Symbiosis
Organisms establish relationships that influence their lives, survival and evolution. Among these we can mention interactions that benefit only one of the organisms in the game, and this is known as 'commensalism'. Also there are cases of 'parasitism' when one of the species takes advantage of the other becoming a parasite, delivering negative effects on the second and representing disease states. Finally, partnerships that are beneficial for both parts and are hence 'mutualistic' are highly important and are also called 'symbiotic'. These last ones are the main focus of our project here.
As a result from symbiosis organisms have colonized unexpected habitats during the history of our planet. For instance plants by associating with particular fungi partners were able to colonize land.
Certain invertebrates have been able to populate hydrothermal vents, otherwise totally inhospitable ecosystems, thanks to symbiotic chemotrophic bacteria that transform inorganic material in available nutrients.
And also corals forming the tropical reefs are capable of living in clear, shallow waters poor in nutrients because of their relationship with microbial algae (Symbiodinium) and other microbes.
A very important group of partnerships as we may see are those involving microbes.
Microbial symbioses establish a net of metabolic exchanges with the host, which ensures the health of the whole holobiont: comprising the host, and all its associated microbiome forming a biological functional system.
In general lines, symbiotic microorganisms often transform substrates otherwise not profitable, into organic nutrients that are metabolized as food and energy by the host organism. Probably without these microbial partners the host would not thrive, as it would not be capable to fulfill its minimal nutritional requirements. A well known example of mutialistic microorganims-macrooranism associations is the microflora present in cows' rumen, which allow the animal digest the cellulose in the grass.
Our own intestinal microbiota, is another clear form of symbiosis. Good bacteria in our guts build essential vitamins and other compounds, while keeping 'bad' germs and microbes from overgrowing and infesting our tissues.
And of course, coral holobionts are classic exmaples of extrict symbiotic systems in the marine realm. In their case, still many of the features of this intense metabolic exchange between the animal cnidarian host and the microbes remain to be disentangled. Some authors have proposed diagrams that intend to depict the processes taking place among the different symbiotic compartments.
Symbiotic microbes also afford with certain capacity for enhanced acclimatization to changing environments, this way, turning the holobiont system into a better 'player' for future scenarios, in the context of the Climate Change. Here we invite you all to see a bite about coral symbiosis… Enjoy it!...
0 comments