PM2.5通过激活NLRP3/Caspse-1通路诱导大鼠子宫炎症反应

颗粒物(PM)对呼吸系统、心血管系统、神经系统和免疫系统均有损害,但目前关于吸入颗粒物对生殖损伤的研究较少。本研究旨在探讨细颗粒物(PM_2.5)短期暴露对大鼠子宫炎症损伤及其作用机制。PM_2.5暴露30 d后,高剂量组大鼠的子宫脏器系数、内膜上皮细胞厚度和腺上皮高度均明显高于对照组(P<0.05),抑制剂MCC950则能明显降低PM_2.5对子宫的影响。子宫组织免疫荧光双染色结果显示,PM_2.5暴露组子宫内CD45白细胞和CD11b巨噬细胞均明显增加(P<0.05)。Elisa法检测子宫组织和血清中白介素1β(IL-1β)和转化生长因子-β1(TGF-β1),暴露组子宫组织和血清中IL-1β和TGF-β1含量明显升高(P<0.05)。Western印迹法检测结果显示,PM_2.5上调核苷酸结合低聚体结构域样受体3 (NLRP3)、凋亡相关斑点样蛋白质(ASC)、pro-IL-1β、pro-Caspase-1和半胱氨酸天冬氨酸蛋白酶-1(Caspase-1)的蛋白质表达量(P<0.05)。与高剂量组相比,NLRP3抑制剂MCC950能明显降低NLRP3/Caspase-1通路中关键蛋白质表达水平(P<0.05)。综上,PM_2.5通过激活NLRP3/ Caspase-1信号,诱导大鼠子宫炎症反应,为PM_2.5生殖毒性预防和治疗提供理论基础。     

植物附生微生物与叶部病害生物防治研究进展

人们早已发现绿色植物叶面(phylloplane)栖居有大量微生物。在一百多年前微生物学家就从植物叶面分离到许多真菌和细菌。1910年Potter首先证实,叶面附生微生物在干扰真菌引起的叶部病害中起着重要作用。至本世纪上半叶,叶面微生物仍为人们所忽视。相反,在这期间土壤微生物得到很大发展,在土传植物病原菌生物防治研究方法上取得了很大进展,为后来的植物叶部病害生物防     

Regulation of ICAM‐1 expression in gingival fibroblasts infected with high‐glucose‐treated P. gingivalis

Porphyromonas gingivalis is a major pathogen in the initiation and progression of periodontal disease, which is recognized as a common complication of diabetes. ICAM‐1 expression by human gingival fibroblasts (HGFs) is crucial for regulating local inflammatory responses in inflamed periodontal tissues. However, the effect of P. gingivalis in a high‐glucose situation in regulating HGF function is not understood. The P. gingivalis strain CCUG25226 was used to study the mechanisms underlying the modulation of HGF ICAM‐1 expression by invasion of high‐glucose‐treated P. gingivalis (HGPg). A high‐glucose condition upregulated fimA mRNA expression in P. gingivalis and increased its invasion ability in HGFs. HGF invasion with HGPg induced increases in the expression of ICAM‐1. By using specific inhibitors and short hairpin RNA (shRNA), we have demonstrated that the activation of p38 MAPK and Akt pathways is critical for HGPg‐induced ICAM‐1 expression. Luciferase reporters and chromatin immunoprecipitation assays suggest that HGPg invasion increases NF‐κB‐ and Sp1‐DNA‐binding activities in HGFs. Inhibition of NF‐κB and Sp1 activations blocked the HGPg‐induced ICAM‐1 promoter activity and expression. The effect of HGPg on HGF signalling and ICAM‐1 expression is mediated by CXC chemokine receptor 4 (CXCR4). Our findings identify the molecular pathways underlying HGPg‐dependent ICAM‐1 expression in HGFs, providing insight into the effect of P. gingivalis invasion in HGFs.     

Influence of solids retention time on membrane fouling: characterization of extracellular polymeric substances and soluble microbial products

The objective of this study was to investigate the influence of solids retention time (SRT) on membrane fouling and the characteristics of biomacromolecules. Four identical laboratory-scale membrane bioreactors (MBRs) were operated with SRTs for 10, 20, 40 and 80 days. The results indicated that membrane fouling occurred faster and more readily under short SRTs. Fouling resistance was the primary source of filtration resistance. The modified fouling index (MFI) results suggested that the more ready fouling at short SRTs could be attributed to higher concentrations of soluble microbial products (SMP). Fourier transform infrared (FTIR) spectra indicated that the SRT had a weak influence on the functional groups of the total extracellular polymeric substances (TEPS) and SMP. However, the MBR under a short SRT had more low-molecular-weight (MW) compounds (<1 kDa) and fewer high-MW compounds (>100 kDa). Aromatic protein and tryptophan protein-like substances were the dominant groups in the TEPS and SMP, respectively.     

Temporal and spatial variability of chlorophyll <Emphasis Type="Italic">a</Emphasis> concentration in Lake Taihu using MODIS time-series data

In order to predict the distribution of chlorophyll a synoptically in Lake Taihu from 2006 to 2008, a common empirical algorithm was developed to relate time series chlorophyll a concentrations in the lake to reflectance derived as a function of band 2 MODIS data (r ² = 0.907, n = 145) using time series from 2005. The empirical model was further validated with chlorophyll a data from a 2008 to 2009 dataset, with RMSE < 7.48 μg l⁻¹ and r ² = 0.978. The seasonal and inter-annual variability of the surface chlorophyll a concentration from 2006 to 2008 was then examined using Empirical Orthogonal Function (EOF) analysis. The results revealed that the first four modes were significant, explaining 54.0% of the total chlorophyll a variance, and indicated that during the summer, algal blooms always occur in the northern bays, Meiliang Bay and Gonghu Bay, while they occur along the southwestern lakeshore during early summer, fall, and even early winter. The inter-annual variance analysis showed that the duration of algal blooms was from April to December of 2007, which was different from the bloom periods in 2006 and 2008. The results of EOF analysis show its potential for long-term integrated lake monitoring, not only in Lake Taihu but also in other large lakes threatened by accelerating eutrophication.     

不同类型杂交水稻组合及其亲本苗期同工酶位点分析

对6个杂交水稻组合及其亲本苗期14种酶的同工酶进行检测,并对其中较为清晰稳定的酶带进行了位点分析,以探讨杂种优势遗传基础。共获得了28个位点的相关资料,包括每个位点的性质、表型多态性和每个位点所编码的酶活性及酶带平均迁移率。所有供试材料在其中25个位点上均未表现出多态性,只有部分组合与其亲本在Est-4、Amy-1、Aat-2等3个位点上存在多态性,其中有81．8％的差异组合其酶带表现出共显性特征。对共显性与杂种优势的关系进行了探讨。     

XC1028 from Xanthomonas campestris adopts a PilZ domain‐like structure without a c‐di‐GMP switch

The crystal structure of XC1028 from Xanthomonas campestris has been determined to a resolution of 2.15 Å using the multiple anomalous dispersion approach. It bears significant sequence identity and similarity values of 64.10% and 70.09%, respectively, with PA2960, a protein indispensable for type IV pilus‐mediated twitching motility, after which the PilZ motif was first named. However, both XC1028 and PA2960 lack detectable c‐di‐GMP binding capability. Although XC1028 adopts a structure comprising a five‐stranded β‐barrel core similar to other canonical PilZ domains with robust c‐di‐GMP binding ability, considerable differences are observed in the N‐terminal motif; XC1028 assumes a compact five‐stranded β‐barrel without an extra long N‐terminal motif, whereas other canonical PilZ domains contain a long N‐terminal sequence embedded with an essential “c‐di‐GMP switch” motif. In addition, a β‐strand (β1) in the N‐terminal motif, running in exactly opposite polarity to that of XC1028, is found inserted into the parallel β3/β1′ strands, forming a completely antiparallel β4↓β3↑β1↓β1′↑ sheet in the canonical PilZ domains. Such dramatic structural differences at the N‐terminus may account for the diminished c‐di‐GMP binding capability of XC1028, and suggest that interactions with additional proteins are necessary to bind c‐di‐GMP for type IV fimbriae assembly. Proteins 2009. © 2008 Wiley‐Liss, Inc.     

韧皮部运输和防御作用的分子机理

韧皮部是维管系统的重要组成部分,在物质运输、信息传递、机械支持以及防御作用中发挥重要作用。近年来,在建立了一系列研究方法的基础上,对韧皮部运输和防御功能特别是碳水化合物装载和卸出机理进行了大量研究,克隆出一些特异基因,初步阐明了韧皮部装载的分子机制,取得可喜进展。本文综述了一些相关研究结果,并提出几个有待解决的问题