| Abstract: | Effect of an autumn-winter decrease of the environmental temperature on changes of the content of free amino acids and reducing sugars was studied in tissue fluids of the freshwater mollusc L. stagnalis. At a decrease of the temperature to 4 and 0 degrees C at the autumn period, concentration of free alanine rose several times; an increase of histidine, glutamate, glycine, and serine concentrations was less pronounced. Accumulation of methionine, leucine, isoleucine, tyrosine, and phenylalanine was revealed at 0 degree C. In the state of long hypobiosis (at 4 degrees C), pools of all amino acids fell 4-8 times; essential amino acids, except for lysine, were not detected at all. Both at the summer and at the autumn periods, high concentrations of free fructose and glucose were revealed. In the process of hypobiosis the fructose pool decreased almost 35, while the glucose pool--12 times. Maltose that was absent in summer was found at 4 and 0 degree C as well as after 2.5 months of hypobiosis. The changes of the studied parameters in L. stagnalis in response to hypothermia are compared with the corresponding parameters of changes in cryoresistant animals in response to negative temperatures. |
