Discovered in the 1920s by Andre Gratia, colicins are water-soluble proteins that when produced by certain proteins, can kill
similar kinds of bacteria. Initially believed to be promising anti-bacterial agents, colicins soon proved to be poorly suited
for the task and for decades were largely ignored by researchers. In 1963, Masayasu Nomura demonstrated that colicins are
able to kill bacteria by damaging the membrane of the bacterial cell. As a result of Nomura's work, Luria turned his focus
to colicins. While on leave at the Institut Pasteur in Paris in 1963, Luria found that one particular colicin, E1, made bacterial
cells incapable of accumulating the substances they required to maintain the cell by effectively blocking the function of
transport of proteins through the membrane. After he returned to MIT, the colicin work became the focus of his laboratory.
Along with Kay Fields, Luria first looked into the possible alterations of the transport and accumulation of b-D-galactosidase--an
enzyme that splits lactose into glucose and galactose--by colicin-treated E. coli cells. They found that colicin E1 drastically
inhibited the energy-dependent accumulation process, while the rate of transport of ortho-nitrophenyl galactoside (ONPG)--a
substrate for detection of b-galactosidase activity--was hardly affected. They further noted that the accumulation of a-methylglucoside
was insensitive to colicin E1, and was thus an indication that glycolysis did proceed in colicin-inhibited cells.
Item is a photocopy.
Number of Image Pages:
7 (882,628 Bytes)
1969-01 (January 1969)
Fields, Kay L.
Luria, Salvador E.
Periodical: Fields, Kay L., and Salvador E. Luria. "Effects of Colicins E1 and K on Transport Systems." Journal of Bacteriology
97, 1 (January 1969): 57-63. Article. 7 Images.
American Society for Microbiology
Reproduced with permission of the American Society for Microbiology.
Reproduced with permission of the American Philosophical Society.