Biochemistry Commons^™

[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 …

Physical Interaction Between Vivid And White Collar Complex Regulates Photoadaptation In Neurospora, Chen-Hui H. Chen, Bradley S. Demay, Amy S. Gladfelter, Jay Dunlap, Jennifer J. Loros

Dartmouth Scholarship

Photoadaptation, the ability to attenuate a light response on prolonged light exposure while remaining sensitive to escalating changes in light intensity, is essential for organisms to decipher time information appropriately, yet the underlying molecular mechanisms are poorly understood. In Neurospora crassa, VIVID (VVD), a small LOV domain containing blue-light photoreceptor protein, affects photoadaptation for most if not all light-responsive genes. We report that there is a physical interaction between VVD and the white collar complex (WCC), the primary blue-light photoreceptor and the transcription factor complex that initiates light-regulated transcriptional responses in Neurospora. Using two previously characterized VVD mutants, we show …

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.

Selection For Non-Amyloidogenic Mutants Of Islet Amyloid Polypeptide (Iapp) Identifies An Extended Region For Amyloidogenicity, Ayano Fox, Thibaut Snollaerts, Camille Errecart Casanova, Anastasia Calciano, Luiza A. Nogaj, David A. Moffet

Chemistry and Biochemistry Faculty Works

The aggregation of the 37-residue polypeptide IAPP, as either insoluble amyloid or as small oligomers, appears to play a direct role in the death of pancreatic β-islet cells in type II diabetes. While IAPP has been known to be the primary component of type II diabetes amyloid, the molecular interactions responsible for this aggregation have not been identified. To identify the aggregation-prone region(s), we constructed a library of randomly generated point mutants of IAPP. This mutant IAPP library was expressed in E. coli as genetic fusions to the reporter protein enhanced green fluorescent protein (EGFP). Because IAPP aggregates rapidly, both …

Preeclampsia, Autoimmunity And The At1 Receptor, Roxanna A. Irani

Dissertations & Theses (Open Access)

Preeclampsia (PE) is a disease of late pregnancy characterized by maternal hypertension and proteinuria. It is associated with preterm delivery and significant perinatal morbidity and mortality. Despite affecting ~7% of first pregnancies, there is no effective screening method to identify women at risk, nor is there a definitive treatment other than delivery of the baby and placenta. Though the pathogenesis of PE remains unclear, an imbalance in the renin-angiotensin and immune systems are thought to be major contributors. Bridging these two concepts, it has recently been shown that women with PE harbor specific autoantibodies: the angiotensin II type 1 receptor …

Antimicrobial And Antioxidant Activities Of Essential Oil And Methanol Extract Of Jasminum Sambac From Djibouti, Fatou Abdoul-Latif, Prosper Edou, François Eba, Nabil Mohamed, Adwa Ali, Samatar Djama, Louis-Clément Obame, Mamoudou Hama Dicko

Pr. Mamoudou H. DICKO, PhD

The essential oil of jasminum sambac from Djibouti was subjected to screening for their possible antioxidant activity by two complementary test systems, namely DPPH free radical scavenging and beta-carotene-linoleic acid assays. Butylated hydroxytoluene (BHT) was used as positive control in both test systems. In the DPPH test system, the IC50 value of essential oil and methanol extract were respectively 7.43 and 2.30 μg/ml. In the beta-carotene-linoleic acid system, oxidation was effectively inhibited by Jasminum sambac, the RAA value of essential oil and methanol extract were respectively 96.6 and 93.9%. When compared to BHT, the essential oil and methanol extract had …

Maternal Consumption Of Canola Oil Suppressed Mammary Gland Tumorigenesis In C3(1) Tag Mice Offspring, Gabriela Ion, Juliana A. Akinsete, W. Elaine Hardman

Biochemistry and Microbiology

Background: Maternal consumption of a diet high in omega 6 polyunsaturated fats (n-6 PUFA) has been shown to increase risk whereas a diet high in omega 3 polyunsaturated fats (n-3 PUFA) from fish oil has been shown to decrease risk for mammary gland cancer in female offspring of rats. The aim of this study was to determine whether increasing n-3 PUFA and reducing n-6 PUFA by using canola oil instead of corn oil in the maternal diet might reduce the risk for breast cancer in female offspring.

Methods: Female SV 129 mice were divided into two groups and placed on …

Nip/Duoxa Is Essential For Drosophila Embryonic Development And Regulates Oxidative Stress Response., Xiaojun Xie, Jack Hu, Xiping Liu, Hanjuan Qin, Anthony Percival-Smith, Yong Rao, Shawn S C Li

Biochemistry Publications

NIP/DuoxA, originally cloned as a protein capable of binding to the cell fate determinant Numb in Drosophila, was recently identified as a modulator of reactive oxygen species (ROS) production in mammalian systems. Despite biochemical and cellular studies that link NIP/DuoxA to the generation of ROS through the dual oxidase (Duox) enzyme, the in vivo function of NIP/DuoxA has not been characterized to date. Here we report a genetic and functional characterization of nip in Drosophila melanogaster. We show that nip is essential for Drosophila development as nip null mutants die at the 1(st) larval instar. Expression of UAS-nip, but not …

Plasticity Of Acquired Secondary Metabolites In Clathria Prolifera (Demospongia: Poecilosclerida): Putative Photoprotective Role Of Carotenoids In A Temperate Intertidal Sponge, Jonathan D. Dattelbaum, Drew Sieg, Malcolm Hill, Chris M. Manieri, Giles Thomson

Chemistry Faculty Publications

Several marine sponges sequester high concentrations of carotenoids in their tissues. The diversity of carotenoid compounds has been described in detail for a handful of species, but to date, little attention has been paid to natural variability in the concentration and constituency of carotenoid pools. Also lacking are experimental tests of some of the proposed adaptive benefits of carotenoids to the sponge. To address some of these deficits in our understanding of sponge ecology, we used a combination of analytic chemistry, field surveys, and manipulative experiments to determine what function these compounds might play. Attention was focused on the common, …

Structural Investigation Of Atp-Utilizing Enzymes: Structures Involved In H+ Homeostasis And The Proliferation Of Hormone-Dependent Cancers, Zacariah Louis Hildenbrand

Open Access Theses & Dissertations

ATP is a multifunctional nucleotide considered to be the "molecular unit of currency" of intracellular energy transfer. ATP is utilized ubiquitously for the transport of chemical energy within the cell in addition to acting as a substrate in the regulation of many metabolic and signaling transduction pathways such as kinase-mediated signaling cascades. Interestingly, the functional mechanisms of many enzymes require the binding of ATP to trigger key structural and conformational changes that ultimately result in enzyme-directed catalysis. Two of the most omnipresent ATPases within the cell include the V-ATPase rotary proton pump and the Hsp90 protein-folding chaperone. Structural and biochemical …