Symposium introduction - ethics and sustainable agri-food governance: appraisal and new directions

© Springer Nature B.V. 2019This Symposium contributes to a theoretical and methodological discussion on the role of ethics and responsibility in the governance of agri-food systems, as drivers for transitions towards sustainability. The papers in the Symposium are the outcomes of a collective reflection that was initiated at the European Society for Rural Sociology (ESRS) 2017 congress, within the Working Group on Ethics and sustainable agri-food governance. The session examined how ethics and ethical values drive change in the agri-food system, and how they increasingly evolve and influence food system governance. Building on the outcomes of the ESRS Working Group, the collection of papers in this Symposium fosters and deepens the discussion on the role of ethics in food systems, ranging across different food system actors, activities and contexts and presents new theoretical and methodological frameworks to understand the construction of more ethical agri-food systems.Peer reviewedFinal Accepted Versio

Carbon monoxide binding to iron porphyrins

The carbon monoxide affinities of iron complexes of meso-tetra (α,α,α,α-o-pivalamidophenyl)porphyrin (the "picket fence" porphyrin) and of a "picket fence" porphyrin derivative with an appended axial base have been measured in solution and compared with the CO affinities of various hemoproteins. The model complexes bind CO with much greater affinity than normal hemoproteins; the role of the steric bulk of distal residues in lowering the CO affinities of the hemoproteins is discussed. The significance of this lowered CO affinity is described with regard to endogenous CO. A discussion of mutant hemoglobins lacking distal residues that sterically inhibit the binding of CO is presented. The use of pressure units versus concentration units in equilibrium expressions is analyzed

Proximal and distal control for ligand binding in neuroglobin: role of the CD loop and evidence for His64 gating

Neuroglobin (Ngb) is predominantly expressed in neurons of the central and peripheral nervous systems and it clearly seems to be involved in neuroprotection. Engineering Ngb to observe structural and dynamic alterations associated with perturbation in ligand binding might reveal important structural determinants, and could shed light on key features related to its mechanism of action. Our results highlight the relevance of the CD loop and of Phe106 as distal and proximal controls involved in ligand binding in murine neuroglobin. We observed the effects of individual and combined mutations of the CD loop and Phe106 that conferred to Ngb higher CO binding velocities, which we correlate with the following structural observations: the mutant F106A shows, upon CO binding, a reduced heme sliding hindrance, with the heme present in a peculiar double conformation, whereas in the CD loop mutant "Gly-loop", the original network of interactions between the loop and the heme was abolished, enhancing binding via facilitated gating out of the distal His64. Finally, the double mutant, combining both mutations, showed a synergistic effect on CO binding rates. Resonance Raman spectroscopy and MD simulations support our findings on structural dynamics and heme interactions in wild type and mutated Ngbs

Allosteric Activation of the Par-6 PDZ Via a Partial Unfolding Transition

Proteins exist in a delicate balance between the native and unfolded states, where thermodynamic stability may be sacrificed to attain the flexibility required for efficient catalysis, binding, or allosteric control. Partition-defective 6 (Par-6) regulates the Par polarity complex by transmitting a GTPase signal through the Cdc42/Rac interaction binding PSD-95/Dlg/ZO-1 (CRIB-PDZ) module that alters PDZ ligand binding. Allosteric activation of the PDZ is achieved by local rearrangement of the L164 and K165 side chains to stabilize the interdomain CRIB:PDZ interface and reposition a conserved element of the ligand binding pocket. However, microsecond to millisecond dynamics measurements revealed that L164/K165 exchange requires a larger rearrangement than expected. The margin of thermodynamic stability for the PDZ domain is modest (∼3 kcal/mol) and further reduced by transient interactions with the disordered CRIB domain. Measurements of local structural stability revealed that tertiary contacts within the PDZ are disrupted by a partial unfolding transition that enables interconversion of the L/K switch. The unexpected participation of partial PDZ unfolding in the allosteric mechanism of Par-6 suggests that native-state unfolding may be essential for the function of other marginally stable proteins

Creating value(s) by integrating local and extra-local resources in cereal production in the Swiss Alps

This paper explores the long-term prospect of alternative, local food initiatives, taking a particular interest in the development of the embedded local values, understood as economic as well as cultural values. Analysing the case of a cooperative of mountain cereal farmers in Switzerland, we show that sustaining local values-based quality is a dynamic process of linking local and extra-local resources. Our results first show the importance of both proximity and place in constructing the ‘local’ by the cooperative. Second, product flow, knowledge and information exchange, quality control, and innovation are governed by both horizontal and vertical relationships between local and extra-local resources, and these multiple relationships build trust in the network and beyond. This, thirdly, enables the cooperative to continuously reproduce its values by weaving them into a cycle of quality creation. We conclude that we need to understand the characteristic values-based quality of the cooperative’s products as the result of a recurring cycle of local and extra-local knowledge creation and resource exchange

Oxidation of Native and Modified Hemoglobin and Myoglobin by Sodium Nitrate. Effect of Inositol Hexaphosphate

Native and modified hemoglobin, myoglobin and a and phemoglobin subunits were oxidized by sodium nitrite at pH 6. The experiments were carried out under oxy and deoxy conditions with and without inositol hexaphosphate (IHP). It is shown (a) that under oxy condition low concentration of IHP inhibits the oxidation of native hemoglobin only. However, high concentration of IHP inhibits the oxidation of both myoglobin and modified hemoglobin (digested or 0-93-SH groups blocked). This inhibition is partially counteracted by high oxygen pressure, (b) Under deoxy condition the oxidation rates of all hemeproteins studied are significantly faster than that of native hemoglobin. IHP inhibits the oxidation of all except the myoglobin and hemoglobin subunits. It is concluded that although the IHP inhibitory effect on hemoglobin oxidation by nitrite can be explained by the shift of the R↔T conformational equilibrium towards T conformation, some other structural changes such as alteration in molecular surface charges must occur to account for the effect of IHP on the oxidation of hemeproteins devoid of heme-heme interaction

Unveiling the folding mechanism of the bromodomains

Bromodomains (BRDs) are small protein domains often present in large multidomain proteins involved in transcriptional regulation in eukaryotic cells. They currently represent valuable targets for the development of inhibitors of aberrant transcriptional processes in a variety of human diseases. Here we report urea-induced equilibrium unfolding experiments monitored by circular dichroism (CD) and fluorescence on two structurally similar BRDs: BRD2(2) and BRD4(1), showing that BRD4(1) is more stable than BRD2(2). Moreover, we report a description of their kinetic folding mechanism, as obtained by careful analysis of stopped-flow and temperature-jump data. The presence of a high energy intermediate for both proteins, suggested by the non-linear dependence of the folding rate on denaturant concentration in the millisec time regime, has been experimentally observed by temperature-jump experiments. Quantitative global analysis of all the rate constants obtained over a wide range of urea concentrations, allowed us to propose a common, three-state, folding mechanism for these two BRDs. Interestingly, the intermediate of BRD4(1) appears to be more stable and structurally native-like than that populated by BRD2(2). Our results underscore the role played by structural topology and sequence in determining and tuning the folding mechanism

Opportunities and Barriers for Niche Marketing of Lamb in European LFAs based on Consumer Attitudes to Product Quality

With commodity prices continuing to decrease and with policy constraint that farmers cannot easily increase their incomes by increasing volumes of production, they must find alternative ways to maintain their standard of living. This can be achieved by either niche marketing of agricultural products or by environmental payments, which are either paid by the government or the consumer. The results of a consumer survey carried out in Less Favoured Areas in Scotland, Germany, Greece, France and Italy to assess consumer attitudes of what constitutes the quality of lamb and the extent to which this provides an opportunity to exploit niche marketing, are discussed. Consumers generally have much less interest in the use of regional labelling, ecologically friendly production systems or the linkage of landscape and production systems in the buying decision. It is concluded that potential exists to develop niche markets for lamb and that these niches demonstrate significant regional differences. Equally, however, it is concluded that there are only limited rewards for production systems which are sympathetic to the environment. To achieve this goal, policy intervention is required, geared directly to environmental management practices. Future policy support towards farmers in LFAs is needed as a mix of policy instrument. Nowadays, financial support of farming in LFAs is necessary to grant farmers income, but structural support (e. g. in marketing products under reliable labelling towards consumers’ requests with trust in the "added values") can help to increase LFA-farmers income without increasing subsidies

Old institutions, new challenges: the agricultural knowledge system in Hungary

This paper explores and analyses the Hungarian institutional system for the creation and the transfer of knowledge in the fi eld of agriculture and rural development. We consider the constitution and operation of the Agricultural Knowledge System (AKS) in Hungary, focussing on the formally organised aspects, and suggest that both the structure and content of the knowledge needed in the sector have signifi cantly changed during the past decades. These changes, especially in relation to the sustainability of agriculture, pose signifi cant challenges to traditional AKS institutions, which often have failed to change in line with the new requirements. Based on a literature review, interviews and a national stakeholder workshop, we offer an analysis of Hungarian AKS institutions, their co-ordination, co-operation and communication with each other and with Hungarian rurality, and of the arising issues and problems concerning the creation and the fl ow of knowledge needed for sustainable agriculture. We also briefl y explore characteristics of emerging bottom-up structures, called LINSAS (learning and innovation networks for sustainable agriculture), and explore the signifi cance of the fi ndings in this article for the study of AKS in Europe. This article is based on preliminary results of the SOLINSA research project, supported by the European Union’s Seventh Framework Programme

The role of a disulfide bridge in the stability and folding kinetics of Arabidopsis thaliana cytochrome c6A

Cytochrome c 6A is a eukaryotic member of the Class I cytochrome c family possessing a high structural homology with photosynthetic cytochrome c 6 from cyanobacteria, but structurally and functionally distinct through the presence of a disulfide bond and a heme mid-point redox potential of + 71 mV (vs normal hydrogen electrode). The disulfide bond is part of a loop insertion peptide that forms a cap-like structure on top of the core α-helical fold. We have investigated the contribution of the disulfide bond to thermodynamic stability and (un)folding kinetics in cytochrome c 6A from Arabidopsis thaliana by making comparison with a photosynthetic cytochrome c 6 from Phormidium laminosum and through a mutant in which the Cys residues have been replaced with Ser residues (C67/73S). We find that the disulfide bond makes a significant contribution to overall stability in both the ferric and ferrous heme states. Both cytochromes c 6A and c 6 fold rapidly at neutral pH through an on-pathway intermediate. The unfolding rate for the C67/73S variant is significantly increased indicating that the formation of this region occurs late in the folding pathway. We conclude that the disulfide bridge in cytochrome c 6A acts as a conformational restraint in both the folding intermediate and native state of the protein and that it likely serves a structural rather than a previously proposed catalytic role. © 2011 Elsevier B.V. All rights reserved