Cycling Through History: Making an American Sport 1880-present, Blog 1

Student blog posts from the Great VCU Bike Race Book

Learning fast: broadband and the future of education

Educational institutions have always had a central place in the online age. Before the advent of high-speed broadband, other communications technologies and services also played a big role in education.  University researchers were among the first Australian users of what became known as the Internet. When the domain name system was deployed in the mid-1980s, the .au domain was delegated to Robert Elz at the University of Melbourne. When the Australian Vice-Chancellor’s Committee decided to set up a national communications network to support research, Geoff Huston transferred to its payroll from ANU to work as technical manager for AARNet, whose current chief executive, Chris Hancock, is interviewed by Liz Fell in this issue. When a 56 kbps ARPANET link with Australia was made by NASA and the University of Hawaii via Intelsat in June 1989, the connection was established in Elz’s University of Melbourne laboratory. (Clarke 2004: 31) In earlier times, the postal service made learning-at-a-distance possible by ‘correspondence’, particularly in remote areas of Australia. Advances in radio communications made it easier and the interactivity more immediate. Television sets and later video cassette and DVD players and recorders made it more visual. The telephone provided a tool of communication for teachers and learners; the best of them understood that most people were both at different times. Then simple low bandwidth tools like email and web browsing provided new ways for students, teachers and their institutions to communicate and distribute and share information. Learning management systems like Blackboard have been widely deployed through the education sector. Information that was once housed in libraries is now available online and social media platforms are providing new ways for students to collaborate. Ubiquitous, faster broadband and mobile access via smartphones and tablets promise further transformations. &nbsp

Biosynthetic pathways in Oxalobacter formigenes

Oxalate is the only substrate that supports the growth of the gram negative anaerobe, Oxalobacter formigenes. Oxalate is decarboxylated to formate plus CO[subscript]2. A small amount of acetate (0.5-1 mM) is required for biosynthetic reactions. Oxalate is reduced and assimilated into cell biomass by aerobic oxalate-degrading bacteria using either the glycerate pathway or the serine pathway. Oxalate is reduced to 3P-glycerate and assimilated as a C[subscript]3 unit. We detected the enzymatic activities of glycerate pathway but not those of the serine pathway in cell-free extracts of O. formigenes;Four potential sources of carbon for cell biomass are available to O. formigenes, oxalate, acetate, formate and CO[subscript]2. We grew the organism in [superscript]14 C labeled carbon sources and determined the contribution of each of these sources to cell carbon. O. formigenes derived at least 54% of its cell carbon from oxalate and at least 7% from acetate. The only other carbon source utilized was CO[subscript]3. Formate was not incorporated to a significant extent. Carbon from [superscript]14 C-oxalate and [superscript]14 CO[subscript]3 was detected in amino acids derived from [alpha]-ketoglutarate, oxaloacetate, pyruvate, 3P-glycerate and in the aromatic amino acids. Amino acids derived from [alpha]-ketoglutarate, oxaloacetate and pyruvate contained carbon derived from [superscript]14 C-acetate;When O. formigenes was grown on [superscript]13 C-labeled oxalate, acetate or CO[subscript]3,the labeling patterns of the amino acids were consistent with their formation through common biosynthetic pathways. [superscript]13 C from oxalate was detected in the majority of the carbons from all of the amino acids. Approximately 60% of the acetate was incorporated as a C[subscript]2 unit into four amino acids (glutamate, proline, arginine and leucine). The other 40% of the acetate was split and was detected in amino acids derived from oxaloacetate and pyruvate;Enzymatic activities detected in cell-free extracts included: glutamate dehydrogenase, phosphoenolpyruvate carboxylase, pyruvate carboxylase, citrate synthase and isocitrate dehydrogenase. These findings support the [superscript]14 C and [superscript]13 C data which indicate that O. formigenes assimilates acetate into protein using the first third of the TCA pathway and that C[subscript]4 units are formed from C[subscript]3 units by carboxylation of pyruvate or PEP

Assimilation of Oxalate, Acetate, and CO2 by Oxalobacter formigenes

Oxalobacterformigenes is the only well-documented oxalate-degrading bacterium isolated from the gastrointestinal tract of animals. The production of ATP by Oxalobacter formigenes is centered around oxalate metabolism and oxalate is required for growth. A small amount of acetate (0.5 mM) is also required. Oxalate is decarboxylated to formate plus CO2 in nearly equimolar amounts. Experiments were conducted to determine which potential carbon sources (oxalate, acetate, formate, CO2) were assimilated by Oxalobacter formigenes and which metabolic pathways were operative in carbon assimilation. Measurements of the specific activities of total cell carbon after growth with different 14C-labeled precursors indicated that at least 54% of the total cell carbon was derived from oxalate and at least 7% was derived from acetate. Carbonate was also assimilated, but formate was not a significant source of cell carbon. Labeling patterns in amino acids from cells grown in [14C]oxalate or 14CO3 were different; however, in both cases 14C was widely distributed into most cellular amino acids. Carbon from [14C]acetate was less widely distributed and detected mainly in those amino acids known to be derived from α-ketoglutarate, oxaloacetate, and pyruvate. Cell-free extracts contained citrate synthase, isocitrate dehydrogenase, and malate dehydrogenase activities. The labeling observed in amino acids derived from acetate is in agreement with the function of these enzymes in biosynthesis and indicates that the majority of acetate carbon entered into amino acid biosynthesis via well-known pathways

Anabolic Incorporation of Oxalate by Oxalobacter formigenes

Cell-free lysates of the strict anaerobe Oxalobacter formigenes contained the following enzymatic activities: oxalyl coenzyme A reductase, glyoxylate carboligase, tartronic semialdehyde reductase, and glycerate kinase. NAD(P)-linked formate dehydrogenase, serine-glyoxylate aminotransferase, and NAD(P) transhydrogenase activities were not detected. These results support the hypothesis that O. formigenes assimilates carbon from oxalate by using the glycerate pathway, whereby oxalate is reduced to 3-phosphoglycerate before entering common biosynthetic pathways

Une institution française : La nouvelle revue française de Jean Paulhan

Aujourd’hui La NRF est reconnue pour avoir constitué l’un des plus grands phénomènes culturels de la France moderne. Au sortir de la guerre de 1914-1918, la revue fondée en 1908-1909 par André Gide et ses amis est déjà en voie d’institutionnalisation. Dans cette contribution, on va tenter une analyse du rôle de Jean Paulhan dans le remarquable succès de cette revue entre 1925 et 1940. D’abord, on voit par quels chemins Paulhan arrive à la revue pour y apporter l’influence d’une nouvelle génération d’écrivains d’avant-garde. Ensuite, on va explorer comment Paulhan travaille à la consolidation du succès de la revue, et dans un dernier temps, on va découvrir comment le directeur de La NRF affronte les défis idéologiques des années précédant à l’éclatement de la guerre en 1939.Today LaNRF is recognised as one of France’s greatest cultural phenomena. Immediately after the First World War, the review founded in 1908-1909 by André Gide and his friends was already well on the way to becoming an institution. In this article we shall attempt an analysis of Jean Paulhan’s role in consolidating the remarkable success of the review between 1925 and 1940. First we examine how Paulhan arrived at the review, bringing with him the influence of a new generation of avant-garde writers. Thereafter we explore how Paulhan consolidated the success of LaNRF, and finally we shall suggest how he steered the review through the dangerous ideological waters of the 1930s towards the outbreak of war in 1939

Genome-Wide Transposon Mutagenesis Reveals a Role for pO157 Genes in Biofilm Development in Escherichia coli O157:H7 EDL933

Enterohemorrhagic Escherichia coli O157:H7, a world-wide human food-borne pathogen, causes mild to severe diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. The ability of this pathogen to persist in the environment contributes to its dissemination to a wide range of foods and food processing surfaces. Biofilms are thought to be involved in persistence, but the process of biofilm formation is complex and poorly understood in E. coli O157:H7. To better understand the genetics of this process, a mini-Tn5 transposon insertion library was constructed in strain EDL933 and screened for biofilm-negative mutants using a microtiter plate assay. Ninety-five of 11,000 independent insertions (0.86%) were biofilm negative, and transposon insertions were located in 51 distinct genes/intergenic regions that must be involved either directly or indirectly in biofilm formation. All of the 51 biofilm-negative mutants showed reduced biofilm formation on both hydrophilic and hydrophobic surfaces. Thirty-six genes were unique to this study, including genes on the virulence plasmid pO157. The type V secreted autotransporter serine protease EspP and the enterohemolysin translocator EhxD were found to be directly involved in biofilm formation. In addition, EhxD and EspP were also important for adherence to T84 intestinal epithelial cells, suggesting a role for these genes in tissue interactions in vivo