Phenylpropanoid metabolic pathway is one of the most important secondary metabolic pathways in plants. It directly or indirectly plays an antioxidant role in plant resistance to heavy metal stress, and can improve the absorption and stress tolerance of plants to heavy metal ions. In this paper, the core reactions and key enzymes of the phenylpropanoid metabolic pathway were summarized, and the biosynthetic processes of key metabolites such as lignin, flavonoids and proanthocyanidins and relevant mechanisms were analyzed. Based on this, the mechanisms of key products of phenylpropanoid metabolic pathway in response to heavy metal stress were discussed. The perspectives on the involvement of phenylpropanoid metabolism in plant defense against heavy metal stress provides a theoretical basis for improving the phytoremediation efficiency of heavy metal polluted environment.
Plants/metabolism* ; Metals, Heavy/metabolism* ; Flavonoids/metabolism* ; Biodegradation, Environmental ; Antioxidants

This study explored whether Sagittaria sagittifolia polysaccharides(SSP) activates the nuclear factor erythroid-2-related factor2(Nrf2)/heme oxygenase-1(HO-1) signaling pathway to protect against liver damage jointly induced by multiple heavy metals. First, based on the proportion of dietary intake of six heavy metals in rice available in Beijing market, a heavy metal mixture was prepared for inducing mouse liver injury and HepG2 cell injury. Forty male Kunming mice were divided into five groups: control group, model group, glutathione positive control group, and low-and high-dose SSP groups, with eight mice in each group. After 30 days of intragastric administration, the liver injury in mice was observed by HE staining. In the in vitro experiment, MTT assay was conducted to detect the effects of SSP at 0.25, 0.5, 1, and 2 mg·mL~(-1) on HepG2 cell survival at different time points. The content of alanine transaminase(ALT) and aspartate aminotransferase(AST) in the 48-h cell culture fluid was measured using micro-plate cultivation method, followed by the detection of the change in reactive oxygen species(ROS) content by flow cytometry. The mRNA expression levels of Nrf2 and HO-1 in cells were determined by RT-PCR, and their protein expression by Western blot. HE staining results showed that compared with the model group, the SSP administration groups exhibited significantly alleviated inflammatory cell infiltration and fatty infiltration in the liver, with better outcomes observed in the high-dose SSP group. In the in vitro MTT assay, compared with the model group, SSP at four concentrations all significantly increased the cell survival rate, decreased the ALT, AST, and ROS content(P<0.05), and down-regulated Nrf2 and HO-1 mRNA and protein expression(P<0.05). SSP significantly improves inflammatory infiltration in the liver tissue of mice exposed to a variety of heavy metals and corrects the liver fat degeneration, which may be related to its regulation of the Nrf2/HO-1 signaling pathway, reduction of ROS, and alleviation of oxidative damage.
Animals ; Heme Oxygenase-1/metabolism* ; Liver ; Male ; Metals, Heavy/metabolism* ; Mice ; NF-E2-Related Factor 2/metabolism* ; Oxidative Stress ; Polysaccharides/pharmacology* ; RNA, Messenger/metabolism* ; Reactive Oxygen Species/metabolism* ; Sagittaria/metabolism*

P1B-ATPases are a group of proteins that can transport heavy metal ions across membranes by hydrolyzing ATP and they are a subclass of the P-type ATPase family. It was found that P1B-ATPases are mainly responsible for the active transport of heavy metal ions in plants and play an important role in the regulation of heavy metal homeostasis in plants. In this paper, we dissusses the mechanism of P1B-ATPases from the structure and classification of P1B-ATPases, and review the current research progress in the function of P1B-ATPases, in order to provide reference for future research and application of P1B-ATPases in improving crop quality and ecological environment management.
Adenosine Triphosphatases/metabolism* ; Biological Transport ; Metals, Heavy ; Plants/enzymology*

BACKGROUND: Placenta previa and placenta accreta associate with high morbidity and mortality for both mothers and fetus. Metal exposure may have relationships with placenta previa and placenta accreta. This study analyzed the associations between maternal metal (cadmium [Cd], lead [Pb], mercury [Hg], selenium [Se], and manganese [Mn]) concentrations and placenta previa and placenta accreta. METHODS: We recruited 17,414 women with singleton pregnancies. Data from a self-administered questionnaire regarding the first trimester and medical records after delivery were analyzed. Maternal blood samples were collected to measure metal concentrations. The subjects were classified into four quartiles (Q1, Q2, Q3, and Q4) according to metal concentrations. RESULTS: The odds ratio for placenta previa was significantly higher among subjects with Q4 Cd than those with Q1 Cd. The odds ratio for placenta previa was significantly higher for subjects with Q2 Pb than those with Q1 Pb. CONCLUSION Participants with placenta previa had higher Cd concentrations. However, this study was cross-sectional and lacked important information related to Cd concentration, such as detailed smoking habits and sources of Cd intake. In addition, the subjects in this study comprised ordinary pregnant Japanese women, and it was impossible to observe the relationship between a wide range of Cd exposure and placenta previa. Therefore, epidemiological and experimental studies are warranted to verify the relationship between Cd exposure and pregnancy abnormalities.
Adult ; Cross-Sectional Studies ; Female ; Humans ; Japan ; Metals, Heavy ; blood ; metabolism ; Placenta Accreta ; metabolism ; Placenta Previa ; metabolism ; Pregnancy ; Selenium ; blood ; metabolism

With the increasing occurrence of haze during the summer, the physicochemical characteristics and toxicity differences in PM_2.5 in different seasons are of great concern. Hangzhou is located in an area that has a subtropical monsoon climate where the humidity is very high during both the summer and winter. However, there are limited studies on the seasonal differences in PM_2.5 in these weather conditions. In this test, PM_2.5 samples were collected in the winter and summer, the morphology and chemical composition of PM_2.5 were analyzed, the toxicity of PM_2.5 to human bronchial cells BEAS-2B was compared, and the correlation between PM_2.5 toxicity and the chemical composition was discussed. The results showed that during both the winter and summer, the main compounds in the PM_2.5 samples were water-soluble ions, particularly SO₄^2-, NO₃^-, and NH₄⁺, followed by organic components, while heavy metals were present at lower levels. The higher the mass concentration of PM_2.5, the greater its impact on cell viability and ROS levels. However, when the mass concentration of PM_2.5 was similar, the water extraction from the summer samples showed a greater impact on BEAS-2B than that from the winter samples. The cytotoxicity of PM_2.5 was closely associated with heavy metals and organic pollutants but less related to water-soluble ions.
Air Pollutants/toxicity* ; Bronchi/metabolism* ; Carbon/chemistry* ; Environmental Monitoring ; Humans ; Ions ; Metals, Heavy ; Organic Chemicals ; Particle Size ; Particulate Matter/toxicity* ; Seasons ; Temperature ; Water

OBJECTIVEAssessment of the bacterium L. sphaericus as a dual-action candidate for biological control of mosquito-borne diseases and bioremediation of toxic metals.

METHODSLarvae of the mosquito, C. quinquefasciatus, were first evaluated for metal tolerance and then exposed to 5 ppm cadmium, chromium, arsenic, and lead in assays together with seven strains of L. sphaericus. A probit regression analysis was used to estimate the LC(50) of Cd, Cr, As, and Pb to C. quinquefasciatus. An analysis of covariance and multifactorial ANOVA examined the metal biosorption and larvicidal properties of the seven strains of L. sphaericus.

RESULTSWe found that L. sphaericus adsorbed the toxic metal ions and was toxic against mosquito larvae. The L. sphaericus strain III(3)7 resulted in a larvae mortality of over 80% for all the tested metals. This strain also exhibited the capacity to adsorb 76% of arsenic, 32% of lead, 25% of chromium, and 7% of cadmium.

CONCLUSIONThis study found combined metal adsorption and larval toxicity associated with three strains of L. sphaericus [III(3)7, OT4b.31, and CBAM5]. This suggests that a combination of these strains shows strong dual potential for biological control of mosquitos in heavy metal-contaminated areas and remediate the heavy metal contamination as well.

Animals ; Bacillaceae ; physiology ; Culicidae ; microbiology ; Host-Pathogen Interactions ; Insect Vectors ; Larva ; microbiology ; Metals, Heavy ; metabolism ; toxicity ; Water Pollutants, Chemical ; metabolism ; toxicity

In this study, we investigate the bioaccessibility of heavy metals (Cu, Pb, As, Cd and Hg) in wild Artemisia annua and use target hazard quotients (THQ) proposed by US Environmental Protection Agency to assess the health risk under the heavy metal exposure. The results showed that the bioaccessibility of Cu, Pb, As, Cd and Hg in A. annua are 0.77, 0.66, 0.46, 0.68 and 0, respectively, and that the value of THQ for adults and children were 0.030 and 0.025 calculated by risk assessment model. The results indicated that the heavy metals in A. annua were not able to be completely absorbed by human body and that their contents were in a safe range. In this study, by combining the bioavailability of heavy metal and health risk assessment, we assessed the security of heavy metals of wild A. annua, which will provide reference for the standard of heavy metals for medicinal materials.
Artemisia annua ; chemistry ; metabolism ; Consumer Product Safety ; Drug Contamination ; Humans ; Metals, Heavy ; analysis ; metabolism ; Risk Assessment ; Soil Pollutants ; analysis ; metabolism

One of the causes of the high cost of pharmaceuticals and the major obstacles to rapidly assessing the bioavailability and risk of a chemical is the lack of experimental model systems. A new pre-treatment technology, in vitro bionic digestion was designed for metal analysis in Lianhua Qingwen capsule. The capsule was digested on 37 degrees C under the acidity of the stomach or intestine, and with the inorganic and organic compounds (including digestive enzymes) found in the stomach or intestine, and then the chyme was obtained. Being similar to the biomembrane between the gastrointestinal tract and blood vessels, monolayer liposome was used as biomembrane model Affinity-monolayer liposome metals (AMLMs) and water-soluble metals were used for metal speciation analysis in the capsule. Based on the concentration of AMLMs, the main absorption site of trace metals was proposed. The metal total contents or the concentration of AMLMs in the capsule were compared to the nutritional requirements, daily permissible dose and heavy metal total contents from the "import and export of medicinal plants and preparation of green industry state standards". The metal concentrations in the capsule were within the safety baseline levels for human consumption. After in vitro bionic digestion, most of trace metals were absorbed mainly in intestine. The concentration of As, Cd, Pb was 0.38, 0.07, 1.60 mg x kg(-1), respectively, far less than the permissible dose from the "import and export of medicinal plants and preparation of green industry state standards".
Biological Availability ; Capsules ; adverse effects ; pharmacokinetics ; Digestion ; Drugs, Chinese Herbal ; adverse effects ; pharmacokinetics ; Humans ; Metals, Heavy ; adverse effects ; pharmacokinetics ; Models, Biological ; Stomach ; metabolism ; Trace Elements ; adverse effects ; pharmacokinetics

Six heavy metals, including As, Cu, Hg, Cd, Pb and Cr in Panax notoginseng were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) combined with wet digestion method. The samples of P. notoginseng were collected in 12 different regions, including Yunnan and Guangxi Province. Green Standards of Foreign Trading Medicinal Plants & Preparations was used as the standard to evaluate the pollution status of As, Cu, Hg, Cd, Pb and Cr in P. notoginseng. The results showed that content of As and Cd exceeded the limit of the standard and the percentage was 32.4% and 29.7%, respectively, while Cu, Hg and Pb were all bellow the limit. The SPSS 16.0 software was used to analyze the data. The occurrence of contained heavy metals has been discussed.
China ; Drug Contamination ; Drugs, Chinese Herbal ; analysis ; Metals, Heavy ; analysis ; metabolism ; Panax notoginseng ; chemistry ; metabolism ; Soil Pollutants ; analysis ; metabolism

We cloned the lipoxygenase gene (ana-LOX) from Anabaena sp. PCC 7120 and expressed it in Escherichia coli BL21 (DE3) pLysS. We determined the active site of the recombinant ana-LOX through site-directed gene mutagenesis and obtained the shortest length of the functional gene. Meanwhile, we studied the properties of recombinant ana-LOX after purification. The C-terminal of the Aos (allene oxide synthase)-LOX fusion gene in Anabaena sp. PCC 7120 genome was found belonging to LOXs family by bioinformatics analysis. Further results of site-directed gene mutagenesis confirmed that the active sites of ana-LOX were His197, His202, His369, Asn373and Ile455. The shortest length of functional gene was identified to be 1 254 bp based on the strategy of shortening the gene length gradually. The highest activity of recombinant ana-LOX of 6 750 U/mL could be achieved when constructed to pET-32a vector and expressed at low temperature 16 degrees C. We purified the enzyme by Ni-NTA chelating affinity chromatography, with 60.89% yield and specific activity of 11.4 x 10(4) U/mg. The optimum reaction temperature and pH for ana-LOX were 45 degrees C and 6.0, respectively. Furthermore, the obtained ana-LOX was stable at room temperature. The effect of metal ions on ana-LOX was determined also. Fe2+, Mg2+ Ca2+ could markedly promote the activity of this enzyme whereas Fe3+ and Cu2+ had a strong inhibitory effect on it. Finally, the ana-LOX could improve the microscopical structure of dough. The results of this study will provide a basis for future improvements and food industrial applications of ana-LOX.
Anabaena ; enzymology ; genetics ; Catalytic Domain ; Cloning, Molecular ; Enzyme Stability ; Escherichia coli ; metabolism ; Lipoxygenase ; chemistry ; genetics ; Metals, Heavy ; chemistry ; Mutagenesis, Site-Directed ; Recombinant Proteins ; chemistry ; genetics