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51.
Simone Kurz Chunsheng Jin ) Alba Hykollari Daniel Gregorich Barbara Giomarelli Gerardo R. Vasta Iain B. H. Wilson Katharina Paschinger 《The Journal of biological chemistry》2013,288(34):24410-24428
The eastern oyster (Crassostrea virginica) has become a useful model system for glycan-dependent host-parasite interactions due to the hijacking of the oyster galectin CvGal1 for host entry by the protozoan parasite Perkinsus marinus, the causative agent of Dermo disease. In this study, we examined the N-glycans of both the hemocytes, which via CvGal1 are the target of the parasite, and the plasma of the oyster. In combination with HPLC fractionation, exoglycosidase digestion, and fragmentation of the glycans, mass spectrometry revealed that the major N-glycans of plasma are simple hybrid structures, sometimes methylated and core α1,6-fucosylated, with terminal β1,3-linked galactose; a remarkable high degree of sulfation of such glycans was observed. Hemocytes express a larger range of glycans, including core-difucosylated paucimannosidic forms, whereas bi- and triantennary glycans were found in both sources, including structures carrying sulfated and methylated variants of the histo-blood group A epitope. The primary features of the oyster whole hemocyte N-glycome were also found in dominin, the major plasma glycoprotein, which had also been identified as a CvGal1 glycoprotein ligand associated with hemocytes. The occurrence of terminal blood group moieties on oyster dominin and on hemocyte surfaces can account in part for their affinity for the endogenous CvGal1. 相似文献
52.
Shoko Shinya Takayuki Ohnuma Reina Yamashiro Hisashi Kimoto Hideo Kusaoke Padmanabhan Anbazhagan André H. Juffer Tamo Fukamizo 《The Journal of biological chemistry》2013,288(42):30042-30053
Two carbohydrate binding modules (DD1 and DD2) belonging to CBM32 are located at the C terminus of a chitosanase from Paenibacillus sp. IK-5. We produced three proteins, DD1, DD2, and tandem DD1/DD2 (DD1+DD2), and characterized their binding ability. Transition temperature of thermal unfolding (Tm) of each protein was elevated by the addition of cello-, laminari-, chitin-, or chitosan-hexamer (GlcN)6. The Tm elevation (ΔTm) in DD1 was the highest (10.3 °C) upon the addition of (GlcN)6 and was markedly higher than that in DD2 (1.0 °C). A synergistic effect was observed (ΔTm = 13.6 °C), when (GlcN)6 was added to DD1+DD2. From isothermal titration calorimetry experiments, affinities to DD1 were not clearly dependent upon chain length of (GlcN)n; ΔGr° values were −7.8 (n = 6), −7.6 (n = 5), −7.6 (n = 4), −7.6 (n = 3), and −7.1 (n = 2) kcal/mol, and the value was not obtained for GlcN due to the lowest affinity. DD2 bound (GlcN)n with the lower affinities (ΔGr° = −5.0 (n = 3) ∼ −5.2 (n = 6) kcal/mol). Isothermal titration calorimetry profiles obtained for DD1+DD2 exhibited a better fit when the two-site model was used for analysis and provided greater affinities to (GlcN)6 for individual DD1 and DD2 sites (ΔGr° = −8.6 and −6.4 kcal/mol, respectively). From NMR titration experiments, (GlcN)n (n = 2∼6) were found to bind to loops extruded from the core β-sandwich of individual DD1 and DD2, and the interaction sites were similar to each other. Taken together, DD1+DD2 is specific to chitosan, and individual modules synergistically interact with at least two GlcN units, facilitating chitosan hydrolysis. 相似文献
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54.
探讨北虫草复合制剂对小鼠免疫功能的调节作用。建立小鼠免疫力降低的动物模型,实验分6组:对照组、衰老/免疫抑制模型组、白介素-2(IL-2)和北虫草复合制剂的不同剂量组。采用称重法测定免疫器官重量,计算胸腺指数和脾指数。小鼠溶血素抗体生成采用绵羊红细胞致敏法。北虫草复合制剂对小鼠脾脏指数和胸腺指数的影响:实验组(50.2±2.4与27.6±3.6)明显高于模型组(45.6±4.8与23.6±3.6),单位:(mg/10 g体重),差异有显著性(P<0.05)。对小鼠溶血素抗体生成的影响:实验组(53.53±7.8)高于药物对照组(36.50±7.3)。北虫草复合制剂能恢复衰老小鼠的胸腺指数和脾脏指数,增强免疫抑制小鼠血清溶血素含量,因此,对免疫功能低下的小鼠模型具有免疫调节作用。 相似文献
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56.
核糖体是抗生素的主要靶点,而获得足量高纯度的核糖体是进行结构和药物研究的基础。结核分枝杆菌壁厚且生长缓慢,制备足量高纯度的核糖体具有挑战性。本研究改进并优化了核糖体纯化制备方法,通过大量培养和安全处理致病菌,应用高效破碎厚壁革兰阳性菌的技术,结合传统的蔗糖密度离心分离和蛋白液相色谱纯化技术,经多步纯化和分离,获得了高纯度和较高产率的耻垢分枝杆菌与结核分枝杆菌的核糖体样品,为后续生化实验和结构生物学研究提供了保证。该分枝杆菌核糖体制备方法也可应用于其他革兰阳性致病菌复合物样品的直接提纯,以及复合物特异性的进一步研究,特别是利用晶体学与冷冻电镜结合的高精度复合物结构研究,有助于揭示细菌耐药性机制及用于新型抗生素的研发。 相似文献
57.
Conveying Advanced Li‐ion Battery Materials into Practice The Impact of Electrode Slurry Preparation Skills 下载免费PDF全文
Li‐ion batteries (LIB's) are of the greatest practical utility for portable electronics and electric vehicles (EV's). LIB energy, power and cycle life performances depend on cathode and anode compositions and morphology, electrolyte composition and the overall cell design. Electrode morphology is influenced by the shape and size of the active material (AM), conductive additive (CA) particles, the polymeric binder properties, and also on the AM/CA/binder mass ratio. At the same time, it also substantially depends on the electrode preparation process. This process is usually comprised of mixing a solvent, a binder, AM and CA powders, and casting the resulting slurry onto a current collector foil followed by a drying process. Whereas the problems of electrode morphology and their influence on the LIB‐electrode performance always receive a proper attention, the influence of slurry properties and slurry preparation techniques on the electrode morphology is often overlooked or at least underrated. The present work summarizes the current state‐of‐the‐art in the field of LIB‐electrode precursor slurries preparation, characterized by multicomponent compounds and large variations in sizes and shapes of the solid components. Approaches to LIB‐electrode slurry preparation are outlined and discussed in the context of the ultimate LIB‐electrode morphology and performance. 相似文献
58.
Benchmarking sample preparation/digestion protocols reveals tube‐gel being a fast and repeatable method for quantitative proteomics 下载免费PDF全文
Sample preparation, typically by in‐solution or in‐gel approaches, has a strong influence on the accuracy and robustness of quantitative proteomics workflows. The major benefit of in‐gel procedures is their compatibility with detergents (such as SDS) for protein solubilization. However, SDS‐PAGE is a time‐consuming approach. Tube‐gel (TG) preparation circumvents this drawback as it involves directly trapping the sample in a polyacrylamide gel matrix without electrophoresis. We report here the first global label‐free quantitative comparison between TG, stacking gel (SG), and basic liquid digestion (LD). A series of UPS1 standard mixtures (at 0.5, 1, 2.5, 5, 10, and 25 fmol) were spiked in a complex yeast lysate background. TG preparation allowed more yeast proteins to be identified than did the SG and LD approaches, with mean numbers of 1979, 1788, and 1323 proteins identified, respectively. Furthermore, the TG method proved equivalent to SG and superior to LD in terms of the repeatability of the subsequent experiments, with mean CV for yeast protein label‐free quantifications of 7, 9, and 10%. Finally, known variant UPS1 proteins were successfully detected in the TG‐prepared sample within a complex background with high sensitivity. All the data from this study are accessible on ProteomeXchange (PXD003841). 相似文献
59.
Vera Y. Chung Rebecca Konietzny Philip Charles Benedikt Kessler Roman Fischer Benjamin W. Turney 《Fly》2016,10(2):91-100
Kidney stone disease is a major health burden with a complex and poorly understood pathophysiology. Drosophila Malpighian tubules have been shown to resemble human renal tubules in their physiological function. Herein, we have used Drosophila as a model to study the proteomic response to crystal formation induced by dietary manipulation in Malpighian tubules. Wild-type male flies were reared in parallel groups on standard medium supplemented with lithogenic agents: control, Sodium Oxalate (NaOx) and Ethylene Glycol (EG). Malpighian tubules were dissected after 2 weeks to visualize crystals with polarized light microscopy. The parallel group was dissected for protein extraction. A new method of Gel Assisted Sample Preparation (GASP) was used for protein extraction. Differentially abundant proteins (p<0.05) were identified by label-free quantitative proteomic analysis in flies fed with NaOx and EG diet compared with control. Their molecular functions were further screened for transmembrane ion transporter, calcium or zinc ion binder. Among these, 11 candidate proteins were shortlisted in NaOx diet and 16 proteins in EG diet. We concluded that GASP is a proteomic sample preparation method that can be applied to individual Drosophila Malpighian tubules. Our results may further increase the understanding of the pathophysiology of human kidney stone disease. 相似文献
60.
黄土丘陵区坡面整地和植被耦合下的土壤水分特征 总被引:7,自引:0,他引:7
水分是干旱半干旱地区植被恢复的主要环境制约因子。在黄土高原小流域,合理整地能够有效截留降雨补给土壤水,进而促进植被恢复。选择地处甘肃定西的半干旱黄土小流域为研究区,基于野外实测数据,分析不同植被和整地方式(柠条水平阶、山杏水平沟、侧柏反坡台,油松反坡台)综合影响下的土壤水分特征。采用最优分割法将不同整地方式土壤水分垂直层次划分为活跃层,次活跃层和相对稳定层。结果表明:生长季不同整地方式土壤水分的变化与降水量的变化密切相关,不同月份以及不同深度各整地方式土壤水分之间差异显著(P0.05)。根据土壤水分垂直变化特征,山杏水平沟水分活跃层与次活跃层为0—80cm,其深度范围均大于其他3种整地方式,而柠条水平阶土壤水分均在30 cm以下较为稳定,其深度范围均小于其他3种整地方式。不同整地方式土壤水分含量具体表现为:山杏水平沟侧柏反坡台柠条水平阶油松反坡台。 相似文献