Tuesday, January 26, 2021

The Holobiont Explained. What it is, how it functions, how it came to exist

 


 

In this clip, I do my best to explain the concept of "Holobiont," popularized first by Lynn Margulis in 1999 with her book "Symbiotic Planet." It is a powerful concept to explain how we relate with our surroundings: the whole ecosystem and our fellow human beings. If we ever arrive to assimilate this idea into the general way of thinking, we have hope to stop the aggression on everything not human (or considered not human enough) and live in peace on this planet.



Saturday, January 16, 2021

Your Skin Microbiome Loves you. Don't Kill it!

 


Good news for us, holobionts! Nature has made available for free an entire issue dedicated to the microbiome of the human skin. Plenty of interesting data about all the members of the human holobiont: the mammal and the bacteria together. 
 
There are over 1000 species of bacteria for every single mammal, and these bacteria are doing a lot of good things for the whole biont, including protecting us from external infections. One thing they say is:
"researchers have uncovered evidence of extensive communication between bacteria, skin cells and immune cells. These interactions help to reinforce and repair the barrier formed by the skin, bolster the body’s defences against infection and tamp down excess inflammation."
So, wash your hands only when it is really necessary and don't use aggressive chemicals: otherwise you'll weaken your resistance to bad microbes. Your skin microbiome loves you, don't kill it!
 
Here is the link to the issue and, as always, onward, fellow holobionts!

Monday, January 11, 2021

Holobiont Science: Sometimes a Little Vague, but Always Interesting

 


Holobiont science is sometimes a little vague, but always interesting. Here is an example.In this paper, http://www.zoologia.hu/list/Why_infest.pdf, Rozsa and Apari argue that head lice in humans is a useful symbiont because it generates an immune response that helps protect humans from body lice, which can be dangerous as vector for harmful bacteria. (the photo above is from the paper)
 
It is an interesting story where you learn that there are at least two types of lice living with humans. And you learn that apes have only one kind, probably because they are uniformly hairy. Rozsa and Apari go on suggesting that the "touching heads" human habit has the specific purpose of diffusing health lice in such a way to spread the immunity to body lice. Apes, they say, don't touch each other's heads because they don't have such a need. 
 
Which is, as I said, very interesting, but is it true? Honestly, it gives you the idea that the authors are piling up one hypothesis after the other, none of them being really supported by data. For instance, in the places where I live, there is no habit of touching heads as a form of salutation or an expression of friendship. Then, are we sure that apes touch heads less frequently than humans do? I don't think we have solid statistics on that point. Besides, why are body lice dangerous, but not head lice? One more mystery of holobionts! 
 
But it is nevertheless a nice idea that adds a little more to the complexity of the idea of holobionts. And the picture that illustrates the paper (in lieu of non-existing data) is truly charming. Two distinguished professors exchanging lice. Wonderful!

Saturday, January 2, 2021

The Chimera and the Holobiont

 

This is a rather ambitious project of mine where I examine a subject I have been working on for a long time, the Chimera myth, from several viewpoints: myths, lore, history, symbolism, and more. But I also try to take a look at the Chimera from the view point of a beloved concept of mine, that of the "Holobiont."

You probably already know that the term "chimera" has a specific meaning in biology: an organism having more than a single set of genes. But these creatures are normally considered some kind of freaks, the result of the work of some mad scientists or the like. But chimeras (in the biological sense) are just a special case of "holobionts" -- with holobionts defined as creatures composed of organisms of different species. And that's clearly the case of the Chimera. 

In this clip I try to outline how the concept of a multiple organism, a holobiont, is a general concept in ecology, but also in fields such as memetics, where "memes" act indeed as holobionts, having "sex" with each other and exchanging information to create new memes. Or new myths, it is the same thing. Or the whole ecosystem. In the end, we are all chimeras!

I hope you may find the clip interesting. It was not easy to make it: I am not a professional and I have to apologize if it is a little rough at some moments. But I did my best. I have also to thank the Frilli Gallery in Florence and Ms. Clara Marinelli for having allowed me to film their full-size replica of the Chimera of Arezzo.

Who

Ugo Bardi is a member of the Club of Rome, faculty member of the University of Florence, and the author of "Extracted" (Chelsea Green 2014), "The Seneca Effect" (Springer 2017), and Before the Collapse (Springer 2019)