Sixty years ago, the actinomycetes, which include members of the genus Streptomyces, with their bacterial cellular dimensions but a mycelial growth habit like fungi, were generally regarded as a possible intermediate group, and virtually nothing was known about their genetics. We now know that they are bacteria, but with many original features. Their genome is linear with a unique mode of replication, not circular like those of nearly all other bacteria. They transfer their chromosome from donor to recipient by a conjugation mechanism, but this is radically different from the E. coli paradigm. They have twice as many genes as a typical rod-shaped bacterium like Escherichia coli or Bacillus subtilis, and the genome typically carries 20 or more gene clusters encoding the biosynthesis of antibiotics and other specialised metabolites, only a small proportion of which are expressed under typical laboratory screening conditions. This means that there is a vast number of potentially valuable compounds to be discovered when these ‘sleeping’ genes are activated. Streptomyces genetics has revolutionised natural product chemistry by facilitating the analysis of novel biosynthetic steps and has led to the ability to engineer novel biosynthetic pathways and hence ‘unnatural natural products’, with potential to generate lead compounds for use in the struggle to combat the rise of antimicrobial resistance.

中文翻译：

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链霉菌遗传学的亮点

60 年前，放线菌（包括链霉菌属的成员，具有细菌细胞尺寸，但菌丝生长习性如真菌）通常被认为是可能的中间组，而实际上对它们的遗传学一无所知。我们现在知道它们是细菌，但具有许多原始特征。它们的基因组是线性的，具有独特的复制模式，不像几乎所有其他细菌那样是圆形的。他们通过接合机制将染色体从供体转移到受体，但这与大肠杆菌范式完全不同。它们的基因数量是大肠杆菌或枯草芽孢杆菌等典型杆状细菌的两倍，基因组通常携带 20 个或更多基因簇，编码抗生素和其他特殊代谢物的生物合成，其中只有一小部分在典型的实验室筛选条件下表达。这意味着当这些“睡眠”基因被激活时，有大量潜在有价值的化合物有待发现。链霉菌遗传学通过促进对新生物合成步骤的分析，彻底改变了天然产物化学，并导致了设计新生物合成途径的能力，从而产生了“非天然产物”，有可能产生先导化合物，用于抗击细菌生长的斗争。抗菌素耐药性。