Susanne Wedlich

Hardly the most attractive of titles but absolutely fascinating. I had some idea of the importance of mucus membranes and such like but virtually no in depth understanding of the ubiquitous importance of hydrogels or slimes in our biology. Well, it's mainly biology but there are overlaps with geology...as for example where sand gets glued together by exertions from diatoms and thus stabilises the sea shore giving flat surfaces. Where the gel is not present and the sand is loose then ridges and dunes are formed ...thus impacting the nature of the channels etc in the sea.
This is a translation from the German and it's a pretty good translation (in the sense that it flows well...I can't speak to the accuracy) though occasionally I had to read things twice to get the meaning. Wedlich (the author), I think gets a bit too carried away with literary allusions and the role of slime in literature but that may appeal to some people. To me it was a bit of an irritant....I wanted to get onto the real nature of slimes and their chemistry. It's a book that is crying out for illustrations and diagrams. I'd really like to see some chemical structures for these hydrogels...especially the differences between different sorts of hydrogels but there are no illustrions. Likewise, the many examples of animals and microbes that make use of slimes of various sorts would lend themselves to having photographs. I thought that the lack of pictures was a great loss to what would have made a superb book. However, I guess the cost benefit didn't stack up from the publishers perspective.
A few little gems that struck me on reading :
"Invertebvrates make up some 97 percent of all species". (I suspect this does not include fungi, bacteria or viruses).
The term slime covers pseudonyms such as gel, biofilm, mucilage, glycocalyx, soil crusts, etc.
Slime is little more than stiff water with a molecular framework of polymers
Secreted slimes lie the mucus in our stomachs have a large content of mucins...in whatever life form the mucin tend to be similar ...a bit like a bottlebrush with a long single protein stretched out with a large number of specific sugars....nine of them... (glycans) attached along it's length. These glycans seem to play a significant role in biology. For example, with cystic fibrosis the glycands are "starkly altered.There are four different hydrogel systems in the human body.
Every cell in the human body exhibits a glycocalyx which is involved in various cellular processes.......from membrane organisation to cancer progression
Cancer cells don't just roam around at random they need a suitable microenvironment of supporting cells embedded in an altered extracellular matrix.
The gels/slime that surround our organs and cells act as major barriers to invader pathogens....and parasites but for one parasite (the human embryo) the immune defences are lowered ...though the umbilical cord has a protective function via its "wharton's jelly".
In Victorian England the colon was considered a "banal disposable tube".
The seemingly useless appendix probably keeps in store a sample of our micro diversity to repopulate after a wipe-out in the large intestine.
We form an inextricably linked community with our microbes......Microbial diversity in our internal ecosystems seems to make us more resilient....though they are constantly adapting and changing.
Stromatolites form via a biofilm ,,,which is a high functioning city for microbes....it's an entire ecosystem.
Around 1.8 billion years ago the oxygen content of the air and sea dropped dramatically and for a billion years earth was probably very stable (not much change) however, the ocean floor was covered in microbial mats as far as the deep sea....and evolution found a protected hiding hole in these microbial mats .....which contributed to the explosive growth in species in the Cambrian period.
The yearly amount of carbon that ends up in the deep (as agglomerated flakes) from jellyfish, ctenophores and free living tunicates could rival the amount the EU releases into the atmosphere in the form of greenhouse gases.
Unicellular diatoms produce about 20% of the world's oxygen through photosynthesis and use a sticky glue to attach themselves to grains of sand overnight. In the morning they detach and get washed away. But the sand stays glued together ..keeping whole coastlines in shape.
Amphibians first line of defence against pathogens is it's outer mucus layer...the microbiota are thought to play an important role as well.
I liked the story of the American herpetologist who kept snakes around the house ...."the rattlesnake....once you get to know him is a loveable creature"....oh yeah? she died when her Indian cobra bit her...admittedly startled by a camera flash.
Mucilages have been found in shrubs and flowering plants but also in algae, lichen, mosses and ferns. They're secreted by roots, shoots, leaves, and flowers with a myriad of functions.
A form of giant Mexican corn takes up nitrogen directly via its thick, aerial roots which encircle the steamed are covered in a thick hydrogel.
The volume of the deep biosphere is thought to be twice as large as all the oceans combined. It could comprise 70 percent of all bacteria and unicellular arches on the planet, with the biomass of microbes potentially outweighing that of humans nearly 400 times.
Using skimmers to remove micro plastics from the ocean surface could destroy 90 percent of this neuston layer.
According to one researcher soil crusts with their associated nitrogen fixing microbes could account for up to half of the nitrogen fixing that is essential for plants.
A report by wildlife conservation of the European Union showed that investment per vertebrate species has been 468 times higher than that for invertebrates."
Overall, a fascinating book and it opened up a whole new world for me. I also checked in a number of text books which I have on Chemistry, Biochemistry, The Cell and one on Phycology (algae) and there was virtually nothing about hydrogels or mucus...a little about the chemical structure of the glycocalyx .......so seems to me that the text books have a fair bit of catching up to do. Happy to give the book 5 stars but it would be much much better with diagrams and photos. (and maybe less about slimes in literature).… (mehr)