College of Agriculture & Natural Resources

Permanent URI for this communityhttp://hdl.handle.net/1903/1598

The collections in this community comprise faculty research works, as well as graduate theses and dissertations.

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Now showing 1 - 10 of 1651
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    Aligning Renewable Energy Goals with Rural Land Use: Educational Needs for Solar Development Contracts in New York and Maryland
    (2024) Thilmany, Elizabeth; Goeringer, Paul; Kay, David; Chatrchyan, Allison
    The rapid expansion of utility-scale solar projects in the U.S. brings opportunities and challenges to rural communities, affecting land use and agricultural practices. This growth, fueled by falling costs and supportive government policies, prompts states to diversify their energy portfolios with more renewables, creating tension over agricultural land use for solar development. Maryland and New York’s ambitious renewable energy targets highlight the urgency of a nuanced understanding of these issues. Our research emphasizes the importance of spatially informed decision-making at the individual landowner level to effectively address potential zoning and land-use conflicts. Preliminary findings suggest a significant need for educational resources that help landowners navigate negotiations and mitigate agricultural impacts. Additionally, our work identifies a gap in the knowledge base of rural attorneys, who require more comprehensive information to support landowners in the complex realm of solar energy contracts. By focusing on the specific needs of rural communities, our study aims to promote equitable large-scale, ground-mounted solar development. This involves shaping policy interventions and offering targeted educational resources to ensure solar expansion meets clean energy goals while respecting rural land-use realities.
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    Antimicrobial peptide class that forms discrete beta-barrel stable pores anchored by transmembrane helices
    (Nature Communications, 2025-06) Dickey, Seth W.; Burgin, Dylan J.; Antwi, Ama N.; Villaruz, Amer; Galac, Madeline R.; Cheung, Gordon Y. C.; Rostovtseva, Tatiana K.; Worrall, Liam J.; Lazarski, Aleksander C.; Cino, Elio A.; Tieleman, D. Peter; Bezrukov, Sergey M.; Strynadka, Natalie C. J.; Otto, Michael; Dickey, Seth; Otto, Michael
    Bacteriocins are weapons of inter-bacterial warfare and belong to the larger group of antimicrobial peptides (AMPs), which are frequently proposed as alternatives to antibiotics. Many AMPs kill by destroying the target’s cytoplasmic membrane using short-lived membrane perturbation. Contrastingly, protein toxins form large pores by stably assembling in the target membrane. Here we describe an AMP family we termed TMcins (for transmembrane helix-containing bacteriocin), in which half of the AMP forms a transmembrane helix. This characteristic allows TMcin to assemble into stable and large oligomeric pores. The biosynthetic locus of TMcin, which was broadly active against Gram-positive bacteria, is distributed throughout two major bacterial phyla, yet bears no homology to previously reported bacteriocin biosynthetic gene clusters. Our discovery of an AMP class that achieves pore stability otherwise only found in protein toxins transforms our current understanding of AMP structure and function and underscores the continuing importance of phenotype-initiated investigations in uncovering wholly uncharacterized antimicrobials.
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    Evaluating the Effectiveness of Economic Incentives to Enhance Riparian Buffer Adoption and Environmental Benefits for Water Quality and Carbon Sequestration in Maryland
    (2024-10) Newburn, David; Lichtenberg, Erik; Kim, Youngho; Wietelman, Derek; Wang, Haoluan
    This report assesses the effectiveness of economic incentives in encouraging Maryland farmers to adopt riparian buffers for improved water quality and carbon sequestration. Using a statewide landowner survey and integrated environmental-economic modeling, the study evaluates program design features such as payment type, contract length, and targeting. Results show that upfront payments increase participation, targeted bonuses improve cost-effectiveness, and carbon offset payments offer limited added benefit. Policy recommendations focus on enhancing program efficiency through strategic incentive design.
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    EFFECTS OF FOOD PROCESSING METHODS ON PHENOLIC ACIDS AND ANTIOXIDANT CAPACITY IN SWEET CORN
    (2024) Dong, Fangxiang; Yu, Liangli; Agricultural and Resource Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This thesis research was designed to evaluate the effects of different food processing methods on the phenolic acid and antioxidant properties of sweet corn. Phenolic acids, such as ferulic acid and p-coumaric acid, are known for their health benefits. The research primarily focuses on two main stages of food processing: post-harvest handling and domestic cooking (boiling and steaming. These processes are evaluated to determine their impact on the soluble free, soluble conjugated, and insoluble bound forms of phenolic acids in sweet corn.Phenolic acids were analyzed by High-Performance Liquid Chromatography (HPLC). The study found that post-harvest handling significantly reduced the phenolic acid content, particularly in the insoluble bound form. Domestic cooking also led to notable reductions in phenolic content, though antioxidant activity, as measured by DPPH and ABTS assays, showed varying responses, sometimes increasing in treated samples. It was noted that different processing methods can induce structural changes that may either preserve or enhance the antioxidant properties. Furthermore, the results of this thesis explored optimal food processing techniques to maximize the retention of bioactive compounds, providing insights for better food preservation strategies.
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    ZIKA VIRUS RECRUITS CELLULAR PROTEINS TO SUPPORT ITS REPLICATION
    (2024) Chang, Peixi; Zhang, Yanjin YJ; Veterinary Medical Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Zika virus (ZIKV) is a mosquito-borne pathogen with a massive impact on global public health due to its association with severe neurological complications, including microcephaly in newborns and Guillain-Barré syndrome in adults. The ZIKV epidemic in the Americas in 2015-2016 and its continuing spread in tropical regions have highlighted the urgent need to understand the molecular mechanisms of viral replication to develop effective antiviral strategies. However, many aspects of how ZIKV interacts with host cells remain unclear. This study identifies and characterizes host factors contributing to ZIKV replication. First, karyopherin alpha 6 (KPNA6) contributes to ZIKV replication by interacting with the ZIKV non-structural protein NS2B. Characterization and mutational analyses identified two essential amino acid residues within NS2B that are critical for interacting with KPNA6. The substitution of these two residues of NS2B in an infectious ZIKV cDNA clone resulted in a significant reduction in viral replication, suggesting that the NS2B-KPNA6 interaction plays a vital role in the viral life cycle. Further studies found that KPNA6 contributes to ZIKV RNA synthesis. Mass spectrometry analysis of the KPNA6 interactome showed that KPNA6 interacts with proteins involved in RNA synthesis, suggesting that ZIKV recruits these factors by promoting KPNA6-binding. Second, this study developed an effective method to isolate the ZIKV replication complex, a membranous structure where viral RNA is synthesized. Proteomic analysis of the isolated complex led to identifying numerous host proteins associated with the viral replication machinery. Among these proteins, human replication factor C subunit 2 (RFC2), an accessory factor involved in DNA replication and repair, was discovered to facilitate ZIKV replication, making it a potential target for therapeutic interventions. In conclusion, this study reveals crucial host factors essential for ZIKV infection and replication and provides insights into the ZIKV-cell interactions. These findings offer new possibilities for developing novel antiviral strategies for controlling future viral outbreaks.
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    DEVELOPMENT OF CHITIN NANOCRYSTALS AND THEIR APPLICATIONS IN FOOD AND AGRICULTURAL AREAS
    (2024) Jia, Xiaoxue; Wang, Qin; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Seafood industry generates millions of tons of waste annually, with crustacean shells being a significant component. Discarding these shells not only exacerbates environmental pollution but also represents a missed opportunity for resource recovery. This dissertation research aims to address these environmental challenges by repurposing crustacean shell waste into high-value nanomaterials, specifically chitin nanocrystals (ChNCs), and exploring their applications in the food, agricultural, and environmental sectors. The primary objective of this study is to investigate the fabrication, functionalization, and potential industrial applications of ChNCs, thereby offering a sustainable alternative to conventional synthetic materials.Traditional chitin nanocrystals ChNCs obtaining methods rely on strong acids, posing environmental risks. This research introduces a more sustainable phosphoric acid (PA) hydrolysis method, which uses significantly lower acid quantities, reduces environmental impact, and avoids corrosive waste. Moreover, the novel PA hydrolysis occurs in the solid state and can be handled by hand, simplifying operation. This method efficiently yields uniform ChNCs with positive surface charges (~+27 mV), suitable for scalable industrial applications. Additionally, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) oxidation was employed to produce oxidized chitin nanocrystals (O-ChNCs) with negative surface charges (~ −56 mV). ChNCs and O-ChNCs were investigated as stabilizers in Pickering emulsions. Both were able to significantly enhance the stability of oil-in-water (O/W) emulsions, particularly when pH > 9. O-ChNCs further demonstrated encapsulation efficiencies of up to 80% for bioactive compounds like quercetin, highlighting their potential in food and nutraceutical delivery systems. Additionally, ChNCs and O-ChNCs were incorporated into a colorimetric sensor array (CSA) to monitor beef freshness. The negative charged O-ChNC-based sensor exhibited sensitivity to spoilage gases, achieving 99.3% accuracy in beef freshness detection with the aid of deep learning algorithms. This innovation provides a non-invasive cost-effective method to food quality and safety monitoring. Furthermore, ChNCs were deacetylated to form chitosan nanocrystals (ChsNCs), and subsequently modified with zinc to create a ChsNCs@Zn composite for the removal of per- and polyfluoroalkyl substances (PFASs) from water. The composite achieved 50% PFAS removal within 5 minutes and ultimately achieved 68% removal, showcasing strong adsorption capabilities and offering a potential sustainable solution for PFAS remediation in contaminated water sources. In summary, this research is driven by the need to solve the environmental problem of seafood waste, while also tackling challenges in food stability and safety, as well as water purification. The findings contribute to advancing sustainable materials and practices in response to pressing environmental challenges.
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    ROLE OF TRPV4 MECHANOSENSING REGULATING MACROPHAGE FUNCTIONS IN INFLAMMATORY DISEASES
    (2024) Dutta, Bidisha; Rahaman, Shaik O; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Macrophages are the most versatile cells of the hematopoietic system with roles in homeostasis, host-tissue development, innate immune response and tissue repair. Although the inflammatory activation and maintenance signals are tightly regulated, an imbalance in them results in unchecked inflammation resulting in cellular and tissue damage. Macrophages can affect most if not all phases of inflammation owing to their ability to adopt distinct functional states, secrete cytokines and phagocytose pathogens and debris. Recent evidence suggests that beyond biochemical cues, mechanical forces, like changing matrix stiffness in the tissue microenvironment, can shape immune cell functions involved in inflammation. These cells convert mechanical stimuli to biochemical signals in a process called mechanotransduction, regulating a multitude of cellular functions. However, knowledge about the molecular mediators of mechanotransduction and their functions in macrophage phenotypic and functional change is largely missing, highlighting the need for studying mechanosensory molecules such as ion channels. The present study focuses on the role of a specific mechanosensitive ion channel, Transient Receptor Potential Vanilloid 4 (TRPV4), in the regulation of macrophage mediated inflammatory responses. Given its emerging role in inflammatory diseases like fibrosis, arthritis, foreign body response (FBR), TRPV4’s contribution to macrophage behavior in inflammation is of growing interest. Employing cellular imaging and molecular biology techniques such as Ca2+ influx assays, immunohistochemistry, immunoblotting, and single nuclei RNA sequencing we delineate mechanisms by which biomechanical stimuli-mediated activation of TRPV4 affects macrophage function. We elucidate TRPV4’s role in macrophage mechanotransduction, providing a mechanistic understanding of inflammatory disease pathophysiology which could lead to the development of potential therapeutics for disease intervention.
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    MEDIATION OF CORTICOSTERONE-INDUCED GROWTH HORMONE GENE EXPRESSION IN CHICKEN EMBRYONIC PITUITARY CELLS: IDENTIFICATION OF TRANS-ACTING FACTORS AND A NOVEL PITUITARY CELL TYPE
    (2024) Liu, Kuan Ling; Porter, Tom E.; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Growth hormone (GH) is responsible for up to 30% of growth in broiler chickens. Somatotrophs, or GH secreting cells, begin to differentiate around embryonic day (e)14, in conjunction with an increase in the primary plasma glucocorticoid (GC) corticosterone (CORT). CORT treatment of e11 chicken embryonic pituitary (CEP) cells induces premature GH secretion. This GC-induced process involves trans-acting factors because the GH gene lacks a canonical GC response element (GRE). In addition to the binding of ETS1 and the GC receptor (GR) to the GC-responsive region (GCRR; 1045/ 964), we hypothesize that there are other regulatory factors necessary for CORT responsiveness. By modifying the pGL3_-1742/+25 GH-luciferase reporter, we have constructed various other GH-luciferase reporters and analyzed them for promoter activity in response to CORT treatment. We identified a putative distal (d) ETS-Like 1 (ELK1) binding site that is necessary. The proximal (p)PIT1 site and pTATA box were also identified to be critical for CORT induction of the GH gene. Interestingly, cloning multiple copies of the extended GCRR (eGCRR; -1067/-900) further increased promoter activity in an additive manner under both basal and CORT treated conditions. Through single-cell RNA sequencing (scRNAseq), 8 members of the ETS family of transcription factors were identified in > 5% of the somatotroph population. Commercial antibodies were validated, and human (h)ETV1, hELF2, hELK3, and hETV6 antibodies were confirmed to recognize their recombinant chicken ortholog and to identify their corresponding protein in e11 CEP cells. Results from chromatin immunoprecipitation quantitative PCR suggest that multiple ETS members are involved in CORT induction of the GH gene with more evidence pointing towards ELF2 and ELK3. Identifying trans-acting factors for the GH gene inducible by CORT allows for better understanding of endogenous GH regulation in chickens. Further analysis of the scRNAseq data from e11 CEP cells revealed a cluster of cells expressing genes for more than one hormone-producing cell type (“premature nebulous” cluster). Within the premature nebulous cluster, a large population (~30%) was co-expressing proopiomelanocortin (POMC) and growth hormone (GH). We named this novel cell population the cortico-somatotrophs. Through RNA fluorescent in-situ hybridization (RNA-FISH) and dual label immunofluorescence, we verified the existence of the cortico-somatotrophs at both the mRNA and protein level, respectively. Cortico-somatotrophs were also shown to share genes for receptors normally specific to both corticotrophs (CRH-R1) and somatotrophs (GHRHR). Additionally, in response to CORT treatment, the cortico somatotrophs showed an increase in GH as well as a decrease in POMC mRNA levels. The discovery of the cortico-somatotrophs suggests a modification to the current dogma on pituitary cell lineages, where corticotrophs and somatotrophs may have overlapping developmental pathways. In conclusion, our discovery of the cortico somatotrophs has furthered our understanding of CEP development and opened the door for further exploration of the cell lineages during pituitary development.
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    MACHINE LEARNING AND GENOMICS FOR IMPROVED FOOD SAFETY AND RISK ASSESSMENT OF SALMONELLA ENTERICA IN CHICKEN
    (2024) Benefo, Edmund Ofosu; Pradhan, Abani K; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Salmonella enterica is a leading cause of foodborne illnesses worldwide and is commonly associated with poultry. Salmonella has many closely related serovars, yet these serovars exhibit significant variability in many characteristics including host range, virulence, growth behavior, stress response, and antimicrobial resistance. In the past, this intricate and dynamic population heterogeneity of Salmonella severely hampered control efforts, but, today, this has improved through the sequencing of Salmonella genomes. Whole genome sequencing (WGS) provides a better understanding of the evolutionary and ecological adaptations that underlie the survival of Salmonella against antimicrobials, oxidative agents, non-optimal temperatures, and other stressors in the environment and their hosts. Coupling machine learning with WGS expands on these advantages by enabling the identification of genetic patterns that may not be immediately apparent. The overall goal of this research was to explore how machine learning and genomics can be integrated to improve food safety. First, a machine learning model was developed to identify stress response genes in Salmonella isolated from different poultry processing stages. It was found that beyond genes encoding for cold and heat shock proteins, other genes involved in lipopolysaccharide biosynthesis, DNA repair and replication, and biofilm formation are involved in Salmonella’s overall stress response mechanism. Additionally, a machine learning model was developed to predict antimicrobial resistance (AMR) phenotypes in Salmonella isolates using WGS data. The model predictions were comparable to existing bioinformatic methods for AMR prediction and identified AMR genes that are typically not the resistance determinants public health agencies focus on. Expanding this approach for AMR surveillance could lead to the discovery of novel AMR genes. Lastly, a quantitative microbial risk assessment for Salmonella in chicken that incorporated Salmonella heterogeneity in growth and virulence was developed. The findings revealed that variations in virulence have a greater impact on the risk of salmonellosis than variations in growth rate. Overall, this research contributes to efforts to enhance food safety measures and reduce chicken-associated Salmonella illnesses.