蛋白质规则二级结构中亲-疏水氨基酸的相对使用频率

本文将氨基酸据亲－疏水性按10度简,5度简并进行分类，然后映射于蛋白质规则二级结构中进行计算，用以寻找规则二级结构中亲－疏水氨基酸的使用规律性。     

Physiologically Based Liver Modeling and Risk Assessment

Because of the inherent complexity of biological systems, there is often a choice between a number of apparently equally applicable physiologically based models to describe uptake and metabolism processes in toxicology or risk assessment. These models may fit the particular data sets of interest equally well, but may give quite different parameter estimates or predictions under different (extrapolated) conditions. Such competing models can be discriminated by a number of methods, including potential refutation by means of strategic experiments, and their ability to suitably incorporate all relevant physiological processes. For illustration, three currently used models for steady-state hepatic elimination--the venous equilibration model, the parallel tube model, and the distributed sinusoidal perfusion model--are reviewed and compared with particular reference to their application in the area of risk assessment. The ability of each of the models to describe and incorporate such physiological processes as protein binding, precursor-metabolite relations and hepatic zones of elimination, capillary recruitment, capillary heterogeneity, and intrahepatic shunting is discussed. Differences between the models in hepatic parameter estimation, extrapolation to different conditions, and interspecies scaling are discussed, and criteria for choosing one model over the others are presented. In this case, the distributed model provides the most general framework for describing physiological processes taking place in the liver, and has so far not been experimentally refuted, as have the other two models. These simpler models may, however, provide useful bounds on parameter estimates and on extrapolations and risk assessments.     

Accelerating inference for diffusions observed with measurement error and large sample sizes using approximate Bayesian computation

In recent years, dynamical modelling has been provided with a range of breakthrough methods to perform exact Bayesian inference. However, it is often computationally unfeasible to apply exact statistical methodologies in the context of large data sets and complex models. This paper considers a nonlinear stochastic differential equation model observed with correlated measurement errors and an application to protein folding modelling. An approximate Bayesian computation (ABC)-MCMC algorithm is suggested to allow inference for model parameters within reasonable time constraints. The ABC algorithm uses simulations of ‘subsamples’ from the assumed data-generating model as well as a so-called ‘early-rejection’ strategy to speed up computations in the ABC-MCMC sampler. Using a considerate amount of subsamples does not seem to degrade the quality of the inferential results for the considered applications. A simulation study is conducted to compare our strategy with exact Bayesian inference, the latter resulting two orders of magnitude slower than ABC-MCMC for the considered set-up. Finally, the ABC algorithm is applied to a large size protein data. The suggested methodology is fairly general and not limited to the exemplified model and data.     

蚕桑文化的符号构成及礼治内涵解析

人类文化都是以符号化的思维及符号化的行为表现出来的,并且人类文化的全部发展都依赖于这些不同符号的表达,蚕桑文化也不例外.远古时期的华夏民族群体生活中,留下了内涵丰富的以蚕桑为中心的图像符号、传说及史实记载,从一个侧面反映出古代中国农耕社会的原初面貌以及变迁发展.以桑、蚕、丝为主要内容的蚕桑文化元素,成为华夏民族文化体系的重要组成部分,蚕丝及蚕丝服饰成为儒家文化所倡导的礼治思想的外在表现形式.     

凝固型大米风味酸奶的研制

用大米蛋白或大米蛋白水解物部分替代牛乳粉生产大米风味酸奶,以谷糠乳杆菌和乳酸乳球菌乳酸亚种为发酵菌种,以酸度和感官为评价指标,通过大米蛋白及其水解物添加量、大米蛋白水解度、乳糖补加及蔗糖添加研究对大米风味酸奶酸度和感官的影响。结果表明,大米风味酸奶的酸度和感官评分随大米蛋白添加量的增加而降低。产品酸度随大米蛋白水解度增加而增大,大米蛋白水解度为7.5%时感官得分最高;产品酸度和感官评分随大米水解物添加量增加而降低,大米蛋白水解物添加量在40%以下时,均可生产出合格的大米风味酸奶。补加乳糖对产品酸度和感官无显著影响。添加蔗糖对产品酸度无显著影响,但对产品感官影响显著,蔗糖添加量在4~6%时,大米风味酸奶的感官得分最高,表现为色泽均匀,质地较细腻,未见乳清析出,凝乳稳定,口感较细腻柔滑,酸甜度适中,米香风味浓郁。     

植物生物反应器研究进展

利用转基因植物作为生物反应器生产外源蛋白 ,包括抗体、疫苗、药用蛋白等较之其他生产系统具有很多优越性。本文着重就这一领域的研究进展及存在的问题进行综述。     

27类蛋白质折叠子的识别及其位点的统计分析

从蛋白质的氨基酸序列出发,采用全体分类的分类策略识别27类折叠子.当使用5种矩阵打分的方法识别27类折叠子时,预测结果并不理想,进一步使用了以矩阵打分方法得到的分值及氨基酸的二肽组分共同作为参数的离散增量算法,取得了较好预测效果.总的预测成功率达到了45.43%.     

Models for the analysis of C-reactive protein in statin trials

Elevation in C-reactive protein (CRP) is an independent risk factor for cardiovascular disease progression and levels are reduced by treatment with statins. However, on-treatment CRP, given baseline CRP and treatment, is not normally distributed and outliers exist even when transformations are applied. Although classical non-parametric tests address some of these issues, they do not enable straightforward inclusion of covariate information. The aims of this study were to produce a model that improved efficiency and accuracy of analysis of CRP data. Estimation of treatment effects and identification of outliers were addressed using controlled trials of rosuvastatin. The robust statistical technique of MM-estimation was used to fit models to data in the presence of outliers and was compared with least-squares estimation. To develop the model, appropriate transformations of the response and baseline variables were selected. The model was used to investigate how on-treatment CRP related to baseline CRP and estimated treatment effects with rosuvastatin. On comparing least-squares and MM-estimation, MM-estimation was superior to least-squares estimation in that parameter estimates were more efficient and outliers were clearly identified. Relative reductions in CRP were higher at higher baseline CRP levels. There was also evidence of a dose-response relationship between CRP reductions from baseline and rosuvastatin. Several large outliers were identified, although there did not appear to be any relationships between the incidence of outliers and treatments. In conclusion, using robust estimation to model CRP data is superior to least-squares estimation and non-parametric tests in terms of efficiency, outlier identification and the ability to include covariate information.     

Soy protein based supplementation supports metabolic effects of resistance training in previously untrained middle aged males

Abstract

Objective.?To determine changes in body composition, physical performance, metabolic and hormonal parameters induced by lifestyle counselling, resistance training and resistance training with soy protein based supplemention in middle aged males.

Design.?Randomised controlled study consisting of resistance training without (RT-G) or with (RTS-G) a soy protein based supplement and a control group with lifestyle education only (LE-G).

Subjects.?Forty healthy middle aged men (50–65 years, BMI 25–29.9 kg/m²).

Measurements.?Changes in body weight (BW) and waist circumference (WC) were measured and body composition (BC), fat mass (FM), lean body mass (LBM) were measured by skin fold anthropometry at baseline and after 12 weeks of intervention. In addition, changes in physical fitness, metabolic and hormonal parameters (lipids, glucose, fructosamines, insulin, insulin-like growth factor-1, Leptin, human growth hormone, dehydroepiandrosterone, testosterone, hs-CRP, Il-6) were evaluated.

Results.?Thirty-five participants completed the 12 week study. No significant changes in BW were noted although RM and WC dropped and LBM increased after training, particularly in the RTS group (FM 22.6?±?5.5?kg to 21.2?±?4.7?kg; LBM 68.5?±?7.2?kg to 70.1?±?7.4; p?<?0.01). Subjects in the RTS group experienced more pronounced improvements in the strength measurements than the RT group. After the training intervention there were significant changes in hormonal and metabolic parameters as well as in glycemic control, particularly in the RTS group.

Conclusions.?Our data suggest that resistance training, particularly in combination with a soy protein based supplement improves body composition and metabolic function in middle aged untrained and moderately overweight males.     

热休克因子研究进展

在环境温度升高．或有重金属、氧化剂存在以及致病微生物感染等不利条件下，生物共有的一种分子水平上的适应性变化是一类称之为热休克蛋白（heatshockprokein，HSP）的蛋白质家族合成显著增加，从而使细胞免受伤害得以存活。热休克因子（heatshockfactor，HSF）是热休克蛋白基因（heatshockgene．HSP）的主要调控因子。本文简要介绍了HSF的结构，HSF与热休克元件（heatshockelement．HSE）的相互作用，和HSF活性调节等方面的研究进展．