Do the poor pay more for food? To answer this question, this study was conducted to provide an empirical analysis of grocery store access and prices across inner city and suburban communities within the Minneapolis and St. Paul metropolitan area. The comparison among different types of grocers and geographic areas is drawn from a survey of approximately fifty grocery items for fifty-five stores. Results indicate that the poor pay only slightly more in the Twin Cities grocery market. Morz significantly, those who shop in non-chain stores pay a significant premium, and the poor have less access to chain stores. This study mveals that the biggest factor contributing to higher grocery costs in poor neighborhoods is that large chain stores, where prices tend to be lower, are not located in these neighborhoods.Consumer groups have frequently contended that residents in poor, inner-city communities are at a disadvantage in the prices, quality, and quantity of groceries sold in their communities. This contention raises fundamental questions about grocery store access and prices. Do types and sizes of grocery stores located in the innercity differ from suburban neighborhoods? Do different types of grocers charge different prices? Do prices differ depending on location? To examine these questions, this study provides an empirical analysis of grocery store access and prices across inner-city and suburban communities within the Twin Cities-metropolitan area. Like many other midsized metropolitan cities in United States, the inner-city poverty problem in the Twin Cities has become more significant over the past decades.' Across the country, various researchers, community-based organiza-Chanjin Chung is Research Associate,

Background: Increasing energy costs and environmental concerns have motivated engineering microbes for the production of "second generation" biofuels that have better properties than ethanol.

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Metabolic flux analysis via (13)C labeling ((13)C MFA) quantitatively tracks metabolic pathway activity and determines overall enzymatic function in cells. Three core techniques are necessary for (13)C MFA: (1) a steady state cell culture in a defined medium with labeled-carbon substrates; (2) precise measurements of the labeling pattern of targeted metabolites; and (3) evaluation of the data sets obtained from mass spectrometry measurements with a computer model to calculate the metabolic fluxes. In this review, we summarize recent advances in the (13)C-flux analysis technologies, including mini-bioreactor usage for tracer experiments, isotopomer analysis of metabolites via high resolution mass spectrometry (such as GC-MS, LC-MS, or FT-ICR), high performance and large-scale isotopomer modeling programs for flux analysis, and the integration of fluxomics with other functional genomics studies. It will be shown that there is a significant value for (13)C-based metabolic flux analysis in many biological research fields.

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1A recently discovered thermophilic bacterium, Geobacillus thermoglucosidasius 2 M10EXG, ferments a range of C5 (e.g., xylose) and C6 sugars (e.g., glucose) and is tolerant to 3 high ethanol concentrations (10% v/v). We have investigated the central metabolism of this 4 bacterium using both in vitro enzyme assays and 13 C-based flux analysis to provide insights into 5 the physiological properties of this extremophile and explore its metabolism for bioethanol or 6 other bioprocess applications. Our findings show that glucose metabolism in G. 7 thermoglucosidasius M10EXG proceeds via glycolysis, the pentose phosphate pathway, and the 8 TCA cycle; the Entner-Doudoroff pathway and transhydrogenase activity were not detected. 9Anaplerotic reactions (including the glyoxylate shunt, pyruvate carboxylase and 10 phosphoenolpyruvate carboxykinase) were active, but fluxes through those pathways could not 11 be accurately determined using amino acid labelling. When growth conditions were switched 12 from aerobic to micro-aerobic conditions, fluxes (based on a normalized glucose uptake rate of 13 100 units (gm DCW) -1 ·hr -1 ) through the TCA cycle and oxidative pentose phosphate pathway 14 were reduced from 64±3 to 25±2 and from 30±2 to 19±2, respectively. The carbon flux under 15 microaerobic growth was directed to ethanol, L-lactate (>99% optical purity), acetate, and 16formate. Under fully anaerobic conditions, G. thermoglucosidasius M10EXG used a mixed acid 17 fermentation process and exhibited a maximum ethanol yield of 0.38±0.07 mol mol -1 glucose. In 18 silico flux balance modelling demonstrates that lactate and acetate production from G. 19 thermoglucosidasius M10EXG reduces the maximum ethanol yield by approximately three 20 folds, thus indicating that both pathways should be modified to maximize ethanol production. 21

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