Physiology Commons^™

Beta-Lysine Discrimination By Lysyl-Trna Synthetase, Marla S. Gilreath, Hervé Roy, Tammy J. Bullwinkle, Assaf Katz, Michael Ibba, William Wiley Navarre

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Elongation factor P is modified with (R)‐β‐lysine by the lysyl‐tRNA synthetase (LysRS) paralog PoxA. PoxA specificity is orthogonal to LysRS, despite their high similarity. To investigate α‐ and β‐lysine recognition by LysRS and PoxA, amino acid replacements were made in the LysRS active site guided by the PoxA structure. A233S LysRS behaved as wild type with α‐lysine, while the G469A and A233S/G469A variants decreased stable α‐lysyl‐adenylate formation. A233S LysRS recognized β‐lysine better than wildtype, suggesting a role for this residue in discriminating α‐ and β‐amino acids. Both enantiomers of β‐lysine were substrates for tRNA aminoacylation by LysRS, which, together with …

The Trna Synthetase Paralog Poxa Modifies Elongation Factor-P With (R)-Β-Lysine, Hervé Roy, S. Betty Zou, Tammy J. Bullwinkle, Benjamin S. Wolfe, Marla S. Gilreath, Craig J. Forsyth, William Wiley Navarre, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The lysyl-tRNA synthetase paralog PoxA modifies elongation factor P (EF-P) with α-lysine at low efficiency. Cell-free extracts containing non–α-lysine substrates of PoxA modified EF-P with a change in mass consistent with addition of β-lysine, a substrate also predicted by genomic analyses. EF-P was efficiently functionally modified with (R)-β-lysine but not (S)-β-lysine or genetically encoded α-amino acids, indicating that PoxA has evolved an activity orthogonal to that of the canonical aminoacyl-tRNA synthetases.

Interspecies Comparison Of Αii-Spectrin Abundance Between Chinook Salmon And Steelhead, Brielle D. Kemis, Ann L. Miracle, Katie A. Wagner, Christa M. Woodley

STAR Program Research Presentations

Salmonids, such as Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss), are a staple economic, recreational, tribal, and environmental resource, yet many populations are unsustainable. This study was part of a broad scale effort to monitor the impact of downstream migration obstacles on juvenile salmonid health and survival, which is an essential step towards increasing Smolt-to-Adult Return ratios (SARs). The objective of this study was to determine if juvenile Chinook salmon and steelhead exhibit differing quantities of alphaII-Spectrin Breakdown Products (SBDPs) over two consecutive spring migration periods, indicative of neurogenesis rate and/or biological response to head …

Regulation Of Endothelial Nitric Oxide Synthase In Pulmonary Myofibroblasts, Jonathan David Faughn

Masters Theses & Specialist Projects

Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease leading to decreased lung volume and eventual respiratory failure. At present, the median post-diagnosis lifespan is between three and six years. Myofibroblasts are collagen-secreting cells essential for wound healing, but also implicated in the fibroproliferation and extra cellular matrix deposition commonly seen in IPF. The nitric oxide (NO) signaling pathway is implicated in protomyofibroblast to myofibroblast transition and regulation. Previous work has shown that in pulmonary myofibroblasts, endothelial nitric oxide synthase (eNOS) is the primary NOS isoform expressed. The current study used cultured rat pulmonary myofibroblasts between passages two and five …

Aberrant Promoter Cpg Methylation Is A Mechanism For Impaired Phd3 Expression In A Diverse Set Of Malignant Cells., Trenton L. Place, Matthew P. Fitzgerald, Sujatha Venkataraman, Sabine U. Vorrink, Adam J. Case, Melissa L.T. Teoh, Frederick E. Domann

Journal Articles: Cellular & Integrative Physiology

BACKGROUND: The prolyl-hydroxylase domain family of enzymes (PHD1-3) plays an important role in the cellular response to hypoxia by negatively regulating HIF-α proteins. Disruption of this process can lead to up-regulation of factors that promote tumorigenesis. We observed decreased basal expression of PHD3 in prostate cancer tissue and tumor cell lines representing diverse tissues of origin. Furthermore, some cancer lines displayed a failure of PHD3 mRNA induction when introduced to a hypoxic environment. This study explores the mechanism by which malignancies neither basally express PHD3 nor induce PHD3 under hypoxic conditions.

METHODOLOGY/PRINCIPAL FINDINGS: Using bisulfite sequencing and methylated DNA enrichment …

Dose-Dependent Thresholds Of 10-Ns Electric Pulse Induced Plasma Membrane Disruption And Cytotoxicity In Multiple Cell Lines, Bennett L. Ibey, Caleb C. Roth, Andrei G. Pakhomov, Joshua A. Bernhard, Gerald J. Wilmink, Olga N. Pakhomova

Bioelectrics Publications

In this study, we determined the LD50 (50% lethal dose) for cell death, and the ED50 (50% of cell population staining positive) for propidium (Pr) iodide uptake, and phosphatidylserine (PS) externalization for several commonly studied cell lines (HeLa, Jurkat, U937, CHO-K1, and GH3) exposed to 10-ns electric pulses (EP). We found that the LD50 varied substantially across the cell lines studied, increasing from 51 J/g for Jurkat to 1861 J/g for HeLa. PS externalized at doses equal or lower than that required for death in all cell lines ranging from 51 J/g in Jurkat, to 199 J/g in CHO-K1. Pr …

Genetic And Maternal Effects On Valproic Acid Teratogenesis In C57bl/6j And Dba/2j Mice, Chris Downing, Jami Biers, Colin Larson, Alexi Kimball, Hali Wright, Takamasa Ishii, David Gilliam, Thomas Johnson

SPS Faculty Publications

Valproic acid (VPA) is used worldwide to treat epilepsy, migraine headaches and bipolar disorder. However, VPA is teratogenic and in utero exposure can lead to congenital malformations. Using inbred C57BL/6J (B6) and DBA/2J (D2) mice, we asked whether genetic variation could play a role in susceptibility to VPA teratogenesis. While B6 fetuses were more susceptible than D2 fetuses to digit and vertebral malformations, D2 fetuses were more susceptible to rib malformations. In a reciprocal cross between B6 and D2, genetically identical F1 mice carried in a B6 mother had a greater percentage of vertebral malformations following prenatal VPA exposure than …

Human Chondrosarcoma Cells Acquire An Epithelial-Like Gene Expression Pattern Via An Epigenetic Switch: Evidence For Mesenchymal-Epithelial Transition During Sarcomagenesis., Matthew P. Fitzgerald, Francoise Gourronc, Melissa L.T. Teoh, Matthew J. Provenzano, Adam J. Case, James A. Martin, Frederick E. Domann

Journal Articles: Cellular & Integrative Physiology

Chondrocytes are mesenchymally derived cells that reportedly acquire some epithelial characteristics; however, whether this is a progression through a mesenchymal to epithelial transition (MET) during chondrosarcoma development is still a matter of investigation. We observed that chondrosarcoma cells acquired the expression of four epithelial markers, E-cadherin,desmocollin 3, maspin, and 14-3-3σ, all of which are governed epigenetically through cytosine methylation. Indeed, loss of cytosine methylation was tightly associated with acquired expression of both maspin and 14-3-3σ in chondrosarcomas. In contrast, chondrocyte cells were negative for maspin and 14-3-3σ and displayed nearly complete DNA methylation. Robust activation of these genes was also …

Dog Models Of Naturally Occurring Cancer, Donna O. Mccarthy

College of Nursing Faculty Research and Publications

Studies using dogs provide an ideal solution to the gap in animal models for natural disease and translational medicine. This is evidenced by approximately 400 inherited disorders being characterized in domesticated dogs, most of which are relevant to humans. There are several hundred isolated populations of dogs (breeds) and each has a vastly reduced genetic variation compared with humans; this simplifies disease mapping and pharmacogenomics. Dogs age five- to eight-fold faster than do humans, share environments with their owners, are usually kept until old age and receive a high level of health care. Farseeing investigators recognized this potential and, over …