[Accumulation and Transport Characteristics of Cd, Pb, Zn, and As in Different Maize Varieties].

The enrichment and translocation characteristics of Cd, Pb, Zn, and As by various parts of maize plants were investigated using field experiments in 22 maize varieties simultaneously under uncontaminated, low, middle, and serious heavy metal Cd, Pb, Zn, and As complex-contaminated farmland soil conditions. The relationship between the uptake of Cd, Pb, Zn, and As by maize plants and the morphological content of heavy metals in the soil was also discussed through principal component analysis and correlation analysis of the concentrations of eight heavy metals, including Cd, Hg, As, Pb, Cr, Cu, Ni, and Zn. The results showed that:① the distribution pattern of Cd and Zn contents in different parts of the maize plant was as follows:upper stalk>lower stalk>root>seed, the distribution pattern of Pb was As follows:root>lower stalk>upper stalk>seed, and the As distribution pattern was:root>upper stalk>lower stalk>seed. The different distribution patterns were closely related to the accumulation characteristics of the crop itself and the environmental activity of Cd, Pb, Zn, and As in the soil of the study area. ② There were significant differences in Cd and Pb accumulation among 22 maize cultivars due to their genetic background (P<0.05), which showed four trends:Cd and Pb compound high-accumulation varieties, single Cd or Pb low-accumulation varieties (low Cd and high Pb, low Pb and high Cd), and Cd and Pb compound low-accumulation varieties. Among them, the content of Cd in the grain of the three varieties exceeded the national food safety standard, and the content of Cd in the stem and leaf of 14 varieties exceeded the national food health standard. The Pb content in stems, leaves, and grains of all cultivars did not exceed the standard, but the Pb content in grains of some cultivars was close to the limit and had the risk of exceeding the standard. The content of As in the stem, leaf, and grain of different maize varieties was much lower than the standard limit value, showing a stable low-accumulation characteristic. The content of Zn in the stem and leaf of different maize varieties increased with the increase in the content of Zn in soil, but the content of Zn in grain remained within the threshold of normal plant growth. ③ Cd, Pb, Zn, and As in maize plants in the study area had a certain homology and were mainly affected by the excessive levels of Cd, Pb, Zn, and As pollutants in the soil. This showed that anthropogenic sources were brought about by mine extraction and tailings stockpiles, whereas Cu elements in maize plants were affected by certain anthropogenic pollution sources, though to a limited extent. Hg, Ni, and Cr in maize plants had a certain homology; this showed the natural source of soil parent material and weathering product accumulation. ④ The contents of Cd, Pb, Zn, and As elements in various parts of the corn plant, as well as the contents of Cr and Ni elements all had a very significant positive correlation (P<0.01). The transport mechanisms of Cd, Pb, Zn, and As elements in the plant may have a common. However, there was a synergistic effect in the migration from the root of the corn to the upper part of the ground, and the same was true for the elements of Cr and Ni. The elements of Hg and Cd, Pb, Zn, and As in the corn stems and leaves and Hg and Cd, Hg, As, Pb, Cr, Ni, and Zn in grains all showed certain antagonistic effects. ⑤ The comparison method simultaneously satisfied the following requirements:the contents of Cd, Pb, and As in stems and leaves did not exceed the national food hygiene standards, and the contents of Cd, Pb, and As in the grains did not exceed the national food safety standards. The cluster analysis of Cd, Pb, and As in grains was a low-accumulation group, and the enrichment and transport coefficients of Cd, Pb, and As in the stems and leaves and grains were low as the optimal conditions. C18 (Xianyu 335) could be selected as the optimal maize variety with low accumulation of Cd, Pb, and As and normal Zn content in grain, which is suitable for promoting and applying in the heavy metal complex-polluted farmland around industrial and mining enterprises in north China.

[Synergistic Repair Effect of Calcite-Based Passivator and Low-Accumulation Maize].

In this study, a field experiment of soil passivation and low accumulation-crops was carried out for typical northern alkaline cadmium and lead compound-polluted farmland soil. Calcite was used as the main passivation material, and a small amount of slaked lime, zeolite powder, and biochar were combined to form a group passivation agent. The effects of passivators on soil physicochemical properties, bioavailability of the heavy metals Cd and Pb, and the yield and plant (stalk and seed) content of heavy metals Cd and Pb in low-accumulation maize were investigated under different grouping conditions of calcite+slaked lime (CL), calcite+zeolite (CZ), calcite+biochar (CB), and calcite+slaked lime+zeolite+biochar (CLZB). The results showed that:① all applications of passivating agent ensured the normal growth of maize and slightly increased the 1000 grain weight and maize yield. ② The effects of different calcite-based passivators on soil physical and chemical properties were different. The CL, CZ, CB, and CLZB treatments increased soil pH by 0.46, 0.25, 0.12, and 0.13 units, respectively, but had no significant correlation with soil fertility index (P>0.05). ③ DTPA leaching and ion exchange state contents of Cd and Pb in soil could be significantly reduced by different calcite-based combinations with passivators, and the reduction rates of Cd and Pb in DTPA leaching were 49.36% and 72.55%, respectively. The reduction rates of ion exchange Cd and Pb contents were 55.39% and 78.52%, respectively. ④ The contents of Cd and Pb in stems, leaves, and grains of low-accumulation maize were further reduced by different passivating agents. The contents of Cd and Pb in the stems and leaves of maize were reduced by 45.93% and 67.00% after CLZB treatment, and the contents of Cd and Pb in grains were decreased by 25.17% and 46.62%, respectively. Moreover, the contents of Cd and Pb in DTPA extraction and ion exchange states were significantly positively correlated with the contents of Cd and Pb in corn stems, leaves, and grains (P<0.01). The results showed that the combined use of combination passivators and low-accumulation crop varieties can obtain better restoration effects in the remediation of cadmium and lead combined-polluted farmland in the middle alkaline soil in northern China.

[Cadmium Accumulation Characteristics of Different Heat Varieties Under Cadmium Stress].

In order to provide technical support for the safe utilization of heavy metal-polluted farmland, we screened wheat varieties with a low accumulation of Cd in grain via a pot experiment. For this purpose, we respectively investigated the enrichment and transport characteristics of Cd in various plant parts of 119 wheat varieties under the conditions of 1.5 mg·kg-1 (low content) and 4.0 mg·kg-1 (high content) Cd-contaminated soil and explored the correlation between the Cd content of different organs of wheat and the relationship between Cd content in soil and the uptake of Cd by wheat. The results showed that:① there were significant differences in the ability to accumulate and transport Cd in roots, stems, leaves, and grains of tested wheat varieties (P<0.05). Under the condition of low Cd content, the Cd enrichment ability of each part of the wheat plant was as follows:leaf>stem ≈root>grain; under high-content stress conditions, the Cd enrichment ability of each part of the wheat plant was:leaf>root>stem>grain; under different content conditions, the Cd transport ability of each part of the wheat plant was:leaf>stem>grain. Cd content in the wheat shoot was positively correlated with total Cd content and ion-exchangeable Cd content in soil (P<0.01) and was closely related to strong transpiration under the pot experiment. ② The correlation coefficient r of BCFCd of wheat roots, stems, leaves, and grain was -0.267 to -0.645, showing a very significant negative correlation (P<0.01), indicating that with the increase in soil Cd content, the migration and accumulation degree of Cd in wheat plant organs showed a downward trend. Moreover, the negative correlation between BCFCd and soil Cd content in stems was significantly higher than that in roots, leaves, and grains, indicating that the enrichment of Cd in wheat plants largely depended on the accumulation and transportation of stems. ③ The correlation coefficient r of Cd content between the root and stem, root and leaf, root and grain, stem and leaf, stem and grain, and leaf and grain in low-and high-content groups was 0.450-0.763, showing a very significant positive correlation (P<0.01), indicating that there was a close transport relationship among the wheat organs, and the degree of translocation from the root to stem and stem to leaf was higher than that from the stem to grain and leaf to grain. ④ Using cluster analysis and enrichment and translocation coefficient sequencing, this study screened 16 and 11 wheat varieties with low Cd accumulation under the soil cadmium content of 1.5 mg·kg-1and 4.0 mg·kg-1, respectively. Among them, Luohan 7 could be used as the optimal wheat variety with low Cd accumulation under the conditions of low-, medium-, and high-Cd content.

Identification of tRNA-derived Fragments and Their Potential Roles in Atherosclerosis.

OBJECTIVE: Atherosclerosis (AS), a chronic inflammatory disease, is the basis of cardiovascular disease (CVD). Although the treatment has been greatly improved, AS still imposes a large burden on human health and the medical system, and we still need to further study its pathogenesis. As a novel biomolecule, transfer RNA-derived fragments (tRFs) play a key role in the progression of various disease. However, whether tRFs contribute to atherosclerosis pathogenesis remains unexplored. METHODS: With deep sequencing technology, the change of tRFs expression profiles in patients with AS compared to healthy control group was identified. The accuracy of the sequencing data was validated using RT qPCR. Subsequently, we predicted the potential target genes of tRFs by online miRNA target prediction algorithms. The potential functions of tRFs were evaluated with Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. RESULTS: There were 13 tRFs differentially expressed between patients with AS and healthy controls, of which 2 were up-regulated and 11 were down-regulated. Validation by RT-qPCR analysis confirmed the sequencing results, and tRF-Gly-GCC-009 was highly up-regulated in the AS group based on the results of sequencing which was confirmed by RT-qPCR analysis. Furthermore, GO enrichment and KEGG pathway analyses indicated that 10 signaling pathways were related to tRF-Gly-GCC-009. These pathways might be physiopathological fundamentals of AS, mainly involving in Apelin signaling, Notch signaling and calcium signaling. CONCLUSION: The results of our study provide important novel insight into the underlying pathogenesis and demonstrate that tRFs might be potential biomarkers and therapeutic targets for AS in the future.

[Adsorption of Cd2+ from wastewater by modified fly ash.] / æ”¹æ€§ç²‰ç ¤ç°å¯¹åºŸæ°´ä¸­é•‰çš„å¸é™„ä½œç”¨.

The modified fly ash (MFA) was prepared through roasting the mixture of fly ash and NaOH/Ca(OH)2 at 250 ℃ for 1.5 h. The physicochemical properties of MFA were analyzed by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), surface area analyze (BET), and Fourier transform infrared spectroscopy (FTIR) techniques. Results from BET analysis showed that the BET of MFA was enlarged by 20.6 times compared with FA. Results from SEM analysis showed that the glass phase was dissolved, with a rough surface and porous structure. Results from FTIR analysis demonstrated that -OH played an important role in Cd2+ adsorption. Results from the static adsorption experiment revealed that the removal efficiency of Cd2+ reached 97.3% when 0.2 g MFA was applied while the concentration of Cd2+ was 100 mg·L-1, the solution pH was 7.0, the adsorption temperature was 25 ℃ and the adsorption time was 90 min. In addition, the coexisting cations (K+, Na+, Mg2+, and Ca2+) might inhibit Cd2+ adsorption. Among all the cations, Ca2+ showed a most significant inhibitory effect on the removal of Cd2+. Langmuir isotherm and the pseudo-second-order kinetic models could well describe the adsorption behavior of Cd2+ on MFA, with the maximum adsorption capacity of 55.77 mg·g-1. Meanwhile, thermodynamic studies showed that Cd2+ adsorption onto MFA was spontaneous and endothermic process. MFA had better adsorption capacity than FA and had certain application pro-spects in wastewater treatment.