Variability of blood proteins in sturgeon ontogenesis and possible aspects of evolution in the family Acipenseridae

The developmental changes in blood proteins of three sturgeons genera Acipenser, Huso, and Pseudoscaphirhynchus (fam. Acipenseridae), have been studied using immunological methods. Heterochronicity and staging of protein development are revealed. Initially, proteins defining the specificity of immunoelectrophoregrams and subject to inconsiderable changes with fish growth are formed. The formation of transferrins is completed in the latest turn. Patterns of development do not depend on the ecology of anadromous and potamodromous forms of sturgeons. This results in the monotypic immunoelectrophoregrams of blood proteins in adult individuals of ten fish species. It is suggested that the variability of blood proteins in the ontogenesis of sturgeons reflects the evolution of this fish through consecutive adaptation to sea waters of different salinities and transition of ancient ancestors to the anadromous mode of life under conditions of oceanic salinity. The modern potamodromous sturgeons may have originated as a result of the return of anadromous forms to life in fresh waters.     

Age-related variability of serum protein antigens in sturgeons (Acipenseridae, Acipenseriformes)

We studied the variability of antigenic properties of proteins in two sturgeon species at different stages of postembryonic development. The deepest changes occurred in individual components of albumins and beta-globulins (transferrins) and were mostly related to an increased proportion of the protein accounting for these antigens. Transformation of the main component of albumins A1 into adult antigens was completed in 5-month old fry. The main component of beta-globulins A (component of transferrins) appeared in the blood flow much later than other proteins and could retain the fry features until the age of 3-4 years. Other antigens belonging to alpha1- and alpha2-globulins and the second component of transferrins were more stable and did not undergo substantial changes. The direction of ontogenetic variability of serum antigens in sturgeon fry did not depend on the habitat of adult fish in fresh or sea water.     

Age-Dependent Variation of Serum Protein Antigens in Sturgeons (Acipenseridae,Acipenseriformes)

We studied the variation of antigenic properties of proteins in two sturgeon species at different stages of postembryonic development. The deepest changes occurred in individual components of albumins and -globulins (transferrins) and were mostly related to an increased proportion of the protein accounting for these antigens. Transformation of the main component of albumins A1 into adult antigens was completed in 5-month old juveniles. The main component of -globulins A (component of transferrins) appeared in the blood flow much later than other proteins and could retain the juvenile features until the age of 3–4 years. Other antigens belonging to ₁- and ₂-globulins and the second component of transferrins were more stable and did not undergo substantial changes. The direction of ontogenetic variation of serum antigens in sturgeon juveniles did not depend on the habitat of adult fish in fresh or sea water.     

Peculiarities of the lysozyme content in cods (order Gadiformes) and flatfish (order Pleuronectiformes)

There was analyzed the content of lysozyme-the parameter of the non-specific immunity-in kidney, liver, spleen, and blood serum in 8 fish species of orders Gadiformes and Pleuronectiformes. The cods are characterized by very low level of the enzyme or by the absence of its activity in some organs and in blood serum regardless of the fish habitat. The flatfish demonstrated diversity in the content and distribution of lysozyme in the body of fish of different species. Two flatfish species inhabiting the Okhotsk Sea, with the unique distribution of the enzyme, are revealed. Their peculiarity is due, first, to the highest content of lysozyme in the blood serum among all fish studied earlier; second, to exceeding 2–3 times the enzyme amount in blood serum, as compared to the studied immunocompetent organs. The obtained results confirm the concept that among the fish there exist different related groups differing by the lysozyme activity, and, possibly, by peculiarities of the non-specific immunity as a whole.     

Variability of some blood serum beta-globulins in the life cycle of the true sturgeons (Acipenseridae)

Blood proteins of true sturgeons of three genera Acipenser, Huso, and Pseudocaphirhynchus preserving unidirectional variability in ontogenesis regardless of peculiarities of the fish ecology can indicate unity of origin of the current species. Age-related protein transformations have heterochronous character. The slowest ontogenetic development lasting 4-6 years is peculiar to one of antigens of beta-globulins. Analysis of variability of beta-globulins in the age diapason beginning from the 4-month-old fry and including adult spawned individuals indicates different functional significance of their individual components. The beta A-globulin absent at early postembryonic stages becomes the second, after albumin, quantitatively predominant antigen in the adult fish blood. The amount of beta B-globulin, like antigens of alpha 1- and alpha 2-globulins preserving relative ontogenetic stability, can decrease significantly in freshwater sturgeons due to their preparation for spawning.     

Variability of the lysozyme content in bream from the Rybinsk Reservoir in different seasons of the annual cycle

The seasonal variability of the lysozyme content has been detected in the liver, kidney, and spleen of bream. It is manifested in a higher lysozyme content in cold winter months and lower values in other seasons. It is shown that the enzyme activity is absent in blood serum of the studied fish regardless of its amount in immunocompetent organs. A high content of lysozyme in organs in the cold season of the year is not the result of the immunomodulatory effect of water temperature on this parameter but can be determined by physiological factors that do not depend on seasonal variations of the environmental temperature. It has been established that the blood serum in fish does not indicate the entire dynamics of the enzyme in the organism.     

Lysozyme Content in Organs and Blood Serum in Various Species in the Volga River

The results of study of lysozyme content in kidney, liver, spleen, and blood serum of 12 fish species in the Volga River, which belong to six different orders, are presented. It has been established that the lysozyme level in the organs and blood serum is different in representatives of different taxons. The highest enzyme content was observed in sterlet (order Acipenseriformes), while the lowest content, in burbot (order Gadiformes). The enzyme content and its distribution in visceral organs depended on fish phylogeny, but not on the type of feeding (vegetarian or predatory) and the place of the constant habitation (fresh river or salted sea water). There were seasonal and yearly variations of the lysozyme concentration in fish organs and tissues. The many-year studies have established the regularity in enzyme distribution in sturgeon fish: kidney > spleen > liver > blood serum, this regularity being independent of the sturgeon species and constant during intra- and inter-year variations.     

Lysozyme content in the organism of pike infected with cestodes

It was found that parasitizing Triaenophorus nodulosus (Pallas, 1781) affects the lysozyme content in the intestinal mucosa of pike. It is suggested that the parasite suppresses lysozyme production immediately in its locality, which may favor its successful dwelling in the hosts’ intestines. The insignificant variations of lysozyme content in the liver and blood serum of pike in the spring, summer, and autumn, on the one hand, and pronounced changes in this characteristic in the intestinal mucosa, on the other, make it possible to consider that the latter changes are related to the presence of a parasite in the intestine.     

Seasonal Dynamics of Lysozyme in the Pike Esox lucius L. in Rybninsk Reservoir

Biology Bulletin - The concentration of lysozyme in the immune organs of the pike (kidney, spleen, liver, and blood serum) was analyzed. The opposite of the intra-annual fluctuation of the...