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- 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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- Lin, Chang, et al.
(författare)
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Green aerator using periodically oscillatory flow generated inside a vertical dropping pool
- 2012
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Konferensbidrag (refereegranskat)abstract
- The flow conditions for generating periodically oscillatory flows and thus entraining a large amount of air bubbles into the water mass in a vertical dropping pool, which can be used potentially as a green aerator, were investigated experimentally. The approaching flows passing through upstream reach of a vertical dropping pool were studied under sub-critical condition. A wave gauge was used to measure the free surface fluctuations in the pool, and flow visualization technique was employed to reveal the flow structure of the dropping flows qualitatively. Under certain conditions, the falling flow over a vertical dropping pool forms a switching jet that oscillates up and down periodically and impinges on the bottom and the downstream corner of the pool alternately. The switching jet switches between an impinging jet (or napped flow) and a sliding jet (or skimming flow), causing it to oscillate periodically with a unique period and to entrain a large number of air bubbles into the switching jet, thus enhancing the dissolved oxygen quantity and turbulent mixing. The primary frequency of the periodic oscillation was determined by applying spectral analysis to the time history of wave-gauge measurements for the free surface elevation of the dropping flows. Variables influencing the fundamental oscillation frequency were carefully checked, and an empirical relation between a weighted Strouhal number and a grouped non-dimensional parameter was proposed to predict the primary frequency of the periodically oscillatory flow.
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