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991.
992.
目的:研究褪黑素(MLT)对小鼠肝癌细胞株H22的促凋亡作用及其机理。方法:采用丫啶橙(AO)染色、培养液乳酸脱氢酶(LDH)活性检测和流式细胞术(FCM)观察MLT的促凋亡作用;采用RT-PCR方法检测MLT处理前后细胞的p53 mRNA、Fas mRNA的水平。结果:AO染色后H22细胞呈现明显核浓缩的凋亡形态;培养液LDH活性检测及FCM分析均提示MLT诱导H22细胞发生凋亡;RT-PCR结果显示p53、Fas表达增强。结论:MLT能促进H22细胞p53和Fas的表达,从而诱导细胞发生凋亡。 相似文献
993.
拟鹅观草属3种植物的核型研究 总被引:4,自引:0,他引:4
对禾本科小麦族拟鹅观草属物种Pseudoroegneria geniculata、P.geniculata ssp.scythica和P.geniculata ssp.pruinifera的核型进行了研究.结果显示:P.geniculata和P.geniculata ssp.scythica为四倍体物种,P.geniculata ssp.pruinifera为六倍体物种;P.geniculata、P.geniculata ssp.scythica和P.geniculata ssp.pruinifera的核型公式分别为2n=4x=28=18m(2sat)+10sm(2sat)、2n=4x=28=28m(2sat)和2n=6x=42=36m(6sat)+6sm(2sat);P.geniculata和P.geniculata ssp.pruinifera为2A核型,而P.geniculata ssp.scythica为1A核型.研究表明:3种植物的核型存在差异;P.geniculata ssp.pruinifera的核型为首次报道,其核型明显不同于P.geniculata和P.geniculata ssp.scythica. 相似文献
994.
以湘江熬洲断面为例,将该断面水体中总氮浓度及其有关影响因子用三角模糊数来表征.同时,结合己有的模糊线性回归模型成果,构造了带有三角模糊参数的水体中总氮浓度模糊线性回归预测模型.并应用所建模型预测该断面水体中2002-2005年总氮浓度,所得的预测值与已有的实测值之间的相对误差均小于20%,完全满足实际应用对误差的要求,预测合格率为100%,说明这种预测模型在预测河流水体总氮浓度变化中有一定的实用性,为今后开展河流水体中污染物浓度预测提供了新途径. 相似文献
995.
乙型肝炎是一种以局部炎性为主的感染性疾病,乙型肝炎病毒(HBV)感染宿主细胞后可诱导宿主细胞中趋化因子分泌及其受体表达,趋化因子/受体的相互作用进一步介导中性粒细胞、淋巴细胞等向炎症部位聚集,参与组织损伤;同时诱导T、B细胞分化成熟,对乙型肝炎的发展与转归、肝组织的损伤与修复有重要影响。HBV引发的慢性乙型肝炎(CHB)以Th1细胞性炎性反应为主,研究表明乙型肝炎中某些趋化因子在肝脏高表达,其受体CXCR3和CCR5在Th1细胞高表达。趋化因子尤其是CXC和CC亚家族趋化因子在趋化Th1细胞中发挥重要的作用: 相似文献
996.
目的观察褪黑素受体激动剂(NEU-P11)对高糖高脂饲养大鼠脂联素敏感性的影响。方法将30只SD大鼠随机分为对照组(CD组),高糖高脂组(HFSD组),褪黑素组(Mel组),褪黑素受体激动剂组(NEU-P11组)。CD组饲以正常饲料;其余3组饲以高糖高脂饲料。6个月后,给药治疗2个月。治疗期间,Mel组每天注射Mel(4mg/kg);NEU—P11组每天注射NEU-P11(10mg/kg);CD组以及HFSD组注射生理盐水(5ml/kg)。测定糖脂代谢指标并做口服葡萄糖耐量实验(oral glucose tolerant test,OG-TY),Western印迹检测脂联素(adiponectin,APN)在脂肪组织及脂联素受体(AdipoR)在骨骼肌组织中的表达变化。结果高糖高脂饮食可诱导SD大鼠产生胰岛素抵抗,脂联素表达增加。Neu-P11治疗后,胰岛素敏感性增强.脂联素表达降低至正常水平。结论Neu-P11能提高胰岛素敏感性,改善脂联素抵抗。 相似文献
997.
记述纹石蛾科弓石蛾亚科1新纪录属,美赛弓石蛾属Maesaipsyche,及1新种,即细齿美赛弓石蛾Maesaipsyche serrulata Sun et Yang ,sp.nov.(广西),其阳具缺阳基侧突而与Maesaipsyche mekongensis Mey相似,但新种中附肢背缘近端部具齿突、外侧缘具细齿.并记述绒弓石蛾属Parapsyche 1新种,即北京绒弓石蛾Parapsyche beijingensis Sun et Morse,sp.nov.(北京),该种肛上附肢与第10节完全愈合,阳具特别发达,与Parapsyche kchina Schmid相似;但新种阳茎基背突为1对瘤状突,其上着生短刺,阳茎基背突上方具1兜状结构,背面观时端部膨大成圆盘.新种模式标本保存于南京农业大学昆虫标本馆. 相似文献
998.
The foraging habitat selections of brown-eared pheasant (Crossoptilon mantchuricum) and the common pheasant (Phasianus colchicus) were studied in Huanglongshan Nature Reserve Shaanxi, China. Foraging habitat characteristics were measured on the basis of expected differences between species at 183 sites from November to December 2006 and January 2007. The results showed that both species selected foraging habitats with altitude (<1200 m), conifer forest, half sunny and half shady slope, sunny slope, density of trees (<5 individuals/100 m2), cover of shrub (>50%), visibility class (<10%) and distance to water source (<300 m). However, the brown-eared pheasant selected habitats with cover of trees (30–50%), middle or lower slope location, distance to edge of woods (<300 m) and human disturbance (<500 m), and the selection on density of shrub was not observed, compared to the selections on cover of trees (<30%), lower slope location, distance to edge of woods (<500 m) and human disturbance (<300 m), and density of shrub (>500 individuals/100 m2) for common pheasant. We also found that the common pheasant avoid predators by concealment whereas brown-eared pheasant evade predations by running away strategy. 相似文献
999.
Weimin Xi Robert N. Coulson Andrew G. Birt Zong-Bo Shang John D. Waldron Charles W. Lafon David M. Cairns Maria D. Tchakerian Kier D. Klepzig 《生态学报》2009,29(1):69-78
Forest landscape models simulate forest change through time using spatially referenced data across a broad spatial scale (i.e. landscape scale) generally larger than a single forest stand. Spatial interactions between forest stands are a key component of such models. These models can incorporate other spatio-temporal processes such as natural disturbances (e.g. wildfires, hurricanes, outbreaks of native and exotic invasive pests and diseases) and human influences (e.g. harvesting and commercial thinning, planting, fire suppression). The models are increasingly used as tools for studying forest management, ecological assessment, restoration planning, and climate change. In this paper, we define forest landscape models and discuss development, components, and types of the models. We also review commonly used methods and approaches of modeling forest landscapes, their application, and their strengths and weaknesses. New developments in computer sciences, geographic information systems (GIS), remote sensing technologies, decision-support systems, and geo-spatial statistics have provided opportunities for developing a new generation of forest landscape models that are increasingly valuable for ecological research, restoration planning and resource management. 相似文献
1000.
The diets of the wolf Canis lupus, red fox Vulpes vulpes and raccoon dog Nyctereutes ussurienusis Matschie were studied in the grassland of eastern Inner Mongolia from August to October in 2007 and from March to July in 2008. Feces were collected from dens and latrines. The frequency of occurrence and the dry weight of the remains of each food item in the feces were calculated. Livestock (50.65% frequency of occurrence) constituted the bulk of the wolf diet, while small rodents (76.31% frequency of occurrence) were most frequently eaten by the foxes. Small rodents (22.69% frequency of occurrence) were important to the raccoon dogs but they also frequently consumed birds (39.81% frequency of occurrence) and insects (26.39% frequency of occurrence). The wolf was the most omnivorous and the red fox was the least omnivorous of these three kinds of canidae according to the diversity index. The food niches of the wolf and the red fox overlapped more than that of the raccoon dog and other species. These three kinds of canidae shared many resources and consequently competition occurred to them. However, their diets also differed to some extent which helped them to avoid competition. Furthermore, raccoon dogs were dormant in winter when food was scarce, which may be the reason why all these species could coexist in a rather unproductive grassland. 相似文献