26
/
en
AIzaSyAYiBZKx7MnpbEhh9jyipgxe19OcubqV5w
September 30, 2021
388848
33677
2

22h 55min, dec 10, 1952 y - Hershey and Chase

Description:

Hershey and Chase were the two scientists to confirm that DNA is made of genetic material in December of 1952. Ever since Hershey and Chase used phages to establish DNA as the carrier of genetic information in 1952, the precise mechanisms of phage DNA translocation have been a mystery [1]. Although bulk measurements have set a time-scale for in vivo DNA translocation during bacteriophage infection, measurements of DNA ejection by single bacteriophages have only been made in vitro. Here, we present direct visualization of single bacteriophages infecting individual Escherichia coli cells. For bacteriophage λ, we establish a mean ejection time of roughly 5 min with significant cell-to-cell variability, including pausing events. In contrast, corresponding in vitro single-molecule ejections are more uniform and finish within 10 s. Our data reveal that when plotted against the amount of DNA ejected, the velocity of ejection for two different genome lengths collapses onto a single curve. This suggests that in vivo ejections are controlled by the amount of DNA ejected.

Added to timeline:

8 Dec 2017
0
0
243
DNA Timeline
Mrs. Grogan's Project (May have to scroll to the 1800s)

Date:

22h 55min, dec 10, 1952 y
Now
~ 68 years ago

Images:

PayPal - The safer, easier way to pay online!logo
About & FeedbackTermsPrivacy