Thesis (Ph. D. in Microbiology and Immunology)--Vanderbilt University, Dec. 2006. / Title from title screen. Includes bibliographical references.

No description available.

Rotaviruses are one of the most significant causes of diarrheal disease in the world. Their presence in groundwater and drinking water supplies constitutes a health risk to the population. The study of rotaviruses in the environment has been hampered by the lack of accessible and consistent detection methodologies. Gene probes and other molecular techniques are a novel approach for the detection of these viruses in water. The feasibility of these new techniques for the detection and study of rotaviruses in the environment has been assessed using the simian SA-11 and the culturable human Wa rotavirus strains as models. Two general approaches have been undertaken consisting of hybridization of probes with genomic RNA and hybridization with mRNA produced by the virion-incorporated transcriptase. Hybridization of gene probes with genomic dsRNA of rotaviruses in environmental concentrates resulted in the detection of 10 4 immunofoci of Wa rotavirus. In vitro transcription serves as an amplification method with sensitivity 100- to 1000-fold greater than when probing for genomic RNA. The sensitivity obtained in Wa-seeded distilled water and environmental concentrates after in vitro transcription is 2 and 20 immunofoci, respectively. Proteins in environmental concentrates decrease the efficiency of probe hybridization by 10-100 fold. Also, transcriptase-inhibiting factors found in environmental samples decrease the production of mRNA. Both proteins and transcriptase-inhibiting factors can be reduced significantly with Sephadex G-200 columns. Passage of environmental concentrate through Sephadex G-200 spun columns, followed by in vitro transcription, was used to detect rotaviruses in environmental samples. Rotaviruses were detected by this combination of techniques in eight of 20 sewage samples, one of 16 tap water samples, five of 32 ground water samples, and two of nine surface water samples. Only one of 17 samples which tested positive with Wa cDNA 4 was positive for non-specific probe binding. The probing of rotavirus mRNA, amplified by the virion-incorporated transcriptase, is a practical and feasible method for monitoring these viruses in the environment.

Thesis (Ph. D.)--West Virginia University, 2005 / Title from document title page. Document formatted into pages; contains ix, 155 p. : ill. Vita. Includes abstract. Includes bibliographical references.

Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xi, 288 p. : ill. Vita. Includes abstract. Includes bibliographical references.

The effects of vitamin E (VE) and Arginine (ARG) on humoral and cellular immunity in chickens were investigated in two experiments. The humoral immunity was measured by antibody responses to sheep red blood cells (SRBC) and maternal antibody titers to the infectious bursal disease virus (IBDV), while the cellular immunity was studied using the cutaneous basophil hypersensitivity test to phytogemagglutinin (PHA) and by counting subpopulations of T-lymphocytes. We used two levels of ARG: normal (NARG, 1.2% in feed) and high ARG (HARG, additional 0.3% in drinking water or 1% in feed in experiments 1 and 2, respectively); and three levels of VE were given: 40, 80, and 400 IU/kg feed in experiment 1, and 40, 80, and 200 in experiment 2. / HARG improved the antibody response to SRBC compared with NARG ( P<0.01 for experiment 1 and P<0.013 for experiment 2) 4 days after injection in both experiments. In experiment 1, the VE80 birds maintained higher antibody titers to SRBC (P<0.001) than the VE40 and VE400 birds 4, 8 and 16 d after inoculation. In experiment 2, the antibody titers to SRBC were higher in the VE80 birds compared with the VE200 birds at days 5, 8, and 12 after inoculation (P<0.001). Maternal antibody titers (log10) to the IBDV were higher in the HARG than in the NARG diet in 17-day-old birds (P<0.001) and higher in the VE80 than in the VE40 birds (P<0.001), yet similar to those of the VE200 birds. No interactions were found between ARG and VE. / Naive birds fed HARG exhibited a higher response than NARG birds (P<0.05) to PHA-P at d 17 and to PHA-M at d 41, but, after a second exposure, high ARG levels did not have an effect. Also, in naive birds, the effects of VE were not significant at d 17, but showed an influence after a second exposure in 41-d-old birds. / The percentage of T-helper (Th) and T-cytotoxic (Tc) cells in the blood of 29-d-old birds were not different between ARG levels (P=0.07 and P=0.06, respectively), but Th cells were higher in the VE80 and VE200 birds than in the VE40 birds, and Tc was higher in the VE80 than in the VE40 birds (P=0.02). The B-cell:T-cell ratio was higher in the HARG than the NARG birds (P=0.01) and in the VE40 compared with the VE80 and VE200 birds (P<0.001). Neither ARG nor VE had an effect on the ratio of Th:Tc cells, nor on the percentage of immature T-lymphocytes. / A combination of high levels of ARG and high levels of VE (80 IU/kg of BW) has an important immunomodulation effect on the cellular and humoral immune responses in broiler chickens, improving both maternal antibody titers against the IBDV and antibody titers against SRBC. A combination of ARG and VE increases the proportions of Th and Tc cells, the B-cell:T-cell ratio, and growth performance. The evidence suggests that ARG and VE play complementary and regulatory role on immune response and may enhance the resistance of broilers to infectious diseases. / Key words. Arginine, vitamin E, humoral immunity, cell-mediated immunity, lymphocyte, ELISA. / L'effet de la vitamine E (VE) et l'arginine (ARG) sur les systèmes hummoraireet cellulaire de l'immunité a était évalué chez la volaille dans deux recherches. Lesystème hummoraire de l'immunité a était évalué en utilisant les paramètres tels que laproduction d'anticorps après une injection des globules rouge provenant des moutons(SRBC) et le niveau d'anticorps maternelle après une infection avec les virus causantla maladie 'infectious bursal disease' (lBDV), tandis que les effets sur le systemcellulaire de l'immunité avaient aussi été évalués en utilisant les paramètres comme'cutaneous basophil hypersensitivity test to phytogemagglutinin (PHA)' et endéterminant la concentration des lymphocytes T. Deux concentrations de ARG avaientété utilisées: normale (NARG, 1.2 % de la diète) et une concentration élevée (HARG,additionel 0.3 % dans l'eau ou 1 % dans les diètes); et 3 concentrations de VE: 40, 80et 400 lU/kg dans les diètes dans la première recherche et 40, 80, et 200 lU/kg dans ladeuxième recherche.

Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains x, 202 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

No description available.

The United States is the third-largest producer of raspberries in the world. Washington State leads the nation in red raspberry (Rubus idaeus L.) production. 'Meeker', the most grown red raspberry cultivar in the Pacific Northwest (Washington, Oregon and British Columbia, Canada) is highly susceptible to Raspberry crumbly fruit, a virusinduced disease that produces drupelet abortion and reduces fruit quality and yield. The disease has long been attributed to Raspberry bushy dwarf virus (RBDV), a pollen-and-seed transmitted virus found in most commercial raspberry fields around the world. In recent years, an increased severity of crumbly fruit was observed in areas where two additional viruses were common. One of these viruses, Raspberry leaf mottle virus (RLMV), was characterized recently and shown to be a novel closterovirus transmitted by the large raspberry aphid Amphorophora agathonica Hottes. The second virus, Raspberry latent virus (RpLV) was a tentative member of the family Reoviridae whose characterization remained to be completed. To investigate the role of these two new viruses in the crumbly fruit disorder, 'Meeker' raspberry infected with single or mixtures of the three viruses, in all possible combinations, were generated by graft inoculation. Eight treatments, including a virus free control, were planted in the field at the Northwestern Research and Extension Center in Mt. Vernon, WA. Plant growth and fruit crumbliness were evaluated during establishment and the second year. Simultaneously, the characterization of RpLV, at the genetic and biological level, was completed. RpLV is a novel member of the plant Reoviridae composed of 26,128 nucleotides divided into 10 genomic dsRNA segments. Analysis of the RNA dependent RNA polymerase (RdRP) indicated that RpLV was related most closely to members of the genus Oryzavirus. However, the genomic terminal regions, conserved at the genus level in reoviruses, did not show homology to those of oryzaviruses, suggesting that RpLV may be a member of a new genus. It was found later, that RpLV was transmitted by A. agathonica. As all other plant reoviruses are transmitted by leaf- and planthoppers, these findings strongly support the creation of a new genus in the plant Reoviridae for the classification of RpLV. Real-time quantification of viral titers in single or mixed infections revealed that the titer of RBDV was enhanced ~400-fold when the virus was found in coinfections with RLMV. Interestingly, plants co-infected with these two viruses showed significant reduction in plant growth during the establishment and second year. Crumbly fruit was more severe in plants infected with the three viruses compared to the virus-free control. Taken together, this work presents valuable information about the interactions between three important raspberry viruses and their effect on plant growth and fruit crumbliness in 'Meeker', the most important red raspberry cultivar in the Pacific Northwest. / Graduation date: 2012