调控胆固醇吸收的分子通路

机体内的胆固醇失衡会引发多种疾病,如高胆固醇血症、心脑血管疾病等,而其平衡由胆固醇的合成、吸收、代谢和循环共同维持,其中胆固醇的吸收至关重要。胆固醇的吸收主要发生在小肠和近段空肠,受众多蛋白的调控。尼曼-匹克C1样蛋白1(NPC1L1)负责胆固醇的摄取;ATP结合盒转运蛋白(ABCG5/ABCG8)则抑制胆固醇的吸收,酰基辅酶A-胆固醇酰基转移酶(ACAT)催化胆固醇脂化提高胆固醇吸收;ATP结合盒转运蛋白A1(ABCA1)负责外周组织胆固醇的转运,而这些蛋白又受到其他调控因子的影响。解析胆固醇吸收的分子通路对胆固醇失衡相关疾病的预防及治疗具有重大指导意义。因此,本文就调控胆固醇吸收的分子通路进行综述。     

微生物辅因子平衡的代谢调控

辅因子平衡对于酶制剂、药品和化学品的生产具有重要的作用。为了满足工业化生产的需求,维持辅因子长期有效的平衡是实现代谢流高效化导向目标代谢产物的必要手段。本文在总结辅因子生理功能的基础上,从生化工程和代谢工程两方面分析归纳了辅因子的代谢调控策略,并展望了辅因子进一步精深调控的发展方向。     

微生物次生代谢的分子调控

摘要：微生物次生代谢产物在工业、农业和医药方面具有重要的应用价值,因此其合成调控长期以来倍受关注。近些年的研究表明,次生代谢产物的生物合成往往与产生菌的生理和发育状态紧密相关,其合成过程错综复杂,形成了多水平的调控网络。在目前所知的一万多种天然抗生素中, 约60%以上是链霉菌产生的。因此,本文主要以链霉菌产生的次生代谢产物为主线,以有突出进展的几种抗生素的研究为代表来介绍近年来抗生素生物合成中分子调控的相关进展,并对未来次生代谢合成调控的发展方向提出一点建议。     

内毒素耐受分子调控机理

多种免疫细胞(如单核细胞等)经低剂量内毒素预处理后可产生对高剂量内毒素的耐受,这种免疫反应称之为内毒素耐受.内毒素耐受是一种由细胞因子信号通路下游负反馈激活的,具有防止炎症持续性伤害的免疫稳态维持机制,主要调控因子包括IL-10细胞因子信号通路、细胞因子信号通路抑制因子和IL-1受体相关激酶.另外,在内毒素耐受免疫反应...     

自噬调控细胞代谢平衡的研究进展

自噬是真核生物中一种进化保守的溶酶体或液泡依赖的分解代谢途径.自噬可被分为选择性自噬和非选择性自噬.细胞通过双层或多层膜包裹待降解产物形成自噬体,然后将其运送至溶酶体形成自噬溶酶体降解细胞内物质,自噬有利于维持细胞的代谢平衡,是一种细胞自我保护机制.在营养缺乏时自噬被诱导,能够促进营养物质和代谢产物的利用,在细胞代谢调...     

水稻开花期调控的分子机理研究进展

水稻准确地感知外部环境信号,通过内部复杂的基因网络做出反应,在一年中最适合的时候开花繁殖。与长日促进长日模式植物拟南芥开花相反,短日促进短日模式植物水稻开花。通过对水稻和拟南芥的开花期调控机理的对比分析,发现水稻和拟南芥有着一些相对保守的开花期控制基因,其调控机理也是相似的。另外,水稻也有一些独特的开花期控制基因和开花途径。本文着重从光周期对水稻开花期的调控途径和作用机理角度进行了阐述,并对水稻开花期的自然变异与其育种应用、生物钟关联基因、光中断现象和临界日长现象以及开花期与产量的关系进行了总结。     

中国丝状真菌次级代谢分子调控研究进展

在目前已知的具有生物活性的微生物次级代谢物中约有50%是由丝状真菌产生的,其中包括人们所熟知的青霉素、环孢菌素A以及洛伐他汀等。鉴于丝状真菌次级代谢物在农业、医药和工业上的重要价值,它们的生物合成及其分子调控一直备受关注。丝状真菌次级代谢物的生物合成是一个复杂的过程,一般涉及多步酶学反应,该过程往往受到不同水平的调控。深入了解丝状真菌次级代谢的分子调控机制,可以为其产量的提高、新骨架化合物的发掘以及隐性次级代谢物的激活奠定重要的理论基础。本文以丝状真菌次级代谢分子调控为主线,重点介绍近40年来我国科研工作者在该领域取得的研究进展,并对这一领域未来的发展进行展望。     

长春花次生代谢转录调控的分子机制

本文就长春花体内生物碱生物合成途径中受转录因子调控、外界因素对其诱导和调控以及作用机制的研究进展作介绍。     

Metabolic fate of [14C]-labeled meal protein amino acids in Aedes aegypti mosquitoes

We developed a method to follow the metabolic fate of [(14)C]-labeled Euglena gracilis protein amino acids in Aedes aegypti mosquitoes under three different adult nutritional regimes. Quantitative analysis of blood meal protein amino acid metabolism showed that most of the carbon of the amino acids was either oxidized to CO(2) or excreted as waste. Under the three different adult nutritional regimes, no significant differences in the metabolism of amino acids were found, which indicated that the female A. aegypti mosquitoes possess a substantial capacity of maintaining metabolic homeostasis during a gonotrophic cycle. The amount of maternal glycogen and lipid after egg laying were significantly lower in the mosquitoes that underwent a partial starvation before a blood meal and/or starvation after the blood meal. The content of egg lipid or protein or the number of eggs laid did not show a significant difference among the three different regimes, which indicates that stable fecundity of A. aegypti under the partial starvation before a blood meal and/or starvation after the blood meal seemed to result from a trade-off between current fecundity and future survival after the eggs laid. The methods described in this paper can be applied to a wide range of questions about the effects of environmental conditions on the utilization of blood meal amino acids.     

Metabolic regulation: A control analytic perspective

A possible basis for a quantitative theory of metabolic regulation is outlined. Regulation is defined here as the alteration of reaction properties to augment or counteract the mass-action trend in a network reactions. In living systems the enzymes that catalyze these reactions are the handles through which such alteration is effected. It is shown how the elasticity coefficients of an enzyme-catalyzed reaction with respect to substrates and products are the sum of a massaction term and a regulatory kinetic term; these coefficients therefore distinguish between massaction effects and regulatory effects and are recognized as the key to quantifying regulation. As elasticity coefficients are also basic ingredients of metabolic control analysis, it is possible to relate regulation to such concepts as control, signalling, stability, and homeostasis. The need for care in the choice of relative or absolute changes when considering questions of metabolic regulation is stressed. Although the concepts are illustrated in terms of a simple coupled reaction system, they apply equally to more complex systems. When such systems are divided into reaction blocks, co-response coefficients can be used to measure the elasticities of these blocks.I dedicate this paper to Henrik Kacser, co-founder of and guiding light in the field of metabolic control analysis. His recent death leaves us bereft of a fount of wisdom and kindness, but his work remains as a monument along the path of our search for an understanding of metabolic behavior.     

微生物金属响应蛋白研究进展

微生物金属响应蛋白(Metal responsive proteins)是一类具有金属传感效应的DNA转录调节因子。目前,已研究的该调节因子家族有7个(Ars R-Smt B等)。每个响应蛋白家族的不同代表都可以调节基于不同金属效应物的基因表达,它们不仅调节微生物细胞内与金属内稳态直接相关的基因表达,还可以调节细胞代谢以减少细胞对供应短缺的金属的需求。目前,金属响应蛋白的研究已有一定成果,部分金属响应结合位点的氨基酸残基及调节机制都被确定。本综述总结了不同金属响应蛋白家族的金属转录调节因子,介绍了关于金属调节基因表达机制的现有研究进展,并以Ars R-Smt B家族和Fur家族为例,详细介绍了金属响应结合位点的结构特征与相关表达调控机制。此外,还介绍了不同响应蛋白控制微生物细胞金属水平作用方面的最新进展,以及在生物冶金与微生物环境治理方面的应用前景。     

Oxygen stress and adaptation of a semi-aquatic plant: rice ( Oryza sativa)

One of the major abiotic stresses that affects plant growth and development is anoxia or hypoxia. Rice is a semi-aquatic plant bestowed with the capability of overcoming oxygen limitation for a considerable period of time. For instance, it can withstand submergence stress either by inherent metabolic adaptations (resistant type), or by keeping its leaves above the water surface by continuously elongating the stem (avoiding type). In the former case, an interplay of several metabolic pathways engaged in anaerobic fermentation keeps the submerged plant alive for a certain period of time. In the latter type, also known as deepwater rice, continuous stem elongation brought about by a series of reactions in planta enables the shoot to remain above the water surface and thus maintain respiration and photosynthesis. However, the earliest event, i.e., sensing the oxygen level that brings about all the changes, has not been clearly understood. This paper intends to evaluate the metabolic adaptations of rice plants to oxygen constraints. Electronic Publication     

磷酸化病毒蛋白的生物学功能及形成机制

磷酸化是病毒蛋白常见的一种翻译后修饰,在调控病毒与宿主的代谢中起重要作用。生物体内的代谢活动与细胞内的信号转导密切相关,通过磷酸化和去磷酸化修饰可改变蛋白生物活性,从而调控胞内生物信号的传递。磷酸化修饰的病毒蛋白参与调控病毒复制、病毒增殖和病毒粒子装配等一系列病毒的代谢活动,同时也影响宿主细胞内的信号转导,抑制宿主基因组复制和表达。本文就病毒蛋白的磷酸化修饰位点、其生物学功能及磷酸化修饰的分子机制进行综述,为病毒感染性疾病的防控治疗及药物开发提供参考。