Life Sciences Commons^™

Evidence For Microbial Fe(Iii) Reduction In Anoxic, Mining-Impacted Lake Sediments (Lake Coeur D’Alene, Idaho), David E. Cummings, Anthony W. March, Benjamin Bostick, Stefan Spring, Frank Caccavo Jr., Scott Fendorf, Frank Rosenzweig

Biological Sciences Faculty Publications

Mining-impacted sediments of Lake Coeur d'Alene, Idaho, contain more than 10% metals on a dry weight basis, approximately 80% of which is iron. Since iron (hydr)oxides adsorb toxic, ore-associated elements, such as arsenic, iron (hydr)oxide reduction may in part control the mobility and bioavailability of these elements. Geochemical and microbiological data were collected to examine the ecological role of dissimilatory Fe(III)-reducing bacteria in this habitat. The concentration of mild-acid-extractable Fe(II) increased with sediment depth up to 50 g kg⁻¹, suggesting that iron reduction has occurred recently. The maximum concentrations of dissolved Fe(II) in interstitial water (41 mg liter …

Response Of The Tick Dermacentor Variabilis (Acari: Ixodidae) To Hemocoelic Inoculation Of Borrelia Burgdorferi (Spirochetales), Robert Johns, Daniel E. Sonenshine, Wayne L. Hynes

Biological Sciences Faculty Publications

When Borrelia burgdorferi B31 low passage strain spirochetes were directly injected into the hemocoel of Dermacentor variabilis(Say) females, the bacteria were cleared from the hemocoel within < 24 h. Viable spirochetes were not found in hemolymph, salivary gland, or ovary tissues by subculturing or by IFA. The hemocyte population increased ≈6 times within the first 6 h after inoculation compared with the uninoculated controls. In contrast, the soluble total hemolymph protein content decreased inversely with the increase in hemocytes. Borreliacidal activity was demonstrated with cell-free hemolymph from D. variabilis. In vitro antimicrobial assays using hemolymph from borrelia-challenged and nonchallenged ticks resulted in 72% spirochete reductions compared with only 11.5%, respectively, within 1 h. Additional evidence of induced antimicrobial hemolymph protein activity was demonstrated by SDS-PAGE, which revealed upregulation of a lysozyme-like peptide (≈ 15 kDa) (22% increase) and the induction of a ≈ 5.8 kDa peptide in the B. burgdorferi-challenged ticks. In contrast with the nonvector borne Bacillus subtilis …

Absence Of Insect Juvenile Hormones In The American Dog Tick, Dermacentor Veriabilis (Say) (Acari: Ixodidae), And In Ornithodoros Parkeri Cooley (Acari: Argasidae), P. A. Neese, Daniel E. Sonenshine, V. L. Kallapur, C. S. Apperson, R. M. Roe

Biological Sciences Faculty Publications

Synganglia, salivary gland, midgut, ovary, fat body and muscle alone and in combination from the ixodid tick, Dermacentor variabilis (Say), or the argasid tick, Ornithodoros parkeri Cooley, were incubated in vitro in separate experiments with _L-[methyl-³H]methionine and farnesoic acid or with [1-¹⁴C]acetate. Life stages examined in D. variabilis were 3 and 72 h old (after ecdysis) unfed nymphs, partially fed nymphs (18 and 72 h after attachment to the host), fully engorged nymphs (2 d after detachment from host), 3 and 72 h old (after eclosion) unfed females, partially fed unmated females (12–168 …

Estuarine Relationships Between Zooplankton Community Structure And Trophic Gradients, Gyung Soo Park, Harold G. Marshall

Biological Sciences Faculty Publications

Zooplankton and water quality parameters were investigated at eight mesohaline stations in the lower Chesapeake Bay and Elizabeth River from January through December 1994 to identify the changes of zooplankton community structure with increased eutrophication. The total micro- and mesozooplankton biomass decreased with the increase of eutrophication. However, the relative proportion of microzooplankton increased with increased eutrophication. Within highly eutrophied waters, the small oligotrichs (m) and rotifers dominated the total zooplankton biomass (as carbon). However, tintinnids, copepod nauplii and mesozooplankton significantly decreased with the increase of eutrophication. These patterns were consistent throughout the seasons and had significant relationships statistically. These …

Hyaluronidases Of Gram-Positive Bacteria, Wayne L. Hynes, Sheryl Lynne Walton

Biological Sciences Faculty Publications

Bacterial hyaluronidases, enzymes capable of breaking down hyaluronate, are produced by a number of pathogenic Gram-positive bacteria that initiate infections at the skin or mucosal surfaces. Since reports of the hyaluronidases first appeared, there have been numerous suggestions as to the role of the enzyme in the disease process. Unlike some of the other more well studied virulence factors, much of the information on the role of hyaluronidase is speculative, with little or no data to substantiate proposed roles. Over the last 5 years, a number of these enzymes from Gram-positive organisms have been cloned, and the nucleotide sequence determined. …

Molecular Evidence For A New Bacteriophage Of Borrelia Burgdorferi, Christian H. Eggers, D. Scott Samuels

Biological Sciences Faculty Publications

We have recovered a DNase-protected, chloroform-resistant molecule of DNA from the cell-free supernatant of a Borrelia burgdorferi culture. The DNA is a 32-kb double-stranded linear molecule that is derived from the 32-kb circular plasmids (cp32s) of the B. burgdorferi genome. Electron microscopy of samples from which the 32-kb DNA molecule was purified revealed bacteriophage particles. The bacteriophage has a polyhedral head with a diameter of 55 nm and appears to have a simple 100-nm-long tail. The phage is produced constitutively at low levels from growing cultures of some B. burgdorferi strains and is inducible to higher levels with 10 mu …

Three-Dimensional Structure Of A Complex Between The Death Domains Of Pelle And Tube, Tsan Xiao, Par Towb, Steven A. Wasserman, Stephen R. Sprang

Biological Sciences Faculty Publications

The interaction of the serine/threonine kinase Pelle and adaptor protein Tube through their N-terminal death domains leads to the nuclear translocation of the transcription factor Dorsal and activation of zygotic patterning genes during Drosophila embryogenesis. Crystal structure of the Pelle and Tube death domain heterodimer reveals that the two death domains adopt a six-helix bundle fold and are arranged in an open-ended linear array with plastic interfaces mediating their interactions. The Tube death domain has an insertion between helices 2 and 3, and a C-terminal tail making significant and indispensable contacts in the heterodimer. In vivo assays of Pelle and …

Systematic Changes In Gene Expression Patterns Following Adaptive Evolution In Yeast, Tracy L. Ferea, David Botstein, Patrick O. Brown, R. Frank Rosenzweig

Biological Sciences Faculty Publications

Culturing a population of Saccharomyces cerevisiae for many generations under conditions to which it is not optimally adapted selects for fitter genetic variants. This simple experimental design provides a tractable model of adaptive evolution under natural selection. Beginning with a clonal, founding population, independently evolved strains were obtained from three independent cultures after continuous aerobic growth in glucose-limited chemostats for more than 250 generations. DNA microarrays were used to compare genome-wide patterns of gene expression in the evolved strains and the parental strain. Several hundred genes were found to have significantly altered expression in the evolved strains. Many of these …

Development Of A System For Genetic Manipulation Of Bartonella Bacilliformis, James M. Battisti, Michael F. Minnick

Biological Sciences Faculty Publications

Lack of a system for site specific genetic manipulation has severely hindered studies on the molecular biology of all Bartonella species. We report the first site-specific mutagenesis and complementation for a Bartonella species. A highly transformable strain of B. bacilliformis, termed JB584, was isolated and found to exhibit a significant increase in transformation efficiency with the broad-host-range plasmid pBBR1MCS-2, relative to wild-type strains. Restriction analyses of genomic preparations with the methylation-sensitive restriction enzymes ClaI and StuI suggest that strain JB584 possesses a dcm methylase mutation that contributes to its enhanced transformability. A suicide plasmid, pUB1, which contains a polylinker, a …

Using Atlas Data To Model The Distribution Of Woodpecker Species In The Jura, France, Claudine Tobalske, Bret W. Tobalske

Biological Sciences Faculty Publications

Breeding bird atlases providing distribution data at a regional scale are becoming increasingly common. To assess the ability of such data to develop bread-scale bird-habitat models, we used data from a breeding bird atlas and landscape variables obtained From a geographic information system (GIS) to study the distribution of seven woodpecker species in the Jura, France: the Black (Dryocopus martins), Green (Picus viridis). Grey-headed (P. canus), Great Spotted (Dendrocopos major), Middle Spotted (D. medius), and Lesser Spotted (D. minor) Woodpeckers, and the Wryneck (Jynx torquilla). We used logistic regression to develop predictive models from variables that described each 575-ha atlas …

Two-Metal-Ion Catalysis In Adenylyl Cyclase, John J.G. Tesmer, Roger K. Sunahara, Roger A. Johnson, Gilles Gosselin, Alfred G. Gilman, Stephen R. Sprang

Biological Sciences Faculty Publications

Adenylyl cyclase (AC) converts adenosine triphosphate (ATP) to cyclic adenosine monophosphate, a ubiquitous second messenger that regulates many cellular functions. Recent structural studies have revealed much about the structure and function of mammalian AC but have not fully defined its active site or catalytic mechanism. Four crystal structures were determined of the catalytic domains of AC in complex with two different ATP analogs and various divalent metal ions. These structures provide a model for the enzyme- substrate complex and conclusively demonstrate that two metal ions bind in the active site. The similarity of the active site of AC to those …

Positions In The 30s Ribosomal Subunit Proximal To The 790 Loop As Determined By Phenanthroline Cleavage, Gregory W. Muth, Scott P. Hennelly, Walter E. Hill

Biological Sciences Faculty Publications

Positioning rRNA within the ribosome remains a challenging problem. Such positioning is critical to understanding ribosome function, as various rRNA regions interact to form suitable binding sites for ligands, such as tRNA and mRNA. We have used phenanthroline, a chemical nuclease, as a proximity probe, to help elucidate the regions of rRNA that are near neighbors of the stem-loop structure centering at nt 790 in the 16S rRNA of the Escherichia coli 30S ribosomal subunit. Using phenanthroline covalently attached to a DNA oligomer complementary to nt 787-795, we found that nt 582-584, 693-694, 787-790, and 795-797 were cleaved robustly and …

Effects Of Fire On The Demography Of The Endangered, Geophytic Herb Silene Spaldingii (Caryophyllaceae), Peter Lesica

Biological Sciences Faculty Publications

Understanding the effects of disturbances such as fire on plant demography helps elucidate the mechanisms that cause changes in community composition. I studied the effects of spring and fall fires on Silene spaldingii, an endangered perennial herb of grasslands in northwest Montana. Individual S. spaldingii plants were mapped, and size and flowering were recorded for 1 yr prior and 5 yr subsequent to the burn treatments. Enhanced seedling recruitment (70–410%) and a 22% increase in population size were the principal effects of fire on S. spaldingii, and fall burn plots had lower recruitment than spring burn plots. These effects were …

Structure Of G(Iα1)·Gppnhp, Autoinhibition In A Gα Protein-Substrate Complex, David E. Coleman, Stephen R. Sprang

Biological Sciences Faculty Publications

The structure of the G protein G(i 1/4 ) complexed with the nonhydrolyzable GTP analog guanosine-5'-(βγ-imino)triphosphate (GppNHp) has been determined at a resolution of 1.5 Å. In the active site of G(i 1/4 )·GppNHp, a water molecule is hydrogen bonded to the side chain of Glu⁴³ and to an oxygen atom of the γ-phosphate group. The side chain of the essential catalytic residue Gln²⁰⁴ assumes a conformation which is distinctly different from that observed in complexes with either guanosine 5'-O-3-thiotriphosphate or the transition state analog GDP·A1F₄^-. Hydrogen bonding and steric interactions position Gln²⁰⁴ such …

Mycorrhizae Indirectly Enhance Competitive Effects Of An Invasive Forb On A Native Bunchgrass, Marilyn J. Marler, Catherine A. Zabinski, Ragan M. Callaway

Biological Sciences Faculty Publications

Mycorrhizae are important mediators of plant competition, but little is known about the role of mycorrhizae in the intense competitive effects that exotic plants can have on native species. In the greenhouse, we tested the effect of arbuscular mycorrhizal (AM) fungi on interspecific competition between Centaurea maculosa and Festuca idahoensis, on intraspecific competition between individuals of both species, and the growth of C. maculosa with either inorganic or organic phosphorus. Mycorrhizae had no direct effect on either species, but mycorrhizae increased C. maculosa's negative effect on F. idahoensis. When competing with C. maculosa, nonmycorrhizal F. idahoensis were 171% larger than …

Biological-Control Herbivores May Increase Competitive Ability Of The Noxious Weed Centaurea Maculosa, Ragan M. Callaway, Thomas H. Deluca, Wendy M. Belliveau

Biological Sciences Faculty Publications

Biocontrol organisms are generally applied in an attempt to reduce the vigor of target species and provide native species with an competitive advantage. We tested the effectiveness of a widely used biocontrol moth, Agapeta zoegana (knapweed root moth) for two years in the field and found that it had no significant direct effect on the biomass of Centaurea maculosa (spotted knapweed), one of the most destructive invasive plants in North America. Instead of releasing a native grass from competition, the reproductive output of Festuca idahoensis planted with Centaurea was significantly lower when neighboring Centaurea had been attacked by Agapeta. In …

Adaptive Strategies That Reduce Predation On Caribbean Spiny Lobster Postlarvae During Onshore Transport, Charles A. Acosta, Mark J. Butler Iv

Biological Sciences Faculty Publications

Like many marine species with meroplanktonic larvae, the Caribbean spiny lobster (Panulirus argus) has a postlarval stage that moves from the oceanic plankton to inshore nurseries only under specific environmental conditions (i.e., at night, in the surface water layer, on the flood tide, and during new moon), presumably to avoid predation or to enhance onshore transport. Using held and mesocosm experiments, we compared predation on planktonic postlarvae swimming at night near the surface and bottom over coastal habitats along typical offshore-inshore transport paths and determined whether predation rates differed between lunar periods (new moon vs, full moon) and with prey …

Cleavage Of A 23s Rrna Pseudoknot By Phenanthroline-Cu(Ii), G. W. Muth, Charles M. Thompson, Walter E. Hill

Biological Sciences Faculty Publications

Studying the intricate folding of rRNA within the ribosome remains a complex problem. Phenanthroline-Cu(II) complexes cleave phosphodiester bonds in rRNA in specific regions, apparently especially where the rRNA structure is constrained in some fashion. We have introduced phenanthroline-copper complexes into 50S Escherichia coli ribosomal subunits and shown specific cleavages in the regions containing nucleotides 60-66 and 87-100. This specificity of cleavage is reduced when the ribosome is heated to 80 degrees C and reduced to background when the ribosomal proteins are extracted and the cleavage repeated on protein-free 23S rRNA, It has been suggested that nucleotides 60-66 and 87-95 in …

Toward An Evolutionary Understanding Of Song Diversity In Oscines, Erick Greene

Biological Sciences Faculty Publications

No abstract provided.

Nmr Solution Structure Of Plastocyanin From The Photosynthetic Prokaryote, Prochlorothrix Hollandica, Charles R. Babu, Brian F. Volkman, George S. Bullerjahn

Biological Sciences Faculty Publications

The solution structure of a divergent plastocyanin (PC) from the photosynthetic prokaryote Prochlorothrix hollandica was determined by homonuclear H-1 NMR spectroscopy. Nineteen structures were calculated from 1222 distance restraints, yielding a family of structures having an average rmsd of 0.42 +/- 0.08 Angstrom, for backbone atoms and 0.71 +/- 0.07 Angstrom for heavy atoms to the mean structure. No distance constraint was violated by more than 0.26 Angstrom in the structure family. Despite the low number of conserved residues shared with other PC homologues, the overall folding pattern of P. hollandica PC is similar to other PCs, in that the …

Bush Lupine Mortality, Altered Resource Availability, And Alternative Vegetaion States, John L. Maron, Robert L. Jefferies

Biological Sciences Faculty Publications

Nitrogen-fixing plants, by altering the availability of soil N, potentially facilitate plant invasion. Here we describe how herbivore-driven mortality of a native N-fixing shrub, bush lupine (Lupinus arboreus), increases soil N and light availability, which promotes invasion by introduced grasses to the detriment of a native plant community.

Soils under live and dead lupine stands contained large amounts of total N, averaging 3.14 mg N/g dry mass of soil (398 g/m²) and 3.45 mg N/g dry mass of soil (438 g/m²), respectively, over four years. In contrast, similar lupine-free soil was low in N …

Exploring Cost Constraints On Stem Elongation In Plants Using Phenotypic Manipulation, Don Cipollini, Jack C. Schultz

Biological Sciences Faculty Publications

Negative associations between individual life‐history traits of an organism are referred to as life‐history trade‐offs (Stearns 1992; Zera et al. 1998). The existence of costly trade‐offs is thought to have favored the evolution of phenotypic plasticity as a mechanism through which organisms can account for environmental heterogeneity while modulating costs and benefits incurred by fixed allocation to competing functions (Bradshaw 1965; Stearns 1992; Sultan 1995; Dudley and Schmitt 1996; Pigliucci 1996). In plants, the ability to modify stem elongation in response to environmental cues appears to be a classic form of adaptive phenotypic plasticity (Sultan 1995; Gedroc et al. 1996). …

Phylogenetic Relationships In Nuphar (Nymphaeaceae): Evidence From Morphology, Chloroplast Dna, And Nuclear Ribosomal Dna, Donald Padgett, D. H. Les, G. E. Crow

Biological Sciences Faculty Publications

The genus Nuphar consists of yellow-flowered waterlilies and is widely distributed in north-temperate bodies of water. Despite regular taxonomic evaluation of these plants, no explicit phylogenetic hypotheses have been proposed for the genus. We investigated phylogenetic relationships in Nuphar using morphology and sequences of the chloroplast gene matK and of the internal transcribed spacer (ITS) regions of nuclear ribosomal DNA. Two major lineages within Nuphar are consistently resolved with the morphological and molecular data sets. One lineage comprises New World taxa and the other represents a primarily Old World lineage. Relationships within the major lineages were poorly resolved by morphology …

Expression Of Cell Adhesion In Molecules In Murine Placentas And A Placental Cell Line, Jeffery Bowen, J. S. Hunt

Biological Sciences Faculty Publications

Integrins and vascular cell adhesion molecule-1 (VCAM-1) are required for normal placental development. In this study, integrin subunits α4, αv, β1, and β3, and VCAM-1 were investigated for expression in uteroplacental units (gestation day [g.d.] 6 and 8) and placentas (g.d. 10, 12, 14, 16, and 18) of Swiss-Webster mice. All subunits and VCAM-1 mRNA (identified by reverse transcriptase polymerase chain reaction [RT-PCR]) and protein (detected by immunofluorescence) were present in all tissues throughout gestation. VCAM-1 was expressed strongly in the ectoplacental cone and trophoblast giant cells, α4 was expressed strongly by trophoblast giant cells and moderately by spongiotrophoblast and …

Nomenclatural Novelties In Nuphar (Nymphaeaceae), Donald Padgett

Biological Sciences Faculty Publications

Recent revisionary and cladistic studies in Nuphar Sm. resulted in the following nomenclatural amendments: two novel sections are described (sect. Nuphar and sect. Astylus), five new combinations are proposed (N. advena subsp. orbiculata, N. advena subsp. ozarkana, N. advena subsp. ulvacea, N. pumila subsp. sinensis, N. pumila subsp. oguraensis), and one species, N. oguraensis Miki, is lectotypified.

Habitat Relationships Of Landbirds In The Northern Region, Usda Forest Service, Richard L. Hutto, Jock S. Young

Biological Sciences Faculty Publications

A series of first-generation habitat-relationships models for 83 bird species were detected in a 3-year study on point counts conducted in association with the USDA Forest Service's Northern Region Landbird Monitoring Program. The models depict probabilities of detection for each of the bird species on 100-m-radius, 10-minute point counts conducted across a series of major vegetation cover types. Based on these models, some bird species appear to be restricted in their habitat distribution to: (1) postfire, standing-dead forests, (2) relatively uncut, older forests, (3) harvested forest types, (4) marshes, (5) riparian environments, and (6) grasslands and sagebrush. Such restricted distributions …

The Cause And Consequence Of Ontogenetic Changes In Social Aggregation In New Zealand Spiny Lobsters, Mark J. Butler Iv, Alistair B. Macdiarmid, John D. Booth

Biological Sciences Faculty Publications

Ontogenetic changes in the behavior, spatial distribution, or habitat use of a species are presumably adaptations to ecological forces that differ in their effect on various life stages. The New Zealand rock lobster Jasus edwardsii is one of several species of spiny lobster that exhibits dramatic ontogenetic shifts in sociality and spatial distribution, and we tested whether such changes are adaptive. We first surveyed several natural populations of J. edwardsii to document size-specific differences in aggregation. To determine if chemical cues discharged by conspecifics promote aggregation of certain ontogenetic stages, we tested the responsiveness of lobsters of 3 ontogenetic stages …

Nucleotide Sequence Of The Streptococcin A-Ff22 Lantibiotic Regulon: Model For Production Of The Lantibiotic Sa-Ff22 By Strains Of Streptococcus Pyogenes, Robert E. Mclaughlin, Joseph J. Ferretti, Wayne L. Hynes

Biological Sciences Faculty Publications

Streptococcin A-FF22 (SA-FF22) is a type AII linear lantibiotic produced by Streptococcus pyogenes strain FF22. Sequence analysis of an approximate 10 kb region of DNA showed it to contain nine open reading frames arranged in three operons responsible for regulation, biosynthesis and immunity of SA-FF22. This region is organized similarly to the Lactococcus lactis lacticin 481 region, however, unlike lacticin 481, a two-component regulatory system is essential for SA-FF22 production. located immediately downstream of the scn region is a putative transposase gene, the presence of which supports earlier data that indicated a mobile nature to this region. (©) 1999 Published …

Role Of Iron, Light, And Silicate In Controlling Algal Biomass In Subantarctic Waters Se Of New Zealand, Robert Michael Mckay, Philip Boyd, Julie Laroche, Mark Gall, Russell Frew

Biological Sciences Faculty Publications

Phytoplankton processes in subantarctic (SA) waters southeast of New Zealand were studied during austral autumn and spring 1997. Chlorophyll a (0.2–0.3 μg L⁻¹) and primary production (350–650 mg C m⁻² d⁻¹) were dominated by cells μm (cyanobacteria) in both seasons. The photochemical efficiency of photosystem II (F_υ/F_m) of cells was low (0.3), indicating physiological stress. Dissolved Fe (DFe) levels in surface waters were subnanomolar, and the molecular marker flavodoxin indicated that cells were iron stressed. In contrast, Subtropical Convergence (STC) and subtropical waters had higher algal biomass/production levels, particularly …

Growth And Feeding Studies On The Algal Feeding Stage Of A Pfiesteria-Like Dinoflagellate, David W. Seaborn, A. Michelle Seaborn, William M. Dunstan, Harold G. Marshall

Biological Sciences Faculty Publications

The dinoflagellate Cryptoperidiniopsis sp. was isolated from sediment samples taken from Virginia estuaries, and established in culture for subsequent growth and feeding studies. The maximum abundance, or yield, of Cryptoperidiniopsis is exponentially related to the concentration of algal prey and is saturated at about 4.00 X 10⁵ mL^-1. Salinity from 10-20 ppt and temperature between 15-25 C have no effect on the yield of this form of Cryptoperidiniopsis. Light intensity has a secondary effect in that the algal prey reproduces more quickly in higher light as they are being grazed. Growth rates of Cryptoperidiniopsis were …