Bioleaching of chalcopyrite concentrate by a moderately thermophilic culture in a stirred tank reactor

A mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainage samples collected from several chalcopyrite mines in China. Such mixed culture can be used to effectively extract copper from chalcopyrite. Furthermore, after being adapted to gradually increased concentration of chalcopyrite concentrate, the tolerance of the mixed culture to chalcopyrite concentrate was brought up to 80 g/L. The effects of several leaching parameters on copper recovery in stirred tank reactor also had been investigated. The results of the investigation show that it was possible to achieve a copper extraction rate of 75% in 44 days at a pulp density of 8%. The leaching rate of chalcopyrite concentrate tended to increase with dissolved total iron concentration. At low pH ranges, more microscopic counts of microorganisms were found in the solution. Furthermore, the analysis of leached residues indicates that the passivation of chalcopyrite concentrate was mainly due to a mass of jarosite and PbSO(4) on the mineral surface, other than the elemental sulphur layer. The bacterial community composition was analyzed by using Amplified Ribosomal DNA Restriction Analysis. Two moderately thermophilic bacteria species were identified as Leptospirillum ferriphilum and Acidithiobacillus caldus with abundance of 67% and 33% in the bio-pulp, respectively.     

Study of two-stage processes for the microbial production of 1,3-propanediol from glucose

The microbial production of 1,3-propanediol (1,3-PD) from glucose was studied in a two-stage fermentation process on a laboratory scale. In the first stage, glucose was converted to glycerol either by the osmotolerant yeast Pichia farinosa or by a recombinant Escherichia coli strain. In the second stage, glycerol in the broth from the first stage was converted to 1,3-PD by Klebsiella pneumoniae. The culture broth from P. farinosa was shown to contain toxic metabolites that strongly impair the growth of K. pneumoniae and the formation of 1,3-PD. Recombinant E. coli is more suitable than P. farinosa for producing glycerol in the first stage. The fermentation pattern from glycerol can be significantly altered by the presence of acetate, leading to a significant reduction of PD yield in the second stage. However, in the recombinant E. coli culture acetate formation can be prevented by fed-batch cultivation under limiting glucose supply, resulting in an effective production of 1,3-PD in the second stage with a productivity of 2.0 g l(-1) h(-1) and a high yield (0.53 g/g) close to that of glycerol fermentation in a synthetic medium. The overall 1,3-PD yield from glucose in the two stage-process with E. coli and K. pneumoniae reached 0.17 g/g.     

簇毛麦端体6VS的显微切割及其专化DNA序列的克隆和分析

从簇毛麦(Haynaldia villosa (L.) Schur.)组合CA9211/RW15(6D/6V异代换系)幼胚培养SC2后代中,用原位杂交方法鉴定出T240-6为6VS端体异代换系. 以此为材料,采用微细玻璃针切割法及"单管反应"技术体系,对6VS进行切割分离及LA (Linker adaptor)-PCR扩增.扩增带在100～3 000 bp 之间,大部分集中在600～1 500 bp.利用32P标记的簇毛麦基因组为探针进行Southern杂交,证实扩增产物来源于簇毛麦.扩增产物纯化后,连接到pGEM-T载体上,构建了6VS DNA质粒文库.对文库的分析表明,文库大约有17 000个白色克隆;插入片段分布在100～1 500 bp,平均600 bp.点杂交结果表明,37%克隆有中度到强烈的杂交信号,证明含有中度或高度重复序列;63%克隆有较弱的信号或没有信号,证明为单/低拷贝序列克隆.从文库中获得8个簇毛麦特异克隆,对其中两个克隆pHVMK22和 pHVMK134进行了RFLP分析和序列分析,并利用该探针对小麦抗白粉病基因Pm21进行了检测.RFLP 结果表明,两个克隆一个为低拷贝序列克隆(pHVMK22),另一个为高度重复序列克隆,均为簇毛麦专化DNA序列.以pHVMK22为探针对抗、感病小麦(Triticum aestivum L.)品系的Southern杂交发现抗病品系有一条2 kb的特征带, 该探针可能作为检测抗病基因Pm21的探针.     

推进组织学与胚胎学双语教学培养高素质医学人材——双语教学改革阶段性成果简介

经过两年多的组织学与胚胎学双语教学改革,我们在双语教学大纲编写、课程设置、教材建设、教学工作安排和学生考试等方面,已取得了阶段性的成果,达到了学校批准立项的教学改革专项（双语课程建设）研究课题预期目标,为我们进一步完善组织学与胚胎学双语教学改革打下了坚实的基础。     

Stereoselective Accumulation of Propranolol Enantiomers in K562 and K562/ADR Cells

The stereoselective uptake of propranolol enantiomers was investigated by using the K562 and K562 adriamycin‐resistant cell line (K562/ADR) as a model. An enantioselective RP‐HPLC method was applied to determine the accumulation of propranolol (PPL) stereoisomers in K562 and K562/ADR cells. The concentration, time and temperature dependent studies showed that the accumulation of S‐(?)‐PPL was higher than R‐(+)‐PPL in K562 cells and uptake of R‐(+)‐PPL was significantly higher than that of S‐(?)‐PPL in K562/ADR cells. The results indicate the enantioselective accumulation of propranolol enantiomers in K562 and K562 / ADR cells. Chirality 25:361–364, 2013. © 2013 Wiley Periodicals, Inc.     

药物筛选生物技术与抗细胞凋亡PI3K信号传导路径

细胞信号传导PI3K-Akt路径涉及细胞周期、再生、分化、衰老与凋亡的调控,采用高通量生物技术分析基因表达谱可用于抗肿瘤或抗衰老的基因与药物筛选.化学诱变剂甲磺酸乙酯(ethlmethane sulformate, EMS)处理CHO细胞,筛选到抗10 μM、20 μM浓度lovastatin的E10、E20突变细胞系,将E10细胞再经诱变剂EMS处理,筛选到抗70 μM浓度lovastatin的ZE70细胞系.Igf-2刺激基因突变的肌肉萎缩小鼠肌肉细胞系,Western免疫杂交试验结果显示,PI3K-Akt路径的Akt蛋白质磷酸化功能正常.生长因子Igf-2刺激肌肉细胞系C2C12的cDNA基因芯片实验表明,促细胞再生、分化相关的基因表达上调,细胞凋亡相关的基因表达下调.细胞的基因突变,激素、Igf-2等生长因子刺激,往往是肿瘤发生的病因;但是,Igf-2等可用于抗肌肉萎缩疾病,以及抗细胞凋亡与衰老的药物筛选.     

Modified heparin inhibits P-selectin-mediated cell adhesion of human colon carcinoma cells to immobilized platelets under dynamic flow conditions

Accumulating evidence indicates that the formation of tumor cell platelet emboli complexes in the blood stream is a very important step during metastases and that the anti-metastasis effects of heparin are partially due to a blockade of P-selectin on platelets. In this study, heparin and chemically modified heparins were tested as inhibitors of three human colon carcinoma cell lines (COLO320, LS174T, and CW-2) binding to P-selectin, adhering to CHO cells expressing a transfected human P-selectin cDNA, and adhering to surface-anchored platelets expressing P-selectin under static and flow conditions. The aim was to screen for heparin derivatives with high anti-adhesion activity but negligible anticoagulant activity. In this study, four modified heparins with high anti-adhesion activity were identified including RO-heparin, CR-heparin, 2/3ODS-heparin, and N/2/3DS-heparin. NMR analysis proved the reliability of structure of the four modified heparins. Our findings suggested that the 6-O-sulfate group of glucosamine units in heparin is critical for the inhibition of P-selectin-mediated tumor cell adhesion. Heparan sulfate-like proteoglycans on these tumor cell surfaces are implicated in adhesion of the tumor cells to P-selectin. Some chemically modified heparins with low anticoagulant activities, such as 2/3ODS-heparin, may have potential value as therapeutic agents that block P-selectin-mediated cell adhesion and prevent tumor metastasis.     

The Hippo–YAP pathway regulates the proliferation of alveolar epithelial progenitors after acute lung injury

Regeneration of pulmonary epithelial cells plays an important role in the recovery of acute lung injury (ALI), which is defined by pulmonary epithelial cell death. However, the mechanism of the regenerative capacity of alveolar epithelial cells is unknown. Using a lung injury mouse model induced by hemorrhagic shock and lipopolysaccharide, a protein mass spectrometry‐based high‐throughput screening and linage tracing technology to mark alveolar epithelial type 2 cells (AEC2s), we analyzed the mechanism of alveolar epithelial cells proliferation. We demonstrated that the expression of Hippo‐yes‐associated protein 1 (YAP1) key proteins were highly consistent with the regularity of the proliferation of alveolar epithelial type 2 cells after ALI. Furthermore, the results showed that YAP1+ cells in lung tissue after ALI were mainly Sftpc lineage‐labeled AEC2s. An in vitro proliferation assay of AEC2s demonstrated that AEC2 proliferation was significantly inhibited by both YAP1 small interfering RNA and Hippo inhibitor. These findings revealed that YAP functioned as a key regulator to promote AEC2s proliferation, with the Hippo signaling pathway playing a pivotal role in this process.     

Nighttime sap flow of Acacia mangium and its implications for nighttime transpiration and stem water storage

Aims Nighttime sap flow of trees may indicate transpiration and/or recharge of stem water storage at night. This paper deals with the water use of Acacia mangium at night in the hilly lands of subtropical South China. Our primary goal was to reveal and understand the nature of nighttime sap flow and its functional significance.Methods Granier's thermal dissipation method was used to determine the nighttime sap flux of A. mangium. Gas exchange system was used to estimate nighttime leaf transpiration and stomatal conductance of studied trees.Important findings Nighttime sap flow was substantial and showed seasonal variation similar to the patterns of daytime sap flow in A. mangium. Mean nighttime sap flow was higher in the less precipitation year of 2004 (1122.4 mm) than in the more precipitation year of 2005 (1342.5 mm) since more daytime transpiration and low soil water availability in the relatively dry 2004 can be the cause of more nighttime sap flow. Although vapor pressure deficit and air temperature were significantly correlated with nighttime sap flow, they could only explain a small fraction of the variance in nighttime sap flow. The total accumulated water loss (E L) by transpiration of canopy leaves was only ~2.6–8.5% of the total nighttime sap flow (E t) during the nights of July 17–18 and 18–19, 2006. Therefore, it is likely that the nighttime sap flow was mainly used for refilling water in the trunk. The stem diameter at breast height, basal area and sapwood area explained much more variance of nighttime water recharge than environmental factors and other tree form features, such as tree height, stem length below the branch, and canopy size. The contribution of nighttime water recharge to the total transpiration ranged from 14.7 to 30.3% depending on different DBH class and was considerably higher in the dry season compared to the wet season.     

重伞灵芝线粒体基因组在灵芝种间鉴定中的应用

线粒体是“动力工厂”,能够进行氧化代谢实现能量的转化,参与三羧酸循环形成ATP。随着分子生物学和生物信息学技术的发展,担子菌灵芝属中已有几种灵芝的线粒体基因组被相继报道,但尚未有对重伞灵芝线粒体基因组的报道。本研究通过对重伞灵芝YX线粒体基因组进行组装注释,比较分析了与其他灵芝属物种的差异,根据差异序列构建分子标记对重伞灵芝菌株快速鉴定。结果显示重伞灵芝线粒体基因组大小为67 340bp的闭合环形结构,含有15个普通蛋白编码基因,28个tRNA基因,以及rRNA的大小亚基基因。共5个基因含有12个内含子,主要为IB型,部分为ID型,包含LAGLIDADG_1 superfamily、GIY-YIG_Cterm superfamily保守结构域。根据重伞灵芝线粒体cox2基因设计的特异性引物扩增结果显示：4株重伞灵芝的cox2基因片段均可准确扩增,且扩增不出其他灵芝物种的cox2基因片段。基于各灵芝菌株线粒体cox2基因序列构建系统进化树,可以将4株重伞灵芝归在同一分支上,并且同源性为98%,与ITS鉴定结果一致。可见,基于线粒体基因cox2特异性引物可以快速地对重伞灵芝进行鉴定,且只需通过观察扩增条带的有无,无需测序,省时省力。