大气颗粒物污染对土地覆盖变化的响应

土地利用-覆盖变化(LUCC)直接或间接影响颗粒物污染。了解颗粒物污染对LUCC的响应,对维护和改善生态环境具有重要的意义。基于卫星遥感技术,从广域的空间尺度分析颗粒物污染对LUCC的响应。使用MODIS数据分别提取与颗粒物污染相关性较高的城市用地、林地等土地利用类型,确定土地利用类型的变化趋势,利用长时间序列MODIS气溶胶光学厚度(AOD,Aerosol optical depth)产品分析颗粒物污染与土地利用类型的变化的相关性。以山东省青岛市、淄博市、济南市3个典型城市为例,研究了AOD随土地利用类型的变化趋势。同时,考虑并分析了颗粒物污染对土地利用变化响应的敏感性,以及城市区域变化对环境的影响。研究结果表明,不同的城市类型,由于决定环境变化主导因素的差异,颗粒物污染对LUCC的响应具有明显的差异。青岛市地区,由于受海洋影响显著,大气颗粒物污染与LUCC的相关性较低,如中度污染天气与林地的相关系数为-0.451;而淄博市和济南市的相关系数分别为-0.473、-0.507。     

不同预处理对大麦花药3种内源激素含量和过氧化物酶活性的影响

研究了大麦（Ｈｏｒｄｅｕｍ ｖｕｌｇａｒｅ Ｌ．）花药－花粉培养中不同预处理对花药内源激素（ＡＢＡ,ＩＡＡ,ＩＰＡ）含量和过氧化物酶活性的影响。结果表明：１． 经甘露醇预处理不同天数,同一种基因型的３种内源激素的变化和不同基因型的同一种内源激素的变化规律十分相似,均是在预处理初期含量急剧增加,最高值在０．５或１ ｄ 处。以后开始逐渐下降;最后,保持在一定的水平上。２． 在甘露醇预处理过程中,两种基因型花药过氧化物酶活性的变化规律也十分相似。在预处理前期（从开始到第３天）活性呈直线上升,第３天达到最大值。从第３天到第５天活性减弱。最后,活性又开始增强。３． 在低温预处理过程的初期（２～５ ｄ） 两种基因型花药过氧化物酶活性都出现第一个小峰。在第１４天（“Ｈａｒｒｉｎｇｔｏｎ”）或第２１天（“Ｉｇｒｉ”）又出现第二个峰值,但后者较高。在预处理的后期（从第２８天到第３５天）两种基因型花药过氧化物酶的活性又呈现上升的趋势。同甘露醇预处理后期变化一致     

Phosphorylation on tyrosine-15 of p34(Cdc2) by ErbB2 inhibits p34(Cdc2) activation and is involved in resistance to taxol-induced apoptosis

ErbB2 overexpression confers resistance to taxol-induced apoptosis by inhibiting p34(Cdc2) activation. One mechanism is via ErbB2-mediated upregulation of p21(Cip1), which inhibits Cdc2. Here, we report that the inhibitory phosphorylation on Cdc2 tyrosine (Y)15 (Cdc2-Y15-p) is elevated in ErbB2-overexpressing breast cancer cells and primary tumors. ErbB2 binds to and colocalizes with cyclin B-Cdc2 complexes and phosphorylates Cdc2-Y15. The ErbB2 kinase domain is sufficient to directly phosphorylate Cdc2-Y15. Increased Cdc2-Y15-p in ErbB2-overexpressing cells corresponds with delayed M phase entry. Expressing a nonphosphorylatable mutant of Cdc2 renders cells more sensitive to taxol-induced apoptosis. Thus, ErbB2 membrane RTK can confer resistance to taxol-induced apoptosis by directly phosphorylating Cdc2.     

Urban development and sustainability challenges chronicled by a century of construction material flows and stocks in Tiexi,China

Construction materials are considerable forces of global environmental impacts, but their dynamics vis‐à‐vis urban development are poorly documented, in part because their long lifespans require elusive and sometimes nonexistent decade‐long high‐resolution data. This study analyzes the construction material flow and stock trends that shaped and were shaped by the development, decline, and renewal of the Tiexi district of Shenyang, a microcosm of China's urban transformations since the early 20th century. Chronicling building‐by‐building the material flows and stock accumulations involved in the buildup of this area, we shed light on the physical resource context of its socioeconomic history. We find that 42 million tonnes of construction materials were needed to develop the Tiexi district from 1910 to 2018, and 18 million tonnes of material outflows were generated by end‐of‐life building demolition. However, over 55% of inflows and 93% of outflows occurred since 2002 during a complete redevelopment of the district. Only small portions of end‐of‐life materials could have been reused or recycled because of temporal and typological mismatches of supply and demand and technical limitations. Our analysis reveals a dramatic decrease in median building lifetimes to as low as 6 years in the early 21st century. These findings contribute to the discussion of long‐term environmental efficiency and sustainability of societal development through construction and reflect on the challenges of urban renewal processes not only in China but also in other developing and developed countries that lost (or may lose) their traditional economic base and restructure their urban forms. This article met the requirements for a Silver/Silver JIE data openness badge described at http://jie.click/badges .     

嗜盐菌群对酸性金黄G的脱色特性和机理

【目的】为了获得能够在高盐环境下脱色偶氮染料的嗜盐菌群及其降解机理。【方法】采用富集驯化的方法获得一个嗜盐菌群,采用Illumina HiSeq2500测序平台对其群落结构进行测定;采用分光光度法测定了其降解特性;采用GC-MS和红外图谱分析了其降解机理;采用微核实验的方法比较了偶氮染料降解前后的毒性。【结果】该菌群在10%的盐度下,使100mg/L的酸性金黄G在8h内脱色。菌群主要由Zobellella、Rheinheimera、Exiguobacterium和Marinobacterium组成。最适宜的脱色条件是:pH=6,酵母粉为碳源,蛋白胨或硝酸钾作为氮源,盐度为1%–10%。酸性金黄G降解产物的毒性比降解前降低。酸性金黄G主要的降解产物是对氨基二苯胺和二苯胺。此外,该菌群还能使酸性大红GR和直接湖蓝5B等多种偶氮染料脱色,具有较好的脱色广谱性。【结论】获得了快速降解偶氮染料的嗜盐菌群及降解机理,为该嗜盐菌群应用于高盐印染废水的处理提供菌种资源和理论支持。     

Combinatorial signals of activin/nodal and bone morphogenic protein regulate the early lineage segregation of human embryonic stem cells

Cell fate commitment of pre-implantation blastocysts, to either the inner cell mass or trophoblast, is the first step in cell lineage segregation of the developing human embryo. However, the intercellular signals that control fate determination of these cells remain obscure. Human embryonic stem cells (hESCs) provide a unique model for studying human early embryonic development. We have previously shown that Activin/Nodal signaling contributes to maintaining pluripotency of hESCs, which are derivatives of the inner cell mass. Here we further demonstrate that the inhibition of Activin/Nodal signaling results in the loss of hESC pluripotency and trophoblast differentiation, similar to BMP4-induced trophoblast differentiation from hESCs. We also show that the trophoblast induction effect of BMP4 correlates with and depends on the inhibition of Activin/Nodal signaling. However, the activation of BMP signaling is still required for trophoblast differentiation when Activin/Nodal signaling is inhibited. These data reveal that the early lineage segregation of hESCs is determined by the combinatorial signals of Activin/Nodal and BMP.     

MiR‐616‐3p modulates cell proliferation and migration through targeting tissue factor pathway inhibitor 2 in preeclampsia

Objectives

Despite improvements in diagnosis and treatment, preeclampsia (PE) continues to pose a significant risk of maternal and foetal morbidity and mortality if not addressed promptly. An increasing number of studies have suggested that tissue factor pathway inhibitor 2 (TFPI2) acts as a suppressor gene, possibly inhibiting multiple serine proteases affecting cell proliferation and migration. It plays an essential role in the occurrence and development of PE, but the pathogenesis remains unclear.

Materials and methods

In our research, we performed western blotting, immunohistochemistry and qPCR assays to investigate TFPI2 and miR‐616‐3p expression in preeclamptic placental tissues. Cell assays were performed in HTR‐8/SVneo and JEG3 cell lines. Cell proliferation and migration events were investigated by MTT, EdU and transwell assays. In conjunction with bioinformatics analysis, luciferase reporter assays were performed to elucidate the mechanism by which miR‐616‐3p binds to TFPI2 mRNA.

Results

We established that TFPI2 protein levels were significantly upregulated in PE placental tissues. In addition, we found that miR‐616‐3p binds specifically to the 3′‐UTR region of TFPI2 mRNA. Furthermore, miR‐616‐3p knockdown or TFPI2 overexpression substantially impaired cell growth and migration, whereas miR‐616‐3p upregulation or TFPI2 knockdown stimulated cell proliferation and migration. This miR‐616‐3p / TFPI2 axis was also found to affect the epithelial‐mesenchymal transition process in PE.

Conclusions

Our results demonstrated that TFPI2 plays a vital role in the progression of PE and might provide a prospective therapeutic strategy to mitigate the severity of the disorder.

     

定向进化提高来源于Arthrobacter ramosus的MTHase的热稳定性

麦芽寡糖基海藻糖水解酶(mahosyhrehalose hydrolase,MTHase)是以淀粉或麦芽糊精为底物制备海藻糖的关键酶之一.来源于Arthrobacter ramosus的MTHase,表达量好,比活高,但热稳定性差,限制了其工业化应用.采用定向进化技术,筛选得到L137M和A216T两个突变体,在60℃...     

改良三倍体鲫鱼的生物学特性研究

利用鱼类远缘杂交和雌核发育相结合的方法培育出改良四倍体鲫鲤和改良二倍体红鲫,两者交配制备出一种改良三倍体鲫鱼（湘云鲫2号）.对改良三倍体鲫鱼的染色体数目和组型、性腺和垂体结构、外形特征、生长速度等方面进行了系统的研究.结果表明,改良三倍体鲫鱼的染色体数目为3n=150,核型公式为33m＋51sm＋33st＋33t;其精巢和卵巢在繁殖季节不能产生成熟配子,垂体超微结构显示,GTH细胞内的分泌颗粒和分泌小球在繁殖季节没有大量排出,该特征从内分泌的角度证明了它们的不育性;改良三倍体鲫鱼具有体背高、尾柄短和头部小的优良外形特征.与三倍体湘云鲫相比,改良三倍体鲫鱼不但保留了三倍体鱼生长速度快、不育等特点,而且在体形方面表现出明显的改良特征,是一种新型改良三倍体鲫鱼.     

The effects of Bacillus thuringiensis Cry6A on the survival, growth, reproduction, locomotion, and behavioral response of Caenorhabditis elegans

Several families of crystal proteins from Bacillus thuringiensis exhibit nematicidal activity. Cry5B protein, a pore-forming toxin, has been intensively studied yielding many insights into the mode of action of crystal protein at molecular level and pathogenesis of pore-forming toxins. However, little attention was paid to Cry6A, another representative nematicidal crystal protein. Cry6A shares very low homology with Cry5B at amino acid sequence and probably acts in a distinct pathway from Cry5B and even the other main commercial crystal proteins. In the current study, we comprehensively investigated the nematicidal properties of Cry6Aa2 against the free-living soil nematode Caenorhabditis elegans and examined the physical response of C. elegans to Cry6Aa2 attack. Our results indicate that Cry6Aa2 exhibits high lethal activity to C. elegans and could cause detrimental effects on C. elegans, including obviously suppressed growth, decreased brood size, and even abnormal motility. Meanwhile, our study additionally shows that C. elegans could defend against the Cry6Aa2 toxin harmful threat through behavioral defense responses, such as reduced oral uptake and physical avoidance. In general, this study suggests that Cry6Aa2 possesses diverse nematicidal properties, which strongly indicates that Cry6Aa2 is a promising potential candidate of nematicidal agent. Moreover, this study highlights the importance of behavioral responses in defense of C. elegans for survival and demonstrates the key role of crystal protein in the interaction of B. thuringiensis–C. elegans. These findings could shed light on understanding the interaction of C. elegans with B. thuringiensis and provide a perfect model to study the role of pathogenic factor in the interaction of pathogen–host.