Neimark H, Kirkpatrick B C
Department of Microbiology and Immunology, Morse Institute for Molecular Biology, State University of New York, Brooklyn 11203.
Mol Microbiol. 1993 Jan;7(1):21-8. doi: 10.1111/j.1365-2958.1993.tb01093.x.
We describe the isolation and characterization of full-length chromosomes from non-culturable plant-pathogenic, mycoplasma-like organisms (MLOs). MLO chromosomes are circular and their sizes (640 to 1185 kbp) are heterogeneous. Divergence in the range of chromosome sizes is apparent between MLOs in the two major MLO disease groups, and chromosome size polymorphism occurs among some related agents. MLO chromosome sizes overlap those of culturable mycoplasmas; consequently, small genome size alone cannot explain MLO non-culturability. Hybridization with cloned MLO-specific chromosomal and 16S rRNA probes detected two separate chromosomes in some MLO 'type' strains. Large DNA molecules that appear to be MLO megaplasmids were also demonstrated. The ability to characterize full-length chromosomes from virtually any non-culturable prokaryote should greatly facilitate the molecular and genetic analysis of these difficult bacteria.
我们描述了从不可培养的植物致病类支原体生物（MLOs）中分离全长染色体并对其进行表征的过程。MLO染色体呈环状，其大小（640至1185千碱基对）各不相同。在两个主要的MLO疾病组中的MLO之间，染色体大小范围的差异很明显，并且在一些相关病原体中存在染色体大小多态性。MLO染色体大小与可培养支原体的大小重叠；因此，仅基因组小并不能解释MLO的不可培养性。用克隆的MLO特异性染色体探针和16S rRNA探针杂交，在一些MLO“类型”菌株中检测到两条独立的染色体。还证实了似乎是MLO大质粒的大DNA分子。从几乎任何不可培养的原核生物中表征全长染色体的能力应极大地促进对这些难培养细菌的分子和遗传分析。
