人胎儿胸腺内bc1－2基因表达与分布

采用免疫酶组织化学与地高辛标记的单链ｃＤＮＡ探针原位杂交技术,研究了抗凋亡基因ｂｃｌ－２在人胎儿胸腺组织中的表达与分布。结果ｂｃｌ－２ｍＲＮＡ及其蛋白均优势定位于髓质区。提示胸腺中ｂｃｌ－２基因表达调控发生在转录水平;ｂｃｌ－２基因介导的细胞凋亡状态可能参与Ｔ淋巴细胞的成熟过程。     

小鼠成纤维细胞凋亡过程中P53与bcl-2表达的时序性

为探讨细胞凋亡过程中,ｂｃｌ－２与Ｐ５３,这两种凋亡关键性基因的相互关系,用５－氟尿嘧啶（５－Ｆｕ）诱导小鼠正常与恶性转化的成纤维细胞的凋亡,观察了这两种基因在凋亡过程中表达变化的时序．经流式细胞计检测,这两种细胞在５－Ｆｕ作用２４ｈ均出现了凋亡峰,细胞存活率随之下降,ＤＮＡ电泳显现梯状断裂．Ｎｏｒｔｈｅｒｎ杂交结果显示,在５－Ｆｕ作用６ｈ后两种细胞Ｐ５３ｍＲＮＡ水平已明显增高,而ｂｃｌ－２ｍＲＮＡ水平则在作用１２ｈ方明显降低．Ｐ５３上调与ｂｃｌ－２下调的明显时序性,说明Ｐ５３具备作为ｂｃｌ－２基因负调控转录因子的条件．由此,为进一步了解凋亡过程的ｂｃｌ－２基因下调机理提供了线索     

细胞凋亡过程中bcl-2基因的甲基化

为探讨凋亡过程中,ｂｃｌ－２基因下调与该基因甲基化状态的关系,用５－氟尿嘧啶（５－Ｆｕ）诱导小鼠成纤维细胞ＮＣ３Ｈ１０,ＴＣ３Ｈ１０及人乳腺癌细胞ＭＣＦ－７的凋亡,分别检测了这三种细胞凋亡过程中ｂｃｌ－２的表达变化,与其调控区及编码区的甲基化状况．我们曾观察到５－Ｆｕ作用２４～４８ｈ出现细胞存活率下降,ＤＮＡ梯状断裂及细胞周期凋亡峰显现等典型凋亡现象．Ｎｏｒｔｈｅｒｎ杂交显示,在５－Ｆｕ作用１２ｈ时ｂｃｌ－２ｍＲＮＡ水平已明显降低．由此,我们用小鼠ｂｃｌ－２（ｍｂｃｌ－２）及人ｂｃｌ－２（ｈｂｃｌ－２）基因调控区ＰＣＲ扩增片段及ｂｃｌ－２编码区（ｃＤＮＡ）片段作为探针,与５－Ｆｕ作用１２ｈ的细胞ＤＮＡ的ＭｓｐⅠ／ＨｐａⅡ酶切产物进行Ｓｏｕｔｈｅｒｎ杂交,以未作用的细胞ＤＮＡ同样酶切杂交为对照．通过杂交带谱的变化,分析ｂｃｌ－２基因的甲基化状况．结果显示：ｍｂｃｌ－２及ｈｂｃｌ－２在５－Ｆｕ作用１２ｈ后调控区甲基化水平增高,但其编码区甲基化状态皆未出现可检出的变化．上述结果提示：ｂｃｌ－２基因调控区甲基化水平升高可能与该基因下调有关     

bcl-2癌基因蛋白在鼻咽癌以及单克隆癌细胞裸鼠体内连续传代中的表达

用免疫组织化学Ｓ－Ｐ方法,检测了４０例低分化鼻咽癌、３０例鼻咽癌克隆细胞裸鼠移植瘤、１０例慢性鼻咽炎及８例人胚鼻咽上皮组织石蜡包埋切片中抗凋亡基因ｂｃｌ－２癌蛋白的表达;并进一步检测了鼻咽癌克隆株在裸鼠体内演进中ｂｃｌ－２癌蛋白的表达以及与淋巴结转移之间的关系。结果表明：鼻咽癌及其裸鼠移植瘤组织中ｂｃｌ－２癌蛋白的表达率分别为６２．５％和７０％,慢性鼻咽炎中ｂｃｌ－２癌蛋白的表达率为１０％,人胚鼻咽上皮组织中不表达ｂｃｌ－２癌蛋白,鼻咽癌及其裸鼠移植瘤组织中ｂｃｌ－２癌蛋白的表达率明显高于慢性鼻咽炎组织中（Ｐ＜０．０１）;鼻咽癌克隆株演进中癌细胞ｂｃｌ－２癌蛋白的表达不断升高,其淋巴结转移率亦不断升高。提示：抗凋亡基因ｂｃｌ－２癌蛋白的表达可能和鼻咽癌的发生、演进及转移能力密切相关     

急性白血病细胞中抗凋亡蛋白bcl－2及其mRNA的表达

采用免疫组织化学与原位杂交方法检测了２５例急性髓系或淋巴系白血病骨髓活检组织及６种白血病细胞株中ｂｃｌ－２蛋白及其ｍＲＮＡ水平。结果２１例白血病标本中存在ｂｃｌ－２蛋白及其ｍＲＮＡ的一致性高表达;５种白血病细胞株（ＣＥＭ、Ｒａｊｉ、ＨＬ－６０、Ｕ９３７及Ｋ５６２）均能表达一定水平的ｂｃｌ－２蛋白及其ｍＲＮＡ（Ｍｏｌｔ－４例外）。提示ｂｃｌ－２基因的功能状态与淋巴造血系统肿瘤密切相关。     

双歧杆菌的完整肽聚糖对实验性大肠癌凋亡控制基因表达的影响

为探讨双歧杆菌的完整肽聚糖的抑瘤途径及机制,本文以大肠癌裸鼠移植瘤为动物模型,采用免疫组化ＳＰ法检测了４０只裸鼠移植瘤ｂｃｌ－２及ｂａｘ基因的蛋白表达率及表达强度,结果显示肽聚糖注射组大肠癌移植瘤ｂｃｌ－２蛋白表达率及阳性细胞密度低于肿瘤对照组,ｂｃｘ基因的表达情况则相反。提示双歧杆菌的完整肽聚糖可使大肠癌裸鼠移植瘤的ｂｃｌ－２基因表达下调,ｂａｘ基因表达强,最终诱导肿瘤细胞凋亡,实现其抗瘤目的。     

双歧杆菌的完整肽聚糖对实验性大肠癌凋亡调控基因表达的影响

为探讨双歧杆菌的完整肽聚糖的抑瘤途径及机制,本文以大肠癌裸鼠移植瘤为动物模型,采用免疫组化ＳＰ法检测了４０只裸鼠移植瘤ｂｃｌ－２及ｂａｘ基因的蛋白表达率及表达强度。结果显示完整肽聚糖注射组大肠癌移植瘤ｂｃｌ－２蛋白表达率及阳性细胞密度均低于肿瘤对照组,ｂａｘ基因的表达情况则相反。提示双歧杆菌的完整肽聚糖可使大肠癌裸鼠移植瘤的ｂｃｌ－２基因表达下调,ｂａｘ基因表达增强,最终诱导肿瘤细胞凋亡,实现其抗瘤目的。     

反义bcl—2在胃癌细胞中的诱导表达及促凋亡作用

为了观察ｂｃｌ－２反义ＲＮＡ对胃癌细胞ＳＧＣ７９０１的促凋亡作用及ＭＴ－１１启动子的启动诱导活性,用分子克隆方法构建载体,以电泳术,电镜术,流式细胞术,原位杂交,裸鼠肿瘤抑制试验及化学发光分析等方法观察,结果表明,可诱导载体ｐＭＴｂＮ具有良好的诱导启动转录活性,Ｂｃｌ－２蛋白的表达下降使胃癌细胞ＳＧＣ７９０１更易发生凋亡,致瘤性也发生改变。     

慢性缺氧大鼠肺血管c-myc及bcl-2基因表达研究

应用免疫组织化学和Ｎｏｒｔｈｅｒｎ杂交方法,对慢性缺氧大鼠肺组织（主要是肺血管壁）原癌基因ｃ－ｍｙｃ和抗凋亡基因ｂｃｌ－２表达进行了研究。免疫组织化学观察提示,正常对照组大鼠肺血壁Ｃ－ｍｙｃ和Ｂｃｌ－２蛋白仅为弱阳性或不表达,慢性缺氧１、２周组大鼠肺血管壁这两种抗原表达比对照组显著增强,呈强阳性,Ｎｏｒｔｈｅｒｎ杂交结果表明：慢性缺氧１、２周组大鼠肺组织内ｃ－ｍｙｃ和ｂｃｌ－２的ｍＲＮＡ表达比对照组显著增加,以上结果提示,ｃ－ｍｙｃ及ｂｃｌ－２两种基因调节的细胞增殖与凋亡可能参与了慢性缺氧性肺动脉高压的发病进程。     

核酶对bcl－2mRNA的体外切割

通过微机对ｂｃｌ－２ＲＮＡ二级结构的分析,设计针对ｂｃｌ－２片段５＇ＣＧＣＧＡＣＣＣＧＧＵＣＧＣＣＡＧＧＡＣＣＵＣＧ３＇的“锤头状”（Ｈａｍｍｅｒｈｅａｄ）核酶（Ｒｉｂｏｚｙｍｅ,ＲＤ）基因,平端连接于ｐＧＥＭ－３Ｚｆ（－）ＨｉｎｃⅡ位点,克隆后经测序表明序列正确,ｂｃｌ－２和Ｒｉｂｏｚｙｍｅ基因经体外转录,５０℃作用２ｈ,从１６５６－１６５７（Ｃ－Ｇ）位之间切断ｂｃｌ－２ＲＮＡ片段．     

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.