What's the latest scientific data suggesting?

The great majority otherwise you would be ill. For example, when you get diarrhoea, pathogens have got the upperhand, in population terms.

Is there evidence that "parasites"(symbiotic organisms?) alter one's mood?

 

Who or what is "in charge"?

19 minutes ago, geordief said:

Is there evidence that "parasites"(symbiotic organisms?) alter one's mood?

Parasites have no benefit to the host. Symbiotic relationships are mutually beneficial, generally. Gut bacteria can have a significant effect on behaviour by interacting with the host to produce the neurotransmitter.serotonin.

Quote

...Wanting to home in on mechanisms that could be involved in this interesting collaboration between microbe and host, the researchers began looking for molecules that might be key. They identified several particular metabolites—products of the microbes' metabolism—that were regulated by spore-forming bacteria and that elevated serotonin from EC cells in culture. Furthermore, increasing these metabolites in germ-free mice increased their serotonin levels.

Previous work in the field indicated that some bacteria can make serotonin all by themselves. However, this new study suggests that much of the body's serotonin relies on particular bacteria that interact with the host to produce serotonin, says Yano. "Our work demonstrates that microbes normally present in the gut stimulate host intestinal cells to produce serotonin," she explains. http://www.caltech.edu/news/microbes-help-produce-serotonin-gut-46495

Both the host and commensal bacteria regulate each others activities. They are part of the hosts critical makeup.

Couple of recent interesting articles related to this:

https://www.quantamagazine.org/how-bacteria-help-regulate-blood-pressure-20171130/

https://www.quantamagazine.org/what-bacteria-can-tell-us-about-human-evolution-20171205/

1 hour ago, Strange said:

Couple of recent interesting articles related to this:

https://www.quantamagazine.org/how-bacteria-help-regulate-blood-pressure-20171130/

https://www.quantamagazine.org/what-bacteria-can-tell-us-about-human-evolution-20171205/

Cool stuff. The line between bacteria and human is extremely blurry when you think how important mitochondria are to our existence, originally being autonomous organisms themselves; the same with chloroplasts in plants.

Quote

The theory holds that mitochondria, plastids such as chloroplasts, and possibly other organelles of eukaryotic cells represent formerly free-living prokaryotes taken one inside the other in endosymbiosis, around 1.5 billion years ago. In more detail, mitochondria appear to be related to Rickettsiales proteobacteria, and chloroplasts to nitrogen-fixing filamentous cyanobacteria.

Among the many lines of evidence supporting symbiogenesis are that new mitochondria and plastids are formed only through binary fission, and that cells cannot create new ones otherwise; that the transport proteins called porins are found in the outer membranes of mitochondria, chloroplasts and bacterial cell membranes; that cardiolipin is found only in the inner mitochondrial membrane and bacterial cell membranes; and that some mitochondria and plastids contain single circular DNA molecules similar to the DNA of bacteria.

https://en.wikipedia.org/wiki/Symbiogenesis

 

Edited December 10, 20178 yr by StringJunky