在基于BAC的EB病毒基因组中引入突变

为了在Epstein-Barr病毒(EBV)172kb的基因组中引入突变以研究基因功能,建立了一种简单有效的基因操作方法.在载体pcDNA3.1( )上操作,将两端含有重组蛋白FLP识别位点(FRT)的卡那霉素筛选标记基因(kan)与鼻咽癌(NPC)来源的、包含LMP1基因全长ORF的gDNA"无缝"连接(无外源序列插入).连接后的kan-LMP1线性DNA片段经转化、由λ噬菌体中redαβγ系统介导在E.coli中发生同源重组(ET克隆),用kan-LMP1替代了BAC-EBV(p2089)中相应的LMP1基因区域,然后经过重组蛋白FLP对FRT-kan-FRT特异性的识别,切除了引入的kan基因,留下一个69bp的FRT"疤痕".通过抗性筛选和对菌液进行PCR扩增可以鉴定突变子.这种经改进并程序化的方法.也适应于引入其它突变或在其它BAC-疱疹病毒基因组中引入突变.     

沙眼衣原体感染后妊娠大鼠子宫组织C3 和Crry mRNA的表达变化

目的通过大鼠生殖道沙眼衣原体(Chlamydia trachomatis,CT)感染模型研究CT初次感染后妊娠大鼠在胚胎着床期子宫局部补体C3和补体调节蛋白Crry的mRNA表达量的变化。方法选择成年雌性SD大鼠36只,随机均分为正常组和感染组,感染组通过阴道接种CT D型株。而后在妊娠大鼠的胚胎植入期(即妊娠第5、6、7d)分别处死大鼠,取子宫组织计数胚胎植入数,通过逆转录扩增(RT-PCR)方法半定量检测在胚胎植入期C3和Crry的mRNA的表达量的变化,并通过SPSS软件对数据差异显著性进行分析。结果1.感染组在植入期C3的mRNA比正常组高表达,差异有显著性(P<0.001);2.Crry的mRNA虽比正常组表达有所增加,但两组数据无显著性差异(P>0.05);3.感染组较正常组平均胚胎植入数下降(P<0.01),并且感染组C3mRNA的表达量与对应的胚胎植入数存在显著的负相关(r=(0.638,P<0.05)。结论大鼠生殖道感染CT后,妊娠大鼠胚胎植入数降低,而这种变化很可能与子宫局部补体C3的高表达及过量的补体活化有关。     

动情周期中大鼠子宫和输卵管壁肥大细胞数量变化的研究

用放射免疫分析法对动情周期中大鼠血清雌二醇浓度进行检测;取子宫、输卵管常规石蜡切片、H－E染色,并用甲苯胺蓝染色显示肥大细胞,于光镜低倍视野下计数。结果显示：动物血清雌二醇浓度依次为：动情期（E）组＞动情前期（PE）组＞动情后期（ME）组＞动情间(DE)且,各组间差异均有显性;在子宫,肥大细胞分布于宫壁肌怪平滑肌束间的结缔组织内、近小血管处,以微血管周居多,常见单个散在,于ME子宫内膜尚偶见肥大细胞;输卵管肥大细胞局限于其外膜层内、近小血管周围,亦多散在。子宫、输卵管壁内的肥大细胞镜下呈圆形、椭圆形或略不规则形,胞浆内充满紫红色粗大颗粒,子宫肥大细胞数量依次为：ME＞DE＞PE＞E,各组间差异有生（DE与PE、PE与E,P＜0.05,余组间P＜0.01）;输卵管壁内肥大细胞数量各组间差异无显性（P＞0.05）。本尚对大鼠血清雌二醇水平波动与子宫、输卵管壁内肥大细胞数量变化的关系及其生理意义进行了讨论。     

LRRC4 inhibits glioblastoma cell proliferation, migration, and angiogenesis by downregulating pleiotropic cytokine expression and responses

Leucine-rich repeat C4 (LRRC4) has been shown to inhibit glioma cell proliferation, however, little is known about the mechanism(s) underlying the action of LRRC4. Here, we show that two glioblstoma U251 cell clones stably expressing LRRC4 were established. LRRC4 expression significantly inhibited the expression of some cytokines and their receptors determined by microarray and Western blot assays, and dramatically reduced cytokine-induced AP-1, NF-kB, and CyclinD1 activation in glioma cells. Furthermore, LRRC4 expression in glioma cells significantly downregulated spontaneous and cytokine-induced expression of K-RAS and phosphorylation of c-Raf, ERK, AKT, NF-kBp65, p70S6K, and PKC, suggesting that LRRC4 inhibited receptor tyrosine kinase (RTK) signaling pathways. Moreover, treatment with bFGF, IGF1, or IGF2 stimulated LRRC4(-/-), but not the LRRC4(+), glioma cell proliferation, indicating that LRRC4 mitigated cytokine-stimulated proliferation in glioma cells. In addition, treatment of LRRC4(-/-) glioma cells with EGF, IGF2, or PDGF promoted long distance mobilization, but induced little migration in LRRC4(+) glioma cells, suggesting that LRRC4 retarded cytokine-promoted glioma cell migration in vitro. Finally, human vessel endothelial cells (ECV304) treated with VEGF grew, aligned and formed hollow tube-like structures in vitro. In contrast, LRRC4(+) ECV304 treated with VEGF failed to form vessel-tube structures. Collectively, LRRC4 expression inhibited the expression of some growth factors, cytokines and their receptors, and the capacity of glioma cells responding to cytokine stimulation, leading to inhibition of glioma cell proliferation. Conceivably, induction of LRRC4 expression may provide new intervention for human glioma in the clinic.     

Nonfunctional alleles of long‐day suppressor genes independently regulate flowering time

Due to the remarkable adaptability to various environments, rice varieties with diverse flowering times have been domesticated or improved from Oryza rufipogon. Detailed knowledge of the genetic factors controlling flowering time will facilitate understanding the adaptation mechanism in cultivated rice and enable breeders to design appropriate genotypes for distinct preferences. In this study, four genes (Hd1, DTH8, Ghd7 and OsPRR37) in a rice long‐day suppression pathway were collected and sequenced in 154, 74, 69 and 62 varieties of cultivated rice (Oryza sativa) respectively. Under long‐day conditions, varieties with nonfunctional alleles flowered significantly earlier than those with functional alleles. However, the four genes have different genetic effects in the regulation of flowering time: Hd1 and OsPRR37 are major genes that generally regulate rice flowering time for all varieties, while DTH8 and Ghd7 only regulate regional rice varieties. Geographic analysis and network studies suggested that the nonfunctional alleles of these suppression loci with regional adaptability were derived recently and independently. Alleles with regional adaptability should be taken into consideration for genetic improvement. The rich genetic variations in these four genes, which adapt rice to different environments, provide the flexibility needed for breeding rice varieties with diverse flowering times.     

CT感染大鼠子宫内膜植入窗期基质金属蛋白酶的表达

目的 通过大鼠生殖道沙眼衣原体（chlamydia trachomatis,CT）感染模型研究CT初次感染后妊娠大鼠在子宫内膜植入窗期基质金属蛋白酶-9（MMP-9）及金属蛋白酶组织抑制物-1（TIMP-1）的表达对胚胎着床的影响。方法选择成年雌性SD大鼠30只,随机均分为对照组和感染组,感染组通过阴道接种CTD型株,而后在妊娠大鼠的植入窗期（即妊娠第5、6、7天）分别处死大鼠,采用链菌生物素蛋白一过氧化酶连接法和免疫组化测定两组子宫内膜种植窗期MMP-9及TIMP-1。采用HPIAS-1000高清晰度彩色病理图文小报告管理系统测定感染组和对照组中MMP-9＼T1MP-1在单位面积中各项免疫组织化学反应阳性颗粒的平均光密度值,并通过SPSS软件对数据差异显著性进行分析。结果在两组大鼠的子宫内膜中MMP-9均呈阳性表达。腺上皮细胞、腔上皮细胞和基质细胞胞浆内均可见棕黄色颗粒沉着,上皮细胞染色强度大于基质;感染组的表达较对照组弱,差异有显著性（P〈0．05）。TIMP-1表达特点和MMP-9相似,感染组的表达也较对照组弱,差异有显著性（P〈0．05）。结论生殖道感染CT后,妊娠大鼠子宫内膜植入窗期MMP-9及TIMP-1的低表达,可能是影响胚胎着床、导致不孕的重要因素。     

A multi-center study on Molecular Epidemiology of Human Respiratory Syncytial Virus from Children with Acute Lower Respiratory Tract Infections in the Mainland of China between 2015 and 2019

Virologica Sinica - Human respiratory syncytial virus (RSV) is a major pathogen of acute lower respiratory tract infection among young children. To investigate the prevalence and genetic...     

大鼠输卵管感染沙眼衣原体后IL-18mRNA的表达及介质效应

目的通过大鼠沙眼衣原体(chlamydial trachomatis,CT)感染模型来研究白介素-18(IL-18)在初次感染后不同阶段的表达及其与干扰素-γ(IFN-γ)之间的介质效应.方法选择成年雌性SD大鼠24只,通过手术从一侧卵巢囊接种沙眼衣原体D型株,分别于感染后3d、7d、14d将大鼠处死,取手术侧输卵管以RT-PCR检测感染前后不同时间输卵管局部IL-18 mRNA及IFN-γ mRNA的表达量;用酶联免疫吸附(ELISA)法测定输卵管组织IFN-γ蛋白含量.结果在接种24h后即可检测到IFN-γ mRNA和IL-18 mRNA的表达,并持续升高.在感染后的3 d至7 d内,两种细胞因子的mRNA表达量一直处于高水平状态,大约两周后它们的mRNA表达已明显下降.感染组织内IFN-γ水平与基因表达趋势基本一致.相关分析表明,输卵管组织IL-18 mRNA表达与IFN-γ mRNA、IFN-γ水平均呈显著正相关.结论输卵管组织IL-18 mRNA表达在初次感染后早期即显著增多,并呈逐渐升高的趋势;感染后IL-18 mRNA基因表达对IFN-γ的生成具有重要影响.     

补体系统与细胞因子的相互作用

补体和细胞因子均为免疫系统中的重要组成部分,共同参与了机体抵抗病原体的防御反应、免疫调节以及机体的免疫病理性损伤反应。Glq、C3及其活性片段,c5及其活性片段以及其它的外体成分与TNF-α,IFN-γ、IL-1、IL-6等炎性细胞因子在炎症过程中通过各种直接或间接的途径相互作用,二者之间的平衡最终决定了炎症的发展与转归。文章不仅总结了新近研究所表明的补体对CK的调节作用,而且介绍了近年来关于细胞因子调节补体研究的新发展。     

LRRC4 inhibits human glioblastoma cells proliferation, invasion, and proMMP-2 activation by reducing SDF-1 alpha/CXCR4-mediated ERK1/2 and Akt signaling pathways

Gliomas take a number of different genetic routes in the progression to glioblastoma multiforme, a highly invasive variant that is mostly unresponsive to current therapies. The alpha-chemokine stromal cell-derived factor (SDF)-1 alpha binds to the seven transmembrane G-protein-coupled CXCR-4 receptor and acts to modulate cell migration and proliferation by activating multiple signal transduction pathways. Leucine-rich repeats containing 4 (LRRC4), a putative glioma suppressive gene, inhibits glioblastoma cells tumorigenesis in vivo and cell proliferation and invasion in vitro. We also previously demonstrated that LRRC4 controlled glioblastoma cells proliferation by ERK/AKT/NF-kappa B signaling pathway. In the present study, we demonstrate that CXC chemokine receptor 4 (CXCR4) is expressed in human glioblastoma U251 cell line, and that SDF-1 alpha increases the proliferation, chemotaxis, and invasion in CXCR4+ glioblastoma U251 cells through the activation of ERK1/2 and Akt. The reintroduction of LRRC4 in U251 cells inhibits the expression of CXCR4 and SDF-1 alpha/CXCR4 axis-mediated downstream intracellular pathways such as ERK1/2 and Akt leading to proliferate, chemotactic and invasive effects. Furthermore, we provide evidence for proMMP-2 activation involvement in the SDF-1 alpha/CXCR4 axis-mediated signaling pathway. LRRC4 significantly inhibits proMMP-2 activation by SDF-1 alpha/CXCR4 axis-mediated ERK1/2 and Akt signaling pathway. Collectively, these results suggest a possible important "cross-talk" between LRRC4 and SDF-1 alpha/CXCR4 axis-mediated intracellular pathways that can link signals of cell proliferation, chemotaxis and invasion in glioblastoma, and may represent a new target for development of new therapeutic strategies in glioma.