Multiple Stressors Research Articles

Developing Adverse Outcome Pathways to support radioecological risk assessment: Challenges and insights.

Environmental pollution associated with long term effects, especially in the case of ionizing radiation, poses significant risks to wildlife, necessitating a more nuanced approach to Ecological Risk Assessment (ERA). In radioecology, current methods, as outlined by the International Commission on Radiological Protection (ICRP), focus primarily on exposure and individual/population-level effects, often both suffering a lack of ecological realism due to the nature of data used, and, sidelining a big amount of critical non-individual effects such as sub-individual one like genotoxicity. This review aims to address these gaps by suggesting the integration of New Approach Methods (NAMs) and the Adverse Outcome Pathway (AOP) framework in the field of radioecology. NAMs encompass innovative techniques, such as in silico and in vitro methodologies, that can provide predictive insights without relying solely on traditional animal testing. The AOP framework, developed by the Organization for Economic Cooperation and Development (OECD), structures effects data into a sequence of causally linked events, enabling a clearer understanding of how molecular changes lead to adverse ecological outcomes. In the first section of the review, we explore the challenges of applying AOPs within radioecology, including the complexities of modelling realistic exposure scenarios, the temporal dynamics of effects, and the impacts of multiple stressors. The second section highlights the potential and the application of some NAMs within an AOP framework to contribute improving risk assessment methodologies (in species realism issue and the use of sub-individual data). This part also offers other potential solutions to increase the number of data to be used in ERA as well as their ecological realism, through the use of AOP framework with relevant biological scales and ecological endpoints still uninvestigated in such way. In conclusion, leveraging NAMs and AOPs is much valuable for bridging molecular data and ecological implications, thereby advancing regulatory practices in radioecology and ensuring more comprehensive protection of ecosystems from radiological hazards.

Looking Back Looking Forward: Parent-Infant Treatment in the Anni Bergman Home-Visiting Project

ABSTRACT In this paper the authors describe the Anni Bergman Parent-Infant Program (ABPIP), with a focus on the development of the Home-Visiting Project (HVP) begun in 2014 in New York City. This primary prevention project provides psychoanalytic, relationship-based clinical intervention to mothers and their infants struggling with multiple stressors caused by poverty, histories of trauma, single parenthood, lack of employment, and limited access to health care and food. The beginnings of the project are described, including the centrality of infant observation as a port of entry into the subsequent dyadic therapy approach. Three clinical vignettes of the first mother-infant pair with whom we worked illustrate the beginnings of the treatment model that we developed. Both authors visited the mother and infant pair on a weekly basis for three years. Thinking and working together helped to create a template for the outreach project, the intervention approach, and informed further plans to expand the project and to include additional therapists and referral sources.

Prokaryotic and eukaryotic periphyton responses to warming, nutrient enrichment and small omnivorous fish: a shallow lake mesocosms experiment.

Global change stressors, including climate warming, eutrophication, and small-sized omnivorous fish, may exert interactive effects on the food webs and functioning of shallow lakes. Periphyton plays a central role in the primary production and nutrient cycling of shallow lakes but constitutes a complex community composed of eukaryotes and prokaryotes that may exhibit different responses to multiple environmental stressors with implications for the projections of the effects of global change on shallow lakes. We analyzed the effects of warming, nutrient enrichment, small omnivorous fish and their interactions on eukaryotic and prokaryotic periphyton structures in shallow lake mesocosms. We performed 16S and 18S rRNA high-throughput sequencing to elucidate the effect of the abovementioned stressors. We found that warming promoted periphytic alpha diversity and network complexity, with multi-tolerant genera becoming dominating (e.g. Spirosomaceae and Azospirillaceae). Contrastingly, nutrient enrichment led to reduced prokaryotic diversity and network complexity and stability, with weak disruption of the eukaryotic structure. Small omnivorous fish were major drivers of changes eukaryotic periphyton, facilitating diversity and network complexity, and increasing prokaryotic and eukaryotic biomarker diversity. Omnivorous fish reduced the grazing pressure on periphyton mainly through selective grazing on zooplankton, contributing to periphytic structural stability and functional diversity, especially the proliferation of prokaryotic biomarkers. Nutrient enrichment counteracted the positive effects of warming on periphyton, while concerted action with omnivorous fish led to high TN and TP concentrations and accelerated the negative development of periphytic alpha diversity and network structure. The co-occurrence of the three environmental pressures ultimately resulted in a disruption of periphytic biodiversity and community structure and weakened connectivity with the environment. Our study provided new insights into the understanding of the response of prokaryotic and eukaryotic community structure and ecological functions of freshwater periphyton to global environmental change.

A cytochrome bd repressed by a MarR family regulator confers resistance to metals, nitric oxide, sulfide, and cyanide in Chromobacterium violaceum.

The terminal oxidases of bacterial respiratory chains rely on heme-copper (heme-copper oxidases) or heme (cytochrome bd) to catalyze the reduction of molecular oxygen to water. Chromobacterium violaceum is a facultative anaerobic bacterium that uses oxygen and other electron acceptors for respiration under conditions of varying oxygen availability. The C. violaceum genome encodes multiple respiratory terminal oxidases, but their role and regulation remain unexplored. Here, we demonstrate that CioAB, the single cytochrome bd from C. violaceum, protects this bacterium against multiple stressors that are inhibitors of heme-copper oxidases, including nitric oxide, sulfide, and cyanide. CioAB also confers C. violaceum resistance to iron, zinc, and hydrogen peroxide. This cytochrome bd is encoded by the cioRAB operon, which is under direct repression by the MarR-type regulator CioR. In addition, the cioRAB operon responds to quorum sensing and to cyanide, suggesting a protective mechanism of increasing CioAB in the setting of high endogenous cyanide production.

Comprehensive review of mapping climate change impacts on tea cultivation: bibliometric and content analysis of trends, influences, adaptation strategies, and future directions

Climate change has a profound impact on tea cultivation, posing significant challenges to yield, quality, and sustainability due to stressors such as drought, temperature fluctuations, and elevated CO₂ levels. This study aims to address these challenges by identifying and synthesizing key themes, influential contributions, and effective adaptation strategies for mitigating the impacts of climate change on tea production. A systematic bibliometric and content analysis was conducted on 328 peer-reviewed documents (2004–2023), following the PRISMA methodology. Performance analysis using Bibliometrix examined trends in publication output, leading contributors, and geographical distribution, while science mapping with VOSviewer revealed collaboration networks and thematic clusters. A detailed review of highly cited studies highlighted the primary climate variables affecting tea cultivation and identified innovative adaptation strategies, as well as critical knowledge gaps. The results show significant progress in understanding the physiological, biochemical, and molecular responses of tea plants to climate-induced stressors, including antioxidant mechanisms, secondary metabolite regulation, and genomic adaptations. Despite these advancements, challenges remain, particularly regarding the combined effects of multiple stressors, long-term adaptation strategies, and the socioeconomic implications of climate change. The findings underscore the need for interdisciplinary approaches that integrate molecular, ecological, and socioeconomic research to address these issues. This study provides a solid foundation for guiding future research, fostering innovative adaptation strategies, and informing policy interventions to ensure sustainable tea production in a changing climate.

Ecological interactions amplify cumulative effects in marine ecosystems.

Biodiversity encompasses not only species diversity but also the complex interactions that drive ecological dynamics and ecosystem functioning. Still, these critical interactions remain overwhelmingly overlooked in environmental management. In this study, we introduce an ecosystem-based approach that assesses the cumulative effects of climate change and human activities on species in the St. Lawrence marine ecosystem, eastern Canada, by explicitly accounting for the effects arising from species interactions within a multiple stressors framework. Our findings reveal previously unrecognized threats to exploited and endangered fishes and marine mammals, exposing noteworthy gaps in existing management and recovery strategies. By integrating the less obvious yet no less substantial effects arising from species interactions into cumulative effects assessments, our approach provides a robust tool to guide more comprehensive and effective management and conservation efforts for marine species.

Environmental thresholds of semiaquatic bugs (Heteroptera, Gerromorpha) as an indicator of environmental change in Amazon streams.

Freshwater ecosystems under the influence of human activities are subject to multiple environmental stressors that lead to biodiversity loss and habitat modification. In recent years, various organisms have been used as bioindicators to detect environmental changes by their ability to perceive changes in community attributes. A good example is the semiaquatic bugs (Hemiptera, infra order Gerromorpha) that act as predators and are sensitive to subtle changes in environmental conditions. Our research aimed to investigate the responses of Gerromorpha communities, genera, and species along an environmental gradient in 45 Amazon streams. The environmental gradient was assessed utilizing the Habitat Integrity Index (HII) across the sampled streams, yielding a collection of 2.212 specimens representing three families, seven genera, and 36 species. The habitat integrity, represented by the HII, showed a positive relationship between species richness and the richness of genera of Gerromorpha, underscoring that both species and genera respond to environmental change in the analyzed habitats. Brachymetra lata (Gerridae), Rhagovelia jubata, and R. elegans (Veliidae) were the most sensitive taxa with a positive relationship to HII. Streams characterized by higher anthropogenic disturbance and reduced riparian vegetation were associated with a biodiversity pattern marked by increased abundance and frequency of generalist species and reduced genus frequency within the Veliidae family. We hope that the results of this study will contribute to future biomonitoring programs in response to habitat and species loss, aiming to assist decision-making to protect and restore riparian vegetation areas.

Stress assessment instruments for hospitalized preterm newborns: scoping review

BackgroundThe highly technological environment existing in intensive care units, essential for the survival of the newborn, contributes with a potentially devastating and traumatic effect, especially in preterm newborns and in their future lives, due to the early and frequent exposure to multiple stressors. The preterm newborn must be observed in a systematic and structured way, before, during and after any intervention, aiming at the correct assessment and interpretation of his behaviour and signs of stress, and at the timely planning of interventions that minimize and prevent stress. The objective of this review is to identify and map the instruments for assessing stress in preterm newborns admitted to neonatal units in scientific evidence.MethodsA scoping review was carried out using the methodology presented by The Joanna Briggs Institute (JBI) and the PRISMA ScR model (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extended for Scoping Reviews) for structuring the collected information. The research was carried out in three distinct phases supported by the Medline, CINALH databases through the EBSCO, Scielo and PubMed platform. Two reviewers screened all citations, abstract data and full-text articles, independently.ResultsTen articles were selected, all primary studies. Seven different scales were identified in the studies.DiscussionThis review highlights the limited availability of instruments exclusively designed to assess neonatal stress in neonatology. While most tools, like the Newborn Comfort Behavior Scale and ALPS-Neo, focus on pain and stress together, the NISS and NSS provide valuable insights despite limitations in capturing individualized stress responses. Differentiating stress from pain is crucial for implementing targeted, neuroprotective interventions. Adapting neonatology environments and care practices to minimize stressors is essential for promoting newborns' well-being and long-term development.ConclusionThe findings underscore the critical need for stress-specific assessment tools in NICUs to differentiate between pain and stress. Existing instruments offer valuable insights but have notable limitations. Expanding validated tools and prioritizing individualized, neuroprotective care are essential for improving outcomes. Adapting neonatology practices to reduce stressors and implement family-centered care will support the holistic needs of newborns, fostering their development, physiological stability, and overall well-being.System review registrationOpen Science Framework (https://osf.io/nsu95/).

Genome-Wide Analyses Reveal the Roles of CCT Genes as Regulators of Abiotic Stress Responses in Citrullus lanatus

Members of the CCT gene family have been shown to play roles in photoperiodic flowering and environmental adaptation under a range of conditions. In this study, 29 CCT genes from watermelon were categorized into three distinct subfamilies. The ClCCT genes were systematically analyzed, focusing on their physicochemical properties, gene duplication, motifs, structural divergence, promoter regions, and collinearity with genes from other species. The responsiveness of these genes to abiotic stressors, hormone treatments, and photoperiod prolongation was also examined. Segmental duplication (gene amplification) significantly influenced the evolution of these genes, with most ClCCT genes containing light-, hormone-, and/or abiotic stimulus-responsive elements. In response to abiotic and hormonal stresses, 5 genes responded to cold, 1 gene to drought, and 4 genes to salt. 6 genes were responsive to ABA, and 13 genes to MeJA. Strikingly, ClCCT17, ClCCT4, and ClCCT28 responded to multiple stressors. A majority of these ClCCT genes and their homologs in other species were responsive to prolonged daylight exposure. The varying expression patterns of these genes suggested a key role for watermelon CCT genes in the regulation of both abiotic stress responses and flowering. Functional diversity was also evident among CCT family genes within a given species as well as among species attributable to changes in the structural features and expression patterns of the genes and the encoded proteins.

Psychiatric diagnoses of professional musicians: Results of an outpatient service specializing in musicians’ health

Professional musicians are often confronted with multiple profession-related stressors, which may be associated with an increased risk of mental strain, but empirical evidence focusing on clinical samples of musicians is limited. The aim of this study was to examine clinically confirmed mental disorders and personality accentuations in musicians attending a musician-specific outpatient service, to better understand how occupational and person-related stressors may impact their mental health. We performed a cross-sectional secondary data analysis of diagnoses and sociodemographic data of 678 professional musicians (including music students) that were routinely collected in the outpatient clinic. Of the 678 patients, 110 (16.2%) received a tentative psychiatric diagnosis, and 46 presented themselves to the psychiatric outpatient clinic for extensive diagnostics (using ICD-10 and SKID-II). In these 46 musicians, depression (39%) and music performance anxiety (26%) were the most frequent diagnoses, followed by adjustment disorders (13%) and somatoform disorders (11%). Twenty-eight percent of the sample fulfilled the criteria of either a personality disorder or accentuation. The frequency rates emphasize the importance of targeting the mental health of professional musicians with preventive and therapeutic measures. Further research with larger sample sizes is needed to validate and extend our findings and develop individual preventive measures.

Asynchronous effects of heat stress on growth rates of massive corals and damselfish in the Red Sea.

Climate change is imposing multiple stressors on marine life, leading to a restructuring of ecological communities as species exhibit differential sensitivities to these stressors. With the ocean warming and wind patterns shifting, processes that drive thermal variations in coastal regions, such as marine heatwaves and upwelling events, can change in frequency, timing, duration, and severity. These changes in environmental parameters can physiologically impact organisms residing in these habitats. Here, we investigate the synchrony of coral and reef fish responses to environmental disturbance in the Red Sea, including an unprecedented combination of heat stress and upwelling that led to mass coral bleaching in 2015. We developed cross-dated growth chronologies from otoliths of 156 individuals of two planktivorous damselfish species, Pomacentrus sulfureus and Amblyglyphidodon flavilatus, and from skeletal cores of 48 Porites spp. coral colonies. During and immediately after the 2015 upwelling and bleaching event, damselfishes exhibited a positive growth anomaly but corals displayed reduced growth. Yet, after 2015-2016, these patterns were reversed with damselfishes showing a decline in growth and corals rebounding to pre-disturbance growth rates. Our results reveal an asynchronous response between corals and reef fish, with corals succumbing to the direct effects of heat stress, and then quickly recovering when the heat stress subsided-at least, for those corals that survived the bleaching event. Conversely, damselfish growth temporarily benefited from the events of 2015, potentially due to the increased metabolic demand from increased temperature and increased food supply from the upwelling event, before declining over four years, possibly related to indirect effects associated with habitat degradation following coral mortality. Overall, our study highlights the increasingly complex, often asynchronous, ecological ramifications of climate extremes on the diverse species assemblages of coral reefs.

Mental health of children and adolescents from migrant families in Lausanne, Switzerland

ABSTRACT Migration can put an important psychological stress on families. The aim of this study was to assess the mental health of migrant children and their parents followed at the Children’s Hospital of Lausanne (HEL) in Switzerland to emphasize potential areas for intervention. We conducted an exploratory study at the Policlinic of HEL from March 2021 to December 2022. Questionnaires included the Strengths & Difficulties Questionnaire (SDQ) addressed to children aged 4–17 years old, the World Health Organisation-Five Well-Being Index (WHO-5) filled in by their parents and socio-demographic questions related to migration. Forty-two children of 33 families (26 mothers, 7 fathers) were included. A raised total difficulties score was observed in 19% of children, emotional problems in 26%, conduct problems in 24% and peer problems in 21% of them. Longer stay in Switzerland correlated with higher total difficulties (p = 0.001), emotional problems (p = 0.0099) and conduct problems (p = 0.0080). Children with insecure legal status and those in single-parent families had higher total difficulties scores (p = 0.041 and p = 0.018, respectively). Thirty percent of parents had a WHO-5 score ≤ 50, indicating poor well-being (n = 30), which was associated with increased emotional problems(p = 0.049) and lower prosocial scores (p = 0.006) in children. While many migrant children exhibit resilience, this study emphasizes their susceptibility to multiple chronic stressors in the post-migration phase.

Double trouble? Quantifying the risk from co-exposure to multiple pathogens in Tenebrio molitor at different CO2 concentrations.

The insect mass-rearing industry to produce feed and food is expanding rapidly. Insects in production frequently encounter multiple pathogens and environmental stressors simultaneously, which can lead to significant economic losses. Our understanding of the interactions between different stressors remains limited, and existing methods primarily focus on determining overall patterns of additivity, synergism, or antagonism. However, the interactions between different stressors may exhibit more intricate response patterns, such as time or dose dependency. With the expanding industry of insect production, it becomes vital to conduct comprehensive risk assessment of diseases, using approaches that can detect both lethal and sublethal effects. Here, we assessed the risk of co-exposure to a fungal (Metarhizium brunneum) and a bacterial (Bacillus thuringiensis) pathogen in the yellow mealworm (Tenebrio molitor) at ambient and elevated carbon dioxide (CO2) concentrations. We assessed total larval biomass per treatment group, survival, and individual weight gain 14 and 20 days after pathogen exposure. To analyse the data, we used a mixture toxicity (MIXTox) model, which identifies dose ratio or dose level dependency in addition to overall antagonism or synergism. The interactions between the two pathogens were mostly antagonistic or additive at both CO2 concentrations and time points, indicating that the observed effects during co-exposure did not exceed the expected combined effects of the individual exposure. We did not find evidence that the interactions between the pathogens substantially change at elevated CO2. The antagonistic interactions measured in the bioassays are likely to be indirect via the insect host, as we did not detect direct inhibition between the two pathogens in in vitro experiments. Here we show that using the MIXTox model is a powerful tool to assess the effects of co-exposure to pathogens and quantify risk of disease in mass-reared insects.

Reconciling Variability in Multiple Stressor Effects Using Environmental Performance Curves.

Understanding the effects of multiple stressors has become a major focus in ecology and evolution. While many studies have investigated the combined effects of stressors, revealing massive variability, a mechanistic understanding that reconciles the diversity of multiple stressor outcomes is lacking. Here, we show how performance curves can fill this gap by revealing mechanisms that shape multiple stressor outcomes. Our experiments with 12 bacterial taxa, demonstrate that additional stressors alter the shape of temperature, pH and salinity performance curves. This leads to changes in stressor interaction outcomes-for example, shifts between additive, antagonistic or synergistic interactions-along gradients, revealing that small changes in a stressor along nonlinear performance curves can dramatically impact the stressor interaction. These findings help to explain the lack of generality found across multiple stressor studies and highlight how a performance curve approach can provide a more holistic view of multiple stressor interactions.

Interactive effects of temperature, cadmium, and hypoxia on rainbow trout (Oncorhynchus mykiss) liver mitochondrial bioenergetics

Fish in their natural environments possess elaborate mechanisms that regulate physiological function to mitigate the adverse effects of multiple environmental stressors such as temperature, metals, and hypoxia. We investigated how warm acclimation affects mitochondrial responses to Cd, hypoxia, and acute temperature shifts (heat shock and cold snap) in rainbow trout. We observed that state 3 respiration driven by complex I (CI) was resistant to the stressors while warm acclimation and Cd reduced complex I +II (CI + II) driven state 3 respiration. In contrast, state 4 (leak) respirations for both CI and CI + II were consistently stimulated by warm acclimation resulting in reduced mitochondrial coupling efficiency (respiratory control ratio [RCR]). Warm acclimation and Cd exacerbated their individual effect on leak respiration to further reduce the RCR. Moreover, the effect of warm acclimation on mitochondrial bioenergetics aligned with its inhibitory effect on activities of citrate synthase and both CI and CII. Unlike the Cd and warm acclimation combined exposure, hypoxia alone and in combination with warm acclimation and/or Cd abolished the stimulation of CI and CI + II powered leak respirations resulting in partial recovery of RCR. The response to acute temperature shifts indicated that while state 3 respiration returned to pre-acclimation level, the leak respiration did not. Overall, our findings suggest a complex in vivo interaction of multiple stressors on mitochondrial function that are not adequately predicted by their individual effects.

LGR4 is essential for maintaining β-cell homeostasis through suppression of RANK.

Loss of functional β-cell mass is a major cause of diabetes. Thus, identifying regulators of β-cell health is crucial for treating this disease. The Leucine-rich repeat-containing G-protein-coupled receptor (GPCR) 4 (LGR4) is expressed in β-cells and is the fourth most abundant GPCR in human islets. Although LGR4 has regenerative, anti-inflammatory, and anti-apoptotic effects in other tissues, its functional significance in β-cells remains unknown. We have previously identified Receptor Activator of Nuclear Factor Kappa B (NFκB) (RANK) as a negative regulator of β-cell health. In this study, we assessed the regulation of Lgr4 in islets, and the role of LGR4 and LGR4/RANK stoichiometry in β-cell health under basal and stress-induced conditions, invitro and invivo. We evaluated Lgr4 expression in mouse and human islets in response to acute (proinflammatory cytokines), or chronic (high fat fed mice, db/db mice, and aging) stress. To determine the role of LGR4 we employed invitro Lgr4 loss and gain of function in primary rodent and human β-cells and examined its mechanism of action in the rodent INS1 cell line. Using Lgr4fl/fl and Lgr4fl/fl/Rankfl/fl×Ins1-Cre mice we generated β-cell-specific conditional knockout (cko) mice to test the role of LGR4 and its interaction with RANK invivo under basal and stress-induced conditions. Lgr4 expression in rodent and human islets was reduced by multiple stressors. Invitro, Lgr4 knockdown decreased proliferation and survival in rodent β-cells, while overexpression protected against cytokine-induced cell death in rodent and human β-cells. Mechanistically, LGR4 protects β-cells by suppressing RANK- Tumor necrosis factor receptor associated factor 6 (TRAF6) interaction and subsequent activation of NFκB. Lgr4cko mice exhibit normal glucose homeostasis but increased β-cell death in both sexes and decreased β-cell proliferation and maturation only in females. Male Lgr4cko mice under stress displayed reduced β-cell proliferation and a further increase in β-cell death. The impaired β-cell phenotype in Lgr4cko mice was rescued in Lgr4/Rank double ko (dko) mice. Upon aging, both male and female Lgr4cko mice displayed impaired β-cell homeostasis, however, only female mice became glucose intolerant with decreased plasma insulin. These data demonstrate a novel role for LGR4 as a positive regulator of β-cell health under basal and stress-induced conditions, through suppressing the negative effects of RANK.

Multiple stressor effects act primarily on microbial leaf decomposers in stream mesocosms.

At the global level, stream ecosystems are influenced by multiple anthropogenic stressors such as eutrophication, habitat deterioration, and water scarcity. Multiple stressor effects on stream biodiversity are well documented, but multiple stressor effects on stream ecosystem processes have received only limited attention. We conducted one mesocosm (stream channel) and one microcosm (feeding trial) experiment to study how combinations of reduced flow, increased nutrient concentrations, and increased fine sediment coverage would influence fungal and macroinvertebrate decomposer assemblages and their active contribution to leaf decomposition. In the stream channels, increased fine sediment coverage significantly reduced fungal biomass, occurrence frequencies of most aquatic hyphomycete species, and microbial leaf decomposition rates compared to untreated controls. Macroinvertebrate-induced leaf decomposition rates were mainly correlated to total fungal biomass and community composition. Neither increased nutrient concentrations, nor reduced flow conditions significantly influenced leaf decomposer communities or decomposition rates. The feeding trials revealed significantly reduced leaf consumption in the freshwater amphipod Gammarus pulex when feeding on leaf material from treatments with increased fine sediment coverage in the mesocosm experiment. When offered a food choice between sterile, unconditioned leaf material and leaf material from treatments with increased fine sediment coverage, G. pulex foraged mainly on sterile material. This study showed that increased fine sediment coverage can alter the flux of energy and material in the detrital food chain through bottom-up regulation of leaf conditioning by fungal decomposers. Our results suggest that increasing attention should be given to mitigating fine sediment transport and deposition in stream systems to preserve ecosystem functioning within the detrital food chain.

Hormetic response to pesticides in diapausing bees.

Pollinators face declines and diversity loss associated with multiple stressors, particularly pesticides. Most pollination services are provided by annual bees that undergo winter diapause, and many common pesticides are highly soluble in water and move through soil and plants where bees hibernate and feed, yet the effects of pesticides on pollinators' diapause survival and performance are poorly understood. Pesticides may have complex effects in bees, and some were shown to induce hormetic effects on various traits characterized by high-dose inhibition coupled with low-dose stimulation. Here, we examined the occurrence of hormesis in the responses of bees to imidacloprid. We found that while longevity and reproduction were reduced following exposure to imidacloprid, the survival length of new queens (gynes) was greater. Diapause is a critical period in the life cycle of most bees with profound effects on their health. Exposure to sublethal doses of pesticides may increase bees' resistance to stress/cold during diapause but may also trade off with reduced reproductive performance later in life. Identifying these trade-offs is crucial to understanding how stressors affect pollinator health and should be accounted for when assessing pesticide risk, designing studies and facilitating conservation and management tools for supporting annual bees during diapause.

Elevated CO2 alleviates negative impacts of high temperature and salinity on phytohormones, photosynthesis, and redox reactions in leaves of Caragana korshinskii kom.

In this research, we sought to investigate how high temperature, salinity, and CO2 affect endogenous phytohormones, photosynthesis, and redox homeostasis in Caragana korshinskii Kom (C. korshinskii) leaves, as well as to comprehensively evaluate the plant's physiological response to multiple environmental stressors. The elevated temperature (e[T]), elevated Na+ (e[Na]), and elevated temperature and Na+ (e[T-Na]) treatments increased abscisic acid (ABA) and reduced zeatin-riboside (ZR), indole-3-acetic acid (IAA), and gibberellic acid (GA3). These changes induced stomatal closure, and the subsequent reduction in photosynthetic rate triggered the generation of superoxide anion (O2·-) and hydrogen peroxide (H2O2). In response, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activity increased, and free proline and total soluble sugars were accumulated. However, membrane lipid peroxidation was still aggravated. Under elevated CO2 (e[CO2]), the dramatic hormonal fluctuations and photosynthetic inhibition resulting from e[T], e[Na], and e[T-Na] were alleviated. Moreover, e[CO2] reduced ROS generation caused by e[T], e[Na], and e[T-Na], and stabilized antioxidant enzyme activities and non-enzymatic compound concentrations. Compared with e[T], e[Na], and e[T-Na], the increased malondialdehyde (MDA) content was effectively alleviated under elevated CO2 and temperature (e[CO2-T]), elevated CO2 and Na+ (e[CO2-Na]), and elevated CO2, temperature, and Na+ (e[CO2-T-Na]). Overall, our research suggest that e[CO2] may alleviate the negative impacts of e[T] and e[Na] on plant physiology.

Fish models to explore epigenetic determinants of hypoxia-tolerance.

The occurrence of environmental hypoxia in freshwater and marine aquatic systems has increased over the last century and is predicted to further increase with climate change. As members of the largest extant vertebrate group, freshwater fishes, and to a much lesser extent marine fishes, are vulnerable to increased occurrence of hypoxia. This is important as fishes render important ecosystem services and have important cultural and economic roles. Evolutionarily successful, fishes have adapted to diverse aquatic freshwater and marine habitats with different oxygen conditions. While some fishes exhibit genetic adaptions to tolerate hypoxia and even anoxia, others are limited to oxygen-rich habitats. Recent advances in molecular epigenetics have shown that some epigenetic machinery, especially histone- and DNA demethylases, is directly dependent on oxygen and modulates important transcription-regulating epigenetic marks in the process. At the post-transcriptional level, hypoxia has been shown to affect non-coding microRNA abundance. Together, this evidence adds a new molecular epigenetic basis to study hypoxia tolerance in fishes. Here, we review the documented and predicted changes in environmental hypoxia in aquatic systems and discuss the diversity and comparative physiology of hypoxia tolerance in fishes, including molecular and physiological adaptations. We then discuss how recent mechanistic advances in environmental epigenetics can inform future work probing the role of oxygen-dependent epigenetic marks in shaping organismal hypoxia-tolerance in fishes with a focus on within- and between-species variation, acclimation, inter- and multigenerational plasticity, and multiple climate-change stressors. We conclude by describing the translational potential of this approach for conservation physiology, ecotoxicology, and aquaculture.