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The sorting and assembly machinery (SAM) Complex is responsible for assembling β‐barrel proteins in the mitochondrial membrane. Comprising three subunits, Sam35, Sam37, and Sam50, the SAM complex connects the inner and outer mitochondrial membranes by interacting with the mitochondrial contact site and cristae organizing system complex. Sam50, in particular, stabilizes the mitochondrial intermembrane space bridging (MIB) complex, which is crucial for protein transport, respiratory chain complex assembly, and regulation of cristae integrity. While the role of Sam50 in mitochondrial structure and metabolism in skeletal muscle remains unclear, this study aims to investigate its impact. Serial block‐face‐scanning electron microscopy and computer‐assisted 3D renderings were employed to compare mitochondrial structure and networking in Sam50‐deficient myotubes from mice and humans with wild‐type (WT) myotubes. Furthermore, autophagosome 3D structure was assessed in human myotubes. Mitochondrial metabolic phenotypes were assessed using Gas Chromatography‐Mass Spectrometry‐based metabolomics to explore differential changes in WT and Sam50‐deficient myotubes. The results revealed increased mitochondrial fragmentation and autophagosome formation in Sam50‐deficient myotubes compared to controls. Metabolomic analysis indicated elevated metabolism of propanoate and several amino acids, including ß‐Alanine, phenylalanine, and tyrosine, along with increased amino acid and fatty acid metabolism in Sam50‐deficient myotubes. Furthermore, impairment of oxidative capacity was observed upon Sam50 ablation in both murine and human myotubes, as measured with the XF24 Seahorse Analyzer. Collectively, these findings support the critical role of Sam50 in establishing and maintaining mitochondrial integrity, cristae structure, and mitochondrial metabolism. By elucidating the impact of Sam50‐deficiency, this study enhances our understanding of mitochondrial function in skeletal muscle. [ABSTRACT FROM AUTHOR]

Mitochondria are required for energy production and even give brown adipose tissue (BAT) its characteristic color due to their high iron content and abundance. The physiological function and bioenergetic capacity of mitochondria are connected to the structure, folding, and organization of its inner‐membrane cristae. During the aging process, mitochondrial dysfunction is observed, and the regulatory balance of mitochondrial dynamics is often disrupted, leading to increased mitochondrial fragmentation in aging cells. Therefore, it is hypothesized that significant morphological changes in BAT mitochondria and cristae will be present with aging. A quantitative 3D electron microscopy approach is developed to map cristae network organization in mouse BAT to test this hypothesis. Using this methodology, the 3D morphology of mitochondrial cristae is investigated in adult (3‐month) and aged (2‐year) murine BAT tissue via serial block face‐scanning electron microscopy (SBF‐SEM) and 3D reconstruction software for manual segmentation, analysis, and quantification. Upon investigation, an increase is found in mitochondrial volume, surface area, and complexity and decreased sphericity in aged BAT, alongside significant decreases in cristae volume, area, perimeter, and score. Overall, these data define the nature of the mitochondrial structure in murine BAT across aging. [ABSTRACT FROM AUTHOR]

Researchers remain divided over the cause of Bernie Sanders' strong appeal in recent Democratic primaries, alternately positing identity or ideology as decisive drivers of Sanders support. Using data from 2020 Nationscape, we conduct linear probability models that show how identity, ideology, and their interaction all explain Sanders support. Demographically, we find that Sanders voters are disproportionately young, Hispanic, and Independent. Sanders voters also differ significantly from other Democratic primary voters across several ideology variables, and are especially supportive of policies that were central to Sanders' campaign, such as providing government-run health insurance to all Americans. Finally, we demonstrate that age cohort, the most important predictor of Sanders support, has an effect that is highly dependent upon key ideology variables. Overall, those who did not vote for Sanders in the 2020 Democratic primary are quite demographically and ideologically distinct from those voters that "felt the Bern." [ABSTRACT FROM AUTHOR]

The cover image of the August 2024 issue of the Journal of Cellular Physiology is based on an article titled "Ablation of Sam50 is associated with fragmentation and alterations in metabolism in murine and human myotubes" by Bryanna Shao et al. The article explores the effects of Sam50 ablation on the fragmentation and metabolism of myotubes in mice and humans. The research involves a large group of authors from diverse backgrounds and is available for further exploration through the provided DOI link. [Extracted from the article]