Transportation of biogenic magnetic nanoparticles from prey bacteria

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Transportation of biogenic magnetic nanoparticles
from prey bacteria

• 08/03/05
• ANIL SINDHURAKAR
• DEPARTMENT OF CHEMISTRY

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A Brief Overview

• Research Hypothesis
• Experimental Tool Atomic Force Microscopy (AFM)
• The magnetic bacteria Magnetospirillum
  magnetotacticum MS-1 (prey)
• The predator bacteria Bdellovibrio bacteriovorus
  109J
• Experimental Procedures
• Experimental Results
• Importance and Significance

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Research Hypothesis

• Magnetic bacteria MS-1 will be preyed upon by
  predator bacteria 109 J
• 109 J will transport biogenic magnetic
  nanoparticles from MS-1

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Atomic Force Microscopy (AFM)

• Provides topographical images of the sample being
  studied (analogous to Braille)
• Usually operates on three modes Contact,
  Non-Contact and Tapping Mode
• The sample need not be conductive and there is no
  need to modify the sample

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AFM Contd.
Interatomic force vs. distance curve
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Magnetospirillum magnetotacticum MS-1

• Obligately microaerophillic gram negative
  bacteria
• Optimum temperature about 30oC
• Capable of biomineralization
• Synthesize nanometer scale minerals called
  magnetosomes

Magnetospirillum magnetotacticum MS-1 bacteria
under optical microscope (100X )
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Magnetosomes

• These crystals are deposits of magnetite (Fe3O4)
• Forms a linear chain of 10-20 crystals
• Each crystal ranges from 35-120 nm in diameter
• Helps create magnetic dipoles strong enough to
  render geo-magnetotaxis

DEVOUARD ET AL. BACTERIAL MAGNETITE
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Magnetosomes contd.

• AFM Image magnetosomes

Size 3umX3um
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Bdellovibrio bacteriovorus 109 J

• Gram-negative, predatory and obligately aerobic
  bacteria
• Optimal temperature 28-30oC
• Once inside the prey, forms a swollen structure
  known as bdelloplast
• 109 J can grow on wide range of gram negative
  bacteria including the genera Spirillum

Source Laurel Cosby (http//commtechlab.msu.edu)
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Bdellovibrio Contd.
Source lthttp//www.sju.edu/biology/jtudorwebImage
1.jpggt
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Experimental Procedure

• Grow DH5a on micro-pore filter
• Add 109 J on DH5a layer
• Add MS-1 to the growing layer of 109 J
• AFM and optical microscopy

Courtesy Jaclyn Schmitt 08
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Experimental Results
DH5a on small pore filter Size (10umX10 um)
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Experimental Results Contd
109 J with the bdelloplasts (arrow) Size
(10umX10um)
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Experimental Results Contd
109 J completely taking over DH5a Size 10 um X
10 um
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Experimental Results Contd
MS-1 bacteria on filter Size (10umX10um)
109 J on filter Size (10umX10um)
0.2 µm millipore filter
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Experimental Results Contd
AFM Image 109 J MS-1 on filter paper
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Project Significance Possible Applications

• Novel method of nanoparticle trasportation
• Production of carbon nanotubes
• http//virag.elte.hu/kurti/rollup.html
• Magnetic tagging of biochemicals for medical
  purposes
• Better knowledge of bacterial predation at
  hydrated air-solid interface

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ACKNOWLEDGEMENTS

• Dr. Eileen M. Spain
• Dr. Megan Nuñez, Mount Holyoke College
• Dr. Mark O. Martin, University of Puget Sound
• Howard Hughes Medical Institute
• Camille Henry Dreyfus Foundation
• Undergraduate Research Center, Occidental College
• Department of Chemistry, Occidental College
• Laboratory Colleague Jaclyn Schmitt 08