Pena, I. | Search bioRxiv

bioRxiv2024

Identification of novel Bromodomain inhibitors of Trypanosoma cruzi Bromodomain Factor 2 (TcBDF2) using a fluorescence polarization-base high-throughput assay

Bromodomains are structural folds present in all eukaryotic cells that bind to other proteins recognizing acetylated lysines. Most proteins with bromodomains are part of nuclear complexes that interact with acetylated histone residues and participate in regulating DNA replication, transcription, and repair through chromatin structure remodeling. Bromodomain inhibitors are small molecules that bind to the hydrophobic pocket of bromodomains, interfering with the interaction with acetylated histones. Using a fluorescent probe, we have developed an assay to select inhibitors of the bromodomain factor 2 of Trypanosoma cruzi (TcBDF2) using fluorescence polarization. Initially, a library of 28,251 compounds was screened in an endpoint assay. The top 350 ranked compounds were further analyzed in a dose-response assay. From this analysis, 7 compounds were obtained that had not been previously characterized as bromodomain inhibitors. Although these compounds did not exhibit significative trypanocidal activity, all showed bona fide interaction with TcBDF2 with dissociation constants between 1 and 3 M validating these assays to search for bromodomain inhibitors.

microbiology↗

bioRxiv2022

Huddling nest use are the optimal strategies for heat conservation in a social marsupial: lessons from biophysical models.

Endothermy, understood as the maintenance of continuous and high body temperatures (TB) due to the combination of metabolic heat production and an insulative cover, is severely challenged in small endotherms of cold environments. As a response, social clustering, and nest use (collectively, "communal nesting") are common strategies for heat conservation in small mammals and birds. To quantify the actual amount of energy that is saved by communal nesting, we studied the social marsupial Dromiciops gliroides (monito del monte), a relict marsupial species from the cold forests of southern South America. It is hypothesized that sociability in this marsupial was driven by the cold, for which we calculated the energetic benefits that communal nesting confers. Using biophysical models and experimental coolings, we simulated heat exchanges experienced by grouped or solitary individuals, and also individuals within nests, collected from the field. Assuming a model of passive cooling, we calculated the net energy cost of euthermic maintenance (Ecost: the total energy needed to maintain euthermia). We adjusted 50 cooling curves, to exponential decay models, and found in all cases that the strategy minimizing heat loss is to be clustered within a nest, for which the Ecost was the minimum. This was significantly lower than the clustered condition, outside the nest, a reduction that represents almost half of energy consumption per day in a resting, thermoneutral condition for this marsupial. Overall, our results suggest that the strategy that significantly maximized heat conservation, compared with alternative strategies, was communal nesting. These findings support the idea that, in this social mammal, sociality is driven by bioenergetic benefits.

physiology↗