Transmission electron microscopy characterization of fluorescently labelled amyloid β 1-40 and α-synuclein aggregates

<p>Abstract</p> <p>Background</p> <p>Fluorescent tags, including small organic molecules and fluorescent proteins, enable the localization of protein molecules in biomedical research experiments. However, the use of these labels may interfere with the formation of larger-scale protein structures such as amyloid aggregates. Therefore, we investigate the effects of some commonly used fluorescent tags on the morphologies of fibrils grown from the Alzheimer's disease-associated peptide Amyloid β 1-40 (Aβ40) and the Parkinson's disease-associated protein α-synuclein (αS).</p> <p>Results</p> <p>Using transmission electron microscopy (TEM), we verify that N-terminal labeling of Aβ40 with AMCA, TAMRA, and Hilyte-Fluor 488 tags does not prevent the formation of protofibrils and amyloid fibrils of various widths. We also measure the two-photon action cross-section of Aβ40 labelled with Hilyte Fluor 488 and demonstrate that this tag is suitable for use with two-photon fluorescence techniques. Similarly, we find that Alexa Fluor 488 labelling of αS variant proteins near either the N or C terminus (position 9 or 130) does not interfere with the formation of amyloid and other types of αS fibrils. We also present TEM images of fibrils grown from αS C-terminally labelled with enhanced green fluorescent protein (EGFP). Near neutral pH, two types of αS-EGFP fibrils are observed via TEM, while denaturation of the EGFP tag leads to the formation of additional species.</p> <p>Conclusions</p> <p>We demonstrate that several small extrinsic fluorescent tags are compatible with studies of amyloid protein aggregation. However, although fibrils can be grown from αS labelled with EGFP, the conformation of the fluorescent protein tag affects the observed aggregate morphologies. Thus, our results should assist researchers with label selection and optimization of solution conditions for aggregation studies involving fluorescence techniques.</p

1964

Turf Management Club by John Traynor (page 1) Who Is Superintendent Here by H.E. Frenette (1) Good Turf Can Result from good Sodding (3) Golf Course Superintendent by Edwart Wiacek (4) Picture - Outstanding Senior Prof. Troll Picture - recognition for Blazers St. Andrew\u27s, Scotland by William Hynd (5) Analogy of a Turf Manager by James B. Cole (6) Fish Trouble by Peter A. Langelier and Dennis P. Leger (8) Square Rings by Robert P. McGuire (9) A Different Type of Course by Robert Hall (10) Literature by Pierre Coste (11) Weeds in Golf Course Turf and Their Control by John F. Cornman (A-1) The USe of Liquid Fertilizer by Anthony B. Longo (A-3) Fertilizing a Golf Course Through an Irrigation System by Herbert E. Berg (A-6) The Extent of Winter Injury on Golf Courses by James L. Holmes (A-11) The Problem of Winter Injury by James B. Beard (A-13) Establishing, Maintaining, and Selling Sod for Turf Areas in New England by George F. Stewart (A-20) Problems of Maintaining Turf Around Industrial Grounds by George Moore (A-22) Landscaping Industrial sites by A.W. Boicourt (A-25) Introduction to the panel Discussion on Grasses for Tees and Their Management by Alexander M. Radko (A-28) Building a Golf Tee by Phil Cassidy (A-29) Grasses for Tees and Their Management by Wm. Dest (A-31) Golf Course Tee maintenance by Jim Fulwider (A-32) Tees by F. Thompson (A-33) How to Draw up a Contract by Lawrence D. Rhoades (A-34) My Contract by Lucien E. Duval (A-37) The Golf Car Problem by Geoffrey S. Cornish (A-41) Golf Cars and Turfgrass by Lee Record (A-42) Course Design and Golf Cars by William F. Mitchell (A-42) Golf Cars and the Established Course by Sherwood Moore (A-45) Course Design and Golf Cars by Phil Wogan (a-52) Introduction of Cars to the New Course by M. Ovian (A-56

Greenland ice sheet surface mass loss: recent developments in observation and modeling

Surface processes currently dominate Greenland ice sheet (GrIS) mass loss. We review recent developments in the observation and modelling of GrIS surface mass balance (SMB), published after the July 2012 deadline for the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5). Since IPCC AR5 our understanding of GrIS SMB has further improved, but new observational and model studies have also revealed that temporal and spatial variability of many processes are still poorly quantified and understood, e.g. bio-albedo, the formation of ice lenses and their impact on lateral meltwater transport, heterogeneous vertical meltwater transport (‘piping’), the impact of atmospheric circulation changes and mixed-phase clouds on the surface energy balance and the magnitude of turbulent heat exchange over rough ice surfaces. As a result, these processes are only schematically or not at all included in models that are currently used to assess and predict future GrIS surface mass loss

Spectral diversity and photometric behavior of main-belt and near-Earth vestoids and (4) Vesta: A study in preparation for the Dawn encounter

In anticipation of the Dawn Mission to 4 Vesta, we conducted a ground-based campaign of Bessel BVRI filter photometry of five V-type near-Earth asteroids over a wide range of solar phase angles. We also obtained medium-resolution optical spectroscopy (0.38 μm < λ < 0.92 μm; R ∼ 500) of sixteen near-Earth and main-belt V-type asteroids in order to investigate their spectral diversity and to draw connections between spacecraft data of Vesta and V-type asteroids. Our disk-integrated photometry extended the excursion in solar phase angle beyond the maximum of 24° available from Earth for Vesta to 87°, which is more typical of the geometry during the Dawn approach and mapping phases. The majority of our broad-band observations were obtained at the JPL 0.6-m Table Mountain Observatory but multiple nights were also contributed by the Calar Alto 1.2-m and 2.2-m telescopes, as well as by the Purple Mountain 1-m Schmidt. Our results include a determination of rotation periods for 4 asteroids, identification of a binary candidate and four new V-type asteroids, including a confirmation of two main-belt V-type asteroids beyond the Jupiter 1:3 resonance (Cruikshank, D.P., Tholen, D.J., Bell, J.F., Hartmann, W.K., Brown, R.H. [1991]. Icarus 89, 1–13; Lazzaro, D. et al. [2000]. Science 288, 2033–2035; Roig, F., Gil-Hutton, R. [2006]. Icarus 183(2), 411–419; Moskovitz, N.A., Jedicke, R., Gaidos, E., Willman, M., Nesvorný, D., Fevig, R., Ivezić, Ž. [2008]. Icarus 198, 77–90). This latter finding supports the hypothesis that some vestoids may be crustal fragments of a disrupted basaltic parent body compositionally similar to 4 Vesta. We also obtained rotationally resolved medium resolution spectra of Vesta during the Dawn orbit insertion phase, which will be valuable for calibration and comparison of spacecraft data. Modeling of a composite V-type asteroid phase curve yielded a generic photometric model for V asteroids. We also find that a significant amount of the spectral diversity in the V class comes from changes in solar phase angle. A fit of a composite solar phase curve containing our vestoid observations, previously published groundbased observations of Vesta, and early disk-integrated Dawn observations show important differences with other asteroids. The macroscopic surface roughness of V-type asteroids is significantly larger than that of C-type or S-types (Helfenstein, P., Veverka, J. [1989]. Physical characterization of asteroid surfaces from photometric analysis. In: Binzel, R., Gehrels, T., Matthews, M.S. (Eds.), Asteroids II. University of Arizona Press, Tucson, pp. 557–593). This result is consistent with radar studies showing that igneous rocky asteroids – the E and V types – exhibit the largest surface roughness (Benner, L. et al. [2008]. Icarus 198, 294–304). The effects of what appears to be space weathering can be largely explained by phase reddening in our collection of V-type NEOs, but our finding that smaller vestoids, which have shorter lifetimes, are more similar to Vesta suggests that some type of alteration of the surface through time occurs. Our observations confirm that the south polar region of Vesta has a more diogenitic composition than its equatorial regions. The south pole, which is dominated by a large impact feature, thus may offer a view into the interior of Vesta. We derive a visible phase integral of 0.44 ± 0.02 and a corresponding Bond albedo of 0.15 ± 0.03 from our composite V-type asteroid solar phase curve

Trends in Industrial Concentration in Japan, 1983-92

Based on weighted and unweighted averages of concentration ratios and the Herfindahl index for 436 sectors, the number of concentrated industries, and time trends, the structure of the Japanese economy proves highly oligopolistic over the 1983-92 period. Regression results show that concentration is related to growth, market size, scale economies, and the degree of 'openness' of the Japanese market. Moreover, increased concentration does not necessarily imply an import-bias. Japanese industries with higher concentration levels are likely to import more than less concentrated industries.