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Many people face high risk of PTSD after being injured, research finds

A significant number of injury survivors experience post-traumatic stress disorder, and better screening practices could help connect them to mental health services.




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Expanding the public health team: a cross-sector workforce

I’ve been talking a lot lately about the importance of working across sectors for public health — of not going it alone to tackle the imposing challenges before us. The ideal public health team is broad and includes not only public health professionals representing the essential services, but also professionals from other disciplines, the general public and students of all stripes.




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Federal funding for gun violence prevention research sparks hopes: Priorities, direction being explored

After more than 20 years of minimal funding, the U.S. is opening its purse strings to research on gun violence prevention.




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Moving Upstream to Impact Health: Building a Physician Workforce that Understands Social Determinants

Decades of rallying cries from professional societies, medical education and training programs, and government stakeholders have distilled the conversation of social determinants of health (SDOH) from theoretical proposals into practical solutions [1-3]. No longer standing on the precipice of change, we are now in the trenches. The nation's health care system recognizes SDOH as important drivers of health and is taking steps to address them in the practice environment.

More widespread action and attention by the health care system drives the need to train the next generation of physicians in the concepts and actions related to SDOH. This includes SDOH as a core part of the medical curriculum, offering clinical and research experiences and service in the community [4-5]. Unfortunately, to date only a handful of programs have brought this vision to fruition. Across the country, most programs offer educational content that is largely didactic and provided in short or one-time sessions [6]. Though a start, such approaches are insufficient to prepare the next generation of physicians for their important work ahead.

In New Orleans, the NOLA Hotspotters are an interdisciplinary group of medical, public health, nursing, and pharmacy students inspired by the work out of Camden, New Jersey, to "hot spot" patients with high utilization, which is often related to social needs [7]. While the results of the Camden program have been widely discussed following publication of their work, we argue the benefit of such a program exists beyond reduced emergency department visits or health care spending [8]. The...




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Developing a Workforce for Health in North Carolina: Planning for the Future

Among the many trends influencing health and health care delivery over the next decade, three are particularly important: the transition to value-based care and increased focus on population health; the shift of care from acute to community-based settings; and addressing the vulnerability of rural health care systems in North Carolina.




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A new cheiracanthid acanthodian from the Middle Devonian (Givetian) Orcadian Basin of Scotland and its biostratigraphic and biogeographical significance

A number of partial articulated specimens of Cheiracanthus peachi nov. sp. have been collected from the Mey Flagstone Formation and Rousay Flagstone Formation within the Orcadian Basin of northern Scotland. The new, robust-bodied species is mainly distinguished by the scale ornament of radiating grooves rather than ridges. Compared to other Cheiracanthus species in the Orcadian Basin, C. peachi nov. sp. has quite a short range making it a useful zone fossil. As well as describing the general morphology of the specimens, we have also described and figured SEM images of scales and histological sections of all elements, enabling identification of other, isolated remains. Of particular biological interest is the identification of relatively robust, tooth-like gill rakers. Finally, the species has also been identified from isolated scales in Belarus, where it appears earlier and has a longer stratigraphical range, implying the species evolved in the marine deposits of the east and migrated west into the Orcadian Basin via the river systems.




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Digging deeper: The influence of historical mining on Glasgow's subsurface thermal state to inform geothermal research

Studies of the former NE England coalfield in Tyneside demonstrated that heat flow perturbations in boreholes were due to the entrainment and lateral dispersion of heat from deeper in the subsurface through flooded mine workings. This work assesses the influence of historical mining on geothermal observations across Greater Glasgow. The regional heat flow for Glasgow is 60 mW m–2 and, after correction for palaeoclimate, is estimated as c. 80 mW m–2. An example of reduced heat flow above mine workings is observed at Hallside (c. 10 km SE of Glasgow), where the heat flow through a 352 m deep borehole is c. 14 mW m–2. Similarly, the heat flow across the 199 m deep GGC01 borehole in the Glasgow Geothermal Energy Research Field Site is c. 44 mW m–2. The differences between these values and the expected regional heat flow suggest a significant component of horizontal heat flow into surrounding flooded mine workings. This deduction also influences the quantification of deeper geothermal resources, as extrapolation of the temperature gradient above mine workings would underestimate the temperature at depth. Future projects should consider the influence of historical mining on heat flow when temperature datasets such as these are used in the design of geothermal developments.

Supplementary material: Background information on the chronology of historical mining at each borehole location and a summary of groundwater flow in mine workings beneath Glasgow are available at https://doi.org/10.6084/m9.figshare.c.4681100

Thematic collection: This article is part of the ‘Early Career Research’ available at: https://www.lyellcollection.org/cc/SJG-early-career-research




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Low-carbon GeoEnergy resource options in the Midland Valley of Scotland, UK

Scotland is committed to be a carbon-neutral society by 2040 and has achieved the important initial step of decarbonizing power production. However, more ambitious measures are required to fully decarbonize all of the electricity, transport and heating sectors.

We explore the potential to use low-carbon GeoEnergy resources and bioenergy combined with Carbon Capture and Storage (BECCS) in the Midland Valley area to decarbonize the Scottish economy and society. The Midland Valley has a long history of geological resource extraction and, as a result, the geology of the region is well characterized.

Geothermal energy and subsurface energy storage have the potential to be implemented. Some of them, such as gravity and heat storage, could re-use the redundant mining infrastructure to decrease investment costs. Hydrogen storage could be of particular interest as the Midland Valley offers the required caprock–reservoir assemblages. BECCS is also a promising option to reduce overall CO2 emissions by between 1.10 and 4.40 MtCO2 a–1. The Midland Valley has enough space to grow the necessary crops, but CO2 storage will most likely be implemented in North Sea saline aquifers. The studied aspects suggest that the Midland Valley represents a viable option in Scotland for the exploitation of the majority of low-carbon GeoEnergy resources.

Thematic collection: This article is part of the ‘Early Career Research’ available at: https://www.lyellcollection.org/cc/SJG-early-career-research





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RNA Interference-Based Screen Reveals Concerted Functions of MEKK2 and CRCK3 in Plant Cell Death Regulation

A wide variety of intrinsic and extrinsic cues lead to cell death with unclear mechanisms. The infertility of some death mutants often hurdles the classical suppressor screens for death regulators. We have developed a transient RNA interference (RNAi)-based screen using a virus-induced gene silencing approach to understand diverse cell death pathways in Arabidopsis (Arabidopsis thaliana). One death pathway is due to the depletion of a MAP kinase (MAPK) cascade, consisting of MAPK kinase kinase 1 (MEKK1), MKK1/2, and MPK4, which depends on a nucleotide-binding site Leu-rich repeat (NLR) protein SUMM2. Silencing of MEKK1 by virus-induced gene silencing resembles the mekk1 mutant with autoimmunity and defense activation. The RNAi-based screen toward Arabidopsis T-DNA insertion lines identified SUMM2, MEKK2, and Calmodulin-binding receptor-like cytoplasmic kinase 3 (CRCK3) to be vital regulators of RNAi MEKK1-induced cell death, consistent with the reports of their requirement in the mekk1-mkk1/2-mpk4 death pathway. Similar with MEKK2, overexpression of CRCK3 caused dosage- and SUMM2-dependent cell death, and the transcripts of CRCK3 were up-regulated in mekk1, mkk1/2, and mpk4. MEKK2-induced cell death depends on CRCK3. Interestingly, CRCK3-induced cell death also depends on MEKK2, consistent with the biochemical data that MEKK2 complexes with CRCK3. Furthermore, the kinase activity of CRCK3 is essential, whereas the kinase activity of MEKK2 is dispensable, for triggering cell death. Our studies suggest that MEKK2 and CRCK3 exert concerted functions in the control of NLR SUMM2 activation and MEKK2 may play a structural role, rather than function as a kinase, in regulating CRCK3 protein stability.




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The Circadian Clock Influences the Long-Term Water Use Efficiency of Arabidopsis

In plants, water use efficiency (WUE) is a complex trait arising from numerous physiological and developmental characteristics. Here, we investigated the involvement of circadian regulation in long-term WUE in Arabidopsis (Arabidopsis thaliana) under light and dark conditions. Circadian rhythms are generated by the circadian oscillator, which provides a cellular measure of the time of day. In plants, the circadian oscillator contributes to the regulation of many aspects of physiology, including stomatal opening, rate of photosynthesis, carbohydrate metabolism, and developmental processes such as the initiation of flowering. We investigated the impact of the misregulation of numerous genes encoding various components of the circadian oscillator on whole plant, long-term WUE. From this analysis, we identified a role for the circadian oscillator in WUE. It appears that the circadian clock contributes to the control of transpiration and biomass accumulation. We also established that the circadian oscillator within guard cells can contribute to long-term WUE. Our experiments indicate that knowledge of circadian regulation will be important for developing crops with improved WUE.




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Specific Lhc Proteins Are Bound to PSI or PSII Supercomplexes in the Diatom Thalassiosira pseudonana

Despite the ecological relevance of diatoms, many aspects of their photosynthetic machinery remain poorly understood. Diatoms differ from the green lineage of oxygenic organisms by their photosynthetic pigments and light-harvesting complex (Lhc) proteins, the latter of which are also called fucoxanthin-chlorophyll proteins (FCP). These are composed of three groups of proteins: Lhcf as the main group, Lhcr that are PSI associated, and Lhcx that are involved in photoprotection. The FCP complexes are assembled in trimers and higher oligomers. Several studies have investigated the biochemical properties of purified FCP complexes, but limited knowledge is available about their interaction with the photosystem cores. In this study, isolation of stable supercomplexes from the centric diatom Thalassiosira pseudonana was achieved. To preserve in vivo structure, the separation of thylakoid complexes was performed by native PAGE and sucrose density centrifugation. Different subpopulations of PSI and PSII supercomplexes were isolated and their subunits identified. Analysis of Lhc antenna composition identified Lhc(s) specific for either PSI (Lhcr 1, 3, 4, 7, 10–14, and Lhcf10) or PSII (Lhcf 1–7, 11, and Lhcr2). Lhcx6_1 was reproducibly found in PSII supercomplexes, whereas its association with PSI was unclear. No evidence was found for the interaction between photosystems and higher oligomeric FCPs, comprising Lhcf8 as the main component. Although the subunit composition of the PSII supercomplexes in comparison with that of the trimeric FCP complexes indicated a close mutual association, the higher oligomeric pool is only weakly associated with the photosystems, albeit its abundance in the thylakoid membrane.




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MtSSPdb: A New Database for the Small Secreted Peptide Research Community




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Improving Crop Water-Use Efficiency Requires Optimizing the Circadian Clock




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Overcoming Algal Vitamin B12 Auxotrophy by Experimental Evolution




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Severe Pulmonary Hypertension Management Across Europe (PHAROS): an ERS Clinical Research Collaboration

The past 20 years have seen major advances in the understanding and treatment of pulmonary arterial hypertension (PAH; group 1 of the pulmonary hypertension (PH) clinical classification) [1]. A strong basis of knowledge has been acquired in: 1) large randomised clinical trials for drug development; 2) national registries for epidemiology and outcome; and 3) smaller studies on the pathophysiological mechanisms of the disease. This knowledge has been reviewed at World Symposia on Pulmonary Hypertension (the most recent in 2018 [2]) and summarised in European Respiratory Society (ERS)/European Society of Cardiology (ESC) clinical guidelines (the most recent in 2015 [3, 4]). We are, however, much less knowledgeable on specific aspects such as 1) the implementation of guidelines and access to therapies in different European countries; 2) the management of PH crises and progressive (acute on chronic) heart failure; and 3) other groups of PH, such as PH due to lung diseases. Therapeutic strategies also need to be optimised, in particular regarding the combination of drugs, the use of anticoagulants, the place for new medications targeting different pathophysiological pathways, etc.




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Forced oscillation technique for optimising PEEP in ventilated extremely preterm infants

Ventilatory settings are critical in mechanically ventilated extremely preterm newborn infants due to the risk of ventilation-induced lung injury (VILI) and the subsequent development of bronchopulmonary dysplasia (BPD) [1]. Positive end-expiratory pressure (PEEP) settings usually rely on blood gases, oxygen requirement, lung auscultation, evaluation of chest radiograph and assessment of the pressure/volume curves provided by ventilators. Studies of optimal PEEP settings in the surfactant-treated preterm infant in need of mechanical ventilation are limited and evidence-based clinical guidelines are sparse [2, 3]. A bedside method identifying the PEEP value that comprises maximal lung volume recruitment and minimising tissue overdistension could improve real-time optimisation of PEEP and potentially minimise the risk of VILI and BPD [4, 5].




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Apraxia of speech involves lesions of dorsal arcuate fasciculus and insula in patients with aphasia

Objective

To determine the contributions of apraxia of speech (AOS) and anomia to conversational dysfluency.

Methods

In this observational study of 52 patients with chronic aphasia, 47 with concomitant AOS, fluency was quantified using correct information units per minute (CIUs/min) from propositional speech tasks. Videos of patients performing conversational, how-to and picture-description tasks, word and sentence repetition, and diadochokinetic tasks were used to diagnose AOS using the Apraxia of Speech Rating Scale (ASRS). Anomia was quantified by patients' scores on the 30 even-numbered items from the Boston Naming Test (BNT).

Results

Together, ASRS and BNT scores accounted for 51.4% of the total variance in CIUs/min; the ASRS score accounted for the majority of that variance. The BNT score was associated with lesions in the left superior temporal gyrus, left inferior frontal gyrus, and large parts of the insula. The global ASRS score was associated with lesions in the left dorsal arcuate fasciculus (AF), pre- and post-central gyri, and both banks of the central sulcus of the insula. The ASRS score for the primary distinguishing features of AOS (no overlap with features of aphasia) was associated with less AF and more insular involvement. Only ~27% of this apraxia-specific lesion overlapped with lesions associated with the BNT score. Lesions associated with AOS had minimal overlap with the frontal aslant tract (FAT) (<1%) or the extreme capsule fiber tract (1.4%). Finally, ASRS scores correlated significantly with damage to the insula but not to the AF, extreme capsule, or FAT.

Conclusions

Results are consistent with previous findings identifying lesions of the insula and AF in patients with AOS, damage to both of which may create dysfluency in patients with aphasia.




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Optimizing Resources in Childrens Surgical Care: An Update on the American College of Surgeons' Verification Program

Surgical procedures are performed in the United States in a wide variety of clinical settings and with variation in clinical outcomes. In May 2012, the Task Force for Children’s Surgical Care, an ad hoc multidisciplinary group comprising physicians representing specialties relevant to pediatric perioperative care, was convened to generate recommendations to optimize the delivery of children’s surgical care. This group generated a white paper detailing the consensus opinions of the involved experts. Following these initial recommendations, the American College of Surgeons (ACS), Children’s Hospital Association, and Task Force for Children’s Surgical Care, with input from all related perioperative specialties, developed and published specific and detailed resource and quality standards designed to improve children’s surgical care (https://www.facs.org/quality-programs/childrens-surgery/childrens-surgery-verification). In 2015, with the endorsement of the American Academy of Pediatrics (https://pediatrics.aappublications.org/content/135/6/e1538), the ACS established a pilot verification program. In January 2017, after completion of the pilot program, the ACS Children’s Surgery Verification Quality Improvement Program was officially launched. Verified sites are listed on the program Web site at https://www.facs.org/quality-programs/childrens-surgery/childrens-surgery-verification/centers, and more than 150 are interested in verification. This report provides an update on the ACS Children’s Surgery Verification Quality Improvement Program as it continues to evolve.




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Implicit Bias in Pediatrics: An Emerging Focus in Health Equity Research




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Ahmed A, Fend PI, Gaensbauer JT, Reves RR, Khurana R, Salcedo K, Punnoose R, Katz DJ, for the TUBERCULOSIS EPIDEMIOLOGIC STUDIES CONSORTIUM. Interferon-{gamma} Release Assays in Children <15 Years of Age. Pediatrics. 2020:145(1):e20191930




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Deciphering Sex-Specific Genetic Architectures Using Local Bayesian Regressions [Genetics of Complex Traits]

Many complex human traits exhibit differences between sexes. While numerous factors likely contribute to this phenomenon, growing evidence from genome-wide studies suggest a partial explanation: that males and females from the same population possess differing genetic architectures. Despite this, mapping gene-by-sex (GxS) interactions remains a challenge likely because the magnitude of such an interaction is typically and exceedingly small; traditional genome-wide association techniques may be underpowered to detect such events, due partly to the burden of multiple test correction. Here, we developed a local Bayesian regression (LBR) method to estimate sex-specific SNP marker effects after fully accounting for local linkage-disequilibrium (LD) patterns. This enabled us to infer sex-specific effects and GxS interactions either at the single SNP level, or by aggregating the effects of multiple SNPs to make inferences at the level of small LD-based regions. Using simulations in which there was imperfect LD between SNPs and causal variants, we showed that aggregating sex-specific marker effects with LBR provides improved power and resolution to detect GxS interactions over traditional single-SNP-based tests. When using LBR to analyze traits from the UK Biobank, we detected a relatively large GxS interaction impacting bone mineral density within ABO, and replicated many previously detected large-magnitude GxS interactions impacting waist-to-hip ratio. We also discovered many new GxS interactions impacting such traits as height and body mass index (BMI) within regions of the genome where both male- and female-specific effects explain a small proportion of phenotypic variance (R2 < 1 x 10–4), but are enriched in known expression quantitative trait loci.




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Machine Learning Techniques for Classifying the Mutagenic Origins of Point Mutations [Methods, Technology, [amp ] Resources]

There is increasing interest in developing diagnostics that discriminate individual mutagenic mechanisms in a range of applications that include identifying population-specific mutagenesis and resolving distinct mutation signatures in cancer samples. Analyses for these applications assume that mutagenic mechanisms have a distinct relationship with neighboring bases that allows them to be distinguished. Direct support for this assumption is limited to a small number of simple cases, e.g., CpG hypermutability. We have evaluated whether the mechanistic origin of a point mutation can be resolved using only sequence context for a more complicated case. We contrasted single nucleotide variants originating from the multitude of mutagenic processes that normally operate in the mouse germline with those induced by the potent mutagen N-ethyl-N-nitrosourea (ENU). The considerable overlap in the mutation spectra of these two samples make this a challenging problem. Employing a new, robust log-linear modeling method, we demonstrate that neighboring bases contain information regarding point mutation direction that differs between the ENU-induced and spontaneous mutation variant classes. A logistic regression classifier exhibited strong performance at discriminating between the different mutation classes. Concordance between the feature set of the best classifier and information content analyses suggest our results can be generalized to other mutation classification problems. We conclude that machine learning can be used to build a practical classification tool to identify the mutation mechanism for individual genetic variants. Software implementing our approach is freely available under an open-source license.




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Porphyromonas gingivalis Cell Wall Components Induce Programmed Death Ligand 1 (PD-L1) Expression on Human Oral Carcinoma Cells by a Receptor-Interacting Protein Kinase 2 (RIP2)-Dependent Mechanism [Cellular Microbiology: Pathogen-Host Cell Molecular Inte

Programmed death-ligand 1 (PD-L1/B7-H1) serves as a cosignaling molecule in cell-mediated immune responses and contributes to chronicity of inflammation and the escape of tumor cells from immunosurveillance. Here, we investigated the molecular mechanisms leading to PD-L1 upregulation in human oral carcinoma cells and in primary human gingival keratinocytes in response to infection with Porphyromonas gingivalis (P. gingivalis), a keystone pathogen for the development of periodontitis. The bacterial cell wall component peptidoglycan uses bacterial outer membrane vesicles to be taken up by cells. Internalized peptidoglycan triggers cytosolic receptors to induce PD-L1 expression in a myeloid differentiation primary response 88 (Myd88)-independent and receptor-interacting serine/threonine-protein kinase 2 (RIP2)-dependent fashion. Interference with the kinase activity of RIP2 or mitogen-activated protein (MAP) kinases interferes with inducible PD-L1 expression.




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Interleukin-1 Receptor-Associated Kinase (IRAK) Signaling in Kaposi Sarcoma-Associated Herpesvirus-Induced Primary Effusion Lymphoma [Virus-Cell Interactions]

Kaposi sarcoma-associated herpesvirus (KSHV) is necessary but not sufficient for primary effusion lymphoma (PEL) development. Alterations in cellular signaling pathways are also a characteristic of PEL. Other B cell lymphomas have acquired an oncogenic mutation in the myeloid differentiation primary response 88 (MYD88) gene. The MYD88 L265P mutant results in the activation of interleukin-1 receptor associated kinase (IRAK). To probe IRAK/MYD88 signaling in PEL, we employed CRISPR/Cas9 technology to generate stable deletion clones in BCBL-1Cas9 and BC-1Cas9 cells. To look for off-target effects, we determined the complete exome of the BCBL-1Cas9 and BC-1Cas9 cells. Deletion of either MYD88, IRAK4, or IRAK1 abolished interleukin-1 beta (IL-1β) signaling; however, we were able to grow stable subclones from each population. Transcriptome sequencing (RNA-seq) analysis of IRAK4 knockout cell lines (IRAK4 KOs) showed that the IRAK pathway induced cellular signals constitutively, independent of IL-1β stimulation, which was abrogated by deletion of IRAK4. Transient complementation with IRAK1 increased NF-B activity in MYD88 KO, IRAK1 KO, and IRAK4 KO cells even in the absence of IL-1β. IL-10, a hallmark of PEL, was dependent on the IRAK pathway, as IRAK4 KOs showed reduced IL-10 levels. We surmise that, unlike B cell receptor (BCR) signaling, MYD88/IRAK signaling is constitutively active in PEL, but that under cell culture conditions, PEL rapidly became independent of this pathway.

IMPORTANCE One hundred percent of primary effusion lymphoma (PEL) cases are associated with Kaposi sarcoma-associated herpesvirus (KSHV). PEL cell lines, such as BCBL-1, are the workhorse for understanding this human oncovirus and the host pathways that KSHV dysregulates. Understanding their function is important for developing new therapies as well as identifying high-risk patient groups. The myeloid differentiation primary response 88 (MYD88)/interleukin-1 receptor associated kinase (IRAK) pathway, which has progrowth functions in other B cell lymphomas, has not been fully explored in PEL. By performing CRISPR/Cas9 knockout (KO) studies targeting the IRAK pathway in PEL, we were able to determine that established PEL cell lines can circumvent the loss of IRAK1, IRAK4, and MYD88; however, the deletion clones are deficient in interleukin-10 (IL-10) production. Since IL-10 suppresses T cell function, this suggests that the IRAK pathway may serve a function in vivo and during early-stage development of PEL.




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PIWIL4 Maintains HIV-1 Latency by Enforcing Epigenetically Suppressive Modifications on the 5' Long Terminal Repeat [Virus-Cell Interactions]

Although substantial progress has been made in depicting the molecular pathogenesis of human immunodeficiency virus type 1 (HIV-1) infection, the comprehensive mechanism of HIV-1 latency and the most promising therapeutic strategies to effectively reactivate the HIV-1 latent reservoir to achieve a functional cure for AIDS remain to be systematically illuminated. Here, we demonstrated that piwi (P element-induced Wimpy)-like RNA-mediated gene silencing 4 (PIWIL4) played an important role in suppressing HIV-1 transcription and contributed to the latency state in HIV-1-infected cells through its recruitment of various suppressive factors, including heterochromatin protein 1α/β/, SETDB1, and HDAC4. The knockdown of PIWIL4 enhanced HIV-1 transcription and reversed HIV-1 latency in both HIV-1 latently infected Jurkat T cells and primary CD4+ T lymphocytes and resting CD4+ T lymphocytes from HIV-1-infected individuals on suppressive combined antiretroviral therapy (cART). Furthermore, in the absence of PIWIL4, HIV-1 latently infected Jurkat T cells were more sensitive to reactivation with vorinostat (suberoylanilide hydroxamic acid, or SAHA), JQ1, or prostratin. These findings indicated that PIWIL4 promotes HIV-1 latency by imposing repressive marks at the HIV-1 5' long terminal repeat. Thus, the manipulation of PIWIL4 could be a novel strategy for developing promising latency-reversing agents (LRAs).

IMPORTANCE HIV-1 latency is systematically modulated by host factors and viral proteins. During this process, the suppression of HIV-1 transcription plays an essential role in promoting HIV-1 latency. In this study, we found that PIWIL4 repressed HIV-1 promoter activity and maintained HIV-1 latency. In particular, we report that PIWIL4 can regulate gene expression through its association with the suppressive activity of HDAC4. Therefore, we have identified a new function for PIWIL4: it is not only a suppressor of endogenous retrotransposons but also plays an important role in inhibiting transcription and leading to latent infection of HIV-1, a well-known exogenous retrovirus. Our results also indicate a novel therapeutic target to reactivate the HIV-1 latent reservoir.




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Glycoprotein 5 Is Cleaved by Cathepsin E during Porcine Reproductive and Respiratory Syndrome Virus Membrane Fusion [Virus-Cell Interactions]

Porcine reproductive and respiratory syndrome (PRRS) is a serious viral disease affecting the global swine industry. Its causative agent, PRRS virus (PRRSV), is an enveloped virus, and therefore membrane fusion between its envelope and host cell target membrane is critical for viral infection. Though much research has focused on PRRSV infection, the detailed mechanisms involved in its membrane fusion remain to be elucidated. In the present study, we performed confocal microscopy in combination with a constitutively active (CA) or dominant negative (DN) mutant, specific inhibitors, and small interfering RNAs (siRNAs), as well as multiple other approaches, to explore PRRSV membrane fusion. We first observed that PRRSV membrane fusion occurred in Rab11-recycling endosomes during early infection using labeled virions and subcellular markers. We further demonstrated that low pH and cathepsin E in Rab11-recycling endosomes are critical for PRRSV membrane fusion. Moreover, PRRSV glycoprotein 5 (GP5) is identified as being cleaved by cathepsin E during this process. Taken together, our findings provide in-depth information regarding PRRSV pathogenesis, which support a novel basis for the development of antiviral drugs and vaccines.

IMPORTANCE PRRS, caused by PRRSV, is an economically critical factor in pig farming worldwide. As PRRSV is a lipid membrane-wrapped virus, merging of the PRRSV envelope with the host cell membrane is indispensable for viral infection. However, there is a lack of knowledge on its membrane fusion. Here, we first explored when and where PRRSV membrane fusion occurs. Furthermore, we determined which host cell factors were involved in the process. Importantly, PRRSV GP5 is shown to be cleaved by cathepsin E during membrane fusion. Our work not only provides information on PRRSV membrane fusion for the first time but also deepens our understanding of the molecular mechanisms of PRRSV infection, which provides a foundation for future applications in the prevention and control of PRRS.




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Experimental Evolution To Isolate Vaccinia Virus Adaptive G9 Mutants That Overcome Membrane Fusion Inhibition via the Vaccinia Virus A56/K2 Protein Complex [Virus-Cell Interactions]

For cell entry, vaccinia virus requires fusion with the host membrane via a viral fusion complex of 11 proteins, but the mechanism remains unclear. It was shown previously that the viral proteins A56 and K2 are expressed on infected cells to prevent superinfection by extracellular vaccinia virus through binding to two components of the viral fusion complex (G9 and A16), thereby inhibiting membrane fusion. To investigate how the A56/K2 complex inhibits membrane fusion, we performed experimental evolutionary analyses by repeatedly passaging vaccinia virus in HeLa cells overexpressing the A56 and K2 proteins to isolate adaptive mutant viruses. Genome sequencing of adaptive mutants revealed that they had accumulated a unique G9R open reading frame (ORF) mutation, resulting in a single His44Tyr amino acid change. We engineered a recombinant vaccinia virus to express the G9H44Y mutant protein, and it readily infected HeLa-A56/K2 cells. Moreover, similar to the A56 virus, the G9H44Y mutant virus on HeLa cells had a cell fusion phenotype, indicating that G9H44Y-mediated membrane fusion was less prone to inhibition by A56/K2. Coimmunoprecipitation experiments demonstrated that the G9H44Y protein bound to A56/K2 at neutral pH, suggesting that the H44Y mutation did not eliminate the binding of G9 to A56/K2. Interestingly, upon acid treatment to inactivate A56/K2-mediated fusion inhibition, the G9H44Y mutant virus induced robust cell-cell fusion at pH 6, unlike the pH 4.7 required for control and revertant vaccinia viruses. Thus, A56/K2 fusion suppression mainly targets the G9 protein. Moreover, the G9H44Y mutant protein escapes A56/K2-mediated membrane fusion inhibition most likely because it mimics an acid-induced intermediate conformation more prone to membrane fusion.

IMPORTANCE It remains unclear how the multiprotein entry fusion complex of vaccinia virus mediates membrane fusion. Moreover, vaccinia virus contains fusion suppressor proteins to prevent the aberrant activation of this multiprotein complex. Here, we used experimental evolution to identify adaptive mutant viruses that overcome membrane fusion inhibition mediated by the A56/K2 protein complex. We show that the H44Y mutation of the G9 protein is sufficient to overcome A56/K2-mediated membrane fusion inhibition. Treatment of virus-infected cells at different pHs indicated that the H44Y mutation lowers the threshold of fusion inhibition by A56/K2. Our study provides evidence that A56/K2 inhibits the viral fusion complex via the latter’s G9 subcomponent. Although the G9H44Y mutant protein still binds to A56/K2 at neutral pH, it is less dependent on low pH for fusion activation, implying that it may adopt a subtle conformational change that mimics a structural intermediate induced by low pH.




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Mutations Near the N Terminus of Vaccinia Virus G9 Protein Overcome Restrictions on Cell Entry and Syncytium Formation Imposed by the A56/K2 Fusion Regulatory Complex [Virus-Cell Interactions]

The entry/fusion complex (EFC) consists of 11 conserved proteins embedded in the membrane envelope of mature poxvirus particles. Poxviruses also encode proteins that localize in cell membranes and negatively regulate superinfection and syncytium formation. The vaccinia virus (VACV) A56/K2 fusion regulatory complex associates with the G9/A16 EFC subcomplex, but functional support for the importance of this interaction was lacking. Here, we describe serially passaging VACV in nonpermissive cells expressing A56/K2 as an unbiased approach to isolate and analyze escape mutants. Viruses forming large plaques in A56/K2 cells increased in successive rounds of infection, indicating the occurrence and enrichment of adaptive mutations. Sequencing of genomes of passaged and cloned viruses revealed mutations near the N terminus of the G9 open reading frame but none in A16 or other genes. The most frequent mutation was His to Tyr at amino acid 44; additional escape mutants had a His-to-Arg mutation at amino acid 44 or a duplication of amino acids 26 to 39. An adaptive Tyr-to-Cys substitution at amino acid 42 was discovered using error-prone PCR to generate additional mutations. Myristoylation of G9 was unaffected by the near-N-terminal mutations. The roles of the G9 mutations in enhancing plaque size were validated by homologous recombination. The mutants exhibited enhanced entry and spread in A56/K2 cells and induced syncytia at neutral pH in HeLa cells despite the expression of A56/K2. The data suggest that the mutations perturb the interaction of G9 with A56/K2, although some association was still detected in detergent-treated infected cell lysates.

IMPORTANCE The entry of enveloped viruses is achieved by the fusion of viral and cellular membranes, a critical step in infection that determines host range and provides targets for vaccines and therapeutics. Poxviruses encode an exceptionally large number of proteins comprising the entry/fusion complex (EFC), which enables infection of diverse cells. Vaccinia virus (VACV), the prototype member of the poxvirus family, also encodes the fusion regulatory proteins A56 and K2, which are displayed on the plasma membrane and may be beneficial by preventing reinfection and cell-cell fusion. Previous studies showed that A56/K2 interacts with the G9/A16 EFC subcomplex in detergent-treated cell extracts. Functional evidence for the importance of this interaction was obtained by serially passaging wild-type VACV in cells that are nonpermissive because of A56/K2 expression. VACV mutants with amino acid substitutions or duplications near the N terminus of G9 were enriched because of their ability to overcome the block to entry imposed by A56/K2.




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Procedural justice training reduces police use of force and complaints against officers [Social Sciences]

Existing research shows that distrust of the police is widespread and consequential for public safety. However, there is a shortage of interventions that demonstrably reduce negative police interactions with the communities they serve. A training program in Chicago attempted to encourage 8,480 officers to adopt procedural justice policing strategies. These...




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Reduced perceptual narrowing in synesthesia [Psychological and Cognitive Sciences]

Synesthesia is a neurologic trait in which specific inducers, such as sounds, automatically elicit additional idiosyncratic percepts, such as color (thus “colored hearing”). One explanation for this trait—and the one tested here—is that synesthesia results from unusually weak pruning of cortical synaptic hyperconnectivity during early perceptual development. We tested the...




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Extent of Fermi-surface reconstruction in the high-temperature superconductor HgBa2CuO4+{delta} [Physics]

High magnetic fields have revealed a surprisingly small Fermi surface in underdoped cuprates, possibly resulting from Fermi-surface reconstruction due to an order parameter that breaks translational symmetry of the crystal lattice. A crucial issue concerns the doping extent of such a state and its relationship to the principal pseudogap and...




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Reversal of hyperactive subthalamic circuits differentially mitigates pain hypersensitivity phenotypes in parkinsonian mice [Neuroscience]

Although pain is a prevalent nonmotor symptom in Parkinson’s disease (PD), it is undertreated, in part because of our limited understanding of the underlying mechanisms. Considering that the basal ganglia are implicated in pain sensation, and that their synaptic outputs are controlled by the subthalamic nucleus (STN), we hypothesized that...




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Metal ions confinement defines the architecture of G-quartet, G-quadruplex fibrils and their assembly into nematic tactoids [Chemistry]

G-quadruplex, assembled from a square array of guanine (G) molecules, is an important structure with crucial biological roles in vivo but also a versatile template for ordered functional materials. Although the understanding of G-quadruplex structures is the focus of numerous studies, little is known regarding the control of G-quartet stacking...




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NRF3-POMP-20S Proteasome Assembly Axis Promotes Cancer Development via Ubiquitin-Independent Proteolysis of p53 and Retinoblastoma Protein [Research Article]

Proteasomes are essential protease complexes that maintain cellular homeostasis, and aberrant proteasomal activity supports cancer development. The regulatory mechanisms and biological function of the ubiquitin-26S proteasome have been studied extensively, while those of the ubiquitin-independent 20S proteasome system remain obscure. Here, we show that the cap ’n’ collar (CNC) family transcription factor NRF3 specifically enhances 20S proteasome assembly in cancer cells and that 20S proteasomes contribute to colorectal cancer development through ubiquitin-independent proteolysis of the tumor suppressor p53 and retinoblastoma (Rb) proteins. The NRF3 gene is highly expressed in many cancer tissues and cell lines and is important for cancer cell growth. In cancer cells, NRF3 upregulates the assembly of the 20S proteasome by directly inducing the gene expression of the 20S proteasome maturation protein POMP. Interestingly, NRF3 knockdown not only increases p53 and Rb protein levels but also increases p53 activities for tumor suppression, including cell cycle arrest and induction of apoptosis. Furthermore, protein stability and cell viability assays using two distinct proteasome inhibitor anticancer drugs, the 20S proteasome inhibitor bortezomib and the ubiquitin-activating enzyme E1 inhibitor TAK-243, show that the upregulation of the NRF3-POMP axis leads to ubiquitin-independent proteolysis of p53 and Rb and to impaired sensitivity to bortezomib but not TAK-243. More importantly, the NRF3-POMP axis supports tumorigenesis and metastasis, with higher NRF3/POMP expression levels correlating with poor prognoses in patients with colorectal or rectal adenocarcinoma. These results suggest that the NRF3-POMP-20S proteasome assembly axis is significant for cancer development via ubiquitin-independent proteolysis of tumor suppressor proteins.




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Requirement of the Cep57-Cep63 Interaction for Proper Cep152 Recruitment and Centriole Duplication [Research Article]

Cep57 has been characterized as a component of a pericentriolar complex containing Cep63 and Cep152. Interestingly, Cep63 and Cep152 self-assemble into a pericentriolar cylindrical architecture, and this event is critical for the orderly recruitment of Plk4, a key regulator of centriole duplication. However, the way in which Cep57 interacts with the Cep63-Cep152 complex and contributes to the structure and function of Cep63-Cep152 self-assembly remains unknown. We demonstrate that Cep57 interacts with Cep63 through N-terminal motifs and associates with Cep152 via Cep63. Three-dimensional structured illumination microscopy (3D-SIM) analyses suggested that the Cep57-Cep63-Cep152 complex is concentrically arranged around a centriole in a Cep57-in and Cep152-out manner. Cep57 mutant cells defective in Cep63 binding exhibited improper Cep63 and Cep152 localization and impaired Sas6 recruitment for procentriole assembly, proving the significance of the Cep57-Cep63 interaction. Intriguingly, Cep63 fused to a microtubule (MT)-binding domain of Cep57 functioned in concert with Cep152 to assemble around stabilized MTs in vitro. Thus, Cep57 plays a key role in architecting the Cep63-Cep152 assembly around centriolar MTs and promoting centriole biogenesis. This study may offer a platform to investigate how the organization and function of the pericentriolar architecture are altered by disease-associated mutations found in the Cep57-Cep63-Cep152 complex.




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E2F6-Mediated Downregulation of MIR22HG Facilitates the Progression of Laryngocarcinoma by Targeting the miR-5000-3p/FBXW7 Axis [Research Article]

Recently, abundant evidence has clarified that long noncoding RNAs (lncRNAs) play an oncogenic or anticancer role in the tumorigenesis and development of diverse human cancers. Described as a crucial regulator in some cancers, MIR22HG has not yet been studied in laryngocarcinoma and therefore the underlying regulatory role of MIR22HG in laryngocarcinoma is worth detecting. In this study, MIR22HG expression in laryngocarcinoma cells was confirmed to be downregulated, and upregulated MIR22HG expression led to suppressive effects on laryngocarcinoma cell proliferation and migration. Molecular mechanism assays revealed that MIR22HG sponges miR-5000-3p in laryngocarcinoma cells. Besides, decreased expression of miR-5000-3p suppressed laryngocarcinoma cell proliferation and migration. Moreover, the FBXW7 gene was reported to be a downstream target gene of miR-5000-3p in laryngocarcinoma cells. More importantly, rescue assays verified that FBXW7 depletion or miR-5000-3p upregulation countervailed the repressive effects of MIR22HG overexpression on laryngocarcinoma progression. In addition, E2F6 was proved to be capable of inhibiting MIR22HG transcription in laryngocarcinoma cells. To sum up, E2F6-induced downregulation of MIR22HG promotes laryngocarcinoma progression through the miR-5000-3p/FBXW7 axis.




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AKT Regulates Mitotic Progression of Mammalian Cells by Phosphorylating MASTL, Leading to Protein Phosphatase 2A Inactivation [Research Article]

Microtubule-associated serine/threonine kinase like (MASTL), also known as Greatwall (Gwl) kinase, has an important role in the regulation of mitosis. By inhibiting protein phosphatase 2A (PP2A), it plays a crucial role in activating one of the most important mitotic kinases, known as cyclin-dependent kinase 1 (CDK1). MASTL has been seen to be upregulated in various types of cancers and is also involved in tumor recurrence. It is activated by CDK1 through phosphorylations in the activation/T-loop, but the complete mechanism of its activation is still unclear. Here, we report that AKT phosphorylates MASTL at residue T299, which plays a critical role in its activation. Our results suggest that AKT increases CDK1-mediated phosphorylation and hence the activity of MASTL, which, in turn, promotes mitotic progression through PP2A inhibition. We also show that the oncogenic potential of AKT is augmented by MASTL activation, since AKT-mediated proliferation in colorectal cell lines can be attenuated by inhibiting and/or silencing MASTL. In brief, we report that AKT plays an important role in the progression of mitosis in mammalian cells and that it does so through the phosphorylation and activation of MASTL.




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Determining the Bioenergetic Capacity for Fatty Acid Oxidation in the Mammalian Nervous System [Research Article]

The metabolic state of the brain can greatly impact neurologic function. Evidence of this includes the therapeutic benefit of a ketogenic diet in neurologic diseases, including epilepsy. However, brain lipid bioenergetics remain largely uncharacterized. The existence, capacity, and relevance of mitochondrial fatty acid β-oxidation (FAO) in the brain are highly controversial, with few genetic tools available to evaluate the question. We have provided evidence for the capacity of brain FAO using a pan-brain-specific conditional knockout (KO) mouse incapable of FAO due to the loss of carnitine palmitoyltransferase 2, the product of an obligate gene for FAO (CPT2B–/–). Loss of central nervous system (CNS) FAO did not result in gross neuroanatomical changes or systemic differences in metabolism. Loss of CPT2 in the brain did not result in robustly impaired behavior. We demonstrate by unbiased and targeted metabolomics that the mammalian brain oxidizes a substantial quantity of long-chain fatty acids in vitro and in vivo. Loss of CNS FAO results in robust accumulation of long-chain acylcarnitines in the brain, suggesting that the mammalian brain mobilizes fatty acids for their oxidation, irrespective of diet or metabolic state. Together, these data demonstrate that the mammalian brain oxidizes fatty acids under normal circumstances with little influence from or on peripheral tissues.




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Phages Actively Challenge Niche Communities in Antarctic Soils

ABSTRACT

By modulating the structure, diversity, and trophic outputs of microbial communities, phages play crucial roles in many biomes. In oligotrophic polar deserts, the effects of katabatic winds, constrained nutrients, and low water availability are known to limit microbial activity. Although phages may substantially govern trophic interactions in cold deserts, relatively little is known regarding the precise ecological mechanisms. Here, we provide the first evidence of widespread antiphage innate immunity in Antarctic environments using metagenomic sequence data from hypolith communities as model systems. In particular, immunity systems such as DISARM and BREX are shown to be dominant systems in these communities. Additionally, we show a direct correlation between the CRISPR-Cas adaptive immunity and the metavirome of hypolith communities, suggesting the existence of dynamic host-phage interactions. In addition to providing the first exploration of immune systems in cold deserts, our results suggest that phages actively challenge niche communities in Antarctic polar deserts. We provide evidence suggesting that the regulatory role played by phages in this system is an important determinant of bacterial host interactions in this environment.

IMPORTANCE In Antarctic environments, the combination of both abiotic and biotic stressors results in simple trophic levels dominated by microbiomes. Although the past two decades have revealed substantial insights regarding the diversity and structure of microbiomes, we lack mechanistic insights regarding community interactions and how phages may affect these. By providing the first evidence of widespread antiphage innate immunity, we shed light on phage-host dynamics in Antarctic niche communities. Our analyses reveal several antiphage defense systems, including DISARM and BREX, which appear to dominate in cold desert niche communities. In contrast, our analyses revealed that genes which encode antiphage adaptive immunity were underrepresented in these communities, suggesting lower infection frequencies in cold edaphic environments. We propose that by actively challenging niche communities, phages play crucial roles in the diversification of Antarctic communities.




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Dedicated Workforce Required to Support Large-Scale Practice Improvement

Background:

Facilitation is an effective approach for helping practices implement sustainable evidence-based practice improvements. Few studies examine the facilitation infrastructure and support needed for large-scale dissemination and implementation initiatives.

Methods:

The Agency for Health care Research and Quality funded 7 Cooperatives, each of which worked with over 200 primary care practices to rapidly disseminate and implement improvements in cardiovascular preventive care. The intervention target was to improve primary care practice capacity for quality initiative and the ABCS of cardiovascular disease prevention: aspirin in high-risk individuals, blood pressure control, cholesterol management, and smoking cessation. We identified the organizational elements and infrastructures Cooperatives used to support facilitators by reviewing facilitator logs, online diary data, semistructured interviews with facilitators, and fieldnotes from facilitator observations. We analyzed these data using a coding and sorting process.

Results:

Each Cooperative partnered with 2 to 16 organizations, piecing together 16 to 35 facilitators, often from other quality improvement projects. Quality assurance strategies included establishing initial and ongoing training, processes to support facilitators, and monitoring to assure consistency and quality. Cooperatives developed facilitator toolkits, implemented initiative-specific training, and developed processes for peer-to-peer learning and support.

Conclusions:

Supporting a large-scale facilitation workforce requires creating an infrastructure, including initial training, and ongoing support and monitoring, often borrowing from other ongoing initiatives. Facilitation that recognizes the need to support the vital integrating functions of primary care might be more efficient and effective than this fragmented approach to quality improvement.




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Successful Health Care Provider Strategies to Overcome Psychological Insulin Resistance in United States and Canada

Purpose:

To identify specific actions and characteristics of health care providers (HCPs) in the United States and Canada that influenced patients with type 2 diabetes who were initially reluctant to begin insulin.

Methods:

Patients from the United States (n = 120) and Canada (n = 74) were recruited via registry, announcements, and physician referrals to complete a 30-minute online survey based on interviews with patients and providers regarding specific HCP actions that contributed to the decision to begin insulin.

Results:

The most helpful HCP actions were patient-centered approaches to improve patients’ understanding of the injection process (ie, "My HCP walked me through the whole process of exactly how to take insulin" [helped moderately or a lot, United States: 79%; Canada: 83%]) and alleviate concerns ("My HCP encouraged me to contact his/her office immediately if I ran into any problems or had questions after starting insulin" [United States: 76%; Canada: 82%]). Actions that were the least helpful included referrals to other sources (ie, "HCP referred patient to a class to help learn more about insulin" [United States: 40%; Canada: 58%]).

Conclusions:

The study provides valuable insight that HCPs can use to help patients overcome psychological insulin resistance, which is a critical step in the design of effective intervention protocols.




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The glue produced by Drosophila melanogaster for pupa adhesion is universal [RESEARCH ARTICLE]

Flora Borne, Alexander Kovalev, Stanislav Gorb, and Virginie Courtier-Orgogozo

Insects produce a variety of adhesives for diverse functions such as locomotion, mating, and egg or pupal anchorage to substrates. Although they are important for the biology of organisms and potentially represent a great resource for developing new materials, insect adhesives have been little studied so far. Here, we examined the adhesive properties of the larval glue of Drosophila melanogaster. This glue is made of glycosylated proteins and allows the animal to adhere to a substrate during metamorphosis. We designed an adhesion test to measure the pull-off force required to detach a pupa from a substrate and to evaluate the contact area covered by the glue. We found that the pupa adheres with similar forces to a variety of substrates (with distinct roughness, hydrophilic and charge properties). We obtained an average pull-off force of 217 mN, corresponding to 15,500 times the weight of a pupa and an adhesion strength of 137–244 kPa. Surprisingly, the pull-off forces did not depend on the contact area. Our study paves the way for a genetic dissection of the components of D. melanogaster glue that confer its particular adhesive properties.




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Microclimate buffering and thermal tolerance across elevations in a tropical butterfly [RESEARCH ARTICLE]

Gabriela Montejo-Kovacevich, Simon H. Martin, Joana I. Meier, Caroline N. Bacquet, Monica Monllor, Chris D. Jiggins, and Nicola J. Nadeau

Microclimatic variability in tropical forests plays a key role in shaping species distributions and their ability to cope with environmental change, especially for ectotherms. Nonetheless, currently available climatic datasets lack data from the forest interior and, furthermore, our knowledge of thermal tolerance among tropical ectotherms is limited. We therefore studied natural variation in the microclimate experienced by tropical butterflies in the genus Heliconius across their Andean range in a single year. We found that the forest strongly buffers temperature and humidity in the understorey, especially in the lowlands, where temperatures are more extreme. There were systematic differences between our yearly records and macroclimate databases (WorldClim2), with lower interpolated minimum temperatures and maximum temperatures higher than expected. We then assessed thermal tolerance of 10 Heliconius butterfly species in the wild and found that populations at high elevations had significantly lower heat tolerance than those at lower elevations. However, when we reared populations of the widespread H. erato from high and low elevations in a common-garden environment, the difference in heat tolerance across elevations was reduced, indicating plasticity in this trait. Microclimate buffering is not currently captured in publicly available datasets, but could be crucial for enabling upland shifting of species sensitive to heat such as highland Heliconius. Plasticity in thermal tolerance may alleviate the effects of global warming on some widespread ectotherm species, but more research is needed to understand the long-term consequences of plasticity on populations and species.




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Body surface temperature responses to food restriction in wild and captive great tits [RESEARCH ARTICLE]

Lucy A. Winder, Stewart A. White, Andreas Nord, Barbara Helm, and Dominic J. McCafferty

During winter at temperate and high latitudes, the low ambient temperatures, limited food supplies and short foraging periods mean small passerines show behavioural, morphological and physiological adaptations to reduce the risk of facing energy shortages. Peripheral tissues vasoconstrict in low ambient temperatures to reduce heat loss and cold injury. Peripheral vasoconstriction has been observed with food restriction in captivity but has yet to be explored in free-ranging animals. We experimentally food restricted both wild and captive great tits (Parus major) during winter months and measured surface temperatures of the bill and eye region using thermal imaging, to investigate whether birds show rapid local heterothermic responses, which may reduce their thermoregulatory costs when facing a perceived imminent food shortage. Our results of a continuously filmed wild population showed that bill temperature was immediately reduced in response to food restriction compared with when food was available ad libitum, an apparent autonomic response. Such immediacy implies a ‘pre-emptive’ response before the bird experiences any shortfalls in energy reserves. We also demonstrate temporal variation in vasoconstriction of the bill, with bill temperature gradually rising throughout the food restriction after the initial drop. Eye-region temperature in the wild birds remained at similar levels throughout food restriction compared with unrestricted birds, possibly reflecting the need to maintain steady circulation to the central nervous and visual systems. Our findings provide evidence that birds selectively allow the bill to cool when a predictable food supply is suddenly disrupted, probably as a means of minimising depletion of body reserves for a perceived future shortage in energy.




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Experimental facilitation of heat loss affects work rate and innate immune function in a breeding passerine bird [RESEARCH ARTICLE]

Fredrik Andreasson, Arne Hegemann, Andreas Nord, and Jan-Ake Nilsson

The capacity to get rid of excess heat produced during hard work is a possible constraint on parental effort during reproduction [heat dissipation limit (HDL) theory]. We released hard-working blue tits (Cyanistes caeruleus) from this constraint by experimentally removing ventral plumage. We then assessed whether this changed their reproductive effort (feeding rate and nestling size) and levels of self-maintenance (change in body mass and innate immune function). Feather-clipped females reduced the number of feeding visits and increased levels of constitutive innate immunity compared with unclipped females but did not fledge smaller nestlings. Thus, they increased self-maintenance without compromising current reproductive output. In contrast, feather clipping did not affect the number of feeding visits or innate immune function in males, despite increased heat loss rate. Our results show that analyses of physiological parameters, such as constitutive innate immune function, can be important when trying to understand sources of variation in investment in self-maintenance versus reproductive effort and that risk of overheating can influence innate immune function during reproduction.




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Habituation of the cardiovascular response to restraint stress is inhibited by exposure to other stressor stimuli and exercise training [RESEARCH ARTICLE]

Ricardo Benini, Leandro A. Oliveira, Lucas Gomes-de-Souza, Bruno Rodrigues, and Carlos C. Crestani

This study evaluated the effect of exposure to either a chronic variable stress (CVS) protocol or social isolation, as well as treadmill exercise training, in the habituation of the cardiovascular response upon repeated exposure to restraint stress in rats. The habituation of the corticosterone response to repeated restraint stress was also evaluated. For this, animals were subjected to either acute or 10 daily sessions of 60 min of restraint stress. CVS and social isolation protocols lasted for 10 consecutive days, whereas treadmill training was performed for 1 h per day, 5 days per week for 8 weeks. We observed that the increase in serum corticosterone was reduced during both the stress and the recovery period of the 10th session of restraint. Habituation of the cardiovascular response was identified in terms of a faster return of heart rate to baseline values during the recovery period of the 10th session of restraint. The increase in blood pressure and the decrease in tail skin temperature were similar at the 1st and 10th session of restraint. Exposure to CVS, social isolation or treadmill exercise training inhibited the habituation of the restraint-evoked tachycardia. Additionally, CVS increased the blood pressure response at the 10th session of restraint, whereas social isolation enhanced both the tachycardia during the first session and the drop in skin temperature at the 10th session of restraint. Taken together, these findings provide new evidence that pathologies evoked by stress might be related to impairment in the habituation process to homotypic stressors.




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Reduced immune responsiveness contributes to winter energy conservation in an Arctic bird [RESEARCH ARTICLE]

Andreas Nord, Arne Hegemann, and Lars P. Folkow

Animals in seasonal environments must prudently manage energy expenditure to survive the winter. This may be achieved through reductions in the allocation of energy for various purposes (e.g. thermoregulation, locomotion, etc.). We studied whether such trade-offs also include suppression of the innate immune response, by subjecting captive male Svalbard ptarmigan (Lagopus muta hyperborea) to bacterial lipopolysaccharide (LPS) during exposure to either mild temperature (0°C) or cold snaps (acute exposure to –20°C), in constant winter darkness when birds were in energy-conserving mode, and in constant daylight in spring. The innate immune response was mostly unaffected by temperature. However, energy expenditure was below baseline when birds were immune challenged in winter, but significantly above baseline in spring. This suggests that the energetic component of the innate immune response was reduced in winter, possibly contributing to energy conservation. Immunological parameters decreased (agglutination, lysis, bacteriostatic capacity) or did not change (haptoglobin/PIT54) after the challenge, and behavioural modifications (anorexia, mass loss) were lengthy (9 days). While we did not study the mechanisms explaining these weak, or slow, responses, it is tempting to speculate they may reflect the consequences of having evolved in an environment where pathogen transmission rate is presumably low for most of the year. This is an important consideration if climate change and increased exploitation of the Arctic would alter pathogen communities at a pace outwith counter-adaption in wildlife.




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Consequences of being phenotypically mismatched with the environment: no evidence of oxidative stress in cold- and warm-acclimated birds facing a cold spell [RESEARCH ARTICLE]

Ana Gabriela Jimenez, Emily Cornelius Ruhs, Kailey J. Tobin, Katie N. Anderson, Audrey Le Pogam, Lyette Regimbald, and Francois Vezina

Seasonal changes in maximal thermogenic capacity (Msum) in wild black-capped chickadees suggests that adjustments in metabolic performance are slow and begin to take place before winter peaks. However, when mean minimal ambient temperature (Ta) reaches –10°C, the chickadee phenotype appears to provide enough spare capacity to endure days with colder Ta, down to –20°C or below. This suggests that birds could also maintain a higher antioxidant capacity as part of their cold-acclimated phenotype to deal with sudden decreases in temperature. Here, we tested how environmental mismatch affected oxidative stress by comparing cold-acclimated (–5°C) and transition (20°C) phenotypes in chickadees exposed to an acute 15°C drop in temperature with that of control individuals. We measured superoxide dismutase, catalase and glutathione peroxidase activities, as well as lipid peroxidation damage and antioxidant scavenging capacity in pectoralis muscle, brain, intestine and liver. We generally found differences between seasonal phenotypes and across tissues, but no differences with respect to an acute cold drop treatment. Our data suggest oxidative stress is closely matched to whole-animal physiology in cold-acclimated birds compared with transition birds, implying that changes to the oxidative stress system happen slowly.




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Temperature has a causal and plastic effect on timing of breeding in a small songbird [RESEARCH ARTICLE]

Irene Verhagen, Barbara M. Tomotani, Phillip Gienapp, and Marcel E. Visser

Phenotypic plasticity is an important mechanism by which an individual can adapt its seasonal timing to predictable, short-term environmental changes by using predictive cues. Identification of these cues is crucial to forecast the response of species to long-term environmental change and to study their potential to adapt. Individual great tits (Parus major) start reproduction early under warmer conditions in the wild, but whether this effect is causal is not well known. We housed 36 pairs of great tits in climate-controlled aviaries and 40 pairs in outdoor aviaries, where they bred under artificial contrasting temperature treatments or in semi-natural conditions, respectively, for two consecutive years, using birds from lines selected for early and late egg laying. We thus obtained laying dates in two different thermal environments for each female. Females bred earlier under warmer conditions in climate-controlled aviaries, but not in outdoor aviaries. The latter was inconsistent with laying dates from our wild population. Further, early selection line females initiated egg laying consistently ~9 days earlier than late selection line females in outdoor aviaries, but we found no difference in the degree of plasticity (i.e. the sensitivity to temperature) in laying date between selection lines. Because we found that temperature causally affects laying date, climate change will lead to earlier laying. This advancement is, however, unlikely to be sufficient, thereby leading to selection for earlier laying. Our results suggest that natural selection may lead to a change in mean phenotype, but not to a change in the sensitivity of laying dates to temperature.