First report of linear megaplasmids in the genus Micrococcus
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Updated: Jun 19, 2026

Monitoring Plasmid Replication in Live Mammalian Cells over Multiple Generations by Fluorescence Microscopy
Published on: December 13, 2012
Julian R Dib1, Martin Wagenknecht, Russell T Hill
1Planta Piloto de Procesos Industriales Microbiológicos-CONICET, Av. Belgrano y Pje. Caseros, 4000 Tucumán, Argentina.
Abstract:
High-altitude wetlands (above 4200m) in the northwest of Argentina are considered pristine and extreme environments. Micrococcus sp. A1, H5, and V7, isolated from such environments, were shown to contain linear megaplasmids, designated pLMA1, pLMH5, and pLMV7, respectively. As known from linear plasmids of other actinomycetes, all three plasmids were resistant to lambda exonuclease treatment, which is consistent with having terminal proteins covalently attached to their 5' DNA ends. Electrophoretic mobility, Southern analysis, and restriction endonuclease patterns revealed pLMA1 and pLMH5 being indistinguishable plasmids, even though they were found in different strains isolated from two distant wetlands - Laguna Azul and Laguna Huaca Huasi. Analysis of 16S rDNA sequences of Micrococcus sp. A1, H5, and V7 suggested a close relationship to Micrococcus luteus. Typing of isolates was performed using fingerprint patterns generated by BOX-PCR. Plasmid-deficient strains, generated from Micrococcus sp. A1, showed a significantly decreased resistance level for erythromycin.
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