基于RS/GIS公路路域水土流失动态变化的研究——以榆靖高速公路为例

基于RS数据源,利用ERDAS和ArcGIS软件技术,对榆靖高速公路两侧300m范围水土流失动态变化开展研究。通过遥感图像数字处理方法,提取对水土流失起主导作用的植被覆盖度、土地利用类型、沟谷密度等因子;在矢量化等高线数据的基础上生成数字高程模型(DEM),提取地形坡度因子,将这4个因子在GIS中进行空间叠加分析。参照《土壤侵蚀分级标准》,生成研究区不同时段水土流失强度等级图,利用GIS属性统计功能对公路沿线各等级水土流失区面积进行统计,参照研究区不同侵蚀类型的土壤侵蚀模数,得出1996年和2006年公路沿线各流失区的水土流失量,并对公路沿线水土流失动态变化进行分析。结果表明：榆靖高速公路修建后沿线600m范围水土流失总量减少19.26万t/a,水土流失呈减弱趋势。公路施工期导致水土流失增强的各种因素随着营运期固化路面的形成而逐渐消失,防沙固沙和生态恢复等措施有效改善了公路路域生态环境,对公路沿线水土流失防治起到了积极作用。     

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.     

Genome‐wide distribution and functions of the AAE complex in epigenetic regulation in Arabidopsis

Heterochromatin is widespread in eukaryotic genomes and has diverse impacts depending on its genomic context. Previous studies have shown that a protein complex, the ASI1‐AIPP1‐EDM2 (AAE) complex, participates in polyadenylation regulation of several intronic heterochromatin‐containing genes. However, the genome‐wide functions of AAE are still unknown. Here, we show that the ASI1 and EDM2 mostly target the common genomic regions on a genome‐wide level and preferentially interacts with genetic heterochromatin. Polyadenylation (poly(A) sequencing reveals that AAE complex has a substantial influence on poly(A) site usage of heterochromatin‐containing genes, including not only intronic heterochromatin‐containing genes but also the genes showing overlap with heterochromatin. Intriguingly, AAE is also involved in the alternative splicing regulation of a number of heterochromatin‐overlapping genes, such as the disease resistance gene RPP4. We provided evidence that genic heterochromatin is indispensable for the recruitment of AAE in polyadenylation and splicing regulation. In addition to conferring RNA processing regulation at genic heterochromatin‐containing genes, AAE also targets some transposable elements (TEs) outside of genes (including TEs sandwiched by genes and island TEs) for epigenetic silencing. Our results reveal new functions of AAE in RNA processing and epigenetic silencing, and thus represent important advances in epigenetic regulation.     

高温对水稻叶片蛋白质表达的影响

为明确高温对耐热性不同水稻品种叶片蛋白质表达的影响,以耐热性不同的2个籼稻品种双桂1号(不耐热)和黄华占(耐热)为材料,分别于苗期、减数分裂期及抽穗(始穗后0—10d)和灌浆早期(始穗后11—20d)进行高温处理,之后取材并采用双向凝胶电泳技术研究高温对不同水稻品种叶片蛋白质表达的影响。结果表明,高温胁迫导致叶片中蛋白质的变化呈4种状况:新蛋白质的产生,一些蛋白质表达量上调,一些蛋白质的表达被抑制,一些蛋白质表达量下调。蛋白质表达变化在两品种以及4个处理时期的表现不同,总体表现为在热敏感品种中表达谱发生变化的蛋白质总数高于耐热品种。质谱分析表明,差异蛋白质主要涉及光合作用和信号转导,该类蛋白质在热敏感品种中表现为不表达或表达量下降,而在耐热品种则表现为有新诱导的蛋白质的产生或表达量上调,表明参与光合作用和信号转导的蛋白质在水稻耐热机制中发挥了重要作用。     

脂肪组织在炎症发生中的作用

脂肪组织不仅是能量储备场所,还是活跃的内分泌器官。近年来的研究已经阐明,脂肪组织可以分泌多种炎症因子,参与原发性炎症。因此阐明脂肪组织在炎症发生中的作用,将有助于重新认识一些疾病的发病机制,为疾病的防治提供新的思路。     

盐角草内生真菌分离鉴定及抑制水产腐败细菌菌株的筛选

盐角草是一种耐盐植物,有重要的食用、药用价值.为研究盐角草的内生真菌及其活性次生代谢产物的多样性,该文对采集于广西北部湾沿海盐角草的内生真菌进行分离纯化,采用RAPD对内生真菌多样性进行分析,采用ITS基因序列对内生真菌进行鉴定,并对内生真菌提取物抑制等3种水产腐败细菌的活性进行筛选.结果表明:(1)从北部湾盐角草植物...     

HPLC测定灵芝子实体水提物及相关产品中三萜的含量

灵芝药品大多以灵芝子实体水提物为原料,为快速准确测定灵芝子实体水提物及相关产品中三萜的含量,建立了具有较好分离效果的HPLC分析测定方法。通过优化色谱柱和洗脱条件,优选出Agilent Zorbax SB-Aq C18色谱柱(250 mm×4.6 mm,5μm),以乙腈-乙酸水溶液(0.01%)为流动相梯度洗脱,流速为1.0 mL/min,检测波长252 nm,柱温30℃,该条件下灵芝酸A、灵芝酸F等10种灵芝酸得到较好的分离。方法学考察显示该分析方法精密度、重复性、稳定性和加样回收率的RSD值均小于5%,可以用于灵芝酸C2、灵芝酸G、灵芝烯酸B、灵芝酸B等10种灵芝酸的定量检测。通过对灵芝子实体原料、水提物和市售灵芝产品中10种三萜类成分分析发现,灵芝子实体水提物中均含有这10种三萜,含量为2.52%–6.83%,较子实体原料大幅提高,市售的灵芝产品中的三萜含量为0.27%–0.84%。该方法的建立为灵芝水提物及其产品质量标准的建立奠定基础。     

VEGF/VEGFR-Targeted Therapy and Immunotherapy in Non-small Cell Lung Cancer: Targeting the Tumor Microenvironment

Non-small cell lung cancer (NSCLC) is the leading cause of death by cancer worldwide. Despite developments in therapeutic approaches for the past few decades, the 5-year survival rate of patients with NSCLC remains low. NSCLC tumor is a complex, heterogeneous microenvironment, comprising blood vessels, cancer cells, immune cells, and stroma cells. Vascular endothelial growth factors (VEGFs) are a major mediator to induce tumor microvasculature and are associated with the progression, recurrence, and metastasis of NSCLC. Current treatment medicines targeting VEGF/VEGF receptor (VEGFR) pathway, including neutralizing antibodies to VEGF or VEGFR and receptor tyrosine kinase inhibitors, have shown good treatment efficacy in patients with NSCLC. VEGF is not only an important angiogenic factor but also an immunomodulator of tumor microenvironment (TME). VEGFs can suppress antigen presentation, stimulate activity of regulatory T (Treg) cells, and tumor-associated macrophages, which in turn promote an immune suppressive microenvironment in NSCLC. The present review focuses on the angiogenic and non-angiogenic functions of VEGF in NSCLC, especially the interaction between VEGF and the cellular components of the TME. Additionally, we discuss recent preclinical and clinical studies to explore VEGF/VEGFR-targeted compounds and immunotherapy as novel approaches targeting the TME for the treatment of NSCLC.     

灰飞虱与褐飞虱种内和种间密度效应比较

在人工气候室内比较研究了灰飞虱和褐飞虱在汕优63和秀水11上的种内和种间密度效应对其主要生物学参数的影响,结果表明两种稻飞虱均存在显著的种内竞争,主要表现为随着密度增加,若虫发育历期延长、若虫羽化率下降、雌成虫寿命缩短、每雌产卵量下降。种内密度效应与稻飞虱种类和寄主品种有显著互作关系,灰飞虱种内竞争较褐飞虱明显,二者在适宜寄主上种内竞争更为明显。同时,两种稻飞虱存在着显著的种间密度效应,主要表现为异种存在时的促进作用,即异种共存时若虫历期缩短、若虫羽化率提高、雌虫寿命延长、每雌产卵量增加。种间密度效应也与稻飞虱种类和寄主品种有显著互作关系,两种共存对灰飞虱的有利作用显著大于对褐飞虱的有利作用,在欠适宜寄主上种间互利效应更为明显。最后,本文对稻飞虱种内和种间密度效应的机制和进化意义进行了讨论。