Biology subjects

Aaronson, B.

Publications and source records attributed to Aaronson, B..

2 recordsLinked to original sources

bioRxiv2025

In C57Bl6 Mice, Obesity and Subsequent Weight Loss Negatively Affected the Skeleton and Shifted the Cortical Bone Metabolome

Obesity and calorie restriction each negatively affect skeletal health. Despite the negative effects of weight loss on the skeleton, obese patients are advised to lose weight via calorie restriction. Additionally, obesity and weight loss individually alter both whole-body and local metabolism. Little is known about bone quality and changes to the cortical metabolome following calorie restriction in obese preclinical models. We hypothesized that caloric restriction would worsen bone quality in obese mice by shifting the cortical bone metabolome. To induce obesity, 8-week-old male and female C57BL6/J mice received 60% high-fat diet for 12 weeks. From 20 to 30 weeks of age, mice either remained obese or lost weight through 30% caloric restriction. Control animals received a 10% low-fat diet. Bodyweight and fat mass were increased by obesity and decreased with calorie restriction. Similarly, glucose and insulin tolerance were worsened with obesity but improved by weight loss. Compared to obesity, calorie restriction elicited more bone loss in both cortical and trabecular compartments. Weight loss also reduced bone formation. Both obesity and subsequent calorie restriction altered the cortical bone metabolome in a sex-dependent manner. Metabolic pathways altered with diet generally mapped to amino acid or fatty acid metabolism. In males, weight loss was associated with a downregulation of pathways related to tryptophan, tyrosine, ubiquinone, and fatty acids. In females, calorie restriction downregulated taurine and hypotaurine metabolism but upregulated pyrimidine metabolism, nicotinate and nicotinamide metabolism, and pantothenate and CoA biosynthesis. Our findings highlight the negative effects of obesity and subsequent caloric restriction on the skeleton. Despite improvements in components of systemic metabolism, caloric restriction in obese preclinical models did not restore bone morphology or the cortical metabolome to control conditions.

cell biology↗

bioRxiv2023

Ontogeny and social context regulate the circadian activity patterns of Lake Malawi cichlids

Activity patterns tend to be highly stereotyped and critical for executing many different behaviors including foraging, social interactions and predator avoidance. Differences in the circadian timing of locomotor activity and rest periods can facilitate habitat partitioning and the exploitation of novel niches. As a consequence, closely related species often display highly divergent activity patterns, raising the possibility that a shift from diurnal to nocturnal behavior, or vice versa, can occur rapidly. In Africas Lake Malawi alone, there are over 500 species of cichlids, which inhabit diverse environments and exhibit extensive phenotypic variation. We have previously identified a substantial range in activity patterns across adult Lake Malawi cichlid species, from strongly diurnal to strongly nocturnal. In many species, including fishes, ecological pressures differ dramatically across life-history stages, raising the possibility that activity patterns may change over ontogeny. To determine if rest-activity patterns change across life stages we compared the locomotor patterns of six Lake Malawi cichlid species. While total rest and activity did not change between early juvenile and adult stages, rest-activity patterns did, with juveniles displaying distinct activity rhythms that are more robust than adults. One distinct difference between juveniles and adults is the emergence of complex social behavior. To determine whether social context is required for activity rhythms, we next measured locomotor behavior in group housed adult fish. We found that when normal social interactions were allowed, locomotor activity patterns were restored, supporting the notion that social interactions promote circadian regulation of activity in adult fish. These findings reveal a previously unidentified link between developmental stage and social interactions in the circadian timing of cichlid activity.

evolutionary biology↗