The changing face of science communication, technology, extension and improved decision-making at the farm-water quality interface.

In recent decades, significant advances have been made in understanding the generation, fates and consequences of water quality pollutants in the Great Barrier Reef ecosystem. However, skepticism and lack of trust in water quality science by farming stakeholders has emerged as a significant challenge. The ongoing failures of both compulsory and particularly voluntary practices to improve land management and reduce diffuse agricultural pollution from the Great Barrier Reef catchment underlines the need for more effective communication of water quality issues at appropriate decision-making scales to landholders. Using recent Great Barrier Reef catchment experiences as examples, we highlight several emerging themes and opportunities in using technology to better communicate land use-water quality impacts and delivery of actionable knowledge to farmers, specifically supporting decision-making, behavior change, and the spatial identification of nutrient generation 'hotspots' in intensive agriculture catchments. We also make recommendations for co-designed monitoring-extension platforms involving farmers, governments, researchers, and related agencies, to cut across stakeholder skepticism, and achieve desired water quality and ecosystem outcomes.

Grasping at digitalisation: turning imagination into fact in the sugarcane farming community.

Nutrient runoff from catchments that drain into the Great Barrier Reef (GBR) is a significant source of stress for this World Heritage Area. An alliance of collaborative on-ground water quality monitoring (Project 25) and technologically driven digital application development (Digiscape GBR) projects were formulated to provide data that highlighted the contribution of a network of Australian sugar cane farmers, amongst other sources, to nutrient runoff. This environmental data and subsequent information were extended to the farming community through scientist-led feedback sessions and the development of specialised digital technology (1622™WQ) that help build an understanding of the nutrient movements, in this case nitrogen, such that farmers might think about and eventually act to alter their fertilizer application practices. This paper reflects on a socio-environmental sustainability challenge that emerged during this case study, by utilising the nascent concept of digi-grasping. We highlight the importance of the entire agricultural knowledge and advice network being part of an innovation journey to increase the utility of digital agricultural technologies developed to increase overall sustainability. We develop the digi-MAST analytical framework, which explores modes of being and doing in the digital world, ranging from 'the everyday mystery of the digital world (M)', through digital 'awareness (A)', digitally 'sparked' being/s (S), and finally the ability of individuals and/or groups to 'transform (T)' utilising digital technologies and human imaginations. Our digi-MAST framework allows us to compare agricultural actors, in this case, to understand present modes of digi-grasping to help determine the resources and actions likely to be required to achieve impact from the development of various forms of digital technological research outputs.

Isoform-specific interactions of human apolipoprotein E to an intermediate conformation of human Alzheimer amyloid-beta peptide.

Brain plaque deposits of amyloid-beta peptide (Abeta) is a pathological hallmark of Alzheimer's disease (AD) and apolipoprotein E (apoE) is thought to be involved in its deposition. One hypothesis for the role of apoE in the pathogenesis of AD is that apoE may be involved in deposition or clearance of Abeta by direct protein-to-protein interaction. Lipidated apoE4 bound preferentially to an intermediate aggregated form of Abeta and formed two- to three-fold more binding complexes than isoforms apoE2 or apoE3. The interaction was detected by a sandwich ELISA with capture antibodies specific for the N-terminus of apoE, whereas the interaction was not recognized with a C-terminal antibody. The observations indicate that the C-terminus of apoE4 interacts with the intermediate form of Abeta. The differential risk of AD related to apoE genotype may be the result of an enhanced capacity of apoE4 binding to an intermediate aggregated form of Abeta.

A slowly formed transient conformer of Abeta(1-40) is toxic to inward channels of dissociated hippocampal and cortical neurons of rats.

The mechanism by which amyloid peptide (Abeta(1-40)) produces effects on neurotransmission is currently unresolved. In initial experiments, using the patch-clamp technique, we found that 11.5 microM of preaggregated Abeta(1-40) altered the hippocampal neuron resting membrane potential and inhibited action potential firing. To identify the toxic species, the effects of Abeta(1-40) on sodium (I(Na)), calcium (I(Ca)), and potassium (I(K)) currents in hippocampal neurons were examined as a function of peptide aggregation state in a specially designed miniature recording chamber. Aggregation reactions were induced by constant shaking, starting with 50 microM monomeric peptide. At 10- to 30-min intervals, the ionic currents were examined on a single neuron suspended in control saline and then in a 100-microl sample of the aggregating peptide. We found that samples of the peptide taken 60-120 min into the aggregation process contained species that exhibited maximal inhibitory effects over a broad potential range in the rank ordering of I(Na) > I(Ca). I(K) was inhibited only slightly at depolarized potentials. Inhibition of APF through blockade of these channels would inhibit normal neuronal activity and directly contribute to cognitive dysfunction. In previous studies on SH-EP cells, we showed that neither monomeric nor fibrillar peptide had significant effect on cell viability except during exposure to the 60-120 minute aggregation product when cell death was recorded. Our kinetic model demonstrated that the toxic species was a slowly formed transient conformer (activated monomer), which was the only aggregating species that passed through a maximum concentration during aggregation. This species amounted to only a small fraction of the total amount of aggregating peptide. We conclude that, for both the native neurons in the present study as well as SH-EP1 cells, the activated monomeric conformer of the peptide is the toxic species.

Spontaneous aggregation and cytotoxicity of the beta-amyloid Abeta1-40: a kinetic model.

The time dependency of the spontaneous aggregation of the fibrillogenic beta-amyloid peptide, Abeta1-40, was measured by turbidity, circular dichroism, HPLC, and fluorescence polarization. The results by all methods were comparable and they were most consistent with a kinetic model where the peptide first slowly forms an activated monomeric derivative (AM), which is the only species able to initiate, by tetramerization, the formation of linear aggregates. The anti-Abeta antibody 6E10, raised against residues 1-17, at concentrations of 200-300 nM delayed significantly the aggregation of 50 microM amyloid peptide. The anti-Abeta antibody 4G8, raised against residues 17-24, was much less active in that respect, while the antibody A162, raised against the C-terminal residues 39-43 of the full-length Abeta was totally inactive at those concentrations. Concomitant with the aggregation experiments, we also measured the time dependency of the Abeta1-40-induced toxicity toward SH-EPI cells and hippocampal neurons, evaluated by SYTOX Green fluorescence, lactate dehydrogenase release, and activation of caspases. The extent of cell damage measured by all methods reached a maximum at the same time and this maximum coincided with that of the concentration of AM. According to the kinetic scheme, the latter is the only transient peptide species whose concentration passes through a maximum. Thus, it appears that the toxic species of Abeta1-40 is most likely the same transient activated monomer that is responsible for the nucleation of fibril formation. These conclusions should provide a structural basis for understanding the toxicity of Abeta1-40 in vitro and possibly in vivo.