Biochemistry Commons^™

Design And Synthesis Of Purine Based Neuroprotectors And Novel Synthetic Methods For The Trifluoromethylation Of Aldehyde Hydrazones, Puspa Aryal

Doctoral Dissertations

"Purine-derived compounds are widely investigated as cyclin-dependent kinase inhibitors that have broad applications in the design of pharmaceuticals for treating diseases, such as diabetes, atherosclerosis, and cancers. Towards the goal of effective AGE-inhibitors, and neuroprotector compounds we have synthesized a series of novel purine-based triazoles and investigated their neuroprotective effects, using SHSY-3Y human neuroblastoma cell line. Through these studies, we have identified purine-based neuroprotector compounds that favorably modulate oxidative stress induced by the Fenton reaction-generated reactive oxygen species (ROS).

The C(sp²−H)-trifluoromethylation of hydrazones would give access to the αtrifluoromethylated hydrazones that can serve as intermediates in the synthesis …

Protumorigenic Effects Of Mixed Lineage Kinase Domain-Like Protein In Cholangiocarcinoma Cells, Nattaya Duangthim

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cholangiocarcinoma (CCA), a heterogeneous malignancy of bile duct system, has the highest incidence in Thailand. CCA is one of the leading causes of death which has low 5-year survival rate from 5% to 10% in advanced stages due to the difficulty of diagnosis in early stage and lack of effective therapies. Therefore, understanding the molecular mechanisms and pathogenesis of CCA development and progression is urgently needs and will lead to the development of novel therapeutic targets and strategies. Mixed lineage kinase domain-like (MLKL) was identified as a key effector in a novel regulated necrosis or necroptosis pathway. Recently studies have …

Roles Of Regulated Cell Death In Cholangiocarcinoma And Pancreatic Ductal Adenocarcinoma, Thanpisit Lomphithak

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cholangiocarcinoma (CCA) and pancreatic ductal adenocarcinoma (PDAC) are complex and heterogeneous cancers. Conventional therapy approaches often fail to elicit significant responses in patients, resulting in low survival rates compared to other cancer types. This could be due to their immunosuppressive and desmoplastic tumor microenvironment, which renders cancer cells resistant to conventional therapies, highlighting the urgent need for more effective therapeutic approaches. Regulated cell death pathways have been extensively studied in recent years as a promising target for developing new strategies in cancer treatment. Specifically, necroptosis and ferroptosis, two forms of regulated necrosis, hold promise as novel targets for treating cancer, …

Isolation And Characterization Of Bacteriophage Targeting Acute Hepatopancreatic Necrosis Disease-Causing Vibrio Parahaemolyticus, Khrongkhwan Thammatinna

Chulalongkorn University Theses and Dissertations (Chula ETD)

Vibrio parahaemolyticus causing Acute hepatopancreatic necrosis disease (VPAHPND) has been a major cause of serious shrimp aquaculture economic losses. Moreover, many isolates have exhibited the resistance of various antibiotic drugs. Most recently, bacteriophage or phage, the killer of bacteria, has been gaining interest as an alternative tool to prevent and control pathogens. In this study, we discovered two novel vibriophages - vibriophage Seahorse and vibriophage phiKT1024 – that target various strains of VPAHPND. vibriophage Seahorse and vibriophage phiKT1024 were assigned to the family Siphoviridae and Myoviridae, respectively. Based on the cut-off of genome size that is less than 200 kbp …

Role Of Jak/Stat Signaling Pathway During Viral Infection In Black Tiger Shrimp Penaeus Monodon, Pasunee Laohawutthichai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Janus Kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway plays an important role for antiviral immunity. To stimulate the pathway, the cytokines, interferons, or other stimulators activate the receptor, which is then dimerized and activate JAKs, causing phosphorylation of the tyrosine residues of the receptor. Consequently, STATs are phosphorylated, dimerized and localized into the nucleus to regulate their target gene transcription. This study aims to better understand the role of JAK/STAT signaling pathway in Penaeus monodon during viral infection. From tissue distribution, PmDOME, PmJAK and PmSTAT transcripts were expressed in all tested tissues and up-regulated about 2-fold upon WSSV …

Isolation And Characterization Of Methyl Viologen-Resistant Synechocystis Sp. Pcc 6803 Mutants, Jidapa Leksingto

Chulalongkorn University Theses and Dissertations (Chula ETD)

Methyl viologen (MV) is a widely used herbicide that competes electrons from photosystem I and induces the formation of active radical species causing cellular oxidative stress in plants and photosynthetic cyanobacteria. However, the exact target molecule of methyl viologen in the cells has yet to be identified. This study aimed to identify the mutation(s) that lead to MV resistance in cyanobacterium Synechocystis sp. PCC 6803. Synechocystis wild type was cultured for 30 days to reach the stationary-growth phase to allow the occurrence of spontaneous mutations in aged cells. Approximately 109 cells were spread on an agar medium containing high MV …

Molecular Mechanism Of Damage-Associated Molecular Patterns In Association With Acute Hepatopancreatic Necrosis Disease Resistance Of Heat Stressed-Shrimp Penaeus Vannamei, Supitcha Wanvimonsuk

Chulalongkorn University Theses and Dissertations (Chula ETD)

Non-lethal heat shock (NLHS) is known to enhance resistance to acute hepatopancreatic necrosis disease caused by Vibrio parahaemolyticus (VPAHPND) in the Pacific white shrimp Penaeus vannamei. Generally, cell damage induced by stresses leads to the release of damage-associated molecular patterns (DAMPs), molecules that act as endogenous danger signals to promote immune response. The first part of this research aims to study molecular mechanism of DAMPs that can enhance innate immunity upon NLHS treatment on VPAHPND resistance. We identified and characterized the candidate NLHS-induced DAMP that can activate innate immune responses against VPAHPND. The candidate DAMP genes were retrieved from the …

Discovery Of Inhibitors Of Peptidoglycan O-Acetyltransferase B (Patb) From Neisseria Gonorrhoeae, A New Potential Antibacterial Target, Stefen Stangherlin

Theses and Dissertations (Comprehensive)

Experts project that by 2050, 10 million lives will be lost annually as a result of antimicrobial resistant infections, surpassing all current leading causes of death, and costing the global economy $100 trillion USD on healthcare efforts. To promote research and development of novel antibiotics, the World Health Organization and Centers for Disease Control and Prevention released a list of priority pathogens regarded as serious or urgent threats of antimicrobial resistance. Many pathogenic bacteria, including several priority pathogens, produce O-acetylated peptidoglycan to establish infection and avoid host immune responses. Consequently, the enzymes responsible for producing O-acetylated peptidoglycan in Gram-negative pathogenic …

ฮอร์โมนเอสโตรเจนเหนี่ยวนำให้เกิดการแทรกของ Line-1 ดีเอ็นเอเข้าไปในจีโนมของเซลล์มะเร็งเต้านม, กุลจิรา โรจน์ไพศาลกิจ

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในปัจจุบันโรคมะเร็งเต้านมเป็นมะเร็งที่มีอุบัติการณ์และอัตราการตายสูงที่สุดในเพศหญิงทั่วโลกรวมถึงในประเทศไทยด้วย โดยพบว่า LINE-1 ถือว่าเป็น Retrotransposon element ที่พบมากที่สุดถึง 17 % ของจีโนมและมีความสามารถในการคัดลอกแล้วแทรกตัวเองในบริเวณอื่นของจีโนมซึ่งเป็นสาเหตุของทำให้เกิดความไม่สเถียรของจีโนมอันเป็นสาเหตุของการเกิดโรคมะเร็ง และยังพบว่าการแสดงออกของLINE-1 มีผลต่อการลุกลาม, ขนาด, และระยะของโรคมะเร็งเต้านมด้วย นอกจากนี้ยังพบว่าผู้หญิงที่การได้รับฮอร์โมนเอสโตรเจนต่อเนื่องเป็นระยะเวลานานทำให้ความเสี่ยงของโรคมะเร็งเต้านมเพิ่มมากขึ้น ถึงกระนั้นยังคงไม่ทราบถึงกลไกการทำงานของเอสโตรเจน ดังนั้นผู้วิจัยจึงตั้งสมมุติฐานว่า เอสโตรเจนสามารถเหนี่ยวนำให้เกิดการแทรกของ LINE-1 ดีเอ็นเอเข้าไปในจีโนมของเซลล์มะเร็งเต้านม โดยทำการศึกษาบผลของเอสโตรเจนที่ได้รับต่อการแสดงออกของ LINE-1 mRNA และ LINE-1 โปรตีน รวมถึงผลของเอสโตรเจนที่ได้รับต่อการแทรกของ LINE-1 ดีเอ็นเอโดยวิเคราะห์จากปริมาณดีเอ็นเอในเซลล์มะเร็งเต้านม T47D ผลการทดลองพบว่าที่เอสโตรเจนมีผลทำให้การแสดงออกของ LINE-1 mRNA เพิ่มขึ้นสูงที่สุดอย่างมีนัยสำคัญที่ความเข้มข้นของเอสโตรเจน 5 nM ด้วยวิธี Realtime RT-PCR ในเซลล์มะเร็งเต้านม T47D และผลทำให้การแสดงออกของ LINE-1 mRNA เพิ่มขึ้นสูงที่สุดอย่างมีนัยสำคัญที่ 12 ชม. ด้วยวิธี Realtime RT-PCR ในเซลล์มะเร็งเต้านม T47D และเอสโตรเจนมีผลทำให้การแสดงออกของโปรตีน LINE-1 ORF1p เพิ่มขึ้นสูงที่สุดอย่างมีนัยสำคัญที่ 48 และ 72 ชม. ในเซลล์มะเร็งเต้านม T47D ด้วยวิธี Western blot โดยพบว่าการแสดงออกของโปรตีน LINE-1 ORF1p เพิ่มขึ้นสูงที่สุดอย่างมีนัยสำคัญ 72 ชม. นอกจากนี้เอสโตรเจนมีผลทำให้ปริมาณของ LINE-1 ดีเอ็นเอบริเวณ ORF2 เพิ่มขึ้นสูงที่สุดอย่างมีนัยสำคัญที่ 72 ชม.ในเซลล์มะเร็งเต้านม T47D มากที่สุดอย่างมีนัยสำคัญด้วยวิธี Real-time PCR แสดงให้เห็นว่าเอสโตรเจนมีผลทำให้เกิดการแทรกของ LINE-1 ดีเอ็นเอเข้าไปในจีโนมได้ จากผลการทดลองทั้งหมดจึงสรุปได้ว่า เอสโตรเจนมีผลต่อการเพิ่มแสดงออกของ LINE-1 mRNA และ LINE-1 โปรตีน รวมถึงเพิ่มปริมาณ LINE-1 ดีเอ็นเอ อย่างมีนัยสำคัญในเซลล์มะเร็งเต้านม T47D แสดงว่าเอสโตรเจนสามารถเหนี่ยวนำให้เกิดการแทรกของ LINE-1 ดีเอ็นเอเข้าไปในจีโนมนำไปสู่การกลายพันธุ์ของยีนและความไม่เสถียรของจีโนม

Investigating The Main Protease (Mpro) Of Sars-Cov-2 As A Potential Drug Target, Valerie Giovina Pascetta

Honors Theses and Capstones

The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease 19 (COVID-19) pandemic has claimed the lives of roughly 6.2 million people worldwide as of May 2022. The virus’s main protease (M^pro ) has been identified as an attractive drug target due to the critical role it plays in the viral life cycle. The roughly 34 kDa M^pro cleaves functional viral polypeptides out of two long polyproteins at conserved cut sites, allowing them to fulfill their role in processes like transcription and replication. Here, we have studied the enzymatic activity …

Bodipy Based Photodynamic Therapy And Potassium Probes, Xiangshan Liu

Dissertations

Boron dipyrromethene (BODIPY) has become more and more popular in photophysical and biological applications. BODIPY based fluorescence compounds have numerous advantage properties including low toxicity, high absorption extinction coefficients, high fluorescence quantum yields, sharp fluorescence emissions, and resistance to photobleaching. All the good properties lead to the wide applications of BODIPY based compounds. In this research, two different kinds of BODIPY are synthesized. Firstly, BDBrC containing carbazole and BODIPY core is synthesized. Cellular uptake research shows BDBrC can target on lysosome and singlet oxygen generation research result indicates that BDBrC can be used in photodynamic therapy. BDBrC also shows pH-sensitive …

The Utilization Of Enzymes And Enzyme Products For Antimicrobial Effects, Brandon Edward Burdette

Theses and Dissertations

Bacterial resistance is outpacing the discovery of novel antimicrobials. Therefore, it is essential to look at antimicrobials using novel methods. MTAN is a crucial enzyme for some bacteria such as Helicobacter pylori. Transition state analog inhibitor design and fragment-based drug design are drug design approaches typically used independently, but combining these techniques yields inhibitors that bind tightly and are effective in pM concentrations. We demonstrate the efficacy of the combined techniques by investigating the inhibition of HpMTAN, which is an essential enzyme. Enzyme byproducts can also be effective for causing bacterial cell death, hydrolyzing GsdmD by caspases-1/4/5/11 results in an …

Likely Community Transmission Of Covid-19 Infections Between Neighboring, Persistent Hotspots In Ontario, Canada, Ben C. Shirley, Eliseos J. Mucaki, Peter Rogan

Biochemistry Publications

Introduction: This study aimed to produce community-level geo-spatial mapping of confirmed COVID-19 cases in Ontario Canada in near real-time to support decision-making. This was accomplished by area-to-area geostatistical analysis, space-time integration, and spatial interpolation of COVID-19 positive individuals.
Methods: COVID-19 cases and locations were curated for geostatistical analyses from March 2020 through June 2021, corresponding to the first, second, and third waves of infections. Daily cases were aggregated according to designated forward sortation area (FSA), and postal codes (PC) in municipal regions Hamilton, Kitchener/Waterloo, London, Ottawa, Toronto, and Windsor/Essex county. Hotspots were identified with area-to-area tests including Getis-Ord Gi*, Global …

High-Resolution Cryo-Electron Microscopy Structure Of Photosystem Ii From The Mesophilic Cyanobacterium, Synechocystis Sp. Pcc 6803, Christopher J. Gisriel, Jimin Wang, Jinchan Liu, David A. Flesher, Krystle M. Reiss, Hao-Li Huang, Ke R. Yang, William H. Armstrong, M. R. Gunner, Victor S. Batista, Richard J. Debus, Gary W. Brudvig

Publications and Research

Photosystem II (PSII) enables global-scale, light-driven water oxidation. Genetic manipulation of PSII from the mesophilic cyanobacterium Synechocystis sp. PCC 6803 has provided insights into the mechanism of water oxidation; however, the lack of a highresolution structure of oxygen-evolving PSII from this organism has limited the interpretation of biophysical data to models based on structures of thermophilic cyanobacterial PSII. Here, we report the cryo-electron microscopy structure of PSII from Synechocystis sp. PCC 6803 at 1.93-Å resolution. A number of differences are observed relative to thermophilic PSII structures, including the following: the extrinsic subunit PsbQ is maintained, the C terminus of the …

The Phase Behavior Of Ubqln Proteins And Implications For Protein Quality Control, Yiran Yang

Dissertations - ALL

The ubiquitin-proteasome system (UPS) and autophagy are essential pathways for maintaining protein quality control (PQC) in cells. Misfolded proteins and large aggregates are cleared by UPS and autophagy signaled by ubiquitin (Ub) or polyubiquitin (polyUb) chains. Shuttle proteins facilitate cargo transporting by interacting with both ubiquitin and degradation machineries. Previously, our lab discovered that the shuttle protein Ubiquilin-2 (UBQLN2) is recruited to stress granules in cells and undergoes liquid-liquid phase separation (LLPS) in vitro. LLPS is a biophysical process by which proteins separate themselves from the surrounding aqueous solution by forming protein-rich droplets. The overarching goals of this work are …

Direct Single Molecule Imaging Of Enhanced Diffusion For Enzymes And Enzyme-Conjugated Dna Origami, Mengqi Xu

Dissertations - ALL

Enzymes have been shown to diffuse faster in the presence of their substrates. Recently, we revealed new insights into this process of enhanced diffusion using single-particle tracking (SPT) with total internal reflection fluorescence (TIRF) microscopy. We found that the mobility of individual enzymes was enhanced three-fold in the presence of the substrate, and the motion remained Brownian. We showed that the relative increase in diffusion is independent of the total enzyme concentrations; and the oligomerization state of enzymes did not change during the catalytic turnover. These experiments ruled out the possibility that the enhanced enzyme diffusion was caused by the …

Cryptococcus Neoformans Melanization Incorporates Multiple Catecholamines To Produce Polytypic Melanin, Rosanna P. Baker, Christine Chrissian, Ruth E. Stark, Arturo Casadevall

Publications and Research

Melanin is a major virulence factor in pathogenic fungi that enhances the ability of fungal cells to resist immune clearance. Cryptococcus neoformans is an important human pathogenic fungus that synthesizes melanin from exogenous tissue catecholamine precursors during infection, but the type of melanin made in cryptococcal meningoencephalitis is unknown. We analyzed the efficacy of various catecholamines found in brain tissue in supporting melanization using animal brain tissue and synthetic catecholamine mixtures reflecting brain tissue proportions. Solid-state NMR spectra of the melanin pigment produced from such mixtures yielded more melanin than expected if only the preferred constituent dopamine had been incorporated, …

Nuclear Receptor Coactivator 3 In Endoplasmic Reticulum Stress And Stress Granule Dynamics In Pancreatic Cancer, Andrew Kisling

Theses & Dissertations

Pancreatic cancer is predicted to be the second-leading cause of cancer-related deaths within the next decade. Nuclear receptor coactivator 3 (NCOA3/SRC3/AIB1) regulates an array of metabolic and signaling pathways and has been established by our group and others as a critical regulator pancreatic cancer progression and metastasis. A recent study demonstrated NCOA3 regulation by the IRE1α-XBP1 axis of the unfolded protein response (UPR), suggesting a link between NCOA3 and cellular stress management. Furthermore, NCOA3 has been shown to directly bind to a scaffolding protein of stress granules (SGs). Since SG assembly is regulated by the UPR, we hypothesized that NCOA3 …

Functional Characterization Of Cancer-Associated Dna Polymerase Ε Variants, Stephanie R. Barbari

Theses & Dissertations

Replicative DNA polymerases ε (Polε) and δ (Polδ) achieve high fidelity DNA synthesis through a precise balance of polymerization and exonucleolytic proofreading. Errors that escape proofreading are corrected by DNA mismatch repair (MMR). Ultramutated human cancers with proficient MMR carry alterations in the exonuclease domain of Polε, which were initially predicted to abolish proofreading. However, functional studies in yeast of the most recurrent Polε-P286R variant suggested defects beyond a loss of exonuclease activity. Indeed, biochemical analysis of the yeast Polε-P286R analog revealed increased polymerization capacity in addition to decreased proofreading, which enables efficient mismatch extension and bypass of replication-blocking non-B …

A Pkcα-Mediated Growth Suppressive Mek-Erk Signaling Axis In Intestinal Epithelial Cells, Navneet Kaur

Theses & Dissertations

Members of the protein kinase C (PKC) family of serine/threonine kinases are involved in regulation of fundamental cellular functions, including proliferation, differentiation, survival, migration, and transformation. Increasing evidence points to anti-proliferative and tumor suppressive role of PKCs. Our laboratory and others have reported that the classical PKC isozyme, PKCαnegatively regulates proliferation and tumorigenesis in the intestinal epithelium. Our laboratory has further determined that PKCα signaling induces a program of cell cycle withdrawal in intestinal epithelial cells that involves downregulation of the pro-proliferative proteins, cyclin D1 and Id1, and upregulation of the cyclin dependent kinase (CDK) inhibitor, p21^Cip1. Unexpectedly, …