关键词：
Africa;Asia;Cd;Cr;Cu;Europe;Fe;Fertilizer and pesticide use;Global pollution;Health risk;Heavy metal regulation;Lake pollution;Mining and manufacturing;Mn;Ni;North America;Pb;Pollution history;Pollution-control measure;River pollution;Rock weathering;Source apportionment;South America;Waste discharge;Zn
摘要：
Heavy metal pollution in surface water is a global environmental problem. This study analyzed the trends, health risks, and sources of eight dissolved heavy metal species in river and lake water across five continents (Africa, Asia, Europe, North America, and South America; Oceania was excluded owing to a lack of data) for the period 1970-2017. We wanted to assess the effects of various implemented countermeasures to pollution and to determine those that could be adopted worldwide. Collectively, the water system showed increasing trends for Cd, Cr, Cu, Ni, Mn, and Fe and decreasing trends for Pb and Zn. The mean dissolved concentrations of most heavy metals were highest in Asia and lowest in Europe. Most heavy metals had low non-carcinogenic risks over this period. The cancer risks associated with Pb were lower than the hazardous level on all five continents over the five decades, whereas the cancer risks related to Cr exceeded the hazardous level in the 1970s, 2000s, and 2010s, and in Africa, Asia, and North America over the entire period. Mining and manufacturing were consistently found to be critical sources of metal pollution from 1970 to 2017. However, the heavy metal sources differed significantly by continent, with waste discharge and rock weathering dominant in Africa; mining and manufacturing, along with rock weathering, are dominant in Asia and South America; fertilizer and pesticide use, along with rock weathering, are dominant in North America; and mining and manufacturing, waste discharge, and rock weathering are dominant in Europe. Global trends in the metal loadings in water and in relevant pollution-control measures suggest that countermeasures in Europe have successfully controlled heavy metal pollution. The successful measures include implementing rigorous standards for metal emissions, limiting the metal concentrations in products, and rigorously treating metal-contaminated waste. Therefore, the measures implemented in Europe should be extended worldwide to treat heavy metal pollution in water.
摘要：
A piezoelectric quartz crystal impedance (PQCI) sensor was used to investigate influences of the insecticide methamidophos on proteinase activity in midguts of the wolf spider, Pardosa pseudoamulata (Araneae: Lycosidae). Results from PQCI indicated that low-concentration dose methamidophos (0.008%) can activate the proteinase but high-concentration dose methamidophos (0.016-0.032%) can inhibit the enzyme activity. The changes in subcellular structure of spider midgut cells were also observed. Electron micrographs of spider midgut epithelial cells showed that the low-dose methamidophos did not visibly impact the structure of these cells. Conversely, high-concentration dose methamidophos led to severe changes in the cell structure, including the karyotheca dissolved, the nucleolus, and the endoplasmic reticulum disappeared. These may contribute to changes in proteinase activity of spider. This work documents a feasible method for rapid and reliable detection of proteinase activity.
摘要：
Metal-free g-C3N4 is always limited by low surface area, rapid charge recombination and limited visible light absorption. In this study, novel porous nitrogen self-doped g-C3N4 nanosheets were prepared by a combination of N self-doping and thermal exfoliation process. Compared to the bulk g-C3N4, N self-doped g-C3N4 nanosheets possessed a high specific surface area of 74.79m(2)g(-1), enhanced visible light absorption, improved photogenerated electron-holes separation, and prolonged lifetime of photogenerated charge carriers. As a consequence, N self-doped g-C3N4 nanosheets exhibited higher photocatalytic activity for tetracycline (TC) degradation than that of bulk g-C3N4, N self-doped g-C3N4 and g-C3N4 nanosheets. It also exhibited remarkable stability and repeatability. The detailed photocatalytic mechanism was proposed. The midgap states created by N doping can significantly enlarge the visible light absorption, reduce the recombination and prolong the lifetime of photogenerated charge carries. The nanosheet construction can provide increased surface area, abundant active sites, short charge diffusion distance, fast separation and promoted redox abilities of photoexcited charge carries.
期刊：
Molecular Genetics and Genomics,2019年294(1):35-45 ISSN：1617-4615
通讯作者：
Chen, Cuixia
作者机构：
[Chen, Cuixia; Yang, Yinqing; Ge, Chunxia; Jia, Shengfeng] Shandong Agr Univ, State Key Lab Crop Biol, Tai An 271018, Shandong, Peoples R China.;[Chen, Cuixia; Yang, Yinqing; Ge, Chunxia; Jia, Shengfeng] Shandong Agr Univ, Coll Agron, Tai An 271018, Shandong, Peoples R China.;[Che, Lu] Shandong Agr Univ, Network Informat Technol Ctr, Tai An 271018, Shandong, Peoples R China.;[Ai, Xin] Hunan Agr Univ, Coll Hort & Landscape, Changsha 410128, Hunan, Peoples R China.;[Yi, Zili] Hunan Agr Univ, Coll Biosci & Biotechnol, Changsha 410128, Hunan, Peoples R China.
通讯机构：
[Chen, Cuixia] S;Shandong Agr Univ, State Key Lab Crop Biol, Tai An 271018, Shandong, Peoples R China.;Shandong Agr Univ, Coll Agron, Tai An 271018, Shandong, Peoples R China.
摘要：
Miscanthus is recognized as a promising lignocellulosic crop for the production of bioethanol and bioproducts worldwide. To facilitate the identification of agronomical important traits and establish genetics knowledge, two genetic maps were developed from a controlled interspecific cross between M. floridulus and M. sacchariflorus. A total of 650 SSR markers were mapped in M. floridulus, spanning 19 linkage groups and 2053.31 cM with an average interval of 3.25 cM. The map of M. sacchariflorus comprised 495 SSR markers in 19 linkage groups covering 1684.86 cM with an average interval of 3.54 cM. The estimation on genome length indicated that the genome coverage of parental genetic maps were 93.87% and 89.91%, respectively. Eighty-eight bi-parental common markers were allowed to connect the two maps, and six pairs of syntenic linkage groups were recognized. Furthermore, quantitative trait loci (QTL) mapping of three agronomic traits, namely, plant height (PH), heading time (HT), and flowering time (FT), demonstrated that a total of 66 QTLs were identified in four consecutive years using interval mapping and multiple-QTL model. The LOD value of these QTLs ranged from 2.51 to 10.60, and the phenotypic variation explained varied from 9.50 to 37.10%. QTL cluster in syntenic groups MF19/MS7 contained six stable QTLs associated with PH, HT, and FT. In conclusion, we report for the first time the genetic mapping of biomass traits in M. floridulus and M. sacchariflorus. These results will be a valuable genetic resource, facilitating the discovery of essential genes and breeding of Miscanthus.
摘要：
There have been no studies demonstrating the correlation between soil nutrient heterogeneity and cadmium (Cd) absorption of Bermudagrass. In this study, a pot experiment was carried out to study the correlation between them. The purpose is to find soil nutrient factors which are conducive to improving the Cd absorption and translocation. The eighth group had the largest total number of surviving plants, the highest Fv/Fo value (3.24) and the best growth characteristics. The fifth group had the lowest total number of surviving plants, Fv/Fo (2.47) and the worst growth. The Cd content of the fifth group (36.11 mg kg(-1)) was close to the eighth group (35.72 mg kg-1), but the two groups had significant differences in plant height, stem node length and stem node number (P < 0.05). The eighth group showed the highest contents of nitrate nitrogen (NO3--N), available potassium and urease activity. The fifth group showed the lowest NO3--N content, but the highest ammonium nitrogen (NH4+-N) and available phosphorus content. There was significant difference of the Cd bioconcentration factors (BCF) and trans location factor (TCF) between the fifth and the eighth group although they had the similar total soil Cd content (P < 0.05). The fifth group had the highest BCF and TCF. RDA analysis indicated the BCF and TCF were positively correlated with soil NH4+-N and available phosphorus and negatively correlated with soil NO3--N. The results demonstrated that soil NHI-N and available phosphorus were important soil ecological factors to enhance Cd absorption and translocation of bermudagrass. (C) 2019 Elsevier Ltd. All rights reserved.
关键词：
Carbon;Karst ecosystem;Nitrogen;Phosphorus;Soil layer;Vegetation type
摘要：
The cyclic process of carbon (C), nitrogen (N), and phosphorus (P) elements is an important factor affecting the function of the forest ecosystem. However, the relation between soil and root stoichiometric ratios, especially in karst areas with extremely fragile geology and intensive human disturbance has rarely been investigated. In the current study the concentrations of C, N, and P and their stoichiometric characteristics were investigated using sequential soil coring under different stages of vegetation restoration (primary forest, secondary forest, shrubland and grassland) and soil layer (0-10cm, 10-20cm, 20-30cm) in fine root and soil samples. The results showed that total C concentration had no significant change in all four vegetation types and three soils layer in the fine root, whereas total N and P concentration reached the maximum value in secondary forest and the minimum in grassland. In addition, soil organic C (SOC) and total N increased continuously with natural succession and decreased with soil depth. Secondary forest showed the largest total P concentration in soil, with the smallest corresponding to grassland. Furthermore, both vegetation type and soil layer significantly affected soil C, N, and P stoichiometric ratios. There was a positive correlation among C, N and P in the fine roots, as well as in the soil. While fine root C:N and C:P ratios were negatively related to soil C:N and C:P, fine root N:P was significantly related to soil N:P. This study can provide a scientific basis for the restoration of fragile ecosystem vegetation and for comprehensive treatment of rocky desertification in karst.
摘要：
The lack of sophisticated in vitro models limits our current understanding of gastrointestinal functions in farm animals. Conventional 2D cell lines or primary cells fail to recapitulate the physiology of in vivo intestinal epithelium. In contrast stem cell-derived, nontransformed 3D enteroids partially recreate the villus-crypt anatomy of the native intestine and comprise most if not all intestinal cell types including enterocytes, enteroendocrine cells, goblet cells, Paneth cells, and stem cells. This review summarizes the techniques used for generating and culturing enteroids of various farm animal species, focuses on important factors influencing the longevity of enteroids, and provides an overview of their current applications in modeling veterinary pathogens and in developing chemicals and bioactives for treating animal disease and improving production performance. It also mentions current limitations of enteroid models and potential solutions and highlights the opportunities for using these enteroids as a platform in studies regarding veterinary sciences and animal nutrition.
摘要：
Bioaccumulation of heavy metals in aquatic plants is significantly affected by hydrological regime and therefore the accumulation and translocation of cadmium in five organs-panicle, leaf, stem, root, and bud-of an emergent plant (Miscanthus sacchariflorus) were compared between the submerged environment and non-submerged environment. In the submerged condition, the cadmium concentration was higher in the panicle and leaf than in the stem, root, and bud. Cadmium concentration in the root exhibited a positive regression with cadmium concentration in the sediment. However, cadmium concentration in the panicle, leaf, stem, and bud exhibited no significant regression with cadmium concentration in the sediment. In the non-submerged environment, the cadmium concentration was higher in the below-ground organs than in the aboveground organs. The mean bioaccumulation coefficient in the 24 investigated plots in the submerged environment was higher than that in the 20 and 40 mg kg(-1) cadmium treatments in the non-submerged environment. The mean translocation factor in the submerged environment was nine times higher than that in non-submerged environment. These results indicate that submergence enhanced cadmium bioaccumulation in the aboveground organs and that this plant can be used to remove heavy metals from polluted rivers and lakes.
摘要：
As a new class of promising fluorescent carbon nanomaterials, carbon dots (CDs) have been well developed in recent years for their excellent fluorescent properties, simple synthetic approaches, good biocompatibility and various detection applications, which can be expected to replace the tradition semi-quantum dots. This review aims presents the current progress in the development of CDs with an emphasis on fluorescent properties, synthetic approaches and applications in food safety. First, the fluorescent properties of CDs are briefly introduced. To seek more reasonable synthetic approaches, the characteristics of the diverse methods of CD synthesis are summarized. And then, applications of CDs as fluorescent probes in food safety are discussed, with emphasis on the determination of metal ions/anions, pesticides, veterinary drugs, bacteria, functional components and banned additives. Finally, the challenges, such as how to explain the diversity of fluorescent properties, and how to form a uniform synthesis procedure to improve the quantum yield (QY), for CDs are presented. Although CDs have found many applications in food safety, it is still a challenge to detect a specific target in complex samples. Therefore, combination with other biochemistry technology to exploit novel ligands against the specific target with high binding affinity and selectivity is vitally important for developing sensitive and specific sensing probes in the future.
摘要：
In this work, a label-free fluorescence biosensor was proposed for simple detection of the Kras wild type by using the three way DNA junction-driven catalyzed hairpin assembly strategy. In this system, a three-way DNA junction probe (JP) and two hairpin probes (H1 and H2) were designed. In the presence of the Kras wild type, an autocatalytic DNA machine can be activated. This leads to the generation of numerous free G-rich sequences, which can associate with a fluorescent dye N-methylmesoporphyrin IX (NMM) to yield an amplified fluorescence signal for the target detection. This sensing platform showed a high sensitivity towards the Kras wild type with a detection limit as low as 2.7 fM without any labelling, immobilization, or washing steps. The designed sensing system also exhibits an excellent selectivity for the Kras wild type compared with other interference DNA sequences. Furthermore, the presented biosensor is robust and has been successfully applied for the detection of the Kras wild type in a real biological sample with satisfactory results, suggesting that this method is promising for simple and early clinical diagnosis of genetic diseases. Thanks to its simplicity, cost-effectiveness, and ultrasensitivity, our proposed sensing strategy provides a universal platform for the detection of other genetic diseases by substituting the target-recognition element.
摘要：
Soil bacteria play key roles in determining soil health and plant growth. In this study, four sweet potato fields that had been consecutively monocultured for 1, 2, 3, and 4 years were used to investigate the effect of monoculture on soil physicochemical properties and soil bacterial communities. The results revealed that continuous cropping led to a significant decline in soil pH, soil organic carbon, and soil bacterial abundance. Miseq pyrosequencing analysis of 16S rRNA genes revealed that Proteobacteria and Bacteroidetes were the main phyla in the sweet potato monoculture soils, comprising up to 66.24% of the total sequences. The relative abundances of beneficial bacteria, including Actinobacteria, Gemmatimonadetes, Firmicutes, Xanthomonadaceae, Rhodospirillaceae, and Syntrophobacteraceae, as well as their subgroups at the genus and operational taxonomic unit (OTU) levels, decreased considerably as the number of continuous cropping years increased. In contrast, the number of potentially pathogenic bacteria, such as Acidobacteria, Sphingomonadaceae, and Pedobacter accumulated with increasing years. The results also showed the alterations to the bacterial community in the sweet potato monoculture soils were mainly driven by soil pH and soil organic matter. Overall, the decline in soil quality after successive sweet potato monoculture can be attributed to the imbalance in soil properties and soil microbes, including the decrease in soil pH and soil organic carbon, and the enrichment of pathogenic bacteria at the expense of plant-beneficial bacteria.
