水胁迫下沙漠小球藻蛋白质组学分析

通过研究小球藻(Chlorella sp.)在干旱胁迫下的蛋白质组变化,从蛋白质表达水平解释小球藻对干旱胁迫的响应机理。以20%的PEG 6000胁迫处理0、6、12、18、24和30 d,提取小球藻总蛋白,利用双向电泳和质谱鉴定技术分析差异蛋白。共鉴定29个差异蛋白,按功能可分为7类:光合作用、能量合成和转化、物质代谢、抗氧化、转运和细胞结构、抗逆和功能未知蛋白质。这些蛋白的表达变化影响着沙漠小球藻的油脂积累,对干旱胁迫应答起到了至关重要的作用,并直接或间接地参与了沙漠小球藻细胞内的光合作用和油脂合成。     

高温强光胁迫对苹果果皮PPO活性的影响

苹果果实日烧是一种普遍发生的生理病害,最常见的特征之一就是在果实表面出现褐变。通常认为PPO与植物的酶促褐变密切相关。研究了自然和控制条件下,高温强光胁迫对果实PPO活性的影响,以便揭示高温强光胁迫下苹果果实褐变与PPO活性之间的联系。结果表明：高温和强光胁迫与果皮PPO活性变化密切相关。就树冠不同方位而言,西南方位是高温和强光胁迫最严重的区域,其外围裸露果实的PPO活性也最强。在一定范围内,随着处理温度和光照强度的升高,果皮PPO活性也逐渐增强。短时间剧烈升温能够引起PPO活性骤然上升。在同样程度的高温胁迫下,提高环境湿度有利于抑制果皮PPO活性,从而减轻褐变症状的发生。室内外试验一致证实：果实日烧褐变现象与高温强光胁迫下果皮组织PPO活性大幅度提高有直接关系。     

合浦珠母贝海洋酸化和温度胁迫下基因共表达网络分析

利用共表达网络分析法(WGCNA)筛选出合浦珠母贝外套膜在高温胁迫下影响显著的1个响应基因模块和海水酸化胁迫下的5个响应基因模块,并对模块中包含的基因进行功能富集;分析贝壳蛋白与模块其他基因的关联性,构建矿化基因的应激网络。高温显著响应模块基因富集结果显示细胞骨架蛋白发生了显著的变化,如ARHGEF4、SAP和myosin。酸化应答模块共5个,响应的基因包括呼吸相关的血红素A合成酶、芳香族氨基酸代谢相关的酶、钙粘蛋白和血小板反应蛋白等。另外,高温应答模块聚集了最多矿化基因,包括MSI、Tyrosinase、Fibronectin-like protein等重要的矿化基因,说明这些矿化基因对温度较为敏感。构建基因共表达网络的结果显示钙离子结合蛋白、细胞骨架蛋白、蛋白质糖基化相关的基因关系密切。     

干旱胁迫下蒙古沙冬青叶片蛋白质组学研究

通过对蒙古沙冬青[Ammopiptanthus mongolicus(Maxim)Cheng.f]叶组织干旱胁迫下蛋白质组变化的研究,从蛋白表达水平阐释其应答干旱胁迫的分子机制。以20%PEG 6000胁迫处理1 h和72 h,以0 h为对照,提取叶片总蛋白,利用双向电泳和质谱鉴定技术分析差异表达蛋白。共鉴定了40个差异表达蛋白,按功能可分为9类:光合作用,ROS清除,蛋白的合成、加工与降解,物质运输,防御相关,RNA加工,氨基酸代谢,其他相关蛋白和功能未知蛋白质。蒙古沙冬青叶片应答干旱胁迫的核心是叶绿体结构和光合作用的维持。     

日灼胁迫对枇杷果皮蛋白质组的影响

为了探讨枇杷果皮响应日灼胁迫的差异表达蛋白的变化,以日灼抗性弱的‘金钟’枇杷和日灼抗性较强的‘红猴本’枇杷为研究对象,将处于转色期的枇杷果实在40 ℃下日灼处理90 min,果皮蛋白采用双向电泳分离和MALDI TOF/TOF MS进行鉴定。结果显示：（1）日灼后枇杷果皮中有64个表达丰度在2倍以上的差异蛋白,其中56个蛋白被成功鉴定,且38个在‘金钟’中表达,23个在‘红猴本’中表达。（2）这些蛋白质参与胁迫响应和防御（30.3%）、光合作用（14.3%）、呼吸作用（25.0%）、蛋白质代谢（14.3%）等生理过程。（3）相对于‘红猴本’枇杷,‘金钟’枇杷果皮细胞中多种热激蛋白（HSP）的含量上升,参与呼吸作用的蛋白含量增加以产生更多的能量,但是大部分与光合作用相关的蛋白含量下降,清除活性氧（ROS）酶如抗坏血酸过氧化物酶（APX）和多酚氧化酶（PPO）含量降低,同时PPO酶活性下降。研究表明,要提高枇杷果皮抗日灼性可能需要提高清除ROS酶的含量和活性,需要一定量的HSP,以及保持正常的呼吸作用和光合作用。     

利用蛋白质组学技术揭示的植物高温胁迫响应机制

高温是限制植物生长和产量的主要非生物胁迫因子.近年来,蛋白质组学研究为我们从系统生物学水平深入认识植物高温胁迫应答的复杂的分子机制提供了重要信息.目前,已经分析了模式植物拟南芥、主要粮食作物(大豆、水稻和小麦)、耐热植物(匍匐剪股颖、马齿苋、假虎刺),以及野生毛葡萄、胡杨、苜蓿、半夏等应答高温胁迫过程中的蛋白质组变化特征.这些研究共鉴定到838种响应高温胁迫的蛋白质,其中534种蛋白质表达受到高温诱导,304种蛋白质表达受到抑制.本文整合分析了上述植物在应对不同程度高温胁迫(30～45 ℃处理0～10 d)时蛋白质表达模式的变化特征,为解释高温胁迫应答网络体系中重要的信号与代谢通路(如：信号转导、胁迫防御、糖类与能量代谢、光合作用、转录、蛋白质合成与命运、膜与转运等)的变化提供了证据和线索,为深入认识植物应答高温胁迫的分子调控机制奠定了坚实的基础.     

番茄钙依赖性蛋白激酶基因LeCPK2在热(光)胁迫中的功能鉴定

钙依赖性蛋白激酶(calcium-dependent protein kinases,CDPKs or CPKs)作为一类钙感知蛋白在植物的生长发育和胁迫应答中起着重要的作用.LeCPK2 (GenBank accession No.:GQ205414)是我们从番茄中分离的第3个CDPK基因,前期研究表明LeCPK2可能在植物热胁迫应答中发挥作用.为了进一步研究其在热胁迫中的功能,我们通过电子克隆的方法分离了LeCPK2的启动子序列,并通过LeCPK2过表达烟草分析其在高温胁迫中的潜在的功能.生物信息学分析显示,LeCPK2启动子中包含5个热响应元件,和前期试验结果一致.野生型植株在受到热胁迫后,对光更为敏感,强光照下植株叶片发生萎蔫,而强光本身不会对未受热胁迫的健康植株造成伤害.LeCPK2转基因植株热、光胁迫后不会出现受害表型.以上研究表明,LeCPK2在植物的热胁迫应答中发挥重要作用,能够有效保护植株免受高温胁迫的损害,是一个优秀的耐热(光)基因.本研究将为揭示番茄LeCPK2遗传功能及对其开发利用奠定基础.     

水杨酸对高温强光下小麦叶绿体蛋白酶Deg5和PSⅡ功能的调节作用

以小麦(Triticum aestivum)矮抗58为材料,采用0.1mmol/L的外源水杨酸(SA)处理小麦叶片,以清水为对照,通过Western blotting蛋白质印记技术和叶绿素荧光分析,研究了高温强光胁迫(38℃和1600μmol m-2s-1)对小麦叶绿体Deg5蛋白酶、D1蛋白和叶绿素荧光参数的影响及SA的调节作用。结果表明,高温强光胁迫导致小麦叶绿体Deg5蛋白酶、D1蛋白含量和PSⅡ最大光能转化效率(Fv/Fm)降低,原初荧光(Fo)升高。和对照相比,外源SA处理可维持较高的Deg5蛋白酶、D1蛋白、Fv/Fm水平和较低的Fo。说明外源水杨酸可减轻高温强光对Deg5蛋白酶和D1蛋白的损伤,维持较强的PSⅡ功能。     

水杨酸对高温强光胁迫下小麦叶绿体基因psbA表达的调节

以0.1、0.3和0.5mmol.L^-1的水杨酸预处理灌浆期的小麦叶片,测定在高温强光胁迫下小麦叶绿体基因psbA表达、D1蛋白含量和PSII功能。结果表明,叶面喷施SA不仅可减缓高温强光对psbA表达的抑制,而且可促进胁迫后在适宜光温条件下恢复表达的水平。     

酸胁迫下短乳杆菌NCL912蛋白质的差异表达及其作用

【目的】本文从蛋白质组水平,对本实验室分离的一株高产γ-氨基丁酸的短乳杆菌NCL912(Lactobacillus brevis)在酸胁迫下蛋白质的差异表达及其应激机理进行探讨。【方法】利用双向凝胶电泳技术对pH 5.0和pH 4.0条件下,不含L-谷氨酸钠的培养物的蛋白质组电泳图谱进行了分析,并对酸胁迫下差异表达的蛋白进行了比较。利用质谱检测技术和生物信息学技术对这些差异表达的蛋白进行了鉴定、功能分类和代谢途径分析等。【结果】通过双向凝胶电泳技术,可以得到均匀、背景清晰、分辨率高、重复性好的Lb.brevis NCL912的双向凝胶电泳图谱。对pH 5.0和pH 4.0条件下培养的该菌总蛋白质电泳图谱进行比较,发现有25个差异表达的蛋白点。对这25个差异表达的蛋白进行了质谱鉴定。由于缺乏短乳杆菌NCL912的全基因组,所以其中只有8个蛋白点被质谱鉴定和分析得到。它们分别参与了蛋白质的合成、核苷酸的合成、糖酵解代谢、细胞能量水平的调节等。【结论】酸应激下这些表达蛋白质可通过其相应的功能来保护细胞耐受酸胁迫,从而使菌能够在酸性环境下生存增值。这可能就是Lb.brevis NCL912的酸胁迫应激机理之一。     

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.