Posts Tagged ‘bacteria’

Your coffee maker is a bacterial breeding ground

Friday, December 18th, 2015

Your coffee maker is a #bacterial breeding ground Bugs love the warm water but it appears cleaning is effective

“The researchers only counted the number of different bacteria types in their samples, not the total cells. A CBS investigation earlier this year found bacteria including staphylococcus and E. coli on the Keurig machines it swabbed. More than half were harboring millions of bacteria cells.

Bacteria appear to thrive in the high temperatures and chemical makeup of the coffee making process itself. Neither user behavior, the type of coffee brewed, nor frequency of the machine’s use seemed to affect the composition of the bacteria present.”


Genome-Wide Comparison of Medieval and Modern Mycobacterium leprae

Monday, December 9th, 2013

Genome-Wide Comparison of Medieval & Modern M. #leprae, reveals ~1600 #pseudogenes, w/ slightly more in modern strain

Most bacteria will have some pseudogenes in their genome, maybe, you know, in Mycobacterium tuberculosis, for instance a close relative, there are 4,000 genes
present and perhaps 20 pseudogenes. In Mycobacterium leprae, there are 1,600 real
genes and as many pseudogenes. For me, this has always been puzzling, because bacteria
generally tend to, once a function has been lost, the corresponding genes are usually
eliminated and we see the genome shrinking. This hasn’t happened in Mycobacterium
leprae, because there’s still such a huge number of pseudogenes present. And that makes
me think that maybe Mycobacterium leprae emerged in this form only very recently and
that there hasn’t therefore been sufficient time for these pseudogenes to be lost.
However, this is clearly speculation, and it needs to be tested by further experiment. For
instance, looking at older samples might be helpful because the analysis described in the
recent Science paper shows that there are more, a few more pseudogenes present in
modern strains of Mycobacterium leprae than there were in medieval European strains.
So if we could go back a few thousand years more, we might find that actually there were
a couple more functional genes at that particular point.
Now is there any evidence that the successive number of pseudogenes contributes to
either its slow growth or its resistance to growing in the lab or its just kind of long
standing plague on humanity?
Yes, I think while there’s no experimental evidence to prove that the pseudogenes are
responsible for the slow growth, I think it’s highly likely that they do contribute because
lots of very essential functions have been lost, and this means that M. leprae, for instance,
has difficulty in acquiring iron because it’s lost the genes required for iron uptake.

Michael Specter: Exploring the Human Microbiome : New Yorker

Saturday, November 3rd, 2012

– Very much argues the dirt is good case

Evidence of non-random mutation rates suggests an evolutionary risk management strategy : Nature : Nature Publishing Group

Tuesday, April 24th, 2012
Does it apply to humans ?