Biochemistry, Biophysics, and Structural Biology Commons^™

Toxoplasma Gondii Requires Its Plant-Like Heme Biosynthesis Pathway For Infection, Amy Bergmann, Kathleen Floyd, Melanie Key, Carly Dameron, Kerrick C. Rees, L. Brock Thornton, Daniel C. Whitehead, Iqbal Hamza, Zhicheng Dou

Publications

Heme, an iron-containing organic ring, is essential for virtually all living organisms by serving as a prosthetic group in proteins that function in diverse cellular activities ranging from diatomic gas transport and sensing, to mitochondrial respiration, to detoxification. Cellular heme levels in microbial pathogens can be a composite of endogenous de novo synthesis or exogenous uptake of heme or heme synthesis intermediates. Intracellular pathogenic microbes switch routes for heme supply when heme availability fluctuates in their replicative environment throughout infection. Here, we show that Toxoplasma gondii, an obligate intracellular human pathogen, encodes a functional heme biosynthesis pathway. A chloroplast-derived …

Trait Differentiation And Modular Toxin Expression In Palm-Pitvipers, Andrew J. Mason, Mark J. Margres, Jason L. Strickland, Darin R. Rokyta, Mahmood Sasa, Christopher L. Parkinson

Publications

Background

Modularity is the tendency for systems to organize into semi-independent units and can be a key to the evolution and diversification of complex biological systems. Snake venoms are highly variable modular systems that exhibit extreme diversification even across very short time scales. One well-studied venom phenotype dichotomy is a trade-off between neurotoxicity versus hemotoxicity that occurs through the high expression of a heterodimeric neurotoxic phospholipase A2 (PLA2) or snake venom metalloproteinases (SVMPs). We tested whether the variation in these venom phenotypes could occur via variation in regulatory sub-modules through comparative venom gland transcriptomics of representative Black-Speckled Palm-Pitvipers (Bothriechis …

Comparison Study Of Mold Growth Resistance Of Plastic Based Material Flooring (Pbm Flooring) And Ceramic Tile Flooring, Jyothi Rangineni, Jeremy Tzeng

Publications

Clemson University Department of Biological Sciences and Tile Council of North America Product Performance Testing Laboratory evaluated whether ceramic tile and Plastic Based Material (PBM¹) flooring support mold growth when exposed to fungal spores.

Mold grows in moisture-rich environments and requires only minimal sources of nutrition to support growth. It has long been identified to cause damage to buildings and construction materials and its presence in buildings has been connected to many major health concerns with various studies and reviews published on this matter.²

The method used to evaluate mold growth was ASTM G21-96 (2015).³ This …

Discovery Of Genomic Variations By Whole-Genome Resequencing Of The North American Araucana Chicken, Rooksana E. Noorai, Vijay Shankar, Nowlan H. Freese, Christopher M. Gregorski, Susan C. Chapman

Publications

Gallus gallus (chicken) is phenotypically diverse, with over 60 recognized breeds, among the myriad species within the Aves lineage. Domestic chickens have been under artificial selection by humans for thousands of years for agricultural purposes. The North American Araucana (NAA) breed arose as a cross between the Chilean “Collonocas” that laid blue eggs and was rumpless and the “Quetros” that had unusual tufts but with tail. NAAs were introduced from South America in the 1940s and have been kept as show birds by enthusiasts since then due to several distinctive traits: laying eggs with blue eggshells, characteristic ear-tufts, a pea …

Glucose Signaling Is Important For Nutrient Adaptation During Differentiation Of Pleomorphic African Trypanosomes, Yijian Qiu, Jillian E. Milanes, Jessica A. Jones, Rooksana E. Noorai, Vijay Shankar, James C. Morris

Publications

The African trypanosome has evolved mechanisms to adapt to changes in nutrient availability that occur during its life cycle. During transition from mammalian blood to insect vector gut, parasites experience a rapid reduction in environmental glucose. Here we describe how pleomorphic parasites respond to glucose depletion with a focus on parasite changes in energy metabolism and growth. Long slender bloodstream form parasites were rapidly killed as glucose concentrations fell, while short stumpy bloodstream form parasites persisted to differentiate into the insect-stage procyclic form parasite. The rate of differentiation was lower than that triggered by other cues but reached physiological rates …

Homologous Recombination In Protozoan Parasites And Recombinase Inhibitors, Andrew A. Kelso, Sarah M. Waldvogel, Adam J. Luthman, Michael G. Sehorn

Publications

Homologous recombination (HR) is a DNA double-strand break (DSB) repair pathway that utilizes a homologous template to fully repair the damaged DNA. HR is critical to maintain genome stability and to ensure genetic diversity during meiosis. A specialized class of enzymes known as recombinases facilitate the exchange of genetic information between sister chromatids or homologous chromosomes with the help of numerous protein accessory factors. The majority of the HR machinery is highly conserved among eukaryotes. In many protozoan parasites, HR is an essential DSB repair pathway that allows these organisms to adapt to environmental conditions and evade host immune systems …

Annotation Of The Nuclear Receptors In An Estuarine Fish Species, Fundulus Heteroclitus, William S. Baldwin

Publications

The nuclear receptors (NRs) are ligand-dependent transcription factors that respond to various internal as well as external cues such as nutrients, pheromones, and steroid hormones that play crucial roles in regulation and maintenance of homeostasis and orchestrating the physiological and stress responses of an organism. We annotated the Fundulus heteroclitus (mummichog; Atlantic killifish) nuclear receptors. Mummichog are a non-migratory, estuarine fish with a limited home range often used in environmental research as a field model for studying ecological and evolutionary responses to variable environmental conditions such as salinity, oxygen, temperature, pH, and toxic compounds because of their hardiness. F. heteroclitus …

Correlated Mutation In The Evolution Of Catalysis In Uracil Dna Glycosylase Superfamily, Bo Xia, Yingling Liu, Jose Guevara, Jing Li, Celeste Jilich, Ye Yang, Liangjiang Wang, Brian N. Dominy, Weiguo Cao

Publications

Enzymes in Uracil DNA glycosylase (UDG) superfamily are essential for the removal of uracil. Family 4 UDGa is a robust uracil DNA glycosylase that only acts on double-stranded and single-stranded uracil-containing DNA. Based on mutational, kinetic and modeling analyses, a catalytic mechanism involving leaving group stabilization by H155 in motif 2 and water coordination by N89 in motif 3 is proposed. Mutual Information analysis identifies a complexed correlated mutation network including a strong correlation in the EG doublet in motif 1 of family 4 UDGa and in the QD doublet in motif 1 of family 1 UNG. Conversion of EG …

Smug2 Dna Glycosylase From Pedobacter Heparinus As A New Subfamily In Udg Superfamily, Panjiao Pang, Ye Yang, Jing Li, Zhong Wang, Weiguo Cao, Wei Xie

Publications

Base deamination is a common type of DNA damage that occurs in all organisms. DNA repair mechanisms are essential to maintain genome integrity, in which the base excision repair (BER) pathway plays a major role in the removal of base damage. In the BER pathway, the uracil DNA glycosylase superfamily is responsible for excising the deaminated bases from DNA and generates apurinic/apyrimidinic (AP) sites. Using bioinformatics tools, we identified a family 3 SMUG1-like DNA glycoyslase from Pedobacter heparinus (named Phe SMUG2), which displays catalytic activities towards DNA containing uracil or hypoxanthine/xanthine. Phylogenetic analyses show that SMUG2 enzymes are closely related …

Characterization Of The Recombination Activities Of The Entamoeba Histolytica Rad51 Recombinase, Andrew A. Kelso, Steven D. Goodson, Suchitra Chavan, Amanda F. Say, Audrey Turchick, Deepti Sharma, Leanna L. Ledford, Erin Ratterman, Kristin Leskoske, Ada V. King, Christopher C. Attaway, Yura Bandera, Stephen H. Foulger, Alexander V. Mazin, Lesly A. Temesvari, Michael G. Sehorn

Publications

The protozoan parasite responsible for human amoebiasis is Entamoeba histolytica. An important facet of the life cycle of E. histolytica involves the conversion of the mature trophozoite to a cyst. This transition is thought to involve homologous recombination (HR), which is dependent upon the Rad51 recombinase. Here, a biochemical characterization of highly purified ehRad51 protein is presented. The ehRad51 protein preferentially binds ssDNA, forms a presynaptic filament and possesses ATP hydrolysis activity that is stimulated by the presence of DNA. Evidence is provided that ehRad51 catalyzes robust DNA strand exchange over at least 5.4 kilobase …

Ectopic Expression Of A Cyanobacterial Flavodoxin In Creeping Bentgrass Impacts Plant Development And Confers Broad Abiotic Stress Tolerance, Zhigang Li, Shuangrong Yuan, Haiyan Jia, Fangyuan Gao, Qian Hu, Dongfa Sun, Hong Luo

Publications

Flavodoxin (Fld) plays a pivotal role in photosynthetic microorganisms as an alternative electron carrier flavoprotein under adverse environmental conditions. Cyanobacterial Fld has been demonstrated to be able to substitute ferredoxin (Fd) of higher plants in most electron transfer processes under stressful conditions. We have explored the potential of Fld for use in improving plant stress response in creeping bentgrass (Agrostis stolonifera L.). Overexpression of Fld altered plant growth and development. Most significantly, transgenic (TG) plants exhibited drastically enhanced performance under oxidative, drought and heat stress as well as nitrogen (N) starvation, which was associated with higher water retention and …

Snp-Based High Density Genetic Map And Mapping Of Btwd1 Dwarfing Gene In Barley, Xifeng Ren, Jibin Wang, Lipan Liu, Genlou Sun, Chengdao Li, Hong Luo, Dongfa Sun

Publications

A high-density linkage map is a valuable tool for functional genomics and breeding. A newly developed sequence-based marker technology, restriction site associated DNA (RAD) sequencing, has been proven to be powerful for the rapid discovery and genotyping of genome-wide single nucleotide polymorphism (SNP) markers and for the high-density genetic map construction. The objective of this research was to construct a high-density genetic map of barley using RAD sequencing. 1894 high-quality SNP markers were developed and mapped onto all seven chromosomes together with 68 SSR markers. These 1962 markers constituted a total genetic length of 1375.8 cM and an average of …

Heterologous Expression Of A Rice Mir395 Gene In Nicotiana Tabacum Impairs Sulfate Homeostasis, Ning Yuan, Shuangrong Yuan, Zhigang Li, Dayong Li, Qian Hu, Hong Luo

Publications

Sulfur participates in many important mechanisms and pathways of plant development. The most common source of sulfur in soil –SO₄²⁻– is absorbed into root tissue and distributed into aerial part through vasculature system, where it is reduced into sulfite and finally sulfide within the subcellular organs such as chloroplasts and mitochondria and used for cysteine and methionine biosynthesis. MicroRNAs are involved in many regulation pathways by repressing the expression of their target genes. MiR395 family in Arabidopsis thaliana has been reported to be an important regulator involved in sulfate transport and assimilation, and a high-affinity sulphate transporter …