Optimal pattern recognition procedures and their application

Results on Bayesian classification procedures, optimal on structures such as Markov chain and independent features, are reviewed. Numerical results of predicting protein secondary structure based on Bayesian classification procedures on non-stationary Markov chains are discussed. Complementarity relations for encoding bases in one DNA strand are presented. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 41–54, November–December 2007.     

唐菖蒲两变异株的同功酶及SDS-聚丙烯酰胺凝胶电泳的比较分析

为探讨电子束对唐菖蒲诱变的可行性及不同剂量电子束对其花性状的影响，用不同剂量电子束辐照唐菖蒲“江山美人”球茎，在40Gy和160Gy处理组分别得到了1株花色和花序变异株(M1’和M2’)。对这两变异株和对照以及其相应辐照剂量（40Gy和160Gy）处理组进行了研究。M1代植株叶片的过氧化物酶、过氧化氢酶、淀粉酶和酯酶4种同功酶电泳结果表明，40Gy和160Gy处理组的酶带与对照组的相同，变异株与对照组相比，酶带有所增减。基于同功酶谱带带型，使用SPSS11.5进行了聚类分析并得到聚类树状图。图中显示，供试材料被分成了3个组：对照组（包括40Gy和160Gy处理组与对照），M1’组和M2’组。SDS-聚丙烯酰胺凝胶电泳（SDS-PAGE）分析表明，蛋白表达明显被电子束辐照所抑制，但在这两个变异株中观测到3条特异表达的蛋白条带，分子量分别为96kDa、115.4kDa和137.2kDa，这些特异表达的蛋白可能与花色与花序的调控有关。由此表明，电子束辐照诱导花色与花形突变体是1种有效的途径。     

植物生物反应器在药物蛋白生产中的应用

以植物为生物反应器表达和生产药物蛋白是近十几年来基因工程研究的一大热点．植物药物蛋白的生产具有成本低、安全、有效等优点,但是植物药物蛋白生产中存在表达量低、下游加工处理困难、糖链结构改变等问题,严重限制了植物表达重组药物蛋白的产业化发展．综述了植物生产重组药物蛋白的优缺点,并对潜在的问题及应对策略进行了探讨．     

人口迁移算法在蛋白质折叠模拟中的应用

PMA（population migration algorithrn）算法具有较强的全局搜索能力和稳定性．针对PMA算法的思想，首次提出将人口迁移算法应用于蛋白质的折叠模拟中，并使用该算法求解蛋白质折叠构形预测的二维AB模型，对计算结果进行了分析．     

Eetopie Bone Formation in vivo Indueed by a Novel Synthetie Peptide Derived from BMP-2 Using Porous Collagen Scaffolds

To investigate the osteoinductive and ectopicly osteogenic effects of a novel peptide P24 derived from bone morphogenetic protein 2 （BMP2）, biodegradable collagen scaffolds （CS） were used to load BMP-2-derived peptide solutions with different concentrations （0.4 mg peptide/CS, 0.1 mg peptide/CS and pure CS, respectively）, and the implants were implanted into muscular pockets on the back of Wistar rats. Radiographs and histological analysis were performed to evaluate the ectopic bone effects. Active ectopic bone formation was seen in both groups containing the peptide at different concentration （0.4 mg and 0.1 mg）, whereas no bone formation and only fibrous tissue was seen in the pure CS group. The new bone formation induced by the peptide P24 displayed a dose-dependent and time-dependent efficiency. The new bone formation in the 0.4 mg peptide/CS group significantly increased than that of the 0.1 mg peptide/CS group. This novel BMP-2-derived peptide had excellent osteoinductive and ectopicly osteogenic properties which were similar to those of BMP2.     

基于Spiking神经网络的蛋白质二级结构学习预测模型

从氨基酸序列来预测蛋白质二级结构,是我们理解蛋白质结构和功能的重要一步.本文探讨了基于Spiking神经网络的蛋白质二级结构学习预测模型,利用单个神经网络进行学习取得的效果不明显,而利用级联神经网络,通过结构到结构的学习,能很好地提高学习准确率.     

大肠杆菌无细胞蛋白质合成系统的初步研究

陈海琴，徐志南，汪诚，廖玉华，岑沛霖在近几年来被广泛研究和应用的大肠杆菌无细胞蛋白质合成系统中，大肠杆菌抽提物的制备、底物浓度的配比以及能量再生体系的选择是最关键的几个因素.以绿色荧光蛋白(GFP)为报导基因，以缺失核酸酶I基因的大肠杆菌A19为实验菌株，通过对大肠杆菌无细胞抽提物制备过程中菌体收集时间、细胞破碎压力、后处理条件等参数的摸索和确定、无细胞蛋白质合成系统中底物浓度配比的正交实验优化以及系统中能量再生体系的比较和选择，制备得到了GFP表达量为154 μg/mL的大肠杆菌无细胞蛋白质合成系统，与优化前相比产量提高了29倍.     

Sub-molecular features of single proteins in solution resolved with scanning tunneling microscopy

Scanning tunneling microscopy (STM) can be used to image individual biological molecules, such as proteins, in vacuum or air. This requires sample dehydration and thus may not reflect the native state of the molecule. Extensive efforts have been made to image single proteins in solution using STM; however, the images have revealed only round or oval shapes with no sub-molecular details. Here, we present the sub-molecular features of streptavidin proteins under physiological conditions using a homebuilt low-leakage-current and highstability liquid phase STM. The N-lobe, C-lobe, and C-terminal tail of the epidermal growth factor receptor kinase domains were also resolved in solution. Our results demonstrate that the structure, morphology, and dynamics of a protein molecule can be examined under physiological conditions by the STM.

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Phosphorylcholine polymer nanocapsules prolong the circulation time and reduce the immunogenicity of therapeutic proteins

Protein therapy, wherein therapeutic proteins are delivered to treat disorders, is considered the safest and most direct approach for treating diseases. However, its applications are highly limited by the paucity of efficient strategies for delivering proteins and the rapid clearance of therapeutic proteins in vivo after their administration. Here, we demonstrate a novel strategy that can significantly prolong the circulation time of therapeutic proteins as well as minimize their immunogenicity. This is achieved by encapsulating individual protein molecules with a thin layer of crosslinked phosphorylcholine polymer that resists protein adsorption. Through extensive cellular studies, we demonstrate that the crosslinked phosphorylcholine polymer shell effectively prevents the encapsulated protein from being phagocytosed by macrophages, which play an essential role in the clearance of nanoparticles in vivo. Moreover, the polymer shell prevents the encapsulated protein from being identified by immune cells. As a result, immune responses against the therapeutic protein are effectively suppressed. This work describes a feasible method to prolong the circulation time and reduce the immunogenicity of therapeutic proteins, which may promote the development and application of novel protein therapies in the treatment of diverse diseases.

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Hypomagnesemia as a predictor of mortality in hemodialysis patients and the role of proton pump inhibitors: A cross‐sectional, 1‐year,retrospective cohort study

Introduction This study aimed to evaluate the association between proton pump inhibitor (PPI) use and serum magnesium levels, and the role of hypomagnesemia and PPI use as a risk factor for mortality in hemodialysis patients. Methods An observational study, including a cross‐sectional and 1‐year retrospective cohort study. The study comprised 399 hemodialysis patients at a single center, and was conducted from January to September 2014. Multiple linear regression analysis was used to investigate the independent relationship between serum magnesium levels and baseline demographic and clinical variables, including PPI and histamine‐2 receptor antagonist use. Cox regression model was used to identify lower serum magnesium level and PPI as a predictor of 1‐year mortality. Findings Serum magnesium levels were lower with PPI use than non‐PPI use (2.39 ± 0.36 vs. 2.56 ± 0.39 mg/dL, P < 0.001). Multiple linear regression analysis showed that PPI use, low serum albumin levels, and low serum potassium and high‐sensitivity C‐reactive protein (hs‐CRP) levels were significantly associated with low serum magnesium levels. A total of 29 deaths occurred during the follow‐up period. According to Cox regression analysis stratified by hs‐CRP, only high serum hs‐CRP levels (>4.04 mg/L) in association with low serum magnesium levels was an independent risk factor for 1‐year mortality (hazard ratio: 2.92; 95% CI: 1.53–6.40, P < 0.001). Discussion Serum magnesium levels are lower in PPI use. In the inflammatory state, a low serum magnesium level is a significant predictor of mortality in hemodialysis patients.