Antioxidant defenses and metabolic responses of Mytilus coruscus exposed to various concentrations of PAEs (phthalate esters).

Phthalate esters (PAEs), as a major plasticizer with multi-biotoxicity, are frequently detected in marine environments, and potentially affecting the survival of aquatic organisms. In the study, three typical PAEs (dimethyl phthalate [DMP], dibutyl phthalate [DBP] and di(2-ethylhexyl) phthalate [DEHP]) were selected to investigate the accumulation patterns and ecotoxicological effects on Mytilus coruscus (M. coruscus). In M. coruscus, the accumulation was DEHP>DBP>DMP, and the bioaccumulation in tissues was digestive glands>gills>gonads>muscles. Meanwhile, the activities of superoxide dismutase (SOD) and catalase (CAT) showed an activation-decrease-activation trend of stress, with more pronounced concentration effects. Glutathione reductase (GSH) activity was significantly increased, and its expression was more sensitive to be induced at an early stage. The metabolic profiles of the gonads, digestive glands and muscle tissues were significantly altered, and DEHP had a greater effect on the metabolic profiles of M. coruscus, with the strongest interference. PAEs stress for 7 d significantly altered the volatile components of M. coruscus, with potential implications for their nutritional value. This study provides a biochemical, metabolomic, and nutritional analysis of DMP, DBP, and DEHP toxic effects on M. coruscus from a multidimensional perspective, which provides support for ecotoxicological studies of PAEs on marine organisms. ENVIRONMENTAL IMPLICATION: Phthalate esters (PAEs), synthetic compounds from phthalic acid, are widespread in the environment, household products, aquatic plants, animals, and crops, posing a significant threat to human health. However, the majority of toxicological studies examining the effects of PAEs on aquatic organisms primarily focus on non-economic model organisms like algae and zebrafish. Relatively fewer studies have been conducted on marine organisms, particularly economically important shellfish. So, this study is innovative and necessary. This study provides a biochemical, metabolomic, and nutritional analysis of DMP, DBP, and DEHP toxic effects on mussels, and supports the ecotoxicology of PAEs on marine organisms.

A Review of the Development and Challenges of Cell Mechanical Models.

Cell models can express a variety of cell information, including mechanical properties, electrical properties, and chemical properties. Through the analysis of these properties, we can fully understand the physiological state of cells. As such, cell modeling has gradually become a topic of great interest, and a number of cell models have been established over the last few decades. In this paper, the development of various cell mechanical models has been systematically reviewed. First, continuum theoretical models, which were established by ignoring cell structures, are summarized, including the cortical membrane droplet model, solid model, power series structure damping model, multiphase model, and finite element model. Next, microstructural models based on the structure and function of cells are summarized, including the tension integration model, porous solid model, hinged cable net model, porous elastic model, energy dissipation model, and muscle model. What's more, from multiple viewpoints, the strengths and weaknesses of each cell mechanical model have been analyzed in detail. Finally, the potential challenges and applications in the development of cell mechanical models are discussed. This paper contributes to the development of different fields, such as biological cytology, drug therapy, and bio-syncretic robots.

Label-free purification and characterization of optogenetically engineered cells using optically-induced dielectrophoresis.

Optogenetically engineered cell population obtained by heterogeneous gene expression plays a vital role in life science, medicine, and biohybrid robotics, and purification and characterization are essential to enhance its application performance. However, the existing cell purification methods suffer from complex sample preparation or inevitable damage and pollution. The efficient and nondestructive label-free purification and characterization of the optogenetically engineered cells, HEK293-ChR2 cells, is provided here using an optically-induced dielectrophoresis (ODEP)-based approach. The distinctive crossover frequencies of the engineered cells and the unmodified cells enable effective separation due to the opposite DEP forces on them. The ODEP-based approach can greatly improve the purity of the separated cell population and especially, the ratio of the engineered cells in the separated cell population can be enhanced by 275% at a low transfection rate. The size and the membrane capacitance of the separated cell population decreases and increases, respectively, as the ratio of the engineered cells grows in the cell population, indicating that successful expression of ChR2 in a single HEK293 cell makes its size and membrane capacitance smaller and larger, respectively. The results of biohybrid imaging with the optogenetically engineered cells demonstrated that cell purification can improve the imaging quality. This work proves that the separation and purification of engineered cells are of great significance for their application in practice.

Development and challenges of smart actuators based on water-responsive materials.

Water-responsive (WR) materials, due to their controllable mechanical response to humidity without energy actuation, have attracted lots of attention to the development of smart actuators. WR material-based smart actuators can transform natural humidity to a required mechanical motion and have been widely used in various fields, such as soft robots, micro-generators, smart building materials, and textiles. In this paper, the development of smart actuators based on different WR materials has been reviewed systematically. First, the properties of different biological WR materials and the corresponding actuators are summarized, including plant materials, animal materials, and microorganism materials. Additionally, various synthetic WR materials and their related applications in smart actuators have also been introduced in detail, including hydrophilic polymers, graphene oxide, carbon nanotubes, and other synthetic materials. Finally, the challenges of the WR actuator are analyzed from the three perspectives of actuator design, control methods, and compatibility, and the potential solutions are also discussed. This paper may be useful for the development of not only soft actuators that are based on WR materials, but also smart materials applied to renewable energy.

Probing the contamination characteristics, mobility, and risk assessments of typical plastic additive-phthalate esters from a typical coastal aquaculture area, China.

Contamination characteristics, equilibrium partitioning and risk assessment of phthalate esters (PAEs) were investigated in seawater, sediment and biological samples collected from the Xiangshan Bay area during an annual investigation between January and November 2019. PAE concentrations detected in the mariculture environment in surface seawater, sediment, and biological samples were 172-3365 ng/L, 190-2430 µg/kg (dry weight [dw]), and 820-4926 µg/kg (dw), respectively. The dominant congeners in different media included di-n-butyl phthalate (DnBP), diisobutyl phthalate (DiBP), and di(2-ethylhexyl) phthalate (DEHP). The inner bay and the bay mouth were the gathering area of PAEs and heavily influenced by the mariculture activities, river inputs, and anthropogenic activities. The bioaccumulation of PAEs demonstrated benthic feeding fishes with relatively high trophic levels concentrated high levels of phthalates. The mobility of PAEs in sediment-seawater showed that the transfer tendency of low-molecular weight species was from the sediment to the water, which was in contrast with those of high-molecular weight PAEs. DEHP, DiBP and DnBP had various degrees of ecological risks in the aquatic environment, whereas only the DiBP posed potential risks in sediments. The current assessment of carcinogenic and noncarcinogenic risks posed by fish consumption were within acceptable limits for humans.

A comprehensive study of the effects of phthalates on marine mussels: Bioconcentration, enzymatic activities and metabolomics.

In this study, marine mussels (Mytilus coruscus) were exposed to three typical PAEs (dimethyl phthalate [DMP], dibutyl phthalate [DBP] and di(2-ethylhexyl) phthalate [DEHP]) at a range of doses for different times to investigate the ecotoxicological effects. The accumulation of the three PAE congeners in M. coruscus exhibited the following trend: DEHP > DBP > DMP. The antioxidant response of mussel gonadal tissue was enhanced with increasing concentrations of PAEs. For the DBP and DEHP treatment groups, glutathione (GSH) worked in concert with antioxidant enzymes to protect cells against reactive oxygen species (ROS), while GSH played a prominent antioxidant role in the DMP-treated group. The metabolomics results revealed that PAE exposure disrupted the metabolic balance of mussels. Overall, PAEs affect the amino acid metabolism, lipid metabolism, energy metabolism, osmoregulation and nerve activities of mussels. Our results provide further insight into the toxicological effects of PAEs on marine organisms.

Comparative evaluation of high-density polyethylene and polystyrene microplastics pollutants: Uptake, elimination and effects in mussel.

The high-density polyethylene (HDPE) and the polystyrene (PS), which are typical microplastic contaminants, are frequently detected in the environment and have potential hazard to environmental health. In this study, the accumulation, elimination, tissue distribution and potential effects of the HDPE and the PS in the mussels (Mytilus galloprovincialis) were evaluated. The HDPE and the PS were found in various tissues (digestive gland > gill > gonad ≈ muscle) with no difference in distribution patterns. The accumulation of the HDPE and the PS rapidly increased in the first 48 h exposure, and the accumulation of HDPE was higher than that of PS. After 144 h of elimination, most of the HDPE and the PS were cleared by mussels. In addition, the activities of superoxide dismutase (SOD), catalase (CAT) and the content of oxidized glutathione considerably increased, indicating that the HDPE and the PS induced oxidative stress and prevented oxidative damage in elimination. The metabolomic analysis suggested that exposure to HDPE and PS induced alterations in the metabolic profiles of mussel. Differential metabolites were involved in energy metabolism, lipid metabolism, tricarboxylic acid cycle and neurotoxic response., and Meanwhile, the PS had a lower effect on mussel metabolism during elimination, but the effect of HDPE was increased. Overall, this study elucidated that the HDPE and the PS caused adverse effects on the mussels and provided insights toward understanding the hazard of different microplastics on aquatic organisms.

Contaminant occurrence, mobility and ecological risk assessment of phthalate esters in the sediment-water system of the Hangzhou Bay.

The pollution characteristics, spatiotemporal variation, sediment-water partitioning, and potential ecological risk assessment of phthalate esters (PAEs) in the sediment-seawater system of the Hangzhou Bay (HZB) in summer and autumn were researched. The sum of the concentrations of the 10 PAEs in seawater ranges from 7305 ng/L to 22,861 ng/L in summer and from 8100 ng/L to 33,329 ng/L in autumn, with mean values of 15,567 ± 4390 and 17,884 ± 6850 ng/L, respectively. The Σ16PAEs in the sediments are between 118 and 5888 µg/kg and 145 and 4746 µg/kg in summer and autumn, respectively. The level of PAEs in seawater varies with the seasons, but it is relatively stable in the sediments. Di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), and diisobutyl phthalate (DiBP) are the predominant PAE congeners in the HZB. The DnBP and DiBP concentrations in seawater are greater than the DEHP concentration, which is the opposite in the sediments. The sediment-seawater equilibrium distribution study indicates that the PAEs with medium molecular weights, such as DiBP, butyl benzyl phthalate, and DnBP, are near dynamic equilibrium in the sediment-seawater system; PAEs with high molecular weights (e.g., di-n-octyl phthalate and DEHP) tend to transfer from water to the sediments; and PAEs with low molecular weights (e.g., dimethyl phthalate, diethyl phthalate, and diamyl phthalate) tend to spread to seawater. The risk assessment results in seawater indicate that DEHP and DiBP might pose high potential risks to sensitive organisms, and DnBP might exhibit medium ecological risks. In the sediment, DiBP might display a high potential risk to fish, and the potential risk of DEHP is high in several sites.