Experiment 6: Transfer
of Sulfur and Phosphorus from Parental Phage to Progeny
Per Cent Distributions of Phage
and s35 among Centrifugally Seperated Fractions of Lysates after Infection with
S35 labeled T2
|
Fraction |
Lysis at t=0
S35 |
Lysis at t=10
S35 |
Maximal
Yield |
|
|
|
|
S35 |
Phage |
|
1st low speed
sediment |
79 |
81 |
82 |
19 |
|
2nd low speed
sediment |
2.4 |
2.1 |
2.8 |
14 |
|
High speed
sediment |
8.6 |
6.9 |
7.1 |
61 |
|
High speed
supernatant |
10 |
10 |
7.5 |
7.0 |
|
Recovery |
100 |
100 |
96 |
100 |
In this experiment Hershey and
Chase labeled the protein coat of the T2 phage with radioactive S35.
Bacteria, after being grown overnigight, were infected with the S35 labelled T2
phage. To halt the growth of phage in the bacteria at the predertermined
time .02 mM HCN and 2 X 10^11 UV killed phage/mL were added to the
culture. The addition of the HCN stops the growth of intracellular phage
and the UV killed phage prevents the loss of phage progeny by adsorption to
bacterial debris. The results above were determined by taking the solution
and centrifuging it at the speeds indicated. If protein was the genetic
material then it would follow that the S35 would be found in the progeny and
would therefore be in higher ammounts in the sample with the most progeny.
However as shown above the concentration of S35 does not alter depending on the
number of progeny.
The same experiment was done with
P32 and it was found that there was a transfer of the isotope from parent to
progeny of 30%. This seems to indicate that the P35 labelled nucleic acid
may be involved in the creation of progeny.