Causes of mortality and characterisation of Mycobacteriosis in adult New Zealand sea lions (Phocarctos Hookeri) at Enderby Island : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science in Wildlife Health at Massey University, Manawatū, Palmerston North, New Zealand

The New Zealand sea lion (Phocarctos hookeri) is classified as endangered and “Nationally Critical” due to a declining population and restricted population range. There have been recent bacterial epizootic events at the breeding colonies of this species, however the role of disease in the population decline is not known. As part of the investigation into the population decline, the species management plan recommends investigation of disease agents affecting this species, their epidemiology and their long-term effects on population dynamics. Since the 1998/1999 breeding season, post mortem examinations have been performed on deceased New Zealand sea lions at the Enderby Island breeding colonies during each breeding season, including the collection of samples for histology and bacteriology. This study describes the causes of mortality in New Zealand sea lions one year of age and older at Enderby Island between the 1998/99 to 2010/11 breeding seasons inclusive, using the archived post mortem reports, histology samples and bacteriology samples. Conspecific trauma was found to be a significant cause of mortality (34.3%), as were various infectious causes (35.7%). The organism Klebsiella pneumoniae was isolated from non-pup New Zealand sea lions both from individuals that died from other causes and individuals that showed apparent morbidity as a result of this bacteria. These findings suggest that older animals may be reservoirs of infection for K. pneumoniae, which causes significant mortality in neonatal New Zealand sea lions. Another important infectious agent that was described in non-pup New Zealand sea lions was Mycobacterium pinnipedii, which caused both subclinical and clinical disease. Mycobacteriosis of the lymph nodes, lungs, pleura, liver, peritoneum and reproductive tract was described in this study. Strain determination of the M. pinnipedii isolates grown show only minor strain variation among isolates, which may reflect the isolated geographic distribution of these animals. There was no apparent association between the individual strains of M. pinnipedii and their pathogenicity as indicated by the pathology present in infected animals

GTA: Groupware task analysis Modeling complexity

The task analysis methods discussed in this presentation stem from Human-Computer Interaction (HCI) and Ethnography (as applied for the design of Computer Supported Cooperative Work CSCW), different disciplines that often are considered conflicting approaches when applied to the same design problems. Both approaches have their strength and weakness, and an integration of them does add value to the early stages of design of cooperation technology. In order to develop an integrated method for groupware task analysis (GTA) a conceptual framework is presented that allows a systematic perspective on complex work phenomena. The framework features a triple focus, considering (a) people, (b) work, and (c) the situation. Integrating various task-modeling approaches requires vehicles for making design information explicit, for which an object oriented formalism will be suggested. GTA consists of a method and framework that have been developed during practical design exercises. Examples from some of these cases will illustrate our approach

New enzyme based process direction to prevent wool shrinking without substantial tensile strength loss

In this paper a new enzymatic process direction is described for obtaining machine washable wool with acceptable quality. In general, application of protease enzyme technology in wool processing results in considerable loss of tensile strength by diffusion of the enzyme into the interior of wool fibers. To overcome this disadvantage enzymatic activity has been more targeted to the outer surface of the scales by improving the susceptibility of the outer surface scale protein for proteolytic degradation. This has been realized by a pretreatment of wool with hydrogen peroxide at alkaline pH in the presence of high concentrations of salt

Staphylococcus aureus protein A binding to von Willebrand factor A1 domain is mediated by conserved IgG binding regions.

Protein A (Spa) is a surface-associated protein of Staphylococcus aureus best known for its ability to bind to the Fc region of IgG. Spa also binds strongly to the Fab region of the immunoglobulins bearing V(H)3 heavy chains and to von Willebrand factor (vWF). Previous studies have suggested that the protein A-vWF interaction is important in S. aureus adherence to platelets under conditions of shear stress. We demonstrate that Spa expression is sufficient for adherence of bacteria to immobilized vWF under low fluid shear. The full length recombinant Ig-binding region of protein A, Spa-EDABC, fused to glutathione-S-transferase (GST), bound recombinant vWF in a dose-dependent and saturable fashion with half maximal binding of about 30 nm in immunosorbent assays. Full length-Spa did not bind recombinant vWF A3 domain but displayed binding to recombinant vWF domains A1 and D\u27-D3 (half maximal binding at 100 nm and 250 nm, respectively). Each recombinant protein A Ig-binding domain bound to the A1 domain in a similar manner to the full length-Spa molecule (half maximal binding 100 nm). Amino acid substitutions were introduced in the GST-SpaD protein at sites known to be involved in IgG Fc or in V(H)3 Fab binding. Mutants altered in residues that recognized IgG Fc but not those that recognized V(H)3 Fab had reduced binding to vWF A1 and D\u27-D3. This indicated that both vWF regions recognized a region on helices I and II that overlapped the IgG Fc binding site

Glass corrosion : Towards a Unifying Mechanistic Model

Borosilicate glasses are currently used for the immobilization of highly radioactive waste and are materials of choice for many biomedical and research industries. They are metastable materials that corrode in aqueous solutions, reflected by the formation of silica-rich corrosion rims. Until now, there is no consensus in the scientific community about the reaction and transport mechanism(s) and the rate-limiting steps involved in the corrosion of silicate glasses. Most models have the basic assumption in common that ion release from the glass network is occurring via interdiffusion and that the glass network itself is not being disrupted, only modified. On the contrary stands the interface-coupled dissolution-precipitation (ICDP) model, which first was developed for mineral replacement reactions and was recently adapted to glass corrosion. It is based on the congruent dissolution of the glass network that is spatially and temporally coupled to the precipitation and polymerization of silica, forming the amorphous corrosion rim. The dissolution of a radionuclide-binding glass matrix is naturally a sensitive issue for the safe disposal of vitrified high-level nuclear waste. A sound description of the reaction mechanisms and the identification of the rate-limiting steps is essential to predict the long-term corrosion of silicate glasses, particularly when time scales must reach several thousand to millions of years as required by safety regulations for a nuclear repository. In three project studies, the broad spectrum of borosilicate glass corrosion was investigated from the first surface precipitates at an inward-moving solution-glass interface, over the dynamic development of the corrosion rim itself, and the tracing of individual species within the corrosion rim and across the rim-glass interface. Results of atomic force microscopy and single-pass flow-through experiments deliver strong evidence for a significant compositional difference between the surfacial and bulk solution. Hence, local supersaturation of the interfacial solution with respect to amorphous silica at the glass surface can explain how precipitation of silica can occur when the bulk solution is still undersaturated. To study the dynamic development of the corrosion rim in space and time, a novel fluid cell-based in situ Raman spectroscopy method devised. This method allows monitoring the congruent dissolution of the glass and simultaneously the precipitation and polymerization of the silica-based corrosion rim at elevated temperatures in space and time without the need to terminate the running experiment. For the first time, the formation of a silica- and water-rich zone at the interface between glass and corrosion rim could be observed in operando. Commonly such zones were identified post mortem as gaps or cracks between pristine glass and corrosion rim, and, hence, referred to as result of sample drying. However, these results show that these discontinuities are a primary feature of the corrosion process itself and that the dissolution process must proceed within the therein present interfacial fluid. Lastly, multi-isotope tracer (2H, 18O, 10B, 30Si, 44Ca) experiments were performed on pristine and already corroded glass monoliths of different glass compositions. Results of transmission electron microscopy and analyses by nanoscale secondary ion mass spectrometry reveal a nanometre-sharp interface between the silica-based corrosion rim and the glass, where decoupling of isotope tracer occurs, while proton diffusion and ion exchange can be observed within the glass. Moreover, a dense layer was observed between the corrosion rim and glass, which appears to the quenched silica-rich interfacial (pore) solution, which was observed in operando in the in situ Raman experiment. As these new findings cannot be explained by solid-state diffusion processes, nor the classical ICDP process accounts for ion exchange in the glass, a unifying mechanistic model is proposed, which accounts for all critical observations so far made on naturally and experimentally corroded glasses. The main corrosion rim forming process is based on the interface-coupled glass dissolution-silica precipitation reaction. However, a diffusion front over several tens of nanometres may evolve in the glass ahead of the dissolution interface once transport limitations cause the dissolution rate to become slower than the diffusion rate of individual species (DH = 1.3 × 10-23 m2 s-1)

Emicizumab and thrombosis : the story so far

International audienc

Two microcrustaceans affect microbial and macroinvertebrate-driven litter breakdown

1. Leaf litter degradation in fresh waters is a fundamental ecosystem process performed by a wide array of decomposers. The meiofauna is an important component of aquatic heterotrophic assemblages, which can provide a trophic link between plant detritus and associated microbial and macroinvertebrate communities, but their contribution to leaf breakdown remains poorly understood. 2. We hypothesised that, through their feeding activity, microcrustaceans influence the structure of fungal assemblages and consequently microbially mediated litter breakdown. Litter-associated microcrustaceans were predicted to change the pathways of energy transfer in the food web according to the positive (e.g. complementarity) or negative (e.g. predation) interactions with macroinvertebrate detritivore taxa. 3. We evaluated experimentally in the laboratory, over 6 and 13 days, the potential contribution of two freshwater microcrustaceans (a cladoceran and a copepod) to litter breakdown in the presence of microfungi (aquatic hyphomycetes), with and without macroinvertebrate detritivores (a trichopteran and a gammarid amphipod). 4. The presence of microcrustaceans enhanced leaf mass loss by 62 and 22% in treatments with fungi or trichopteran alone, respectively, while no significant effect was observed for treatments with the amphipod. Microcrustaceans strongly increased the production of fine particulate organic matter, particularly in treatments with fungi alone (+637%). The leaf consumption rate by the amphipod significantly decreased ( 61%) at 13 days in the presence of microcrustaceans, likely due to predation on cladocerans. 5. Our study supports the potential role of microcrustaceans in the detrital food web of streams and rivers. Interestingly, microcrustaceans may interact with microbial and macroinvertebrate decomposers in either positive or negative ways. Therefore, microcrustaceans add complexity to detrital food webs by increasing vertical diversity and modulating biotic interactions with important consequences for carbon and energy transfers in stream ecosystems

Restricting detergent protease action to surface of protein fibres by chemical modification

Due to their excellent properties, such as thermostability, activity over a broad range of pH and efficient stain removal, proteases from Bacillus sp. are commonly used in the textile industry including industrial processes and laundry and represent one of the most important groups of enzymes. However, due to the action of proteases, severe damage on natural protein fibres such as silk and wool result after washing with detergents containing proteases. To include the benefits of proteases in a wool fibre friendly detergent formulation, the soluble polymer polyethylene glycol (PEG) was covalently attached to a protease from Bacillus licheniformis. In contrast to activation of PEG with cyanuric chloride (50%) activation with 1,1′-carbonyldiimidazole (CDI) lead to activity recovery above 90%. With these modified enzymes, hydrolytic attack on wool fibres could be successfully prevented up to 95% compared to the native enzymes. Colour difference (ΔE) measured in the three dimensional colour space showed good stain removal properties for the modified enzymes. Furthermore, half-life of the modified enzymes in buffers and commercial detergents solutions was nearly twice as high as those of the non-modified enzymes with values of up to 63 min. Out of the different modified proteases especially the B. licheniformis protease with the 2.0-kDa polymer attached both retained stain removal properties and did not hydrolyse/damage wool fibres