关于三氧化二砷(As_2O_3)联合药物治疗肝癌的研究进展

实验与临床研究已证实,As2O3能有效治疗急性早幼粒细胞性白血病(APL)。在此基础上.As2O3抗肝癌作用的研究报告日益增多。研究表明As2O3的抗肝癌效力呈剂量-时间效应关系,但作用时间越长及药物浓度越大,As2O3的毒副作用越大。为实现As2O3低毒高效的抗肿瘤目的,联合用药引起关注。本文通过查阅94年至今国内外有关As2O3药物联合治疗肝癌的文献,对As2O3联合药物治疗肝癌予以综述。     

抗噬菌体菌株C224发酵生产2KG的条件试验

以ZKG生产菌株球状节杆菌K1022为出发菌株,选育出的抗噬菌体菌株C224发酵条件试验的实验结果表明:C224菌能利用淀粉水解糖、葡萄糖酸钙、葡萄糖发酵产生2KG;以葡萄糖为原料发酵生产2KG的条件为:接种量8％以上,250mL摇瓶装量20mL,31℃265r/min,振荡培养72h;发酵最佳配比组成为:葡萄糖18％,玉米浆1.65％,尿素0％,KH_2PO_4 0.0015％,CaCO_3 5％。     

小鼠脑缺血再灌注模型的构建及条件优化

目的:构建小鼠的脑缺血再灌注模型,并对其进行优化。方法:通过对线栓法缺血再灌注脑损伤模型的各个因素的对比实验,在线拴位置、线径、进线深度、小鼠种类等方面对该方法进行了优化改进。结果:造模后的脑片经TTC染色,梗死区域清晰;神经功能评分的体征明显。现有条件下构建的小鼠MCAO模型,成功率可以达到80%以上,成活率可以达到90%以上。与对照组相比,小鼠MCAO模型组血清SOD活性及MDA水平有显著变化(P0.01)。结论:经改进和优化,小鼠脑缺血再灌注模型的成功率和成活率大大提高且症状明显,对缺血缺氧性神经损伤研究具有一定的参考价值。     

NaCl胁迫对宁夏枸杞幼苗根系质膜和液泡膜H+-ATPase活性的影响

以宁夏枸杞为材料,研究NaCl胁迫下枸杞幼苗组织含水量、干物质重量、无机离子分布、质膜透性、丙二醛 (MDA)含量及幼根质膜、液泡膜H -ATPase活性和耐盐性之间的关系。结果表明,在0．3％NaCl胁迫下,干物质重量、质膜透性、MDA含量略有增加,组织含水量略有下降;随着NaCl胁迫强度的增加,Na 、Cl-含量逐渐增加, K 含量则呈现下降的趋势;质膜透性增大与MDA含量升高呈显著正相关;质膜和液泡膜H -ATPase活性逐渐增加,且液泡膜H -ATPase活性显著高于质膜H -ATPase活性,表明枸杞具有较强的抗盐性。     

基于多元回归树的常绿阔叶林群丛数量分类——以古田山24公顷森林样地为例

常绿阔叶林植被分类一直是植被生态学研究中的难题,尤其是基本单位——群丛的分类。该文以地形因子和物种组成数据为变量的多元回归树方法,将浙江古田山24hm2森林监测样地的森林群落分为3个群丛。所得群丛既反映了群落在时间和空间上的相对间断分布,也符合植被分类基本单位的特点,为常绿阔叶林的群丛分类提供了新思路。并首次引入了指示值算法,解决了以往指示种无法量化的难题。最终以优势层优势种为主、下木层指示种为辅的命名原则,将3个群丛命名为:1)石斑木(Raphiolepis indica)+柳叶蜡梅(Chimonanthus salicifolius)-格药柃(Eurya muricata)+赤楠(Syzygium buxifolium)-木荷(Schima superba)+甜槠(Castanopsis eyrei)群丛;2)映山红(Rhododendron simsii)+满山红(Rhododendron mariesii)-短柄枹(Quercus serrata var.brevipetiolata)+灰白蜡瓣花(Corylopsis glandulifera var.hypoglauca)-马尾松(Pinus massoniana)+甜槠群丛;3)短尾越桔(Vaccinium carlesii)+毛花连蕊茶(Camellia fraterna)-杨梅叶蚊母树(Distylium myricoides)+浙江新木姜子(Neolitsea aurata)-木荷+甜槠群丛。     

Extremely low levels of genetic diversity in the terrestrial orchid Epipactis thunbergii (Orchidaceae) in South Korea: implications for conservation

Levels of allozyme variation, population genetic structure, and fine-scale genetic structure (FSGS) of the rare, both sexually and clonally reproducing terrestrial orchid Epipactis thunbergii were examined for eight ( N  = 734) populations in a 20 × 20-km area in South Korea. Twenty-three putative allozyme loci resolved from 15 enzyme systems were used. Extremely low levels of allozyme variation were found within populations: the mean frequency of polymorphic loci was 3.8% [isocitrate dehydrogenase ( Idh-2 ) with two alleles was polymorphic across populations], the mean number of alleles per locus was 1.04, and the mean expected heterozygosity was 0.013. The overall fixation index was not significantly different from zero ( F _IS = 0.069), although the species is self-compatible. However, a significantly high degree of population differentiation was found between populations at Idh-2 ( F _ST = 0.388) in the studied area. Furthermore, spatial autocorrelation analyses revealed a significant FSGS (up to 3 m) within populations. These observations suggest that the main explanatory factors for the extremely low levels of genetic diversity and the shaping of the population genetic structure of E. thunbergii are genetic drift as a result of a small effective population size, a restricted gene flow, and the isolation of populations. Considering the current genetic structure of E. thunbergii , three guidelines are suggested for the development of conservation strategies for the species in South Korea: (1) protection of habitats of standing populations; (2) prohibition by law of any collection of E. thunbergii ; and (3) protection of nearby pollinator populations, given the fact that fruit set in natural habitats is very low.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 161–169.     

Role of ants in structuring the aphid community on apple

1. The aphids Dysaphis plantaginea Passerini, Aphis spp. (Aphis pomi De Geer and Aphis spiraecola Patch), and Eriosoma lanigerum Hausmann are commonly found together in apple orchards. Ants establish a mutualistic relationship with the myrmecophilous aphids D. plantaginea and Aphis spp. but not with E. lanigerum. 2. Field surveys and one experiment manipulating the presence of ants and the aphid species were conducted to test the hypothesis that ants play a role in structuring the community of these aphids on apple. 3. Ants tended D. plantaginea and Aphis spp. but not E. lanigerum colonies. In the field, D. plantaginea performed better in the presence of ants while no effect was observed in Aphis spp. Contrarily, populations of Aphis spp. in the manipulative experiment performed better in the presence of ants while no differences were observed for D. plantaginea. Such differences between field and manipulative conditions could be related to thermal tolerance, phenology, and life cycles. In contrast, populations of E. lanigerum were reduced in the presence of ants. 4. Ants also had a significant negative effect on the abundance of natural enemies, which could partially explain the benefits to the tended aphids. However, while ants did not provide a benefit to Aphis spp. when it was reared alone, in the presence of other species ant attendance increased Aphis abundance by 256% and simultaneously reduced E. lanigerum abundance by 63%. Therefore, ants benefited Aphis by reducing competition with other aphid species, which involves a different mechanism, explaining the benefit of ant attendance. Considering all the aphid species together, ants had a net positive effect on aphid abundance, which was consequently considered harmful for the plant. 5. Our results highlighted the role that ants play in structuring apple aphid communities and give support to the observed pattern that ants can benefit tended aphids while simultaneously reducing the abundance of untended herbivores.     

黑熊种群年龄结构和生命表初探

本文以四川野生黑熊（Ｓｅｌｅｎａｒｃｔｏｓ ｔｈｉｂｅｔａｎｕｓ）的头骨标本为基础材料,结合养熊场所积累的有关黑熊的年龄构成、繁殖、死亡等资料,运用数学分析方法对四川黑熊种群的年龄儿性比进行了分析研究,编制出黑熊的静态生命表,分析了黑熊种群的内禀增长能力,并得出了野生黑熊种群的平均期望寿命为６．３６６岁,净生殖率（Ｒｏ）为１．６９３２５,平均世代时间（Ｔ）为１１．５４４年,内禀增长率（ｒｍ）为０．     

草本凋落物与尿素联合修复对油污土壤生物化学性质的影响

为研究植物残体配合施氮对石油污染土壤生物学和化学性质的综合修复能力,以紫花苜蓿(Medicago sativa)、铁杆蒿(Artemisia gmelinii)和小冠花(Coronilla varia)3种广泛分布于陕北石油污染区的草本植物凋落物为对象,分别在配合施氮调节土壤C∶N为25∶1和不配合施氮的条件下,将其与45.37 g/kg的重度石油污染土壤混合,在20—25℃、恒湿条件下进行为期180 d的室内修复试验,检测上述处理对油污土壤微生物数量、11种土壤水解酶和氧化还原酶活性以及速效N、P和K含量的影响。结果表明:(1)3种凋落物处理均可显著提高污染土壤中放线菌和真菌数量,蔗糖酶、淀粉酶、纤维素酶、木聚糖酶、脲酶、蛋白酶、磷酸酶、多酚氧化酶、过氧化氢酶和过氧化物酶活性以及速效养分含量,并显著降低土壤总石油烃含量。(2)配合施氮总体上显著强化了凋落物对污染土壤生化性质的修复作用,但对凋落物处理下木聚糖酶、脲酶、蛋白酶和脱氢酶活性和微生物数量的恢复可能产生不利影响。(3)单纯使用凋落物作为调理剂可以更为全面的修复油污土壤受损生化性质,具有高N和P含量、较低C/N、C/P比以及较低...     

EGFR配体生物学效应的多样性

表皮生长因子受体（epidermal growth factor receptor, EGFR）的配体作为一类重要的信号分子参与了细胞功能的调节,并且和机体发育、器官形成、组织修复与稳态维持,以及疾病的发生密切相关。虽然这些信号分子具有序列和结构上的相似性,但由于这些信号分子结构上的细微差异以及它们受体信号传导上的复杂性,造成了这些信号分子（配体）生物学效应的多样性。目前,从结构和机制上,对于单个信号分子的生物学效应已有较为深入的研究,但这些信号分子之间以及信号分子与受体之间的调控网络较为复杂,并且这种调控网络对信号的精细、有序和多样化转导至关重要。本文对EGFR配体的结构及配体生物学效应多样性的分子机制进行回顾,并对未来的研究方向提出展望。