title: The ancient small mobilizable plasmid pALWED1.8 harboring a new variant of the non-cassette streptomycin/spectinomycin resistance gene aadA27.
abstract: The small mobilizable plasmid pALWED1.8 containing a novel variant of the streptomycin/spectinomycin resistance gene aadA27 was isolated from the permafrost strains of Acinetobacter lwoffii. The 4135bp plasmid carries mobА and mobC genes that mediate its mobilization by conjugative plasmids. The nucleotide sequences of mobА and mobC are similar to those of mobilization genes of the modern plasmid pRAY* and its variants, which contain aadB gene, and are widespread among the pathogenic strains of Acinetobacter baumannii. Almost identical pALWED1.8 variants were detected in modern environmental Аcinetobacter strains. A highly similar plasmid was revealed in a strain of Acinetobacter parvus isolated from mouse intestine. Furthermore, we discovered six previously unidentified variants of plasmids related to pALWED1.8 and pRAY* in public databases. In contrast to most known variants of aadA which are cassette genes associated with integrons, the aadA27 variant harbored by pALWED1.8 is a non-cassette, autonomously transcribed gene. Non-cassette aadA genes with 96% sequence identity to aadA27 were detected in the chromosomes of Acinetobacter gyllenbergii and several uncharacterized strains of Аcinetobacter sp. Moreover, we revealed that the autonomous aadA-like genes are present in the chromosomes of many gram-positive and gram-negative bacteria. The phylogenetic analysis of amino acid sequences of all identified AadA proteins showed the following: (i) cassette aadA genes form a separate monophyletic group and mainly reside on plasmids and (ii) chromosomal non-cassette aadA genes are extremely diverse and can be inherited both vertical and via horizontal gene transfer.
authors.affiliation: Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, 123182 Moscow, Russia. Electronic address: enlyss@hotmail.com.
authors.forename: Anton
authors.initials: A
authors.lastname: Kurakov
authors.affiliation: Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, 123182 Moscow, Russia. Electronic address: mindlin@img.ras.ru.
authors.forename: Sofia
authors.initials: S
authors.lastname: Mindlin
authors.affiliation: Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky Ave. 33, bld. 2, 119071 Moscow, Russia. Electronic address: mortu@yandex.ru.
authors.forename: Alexey
authors.initials: A
authors.lastname: Beletsky
authors.affiliation: Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, 123182 Moscow, Russia. Electronic address: shcherbnat@rambler.ru.
authors.forename: Natalya
authors.initials: N
authors.lastname: Shcherbatova
authors.affiliation: Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky Ave. 33, bld. 2, 119071 Moscow, Russia. Electronic address: rakitin@biengi.ac.ru.
authors.forename: Andrey
authors.initials: A
authors.lastname: Rakitin
authors.affiliation: Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky Ave. 33, bld. 2, 119071 Moscow, Russia. Electronic address: sun_shine92@mail.ru.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Ermakova
authors.affiliation: Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, Leninsky Ave. 33, bld. 2, 119071 Moscow, Russia. Electronic address: mardanov@biengi.ac.ru.
authors.forename: Andrey
authors.initials: A
authors.lastname: Mardanov
authors.affiliation: Institute of Molecular Genetics, Russian Academy of Sciences, Kurchatov sq. 2, 123182 Moscow, Russia. Electronic address: petrova@img.ras.ru.
authors.forename: Mayya
authors.initials: M
authors.lastname: Petrova
mesh_terms: D040981:Acinetobacter baumannii / Q000187:drug effects* / Q000235:genetics*; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001483:Base Sequence; D005798:Genes, Bacterial / Q000235:genetics; D008826:Microbial Sensitivity Tests; D009713:Nucleotidyltransferases / Q000235:genetics*; D010957:Plasmids / Q000235:genetics* / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D000198:Spectinomycin / Q000494:pharmacology*; D013307:Streptomycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D000198:Spectinomycin; D009713:Nucleotidyltransferases; C022678:streptomycin 3''-adenylyltransferase; D013307:Streptomycin
keywords: Acinetobacter lwoffii; Bacteria adaptation; Chromosomal genes; Permafrost strains