bluuebunny/crossref_metadata_2025 huggingface dataset:
Ongoing long-lasting insecticide-treated net distribution efforts are insufficient to maintain high rates of use among children in rural Uganda
Authors: Cote Claire M. , Goel Varun , Muhindo Rabbison , Baguma Emmanuel , Ntaro Moses , Shook-Sa Bonnie E. , Reyes Raquel , Staedke Sarah G. , Mulogo Edgar M. , Boyce Ross M.
Published: March 2021

Background

Long-lasting insecticide-treated nets (LLINs) remain a cornerstone of malaria control, but optimal distribution strategies to sustain universal coverage are not well-defined

Methods

We conducted a cross-sectional survey of 2,190 households in the highlands of western Uganda to examine LLIN source and use among children age with elevation and distance to clinic being the primary variables of interest.

Results

We found that only 64.7% (95% CI 64.0 – 65.5%) of children were reported to have slept under a LLIN the previous night. Compared to those living <1 km from a health center, households at ≥ 2 km were less likely to report the child sleeping under a LLIN (RR 0.86, 95% CI: 0.83 – 0.89, p<.001). Households located farther from a health center received a higher proportion of nets from government distributions compared to households living closer to health centers.

Conclusions

Continuous, clinic-based distribution efforts were insufficient to sustain high rates of LLIN use among children between mass distribution campaigns. More frequent campaigns and complementary approaches are required to achieve and maintain universal LLIN coverage in rural areas.
Computed-tomography estimates of interaural mismatch in insertion depth and scalar location in bilateral cochlear-implant users
Authors: Goupell Matthew J. , Noble Jack H. , Phatak Sandeep A. , Kolberg Elizabeth , Cleary Miranda , Stakhovskaya Olga A. , Jensen Kenneth K. , Hoa Michael , Kim H. Jeffrey , Bernstein Joshua G. W.
Published: March 2021

Hypothesis

We hypothesized that the bilateral cochlear-implant (BI-CI) users would have a range of interaural insertion-depth mismatch because of different physical placements or characteristics of the arrays, but less than half of electrodes would have less than 75° or 3 mm of interaural insertion-depth mismatch. We also hypothesized that interaural insertion- depth mismatch would be more prevalent nearer the apex, when electrodes were located outside of scala tympani (i.e., possible interaural scalar mismatch), and when the arrays were a mix of pre-curved and straight types.

Background

Brainstem neurons in the superior olivary complex are exquisitely sensitive to interaural differences, the cues to sound localization. These binaurally sensitive neurons rely on interaurally place-of-stimulation-matched inputs at the periphery. BI-CI users may have interaural differences in insertion depth and scalar location, causing interaural place- of-stimulation mismatch that impairs binaural abilities.

Methods

Insertion depths and scalar locations were calculated from temporal-bone computed-tomography (CT) scans of 107 BI-CI users (27 Advanced Bionics, 62 Cochlear, and 18 Med-El). Each subject had either both pre-curved, both straight, or one of each type of array (mixed).

Results

The median interaural insertion-depth mismatch was 23.4° or 1.3 mm. Relatively large interaural insertion-depth mismatch sufficient to disrupt binaural processing occurred for about 15% of electrode pairs [defined as >75° (13.0% of electrode pairs) or >3 mm (19.0% of electrode pairs)]. There was a significant three-way interaction of insertion depth, scalar location, and array type. Interaural insertion-depth mismatch was most prevalent when electrode pairs were more apically located, electrode pairs had interaural scalar mismatch (i.e., one in Scala Tympani, one in Scala Vestibuli), and when the arrays were both pre-curved.

Conclusion

Large interaural insertion-depth mismatch can occur in BI-CI users. For new BI-CI users, improved surgical techniques to avoid interaural insertion-depth and scalar mismatch is recommended. For existing BI-CI users with interaural insertion-depth mismatch, interaural alignment of clinical frequency allocation tables by an audiologist might remediate any negative consequences to spatial-hearing abilities.
When thinking you are better leads to feeling worse: Self-other asymmetries in pro-social behavior and increased anxiety during Covid-19
Authors: Helion Chelsea , Ulichney Virginia , Smith David V. , Jarcho Johanna
Published: March 2021

Self-favoring beliefs (e.g., that one tends to perform better than peers) are generally associated with positive psychological outcomes like increased self-esteem and resilience. However, this tendency may be problematic in the context of collective action problems, wherein individuals are reliant on others’ pro-social behaviors to achieve larger goals. We examined this question in the context of the Covid-19 pandemic, and recruited participants (n= 1023) from a university community in Spring 2020. We found evidence for a self-peer asymmetry, such that participants reported that they were doing more to stop the spread of the disease and were more pro-socially motivated than peers. Actual peer reports indicated that these were overestimations. This self-enhancement tendency comes with a cost: the perceived self-peer asymmetry mediated the relationship between Covid-specific worry and general anxiety during the early lockdown period. This indicates that while believing one is doing more than others may be maladaptive in collective action problems.
Trends in homelessness and injection practices among young urban and suburban people who inject drugs: 1997-2017
Authors: Hotton Anna L. , Mackesy-Amiti Mary Ellen , Boodram Basmattee
Published: March 2021

Background

Among young people who inject drugs (PWID) homelessness is associated with numerous adverse psychosocial and health consequences, including risk of relapse and overdose, psychological distress and suicidality, limited treatment access, and injection practices that increase the risk of HIV and hepatitis C (HCV) transmission. Homeless PWID may also be less likely to access sterile syringes through pharmacies or syringe service programs.

Methods

This study applied random-effects meta-regression to examine trends over time in injection risk behaviors and homelessness among young PWID in Chicago and surrounding suburban and rural areas using data from 11 studies collected between 1997 and 2017. In addition, subject-level data were pooled to evaluate the effect of homelessness on risk behaviors across all studies using mixed effects logistic and negative binomial regression with random study effects.

Results

There was a significant increase in homelessness among young PWID over time, consistent with the general population trend of increasing youth homelessness. In mixed-effects regression, homelessness was associated with injection risk behaviors (receptive syringe sharing, syringe mediated sharing, equipment sharing) and exchange sex, though we detected no overall changes in risk behavior over time.

Conclusions

Increases over time in homelessness among young PWID highlight a need for research to understand factors contributing to youth homelessness to inform HIV/STI, HCV, and overdose prevention and intervention services for this population.
Basivertebral nerve block during vertebral augmentation: An alternative approach to intraprocedural pain management
Authors: Santoro Giovanni C. , Kulkarni Siddhant , Lien Kenny
Published: March 2021

Vertebral compression fractures secondary to osteoporosis can be treated with vertebral augmentation. Since intraprocedural pain is common during vertebral body endplate manipulation, these procedures are often carried out using conscious sedation or general anesthesia. Research has shown that the vertebral endplates are innervated by the basivertebral nerve, which has been successfully targeted via radiofrequency ablation to treat chronic vertebrogenic lower back pain. With this physiology in mind, we treated ten patients with vertebral compression using intraosseous basivertebral nerve block as the primary intraprocedural analgesia. In this case series, we describe our successful experience with this novel approach.
Self-Reported Stress and Questionnaires in People With Autism Spectrum Disorder: a Systematic Review
Authors: Thoen Anoushka , Steyaert Jean , Alaerts Kaat , Evers Kris , Damme Tine Van
Published: March 2021

Background

To gain more insight into the experience of stress in individuals with ASD, it is important to use appropriate self-report questionnaires. The goal of this systematic review was to provide an overview of these.

Method

The PRISMA guidelines were followed and four online databases were systematically searched.

Results

Seven questionnaires have been used previously in individuals with ASD. None of the 22 included studies intended to assess the psychometric properties, leading towards scarce evidence concerning their reliability and validity in this population.

Conclusions

It is important to consider which concept of stress one aims to measure as not all questionnaires cover the same aspects of stress. Further research concerning psychometric properties of the questionnaires in this population is required.
Lower help-seeking intentions and subsequent depressive symptoms among adolescents with high autistic traits: A population-based cohort study
Authors: Hosozawa Mariko , Yamasaki Syudo , Ando Shuntaro , Endo Kaori , Morimoto Yuko , Kanata Sho , Fujikawa Shinya , Cable Noriko , Iso Hiroyasu , Hiraiwa-Hasegawa Mariko , Kasai Kiyoto , Nishida Atsushi
Published: March 2021

Background

Adolescents with high autistic traits in the general population are at increased risk of depression. Despite the importance of help-seeking for early intervention, evidence on help-seeking intentions among this population is scarce.

Aims

To examine the help-seeking intentions and preferences for depression by the level of autistic traits in adolescents, and test how help-seeking intentions mediate the association between autistic traits and depressive symptoms.

Method

Participants were from the Tokyo Teen Cohort, a population-based cohort in Japan. They were classified into two groups according to parent-rated autistic traits measured by the short-version of the Autism-Spectrum Quotient (≥6 as AQhigh). Help-seeking intentions and preferences were assessed at age 12 using a depression vignette. Depressive symptoms were self-rated at age 14 using the Short Mood and Feelings Questionnaire. Data were analysed using multivariable regression analysis and structural equation modelling.

Results

Of the 2,505 adolescents in the study, 200 (8%) were classified as AQhigh. In the AQhigh-group, 40% of the adolescents reported not having help-seeking intentions, although 93% recognised the need and 97% had someone to rely on. Parents of the AQhigh-group also reported fewer help-seeking intentions. The AQhigh-group was associated with an increased risk of not having help-seeking intentions (OR 1.83, 95%CI 1.35–2.49), which explained 19% of the above association.

Conclusions

Lower help-seeking intentions among adolescents with high autistic traits partially explained their increased risk for subsequent depressive symptoms. Interventions to promote help-seeking intentions among this population should involve both adolescents and their parents and ideally be provided before adolescence.
Performance of RT-PCR on saliva specimens compared to nasopharyngeal swabs for the detection of SARS-CoV-2 in children: A prospective comparative clinical trial
Authors: Fougère Yves , Schwob Jean Marc , Miauton Alix , Hoegger Francesca , Opota Onya , Jaton Katia , Brouillet Rene , Greub Gilbert , Genton Blaise , Gehri Mario , Taddeo Ilaria , D’Acremont Valérie , Asner Sandra A.
Published: March 2021

Background

Saliva RT-PCR is an attractive alternative for the detection of SARS-CoV-2 in adults with much less known in children.

Methods

Children and adolescents with symptoms suggestive of COVID-19 were prospectively enrolled in a comparative clinical trial of saliva and nasopharyngeal (NP) RT-PCR between November and December 2020. Detection rates and sensitivities of saliva and NP RT-PCR were compared. Participants with discordant NP and saliva RT-PCR results including viral load (VL) were also analyzed.

Result

Out of 405 patients enrolled, 397 patients had two tests performed. Mean age was 12.7 years (range 1.2-17.9). Detection rates were 22.9% (95%CI 18.8-27.1%) by saliva RT-PCR, 25.4% (21.2-29.7%) by NP RT-PCR, and 26.7% (22.4-31.1%) by any test. The sensitivity of saliva was 85.2% (78.2-92.1%) when using NP as the gold standard; in contrast, when saliva was considered the gold standard, the sensitivity of NP was 94.5% (89.8-99.2%).For a NP RT-PCR VL threshold of ≥103 and ≥104 copies/ml, sensitivity of saliva increases to 88.7% and 95.2% respectively. Sensitivity of saliva and NP swabs was respectively 89.5% and 95.3% in patient with symptoms less than 4 days (p=0.249) and 70.0% and 95.0% in those with symptoms ≥ 4 to 7 days (p=0.096). The 15 patients who had an isolated positive NP RT-PCR were significantly younger (p=0.034), had a lower NP VL (median 5.6×103 vs 3.9×107, p<0.001), and were not able to drool saliva at the end of the sampling (p=0.002). VLs were significantly lower with saliva PCR than with NP RT-PCR (median 8.7 cp/ml x104; IQR 1.2×104-5.2×105; vs median 4.0×107cp/ml; IQR 8.6×105-1.x108; p<0.001).

Conclusion

Saliva PCR shows diagnostic performances close to NP RT-PCR for SARS-CoV2 detection in most symptomatic outpatient children and adolescents.
FRONTLINE COMMUNITIES AND SARS-COV-2 - MULTI-POPULATION MODELING WITH AN ASSESSMENT OF DISPARITY BY RACE/ETHNICITY USING ENSEMBLE DATA ASSIMILATION
Authors: Fleurantin Emmanuel , Sampson Christian , Maes Daniel Paul , Bennet Justin , Fernandez-Nunez Tayler , Marx Sophia , Evensen Geir
Published: March 2021

Abstract

The COVID-19 pandemic has imposed many strenuous effects on the global economy, community, and medical infrastructure. Since the out- break, researchers and policymakers have scrambled to develop ways to identify how COVID-19 will affect specific sub-populations so that good public health decisions can be made. To this end, we adapt the work of Evensenet al[1] which introduces a SEIR model that incorporates an age-stratified contact matrix, a time dependent effective reproduction numberR, and uses ensemble data assimilation to estimate model parameters. The adaptation is an extension of Evensen’s modeling framework, in which we model sub-populations with varying risks of contracting SARS-CoV-2 (the virus that causes COVID-19) in a particular state, each with a characteristic age-stratified contact matrix. In this work, we will focus on 9 U.S. states as well as the District of Columbia. We estimate the effective reproductive number as a function of time for our different sub-populations and then divide them into two groups: frontline communities (FLCs) and the complement (NFLCs). Our model will account for mixing both within populations (intra-population mixing) and between populations (inter-population mixing). Our data is conditioned on the daily numbers of accumulated deaths for each sub-population. We aim to test and demonstrate methodologies that can be used to assess critical metrics of the pandemic’s evolution which are difficult to directly measure. The output may ultimately be of use to measure the success or failures of the pandemic response and provide experts and policymakers a tool to create better plans for a future outbreak or pandemic. We consider the results of this work to be a reanalysis of pandemic evolution across differently affected sub-populations which may also be used to improve modeling and forecasts.
Clinical presentation and in-hospital outcomes of older patients hospitalized with COVID-19 in Montreal, Canada: a retrospective review
Authors: Couture Sandrine , Lepage Marc-Antoine , Godard-Sebillotte Claire , Sourial Nadia , Talbot-Hamon Catherine , Kremer Richard , Grunbaum Ami
Published: March 2021

Background

Older adults are more vulnerable to severe infection and mortality due to COVID-19. They often have atypical presentations of the disease without respiratory symptoms, which makes early diagnosis clinically challenging. We aimed to compare the baseline characteristics, presentation, and disease course of older and younger patients hospitalized with COVID-19.

Methods

The charts of 429 consecutive patients hospitalized in Montreal, Canada, with PCR-confirmed COVID-19 were retrospectively reviewed. Baseline health, presentation, in-hospital complications, and outcomes were recorded. Desegregation by age was performed to compare older (≥70) versus younger (<70) individuals.

Results

Older patients presented with more comorbidities compared to younger patients as captured by the Charlson Comorbidity Index (mean 6 vs 2), including higher rates of cardiovascular, cerebrovascular, chronic obstructive pulmonary, and chronic kidney disease. Older patients were less likely than younger patients to present with cough (27% vs 47%) or dyspnea (33% vs 48%). Fifty-two (52%) had no respiratory symptoms on presentation compared to 32% in the younger group (p<0.001); however, they were more likely to present with geriatric syndromes such as delirium (29% vs 7%), functional decline (14% vs 0.6%), or falls (15% vs 5%). Twelve (12%) of older patients presented with a geriatric syndrome as their sole symptom compared to 3% in the younger group (p=0.002). Older adults were more likely to develop acute kidney injury (35% vs 22%), malnutrition (9% vs 4%), delirium (29% vs 17%) and hypernatremia (32% vs 17%). They had higher in-hospital mortality (33% vs 13%, p<0.001).

Discussion

Older adults presenting to hospital with COVID-19 commonly have no respiratory symptoms and can present with only a geriatric syndrome. A new geriatric syndrome in an older person should trigger isolation and evaluation for COVID-19. Furthermore, older adults are particularly vulnerable to complications related to dehydration, warranting early initiation of multidisciplinary care.
Is bigger always better? Neither body size nor aggressive behavior are good predictors to measure the degree of specialization of hummingbird interaction networks in rocky outcrops
Authors: Claudino Ricardo Marcelino , Antonini Yasmine , Martins Cristiane , do Vale Beirão Marina , Braga Érika Martins , de Azevedo Cristiano Schetini
Published: March 2021

Interspecific competition can strongly influence community structure and shape niche breadth and overlap. One of the main factors that determine the hummingbird community structure is competition for food. Hummingbirds functional attributes, such as beak length and body mass, influence nectar acquisition in the flowers, shaping foraging niches according to hummingbird dominance and foraging strategy. This study evaluates how the hummingbirds’ functional and behavioral attributes are related to plants assemblage in rocky outcrops’ habitats. We tested the following hypothesis: H1) Functional traits (beak length and body mass) are related to the richness and frequency of pollen grain morphotypes carried by hummingbirds; H2) Dominant and territorial hummingbirds carry a lower richness and frequency of pollen types when compared to subordinate hummingbirds, and H3) Hummingbird species carry different types of pollen grains. We conducted the study between September 2018 and March 2019 in aCampo Rupestre(rocky outcrops) in Southeastern Brazil. Hummingbirds were captured with a trap built based on trapdoors. We recorded their beak size and body masses, marked with commercial bird rings and ink on parts of the body, and then released. Behavioral responses to artificial feeders were collected regarding each visit’s time and duration and the outcome of aggressive interactions. The pollen adhered to the body parts was collected and identified in the laboratory. Our results showed that neither body size nor aggressive behaviors influenced pollen richness and frequency in rocky outcrops. Beak length was the most important hummingbirds’ attribute that influenced pollen richness, but not pollen frequency. Short-billed hummingbirds carried the greatest richness of pollen grains. Pollen grain richness and frequency were not related to hummingbird body mass or aggressive behavior. The hummingbird-pollen grain interaction network has shown to be generalized in the pollen grain transport. We conclude that hummingbirds’ beak length is the central morphological variable to measure pollen grain transport. It has direct implications for the pollination of different plant species.
Dynamic signatures of the Eureka effect: An EEG study
Authors: Lu Yiqing , Singer Wolf
Published: March 2021

The Eureka effect refers to the common experience of suddenly solving a problem. Here we study this effect in a pattern recognition paradigm that requires the segmentation of complex scenes and recognition of objects on the basis of Gestalt rules and prior knowledge. In the experiments both sensory evidence and prior knowledge were manipulated in order to obtain trials that do or do not converge towards a perceptual solution. Subjects had to detect objects in blurred scenes and signal recognition with manual responses. Neural dynamics were analyzed with high-density Electroencephalography (EEG) recordings. The results show significant changes of neural dynamics with respect to spectral distribution, coherence, phase locking, and fractal dimensionality. The Eureka effect was associated with increased coherence of oscillations in the alpha and theta band over widely distributed regions of the cortical mantle predominantly in the right hemisphere. This increase in coherence was associated with a decrease of beta band activity over parietal and central regions, and with a decrease of alpha power over frontal and occipital areas. In addition, there was a lateralized reduction of fractal dimensionality for activity recorded from the right hemisphere. These results suggest that the transition towards the solution of a perceptual task is mainly associated with a change of network dynamics in the right hemisphere that is characterized by enhanced coherence and reduced complexity. We propose that the Eureka effect requires cooperation of cortical regions involved in working memory, creative thinking, and the control of attention.
Male attention allocation depends on social context
Authors: Burridge Shelby D. , Schlupp Ingo , Makowicz Amber M.
Published: March 2021

Attention, although limited, is a mechanism used to filter large amounts of information and determine what stimuli are most relevant at a particular moment. In dynamic social environments, multiple individuals may play a pivotal role in any given interaction where a male’s attention may be divided between a rival, a current mate, and/or future potential mates. Here, we investigated impacts of the social environment on attention allocation in male sailfin mollies,Poecilia latipinna, which are a part of a sexual-unisexual mating system with the Amazon molly,Poecilia formosa. We asked: 1) Does the species of female influence the amount of attention a male allocates to her? And 2) Is a male’s attention towards his mate influenced by different social partners? Males direct more attention toward a stimulus female when she was a conspecific. We also show that males perceive a larger male as a more relevant stimulus to pay attention to than a smaller male, and a conspecific female as a more relevant stimulus compared to a heterospecific female. Our results show differential allocation of attention is dependent upon multiple components of the social environment in which an individual interacts.

Significance

This study investigates how attention is allocated in males when presented with social distractions. Assuming that attentional capacity is finite, males may face a tradeoff between different cognitive-demanding stimuli, such as rival males and potential future mates, when mating. Here, we show that male attention allocation in both intra- and intersexual interactions is multifaceted and context dependent. This suggests that individuals within the social environment vary in how meaningful (i.e., able to capture attention) they are to males during mating encounters. Understanding how social partners can cause a shift of attention away from a mating opportunity is essential to understanding the influence of the social context on sexual selection.
Kinetic pathway of ATP-induced DNA interactions of ParA2, a protein essential for segregation ofVibrio choleraechromosome 2
Authors: Chodha Satpal S. , Brooks Adam C. , Davis Peter , Ramachandran Revathy , Chattoraj Dhruba K , Hwang Ling Chin
Published: March 2021

Vibrio choleraechromosome 2 (Chr2) requires its own ParABS system for segregation. Without it,V. choleraebecomes nonviable and loses pathogenicity. ParA2 of Chr2 is a Walker-type ATPase that is the main driver of Chr2 segregation. Most of our understanding of ParA function comes from studying plasmid partition systems. How ParA provides the motive force in segregation of chromosomes, which are much larger than plasmids, is less understood and different models have been proposed. Here we analyzedin vivobehavior and kinetic properties of ParA2 using cell imaging, biochemical and biophysical approaches. ParA2 formed an asymmetric gradient in the cell that localized dynamically in the cell cycle. We found that ParA2 dimers bind ATP and undergo a slow conformational change to an active DNA-binding state, similar to P1 ParA. The presence of DNA catalyzes ParA2 conformational change to allow cooperative binding of active ParA2 dimers to form higher-order oligomers on DNA. Nucleotide exchange rates were also slow, thus providing a control of ParA2 recruitment and dynamic localizations. Although highly conserved in biochemical properties, ParA2 showed faster overall ATP cycling and DNA-rebinding rates than plasmid ParAs, suggesting that this could be shared kinetic features among chromosomal ParAs to regulate the transport of a much larger DNA cargo.
Therapeutic immunization againstHelicobacter pyloriinfection in BALB/c mice induced by a multi-epitope vaccine based on computer-aided design
Authors: Ma Junfei , Wang Shuying , Ji Qianyu , Liu Qing
Published: March 2021

Background

Combined antibiotic regimens have caused problems such as increasing antimicrobial resistance toH. pyloriand intestinal flora disturbance. Vaccination is a great alternative approach, but also faces the limited immune response induced by monovalent vaccines. Therefore, the development of multi-epitope vaccines is promising immunotherapy to controlH. pyloriinfection.

Objective

To develop a multi-epitope vaccine and evaluate its therapeutic efficacy againstH. pyloriinfection.

Materials and Methods

The B and T cell epitopes from UreB, FlaA, AlpB, SabA, and HpaA were linked for producing 2 multi-epitope vaccines (CTB-S3 and CTB-S5) by a structural evaluation based on computer-aided design. The abilities to produce antigen-specific antibodies and neutralizing antibodies of CTB-S3 and CTB-S5 were evaluated in BALB/c mice. After that, their therapeutic efficacy was explored inH. pylori-infectedmice.

Results

CTB-S3 or CTB-S5 could induce high levels of specific antibodies against UreB, FlaA, AlpB, SabA, HpaA, and neutralizing antibodies againstH. pyloriurease and adhesion. Also, oral therapeutic immunization with CTB-S3 or CTB-S5 could decreaseH. pyloricolonization and reduce stomach damage; the protection was correlated withH. pylori-specific IgG, SIgA antibodies, and CD4+T cell immune response.

Conclusions

Our study developed a multi-epitope vaccine based on a computer-aided design. The CTB-S3 and CTB-S5 vaccines may be promising therapeutic candidate vaccines againstH. pyloriinfection and provide a reference for vaccine design of other pathogens.
ksrates: positioning whole-genome duplications relative to speciation events inKSdistributions
Authors: Sensalari Cecilia , Maere Steven , Lohaus Rolf
Published: March 2021

We presentksrates, a user-friendly command-line tool to position ancient whole-genome duplication (WGD) events with respect to speciation events in a phylogeny by comparing paralog and orthologKSdistributions derived from genomic or transcriptomic sequences, while adjusting for substitution rate differences among the lineages involved.

Availability and implementation

ksratesis implemented in Python 3 and as a Nextflow pipeline. The source code, Singularity and Docker containers, documentation and tutorial are available viahttps://github.com/VIB-PSB/ksrates.

Contact

steven.maere@ugent.vib.be,rolf.lohaus@ugent.vib.be
Spatial alanine metabolism determines local growth dynamics ofEscherichia colicolonies
Authors: Díaz-Pascual Francisco , Lempp Martin , Nosho Kazuki , Jeckel Hannah , Jo Jeanyoung K. , Neuhaus Konstantin , Hartmann Raimo , Jelli Eric , Hansen Mads Frederik , Price-Whelan Alexa , Dietrich Lars E.P. , Link Hannes , Drescher Knut
Published: March 2021

Bacteria commonly live in spatially structured biofilm assemblages, which are encased by an extracellular matrix. Metabolic activity of the cells inside biofilms causes gradients in local environmental conditions, which leads to the emergence of physiologically differentiated subpopulations. Information about the properties and spatial arrangement of such metabolic subpopulations, as well as their interaction strength and interaction length scales are lacking, even for model systems likeEscherichia colicolony biofilms grown on agar-solidified media. Here, we use an unbiased approach, based on temporal and spatial transcriptome and metabolome data acquired duringE. colicolony biofilm growth, to study the spatial organization of metabolism. We discovered that alanine displays a unique pattern among amino acids and that alanine metabolism is spatially and temporally heterogeneous. At the anoxic base of the colony, where carbon and nitrogen sources are abundant, cells secrete alanineviathe transporter AlaE. In contrast, cells utilize alanine as a carbon and nitrogen source in the oxic nutrient-deprived region at the colony mid-height,viathe enzymes DadA and DadX. This spatially structured alanine cross-feeding influences cellular viability and growth in the cross-feeding-dependent region, which shapes the overall colony morphology. More generally, our results on this precisely controllable biofilm model system demonstrate a remarkable spatiotemporal complexity of metabolism in biofilms. A better characterization of the spatiotemporal metabolic heterogeneities and dependencies is essential for understanding the physiology, architecture, and function of biofilms.
Destabilization of β-cell FIT2 by saturated fatty acids contribute to ER stress and diabetes
Authors: Zheng Xiaofeng , Ho Qing Wei Calvin , Chua Minni , Stelmashenko Olga , Muralidharan Sneha , Torta Federico , Chew Elaine Guo Yan , Lian Michelle Mulan , Foo Jia Nee , Wenk Markus , Silver David L. , Berggren Per-Olof , Ali Yusuf
Published: March 2021

Western type diets are linked to obesity and diabetes partly because of their high saturated fatty acid (SFA) content. We found that SFAs, but not unsaturated fatty acids (USFAs), reduced the number of lipid droplets (LDs) within pancreatic β-cells. Mechanistically, SFAs but not USFAs disabled LD biogenesis by inducing palmitoylation and subsequent ERAD-C mediated degradation of LD formation protein, Fat storage-Inducing Transmembrane protein 2 (FIT2). Targeted ablation of FIT2 reduced β-cell LD numbers, lowered β-cell ATP levels, reduced Ca2+ signaling, downregulated β-cell transcription factors (RNA sequencing analysis), and exacerbated diet-induced diabetes in mice. Subsequent mass spectrometry studies revealed increased C16:0 ceramide accumulation in islets of mice lacking β-cell FIT2 under lipotoxic conditions. Inhibition of ceramide synthases ameliorated the enhanced ER stress. Overexpression of FIT2 increased number of intracellular LDs and rescued SFA-induced ER-stress and apoptosis thereby highlighting the protective role of FIT2 and LDs against β-cell lipotoxicity and diet-induced diabetes.
Dissecting the genetic architecture of quantitative traits using genome-wide identity-by-descent sharing
Authors: Fraimout Antoine , Guillaume Frédéric , Li Zitong , Sillanpää Mikko J. , Rastas Pasi , Merilä Juha
Published: March 2021

Additive and dominance genetic variances underlying the expression of quantitative traits are important quantities for predicting short-term responses to selection, but they are notoriously challenging to estimate in most non-model wild populations. Specifically, large-sized or panmictic populations may be characterized by low variance in genetic relatedness among individuals which in turn, can prevent accurate estimation of quantitative genetic parameters. We used estimates of genome-wide identity-by-descent (IBD) sharing from autosomal SNP loci to estimate quantitative genetic parameters for ecologically important traits in nine-spined sticklebacks (Pungitius pungitius) from a large, outbred population. Using empirical and simulated datasets, with varying sample sizes and pedigree complexity, we assessed the performance of different crossing schemes in estimating additive genetic variance and heritability for all traits. We found that low variance in relatedness characteristic of wild outbred populations with high migration rate can impair the estimation of quantitative genetic parameters and bias heritability estimates downwards. On the other hand, the use of a half-sib/full-sib design allowed precise estimation of genetic variance components, and revealed significant additive variance and heritability for all measured traits, with negligible dominance contributions. Genome-partitioning and QTL mapping analyses revealed that most traits had a polygenic basis and were controlled by genes at multiple chromosomes. Furthermore, different QTL contributed to variation in the same traits in different populations suggesting heterogenous underpinnings of parallel evolution at the phenotypic level. Our results provide important guidelines for future studies aimed at estimating adaptive potential in the wild, particularly for those conducted in outbred large-sized populations.
Host-derived Reactive Nitrogen Species mediate theCryptococcus neoformansyeast-to-titan switch via fungal-derived superoxide
Authors: Zhou Xin , Desanti Guillaume E. , May Robin C. , Dambuza Ivy M. , Ballou Elizabeth R.
Published: March 2021

In the host lung, the human fungal pathogenCryptococcus neoformansundergoes a morphological switch from small haploid yeast to large polyploid titan cell, contributing toC. neoformansvirulence. Titan cells are less readily phagocytosed and can survive host nitrosative and oxidative stresses. We and others previously showed that titanization is triggered by host-relevant signals including CO2and lung-resident bacteria, and addition of these factor is sufficient to induce titan cellsin vitro. Here we investigate the molecular mechanisms that drive this transition and demonstrate that host-derived immune signals can increase the degree and frequency of titanization. Specifically, host-relevant reactive nitrogen species increase the accumulation of endogenous superoxide within cryptococcal cells, particularly within nuclei, where it can cause genotoxic stress. Consistent with this, we observe the accumulation of Rad51 protein, a marker of the double strand break repair pathway, in titanizing cultures. Blocking superoxide accumulation inhibits titanization, yet titanization also requires superoxide detoxification through Superoxide Dismutase (SOD) activity. Loss of mitochondrial Sod2 activity locks cells in the yeast phase, while Sod1 is required for the production of viable titan daughter cells. We hypothesize that the redox responsive transcription factor Yap1 in part mediates this response by regulatingSOD2/SOD1. In addition, we show that Sod1 translocates to the nucleus, where it is likely involved in the detoxification of genotoxic superoxide. Together, these findings reveal a major new regulatory mechanism for the yeast-to-titan transition.

Author Summary

During fungal infection, host phagocytes produce reactive oxygen and nitrogen species (ROS/RNS), major determinants of infection outcome. Fungal pathogens have developed numerous strategies to neutralize and detoxify ROS, but RNS remain important effectors for infection control. In the lung, the human fungal pathogenCryptococcus neoformanscan undergo a morphological switch from small haploid yeast to large highly polyploid titan cells with increased ROS/RNS stress resistance, and the capacity to produce haploid or aneuploid daughters. Here, we report that RNS are a major signal driving the frequency and degree of titanization and act by increasing endogenous ROS within the fungus. We show that the accumulation of endogenous ROS is required for the yeast-to-titan transition, and is associated with increased genotoxic stress leading to polyploidy. Yet, failure to detoxify this ROS, either in mutants defective in Superoxide Dismutase activity or the oxidative stress response protein Yap1, impairs titan cell budding and reduces progeny viability. Therefore, the interface of exogenous RNS and endogenous ROS regulation during host-pathogen interaction represents an Achilles’ heel for this major human fungal pathogen.
miRNA-dependent poly(A) length control in uncoupling transcription and translation of haploid male germ cells
Authors: Tang Chong , Guo Mei , Shi Zhuoxing , Wang Zhuqing , Luo Chunhai , Chen Sheng , Ruan Fengying , Chen Zhichao , Yang Linfeng , Wei Xiongyi , Wu Chuanwen , Luo Bei , Lv Zhou , Huang Jin , Zhang Dong , Yu Cong , Gao Qiang , Zhang Ying , Yan Wei , Sun Fei
Published: March 2021

As one of the post-transcriptional regulatory mechanisms, transcription and translation’s uncoupling plays an essential role in development and adulthood physiology. However, it remains elusive how thousands of mRNAs get translationally silenced while stability is maintained for up to hours or even days before translation. In addition to oocytes and neurons, developing spermatids have significant uncoupling of transcription and translation for delayed translation. Therefore, spermiogenesis represents an excellentin vivomodel for investigating the mechanism underlying uncoupled transcription and translation. Through full-length poly(A) deep sequencing, we discovered dynamic changes in poly(A) length through deadenylation and re-polyadenylation. Deadenylation appeared to be mediated by microRNAs (miRNAs), and transcripts with shorter poly(A) tails tend to be sequestered into ribonucleoproteins (RNPs) for translational repression and stabilization. In contrast, re-polyadenylation allows for translocation of the translationally repressed transcripts from RNPs to polysomes for translation. Overall, our data suggest that miRNA-dependent poly(A) length control represents a novel mechanism underlying uncoupled translation and transcription in haploid male germ cells.
Preparing Frozen Tissue Sections for Staining
Authors: Rodig Scott J.
Published: March 2021

Cell-staining studies on mammalian tissue are often performed on frozen sections. This is the gentlest method for the preparation of samples and gives good preservation of cell structure and antigens. Its principal disadvantages are that the specimens must be stored frozen and a special microtome, known as a cryostat, is required. In addition, many clinical specimens are not available in this form, and most classical histological descriptions of tissue structure and pathology are based on the use of formalin-fixed, paraffin-embedded (FFPE) material.
Crystal symmetry for incommensurate helical and cycloidal modulations
Authors: Fabrykiewicz Piotr , Przeniosło Radosław , Sosnowska Izabela
Published: March 2021

A classification of magnetic superspace groups compatible with the helical and cycloidal magnetic modulations is presented. Helical modulations are compatible with groups from crystal classes 1, 2, 222, 4, 422, 3, 32, 6 and 622, while cycloidal modulations are compatible with groups from crystal classes 1, 2,mandmm2. For each magnetic crystal class, the directions of the symmetry-allowed (non-modulated) net ferromagnetic moment and electric polarization are given. The proposed classification of superspace groups is tested on experimental studies of type-II multiferroics published in the literature.
The manager’s conundrum in governing a farmers’ association
Authors: Ooi Sue Chern , Abdul Malak Siti Seri Delima , Che Ahmad Ayoib
Published: March 2021

Learning outcomes

The main objectives of this case are to provide an opportunity for case users to understand the organisational governance framework in a farmers' association and how to build an effective organisational board. More specifically, the teaching objectives of this case are as follows: to provide an overview of the functions of different types of governance structures in a farmers' association. To understand the importance of good governance practices in a farmers' association and for its stakeholders. To relate democratic theory, stakeholder theory, agency theory and stewardship theory with the governance practices of a farmers' association. To critically evaluate the board governance in a farmers' association and recommend measures to enhance the practices.

Case overview/synopsis

The teaching case presents the governance practices in a farmers' association in Malaysia, ZIX-PPK and the various governance challenges that emerged in the PPK subsequent to the appointment of politically affiliated directors. Prior to 2019, ZIX-PPK was an outstanding PPK under the helm of the General Manager, Khadijah. The PPK had continually been recognised as an exceptional and excellent PPK by the Farmers' Organisation Authority and the Muda Agricultural Development Authority. However, the Arahan Pendaftar Bil 1/2019 required changes to the governance structures of ZIX-PPK, with five new directors being appointed by the minister. The appointment threatened the independence and autonomy of ZIX-PPK and affected the dynamic of the board of directors. Khadijah had to search for measures that could improve the board governance in ZIX-PPK. The names, in this case, had been altered but the details were based on an actual event. The data were collected through interviews with key players and with reference to the minutes and other documentation of ZIX-PPK.

Complexity academic level

The teaching case can be used by students in higher education institutions at both undergraduate and postgraduate levels. The case may also be relevant for training purposes to farmers' associations and any non-profit organisations.

Subject code

CSS 1: Accounting and Finance.

Supplementary materials

Teaching notes are available for educators only.
Suitability of the high performance organization framework for Egyptian ICT companies: a replication study
Authors: Ateia Mohammed Azmy , El Galaly Saneya Abdelfattah , de Waal André
Published: March 2021

Purpose

The purpose of this paper is to answer the research question “Is the high-performance organization (HPO) Framework suitable for non-governmental private sector organizations, specifically the affiliates of international companies operating in the ICT sector in Egypt?”

Design/methodology/approach

The research concerns a replication study in which the HPO Questionnaire was used to collect data, and factor analysis was applied to evaluate the reliability and consistency of the HPO Framework. The research approach was the same as applied by de Waal et al. (2016), but this time the research population consisted of affiliates of international ICT companies, instead of local ICT companies as in the de Waal et al. (2016) study.

Findings

Data gathered by means of the HPO Questionnaire from managers of these affiliates were used to evaluate the reliability and internal consistency of the HPO Framework. The confirmatory factor analysis was done twice, once for the original 35-characteristic HPO Framework and once for the 26-characteristic HPO Framework as proposed by de Waal et al. (2016) for Egyptian local ICT companies. The study results clearly show the applicability of the original 35-characteristic HPO Framework for measuring the organizational strength and identifying performance-gaps of ICT companies that are affiliates of international organizations operating in Egypt.

Originality/value

This study adds to the growing HPO literature on developing countries and helps Egyptian ICT companies to adopt high-performance practices to be able to contribute more to the economic development of Egypt.
The role of perceived social media agility in customer engagement
Authors: Gligor David , Bozkurt Sıddık
Published: March 2021

Purpose

The concept of agility has been applied to several domains to help firms develop the capability to quickly adjust their operations to cope and thrive in environments characterized by frequent changes. Despite the soaring number of social media users and the benefits associated with agility in other domains, the application of agility in a social media context has yet to be explored. Further, little is known about how agility in a social media context impacts desirable customer-related attributes, such as customer engagement and customer-based brand equity (CBBE). This paper aims to address this gap by adapting the construct to social media (i.e. perceived social media agility) and exploring its impact on customer engagement and CBBE.

Design/methodology/approach

This paper conducted an online survey with 200 adult subjects. This paper used multivariate regression analyzes to empirically test a scale for perceived social media agility and explore its impact on CBBE and customer engagement, along with the moderating role of customer change-seeking behavior.

Findings

The study results show that perceived social media agility directly and indirectly (through customer engagement) positively influences CBBE. Also, results show that the positive impact of perceived social media agility on CBBE is further magnified for customers high on change-seeking. However, customer change-seeking does not affect the strength or direction of the impact of perceived social media agility on customer engagement.

Originality/value

This paper contributes to social media literature by adapting and testing a measurement scale for the construct of perceived social media agility and exploring its role in enhancing customer engagement and CBBE.