Persistent organic pollutants (POPs) in agricultural soil often triggered metabolic alterations and phytotoxicity in plants, ultimately threatening crop quality. Unraveling the phytotoxic mechanisms of POPs in crops is critical for evaluating their environmental risks. Herein, the molecular mechanism of POP-induced phytotoxicity in rice (Oryza sativa L.) was analyzed using metabolic profile, enzyme activity, and gene expression as linkages, including polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers, polychlorinated biphenyls, and phthalate esters. Despite no observable changes in phenotypic traits (e.g., biomass and length of aboveground), the levels of reactive oxygen species (ROS) were promoted under stresses of the tested POPs, particularly 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), dibutyl phthalate (DBP), and di(2-ethylhexyl) phthalate (DEHP). Metabolomics analysis revealed that ROS contents positively correlated with metabolic perturbation levels (r = 0.83), among which the galactose metabolism was significantly inhibited when exposed to DBP, DEHP, or BDE-47. The α-Galactosidase (α-Gal) involved in galactose metabolism was targeted as the key enzyme for the phytotoxicity of DBP, DEHP, and BDE-47, which was revealed by the inhibition of saccharide levels (45.5-82.1%), the catalytic activity of α-Gal (18.5-24.3%), and the gene expression (28.5-34.5%). Molecular docking simulation suggested that the three POPs occupied the active sites of α-Gal and formed a stable protein-ligand complex, thus inhibiting the catalytic activity of α-Gal. Partial least-squares regression analysis indicated that α-Gal activity was negatively associated with hydrogen bond acceptor, rotatable bond, and topological polar surface area of POPs. The results offered novel insights into the molecular mechanisms of phytotoxicity of POPs and provided important information for evaluating the environmental risk of POPs.
Despite the good hemodynamic characteristics of bioprosthetic heart valves, it is inevitable that they will suffer from calcification and tissue deterioration. Decellularization has been utilized to reduce the immunogenicity and calcification of bioprosthetic heart valves. However, it can take several days or even weeks to obtain the decellularized tissues or organs. Therefore, time-frame should be taken into consideration during the decellularization process. A detergent-enzymatic-method, combined with vacuum, has been proposed as a method of obtaining desirable decellularized heart valves. In this study, heart valves treated under vacuum and normal atmosphere are investigated via histological, biochemical and mechanical analysis. The results show that the decellularization efficiency of heart valves treated under vacuum is enhanced, based on histological staining, DNA contents and α-Gal quantification. The decellularization procedures decrease the contents of the extracellular matrix. However, the mechanical properties, including elastic modulus, fracture tensile strength and fracture strain, show no significant difference between the samples. In vitro cell cytotoxicity experiments indicate the feasibility of further in vivo experiments. Therefore, we conclude that vacuum-assisted decellularization procedures can significantly enhance decellularization efficiency by reducing the decellularization time, without compromising the properties of the heart valves, which is also beneficial in terms of reducing clinical costs. To the best of our knowledge, vacuum is a novel parameter which can be designed into decellularization procedures for heart valves.
Journal of biomedical materials research. Part A •
Decellularization treatment has been widely used to decrease the potential immunogenicity and improve the anticalcification properties of bio-derived materials, which may be utilized as an alternative method for the preparation of bioprosthetic heart valves. However, the excessive decellularization treatments will deteriarate the properties of heart valves. Among the decellularizaton parameters, detergent concentration and processing time are considered as those of the most key factors. Therefore, it should be meaningful to balance the decellularization efficiency and properties of bioprosthetic heart valves by optimizing the detergent concentration and processing time. In this study, three groups of the decellularized heart valves treated by sodium deoxycholate (SD) with different concentration and processing time were investigated through histological, biochemical, and mechanical analysis. Similar decellularization efficiency can be concluded through histological staining, DNA and α-Gal quantification results. Extracellular matrix contents quantification and tensile test results revealed that there is no obvious difference among the three decellularized heart valves. in vitro cytotoxicity assay showed that the remnant detergent is not enough to cause cell death, which indicated that the decellularized porcine aortic heart valves may be suitable for further in vivo research. In conclusion, Triton X-100/SD may be a suitable protocol used for heart valves decellularization. And it is feasible to vary the detergent processing time by changing the detergent concentration without compromising the decellularization efficiency.
