不同地下水位灰化薹草分解过程中木质素降解与碳、氮、磷释放的关系

为研究湿地植物分解过程中木质素分解与碳、氮、磷元素释放之间的关系及其对不同地下水位环境梯度的响应,在鄱阳湖典型碟形湖泊-白沙湖设置了200 m×300 m分解试验样地,沿地下水位梯度划分4个试验样带(从湖岸到湖心依次为GT-A, GT-B, GT-C, GT-D),采用分解袋法模拟了典型湿地植物灰化薹草在不同地下水位环境的分解过程。结果表明,分解15 d后,地下水位的升高促进了木质素的分解和碳、氮、磷元素的释放;在分解第60—90天,碳、氮、磷元素的相对归还指数随着木质素分解速率的升高而显著增大,并且相关性程度随着分解时间先增强,后减弱;分解过程中土壤pH、含水量和微生物量碳、氮对木质素的分解和碳、氮、磷元素的归还具有显著的促进作用。研究结果将有助于深化对湿地植物分解和生物地球化学循环过程的认识,为湿地自然保护区的科学有效管理提供理论依据。     

Identification of Prolificacy‐Related Differentially Expressed Proteins from Sheep (Ovis aries) Hypothalamus by Comparative Proteomics

Reproduction, as a physiologically complex process, can significantly affect the development of the sheep industry. However, a lack of overall understanding to sheep fecundity has long blocked the progress in sheep breeding and husbandry. In the present study, the aim is to identify differentially expressed proteins (DEPs) from hypothalamus in sheep without FecB mutation in two comparison groups: polytocous (PF) versus monotocous (MF) sheep at follicular phase and polytocous (PL) versus monotocous (ML) sheep at luteal phase. Totally 5058 proteins are identified in sheep hypothalamus, where 22 in PF versus MF, and 39 proteins in PL versus ML are differentially expressed, respectively. A functional analysis is then conducted including Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis to reveal the potential roles of these DEPs. The proteins ENSOARP00000020097, ENSOARP00000006714, growth hormone (GH), histone deacetylase 4 (HDAC4), and 5′‐3′ exoribonuclease 2 (XRN2) in PF versus MF, and bcl‐2‐associated athanogene 4 (BAG4), insulin‐like growth factor‐1 receptor (IGF1R), hydroxysteroid 11‐beta dehydrogenase 1 (HSD11B1), and transthyretin (TTR) in PL versus ML appear to modulate reproduction, presumably by influencing the activities of gonadotropin‐releasing hormone (GnRH). This study provides an alternative method to identify DEPs associated with sheep prolificacy from the hypothalamus. The mass spectrometry data are available via ProteomeXchange with identifier PXD013822.     

Bovine colostrum promoted ileal health in newborn lambs at 24 h after birth: insight from intestinal morphology and innate immunity

The contribution of colostrum to passive immunity transfer and intestinal protection in newborn ruminants is well known; however, it is currently unclear how colostrum intake affects intestinal innate immunity. We investigated the effects of bovine colostrum intake on ileal morphology, expression of genes involved in intestinal innate immunity, and serum concentrations of inflammatory cytokines in newborn lambs. Twenty-seven newborn male Hu lambs were used, of which 18 were bottle-fed either bovine colostrum (C24h; n = 9) or bovine mature milk (M24h; n = 9) within the first 2 h after birth at an intake of approximately 8% of BW; the remaining nine lambs did not receive any feeding (N24h). Blood and ileal tissue samples were collected after the lambs were slaughtered at 24 h after birth. Ileal villus height and villus height-to-crypt depth ratio were significantly higher in C24h than those in N24h and M24h lambs (P < 0.01). Messenger RNA (mRNA) abundance of toll-like receptor (TLR)-2, TLR3, TLR4, TLR6, TLR7, TLR8 and tumour necrosis factor alpha in the ileum was lower in C24h than that in N24h lambs (P < 0.05). Moreover, C24h lambs had a lower TLR3 mRNA abundance (P < 0.01) and a trend of lower TLR6 (P = 0.06) and interleukin 1 beta (P = 0.08) expression compared with those in M24h lambs. We also observed strong positive correlations of tumour necrosis factor alpha expression with that of TLR2 (r = 0.71; P < 0.001), TLR4 (r = 0.88; P < 0.001) and TLR8 (r = 0.83; P < 0.001). Interestingly, the expression of barrier-related molecules, including mucin-13, lysozyme, claudin (CLDN)-1, CLDN2, CLDN4, CLDN7, CLDN12, occludin, zonula occluden-1 and junctional adhesion molecule-1, was consistently lower in C24h lambs than that in N24h and M24h lambs (P < 0.05). These results indicated that the beneficial roles of colostrum intake on intestinal protection in newborn lambs were associated with low TLR expression, which was reflected by improved intestinal development and reduced inflammatory response. Further studies using fluorescence in situ hybridisation and immunohistochemical methods are needed to further explore the mechanisms underlying the lower expression of intestinal barrier-related molecules due to colostrum feeding.     

The Distinct Quorum Sensing Hierarchy of las and rhl in Pseudomonas sp. M18

Pseudomonas sp. M18 is a rhizosphere isolate capable of producing two kinds of antifungal agents: phenazine-1-carboxylic acid (PCA) and pyoluteorin. Recently, the two well-studied quorum sensing (QS) systems of Pseudomonas aeruginosa, LasR/LasI and RhlR/RhlI, have also been identified in this strain. However, in this study, through the use of lacZ translational fusion expression analysis and acyl-homoserine lactone thin-layer chromatography (TLC) bioassays, we clearly display a more complex and distinctive hierarchy of the las and rhl QS systems in strain M18. In this QS cascade, expression of rhlI was negatively controlled by the LasR/LasI QS system. In contrast with lasI, which negatively regulated the rhlR induction, lasR exerted a positive influence on rhlR expression during the log-phase. This interrelationship indicated that the response regulators (LasR and RhlR) of the QS system are expressed independently of their cognate synthases (LasI and RhlI). Furthermore, the las system also modulated the timing and magnitude of the rhlI and rhlR maximal expression. In addition, our data imply that the lasR gene exerts its negative control on PCA production through modulation of rhlI expression. Thus, interactions between the two QS systems are strain specific.     

山东地区盐碱土花生种子际土壤微生物群落结构的研究

【目的】以不同含盐量的滨海盐土、内陆盐碱土和中等肥力非盐碱土壤为实验对象,探讨花生种子在吸水膨胀与萌发过程中,不同类型盐碱土对种子际土壤微生物多样性变化的影响。【方法】采集不同含盐量的滨海盐土、内陆盐碱土和中等肥力非盐碱土壤,通过对各样品中细菌的16S r RNA基因的V3-V4区进行PCR扩增,利用Illumina Hiseq高通量测序技术对12份V3-V4高变区PCR产物进行测序,并对测序数据进行生物信息学分析。【结果】(1)盐碱土壤的种子际细菌群落多样性高于非盐碱土壤,且以东营青坨滨海盐土种子际土壤细菌群落多样性较高。(2)不同类型土壤样本微生物群落结构在纲水平存在明显差异。4种土壤类型种子际土壤细菌共分属于6个菌纲,分别为Proteobacteria、Actinobacteria、Actinobacteria、Bacteroidetes、Acidobacteria和Firmicutes菌纲,并均以Proteobacteria和Actinobacteria菌纲为主要菌纲。全样本菌落结构分析结果表明,4种类型土壤中不同吸胀时间内种子际微生物菌落在门、属水平上的类型和丰度差异最为显著(P0.05)。(3)beta多样性分析和各样本遗传距离(phylogenetic distances)聚类树图分析表明,4个土壤类型的12个土壤样本种子际土壤中微生物群落均可聚为2大类。【结论】土壤含盐量越高其种子际土壤细菌群落多样性较高。不同类型土壤样本微生物群落结构在纲水平存在明显差异,以Proteobacteria和Actinobacteria菌纲为主要菌纲。种子吸胀萌发时间影响种子际微生物菌落在门、属水平上的类型和丰度,但对相同土壤类型样本间遗传距离无影响。     

Pim‐3 is expressed in endothelial cells and promotes vascular tube formation

Pim‐3 is a member of proto‐oncogene Pim family that encodes serine/threonine kinases. Pim proteins regulate both apoptosis and cellular metabolism by phosphorylating their substrates. Here, we report for the first time that Pim‐3 is highly expressed at mRNA and protein levels in endothelial cells (ECs). We found that Pim‐3 is concentrated at the cellular lamellipodia and co‐localized with focal adhesion kinase (FAK). Pim‐3 was dispersed from lamellipodia when ECs were treated with cytochalasin D, an inhibitor of actin polymerization. In addition, small‐interfering RNA (siRNA)‐mediated gene knockdown of Pim‐3 significantly impaired EC spreading, migration, and proliferation, leading to a reduction in tube‐like structure formation in a Matrigel assay. These results provide the novel evidence that Pim‐3 plays an essential role in EC spreading and migration, suggesting that Pim‐3 may be an important molecular target for the development of small‐molecule inhibitors of angiogenesis. J. Cell. Physiol. 220: 82–90, 2009. © 2009 Wiley‐Liss, Inc.     

鸭绿江口近岸海域水质环境对冬季浮游动物群落结构的影响

定量分析滨海湿地近岸海域水质环境与浮游动物群落结构之间的关系对揭示海水水质环境健康状态具有重要意义。2019年12月在鸭绿江口湿地国家级自然保护区近岸海域开展了浮游动物和水环境因子调查,运用冗余分析和结构方程模型等方法探讨了水质环境对冬季浮游动物群落结构的影响。研究区共鉴定出浮游动物14种以及浮游幼虫5大类,桡足类最多占比52.63%;保护区不同功能分区间浮游动物群落结构总体差异不大,多样性指数、均匀度指数和丰富度指数平均值分别为1.34、0.51和0.59;浮游动物的种群分布与海水化学需氧量、溶解性无机氮、浮游植物群落多样性指数和铜元素含量关系显著;结构方程模型模拟结果表明,海水富营养化水平对浮游动物丰富度的效应系数为-0.26,具有显著的直接影响(P=0.01),重金属污染水平通过影响浮游植物丰富度(效应系数为-0.41,P<0.001)间接对浮游动物丰富度产生作用(间接效应系数为-0.2)。研究结果将有助于深化对海水环境和浮游动物群落结构协同演变过程的认识,为滨海湿地近岸海洋生态系统科学管理提供理论支撑。     

Targeted cowpea chlorotic mottle virus-based nanoparticles with tumor-homing peptide F3 for photothermal therapy

Our aim was to devise targeted drug delivery systems using genetically modified cowpea chlorotic mottle virus (CCMV) capsids by fusion expression with tumorhoming peptide F3 for efficient delivery of therapeutic substances into tumor cells. The RNA-binding domain at the N terminus (amino acid residues 1–25) of CCMV capsid protein (CP) was selectively deleted, and F3 was inserted for the expression in Pichia pastoris. After chromatographic purification, F3-CCMV capsids were obtained via selfassembly of the F3-CP fusion protein and then analyzed by transmission electron microscopy and dynamic light scattering analysis, which revealed spherical nanoparticles (NPs) ca. 18 nm in diameter with regular monodispersity. Near-infrared fluorescent dye IR780 iodide, which has been applied for cancer imaging, photodynamic therapy, and photothermal therapy, was encapsulated in F3-CCMV NPs. The resultant F3-CCMV-IR780 NPs showed excellent molecular targeting to nucleolin receptor overexpressed on the surface of MCF-7 tumor cells. Furthermore, the in vitro cellular uptake and cell viability assay proved a photothermal effect by a single dose of near-infrared laser irradiation. The present system may offer a programmable nanoscaffoldbased drug delivery system vehicle for fabrication of promising therapeutic substances for cancer therapy.