Copper-Triggered Aggregation of Ubiquitin

Neurodegenerative disorders share common features comprising aggregation of misfolded proteins, failure of the ubiquitin-proteasome system, and increased levels of metal ions in the brain. Protein aggregates within affected cells often contain ubiquitin, however no report has focused on the aggregation propensity of this protein. Recently it was shown that copper, differently from zinc, nickel, aluminum, or cadmium, compromises ubiquitin stability and binds to the N-terminus with 0.1 micromolar affinity. This paper addresses the role of copper upon ubiquitin aggregation. In water, incubation with Cu(II) leads to formation of spherical particles that can progress from dimers to larger conglomerates. These spherical oligomers are SDS-resistant and are destroyed upon Cu(II) chelation or reduction to Cu(I). In water/trifluoroethanol (80∶20, v/v), a mimic of the local decrease in dielectric constant experienced in proximity to a membrane surface, ubiquitin incubation with Cu(II) causes time-dependent changes in circular dichroism and Fourier-transform infrared spectra, indicative of increasing β-sheet content. Analysis by atomic force and transmission electron microscopy reveals, in the given order, formation of spherical particles consistent with the size of early oligomers detected by gel electrophoresis, clustering of these particles in straight and curved chains, formation of ring structures, growth of trigonal branches from the rings, coalescence of the trigonal branched structures in a network. Notably, none of these ubiquitin aggregates was positive to tests for amyloid and Cu(II) chelation or reduction produced aggregate disassembly. The early formed Cu(II)-stabilized spherical oligomers, when reconstituted in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) liposomes and in POPC planar bilayers, form annular and pore-like structures, respectively, which are common to several neurodegenerative disorders including Parkinson's, Alzheimer's, amyotrophic lateral sclerosis, and prion diseases, and have been proposed to be the primary toxic species. Susceptibility to aggregation of ubiquitin, as it emerges from the present study, may represent a potential risk factor for disease onset or progression while cells attempt to tag and process toxic substrates

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Dissolution behavior of simultaneous vapor deposited calcium phosphate coatings in vitro

Solubility is one of the most important properties in the field of biomaterial. The present paper evaluated the dissolution behavior of simultaneous vapor deposited calcium phosphate coatings in vitro. The coatings were immersed in calcium-free Hank's solution at different periods of time. Characterization of the coatings was performed using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and Rutherford backscattering spectroscopy, prior to and after immersion. Amorphous coatings showed complete dissolution. Crystalline coatings showed that alpha tricalcium phosphate (alpha-TCP) phase dissolved steadily throughout the testing time leaving the stable hydroxyapatite phase undegraded. The increased in calcium and phosphate ions due to dissolution of alpha-TCP provided the means for reprecipitation of apatite on the coating, which became apparent after 7days of immersion. (C) 2006 Elsevier B.V. All rights reserved

In vitro study of electron beam deposited calcium phosphate coating in simulated body fluid

Calcium phosphate coatings prepared using the technique of electron beam deposition were immersed in a simulated body fluid for different periods of time to determine their response in vitro. The amorphous as-deposited coatings dissolved completely after a few days of immersion. After annealing in air at 700 degrees C, the dissolution of a small amount of amorphous phase in the crystalline coatings promotes the precipitation of bonelike apatite on the recessed regions by increasing the local supersaturation of calcium and phosphate ions. Formation of apatite was confirmed by the x-ray diffraction peaks at (200), (211), and (203) planes which grew after immersion in simulated body fluid. Fourier transform infrared results conformed to this with the increase in intensity of the absorption band at 1450 cm(-1), signifying the increase in carbonate content. Scanning electron microscopy results showed spherical-shaped apatite nucleated on dissolved surface after 8 days of immersion. Sixteen days after immersion, almost 80 of the surface area was covered with apatite formation and grew to coalesce between neighboring particles forming an integrated platelike layer after 28 days. No obvious detachment between the grown layer and the underlying coating was observed

Distribution and chemical state analysis of iron in the Parkinsonian substantia nigra using synchrotron radiation micro beams

10.1016/S0168-583X(03)01755-5Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms213590-594NIMB

Inomhusklimat i studentbostad : En studie om det termiska inomhusklimatet på Åkarhagsgatan 1 i Västerås

Nowadays most people tend to spend a major part of their lives indoors; therefore, the importance of withholding a good internal environment in our buildings is essential. What follows, the thermal indoor climate is strongly influencing the quality and comfort of life in residential areas. This essay will focus on thermal indoor climate situation in a student residence. Based on calculations, measurements and simulations from two different student apartments as well as data collected through a survey, this work will discuss whether the indoor climate complies with the requirements and standards for student housing and what improvement options are available. The survey showed dissatisfaction with the indoor temperature during summer and wintertime. Furthermore, the climate simulation demonstrated the increase in temperature during the summertime, which resulted in a greater dissatisfaction (PPD). Additionally, the calculations made to compare with the climate simulation have also shown that the apartments are getting too hot during summer. IDA ICE logged the relative humidity over a longer period of 1 year, resulting in a range between 5.8% -77.8%. Own measurements such as temperatures, relative humidity, carbon dioxide and exhaust airflows have been set against standards and requirements from authorities and deficiencies of the thermal indoor climate have been mapped. The apartments meet the standard of thermal indoor climate for student housing with one exception -the carbon dioxide content exceeds 1000 ppm in the apartment with the presence of two people. The exhaust airflow in both apartments was lower in our own measurements in comparison to what they were at the OVK protocol from 2014. The exhaust airflow in one apartment had a flow rate of 10 l / s higher than the dimensional flow rate, which indicates imbalance in the system. According to IDA ICE, too high and too low humidity was observed. This may indicate that the apartments do not have a satisfactory sun shading, which plays a significant role in the indoor climate. Using sun shading on all windows could reduce the temperature increase from solar radiation by 50% and the maximum operating temperature could be lowered by 4 degrees in IDA ICE. Using awnings as the sun shading solutions would also lower PPD's high peaks to 10%