title: Magnetic properties of Acidithiobacillus ferrooxidans.
abstract: Understanding the magnetic properties of magnetotactic bacteria (MTBs) is of great interest in fields of life sciences, geosciences, biomineralization, biomagnetism, and planetary sciences. Acidithiobacillus ferrooxidans (At. ferrooxidans), obtaining energy through the oxidation of ferrous iron and various reduced inorganic sulfur compounds, can synthesize intracellular magnetite magnetosomes. However, the magnetic properties of such microorganism remain unknown. Here we used transmission electronmicroscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) assay, vibrating sample magnetometer (VSM), magneto-thermogravimetric analysis (MTGA), and low temperature magnetometry to comprehensively investigate the magnetic characteristics of At. ferrooxidans. Results revealed that each cell contained only 1 to 3 magnetite magnetosomes, which were arranged irregularly. The magnetosomes were generally in a stable single-domain (SD) state, but superparamagnetic (SP) magnetite particles were also found. The calcined bacteria exhibited a ferromagnetic behavior with a Curie Temperature of 454 °C and a coercivity of 16.36 mT. Additionally, the low delta ratio (δFC/δZFC=1.27) indicated that there were no intact magnetosome chains in At. ferrooxidans. Our results provided the new insights on the biomineralization of bacterial magnetosomes and magnetic properties of At. ferrooxidans.
authors.affiliation: College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, 163319, PR China.
authors.forename: Lei
authors.initials: L
authors.lastname: Yan
authors.forename: Shuang
authors.initials: S
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Chen
authors.forename: Weidong
authors.initials: W
authors.lastname: Wang
authors.forename: Yanjie
authors.initials: Y
authors.lastname: Wang
authors.forename: Hongyu
authors.initials: H
authors.lastname: Li
mesh_terms: D042763:Acidithiobacillus / Q000737:chemistry* / Q000166:cytology / Q000648:ultrastructure; D060328:Magnetic Phenomena; D055944:Magnetosomes / Q000648:ultrastructure; D013052:Spectrometry, X-Ray Emission; D013696:Temperature; D013818:Thermogravimetry; D014961:X-Ray Diffraction
keywords: Acidithiobacillus ferrooxidans; Biomineralization; Curie temperature; Magnetic properties; Magnetosome