用于丙型肝炎病毒抗原测定的SiO_2载体的制备及其性质分析

为了优化将抗体偶联在二氧化硅试管表面上以便进行丙型肝炎抗原检测的分析系统,本研究通过氨基硅烷的活化作用,在玻璃表面形成活化的氨基,以戊二醛作为化学交联试剂,在已硅化的玻璃表面固定丙肝单克隆抗体,并进行丙肝抗原(HCAg)的测定。结果显示,通过条件优化实验,发现以10%(V/V)的氨基硅烷水溶液处理玻璃试管3h后,再用3%(V/V)的戊二醛水溶液交联丙肝单克隆抗体2h,可以得到固定效果较好,非特异性较低的玻璃载体,对HCAg可测至1μg/L。可见,用该方法制备的玻璃载体可为进一步建立新的HCAg磁性免疫检测系统提供理论和实验依据。     

Genetic variation within and among populations of a wild rice Oryza granulata from China detected by RAPD and ISSR markers

Genetic variation within and between five populations of Oryza granulata from two regions of China was investigated using RAPD (random amplified polymorphic DNA) and ISSR (inter-simple sequence repeat amplification) markers. Twenty RAPD primers used in this study amplified 199 reproducible bands with 61 (30.65%) polymorphic; and 12 ISSR primers amplified 113 bands with 52 (46.02%) polymorphic. Both RAPD and ISSR analyses revealed a low level of genetic diversity in wild populations of O. granulata. Furthermore, analysis of molecular variance (AMOVA) was used to apportion the variation within and between populations both within and between regions. As the RAPD markers revealed, 73.85% of the total genetic diversity resided between the two regions, whereas only 19.45% and 6.70% were present between populations within regions and within a population respectively. Similarly, it was shown by ISSR markers that a great amount of variation (49.26%) occurred between the two regions, with only 38.07% and 12.66% between populations within regions and within a population respectively. Both the results of a UPGMA cluster, based on Jaccard coefficients, and pairwise distance analysis agree with that of the AMOVA partition. This is the first report of the partitioning of genetic variability within and among populations of O. granulata at the DNA level, which is in general agreement with a recent study on the same species in China using allozyme analysis. Our results also indicated that the percentage of polymorphic bands (PPB) detected by ISSR is higher than that detected by RAPD. It seems that ISSR is superior to RAPD in terms of the polymorphism detected and the amplification reproducibility. Received: 29 March 2000 / Accepted: 15 May 2000     

Ultrasound-induced biophysical effects in controlled drug delivery

Ultrasound is widely used in biomedical engineering and has applications in conventional diagnosis and drug delivery. Recent advances in ultrasound-induced drug delivery have been summarized previously in several reviews that have primarily focused on the fabrication of drug delivery carriers. This review discusses the mechanisms underlying ultrasound-induced drug delivery and factors affecting delivery efficiency, including the characteristics of drug delivery carriers and ultrasound parameters. Firstly, biophysical effects induced by ultrasound, namely thermal effects, cavitation effects, and acoustic radiation forces, are illustrated. Secondly, the use of these biophysical effects to enhance drug delivery by affecting drug carriers and corresponding tissues is clarified in detail. Thirdly, recent advances in ultrasound-triggered drug delivery are detailed. Safety issues and optimization strategies to improve therapeutic outcomes and reduce side effects are summarized. Finally, current progress and future directions are discussed.

     

gacS基因插入失活对绿针假单胞菌G-05的两种胞外次生代谢物合成的影响

一株来自大棚温室甜椒根际的绿针假单胞菌Pseudomonas chlororaphis G-05,可分泌抗生物质吩嗪-1-羧酸,并具有抑制辣椒疫霉的生物防治功效。【目的】为了系统研究该菌株的生物防治功能及抗生物质合成与分泌机制。【方法】首先通过生化法和16S rDNA同源比对法对该菌株进行系统分类的初步鉴定,再根据基因的同源性从G-05基因组DNA中克隆长1.4 kb的gacS基因的部分保守区段,采用抗庆大霉素基因（gentamycin resistance cassette, aacC1）插入失活的策略构建了该基因突变株G-05S。【结果】在King’ s B（KMB）或PPM培养基中,突变株G-05S合成吩嗪-1-羧酸的能力受到明显抑制。然而,突变株G-05S分泌的吲哚乙酸与野生株相比无显著差异。互补实验表明,gacS基因的表达可以使突变株G-05S的吩嗪-1-羧酸的合成恢复到野生株水平。【结论】由此推测,GacS(Global activator sensor )对不同次生代谢物的调控具有特异性。     

A genome shuffling-generated <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis> isolate that ferments xylose and glucose to produce high levels of ethanol

Genome shuffling is an efficient approach for the rapid improvement of industrially important microbial phenotypes. This report describes optimized conditions for protoplast preparation, regeneration, inactivation, and fusion using the Saccharomyces cerevisiae W5 strain. Ethanol production was confirmed by TTC (triphenyl tetrazolium chloride) screening and high-performance liquid chromatography (HPLC). A genetically stable, high ethanol-producing strain that fermented xylose and glucose was obtained following three rounds of genome shuffling. After fermentation for 84 h, the high ethanol-producing S. cerevisiae GS3-10 strain (which utilized 69.48 and 100% of the xylose and glucose stores, respectively) produced 26.65 g/L ethanol, i.e., 47.08% higher than ethanol production by S. cerevisiae W5 (18.12 g/L). The utilization ratios of xylose and glucose were 69.48 and 100%, compared to 14.83 and 100% for W5, respectively. The ethanol yield was 0.40 g/g (ethanol/consumed glucose and xylose), i.e., 17.65% higher than the yield by S. cerevisiae W5 (0.34 g/g).     

人诱导多能干细胞与人胚胎干细胞分化过程中Oct4/Nanog 基因 表达的比较

目的:比较通过慢病毒方法获得的人诱导多能性干细胞(iPSCs)与人胚胎干细胞(hESCs)分化过程中全能性基因Oct4、Nanog的表达变化。方法:收集分化不同时间点的拟胚体(EBs),检测三胚层分化基因以及全能性基因Oct4/Nanog的表达,并通过畸胎瘤组织切片的荧光染色分析Oct4的表达。结果:iPSCs获得的EB中内外三胚层分化基因表达的出现明显晚于hESCs来源的EB。不同于hESCs,iPSCs悬浮培养获得的EBs在体外培养18天未见内源性Oct4、Nanog基因表达的下调。未分化的iPSCs注射严重联合免疫缺陷(SCID)小鼠培养10周后获得的畸胎瘤中仍存在Oct4阳性的细胞,但iPS-#2中明显少于iPS-#5。结论:通过慢病毒方法获得的iPSCs虽然具有向三胚层分化的能力,但在分化过程中仍维持较高水平的全能性基因Oct4、Nanog的表达。     

Prolonged renal allograft survival by donor interleukin-6 deficiency: association with decreased alloantibodies and increased intragraft T regulatory cells

Both humoral and cellular immune responses are involved in renal allograft rejection. Interleukin (IL)-6 is a regulatory cytokine for both B and Foxp3 (forkhead box P3)-expressing regulatory T (Treg) cells. This study was designed to investigate the impact of donor IL-6 production on renal allograft survival. Donor kidneys from IL-6 knockout (KO) vs. wild-type (WT) C57BL/6 mice (H-2(b)) were orthotopically transplanted to nephrotomized BALB/c mice (H-2(d)). Alloantibodies and Treg cells were examined by fluorescence-activated cell sorting analysis. Graft survival was determined by the time to graft failure. Here, we showed that a deficiency in IL-6 expression in donor kidneys significantly prolonged renal allograft survival compared with WT controls. IL-6 protein was upregulated in renal tubules and endothelium of renal allografts following rejection, which correlated with an increase in serum IL-6 compared with that in those receiving KO grafts or naive controls. The absence of graft-producing IL-6 or lower levels of serum IL-6 in the recipients receiving IL-6 KO allografts was associated with decreased circulating anti-graft alloantibodies and increased the percentage of intragraft CD4(+)CD25(+)Foxp3(+) Treg cells compared with those with WT allografts. In conclusion, the lack of graft-producing IL-6 significantly prolongs renal allograft survival, which is associated with reduced alloantibody production and/or increased intragraft Treg cell population, implying that targeting donor IL-6 may effectively prevent both humoral and cellular rejection of kidney transplants.     

LEF-1表达与肿瘤进程研究进展

淋巴增强因子-1(lymphoid enhancer factor-1,LEF-1)属于高迁移组分(HMG)家族,它与TCRα的增强子相互作用形成特定的构象,从而与其它因子结合共同调节基因的表达。LEF-1作为核内的转录因子介导Wnt信号通路,对细胞的增殖、分化和凋亡起重要作用。近年来,研究显示许多肿瘤的发生与Wnt信号通路的异常有关,而LEF-1在肿瘤的发生发展侵润过程中起重要作用。同时,LEF-1是一个多启动子基因,编码产生致瘤的全长形式的LEF-1和对Wnt信号通路起负向调控作用的截短形式的LEF-1。研究结果表明,肿瘤的发生发展与LEF/TCF各亚型的比例有关。因此,研究LEF-1的结构、功能以及其在细胞增殖、细胞存活、肿瘤的发生发展过程中的作用意义重大。该文就LEF-1的表达以及与肿瘤的关系作一综述。     

Genetic Heterogeneity of the β-Globin Gene in Various Geographic Populations of Yunnan in Southwestern China

Objectives

The aim of this study was to investigate the geographic distribution of β-globin gene mutations in different ethnic groups in Yunnan province.

Methods

From 2004 to 2014, 1,441 subjects with hemoglobin disorders, identified by PCR-reverse dot blot and DNA sequencing, were studied according to ethnicity and geographic origin. Haplotypes were examined among 41 unrelated thalassemia chromosomes.

Results

Eighteen β-thalassemia mutations and seven hemoglobin variants were identified for 1,616 alleles in 22 different ethnic groups from all 16 prefecture-level divisions of Yunnan. The prevalence of β-thalassemia was heterogeneous and regionally specific. CD 41-42 (-TCTT) was the most prevalent mutation in the populations of northeastern Yunnan. CD 17 (A>T) was the most common mutation in the populations of southeastern Yunnan, especially for the Zhuang minority, whereas Hb E (CD 26, G>A) was the most prevalent mutation in populations of southwestern Yunnan, especially for the Dai minority. Among the seven types of haplotypes identified, CD 17 (A>T) was mainly linked to haplotype VII (+ - - - - - +) and IVS-II-654 (C>T) was only linked to haplotype I (+ - - - - + +).

Conclusion

Our data underline the heterogeneity of β-globin gene mutations in Yunnan. This distribution of β-globin mutations in the geographic regions and ethnic populations provided a detailed ethnic basis and evolutionary view of humans in southern China, which will be beneficial for genetic counseling and prevention strategies.