香溪河官庄坪库湾叶绿素a 及初级生产力的分布特征

2005年2月—4月对三峡库区香溪河进行了定点初级生产力及相关影响因子的研究,分析了官庄坪库湾叶绿素a含量和初级生产力的时空分布特征。结果表明,叶绿素a含量、初级生产力在各水层的变化具有相同的周期性,均存在5个峰值,平均每个周期为7—10d左右,但两者不同步。官庄坪测站的真光层深度为10m左右,介于湖泊与海洋之间,光补偿点为4—5m。初级生产力最大值出现在水下0.5m处,并沿物理深度逐渐降低;叶绿素a含量最大值则出现在水下2m处。水温的垂直变化在后期差异明显,各水层日平均水温增量(ΔT/d)与平均毛初级生产、净初级生产存在极显著的相关性。     

荔枝草花的形态发生

在体式显微镜系统观察的基础上,对唇形科鼠尾草属植物荔枝草(Salvia plebeiaR.Br.)的花发育过程进行了扫描电镜观察.发现荔枝草的轮伞花序由多数交互对生的聚伞花序单位组成,花器官发育形式为向心式",各部分花器官从外向内依次形成;共形成4个雄蕊原基,其中2个雄蕊原基在形成后不再发育,另2个雄蕊原基每个均发育出1可育药室和1不育药室,不育药室膨大连接,并在花成熟之前参与组成特殊杠杆结构;子房四深裂"的形成实际是由4个原基分别发育,而后相互靠拢而成.     

Determination of ritodrine in human plasma by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry

A simple and sensitive HPLC/MS/MS method was developed and evaluated to determine the concentration of ritodrine (RTD) in human plasma. Liquid-liquid extraction with ethyl acetate was employed as the sample preparation method. The structural analogue salbutamol was selected as the internal standard (IS). The liquid chromatography was performed on a Hanbon Sci. & Tech. Lichrospher CN (150 mm x 4.6 mm, i.d., 5 microm) column (Hanbon, China) at 20 degrees C. A mixture of 0.03% acetic acid and methanol (50:50, v/v) was used as isocratic mobile phase to give the retention time 3.60 min for ritodrine and 2.94 min for salbutamol. Selected reaction monitoring (SRM) in positive ionization mode was employed for mass detection. The calibration functions were linear over the concentration range 0.39-100 ng mL(-1). The intra- and inter-day precision of the method were less than 15%. The lower limit of quantification was 0.39 ng mL(-1). The method had been found to be suitable for application to a pharmacokinetic study after oral administration of 20mg ritodrine hydrochloride tablet to 18 healthy female volunteers. The half-life is 2.54+/-0.67 h.     

Gold nanorods targeted to delta opioid receptor: plasmon-resonant contrast and photothermal agents

Molecularly targeted gold nanorods were investigated for applications in both diagnostic imaging and disease treatment with cellular resolution. The nanorods were tested in two genetically engineered cell lines derived from the human colon carcinoma HCT-116, a model for studying ligand-receptor interactions. One of these lines was modified to express delta opioid receptor (deltaOR) and green fluorescent protein, whereas the other was receptor free and expressed a red fluorescent protein, to serve as the control. Deltorphin, a high-affinity ligand for deltaOR, was stably attached to the gold nanorods through a thiol-terminated linker. In a mixed population of cells, we demonstrated selective imaging and destruction of receptor-expressing cells while sparing those cells that did not express the receptor. The molecularly targeted nanorods can be used as an in vitro ligand-binding and cytotoxic treatment assay platform and could potentially be applied in vivo for diagnostic and therapeutic purposes with endoscopic technology.     

Single and dual amino acid substitutions in TCR CDRs can enhance antigen-specific T cell functions

Single and dual amino acid substitution variants were generated in the TCR CDRs of three TCRs that recognize tumor-associated Ags. Substitutions that enhance the reactivity of TCR gene-modified T cells to the cognate Ag complex were identified using a rapid RNA-based transfection system. The screening of a panel of variants of the 1G4 TCR, that recognizes a peptide corresponding to amino acid residues 157-165 of the human cancer testis Ag NY-ESO-1 (SLLMWITQC) in the context of the HLA-A*02 class I allele, resulted in the identification of single and dual CDR3alpha and CDR2beta amino acid substitutions that dramatically enhanced the specific recognition of NY-ESO-1(+)/HLA-A*02(+) tumor cell lines by TCR gene-modified CD4(+) T cells. Within this group of improved TCRs, a dual substitution in the 1G4 TCR CDR3alpha chain was identified that enhanced Ag-specific reactivity in gene-modified CD4(+) and CD8(+) T cells. Separate experiments on two distinct TCRs that recognize the MART-1 27-35 (AAGIGILTV) peptide/HLA-A*02 Ag complex characterized single amino acid substitutions in both TCRs that enhanced CD4(+) T cell Ag-specific reactivity. These results indicate that simple TCR substitution variants that enhance T cell function can be identified by rapid transfection and assay techniques, providing the means for generating potent Ag complex-specific TCR genes for use in the study of T cell interactions and in T cell adoptive immunotherapy.     

Effects of small interfering RNAs targeting MAPK1 on gene expression profile in HeLa cells as revealed by microarray analysis

The mitogen activated protein kinases (MAPK) signaling cascade plays an important role in cell life. We proved that small interfering RNAs targeting MAPK1 (siRNA-2) could inhibit HeLa cell growth, but the effects of siRNA-2 on gene expression profile were unclear. Using Affymetrix GeneChip HG-U133A 2.0, we identified the long-term changes for 48h in gene expression profile in HeLa cell treated by siRNA-2. The results showed that expressions of 181 genes were altered by siRNA-2 and were divided into two groups: (i) one group showed downregulation by siRNA-2, including the proliferation associated genes, small G protein, cytoskeleton associated protein and extracellular matrix associated protein; and (ii) the other group showed upregulation by siRNA-2, including interferon response genes, OAS family, TRIM family and apoptosis associated genes. The results of Real-time quantitative PCR for MAPK1, NUP188, P38, STAT1, STAT2, MPL and OAS1 were consistent with that of gene chip. Two networks were found to react substantially to the downregulation of MAPK1 by siRNA-2. One of the networks regulates cell growth through cell-cycle control, apoptosis and cytoskeleton. The other network is related to interferon-like response. Our findings suggest that siRNA-mediated downregulation of MAPK1 could be an attractive strategy for cancer therapy.     

抗氧化剂在糖尿病中的应用研究进展

氧化应激是自由基的促氧化与机体的抗氧化失衡造成的.自由基的高反应活性可以使细胞组分发生化学变化,并导致脂质过氧化.越来越多的证据表明:糖尿病患者体内活性氧物质明显增多,并且抗氧化防御系统功能紊乱.抗氧化剂可以降低糖尿病患者体内的氧化应激水平,清除自由基并改善抗氧化防御体系,所以将抗氧化剂应用于糖尿病是可行的.许多抗氧化剂已经用于糖尿病的研究与治疗,本文主要将作用于糖尿病的各种抗氧化剂做一综述.     

中国5个地方牦牛品种遗传多样性的微卫星分析

本文以大额牛（Bos frontalis）为外群,应用16对微卫星DNA标记结合荧光-多重PCR技术,评估了5个中国地方牦牛（Bos grunniens）（帕里牦牛、斯布牦牛、西藏高山牦牛、麦洼牦牛和九龙牦牛）品种内遗传变异和品种间遗传关系。6个群体的16个微卫星座位上共检测到159个等位基因,其中有33个等位基因为5个牦牛品种所特有。6个群体的有效等位基因数（Ne）在2.2043-3.2754之间,平均杂合度（H）在0.4858-0.6153之间,平均多态信息含量（PIC）在0.4230-0.5711之间。5个牦牛品种的微卫星座位有丰富的遗传多样性;而大额牛的遗传多样性相对较贫乏。5个牦牛群体间的遗传分化系数（Gst）为0.0527,表明牦牛亚群体间遗传分化水平很低。采用邻近结合法构建聚类图和模糊聚类分析表明,5个牦牛品种分为两大类,其中斯布牦牛、西藏高山牦牛、帕里牦牛和麦洼牦牛为一大类,九龙牦牛为一类。研究结果将为中国地方牦牛品种的保护和利用提供重要的理论依据。     

动物学综合实验在教学中培养探究性的实践

以动物学综合实验--家鸡脑标本的制作与观察为例,从药品的配制、实验材料的准备、实验整个操作程序的设计,到最后的实验结果,让学生独立完成.起到了指导学生探究和掌握科学方法的作用,让学生在体验科学探究的过程中,获得初步的科学探究能力,培养其探索和创新意识,从而提高生物科学素养.