bluuebunny/crossref_metadata_2025_split huggingface dataset:
CRISPR-Cas provides limited phage immunity to a prevalent gut bacterium in gnotobiotic mice
Authors: Rasmussen Torben Sølbeck , Koefoed Anna Kirstine , Deng Ling , Muhammed Musemma K. , Rousseau Geneviève M. , Kot Witold , Sprotte Sabrina , Neve Horst , Franz Charles M.A.P. , Hansen Axel Kornerup , Vogensen Finn Kvist , Moineau Sylvain , Nielsen Dennis Sandris 
Published: May 2022

AbstractMany prokaryotes harbor the adaptive CRISPR-Cas system, which stores small nucleotide fragments from previous invasions of nucleic acids via viruses or plasmids. This molecular archive blocks further invaders carrying identical or similar nucleotide sequences. However, very few of these systems have been experimentally confirmed to be active in gut bacteria. Here, we experimentally demonstrate that the type I-C CRISPR-Cas system of the prevalent gut bacterium Eggerthella lenta can specifically target and cleave foreign DNA in vitro by using a plasmid transformation assay. We also show that the CRISPR-Cas system acquires new immunities (spacers) from the genome of a virulent E. lenta phage using traditional phage-assays in vitro but also in vivo using gnotobiotic (GB) mice. An increased number of spacer acquisition events were observed when E. lenta was exposed to a low multiplicity of infection in vitro, and three phage genes were found to contain protospacer hotspots. Interestingly, much less new spacer acquisitions were detected in vivo than in vitro. Longitudinal analysis of phage-bacteria interactions showed sustained coexistence in the gut of GB mice, with phage abundance being approximately one log higher than the bacteria. Our findings show that while the type I-C CRISPR-Cas system is active in vitro and in vivo, a highly virulent phage in vitro was still able co-exist with its bacterial host in vivo. Taken altogether, our results suggest that the CRISPR-Cas defense system of E. lenta provides only partial immunity in the gut.
Succinylated lysine residue prediction revisited
Authors: Ahmed Shehab Sarar , Rifat Zaara Tasnim , Rahman Mohammad Saifur , Rahman M. Sohel 
Published: May 2022

AbstractMotivationLysine succinylation is a kind of post-translational modification (PTM) which plays a crucial role in regulating the cellular processes. Aberrant succinylation may cause inflammation, cancers, metabolism diseases and nervous system diseases. The experimental methods to detect succinylation sites are time-consuming and costly. This thus calls for computational models with high efficacy and attention has been given in the literature for developing such models, albeit with only moderate success in the context of different evaluation metrics. One important aspect in this context is the biochemical and physicochemical properties of amino acids, which appear to be useful as features for such computational predictors. However, some of the existing computational models did not use the biochemical and physicochemical properties of amino acids, while some others used them without considering the inter-dependency among the properties.ResultsThe combinations of biochemical and physicochemical properties derived through our optimization process achieve better results than the results achieved by the combination of all the properties. We propose three deep learning architectures, CNN+Bi-LSTM (CBL), Bi-LSTM+CNN (BLC) and their combination (CBL_BLC). We find that CBL_BLC is outperforming the other two. Ensembling of different models successfully improves the results. Notably, tuning the threshold of the ensemble classifiers further improves the results. Upon comparing our work with other existing works on two datasets, we find that we successfully achieve better sensitivity and specificity through varying the threshold value.Availabilityhttps://github.com/Dariwala/Succinylation-with-biophysico-and-deep-learningContactmsrahman@cse.buet.ac.bd
Reduced sphingolipid biosynthesis modulates proteostasis networks to enhance longevity
Authors: Hepowit Nathaniel L. , Blalock Eric , Lee Sangderk , MacGurn Jason A. , Dickson Robert C. 
Published: May 2022

ABSTRACTAs the elderly population increases, chronic, age-associated diseases are challenging healthcare systems around the world. Nutrient limitation is well known to slow the aging process and improve health. Regrettably, practicing nutrient restriction to improve health is unachievable for most people. Alternatively, pharmacological strategies are being pursued including myriocin which increases lifespan in budding yeast. Myriocin impairs sphingolipid synthesis, resulting in lowered amino acid pools which promote entry into a quiescent, long-lived state. Here we present transcriptomic data during the first 6 hours of drug treatment that improves our mechanistic understanding of the cellular response to myriocin and reveals a new role for ubiquitin in longevity. Previously we found that the methionine transporter Mup1 traffics to the plasma membrane normally in myriocin-treated cells but is not active and undergoes endocytic clearance. We now show that UBI4, a gene encoding stressed-induced ubiquitin, is vital for myriocin-enhanced lifespan. Furthermore, we show that Mup1 fused to a deubiquitinase domain impairs myriocin-enhanced longevity. Broader effects of myriocin treatment on ubiquitination are indicated by our finding of a significant increase in K63-linked ubiquitin polymers following myriocin treatment. Although proteostasis is broadly accepted as a pillar of aging, our finding that ubiquitination of an amino acid transporter promotes longevity in myriocin-treated cells is novel. Addressing the role of ubiquitination/deubiquitination in longevity has the potential to reveal new strategies and targets for promoting healthy aging.
Hematopoietic stem cells are a reservoir for trained immunity in autoimmune disease
Authors: Mills Taylor S. , Kain Bailee , Burchill Matt A. , Danis Etienne , Culp-Hill Rachel , Goodspeed Andrew , Ferrara Sarah , Roede James R. , D’Alessandro Angelo , King Katherine Y. , Pietras Eric M. 
Published: May 2022

SUMMARYTrained immunity (TI) has been speculated to serve as a contributor to autoimmune disease (AD) pathogenesis via generation of hyper-inflammatory myeloid cells. Using a mouse model of systemic lupus erythematosus (SLE), we show that hematopoietic stem cells (HSC) constitute a transplantable, long-term reservoir for macrophages that exhibit features of TI, including increased Mycobacterium avium killing, inflammatory cytokine production, and augmented capacity to co-stimulate naive T cells. Strikingly, hematopoietic progenitor cells derived from these HSC exhibit unique molecular features characterized by reduced chromatin accessibility and transcription of metabolic genes, accompanied by reduced glycolysis and central carbon metabolism. Altogether, our data identify HSC as a functional unit of TI in chronic AD, establish increased T-cell costimulatory activity as a potentially pathogenic feature of TI in this setting, and show that macrophages inherit reduced metabolic activity from AD-exposed HSC, suggesting metabolic activation and TI can be decoupled. Our findings thus implicate HSC as a long-term reservoir for TI that could contribute to AD.
DNAscope: High accuracy small variant calling using machine learning
Authors: Freed Donald , Pan Renke , Chen Haodong , Li Zhipan , Hu Jinnan , Aldana Rafael 
Published: May 2022

AbstractWe present DNAscope, an accurate and efficient germline small-variant caller. DNAscope combines the robust and well-established preprocessing and assembly mathematics of the GATK’s HaplotypeCaller with a machine-learned genotyping model. Benchmarks of DNAscope and DNAseq (Sentieon’s GATK-matching germline variant calling pipeline) demonstrate that DNAscope achieves superior SNP and insertion/deletion accuracy with reduced computational cost.
Artificial Alzheimer’s – visualizing the process of memory decay, confusion and death in a simple Neural Network Model of Associative Memory
Authors: Gustafsson Lennart 
Published: May 2022

AbstractThis paper analyzes the behaviour of Alzheimer’s disease simulation in artificial neural networks and thereby suggests a new possible diagnosis for Alzheimer. Alzheimer’s disease is one of the most common diseases, increasing severity over time. Despite its high prevalence and thousands of yearly publications in this area, no cure has been found to date and early detection is one of the most important factor towards fighting the disease and possibly finding a cure. This paper analyses the behaviour of simulated Alzheimer in Hopfield memories and observes that the main factor influenced by the loss of connections is the time needed to recognize distorted symbols - while the recognition performance stays surprisingly high for a long time. Hence, I suggest a new early diagnosis approach which is based on slightly distorted elements (e.g., characters) and measures the time needed to perform the task, instead of just focusing on the subject’s recognition performance. This insight could have a large impact to future diagnose setups, once being validated in a clinical study.
Rab11 regulates autophagy at dendritic spines in an mTOR- and NMDA-dependent manner
Authors: Janusz-Kamińska Aleksandra , Brzozowska Agnieszka , Tempes Aleksandra , Urbanska Malgorzata , Blazejczyk Magdalena , Miłek Jacek , Zeng Juan , Kisielewska Katarzyna , Jaworski Jacek 
Published: May 2022

AbstractSynaptic plasticity is a process that shapes neuronal connections during neurodevelopment, learning, and memory. Autophagy is a mechanism that allows cells to degrade their unnecessary or dysfunctional components. Autophagosomes appear at dendritic spines in response to plasticity-inducing stimuli. Autophagy defects contribute to altered dendritic spine development, autistic-like behavior in mice, and neurological disease. While several studies explored the involvement of autophagy in synaptic plasticity, the steps preceding autophagosome emergence at the postsynapse remain unknown. Here we show a postsynaptic association of autophagy-related protein 9A (Atg9A), known to be involved in the initial stages of autophagosome formation, with Rab11, a small GTPase that regulates endosomal trafficking. Rab11 activity is necessary for the maintenance of Atg9A-positive structures at dendritic spines. Inhibition of mTOR increased Rab11 and Atg9A interaction and increased the emergence of autophagosomes in dendritic spines when coupled to NMDA receptor stimulation. Dendritic spines with newly formed autophagosomes were more resistant to NMDA-induced morphologic change. These results collectively suggest that autophagy initiation in dendritic spines depends on an activity-dependent Rab11a-Atg9A interaction regulated by mTOR.
Design of a mucin-selective protease for targeted degradation of cancer-associated mucins
Authors: Pedram Kayvon , Shon D. Judy , Tender Gabrielle S. , Mantuano Natalia R. , Northey Jason J. , Metcalf Kevin J. , Wisnovsky Simon P. , Riley Nicholas M. , Forcina Giovanni C. , Malaker Stacy A. , Kuo Angel , George Benson M. , Miller Caitlyn L. , Casey Kerriann M. , Vilches-Moure José G. , Weaver Valerie M. , Laübli Heinz , Bertozzi Carolyn R. 
Published: May 2022

AbstractTargeted protein degradation is an emerging strategy for the elimination of classically undruggable proteins. Here, to expand the landscape of substrates that can be selectively degraded, we designed degraders which are dependent on both peptide sequence and glycosylation status of the target protein. We applied this approach to mucins, O-glycosylated proteins that drive cancer progression through biophysical and immunological mechanisms. Engineering of a bacterial mucin-selective protease yielded a variant for fusion to a cancer antigen-binding nanobody. The resulting conjugate selectively degraded mucins on cancer cells, promoted cell death in culture models of mucin-driven growth and survival, and reduced tumor growth in murine models of breast cancer progression. This work establishes a blueprint for the development of biologics which degrade specific glycoforms of cell surface proteins.
Minimally invasive delivery of peptides to the spinal cord for behavior modulation
Authors: Gao Zhenghong , David Eric T. , Leong Tiffany W. , Li Xiaoqing , Cai Qi , Mwirigi Juliet , Giannotta Monica , Dejana Elisabetta , Wiggins John , Krishnagiri Sharada , Bachoo Robert M. , Price Theodore J. , Qin Zhengpeng 
Published: May 2022

AbstractThe blood-spinal cord barrier (BSCB) tightly regulates molecular transport from the blood to the spinal cord. Herein, we present a novel approach for transient modulation of BSCB permeability and localized delivery of peptides into the spinal cord for behavior modulation with high spatial resolution. This approach utilizes optical stimulation of vasculature-targeted nanoparticles and allows delivery of BSCB-nonpermeable molecules into the spinal cord without significant glial activation or impact on animal locomotor behavior. We demonstrate minimally invasive light delivery into the spinal cord using an optical fiber and BSCB permeability modulation in the lumbar region. Our method of BSCB modulation allows delivery of bombesin, a centrally-acting and itch-inducing peptide, into the spinal cord and induces a rapid and transient increase in itching behaviors in mice. This minimally invasive approach enables behavior modulation without genetic modifications and is promising for delivering a wide range of biologics into the spinal cord for behavior modulation and potentially therapy.Significance StatementSpinal cord diseases and disorders are common and cause significant disability, including chronic pain, paralysis, cognitive impairment, and mortality. The blood-spinal cord barrier is a considerable challenge for delivery by systemic therapeutic administration. We developed an optical approach for effectively and safely delivering molecules to the spinal cord to overcome this barrier. The fiberoptic method is minimally invasive and overcomes challenges that previous technologies face, including the complicated bone structure and standing waves that complicate BSCB opening using ultrasound. Optical stimulation offers unprecedented spatial resolution for the precise delivery in intricate spinal cord structures. Significantly, our approach modulates animal behavior (i.e., itch) without genetic modifications and demonstrates the potential for delivery of biologics such as peptides into the spinal cord.
Rudimentary Structure-Activity-Relationship study of the MMV Pathogen Box compound MMV675968 (2,4-diaminoquinazoline) unveils novel inhibitors of Trypanosoma brucei brucei DHFR enzyme
Authors: Dize Darline , Tata Rolland , Keumoe Rodrigue , Toghueo Rufin Marie Kouipou , Tchatat Mariscal Brice , Njanpa Cyrille Ngansop , Tchuenguia Vianey Claire , Yamthe Lauve Tchokouaha , Fokou Patrick Valere Tsouh , Laleu Benoît , Duffy James , Bishop Ozlem Tastan , Boyom Fabrice Fekam 
Published: May 2022

AbstractNew drugs are urgently needed for the treatment of human African trypanosomiasis (HAT). In line with our quest for dihydrofolate reductase (DHFR) inhibitors in trypanosomes, a small library of analogs of the antitrypanosomal hit (MMV675968) available at MMV as solid materials was screened for antitrypanosomal activity. In silico confirmation of two potent antitrypanosomal analogs as inhibitors of DHFR was achieved, together with elucidation of other antitrypanosomal modes of action. Overall, two analogs of the diaminoquinazoline derivative, MMV675968 reputed to inhibit the enzyme DHFR, displayed approximately 40-fold and 60-fold more potency and selectivity than the parent hit, respectively (MMV1578445 (10): IC50 = 0.045 µM, SI=1737; MMV1578467 (7): IC50 = 0.06 µM; SI=412). Analogs 7 and 10 were also strong binders of the DHFR enzyme, in all their accessible protonation states, and interacted with key DHFR ligand recognition residues Val32, Asp54, and Ile160. MMV1578445 (10) portrayed fast and irreversible trypanosomes growth arrest after 72 h and 4 h at IC99. Analogs 7 and 10 induced ferric iron reduction and DNA fragmentation or apoptosis induction, respectively. The two potent analogs endowed with suitable physicochemical properties are good candidates for further deciphering their potential as starting points for new drug development for HAT.Author summaryAfrican trypanosomiasis is a disease caused by parasites of the Trypanosoma brucei species which affect both humans and animals. We have adopted the fast-track drug repurposing approach to determine the antitrypanosomal activity of the open access MMV Pathogen Box compound library. The compound 2,4-diaminoquinazoline (MMV675998), known as a dihydrofolate reductase (DHFR) inhibitor was identified. Rudimentary structure-activity relationship investigation of this compound unveiled two highly active and selective derivatives MMV1578445 and MMV1578467 which were found to strongly inhibit the Trypanosoma brucei dihydrofolate reductase enzyme in silico. Besides, we demonstrated that analogues MMV1578445 and MMV1578467 could respectively reduce intrinsic ferric iron and induce apoptosis in trypanosomes. The two identified inhibitors of trypanosomes qualify as potential drug candidates that could be useful for future development as novel antitrypanosomal drugs.
Interplay between VSD, pore and membrane lipids in electromechanical coupling in HCN channels
Authors: Elbahnsi Ahmad , Cowgill John , Burtscher Verena , Wedemann Linda , Zeckey Luise , Chanda Baron , Delemotte Lucie 
Published: May 2022

AbstractHyperpolarized-activated and Cyclic Nucleotide-gated (HCN) channels are the only members of the voltage-gated ion channel superfamily in mammals that open upon hyperpolarization, conferring them pacemaker properties that are instrumental for rhythmic firing of cardiac and neuronal cells. Activation of their voltage-sensor domains (VSD) upon hyperpolarization occurs through a downward movement of the S4 helix bearing the gating charges, which triggers a break in the alpha-helical hydrogen bonding pattern at the level of a conserved Serine residue. Previous structural and molecular simulation studies had however failed to capture pore opening that should be triggered by VSD activation, presumably because of a low VSD/pore electromechanical coupling efficiency and the limited timescales accessible to such techniques. Here, we have used advanced modeling strategies, including enhanced sampling molecular dynamics simulations exploiting comparisons between non-domain swapped voltage-gated ion channel structures trapped in closed and open states to trigger pore gating and characterize electromechanical coupling in HCN1. We propose that the coupling mechanism involves the reorganization of the interfaces between the VSD helices, in particular S4, and the pore-forming helices S5 and S6, subtly shifting the balance between hydrophobic and hydrophilic interactions in a “domino effect” during activation and gating in this region. Remarkably, our simulations reveal state-dependent occupancy of lipid molecules at this emergent coupling interface, suggesting a key role of lipids in hyperpolarization-dependent gating. Our model provides a rationale for previous observations and a possible mechanism for regulation of HCN channels by the lipidic components of the membrane.
Alignment-free metal ion-binding site prediction from protein sequence through pretrained language model and multi-task learning
Authors: Yuan Qianmu , Chen Sheng , Wang Yu , Zhao Huiying , Yang Yuedong 
Published: May 2022

AbstractMore than one-third of the proteins contain metal ions in the Protein Data Bank. Correct identification of metal ion-binding residues is important for understanding protein functions and designing novel drugs. Due to the small size and high versatility of metal ions, it remains challenging to computationally predict their binding sites from protein sequence. Existing sequence-based methods are of low accuracy due to the lack of structural information, and time-consuming owing to the usage of multi-sequence alignment. Here, we propose LMetalSite, an alignment-free sequence-based predictor for binding sites of the four most frequently seen metal ions (Zn2+, Ca2+, Mg2+ and Mn2+). LMetalSite leverages the pretrained language model to rapidly generate informative sequence representations and employs transformer to capture long-range dependencies. Multi-task learning is adopted to compensate for the scarcity of training data and capture the intrinsic similarities between different metal ions. LMetalSite was shown to surpass state-of-the-art structure-based methods by more than 19.7%, 14.4%, 36.8%, and 12.6% in AUPR on the four independent tests, respectively. Further analyses indicated that the self-attention modules are effective to learn the structural contexts of residues from protein sequence.
Pangenome evolution in Escherichia coli is sequence type, not phylogroup, specific
Authors: Cummins Elizabeth A. , Hall Rebecca J. , Connor Chris , McInerney James O. , McNally Alan 
Published: May 2022

AbstractThe Escherichia coli species contains a diverse set of sequence types and there remain important questions regarding differences in genetic content within this population that need to be addressed. Pangenomes are useful vehicles for studying gene content within sequence types. Here, we analyse 21 E. coli sequence type pangenomes using comparative pangenomics to identify variance in both pangenome structure and content. We present functional breakdowns of sequence type core genomes and identify sequence types that are enriched in metabolism, transcription and cell membrane biogenesis genes. We also uncover metabolism genes that have variable core classification depending on which allele is present. Our comparative pangenomics approach allows for detailed exploration of sequence type pangenomes within the context of the species. We show that pangenome evolution is independent of phylogenetic signal at the phylogroup level, which may be a consequence of distinct sequence type-specific driving factors relating to ecology and pathogenic phenotype.Data SummarySupporting data and code have been provided within the article or through Supplementary Data files available at https://doi.org/10.6084/m9.figshare.19793758. Custom Python scripts used to perform analyses are available at github.com/lillycummins/InterPangenome unless otherwise stated in the text.
Correcting Modification-Mediated Errors in Nanopore Sequencing by Nucleotide Demodification and in silico Correction
Authors: Chiou Chien-Shun , Chen Bo-Han , Wang You-Wun , Kuo Nang-Ting , Chang Chih-Hsiang , Huang Yao-Ting 
Published: May 2022

AbstractThe accuracy of Oxford Nanopore Technology (ONT) sequencing has significantly improved thanks to new flowcells, sequencing kits, and basecalling algorithms. However, novel modifications untrained in the basecalling models can seriously reduce the quality. This paper reports a set of ONT-sequenced genomes with unexpected low quality (∼Q30) due to extensive new modifications. Demodification by whole-genome amplification (WGA) significantly improved the quality of all genomes (∼Q50-60) while losing the epigenome. We developed a computational method, Modpolish, for correcting modification-mediated errors without WGA. Modpolish produced high-quality genomes and uncovered the underlying modification motifs without loss of epigenome. Our results suggested that novel modifications are prone to ONT errors, which are correctable by WGA or Modpolish without additional short-read sequencing.