ITE and TCDD Differentially Regulate the Vascular Remodeling of Rat Placenta via the Activation of AhR

Vascular remodeling in the placenta is essential for normal fetal development. The previous studies have demonstrated that in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, an environmental toxicant) induces the intrauterine fetal death in many species via the activation of aryl hydrocarbon receptor (AhR). In the current study, we compared the effects of 2-(1′H-indole-3′-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) and TCDD on the vascular remodeling of rat placentas. Pregnant rats on gestational day (GD) 15 were randomly assigned into 5 groups, and were exposed to a single dose of 1.6 and 8.0 mg/kg body weight (bw) ITE, 1.6 and 8.0 µg/kg bw TCDD, or an equivalent volume of the vehicle, respectively. The dams were sacrificed on GD20 and the placental tissues were gathered. The intrauterine fetal death was observed only in 8.0 µg/kg bw TCDD-exposed group and no significant difference was seen in either the placental weight or the fetal weight among all these groups. The immunohistochemical and histological analyses revealed that as compared with the vehicle-control, TCDD, but not ITE, suppressed the placental vascular remodeling, including reduced the ratio of the placental labyrinth zone to the basal zone thickness (at least 0.71 fold of control), inhibited the maternal sinusoids dilation and thickened the trophoblastic septa. However, no marked difference was observed in the density of fetal capillaries in the labyrinth zone among these groups, although significant differences were detected in the expression of angiogenic growth factors between ITE and TCDD-exposed groups, especially Angiopoietin-2 (Ang-2), Endoglin, Interferon-γ (IFN-γ) and placenta growth factor (PIGF). These results suggest ITE and TCDD differentially regulate the vascular remodeling of rat placentas, as well as the expression of angiogenic factors and their receptors, which in turn may alter the blood flow in the late gestation and partially resulted in intrauterine fetal death.     

Formation of Adeno-Associated Virus Circular Genomes Is Differentially Regulated by Adenovirus E4 ORF6 and E2a Gene Expression

A central feature of the adeno-associated virus (AAV) latent life cycle is persistence in the form of both integrated and episomal genomes. However, the molecular processes associated with episomal long-term persistence of AAV genomes are only poorly understood. To investigate these mechanisms, we have utilized a recombinant AAV (rAAV) shuttle vector to identify circular AAV intermediates from transduced HeLa cells and primary fibroblasts. The unique structural features exhibited by these transduction intermediates included circularized monomer and dimer virus genomes in a head-to-tail array, with associated specific base pair alterations in the 5′ viral D sequence. In HeLa cells, the abundance and stability of AAV circular intermediates were augmented by adenovirus expressing the E2a gene product. In the absence of E2a, adenovirus expressing the E4 open reading frame 6 gene product decreased the abundance of AAV circular intermediates, favoring instead the linear replication form monomer (Rf_m) and dimer (Rf_d) structures. In summary, the formation of AAV circular intermediates appears to represent a new pathway for AAV genome conversion, which is consistent with the head-to-tail concatemerization associated with latent-phase persistence of rAAV. A better understanding of this pathway may increase the utility of rAAV vectors for gene therapy.     

Dynamic distribution of epidermal growth factor during mouse embryo peri-implantation

Embryo implantation depends on the synchronized development of the blastocyst and the endometrium. This process is highly controlled by the coordinated action of the steroid hormones: estrogen and progesterone. By autocrine, paracrine or juxtacrine routes, some growth factors or cytokines are involved in this steroidal regulation pathway. Here we report the effects of epidermal growth factor (EGF) on embryo implantation in the mouse, the expression and distribution patterns of EGF protein in the mouse blastocyst, ectoplacental cone (EPC) and peri-implantation uterus on days 1-8 of gestation.By RT-PCR and dot blot, we found that EGF and its receptor (EGFR) are co-expressed in the blastocyst and peri-implantational uteri of pregnant days 2-8 (D2-D8) mice. Injection of EGF antibody into a uterine horn on the third day of pregnancy (D3) significantly reduced the number of mouse embryos that implanted on D8, indicating EGF have a function in the mouse embryo implantation.Further investigation by using indirect immunofluorescence and confocal microscope was made to trace EGF and EGFR protein localization during the mouse embryo implantation. EGF and EGFR are co-localized in the blastocyst, and in the secondary trophoblastic giant cells (SGC) of the EPC. At the pre-implantation stage, the distribution of EGF protein in the mouse uterus changes from epithelium to stroma. On D1 of pregnancy, EGF is mainly distributed in uterine stroma and myometrium. On D2, it is present in the uterine epithelium. On D3, it changes again from the uterine epithelium to the stroma. By D4, EGF is predominantly in the stroma. This dynamic distribution correlates with the proliferation activity of uterine cells at each period. On D6-D8 of embryo implantation, EGF 3 protein accumulates at the uterine mesometrial pole, a region that contributes to the trophoblastic invasiveness and placentation.This temporal and spatial localization of EGF protein in the mouse uterus implicates the cytokine in the regulation of trophoblastic invasiveness and uterine receptiveness.     

喀斯特槽谷区土地石漠化与综合治理技术研发

深入揭示流域尺度水-土-生资源格局和研发因地制宜的水-土-生治理技术是"十三五"石漠化治理工程的主要瓶颈。国家重点研发计划——"喀斯特槽谷区土地石漠化过程及综合治理技术研发与示范"项目(2016YFC0502300)针对槽谷区特点,锁定两个关键科学问题和五个关键技术,从过程机理研究-技术研发-应用示范3个层面解剖区域水/土/生物资源分布格局与地质地貌之间的关系,阐明石漠化过程中的相关生态变化机理,因地制宜地研发水土资源高效利用、土壤地上/下流/漏失阻控与生态恢复技术;研发野生砧木及经济树种互作效应与优化配套技术,构建槽谷区可持续的生态系统和生态产业模式并示范推广,为区域生态改善和贫困问题解决提供科技支撑。     

温度对超高浓度酒精生料发酵体系的影响

通过对超高底物浓度生料发酵中温度的影响研究发现,采用温度梯度的方法可大幅提高酵母的生产效率。以高粱为例,采用35%绝对干物浓度,在新型生料水解酶的配合下,通过合适的逐级降温培养方式,使用普通酒精干酵母,在90h内发酵醪液酒精浓度可达20%(V/V)以上。     

6-羟多巴胺纹状体内注射制作大鼠帕金森病模型的研究

目的 为拓宽6-OHDA损毁多巴胺能神经元所制备大鼠帕金森病模型的应用范围,采用多位点纹状体内注入6-OHDA的途径来制备模型。方法 研究用SD大鼠,两个针道内四点定位注射,每点注射3μg／μ16-OHDA3μl。结果 术后两周出现缓慢旋转,4周旋转行为达到7转／分并保持稳定;形态学染色可见损毁1周后注射侧黑质酪氨酸羟化酶免疫组化阳性细胞减少20％,2周后减少38％,3～4周减少70％以上,6周后损伤趋缓。高效液相-电化学法活体检测纹状体内多巴胺的代谢产物3、4-二羟基苯乙酸(DOPAC)和高香草酸(HVA),发现注射侧和非注射侧相比含量分别下降98．33％和96．05％;组织匀浆检测损毁侧黑质多巴胺含量下降了73％以上,3、4-二羟基苯乙酸(DOPAC)含量下降60％。结论 纹状体内注射6-OHDA能够制备帕金森病大鼠模型。     

鼠伤寒沙门氏菌嘌呤生物合成调控研究IX.PUR box的突变分析2

为研究１６ｂｐ ＰＵＲｂｏｘ 中８ 个完全保守的碱基中的２ 个碱基在与ｐｕｒＲ＋ 阻遏蛋白结合中的功能,对它们分别作了定点突变,使其分别从Ｃ,Ｇ 突变为Ｇ,Ａ。凝胶阻滞实验结果表明,含上述保守碱基突变的ＰＵＲｂｏｘ 均不能与ｐｕｒＲ＋ 阻遏蛋白结合。证明这２ 个保守碱基对维持ＰＵＲｂｏｘ 的功能是必须的,其中任一改变都导致ＰＵＲｂｏｘ 功能的丧失。     

子宫颈糜烂病毒病因的探讨

491份宫颈拭子病毒分离结果表明:糜烂宫颈单纯疱疹病毒(HSV)分离阳性率(30.8％)是正常宫颈(2.6％)的11.8倍,用人干扰素治疗一个疗程后,病毒分离率下降至疗前的1/4.36例糜烂宫颈活体组织DNA分子杂交表明,乳头瘤病毒16型(HPV-16)阳性者占52.8和,HPV-18占17.9％,HPV-6B占28.1％,HPV-11占7.7％,251例宫颈糜烂患者经人(?)D型基因工程干扰素双盲对比治疗后,总有效率达93.8％,显效率达60％,分析临床疗效与HSV分离率的变化表明,临床有效病例中有35％(49/140)在治疗后病毒阴转,有57％在疗前疗后均未分离出HSV,有5％在疗前疗后保持阳性不变,有2.9％疗前阴性,疗后阳性,上述结果表明,HSV和HPV与慢性宫颈炎有一定关系。     

Mussaenda yunnanensis sp. nov. (Rubiaceae), a new functionally dioecious species from Yunnan,China

Mussaenda yunnanensis, a new dioecious species of Rubiaceae from Yunnan Province, China, is described and illustrated. The new species can be recognized by its slender stem, congested‐cymose inflorescences and long corolla tubes. Differences between M. yunnanensis and two morphologically similar species (M. pubescens and M. antiloga) are presented. We also provide a key to all dioecious species of Mussaenda in China. The delimitation of the new species is further supported by molecular phylogenetic analyses based on eight plastid loci.