城市绿化竹子生态适应性评价

针对城市绿化竹种要求,选择生长和抗性指标,用集对分析方法,分析和评价华安竹种园200个丛生竹和散混生竹种（或变种）生态适应性,结果表明：丛生竹种中,黄竹、小叶琴丝竹、糯竹、花竹、乡土竹、妈竹、青竿竹、泰竹等在华安生态适应性好,银丝大眼竹、孟竹、大绿竹、麻竹、白节勒竹、撑篙竹、石角竹、大木竹、小刺竹、勃氏甜龙竹、鱼肚腩竹等竹种生态适应性较差,其它竹种适应性中等.而散混生竹种中,衢县苦竹、实心竹、南平倭竹、矮若竹、乌哺鸡竹、毛竹、高节竹、红哺鸡竹、毛环水竹、斑苦竹、满山爆竹、斑箨茶秆竹等竹种适应性较好;缅甸方竹、四季竹、玉山竹篌竹、花毛竹、金镶玉竹等竹种适应性较差,其它竹种适应性中等.     

Design,synthesis and biological evaluation of novel diosgenin–benzoic acid mustard hybrids with potential anti-proliferative activities in human hepatoma HepG2 cells

To discover new lead compounds with anti-tumour activities, in the present study, natural diosgenin was hybridised with the reported benzoic acid mustard pharmacophore. The in vitro cytotoxicity of the resulting newly synthesised hybrids (8–10, 14a–14f, and 15a–15f) was then evaluated in three tumour cells (HepG2, MCF-7, and HeLa) as well as normal GES-1 cells. Among them, 14f possessed the most potential anti-proliferative activity against HepG2 cells, with an IC₅₀ value of 2.26 µM, which was 14.4-fold higher than that of diosgenin (IC₅₀ = 32.63 µM). Furthermore, it showed weak cytotoxicity against GES-1 cells (IC₅₀ > 100 µM), thus exhibiting good antiproliferative selectivity between normal and tumour cells. Moreover, 14f could induce G0/G1 arrest and apoptosis of HepG2 cells. From a mechanistic perspective, 14f regulated cell cycle-related proteins (CDK2, CDK4, CDK6, cyclin D1 and cyclin E1) as well mitochondrial apoptosis pathway-related proteins (Bax, Bcl-2, caspase 9, and caspase 3). These findings suggested that hybrid 14f serves as a promising anti-hepatoma lead compound that deserves further research.     

脊髓分级缺血再灌注损伤模型的建立与病理学评价

目的建立兔脊髓分级缺血再灌注损伤模型和探讨受伤脊髓病理变化可能机制。方法采用肾下腹主动脉阻断法,分别阻断腹主动脉30min、45min和60min后开放,再灌注48h观察神经功能变化以及病理学评价脊髓缺血再灌注损伤程度。结果脊髓缺血时间越长,后肢运动功能损害越明显。伤后2天发现受损脊髓出血、水肿、变性坏死,明显的白细胞浸润以及I-κBα、NF-κBp65、ICAM-l表达增加,脊髓灰质的病理损害严重。再灌注脊髓病理损伤程度依次为缺血60min组>缺血45min组>缺血30min组>假手术组。结论该模型是一种较好的脊髓缺血再灌注损伤模型,阻断肾下腹主动脉血流30min、45min、60min后开放可以较好地反应轻、中、重不同程度缺血再灌注损伤脊髓的病理变化特点。     

海南岛尖峰岭热带山地雨林区26年的气候变化特征——光、水和风因子

采用海南尖峰岭森林生态系统国家野外科学观测研究站天池气象站1980～2005年的地面常规气象观测资料,分析了光、水和风等气候因子的变化趋势,结果发现:26年来,尖峰岭热带山地雨林区年日照时数、年降水量、年蒸发量、年平均相对湿度、年平均水汽压和年平均风速的多年平均值分别为1467.4h、2449.0mm、1248.8mm、88.67%、20.77hPa、1.2m/s.年降水量、平均相对湿度、平均水汽压均呈上升趋势,其中平均水汽压升高趋势明显,每10a增加0.38hPa;日照时数、年蒸发量和年平均风速呈下降趋势,其中平均风速下降明显,每10a减小0.27m/s;月降水量和月蒸发量年代际变化规律不一,但10月份的降水量和9月份的蒸发量下降趋势明显.气候增暖作用分析表明,在全球气候变化背景下,尖峰岭山地雨林区气候增暖作用显著.     

山东蒙山植物多样性及其海拔梯度格局

2007年7月和2008年7月,采用典型取样法,沿海拔梯度对蒙山自然植被进行调查,发现区域地带性植被为麻栎(Quercus acutissima)林,主要植被类型为麻栎群落、赤松(Pinus densiflora)群落、油松(Pinus tabuliformis)群落、日本落叶松(Larix kaempferi)群落、黑松(Pinus thunbergii)群落和刺槐-麻栎(Robinia pseudoacacia-Q.acutissima)群落,麻栎群落略占优势,已具备继续向温带落叶阔叶林演替的条件基础.蒙山各层次植物物种丰富度呈现出草本层>灌木层>乔木层特征,Shannon-Wiener多样性指数和Simpson多样性指数整体规律为灌木层>草本层>乔木层.以蒙山森林群落不同层次的各种物种多样性指数和森林群落总体重要值为测度指标,均判断蒙山植被演替正处于亚顶极群落阶段.蒙山植物多样性沿海拔梯度呈现出近似中海拔高的单峰格局,这除受温度、湿度、人为干扰与面积外,蒙山植被亚顶极群落演替现状与所调查区域仅有800 m的海拔梯度也是重要影响因素.     

基于EPG的麦长管蚜、麦二叉蚜和禾谷缢管蚜取食行为比较

麦长管蚜Sitobion avenae (Fabricius),麦二叉蚜Schizaphis graminum (Rondani)和禾谷缢管蚜Rhopalosiphum padi (Linnaeus)虽然都取食小麦,但其取食部位、传毒能力均有差异。利用EPG研究了3种麦蚜在同一寄主植物上的取食行为,结果显示:(1)禾谷缢管蚜在取食过程中G波出现的时间最早,G波总的持续时间和每次刺探G波的平均持续时间都明显长于麦长管蚜和麦二叉蚜。麦长管蚜第1次E1波的时间、E1波总的持续时间和每次刺探E1波的平均持续时间都明显比麦二叉蚜和禾谷缢管蚜要长。麦二叉蚜E2波总的持续时间和每次刺探E2波的平均持续时间都明显长于麦长管蚜和禾谷缢管蚜。表明3种蚜虫各自拥有不同取食策略。禾谷缢管蚜比其它两种蚜虫需要更多的水分和无机盐,麦长管蚜通过分泌大量唾液增大对食物的利用率,麦二叉蚜通过增加韧皮部取食时间以满足对营养的需要。(2)刺探过程中麦二叉蚜pd波出现的次数为(51.97±7.82)次,高于麦长管蚜的(44.73±4.52)次和禾谷缢管蚜的(32.99±4.22)次。麦二叉蚜pd波Ⅱ-2和Ⅱ-3亚波的时间最长,禾谷缢管蚜最短,三者之间差异达显著水平。表明与其它两种麦蚜相比,麦二叉蚜在取食过程中口针与细胞间的接触频率更高,与细胞内获毒和传毒相关的Ⅱ-3波和Ⅱ-2波持续时间更长,增加了获毒和传毒的几率,是其传毒能力最强的机理。     

研究性实验教学模式的探讨

从教学过程、教学效果等方面探讨了微生物学实验课程实施研究性实验教学模式的必要性以及具体实施的方法。实践表明,研究性实验教学模式对培养学生的创新意识,提高学生的实践能力等方面有积极的作用。     

土壤水分对土壤产生气态氮的厌氧微生物过程的影响

气态氮[一氧化氮(NO)、氧化亚氮(N2O)和氮气(N2)]的释放是土壤氮损失的一种重要途径.硝化和反硝化作用是土壤气态氮损失的主要微生物过程,但是异养硝化作用、共反硝化作用和厌氧氨氧化过程对土壤气态氮损失的贡献尚不清楚.本研究利用15N标记和配对法,结合硝化抑制剂双氰胺(DCD),通过土壤培养试验来量化厌氧条件下各种...     

以蛋白激酶G为靶点的抗结核药物筛选模型

<正>结核分枝杆菌在被巨噬细胞吞噬、形成吞噬体后,可以通过阻止吞噬体的成熟及其与溶酶体的融合,而使其自身不被溶酶体酶降解,从而在巨噬细胞内长期存留下来。此时的细菌代谢活动降至最低,生长繁殖几乎停止,不易被抗菌药物杀灭,这种类似于休眠的长期存活状态被称为"持留"状态。当机体免疫力下降时,     

Interactions between EGFR and EphA2 promote tumorigenesis through the action of Ephexin1

The cell signaling factors EGFR, EphA2, and Ephexin1 are associated with lung and colorectal cancer and play an important role in tumorigenesis. Although the respective functional roles of EGFR and EphA2 are well known, interactions between these proteins and a functional role for the complex is not understood. Here, we showed that Ephexin1, EphA2, and EGFR are each expressed at higher levels in lung and colorectal cancer patient tissues, and binding of EGFR to EphA2 was associated with both increased tumor grade and metastatic cases in both cancer types. Treatment with Epidermal Growth Factor (EGF) induced binding of the RR domain of EGFR to the kinase domain of EphA2, and this binding was promoted by Ephexin1. Additionally, the AKT-mediated phosphorylation of EphA2 (at Ser897) promoted interactions with EGFR, pointing to the importance of this pathway. Two mutations in EGFR, L858R and T790M, that are frequently observed in lung cancer patients, promoted binding to EphA2, and this binding was dependent on Ephexin1. Our results indicate that the formation of a complex between EGFR, EphA2, and Ephexin1 plays an important role in lung and colorectal cancers, and that inhibition of this complex may be an effective target for cancer therapy.Subject terms: Oncogenes, Cancer models