Structural modification of polysaccharides: A biochemical-genetic approach

Polysaccharides have a wide range of industrial and biomedical applications. An industry trend is underway towards the increased use of bacteria to produce polysaccharides. Long term goals of this work are the adaptation and enhancement of saccharide properties for electronic and optic applications. In this report we illustrate the application of enzyme-bearing bacteriophage on strains of the enteric bacterium Klebsiella pneumoniae, which produces a polysaccharide with the relatively rare rheological property of drag-reduction. This has resulted in the production of new polysaccharides with enhanced rheological properties. Our laboratory is developing techniques for processing and structurally modifying bacterial polysaccharides and oligosaccharides which comprise their basic polymeric repeat units. Our research has focused on bacteriophage which produce specific polysaccharide degrading enzymes. This has lead to the development of enzymes generated by bacteriophage as tools for polysaccharide modification and purification. These enzymes were used to efficiently convert the native material to uniform-sized high molecular weight polymers, or alternatively into high-purity oligosaccharides. Enzyme-bearing bacteriophage also serve as genetic selection tools for bacteria that produce new families of polysaccharides with modified structures

Identity, Rationality, and Emotion in the Processes of State Disintegration and Reconstruction

I wish to address both a substantive and a methodological issue in this chapter. Substantively, I will discuss the process of state disintegration and reconstruction. Here, I will draw on the experience of Eastern Europe following the collapse of Communism. Today, more than twenty new states occupy the territories formerly held by the Soviet Union, Yugoslavia, and Czechoslovakia. Furthermore, the process of breakdown and rebuilding is incomplete, especially in terms of identity issues. For example, while most people have some understanding of how the first Yugoslavia collapsed, few appreciate how the second “rump” Yugoslavia and the surrounding territories remain in flux. Albanians and Slavs are working toward new political and social equilibria in Macedonia, Montenegro, Kosovo, and the three mixed municipalities in Serbia proper (Presevo, Bujanovac, and Medvedje). In Montenegro, the Slavic population is divided over whether they are Montenegrins, Serbs, or simultaneously Montenegrins and Serbs. In the Sandzak, people are debating whether they are Bosnjaks or just Muslims. In Moldova, a Dniestrian Republic rules a sliver of land on the left bank of Dniester River while the Gagauz have been given ethno-territorial autonomy within the entity on the right bank. In the Baltic republics, citizenship laws continue to be a matter of controversy

Update and Revision of the School Board Policies Manual of the Blair Community School System

Although boards of education have been in existence for 300 years in the United States, until the 1950\u27s little attention had been paid to the provisions of well organized and systematically written board policies. It has been only since the 1950\u27s that educational policy development has been commonly accepted as the most important function of local school boards. The decade of the 1960\u27s was a period of rapid change for public education. School boards were challenged and subjected to sharp criticisms. Employee professional negotiations, militant students, community factions, and troubled taxpayers brought to bear new pressures to boards of education. The already difficult task of offering quality education for all children by school boards became even more awesome than ever before

Varieties of Insurgency and Counterinsurgency in Iraq, 2003–2009

Varieties of Insurgency and Counterinsurgency in Iraq, 2003-2009 offers a useful analytical framework for understanding how and why rebellions either grow or diminish. This case study was created to focus on two specific challenges that operators and practitioners faced in Iraq: how to understand the actors and the complex irregular warfare environment; and how to manage interaction, adaptation, and reassessment in irregular warfare.https://digital-commons.usnwc.edu/ciwag-case-studies/1004/thumbnail.jp

Structurally altered capsular polysaccharides produced by mutant bacteria

Structurally altered capsular polysaccharides are produced by mutant bacteria. These polysaccharides are isolated by selecting a wild type bacterial strain and a phage producing degradative enzymes that have substrate specificity for the capsular polysaccharides produced by the wild type bacteria. Phage-resistant mutants producing capsular polysaccharides are selected and the structurally altered capsular polysaccharide is isolated therefrom

Method for producing capsular polysaccharides

Structurally altered capsular polysaccharides are produced by mutant bacteria. These polysaccharides are isolated by selecting a wild type bacterial strain and a phage producing degradative enzymes that have substrate specificity for the capsular polysaccharides produced by the wild type bacteria. Phage-resistant mutants producing capsular polysaccharides are selected and the structurally altered capsular polysaccharide is isolated therefrom

Developmental Regulation of an Adhesin Gene during Cellular Morphogenesis in the Fungal Pathogen Candida albicans

Peer reviewedPublisher PD

Evidence for Replicative Repair of DNA Double-Strand Breaks Leading to Oncogenic Translocation and Gene Amplification

Nonreciprocal translocations and gene amplifications are commonly found in human tumors. Although little is known about the mechanisms leading to such aberrations, tissue culture models predict that they can arise from DNA breakage, followed by cycles of chromatid fusion, asymmetric mitotic breakage, and replication. Mice deficient in both a nonhomologous end joining (NHEJ) DNA repair protein and the p53 tumor suppressor develop lymphomas at an early age harboring amplification of an IgH/c-myc fusion. Here we report that these chromosomal rearrangements are initiated by a recombination activating gene (RAG)-induced DNA cleavage. Subsequent DNA repair events juxtaposing IgH and c-myc are mediated by a break-induced replication pathway. Cycles of breakage-fusion-bridge result in amplification of IgH/c-myc while chromosome stabilization occurs through telomere capture. Thus, mice deficient in NHEJ provide excellent models to study the etiology of unbalanced translocations and amplification events during tumorigenesis

Correlation between arterial blood volume obtained by arterial spin labelling and cerebral blood volume in intracranial tumours.

OBJECTIVE: To compare measurements of the arterial blood volume (aBV), a perfusion parameter calculated from arterial spin labelling (ASL), and cerebral blood volume (CBV), calculated from dynamic susceptibility contrast (DSC) MRI. In the clinic, CBV is used for grading of intracranial tumours. MATERIALS AND METHODS: Estimates of aBV from the model-free ASL technique quantitative STAR labelling of arterial regions (QUASAR) experiment and of DSC-CBV were obtained at 3T in ten patients with eleven tumours (three grade III gliomas, four glioblastomas and four meningiomas, two in one patient). Parametric values of aBV and CBV were determined in the tumour as well as in normal grey matter (GM), and tumour-to-GM aBV and CBV ratios were calculated. RESULTS: In a 4-pixel ROI representing maximal tumour values, the coefficient of determination R (2) was 0.61 for the comparison of ASL-based aBV tumour-to-GM ratios and DSC-MRI-based CBV tumour-to-GM ratios and 0.29 for the comparison of parametric values of ASL-aBV and DSC-CBV, under the assumption of proportionality. Both aBV and CBV showed a non-significant tendency to increase when going from grade III gliomas to glioblastomas to meningiomas. CONCLUSION: These results suggest that measurement of aBV is a potential tool for non-invasive assessment of blood volume in intracranial tumours