Leucine supplementation differentially enhances pancreatic cancer growth in lean and overweight mice

Kristyn A Liu1†, Laura M Lashinger1†, Audrey J Rasmussen1† and Stephen D Hursting12* Author Affiliations 1 Department of Nutritional Sciences, University of Texas at Austin, Austin, TX 78723, USA 2 Department of Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, 1808 Park Road 1c, Smithville, TX 78957, USABackground: The risk of pancreatic cancer, the 4th deadliest cancer for both men and women in the United States, is increased by obesity. Calorie restriction (CR) is a well-known dietary regimen that prevents or reverses obesity and suppresses tumorigenesis in a variety of animal models, at least in part via inhibition of mammalian target of rapamycin (mTOR) signaling. Branched-chain amino acids (BCAA), especially leucine, activate mTOR and enhance growth and proliferation of myocytes and epithelial cells, which is why leucine is a popular supplement among athletes. Leucine is also increasingly being used as a treatment for pancreatic cancer cachexia, but the effects of leucine supplementation on pancreatic tumor growth have not been elucidated. Results: Supplementation with leucine increased pancreatic tumor growth in both lean (104 ± 17 mm3 versus 46 ± 13 mm3; P <0.05) and overweight (367 ± 45 mm3 versus 230 ± 39 mm3; P <0.01) mice, but tumor enhancement was associated with different biological outcomes depending on the diet. In the lean mice, leucine increased phosphorylation of mTOR and downstream effector S6 ribosomal protein, but in the overweight mice, leucine reduced glucose clearance and thus increased the amount of circulating glucose available to the tumor. Conclusion: These findings show that leucine supplementation enhances tumor growth in both lean and overweight mice through diet-dependent effects in a murine model of pancreatic cancer, suggesting caution against the clinical use of leucine supplementation for the purposes of skeletal muscle enhancement in cachectic patients.Nutritional Science

Biology: Weird Science?

Papers Presented: The Relationship of the Second Light Treatment to Cell Germination and Polarization in Ceratopteris Fern Spores by Ao Liu Abstract: This research about the Ceratopteris richardii fern spores, which is part of the Discovery Lab in Plant Biology course at UT Austin led by Dr. Stan Roux. We focused on the relationship between the second light treatment and germination as well as polarization of the spores. Several groups of students tested different amounts of light and darkness on the influence of germination rate and the gravity response of the germinated spores. A Mathematical Model of Skeletal Muscle Regeneration by Elizabeth Stephenson Abstract: We introduce a system of seven ordinary differential equations modeling the response of healthy mammalian skeletal muscle tissue to sudden and severe damage. The system is analyzed, yielding one stable, biologically meaningful equilibrium. A set of numerical simulations is performed to illustrate the performance of the proposed equations. We conduct a sensitivity analysis to rank the parameters’ influence on the system. This model can help doctors and scientists forecast the outcomes of medicinal treatments prior to implementation. Chronically Underwhelmed: The Modern Journey Back to Happiness by Audrey Hendrickso

Developmental features and yields of three promising upland rice varieties in Zimbabwe

Three upland rice varieties: NERICA 1, 3 and 7 that were proved to be promising by previous trails in Zimbabwe, were selected as experimental materials to evaluate their developmental features and yields in irrigated conditions. The results indicate that plant height increased sharply first, and then slowly until the highest values that kept invariant. Tiller number per hill showed S-shaped curves which increased and reached relatively stable values first, then decreased slightly and finally increased again to produce the second time tiller. The leaf number per plant was apparently went up and down, which ascended to the peak values and then started to descend. NERICA 1 had many features which differed from NERICA 3 and NERICA 7, such as early maturing, short plant height, multiple tiller and multiple leave. It had the highest number of panicles and grains among the three varieties though it had nearly the same grain weight with NERICA 3 and NERICA 7. These results will be helpful to release these varieties in Zimbabwe.Keywords: Developmental feature, upland rice variety, yield, yield components, ZimbabweAfrican Journal of Biotechnology Vol. 12(21), pp. 3208-321

New bounds on light millicharged particles from the tip of the red-giant branch

Stellar energy loss is a sensitive probe of light, weakly coupled dark sectors, including ones containing millicharged particles (MCPs). The emission of MCPs can affect stellar evolution, and therefore can alter the observed properties of stellar populations. In this work, we improve upon the accuracy of existing stellar limits on MCPs by self-consistently modelling (1) the MCP emission rate, accounting for all relevant in-medium effects and production channels, and (2) the evolution of stellar interiors (including backreactions from MCP emission) using the MESA stellar evolution code. We find MCP emission leads to significant brightening of the tip of the red-giant branch. Based on photometric observations of 15 globular clusters whose bolometric magnitudes are inferred using parallaxes from Gaia astrometry, we obtain robust bounds on the existence of MCPs with masses below 100 keV.Comment: 12 pages, 8 figure

Comparison of statistical approaches to rare variant analysis for quantitative traits

With recent advances in technology, deep sequencing data will be widely used to further the understanding of genetic influence on traits of interest. Therefore not only common variants but also rare variants need to be better used to exploit the new information provided by deep sequencing data. Recently, statistical approaches for analyzing rare variants in genetic association studies have been proposed, but many of them were designed only for dichotomous outcomes. We compare the type I error and power of several statistical approaches applicable to quantitative traits for collapsing and analyzing rare variant data within a defined gene region. In addition to comparing methods that consider only rare variants, such as indicator, count, and data-adaptive collapsing methods, we also compare methods that incorporate the analysis of common variants along with rare variants, such as CMC and LASSO regression. We find that the three methods used to collapse rare variants perform similarly in this simulation setting where all risk variants were simulated to have effects in the same direction. Further, we find that incorporating common variants is beneficial and using a LASSO regression to choose which common variants to include is most useful when there is are few common risk variants compared to the total number of risk variants

Conceptual planning of urban–rural green space from a multidimensional perspective: A case study of Zhengzhou, China

The structure and function of green-space system is an eternal subject of landscape architecture, especially due to limited land and a need for the coordinated development of PLEs (production, living, and ecological spaces). To make planning more scientific, this paper explored green-space structure planning via multidimensional perspectives and methods using a case study of Zhengzhou. The paper applies theories (from landscape architecture and landscape ecology) and technologies (like remote sensing, GIS—geographic information system, graph theory, and aerography) from different disciplines to analyze current green-space structure and relevant physical factors to identify and exemplify different green-space planning strategies. Overall, our analysis reveals that multiple green-space structures should be considered together and that planners and designers should have multidisciplinary knowledge. For specific strategies, the analysis finds (i) that green complexes enhance various public spaces and guide comprehensive development of urban spaces; (ii) that green ecological corridors play a critical role in regional ecological stability through maintaining good connectivity and high node degree (Dg) and betweenness centrality index (BC) green spaces; (iii) that greenway networks can integrate all landscape resources to provide more secured spaces for animals and beautiful public spaces for humans; (iv) that blue-green ecological networks can help rainwater and urban flooding disaster management; and (v) that green ventilation corridors provide air cleaning and urban cooling benefits, which can help ensure healthy and comfortable urban–rural environments. In our view, this integrated framework for planning and design green-space structure helps make the process scientific and relevant for guiding future regional green-space structure