'Deor and nytenu mid us': animals in the works of Ǽelfric

This dissertation examines the use of animals in Ælfric’s Lives of Saints and Catholic Homilies, outlining the transmission process of various sources of animal knowledge available to and used by Ælfric. The contexts in which Ælfric uses animals, which sources he uses in these passages and how he deviates from his source material (if at all) combine to illustrate how Anglo-Saxon authors could weave classical, biblical, early Christian and local knowledge together and incorporate the different traditions in their own work.

The use of different blood sample preparations in the development of biomarkers for the environmental monitoring of domestic farm animals

The application of biological effect monitoring for the detection of environmental chemical exposure in domestic animals is still in its infancy. This study investigated blood sample preparations in vitro for their use in biological effect monitoring. When peripheral blood mononuclear cells (PBMCs), isolated following the collection of multiple blood samples from sheep in the field, were cryopreserved and subsequently cultured for 24 hours a reduction in cell viability (<80%) was attributed to delays in the processing following collection. Alternative blood sample preparations using rat and sheep blood demonstrated that 3 to 5 hour incubations can be undertaken without significant alterations in the viability of the lymphocytes; however, a substantial reduction in viability was observed after 24 hours in frozen blood. Detectable levels of early and late apoptosis as well as increased levels of ROS were detectable in frozen sheep blood samples. The addition of ascorbic acid partly reversed this effect and reduced the loss in cell viability. The response of the rat and sheep blood sample preparations to genotoxic compounds ex vivo showed that EMS caused comparable dose-dependent genotoxic effects in all sample preparations (fresh and frozen) as detected by the Comet assay. In contrast, the effects of CdCl2 were dependent on the duration of exposure as well as the sample preparation. The analysis of leukocyte subsets in frozen sheep blood showed no alterations in the percentages of T and B lymphocytes but led to a major decrease in the percentage of granulocytes compared to those in the fresh samples. The percentages of IFN-γ and IL-4 but not IL-6 positive cells were comparable between fresh and frozen sheep blood after 4 hour stimulation with phorbol 12-myrisate 13-acetate and ionomycin (PMA+I). These results show that frozen blood gives comparable responses to fresh blood samples in the toxicological and immune assays used.

Growing up in a bubble: using germ-free animals to assess the influence of the gut microbiota on brain and behavior

There is a growing recognition of the importance of the commensal intestinal microbiota in the development and later function of the central nervous system. Research using germ-free mice (mice raised without any exposure to microorganisms) has provided some of the most persuasive evidence for a role of these bacteria in gut-brain signalling. Key findings show that the microbiota is necessary for normal stress responsivity, anxiety-like behaviors, sociability, and cognition. Furthermore, the microbiota maintains central nervous system homeostasis by regulating immune function and blood brain barrier integrity. Studies have also found that the gut microbiota influences neurotransmitter, synaptic, and neurotrophic signalling systems and neurogenesis. The principle advantage of the germ-free mouse model is in proof-of-principle studies and that a complete microbiota or defined consortiums of bacteria can be introduced at various developmental time points. However, a germ-free upbringing can induce permanent neurodevelopmental deficits that may deem the model unsuitable for specific scientific queries that do not involve early-life microbial deficiency. As such, alternatives and complementary strategies to the germ-free model are warranted and include antibiotic treatment to create microbiota-deficient animals at distinct time points across the lifespan. Increasing our understanding of the impact of the gut microbiota on brain and behavior has the potential to inform novel management strategies for stress-related gastrointestinal and neuropsychiatric disorders.