Physiological and Ecological Significance of Multiple Ribosomal RNA Operons in Bacteria

随着对细菌基因组的深入研究，很明显，大多数基因都存在于染色体上的单个位置。最明显的例外是编码核糖体rna的基因，这种基因有多达15个拷贝。这项工作将代表首次全面努力来解释细菌中多个核糖体RNA基因的令人费解的发生。初步结果表明，rRNA基因的数量反映了不同细菌的生态策略：当养分供应波动时，那些拥有多拷贝的细菌可能会表现出越来越强的竞争适应性，而那些拥有少量拷贝的细菌可能在恒定的低营养条件下更有效地生长。pi将研究细菌基因组中核糖体RNA基因的数量是否代表了影响自然界细菌种群分布的一组相互依赖的特征中的一种特征。从这项研究中得出的原则应该适用于理解在元素的全球循环中起关键作用的细菌的分布，以及用于生物修复或与植物或动物有共生关系的细菌。

As the genomes of bacteria are explored in greater detail, it has becomeobvious that most genes are present at a single position on thechromosome. The most obvious exceptions to this observation are the genesthat encode for ribosomal RNAs, for which there are as many as 15 copies.This work will represent the first comprehensive effort to explain thepuzzling occurrence of multiple ribosomal RNA genes in bacteria.Preliminary results suggest that the number of rRNA genes reflects theecological strategies of diverse bacteria: those possessing multiplecopies may exhibit increasing competitive fitness when nutrient availabilityfluctuates, while those possessing few copies may be more efficient atgrowth under constant, low-nutrient conditions. The PIs will examine thepossibility that the number of ribosomal RNA genes in a bacterial genomerepresents one trait among a group of interdependent traits that influencethe distribution of bacterial populations in nature. The principlesderived from this research should be applicable to understanding thedistribution of bacteria that play crucial roles in the global cycling ofelements as well as bacteria used in bioremediation or those that havesymbiotic relationships with plants or animals.