Polyamines Metabolism in Pseudomonas Aeruginosa

多胺(腐胺、亚精胺和精胺)是所有生物体中发现的主要有机聚阳离子，在细胞生长中具有重要的生物学作用，但人们对此知之甚少。多胺在包括RNA、DNA和蛋白质在内的大分子的生物合成中具有重要作用。多胺代谢正在被广泛研究，作为治疗人类癌症和寄生虫感染的药物设计的目标。沿着这一路线开发新的抗生素已经落后，主要是由于缺乏关于细菌中多胺分解代谢的信息。本项目的目标是阐明多胺在铜绿假单胞菌中的分解代谢和调控，多胺作为唯一的碳和氮来源可以非常有效地生长。完整的基因组序列注释和DNA微阵列的可获得性使铜绿假单胞菌成为探索多胺分解代谢的优秀模式生物。用DNA微阵列和比较基因组学方法进行的初步研究已经确定了80多个基因是由外源胍丁胺和/或腐胺差异诱导的。这些基因可能的生化功能揭示了多胺分解代谢和调节的可能途径，以及多胺代谢与其他代谢活动的联系，包括有机硫的吸收/利用和热休克反应的诱导。该项目的具体目标是：(I)继续对这些与腐胺的吸收、分解代谢和调节有关的基因进行表征；以及(Ii)寻找与亚精胺和精胺的分解代谢及其调节有关的更多基因。这些研究将通过转录图谱分析、计算机辅助数据挖掘、遗传学操作以及酶的纯化和鉴定来完成。这项研究的发现有望为多胺代谢提供新的和有意义的信息，这些信息可能有益于几个生物学领域，包括制药科学、细菌发病机制和农业。参与这个项目的学生将接受遗传学、生物化学和生物信息学的跨学科培训，从而形成对细菌生理学的综合看法。此外，DNA微阵列和转录图谱分析的数据挖掘的概念将作为课堂作业，帮助新一代学生在后基因组时代的科学工作和研究中做好准备。

Polyamines (putrescine, spermidine, and spermine) are the major organic polycations found in all living organisms with an essential but poorly understood biological role in cell growth. The importance of polyamines has been implicated in the biosynthesis of macromolecules including RNA, DNA, and protein. Polyamine metabolism is being extensively studied as a target for drug design in treatment of cancers and parasite infection in humans. Development of new antibiotics along this line has lagged behind, mostly due to the lack of information on polyamine catabolism in bacteria. It is the goal of this project to elucidate polyamine catabolism and regulation in P. aeruginosa, which can grow very efficiently on polyamine as the sole source of carbon and nitrogen. A complete genomic sequence annotation and the availability of DNA microarrays of this organism make P. aeruginosa an excellent model organism for the exploration of polyamine catabolism. Preliminary studies with DNA microarrays and comparative genomics approaches have identified more than eighty genes that are differentially induced by exogenous agmatine and/or putrescine. The putative biochemical functions of these genes revealed possible routes of polyamine catabolism and regulation as well as the linkage of polyamine metabolism to other metabolic activities, including organic sulfur uptake/utilization and induction of heat shock response. The specific aims of this project are: (i) to continue the characterization of these genes related to the uptake, catabolism and regulation of putrescine; and (ii) to identify additional genes involved in the catabolism of spermidine and spermine and its regulation. These will be accomplished through the use of transcriptional profiling analyses, computer-aided data mining, genetics manipulation, and enzyme purification and characterization.Findings from this research are expected to provide novel and significant information on polyamines metabolism which could be beneficial to several fields of biology, including pharmaceutical science, bacterial pathogenesis, and agriculture. Students participating in this project will receive cross-disciplinary training in genetics, biochemistry, and bioinformatics, and thus developing an integrative view of bacterial physiology. Further, the concepts of DNA microarrays and data mining for transcriptional profiling analyses will be classroom assignments to help prepare the new generation of students in scientific work and research in the post-genomics era.