Selective Breeding of a Genome-Scale Metabolic Network

智力优势：任何特定细胞的代谢途径形成一个相互连接的网络。研究者的目标是了解这个网络是如何随着生物体不断变化的需求而进化的。他和他的团队开发了一个模型系统，简化了适应性基因组进化的实验室研究。他们在贝氏不动杆菌ADP1中表达了光habdus luminesens的lux操纵子，该操纵子编码产生可见光的合成代谢途径，该不动杆菌在生长过程中自然地交换和重组其染色体DNA。该模型系统具有主动的自然重组系统，可实现有效的微生物育种策略，同时允许选择有助于产生可见光的基于基因的代谢性状。研究者建议指导产生更多光的菌株的进化，并通过基因组测序，微阵列分析和进化蛋白质的生化研究来研究最超模的菌株。这项工作将展示进化权衡如何通过模型合成代谢途径优化通量。这些经验可以应用于提高生物燃料、材料和其他具有经济价值的化合物的生物合成产量。更广泛的影响：许多未来的分子生物学家缺乏进行研究的财政资源。转化大肠杆菌所需的基本设备（离心机、80°C冰柜）的成本造成了巨大的进入障碍。A. baylyi天生就有能力，所以它可以在没有昂贵硬件的情况下进行转换。研究者的团队已经为这种生物创造了一种新的表达载体，并编写了软件，向用户展示如何在重叠PCR反应中组合DNA片段。一个有决心的高中生或业余爱好者可以使用这些工具在设备最低的家庭实验室中创造和表达新的基因。这项研究将激励新手科学家设计和进行自己的实验，并最终寻求正式的培训。

Intellectual Merit:The metabolic pathways of any particular cell form a single interconnected network. The Investigator's goal is to understand how this network evolves in response to the changing needs of the organism. He and his team have developed a model system that streamlines laboratory investigations of adaptive genome evolution. They expressed the lux operon of Photorhabdus luminescens, which encodes an anabolic pathway producing visible light, in Acinetobacter baylyi ADP1, which naturally exchanges and recombines its chromosomal DNA as it grows. The model system has an active natural recombination system that enables an efficient microbial breeding strategy and at the same time, permits the selection of gene-based metabolic traits that contribute to the production of visible light. The Investigator proposes to direct the evolution of strains that produce even more light, and to investigate the most hypermorphic strain by genome sequencing, microarray analysis and biochemical studies of the evolved proteins. This work will show how evolutionary tradeoffs can optimize the flux through a model anabolic pathway. These lessons could be applied to increase the biosynthetic yields of biofuels, materials, and other economically valuable compounds.Broader Impact:Many prospective molecular biologists lack the financial resources to conduct research. The cost of the basic equipment necessary to transform Escherichia coli (centrifuge, 80° C freezer) imposes a formidable entry barrier. A. baylyi is naturally competent, so it can be transformed without expensive hardware. The Investigator's team has created a novel expression vector for this organism, and has written software that shows users how to combine DNA fragments in overlap PCR reactions. A determined high school student or hobbyist could use these tools to create and express novel genes in minimally equipped home laboratories. This study will inspire novice scientists to design and conduct their own experiments, and eventually to seek formal training.