10,681 research outputs found
Caulobacter crescentus adapts to phosphate starvation by synthesizing anionic glycoglycerolipids and a novel glycosphingolipid
No full textCaulobacter crescentus adapts to phosphate starvation by elongating its cell body and a polar stalk structure. The stalk is an extension of the Gram-negative envelope containing inner and outer membranes as well as a peptidoglycan cell wall. Cellular elongation requires a 6- to 7-fold increase in membrane synthesis, yet phosphate limitation would preclude the incorporation of additional phospholipids. In the place of phospholipids, C. crescentus can synthesize several glycolipid species, including a novel glycosphingolipid (GSL-2). While glycosphingolipids are ubiquitous in eukaryotes, the presence of GSL-2 in C. crescentus is surprising since GSLs had previously been found only in Sphingomonas species, in which they play a role in outer membrane integrity. In this paper, we identify three proteins required for GSL-2 synthesis: CcbF catalyzes the first step in ceramide synthesis, while Sgt1 and Sgt2 sequentially glycosylate ceramides to produce GSL-2. Unlike in Sphingomonas, GSLs are nonessential in C. crescentus; however, the presence of ceramides does contribute to phage resistance and susceptibility to the cationic antimicrobial peptide polymyxin B. The identification of a novel lipid species specifically produced upon phosphate starvation suggests that bacteria may be able to synthesize a wider variety of lipids in response to stresses than previously observed. Uncovering these lipids and their functional relevance will provide greater insight into microbial physiology and environmental adaptation.Peer reviewe
Rex, sit: digital modeling of Tyrannosaurus rex at rest
No full textKent A. Stevens, Peter Larson, Eric D. Wills, Art Anderson (2008): Rex, sit: digital modeling of Tyrannosaurus rex at rest. In: Peter Larson, Kenneth Carpenter (Eds): Tyrannosaurus rex, the tyrant king. lndiana University Press: 192-203, DOI: http://doi.org/10.5281/zenodo.394285
tritrophic-dispersal-model: Code used for creating figures for "Non-hierarchical dispersal promotes stability and resilience in a tri-trophic metacommunity"
No full text<p>This is the commented code used for creating figures for the paper. Any questions regarding the code should be directed to the corresponding author and repository owner (Eric Pedersen). </p>
Q & A - Eric Davidson
No full textEric Davidson graduated from the University of Pennsylvania in 1954 and received his PhD from Rockefeller University in 1963. He remained at Rockefeller until 1971 when he moved to Caltech in Pasadena, California. He was elected to the U.S. National Academy of Sciences in 1985, and is at present Norman Chandler Professor of Cell Biology in the Division of Biology, Caltech. He is the author of 5 books and over 400 papers on developmental gene regulation and evolution of genomic programs for development. For the last decade his work has focused on theory and operation of developmental gene regulatory networks
Perspective: Adhesion Mediated Signal Transduction in Bacterial Pathogens
No full textDuring the infection process, pathogenic bacteria undergo large-scale transcriptional changes to promote virulence and increase intrahost survival. While much of this reprogramming occurs in response to changes in chemical environment, such as nutrient availability and pH, there is increasing evidence that adhesion to host-tissue can also trigger signal transduction pathways resulting in differential gene expression. Determining the molecular mechanisms of adhesion-mediated signaling requires disentangling the contributions of chemical and mechanical stimuli. Here we highlight recent work demonstrating that surface attachment drives a transcriptional response in bacterial pathogens, including uropathogenic Escherichia coli (E. coli), and discuss the complexity of experimental design when dissecting the specific role of adhesion-mediated signaling during infection.Peer reviewe
Eric C. Lincoln, Professor of Sociology and Religion, 1971
No full textThis is an interview with Eric C. Lincoln. Eric was a Professor of Sociology and religion, Union Theological Seminary and author of many books and articles on Negro history. In this recording the contributors discuss local memphis politics, sociology, and race relations compared to that of other cities in the South and the rest of the country
American public support for US military operations from Mogadishu to Baghdad technical appendixes
No full text"Contains the technical appendixes for a study that describes American public opinion toward the use of military force in support of the global war on terrorism ... The main document is Eric V. Larson and Bogdan Savych, American public support for U.S. military operations from Mogadishu to Baghdad, Santa Monica, CA: RAND Corporation, MG-231-A, 2004 [i.e. 2005]"--P. iii
10th C. Eric Lincoln Lecture Series, 1992
No full textPart of the 10th anniversary of the C. Eric Lincoln lecture series Dr. Love Henry Whelchel moderates a panel of scholars. The panel includes Dr. C. Eric Lincoln, Dr. Jacquelyn Grant, and Dr. John Hope Franklin. The panel discusses the life of George Washington Williams (author of History of the Negro Race in America). The discussion includes issues related to Womanist theology, Islamic religion, sociology, religion and history.The Atlanta University Center Robert W. Woodruff Library acknowledges the generous support of the National Endowment for Humanities - Humanities Collections and Reference Resources Implementation Project Grant in supporting the processing and digitization of a number of its major archival collections as part of the project: Spreading the Word: Expanding Access to African American Religious Archival Collections at the Atlanta University Center Robert W. Woodruff Library
Influence of CO2 on fishes in flowing water environments: implications for a non-physical barrier to movement
No full textSilver carp (Hypophthalmichthys molitrix) and bighead carp (H. nobilis) are invasive species that have become established in the upper reaches of the Illinois River, and are nearing the connection into Lake Michigan. To prevent the spread of these carp, as well as other fish, carbon dioxide (CO2) is being investigated as a potential nonphysical barrier. However, to date, most research on the effects of CO2 on fish behavior has occurred in static water conditions. Additionally, little is known about how elevated CO2 may affect swimming performance. Here, we investigate the effects that varying levels of dissolved CO2 will have on fish behavior and swimming performance in flowing water. Chapter 1 aims to identify threshold levels of CO2 required to elicit significant behavioral responses from the native surrogate species used (bluegill, Lepomis macrochirus, and largemouth bass, Micropterus salmoides). When exposed to a range of CO2 partial pressure (pCO2; < 400 μatm [ambient], 25,000 μatm, 50,000 μatm and 100,000μatm), bluegill showed a significant increase in activity at 25,000 μatm, whereas largemouth bass activity significantly increased at 100,000 μatm. Fish were also exposed to 50,000 μatm pCO2 in five successive bursts to investigate the effects of repeated exposure to CO¬2 on fish behavior. Both species displayed a significant increase in activity during the first exposure, but then successive exposures did not change activity levels relative to baseline (at ambient pCO2). Chapter 2 aims to quantify the effects of elevated CO2 on sustained (aerobic) and burst (anaerobic) swimming performance in largemouth bass. We found that sustained swimming performance significantly decreased at 100,000 μatm pCO2 and that burst swimming was unaffected by CO2. Additionally, ~15% of fish lost equilibrium during both sustained and burst swimming tests at 50,000 μatm, and nearly 70% of fish lost equilibrium during both sustained and burst swimming tests at 100,000 μatm, showing that the rate of loss of equilibrium significantly increased as pCO2 increased. These novel findings fill a knowledge gap regarding fish behavior and performance during exposure to elevated CO2 in flowing water, and also inform the development and deployment strategies of the proposed CO2 fish barriers.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-08-01The student, Eric Schneider, accepted the attached license on 2017-06-22 at 10:28.The student, Eric Schneider, submitted this Thesis for approval on 2017-06-22 at 10:33.This Thesis was approved for publication on 2017-07-03 at 15:16.DSpace SAF Submission Ingestion Package generated from Vireo submission #11247 on 2017-09-29 at 10:45:59Made available in DSpace on 2017-09-29T17:45:25Z (GMT). No. of bitstreams: 2
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Previous issue date: 2017-07-03Embargo set by: Colleen Fallaw for item 103468
Lift date: 2019-09-29T17:48:06Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 103468
Lift date: 2020-03-02T19:56:41Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 103468
Lift date: 2020-03-02T19:59:52Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 103468
Lift date: 2020-03-02T20:02:46Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 103468 on 2020-03-03T10:15:35Z
Differential modes of crosslinking establish spatially distinct regions of peptidoglycan in Caulobacter crescentus
No full textThe diversity of cell shapes across the bacterial kingdom reflects evolutionary pressures that have produced physiologically important morphologies. While efforts have been made to understand the regulation of some prototypical cell morphologies such as that of rod-shaped Escherichia coli, little is known about most cell shapes. For Caulobacter crescentus, polar stalk synthesis is tied to its dimorphic life cycle, and stalk elongation is regulated by phosphate availability. Based on the previous observation that C. crescentus stalks are lysozyme-resistant, we compared the composition of the peptidoglycan cell wall of stalks and cell bodies and identified key differences in peptidoglycan crosslinking. Cell-body peptidoglycan contained primarily DD-crosslinks between meso-diaminopimelic acid and D-alanine residues, whereas stalk peptidoglycan had more LD-transpeptidation (meso-diaminopimelic acid-meso-diaminopimelic acid), mediated by LdtD. We determined that ldtD is dispensable for stalk elongation; rather, stalk LD-transpeptidation reflects an aging process associated with low peptidoglycan turnover in the stalk. We also found that lysozyme resistance is a structural consequence of LD-crosslinking. Despite no obvious selection pressure for LD-crosslinking or lysozyme resistance in C. crescentus, the correlation between these two properties was maintained in other organisms, suggesting that DAP-DAP crosslinking may be a general mechanism for regulating bacterial sensitivity to lysozyme.Peer reviewe
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