A dual functional fluorescent probe for glioma imaging mediated by Blood-brain barrier penetration and glioma cell targeting

Glioma is a huge threat for human being because it was hard to be completely removed owing to both the infiltrating growth of glioma cells and integrity of blood brain barrier. Thus effectively imaging the glioma cells may pave a way for surgical removing of glioma. In this study, a fluorescent probe, Cy3, was anchored onto the terminal of AS1411, a glioma cell targeting aptamer, and then TGN, a BBB targeting peptide, was conjugated with Cy3-AS1411 through a PEG linker. The production, named AsT, was characterized by gel electrophoresis, ¹H NMR and FTIR. In vitro cellular uptake and glioma spheroid uptake demonstrated the AsT could not only be uptaken by both glioma and endothelial cells, but also penetrate through endothelial cell monolayer and uptake by glioma spheroids. In vivo, AsT could effectively target to glioma with high intensity. In conclusion, AsT could be used as an effective glioma imaging probe.     

Characterization of Protein Flexibility Using Small-Angle X-Ray Scattering and Amplified Collective Motion Simulations

Large-scale flexibility within a multidomain protein often plays an important role in its biological function. Despite its inherent low resolution, small-angle x-ray scattering (SAXS) is well suited to investigate protein flexibility and determine, with the help of computational modeling, what kinds of protein conformations would coexist in solution. In this article, we develop a tool that combines SAXS data with a previously developed sampling technique called amplified collective motions (ACM) to elucidate structures of highly dynamic multidomain proteins in solution. We demonstrate the use of this tool in two proteins, bacteriophage T4 lysozyme and tandem WW domains of the formin-binding protein 21. The ACM simulations can sample the conformational space of proteins much more extensively than standard molecular dynamics (MD) simulations. Therefore, conformations generated by ACM are significantly better at reproducing the SAXS data than are those from MD simulations.     

Streptococcus mutans Extracellular DNA Is Upregulated during Growth in Biofilms,Actively Released via Membrane Vesicles,and Influenced by Components of the Protein Secretion Machinery

Streptococcus mutans, a major etiological agent of human dental caries, lives primarily on the tooth surface in biofilms. Limited information is available concerning the extracellular DNA (eDNA) as a scaffolding matrix in S. mutans biofilms. This study demonstrates that S. mutans produces eDNA by multiple avenues, including lysis-independent membrane vesicles. Unlike eDNAs from cell lysis that were abundant and mainly concentrated around broken cells or cell debris with floating open ends, eDNAs produced via the lysis-independent pathway appeared scattered but in a structured network under scanning electron microscopy. Compared to eDNA production of planktonic cultures, eDNA production in 5- and 24-h biofilms was increased by >3- and >1.6-fold, respectively. The addition of DNase I to growth medium significantly reduced biofilm formation. In an in vitro adherence assay, added chromosomal DNA alone had a limited effect on S. mutans adherence to saliva-coated hydroxylapatite beads, but in conjunction with glucans synthesized using purified glucosyltransferase B, the adherence was significantly enhanced. Deletion of sortase A, the transpeptidase that covalently couples multiple surface-associated proteins to the cell wall peptidoglycan, significantly reduced eDNA in both planktonic and biofilm cultures. Sortase A deficiency did not have a significant effect on membrane vesicle production; however, the protein profile of the mutant membrane vesicles was significantly altered, including reduction of adhesin P1 and glucan-binding proteins B and C. Relative to the wild type, deficiency of protein secretion and membrane protein insertion machinery components, including Ffh, YidC1, and YidC2, also caused significant reductions in eDNA.     

Tanshinone biosynthesis in Salvia miltiorrhiza and production in plant tissue cultures

Salvia miltiorrhiza Bunge (Lamiaceae) root, generally called Danshen, is an important herb in Chinese medicine widely used for treatment of cardiovascular diseases. Diterpenoid tanshinons are major bioactive constituents of Danshen with notable pharmacological activities and the potential as new drug candidates against some important human diseases. The importance of Danshen for traditional and modern medicines has motivated the research interest over two decades in the biosynthesis and biotechnological production of tanshinones. Although diterpenes in plants are presumably derived from the non-mevalonate (MVA) pathway, tanshinone biosynthesis in S. miltiorrhiza may also depend on the MVA pathway based on some key enzymes and genes detected in the early steps of these pathways. Plant tissue cultures are the major biotechnological processes for rapid production of tanshinones and other bioactive compounds in the herb. Various in vitro cultures of S. miltiorrhiza have been established, including cell suspension, adventitious root, and hairy root cultures, which can accumulate the major tanshinones as in the plant roots. Tanshinone production in cell and hairy root cultures has been dramatically enhanced with various strategies, including medium optimization, elicitor stimulation, and nutrient feeding operations. This review will summarize the above developments and also provide our views on future trends.     

Inhibition of human lung adenocarcinoma growth using survivint34a by low-dose systematic administration

Anti-apoptosis plays an important role in tumour formation and development. Survivin is a member of the inhibitor of apoptosis (IAP) family, which is a target for anti-cancer drug exploitation was replaced as development. We investigated the role of the homo dominant-negative mutant Survivin-T34A in suppressing human lung adenocarcinomas (A549). The anti-tumour activity of HSurvivinT34A plasmid was evaluated in the A549 cell line and nude mice bearing A549 subcutaneous tumours. Low-dose systemic administration was continuously used. The HSurvivinT34A plasmid (5 µg/one) complexed with a cationic liposome (DOTAP/Chol) significantly inhibited tumour growth in our model. We observed microvessel density degradation by CD31 immunohistochemistry and apoptotic cell increase by TUNEL assay, PI staining and flow cytometric analysis in the treated group. The present findings suggest that the HSurvivinT34A plasmid complexed with a cationic liposome may provide an effective approach to inhibit the growth of human lung adenocarcinomas in vitro and in vivo.     

云南傣族、汉族HLA-G基因14bp插入/缺失多态性研究

14bp插入/缺失多态性是指存在于HLA-G基因第8外显子3′非翻译区(3′UTR)的一个插入/缺失多态,因其能影响HLA-GmRNA的稳定性,并进一步影响HLA-G蛋白的翻译而受到广泛关注。文章采用PCR和电泳技术对云南傣族和汉族两个人群进行了HLA-G基因14bp插入/缺失多态性的检测分析,结果显示傣族和汉族人群+14bp等位基因频率分别为31.97%和40.87%,+14bp/+14bp基因型频率分别为8.20%和17.31%,+14bp/-14bp基因型频率分别为47.54%和47.11%。与国内外已报道的其他人群的数据比较表明:云南汉族群体中HLA-G基因14bp插入/缺失的分布与其他群体相似;傣族则有自己独特的基因型和等位基因分布特点,推测其可能受到了遗传漂变的作用,但不排除自然选择作用的影响。     

西藏小昌都黑白仰鼻猴的雄婴照料:能量胁迫导致?

雄猴照料婴猴行为通常都是从雄猴的角度来分析该行为具有何种适应功能,很少有研究关心为什么雌猴会让雄猴参与照料活动。该文通过西藏小昌都黑白仰鼻猴群的系统观察取样,采用回归分析雄婴照料行为季节变动与婴猴年龄及生态因子（环境温度、食物供应）之间的关系,试图分析是否由于能量胁迫导致雌猴让雄猴参与照料活动,并通过分析高能量胁迫季节（环境温度低、食物缺乏,婴猴年幼需要雌猴携带多）与低能量胁迫季节（环境温度高、食物丰富,婴猴年长需要雌猴携带少）雄婴照料行为差异检验了能量胁迫假说。结果表明雄婴照料行为与温度呈负相关函数,而雌猴照料婴猴行为与温度呈正相关函数;在高能量胁迫的季节,雄猴参与照料行为多,而在低能量胁迫的季节雄猴照料行为少。因此,作者认为是能量胁迫迫使雌猴放弃部分照料婴猴的机会,雄猴利用照料机会获得了其他利益。     

Splicing‐dependent NMD does not require the EJC in Schizosaccharomyces pombe

Nonsense‐mediated mRNA decay (NMD) is a translation‐linked process that destroys mRNAs with premature translation termination codons (PTCs). In mammalian cells, NMD is also linked to pre‐mRNA splicing, usually PTCs trigger strong NMD only when positioned upstream of at least one intron. The exon junction complex (EJC) is believed to mediate the link between splicing and NMD in these systems. Here, we report that in Schizosaccharomyces pombe splicing also enhances NMD, but against the EJC model prediction, an intron stimulated NMD regardless of whether it is positioned upstream or downstream of the PTC and EJC components are not required. Still the effect of splicing seems to be direct—we have found that the important NMD determinant is the proximity of an intron to the PTC, not just the occurrence of splicing. On the basis of these results, we propose a new model to explain how splicing could affect NMD.