Combined genomic and structural analyses of a cultured magnetotactic bacterium reveals its niche adaptation to a dynamic environment. (October 2016)

• Record Type: Journal Article
• Authors: Araujo, Ana; Morillo, Viviana; Cypriano, Jefferson; Teixeira, Lia; Leão, Pedro; Lyra, Sidcley; Almeida, Luiz; Bazylinski, Dennis; Vasconcellos, Ana; Abreu, Fernanda; Lins, Ulysses
• Is Part Of: BMC genomics. Volume 17:Number 8(2016)
• Page Start: 363
• Page End: 375
• Publication Date: 2016-10
• Subjects: Magnetotactic bacteria -- Magnetosome -- Magnetofaba australis strain IT-1 -- Biomineralization -- mam genes -- Genome; Genomes -- Periodicals; Gene mapping -- Periodicals; Genomics -- Periodicals; Base Sequence -- Periodicals; Chromosome Mapping -- Periodicals; Genetic Techniques -- Periodicals; Sequence Analysis, DNA -- Periodicals; 572.8605
• DOI: 10.1186/s12864-016-3064-9
• Languages: English
• ISSNs: 1471-2164

Abstract

Abstract Background Magnetotactic bacteria (MTB) are a unique group of prokaryotes that have a potentially high impact on global geochemical cycling of significant primary elements because of their metabolic plasticity and the ability to biomineralize iron-rich magnetic particles called magnetosomes. Understanding the genetic composition of the few cultivated MTB along with the unique morphological features of this group of bacteria may provide an important framework for discerning their potential biogeochemical roles in natural environments. Results Genomic and ultrastructural analyses were combined to characterize the cultivated magnetotactic coccusMagnetofaba australis strain IT-1. Cells of this species synthesize a single chain of elongated, cuboctahedral magnetite (Fe3 O4 ) magnetosomes that cause them to align along magnetic field lines while they swim being propelled by two bundles of flagella at velocities up to 300 μm s−1 . High-speed microscopy imaging showed the cells move in a straight line rather than in the helical trajectory described for other magnetotactic cocci. Specific genes within the genome ofMf. australis strain IT-1 suggest the strain is capable of nitrogen fixation, sulfur reduction and oxidation, synthesis of intracellular polyphosphate granules and transporting iron with low and high affinity.Mf. australis strain IT-1 andMagnetococcus marinus strain MC-1 are closely related phylogenetically although similarity values between their homologous proteins are not very high. Conclusion Mf. australis strain IT-1 inhabits a constantly changing environment and its complete genome sequence reveals a great metabolic plasticity to deal with these changes. Aside from its chemoautotrophic and chemoheterotrophic metabolism, genomic data indicate the cells are capable of nitrogen fixation, possess high and low affinity iron transporters, and might be capable of reducing and oxidizing a number of sulfur compounds. The relatively large number of genes encoding transporters as well as chemotaxis receptors in the genome ofMf. australis strain IT-1 combined with its rapid swimming velocities, indicate that cells respond rapidly to environmental changes.