葱属合被组植物的引种栽培及染色体观察

对国产葱属合被组（ＡｌｌｉｕｍＳｅｃｔ．Ｃａｌｏｓｃｏｒｄｕｍ）的长梗韭（Ａ．ｎｅｒｉｎｉｆｌｏｒｕｍ）和合被韭（Ａ．ｔｕｂｉｆｌｏｒｕｍ）进行了引种栽培实验及染色体观察,结果表明：将原野生状态下生长的这２个种转为人工条件下栽培,长势良好,能正常开花结实;体细胞染色体数显示,长梗韭四个居群均为二倍体２ｎ＝２ｘ＝１６,合被韭的一个居群为二倍体２ｎ＝２ｘ＝１６,另一个居群为四倍体２ｎ＝４ｘ＝３２,所不同的是长梗韭染色体带有一对中间随体,而合被韭染色体则带有一对或二对末端随体。此外,首次发现合被韭存在有二次生长现象。     

脐橙与柠檬种间细胞电融合再生杂种植株

‘纽荷尔’脐橙（Ｃｉｔｒｕｓｓｉｎｅｎｓｉｓ（Ｌ．）Ｏｓｂｅｃｋ）胚性细胞悬浮原生质体与‘尤力克’柠檬（Ｃｉｔｒｕｓｌｉｍｏｎ（Ｌ．）Ｂｕｒｍ．ｆ）叶肉原生质体经电场诱导融合,培养８个月,首批再生了１棵植株,形态学观察,染色体计数及ＲＡＰＤ分析证明异源四倍体体细胞杂种,该杂种的获得为三倍体无籽柠檬品种培育提供了杂交亲本。     

柑橘细胞电融合参数选择及种间体细胞杂种植株再生

以“Ｐａｇｅ”橘柚（ＣｉｔｒｕｓｒｅｔｉｃｕｌａｔａＢｌａｎｃｏ×Ｃ．ｐａｒａｄｉｓｉＭａｃｆ）胚性悬浮系原生质体和粗柠檬（Ｃ．ｊａｍｂｈｉｒｉＬｕｓｈ）叶肉原生质体为融合试材,摸索了适合柑橘的电融合参数。研究表明,在ＡＣ（交变电场）１２５Ｖ／ｃｍ、ＤＣ（直流脉冲）１２５０Ｖ／ｃｍ、ＡＣ作用时间６０ｓ、ＤＣ脉冲时间５０μｓ、ＤＣ脉冲个数为３、ＤＣ脉冲间隔为０．５ｓ时融合率较高,双核异核体率可以达到１５％以上。利用不同类型原生质体比重的不同,融合后通过控制离心时间,可以收集到更高比例的双核异核体。融合产物经培养,３～４个月再生小植株。染色体计数结合形态学观察表明,再生的１５０株小植株中７８％为四倍体,其余为二倍体叶肉亲本再生类型。再生植株经过氧化物酶同工酶及ＲＡＰＤ分析,表明得到了体细胞杂种,还证明获得了１株叶肉亲本同源四倍体再生类型。     

单倍体小麦与羊草的属间体细胞杂交

以失去植株再生能力的小麦单倍体愈伤组织和羊草二倍体愈伤组织为材料,游离原生质体,并用紫外线自理２羊草原生质体,用ＰＥＧ法融合,对融合克隆进行染色体和同工酶分析,在已贩２６个克隆中有２１个是杂种,其中有一个克隆再生出短命小植株,结果 体小麦与二倍体草的不对称融合虽然再生互补效应不如二倍体小麦,然而杂种优先生长的现象仍然比较明显。如果改善实验条件和双亲原始的再生能力,这种融合方式仍然可以利用。     

THINOPYRUM BESSARABICUM和THINOPYRUM ELONGATUM的基 …

对２个八倍体Ｃ．Ｓ－Ｔｈｉｎｏｐｙｒｕｍ ｂｅｓｓａｒａｂｉｃｕｍ（ＡＡＢＢＤＤＪＪ,２ｎ＝８ｘ＝５６）和Ｇｏｓｈａｗｋ（ＧＨＫ）－Ｔｈｉｎｏｐｙｒｕｍ ｅｌｏｎｇａｔｕｍ（ＡＡＢＢＤＤＥＥ,２ｎ＝８ｘ＝５６）的根尖细胞染色体进行Ｃ－分带,从中分检出Ｔｈ．ｂｅｓｓａｒａｂｉｃｕｍ和Ｔｈ．ｅｌｏｎｇａｔｕｍ的各自染色体进行核型分析,结果表明：Ｔｈ．ｂｅｓｓａｒａｂｉｃｕｍ和Ｔｈ．ｅｌｏｎｇａｔｕｍ的     

柑桔原生质体辐射诱变筛选抗寒再生植株

用１１６１Ｃ／ｋｇ软Ｘ射线辐射“Ｐａｇｅ”桔柚（ＣｉｔｒｕｓｒｅｔｉｃｕｌａｔａＢｌａｎｃｏ×Ｃ．ｇｒａｎｄｉｓＯｓｂ．ｃｖ．Ｐａｇｅ）胚性愈伤组织分离的原生质体,经－１１℃低温选择后,将存活的原生质体培养再生植株。研究表明,“Ｐａｇｅ”桔柚胚性愈伤组织原生质体在４１２８Ｃ／ｋｇ辐射剂量处理后几乎不能恢复分裂;２０６４Ｃ／ｋｇ辐射时分裂频率低,即使分裂也难以发育为胚状体;而１１６１Ｃ／ｋｇ辐射后,经－１１℃低温处理仍有１０２％～１６９％的分裂频率,且部分细胞团能发育为胚状体。辐射的原生质体培养成胚状体后,经低温筛选,在改良的生芽培养基和生根培养基中萌发成为植株。再生植株中检测出２株的叶片原生质体的低温半致死温度（ＬＴ５０）分别比对照低１．９６℃和１６８℃。     

小麦与高冰草属间体细胞杂交获可育杂种植株

普通小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．２ｎ＝４２）“济南１７７”与紫外线照射的高冰草（长穗偃麦草Ａｇｒｏｐｙｒｏｎｅｌｏｎｇａｔｕｍ,２ｎ＝７０）原生质体在ＰＥＧ诱导下融合,获杂种再生植株。取杂种子房诱导产生愈伤组织并再生植株,经染色体和同工酶鉴定,它们仍保留杂种性质。其中两株移栽成活并结实,杂种性质也经表型、染色体、同工酶和ＲＡＰＤ分析得到证明。在Ｆ０和Ｆ１代植株根尖细胞中,均发现高频率地存在着染色体断片;从Ｆ２代花粉母细胞减数分裂的染色体数目及行为发现,杂种细胞染色体数目主要分布在１８Ⅱ～２２Ⅱ,染色体断片发生配对及分离,表明它们是小染色体（ｍｉｎｉｃｈｒｏｍｏｓｏｍｅｓ）。Ｆ１及Ｆ２代植株比亲本小麦（“济南１７７”）秆茎粗硬、生长健壮,穗大粒大,已经产生具有优良性状的Ｆ２代穗系     

影响火炬松胚性悬浮细胞原生质体的胚胎发生的因素(英文)

火炬松（ＰｉｎｕｓｔａｅｄａＬ．）是我国亚热带和部分热带地区最重要的绿化和造林树种。它的生长周期长,杂合程度高,难以用常规的杂交方法进行品种改良。建立火炬松的原生质体胚胎发生体系,有可能、进而以遗传转化为基础进行火炬松等针叶树的品种改良。本研究以湖南省绍阳市的火炬松成熟种子为材料,建立胚性细胞悬浮系。将其培养至对数生长期,用１％ＲＳ、２．５％Ｒ１０和０．２％Ｙ２３的酶混和液分离原生质体,活力达９０％以上（Ｆｉｇ．１）。纯化原生质体,在再生培养基上培养２天后,细胞壁再生（Ｆｉｇ．２）;;６天后,６５％的原生质体第１次分裂（Ｆｉｇ．３）;培养３周后,形成小细胞团（Ｆｉｇ．４）;６周后,形成大细胞团（Ｆｉｇ．５）;８周后,形成胚性胚柄细胞团（ＥＳＭ）（Ｆｉｇ．６）;１０周后,形成早期体细胞胚（ＥＳＥ）（Ｆｉｇ．７）;１２周后,形成后期体细胞胚（ＬＳＥ）（Ｆｉｇ．８）火炬松原生质体胚形成过程中的关键结构是ＥＳＭ,ＥＳＥ和ＬＳＥ。它们形成的最佳基本培养基是１．２５ＬＰ培养基。再生培养基中高浓度的ＢＡ和低浓度的肌醇有利于ＥＳＭ的形成,但不利于ＥＳＥ和ＬＳＥ的形成。反之,低浓度的ＢＡ和高浓度的肌醇不利于ＥＳＭ的形成,     

宜昌橙与伏令夏橙种间体细胞杂种

宜昌橙(Citrus ichangensis SwingIe)试管实生苗叶肉原生质体与伏令夏甜橙(C．Sin-ensis Osbeck)胚性悬浮细胞系原生质体,经聚乙二醇(PEG)诱导融合。再生出的胚状体为畸形,转移到生芽培养基中诱导产生丛芽。丛芽微嫁接在15天龄的枳壳砧上成为完整植株。幼叶染色体检查表明,两亲本均为二倍体2n=2x=18,融合后再生出的植株为四倍体2n=4x=36。过氧化物酶(POX)及谷草酰胺转氨酶(GOT)同工酶分析证明,这些四倍体均为体细胞杂种,它们同时含有双亲的酶带。杂种植株叶片形态更像甜橙。植株移八土壤后生长旺盛。     

水稻PDER品系的特点和二倍体孢子生殖胚囊的形成和发育

对水稻（ＯｒｙｚａｓａｔｉｖａＬ．）早发生胚ＰＤＥＲ（ｐｒｅ－ｄｅｖｅｌｏｐｅｄｅｍｂｒｙｏｏｆｒｉｃｅ）品系的特点和细胞胚胎学研究表明,ＰＤＥＲ是二倍体植物２ｎ＝２４,约有５０％胚囊的卵细胞未经受精能自行发育形成胚,成熟种子的萌发和生长速度较常规正常水稻快。ＰＤＥＲ的大孢子母细胞经有丝分裂产生未减数的胚囊,即无融合生殖中的二倍体孢子生殖类型。在胚囊形成和发育过程中有如下几个特点：（１）孢原细胞至大孢子母细胞分裂前的过渡期持续时间较长,孢原细胞和大孢子母细胞的细胞质比周围的珠心细胞质稀淡。（２）大孢子母细胞经二次有丝分裂后形成直线排列的三个细胞（三分体）,珠孔端的两个解体,合点端的一个发育为功能细胞,有少数胚囊的三个细胞全部解体形成败育胚囊。（３）功能细胞经三次连续核分裂形成具八核七个细胞的成熟胚囊,它的结构与常规正常水稻基本相同,但助细胞呈长形而没有回抱着卵细胞。     

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.     

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.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

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).     

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.