Includes bibliography.

Includes bibliography

From simple beginnings, when only one host was required, numerous parasitic organisms have evolved complex life-cycles involving two or more host species. For example, trematode parasites reproduce in vertebrates, their definitive host, but their current life cycle also typically involves two intermediate hosts that were added during the course of evolution. Vertebrates are often considered to be the ancestral hosts of trematodes although other scenarios exist. While multi-host life cycles are observed in distantly related groups of parasites, their evolution remains largely unexplored. In trematodes, while recent phylogenetic studies have shed light on the sequence along which the different hosts were incorporated in the cycle, conditions that favoured the evolution of such complex life cycles can only be hypothesized. However, one opportunity to understand the force shaping the evolution of complex life cycles is provided by the few trematode species in which the classical three-host cycle facultatively reverts to a shorter cycle (i.e. life cycle abbreviation). In this study, the effects of different environmental factors on the life history strategy of the trematode Coitocaecum parvum were investigated using laboratory and field studies. C. parvum is able to abbreviate its life cycle from three to two hosts by maturing early (i.e. progenesis) and producing eggs inside the second intermediate host; both life history strategies occur simultaneously in C. parvum populations. Environmental factors such as predator densities should strongly influence parasite life history strategies. In fact, this study shows that laboratory reared Coitocaecum parvum adopt preferentially the normal three-host cycle when chemical cues from the definitive host are added to their environment, while the shorter cycle is favoured when these cues are absent. However, in nature, multiple environmental factors are likely to be perceived by parasites. Consequently, C. parvum�s ability to adapt its developmental strategy to definitive host densities may be confounded by the complex combination of various environmental parameters. Within-host competition between parasites sharing a common host is also likely to influence individual life history strategies. Parasites could then use alternative life strategies to adaptively respond to intraspecific and interspecific competition. Indeed, this study found that C. parvum preferentially adopts the abbreviated cycle in the presence of competitors. However, in interspecific competition, C. parvum�s strategy also depends upon the competitor species, possibly influenced by the other species� transmission route. Furthermore, intensity of intraspecific competition proved to constrain C. parvum�s ability to use the abbreviated life cycle. Finally, genetic relatedness between co-infecting C. parvum individuals seems to affect parasite life strategy through kin selection: closely related individuals are more likely to adopt the same developmental strategy, when they share a host, than unrelated ones. C. parvum individuals adopting the abbreviated cycle are enclosed within a cyst in their intermediate host and must produce eggs by self-fertilization, the most severe case of inbreeding. It was hypothesized that their offspring would have reduced fitness due to inbreeding depression, therefore selecting against the shorter cycle. However, this study found no difference in the survival and infection success of offspring produced through the abbreviated and normal cycles. Furthermore, no evidence for a genetic basis of life cycle abbreviation was detected: the same proportion of offspring from both reproductive strategies adopted the shorter life cycle. The work in this thesis provides evidence that although life cycle abbreviation provides Coitocaecum parvum with a viable alternative life strategy, numerous factors promote or restrict the adoption of this strategy. While this life history strategy has no detectable effect on parasite fitness, both environmental parameters and within-host competition affect C. parvum life-history strategies, alternatively selecting for either the shorter or normal life cycle. Overall, the complexity of the parasite environment could maintain both developmental strategies in C. parvum populations and, on a broader scale, could have influenced the evolution of complex life cycles in parasites.

The aims of this study were to find endophytic brown algae in marine macroalgae from New Zealand, isolate them into culture and identify them using morphological as well as molecular markers, to study the prevalence of pigmented endophytes in a representative host-endophyte relationship, and to reveal the ultrastructure of the interface between the obligate parasite Herpodiscus durvillaeae (LINDAUER) SOUTH and its host Durvillaea antarctica (CHAMISSO) HARRIOT. Three species of pigmented endophytic Phaeophyceae were isolated from New Zealand macrophytes. They were distinguished based on morphological characters in culture, in combination with their distribution among different host species and symptoms associated with the infection of hosts. ITS1 nrDNA sequences confirmed the identity of two of the species as Laminariocolax macrocystis (PETERS) PETERS in BURKHARDT & PETERS and Microspongium tenuissimum (HAUCK) PETERS. A new genus and species, Xiphophorocolax aotearoae gen. et sp. ined., is suggested for the third group of endophytic Phaeophyceae. Three genetic varieties of L. macrocystis as well as two varieties each of M. tenuissimum and X. aotearoae were present among the isolates. L. macrocystis and X. aotearoae constitute new records for the marine flora of the New Zealand archipelago, on genus and species level. The red algal endophyte Mikrosyphar pachymeniae LINDAUER previously described from New Zealand is possibly synonymous with Microspongium tenuissimum. The prevalence of infection by Laminariocolax macrocystis was investigated in three populations of Macrocystis pyrifera along the Otago coast. Two of the populations situated inside and at the entrance of Otago Harbour showed high infection rates (average between 95 and 100%), while an offshore population was less infected (average of 35%). The phylogenetic affinities of the parasitic brown alga Herpodiscus durvillaeae, an obligate endophyte of Durvillaea antarctica (Fucales, Phaeophyceae) in New Zealand, were investigated. Analyses combined nuclear encoded ribosomal and plastid encoded RuBisCO genes. Results from parsimony, distance and likelihood methods suggest a placement of this species within the order Sphacelariales. Even though H. durvillaeae shows a reduced morphology, molecular data were supported by two morphological features characteristic for the Sphacelariales: the putative presence of apical cells and the transistory blackening of the cell wall with 'Eau de Javelle'. Ultrastructural sections showed evidence for a symplastic contact between the cells of the parasite H. durvillaeae and its host D. antarctica. Within the host cortex, parasite cells attack the fields of plasmodesmata connecting host cells. In these areas, parasite cells squeeze between the host cells and form secondary plasmodesmata connecting the primary plasmodesmata of the host cells with the cytoplasma of the parasite cell. Moreover, despite being described as lacking pigments, H. durvillaeae possesses a rbcL gene, and its plastids show red autofluorescence in UV light, suggesting the presence of a possibly reduced, but functional photosynthetic apparatus. Vestigial walls between developing spores in the 'secondary unilocular sporangia' of H. durvillaeae confirm the identity of these sporangia as plurilocular gametangia, derived from reduced gametophytes which were entirely transformed into gametangia.

Includes bibliographical references (leaves 219-236) / v, 236 leaves : ill. (some col.), plates, photos ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, School of Earth and Environmental Sciences, Discipline of Environmental Biology, 2004

"August 2004" / Bibliography: leaves 146-169. / vi, 169 leaves : ill, (some col.), photos (col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, School of Agriculture and Wine, Discipline of Plant and Pest Science, 2004

<p>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.</p><p> </p><p>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.</p><p> </p><p>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.</p><p> </p><p>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.</p>

<p>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. </p><p>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. </p><p>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. </p><p>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.</p>

Graduation date: 2006

Biology of Scaptomyza apicalis Hardy (Diptera: Drosophilidae) was studied in relation to its host, meadowfoam, Limnanthes alba, a recent oil seed crop grown in the Willamette Valley, Oregon. Populations of flies and larvae were monitored weekly over three consecutive crop-years beginning in 1996. Yellow sticky traps gave relative population estimates of adults. Absolute estimates of larval populations were derived using Berlese funnels to extract immatures from whole plant samples. Weather and crop phenology are key factors in population regulation. Meadowfoams, Limnanthes species, were the only observed hosts for S. apicalis in this study. This has four to five overlapping generations per year. Adults of a small founder population colonize commercial fields coincident with fall rains and seedling emergence. Females deposit eggs in or on plant tissue. Larvae mine leaves and stems. They also bore into crown tissue and flower buds later in the season. Second generation flies arising from the larvae of the founder population first appear in late winter. Successive generations peak during the rapid vegetative growth stage of meadowfoam (mid-April). A steady decline in adult and larval numbers occurs as daily temperatures rise and plants develop flower buds. Last flies are detected in early July when meadowfoam is harvested. Temperatures below 0�� Celsius during December were a key mortality factor for S. apicalis in 1998. Three often major weather components analyzed, accounted for up to 60 percent of the trap count variability. These components were temperature, solar radiation and relative humidity. S. apicalis larvae fed only on plants within the Limnanthes in feeding studies. They accepted nine native meadowfoams but with varying survival rates. The commercial meadowfoam cultivar, Floral, was the most suitable larval host. An increase in supplemental nitrogen fertilizer rates generally resulted in increased infestations of S. apicalis and decreased seed yields. / Graduation date: 2001