镉中毒大鼠睾丸与肝脏金属硫蛋白表达的时相研究

啮齿目动物睾丸对镉毒性较肝脏更敏感.为阐明睾丸的镉毒性分子机制,比较了肝脏与睾丸金属硫蛋白（MT）表达的时相变化.mRNA采用RT-PCR技术分析并用光密度扫描定量;蛋白质定量用ELISA方法.结果显示,睾丸中存在MT,镉中毒后MT1与MT2 mRNA明显升高,但MT没有相应增加;肝脏镉中毒后MTmRNA与MT均明显升高.结果提示：镉虽然能诱导睾丸MTmRNA的转录,但没有促进其MT的合成,这可能是睾丸对镉毒性与致癌作用较肝脏更敏感的重要原因.     

黄芪对镉致大鼠睾丸支持细胞超微结构及波形蛋白、E-钙粘蛋白表达改变的保护作用

目的 探讨黄芪对镉致大鼠睾丸支持细胞损伤的保护作用.方法 21只成年雄性SD大鼠随机分成镉组(0.1％氯化镉腹腔内注射,1mg/Kg体重/天,5天/周,处理后1、2、3、4周取材)、镉加黄芪组(注射氯化镉的同时注射黄芪,10g/Kg体重/天,5天/周,处理后2、4周取材)和对照组(腹腔内注射等量生理盐水).睾丸取材作光镜、免疫组织化学染色和图像分析及超微结构观察.结果 光镜H.E染色对照组支持细胞核不规则,染色浅,核仁明显,镉处理后胞浆内有空泡形成,镉加黄芪组支持细胞未见明显改变.对照组波形蛋白阳性产物在支持细胞靠近基室腔的胞浆中表达,E-钙粘蛋白阳性产物则主要定位于生精上皮近腔室的支持细胞和部分生精细胞胞浆中.镉处理后支持细胞胞浆中波形蛋白和E-钙粘蛋白阳性产物表达的平均光密度值均明显降低(P＜0.05),镉加黄芪组阳性产物表达虽较对照组减弱但明显高于相应镉组(P＜0.05).镉处理组支持细胞胞质特化区和紧密连接破坏,镉加黄芪组支持细胞超微病变较相应镉组为轻.结论 镉降低大鼠睾丸支持细胞波形蛋白和E-钙粘蛋白的表达并造成支持细胞的超微结构损伤,黄芪具有较好的保护效果.     

2.45GHz微波辐照后小鼠睾丸Caspase-3 mRNA及凋亡变化的研究

目的:研究2.45GHz微波辐照对小鼠睾丸Caspase-3表达及细胞凋亡诱导作用.方法:采用平均功率密度为65mW/cm2和90mW/cm2的2.45GHz微波辐照小鼠15min,分别于相应时相点取材,采用RT-PCR的方法检测Caspase-3的mRNA表达,用TUNEL方法观察计数睾丸内细胞的凋亡情况.结果:65mW/cm2及90mW/cm2辐照后Caspase-3 mRNA均出现表达升高,65mW/cm2组于12h时达高峰.90 mW/cm2组在24h时达到高峰,90 mW/cm2升高幅度高于65 mW/cm2组;TUNEL结果显示受到微波辐照后,两组小鼠睾丸内均出现凋亡细胞或小体数量增加,但两组之间不存在显著差异.结论:2.45GHz微波能显著促进小鼠睾丸组织Caspase-3 mRNA的表达,存在时效和量效依赖关系;2.45GHz微波能显著诱导小鼠睾丸内细胞凋亡,存在时间依赖性.     

大鼠睾丸镉毒性相关蛋白质组学研究

镉是对动物与人的生殖系统均具有毒性的环境污染物。为深入系统地探讨镉毒性机制,应用二维电泳与质谱联用技术对镉暴露大鼠睾丸组织蛋白表达谱进行了差异分析。实验结果表明,碳酸酐酶Ⅰ和Ⅱ、肉碱棕榈酰转移酶Ⅱ、电压依赖阴离子通道2、二氢硫辛酰胺脱氢酶、3-磷酸甘油酸脱氢酶、丝氨酸蛋白酶抑制剂3、类似CREM转录调控元件激活因子等蛋白质与镉毒性相关,其中与能量代谢有关的蛋白质被镉诱导后显示表达下调。维生素C对镉毒性有明显的缓解作用。     

镉诱导金属硫蛋白在华溪蟹组织中的表达

采用体外暴露染毒法,研究了不同浓度与时间条件下,镉诱导河南华溪蟹(Sinopotamon henanense)金属硫蛋白(metallothionein,MT)在肝胰腺、肌肉、鳃和卵巢中的表达差异。镉浓度分别为0、14·5mg/L、29mg/L和58mg/L;处理时间依次为1d、3d和5d。利用镉血红蛋白饱和法和火焰原子吸收分光光度法(AAS)测定MT的蛋白含量。结果显示,用不同的染毒浓度和处理时间,镉在组织中诱导产生MT的含量有较大差异,其中肝胰腺MT的诱导量最大,变化规律也最明显;肌肉中也有较大量MT的表达;而鳃和卵巢MT的诱导量均较低。此外,本文分析了镉的浓度与时间梯度对诱导MT表达的影响与毒性效应机制。结论:组织不同,染毒浓度及时间不同,镉诱导MT的表达也不同,具有一定的组织差异性和规律性。     

力竭游泳诱导的大鼠睾丸金属结合蛋白的初步分离与鉴定

目的初步分离和鉴定力竭运动诱导的大鼠睾丸金属结合蛋白(testis metal-binding proteins,TMB-Ps)。方法 8只雄性SD大鼠一次性力竭游泳运动(8只对照)后6 h取睾丸和肝脏组织,用镉饱和法测定TMBPs和肝脏金属硫蛋白(metallothionein,MT)含量,用tricine-SDS-PAGE方法分离镉饱和法提取液的TMBPs组分和肝脏MT,用液相色谱-串联质谱法(LC-MS-MS)鉴定TMBPs分离条带。结果力竭运动组大鼠TMBPs水平(113.71±11.72)nmol Cd/g testis显著高于安静对照组(87.14±12.72)nmol Cd/g testis(P0.01),肝脏MT表达量(64.70±14.89)μg/g也显著高于安静对照组(7.32±3.31)μg/g(P0.001)。LC-MS-MS对tricine-SDS-PAGE分离的蛋白条带的鉴定结果为:TMBPs含有泛素、铜-锌-超氧化物歧化酶、酪蛋白样磷蛋白等蛋白质,另外还应包括MT。结论TMBPs由一组具有金属结合性、耐热性和诱导性的蛋白质所组成,主要有泛素、超氧化物歧化酶和酪蛋白样磷蛋白。镉饱和法并非测定金属硫蛋白的特异性方法。     

镉对黑斑蛙精巢组织结构的毒性效应

为了研究镉对两栖动物精巢组织结构的影响,用不同浓度Cd2 溶液对黑斑蛙(Rana nigromaculata)成体隔日皮下注射染毒,光镜下观察精巢组织的显微结构变化。结果表明,镉具有毒性效应,可以导致处理后的黑斑蛙精巢组织中的各级生精细胞、支持细胞和间质细胞受到损伤。对处理组和对照组的精巢组织分别用金属硫蛋白(MT)进行免疫组化定位观察,MT阳性颗粒在处理组和对照组均有表达,表达随处理组镉浓度的增大而减弱。     

PPARβ mRNA在全脑缺血/再灌注大鼠海马表达变化

目的探讨PPARβ mRNA在大鼠全脑缺血/再灌注损伤后的表达变化。方法采用双侧颈总动脉夹闭合并低血压的方法建立大鼠全脑缺血/再灌注模型。Morris水迷宫检测大鼠空间学习记忆能力,HE染色观察海马神经元形态变化,RT-PCR检测大鼠海马PPARβ mRNA的表达变化。结果全脑缺血/再灌注大鼠空间学习记忆能力明显下降,海马神经元核固缩;与假手术组相比,全脑缺血/再灌注后2h时PPARβ mRNA的表达明显增加,48h时达表达高峰,15d时表达下降但仍明显高于假手术组,而在30d时其表达略高于假手术组,但差异无统计学意义。结论全脑缺血/再灌注诱导大鼠海马PPARβ mRNA表达明显增加,此升高可能对全脑缺血/再灌注损伤具有保护作用。     

全脑缺血/再灌注大鼠海马PPARγ mRNA表达变化

目的 观察大鼠全脑缺血/再灌注损伤后海马PPARγ mRNA表达的动态变化.方法 采用夹闭双侧颈总动脉,颈总静脉抽血后回输建立大鼠全脑缺血/再灌注损伤模型.Morris水迷宫检测大鼠空间定向能力变化,HE染色观察海马病理组织学改变及RT-PCR法检测缺血再灌注后不同时间点PPARγ mRNA的表达变化.结果 全脑缺血/再灌注损伤导致大鼠空间学习及记忆能力明显下降,海马神经元出现明显的核固缩和细胞丢失.PPARγ mRNA的表达先升高后降低,以缺血/再灌注后48 h表达水平最高,30 d后接近正常水平.结论 全脑缺血/再灌注损伤大鼠海马组织中PPARγ mRNA的表达,在再灌注30 d内明显增加,表达高峰在48 h.     

大鼠脑缺血再灌注后Cathepsin D和caspase-9表达的动态变化

目的:探讨大鼠缺血再灌注后溶酶体组织蛋白酶D(Cathepsin D CD)、caspase-9在不同时段蛋白质及mRNA表达变化。方法:将60只S D大鼠随机分为三组:正常组(10只),假手术组(10只),脑缺血再灌注组(40只),线栓法制备大脑中动脉梗死模型(MCAO),免疫组化及RT-PCR法分别检测Cathepsin D、caspase-9的蛋白和mRNA表达。结果:与正常组和假手术组比较,模型组大鼠脑缺血再灌注损伤后6h Cathepsin D的蛋白和mRNA表达明显增强(P<0.05),24h达高峰,48h仍保存高水平。caspase-9蛋白和mRNA6h开始明显升高,12h达高峰,此后缓慢下降,但48h组仍显著高于对照组(P<0.05),结论:Cathepsin D、caspase-9在大鼠脑缺血再灌注后表达增强,溶酶体可能参与了脑缺血再灌注损伤后神经细胞凋亡的过程。     

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.