Life Sciences Commons^™

Concise Review: Dendritic Cell Development In The Context Of The Spleen Microenvironment, Jonathan Tan, Helen O'Neill

Jonathan Tan

The dendritic cell (DC) population in spleen comprises a mixture of cells including endogenous DC progenitors, DC precursors migrating in from blood and bone marrow, and DC in different states of differentiation and activation. A role for different microenvironments in supporting the dynamic development of murine DC of different types or lineages is considered here. Recent evidence for production of DC dependent on splenic stromal cells is reviewed in the light of evidence that cell production is dependent on cells comprising an endothelial niche in spleen. The possibility that self-renewing progenitors in spleen give rise to DC with tolerogenic or …

Non-Standard Sources In A Standardized World: Responsible Practice And Ethics Of Acquiring Turtle Specimens For Scientific Use, Edgar Lehr, Russell Burke, Linda Ford, Steve Mockford, Peter Pritchard, Jose Rosado, Darrell Senneke, Bryan Stuart

Edgar Lehr

No abstract provided.

Producer-Scrounger Roles And Joining Based On Dominance In A Free-Living Group Of Mexican Jays (Aphelocoma Ultramarina), John Mccormack, Piotr Jablonski, Jerram Brown

John E. McCormack

While foraging, animals often exploit group members to obtain food. One way to describe this behaviour is with the producer-scrounger (PS) model, where scroungers use social interaction to obtain food discovered by producers. Mexican jays (Aphelocoma ultramarina) are a groupforaging species with a linear dominance hierarchy. We studied interactions in a free-living foraging group to determine (1) if foraging interactions can be explained with the PS model, (2) if these roles are consistent and (3) if dominance or relatedness affects joining frequency. We recorded board-flipping, eating, and joining events during sets of feeding trials. We show that Mexican jays use …

Recent Postglacial Range Expansion Drives The Rapid Diversification Of A Songbird Lineage In The Genus Junco, Borja Milá, John Mccormack, Gabriela Castañeda, Robert Wayne, Thomas Smith

John E. McCormack

Pleistocene glacial cycles are thought to have played a major role in the diversification of temperate and boreal species of North American birds. Given that coalescence times between sister taxa typically range from 0.1 to 2.0 Myr, it has been assumed that diversification occurred as populations were isolated in refugia over long periods of time, probably spanning one to several full glacial cycles. In contrast, the rapid postglacial range expansions and recolonization of northern latitudes following glacial maxima have received less attention as potential promoters of speciation. Here we report a case of extremely rapid diversification in the songbird genus …

Looking Up From The Gutter: Pop-Culture And Philosophy, Stephen Asma

Stephen T Asma

No abstract provided.

Life History And Courtship Behavior Of Black Perch, Embiotoca Jacksoni (Teleostomi: Embiotocidae), From Southern California, Bridgette Froeschke, Larry Allen, Daniel Pondella

Daniel Pondella

The black perch, Embiotoca jacksoni Agassiz, 1853, is a common reef fish associated with nearshore marine habitats of California, with the majority of the population occurring within the Southern California Bight. Black perch were collected throughout southern California from Santa Barbara to Carlsbad, including Santa Catalina Island, to determine their physical characteristics, growth, sex ratio, periodicity of reproduction, and length of gestation. Courtship observations were conducted using scuba along the King Harbor Breakwater in Redondo Beach, California, from January 2004 to December 2005 to verify periodicity of courting and associated reproductive behaviors. Specimens captured ranged from 75 to 220 mm …

The Functional Role Of Cysteine Residues For C-Abl Kinase Activity., Amanda Leonberg, Yuh-Cherng Chai

Yuh-Cherng Chai

S-glutathionylation, the formation of mixed disulfides of glutathione with cysteine residues of proteins, is a broadly observed physiological modification that occurs in response to oxidative stress. Since cysteine residues are particularly susceptible to oxidative modification by reactive oxygen species, S-glutathionylation can protect proteins from irreversible oxidation. In this study, we show that the kinase activity of the non-receptor tyrosine kinase c-Abl is inhibited by in vitro thiol modification; specifically, the cysteine residues of c-Abl are modified by S-glutathionylation and by thiol alkylating agents such as 4-acetamido-4′-maleimidylstilbene-2,2′-disulfonic acid and N-ethylmaleimide. Modification of cysteine residues of c-Abl tyrosine kinase using glutathione disulfide …

Bactericidal Efficacy Of Liposomal Aminoglycosides Against Burkholderia Cenocepacia, Ali Azghani

Ali Azghani

Structure And Function Of Haemocytes In Two Marine Gastropods, Megathura Crenulata And Aplysia Californica., Gary Martin, Christopher Oates, Heather Tousignant, Heather Crabtree, Rachel Yamakawa

Gary Martin

Aplysia californica is an important mollusc for neurobiological research and Megathura crenulata is becoming valuable as the source of keyhole limpet haemocyanin (KLH) which shows promise in treating cancer, allergy and immunosuppression. The culture of these animals provides opportunities to assess their physiological responses to stress and disease. Molluscan haemocytes are known to be involved in a variety of physiological responses, yet the haemocytes of this opisthobranch and vetigastropod have not been characterized. The purpose of this study is to describe the morphology of these cells and summarize their functions based on a suite of assays previously developed on other …

Tailed Forisomes Of Canavalia Gladiata: A New Model To Study Ca2+-Driven Protein Contractility, Winfried Peters, Michael Knoblauch, Stephen Warmann, Reinhard Schnetter, Amy Shen, William Pickard

Winfried S. Peters

Frogs Of The Genus Eleutherodactylus (Leptodactyl Idae) In The Cordillera Occidental In Peru With Descriptions Of Three New Species, Edgar Lehr, William E. Duellman

Edgar Lehr

Three new species of Eleutherodactylus are described from the Rio Zana Valley in the Pacific versant of the Cordillera Occidental in the Departamento de Cajamarca, Peru. One of the species is a member of the Eleutherodactylus conspicillatus Group, and two are members of the Eleutherodactylus unstrigatus Group.We recognize 15 species of Eleutherodactylus in the Cordillera Occidental; 10 of these species are reported for the first time from the Cordillera Occidental. Four of these species are shared with the Cordillera Occidental in Ecuador, and five are shared with the Cordillera de Huancabamba in northern Peru.

Multiphase Electropatterning Of Cells And Biomaterials, Dirk Albrecht, Gregory Underhill, Avital Mendelson§, Sangeeta Bhatia

Dirk R. Albrecht

Tissues formed by cells encapsulated in hydrogels have uses in biotechnology, cell-based assays, and tissue engineering. We have previously presented a 3D micropatterning technique that rapidly localizes live cells within hydrogels using dielectrophoretic (DEP) forces, and have demonstrated the ability to modulate tissue function through the control of microscale cell architecture. A limitation of this method is the requirement that a single biomaterial must simultaneously harbor biological properties that support cell survival and function and material properties that permit efficient dielectrophoretic patterning. Here, we resolve this issue by forming multiphase tissues consisting of microscale tissue sub-units in a ‘local phase’ …

Transition-State Variation In Human, Bovine, And Plasmodium Falciparum Adenosine Deaminases, Minkui Lou, Vipender Singh, Erika Taylor, Vern Schramm

Erika A. Taylor, Ph.D.

Adenosine deaminases (ADAs) from human, bovine, and Plasmodium falciparum sources were analyzed by kinetic isotope effects (KIEs) and shown to have distinct but related transition states. Human adenosine deaminase (HsADA) is present in most mammalian cells and is involved in B- and T-cell development. The ADA from Plasmodium falciparum (PfADA) is essential in this purine auxotroph, and its inhibition is expected to have therapeutic effects for malaria. Therefore, ADA is of continuing interest for inhibitor design. Stable structural mimics of ADA transition states are powerful inhibitors. Here we report the transition-state structures of PfADA, HsADA, and bovine ADA (BtADA) solved …

Organisms Associated With Bacterial Vaginosis In Nigerian Women As Determined By Pcr-Dgge And 16s Rrna Gene Sequence, Kingsley Anukam, Gregor Reid

Kingsley C Anukam

Background: Bacterial vaginosis (BV) is a condition with diverse etiology. This condition predisposes women to increased susceptibility to sexually transmitted diseases, including human immunodeficiency virus (HIV) infections and preterm birth. The diagnostic methods currently adopted in the evaluation of patient samples for BV are arguably Amsel criteria, and Nugent score that require microscopy and expert interpretation. These two methods are still subjective. Objective: The objective of this study was to determine the organisms present in the vagina of 34 HIV negative Nigerian women diagnosed as having bacterial vaginosis by using molecular techniques. Methods: The vaginal samples were subjected to DNA …

Acyclic Ribooxacarbenium Ion Mimics As Transition State Analogues Of Human And Malarial Purine Nucleoside Phosphorylases, Erika Taylor, Keith Clinch, Peter Kelly, Lei Li, Gary Evans, Peter Tyler, Vern Schramm

Erika A. Taylor, Ph.D.

Transition state analogues of PNP, the Immucillins and DADMe-Immucillins, were designed to match transition state features of bovine and human PNPs, respectively. A third generation of inhibitors has been designed that contain an acyclic iminoalcohol to replace the cyclic mimic of the ribooxacarbenium ion at the transition states of PNPs. The best third generation inhibitor is equivalent to the best inhibitors found in the previous transition state analogues.

Synthesis Of 5‘-Methylthio Coformycins:  Specific Inhibitors For Malarial Adenosine Deaminase, Peter Tyler, Erika Taylor, Richard Froehlich, Vern Schramm

Erika A. Taylor, Ph.D.

Transition state theory suggests that enzymatic rate acceleration (kcat/knon) is related to the stabilization of the transition state for a given reaction. Chemically stable analogues of a transition state complex are predicted to convert catalytic energy into binding energy. Because transition state stabilization is a function of catalytic efficiency, differences in substrate specificity can be exploited in the design of tight-binding transition state analogue inhibitors. Coformycin and 2‘-deoxycoformycin are natural product transition state analogue inhibitors of adenosine deaminases (ADAs). These compounds mimic the tetrahedral geometry of the ADA transition state and bind with picomolar dissociation constants to enzymes from bovine, …

The Regulation Of Genes And Genomes By Small Rnas., Victor Ambros, Xuemei Chen

Victor R. Ambros

A recent Keystone Symposium on 'MicroRNAs and siRNAs: Biological Functions and Mechanisms' was organized by David Bartel and Shiv Grewal (and was held in conjunction with 'RNAi for Target Validation and as a Therapeutic', organized by Stephen Friend and John Maraganore). The 'MicroRNAs and siRNAs' meeting brought together scientists working on diverse biological aspects of small regulatory RNAs, including microRNAs, small interfering RNAs (siRNAs) and Piwi-interacting RNAs (piRNAs and rasiRNAs). Among the themes discussed were the diversity of small regulatory RNAs and their developmental functions, their biogenesis, the identification of their regulatory targets, their mechanisms of action, and their roles …

Electromyographic Comparison Of A Stability Ball Crunch With A Traditional Crunch, Eric Sternlicht, Stuart Rugg, Larissa Fujii, Keri Tomomitsu, Matt Seki

Stuart Rugg

The purpose of this study was to compare abdominal muscle activity while performing a crunch on a stability ball with a traditional crunch. Forty-one healthy adults (23 men and 18 women) participated in the study. The subjects performed the crunch with the ball in 2 positions, 1 with the ball at the level of the inferior angles of the scapula (SB-high) and 1 with the ball at the level of the lower lumbar region of the back (SB-low). Surface electromyography was recorded from the upper and lower portions of the rectus abdominis and the external oblique during each repetition. Electromyography …

Antioxidants Preserve Macrophage Phagocytosis Of Pseudomonas Aeruginosa During Hyperoxia, Ali Azghani

Ali Azghani

Reversible Birefringence Suggests A Role For Molecular Self-Assembly In Forisome Contractility, Winfried Peters, Reinhard Schnetter, Michael Knoblauch

Winfried S. Peters

Potent Effect Of Target Structure On Microrna Function, Peter Williams, Dang Long, Rosalind Lee, Chi Chan, Victor Ambros, Ye Ding

Victor R. Ambros

MicroRNAs (miRNAs) are small noncoding RNAs that repress protein synthesis by binding to target messenger RNAs. We investigated the effect of target secondary structure on the efficacy of repression by miRNAs. Using structures predicted by the Sfold program, we model the interaction between an miRNA and a target as a two-step hybridization reaction: nucleation at an accessible target site followed by hybrid elongation to disrupt local target secondary structure and form the complete miRNA-target duplex. This model accurately accounts for the sensitivity to repression by let-7 of various mutant forms of the Caenorhabditis elegans lin-41 3' untranslated region and for …

Neighboring Group Participation In The Transition State Of Human Purine Nucleoside Phosphorylase, Andrew Murkin, Matthew Birck, Agnes Rinaldo-Matthis, Wuxian Shi, Erika Taylor, Steven Almo, Vern Schramm

Erika A. Taylor, Ph.D.

No abstract provided.

Characterization Of Microrna Expression Levels And Their Biological Correlates In Human Cancer Cell Lines., Caifu Chen, Arti Gaur, David Jewell, Yu Liang, Dana Ridzon, Jason Moore, Victor Ambros, Mark Israel

Victor R. Ambros

MicroRNAs are small noncoding RNAs that function by regulating target gene expression posttranscriptionally. They play a critical role in developmental and physiologic processes and are implicated in the pathogenesis of several human diseases including cancer. We examined the expression profiles of 241 human microRNAs in normal tissues and the NCI-60 panel of human tumor-derived cell lines. To quantify microRNA expression, we employed a highly sensitive technique that uses stem-loop primers for reverse transcription followed by real-time PCR. Most microRNAs were expressed at lower levels in tumor-derived cell lines compared with the corresponding normal tissue. Agglomerative hierarchical clustering analysis of microRNA …

Med19(Rox3) Regulates Intermodule Interactions In The Saccharomyces Cerevisiae Mediator Complex., Shamara Baidoobonso, Benjamin Guidi, Lawrence Myers

Shamara M Baidoobonso, PhD

The Saccharomyces cerevisiae Mediator is a 25-subunit complex that facilitates both transcriptional activation and repression. Structural and functional studies have divided Mediator subunits into four distinct modules. The Head, Middle, and Tail modules form the core functional Mediator complex, whereas a fourth, the Cyc-C module, is variably associated with the core. By purifying Mediator from a strain lacking the Med19(Rox3) subunit, we have found that a complex missing only the Med19(Rox3) subunit can be isolated under mild conditions. Additionally, we have established that the entire Middle module is released when the Deltamed19(rox3) Mediator is purified under more stringent conditions. In …

The 2007 George W. Beadle Medal. Robert K. Herman., Victor Ambros

Victor R. Ambros

No abstract provided.

Volatile Compounds On The Leaf Surface Of Intact And Regrowth Tarbush (Flourensia Cernua Dc) Canopies, Ed Frederickson, R. Estell, M. Remmenga

Ed L. Frederickson

Shrub expansion into desert grasslands is a serious problem resulting in loss of forage and rangeland productivity. Flourensia cernua DC (tarbush) is one such shrub contributing to the decline of Chihuahuan Desert grasslands. Our previous research has shown tarbush consumption by sheep and goats to be negatively related to leaf surface concentration of individual terpenes and epicuticular wax. Concentrations of compounds such as terpenes often change with plant age and phenology. Our objective was to examine the effect of altering the vegetative state of tarbush on volatile chemicals. Ninety tarbush plants were randomly selected, and all biomass within 10 cm …

Taxonomy, Life History, And Population Sex Ratios Of North American Dasineura (Diptera: Cecidomyiidae) On Goldenrods (Asteraceae), Warren Abrahamson, N. Dorchin, C.E. Clarkin, E.R. Scott, M.P. Luongo

Warren G. Abrahamson, II

No abstract provided.

Holy Toyland, Stephen Asma

Stephen T Asma

No abstract provided.

Exercise-Mediated Regulation Of Hsp70 Gene Expression Following Exercise Training, C.W. Melling, David Thorp, Kevin Milne, Matthew Krause, Earl Noble

Jamie Melling

An issue central to understanding the biological benefits associated with regular exercise training is to elucidate the intracellular mechanisms governing exercise-conferred cardioprotection. Heat shock proteins (HSPs), most notably the inducible 70-kDa HSP family member Hsp70, are believed to participate in the protection of the myocardium during cardiovascular stress. Following acute exercise, activation of PKA mediates the suppression of an intermediary protein kinase, ERK1/2, which phosphorylates and suppresses the activation of the heat shock transcription factor 1 (HSF1). However, following exercise training, ERK1/2 has been reported to regulate the transcriptional activation of several genes involved in cell growth and proliferation and …

Hydroperiod And Metamorphosis In The Small-Mouthed Salamander

Travis J. Ryan