bluuebunny/crossref_metadata_2025 huggingface dataset:
Single‐Molecule FRET of Membrane Transport Proteins
Authors: Bartels Kim , Lasitza‐Male Tanya , Hofmann Hagen , Löw Christian
Published: May 2021

Uncovering the structure and function of biomolecules is a fundamental goal in structural biology. Membrane‐embedded transport proteins are ubiquitous in all kingdoms of life. Despite structural flexibility, their mechanisms are typically studied by ensemble biochemical methods or by static high‐resolution structures, which complicate a detailed understanding of their dynamics. Here, we review the recent progress of single molecule Förster Resonance Energy Transfer (smFRET) in determining mechanisms and timescales of substrate transport across membranes. These studies do not only demonstrate the versatility and suitability of state‐of‐the‐art smFRET tools for studying membrane transport proteins but they also highlight the importance of membrane mimicking environments in preserving the function of these proteins. The current achievements advance our understanding of transport mechanisms and have the potential to facilitate future progress in drug design.
Mini‐patient‐derived xenograft assay based on microfluidic technology promises to be an effective tool for screening individualized chemotherapy regimens for advanced non‐small cell lung cancer
Authors: Wang Xue , Sun Yile , Xu Yunhua , Wen Danyi , An Na , Leng Xuejiao , Fu Guolong , Lu Shun , Chen Zhiwei
Published: May 2021

Patient‐derived xenograft (PDX) assay has been widely used in preclinical research in patients with multidrug‐resistant lung cancer. One hundred patients with non‐small cell lung cancer (NSCLC) were divided into MiniPDX group and conventional group, with 50 cases in each group. The MiniPDX assay was established by enriching high‐purity tumor cells using microfluidic technology to detect the drug sensitivity of NSCLC cells. All patients underwent conventional computed tomography (CT) scans of lung and mediastinum at baseline and during follow‐up. Kaplan–Meier method was used to compare the overall survival and progression‐free survival of two groups. The sensitivity of the same drug in different tumor xenograft varied greatly. The overall survival, progression‐free survival, and clinical benefit rate of patients in the MiniPDX‐guided chemotherapy group were significantly longer than those in the conventional chemotherapy group. MiniPDX assay may be an effective tool for screening chemotherapy regimens in NSCLC patients.
Novel reaction to new cystic fibrosis medication Trikafta
Authors: Stashower Julian , Carr Patrick , Miller Virginia , Zlotoff Barrett
Published: May 2021

We present a novel case of an urticaria multiforme‐type drug reaction to the new cystic fibrosis medication Trikafta (elexacaftor + tezacaftor + ivacaftor). Equipped with this information, clinicians may be more prepared to counsel and treat patients if they experience similar symptoms after beginning Trikafta.
Elucidating electrochemical intercalation mechanisms of biomass‐derived hard carbon in sodium‐/potassium‐ion batteries
Authors: Zhu Ziyi , Zhong Wentao , Zhang Yanjia , Dong Peng , Sun Shigang , Zhang Yingjie , Li Xue
Published: May 2021

Hard carbon materials are characterized by having rich resources, simple processing technology, and low cost, and they are promising as one of the anode electrodes for commercial applications of sodium‐/potassium‐ion batteries. Simultaneously, exploring the alkali metal ion storage mechanism is particularly important for designing high‐performance electrode materials. However, the structure of hard carbon is more complex, and the description of energy storage behavior is quite controversial. In this study, the Magnolia grandiflora Lima leaf is used as a precursor, combined with simple pyrolysis and impurity removal processes, to obtain biomass‐derived hard carbon material (carbonized Magnolia grandiflora Lima leaf [CMGL]). When it is used as an anode for sodium‐ion batteries, it exhibits a high specific capacity of 315 mAh/g, and the capacity retention rate is 90.0% after 100 cycles. For potassium‐ion batteries, the charge specific capacity is 263.5 mAh/g, with a capacity retention rate of 85.5% at the same cycling. Furthermore, different electrochemical analysis methods and microstructure characterization techniques were used to further elucidate the sodium/potassium storage mechanism of the material. All the results indicate that the high potential slope region represents the adsorption/desorption characteristics on the surface active sites, whereas the low‐potential quasiplateau region belongs to the ion insertion/extraction in the graphitic microcrystallites interlayer. It is noteworthy that potassium ion is randomly intercalated between the graphitic microcrystallite layer without forming a segmented intercalation compound structure.
Electrochemical Dehydrogenative C(sp2)−H Amination
Authors: Puthanveedu Mahesh , Khamraev Vladislav , Brieger Lukas , Strohmann Carsten , Antonchick Andrey P.
Published: May 2021

A transition‐metal‐free direct electrolytic C−H amination involving an electrochemically generated nitrenium ion intermediate has been developed. The electrosynthesis takes place in the absence of any organoiodine catalysts and is enabled by an in situ generated electrolyte. A novel, efficient intramolecular and intermolecular C−H amination has been demonstrated using a simple reaction setup.
Repurposing Anticancer Drugs To Tackle Malaria
Authors: Le Govic Yohann , Houzé Sandrine , Papon Nicolas
Published: May 2021

Despite considerable efforts, malaria remains one of the most devastating infectious disease worldwide. In the absence of an effective vaccine, the prophylaxis and management of Plasmodium infections still rely on the therapeutic use of antimalarial agents. However, the emergence of resistant parasites has jeopardized the efficiency of virtually all antimalarial drugs, including artemisinin combination therapies (ACTs). Thus, there is an urgent need for innovative treatments with novel targets to avoid or overcome drug resistance. In this context, Huang & colleagues prioritized compounds that can block the activity of epigenetic enzymes, and described the discovery of a selective P. falciparum histone deacetylase (HDAC) inhibitor with high activity against various stages of the parasite. These findings may pave the way toward developing new lead compounds with broad‐spectrum activity, thus facilitating malaria treatment and elimination.
Photoinduced Force Microscopy as an Efficient Method Towards the Detection of Nanoplastics
Authors: C. ten Have Iris , Duijndam Adriaan J. A. , Oord Ramon , van Berlo‐van den Broek Hannie J. M. , Vollmer Ina , Weckhuysen Bert M. , Meirer Florian
Published: May 2021

The degradation of plastic waste in aquatic environments, leading to plastic particles at the micro‐ and nanoscale is of growing concern. However, conventional analytical techniques either lack sufficient spatial resolution or the necessary spectroscopic means to investigate individual plastic nanoparticles. Both are however necessary to understand how macro‐ and micro‐sized plastic particles break down into nanometer‐sized particles. Here we show that a hybrid analytical technique, combining the spatial resolution of atomic force microscopy (AFM) with the chemical information from infrared (IR) spectroscopy, meets these requirements. We studied nanometer‐sized particles of polystyrene (PS), a plastic that is extensively used worldwide. We demonstrate that we can detect and quantify these so‐called nanoplastics down to 20 nm in size and discuss their physicochemical properties. We show that in saline aqueous environments, in the absence of light, oxidative degradation and chain scission are the main mechanisms to form and degrade PS micro‐ and nanoplastics.
Phase 1 trial of nelfinavir added to standard cisplatin chemotherapy with concurrent pelvic radiation for locally advanced cervical cancer
Authors: Garcia‐Soto Arlene E. , McKenzie Nathalie D. , Whicker Margaret E. , Pearson Joseph M. , Jimenez Edward A. , Portelance Lorraine , Hu Jennifer J. , Lucci Joseph A. , Qureshi Rehman , Kossenkov Andrew , Schwartz Lauren , Mills Gordon B. , Maity Amit , Lin Lilie L. , Simpkins Fiona
Published: May 2021

Background

Nelfinavir (NFV), an HIV‐1 protease inhibitor, has been shown to sensitize cancer cells to chemoradiation (CRT). The objectives of this phase 1 trial were to evaluate safety and identify the recommended phase 2 dose of NFV added to concurrent CRT for locally advanced cervical cancer.

Methods

Two dose levels of NFV were evaluated: 875 mg orally twice daily (dose level 1 [DL1]) and 1250 mg twice daily (DL2). NFV was initiated 7 days before CRT and continued through CRT completion. Toxicity, radiographic responses, and pathologic responses were evaluated. Serial tumor biopsies (baseline, after NFV monotherapy, on NFV + CRT, and posttreatment) were evaluated by immunohistochemistry, NanoString, and reverse‐phase‐protein‐array analyses.

Results

NFV sensitized cervical cancer cells to radiation, increasing apoptosis and tumor suppression in vivo. Patients (n = 13) with International Federation of Gynecology and Obstetrics stage IIA through IVA squamous cell cervical carcinoma were enrolled, including 7 patients at DL1 and 6 patients at DL2. At DL1, expansion to 6 patients was required after a patient developed a dose‐limiting toxicity, whereas no dose‐limiting toxicities occurred at DL2. Therefore, DL2 was established as the recommended phase 2 dose. All patients at DL2 completed CRT, and 1 of 6 experienced grade 3 or 4 anemia, nausea, and diarrhea. One recurrence was noted at DL2, with disease outside the radiation field. Ten of 11 evaluable patients remained without evidence of disease at a median follow‐up of 50 months. NFV significantly decreased phosphorylated Akt levels in tumors. Cell cycle and cancer pathways also were reduced by NFV and CRT.

Conclusions

NFV with CRT is well tolerated. The response rate is promising compared with historic controls in this patient population and warrants further investigation.
Consumption of sugar‐sweetened and artificially sweetened beverages and breast cancer survival
Authors: Farvid Maryam S. , Spence Nicholas D. , Rosner Bernard A. , Chen Wendy Y. , Eliassen A. Heather , Willett Walter C. , Holmes Michelle D.
Published: May 2021

Background

The activation of insulin pathways is hypothesized to promote tumor growth and worsen breast cancer survival. Sugar‐sweetened beverages (SSBs) can lead to a higher risk of insulin resistance and may affect survival. The authors prospectively evaluated the relation of postdiagnostic SSB and artificially sweetened beverage (ASB) consumption with mortality among women with breast cancer.

Methods

In total, 8863 women with stage I through III breast cancer were identified during follow‐up of the Nurses' Health Study (NHS; 1980‐2010) and Nurses' Health Study II (NHSII; 1991‐2011). Women completed a validated food frequency questionnaire every 4 years after diagnosis and were followed until death or the end of follow‐up (2014 for the NHS and 2015 for the NHSII). Multivariable Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of breast cancer‐specific and all‐cause mortality after adjusting for measures of adiposity and other potential predictors of cancer survival.

Results

With a median follow‐up of 11.5 years, 2482 deaths were prospectively documented, including 1050 deaths from breast cancer. Compared with women who had no consumption, women who had SSB consumption after diagnosis had higher breast cancer‐specific mortality (>1 to 3 servings per week: HR, 1.31 [95% CI, 1.09‐1.58]; >3 servings per week: HR, 1.35 [95% CI, 1.12‐1.62]; Ptrend = .001) and all‐cause mortality (>1 to 3 servings per week: HR, 1.21 [95% CI, 1.07‐1.37]; >3 servings per week: HR, 1.28 [95% CI, 1.13‐1.45]; Ptrend = .0001). In contrast, ASB consumption was not associated with higher breast cancer‐specific or all‐cause mortality. Furthermore, replacing 1 serving per day of SSB consumption with 1 serving per day of ASB consumption was not associated with a lower risk of mortality.

Conclusions

Higher postdiagnostic SSB consumption among breast cancer survivors was associated with higher breast cancer‐specific mortality and death from all causes.
Illumination estimation challenge: The experience of the first 2 years
Authors: Ershov Egor , Savchik Alex , Semenkov Ilya , Banić Nikola , Koščević Karlo , Subašić Marko , Belokopytov Alexander , Terekhin Arseniy , Senshina Daria , Nikonorov Artem , Li Zhihao , Qian Yanlin , Buzzelli Marco , Riva Riccardo , Bianco Simone , Schettini Raimondo , Barron Jonathan T. , Lončarić Sven , Nikolaev Dmitry
Published: May 2021

Illumination estimation is the essential step of computational color constancy, one of the core parts of various image processing pipelines of modern digital cameras. Having an accurate and reliable illumination estimation is important for reducing the illumination influence on the image colors. To motivate the generation of new ideas and the development of new algorithms in this field, two challenges on illumination estimation were conducted. The main advantage of testing a method on a challenge over testing it on some of the known datasets is the fact that the ground‐truth illuminations for the challenge test images are unknown up until the results have been submitted, which prevents any potential hyperparameter tuning that may be biased. The First illumination estimation challenge (IEC#1) had only a single task, global illumination estimation. The second illumination estimation challenge (IEC#2) was enriched with two additional tracks that encompassed indoor and two‐illuminant illumination estimation. Other main features of it are a new large dataset of images (about 5000) taken with the same camera sensor model, a manual markup accompanying each image, diverse content with scenes taken in numerous countries under a huge variety of illuminations extracted by using the SpyderCube calibration object, and a contest‐like markup for the images from the Cube++ dataset. This article focuses on the description of the past two challenges, algorithms which won in each track, and the conclusions that were drawn based on the results obtained during the first and second challenge that can be useful for similar future developments.
Hyperpolarization of cis‐15N2‐Azobenzene by Parahydrogen at Ultralow Magnetic Fields**
Authors: Sheberstov Kirill F. , Kozinenko Vitaly P. , Kiryutin Alexey S. , Vieth Hans‐Martin , Zimmermann Herbert , Ivanov Konstantin L. , Yurkovskaya Alexandra V.
Published: May 2021

The development of nuclear spins hyperpolarization, and the search for molecules that can be efficiently hyperpolarized is an active area in nuclear magnetic resonance. In this work we present a detailed study of SABRE SHEATH (signal amplification by reversible exchange in shield enabled alignment transfer to heteronuclei) experiments on 15N2‐azobenzene. In SABRE SHEATH experiments the nuclear spins of the target are hyperpolarized through transfer of spin polarization from parahydrogen at ultralow fields during a reversible chemical process. Azobenzene exists in two isomers, trans and cis. We show that all nuclear spins in cis‐azobenzene can be efficiently hyperpolarized by SABRE at suitable magnetic fields. Enhancement factors (relative to 9.4 T) reach up to 3000 for 15N spins and up to 30 for the 1H spins. We compare two approaches to observe either hyperpolarized magnetization of 15N/1H spins, or hyperpolarized singlet order of the 15N spin pair. The results presented here will be useful for further experiments in which hyperpolarized cis‐15N2‐azobenzene is switched by light to trans‐15N2‐azobenzene for storing the produced hyperpolarization in the long‐lived spin state of the 15N pair of trans‐15N2‐azobenzene.
Impedance Response of a Thin Film on an Electrode: Deciphering the Influence of the Double Layer Capacitance
Authors: Gharbi Oumaïma , Tran Mai T. T. , Orazem Mark E. , Tribollet Bernard , Turmine Mireille , Vivier Vincent
Published: May 2021

The different contributions of the interfacial capacitance are identified in the case of passive materials or thin protective coatings deposited on the electrode surface. The method is based on a graphical analysis of the EIS results to determine both the passive‐film capacitance in the high‐frequency domain and the double‐layer capacitance in the low‐frequency domain. The proposed analysis is shown to be independent of the physicochemical origins of the frequency dispersion of the interfacial capacitances which results, from an analysis point of view of the experimental results, in the use of a constant‐phase element However, for a correct evaluation of the thin‐film properties such as its thickness, the high‐frequency data must be corrected for the double‐layer contribution. In particular, it is shown that if the double‐layer capacitance gives a frequency‐dispersed response, it is necessary to correct the high‐frequency part for the double‐layer constant‐phase elements. This is first demonstrated on synthetic data and then used for the determination of the thickness of thin oxide film formed on Al in neutral pH solution.
Establishing Halogen‐Bond Preferences in Molecules with Multiple Acceptor Sites
Authors: Abeysekera Amila M. , Averkiev Boris B. , Sinha Abhijeet S. , Le Magueres Pierre , Aakeröy Christer B.
Published: May 2021

The interplay between hydrogen bonds (HBs) and halogen bonds (XBs), has been addressed by co‐crystallizing two halogen bond donors, 1,4‐diiodotetrafluorbenzene(DITFB) and 1,3,5‐trifluoro‐2,4,6‐triiodobenzene(TITFB) with four series of targets; N‐(pyridin‐2‐yl)benzamide (Bz‐X), N‐(pyridin‐2‐yl)picolinamides (2Pyr‐X), N‐(pyridin‐2‐yl)nicotinamides (3Pyr‐X), N‐(pyridin‐2‐yl)isonicotinamides (4Pyr‐X); X=H/Cl/Br/I. The structural outcomes were compared with interactions in the targets themselves. 13 co‐crystals were analysed by single‐crystal X‐ray diffraction (SCXRD). In all three co‐crystals from the 2Pyr series, the intramolecular HB remained intact while the XB donors engaged with the N(pyr) or O=C sites. In the ten co‐crystals from the other three series, the intermolecular HBs present in the individual targets were disrupted in 9/10 cases. Overall, the acceptor sites selected by the halogen‐bond donors in these targets were distributed as follows; N(pyr)=81 %, O=C (15 %) or π (4 %).
Moral injury, mental health and behavioural health outcomes: A systematic review of the literature
Authors: Hall Nicole A. , Everson Adam T. , Billingsley Madison R. , Miller Mary Beth
Published: May 2021

Despite a burgeoning of research on moral injury in the past decade, existing reviews have not explored the breadth of consequences and the multitude of pathways through which moral injury and potentially morally injurious experiences (PMIEs) influence mental and behavioural health outcomes. This study aimed to identify associations between moral injury on mental and behavioural health. Literature searches of psychological and medical databases were conducted through April 2020. Eligible studies measured moral injury or PMIEs, and health outcomes (e.g., depression, substance use and suicidality). Fifty‐seven publications representing 49 separate samples were included. Studies examined the impact of moral injury on post‐traumatic stress disorder (PTSD) (n = 43); depression (n = 32); anxiety (n = 15); suicide (n = 15); substance use (n = 14); and ‘other’ health outcomes, including pain, burnout, sleep disturbance and treatment‐seeking behaviours (n = 11). The majority of studies found significant positive associations between moral injury‐related constructs, mental health and behavioural health outcomes; however, the majority were also cross‐sectional and focused on military samples. Proposed mediators included lack of social support, negative cognitions and meaning‐making. Moderators included self‐compassion, pre‐deployment mental health education and mindfulness. Moral injury is associated with a variety of negative health outcomes. Research is needed to determine the mechanisms by which moral injury may influence these outcomes over time.
Oral manifestations of COVID‐19 patients: An online survey of the Egyptian population
Authors: El Kady Dina M. , Gomaa Esraa Ahmad , Abdella Walid Shaban , Ashraf Hussien Reham , Abd ElAziz Rawda H. , Khater Ahmad G. A.
Published: May 2021

Objectives

This pilot survey aims to study the oral manifestations associated with COVID‐19 infection and report the prevalence of oral signs and symptoms in COVID‐19 patients.

Materials and Methods

From May 15 to June 10, 2020, we used an online questionnaire containing the oral manifestations that are expected to be associated with the COVID‐19 infection. Adults in our survey who have been diagnosed with COVID‐19 positive were confirmed with reverse transcriptase PCR (RT‐PCR), and isolated in various hospitals in Cairo, Egypt.

Results

This pilot study included 58 (53.4% males and 46.6% females) COVID‐19 patients ages 18–46 years, and 13 (22.4%) were healthcare workers. Our results showed that 67.2% of the patients had at least one manifestation related to the oral cavity and salivary glands, and 32.8% (n = 19) did not have any symptoms associated with the oral cavity. The highest prevalence symptoms were dry mouth 39.7% (n = 23), gustatory dysfunction as 34.5% (n = 20) loss of salt sensation, 29.3% (n = 17) loss of sweet sensation, and 25.9% (n = 15) altered food taste, while the least prevalent symptoms were tongue redness 8.8% (n = 5), and gingival bleeding 7% (n = 4). The most frequently associated symptoms were loss of salt and sweetness, as reported by 27.6% of the participants. However, there was no significant association between the incidence of oral symptoms and demographic data (age, gender, or job) of the patients (p > 0.05).

Conclusions

Based on limited data, COVID‐19 significantly impacts the oral cavity and salivary glands, as salivary gland‐related symptoms and taste disorders are highly prevalent in COVID‐19 patients.
Conflict resolution in activist networks: Reflections on prework, power, and engaging with change in Appalachia
Authors: Romano Arthur , Linnemeier Emily K. , Allen Susan H.
Published: May 2021

This paper explores key lessons learned during the design and facilitation phases of a conflict resolution workshop with environmental activists in rural Appalachia. As these practice notes and analysis highlight, conflict resolution (CR) practitioners can support activists by engaging in robust preparation work in order to better understand how activists work together, how that work evolves over time, their frames for making sense of conflicts and new possibilities for collaboration. This work raises timely questions about the role of outside facilitator partiality in CR processes, especially when differences of power and marginalization within activist networks reveal fault lines that disrupt collaboration and trust.
Crystal‐storing histiocytes in ascites leading to a diagnosis of plasma cell myeloma
Authors: Hamadeh Fatima , Smith Mitchell R. , Hsi Eric D.
Published: May 2021

Histiocytes containing multiple needle‐shaped eosinophilic crystals visualized in a peritoneal fluid sample during evaluation of a patient for liver transplantation led to the diagnosis of unsuspected IgA kappa myeloma. Crystal‐storing histiocytosis is a rare phenomenon typically associated with multiple myeloma and B‐cell lymphoproliferative disorders. It can involve almost any anatomic site and can occasionally be seen in body fluid samples.
Habitat heterogeneity, temperature, and primary productivity drive elevational gradients in avian species diversity
Authors: Dillon Kristen G. , Conway Courtney J.
Published: May 2021

Aim

Anticipating and mitigating the impacts of climate change on species diversity in montane ecosystems requires a mechanistic understanding of drivers of current patterns of diversity. We documented the shape of elevational gradients in avian species richness in North America and tested a suite of a priori predictions for each of five mechanistic hypotheses to explain those patterns.

Location

United States

Methods

We used predicted occupancy maps generated from species distribution models for each of 646 breeding birds to document elevational patterns in avian species richness across the six largest U.S. mountain ranges. We used spatially explicit biotic and abiotic data to test five mechanistic hypotheses proposed to explain geographic variation in species richness.

Results

Elevational gradients in avian species richness followed a consistent pattern of low elevation plateau‐mid‐elevation peak (as per McCain, 2009). We found support for three of the five hypotheses to explain the underlying cause of this pattern: the habitat heterogeneity, temperature, and primary productivity hypotheses.

Main Conclusions

Species richness typically decreases with elevation, but the primary cause and precise shape of the relationship remain topics of debate. We used a novel approach to study the richness‐elevation relationship and our results are unique in that they show a consistent relationship between species richness and elevation among 6 mountain ranges, and universal support for three hypotheses proposed to explain the underlying cause of the observed relationship. Taken together, these results suggest that elevational variation in food availability may be the ecological process that best explains elevational gradients in avian species richness in North America. Although much attention has focused on the role of abiotic factors, particularly temperature, in limiting species’ ranges, our results offer compelling evidence that other processes also influence (and may better explain) elevational gradients in species richness.
Network analyses reveal the role of large snakes in connecting feeding guilds in a species‐rich Amazonian snake community
Authors: Pinto‐Coelho Daniela , Martins Marcio , Guimarães Junior Paulo Roberto
Published: May 2021

In ecological communities, interactions between consumers and resources lead to the emergence of ecological networks and a fundamental problem to solve is to understand which factors shape network structure. Empirical and theoretical studies on ecological networks suggest predator body size is a key factor structuring patterns of interaction. Because larger predators consume a wider resource range, including the prey consumed by smaller predators, we hypothesized that variation in body size favors the rise of nestedness. In contrast, if resource consumption requires specific adaptations, predators are expected to consume distinct sets of resources, thus favoring modularity. We investigate these predictions by characterizing the trophic network of a species‐rich Amazonian snake community (62 species). Our results revealed an intricate network pattern resulting from larger species feeding on higher diversity of prey and therefore promoting nestedness, whereas snakes with specific lifestyles and feeding on distinct resources, promoting modularity. Species removal simulations indicated that the nested structure is favored mainly by the presence of five species of the family Boidae, which because of their body size and generalist lifestyles connect modules in the network. Our study highlights the particular ways traits affect the structure of interactions among consumers and resources at the community level.
Evaluating new technology for biodiversity monitoring: Are drone surveys biased?
Authors: Corcoran Evangeline , Denman Simon , Hamilton Grant
Published: May 2021

Drones and machine learning‐based automated detection methods are being used by ecologists to conduct wildlife surveys with increasing frequency. When traditional survey methods have been evaluated, a range of factors have been found to influence detection probabilities, including individual differences among conspecific animals, which can thus introduce biases into survey counts. There has been no such evaluation of drone‐based surveys using automated detection in a natural setting. This is important to establish since any biases in counts made using these methods will need to be accounted for, to provide accurate data and improve decision‐making for threatened species. In this study, a rare opportunity to survey a ground‐truthed, individually marked population of 48 koalas in their natural habitat allowed for direct comparison of the factors impacting detection probability in both ground observation and drone surveys with manual and automated detection. We found that sex and host tree preferences impacted detection in ground surveys and in manual analysis of drone imagery with female koalas likely to be under‐represented, and koalas higher in taller trees detected less frequently when present. Tree species composition of a forest stand also impacted on detections. In contrast, none of these factors impacted on automated detection. This suggests that the combination of drone‐captured imagery and machine learning does not suffer from the same biases that affect conventional ground surveys. This provides further evidence that drones and machine learning are promising tools for gathering reliable detection data to better inform the management of threatened populations.
Population genetic structure of sharpbellyHemiculter leucisculus(Basilesky, 1855) and morphological diversification along climate gradients in China
Authors: Wang Lihong , Zhu Long , Tang Kui , Liu Mengyu , Xue Xue , Wang Gaoxue , Wang Zaizhao
Published: May 2021

SharpbellyHemiculter leucisculus(Basilewski, 1855) is a small, widespread, and native cyprinid fish with prominent habitat suitability and high invasive potential and is becoming the dominant species in freshwater ecosystems under intensified environmental disturbances. But howH. leucisculusacclimates to extremely heterogeneous environments remains unclear. In current study, the genetic structure ofH. leucisculuswas analyzed using Bayesian phylogenetic inference, haplotype network, and STRUCTURE base oncytbgene across 18 populations spanning 20 degrees of latitude and 18 degrees of longitude in China. The morphological diversification of body size and shape forH. leucisculusalong the climate gradient was studied. The results showed that the 18H. leucisculuspopulations were divided into 3 clusters: one cluster mainly from Huanghe River Basin, another cluster mainly from Yangzi River Basin, and H cluster containing Hainan and Beihai populations. The fish from southern populations were deeper bodied while individuals from northern populations were more slender. Inland individuals were more streamlined while coastal individuals were of deeper body. The partial Mantel test predicts that the potential mechanism underlining the intraspecies morphological diversification along climate gradients is primarily the divergent selection pressures among different environments, while genetic variation had less contribution to morphological differentiation. The formation of the Nanling Mountain Range could drive genetic differentiation between Beihai population and those from Yangzi River Basin. The present results highlight strong selective pressures of climate on widespread species and enrich morphological differentiation basis of acclimation for species with high habitat suitability and invasive potential.
Population differences in Chinook salmon (Oncorhynchus tshawytscha) DNA methylation: Genetic drift and environmental factors
Authors: Venney Clare J. , Sutherland Ben J. G. , Beacham Terry D. , Heath Daniel D.
Published: May 2021

Local adaptation and phenotypic differences among populations have been reported in many species, though most studies focus on either neutral or adaptive genetic differentiation. With the discovery of DNA methylation, questions have arisen about its contribution to individual variation in and among natural populations. Previous studies have identified differences in methylation among populations of organisms, although most to date have been in plants and model animal species. Here we obtained eyed eggs from eight populations of Chinook salmon (Oncorhynchus tshawytscha) and assayed DNA methylation at 23 genes involved in development, immune function, stress response, and metabolism using a gene‐targeted PCR‐based assay for next‐generation sequencing. Evidence for population differences in methylation was found at eight out of 23 gene loci after controlling for developmental timing in each individual. However, we found no correlation between freshwater environmental parameters and methylation variation among populations at those eight genes. A weak correlation was identified between pairwise DNA methylation dissimilarity among populations and pairwise FST based on 15 microsatellite loci, indicating weak effects of genetic drift or geographic distance on methylation. The weak correlation was primarily driven by two genes, GTIIBS and Nkef. However, single‐gene Mantel tests comparing methylation and pairwise FST were not significant after Bonferroni correction. Thus, population differences in DNA methylation are more likely related to unmeasured oceanic environmental conditions, local adaptation, and/or genetic drift. DNA methylation is an additional mechanism that contributes to among population variation, with potential influences on organism phenotype, adaptive potential, and population resilience.
Differential reliance on aquatic prey subsidies influences mercury exposure in riparian arachnids and songbirds
Authors: Jackson Allyson K. , Eagles‐Smith Collin A. , Robinson W. Douglas
Published: May 2021

Cross‐ecosystem subsidies move substantial amounts of nutrients between ecosystems. Emergent aquatic insects are a particularly important prey source for riparian songbirds but may also move aquatic contaminants, such as mercury (Hg), to riparian food webs. While many studies focus on species that eat primarily emergent aquatic insects, we instead study riparian songbirds with flexible foraging strategies, exploiting both aquatic and terrestrial prey sources. The goal in this study is to trace reliance on aquatic prey sources and correlate it to Hg concentrations in common riparian arachnids (Families Tetragnathidae, Opiliones, and Salticidae) and songbirds (Common Yellowthroat Geothlypis trichas, Spotted Towhee Pipilo maculatus, Swainson's Thrush Catharus ustulatus, Song Sparrow Melospiza melodia, and Yellow Warbler Setophaga petechia). We used stable isotopes of δ13C and δ15N and Bayesian mixing models in MixSIAR to determine the reliance of riparian predators on aquatic prey sources. Using mixed effects models, we found that arachnid families varied in their reliance on aquatic prey sources. While songbird species varied in their reliance on aquatic prey sources, songbirds sampled earlier in the season consistently relied more on aquatic prey sources than those sampled later in the season. For both arachnids and songbirds, we found a positive correlation between the amount of the aquatic prey source in their diet and their Hg concentrations. While the seasonal pulse of aquatic prey to terrestrial ecosystems is an important source of nutrients to riparian species, our results show that aquatic prey sources are linked with higher Hg exposure. For songbirds, reliance on aquatic prey sources early in the breeding season (and subsequent higher Hg exposure) coincides with timing of egg laying and development, both of which may be impacted by Hg exposure.
Six minutes to promote change: People, not facts, alter students' perceptions on climate change
Authors: Sauer Kodiak A. , Capps Daniel K. , Jackson David F. , Capps Krista A.
Published: May 2021

Anthropogenic climate change threatens the structure and function of ecosystems throughout the globe, but many people are still skeptical of its existence. Traditional “knowledge deficit model” thinking has suggested that providing the public with more facts about climate change will assuage skepticism. However, presenting evidence contrary to prior beliefs can have the opposite effect and result in a strengthening of previously held beliefs, a phenomenon known as biased assimilation or a backfire effect. Given this, strategies for effectively communicating about socioscientific issues that are politically controversial need to be thoroughly investigated. We randomly assigned 184 undergraduates from an environmental science class to one of three experimental conditions in which we exposed them to short videos that employed different messaging strategies: (a) an engaging science lecture, (b) consensus messaging, and (c) elite cues. We measured changes in student perceptions of climate change across five constructs (content knowledge, acceptance of scientific consensus, perceived risk, support for action, and climate identity) before and after viewing videos. Consensus messaging outperformed the other two conditions in increasing student acceptance of the scientific consensus, perceived risk of climate change, and climate identity, suggesting this may be an effective strategy for communicating the gravity of anthropogenic climate change. Elite cues outperformed the engaging science lecture condition in increasing student support for action on climate, with politically conservative students driving this relationship, suggesting that the messenger is more important than the message if changing opinions about the necessity of action on climate change is the desired outcome. Relative to the other conditions, the engaging science lecture did not support change in students' perceptions on climate, but appealing to student respect for authority produced positive results. Notably, we observed no decline in students' acceptance of climate science, indicating that none of the conditions induced a backfire effect.
Collecting eco‐evolutionary data in the dark: Impediments to subterranean research and how to overcome them
Authors: Mammola Stefano , Lunghi Enrico , Bilandžija Helena , Cardoso Pedro , Grimm Volker , Schmidt Susanne I. , Hesselberg Thomas , Martínez Alejandro
Published: May 2021

Caves and other subterranean habitats fulfill the requirements of experimental model systems to address general questions in ecology and evolution. Yet, the harsh working conditions of these environments and the uniqueness of the subterranean organisms have challenged most attempts to pursuit standardized research.

Two main obstacles have synergistically hampered previous attempts. First, there is ahabitat impedimentrelated to the objective difficulties of exploring subterranean habitats and our inability to access the network of fissures that represents the elective habitat for the so‐called “cave species.” Second, there is abiological impedimentillustrated by the rarity of most subterranean species and their low physiological tolerance, often limiting sample size and complicating laboratory experiments.

We explore the advantages and disadvantages of four general experimental setups (in situ,quasi in situ,ex situ, andin silico) in the light of habitat and biological impediments. We also discuss the potential of indirect approaches to research. Furthermore, using bibliometric data, we provide a quantitative overview of the model organisms that scientists have exploited in the study of subterranean life.

Our over‐arching goal is to promote caves as model systems where one can perform standardized scientific research. This is important not only to achieve an in‐depth understanding of the functioning of subterranean ecosystems but also to fully exploit their long‐discussed potential in addressing general scientific questions with implications beyond the boundaries of this discipline.
Processes underlying complex patterns of song trait evolution in a Setophaga hybrid zone
Authors: Love Jay , Goller Franz
Published: May 2021

During secondary contact between two species when hybrids are less fit than parents, mating signals are expected to diverge, while aggressive signals are expected to converge. If a single signal trait is used in both mating and aggression, then the dynamics between these two forces could influence the evolutionary trajectory of that trait. We studied such a situation in an avian hybrid zone between two Setophaga species, where birdsong is used in both mate attraction and territory defense. We hypothesized that song modules of the two species will show separate and distinct geographic patterns due to the influence of selective pressures for effective territorial aggression and for effective mate attraction. We conducted geographic cline analyses and playback experiments across this hybrid zone. We found an unexpected geographic pattern of asymmetric introgression of song rhythm, which may be explained by results of the playback experiments that suggest that differences in song rhythm serve a greater role in mate attraction than in territory defense. In contrast, differences in syllable morphology show little evidence of importance in mate attraction or territorial defense. Song features converge in the hybrid zone, yet patterns of trait change suggest that the song production modules may vary in their modes of development and inheritance. Syringeal motor gesturing, which gives rise to syllable morphology, shows a nonclinal mosaic pattern, suggesting that this trait may be predominantly learned. In contrast, respiratory patterning, which forms song rhythm, shows a clinal geographic transition, suggesting that this trait could be more innate. The results indicate that opposing forces act independently on song via distinct modules of the song production mechanism, driving complex patterns of song trait evolution.
Trait hierarchies are stronger than trait dissimilarities in structuring spatial co‐occurrence patterns of common tree species in a subtropical forest
Authors: Yin Deyi , Liu Yu , Ye Qing , Cadotte Marc W. , He Fangliang
Published: May 2021

The dissimilarity and hierarchy of trait values that characterize niche and fitness differences, respectively, have been increasingly applied to infer mechanisms driving community assembly and to explain species co‐occurrence patterns. Here, we predict that limiting similarity should result in the spatial segregation of functionally similar species, while functionally similar species will be more likely to co‐occur either due to environmental filtering or due to competitive exclusion of inferior competitors (hereafter hierarchical competition).

We used a fully mapped 50‐ha subtropical forest plot in southern China to explore how pairwise spatial associations between saplings and between adult trees were influenced by trait dissimilarity and hierarchy in order to gain insight into assembly mechanisms. We assessed pairwise spatial associations using two summary statistics of spatial point patterns at different spatial scales and compared the effects of trait dissimilarity and trait hierarchy of different functional traits on the interspecific spatial associations. These comparisons allow us to disentangle the effects of limiting similarity, environmental filtering, and hierarchical competition on species co‐occurrence.

We found that trait dissimilarity was generally negatively related to interspecific spatial associations for both saplings and adult trees across spatial scales, meaning that species with similar trait values were more likely to co‐occur and thus supporting environmental filtering or hierarchical competition. We further found that trait hierarchy outweighed trait dissimilarity in structuring pairwise spatial associations, suggesting that hierarchical competition played a more important role in structuring our forest community than environmental filtering across life stages.

This study employed a novel method, by offering the integration of pairwise spatial association and trait dissimilarity as well as trait hierarchy, to disentangle the relative importance of multiple assembly mechanisms in structuring co‐occurrence patterns, especially the mechanisms of environmental filtering and hierarchical competition, which lead to indistinguishable co‐occurrence patterns. This study also reinforced the importance of trait hierarchy rather than trait dissimilarity in driving neighborhood competition.
The mid‐domain effect and habitat complexity applied to elevational gradients: Moss species richness in a temperate semihumid monsoon climate mountain of China
Authors: Gao De , Fu Liqin , Sun Jiaxing , Li Yan , Cao Zhen , Liu Yongying , Xu Peng , Zhao Jiancheng
Published: May 2021

The utility of elevational gradients as tools to test either ecological hypotheses and delineate elevation‐associated environmental factors that explain the species diversity patterns is critical for moss species conservation. We examined the elevational patterns of species richness and evaluated the effects of spatial and environmental factors on moss species predicted a priori by alternative hypotheses, including mid‐domain effect (MDE), habitat complexity, energy, and environment proposed to explain the variation of diversity. Last, we assessed the contribution of elevation toward explaining the heterogeneity among sampling sites. We observed the hump‐shaped distribution pattern of species richness along elevational gradient. The MDE and the habitat complexity hypothesis were supported with MDE being the primary driver for richness patterns, whereas little support was found for the energy and the environmental factors.
Genetic differentiation and signatures of local adaptation revealed by RADseq for a highly dispersive mud crab Scylla olivacea (Herbst, 1796) in the Sulu Sea
Authors: Mendiola Michael John R. , Ravago‐Gotanco Rachel
Published: May 2021

Connectivity of marine populations is shaped by complex interactions between biological and physical processes across the seascape. The influence of environmental features on the genetic structure of populations has key implications for the dynamics and persistence of populations, and an understanding of spatial scales and patterns of connectivity is crucial for management and conservation. This study employed a seascape genomics approach combining larval dispersal modeling and population genomic analysis using single nucleotide polymorphisms (SNPs) obtained from RADseq to examine environmental factors influencing patterns of genetic structure and connectivity for a highly dispersive mud crab Scylla olivacea (Herbst, 1796) in the Sulu Sea. Dispersal simulations reveal widespread but asymmetric larval dispersal influenced by persistent southward and westward surface circulation features in the Sulu Sea. Despite potential for widespread dispersal across the Sulu Sea, significant genetic differentiation was detected among eight populations based on 1,655 SNPs (FST = 0.0057, p < .001) and a subset of 1,643 putatively neutral SNP markers (FST = 0.0042, p < .001). Oceanography influences genetic structure, with redundancy analysis (RDA) indicating significant contribution of asymmetric ocean currents to neutral genetic variation ( = 0.133, p = .035). Genetic structure may also reflect demographic factors, with divergent populations characterized by low effective population sizes (Ne < 50). Pronounced latitudinal genetic structure was recovered for loci putatively under selection (FST = 0.2390, p < .001), significantly correlated with sea surface temperature variabilities during peak spawning months for S. olivacea ( = 0.692–0.763; p < .050), suggesting putative signatures of selection and local adaptation to thermal clines. While oceanography and dispersal ability likely shape patterns of gene flow and genetic structure of S. olivacea across the Sulu Sea, the impacts of genetic drift and natural selection influenced by sea surface temperature also appear as likely drivers of population genetic structure. This study contributes to the growing body of literature documenting population genetic structure and local adaptation for highly dispersive marine species, and provides information useful for spatial management of the fishery resource.