Victoria blight of oats is caused by the fungus Cochhobolus victoriae. This fungus is pathogenic due to its ability to produce the host-selective toxin victorin. Previously, a 100-kD protein that binds victorin in vivo only in susceptible genotypes was identified as the P protein of the glycine decarboxylase complex (GDC). Victorin is a potent in vivo inhibitor of GDC. Leaf slices pretreated with victorin displayed an effective Victorin inhibited the concentration for 50% inhibition (EC������) of 81 ��M for GDA. glycine-bicarbonate exchange reaction in vitro with an EC������ of 23 ��M. We also identified a 15-kD mitochondrial protein in susceptible and resistant genotypes that hound victorin. Amino acid sequence analysis indicated this protein is the H protein component of the GDC. Thus, victorin specifically binds to two components of the GDC. Victorin had no detectable effect on GDC in isolated mitochondria, apparently due to the inability of isolated mitochondria to import victorin. The interaction of victorin with the GDC may be central to victorin's mode of action. Supporting this observation is the finding that CO��� gives partial protection against victorin. Elevated CO��� is known to ameliorate the effect of GDC inhibition. Victorin treated plants incubated in the light develop more severe symptoms than dark-incubated plants. Victorin appears to induce a plant-wide signal transduction cascade, resulting in diverse effects. Victorin induces specific proteolytic cleavage of the Rubisco large subunit (LSU). Leaf slices incubated with victorin for 4 hours in the dark accumulate a form of LSU which is cleaved after the N-terminal lysine 14. LSU cleavage in leaf slices is prevented by the protease inhibitors E-64 and calpeptin. LaCl��� prevents this cleavage of LSU and LaCl��� also confers complete protection against victorin at the whole plant level. Victorin also causes lipid peroxidation as measured by MDA accumulation. DNA laddering is seen in leaves after 3 hr treatment with toxin. The ethylene inhibitors AOA and STS give significant protection against victorin at the whole plant level, and also prevent LSU cleavage. / Graduation date: 1998

Graduation date: 1995

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

No description available.

The present study proposes a significant role for host country nationals (HCNs) in the expatriate adjustment process. Based on self-categorizaton theory, newcomer socialization research, organizational citizenship behavior (OCB) research, and models of expatriate adjustment, I present a model proposing how social categorization processes influence HCNs' willingness to engage in adjustment-facilitating organizational citizenship behaviors (AOCBs). I further propose that these behaviors have a significant impact on expatriates' adjustment and in turn, other important job-related outcomes of the expatriate. Hypotheses were tested on 115 expatriates and 53 HCNs. Expatriates were contacted directly or via an organizational contact. HCNs were either contacted directly or nominated by their expatriate counterpart to participate in the study. Results reveal support for the main tenets of the model. The willingness to engage in AOCBs was related to outgroup categorization, collectivism, and perceptions of justice. Social support provided by HCNs was found to significantly relate to HCNs' perceptions of their expatriate co-worker's adjustment. Expatriates, however, indicated that spousal adjustment and language ability were more important for their own adjustment. Adjustment was related to other key expatriate outcomes. The research and managerial implications of these results are discussed.

Cotton (Gossypium hirsutum L.) crop maturity is delayed by cotton fleahopper (Pseudatomoscelis seriatus Reuter) (fleahopper) feeding on early-season fruit forms which increases vulnerability to late-season pests such as Helicoverpa zea (Boddie) and Heliothis virescens (Fabricius). The objectives of this research were to evaluate methods of screening for resistance to fleahopper and to screen selected genotypes. Six fleahoppers were caged on plants in the insectary for 72 h. Numbers of live fleahoppers and percent square damage were determined 48 h following the removal of fleahoppers. Fleahopper numbers and percent square set were determined on randomly selected plants of 16 genotypes when grown under field conditions in 2002 and 2003. Across multiple sampling dates, the number of fleahoppers per plant was higher (p=0.05) in G. arboreum and Pilose (G. hirsutum), but no consistent differences were observed among the remaining 15 genotypes which represented several germplasm pools across the United States. Field and no-choice feeding tests suggested that Pilose, Lankart 142, Suregrow 747, and Stoneville 474 were more resistant hairy-leaf genotypes and not different (p=0.05) in resistance than the smooth-leaf genotypes, Deltapine 50 and TAM 96WD-69s. Pin-head, match-head, and one-third grown squares were removed from plants and placed on agar in petri-plates. Four fleahoppers were released per plate and allowed to feed for 48 h. Fleahopper damage, brown areas along the anthers and/or brown and shrunken pollen sacs was most evident in pin-head sized squares.

To investigate mechanisms involved in virus-host interactions, global changes in host gene expression were examined during infection with adenovirus type 2 (Ad2) using cDNA microarray technology. In paper I and II, transcriptional changes in HeLa cells were investigated during the early and late phase of infection, respectively. A limited number of genes, mainly implicated in cell growth and antiviral defence, were found to be differentially expressed in the early phase, whereas modulation of host cell gene expression during the late phase was augmented and mainly focused on growth inhibition and cell architecture. The experimental set-up was then redesigned to follow transcriptional regulatory events in growth synchronised, human primary lung fibroblasts. The immediate response of the host cell within two hours of infection was investigated in paper III, revealing a transient induction of a small number of cellular alert genes. This was followed by an expanded time course presented in paper IV, which included gene expression profiling at eight consecutive time points throughout the infectious cycle. The results indicated that specific sets of cellular genes were targeted at different stages of the infection, and four distinct periods were identified. In summary, the studies presented in this thesis demonstrate that adenovirus interferes with many cellular processes during the progression of infection to optimize the cellular environment for viral replication. These include cell cycle control, cell growth and growth inhibition, as well as DNA, RNA and protein metabolism. However, a transient induction of cellular genes involved in immune response and growth inhibition was observed before the onset of viral gene expression. During the very late stages of infection, the expression of a large number of genes involved in maintaining the cell structure was down-regulated, presumably to facilitate the spread of progeny virus.

Upplevelseplan för Öckerö Resort lyder underrubriken på denna uppsats. Öckerö Resort är ett kommande resort nära Göteborg som förhoppningsvis inom kort ska öppna portarna för gästerna. Tanken bakom namnet upplevelseplan ligger i fokuset på upplevelser, därav upplevelseplan och inte marknadsplan eller affärsplan. Tre huvudteman kommer vara fundamentet i denna uppsats, som också kommer att genomsyra alla olika delar i uppsatsen. Storytelling, Värdskap och Upplevelseekonomi ska i slutet mynna ut i konkreta förslag på hur Öckerö Resort kan jobba för att tillfredsställa kunden.   Upplevelseekonomi växer i vårt samhälle. Att tillfredsställa kunden blir allt svårare med den högre konkurrensen. Därför bör företag fokusera mer på hur de kan tillfredsställa kunden genom upplevelser. Upplevelseekonomi handlar både om vad man bör erbjuda tillsammans med hur och var man erbjuder det. Öckerö Resort kan erbjuda något i varje del av Pines och Gilmores modell (1999) om hur man definierar en upplevelse, som t ex skiftande design och mat efter årstiderna, fisketurer, föreläsningar och konferensanläggning och avslappning genom ljudböcker i naturen.   Det goda Värdskap handlar om att betjäna kunden och förstå vad denne vill ha och sedan tillfredsställa den önskan. Men för att bedriva det goda värdskapet bör man trivas med det jobb man har, sedan bör man välkomna varandra inom företaget, för att sedan kunna välkomna kunden på ett bra sätt. Storytelling för Öckerö Resort handlar om att försöka berätta något kunden tycker är intressant. En grundarberättelse är det som jag kommit fram till, tillsammans med att marknadsföra sina medarbetare i media genom storys.   I och med att Öckerö Resort bara är i introduktionsstadiet valde jag sekundär empiri, och har försökt ta fram goda exempel för mina tre teman. Google, Island Hotel i Florida och JumboJet på Arlanda är de företag jag anser kan fungera som inspirerande exempel. De typiska dragen för de olika företaget överförs och anspassas sedan till Öckerö Resort situation.

Only two out of more than 200 V. cholerae serogroups, classified on the basis of LPS structure, are associated with epidemic or pandemic cholera. These toxigenic serogroups carry phage-derived pathogenicity islands coding for the main virulence factors for establishment of cholera disease – cholera toxin (CTX) and toxin-coregulated pilus (TCP). The latter also serves as a bacterial surface receptor for the CTXΦ – the filamentous phage which carries the cholera toxin genes into otherwise harmless to human, environmental bacterium V. cholerae. In its natural aquatic habitat V. cholerae is subject to predator grazing, bacteriophage killing, temperature and pH changes, seasonality of plankton blooms and other environmental factors. Therefore understanding V. cholerae pathogenic and virulence potential requires the knowledge of its interaction not only with human host but also members of aquatic environment and environmental factors. V. cholerae is capable of killing the nematode Caenorhabditis elegans. Using a reverse genetics approach, we demonstrated that the quorum sensing regulated protease PrtV is essential for this killing. Other proteases did not seem to contribute to virulence in this model. The data from this study suggest that the PrtV could be important to V. cholerae in its natural niche for its resistance to the grazing predators. The PrtV protease belongs to an M6 family of metallopeptidases which is represented by an Immune Inhibitor A protease from the insect killing bacterium Bacillus thuringiensis. To characterize the protease in more detail, the PrtV was cloned, overexpressed in V. cholerae and purified from the culture supernatant. The enzyme was calcium stabilized and inhibited by metal ion chelators. In tests with in vitro cultured cells of the human intestinal cell line HCT8, the PrtV protein showed a cytotoxic effect leading to cell detachment and death. Using human blood plasma as a source of potential substrates, and by tests with purified candidate substrate proteins, we have identified fibrinogen (all α, β and γ chains), fibronectin and plasminogen to be degraded by the protease. Additionally, PrtV was found to alter the stability of V. cholerae cytolysin implicating its role in modulation of the reactogenicity of V. cholerae secreted factors. Pigmentation has been considered to be important in microbial pathogenesis because it has been associated with virulence in many microorganisms. Using transposon mutagenesis we identified the mutated locus of a pigment producing V. cholerae strain to encode a gene of a tyrosine catabolic pathway. The mutation in a putative homogentisate 1,2-dioxigenase gene lead to accumulation of homogentisic acid, its spontaneous oxidation and formation of a dark pigment. The pigment producing strain was altered in its ability to survive UV exposure and H2O2 stress, and was more efficient in colonizing the suckling mouse intestine compared to the wild type strain. Under the in vitro growth conditions the major virulence factor TcpA and CT expression was found to be somewhat enhanced too.

<p>Despite remarkable strides being made in legislation in South Africa, the country still faces immense challenges which directly impact on the care and protection of its children. Many children are removed from their families and placed into alternative care because of high risk factors in the family and community. However, because of the socioeconomic<br /> situations of families, many of these children will not be able to return to their family. It is, therefore, essential that in the residential care programme, efforts are directed towards permanency planning for each child in order to ensure long term placement in a family. The host parent programme which has been introduced at Child and Youth Care Centres (CYCCs) acts as a precursor to foster-care placements. Following on this, host parents provide the child in need of care with opportunities to interact and form positive relationships with adult caregivers. This study has explored and described, by means of qualitative research, the experiences of host parents who accommodated children in need of care. Nine host parents were purposively selected from three participating CYCCs in Athlone, Cape Town. Data was collected by means of semi-structured individual interviews. The data was analysed according to the steps by Tesch in Creswell (2009). The findings suggest that host parents are instrumental to those children who cannot return to their natural families. The host parents&rsquo / interaction with the CYCC was both positive and negative at times. Recommendations and guidelines in order to develop and improve existing hosting programmes at CYCC&rsquo / s are provided.</p>