Terahertz-Regime Attenuation Signatures in Bacillus subtilis and a Model Based on Surface Polariton Effects

A summary is provided for terahertz attenuation signatures measured in spore-laden samples of Bacillus subtilis in three different forms: 1) concentrated powder; 2) dilute powder; and 3) aerosol. In addition to a surprising spectral narrowness, some signatures also display an increase in peak signature strength (per spore) with dilution of the sample. A model is constructed to explain this phenomenology based on the presence of optical phonons and electromagnetic interaction with the spore wall. Specifically, the spheroidal Bacillus spores admit surface modes that interact with radiation via polaritonic coupling and are underdamped if isolated from each other through a dilution or aerosol levitation. Hence, the results defy longstanding assumptions that the biomolecular-related terahertz vibrations are necessarily overdamped and have immeasurably weak attenuation

[1]  A. Driks.  Maximum shields: the assembly and function of the bacterial spore coat. , 2002, Trends in microbiology.

[2]  R. Austin,et al.  Excited-state lifetimes of far-infrared collective modes in proteins. , 2001, Physical review letters.

[3]  J. Strominger,et al.  Mechanisms of enzymatic bacteriaolysis. Cell walls of bacteri are solubilized by action of either specific carbohydrases or specific peptidases. , 1967, Science.

[4]  E. Ricca,et al.  A Bacillus subtilis Secreted Protein with a Role in Endospore Coat Assembly and Function , 1999, Journal of bacteriology.

[5]  Alan W. M. Lee,et al.  Optical attenuation signatures of Bacillus subtillis in the THz region , 2004 .

[6]  A. Driks.  Bacillus subtilis Spore Coat , 1999, Microbiology and Molecular Biology Reviews.

[7]  D. Woolard,et al.  Terahertz electronics for chemical and biological warfare agent detection , 1999, 1999 IEEE MTT-S International Microwave Symposium Digest (Cat. No.99CH36282).

[8]  Arthur C. Gossard,et al.  Room temperature, THz photomixing sweep oscillator and its application to spectroscopic transmission through organic materials , 2004 .

[9]  B. Gelmont,et al.  THz-Spectroscopy of Biological Molecules , 2003, Journal of biological physics.

[10]  Dwight L. Woolard,et al.  Terahertz Fourier transform characterization of biological materials in solid and liquid phases , 2004, SPIE Optics East.

[11]  Robert R. Alfano,et al.  THz absorption spectrum of Bacillus subtilis spores , 2005, SPIE OPTO.

[12]  B. Gelmont,et al.  Sub-millimetre wave absorption spectra of artificial RNA molecules , 2003 .

[13]  W. Steen.  Absorption and Scattering of Light by Small Particles , 1999 .

[14]  J L Hesler,et al.  Submillimeter-wave phonon modes in DNA macromolecules. , 2002, Physical review. E, Statistical, nonlinear, and soft matter physics.

[15]  E. Ricca,et al.  Emerging Applications of Bacterial Spores in Nanobiotechnology , 2003, Journal of nanobiotechnology.

[16]  T. Globus,et al.  Remote detection of bioparticles in the THz region , 2002, 2002 IEEE MTT-S International Microwave Symposium Digest (Cat. No.02CH37278).

[17]  J. Strominger,et al.  Mechanisms of Enzymatic Bacteriolysis , 1967 .