产黄酮番木瓜内生真菌的筛选和鉴定

为开发植物内生真菌这一微生物资源,采用组织分离法从番木瓜植株的叶片、果实和茎中分离内生真菌。通过黄酮类化合物显色反应、薄层层析法(TLC)、紫外光谱法(UV),对番木瓜内生真菌的次生代谢产物进行初步分析,筛选出1株产黄酮类物质的内生真菌菌株,并利用分生孢子形态特征和真菌内转录间隔区序列(Internal transcribed spacer,ITS)对该菌株进行分析鉴定。结果表明,从番木瓜果实中分离获得编号为G41的内生真菌菌株可归类为青霉属橘青霉(Penicillium citrinum)。研究证实番木瓜果实中存在可产黄酮类物质的内生真菌菌株,具有进一步开发利用的潜在价值。     

孑遗植物桫椤内生真菌的多样性与群落组成（英文）

桫椤为木本蕨类,在世界范围内属于濒危的孑遗植物,关于桫椤内生真菌的研究还未见报道。本文基于形态学特征和DNA序列分析技术,探讨了桫椤内生真菌多样性和群落组成。研究发现,桫椤组织中蕴藏着丰富的真菌资源,内生真菌定殖率达到87.6%;从桫椤的234个生活组织块中,分离到内生真菌291株,被鉴定为64个分类单元;桫椤组织中常见真菌种类大约占内生真菌的60%,其中铺散内曼菌Nemania diffusa表现出明显的分布优势;内生真菌总体多样性指数达到3.53的较高水平,并且表现出叶轴根部羽片叶柄茎皮的分布规律;分析不同组织中内生真菌的相似性系数和聚类结果,发现桫椤的组织性质影响内生真菌的组成和分布;根据物种累积曲线,现有的研究样本中超过80%的内生真菌已经被分离到,研究结果能够反映桫椤内生真菌的多样性和群落组成。通过分析桫椤的叶柄凋落物中真菌定殖率、丰度、多样性、相似性和真菌种类等特征性数值,表明凋落的桫椤组织中真菌的分布特征已经发生了明显改变。     

我国南方不同产量的八角树内生真菌群落研究

八角Illicium verum原产于我国华南和越南北部,是我国传统的香料和药用植物。内生真菌可提高植物生长与产量。然而,八角的产果量与其内生真菌间的关系尚未有人报道。为揭示内生真菌与八角产量的关系,本文分析了广西壮族自治区不同八角产量植株的内生真菌定殖率和群落组成。从60棵植株的叶片中分离到412株内生真菌,并根据形态学和分子生物学方法将其鉴定为22个真菌分类单元。内生真菌群落的优势类群分别为Colletotrichum gloeosporioides、Dermateaceae sp.和Phyllosticta sp. 1。内生真菌定殖率的变化范围为6%-100%,平均值为41%。内生真菌的定殖率与八角产量的回归分析表明,在较低和中等产量的八角植株中,内生真菌定殖率与产量呈正相关,而在高产的八角植株中,内生真菌定殖率与产量呈负相关。     

孑遗植物桫椤内生真菌的多样性与群落组成

桫椤为木本蕨类,在世界范围内属于濒危的孑遗植物,关于桫椤内生真菌的研究还未见报道。本文基于形态学特征和DNA序列分析技术,探讨了桫椤内生真菌多样性和群落组成。研究发现,桫椤组织中蕴藏着丰富的真菌资源,内生真菌定殖率达到87.6%;从桫椤的234个生活组织块中,分离到内生真菌291株,被鉴定为64个分类单元;桫椤组织中常见真菌种类大约占内生真菌的60%,其中铺散内曼菌Nemania diffusa表现出明显的分布优势;内生真菌总体多样性指数达到3.53的较高水平,并且表现出叶轴>根部>羽片>叶柄>茎皮的分布规律;分析不同组织中内生真菌的相似性系数和聚类结果,发现桫椤的组织性质影响内生真菌的组成和分布;根据物种累积曲线,现有的研究样本中超过80%的内生真菌已经被分离到,研究结果能够反映桫椤内生真菌的多样性和群落组成。通过分析桫椤的叶柄凋落物中真菌定殖率、丰度、多样性、相似性和真菌种类等特征性数值,表明凋落的桫椤组织中真菌的分布特征已经发生了明显改变。     

罗汉果内生真菌多样性研究

该文采用传统形态学方法结合r DNA-ITS序列分析,对我国重要药用植物罗汉果中的内生真菌进行了鉴定并研究其多样性。结果表明:采用组织培养法从罗汉果健康植株中共分离得到150株内生真菌,包括罗汉果中雌株的内生真菌96株、雄株的内生真菌54株。122株内生真菌经形态学结合r DNA-ITS序列分析鉴定为9个属,均归属为子囊菌门,包含座囊菌纲(Dothideomycetes)和子囊菌纲(Sordariomycetes)。其中,座囊菌纲(Dothideomycetes)真菌包含3科、3属;子囊菌纲(Sordariomycetes)真菌包含6科、6属。优势属为刺盘孢属(Colletotrichum)和镰刀菌属(Fusarium)。罗汉果雌、雄植株不同组织中内生真菌的定殖率及分离率的变化规律均不相同,雌株中以根中内生真菌的定殖率和分离率最高,叶片中的最低;在雄株中以叶片中的定殖率和分离率最高,根中的最低。不同菌株在雌、雄两种植株的不同组织中的分布均不同,结合内生真菌群落组成的相似性比较结果,表明部分内生真菌对罗汉果雌株和雄株,以及同一植株中的不同组织均具有偏好性。不同组织中内生真菌的多样性指数在0.11~0.69的范围,其中雌株根部的内生真菌多样性指数最高。以上研究结果为后期探究内生真菌与罗汉果互作关系奠定了基础。     

同一生境下白及与黄花白及内生菌群差异的初步研究

为揭示白及与黄花白及内生菌群落特征异同的内在机制,该文运用末端限制性酶切片段长度多态性分析技术对白及和黄花白及叶、茎、块茎、根等组织中内生细菌16S rDNA、内生真菌ITS区进行检测,分析内生菌丰度及多样性指数,运用主成分分析、聚类分析和相关性分析对比白及与黄花白及内生菌差异。结果表明:(1)白及和黄花白及各组织内生细菌H指数为1.77～2.51,内生真菌H指数为1.79～3.18。(2)内生细菌表现为茎、块茎和根中相似,叶中差异较大; 内生真菌则表现出明显的特异性。(3)白及药用部位多糖含量与内生细菌中的7个T-RFs、内生真菌中的2个T-RFs呈相关性,黄花白及药用部位多糖含量与内生细菌中的3个T-RFs、内生真菌中的6个T-RFs呈相关性。综上结果表明,同一生境下,白及和黄花白及内生细菌除叶组织外,其他组织相似,内生真菌则差异显著,部分内生菌和药用部位多糖含量存在相关性。     

不同扩增引物对高通量测序分析盐角草内生真菌多样性的影响

【背景】高通量测序分析作为深入了解环境微生物群落组成的重要方法,已成为植物内生真菌多样性研究的有效手段,然而由于引物的扩增差异,采用不同引物可对实验结果分析造成影响。同时,盐角草作为世界上最耐盐的植物之一,存在着多种功能性的内生真菌,而较为全面介绍其内生真菌组成和多样性的报道鲜见。【目的】为了揭示盐角草内生真菌的多样性,解析不同扩增引物对内生菌多样性分析的影响。【方法】分别采用真菌高通量测序常用引物对ITS1-5F、ITS1-1F、ITS2对采自乌鲁木齐达坂城盐湖的盐角草内生真菌进行扩增,开展其内生真菌OTU的分析。【结果】通过不同引物对扩增并测序共获得102个盐角草内生真菌OTU,涉及真菌界8个门和未分类菌群,其中子囊菌门(Ascomycota)占绝对优势,其次为担子菌门(Basidiomycota);在属层次上,盐角草内生真菌共涉及64个属及20个未分类属,其中Alternaria、Cladosporium、Podospora等3个属为盐角草内生真菌优势菌群。对不同引物对扩增测序结果分析表明,不同引物对扩增对分析内生真菌OTU数量和种类具有明显的影响,在全部所得的102个OTU中,ITS1-5F引物对获得44个OTU、ITS1-1F引物对获得55个OTU、ITS2引物对获得25个OTU,但以上3对引物扩增均检测到的OTU数仅为5个。物种组成和多样性分析表明,内生真菌多样性分析中采用以ITS1-1F为主,ITS1-5F为辅的分析策略,可较为全面地展现内生真菌的多样性。【结论】盐角草存在较为丰富的内生真菌资源,不同扩增引物对高通量分析盐角草内生真菌组成和分布具有明显的影响。     

不同产地杜仲树皮可培养内生真菌群落组成和多样性

以湖南、四川、贵州、河南、安徽、江西和陕西7个产地的杜仲Eucommia ulmoides为研究对象,采用可培养法对树皮内生真菌进行分离培养,结合形态学和分子生物学进行鉴定,并分析不同产地杜仲内生真菌群落组成和多样性差异。结果表明,不同产地杜仲树皮中共分离到真菌545株,隶属于7纲、15目、27科、43属,其中间座壳属Diaporthe为7个产地的共有属,各地优势属不同。在属水平上,四川样本中真菌群落多样性最高,河南样本真菌群落多样性最低。Margalef丰富度指数及Pielou均匀度指数表明,在河南样本中的内生真菌分布最均匀,丰富度最低;贵州样本内生真菌丰富度最高,但最不均匀。相似性分析显示不同产地杜仲树皮内生真菌组成和多样性不同。这些结果揭示了杜仲树皮中内生真菌菌群具有丰富的多样性,7个不同产地的杜仲树皮内生真菌群落组成、相对多度及优势类群皆存在差异。     

白羊草Epichloë属内生真菌的分离鉴定及其重金属耐受性

通过对北方铜业铜矿峪矿十八河尾矿坝的优势植被白羊草进行叶鞘内生真菌分离,并对白羊草内生真菌的形态特征及孢子形态进行描述,同时,选取其中7个菌株进行act G、tef A和tub B扩增、测序和系统发育分析。结果表明,从白羊草中分离出的内生真菌属于为Epichlo3属,菌落正面呈白色,背面浅黄色,白羊草内生真菌生长速度较慢,孢子大小为1.208—8.048μm之间,孢子形态椭圆、球型。根据分子系统发育学分析结果,将白羊草内生真菌鉴定为Epichlo3 sibiria。通过对白羊草内生真菌进行不同浓度的重金属胁迫处理,发现其对重金属具有一定耐受性,具体表现为:Zn2+(120 mg/L)、Cu2+(160 mg/L)、Pb2+(240 mg/L)和Cd2+(8 mg/L)。对丰富天然禾草内生真菌资源,以及铜矿区生态修复过程中,白羊草内生真菌提高宿主抗性方面的应用具有重要意义。     

一株产紫杉醇罗汉松内生真菌的分离和鉴定

[目的]紫杉醇是重要的抗癌药物,主要从罗汉松等植物中提取,为了保护罗汉松等种质资源,本文从罗汉松植株中分离产紫杉醇内生真菌,并对内生真菌所产紫杉醇的抗肿瘤活性进行了分析.[方法]采用组织块法自罗汉松的根、茎、叶等组织中分离内生真菌;通过四唑蓝(Methyl ThiazolylTetrazolium,MTT)比色法筛选有抗肿瘤活性的内生真菌菌株,通过薄层层析(Thin Layer Chro-matography,TLC)和高效液相色谱(High Performance Liquid Chromatography,HPLC)对内生真菌所产活性物质进行鉴定;采用抽提法抽提内生真菌所产紫杉醇,应用Vero细胞对抽提的紫杉醇的活性进行了分析.[结果]从罗汉松属(Podocrapus)植物中分离到155株内生真菌,其中28株内生真菌具有较高的抑癌活性.将其中一株菌株A2命名为EPTP-1,经形态学和分子分类学分析鉴定为烟曲霉(Aspergillus fumigatus).菌株EPTP-1中抽提的紫杉醇5.553μg/L～555.3 μg/L作用24h表现出明显的致细胞凋亡作用.菌株EPTP-1发酵5天时紫杉醇的产率为0.5578±0.0294 mg/L.[结论]从罗汉松中分离到了一株产紫杉醇内生真菌EPTP-1,可作为紫杉醇类药物工业化生产的候选菌株.     

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     

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.     

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.     

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.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

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).     

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.