几种同工酶与猕猴桃品种对溃疡病抗性关系的研究

应用聚丙烯酰胺凝胶电泳、同工酶分析技术分别研究了猕猴桃植株体内过氧化物酶(POD)、多酚氧化酶(PPO)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、酯酶(EST)同工酶谱带的变化,结果表明:自然感染溃疡病前后,此6种同工酶谱带特征在不同抗感品种中表现出一定的差异.未感染溃疡病菌前,抗(感)品系枝条、叶片POD同工酶均有2条酶带,PPO同工酶有3条酶带,但感病品种酶带颜色深且粗,而抗病品种酶带颜色浅且细,叶片酶带颜色深于枝条;SOD、CAT同工酶谱带均为1条,Rf值分别为0.38、0.28,感性品种较抗耐品种谱带亮度高活性强;自然发病后,抗(感)品系POD、PPO同工酶谱带数都增加,分别为4、3条和5、4条,且抗病品种新酶带出现较感病品种早且酶带粗颜色深活性强,感病品系虽也有新酶带出现,但酶带少活性弱,抗病品系枝条、叶片POD、PPO同工酶新谱带的Rf值分别为0.63、0.67和0.85、0.87;抗感病品种SOD、CAT同工酶都被诱导产生了1条新的同工酶谱带,Rf分别为0.32和0.27,新酶带现色时间迟,且酶带颜色浅活性弱,但抗耐品种较感性品种谱带亮且活性强;EST同工酶于自然发病前后变化不大,与抗病性关系不很明显.     

芦苇耐脱水能力的生理生态学分析

甘肃省河西走廊分布有不同生态环境的芦苇,包括沼泽芦苇、盐化草甸芦苇和沙丘芦苇。盐化草甸芦苇和沙丘芦苇表观出很强的耐脱水能力。 测定与植物耐脱水能力相关的SOD、CAT和POD活力,表现为SOD活力以沙丘芦苇最高,盐化草甸芦苇次之,沼泽芦苇最低,但CAT和POD则以沼泽芦苇高于其它生境芦苇。用聚丙烯酰胺垂直板电泳方法分析这3种酶同工酶谱,结果表明,3种不同生境芦苇的SOD同工酶谱基本相同,均有9条酶带,但沙丘芦苇和盐化草甸芦苇的CAT和POD同工酶带数比沼泽芦苇分别增多3条和2条。这些结果证明,芦苇在自然选择压力下形成的耐脱水能力与基因调控的酶多型性相关。     

He-Ne激光处理不同时期蚕豆幼苗对抗氧化系统的影响

采用功率为3.50 mW/mm2的He-Ne激光处理不同时期蚕豆,研究其四叶期叶片中丙二醛(MDA)含量,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性及同工酶谱的变化。结果表明,与对照相比,He-Ne激光处理不同时期蚕豆,MDA含量均显著降低,且各处理间没有显著差异;SOD、POD、CAT酶活性有不同程度提高。SOD、POD同工酶的酶谱在浸种24小时和胚芽露头期经激光处理后改变,在一叶期处理后没有改变;CAT同工酶谱没有变化;在一叶期处理的三种同工酶谱都没有改变。     

硝酸银和乙烯利对黄瓜叶片中3种氧化还原酶同工酶和酶活性影响的比较

黄瓜经300 mg*L-1硝酸银和200 mg*L-1乙烯利处理后,叶片中过氧化物酶(POD)和超氧化物歧化酶(SOD)两种同工酶的酶谱带数和酶活性均明显受到诱导,而过氧化氢酶(CAT)几乎不受影响.两种药剂处理的POD和SOD酶谱和活性变化有明显差异,硝酸银诱导两种酶带和活性高峰出现早,而乙烯利则能诱导更多的酶带数.两种药剂诱导POD和SOD有同时增强表达的效果.     

铅胁迫对黄瓜幼苗抗氧化酶活性及同工酶的影响

采用水培法和聚丙烯酰胺凝胶电泳法,研究铅胁迫对黄瓜幼苗过氧化物酶(POD)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性及同工酶的影响.结果表明,铅胁迫下黄瓜幼苗地上部POD活性除第5天外均随铅浓度的增加而逐渐降低,POD同工酶谱带和表达量减少.在0～500 mg·L^-1铅浓度范围内,SOD活性随铅浓度的增加而增加,第7天达到最大值后急剧下降,低于同期对照值,900 mg·L^-1铅处理SOD活性随时间的延长逐步降低,SOD酶谱带和表达量与铅浓度呈负相关.CAT酶谱带无明显变化,而表达量存在差异.     

甜椒雄性不育两用系AB91不育株与可育株花药同工酶分析

通过聚丙烯酰胺凝胶电泳法（PAGE）对甜椒核雄性不育两用系AB91不育株与可育株的花药过氧化物酶（POD）、过氧化氢酶（CAT）和酯酶（EST）同工酶谱带的分析,以及对其超氧化物歧化酶（SOD）同工酶活性的分析结果表明,这几种同工酶的活性和谱带均与不育性有一定的关系,具体表现为POD、CAT、EST在不育株谱带数少,而可育株谱带数多;POD、SOD的活性不育株高于可育株,而CAT、EST的活性则是可育株高于不育株。     

大别山区六种黄精属植物的五种同工酶分析

采用聚丙烯酰胺凝胶电泳法对皖西大别山区六种黄精属植物的抗坏血酸氧化酶(AOD)、多酚氧化酶(PPO)、超氧化物歧化酶(SOD)、酯酶(EST)和过氧化物酶(POD)五种同工酶进行了比较分析。结果表明:(1)五种同工酶共显示出66条酶带,其中有3条是黄精属的特征酶带;并且来源于不同种的同一种酶的谱带数、相对迁移率、酶活性均不相同,呈现多样性;(2)五种同工酶谱的模糊聚类分析结果与形态学分类的结果一致,利用酶谱差异可以将六种黄精初步区分;(3)在六种黄精属植物中,湖北黄精、轮叶黄精、多花黄精和金寨黄精是较进化类型,玉竹和长梗黄精是较原始类型。     

干旱胁迫下内生真菌感染对黑麦草叶内几种同工酶的影响

以内生真菌感染(endophyte-infected,EI)与不感染(endophyte-free,EF)的黑麦草(Lolium perenne L．)种子建立实验种群,分别对其施加长时间不同强度的干旱胁迫,通过比较黑麦草体内过氧化物酶(POD)、超氧化物歧化酶(SOD)、多酚氧化酶(PPO)活性及其同工酶谱的变化以探讨保护酶系统在内生真菌——植物共生体的抗旱性方面所作的贡献。研究结果表明,水分胁迫和内生真菌对黑麦草3种酶的影响不仅表现在总量上而且表现在同工酶的酶谱及各区带的酶活力上。就总酶活力而言,EI和EF植株中POD、SOD和PPO的活性均随着干旱胁迫强度的增加而增加,进一步将EI和EF植株的酶活力进行比较,发现与EF植株相比,EI植株中POD和PPO的活性相对较低,而SOD的活性相对较高。从同工酶的谱带数量和强弱来看,POD同工酶各区带活力均随干旱胁迫强度的增加而增加,EI植株叶片增加的幅度高于EF叶片,而且EI叶片在重度胁迫下出现了1条新带SOD同工酶各区带活力在EI叶片中有随干旱胁迫增加而增加的趋势,而在EF叶片中有些区带酶活力增强,有些区带酶活力减弱,且EI叶片在中度胁迫下出现了1条新带;PPO同工酶随干旱胁迫的增强,EI和EF叶片均表现为有些区带酶活力增强,有些区带酶活力减弱。总之,内生真菌的感染虽然没有显著提高宿主植物黑麦草POD、SOD和PPO的活性,但使宿主黑麦草对干旱胁迫的反应更为迅速,其中既包括POD、SOD等酶活力的迅速升高,也包括新酶带的产生。     

文心兰原球茎形态发生与可溶性物质及抗氧化酶的关系

以文心兰切花品种'南茜'无菌苗为材料,取其茎尖通过组织培养诱导形成原球茎和幼苗,观察并分析了原球茎各形态发生阶段的特征及其可溶性糖和蛋白质含量、抗氧化酶(POD、CAT和SOD)活性以及相关同功酶(POD、EST和SOD)的变化.结果显示:(1)文心兰原球茎形态发生可分为外植体期、外植体膨大期、愈伤组织期、原球茎形成期、原球茎成熟期、叶鞘伸展期、顶端腋芽发育期及幼苗期8个阶段.(2)可溶性糖和蛋白质含量均在叶鞘伸展期出现最大峰值;POD活性在外植体膨大期、CAT和SOD活性在愈伤组织期分别出现最大峰值.SOD同工酶的2条酶带在愈伤组织期到幼苗期交替出现;EST同工酶在原球茎形成期有2条特异酶带.研究表明,可溶性糖和蛋白质的含量以及POD、CAT、SOD活性的特异变化与文心兰茎尖脱分化及原球茎再分化的实现密切相关,不同类型的同工酶在原球茎同一发生阶段表现出较大差异,EST同工酶的2条特异酶带可作为原球茎形成的标志.     

小叶锦鸡儿抗沙埋生长与抗氧化酶及同工酶变化的关系

小叶锦鸡儿(Caraganas tenophylla L.)是广泛应用于流动沙丘治理的优良固沙植物。然而关于其抗沙埋生理机理目前尚不清楚。选择生长在科尔沁沙地的小叶锦儿为试验材料,依据株高对其进行不同程度沙埋(轻度、中度、重度沙埋), 并通过测定沙埋过程中植株高度、不同部位叶片丙二醛(MDA)含量、抗氧化酶活力、抗氧化酶同工酶谱变化, 以揭示其抗沙埋生理适应机理和基因调控机理。结果表明:沙埋6d,植株各部位生长加快,尤其是顶部和基部生长更快。叶片MDA含量降低、整株植物叶片平均过氧化氢酶(CAT)、过氧化物酶(POD)、过氧化物歧化酶(SOD)活力增加,但重度沙埋使抗氧化酶活力下降。沙埋12d,植株各部位生长继续加大, 沙下叶片凋落。与对照相比,沙上叶片MDA含量成倍增加,并与叶片POD、SOD和CAT活力的大幅度提高呈正相关,并与对照差异显著(P < 0.01)。同时,不同厚度沙埋6d,叶片CAT同工酶出现两新带CAT III和CATII;POD同工酶谱带(6条酶带)随沙埋厚度增加,叶片PODII区带加宽、色加深,POD I 和POD III酶带消失。但是,不同厚度沙埋下,沙上和沙下叶片CAT、SOD和POD酶谱带数和活力均相同。这表明在沙埋应激适应反应期(6d),叶片抗氧化酶活力的增强与抗氧化酶基因表达增强和基因启动有关。受到沙埋重力胁迫的成熟叶可能将胁迫信号传递给沙上没有沙埋的叶子及生长点,导致整株叶片产生整体适应性反应,激活抗氧化酶系统,以致加速生长。因此,小叶锦鸡儿萌蘖生物学特性和抗氧化酶对沙埋胁迫快速响应在维护氧自由基代谢平衡和植株快速恢复生长中起重要保护作用。     

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.