低能钒离子注入花生种子的深度分布

采用鼎瑟福背散射（RBS）和X射线能谱分析法（EDAX）对V元素在花生种子中的深度分布进行了测量,并用扫描电镜对注入前后花生种胚的形貌变化进行观察。结果表明,由于样品表面较粗糙以及其特殊结构,RBS方法不适于测量钒在花生肿胚中的深度分布,trim95也不适合于对注入钒离子在花生种子中的深度进行模拟,而EDAX的测量结果表明V离子的穿透深度可达到15μm。另外,注入前后花生种胚的形貌发生了显著变化。     

MGBG对苜蓿愈作组织生长,体细胞胚胎诱导及其乙烯生物合成的影响

在苜蓿（ＭｅｄｉｃａｇｏｓａｔｉｖａＬ．）愈伤组织继代之初加入不同浓度的甲基乙二醛－双（脒腙）（ＭＧＢＧ）（０．５,１,２ｍｍｏｌ／Ｌ）可不同程度地抑制愈伤组织及其后体胚胎诱导悬浮培养物的生长和体胚形成,若在体胚诱导阶段加入,同上述的抑制作用更为强烈,ＭＧＢＧ不但促进愈伤组织乙烯释放量,内源ＡＣＣ（１－氨基环丙烷－１羧酸）水平和ＡＣＣ合成酶活性,也促进体胚诱导悬浮培养物的ＡＣＣ水平及ＡＣＣ合成酶的     

麦类作物多胚的研究：Ⅲ.高原602双胚苗的细胞学类型

对高原６０２双胚苗的细胞学进行了研究,有３种类型：２ｎ－２ｎ、２ｎ－３ｎ和２ｎ－ｎ,出现频率分别０．１６％、０．０２％和０．０２％,在２ｎ－２ｎ型里,发现了形态上的差异,即２ｎ（顶芒）－２ｎ（长芒）。对单倍体育种和三倍体的起源进行了讨论。     

水分胁迫对芒果(Mangifera indica L.)幼叶细胞活性氧伤害的影响

对芒果进行了水分干旱胁迫处理,结果表明,水分胁迫使芒果幼叶的相对含水量ＲＷＣ（ｒｅｌ－ａｔｉｖｅ ｗａｔｅ ｃｏｎｔｅｎｔ）和叶水势ΨＴ下降,芒果幼叶的超氧离子Ｏ＾－２产生速率随水分胁迫处理强度加大而增加,丙二醛ＭＤＡ（ｍａｌｏｎｄｉａｌｄｅｈｙｄｅ）含量的变化趋势与Ｏ＾－２产生速率的变化趋势相似超氧经歧化酶ＳＯＤ（ｓｕｐｅｒｏｘｉｄｅ ｄｉｓｍｕｔａｃｅ）,这氧化物酶ＰＯＤ（ｐｅｒｏｘｉｄａｓｅ     

氮离子束对小麦种子不同部位作用的突变效应

本文描述了荷能重离子束（^14氮^1 和^14氮^7 ）在作物改良上的应用。为了探讨离子束轰击小麦种子不同部位（例如：种皮,种胚和整粒种籽,包括胚乳、胚和种皮）后的不同反应,采用了不同能量的氮离子。轰击不同部位是通过改变离子能量来实现的。在这个研究中,我们选择了三种能量以达到轰击不同部位的目的,它们是超低能区的110keV,低能区的15．7MeV/u和中能区的72MeV/u.根据TRIM 91程序计算,它们在种子内的射程依次为0．44μm,0.61mm和9.6mm。所以,110keV的离子不能贯穿种皮,因为它的厚度72μm,只能极浅层注入种皮而不能触及胚细胞（称这种情况为轰击部位1）,15．7MeV/u的离子能够贯穿种皮并注入胚内（厚度约1mm),但不能进入胚乳（称这为轰击部位2）,72MeV/u的离子能从种子的胚部到顶部贯穿整个麦粒（麦粒长约7mm)（称这为轰击部位3）。上述三种能量的氮离子辐照了三个品种（定西24、88－12、82－579）的春小麦种子。而后进行了室内实验和大田培育,得到了50％出苗率时的剂量D50,统计了上述三个轰击部位下根尖细胞中的微核率及染色体畸变率,大田中产生了一些新的变异,例如增产（达百分之几十）,早熟（五天左右）,矮杆（低约20cm),抗（条锈）病,并且显示了轰击不同部位的突变频率与突变谱,还简略地讨论了三种情况的突变机理。     

脑室内注入TRH对大鼠肝胆生化影响机理的研究

在大鼠的脑室内注入ＴＲＨ（三肽酰胺）,观察其对大鼠肝胆汁分泌的影响．实验结果表明,侧脑室内注入ＴＲＨ对胆汁分泌量有明显的增强作用,并且随ＴＲＨ剂量加大其作用逐渐增强．而且在侧脑室内注入ＴＲＨ期间,胆汁中Ｋ＋、Ｃｌ－、Ｎａ＋、ＨＣＯ３－离子的排出量亦有增加．其机理在于,侧脑室内注入ＴＲＨ,激活中枢胆碱能系统,并通过送走神经而使肝的新陈代谢发生变化．     

普通小麦—鹅观草异附加系的选育与鉴定初报

应用根尖细胞染色体计数、花粉母细胞减数分裂染色体配对构型分析、植株外形特征观察、染色体Ｃ－分带技术,在普通小麦（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ Ｌ．）－鹅观草（Ｒｏｅｇｎｅｒｉａ ｋａｍ ｏｊｉＯｈｗ ｉ）的杂交及回交后代Ｆ５、ＢＣ１Ｆ３、ＢＣ１Ｆ４和ＢＣ２Ｆ４群体中选育并鉴定出３个二体异附加系Ｖ３９－１５－５、Ｖ３５－８－８ 和Ｖ５８－６－１１。对植株外形特征观察法和Ｃ－分带技术在普通小麦－鹅观草异附加系的选育和鉴定过程中的作用等问题进行了讨论     

在离体条件下拐芹（Angelica polymorpha）形成胚性愈伤组织和非…

以拐芹（Ａｎｇｅｌｉｃａ ｐｌｏｙｍｏｒｐｈａ）的叶柄为外植体,在附加２,４－Ｄ（１ｍｇ／Ｌ）＋ＫＴ（０．５ｍｇ／Ｌ）ＭＳ培养基上诱导脱分化,４０天内可形成愈伤组织。在相同的培养基上经过继代培养,可在２０天内形成胚性愈伤组织（Ｅｍｂｒｙｏｇｅｎｉｃ Ｃａｌｌｕｓ,ＥＣ）和非胚性愈伤组织（Ｎｏｎ－Ｅｍｂｒｙ－ｏｇｅｎｉｃ Ｃａｌｌｕｓ,ＮＥＣ）。将不同天数的培养物作为样品,提取其内源激素;气液相色谱     

昆明白小鼠1细胞胚胎体外培养系统的研究

研究发现在有或者没有磷酸盐的条件下,葡萄糖均抑制昆明白小鼠ｌ－４细胞期胚胎的体外发 育。在不含葡萄糖和磷酸盐的ＨＥＣＭ－ｌ中,桑椹率为４０．０５％（７４／１６８）,而对照Ｇ－ＨＥＣＭ－１仅为 ８．１４％（７／８６）;不含葡萄糖含有磷酸盐的ＣＺＢ中,桑椹率为６７．１１％（９３／１５２）,而对照ＴＡＬＰ仅 ６· ６７％（６／９０）。用不含葡萄糖而含有１． ０ｍｍｏ１／Ｌ谷氨酸肢和０． １１ｍｍｏｌ／Ｌ ＥＤＴＡ的ＣＺＢ液,与兔输 卵管上皮单层培养细胞（ＲＯＥＣ）协同培养小鼠１细胞胚,７３．３３％（１１０／１５０）胚胎发育至桑椹胚, 但没有观察到囊胚形成、用上述ＣＺＨＲＯＥＣ系统培养小鼠１细胞胚４８小时（３－４细胞）,再移入 ＴＣＭ１９９＋１０％ＦＣＳ＋ＲＯＥＣ系统,有７６．７４％（６７／８６）胚胎发育至桑椹胚,９６／小时后,４０．７０％ （３５／８６）发育至囊胚。     

L－异亮氨酸产生菌选育的研究

以黄色短杆菌（Ｂｒｅｖｉｂａｃｔｅｒｉｕｍｆｌａｖｕｍ）ＡＴＣＣ１４０６７为出发菌株,经硫酸二乙酯（ＤＥＳ）、紫外线（ＵＶ）和亚硝基胍（ＮＴＧ）逐级诱变处理,α－氨基－β－羟基戊酸（ＡＨＶ）、Ｓ－２－氨基乙基－Ｌ－半胱氨酸（ＡＥＣ）、磺胺胍（ＳＧ）、乙硫氨酸（Ｅｔｈ）、α－氨基丁酸（α－ＡＢ）、异亮氨酸氧肟酸（ＩｌｅＨｘ）等氨基酸结构类似物及琥珀酸为碳源平板定向筛选,获得一株Ｌ－异亮氨酸高产菌ＺＱ－４（ＡＨＶ~γ、ＡＥＣ~γ、ＳＡＭ~γ、ＳＧ~γ、Ｅｔｈ~γ、α－ＡＢ~γ、ＩｌｅＨｘ~γ）在含１３．５％葡萄糖培养基中,摇瓶发酵７２ｈ、Ｌ－异亮氨酸积累可达２．８－３．０％。     

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