins is rather unexplored. Here, we investigate how the ECD properties influence protein dynamics in the lipid bilayer by reconstituting ECDs of different sizes or glycosylation in model membrane systems and analyzing ECD-driven protein sorting in lipid domains as well as protein mobility. Our data shows that increasing the ECD mass or glycosylation leads to a decrease in ordered domain partitioning and diffusivity. Our data reconciles different mechanisms proposed for the initiation of cellular signaling by linking the ECD size of membrane proteins with their localization and diffusion dynamics in the plasma membrane.SIGNIFICANCE STATEMENTWe studied how the size and glycosylation of the proteins influences their dynamic behavior in a lipid bilayer by reconstituting the ECDs of different sizes or glycosylation in model membrane systems and analyzing their sorting into lipid domains as well as their mobility. We observe that increasing the ECD apparent mass leads to a decrease in membrane ordered domain partitioning and diffusivity. Our data reconciles multiple mechanisms proposed for the initiation of cellular signaling by linking the ECD properties of membrane proteins with their localization and diffusion dynamics in the plasma membrane.
Mobilome-driven segregation of the resistome in biological wastewater treatment
Authors: de Nies Laura , Busi Susheel Bhanu , Kunath Benoit Josef , May Patrick , Wilmes Paul 
Published: November 2021

AbstractBiological wastewater treatment plants (BWWTP) are considered to be hotspots of evolution and subsequent spread of antimicrobial resistance (AMR). Mobile genetic elements (MGEs) promote the mobilization and dissemination of antimicrobial resistance genes (ARGs) and are thereby critical mediators of AMR within the BWWTP microbial community. At present, it is unclear whether specific AMR categories are differentially disseminated via bacteriophages (phages) or plasmids. To understand the segregation of AMR in relation to MGEs, we analyzed meta-omic (metagenomic, metatranscriptomic and metaproteomic) data systematically collected over 1.5 years from a BWWTP. Our results showed a core group of fifteen AMR categories which were found across all timepoints. Some of these AMR categories were disseminated exclusively (bacitracin) or primarily (aminoglycoside, MLS, sulfonamide) via plasmids or phages (fosfomycin and peptide), whereas others were disseminated equally by both MGEs. Subsequent expression- and protein-level analyses further demonstrated that aminoglycoside, bacitracin and sulfonamide resistance genes were expressed more by plasmids, in contrast to fosfomycin and peptide AMR expression by phages, thereby validating our genomic findings. Longitudinal assessment further underlined these findings whereby the log2-fold changes of aminoglycoside, bacitracin and sulfonamide resistance genes were increased in plasmids, while fosfomycin and peptide resistance showed similar trends in phages. In the analyzed communities, the dominant taxon Candidatus Microthrix parvicella was a major contributor to several AMR categories whereby its plasmids primarily mediated aminoglycoside resistance. Importantly, we also found AMR associated with ESKAPEE pathogens within the BWWTP, for which MGEs also contributed differentially to the dissemination of ARGs. Collectively our findings pave the way towards understanding the segmentation of AMR within MGEs, thereby shedding new light on resistome populations and their mediators, essential elements that are of immediate relevance to human health.
Niche differences, not fitness differences, explain coexistence across ecological groups
Authors: Buche Lisa , Spaak Jurg W. , Jarillo Javier , De Laender Frederik 
Published: November 2021

AbstractUnderstanding the drivers of species coexistence is an important objective in ecology. Yet, the multitude of methods to study coexistence hampers cross-community comparisons. Here, we standardized niche and fitness differences (i.e how species limit themselves compared to others and their competitive ability, respectively) across 1018 species pairs to investigate species coexistence across ecological groups and methodological settings (experimental setup, natural co-occurrence, population model used, and growth method). We find that, first, coexistence is driven by large niche differences, not by small fitness differences. Second, species group into clear clusters of coexisting and non-coexisting species along the niche axis. Finally, these clusters are not driven by ecological or methodological settings. This suggests differences between coexisting and non-coexisting communities transcending those measured in our empirical systems. Overall, our results show that species coexistence is mainly influenced by mechanisms acting on niche differences.
A general design of caging-group free photoactivatable fluorophores for live-cell nanoscopy
Authors: Lincoln Richard , Bossi Mariano L. , Remmel Michael , D’Este Elisa , Butkevich Alexey N. , Hell Stefan W. 
Published: November 2021

ABSTRACTThe controlled switching of fluorophores between non-fluorescent and fluorescent states is central to every superresolution fluorescence microscopy (nanoscopy) technique, and the exploration of radically new switching mechanisms remains critical to boosting the performance of established, as well as emerging superresolution methods. Photoactivatable dyes offer significant improvements to many of these techniques, but often rely on photolabile protecting groups that limit their applications. Here we describe a general method to transform 3,6-diaminoxanthones into caging-group free photoactivatable fluorophores. These photoactivatable xanthones (PaX) assemble rapidly and cleanly into highly fluorescent, photo- and chemically stable pyronine dyes upon irradiation with light. The strategy is extendable to carbon- and silicon-bridged xanthone analogs, yielding a new family of photoactivatable labels spanning much of the visible spectrum. Our results demonstrate the versatility and utility of PaX dyes in fixed and live-cell fluorescence microscopy, and both coordinate-targeted stimulated emission depletion (STED) and coordinate-stochastic single-molecule localization superresolution microscopy (SMLM).