好氧细菌对多环芳烃降解机制的研究进展

多环芳烃(PAHs)是指两个或两个以上的苯环以线性排列、弯接或簇聚方式构成的一类碳氢化合物.这类化合物广泛分布于环境中,具有潜在的致畸性、致癌性和遗传毒性.在自然环境中,好氧细菌对PAHs的生物降解是一种很重要的方式,凸显其在清除环境PAHs污染物中具有广阔的应用前景.在过去二十多年中,科学家们已经从基因水平上对好氧细菌降解PAHs的机制进行了深入的研究,其中包括PAHs降解基因的多样性、与PAHs降解有关的基因以及细菌群体PAHs遗传适应机制等.在此,就好氧细菌对多环芳烃降解机制的研究进展进行了综述和讨论.     

PAHs降解基因及降解酶研究进展

由于环境中的多环芳烃(PAHs)具有高遗传毒性和"三致"性(致癌、致畸和致突变),其生物降解基因和降解功能酶研究备受关注.多环芳烃双加氧酶是近年来研究较多的多环芳烃降解的关键酶系之一,主要由细菌产生,可通过氧化反应使多环芳烃开环生成小分子的中间产物并最终氧化成CO2和水.目前,有关这类酶的理化性质、结构特点、功能等的研究相继开展,本文对PAHs降解基因、降解酶的研究现状与发展趋势进行综述.     

细菌降解多环芳烃上游途径的遗传学研究进展*

多环芳烃是一类毒性较大的环境污染物。微生物降解和转化是消除此类污染物的理想方法,已发现多种细菌具有这种功能。主要针对细菌在多环芳烃降解中上游途径的代谢酶及基因簇的组成进行综述,阐述了酶的遗传学特点,并探讨了PAHs代谢基因的进化。这有助于了解PAHs的细菌降解机制,并为有效实施生物修复提供理论依据。     

细菌降解多环芳烃上游途径的遗传学研究进展

多环芳烃是一类毒性较大的环境污染物。微生物降解和转化是消除此类污染物的理想方法,已发现多种细菌具有这种功能。主要针对细菌在多环芳烃降解中上游途径的代谢酶及基因簇的组成进行综述,阐述了酶的遗传学特点,并探讨了PAHs代谢基因的进化。这有助于了解PAHs的细菌降解机制,并为有效实施生物修复提供理论依据。     

细菌降解萘、菲的代谢途径及相关基因的研究进展

多环芳烃(Polycyclic aromatic hydrocarbons,PAHs)是一类在环境中广泛存在的具有毒性的污染物,微生物降解是其在自然界中降解的主要途径,因而尤为重要。随着研究的深入,关于微生物降解PAHs的分子降解机制、途径等的认识逐渐积累。以下对细菌降解萘、菲的研究进展进行了概述,介绍了萘的水杨酸降解途径,菲的水杨酸、邻苯二甲酸及其他降解途径,同时也包括降解过程中涉及的降解基因簇,如nah-like、phn、phd、nid和nag等以及细菌在PAHs胁迫条件下其他相关基因的表达与调节等方面的最新进展。这些进展可为降解菌株的分子及遗传机制研究提供理论依据,将促进通过基因工程优化降解菌、更有效地检测PAHs环境污染及实现PAHs污染的生物修复。     

多环芳烃厌氧生物降解研究进展

多环芳烃（PAHs）是环境中广泛分布的一类持久性有机污染物,对生态环境和公众健康具有极大危害。微生物降解是环境中去除多环芳烃污染的有效途径,近年来PAHs厌氧生物降解研究逐渐取代好氧降解成为人们关注的重点。本文从PAHs厌氧生物降解的研究背景出发,从不同厌氧还原反应体系、厌氧降解微生物、PAHs厌氧生物转化途径等方面阐述了PAHs厌氧生物降解的研究概况,归纳了对PAHs厌氧生物降解有积极作用的影响因素,提出了PAHs厌氧降解研究目前存在的问题,并对该领域未来研究方向作了简述和展望。希望为多环芳烃厌氧生物降解与环境修复研究与实践提供参考。     

不同介质中多环芳烃光降解及与生物耦合降解研究现状

多环芳烃(PAHs)是环境中广泛存在的一类有机污染物。它的降解一直是人们关注的课题。光降解就是多环芳烃降解的一种重要形式。对在气相、液相和固相不同介质中的PAHs光降解研究进行了综合论述,重点对PAHs在液相介质的降解速率及影响因素、中间产物及降解机制和反应动力学进行了深入探讨,并介绍了光-生物耦合降解多环芳烃的研究进展。建立系统而有效的PAHs光降解研究技术与方法,是目前当务之急。进一步完善PAHs光降解研究的技术与方法,可更准确地研究PAHs光降解机制及影响因素。     

多环芳烃微生物降解基因的研究进展

多环芳烃(PAHs)是环境中普遍存在的一类有机污染物,微生物的降解是PAHs去除的主要途径。近年来,有关PAHs微生物降解途径和代谢产物的研究已有很多报道。小分子PAHs一般可以直接被微生物降解,而大分子PAHs则需要微生物以共代谢的方式降解。在过去20年中,微生物降解PAHs的基因相继被发现,各种基因在调控PAHs降解过程中的功能也越来越清晰。本文概述了PAHs微生物降解基因方面的研究进展,详细介绍了微生物对萘、菲的降解基因,最后对PAHs微生物降解基因的应用前景进行了展望。     

多环芳烃(PAHs)微生物降解的原位表征方法

多环芳烃(polycyclic aromatic hydrocarbons,PAHs)是一类在环境中广泛存在的持久性有机污染物,微生物降解是去除环境中多环芳烃污染的主要途径。传统的有关PAHs微生物降解的研究主要依靠分离培养技术,难以准确认识PAHs微生物降解的原位过程及机制。近年来发展起来的原位表征方法可以在基因及单细胞水平研究PAHs在复杂环境中的微生物降解过程,能够原位表征具有PAHs降解功能的微生物及其功能基因和代谢活性,是阐明PAHs原位降解过程及分子机制的强有力的手段。该文综述了宏基因组技术(meta-genomics)、稳定同位素探针技术(stable isotope probe,SIP)、荧光原位杂交技术(fluorescence in situ hybridization,FISH)、拉曼光谱技术(Raman spectra)以及二次离子质谱技术(secondary ion mass spectrometry,SIMS)等原位表征技术在PAHs微生物降解研究领域的应用及其存在的问题和发展趋势等。PAHs微生物降解过程及机制的原位表征将为缓解与修复PAHs污染提供科学基础。     

微生物降解多环芳烃的研究进展

多环芳烃(PAHs)是具有严重危害的环境污染物质。介绍PAHs的降解菌,降解机理和PAHs的生物修复方面的研究进展。土壤中PAHs的生物修复被认为是解决污染的有效方法,目前,菲的生物降解途径已经比较清楚,但对结构更为复杂的多环芳烃研究较少。文章还对消除环境中多环芳烃的相关生物技术提出展望。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

鸡传染性法氏囊病病毒研究进展

传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).