HA 纳米载体转hGM-CSF 基因的HepG2 疫苗的抗肿瘤活性研究

目的:评价HA纳米载体转hGM-CSF基因的HepG2疫苗的抗肿瘤活性。方法:SCID小鼠20只腹腔内注射健康志愿者外周血淋巴细胞(1×107/ml)1.0 ml,同时背部皮下接种人肝癌HepG2细胞(1×107ml)0.2 ml。当皮下移植瘤体积长至100 mm3时,随机分四组:Ⅰ组,60Co照射的转染GM-CSF基因的HepG2细胞组,Ⅱ组,60Co照射的HepG2细胞组,Ⅲ组,生理盐水组,Ⅳ组,接种前,每组5只。MTT法检测各组小鼠脾细胞CTL活性,ELISA法检测血清IL-4和IL-12的水平。结果:转染GM-CSF基因的HepG2疫苗组小鼠脾细胞CTL活性明显高于其余组(P<0.05);同时血清Th1类细胞因子IL-12的水平明显升高(P<0.05),而Th2类细胞因子IL-4的水平无统计学意义(P>0.05)。结论:HA纳米载体转hGM-CSF基因的HepG2疫苗可刺激机体产生特异性免疫反应。     

青藏高原高寒草甸初级生产力及其主要影响因素

青藏高原有各类天然草地14×108hm2,其中高寒草甸和高寒灌丛约占青藏高原天然草地面积的50%,占全国草地总面积的16.2%。嵩草草甸是高寒草甸的主体,包括矮嵩草草甸、金露梅灌丛草甸、藏嵩草草甸、小嵩草草甸和高山嵩草草甸等,这5类高寒草甸平均地上生物量分别为354.2、422.4、445.1、227.3和368.5g/m2,地下生物量分别为3389.6、3548.3、11922.7、4439.3、5604.8g/m2,地下与地上生物量的比例分别为10.55、10.15、27.82、14.82和15.21,远大于IPCC(2006)报告中地下/地上生物量比例的默认值(2.8±95%)。地下生物量对气候变化和放牧的反应比地上生物量更敏感,干旱和重度放牧均降低了地下/地上生物量的比例。在极度退化状态下地下/地上生物量的比例2。对于轻度和中度退化的高寒草甸应以围封禁牧为主要恢复措施,但如果结合补播和施肥,则恢复速率会加快;对于重度和极度退化的高寒草甸,由于草地植物群落中优良牧草的比例极低,仅靠自然恢复很难进行恢复或需要的年限很长,所以必须采用人工重建的措施,并结合毒杂草防除和施肥等措施进行恢复,通过建立人工或半人工草地的措施予以重建。     

不同样方尺度下鄱阳湖湿地典型草洲植物种间关联性

为了解群落中优势植物的关联程度和性质随样方尺度的变化,在鄱阳湖湿地典型草洲-南矶湿地国家级自然保护区选取8块样地(大小8 m×8 m,样带间隔100 m,样地间隔80 m),每个样地依次划分为1 m×1 m、2 m×2 m和4 m×4 m等3个样方尺度,利用方差比率法、卡方检验和Jaccard指数检验方法,研究群落优势植物总体关联程度和性质及两两物种对间关联程度和性质随样方尺度扩大的变化。结果表明,该研究区优势物种有灰化薹草(Carex cinerascens)、水田碎米荠(Cardamine lyrata)、蒌蒿(Artemisia selengensis)、通泉草(Mazus japonicus)、菊叶委陵菜(Potentilla tanacetifolia)、南荻(Triarrhena lutarioriparia)和早熟禾(Poa annua)。随样方尺度扩大,物种重要值除灰化薹草先增加后减少以外,其他物种的变化均不显著。7种优势植物组成的21个物种对随样方尺度扩大,植物总体关联性不显著且由负关联转向正关联。在3个样方尺度条件,21个物种对的多呈现不显著关联。随样方尺度的扩大,种间呈显著关联的物种对逐渐减少;种间呈正关联的物种对逐渐增加。Jaccard指数表明,各物种对随样方尺度的扩大,种间关联程度不断增加。这是由于研究区地被植物种类较多,分布频度较低,不同样方尺度下,群落内部资源分布差异以及物种之间的竞争与协同关系所致。     

云南泸定百合8个野生居群的染色体核型分析

用常规压片法,对云南省境内泸定百合(Lilium sargentiae Wilson)8个野生居群的染色体进行了核型分析,结果显示:(1)野生泸定百合8个居群均为二倍体(2n=2x=24),染色体基数为12,共24条染色体,无B染色体;(2)核型类型均为3A,第1、2对染色体均为具中部(m)或近中部(sm)着丝点的大形染色体,且第1对染色体上均具有随体;(3)染色体长度比为1.64～2.26,平均臂比为6.43～8.22,核型不对称系数为79.82% ～ 81.77%。研究表明,泸定百合染色体数相对稳定,染色体变异主要表现在结构变异,各个居群的染色体组成、随体数、随体位置、臂比、染色体长度比及核型不对称系数均有差异,泸定百合各居群间存在明显的核型多态性。     

Circumscription and phylogeny of Saxifraga sect. Ciliatae: Evidence from nrDNA ITS sequences

The largest section of the genus Saxifraga (Saxifragaceae), sect. Ciliatae, consists of 175 morphologically diverse species. This section is mainly distributed in the Qinghai-Tibetan Plateau and adjacent regions of southwest China and more than 80% of the total number of species are endemic to this region. It remains unknown whether this section is monophyletic and up to now no study has been conducted on the infra-sectional phylogeny. In this study, ITS sequences of the nuclear ribosomal DNA were firstly determined for 33 species mainly from this section and related sections. We further downloaded the corresponding sequences of the same DNA region for the other 22 species of Saxifraga and Mitella from GenBank. All sequences were together used to construct the phy-logenetic trees. The main implications of the phylogenetic analyses include: (1) sect. Ciliatae, as traditionally defined, constitutes as a monophyletic clade and its sister group is a well supported clade that includes species from 8 sections such as sect. Porphyrion, sect. Saxifraga and sect. Mesogyne; (2) three morphological subsections, i.e., subsect. Gemmiparae, subsect. Hirculoideae and subsect. Rosulares were tentatively recovered despite the relatively low statistic bootstrap support for the last one; however, subsect. Flagellares and subsect. Hemi-sphaericae were not recognized as separate entities, and nested within subsect. Gemmiparae; (3) subsect. Hircu-loideae and subsect. Rosulares clustered together as sister subclades while subsect. Gemmiparae diverged early. In addition, our results suggest that the paired variation of ITS sequences in sect. Ciliatae is relatively low between the sampled species in spite of their diverse morphology. It is suggested that such a scenario may mirror rapid speciation in this section that probably trigged by the uplifts of the Qinghai-Tibetan Plateau and the extensive selection pressure under the alpine environments.     

广东大中型供水水库的磷污染与富营养化分析

2000年丰水期和枯水期对广东大中型水库的磷污染和富营养化现状进行了调查。结果表明,在调查的20个大中型供水水库中,一半以上的水库受到磷污染,磷污染已成为水库富营养化的重要原因。水库的总磷浓度与水库的营养状态基本一致。水库普遍存在磷限制现象,且枯水期的磷限制现象更为严重。在低温和磷限制条件下,硅藻比绿藻更加有优势。     

颌突外胚间充质干细胞(EMSCs)的体外分离及鉴定

外胚间充质(ectomesenchyme)是一种胚胎发育早期颅面部出现的多能性结构(multipotentstructure),大多数颅面部结构和组织均由其衍生而来,这提示外胚间充质中存在一种干细胞,即外胚间充质干细胞(ectomesenchymalstemcells,EMSCs)。为了分离和鉴定EMSCs,对E125的SD大鼠颌突组织细胞进行了流式细胞学分析,发现其中的外胚间充质细胞表达多种神经谱系和中胚层谱系的标志,包括p75、CD57和nestin等。根据此特点,采用磁细胞分离技术对p75+的颌突外胚间充质细胞进行了分离和克隆培养。克隆分析表明,单个p75+细胞经过10～14d培养,可以形成由两种或两种以上细胞组成的多潜能性克隆(multipotentclone),提示该群外胚间充质细胞具有多潜能性。同时,亚克隆分析表明,多潜能性子克隆中的单个p75+细胞具有再次形成多潜能性克隆的能力,说明这些细胞在体外具有自我更新的能力。这些结果提示,p75+细胞同时具有多潜能性和自我更新能力,因此是外胚间充质干细胞。该干细胞的分离对于口腔颅面部的起源和发育研究无疑具有重要意义。此外,该干细胞的高度可塑性也预示它可以作为一种新的种子细胞,为组织工程皮肤、肌肉、软骨的研究提供新思路。     

Identification and Assessing the Cultivars of Laminaria Lamx. （Phaeophyceae） with Molecular Markers

Molecular markers were used to identify and assess cultivars ofLaminaria Lamx. and to delineate their phylogenetic relationships. Random amplified polymorphic DNA (RAPD) analysis was used for detection. After screening, 11 primers were selected and they yielded 133 bands in all, of which approximately 99.2% were polymorphic. The genetic distances between gametophytes ranged from 0.412 to 0.956.Two clusters were formed with the unweighted pair group method with arithmetic mean (UPGMA) dendrogram based on the simple matching coefficient. All cultivars ofLaminariajaponica Aresch. used for breeding in China fell into one cluster. L.japonica from Japan, L. saccharina (L.) Lam., and L. angustata Kjellm.formed the other cluster and showed higher genetic variation than L. japonica from China. Nuclear ribosomal DNA (rDNA) sequences, including internal transcribed spacers (ITS1 and ITS2) were studied and aligned. The nucleotides of the sequences ranged from 634 to 668, with a total of 692 positions including ITS1, ITS2, and the 5.8S coding region. The phylogenetic tree obtained by the neighbor-joining method favored, to some extent, the results revealed by RAPD analysis. The present study indicates that RAPD and ITS analyses could be used to identify and assess Laminaria germplasm and to distinguish some species and, even intraspecies, in Laminaria.     

植物精油化学成分及其抗菌活性的研究进展

植物精油是一类从植物中萃取的芳香味油状液体,是一类优良的天然抗菌材料。作为抗菌材料,植物精油具有以下优点:具有广谱高效的抗菌活性;具有熏蒸特性、气味芳香;取自天然植物,绿色环保;来源广,提取容易。植物精油因其多种优点,在抗菌领域具有巨大的潜在应用价值。本文从植物精油的分布及化学成分、抗细菌活性和抗真菌活性的研究,以及植物精油化学成分与抗菌活性之间的联系等方面对植物精油的抗菌性能进行评述,以期促进植物精油在抗菌领域的广泛应用,同时给从事植物精油抗菌研究的科研工作者提供参考。