Musashi2 modulates K562 leukemic cell proliferation and apoptosis involving the MAPK pathway

The RNA-binding protein Musashi2 (Msi2) has been identified as a master regulator within a variety of stem cell populations via the regulation of translational gene expression. A recent study has suggested that Msi2 is strongly expressed in leukemic cells of acute myeloid leukemia patients, and elevated Msi2 is associated with poor prognosis. However, the potential role of Msi2 in leukemogenesis is still not well understood. Here, we investigated the effect of Msi2 knockdown on the biological properties of leukemic cells. High expression of Msi2 was found in K562 and KG-1a leukemic cell lines, and low expression was observed in the U937 cell line. We transduced K562 cells with two independent adenoviral shRNA vectors targeting Msi2 and confirmed knockdown of Msi2 at the mRNA and protein levels. Msi2 silencing inhibited cell growth and caused cell cycle arrest by increasing the expression of p21 and decreasing the expression of cyclin D1 and cdk2. In addition, knockdown of Msi2 promoted cellular apoptosis via the upregulation of Bax and downregulation of Bcl-2 expression. Furthermore, Msi2 knockdown resulted in the inactivation of the ERK/MAPK and p38/MAPK pathways, but no remarkable change in p-AKT was observed. These data provide evidence that Msi2 plays an important role in leukemogenesis involving the MAPK signaling pathway, which indicates that Msi2 may be a novel target for leukemia treatment.     

新疆克拉玛依地区佳木河组若干重要孢粉类型

当前的研究材料获自新疆准噶尔盆地西北部克拉玛依地区百口泉424井的佳木河组,涉及部分孢子类型,计有18属24种,其中1新属3新种。这些孢子类型的概貌与欧洲、北美相近,也有若干澳大利亚的分子,其时代为晚石炭世一早二叠世。     

钙处理对红富士苹果酶促褐变的影响

渗钙处理能够明显保持红富士苹果的硬度,且褐变度明显低于对照,渗钙对酶促褐变的抑制作用是通过影响PPO活性和LOX活性起作用的,果实褐变的早期发动与LOX活性相关密切,后期褐变则主要是PPO起作用。     

领蚊属一新种（双翅目：蚊科）

记述采自云南省腾冲县竹筒积水内领蚊1新种,以采获地命名为腾冲领蚊Heizmannia(Heizmannia）tengchongensis sp.nov.,讨论了新种与近缘种的鉴别特征。模式标本保存于云南省疟疾防治研究所。     

核受体辅活化子PNRC与孤儿核受体SF1相互作用位点的鉴定

为了阐明核受体辅活化子 (proline richnuclearreceptorcoactivatorprotein ,PNRC)在孤儿核受体类固醇生成因子 1(steroidogenicfactor1,SF1)基因表达调控中的作用 ,采用酵母双杂合分析、缺失突变技术和瞬时转染等研究方法鉴定了PNRC与SF1的相互作用位点 .结果显示 ,PNRC中氨基酸 2 78～ 30 0区域是与SF1相互作用的位点 .该区域富含脯氨酸 ,其中有 1个SH3结合模体 (motif) ,单独的SH3模体不足以与SF1产生有效的相互作用 .瞬时转染分析表明 ,PNRC 2 70 32 7对野生型PNRC的辅激活功能具有负显性抑制效应 .研究结果表明 ,含SH3结合模体的PNRC 2 78 30 0区域是与SF1相互作用的位点     

Antibacterial activity of novel naphthoquiones derivatives

l,4-naphthoquinone moiety is Known to confer numerous molecules with distinct-hiological activities including anti -mycobacterial, anticancer and anti-inflammatory activities. Vitamin K2, doxorubicin and mitomycin are among the few examples of this class of chemicals used in the treatment of bleeding, lymphoma and carcinoma respectively. Although the exact action mechanism of these molecules is still under investigation, proposed mechanisms include their interact ion with DNA inhibition of topoisomerase II, and production of ROS, contributing individually or in combination with DNA damage and cell death . In the present study, 6 naphthoquinones were synthesized and assayed for their antimicrobial activity againstStaphylococcus aureus by disc diffusion assay and spectrophotometric analys is. DNA topoisomerase II activity was also measured to investigate the degreee of conformation change of a test plasmid DNA affected by the naphthoquinone deriva tives.