Implication of RNA-binding protein La in proliferation, migration and invasion of lymph node-metastasized hypopharyngeal SCC cells

The 5-year survival rate for oral cavity cancer is poorer than for breast, colon or prostate cancer, and has improved only slightly in the last three decades. Hence, new therapeutic strategies are urgently needed. Here we demonstrate by tissue micro array analysis for the first time that RNA-binding protein La is significantly overexpressed in oral squamous cell carcinoma (SCC). Within this study we therefore addressed the question whether siRNA-mediated depletion of the La protein may interfere with known tumor-promoting characteristics of head and neck SCC cells. Our studies demonstrate that the La protein promotes cell proliferation, migration and invasion of lymph node-metastasized hypopharyngeal SCC cells. We also reveal that La is required for the expression of β-catenin as well as matrix metalloproteinase type 2 (MMP-2) within these cells. Taken together these data suggest a so far unknown function of the RNA-binding protein La in promoting tumor progression of head and neck SCC.     

Lentivirus‐mediated bifunctional cell labeling for in vivo melanoma study

Lentiviral vectors (LVs) are capable of labeling a broad spectrum of cell types, achieving stable expression of transgenes. However, for in vivo studies, the duration of marker gene expression has been highly variable. We have developed a series of LVs harboring different promoters for expressing reporter gene in mouse cells. Long‐term culture and colony formation of several LV‐labeled mouse melanoma cells showed that promoters derived from mammalian house‐keeping genes, especially those encoding RNA polymerase II (Pol2) and ferritin (FerH), provided the highest consistency for reporter expression. For in vivo studies, primary B16BL6 mouse melanoma were infected with LVs whose luciferase–green fluorescence protein fusion gene (Luc/GFP) was driven by either Pol2 or FerH promoters. When transplanted into syngeneic C57BL/6 mice, Luc/GFP‐labeled B16BL6 mouse melanoma cells can be monitored by bioluminescence imaging in vivo, and GFP‐positive cells can be isolated from the tumors by fluorescence‐activated cell sorter. Pol2‐Luc/GFP labeling, while lower in activity, was more sustainable than FerH‐Luc/GFP labeling in B16BL6 over consecutive passages into mice. We conclude that Pol‐2‐Luc/GFP labeling allows long‐term in vivo monitoring and tumor cell isolation in immunocompetent mouse melanoma models.     

The effect of ultrasonication on the immunomodulatory activity of low‐quality ginseng

This study investigated the effects of ultrasonication extraction (UE) on the immunomodulatory activity of low‐quality ginseng. The results indicate that the optimal conditions for extracting low‐quality ginseng are ultrasonication at 60 kHz and 85°C for 60 min. The extraction yield from the UE was 20% higher than that of the water extraction (WE) at 100°C. The low quality ginseng obtained from the UE exhibited relatively low cytotoxicity toward normal human cells, with an observed toxicity of 15–18% at a concentration of 1.0 mg/mL. The ginseng product obtained following UE induced human B and T cells growth and resulted in concentrations of up to 9.33 × 10⁴ cells/mL and 15.33 × 10⁴ cells/mL, respectively. The ginseng extract also increased the secretion of interleukin‐6 and tumor necrosis factor‐α from these cells by up to 35%, and natural killer/ cell growth was also improved by up to 30%. The UE effectively released 2‐ to 3‐fold higher levels of ginsenosides than the WE. Specifically, the obtained levels of Rb₁, Re, and Rg₁, which are likely immunomodulatory factors, were approximately three times higher after ultrasonication than after WE. These results were further supported by the finding that UE product‐treated macrophages produced higher levels of nitric oxide (21 μM) than macrophages treated with the WE product or with standard ginsenosides. These results demonstrate that this optimized ultrasonication process effectively destroyed the more rigid cell walls of low‐quality ginseng and released high levels of ginsenosides. This work is the first to correlate extraction parameters with both extraction yields and biological activity. The use of low‐quality ginseng can thus be expanded by utilizing a low‐temperature ultrasonic extraction process. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013     

利用合成气生产生物基醇类化学品的研究进展

以合成气为底物生产乙醇、丁醇、己醇等生物基醇类化学品可以降低原料成本,减轻对化石燃料的依赖,推动碳中和目标的实现。概述了产乙酸菌中能够利用合成气的Wood-Ljungdahl途径及该过程中产乙酸菌的能量节约机制,综述了产乙酸菌遗传操作工具的发展及代谢工程改造进展。大量研究揭示了发酵条件（如温度、pH、金属离子、有机氮源、硝酸盐等）对产乙酸菌生长及醇类产物合成具有复杂的影响。气体成分及气液传质效率也是影响合成气利用的重要因素。另外,指出了利用合成气生产生物基醇类化学品现存的瓶颈问题,并展望了未来的研究方向,包括开发产乙酸中的高效基因编辑方法,在模式菌株中构建合成气利用途径、优化温度、pH、反应器设计及利用廉价培养基进行发酵。     

斑叶海棠薄层培养中细胞无丝分裂及2,4—D的特殊效应的研究

以经过预培养的斑叶海棠为材料,取叶柄表层3—4层细胞,切成8×10mm大小作为外植体,所用培养基采用MS基本成份附加不伺浓度的2,4-D。结果如下:1.在含0.1mg/l 2,4-D的培养基上,大多数叶柄表皮细胞可以进行一次无丝分裂。与有丝分裂一样,无丝分裂中有核仁和核膜的消失和再现。分裂过程中核始终靠近细胞壁,细胞分隔部分的伸展也是单向的。2.实验中2,4-D对表皮细胞产生了很特殊的效应。在0.1mg/l 2,4-D的培养基上培养45小时后,细胞都发生收缩。收缩以前大多数细胞都有过一次无丝分裂。如果2,4—D的浓度降至0.01mg/l,细胞将反复进行无丝分裂形成疏松的愈伤组织而不发生收缩。     

Simultaneous determination of catecholamines in rat brain tissue by high-performance liquid chromatography

A novel and highly sensitive method has been developed for the determination of catecholamines [noradrenaline (NA), dopamine (DA), serotonin (5-HT) and their metabolites 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA)] in brain tissue. The method uses isocratic reversed-phase HPLC with amperometric end-point detection. The calibration curve was linear over the range 10–150 pg on-column. The assay limits of detection for NA, DA, 5-HT, 5-HIAA and HVA were 3.8, 3.8, 6.8, 5 and 7.5 pg on-column, respectively. The mean inter- and intra-assay relative standard deviations (RSDs) over the range of the standard curve were less than 5%. The absolute recoveries averaged 99.1%, 99.5%, 97.7%, 99.5% and 98.8% for NA, DA, 5-HT, 5-HIAA and HVA, respectively.     

Measurement of hyperforin a constituent of St. John’s wort in plasma by high-performance liquid chromatography

Hyperforin is a constituent of Hypericum perforatum extracts (St. John’s wort, H. perforatum), which have antidepressant action. Hyperforin was extracted from plasma utilising a solid-phase extraction procedure. Chromatography was performed by isocratic reversed-phase high-performance liquid chromatography with UV end-point detection. The calibration curve was linear over the range 0.15–3 μg per ml of plasma. The sensitivity for hyperforin was 4.5 ng on-column. Mean inter- and intra-assay relative standard deviations over the range of the standard curve were less than 5%. The absolute recovery for hyperforin averaged 97.8%.     

提高小麦基因枪法转化频率的研究

用基因枪法将带Ｂａｒ－ＧＵＳ双标记基因的质粒较入普通春小麦品种中－６０６３４的幼胚盾片,并获基因植株。在轰击的经预培养３－４天的３４２块幼胚片再经筛选再生的植株中,经ＰＣＲ和Ｓｏｕｔｈｅｒｎ分析表明,     

c-Myc Overexpression Uncouples DNA Replication from Mitosis

c-myc has been shown to regulate G(1)/S transition, but a role for c-myc in other phases of the cell cycle has not been identified. Exposure of cells to colcemid activates the mitotic spindle checkpoint and arrests cells transiently in metaphase. After prolonged colcemid exposure, the cells withdraw from mitosis and enter a G(1)-like state. In contrast to cells in G(1), colcemid-arrested cells have decreased G(1) cyclin-dependent kinase activity and show hypophosphorylation of the retinoblastoma protein. We have found that overexpression of c-myc causes colcemid-treated human and rodent cells to become either apoptotic or polyploid by replicating DNA without chromosomal segregation. Although c-myc-induced polyploidy is not inhibited by wild-type p53 in immortalized murine fibroblasts, overexpression of c-myc in primary fibroblasts resulted in massive apoptosis of colcemid-treated cells. We surmise that additional genes are altered in immortalized cells to suppress the apoptotic pathway and allow c-myc-overexpressing cells to progress forward in the presence of colcemid. Our results also suggest that c-myc induces DNA rereplication in this G(1)-like state by activating CDK2 activity. These observations indicate that activation of c-myc may contribute to the genomic instability commonly found in human cancers.