Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Cationic release behaviour of antimicrobial cellulose/silver nanocomposites

Silver nanoparticles (NPs) have received great attention, mainly due to their application as antimicrobial agents in diverse products, including textile- and paper-based materials. In this context, straightforward methodologies to monitor their cationic silver release capacity in diverse environments are required due to the rise of manufactured products containing silver NPs. Here, we describe the application of a potentiometric method based on a silver-selective electrode to monitor the kinetics of cationic release from cellulose/silver nanocomposites. We designed a set of experiments to apply this method to nanocomposites with several distinct types of cellulose matrices: vegetable, bacterial and nanofibrillated. The morphological features of the cellulose had a great influence on the distribution of silver NPs within the matrix as well as on the Ag+ release profiles. The cationic release profiles were interpreted based on common models, showing that, for the vegetal and bacterial cellulose nanocomposites, the kinetics is pseudo-first order, while for the nanofibrillated cellulose materials a model based on Fick's power law provided the best fit