Urbanization is widely presumed to degrade ecosystem services, but empirical evidence is now challenging these assumptions. We report the first city-wide organic carbon (OC) budget for vegetation and soils, including under impervious surfaces. Urban soil OC storage was significantly greater than in regional agricultural land at equivalent soil depths, however there was no significant difference in storage between soils sampled beneath urban greenspaces and impervious surfaces, at equivalent depths. For a typical U.K. city, total OC storage was 17.6 kg m−2 across the entire urban area (assuming 0 kg m−2 under 15% of land covered by buildings). The majority of OC (82%) was held in soils, with 13% found under impervious surfaces, and 18% stored in vegetation. We reveal that assumptions underpinning current national estimates of ecosystem OC stocks, as required by Kyoto Protocol signatories, are not robust and are likely to have seriously underestimated the contributions of urban areas.

Recently we cloned and described ERp29, a novel 29-kDa endoplasmic reticulum (ER) protein that is widely expressed in rat tissues. Here we report our original isolation of ERp29 from dental enamel cells, and the comprehensive sequence analysis that correlated ERp29 with its cognate cDNA, both in enamel cells and liver. Fractionation of enamel cells using a new freeze±thaw procedure showed that ERp29 partitioned with known reticuloplasmins, and not with soluble proteins from mitochondria or cytosol. The absence of ERp29 in secreted enamel matrix indicated that the C-terminal tetrapeptide (KEEL motif ) confers effective ER-retention in enamel cells. ERp29 behaved as a single species (< 40 kDa) during size-exclusion chromatography of liver reticuloplasm, suggesting that most ERp29 is not stably associated with other proteins. Immunoblot analysis showed that ERp29 was up-regulated during enamel secretion and expressed most highly in secretory tissues, indicative of a role in secretory-protein synthesis. Unlike other reticuloplasmins, ERp29 was down-regulated during enamel mineralization and thereby dissociated from a calcium-handling role. Tissue-specific variations in ERp29 molecular abundance were revealed by quantification of reticuloplasmin mole ratios. In conclusion: (a) ERp29 is a novel reticuloplasmin of general functional importance; (b) a unique role in protein processing is implicit from the distinctive expression patterns and molecular structure; (c) ERp29 is primarily involved in normal protein secretory events, not the ER stress response; (d) a major role is likely in tissues where ERp29 was equimolar with established molecular chaperones and foldases. This study implicates ERp29 as a new member of the ER protein-processing machinery, and identifies tissues where the physiological role of ERp29 is most likely to be clearly manifested.

Mitochondrial ATP synthase is responsive to changes in cytosolic calcium concentration, but the regulatory mechanisms are unclear. Here we identified a major 52 kDa calciumbinding protein in rat enamel cells as the mitochondrial ATP synthase Fl-~subunit. The Fl-~-subunit behaved as a low affinity and moderate capacity calcium-binding protein during comparative 45Ca overlay analyses. Equivalent behavior was shown by the Fl-[I-subunit from rat liver mitochondria, but not by the homologous Fl-a-subunit, supporting the specificity of calcium binding. Evidence that the catalytic Fr~-subuuit binds calcium specifically introduces new mechanistic possibilities for regulating ATP synthase, and thereby coordinating ATP production with demand for ATP-fuelled calcium pump activity.

ood insecurity is a growing issue in the Global North 1,2 , where the majority of the population (sometimes in excess of 80%) lives in urban areas 3. Food production in urban areas, particularly horticultural production 4,5 , is increasingly recognized at all levels of governance, from local to transnational, as an important contributor to food security 6. Despite this recognition, there have been few attempts to analyse the feasibility of urban horticulture (UH) in terms of the space available within the urban fabric. We explore this issue in a case study city in the United Kingdom using a geographic information system (GIS) to map green infrastructure now used for UH along with other green infrastructure (such as parks, gardens, roadside verges and woodland) and grey infrastructure (buildings, for example) that has the potential to form part of an expanding UH system. We then develop a conceptual framework that addresses the scientific, practical engineering, knowledge, economic and socio-cultural factors that underpin sustainable UH delivery in the Global North. Within this framework, we consider two different forms of UH: soil-based horticulture (SBH) within green infrastructure and controlled environment horticulture (CEH) on flat roofs within grey infrastructure.

Recently we characterised a novel 29 kDa endoplasmic reticulum protein that is widely expressed in rat tissues, and named it ERp29. Several ERp29-like gene products have been reported in human tissues but uncertainty surrounds their relationships with each other and rat ERp29. To clarify these issues, ERp29 was isolated from human liver and characterised by primary structural analysis and two-dimensional gel mapping. Comparisons with rat ERp29 revealed striking homologies both in sequence and physical properties. Characterisation of the isoelectric heterogeneity and anomalous mass on two-dimensional gels enabled two reported homologues (UL35 and ERp31) to be identified as ERp29. Resolution of a sequence discrepancy led to unequivocal correlation of human ERp29 with the cognate cDNA previously named ERp31 and ERp28. Consequent links established to human genome and proteome projects showed that ERp29 is encoded by a gene on chromosome 12 that is expressed universally in human tissues. Together, these findings unified various ERp29 homologues as products of a single gene orthologous to rat ERp29 and established ERp29 as the only known member of a new protein class. Investigations of ERp29 function in human health and disease should benefit from the integrated links between genome, proteome and murine model organisms established here.