bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differentiating between infectious and non-infectious influenza A virus and coronavirus RNA levels using long-range RT-qPCR
Authors: Juozapaite Dovile , Rigby Charlotte V. , Olendraite Ingrida , Mathur Pankaj , Dhanorkar Kalyan , Hulle Vishalraj , Shah Tejas , Jadhao Vijeta , Mutha Shravan , Jalal Hamid , Gopal Vikram , te Velthuis Aartjan J.W. 
Published: November 2021

AbstractDuring the Coronavirus Disease 2019 (COVID-19) pandemic, residual SARS-CoV-2 genome and subgenomic RNA fragments were observed in recovered COVID-19 patients. The presence of such RNAs in the absence of live virus leads to incorrectly positive RT-qPCR results, potentially delaying medical procedures and quarantine release. We here propose a simple modification to turn commercial COVID-19 RT-qPCR protocols into long-range RT-qPCR assays that can differentiate between infectious and non-infectious influenza and coronavirus RNA levels. We find that the long-range RT-qPCR method has a sensitivity that is indistinguishable from a commercial Taq-Path COVID-19 RT-qPCR assay when tested on clinical samples taken withing 5 days of the onset of symptoms. In clinical samples taken at least 15 days after the onset of symptoms when patients had recovered from COVID-19, the modified RT-qPCR protocol leads to significantly fewer positive diagnoses. These findings suggest that the long-range RT-qPCR method may improve test-to-release protocols and expand the tools available for clinical COVID-19 diagnosis.ImportanceVarious molecular tests can detect viral RNA in clinical samples. However, these molecular tests cannot differentiate between RNA from infectious viruses or residual viral genome fragments that are not infectious. In several percent of COVID-19 patients, such residual viral RNAs can be detected long after recovery and the disappearance of infectious SARS-CoV-2. These “persistently-positive” RT-qPCR results are different from false-positive RT-qPCR results, which can be generated due to in vitro cross-reactivity or contaminations. However, the detection of RNA fragments leads to incorrect conclusions about the status of a COVID-19 patient and an incorrect diagnosis. We here modified the commercial Taq-Path COVID-19 RT-qPCR kit to make this test less sensitive to residual viral RNA genome fragments, reducing the likelihood that incorrect RT-qPCR results affect the treatment or quarantine status of recovered COVID-19 patients.
An outbreak inside an outbreak: rising incidence of carbapenem-resistant isolates during the COVID-19 pandemic. Report from a tertiary care center in Argentina
Authors: Castro Maximiliano Gabriel , Ubiergo Lucía , Vicino Macarena , Cuevas Gisel , Argarañá Fernanda 
Published: November 2021

ABSTRACTIntroductionCOVID-19 outbreaks have left us to deal with an aftermath on many fronts. In particular, disproportionate use of antibiotics, high ICU burden and longer in-hospital stays during the pandemic have been proposed to aggravate the emergency posed by carbapenem-resistant isolates (CRI), specially through carbapenemase production. However, there have been few reports worldwide regarding changes in CRI incidence and little latinamerican literature.ObjectiveWe set out to determine whether the incidence of CRI rose in a tertiary care center in Santa Fe, Argentina during the time period with active cases of COVID-19.MethodsAnalytic epidemiologic study retrospectively designed. Two time periods were defined: P1 (without active cases of COVID-19) from September, 2019 to August, 2020 and P2 (starting at the onset of the first wave of COVID-19 in this institution) from September, 2020 to June 2021. All clinically-relevant microbiological samples -those meant for diagnostic purposes-taken during the study period from patients in the Internal Medicine and Surgical wards as well as the Intensive Care Units were included. Incidence was calculated by dividing the number of CRI during each time frame by the count of patient-day during that same period, multiplied by a hundred.Results9,135 hospitalizations, 50,145 patient-days of analysis. A total of 7285 clinical samples were taken, with an overall positivity for CRI of 12.1% (n=883). Overall CRI incidence during P2 was 2.5 times higher than in P1 (2.52 vs 0.955/100 patient-days, p <0.001). ICU CRI incidence raised from 6.78 to 8.69/100 patient-days in P2 (p=0.006).ConclusionWe found alarming rates of CRI in our center, 2.5 times higher than previous to the first COVID-19 wave, similar to other reports worldwide. To our knowledge, this is one of the few Latin-American reports on the effect of the COVID-19 pandemic on CRI incidence.
Linking extreme seasonality and gene expression in arctic marine protists
Authors: Wutkowska Magdalena , Vader Anna , Logares Ramiro , Pelletier Eric , Gabrielsen Tove M. 
Published: November 2021

ABSTRACTAt high latitudes, strong seasonal differences in light availability affect marine organisms and restrict the timing of ecosystem processes. Marine protists are key players in Arctic aquatic ecosystems, yet little is known about their ecological roles over yearly cycles. This is especially true for the dark polar night period, which up until recently was assumed to be devoid of biological activity. A 12 million transcripts catalogue was built from 0.45-10 μm protist assemblages sampled over 13 months in a time series station in an arctic fjord in Svalbard. Community gene expression was correlated with seasonality, with light as the main driving factor. Transcript diversity and evenness were higher during polar night compared to polar day. Light-dependent functions had higher relative expression during polar day, except phototransduction. 64% of the most expressed genes could not be functionally annotated, yet up to 78% were identified in arctic samples from Tara Oceans, suggesting that arctic marine assemblages are distinct from those from other oceans. Our study increases understanding of the links between extreme seasonality and biological processes in pico- and nanoplanktonic protists. Our results set the ground for future monitoring studies investigating the seasonal impact of climate change on the communities of microbial eukaryotes in the High Arctic.
Human serum triggers antibiotic tolerance in Staphylococcus aureus
Authors: Ledger Elizabeth V. K. , Mesnage Stéphane , Edwards Andrew M. 
Published: November 2021

AbstractStaphylococcus aureus is a frequent cause of bloodstream infections. Treatment can be challenging, even when isolates appear to be drug susceptible, with high rates of persistent and relapsing infection. This is particularly the case with infections caused by methicillin resistant S. aureus (MRSA) strains, which are resistant to frontline antibiotics. To understand how the host environment influences treatment outcomes in MRSA infections, we studied the impact of human serum on staphylococcal susceptibility to daptomycin, an antibiotic of last resort. This revealed that serum triggered a very high degree of tolerance to daptomycin, as well as several other classes of antibiotics and antimicrobial peptides, including gentamicin, nitrofurantoin, vancomycin, nisin and gramicidin. Serum-induced daptomycin tolerance was due to two independent mechanisms. Firstly, the host defence peptide LL-37 present in serum induced tolerance by triggering the staphylococcal GraRS two component system. This led to increased cell wall accumulation that reduced access of daptomycin to its membrane target. Secondly, GraRS-independent changes to the membrane resulted in increased cardiolipin abundance that also contributed to daptomycin tolerance. When both mechanisms were blocked, serum exposed S. aureus cells were as susceptible to daptomycin as bacteria growing in laboratory media. These data demonstrate that host factors can significantly modulate antibiotic susceptibility via diverse mechanisms, which may in turn contribute to treatment failure. The inhibition of serum-induced cell wall accumulation by fosfomycin reduced tolerance, suggesting that this antibiotic may form a useful combination therapy with daptomycin.
PTP1B is an intracellular checkpoint that limits T cell and CAR T cell anti-tumor immunity
Authors: Wiede Florian , Lu Kun-Hui , Du Xin , Zeissig Mara N. , Xu Rachel , Goh Pei Kee , Xirouchaki Chrysovalantou E. , Hogarth Samuel J. , Greatorex Spencer , Sek Kevin , Daly Roger J. , Beavis Paul A. , Darcy Phillip K. , Tonks Nicholas K. , Tiganis Tony 
Published: November 2021

ABSTRACTImmunotherapies aimed at alleviating the inhibitory constraints on T cells have revolutionised cancer management. To date, these have focused on the blockade of cell surface checkpoints such as PD-1. Herein we identify protein-tyrosine-phosphatase 1B (PTP1B) as an intracellular checkpoint that is upregulated in T cells in tumors. We show that the increased PTP1B limits T cell expansion and cytotoxicity to contribute to tumor growth. T cell-specific PTP1B deletion increased STAT-5 signaling and this enhanced the antigen-induced expansion and cytotoxicity of CD8+T cells to suppress tumor growth. The pharmacological inhibition of PTP1B recapitulated the T cell-mediated repression of tumor growth and enhanced the response to PD-1 blockade. Furthermore, the deletion or inhibition of PTP1B enhanced the efficacy of adoptively-transferred chimeric-antigen-receptor (CAR) T cells against solid tumors. Our findings identify PTP1B as an intracellular checkpoint whose inhibition can alleviate the inhibitory constraints on T cells and CAR T cells to combat cancer.STATEMENT OF SIGNIFICANCETumors subvert anti-tumor immunity by engaging checkpoints that promote T-cell exhaustion. Here we identify PTP1B as an intracellular checkpoint and therapeutic target. We show that PTP1B is upregulated in intra-tumoral T-cells and that its deletion or inhibition enhances T-cell anti-tumor activity and increases CAR T-cell effectiveness against solid tumors.
Spontaneous rotations in epithelia as an interplay between cell polarity and boundaries
Authors: Lo Vecchio S. , Pertz O. , Szopos M. , Navoret L. , Riveline D 
Published: November 2021

ABSTRACTDirected flows of cellsin vivoare essential in morphogenesis. They shape living matter in phenomena involving cell mechanics and regulations of the acto-myosin cytoskeleton. However the onset of coherent motion is still poorly understood. Here we show that coherence is associated with spontaneous alignments of cell polarity by designing cellular rings of controlled dimensions. A tug-of-war between polarities dictates the onset of coherence, as assessed by tracking live cellular shapes and motions in various experimental conditions. In addition, we identify an internally driven constraint set by cellular acto-myosin cables at boundaries as essential to ensure coherence, and active force is generated as evaluated by the high RhoA activity. The cables are required to trigger coherence as shown by our numerical simulations based on a novel Vicsek-type model including free active boundaries. We quantitatively reproducein silicocoherence onsets and we predict criteria leading to coherence. Altogether, spontaneous coherent motion results from basic competitions between cell orientations and active cables at boundaries.
Cryo-EM structure of the human NKCC1 transporter reveals mechanisms of ion coupling and specificity
Authors: Neumann Caroline , Rosenbæk Lena Lindtoft , Flygaard Rasmus Kock , Habeck Michael , Karlsen Jesper Lykkegaard , Wang Yong , Lindorff-Larsen Kresten , Gad Hans Henrik , Hartmann Rune , Lyons Joseph , Fenton Robert A. , Nissen Poul 
Published: November 2021

AbstractThe sodium-potassium-chloride transporter NKCC1 (SLC12A2) performs Na+-dependent Cl−and K+ion uptake across plasma membranes. NKCC1 is important for regulating e.g. cell volume, hearing, blood pressure, and chloride gradients defining GABAergic and glycinergic signaling in brain. Here, we present a 2.6 Å resolution cryo-electron microscopy (cryo-EM) structure of human NKCC1 in the substrate-loaded (Na+, K+, 2 Cl−) and inward-facing conformation adopting an occluded state that has also been observed for the SLC6 type transporters MhsT and LeuT. Cl−binding at the Cl1 site together with the nearby K+ion provide a crucial bridge between the LeuT-fold scaffold and bundle domains. Cl−ion binding at the Cl2 site seems to undertake a structural role similar to a conserved glutamate of SLC6 transporters and may allow for chloride-sensitive regulation of transport. Supported by functional studies in mammalian cells and computational simulations we describe the Na+binding site and a putative Na+release pathway along transmembrane helix 5. The results provide insight into the structure-function relationship of NKCC1 with broader implications for other SLC12 family members.
Abnormal (hydroxy)prolines deuterium content redefines hydrogen chemical mass
Authors: Gharibi Hassan , Chernobrovkin Alexey , Eriksson Gunilla , Saei Amir Ata , Timmons Zena , Kitchener Andrew C. , Kalthoff Daniela , Lidén Kerstin , Makarov Alexander A. , Zubarev Roman A. 
Published: November 2021

ABSTRACTAnalysing the δ2H in individual amino acids of proteins extracted from vertebrates, we unexpectedly found in some samples, notably bone collagen from seals, more than twice as much deuterium in proline and hydroxyproline residues than in seawater. This corresponds to at least four times higher δ2H than in any previously reported biogenic sample. We ruled out diet as a plausible mechanism for such anomalous enrichment. This finding puts into question the old adage that you are what you eat.SUMMARYThe chemical mass of hydrogen is defined as an interval from the lowest to the highest content of deuterium 2H, hydrogen’s heavy stable isotope. Measurements of the deviations δ2H in the deuterium content from the standard (ocean water, δ2H = 0‰) are used to characterise biological samples, such as animal bone collagen. The results are often interpreted in terms of the trophic level and diet of the animal as well as prevailing climate during its lifetime. The majority of the published bone collagen δ2H data fall into a narrow δ2H range limited to ±100‰. Using novel analysis method, we unexpectedly found greatly higher δ2H values, up to 1500‰, in seal bone collagen. Such anomalous deuterium enrichment is detected only in two amino acid residues, proline and its derivative hydroxyproline, while other residues show much smaller δ2H values. Anomalously high δ2H values, albeit of lower magnitudes, are also found for these residues in other biological sources. This finding substantially expands the upper bound of the hydrogen chemical mass for biogenic sources. Since neither diet nor environment explain these mysteriously high enrichment levels amounting to more than twice deuterium content in sea water, our understanding of stable isotopes in nature, as well as the old adage “you are what you eat”, are put in question.
The C. albicans virulence factor Candidalysin polymerizes in solution to form membrane pores and damage epithelial cells
Authors: Russell Charles M. , Schaefer Katherine G. , Dixson Andrew , Gray Amber L.H. , Pyron Robert J. , Alves Daiane S. , Moore Nicholas , Conley Elizabeth A. , White Tommi A. , Do Thanh , King Gavin M. , Barrera Francisco N. 
Published: November 2021

AbstractThe pathogenic fungus Candida albicans causes severe invasive candidiasis. C. albicans infection requires the action of the virulence factor Candidalysin (CL), which damages the plasma membrane of the target human cells. However, the molecular mechanism that CL uses to permeabilize membranes is poorly understood. We employed complementary biophysical, modeling, microscopy, and cell biology methods to reveal that CL forms membrane pores using a unique molecular mechanism. Unexpectedly, it was observed that CL readily assembles into linear polymers in solution. The basic structural unit in polymer formation is a CL 8-mer, which is sequentially added into a string configuration. Finally, the linear polymers can close into a loop. Our data indicate that CL loops spontaneously insert into the membrane to become membrane pores. We identified a CL mutation (G4W) that inhibited the formation of polymers in solution and prevented formation of pores in different synthetic lipid membranes systems. Studies in epithelial cells showed that G4W CL failed to activate the danger response signaling pathway, a hallmark of the pathogenic effect of CL. These results indicate that CL polymerization in solution is a necessary step for the damage of cellular membranes. Analysis of thousands of CL pores by atomic force microscopy revealed the co-existence of simple depressions and complex pores decorated with protrusions. Imaging and modeling indicate that the two types of pores are formed by CL molecules assembled into alternate orientations. We propose that this structural rearrangement represents a maturation mechanism that might stabilize pore formation to achieve more robust cellular damage. Taken together, the data show that CL uses a previously unknown mechanism to damage membranes, whereby pre-assembly of CL loops in solution directly leads to formation of membrane pores. Our investigation not only unravels a new paradigm for the formation of membrane pores, but additionally identifies CL polymerization as a novel therapeutic target to treat candidiasis.
MicNet Toolbox: visualizing and deconstructing a microbial network
Authors: Favila Natalia , Madrigal-Trejo David , Legorreta Daniel , Sánchez-Pérez Jazmín , Espinosa-Asuar Laura , Souza Valeria 
Published: November 2021

AbstractUnderstanding both global and local patterns in the structure and interplay of microbial communities has been a fundamental question in ecological research. In this paper, we present a python toolbox that combines two emerging techniques that have been proposed as useful when analyzing compositional microbial data. On one hand, we introduce a visualization module that incorporates the use of UMAP, a recent dimensionality reduction technique that focuses on local patterns, and HDBSCAN, a clustering technique based on density. On the other hand, we have included a module that runs an enhanced version of the SparCC code, sustaining larger datasets than before, and we couple this with network theory analyses to describe the resulting co-occurrence networks, including several novel analyses, such as structural balance metrics and a proposal to discover the underlying topology of a co-occurrence network. We validated the proposed toolbox on 1) a simple and well described biological network of kombucha, consisting of 48 ASVs, and 2) using simulated community networks with known topologies to show that we are able to discern between network topologies. Finally, we showcase the use of the MicNet toolbox on a large dataset fromArchean Domes, consisting of more than 2,000 ASVs. Our toolbox is freely available as a github repository (https://github.com/Labevo/MicNetToolbox), and it is accompanied by a web dashboard (http://micnetapplb-1212130533.us-east-1.elb.amazonaws.com) that can be used in a simple and straightforward manner with relative abundance data.Author SummaryMicrobial communities are complex systems that cannot be wholly understood when studied by its individual components. Hence, global pattern analyses seem to be a promising complement to highly focused local approaches. Here, we introduce the MicNet toolbox, an open-source collection of several analytical methods for visualizing abundance data and creating co-occurrence networks for further analysis. We include two modules: one for visualization and one for network analysis based on graph theory. Additionally, we introduce an enhanced version of SparCC, a method to estimate correlations for co-occurrence network construction, that is faster and can support larger datasets. We performed method validations using simulated data and a simple biological network. Our toolbox is freely available in a github repository athttps://github.com/Labevo/MicNetToolbox, and it is accompanied by a web dashboard that could be easily accessed and manipulated by non-specialist users. With this implementation, we attempt to provide a simple and straightforward way to explore and analyze microbial relative abundance data.
Particle localization using local gradients and its application to nanometer stabilization of a microscope
Authors: Kashchuk Anatolii V. , Perederiy Oleksandr , Caldini Chiara , Gardini Lucia , Pavone Francesco S. , Negriyko Anatoliy M. , Capitanio Marco 
Published: November 2021

AbstractAccurate localization of single particles plays an increasingly important role in a range of biological techniques, including single molecule tracking and localization-based superresolution microscopy. Such techniques require fast and accurate particle localization algorithms as well as nanometer-scale stability of the microscope. Here, we present a universal method for three-dimensional localization of single labeled and unlabeled particles based on local gradient calculation of microscopy images. The method outperforms current techniques in high noise conditions, and it is capable of nanometer accuracy localization of nano- and micro-particles with sub-ms calculation time. By localizing a fixed particle as fiducial mark and running a feedback loop, we demonstrate its applicability for active drift correction in sensitive nanomechanical measurements such as optical trapping and superresolution imaging. A multiplatform open software package comprising a set of tools for local gradient calculation in brightfield and fluorescence microscopy is shared to the scientific community.
HA and M2 sequences alter the replication of 2013-16 H1 Live Attenuated Influenza Vaccine Infection in Human Nasal Epithelial Cell cultures
Authors: Canaday Laura M. , Resnick Jessica D. , Liu Hsuan , Powell Harrison , McCoy Alyssa M. , Nguyen Dat , Pekosz Andrew 
Published: November 2021

ABSTRACTFrom 2013-2016, the H1N1 component of live, attenuated influenza vaccine (LAIV) performed very poorly in contrast to the inactivated influenza vaccine. We utilized a primary, differentiated human nasal epithelial (hNEC) culture system to assess the replication differences between isogenic LAIVs containing the HA segment from either A/Bolivia/559/2013 (rBol), which showed poor vaccine efficacy, and A/Slovenia/2903/2015 (rSlov), which had restored reasonable vaccine efficacy. While there were minimal differences in infectious virus production in Madin-Darby Canine Kidney (MDCK) cells, the rSlov LAIV showed markedly improved replication in hNEC cultures at both 32°C and 37°C, demonstrating that the HA segment alone could impact LAIV replication. The rSlov-infected hNEC cultures showed stronger production of interferon and proinflammatory chemokines which might also be contributing to the increased overall vaccine effectiveness of the rSlov LAIV through enhanced recruitment and activation of immune cells. The introduction of an M2-S86A mutation had no positive effects on H1 LAIV replication in hNEC cultures, in contrast to the increased infectious virus production seen with that mutation in an H3 LAIV. No obvious defects in viral RNA packaging were detected, suggesting the HA function may be driving the differential infectious virus production in hNEC cultures. The use of physiologically relevant temperatures and primary cell cultures demonstrated that candidate LAIVs can replicate efficiently, which is a necessary property for effective vaccines.