N. V. Ushakova

Proteinases of the calpain family in water invertebrates and fishes

Activity of Ca2+-dependent proteinases, or calpains (EC 3.4.22.17), was estimated in a wide range of aquatic invertebrates (Oligochaeta, Hirudinea, Crustacea, Insecta, Gastropoda, Bivalvia) and vertebrates (Osteichthyes). Detected molecular properties of calpains from the tissues of different species allow the consideration of the complications of calpain structural organization and regulatory mechanisms in invertebrates and vertebrates from a comparative-evolutionary perspective. Certain conclusions can be drawn about changes in the functional role of this proteolytic system in cell metabolism.

The effects of geomagnetic storms on proteinase and glycosidase activities in fish intestinal mucosa

It has been demonstrated that the glycosidase activity of cyprinoid fishes (carp and crucian carp) exposed to a geomagnetic storm for up to 20 h considerably decreases; however, the proteinase activity is weakly altered (a statistically significant decrease in the enzyme activity has been observed only in fasting fish). An in vitro study of the effects of individual half hour intervals of the geomagnetic storm that correspond to the main and recovery phases on the same enzyme activities demonstrates the opposite trend. Independently of the experimental conditions, geomagnetic storms have been shown to influence the enzyme system of fasting fish negatively.

The effect of magnetic fields on the activity of proteinases and glycosidases in the intestine of the crucian carp Carassius carassius

It has been demonstrated by the example of the crucian carp (Carassius carassius) that a 1-hour stay of fish in a combined magnetic field with resonance parameters for calcium ions decreases the proteolytic and amylolytic activities of their intestinal enzymes. It has been found that a 1-hour exposure to a combined magnetic field with resonance parameters for potassium ions has almost no effect on the activity of proteinases, but it decreases the amylolytic activity. It has been noted that the activity of proteases and glycosidases is lower under hypomagnetic conditions. Upon the inversion of the vertical component of the geomagnetic field, the proteolytic activity of the intestinal mucosa in C. carassius decreases, while the amylolytic activity becomes higher compared to the control. Possible effects of magnetic fields on the activity of digestive hydrolases in fish are discussed.

Modulation of Ca2+ dependent protease activity in fish and invertebrates by weak low-frequency magnetic fields

Results of experiments addressing the effects of weak low-frequency magnetic fields on intracellular Ca2+ dependent proteinases (calpains) from invertebrates and fish are discussed. Exposure of live animals to weak low-frequency magnetic fields with parameters chosen to induce the resonance of Ca2+ ions led to a significant decrease of calpain activity in the animals investigated. The physical factor studied also caused partial loss of activity in preparations of Ca2+ dependent proteinases obtained from invertebrates and fish. The phenomenon discovered is in accordance with the interference model of the effect of weak low-frequency magnetic fields on biological objects.

Calcium-dependent proteinases of some invertebrates and fish

In comparative-evolutionary aspect, the experimental data are considered about activity, biochemical properties, and peculiarities of structural organization of proteins of the calpain family in some invertebrates and fish. Peculiarities of calpain-like proteins of invertebrates—the predecessors of calpains of higher animals are revealed. By the example of the studied taxa, there is traced complication of the structural organization and mechanisms of control of the calpain activities, which reflects stages of molecular evolution of the protein family.

Modulation of Ca2+-dependent proteolysis under the action of weak low-frequency magnetic fields

The study aimed to determine the molecular targets of magnetic fields in living objects. Timedependent effects of weak low-frequency magnetic fields tuned to the parametric resonance for calcium ions were studied on model organisms (fish, whelk). The dynamics of Ca2+-dependent proteinase activity under the exposure to magnetic fields with given parameters and minimal time of exposure in order to achieve inactivation of these proteinases was determined as well. As hyperactivation of Ca2+-dependent proteinases is a basis of degenerative pathology development, the therapeutic potential of weak low-frequency magnetic fields enabling the modulation of Ca2+-dependent proteinase activity is supported.

The effect of weak low-frequency magnetic fields on the intracellular calcium-dependent proteinases of fish

The in vivo and in vitro effects of weak, low-frequency magnetic fields with resonance parameters for calcium ions upon intracellular calcium-dependent proteinases (calpains) in the crucian carp (Carassiuscarassius (L.)) and roach (Rutilus rutilus (L.)) were studied. It has been revealed that the impact of a weak lowfrequency magnetic field leads to considerable decrease in the activity of calpains in the fish skeletal muscles and brain.

Effects of Hypomagnetic Conditions and Reversed Geomagnetic Field on Calcium-Dependent Proteases of Invertebrates and Fish

The effects of hypomagnetic conditions and the reversal of the geomagnetic field (GMF) on intracellular Ca2+-dependent proteases (calpains) of fish and invertebrates have been studied in vivo and in vitro. It is found that the intravital exposure of examined animals to hypomagnetic conditions leads to a significant decrease in its calpain activity. The activity of preparations of calcium-dependent proteases was tested in separate experiments. It is shown that preparations of Ca2+-dependent proteases from invertebrates and fish are also inactivated substantially under effect of hypomagnetic conditions. The ambiguous results obtained in the experiments with a reversed GMF do not make it possible to discuss the biological response of calcium-dependent proteases to the reversal of the GMF.

Proteinases of potential objects of fish nutrition

The review analyzes data on activities and characteristics of proteinases of digestive system and of cathepsins of various tissues in potential preys of fish differing by the character of nutrition. There are presented data on multiple forms and molecular mass of proteinases, species-related differences, dependence of proteinase activities on the life cycle stages, type of nutrition, and biochemical food composition as well as on temperature and pH optima. Role of cathepsin in evolution of enzymatic systems providing degradation of food protein components in fish is discussed.