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.     

Temperature,energy metabolism,and adaptive divergence in two oyster subspecies

Comparisons of related species that have diverse spatial distributions provide an efficient way to investigate adaptive evolution in face of increasing global warming. The oyster subjected to high environmental selections is a model species as sessile marine invertebrate. This study aimed to detect the adaptive divergence of energy metabolism in two oyster subspecies from the genus Crassostrea—C. gigas gigas and C. gigas angulata—which are broadly distributed along the northern and southern coasts of China, respectively. We examined the effects of acute thermal stress on energy metabolism in two oyster subspecies after being common gardened for one generation in identical conditions. Thermal responses were assessed by incorporating physiological, molecular, and genomic approaches. Southern oysters exhibited higher fluctuations in metabolic rate, activities of key energetic enzymes, and levels of thermally induced gene expression than northern oysters. For genes involved in energy metabolism, the former displayed higher basal levels of gene expression and a more pronounced downregulation of thermally induced expression, while the later exhibited lower basal levels and a less pronounced downregulation of gene expression. Contrary expression pattern was observed in oxidative stress gene. Besides, energy metabolic tradeoffs were detected in both subspecies. Furthermore, the genetic divergence of a nonsynonymous SNP (SOD‐132) and five synonymous SNPs in other genes was identified and validated in these two subspecies, which possibly affects downstream functions and explains the aforementioned phenotypic variations. Our study demonstrates that differentiations in energy metabolism underlie the plasticity of adaptive divergence in two oyster subspecies and suggest C. gigas angulata with moderate phenotypic plasticity has higher adaptive potential to cope with exacerbated global warming.     

Five New Guaiane Sesquiterpenes from the Endophytic Fungus Xylaria sp. YM 311647 of Azadirachta indica

Five new guaiane sesquiterpenes, 1 – 5 , were isolated from the culture broth of the endophytic fungus Xylaria sp. YM 311647, isolated from Azadirachta indica A. Juss . The structures of these compounds were elucidated on the basis of spectroscopic analyses, and their inhibitory activities against five pathogenic fungi were evaluated. All guaiane sesquiterpenes showed moderate or weak antifungal activities in a broth microdilution assay.     

停乳链球菌isp基因的克隆与原核表达

根据GenBank报道的停乳链球菌(Streptococcus dysgalactiae)isp基因(GenBank:CP002215.1)序列设计引物,PCR扩增得到isp基因。片段大小为1 500 bp,与从GenBank下载的序列进行同源性比对结果为98.57%。将isp基因克隆于表达载体pET-25b,成功构建了重组质粒pET-25b-isp,将重组质粒分别转化BL21(DE3),将BL21(pET-25b-isp)阳性重组菌株经IPTG诱导后,SDS-PAGE结果显示均有蛋白表达,大小分别为53 ku与目的蛋白大小相符;Western blot检测显示,表达的蛋白为目的蛋白。对成功构建的菌株BL21(pET-25b-isp)表达条件经优化后,在温度37℃,诱导时间12 h,IPTG浓度为1 mmol/L时,蛋白有较高的表达量。     

USP31 acetylation at Lys1264 is essential for its activity and cervical cancer cell growth

Ubiquitin-specific protease 31 (USP31) is a member of deubiquitinase family that is involved in nuclear factor-κB activation and sarcomagenesis.However,little i...     

盐碱胁迫对小麦幼苗生长和根际细菌群落结构的影响

【背景】植物可通过改变根际微生物群落结构来减轻胁迫,但盐碱胁迫下小麦生长和根际细菌群落结构变化尚待明晰。【目的】明确盐碱胁迫下小麦幼苗生长及根际细菌群落结构变化。【方法】以添加NaCl和Na2CO3调节Hoagland营养液Na+浓度和pH来模拟盐碱胁迫,通过MiSeq高通量测序分析细菌群落结构。【结果】与无胁迫对照相比,单纯盐胁迫使小麦幼苗地上和地下部干重、叶绿素和根际土壤速效氮含量分别显著降低了25.0%、57.1%、21.2%和42.9%(P<0.05);小麦幼苗生长指标和根际土壤速效氮、速效磷、有机质含量及酶活性(除过氧化氢酶)随碱度升高而降低;所有处理的小麦幼苗根际优势菌门(丰度7.1%-71.5%)均为变形菌门(Proteobacteria)、放线菌门(Actinobacteria)和厚壁菌门(Firmicutes),优势属(丰度0.5%-5.1%)有肠杆菌属(Enterobacter)、嗜多甲基菌属(Methyloversatilis)、固氮菌属(Azotobacter)、假单胞菌属(Pseudomonas)和异根瘤菌属(Allorhizobium)。盐碱胁迫未显著...     

春小麦对骤旱的响应特征及其阈值分析

与缓慢发展的干旱过程不同,骤旱具有发生速度快,短期内可致害的特点。目前,关于作物骤旱致害的临界阈值及其调控机制尚不清楚。以春小麦为供试作物,通过桶栽试验,模拟研究骤旱过程中小麦受旱致害的过程特征及其控制因素。结果发现,发生骤旱时土壤含水量下降呈先快后慢的变化趋势,叶片水分和叶水势则呈先慢后快的指数变化趋势。叶片光合生理指标对土壤水分的下降存在明显的阈值响应,且不同生理指标的阈值并不完全相同,其中净光合速率与表征叶片光合能力的指标（最大羧化速率）对土壤有效含水量的响应阈值为0.4,气孔导度和蒸腾速率对土壤有效含水量的响应阈值分别为0.5和0.4。而小麦光合生理指标对叶片水分和叶水势的阈值响应并不明显。同时依据各生理指标相关和通径分析结果得出,骤旱发生时引起小麦叶片净光合速率快速降低的主导因子为非气孔因素,而并不是以往作物受旱研究中的气孔因素。本研究结果有望丰富干旱影响认知,并可为科学应对干旱提供依据。     

The role of protein arginine methyltransferase 7 in human developmentally arrested embryos cultured in vitro

Human embryos of in vitro fertilization (IVF) are often susceptible to developmental arrest,which greatly reduces the efficiency of IVF treatment.In recent year...     

诱导神经再生治疗阿尔茨海默病的机制研究进展

阿尔茨海默病(Alzheimer’s disease,AD)是一种以进行性认知障碍和记忆减退为主要特征的中枢神经退行性疾病,已经成为老年医学中最棘手的、亟待解决的问题之一. AD的病理机制仍不清楚,尚无特效治疗药物.目前,探索AD神经再生逐渐成为研究的热点领域,通过诱导神经再生可以有效地改善AD的症状.研究表明,运用药物、物理刺激或干细胞移植方法,可以提高大脑成体神经再生,是延缓AD的病理症状和认知障碍的有效治疗策略.本文综述诱导神经再生的方法及其治疗AD的作用机制,为神经再生治疗实施提供理论依据.     

枯草芽孢杆菌微生态制剂发酵研究进展

微生态制剂是饲用抗生素的绿色有效替代品。枯草芽孢杆菌在逆境中可形成抗逆性强的芽孢,在生产和应用过程中保持高活性,是一种高效的微生态制剂菌种。提高枯草芽孢杆菌活菌数及芽孢率是保证微生态制剂产品质量的关键。本文综述了枯草芽孢杆菌芽孢形成的分子生物学机制及影响芽孢形成的重要因素,进一步比较枯草芽孢杆菌微生态制剂不同发酵方式的特点,重点阐述了提高枯草芽孢杆菌有效生物量的工艺优化,最后介绍了枯草芽孢杆菌微生态制剂的应用,并对将来研究思路进行了讨论。