Welcome to Dr. Kate Brilakis' Learning Portal
Any other DNA...???
Plasmids!
Bacteria rely on the FtsZ protein which forms a membrane bound ring during binary fission. FtsZ is akin to
tubulin which is found in the eukaryotic mitotic microtubules.
1. transformation
2. transduction
3. conjugation
binary fission = vertical gene transfer
Stayed tuned to explore how plasmid recombination is used to produce valuable molecules for therapeutic use and research....
Plasmids are...
1. mostly seen as circular molecules of DNA (but
may be linear and/or RNA)
2. singular or many copies per cell (># of copies
amplifies characteristics of plasmid genes)
3. may carry only a few to many hundreds of genes
4. found in more than half of all bacteria
5. also found in eukaryotes (ex: some yeast)
6. specific plasmids may be found only in closely
related bacteria (F-plasmid and enteric bacteria)
while others (P/Pseudomonas) are found in
dozens of different species of bacteria and are
associated with ABX resistance
3. conjugation
1. transformation
vertical and horizontal! Whoa
E coli exhibits a single 4.6 Mb circular chromosome. Human cells exhibit 3000 Mb arranged in 23 pairs of linear chromosomes.
Binary Fission...and then there where two
E. coli cells will divide about every 20 minutes at 37 degrees C...
that makes a billion (bajillion!) bacteria from one bacterium in only ten hours!
12/9
1. DNA adheres to cell membrane
2. DNA pulled through secretin pore by retraction of T4P protein
3. 1/2 of DNA helix moves into
cytoplasm/the other is degraded
4. The new strand H bonds to
homologous sequence/old strand
degraded
There are exceptions to the single circular chromosome...
Gram-positive Borrelia and Streptomyces exhibit linear chromosomes Gram-negative tumefaciens (agro) exhibits one linear AND one circular chromosome.
VERY cool!
More on this next week...:)
12/11
Plasmids are considered part of the
mobilome or MGEs = mobile genetic elements. MGEs are associated with antimicrobial resistance gene transfer among different bacterial species
Chromosomal DNA Replication
2. transduction
Microbial Genetics