Tuesday, October 28, 2008
Tuesday, May 27, 2008
Genome Transplant!
Imagine the implications for the scientific world if a genome could be transplanted into an organism!
Apparently this is no longer a thing of science fiction movies. Researches have effectively turned one species of bacterium into another.
Craig Venter and his colleagues defined a minimal genome with less than 400 genes in a simple bacterium, M. Mycoides. The team then managed to transfer this genome to a parasite called M. Capricolum.
The proteins these organisms produced suggested that they completely transformed into M. Mycoides.
Basically in order to complete this process the researchers took a strain of M. Mycoides resistant to the antibiotic Tetracycline, broke open the cells and digested the proteins, leaving only the circular chromosomes containing the DNA.
These chromosomes were then incubated with M. Capricolum cells in a medium that encourages cell membranes to fuse. It is speculated that some M. Capricolum cells fused together encapsulating an M. Mycoides chromosome as they did so.
Finally the cells were treated with tetracycline so that only those with the M. Mycoides genome would survive.
The transplant was effective in about 1/150 000 cells, which was enough to give healthy colonies of the transformed bacteria that did not contain the M. Capricolum DNA.
It is not entirely clear how the M. Mycoides took over the cells. However researchers do suggest that the cells containing multiples genomes soon divide with each daughter cell containing only one genome. Those that had the M. Capricolum genome would have been killed off by the tetracycline leaving only those with M. Mycoides genome remaining.
This fascinating process is a mere step in Craig Venter’s plan to create a genome from scratch. He says the first synthetic bacterium is to be created in rapid time!
Keep your eye out!
Original article from New Scientist
http://www.newscientist.com/article.ns?id=dn12157
Peter Aldhous
Apparently this is no longer a thing of science fiction movies. Researches have effectively turned one species of bacterium into another.
Craig Venter and his colleagues defined a minimal genome with less than 400 genes in a simple bacterium, M. Mycoides. The team then managed to transfer this genome to a parasite called M. Capricolum.
The proteins these organisms produced suggested that they completely transformed into M. Mycoides.
Basically in order to complete this process the researchers took a strain of M. Mycoides resistant to the antibiotic Tetracycline, broke open the cells and digested the proteins, leaving only the circular chromosomes containing the DNA.
These chromosomes were then incubated with M. Capricolum cells in a medium that encourages cell membranes to fuse. It is speculated that some M. Capricolum cells fused together encapsulating an M. Mycoides chromosome as they did so.
Finally the cells were treated with tetracycline so that only those with the M. Mycoides genome would survive.
The transplant was effective in about 1/150 000 cells, which was enough to give healthy colonies of the transformed bacteria that did not contain the M. Capricolum DNA.
It is not entirely clear how the M. Mycoides took over the cells. However researchers do suggest that the cells containing multiples genomes soon divide with each daughter cell containing only one genome. Those that had the M. Capricolum genome would have been killed off by the tetracycline leaving only those with M. Mycoides genome remaining.
This fascinating process is a mere step in Craig Venter’s plan to create a genome from scratch. He says the first synthetic bacterium is to be created in rapid time!
Keep your eye out!
Original article from New Scientist
http://www.newscientist.com/article.ns?id=dn12157
Peter Aldhous
Monday, May 26, 2008
POSSIBLE LINK FOUND BETWEEN GENE EXPRESSION AND ABUSE VICTIMS WHO COMMIT SUICIDE
A study by a team of scientists led by Moshe Szyff at the McGill University of Montreal has discovered a possible link between childhood abuse and differential gene expression compared to unabused people as observed in the brain of postmortem suicide victims.
Gene expression is turned off by the addition of methyl groups to dinucleotides. Environmental factors such as diet and stress may influence the addition of such groups. Szyff and colleagues revealed that rat pups neglected by their mothers have high methylation levels compared to those who were well cared for, indicating maternal care, could affect regulation of gene expression.
Eleven age and gender matches with a normal upbringing who had died from sudden accidents were compared to 13 suicide victims’ brains’ who had a history of neglect and/or abuse.
The part of the brain studied controls memory and mood and is known as the Hippocampus. Previous studies indicate that this area of the brain is relatively smaller in abuse victims. The genes examined in the hippocampus are found to be involved in controlling protein-produced RNA molecules. It was discovered that these specific genes in suicide victims are switched off; indicating less activity in the hippocampus, raising the question of whether methylation levels and the deactivation of certain genes is linked to suicide.
Barbara Wronski
s4176479
Gene expression is turned off by the addition of methyl groups to dinucleotides. Environmental factors such as diet and stress may influence the addition of such groups. Szyff and colleagues revealed that rat pups neglected by their mothers have high methylation levels compared to those who were well cared for, indicating maternal care, could affect regulation of gene expression.
Eleven age and gender matches with a normal upbringing who had died from sudden accidents were compared to 13 suicide victims’ brains’ who had a history of neglect and/or abuse.
The part of the brain studied controls memory and mood and is known as the Hippocampus. Previous studies indicate that this area of the brain is relatively smaller in abuse victims. The genes examined in the hippocampus are found to be involved in controlling protein-produced RNA molecules. It was discovered that these specific genes in suicide victims are switched off; indicating less activity in the hippocampus, raising the question of whether methylation levels and the deactivation of certain genes is linked to suicide.
Barbara Wronski
s4176479
Reference:
Alison Motluk(2008)GENETICS: Abuse may trigger gene changes found in suicide victims. http://www.newscientist.com/channel/life/genetics/dn13844-abuse-may-trigger-gene-changes-found-in-suicide-victims.html [accessed 27/05/08]
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