新疆雪莲植株再生体系研究初探

以新疆雪莲叶片、叶柄和根为外植体,诱导新疆雪莲植株再生,获得愈伤组织诱导、分化和生根最佳培养基,并初步建立其再生体系.研究结果表明:所用培养基均能诱导出愈伤组织且诱导率最高可达100%,分化率最高可达78%.对不同外植体的愈伤组织诱导结果表明:叶片和叶柄的诱导效果最好,根的诱导效果较差.其中对叶片愈伤组织诱导效果最好的培养基是MS+NAA0.50 mg/L+2,4-D0.10 mg/L+6-BA1.00mg/L,对叶柄的诱导效果最好的培养基是MS+NAA1.00mg/L+2,4-D0.10mg/L+6-BA0.10mg/L;分化培养基以MS+NAA0.20 mg/L+6-BA1.00mg/L较适宜,生根培养基以1/2MS0+NAA1.00mg/L较适宜.     

小桐子愈伤组织的诱导

本文以小桐子的叶片、叶柄、茎段及下胚轴和子叶作为外植体,研究不同外植体类型对愈伤组织诱导的影响,结果表明叶柄的诱导率最高,其次为茎段的诱导率。同时以小桐子的下胚轴作为外植体,研究植物生长调节剂种类及浓度配比对愈伤组织诱导的影响,结果显示6-BA与2,4-D的组合更适宜小桐子愈伤组织的诱导,MS+6-BA0.5mg/L+2,4-D0.1mg/L为小桐子愈伤组织诱导的最佳培养基,其愈伤组织诱导率高达96.7%。本研究为小桐子愈伤组织的分化、植株再生及相关的遗传转化研究提供了参考。     

长柄双花木愈伤组织诱导及植株再生

以长柄双花木当年生嫩梢上的叶柄、嫩茎、嫩叶为外植体,对影响长柄双花木愈伤组织诱导和继代、分化主要因素进行研究。结果表明:在培养基MS+NAA0.5mg/L+2,4-D2.0mg/L上,三种外植体均可诱导出愈伤组织,其中叶片愈伤组织诱导率最高。该培养基还可作为愈伤组织继代培养基,但继代培养周期不超过2周。愈伤组织接种在MS+BA2mg/L上分化不定芽,根的诱导在1/2MS+IBA0.5mg/L培养基上进行。     

黄花补血草愈伤组织的诱导和植株再生

以黄花补血草(Limonium aureum(L.)Hill.)无菌苗为材料,研究了不同激素配比条件下不同外植体愈伤组织的诱导及植株再生.结果表明,黄花补血草无菌苗叶片、叶柄和幼根均可作为离体培养的外植体,但叶片和叶柄的诱导率明显高于幼根.将外植体接种于分别添加0.5 mg/L NAA或1.0 mg/L 2,4-D或0.3-0.5 mg/L 6-BA 0.5-2.0 mg/L NAA的MS培养基上,经过14-28 d培养后,可脱分化产生乳白色、红色或浅绿色颗粒状或致密愈伤组织,频率达到70%以上.在MS 0.3 mg/L 6-BA 1.0 mg/L NAA培养基上,红色和绿色颗粒状愈伤组织经过1-2次继代后,均可分化产生不定芽,进而形成丛生芽,分化率达到100%.将高约3 cm的丛生芽切下,接种于分别添加0.5 mg/L IAA或0.5 mg/L IBA的1/2 MS培养基上可产生不定根,获得完整的再生植株.     

新疆天山雪莲体胚诱导与分化研究

以新疆天山雪莲的叶片为外植体,分别用不同配方培养基诱导愈伤组织,后进行体胚诱导和分化培养形成再生雪莲植株.结果表明,诱导愈伤组织的最适培养基为MS 2,4-D 0.5 mg/L BA 1.5 mg/L,诱导率可达到100%;愈伤组织转移至MS 2,4-D 0.5 mg/L BA 1.5 mg/L培养基进行继代培养,增殖后的愈伤组织转移到MS 2,4-D 0.2 mg/L的液体培养基后成功诱导出雪莲体胚,出胚率达40%;将体胚接至MS ABA 0.5 mg/L培养基后,结果分化生长出大量的再生雪莲幼苗.     

药用植物金荞麦愈伤组织诱导与植株再生

目前转基因技术已成为植物定向遗传改良的重要手段,而建立稳定高频的离体再生系统是实现遗传转化的基础和前提.本试验以25 ～30 d苗龄的金养麦(Fagopyrum dibotrys)无菌苗叶片、茎节间、叶柄为外植体进行愈伤组织诱导与植株再生研究.结果表明:叶片在MS +2,4-D 4.0 mg/L +6-BA 1.0 mg/L培养基上愈伤组织诱导率达到89％.茎节间在MS +2,4-D 2.0 mg/L +6-BA 2.0 mg/L培养基上愈伤组织诱导率为87％.叶柄在MS +2,4-D 4.0 mg/L +6-BA 2.0 mg/L+ IBA 0.2 mg/L培养基上的最高诱导率仅为54％.愈伤组织分化不定芽的适宜培养基为MS +6- BA2.0 mg/L +TDZ0.2 mg/L +NAA0.2 mg/L;金荞麦不定芽在1/2 MS +NAA 0.5 mg/L的培养基上生根效果最好.组培再生植株经炼苗后移栽到田间成活率达80％以上,且生长表现正常.高频完整再生体系的建立,为金荞麦进一步遗传操作和扩大药材资源奠定了基础.     

扁桃愈伤组织诱导及分化的研究

以扁桃优良品种'Naporeil'的茎段、叶片和花药作为外殖体,分别对其进行愈伤组织诱导和分化研究,以筛选愈伤组织的最佳诱导增殖培养基、分化培养基和生根培养基.结果表明,该品种以茎段、花药作为外殖体最易诱导获得愈伤组织,叶片不适宜作为外殖体诱导愈伤组织;愈伤组织的最佳诱导增殖培养基均为B5+0.5 mg/L 2,4-D+0.2 mg/L 6-BA+1.0 mg/L NAA,愈伤组织诱导率为100%,增殖倍数最高可达7倍;茎段愈伤组织的分化培养基为MS+0.2 mg/L NAA+0.8 mg/L 6-BA+0.5 mg/L ZT,分化率为71%;花药愈伤组织未见分化.由茎段愈伤组织再分化获得的不定芽在1/2MS+0.5 mg/L IBA培养基上诱导生根,并给以黑暗预处理可使生根率达80%以上.     

何首乌愈伤组织的诱导

研究了外植体、光暗条件、植物激素等因子对何首乌愈伤组织诱导的影响 ,以及 6 -BA和何首乌组织提取液对愈伤组织增殖的影响。结果表明 :茎段的愈伤组织诱导优于带侧芽茎段和叶片 ;光照有利于愈伤组织的诱导 ;4因子 4水平的正交实验表明 ,对何首乌茎段愈伤组织诱导的影响 2 ,4 -D >6 -BA >IBA >IAA ,最佳激素搭配是 :MS +2 ,4 -D 2mg L +6 -BA 1mg L +IBA1mg L或MS +2 ,4 -D 2mg L +6 -BA 2mg L +IAA 1mg L ;MS培养基中附加 6 -BA或组织提取液均促进愈伤组织的增殖。     

商陆离体再生体系的构建

目的:建立商陆离体再生体系。方法:选取商陆的幼茎、茎节、叶片、叶柄和顶芽为外植体,以MS作为基本培养基,通过添加不同浓度配比的植物生长调节剂分别进行愈伤组织、丛生芽和生根诱导,筛选商陆离体再生体系方案。结果:顶芽和幼茎为外植体诱导的愈伤组织出愈时间早,愈伤组织质量高,以培养基MS+6-BA0.5 mg/L+2.4-D 0.5 mg/L的诱导率最高,达到100%;其中,只有以顶芽产生的愈伤组织才能分化出丛生芽,芽分化培养基为MS+6-BA 2.0 mg/L+NAA 0.25 mg/L,诱导率为98%;诱导生根的适宜培养基为1/2 MS+NAA 0.3 mg/L,诱导率达100%。结论:建立和完善了商陆离体再生体系方案,为商陆遗传转化体系的构建奠定了基础。     

曼陀罗茎段愈伤组织诱导和再生植株的研究

本试验以曼陀罗茎段为外植体,在附加不同植物激素组合的培养基中对愈伤组织的诱导和植株再生进行研究。结果表明:采用修改的MS培养基(除去甘氨酸,维生素B1含量增加至0.5mg/L,pH5.5)附加2mg/L2,4-D可由曼陀罗茎段诱导大量胚性愈伤组织;愈伤组织继代选用0.5mg/L2,4-D为宜;不定芽的诱导采用MS培养基(20g蔗糖,8g琼脂,0.1g水解干酪素) 6-BA(0.5mg/L);幼苗进一步转接至1/2MS IBA(0.2mg/L)生根培养基中,可完成曼陀罗茎段愈伤组织诱导和再生植株的组织培养过程。     

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.