哺乳动物合成生物学在生物医学领域的研究进展

虽然合成生物学还处于早期研究阶段,但最近十年,该领域取得了非常显著的研究进展。合成生物学是以工程学思想为基础,通过人工设计、改造基因线路,从而赋予细胞或生物体新的功能,现已广泛应用于各个领域。随着人们对基因线路设计的深入研究,使得合成生物学研究走向临床应用成为可能。本文将围绕哺乳动物合成生物学在疾病治疗方面的研究进展,介绍基因线路的设计思路和方法、不同诱导因子调控的开环式基因线路以及用于疾病诊疗的闭环式基因环路在生物医学领域的应用。最后对合成生物学走向临床治疗的应用前景和挑战进行展望。     

Cyst‐motile stage relationship and molecular phylogeny of a new freshwater dinoflagellate Gymnodinium plasticum from Plastic Lake,Canada

The dinophyceaen genus Gymnodinium was established with the freshwater species G. fuscum as type. According to Thessen et al. (2012), there are 268 species, with the majority marine species. In recently published molecular phylogenies based on ribosomal DNA sequences, Gymnodinium is polyphyletic. Here, a new freshwater Gymnodinium species, G. plasticum, is described from Plastic Lake, Ontario, Canada. Two strains were established by incubating single cysts, and their morphology was examined with light microscopy and scanning electron microscopy. The cyst had a rounded epicyst and hypocyst with a wide cingulum and smooth surface. Vegetative cells were characterized by an elongated nucleus running vertically and a deep sulcal intrusion. The apical structure complex was horseshoe‐shaped and consisted of two pronounced ridges with a deep internal groove, encircling 80% of the apex. Small subunit ribosomal DNA (SSU rDNA), large subunit ribosomal DNA (LSU rDNA) and internal transcribed spacer (ITS) sequences were obtained from cultured strains. Molecular phylogeny based on concatenated SSU, LSU and ITS sequences supports the monophyly of the Gymnodiniales sensu stricto clade but our results suggest that many Gymnodinium species might need reclassification. Gymnodinium plasticum is closest to Dissodinium pseudolunula in our phylogeny but distant from the type species G. fuscum, as are the other gymnodiniacean taxa.     

Quantitative real‐time PCR detection of a harmful unarmoured dinoflagellate,Karlodinium australe (Dinophyceae)

We investigated a harmful algal bloom (HAB) associated with the massive fish kills in Johor Strait, Malaysia, which recurred a year after the first incident in 2014. This incident has urged for the need to have a rapid and precise method in HAB monitoring. In this study, we develop a SYBR green‐based real‐time PCR (qPCR) to detect the culpable dinoflagellate species, Karlodinium australe. Species‐specific qPCR primers were designed in the gene region of the second internal transcribed spacer of the ribosomal RNA gene (rDNA). The species specificity of the primers designed was evaluated by screening on the non‐target species (Karlodinium veneficum, Takayama spp., and Karenia spp.) and no cross‐detection was observed. The extractable gene copies per cell of K. australe determined in this study were 19 998 ± 505 (P < 0.0001). Estimation of cell densities by qPCR in the experimental spiked samples showed high correlation with data determined microscopically (R² = 0.93). Using the qPCR assay developed in this study, we successfully detected the 2015 bloom species as K. australe. Single‐cell PCR and rDNA sequencing from the field samples further confirmed the finding. With the sensitivity as low as five cells, the qPCR assay developed in this study could effectively and rapidly detect cells of K. australe in the environmental samples for monitoring purpose.     

The molecular mechanism underlying anthocyanin metabolism in apple using the MdMYB16 and MdbHLH33 genes

Key message

MdMYB16 forms homodimers and directly inhibits anthocyanin synthesis via its C-terminal EAR repressor. It weakened the inhibitory effect of MdMYB16 on anthocyanin synthesis when overexpressing MdbHLH33 in callus overexpressing MdMYB16. MdMYB16 could interact with MdbHLH33.

Abstract

Anthocyanins are strong antioxidants that play a key role in the prevention of cardiovascular disease, cancer, and diabetes. The germplasm of Malus sieversii f. neidzwetzkyana is important for the study of anthocyanin metabolism. To date, only limited studies have examined the negative regulatory mechanisms underlying anthocyanin synthesis in apple. Here, we analyzed the relationship between anthocyanin levels and MdMYB16 expression in mature Red Crisp 1–5 apple (M. domestica) fruit, generated an evolutionary tree, and identified an EAR suppression sequence and a bHLH binding motif of the MdMYB16 protein using protein sequence analyses. Overexpression of MdMYB16 or MdMYB16 without bHLH binding sequence (LBSMdMYB16) in red-fleshed callus inhibited MdUFGT and MdANS expression and anthocyanin synthesis. However, overexpression of MdMYB16 without the EAR sequence (LESMdMYB16) in red-fleshed callus had no inhibitory effect on anthocyanin. The yeast one-hybrid assay showed that MdMYB16 and LESMdMYB16 interacted the promoters of MdANS and MdUFGT, respectively. Yeast two-hybrid, pull-down, and bimolecular fluorescence complementation assays showed that MdMYB16 formed homodimers and interacted with MdbHLH33, however, the LBSMdMYB16 could not interact with MdbHLH33. We overexpressed MdbHLH33 in callus overexpressing MdMYB16 and found that it weakened the inhibitory effect of MdMYB16 on anthocyanin synthesis. Together, these results suggested that MdMYB16 and MdbHLH33 may be important part of the regulatory network controlling the anthocyanin biosynthetic pathway.

     

小兴安岭红松径向生长对未来气候变化的响应

基于SRES A1B温室气体排放情景,由全球气候模式(MPI_ECHAM5)产生的逐日气候模拟数据驱动TREE-RING树轮生态机理模型,模拟了小兴安岭红松(Pinus koraiensis)树木径向生长变化.结果表明:在A1B情景下,随着大气CO2浓度的不断增加以及局地气温的不断升高,红松树木生长开始和结束时间显著提前,2011-2060年比1961-2010年径向生长开始时间平均提前约5d左右,生长结束时间平均提前约3d左右.红松树木的径向生长量不断增加,2011-2060年比1961 -2010年径向生长量平均增加约35％,径向生长量的增加主要是CO2施肥作用的结果,在不考虑CO2施肥效应下,只考虑降水量变化使树木径向生长量增加约2％,而未来50a的气温变化使树木径向生长量相对于1961 -2010年减少约23％.     

生物反应器及其研究技术进展

阐述了生物反应器设计、放大的新理念及关键技术发展,并在此基础上综述了应用于生物技术产品生产的生物反应器的主要发展趋势,包括以代谢流分析为核心的生物反应器系统、基于计算流体力学模拟技术的传统发酵罐改良、微型生物反应器、动物细胞反应器和酶反应器。     

黄河口盐地碱蓬湿地土壤-植物系统重金属污染评价

以黄河口盐地碱蓬湿地为例,评价了淹水和非淹水区湿地表层土壤As、Cd、Cu、Cr、Pb和Zn 6种重金属的污染程度及其在土壤-植物系统中的迁移、富集特征,分析了不同积水深度和土壤理化性质对研究区土壤重金属含量的影响.研究结果表明,与土壤或沉积物质量标准相比,黄河口盐地碱蓬湿地土壤受As和Cd污染最严重,而其它重金属污染较轻;非淹水土壤Cd、Cr和Zn含量高于淹水湿地,而As、Cu和Pb则较低;而且淹水土壤As含量随积水深度增加而呈下降趋势,但积水深度对其他重金属含量的影响不明显.相关性分析结果表明,按照受土壤关键影响因子的不同重金属(除As外)可以分为两类:第一类为Cd、Cr和Zn,这些重金属含量受土壤pH值和盐分影响较大,且相互间存在显著正相关关系,表明它们可能有相同的来源;第二类为Pb和Cu,它们受土壤pH值、盐分和有机质的影响,且Pb和Cu之间存在显著正相关关系.除Cr、Cu和Zn外,重金属在盐地碱蓬的根系内一般不发生显著富集,但绝大多数重金属都表现出地上部分的含量比根系更高的现象.     

发状念珠藻胞外多糖的纯化与性质分析

采用DEAE阴离子交换层析和Sephadex G100凝胶层析对液体悬浮培养发状念珠藻胞外多糖进行纯化, 得到两个组分NFPS1和NFPS2。对组分NFPS2进行理化性质分析, 并与野生发状念珠藻多糖NFPS0的性质进行对比。结果表明二者具有相似的单糖组成, 均为葡萄糖、木糖、半乳糖、甘露糖; 表观分子量分别为2.79×105、2.26×105; 均不含核酸、蛋白质等物质, 是非硫酸化多糖; 有较高的热稳定性, 其降解温度在245oC左右。但在微观结构上, 两者存在一定差别。     

感光性的遗传背景对水稻短光诱导雄性不育特性表达的影响研究

通过对双亲及Ｆ１的感光性分析和Ｆ２群体单株的感光性及短光不育特性分析表明,强感光性对弱感光性表现为显性;具短光不育特性的单株其感光性均表现为中度以上感光（短日出穗促进率〉１５％）。对宜ＤＩＳ与宜Ｄ２Ｓ的光敏性、感光性分析和不育基因的等位性测定表明,两者感光性与光敏性符合正相关的结论,它们的不育主基因是等位的。可以认为,对短光低温不育水稻,短光不育基因需要在感光性基因存在时才能得到表达,同一不育基因