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X-ray microanalysis of the content of Na, K, Cl, Ca, P, S and Mg has been made in ultrasmall samples of haemolymph of the mussel Mytilus edulis living in habitats with lowered salinity. It was shown that the content of potassium in the haemolymph is higher than in the environment, both natural and artificial. Coefficient of potassium accumulation in relation to the environment increases with the decrease of external salinity.

The polyacrylamide-gel electrophoresis was used to separate the negative charged proteins from adult females of the tick Dermacentor marginatus Sulz. There were separated up to 25 protein bands from haemolymph and up to 19 bands from midgut extracts of the engorged females. The number of protein bands in excreta and eggs was 15 and 18 respectively. Haemoproteins from haemolymph, midgut and eggs were different in their electrophoretic mobility. Active and diapausing ticks showed essential differences in protein spectra and content of haemolymph (the enrichment of them was characteristic of diapausing ticks). The presence or absence of reproductive diapause affects the digestive functions and has no influence on the excretory functions of the midgut.

Effect was studied of hemolymph of snails-donors with conditioned food refusal, on learning the same habit by snails-recipients. Facilitation was observed of the recipients' learning depending on the quantity of injected hemolymph and the type of conditioned stimulus. The hemolymph of pseudo-conditioned donors inhibited the learning of intact snails-recipients. The possibility is suggested of appearance in the hemolymph of conditioned snails of one or several chemical factors, capable to facilitate elaboration of the same conditioned reflex.

A mineral components concentration in the haemolymph of the IInd- and IIIrd-stage larvae of Oedemagena tarandi depends on the physiological state of parasites. Metabolism of mineral components is most intensive in a young actively growing organism and during moulting. The moulting is characterized by the decrease in the concentration of inorganic phosphorus and potassium and by the increase of calcium, magnesium and natrium.

Changes in the concentration of ions of sodium, potassium, calcium and chlorine in the haemolymph of Lymnaea stagnalis and Planorbis corneus were studied during their infection with sporocysts and rediae of trematodes. Statistically reliable disturbances in the ion balance caused by the infection were established.

At average salinity of the environment 18.08% (-delta degrees C being equal to -0.99 degrees C) the depression of the hemolymph in P. avirostris is equal to -0.72 +/- 0.09 degrees C. Hypoosmotic regulation of marsupium fluid persists up to the formation of epipodites, after which the depression of this fluid becomes equal to that of the external medium. It is suggested that special epipodite cells are involved into osmoregulation. Similarity of hypoosmotic mechanisms in the marine cladoceran and Artemia salina is noted.

A study was conducted on the changes in sulphhydryl groups in the haemolymph of Lymnaea stagnalis infected with partenites of Opisthioglyphe ranae, Planorbis corneus infected with partenites of Cotylurus cornutus and females of Viviparus viviparus infected with partenites and larvae of Echinoparyphium petrowi. At the infection in the haemolymph of hosts were recorded statystically reliable changes in the protein sulphhydryl groups which are blocked by toxines excreted by the parasites. The reduction rate in the content of these substances depends on the localization of the parasites and infection intensity of the hosts.

Relative DNA content during the polytenization of the salivary gland nuclei of Chironomus thummi was measured by cytophotometric and cytofluorometric methods. To estimate polyteny degree, DNA content was calculated in hemocyte and spermatocyte nuclei. Chromosome polytenization is associated with the 10th-12th replication rounds. There are 4-5 replication rounds in the 1st instar, 2-3 rounds in the 2nd instar, the 3rd and the 4th instars have 1-2 rounds each. From early postembryonic development, larvae already have salivary gland nuclei representing two polyteny classes (2-2-2-4c), this heterogeneity being retained in all instars. Approximate DNA content is 0.51-0.58 picogram per a diploid set.

The proteins of the salivary gland secretion at the moment of puparium formation and the protein composition of the salivary glands, fat-body and hemolymph during the III larval instar and 12 hours prepupal period were investigated by means of electrophoresis in polyacrilamide gel, in the presence of urea. Both the qualitative and quantitative differences in the protein composition of the salivary glands were found which appeared to be due to the change of functions of the salivary glands in the process of development. 69 protein fractions were isolated in the salivary gland secretion, 40 of them being PAS-positive. A correlation was noted between the appearance of the first PAS-positive fractions at the stage of 95-100 hrs (from the moment of egg laying) and the cytological demonstration of PAS-positive secretion granules. New glycoproteins appeared in the salivary glands in prepupae (2 hrs after the puparium formation) and, later, in the hemolymph. A complicated pattern of the secretion formation in the salivary glands of the III instar larvae and possible change of its composition during metamorphosis are discussed.

To investigate the role of neurohumoral factors in acclimation of mussel muscle to a lowered salinity, studies have been made on the reaction of the intact mussel muscle and that of isolated muscle to change in the salinity from 26% to 10%. The general pattern of swelling of the adductor and the dynamics of its electrolyte composition in intact molluscs are similar to those in the isolated muscle. In the intact mussel this reaction of the adductor is slower. Acclimation of adductor cells is of the autonomic nature and does not depend on neurohumoral influences.

Marine bivalve molluscs, the mussel Mytilus galloprovincialis aud the scallop Chlamys (Flexopecten) glaber ponticus, have been injected (intramuscularly or in the haemolymph) with glucose, mammalian insulin, insulin (or insulin-like substance) from molluscs, and anti-insulin serum, checking changes in glucose and fatty acid content of the haemolymph as well as in the content of glycogen and the activity of glycogen synthetase in muscles. After glucose injections, studies were also made on the level of IRI in the haemolymph. Comparison of the data obtained in the present work with those reported earlier for freshwater bivalve molluscs suggests that: 1) metabolic shifts induced by anti-insulin serum are more rapid in vigorous scallops than in sedentary mussels; 2) molluscan insulin (or insulin-like substance) exerts the same effect on metabolic parameters of the molluscs, as mammalian insulin exerts in vertebrates.

In animals in which sodium is a predominant cation of the blood serum or haemolymph (rat, newt Triturus vulgaris, sturgeon Acipenser güldenstädti, herring Clupea pallasi, ascidian Goniocarpa rustica), its content in the body amounts up to a half of the total bulk of electrolytes; in insects with potassium type of the haemolymph, the share of sodium is equal to 6.4%. In animals of the same species, total electrolyte content (sodium, potassium, calcium, magnesium) and the relationship between separate ions were found to be remarkably constant. During ontogenetic development of the sturgeon and herring, as well as in rat embryos beginning from the 15th day of gestation, the ratio between separate cations exhibits significant conservatism.

Seasonal changes in ACh sensitivity have been studied on isolated cardiac muscle of the bivalve molluscs together with ATP content of the hemolymph and the heart. The lowest ACh sensitivity of the heart was found in August and October (KACh in August was equal to 44.0.10(-6) M). Maximum sensitivity was observed in March and at the end of August--the beginning of September (KACh in March was equal to 1.27 X X 10(-6) M); at this period of year, ATP content of the hemolymph decreases approximately 100-fold, the release of ATP from the heart in the presence of ACh being also decreased. Maximum level of ATP in cardiac muscle was found in July. It was demonstrated that most significant changes in ACh sensitivity take place during spawning, especially when sex cells are transported from the gonads into the gills, as well as during the release of glochidia from the latter. Possible causes of seasonal changes in ACh sensitivity of cardiac muscle and the role of ATP in this process are discussed.