Generally what happened, we are giving extreme conditions to them for initial isolation but later we have only "tolerants" not the "true philes". Why??
Thank you in advance.
Dear Abhas,
What kind of extremophiles you are working on?
Generally, most of the extremophiles after few sub-culturing lose their potential of growing at extreme conditions and the other reason is their response to laboratory conditions.
Dear Abhas,
Your question is not completely clear for me, nontheless, trying to answer.
True extremophiles, especially alkali- or acidophiles may be very sensitive to cultivation media composition and other growth conditions, such as aeration, pressure, light regime and so on, because in nature they usually live in very special environmental conditions not only dealt with the factors you mention. It depend on its natural habitats, isolation sites. During the isolation process some conditions might be inadequate so the desirable cultures might fail to grow.
It is really difficult task to isolate real extremophiles and find appropriate growth medium and other conditions for them. And also get full life cycle. And that's the reason it's easy to loose them during sub-culturing
Anyway, I wish you good luck.
Dear Avinash,
I never observed Extremophiles that loose their ability to grow under extreme conditions as real extremophiles cannot grow under neutral conditions and being cultivated only under extreme ones.
Can you give some examples?
Extremotolerants are versatile in nature. On the contrary, being extremophilic is an obligate life style which limits their population as well the extremophilic species richness. . Therefore the more metabolically flexible tolerants are present in very large number leading to their isolation in the media.
And the media that we use for isolation often is a routine culture media in which the more flexible tolerants are able to easily grow compared to extremophiles. Also, extremophiles usually taking longer time to grow (weeks) until which the incubation period is not extended.
These are two reasons I observed which causes the high frequency of extremotolerants to be isolated when we are actually trying isolating extremophiles. Hope this helps.
Thank you all for the nice and informative discussions regarding.
Actually I worked on two kinds of extreme i.e. cold and alkaline. But I was trying to isolate the true ones but at the end I got the tolerants.
For psychrophiles, I took the primary isolation temperature 15 degree, but while I go through many articles they usually suggest to do so in 5 degree instead of 15 degree for primary isolation of psychrophiles.
For the alkaliphiles, I primarily isolate in Horikoshi media which has pH about 10.3 . Still some of those isolate can grow at 5-6 pH. which means they are again alkalitolerants.
Thank you for all suggestions may be due to lab conditions it may be happened.
-Grazie
-AKM
It is logical to think that in a colony of microorganisms, all members do not behave homogeneously. The most tolerant ends, take longer to adapt to new environmental conditions. Less extreme tolerant are those who have more adaptability. In that case, these would be the dominant strains in new crops. Therefore, tolerant ends would not cultivated predominantly
You may try alkaline agar medium developed by our research group. It works good for alkaliphilc fungi.
Our alkaliphiles cannot grow on other medium.
For bacteria you may find media in Dmitriy Yu. Sorokin' articles
https://www.researchgate.net/profile/Dimitry_Sorokin
Article Heleococcum alkalinum a new alkali-tolerant ascomycete from ...
And this one
Article Sodiomyces alkalinus, a new holomorphic alkaliphilic ascomyc...
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