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Understanding how metabolic reprogramming happens in cells will aid the progress in the treatment of a variety of metabolic disorders. Brown bears undergo seasonal shifts in insulin sensitivity, including reversible insulin resistance in hibernation. We performed RNA-sequencing on brown bear adipocytes and proteomics on serum to identify changes possibly responsible for reversible insulin resistance. We observed dramatic transcriptional changes, which depended on both the cell and serum season of origin. Despite large changes in adipocyte gene expression, only changes in eight circulating proteins were identified as related to the seasonal shifts in insulin sensitivity, including some that have not previously been associated with glucose homeostasis. The identified serum proteins may be sufficient for shifting hibernation adipocytes to an active-like state.
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http://dx.doi.org/10.1016/j.isci.2022.105084 | DOI Listing |
Zoolog Sci
August 2025
Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan,
Copy number variation (CNV) in gene loci in animals can be driven by adaption to the environment. The relationship between CNV in genes for amylase (), which hydrolyzes starch, and dietary adaptation has been well studied. Copy number (CN) of is higher in human populations with high-starch diets, compared with those with low-starch diets.
View Article and Find Full Text PDFJ Wildl Dis
September 2025
Division of Wildlife Conservation, Alaska Dept of Fish and Game, 1300 College Road, Fairbanks, Alaska 99701, USA.
This report describes highly pathogenic avian influenza virus (HPAI) H5N1 infections in carnivores in Alaska, US between 2022 and 2024, including a black bear (Ursus americanus), a brown bear (Ursus arctos), and the first known report of HPAI in an ermine (Mustela ermina). The two bears were cubs, and the ermine was a young adult. The black bear and ermine were euthanized after demonstrating neurologic signs, including circling, blindness, ataxia, or seizures.
View Article and Find Full Text PDFJAMA Netw Open
September 2025
Department of Child and Adolescent Psychiatry, NYU Grossman School of Medicine, New York, New York.
Importance: Studies suggest developmental concerns for infants born during the COVID-19 pandemic, but evidence on its impact on toddler behavioral and emotional well-being remains limited.
Objective: To assess whether birth timing relative to the COVID-19 pandemic is associated with toddler internalizing and externalizing problems.
Design, Setting, And Participants: This retrospective cohort study utilized Environmental Influences on Child Health Outcomes (ECHO) cohort data collected between September 27, 2009, and July 21, 2023.
ISME J
September 2025
School of Life Science, Shandong University, Qingdao 266237, China.
The gut microbiota is a key regulator of host energy metabolism, but its role in seasonal adaptation and evolution of bears is still unclear. Although giant pandas are considered an extraordinary member of the Ursidae family due to their specialized herbivory and low metabolic rate, there is still controversy over whether the metabolic regulation mechanism of their gut microbiota is unique. This study analyzed the seasonal dynamics of gut microbiota in giant pandas (Ailuropoda melanoleuca), Asian black bears (Ursus thibetanus), brown bears (Ursus arctos), and polar bears (Ursus maritimus), and combined with fecal microbiota transplantation (FMT) experiments, revealed the following findings.
View Article and Find Full Text PDFPhysiol Rep
September 2025
Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
In humans, hypothermia prolongs ventricular repolarization and associates with sustained ventricular tachyarrhythmias. In bears, body temperature drops during hibernation similar to moderate human hypothermia, yet they rarely face fatal outcomes during the winter. This suggests protective adaptations in bear electrophysiology.
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