Life Sciences Commons^™

The Role Of Protein Glycosylation In The Virulence Of The Gastric Pathogens Helicobacter Pylori And Campylobacter Jejuni, Alexandra Merkx-Jacques, C. Creuzenet

Alexandra Merkx-Jacques

H. pylori and C. jejuni are Gram-negative gastro-intestinal pathogens whose virulence is highly affected by protein glycosylation. The former causes gastric ulcers and cancer, while the latter causes enteritis and neurological disorders. Due to emerging drug-resistant strains, new treatments are needed.

In both bacteria, the flagellins are essential virulence factors glycosylated by pseudaminic acid (PA). We have identified and disrupted genes required for PA synthesis in both bacteria, and shown that this affects flagellin production. Further analysis and glycoprotein staining revealed that in H. pylori, the PA pathway is necessary for the glycosylation of proteins other than flagellins and …

Chess, Chance And Conspiracy, Mark Segal

Mark R Segal

Chess and chance are seemingly strange bedfellows. Luck and/or randomness have no apparent role in move selection when the game is played at the highest levels. However, when competition is at the ultimate level, that of the World Chess Championship (WCC), chess and conspiracy are not strange bedfellows, there being a long and colorful history of accusations levied between participants. One such accusation, frequently repeated, was that all the games in the 1985 WCC (Karpov vs Kasparov) were fixed and prearranged move by move. That this claim was advanced by a former World Champion, Bobby Fischer, argues that it ought …

Water Uptake By Older Roots: Evidence From Desert Succulents, Gretchen North, E. Baker

Gretchen North

Desert succulents are renowned for their rapid recovery of shoot function after periods of drought as a result of shoot succulence, root–shoot interactions, and key root properties. Near the base of the shoot, the proximal (generally older) roots appear to play a major role in the rapid uptake and delivery of water, especially after a period of soil drying when the rest of the root system has a lower hydraulic conductance. In all of the cacti, agaves, and yuccas examined to date, hydraulic conductance for the proximal root zone is unexpectedly high. Substantial water uptake by older roots of cacti …

The Extracellular Chaperone Clusterin Influences Amyloid Formation And Toxicity By Interacting With Pre-Fibrillar Structures, Justin Yerbury, Stephen Poon, Sarah Meehan, Brianna Thompson, Janet Kumita, Christopher Dobson, Mark Wilson

Mark R Wilson

Clusterin is an extracellular chaperone present in all disease-associated extracellular amyloid deposits, however, its roles in amyloid formation and protein deposition in vivo are poorly understood. The current study initially aimed to characterise the effects of clusterin on amyloid formation in vitro by a panel of eight protein substrates. Two of the substrates (Alzheimer's beta peptide and a PI3-SH3 domain) were then used in further experiments to examine the effects of clusterin on amyloid cytotoxicity and to probe the mechanism of clusterin action. We show that clusterin exerts potent effects on amyloid formation, the nature and extent of which vary …

The Extracellular Chaperone Clusterin Potently Inhibits Human Lysozyme Amyloid Formation By Interacting With Prefibrillar Species, Mark Wilson, Justin Yerbury, Stephen Poon, Christopher Dobson, C V Robinson, Elise Stewart, Janet Kumita, Mireille Dumoulin, Gemma Caddy, Christine Hagan

Mark R Wilson

We have studied the effects of the extracellular molecular chaperone, clusterin, on the in vitro aggregation of mutational variants of human lysozyme, including one associated with familial amyloid disease. The aggregation of the amyloidogenic variant I56T is inhibited significantly at clusterin-to-lysozyme ratios as low as 1:80 (i.e. one clusterin molecule per 80 lysozyme molecules). Experiments indicate that under the conditions where inhibition of aggregation occurs, clusterin does not bind detectably to the native or fibrillar states, or to the monomeric transient intermediate known to be a key species in the aggregation reaction. Rather, it seems to interact with oligomeric species …

Genetics And Biochemistry Of Protein Glycosylation In Campylobacter Jejuni, Alexandra Merkx-Jacques, S. Vijayakumar, M. Demendi, D. Ratnayake, C. Dozois, C. Creuzenet

Alexandra Merkx-Jacques

BACKGROUND: C. jejuni produces numerous glycoproteins, including flagellins, which are important for virulence. The flagellins harbour pseudaminic acid (PA) whereas other glycoproteins harbour diacetamidobacillosamine (DAB). We are investigating the genetics and biochemistry of protein glycosylation in C. jejuni to identify the enzymes involved, and determine their activity and roles in virulence. We focused on two homologous pathways comprising each a putative dehydratase, aminotransferase and acetyltransferase, namely {Cj1293, Cj1294 and Cj1298} and {Cj1120c, Cj1121c and Cj1123c}.

METHODS: All enzymes were overexpressed and purified before monitoring their activity by capillary electrophoresis. The cj1121c and cj1294 genes were disrupted by a chloramphenicol resistance …

Runx2 Is Essential For Larval Hyobranchial Cartilage Formation In Xenopus Laevis, Ryan Kerney, Joshua Gross, James Hanken

Ryan Kerney

The vertebrate transcription factor protein Runx2 is regarded as a “master regulator” of bone formation due to the dramatic loss of the osseous skeleton in the mouse homozygous knockout. However, Runx2 mRNA also is expressed in the pre-hypertrophic cartilaginous skeleton of the mouse and chicken, where its developmental function is largely unknown. Several tiers of Runx2 regulation exist in the mouse, any of which may account for its seeming biological inactivity during early stages of skeletogenesis. Unlike mouse and chicken, zebrafish require Runx2 function in early cartilage differentiation. The present study reveals that the earlier functional role of Runx2 in …

Effects Of Glycosylation On The Structure And Function Of The Extracellular Chaperone Clusterin, Elise Stewart, Andrew Aquilina, Simon B Easterbrook-Smith, D Murphy-Durland, C Jacobsen, S Moestrup, Mark Wilson

Mark R Wilson

Clusterin is the first well characterized, constitutively secreted extracellular chaperone that binds to exposed regions of hydrophobicity on non-native proteins. It may help control the folding state of extracellular proteins by targeting them for receptor-mediated endocytosis and intracellular lysosomal degradation. A notable feature of secreted clusterin is its heavy glycosylation. Although carbohydrate comprises approximately 20−25% of the total mass of the mature molecule, its function is unknown. Results from the current study demonstrate that deglycosylation of human serum clusterin had little effect on its overall secondary structure content but produced a small increase in solvent-exposed hydrophobicity and enhanced the propensity …

Identifying The Core Periodical Literature Of The Agricultural Communications Documentation Center, Joseph Zumalt

Joseph R. Zumalt

Agricultural communications" is an emerging field which is naturally both part of the "agriculture" and "communications" literature. However, it is much broader than just a subset of each. The coverage of standard databases such as CAB Abstracts and Communication Abstracts, while a good start, does not sufficiently cover the field. The Agricultural Communications Documentation Center (ACDC) at the University of Illinois at Urbana-Champaign has, over the last quarter century, worked to help define and collect this literature, by identifying relevant documents and entering them into a Web-searchable Microsoft Access database. An analysis of this database reveals important clues concerning the …

Radial Density Distribution And Symmetry Of A Potexvirus, Narcissus Mosaic Virus, Amy Kendall, Wen Bian, Justin Junn, Ian Mccullough, David Gore, Gerald Stubbs

Ian McCullough

Narcissus mosaic virus is a Potexvirus, a member of the Flexiviridae family of filamentous plant viruses. Fiber diffraction patterns from oriented sols of narcissus mosaic virus have been used to determine the symmetry and structural parameters of the viral helix. The virions have a radius of 55 ± 5 Å. The viral helix has a pitch of 34.45 ± 0.5 Å, with 7.8 subunits per turn of the helix. We conclude that all members of the Potexvirus genus have close to 8 subunits per helical turn.

La Cueva De Los Pocitos (El Hierro): Descricpion Y Biocenosis, S. De La Cruz, Ana Reboleira, Eduardo Muñoz, Nieves Zurita, Pedro Oromí

Ana Sofia P.S. Reboleira

The survey and a geomorphological description of Cueva de los Pocitos lava tube is presented. The results of measuring the environmental parameters are provided, as well as those of a faunistic study carried out in the spring and fall of 2000. A total of 552 of arthropods were collected, belonging to at least 30 different species, 8 of them being troglobites. A comparison with the faunistic richness of the other caves of El Hierro is also made.

Legacy Of Land Use In Southern Appalachian Forests: Effects On Terrestrial Salamander Abundance Along Edges And Within Abandoned Logging Roads, R. Semlitsch,, Travis Ryan, M. Chatfield, B. Drehman, K. Hamed, N. Pekarek, M. Spath

Travis J. Ryan

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

Helen O'Neill

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 …

Effects Of Resource Availability On Tolerance Of Herbivory: A Review And Assessment Of Three Opposing Models, Warren Abrahamson, M.J. Wise

Warren G. Abrahamson, II

No abstract provided.

Use Of Gene Profiling To Describe A Niche For Dendritic Cell Development, Geneviève Despars, Terence O'Neill, Helen O'Neill

Helen O'Neill

Gene profiling provides a multitude of data on individual gene expression. The view is expressed here that unreplicated data can be used in a descriptive way to compare cell populations in terms of their lineage characteristics and function. In these studies, the aim is to provide a snapshot of gene expression or its absence as a reflection of cell lineage or type, rather than gain a reliable expression measure for all genes expressed. The data set used in this analysis represents gene expression in the splenic stroma STX3 supportive of dendritic cell hematopoiesis and the lymph node stroma 2RL22, which …

Fisheries Independent Assessment Of A Returning Fishery: Abundance Of Juvenile White Seabass (Atractoscion Nobilis) In The Shallow Nearshore Waters Of The Southern California Bight, 1995–2005, Larry G. Allen, Daniel J. Pondella Ii, Michael A. Shane

Daniel Pondella

Nearshore, coastal and embayment areas off southern California were sampled to determine the spatial and temporal patterns abundance and size distributions of young white seabass in the shallow (5–14 m) waters from Santa Barbara south to Imperial Beach off San Diego. A total of 19 stations, 13 in nearshore coastal waters and 6 in embayments, dispersed along the Southern California Bight were surveyed in each sampling month using 45.7 m variable mesh, monofilament gill nets. In the 11-year period of sampling (April 1995–June 2005), a total of 8075 juvenile white seabass was captured in 42 sampling months. The mean catch-per-unit-effort …