Antibody Response of Monkeys to Invasion Plasmid Antigen D after Infection with Shigella spp.

The antigen preparation most often used for determining the levels of antibodies to virulence-associated proteins of Shigella spp. consists of a mixture of proteins (including IpaB, IpaC, IpaD, and VirG*) extracted from virulent shigellae with water (water extract). To overcome the lack of specificity for individual antigens in the water-extract enzyme-linked immunosorbent assay (ELISA), the ipaD gene from S. flexneri has been cloned, expressed to a high level, and purified for use in a new ELISA for the determination of the levels of antibody against IpaD in monkeys and humans challenged with shigellae. The IpaD ELISA for serum immunoglobulins G and A correlated well with the water-extract ELISA in that monkeys infected with S. flexneri or S. sonnei responded with high serum antibody titers in both assays. The IpaD assay required less antigen per well, had much lower background levels, and did not require correction with antigens from an avirulent organism. In conjunction with the water-extract ELISA, it was possible to identify infected animals that did not respond to IpaD but did produce antibodies that reacted in the water-extract ELISA. This indicates that even though IpaB, IpaC, and IpaD are essential for the invasiveness phenotype, the infected host does not always produce antibodies against all components of the invasiveness apparatus

Supplementary Reading Materials For Primary Grades Based On Children\u27s Reading Interests and On Natural and Factual Data Pertaining To Kansas

Childhood education has made rapid advancement during the past quarter of a century. It is no longer considered by leading educators as something to be imposed from without, but is rather thought of as the gradual unfolding of life from within. This modern concept includes both the child and the subject matter to be taught. From the child\u27s point of view such factors as innate ability, social traits, also the physical development as well as mental development, as well as mental development, serve as guides in setting up goals of achievement for the primary school grades. In the selection and organization of subject matters such factors as child nature, child interest and child experience as well as child growth enter into the picture. Several studies in research have been made which deal with some of these problems since they are of vital concern to the child and affect his school progress. Of primary importance in the beginning of education is the problem of selecting supplementary reading material for use in teaching reading in the primary grades, especially material which has local color and in which children have real interest. The specific problem of this thesis is the selection, organization, and compilation of material having a more or less direct association with the state of Kansas, and the use of this material in primary reading. The basic facts are to be drawn from pioneer and Indian life, folklore, nature study and myth as well as from the physical and geographic features of the State. The method or technique will no doubt reflect for the most part historic procedure, since these data are drawn from sources having direct association with the growth and development of the state. The organization of the thesis divides itself naturally into two major parts: first, the analytic; second, the synthetic. The analytic part pertains to a careful analysis of recent research studies made in children\u27s reading interests, the content of certain primary readers now in use in schools and also through the use of personal opinion solicited from teachers and pupils. The synthetic part involves the use of local data compiled in written story. These stories are to be written for pupils at primary level through the use of vocabulary studies which have been found through a study of children of ages normally found in primary grades

Supporting students' construction of hypermedia

This thesis considers the proposition that hypermedia may be employed effectively in higher education. More specifically, the question of its use by undergraduate music students to assist in writing essays and dissertations is investigated. The work begins with a review of general issues relating to educational hypermedia, such as its history, application, design and architecture. A user-centred approach to hypermedia development is advocated, and after critique and analysis of the literature, a framework for human-computer interaction for educational hypermedia is proposed. A case study is reported which serves to facilitate the undertaking of original research, as well as to evaluate the proposed framework. Other environments are also selected to carry out more generic research. Both reading strategies and writing strategies are investigated, and the results from these studies are used to conduct a repertory grid analysis of students' approaches to and perceptions of essay and dissertation development. The outcome of this experiment concludes with a proposal for a structural model of essay and dissertation development. Analysis of the model suggests the need for further survey analysis of taskartefact usage in specific educational domains, and experimental studies into electronic document manipulation and the reading of music from computer screens are investigated with respect to the case study environment. The implications of the research carried out in this thesis have assisted in and helped to justify the design of the prototype system HECTOR (Hypermedia, from Essay Conception TO Realisation). It aims to support students in their research, planning and writing of essays and dissertations. HECTOR has been evaluated in the field, and the results of this go some way to supporting the hypothesis of the thesis - that hypermedia can be employed effectively in higher education

The Shigella Type III Secretion System: An Overview from Top to Bottom

Shigella comprises four species of human-restricted pathogens causing bacillary dysentery. While Shigella possesses multiple genetic loci contributing to virulence, a type III secretion system (T3SS) is its primary virulence factor. The Shigella T3SS nanomachine consists of four major assemblies: the cytoplasmic sorting platform; the envelope-spanning core/basal body; an exposed needle; and a needle-associated tip complex with associated translocon that is inserted into host cell membranes. The initial subversion of host cell activities is carried out by the effector functions of the invasion plasmid antigen (Ipa) translocator proteins, with the cell ultimately being controlled by dedicated effector proteins that are injected into the host cytoplasm though the translocon. Much of the information now available on the T3SS injectisome has been accumulated through collective studies on the T3SS from three systems, those of Shigella flexneri, Salmonella typhimurium and Yersinia enterocolitica/Yersinia pestis. In this review, we will touch upon the important features of the T3SS injectisome that have come to light because of research in the Shigella and closely related systems. We will also briefly highlight some of the strategies being considered to target the Shigella T3SS for disease prevention

Soluble invasion plasmid antigen C (IpaC) from Shigella flexneri elicits epithelial cell responses related to pathogen invasion

Shigella flexneri invades colonic epithelial cells by pathogen-induced phagocytosis. The three proposed effectors of S. flexneri internalization are invasion plasmid antigens B (IpaB), IpaC, and IpaD, which are encoded on the pathogen's 230-kb virulence plasmid and translocated to the extracellular milieu via the Mxi-Spa translocon. To date, there are no definitive functional data for any purified Ipa protein. Here, we describe the first characterization of highly purified recombinant IpaC, which elicits numerous epithelial cell responses related to events that take place during pathogen invasion. 125I-labeled IpaC binds cultured Henle 407 intestinal cells with an apparent dissociation constant in the low micromolar range. Moreover, incubation of epithelial cells with IpaC results in general changes in cellular phosphoprotein content, demonstrating this protein's ability to influence cellular protein kinase activities. These results contrast dramatically with those seen for recombinant IpaD, which does not bind to or induce detectable changes in the normal activities of cultured epithelial cells. In addition to influencing host cell activities, preincubation of epithelial cells with purified IpaC enhances uptake of S. flexneri by host cells. A similar result is seen when the cells are preincubated with a highly concentrated water extract of virulent S. flexneri 2a (strain 2457T). Interestingly, soluble IpaC also appears to promote uptake of the noninvasive S. flexneri 2a strain BS103. Purified IpaD failed to enhance the uptake of virulent S. flexneri and did not facilitate uptake of BS103. Taken together, the data suggest that IpaC is a potential effector of the host cell biological activities and may be responsible for entry of S. flexneri into target cells

Exploring the Effects of Interaction with a Robot Cat for Dementia Sufferers and their Carers

Research has previously demonstrated the positive effects of robotic companion pets, but while this is important from a research perspective, their cost renders their widespread use currently unfeasible. This research seeks to explore the potential of an affordable robot, with a view to making a realistic difference in quality of life for people with dementia and their carers. Early research results involving participants in the community have proved very positive

In-Game Intoxication: Demonstrating the Evaluation of the Audio Experience of Games with a Focus on Altered States of Consciousness

In this chapter, we consider a particular method of specifically evaluating the user experience of game audio. To provide a domain of game audio to evaluate, we focus on an increasingly occuring phenomenon in game; that of the altered state of consciousness. Our approach seeks to evaluate user experience of game audio from normal gameplay and gameplay that features altered states. As such, a brief background to person-centered approaches to use experience evaluation is presented and then we provide a detailed description of the method that has been adopted in this chapter: the use of personal construct theory via repertory grid interviews

Vegetation patterns and associated hydrogeochemical cycles in a calcareous sloping fen of southwestern Massachusetts.

Calcareous wetlands are rare in New England due to the limited occurrence of limestone-rich bedrock. Because of their great floristic diversity and their support of numerous rare and uncommon plant species, these habitats are targeted for conservation. Little is known about the intricate workings of these ecosystems. This research contributes significantly to understanding the complex biogeochemical relationships that exist between the plant and soil systems in calcareous freshwater wetland environments as a whole. A 3-year field study was initiated in May 1996, to collect data on soils, geochemistry, and hydrology along a 250-m-long transect. Monitoring was concentrated within the rooting zone. Field monitoring and water sampling were conducted biweekly across three growing seasons. Measurements were made for soil-water pH, conductivity, total iron, alkalinity and several dissolved metals. Strong seasonal patterns were observed for several parameters including calcium and iron. Seasonal changes in geochemistry were evaluated using Solmineq.88, a thermodynamic model. In July 1997, soils were sampled adjacent to each replicate instrumentation cluster and standard analyses conducted. Significant differences were measured between the stations for pH, cation exchange capacity, exchangeable calcium, phosphorus, manganese, and biologically available iron. A detailed vegetation analysis was completed in July 1997. High species richness and turnover were measured across the site. Ordination and cluster techniques were used to analyze the vegetation patterns and relate these to environmental site variables. The ordinations suggest that gradients in both soil chemistry (e.g., pH, exchangeable calcium, phosphorus, and iron) and geochemistry (e.g., pH and dissolved calcium) may have strong influences on the vegetation patterns observed in this study. These research results will serve as a baseline for the geochemistry in the greater watershed region, representing a relatively undisturbed system. No fen studies currently exist (for any geographical region) that monitored soil and geochemical parameters throughout the growing season. This research demonstrates the importance of seasonal sampling to describe the cycles present in site biogeochemistry accurately, and it defines several geochemical parameters that strongly influence plant species occurrence and distribution within these environments. This detailed analysis provides valuable information for conservation managers seeking to identify areas for future conservation, preservation, or restoration efforts