利用微卫星技术分析不同类群鸡的遗传多样性

利用8个微卫星标记分析了6个生产类群鸡的遗传多样性。计算了各群体在各位点上的等位基因频率,并据此计算出各群体的平均遗传杂合度(h)、多态信息含量(PIC)和有效等位基因数(Ne)。结果表明:6个鸡群在8个微卫星座位上的基因频率存在明显的差异,其平均基因杂合度为0.7317,平均多态信息含量为0.6815。其中,群体平均杂合度最高的是安卡红鸡,为0.7716;平均杂合度最低的是新罗曼鸡,为0.7073。所选的8个微卫星座位均为高度多态,可作为有效的遗传标记用于鸡群体遗传多样性的分析。     

IGF1调控区微卫星座位对金华猪生长性能的影响

类胰岛素生长因子IGF1及其相关结合蛋白和跨膜受体IGFR在哺乳动物的生长过程中扮演着重要角色。本文基于最小二乘法分析了IGF1 5′ 调控序列微卫星座位对金华猪初生重, 断奶重, 120日龄重, 180日龄重和出生窝重等生长性状的影响。结果表明: 286/286基因型对金华猪初生重有显著影响(P<0.05); 280/286基因型对金华猪开产后出生窝重影响显著(P<0.05), 进一步通过等位基因平均替代效应分析发现274 bp和286 bp等位基因有利于提高初生重, 280 bp等位基因有利于第二胎出生窝重的提高。同时通过相关性分析发现金华猪开产母猪出生窝重、总产仔数和产活仔数间的相关性极显著(P<0.01), 因此出生窝重的增加有利于提高金华猪的产仔性能。     

猪F2设计资源家系中4条染色体微卫星标记分析

利用中国地方猪种蓝塘猪(16头母猪)与外来品种长白猪(8头公猪)按F2设计建立资源家系, 根据美国肉畜中心(USDA-MARC 2.0)公布的猪连锁图谱, 在1、4、7和8号染色体上间隔10~20 cM选择一个微卫星标记, 共31个标记, 采用WAVEÒ核苷酸片段分析系统和ABI 377 DNA序列分析仪检测资源群体的P、F1和F2代个体微卫星的基因型, 对其基因频率、杂合度和多态信息含量等进行统计分析。结果发现: 利用ABI 377检测的猪1、4和8号染色体上的有效微卫星标记21个, 其中13个标记的18个等位基因片段大小超过了网上已报道的结果, 发现新等位基因的标记占62%; 在31个微卫星标记中, 杂合度(h)在0.043~0.7855之间, 总平均杂合度为0.6460, 其中70%座位的h>0.60; 总平均多态信息含量(PIC)为0.5949, 有77.4%位点的PIC>0.5。统计分析结果表明, 选用的微卫星标记能够较好地提供标记信息, 为进一步在该家系中进行猪重要性状的QTL定位打下了良好的基础。     

鲮鱼的微卫星位点筛选和群体遗传多样性初步分析

利用鲤科鱼类微卫星引物在鲮鱼中进行扩增,结果在24对引物中,13对引物能成功扩增,且在鲮鱼中的扩增产物表现稳定,其中11对有较高多态性,等位基因数在2—7个之间,扩增的条带符合孟德尔遗传规律。随后利用筛选的微卫星座位对鲮鱼野生和养殖群体遗传多样性进行了初步分析。分析结果显示鲮鱼野生群体的平均等位基因数5.2个;观测杂合度在0.25与0.8之间,平均观测杂合度(Ho)是0.61±0.2 ,平均期望杂合度(He)是0.8±0.09 ;群体座位平均多态信息含量(PIC)为0.72±0.1。相比之下,养殖群体的平均观测杂合度(Ho)和平均期望杂合度(He)都低于野生群体,分别是0.59±0.2、0.75±0.1。两群体间的遗传相似度为0.7774、遗传距离为0.2518。研究表明用其他鱼类分离出的微卫星引物可以快速筛选到适用于鲮鱼遗传分析的微卫星座位。     

镜鲤繁殖群体的遗传结构及微卫星标记与经济性状的相关性分析

选用35个多态性微卫星分子标记对天津换新良种场镜鲤一个繁殖群体的有效等位基因数(Ae)、观测杂合度(Ho)、期望杂合度(He)、多态信息含量(PIC) 等进行了检测, 以卡方检验估计群体Hardy-Weinberg平衡。结果表明：在35个基因座共检测到118个等位基因, 平均等位基因数为3.37个, 每个座位检测到的等位基因数2~7个不等, 平均有效等位基因数为2.16, 观测杂合度平均值0.431, 无偏期望杂合度的平均值为0.4736, 平均多态信息含量0.42, 说明这个群体属于中度多态, 遗传多样性水平不高。卡方检验的P值显示多于半数的位点都发生了偏离。并将35个基因座的不同基因型与个体的体重、体长值进行了连锁分析, 得到了4个与体重、体长连锁的基因型, 并将所得结果与鲤鱼体长性状QTL定位结果进行对比, 其中HLJ319标记与QTL定位结果基本一致。分析了几个严重偏离平衡的基因型, 并讨论出现这种现象的可能原因。     

黄羽肉鸡微卫星多态性与体重的相关分析

利用选自家禽基因组中的13个微卫星标记,对黄羽肉鸡A系、B系回交F2代群体100个个体的基因组DNA进行PCR扩增,经分析后,计算出各标记的基因频率、多态信息含量、杂合度,通过与性状初生重、8周龄体重的相关分析,得出与体重相关的标记,并进行了同一标记不同基因型间的多重比较。     

贵州小型香猪和广西巴马小型猪微卫星位点的遗传学分析

利用35个微卫星位点对贵州小型香猪,广西巴马小型猪的封闭群进行了遗传检测,计算出两个小型猪品系个体样本微卫星位点的平均杂合度,多态信息含量（PIC）、有效等效基因数及品系间的遗传距离。结果表明两个品系的小型猪平均杂合度和PIC均较低,有效等效基因数与实测等位基因数较接近,也表明两品系均有稳定的遗传;两者的遗传距离表明贵州小型香猪和广西巴马小型猪亲缘关系较近,同时表明两者已分别成为两个猛增的封闭群动物。     

鲮鱼的微卫星位点筛选和群体遗传多样性初步分析

利用鲤科鱼类微卫星引物在鲮鱼中进行扩增,结果在24对引物中，13对引物能成功扩增，且在鲮鱼中的扩增产物表现稳定，其中11对有较高多态性,等位基因数在2—7个之间，扩增的条带符合孟德尔遗传规律。随后利用筛选的微卫星座位对鲮鱼野生和养殖群体遗传多样性进行了初步分析。分析结果显示：鲮鱼野生群体的平均等位基因数5.2个；观测杂合度在0.25与0.8之间，平均观测杂合度(Ho)是0.61±0.2，平均期望杂合度(He)是0.8±0.09；群体座位平均多态信息含量(PIC)为0.72±0.1。相比之下，养殖群体的平均观测杂合度(Ho)和平均期望杂合度(He)都低于野生群体，分别是0.59±0.2、0.75±0.1。两群体间的遗传相似度为0.7774、遗传距离为0.2518。研究表明：用其他鱼类分离出的微卫星引物可以快速筛选到适用于鲮鱼遗传分析的微卫星座位。     

山东部分地方猪种MyoG基因5''''端遗传多态性及遗传效应分析

采用PCR-SSCP方法对莱芜猪、大蒲莲猪、沂蒙黑猪和里岔黑猪的肌细胞生成素(myogenin,MyoG)基因5'端进行单核苷酸多态性检测,并分析MyoG基因对猪的初生重、60日龄重、210日龄重,60～210日龄平均日增重和背膘厚的影响。根据猪MyoG基因5'端的DNA序列(U14331)设计3对引物,发现5-2引物对扩增的片段有多态性,且存在3种基因型(AA、AB、BB),并对纯合子进行测序,发现2080位G→A突变。χ2独立性检验表明,基因型频率在莱芜猪和大蒲莲猪与沂蒙黑猪和里岔黑猪间存在显著差异(P<0.05)。固定效应模型分析结果表明,初生重基因型间差异显著(P<0.05),而60日龄重、210日龄重、60～210日龄平均日增重和背膘厚基因型间差异不显著(P>0.05)。最小二乘分析结果表明,BB基因型与其他两种基因型比较有较小的初生重和日增重,同AA和AB基因型比较差异极显著(P<0.01),3种基因型在初生重和60～210日龄日增重的大小排列顺序一致,为AA>AB>BB。因此,推测基因型对个体的初生重和日增重存在一定的影响,选择带有A等位基因的个体有望提高个体的初生重和日增重。     

布氏罗非鱼微卫星位点筛选和群体遗传多样性分析

为阐明布氏罗非(Tilapia buttikoferi)群体遗传变异和遗传结构状况,采用50个尼罗罗非鱼特异性的微卫星分子标记对45个布氏罗非鱼个体进行遗传检测.结果有27对引物能获得稳定的特异性条带,占总数的54%,其中16个多态性微卫星座位共检测出52个等位基因.每个座位的等位基因数为2～6之间,平均每个座位为3.24;平均观测杂合度(Ho)为0.5266,平均期望杂合度(He)为0.5237,平均多态信息含量为0.4652,表明布氏罗非鱼群体遗传多样性较丰富,种群结构处于合理状态.     

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.