What did Esther Lederberg discover?
Among Lederberg’s achievements was the discovery of lambda phage, a virus that infects E. coli bacteria. She published the first report of it in Microbial Genetics Bulletin in 1951, and it quickly became a significant and widely used tool for studying genetic recombination and gene regulation.
What are three facts about Esther Lederberg?
She discovered the lambda phage, a bacterial virus which is widely used as a tool to study gene regulation and genetic recombination. She also invented the replica plating technique, which is used to isolate and analyse bacterial mutants and track antibiotic resistance.
What did Esther and Joshua Lederberg?
In 1956, Esther and Joshua Lederberg were honored for their fundamental studies of bacterial genetics by the Society of Illinois Bacteriologists, which awarded them the Pasteur Medal.
Who discovered fertility factor?
The fertility factor (first named F by one of its discoverers Esther Lederberg; also called the sex factor in E. coli or the F sex factor; also called F-plasmid) allows genes to be transferred from one bacterium carrying the factor to another bacterium lacking the factor by conjugation.
Who discovered plasmid?
The word ‘plasmid’ was first coined by Joshua Lederberg in 1952. He used it to describe ‘any extrachromosomal hereditary element’. Lederberg first used the term in a paper he published describing some experiments he and his graduate student Norton Zinder conducted on Salmonella bacteria and its virus P22.
How do you do replica plating?
The technique involves pressing a velveteen-covered disk, and then imprinting secondary plates with cells in colonies removed from the original plate by the material. Generally, large numbers of colonies (roughly 30-300) are replica plated due to the difficulty in streaking each out individually onto a separate plate.
What was Esther known for?
Esther, the beautiful Jewish wife of the Persian king Ahasuerus (Xerxes I), and her cousin Mordecai persuade the king to retract an order for the general annihilation of Jews throughout the empire. The massacre had been plotted by the king’s chief minister, Haman, and the date decided by casting lots (purim).
What was the conclusion from the Lederberg experiments?
In fact, Lederberg concluded that E. coli carried only a single chromosome. This was in contrast to the cells of higher organisms, which are diploid and possess two complete complements of chromosomes.
What is the U tube experiment?
The U-tube experiment of Zinder and Lederberg showing the transfer of genetic material from one strain of bacterium to another through the agency of a bacteriophage (transduction). Zinder and Lederberg discovered transduction through an experiment popularly called U-tube experiment.
Can f+ conjugate with F +?
The bacterium is F+, but is now the recipient. When the F factor is integrated into the bacterial chromosome, it can still act as the donor in a conjugation cross. These integrated strains are called Hfr, because of the high frequency of recombination that occurs when mated with F- bacteria.
What are the 5 types of plasmids?
There are five main types of plasmids: fertility F-plasmids, resistance plasmids, virulence plasmids, degradative plasmids, and Col plasmids.
How old was Esther Lederberg when she died?
Esther Miriam Zimmer Lederberg, PhD, professor emeritus of microbiology and immunology, whose more than half-century of studies opened the door for some fundamental discoveries in microbial genetics, died Nov. 11 at Stanford Hospital of pneumonia and congestive heart failure. She was 83.
Where did Esther Lederberg go to college at?
Born in the Bronx on Dec. 18, 1922, Lederberg obtained an AB at Hunter College in New York City in 1942. She then moved to Stanford to study genetics, receiving her master’s degree in 1946.
How is the binding of lambda phage reversible?
Initially, lambda binds to LamB and the binding is reversible. This step requires only the lambda tail and the LamB protein. Next, the bound phage undergoes a change and the binding to lag LamB becomes irreversible. This nature of the change is unknown but it requires that a phage head be attached to the phage tail.
How does lambda phage identify a host bacterium?
Phage identify a host bacterium by binding or adsorption to a specific structure on the surface of the cell. Many different cell surface structures can be used as binding sites. Lambda binds to an outer membrane protein called LamB via a protein that resides at the tip of the lambda tail called the J protein.