棉铃虫核型多角体病毒Hind III-K片段的核苷酸序列及其分析

测定了棉铃虫（Ｈｅｌｉｃｏｖｅｒｐａａｒｍｉｇｅｒａ）核型多角体病毒（ＨａＳＮＰＶ）基因组ＤＮＡ的ＨｉｎｄＩＩＫ片段核苷酸序列。该片段全长３２５５ｂｐ,含可编码大于４０个氨基酸残基的多肽的开放阅读框（ＯＲＦ）１５个,包括多角体蛋白（ｐｈ）基因编码区３′端４８９ｂｐ和蛋白激酶ＨａｖＰＫ基因编码区８０１ｂｐ。在ｐｈ和ＨａｖＰＫ两基因之间鉴定出一个可编码４１２个氨基酸残基的ＯＲＦ１２３６,转录方向与ｐｈ和ＨａｖＰＫ基因相反。同源分析表明,ＯＲＦ１２３６与谷实夜蛾（Ｈｅｌｉｃｏｖｅｒｐａｚｅａ）核型多角体病毒（ＨｚＳＮＰＶ）的ＯＲＦ８推导的蛋白氨基酸序列有９５．９％同源性,与苜蓿丫纹夜蛾（Ａｕｔｏｇｒａｐｈａｃａｌｉｆｏｒｎｉａ）核型多角体病毒（ＡｃＭＮＰＶ）ＯＲＦ１６２９只有２４．８％同源性,但三者均含有二组由多个脯氨酸残基串联而成的特征基序。     

中国棉铃虫核型多角体病毒不同基因型的虫体克隆

首次利用虫体克隆技术,对野生型中国棉铃虫核型多角体病毒（ＨａＳＮＰＶＷ）的不同基因型进行了分离纯化。以较低浓度的ＨａＳＮＰＶＷ感染三龄初中国棉铃虫幼虫,病毒致死幼虫单虫收集,分别提取相应的病毒核酸,进行限制性内切酶分析,得到了ＨａＳＮＰＶ的七个不同基因型（ＨａＳＮＰＶＧ１至Ｇ７）,其ＥｃｏＲＩ酶切图谱均不相同。用ＢａｍＨＩ酶切分析,七个基因型的酶切图谱只在一个片段上有显著区别：Ｇ１、Ｇ２、Ｇ３、Ｇ４ＤＮＡ的ＢａｍＨＩｈ片段大小是３．３０ｋｂ,Ｇ５、Ｇ６的这一片段的大小为３．５ｋｂ,而Ｇ７的这一片段为２．７ｋｂ。结果表明,野生型ＨａＳＮＰＶ至少包含七个不同的基因型。     

棉铃虫（Heliothisspp）核型多角体病毒四个分离株的比较研究

本文从形态结构、生物活性、结构多肽、核酸限制性内切酶图谱和核酸同源性等方面对棉铃虫核型多角体病毒四个分离株（两个ＳＮＰＶ分离株：ＨａＳ、ＨｚＳ,和两个ＭＮＰＶ分离株：ＨａＭ１、ＨａＭ２）进行了比较研究。它们对中国棉铃虫二龄末三龄初幼虫的ＬＤ５０佰依次为３６１、３８７、２６３３、３５６０ＰＩＢｓ／克饲料,当感染剂过为５×ｌ０３ＰＩＢｓ／克饲料时,其ＬＴ５０值依次为４．６、４．９、６．４和６．６天。两个ＳＮＰＶ分离株的生物活性显著高于两个ＭＮＰＶ分离株。经ＳＤＳ－ＰＡＧＥ分析,四个分离株多角体蛋白均为一条带,两个ＭＮＰＶ分离株结构多肽均具有相同的迁移率,两个ＳＮＰＶ分离株的结构多肽图谱也颇相似,但ＳＮＰＶ与ＭＮＰＶ分离株之间带型相差较大。各分离株基出组经ＢａｍＨＩ、ＥｃｏＲＩ、ＨｉｎｄⅢ和ＸｂａＩ消化后,得到的内切酶图谱表现为两个ＮＭＰＶ分离株一致,两个ＳＮＰＶ分离株也很相似,而ＳＮＰＶ与ＭＮＰＶ分离株之间相差很大。严格条件杂交结果表明：两个ＳＮＰＶ分离株的基因组有较高的同源性,而ＳＮＰＶ与ＭＮＰＶ基因组之间的同源性极低。     

家蚕核型多角体病毒egt基因的结构和功能分析

以苜宿银纹夜蛾核型多角体病毒（ＡｃＭＮＰＶ）的ｅｇｔ基因作探针,从家蚕核型多角体病毒镇江株（ＢｍＮＰＶ ＺＪ－８）基因组中克隆了ｅｇｔ基因及其旁侧序列,作了该片段的酶切图谱;测定了ＢｍＮＰＶ ＺＪ－８ｅｇｔ基因序列。与ＡｃＭＮＰＶ的ｅｇｔ基因相比同源性为９５％;基因大小都为１５１８ｂｐ。利用ｅｇｔ基因旁侧序列构建了转移载体ｐＵＤｅｇｔ,以绿色荧色光蛋白基因（ＥＧＦＰ）作报告基因取代ｅｇｔ基因,构建     

茶尺蠖核型多角体病毒多角体蛋白基因核苷酸序列及其在Baculoviridae中的地位(英文)

茶尺蠖核型多角体病毒（ＥｏＳＮＰＶ）基因组的ｐｏｌｈ和ｅｇｔ基因区约１４．２ｋｂ的酶切图谱被构建．ｅｇｔ基因位于ｐｏｌｈ基因上游约４．８ｋｂ处,但转录方向与ｐｏｌｈ基因相反．ＥｃｏＲⅤ－Ｌ片段ｐｏｌｈ基因及其旁侧的１１２５核苷酸序列被测定．ｐｏｌｈ基因编码区长７３８核苷酸,可编码２４６氨基酸的多肽．起始密码子ＡＴＧ上游是一个富含ＡＴ（ＡＴ占７１．２％）的启动子区,在－５２核苷酸处有杆状病毒晚期基因启动子转录起始基序ＡＴＡＡＧ．在终止密码子下游２０８核苷酸有一个ｐｏｌｙ（Ａ）信号,ＡＡＴＡＡＡ．但ＥｏＳＮＰＶｐｏｌｈ基因起始密码子ＡＴＧ相邻核苷酸序列为ＧＴＡＡＴＧＴ,其－３是个Ｇ,这与已知的１６种其它杆状病毒ｐｏｌｈ基因－３位置均是Ａ不相同．在分析了ＥｏＳＮＰＶ和ＨａＳＮＰＶ多角体蛋白基因核苷酸序列的基础上,通过ＭＡＬＩＧＮ程序,比较了目前已发表的２６种杆状病毒包涵体蛋白的序列,ＥｏＳＮＰＶ与黄杉毒蛾核型多角体病毒（ＯｐＳＮＰＶ）的同源性为最高,核苷酸序列的同源性为８３．０％,氨基酸序列达９４．７％;与其它２０种鳞翅目ＮＰＶ的同源性也很高,核苷酸序列同源性为７２．６％～８１．９％,氨基酸序列为８３．７％～９３     

粘虫核型多角体病毒多角体蛋白基因结构和序列的研究

测定了粘虫核型多角体病毒（Ｌｅｕｃａｎｉａｓｅｐａｒａｔａｎｕｃｌｅａｒｐｏｌｙｈｅｄｒｏｓｉｓｖｉｒｕｓ,ＬｓＮＰＶ）两个ＥｃｏＲＶ片段的共１２０１ｂｐ序列,发现了一个７１４ｂｐ的开放阅读框（ＯＲＦ）,根据其与多种ＮＰＶ多角体蛋白基因（ｏｃｕ）同源性的比较和５＇端典型的１４ｂｐ保守序列,说明此ＯＲＦ即为ＬｓＮＰＶ的ｏｃｕ基因。根据核苷酸序列预测的多角体蛋白有２４６个氨基酸,其中酸性和碱性氨基酸数相等,疏水氨基酸含量很高,氨基酸组成中以谷氨酸（Ｇｌｕ）含量最高,谷氨酰胺和半胱氨酸含量最低。编码区碱基同源性与ＭｂＮＰＶ最高,为９７．０％;氨基酸同源性与ＭｂＮＰＶ最高,为９７．５％。密码子偏爱选用以第三个碱基为嘧啶的密码子。二级结构分析表明,α－螺旋（Ｈ）和β－折叠（Ｓ）相等,β－转角含量是Ｈ和Ｓ含量之和。     

棉铃虫核型多角体病毒p35基因的PCR扩增和克隆及其在原核细胞中的表达

用苜蓿银纹夜蛾核型多角体病毒（ Ａｃ Ｎ Ｐ Ｖ） 凋亡抑制基因ｐ３５ 的合成引物,从棉铃虫核型多角体病毒（ Ｈａ Ｎ Ｐ Ｖ） 基因组中用 Ｐ Ｃ Ｒ 扩增到了１ｋｂ 片段。采用 Ｐ Ｃ Ｒ－ 双脱氧核苷酸链终止银染法,测定了所扩增到的１ ０１０ｂｐ 全序列,发现其开放阅读框完整,长８９７ｂｐ ,编码２９９ 个氨基酸。用 Ｄ Ｎ Ａ Ｓ Ｉ Ｓ 和 Ｐ Ｒ Ｏ Ｓ Ｉ Ｓ 软件分析发现,此片段与 Ａｃ Ｍ Ｎ Ｐ Ｖ ｐ３５ 基因同源区核苷酸同源性为９１ ％ ,氨基酸同源性也达８１ ％ ,证明了所扩增的片段是 Ｈａ Ｎ Ｐ Ｖ 的ｐ３５ 基因。为了研究此ｐ３５ 基因的功能及其效应机制,克隆了这一基因并在大肠杆菌细胞中实现了表达。     

苜蓿丫纹夜蛾核型多角体病毒(AcMNPV)大立方形多角体突变株的分子生物学研究

利用空斑技术,从既能形成多角体又含ＴＫ酶基因的苜蓿丫纹夜蛾重组核型多角体病毒ＡｃＭＮＰＶ－ＴＫ中,纯化了一株形成大立方形多角体的病毒突变株ＡｃＭＮＰＶ－ＴＫｍｔ５１３。用ＥｃｏＲＩ、ＰｓｔⅠ、ＢｇｌⅡ及ＫｐｎⅠ等限制性内切酶对它做了酶切分析,并克隆了多角体蛋白全基因及其侧翼部分的片段。对所克隆的部分全序列测定结果,发现在多角体蛋白基因读码框内只出现了一个碱基的突变,导致了第２５位的氨基酸密码子由ＧＧＴ变为ＧＡＴ,该位氨基酸由甘氨酸（Ｇｌｙ）变为天冬氨酸（Ａｓｐｑ）还利用ＰＣＲ技术扩增出突变了的多角体蛋白基因部分片段,并将它克隆入转移载体质粒ｐＥＶ５５,与不形成多角体的重组病毒ＴｎＮＰＶ－ＨＢｓＤ４ＤＮＡ共转染Ｓｆ９细胞,结果产生同样的大立方形多角体病毒。     

中国棉铃虫核型多角体病毒几丁质酶基因的定位与克隆

以α３２ＰｄＡＴＰ标记含ＣｆＭＮＰＶ几丁质酶基因的重组质粒为探针,在６８℃条件下对棉铃虫单粒包埋核型多角体病毒（ＨａＳＮＰＶ）进行Ｓｏｕｔｈｅｒｎ杂交,将ＨａＳＮＰＶ的几丁质酶基因分别定位在ＢａｍＨＩＥ、ＢｇｌⅡＥ、ＥｃｏＲＩＧ、ＨｉｎｄⅢＦ、ＸｂａＩＨ、ＢａｍＨＩ＋ＨｉｎｄＩＩＭ和ＢａｍＨＩ＋ＸｂａＩＨ,并以ｐＴＺ１９Ｒ为载体获得了ＸｂａＩＨ片段克隆。     

家蚕NPV SOD基因序列和在大肠杆菌中表达

通过ＰＣＲ 克隆了家蚕核型多角体病毒（ＢｍＮＰＶ） ＳＯＤ基因, 并在大肠杆菌中进行表达, 证明了Ｂｍ ＮＰＶＳＯＤ基因产物确有ＳＯＤ活性, 其活力单位约为５７６ ｕ／ｍＬ 培养液。ＤＮＡ 测序结果表明Ｂｍ ＮＰＶ ＳＯＤ 基因编码１５１ 个氨基酸, 与人的ＳＯＤ１ 基因的核苷酸同源性为５６ ％ , 与ＡｃＮＰＶ 拟为的ＳＯＤ基因同源性为９７ ．２％ 。     

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.     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.     

Composition and diversity of bird communities in Swedish farmland–forest mosaic landscapes

CapsuleThe amount of forest (at local and landscape scales) and occurrence of residual habitats at the local scale are shown to be the major factors influencing bird community composition in farmland–forest landscapes in central Sweden.

Aims To investigate the importance of local habitat and landscape structure for breeding birds in farmland–forest landscapes in central Sweden.

Methods Breeding birds were censused at 292 points. A detailed habitat mapping was made within 300 m of the points. Within a 300–600 m radius only two major habitats (forests and arable fields) were identified.

Results Cluster analyses of bird communities identified three site types that also differed in habitat composition: (i) partially forested sites in forested landscapes; (ii) heterogeneous sites with residual habitats in mosaic landscapes; and (iii) field-dominated farmland sites in open landscapes. A total of 19 of 25 farmland bird species (restricted to farmland or using both farmland and forest) had the highest abundance in farmland sites with mosaics of forest and farmland, while only six farmland species had the highest abundance in field-dominated sites. The bird community changed from being dominated by farmland species to being dominated by forest species (common in forest landscapes without farmland) at small proportions (10–20%) of forest at the local scale. A major difference in habitat composition between heterogeneous and field-dominated sites was the occurrence of different residual habitats (e.g. shrubby areas and seminatural grasslands). These habitats seemed to influence bird community composition more than land-use, despite covering <10% of the area. Seminatural grasslands were important for bird community composition and species-richness, but grazing seemed to be less important. Among different land-use types, cereal crops were the least preferred fields. Set-asides with tall vegetation and short rotation coppices were positively associated with species-richness of farmland birds.

Conclusion In general, the composition of the landscape was important for bird community composition, although amount and distribution of forests, occurrence of residual habitats and land-use of fields at the local scale had the strongest influence on bird community composition. The possible implications of these patterns for managing farmland–forest landscapes are discussed.     

Chemical constituents from the fruits of Rhus typhina L. and their chemotaxonomic significance

This work describes the isolation and characterization of twenty-nine compounds from the fruits of Rhus typhina L., including eleven flavonoids (1–11), eleven phenols (12–22), two pentacyclic triterpenes (23–24), two organic acids (25–26), one lumichrome (27), one courmarin (28) and one pyrimidine (29) on the basis of their spectroscopic data. Compounds apigenin (1), daidzein (4), orobol (5), 3′, 5, 5′, 7-tetrahydroxyflavanone (6), naringenin (7), butein (8), (-)-catechin (9), quercetin-3-O-α-L-(3″-O-galloyl)-rhamnoside (11), 2-hydroxybenzoic acid (13), 4-hydroxybenzaldehyde (14), vanillin (15), methyl 3,4-dihydroxybenzoate (16), 3,5-dihydroxybenzamide (18), tyrosol (19), caffeic acid (20), 3-(2,4,6-trihydroxyphenyl)-1-(4-hydroxyphenyl)-propan-1-one (21), phlorizin (22), friedelin (23), oleanolic acid (24), 4,4-dimethyl-heptanedioic acid (25), anthranilic acid (26), lumichrome (27), scoparone (28) and uracil (29) have not been recorded before in this plant. This is the first report on the occurrence of compounds 4–7, 9, 11, 13–14, 16, 18–21, 25–29 from the genus Rhus. Moreover, the chemotaxonomic significance of these isolated compounds was also summarized.