| 1. |
- Klionsky, Daniel J., et al.
(författare)
-
Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
-
Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
-
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.
|
|
| 2. |
- Angus-Dunne, Sarah, et al.
(författare)
-
Synthesis and Crystal Structure of the Palladium(IV) Polyoxomolybdate, K0 75Na3 75[PdMo6O24H3 5]center dot 17H(2)O
- 2010
-
Ingår i: Zeitschrift für Anorganische und Allgemeines Chemie. - : Wiley. - 0044-2313 .- 1521-3749. ; 636:5, s. 727-734
-
Tidskriftsartikel (refereegranskat)abstract
- The first example of a heteropolyoxomolybdate containing palladium(IV) was isolated and characterized by X ray crystallography The palladium(IV) hexamolybdate, K0 75Na3 75[PdMo6O24H3 (5)] 17H(2)O, was isolated from an aqueous solution at pH 4 5 in the space group P (1) over bar a 10 790(2) b 12 244(3), c 14 086(3) angstrom, alpha 113 77(1), beta 90 41(1) gamma 107 86(1)degrees and the structure was determined using X ray diffraction methods refining to a residual of 0 0301 for 5334 reflections A formal [PdMo6O24H3](5-) subunit exhibits the basic Anderson structure with two [PdMo6O24H3](5-) cluster anions in the structure bridged by a hydrogen atom (formally an H+) situated on a center of symmetry to give a [Pd2Mo12O48H7](9-) dimeric anion The palladium(IV) atom occupies a slightly distorted octahedral environment with Pd-O distances ranging from 1 968 to 2 009 angstrom.
|
|
| 3. |
- Steen, Robert, 1978-
(författare)
-
Molecular Electronic Devices based on Ru(II) Thiophenyl Pyridine and Thienopyridine Architecture
- 2010
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- According to the famous axiom known as Moore’s Law the number of transistors that can be etched on a given piece of ultra-pure silicon, and therefore the computing power, will double every 18 to 24 months. However, around 2020 hardware manufacturers will have reached the physical limits of silicon. A proposed solution to this dilemma is molecular electronics. Within this field researchers are attempting to develop individual organic molecules and metal complexes that can act as molecular equivalents of electronic components such as wires, diodes, transistors and capacitors. In this work we have synthesized a number of new bi- and terdentate thiophenyl pyridine and pyridyl thienopyridine ligands and compared the electrochemical, structural and photophysical properties of their corresponding Ru(II) complexes with Ru(II) complexes of a variety of ligands based on 6-thiophen-2-yl-2,2'-bipyridine and 4-thiophen-2-yl-2,2'-bipyridine motifs. While the electrochemistry of the Ru(II) complexes were similar to that of unsubstituted [Ru(bpy)3]2+ and [Ru(tpy)2]2+, substantial differences in luminescence lifetimes were found. Our findings show that, due to steric interactions with the auxiliary bipyridyl ligands, luminescence is quenched in Ru(II) complexes that incorporate the 6-thiophen-2-yl-2,2'-bipyridine motif, while it was comparable with the luminescence of [Ru(bpy)3]2+ in the Ru(II) complexes of bidentate pyridyl thienopyridine ligands. The luminescence of the Ru(II) complexes based on the 4-thiophen-2-yl-2,2'-bipyridine motif was enhanced compared to [Ru(bpy)3]2+ which indicates that complexes of this category may be applicable for energy/electron-transfer systems. At the core of molecular electronics is the search for molecular ON/OFF switches. Based on the ability of the ligand 6-thiophen-2-yl-2,2'-bipyridine to switch reversibly between cyclometallated and non-cyclometallated modes when complexed with Ru(tpy) we have synthesized a number of complexes, among them a bis-cyclometallated switch based on the ligand 3,8-bis-(6-thiophen-2-yl-pyridin-2-yl)-[4,7]phenanthroline, and examined their electrochemical properties. Only very weak electronic coupling could be detected, suggesting only little, if any, interaction between the ruthenium cores.
|
|
| 4. |
- Sullivan, Mitchell A., et al.
(författare)
-
Molecular Structural Differences between Type-2-Diabetic and Healthy Glycogen
- 2011
-
Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 12:6, s. 1983-1986
-
Tidskriftsartikel (refereegranskat)abstract
- Glycogen is a highly branched glucose polymer functioning as a glucose buffer in animals. Multiple-detector size exclusion chromatography and fluorophore-assisted carbohydrate electrophoresis were used to examine the structure of undegraded native liver glycogen (both whole and enzymatically del;ranched) as a function of molecular size, isolated from the liver; of healthy and db/db mice (the latter a type 2 diabetic model). Both the fully branched and debranched levels of glycogen structure showed fundamental differences between glycogen from healthy and db/db mice. Healthy glycogen had a greater population of large particles, with more a particles (tightly linked assemblages of smaller,8 particles) than glycogen from db/db mice. These structural differences suggest a new understanding of type 2 diabetes.
|
|
| 5. |
- Sullivan, Mitchell A., et al.
(författare)
-
Nature of alpha and beta Particles in Glycogen Using Molecular Size Distributions
- 2010
-
Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 11:4, s. 1094-1100
-
Tidskriftsartikel (refereegranskat)abstract
- Glycogen is a randomly hyperbranched glucose polymer. Complex branched polymers have two structural levels: individual branches and the way these branches are linked. Liver glycogen has a third level: supramolecular clusters of beta particles which form larger clusters of alpha particles. Size distributions of native glycogen were characterized using size exclusion chromatography (SEC) to find the number and weight distributions and the size dependences of the number- and weight-average masses. These were fitted to two distinct randomly joined reference structures, constructed by random attachment of individual branches and as random aggregates of beta particles. The z-average size of the alpha particles in dimethylsulfoxide does not change significantly with high concentrations of LiBr, a solvent system that would disrupt hydrogen bonding. These data reveal that the beta particles are covalently bonded to form alpha particles through a hitherto unsuspected enzyme process, operative in the liver on particles above a certain size range.
|
|
