Digital Commons Network^™

Biomimetic Actuators: Where Technology And Cell Biology Merge [Review Article], Michael Knoblauch, Winfried Peters

Winfried S. Peters

Photo- And Electropatterning Of Hydrogel-Encapsulated Living Cell Arrays, Dirk Albrecht, Valerie Tsang, Robert Sah, Sangeeta Bhatia

Dirk R. Albrecht

Living cells have the potential to serve as sensors, naturally integrating the response to stimuli to generate predictions about cell fate (e.g., differentiation, migration, proliferation, apoptosis). Miniaturized arrays of living cells further offer the capability to interrogate many cells in parallel and thereby enable high-throughput and/or combinatorial assays. However, the interface between living cells and synthetic chip platforms is a critical one wherein the cellular phenotype must be preserved to generate useful signals. While some cell types retain tissue-specific features on a flat (2-D) surface, it has become increasingly apparent that a 3-D physical environment will be required for others. …

Evidence For And Characterization Of Ca2+ Binding To The Catalytic Region Of Arabidopsis Thaliana Phospholipase Dβ, Xuemin Wang

Xuemin (Sam) Wang

Embryonic Expression Of Pre-Initiation Dna Replication Factors In Xenopus Laevis, Brian Walter, Jonathan Henry

Brian Walter

We examined the expression of various DNA replication factors, including: cdc45, the factors of the GINS heterotetramer (Sld5, Psf1, Psf2, Psf3), and PCNA, in Xenopus laevis during embryonic development via whole mount in situ hybridization. For the most part, these factors were expressed in similar patterns, with some subtle variations, throughout development within the anterior CNS, pharyngeal arches, and various placodes. More significant variations were also observed, including expression of only Psf1 and Psf2 in the pronephros and unique Psf2 expression in the somitic mesoderm. Overall, these results suggest that common regulatory mechanisms are involved in the transcriptional deployment of …

Is There An Antipredator Blood-Squirting Defense In The Bull Horned Lizard, Phrynosoma Taurus?, George Middendorf

George Middendorf

No abstract provided.

Germination Of Silene Regia Seeds From Four Sites In Lawrence County, Illinois, Following Scarification Or Stratification, Nicolette L. Flocca, Janice M. Coons, Henry R. Owen, Brian J. Fischer, Bob E. Edgin

Henry R. Owen

Silene regia Sims is an endangered prairie forb in Illinois where small isolated colonies are scattered. In La·wrence County, two sites (Allison Prairie and Chauncey Marsh) have fewer plants (6-23) than two other sites (Cmmty Road and Cemetery) with 26-45 plants. Information on seed germination in these isolated colonies is needed. Our goal was to evaluate seed germination of S. regia from colonies in Lawrence County, illinois. S. regia fruits were collected from these four sites on August 9 and 19, 1999. Seeds were scarified by cutting the seed coat, or they were stratified at 2 C for 12 or …

Renesting Decisions And Annual Fecundity Of Female Dickcissels (Spiza Americana) In Illinois, Jeffrey W. Walk, Kevin Wentworth, Eric L. Kershner, Eric K. Bollinger, Richard E. Warner

Eric K. Bollinger

ABSTRACT.-Renesting decisions and annual fecundity are crucial for interpreting other demographic information, yet are infrequently reported. We used radiotelemetry to monitor female Dickcissels (Spiza americana) throughout the 1999 and 2000 breeding seasons in southeastern Illinois. Overall fecundity (regardless of whether females remained in the study area throughout the breeding season) was 0.61 ± 0.13 female fledglings per year. Of females that remained within the study area, 94% fledged young (1.25 ± 0.15 female fledglings per year). Most females (62%) that experienced nest failure emigrated from the study area (moved >10 km) in 2.8 ± 0.6 days; others (36%) initiated subsequent …

A Spiroplasma Associated With Tremor Disease In The Chinese Mitten Crab (Eriocheir Sinensis), Wen Wang, Bohai Wen, Gail E. Gasparich, Ningning Zhu, Liwen Rong, Jianxiu Chen, Zaikuan Xu

Gail Gasparich

Size And Organic Content Of Eggs Of Marine Annelids, And The Underestimation Of Egg Energy Content By Dichromate Oxidation, William Jaeckle, Bruno Pernet

William Jaeckle

Dichromate oxidation is a simple technique that is often used to estimate the energy content of eggs in studies of marine invertebrate life histories (1). We used this method to measure the energy contents of the eggs of 12 species of marine annelids. In combination with measures of egg ash-free dry weight (AFDW), these data yielded estimates of AFDW-specific energy density that were mostly lower than the average weight-specific energy density of carbohydrates. This seemed unlikely to be correct, as invertebrate eggs typically contain little carbohydrate and instead are composed primarily of energy-dense protein and lipid (1, 2). After validating …

Osedax: Bone-Eating Marine Worms With Dwarf Males, G W. Rouse, Shana K. Goffredi, R C. Vrijenhoek

Shana Goffredi

We describe a new genus, Osedax, and two new species of annelids with females that consume the bones of dead whales via ramifying roots. Molecular and morphological evidence revealed that Osedax belongs to the Siboglinidae, which includes pogonophoran and vestimentiferan worms from deep-sea vents, seeps, and anoxic basins. Osedax has skewed sex ratios with numerous dwarf (paedomorphic) males that live in the tubes of females. DNA sequences reveal that the two Osedax species diverged about 42 million years ago and currently maintain large populations ranging from 105 to 106 adult females.

Vibrio Parahaemolyticus And V. Harveyi Cause Detachment Of The Epithelium From The Midgut Trunk Of The Penaeid Shrimp, Sicyonia Ingentis., Gary G. Martin, Nicole Rubin, Erica Swanson

Gary Martin

Shrimp Sicyonia ingentis were either injected with Vibrio parahaemolyticus (104 CFU) or V. harveyi (106 CFU) or immersed in ASW containing either species at 105 CFU ml-1. These densities were shown in preliminary experiments to kill approximately half the population by 7 d. On Day 7, surviving shrimp were classified as either diseased or apparently healthy, and their midgut trunks (MGT) were examined by light and electron microscopy. All shrimp immersed in ASW containing either species of Vibrio showed detachment of the epithelium in the MGT. In shrimp injected with either species of Vibrio, epithelial detachment was common in diseased …

Gender-Selective Patterns Of Aggressive Behavior In Drosophila Melanogaster, Steven P. Nilsen, Yick-Bun Chan, Robert Huber, Edward A. Kravitz

Robert Huber

Complex behaviors, such as aggression, are comprised of distinct stereospecific behavioral patterns (modules). How such patterns get wired into nervous systems remains unknown. Recently, we reported on a quantitative analysis of fighting behavior in male flies of the common Canton-S strain of Drosophila melanogaster. Here, we report a similar analysis of fighting behavior in females of the same species. Fights were carried out between pairs of virgin and pairs of mated females in competition for a yeast resource. Each fight was videotaped and analyzed by using transition matrices and Markov chain analyses. We observe only small difference in fighting intensity …

Responses Of Nesting Bobolinks (Dolichonyx Oryzivorus) To Habitat Edges, Eric K. Bollinger, Thomas A. Gavin

Eric K. Bollinger

T.-Avoidance of habitat edges may be contributing to reduced densities of grass- land birds in small habitat patches. Nest densities for grassland-nesting Bobolinks (Dolichonyx oryzivorus) were much lower than expected within 25 m of forest edges at three sites in New York, and that pattern ("edge avoidance") extended to 100 m at one site. Nests located within 50 m of forest or wooded hedgerow edges had lower daily survival rates, compared with nests >100 m from any habitat edge. Bobolinks tended to move away from forest edges when renest- ing after nest failure; that pattern was especially evident in females …

Responses Of Kit Foxes (Vulpes Macrotis) To Antipredator Blood-Squirting And Blood Of Texas Horned Lizards (Phrynosoma Cornutum), Wade Sherbrooke, George Middendorf, M E. Douglas

George Middendorf

Attracting Antagonists: Does Floral Nectar Increase Leaf Herbivory?, Lynn Adler, Judith L. Bronstein

Lynn Adler

Traits that are attractive to mutualists may also attract antagonists, resulting in conflicting selection pressures. Here we develop the idea that increased floral nectar production can, in some cases, increase herbivory. In these situations, selection for increased nectar production to attract pollinators may be constrained by a linked cost of herbivore attraction. In support of this hypothesis, we report that experimentally supplementing nectar rewards in Datura stramonium led to increased oviposition by Manduca sexta, a sphingid moth that pollinates flowers, but whose larvae feed on leaf tissue. We speculate that nectar composition may provide information about plant nutritional status or …

Speciation In The Central American Seaway: The Importance Of Taxon Sampling In The Identification Of Trans-Isthmian Geminate Pairs, Matthew T. Craig, Philip A. Hastings, Daniel J. Pondella Ii

Daniel Pondella

Aim  To create a molecular phylogenetic hypothesis for the closely related serranid genera Alphestes Bloch and Schneider and Dermatolepis Gill and assess the role of the Panamanian Isthmus in speciation within these reef fishes. Location  Tropical eastern Pacific, Caribbean, and Indian Oceans. Methods  Sequence data from one nuclear (TMO-4C4) and three mitochondrial genes (16S, 12S, and cytochrome b) were used in maximum parsimony and maximum likelihood analyses. Results  Here we show that previously hypothesized trans-isthmian geminate species are not each other's closest living relatives. Species of Alphestes Bloch and Schneider in the eastern Pacific are sister taxa indicating post-closure speciation. …

Food Based Approaches For A Healthy Nutrition In Africa, Mamoudou Hama Dicko

Pr. Mamoudou H. DICKO, PhD

The latest estimates of the FAO demonstrate the problems of the fight against hunger. These problems are manifested by the ever-increasing number of chronically undernourished people worldwide. Their numbers during the 1999-2001 period were estimated at about 840 million of which 798 million live in developing countries. Sub-Saharan Africa alone represented 198 million of those. In this part of Africa the prevalence of undernourishment ranges from 5-34%, causing growth retardation and insufficient weight gain among one third of the children under five years of age and resulting in a mortality of 5-15% among these children. Malnutrition resulting from undernourishment is …

Synergistic And Antagonistic Roles Of The Sonic Hedgehog N- And C-Terminal Lipids, Jianchi Feng, Bryan White, Oksana V. Tyurina, Burcu Guner, Theresa Larson, Hae Young Lee, Rolf O. Karlstrom, Jhumku D. Kohtz

Rolf O Karlstrom

The Shh protein contains both N-terminal and C-terminal lipids. The functional redundancy of these lipid moieties is presently unclear. Here, we compare the relative roles of the N- and C-terminal lipids in early rat striatal neuronal differentiation, membrane association and multimerization, and ventralizing activity in the zebrafish forebrain. We show that these lipid act synergistically in cell tethering and the formation of a large (L) multimer (669 kDa). However, the C-terminal lipid antagonizes the rat striatal neuronal differentiation-inducing activity of the N-terminal lipid. In addition, multimerization is required but not sufficient for the differentiation-inducing activity. Based on the presence of …

A Regulatory Code For Neurogenic Gene Expression In The Drosophila Embryo, Michele Markstein, Robert Zinzen, Peter Markstein, Ka Ping Yee, Albert Erives, Angela Stathopoulos, Michael Levine

Michele Markstein

Bioinformatics methods have identified enhancers that mediate restricted expression in the Drosophila embryo. However, only a small fraction of the predicted enhancers actually work when tested in vivo. In the present study, co-regulated neurogenic enhancers that are activated by intermediate levels of the Dorsal regulatory gradient are shown to contain several shared sequence motifs. These motifs permitted the identification of new neurogenic enhancers with high precision: five out of seven predicted enhancers direct restricted expression within ventral regions of the neurogenic ectoderm. Mutations in some of the shared motifs disrupt enhancer function, and evidence is presented that the Twist and …

Amebiasis And Comparison Of Microscopy To Elisa Technique In Detection Of Entamoeba Histolytica And Entamoeba Dispar, Clarence Lee

Clarence Lee

Forisomes, A Novel Type Of Ca2+-Dependent Contractile Protein Motor [Review Article], Michael Knoblauch, Winfried Peters

Winfried S. Peters

Strouhal Numbers And Optimization Of Swimming By Odontocete Cetaceans, J J. Rohr, Frank E. Fish

Frank E. Fish

Swimming efficiencies of fish and cetaceans have been related to a certain synchrony between stroke cycle frequency, peak-to-peak tail/fluke amplitude and mean swimming speed. These kinematic parameters form a non-dimensional wake parameter, referred to as a Stroulial number, which for the range between 0.20 and 0.40 has been associated with enhanced swimming efficiency for fish and cetaceans. Yet to date there has been no direct experimental substantiation of what Strouhal numbers are preferred by swimming cetaceans. To address this lack of data, a total of 248 Stroubal numbers were calculated for the captive odontocete cetaceans Tursiops truncatus, Pseudorca crassidens, Orcinus …

Expression Of Haper1 And Habmal1 In Syrian Hamsters: Heterogeneity Of Transcripts And Oscillations In The Periphery, Eric L. Bittman, Yanhong Tong, Hongnian Guo, Judy Mckinley Brewer, Alexamder S. Bois

Eric L. Bittman

The molecular biology of circadian rhythms has been extensively studied in mice, and the widespread expression of canonical circadian clock genes in peripheral organs is well established in this species. In contrast, much less information about the peripheral expression of haPer1, haPer2, and haBmal1 is available in Syrian hamsters despite the fact that this species is widely used for studies of circadian organization and photoperiodic responses. Furthermore, examination of oscillating expression of these genes in mouse testis has generated discrepant results, and little is known about gonadal expression of haPer1 and haBmal1 or their environmental control. To address these questions, …

Inheritance Of Trunk Banding In The Tetra (Gymnocorymbus Ternetzi Characidae), Jack Frankel

Jack Frankel

Molecular Profiling: Gene Expression Reveals Discrete Phases Of Lens Induction And Development In Xenopus Laevis, Brian Walter, Yimin Tian, Amy Garlisch, Maria Carinato, Matthew Elkins, Adam Wolfe, Jonathan Schaefer, Kimberly Perry, Jonathan Henry

Brian Walter

No abstract provided.

Decreased Expression Of Cu–Zn Superoxide Dismutase 1 In Ants With Extreme Lifespan, Joel D. Parker, Karen M. Parker, Barbara H. Sohal, Rajindar S. Sohal, Laurent Keller

Joel D Parker

Reactive oxygen species, the by-products of oxidative energy metabolism, are considered a main proximate cause of aging. Accordingly, overexpression of the enzyme Cu–Zn superoxide dismutase 1 (SOD1) can lengthen lifespan of Drosophila melanogaster in the laboratory. However, the role of SOD1 as a main determinant of lifespan has been challenged on the grounds that overexpression might be effective only in compromised genetic backgrounds. Moreover, interspecific comparisons show lower levels of antioxidant activities in longer-lived species, suggesting that life-span extension may evolve through less reactive oxygen species generation from the mitochondria rather than higher expression of SOD1. The tremendous variation in …

Using Math In Cell Biology How Do Calcium Channels Work?, Borbala Mazzag

Borbala Mazzag

No abstract provided.

Mer1p Is A Modular Splicing Factor Whose Function Depends On The Conserved U2 Snrnp Protein Snu17p, Marc Spingola, Javier Armisen, Manuel Ares

Marc Spingola

Restoration Ecology: The Challenge Of Social Values And Expectations. (Forum), Mark Davis, Lawrence B. Slobodkin

Mark Davis

No abstract provided.

Ethiopian Soils Harbor Natural Populations Of Rhizobia That Form Symbioses With Common Bean (Phaseolus Vulgaris L.), Serawit Kassa, Desta Beyene, Franklin Ampy, Amha Asseffa, Tadesse Gebremedhin, Peter Van Berkum

Franklin Ampy