Identification of small peptides mimicking the R2 C‐terminus of Mycobacterium tuberculosis ribonucleotide reductase

Ribonucleotide reductase (RNR) is a viable target for new drugs against the causative agent of tuberculosis, Mycobacterium tuberculosis. Previous work has shown that an N‐acetylated heptapeptide based on the C‐terminal sequence of the smaller RNR subunit can disrupt the formation of the holoenzyme sufficiently to inhibit its function. Here the synthesis and binding affinity, evaluated by competitive fluorescence polarization, of several truncated and N‐protected peptides are described. The protected single‐amino acid Fmoc‐Trp shows binding affinity comparable to the N‐acetylated heptapeptide, making it an attractive candidate for further development of non‐peptidic RNR inhibitors. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.     

Insights into battles between Mycobacterium tuberculosis and macrophages

As the first line of immune defense for Mycobacterium tuberculosis (Mtb), macrophages also provide a major habitat for Mtb to reside in the host for years. The battles between Mtb and macrophages have been constant since ancient times. Triggered upon Mtb infection, multiple cellular pathways in macrophages are activated to initiate a tailored immune response toward the invading pathogen and regulate the cellular fates of the host as well. Toll-like receptors (TLRs) expressed on macrophages can recognize pathogen-associated-molecular patterns (PAMPs) on Mtb and mediate the production of immune-regulatory cytokines such as tumor necrosis factor (TNF) and type I Interferons (IFNs). In addition, Vitamin D receptor (VDR) and Vitamin D-1-hydroxylase are up-regulated in Mtb-infected macrophages, by which Vitamin D participates in innate immune responses. The signaling pathways that involve TNF, typeI IFNs and Vitamin D are inter-connected, which play critical roles in the regulation of necroptosis, apoptosis, and autophagy of the infected macrophages. This review article summarizes current knowledge about the interactions between Mtb and macrophages, focusing on cellular fates of the Mtb-infected macrophages and the regulatory molecules and cellular pathways involved in those processes.     

Co‐expression of GR79 EPSPS and GAT yields herbicide‐resistant cotton with low glyphosate residues

Glyphosate‐resistant (GR) crops have been adopted on a massive scale by North and South American farmers. Currently, about 80% of the 120 million hectares of the global genetically modified (GM) crops are GR crop varieties. However, the adoption of GR plants in China has not occurred at the same pace, owing to several factors including, among other things, labour markets and the residual effects of glyphosate in transgenic plants. Here, we report the co‐expression of codon‐optimized forms of GR79 EPSPS and N‐acetyltransferase (GAT) genes in cotton. We found five times more resistance to glyphosate with 10‐fold reduction in glyphosate residues in two pGR79 EPSPS‐pGAT co‐expression cotton lines, GGCO2 and GGCO5. The GGCO2 line was used in a hybridization programme to develop new GR cottons. Field trials at five locations during three growing seasons showed that pGR79‐pGAT transgenic cotton lines have the same agronomic performance as conventional varieties, but were USD 390‐495 cheaper to produce per hectare because of the high cost of conventional weed management practices. Our strategy to pyramid these genes clearly worked and thus offers attractive promise for the engineering and breeding of highly resistant low‐glyphosate‐residue cotton varieties.     

不同治疗方案治疗脊柱结核的效果对比

目的:分析不同脊柱结核手术方式在治疗效果和治疗安全性方面的差异。方法:将我院脊柱外科施以手术治疗的89例脊柱结核患者为研究对象,根据手术方法差异分成后路组45例和前路组44例,记录手术评价指标、Cobb角、手术前后美国脊髓损伤学会神经功能(ASIA评分)变化和术后并发症,并对记录结果行统计分析。结果:后路组手术时间(185.71±21.89)min、出血量(503.12±57.81)m L、出院时间(21.43±3.52)d、手术相关不良反应率(6.82%)、Cobb角度(18.34±8.41)°显著低于前路组,而后路组神经损伤治愈率(54.55%)高于前路组,P0.05,存在统计学差异。结论:手术入路能够影响脊柱结核手术的治疗效果,与前入路手术相比,后入路手术在手术简便性、安全性、有效性方面优势明显。     

结核分枝杆菌在动物中的流行与传播

结核分枝杆菌(Mycobacterium tuberculosis)是一种重要的人兽共患病病原菌,人类是其主要宿主。千百年来,由于动物与人类关系密切,动物也成为结核分枝杆菌的重要宿主,且感染结核分枝杆菌的动物还能成为传染源,将其传播至人类和其他动物。关于动物感染结核分枝杆菌已有大量报道,包括大象、非人灵长类动物、貘、海狮、犬、猫、牛、鸟等。本文就结核分枝杆菌在野生动物、家畜中的流行与传播进行介绍,总结其在动物间传播的主要途径。     

肿瘤多药耐药分子机制研究进展

化疗是治疗恶性肿瘤主要方法之一。然而不幸的是,先天或获得性耐药尤其是多药耐药的发生,最终导致化疗失败。因此,深入探讨多药耐药发生的分子机制,寻找可以有效预测肿瘤化疗敏感性的分子标志物以及逆转多药耐药的分子靶点,是提高化疗效果的有效途径。肿瘤多药耐药分子机制错综复杂,本文主要从DNA损伤修复、ABC转运蛋白家族表达和功能异常、肿瘤干细胞、拓扑异构酶活性改变、上皮间质转分化、谷胱甘肽-S-转移酶表达改变、表观遗传学修饰以及缺氧等方面对肿瘤多药耐药分子机制进行阐述。     

多层螺旋CT对肺结核合并肺癌患者的诊断价值

目的:研究多层螺旋CT对肺结核合并肺癌的鉴别诊断价值。方法:选择2013年3月至2015年9月在我院确诊的肺结核合并肺癌患者32例和单纯肺结核患者39例应用多层螺旋CT扫描患者肺部病变情况。结果:肺结核合并肺癌组:陈旧性肺结核28例、活动性肺结核4例;病灶位置经典部位29例、非经典部位3例,合并鳞癌11例、腺癌13例、小细胞癌5例、未分化癌3例;10例结核病灶与肺癌病灶不同侧、13例结核病灶与肺癌病灶同侧不同叶、9例结核病灶于肺癌病灶同侧同叶。单纯性肺结核组胨旧性肺结核36例、活动性肺结核3例;病灶位置经典部位34例(上叶尖段11例、后段9例、下叶背段14例)、非经典部位5例。肺结核合并肺癌组患者分叶征、毛刺征、胸膜凹陷征、阻塞性肺炎及肺不张以及棘状突起比例高于单纯肺结核组,而空泡影比例低于单纯肺结核组,差异具有统计学意义(P0.05);两组钙化、斑片条索影、结节影以及空洞或空腔比较,差异无统计学意义(P0.05)。结论:多层螺旋CT对肺结核合并肺癌具有较高的临床鉴别诊断价值。