Exposure Experiments Research Articles

Interplay of Structural Properties and Redox Behavior in CeO2 Nanoparticles: Impact on Reactivity and Bioavailability.

The environmental redox transformation of CeO2 is crucial for evaluating its ecological risk and understanding the geochemical cycling of cerium (Ce). In this study, we examined the effects of crystallinity on CeO2 dissolution and monitored the structural evolution during redox transformations. The reductive dissolution and reoxidation behavior of CeO2 (100 mg/L) was examined in the presence of 200 μM citrate. Our findings indicate that ligand-induced dissolution is more pronounced in CeO2 with lower crystallinity under both dark and light conditions. This dependence is related to the intensive ligand complexation at oxygen vacancy sites, resulting in a higher complexation of Ce(III) and more efficient photoelectron generation for Ce(IV) reduction. During cyclic dissolution-reprecipitation, CeO2 notably transformed into an amorphous phase, progressively decreasing the crystallinity of the nanoparticles. Consequently, the dissolution fraction of well-crystallized CeO2 increased significantly from 1.2% in the first cycle to 11.4% in the third cycle, suggesting a transition to structures with higher interfacial reactivity. Similar transformation and dissolution behavior was observed in redox oscillations in a soil environment. Additionally, hydroponic exposure experiments with Arabidopsis thaliana, treated with 100 mg/L CeO2 for 7 days, demonstrated increased Ce uptake by roots post-transformation, with a higher proportion of CePO4 detected within the plants. This comprehensive study not only provides vital mechanistic insights into the transformation processes of CeO2 but also aids in assessing the ecological risks associated with engineered CeO2 nanomaterials.

ZFIN Updates to Support Zebrafish Environmental Exposure Data.

The Zebrafish Information Network (ZFIN, zfin.org) is the database resource for genetic, genomic, and phenotypic data from research using zebrafish, Danio rerio. ZFIN curates information about genetic perturbations, gene expression, phenotype, gene function, and human disease models from zebrafish research publications and makes these data available to researchers worldwide. Over the past 20 years, zebrafish have increasingly been used to investigate the effects of environmental exposures, becoming an ideal model to study toxicity, phenotypic outcomes, and gene-chemical interactions. Despite this, database resources supporting zebrafish toxicology and environmental exposure research are limited. To fill this gap, ZFIN has expanded functionality to incorporate and convey toxicology data better. ZFIN annotations for gene expression, phenotype, and human disease models include information about genotypes and experimental conditions used. One type of experimental condition the database captures is the application of chemicals to zebrafish. ZFIN annotates chemicals using the Chemical Entities of Biological Interest Ontology (ChEBI) along with the Zebrafish Experimental Conditions Ontology (ZECO) to denote route of exposure and other experimental conditions. These features allow researchers to search phenotypes and human disease models linked to chemicals more efficiently. Here we discuss how experimental conditions are displayed on ZFIN web pages, the data displayed on chemical term pages, and how to search and download data associated with chemical exposure experiments.

Constraints on neutrino nonstandard interactions from COHERENT, PandaX-4T and XENONnT

We investigate constraints on neutrino nonstandard interactions (NSIs) in the effective field theory framework, using data from the first measurement of solar B8 neutrinos via coherent elastic neutrino-nucleus scattering (CEνNS) in the PandaX-4T and XENONnT experiments and data from the COHERENT experiment. The impacts of neutrino NSIs on the CEνNS cross section and the matter effect in the propagation of solar neutrinos are included, while we obtain that the expected number of CEνNS events is more sensitive to neutrino NSIs appearing in the cross section. Due to relatively large statistical uncertainties, the sensitivities of the PandaX-4T and XENONnT experiments to the neutrino NSIs are currently limited, compared to the COHERENT experiment. Besides, we find that since the central value of the measured CEνNS counts significantly differs from the Standard Model prediction, the sensitivity of PandaX-4T experiment is even more restricted compared to XENONnT. However, the measurements of PandaX-4T and XENONnT are uniquely sensitive to the neutrino NSIs for the τ flavor due to oscillation feature of the solar B8 neutrinos. We also assess how the experimental central value, exposure, and systematic uncertainties will affect the constraints on neutrino NSIs from various CEνNS measurements in the future. Published by the American Physical Society 2025

A parameterized model of center-symmetric space deployable arrays inspired by Miura and five-crease origami

Thick-panel origami has gained significant attention for its potential applications in the design of space deployable arrays. However, existing origami structures often fail to meet the stringent constraints imposed by various spacecraft in terms of connectivity and space efficiency, limiting the achievement of optimal folding ratios and compact transportation. To address these challenges, we propose a parameterized geometric model and design method for center-symmetric thick-panel space deployable arrays for varying scales and functions, integrating five-crease vertices with Miura origami. A planar four-bar linkage mechanism is applied to coordinate the motion between the five-crease vertices and Miura origami, ensuring one-degree-of-freedom (one-DOF) motion. The proposed model is validated through a case study on a space exposure experiment platform, with a scaled-down prototype fabricated for testing. The resulting space deployable arrays can be compactly placed within a rectangular prism, offering central symmetry, one-DOF motion, high volume efficiency and folding ratio, and enhanced design flexibility and adaptability.

Polystyrene microplastics exacerbate acetochlor-induced reproductive toxicity and transgenerational effects in zebrafish.

Microplastic (MPs) can adsorb co-existing pollutants, and alter their behavior and toxicity. Meanwhile, amide herbicides like acetochlor (ACT) are widely used in agriculture, with potential endocrine-disrupting effects that raise ecological concerns. The aim of this research was to examine the effects of MPs on the reproductive endocrine disruption caused by ACT and the effects of maternal transmission. Zebrafish were employed in this study to assess the reproductive toxicity of ACT alone and in combination with polystyrene microplastics (PS-MPs) of different sizes (200 nm and 2 μm) and concentrations (0.1 and 1 mg/L) over a 63-day exposure experiment. The results indicated that ACT was concentrated in zebrafish tissues in the order: intestine > liver > gill > brain > gonad > muscle. PS-MPs increased ACT bioaccumulation, worsened gonadal damage, led to abnormalities in hormone levels, and caused disruptions in HPG axis gene expression, further exacerbating the reproductive toxicity. Maternal transfer of ACT affected offspring growth, thyroid function, and HPT axis gene expression, with nanoplastics (NPS) amplifying these adverse effects. This study offers crucial insights into the ecological hazards posed by ACT and PS-MPs, emphasizing the increased toxicity due to PS-MPs.

Unveiling potential biomarkers and associated health risks of chronic experimental exposure to environmentally relevant concentration of metalaxyl: An untargeted metabolomics approach

Unveiling potential biomarkers and associated health risks of chronic experimental exposure to environmentally relevant concentration of metalaxyl: An untargeted metabolomics approach

Preservation of Vascular Endothelial Function in Late-Onset Postmenopausal Women.

Postmenopausal women (PMW) who complete menopause at a late age (55+ years) have lower cardiovascular disease risk than PMW who complete menopause at a normal age (45-54 years). However, the influence of late-onset menopause on vascular endothelial dysfunction is unknown. Moreover, the mechanisms by which a later age at menopause may modulate endothelial function remain to be determined. We measured endothelial function (brachial artery flow-mediated dilation [FMDBA]) in age-matched late- and normal-onset PMW and a young premenopausal reference group. We determined mitochondrial reactive oxygen species (mitoROS)-related suppression of endothelial function (change in FMDBA with an acute dose of the mitochondria-targeted antioxidant MitoQ; ΔFMDBA, MTQ) in PMW. The effects of serum from late- and normal-onset PMW and premenopausal women on mitoROS bioactivity in human aortic endothelial cells in culture were assessed. Metabolomics analyses in combination with serum metabolite level normalization and human aortic endothelial cell serum exposure experiments were performed to identify the circulating factors contributing to the serum effects on endothelial cell mitoROS bioactivity. FMDBA in PMW was lower than in premenopausal women. However, FMDBA was >50% higher in late- versus normal-onset PMW and positively related to age at menopause. ΔFMDBA, MTQ was >50% lower in late- versus normal-onset PMW. Serum from normal-onset PMW but not late-onset PMW induced higher mitoROS bioactivity in human aortic endothelial cells compared with serum from premenopausal women. mitoROS bioactivity was negatively related to FMDBA and age at menopause. Seventeen metabolites significantly differed between late- and normal-onset PMW; 15 were lipid specific; 8 were triglyceride derived. TG(16:0) was most strongly correlated with mitoROS bioactivity. Normalization of TG(16:0) concentrations in serum from premenopausal women and late-onset PMW to match serum levels in normal-onset PMW abrogated differences in mitoROS bioactivity in serum-treated human aortic endothelial cells. Late-onset menopause is associated with preservation of endothelial function, which is mediated by lower mitoROS-associated oxidative stress. A more favorable profile of circulating lipid metabolites, specifically triglyceride-derived metabolites, contributes to lower endothelial cell mitoROS in late-onset PMW. These findings provide new insight into the possible mechanisms of reduced cardiovascular disease risk in late-onset menopause.

Studying interaction effects on toxicokinetics in zebrafish combining experimental and modelling approaches.

Humans and wildlife are exposed to a complex mixture of anthropogenic chemicals of which only a few have been subjected to regulations. Chemical risk assessment is currently based on evaluating single chemicals, which is costly, time-consuming, and neglect toxicokinetic and toxicodynamic mixture effects. This study focused on interaction effects on the absorption, distribution, metabolism and excretion (ADME) processes of selected chemicals representing potential modulators of these processes. Adult female zebrafish (Danio rerio) were exposed to selected mixture of 11 chemicals and bioconcentration factors (BCFs) on tissue level were determined for 9 of them: bisphenol A (BPA), bisphenol AF (BPAF), bisphenol Z (BPZ), triclosan, tribromophenol, pentachlorophenol, heptafluorobutyric acid (PFBA), perfluorobutanesulfonic acid (PFBS), and perfluorooctanesulfonic acid (PFOS). Comparison of BCFs of bisphenols obtained from single chemical exposure experiments versus the current study revealed no statistically significant differences (p>0.05), implying no mixture effects on kinetics of bisphenols at investigated concentrations. The same conclusion was reached using two physiologically based kinetic (PBK) models, developed for individual bisphenols and per- and polyfluoroalkyl substances (PFAS), showing good model fit for BPA, BPZ, BPAF, and PFOS. To simulate exposure scenarios where kinetic interaction effects may occur through competitive protein binding in blood, a new PBK model was developed. Simulations where zebrafish were dosed with BPA and BPZ, individually, and combined with varying levels of PFOS, showed that competitive binding to serum proteins alter tissue levels of bisphenols when levels of PFOS exceeded 1μg/L. This indicates that chemicals acting in concert could perturb ADME but only at higher levels or in complex mixtures.

A comprehensive assessment of membrane bioreactor contaminant removal efficacy through analytical chemistry, fish exposures, and microbiome characterization.

Treated municipal wastewater effluent is an important pathway for Contaminants of Emerging Concern (CEC) to enter aquatic ecosystems. As the aging wastewater infrastructure in many industrialized countries requires upgrades or replacement, assessing new treatment technologies in the context of CEC effects may provide additional support for science-based resource management. Here, we used three lines of evidence, analytical chemistry, fish exposure experiments, and fish and water microbiome analysis, to assess the effectiveness of membrane bioreactor treatment (MBR) to replace traditional activated sludge treatment. To do this, we sampled a municipal wastewater treatment plant with a split wastewater stream, a portion of which was treated with an MBR and another via an oxidation ditch (OXI). The OXI and MBR treatments substantially reduced most measured CECs compared to the primary effluent (PRI). Only pesticides and some pharmaceuticals were recalcitrant to both secondary treatment methods. While ammonia toxicity of PRI prevented its inclusion in fish exposure experiments, exposure of fish with waters from the OXI or MBR treated wastewater produced only subtle biological differences with no adverse apical outcomes. These findings were consistent with low chemically derived exposure: activity ratios (EARs) for OXI and MBR. Microbiome analysis of fish and wastewater highlighted the significant reduction of microbial abundance and diversity in the MBR treatment compared to all other treatments. The comparable removal efficacy of CECs in MBR makes it an attractive alternative to traditional OXI, especially when MBR may eliminate the need for tertiary treatment for wastewater disinfection.

Plastic nanoparticle toxicity is accentuated in the immune-competent inflamed intestinal tri-culture cell model

Introduction: Important cell-based models of intestinal inflammation have been advanced in hopes of predicting the impact of nanoparticles on disease. We sought to determine whether a high level and extended exposure of nanoplastic might result in the added intestinal inflammation caused by nanoplastic reported in a mouse model of irritable bowel disease. Methods: The cell models consist of a Transwell©-type insert with a filter membrane upon which lies a biculture monolayer of Caco-2 and HT29-MTX-E12 made up the barrier cells (apical compartment). This monolayer was exposed to digested 40 nm diameter polymethacrylate (PMA) with surface-functionalized COOH (PMA-) or NH2 (PMA+) at a ‘low level’ (143 µg/cm2 monolayer surface area) or ‘high level’ (571 µg/cm2) for 24 or 48 h. Beyond the apical compartment in the well of the tissue culture plate, was a monolayer of macrophages, previously differentiated from THP-1 cells (basolateral compartment). Thus, the immune competent tri-cultures were examined as two models: healthy and inflamed. The inflamed model, the barrier cell monolayer having been previously activated with IFN-γ and the macrophages having been previously activated with IFN-γ and LPS expressed a greater secretion of pro-inflammation cytokines. Results: Sedimentation, Diffusion and Dosimetry model (ISDD) simulated that 8%–12% of the PMA was deposited onto the barrier cell monolayer in 24–48-h. The structure of the barrier cells in the inflamed model was disorganized for both PMA, high level, 48-h experiments. While neither the amount of PMA nor the exposure duration influenced the lactate dehydrogenase (LDH) secretion in the healthy model, only the high levels of both PMA- and PMA+ in 48-h exposure experiments resulted in a significantly increased LDH secreted by the barrier cells in the inflamed model, compared to inflamed control. This study is the first to show an additive inflammation of nanoplastic in an inflamed intestinal model of the intestine.

Toxicity mechanism of metal-organic framework HKUST-1 and its carbonized product to Tetradesmus obliquus: Physiological and transcriptomic analysis.

Metal-organic frameworks (MOFs) are emerging materials with unique structures and properties, which have been widely used in many fields due to their various advantages. However, compared with its popular application research, the ecological safety of MOFs has rarely been reported. In this paper, a biological model, the common freshwater green algae Tetradesmus obliquus (T. obliquus) was used to study the effects of the copper-based MOF HKUST-1 and its carbonation product DHKUST-1 on the physiology and transcription level of the algae. A suite of advanced material characterization techniques has been utilized to multidimensionally reveal the physicochemical properties of HKUST-1 and its carbonation product. Notably, DHKUST-1 exhibit higher stability than HKUST-1 in aqueous environments, with lower ion release. During a 96-h exposure experiment, relevant indicators such as algae density, chlorophyll-a content and antioxidant enzyme activities were measured. Additionally, an intriguing IBR model was employed to comprehensively assess the toxicity of HKUST-1 and DHKUST-1 on the antioxidant system of T. obliquus. Furthermore, an in-depth analysis was conducted on the differential gene expression changes in T. obliquus under 10 mg/L HKUST-1 stress, exploring the impact on various pathways within algal cells. Briefly, the toxicity mechanism of HKUST-1 on T. obliquus is multi-involved. The findings of this study are expected to provide important basic data and references for the evaluation of the ecological safety of MOFs.

Fatal interactions: pneumonia in bighorn lambs following experimental exposure to carriers of Mycoplasma ovipneumoniae.

We hypothesized that bighorn sheep ewes with chronic nasal Mycoplasma ovipneumoniae carriage are the source of infection that results in fatal lamb pneumonia. We tested this hypothesis in captive bighorn ewes at two study facilities over a 5-year period, by identifying carrier ewes and then comparing lamb fates in groups that did (exposed pens) or did not (non-exposed pens) include one or more carrier ewes. Most (23 of 30) lambs born in exposed pens, but none of 11 lambs born in non-exposed pens, contracted fatal pneumonia. In addition, surviving lambs in exposed pens showed obvious signs of respiratory disease while lambs in non-exposed pens did not. In crossover experiments, individual non-carrier ewes had lambs that experienced fatal pneumonia in years when housed in exposed pens, but not in years when housed in non-exposed pens. The results of these studies clearly associate lamb pneumonia to exposure to M. ovipneumoniae carrier ewes, consistent with a necessary role for this agent in epizootic pneumonia of bighorn sheep. These data specifically highlight the role of chronic M. ovipneumoniae carriage by some bighorn ewes in the epidemiology of this population-limiting wildlife disease.IMPORTANCEBighorn sheep populations, historically important in mountain and canyon ecosystems of western North America, declined precipitously following European settlement of North America and remain depressed today. One factor contributing to these declines and lack of recovery is epizootic pneumonia caused by the bacterium Mycoplasma ovipneumoniae. This pathogen arrived with settlers' domestic sheep and goats and spilled over to infect bighorn sheep, a process that continues to this day. Bighorn losses from this disease include high rates of mortality (median, approaching 50%) of all ages of bighorn sheep on initial exposure, followed in subsequent years to decades by mortality largely limited to young lambs. The source of infection causing persistent lamb losses is the focus of the research described here. Conducting these studies on groups of captive bighorn sheep enabled demonstration of clear linkage between largely asymptomatic nasal carriage of M. ovipneumoniae by ewes and outbreaks of fatal pneumonia in lambs.

Exposure experiments and machine learning revealed that personal care products can significantly increase transdermal exposure of SVOCs from the environment.

We investigated the impacts of personal care products (PCPs) on dermal exposure to semi-volatile organic compounds (SVOCs), including phthalates, organophosphate esters, polycyclic aromatic hydrocarbons (PAHs), ultraviolet filters, and p-phenylenediamines, through an experiment from volunteers, explored the impact mechanisms of PCP ingredients on dermal exposure, and predicted the PCP effects on SVOC concentrations in human serum using machine learning. After applying PCPs, namely lotion, baby oil, sunscreen, and blemish balm, the dermal adsorption of SVOCs increased significantly by 1.63 ± 0.62, 1.97 ± 0.73, 1.91 ± 0.48, and 2.03 ± 0.59 times, respectively, probably due to the absorption effects of PCP ingredients. Ingredient tocopherol can increase dermal adsorption of SVOCs by 2.59 ± 1.60 times. PCPs can either increase or decrease the SVOC transdermal exposure risks, depending on the properties of their ingredients. Blemish balm caused the highest hazard quotient for certain SVOCs, while tris(2-chloroethyl) phosphate (TCEP) exhibited the highest hazard quotient. We predicted the SVOC concentrations in serum before and after applying PCPs based on the PCP-increased skin permeation doses and machine learning. PCPs can significantly increase the serum concentrations of PAHs with 2-3 rings and TCEP. This study first revealed that PCPs can significantly increase the dermal exposure of SVOCs from the surroundings, resulting in potentially higher health risks.

Climate Projections and Pacific Lamprey Conservation: Evidence That Larvae in Natural Conditions May Be Resilient to Climate Warming.

In many areas where larval Pacific lampreys currently rear, maximum stream temperatures may approach 27-31 °C during the next 75 years. Whether larval Pacific lampreys in natural conditions can tolerate these temperatures is unknown. To evaluate this ability, we conducted Direct Acute Exposure (DAE) experiments using simulated natural daily temperature (SNT) cycles in the laboratory and occupancy surveys in the Umatilla River (river). When evaluated relative to daily maximum temperatures, after seven days in DAE experiments, 78-100% of larvae survived in 29.1 °C, only larvae acclimated to 26.8 °C survived in 31.0 °C, and no larvae survived in 33.6 °C. Based on daily maximum temperatures, the ultimate upper incipient lethal temperature was estimated to be >30.8 °C using a time to death analysis and >32.0 °C using a percent mortality analysis. Some larvae acclimated to 31.0 °C were also able to survive four consecutive days with a daily maximum temperature of 33.6 °C. In 2018-2020, warm areas of the river experienced maximum temperatures in July and August that ranged from 27.7 to 33.9 °C, while cool areas experienced maximum temperatures <27.7 °C. Before, during and after the period of maximum temperatures each year, larvae occupied both areas. Detection probabilities ranged from 0.83 to 1.00 and were similar for each area and for all survey periods. This work suggests that ectothermic, larval Pacific lampreys in natural environments may be resilient to the water temperatures that are likely to result from climate warming. It is unclear whether relatively high but sublethal temperatures may impact the behavior, and ultimately survival, of larval Pacific lampreys.

Integrative RNA, miRNA, and 16S rRNA sequencing reveals immune-related regulation network for glycinin-induced enteritis in hybrid yellow catfish, Pelteobagrus fulvidraco ♀ × Pelteobagrus vachelli ♂.

Glycinin-induced foodborne enteritis is a significant obstacle that hinders the healthy development of the aquatic industry. Glycinin causes growth retardation and intestinal damage in hybrid yellow catfish (Pelteobagrus fulvidraco ♀ × Pelteobagrus vachelli ♂), but its immune mechanisms are largely unknown. In the current study, five experimental diets containing 0% (CK), 1.74% (G2), 3.57% (G4), 5.45% (G6), and 7.27% (G8) immunological activity of glycinin were fed to juvenile hybrid yellow catfish to reveal the mechanism of the intestinal immune response to glycinin through RNA and microRNA (miRNA) sequencing and to explore the interrelation between immune molecules and intestinal microbiota. The results demonstrated that glycinin content in the posterior intestine increased significantly and linearly with the rise of dietary glycinin levels. More than 5.45% of dietary glycinin significantly reduced the nutritional digestion and absorption function of the posterior intestine. Notably, an obvious alteration in the expression levels of inflammatory genes (tnf-α, il-1β, il-15, and tgf-β1) of the posterior intestine was observed when dietary glycinin exceeded 3.57%. Sequencing results of RNA and miRNA deciphered 4,246 differentially expressed genes (DEGs) and 28 differentially expressed miRNAs (DEmiRNAs) between the CK and G6 groups. Furthermore, enrichment analysis of DEGs and DEmiRNA target genes exhibited significant responses of the MAPK, NF-κB, and WNT pathways following experimental fish exposure to 5.45% dietary glycinin. Additionally, at the level of 3.57% in the diet, glycinin obviously inhibited the increase of microbiota, especially potential probiotics such as Ruminococcus bromii, Bacteroides plebeius, Faecalibacterium prausnitzii, and Clostridium clostridioforme. In sum, 5.45% dietary glycinin through the MAPK/NF-κB/WNT pathway induces enteritis, and inflammatory conditions could disrupt micro-ecological equilibrium through miRNA secreted by the host in hybrid yellow catfish. This study constitutes a comprehensive transcriptional perspective of how intestinal immunity responds to excessive glycinin in fish intestines.

Stress Granule Induction in Rat Retinas Damaged by Constant LED Light.

Stress granules (SGs) are cytoplasmic biocondensates formed in response to various cellular stressors, contributing to cell survival. Although implicated in diverse pathologies, their role in retinal degeneration (RD) remains unclear. We aimed to investigate SG formation in the retina and its induction by excessive LED light in an RD model. Rat retinas were immunohistochemically analyzed for SG markers G3BP1 and eIF3, and SGs were also visualized by RNA fluorescence in situ hybridization. Additionally, SGs were induced in primary retinal cell and eyeball cultures using sodium arsenite. Light exposure experiments used LED lamps with a color temperature of 5500 K and 200 lux intensity for short-term or two- to eight-day exposures. SGs were predominantly detected in retinal ganglion cells (RGCs) and inner nuclear layer (INL) cells, with arsenite-induction verified in RGCs. SG abundance was higher in animals exposed to light for 2-8 days compared to light/dark cycle controls. RGCs consistently exhibited more SGs than INL cells, and INL cells more than outer nuclear layer (ONL) cells (Scheirer-Ray-Hare test: H = 13.2, P = 0.0103 for light condition, and H = 278.2, P < 0.00001 for retinal layer). These observations were consistent across four independent experiments, each with three animals per light condition. This study characterizes SGs in the mammalian retina for the first time, with increased prevalence after excessive LED light exposure. RGCs and INL cells showed heightened SG formation, suggesting a potential protective mechanism against photodamage. Further investigations are warranted to elucidate the role of SGs in shielding against light stress and their implications in retinopathies.

Understanding the Molecular Mechanisms of Pyrene in Governing the Critical Metabolic Circuits of Alexandrium pacificum.

Pyrene, a representative polycyclic aromatic hydrocarbon, frequently occurs in aquatic environments and is associated with lethal impacts on humans and wildlife. This study examined the impact of pyrene on Alexandrium pacificum, a dinoflagellate responsible for harmful algal blooms, and their capability to bioremove pyrene. In a 96 h exposure experiment, A. pacificum effectively reduced the pyrene concentration in seawater to 50, 100, and 200 μg/L, with a combined removal efficiency of 96% in seawater. Furthermore, the study noted a significant reduction in the synthesis of GTX4, GTX1, NEO, and GTX3 toxins in A. pacificum cells exposed to 50 and 200 μg/L of pyrene. Concurrently, exposure to pyrene resulted in marked declines in the growth and photosynthetic efficiency of A. pacificum. Proteomics analysis results showed an upregulation of proteins related to endocytosis, such as HSPA and Arf, while proteins associated with paralytic shellfish toxin (PST) synthesis, specifically SxtU and SxtH, showed a downregulation trend. In summary, the findings of this study preliminarily elucidate the molecular mechanisms underlying A. pacificum's response to pyrene, reveal the impact of pyrene on PST synthesis, and suggest that A. pacificum holds significant potential for pyrene biodegradation.

The Space Radiobiological Exposure Facility on the China Space Station.

The Space Radiobiological Exposure Facility (SREF) is a general experimental facility at the China Space Station for scientific research in the fields of space radiation protection, space radiation biology, biotechnology, and the origin of life. The facility provides an environment with controllable temperatures for experiments with organic molecules and model organisms such as small animals, plant seeds, and microorganisms. The cultivation of small animals can be achieved in the facility with the use of microfluidic chips and images and videos of such experiments can be captured by microscopy. SREF also includes a linear energy transfer (LET) detector, neutron detectors, and a solar ultraviolet (UV) detector to measure the LET spectrum of the charged particles, energy spectrum and dose equivalent of neutrons, and fluence of solar UV radiation, respectively. The facility is reusable, and the model organisms from the first exposure experiment were recovered in orbit and returned to the ground for further study.

Assessing Heat Resistance and Selecting Heat-Resistant Individuals of Largemouth Bass (Micropterus salmoides) with Tiered Thermal Exposure.

Largemouth bass (LMB, Micropterus salmoides), a commercially important farmed fish, is vulnerable to heat stress. Breeding heat-resistant LMB is highly desirable in the face of global warming. However, we still lack an efficient method to assess the heat resistance of LMB. In this study, the critical thermal maximum (CTmax) and static exposure methods were first performed to assess the heat resistance of LMB juveniles. The CTmax values of the experimental fish (average body weight 9.87 ± 3.14 g) ranged from 39 to 40 °C but were too close together to differentiate the individual heat resistance. Static exposure experiments with varying temperatures and fish groups also did not provide a clear method for determining the heat resistance. To address these limitations, we developed a tiered exposure method, where the temperature was increased step-wise, starting from 28 to 34 °C at 2 °C increments and then at 0.5 °C increments above 34 °C, with each step lasting one day. The heat resistance of the fish was quantified as the lethal cumulative temperature (LCT), allowing for the classification of fish as sensitive or resistant to heat stress based on their LCT values. To correlate the changes in tissue structure and gene expression with the heat resistance, a new batch of LMB juveniles (average body weight 23.66 ± 6.98 g) were subjected to tiered heat exposure. Brain and liver tissues were collected from the control (without heat exposure), resistant and sensitive (still alive but demonstrated abnormal symptoms) individuals when the temperature was maintained at 35.5 °C for 24 h. The liver tissues of the heat-sensitive individuals showed significant damage and increased cell apoptosis (p < 0.05) relative to those of the resistant ones. The ddit3/chop, bax and casp3 genes demonstrated differential expressions in the liver of the sensitive and resistant fish. Additionally, the LMB juveniles (average body weight 84.06 ± 20.95 g) were found to be more heat resistant than the adults from different sources (average body weight 364.29 ± 84.43 g and 545.71 ± 184.56 g). Through the tiered exposure method, extremely heat-resistant individuals were successfully selected from the population (average body weight 22.69 ± 6.89 g). These findings provide valuable insights into the thermal biology of LMB and the potential for breeding heat-resistant LMB varieties.

The Spoilers of Virtual War: Experience and Performance Mediate the Relationship Between Violent Video Games and Hostility.

A substantial portion of the literature investigating whether playing video games with violent content causes aggressive thoughts, feelings, and behaviors has relied on experimental exposure to video game violence. To date, there is significant evidence suggesting these concepts are positively related, while other experiments demonstrate a null effect. A potential explanation for these contradicting findings is a failure to account for confounding such as video game performance and video game experience. This was examined across two experiments in which dyads played a violent video game and then completed state measures of hostility and positive and negative affects. Players with superior performance and greater gaming experience reported less hostility, less negative affect, and more positive affect. Mediation models showed that experience reduced hostility indirectly through performance. Historically, concern for hostility was greatest for frequent players, however, the current evidence suggests that these two variables should be accounted for prior to drawing conclusions. More broadly, future research might benefit by considering the phenomenology of gameplay in research on the risks and benefits of this hobby.