一株可同时降解多种高环PAHs的丝状真菌——宛氏拟青霉(Paecilomyces variotii)

采用液体培养的方法,分离纯化了丝状真菌宛氏拟青霉(Paecilomyces variotii)并研究了其对苯并[a]蒽、苯并[a]芘、苯并[b]荧蒽、苯并[k]荧蒽、茚并[1,2,3-cd]芘的降解效果.结果表明:接种处理30 d,该菌株对混合体系中5种PAHs的降解率为16.1%～24.6%,而对单一体系中的降解率为10.4%～33.3%;同时,对单一与混合体系中PAHs的降解作用存在一定差异,苯并[k]荧蒽和苯并[b]荧蒽在单一体系中降解率增大,而其他种类的则减小.本研究结果为高环多环芳烃共代谢机理研究和多环芳烃复合污染水土环境的生物修复提供了一种新的种质资源.     

多环芳烃降解菌的筛选与降解能力测定

从本溪多环芳烃(PAHs)污染土壤中经富集培养筛选出8株PAHs降解菌,研究了8株菌及其等比例混合培养对菲、芘和苯并[a]芘的降解能力。结果表明,在28℃,培养基中菲、芘和苯并[a]芘的浓度分别为50、50和5mg·L-1的复合底物条件下,培养28d后,菌株B3的降解效果最好,对菲、芘和苯并[a]芘的降解率分别为88.4%、54.0%和68.4%,8株菌的混合培养对菲、芘和苯并[a]芘的降解率分别为87.7%、35.3%和42.0%;经生理生化实验和16SrRNA序列比对,初步鉴定B3菌为假单胞菌属(Pseudomonas sp.)。     

高效芘降解菌N12的分离鉴定与降解特性

以芘为目标降解物,利用选择性富集培养方法,从沈抚灌区污染土壤中分离到一株高效芘降解菌N12,经生理生化试验和16S rDNA测序分析,该菌被鉴定为分枝杆菌属（Mycobacterium sp.）.菌株N12能以菲、苊、芴和芘为唯一碳源和能源生长,不能以蒽、萘和苯并芘为唯一碳源和能源生长.在菲和芘共同存在的情况下菌株N12可降解苯并芘,9 d内对苯并芘降解率可达79.0%.摇瓶降解试验表明,菌株N12可在7 d内将100 mg·L^-1的芘降解94.4%,14 d内将其完全降解;可将600 mg·L^-1的芘在7 d内降解56.1%,14 d内降解95.5%.添加葡萄糖可促进N12对芘的降解.菌株N12是一株优良的多环芳烃降解菌,可作为多环芳烃污染土壤生物修复的菌种资源.     

三株降解芘的戈登氏菌鉴定及其降解能力

从沈抚灌区多环芳烃污染土壤中筛选出的芘降解菌D44、D82S和D82Q,经形态观察、生理生化试验和16S rDNA序列分析确定均为戈登氏菌属(Gordonia sp.).3株菌的最适生长pH值均为7,当pH值低于5或高于9时,生长均受到明显抑制.降解试验表明,3株菌能以芘、苯并芘、蒽、萘、菲和荧蒽为唯一碳源和能源生长.经过7 d的培养,3株菌对初始浓度为100 mg.L-1的芘的降解率均在65%以上,对初始浓度为50 mg.L-1的苯并芘的降解率分别为79.6%、91.3%和62.8%.通过PCR检测发现D82Q和D82S含有烷烃单加氧酶基因alkB.     

两株具有芘降解功能的植物内生细菌的分离筛选及其特性

从植物体内筛选具有多环芳烃(PAHs)降解功能的内生细菌并定殖于植物体,有望有效地去除植物体内PAHs,从而减低植物污染风险。采用富集培养法,从长期受PAHs污染的植物体内分离筛选出2株能以芘为唯一碳源和能源生长的内生细菌BJ03和BJ05,经形态观察、生理生化特性及16S rDNA序列同源性分析,将2株菌分别鉴定为不动杆菌属(Acinetobacter sp.)和库克氏菌属(Kocuria sp.)。并研究了2株内生细菌对芘的降解能力及环境条件对其降解芘的影响。结果表明,菌株BJ03和BJ05在以浓度为50 mg/L的芘为唯一碳源生长时,于30℃、150 r/min摇床培养15 d后,对芘的降解率分别为65.0%和53.3%。2株菌在pH值(6.0—9.0)、温度(25—40℃)和盐浓度(NaCl含量为0—15 g/L)条件下生长良好,且皆为好氧生长,通气量越大,菌株生长越旺盛,对芘的降解能力越强。添加C、N源可有效促进菌株BJ03和BJ05的生长,加速其对芘的降解速率。当外加C源为蔗糖、N源为酵母膏时,2株菌在30℃摇床培养4 d后,对芘的降解率分别高达71.1%和55.3%。2株菌的细胞表面疏水率最大分别为93.7%和43.9%,对四环素和利福平敏感,而对其它多种抗生素具有较强的抗性。     

嗜麦芽寡养单胞菌PX1的降解芘特性及定殖效能

为丰富多环芳烃降解菌菌种库、降低农作物的污染风险,本研究对一株可高效降解多环芳烃(PAHs)的植物内生菌进行筛选鉴定,并初步探究其降解途径以及定殖效能。结果表明: 菌株PX1为嗜麦芽寡养单胞菌。该菌株对多环芳烃的降解具有广谱性,7 d几乎可彻底降解PAH无机盐培养基中的萘,在分别含有50.0 mg·L^-1菲、20.0 mg·L^-1芘、20.0 mg·L^-1荧蒽和10.0 mg·L^-1苯并[a]芘的培养体系中,对菲、芘、荧蒽、苯并[a]芘的降解率分别为72.6%、50.7%、31.9%和12.9%。选取芘作为PAHs模型研究菌株PX1的降解特性。酶活性试验表明,芘可诱导菌株PX1体内邻苯二甲酸双加氧酶、邻苯二酚-1,2-双加氧酶和邻苯二酚-2,3-双加氧酶的活性。在芘降解过程中检测到4,5-环氧化芘、4,5-二羟基芘、龙胆酸/原茶儿酸、水杨酸、顺-己二烯二酸/2-羟粘糠酸半醛、顺-2′-羧基苯丙酮酸、1-羟基-2-萘甲酸、水杨醛等中间产物。浸种定殖试验表明,菌株PX1可高效定殖到空心菜和小麦体内,显著促进空心菜和小麦生长,并能够将空心菜、小麦体内及其生长基质中的芘浓度分别降低29.8%～50.7%、52.4%～67.1%和8.0%～15.3%。表明菌株PX1主要通过“水杨酸途径”和“邻苯二甲酸途径”降解芘,且可以定殖到植物体内,促进植物生长。     

分枝杆菌TZh51菌株的分离鉴定及其生物修复污染土壤的特性

[目的]为获得降解芘的微生物菌株,并用其生物修复被多环芳烃污染的土壤.[方法]芘降解菌的分离采用平板升华法.根据表型观察、生理生化特性和16S rDNA的序列同源性分析,对菌株进行分类学鉴定.通过活菌计数、HPLC测定多环芳烃的残留量,研究菌株在固体、液体无机盐培养基以及在污染土壤中降解多环芳烃(polycyclic aromatic hydrocarbons,PAHs)的能力.[结果]分离到4株能降解芘的菌株TZh51、TZh52、TG42和TG52.实验结果表明,TZh51降解PAHs的能力强于其余3株菌.TZh51被鉴定为分枝杆菌属(Mycobacterium sp.),但与已发表的分枝杆菌菌株M11为不同的种.TZh51接种在芘膜的固体无机盐培养基上,测定获得最大芘降解量的条件是培养温度为3512和芘膜厚度为130 ng/mm2.在芘浓度为50、100 mg/L的液体无机盐培养基中培养,6天时TZh51的芘降解率分别达到91.9%、71.8%,10天时菌体数量分别达到最大值为2.0、6.0×108cfu/mL;TZh51降解芘的效果强于M11.在种植作物的处理中,到第6周时TZh51的菌体数量达到每克干土含7.2×108个菌落数,到第8周时菲、荧蒽和芘的降解率分别达到91.4%、86.9%和85.8%;[结论]TZh51具有很强降解PAHs的能力;另外,TZh51与作物联合生物修复污染土壤的效果明显.     

盐碱土壤PAHs 降解菌的筛选鉴定及其降解特性

采用富集培养的方法,从天津大港油田PAHs污染盐碱化土壤中分离出一株能以菲、芘为唯一碳源和能源的优势菌TJB5。经形态观察和16S rDNA序列分析结果表明,该菌株为成团泛菌(Pantoea agglomerans)。采用液体培养的方法,研究了pH、盐度、菲芘的初始浓度对TJB5菌株降解菲芘效果的影响,确定了最佳降解条件。结果表明,该菌对菲、芘的降解具有较广泛的pH、盐度范围和良好的降解效果。在菲、芘浓度分别为50 mg/L、pH 6.8-9.5、盐度2%-3%、温度30°C条件下,接种15 d后菲降解率在93.3%以上,芘降解率在20%以上。     

一株高效降解芘的细菌分离、鉴定及其降解效果

摘要：【目的】获得高效降解高分子量多环芳烃的细菌,并研究其对多环芳烃的降解能力。【方法】利用富集培养和芘升华平板方法,从焦化厂污染土壤中分离多环芳烃降解细菌,对分离菌株通过形态特征、16S rRNA基因和gyrb基因序列相似性分析进行鉴定,并研究该菌对高分子量多环芳烃（HMW-PAHs）的降解效果。【结果】筛选到一株能以芘、苯并蒽、屈、苯并芘、茚并芘、苯并苝、荧恩为碳源和能源生长并降解这些底物的菌株HBS1,该菌株的16S rRNA基因和gyrb基因序列与Gordonia amicalis的相应基因的相似     

乳白耙齿菌F17对单一和复合多环芳烃的降解差异解析

[目的] 针对菲、蒽、荧蒽多环芳烃（PAHs）污染物,利用乳白耙齿菌F17,研究单一和复合PAHs污染物的生物降解规律。[方法] 采用气相色谱-质谱法（GC-MS）分析降解过程中PAHs的浓度,并采用准一级反应动力学模型对降解结果进行拟合。[结果] 对于单一PAHs,第15天时菲、蒽、荧蒽的降解率由高到低依次为菲（97.8%） > 蒽（89.3%） > 荧蒽（81.5%）。菲、蒽和荧蒽的降解过程具有准一级反应动力学特征,菲的生物降解速率最快,其次是蒽,荧蒽的降解速率最慢。与单一PAHs的降解相比,在复合PAHs的降解过程中,乳白耙齿菌F17的生长和锰过氧化物酶的合成均表现出不同的特征。此外,水溶性极可能是复合污染物降解的重要控制因子,三者水溶性为：菲 > 荧蒽 > 蒽。因此,在菲或荧蒽加入条件下,微生物能优先降解这些污染物,抑制了污染物蒽的降解;同时,蒽或菲的存在对荧蒽的降解也有抑制作用;然而外源加入水溶性较差的蒽和荧蒽,则对菲的生物降解无显著影响。[结论] 复合PAHs的生物降解主要表现为相互竞争的特点,通过GC-MS分析了PAHs的生物降解途径。     

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).     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.