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
Silver nanoparticles (nano-Ag) are potent and broad-spectrum antimicrobial agents. In this study, spherical nano-Ag (average diameter = 9.3 nm) particles were synthesized using a borohydride reduction method and the mode of their antibacterial action against E. coli was investigated by proteomic approaches (2-DE and MS identification), conducted in parallel to analyses involving solutions of Ag(+) ions. The proteomic data revealed that a short exposure of E. coli cells to antibacterial concentrations of nano-Ag resulted in an accumulation of envelope protein precursors, indicative of the dissipation of proton motive force. Consistent with these proteomic findings, nano-Ag were shown to destabilize the outer membrane, collapse the plasma membrane potential and deplete the levels of intracellular ATP. The mode of action of nano-Ag was also found to be similar to that of Ag(+) ions (e.g., Dibrov, P. et al, Antimicrob. Agents Chemother. 2002, 46, 2668-2670); however, the effective concentrations of nano-Ag and Ag(+) ions were at nanomolar and micromolar levels, respectively. Nano-Ag appear to be an efficient physicochemical system conferring antimicrobial silver activities.
The synthesis and structural, photophysical, electrochemical, and electroluminescent properties of a class of platinum(II) complexes bearing sigma-alkynyl ancillary ligands, namely [(C/N/N)Pt(C[triple bond]C]nR] [H(C/N/N) = 6-aryl-2,2'-bipyridine; n = 1-4; R = aryl, alkyl, or trimethylsilyl], have been studied. Substituents with different steric and electronic properties were introduced into the tridentate cyclometalating and arylacetylide ligands, and the pi-conjugation length of the oligoynyl moiety was homologously extended from ethynyl to octatetraynyl. The X-ray crystal structures of several derivatives confirm the Pt-(CC) ligation and reveal various intermolecular interactions, such as pi-pi, Pt...Pt, and C-H...F-C. The complexes display good thermal stability and intense phosphorescence in fluid and glassy solutions with high quantum yields and microsecond lifetimes. Their emission energies are sensitive to solvent polarity, the electronic affinities of the substituents on both the cyclometalating and arylacetylide groups, and the length of the oligoynyl ligand. By choosing appropriate cyclometalating and sigma-alkynyl ligands, the emission color of this class of platinum(II) complexes can be tuned from green-yellow to saturated red. In addition to (3)MLCT [Pt(5d) --> pi*(C/N/N)] and (3)IL(C/N/N), intriguing (3)IL(alkynyl) excited states localized on -(C[triple bond]C)(4)- and -(C[triple bond]Cpyrenyl-1) moieties that afford narrow-bandwidth emissions have been observed. Selected Pt(II) complexes were doped into the emissive region of multilayer, vapor-deposited organic light-emitting diodes. The tunable electrophosphorescence energy resembles that recorded in fluid solutions for these emitters, and the devices exhibit high luminance and efficiencies (up to 4.2 cd A(-1)).
Gold complexes have recently gained increasing attention in the design of new metal-based anticancer therapeutics. Gold(III) complexes are generally reactive/unstable under physiological conditions via intracellular redox reactions, and the intracellular Au(III) to Au(I) reduction reaction has recently been "traced" by the introduction of appropriate fluorescent ligands. Similar to most Au(I) complexes, Au(III) complexes can inhibit the activities of thiol-containing enzymes, including thioredoxin reductase, via ligand exchange reactions to form Au-S(Se) bonds. Nonetheless, there are examples of physiologically stable Au(III) and Au(I) complexes, such as [Au(TPP)]Cl (H2TPP = 5,10,15,20-tetraphenylporphyrin) and [Au(dppe)2]Cl (dppe = 1,2-bis(diphenylphosphanyl)ethane), which are known to display highly potent in vitro and in vivo anticancer activities. In this review, we summarize our current understanding of anticancer gold complexes, including their mechanisms of action and the approaches adopted to improve their anticancer efficiency. Some recent examples of gold anticancer chemotherapeutics are highlighted.
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