5-羟色胺转运体基因异体表达模型的建立

目的:探讨建立5-羟色胺转运体(5-HTT)基因异体表达模型的可行性,且为进一步探讨5-羟色胺重摄取的动力过程和条件以及其功能的调控机制奠定基础.方法:利用体外转录cRNA技术将克隆至pOTV中的5-HTT的cDNA转录、合成5HTT的cRNA,通过显微注射技术将该cRNA注入成熟雌性非洲爪蟾卵母细胞的胞质中,使其表达以建立5-羟色胺转运体(SERT)的异体表达模型,并用电压钳技术检测其转运功能.结果:爪蟾卵母细胞可被用做5-HTT的异体表达模型,其转运功能呈浓度依赖性并具饱和现象,转运过程可被特异阻断剂Desipramine阻断.结论:非洲爪蟾卵母细胞可作为5-羟色胺等单胺类神经递质转运体的异体表达系统,为进一步研究转运体蛋白的功能和调控提供了有效工具.     

中华大蟾蜍卵母细胞质膜的外向整流型钾离子通道

我们用电压箝方法研究了中华大蟾蜍卵母细胞的膜生理特性。发现卵母细胞膜去极化至-30mV及更偏正时,有一持续的外向电流出现,该电流与去极化程度约呈正比增加,当膜电位箝在20mV时其峰值达3.7±1.4μA。该电流被钾离子通道拮抗剂TEA和4-AP抑制,TEA半抑制浓度为2.6mmol/L。氯通道拮抗剂9-AC(2.5mmol/L)无抑制作用。无钙的或钙离子浓度增加三倍的胞外灌流液均对该电流无影响、该外向电流的逆转电位随胞外钾离子浓度的改变而变化。胞外钾离子浓度增加十倍,逆转电位约增加47.3mV,而胞外钠、钙或氯离子浓度的改变对逆转电位基本上无影响,因此该电流可被认为主要是电压依赖性钾离子流。取自冬眠蟾蜍的卵母细胞经孕酮诱发成熟后,电压依赖性钾离子流减小,仅为原来的1/20-1/30,而取自全年在高温饲养的蟾蜍的卵母细胞经孕酮处理后未见成熟,其电压依赖性钾离子流仅减小至原来的三分之一。     

5—羟色胺抑制离体脊髓运动神经元的突触传递

应用新生大鼠脊髓切片运动神经元(MN)细胞内记录技术,发现5-羟色胺(5-HT)10～100μmol/L灌流可浓度依从地抑制背、腹根刺激在MN诱发的兴奋性突触后电位(EPSP)和抑制性突触后电位,但可增大外源性谷氨酸引起的MN去极化。5-HT对背根性EPSP的抑制无刺激频率依赖性,可为5-HT_(1A)受体激动剂8-OH-DPAT模拟,但不受士的宁、酮色林及MDL 72222的影响。结果表明5-HT可直接激活初级传入纤维末梢5-HT_(1A)受体而抑制MN的突触传递。     

力竭运动及恢复期大鼠纹状体5-HT、DA及其代谢物浓度的动态变化研究

目的:观察一次性力竭运动过程及恢复期大鼠纹状体细胞外液中多巴胺(DA)和5-羟色胺(5-HT)及其代谢物浓度的动态变化规律。方法:采用活体微透析结合毛细管电泳-激光诱导技术,连续观察清醒大鼠在一次性力竭运动过程及恢复期纹状体细胞外液中酪氨酸(Tyr)、5-HT、5-羟吲哚乙酸(5-HIAA)、色氨酸(Trp)和DA浓度的动态变化。结果:大鼠纹状体细胞外液中Trp、5-HT、5-HIAA水平运动初期均未见显著变化(P>0.05),运动后期、力竭及恢复期均显著高于安静水平(P<0.05,P<0.01);DA、Tyr水平在运动后期、力竭及恢复期显著高于安静水平(P<0.05,P<0.01);DA/5-HT运动初期显著升高(P<0.05,P<0.01),运动后期出现下降趋势,力竭前15 min降至最低点,而恢复期略有回升,但运动后期、力竭及恢复期与安静状态相比均无显著差异。结论:力竭运动过程中大鼠纹状体细胞外液中DA和5-HT的动态变化具有阶段性特征,运动疲劳过程中状体内DA和5-HT两种神经递质的代谢水平均显著增强,而其中以5-HT的作用占优。     

针刺对血和脑色氨酸浓度的影响

已知色氨酸是脑内5-羟色胺(5-HT)生物合成的前体,由血液转运入脑,但它在脑内的浓度低于色氨酸羟化酶(Tryptophan Hydroxylase)亲和力所需要的浓度。本文作者已证实,5-HT 能系统的正常功能是实现针刺镇痛的必需条件,针刺过程能激发脑内5-HT 能神经元的活动,使5-HT 生物合成增加,它的代谢产物5-羟吲(?)醋酸(5-HIAA)明显升高。那么,针刺镇痛过程是否也激发血脑色氨酸的转运功能,以保持脑内5-HT 能神经元正常活动的需要。本文针对这问题,在针刺镇痛后,分别测定血和脑色     

胞外钙对豚鼠耳蜗Deiters细胞钾电流的调制

为观察胞外钙对豚鼠耳蜗单个离体Deiters细胞钾电流的调控作用并探讨其机制,实验记录了Deiters细胞在正常细胞外液和无钙外液中的全细胞钾电流(whole cell K^ currents,IK),并分析了其电生理学特性的改变。结果观察到,Deiters细胞与在正常细胞外液中相比,在祛除细胞外液中的Ca^2 后Ik电流幅值明显增加,弦电导值亦明显增加,但其平衡电位未明显改变。在无钙外液中Ik电流的反转电位向超极化方向明显移位,更接近于按照Ner-nst方程得出的K^ 理论平衡电位;而且其稳态激活曲线亦向超极化方向明显移位,但其激活趋势与正常相比无明显改变。此外,观察了Deiters细胞中钙抑制性钾电流的电流-电压关系和电导-电压关系,发现两者均呈“S”形,提示此钙抑制性钾电流可能存在2种不同的钾电导成分。由此,推测可能有两种机制参与胞外钙对Deiters细胞钾电流的调控：(1)Deiters细胞中的Ik通道可能存在一个Ca^2 敏感结构域,胞外Ca^2 可能通过改变此结构域而对Ik电流产生调制;(2)Deiters细胞中可能存在一种新型的双相门控性钾通道或钾通道耦联型受体或是一种新型的钾通道亚型,祛除胞外Ca^2 可激活此新型钾电导而对L电流产生调制。由此推测,在听觉形成过程中,胞外钙浓度下降可以对Deiters细胞的全细胞钾电流产生调制,从而更有利于Deiters细胞内K^ 外流,进而有效地缓冲外毛细胞周围的K^ 浓度：而且还可以使Deiters细胞产生更快的复极化并有利于维持其静息状态。     

5—羟色胺介导的豚鼠肠系膜下神经节突触传递

本实验通过豚鼠离体肠系膜下神经节(IMG)的细胞内生物电记录方法观察到:(1)5-羟色胺(5-HT 1-100μmol/L)灌流可在部分 IMG 细胞引起与非胆碱能迟慢兴奋性突触后电位(Is-EPSP)相似的缓慢去极化;(2)持续灌流5-HT 可使对5-HT 敏感的 IMG 细胞的Is-EPSP 明显阻抑;(3)5-HT 去极化及5-HT 敏感细胞的 Is-EPSP 均可为5-HT 再摄取抑制剂氟苯氧丙胺(50μmol/L)所增大,而对5-HT 不敏感细胞的 Is-EPSP 则不受这种药物的影响,(4)5-HT 合成抑制剂对氯苯丙氨酸(PCPA)预处理可使 IMG 细胞的 Is-EPSP 的出现率和去极幅度均明显减低。上述结果表明:5-HT 可能参与介导豚鼠部分 IMG 细胞的Is-EPSP。     

P物质对大鼠三叉神经节神经元GABA-和5-HT-激活电流的反向调制作用

实验采用全细胞膜片钳技术观察P 物质(SP)对大鼠同一三叉神经节(TG)神经元γ-氨基丁酸激活电流(IGABA)和5-羟色胺激活电流(I5-HT)的调制作用。在受检的47 个 TG 细胞中,多数情况下可在同一细胞记录到IGABA 和 I5-HT 两种电流(63.8%,30/47)。在 30 个同时对 GABA 和 5-HT 敏感的细胞,其中 22 个细胞预加 SP(0.01 μmol/L)后,IGABA 减小(35.7 ± 6.1)%,而I5-HT 增加(65.2 ±8.7)%。此种调制作用可被SP 受体拮抗剂GR82334 及胞内透析GDP-β -S 或GF109203X 所阻断。以上结果表明:SP 受体激活后经G 蛋白耦联,通过相同的PLC-DAG-PKC 转导途径对同一感觉神经元共存的GABAA 受体和5-HT3 受体产生相反的调制效应。     

儿童强迫症、抑郁症患者血小板5-羟色胺浓度的比较研究

目的:通过检测儿童强迫症、抑郁症患者血小板5-羟色胺(5-HT)的浓度,探讨血小板5-HT在儿童强迫症、抑郁症发病中的作用.方法:采用高效液相色谱法检测22例强迫症患儿(包括强迫思维15例,强迫动作7例)和20例抑郁症惠儿血小板5-HT的浓度,并与20名正常儿童进行比较.结果:强迫症患儿(173.43±90.67)ng/109和抑郁症患儿(251.62±152.72)ng/109血小板5-HT的浓度低于正常儿童(351.91±170.97)ng/109(P<0.05),强迫症患儿的血小板5-HT的浓度和抑郁症惠儿的差异没有显著性(P>0.05).强迫症患儿中,强迫思维惠儿的血小板5-HT的浓度(147.09±44.92)ng/109低于强迫动作患儿(229.88±1:136.44)ng/109(P<0.05).结论:儿童强迫症、抑郁症患者血小板5-HT浓度明显下降,并且强迫思维患儿的血小板5-HT浓度与强迫动作患儿的差异有显著性.     

钙、钠离子对心房 T 波(Ta 波)的影响

本文用心电图记录离体豚鼠灌流心脏。提高灌流液中钙的浓度(由2.5分别提高到4.0、6.0、8.0和10.0mEq/L),导致全部的 Ta 波振幅降低,P—aTa 间期缩短。Ta 波的形态由正常时的“帐蓬形’变为“钝角形”。然而,降低灌流液中钙的浓度(由2.5降至2.0、1.2和0mEq/L)引起的相反变化,即 Ta 波振幅增加和 P—aTa 间期延长。另一方面,降低灌流液中钠的浓度(由143分别降至133、123和113mEq/L)出现 Ta 波振幅降低,但当提高灌流液中钠浓度时,所观察标本仅50%出现 Ta 波振幅升高。这提示,豚鼠心房肌对高钠浓度不如对低钠浓度敏感。T 波的变化可能是由于钠浓度改变的结果。     

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.