Digital Commons Network^™

Apple 1-Aminocyclopropane-1-Carboxylate Synthase In Complex With The Inhibitor L-Aminoethoxyvinylglycine: Evidence For A Ketimine Intermediate, Guido Capitani, Darla L. Mccarthy, Heinz Gut, Markus G. Grütter

University Faculty Publications and Creative Works

The 1.6-Å crystal structure of the covalent ketimine complex of apple 1-aminocyclopropane-1-carboxylate (ACC) synthase with the potent inhibitor L-aminoethoxyvinylglycine (AVG) is described. ACC synthase catalyzes the committed step in the biosynthesis of ethylene, a plant hormone that is responsible for the initiation of fruit ripening and for regulating many other developmental processes. AVG is widely used in plant physiology studies to inhibit the activity of ACC synthase. The structural assignment is supported by the fact that the complex absorbs maximally at 341 nm. These results are not in accord with the recently reported crystal structure of the tomato ACC synthase …

Estimating The Latitudinal Origins Of Migratory Birds Using Hydrogen And Sulfur Stable Isotopes In Feathers: Influence Of Marine Prey Base, Casey A. Lott, Timothy D. Meehan, Julie A. Heath

Julie Heath

Hydrogen stable isotope analysis of feathers is an important tool for estimating the natal or breeding latitudes of nearctic-neotropical migratory birds. This method is based on the latitudinal variation of hydrogen stable isotope ratios in precipitation in North America (iDp) and the inheritance of this variation in newly formed feathers (iDf). We hypothesized that the typically strong relationship between iDp and iDf would be decoupled in birds that forage in marine food webs because marine waters have relatively high iD values compared to iD values for local precipitation. Birds that forage on marine prey bases should also have feathers with …

Evidence For An Epigenetic Mechanism By Which Hsp90 Acts As A Capacitor For Morphological Evolution, Vincent E. Sollars, Xiangyi Lu, Li Xiao, Xiaoyan Wang, Mark D. Garfinkel, Douglas M. Ruden

Biochemistry and Microbiology

Morphological alterations have been shown to occur in Drosophila melanogaster when function of Hsp90 (heat shock 0-kDa protein 1α, encoded by Hsp83) is compromised during development1. Genetic selection maintains the altered phenotypes in subsequent generations1. Recent experiments have shown, however, that phenotypic variation still occurs in nearly isogenic recombinant inbred strains of Arabidopsis thaliana2. Using a sensitized isogenic D. melanogaster strain, iso-KrIf-1, we confirm this finding and present evidence supporting an epigenetic mechanism for Hsp90’s capacitor function, whereby reduced activity of Hsp90 induces a heritably altered chromatin state. The altered chromatin state is evidenced by ectopic expression …

The Effects Of Prescribed Fire On Millipede And Salamander Populations In A Southern Appalachian Deciduous Forest., Alison Baird Gagan

Electronic Theses and Dissertations

Prescribed fire has increased as a forest management practice in southern Appalachia, but investigations into the effects of this silvicultural treatment on non-game wildlife inhabiting the region is limited. This study investigated the effects of prescribed fire on millipede and salamander populations. Seventeen sites within the Cherokee National Forest in east Tennessee that were treated once with prescribed fire between 1998 and 2002 were examined in the spring of 2002. Each burned plot was paired with an adjacent unburned plot.

The number of individual millipedes and salamanders collected from burned plots was compared to the corresponding control plot. Millipedes declined …

Characteristic Genome Rearrangements In Experimental Evolution Of Saccharomyces Cerevisiae, Maitreya J. Dunham, Hassan Badrane, Tracy Ferea, Julian Adams, Patrick O. Brown, Frank Rosenzweig, David Botstein

Biological Sciences Faculty Publications

Genome rearrangements, especially amplifications and deletions, have regularly been observed as responses to sustained application of the same strong selective pressure in microbial populations growing in continuous culture. We studied eight strains of budding yeast (Saccharomyces cerevisiae) isolated after 100-500 generations of growth in glucose-limited chemostats. Changes in DNA copy number were assessed at single-gene resolution by using DNA microarray-based comparative genomic hybridization. Six of these evolved strains were aneuploid as the result of gross chromosomal rearrangements. Most of the aneuploid regions were the result of translocations, including three instances of a shared breakpoint on chromosome 14 immediately adjacent to …

Assessment Of Fungal Diversity Using Terminal Restriction Fragment (Trf) Pattern Analysis: Comparison Of 18s And Its Ribosomal Regions, N. S. Lord, Christopher W. Kaplan, P. Shank, Christopher L. Kitts, Susan L. Elrod

Biological Sciences

Assessment of fungal diversity in environmental samples is currently a challenge. Several recently developed molecular methods offer new avenues for determining the presence and diversity of fungi in complex microbial communities. Terminal restriction fragment (TRF) pattern analysis was tested as a method for assessing the fungal molecular diversity of a terrestrial microbial community. Community DNA was isolated from sand samples taken from a pilot-scale petroleum-contaminated land treatment unit. PCR amplification was carried out using primers, one of which was fluorescently labeled, designed to hybridize to conserved sequences in the fungal ribosomal small subunit (18S) or the internal transcribed spacer ITS1–5.8S–ITS2 …

Coastal Habitat Use By Wood Storks During The Non-Breeding Season, A. L. Bryan Jr., Karen F. Gaines, C. S. Eldridge

Karen F. Gaines

We documented roosting and foraging habitat use by Wood Storks during the post-breeding season in the coastal zone of Georgia from 1994-1998. Larger, more persistent aggregations of roosting storks typically oc- curred in enclosed wetlands on large estuarine islands. Smaller, more ephemeral aggregations tended to occur on salt marsh/upland ecotones, where storks appeared to be waiting for local conditions (tide levels) to become suit- able for foraging. Examination of habitat types within a 2-km radius of the larger (mean > 10 storks/survey) vs. smaller (mean <10 storks/survey) roosts showed that surrounding habitat structure, including those used for for- aging, were similar. Foraging storks typically fed in close proximity (median = 0.5 km) to large roosts, much closer than storks using coastal wetlands during the breeding season. Tidal creeks were used almost exclusively as foraging habitat (92%). Storks and other wading birds were almost always present when the study bird arrived. The foraging patterns of study birds and four storks carrying radios suggested that storks often used the same foraging sites and/ or marsh systems in the non-breeding season. Coastal Wood Storks apparently selected roosting sites based on the presence of conspecifics, abundant local prey, or possibly as shelter from adverse weather conditions

Behavior Of Escherichia Coli O157:H7 In Tomato And Processed Tomato Products, Broderick Eribo, Mogessie Ashenafi

Department of Biology Faculty Publications

The survival of E. coli O157:H7 in acid foods for weeks and its prolonged survival in refrigerated acid foods are well documented. This prompted the study to evaluate survival of E. coli O157:H7 in tomato and processed tomato products. The pH of the various products ranged from 4.2 to 4.8 and some products contained preservatives such as vinegar. Samples were separately inoculated with a mixture of four E. coli O157:H7 strains previously isolated from hamburger meat at lower and higher initial inoculum levels, incubated at 4 and 25 °C and assayed for survival at regular intervals. In fresh whole tomato, …

Shar-Pei Mediates Cell Proliferation Arrest During Imaginal Disc Growth In Drosophila, Madhuri Kango-Singh, Riitta Nolo, Chunyao Tao, Patrik Verstreken, P. Robin Hiesinger, Hugo J. Bellen, Georg Halder

Biology Faculty Publications

During animal development, organ size is determined primarily by the amount of cell proliferation, which must be tightly regulated to ensure the generation of properly proportioned organs. However, little is known about the molecular pathways that direct cells to stop proliferating when an organ has attained its proper size. We have identified mutations in a novel gene, shar-pei, that is required for proper termination of cell proliferation during Drosophila imaginal disc development. Clones of shar-pei mutant cells in imaginal discs produce enlarged tissues containing more cells of normal size. We show that this phenotype is the result of both …

Convergent Demographic Effects Of Insect Attack On Related Thistles In Coastal Vs. Continental Dunes, John L. Maron, Julie K. Combs, Svata M. Louda

Biological Sciences Faculty Publications

Insect herbivory is common, but the conditions under which it reduces the fitness and population size of plants remain poorly understood. We quantified population-level impacts of floral herbivory by specialized insects on cobweb thistle (Cirsium occidentale var. occidentale) in a California coastal dune ecosystem, and then compared these demographic effects to those published for Platte thistle (Cirsium canescens) in similarly designed exclusion experiments in the continental sand dune ecosystem in the Great Plains. As a separate test of the strength of the seed-to-seedling linkage, we quantified seedling establishment rates in seed addition plots and compared these …

An Examination Of Predatory Pressures On Piping Plovers Nesting At Breezy Point, New York, Brook Lauro, John Tanacredi Ph.D.

Faculty Works: CERCOM

This study examines predatory threats to Piping Plovers (Charadrius melodus) nesting at Breezy Point, Gateway National Recreation Area, New York. Several methods used include: 1) an evaluation of reproductive success data with documentation of predation to eggs and chicks, 2) predator surveys, and 3) an artificial nest study. The range of breeding pairs nesting from 1988-1996 was 11-19, with an average of 15.8 (SE ± 0.79) pairs/season. The average number of eggs hatched and chicks fledged per year for pairs was 2.2 ± 0.23 and 0.8 ± 0.16 respectively. Reasons for egg losses often went undetected (68%) but …

Rhoa Kinase And Protein Kinase C Participate In Regulation Of Rabbit Stomach Fundus Smooth Muscle Contraction, Paul H. Ratz, Joel T. Meehl, Thomas Eddinger

Biological Sciences Faculty Research and Publications

1. The degree to which the RhoA kinase (ROK) blockers, Y-27632 (1 µM) and HA-1077 (10 µM), and the PKC blocker, GF-109203X (1 µM), reduced force produced by carbachol, a muscarinic receptor agonist, and phenylephrine, an α-adrenoceptor agonist, was examined in rabbit stomach fundus smooth muscle.

2. When examining the effect on cumulative carbachol concentration-response curves (CRCs), ROK and PKC blockers shifted the potency (~EC50) to the right but did not reduce the maximum response.

3. In a single-dose carbachol protocol using moderate (~EC50) and maximum carbachol concentrations, Y-27632 and HA-1077 reduced peak force, but GF-109203X had no effect. By …

Rotational Lift: Something Different Or More Of The Same?, Jeffrey A. Walker Phd

Faculty Publications

This paper addresses the question, do the rotational forces in the hovering fruit fly Drosophila melanogaster reflect something different (the Magnus effect) or more of the same (circulatory-and-attached-vortex force)? The results of an unsteady blade-element model using empirically derived force coefficients from translating (root-oscillating) wings are compared with recent results derived from both the measured forces on a dynamically scaled Drosophila wing and the computational fluid dynamic (CFD)-modeled forces on a virtual Drosophila wing. The behavior of the forces in all three models during wing rotation supports the hypothesis that rotational lift is not a novel aerodynamic mechanism but is …

Nonadditive Genetic Effects In Animal Behavior, Lisa M. Meffert, Sara K. Hicks, Jennifer L. Regan

Faculty Publications

Heritabilities, commonly used to predict evolutionary potential, are notoriously low for behaviors. Apart from strong contributions of environmental variance in reducing heritabilities, the additive genetic components can be very low, especially when they are camouflaged by nonadditive genetic effects. We first report the heritabilities of courtship traits in founder‐flush and control populations of the housefly (Musca domestica L.). We estimated the heritability of each male and female display through the regression of the courtships involving daughters and sons (with randomly selected mates) onto the “midparental” courtship values of their parents. Overall, the average heritability was significantly higher for the …

Plasticity And Genetic Diversity May Allow Saltcedar To Invade Cold Climates In North America, Jason P. Sexton, J. K. Mckay, Anna Sala

Biological Sciences Faculty Publications

Two major mechanisms have been proposed to explain the ability of introduced populations to colonize over large habitat gradients, despite significant population bottlenecks during introduction: (1) Broad environmental tolerance-successful invaders possess life history traits that confer superior colonizing ability and/or phenotypic plasticity, allowing acclimation to a wide range of habitats. (2) Local adaptation-successful invaders rapidly adapt to local selective pressures. However, even with bottlenecks, many introduced species exhibit surprisingly high levels of genetic variation and thus the potential for evolutionary increases in invasive traits and plasticity. Here we assess the invasive potential of Tamarix ramosissima, by examining the degree of …

Coastal Habitat Use By Wood Storks During The Non-Breeding Season, A. L. Bryan Jr., Karen F. Gaines, C. S. Eldridge

Faculty Research & Creative Activity

We documented roosting and foraging habitat use by Wood Storks during the post-breeding season in the coastal zone of Georgia from 1994-1998. Larger, more persistent aggregations of roosting storks typically oc- curred in enclosed wetlands on large estuarine islands. Smaller, more ephemeral aggregations tended to occur on salt marsh/upland ecotones, where storks appeared to be waiting for local conditions (tide levels) to become suit- able for foraging. Examination of habitat types within a 2-km radius of the larger (mean > 10 storks/survey) vs. smaller (mean <10 storks/survey) roosts showed that surrounding habitat structure, including those used for for- aging, were similar. Foraging storks typically fed in close proximity (median = 0.5 km) to large roosts, much closer than storks using coastal wetlands during the breeding season. Tidal creeks were used almost exclusively as foraging habitat (92%). Storks and other wading birds were almost always present when the study bird arrived. The foraging patterns of study birds and four storks carrying radios suggested that storks often used the same foraging sites and/ or marsh systems in the non-breeding season. Coastal Wood Storks apparently selected roosting sites based on the presence of conspecifics, abundant local prey, or possibly as shelter from adverse weather conditions

Bergmann's Rule In Ectotherms: A Test Using Freshwater Fishes, Mark C. Belk, Derek D. Houston

Faculty Publications

Understanding patterns of variation in body size within and among species is a central question in evolutionary ecology (Schlichting and Pigliucci 1998). The most well known pattern of variation in body size is Bergmann's rule (Bergmann 1847; Mayr 1956). The intraspecific version of Bergmann's rule holds that within endothermic species, body size increases with increasing latitude (or decreasing temperature; Blackburn et al. 1999; Ashton et al. 2000). In general, mammals conform to this rule (Ashton et al. 2000).

Whole-Genome Analysis Of Dorsal-Ventral Patterning In The Drosophila Embryo, Angelike Stathopoulos, Madeleine Van Drenth, Albert Erives, Michele Markstein, Michael Levine

Michele Markstein

The maternal Dorsal regulatory gradient initiates the differentiation of several tissues in the early Drosophila embryo. Whole-genome microarray assays identified as many as 40 new Dorsal target genes, which encode a broad spectrum of cell signaling proteins and transcription factors. Evidence is presented that a tissue-specific form of the NF-Y transcription complex is essential for the activation of gene expression in the mesoderm. Tissue-specific enhancers were identified for new Dorsal target genes, and bioinformatics methods identified conserved cis-regulatory elements for coordinately regulated genes that respond to similar thresholds of the Dorsal gradient. The new Dorsal target genes and enhancers represent …

Development Of Form And Function In Peripheral Auditory Structures Of The Zebrafish (Danio Rerio), Dennis M. Higgs, Audrey K. Rollo, Marcy J. Souza, Arthur N. Popper

Biological Sciences Publications

Investigations of the development of auditory form and function have, with a few exceptions, thus far been largely restricted to birds and mammals, making it difficult to postulate evolutionary hypotheses. Teleost fishes represent useful models for developmental investigations of the auditory system due to their often extensive period of posthatching development and the diversity of auditory specializations in this group. Using the auditory brainstem response and morphological techniques we investigated the development of auditory form and function in zebrafish ~Danio rerio) ranging in size from 10 to 45 mm total length. We found no difference in auditory sensitivity, response latency, …

Gag Proteins Of The Two Drosophila Telomeric Retrotransposons Are Targeted To Chromosome Ends, Svetlana Rashkova, Sarah E. Karam, Rebecca Kellum, Mary-Lou Pardue

Biology Faculty Publications

Drosophila telomeres are formed by two non-LTR retrotransposons, HeT-A and TART, which transpose only to chromosome ends. Successive transpositions of these telomeric elements yield arrays that are functionally equivalent to the arrays generated by telomerase in other organisms. In contrast, other Drosophila non-LTR retrotransposons transpose widely through gene-rich regions, but not to ends. The two telomeric elements encode very similar Gag proteins, suggesting that Gag may be involved in their unique targeting to chromosome ends. To test the intrinsic potential of these Gag proteins for targeting, we tagged the coding sequences with sequence of GFP and expressed the constructs …

Protein Folding Studies Of Adipocyte Lipid Binding Protein And Homologous Mesophilic And Thermophilic Type I Dna Polymerases, Allyn J. Schoeffler

Honors Theses

No abstract provided.

Individual, Temporal, And Seasonal Variation In Sperm Concentration In Tree Swallows, Michael P. Lombardo, Armetris N. Forman, Matthew R. Czarnowski, Patrick A. Thorpe

Peer Reviewed Publications

We determined sperm concentrations in Tree Swallows (Tachycineta bicolor) by manually expressing semen samples from males during prelaying, egg-laying, incubation, and nestling periods. Sperm concentrations varied by orders of magnitude (0-10⁹ sperm mL^-1) among males. Sperm concentrations were highest during the incubation period and lowest during the prelaying period. None of the samples collected during the prelaying, egg-laying, and incubation periods were devoid of sperm. In contrast, 45% of samples collected during the nestling period lacked sperm. Sperm concentrations (1) did not vary over the course of the morning during prelaying, egg-laying, and incubation periods …

Groel Expression In Gyrb Mutants Of Borrelia Burgdorferi, Janet Alverson, D. Scott Samuels

Biological Sciences Faculty Publications

GroEL protein and groEL mRNA transcript were up-regulated in gyrB mutants of Borrelia burgdorferi, a causative agent of Lyme disease. Furthermore, the protein and transcript levels in gyrB mutants were greater than those in experimentally heat-shocked cultures of wild-type B. burgdorferi. Circular DNA in the gyrB mutants was more relaxed than in wild-type cells, although groEL is on the linear chromosome of B. burgdorferi. To our knowledge, this is the first evidence, albeit indirect, for the effect of DNA topology on gene expression from a linear DNA molecule in a bacterium.

Brief Communications: Rapid And Costly Ageing In Wild Male Flies, Russell Bonduriansky, Chad Brassil

School of Biological Sciences: Faculty Publications

Ageing (senescence) has never been demonstrated convincingly in any insect in the wild, where mean life-spans are probably much shorter than in the laboratory¹, and most evidence for senescence in other wild animals (such as mammals) is limited to their reduced survival with age². Here we show that ageing is detectable in wild populations of a very short-lived insect, the antler fly (Protopiophila litigata), and causes debilitating and costly effects that force a decline not only in survival probability, but also in the reproductive rate of males. Our findings argue against the possibility of …

Syd-1, A Presynaptic Protein With Pdz, C2 And Rhogap-Like Domains, Specifies Axon Identity In C. Elegans, Steven Hallam, Alexandr Goncharov, Jason Mcewen, Renee Baran, Yishi Jin

Renee Baran

Axons are defined by the presence of presynaptic specializations at specific locations. We show here that loss-of-function mutations in the C. elegans gene syd-1 cause presynaptic specializations to form in the dendritic processes of GABA-expressing motor neurons during initial differentiation. At a later developmental stage, however, syd-1 is not required for the polarity respecification of a subset of these neurons. The SYD-1 protein contains PDZ, C2 and rho–GTPase activating protein (GAP)-like domains, and is localized to presynaptic terminals in mature neurons. A truncated SYD-1 that lacks the rhoGAP domain interferes with neurite outgrowth and guidance. Our data indicate that syd-1 …

Workshop On Sustainable Development Of Marine Fish Farming In Wa, Peter Rogers, R Fletcher

Fisheries management papers

The purpose of this paper is twofold. First to provide an overview of the role of government and more particularly the Department of Fisheries and second to outline government expectations for aquaculture development agencies in the implementation of sustainable development initiatives and the effect this could have on the management of aquaculture within WA.

Contributions To The Mammalogy Of Mongolia, With A Checklist Of The Species Of The Country, David S. Tinnin, Jon L. Dunnum, Jorge A. Salazar-Bravo, Nyamsuren Batsaikhan, M. Scott Burt, Scott Lyell Gardner, Terry L. Yates

Harold W. Manter Laboratory of Parasitology: Faculty and Staff Publications

We present accounts for 40 species of mammals collected from 15 localities in the Mongolian People's Republic. Accounts include taxonomic, morphometric, reproductive and ecological information, as well as trap effort and success. In addition, we include a brief history of mammalogical work within Mongolia, a taxonomically updated species list for the country, and a list of institutions with holdings of Mongolian mammals.

Mad2 And Bubr1 Function In A Single Checkpoint Pathway That Responds To A Loss Of Tension, Katie Shannon, Julie C. Canman, Edward D. Salmon

Biological Sciences Faculty Research & Creative Works

The spindle checkpoint monitors microtubule attachment and tension at kinetochores to ensure proper chromosome segregation. Previously, PtK1 cells in hypothermic conditions (23°C) were shown to have a pronounced mitotic delay, despite having normal numbers of kinetochore microtubules. At 23°C, we found that PtK1 cells remained in metaphase for an average of 101 min, compared with 21 min for cells at 37°C. The metaphase delay at 23°C was abrogated by injection of Mad2 inhibitors, showing that Mad2 and the spindle checkpoint were responsible for the prolonged metaphase. Live cell imaging showed that kinetochore Mad2 became undetectable soon after chromosome congression. Measurements …

Anaphase Onset Does Not Require The Microtubule-Dependent Depletion Of Kinetochore And Centromere-Binding Proteins, Julie C. Canman, Nitin Sharma, Aaron F. Straight, Katie Shannon, Guowei Fang, Edward D. Salmon

Biological Sciences Faculty Research & Creative Works

Spindle checkpoint proteins, such as Mad2 and BubR1, and the motors dynein/dynactin and CENP-E usually leave kinetochores prior to anaphase onset by microtubule-dependent mechanisms. Likewise, 'chromosome passenger proteins' including INCENP are depleted from the centromeres after anaphase onset and then move to the midzone complex, an event that is essential for cytokinesis. Here we test whether the cell cycle changes that occur at anaphase onset require or contribute to the depletion of kinetochore and centromere proteins independent of microtubules. This required the development of a novel non-antibody method to induce precocious anaphase onset in vivo by using a bacterially expressed …

Relationships Between Blueberry Flower Age, Pollination, And Conidial Infection By Monilinia Vaccinii-Corymbosi, Jeffery S. Lehman, Henry K. Ngugi, Harald Scherm

Biology and Earth Science Faculty Scholarship

Monilinia vaccinii-corymbosi infects open blueberry flowers via the gynoecial pathway, leading to mummification of the developing fruit. To determine the effect of flower age on infection, stigmata were inoculated with conidia of M. vaccinii-corymbosi between 0 and 5 days after anthesis, fungal growth rates through the stylar canal were measured in detached flowers in the laboratory, and fruit disease incidence was determined in plants grown in the greenhouse. Hyphal growth rates were greatest in flowers inoculated on the day of anthesis, declined linearly with increasing flower age at inoculation (r = 0.921; P < 0.0001; n = 12), and were unaffected by the presence or absence of pollen applied at the time of inoculation. In greenhouse-grown plants, the percentage of infected fruit decreased exponentially with increasing flower age at inoculation (R = 0.878; P = 0.0057; n = 10), with disease incidence ranging from 76.4% for flowers inoculated on the day of anthesis to 15.5% for those inoculated 4 days later. Fruit disease incidence in the greenhouse was linearly correlated with hyphal growth rates in detached flowers (r = 0.985; P < 0.0001; n = 9), justifying the use of detached flowers when investigating gynoecial infection by M. vaccinii-corymbosi. In separate experiments, the effects of timing and sequence of pollination and inoculation on hyphal growth rates through the stylar canal and on disease incidence were investigated. Application of pollen to detached flowers 1 or 2 days before inoculation reduced hyphal growth rates by between 14.0 and 42.9% compared with flowers that received pollen and conidia simultaneously. Similarly, reductions in fruit disease incidence by between 9.5 and 18.3% were observed on greenhouse-grown plants for pollination-to-inoculation intervals ranging from 1 to 4 days. These results document that newly opened flowers are most susceptible to infection by M. vaccinii-corymbosi and that fruit disease incidence is reduced if pollination occurs at least 1 day before inoculation. Strategies that lead to early pollination of newly opened flowers may be useful for managing mummy berry disease in the field.