bluuebunny/crossref_metadata_2025 huggingface dataset:
Follow that cell: leukocyte migration in L-plastin mutant zebrafish
Authors: Linehan J.B. , Zepeda J.L. , Mitchell T.A. , LeClair E.E.
Published: February 2022

Actin assemblies are important in motile cells such as leukocytes which form dynamic plasma membrane extensions or podia. L-plastin (LCP1) is a leukocyte-specific calcium-dependent actin-bundling protein that, in mammals, is known to affect immune cell migration. Previously, we generated CRISPR/Cas9 engineered zebrafish lacking L-plastin (lcp1-/-) and reported that they had reduced survival to adulthood, suggesting that lack of L-plastin might negatively affect the immune system. To test this hypothesis, we examined the distribution and migration of neutrophils and macrophages in the transparent tail of early zebrafish larvae using cell-specific markers and an established wound-migration assay. Knockout larvae were similar to their heterozygous siblings in having equal body sizes and comparable numbers of neutrophils in caudal hematopoietic tissue at two days post-fertilization, indicating no gross defect in neutrophil production or developmental migration. When stimulated by a tail wound, all genotypes of neutrophils were equally migratory in a two-hour window. However for macrophages we observed both migration defects and morphological differences. L-plastin knockout macrophages still homed to wounds but were slower, less directional and had a star-like morphology with many leading and trailing projections. In contrast, wild type macrophages were faster, more directional, and had a more streamlined, slug-like morphology. Overall, these findings show that in larval zebrafish L-plastin knockout primarily affects the macrophage response with possible consequences for organismal immunity. Consistent with our observations, we propose a model in which cytoplasmic L-plastin negatively regulates macrophage integrin adhesion by holding these transmembrane heterodimers in a ‘clasped’, inactive form and is a necessary part of establishing macrophage polarity during chemokine-induced motility.
Leukemia-intrinsic determinants of CAR-T response revealed by iterativein vivogenome-wide CRISPR screening
Authors: Ramos Azucena , Koch Catherine E. , Liu Yunpeng , Hellinger Riley D. , Kyung Taeyoon , Abbott Keene L. , Fröse Julia , Goulet Daniel , Gordon Khloe S. , Larson Rebecca C , Doench John G. , Regev Aviv , Vander Heiden Matthew G. , Maus Marcela V. , Birnbaum Michael E. , Hemann Michael T.
Published: February 2022

CAR-T therapy is a promising new treatment modality for B-cell malignancies. However, the majority of patients inevitably go on to experience disease relapse through largely unknown means. To investigate leukemia-intrinsic CAR-T resistance mechanisms, we performed genome-wide CRISPR-Cas9 loss-of-function screens in an immunocompetent murine model of B-cell acute lymphoblastic leukemia (B-ALL) utilizing a novel, modular guide RNA library. We identified IFNγ/JAK/STAT signaling and components of antigen processing and presentation pathway as key mediators of resistance to CAR-T therapyin vivo, but notin vitro. Transcriptional characterization of this model demonstrated an upregulation of these pathways in CAR-T treated relapsed tumors, and examination of data from CAR-T treated patients with B-ALL revealed an association between poor outcomes and increased expression of JAK/STAT/MHC-I in leukemia cells. Overall, our data identify an unexpected mechanism of resistance to CAR-T therapy in which tumor cell interaction with CAR-T cellsin vivoinduces expression of an adaptive T-cell resistance program in tumor cells.
Factors that affected the qualification of standardized residency training of internal medicine: a prospective longitudinal study
Authors: Sun Yunjuan , Xu Jialiang , Hu Limei , Qi Jiajun
Published: February 2022

Introduction

Since the standardized residency training (SRT) was launched in 2014, there were very few data on evaluation of the factors that could influence the residents’ competency in China.

Methods

All residents who started their SRT programme from September 2015 to September 2018 were enrolled in this study. During the following years, they finished the programme and took examinations. The demographic information and exam scores of each subject were collected and analyzed.

Results

We found that the qualification rates of SRT programme differed significantly annually. Age, gender, the highest medical education degree, residents from different places, training duration and years of medical school study were also different significantly year by year. According to the scores of examinations, residents were divided into two groups: the qualified group and the non-qualified group. Age, the highest medical education degree, residents from different places, training duration, years of medical school study and prior medical work experience differed significantly between the two groups. Multivariate Logistic regression analysis showed the residents from different places and the training duration were factors that affected the qualification rate of SRT programme independently (P = 0.000 and 0.005, respectively).

Discussion

The “homogeneity” of SRT had been achieved regardless of the individual discrepancy, while the resident from different places and the training duration were obstacles we need to overcome further. Therefore, we should further advance the process of the transition from “Unit Persons” to “Society Persons”. And extending training duration will facilitate their qualification and be benefit to improve their competency.
A two-gene strategy increases the iron and zinc concentration of wheat flour and improves mineral bioaccesibility for human nutrition
Authors: Harrington Sophie A , Connorton James M , Nyangoma Natasha I M , McNelly Rose , Morgan Yvie M L , Aslam Mohamad F , Sharp Paul A , Johnson Alexander A T , Uauy Cristobal , Balk Janneke
Published: February 2022

Dietary deficiencies of iron and zinc cause human malnutrition globally, which can be mitigated by biofortified staple crops. Conventional breeding approaches to increase grain mineral concentrations in wheat (Triticum aestivum L.) have had only limited success so far due to relatively low genetic variation. Here we demonstrate that a transgenic approach combining endosperm-specific expression of the wheat vacuolar iron transporter gene TaVIT2-D with constitutive expression of the rice nicotianamine synthase gene OsNAS2 has the potential to dramatically improve mineral micronutrient intake from wheat products. In two distinct bread wheat cultivars, we show that the VIT-NAS construct led to a two-fold increase in zinc to ∼50 µg g-1 in wholemeal flour and a two-fold increase in both zinc and iron in hand-milled white flour. In highly pure, roller-milled white flour, the concentration of iron was enhanced three-fold to ∼25 µg g-1. A greater than three-fold increase in the level of the natural plant metal chelator nicotianamine in the grain of VIT-NAS lines was associated with improved iron and zinc bioaccessibility in white flour. The growth of VIT-NAS plants in the greenhouse was indistinguishable from untransformed controls. We conclude that the effects of each gene cassette are additive in altering the total concentration and distribution of iron and zinc in wheat grains. This demonstrates the potential of a transgenic approach to enhance the nutritional quality of wheat well beyond what is possible by breeding approaches in order to alleviate dietary mineral deficiencies.
nPoRe:n-Polymer Realigner for improved pileup variant calling
Authors: Dunn Tim , Blaauw David , Das Reetuparna , Narayanasamy Satish
Published: February 2022

Despite recent improvements in nanopore basecalling accuracy, germline variant calling of small insertions and deletions (INDELs) remains poor. Although precision and recall for single nucleotide polymorphisms (SNPs) now regularly exceeds 99.5%, INDEL recall at relatively high coverages (85×) remains below 80% for standard R9.4.1 flow cells [22, 23, 31]. Current nanopore variant callers work in two stages: an efficient pileup-based method identifies candidates of interest, and then a more expensive full-alignment model provides the final variant calls. Most false negative INDELs are lost during the first (pileup-based) step, particularly in low-complexity repeated regions. We show that read phasing and realignment can recover a significant portion of INDELs lost during this stage. In particular, we extend Needleman-Wunsch affine gap alignment by introducing new gap penalties for more accurately aligning repeatedn-polymer sequences such as homopolymers (n= 1) and tandem repeats (2 ≤n≤ 6). On our dataset with 60.6× coverage, haplotype phasing improves INDEL recall in all evaluated high confidence regions from 63.76% to 70.66% and then nPoRe realignment improves it further to 73.04%, with no loss of precision.
IKK2/NFkB signaling controls lung resident CD8 T cell memory during influenza infection
Authors: Pritzl Curtis J. , Luera Dezzarae , Knudson Karin M. , Quaney Michael J. , Daniels Mark A. , Teixeiro Emma
Published: February 2022

CD8 tissue resident memory (TRM) cells are especially suited to control pathogen spread at mucosal sites. However, their maintenance in lung is limited. Here, we found that enhancing NFkB signaling in T cells once memory to influenza is established increased pro-survival Bcl-2 and CD122 levels boosting lung CD8 TRM maintenance. By contrast, enhancing NFkB signals during the contraction phase of the response led to a defect in TRM differentiation without impairing recirculating memory subsets. Specifically, inducible activation of NFkB via constitutive active IKK2 or tumor necrosis factor (TNF) interfered with tumor growth factor beta (TGFβ) signaling resulting in defects of lung CD8 TRM imprinting molecules CD69, CD103, Runx3 and Eomes. Conversely, inhibiting NFkB signals not only recovered but improved the transcriptional signature and generation of lung CD8 TRM. Thus, NFkB signaling is a critical regulator of tissue resident memory, whose levels can be tuned at specific times during infection to boost lung CD8 TRM.
Kinesin-1 promotes centrosome clustering and nuclear migration in theDrosophilaoocyte
Authors: Loh Maëlys , Bernard Fred , Guichet Antoine
Published: February 2022

Accurate positioning of the nucleus is essential. Microtubules and their associated motors are important players in this process. Although nuclear migration inDrosophilaoocytes is controlled by microtubule, a role for microtubule-associated molecular motors in nuclear positioning has yet to be reported. We characterize novel landmarks that allow a precise description of the pre-migratory stages. Using these newly defined stages, we report that, prior to migration, the nucleus moves from the oocyte anterior side toward the center and concomitantly the centrosomes cluster at the posterior of the nucleus. In absence of Kinesin-1, centrosome clustering is impaired and the nucleus fails to position and migrate properly. The maintenance of a high level of Polo-kinase at centrosomes prevents centrosome clustering and impairs nuclear positioning. In absence of Kinesin-1, SPD2 an essential component of the pericentriolar material is increased at the centrosomes, suggesting that Kinesin-1 associated defects result from a failure to reduce centrosome activity. Consistently, depleting centrosomes rescues the nuclear migration defects induced by Kinesin-1 inactivation. Our results suggest that Kinesin-1 controls nuclear migration in the oocyte by modulating centrosome activity.

Summary statement

In this study, we identified a crucial role of Kinesin-1 in centrosome clustering required for nuclear positioning and migration in theDrosophilaoocyte.
Excited-state dynamics of the all-trans protonated retinal Schiff base in CRABPII-based rhodopsin mimics
Authors: Li Gaoshang , Hu Yongnan , Pei Sizhu , Meng Jiajia , Wang Jiayu , Wang Ju , Yue Shuai , Wang Zhuan , Wang Shufeng , Liu Xinfeng , Weng Yuxiang , Peng Xubiao , Zhao Qing
Published: February 2022

The rhodopsin mimic is a chemically synthetized complex with the retinyl Schiff base (RSB) formed between protein and the retinal chromophore, which can mimic the natural rhodopsin-like protein. The artificial rhodopsin mimic is more stable and designable than the natural protein and hence has wider uses in photon detection devices. The mimic structure RSB, like the case in the actual rhodopsin-like protein, undergoes isomerization and protonation throughout the photoreaction process. As a result, understanding the dynamics of the RSB in the photoreaction process is critical. In this study, the transient absorption spectra (TAS) of three mutants of the cellular retinoic acid-binding protein II (CRABPII)-based rhodopsin mimic at PH = 3 were recorded, from which the related excited-state dynamics of the all-trans protonated RSB (AT-PRSB) were investigated. The transient fluorescence spectra (TFS) measurements are used to validate some of the dynamic features. We find that the excited-state dynamics of AT-PRSB in three mutants share a similar pattern that differs significantly from the dynamics of 15-cis PRSB (15C-PRSB) of the rhodopsin mimic in neutral solution. By comparing the dynamics across the three mutants, we discovered that the aromatic residues near the β-ionone ring structure of the retinal may help stabilize the AT-PRSB and hence slow down its isomerization rate. Furthermore, from the three mutants, we find one protein with near-infrared fluorescence emission up to 688 nm, leading to further possible applications in sensing or bioimaging.
A natural broad-spectrum inhibitor of enveloped virus entry, effective against SARS-CoV-2 and Influenza A Virus in preclinical animal models
Authors: Narayan Rohan , Sharma Mansi , Yadav Rajesh , Biji Abhijith , Khatun Oyahida , Rajmani Raju , Sharma Pallavi Raj , Jeyasankar Sharumathi , Rani Priya , Rao C. Durga , Satchidanandanam Vijaya , Das Saumitra , Agarwal Rachit , Tripathi Shashank
Published: February 2022

The COVID-19 pandemic has highlighted the need for novel antivirals for pandemic management and preparedness. Targeting host processes that are co-opted by viruses is an attractive strategy for developing antivirals with a high resistance barrier. Picolinic acid (PA) is a byproduct of tryptophan metabolism, endogenously produced in humans and other mammals. Here we report broad-spectrum antiviral effects of PA against enveloped viruses, including Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), Influenza A virus (IAV), Flaviviruses, Herpes Simplex Virus, and Human Parainfluenza Virus. We further demonstrate using animal models that PA is effective against SARS-CoV-2 and IAV, especially as an oral prophylactic. The mode of action studies revealed that PA inhibits viral entry of enveloped viruses, primarily by interfering with viral-cellular membrane fusion, inhibiting virus-mediated syncytia formation, and dysregulating cellular endocytosis. Overall, our data establish PA as a broad-spectrum antiviral agent, with promising preclinical efficacy against pandemic viruses SARS-CoV-2 and IAV.
Timeliness of reporting of SARS-CoV-2 seroprevalence results and their utility for infectious disease surveillance
Authors: Donnici Claire , Ilincic Natasha , Cao Christian , Zhang Caseng , Deveaux Gabriel , Clifton David A. , Buckeridge David , Bobrovitz Niklas , Arora Rahul K.
Published: February 2022

Seroprevalence studies have been used throughout the COVID-19 pandemic to monitor infection and immunity. These studies are often reported in peer-reviewed journals, but the academic writing and publishing process can delay reporting and thereby public health action. Seroprevalence estimates have been reported faster in preprints and media, but with concerns about data quality. We aimed to (i) describe the timeliness of SARS-CoV-2 serosurveillance reporting by publication venue and study characteristics and (ii) identify relationships between timeliness, data validity, and representativeness to guide recommendations for serosurveillance efforts.

We included seroprevalence studies published between January 1, 2020 and December 31, 2021 from the ongoing SeroTracker living systematic review. For each study, we calculated timeliness as the time elapsed between the end of sampling and the first public report. We evaluated data validity based on serological test performance and correction for sampling error, and representativeness based on use of a representative sample frame and adequate sample coverages. We examined how timeliness varied with study characteristics, representativeness, and data validity using univariate and multivariate Cox regression.

We analyzed 1,844 studies. Median time to publication was 154 days (IQR 64-255), varying by publication venue (journal articles: 212 days, preprints: 101 days, institutional reports: 18 days, and media: 12 days). Multivariate analysis confirmed the relationship between timeliness and publication venue and showed that general population studies were published faster than special population or health care worker studies; there was no relationship between timeliness and study geographic scope, geographic region, representativeness, or serological test performance.

Seroprevalence studies in peer-reviewed articles and preprints are published slowly, highlighting the limitations of using the academic literature to report seroprevalence during a health crisis. More timely reporting of seroprevalence estimates can improve their usefulness for surveillance, enabling more effective responses during health emergencies.
Effect of mHealth interventions on psychological issues experienced by women diagnosed with breast cancer receiving chemotherapy: A systematic review and meta-analysis
Authors: Akingbade Oluwadamilare , Nguyen Khanh Thi , Chow Ka Ming
Published: February 2022

Background

A range of psychological issues often accompany breast cancer chemotherapy. Owing to their ubiquity, mobile phones have been used to deliver supportive interventions that address these issues. However, we currently lack sufficient evidence to guide the design of such interventions.

Aim

To analyse and synthesise available evidence on the effectiveness of mobile-phone-based (mHealth) interventions in alleviating the psychological issues experienced by women receiving chemotherapy for breast cancer.

Methods

A systematic literature search was conducted from 14 relevant databases. Revman 5.4 was used to pool the quantitative results from comparable studies for statistical meta-analysis. For clinically heterogeneous studies where statistical pooling of results was not possible, a narrative summary was used to present the findings.

Results

The review included ten published studies which covered 1,548 patients. The meta-analysis results indicated a significant improvement in the quality of life (standardised mean difference [SMD] = 0.32, 95% confidence interval [CI] [0.07, 0.58], p = .01, I2 = 17%). No significant effects were found for anxiety (SMD = -0.01, 95% CI [-0.26, 0.25], p = 0.96, I2 = 53%) and depression (SMD = 0.02, 95% CI [-0.17, 0.20], p = .87, I2 = 0%). Individual studies suggest reduced symptom prevalence (p = .033, d =.27), symptom distress (p = .004, d = .004), symptom interference (p = .02, d = .51), supportive care needs (p < .05, d = 2.43); improved self-efficacy (p = .03, d = 0.53), self-esteem (p <.001, d = 0.87) and emotional functioning (p = .008, d = .30). The methodological quality ranged from low to moderate.

Conclusion

mHealth interventions might be helpful in addressing certain psychological issues experienced by this population, although the evidence is still being gathered and not yet conclusive. More rigorous trials are hereby warranted to confirm the suitable duration while addressing the methodological flaws found in previous studies

PROSPERO registration number

CRD42021224307
An ACE2-blocking antibody confers broad neutralization and protection against Omicron and other SARS-CoV-2 variants
Authors: Du Wenjuan , Hurdiss Daniel L. , Drabek Dubravka , Mykytyn Anna Z. , Kaiser Franziska K. , González-Hernandez Mariana , Muñoz-Santos Diego , Lamers Mart M. , van Haperen Rien , Li Wentao , Drulyte Ieva , Wang Chunyan , Sola Isabel , Armando Federico , Beythien Georg , Ciurkiewicz Malgorzata , Baumgärtner Wolfgang , Guilfoyle Kate , Smits Tony , van der Lee Joline , van Kuppeveld Frank J.M. , van Amerongen Geert , Haagmans Bart L. , Enjuanes Luis , Osterhaus Albert D.M.E. , Grosveld Frank , Bosch Berend-Jan
Published: February 2022

The ongoing evolution of SARS-CoV-2 has resulted in the emergence of Omicron, which displays striking immune escape potential. Many of its mutations localize to the spike protein ACE2 receptor-binding domain, annulling the neutralizing activity of most therapeutic monoclonal antibodies. Here we describe a receptor-blocking human monoclonal antibody, 87G7, that retains ultrapotent neutralization against SARS-CoV-2 variants including the Alpha, Beta, Gamma, Delta and Omicron (BA.1/BA.2) Variants-of-Concern (VOCs). Structural analysis reveals that 87G7 targets a patch of hydrophobic residues in the ACE2-binding site that are highly conserved in SARS-CoV-2 variants, explaining its broad neutralization capacity. 87G7 protects mice and/or hamsters against challenge with all current SARS-CoV-2 VOCs. Our findings may aid the development of sustainable antibody-based strategies against COVID-19 that are more resilient to SARS-CoV-2 antigenic diversity.

One sentence summary

A human monoclonal antibody confers broad neutralization and protection against Omicron and other SARS-CoV-2 variants
CipA mediates complement resistance of Acinetobacter baumannii by formation of a Factor I-dependent quadripartite assemblage
Authors: Ries Julia I. , Heß Marie , Nouri Noura , Wichelhaus Thomas A. , Göttig Stephan , Falcone Franco H. , Kraiczy Peter
Published: February 2022

Multidrug-resistant Acinetobacter baumannii is known to be one of the leading pathogens that cause severe nosocomial infections. To overcome eradication by the innate immune system during infection, A. baumannii developed a number of immune evasion strategies. Previously, we identified CipA as a plasminogen-binding and complement-inhibitory protein. Here we show that CipA strongly inhibits all three complement activation pathways and interacts with key complement components C3, C3b, C4b, C5, Factor B, Factor D, and in particular Factor I. CipA also targets function of the C5 convertase as cleavage of C5 was impaired. Systematic screening of CipA variants identified two separate binding sites for C3b and a Factor I-interacting domain located at the C-terminus. Structure predictions using AlphaFold2 and binding analyses employing CipA variants lacking Factor I-binding capability confirmed that the orientation of the C-terminal domain is essential for the interaction with Factor I. Hence, our analyses point to a novel, Factor I-dependent mechanisms of complement inactivation mediated by CipA of A. baumannii. Recrutiment of Factor I by CipA initiates the assembly of a quadripartite complex following binding of either Factor H or C4b-binding protein to degrade C3b and C4b, respectively. Loss of Factor I binding in a CipA-deficient strain, or a strain producing a CipA variant lacking Factor I-binding capability, correlated with a higher susceptibility to human serum, indicating that recruitment of Factor I enables A. baumannii to resist complement-mediated killing.

Significance Statement

The Gram-negative bacterium Acinetobacter baumannii causes severe nosocomial infections and has developed various immune evasion strategies to overcome complement. The mechanisms how Acinetobacter baumannii successfully circumvents complement-mediated bacteriolysis are still poorly understood. Here, we show that the plasminogen-binding and complement inhibitory protein CipA terminates all three complement activation pathways. We describe a novel mechanism by which CipA cleaves the key complement components C3b and C4b in the presence of Factor H and C4b-binding protein by formation of a novel Factor I-dependent quadripartite complex. CipA, which has recently been successfully used for vaccination approaches, might represent an attractive target for the development of novel therapeutic interventions to block disorders with excessive hyperinflammatory complement activation.
Distinct physiological responses ofCoccolithus braarudiilife cycle phases to light intensity and nutrient availability
Authors: Langer Gerald , Jie Vun Wen , Kottmeier Dorothee , Flori Serena , Sturm Daniela , de Vries Joost , Harper Glenn M. , Brownlee Colin , Wheeler Glen
Published: February 2022

Coccolithophores feature a haplo-diplontic life cycle comprised of diploid cells producing heterococcoliths and haploid cells producing morphologically different holococcoliths. These life cycle phases of each species appear to have distinct spatial and temporal distributions in the oceans, with the heavily-calcified heterococcolithophores (HET) often more prevalent in winter and at greater depths, whilst the lightly-calcified holococcolithophores (HOL) are more abundant in summer and in shallower waters. The haplo-diplontic life cycle may therefore allow coccolithophores to expand their ecological niche, switching between life cycle phases to exploit conditions that are more favourable. However, coccolithophore life cycles remain poorly understood and fundamental information on the physiological differences between life cycle phases is required if we are to better understand the ecophysiology of coccolithophores. In this study, we have examined the physiology of HET and HOL phases of the coccolithophoreCoccolithus braarudiiin response to changes in light and nutrient availability. We found that the HOL phase was more tolerant to high light than the HET phase, which exhibited defects in calcification at high irradiances. The HET phase exhibited defects in coccolith formation under both nitrate (N) and phosphate (P) limitation, whilst no defects in calcification were detected in the HOL phase. The HOL phase grew to a higher cell density under P-limitation than N-limitation, whereas no difference was observed in the maximum cell density reached by the HET phase at these nutrient concentrations. HET cells grown under a light:dark cycle divided primarily in the dark and early part of the light phase, whereas HOL cells continued to divide throughout the 24 h period. The physiological differences may contribute to the distinct biogeographical distributions observed between life cycle phases, with the HOL phase potentially better adapted to high light, low nutrient regimes, such as those found in seasonally stratified surface waters.

Highlights

Coccolithus braarudiilife cycle phases exhibit different physiological responses.

The heavily-calcified heterococcolithophores (HET) life cycle phase is more sensitive to high light.

The lightly-calcified holococcolithophores (HOL) life cycle phase may be better suited to growth under low phosphate availability.
Low Density Lipoprotein Receptor-Related Protein 1 (LRP1) as an auxiliary host factor for RNA viruses including SARS-CoV-2
Authors: Devignot Stephanie , Sha Tim Wai , Burkard Thomas R. , Schmerer Patrick , Hagelkruys Astrid , Mirazimi Ali , Elling Ulrich , Penninger Josef M. , Weber Friedemann
Published: February 2022

Viruses with an RNA genome are often the cause of zoonotic infections. In order to identify novel pro-viral host cell factors, we screened a haploid insertion-mutagenized mouse embryonic cell library for clones that rendered them resistant to the zoonotic Rift Valley fever virus (RVFV; familyPhleboviridae, orderBunyavirales). This screen returned the Low Density Lipoprotein Receptor-Related protein 1 (LRP1, or CD91) as top hit, a 600 kDa plasma membrane protein known to be involved in a wide variety of cell activities. Inactivation of LRP1 expression in human cells reduced RVFV RNA levels already at the attachment and entry stages of infection. Moreover, the role of LRP1 in promoting RVFV infection was dependent on physiological levels of cholesterol and on endocytosis. In the highly LRP1-positive human cell line HuH-7, LRP1 also promoted the early infection stages of Sandfly fever Sicilian virus (SFSV; familyPhleboviridae, orderBunyavirales), La Crosse virus (LACV; familyPeribunyaviridae, orderBunyavirales), had a minor effect on RNA levels during the late infection stages by vesicular stomatitis virus (VSV; familyRhabdoviridae, orderMononegavirales), whereas infection by Encephalomyocarditis virus (EMCV, familyPicornaviridae) was entirely LRP1-independent. Moreover, siRNA experoments in human Calu-3 cells demonstrated that also SARS-CoV-2 infection benefitted from LRP1. Thus, we identified LRP1 as a host factor that supports infection by a spectrum of RNA viruses.
A novel fluorescent multi-domain protein construct reveals the individual steps of the unfoldase action of Hsp70
Authors: Tiwari Satyam , Fauvet Bruno , Assenza Salvatore , De los Rios Paolo , Goloubinoff Pierre
Published: February 2022

A detailed understanding of the mechanism by which Hsp70 chaperones protect cells against protein aggregation is hampered by the detailed characterization of the aggregates, which are typically heterogeneous. To tackle this problem, we designed here a reporter chaperone substrate, MLucV, composed of a stress-labile luciferase core, flanked by stress-resistant fluorescent mTFP and Venus domains, which upon denaturation formed a discrete stable population of small aggregates. Combining Förster Resonance Energy Transfer and enzymatic activity measurements provided unprecedent details on MLucV states, including native, aggregated, unfolded and chaperone-bound conformations. Using MLucV, we probed the various steps undertaken by bacterial Hsp70 to convert stable discrete aggregates into native proteins. The mechanism first involved an ATP-fuelled disaggregation and unfolding step of the stable pre-aggregated substrate, with a consequent stretching of MLucV beyond simply-unfolded conformations, followed, upon release, by native refolding. Furthermore, the ATP-fuelled unfolding action of Hsp70 on MLucV aggregates could accumulate native MLucV species under elevated denaturing temperatures, highly adverse to the native state. These results unambiguously excluded binding and preventing aggregation from the non-equilibirum mechanism by which Hsp70 converts stable aggregates into metastable native proteins.
Benchmarking Peptide Structure Prediction with AlphaFold2
Authors: Gulsevin Alican , Meiler Jens
Published: February 2022

AlphaFold2 (AF2) is a computational tool developed for the determination of protein structures with high accuracy. AF2 has been used for the modeling of many soluble and membrane proteins, but its performance in modeling peptide structures has not been systematically investigated so far. We benchmarked the accuracy of AF2 in predicting peptide structures between 16 – 60 amino acids using experimentally-determined peptide structures as reference. Our results show that while AF2 can predict the structures of certain peptide scaffolds with RMSD values below 3 Å, it is less successful in predicting the structures of peptides that have kinks, turns, or have extended flexible regions. Further, AF2 had several shortcomings in predicting rotamer recoveries, disulfide bonds, and the lowest RMSD structures based on pLDDT values. In summary, AF2 can be a powerful tool to determine peptide structures, but additional steps may be necessary to analyze and validate the results.
How drought affects range and variability of environmental conditions in subtropical South African estuaries
Authors: Scharler UM , Bownes SJ , Jerling H
Published: February 2022

Globally estuaries are under increasing pressure from human development impacts as well as the growing effects of climate change that is already, and increasingly so, causing major changes in events such as droughts. Although droughts are regular occurrences and are projected to become progressively more significant in many parts of the world, their potential impacts on estuaries requires better understanding and quantification. This study aims to quantify environmental and phytoplankton parameter changes in two contrasting subtropical estuary types in South Africa; the temporarily closed uMdloti Estuary and the predominantly open to the sea uMlalazi Estuary during a hydrological drought event and subsequent non-drought period. Drought caused lower salinities, almost exclusively freshwater, throughout the temporarily closed estuarine type uMdloti. The marine-estuarine salinity environment of the predominantly open uMlalazi during drought expanded to include lower salinities in the non-drought period. Dissolved oxygen levels were more variable during drought conditions including periods of hypoxia, but more stable at elevated levels in both estuaries during the non- drought period. Temperature measurements included higher values during drought, especially in the dry season. Chl-a concentrations were overall higher and more variable during drought in uMdloti, with periods of bloom formation as well as decay. Drought-induced conditions can span several generations for estuarine and estuarine associated organisms. The results from the study provide quantitative support for the hypothesis that extended periods of drought conditions lead to a decrease in niche availability to estuarine organisms in a range of estuary types.
In situ architecture of human kinetochore-microtubule interface visualized by cryo-electron tomography
Authors: Zhao Wei , Jensen Grant J.
Published: February 2022

Faithful segregation of chromosomes during mitosis relies on a carefully coordinated and intricate interplay between the centromere, kinetochore, and spindle microtubules. Despite its importance, the architecture of this interface remains elusive. Here we used in situ cryo-electron tomography to visualize the native architecture of the kinetochore-microtubule interface in human U2OS cells at different stages of mitosis. We find that the centromere forms a pocket-like structure around kinetochore microtubules. Two morphologically distinct fibrillar densities form end-on and side-on connections to the plus-ends of microtubules within this centromeric pocket. Our data suggest a dynamic kinetochore-microtubule interface with multiple interactions between outer kinetochore components and spindle microtubules.
Molecular mechanisms of spontaneous curvature and softening in complex lipid bilayer mixtures
Authors: Lessen Henry J. , Sapp Kayla C. , Beaven Andrew H. , Ashkar Rana , Sodt Alexander J.
Published: February 2022

Membrane reshaping is an essential biological process. The chemical composition of lipid membranes determines their mechanical properties, and thus the energetics of their shape. Hundreds of distinct lipid species make up native bilayers, and this diversity complicates efforts to uncover what compositional factors drive membrane stability in cells. Simplifying assumptions, therefore, are used to generate quantitative predictions of bilayer dynamics based on lipid composition. One assumption commonly used is that “per lipid” mechanical properties are both additive and constant — that they are an intrinsic property of lipids independent of the surrounding composition. Related to this, is the assumption that lipid bulkiness, or “shape” determines its curvature preference, independently of context. In this study, all-atom molecular dynamics simulations on three separate multi-lipid systems were used to explicitly test these assumptions, applying methodology recently developed to isolate properties of single lipids or nanometer-scale patches of lipids. The curvature preference of populations of lipid conformations were inferred from their redistribution on a dynamically fluctuating bilayer. Representative populations were extracted by both structural similarity and semi-automated hidden Markov model analysis. The curvature preferences of lipid dimers were then determined and compared to an additive model that combines the monomer curvature preference of both the individual lipids. In all three systems, we identified conformational subpopulations of lipid dimers that showed non-additive curvature preference, in each case mediated by a special chemical interaction (e.g., hydrogen bonding). Our study highlights the importance of specific chemical interactions between lipids in multicomponent bilayers and the impact of interactions on bilayer stiffness. We identify two mechanisms of bilayer softening: Diffusional softening, which is driven by the dynamic coupling between lipid distributions and membrane undulations, and conformational softening, which is driven by the inter-conversion between distinct dimeric conformations.
Hyperactivity of indirect pathway-projecting spiny projection neurons drives compulsive behavior
Authors: Piantadosi Sean C , Manning Elizabeth E , Chamberlain Brittany L , Hyde James , LaPalombara Zoe , Bannon Nicholas M , Pierson Jamie L , Namboodiri Vijay MK , Ahmari Susanne E
Published: February 2022

Compulsive behaviors are a hallmark symptom of obsessive compulsive disorder (OCD). Striatal hyperactivity has been linked to compulsive behavior generation in correlative studies in humans and causal studies in rodents. However, the contribution of the two distinct striatal output populations to the generation and treatment of compulsive behavior is unknown. These populations of direct and indirect pathway-projecting spiny projection neurons (SPNs) have classically been thought to promote or suppress actions, respectively, leading to a long-held hypothesis that increased output of direct relative to indirect pathway promotes compulsive behavior. Contrary to this hypothesis, here we find that indirect pathway hyperactivity drives compulsive grooming in the Sapap3-knockout mouse model of OCD-relevant behavior. Furthermore, we show that suppression of indirect pathway activity using optogenetics or treatment with the first-line OCD pharmacotherapy fluoxetine is associated with reduced compulsive behavior. Together, these findings highlight the striatal indirect pathway as a potential new treatment target for compulsive behavior.
The empirical relationship between contractor success and project innovation
Authors: Langston Craig
Published: February 2022

Purpose

Innovation during project delivery is contested space. The aim in this research is to empirically explore the theory of this contested space and how project implementation can be optimized by the contractor to deliver better outcomes. It is hypothesized that project innovation has a proportional and measurable relationship to contractor success.

Design/methodology/approach

Based on a novel conceptual framework, this research applies a case study methodology to analyse 31 construction projects undertaken by a single Australian middle-tier contractor. Benefits from innovation are not often equitably shared. There are risks and rewards. The project innovation zone is defined as a combination of three key performance indicators – efficacy, efficiency and margin – merged into a single index that most likely shows evidence of “working smarter”.

Findings

Client–contractor project innovation (c2pi) is demonstrated to be strongly correlated with head contractor success (HCS), yielding an r2 value of 71%. Innovative projects mostly show positive change in efficacy, efficiency and margin when comparing “planned” and “actual” outcomes. Across the cases studied, 35% demonstrated likely evidence of innovative delivery and 52% demonstrated evidence of success from the construction contractor's perspective.

Originality/value

These findings verify that, within the studied sample, the pursuit of innovation leads to projects that are likely to also have greater success for the head contractor, evidenced by the mix of five critical success factors: finishing on schedule, making profit, and having less defects, less accidents and higher quality workmanship. These outcomes arguably also apply to sub-contractors, where the head contractor assumes the role of “client”.
How do Chinese SMEs enhance technological innovation capability? From the perspective of innovation ecosystem
Authors: Song Yue
Published: February 2022

Purpose

The purpose of this study is to investigate the influence mechanisms of multi-level ecological participants on technological innovation capabilities within the focal small and mid-size enterprises' (SME) innovation ecosystem. The author examines the moderating role of the innovation ecological environment.

Design/methodology/approach

With the lenses of innovation ecosystem theory, technological innovation theory and ecological theory, the author constructs and empirically tests a conceptual framework for exploring the effects of the focal SME's connections with universities and research institutions, and the industrial chain and ecosphere on their independent and collaborative innovation capabilities. The innovation ecological environment is employed as a moderating variable in the proposed model. The author issued email questionnaires to managers at innovative SMEs in Shenzhen, Shanghai and Jiangsu provinces. The data were used for multiple regression analyses to test the hypotheses.

Findings

As predicted, the author found that SMEs’ cooperation with universities and research institutions positively affects independent and collaborative innovation capability. The relationships between the industrial chain, the ecosphere and independent and collaborative innovation capabilities are all inverted U-shaped. Additionally, the author demonstrates that the innovation ecological environment positively moderates relationships between the focal SME's ecological participants and these two types of technological innovation capabilities.

Originality/value

The results enrich research on innovation ecosystems and technological innovation capability and provide important managerial implications for Chinese SMEs to enhance their technological innovation capability by constructing and coordinating innovation ecosystems. It also allows China, as well as other developing countries, to cultivate world-class enterprises as an innovative nation.
Lines in the sand: the perceived risks of traveling to a destination and its influence on tourist information seeking behavior
Authors: Oshriyeh Omid , Ghaffari Mohammad , Nematpour Mohammad
Published: February 2022

Purpose

This study is aims to identify and categorize the perceived risks of Chinese tourists (from mainland China) traveling to Tehran. In addition, this study investigates the relationship between these risks tourists’ information seeking behavior.

Design/methodology/approach

This study investigates the relationship between these risks tourists’ information seeking behavior. The research also tries to model the relationship between the explored perceived risks and tourists’ information-seeking behavior. To collect data, a researcher-developed questionnaire containing 24 questions was designed based on a literature review. Before collecting the data, the validity and reliability of the questionnaire were reviewed and confirmed. To do study procedure, one essential question and two hypotheses, including exploratory factor analysis, stepwise regression and independent samplesT-test, are used.

Findings

The results showed that Chinese tourists perceived health, physical, political, cultural, social and economic risks before their trip (with political risk being the most prominent). Also, the results indicate that the tourists have used different ways to collect information about Iran in general and Tehran in particular. Those travelers who perceived a higher risk were more likely to use the information sources that provide them with detailed and accurate information before traveling to Tehran.

Research limitations/implications

This study provides valuable insights for destination managers and tourism marketers to attract Chinese tourists by considering their perceived risks and information-seeking behavior. It should be noted that this study is not without its own limitations. These limitations include (but are not limited to) the timeframe in which the data was collected (prior to the outbreak of COVID-19) and the destination (Tehran, Iran). Therefore, it is advised that future researchers study the perceived risks and information sources in other parts of the world.

Originality/value

The concept of perceived risk was used in Chinese tourists’ behavioral seeking to predict their future behavior following their perceptions. Thus, the findings of this study will be necessary to local governments and other destination organizations when building successful strategies.
Theorizing school leadership as a profession: a qualitative exploration of the work of school leaders
Authors: Stone-Johnson Corrie , Weiner Jennie
Published: February 2022

Purpose

In response to the proliferation of neoliberal reforms and a “new professionalism” (Evetts, 2009, 2011), researchers argue that school leaders, like teachers, have experienced a form of “de-professionalization” (Keddie, 2017) and that the principalship may even be an “emergent profession” (Stone-Johnson and Weiner, 2020). Such framing assumes school leaders are indeed part of a profession. And yet, while research abounds regarding teaching as a profession (Ingersoll and Collins, 2018; Sachs, 2016; Torres and Weiner, 2018), no parallel literature exists about school leaders. Such information is critical to ensure educators receive the appropriate professional development and support (Sachs, 2016) and move the field forward and thus motivated the authors to ask how principals view their work and whether it can be seen as part of a discrete profession.

Design/methodology/approach

The authors utilized an interpretative phenomenological approach (IPA) drawing on qualitative interviews with sixteen elementary school principals in two US states.

Findings

The authors find administration, and specifically the principalship, exists adjacent to, but distinct from, teaching. Additionally, the authors find school leadership is an “emergent” profession, with aspects of the work that indicate leadership is a profession but others that do not.

Originality/value

This study extends early work (Stone-Johnson and Weiner, 2020) on the impact of the COVID-19 pandemic on principals' professionalism to shed light on the larger and more long-standing features of principals' work that support and hinder its development as a profession and the implications of such designation on attracting and retaining school leaders, as well as underscoring that because school leadership and teaching can be considered discrete professions, teachers need not leave their classroom to be true professionals.
Framing intellectual capital for elite athletes
Authors: Aprile Roberto , Nicoliello Mario , Durst Susanne
Published: February 2022

Purpose

This conceptual paper proposes an intellectual capital (IC) framework dedicated to elite athletes (EA) to demonstrate the usefulness of IC on individual persons. Thus, it connects EA with the concept of IC.

Design/methodology/approach

The paper is inspired by the classical IC dimensions (human capital, structural capital and relational capital), which are used to develop the IC framework for EA. An exemplary case study is used to validate the framework.

Findings

It is argued that there is a need to adapt the traditional IC framework for EA. Therefore, this paper proposes a specific IC framework consisting of natural capital, sports capital and media capital.

Research limitations/implications

This paper deals with EA and the sports industry, but should be extended to other sectors where aspects such as image and celebrity represent significant intangible resources.

Practical implications

The proposed IC framework can help EA and their managers to better understand how IC value is created.

Originality/value

This paper extends the IC concept to other fields of application, i.e. EA, and thus individual persons.