Search for: All records

Abstract Serial block face scanning electron microscopy (SBF‐SEM), also referred to as serial block‐face electron microscopy, is an advanced ultrastructural imaging technique that enables three‐dimensional visualization that provides largerx‐ andy‐axis ranges than other volumetric EM techniques. While SEM is first introduced in the 1930s, SBF‐SEM is developed as a novel method to resolve the 3D architecture of neuronal networks across large volumes with nanometer resolution by Denk and Horstmann in 2004. Here, the authors provide an accessible overview of the advantages and challenges associated with SBF‐SEM. Beyond this, the applications of SBF‐SEM in biochemical domains as well as potential future clinical applications are briefly reviewed. Finally, the alternative forms of artificial intelligence‐based segmentation which may contribute to devising a feasible workflow involving SBF‐SEM, are also considered. 

Abstract Despite an increase in programming to promote persons excluded by their ethnicity or race (PEER) scholars, minorities remain underrepresented in many STEM programs. The academic pipeline is largely leaky for underrepresented minority (URM) scholars due to a lack of effective mentorship. Many URM students experience microaggressions and discrimination from their mentors due to a lack of quality mentorship training. In this workshop, we provide a framework to show trainees what effective mentoring looks like. Mentees, especially URM trainees, can flourish in effective mentoring environments where they feel welcomed and can comfortably develop new ideas without feeling threatened by external factors. Effective mentoring environments provide motivational support, empathy, cultural competency, and training. This workshop explains facets of effective mentoring to students, as well as highlights to URM trainees why mentors can serve as valuable resources. 

Abstract Despite efforts to increase diversity, a glaring underrepresentation of minorities (URM) persists in the fields of science, technology, engineering, and mathematics (STEM). Graduate school can be a stressful step in the STEM pipeline, especially for students previously unaware of the structure and challenges of postgraduate education. To promote successful minority participation in STEM and prepare prospective students for the impending challenges of applying for and attending graduate school, we developed a workshop based on the mentoring and fostering of a champion-oriented mindset entitled, “The Trials and Tribulations of Graduate School: How Do You Make an Impact?.” Students from the HBCU Winston-Salem State University attended the workshop, and a pre/post—a 10-point Likert scale-based survey was administered. The questions used in this seminar were newly designed by the authors as program evaluations. The results suggest that the workshop was well-received by the students and provided information that they considered helpful to help navigate the graduate school process. 

Abstract 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 The success of mentoring derives from active and respectful listening and the willingness to learn and accept opportunities for personal growth. This shapes every trainee and their destined path in science, technology, engineering, and mathematics (STEM). The act of cultivating rapport, asking, and pondering meaningful questions, and receiving constructive feedback are critical to support a productive mentoring relationship. Successful mentoring in STEM can be established and allow mentees, especially underrepresented minorities (URMs), to flourish in an environment where they feel welcomed and supported. However, mentees from underrepresented groups often experience inadequate mentoring due to a mentor's lack of awareness, poor trainings themselves, or lack of understanding of the mentee’s hardships. It is important for mentors and mentees to work together to promote diversity, equity, and inclusion (DEI) in STEM education through creativity, authenticity, and networking. We analyzed data obtained from students who attended a recent workshop that are interested in going to graduate school. Our results show that despite low initial expectations for the workshop, many students were satisfied in the knowledge they gleaned. The future and role of diversity in STEM within these underrepresented groups lies in community support and an important role that they can play in the lives of others through DEI initiatives and throughout their careers all of which involves positive mentoring. 

Abstract During aging, muscle gradually undergoes sarcopenia, the loss of function associated with loss of mass, strength, endurance, and oxidative capacity. However, the 3D structural alterations of mitochondria associated with aging in skeletal muscle and cardiac tissues are not well described. Although mitochondrial aging is associated with decreased mitochondrial capacity, the genes responsible for the morphological changes in mitochondria during aging are poorly characterized. We measured changes in mitochondrial morphology in aged murine gastrocnemius, soleus, and cardiac tissues using serial block‐face scanning electron microscopy and 3D reconstructions. We also used reverse transcriptase‐quantitative PCR, transmission electron microscopy quantification, Seahorse analysis, and metabolomics and lipidomics to measure changes in mitochondrial morphology and function after loss of mitochondria contact site and cristae organizing system (MICOS) complex genes,Chchd3,Chchd6, andMitofilin. We identified significant changes in mitochondrial size in aged murine gastrocnemius, soleus, and cardiac tissues. We found that both age‐related loss of the MICOS complex and knockouts of MICOS genes in mice altered mitochondrial morphology. Given the critical role of mitochondria in maintaining cellular metabolism, we characterized the metabolomes and lipidomes of young and aged mouse tissues, which showed profound alterations consistent with changes in membrane integrity, supporting our observations of age‐related changes in muscle tissues. We found a relationship between changes in the MICOS complex and aging. Thus, it is important to understand the mechanisms that underlie the tissue‐dependent 3D mitochondrial phenotypic changes that occur in aging and the evolutionary conservation of these mechanisms betweenDrosophilaand mammals. 

Abstract Mitochondria respond to metabolic demands of the cell and to incremental damage, in part, through dynamic structural changes that include fission (fragmentation), fusion (merging of distinct mitochondria), autophagic degradation (mitophagy), and biogenic interactions with the endoplasmic reticulum (ER). High resolution study of mitochondrial structural and functional relationships requires rapid preservation of specimens to reduce technical artifacts coupled with quantitative assessment of mitochondrial architecture. A practical approach for assessing mitochondrial fine structure using two dimensional and three dimensional high‐resolution electron microscopy is presented, and a systematic approach to measure mitochondrial architecture, including volume, length, hyperbranching, cristae morphology, and the number and extent of interaction with the ER is described. These methods are used to assess mitochondrial architecture in cells and tissue with high energy demand, including skeletal muscle cells, mouse brain tissue, andDrosophilamuscles. The accuracy of assessment is validated in cells and tissue with deletion of genes involved in mitochondrial dynamics.