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The Maillard reaction, a chemical reaction between amino acids and sugars, is exploited to produce flavorful food ubiquitously, from the baking industry to our everyday lives. However, the Maillard reaction also occurs in all cells, from prokaryotes to eukaryotes, forming advanced glycation end-products (AGEs). AGEs are a heterogeneous group of compounds resulting from the irreversible reaction between biomolecules and α-dicarbonyls (α-DCs), including methylglyoxal (MGO), an unavoidable byproduct of anaerobic glycolysis and lipid peroxidation. We previously demonstrated that Caenorhabditis elegans mutants lacking the glod-4 glyoxalase enzyme displayed enhanced accumulation of α-DCs, reduced lifespan, increased neuronal damage, and touch hypersensitivity. Here, we demonstrate that glod-4 mutation increased food intake and identify that MGO-derived hydroimidazolone, MG-H1, is a mediator of the observed increase in food intake. RNAseq analysis in glod-4 knockdown worms identified upregulation of several neurotransmitters and feeding genes. Suppressor screening of the overfeeding phenotype identified the tdc-1-tyramine-tyra-2/ser-2 signaling as an essential pathway mediating AGE (MG-H1)-induced feeding in glod-4 mutants. We also identified the elt-3 GATA transcription factor as an essential upstream regulator for increased feeding upon accumulation of AGEs by partially controlling the expression of tdc-1 gene. Furthermore, the lack of either tdc-1 or tyra-2/ser-2 receptors suppresses the reduced lifespan and rescues neuronal damage observed in glod-4 mutants. Thus, in C. elegans, we identified an elt-3 regulated tyramine-dependent pathway mediating the toxic effects of MG-H1 AGE. Understanding this signaling pathway may help understand hedonistic overfeeding behavior observed due to modern AGE-rich diets.

Many vital processes in the eye are under circadian regulation, and circadian dysfunction has emerged as a potential driver of eye aging. Dietary restriction is one of the most robust lifespan-extending therapies and amplifies circadian rhythms with age. Herein, we demonstrate that dietary restriction extends lifespan in Drosophila melanogaster by promoting circadian homeostatic processes that protect the visual system from age- and light-associated damage. Altering the positive limb core molecular clock transcription factor, CLOCK, or CLOCK-output genes, accelerates visual senescence, induces a systemic immune response, and shortens lifespan. Flies subjected to dietary restriction are protected from the lifespan-shortening effects of photoreceptor activation. Inversely, photoreceptor inactivation, achieved via mutating rhodopsin or housing flies in constant darkness, primarily extends the lifespan of flies reared on a high-nutrient diet. Our findings establish the eye as a diet-sensitive modulator of lifespan and indicates that vision is an antagonistically pleiotropic process that contributes to organismal aging.

With temperatures expected to rise across the southern Rocky Mountains, the ability of native fishes to tolerate stream warming has become a critical concern for those tasked with preserving coldwater species. We used common garden experiments to evaluate the thermal tolerance of cutthroat trout (Oncorhynchus clarkii) fry from five populations important to managers representing three sub-species. Critical thermal maxima (CTMs) were evaluated through traditional exposure trials, while optimal growth and ultimate upper incipient lethal temperatures (UUILTs) were examined over the course of 21-day trials at six static temperature treatments. Whereas CTMs differed among populations (mean = 27.91[degrees]C, SD = 0.35[degrees]C), UUILTs did not (mean = 24.40[degrees]C, SD = 0.04[degrees]C). Comparison of cubic temperature-growth functions to the traditional quadratic functions showed that adding a third-order term for temperature can improve model fit, and revealed substantial differences in optimal growth temperatures (15.4-18.3[degrees]C). Knowledge of these thermal tolerance thresholds will help to predict the consequences of a warming climate, identify suitable habitats for repatriation, and inform water quality temperature standards established to protect these fish into the future. Key words: cutthroat trout, adaptive capacity, thermal tolerance, critical thermal maxima Au vu de la hausse prevue des temperatures dans le sud des montagnes Rocheuses, la capacite des poissons indigenes de tolerer le rechauffement des cours d'eau est devenue particulierement preoccupante pour les instances chargees de la preservation d'especes d'eau froide. Nous utilisons des experiences de jardin commun pour evaluer la tolerance a la temperature d'alevins de truite fardee (Oncorhynchus clarkii) de cinq populations d'importance pour les gestionnaires, qui representent trois sous-especes. Les temperatures maximums critiques (TMC) sont evaluees par des essais traditionnels d'exposition, alors que la croissance optimale et les temperatures letales superieures sont examinees au cours d'essais de 21 jours pour six traitements de temperature statique. Si les TMC different d'une population a l'autre (moyenne = 27,91[degrees]C, ET = 0,35[degrees]C), ce n'est pas le cas pour la temperature letale superieure (moyenne = 24,40[degrees]C, ET = 0,04[degrees]C). La comparaison de fonctions temperature-croissance cubiques aux fonctions quadratiques traditionnelles montre que l'ajout d'un terme de troisieme ordre pour la temperature peut ameliorer le calage des modeles et revele des differences considerables des temperatures de croissance optimales (15,418,3 [degrees]C). La connaissance de ces seuils de tolerance a la temperature aidera a predire les consequences du rechauffement climatique, a cerner des habitats se pretant au rapatriement et a eclairer la definition de normes de qualite de l'eau en matiere de temperature visant a proteger ces poissons a l'avenir. [Traduit par la Redaction] Mots-cles : truite fardee, capacite d'adaptation, tolerance a la temperature, temperature maximum critique, Introduction A radically altered future climate (Cook et al. 2004; Hansen etal. 2012; Hansen etal. 2013) is predicted to have dire consequences for the conservation of native coldwater fishes (Rahel [...]

Abstract: Because some salmonids show decreased swimming performance ([U.sub.crit]) during their parr-smolt transformation, we tested the hypothesis that juvenile anadromous green sturgeon (Acipenser medirostris) decrease [U.sub.crit] during their analogous ontogenetic [...]