Osmoregulation in Protists

[Kjell.Fagerbakke at im.uib.no]

Intresting item
I just want to point out a few topics. First the definition 
of osmoregulation, which deal with how an organism cope with 
variation in salinity. Just in case, only few marine organism
will find a situation where such variation occure(someone call it 
salt stress), and a regulation by definition will not occure. 

A fact is though that any naked organism (wether they are prostis 
or not do not matter) will be restricted to isoton with the 
environment due to lack of walls.

On the other hand Ions may be used activly in in the metabolism 
of an organism. For all metabolism an ion gradient is benefittal,
so the isotony may just be regarded to the turgor controll, and
various ions may have gradient(s) over the membrane(s). I've measure
lack of Sodium in a naked dinoflagelate. Although this is not yet
I suppose such lack of or extra content of the various mobile ions
is videspread even in protists.

Kjell Magne Fagerbakke