CaltechTHESIS
  A Caltech Library Service

I. Irradiation experiments with Neurospora crassa. II. An electrophoretic comparison of the soluble proteins of normal and virus-infected Escherichia coli

Citation

Siegel, Albert (1951) I. Irradiation experiments with Neurospora crassa. II. An electrophoretic comparison of the soluble proteins of normal and virus-infected Escherichia coli. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-08092006-104758

Abstract

Part I:

1. A case is described and discussed in which a mutant strain of Neurospora which spontaneously reverts to wild type cannot be induced to revert by mutagenic agents.

2. The action of ultraviolet light on macroconidia of Neurospora is described.

3. The effect of heat and light post-treatment of ultra-violet irradiated macroconidia has been studied.

4. Data have been obtained which suggest that the killing effect of UV is more easily reversed by heat or light post-treatment than the mutagenic effect.

Part II:

1. The soluble proteins of Escherichia coli were extracted by disrupting the bacteria in a colloid mill and centrifuging all particulate matter out of solution.

2. The soluble proteins so obtained, were resolved by electrophoresis.

3. A comparison was made of the electrophoretic scanning patterns of the soluble proteins of non-infected bacteria, bacteria infected with bacteriophage T2 during the "eclipse" stage of infection, and bacteria infected for longer than the "eclipse" with, the following findings:

a) The amount of free-moving desoxyribonucleic acid (DNA) present in the extracts of uninfected bacteria decreases during the "eclipse" stage of infection.

b) The amount of free-moving DNA increases strikingly after the end of the "eclipse."

4. Bacteriophage particles were disrupted in the colloid mill. The increase in free moving DNA in the extracts of bacteria infected for longer than the "eclipse" was found to be due to disruption of intracellular bacteriophage particles.

5. DNA was extracted both from bacteriophage particles and from Escherichia coli. A comparison of the two DIVAS by electrophoretical and ultracentrifugal methods reveals a close similarity between them.

6. The experimental findings are discussed and several suggestions are made for further elucidating the course of virus multiplication.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Biology
Major Option:Biology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Beadle, George Wells
Thesis Committee:
  • Beadle, George Wells (chair)
  • Delbruck, Max
  • Dulbecco, Renato
  • Wildman, S. G.
  • Emerson, Sterling Howard
Defense Date:1 January 1951
Record Number:CaltechETD:etd-08092006-104758
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-08092006-104758
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3070
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:09 Aug 2006
Last Modified:26 Dec 2012 02:56

Thesis Files

[img]
Preview
PDF (Siegel_a_1951.pdf) - Final Version
See Usage Policy.

21Mb

Repository Staff Only: item control page