高产β-葡萄糖苷酶N1菌株的分类鉴定

从纳豆中分离纯化得到1株β-葡萄糖苷酶高产菌株,命名为N1菌,利用16S rDNA分析对该菌作了系统进化鉴定.首先提取N1菌基因组DNA,根据不同种属细菌的16S rDNA序列两端的保守性设计通用引物,对N1菌16S rDNA片断进行PCR扩增,对扩增得到的目标片段测序,利用BLAST对测序结果进行比对,构建系统进化树进行分析,初步确定该菌属于枯草芽孢杆菌.研究表明以16S rDNA分析对该菌鉴定完全可行.     

一株引起马来甜龙竹组培污染内生菌的分离与鉴定

【目的】对一株引起马来甜龙竹组培污染内生菌的分离与鉴定。【方法】采用改良的NA培养基分离纯化菌株,并通过菌体的形态结构观察、生理生化试验及其16SrDNA序列同源性分析对其进行鉴定。【结果】菌株SWFU01的形态特征及生理生化试验结果与解淀粉芽孢杆菌[Bacillus amyloliquefaciens(Fukumoto)Priest et al.]的描述基本相同;16S rDNA序列分析表明,该菌株与解淀粉芽孢杆菌JS在同一系统发育分支,其同源性为99.28%。【结论】综合形态学特征、生理生化特征以及16S rDNA序列分析的研究结果,菌株SWFU01被鉴定为解淀粉芽孢杆菌。     

水浮莲中一株西瓜枯萎病拮抗菌的分离、筛选及鉴定

从水浮莲(Pistia stratiotes L.)的叶中分离出1株对西瓜枯萎病有明显拮抗作用的内生细菌XJPL-YB-26, 其发酵液上清在280 nm处有最大紫外吸收峰。利用软件Primer 6.0 设计16S rDNA引物并对其基因组DNA进行扩增并测序得到XJPL-YB-26的部分16S rDNA序列, GenBank接收号为EU251191。经Blastn调出与菌株16S rDNA同源的序列, 并用软件MEGA 3.1按Neighbor- Joining方法构建16S rDNA系统发育树。菌株XJPL-YB-26与AB271744处于同一分支, 相似性为99%, 最终鉴定为枯草芽孢杆菌Bacillus subtilis。     

水浮莲中-株西瓜枯萎病拮抗菌的分离、筛选及鉴定

从水浮莲(Pistia stratiotes L.)的叶中分离出1株对西瓜枯萎病有明显拮抗作用的内生细菌XJPL-YB-26,其发酵液上清在280 nm处有最大紫外吸收峰.利用软件Primer 6.0设计16S rDNA引物并对其基因组DNA进行扩增并测序得到XJPL-YB-26的部分16S rDNA序列.GenBank接收号为EU251191.经 Blastn调出与菌株16S rDNA同源的序列,并用软件MEGA 3.1按Neighbor-Joining方法构建16S rDNA系统发育树.菌株XJPL-YB-26与AB271744处于同一分支,相似性为99%,最终鉴定为枯草芽孢杆菌Bacillus subtilis.     

可产酸快生小菌的分离鉴定

目的：鉴定在实验过程中分离到的一株生长快速,并且可以将L-山梨糖转化为2-酮基-L-古龙酸的菌株。方法：将快生小菌传代,并进行产酸、抗菌谱、山梨糖脱氢酶活性等分析,通过PCR方法扩增并分析16S rDNA。结果：在传代过程中还分离得到了不产酸菌株;从快生小菌中扩增得到了普通酮古龙酸菌16S rDNA;从产酸菌中能够扩增得到包含酮古龙酸菌和乙酸钙不动杆菌的16S rDNA序列;在不产酸菌中只检测到乙酸钙不动杆菌的16S rDNA序列。结论：产酸的快生小菌可能是普通酮古龙酸菌和乙酸钙不动杆菌形成的融合细胞,这种融合细胞基因组表现为很不稳定,普通酮古龙酸菌基因组容易丢失,且丢失后也失去了产酸能力。     

兼性厌氧纤维素菌的分离与系统发育分析*

从四川卧龙中国保护大熊猫研究中心提供的野外放归大熊猫“祥祥”的粪样中,分离到一株产纤维素酶的兼性厌氧菌株。该菌株经初步生理生化鉴定为肠杆菌科沙雷氏菌(Serratia),命名为Serratia JF-1116。用PCR技术扩增了该菌的16S rDNA全序列,并对其进行了克隆和测序,对该序列在GenBank中的BLAST结果表明,所有与该序列高度同源的序列均为肠杆菌科的16S rDNA基因序列,选取同源性高的菌株的16S rDNA基因序列进行系统发育分析,菌株与3株Serr     

中药中耐辐射微生物的分离与鉴定

从中成药(金锁丸)中分离获得一种耐辐射的细菌。经过形态观察、生理生化特征分析及16 S rDNA碱基序列测定和同源性分析,鉴定该菌株为弯曲芽孢杆菌(Bacillus flexus),该菌株的16 S rDNA序列已在Gen-Bank中注册,登录号为AB021185.1。     

高碱性纤维素酶产生菌的筛选及鉴定

从化纤厂土样中分离得到菌株AC-4,碱性纤维素酶活力达0.602 IU/mL。通过分析菌株形态学特性、培养特征及16S rDNA序列,确定该菌株为短小芽孢杆菌。对该菌所产碱性纤维素酶的酶学性质进行测定,确定其最适作用pH为9.5,最适作用温度为50℃。     

药用植物内生芽孢杆菌的多样性和系统发育研究

[目的]了解药用植物内生芽孢杆菌的生物多样性.[方法]采用数值分类、16S rDNA PCR RFLP、BOX-PCR指纹图谱和16S rDNA序列分析技术对分离于几种药用植物的内生芽孢杆菌和已知参比菌株进行表型、遗传多样性及系统发育研究.[结果]供试菌株在数值分类聚类分析中在84%的相似水平上产生13个表观群.16S rDNAPCR-RFLP分析表明供试菌株表现出丰富的遗传多样性.BOX-PCR指纹图谱分析进一步证明药用植物的内生芽孢杆菌的基因组也具有多样性,聚群的结果与数值分类有较好一致性.用软件在Genbank中进行所得序列的同源性检索,并构建系统发育树.由16S rDNA序列分析可知,供试的代表菌株SCAU11与球形芽孢杆菌(Bacillus sphaericus)亲缘关系最近,SCAU78和SCAU25为枯草芽孢杆菌(Bacillus subtilis)的两个亚种,代表菌株SCAU39与巨大芽孢杆菌(Bacillus megaterium)的亲缘关系最近.[结论]研究结果表明药用植物内生芽孢杆菌具有明显的表型和遗传多样性.     

新疆盐碱地土壤耐盐芽胞杆菌的分离和鉴定

为了开发利用新疆盐碱地的耐盐菌资源,从该盐碱地土样中分离并纯化出11株耐盐能力较高的菌株,并从形态特征和16S rDNA序列分析对这些菌株进行鉴定。结果表明,11个菌株均为产芽胞,革兰氏阳性细菌。通过对这11个菌株的16S rDNA进行测序和同源性比较,发现它们与芽胞杆菌的相似性均达到99%。因此,这些菌株被鉴定为Bacillus sp.。11株菌均不能在NaCl质量浓度大于220 g/L条件下生长,属于中度耐盐菌株。耐盐基因的PCR扩增结果表明,只有NYT21、23、25、27、29等5株菌株含有pro耐盐基因,暗示这些耐盐芽胞杆菌具有不同的耐盐机制。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.