Digital Commons Network^™

Differences In Hiv Burden And Immune Activation Within The Gut Of Hiv-Positive Patients Receiving Suppressive Antiretroviral Therapy, Steven A. Yukl, Sara Gianella, Elizabeth Sinclair, Lorrie Epling, Qingsheng Li, Lijie Duan, Alex L.M. Choi, Valerie Girling, Terence Ho, Peilin Li, Katsuya Fujimoto, Harry Lampiris, C. Bradley Hare, Mark Pandori, Ashley T. Haase, Huldrych F. Günthard, Marek Fischer, Amandeep K. Shergill, Kenneth Mcquaid, Diane V. Havlir, Joseph K. Wong

School of Biological Sciences: Faculty Publications

Background. The gut is a major reservoir for human immunodeficiency virus (HIV) in patients receiving antiretroviral therapy (ART). We hypothesized that distinct immune environments within the gut may support varying levels of HIV.

Methods. In 8 HIV-1-positive adults who were receiving ART and had CD4⁺ T cell counts of >200 cells/μL and plasma viral loads of <40 copies/mL, levels of HIV and T cell activation were measured in blood samples and endoscopic biopsy specimens from the duodenum, ileum, ascending colon, and rectum.

Results. HIV DNA and RNA levels per CD4⁺ T cell were higher in all 4 gut sites compared with those in the blood. HIV DNA levels increased from the duodenum to the rectum, whereas the median HIV …

A Detailed Phylogenetic Analysis Of Fiv In The United States, Eric A. Weaver

School of Biological Sciences: Faculty Publications

Background: Feline immunodeficiency virus (FIV) is a lentivirus associated with AIDS-like illnesses in cats and has been used as a model for the study of human immunodeficiency virus (HIV). A feature of HIV and FIV infection is the continually increasing divergence among viral isolates between different individuals, as well as within the same individuals.

Methodology/Principal Findings: The goal of this study was to determine the phylogenetic patterns of viral isolates obtained within the United States (U.S.) by focusing on the variable, V3-V4, region of the FIV envelope gene.

Conclusions/Significance: Data indicate that FIV, from within the U.S., localize to four …

The Capsid Protein Of Turnip Crinkle Virus Overcomes Two Separate Defense Barriers To Facilitate Systemic Movement Of The Virus In Arabidopsis, Mingxia Cao, Xiaohong Yi, Kristen Willie, Junyan Lin, Xiuchun Zhang, Margaret G. Redinbaugh, Anne E. Simon, Thomas Jack Morris, Feng Qu

School of Biological Sciences: Faculty Publications

The capsid protein (CP) of Turnip crinkle virus (TCV) is a multifunctional protein needed for virus assembly, suppression of RNA silencing-based antiviral defense, and long-distance movement in infected plants. In this report, we have examined genetic requirements for the different functions of TCV CP and evaluated the interdependence of these functions. A series of TCV mutants containing alterations in the CP coding region were generated. These alterations range from single-amino-acid substitutions and domain truncations to knockouts of CP translation. The latter category also contained two constructs in which the CP coding region was replaced by either the cDNA of a …

The Spatial Influence Of Aboveground Diversity On Belowground Communities, T. Bliss, Tom Powers, Chad Brassil

School of Biological Sciences: Faculty Publications

Little is known about the effect of diversity surrounding a focal plant species on the belowground community under that species. At least two alternative hypotheses exist. First, studies involving a range of ecosystems and taxonomic groups have shown that changes in diversity in one group of species can promote diversity in other groups. Alternatively, many studies in soil ecology have shown that belowground communities are strongly determined by the dominant aboveground species. To better understand the role of aboveground diversity on belowground communities, we examined soil nematode communities directly under Panicum virgatum (switchgrass) in areas of high and low surrounding …

Glycopeptidome Of A Heavily N-Glycosylated Cell Surface Glycoprotein Of Dictyostelium Implicated In Cell Adhesion, Christa L. Feasley, Jennifer M. Johnson, Christopher M. West, Catherine P. Chia

School of Biological Sciences: Faculty Publications

Genetic analysis has implicated the cell surface glycoprotein gp130 in cell interactions of the social amoeba Dictyostelium, and information about the utilization of the 18 N-glycosylation sequons present in gp130 is needed to identify critical molecular determinants of its activity. Various glycomics strategies, including mass spectrometry of native and derivatized glycans, monosaccharide analysis, exoglycosidase digestion, and antibody binding, were applied to characterize a nonanchored version secreted from Dictyostelium. s-gp130 is modified by a predominant Man8GlcNAc4 species containing bisecting and intersecting GlcNAc residues and additional high-mannose N-glycans substituted with sulfate, methyl-phosphate, and/or core R3-fucose. Site mapping confirmed the occupancy …

Dual Functions Of Interferon Regulatory Factors 7c In Epstein-Barr Virus–Mediated Transformation Of Human B Lymphocytes, Yong Zhao, Dongsheng Xu, Yanjun Jiang, Luwen Zhang

School of Biological Sciences: Faculty Publications

Epstein-Barr virus (EBV) infection is associated with several human malignancies. Interferon (IFN) regulatory factor 7 (IRF-7) has several splicing variants, and at least the major splicing variant (IRF-7A) has oncogenic potential and is associated with EBV transformation processes. IRF-7C is an alternative splicing variant with only the DNA-binding domain of IRF-7. Whether IRF-7C is present under physiological conditions and its functions in viral transformation are unknown. In this report, we prove the existence of IRF-7C protein and RNA in certain cells under physiological conditions, and find that high levels of IRF-7C are associated with EBV transformation of human primary B …

Completed Genome Sequence Of The Anaerobic Iron-Oxidizing Bacterium Acidovorax Ebreus Strain Tpsy, Kathryne G. Byrne-Bailey, Karrie A. Weber, Antinea H. Chair, Saumyaditya Bose, Traci Knox, Trisha L. Spanbauer, Olga Chertkov, John D. Coates

School of Biological Sciences: Faculty Publications

Acidovorax ebreus strain TPSY is the first anaerobic nitrate-dependent Fe(II) oxidizer for which there is a completed genome sequence. Preliminary protein annotation revealed an organism optimized for survival in a complex environmental system. Here, we briefly report the completed and annotated genome sequence of strain TPSY.

Positive Carotenoid Balance Correlates With Greater Reproductive Performance In A Wild Bird, Rebecca Safran, Kevin J. Mcgraw, Matt Wilkins, Joanna K. Hubbard, Julie Marling

School of Biological Sciences: Faculty Publications

Background: Carotenoids can confer somatic and reproductive benefits, but most evidence is from captive animal experimentation or single time-point sampling. Another perhaps more informative means by which to assess physiological contributions to animal performance is by tracking an individual’s ability to increase or sustain carotenoids or other health-related molecules over time, as these are likely to be temporally variable.

Methodology/Principal Findings: In a field study of North American barn swallows (Hirundo rustica erythrogaster), we analyzed within-individual changes in carotenoid concentrations by repeatedly sampling the carotenoid profiles of individuals over the course of the breeding season. Our results demonstrate …

Genome Sequence Of The Pea Aphid Acyrthosiphon Pisum, Jennifer A. Brisson, Stephen Richards, International Aphid Genomics Consortium

School of Biological Sciences: Faculty Publications

Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological …

The Role Of Litter Quality Feedbacks In Terrestrial Nitrogen And Phosphorus Cycling, Johannes M.H. Knops, David A. Wedin, Shahid Naeem

School of Biological Sciences: Faculty Publications

Many studies in ecosystem ecology argue for strong control of litter quality over nitrogen (N) cycling. We developed a model for temperate grasslands to test the importance of litter quality in decomposition for N and phosphorus (P) cycling based on the following premises. First, terrestrial N and P cycling differ fundamentally because N is a structural component of the soil organic matter (SOM), whereas P is not. Secondly, SOM has a much lower C:N ratio than litter inputs. Thirdly, litter decomposition follows an exponential decay with 20% of the original litter mass turning into SOM. Fourth, litter N concentration shows …

Viral Trans-Factor Independent Replication Of Human Papillomavirus Genomes, Daraporn Pittayakhajonwut, Peter C. Angeletti

School of Biological Sciences: Faculty Publications

Background: Papillomaviruses (PVs) establish a persistent infection in the proliferating basal cells of the epithelium. The viral genome is replicated and maintained as a low-copy nuclear plasmid in basal keratinocytes. Bovine and human papillomaviruses (BPV and HPV) are known to utilize two viral proteins; E1, a DNA helicase, and E2, a transcription factor, which have been considered essential for viral DNA replication. However, growing evidence suggests that E1 and E2 are not entirely essential for stable replication of HPV. Results: Here we report that multiple HPV16 mutants, lacking either or both E1 and E2 open reading frame (ORFs) and the …

Ignoring Population Structure Can Lead To Erroneous Predictions Of Future Population Size, Brigitte Tenhumberg

School of Biological Sciences: Faculty Publications

Predictions of future population size often assume population structures are stable. Are we missing the boat if we ignore the occurrence of unstable or transient dynamics?

Agricultural crops are regularly infested with insect pests whose population size can reach outbreak densities in some years, causing considerable income loss to farmers. In general, the risk of pest outbreaks is highest when insects disperse to crop fields early in the growing season and the population growth rate is high. The population growth rate measures how much the population size (i.e., number of individuals of a species in a defined area) changes per …

Purification And Characterization Of Cytoplasmic Nadp+- Isocitrate Dehydrogenase, And Amplification Of The Nadp+-Idh Gene From The Wing-Dimorphic Sand Field Cricket, Gryllus Firmus, Anthony J. Zera, Susan Newman, David Berkheim, Christine Black, Lindsay Klug, Erica Crone

School of Biological Sciences: Faculty Publications

Cytoplasmic NADP+-isocitrate dehydrogenase (NADP+-IDH) has been purified and characterized, and its gene sequenced in many animal, plant, and yeast species. However, much less information is available on this enzyme-gene in insects. As a first step in investigating the biochemical and molecular mechanisms by which NADP+-IDH contributes to adaptations for flight vs. reproduction in insects, the enzyme was purified to homogeneity in the wing-dimorphic cricket, Gryllus firmus, characterized, and its corresponding gene sequenced. Using a combination of polyethylene glycol precipitation, Cibacron-Blue affinity chromatography, and hydrophobic interaction chromatography the enzyme was purified 291-fold (7% yield; specific activity = 15.8 μmol NADPH/min/mg …

The Polypeptide Syn67 Interacts Physically With Human Holocarboxylase Synthetase, But Is Not A Target For Biotinylation, Yousef I. Hassan, Hideaki Moriyama, Janos Zempleni

School of Biological Sciences: Faculty Publications

Holocarboxylase synthetase (HCS) catalyzes the binding of biotin to lysines in carboxylases and histones in two steps. First, HCS catalyzes the synthesis of biotinyl-5′-AMP; second, the biotinyl moiety is ligated to lysine residues. It has been proposed that step two is fairly promiscuous, and that protein biotinylation may occur in the absence of HCS as long as sufficient exogenous biotinyl-5′- AMP is provided. Here, we identified a novel polypeptide (Syn67) with a basic patch of lysines and arginines. Yeast-two-hybrid assays and limited proteolysis assays revealed that both N- and C-termini of HCS interact with Syn67. A potential target lysine in …

Nm23-H1 Can Induce Cell Cycle Arrest And Apoptosis In B Cells, Tathagata Choudhuri, Masanao Murakami, Rajeev Kaul, Sushil K. Sahu, Suchitra Mohanty, Subhash C. Verma, Pankaj Kumar, Erle S. Robertson

School of Biological Sciences: Faculty Publications

Nm23-H1 is a well-known tumor metastasis suppressor, which functions as a nucleoside-diphosphate kinase converting nucleoside diphosphates to nucleoside triphosphates with an expense of ATP. It regulates a variety of cellular activities, including proliferation, development, migration and differentiation known to be modulated by a series of complex signaling pathway. Few studies have addressed the mechanistic action of Nm23-H1 in the context of these cellular processes. To determine the downstream pathways modulated by Nm23-H1, we expressed Nm23-H1 in a Burkitt lymphoma derived B-cell line BJAB and performed pathway specific microarray analysis. The genes with significant changes in expression patterns were clustered in …

Association Of Rs780094 In Gckr With Metabolic Traits And Incident Diabetes And Cardiovascular Disease: The Aric Study, Mark Bi, Wen Hong Linda Kao, Eric Boerwinkle, Ron C. Hoogeveen, Laura J. Rasmussen-Torvik, Brad C. Astor, Kari E. North, Joseph Coresh, Anna Kottgen

School of Biological Sciences: Faculty Publications

Objective: The minor T-allele of rs780094 in the glucokinase regulator gene (GCKR) associates with a number of metabolic traits including higher triglyceride levels and improved glycemic regulation in study populations of mostly European ancestry. Using data from the Atherosclerosis Risk in Communities (ARIC) Study, we sought to replicate these findings, examine them in a large population-based sample of African American study participants, and to investigate independent associations with other metabolic traits in order to determine if variation in GKCR contributes to their observed clustering. In addition, we examined the association of rs780094 with incident diabetes, coronary heart disease (CHD), and …

Interspecific Relationships Among Growth, Mortality And Xylem Traits Of Woody Species From New Zealand, Sabrina E. Russo, Kerry L. Jenkins, Susan K. Wiser, Maria Uriarte, Richard P. Duncan, David A. Coomes

School of Biological Sciences: Faculty Publications

1. Wood density is considered a key functional trait influencing the growth and survival of woody plants and has been shown to be related to a slow-fast rate-of-living continuum. Wood density is, however, an emergent trait arising from several vascular properties of wood, including the diameter and frequency of xylem conduits.

2. We aimed to test the hypotheses that there is a set of inter-related trade-offs linked to the different functions of wood, that these trade-offs have direct consequences for tree growth and survival and that these trade-offs underlie the observed correlations between wood density and demographic rates. We evaluated …

Locomotion In Response To Shifting Climate Zones: Not So Fast, Martin E. Feder, Theodore Garland Jr., James H. Marden, Anthony J. Zera

School of Biological Sciences: Faculty Publications

Although a species’ locomotor capacity is suggestive of its ability to escape global climate change, such a suggestion is not necessarily straightforward. Species vary substantially in locomotor capacity, both ontogenetically and within/among populations, and much of this variation has a genetic basis. Accordingly, locomotor capacity can and does evolve rapidly, as selection experiments demonstrate. Importantly, even though this evolution of locomotor capacity may be rapid enough to escape changing climate, genetic correlations among traits (often due to pleiotropy) are such that successful or rapid dispersers are often limited in colonization or reproductive ability, which may be viewed as a trade-off. …

Genetic Conflict And Sex Chromosome Evolution, Colin D. Meiklejohn, Yun Tao

School of Biological Sciences: Faculty Publications

Chromosomal sex determination systems create the opportunity for the evolution of selfish genetic elements that increase the transmission of one sex chromosome at the expense of its homolog. Because such selfish elements on sex chromosomes can reduce fertility and distort the sex ratio of progeny, unlinked suppressors are expected to evolve, bringing different regions of the genome into conflict over the meiotic transmission of the sex chromosomes. Here we argue that recurrent genetic conflict over sex chromosome transmission is an important evolutionary force that has shaped a wide range of seemingly disparate phenomena including the epigenetic regulation of genes expressed …

The Abl And Arg Non-Receptor Tyrosine Kinases Regulate Different Zones Of Stress Fiber, Focal Adhesion, And Contractile Network Localization In Spreading Fibroblasts, Justin G. Peacock, Brian A. Couch, Anthony J. Koleske

School of Biological Sciences: Faculty Publications

Directed cell migration requires precise spatial control of F-actin-based leading edge protrusion, focal adhesion (FA) dynamics, and actomyosin contractility. In spreading fibroblasts, the Abl family kinases, Abl and Arg, primarily localize to the nucleus and cell periphery, respectively. Here we provide evidence that Abl and Arg exert different spatial regulation on cellular contractile and adhesive structures. Loss of Abl function reduces FA, F-actin, and phosphorylated myosin light chain (pMLC) staining at the cell periphery, shifting the distribution of these elements more to the center of the cell than in wild-type (WT) and arg^—/— cells. Conversely, loss of Arg function …

Synaptic Clustering Of Psd-95 Is Regulated By C-Abl Through Tyrosine Phosphorylation, Karen Perez De Arce, Lorena Varela-Nallar, Olivia Farias, Alejandra Cifuentes, Paulina Bull, Brian A. Couch, Anthony J. Koleske, Nibaldo C. Inestrosa, Alejandra R. Alvarez

School of Biological Sciences: Faculty Publications

The c-Abl tyrosine kinase is present in mouse brain synapses, but its precise synaptic function is unknown. We found that c-Abl levels in the rat hippocampus increase postnatally, with expression peaking at the first postnatal week. In 14 d in vitro hippocampal neuron cultures, c-Abl localizes primarily to the postsynaptic compartment, in which it colocalizes with the postsynaptic scaffold protein postsynaptic density protein-95 (PSD-95) in apposition to presynaptic markers. c-Abl associates with PSD-95, and chemical or genetic inhibition of c-Abl kinase activity reduces PSD-95 tyrosine phosphorylation, leading to reduced PSD-95 clustering and reduced synapses in treated neurons. c-Abl can phosphorylate …

The Effects Of Flower Color Transitions On Diversification Rates In Morning Glories (Ipomoea Subg. Quamoclit, Convolvulaceae), Stacey Dewitt Smith, Richard E. Miller, Sarah P. Otto, Richard G. Fitzjohn, Mark D. Rausher

School of Biological Sciences: Faculty Publications

As in many clades of flowering plants, the Quamoclit clade of morning glories (Ipomoea subgenus Quamoclit) exhibits unequal proportions of different flower colors, with pigmented species outnumbering unpigmented species by nearly a factor of 7. We examined three possible macroevolutionary explanations for this pattern: (1) asymmetric transition rates between pigmented and unpigmented flowers; (2) low transition rates preventing the flower colors from reaching equilibrium; and (3) differential diversification. In order to discriminate among these explanations, we employ the newly-developed Binary-State Speciation and Extinction (BiSSE) model, which jointly estimates transition rates among states and the speciation and extinction rates …

Activity And Toxicity Of Farnesol Towards Candida Albicans Are Dependent On Growth Conditions, Melanie L. Langford, Sahar Hasim, Kenneth W. Nickerson, Audrey L. Atkin

School of Biological Sciences: Faculty Publications

Farnesol interacts with Candida albicans as both a quorum-sensing molecule and toxic agent, but confusion abounds regarding which conditions promote these distinct responses. Farnesol sensitivity was measured when inoculum cell history and size, temperature, and growth media were altered. Parameters for farnesol tolerance/ sensitivity were defined, validating previous studies and identifying new variables, such as energy availability. This study clearly defines what farnesol concentrations are lethal to C. albicans, based on environmental conditions.

Molecular Determinants Of Hiv-1 Subtype C Coreceptor Transition From R5 To R5x4, Hong Zhang, Damien C. Tully, Tiejun Zhang, Hideaki Moriyama, Jesse Thompson, Charles Wood

School of Biological Sciences: Faculty Publications

The molecular mechanism(s) underlying transition from CCR5 to CXCR4 usage of subtype C viruses remain largely unknown. We previously identified a subtype C HIV-1 infected child whose virus demonstrated CXCR4 usage along with CCR5 upon longitudinal follow-up. Here we delineated the molecular determinants of Env involved in expanded coreceptor usage. Residue changes in three positions of Env V3 domain are critical for the dual-tropic phenotype. These include: substitution of arginine at position 11, MG or LG insertion between positions 13 and 14, and substitution of threonine at the position immediately downstream of the GPGQ crown. Introducing these mutations into V3 …

Increased Dendrite Branching In Aβpp/Ps1 Mice And Elongation Of Dendrite Arbors By Fasudil Administration, Brian A. Couch, George J. Demarco, Shannon L. Gourley, Anthony J. Koleske

School of Biological Sciences: Faculty Publications

Amyloid-β (Aβ) overproduction and dendrite arbor atrophy are hallmarks of Alzheimer’s disease. The RhoA GTPase (Rho) signals through Rho kinase (ROCK) to control cytoskeletal dynamics and regulate neuron structure. Hyperactive Rho signaling destabilizes neurons leading to dendritic regression that can be rescued by genetic or pharmacological reduction of ROCK signaling. To understand what effect reduced ROCK signaling has on the dendrite arbors of mice that overproduce Aβ, we administered the ROCK inhibitor fasudil to AβPP/PS1 transgenic mice. We report that increased dendrite branching occurs in AβPP/PS1 mice and that fasudil promotes …

Compositions And Methods For Controlling Plant Parasitic Nematodes, Harold N. Trick, Judith L. Roe, Timothy C. Todd, Michael A. Herman

School of Biological Sciences: Faculty Publications

The present invention relates to compositions and methods for controlling nematode infestation of plants. In particular, the present invention provides vectors comprising sequences designed to control nematodes by RNA interference (RNAi) and transgenic plants transformed with Such vectors.

Evolution Of The Kdo2-Lipid A Biosynthesis In Bacteria, Stephen O. Opiyo, Rosevelt L. Pardy, Hideaki Moriyama, Etsuko N. Moriyama

School of Biological Sciences: Faculty Publications

Background: Lipid A is the highly immunoreactive endotoxic center of lipopolysaccharide (LPS). It anchors the LPS into the outer membrane of most Gram-negative bacteria. Lipid A can be recognized by animal cells, triggers defense-related responses, and causes Gram-negative sepsis. The biosynthesis of Kdo₂-lipid A, the LPS substructure, involves with nine enzymatic steps.

Results: In order to elucidate the evolutionary pathway of Kdo₂-lipid A biosynthesis, we examined the distribution of genes encoding the nine enzymes across bacteria. We found that not all Gram-negative bacteria have all nine enzymes. Some Gram-negative bacteria have no genes encoding …

Seed Availability And Insect Herbivory Limit Recruitment And Adult Density Of Native Tall Thistle, F. Leland Russell, Karen E. Rose, Svata M. Louda

School of Biological Sciences: Faculty Publications

Understanding spatial and temporal variation in factors influencing plant regeneration is critical to predicting plant population growth. We experimentally evaluated seed limitation, insect herbivory, and their interaction in the regeneration and density of tall thistle (Cirsium altissimum) across a topographic ecosystem productivity gradient in tallgrass prairie over two years. On ridges and in valleys, we used a factorial experiment manipulating seed availability and insect herbivory to quantify effects of: seed input on seedling density, insect herbivory on juvenile density, and cumulative impacts of both seed input and herbivory on reproductive adult density. Seed addition increased seedling densities at …

Phosphatidylinositol 5-Phosphate Links Dehydration Stress To The Activity Of Arabidopsis Trithorax-Like Factor Atx1, Ivan Ndamukong, David R. Jones, Hanna Lapko, Nullin Divecha, Zoya V. Avramova

School of Biological Sciences: Faculty Publications

Background: Changes in gene expression enable organisms to respond to environmental stress. Levels of cellular lipid second messengers, such as the phosphoinositide PtdIns5P, change in response to a variety of stresses and can modulate the localization, conformation and activity of a number of intracellular proteins. The plant trithorax factor (ATX1) trimethylates the lysine 4 residue of histone H3 (H3K4me3) at gene coding sequences, which positively correlates with gene transcription. Microarray analysis has identified a target gene (WRKY70) that is regulated by both ATX1 and by the exogenous addition of PtdIns5P in Arabidopsis. Interestingly, ATX1 …

Variation In Leaf Stomatal Traits Of 28 Tree Species In Relation To Gas Exchange Along An Edaphic Gradient In A Bornean Rain Forest, Sabrina E. Russo, Whitney Logan Cannon, Christian Elowsky, Sylvester Tan, Stuart J. Davies

School of Biological Sciences: Faculty Publications

Premise of the study: Quantifying variation in functional traits associated with shifts in the species composition of plant communities along resource gradients helps identify environmental attributes important for community assembly. Stomates regulate the balance between carbon assimilation and water status in plants. If environmental attributes affecting photosynthetic water-use efficiency govern species distribution along an edaphic gradient, then adaptive variation in stomatal traits of plant species specializing on different soils should reflect belowground resource availability.

Methods: We tested this hypothesis by quantifying stomatal trait variation in understory saplings of 28 Bornean tree species in relation to gas exchange and …