Transportation of biogenic magnetic nanoparticles from prey bacteria 08/03/05 ANIL SINDHURAKAR DEPARTMENT OF CHEMISTRY

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

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

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

AFM Contd…. Interatomic force vs. distance curve

Magnetospirillum magnetotacticum MS-1 Obligately microaerophillic gram negative bacteria Obligately microaerophillic gram negative bacteria Optimum temperature about 30 o C Optimum temperature about 30 o C Capable of biomineralization Capable of biomineralization Synthesize nanometer scale minerals called magnetosomes Synthesize nanometer scale minerals called magnetosomes Magnetospirillum magnetotacticum MS-1 bacteria under optical microscope (100X )

Magnetosomes These crystals are deposits of magnetite (Fe 3 O 4 ) These crystals are deposits of magnetite (Fe 3 O 4 ) Forms a linear chain of crystals Forms a linear chain of crystals Each crystal ranges from nm in diameter Each crystal ranges from nm in diameter Helps create magnetic dipoles strong enough to render geo-magnetotaxis Helps create magnetic dipoles strong enough to render geo-magnetotaxis DEVOUARD ET AL.: BACTERIAL MAGNETITE

Magnetosomes contd…. AFM Image: magnetosomes Size: 3umX3um

Bdellovibrio bacteriovorus 109 J Gram-negative, predatory and obligately aerobic bacteria Gram-negative, predatory and obligately aerobic bacteria Optimal temperature o C Optimal temperature o C Once inside the prey, forms a swollen structure known as bdelloplast 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 109 J can grow on wide range of gram negative bacteria including the genera Spirillum Source: Laurel Cosby (

Bdellovibrio Contd…. Source:

Experimental Procedure Grow DH5 α on micro- pore filter Grow DH5 α on micro- pore filter Add 109 J on DH5 α layer Add 109 J on DH5 α layer Add MS-1 to the growing layer of 109 J Add MS-1 to the growing layer of 109 J AFM and optical microscopy AFM and optical microscopy Courtesy: Jaclyn Schmitt ‘08

Experimental Results DH5α on small pore filter Size: (10umX10 um) Size: (10umX10 um)

Experimental Results Contd… 109 J with the bdelloplasts (arrow) Size (10umX10um)

Experimental Results Contd… DH5α 109 J completely taking over DH5α Size: 10 um X 10 um

Experimental Results Contd… MS-1 bacteria on filter Size: (10umX10um) 109 J on filter Size: (10umX10um) 0.2 µm millipore filter

Experimental Results Contd… AFM Image: 109 J & MS-1 on filter paper

Project Significance & Possible Applications Novel method of nanoparticle trasportation Novel method of nanoparticle trasportation Production of carbon nanotubes Production of carbon nanotubes Magnetic tagging of biochemicals for medical purposes Magnetic tagging of biochemicals for medical purposes Better knowledge of bacterial predation at hydrated –air- solid interface Better knowledge of bacterial predation at hydrated –air- solid interface

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