铅胁迫对黄瓜幼苗抗氧化酶活性及同工酶的影响

采用水培法和聚丙烯酰胺凝胶电泳法,研究铅胁迫对黄瓜幼苗过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性及同工酶的影响.结果表明,铅胁迫下黄瓜幼苗地上部POD活性除第5天外均随铅浓度的增加而逐渐降低,POD同工酶谱带和表达量减少.在0～500 mg·L^-1铅浓度范围内,SOD活性随铅浓度的增加而增加,第7天达到最大值后急剧下降,低于同期对照值,900 mg·L^-1铅处理SOD活性随时间的延长逐步降低,SOD酶谱带和表达量与铅浓度呈负相关.CAT酶谱带无明显变化,而表达量存在差异.     

替换基因片段对流感病毒生长的影响

摘要:【目的】探索流感病毒内部基因对病毒滴度的影响,构建高产流感疫苗种子病毒。【方法】将A/chicken/ZJ/China/2013(H5N1) (ZJ)病毒的6个内部基因或点突变体或聚合酶复合物基因逐个替换鸡胚高度适应的A/Puerto Rico/8/1934(H1N1)病毒(PR8)的相同基因,构建重组病毒,通过血凝试验比较重组病毒在鸡胚上的增殖滴度。【结果】PB2基因影响最大,替换后未能产生重组病毒;PB1、PA、M基因替换后,重组病毒滴度分别下降了3.7、3.4、3.0个滴度(log2);NS基因替换后基本没有影响;聚合酶复合体基因替换后,病毒滴度稍有下降(7.6 log2),没有提供像完全来自PR8的聚合酶复合体相同的生长特性(8.4 log2);PR8 PB2基因627位点替换成谷氨酸(E)后,病毒滴度从8.4 log2上升到8.7 log2。【结论】合适优化的基因组合可以通过病毒RNA与蛋白之间、蛋白与蛋白之间的相互作用促进病毒复制,从而筛选出能在鸡胚中高效复制的重组体,为高产流感疫苗的生产奠定基础。     

长效碳酸氢铵缓效机理与环境效应研究

依据长效碳铵的光谱特征、理化特性及其对影响氨挥发的主要因子的分析 ,建立了土壤中氨挥发的数学模式 ,提出了长效碳铵中DCD与从碳铵中离解出来的游离态氨形成分子间氢键的新观点 ,这种弱相互作用力降低了土壤中氨的表观浓度 ,使土壤 pH在氨挥发期间降低了 0 .2～ 0 .4,延缓了NO-3 N形成时间 ,缓解了N损失 .长效碳铵能够调节N素供应的形态、时间与数量 ,减少施用化肥后引起的地面水和地下水硝酸盐的污染 .     

Chinese and Global Distribution of H9 Subtype Avian Influenza Viruses

H9 subtype avian influenza viruses (AIVs) are of significance in poultry and public health, but epidemiological studies about the viruses are scarce. In this study, phylogenetic relationships of the viruses were analyzed based on 1233 previously reported sequences and 745 novel sequences of the viral hemagglutinin gene. The novel sequences were obtained through large-scale surveys conducted in 2008-2011 in China. The results revealed distinct distributions of H9 subtype AIVs in different hosts, sites and regions in China and in the world: (1) the dominant lineage of H9 subtype AIVs in China in recent years is lineage h9.4.2.5 represented by A/chicken/Guangxi/55/2005; (2) the newly emerging lineage h9.4.2.6, represented by A/chicken/Guangdong/FZH/2011, has also become prevalent in China; (3) lineages h9.3.3, h9.4.1 and h9.4.2, represented by A/duck/Hokkaido/26/99, A/quail/Hong Kong/G1/97 and A/chicken/Hong Kong/G9/97, respectively, have become globally dominant in recent years; (4) lineages h9.4.1 and h9.4.2 are likely of more risk to public health than others; (5) different lineages have different transmission features and host tropisms. This study also provided novel experimental data which indicated that the Leu-234 (H9 numbering) motif in the viral hemagglutinin gene is an important but not unique determinant in receptor-binding preference. This report provides a detailed and updated panoramic view of the epidemiological distributions of H9 subtype AIVs globally and in China, and sheds new insights for the prevention of infection in poultry and preparedness for a potential pandemic caused by the viruses.     

Clinical Validation of Automatable Gaussian Normalized CBV in Brain Tumor Analysis: Superior Reproducibility and Slightly Better Association with Survival than Current Standard Manual Normal Appearing White Matter Normalization

PURPOSE: To validate Gaussian normalized cerebral blood volume (GN-nCBV) by association with overall survival (OS) in newly diagnosed glioblastoma patients and compare this association with current standard white matter normalized cerebral blood volume (WN-nCBV). METHODS: We retrieved spin-echo echo-planar dynamic susceptibility contrast MRI acquired after maximal resection and prior to radiation therapy between 2006 and 2011 in 51 adult patients (28 male, 23 female; age 23-87 years) with newly diagnosed glioblastoma. Software code was developed in house to perform Gaussian normalization of CBV to the standard deviation of the whole brain CBV. Three expert readers manually selected regions of interest in tumor and normal-appearing white matter on CBV maps. Receiver operating characteristics (ROC) curves associating nCBV with 15-month OS were calculated for both GN-nCBV and WN-nCBV. Reproducibility and interoperator variability were compared using within-subject coefficient of variation (wCV) and intraclass correlation coefficients (ICCs). RESULTS: GN-nCBV ICC (≥0.82) and wCV (≤21%) were superior to WN-nCBV ICC (0.54-0.55) and wCV (≥46%). The area under the ROC curve analysis demonstrated both GN-nCBV and WN-nCBV to be good predictors of OS, but GN-nCBV was consistently superior, although the difference was not statistically significant. CONCLUSION: GN-nCBV has a slightly better association with clinical gold standard OS than conventional WM-nCBV in our glioblastoma patient cohort. This equivalent or superior validity, combined with the advantages of higher reproducibility, lower interoperator variability, and easier automation, makes GN-nCBV superior to WM-nCBV for clinical and research use in glioma patients. We recommend widespread adoption and incorporation of GN-nCBV into commercial dynamic susceptibility contrast processing software.     

血管内皮细胞生长因子复性条件研究

利用大肠杆菌 BL2 1 (DE3)表达血管内皮细胞生长因子 (VEGF16 5)表达蛋白以包含体形式存在。为了获得有生物活性的蛋白质 ,我们对影响复性的参数 :氧化型、还原型谷胱甘肽比例 ,复性液的 p H值 ,复性时间 ,精氨酸浓度 ,血管内皮细胞生长因子起始浓度进行了较为系统的研究 ,初步获得了具有一定生物活性的 VEGF16 5二聚体蛋白。     

Modeling Disease Severity in Multiple Sclerosis Using Electronic Health Records

Objective

To optimally leverage the scalability and unique features of the electronic health records (EHR) for research that would ultimately improve patient care, we need to accurately identify patients and extract clinically meaningful measures. Using multiple sclerosis (MS) as a proof of principle, we showcased how to leverage routinely collected EHR data to identify patients with a complex neurological disorder and derive an important surrogate measure of disease severity heretofore only available in research settings.

Methods

In a cross-sectional observational study, 5,495 MS patients were identified from the EHR systems of two major referral hospitals using an algorithm that includes codified and narrative information extracted using natural language processing. In the subset of patients who receive neurological care at a MS Center where disease measures have been collected, we used routinely collected EHR data to extract two aggregate indicators of MS severity of clinical relevance multiple sclerosis severity score (MSSS) and brain parenchymal fraction (BPF, a measure of whole brain volume).

Results

The EHR algorithm that identifies MS patients has an area under the curve of 0.958, 83% sensitivity, 92% positive predictive value, and 89% negative predictive value when a 95% specificity threshold is used. The correlation between EHR-derived and true MSSS has a mean R² = 0.38±0.05, and that between EHR-derived and true BPF has a mean R² = 0.22±0.08. To illustrate its clinical relevance, derived MSSS captures the expected difference in disease severity between relapsing-remitting and progressive MS patients after adjusting for sex, age of symptom onset and disease duration (p = 1.56×10⁻¹²).

Conclusion

Incorporation of sophisticated codified and narrative EHR data accurately identifies MS patients and provides estimation of a well-accepted indicator of MS severity that is widely used in research settings but not part of the routine medical records. Similar approaches could be applied to other complex neurological disorders.     

细菌功能调控的重要转录因子PerR

PerR是一类存在于多种细菌中的转录因子。研究证实PerR调控的靶基因包括过氧化氢酶katA、DNA结合蛋白mrgA、铁转运调控子fur、血红素合成基因簇hemAXCDBL以及自身perR等。PerR参与的调控作用在细菌的抗氧化作用、胞内的铁离子动态平衡、以及致病菌致病作用中具有重要的意义。本综述主要从PerR调控的靶基因、参与的生理代谢作用以及PerR转录调控的分子机制等方面进行介绍,以期对我们深入了解细菌的抗逆作用机制提供参考。     

Tubular Mas receptor mediates lipid-induced kidney injury

Obesity-related kidney diseases are becoming serious health problems worldwide, yet the mechanism by which obesity causes kidney injury is not fully understood. The purpose of current study was to investigate the role of Mas receptor in lipid-induced kidney injury. In mice fed with high-fat diet (HFD), the protein abundance of markers of autophagy, endoplasmic reticulum stress (ER stress) and apoptosis was dramatically increased in the kidney cortex, which was markedly prevented by Mas deletion (Mas^−/−) or Mas receptor antagonist A779. Palmitic acid (PA) induced persistently increased autophagy, ER stress, and apoptosis as well as mitochondrial injuries in primary cultured proximal tubular cells from wild type, but not from Mas^−/− mice. In human proximal tubular HK2 cells, PA-induced autophagy and ER stress was aggravated by Mas agonists Ang (1–7) or AVE0991, but attenuated by A779 or Mas knockdown. Stimulation of Mas resulted in elevated intracellular calcium levels [Ca²⁺]_i in HK2 cells treated with PA, whereas inhibition or knockdown of Mas decreased [Ca²⁺]_i. Mitochondrial outer membrane located voltage-dependent anion channel (VDAC1) was markedly upregulated in HK2 cells treated with PA, which was associated with impaired mitochondrial morphology and depolarization. These were enhanced by AVE0991 and suppressed by A779 or Mas knockdown. Mas knockdown in HK2 cells prevented impaired interactions among VDAC1, autophagy adaptor P62, and ubiquitin, induced by PA, leading to a potential ubiquitination of VDAC1. In conclusion, Mas receptor-mediated lipid-induced impaired autophagy and ER stress in the kidney, likely contributing to tubular injuries in obesity-related kidney diseases.Subject terms: Autophagy, Chronic kidney disease