骨髓基质干细胞与激素相关缺血性骨坏死

骨髓基质干细胞(Bone marrow stromal cells,BMSCs)是一种具有组织修复和免疫调节功能的多能干细胞,它主要存在于骨髓中,然而,如今我们发现,在其他的一些组织中也存在它的身影,例如:脂肪组织、肌肉组织和肌腱组织等。通过骨髓穿刺的方法可以很容易的获得骨髓基质干细胞,它在体外有很强的增殖能力,即使没有动物血清和人工生长因子也可以用进行细胞培养。缺血性骨坏死可以由很多病因引起,研究发现,自身免疫性疾病和血液系统疾病治疗应用的激素与缺血性骨坏死的发生具有很大的相关性,但是,激素的应用在一些严重的疾病中往往又是不可避免的,这就需要我们找到一种方法来预防和治疗激素相关缺血性骨坏死。现在,治疗缺血性骨坏死的标准方法是髓芯减压术,但到了疾病晚期的时候,髓芯减压术治疗的效果就已经微乎其微了,由于骨髓基质干细胞所具有的分化潜能、易于获得和增殖的能力,使它可能成为治疗缺血性骨坏死的一种潜在的补充方式。     

儿茶素单体EGCG酶法修饰研究及其产物抗氧化活性评价

利用Novozym 435脂肪酶在非水介质中催化儿茶素单体EGCG(表没食子儿茶素没食子酸酯)的酶促酰化反应,以增加EGCG的脂溶性。探讨了溶剂种类、水活度、加酶量、反应时间、反应温度、酰基供体等条件对酰化反应的影响。借助液质联用仪及红外光谱仪对合成产物进行鉴定,表明在叔戊醇体系中,脂肪酶可催化EGCG与丁酸乙烯酯的反应,酰化后EGCG主体结构不变,其分子中引入了四碳链的烷基。对修饰后EGCG抗氧化活性的评价表明:在相同的添加量下,酶修饰EGCG活性略低于未改性EGCG,但是清除DPPH·、O-·2自由基能力总体高于TBHQ、维生素C,清除·OH自由基能力低于TBHQ,高于维生素C。     

高温强光胁迫下外源钙对甜椒(Capsicum fructescens L.)幼苗光合生理特性的影响

为探讨钙(Ca2+)对甜椒幼苗生长的影响,以甜椒品系156为试材,分别喷施清水(对照)、5 mmol·L-1(T5)和10 mmol·L-1Ca Cl2(T10),研究了高温(37℃)强光(1 200μmol·m-2·s-1)胁迫下甜椒幼苗叶片光合作用及叶片中活性氧(ROS)清除酶活性的变化。结果表明,高温强光胁迫条件下,与对照植株相比,外源施钙可维持较高的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)及较低的胞间CO2浓度(Ci)。甜椒幼苗功能叶在高温强光胁迫处理后,T5和T10叶片的1,5-二磷酸核酮糖羧化酶(Rubisco)活性及叶片PSII最大光化学效率(Fv/Fm)较高,表明Ca2+有利于减轻胁迫条件下甜椒幼苗叶片的光抑制现象。另外,高温强光胁迫条件下,植株叶片活性氧清除酶活性和可溶性蛋白含量明显增加,且Ca2+处理(T5和T10)的植株高于对照植株,丙二醛(MDA)含量和相对电导率则明显低于对照,这些结果均表明胁迫条件下外源施钙可以通过提高幼苗叶片ROS清除酶活性和渗透调节物质含量来保护光系统反应中心,从而减轻外界胁迫对植物的伤害。     

微生物学实践课程改革与学生创新能力的培养

微生物学是生命科学专业重要的基础课程,该课程应用性强。培养具有科学创新能力的科研人才和解决实际问题的应用型人才,是地方综合性大学的核心任务。为了更好地实现"学生为主体、教师为主导"的教育理念,对微生物学实践教学的教学内容和方法及师资培养等环节进行了改革,取得了一定的成效,形成了多样化的教学策略,为实践教学改革提供了新的思路。实践证明,学生能很好地掌握实验技能,促进了他们的实践能力和创新能力,提高了他们的科研素质。     

Endophytic microbes <Emphasis Type="Italic">Bacillus</Emphasis> sp. LZR216-regulated root development is dependent on polar auxin transport in <Emphasis Type="Italic">Arabidopsis</Emphasis> seedlings

Key message

Endophytic microbes Bacillus sp. LZR216 isolated from Arabidopsis root promoted Arabidopsis seedlings growth. It may be achieved by promoting the lateral root growth and inhibiting the primary root elongation.

Abstract

Plant roots are colonized by an immense number of microbes, including epiphytic and endophytic microbes. It was found that they have the ability to promote plant growth and protect roots from biotic and abiotic stresses. But little is known about the mechanism of the endophytic microbes-regulated root development. We isolated and identified a Bacillus sp., named as LZR216, of endophytic bacteria from Arabidopsis root. By employing a sterile experimental system, we found that LZR216 promoted the Arabidopsis seedlings growth, which may be achieved by promoting the lateral root growth and inhibiting the primary root elongation. By testing the cell type-specific developmental markers, we demonstrated that Bacillus sp. LZR216 increases the DR5::GUS and DR5::GFP expression but decreases the CYCB1;1::GUS expression in Arabidopsis root tips. Further studies indicated that LZR216 is able to inhibit the meristematic length and decrease the cell division capability but has little effect on the quiescent center function of the root meristem. Subsequently, it was also shown that LZR216 has no significant effects on the primary root length of the pin2 and aux1-7 mutants. Furthermore, LZR216 down-regulates the levels of PIN1-GFP, PIN2-GFP, PIN3-GFP, and AUX1-YFP. In addition, the wild-type Arabidopsis seedlings in the present of 1 or 5 µM NPA (an auxin transport inhibitor) were insensitive to LZR216-inhibited primary root elongation. Collectively, LZR216 regulates the development of root system architecture depending on polar auxin transport. This study shows a new insight on the ability of beneficial endophytic bacteria in regulating postembryonic root development.

     

砣具配合解玉砂雕刻玉器纹饰的可能性分析

玉器是中国传统文化的标志性符号之一,但古代文献中关于玉器加工工艺的记载甚少。人们只能借助模拟实验和加工痕迹的显微分析,来解读古代玉器的制作工艺。至迟出现于商代的砣具,是一种旋转加工工具,它可显著提高玉器表面纹饰的加工效率。以往学界的主流观点是,利用砣具雕刻玉器表面纹饰(雕花)时,其锯片的硬度远低于玉石的硬度,必须添加解玉砂来辅助雕刻。然而,本文的模拟实验表明,即使不使用解玉砂,硬度低于玉石的铁锯片也能为玉器雕花;同时发现使用砣具配合解玉砂并不利于雕花操作,因此对于古代用砣具配合解玉砂来雕花的观点需要审慎解释。再者,古代也有硬度能达到或超过软玉(摩氏硬度为6-6.5)的钢,这种钢砣使用时更无需添加解玉砂。此外,显微分析表明,用现代金刚砂锯片雕花会留下独特的加工痕迹,应可作为鉴伪证据。     

Glucagon-Like Peptide 1 Protects against Hyperglycemic-Induced Endothelial-to-Mesenchymal Transition and Improves Myocardial Dysfunction by Suppressing Poly(ADP-Ribose) Polymerase 1 Activity

Under high glucose conditions, endothelial cells respond by acquiring fibroblast characteristics, that is, endothelial-to-mesenchymal transition (EndMT), contributing to diabetic cardiac fibrosis. Glucagon-like peptide-1 (GLP-1) has cardioprotective properties independent of its glucose-lowering effect. However, the potential mechanism has not been fully clarified. Here we investigated whether GLP-1 inhibits myocardial EndMT in diabetic mice and whether this is mediated by suppressing poly(ADP-ribose) polymerase 1 (PARP-1). Streptozotocin diabetic C57BL/6 mice were treated with or without GLP-1 analog (24 nmol/kg daily) for 24 wks. Transthoracic echocardiography was performed to assess cardiac function. Human aortic endothelial cells (HAECs) were cultured in normal glucose (NG) (5.5 mmol/L) or high glucose (HG) (30 mmol/L) medium with or without GLP-1analog. Immunofluorescent staining and Western blot were performed to evaluate EndMT and PARP-1 activity. Diabetes mellitus attenuated cardiac function and increased cardiac fibrosis. Treatment with the GLP-1 analog improved diabetes mellitus–related cardiac dysfunction and cardiac fibrosis. Immunofluorescence staining revealed that hyperglycemia markedly increased the percentage of von Willebrand factor (vWF)⁺/alpha smooth muscle actin (α-SMA)⁺ cells in total α-SMA⁺ cells in diabetic hearts compared with controls, which was attenuated by GLP-1 analog treatment. In cultured HAECs, immunofluorescent staining and Western blot also showed that both GLP-1 analog and PARP-1 gene silencing could inhibit the HG-induced EndMT. In addition, GLP-1 analog could attenuate PARP-1 activation by decreasing the level of reactive oxygen species (ROS). Therefore, GLP-1 treatment could protect against the hyperglycemia-induced EndMT and myocardial dysfunction. This effect is mediated, at least partially, by suppressing PARP-1 activation.