Nutritional Immunomodulation as an Approach to Decreasing the Negative Effects of Stress in Poultry Production

Stress can lead to changes in the immune response resulting in both increased and decreased resistance to opportunistic bacterial pathogens. Growth-promoting antibiotics have been a major tool in modulating hostpathogen interactions and limiting clinical and subclinical bacterial infection in confined animal production. Regulatory pressures to limit antibiotic use in poultry production and recent international marketing agreements that prohibit treating poultry with antibiotics have limited the disease-fighting tools available to poultry and livestock producers, particularly in Europe. There is a need to evaluate potential antibiotic alternatives to improve both production and disease resistance in high-intensity food animal production. Nutritional approaches to counteract the debilitating effects of stress and infection may provide producers with useful alternatives to antibiotics. Improving disease resistance in food animals, particularly in the absence of antibiotic treatment, is a key strategy in the effort to increase food safety. ARS research has demonstrated the efficacy of several nutritional immunomodulators, including vitamin D3 and yeast cell wall products, to protect against bacterial infection due to stress and challenge with opportunistic pathogens. These studies also provide an animal model for testing the efficacy of nutritional strategies that may affect the response to stress and related infection in humans

Critical Evaluation of Bacteriophage to Prevent and Treat Colibacillosis in Poultry

There is a continuing need to find alternatives to antibiotics in animal and human medicine. Bacteriophages are viruses that infect and kill bacteria, with no known activity to plant and animal cells. We have conducted research to critically evaluate the efficacy of bacteriophage to both prevent and treat colibacillosis in poultry. Bacteriophages lytic to an Escherichia coli pathogenic to poultry were isolated from municipal waste water treatment plants and poultry processing plants. Two bacteriophage isolates were selected to use in studies designed to determine the efficacy of these bacteriophage to prevent and treat severe colibacillosis in poultry. Colibacillosis was induced by injecting 6 X 104 cfu of E. coli into the thoracic airsac when the birds were 1 week of age. Initial studies demonstrated that mortality was significantly reduced when the challenge culture was mixed with bacteriophage prior to challenging the birds. In subsequent studies, we have shown that an aerosol spray of bacteriophage given to the birds prior to this E. coli challenge can prevent the disease, and that an intramuscular injection of bacteriophage provides an effective treatment of this disease. We have demonstrated that bacteriophage can be used to both prevent and treat colibacillosis in poultry and may provide an effective alternative to antibiotic use in animal and human medicine

Tensions of Integration in Professional Formation: Investigating Development of Engineering Students\u27 Social and Technical Perceptions

Tensions of Integration in Professional Formation: Investigating Development of Engineering Students\u27 Social and Technical PerceptionsTwenty-first century engineers face incredible challenges and opportunities, many of which aresocially complex, transcending the traditional “technical” boundaries of engineering. Thetechnology produced by engineers must not only function as predicted by mathematical andtheoretical models but must also operate beneficially and seamlessly in complex social contexts.In this sense, engineers must embody an integrated social and technical – or sociotechnical –identity rather than a dualistic social/technical one.A growing body of scholarship has discussed how dominant cultures of engineering shapestudents’ and professionals’ understandings of social and technical dimensions of their work.Further, engineering education research has advanced understanding of how engineering identityis formed by external, structural forces. Yet, from a psychological perspective, we know littleabout how engineering students come to perceive and embody their identities as engineers,especially in relation to social and technical dimensions of these identities. Thus, we organizedthis study around the following research questions.RQ0: How do students psychologically experience identity trajectories of becoming engineers?RQ1: How do students perceive the social and technical features of engineering identity?RQ2: How do students internally experience their identities as engineers, particularly with regard to social and technical dimensions of these identities?RQ3: How do social and technical perceptions of their engineering identity develop and change in the course of the engineering curriculum or in the transition to the workplace?To respond to these research questions, we have conducted two longitudinal studies usinginterpretative phenomenological analysis (IPA). One study focused on graduating seniors as theytransitioned into the workplace, and the second study focused on first-year students transitioningto engineering degree coursework. These investigations produced robust and nuancedunderstanding of students’ engineering identity trajectories throughout and beyond thecurriculum. These findings are being leveraged in order to provide our initial understanding in athematic analysis on sophomore engineering students.Thus far, the findings of the investigation highlight the complexity of becoming both engineers,specifically by demonstrating a somewhat contradictory relationship between what participantsperceived to be engineering and how they actually embodied an engineering-self. They furtherdemonstrate the manifold ways that participants realized and prioritized identities outside ofengineering and how these multiple selves interacted in ways that affected their engineeringidentities. Additionally, findings for both male and female groups suggest that somepsychological patterns might be related to gender. In sum, the findings depict a complex pictureof engineering-students-turned-engineers as whole persons. By focusing on how engineeringidentity development is embodied, the findings generate multiple theoretical insights that bearrelevance for engineering education research and provocative implications that bear significancefor engineering educators, students, and employers

Identification of Functional Platelet-Activating Factor Receptors on Human Keratinocytes

Platelet-activating factor (PAP) is a potent inflammatory mediator that has been shown to be produced by human keratinocytes and is thought to play a role in cutaneous inflammation, Immunofluorescence and radioligand binding studies were used to characterize PAP receptors (PAF-R) on human keratinocytes and the human epidermoid cell lines A-431 and HaCaT. Indirect immunofluorescence studies demonstrated anti-PAF-R staining of primary cultures of human keratinocytes, A-431 cells, and HaCaT cells, Primary cultures of human fibroblasts and the melanoma cell line SK-30 failed to show immunostaining above that seen with control antiserum. With indirect immunofluorescence studies of sections of normal human skin, a granular anti-PAF-R staining pattern was noted on the keratinocyte cell membranes. A-431 cells readily metabolized PAF by deacetylationreacylation at 37°C, but not at 4°C. Binding studies on crude membrane preparations of A-431 cells conducted at 4°C demonstrated specific binding that reached saturation by 120 min. Scatchard analysis of PAF binding data revealed a single class of high-affinity (KD = 6.3 ± 0.3 nM) PAP binding sites, The immunofluorescence and radioligand binding sites were shown to be functional PAF-Rs, as 10 pM to 1 μM PAF increased intracellular calcium in primary cultures of human keratinocytes, A-.431 cells, and HaCaT cells, whereas PAF treatment of primary cultures of human fibroblasts or the melanoma cell line SK-30 did not result in changes in the intracellular calcium concentration. The structurally dissimilar PAF-R antagonists CV-6209, Ro19-3704, and alprazolam all inhibited the PAF-induced calcium changes in A-431 cells, The CV-6209 inhibition was seen at doses that competed with the PAF binding to these cells. These studies provide the first evidence for the presence of a functional PAF-R expressed on human keratinocytes, suggesting that this lipid mediator may play an important role in normal keratinocytes or in inflammatory dermatology