巴尔通体液体培养条件简化及生长曲线观察

【目的】应用一种昆虫细胞培养基作为基础成分培养巴尔通体(Bartonella species),建立一种操作方便、高效稳定的巴尔通体液体培养方法。【方法】昆虫细胞培养基中添加10%胎牛血清,以此为基础培养液分别添加蔗糖和谷氨酰胺,比较这两种成分对汉赛巴尔通体(B.henselae)和五日热巴尔通体(B.quintana)生长的影响并观察其他10种巴尔通体在简化后的培养液中的生长特性。【结果】添加蔗糖和谷氨酰胺不会明显促进巴尔通体的生长,10种巴尔通体在简化后的培养液中均生长良好。不同种巴尔通体生长曲线不同,汉赛巴尔通体和五日热巴尔通体的世代时间分别为5.2 h和4.3 h,生长速度快于固体培养。【结论】以昆虫细胞培养基作为基础成分的培养液适于巴尔通体液体培养,特别是对一些更难培养的巴尔通体提供了一种较好的培养方法。     

中国部分地区实验猕猴巴尔通体感染状况及其遗传特征

【目的】五日热巴尔通体(Bartonella quintana)由体虱在人群中传播,可引起多种人类疾病包括战壕热。为进一步搜集猕猴是五日热巴尔通体自然宿主的证据,本研究调查了国内4个地区实验用猕猴五日热巴尔通体的感染状况,对菌株遗传特征进行了分析。【方法】采集猕猴全血和血清样品各550份,用于菌株分离、核酸和血清IgG抗体检测。应用6个管家基因扩增及测序方法进行菌株鉴定、系统发育及核苷酸多态性分析;应用随机扩增多态性DNA标记(Random amplified polymorphic DNA,RAPD)技术分析不同宿主来源菌株RAPD指纹图谱差异;应用间接免疫荧光法(Indirect immunofluorescence assay,IFA)检测血清中抗五日热巴尔通体IgG抗体水平。【结果】从550只猕猴中分离到8株五日热巴尔通体菌株,带菌率为1.5%;直接PCR检测550份全血核酸的总感染率为8.2%。普通猕猴血清阳性率为19.0%,感染水平明显高于食蟹猕猴(5.6%)。五日热巴尔通体与汉赛巴尔通体RAPD指纹图谱的带型完全不同,猴源和人源五日热巴尔通体菌株Fuller带型基本一致。不同宿主来源菌株核苷酸多态性分析显示,猴源菌株之间差异小,其与人源菌株差异较大。【结论】中国猕猴五日热巴尔通体感染水平较高,普通猕猴自然感染率及抗体水平明显高于食蟹猕猴,猴源与人源菌株的基因型有明显差异。     

中国家猫克氏巴尔通体分离株生物学及分子特征分析

摘要：【目的】分析中国家猫中分离的巴尔通体菌株M9HN-SHQ生物学性状和分子特征。【方法】应用含5％羊血的胰酶大豆琼脂培养基在5％ CO2培养箱中37℃培养6～7 d,革兰氏和吉姆尼茨染色镜下观察形态;应用VITEK ANI厌氧菌鉴定卡进行生化反应鉴定;气相色谱分析方法获取菌体脂肪酸成份组成（CFA）;Etest药敏试条测定对10种抗生素的敏感性;分别应用随机扩增多态性DNA（RAPD）和脉冲场凝胶电泳（PFGE）技术对目标菌株和其他国际标准菌株等绘制DNA指纹图谱;对16S rRNA,gltA,gro     

深圳海域6株破囊壶菌的生长特性及油脂成分分析

【目的】从深圳海域分离得到6株破囊壶菌,对其基本形态特征、生活史和油脂含量等进行研究,开发其应用潜力。【方法】使用松花粉垂钓法对破囊壶菌进行分离,通过18S r RNA基因测序的方法对破囊壶菌进行鉴定,用显微镜观察其基本形态特征,通过使用尼罗红(Nile Red)染色法对油脂含量进行定性检测,并用GC-MS分析菌株的油脂含量和组成情况。【结果】18S r RNA基因鉴定其属于Aurantiochytrium sp.、Schizochytrium sp.和Thraustochytrium sp.三个属。破囊壶菌的脂肪酸主要成分为十六碳饱和脂肪酸和二十二碳六烯酸(DHA),其中Mn11和Mn15的饱和脂肪酸含量达到总脂肪酸含量的70%以上,Mn16和Sw7的DHA产量分别达到1.29 g/L和1.26 g/L。【结论】Mn11和Mn15菌株适合用于生物柴油的生产,Mn16和Sw7是DHA发酵生产的潜力菌株。     

青海柴达木极端干旱沙地分离芽孢杆菌的分子鉴定及拮抗活性分析

【目的】研究高原极地环境微生物资源。【方法】采用rep-PCR指纹图谱分析、gyrB基因及16S rDNA基因序列分析等多项分子鉴定技术对分离自青海柴达木极端干旱沙地的8株芽孢杆菌菌株进行分类鉴定;通过平板对峙及接种离体叶片试验检测分离菌株的拮抗活性及对病原菌侵染的防效;采用MALDI-TOF-MS质谱分析生防菌株的活性成分。【结果】8株分离菌株鉴定为Bacillus amyloliquefaciens(6株)、Bacillus axarquiensis(1株)和Bacillus atrophaeus(1株);各菌株对油菜菌核病原真菌(Sclerotinia sclerotiorum)均具有显著的拮抗活性;接种离体叶片试验表明菌株对油菜菌核病菌的侵染具有较好防效;MALDI-TOF-MS质谱分析结果显示菌株DGL1(B.amyloliquefaciens)产生脂肽化合物Fengycin,菌株DGL6(B.axarquiensis)产生脂肽化合物Surfactin、BacillomycinsD和Fengycin,菌株DCD1(B.atrophaeus)产生脂肽化合物Surfactin、Fengycin。【结论】为高原干旱沙地极端环境微生物资源研究及生防菌资源开发和应用提供了研究材料。     

一株新的耐辐射菌Deinococcus guangxiensis sp.nov.的分离鉴定及耐辐射特性分析

摘要：【目的】从广西大学辐射中心辐射源附近被常年辐射的水样中分离并鉴定出新的耐辐射菌株,并对其耐辐射特性进行研究。【方法】通过GBM培养基分离培养得到一株新的耐辐射菌株,命名为WGR700T。应用生理生化试验,脂肪酸含量,(G+C) mol％含量测定以及16S rRNA序列同源性分析等方法对菌株进行鉴定,同时对WGR700T的耐辐射特性进行分析。【结果】菌株WGR700T为革兰氏阴性,杆状,没有鞭毛,不能运动,厌氧并能产生红色素。最佳生长温度和PH分别为37℃和pH7.0,主要的呼吸醌是MK-8,细胞壁内还有鸟氨酸,主要脂肪酸为16:1ω7c, 16:0, 15:1ω6c, iso-15:0和 iso-17:0。G+C含量为64.7mol%。菌株WGR700T具有很强的UV(>728 J/m2)和电离辐射抗性(D10 = 9.8 kGy)。菌株WGR700T和奇异球菌属（Deinococcus）内其它菌种16S rRNA有很高的相似性（87.1-95.6%）。【结论】根据16S rRNA及生理生化特征区别,菌株WGR700T应是奇异球菌属的一个新种,命名为Deinococcus guangxiensis sp. nov. 模式菌株为WGR700T(= CGMCC1.7045T =CICC 10360T = JCM 15082T)。     

一株羽毛降解菌的分离与鉴定

【目的】从土壤中分离并鉴定羽毛降解菌,测定其生长最适温度及起始pH,并观察酶活动态。【方法】采用系列稀释法和选择培养基法筛选目的菌株,基于16S rRNA基因序列及Biolog方法鉴定其分类地位,利用全自动生长曲线分析仪监测菌株的最适生长条件,并通过测定蛋白水解活性观察其酶活动态。【结果】从混合羽毛的土壤样品中筛选到一株羽毛降解菌,命名为菌株GIMN1.015,初步判定该菌株属于芽孢八叠球菌属(Sporosarcina)。最适生长pH为9.0,温度为30°C。蛋白水解活性最高值出现在培养后96 h。【结论】菌株GIMN1.015在利用羽毛角蛋白资源中具有潜在的应用价值。这是芽孢八叠球菌在羽毛降解方面的首次报道。     

一株产甘露聚糖酶菌株的分离鉴定及酶的纯化与性质

【目的】筛选性能良好的产碱性甘露聚糖酶的菌株,对菌株进行多项分类鉴定,分离纯化所产甘露聚糖酶并进行性质研究。【方法】利用碱性魔芋粉培养基分离纯化产甘露聚糖酶的嗜碱菌,通过形态特征观察、生理生化测定、16S rRNA序列分析等实验确定菌株的分类地位。利用硫酸铵沉淀、阴离子交换层析和分子筛层析得到电泳纯的酶,分析了酶的最适温度、最适pH、温度和pH稳定性、NaCl以及金属离子等的耐受性。【结果】从我国内蒙古碱湖样品中分离得到一株产碱性甘露聚糖酶的菌株HMTS15,经过多项分类鉴定显示其是与Bacillus agaradhaerens DSM 8721不同的新菌株。菌株HMTS15所产的甘露聚糖酶反应的最适pH为10.0,最适温度75℃。【结论】多项分类结果鉴定菌株为Bacillus agaradhaerens HMTS15。该菌株产生的碱性甘露聚糖酶与同类其他来源的酶相比具有更好的热稳定性和pH适应性,有进一步的研究价值。     

实时荧光定量TaqMan-MGB探针法检测杆菌样巴尔通体

【目的】应用Taq Man探针实时荧光定量PCR技术建立特异性强、敏感性高和稳定性好的快速杆菌样巴尔通体检测方法。【方法】应用生物信息学方法查找杆菌样巴尔通体特有基因,从中筛选出一段特有的基因序列为模板设计探针和引物。通过比较Ct值和荧光强度确定扩增反应的最佳退火温度、探针和引物浓度;将扩增产物连接到p EASY-T载体上制备标准品,绘制标准曲线,分析扩增效率和线性关系;评估方法的特异性、敏感性及重复性。【结果】优化后退火温度为60°C,探针和引物浓度均为200 nmol/L,反应体系20μL。特异性实验显示只有杆菌样巴尔通体扩增出荧光信号,其他种属细菌均未见荧光信号;标准曲线线性关系良好(R2=1),扩增效率E=98.18%;最低检出限为每个PCR反应3个拷贝;组内和组间的变异系数CV值分别为0.21%–0.42%和0.29%–0.59%,在允许范围内。【结论】研究建立的实时荧光定量Taq Man-MGB探针法特异性强、灵敏度高、稳定性好,可快速检测鉴定杆菌样巴尔通体,为这种巴尔通体所引起的一系列疾病的早期快速诊断、监测和流行病学调查等研究提供有效手段。     

具有抗哈维氏弧菌活性共生真菌HLZ-3菌株的筛选、鉴定及其培养条件

【背景】目前,海水养殖业中主要利用抗生素来防治哈维氏弧菌等病原菌,但抗生素的长期使用或滥用会对环境和人体健康带来危害,因此既环保又有效的生物防治方法具有广阔的应用前景。【目的】从海水产品共生微生物中筛选具有抗菌活性的菌株,对活性菌株进行鉴定并确定其合成抗菌活性物质的培养条件。【方法】利用沙氏和2216E培养基,以稀释涂布平板法从海水养殖动物中分离真菌和细菌;利用牛津杯法测定微生物发酵液抗水产病原哈维氏弧菌的活性;通过菌株的培养特征、形态特征和ITS序列分析对抗菌活性菌株进行鉴定;通过筛选发酵培养基的种类及盐度确定培养条件。【结果】从海蚌、白虾、海蛎子等9种样品中分离出微生物52株,其中真菌30株、细菌22株;筛选得到2株具有抗哈维氏弧菌活性的真菌菌株;其中一株活性菌株HLZ-3被鉴定为塔宾曲霉;菌株HLZ-3合成抗菌活性物质的培养条件为4%NaCl的大米培养基,28°C静置培养2周。【结论】实验结果为进一步分离纯化菌株HLZ-3所产抗菌活性次生代谢产物提供了基础。     

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.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV