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MEGAPLAZMIDY - PRÓBA DEFINICJI,
ROZPOWSZECHNIENIE I RÓŻNORODNOŚĆ
KODOWANYCH FENOTYPÓW
Mirosława Włodarczyk1, Grażyna
Rudzicz2
1, 2Zakład Genetyki Bakterii, Instytut Mikrobiologii, Uniwersytet Warszawski,
ul. Miecznikowa 1, 02-926 Warszawa, e-mail: miraw@biol.uw.edu.pl
Wpłynęło w czerwcu 2004
1. Definicja i ogólna charakterystyka plazmidów. 2. Próba zdefniowania pojęcia
megaplazmid. 3. Rozpowszechnienie megaplazmidów i przegląd kodowanych przez nie fenotypów. 3.1. Megaplazmidy w rizobiach
(Rhizobium, Sinorhizobium, Mesorhizobium). 3.2. Megaplazmidy w fakultatywnie litoautotroficznych bakteriach. 3.3. Megaplazmidy kataboliczne u
Pseudomonas i innych rodzajów bakterii. 3.4. Megaplazmidy warunkujące patogenność. 3.5. Inne rzadkie fenotypy i kryptyczne
megaplazmidy. 3.6. Megaplazmidy u archeonów. 4. Metody identyfikacji i badania megaplazmidów. 5. Korzyści z utrzymywania w komórce megaplazmidów. 6. Podsumowanie
Megaplasmids, attempt to give a definition, distribution and diversity of encoded phenotypes
Abstract: Megaplasmids are extremely large extrachromosomal genetic elements (plasmids) mainly spread in several genera of
a-Proteobacteria (e.g.
Rhizobium, Agrobacterium, Paracoccus and Rhodobacter), but also discovered in
b-Proteobacteria
(e.g. Ralstonia and Pseudomonas) g-Proteobacteria
(e.g. Salmonella and Escherichia), d-Proteobacteria
(e.g. Erwinia) and e-Proteobacteria
(e.g. Xanthomonas) as well as in genera belonging to other taxonomic units, including the Archaea. Megaplasmids can encode many phenotypic traits including those involved in different aspects of bacterial metabolism (e.g. lithoautotrophy, degradation of various organic substrates), resistance to different antibacterial agents as well as pathogenicity to humans, animals and plants, symbiosis of bacterial cells with plants or other
features. In this review we present a brief overview of megaplasmids - starting with the proposal of a definition, through a survey of different phenotypes associated with their presence and characterisation of experimental procedures employed in their isolation and analysis, ending with the disscussion why maintaining of such large extrachromosomal molecules might be adventageous for
bacteria.
1. Definition and general characteristics of
plasmids. 2. An attempt to define the term "megaplasmid". 3. Distribution of megaplasmids and survey of encoded
phenotypes. 3.1. Megaplasmids in rhizobia (Rhizobium, Sinorhizobium,
Mesorhizobium). 3.2. Megaplasmids in facultatively lithoautotrophic
bacteria. 3.3. Degradative megaplasmids in Pseudomonas and some other
bacteria. 3.4. Megaplasmids and pathogenicity. 3.5. Different uncommon phenotypes and cryptic
megaplasmids. 3.6. Megaplasmids in archaeons. 4. Methods adapted for studying of megaplasmids. 5. Benefits of maintaining of
megaplasmids. 6. Summary
Słowa kluczowe: fenotyp, genom plazmidowy, megaplazmid, mini-chromosom, plazmid
Key words: phenotype, plasmid genom, megaplasmid,
minichromosome, plasmid |
