一粒小麦×野燕麦衍生系细胞学特征及条锈病抗性鉴定

在一粒小麦与葡萄牙野燕麦远缘杂交后代中,选育了5个形态学稳定的抗条锈病衍生系(‘一粒葡’)YLP-1、YLP-7、YLP-9、YLP-13和YLP-16,为筛选含有外源染色体且抗性优良的植株,对该衍生系的细胞学特征和抗病性进行了鉴定。细胞学初步鉴定表明:根尖染色体数目均为2n=42,花粉母细胞减数分裂中期Ⅰ染色体构型为2n=21Ⅱ;5个选系与‘中国春’杂交F1花粉母细胞减数分裂中期Ⅰ的异常细胞构型率为16%～50%;初步鉴定这5个‘一粒葡’材料均为易位系,验证了‘一粒葡’是远缘杂交的后代。用9个条锈菌小种分别对9个株系进行苗期抗病性鉴定,有5个株系YLP-1-4、YLP-7、YLP-9-1、YLP-9-3、YLP-16-1对所有参试小种都表现为高抗,且与已知的Yr5、Yr10、Yr15、Yr24/Yr26基因不同,表明‘一粒葡’中可能含有新的抗病基因,可作为抗源用于小麦抗病育种。     

用基因组原位杂交与RFLP标记鉴定小麦——簇毛麦抗白粉病代换系

用荧光素标记的簇毛麦(Haynaldia villosa)基因组总DNA作探针,以普通小麦基因组总DNA作封阻,与花粉母细胞减数分裂中期Ⅰ制片的染色体进行原位杂交。结果表明,抗白粉病小麦品系GN22是普通小麦-簇毛麦二体代换系;用已定位在小麦第6部分同源群上的RFLP探针psr113、psr371进行Southern分析,进一步证明,小麦品系GN21、GN22是普通小麦-簇毛麦6A(6V)代换系;结合同工酶等电聚焦电泳分析,首次把簇毛麦编码的α-淀粉酶-1生化位点定位在簇毛麦6V染色体长臂上,暂命名为α-Amy-Ⅴ1。研究结果表明,原位杂交与RFLP技术相结合是全面、准确鉴定小麦外源染色体及其与小麦染色体部分同源关系的有效方法。     

应用基因组原位杂交及RFLP标记鉴定小麦中的大麦染色体

用生物素（Biotin-6-dUTP)标记的大麦Betzes基因组DNA作探针,以普通小麦中国春总DNA作封阻进行基因组原位杂交（Genomeinsituhybridization,简称GISH）,从13株小麦-大麦杂交后代中鉴定出2个含有3条大麦Betzes2H染色体的材料（2n＝43）;2个2H单体异代换系（2n＝42）;7个2H二体异代换系（2n＝42）。用已定位在小麦第2部分同源群短臂上的探针psr131进行RFLP分析,结果表明大麦Betzes、代换系A5有1条区别于小麦中国春的特异带,A     

提莫菲维小麦与光稃野燕麦远缘杂交后代花粉母细胞减数分裂行为分析

通过普通细胞学和基因组原位杂交(GISH)研究提莫菲维小麦(Triticum timopheevi)与光稃野燕麦(Avena fatua L.var.glabrata Pat)远缘杂交后代花粉母细胞染色体减数分裂行为.结果表明,该R株系花粉母细胞的减数分裂指数为87.46,表现出一定的遗传不稳定性.GISH分析发现该F3株系中期I细胞中有4对红色杂交信号,且游离的单价体上各有1个杂交信号;后期Ⅰ、后期Ⅱ和末期Ⅱ出现落后染色体、染色体桥、微核等现象,分别占观察数的10.58％、1.92％和12.36％,这些异常现象可能是由于光稃野燕麦遗传物质干扰了小麦同源染色体或部分同源染色体的正常配对造成的.     

小麦及远缘杂交后代苗期耐盐性综合评价

对121份小麦等材料的耐盐性进行综合评价,以期为小麦耐盐生理、遗传育种等研究提供参考。结果表明,根据耐盐性将供试材料分为5类:高耐盐材料(P13、C1009、1710、1713和082-1,D值0.5877～0.6616);耐盐材料(1706、081、0819-1、PSR3628和TB1等9份种质,D值0.4222～0.5331);中耐盐材料(1707、1805、TPF8、1704和1712等41份种质,D值0.2684～0.3940);盐敏感材料(45份种质,D值0.1922～0.2640);高盐敏感材料(21份种质,D值0.0504～0.1848)。偏凸山羊草×硬粒小麦衍生系中P13、082-1、081、082-2材料的D值分布在0.4231～0.6616之间,表现为高耐或耐盐。一粒小麦×葡萄牙野燕麦衍生系,提莫菲维小麦×葡萄牙野燕麦衍生系的D值均值分别为0.4145和0.4106,显著大于普通小麦群体,它们总体上表现耐盐。8个小麦远缘杂交后代群体D值均值大于普通小麦群体,筛选出P13、1713、082-1、1706和081等耐盐新种质。     

栽培稻与疣粒野生稻杂种F1代的基因组原位杂交鉴定

生物素标记的疣粒野生稻总DNA作探针,未标记的栽培稻总DNA封阻,对栽培稻与疣粒野生稻杂种F1体细胞染色体进行基因组原位杂交（Genomic in situ hybridization,简称GISH）分析。FITC检测表明,杂种细胞中来自瘛发粒野生稻的染色体有较多的黄色或黄绿色荧光信号,来自栽培稻的染色体只检出很少的信号。每条疣粒野生稻染色体上信号点所占的总的区域只是染色体的一小部分,表明疣粒野生稻染色体与栽培稻染色体的DNA序列大部分是同源的。     

麦类作物体细胞基因组原位杂交(GISH)效果影响因素的分析

以八倍体小滨麦、八倍体小黑麦、八倍体小偃麦、小麦-中间偃麦草双体异附加系为实验材料对影响麦类作物体细胞GISH技术实验效果的因素进行分析,研究结果表明:细胞分裂相多、染色体分散良好、无杂质影响的高质量的染色体制片是取得理想实验效果的基础;探针DNA浓度与封阻DNA浓度的比例及杂交后洗脱条件的控制是取得理想实验效果的关键。此外,还对麦类作物体细胞基因组原位杂交实验中出现的染色体丢失、外源染色体无杂交信号、杂交信号的强弱、杂交信号过多(杂交背景重)或过少、噪音信号及杂交污点产生的原因进行了分析,并提出了相应的解决方法或注意事项。     

基因组原位杂交鉴定牛筋草AA基因组在穇子染色体上的分布及探针长度优化方法

采用基因组原位杂交(Genomic in situ hybridization,GISH)方法研究了牛筋草(Eleusine indica)AA基因组在穇子(E.coracana)染色体上的分布,并探讨了AA、BB基因组的同源关系。用超声波破碎法进行预剪切,以缺口平移法标记的牛筋草总DNA为探针,BB基因组的E.floccifolia(Forssk.)Spreng.总DNA为封阻,与AABB基因组穇子的中期染色体进行杂交。结果表明,牛筋草AA基因组分布在穇子的18条染色体上。不加封阻或加过量封阻均不能鉴别AA基因组,说明AA和BB基因组间的分化程度不大,双方共享的重复序列较多。牛筋草与E.floccifolia总DNA分别用超声波破碎2 min和3 min后,可得到峰值为300-750 bp的DNA片段,这说明不同物种的超声波破碎时间需要调整,以获得合适长度的探针。     

麦类作物体细胞基因组原位杂交（GISH）效果影响因素的分析

以八倍体小滨麦、八倍体小黑麦、八倍体小偃麦、小麦一中间偃麦草双体异附加系为实验材料对影响麦类作物体细胞GISH技术实验效果的因素进行分析,研究结果表明：细胞分裂相多、染色体分散良好、无杂质影响的高质量的染色体制片是取得理想实验效果的基础;探针DNA浓度与封阻DNA浓度的比例及杂交后洗脱条件的控制是取得理想实验效果的关键。此外,还对麦类作物体细胞基因组原位杂交实验中出现的染色体丢失、外源染色体无杂交信号、杂交信号的强弱、杂交信号过多(杂交背景重)或过少、噪音信号及杂交污点产生的原因进行了分析,并提出了相应的解决方法或注意事项。     

柑橘基因组原位杂交(GISH)技术体系的建立

通过改进实验方法,建立起柑橘基因组原位杂交(Genomic in situ hybridization,GISH)分析技术,并成功地应用于属间有性杂种鉴定,为进一步分析柑橘体细胞杂种核基因组组成奠定了基础。柑橘的染色体制片以去壁低渗-火焰干燥法较好,容易获得大量清晰、分散的有丝分裂中期相,且杂质较少。切刻平移法生物素(Biotin)标记探针,标记基因组总DNA与封阻基因组总DNA的浓度比例为1：50时,能有效分开属间杂种枳橙中来自双亲的染色体。     

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.     

鸡传染性法氏囊病病毒研究进展

传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.     

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.     

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).     

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.