Changes in Induced-Antipredation Defense Traits and Transcriptome Regulations of Daphnia magna in Response to 5-HT1A Receptor Antagonist.

The serotonin signaling system plays a crucial role in regulating the ontogeny of crustaceans. Here, we describe the effects of different concentrations of the 5-hydroxytryptamine 1A receptor antagonist (WAY-100635) on the induced antipredation (Rhodeus ocellatus as the predator), morphological, behavioral, and life-history defenses of Daphnia magna and use transcriptomics to analyze the underlying molecular mechanisms. Our results indicate that exposure to WAY-100635 leads to changes in the expression of different defensive traits in D. magna when faced with fish predation risks. Specifically, as the length of exposure to WAY-100635 increases, high concentrations of WAY-100635 inhibit defensive responses associated with morphological and reproductive activities but promote the immediate negative phototactic behavioral defense of D. magna. This change is related to the underlying mechanism through which WAY-100635 interferes with gene expression of G-protein-coupled GABA receptors by affecting GABBR1 but promotes serotonin receptor signaling and ecdysteroid signaling pathways. In addition, we also find for the first time that fish kairomone can significantly activate the HIF-1α signaling pathway, which may lead to an increase in the rate of immediate movement. These results can help assess the potential impacts of serotonin-disrupting psychotropic drugs on zooplankton in aquatic ecosystems.

Differential interference effects of thermal pollution on the induced defense of different body-sized cladocerans.

Climate warming influences the biological activities of aquatic organisms, including feeding, growth, and reproduction, thereby affecting predator-prey interactions. This study explored the variation in thermal sensitivity of anti-predator responses in two cladoceran species with varying body sizes, Daphnia pulex and Ceriodaphnia cornuta. These species were cultured with or without the fish (Rhodeus ocellatus) kairomone at temperatures of 15, 20, 25, and 30 °C for 15 days. Results revealed that cladocerans of different body sizes exhibited varying responses to fish kairomones in aspects such as individual size, first-brood neonate size, total offspring number, average brood size, growth rate, and reproductive effort. Notably, low temperature differently affected defense responses in cladocerans of different body sizes. Both high and low temperatures moderated the intensity of the kairomone-induced response on body size at maturity. Additionally, low temperature reversed the reducing effect of fish kairomone on the total offspring number, average brood size, and reproductive effort in D. pulex. Conversely, it enhanced the increasing effect of fish kairomone on these parameters in C. cornuta. These results suggest that inducible anti-predator responses in cladocerans are modifiable by temperature. The differential effects of fish kairomones on various cladocerans under temperature influence offer crucial insights for predicting changes in predator-prey interactions within freshwater ecosystems under future climate conditions.

Herbicide atrazine impairs metabolic plasticity of mixotrophic organisms: Evidence in photochemistry, morphology, and gene expression.

Herbicide pollution is a main form of water pollution. As a result of additional harms to other non-target organisms, it threatens the function and structure of ecosystems. Previous researches mainly focused on the assessment of the toxicity and ecological effect of herbicides on monotrophic organisms. Responses of mixotrophs as an important component of functional groups are rarely understood in contaminated waters, although their metabolic plasticity and unique ecological functions in ecosystem stability are a major concern. This work aimed to investigate the trophic plasticity of mixotrophic organisms in atrazine-contaminated waters, and a primarily heterotrophic Ochromonas was used as the tested organism. Results showed that the herbicide atrazine significantly inhibited the photochemical activity and impaired the photosynthetic machine of Ochromonas, and photosynthesis activated by light was sensitive to atrazine. However, phagotrophy was unaffected by atrazine and closely correlated with growth rate, indicating that heterotrophy helped population maintenance during herbicide exposure. Mixotrophic Ochromonas upregulated the gene expression level involved in photosynthesis, energy synthesis, and antioxidation to adapt to increasing atrazine after long-term exposure. Compared with bacterivory, herbivory increased atrazine tolerance of photosynthesis under mixotrophic status. This study systematically illustrated the mechanism by which mixotrophic Ochromonas respond to the herbicide atrazine at population, photochemical activity, morphology, and gene expression levels and demonstrated the potential effect of atrazine on the metabolic flexibility and ecological niches of mixotrophs. These findings will provide important theoretical reference for governance and management decision-making in contaminated environments.

A population-based cohort study for presence of ulceration among cutaneous malignant melanoma subgroups of patients.

Background: Observational studies suggest that ulceration is considered to be a negative prognostic factor for cutaneous melanoma. However, the impact of ulceration over different subgroups (e.g. AJCC Stage, thickness level) are controversial and its true causal effect on survival is lack of studies in the view of treating ulceration as an exposure. Objective: To explore the true causal effect of ulceration on melanoma's survival by adopting a combination of methods to discover proper adjustment set and confirming its correctness through a variety of means. Methods: A minimal sufficient adjustment set (MSAS) was found using directed acyclic graphs (DAG) to adjust the effect of causality. Sensitivity analysis was conducted to diagnose potential confounders in addition to MSAS. Cox models were built to analyze the causality in-depth and the model was validated using a novel method. Lastly, stratified effects of ulceration were examined to illustrate its impact within subgroups. Results: Hazard ratio (HR) of ulceration after adjustment by MSAS variables was 1.99 (95% CI=1.88-2.09). The sensitivity analysis of propensity score matching and E-value both demonstrated that variables other than MSAS do not have great influence on ulceration and MSS relationship. The HR of ulceration in AJCC Stage, thickness level, invasion level and tumor extension were all monotonically decreased from 5.76 to 1.57, 4.03 to 1.78, 2.75 to 1.78 and 2.65 to 1.71 respectively. Conclusion: Ulceration in all subgroups were shown to have a significantly negative impact on MSS and its magnitude of effect was monotonically decreased as the disease progressed. The true effect of ulceration can be adjusted by MSAS and its correctness was validated through a variety of approaches.

Health risk assessment using in vitro simulation in assessing bioavailability of cadmium in rice from main producing areas across China.

Rice is a recognized source of cadmium (Cd) exposure. In this study, a total of 102 rice samples were obtained from main producing rice regions of China, and the bioavailability of Cd in rice were assessed by using an in vitro digestion method combined with a Caco-2 cell monolayer model. The results revealed that the average (range of) concentration of Cd in the rice samples was 0.2840 (0.0123-2.4710) mg/kg, and the average (range of) bioavailability of Cd in the rice samples was 23.94% (7.47-39.73%). We analyzed the recent rice consumption data and calculated the target hazard quotients (THQs) to evaluate the noncarcinogenic health risk of Cd in rice consumption for adults and children, respectively. We suggested that the most of investigated regions showed low risks of Cd in rice for general population, and the regions of Cd in rice near the limit deserves might be attracted more attention after taking bioavailability into account. PRACTICAL APPLICATION: The cadmium content of rice itself will affect its corresponding bioavailability to a certain extent. By studying the in vitro bioavailability of cadmium rice with different pollution levels, it is helpful for the dose selection of animal experiments or toxicity tests, and finally, we may provide some references for the establishment of appropriate treatment scheme of rice Cd poisoning.

Study on the bioaccessibility and bioavailability of Cd in contaminated rice in vitro and in vivo.

Cadmium (Cd) is a widespread heavy metal pollutant in the environment that damages human health. In this study, the bioaccessibility and bioavailability of Cd in different Cd-contaminated rice (low pollution level cadmium rice (Rice-L, 0.111 mg/kg), medium pollution level cadmium rice (Rice-M, 0.400 mg/kg), and high pollution level cadmium rice (Rice-H, 0.655 mg/kg)) were estimated and determined by an in vitro digestion model Rijksinstituut voor volksgezondheiden milieu (RIVM), Caco-2 cell model, and mouse model. The results indicated that Cd in the oral cavity (15.65-28.28%) displayed the lowest bioaccessibility comparing with small intestine (90.04-94.73%) and the stomach (99.30-100.70%) in vitro after cooking. In addition, the results showed that the bioaccessibility of Cd in CdCl2 , CdCl2 +normal rice (Rice-N), Rice-H, Rice-M, Rice-L group were 99.29%, 92.57%, 90.04%, 94.73%, and 91.11%, respectively; the in vitro bioavailability of Cd in CdCl2 , CdCl2 +Rice-N, Rice-H, Rice-M, and Rice-L group were 27.50%, 20.78%, 21.90%, 26.90%, 36.46%, respectively, we found that the group of CdCl2 is significantly higher than CdCl2 +Rice-N and Rice-H (p < 0.05), while the targets hazard quotient (THQ) value of rice ingested without considering the in vitro bioavailability is 2.7-4.6 times than the THQ value with considered and the relative bioavailability (RBA) of Cd in Rice-L, Rice-M, Rice-H are 80.25%, 64.32%, and 60.91%, respectively. These results indicate that the rice substrate has impact on the bioaccessibility and bioavailability of Cd, and might overestimate the health risks of Cd if bioavailability was not considered. PRACTICAL APPLICATION: Studying the bioaccessibility and bioavailability of cadmium in rice is a promising strategy to obtain a more accurate human health risk assessment of cadmium exposure in rice, as well as provide a theoretical basis for the formulation of cadmium limit standard in grain, which was also conducive to the rational and full utilization of rice resources in China.

Highly sensitive determination of 4-nitrophenol with coumarin-based fluorescent molecularly imprinted poly (ionic liquid).

A coumarin-based fluorescent molecularly imprinted poly (ionic liquid) (FL-MIPIL) was prepared using a new coumarin-based alkenyl fluorescent ionic liquid (coumarin-FL-IL) as the functional monomer, IL [V2C4(mim)2][(PF6)2] and ethyleneglycol dimethacrylate as the cross-linkers, and 4-NP as the template molecule. The absolute quantum yields of coumarin-FL-IL and FL-MIPIL were 7.26 % and 30.66 %, respectively. As a result of the electron transfer between coumarin-FL-IL which contains amino groups and 4-NP bearing hydroxyl groups, FL-MIPIL fluorescence was effectively quenched by 4-NP. The prepared FL-MIPIL sensor can rapidly respond to 4-NP within 60 s. The FL-MIPIL sensor had good linear response to 4-NP from 0.001-7.5 µM and low detection limit of 0.5 nM (S/N = 3). The FL-MIPIL sensor exhibited high sensitivity and good selectivity for 4-NP. The outstanding performance of FL-MIPIL could be ascribed to high fluorescence intensity of FL-MIPIL without matrixes and more interactions between FL-MIPIL and 4-NP. The FL-MIPIL sensor has successfully applied to the determination of 4-NP in lake, rain and waste water samples, river sediment, soil and urine samples.

The phase transfer effect of sulfur in lithium-sulfur batteries.

Lithium-sulfur (Li-S) batteries are considered to be among the most promising energy storage technologies owing to their high theoretical capacity (1675 mA h g-1). At present, however, discharge mechanisms are complicated and remain a controversial issue. In this work, elemental sulfur, used as an electrical insulator for the cathode, was introduced into batteries for its potential chemical reactions in the electrolyte. A film, prepared by loading elemental sulfur onto glass fiber, was introduced as an interlayer in a Li-S battery. The results demonstrate that elemental sulfur may be reduced to polysulfides even when it functions as an electrical insulator for the cathode. Furthermore, it can improve the overall capacity of the Li-S battery and cycle life. This was verified by simulating the phase equilibrium of the chemical system in Li-S batteries using HSC Chemistry software. We hypothesize that the insulating elemental sulfur could be reduced by polysulfides generated on the cathode, after which they are dissolved in the electrolyte and participate in cathode reactions. This phase transfer effect of sulfur in Li-S batteries revealed a chemical equilibrium in the electrolyte of the Li-S battery, which may form a chemical path embedded into the discharge process of Li-S batteries.