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Full-Text Articles in Biochemistry
Multidrug Resistance Regulators Mara, Soxs, Rob, And Rama Repress Flagellar Gene Expression And Motility In Salmonella Enterica Serovar Typhimurium, Srinivas Thota, Lon Chubiz
Multidrug Resistance Regulators Mara, Soxs, Rob, And Rama Repress Flagellar Gene Expression And Motility In Salmonella Enterica Serovar Typhimurium, Srinivas Thota, Lon Chubiz
Biology Department Faculty Works
Production of flagella is costly and subject to global multilayered regulation, which is reflected in the hierarchical control of flagellar production in many bacterial species. For Salmonella enterica serovar Typhimurium and its relatives, global regulation of flagellar production primarily occurs through the control of flhDC transcription and mRNA translation. In this study, the roles of the homologous multidrug resistance regulators MarA, SoxS, Rob, and RamA (constituting the mar-sox-rob regulon in S. Typhimurium) in regulating flagellar gene expression were explored. Each of these regulators was found to inhibit flagellar gene expression, production of flagella, and motility. To different degrees, repression via …
Dual Activities Of Plant Cgmp-Dependent Protein Kinase And Its Roles In Gibberellin Signaling And Salt Stress., Qingwen Shen, Xinqiao Zhan, Pei Yang, Jing Li, Jie Chen, Bing Tang, Xuemin Wang, Xuemin Wang, Yueyun Hong
Dual Activities Of Plant Cgmp-Dependent Protein Kinase And Its Roles In Gibberellin Signaling And Salt Stress., Qingwen Shen, Xinqiao Zhan, Pei Yang, Jing Li, Jie Chen, Bing Tang, Xuemin Wang, Xuemin Wang, Yueyun Hong
Biology Department Faculty Works
Cyclic GMP (cGMP) is an important regulator in eukaryotes, and cGMP-dependent protein kinase (PKG) plays a key role in perceiving cellular cGMP in diverse physiological processes in animals. However, the molecular identity, property, and function of PKG in plants remain elusive. In this study, we have identified PKG from plants and characterized its role in mediating the gibberellin (GA) response in rice (Oryza sativa). PKGs from plants are structurally unique with an additional type 2C protein phosphatase domain. Rice PKG possesses both protein kinase and phosphatase activities, and cGMP stimulates its kinase activity but inhibits its phosphatase activity. One of …
Interaction And Regulation Between Lipid Mediator Phosphatidic Acid And Circadian Clock Regulators, Sang-Chul Kim, Sang-Chul Kim, Dmitri Nusinow, Maria Sorkin, Maria Sorkin, Jose Pruneda-Paz, Xuemin Wang, Xuemin Wang
Interaction And Regulation Between Lipid Mediator Phosphatidic Acid And Circadian Clock Regulators, Sang-Chul Kim, Sang-Chul Kim, Dmitri Nusinow, Maria Sorkin, Maria Sorkin, Jose Pruneda-Paz, Xuemin Wang, Xuemin Wang
Biology Department Faculty Works
Circadian clocks play important roles in regulating cellular metabolism, but the reciprocal effect that metabolism has on the clock is largely unknown in plants. Here we show that the central glycerolipid metabolite and lipid mediator phosphatidic acid (PA) interacts with and modulates the function of the core clock regulators LATE ELONGATED HYPOCOTYL (LHY) and CIRCADIAN CLOCK ASSOCIATED1 (CCA1) in Arabidopsis thaliana. PA reduced the ability of LHY and CCA1 to bind the promoter of their target gene TIMING OF CAB EXPRESSION1. Increased PA accumulation and inhibition of PA-producing enzymes had opposite effects on circadian clock outputs. Diurnal change in levels …
Growth Trade-Offs Accompany The Emergence Of Glycolytic Metabolism In Shewanella Oneidensis Mr-1, Lon Chubiz, Christopher Marx
Growth Trade-Offs Accompany The Emergence Of Glycolytic Metabolism In Shewanella Oneidensis Mr-1, Lon Chubiz, Christopher Marx
Biology Department Faculty Works
Bacteria increase their metabolic capacity via the acquisition of genetic material or by the mutation of genes already present in the genome. Here, we explore the mechanisms and trade-offs involved when Shewanella oneidensis, a bacterium that typically consumes small organic and amino acids, rapidly evolves to expand its metabolic capacity to catabolize glucose after a short period of adaptation to a glucose-rich environment. Using whole-genome sequencing and genetic approaches, we discovered that deletions in a region including the transcriptional repressor (nagR) that regulates the expression of genes associated with catabolism of N-acetylglucosamine are the common basis for evolved glucose metabolism …
Phospholipase Dζ Enhances Diacylglycerol Flux Into Triacylglycerol, Wenyu Yang, Geliang Wang, Jia Li, Philip Bates, Xuemin Wang, Douglas Allen
Phospholipase Dζ Enhances Diacylglycerol Flux Into Triacylglycerol, Wenyu Yang, Geliang Wang, Jia Li, Philip Bates, Xuemin Wang, Douglas Allen
Biology Department Faculty Works
Plant seeds are the primary source of triacylglycerols (TAG) for food, feed, fuel, and industrial applications. As TAG is produced from diacylglycerol (DAG), successful engineering strategies to enhance TAG levels have focused on the conversion of DAG to TAG. However, the production of TAG can be limited by flux through the enzymatic reactions that supply DAG. In this study, two Arabidopsis phospholipase Dζ genes (AtPLDζ1 and AtPLDζ2) were coexpressed in Camelina sativa to test whether the conversion of phosphatidylcholine to DAG impacts TAG levels in seeds. The resulting transgenic plants produced 2% to 3% more TAG as a component of …
Non-Specific Phospholipase C1 Affects Silicon Distribution And Mechanical Strength In Stem Nodes Of Rice, Huasheng Cao, Lin Zhuo, Yuan Su, Linxiao Sun, Xuemin Wang
Non-Specific Phospholipase C1 Affects Silicon Distribution And Mechanical Strength In Stem Nodes Of Rice, Huasheng Cao, Lin Zhuo, Yuan Su, Linxiao Sun, Xuemin Wang
Biology Department Faculty Works
Silicon, the second abundant element in the crust, is beneficial for plant growth, mechanical strength, and stress responses. Here we show that manipulation of the non‐specific phospholipase C1, NPC1, alters silicon content in nodes and husks of rice (Oryza sativa). Silicon content in NPC1‐overexpressing (OE) plants was decreased in nodes but increased in husks compared to wild‐type, whereas RNAi suppression of NPC1 resulted in the opposite changes to those of NPC1‐OE plants. NPC1 from rice hydrolyzed phospholipids and galactolipids to generate diacylglycerol that can be phosphorylated to phosphatidic acid. Phosphatidic acid interacts with Lsi6, a silicon transporter that is expressed …
Membrane Glycerolipidome Of Soybean Root Hairs And Its Response To Nitrogen And Phosphate Availability, Fang Wei, Brian Fanella, Liang Guo, Xuemin Wang
Membrane Glycerolipidome Of Soybean Root Hairs And Its Response To Nitrogen And Phosphate Availability, Fang Wei, Brian Fanella, Liang Guo, Xuemin Wang
Biology Department Faculty Works
Root hairs are tubular extensions of specific root epidermal cells important in plant nutrition and water absorption. To determine membrane glycerolipids in root hairs and roots may differ, as well as their respective response to nutrient availability, this study analyzed the membrane glycerolipid species in soybean root hairs and in roots stripped of root hairs, and their response to nitrogen (N) and phosphate (Pi) supplementation. The ratio of phospholipids to galactolipids was 1.5 fold higher in root hairs than in stripped roots. Under Pi deficiency, the ratio of phospholipids to galactolipids in stripped roots decreased with the greatest decrease found …
[Accepted Article Manuscript Version (Postprint)] Auxin Input Pathway Disruptions Are Mitigated By Changes In Auxin Biosynthetic Gene Expression In Arabidopsis, Gretchen Spiess, Amanda Hausman, Peng Yu, Jerry Cohen, Rebekah Rampey, Bethany Zolman
[Accepted Article Manuscript Version (Postprint)] Auxin Input Pathway Disruptions Are Mitigated By Changes In Auxin Biosynthetic Gene Expression In Arabidopsis, Gretchen Spiess, Amanda Hausman, Peng Yu, Jerry Cohen, Rebekah Rampey, Bethany Zolman
Biology Department Faculty Works
Auxin is a phytohormone involved in cell elongation and division. Levels of indole-3-acetic acid (IAA), the primary auxin, are tightly regulated through biosynthesis, degradation, sequestration, and transport. IAA is sequestered in reversible processes by adding amino acids, polyol or simple alcohols, or sugars, forming IAA conjugates, or through a two-carbon elongation forming indole-3-butyric acid. These sequestered forms of IAA alter hormone activity. To gain a better understanding of how auxin homeostasis is maintained, we have generated Arabidopsis (Arabidopsis thaliana) mutants that combine disruptions in the pathways, converting IAA conjugates and indole-3-butyric acid to free IAA. These mutants show phenotypes indicative …
Patatin-Related Phospholipase Pplaiiiδ Increases Seed Oil Content With Long-Chain Fatty Acids In Arabidopsis, Maoyin Li, Sung Bahn, Chuchuan Fan, Jia Li, Tien Phan, Michael Ortiz, Mary Roth, Ruth Welti, Jan Jaworski, Xuemin Wang
Patatin-Related Phospholipase Pplaiiiδ Increases Seed Oil Content With Long-Chain Fatty Acids In Arabidopsis, Maoyin Li, Sung Bahn, Chuchuan Fan, Jia Li, Tien Phan, Michael Ortiz, Mary Roth, Ruth Welti, Jan Jaworski, Xuemin Wang
Biology Department Faculty Works
The release of fatty acids from membrane lipids has been implicated in various metabolic and physiological processes, but in many cases, the enzymes involved and their functions in plants remain unclear. Patatin-related phospholipase As (pPLAs) constitute a major family of acyl-hydrolyzing enzymes in plants. Here, we show that pPLAIIId promotes the production of triacylglycerols with 20- and 22-carbon fatty acids in Arabidopsis (Arabidopsis thaliana). Of the four pPLAIIIs (a, b, g, d), only pPLAIIId gene knockout results in a decrease in seed oil content, and pPLAIIId is most highly expressed in developing embryos. The overexpression of pPLAIIId increases the content …
[Accepted Article Manuscript Version (Postprint)] Plant Peroxisomes: Biogenesis And Function, Jianping Hu, Alison Baker, Bonnie Bartel, Nicole Linka, Robert Mullen, Sigrun Reumann, Bethany Zolman
[Accepted Article Manuscript Version (Postprint)] Plant Peroxisomes: Biogenesis And Function, Jianping Hu, Alison Baker, Bonnie Bartel, Nicole Linka, Robert Mullen, Sigrun Reumann, Bethany Zolman
Biology Department Faculty Works
Peroxisomes are eukaryotic organelles that are highly dynamic both in morphology and metabolism. Plant peroxisomes are involved in numerous processes, including primary and secondary metabolism, development, and responses to abiotic and biotic stresses. Considerable progress has been made in the identification of factors involved in peroxisomal biogenesis, revealing mechanisms that are both shared with and diverged from non-plant systems. Furthermore, recent advances have begun to reveal an unexpectedly large plant peroxisomal proteome and have increased our understanding of metabolic pathways in peroxisomes. Coordination of the biosynthesis, import, biochemical activity, and degradation of peroxisomal proteins allows for highly dynamic responses of …
Role Of The Mar-Sox-Rob Regulon In Regulating Outer Membrane Porin Expression, Lon Chubiz, Christopher Rao
Role Of The Mar-Sox-Rob Regulon In Regulating Outer Membrane Porin Expression, Lon Chubiz, Christopher Rao
Biology Department Faculty Works
Multiple factors control the expression of the outer membrane porins OmpF and OmpC in Escherichia coli. In this work, we investigated the role of the mar-sox-rob regulon in regulating outer membrane porin expression in response to salicylate. We provide both genetic and physiological evidence that MarA and Rob can independently activate micF transcription in response to salicylate, leading to reduced OmpF expression. MarA was also found to repress OmpF expression through a MicF-independent pathway. In the case of OmpC, we found that its transcription was moderately increased in response to salicylate. However, this increase was independent of MarA and Rob. …
[Accepted Article Manuscript Version (Postprint)] Pex5 Mutants That Differentially Disrupt Pts1 And Pts2 Peroxisomal Matrix Protein Import In Arabidopsis, Bibi Khan, Bethany Zolman
[Accepted Article Manuscript Version (Postprint)] Pex5 Mutants That Differentially Disrupt Pts1 And Pts2 Peroxisomal Matrix Protein Import In Arabidopsis, Bibi Khan, Bethany Zolman
Biology Department Faculty Works
PEX5 and PEX7 are receptors required for the import of peroxisome-bound proteins containing one of two peroxisomal targeting signals (PTS1 or PTS2). To better understand the role of PEX5 in plant peroxisomal import, we characterized the Arabidopsis (Arabidopsis thaliana) pex5-10 mutant, which has a T-DNA insertion in exon 5 of the PEX5 gene. Sequencing results revealed that exon 5, along with the T-DNA, is removed in this mutant, resulting in a truncated pex5 protein. The pex5-10 mutant has germination defects and is completely dependent on exogenous Suc for early seedling establishment, based on poor utilization of seed-storage fatty acids. This …
Aromatic Acid Metabolites Of Escherichia Coli K-12 Can Induce The Marrab Operon, Lon Chubiz, Christopher Rao
Aromatic Acid Metabolites Of Escherichia Coli K-12 Can Induce The Marrab Operon, Lon Chubiz, Christopher Rao
Biology Department Faculty Works
MarR is a key regulator of the marRAB operon involved in antibiotic resistance and solvent stress tolerance in Escherichia coli. We show that two metabolic intermediates, 2,3-dihydroxybenzoate and anthranilate, involved in enterobactin and tryptophan biosynthesis, respectively, can activate marRAB transcription. We also found that a third intermediate involved in ubiquinone biosynthesis, 4-hydroxybenzoate, activates marRAB transcription in the absence of TolC. Of the three, however, only 2,3-dihydroxybenzoate directly binds MarR and affects its activity.
[Accepted Article Manuscript Version (Postprint)] Identification And Functional Characterization Of Arabidopsis Peroxin4 And The Interacting Protein Peroxin22, Bethany Zolman, Melanie Monroe-Augustus, Illeana Silva, Bonnie Bartel
[Accepted Article Manuscript Version (Postprint)] Identification And Functional Characterization Of Arabidopsis Peroxin4 And The Interacting Protein Peroxin22, Bethany Zolman, Melanie Monroe-Augustus, Illeana Silva, Bonnie Bartel
Biology Department Faculty Works
Peroxins are genetically defined as proteins necessary for peroxisome biogenesis. By screening for reduced response to indole-3-butyric acid, which is metabolized to active auxin in peroxisomes, we isolated an Arabidopsis thaliana peroxin4 (pex4) mutant. This mutant displays sucrose-dependent seedling development and reduced lateral root production, characteristics of plant peroxisome malfunction. We used yeast two-hybrid analysis to determine that PEX4, an apparent ubiquitinconjugating enzyme, interacts with a previously unidentified Arabidopsis protein, PEX22. A pex4 pex22 double mutant enhanced pex4 defects, confirming that PEX22 is a peroxin. Expression of both Arabidopsis genes together complemented yeast pex4 or pex22 mutant defects, whereas expression …
Metabolic Responses Of Shorebird Chicks To Cold Stress: Hysteresis Of Cooling And Warming Phases, Robert Ricklefs, Joseph Williams
Metabolic Responses Of Shorebird Chicks To Cold Stress: Hysteresis Of Cooling And Warming Phases, Robert Ricklefs, Joseph Williams
Biology Department Faculty Works
We developed a protocol for determining the maximum rate of oxygen consumption of shorebird chicks (Scolopacidae and Charadriidae) in response to cold challenge. We first subjected the chicks to gradually decreasing temperatures until their metabolism peaked and began to decrease. We ended the cooling phase of a trial when a chick’s body temperature Tb had declined typically to 32–34°C. After this point, we gradually increased the temperature in the metabolism chamber until normal Tb values and thermoneutral resting metabolism were restored. We refer to this cycle as the down–up (DU) protocol. We estimated instantaneous oxygen consumption (V . O∑) using …
The Rna-Binding Site Of Bacteriophage Qβ Coat Protein, Francis Lim, Marc Spingola, David Peabody
The Rna-Binding Site Of Bacteriophage Qβ Coat Protein, Francis Lim, Marc Spingola, David Peabody
Biology Department Faculty Works
The coat proteins of the RNA bacteriophages Qβ and MS2 are specific RNA binding proteins. Although they possess common tertiary structures, they bind different RNA stem loops and thus provide useful models of specific protein-RNA recognition. Although the RNA-binding site of MS2 coat protein has been extensively characterized previously, little is known about Qβ. Here we describe the isolation of mutants that define the RNA-binding site of Qβ coat protein, showing that, as with MS2, it resides on the surface of a large β-sheet. Mutations are also described that convert Qβ coat protein to the RNA binding specificity of MS2. …
Altering The Rna Binding Specificity Of A Translational Repressor, F Lim, Marc Spingola, D Peabody
Altering The Rna Binding Specificity Of A Translational Repressor, F Lim, Marc Spingola, D Peabody
Biology Department Faculty Works
The coat proteins of RNA phages MS2 and GA are specific RNA-binding proteins which function to encapsidate viral RNA and to translationally repress synthesis of the viral replicase. The two proteins have highly homologous amino acid sequences, yet they show different RNA binding specificities, recognizing RNA stem-loop structures which differ primarily in the nucleotide sequences of their loops. We sought to convert MS2 coat protein to the RNA binding specificity of GA through the introduction of GA-like amino acid substitutions into the MS2 coat protein RNA-binding site. The effects of the mutations were determined by measuring the affinity of the …