长效油菜素内酯TS303和二氢茉莉酸丙酯协同提高大豆光合能力

研究了长效油菜素内酯TS303、二氢茉莉酸丙酯(PDJ)及二者复配对大豆光合作用的影响及作用机理。试验结果表明：(1)0.01~1 mg·L^-1 TS303浸种促进大豆干物质积累, 以0.1 mg·L^-1的浓度效果最好, TS303对干物质在地上部和根之间的分配没有明显的影响, 1～10 mg·L^-1 PDJ浸种促进干物质积累, 以5 mg·L^-1增幅最大,50和100 mg·L^-1则抑制干物质积累,1～100 mg·L^-1 PDJ均促进同化物质向根系分配;(2)0.1 mg·L^-1 TS303和5 mg·L^-1 PDJ能增加大豆光合叶面积及净光合速率, 增强光合能力, 二者混合使用表现出协同效应;(3)0.1 mg·L^-1 TS303和5 mg·L^-1 PDJ及二者复配增加叶绿素含量和提高PSⅡ的实际光转化效率 (ФPSⅡ), 二者对ФPSⅡ的提高途径不同, TS303增加光合淬灭(qP)而对有效光转化效率(Fv′/Fm′)影响不大, PDJ增加Fv′/Fm而对qP影响不大;(4)0.1 mg·L^-1 TS303和5 mg·L^-1 PDJ及二者复配增加大豆气孔导度、碳酸酐酶活性、RuBPCase含量和活性, 增强CO₂转运和固定能力;(5)0.1 mg·L^-1 TS303和5 mg·L^-1 PDJ及二者复配增加叶片中蔗糖的含量, 提高蔗糖/淀粉比率, 加快同化物质的转运, 增加根中淀粉含量。总体上, TS303在光能转化和CO₂固定方面效果好于PDJ, 而PDJ促进同化物质运出效果好于TS303, 这可能是二者协同提高大豆光合能力的原因。     

廊坊杨3号快繁和转基因的再生系统

对杂交杨树新品种廊坊杨3号（Populus langfangensis 3,(P. deltoides (“Shan Hai Guan”)×((P. simonii × pyramidalys)₁₂×Ulmus pumila) 的离体叶片和茎段在附加BA、NAA、IBA和2,4-D的MS培养基上的直接和间接的器官分化、愈伤组织形成和植株再生进行了研究。叶柄和叶片最容易在叶脉处直接诱导生芽。从叶片直接诱导生芽的激素条件为1～2 mg·L^-1 BA和0.5 mg·L^-1 IBA,最高生芽率可达90%。2,4-D促进愈伤组织的形成。由愈伤组织诱导生芽的激素条件为0.3～0.5 mg·L^-1 BA 和 0.02 mg·L^-1 IBA或NAA,生芽率达76%。较好的生根条件为0.1 mg·L^-1 BA和0.2～0.5 mg·L^-1 IBA,生根率可达67％。以上再生条件为廊坊杨3号的转基因育种和无性快繁技术提供了可能。     

铝胁迫下北美车前和车前生长及叶绿素荧光特性的比较研究

采用系列浓度AlCl₃溶液（100、500、800、2 000 mg·L^-1）进行处理,在处理后不同时间（0,10、20、30 d）,测定北美车前（Plantago viriginica）和车前(P.asiatica)的生长及叶绿素荧光特征指数,旨在比较外来入侵种北美车前和同属本地种车前的生长及叶绿素荧光对铝胁迫响应的差异。结果表明,车前和北美车前的根冠比在轻度铝（Al³⁺=100 mg·L^-1）处理下略有上升,在中度（Al³⁺=500 mg·L^-1）以上铝浓度处理下开始显著下降;叶绿素a、b含量在轻度铝处理下变化不明显,随着铝浓度的增加和处理时间的延长呈现明显下降趋势;叶绿素荧光参数F_v/F_m、Φ_PSⅡ及F_v/F_o值在低浓度铝的短时间处理下略有上升,随着铝浓度的升高和处理时间的延长则明显下降。结果表明铝胁迫对上述两种植物的生长和叶绿素荧光参数均有一定影响,但北美车前各参数的下降幅度小于车前,表现出比车前更为耐铝的生理特性。     

加拿大金露梅离体培养与快繁体系的建立

以加拿大金露梅嫩芽、叶片为外植体进行试验,通过观察确定嫩芽为初代培养的外植体。运用L₉(3⁴)正交试验筛选出最适合的腋芽初代培养、芽苗继代增殖及组培苗生根的最佳培养基,从而为金雨点建立了一套“腋芽诱导—继代增殖—生根培养”的快速繁殖体系。结果表明,诱导腋芽的分化培养基为MS+6-BA 2 mg·L^-1+NAA 0.1 mg·L^-1,其中MS、6-BA和NAA均为诱导的主要因子,影响顺序为MS＞6-BA＞NAA,诱导率达96.33%;继代增殖培养中激素6-BA是影响加拿大金露梅芽增殖生长的主要激素,差异极显著（p=0.000 1）,并且以浓度为2.0 mg·L^-1的增殖效果最好,确定最佳培养基为MS+6-BA 2.0 mg·L^-1+NAA 0.6 mg·L^-1+KT 0.2 mg·L^-1,半月增殖倍数达6.12;对生根培养3种激素（KT、NAA、IBA）进行方差分析, KT和NAA的影响均达到了显著水平(p=0.000 1; 0.001 0),是影响生根的主导因子,而IBA的p值为0.424 5,因此可以忽略其影响,在诱导时确定用NAA和KT两种激素。之后对生根数量、生根率进行多重比较表明最终确定生根培养基为MS+NAA 0.1 mg·L^-1+KT 1.0 mg·L^-1,生根数为8.63条,生根率为95.33%。     

马蔺组织培养快繁技术体系研究

以成熟且具活力的马蔺种子为外植体,以MS为基本培养基,与不同浓度比例的2,4-D、BA、NAA、KT等植物生长调节剂构成愈伤组织诱导、分化、生根等培养基的组合方案,对马蔺组织培养快繁技术开展系统研究。结果表明,不同植物生长调节剂组合的培养基对愈伤组织的诱导率有显著影响,MS+2,4-D 4 mg·L^-1+BA2 mg·L^-1、MS+2,4-D 4 mg·L^-1+BA5 mg·L^-1和MS+2,4-D 2 mg·L^-1+KT1.5 mg·L^-1为最佳诱导培养基,诱导出愈率均在58%以上,显著高于其它培养基组合方案（p<0.05）;最佳分化培养基为MS+BA4 mg·L^-1和MS+BA1 mg·L^-1+NAA0.15 mg·L^-1,绿苗分化率高达100%,生长势好,状态叶和分化芽丛质量好;适宜继代增殖培养基为MS+BA2 mg·L^-1+NAA0.1 mg·L^-1、MS+BA1 mg·L^-1+NAA0.2 mg·L^-1;1/2MS为最适宜的生根培养基,1/2MS+IBA0.5 mg·L^-1、1/2MS+IBA0.5 mg·L^-1+NAA0.5 mg·L^-1两种组合也相对较好;试管苗不需炼苗可直接出瓶移栽于V_田土∶V_河沙=2∶1的土壤基质,成活率在95%以上。从而为马蔺提供了一套从“成熟种胚—诱导愈伤组织—绿苗分化—继代增殖—生根—试管苗移栽”等整个过程中各环节的最佳培养基和操作规程的组培快繁体系。     

利用正交设计优化小苍兰ISSR-PCR反应体系

通过L₁₆(4⁵)正交试验,研究了镁离子浓度、dNTP浓度、模板DNA浓度、Taq DNA聚合酶浓度、引物浓度这5个因素在4个水平上对ISSR-PCR的影响,建立了适合于小苍兰ISSR-PCR的反应体系。优化体系为：25 μL PCR反应体系中含有1×Taq酶缓冲液(10 mmol·L^-1 KCl,8 mmol·L^-1(NH₄)₂SO₄,10 mmol·L^-1 Tris·HCl,pH 9.0,0.05% NP-40),2 mmol·L^-1 MgCl₂,0.06 U·μL^-1 Taq酶,0.4 μmol·L^-1引物,4.0 ng·μL^-1模板DNA,dATP、dCTP、dGTP、dTTP各0.6 mmol·L^-1。利用温度梯度PCR,确定了最适宜的退火温度为51.5℃。该优化体系的建立为下一步对小苍兰进行ISSR分子标记奠定了基础。     

浸种对镉胁迫下油菜种子萌发及幼苗生长的影响

通过水培实验研究了La(NO₃)₃浸种对镉胁迫下油菜（Brassica napus）种子萌发及幼苗生长的影响。结果表明,当镉浓度≤10 mg·L^-1时,La(NO₃)₃浸种（0～50 mg·L^-1）能提高油菜种子的活力,促进油菜幼苗的生长,并提高脂肪酶的活性和幼苗根细胞有丝分裂指数。其中以10 mg·L^-1 La(NO₃)₃浸种处理效果最佳,与对照相比,种子活力指数及油菜幼苗各生长指标显著提高,脂肪酶活性增加40.41%～65.09%,幼苗根细胞有丝分裂指数增加62.76%～77.02%。当镉浓度>10 mg·L^-1时,La(NO₃)₃浸种对镉胁迫的缓解效用明显减 弱,与对照相比,仅脂肪酶活性显著提高,其它指标无明显变化。     

野葛叶片和茎段高频再生体系的建立

探讨几种因子对野葛叶片和茎段高频再生体系建立的影响。采用植物组织培养、正交实验和单因子实验的方法。野葛叶片和茎段的最佳消毒方式为70%酒精处理30 s后再用0.1%HgCl₂处理15 min;野葛叶片愈伤组织诱导的最佳培养基为MS+NAA 1.0 mg·L^-1+2,4-D 2 mg·L^-1,野葛茎段愈伤组织诱导的最佳培养基为MS+NAA 0.5 mg·L^-1+6-BA 1.0 mg·L^-1+2,4-D 2 mg·L^-1;暗培养更有利于野葛愈伤组织的诱导;野葛叶片和茎段愈伤组织诱导的最佳蔗糖浓度均为30 g·L^-1;野葛叶片愈伤组织的最佳出芽培养基为MS+NAA 1.0 mg·L^-1+6-BA 3.0 mg·L^-1,而野葛茎段愈伤组织的最佳出芽培养基为MS+ NAA 0.5 mg·L^-1+KT 2 mg·L^-1;光照培养更有利于野葛叶片和茎段愈伤组织芽的再分化;野葛叶片愈伤组织再生芽生根的最佳培养基为MS+NAA 0.5 mg·L^-1+PP₃₃₃ 0.5 mg·L^-1,而野葛茎段愈伤组织再生芽生根的最佳培养基为MS+NAA 0.5 mg·L^-1+PP₃₃₃ 3.0 mg·L^-1;野葛叶片和茎段愈伤组织再生芽生根的最佳蔗糖浓度均为30 g·L^-1;叶片再生苗移栽的最佳PP₃₃₃浓度为1.0 mg·L^-1,茎段再生苗移栽的最佳PP₃₃₃浓度为3.0 mg·L^-1;叶片和茎段再生苗的最佳移栽基质均为蛭石:珍珠岩（2:1）。     

一氧化氮(NO)熏蒸蒜瓣对蒜苗叶片光合作用的影响

以白皮改良蒜为试验材料,用不同浓度的一氧化氮气体（0.1、0.5、1.0 μmol·L^-1）在无氧环境中对大蒜进行熏蒸。并使用TPS 1便携式光合仪结合Farquhar和Sharkey的理论测定或计算NO处理蒜苗的相关光合指标,同时测定核酮糖-1,5-二磷酸羧化/加氧酶(Rubisco)含量。发现与1.0 μmol·L^-1 NO气体处理相比,0.5 μmol·L^-1 NO处理的蒜苗叶片净光合速率（P_n）、气孔导度(G_s)提高、而胞间隙CO₂浓度（C_i）、气孔限制值(L_s)降低,说明0.5 μmol·L^-1 NO处理下蒜苗光合速率高于1.0 μmol·L^-1 NO的处理的主要是非气孔因素。而且0.5 μmol·L^-1 NO处理提高了蒜苗叶片表观量子效率(AQY)、表观羧化效率(CE)和光合能力(A_o)及Rubisco含量,说明外源NO处理提高了蒜苗叶片光合作用过程中光反应能力和碳同化过程中羧化酶羧化效率。与对照相比,1.0 μmol·L^-1 NO处理降低了蒜苗叶片净光合速率,同时气孔导度、胞间隙CO₂浓度、表观量子效率、Rubisco含量、羧化效率和光合能力均降低,而气孔限制值升高,说明1.0 μmol·L^-1 NO对蒜苗光合作用的抑制既有气孔因素,也有非气孔因素。而0.1 μmol·L^-1 NO处理各项指标与对照无显著性的差异。     

濒危植物珙桐的组织培养与植株再生

以珙桐冬芽为材料进行组织培养和植株再生研究,结果表明：珙桐冬芽直接诱导丛生芽的最适培养基为WPM+NAA 0.2 mg·L^-1+6-BA 3.0 mg·L^-1+AC 2.0 g·L^-1;珙桐带芽茎段增殖的适宜培养基为WPM+NAA 0.05 mg·L^-1+6-BA 1.0 mg·L^-1+GA₃ 2.0 mg·L^-1+AC 2.0 g·L^-1;生根最佳培养基为White+IBA3.0 mg·L^-1+6-BA 1.0 mg·L^-1+AC 2.0 g·L^-1,在此条件下,根发育良好,植株健壮;组培苗炼苗后移栽,成活率可达80%。     

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.     

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.