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Fagan Hildebrandt posted an update 1 day, 6 hours ago
© 2020 The American Geriatrics Society.Microbial production of mevalonate from renewable feedstock is a promising and sustainable approach for the production of value-added chemicals. We describe the metabolic engineering of Escherichia coli to enhance mevalonate production from glucose and cellobiose. First, the mevalonate-producing pathway was introduced into E. coli and the expression of the gene atoB, which encodes the gene for acetoacetyl-CoA synthetase, was increased. Then, the deletion of the pgi gene, which encodes phosphoglucose isomerase, increased the NADPH/NADP+ ratio in the cells but did not improve mevalonate production. Alternatively, to reduce flux toward the tricarboxylic acid cycle, gltA, which encodes citrate synthetase, was disrupted. The resultant strain, MGΔgltA-MV, increased levels of intracellular acetyl-CoA up to sevenfold higher than the wild-type strain. This strain produced 8.0 g/L of mevalonate from 20 g/L of glucose. We also engineered the sugar supply by displaying β-glucosidase (BGL) on the cell surface. When cellobiose was used as carbon source, the strain lacking gnd displaying BGL efficiently consumed cellobiose and produced mevalonate at 5.7 g/L. The yield of mevalonate was 0.25 g/g glucose (1 g of cellobiose corresponds to 1.1 g of glucose). These results demonstrate the feasibility of producing mevalonate from cellobiose or cellooligosaccharides using an engineered E. coli strain. © 2020 Wiley Periodicals, Inc.OBJECTIVES To examine the relationship between step-rate and energy expenditure during treadmill walking in persons with PD and then further develop a step-rate cut-point for moderate-to-vigorous physical activity (MVPA) for persons with PD. MATERIALS AND METHODS The sample consisted of 30 persons with mild-to-moderate PD and 30 controls matched by age and sex. Participants performed a 6-minute bout of over-ground walking at comfortable speed, and then completed three, 6-minute bouts of treadmill walking at 13.4 m/min slower, comfortable, and 13.4 m/min faster than comfortable speeds. The three treadmill speeds were based on the initial over-ground walking speed. The total number of steps per treadmill walking bout was recorded using a hand-tally counter, and energy expenditure was measured using a portable, indirect spirometry system. RESULTS The results indicated a strong association between step-rate and energy expenditure for persons with PD (R2 = .92) and controls (R2 = .92). The analyses further indicated a steeper slope of the association for persons with PD compared with controls (t(58) = -1.87, P less then .05), resulting in a lower step-rate threshold (t(58) = 2.19, P less then .05) for persons with PD (~80 steps·per minutes) than controls (~93 steps·per minutes). CONCLUSION Collectively, these results support the application of this disease-specific step-rate threshold for MVPA among persons with PD. This has important implications for physical activity promotion, prescription, and monitoring using accelerometers and pedometers for persons with PD to manage health and symptoms of PD. © 2020 John Wiley & Sons A/S . Published by John Wiley & Sons Ltd.Here, we discuss a series of events that led to an article in a prestigious medical journal mistakenly using a fake eponymous term that originated in a YouTube video and then spread to Wikipedia. The term has also spread to other places. In this digital world of fake news, open resources should be read discerningly in order to verify their contents. © 2020 Anatomical Society.Biomes are constructs for organising knowledge on the structure and functioning of the world’s ecosystems, and serve as useful units for monitoring how the biosphere responds to anthropogenic drivers, including climate change. The current practice of delimiting biomes relies on expert knowledge. Recent studies have questioned the value of such biome maps for comparative ecology and global-change research, partly due to their subjective origin. Here we propose a flexible method for developing biome maps objectively. The method uses range modelling of several thousands of plant species to reveal spatial attractors for different growth-form assemblages that define biomes. The workflow is illustrated using distribution data from 23,500 African plant species. In an example application, we create a biome map for Africa and use the fitted species models to project biome shifts. In a second example, we map gradients of growth-form suitability that can be used to identify sites for comparative ecology. This method provides a flexible framework that allows a range of biome types to be defined according to user needs. The method also enables projections of biome changes that emerge purely from the individualistic responses of plant species to environmental changes. This article is protected by copyright. All rights reserved.Fruit ripening is governed by a complex regulatory network. Reversible histone methylation and demethylation regulate chromatin structure and gene expression. However, little is known about the involvement of histone demethylases in regulating fruit ripening. Here, we found that the tomato SlJMJ6 encodes a histone lysine demethylase that specifically demethylates H3K27 methylation. Overexpression of SlJMJ6 accelerates tomato fruit ripening, which is associated with the upregulated expression of a large number of ripening-related genes. Integrated analysis of RNA-seq and ChIP-seq identified 32 genes directly targeted by SlJMJ6 and transcriptionally upregulated with decreased H3K27m3 in SlJMJ6-overexpressed fruit. Numerous SlJMJ6-regulated genes are involved in transcription regulation, ethylene biosynthesis, cell wall degradation, and hormone signaling. Eleven ripening-related genes including RIN, ACS4, ACO1, PL, TBG4, and a DNA demethylase DML2, were confirmed to be directly regulated by SlJMJ6 through removing H3K27me3. selleck Our results demonstrate that SlJMJ6 is a ripening-prompting H3K27me3 demethylase that activates the expression of the ripening-related genes by modulating H3K27me3, thereby facilitating tomato fruit ripening. Our work also reveals a novel link between histone demethylation and DNA demethylation in regulating fruit ripening. To our knowledge, this is the first report of the involvement of a histone lysine demethylase in the regulation of fruit ripening. This article is protected by copyright. All rights reserved.