5 ms·
This is all very preliminary, a couple of quotes from the article stood out to me: > Roberts wondered whether bacteria from the gut could have leaked from bloo
by tlow 8y ago
This is all very preliminary, a couple of quotes from the article stood out to me:
> Roberts wondered whether bacteria from the gut could have leaked from blood vessels into the brain in the hours between a person’s death and the brain’s removal.
> Roberts acknowledges that her team still needs to rule out contamination. For example, could microbes from the air or from surgical instruments make it into the tissue during brain extraction?
- SubiculumCode 8y agoBut you left off supporting evidence from mouse models: "So she looked at healthy mouse brains, which were preserved immediately after the mice were killed. More bacteria. Then she looked at the brains of germ-free mice, which are carefully raised to be devoid of microbial life. They were uniformly clean."
- b_tterc_p 8y agoI had no idea we could sustain germ-free life. That's so cool. The obvious evidence that seems to be missing, however, would just be to extract brain tissue from a living animal, no?
- singularity2001 8y agothat very much contradicts my model of organisms as well. I thought we ARE 95% germs, DNA wise.
- jessriedel 8y agoProkaryotes are thousands of times smaller in mass/volume, so most cells (and maybe even most DNA) can be bacteria while these are nonetheless minor players.
- etatoby 8y agoA side note to passing readers: thousands of times smaller in mass or volume means of course only tens of times smaller in diameter, which agrees with the pictures shown in the article and elsewhere.
- jessriedel 8y agoYea. The comparison of humans to cockroaches is a useful intuition. Or blue whales to cats.
- Bartweiss 8y agoThis is definitely part of it, the estimates claiming 90% bacteria by cell count end up suggesting perhaps a half gallon of actual bacterial volume. As far as DNA, I think the parent stat can't hold for base pairs. Not as a volume issue, but because mammalian genomes are ~3 orders of magnitude larger than bacterial ones. Even at a 10:1 cell count, our base pairs would be 99% human. Most importantly, though, the 10:1 stat is just outdated. Newer estimates put the number around 1.3:1 instead. https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002533 https://journals.plos.org/plosbiology/article?id=10.1371/jou...
- jessriedel 8y agoThis comment was super interesting, thank you.
- marcosdumay 8y agoThat does nothing to rule out contamination from a different tissue.
- SubiculumCode 8y agoDifferent methods. Same result. But sure, you can't prove a negative.
- go_blue_13 8y agoHow could one possibly rule out contamination by this logic?
- marcosdumay 8y agoBy using some procedure that controls for contamination from a different tissue, instead of having no relation to it.
- supercheetah 8y agoThe truth is that it will probably be hard to find conclusive evidence unless we look for this in a living brain.