bluuebunny/crossref_metadata_2025 huggingface dataset:
A Seed Mucilage-Degrading Fungus From the Rhizosphere Strengthens the Plant-Soil-Microbe Continuum and Potentially Regulates Root Nutrients of a Cold Desert Shrub
Authors: Hu Dandan , Baskin Jerry M. , Baskin Carol C. , Liu Rong , Yang Xuejun , Huang Zhenying
Published: February 2021

Seed mucilage plays important roles in the adaptation of desert plants to the stressful environment. Artemisia sphaerocephala is an important pioneer plant in the Central Asian cold desert, and it produces a large quantity of seed mucilage. Seed mucilage of A. sphaerocephala can be degraded by soil microbes, but it is unknown which microorganisms can degrade mucilage or how the mucilage-degrading microorganisms affect rhizosphere microbial communities or root nutrients. Here, mucilage-degrading microorganisms were isolated from the rhizosphere of A. sphaerocephala, were screened by incubation with mucilage stained with Congo red, and were identified by sequencing and phylogenetic analyses. Fungal-bacterial networks based on high-throughput sequencing of rhizosphere microbes were constructed to explore the seasonal dynamic of interactions between a mucilage-degrading microorganism and its closely related microorganisms. The structural equation model was used to analyze effects of the mucilage-degrading microorganism, rhizosphere fungal-bacterial communities, and soil physicochemical properties on root C and N. The fungus Phanerochaete chrysosporium was identified as a mucilage-degrading microorganism. Relative abundance of the mucilage-degrading fungus (MDF) was highest in May. Subnetworks showed that the abundance of fungi and bacteria closely related to the MDF also were highest in May. Interactions between the MDF and related fungi and bacteria were positive, which might enhance mucilage degradation. In addition, the MDF might regulate root C and N by affecting rhizosphere microbial community structure. Our results suggest that MDF from the rhizosphere strengthens the plant-soil-microbe continuum, thereby potentially regulating microbial interactions and root nutrients of A. sphaerocephala.

[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
Dickeya dianthicola Is Not Vectored by Two Common Insect Pests of Potato
Authors: Insinga Jonas K. , Alyokhin Andrei , Hao Jianjun , Ge Tongling , Marangoni Nayara Fabiola , Baron Alex
Published: February 2021

Dickeya dianthicola (Samson) is an important pathogen causing blackleg disease of potato. Previous work suggested that insects might vector species of Pectobacteriaceae between plants but no conclusive work has confirmed this. Green peach aphids (Myzus persicae Sulzer) and Colorado potato beetles (Leptinotarsa decemlineata Say) are aggressive potato pests and related to known vectors of several species of bacteria other than D. dianthicola. This study sought to determine whether these insects vector D. dianthicola for potato infection. Neither insect species showed olfactory discrimination based on the presence of infection in laboratory tests but beetles were repelled by uninfected foliage treated with 2,3-butanediol, a primary Dickeya metabolite. Beetle recruitment to plants was not affected by their infection status; however, aphids preferred uninfected foliage when conspecifics were present. In the laboratory, neither insect acquired or transmitted D. dianthicola through feeding. In the field, neither insect’s abundance was significantly correlated with disease spread. Overall, this study did not find indications that D. dianthicola is vectored by the tested insect species. Therefore, efforts to limit Dickeya spread should focus on sanitation, water management, and seed screening—not on the control of these insect species.

[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
Dimensional analysis of spring-wing systems reveals performance metrics for resonant flapping-wing flight
Authors: Lynch James , Gau Jeff , Sponberg Simon , Gravish Nick
Published: February 2021

Flapping-wing insects, birds and robots are thought to offset the high power cost of oscillatory wing motion by using elastic elements for energy storage and return. Insects possess highly resilient elastic regions in their flight anatomy that may enable high dynamic efficiency. However, recent experiments highlight losses due to damping in the insect thorax that could reduce the benefit of those elastic elements. We performed experiments on, and simulations of, a dynamically scaled robophysical flapping model with an elastic element and biologically relevant structural damping to elucidate the roles of body mechanics, aerodynamics and actuation in spring-wing energetics. We measured oscillatory flapping-wing dynamics and energetics subject to a range of actuation parameters, system inertia and spring elasticity. To generalize these results, we derive the non-dimensional spring-wing equation of motion and present variables that describe the resonance properties of flapping systems:
N
, a measure of the relative influence of inertia and aerodynamics, and

K
^

, the reduced stiffness. We show that internal damping scales with
N
, revealing that dynamic efficiency monotonically decreases with increasing
N
. Based on these results, we introduce a general framework for understanding the roles of internal damping, aerodynamic and inertial forces, and elastic structures within all spring-wing systems.
Climate change affected the spatio-temporal occurrence of disasters in China over the past five centuries
Authors: Yan Chuan , Tian Huidong , Wan Xinru , He Jinxing , Ren Guoyu , Büntgen Ulf , Stenseth Nils Chr. , Zhang Zhibin
Published: February 2021

Climate change may contribute to the spatio-temporal occurrence of disasters. Long-term studies of either homogeneous or heterogeneous responses of historical disasters to climate change are, however, limited by the quality and quantity of the available proxy data. Here we reconstruct spatio-temporal patterns of five types of disasters in China during the period AD 1368–1911. Our analyses of these time series reveal that warmer temperatures decreased the occurrence of disasters in the monsoon-affected parts of central-east China, but it increased the frequency and intensity of disasters along the boundary of arid and humid conditions in parts of southwest and northeast China, probably driven by the interplay among monsoon, westerlies, polar vortex and variation of temperature. Moreover, we show that drought and flood events had cascading effects on the occurrences of locust outbreaks, famine and human epidemics. Our findings suggest that climate can contribute to the spatio-temporal occurrence of disasters, and therefore may contribute to an improvement of China's regional to national risk management of future climate and environmental change.
The everyday acoustic environment and its association with human heart rate: evidence from real-world data logging with hearing aids and wearables
Authors: Christensen Jeppe H. , Saunders Gabrielle H. , Porsbo Michael , Pontoppidan Niels H.
Published: February 2021

We investigate the short-term association between multidimensional acoustic characteristics of everyday ambient sound and continuous mean heart rate. We used in-market data from hearing aid users who logged ambient acoustics via smartphone-connected hearing aids and continuous mean heart rate in 5 min intervals from their own wearables. We find that acoustic characteristics explain approximately 4% of the fluctuation in mean heart rate throughout the day. Specifically, increases in ambient sound pressure intensity are significantly related to increases in mean heart rate, corroborating prior laboratory and short-term real-world data. In addition, increases in ambient sound quality—that is, more favourable signal to noise ratios—are associated with decreases in mean heart rate. Our findings document a previously unrecognized mixed influence of everyday sounds on cardiovascular stress, and that the relationship is more complex than is seen from an examination of sound intensity alone. Thus, our findings highlight the relevance of ambient environmental sound in models of human ecophysiology.
A minimalist model for coevolving supply and drainage networks
Authors: Anand Shashank Kumar , Hooshyar Milad , Martin Nordbotten Jan , Porporato Amilcare
Published: February 2021

Numerous complex systems, both natural and artificial, are characterized by the presence of intertwined supply and/or drainage networks. Here, we present a minimalist model of such coevolving networks in a spatially continuous domain, where the obtained networks can be interpreted as a part of either the counter-flowing drainage or co-flowing supply and drainage mechanisms. The model consists of three coupled, nonlinear partial differential equations that describe spatial density patterns of input and output materials by modifying a mediating scalar field, on which supply and drainage networks are carved. In the two-dimensional case, the scalar field can be viewed as the elevation of a hypothetical landscape, of which supply and drainage networks are ridges and valleys, respectively. In the three-dimensional case, the scalar field serves the role of a chemical signal, according to which vascularization of the supply and drainage networks occurs above a critical ‘erosion’ strength. The steady-state solutions are presented as a function of non-dimensional channelization indices for both materials. The spatial patterns of the emerging networks are classified within the branched and congested extreme regimes, within which the resulting networks are characterized based on the absolute as well as the relative values of two non-dimensional indices.
pH-sensitive thiamethoxam nanoparticles based on bimodal mesoporous silica for improving insecticidal efficiency
Authors: Li Wenjing , Wang Qi , Zhang Fang , Shang Hui , Bai Shiyang , Sun Jihong
Published: February 2021

In this study, we synthesized pH-sensitive thiamethoxam-3-(2-aminoethylamino) propyl-bimodal mesoporous silica (P/Thi-NN-BMMs) nanoparticles (NPs). We used this bimodal mesoporous silica (BMMs) mesoporous material as a carrier based on the principle of free radical polymerization. The size of the P/Thi-NN-BMMs NPs was about 891.7 ± 4.9 nm, with a zeta potential of about −25.7 ± 2.5 mV. X-ray powder diffraction analysis, N
2
-sorption measurements and thermogravimetric analysis indicated that thiamethoxam (Thi) was loaded into the pores of the mesoporous structure and that the mesopore surface was coated with polyacrylic acid (PAA). The loading rate of P/Thi-NN-BMMs was about 25.2%. The controlled-release NPs had excellent anti-photolysis performance and storage stability. The NPs showed significant pH sensitivity, and the Thi release rate in pH 10.0 phosphate buffer was higher than those in pH 7.4 and pH 3.0 phosphate buffers. We described the sustained-release curves according to the Weibull model. The relative toxicity of P/Thi-NN-BMMs against peach aphid was 1.44 times that of commercial Thi. This provides a promising instrument for effective insect control and environment protection.
Group housing and social dominance hierarchy affect circadian activity patterns in mice
Authors: Robbers Yuri , Tersteeg Mayke M. H. , Meijer Johanna H. , Coomans Claudia P.
Published: February 2021

In this study, we investigated the effect of social environment on circadian patterns in activity by group housing either six male or six female mice together in a cage, under regular light–dark cycles. Based on the interactions among the animals, the social dominance rank of individual mice was quantitatively established by calculating Elo ratings. Our results indicated that, during our experiment, the social dominance hierarchy was rapidly established, stable yet complex, often showing more than one dominant mouse and several subordinate mice. Moreover, we found that especially dominant male mice, but not female mice, displayed a significantly higher fraction of their activity during daytime. This resulted in reduced rhythm amplitude in dominant males. After division into separate cages, male mice showed an enhancement of their 24 h rhythm, due to lower daytime activity. Recordings of several physiological parameters showed no evidence for reduced health as a potential consequence of reduced rhythm amplitude. For female mice, transfer to individual housing did not affect their daily activity pattern. We conclude that 24 h rhythms under light–dark cycles are influenced by the social environment in males but not in females, and lead to a decrement in behavioural rhythm amplitude that is larger in dominant mice.
Video game play is positively correlated with well-being
Authors: Johannes Niklas , Vuorre Matti , Przybylski Andrew K.
Published: February 2021

People have never played more video games, and many stakeholders are worried that this activity might be bad for players. So far, research has not had adequate data to test whether these worries are justified and if policymakers should act to regulate video game play time. We attempt to provide much-needed evidence with adequate data. Whereas previous research had to rely on self-reported play behaviour, we collaborated with two games companies, Electronic Arts and Nintendo of America, to obtain players' actual play behaviour. We surveyed players of
Plants
vs.
Zombies: Battle for Neighborville
and
Animal Crossing: New Horizons
for their well-being, motivations and need satisfaction during play, and merged their responses with telemetry data (i.e. logged game play). Contrary to many fears that excessive play time will lead to addiction and poor mental health, we found a small positive relation between game play and affective well-being. Need satisfaction and motivations during play did not interact with play time but were instead independently related to well-being. Our results advance the field in two important ways. First, we show that collaborations with industry partners can be done to high academic standards in an ethical and transparent fashion. Second, we deliver much-needed evidence to policymakers on the link between play and mental health.
Factorial design-assisted reversed phase-high performance liquid chromatography method for simultaneous determination of fluconazole, itraconazole and terbinafine
Authors: Roshdy Aya , Elmansi Heba , Shalan Shereen , El-Brashy Amina
Published: February 2021

A 2
3
full factorial design model was used for the development of a new high performance liquid chromatography method with UV detection to estimate three antifungal drugs simultaneously. Fluconazole (FLU), itraconazole (ITR) and terbinafine (TRH) are co-administered for severe fungal infections. They have been determined using MOS-1 Hypersil C
18
column and an isocratic eluent; methanol 95% and phosphate buffer 5% with 0.001% triethylamine. The pH was adjusted to 7, and the flow rate was 0.7 ml min
−1
. The three drugs were separated within less than 7 min at 210 nm. The developed method gave a linear response over 5–80 µg ml
−1
, 5–50 µg ml
−1
and 1–50 µg ml
−1
for FLU, ITR and TRH, respectively. It showed detection limits of 0.88, 0.29 and 0.20 µg ml
−1
and quantification limits of 2.66, 0.88 and 0.60 µg ml
−1
for the three drugs, respectively. The design of the experiment facilitated the optimization of different variables affecting the separation of the three drugs. The sensitivity of the designed method permitted the simultaneous estimation of ITR and TRH in spiked human plasma successfully.
Fractional power series and the method of dominant balances
Authors: Chapman C. J. , Wynn H. P.
Published: February 2021

This paper derives an explicit formula for a type of fractional power series, known as a Puiseux series, arising in a wide class of applied problems in the physical sciences and engineering. Detailed consideration is given to the gaps which occur in these series (lacunae); they are shown to be determined by a number-theoretic argument involving the greatest common divisor of a set of exponents appearing in the Newton polytope of the problem, and by two number-theoretic objects, called here Sylvester sets, which are complements of Frobenius sets. A key tool is Faà di Bruno’s formula for high derivatives, as implemented by Bell polynomials. Full account is taken of repeated roots, of arbitrary multiplicity, in the leading-order polynomial which determines a fractional-power expansion, namely the facet polynomial. For high multiplicity, the fractional powers are shown to have large denominators and contain irregularly spaced gaps. The orientation and methods of the paper are those of applications, but in a concluding section we draw attention to a more abstract approach, which is beyond the scope of the paper.
A delay equation model for the Atlantic Multidecadal Oscillation
Authors: Falkena Swinda K. J. , Quinn Courtney , Sieber Jan , Dijkstra Henk A.
Published: February 2021

A new technique to derive delay models from systems of partial differential equations, based on the Mori–Zwanzig (MZ) formalism, is used to derive a delay-difference equation model for the Atlantic Multidecadal Oscillation (AMO). The MZ formalism gives a rewriting of the original system of equations, which contains a memory term. This memory term can be related to a delay term in a resulting delay equation. Here, the technique is applied to an idealized, but spatially extended, model of the AMO. The resulting delay-difference model is of a different type than the delay differential model which has been used to describe the El Niño Southern Oscillation. In addition to this model, which can also be obtained by integration along characteristics, error terms for a smoothing approximation of the model have been derived from the MZ formalism. Our new method of deriving delay models from spatially extended models has a large potential to use delay models to study a range of climate variability phenomena.
Using spectral submanifolds for optimal mode selection in nonlinear model reduction
Authors: Buza Gergely , Jain Shobhit , Haller George
Published: February 2021

Model reduction of large nonlinear systems often involves the projection of the governing equations onto linear subspaces spanned by carefully selected modes. The criteria to select the modes relevant for reduction are usually problem-specific and heuristic. In this work, we propose a rigorous mode-selection criterion based on the recent theory of spectral submanifolds (SSMs), which facilitates a reliable projection of the governing nonlinear equations onto modal subspaces. SSMs are exact invariant manifolds in the phase space that act as nonlinear continuations of linear normal modes. Our criterion identifies critical linear normal modes whose associated SSMs have locally the largest curvature. These modes should then be included in any projection-based model reduction as they are the most sensitive to nonlinearities. To make this mode selection automatic, we develop explicit formulae for the scalar curvature of an SSM and provide an open-source numerical implementation of our mode-selection procedure. We illustrate the power of this procedure by accurately reproducing the forced-response curves on three examples of varying complexity, including high-dimensional finite-element models.
Interaction between surface waves on wire lines
Authors: Molnar Daniel , Schaich Tobias , Al-Rawi Anas , Payne Mike
Published: February 2021

This paper investigates coupling between electromagnetic surface waves on parallel wires. Finite-element method (FEM)-based and analytic models are developed for single- and double-wire Sommerfeld and Goubau lines. Models are validated via measurements for Goubau lines and a comparison between the analytic and the FEM-based computations for coupled Sommerfeld- and Goubau-type lines is carried out. The measurements and calculations show remarkable agreement. The FEM-based and analytic models match remarkably well too. The results exhibit new favourable effects for surface waves propagation over multiple conductors. The short-range behaviour of the coupled wires and, consequently, the existence of an optimum separation of coupled wires is one of the most significant findings of this paper. We comment on the relevance of our results, particularly in relation to applications of high bandwidth demands and cross-coupling effects.
Construction of exact minimal parking garages: nonlinear helical motifs in optimally packed lamellar structures
Authors: da Silva Luiz C. B. , Efrati Efi
Published: February 2021

Minimal surfaces arise as energy minimizers for fluid membranes and are thus found in a variety of biological systems. The tight lamellar structures of the endoplasmic reticulum and plant thylakoids are comprised of such minimal surfaces in which right- and left-handed helical motifs are embedded in stoichiometry suggesting global pitch balance. So far, the analytical treatment of helical motifs in minimal surfaces was limited to the small-slope approximation where motifs are represented by the graph of harmonic functions. However, in most biologically and physically relevant regimes the inter-motif separation is comparable with its pitch, and thus this approximation fails. Here, we present a recipe for constructing exact minimal surfaces with an arbitrary distribution of helical motifs, showing that any harmonic graph can be deformed into a minimal surface by exploiting lateral displacements only. We analyse in detail pairs of motifs of the similar and of opposite handedness and also an infinite chain of identical motifs with similar or alternating handedness. Last, we study the second variation of the area functional for collections of helical motifs with asymptotic helicoidal structure and show that in this subclass of minimal surfaces stability requires that the collection of motifs is pitch balanced.
Tropical mammal functional diversity increases with productivity but decreases with anthropogenic disturbance
Authors: Gorczynski Daniel , Hsieh Chia , Luciano Jadelys Tonos , Ahumada Jorge , Espinosa Santiago , Johnson Steig , Rovero Francesco , Santos Fernanda , Andrianarisoa Mahandry Hugues , Astaiza Johanna Hurtado , Jansen Patrick A. , Kayijamahe Charles , Moreira Lima Marcela Guimarães , Salvador Julia , Beaudrot Lydia
Published: February 2021

A variety of factors can affect the biodiversity of tropical mammal communities, but their relative importance and directionality remain uncertain. Previous global investigations of mammal functional diversity have relied on range maps instead of observational data to determine community composition. We test the effects of species pools, habitat heterogeneity, primary productivity and human disturbance on the functional diversity (dispersion and richness) of mammal communities using the largest standardized tropical forest camera trap monitoring system, the Tropical Ecology Assessment and Monitoring (TEAM) Network. We use occupancy values derived from the camera trap data to calculate occupancy-weighted functional diversity and use Bayesian generalized linear regression to determine the effects of multiple predictors. Mammal community functional dispersion increased with primary productivity, while functional richness decreased with human-induced local extinctions and was significantly lower in Madagascar than other tropical regions. The significant positive relationship between functional dispersion and productivity was evident only when functional dispersion was weighted by species' occupancies. Thus, observational data from standardized monitoring can reveal the drivers of mammal communities in ways that are not readily apparent from range map-based studies. The positive association between occupancy-weighted functional dispersion of tropical forest mammal communities and primary productivity suggests that unique functional traits may be more beneficial in more productive ecosystems and may allow species to persist at higher abundances.
Group size increases inequality in cooperative behaviour
Authors: Rotics Shay , Clutton-Brock Tim
Published: February 2021

In cooperatively breeding species where rearing effort is shared among multiple group members, increases in group size typically reduce average per capita contributions to offspring care by all group members (load-lightening) but it is not known how changes in group size affect the distribution of workload among group members. The socioeconomic collective action theory suggests that, in larger groups, the incentives for free riding are stronger, leading to greater inequalities in work division among group members. Here, we use the Gini index to measure inequality at the group level in the contributions of helpers to three different cooperative behaviours (babysitting, pup-provisioning and raised guarding) in groups of varying size in wild Kalahari meerkats (Suricata suricatta). In larger groups, inequality in helpers' contributions to cooperative activities and the frequency of free riding both increased. Elevated levels of inequality were generated partly as a result of increased differences in contributions to cooperative activities between helpers in different sex and age categories in larger groups. After controlling for the positive effect of group size on total provisioning, increasing levels of inequality in contributions were associated with reductions in total pup-provisioning conducted by the group. Reductions in total pup-provisioning were, in turn, associated with reductions in the growth and survival of pups (but pup growth and survival were not directly affected by inequality in provisioning). Our results support the prediction of collective action theory described above and show how the Gini index can be used to investigate the distribution of cooperative behaviour within the group.
Investment in chemical signalling glands facilitates the evolution of sociality in lizards
Authors: Baeckens Simon , Whiting Martin J.
Published: February 2021

The evolution of sociality and traits that correlate with, or predict, sociality, have been the focus of considerable recent study. In order to reduce the social conflict that ultimately comes with group living, and foster social tolerance, individuals need reliable information about group members and potential rivals. Chemical signals are one such source of information and are widely used in many animal taxa, including lizards. Here, we take a phylogenetic comparative approach to test the hypothesis that social grouping correlates with investment in chemical signalling. We used the presence of epidermal glands as a proxy of chemical investment and considered social grouping as the occurrence of social groups containing both adults and juveniles. Based on a dataset of 911 lizard species, our models strongly supported correlated evolution between social grouping and chemical signalling glands. The rate of transition towards social grouping from a background of ‘epidermal glands present’ was an order of a magnitude higher than from a background of ‘no epidermal glands’. Our results highlight the potential importance of chemical signalling during the evolution of sociality and the need for more focused studies on the role of chemical communication in facilitating information transfer about individual and group identity, and ameliorating social conflict.
Non-numerical strategies used by bees to solve numerical cognition tasks
Authors: MaBouDi HaDi , Barron Andrew B. , Li Sun , Honkanen Maria , Loukola Olli J. , Peng Fei , Li Wenfeng , Marshall James A. R. , Cope Alex , Vasilaki Eleni , Solvi Cwyn
Published: February 2021

We examined how bees solve a visual discrimination task with stimuli commonly used in numerical cognition studies. Bees performed well on the task, but additional tests showed that they had learned continuous (non-numerical) cues. A network model using biologically plausible visual feature filtering and a simple associative rule was capable of learning the task using only continuous cues inherent in the training stimuli, with no numerical processing. This model was also able to reproduce behaviours that have been considered in other studies indicative of numerical cognition. Our results support the idea that a sense of magnitude may be more primitive and basic than a sense of number. Our findings highlight how problematic inadvertent continuous cues can be for studies of numerical cognition. This remains a deep issue within the field that requires increased vigilance and cleverness from the experimenter. We suggest ways of better assessing numerical cognition in non-speaking animals, including assessing the use of all alternative cues in one test, using cross-modal cues, analysing behavioural responses to detect underlying strategies, and finding the neural substrate.
After 15 years, no evidence for trophic cascades in marine protected areas
Authors: Malakhoff Katrina D. , Miller Robert J.
Published: February 2021

In marine ecosystems, fishing often targets predators, which can drive direct and indirect effects on entire food webs. Marine reserves can induce trophic cascades by increasing predator density and body size, thereby increasing predation pressure on populations of herbivores, such as sea urchins. In California's northern Channel Islands, two species of sea urchins are abundant: the red urchinMesocentrotus franciscanus, which is targeted by an economically valuable fishery, and the virtually unfished purple urchinStrongylocentrotus purpuratus. We hypothesized that urchin populations inside marine reserves would be depressed by higher predation, but that red urchins would be less affected due to fishing outside reserves. Instead, our analyses revealed that purple urchin populations were unaffected by reserves, and red urchin biomass significantly increased in response to protection. Therefore, urchin biomass overall has increased inside reserves, and we found no evidence that giant kelp is positively affected by reserves. Our results reveal the overwhelming direct effect of protecting fished species in marine reserves over indirect effects that are often predicted but seldom clearly documented. Indirect effects due to marine reserves may eventually occur in some cases, but very effective predators, large reserves or extended time periods may be needed to induce them.
Adaptation reduces competitive dominance and alters community assembly
Authors: Nadeau Christopher P. , Farkas Timothy E. , Makkay Andrea M. , Papke R. Thane , Urban Mark C.
Published: February 2021

A growing body of theory predicts that evolution of an early-arriving species in a new environment can produce a competitive advantage against later arriving species, therefore altering community assembly (i.e. the community monopolization hypothesis). Applications of the community monopolization hypothesis are increasing. However, experimental tests of the hypothesis are rare. Here, we provide a rare experimental demonstration of the community monopolization hypothesis using two archaeal species. We first expose one species to low- and high-temperature environments for 135 days. Populations in the high-temperature treatment evolved a 20% higher median performance when grown at high temperature. We then demonstrate that early arrival and adaptation reduce the abundance of a late-arriving species in the high-temperature environment by 63% relative to when both species arrive simultaneously and neither species is adapted to high temperature. These results are consistent with the community monopolization hypothesis and suggest that adaptation can reduce competitive dominance to alter community assembly. Hence, community monopolization might be much more common in nature than previously assumed. Our results strongly support the idea that patterns of biodiversity might often stem from a race between local adaptation and colonization of pre-adapted species.
Dietary-based developmental plasticity affects juvenile survival in an aquatic detritivore
Authors: Lürig Moritz D. , Matthews Blake
Published: February 2021

Developmental plasticity is ubiquitous in natural populations, but the underlying causes and fitness consequences are poorly understood. For consumers, nutritional variation of juvenile diets is probably associated with plasticity in developmental rates, but little is known about how diet quality can affect phenotypic trajectories in ways that might influence survival to maturity and lifetime reproductive output. Here, we tested how the diet quality of a freshwater detritivorous isopod (Asellus aquaticus), in terms of elemental ratios of diet (i.e. carbon : nitrogen : phosphorus; C : N : P), can affect (i) developmental rates of body size and pigmentation and (ii) variation in juvenile survival. We reared 1047 individuals, in a full-sib split-family design (29 families), on either a high- (low C : P, C : N) or low-quality (high C : P, C : N) diet, and quantified developmental trajectories of body size and pigmentation for every individual over 12 weeks. Our diet contrast caused strong divergence in the developmental rates of pigmentation but not growth, culminating in a distribution of adult pigmentation spanning the broad range of phenotypes observed both within and among natural populations. Under low-quality diet, we found highest survival at intermediate growth and pigmentation rates. By contrast, survival under high-quality diet survival increased continuously with pigmentation rate, with longest lifespans at intermediate growth rates and high pigmentation rates. Building on previous work which suggests that visual predation mediates the evolution of cryptic pigmentation inA. aquaticus, our study shows how diet quality and composition can generate substantial phenotypic variation by affecting rates of growth and pigmentation during development in the absence of predation.
Evidence for reduced immune gene diversity and activity during the evolution of termites
Authors: He Shulin , Sieksmeyer Thorben , Che Yanli , Mora M. Alejandra Esparza , Stiblik Petr , Banasiak Ronald , Harrison Mark C. , Šobotník Jan , Wang Zongqing , Johnston Paul R. , McMahon Dino P.
Published: February 2021

The evolution of biological complexity is associated with the emergence of bespoke immune systems that maintain and protect organism integrity. Unlike the well-studied immune systems of cells and individuals, little is known about the origins of immunity during the transition to eusociality, a major evolutionary transition comparable to the evolution of multicellular organisms from single-celled ancestors. We aimed to tackle this by characterizing the immune gene repertoire of 18 cockroach and termite species, spanning the spectrum of solitary, subsocial and eusocial lifestyles. We find that key transitions in termite sociality are correlated with immune gene family contractions. In cross-species comparisons of immune gene expression, we find evidence for a caste-specific social defence system in termites, which appears to operate at the expense of individual immune protection. Our study indicates that a major transition in organismal complexity may have entailed a fundamental reshaping of the immune system optimized for group over individual defence.
Sex-specific speed–accuracy trade-offs shape neural processing of acoustic signals in a grasshopper
Authors: Clemens Jan , Ronacher Bernhard , Reichert Michael S.
Published: February 2021

Speed–accuracy trade-offs—being fast at the risk of being wrong—are fundamental to many decisions and natural selection is expected to resolve these trade-offs according to the costs and benefits of behaviour. We here test the prediction that females and males should integrate information from courtship signals differently because they experience different pay-offs along the speed–accuracy continuum. We fitted a neural model of decision making (a drift–diffusion model of integration to threshold) to behavioural data from the grasshopperChorthippus biguttulusto determine the parameters of temporal integration of acoustic directional information used by male grasshoppers to locate receptive females. The model revealed that males had a low threshold for initiating a turning response, yet a large integration time constant enabled them to continue to gather information when cues were weak. This contrasts with parameters estimated for females of the same species when evaluating potential mates, in which response thresholds were much higher and behaviour was strongly influenced by unattractive stimuli. Our results reveal differences in neural integration consistent with the sex-specific costs of mate search: males often face competition and need to be fast, while females often pay high error costs and need to be deliberate.
Nonomuraea montanisoli sp. nov., isolated from mountain forest soil
Authors: Chanama Suchart , Suriyachadkun Chanwit , Chanama Manee
Published: February 2021

A novel actinomycete, strain SMC 257T, was isolated from a soil sample collected from mountain forest, Nan Province, Thailand. Strain SMC 257T formed tightly closed spiral spore chains on aerial mycelia. A polyphasic approach was used for the taxonomic study of this strain. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SMC 257T belonged to the genus

Nonomuraea

, and the closest phylogenetically related species were

Nonomuraea roseoviolacea

subsp.

carminata

JCM 9946T (98.9 % 16S rRNA gene sequence similarity),

Nonomuraea rhodomycinica

TBRC 6557T (98.4 %), and

Nonomuraea roseoviolacea

subsp.

roseoviolacea

JCM 3145T (98.3 %). Genome sequencing revealed a genome size of 9.76 Mbp and a G+C content of 72.3 mol%. The genome average nucleotide identity (ANI) and the digital DNA–DNA hybridization (dDDH) values that distinguished this novel strain from its closest related species were species boundary of 95–96 % and 70 %, respectively. The cell wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars were glucose, ribose, madurose and mannose. The major menaquinone was MK-9(H4). The polar lipid profile consisted of phosphatidylethanolamine, hydroxyphosphatidylethanolamine, lysophosphatidylethanolamine, diphosphatidylglycerol, N-phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides. The predominant cellular fatty acids were C17 : 0 10-methyl and iso-C16 : 0. Based on comparative analysis of phenotypic, chemotaxonomic and genotypic data, strain SMC 257T is considered to represent a novel species of the genus

Nonomuraea

, for which the name Nonomuraea montanisoli is proposed. The type strain is SMC 257T (=TBRC 13065T=NBRC 114772T).
Description of Sphingobium psychrophilum sp. nov., a cold-adapted bacterium isolated from Arctic soil
Authors: Dahal Ram Hari , Chaudhary Dhiraj Kumar , Kim Dong-Uk , Kim Jaisoo
Published: February 2021

A yellow-coloured, Gram-stain-negative, non-sporulating, psychrotolerant and motile bacterium, designated AR-3-1T, was isolated from the Arctic soil of Cambridge Bay, Nunavut, Canada. Strain AR-3-1T could grow at 4–32 °C and pH 5.0– 11.0. Phylogenetic analysis based on its 16S rRNA gene sequence indicated that strain AR-3-1T formed a lineage within the family

Sphingomonadaceae

and clustered as a member of the genus

Sphingobium

. The closest members within this genus were

Sphingobium cupriresistens

CU4T (98.1 % sequence similarity),

Sphingobium vermicomposti

VC-230T (97.6 %) and

Sphingobium lactosutens

DS20T (97.5 %). The only respiratory quinone was the ubiquinone Q-10. Spermidine was the predominant polyamine. The principal cellular fatty acids were summed feature 8 (C18 : 1
 ω7c and/or C18 : 1
 ω6c), summed feature 3 (iso-C15  : 0 2-OH and/or C16  : 1
ω7c), C16 : 0 and C14 : 0 2-OH. The major polar lipids were phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, sphingoglycolipid and phosphoglycolipid. The DNA G+C content was 63.1 %. The average nucleotide identity and in silico DNA–DNA hybridization relatedness values between strain AR-3-1T and its most closely related genus members were ≤89.6 and 39.6 %, respectively. The genome was 5 162 327 bp long, with 83 scaffolds and 4824 protein-coding genes. The genome showed six putative biosynthetic gene clusters responsible for various secondary metabolites. Based on this polyphasic study, strain AR-3-1T represents a novel species within the genus

Sphingobium

, for which the name Sphingobium psychrophilum sp. nov. is proposed. The type strain is AR-3-1T (=KACC 21613T=NBRC 114604T).
Transcriptome analysis of hepatoma cells transfected with Basal Core Promoter (BCP) and Pre-Core (PC) mutant hepatitis B virus full genome construct
Authors: Bhukya Prudhvi Lal , C. Vignesh Kumar , Lole Kavita S.
Published: February 2021

Infections with Basal Core Promoter (BCP) (A1762T/G1764A) and Pre-Core (PC) (G1896A) hepatitis B virus HBeAg mutants are associated with severe liver injury. We analysed host cell responses in HepG2/C3A, hepatoma cells transfected with infectious clones developed from genotype D wild type (WT) and BCP/PC mutant (MT) viruses isolated from an acute resolved and an acute liver failure hepatitis B case respectively. Cells transfected with MT virus construct showed ~55 % apoptosis and with WT ~30 % apoptosis at 72 h. To determine possible roles of HBe and HBx proteins in apoptosis, we cloned these genes and co-transfected cells with WT+HBe/HBx or MT+HBe/HBx constructs. Co-expression of HBe protein improved cell viability significantly in both WT and MT virus constructs, indicating an important role of HBe in protecting cells. RNA sequencing analysis carried out at 12 and 72 h post-transfection with WT virus construct showed enrichment of innate/adaptive immune response-activating signal transduction, cell survival and amino acid/nucleic acid biosynthetic pathways at 12 and 72 h. By contrast, MT virus construct showed enrichment in host defence pathways and some biosynthetic pathways at the early time point (12 h), and inflammatory response, secretary granule, regulation of membrane potential and stress response regulatory pathways at the late time point (72 h). There was a significant down-regulation of genes involved in endoplasmic reticulum and mitochondrial functions and metabolism with MT construct and this possibly led to induction of apoptosis in cells. Considering rapid apoptotic changes in cells transfected with MT construct, it can be speculated that HBeAg plays a crucial role in cell survival. It enhances induction of metabolic and synthetic pathways and facilitates management of cellular stress that is induced due to hepatitis B virus infection/replication.
Fidaxomicin has high in vitro activity against Mycobacterium tuberculosis
Authors: Sun Qing , Wang Shuqi , Liao Xinlei , Jiang Guanglu , Huang Hairong , Li Hao , Wang Guirong
Published: February 2021

This study aimed to evaluate whether the antibiotic fidaxomicin has in vitro activity against

Mycobacterium tuberculosis

(Mtb). 38 fully drug-sensitive Mtb strains and 34 multidrug-resistant tuberculosis (MDR-TB) strains were tested using the microplate alamar blue assay (MABA) method to determine the minimum inhibitory concentrations (MICs) for fidaxomicin and rifampicin. Fidaxomicin has high in vitro activity against Mtb and is a potential drug to treat Mtb, and MDR-TB infections in particular.
Pooled Surveillance Testing Program for Asymptomatic SARS-CoV-2 Infections in K-12 Schools and Universities
Authors: Bi Chongfeng , Mendoza Rachelle , Cheng Hui-Ting , Pagapas Gil , Gabutan Elmer , Khan Nadia , Hoxie Helen , Holmes Kelly , Gao Nicholas , Lewis Raychel , Wang Huaien , Neumann Daniel , Chan Angela , Takizawa Meril , Lowe James , Chen Xiao , Kelly Brianna , Asif Aneeza , Barnes Keena , Khan Nusrat , May Brandon , Wright Mecca , Chowdhury Tasnim , Pollonini Gabriella , Gouda Nourelhoda , Guy Chante , Gordon Candice , Ayoluwa Nana , Colon Elvin , Miller-Medzon Noah , Jones Shanique , Hossain Rauful , Dodson Arabia , Wang Meimei , McGaskey Miranda , Vasileva Ana , Seibel Sean , Connolly James , Esposito Michele , Kim Jane , Lincoln Andrew E. , Sikka Robby , Wyllie Anne L. , Berke Ethan M. , Libien Jenny , Pincus Matthew , Premsrirut Prem K.
Published: February 2021

The negative impact of continued school closures during the height of the COVID-19 pandemic warrants the establishment of new cost-effective strategies for surveillance and screening to safely reopen and monitor for potential in-school transmission. Here, we present a novel approach to increase the availability of repetitive and routine Covid-19 testing that may ultimately reduce the overall viral burden in the community. We describe implementation of a testing program that included students, faculty and staff from K-12 schools and universities participating in the SalivaClear™ pooled surveillance method (Mirimus Clinical Labs, Brooklyn, NY). Over 400,000 saliva specimens were self-collected from students, faculty and staff from 93 K-12 schools and 18 universities and tested in pools of up to 24 samples over a 20-week period during this pandemic. Peaks of positive cases were seen in the days following the Halloween, Thanksgiving and New Year holidays. Pooled testing did not significantly alter the sensitivity of the molecular assay in terms of both qualitative (100% detection rate on both pooled and individual samples) and quantitative (comparable cycle threshold (CT) values between pooled and individual samples) measures. Pooling samples substantially reduced the costs associated with PCR testing and allowed schools to rapidly assess transmission and adjust prevention protocols as necessary. By establishing low-cost, weekly testing of students and faculty, pooled saliva analysis enabled schools to determine whether transmission had occurred, make data-driven decisions, and adjust safety protocols. Pooled testing is a fundamental component to the reopening of schools, minimizing transmission among students and faculty.