应激QTL座位22个微卫星标记与猪应激性状指标的 关系

摘要: 以皮特兰猪和二花脸猪为亲本建立的F2资源群体的52头猪进行2 h运输应激实验, 将仔猪出生后第3、10和17 d的“Backtest”评分(BS3、BS10、BS17)以及运输后各个体的血浆应激和代谢相关激素水平Insulin、ACTH、Cortisol、T3和T4作为运输应激性状指标。利用22个微卫星标记, 对这些应激指标进行相关性分析。结果表明: 各位点等位基因数为3~8个, 杂合度为0.4155~0.7432, 多态信息含量为0.3651~0.8150。方差分析显示: SW1808(P<0.01)和SW0320(P<0.05)对ACTH有显著影响; SW1303对Insulin、SW1092对Cortisol、SW0320对T3、S0101对T4以及SW2446对BS3影响达到显著水平(P<0.05); SW2446(P<0.01)、SW1816(P<0.05)和SW0092(P<0.05)对BS10有显著影响; SW2108、SW1816和SW1023对BS17有显著影响(P<0.05)。结果表明这11个微卫星标记对实验中的应激性状指标存在显著影响。     

西门塔尔牛产奶性状的微卫星标记分析

通过对西门塔尔牛育种核心群6个父系组成的150头母牛产奶性状的测定,结合微卫星标记技术,于4条染色体上选择12个微卫星位点进行产奶性状的微卫星标记分析,研究各位点对乳脂、乳蛋白、乳糖、干物质和奶中体细胞数的遗传效应。结果表明： 12个位点都具有高度多态性,杂合度（H）在0.64～0.86之间,多态信息含量（PIC）也达到0.60以上,最高者ILST093的多态信息含量为0.85;位点ILST093对奶中体细胞数有显著性影响(P<0.05),位点BMS711对乳脂率有显著性影响(P<0.05),位点BM1905与奶中乳糖含量呈显著相关(P<0.05),位点BM6438与五个产奶性状均无相关性。     

绵羊18号染色体微卫星多态性与后臀发育关系的研究

根据绵羊18号染色体遗传连锁图谱及相关报道, 选择了可能与Callipyge基因连锁和有关的10个高度多态微卫星基因座(ILSTS54、TGLA337、 HH47、TGLA122、BP33、OB2、BM3413、MCM38、MCMA26和CSSM18), 分别对Dorset和Suffolk两个肉羊群体的遗传特性进行了分析。研究发现, 同一微卫星基因座在Suffolk与Dorset群体间的群体遗传参数以及对同一性状的影响情况明显不同。Dorset群体中, 等位基因个数为8~16个, 杂合度为0.8370~0.9252, 多态信息含量为0.8221~0.9167; 而在Suffolk群体中相应参数分别为5~10, 0.7603~0.8913与0.7176~0.8809。对10个微卫星基因座进行臀宽的最小二乘分析, 结果表明: 在Dorset群体中, 微卫星基因座BM3413、MCMA26和CSSM18对臀宽有显著影响(P<0.05), 其余7个微卫星对后臀宽度的影响均未达到显著水平(P>0.05); Suffolk群体中微卫星基因座TGLA122、BM3413、MCM38和CSSM18对绵羊臀宽存在显著或极显著影响(P<0.05或0.01), 其余6个微卫星基因座对臀宽的影响均未达到显著水平(P>0.05)。研究表明, 导致新疆肉羊群体后臀肌过度发育可能是其他基因或QTL的作用。     

白颈长尾雉微卫星多态性的遗传学分析

采用7个微卫星位点遗传标记,对白颈长尾雉(Syrnaticus ellioti)4个地理种群105个个体进行了种群遗传分析。研究发现4个地理种群均偏离Hardy-Weinberg平衡,共检测到62个等位基因,平均等位基因数目为8.86;大多数微卫星位点的观察杂合度值较低,平均为0.504,要明显低于期望杂合度。7个位点的多态信息含量为0.549～0.860,平均为0.712。用无限等位基因模型、逐步突变模型和双相突变模型对4个地理种群的种群瓶颈效应检测,发现各种群近期内都经历过瓶颈效应的影响。地理种群之间的Fst值表明,贵州与湖南地理种群间的分化达到了极显著水平(P<0.001);由Nei氏的无偏遗传距离所构建的邻接树显示,贵州地理种群与湖南地理种群的遗传关系较远。微卫星对不同地理种群的分层分子变异分析(贵州地理种群对其他地理种群)发现:来自地理种群间和组群间的遗传变异量相对较小;而同一地理种群内个体之间的变异量较大(92.84%),且达到显著水平。     

西门塔尔牛产奶性状的微卫星标记遗传效应分析

在4条染色体上选择12个微卫星标记对西门塔尔牛育种核心群6个父系组成的150头母牛产奶性状(包括乳脂、乳蛋白、乳糖、干物质含量和奶中体细胞数)进行分子标记遗传效应分析.结果表明:12个微卫星位点都具有高度多态性,杂合度(H)均在0.64～0.86之间,多态信息含量(PIC)达0.60以上,最高为0.85(ILST093);位点ILST093对奶中体细胞数有显著性影响(P＜0.05);BMS711对乳脂率有显著性影响(P＜0.05);BM1905与奶中乳糖含量呈显著相关(P＜0.05);BM6438与5个产奶性状均无相关性.     

大口黑鲈生长性状的微卫星DNA标记筛选

本研究在人工养殖的大口黑鲈（Micropterus salmoides L.）群体中对40个微卫星位点进行扩增, 运用卡方检验分析微卫星位点在极端大个体组和极端小个体组中的基因型分布差异, 选择差异显著的16个微卫星位点对大口黑鲈随机群体进行基因型与性状的关联分析, 同时分析群体的遗传多样性。结果表明: 关联分析得到7个微卫星位点(JZL60、JZL67、JZL72、JZL124、MiSaTPW76、MiSaTPW117和MiSaTPW173)与体重、体长和体高显著或极显著相关(P<0.05或P<0.01), 同时对差异显著的位点进行不同基因型间与生长性状的多重比较, 找到了与体重、体长和体高性状相关的最有利基因型为JZL60位点的AA、JZL67位点的BB、JZL72位点的AC、MiSaTPW76位点的BB和MiSaTPW117位点的BC。应用这16个微卫星位点对随机群体进行遗传多样性分析, 共检测到47个等位基因,平均等位基因2.938个,每个位点检测到的等位基因数为2~5个、群体的平均观测杂合度、平均期望杂合度和平均多态信息含量分别为0.515、0.500和0.445, 表明该群体遗传多样性处于中等水平。     

尼罗罗非鱼ghrelin基因的多态性及其与生长性状相关SNP位点的筛选

为了研究尼罗罗非鱼(Oreochromis niloticus)生长激素促分泌素基因(ghrelin)的多态性及其与生长的相关性, 研究以两个尼罗罗非鱼群体(快长群体和基础群体)的DNA样本各40份为模板, 通过PCR扩增和测序获得ghrelin基因序列。通过Dnasp v5和MEGA 5.0分析序列多态性、筛选有效SNP 位点; 采用Snapshot法对两个群体子代ghrelin基因中SNP位点进行基因分型, 然后分析SNP位点基因型与生长性状的相关性。结果表明, 快长群体ghrelin基因中的单核苷酸变异位点数(S)比基础群体要少, 而核苷酸多态性(Pi)和平均核苷酸差异数(K)要略高于基础群体。共筛得3个有效SNP 位点(S1、S2和S3), 均分布于第1个内含子中。遗传结构分析表明, 3个SNP 位点在两个群体的子代中均为低度多态性位点(PIC0.25), 但处于Hardy-Weinberg平衡(P0.05);快长群体子代中3个SNP 位点的观测杂合度、期望杂合度和多态信息含量等遗传多样性参数均小于基础群体子代的相应值, 3个SNP 位点的遗传多样性参数、基因型和基因频率在同一群体中高度一致, SNP 位点之间完全连锁。两个群体子代中3个SNP 位点处的优势基因型相同, 但快长群体子代中优势基因型频率要明显大于基础群体子代中相应基因型频率。对两个群体子代的生长性状与SNP基因型进行关联性分析的结果表明,尼罗罗非鱼个体的多项生长指标(体重、体长、体高、头长和尾柄高等)在不同基因型中存在显著差异(S1:GG AG, S2:TT AT, S3:AA AT)(P0.05)。D1双倍型(S1:GG, S2:TT, S3:AA)所对应的尼罗罗非鱼个体的多项生长指标(体重、体长、体高、头长和尾柄高等)显著高于D2双倍型(S1:AG, S2:AT, S3:AT)。以上结果表明, 尼罗罗非鱼ghrelin基因3个SNP 位点完全连锁, D1双倍型与快长性状密切相关, 可作为尼罗罗非鱼分子标记辅助育种的候选标记。     

利用传递不平衡分析在多群体中鉴别猪脐疝易感基因

在本实验室前期利用白色杜洛克×二花脸F₂资源家系开展脐疝易感位点全基因组扫描定位的基础上,文章在7号染色体上的SWR1928和10号染色体上的SW830易感标记区域,结合脐疝发病机制在多群体中进行脐疝位置功能候选基因的筛选和易感位点的精细定位。在两个显著关联的微卫星位点区域搜寻到12个位置功能候选基因,采用比较测序法,选取12个候选基因内共计40个SNP位点在白色杜洛克×二花脸资源家系F₂/F₃脐疝群体中进行基因分型,利用Plink v1.07软件对基因型数据进行质量控制和传递不平衡(Transmission disequilibrium test,TDT)分析。结果表明,IL16(Interleukin 16)基因中的g.708C>T位点和CDC73(Cell division cycle 73)基因中的g.10664G>A位点与脐疝的关联性达到显著水平(P<0.05)。对这两个位点在西方商业猪种脐疝患病家系中进行基因分型和TDT验证分析,发现CDC73基因中的g.10664G>A位点仍与猪脐疝呈显著关联(P<0.05)。同时对CDC73基因中与资源家系脐疝呈弱相关的两个SNP位点g.10546A>G和g.10811A>G在西方商业猪种中进行TDT验证分析,发现这两个SNP位点与商业猪种脐疝发生的关联性达到极显著水平(P<0.01)。根据文章的分析结果,结合脐疝发生的生理机制及CDC73基因的生物学功能,推测CDC73基因可能为猪脐疝发生的易感基因。     

不同猪种肠毒素大肠杆菌（ETEC）F4受体的微卫星标记遗传效应分析

从猪13号染色体选取与E.coli F4受体基因连锁的4个微卫星座位研究中外猪种间的遗传差异性,并分析不同基因型与F4受体黏附表型的关系。结果表明,4个猪种在4个基因座均具有高度多态性,杂合度（H）在0.6117～0.7500之间,多态信息含量（PIC）达0.5749以上;同时中外猪种基因频率存在差异,微卫星座位连锁越紧密,差异性越大。微卫星S0222不同基因型间在沙子岭猪F4ab血清型黏附表型中差异显著;SW458座位AC基因型在沙子岭、大白两个品种中无黏附表型,可望作为对E.coliF4抗性基因的遗传标记。     

绵羊3号染色体的遗传连锁图谱构建及QTL定位

以四川凉山半细毛羊资源群体为研究对象, 选取位于绵羊3号染色体上的9个微卫星标记, 构建遗传连锁图谱, 用QTLExpress软件对影响绵羊生长发育的5个性状进行QTL定位分析。结果显示: (1) 9个微卫星标记的平均多态信息含量和平均群体杂合度分别为0.606 (0.378～0.738)、0.650 (0.404～0.766); (2) 连锁图谱总长为339.8 cM, 标记平均间距为42.5 cM, 略长于国际主要绵羊作图组织构建的图谱; (3) QTLExpress分析表明, 检测到影响羔羊断奶重、断奶日增重和成年体重的3个QTL, 分别位于99 cM、219 cM、273 cM处, 影响断奶日增重和成年体重的QTL都达到显著水平, 而影响羔羊断奶重的QTL未达到显著水平。     

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.