bluuebunny/crossref_metadata_2025 huggingface dataset:
Dual oxic-anoxic co-culture enables direct study of host-anaerobe interactions at the airway epithelial interface
Authors: Moore Patrick J. , Wiggen Talia D. , Kent Leslie A. , Arif Sabrina J. , Lucas Sarah K. , Fletcher Joshua R. , Villareal Alex R. , Gilbertsen Adam , O’Grady Scott M. , Hunter Ryan C.
Published: March 2021

Strict and facultative anaerobic bacteria are widely associated with both acute and chronic airway disease. However, their potential role(s) in disease pathophysiology remain poorly understood due to inherent limitations of existing models and conflicting oxygen demands between anaerobes and host cells. To overcome these limitations, we optimized a dual oxic-anoxic culture (DOAC) platform that maintains an oxygen-limited microenvironment at the epithelial interface while host cells are oxygenated basolaterally. This approach enables host-bacterial co-culture for ∼24h, and here we demonstrate its utility via two applications. First, we show that anaerobe challenge results in epithelial mucus degradation, inflammatory marker gene expression, and enhanced pathogen colonization. Second, we combine DOAC with single cell RNA sequencing (scRNAseq) to reveal a cell type-specific transcriptional response of the airway epithelium to anaerobe infection. Together, these data illustrate the versatility of DOAC while revealing new insights into anaerobe-host interactions and their mechanistic contributions to airway disease pathophysiology.
Cell competition removes segmental aneuploid cells fromDrosophilaimaginal disc-derived tissues based on ribosomal protein gene dose
Authors: Ji Zhejun , Chuen Jacky , Kiparaki Marianthi , Baker Nicholas E.
Published: March 2021

Aneuploidy causes birth defects and miscarriages, occurs in nearly all cancers, and is a hallmark of aging. Individual aneuploid cells can be eliminated from developing tissues by unknown mechanisms. Cells with ribosomal protein (Rp) gene mutations are also eliminated, by cell competition with normal cells. BecauseRpgenes are spread across the genome, their copy number is a marker for chromosome aberrations. Elimination of imaginal disc cells with irradiation-induced genome damage often required cell competition genes. When defined chromosome regions were deleted, segmentally-aneuploid cells were eliminated by the RpS12-Xrp1 cell competition pathway in an apoptosis- dependent manner when they differed from neighboring cells inRpgene dose. Cells with normal doses of theRp(andeIF2γ) genes survived and differentiated adult tissues. Thus, cell competition, triggered by differences inRpgene dose between cells, is a significant mechanism for the elimination of aneuploid somatic cells, likely to contribute to preventing cancer.
Benzofuran sulfonates and small self-lipid antigens activate type II NKT cells via CD1d
Authors: Almeida CF , Smith D , Cheng T-Y , Harpur C , Batleska E , Nguyen T , Hilmenyuk T , Nguyen-Robertson CV , Reddiex SJJ , Van Rhijn I , Rossjohn J , Uldrich AP , Moody DB , Williams SJ , Pellicci DG , Godfrey DI
Published: March 2021

Natural Killer T (NKT) cells detect lipids presented by CD1d. Most studies focus on type I NKT cells that express semi-invariant αβ T cell receptors (TCR) and recognise α-galactosylceramides. However, CD1d also presents structurally distinct lipids to NKT cells expressing diverse TCRs (type II NKT cells) but our knowledge of the antigens for type II NKT cells is limited. An early study identified an NKT cell agonist, phenyl pentamethyldihydrobenzofuransulfonate (PPBF), which is notable for its similarity to common sulfa-drugs, but its mechanism of NKT-cell activation remained unknown. Here we demonstrate that a range of pentamethylbenzofuransulfonate (PBFs), including PPBF, activate polyclonal type II NKT cells from human donors. Whereas these sulfa drug-like molecules might have acted pharmacologically on cells, here we demonstrate direct contact between TCRs and PBF-treated CD1d complexes. Further, PBF-treated CD1d-tetramers identified type II NKT cell populations cells expressing αβ and γδTCRs, including those with variable and joining region gene usage (TRAV12-1–TRAJ6) that was conserved across donors. By trapping a CD1d-type II NKT TCR complex for direct mass spectrometric analysis, we detected molecules that allow binding of CD1d to TCRs, finding that both PBF and short-chain sphingomyelin lipids are present in these complexes. Furthermore, the combination of PPBF and short-chain sphingomyelin enhances CD1d tetramer staining of PPBF-reactive T cell lines over either molecule alone. This study demonstrates that non-lipidic small molecules, that resemble sulfa-drugs implicated in systemic hypersensitivity and drug allergy reactions, activate a polyclonal population of type II NKT cells in a CD1d-restricted manner.

Significance Statement

Whereas T cells are known to recognize peptide, vitamin B metabolite or lipid antigens, we identify several non-lipidic small molecules, pentamethylbenzofuransulfonates (PBFs), that activate a population of CD1d-restricted NKT cells. This represents a breakthrough in the field of NKT cell biology. This study also reveals a previously unknown population of PBF-reactive NKT cells in healthy individuals with stereotyped receptors that paves the way for future studies of the role of these cells in immunity, including sulfa-drug hypersensitivity.
A genetically encoded fluorescent biosensor for extracellular L-lactate
Authors: Nasu Yusuke , Murphy-Royal Ciaran , Wen Yurong , Haidey Jordan , Molina M. Rosana S. , Aggarwal Abhi , Zhang Shuce , Kamijo Yuki , Paquet Marie-Eve , Podgorski Kaspar , Drobizhev Mikhail , Bains Jaideep S. , Joanne Lemieux M. , Gordon Grant R. , Campbell Robert E.
Published: March 2021

To enable investigations of the emerging roles of cell-to-cell shuttling of L-lactate, we have developed an intensiometric green fluorescent genetically encoded biosensor for extracellular L-lactate. We demonstrate that this biosensor, designated eLACCO1.1, enables minimally invasive cellular resolution imaging of extracellular L-lactate in cultured mammalian cells and brain tissue.
Reciprocal recombination reflects sexual reproduction in symbiotic arbuscular mycorrhizal fungi
Authors: Mateus Ivan D. , Auxier Ben , Ndiaye Mam M. S. , Cruz Joaquim , Lee Soon-Jae , Sanders Ian R.
Published: March 2021

Arbuscular mycorrhizal fungi (AMF) are part of the most widespread fungal-plant symbiosis. They colonize at least 80% of plant species, promote plant growth and plant diversity. These fungi are multinucleated and contain either one or two haploid nuclear genotypes (monokaryon and dikaryon) identified by the alleles at a putative mating-type locus. This taxon has been considered as an ancient asexual scandal because of the lack of observable sexual structures. Despite identification of a putative mating-type locus and functional activation of genes related to mating when two isolates co-exist, it remains unknown if AMF take part in a mainly sexual life cycle.

We used publicly available genome sequences to test if dikaryon genomes display signatures of sexual reproduction in the form of reciprocal recombination patterns, or if they display signatures of parasexual reproduction involving gene conversion.

We used short-read and long-read sequence data to identify nucleus genotype-specific haplotypes within dikaryons and then compared them to orthologous gene sequences from related monokaryon isolates displaying the same putative MAT-types. We observed that these genotype-specific haplotypes display reciprocal recombination and not gene conversion.

These results are consistent with a sexual origin of the dikaryon rather than a parasexual origin and provides an important step to understand the life cycle of these globally important symbiotic fungi.
Genomic structure and diversity of oak populations in British Parklands
Authors: Nocchi Gabriele , Brown Nathan , Coker Tim , Plumb William , Stocks Jonathan , Denman Sandra , Buggs Richard
Published: March 2021

The two predominant oak species in Britain areQuercus robur(English or pedunculate oak) andQ. petraea(sessile oak). We sequenced the whole genomes of 386 oak trees from four British parkland sites and found over 50 million nuclear single nucleotide polymorphisms (SNPs), allowing us to identify 360Q. robur, tenQ. petraeaand 16 hybrid individuals using clustering methods. ComparingQ. roburandQ. petraeatrees from Attingham Park, we found that the nuclear genomes of the two species are largely undifferentiated but identified 81 coding regions exhibiting strong interspecific differentiation. The nuclear genomes of our 360Q. roburindividuals showed no clear differentiation among the four parkland sites. Scans for selective sweeps inQ. roburhighlighted regions containing genes with putative involvement in stress tolerance, one of which was moderately differentiated fromQ. petraea. Reconstructions of past effective population sizes suggested a long population size decline in bothQ. roburandQ. petraeaover the Pleistocene, but population growth after the last glacial maximum. We assembled the whole chloroplast genomes of 287Q. robur, 8Q. petraeaand 14 hybrid trees. In a phylogenetic network, these fell into five major haplotypes, which were shared among species but differed in frequency among parkland sites. We matched our chloroplast genome haplotypes to restriction enzyme fragment haplotypes identified in older studies that had surveyed ancient woodlands in Britain and much of Europe. This suggested that the parkland populations in our study derive from local seed sources.
3D Cell Neighbour Dynamics in Growing Pseudostratified Epithelia
Authors: Gómez Harold F. , Dumont Mathilde S. , Hodel Leonie , Vetter Roman , Iber Dagmar
Published: March 2021

During morphogenesis, epithelial sheets remodel into complex geometries. How cells dynamically organize their contact with neighbouring cells in these tightly packed tissues is poorly understood. We have used light-sheet microscopy of growing mouse embryonic lung explants, three-dimensional cell segmentation, and physical theory to unravel the principles behind 3D cell organization in growing pseudostratified epithelia. We find that cells have highly irregular 3D shapes and exhibit numerous neighbour intercalations along the apical-basal axis as well as over time. Despite the fluidic nature, the cell packing configurations follow fundamental relationships previously described for apical epithelial layers, i.e., Euler’s formula, Lewis’ law, and Aboav-Weaire’s law, at all times and across the entire tissue thickness. This arrangement minimizes the lateral cell-cell surface energy for a given cross-sectional area variability, generated primarily by the distribution and movement of nuclei. We conclude that the complex 3D cell organization in growing epithelia emerges from simple physical principles.
Multi-modal imaging reveals dynamic interactions ofStaphylococcus aureuswithin human neutrophils
Authors: Ho Yin Xin , Steele Elliot , Prince Lynne , Cadby Ashley
Published: March 2021

Staphylococcus aureusis an important human pathogen that causes a wide range of infections. Neutrophils are an essential component of our innate immune system and understanding S. aureus-neutrophil interactions on a sub-cellular level is crucial to developing new therapeutic strategies to promote immunity duringS. aureusinfections. To this end we have developed a multi-modal imaging platform capable of following host-pathogen processes in biological systems, this is achieved by switching imaging modalities between a low photo-toxicity and low resolution imaging modality through an increasing illumination intensity to achieve live super-resolution imaging. This novel imaging platform was applied to the study of human neutrophils infected byS. aureus. We show that we can image different infection stages ofS. aureusin live neutrophils with super resolution microscopy. We see evidence of binary fission occurring in intracellularS. aureuswithin a neutrophil.
TheMycobacterium tuberculosistransposon sequencing database (MtbTnDB): a large-scale guide to genetic conditional essentiality
Authors: Jinich Adrian , Zaveri Anisha , DeJesus Michael A. , Flores-Bautista Emanuel , Almada-Monter Ricardo , Smith Clare M. , Sassetti Christopher M. , Rock Jeremy M. , Ehrt Sabine , Schnappinger Dirk , Ioerger Thomas R. , Rhee Kyu Y.
Published: March 2021

Characterizing genetic essentiality across various conditions is fundamental for understanding gene function. Transposon sequencing (TnSeq) is a powerful technique to generate genome-wide essentiality profiles in bacteria and has been extensively applied toMycobacterium tuberculosis(Mtb). Dozens of TnSeq screens have yielded valuable insights into the biology of Mtb in vitro, inside macrophages, and in model host organisms. Despite their value, these Mtb TnSeq profiles have not been standardized or collated into a single, easily searchable database. This results in significant challenges when attempting to query and compare these resources, limiting our ability to obtain a comprehensive and consistent understanding of genetic conditional essentiality in Mtb. We address this problem by building a central repository of publicly available Mtb TnSeq screens, the Mtb transposon sequencing database (MtbTnDB). The MtbTnDB is a living resource that encompasses to date ≈150 standardized TnSeq screens, enabling open access to data, visualizations, and functional predictions through an interactive web app (www.mtbtndb.app). We conduct several statistical analyses on the complete database, such as demonstrating that (i) genes in the same genomic neighborhood have similar TnSeq profiles, and (ii) clusters of genes with similar TnSeq profiles are enriched for genes from similar functional categories. We further analyze the performance of machine learning models trained on TnSeq profiles to predict functional annotation of orphan genes in Mtb. By facilitating the comparison of TnSeq screens across conditions, the MtbTnDB will accelerate the exploration of conditional genetic essentiality, provide insights into the functional organization of Mtb genes, and help predict gene function in this important human pathogen.
A Biosensor for Detection of Indole Metabolites
Authors: Wang Jiefei , Zhang Chao , Childers W. Seth
Published: March 2021

The lack of diverse health-related biosensors limits the progress towards our understanding of how the microbiome metabolism impacts health. Microbially produced indole-3-aldehyde (I3A) has been associated with reducing inflammation in diseases such as ulcerative colitis by stimulating the aryl hydrocarbon receptor (AhR) pathway. We mined the protein database for gut microbiome metabolites’ sensors and developed a biosensor for I3A. We engineeredE. coliembedded with a single plasmid carrying a chimeric two-component system that detects I3A. Our I3A receptor characterization identified residues that contribute to the sensor’s high specificity in a range of 0.1-10 µM. The I3A biosensor opens the door to sensing indole metabolites produced at the host-microbe interface and provides new parts for synthetic biology applications.
Long-read sequencing of SARS-CoV-2 reveals novel transcripts and a diverse complex transcriptome landscape
Authors: Li-Pook-Than Jennifer , Banuelos Selene , Honkala Alexander , Sahoo Malaya K. , Pinsky Benjamin A. , Snyder Michael P.
Published: March 2021

Severe Acute Respiratory Syndrome Coronavirus 2, SARS-CoV-2 (COVID-19), is a positive single-stranded RNA virus with a 30 kb genome that is responsible for the current pandemic. To date, the genomes of global COVID-19 variants have been primarily characterized via short-read sequencing methods. Here, we devised a long-read RNA (IsoSeq) sequencing approach to characterize the COVID-19 transcript landscape and expression of its ∼27 coding regions. Our analysis identified novel COVID-19 transcripts including a) a short ∼65-70 nt 5’-UTR fused to various downstream ORFs encoding accessory proteins such as the envelope, ORF 8, and ORF 9 (nucleocapsid) proteins, that are relatively highly expressed, b) novel SNVs that are differentially expressed, whereby a subset are suggestive of partial RNA editing events, and c) SNVs at functional sites, whereby at least one is associated with a differentially expressed spike protein isoform. These previously uncharacterized COVID-19 isoforms, expressed genes, and gene variants were corroborated using ddPCR. Understanding this transcriptional complexity may help provide insight into the biology and pathogenicity of SARS-CoV-2 compared to other coronaviruses.
Binding of the Andes Virus Nucleocapsid Protein to RhoGDI Induces the Release and Activation of the Permeability Factor RhoA
Authors: Gorbunova Elena E. , Mackow Erich R.
Published: March 2021

Andes virus (ANDV) nonlytically infects pulmonary microvascular endothelial cells (PMECs) causing acute pulmonary edema termed hantavirus pulmonary syndrome (HPS). In HPS patients virtually every PMEC is infected, however the mechanism by which ANDV induces vascular permeability and edema remains to be resolved. The ANDV nucleocapsid (N) protein activates the GTPase, RhoA, in primary human PMECs causing VE-Cadherin internalization from adherens junctions and PMEC permeability. We found that ANDV N protein failed to bind RhoA, but co-precipitates RhoGDI (Rho GDP-dissociation inhibitor), the primary RhoA repressor that normally sequesters RhoA in an inactive state. ANDV N protein selectively binds the RhoGDI C-terminus (69-204) but fails to form ternary complexes with RhoA or inhibit RhoA binding to the RhoGDI N-terminus (1-69). However, we found that ANDV N protein uniquely inhibits RhoA binding to an S34D phosphomimetic RhoGDI mutant. Hypoxia and VEGF increase RhoA induced PMEC permeability by directing Protein Kinase Cα (PKCα) phosphorylation of S34 on RhoGDI. Collectively, ANDV N protein alone activates RhoA by sequestering and reducing RhoGDI available to suppress RhoA. In response to hypoxia and VEGF activated PKCα, ANDV N protein additionally directs the release of RhoA from S34-phosphorylated RhoGDI, synergistically activating RhoA and PMEC permeability. These findings reveal a fundamental edemagenic mechanism that permits ANDV to amplify PMEC permeability in hypoxic HPS patients. Our results rationalize therapeutically targeting PKCα and opposing Protein Kinase A (PKA) pathways that control RhoGDI phosphorylation as a means of resolving ANDV induced capillary permeability, edema and HPS.

Importance

HPS causing hantaviruses infect pulmonary endothelial cells causing vascular leakage, pulmonary edema and a 35% fatal acute respiratory distress syndrome (ARDS). Hantaviruses don’t lyse or disrupt the endothelium but dysregulate normal EC barrier functions and increase hypoxia directed permeability. Our findings reveal a novel underlying mechanism of EC permeability resulting from ANDV N protein binding to RhoGDI, a regulatory protein that normally maintains edemagenic RhoA in an inactive state and inhibits EC permeability. ANDV N sequesters RhoGDI and enhances the release of RhoA from S34 phosphorylated RhoGDI. These findings indicate that ANDV N induces the release of RhoA from PKC phosphorylated RhoGDI, synergistically enhancing hypoxia directed RhoA activation and PMEC permeability. Our data suggests inhibiting PKC and activating PKA phosphorylation of RhoGDI as mechanisms of inhibiting ANDV directed EC permeability and therapeutically restricting edema in HPS patients. These findings may be broadly applicable to other causes of ARDS.
SARS-CoV-2 surveillance in Norway rats (Rattus norvegicus) from Antwerp sewer system, Belgium
Authors: Colombo Valeria Carolina , Sluydts Vincent , Mariën Joachim , Broecke Bram Vanden , Van Houtte Natalie , Leirs Wannes , Jacobs Lotte , Iserbyt Arne , Hubert Marine , Heyndrickx Leo , Goris Hanne , Delputte Peter , De Roeck Naomi , Elst Joris , Boudewijns Robbert , Ariën Kevin K. , Leirs Herwig , Gryseels Sophie
Published: March 2021

Background

SARS-CoV-2 human-to-animal transmission can lead to the establishment of novel reservoirs and the evolution of new variants with the potential to start new outbreaks in humans.

Aim

We tested Norway rats inhabiting the sewer system of Antwerp, Belgium, for the presence of SARS-CoV-2 following a local COVID-19 epidemic peak. In addition, we discuss the use and interpretation of SARS-CoV-2 serological tests on non-human samples.

Methods

Between November and December 2020, Norway rat oral swabs, feces and tissues from the sewer system of Antwerp were collected to be tested by RT-qPCR for the presence of SARS-CoV-2. Serum samples were screened for the presence of anti-SARS-CoV-2 IgG antibodies using a Luminex microsphere immunoassay (MIA). Samples considered positive were then checked for neutralizing antibodies using a conventional viral neutralization test (cVNT).

Results

The serum of 35 rats was tested by MIA showing 3 potentially positive sera that were later shown to be negative by cVNT. All tissue samples of 39 rats analyzed tested negative for SARS-CoV-2 RNA.

Conclusion

This is the first study that evaluates SARS-CoV-2 infection in urban rats. We can conclude that the sample of 39 rats had never been infected with SARS-CoV-2. We show that diagnostic serology tests can give misleading results when applied on non-human samples. SARS-CoV-2 monitoring activities should continue due to the emergence of new variants prone to infect Muridae rodents.
Diversification ofB. subtilisduring experimental evolution onA. thalianaand the complementarity in root colonization of evolved subpopulations
Authors: Blake Christopher , Nordgaard Mathilde , Maróti Gergely , Kovács Ákos T.
Published: March 2021

The soil bacteriumBacillus subtilisis known to suppress pathogens as well as promote plant growth. However, in order to fully exploit the potential as natural fertilizer, we need a better understanding of the interactions betweenB. subtilisand plants. Here,B. subtiliswas examined for root colonization through experimental evolution onArabidopsis thaliana. The populations evolved rapidly, improved in root colonization and diversified into three distinct morphotypes. In order to better understand the adaptation that had taken place, single evolved isolates from the final transfer were randomly selected for further characterization, revealing changes in growth and pellicle formation in medium supplemented with plant polysaccharides. Intriguingly, certain evolved isolates showed improved root colonization only on the plant species they evolved on, but not on another plant species, namely tomato, suggestingA. thalianaspecific adaption paths. Finally, the mix performed better than the sum of its constituents in monoculture, which was demonstrated to be caused by complementarity effects. Our results suggest, that genetic diversification occurs in an ecological relevant setting on plant roots and proves to be a stable strategy for root colonization.

Significance Statement

Understanding how plant-growth-promoting rhizobacteria (PGPR) colonize plant roots is crucial to fully utilize their potential for agricultural applications. Here, we employ experimental evolution of the PGPRBacillus subtilisonArabidopsis thalianato study root colonization. We revealed that evolving populations rapidly improve in root colonization and diversify into distinct morphotypes. Notably, improved root colonization by evolved isolates was observed onA. thaliana, not on tomato. Moreover, isolates of distinct morphotypes interacted during root colonization and the mixture of morphotypes showed higher productivity than predicted. These findings suggest that genetic diversification might be a stable strategy to maximize root colonization.
Biochemical reconstitution defines new functions for membrane-bound glycosidases in assembly of the bacterial cell wall
Authors: Taguchi Atsushi , Walker Suzanne
Published: March 2021

The peptidoglycan cell wall is a macromolecular structure that encases bacteria and is essential for their survival. Proper assembly of the cell wall requires peptidoglycan synthases as well as membrane-bound cleavage enzymes that control where new peptidoglycan is made and inserted. We are only beginning to understand the roles of peptidoglycan cleavage enzymes in cell wall assembly. Previous studies have shown that two membrane-bound proteins inStreptococcus pneumoniae, here named MpgA and MpgB, are important in maintaining cell wall integrity. MpgA was predicted to be a lytic transglycosylase based on its homology toEscherichia coliMltG while the enzymatic activity of MpgB was unclear. Using nascent peptidoglycan substrates synthesizedin vitrofrom the peptidoglycan precursor Lipid II, we report that both MpgA and MpgB are muramidases. We show that replacing a single amino acid inE. coliMltG with the corresponding amino acid from MpgA results in muramidase activity, allowing us to predict from the presence of this amino acid that other putative lytic transglycosylases actually function as muramidases. Strikingly, we report that MpgA and MpgB cut nascent peptidoglycan at different positions along the sugar backbone relative to the reducing end. MpgA produces much longer peptidoglycan oligomers and we show that its cleavage site selectivity is controlled by the LysM-like subdomain, which is also present in MltG. We propose that MltG’s ability to complement loss of MpgA inS. pneumoniae despite performing different cleavage chemistry is because it can cleave nascent peptidoglycan at the same distance from the lipid anchor.
Resolving the Dynamic Motions of SARS-CoV-2 nsp7 and nsp8 Proteins Using Structural Proteomics
Authors: Courouble Valentine V. , Dey Sanjay Kumar , Yadav Ruchi , Timm Jennifer , Harrison Jerry Joe E. K. , Ruiz Francesc X. , Arnold Eddy , Griffin Patrick R.
Published: March 2021

Coronavirus (CoV) non-structural proteins (nsps) assemble to form the replication-transcription complex (RTC) responsible for viral RNA synthesis. nsp7 and nsp8 are important cofactors of the RTC, as they interact and regulate the activity of RNA-dependent RNA polymerase (RdRp) and other nsps. To date, no structure of full-length SARS-CoV-2 nsp7:nsp8 complex has been published. Current understanding of this complex is based on structures from truncated constructs or with missing electron densities and complexes from related CoV species with which SARS-CoV-2 nsp7 and nsp8 share upwards of 90% sequence identity. Despite available structures being solved using crystallography and cryo-EM representing detailed snapshots of the nsp7:nsp8 complex, it is evident that the complex has a high degree of structural plasticity. However, relatively little is known about the conformational dynamics of the complex and how it assembles to interact with other nsps. Here, the solution-based structural proteomic techniques, hydrogen-deuterium exchange mass spectrometry (HDX-MS) and crosslinking mass spectrometry (XL-MS), illuminate the structural dynamics of the SARS-CoV-2 full-length nsp7:nsp8 complex. The results presented from the two techniques are complementary and validate the interaction surfaces identified from the published three-dimensional heterotetrameric crystal structure of SARS-CoV-2 truncated nsp7:nsp8 complex. Furthermore, mapping of XL-MS data onto higher order complexes suggests that SARS-CoV-2 nsp7 and nsp8 do not assemble into a hexadecameric structure as implied by the SARS-CoV full-length nsp7:nsp8 crystal structure. Instead our results suggest that the nsp7:nsp8 heterotetramer can dissociate into a stable dimeric unit that might bind to nsp12 in the RTC without altering nsp7-nsp8 interactions.
Substrate mediated elastic coupling between motile cells modulates inter–cell interactions and enhances cell–cell contact
Authors: Bose Subhaya , Dasbiswas Kinjal , Gopinath Arvind
Published: March 2021

The mechanical micro–environment of cells and tissues influences key aspects of cell structure and function including cell motility. For proper tissue development, cells need to migrate, interact with other neighbouring cells and form contacts, each of which require the cell to exert physical forces. Cells are known to exert contractile forces on underlying soft substrates. These stresses result in substrate deformation that can affect migratory behavior of cells as well as provide an avenue for cells to sense each other and coordinate their motion. The role of substrate mechanics, particularly its stiffness, in such biological processesis therefore a subject of active investigation. Recent progress in experimental techniques have enabled key insights into pairwise mechanical interactions that control cell motility when they move on compliant soft substrates. Analysis and modeling of such systemsis however still in its nascent stages. Motivated by the role modeling is expected to play in interpreting, informing and guiding experiments, we build a biophysical model for cell migration and cell–cell interactions. Our focus is on situations highly relevant to tissue engineering and regenerative medicine –when substrate traction stresses induced by motile cells enable substrate deformation and serve as a medium of communication. Using a generalizable agent–basedmodel, we compute key metrics of cell motile behavior such as the number of cell–cell contacts over a given time, dispersion of cell trajectories, and probability of permanent cell contact, and analyze how these depend on a cell motility parameter and on substrate stiffness. Our results provide a framework towards modeling the manner in which cells may sense each other mechanically via the substrate and use this information to generate coordinated movements across much longer length scales. Our results also provide a foundation to analyze experiments on the phenomenon known as durotaxis where single cells move preferentially towards regions of high stiffness on patterned substrates.
Molecular basis for SPIN·DOC-Spindlin1 engagement and its role in transcriptional inhibition
Authors: Zhao Fan , Yang Fen , Feng Fan , Peng Bo , Bedford Mark T. , Li Haitao
Published: March 2021

Spindlin1 is a transcriptional coactivator with three Tudor-like domains, of which the first and second Tudors are engaged in histone methylation readout, while the function of the third Tudor is largely unknown. Recent studies revealed that the transcriptional co-activator activity of Spindlin1 could be attenuated by SPIN•DOC. Here we solved the crystal structure of SPIN•DOC-Spindlin1 complex, revealing that a hydrophobic motif, DOCpep3 (256-281), of SPIN•DOC interacts with Tudor 3 of Spindlin1 and completes its β-barrel fold. Massive hydrophobic contacts and hydrogen bonding interactions ensure a high affinity DOCpep3-Spindlin1 engagement with a bindingKdof 30 nM. Interestingly, we characterized two more K/R-rich motifs of SPIN•DOC, DOCpep1 (187-195) and DOCpep2 (228-239), which bind to Spindlin1 at lower affinities withKdvalues of 78 μM and 31 μM, respectively. Structural and binding studies revealed that DOCpep1 and DOCpep2 competitively bind to the aromatic cage of Spindlin1 Tudor 2 that is responsible for H3K4me3 readout. Although DOCpep3-Spindlin1 engagement is compatible with histone readout, an extended SPIN•DOC fragment containing DOCpep1 and DOCpep2 inhibits histone or TCF4 binding by Spindin1 due to introduced competition. This inhibitory effect is more pronounced for weaker binding targets but not for strong ones such as H3 “K4me3-K9me3” bivalent mark. Our RT-qPCR experiment showed that the removal of the hydrophobic motif or the K/R-rich region compromised the inhibitory effects of SPIN•DOC on Spindlin1-mediated transcriptional activation. In sum, here we revealed multivalent engagement between SPIN•DOC and Spindlin1, in which a hydrophobic motif acts as the primary binding site for stable SPIN•DOC-Spindlin1 association, while two more neighboring K/R-rich motifs further modulate the target selectivity of Spindlin1 via competitive inhibition, therefore attenuating the transcriptional co-activator activities of Spindlin1 through affecting its chromatin association.
Firm performance in the financial industry: the role of foreign entrants and their origin
Authors: Nguyen Dao Thi Hong
Published: March 2021

Purpose

This study aims to provide firm-level evidence on the relationship between the presence of financial services multinationals and indigenous counterparts’ performance, using a comprehensive sample of firms in the emerging financial industry in Vietnam.

Design/methodology/approach

This study uses the generalized method of moments with instrumental variables (IV/GMM) to deal with potential endogeneity problem. Of this technique, a pragmatic approach to constructing instruments is adopted, capitalizing on the geographical and industry segmentation of the local market. The empirical analyses also address statistical issues of the overall model significance, heteroskedasticity and multicollinearity.

Findings

The regression results reveal that foreign entrants have a positive and statistically significant association with indigenous firms’ labor productivity and the average wage, with a more pronounced impact on the latter. The increased entry of financial multinationals appears to be uncorrelated with indigenous firms’ profitability. The extended estimations also suggest that investor origin matters in determining spillover magnitude. The average estimate of Asian affiliates in the examined relationship is approximately half that of European affiliates, whereas foreign entrants originating from America show an insignificant role.

Originality/value

This study sheds light on the broader impacts of foreign financial affiliates by simultaneously exploring their impacts on three key dimensions of indigenous firm performance, namely, labor productivity, average wage and profitability. This paper also enriches the existing literature by disentangling the effects of foreign entrants from different regions of origin, which was largely neglected in the context of financial services multinationals.
Using social media comments to reduce alcohol purchase intentions: An online experiment
Authors: Noel Jonathan K.
Published: March 2021

Introduction

Alcohol advertising is prevalent on social media. The current study sought to identify effective message types to pair with social media alcohol ads to minimise purchase intentions associated with exposure.

Methods

A 6 (within) × 5 (between) randomised controlled experiment was conducted with n = 723 US participants. Participants viewed six unique social media alcohol ads and were randomised to view one of four message types (i.e. pro‐drinking comments, anti‐drinking comments, industry responsibility messages and health warning labels) associated with the ads or the control (i.e. no messages). Purchase intentions were measured after each ad exposure. Significant main and interactive effects were determined by two‐level, random intercept hierarchical linear models.

Results

Purchase intentions were significantly lower among participants who viewed anti‐drinking comments relative to the control (P = 0.022) and warning labels (P = 0.016). Purchase intentions were significantly greater among participants who viewed pro‐drinking comments and had a family history of alcohol use (P = 0.032) and among those who viewed warning labels and were previously exposed to alcohol depictions through family and friends' social media posts (P = 0.033).

Discussion and Conclusions

Anti‐drinking messages, written by social media users, may be effective at reducing alcohol purchase intentions when posted as social media comments. Current industry responsibility messages had no effect, and caution may be needed if warning labels are applied to ads in this medium.
Assessing liver stiffness with conventional cut‐off values overestimates liver fibrosis staging in patients who received the Fontan procedure
Authors: Cho Yuki , Kabata Daijiro , Ehara Eiji , Yamamoto Akira , Mizuochi Tatsuki , Mushiake Sotaro , Kusano Hironori , Kuwae Yuko , Suzuki Tsugutoshi , Uchida‐Kobayashi Sawako , Morikawa Hiroyasu , Amano‐Teranishi Yuga , Kioka Kiyohide , Jogo Atsushi , Isoura Yoshiharu , Hamazaki Takashi , Murakami Yosuke , Tokuhara Daisuke
Published: March 2021

Aim

Patients who undergo the Fontan procedure for complex congenital heart disease are prone to liver cirrhosis. Liver stiffness (LS) reflects liver fibrosis stage in patients with chronic viral hepatitis; however, its accuracy in predicting liver fibrosis stage in Fontan patients is controversial. We aimed to clarify the correlation between LS and liver fibrosis stage in Fontan patients.

Methods

Fifty‐eight Fontan patients were prospectively measured for LS with transient elastography. We undertook liver biopsy, cardiac catheterization, and laboratory tests in 22 of these patients (median age, 14.7 years; range, 9.9–32.1 years) with LS > 11.0 kPa (median, 19.2 kPa; range, 12.2–39.8 kPa); these elevated LS values suggest liver cirrhosis.

Results

Histologically, all patients showed mild‐to‐severe portal and sinusoidal fibrosis but no cirrhosis. Statistically, LS did not predict histological liver fibrosis scores (p = 0.175). Liver stiffness was not correlated with central venous pressure (p = 0.456) or with the hepatic venous pressure gradient (HVPG; p = 0.062), although the p value for HVPG was only slightly above the threshold for significance.

Conclusions

Fontan patients are prone to developing both portal and sinusoidal fibrosis. Liver stiffness could be influenced by HVPG, and using the conventional cut‐off values for LS overestimates and overtreats liver fibrosis in these patients.
The Kick-Smart Program: A Randomised Feasibility Trial Evaluating the Feasibility and Efficacy of a Primary-School Based Martial Arts Program Integrating Mathematics, Physical Fitness and Well-Being
Authors: Burt Louis David , Riley Nicholas , Parkes Robert John , Eather Narelle
Published: March 2021

The objective of this study was to evaluate the feasibility and efficacy of the ‘Kick-Smart’ martial arts programme using a randomised controlled-trial conducted in one Australian primary school. Kick-Smart involved children 9-11yrs (n= 46) randomised into treatment or wait-list control conditions. Kick-Smart consisted of 2x60min curriculum sessions/week for 6-weeks during school hours. Positive feedback was received from students and teachers regarding program enjoyment, perceived benefits and future plans. Significant treatment effects favouring the Kick-Smart group for muscular fitness and mathematics achievement demonstrates preliminary efficacy. Findings indicate Kick-Smart is feasible for delivery in a primary school setting and effective for improving selected fitness and academic outcomes. Further evidence for the effectiveness of Kick-Smart via a larger randomised control trial is recommended.
Four new species of Halozercon (Acari: Mesostigmata: Zerconidae) from South Siberia Mountains (Russia) with a key to all known species
Authors: MARCHENKO IRINA I.
Published: March 2021

Four new species of zerconid mites of the genus Halozercon are described and illustrated based on material collected from litter and soil in Altai and Tuva mountains, South Siberia, Russia—H. alataus sp. n., H. gryphus sp. n., H. kumir sp. n. and H. aesopi sp. n. Morphological characters for the new Halozercon species are given. A key for all known species of Halozercon is attached.
The green lacewing genus Anachrysa Hölzel, 1973 stat. nov. (Neuroptera: Chrysopidae) from China, with description of two new species
Authors: MA YUNLONG , LIU XINGYUE
Published: March 2021

A taxonomic study of the green lacewing genus Anachrysa Hölzel, 1973 from China is presented. Five species of Anachrysa are recorded from China. Two new species, Anachrysa lifashengi sp. nov. and Anachrysa luna sp. nov., which are described in this study, and three new combinations, i.e. Anachrysa holzeli (Wang & Yang, 1992) comb. nov., Anachrysa xiangana (Wang & Yang, 1992) comb. nov. and Anachrysa trigonia (Yang & Wang, 2005) comb. nov. are proposed. A key to species of Anachrysa from China is also provided.
Investigating Popular Mental Health Mobile Application Downloads and Activity During the COVID-19 Pandemic
Authors: Wang Xiaomei , Markert Carl , Sasangohar Farzan
Published: March 2021

Objective

This article analyzes the changes in downloads and activity of users of select popular mental health mobile applications (mHealth apps) during coronavirus disease 2019 (COVID-19).

Background

The outbreak of the COVID-19 crisis has shown a negative impact on public mental health. Mobile health has the potential to help address the psychological needs of existing and new patients during the pandemic and beyond.

Method

Downloads data of 16 widely used apps were analyzed. The quality of apps was reviewed using the Mobile Application Rating Scale (MARS) framework. Correlation analysis was conducted to investigate the relationship between app quality and app popularity.

Results

Among the 16 apps, 10 were meditational in nature, 13 showed increased downloads, with 11 apps showing above 10% increase in the downloads after the pandemic started. The popular apps were satisfactory in terms of functionality and esthetics but lacked clinical grounding and evidence base. There exists a gap between app quality and app popularity.

Conclusion

This study provided evidence for increased downloads of mental mHealth apps (primarily meditation apps) during the COVID-19 pandemic but revealed several gaps and opportunities to address deficiencies in evidence-based design, usability and effective assessment, and integration into current workflows.

Application

The COVID-19 pandemic is a potential turning point for mHealth applications for mental health care. Whereas the evidence suggests a need for alternative delivery of care, human factors and ergonomics methods should be utilized to ensure these tools are user-centered, easy to use, evidence-based, well-integrated with professional care, and used sustainably.
From Armenia to Poland ‘with love’s light wings’
Authors: Seymour Jasmine
Published: March 2021

On 30 July 2019, Yerevan State Chamber Theatre’s unconventional version of Romeo and Juliet was performed at the annual Gdańsk Shakespeare Theatre Festival in Poland, after successfully premiering in Yerevan, Armenia, in 2017. Following the overwhelming success of the production with local and international audiences and critics, invitations from other European festivals followed. When the current devastating restrictions imposed on theatres worldwide by the Covid-19 pandemic are finally lifted, the journey of the world’s best-known love story retold by this innovative theatre troupe will resume.
No clinically meaningful difference in 1-year patient-reported outcomes among major approaches for primary total hip arthroplasty
Authors:   The Cleveland Clinic OME Arthroplasty Group:, Bircher James B , Kamath Atul F , Piuzzi Nicolas S , Barsoum Wael K , Brooks Peter J , Hampton Robert J , Higuera Carlos A , Klika Alison , Krebs Viktor E , Mesko Nathan W , Molloy Robert M , Mont Michael A , Murray Trevor G , Muschler George F , Nickodem Robert J , Patel Preetesh D , Spindler Kurt P , Stearns Kim L , Strnad Gregory J , Suarez Juan C , Warren Jared A , Zajicheck Alexander , Bloomfield Michael R.
Published: March 2021

Background:

Debate continues around the most effective surgical approach for primary total hip arthroplasty (THA). This study’s purpose was to compare 1-year patient-reported outcome measures (PROMs) of patients who underwent direct anterior (DA), transgluteal anterolateral (AL)/direct lateral (DL), and posterolateral (PL) approaches.

Methods:

A prospective consecutive series of primary THA for osteoarthritis ( n = 2390) were performed at 5 sites within a single institution with standardised care pathways (20 surgeons). Patients were categorised by approach: DA ( n = 913; 38%), AL/DL ( n = 505; 21%), or PL ( n = 972; 41%). Primary outcomes were pain, function, and activity assessed by 1-year postoperative PROMs. Multivariable regression modeling was used to control for differences among the groups. Wald tests were performed to test the significance of select patient factors and simultaneous 95% confidence intervals were constructed.

Results:

At 1-year postoperative, PROMs were successfully collected from 1842 (77.1%) patients. Approach was a statistically significant factor for 1-year HOOS pain ( p = 0.002). Approach was not a significant factor for 1-year HOOS-PS ( p = 0.16) or 1-year UCLA activity ( p = 0.382). Pairwise comparisons showed no significant difference in 1-year HOOS pain scores between DA and PL approach ( p  > 0.05). AL/DL approach had lower (worse) pain scores than DA or PL approaches with differences in adjusted median score of 3.47 and 2.43, respectively ( p  < 0.05).

Conclusions:

Patients receiving the AL/DL approach had a small statistical difference in pain scores at 1 year, but no clinically meaningful differences in pain, activity, or function exist at 1-year postoperative.
Overview of Ultrasound Imaging Applications in Dermatology
Authors: Almuhanna Nouf , Wortsman Ximena , Wohlmuth-Wieser Iris , Kinoshita-Ise Misaki , Alhusayen Raed
Published: March 2021

Complete visualization of lesions is critical for the accurate diagnosis and management of dermatological diseases. Currently, the most readily available technologies used by dermatologists include dermoscopy and photography. Nevertheless, ultrasound has emerged as a useful non-invasive modality in dermatology, which can be added to the clinical examination supporting an early and more accurate diagnosis. Moreover, there are significant technological advances in recent years, such as the development of handheld devices and ultra-high frequency probes that have expanded the integration of ultrasound into daily dermatology practice. In this article, we reviewed the most common applications of ultrasound in the field of dermatology.
Robotic-Assisted Complex Pulmonary Resection: Sleeve Lobectomy for Cancer
Authors: Watkins Ammara A. , Quadri Syed M. , Servais Elliot L.
Published: March 2021

The use of robotic assistance for complex pulmonary resections such as segmentectomy and sleeve lobectomy has steadily increased in recent years. These operations are technically challenging as they require fine dissection and suturing, which is often difficult to perform using traditional minimally invasive techniques. Robotic surgery is well-suited for complex pulmonary surgery given its specific advantages related to superior optics and precise tissue manipulation and dissection. Herein we describe our technique for robotic-assisted complex pulmonary surgery with a specific focus on right upper sleeve lobectomy for cancer, including associated video case demonstration. The principles discussed are generalizable to other complex lung and tracheobronchial operations and highlight the benefits of the robotic platform.
Transxiphoid Revascularization of the Anterior Descending Coronary Artery with the Left Mammary Artery
Authors: Kiser Andy C. , Nifong L. Wiley , Elbeery Joseph R. , Caranasos Thomas G.
Published: March 2021

Revascularization of the coronary arteries, via open sternotomy and on cardiopulmonary bypass, remains the most common cardiac surgical procedure in the United States. Patients, and cardiologists, seek an alternative to dividing the sternum while reaping the advantages of left internal mammary artery (LIMA) revascularization of the diseased left anterior descending (LAD) coronary artery. We describe a strictly transxiphoid mammary artery liberation with anastomosis to the anterior descending (TRAX CABG) without sternal division. Of the 26 patients who underwent attempted TRAX CABG, 18 had nonsternotomy LIMA-to-LAD revascularization with completion angiogram to document bypass patency. TRAX CABG offers surgeons a minimally invasive alternative to trans-sternal LIMA-to-LAD in select patients. Conversion to traditional sternotomy has limited unanticipated morbidity and completion angiogram confirms procedural success.