Life Sciences Commons^™

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 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 …

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 …

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 …

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 …

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 …

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 …

Mitochondrial-Nuclear Epistasis Affects Fitness Within Species But Does Not Contribute To Fixed Incompatibilities Between Species Of Drosophila, Kristi L. Montooth, Colin D. Meiklejohn, Dawn N. Abt, David M. Rand

School of Biological Sciences: Faculty Publications

Efficient mitochondrial function requires physical interactions between the proteins encoded by the mitochondrial and nuclear genomes. Co-evolution between these genomes may result in the accumulation of incompatibilities between divergent lineages. We test whether mitochondrialnuclear incompatibilities have accumulated within the Drosophila melanogaster species subgroup by combining divergent mitochondrial and nuclear lineages and quantifying the effects on relative fitness. Precise placement of nine mtDNAs from D. melanogaster, D. simulans and D. mauritiana into two D. melanogaster nuclear genetic backgrounds reveals significant mitochondrial-nuclear epistasis affecting fitness in females. Combining the mitochondrial genomes with three different D. melanogaster X chromosomes reveals significant epistasis …

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.

Integrating Spatial And Temporal Approaches To Understanding Species Richness, Ethan P. White, S. K. Morgan Ernest, Peter B. Adler, Allen H. Hurlbert, S. Kathleen Lyons

School of Biological Sciences: Faculty Publications

Understanding species richness patterns represents one of the most fundamental problems in ecology. Most research in this area has focused on spatial gradients of species richness, with a smaller area of emphasis dedicated to understanding the temporal dynamics of richness. However, few attempts have been made to understand the linkages between the spatial and temporal patterns related to richness. Here, we argue that spatial and temporal richness patterns and the processes that drive them are inherently linked, and that our understanding of richness will be substantially improved by considering them simultaneously. The species–time–area relationship provides a case in point: successful …

Analysis Of Mirna Modifications, Bin Yu, Xuemei Chen

School of Biological Sciences: Faculty Publications

After transcription, a large number of cellular RNAs employ modifications to increase their diversity and functional potential. Modifications can occur on the base, ribose, or both, and are important steps in the maturation of many RNAs. Our lab recently showed that plant microRNAs (miRNAs) possess a 2′-O-methyl group on the ribose of the 3′ terminal nucleotide, and that this methyl group is added after miRNA/miRNA* formation. One function of this modification is to protect miRNAs from 3′ terminal uridylation by an unknown enzymatic activity. It is possible that uridylation of miRNAs triggers their degradation. Here we describe a …