共查询到20条相似文献,搜索用时 15 毫秒
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Victor Kim Michelle Oros Heba Durra Steven Kelsen Mark Aksoy William D. Cornwell Thomas J. Rogers Gerard J. Criner 《PloS one》2015,10(2)
BackgroundGoblet cell hyperplasia is a classic but variable pathologic finding in COPD. Current literature shows that smoking is a risk factor for chronic bronchitis but the relationship of these clinical features to the presence and magnitude of large airway goblet cell hyperplasia has not been well described. We hypothesized that current smokers and chronic bronchitics would have more goblet cells than nonsmokers or those without chronic bronchitis (CB), independent of airflow obstruction.MethodsWe recruited 15 subjects with moderate to severe COPD, 12 healthy smokers, and 11 healthy nonsmokers. Six endobronchial mucosal biopsies per subject were obtained by bronchoscopy and stained with periodic acid Schiff-Alcian Blue. Goblet cell density (GCD) was quantified as goblet cell number per millimeter of basement membrane. Mucin volume density (MVD) was quantified as volume of mucin per unit area of basement membrane.ResultsHealthy smokers had a greater GCD and MVD than nonsmokers and COPD subjects. COPD subjects had a greater GCD than nonsmokers. When current smokers (healthy smokers and COPD current smokers, n = 19) were compared with all nonsmokers (nonsmoking controls and COPD ex-smokers, n = 19), current smokers had a greater GCD and MVD. When those with CB (n = 12) were compared to those without CB (n = 26), the CB group had greater GCD. This finding was also seen in those with CB in the COPD group alone. In multivariate analysis, current smoking and CB were significant predictors of GCD using demographics, lung function, and smoking pack years as covariates. All other covariates were not significant predictors of GCD or MVD.ConclusionsCurrent smoking is associated with a more goblet cell hyperplasia and number, and CB is associated with more goblet cells, independent of the presence of airflow obstruction. This provides clinical and pathologic correlation for smokers with and without COPD. 相似文献
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Geoffrey K. Feld Sahar El-Etr Michele H. Corzett Mark S. Hunter Kamila Belhocine Denise M. Monack Matthias Frank Brent W. Segelke Amy Rasley 《The Journal of biological chemistry》2014,289(44):30668-30679
Francisella tularensis is the etiological agent of tularemia, or rabbit fever. Although F. tularensis is a recognized biothreat agent with broad and expanding geographical range, its mechanism of infection and environmental persistence remain poorly understood. Previously, we identified seven F. tularensis proteins that induce a rapid encystment phenotype (REP) in the free-living amoeba, Acanthamoeba castellanii. Encystment is essential to the pathogen''s long term intracellular survival in the amoeba. Here, we characterize the cellular and molecular function of REP34, a REP protein with a mass of 34 kDa. A REP34 knock-out strain of F. tularensis has a reduced ability to both induce encystment in A. castellanii and invade human macrophages. We determined the crystal structure of REP34 to 2.05-Å resolution and demonstrate robust carboxypeptidase B-like activity for the enzyme. REP34 is a zinc-containing monomeric protein with close structural homology to the metallocarboxypeptidase family of peptidases. REP34 possesses a novel topology and substrate binding pocket that deviates from the canonical funnelin structure of carboxypeptidases, putatively resulting in a catalytic role for a conserved tyrosine and distinct S1′ recognition site. Taken together, these results identify REP34 as an active carboxypeptidase, implicate the enzyme as a potential key F. tularensis effector protein, and may help elucidate a mechanistic understanding of F. tularensis infection of phagocytic cells. 相似文献
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Fernando Pardos 《Acta zoologica》1988,69(1):1-12
Two kinds of cilia have been observed in the pharynx of Glossobalanus minutus Kowalewsky. From the present study, a ciliary specialization can be found in order to move a determinate substance, i.e. mucus or water. Mucus-moving cilia (type I cilia) have a single basal centriole and poorly developed ciliary rootlets. Their tips are rounded, bearing an inner, asymmetrical cap attached to some tubules. Water-moving cilia (type II cilia) are exclusively located at lateral epithelia of branchial bars, giving rise to the water current through the gills. They have two basal centrioles, proximal and distal, and a complex system of ciliary rootlets made up of a principal rootlet, a secondary or accessory rootlet and a 'fan' rootlet. The tips of type II cilia have a long process with some tubules inside. All basal structures are precisely orientated in order to assure a good coordination of ciliary beat. The possible functional significance of ciliary substructure is also discussed. From these observations a model for mucus and water currents through gill slits is postulated. 相似文献
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Zhi Liu Shuang Ding Konstantin Kropachev Jia Lei Shantu Amin Suse Broyde Nicholas E. Geacintov 《PloS one》2015,10(9)
The nucleotide excision repair of certain bulky DNA lesions is abrogated in some specific non-canonical DNA base sequence contexts, while the removal of the same lesions by the nucleotide excision repair mechanism is efficient in duplexes in which all base pairs are complementary. Here we show that the nucleotide excision repair activity in human cell extracts is moderate-to-high in the case of two stereoisomeric DNA lesions derived from the pro-carcinogen benzo[a]pyrene (cis- and trans-B[a]P-N
2-dG adducts) in a normal DNA duplex. By contrast, the nucleotide excision repair activity is completely abrogated when the canonical cytosine base opposite the B[a]P-dG adducts is replaced by an abasic site in duplex DNA. However, base excision repair of the abasic site persists. In order to understand the structural origins of these striking phenomena, we used NMR and molecular spectroscopy techniques to evaluate the conformational features of 11mer DNA duplexes containing these B[a]P-dG lesions opposite abasic sites. Our results show that in these duplexes containing the clustered lesions, both B[a]P-dG adducts adopt base-displaced intercalated conformations, with the B[a]P aromatic rings intercalated into the DNA helix. To explain the persistence of base excision repair in the face of the opposed bulky B[a]P ring system, molecular modeling results suggest how the APE1 base excision repair endonuclease, that excises abasic lesions, can bind productively even with the trans-B[a]P-dG positioned opposite the abasic site. We hypothesize that the nucleotide excision repair resistance is fostered by local B[a]P residue—DNA base stacking interactions at the abasic sites, that are facilitated by the absence of the cytosine partner base in the complementary strand. More broadly, this study sets the stage for elucidating the interplay between base excision and nucleotide excision repair in processing different types of clustered DNA lesions that are substrates of nucleotide excision repair or base excision repair mechanisms. 相似文献
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Effects of Shoot Environment on Apparent Root Resistance to Water Flow in Whole Soybean and Cotton Plants 总被引:1,自引:0,他引:1
The response of leaf water potential to change in transpirationrate was examined in young soybean and cotton plants. Leaf waterpotential measured 1 h after transpiration became constant followinga change in humidity and was constant over a wide range of transpirationrates in both species. However, leaf water potential was notin equilibrium with flow until 3 h after transpiration becameconstant. At equilibrium an increase in transpiration alwaysresulted in a decrease in leaf water potential. It was alsofound that different responses of equilbrium leaf water potentialto transpiration rate occurred depending on whether transpirationwas altered by changing humidity, light intensity, or leaf area.Low light and decreased leaf area caused lower leaf water potentialsfor a given transpiration rate. These increases in root resistancecorrelated with lower rates of root elongation. The data indicatethat shoot-root interactions are occurring which affect apparentroot resistance to water flow, and complicate interpretationof whole plant data on leaf water potential and transpirationin terms of the flow dependence of root hydraulic characteristics. 相似文献
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Cell Wall-Bound Phenolic Acid and Lignin Contents in Date Palm as Related to its Resistance to Fusarium Oxysporum 总被引:5,自引:0,他引:5
The root cell walls of the resistant cultivars of the date palm were more resistant to the action of the cell wall-degrading enzymes (CWDE) of Fusarium oxysporum f. sp. albedinis than those of the susceptible cultivars. Date palm roots contain four cell wall-bound phenolics identified as p-hydroxybenzoic acid, p-coumaric acid, ferulic acid and sinapic acid. The contents of p-coumaric acid and ferulic acid in the resistant cultivars (IKL, SLY, BSTN) were about 2 times higher than those in the susceptible cultivars (BFG, JHL, BSK). The contents of p-hydroxybenzoic acid and sinapic acid in the resistant cultivars were 8.4 and 4.5 times, respectively, higher than those in the susceptible cultivars. The lignin contents in roots of the resistant cultivars were 1.8 times higher than those of the susceptible cultivars. The cell wall-bound phenols accumulated particularly in resistant cultivars reduced strongly the mycelial growth and the CWDE production in vitro. 相似文献
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Catharina Missailidis Jenny H?llqvist Abdel Rashid Qureshi Peter Barany Olof Heimbürger Bengt Lindholm Peter Stenvinkel Peter Bergman 《PloS one》2016,11(1)
Background
The microbial metabolite Trimethylamine-N-oxide (TMAO) has been linked to adverse cardiovascular outcome and mortality in the general population.Objective
To assess the contribution of TMAO to inflammation and mortality in chronic kidney disease (CKD) patients ranging from mild-moderate to end-stage disease and 1) associations with glomerular filtration rate (GFR) 2) effect of dialysis and renal transplantation (Rtx) 3) association with inflammatory biomarkers and 4) its predictive value for all-cause mortality.Methods
Levels of metabolites were quantified by a novel liquid chromatography/tandem mass spectrometry-based method in fasting plasma samples from 80 controls and 179 CKD 3–5 patients. Comorbidities, nutritional status, biomarkers of inflammation and GFR were assessed.Results
GFR was the dominant variable affecting TMAO (β = -0.41; p<0.001), choline (β = -0.38; p<0.001), and betaine (β = 0.45; p<0.001) levels. A longitudinal study of 74 CKD 5 patients starting renal replacement therapy demonstrated that whereas dialysis treatment did not affect TMAO, Rtx reduced levels of TMAO to that of controls (p<0.001). Following Rtx choline and betaine levels continued to increase. In CKD 3–5, TMAO levels were associated with IL-6 (Rho = 0.42; p<0.0001), fibrinogen (Rho = 0.43; p<0.0001) and hsCRP (Rho = 0.17; p = 0.022). Higher TMAO levels were associated with an increased risk for all-cause mortality that remained significant after multivariate adjustment (HR 4.32, 95% CI 1.32–14.2; p = 0.016).Conclusion
Elevated TMAO levels are strongly associated with degree of renal function in CKD and normalize after renal transplantation. TMAO levels correlates with increased systemic inflammation and is an independent predictor of mortality in CKD 3–5 patients. 相似文献13.
Alina V. Brenner Gila Neta Erich M. Sturgis Ruth M. Pfeiffer Amy Hutchinson Meredith Yeager Li Xu Cindy Zhou William Wheeler Margaret A. Tucker Stephen J. Chanock Alice J. Sigurdson 《PloS one》2013,8(3)
Accumulating evidence suggests that alterations in immune function may be important in the etiology of papillary thyroid cancer (PTC). To identify genetic markers in immune-related pathways, we evaluated 3,985 tag single nucleotide polymorphisms (SNPs) in 230 candidate gene regions (adhesion-extravasation-migration, arachidonic acid metabolism/eicosanoid signaling, complement and coagulation cascade, cytokine signaling, innate pathogen detection and antimicrobials, leukocyte signaling, TNF/NF-kB pathway or other) in a case-control study of 344 PTC cases and 452 controls. We used logistic regression models to estimate odds ratios (OR) and calculate one degree of freedom P values of linear trend (PSNP-trend) for the association between genotype (common homozygous, heterozygous, variant homozygous) and risk of PTC. To correct for multiple comparisons, we applied the false discovery rate method (FDR). Gene region- and pathway-level associations (PRegion and PPathway) were assessed by combining individual PSNP-trend values using the adaptive rank truncated product method. Two SNPs (rs6115, rs6112) in the SERPINA5 gene were significantly associated with risk of PTC (PSNP-FDR/PSNP-trend = 0.02/6×10−6 and PSNP-FDR/PSNP-trend = 0.04/2×10−5, respectively). These associations were independent of a history of autoimmune thyroiditis (OR = 6.4; 95% confidence interval: 3.0–13.4). At the gene region level, SERPINA5 was suggestively associated with risk of PTC (PRegion-FDR/PRegion = 0.07/0.0003). Overall, the complement and coagulation cascade pathway was the most significant pathway (PPathway = 0.02) associated with PTC risk largely due to the strong effect of SERPINA5. Our results require replication but suggest that the SERPINA5 gene, which codes for the protein C inhibitor involved in many biological processes including inflammation, may be a new susceptibility locus for PTC. 相似文献
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斯日古楞;王明玖;额尔敦花 《植物研究》2013,33(4):391-397
为了从显微结构上进一步探讨虉草(Phalaris arundinacea L.)的抗旱耐涝性及与利用的关系,于2011年采用常规石蜡切片技术,对其根、茎叶3种营养器官进行解剖观察。结果表明,虉草根的结构自外而内依次为表皮、皮层、维管束鞘、初生韧皮部和初生木质部;茎由表皮、基本组织和维管束构成;叶片内部结构可分为表皮、叶肉和叶脉3部分。根皮层大的细胞间隙和气腔,初生木质部的后生大导管和茎基本组织解体形成的髓腔都是虉草良好的通气组织,是其耐水淹的主要显微特征。茎、叶片角质化的表皮和叶表皮所含的丰富泡状细胞组是虉草具有抗旱性的主要解剖结构特征。叶肉细胞排列紧密且只有少量气孔分布于叶片下表皮,这样的结构可减少蒸腾;叶肉细胞富含叶绿体,增强光合作用,获得更多的同化产物,确保了植株在干旱条件下也有足够的光合产物来维持正常的生理活动。茎、叶维管束部分大量的木纤维起到支撑作用。虉草根的皮层和维管柱部分、茎的基本组织和维管束部分、叶的叶脉部分都含有大面积的厚壁细胞,厚壁细胞中含有丰富的粗纤维和木质素。丰富的粗纤维、木质素等成分则是虉草能成为新能源燃料植物的必备条件。 相似文献
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The current report assessed the effects of low-level proton irradiation in inbred adult male Fischer 344 and Lewis rats performing an analog of the human Psychomotor Vigilance Test (PVT), commonly utilized as an object risk assessment tool to quantify fatigue and sustained attention in laboratory, clinical, and operational settings. These strains were used to determine if genetic differences in dopaminergic function would impact radiation-induced deficits in sustained attention. Exposure to head-only proton irradiation (25 or 100 cGy) disrupted rPVT performance in a strain-specific manner, with 25 cGy-exposed Fischer 344 rats displaying the most severe deficits in sustained attention (i.e., decreased accuracy and increased premature responding); Lewis rats did not display behavioral deficits following radiation. Fischer 344 rats displayed greater tyrosine hydroxylase and dopamine transporter levels in the frontal cortex compared to the Lewis rats, even though radiation exposure increased both of these proteins in the Lewis rats only. Tyrosine hydroxylase was decreased in the parietal cortex of both rat strains following radiation exposure, regardless of proton dose. Strain-specific cytokine changes were also found in the frontal cortex, with the Lewis rats displaying increased levels of putative neurotrophic cytokines (e.g., CNTF). These data support the hypothesis that basal dopaminergic function impacts the severity of radiation-induced deficits in sustained attention. 相似文献
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Increased Expression of Vacuolar Aquaporin and H+-ATPase Related to Motor Cell Function in Mimosa pudica L
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Fleurat-Lessard P Frangne N Maeshima M Ratajczak R Bonnemain JL Martinoia E 《Plant physiology》1997,114(3):827-834
Mature motor cells of Mimosa pudica that exhibit large and rapid turgor variations in response to external stimuli are characterized by two distinct types of vacuoles, one containing large amounts of tannins (tannin vacuole) and one without tannins (colloidal or aqueous vacuole). In these highly specialized cells we measured the abundance of two tonoplast proteins, a putative water-channel protein (aquaporin belonging to the [gamma]-TIPs [tonoplast intrinsic proteins]) and the catalytic A-subunit of H+-ATPase, using either high-pressure freezing or chemical fixation and immunolocalization. [gamma]-TIP aquaporin was detected almost exclusively in the tonoplast of the colloidal vacuole, and the H+-ATPase was also mainly localized in the membrane of the same vacuole. Cortex cells of young pulvini cannot change shape rapidly. Development of the pulvinus into a motor organ was accompanied by a more than 3-fold increase per length unit of membrane in the abundance of both aquaporin and H+-ATPase cross-reacting protein. These results indicate that facilitated water fluxes across the vacuolar membrane and energization of the vacuole play a central role in these motor cells. 相似文献
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The testa structure and histochemistry of Leucaena leucocephalaLam. (De Wit) seed were investigated by bright-field and fluorescencelight microscopy, and scanning electron microscopy. The testaconsisted of several separate layers. Externally there was anon-cellular layer made up of two parts differing in histochemicalcharacteristics: an "outer strip" rich in hydrophilic substances,and a "thicker part" showing the occurrence of phenolics, involvedin water impermeability control. A second underlying thin layerwas formed by the palisade cell caps, joined one to another.This layer, which we called the "cap film ", became metachromaticreddish-blue with Toluidine O pH 4·4 and reacted positivelywith Alcian blue pH 2·5, revealing the presence of polysaccharidehydrophilic material. The palisade cells consisted of two parts,having different structures and histochemical features. Thefurrowed upper part revealed the simultaneous presence of hydrophilicand hydrophobic substances in the furrows and in the ribs respectively.The corresponding periclinal section showed a central daisy-likepattern (made up of hydrophilic material) with a small chainof tiny spots (made up of hydrophobic material) all around it.The inner part of the palisade cells was also furrowed, butshowed only hydrophobic substances of lipidic nature, detectedby Auramine O and Phosphine 3R. The light line was found tobe rich in callose as shown by the strong fluorescence inducedby Aniline Blue. These findings add supporting evidence of thecomplex structure and composition of the Leucaena leucocephalatesta.Copyright 1994, 1999 Academic Press Leucaena leucocephala, testa, structure, histochemistry, water entry 相似文献
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Nick Tolimieri Jameal F. Samhouri Victor Simon Blake E. Feist Phillip S. Levin 《Ecosystems》2013,16(7):1216-1229
Mean trophic level (MTL) is one of the most widely used indicators of marine ecosystem health. It usually represents the relative abundance of fished species across a spectrum of TLs. The reality, ubiquity, and causes of a general decline in the MTL of fisheries catch through time, and whether fisheries catch tracks ecosystem level changes, have engendered much attention. However, the consequences of such patterns for broader ecosystem structure and function remain virtually unexplored. Along the Pacific U.S. Coast, previous work has documented fluctuations and a slow increase in ecosystem MTL from 1977 to 2004. Here, we document a decline in the ecosystem MTL of groundfishes in the same ecosystem from 2003 to 2011, the proximate cause of which was a decrease in the biomass of higher TL groundfishes. Using a food web model, we illustrate how these shifts in ecosystem structure may have resulted in short term, positive responses by many lower TL species in the broader ecosystem. In the longer term, the model predicts that initial patterns of prey release may be tempered in part by lagged responses of other higher TL species, such as salmon and seabirds. Although ecosystem functions related to specific groups like piscivores (excluding high-TL groundfishes) changed, aggregate ecosystem functions altered little following the initial reorganization of biomass, probably due to functional redundancy within the predator guild. Efforts to manage and conserve marine ecosystems will benefit from a fuller consideration of the information content contained within, and implied by, fisheries-independent TL indicators. 相似文献