[Comparison of Regional Transportation and Transformation Models of Atmospheric Polycyclic Aromatic Hydrocarbons and Research on Key Influencing Factors: Take the Beijing-Tianjin-Hebei Region as Example].

In this study, taking the Beijing-Tianjin-Hebei region as an example, CMAQ and BETR models were constructed to carry out numerical simulation for the pyrene (Pyr) and benzo[a] pyrene (BaP) in 2014. The model results were compared and evaluated for the atmospheric transportation and transformation of PAHs. Additionally, the XGBoost model was used to identify the key atmospheric physicochemical processes and parameters that affect the environmental behavior of PAHs in the CMAQ. The results showed that the ratio of the simulated value of BETR and annual average value of CMAQ to the measured annual average value was between 1/2 and 2, and the seasonal trend of the simulated concentrations of Pyr and BaP from the CMAQ model were basically consistent with the measured values, which verified the reliability of the two types of models. At the same time, the simulated concentration of the CMAQ model averaged from 9 km grid to 27 km grid and was comparable to the BETR concentration. The results showed that the average concentrations of Pyr and BaP in the BETR model were approximately 1.59 and 1.38 times those of the CMAQ simulation concentrations, respectively, indicating that the two models had good comparability in terms of average annual concentration level and spatial distribution. The SHAP-based variable importance on the XGBoost model showed that boundary layer height was the most significant meteorological factor affecting the transportation and transformation of Pyr and BaP, accounting for 22%-35% of all factors, and sometimes even exceeded the emissions for certain cities and pollutants. The boundary layer height was significantly negatively correlated with the concentration of PAHs. Wind speed was a secondary factor affecting the concentration of PAHs and was negatively correlated with the PAHs, whereas the influence of wind direction on the concentration of PAHs varied.

4,4'­Bond secalonic acid D targets SP cells and inhibits metastasis in hepatocellular carcinoma.

The existence of cancer stem cells (CSCs) is considered to be the main reason for chemoresistance, metastasis and the ultimate failure of treatment in hepatocellular carcinoma (HCC). However, there are a few chemical agents that may inhibit CSCs. The present study identified that 4,4'­bond secalonic acid D (4,4'­SAD), a compound isolated from the marine­derived fungus Penicillium oxalicum, inhibited the growth of side population (SP) cells isolated from human liver cancer cell lines PLC/PRF/5 and HuH­7 by attenuating the expression of ATP­binding cassette superfamily G member 2. Furthermore, the results of wound healing, Transwell, western blotting and reverse transcription­quantitative PCR assays demonstrated that 4,4'­SAD suppressed the invasion and migration of SP cells by downregulating matrix metallopeptidase 9 (MMP­9) and upregulating the antagonist tissue inhibitor of metalloproteinases 1 in vitro. Moreover, in vivo study results found that 4,4'­SAD had anti­lung metastasis efficacy via the decrease of MMP­9 expression in the H22 HCC model of Kunming mice. Therefore, the present study identified the potential of 4,4'­SAD as a promising candidate for the treatment of advanced liver cancer.

[The NMD escape mechanism and its application in disease therapy].

Nonsense-mediated mRNA decay (NMD) refers to the degradation of mRNA due to the presence of premature stop codon (PTC) on mRNA under pathological or physiological conditions. NMD is widely considered an mRNA-specific quality control process. Recently it was discovered that some PTCs do not trigger NMD in a variety of diseases - a process known as NMD escape; however, its exact mechanism remains unclear. At present, there are two widely accepted mechanistic hypotheses during NMD escape. The first is PTC read-through, in which protein translation undergoes PTC until the normal stop codon is encountered, producing a full-length protein. The second is translation reinitiation, in which protein translation recommences at the potential start codon downstream of PTC and terminates at the stop codon, producing an N-terminal truncated protein. Currently, an increasing number of drugs or small molecules that use PTC read-through have been successfully applied to treat nonsense variation-associated diseases. In this review, we summarize the NMD mechanism and discuss the application and progress in our understanding of NMD escape in disease therapy. This review should provide a useful framework to advance current understanding of the research and application of NMD escape.

[Effect of Bt rice straw returning in soil on the growth and reproduction of Eisenia fetida.] / Bt水稻秸秆还田对赤子爱胜蚓生长发育和生殖的影响.

Bacillus thuringiensis (Bt) protein can enter the soil through Bt crops straw returning to field, which may affect the growth and reproduction of soil animals, such as earthworms. Here, Bt rice (b2B138) and conventional rice (Anfeng A) straw were returned in soil to evaluate the impact of Bt rice on Eisenia fetida. Two varieties of rice straw were added into soil to breed E. fetida at the rates of 2.5%, 5%, 7.5% and 10%. The survival rate, relative growth rate, reproduction of earthworm, the Cry1Ab content in soil-straw mixture and earthworm were detected after 7, 15, 30, 45, 60, 75, 90 d. The results showed that Bt rice straw returning at higher concentrations (7.5% and 10%) inhibited the survival rate of E. fetida. Bt rice straw returning had no adverse effect on relative growth rate (RGR) of E. fetida. Bt rice straw treatment improved the reproduction of earthworms under 5%, 7.5% and 10% straw returning in soil. Enzyme-linked immunosorbent assay (ELISA) results indicated that immunoreactive Cry1Ab was detectable in soil-straw mixture and E. fetida from Bt rice treatments, and a strong decline was observed in soil-straw mixture with the increase of treated time. Therefore, Cry1Ab released from Bt rice straw returning at 2.5% and 5% concentration had no adverse effects on the growth and reproduction of E. fetida.

[Environmental effects of applying heavy metal-containing municipal sewage sludge on wheat-rice rotation system on different types of soil].

A pot experiment with the yellow soil and limestone soil from Guizhou province, and paddy soil from Zhejiang Province was conducted to study the impacts of applying municipal sewage sludge containing different concentrations of heavy metals on the wheat and rice growth and their Zn and Cd absorption. The risks of the crop heavy metals pollution caused by the application of the same sludge differed with tested soils. On the yellow soil and paddy soil, applying the sludge containing high concentration heavy metals induced higher pollution risks to the crops. Applying the sludge 1.6% in dry mass and containing 1789 mg x kg(-1) of Zn and 8.47 mg x kg(-1) of Cd to yellow soil made the Zn and Cd concentrations in wheat grains reached 109 and 0.08 mg x kg(-1), and after the second time application of the same dosage of this sludge after rice planting, the Zn and Cd concentrations in brown rice reached 52.0 and 0.54 mg x kg(-1), respectively. However, applying the sludge to calcareous soil had no pollution risk to the edible parts of wheat and rice. Soil NH4OAc-extractable Zn was the main factor affecting the Zn concentration in wheat grain and brown rice, but soil NH4OAc-extractable Cd had less effect on the Cd concentration in wheat grain and brown nce. Applying the sludge containing high concentration Zn and Cd to the three soils made the concentrations of total Zn and Cd in the soils increased significantly, and after the first time and the second time of the application, the total Zn concentration in the soils all exceeded the 2nd level of the national soil environmental quality standards.

[Effects of intercropping Sedum plumbizincicola in wheat growth season under wheat-rice rotation on the crops growth and their heavy metals uptake from different soil types].

A pot experiment with heavy metals- contaminated black soil from Heilongjiang Province, alluvial soil from Henan Province, and paddy soil from Zhejiang Province was conducted to study the effects of intercropping Sedum plumbizincicola in wheat growth season under wheat (Triticum aestivum) - rice (Oryza sativa) rotation on the growth of the crops and their heavy metals uptake, aimed to explore the feasibility of simultaneous grain production and heavy metals-contaminated soil phytoremediation in main food crop production areas of this country. Comparing with monoculture T. aestivum, intercropping S. plumbizincicola increased the soil NaNO3 -extractable Zn and Cd significantly, with the increment of extractable Zn in test paddy soil, alluvial soil, and black soil being 55%, 32% and 110%, and that of extractable Cd in test paddy soil and black soil being 38% and 110%, respectively. The heavy metals concentration in T. aestivum shoots under intercropping S. plumbizincicola was 0.1-0.9 times higher than that under monoculture T. aestivum, but the intercropping had little effects on the rice growth and its heavy metals uptake. Though the Cd concentration in rice grain after S. plumbizincicola planting was still higher than 0.2 mg kg(-1) (the limit of Cd in food standard), it presented a decreasing trend, as compared with that after monoculture T. aestivum. Therefore, intercropping S. plumbizincicola in wheat growth season under wheat-rice rota- tion could benefit the phytoremediation of heavy metals-contaminated soil, and decrease the food-chain risk of rotated rice.