S100和GFAP在猫上丘表浅层表达差异的免疫组织化学观察

目的比较青、老年猫上丘表浅层（superricial Superior Colliculus,sSC）星形胶质细胞中S100蛋白与胶质原纤维酸性蛋白（glial fibrillary acidic protein,GFAP）表达的老年性变化,并探讨其在动物视觉功能衰退中的意义。方法采用免疫组织化学方法（SABC法）示青、老年猫上丘表浅层S100免疫阳性反应（S100-immunoreactive,S100-IR）细胞及胶质纤维酸性蛋白免疫反应阳性（GFAP-immunoreactive,GFAP-IR）细胞。光镜下观察、拍照,并利用Image-ProExpress图像分析软件对上丘表浅层各层S100和GFAP免疫反应阳性细胞密度及其灰度值进行测量。结果与青年猫相比,老年猫上丘表浅层中S100蛋白与GFAP表达均有不同程度的显著增强（P〈0.01）。结论衰老进程中,上丘表浅层出现S100、GFAP表达增强,星形胶质细胞存在明显的反应性活化与增生,这对维持上丘表浅层神经元的活性和神经元之间的通讯联系,从而延缓老年性视觉功能衰退具有重要意义。     

Development of Fatal Intestinal Inflammation in MyD88 Deficient Mice Co-infected with Helminth and Bacterial Enteropathogens

Infections with intestinal helminth and bacterial pathogens, such as enteropathogenic Escherichia coli, continue to be a major global health threat for children. To determine whether and how an intestinal helminth parasite, Heligomosomoides polygyrus, might impact the TLR signaling pathway during the response to a bacterial enteropathogen, MyD88 knockout and wild-type C57BL/6 mice were infected with H. polygyrus, the bacterial enteropathogen Citrobacter rodentium, or both. We found that MyD88 knockout mice co-infected with H. polygyrus and C. rodentium developed more severe intestinal inflammation and elevated mortality compared to the wild-type mice. The enhanced susceptibility to C. rodentium, intestinal injury and mortality of the co-infected MyD88 knockout mice were found to be associated with markedly reduced intestinal phagocyte recruitment, decreased expression of the chemoattractant KC, and a significant increase in bacterial translocation. Moreover, the increase in bacterial infection and disease severity were found to be correlated with a significant downregulation of antimicrobial peptide expression in the intestinal tissue in co-infected MyD88 knockout mice. Our results suggest that the MyD88 signaling pathway plays a critical role for host defense and survival during helminth and enteric bacterial co-infection.     

Notch inhibition promotes fetal liver stem/progenitor cells differentiation into hepatocytes via the inhibition of HNF-1β

In a previous study, the Notch pathway inhibited with N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (also called DAPT) was shown to promote the differentiation of fetal liver stem/progenitor cells (FLSPCs) into hepatocytes and to impair cholangiocyte differentiation. The precise mechanism for this, however, was not elucidated. Two mechanisms are possible: Notch inhibition might directly up-regulate hepatocyte differentiation via HGF (hepatocyte growth factor) and HNF (hepatocyte nuclear factor)-4α or might impair cholangiocyte differentiation thereby indirectly rendering hepatocyte differentiation as the dominant state. In this study, HGF and HNF expression was detected after the Notch pathway was inhibited. Although our initial investigation indicated that the inhibition of Notch induced hepatocyte differentiation with an efficiency similar to the induction via HGF, the results of this study demonstrate that Notch inhibition does not induce significant up-regulation of HGF or HNF-4α in FLSPCs. This suggests that Notch inhibition induces hepatocyte differentiation without the influence of HGF or HNF-4α. Moreover, significant down-regulation of HNF-1β was observed, presumably dependent on an impairment of cholangiocyte differentiation. To confirm this presumption, HNF-1β was blocked in FLSPCs and was followed by hepatocyte differentiation. The expression of markers of mature cholangiocyte was impaired and hepatocyte markers were elevated significantly. The data thus demonstrate that the inhibition of cholangiocyte differentiation spontaneously induces hepatocyte differentiation and further suggest that hepatocyte differentiation from FLSPCs occurs at the expense of the impairment of cholangiocyte differentiation, probably being enhanced partially via HNF-1β down-regulation or Notch inhibition.     

Differential promoter activities of functional haplotypes in the 5′‐flanking region of human Sulfotransferase 1A1

Previously, we reported five common single nucleotide polymorphisms (SNPs), ?624G>C, ?396G>A, ?358A>C, ?341C>G, and ?294T>C, and six common haplotypes (CGACT, GAACT, GGAGC, GGACC, CAACT, and GAACC) in the 5′‐flanking region of the SULT1A1 gene that were associated with altered enzymatic activity. In the present study, we performed in vitro assays to determine the functional impact of these genetic variations on the promoter activity. Dual luciferase reporter assays revealed that these SNPs are located in a negative regulatory fragment of the SULT1A1 gene. Further experiments demonstrated that these SNPs and haplotypes affected promoter activities of SULT1A1. Electrophoretic mobility shift assays showed distinctive binding patterns for the SNPs ‐396G>A and ‐294T>C, due to differential binding affinities of the G/A alleles and the T/C alleles to nuclear proteins extracted from the liver carcinoma cell lines, HepG2 and Huh7. © 2012 Wiley Periodicals, Inc. J Biochem Mol Toxicol 26:422–428, 2012; View this article online at wileyonlinelibrary.com . DOI 10:1002/jbt.21437     

2ME and 2OHE2 exhibit growth inhibitory effects and cell cycle arrest at G2/M in RL95-2 human endometrial cancer cells through activation of p53 and Chk1

Evidence is accumulating that estradiol (E2) may play a dual role in carcinogenic and anticarcinogenic effects by different metabolic pathways. It has been shown that some metabolites of E2 exert proliferative and others anti-proliferative properties on human cancer cells. In the present study, the effects of E2 and its four primary metabolites including 2-hydroxyestradiol (2OHE2), 4-hydroxyestradiol (4OHE2), 2-methoxyestradiol (2ME), and 4-methoxyestradiol (4ME) on proliferation and cell cycle in RL95-2 human endometrial cells were investigated. Our results indicate that 2ME and 2OHE2, but not E2, 4ME, and 4OHE2, exhibit the inhibitory effect through cell cycle arrest at G2/M. 2ME and 2OHE2-induced G2/M cell cycle arrest associated with activation of p53 (Ser15), upregulation of p21(WAF1/Cip1) (p21) and GADD45, inactivation of Cdc2 (Tyr15), as well as downregulation of Cyclin B1. 2ME and 2OHE2-mediated cell cycle arrest at G2/M was also related to activation of protein kinase Chk1 which is associated with p53 (Ser20) activation and downstream responses.     

Paenibacillus polymyxa SQR-21 systemically affects root exudates of watermelon to decrease the conidial germination of Fusarium oxysporum f.sp. niveum

Paenibacillus polymyxa SQR-21 has been identified as a potential agent for the biocontrol of Fusarium wilt in watermelon, which is caused by the pathogenic fungus Fusarium oxysporum f.sp. niveum (FON). In the present study, the effects of root exudates from watermelon plants inoculated or non-inoculated with either SQR-21 or FON on conidial germination of FON were investigated. Compared to the control, conidial germination was decreased with root exudates from SQR-21-inoculated plants, but conidial germination was enhanced by root exudates from FON-inoculated plants. Maximal germination was found with root exudates from FON-inoculated plants after 30 d, which was 1.35 times more germination than the control. A split-root system was designed to verify that the alterations of the exudation pattern in SQR-21- inoculated or FON-inoculated watermelon roots were not only local, but also systemic. Cinnamic acid was found in the watermelon root exudates. An assay to test the effects of cinnamic acid on conidial germination of FON revealed that the stimulation of conidial germination was observed from cinnamic acid concentrations ranging from 0 to 30 μg/ml. In conclusion, both of SQR-21 and FON systemically affects watermelon root exudates. These results will help to the better understanding of the plant-microbe communication and will guide to improve the biocontrol strategies against Fusarium wilt of watermelon plants.     

基于i-Tree模型的城市森林经济效益评估

城市森林的生态服务功能对改善城市环境质量具有重要作用,如何量化这些生态服务功能是使城市森林发挥最大效益的一个重要前提.随着科学的发展,对城市森林经济效益评估的量化方法已由传统的CTLA法、Burnley法、碳税法、造林成本法等发展到模型测算法.本文介绍的i-Tree模型是由美国林务局(USDA Forest Service)于2006年开发的城市森林效益评估软件,具有许多其他模型如CITY green模型等不可替代的优势,在国际城市森林研究中已得到了广泛的应用,但国内尚未推广.本文主要阐述和评价了模型中UFORE和STRATUM两个主要模块的研究及应用进展,通过作者在国内的应用实践,讨论了该模型在中国的应用前景及存在的主要问题,为城市森林管理提供科学依据.