Life Sciences Commons^™

Wnt And Egf Pathways Act Together To Induce C. Elegans Male Hook Development, Hui Yu, Adeline Seah, Michael A. Herman, Edwin L. Ferguson, H. Robert Horvitz, Paul W. Sternberg

School of Biological Sciences: Faculty Publications

Comparative studies of vulva development between Caenorhabditis elegans and other nematode species have provided some insight into the evolution of patterning networks. However, molecular genetic details are available only in C. elegans and Pristionchus pacificus. To extend our knowledge on the evolution of patterning networks, we studied the C. elegans male hook competence group (HCG), an equivalence group that has similar developmental origins to the vulval precursor cells (VPCs), which generate the vulva in the hermaphrodite. Similar to VPC fate specification, each HCG cell adopts one of three fates (1°, 2°, 3°), and 2° HCG fate specification …

Something Old, Something New, Something Borrowed; How The Thermoacidophilic Archaeon Sulfolobus Solfataricus Responds To Oxidative Stress, Walid S. Maaty, Blake Wiedenheft, Pavel Tarlykov, Nathan Schaff, Joshua Heinemann, Jim Robinson-Cox, Jacob Valenzuela, Amanda Dougherty, Paul H. Blum, C. Martin Lawrence, Trevor Douglas, Mark J. Young, Brian Bothner

School of Biological Sciences: Faculty Publications

To avoid molecular damage of biomolecules due to oxidation, all cells have evolved constitutive and responsive systems to mitigate and repair chemical modifications. Archaea have adapted to some of the most extreme environments known to support life, including highly oxidizing conditions. However, in comparison to bacteria and eukaryotes, relatively little is known about the biology and biochemistry of archaea in response to changing conditions and repair of oxidative damage. In this study transcriptome, proteome, and chemical reactivity analyses of hydrogen peroxide (H2O2) induced oxidative stress in Sulfolobus solfataricus (P2) were conducted. Microarray analysis of mRNA expression showed that 102 transcripts …

Crystallization And Crystal-Packing Studies Of Chlorella Virus Deoxyuridine Triphosphatase, Kohei Homma, Hideaki Moriyama

School of Biological Sciences: Faculty Publications

The 141-amino-acid deoxyuridine triphosphatase (dUTPase) from the algal Chlorella virus IL-3A and its Glu81Ser/Thr84Arg-mutant derivative Mu-22 were crystallized using the hanging-drop vapor-diffusion method at 298 K with polyethylene glycol as the precipitant. An apo IL-3A dUTPase with an aminoterminal T7 epitope tag and a carboxy-terminal histidine tag yielded cubic P213 crystals with unit-cell parameter a = 106.65 A . In the presence of dUDP, the enzyme produced thin stacked orthorhombic P222 crystals with unit-cell parameters a = 81.0, b = 96.2, c = 132.8 A. T7-histidine-tagged Mu-22 dUTPase formed thin stacked rectangular crystals. Amino-terminal histidine-tagged dUTPases did not crystallize but …

Role Of Vapbc Toxin–Antitoxin Loci In The Thermal Stress Response Of Sulfolobus Solfataricus, Charlotte R. Cooper, Amanda J. Daugherty, Sabrina Tachdjian, Paul H. Blum, Robert M. Kelly

School of Biological Sciences: Faculty Publications

TA (toxin–antitoxin) loci are ubiquitous in prokaryotic microorganisms, including archaea, yet

their physiological function is largely unknown. For example, preliminary reports have suggested

that TA loci are microbial stress-response elements, although it was recently shown that knocking

out all known chromosomally located TA loci in Escherichia coli did not have an impact on

survival under certain types of stress. The hyperthermophilic crenarchaeon Sulfolobus solfataricus

encodes at least 26 vapBC (where vap is virulence-associated protein) family TA loci in its

genome. VapCs are PIN (PilT N-terminus) domain proteins with putative ribonuclease activity,

while VapBs are proteolytically labile proteins, which purportedly function …

Caenorhabditis Elegans Genomic Response To Soil Bacteria Predicts Environment-Specific Genetic Effects On Life History Traits, Joseph D. Coolon, Kenneth L. Jones, Timothy C. Todd, Bryanua C. Carr, Michael A. Herman

School of Biological Sciences: Faculty Publications

With the post-genomic era came a dramatic increase in high-throughput technologies, of which transcriptional profiling by microarrays was one of the most popular. One application of this technology is to identify genes that are differentially expressed in response to different environmental conditions. These experiments are constructed under the assumption that the differentially expressed genes are functionally important in the environment where they are induced. However, whether differential expression is predictive of functional importance has yet to be tested. Here we have addressed this expectation by employing Caenorhabditis elegans as a model for the interaction of native soil nematode taxa and …

The Nuclear Receptor Nhr-25 Cooperates With The Wnt/Β-Catenin Asymmetry Pathway To Control Differentiation Of The T Seam Cell In C. Elegans, Martina Hajduskova, Marek Jindra, Michael A. Herman, Masako Asahina

School of Biological Sciences: Faculty Publications

Asymmetric cell divisions produce new cell types during animal development. Studies in Caenorhabditis elegans have identified major signal-transduction pathways that determine the polarity of cell divisions. How these relatively few conserved pathways interact and what modulates them to ensure the diversity of multiple tissue types is an open question. The Wnt/β-catenin asymmetry pathway governs polarity of the epidermal T seam cell in the C. elegans tail. Here, we show that the asymmetry of T-seam-cell division and morphogenesis of the male sensory rays require NHR-25, an evolutionarily conserved nuclear receptor. NHR-25 ensures the neural fate of the T-seam-cell descendants in cooperation …

Ecological Genomics Of Nematode Community Interactions: Model And Non-Model Approaches, Michael A. Herman, Joseph D. Coolon, Kenneth L. Jones, Timothy Todd

School of Biological Sciences: Faculty Publications

The effects of human-induced environmental change are evident at multiple levels of biological organization. To date, most environmental change studies have focused on effects at the ecosystem, community, and organismal levels. However, the ultimate controls of biological responses are located in the genome. Thus, genetic and genomic studies of organismal responses to environmental changes are necessary. Recent advances in genome analysis now make such analyses possible. In this chapter we describe a research approach and program that can begin to span this gap by using genome-enabled approaches to characterize organismal changes and then employing a genetically tractable model organism to …

The Impact Of Co-Occurring Tree And Grassland Species On Carbon Sequestration And Potential Biofuel Production, Ramesh Laungani, Johannes Knops

School of Biological Sciences: Faculty Publications

We evaluated how three co-occurring tree and four grassland species influence potentially harvestable biofuel stocks and above- and belowground carbon pools. After 5 years, the tree Pinus strobus had 6.5 times the amount of aboveground harvestable biomass as another tree Quercus ellipsoidalis and 10 times that of the grassland species. P. strobus accrued the largest total plant carbon pool (1375 gCm -2 or 394 gCm -2 yr), while Schizachyrium scoparium accrued the largest total plant carbon pool among the grassland species (421 gCm -2 or 137 gCm -2 yr). Quercus ellipsoidalis accrued 850 gCm -2, Q. macrocarpa 370 gCm -2, …

Long 3’-Utrs Target Wild-Type Mrnas For Nonsense-Mediated Mrna Decay In Saccharomyces Cerevisiae, Bessie W. Kebaara, Audrey L. Atkin

School of Biological Sciences: Faculty Publications

The nonsense-mediated mRNA decay (NMD) pathway,

present in most eukaryotic cells, is a specialized

pathway that leads to the recognition and rapid

degradation of mRNAs with premature termination

codons and, importantly, some wild-type

mRNAs. Earlier studies demonstrated that aberrant

mRNAs with artificially extended 3’-untranslated

regions (3’-UTRs) are degraded by NMD. However,

the extent to which wild-type mRNAs with long

3’-UTRs are degraded by NMD is not known.

We used a global approach to identify wild-type

mRNAs in Saccharomyces cerevisiae that have

longer than expected 3’-UTRs, and of these

mRNAs tested, 91% were degraded by NMD. We

demonstrate for the first …

Evolution And Pleiotropy Of Trithorax Function In Arabidopsis, Zoya Avramova

School of Biological Sciences: Faculty Publications

The SET domain-containing genes of the TRITHORAX family encode epigenetic factors that maintain the expression of targeted genes. Trithorax homologs have been found in both animals and plants. Since these are thought to have evolved multicellularity independently, common mechanisms of epigenetic regulation must be evolutionarily ancient and derived from a common ancestor. In addition, each lineage has evolved unique mechanisms to expand the original repertoire of epigenetic functions. Phylogenetic analysis of SET domain proteins has outlined some intriguing evolutionary trends. In plants, epigenetic gene silencing mechanisms have been aggressively pursued. In contrast, studies of epigenetic mechanisms maintaining active gene expression …

Interactive Effects Of Time, Co2, N, And Diversity On Total Belowground Carbon Allocation And Ecosystem Carbon Storage In A Grassland Community, E. Carol Adair, Peter B. Reich, Sarah E. Hobbie, Johannes M.H. Knops

School of Biological Sciences: Faculty Publications

Predicting if ecosystems will mitigate or exacerbate rising CO2 requires understanding how elevated CO₂ will interact with coincident changes in diversity and nitrogen (N) availability to affect ecosystem carbon (C) storage. Yet achieving such understanding has been hampered by the difficulty of quantifying belowground C pools and fluxes. Thus, we used mass balance calculations to quantify the effects of diversity, CO₂, and N on both the total amount of C allocated belowground by plants (total belowground C allocation, TBCA) and ecosystem C storage in a periodically burned, 8-year Minnesota grassland biodiversity, CO₂, and N experiment …

Sex Effects On Life Span And Senescence In The Wild When Dates Of Birth And Death Are Unknown, Felix Zajitschek, Chad Brassil, Russell Bonduriansky, Robert C. Brooks

School of Biological Sciences: Faculty Publications

Males and females allocate and schedule reproductive effort in very different ways. Because the timing and amount of reproductive effort influence survival and thus the optimization of life histories, mortality and senescence are predicted to be sex specific. However, age-specific mortality rates of wild animals are often difficult to quantify in natural populations. Studies that report mortality rates from natural populations are, therefore, almost entirely confined to long-lived, easy-to-track species such as large mammals and birds. Here, we employ a novel approach using capture–mark–recapture data from a wild population of black field crickets (Teleogryllus commodus) to test for …

Blood Sampling Reduces Annual Survival In Cliff Swallows (Petrochelidon Pyrrhonota) -- La Toma De Muestras De Sangre Reduce La Supervivencia Anual En Petrochelidon Pyrrhonota, Charles R. Brown, Mary Bomberger Brown

School of Biological Sciences: Faculty Publications

Researchers commonly collect blood samples from wild birds, and most workers assume that blood sampling has no adverse effect on the birds’ survival. Few studies, however, have done controlled comparisons among bled and non-bled individuals and estimated survival using modern statistical methodology. We used a data set on Cliff Swallows (Petrochelidon pyrrhonota) that included 2,945 bled and 7,822 non-bled birds captured at the same times and sites in southwestern Nebraska from 1986 to 2006 to estimate annual survival and recapture probabilities of each group. Blood was collected with brachial venipuncture in amounts varying from 0.3% to 1.2% of …