辣椒再生体系不定芽发生因素的优化研究

以辣椒(Capsicum annuum L)品种"哈椒一号"为试材,选用无菌苗子叶、下胚轴和带柄子叶为外植体,采用正交设计探讨不同外植体、激素组合和AgNO_2浓度等因素对不定芽分化的影响,筛选出了三种外植体不定芽诱导的最适培养基。试验结果表明:在不定芽的分化中,6-BA与IAA相配合使叶片不定芽分化频率明显提高,BA/IAA的比例对不定芽分化有明显影响。并且6-BA 6 mg/L+IAA 2 mg/L的组合能够达到最高的诱导率。AgNO_3不但显著提高了不定芽诱导的频率,并且还缩短了不定芽的发生时间。另外,三种外植体的不定芽诱导率,带柄子叶最高,其次是子叶,下胚轴最差。最适不定芽培养基:MS+6-BA 6 mg/L+IAA 2 mg/L+AgNO_2 4 mg/L,pH 5.8,最高不定芽分化率达88.2%。     

香石竹叶片离体再生体系的建立

以香石竹(Dianthus caryophyllus Linn.)无菌苗叶片为外植体,从不同细胞分裂素及其他激素配合使用等方面进行筛选,建立香石竹叶片离体再生体系.结果表明,不同的细胞分裂素影响叶片不定芽分化频率,其中较低浓度的6-BA(0.5 mg·L-1)和TDZ(0.001 mg·L-1)配合使用能有效诱导香石竹叶片不定芽分化;添加一定浓度的PP333(4 mg·L-1)可提高叶片不定芽分化频率和平均芽数.香石竹叶片不定芽分化的适宜培养基为:MS 0.002mg·L-1TDZ 0.5 mg·L-16-BA 0.2 mg·L-1IAA 4 mg·L-1PP333;壮苗培养基为:MS 0.2 mg·L-1 6-BA 0.2 mg·L-1IAA;生根培养基为:1/2 MS.不定芽诱导频率达到42.61%,平均芽数为4.53个.     

万寿菊杂交亲本的离体培养

以万寿菊‘钻石’雄性不育株的幼嫩叶片和子房为外植体进行离体快繁,结果表明:培养基MS+0.8 mg·L-1 IAA+0.6 mg·L-1 6-BA+30 g·L-1蔗糖既有利于叶片愈伤组织的诱导也有利于不定芽的分化,愈伤组织诱导率达97.9％,不定芽诱导率达45.8％;培养基MS+0.5 mg·L12,4-D+0.5 mg·L-16-BA+ 30 g·L-1蔗糖为诱导子房愈伤组织的最佳培养基,出愈率为77.8％;培养基MS+0.05 mg·L -1 NAA+0.5 mg·L-1 6-BA+ 30g·L-1蔗糖为诱导子房愈伤组织不定芽分化的最佳培养基;将不定芽接至MS培养基上,7d后即可生出不定根,生根率可达98％,移栽成活率达90％以上.     

黑莓品种‘Arapaho’离体叶片不定芽诱导影响因素分析及再生体系建立

以黑莓(Rubus spp.)品种‘Arapaho’无菌苗叶片为外植体,通过正交和单因素实验分别研究了基本培养基类型、6-BA和1BA质量浓度以及暗培养时间、外植体的叶位和接种方式对不定芽诱导的影响,并研究了IBA质量浓度对不定芽生根的影响;在此基础上,初步建立了黑莓品种‘Arapaho’离体叶片的再生体系.正交实验结果表明:基本培养基类型对叶片不定芽诱导率及平均不定芽数的影响最大,而IBA质量浓度对叶片不定芽诱导率及6-BA质量浓度对平均不定芽数的影响较小;适宜‘Arapaho’叶片不定芽诱导的最佳培养基为含有2.0mg·L-16-BA和1.0 mg·L-1IBA的MS培养基.单因素实验结果表明:暗培养时间、外植体的叶位及接种方式对不定芽诱导率有显著影响;最适宜的暗培养时间为21 d;植株中、上部叶片的再生能力较强,其中第3和第4位叶的不定芽诱导效果最佳;叶面朝上接种更有利于不定芽的诱导.在含0.2 mg·L-1 IBA的MS培养基中,不定芽生根率达100.0％,且根数多、长势良好.黑莓品种‘Arapaho’离体叶片的再生体系为:以无菌苗的第3和第4位叶为外植体,经过适当修剪后叶面朝上接种于含有2.0 mg·L-16-BA和1.0 mg·L-1IBA的MS培养基上,暗培养21 d后置于光照条件下培养30 d;将不定芽转接到含有0.5 mg·L-16-BA和0.3mg·L-1 NAA的MS培养基上进行继代培养;当不定芽高约2 cm时转接到含有0.2 mg·L-1IBA的MS培养基上进行生根培养,最终获得完整植株.     

乌桕不同外植体高效再生探索

以乌桕的成熟胚、胚乳、叶片和茎段为外植体,建立高效、稳定的组培快繁再生体系,并成功获得其再生苗.结果表明:(1)全胚乳带胚的愈伤组织诱导率达90%,其愈伤组织继续在MS+1.0 mg·L-1 NAA+1.0 mg·L-1 6-BA培养基上培养,不定芽最多达15个/外植体.(2)去胚乳的胚不加调节剂则胚直接萌动成苗,萌动率和成苗率可达100%;去胚乳的胚在MS+0.05 mg·L-1 NAA+0.3 mg·L-1 6-BA最佳培养基中培养,其胚轴处可直接诱导不定芽,最多达6个/外植体.(3)无菌苗叶片在MS+0.5 mg·L-1 NAA+0.5 mg·L-1 6-BA培养基中诱导的有效不定芽数最高达18个/外植体,诱导率达90%.(4)茎段在MS+0.05 mg·L-1 NAA+0.1~0.3 mg·L-1 6-BA培养基上不定芽的诱导率较高(100%),直接诱导的不定芽数最多达17个/外植体.(5)芽苗在1/2MS+0.5 mg·L-1 IBA上生根率达到100%,但根系较细弱,而在MS+1.0 mg·L-1镧稀土中的生根率达100%,且根系粗壮;生根的小苗练苗移栽后温室内成活率为89.2%,移栽到室外沙质土壤中的成活率为68.9%.     

崖白菜的愈伤组织诱导及植株再生

通过愈伤组织诱导不定芽发生途径,建立了崖白菜的组培再生体系,研究了崖白菜幼嫩子房和不同植物生长调节剂对其愈伤组织诱导和不定芽发生的影响。结果表明,以崖白菜的幼嫩子房作为外植体,诱导子房分化形成愈伤组织的最适培养基为MS＋6．BA1．0mg·L-1＋2,4-D0．2mg·L-1,诱导率可达82．83％;最适的不定芽分化培养基为Ms＋6-BA0．5mg·L-1＋NAA0．1mg·L-1;诱导不定芽生根的最适培养基为1／2MS＋NAA0．1mg·L-1。     

LA系列百合‘Eyeliner’花器官组培快繁技术研究

该试验以LA系列百合‘Eyeliner’花器官为外植体,通过不定芽直接诱导和愈伤组织再分化2种途径,建立了花器官组培快繁技术体系。结果表明:以花器官为外植体污染率接近于0;4种百合花器官诱导从易到难的顺序为花梗、花丝、子房和花柱;花丝易诱导愈伤组织,花梗易诱导不定芽,最适诱导培养基均为MS+1.0mg·L-1 6-BA+0.5mg·L-1 NAA;不定芽增殖最佳培养基为MS+2.0mg·L-1 6-BA+0.2mg·L-1 NAA,愈伤组织分化最佳培养基为MS+1.5mg·L-1 6-BA+0.2mg·L-1 NAA;诱导生根最佳培养基为MS+45g·L-1蔗糖;最佳炼苗方式为将组培苗封口放置在自然环境中3d,然后开口放置在自然环境条件下2d;当试管苗鳞茎大小为3.15cm时,移栽成活率最高;移栽最佳基质为草炭∶蛭石∶珍珠岩=2∶1∶1。     

耐冬山茶子叶再生体系的研究

青岛市市花——耐冬山茶为北方珍贵的冬季观赏物种,目前其栽培数量不能满足园林应用,亟需通过组培扩繁。以耐冬山茶的子叶为外植体,探讨不同因素对子叶愈伤组织诱导及植株再生的影响。结果表明,使用2%的NaClo对耐冬山茶果实灭菌的较佳时间是8 min,子叶愈伤组织的诱导率为100%。耐冬山茶子叶愈伤组织增殖的较优激素配比为0.5 mg·L^-1NAA+1.5 mg·L^-16-BA,其最大增殖量为4.06。将经过2次转接继代培养后的愈伤组织转入不定芽分化培养基MS+1.0mg/LNAA+10.0 mg·L^-16-BA进行不定芽的分化诱导,不定芽的分化率为10.7%。将耐冬山茶的不定芽芽条基部浸没在500 mg·L^-1的IBA溶液中70 min,再转接到1/2MS固体培养基,生根率达40%,成功建立了耐冬山茶子叶的植株再生体系。     

橡胶树未成苗体细胞胚的茎芽分化及利用

以橡胶树未成苗体细胞胚为试材,选取未成苗双子叶胚、连体胚、多子叶胚、单子叶胚和子叶愈伤化胚作为外植体,研究不同体细胞胚类型的外植体分化茎芽的情况,并利用其进行幼态微型芽条的培育研究。结果表明:在植株诱导培养基中培养80d后,未成苗双子叶胚、连体胚、多子叶胚、单子叶胚、子叶愈伤化胚均能分化出芽,双子叶胚分化率最高(达90%),单子叶胚最低(20%),多子叶胚和连体胚最多可分化出芽3个,双子叶胚2个。幼态微型芽条增殖的最优培养基为MS+6-BA2mg·L-1或MS+6-BA2mg·L-1+KT1mg·L-1,而添加NAA对芽的伸长有抑制作用;适宜幼态微型芽条伸长培养的基本培养基为MS。     

影响大白菜高效离体培养再生的因素

大白菜的4日龄子叶和6日龄下胚轴外植体在MS 4～6 mg*L-1 6-BA 0.5 mg*L-1 NAA 5～10 mg*L-1 AgNO3培养基上3～4周后分化出不定芽,带柄子叶和子叶圆片最高再生频率均可达到80%～90%,下胚轴再生频率为40%～55%,在1/2MS 0.2 mg*L-1 IBA培养基上100%生根,据此建立了大白菜离体培养再生系统.     

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.