Search results for "PET"
showing 10 items of 12749 documents
Prevalence of infection as a predictor of multiple genotype infection frequency in parasites with multiple-host life cycle.
2012
In nature, parasites commonly share hosts with other conspecific parasite genotypes. While adult parasites typically show aggregated distribution in their final hosts, aggregation of clonal parasite genotypes in intermediate hosts, such as those of trematodes in molluscs, is not generally known. However, infection of a host by multiple parasite genotypes has significant implications for evolution of virulence and host-parasite coevolution. Aggregated distribution of the clonal stages can increase host mortality and reduce larval output of each infecting genotype through interclonal competition, and therefore have significant implications for parasite epidemiology. The aim of this study was …
Interactive effects between diet and genotypes of host and pathogen define the severity of infection
2012
Host resistance and parasite virulence are influenced by multiple interacting factors in complex natural communities. Yet, these interactive effects are seldom studied concurrently, resulting in poor understanding of host-pathogen-environment dynamics. Here, we investigated how the level of opportunist pathogen virulence, strength of host immunity and the host condition manipulated via diet affect the survival of wood tiger moth Parasemia plantaginis (Arctidae). Larvae from “low cuticular melanin” and “high cuticular melanin” (considered as low and high pathogen resistance, respectively) selection lines were infected with moderately and highly virulent bacteria strains of Serratia marcescen…
Influence of Two N-Fixing Legumes on Plant Community Properties and Soil Nutrient Levels in an Alpine Ecosystem
2013
Abstract Low nitrogen (N) supply is a limiting factor for plant growth in most terrestrial ecosystems. N-fixing legumes therefore have the potential to facilitate surrounding vegetation by increasing soil N levels. This effect should be especially pronounced in low-productivity habitats where ambient soil N levels are low, such as in alpine areas. We examined whether plant species composition, community diversity measures, and soil N levels differed with and without the presence of two alpine legumes, Oxytropis lapponica (Wahlenb.) Gay and Astragalus alpinus L., in a Dryas octopetala heath at Finse, Norway. Species composition and richness differed between plots with and without Oxytropis i…
Antibiotics accelerate growth at the expense of immunity
2021
Antibiotics have long been used in the raising of animals for agricultural, industrial or laboratory use. The use of subtherapeutic doses in diets of terrestrial and aquatic animals to promote growth is common and highly debated. Despite their vast application in animal husbandry, knowledge about the mechanisms behind growth promotion is minimal, particularly at the molecular level. Evidence from evolutionary research shows that immunocompetence is resource-limited, and hence expected to trade off with other resource-demanding processes, such as growth. Here, we ask if accelerated growth caused by antibiotics can be explained by genome-wide trade-offs between growth and costly immunocompete…
Acquired resistance triggered by elicitins in tobacco and other plants
1996
Elicitins are a family of proteins excreted byPhytophthora spp. They exhibit high sequence homology but large net charge differences. They induce necrosis in tobacco plants which then become resistant to the tobacco pathogenPhytophthora parasitica var.nicotianae. In stem-treated plants, resistance was not restricted to the site of elicitin application, but could be demonstrated by petiole inoculation at all levels on the stem. Resistance was already maximum after two days and lasted for at least two weeks. It was effective not only towardsP. p. var.nicotianae infection, but also against the unrelated pathogenSclerotinia sclerotiorum. In contrast to dichloroisonicotinic acid, an artificial i…
Trophic interactions between introduced lake trout (Salvelinus namaycush) and native Arctic charr (S. alpinus) in a large Fennoscandian subarctic lake
2014
Introduced fishes may have major impacts on community structure and ecosystem function due to competitive and predatory interactions with native species. For example, introduced lake trout (Salvelinus namaycush) has been shown to replace native salmonids and induce major trophic cascades in some North American lakes, but few studies have investigated trophic interactions between lake trout and closely related native Arctic charr (S.alpinus) outside the natural distribution of the former species. We used stomach content and stable isotope analyses to investigate trophic interactions between introduced lake trout and native Arctic charr in large subarctic Lake Inarijarvi in northern Finland. …
Effect of ambient temperature variations on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella
2019
[EN] Two outdoor photobioreactors were operated to evaluate the effect of variable ambient temperature on an indigenous microalgae-nitrifying bacteria culture dominated by Chlorella. Four experiments were carried out in different seasons, maintaining the temperature-controlled PBR at around 25¿°C (by either heating or cooling), while the temperature in the non-temperature-controlled PBR was allowed to vary with the ambient conditions. Temperatures in the range of 15¿30¿°C had no significant effect on the microalgae cultivation performance. However, when the temperature rose to 30¿35¿°C microalgae viability was significantly reduced. Sudden temperature rises triggered AOB growth in the indig…
Convergences and divergences between scientific and Indigenous and Local Knowledge contribute to inform carnivore conservation
2021
There is increasing recognition that diverse knowledge systems can work in mutually enriching ways and that Indigenous and Local Knowledge (ILK) can enhance biodiversity conservation. However, studies using scientific knowledge and ILK in a complementary manner, and acknowledging convergent and especially divergent insights have remained limited. In this study, we contrasted proxies of abundances and trends of threatened and conflict-prone carnivores (caracal, cheetah, jackal, lion, leopard, spotted hyaena, striped hyaena) derived separately from scientific knowledge and ILK. We conducted camera trapping, track surveys and semi-structured interviews with local pastoralists from northern Ken…
Larval intraspecific competition for food in the European grapevine moth Lobesia botrana.
2014
AbstractEffective pest management with lower amounts of pesticides relies on accurate prediction of insect pest growth rates. Knowledge of the factors governing this trait and the resulting fitness of individuals is thus necessary to refine predictions and make suitable decisions in crop protection. The European grapevine moth, Lobesia botrana, the major pest of grapes in Europe, is responsible for huge economic losses. Larvae very rarely leave the grape bunch on which they were oviposited and thus cannot avoid intraspecific competition. In this study, we determined the impact of intraspecific competition during the larval stage on development and adult fitness in this species. This was tes…
Nomenclatural synopsis of cirsium sect. Eriolepis (asteraceae) in Italy
2021
The names of the Italian taxa in Cirsium sect. Eriolepis are discussed. The accepted names are: Cirsium echinatum, C. eriophorum subsp. eriophorum, C. eriophorum subsp. spathulatum, C. ferox, C. italicum, C. lacaitae, C. lobelii, C. morisianum, C. scabrum, C. tenoreanum, C. vallis-demonii subsp. vallis-demonii, C. vallis-demonii subsp. calabrum comb. nov., and C. vulgare (= C. crinitum, C. sylvaticum). Four accepted names are typified by specimens preserved at FI (one lectotype), G (one lectotype and one neotype), P (one lectotype), and by illustrations (two lectotypes). Several other heterotypic synonyms of taxa described from Italy are discussed and six of them are typified. A new combina…