All Faculty Deposits

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https://hdl.handle.net/10919/70873

The "All Faculty Deposits" collection contains works deposited by faculty and appointed delegates from the Elements (EFARs) system. For help with Elements, see Frequently Asked Questions on the Provost's website. In general, items can only be deposited if the item is a scholarly article that is covered by Virginia Tech's open access policy, or the item is openly licensed or in the public domain, or the item is permitted to be posted online under the journal/publisher policy, or the depositor owns the copyright. See Right to Deposit on the VTechWorks Help page. If you have questions email us at vtechworks@vt.edu.

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The swimming defect caused by the absence of the transcriptional regulator LdtR in Sinorhizobium meliloti is restored by mutations in the motility genes motA and motS
Sobe, Richard C.; Scharf, Birgit E. (Wiley, 2024-05)
The flagellar motor is a powerful macromolecular machine used to propel bacteria through various environments. We determined that flagellar motility of the alpha-proteobacterium Sinorhizobium meliloti is nearly abolished in the absence of the transcriptional regulator LdtR, known to influence peptidoglycan remodeling and stress response. LdtR does not regulate motility gene transcription. Remarkably, the motility defects of the ΔldtR mutant can be restored by secondary mutations in the motility gene motA or a previously uncharacterized gene in the flagellar regulon, which we named motS. MotS is not essential for S. meliloti motility and may serve an accessory role in flagellar motor function. Structural modeling predicts that MotS comprised an N-terminal transmembrane segment, a long-disordered region, and a conserved β-sandwich domain. The C terminus of MotS is localized in the periplasm. Genetics based substitution of MotA with MotAG12S also restored the ΔldtR motility defect. The MotAG12S variant protein features a local polarity shift at the periphery of the MotAB stator units. We propose that MotS may be required for optimal alignment of stators in wild-type flagellar motors but becomes detrimental in cells with altered peptidoglycan. Similarly, the polarity shift in stator units composed of MotB/MotAG12S might stabilize its interaction with altered peptidoglycan.
Chemoreceptors in Sinorhizobium meliloti require minimal pentapeptide tethers to provide adaptational assistance
Agbekudzi, Alfred; Scharf, Birgit E. (Wiley, 2024-07)
Sensory adaptation in bacterial chemotaxis is mediated by posttranslational modifications of methyl-accepting chemotaxis proteins (MCPs). In Escherichia coli, the adaptation proteins CheR and CheB tether to a conserved C-terminal receptor pentapeptide. Here,we investigated the function of the pentapeptide motif (N/D)WE(E/N)F in Sinorhizobium meliloti chemotaxis. Isothermal titration calorimetry revealed stronger affinity of the pentapeptides to CheR and activated CheB relative to unmodified CheB. Strains with mutations of the conserved tryptophan in one or all four MCP pentapeptides resulted in a significant decrease or loss of chemotaxis to glycine betaine, lysine, and acetate, chemoattractants sensed by pentapeptide-bearing McpX and pentapeptide-lacking McpU and McpV, respectively. Importantly, we discovered that the pentapeptide mediates chemotaxis when fused to the C-terminus of pentapeptide-lacking chemoreceptors via a flexible linker. We propose that adaptational assistance and a threshold number of available sites enable the efficient docking of adaptation proteins to the chemosensory array. Altogether, these results demonstrate that S. meliloti effectively utilizes a pentapeptide-dependent adaptation system with a minimal number of tethering units to assist pentapeptide-lacking chemoreceptors and hypothesize that the higher abundance of CheR and CheB in S. meliloti compared to E. coli allows for ample recruitment of adaptation proteins to the chemosensory array.
Cryo-EM structure of flagellotropic bacteriophage Chi
Sonani, Ravi R.; Esteves, Nathaniel C.; Scharf, Birgit E.; Egelman, Edward H. (Cell Press, 2024-07-11)
The flagellotropic bacteriophage χ (Chi) infects bacteria via the flagellar filament. Despite years of study, its structural architecture remains partly characterized. Through cryo-EM, we unveil χ′s nearly complete structure, encompassing capsid, neck, tail, and tail tip. While the capsid and tail resemble phage YSD1, the neck and tail tip reveal new proteins and their arrangement. The neck shows a unique conformation of the tail tube protein, forming a socket-like structure for attachment to the neck. The tail tip comprises four proteins, including distal tail protein (DTP), two baseplate hub proteins (BH1P and BH2P), and tail tip assembly protein (TAP) exhibiting minimal organization compared to other siphophages. Deviating from the consensus in other siphophages, DTP in χ forms a trimeric assembly, reducing tail symmetry from 6-fold to 3-fold at the tip. These findings illuminate the previously unexplored structural organization of χ’s neck and tail tip.
Serratia marcescens ATCC 274 increases production of the red pigment prodigiosin in response to Chi phage infection
Esteves, Nathaniel C.; Scharf, Birgit E. (Nature Portfolio, 2024-07-31)
Serratia marcescens is an opportunistic human pathogen that produces a vibrant red pigment called prodigiosin. Prodigiosin has implications in virulence of S. marcescens and promising clinical applications. We discovered that addition of the virulent flagellotropic bacteriophage χ (Chi) to a culture of S. marcescens stimulates a greater than fivefold overproduction of prodigiosin. Active phage infection is required for the effect, as a χ-resistant strain lacking flagella does not respond to phage presence. Via a reporter fusion assay, we have determined that the addition of a χ-induced S. marcescens cell lysate to an uninfected culture causes a threefold increase in transcription of the pig operon, containing genes essential for pigment biosynthesis. Replacement of the pig promoter with a constitutive promoter abolished the pigmentation increase, indicating that regulatory elements present in the pig promoter likely mediate the phenomenon. We hypothesize that S. marcescens detects the threat of phage-mediated cell death and reacts by producing prodigiosin as a stress response. Our findings are of clinical significance for two main reasons: (i) elucidating complex phage-host interactions is crucial for development of therapeutic phage treatments, and (ii) overproduction of prodigiosin in response to phage could be exploited for its biosynthesis and use as a pharmaceutical.
The dual role of a novel Sinorhizobium meliloti chemotaxis protein CheT in signal termination and adaptation
Agbekudzi, Alfred; Arapov, Timofey D.; Stock, Ann M.; Scharf, Birgit E. (Wiley, 2024-10)
Sinorhizobium meliloti senses nutrients and compounds exuded from alfalfa host roots and coordinates an excitation, termination, and adaptation pathway during chemotaxis. We investigated the role of the novel S. meliloti chemotaxis protein CheT. While CheT and the Escherichia coli phosphatase CheZ share little sequence homology, CheT is predicted to possess an α-helix with a DXXXQ phosphatase motif. Phosphorylation assays demonstrated that CheT dephosphorylates the phosphate-sink response regulator, CheY1~P by enhancing its decay two-fold but does not affect the motor response regulator CheY2~P. Isothermal Titration Calorimetry (ITC) experiments revealed that CheT binds to a phosphomimic of CheY1~P with a KD of 2.9 μM, which is 25-fold stronger than its binding to CheY1. Dissimilar chemotaxis phenotypes of the ΔcheT mutant and cheT DXXXQ phosphatase mutants led to the hypothesis that CheT exerts additional function(s). A screen for potential binding partners of CheT revealed that it forms a complex with the methyltransferase CheR. ITC experiments confirmed CheT/CheR binding with a KD of 19 μM, and a SEC-MALS analysis determined a 1:1 and 2:1 CheT/CheR complex formation. Although they did not affect each other's enzymatic activity, CheT binding to CheY1~P and CheR may serve as a link between signal termination and sensory adaptation.
Micro-Programming: A Dynamic and Flexible Approach to Student Engagement
Feerrar, Julia; Hammer, Kelsey (2025-06-06)
Academic library outreach and engagement often works at the nexus of multiple challenges. Librarians must meet the needs and interests of patron communities, make the most of limited staff time and resources, and navigate competing priorities for time and attention across campus. Over the last several years, our team of teaching librarians at Virginia Tech has sought out multiple opportunities to rethink and restrategize some of our approaches to these challenges. One approach, which we refer to as “micro-programming,” combines active learning techniques from the classroom with the flexibility and direct-to-student delivery method of outreach work such as tabling or events. In this paper, we will identify the principles our team has developed in experimenting with micro-programming and factors to consider for implementing this practice at other institutions.
Report of the American Psychological Association’s Board of Scientific Affairs Task Force on Promotion, Tenure, and Retention of Faculty of Color in Psychology
Azmitia, Margarita; Martin, Michelle Y.; Blue, Shawn; Bookwala, Jamila; Johnson, Marcus Lee; Perez, Marisol; Pham, Andy; Shear, Paula (American Psychological Association, 2025-06-05)
Recruitment, promotion, tenure, and retention of faculty of color remain significant challenges in academia. Despite an increasingly diverse population, the representation of faculty of color in tenure-track and senior faculty positions remains disproportionately low. Structural barriers, including bias in hiring and faculty evaluations, misalignment between academic culture and cultural values, unequal distribution of service labor, and limited access to mentorship and leadership opportunities, continue to hinder the advancement of faculty of color across academic ranks. This report summary from the American Psychological Association’s “Task Force Report on Promotion, Tenure, and Retention of Faculty of Color in Psychology” examines these systemic issues. It provides actionable recommendations for institutions to foster an equitable academic environment. Key strategies include enhancing recruitment efforts, implementing transparent and equitable tenure and promotion policies, addressing bias in evaluation metrics, and strengthening mentorship and retention initiatives. Additionally, the report emphasizes the importance of recognizing nontraditional scholarship, ensuring fair distribution of service responsibilities, and supporting leadership development for faculty of color.
Season's Greeting Card design - 2024
Bengtson, Kelsey (2024-11-20)
Virginia Tech Press logo
Bengtson, Kelsey (2025-04-01)
Virginia Tech Press Logo
Virginia Tech Authors Recognition Event 2025
Bengtson, Kelsey (2025-04-10)
Resident Librarian Annual Report
Bengtson, Kelsey; Brown, Ann; Glenn, Eric; Silva, Roberto (2025-05-14)
Collaboration with Eric Glenn, Roberto Silva and Ann Brown. Designed by Kelsey Bengtson
Imagine Weekend Itinerary
Bengtson, Kelsey; Puckett, Elise; Brammer, Paul; Brown, Ann (2025-03-05)
Collaboration with Elise, Ann and Paul for the design of the Imagine Weekend itinerary.
University Libraries Open Access Report 2022-2023.
Bengtson, Kelsey; Brown, Ann; Walz, Anita (2024-08-06)
Written by Anita Walz and Ann Brown. Designed by Kelsey Bengtson
University Libraries_FY24_Executive Report
Resident Librarian Conference graphic 2024
Bengtson, Kelsey; Glenn, Eric (2024-07-30)
Collaboration with Eric Glenn, team and multiple Universities for the Resident Librarian conference graphic.
Cheesy Nights Stickers - Collaboration with student workers
Bengtson, Kelsey; Slowinski, Milana; Wedling, Morgan (2025-04-30)
Return of diversity: Wetland plant community recovery following purple loosestrife biocontrol
Endriss, Stacy B.; Nuzzo, Victoria; Blossey, Bernd (2025-06-07)
Spread of non-native species can be important drivers of biodiversity declines, leading to precautionary management based on assumptions that (1) non-native biota have negative impacts and are “guilty” of causing harm and (2) reducing a non-native species' abundance will reduce these negative impacts, in turn, benefiting native species. However, we frequently lack data to gauge both negative impacts of non-native species and success or failure of chosen management interventions to benefit native species. Addressing these knowledge gaps is critical to improving management outcomes for native species while maintaining public trust to sustain funding of management activities. Here, we investigated the response of Lythrum salicaria (purple loosestrife) and associated plant communities to implementation of biological control in more than 10 wetland sites in New York State for up to 28 years. Introduced to North America from Europe in the 1800s, L. salicaria is a prime example of a non-native species with a continent-wide distribution that could not be suppressed by mechanical and chemical treatments. In the 1980s, waterfowl biologists, wetland managers, and conservationists alike worried about the loss of diverse wetland plant communities associated with the rapid expansion of L. salicaria. In response, after careful assessments of safety, and potential costs and benefits, four highly host-specific insect herbivores were released in North America in the early 1990s to reduce L. salicaria abundance and its negative ecological impacts. In a companion paper, Blossey et al. documented reduced L. salicaria occupancy and stem densities following insect releases over time (i.e., biological success), irrespective of site-specific differences in starting plant communities or L. salicaria abundance. Here, we show that reduced abundance of L. salicaria leads to the ultimate goal of non-native plant management: increased cover, abundance, and diversity of species, often of native species (i.e., ecological success). We also conduct analyses to provide inference about which plant species are most sensitive to L. salicaria, including changes in L. salicaria stem density. Overall, we provide an important conservation success story: our findings emphasize that biocontrol of non-native plants can be effective and safe, allowing native species to recover as a dominant non-native species gradually declines.
Elements of Leadership: Considerations for "Citizenship"
Kaufman, Eric K. (2025-06-07)
Opening seminar for 2025 TYIL Fellowship Program, an an initiative of the Teens and Youths in Leadership (TYIL) in Nigeria.
Insights into the in-situ degradation and fragmentation of macroplastics in a low-order riverine system
Gray, Austin D.; Gore, Beija; Gaesser, Megan; Sequeira, Luisana Rodriguez; Thibodeau, Tessa; Montgomery, Allison; Purvis, Sam; Ouimet, Kathryn; Dura, Tina; Mayer, Kathleen (Oxford University Press, 2025-05)
Inland riverine systems are major conduits of microplastics to coastal environments. Plastic materials that pass through riverine systems are subjected to various degradation processes that facilitate their fragmentation into microplastics (MPs). Low-order streams, a critical yet understudied part of river networks, significantly influence the fate and transport of MPs. Here, we investigate the in situ degradation of common macroplastic polymers (e.g., low-density polyethylene, polyethylene terephthalate, and polystyrene) and their fragmentation into MPs in urban and forested streams. We deployed macroplastic items and a natural biodegradable polymer (cellulose) into a stream habitat for 52 weeks. We found that regardless of stream type (forested or urban), macroplastic polymers produced MPs in two weeks, with polystyrene having the highest fragmentation rate (8 particles/week). We explored several degradation indices (carboxyl index, hydroxyl index, and vinyl index), which revealed that photooxidation played a role in macroplastic degradation over time. Another driver of degradation was biofilm formation observed on the surface of all items, mainly composed of diatoms. Lastly, we found that field-aged macroplastics can leach plastic-derived dissolved organic. Our study narrows the knowledge gap regarding MP degradation and fragmentation in freshwater by providing real-time in situ data on the rate of polymer fragmentation in a low-order riverine system.
Pre-conference professional workshop on Evalpreneurship in Africa
This interactive full-day workshop facilitated by Nicolas Uwitonze (Rwandan, who is currently pursuing a Ph.D. at Virginia Tech with a focus on Evalpreneurship and KAI), aims to delve into the intricate intersection of evaluation, consulting, entrepreneurship, and equity in the African context amid the digital age. Participants, ranging from intermediate to advanced, will actively engage in discussions and collaborative activities, gaining a holistic understanding of Evalpreneurship as a socially constructed phenomenon. The agenda includes an introduction to Evalpreneurship, exploration of global and African case studies, distinguishing evaluation entrepreneurship from consultancy, and discussions on the impact of technology and emerging trends in African evaluation entrepreneurship. The workshop will also feature an interactive session, allowing participants to explore challenges and opportunities in African Evalpreneurship through small group discussions and participant-led scenarios. The session concludes with an open forum for questions, reflections, and insights. Learner outcomes include gaining insights into holistic Evalpreneurship, exploring real-world applications and equity considerations, distinguishing evaluation entrepreneurship from consultancy, understanding the impact of technology on African evaluation entrepreneurship, and navigating complexities in participatory approaches. No certificates of participation will be provided, and the ideal number of participants is set at 12, with a maximum of 40. Course materials will consist of handouts, case studies, and access to relevant online resources. The workshop will be conducted in English, with simultaneous translation into French/Kinyarwanda available upon request. Young and emerging evaluators are mostly invited, as well as intermediate to Advanced participants with an interest in evaluation, consulting and entrepreneurship. Justification/Relevance to the theme. The proposed workshop not only aligns with the conference theme but also directly addresses each of its objectives, by: 1) Advancing the Evaluation Agenda with Evidence-Based Policy Formulation: The workshop addresses the evolving landscape of evaluation practices by incorporating technology and innovation. It delves into the intricate intersection of evaluation, consulting, entrepreneurship, and equity in the African context, acknowledging the transformative impact of technology. The insights gained from the workshop empower participants to contribute meaningfully to evidence-based policy formulation, aligning with the conference's goal of strengthening Voluntary Organizations for Professional Evaluation (VOPEs) to collaborate with national governments. 2) Enhancing National Evaluation Capacities through Shared Experiences: The workshop provides a platform for participants to actively engage in discussions, collaborative activities, and real-world case studies. This interactive approach fosters a shared learning experience, enabling participants to explore challenges, opportunities, and lived experiences in the field of evaluation entrepreneurship. This aligns with the conference's objective of providing space for sharing experiences to enhance national evaluation capacities. 3) Showcasing Evaluative Evidence in Africa: By exploring real-world applications and equity considerations in Evalpreneurship, the workshop contributes to showcasing the diverse ways evaluative evidence can be leveraged for social impact. The insights gained from case studies and discussions offer tangible examples of how evaluation, entrepreneurship, and technology intersect in the African context, thereby contributing to the conference's goal of showcasing the use of evaluative evidence in Africa. 4) Development of Young and Emerging Evaluators: The workshop specifically targets young and emerging evaluators, providing them with practical knowledge and skills to navigate the evolving landscape of Evalpreneurship. By actively engaging this demographic, the workshop contributes directly to the conference's aim of developing young and emerging evaluators as agents of change. It empowers them to understand the complexities of the digital age and fosters their role as catalysts in the evaluation field.

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