白藜芦醇代谢物的研究进展

白藜芦醇是一些植物在受到生物和非生物胁迫时产生的一种植物抗毒素.它在植物体内会迅速被代谢而生产紫檀芪、云杉新苷、viniferins等代谢物.这些代谢物与白藜芦醇一样具有抗菌、消炎、抗血小板凝集、防止细胞癌变等一系列的生物活性,且有些代谢物的选择性、稳定性远远大于白藜芦醇.本文对白藜芦醇代谢物中几种主要代谢物的合成途径、生物活性、代谢调控、检测方法等进行了综述.     

白藜芦醇抗菌抗病毒作用的研究进展

白藜芦醇是一种天然活性物质,被认为是植物体在恶劣环境下受到病原菌感染,植物自身分泌的一种抗毒素,对植物本身起保护作用。随着对白藜芦醇研究的深入,发现白藜芦醇具有抗肿瘤、抗心血管疾病、治疗突变、抗氧化、抗菌抗炎、保肝、诱导细胞凋亡等生物药理活性。近年来,国内外很多学者对白藜芦醇的部分生物学功能进行了深层研究,但关于白藜芦醇抗菌、抗病毒的研究报道较少,本研究对近年来发现的白藜芦醇可抵抗的病原生物,按细菌、真菌、病毒进行分类列举,并对其部分已知抗菌抗病毒机制进行归纳。     

白藜芦醇在糖尿病治疗中的作用

白藜芦醇(resveratrol)是一种从植物中提取的多酚类化合物,它广泛存在于葡萄等植物中。白藜芦醇具有广泛的生物学活性,抗氧化、抗癌和调节代谢等作用。白藜芦醇在治疗糖尿病(diabetes mellitus, DM)中可有效改善胰岛β细胞功能及刺激胰岛素的分泌。白藜芦醇的作用机制较为复杂,现就白藜芦醇在DM治疗中的作用及机制作一概述。     

白藜芦醇合酶的研究进展

白藜芦醇是一种重要的植物抗毒素,具有多种医疗保健作用,因此其应用前景 非常广泛,已引起多方关注。白藜芦醇合酶是白藜芦醇生物合成途径中的关键酶之一,它催化1分子4-香豆酰辅酶A和3分子丙二酰辅酶A反应合成白藜芦醇,它是白藜芦醇生物合成中惟一必需的酶,关于它的研究已广泛开展起来。本文综述了白藜芦醇的药理活性、白藜芦醇合 酶的酶学性质、诱导途径和机制以及分子生物学方面的研究进展。     

水溶液中白藜芦醇稳定性及降解产物分析

白藜芦醇是一种具有较强抗氧化和防癌、抗癌等生理活性的植物天然产物,其功能与生产是当前的研究热点;然而,白藜芦醇的光稳定性和热稳定性较差。在微生物发酵生产及存储过程中需要采取特殊的工艺,以防止其降解,使得发酵及存储工艺复杂化,增加了成本。本研究对发酵及存储过程中的各类条件,如温度、pH、培养基成分及大肠杆菌对白藜芦醇的降解情况进行了初步的研究;使用液相色谱-离子阱-飞行时间质谱,对白藜芦醇的降解产物进行了分析。本研究可作为基础资料,为降低发酵生产及存储过程中白藜芦醇的降解提供重要参考。     

白藜芦醇生物学活性研究进展

白藜芦醇是一种植物抗毒素,主要存在于虎杖、葡萄及花生等有限的植物中,它具有对人体有益的生物学活性,如具有拮抗肿瘤作用、心血管保护作用、抗炎作用、抗病毒作用、神经保护作用、植物雌激素作用和对骨钙的影响等。     

白藜芦醇合酶的研究进展

白藜芦醇是一种重要的植物抗毒素,具有多种医疗保健作用,因此其应用前景非常广泛,已引起多方关注。白藜芦醇合酶是白藜芦醇生物合成途径中的关键酶之一,它催化1分子4—香豆酰辅酶A和3分子丙二酰辅酶A反应合成白藜芦醇,它是白藜芦醇生物合成中惟一必需的酶,关于它的研究已广泛开展起来。本文综述了白藜芦醇的药理活性、白藜芦醇合酶的酶学性质、诱导途径和机制以及分子生物学方面的研究进展。     

微生物合成白藜芦醇的研究进展

白藜芦醇是植物源的多酚化合物,具有清除自由基、抗氧化、延长寿命等生理活性,在医药、保健品、化妆品等方面有着广阔的应用前景。目前,白藜芦醇主要采用植物提取的方法,对自然植物资源依赖严重,而且受植物成分含量和提取效率低的限制。近年来,合成生物学的迅速发展已使人们将注意力转向利用微生物合成白藜芦醇。通过在微生物中转入外源基因,成功构建出了白藜芦醇工程菌株,并从基因序列、组合方式及发酵工艺等方面进行了优化改造。本文综述了微生物合成白藜芦醇的研究进展。     

白藜芦醇的生理作用及其在制剂中应用

作为一种活性物质,白藜芦醇在藜芦、花生、虎杖、葡萄、决明等植物中广泛存在,此外,它在红葡萄酒中也是主要保健成分之一。白藜芦醇的生物学作用非常之多,例如保肝、抗炎、抗肿瘤、调节血脂、抗病原微生物等作用都是对人体大有益处的。本文从白藜芦醇的性质出发,分析了其生理作用及其在制剂中的应用,以期为相关领域的学者提供一些参考。     

白藜芦醇合成酶基因在基因工程中的应用及功能研究进展

白藜芦醇合成酶(Resveratrol synthase,RS)是白藜芦醇(Resveratrol,Res)合成途径中的关键酶。以往研究报道,RS基因已在多种植物和微生物中进行了转化和表达,并在植物的代谢及调控等方面发挥生物学作用。文中主要围绕RS基因对植物的转化,及异源表达后植物体内代谢产物的变化,转RS基因对植物抗病原菌活性、抗自由基活性和生长发育的影响,以及利用RS基因在微生物中生产Res的相关进展进行了综述。并对RS基因在生物工程方面的应用前景进行展望。     

The cannabinoid system and cytokine network

Many advances have been made in the last few years concerning our understanding of the receptors and ligands composing the cannabinoid system. Likewise, the science surrounding cytokine biology has advanced enabling us to measure these proteins more precisely as well as understand and interpret the meaning of changes in their levels. Scientists wishing to study the health consequences of smoking marijuana as well as understand the possible role of endogenous cannabimimetic ligands in immune regulation have continued to study the influence of these substances on the regulation and development of the cytokine network. Research has shown that two major cannabinoid receptor subtypes exist and that subtype 1 (CB1) is expressed primarily in the brain whereas subtype 2 (CB2) is expressed primarily in the periphery. A variety of ligands for these receptors based on the cannabinoid structure have been synthesized and studied as well as low affinity compounds, noncannabinoid ligands, and endogenous ligands derived from fatty acid eicosanoids. Highly selective receptor antagonists have also been introduced and studied. Synthetic, low affinity ligands such as (+)-HU-211 and DMH-11C have been shown to cause anti-inflammatory effects possibly through inhibiting the production and action of TNF-alpha and other acute phase cytokines. In addition, suppression of TNF and other cytokines such as GM-CSF, IL-6, IFNgamma, and IL-12 has also been seen following exposure to high affinity and psychoactive ligands such as marijuana and THC. However, some of these ligands have also been shown to increase rather than decrease interleukins such as IL-1, IL-4, IL-10, and IL-6, cytokines such as TNF-alpha, and chemokines such as IL-8, MIP-1, and RANTES. The endogenous ligand, anandamide, has been shown in culture to either suppress the proliferation response to prolactin or enhance the response to cytokines such as IL-3 and IL-6. This eicosanoid has also been shown to increase the production of interleukins and other cytokines. Cannabinoid receptors have been shown to be involved in some but not all of these effects. It is clear that psychoactive and nonpsychoactive compounds have demonstrated effects in vivo and in vitro on the production and function of a variety of cytokines. Depending upon the model system, these effects are often conflicting, and the involvement of cannabinoid receptors is unclear. However, enough evidence exists to suggest that the cannabinoid system significantly impacts the functioning of the cytokine network, and this association may provide clues to the mechanisms of certain immune diseases and form the basis for new immunotherapies.     

Coumarins scaffolds as COX inhibitors

The discovery of COX enzymes has led to a better understanding of inflammation and its related biological pathways. Apart from being related to inflammation and pain, it has also been associated with cancer and neuropsychiatric diseases such as schizophrenia. Proverbially speaking, study of these enzymes has been crucial as they happen to “have fingers in many pies”. Non-steroidal anti-inflammatory drugs (NSAID) that act specifically as COX-2 inhibitors have been known for a while; however these are also associated with severe side effects such as cardiac problems. Several heterocylic molecules have been tested for their anti-inflammatory activity specifically as COX-inhibitors. Coumarins also known as benzopyrans are widely found in nature, and are routinely employed as herbal remedies since early days. Over 1300 coumarins have been identified, principally as secondary metabolites in green plants, fungi and bacteria. Recently the use of natural and synthetic coumarins has garnered a lot of attention for their anti-inflammatory activities. In this review we delve further into the study of natural and synthetic coumarins as COX-inhibitors. Although the study is still in its nascent stage, we believe there is scope for a lot of development.     

Get a grip: Podosomes as potential players in phagocytosis

Podosomes have been known for several decades as micron-sized, F-actin-rich structures that play a pivotal role in cell migration and invasion, as they are able to mediate both cell-matrix attachment as well as extracellular matrix degradation. Particularly in monocytic cells, podosomes have been shown to fulfill a variety of additional functions such as sensing of substrate rigidity and topography, or cell-cell fusion. Increasing evidence now points to the involvement of podosome-like structures also during phagocytosis by immune cells such as macrophages, dendritic cells, and neutrophils. Here, we compare the different cell models and experimental set ups where “phagocytic podosomes” have been described. We also discuss the composition and architecture of these structures, their potential involvement in mechanosensing and particle disruption, as well as the pros and cons for addressing them as bona fide podosomes.     

Living krill,zooplankton and experimental investigations: a discourse on the role of krill and their experimental study in marine ecology

Krill occupy critical positions in a many marine ecosystems and have been the subject of a number of concerted studies yet there are large areas of their biology that still remain a mystery. Most species of krill are open ocean animals, which makes direct observation and sampling difficult. Krill also exhibit a number of physiological and behavioural attributes which frustrate attempts to understand their life history. Krill are conceptually difficult to come to terms with; they are obviously different from larger marine organisms such as squid, fish, whales and fish yet they are also quite distinct from those animals classed as zooplankton such as copepods. Despite these differences they have most often been grouped with zooplankton and have been studied using techniques developed for animals which are orders of magnitude smaller than they. This mismatch has affected our view of their interactions with the physical world and also affects their perceived trophic interactions. Their size and mobility also interferes with our ability to sample them effectively and thus to develop our appreciation of their true role in the marine ecosystem. Understanding how intermediate-sized animals, such as krill, function in aquatic ecosystem is critical to better management of the marine environment.     

Living krill, zooplankton and experimental investigations: a discourse on the role of krill and their experimental study in marine ecology

Krill occupy critical positions in a many marine ecosystems and have been the subject of a number of concerted studies yet there are large areas of their biology that still remain a mystery. Most species of krill are open ocean animals, which makes direct observation and sampling difficult. Krill also exhibit a number of physiological and behavioural attributes which frustrate attempts to understand their life history. Krill are conceptually difficult to come to terms with; they are obviously different from larger marine organisms such as squid, fish, whales and fish yet they are also quite distinct from those animals classed as zooplankton such as copepods. Despite these differences they have most often been grouped with zooplankton and have been studied using techniques developed for animals which are orders of magnitude smaller than they. This mismatch has affected our view of their interactions with the physical world and also affects their perceived trophic interactions. Their size and mobility also interferes with our ability to sample them effectively and thus to develop our appreciation of their true role in the marine ecosystem. Understanding how intermediate-sized animals, such as krill, function in aquatic ecosystem is critical to better management of the marine environment.     

杀虫剂抗性: 遗传学、基因组学及应用启示

杀虫剂抗性已成为害虫防治工作需要解决的一个重要问题,也是一种人为的、自然选择的重要的进化现象,开展抗药性的研究不仅为抗性的监测、治理和农药工业的发展提供科学参考,还可以揭示生物进化的一些基本规律。在过去的10年,昆虫对许多化学杀虫剂抗药性的分子基础得到了进一步阐明,已从果蝇Drosophila melanogaster中克隆了杀虫剂的靶标基因,还查明了一些害虫的与抗性相关联的基因突变。最近,随着经注释的昆虫基因组的出现,由复杂多基因酶系如酯酶、细胞色素P450酶及谷胱甘肽S-转移酶介导的抗性的机制有了突破性的进展,有关杀虫剂抗性的进化以及抗性基因的传播模式也逐步得到揭示。基因组技术在揭示昆虫其他可能的抗药性机制以及在发现新的杀虫剂靶标方面将发挥更大的作用。     

Engineering Thermostable Microbial Xylanases Toward its Industrial Applications

Xylanases are one of the important hydrolytic enzymes which hydrolyze the β-1, 4 xylosidic linkage of the backbone of the xylan polymeric chain which consists of xylose subunits. Xylanases are mainly found in plant cell walls and are produced by several kinds of microorganisms such as fungi, bacteria, yeast, and some protozoans. The fungi are considered as most potent xylanase producers than that of yeast and bacteria. There is a broad series of industrial applications for the thermostable xylanase as an industrial enzyme. Thermostable xylanases have been used in a number of industries such as paper and pulp industry, biofuel industry, food and feed industry, textile industry, etc. The present review explores xylanase–substrate interactions using gene-editing tools toward the comprehension in improvement in industrial stability of xylanases. The various protein-engineering and metabolic-engineering methods have also been explored to improve operational stability of xylanase. Thermostable xylanases have also been used for improvement in animal feed nutritional value. Furthermore, they have been used directly in bakery and breweries, including a major use in paper and pulp industry as a biobleaching agent. This present review envisages some of such applications of thermostable xylanases for their bioengineering.