[Kinetic parameters of Na,K-ATPase in the gills of crabs adapted to freshened sea water]. / Kineticheskie parametry Na, K-ATPazy v zhabrakh krabov, adaptirovannykh k opresnennoi vode.

The dependence of Na,K-ATPase activity on concentrations of ATP, Na+, K+, Mg2+ and ouabain in the membrane preparations of crab gills was studied. The first group of crabs was adapted to freshened (25%) and the second one--to normal (100%) sea water. A 40-day adaptation of crabs to the freshened sea water results in an increase of maximal activity of Na,K-ATPase, but does not affect the enzyme affinity for ATP, Na+, K+, Mg2+ and ouabain, as well as its cooperative properties. It is assumed that adaptation of crabs to freshened sea water is accompanied by an accumulation of Na, K-ATPase in the epithelial cell membranes or crab gills without causing any qualitative changes of the enzyme.

[Adenosine triphosphatase activity in the organs of the crab Hemigrapsus sanguineus, acclimated to sea water of different salinity]. / Adenozintrifosfataznaia aktivnost' v organakh u kraba Hemigrapsus sanguineus, akklimiruemogo k morskoi vode razlichnoi solenosti.

In crabs acclimated to low salinity, the activity of Na, K-ATPase from the gills increases; the activity also increases in the antennal glands after acclimation of the animals to high salinity. The activity of Na, K-ATPase in the abdominal ganglion and in the heart does not depend on the salinity to which crabs had been acclimated. Changes in the activity of Mg-ATPase in the gills and antennal glands associated with acclimation of crabs to sea water with different salinity correspond to those in the activity of Na, K-ATPase.

[Relationship between the ionic composition of blood and urine and the salinity of the external environment of the crab Hemigrapsus sanguineus]. / Zavisimost' ionnogo sostava krovi i mochi ot solenosti vneshnei sredy u kraba Hemigrapsus sanguineus.

Studies have been made on the dependence of sodium, potassium, magnesium and calcium concentrations of the blood and urine on the salinity of the external milieu in the crab H. sanguineus. Effective regulation of sodium and potasssium balance at low salinities was found. Within the salinity range investigated, magnesium level in the blood is maintained at lower level as compared to that in the environment. At low salinities, regulation of potassium and sodium concentrations in the blood is monitored by extrarenal mechanisms. Uber high salinity conditions, regulation of magnesium and potassium concentrations in the blood is accomplished at the expense of the activity of antennal glands. Calcium concentration in the blood is regulated by extra-renal mechanisms. The antennal glands affect regulation of calcium balance.