羊草细胞变异系HR20－8的氨基酸组成水平与脯氨酸含成代谢变化的研究

离体培养,筛选获得羊草（Ａｎｅｕｒｏｌｅｐｉｄｉｕｍｃｈｉｎｅｎｓｅ（Ｔｒｉｎ．）Ｋｉｔａｇ．）抗羟脯氨酸（ＨＹＰ）细胞变异系ＨＲ２０－８,其愈伤组织中游离氨基酸和蛋白质氨基酸含量均发生了较大的变化,与供体对照比较,分别提高２．３５倍和１．４０倍,其中的脯氨酸组分在变异系体内表现异常增加,游离和蛋白质中的脯氨酸组分分别提高６．６倍和３．０倍,对脯氨酸合成途径中的γ－谷氨酸激酶的特性分析表明,变异系ＨＲ２０－８细胞内γ－谷氨酸激酶的活性比供体提高２．５倍。     

甘蔗抗逆细胞系选择及其生化特性的研究

利用脯氨酸类似物羟脯氨酸(Hyp)的生长抑制作用,筛选出抗Hyp的甘蔗(Saccha-rum sinensis Roxb)细胞变异系R932。抗性系体内游离脯氨酸含量超常积累(×3．2)。而且其体内脯氨酸合成途径中的关键酶γ－谷氨酸激酶对脯氨酸的反馈抑制较不敏感。R932抗PEG和低温能力较供体加强。实验结果表明γ－谷氨酸激酶特性的变化可能导致细胞内脯氨酸的过量积累,脯氨酸的过量积累有利于植物细胞对抗恶劣环境。     

枸杞抗羟脯氨酸细胞变异系筛选及其耐盐特性的研究

试验以枸杞(Lycium barbarum L.)成熟胚诱导的胚性愈伤组织为材料研究了：(1)^60Co—γ射线诱变处理对愈伤组织的影响;(2)耐羟脯氨酸(HYP)愈伤组织变异系的筛选;(3)耐HYP愈伤组织变异系的耐盐性及稳定性分析;(4)耐HYP愈伤组织变异系生理生化特性;(5)变异系的分化和再生苗的生理生化特性。初究结果表明：由胚性愈伤组织经30Gy的^60Co—γ辐射处理,在含16mmol／L HYP选择培养基和无HYP培养基上交替培养4代,分离出耐HYP的愈伤组织变异体;该变异体游离脯氨酸含量比对照高3．3倍,其再生植株叶片游离脯氨酸比对照高13．5倍。     

羊草细胞变异系HR20—8的氨基酸组成水平与脯氨酸合成代谢变化的…

离体培养,筛选获得羊草抗羟脯氨酸细胞变异系ＨＲ２０－８,其愈伤组织中游离氨基酸和蛋白质氨基酸含量均发生了较大的变化,与供体对照比较,分别提高２．３５倍和１．４０倍,其中的脯氨酸组分在变异系体内表现异常增加。     

葡萄耐羟脯氨酸变异细胞系的筛选及其特性研究（简报）

葡萄愈伤组织经甲基磺酸乙酯（EMS）诱变处理后,用羟脯氨酸（HMP）作为选择压力,筛选出耐HYP的变异细胞系。该变异系游离脯氨酸含量比正常细胞系高4．7倍,并且表现出很强的耐NaCl和PEG能力。在盐胁迫下,变异系吸收的K 和Na 含量均高于正常系,而K ／Na 比值仍与正常系相近。     

红豆草抗羟脯氨酸变异系的筛选及其特性研究

通过选择-NaN_3诱变处理-再选择的程序从红豆草下胚轴愈伤组织获得了抗脯氨酸类似物L-羟脯氨酸的变异细胞系。抗性变异细胞系的游离脯氨酸含量比正常细胞系高4.6倍,并且抗性变异系亦表现出了很强的耐NaCl、PEG 能力。这可能为筛选抗逆境植物提供一条有效途径。     

抗羟脯氨酸水稻变异系的筛选及其特性的研究

利用Hyp反复筛选经EMS处理的水稻愈伤组织,得到4个抗性细胞系。它们的游离脯氨酸含量高于对照2—25倍。Hyp(2 mmol/L)和NaCl(1%)胁迫对M_1、M_2变异系γ-谷氨酰磷酸合成活力及游离脯氨酸积累的影响呈一定的正相关性。变异系在0.8%,15NaCl 培养基中分化出植株。与对照相比,各变异系在愈伤组织、植株水平上均表现较强的耐盐性,且与游离脯氨酸的积累量呈正相关。     

单倍性烟草Hyp抗性愈伤组织变异系的选择及其生理生化特性的研究I．Hyp抗性变异系的抗性表现

利用多步正筛选系统,对⁶⁰C0Y射线诱变的单倍性体细胞愈伤组织无性系经过连续八轮的分离与选择,获得了抗脯氨酸类似物Hyp(L－羟基脯氨酸)的烟草愈伤组织变异系C^r-2,H^r-4和X^r-1,并由之再生出了相应的抗性植株。离开选择压力的Hyp抗性变异体愈伤组织系、再生植株及其次生愈伤组织均具抗Hyp的抑制作用。变异系对苏氨酸的抑制作用不表现交叉抗性。在Hyp抑制培养基上,变异体小植株的发根能力高于其野生型。离开选择剂转代培养了七代的变异系对Hyp的抑制作用仍保持着相对稳定的抗性。     

单倍性烟草Hyp抗性愈伤组织变异系的选择及其生理生化特性的研究Ⅱ．Hyp抗性变异系内游离脯氨酸的积累

在正常条件下,烟草Hyp抗性变异系愈伤组织内的游离脯氨酸含量是其野生型的4倍多。这种积累游离脯氨酸的特性在愈伤组织的转代、再生及次生过程中均十分稳定。虽然其他多种氨基酸含量也有所改变,但变异系内游离脯氨酸的积累具有特异性。由于脯氨酸对Hyp抑制效应具有部分的逆转作用,所以游离脯氨酸的积累是变异系抗Hyp抑制作用的重要原因。然而,变异系内蛋白质组成中的脯氨酸并没有特异性地增加。在Hyp存在条件下,变异系内的硝酸还原酶、转化酶及过氧化氢酶活性均显著地高于野生型。表明变异系对培养基中的碳源和氮源具有较高的利用能力。     

单倍性烟草HyP抗性愈伤组织变异系的选择及其生理生化特性的研究Ⅲ．Hyp抗性变异系在逆境条件下的反应

在水分胁迫、盐分胁迫、抑制剂胁迫和⁶⁰C0 γ-射线等逆境条件下,烟草愈伤组织系中的游离脯氨酸含量随着逆境胁迫程度的增加而幅度不同地提高。在一定范围内,二者之间存在着特定的正相关。在正常条件下积累游离脯氨酸的烟草Hyp抗性愈伤组织变异系C^r-2虽在耐寒能力方面并不比其野生型C^w高,但对盐分逆境和模拟干旱处理的抗性均是其野生型的两倍多。烟草Hyp抗性愈伤组织变异系在研究抗旱和抗盐中具有潜在的应用价值。     

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.