Physiological of biochar and α-Fe2O3 nanoparticles as amendments of Cd accumulation and toxicity toward muskmelon grown in pots.

BACKGROUND: Due to the severe cadmium (Cd) pollution of farmland soil, effective measures need to be taken to reduce the Cd content in agricultural products. In this study, we added α-Fe2O3 nanoparticles (NPs) and biochar into Cd-contaminated soil to investigate physiological responses of muskmelon in the whole life cycle. RESULTS: The results showed that Cd caused adverse impacts on muskmelon (Cucumis melo) plants. For instance, the chlorophyll of muskmelon leaves in the Cd alone treatment was reduced by 8.07-32.34% in the four periods, relative to the control. The treatments with single amendment, α-Fe2O3 NPs or 1% biochar or 5% biochar, significantly reduced the soil available Cd content, but the co-exposure treatments (α-Fe2O3 NPs and biochar) had no impact on the soil available Cd content. All treatments could reduce the Cd content by 47.64-74.60% and increase the Fe content by 15.15-95.27% in fruits as compared to the Cd alone treatment. The KEGG enrichment results of different genes in different treatments indicated that single treatments could regulate genes related to anthocyanin biosynthesis, glutathione metabolism and MAPK signal transduction pathways to reduce the Cd toxicity. CONCLUSIONS: Overall the combination of biochar and α-Fe2O3 NPs can alleviate Cd toxicity in muskmelon. The present study could provide new insights into Cd remediation in soil using α-Fe2O3 NPs and biochar as amendments.

A study on the mixture repairing effect of biochar and nano iron oxide on toxicity of Cd toward muskmelon.

Soil contamination with cadmium (Cd) has become a serious problem, adversely affecting food safety and human health. Effective methods are urgently needed to alleviate toxicity of Cd in plants. In this study, a nine-week continuous pot experiments was conducted to explore the effectiveness of the different nano iron oxide (α-Fe2O3, γ-Fe2O3, Fe3O4) alone and combined with biochar in muskmelon grown on a Cd-contaminated soil. The antioxidant system, chlorophyll, soluble protein, other physiological indexes of muskmelon leaves and the distribution of Cd in matrix soil, leaves and fruit were detected. The results showed that Cd was readily absorbed by plants and caused oxidative stress on plants, while biochar, α-Fe2O3 nanoparticles (NPs) and their mixture group (BFe1 group) could significantly improve it. Specifically, the three treatments reduced the Cd content of the fruit by 19.51-78.86%, reduced the Cd content of leaves by 15.44-36.23% and 22.36-31.77% in weeks 3 and 5, respectively. For the activity of enzymes, three treatments decreased superoxide dismutase (SOD) activity and catalase (CAT) activity by 3.41-38.57% and 24.27-30.33% in week 7, respectively. So BFe1 group application immobilized Cd in soil and reduced Cd partitioning in the aboveground tissues. Overall the combination of biochar and α-Fe2O3 NPs can alleviate Cd toxicity in muskmelon and can protect human beings from Cd exposure.

Compound repair effect of carbon dots and Fe2+ on iron deficiency in Cucumis melon L.

Iron-deficiency is one of the most widespread micronutrient deficiency faced by plants, and proper iron supplementation is essential for the growth of crops and for people to obtain iron from food. In order to explore new methods of iron supplementation, we studied the repair effect of CDs on iron-deficient (Cucumis melo L.) muskmelon. Iron-deficient muskmelons were treated with different concentrations of Fe2+, CDs and their complexes. The results showed that CDs significantly increased the iron transport rate and it is noteworthy that 75 mg/L CDs increased the iron transport rate of 0.7 mg/L Fe2+ by 134%. The compound treatment reduced the oxidative stress caused by iron deficiency, such as the CAT activity in the leaves of the compound treatment group was 10%-50% lower than that of the iron supplementation alone. Fluorescent imaging results of melon proved that CDs entered into the muskmelon seedlings. In combination with the above results and the adsorption of CDs, we speculated that the way CDs promoted iron absorption and transport was most likely to combine with Fe2+ and co-transport in melon, which changed the content of reactive oxygen species and other free radicals, thus causing changes of physiological state of melon. This study confirmed that CDs had a positive effect on the iron deficiency of muskmelon, and improved the growth of muskmelon under the condition of iron deficiency, which has a certain reference value for further optimization of iron supplementation solution.

The rs1550117 A>G variant in DNMT3A gene promoter significantly increases non-small cell lung cancer susceptibility in a Han Chinese population.

In this study, we conducted a case-control study to explore the association between rs1550117 A>G variant of DNMT3A gene promoter and non-small cell lung cancer (NSCLC) susceptibility in a Han Chinese population. The genotyping of rs1550117 A>G variant was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and confirmed by sequencing. Allele G of rs1550117 was associated with an increased risk of NSCLC. Moreover, individuals carrying the GG genotypes had a higher risk to develop NSCLC than the AA and GA genotype carriers. Further stratified analysis showed that rs1550117 A>G was significantly related to age (> 60 years), male, smoking and drinking. In vivo detection of DNMT3A mRNA levels in NSCLC tissues and in vitro luciferase assays consistently showed that the allele G significantly decreased DNMT3A transcription. Additional functional analysis revealed that the increased binding affinity of transcription repressor SP1, which was associated with allele G of rs1550117, led to the significant decreased expression of DNMT3A. Collectively, our results propose a suppression role of DNMT3A in NSCLC development and emphasize the dual roles of DNMT3A in tumorigenesis.