The Puccinia striiformis effector Hasp98 facilitates pathogenicity by blocking the kinase activity of wheat TaMAPK4

The obligate biotrophic fungus Puccinia striiformis f. sp. tritici (Pst) employs virulence effectors to disturb host immunity and causes devastating stripe rust disease. However, our understanding of how Pst effectors regulate host defense responses remains limited. In this study, we determined that the Pst effector Hasp98, which is highly expressed in Pst haustoria, inhibits plant immune responses triggered by flg22 or nonpathogenic bacteria. Overexpression of Hasp98 in wheat (Triticum aestivum) suppressed avirulent Pst-triggered immunity, leading to decreased H₂O₂ accumulation and promoting P. striiformis infection, whereas stable silencing of Hasp98 impaired P. striiformis pathogenicity. Hasp98 interacts with the wheat mitogen-activated protein kinase TaMAPK4, a positive regulator of plant resistance to stripe rust. The conserved TEY motif of TaMAPK4 is important for its kinase activity, which is required for the resistance function. We demonstrate that Hasp98 inhibits the kinase activity of TaMAPK4 and that the stable silencing of TaMAPK4 compromises wheat resistance against P. striiformis. These results suggest that Hasp98 acts as a virulence effector to interfere with the MAPK signaling pathway in wheat, thereby promoting P. striiformis infection.     

The Ras GTPase-activating-like protein IQGAP1 is downregulated in human diabetic nephropathy and associated with ERK1/2 pathway activation

Podocyte injury may contribute to the pathogenesis of diabetic nephropathy (DN), but the underlying mechanism of hyperglycemia induced podocyte damage is not fully understood. The Ras GTPase-activating-like protein IQGAP1 is associated to the slit diaphragm proteins and the actin cytoskeleton in podocyte. Here, we studied IQGAP1 expression alterations in human DN biopsies and extracellular signal-regulated kinase (ERK)-dependent pathways of IQGAP1 expression in podocyte under high glucose (HG) media. In vivo, analysis of renal biopsies from patients with DN revealed a significant reduction in IQGAP1 expression compared to controls. In vitro, IQGAP1 mRNA and protein expression were observed to decline under HG media at 48 h. But phosphorylation of ERK1/2 was activated under HG media at 24 h and 48 h. However, HG-induced downregulation of IQGAP1 protein was attenuated by specific ERK1/2 activation inhibitor PD98059. Taken together, these results highlight the importance of IQGAP1 in DN, and suggest that IQGAP1 expression in podocyte under HG media is modulated by the ERK1/2 pathway, which may lead to the future development of therapies targeting IQGAP1 dysfunction in podocytes in DN.     

BMP2/7 heterodimer enhances osteogenic differentiation of rat BMSCs via ERK signaling compared with respective homodimers

Bone morphogenetic protein (BMP)2/7 heterodimer shows greater efficacy in enhancing bone regeneration. However, the precise mechanism and the role of mitogen-activated protein kinase (MAPK) signaling network in BMP2/7-driven osteogenesis remain ambiguous. In this study, we evaluated the effects of BMP2/7 heterodimers on osteoblastic differentiation in rat bone marrow mesenchymal stem cells (BMSCs), with the aim to elaborate how MAPKs might be involved in this cellular process by treatment of rat BMSCs with BMP2/-7 with a special signal-pathway inhibitor. We found that BMP2/7 heterodimer induced a much stronger osteogenic response in rat BMSCs compared with either homodimer. Most interestingly, extracellular signal-regulated kinase (ERK) demonstrated a highly sustained phosphorylation and activation in the BMP2/7 heterodimer treatment groups, and inhibition of ERK cascades using U0126 special inhibitor that significantly reduced the activity of ALP and calcium mineralization to a substantial degree in rat BMSCs treated with BMP2/7 heterodimers. Collectively, we demonstrate that BMP2/7 heterodimer shows a potent ability to stimulate osteogenesis in rat BMSCs. The activated ERK signaling pathway involved in this process may contribute partially to an increased osteogenic potency of heterodimeric BMP2/7 growth factors.     

街区尺度屋顶绿化热效应及其与城市形态结构之间的关系

研究探讨大面积屋顶绿化如何改善城市冠层内部三维空间的热环境,改善效果与城市形态结构之间存在的关系。基于三维小气候模型ENVI-met 4.2,开展街区尺度屋顶绿化热效应研究。在南京市选择具有不同形态结构特征的8个典型样区,每个样区设置2种朝向(街道与主导风向平行或相交)、3种屋顶绿化情景(传统光屋顶、简易型绿化、复合型绿化),共对48种情景进行了微气候模拟与分析。结果表明,街区尺度屋顶绿化产生的"冷岛"可从屋面扩散到地面空间,缓解城市冠层热岛效应。白天14:00时,8个样区屋顶1.5 m高处的降温强度最高可达0.64℃,样区平均降温强度最大值为0.44℃;地面1.5 m高处的降温最大值为0.55℃,样区平均降温强度最大值为0.25℃。建筑高度、高宽比、容积率与屋面、地面降温强度之间均存在显著负相关关系;建筑密度与屋面降温强度显著正相关,但与地面降温强度之间无显著相关性。总的来说,紧凑低层建筑区和开敞低层建筑区实施屋顶绿化后产生的降温效应明显高于紧凑和开敞高层建筑区;建筑高度和密度相同时,街道走向与主导风向呈45°夹角比与主导风向平行具有更高的降温强度。研究结果能够促进对亚热带城市地区建筑-植被-大气相互关系的深入认识,并为屋顶绿化实践提供指导。     

晋西黄土区土地利用对降雨入渗产流模式和优先流分布的影响试验研究

黄土高原退耕还林(草)工程显著改变了河川径流过程,但其作用机制尚不明晰。选取晋西黄土区4种典型下垫面(20年和30年刺槐人工林地、草地、休耕地)分别开展连续3场模拟降雨试验,观测坡面入渗产流过程,并结合染色示踪和图像处理软件技术,分析土地利用类型对坡面降雨入渗产流模式和优先流分布的影响。结果表明：(1)累积入渗量和优先流发育程度均表现为刺槐林地>草地>休耕地,刺槐林地优先流对总入渗的贡献是草地和休耕地的2.5—4.5倍,但优先流贡献均不超过10%,仍以基质流入渗为主。(2)4种用地类型降雨入渗主要补给地表60—70cm土层,前期降雨均匀增加表层土壤含水率,而后期降雨补给深层土壤水分的空间变异性显著增强。(3)刺槐林地产流量及径流系数均显著小于草地和休耕地,且前期含水量对20年刺槐林地的影响较小,而显著影响草地和休耕地径流系数。(4)直径d<1mm的细根显著促进降雨入渗和优先流发育,而d>5mm的粗根与入渗量和基质流量呈显著负相关。较高的土壤初始含水率、容重和粘粒含量会抑制入渗和优先流的发生。研究说明不同土地利用类型将改变降雨入渗产流过程及土壤水运动形式。     

辽东栎林下和开阔地上短柄五加(Acanthopanax brachpus)无性系种群生长的比较研究

研究了分布于开阔地和辽东栎林下短柄五加无性系种群拆散方式、无性系的形态可塑性和分株的死亡年龄,研究结果表明,开阔地上无性系分株的扩散方式为稀疏线型,根茎长度、无性系分株数目,林下和开阔地差异显著,根茎分枝角度、无性系根茎总长无显著性差异。林下分株的死亡年龄显著小于开阔地上无性系分株的死亡年龄。     

Mesenchymal stromal cells ameliorate acute allergic rhinitis in rats

Mesenchymal stromal cells (MSCs) have been extensively investigated as a potential antiinflammatory treatment in many inflammatory‐related diseases; however, it remains unclear whether MSCs could be used to treat acute allergic rhinitis. A rat model of allergic rhinitis was treated with MSCs. The effect of MSCs on the inflammation of allergic rhinitis was evaluated by sneezing, nose rubbing, the pathology of the nasal mucosa, and the expression of interleukin 4, tumour necrosis factor alpha, and immunoglobulin E in the serum of rats. Also, the population of MSCs isolated from umbilical cords of humans was evaluated to determine if they could inhibit the symptoms and inflammation of acute allergic rhinitis in a rat model. We observed that this population of cells inhibited sneezing, nose rubbing, and changes in the pathology of the nasal mucosa. Intriguingly, we observed that MSCs reduced the expression of interleukin 4, tumour necrosis factor alpha, and immunoglobulin E in the serum. Furthermore, MSCs reduced the expression of histamine and the recruitment of macrophages in the nasal mucosa of allergic rhinitis rats. We reasoned that the effect of MSCs on allergic rhinitis might be through its regulation of the secretion of related cytokines from macrophages during the process of acute allergic rhinitis. This work suggested that MSCs from the umbilical cords of humans could be used as a positive clinical therapy for the human disease.     

春兰CgSEP3基因的克隆和表达分析

该研究采用RT-PCR和RACE技术从春兰(Cymbidium goeringii)中分离到1个SEPALLATA3(SEP3)基因。序列分析表明,该基因含有1个732bp的开放阅读框(ORF),共编码243个氨基酸。系统进化树分析显示,该基因是MADS-box基因家族AP1/AGL9组SEP的同源基因,其编码蛋白与其它植物SEP3类蛋白具有较高的一致性,命名为CgSEP3(登录号为KF924272)。实时荧光定量分析表明,CgSEP3在春兰花器官中均有表达,其中在唇瓣、侧瓣和萼片中的表达量较高,在子房和蕊柱中的表达量较低;而且CgSEP3在花发育各个时期都有表达,在1~2cm的花芽中表达量最高,在盛开的花中的表达量最低。研究认为,CgSEP3基因可能在春兰花瓣和萼片的形成过程中具有重要作用。     

循环水养殖系统中凡纳滨对虾肠道微生物对三种复合益生菌制剂的响应

【目的】在循环养殖系统中应用不同的复合益生菌制剂,探讨凡纳滨对虾肠道菌群结构特征及免疫水平发生的变化。【方法】30 d养殖周期结束后,通过平板计数法分析肠道细菌总数和弧菌总数;基于高通量测序技术分析肠道样品V3+V4区菌群特征;采用实时荧光定量PCR技术分析免疫相关因子TLR1和Dorsal基因表达水平,阐述益生菌制剂应用的意义。【结果】益生菌制剂的应用降低了凡纳滨对虾肠道中细菌总数,抑制弧菌的生长,间接预防疾病的发生。不同益生菌制剂从不同程度上优化了凡纳滨对虾肠道菌群结构,提高高质量序列和有效OTU数量,Chao1、Simpson、Shannon指数显示了丰富度和多样性变化,复合益生菌制剂3效果较好。同时,菌群结构得到优化,其中益生菌制剂1组对拟杆菌门含量百分比产生显著影响。Toll受体TLR1和Toll通路中的Dorsal基因m RNA表达受到益生菌制剂的影响,1、3组促进了TLR 1表达,1、2、3组都促进了Dorsal基因表达。【结论】在循环水养殖系统中添加益生菌制剂可优化凡纳滨对虾肠道菌群特征,提高免疫水平,为病害防控和健康养殖提供理论依据。