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Background
Arthropods are infected by a wide diversity of maternally transmitted microbes. Some of these manipulate host reproduction to facilitate population invasion and persistence. Such parasites transmit vertically on an ecological timescale, but rare horizontal transmission events have permitted colonisation of new species. Here we report the first systematic investigation into the influence of the phylogenetic distance between arthropod species on the potential for reproductive parasite interspecific transfer. 相似文献22.
The rough endoplasmic reticulum (rER) of the cell has an architectural editing function that checks whether protein structure and three-dimensional assembly have occurred properly prior to export of newly synthesized material out of the cell. If these have been faulty, the material is retained within the rER as an inclusion body. Inclusion bodies have been identified previously in chondrocytes and osteoblasts in chondrodysplasias and osteogenesis imperfecta. Inclusion bodies in intervertebral disc cells, however, have only recently been recognized. Our objectives were to use transmission electron microscopy to analyze more fully inclusion bodies in the annulus pulposus and to study the extracellular matrix (ECM) surrounding cells containing inclusion bodies. ECM frequently encapsulated cells with inclusion bodies, and commonly contained prominent banded aggregates of Type VI collagen. Inclusion body material had several morphologies, including relatively smooth, homogeneous material, or a rougher, less homogeneous feature. Such findings expand our knowledge of the fine structure of the human disc cell and ECM during disc degeneration, and indicate the potential utility of ultrastructural identification of discs with intracellular inclusion bodies as a screening method for molecular studies directed toward identification of defective gene products in degenerating discs. 相似文献
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The sand rat, a member of the gerbil family, is a valuable small animal model in which intervertebral disc degeneration occurs spontaneously as the animal ages. Radiographic features of cervical and lumbar degeneration resemble those in human spines. We conducted a retrospective analysis of spines of 140 animals 3?41 months old focusing specifically on the presence of annular tears that are not visible by radiography and have not been described previously in the sand rat disc. During degeneration of the nucleus pulposus, notochordal cell death occurs and granular material, which stains with Alcian blue for proteoglycans, accumulates. Lamellar architecture also deteriorates and annular tears occur that are morphologically similar to the concentric, radiating and transdiscal annular tears in human discs. These tears contain granular material that provides a “marker” that can be used to distinguish the annular tears from artefactual separations during sectioning. We observed lamellar degeneration and separation in the annulus fibrosus at 4 months with associated tears that contained granular material in the nucleus. Tears that contained granular material and displacement of the degenerating nucleus were common in cervical and lumbar discs of animals older than 9 months; some specimens showed tears at 4 and 5 months. With advanced degeneration, granular globules were displaced dorsally adjacent to and into the spinal cord area and also ventrally into regions where osteophytes formed. We present morphologic data that expand the utility of this rodent model of spontaneous age-related disc degeneration and provide novel information on annular tears and disc degeneration. 相似文献
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Karen L Stirrett Julian A Ferreras Sebastian M Rossi Richard L Moy Fabio V Fonseca Luis EN Quadri 《BMC microbiology》2008,8(1):122
Background
Yersinia pestis is the causative agent of plague and a potential agent of bioterrorism and biowarfare. The plague biothreat and the emergence of multidrug-resistant plague underscore the need to increase our understanding of the intrinsic potential of Y. pestis for developing antimicrobial resistance and to anticipate the mechanisms of resistance that may emerge in Y. pestis. Identification of Y. pestis genes that, when overexpressed, are capable of reducing antibiotic susceptibility is a useful strategy to expose genes that this pathogen may rely upon to evolve antibiotic resistance via a vertical modality. In this study, we explored the use of a multicopy suppressor, Escherichia coli host-based screening approach as a means to expose antibiotic resistance determinant candidates in Y. pestis. 相似文献25.
Kristina EN Clark Henry Lopez Bahja Ahmed Abdi Sandra G Guerra Xu Shiwen Korsa Khan Oseme Etomi George R Martin David J Abraham Christopher P Denton Richard J Stratton 《Arthritis research & therapy》2015,17(1)
IntroductionClinical diversity in systemic sclerosis (SSc) reflects multifaceted pathogenesis and the effect of key growth factors or cytokines operating within a disease-specific microenvironment. Dermal interstitial fluid sampling offers the potential to examine local mechanisms and identify proteins expressed within lesional tissue. We used multiplex cytokine analysis to profile the inflammatory and immune activity in the lesions of SSc patients.MethodsDermal interstitial fluid sample from the involved forearm skin, and synchronous plasma samples were collected from SSc patients (n = 26, diffuse cutaneous SSc (DcSSc) n = 20, limited cutaneous SSc (LcSSc) n = 6), and healthy controls (HC) (n = 10) and profiled by Luminex® array for inflammatory cytokines, chemokines, and growth factors.ResultsLuminex® profiling of the dermal blister fluid showed increased inflammatory cytokines (median interleukin ( IL)-6 in SSc 39.78 pg/ml, HC 5.51 pg/ml, p = 0.01, median IL-15 in SSc 6.27 pg/ml, HC 4.38 pg/ml, p = 0.03), chemokines (monocyte chemotactic protein (MCP)-3 9.81 pg/ml in SSc, 7.18 pg/ml HC, p = 0.04), and profibrotic growth factors (platelet derived growth factor (PDGF)-AA 10.38 pg/ml versus 6.94 pg/ml in HC, p = 0.03). In general dermal fluid and plasma cytokine levels did not correlate, consistent with predominantly local production of these factors within the dermal lesions, rather than leakage from the serum. In hierarchical clustering and network analysis IL-6 emerged as a key central mediator.ConclusionsOur data confirm that an immuno-inflammatory environment and aberrant vascular repair are intimately linked to fibroblast activation in lesional skin in SSc. This non-invasive method could be used to profile disease activity in the clinic, and identifies key inflammatory or pro-fibrotic proteins that might be targeted therapeutically. Distinct subgroups of SSc may be defined that show innate or adaptive immune cytokine signatures. 相似文献
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JELENA MLINAREC DRAEN A. PAPE VINJA BESENDORFER 《Botanical journal of the Linnean Society. Linnean Society of London》2006,150(2):177-186
The karyotype of the Mediterranean species Anemone hortensis L. (Ranunculaceae) was characterized with emphasis on heterochromatin distribution and localization of ribosomal (18S−5.8S−26S and 5S rDNA) and telomeric repeats (TTTAGGG). Diploid chromosome complement, 2 n = 2 x = 16, common to all investigated populations, consisted of three acrocentric, one meta-submetacentric and four metacentric chromosomes ranging in size from 6.34 to 10.47 µm. Fluorescence in situ hybridization (FISH) with 18S and 5S rDNA probes revealed two 18S−5.8S−26S rDNA loci on a satellite and secondary constriction of acrocentric chromosome pair 2 and terminally on acrocentric chromosome pair 3, and two 5S rDNA loci in the pericentromeric region of meta-submetacentric chromosome pair 4 and in the proximity of the 18S−5.8S−26S rDNA locus on chromosome pair 2. The only GC-rich heterochromatin, as revealed by fluorochrome Chromomycin A3 staining, was that associated with nucleolar organizer regions, whereas AT-rich heterochromatin, stained with 4,6-diamino-2-phenylindole (DAPI), was distributed intercalarly and terminally on the long arm of all three acrocentric chromosomes, and terminally on chromosomes 4 and 5. FISH with Arabidopsis -type telomeric repeats (TTTAGGG) as a probe revealed two classes of signals, small dot-like and large bands, at chromosome termini exclusively, where they corresponded to terminal DAPI-stained heterochromatin. Heteromorphism of chromosome pair 4, which refers to terminal DAPI bands and FISH signals, was observed in populations of Anemone hortensis . Chromosome pairing during meiosis was regular with formation of localized chiasmata proximal to the centromere. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 150 , 177–186. 相似文献
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This study examines the extent to which interactions among two common alpine/subalpine plant species and their neighbours at the Bogong High Plains in southern Australia are characterized by competition or facilitation. The two target species were Celmisia pugioniformis (Asteraceae) and Carex breviculmis (Cyperaceae). Biotic interactions were examined using vegetation removal manipulations over three growing seasons at five sites across the altitudinal range of tall alpine herbfield communities. Observations recorded growth and mortality. Results for C. pugioniformis clearly indicated facilitation as a dominant process across all sites and seasons. Plants that had their neighbours removed tended to perform worse than plants that had their neighbours left intact. Growth observations for Ca. breviculmis were less clear, but again suggested facilitation. Mortality was distinctly higher among Ca. breviculmis individuals that had their neighbours removed relative to those with neighbours left intact. Results collectively suggest the removal of neighbours acts to reduce growth and increase mortality in C. pugioniformis and Ca. breviculmis throughout the altitudinal range of tall alpine herbfields at the Bogong High Plains. Facilitative and competitive interactions need to be recognized in efforts aimed at mitigating climate change‐associated impacts on the ecology of alpine plant communities. The extent to which biotic interactions may exacerbate or buffer abiotic change is difficult to predict, emphasizing the need for ecological monitoring. 相似文献
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选择内蒙古28个样地采集的10种棘豆属植物56个单株,提取样品的基因组DNA,对其叶绿体psbA trnH序列进行扩增、测序,所得序列利用ClustalX软件进行对位排列,并用MEGA50软件采用最大似然法构建系统发育树。结果显示:(1)10种棘豆属psbA trnH序列的变异位点50个,信息位点36个,种间碱基差异百分率为34%,GC含量变化范围在2318%~2572%之间。(2)棘豆属与黄芪属各为一支,自展支持率达99%,这10种棘豆属植物可能为单系起源。(3)系统树中小叶小花棘豆与小花棘豆的样本独立成一支,支持将小叶小花棘豆作为小花棘豆的变种来处理。(4)多叶棘豆、砂珍棘豆和黄毛棘豆的样本相互混杂,表明亲缘关系很近,支持《内蒙古植物志》将三者归入真棘豆亚属轮叶棘豆组的观点。(5)缘毛棘豆与薄叶棘豆的样本聚成一支,支持将二者归入矮生棘豆组。研究表明,psbA trnH序列可为棘豆属下种间系统发育关系研究提供分子证据。 相似文献
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Marie-Anne Vandenhende Caroline Roussillon Sandrine Henard Philippe Morlat Eric Oksenhendler Hugues Aumaitre Aurore Georget Thierry May Eric Rosenthal Dominique Salmon Patrice Cacoub Dominique Costagliola Geneviève Chêne Fabrice Bonnet the ANRS EN Mortalité study group 《PloS one》2015,10(6)