Includes bibliography.

Bibliography: leaves 120-145. Reports Bt crystal protein toxicity to a phthirapteran species. Although Bt strain WB3516 may produce other unidentified toxins effective against B. ovis, the results provide strong evidence that the [delta]-endotoxin crystal proteins of strain WB3516 significantly contribute to the lousicidal toxicity of this strain.

La microsporidie, Encephalitozoon cuniculi, parasite intracellulaire, est un pathogène opportuniste. Des reconstructions tridimensionnelles à partir de coupes sériées ont permis de visualiser les différents stades cellulaires au cours de la sporogenèse. L'immunolocalisation de protéines pariétales couplée à l'hybridation in situ des ARNm correspondants ont révélé leur expression différentielle durant le développement intracellulaire. L'étude sur la glycosylation des protéines a permis de démontrer l'absence de N-glycosylation et l'existence d'une voie de O-mannosylation. Semblables à celles des champignons, les chaînes sont linéaires d'une longueur maximale de 8 mannoses liés en alpha1,2 et les mannoprotéines sont localisées dans le capuchon polaire. Des protéines fucosylées sont présentes dans la paroi sporale. La mise au point d'un protocole de séparation des stades sporogoniques en gradient de densité, offre des perspectives d'analyses biochimiques comparatives

<p>Tree sparrows (Passer montanus) have been studied in two areas in Sweden since 1997. At both sites, tree sparrow eggs had remarkably low hatching success. On average only 60% of the eggs hatched. Analyses have shown that this was caused by embryonic mortality, which was highly sex biased. About 70 % of the dead embryos were males, while about 65 % of all fledged nestlings were females. Impaired hatching success here related to two factors. Hatching success was lower for pairs with a male in poor body condition, and it was lower in areas with a high local population density. </p><p>A sex bias in the mortality early in life has been demonstrated in several species. Since the competitive ability of males is determined by conditions early in life, parents with poor provisioning capacity should prefer to produce female offspring in broods reared under poor conditions. The body condition of a tree sparrow during the nestling stage was well correlated to the condition as an adult, and pairs in which the male parent was in poor condition produced chicks in poor condition. Since the breeding success of a pair depended more on the condition of the male, females appear less affected by conditions early in life. Parents with poor provisioning capacity appear to bias offspring survival towards females, and a difference in the early susceptibility may be adaptive. </p><p>Changes in birth sex ratios have in some cases been suspected to result from exposure to estrogenic environmental pollutants. This was examined by exposing great- and blue tit embryos to a synthetic estrogen. Although there was a difference in the mortality rate, the difference was present also in the control groups, why this could not be attributed to estrogen exposure.</p>

The microsporidian parasite Nadelspora canceri infects Dungeness crabs, Cancer magister, along the United States Pacific Northwest coast. The prevalence and seasonal variation of N. canceri in Dungeness crabs from Alsea Bay, Oregon, are described based on examination of 2991 crabs collected at monthly intervals from October, 1991 to June, 1993. The average prevalence in monthly samples was 21.0% and ranged from 8.2% to 33.0%. No significant differences in monthly or seasonal parasite prevalence were observed. A total of 3061 Dungeness crabs was examined from an additional seven Pacific Northwest estuaries and Puget Sound to document the geographic distribution of N. canceri and the prevalence of the parasite in these locations. The estuaries sampled and the prevalences observed were: Humboldt Bay, California (14.6%), Coos Bay (10.6%), Yaquina Bay (2.0%), Tillamook Bay (41.2%), and Nehalem Bay, Oregon (14.2%), Willapa Bay (6.9%), and Grays Harbor Washington (0.44%). Dungeness crabs were examined from the Dungeness spit, Kala Point, and Mukilteo areas in Puget Sound and no infected crabs were found. A total of 9317 male Dungeness crabs > 15.9 cm carapace width (CW) captured in the commercial ocean crab fishery was examined for N. canceri and 27 (0.3%) were infected with the parasite. No infections were found in crabs smaller than 3.0 cm CW and the prevalence of infection generally increased with crab size reaching a peak of 22.2% in 14 cm CW crabs. The overall infection prevalence in male crabs (19.2%) was more than twice that of female crabs (8.0%), and of the 821 infected crabs found, 629 (76.6%) were males. The mortality of laboratory-held Dungeness crabs naturally infected with N. canceri was compared to that of uninfected crabs in two separate experiments and in both cases a significantly higher mortality was observed for infected crabs. Nadelspora canceri infections were established in both juvenile and adult Dungeness crabs that were fed parasite spores in laboratory experiments indicating that transmission is direct and intermediate hosts or vectors are not required for transmitting the parasite between hosts. / Graduation date: 1995

Myxobolus cerebralis, a myxozoan parasite of salmonids, is the causative agent of whirling disease. The parasite is considered widespread throughout northeastern Oregon in the Grande Ronde and Imnaha River basins where threatened and endangered salmonid populations exist. The work presented in this thesis comprises several studies that assess the effects of M. cerebralis on resident and anadromous salmonids in Oregon. Laboratory challenges to determine the susceptibility of indigenous Deschutes River, Oregon, salmonids to M. cerebralis were conducted as part of a study to assess the risk of reintroducing anadromous salmon above a migration barrier on that river. This study was the first to assess the susceptibility of kokanee salmon Oncorhynchus nerka to M. cerebralis, and results contribute to the understanding of salmonid susceptibility as it relates to species and age. Further, this study demonstrates that the indigenous salmonids present in the river are susceptible to infection, but resident rainbow trout Oncorhynchus mykiss would be most at risk should introduction of M. cerebralis occur in this system. The susceptibility of chinook salmon Oncorhynchus tshawytscha to M. cerebralis was assessed following laboratory challenges at different ages to different parasite levels. Results from this study indicate that chinook salmon are more resistant to M. cerebralis infection than susceptible rainbow trout; resistance to disease developed in chinook salmon exposed after 3 weeks of age. Sustained exposures to a low parasite dose were performed to model the conditions chinook salmon would encounter in a natural exposure. Following continuous exposure to low parasite densities, chinook salmon were very resistant to infection and disease. Managed populations of chinook salmon and steelhead Oncorhynchus mykiss juveniles are held in acclimation facilities on their natal streams before release to commence their seaward migration. Rainbow trout fry were held at each of the acclimation facilities to detect the presence of M. cerebralis and to assess the prevalence of exposure during the acclimation period. Results from these exposures indicate that the Wallowa acclimation facility is a high-risk site for parasite exposure of steelhead juveniles. Further, detection was confirmed in several rivers and streams where the presence of M. cerebralis has been suggested. Finally, a preliminary study on the effect of M. cerebralis on survival of steelhead juveniles upon transfer to saltwater was conducted. Results from this study indicate that M. cerebralis exposure and infection may increase mortality among juvenile steelhead during saltwater adaptation. / Graduation date: 2003

Calow (1983) realized that differences between parasites and their free-living relatives can be explained by the differences in nutrient richness. I propose a model that is based on Calow's idea which identifies the relative position of different trophic strategies (e.g. predation, grazing, parasitism and others) based on (1) the differences by which consumers arrive at their intrinsic rate of growth, and (2) the ecological impact they inflict on their hosts. I hypothesize that trophic interactions can be clarified if a parameter is included that takes into account the host's/prey's fate in the interaction. Moreover, this model suggests specific trophic evolutionary pathways (TEPs) between each strategy, and suggests that some pathways are more likely than others. In particular, parasitoidism is believed to be a highly derived strategy, and the TEPs presented in the model suggest parasitoidism could have arisen from either a predator-like or a typical-parasitic ancestor. Though the trophic categories determined by the model seem intuitive, this approach does provide, apparently for the first time, an objective, mathematically and ecologically useful basis for classifying animal trophic relationships. / Graduation date: 1998

Im Rahmen des ersten Teils der vorliegenden Doktorarbeit konnten zwei nicht-essentielle (rps15, rpl36) und fünf essentielle (rps3, rps16, rpl22, rpl23, rpl32) im Plastom von Nicotiana tabacum kodierte Proteine des plastidären Ribosoms bezüglich ihrer Essentialität charakterisiert werden. Diese Gene wurden durch gezielte Knockout-Experimente inaktiviert und die resultierenden Effekte untersucht. Die Ergebnisse lassen einen Rückschluss auf die Lokalisation der Gene der insgesamt sieben untersuchten ribosomalen Proteine zu, die im Plastom mehrerer parasitischer, Plastiden-besitzender Spezies nicht mehr nachweisbar sind. Im Fall von rps15 könnte tatsächlich ein Verlust des Genes stattgefunden haben, im Fall der restlichen Gene ist eher mit einem Transfer in den Nukleus zu rechnen (rpl36 ausgenommen). Dies würde bedeuten, dass die Geschwindigkeit der erfolgreichen Etablierung eines Gentransfers in vielen parasitischen Spezies gegenüber grünen Pflanzen stark erhöht ist. Alle in E. coli nicht-essentiellen Proteine mit Homologen in Plastiden (rps15, rpl33, rpl36) sind auch dort, trotz ~1,5 Milliarden Jahren getrennter Evolution, nicht essentiell. Dieses Ergebnis bestätigt den schon früher festgestellten hohen Konservierungsgrad der bakteriellen und plastidären Translationsmaschinerien. Die Phänotypen der KO-Pflanzen der nicht-essentiellen Gene (rps15, rpl36) weisen auf eine interessante Rolle von S15 während der Ribosomenassemblierung hin und im Fall von L36 auf eine wichtige funktionelle Rolle im Plastiden-Ribosomen sowie auf eine Involvierung der Plastidentranslation in der Generierung eines retrograden Signals, welches die Blattform zu beeinflussen im Stande ist. Des Weiteren konnte eine Verbindung der Translationsaktivität mit der Ausbildung von Seitentrieben hergestellt werden, die vermutlich auf veränderte Auxinsynthese im Chloroplast zurückzuführen ist. Aus dem Folgeprojekt, bei dem Doppel-KO-Pflanzen nicht-essentieller ribosomaler Proteine erzeugt wurden, lässt sich auf eine relativ große Plastizität der Architektur von Plastidenribosomen schließen. Im zweiten Teil der Arbeit konnte erfolgreich ein Hochdurchsatz-Screeningsystem zur semiquantitativen Analyse von 192 verschiedenen miRNAs aus Chlamydomonas reinhardtii etabliert werden. Es gelang durch die Untersuchung von 23 verschiedenen Wachstums- und Stressbedingungen sowie Entwicklungsstadien mehrere miRNAs zu identifizieren, die eine differenzielle Expression zeigen sowie unter allen untersuchten Bedingungen konstant bleibende miRNAs nachzuweisen. Dadurch konnten mehrere vielversprechende Kandidaten-miRNAs ausgemacht werden, die nun eingehender untersucht werden können. / Plastid genomes of higher plants contain a conserved set of ribosomal protein genes. Although plastid translational activity is essential for cell survival in tobacco (Nicotiana tabacum), individual plastid ribosomal proteins can be nonessential. Candidates for nonessential plastid ribosomal proteins are ribosomal proteins identified as nonessential in bacteria and those whose genes were lost from the highly reduced plastid genomes of nonphotosynthetic plastid-bearing lineages (parasitic plants, apicomplexan protozoa). Here we report the reverse genetic analysis of seven plastid-encoded ribosomal proteins that meet these criteria. We have introduced knockout alleles for the corresponding genes into the tobacco plastid genome. Five of the targeted genes (ribosomal protein of the large subunit22 [rpl22], rpl23, rpl32, ribosomal protein of the small subunit3 [rps3], and rps16) were shown to be essential even under heterotrophic conditions, despite their loss in at least some parasitic plastid-bearing lineages. This suggests that nonphotosynthetic plastids show elevated rates of gene transfer to the nuclear genome. Knockout of two ribosomal protein genes, rps15 and rpl36, yielded homoplasmic transplastomic mutants, thus indicating nonessentiality. Whereas Δrps15 plants showed only a mild phenotype, Δrpl36 plants were severely impaired in photosynthesis and growth and, moreover, displayed greatly altered leaf morphology. This finding provides strong genetic evidence that chloroplast translational activity influences leaf development, presumably via a retrograde signaling pathway. In the second project a qRT-PCR based plattform for the analysis of miRNAs in Chlamydomonas reinhardtii has been developed. 20 different growth conditions have been scanned.

Tree sparrows (Passer montanus) have been studied in two areas in Sweden since 1997. At both sites, tree sparrow eggs had remarkably low hatching success. On average only 60% of the eggs hatched. Analyses have shown that this was caused by embryonic mortality, which was highly sex biased. About 70 % of the dead embryos were males, while about 65 % of all fledged nestlings were females. Impaired hatching success here related to two factors. Hatching success was lower for pairs with a male in poor body condition, and it was lower in areas with a high local population density. A sex bias in the mortality early in life has been demonstrated in several species. Since the competitive ability of males is determined by conditions early in life, parents with poor provisioning capacity should prefer to produce female offspring in broods reared under poor conditions. The body condition of a tree sparrow during the nestling stage was well correlated to the condition as an adult, and pairs in which the male parent was in poor condition produced chicks in poor condition. Since the breeding success of a pair depended more on the condition of the male, females appear less affected by conditions early in life. Parents with poor provisioning capacity appear to bias offspring survival towards females, and a difference in the early susceptibility may be adaptive. Changes in birth sex ratios have in some cases been suspected to result from exposure to estrogenic environmental pollutants. This was examined by exposing great- and blue tit embryos to a synthetic estrogen. Although there was a difference in the mortality rate, the difference was present also in the control groups, why this could not be attributed to estrogen exposure.

Chronic wasting disease (CWD) was detected in Saskatchewan wild deer populations in 2000 which prompted disease management actions consisting of population reduction. Little is known about population structure, health status, interactions or movement patterns of deer in Saskatchewan and these factors are important in designing a management program for CWD. As part of an ongoing study on deer movement patterns of wild deer in southern Saskatchewan, a survey was conducted to: 1) determine prevalence of CWD and selected infectious agents in mule deer (Odocoileus hemionus) and white-tailed deer (Odocoileus virginianus), and 2) identify infectious agents which could be used as a surrogate measure of the effectiveness of the adopted CWD management strategies. Tonsil biopsies, feces and blood were collected from 254 mule deer and 43 white-tailed deer during winters of 2006, 2007 and 2008. Immunohistochemical staining of tonsil biopsies for CWD revealed a prevalence of 2.4% (6/249) in mule deer and 0% (0/43) in white-tailed deer. Parasitological investigation of 253 fecal samples from mule deer identified eggs of nematodes in the superfamily Trichostrongyloidea (29.2%); and parasitic stages of the following genera: Nematodirus (7.1%), Skrjabinema (14.3%), Trichuris (0.8%), Moniezia (16.2%), Thysanosoma (12.2%), Orthostrongylus (35.2%), Eimeria (13.4%) and Giardia (0%, 0/137). A similar investigation of 42 white-tailed deer fecal samples identified parasitic stages of nematodes in the super family Trichostrongyloidea (4.8%) and in genera of Orthostrongylus (2.4%), Moniezia (2.4%) and Eimeria (2.4%). Dorsal-spined larvae were detected in 2.4% of the white-tailed deer fecal samples. In serum samples from 253 mule deer, antibodies (Ab) were detected against bovine herpesvirus1 (BoHV-1) (34.8%), parainfluenza-3 (PI-3) (56.5%), bovine virus diarrhoea virus (BVDV-1) (30.8%) and Neospora caninum (15.4%, 36/245). In serum samples from 40 white-tailed deer, Ab to BoHV-1(32.5%), PI-3 (35%), BVD-1 (12.5%) and Neospora caninum (20.5%, 8/39) was detected. Based on relative host specificity, moderate prevalence and horizontal routes of transmission, herpesvirus, parainfluenza 3, Eimeria and Skrjabinema were identified as infectious agents which could potentially be used to evaluate the effectiveness of disease management strategies, which may in turn predict the response of CWD to these same strategies. Using polymerase chain reaction (PCR) a herpesvirus was detected, in 42.1% (40/95) of retropharyngeal lymph nodes from hunter-submitted mule deer and white-tailed deer heads from Saskatchewan in 2007. DNA sequences of the partial DNA polymerase gene from this virus were 98 - 100% identical to mule deer lymphotropic herpesvirus (mule deer-LHV). A 3.6 kb contiguous sequence of mule deer-LHV genome was generated by genome walking (GenBank Accession number: HM014314). Use of a mule deer-LHV-specific PCR on buffy coat samples collected during winters of 2007 and 2008, detected mule deer-LHV in 42.1% (67/158) of mule deer and 33.3% (8/24) of white-tailed deer. Very little DNA sequence diversity in the partial sequences of glycoprotein B (gB) gene and the intergenic spacer regions between DPOL and gB gene of mule deer-LHV was observed among deer from different wildlife management zones. Mule deer-LHV is also a potential marker for evaluating the effectiveness of disease management activities because of its moderate prevalence, host specificity, ease of sample collection and the availability of a rapid and low-cost method for its detection. A variable region of the mule deer-LHV genome needs to be identified if this virus to be used as an inferential tool for studying host population structure.