MIMLRBF预测谷物蛋白质功能方法的改进

随着人们对营养与保健功能的关注,谷物蛋白质功能预测已经成为当前研究热点.面对大量已完成测序的谷物蛋白质基因组数据,利用计算方法来预测谷物蛋白质功能已经成为主流.从谷物蛋白质结构域序列出发,首次将MIMLRBF算法运用到蛋白质功能预测,并在此算法基础上,提出了多种改进后的谷物蛋白质功能预测模型.其中,针对平均Hausdo...     

高强度船板钢A36的化学成分设计和控制轧制工艺分析

介绍了铌在高强度船板钢A36中的实际应用,分析了邯钢高强度船板钢A36的微合金化和控制轧制工艺,及其对高强度船板钢性能的影响,提出了优化微合金化和控制轧制工艺的具体措施.     

Investigation of Chemical Constituents of Eranthis longistipitata (Ranunculaceae): Coumarins and Furochromones

Aqueous-ethanol extracts (70%) from the leaves of Eranthis longistipitata Regel. (Ranunculaceae Juss.)—collected from natural populations of Kyrgyzstan—were studied by liquid chromatography with high-resolution mass spectrometry (LC-HRMS). There was no variation of the metabolic profiles among plants that were collected from different populations. More than 160 compounds were found in the leaves, of which 72 were identified to the class level and 58 to the individual-compound level. The class of flavonoids proved to be the most widely represented (19 compounds), including six aglycones [quercetin, kaempferol, aromadendrin, 6-methoxytaxifolin, phloretin, and (+)-catechin] and mono- and diglycosides (the other 13 compounds). In the analyzed samples of E. longistipitata, 14 fatty acid–related compounds were identified, but coumarins and furochromones that were found in E. longistipitata were the most interesting result; furochromones khelloside, khellin, visnagin, and cimifugin were found in E. longistipitata for the first time. Coumarins 5,7-dihydroxy-4-methylcoumarin, scoparone, fraxetin, and luvangetin and furochromones methoxsalen, 5-O-methylvisammioside, and visamminol-3′-O-glucoside were detected for the first time in the genus Eranthis Salisb. For all the above compounds, the structural formulas are given. Furthermore, detailed information (with structural formulas) is provided on the diversity of chromones and furochromones in other representatives of Eranthis. The presence of chromones in plants of the genus Eranthis confirms its closeness to the genus Actaea L. because chromones are synthesized by normal physiological processes only in these members of the Ranunculaceae family.     

Is Protein Folding a Thermodynamically Unfavorable,Active, Energy-Dependent Process?

The prevailing current view of protein folding is the thermodynamic hypothesis, under which the native folded conformation of a protein corresponds to the global minimum of Gibbs free energy G. We question this concept and show that the empirical evidence behind the thermodynamic hypothesis of folding is far from strong. Furthermore, physical theory-based approaches to the prediction of protein folds and their folding pathways so far have invariably failed except for some very small proteins, despite decades of intensive theory development and the enormous increase of computer power. The recent spectacular successes in protein structure prediction owe to evolutionary modeling of amino acid sequence substitutions enhanced by deep learning methods, but even these breakthroughs provide no information on the protein folding mechanisms and pathways. We discuss an alternative view of protein folding, under which the native state of most proteins does not occupy the global free energy minimum, but rather, a local minimum on a fluctuating free energy landscape. We further argue that ΔG of folding is likely to be positive for the majority of proteins, which therefore fold into their native conformations only through interactions with the energy-dependent molecular machinery of living cells, in particular, the translation system and chaperones. Accordingly, protein folding should be modeled as it occurs in vivo, that is, as a non-equilibrium, active, energy-dependent process.     

MTEP,a Selective mGluR5 Antagonist,Had a Neuroprotective Effect but Did Not Prevent the Development of Spontaneous Recurrent Seizures and Behavioral Comorbidities in the Rat Lithium–Pilocarpine Model of Epilepsy

Metabotropic glutamate receptors (mGluRs) are expressed predominantly on neurons and glial cells and are involved in the modulation of a wide range of signal transduction cascades. Therefore, different subtypes of mGluRs are considered a promising target for the treatment of various brain diseases. Previous studies have demonstrated the seizure-induced upregulation of mGluR5; however, its functional significance is still unclear. In the present study, we aimed to clarify the effect of treatment with the selective mGluR5 antagonist 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]-pyridine (MTEP) on epileptogenesis and behavioral impairments in rats using the lithium–pilocarpine model. We found that the administration of MTEP during the latent phase of the model did not improve survival, prevent the development of epilepsy, or attenuate its manifestations in rats. However, MTEP treatment completely prevented neuronal loss and partially attenuated astrogliosis in the hippocampus. An increase in excitatory amino acid transporter 2 expression, which has been detected in treated rats, may prevent excitotoxicity and be a potential mechanism of neuroprotection. We also found that MTEP administration did not prevent the behavioral comorbidities such as depressive-like behavior, motor hyperactivity, reduction of exploratory behavior, and cognitive impairments typical in the lithium–pilocarpine model. Thus, despite the distinct neuroprotective effect, the MTEP treatment was ineffective in preventing epilepsy.     

可生物降解聚癸二酸丙三醇酯弹性体的组成及结晶性能

在不同摩尔比条件下,利用丙三醇和癸二酸通过熔融共缩聚反应方法合成了可生物降解的聚癸二酸丙三醇酯弹性体(PGS)。通过溶胀实验、X射线衍射分析及差示扫描量热分析对其组成和结晶性能进行了表征。结果表明,PGS是一种由溶胶和凝胶组成的低交联度聚酯,其中溶胶含量大于75%;PGS的玻璃化转变温度低于-25℃;当癸二酸用量增加时,PGS中存在着结晶,具有以非晶相为软区、晶相为硬区的微观相分离结构。     

MgAl2O4对MgO-PSZ陶瓷的烧结与热学性能的影响

研究了MgO-PSZ和MgAl2O4改进的MgO-PSZ陶瓷制备与性能表征.发现MgO摩尔分数为10%稳定的氧化锆陶瓷样品,在室温下主晶相为单斜相,它是由四方相转变而成.样品中加入适量的MgAl2P4后,相组成中立方相含量增加,可以改变样品的抗循环热震性能,这和MgAl2O4加入后引起的晶粒细化以及致密度适度降低有关;其中在急冷温差△t为1075℃(即急冷最高温度为1100℃)时,在1 mol MgO-PSZ样品配料的基础上再加入0.04 mol MgAl2O4,所获得样品的残余强度率为81%,且在此温度下热震5次后出现裂纹;另外加入MgAl2O4后,样品在热处理过程中的相组成稳定性得到提高.