退化柞蚕林封育对枯落物和表层土壤持水效能的影响

柞蚕林是辽东山区退化最严重的森林类型之一,因多年反复刈割导致生长逐渐衰退、更新能力下降,局部出现空地甚至土壤开始砂化,涵养水源和保持水土等生态功能明显降低。以辽东山区的退化柞蚕林为研究对象,分析了在封育9、12、21a后森林的枯落物及表层土壤持水效能。结果表明:退化柞蚕林经过封育恢复后,封育恢复时间越长,林地枯落物累积量增加的越显著,枯落物持水能力和有效拦蓄降雨能力提高也越明显。对照(未封育)、封育9、12、21a柞蚕林枯落物储量分别为3.69、7.92、8.41 t/hm~2和8.74 t/hm~2;最大持水量分别为6.23、14.71、15.81 t/hm~2和17.18 t/hm~2,有效拦蓄量分别为4.78、10.87、11.70、12.78 t/hm~2。枯落物持水量与浸水时间存在显著的相关关系(P0.001),自然对数模型模拟拟合效果最好(R~20.9)。退化柞蚕林经过封育恢复后,表层土壤水文物理性质的改善随着封育恢复时间的增加而越来越明显,封育9、12和21年柞蚕林表层土壤容重分别比对照退化柞蚕林降低了5.51%、12.60%、17.32%,毛管持水量分别增加了7.01%、28.98%、54.83%,非毛管持水量分别增加了46.14%、126.19%、187.19%。本研究结果说明退化柞蚕林封育能够通过提高其林地枯落物和改善土壤物理性质,增加表层土壤持水效能,对恢复和改善退化柞蚕林地的生态环境、恢复森林生产力具有重要作用。     

基于适宜性分析的黄河首曲地区生态旅游功能区划研究

黄河首曲地区具有突出的生态功能和较高的旅游价值,研究选取距水域湿地距离、草地覆盖情况、森林覆盖情况、海拔高度、坡度和偏远程度6个表征地区自然性的标准,采用GIS技术与层次分析法相结合的方法对黄河首曲地区生态旅游适宜性进行了分析,并结合首曲自然保护区要求对研究区进行了旅游功能区划。研究区生态旅游适宜性可划分为五级,Ⅰ级适宜度最低,适合开发一般的生态旅游或大众旅游,V级地区适宜度最高,原生态景观价值突出,但环境敏感性也高,宜发展严格生态旅游,以最大化保护生态环境。出于协调旅游功能与生态功能的统一以实现地区生态景观可持续利用的目的,研究区被划分为3类功能区、8类功能亚区,且均具有各自特殊的主导和辅助服务功能。研究最后根据各功能区、亚区的特殊服务功能提出了相应的调控措施,以促进生态旅游的合理性规划及未来可持续发展。     

内生真菌感染对宿主羊草抗病性的影响

以感染内生真菌的天然禾草羊草为实验材料,通过体外纯培养条件下的内生真菌、感染内生真菌的离体叶片和在体叶片对3种病原菌的抑菌实验,以探讨内生真菌对宿主植物羊草在抗病性方面的贡献。结果表明:体外纯培养条件下,分离自羊草的内生真菌Epichlobromicola对新月弯孢(Curvularia lunata)、根腐离蠕孢(Bipolaris sorokiniana)和枝孢霉(Cladosporium sp.)这3种病原菌都具有抑制作用,抑菌率分别达56.22%,46.93%和45.15%,且内生真菌培养滤液可以有效抑制这3种病原菌的孢子萌发,平均萌发率分别为30.4%,15.7%和16.4%;宿主植物叶片在离体条件下,内生真菌感染可以有效降低羊草叶片受C.lunata和C.sp.侵染后的病斑数或病斑长度,但对B.sorokiniana不起作用,甚至提高了叶片的病斑数及病斑长度,而离体叶片提取液对不同病原菌均有不同程度的抑制作用;在体条件下,内生真菌均可以通过降低叶片病斑数来增强羊草植株对这3种病原菌的抗性。由此看来,内生真菌E.bromicola对宿主植物羊草在抗病原菌侵染方面有一定的增益作用。     

人工生态系统净化水质模型研究

建立了自来水厂取水口附近的人工生态系统水质模型、研究在水面面积、水生植物放养密度、取水量等改变条件下,取水口处水质的变化特征。这一模型可应用于确定人工生态系统水面积面积,水生植物放养密度等值,以达到满足自来水厂取水口处水质的要求,对模型参数适当确定后,可应用于其它水域。     

TEB/POLQ plays dual roles in protecting Arabidopsis from NO-induced DNA damage

Nitric oxide (NO) is a key player in numerous physiological processes. Excessive NO induces DNA damage, but how plants respond to this damage remains unclear. We screened and identified an Arabidopsis NO hypersensitive mutant and found it to be allelic to TEBICHI/POLQ, encoding DNA polymerase θ. The teb mutant plants were preferentially sensitive to NO- and its derivative peroxynitrite-induced DNA damage and subsequent double-strand breaks (DSBs). Inactivation of TEB caused the accumulation of spontaneous DSBs largely attributed to endogenous NO and was synergistic to DSB repair pathway mutations with respect to growth. These effects were manifested in the presence of NO-inducing agents and relieved by NO scavengers. NO induced G2/M cell cycle arrest in the teb mutant, indicative of stalled replication forks. Genetic analyses indicate that Polθ is required for translesion DNA synthesis across NO-induced lesions, but not oxidation-induced lesions. Whole-genome sequencing revealed that Polθ bypasses NO-induced base adducts in an error-free manner and generates mutations characteristic of Polθ-mediated end joining. Our experimental data collectively suggests that Polθ plays dual roles in protecting plants from NO-induced DNA damage. Since Polθ is conserved in higher eukaryotes, mammalian Polθ may also be required for balancing NO physiological signaling and genotoxicity.     

Pericyte-derived extracellular vesicle-mimetic nanovesicles ameliorate erectile dysfunction via lipocalin 2 in diabetic mice

Diabetes mellitus is one of the main causes of erectile dysfunction (ED). Men with diabetic ED do not respond well to oral phosphodiesterase-5 inhibitors owing to neurovascular dysfunction. Pericyte-derived extracellular vesicle-mimetic nanovesicles (PC-NVs) are known to promote nerve regeneration in a mouse model of cavernous nerve injury. Here, we report that administration of PC-NVs effectively promoted penile angiogenesis and neural regeneration under diabetic conditions, thereby improving erectile function. Specifically, PC-NVs induced endothelial proliferation and migration and reduced cell apoptosis under diabetic conditions. In addition, PC-NVs induced neural regeneration in STZ-induced diabetic mice in dorsal root ganglion and major pelvic ganglion explants in vivo and ex vivo under high-glucose conditions. We found that lipocalin 2 (Lcn2) is a new target of PC-NVs in this process, demonstrating that PC-NVs exert their angiogenic and nerve-regeneration effects by activating MAP kinase and PI3K/Akt and suppressing P53 signaling pathway in an Lcn2-dependent manner. Our findings provide new conclusive evidence that PC-NVs can promote neurovascular regeneration and recovery of erectile function under diabetic conditions via an Lcn2-dependent mechanism. Thus, local administration of PC-NVs may be a promising treatment strategy for the treatment of diabetic ED.     

Depression compromises antiviral innate immunity via the AVP-AHI1-Tyk2 axis

Depression is a serious public-health issue. Recent reports have suggested higher susceptibility to viral infections in depressive patients. However, how depression affects antiviral innate immune signaling remains unknown. Here, we revealed a reduction in expression of Abelson helper integration site 1 (AHI1) in the peripheral blood mononuclear cells (PBMCs) and macrophages from the patients with major depressive disorder (MDD), which leads to attenuated antiviral immune response. We found that depression-related arginine vasopressin (AVP) induces reduction of AHI1 in macrophages. Further studies demonstrated that AHI1 is a critical stabilizer of basal type-I-interferon (IFN-I) signaling. Mechanistically, AHI1 recruits OTUD1 to deubiquitinate and stabilize Tyk2, while AHI1 reduction downregulates Tyk2 and IFN-I signaling activity in macrophages from both MDD patients and depression model mice. Interestingly, we identified a clinical analgesic meptazinol that effectively stimulates AHI1 expression, thus enhancing IFN-I antiviral defense in depression model mice. Our study promotes the understanding of the signaling mechanisms of depression-mediated antiviral immune dysfunction, and reveals meptazinol as an enhancer of antiviral innate immunity in depressive patients.Subject terms: Innate immunity, Ubiquitylation, Cell signalling     

豚草卷蛾与苍耳螟的资源生态位研究

引进的豚草卷蛾和本地的苍耳螟是取食豚草的重要天敌昆虫。为了进一步明确两种天敌种问的竞争作用,定量研究了豚草卷蛾和苍耳螟在寄主植物种类和空间上的生态位指数。结果表明,在寄主植物种类上,豚草卷蛾只取食豚草和苍耳;苍耳螟可取食豚草、苍耳、黄花蒿、向日葵、万寿菊、国庆菊、菊芋、麦杆菊;苍耳螟的生态位宽度指数(Hurbert标准值0．228)明显大于豚草卷蛾(0．069),两者的食物资源生态重叠程度较小(Horn’s指数0．318);豚草卷蛾和苍耳螟对常用资源的利用率分别为93．5％(豚草)和59．3％(苍耳)。在相同寄主植物上,两种天敌的空间生态位表现为：随着寄主植物的生长发育,两种天敌的生态位重叠程度减小;高龄幼虫的生态位宽度指数大于低龄幼虫。在食物生态位上,豚草卷蛾主要取食新发生的幼嫩枝,并且一旦蛀入形成虫瘿后很少发生转移,而苍耳螟除低龄幼虫喜蛀食幼嫩枝外,高龄幼虫的取食部位常常发生转移,从枝型较细的幼嫩枝转向枝型较粗的老龄枝。两种天敌对豚草和苍耳实际选择作用以及对常用资源利用率存在明显差异,因此,形成竞争的程度较小,在对豚草的控制机制上形成互补作用。     

内蒙古根瘤菌的数值分类

对63株新分离的内蒙古根瘤菌与6株来自Rhizobiumleguminosarum及Sinorhizobiummililoti的参比菌株一起进行了数值分类。结果表明：所有测试菌株在67％的相似性水平上分为三个表观群,群Ⅰ包括3株Sinorhizobiummeliloti的参比菌和9株新分离的内蒙古根瘤菌;群Ⅱ包括3株RhizobiumLoguminosarum参比菌和37株新分离的内蒙古根瘤菌;群Ⅲ全部由20株新分离的内蒙古根瘤菌组成。在78％的相似