Immunoblot-based assays for assessing autophagy in the turquoise killifish Nothobranchius furzeri.

Autophagy is an evolutionarily conserved biological process required for the turnover of the cytoplasm of eukaryotic cell. Beyond its catabolic nature, autophagy has a plethora of pro-survival functions, thus combatting hypoxia, nutrient shortage, and unfolded protein accumulation. Here, we introduce the naturally short-lived turquoise killifish Nothobranchius furzeri as an emerging model to study autophagic function in vivo, in response to environmental challenges. We show that starvation in killifish is sufficient to increase autophagic flux in the liver, thus enhancing the lipidation of microtubule-associated protein light chain 3 (LC3) and reducing the abundance of the autophagic substrate sequestosome-1 (SQSTM1). We describe an immunoblot-based comprehensive protocol to monitor fluctuations in autophagy in this model organism.

Physical models of infant mortality: implications for defects in biological systems.

Reliability engineering concerned with failure of technical inanimate systems usually uses the vocabulary and notions of human mortality, e.g., infant mortality vs. senescence mortality. Yet, few data are available to support such a parallel description. Here, we focus on early-stage (infant) mortality for two inanimate systems, incandescent light bulbs and soap films, and show the parallel description is clearly valid. Theoretical considerations of the thermo-electrical properties of electrical conductors allow us to link bulb failure to inherent mechanical defects. We then demonstrate the converse, that is, knowing the failure rate for an ensemble of light bulbs, it is possible to deduce the distribution of defects in wire thickness in the ensemble. Using measurements of lifetimes for soap films, we show how this methodology links failure rate to geometry of the system; in the case presented, this is the length of the tube containing the films. In a similar manner, for a third example, the time-dependent death rate due to congenital aortic valve stenosis is related to the distribution of degrees of severity of this condition, as a function of time. The results not only validate clearly the parallel description noted above, but also point firmly to application of the methodology to humans, with the consequent ability to gain more insight into the role of abnormalities in infant mortality.

A Semi-Automatic Dispenser for Solid and Liquid Food in Aquatic Facilities.

We present a novel, low-footprint and low-cost semi-automatic system for delivering solid and liquid food to zebrafish, and more generally to aquatic animals raised in racks of tanks. It is composed of a portable main module equipped with a contactless reader that adjusts the quantity to deliver for each tank, and either a solid food module or a liquid food module. Solid food comprises virtually any kind of dry powder or grains below 2 mm in diameter, and, for liquid-mediated food, brine shrimps (Artemia salina) and rotifers (Rotifera) have been successfully tested. Real-world testing, feedback, and validation have been performed in a zebrafish facility for several months. In comparison with manual feeding this system mitigates the appearance of musculoskeletal disorders among regularly-feeding staff, and let operators observe the animals' behavior instead of being focused on quantities to deliver. We also tested the accuracy of both humans and our dispenser and found that the semi-automatic system is much more reliable, with respectively 7-fold and 84-fold drops in standard deviation for solid and liquid food.