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2001

Biological Sciences Faculty Publications

Articles 1 - 28 of 28

Full-Text Articles in Life Sciences

Facilitation And Competition On Gradients In Alpine Plant Communities, Philippe Choler, Richard Michalet, Ragan M. Callaway Dec 2001

Facilitation And Competition On Gradients In Alpine Plant Communities, Philippe Choler, Richard Michalet, Ragan M. Callaway

Biological Sciences Faculty Publications

We conducted a neighbor removal experiment in natural alpine plant communities of the southwestern Alps to test for the relative importance of competitive and facilitative interactions along elevational and topographical gradients. The experimental sites were chosen to encompass most of the floristic diversity observed along gradients of elevation and topography, which are the two main ecological gradients associated with alpine plant communities in the western Alps. The effects of neighbor removal on the survival, aboveground biomass, and reproduction of five target species were tested at each of six experimental sites. Using biomass data, we calculated relative competitive index (RCI) and …

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Isolation And Characterization Of A Novel As(V)-Reducing Bacterium: Implications For Arsenic Mobilization And The Genus Desulfitobacterium, Allison Niggemyer, Stefan Spring, Erko Stackebrandt, Frank Rosenzweig Dec 2001

Isolation And Characterization Of A Novel As(V)-Reducing Bacterium: Implications For Arsenic Mobilization And The Genus Desulfitobacterium, Allison Niggemyer, Stefan Spring, Erko Stackebrandt, Frank Rosenzweig

Biological Sciences Faculty Publications

Dissimilatory arsenate-reducing bacteria have been implicated in the mobilization of arsenic from arsenic-enriched sediments. An As(V)-reducing bacterium, designated strain GBFH, was isolated from arsenic-contaminated sediments of Lake Coeur d'Alene, Idaho. Strain GBFH couples the oxidation of formate to the reduction of As(V) when formate is supplied as the sole carbon source and electron donor. Additionally, strain GBFH is capable of reducing As(V), Fe(III), Se(VI), Mn(IV) and a variety of oxidized sulfur species. 16S ribosomal DNA sequence comparisons reveal that strain GBFH is closely related to Desulfitobacterium hafniense DCB-2T and Desulfitobacterium frappieri PCP-1T. Comparative physiology demonstrates that D …

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Percent G+C Profiling Accurately Reveals Diet-Related Differences In The Gastrointestinal Microbial Community Of Broiler Chickens, Juha H. A. Apajalahti, Anu Kettunen, Michael R. Bedford, William E. Holben Dec 2001

Percent G+C Profiling Accurately Reveals Diet-Related Differences In The Gastrointestinal Microbial Community Of Broiler Chickens, Juha H. A. Apajalahti, Anu Kettunen, Michael R. Bedford, William E. Holben

Biological Sciences Faculty Publications

Broiler chickens from eight commercial farms in Southern Finland were analyzed for the structure of their gastrointestinal microbial community by a nonselective DNA-based method, percent G+C-based profiling. The bacteriological impact of the feed source and in-farm whole-wheat amendment of the diet was assessed by percent G+C profiling. Also, a phylogenetic 16S rRNA gene (rDNA)-based study was carried out to aid in interpretation of the percent G+C profiles. This survey showed that most of the 16S rDNA sequences found could not be assigned to any previously known bacterial genus or they represented an unknown species of one of the taxonomically heterogeneous …

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Swimming Mechanics And Behavior Of The Shallow-Water Brief Squid Lolliguncula Brevis, Ian K. Bartol, Mark R. Patterson, Roger Mann Nov 2001

Swimming Mechanics And Behavior Of The Shallow-Water Brief Squid Lolliguncula Brevis, Ian K. Bartol, Mark R. Patterson, Roger Mann

Biological Sciences Faculty Publications

Although squid are among the most versatile swimmers and rely on a unique locomotor system, little is known about the swimming mechanics and behavior of most squid, especially those that swim at low speeds in inshore waters. Shallow-water brief squid Lolliguncula brevis, ranging in size from 1.8 to 8.9 cm. in dorsal mantle length (DML), were placed in flumes and videotaped, and the data were analyzed using motion-analysis equipment. Flow visualization and force measurement experiments were also performed in water tunnels. Mean critical swimming speeds (Ucrit) ranged from 15.3 to 22.8 cm s-1, and mean …

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Structural And Functional Analysis Of Interhelical Interactions In The Human Immunodeficiency Virus Type 1 Gp41 Envelope Glycoprotein By Alanine-Scanning Mutagenesis, Min Lu, Marisa O. Stoller, Shilong Wang, Jie Liu, Melinda B. Fagan, Jack H. Nunberg Nov 2001

Structural And Functional Analysis Of Interhelical Interactions In The Human Immunodeficiency Virus Type 1 Gp41 Envelope Glycoprotein By Alanine-Scanning Mutagenesis, Min Lu, Marisa O. Stoller, Shilong Wang, Jie Liu, Melinda B. Fagan, Jack H. Nunberg

Biological Sciences Faculty Publications

Membrane fusion by human immunodeficiency virus type 1 (HIV-1) is promoted by the refolding of the viral envelope glycoprotein into a fusion-active conformation. The structure of the gp41 ectodomain core in its fusion-active state is a trimer of hairpins in which three antiparallel carboxyl-terminal helices pack into hydrophobic grooves on the surface of an amino-terminal trimeric coiled coil. In an effort to identify amino acid residues in these grooves that are critical for gp41 activation, we have used alanine-scanning mutagenesis to investigate the importance of individual side chains in determining the biophysical properties of the gp41 core and the membrane …

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The Standardized Fish Bioassay Procedure For Detecting And Culturing Actively Toxic Pfiesteria, Used By Two Reference Laboratories For Atlantic And Gulf Coast States, Joann M. Burkholder, Harold G. Marshall, David W. Seaborn, Nora J. Deamer-Melia Oct 2001

The Standardized Fish Bioassay Procedure For Detecting And Culturing Actively Toxic Pfiesteria, Used By Two Reference Laboratories For Atlantic And Gulf Coast States, Joann M. Burkholder, Harold G. Marshall, David W. Seaborn, Nora J. Deamer-Melia

Biological Sciences Faculty Publications

In the absence of purified standards of toxins from Pfiesteria species, appropriately conducted fish bioassays are the "gold standard" that must be used to detect toxic strains of Pfiesteria slop. from natural estuarine water or sediment samples and to culture actively toxic Pfiesteria. In this article, we describe the standardized steps of our fish bioassay as an abbreviated term for a procedure that includes two sets of trials with fish, following the Henle-Koch postulates modified for toxic rather than infectious agents. This procedure was developed in 1991, and has been refined over more than 12 years of experience in …

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Structure Of The Rgrgs Domain Of P115rhogef, Zhe Chen, Clark D. Wells, Paul C. Sternweis, Stephen R. Sprang Sep 2001

Structure Of The Rgrgs Domain Of P115rhogef, Zhe Chen, Clark D. Wells, Paul C. Sternweis, Stephen R. Sprang

Biological Sciences Faculty Publications

p115RhoGEF, a guanine nucleotide exchange factor for Rho GTPase, is also a GTPase activating protein (GAP) for G12 and G13 heterotrimeric Gα subunits. Near its N-terminus, p115RhoGEF contains a domain (rgRGS) with remote sequence identity to RGS (regulators of G protein signaling) domains. The rgRGS domain is necessary but not sufficient for the GAP activity of p115RhoGEF. The 1.9 Å resolution crystal structure of the rgRGS domain shows structural similarity to RGS domains but possesses a C-terminal extension that folds into a layer of helices that pack against the hydrophobic core of the domain. Mutagenesis experiments show that …

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Restoring Enriched Grasslands: Effects Of Mowing On Species Richness, Productivity, And Nitrogen Retention, John L. Maron, Robert L. Jefferies Aug 2001

Restoring Enriched Grasslands: Effects Of Mowing On Species Richness, Productivity, And Nitrogen Retention, John L. Maron, Robert L. Jefferies

Biological Sciences Faculty Publications

Species-rich grasslands that become enriched with nitrogen often suffer decreases in species richness, increases in plant biomass, and invasion by weedy exotic species. Suitable techniques to restore enriched grasslands and reestablish native communities are increasingly needed. Here we report results of a 5-yr experiment in enriched coastal prairie grasslands (Bodega Marine Reserve, Bodega Bay, California, USA), to determine the combined effects of mowing and biomass removal on total soil nitrogen, net rates of mineralization, nitrogen retention, and species richness and biomass. We mowed and removed plant biomass from plots in areas where the N-fixing shrub, bush lupine (Lupinus arboreus …

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Transduction By Phi Bb-1, A Bacteriophage Of Borrelia Burgdorferi, Christian H. Eggers, Betsy J. Kimmel, James L. Bono, Abdallah F. Elias, Patricia Rosa, D. Scott Samuels Aug 2001

Transduction By Phi Bb-1, A Bacteriophage Of Borrelia Burgdorferi, Christian H. Eggers, Betsy J. Kimmel, James L. Bono, Abdallah F. Elias, Patricia Rosa, D. Scott Samuels

Biological Sciences Faculty Publications

We previously described a bacteriophage of the Lyme disease agent Borrelia burgdorferi designated phi BB-1. This phage packages the host complement of the 32-kb circular plasmids (cp32s), a group of homologous molecules found throughout the genus Borrelia. To demonstrate the ability of phi BB-1 to package and transduce DNA, a kanamycin resistance cassette was inserted into a cloned fragment of phage DNA, and the resulting construct was transformed into B. burgdorferi CA-11.2A cells. The kan cassette recombined into a resident cp32 and was stably maintained. The cp32 containing the kan cassette was packaged by phi BB-1 released from this B. …

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Assembly Of Reca-Like Recombinases: Distinct Roles For Mediator Proteins In Mitosis And Meiosis, Stephen L. Gasior Jul 2001

Assembly Of Reca-Like Recombinases: Distinct Roles For Mediator Proteins In Mitosis And Meiosis, Stephen L. Gasior

Biological Sciences Faculty Publications

Members of the RecA family of recombinases from bacteriophage T4, Escherichia coli, yeast, and higher eukaryotes function in recombination as higher-order oligomers assembled on tracts of single-strand DNA (ssDNA). Biochemical studies have shown that assembly of recombinase involves accessory factors. These studies have identified a class of proteins, called recombination mediator proteins, that act by promoting assembly of recombinase on ssDNA tracts that are bound by ssDNA-binding protein (ssb). In the absence of mediators, ssb inhibits recombination reactions by competing with recombinase for DNA-binding sites. Here we briefly review mediated recombinase assembly and present results of new in vivo experiments. …

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Isoetes Mattaponica (Isoetaceae), A New Diploid Quillwort From Freshwater Tidal Marshes Of Virginia, Lytton John Musselman, W. Carl Taylor, Rebecca D. Bray Jul 2001

Isoetes Mattaponica (Isoetaceae), A New Diploid Quillwort From Freshwater Tidal Marshes Of Virginia, Lytton John Musselman, W. Carl Taylor, Rebecca D. Bray

Biological Sciences Faculty Publications

Isoetes mattaponica is a rare quillwort of freshwater tidal rivers of eastern Virginia with a somatic chromosome number of 2n = 22. Megaspores have low rugulate muri on both the proximal and distal surfaces; the girdle is broad. Microspores are echinate-spinose with ornamented spines. Isoetes mattaponica may be one of the parents of several polyploids in the Southeastern United States.

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Establishing A Direct Role For The Bartonella Bacilliformis Invasion-Associated Locus B (Ialb) Protein In Human Erythrocyte Parasitism, Sherry A. Coleman, Michael F. Minnick Jul 2001

Establishing A Direct Role For The Bartonella Bacilliformis Invasion-Associated Locus B (Ialb) Protein In Human Erythrocyte Parasitism, Sherry A. Coleman, Michael F. Minnick

Biological Sciences Faculty Publications

The invasion-associated locus A and B genes (ialAB) of Bartonella bacilliformis were previously shown to confer an erythrocyte-invasive phenotype upon Escherichia coli, indirectly implicating their role in virulence. We report the first direct demonstration of a role for ialB as a virulence factor in B, bacilliformis. The presence of a secretory signal sequence and amino acid sequence similarity to two known outer membrane proteins involved in virulence suggested that IalB was an outer membrane protein, To develop an antiserum for protein localization, the ialB gene was cloned in frame into an expression vector with a six-histidine tag and under control …

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C2 Domains From Different Ca2+ Signaling Pathways Display Functional And Mechanistic Diversity, E. A. Nalefski, M. A. Wisner, J. Z. Chen, S. R. Sprang, M. Fukuda, K. Mikoshiba, J. J. Falke Mar 2001

C2 Domains From Different Ca2+ Signaling Pathways Display Functional And Mechanistic Diversity, E. A. Nalefski, M. A. Wisner, J. Z. Chen, S. R. Sprang, M. Fukuda, K. Mikoshiba, J. J. Falke

Biological Sciences Faculty Publications

The ubiquitous C2 domain is a conserved Ca2+-triggered membrane-docking module that targets numerous signaling proteins to membrane surfaces where they regulate diverse processes critical for cell signaling. In this study, we quantitatively compared the equilibrium and kinetic parameters of C2 domains isolated from three functionally distinct signaling proteins: cytosolic phospholipase A2-α (cPLA2-α), protein kinase C-β (PKC-β), and synaptotagmin-IA (Syt-IA). The results show that equilibrium C2 domain docking to mixed phosphatidylcholine and phosphatidylserine membranes occurs at micromolar Ca2+ concentrations for the cPLA2-α C2 domain, but requires 3- and 10-fold higher Ca2+ …

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Experimental Model Of Human Body Louse Infection Using Green Fluorescent Protein-Expressing Bartonella Quintana, Pierre-Edouard Fournier, Michael F. Minnick, Hubert Lepidi, Eric Salvo, Didier Raoult Mar 2001

Experimental Model Of Human Body Louse Infection Using Green Fluorescent Protein-Expressing Bartonella Quintana, Pierre-Edouard Fournier, Michael F. Minnick, Hubert Lepidi, Eric Salvo, Didier Raoult

Biological Sciences Faculty Publications

A laboratory colony of human body lice was experimentally infected by feeding on rabbits made artificially bacteremic with a green fluorescent protein-expressing Bartonella quintana. B. quintana was detected in the gut and feces until death but not in the eggs. The life span of the lice was not modified. The rabbit model should provide valuable clues to the role of lice in the transmission of B. quintana.

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Antibody Binding And Neutralization Of Primary And T-Cell Line-Adapted Isolates Of Human Immunodeficiency Virus Type 1, Joanne York, Kathryn E. Follis, Meg Trahey, Phillipe N. Nyambi, Susan Zolla-Pazner, Jack H. Nunberg Mar 2001

Antibody Binding And Neutralization Of Primary And T-Cell Line-Adapted Isolates Of Human Immunodeficiency Virus Type 1, Joanne York, Kathryn E. Follis, Meg Trahey, Phillipe N. Nyambi, Susan Zolla-Pazner, Jack H. Nunberg

Biological Sciences Faculty Publications

The relative resistance of human immunodeficiency virus type 1 (HIV-1) primary isolates (PIs) to neutralization by a wide range of antibodies remains a theoretical and practical barrier to the development of an effective HIV vaccine. One model to account for the differential neutralization sensitivity between Pls and laboratory (or T-cell line-adapted [TCLA]) strains of HN suggests that the envelope protein (Env) complex is made more accessible to antibody binding as a consequence of adaptation to growth in established cell lines. Here, we revisit this question using genetically related PI and TCLA viruses and molecularly cloned env genes. By using complementary …

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Life-History Evolution In Guppies. Vii. The Comparative Ecology Of High- And Low-Predation Environments, David Reznick, Mark J. Butler Iv, Helen Rodd Feb 2001

Life-History Evolution In Guppies. Vii. The Comparative Ecology Of High- And Low-Predation Environments, David Reznick, Mark J. Butler Iv, Helen Rodd

Biological Sciences Faculty Publications

Prior research has demonstrated a strong association between the species of predators that co-occur with guppies and the evolution of guppy life histories. The evolution of these differences in life histories has been attributed to the higher mortality rates experienced by guppies in high-predation environments. Here, we evaluate whether there might be indirect effects of predation on the evolution of life-history patterns and whether there are environmental differences that are correlated with predation. To do so, we quantified features of the physical and chemical environment and the population biology of guppies from seven high-and low-predation localities. We found that high-predation …

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Acclimation To Hypoxia Increases Survival Time Of Zebrafish, Danio Rerio, During Lethal Hypoxia, Bernard B. Rees, F Sudradjat, J W. Love Jan 2001

Acclimation To Hypoxia Increases Survival Time Of Zebrafish, Danio Rerio, During Lethal Hypoxia, Bernard B. Rees, F Sudradjat, J W. Love

Biological Sciences Faculty Publications

Survivorship of zebrafish, Danio rerio, was measured during lethal hypoxic stress after pretreatment in water at either ambient oxygen or at a lowered, but nonlethal, level of oxygen. Acclimation to nonlethal hypoxia (pO2 @ 15 Torr; ca. 10% air-saturation) for 48 hr significantly extended survival time during more severe hypoxia (pO2 @ 8 Torr; ca. 5% air-saturation) compared to survival of individuals with no prior hypoxic exposure. The magnitude of the acclimation effect depended upon the sex of the fish: hypoxia pretreatment increased the survival times of males by a factor of approximately 9 and that of females by a …

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Aerobic Respiratory Costs Of Swimming In The Negatively Buoyant Brief Squid Lolliguncula Brevis, Ian K. Bartol, Roger Mann, Mark R. Patterson Jan 2001

Aerobic Respiratory Costs Of Swimming In The Negatively Buoyant Brief Squid Lolliguncula Brevis, Ian K. Bartol, Roger Mann, Mark R. Patterson

Biological Sciences Faculty Publications

Because of the inherent inefficiency of jet propulsion, squid are considered to be at a competitive disadvantage compared with fishes, which generally depend on forms of undulatory/oscillatory locomotion. Some squid, such as the brief squid Lolliguncula brevis, swim at low speeds in shallow-water complex environments, relying heavily on fin activity. Consequently, their swimming costs may be lower than those of the faster, more pelagic squid studied previously and competitive with those of ecologically relevant fishes. To examine aerobic respiratory swimming Costs, O2 consumption rates were measured for L. brevis of various sizes (2-9 cm. dorsal mantle length, DML) …

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Identification Of A Defensin From The Hemolymph Of The American Dog Tick, Dermacentor Variabilis, Robert Johns, Daniel E. Sonenshine, Wayne L. Hynes Jan 2001

Identification Of A Defensin From The Hemolymph Of The American Dog Tick, Dermacentor Variabilis, Robert Johns, Daniel E. Sonenshine, Wayne L. Hynes

Biological Sciences Faculty Publications

Hemolymph from partially fed virgin Dermacentor variabilis females was collected following Borrelia burgdorferi challenge and assayed for antimicrobial activity against Bacillus subtilis and B. burgdorferi. A small inducible cationic peptide was identified by SDS-PAGE in the hemolymph of these ticks as early as 1h post challenge. Following purification by a three-step procedure involving sequential SepPak elution, reversed phase high performance liquid chromatography (RP-HPLC) and gel electrophoresis, the yield of the active peptide was approximately 0.1% of the total protein in the hemolymph plasma. The molecular weight, 4.2kDa, was determined by MALDI-TOF mass spectrometry. N-terminal sequencing by the Edman degradation …

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Trachelomonas Spp. And Other Euglenophyceae Taxa In A Southeastern Virginia Lake, Harold G. Marshall Jan 2001

Trachelomonas Spp. And Other Euglenophyceae Taxa In A Southeastern Virginia Lake, Harold G. Marshall

Biological Sciences Faculty Publications

Trachelomonas species from Lake Kilby, a reservoir lake in southeastern Virginia are described with supportive electron micrographs. The most abundant Trachelomonas species were T. hispida and T. volvocina. Other members of the Euglenophyceae occurring in this lake are identified.

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Classification And Identification Of Pfiesteria And Pfiesteria-Like Species, Karen Steidinger, Jan Landsberg, R. William Richardson, Earnest Truby, Barbara Blakesley, Paula Scott, Patricia Tester, Torstein Tengs, Patrice Mason, Stever Morton, David Seaborn, Wayne Litaker, Kimberly Reece, David Oldach, Leonard Haas, Gerardo Vasta Jan 2001

Classification And Identification Of Pfiesteria And Pfiesteria-Like Species, Karen Steidinger, Jan Landsberg, R. William Richardson, Earnest Truby, Barbara Blakesley, Paula Scott, Patricia Tester, Torstein Tengs, Patrice Mason, Stever Morton, David Seaborn, Wayne Litaker, Kimberly Reece, David Oldach, Leonard Haas, Gerardo Vasta

Biological Sciences Faculty Publications

Dinoflagellates can be classified both botanically and zoologically; however, they are typically put in the botanical division Pyrrhophyta. As a group they appear most related to the protistan ciliates and apicomplexans at the ultrastructure level. Within the Pyrrhophyta are both unarmored and armored forms of the dominant, motile flagellated stage. Unarmored dinoflagellates do not have thecal or wall plates arranged in specific series, whereas armored species have plates that vary in thickness but are specific in number and arrangement. In armored dinoflagellates, the plate pattern and tabulation is a diagnostic character at the family, subfamily, and even genus levels. In …

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Development Of Microsatellite Multiplexes For Wild Goats Using Primers Designed From Domestic Bovidae, Celia Maudet, Gordon Luikart, Pierre Taberlet Jan 2001

Development Of Microsatellite Multiplexes For Wild Goats Using Primers Designed From Domestic Bovidae, Celia Maudet, Gordon Luikart, Pierre Taberlet

Biological Sciences Faculty Publications

Many wild goat taxa (Capra spp.) are endangered and would benefit from the availability of molecular tools that are useful for population management and conservation. We developed microsatellite DNA markers useful in all wild goat species, by using a cross-species amplification approach. Seventy-five microsatellite primer pairs designed from domestic cattle (Bos taurus), sheep (Ovis aries) and goat (Capra hircus) were tested oil three distantly related Capra species: C. ibex ibex, C. [i.] sibirica, and C. pyrenaica. On average, 90% of the domestic ungulate primers amplified a microsatellite PCR product in the …

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The 6th International Conference And Workshop On Lobster Biology And Management: An Introduction, Mark J. Butler Iv Jan 2001

The 6th International Conference And Workshop On Lobster Biology And Management: An Introduction, Mark J. Butler Iv

Biological Sciences Faculty Publications

Every three years or so, the International Conference and Workshop on Lobster Biology and Management (ICWL) brings together lobster scientists, fishery managers, and industry representatives from around the world for a week of scientific presentations, workshops, and discussions on lobster biology and management. The first ICWL was held in Perth, Australia, in January 1977. Its purpose was to bring together a small group of lobster researchers from the USA and Australia to discuss common issues and themes. That initial workshop spawned a continuing series of meetings that have become the international lobster conference for scientists—the equivalent of an international congress …

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Tick Immunity To Microbial Infections: Control Of Representative Bacteria In The Hard Tick Dermacentor Variabilis (Acari: Ixodidae), Robert Johns, Shane Ceraul, Daniel E. Sonenshine, Wayne L. Hynes Jan 2001

Tick Immunity To Microbial Infections: Control Of Representative Bacteria In The Hard Tick Dermacentor Variabilis (Acari: Ixodidae), Robert Johns, Shane Ceraul, Daniel E. Sonenshine, Wayne L. Hynes

Biological Sciences Faculty Publications

No abstract provided.

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Contrasts In Tick Innate Immune Responses To Borrelia Burgdorferi Challenge: Immuno-Tolerance In Ixodes Scapularis Versus Immunocompetence In Dermacentor Variabilis (Acari: Ixodidae)., Robert Johns, Jun Ohnishi, Anne Broadwater, Daniel E. Sonenshine, Aravinda M. Desilva, Wayne L. Hynes Jan 2001

Contrasts In Tick Innate Immune Responses To Borrelia Burgdorferi Challenge: Immuno-Tolerance In Ixodes Scapularis Versus Immunocompetence In Dermacentor Variabilis (Acari: Ixodidae)., Robert Johns, Jun Ohnishi, Anne Broadwater, Daniel E. Sonenshine, Aravinda M. Desilva, Wayne L. Hynes

Biological Sciences Faculty Publications

The blacklegged tick, Ixodes scapularis Say, transmits the Lyme disease spirochete (Borrelia burgdorferi), whereas the American dog tick, Dermacentor variabilis (Say), is unable to transmit the bacterium. We compared the innate immune response of these ticks against spirochetes directly inoculated into the hemocoel cavity of ticks. In I. scapularis, some Borrelia were found associated with hemocytes, while numerous other spiral-shaped, intact bacteria remained free in the hemolymph. In contrast, in D. variabilis only remnants of the bacteria were evident in the hemolymph, indicating lysis; intact spirochetes were rare. Spirochetes were observed bound to or within the organs …

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The Genus Striga (Scrophulariaceae) In Africa, Kamal I. Mohamed, Lytton John Musselman, Charles R. Riches Jan 2001

The Genus Striga (Scrophulariaceae) In Africa, Kamal I. Mohamed, Lytton John Musselman, Charles R. Riches

Biological Sciences Faculty Publications

Twenty-eight species and six subspecies of the hemiparasitic genus Striga Lour., witchweed, occur in Africa. Twenty-two species are endemic. Witchweeds occur throughout the continent with greatest diversity in the grasslands and savannas north of the equator. Striga gesnerioides (Willd.) Vatke and S. hermonthica (Del.) Benth. have developed host-specific strains that may have distinct morphotypes. me accord these no formal taxonomic status. Striga hermonthica and S. asiatica (L.) Kuntze, limited to agroecosystems, may be recently derived from non-ruderal species. Striga hirsuta Benth. and S. lutea Lour., sometimes treated as conspecific with S. asiatica, are recognized as distinct species restricted …

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Twenty-Five Years Of Population Fluctuations Of Microtus Ochrogaster And M-Pennsylvanicus In Three Habitats In East-Central Illinois, Lowell L. Getz, Joyce E. Hofmann, Betty Mcguire, Thomas W. Dolan Iii Jan 2001

Twenty-Five Years Of Population Fluctuations Of Microtus Ochrogaster And M-Pennsylvanicus In Three Habitats In East-Central Illinois, Lowell L. Getz, Joyce E. Hofmann, Betty Mcguire, Thomas W. Dolan Iii

Biological Sciences Faculty Publications

Populations of 2 species of arvicoline rodents, the prairie vole (Microtus ochrogaster) and meadow vole (M. pennsylvanicus), were monitored monthly in alfalfa, bluegrass, and tallgrass prairie habitats in east-central Illinois from 1972 through 1997. Alfalfa provides very highquality preferred food and poor vegetative cover for both vole species, whereas bluegrass provides intermediate food and vegetative cover. Preferred food resources were very low, especially for M. ochrogaster, and vegetative cover was very dense in tallgrass prairie. Maximum and mean population densities of M. ochrogaster were highest in alfalfa, intermediate in bluegrass, and lowest in tallgrass prairie. …

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Infection And Transovarial Transmission Of Rickettsiae In Dermacentor Variabilis Acquired By Artificial Feeding, K. R. Macaluso, Daniel E. Sonenshine, Shane M. Ceraul, A. F. Azad Jan 2001

Infection And Transovarial Transmission Of Rickettsiae In Dermacentor Variabilis Acquired By Artificial Feeding, K. R. Macaluso, Daniel E. Sonenshine, Shane M. Ceraul, A. F. Azad

Biological Sciences Faculty Publications

In this study we examined the efficiency of an in vitro feeding technique using glass microcapillaries as a method of establishing rickettsiae-infected lines of ticks. To quantify the volume ingested by ticks during microcapillary feeding, the incorporation of radiolabeled amino acids in tick gut and hemolymph was calculated. Fifteen of 18 ticks consumed between 0.06 μl and 6.77μl. However, ingestion of fluid was not correlated to weight gain during capillary feeding. Uninfected and partially fed laboratory-reared female Dermacentor variabilis ticks were exposed to either Rickettsia montana- or Rickettsia rhipicephali-infected Vero cells via microcapillary tubes, returned to rabbit hosts, …

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