| 1. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 2. |
- Sierks, H., et al.
(författare)
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Images of Asteroid 21 Lutetia : A Remnant Planetesimal from the Early Solar System
- 2011
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 334:6055, s. 487-490
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Tidskriftsartikel (refereegranskat)abstract
- Images obtained by the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) cameras onboard the Rosetta spacecraft reveal that asteroid 21 Lutetia has a complex geology and one of the highest asteroid densities measured so far, 3.4 +/- 0.3 grams per cubic centimeter. The north pole region is covered by a thick layer of regolith, which is seen to flow in major landslides associated with albedo variation. Its geologically complex surface, ancient surface age, and high density suggest that Lutetia is most likely a primordial planetesimal. This contrasts with smaller asteroids visited by previous spacecraft, which are probably shattered bodies, fragments of larger parents, or reaccumulated rubble piles.
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| 3. |
- Keller, H. U., et al.
(författare)
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E-Type Asteroid (2867) Steins as Imaged by OSIRIS on Board Rosetta
- 2010
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 327:5962, s. 190-193
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Tidskriftsartikel (refereegranskat)abstract
- The European Space Agency's Rosetta mission encountered the main-belt asteroid (2867) Steins while on its way to rendezvous with comet 67P/Churyumov-Gerasimenko. Images taken with the OSIRIS (optical, spectroscopic, and infrared remote imaging system) cameras on board Rosetta show that Steins is an oblate body with an effective spherical diameter of 5.3 kilometers. Its surface does not show color variations. The morphology of Steins is dominated by linear faults and a large 2.1-kilometer-diameter crater near its south pole. Crater counts reveal a distinct lack of small craters. Steins is not solid rock but a rubble pile and has a conical appearance that is probably the result of reshaping due to Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) spin-up. The OSIRIS images constitute direct evidence for the YORP effect on a main-belt asteroid.
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| 4. |
- Gulkis, S., et al.
(författare)
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Millimeter and submillimeter measurements of asteroid (2867) Steins during the Rosetta fly-by
- 2010
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Ingår i: Planetary and Space Science. - : Elsevier BV. - 0032-0633 .- 1873-5088. ; 58:9, s. 1077-1087
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Tidskriftsartikel (refereegranskat)abstract
- The European Space Agency Rosetta Spacecraft passed within 803 km of the main belt asteroid (2867) Steins on 5 September 2008. The Rosetta Spacecraft carries a number of scientific instruments including a millimeter and submillimeter radiometer and spectrometer. The instrument, named MIRO (Microwave Instrument for the Rosetta Orbiter), consists of a 30-cm diameter, offset parabolic reflector telescope followed by two heterodyne receivers. Center-band operating frequencies of the receivers are near 190 GHz (1.6 mm) and 562 GHz (0.53 mm). Broadband continuum channels are implemented in both frequency bands for the measurement of near surface temperatures and temperature gradients. A 4096 channel CTS (chirp transform spectrometer) having 180 MHz total bandwidth and similar to 44 kHz resolution is also connected to the submillimeter receiver. We present the continuum observations of asteroid (2867) Steins obtained during the fly-by with the MIRO instrument. Spectroscopic data were also collected during the fly-by using the MIRO spectrometer fixed-tuned to rotational lines of several molecules. Results of the spectroscopic investigation will be the topic of a separate publication. Comparative thermal models and radiative transfer calculations for Steins are presented. Emissivities of Steins were determined to be 0.6-0.7 and 0.85-0.9 at wavelengths of 0.53 and 1.6 mm, respectively. The thermal inertia of Steins was estimated to be in the range 450-850 J/(m(2) s(0.5) K). Assuming that the emissivity of Steins is determined by the Fresnel reflection coefficients of the surface material, the area-averaged dielectric constant of the surface material is in the range 4-20. These values are rock-like, and are unlike the powdered-regolith surface of the Moon.
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| 5. |
- Mottola, S., et al.
(författare)
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The rotation state of 67P/Churyumov-Gerasimenko from approach observations with the OSIRIS cameras on Rosetta
- 2014
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 569, s. L2-
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Tidskriftsartikel (refereegranskat)abstract
- Aims. Approach observations with the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) experiment onboard Rosetta are used to determine the rotation period, the direction of the spin axis, and the state of rotation of comet 67P's nucleus. Methods. Photometric time series of 67P have been acquired by OSIRIS since the post wake-up commissioning of the payload in March 2014. Fourier analysis and convex shape inversion methods have been applied to the Rosetta data as well to the available ground-based observations. Results. Evidence is found that the rotation rate of 67P has significantly changed near the time of its 2009 perihelion passage, probably due to sublimation-induced torque. We find that the sidereal rotation periods P-1 = 12.76129 +/- 0.00005 h and P2 = 12.4043 +/- 0.0007 h for the apparitions before and after the 2009 perihelion, respectively, provide the best fit to the observations. No signs of multiple periodicity are found in the light curves down to the noise level, which implies that the comet is presently in a simple rotation state around its axis of largest moment of inertia. We derive a prograde rotation model with spin vector J2000 ecliptic coordinates lambda = 65 degrees +/- 15 degrees, beta = + 59 degrees +/- 15 degrees, corresponding to equatorial coordinates RA = 22 degrees, Dec = +76 degrees. However, we find that the mirror solution, also prograde, at lambda = 275 degrees +/- 15 degrees, beta = + 50 degrees +/- 15 degrees (or RA = 274 degrees, Dec = +27 degrees), is also possible at the same confidence level, due to the intrinsic ambiguity of the photometric problem for observations performed close to the ecliptic plane.
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| 6. |
- Vincent, J. -B, et al.
(författare)
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Physical Properties of Craters on Asteroid (21) Lutetia
- 2011
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Ingår i: Lunar and Planetary Institute Science Conference Abstracts.
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Konferensbidrag (refereegranskat)abstract
- This abstract presents the physical properties of craters derived from the measurement of depth/diameter ratios on asteroid (21) Lutetia. We show how the d/D ratio varies in different regions and how it can be used to better understand the processes that affected the surface.
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| 7. |
- Åkerström, Tobias, et al.
(författare)
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Comprehensive Re-Sequencing of Adrenal Aldosterone Producing Lesions Reveal Three Somatic Mutations near the KCNJ5 Potassium Channel Selectivity Filter.
- 2012
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 7:7
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Tidskriftsartikel (refereegranskat)abstract
- Aldosterone producing lesions are a common cause of hypertension, but genetic alterations for tumorigenesis have been unclear. Recently, either of two recurrent somatic missense mutations (G151R or L168R) was found in the potassium channel KCNJ5 gene in aldosterone producing adenomas. These mutations alter the channel selectivity filter and result in Na(+) conductance and cell depolarization, stimulating aldosterone production and cell proliferation. Because a similar mutation occurs in a Mendelian form of primary aldosteronism, these mutations appear to be sufficient for cell proliferation and aldosterone production. The prevalence and spectrum of KCNJ5 mutations in different entities of adrenocortical lesions remain to be defined.
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