Reaction mechanism of surfactant‐sensitized chemiluminescence of bis(2,4,6‐trichlorophyenyl) oxalate and hydrogen peroxide induced by gold nanoparticles

The chemiluminescence (CL) of bis(2,4,6‐trichlorophyenyl) oxalate with hydrogen peroxide in the present of cationic surfactant and gold nanoparticles was studied. The CL emission was obviously enhanced in the presence of surfactant at a suitable concentration, with a synergetic catalysis effect exhibited. Different sizes of gold nanoparticles (15 and 50 nm) showed different effects on CL intensity. Mechanisms of the CL reaction and sensitization effect are discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

Developmentally regulated antigen associated with calcium crystals in tobacco anthers

We have found and characterized an antigen associated with crystal-containing cells in the stomium and connective tissue of the anthers of Nicotiana tabacum L. (tobacco). The antigen, defined by the monoclonal antibody NtF-8B1, localizes to subcellular regions surrounding the crystals. At the light-microscope level, the antigen is detectable just after the first appearance of crystals in the connective tissue of the anther, and at approximately the same time as the appearance of crystals in the stomium. The antigen is not detectable on a Western blot, and gave inconclusive results on a test of periodate sensitivity. It is not the crystals themselves, nor is the presence of the crystals required for antibody recognition. The antigen is sensitive to heat and protease treatment, indicating that it is a protein. The antigen is not tightly membrane-bound, in spite of its localization closely surrounding the crystals. Chemical tests indicate that the druse crystals in the stomium are calcium oxalate.Abbreviations ELISA enzyme-linked immunosorbent assay - FITC fluorescein isothiocyanate This research was supported by a National Science Foundation postdoctoral fellowship to B.L.H., by National Science Foundation grants DMB-87-15799 and to W.E.F. BSR-88-18035, and by U.S. Department of Agriculture grant GAM-89-01056. The authors thank Phillip T. Evans (Louisiana State University, Baton Rouge, USA), Wilma L. Lingle, Harry T. Horner, Jr. (Iowa State University), and A. Jack Fowler, Jr., for advice and helpful discussions.     

Structural aspects of Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] tuberculate ectomycorrhizae

Summary Tubercles of Pseudotsuga menziesii consisted of clusters of ectomycorrhizae surrounded by a peridiumlike rind. Energy dispersive spectroscopy demonstrated that crystals found in the zone of loose hyphae extending from the inner rind to the mantle of each root probably contain calcium oxalate. Inner mantle and Hartig net hyphae showed a labyrinthine branching pattern and stored carbohydrates and protein. The Hartig net formed up to inner cortical cells which had thickened, darkly stained walls. Bacteria were located either along with hyphae within the rind or as colonies on the surface of the tubercle.     

光呼吸代谢物乙醇酸、乙醛酸和草酸对烟草叶片硝酸还原的影响

乙醇酸、乙醛酸和草酸能明显促进烟草(Nicotiana rustica)叶片在黑暗中的硝酸还原,光呼吸抑制剂a-羟基吡啶甲烷磺酸能消除前二者的促进作用而不能完全消除草酸的作用。草酸+NAD~+能显著促进离体的硝酸还原。烟叶提取液加入草酸和NAD~+后生成NADH和CO_2认为活体内由乙醛酸氧化生成的草酸是经脱氢生成NADH供硝酸还原之用。未能证明在烟叶内存在乙醇酸脱氨酶,因此排除由乙醇酸直接脱氢以还原硝酸的可能。     

鸡蛋果叶片细胞质丙酮酸激酶的部分纯化及其调节性质

鸡蛋果叶片细胞质丙酮酸激酶(PK_c)纯化92.6倍.其最适pH为7.2,对热较稳定。PEP的K_m为0.037 mmol/L,ADP的K_m为0.05 mmol/L。ASP、Asn、Cys、α—酮戊二酸和苹果酸均对PK?有轻微的激活作用,但草酸、ATP、CaCl_2则具强烈的抑制作用。     

Selective incorporation of 5-hydroxytryptophan blocks long range electron transfer in oxalate decarboxylase

Oxalate decarboxylase from Bacillus subtilis is a binuclear Mn-dependent acid stress response enzyme that converts the mono-anion of oxalic acid into formate and carbon dioxide in a redox neutral unimolecular disproportionation reaction. A π-stacked tryptophan dimer, W96 and W274, at the interface between two monomer subunits facilitates long-range electron transfer between the two Mn ions and plays an important role in the catalytic mechanism. Substitution of W96 with the unnatural amino acid 5-hydroxytryptophan leads to a persistent EPR signal which can be traced back to the neutral radical of 5-hydroxytryptophan with its hydroxyl proton removed. 5-Hydroxytryptophan acts as a hole sink preventing the formation of Mn(III) at the N-terminal active site and strongly suppresses enzymatic activity. The lower boundary of the standard reduction potential for the active site Mn(II)/Mn(III) couple can therefore be estimated as 740 mV against the normal hydrogen electrode at pH 4, the pH of maximum catalytic efficiency. Our results support the catalytic importance of long-range electron transfer in oxalate decarboxylase while at the same time highlighting the utility of unnatural amino acid incorporation and specifically the use of 5-hydroxytryptophan as an energetic sink for hole hopping to probe electron transfer in redox proteins.     

枸橼酸托法替布片联合仙灵骨葆胶囊对类风湿性关节炎合并骨质疏松患者血清炎症细胞因子、骨强度及骨代谢水平影响

摘要 目的：探讨枸橼酸托法替布片联合仙灵骨葆胶囊对类风湿性关节炎（RA）合并骨质疏松患者血清炎症细胞因子、骨强度及骨代谢水平影响。方法：纳入2021年8月至2022年8月期间徐州医科大学附属连云港医院诊治的80例RA合并骨质疏松患者。根据随机数字表法将患者分为对照组（雷公藤多苷片联合仙灵骨葆胶囊治疗）和实验组（枸橼酸托法替布片联合仙灵骨葆胶囊治疗）,各为40例。对比两组疗效、炎症细胞因子、骨强度及骨代谢指标,观察两组不良反应发生率。结果：实验组的临床总有效率高于对照组（P<0.05）。实验组治疗后巨噬细胞集落刺激因子（M-CSF）、白细胞介素-1β（IL-1β）、环氧合酶-2（COX-2）低于对照组同期（P<0.05）。实验组治疗后横截面积（CSA）、横截面转动惯量（CSMI）、截面系数（Z）、皮质厚度（CT）高于对照组同期（P<0.05）。实验组治疗后骨钙素N端中分子（N-MID）、总Ⅰ型胶原氨基端延长肽（T-PINP）、骨钙素（BGP）、Ⅰ型胶原羧基端前肽（PICP）高于对照组同期,β-胶原降解产物（β-CTX）低于对照组同期（P<0.05）。两组治疗后腰椎骨密度和股骨颈骨密度较治疗前升高,且实验组高于对照组同期（P<0.05）。两组治疗后血沉（ESR）、C反应蛋白（CRP）、类风湿关节炎患者病情（DAS28）评分下降,且实验组低于对照组同期（P<0.05）。两组不良反应发生率组间对比无统计学差异（P>0.05）。结论：枸橼酸托法替布片联合仙灵骨葆胶囊应用于RA合并骨质疏松患者,可有效调节骨代谢水平,增强骨强度,降低血清炎症细胞因子水平。     

Chromium oxalate: A new spin label broadening agent for use with thylakoids

Potassium tris(oxalato)chromate(III) trihydrate (chromium oxalate) has been shown to be a more useful broadening agent than potassium ferricyanide for the spin label 2,2,6,6-tetramethylpiperidine-N-oxy-4-amine (Tempamine) in thylakoid suspensions. Our data show that chromium oxalate is less permeable than ferricyanide, does not inhibit thylakoid electron transport or photophosphorylation, and is not photoreduced by thylakoids.     

Calcium Oxalate Crystal Formation and Growth in Two Legume Species as Altered by Strontium

Young plants of Phaseolus and Canavalia were grown in nutrient solutions where calcium had been partially or totally replaced by either strontium or sodium. The deleterious effect of this replacement on growth and development was greater with strontium than with sodium. As the calcium content of the nutrient solution was decreased fewer calcium oxalate crystals were formed in leaf tissues. There were fewer crystals formed when calcium was replaced by strontium than by sodium. Changes in solubility characteristics of the crystals indicated that they had incorporated strontium.     

Permanent Stained Preparations of Synovial Fluid for Detection of Calcium Compounds Using Alizarin Red S

Permanent preparations of air dried synovial fluids were prepared by staining calcium compounds with alizarin red S stain; each slide was coverslipped with Permount. Variables studied were: (a) concentration of the solution of alizarin red S, (b) pH of staining solution, (c) time of incubation in staining solution and aqueous and ethanolic content of staining solution. The staining effect of each solution was tested on calcium pyrophosphate dihydrate, calcium oxalate, apatite and monosodium urate (MSU). Of all the solutions, best results were obtained with 0.25% alizarin red S in 50% ethanol at pH 7.0 for 30 min. With this solution, the calcium-containing compounds were well stained. MSU did not stain and still preserved negative birefringence on polarizaton. Fixation of smears with ethanol served a double purpose: It fixed the slides without dissolving or removing MSU or the calcium compounds, yet it did dissolve five corticosteroids commonly used for intra-articular injection which may interfere with interpretation of compensated polarized light microscopy of synovial fluids.