Over the last 60 years, grass tetany has been recognised as a significant lethal condition in sheep and cattle.Outcomes from this study include documentation of the likely precursors to grass tetany, ways to recognise these precursors, and long term practices that will enable producers to minimise livestock deaths. The benefit of this research to beef producers is that the environmental circumstances thought to be associated with outbreaks of grass tetany have been identified, along with remedial action that can be taken to prevent deaths occurring.Recommendations to industry on best practice to be adopted by leading producers to minimise outbreaks of grass tetany are made.This study provides an alternate strategy for the management of grass tetany in beef cattle, to the more clinical approaches previously recommended. It is suggested that losses from this economically important metabolic disease can be minimised if management practices of beef cattle producers in eastern Australia can incorporate a more holistic approach to farm management, which takes account of the soil/plant/animal/climate inter-relationships. / Master of Science (Hons)

Serratia entomophila, the causative agent of amber disease, is an endemic bacterium used for the biocontrol of New Zealand grass grub larvae. Although the available biopesticide is effective, its use is limited to areas where sub-surface application is feasible, and is also impacted by soil conditions such as moisture levels and osmolarity. The aim of this study was to elucidate the responses of S. entomophila to osmotic and desiccation stresses in relation to challenges encountered during production, storage and soil application, with the goal of developing a more robust and versatile biocontrol agent. RpoS is a key factor in the stress response of many enteric bacteria. In order to dissociate the effect of RpoS from subsequent cellular stress studies, an rpoS mutant was constructed by site-directed mutagenesis. Assessment of the rpoS mutant showed that RpoS was not implicated in NaC1 or desiccation tolerance of S. entomophila. The rpoS mutant was instead found to have enhanced salt tolerance and could be distinguished from the wild-type by the ability to ferment arabinose, a phenotype that was confirmed through complementation. Complete abolition of the amber disease process was observed using an rpoS strain also missing the Sep virulence genes, suggesting that RpoS is a regulator of the S. entomophila anti-feeding prophage (Afp). These findings indicate a subtle interplay between NaC1 tolerance, virulence and RpoS-mediated regulation of amber disease in S. entomophila. A transposon mutagenesis screen was carried out to identify genes associated with NaC1 tolerance in S. entomophila. Fourteen mutants displaying NaC1 sensitivity were identified, two of which had mutations in genes with potential implications for the formulation of the bacterium as a biocontrol agent. The gene leuO that encodes a LysR-family transcriptional regulator was found to be essential for S. entomophila NaC1 tolerance. The toxicity of increased cellular LeuO from an over-expression vector led to the investigation of the effects of leuO mutation on the proteome. Multiple protein changes observed by two-dimensional gel analysis suggested that LeuO may be a global regulator in S. entomophila, as has been hypothesised for Salmonella species. A second NaC1-sensitive mutant contained an insertion in afp15, the product of which is thought to be involved in assembly of the Afp. As well as being sensitive to NaC1, the afp15 mutant was unable to induce the anti-feeding component of amber disease, again highlighting the link between stress tolerance and virulence in S. entomophila. This study also determined that pre-exposure to NaC1 in conjunction with the provision of exogenous glycine betaine significantly enhanced the survival of S. entomophila either in a desiccated state or after application to soil, regardless of the soil moisture content. The implication of this finding on the future formulation of S. entomophila led to investigation of the underlying genetic mechanisms involved in glycine betaine synthesis and NaC1 tolerance. The genes involved in glycine betaine biosynthesis from choline were identified through genomic comparison, degenerate PCR and primer walking. A 6.5 kb region was sequenced and found to contain four genes with homology and similar chromosomal arrangement to the E. coli bet genes (betTIBA). The S. entomophila betIBA genes comprised an operon, flanked by the divergently-transcribed betT gene whose product is responsible for choline transport. To ascertain the relative transcription levels of components of the bet operon, quantitative RT-PCR was performed. Results of qRT-PCR showed that choline in conjunction with NaC1 induced the greatest levels of bet gene transcription, and that levels of the betA transcript were significantly lower than those of the other bet genes. Examination of the betA 5� non-coding region identified a previously undetected hairpin region, possibly accounting for the observed decrease in betA transcript levels. The findings of this study have significantly advanced our understanding of how S. entomophiia responds to stress, and will contribute to the development of formulation strategies for the production of a robust product capable of application to pasture by a range of teclmiques. In addition, there is significant potential to utilise these findings in the development of other bacterial inocula for a range of biotechnological applications.

<p> </p><p>Many of Europe’s day-living butterflies have shown decreasing populations during the last decades and many species are threatened. Many butterflies are dependent on managed semi-natural grasslands because of their richness in nectar sources and host plants for the butterfly larva. Swedish pastures are mostly managed through grazing. The number of cattle in Sweden have been decreasing while the number of sheep in the country increased by 30%. I examined if there was any differences in the butterfly and herb species diversity between pastures grazed by cattle or sheep. During the fieldwork, ten structurally similar pastures in the vicinity of Linköping, Östergötland were studied. Grazing by cattle was favourable both for butterfly and herb species with respect to species richness. Larger amounts of grass biomass and ground coverage by grass were in this study linked to sheep grazing. There have earlier been proposed that sheep graze more selective on herbs in favour of grass, with decreasing amounts of herbs and increasing amounts of grass in sheep grazed pastures, as a result. This theory is confirmed in this paper. The hypothesis that lower amounts of herbs give lower supply of larval host plants, which result in declining populations of day-living butterflies was strengthened by this study.</p>

Many of Europe’s day-living butterflies have shown decreasing populations during the last decades and many species are threatened. Many butterflies are dependent on managed semi-natural grasslands because of their richness in nectar sources and host plants for the butterfly larva. Swedish pastures are mostly managed through grazing. The number of cattle in Sweden have been decreasing while the number of sheep in the country increased by 30%. I examined if there was any differences in the butterfly and herb species diversity between pastures grazed by cattle or sheep. During the fieldwork, ten structurally similar pastures in the vicinity of Linköping, Östergötland were studied. Grazing by cattle was favourable both for butterfly and herb species with respect to species richness. Larger amounts of grass biomass and ground coverage by grass were in this study linked to sheep grazing. There have earlier been proposed that sheep graze more selective on herbs in favour of grass, with decreasing amounts of herbs and increasing amounts of grass in sheep grazed pastures, as a result. This theory is confirmed in this paper. The hypothesis that lower amounts of herbs give lower supply of larval host plants, which result in declining populations of day-living butterflies was strengthened by this study.

Die Novelle, Im Krebsgang, von Günter Grass ist eine Mischung aus Zeitgeschichte, persönlicher Biografie des Autors und lebhafter Fantasie. Diese Komponenten auseinanderzuhalten könnte die Verständigung der Novelle verbessern. Nach den Annahmen, dass der engste Personenkreis um die Familie Pokriefke Fiktion ist, und die Geschichten um den U-Boot-Kommandanten Marinesko, den Medizinstudenten Frankfurter, den Nationalsozialisten Gustloff und das KdF-Schiff Wilhelm Gustloff faktual sind, wurden sechs Textabschnitte ausgewählt. Durch eine literaturwissenschaftliche Analyse dieser Textabschnitte wurden sechs Punkte gefunden, die die Trennlinie zwischen den fiktionalen und faktualen Textabschnitten identifizieren. Gefunden wurde, dass in den faktualen Texten der Erzähler immer auktorial, aus großer Distanz berichtet, und immer von der Fokalisierung getrennt ist. In den fiktionalen Texten aber liegt immer die Fokalisierung beim Erzähler, der stets szenisch erzählt.

Nuisance aquatic vegetation (mainly Hydrilla Verticillata ) has become problematic in Lake Conroe, TX. Consequently, triploid grass carp (Ctenopharynogodon idella) were stocked at densities sufficient to completely denude the reservoir of all vegetation (invasive and native plants) within one year. As a result, an assessment was designed to investigate the changes (before and after carp stocking) in the plant assemblage among sampling stations, changes in water quality parameters, length frequency and condition changes of Centrachid species, largemouth diet changes, and changes in the fish assemblages among randomly selected sampling stations between early fall 2007, when grass carp were stocked, and one year later in early fall of 2008. The areas for sampling were based upon aquatic vegetation surveys by Texas Parks and Wildlife during 2007 and 2008, thirteen sampling stations were randomly selected using ArcGIS software and the percentage of water surface covered by vegetation was recorded at each station. Within each station, fish were collected by electrofishing the entire station for five minutes; water samples were also collected. Largemouth bass diet did significantly change for mature (<200 mm-TL) bass as indicated by a chi-square test. Largemouth bass from the samples were shown to consume less sunfish and more shad by the second (post-carp) sample. This is consistent with expected results due to the removal of vegetation consequently eliminating small sunfish habitat. In similar fashion, significant length-frequency changes were seen in the second year as there were fewer smaller (juvenile) Centrachid species found in the sampling sites. Contrary to the Centrachids, length-frequency of gizzard shad significantly decreased in size by the second sampling year. Based upon the aquatic vegetation surveys within the sampling sites of 2007 and 2008, there was an almost complete elimination of all aquatic plants following carp introduction. This result was consistent with what was expected from the carp introductions. Changes in water quality parameters (phosphorous, nitrate, nitrites, orthophosphate, chlorophyll (a)), were generally inconclusive, with the exception of nitrate which significantly increased by the second year. The water quality parameters along with other measured habitat parameters were used in the multivariate analysis.

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This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.