内蒙古草甸草原土壤理化性质和微生物学特性对刈割与氮添加的响应

频繁的刈割和氮输入增加是导致草地生态系统退化的重要原因.土壤微生物学特性作为评估土壤质量的重要生物学指标,对草地刈割和氮输入增加的响应规律仍不十分明确.本研究依托内蒙古呼伦贝尔草原刈割复合氮添加野外实验平台,分析了土壤理化性质、土壤微生物生物量、土壤呼吸和土壤酶对刈割、氮添加的响应及其生长季动态变化.结果表明: 刈割显著降低了土壤微生物生物量碳、氮、磷和土壤呼吸(基础呼吸和底物诱导呼吸),与刈割后导致的水分限制及碳限制有关.刈割显著降低了氮磷获取酶(N-乙酰-β-D-葡萄糖苷酶和酸性磷酸单酯酶)的活性,符合“资源分配假说”.氮添加显著降低土壤pH值,但土壤微生物生物量对氮添加和pH降低均无显著响应,表明氮输入增加引起的土壤酸化不是影响微生物生物量的主要因素.氮添加对土壤呼吸和酶活性也无显著影响,与以往在典型草原的大多数研究结果不一致.刈割和氮添加复合处理显著降低了土壤微生物生物量磷,但提高了土壤中有效磷含量,降低了酸性磷酸酶活性.微生物生物量碳、氮、磷和土壤呼吸等的相关参数均在7月最高,这与夏季高温多雨有关.土壤酶活性在春夏季较高,生长季末期较低.这表明在该草甸草原,刈割将导致土壤碳氮磷养分失衡,从而加剧草原退化;而氮添加在短期内并未对土壤微生物生物量和活性产生显著影响.     

应用GeneXpert MTB/RIF对肺外结核的快速检测及评估

目的 评估GeneXpert MTB/RIF检测肺外结核分枝杆菌的准确性,并与传统方法进行比较。 方法 选取2016年6月至2017年6月在本院就诊的144例疑似肺外结核病患者,对所有标本分别进行金胺“O”荧光染色镜检、液体培养及药敏试验、固体培养及比例法体外药敏试验和Xpert法检测。 结果 收集的144例疑似肺外结核标本中,确诊108例,以胸水、淋巴结活检和脓液感染较多,另36例阴性患者中,10例为非结核分枝杆菌感染。Xpert试验的敏感性为28.73%,特异性为96.00%,其阳性预测值和阴性预测值均高于其他3种检测方法。在阳性检出率方面,Xpert试验高于涂片镜检(χ2=17.39,P2=8.64,P2=2.56,P>0.05)。固体培养、液体培养和Xpert试验3种方法对结核分枝杆菌利福平耐药率检测差异无统计学意义(P>0.05),耐药率分别为8.33%、9.68%和11.11%,且Xpert试验方法检测出2株耐多药结核分枝杆菌,平均耗时2.5 h。 结论 GeneXpert MTB/RIF可以作为一种筛选及快速检测工具应用于肺外结核的诊断,同时可作为检测MDR TB的一种指标。     

Studies on Some Properties of the Apoplastic β-N-Acetyl-D-Hexosaminidase from Tomato Leaves

Some properties of the β-N-acetyl-D-hexosaminidase purified from intercellular fluid of tomato leaves after the plant was systematically infected by TMV (tobacco mosaic virus) were studied. When pNP β-D-GlcNAc (p nitrophenyl-N-aeetyl β-D-glucosaminide) or pNP β-D- GalNAc (p-nitrophenyl-N-acetyl-β-D galactosaminide) was used as the substrate, it showed the optical pH between 4. 8--5.0 and optical temperature between 44— 47℃. Studies of thermostabillty indicated that the enzyme had a biphasic denaturation curve. Using pNP-β-D-GIcNAc or pNP-β-D GalNAc as the substrate, the Km value of the enzyme was 0. 36 and 0. 67 mmol/L respectively. N acetyi-D glucosamine and N acetyl-D-galactosamine were competitive inhibitors of the enzyme activities. Ag+ and Hg2+ were sensitive inhibitors and Fe2+ . Fe3+ and Cu2+ were also inhibitors enzyme activities.     

Role of IKK/NF-κB signaling in extinction of conditioned place aversion memory in rats

The inhibitor κB protein kinase/nuclear factor κB (IKK/NF-κB) signaling pathway is critical for synaptic plasticity. However, the role of IKK/NF-κB in drug withdrawal-associated conditioned place aversion (CPA) memory is unknown. Here, we showed that inhibition of IKK/NF-κB by sulphasalazine (SSZ; 10 mM, i.c.v.) selectively blocked the extinction but not acquisition or expression of morphine-induced CPA in rats. The blockade of CPA extinction induced by SSZ was abolished by sodium butyrate, an inhibitor of histone deacetylase. Thus, the IKK/NF-κB signaling pathway might play a critical role in the extinction of morphine-induced CPA in rats and might be a potential pharmacotherapy target for opiate addiction.     

三种不同方法固定的石蜡切片中RNA的分析

研究在 10 %中性福尔马林、丙酮、甲醇 氯仿 冰醋酸 3种方法固定的石蜡切片中提取RNA的质量和数量 .取 2 5 0g体重的Wistar大鼠的肾脏 ,分别采用 10 %中性福尔马林、丙酮、甲醇 氯仿 冰醋酸 3种方法固定 ,石蜡包埋 ,H E染色 ;采用RNA裂解液、TRIZOL试剂 2种方法提取切片RNA ,逆转录为cDNA ,采用普通PCR和SYBRGREEN 1定量PCR分析RNA质量和数量 .结果表明 ,3种固定方法都可保持组织良好的结构和形态 ;采用 2种提取方法 ,均可经RT PCR扩增出 180bp大鼠磷酸甘油醛脱氢酶 (G3PDH)、5 6 5bpβ肌动蛋白 (β actin)、10 0bp纤溶酶系活化剂抑制物 1(PAI 1) ;但采用RNA裂解液时 ,比TRIZOL试剂可提取更多的RNA .     

Immunomodulatory effects of four polysaccharides purified from Erythronium sibiricum bulb on macrophages

Four neutral polysaccharides (ESBP1-1, ESBP1-2, ESBP2-1 and ESBP3-1) were successfully purified from the water extracted crude polysaccharides of Erythronium sibiricum bulbs through the combination of DEAE Sepharose CL-6B and Sephadex G-100 chromatography; their average molecular weights were 1.3?×?10⁴, 1.7?×?10⁴, 9.4?×?10⁵ and 4.1?×?10⁵ Da, respectively. Monosaccharide component analysis indicated that ESBP1-1 and ESBP1-2 were mainly composed of glucose (Glc). ESBP2-1 was composed of Glc, galactose (Gal) and arabinose, with a molar ratio of 24.3:1.1:1, whereas ESBP3-1 comprised Glc and Gal at a molar ratio of 14.8:1. In-vitro study showed that all of the four polysaccharides were able to considerably promote the proliferation and neutral red phagocytosis of RAW 264.7 macrophage cell. They could also stimulate the production of the cell lines’ secretory molecules [nitric oxide, tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β)] in a dose-dependent manner. However, ESBP1-2 was not included in IL-1β. Overall, these results suggested that polysaccharides from E. sibiricum bulbs can be developed as immunomodulatory ingredients for complementary medicines or functional foods. However, further animal or clinical studies are required.

     

Overexpression of polo-like kinase 1 and its clinical significance in human non-small cell lung cancer

Polo-like kinase 1 is a serine/threonine kinase which plays an essential role in mitosis and malignant transformation. The aim of this study was to investigate the prognostic significance of polo-like kinase 1 expression and determine its possibility as a therapeutic target in non-small cell lung cancer. Semi-quantitative RT-PCR assay was performed to detect polo-like kinase 1 mRNA expression in non-small cell lung cancer cells or tissues. Immunohistochemistry was performed to detect polo-like kinase 1 protein expression in 100 non-small cell lung cancer tissue samples, and the associations of polo-like kinase 1 expression with clinicopathological factors or prognosis of non-small cell lung cancer patients were evaluated. RNA interference was employed to inhibit endogenous polo-like kinase 1 expression and analyzed the effects of polo-like kinase 1 inhibition on the malignant phenotypes of non-small cell lung cancer cells including growth, apoptosis, radio- or chemoresistance. Also, the possible molecular mechanisms were also investigated. The levels of polo-like kinase 1 mRNA expression in non-small cell lung cancer cell lines or tissues were significantly higher than those in normal human bronchial epithelial cell line or corresponding non-tumor tissues. High polo-like kinase 1 expression was significantly correlated with advanced clinical stage, higher tumor classification and lymph node metastasis of non-small cell lung cancer patients (P = 0.001, 0.004 and 0.001, respectively). Meanwhile, high polo-like kinase 1 protein expression was also an independent prognostic molecular marker for non-small cell lung cancer patients (hazard ratio: 2.113; 95% confidence interval: 1.326-3.557; P = 0.017). Polo-like kinase 1 inhibition could significantly inhibit in vitro and in vivo proliferation, induce cell arrest of G₂/M phase and apoptosis enhancement in non-small cell lung cancer cells, which might be activation of the p53 pathway and the Cdc25C/cdc2/cyclin B1 feedback loop. Further, inhibition of polo-like kinase 1 could enhance the sensitivity of non-small cell lung cancer cells to taxanes or irradiation. Thus, polo-like kinase 1 might be a prognostic marker and a chemo- or radiotherapeutic target for non-small cell lung cancer.