Physics & Astronomy ETDs

Publication Date

7-9-1973

Abstract

The recently developed technique of autocorrelation of intensity fluctuations of Rayleigh (quasi-elastically) scattered light allows measurement of some dynamic properties of particles in solution. The origin of the intensity fluctuations and the form of the correlation spectra for various situations are discussed. The apparatus and methods are described along with methods of data reduction and sources of error. Measurements were made using a Spectra-Physics Model 125 (50mW) He-Ne laser (6328Å) in conjunction with a Saicor 43A 400 channel correlation and probability analyzer. The diffusion coefficient of cyanometmyoglobin was found to be D20, w = (9.47 ± 0.28) x 10-7cm2/sec at 2.9mg/ml protein concentration. The diffusion constant of cyanomethemoglobin (HbCN) was found to increase with decreasing protein concentration below 1 mg/ml, indicating dissociation into subunits. The effect of inorganic salts (MgCl2) on dissociation was studied for HbCN. The diffusion constant of HbO2 was found to be (6.30 ± 0.04) x 10-7 cm2/sec at 9.9mg/ml protein concentration, and was found to remain constant within 2% when the pH of the solvent was increased from 7 to 10.5. The diffusion coefficient of HbCN was measured for concentrations of protein from 0.43 to 280 mg/ml. The hydrodynamic theory of swimming motions in bacteria is discussed and a theory for correlation spectral forms seen in light scattered from translating and rotating bacteria developed. Correlation spectra were measured in media of different viscosity for a nonchemotactic mutant of Escherichia coli which indicate that it is not the translational modes of motion which dominate the spectral shape, but those due to rotation. Four types of E. coli and one of Salmonella cholera suis were studied and the differences in their spectral curves discussed, which show the effect of the motions which have been associated with the chemotactic response. Increasing the environmental temperature was found to increase the motility of cheC 497 E. coli by 5%/°C.

Degree Name

Physics

Level of Degree

Doctoral

Department Name

Physics & Astronomy

First Committee Member (Chair)

Seymour Samuel Alpert

Second Committee Member

Christopher Dean

Third Committee Member

Howard Carnes Bryant

Project Sponsors

Grant GB-31110X from the National Science Foundation

Language

English

Document Type

Dissertation

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