Life Sciences Commons^™

Trophic Roles And Climate-Driven Vulnerability For Benthic Invertebrates At Artificial Reefs In The Northern Gulf Of Mexico, Amanda Kirkland

LSU New Orleans Theses and Dissertations

Artificial reefs are deployed to enhance marine habitats and fisheries, yet their role in supporting secondary production and their vulnerability to climate stressors remain understudied. This dissertation investigates the trophic ecology and climate sensitivity of benthic invertebrates at artificial reefs in the northern Gulf of Mexico. Chapter 1 assessed reef food webs using stable isotopes from fishes, invertebrates, and primary producers across six reefs and two seasons. Mixing models showed that most fishes rely on benthic reef carbon, while suspension feeders consume plankton and sediment microphytobenthos. Isotopic niche analysis revealed functional diversity and seasonal shifts in δ¹³C and δ³⁴S, though …

Consensus Statement On The Prevention And Management Of Complications Of Fully Ablative Laser Resurfacing Of The Face, Bianca Y Kang, Joel L Cohen, Roy Geronemus, Suzanne L Kilmer, Edward Victor Ross, Elizabeth L Tanzi, Jill S Waibel, Brian J F Wong, Murad Alam, Macrene Alexiades, Kenneth A Arndt, Mathew Avram, Ashish C Bhatia, Brian Stuart Biesman, Jason D Bloom, A Jay Burns, Henry H L Chan, Catherine M Digiorgio, Jeffrey S Dover, Sam Fathizadeh, Sara C Esteves, Michael H Gold, Gerald N Goldberg, Merete Haedersdal, Elika Hoss, Omar A Ibrahimi, H Ray Jalian, Kristen M Kelly, Woraphong Manuskiatti, Lisa A Marks, Girish S Munavalli, Jason N Pozner, Chris W Robb, Anthony M Rossi, Nazanin Saedi, Peter R Shumaker, Kelly Stankiewicz, Molly Wanner, Douglas C Wu, Adam J Wulkan, Arisa Ortiz

Faculty, Staff and Student Publications

Objectives: To achieve consensus among expert laser surgeons on standards for the prevention and management of adverse events from fully ablative laser resurfacing of the face.

Materials and methods: Delphi study with two rounds of ratings and revisions until consensus was achieved. The draft set of statements was developed by a steering committee based on expert clinical experience. This was followed by two rounds of rating and revisions completed by an expert panel, then a virtual consensus meeting. In both rounds, respondents rated the draft statements on a 9-point Likert scale (1 = strongly disagree; 9 = strongly agree) and …

Bayesian Counterfactual Machine Learning Individualizes Radiation Modality Selection To Mitigate Immunosuppression, Duo Yu, Michael J Kane, Yiqing Chen, Steven H Lin, Radhe Mohan, Brian P Hobbs

Faculty, Staff and Student Publications

Purpose: Lymphocytes play critical roles in cancer immunity and tumor surveillance. Radiation-induced lymphopenia (RIL) is a common side effect observed in patients with cancer undergoing chemoradiation therapy (CRT), leading to impaired immunity and worse clinical outcomes. Although proton beam therapy (PBT) has been suggested to reduce RIL risk compared with intensity-modulated radiation therapy (IMRT), this study used Bayesian counterfactual machine learning to identify distinct patient profiles and inform personalized radiation modality choice.

Methods: A novel Bayesian causal inferential technique is introduced and applied to a matched retrospective cohort of 510 patients with esophageal cancer undergoing CRT to identify patient profiles …

Development Of A Multi-Institutional Dataset To Validate A Novel Inflammatory Breast Cancer Diagnostic Score, Filipa Lynce, Samuel M Niman, Megumi Kai, Sean Ryan, Elizabeth Troll, Li Li, Kathy D Miller, Reshma Jagsi, Ginny Mason, Beth A Overmoyer, H T Carisa Le-Petross, Faina Nakhlis, Savitri Krishnamurthy, Beth T Harrison, Susie X Sun, Eren D Yeh, Jennifer R Bellon, Laura E Warren, Michael C Stauder, Meredith M Regan, Wendy A Woodward

Faculty, Staff and Student Publications

Background: Susan G. Komen, the Inflammatory Breast Cancer (IBC) Research Foundation, and the Milburn Foundation convened patient advocates, clinicians, and researchers to propose novel quantitative scoring rubrics for IBC diagnosis. In this study, we developed a multi-institutional clinical dataset to test and validate the proposed scoring system.

Methods: IBC (N = 988) and non-IBC (N = 332) cases were identified at 2 institutions with dedicated multidisciplinary IBC programs. The non-IBC cohort included consecutive cT4b and cT4c patients. Standard operating procedures (SOPs) were developed for all ambiguous findings and languages. Three different methods were used for the imputation of missing data, …

Dynamic Long-Term Prediction With Intermediate Event Information: A Flexible Model With Bivariate Time-Varying Coefficients, Yunyi Wang, Wen Li, Ruosha Li, Jing Ning

Faculty, Staff and Student Publications

The integration of time-to-intermediate event data and the evolving characteristics of patients to enhance long-term prediction has garnered significant interest, driven by the wealth of data generated from longitudinal cohorts. In this paper, we propose sequential/dynamic prediction rules by using regression models with time-varying coefficients. We introduce a class of dynamic models that not only incorporates intermediate event information but also leverages information across different landmark times. To address the challenge of right-censoring, we employ an inverse weighting technique in the estimation process. We establish the asymptotic properties of the estimated parameters and conduct extensive simulations to assess the finite …

De-Escalating Local Therapies Without Compromising Outcomes: Lessons From The Collision Trial, Jessica Albuquerque, Noreen S Siddiqi, Van K Morris, Hop Tran Cao, Iwan Paolucci, Bruno C Odisio

Faculty, Staff and Student Publications

No abstract provided.

Vascular Risk Factors And 1-Year Cognitive Change Among Individuals With Traumatic Brain Injury, Andrea L. C. Schneider, Katherine Hunzinger, Benjamin L. Brett, Danielle K Sandsmark, Sonia Jain, Xiaoying Sun, Raquel C. Gardner, Geoffrey T. Manley, Ramon Diaz-Arrastia, Lindsay D. Nelson, Patrick Belton, Shawn Eagle, Shankar Gopinath, Ramesh Grandhi, C. Dirk Keene, Vijay Krishnamoorthy, Christine Mac Donald, Michael Mccrea, Randall Merchant, Pratik Mukherjee, Laura B. Ngwenya, David Okonkwo, Claudia Robertson, David Schnyer, Sabrina R. Taylor, John K. Yue, Ross Zafonte

Department of Exercise Science Faculty Papers

IMPORTANCE: Traumatic brain injury (TBI) and vascular risk factors are associated with cognitive impairment, but it is unknown if individuals with vascular risk factors experience worse cognitive outcomes after TBI.

OBJECTIVE: To evaluate cognitive function among patients with TBI with vs without comorbid preinjury vascular risk factors.

DESIGN, SETTING, AND PARTICIPANTS: This prospective cohort study examined individuals with TBI enrolled in the Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) Study between February 26, 2014, and August 8, 2018, with a 1-year follow-up. Analyses were conducted February 26, 2024, to May 29, 2025.

EXPOSURES: Vascular risk factors (ie, hypertension, diabetes, …

Developing Targets To Control Multiple Pest Fly Species: Violet Polyester Targets Effectively Attract Tsetse (Diptera: Glossinidae), Stable Flies (Diptera: Muscidae), And House Flies (Diptera: Muscidae), Michael N. Okal, Sheillah J. Akinyi, Roger D. Santer

All Peer-Reviewed Publications

Tsetse (Glossina spp.), stable (Stomoxys spp.), and house flies (Musca domestica L.) impact humans and animals through bites and/or disease transmission. Tsetse are controlled using insecticide-coated fabric targets that are traditionally blue and/or black, but a violet polyester has now been engineered for greater attractiveness. Here, we investigate whether violet targets are also effective against stable and house flies. We sampled flies by electrocution at 1.0 (H) × 0.5 m (W) targets in Kenya, comparing catches at violet targets, and blue and black targets made from polyesters used in commercial traps and targets. Catches of female but not male Glossina …

Saliva & Circadian Rhythm In Medical Profiling For Early Disease Prevention, Joseph Lewis

Graduate Student Dissertations, Theses, Capstones, and Portfolios

Circadian rhythms affect almost every biological process from hormone secretion, gene expression, immune regulation, and metabolism. Studies show that disruption to these internal rhythms through irregular sleep, artificial sleep, and irregular sleep can significantly increase risk for chronic disease such as diabetes, cardiovascular disorders, neurodegeneration, and cancer. Saliva presents a viable alternative for capturing biomarkers found through blood or cerebrospinal fluid, offering substantial utility for diagnostic and chronobiological profiling. Saliva contains hormones such as cortisol and melatonin while containing inflammatory markers that fluctuate rhythmically throughout the day. Due to its ease of collection, saliva is well suited for longitudinal monitoring, …

Fluoride Toxicity And Benefit: An Integrated Review Of Mechanisms, Risks, And Public Health Impact, Sophia Chavarria

Graduate Student Dissertations, Theses, Capstones, and Portfolios

Fluoride has long been praised for its role in preventing dental caries, primarily through its effects on enamel remineralization and antibacterial effects. However, growing evidence from molecular and cellular studies suggests that excessive fluoride exposure, especially during tooth development, can lead to dental fluorosis and systemic toxicity. This paper examines the biological mechanisms underlying fluoride-induced dental fluorosis, with a focus on stress responses in ameloblasts, oxidative damage, impaired autophagy, and disrupted protein processing. It integrates data from in vitro, in vivo, and human studies to evaluate the cellular thresholds at which fluoride shifts from therapeutic to toxic. Systemic risks, including …

Effects Of Sediment Composition On Spartina Alterniflora And Juncus Roemerianus Productivity In Coastal Virginia: A Thin-Layer Sediment Placement Experiment, Caitlin Hemphill

Biological Sciences Theses & Dissertations

Climate change poses a major threat to the health of estuaries and their coastal wetland systems. The Chesapeake Bay’s coastal salt marshes are at high risk of inundation due to sea-level rise and land subsidence. Restoration techniques for maintaining coastal marsh resistance to sea-level rise are being developed and refined, with thin layer placement (TLP) emerging as a feasible solution in many areas of the United States. Despite TLPs use across the country, additional research is needed on species-specific responses, sediment types, and geographically focused studies in the lower Chesapeake Bay. My research addresses these gaps by combining both greenhouse …

Transcriptomic Study On The Effect Of Salt Stress In Sorghum Bicolor Seedlings, Joshwa A. Gandy

Theses and Dissertations

The global impact and reliance on cereal crops, and sorghum in particular, is paramount for worldwide food security and for the livelihood of hundreds of millions of people. The detrimental effects of salt stress on crop plants and the huge economic losses it causes by affecting agricultural output worldwide is a devastating issue with huge impacts, which have prompted research to combat salinity in numerous ways. Understanding how cereals respond to the negative effects of salt stress is crucial for enhancing their salt tolerance. In this study of sorghum, we used a 3’-end RNA sequencing approach to elucidate major salt …

Insights Gained From Applying Molecular Techniques To Gray Triggerfish (Balistes Capriscus Gmelin, 1789) In The Mexican Caribbean, The Southern And Northwestern Gulf Of Mexico, Geaceli G. Orive

Theses and Dissertations

This study focuses on Balistes capriscus (Gray Triggerfish), a reef-associated species dependent on hard-bottom habitats in the Gulf of Mexico (GOM). Using mitochondrial DNA barcoding and phylogenetic analyses, genetic structure across four sites was assessed: Rio Grande Valley (RGV), Veracruz, Chinchorro Bank, and Xahuayxol. Samples from RGV and Veracruz exhibited limited haplotype diversity, minimal nucleotide divergence, and weak genetic differentiation-patterns consistent with recent population expansion and ongoing connectivity within the GOM. While the study centered on B. capriscus, all individuals from Chinchorro and Xahuayxol unexpectedly grouped with Canthidermis maculata (Spotted Oceanic Triggerfish), suggesting misidentification, cryptic diversity, or taxonomic uncertainty in …

Analyzing How Taste And Nutrition Impact Learning And Memory In Honey Bees Through Olfactory Associative Conditioning, Alessandra Elizabeth Perry

Theses and Dissertations

Honey bees detect sweet nectar, but not all sweet-tasting sugars provide nutrition. Unlike fruit flies, which can learn to avoid non-nutritious sweet foods, bees may lack this ability. To test if bees form caloric frustration memory (CFM), we conditioned them using odors paired with L-glucose (sweet but non-nutritious) or D-glucose (sweet and nutritious). Bees rewarded with L-glucose showed lower learning and long-term memory compared to D-glucose. Bees cannot differentiate between an odor associated with rewards containing malaise-causing compounds and an odor associated with a reward alone during differential conditioning. Therefore, we used differential conditioning to determine if lower acquisition in …

Comparison Of Recovery Methods After Resistance Exercise For Power Performance, Isaac D. Huerta

Theses and Dissertations

Elite athletes engage in intense training to secure marginal performance advantages, placing considerable physical strain on their bodies. Effective recovery techniques are critical to rapidly restore physical function. Conventional methods like ice baths, hydrotherapy, and massages are often impractical due to cost and logistical barriers. This study examined the efficacy of voluntary deep slow breathing (VDSB) as a cost-effective recovery method compared to static stretching (SS) and no recovery method (control) in untrained male athletes aged 18–26. Using a within-subjects, randomized crossover design over four weeks, participants visited the lab seven times to complete a standardized full-body workout involving plyometric …

Plant Nutrient Interactions In High-Yielding Soybean Environments, Victoria Inklman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Plant nutrient demands and limitations are usually studied individually by nutrient. Here, we investigated how nitrogen (N) limitation in high-yielding soybean environments affects the uptake, removal, and residual of other plant macro- and micronutrients. The objective of this study was to quantify the uptake, removal, and residual levels of soybean macro- and micronutrients under N-limited conditions and to identify nutrient priorities for high-yielding soybean systems. Aboveground plant samples at physiological maturity were collected in 19 high-yielding soybean fields with N limitation across the state of Nebraska. Reference plots with ample N supply were included within each field to compare macro- …

Assessing Long-Term Changes In Aspen Forest Cover In Northern Yellowstone National Park Before And After Carnivore Recovery, Nicholas J. Bergeron

All Graduate Theses and Dissertations, Fall 2023 to Present

The recovery of large carnivores (wolves, bears, cougars) in Yellowstone National Park and the subsequent decline of the area's elk herd have raised key questions about ecosystem restoration—particularly for species such as aspen, which are heavily browsed by elk. Following wolf reintroduction in the mid-1990s, scientists began tracking changes in browsing intensity and height of young aspen within sampling plots, assuming reduced browsing and taller stems were signs of population recovery. However, no studies have measured whether the total area covered by aspen stands actually increased, as would be expected with broader recovery. Moreover, the potential influence of climate change …

Cucurbit Plant Defenses Against Aboveground Or Belowground Insect Herbivores Are Distinct And Shaped By Eco-Evolutionary Factors, Morgan N. Thompson, Emily M. Russavage, Jeremy G. Garces, B. Jack Bradford, Danielle Merrell, Charles P.-C. Suh, Anjel M. Helms

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Plant defense strategies against insect herbivores are classified broadly as resistance or tolerance. Resistance deters insect growth or feeding, while tolerance mitigates negative effects of herbivory on plant fitness. Plant investment into resistance or tolerance strategies likely falls along a continuum that has been shaped by eco-evolutionary factors, such as plant domestication or coexistence histories with herbivores. Relatively little is known about how general defense strategies differ against aboveground foliar herbivores and belowground root herbivores. In the current study, we investigated defense strategies of plant species in the gourd family (Cucurbitaceae) against aboveground squash bug (Anasa tristis) or …

What’S The Beef With Agriculture? Evaluating The Effectiveness Of An Agricultural Literacy Intervention On Students’ Attitudes And Knowledge Toward Sustainability And Animal Agriculture, Jenny E. Bennett

All Graduate Theses and Dissertations, Fall 2023 to Present

Agricultural literacy is essential for helping individuals understand how food systems impact their daily lives and society. While most research has focused on students’ knowledge, this study addresses the underexplored role of attitudes—critical predictors of behavior—as outcomes of educational interventions. This research analyzed survey data collected before and after an agricultural literacy intervention delivered to high school students in school-based agricultural education (SBAE) programs. The curriculum focused on sustainability in animal agriculture.

Findings from paired samples t-tests showed statistically significant improvements in students' attitudes (from moderately neutral to more positive) and knowledge scores. Further analyses revealed that demographic factors such …

Electrophysiological Markers Of Emotion Dysregulation In Autistic Youth, Rachel G. Mcdonald

Theses, Dissertations and Culminating Projects

Emotion dysregulation (ED) is a transdiagnostic mechanism that is conceptualized as difficultly regulating emotions and deploying appropriate regulation strategies in response to environmental stimuli. Meta-analyses suggest that autistic people, across the lifespan, experience more severe ED as compared to both neurotypical people and those with mental health conditions. Despite elevated risk and evidence linking ED to disruptions in neural mechanisms, no studies to date have examined neural markers of ED in autistic populations. The current project uses multi-method and multi-informant measurement to examine similarities and differences in neural mechanisms of ED in autistic and non-autistic populations. Forty-four youth aged 11—17 …

Regulation Of Icer Degradation And Its Role In Melanoma, Justin Wheelan

Theses, Dissertations and Culminating Projects

Melanoma is the deadliest form of skin cancer, with 100,640 new cases and 8,290 deaths estimated in the United States in 2024. While targeted therapies and immunotherapy have improved patient outcomes, resistance remains a major challenge, necessitating new therapeutic approaches. Approximately 50% of melanomas harbor BRAFⱽ⁶⁰⁰ᴱ mutations, leading to constitutive MAPK pathway activation. Targeted small molecule therapies such as BRAF and MEK inhibitors are available and initially reduce tumor burden, however resistance frequently occurs, likely through many pathways including compensatory activation of cAMP signaling. ICER (Inducible cAMP Early Repressor), a transcriptional repressor of CREB-mediated gene expression, is absent in melanoma …

The Effects Of Different Volume-Load On Sprint And Change Of Direction Performance, Damar K. Bobb

Electronic Theses and Dissertations

This study was designed to compare the effects of two different strength training protocols on sprint and change of direction (COD) performance in recreationally trained athletes. Participants were evaluated on maximal dynamic (1RM squat) and isometric (IMTP) strength, speed (30m sprint), and COD (5-0-5 test). The participants were divided into two groups (Low volume-heavy load group [LV], High volume-moderate load high-intensity endurance (HIE) group [HV]) after initial testing, for a 4-week training intervention using traditional and weightlifting derivative lifts. The training consisted of 5 sessions per week (3 sessions resistance training [RT], each about 40-50 mins; 2 sessions sprint & …

Isolation And Characterization Of Siderophore(S) From Pseudomonas Mosselii, Casey J. Stophel

Electronic Theses and Dissertations

Iron is essential for growth of most microorganisms. It functions as an important cofactor in many important biological processes. However, iron found in soil is rendered insoluble and unavailable to microorganisms for use. To overcome this, many bacterial species produce siderophores, a small organic molecule that has high affinity for iron. Siderophores allow for bacterial cells to obtain otherwise insoluble iron. Pseudomonas mosselii, a Gram negative bacterium, was isolated from a local soil sample. P. mosselii was found to produce siderophore(s) under iron restricted environment, however, they have not been characterized. Therefore, it was of interest to isolate, purify and …

Orchestrated Architecture Dismantling: Borrelia Burgdorferi’S Coordinated Destruction Of Adaptive Immune Responses, Craig A. Land

Electronic Theses and Dissertations

Borrelia burgdorferi represents the most prevalent vector-borne bacteria in North America, affecting ~476,000 Americans annually yet persisting despite robust immune responses. This project reveals spirochetes target adaptive immunity through coordinated lymphatic colonization and precision immune dysregulation.

Using comparative host models (C57BL/6 vs. reservoir Peromyscus leucopus), we demonstrate lymph node colonization within 48-hours, with spirochetes exploiting LYVE-1-positive lymphatic structures as dissemination highways while avoiding the interior of follicular regions. Critically, we identify targeted CD4+ T-cell elimination in germinal center border zones at 21-DPI, precisely when these cells should be coordinating protective immunity. Concurrent upregulation of inhibitory receptor CD32b creates molecular …

Improved Autofluorescence Lifetime Decay Analysis For Identification Of Cellular Autofluorescence Biomarkers For Label-Free, Single-Cell Assessment Of Mitochondrial Membrane Potential, Olivia Isabel Kolenc

Graduate Theses and Dissertations

Optical imaging of metabolism using the autofluorescence of the metabolic cofactors NADH, NADPH, and FAD has a wide range of sensitivities and the capability to collect a great deal of metabolic information. Multiphoton microscopy (MPM) is a non-invasive, label-free optical imaging technique capable of performing fluorescence lifetime imaging (FLIM) using time correlated single photon counting (TCSPC). However, autofluorescence FLIM presents a challenge in collecting sufficient photons to provide adequate signal to noise ratios (SNR) for analysis. Additionally, the specificity of autofluorescence biomarkers of metabolism has not been well-defined. Contextualizing these autofluorescence measures using established functional biomarkers can improve interpretability of …

Host-Virus Interaction Dynamics Using Sulfolobus Spindle-Shaped Virus And Host Sulfolobales System, Yeasin Ahmed

Graduate Theses and Dissertations

The Sulfolobus Spindle-shaped virus (SSV) is among the most studied archaeal viruses, particularly in extreme environments. This virus predominantly infects multiple Crenarchaea from the Sulfolobaceae family. These hosts thrive in extreme environmental conditions, such as sulfuric hot springs, with a pH of 2 to 4 and a temperature of 76-80˚C. Sulfolobales exhibit a wide geographical distribution across volcanic hot springs. The Sulfolobus Spindle-shaped Virus (SSV), encompassing strains such as SSV1 and SSV8, employs a non-lytic replication strategy in hosts belonging to the order Sulfolobales. The SSV-Sulfolobales system can be cultured in liquid and gellan gum solid media. A comprehensive study …

Examining The Use Of Two-Dimensional Video Capture And A Pressure Sensing Walkway For Collection Of Obstacle Crossing Measures, Ashlyn M. Jendro

Graduate Theses and Dissertations

Obstacle crossing research is crucial for providing insights into how and why people trip and fall. However, a growing body of literature has proposed that laboratory-based studies may not directly translate into real-world settings due to the complex nature beyond the sterile lab. Unfortunately, the absence of real-world obstacle crossing literature is likely due to a lack of available validated methods for collection of data outside the laboratory. This dissertation explored two potential methodologies (i.e., 2D motion capture and a pressure sensing walkway) that are more portable and cost-effective for collecting real-world obstacle crossing measures. It is hypothesized that 2D …

Freezing And Shipping Optimization To Increase Quality And Profitability Of Meat E-Commerce, Paul Olaoluwaniyi Dahunsi

Graduate Theses and Dissertations

Freezing remains one of the most reliable methods for preserving meat quality and extending shelf life. However, quality deterioration can still occur due to structural and biochemical changes activated during freezing, thawing, and distribution. Since the COVID-19 pandemic, consumers’ preference for bulk purchasing and online meat shopping has increased, raising questions about the best strategies to balance both quality maintenance and profitability. This thesis aimed to evaluate two key stages where frozen beef is most vulnerable to quality degradation: consumer-level freezing and post-purchase shipping. The objectives were (1) to determine the effects of product size and subsequent consumer freezing practices …

A Multicomponent Microneedle Patch For The Delivery Of Meloxicam For Veterinary Applications, Katherine Alejandra Miranda Munoz

Graduate Theses and Dissertations

Veterinary medicine requires innovative drug delivery strategies to enhance therapeutic efficacy while minimizing stress and handling. This dissertation explores the development and application of biodegradable microneedle patches for the transdermal delivery of meloxicam in livestock, offering a minimally invasive alternative to traditional administration methods. The research investigates the fabrication and characterization of microneedles using polyvinyl alcohol, collagen, and chitosan blends, demonstrating their mechanical strength, biocompatibility, and ability to facilitate sustained drug release. In vitro and in vivo evaluations confirm effective skin penetration, dissolution, and localized drug delivery. Pharmacokinetic studies highlight anatomical site-dependent variations in drug absorption, emphasizing the need for …

Small Angle X-Ray Scattering Studies Of Collagenase H Mutant, Colh-E416q, Madelyn Millsap

Graduate Theses and Dissertations

Collagenase H (ColH) from Hathewaya histolytica plays a central role in collagen degradation through endopeptidase and carboxytripeptidase reactions. To better understand how its domain architecture supports these functions, we examined the solution structure of a catalytically inactive mutant, ColH-E416Q, using small-angle X-ray scattering (SAXS). The E416Q mutant is catalytically inactive because the glutamate residue at position 416, which normally functions as a general acid/base during catalysis, is replaced by glutamine—an amide that cannot donate or accept protons effectively, thus disabling the proton transfer steps essential for peptide bond hydrolysis. SAXS results indicate that the E416Q substitution leaves overall domain architecture …