bluuebunny/crossref_metadata_2025 huggingface dataset:
Triploidy affects standard and postprandial metabolism in brook charr,Salvelinus fontinalis
Authors: Daigle Nicole J. , Sacobie Charles F.D. , Verhille Christine E. , Benfey Tillmann J.
Published: August 2020

The use of sterile triploids in aquaculture is currently limited because of reduced performance in situations of aerobic stress such as high temperature, hypoxia, and exhaustive exercise. Many studies have therefore attempted to find underlying metabolic differences between triploids and their diploid counterparts to improve triploid rearing protocols. This study investigated the effects of triploidy on postprandial metabolism (and therefore also pre-feeding standard metabolic rate; SMR) by measuring oxygen uptake and total ammonia nitrogen (TAN) excretion at 14-15°C of previously fasted (for eight days) diploid and triploid brook charr,Salvelinus fontinalis, from 48h before to 48h after being fed a single ration of 0.4% body mass. Triploids had significantly lower SMRs and higher postprandial metabolic rates (i.e., specific dynamic action) and net TAN excretion than diploids. While this greater cost of processing a meal may not represent a major diversion of metabolic reserves for triploids, it could affect their growth and survival when simultaneously faced with oxygen-limiting conditions.
Genetic structure of the Coconut Rhinoceros Beetle (Oryctes rhinoceros) population and the incidence of its biocontrol agent (Oryctes rhinoceros nudivirus) in the South Pacific Islands
Authors: Etebari Kayvan , Hereward James , Sailo Apenisa , Ahoafi Emeline M. , Tautua Robert , Tsatsia Helen , Jackson Grahame V , Furlong Michael J.
Published: August 2020

Incursions of the Coconut rhinoceros beetle (CRB),Oryctes rhinoceros, have been detected in several countries of the south west Pacific in recent years, resulting in an expansion of the pest’s geographic range. It has been suggested that this resurgence is related to anO. rhinocerosmitochondrial lineage (previously referred to as the CRB-G “biotype”) that is reported to show reduced susceptibility to the well-established classical biocontrol agent, Oryctes rhinoceros nudivirus (OrNV). We investigatedO. rhinocerospopulation genetics and the OrNV status of adult specimens collected in the Philippines and seven different South Pacific island countries (Fiji, New Caledonia, Papua New Guinea (PNG), Samoa, Solomon Islands, Tonga, and Vanuatu). Based on the presence of single nucleotide polymorphisms (snps) in the mitochondrial Cytochrome C Oxidase subunit I (CoxI) gene, we found three major mitochondrial lineages (CRB-G, a PNG lineage (CRB-PNG) and the South Pacific lineage (CRB-S)) across the region. Haplotype diversity varied considerably between and within countries. TheO. rhinocerospopulation in most countries was monotypic and all individuals tested belonged to a single mitochondrial lineage (Fiji, CRB-S; Tonga, CRB-S; Vanuatu, CRB-PNG; PNG (Kimbe), CRB-PNG; New Caledonia CRB-G; Philippines, CRB-G). However, in Samoa we detected CRB-S and CRB-PNG and in Solomon Islands we detected all three haplotype groups. Genotyping-by-Sequencing (GBS) methods were used to genotype 10,000snps from 230 insects across the Pacific and showed genetic differentiation in theO. rhinocerosnuclear genome among different geographical populations. The GBS data also provided evidence for gene flow and admixture between different haplotypes in Solomon Islands. Therefore, contrary to earlier reports, CRB-G is not solely responsible for damage to the coconut palms reported since the pest was first recorded in Solomon Islands in 2015. We also PCR-screened a fragment of OrNV from 260 insects and detected an extremely high prevalence of viral infection in all three haplotypes in the region. We conclude that the haplotype groups CRB-G, CRB-S, and PNG, do not represent biotypes, subspecies, or cryptic species, but simply represent different invasions ofO. rhinocerosacross the Pacific. This has important implications for management, especially biological control, of Coconut rhinoceros beetle in the region.
The histidine phosphotransfer AHP4 plays a negative role inArabidopsisplant response to drought
Authors: Van Ha Chien , Nguyen Kien Huu , Mostofa Mohammad Golam , Tran Cuong Duy , Watanabe Yasuko , Li Weiqiang , Osakabe Yuriko , Sato Mayuko , Toyooka Kiminori , Tanaka Maho , Seki Motoaki , Burritt David J. , Anderson Cheyenne , Zhang Ru , Phan Tran Lam-Son
Published: August 2020

Cytokinin plays an important role in plant stress responses via a multistep signaling pathway, involving the histidine phosphotransfer proteins (HPs). InArabidopsis thaliana, the AHP2, AHP3 and AHP5 proteins are known to impact drought responses; however, the role of AHP4 in drought adaptation remains undetermined. In the present study, using a loss-of-function approach we showed that AHP4 possesses a negative regulatory role inArabidopsis’s response to drought. This is evidenced by both higher survival rates ofahp4than wild-type (WT) plants under drought conditions, and the down-regulatedAHP4expression in WT during periods of dehydration. Comparative transcriptome analysis ofahp4and WT plants revealed AHP4-mediated expression of several dehydration- and/or abscisic acid (ABA)-responsive genes involved in regulation of various physiological and biochemical processes important for plant drought acclimation. In comparison with WT,ahp4plants showed increased wax crystal accumulation in stems, thicker cuticles in leaves, greater sensitivity to exogenous ABA at germination, narrow stomatal apertures, heightened leaf temperatures during dehydration, and longer root length under osmotic stress. Additionally,ahp4plants showed greater photosynthetic efficiency, lower levels of reactive oxygen species (ROS), reduced electrolyte leakage and lipid peroxidation, and increased anthocyanin contents under drought, when compared with WT. These differences displayed inahp4plants are likely due to up-regulation of genes that encode enzymes involved in ROS-scavenging and non-enzymatic antioxidant metabolism. The role of AHP4 in negative regulation of multiple protective mechanisms associated with drought tolerance could make editing ofAHP4a promising approach for the production of drought-tolerant crop plants.

Significance statement

Loss-of-function analysis of the cytokinin signaling member AHP4 revealed its function inArabidopsisadaptation to drought as a negative regulator, affecting various physiological and biochemical processes by modulating the expression of a large set of genes potentially in a crosstalk with ABA.AHP4and its homologs are promising candidates for gene editing to develop drought-tolerant crop cultivars.
MacaquePose: A novel ‘in the wild’ macaque monkey pose dataset for markerless motion capture
Authors: Labuguen Rollyn , Matsumoto Jumpei , Negrete Salvador , Nishimaru Hiroshi , Nishijo Hisao , Takada Masahiko , Go Yasuhiro , Inoue Ken-ichi , Shibata Tomohiro
Published: August 2020

Video-based markerless motion capture permits quantification of an animal’s pose and motion, with a high spatiotemporal resolution in a naturalistic context, and is a powerful tool for analyzing the relationship between the animal’s behaviors and its brain functions. Macaque monkeys are excellent non-human primate models, especially for studying neuroscience. Due to the lack of a dataset allowing training of a deep neural network for the macaque’s markerless motion capture in the naturalistic context, it has been challenging to apply this technology for macaques-based studies. In this study, we created MacaquePose, a novel open dataset with manually labeled body part positions for macaques in naturalistic scenes, consisting of >13,000 images, refined by researchers. We show that the pose estimation performance of an artificial neural network trained with the dataset is close to that of a human-level. The MacaquePose will provide a platform for innovative behavior analysis for non-human primate.
Loss of RpoS results in attenuatedEscherichia colicolonization of human intestinal organoids and a competitive disadvantage within the germ-free mouse intestine
Authors: Barron Madeline R. , Cieza Roberto J. , Hill David R. , Huang Sha , Yadagiri Veda K. , Spence Jason R. , Young Vincent B.
Published: August 2020

Pluripotent stem-cell-derived human intestinal organoids (HIOs) are three-dimensional, multicellular structures that model a previously uncolonized, naïve intestinal epithelium in anin vitrosystem. We recently demonstrated that microinjection of the non-pathogenicEscherichia colistrain, ECOR2, into HIOs induced morphological and functional maturation of the HIO epithelium, including increased secretion of mucins and cationic antimicrobial peptides. In the current work, we use ECOR2 as a biological probe to investigate the bacterial response to colonization of the HIO lumen. InE. coliand other Gram-negative bacteria, adaptation to environmental stress is regulated by the general stress response sigma factor, RpoS. We generated an isogenic ∆rpoSECOR2 mutant to compare challenges faced by a bacterium during colonization of the HIO lumen relative to the germ-free mouse intestine, which is currently the best available system for studying the initial establishment of bacterial populations within the gut. We demonstrate that loss of RpoS significantly decreases the ability of ECOR2 to colonize HIOs, though it does not prevent colonization of germ-free mice. Rather, the ∆rpoSECOR2 exhibits a fitness defect in the germ-free mouse intestine only in the context of microbial competition. These results indicate that HIOs pose a differentially restrictive luminal environment toE. coliduring colonization, thus increasing our understanding of the HIO model system as it pertains to studying the establishment of intestinal host-microbe symbioses.

Importance

Technological advancements have and will continue to drive the adoption of organoid-based systems for investigating host-microbe interactions within the human intestinal ecosystem. UsingE. colideficient in the RpoS-mediated general stress response, we demonstrate that the type or severity of microbial stressors within the HIO lumen differ from those of thein vivoenvironment of the germ-free mouse gut. This study provides important insight into the nature of the HIO microenvironment from a microbiological standpoint.
Structure-function characterization of the conserved regulatory mechanism of theEscherichia coliM48-metalloprotease BepA
Authors: Bryant Jack A. , Cadby Ian T. , Chong Zhi-Soon , Sevastsyanovich Yanina R. , Morris Faye C. , Cunningham Adam F. , Kritikos George , Meek Richard W. , Banzhaf Manuel , Chng Shu-Sin , Lovering Andrew L. , Henderson Ian R.
Published: August 2020

The asymmetric Gram-negative outer membrane (OM) is the first line of defence for bacteria against environmental insults and attack by antimicrobials. The key component of the OM is lipopolysaccharide, which is transported to the surface by the essential lipopolysaccharide transport (Lpt) system. Correct folding of the Lpt system component LptD is regulated by a periplasmic metalloprotease, BepA. Here we present the crystal structure of BepA fromEscherichia coli,solved to a resolution of 2.18 Å, in which the M48 protease active site is occluded by an active site plug. Informed by our structure, we demonstrate that free movement of the active site plug is essential for BepA function, suggesting that the protein is auto-regulated by the active site plug, which is conserved throughout the M48 metalloprotease family. Targeted mutagenesis of conserved residues reveals that the negative pocket and the TPR cavity are required for function and degradation of the BAM complex component BamA under conditions of stress. Lastly, we show that loss of BepA causes disruption of OM lipid asymmetry, leading to surface exposed phospholipid.

Importance

M48 metalloproteases are widely distributed in all domains of life.E. colipossesses four members of this family located in multiple cellular compartments. The functions of these proteases are not well understood. Recent investigations revealed that one family member, BepA, has an important role in the maturation of a central component of the LPS biogenesis machinery. Here we present the structure of BepA and the results of a structure guided mutagenesis strategy, which reveal the key residues required for activity.
Inhibition ofCampylobacter jejunibiofilm formation by D-amino acids
Authors: Elgamoudi Bassam A. , Taha  , Korolik Victoria
Published: August 2020

The ability of bacterial pathogens to form biofilms is an important virulence mechanism in relation to its pathogenesis and transmission. Biofilms play a crucial role in survival in unfavourable environmental conditions, act as reservoirs of microbial contamination and antibiotic resistance. For intestinal pathogenCampylobacter jejuni, biofilms are considered to be a contributing factor in transmission through the food chain and currently, there are no known methods for intervention. Here we present an unconventional approach to reducing biofilm formation byC. jejuniby the application of D-amino acids (DAs), and L-amino acids (LAs). We found that DAs and not LAs, except L-alanine, reduced biofilm formation by up to 70%. The treatment ofC. jejunicells with DAs changed the biofilm architecture and reduced the appearance of amyloid-like fibrils. In addition, a mixture of DAs enhanced antimicrobial efficacy of D-Cycloserine (DCS) up to 32% as compared with DCS treatment alone. Unexpectedly, D-alanine was able to reverse the inhibitory effect of other DAs as well as that of DCS. Furthermore, L-alanine and D-tryptophan decreased transcript levels of peptidoglycan biosynthesis enzymes alanine racemase (alr) and D-alanine-D-alanine ligase (ddlA) while D-serine was only able to decrease the transcript levels ofalr. Our findings suggest that a combination of DAs could reduce biofilm formation, viability and persistence ofC. jejunithrough dysregulation ofalrandddlA.
Midcell localization of PBP4 ofEscherichia colimodulates the timing of divisome assembly
Authors: Verheul Jolanda , Lodge Adam , Yau Hamish C.L. , Liu Xiaolong , Liu Xinwei , Solovyova Alexandra S. , Typas Athanasios , Banzhaf Manuel , Vollmer Waldemar , Blaauwen Tanneke den
Published: August 2020

Insertion of new material into theEscherichia colipeptidoglycan (PG) sacculus between the cytoplasmic membrane and the outer membrane requires a well-organized balance between synthetic and hydrolytic activities to maintain cell shape and avoid lysis. The hydrolytic enzymes outnumber the enzymes that insert new PG by far and very little is known about their specific function. Here we show that the DD-carboxy/endopeptidase PBP4 localizes in a PBP1A/LpoA and FtsEX dependent fashion at midcell during septal PG synthesis. Midcell localization of PBP4 requires its non-catalytic domain 3 of unknown function, but not the activity of PBP4 or FtsE. Microscale thermophoresis with isolated proteins shows that domain 3 is needed for the interaction with NlpI, but not PBP1A or LpoA.In vivocrosslinking experiments confirm the interaction of PBP4 with PBP1A and LpoA. We propose that PBP4 functions together with the amidases AmiA and B to create denuded glycan strands to attract the initiator of septal PG synthesis, FtsN. Consistent with this model, we found that the divisome assembly at midcell was significantly affected in cells lacking PBP4.

IMPORTANCE

Peptidoglycan biosynthesis is a major target for antibacterials. The covalently closed peptidoglycan mesh, called sacculus, protects the bacterium from lysis due to its turgor. Sacculus growth is facilitated by the balanced activities of synthases and hydrolases, and disturbing this balance leads to cell lysis and bacterial death. Because of the large number and possible redundant functions of peptidoglycan hydrolases, it has been difficult to decipher their individual functions. In this paper we show that the DD-endopeptidase PBP4 localizes at midcell during septal peptidoglycan synthesis inEscherichia coliand is important for the timing of the assembly of the division machinery. This shows that inhibition of certain hydrolases could weaken the cells and might enhance antibiotic action.
Bi-directional encoding of context-based odor signals and behavioral states by the nucleus of the lateral olfactory tract neurons
Authors: Tanisumi Yuta , Shiotani Kazuki , Hirokawa Junya , Sakurai Yoshio , Manabe Hiroyuki
Published: August 2020

The nucleus of the lateral olfactory tract (nLOT) is not only a part of the olfactory cortex that receives olfactory sensory inputs from the olfactory bulb, but also one of the cortical amygdala areas that regulates motivational behaviors. To examine how the neural ensemble activity of the nLOT is modulated by motivational processes that occur during various states of learned goal-directed behaviors, we recorded nLOT spike activities of mice performing odor-guided go/no-go tasks for obtaining a water reward. We found that the majority of the nLOT neurons exhibited sharp go-cue excitation and persistent no-go-cue inhibition responses triggered by an odor onset. The bi-directional cue encoding introduced nLOT population response dynamics and provided a high odor decoding accuracy before executing cue-odor-evoked behaviors. The go-cue preferred neurons were also activated in the reward drinking state, indicating context-based odor-outcome associations. These findings suggest that the nLOT neurons play an important role in the translation from context-based odor information to appropriate behavioral motivation.
Intestinal inflammation and altered gut microbiota associated with inflammatory bowel disease renders mice susceptible toClostridioides difficilecolonization and infection
Authors: Abernathy-Close Lisa , Barron Madeline R. , George James M. , Dieterle Michael G. , Vendrov Kimberly C. , Bergin Ingrid I. , Young Vincent B.
Published: August 2020

Clostridioides difficilehas emerged as a noteworthy pathogen in patients with inflammatory bowel disease (IBD). Concurrent IBD and CDI is associated with increased morbidity and mortality compared to CDI alone. IBD is associated with alterations of the gut microbiota, an important mediator of colonization resistance toC. difficile. Here, we describe and utilize a mouse model to explore the role of intestinal inflammation in susceptibility toC. difficilecolonization and subsequent disease severity in animals with underlying IBD.Helicobacter hepaticus, a normal member of the mouse gut microbiota, was used to trigger inflammation in the distal intestine akin to human IBD in mice that lack intact IL-10 signaling. Development of IBD resulted in a distinct intestinal microbiota community compared to non-IBD controls. We demonstrate that in this murine model, IBD was sufficient to render mice susceptible toC. difficilecolonization. Mice with IBD were persistently colonized byC. difficile, while genetically identical non-IBD controls were resistant toC. difficilecolonization. Concomitant IBD and CDI was associated with significantly worse disease than unaccompanied IBD. IL-10-deficient mice maintained gut microbial diversity and colonization resistance toC. difficilein experiments utilizing an isogenic mutant ofH. hepaticusthat does not trigger intestinal inflammation. These studies in mice demonstrate that the IBD-induced microbiota is sufficient forC. difficilecolonization and that this mouse model requires intestinal inflammation for inducing susceptibility to CDI in the absence of other perturbations, such as antibiotic treatment.

IMPORTANCE

The incidence of CDI continues to increase significantly among patients with IBD, independent of antibiotic use, yet the relationship between IBD and increased risk for CDI remains to be understood. However, antibiotic-induced perturbations of the gut microbiota may mask mechanisms specific to IBD-inducedC. difficilesusceptibility and infection. Our study sought to describe and utilize a mouse model to specifically explore the relationship between the IBD-induced gut microbial community and susceptibility toC. difficilecolonization and CDI development. We demonstrate that IBD is sufficient forC. difficilecolonization and infection in mice and results in significantly worse disease than IBD alone, representing a murine model that recapitulates human IBD and CDI comorbidity. Furthermore, this model requires IBD-induced inflammation to sculpt a microbiota permissible toC. difficilecolonization. Use of this model will aid in developing new clinical approaches to predict, diagnose, and treatC. difficileinfection in the IBD population.
COVID-19 case-fatality rate and demographic and socioeconomic influencers: a worldwide spatial regression analysis based on country-level data
Authors: Cao Yang , Hiyoshi Ayako , Montgomery Scott
Published: August 2020

We used the COVID-19 dataset obtained from the Our World in Data website and investigated the associations between COVID-19 CFR and nine country-level indices of 209 countries/territories using the Matern correlation regression model. Spatial dependence among the data was controlled using the latitude and longitude of the centroid of the countries/territories. Stratified analyses were conducted by economic level and COVID-19 testing policy. The average of country/territory-specific COVID-19 CFR is about 2-3% worldwide, which is higher than previously reported at 0.7-1.3%. Statistically significant associations were observed between COVID-19 CFR and population size and proportion of female smokers. The open testing policies are associated with decreased CFR. Strictness of anti-COVID-19 measures was not statistically significantly associated with CFR overall, but the higher stringency index was associated with higher CFR in higher income countries with active testing policies. The statistically significant association between population size and COVID-19 CRF suggests the healthcare strain and lower treatment efficiency in countries with large populations. The observed association between smoking in females and COVID-19 CFR might be due to that the proportion of female smokers reflected broadly income level of a country. When testing is warranted and healthcare resources are sufficient, strict quarantine and/or lockdown measures might result in excess deaths in underprivileged populations.
Isolation Considered Epidemiological Model for the Prediction of COVID-19 Trend in Tokyo, Japan
Authors: Utamura Motoaki , Koizumi Makoto , Kirikami Seiichi
Published: August 2020

Background

Coronavirus Disease 2019 (COVID19) currently poses a global public health threat. Although no exception, Tokyo, Japan was affected at first by only a small epidemic. Medical collapse nevertheless nearly happened because no predictive method existed for counting patients. A standard SIR epidemiological model and its derivatives predict susceptible, infectious, and removed (recovered/deaths) cases but ignore isolation of confirmed cases. Predicting COVID19 trends with hospitalized and infectious people in field separately is important to prepare beds and develop quarantine strategies.

Methods

Time-series COVID19 data from February 28 to May 23, 2020 in Tokyo were adopted for this study. A novel epidemiological model based on delay differential equation was proposed. The model can evaluate patients in hospitals and infectious cases in the field. Various data such as daily new cases, cumulative infections, patients in hospital, and PCR test positivity ratios were used to examine the model. This approach derived an alternative formulation equivalent to the standard SIR model. Its results were compared quantitatively with those of the present isolation model.

Results

The basic reproductive number, inferred as 2.30, is a dimensionless parameter composed of modeling parameters. Effects of intervention to mitigate the epidemic spread were assessed a posteriori. An exit policy of how and when to release a statement of emergency was also assessed using the model. Furthermore, results suggest that the rapid isolation of infectious cases has a large potential to effectively mitigate the spread of infection and restores social and economic activities safely.

Conclusions

A novel mathematical model was proposed and examined using COVID19 data for Tokyo. Results show that shortening the period from infection to hospitalization is effective against outbreak without rigorous public health intervention and control. Faster and precise case cluster detection and wider and quicker introduction of testing measures are strongly recommended.
Job insecurity, financial threat and mental health in the COVID-19 context: The buffer role of perceived social support
Authors: Alcover Carlos-María , Salgado Sergio , Nazar Gabriela , Ramírez-Vielma Raúl , González-Suhr Carolina
Published: August 2020

The social distancing, confinement and quarantine adopted since March 2020 to confront the COVID-19 pandemic have affected multiple vital areas, and specially work, business and productive activities. Prior research has highlighted the relation between perceptions of risk in employment and its concomitant financial risk with a myriad of consequences for people’s well-being and health. In order to analyze the potential negative consequences of temporary layoffs, downsizing or closure of companies and businesses, and the consequent insecurity about the continuity of employment, the aim of this study is twofold. Firstly, to analyze the relations between the perceptions of job insecurity and financial threat and overall mental health during the first month of the COVID-19 pandemic in a sample of the Chilean adult population. And secondly, to identify the potential buffer effect of perceived social support on this relation. To analyze this, we carried out a cross-sectional study on a non-probabilistic sample aimed at a general Chilean adult population. The results show that both perceptions of job insecurity and financial threat are associated with a decline in perceived mental health. Additionally, results indicate a moderate buffer effect of perceived social support relative to the size of the social network. Thus, in relation to job insecurity and financial threat, the network size mitigates the association of both with the decline in perceived mental health. The theoretical and applied scope of these findings are analyzed, and their challenges and limitations are discussed.
Detection of Toxoplasmic Encephalitis in HIV Positive Patients in Urine with Hydrogel Nanoparticles
Authors: Steinberg Hannah E. , Bowman Natalie M. , Diestra Andrea , Ferradas Cusi , Russo Paul , Clark Daniel E. , Zhu Deanna , Magni Ruben , Malaga Edith , Diaz Monica , Pinedo-Cancino Viviana , Asayag Cesar Ramal , Calderón Maritza , Carruthers Vern B , Liotta Lance A. , Gilman Robert H. , Luchini Alessandra ,   the Toxoplasmosis working group in Peru and Bolivia
Published: August 2020

Background

Diagnosis of toxoplasmic encephalitis (TE) is challenging under the best clinical circumstances. The poor sensitivity of quantitative polymerase chain reaction (qPCR) forToxoplasmain blood and CSF and the limited availability of molecular diagnostics and imaging technology leaves clinicians in resource-limited settings with few options other than empiric treatment.

Methology/Principle Findings

Here we describe proof of concept for a novel urine diagnostics for TE using Poly-N-isoproplyacrylamide nanoparticles dyed with Reactive Blue-221 to concentrate antigens, substantially increasing the limit of detection. After nanoparticle-concentration, a standard western blotting technique with a monoclonal antibody was used for antigen detection. Limit of detection was 7.8pg/ml and 31.3pg/ml ofT. gondiiantigens GRA1 and SAG1, respectively. To characterize this diagnostic approach, 164 hospitalized HIV-infected patients with neurological symptoms compatible with TE were tested for 1)T. gondiiserology (121/147, positive samples/total samples tested), 2) qPCR in cerebrospinal fluid (11/41), 3) qPCR in blood (10/112), and 4) urinary GRA1 (30/164) and SAG1 (12/164). GRA1 appears to be superior to SAG1 for detection of TE antigens in urine. Fifty-one HIV-infected,T. gondiiseropositive but asymptomatic persons all tested negative by nanoparticle western blot and blood qPCR, suggesting the test has good specificity for TE for both GRA1 and SAG1. In a subgroup of 44 patients, urine samples were assayed with mass spectrometry parallel-reaction-monitoring (PRM) for the presence ofT. gondiiantigens. PRM identified antigens in 8 samples, 6 of which were concordant with the urine diagnostic.

Conclusion/Significances

Our results demonstrate nanoparticle technology’s potential for a noninvasive diagnostic test for TE. Moving forward, GRA1 is a promising target for antigen based diagnostics for TE.

Author Summary

Toxoplasmic Encephalitis is a debilitating, yet highly treatable illness, classically seen in person living with HIV lacking treatment. Prompt diagnosis ensures the best outcome possible for patients, but remains a challenge: requiring invasive specimen collection, lacking necessary sensitivity, demanding significant technical skills and substantial infrastructure. Here we offer proof of concept of a diagnostic approach that is minimally invasive, using a urine-based approach that concentratesT. gondiiantigens with hydrogel mesh nanoparticles to improve □sensitivity for detection by western blot. □
Factors associated with accelerated resting heart rate among college freshmen : a cross-sectional study
Authors: You Qiqi , Wang Tiantian , Jiang Qingqing , Zhang Qiumei , Cao Shiyi
Published: August 2020

Objective

This study aimed to investigate the prevalence of accelerated resting heart rates (RHRs) among freshmen in a university in Wuhan and to explore the influencing factors.

Methods

We conducted a cross-sectional survey and physical examinations in a university in Wuhan from 2015 to 2017, including 12428 freshmen. A binary logistic regression model was undertaken to identify the influencing factors associated with their accelerated RHRs.

Results

The prevalence of accelerated RHRs was 47.5% among the 12428 freshmen surveyed. Accelerated RHR of freshmen was related to female (odds ratio [OR]: 1.484, 95% confidence interval [95% CI]: 1.368 - 1.610, P < 0.001) and high blood pressure (OR: 2.709, 95% CI: 2.212 - 3.318, P < 0.001). Compared with rural students, accelerated RHR was more likely to occur in urban students (OR: 1.452, 95% CI: 1.333 - 1.583, P < 0.001). Additionally, students who came from the central and the eastern regions (OR: 1.452, 95% CI: 1.254 - 1.682, P < 0.001; OR: 1.363, 95% CI: 1.149 - 1.618, P < 0.001), rather than who came from the western regions, were more likely to have accelerated RHRs.

Conclusions

Students with accelerated RHRs made up a high proportion of college freshmen entering the university in 2015 – 2017 in Wuhan. For people aged around 18 years, more attention was needed to pay to RHRs and specific measures such as blood pressure management were required in advance to prevent accelerated RHRs.

Key questions

What is already known about this subject?

Accelerated resting heart rate (RHR) could significantly increase the risk of suffering from cardiovascular diseases (CVDs). However, little research had reported the influencing factors associated with accelerated RHR among the young around 18 years old.

What does this study add?

We conducted a survey on freshmen to investigate the influencing factors associated with accelerated RHR, so as to provide early warning information for the occurrence of CVDs in a visual way.

How might this impact on clinical practice?

This study might serve as a reminder to young people to pay more attention to RHRs and provide early warning information about CVDs.
Lifelong Ulk1-mediated autophagy deficiency in muscle induces mitochondrial dysfunction and contractile weakness
Authors: Nichenko Anna S. , Sorensen Jacob R. , Southern W. Michael , Qualls Anita E. , Schifino Albino G. , McFaline-Figueroa Jennifer , Blum Jamie E. , Thalacker-Mercer Anna E. , Greising Sarah M. , Call Jarrod A.
Published: August 2020

The accumulation of damaged mitochondria due to insufficient autophagy has been implicated in the pathophysiology of sarcopenia resulting in reduced contractile and metabolic function. Ulk1 is an autophagy-related kinase that initiates autophagosome assembly and may also play a role in autophagosome degradation (i.e., autophagy flux), but the contribution of Ulk1 to healthy muscle aging is unclear. We found that Ulk1 phosphorylation declines in both human and mouse muscle tissue with age, therefore the purpose of this study was to investigate the role of Ulk1-mediated autophagy in skeletal muscle aging. At age 22 months (80% survival rate), muscle contractile and metabolic function were assessed using electrophysiology in muscle specific Ulk1 knockout mice (MKO) and their littermate controls (LM). Specific peak-isometric torque of the ankle dorsiflexors (normalized by tibialis anterior muscle cross-sectional area) and specific force of the fast-twitch extensor digitorum longus muscles were reduced in MKO mice compared to LM mice (p<0.03). Permeabilized muscle fibers from MKO mice had greater mitochondrial content, yet lower mitochondrial oxygen consumption and greater reactive oxygen species production compared to fibers from LM mice (p≤ 0.04). Altered neuromuscular junction innervation patterns and changes in autophagosome numbers and/or flux in muscles from MKO may have contributed to decrements in contractile and metabolic function. Results from this study support an important role of Ulk1-mediated autophagy in skeletal muscle with age, reflecting Ulk1’s dual role in maintaining mitochondrial integrity through autophagosome assembly and degradation. A lifetime of insufficient Ulk-1-mediated autophagy in skeletal muscle exacerbates age-related contractile and metabolic dysfunction.
α-Synuclein plasma membrane localization correlates with cellular phosphatidylinositol polyphosphate levels
Authors: Eichmann Cédric , Jacob Reeba Susan , Dema Alessandro , Mercadante Davide , Selenko Philipp
Published: August 2020

The Parkinson’s disease protein α-synuclein (αSyn) promotes membrane fusion and fission by interacting with various negatively charged phospholipids. Despite postulated roles in endocytosis and exocytosis, plasma membrane (PM) interactions of αSyn are poorly understood. Here, we show that phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylinositol 3,4,5-trisphosphate (PIP3), two highly acidic components of inner PM leaflets, mediate plasma membrane localization of endogenous pools of αSyn in A2780, HeLa, SH-SY5Y and SK-MEL-2 cells. We demonstrate that αSyn binds reconstituted PIP2-membranes in a helical conformationin vitroand that PIP2synthesizing kinases and hydrolyzing phosphatases reversibly redistribute αSyn in cells. We further delineate that αSyn-PM targeting follows phosphoinositide-3 kinase (PI3K)-dependent changes of cellular PIP2and PIP3levels, which collectively suggests that phosphatidylinositol polyphosphates contribute to αSyn’s cellular function(s) at the plasma membrane.
A protease-mediated mechanism regulates the cytochromec6/ plastocyanin switch inSynechocystissp. PCC 6803
Authors: García-Cañas Raquel , Giner-Lamia Joaquín , Florencio Francisco J. , López-Maury Luis
Published: August 2020

After the Great Oxidation Event (GOE), iron availability was greatly decreased and photosynthetic organisms evolved several alternative proteins and mechanisms. One of these proteins, plastocyanin, is a type I blue-copper protein that can replace cytochromec6as a soluble electron carrier between cytochromeb6fand photosystem I. In most cyanobacteria, expression of these two alternative proteins is regulated by copper availability, but the regulatory system remains unknown. Herein, we provide evidence that the regulatory system is composed of a BlaI/CopY family transcription factor (PetR) and a BlaR membrane protease (PetP). PetR repressespetE(plastocyanin) expression and activatespetJ(cytochromec6), while PetP controls PetR levelsin vivo. Using whole-cell extracts, we demonstrated that PetR degradation requires both PetP and copper. Transcriptomic analysis revealed that the PetRP system regulates only four genes (petE,petJ,slr0601, andslr0602), highlighting its specificity. Furthermore, the presence ofpetEandpetRPin early branching cyanobacteria indicates that acquisition of these genes could represent an early adaptation to decreased iron bioavailability following the GOE.

Significance Statement

After the appearance of oxygenic photosynthesis, Fe became oxidized and its solubility and availability were greatly decreased. This generated a problem for most organisms since they are strongly dependent on Fe, especially photosynthetic organisms. In response, organisms evolved alternatives to Fe-containing proteins such as plastocyanin, a copper protein that substitutes for cytochromec6in photosynthesis. Expression of these two proteins in cyanobacteria is regulated by Cu availability, but the regulatory system remains unknown. Herein, we describe the regulatory system for these alternative proteins in photosynthesis in cyanobacteria. The mechanism involves a transcription factor (PetR) and a membrane protease (PetP) that degrades PetR in the presence of Cu.
SARS-CoV-2 protein subunit vaccination elicits potent neutralizing antibody responses
Authors: Mandolesi Marco , Sheward Daniel J , Hanke Leo , Ma Junjie , Pushparaj Pradeepa , Perez Vidakovics Laura , Kim Changil , Loré Karin , Castro Dopico Xaquin , Coquet Jonathan M , McInerney Gerald , Karlsson Hedestam Gunilla B , Murrell Ben
Published: August 2020

The outbreak and spread of SARS-CoV-2 (Severe Acute Respiratory Syndrome coronavirus 2), the cause of coronavirus disease 2019 (COVID-19), is a current global health emergency and a prophylactic vaccine is needed urgently. The spike glycoprotein of SARS-CoV-2 mediates entry into host cells, and thus is a target for neutralizing antibodies and vaccine design. Here we show that adjuvanted protein immunization with SARS-CoV-2 spike trimers, stabilized in prefusion conformation, results in potent antibody responses in mice and rhesus macaques with neutralizing antibody titers orders of magnitude greater than those typically measured in serum from SARS-CoV-2 seropositive humans. Neutralizing antibody responses were observed after a single dose, with exceptionally high titers achieved after boosting. Furthermore, neutralizing antibody titers elicited by a dose-sparing regimen in mice were similar to those obtained from a high dose regimen. Taken together, these data strongly support the development of adjuvanted SARS-CoV-2 prefusion-stabilized spike protein subunit vaccines.
Independent mechanisms of temporal and linguistic cue correspondence benefiting audiovisual speech processing
Authors: Fiscella Sara , Cappelloni Madeline S , Maddox Ross K
Published: August 2020

When listening is difficult, seeing the face of the talker aids speech comprehension. Faces carry both temporal (low-level physical correspondence of mouth movement and auditory speech) and linguistic (learned physical correspondences of mouth shape (viseme) and speech sound (phoneme)) cues. Listeners participated in two experiments investigating how these cues may be used to process sentences when maskers are present. In Experiment I, faces were rotated to disrupt linguistic but not temporal cue correspondence. Listeners suffered a deficit in speech comprehension when the faces were rotated, indicating that visemes are processed in a rotation-dependent manner, and that linguistic cues aid comprehension. In Experiment II, listeners were asked to detect pitch modulation in the target speech with upright and inverted faces that either matched the target or masker speech such that performance differences could be explained by binding, an early multisensory integration mechanism distinct from traditional late integration. Performance in this task replicated previous findings that temporal integration induces binding, but there was no behavioral evidence for a role of linguistic cues in binding. Together these experiments point to temporal cues providing a speech processing benefit through binding and linguistic cues providing a benefit through late integration.
A tissue-engineered human trabecular meshwork hydrogel for advanced glaucoma disease modeling
Authors: Li Haiyan , Bagué Tyler , Kirschner Alexander , Weisenthal Robert W. , Patteson Alison E. , Annabi Nasim , Stamer W. Daniel , Ganapathy Preethi S. , Herberg Samuel
Published: August 2020

Purpose

Abnormal human trabecular meshwork (HTM) cell function and extracellular matrix (ECM) remodeling contribute to HTM stiffening in primary open-angle glaucoma (POAG). Most current cellular HTM model systems do not sufficiently replicate the complex native three dimensional (3D) cell-ECM interface, which makes them less than ideal to investigate POAG pathology. Tissue-engineered protein-based hydrogels are ideally positioned to overcome shortcomings of current models. Here, we report a novel biomimetic HTM hydrogel and test its utility as a POAG disease model.

Methods

HTM hydrogels were engineered by mixing normal donor-derived HTM cells with collagen type I, elastin-like polypeptide and hyaluronic acid, each containing photoactive functional groups, followed by UV light-activated free-radical crosslinking. Glaucomatous conditions were induced with dexamethasone (DEX), and therapeutic effects of the Rho-associated kinase (ROCK) inhibitor Y27632 on cytoskeletal organization and tissue-level function, contingent on HTM cell-ECM interactions, were assessed.

Results

DEX exposure increased HTM hydrogel contractility, f-actin and alpha smooth muscle actin abundance and rearrangement, ECM remodeling, and fibronectin and collagen type IV deposition, all contributing to HTM hydrogel condensation and stiffening consistent with recent data from normal vs. glaucomatous HTM tissue. Y27632 treatment produced precisely the opposite effects and attenuated the DEX-induced pathologic changes, resulting in HTM hydrogel relaxation and softening.

Conclusions

We have developed a biomimetic HTM hydrogel model for detailed investigation of 3D cell-ECM interactions under normal and simulated glaucomatous conditions. Its bidirectional responsiveness to pharmaceutical challenge and rescue suggests promising potential to serve as screening platform for new POAG treatments with focus on HTM biomechanics.
Cohesin in space and time: architecture and oligomerizationin vivo
Authors: Xiang Siheng , Koshland Douglas
Published: August 2020

Cohesin helps mediate sister chromatid cohesion, chromosome condensation, DNA repair and transcription regulation. Cohesin can tether two regions of DNA and can also extrude DNA loops. We interrogated cohesin architecture, oligomerization state and function of cohesin oligomersin vivothrough proximity-dependent labeling of cohesin domains. Our results suggest that the hinge and head domains of cohesin both bind DNA, and that cohesin coiled coils bend, bringing the head and hinge together to form a butterfly conformation. Our data also suggest that cohesin efficiently oligomerizes on and off DNA. The levels of oligomers and their distribution on chromosomes are cell cycle regulated. Cohesin oligomerization is blocked by mutations in distinct domains of Smc3p and Mcd1p, or depletion of Pds5p. This unusual subset of mutations specifically blocks the maintenance of cohesion and condensation, suggesting that cohesin oligomerization plays a critical role in these biological functions.
Effect of β-chitosan on the binding interaction between SARS-CoV-2 S-RBD and ACE2
Authors: Alitongbieke Gulimiran , Li Xiu-min , Wu Qi-Ci , Lin Zhi-Chao , Huang Jia-Fu , Xue Yu , Liu Jing-Na , Lin Jin-Mei , Pan Tao , Chen Yi-Xuan , Su Yi , Zhang Guo-Guang , Leng Bo , Liu Shu-Wen , Pan Yu-Tian
Published: August 2020

SARS-CoV-2 invades human respiratory epithelial cells via an interaction between its spike RBD protein (SARS-CoV-2 S-RBD) and the host cell receptor angiotensin converting enzyme II (ACE2). Blocking this interaction provides a potent approach to preventing and controlling SARS-CoV-2 infection. In this work, the ability of β-chitosan to block the binding interaction between SARS-CoV-2 S-RBD and ACE2 was investigated. The inhibitory effect of β-chitosan on inflammation induced by the SARS-CoV-2 S-RBD was also studied. Native-PAGE analysis indicated that β-chitosan could bind with ACE2 and the SARS-CoV-2 S-RBD and a conjugate of β-chitosan and ACE2 could no longer bind with the SARS-CoV-2 S-RBD. HPLC analysis suggested that a conjugate of β-chitosan and the SARS-CoV-2 S-RBD displayed high binding affinity without dissociation under high pressure (40 MPa) compared with that of β-chitosan and ACE2. Furthermore, immunofluorescent staining of Vero E6 cells and lungs from hACE2 mice showed that the presence of β-chitosan prevented SARS-CoV-2 S-RBD from binding to ACE2. Meanwhile, β-chitosan could dramatically suppress the inflammation caused by the presence of the SARS-CoV-2 S-RBD bothin vitroandvivo. Moreover, the decreased expression of ACE2 caused by β-chitosan treatment was restored by addition of TAPI-1, an inhibitor of the transmembrane protease ADAM17. Our findings demonstrated that β-chitosan displays an antibody-like function capable of neutralizing the SARS-CoV-2 S-RBD and effectively preventing the binding of the SARS-CoV-2 S-RBD to ACE2. Moreover, ADAM17 activation induced by β-chitosan treatment can enhance the cleavage of the extracellular domain of ACE2, releasing the active ectodomain into the extracellular environment, which can prevent the binding, internalization, and degradation of ACE2 bound to the SARS-CoV-2 S-RBD and thus diminish inflammation. Our study provides an alternative avenue for preventing SARS-CoV-2 infection using β-chitosan.
CD20 as a gatekeeper of the resting stage of human B cells
Authors: Kläsener Kathrin , Jellusova Julia , Andrieux Geoffroy , Salzer Ulrich , Böhler Chiara , Steiner Sebastian N. , Albinus Jonas B. , Cavallari Marco , Süß Beatrix , Boerries Melanie , Voll Reinhard E. , Wollscheid Bernd , Reth Michael
Published: August 2020

CD20 is a B cell specific membrane protein and a target of therapeutic antibodies such as rituximab (RTX)1. In spite of the prominent usage of anti-CD20 antibodies in the clinic little is known about the biological function of CD202. Here we show that CD20 controls the nanoscale organization of receptors on the surface of resting B lymphocytes. A CRISPR/Cas-based ablation of CD20 in Ramos B cells results in a relocalisation of the IgM B cell antigen receptor (IgM-BCR) and the co-receptor CD19. The resulting IgM-BCR/CD19 signaling synapse leads to transient B cell activation followed by plasma cell differentiation. Similarly to CD20-deficient Ramos cells, naïve human B cells treated with rituximab in vitro or isolated from patients during rituximab administration display hallmarks of transient activation characterized by the formation of the IgM-BCR/CD19 signaling synapse, followed by CD19 and IgM-BCR downregulation. Moreover, increased expression of specific plasma cell genes can be observed after rituximab treatment in relapsed CLL patients. In summary we identify CD20 as a gatekeeper of the resting state on human B cells and demonstrate that a disruption of the nanoscale organization of the B cell surface via CD20 deletion or anti-CD20 treatment profoundly alters B cell fate.