title: Magnetic field is the dominant factor to induce the response of Streptomyces avermitilis in altered gravity simulated by diamagnetic levitation.
abstract: BACKGROUND
  Diamagnetic levitation is a technique that uses a strong, spatially varying magnetic field to simulate an altered gravity environment, as in space. In this study, using Streptomyces avermitilis as the test organism, we investigate whether changes in magnetic field and altered gravity induce changes in morphology and secondary metabolism. We find that a strong magnetic field (12T) inhibit the morphological development of S. avermitilis in solid culture, and increase the production of secondary metabolites.
  
  
  RESULTS
  S. avermitilis on solid medium was levitated at 0 g*, 1 g* and 2 g* in an altered gravity environment simulated by diamagnetic levitation and under a strong magnetic field, denoted by the asterix. The morphology was obtained by electromicroscopy. The production of the secondary metabolite, avermectin, was determined by OD(245 nm). The results showed that diamagnetic levitation could induce a physiological response in S. avermitilis. The difference between 1 g* and the control group grown without the strong magnetic field (1 g), showed that the magnetic field was a more dominant factor influencing changes in morphology and secondary metabolite production, than altered gravity.
  
  
  CONCLUSIONS
  We have discovered that magnetic field, rather than altered gravity, is the dominant factor in altered gravity simulated by diamagnetic levitation, therefore care should to be taken in the interpretation of results when using diamagnetic levitation as a technique to simulate altered gravity. Hence, these results are significant, and timely to researchers considering the use of diamagnetic levitation to explore effects of weightlessness on living organisms and on physical phenomena.
authors: Chinese Academy of Sciences Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Beijing, People's Republic of China.
authors: Mei
authors: M
authors: Liu
authors: Hong
authors: H
authors: Gao
authors: Peng
authors: P
authors: Shang
authors: Xianlong
authors: X
authors: Zhou
authors: Elizabeth
authors: E
authors: Ashforth
authors: Ying
authors: Y
authors: Zhuo
authors: Difei
authors: D
authors: Chen
authors: Biao
authors: B
authors: Ren
authors: Zhiheng
authors: Z
authors: Liu
authors: Lixin
authors: L
authors: Zhang
mesh_terms: D007559:Ivermectin / Q000031:analogs & derivatives / Q000378:metabolism; D008280:Magnetics; D008854:Microscopy, Electron; D008962:Models, Theoretical; D013302:Streptomyces / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D014893:Weightlessness
chemical_list: D007559:Ivermectin; C019264:avermectin