Agri-Food Globalisation and Rural Transformation in Chile: Smallholder Livelihoods in the Global Value Chain for Raspberries

As transnational capital continues to penetrate the agricultural sectors of developing countries, agri-food production-consumption is increasingly organised at the global scale. This has profound implications for small-scale farmers in the global South, who are being integrated into a globalising agri-food system geared towards the provision of agricultural commodities to meet the demands of wealthy consumers in Northern markets. Chile is one country that has purposefully inserted itself into the world trading system as an agri-exporter - a strategy that has fundamentally transformed Chilean agriculture. Framed within an examination of agrarian transformations in Chile and a world-historical account of agri-food globalisation, this thesis critically examines local-global linkages engendered by agri-food globalisation through a case study of export-oriented Chilean smallholder raspberry growers. The study aims to understand the structure and dynamics of the global value chain for raspberries, and to determine the livelihood implications of smallholder growers' participation in it. A detailed, locality case study was conducted in Yerbas Buenas - an important site of raspberry production within Chile - combining analysis of the raspberry value chain, and an in-depth survey of grower livelihoods. The value chain component focuses on key chain actors and functions within Chile, examining the role of public and private sector organisations governing and coordinating activities along the chain. The livelihoods component examines the significance of raspberry production within diversified household livelihood strategies, considering key assets, capabilities and mediating factors shaping smallholders' access to the value chain. Additionally, the research seeks to explore synergies and tensions between global value chain and sustainable rural livelihoods approaches, and to consider their integrative potential. The thesis finds that increasing competitive pressures, particularly arising from the evolving quality requirements of key overseas buyers, are seriously undermining the capacity of smallholder growers to participate in the chain. While existing private and public sector support is necessary for the participation of the smallest growers, it is not sufficient to secure their survival. It is argued that the neoliberal macroeconomic model represents a major barrier to smallholder participation, as the modernising agri-export-led growth strategy that it underpins can not accommodate the degree of intervention or the redistribution of resources required to address socio-economic inequality in the Chilean countryside

A global characterization of the translational and transcriptional programs induced by methionine restriction through ribosome profiling and RNA-seq

Background: Among twenty amino acids, methionine has a special role as it is coded by the translation initiation codon and methionyl-tRNAi (Met-tRNAi) is required for the assembly of the translation initiation complex. Thus methionine may play a special role in global gene regulation. Methionine has also been known to play important roles in cell growth, development, cancer, and aging. In this work, we characterize the translational and transcriptional programs induced by methionine restriction (MetR) and investigate the potential mechanisms through which methionine regulates gene expression, using the budding yeast S. cerevisiae as the model organism. Results: Using ribosomal profiling and RNA-seq, we observed a broad spectrum of gene expression changes in response to MetR and identified hundreds of genes whose transcript level and/or translational efficiency changed significantly. These genes show clear functional themes, suggesting that cell slows down its growth and cell cycle progression and increases its stress resistance and maintenance in response to MetR. Interestingly, under MetR cell also decreases glycolysis and increases respiration, and increased respiration was linked to lifespan extension caused by caloric restriction. Analysis of genes whose translational efficiency changed significantly under MetR revealed different modes of translational regulation: 1) Ribosome loading patterns in the 5'UTR and coding regions of genes with increased translational efficiency suggested mechanisms both similar and different from that for the translational regulation of Gcn4 under general amino acid starvation condition; 2) Genes with decreased translational efficiency showed strong enrichment of lysine, glutamine, and glutamate codons, supporting the model that methionine can regulate translation by controlling tRNA thiolation. Conclusions: MetR induced a broad spectrum of gene expression changes at both the transcriptional and translational levels, with clear functional themes indicative of the physiological state of the cell under MetR. Different modes of translational regulation were induced by MetR, including the regulation of the ribosome loading at 5'UTR and regulation by tRNA thiolation. Since MetR extends the lifespan of many species, the list of genes we identified in this study can be good candidates for studying the mechanisms of lifespan extension.National Institutes of Health [AG043080]SCI(E)ARTICLE1

S -Adenosyl- l -homocysteine in brain

Administration of methionine sulfoximine (MSO) to rats and mice significantly decreased cerebral levels of S -adenosyl- l -homocysteine (AdoHcy). Concurrent administration of methionine prevented this decrease and, when methionine was given alone, significantly elevated AdoHcy levels resulted in both species. Regionally, AdoHcy levels varied from 20 nmol/g in rat cerebellum and spinal cord to about 60 nmol/g in hypothalamus and midbrain. MSO decreased AdoHcy in all regions tested except striatum, midbrain, and spinal cord. AdoMet/AdoHcy ratios (methylation index) varied from 0.48 in hypothalamus to 2.4 in cerebellum, and MSO administration decreased these ratios in all regions except hypothalamus. AdoHcy hydrolase activity was lowest in hypothalamus, highest in brainstem and, generally, varied inversely with regional AdoHcy levels. MSO decreased AdoHcy hydrolase activity in all regions except hypothalamus and spinal cord. Cycloleucine administration resulted in significantly decreased levels of mouse brain AdoHcy, whereas the administration of dihydroxyphenylalanine (DOPA) failed to affect AdoHcy levels. It is concluded that (a) cerebral AdoHcy levels are more tightly regulated than are those of AdoMet after MSO administration, (b) slight fluctuations of AdoHcy levels may be important in regulating AdoHcy hydrolase activity and hence AdoHcy catabolism in vivo, (c) the AdoMet/AdoHcy ratio reflects the absolute AdoMet concentration rather than the transmethylation flux, (d) the decreased AdoMet levels in midbrain, cortex, and striatum after MSO with no corresponding decrease in AdoHcy suggest an enhanced AdoMet utilization, hence an increased transmethylation in the MSO preconvulsant state.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45411/1/11064_2004_Article_BF00966019.pd