E. Ya. Kostetsky

Phospholipids of sea worms, mollusks, and arthropods

The phospholipid composition of organs and tissues was investigated in representatives of five phyla of marine invertebrates: Annelida (Chaetopterus variopedatus, Serpula vermicularis), Echiuroidea (Urechis unicinctus), Sipunculoidea (Phascolosoma japonicum), Mollusca (Gastropoda: Tectonatica janthostoma, Neptunea polycostata; Bivalvia: Mactra sulcataria, Peronidia venuloza, Patinopecten yessoensis, Crenomytilus grayanus; Cephalopoda: Octopus conispadiceus, Todarodes pacificus), and Arthropoda (Paralythodes camtschatica, Erimacrus isenbekii, Hemigrapsus sanguineus, Pinixa rathbunii). The specificity of phospholipid distribution was shown to be related to the taxonomic position of marine invertebrates and functional properties of their organs and tissues. In Echiuroidea, Sipunculoidea, and Arthropoda, ceramide aminoethylphosphonate was found only in the digestive organs. This suggests an exogenous origin of this phospholipid.

Lipids of marine cold-water fishes

The study deals with the lipid and fatty acid compositions of the muscles, gills and liver of marine fishes inhabiting cold waters (0.5–6°C) and caught in Peter the Great Bay (3 species) and Vostok Bay (2 species), as well as with the fatty acid compositions of the main phospholipids in the muscle tissues of fish from Olyutorskii Bay (4 species). The average content of phosphatidylcholine was about 60% in muscles and in the liver and 53.8% of the sum of all phospholipids in gills. The phosphatidylethanolamine content was on the average 24.3, 25.1 and 22.3% in muscles, liver and gills, respectively. Increased contents of phosphatidylserine and sphingomyeline were recorded in the gills. The mean (S.D.) molar ratios of cholesterol/phospholipids were 0.20, 0.32, and 0.58 in the muscles, liver, and gills, respectively. It was established that phosphatidylcholine has a higher content of saturated fatty acids, whereas phosphatidylethanolamine was richer in monoenic acids and docosahexaenoic acid (DHA). It was noted that the level of polyenic fatty acids was increasing and the level of monoenic and saturated acids was decreasing in the series from gills-liver-muscles. The species with a more active mode of life were distinguished by an increased content of docosahexaenoic acid.

Thermoadaptation and fatty acid composition of main phospholipids of the small-scaled redfin tribolodon brandti under natural and experimental conditions

The fatty acid (FA) composition of the main membrane phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), was investigated in the muscle, gills, and liver of the small-scaled redfin Tribolodon brandti (Dybowskii, 1872) at different temperatures under natural and experimental conditions. It was established that a water temperature decrease in the natural habitat was accompanied by an increase in polyunsaturated fatty acid contents and the unsaturation index, mainly at the expense of FAs of the ω3 series (20:5ω3 and 22:6ω3), and by a decrease in saturated fatty acid levels in PC and PE. A similar, but less pronounced tendency was revealed in experiments with a rapid lowering of water temperature. These findings suggest the weak adaptation ability of the small-scaled redfin to a drastic shift of environmental temperature. Temperature changes produced the greatest alterations in the FA composition of phospholipids in the liver and the smallest changes occurred in muscle tissue.

The thermotropic behavior and major molecular species composition of the phospholipids of echinoderms

This study examines the molecular species composition and heat-induced crystalline-liquid crystalline phase transitions of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from the muscle tissues of six species of echinoderms that were collected during the summer: the starfishes Distolasterias nipon and Asterias amurensis, the sea urchin Strongylocentrotus intermedius, and the holothurians Eupentacta fraudatrix, Cucumaria frondosa japonica, and Apostichopus japonicus. Phospholipids (PLs) were in the liquid crystalline state, which is optimal for the functioning of the cell membranes. The use of data on the molecular species composition of PLs for the interpretation of their thermotropic behavior indicated that homeoviscous adaptation is achieved by various rearrangements in the composition of the aliphatic groups of PLs. The phase transitions of PC and PE of echinoderms (except holothurians) were symbatic. The presence of a high-temperature peak on the PC thermograms of C. frondosa japonica and A. japonicus is attributable to the melting of the phospholipid domain, which is composed of molecular species with saturated aliphatic groups. Such domains are responsible for a significant shift in the temperature ranges of the phase transitions of phospholipids of holothurians and sea urchin towards temperatures above 0°C.

Phase transitions of phospholipids as a criterion for assessing the capacity for thermal adaptation in fish

This study examines the crystal-liquid crystal phase transitions of the major phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), from muscle tissue of marine fish living at temperatures of 0–4.1°C (the Pacific cod Gadus macrocephalus, banded Irish lord Hemilepidotus gilberti, Pacific halibut Hippoglossus hippoglossus, black edged sculpin Gymnocanthus herzensteini, dark colored flounder Pleuronectes obscurus, and plain sculpin Myoxocephalus jaok), as well as of fish living at 14 and 18°C (Pacific redfin Tribolodon brandti). The PC and PE phase-transition thermograms of all the investigated species displayed specific profiles. The largest share of the thermogram area at temperatures higher than those of the habitat was found for the PC (28–40%) and PE (47–82%) of the black-edged sculpin, dark-colored flounder, and the plain sculpin, which have reduced physiological activity at low temperatures. In the Pacific cod, banded Irish lord, and the Pacific redfin, this parameter was much lower, 0–18% (PC) and 0–39% (PE). The thermotropic behavior PC and PE was symbate in all fish, except for the cod and the plain sculpin. The transition enthalpy of PC in all the investigated species was 2.8 times higher than that of PE. To interpret the varied PC and PE thermogram profiles of fish with similar fatty-acid compositions, the data on the composition of the molecular species of these phospholipids appeared to be the most informative. This study suggests that each fish species has its own strategy for thermal adaptation, which is realized through a certain set of phospholipid molecular species.

Phospholipids of the organs and tissues of echinoderms and tunicates from peter the great bay (Sea of Japan)

The phospholipid compositions of organs and tissues were determined in representatives of two phyla of marine invertebrates: Echinodermata [Asteroidea: Aphelasterias japonica (Bell, 1881), Evasterias echinosoma Fisher, 1926, Distolasterias nipon (Doderlein, 1902), Asterias amurensis Lutken, 1871; Echinoidea: Strongylocentrotus intermedius (A. Agassiz, 1863); Holothurioidea: Cucumaria frondosa japonica (Semper, 1868), Eupentacta fraudatrix (Djakonov et Baranova, 1958), Apostichopus japonicus (Selenka, 1867)], and Tunicata [Ascidia: Halocynthia aurantium (Pallas, 1787), H. roretzi (Drasche, 1884), and Styela clava (Herdman, 1881)]. The specificity of phospholipid distribution was shown to be related to the taxonomic position of marine invertebrates and the functional properties of their organs and tissues. Ceramide aminoethylphosphonate was found only in the digestive organs of all holothurians and the starfishes D. nipon and A. amurensis, suggesting its exogenous origin. Phosphatidylglycerol was found in all organs and tissues of the holothurians C. frondosa japonica and E. fraudatrix, as well as in the gastrointestinal tract of ascidians; its origin is unclear.

Individual variations of the phospholipid compositions of the organs of arthropods, echinoderms, and tunicates from peter the Great Bay of the Sea of Japan

Individual variations in the phospholipid compositions of the organs of marine invertebrates were investigated in the representatives of three phyla: Arthropoda [decapods: Paralithodes camtschaticus (Tilesius, 1815) and Erimacrus isenbeckii (Brandt, 1848)]; Echinodermata [starfishes: Distolasterias nipon (Doderlein, 1902) and Evasterias echinosoma Fisher, 1926]; and Tunicata [ascidians: Halocynthia aurantium (Pallas, 1787), H. roretzi (Drasche, 1884), and Styela clava Herdman, 1881]. The specificity of individual phospholipid variation was shown to be related to the systematic status and functional properties of the organs of marine invertebrates. Phosphatidylcholine and phosphatidylethanolamine were the least variable. Low variation of phospholipid composition was found in the liver, legs, and gills of decapods; in the liver of starfishes; and in the gonads and skin-muscular and gill sacs of ascidians. The contents of ceramide aminoethylphosphonate (CAEP) and phosphatidylglycerol (PG) showed the highest variation. These phospholipids were found but not in all individuals or organs studied. After 7 days of starvation, CAEP completely disappeared from the organs of the animals; thus, we suggest its exogenous origin.

The thermotropic behavior and fatty radical composition of major phospholipids of the tanner crab Chionoecetes bairdi Rathbun, 1924

This study examines the fatty radical (FR) composition and heat-induced crystalline to liquidcrystalline phase transitions of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from the gills, hepatopancreas, gonads, and muscle of the tanner crab Chionoecetes bairdi, which was collected in the summer at a near-bottom water temperature of 2.8°C. The location of the PC and PE thermograms below 2.8°C indicates the functionally optimal liquid crystalline state of the membrane lipid matrix. The proximity of the thermogram profiles of PC and PE from the different organs and tissues of C. bairdi and significant overlapping of the temperature areas of transitions (symbatic behavior) correlate with a similar composition of major FR and their total parameters in PC and PE. The obtained data point to the effective adaptation of the bairdi crab to low water temperatures and to the need for adaptive changes in the FR composition or change of habitat with increasing temperature. The thermotropic behavior of muscle PC, in which the greater part of the thermogram is in the temperature range from 2.8 to 32°C, suggests a potential for the tanner crab to adapt to increased temperatures.

Hemolymph cholinesterase activity in the Mussel Crenomytilus grayanus (Dunker, 1853) that was exposed to adverse natural and anthropogenic conditions

The influence of habitat conditions on the activity, the structure of the substrate specificity (the ratio of the substrate hydrolysis rates), and the kinetic parameters of substrate hydrolysis due to the effect of hemolymph cholinesterase of the mussel Crenomytilus grayanus was studied. Mussels were collected from areas that are influenced by seasonal and stationary upwelling, as well as from a polluted area. Upwelling and anthropogenic pressure were shown to alter the structure of hemolymph cholinesterase substrate specificity in mussels, up to complete loss of the ability to catalyze the hydrolysis of propionyland butyrylthiocholine. It was established that during the seasonal upwelling the efficiency of the cholinergic process in mussels is provided by a wide range of effective concentrations of the substrates and by decreasing their affinity to the enzyme. Under the conditions of chronic anthropogenic pollution, the cholinesterase of the mussel hemolymph loses its ability to hydrolyze substrates other than acetylthiocholine.

Lipid-induced changes in protein conformation as a means to regulate the immunogenicity of antigens incorporated in tubular immunostimulating complexes

Nanoparticles of tubular immunostimulating complexes (TI-complexes), which consist of the glycolipid monogalactosyldiacylglycerol (MGDG) from marine macrophytes (macroalgae and seagrasses), the triterpene glycoside cucumarioside A2-2 from the holothurian Cucumaria japonica, and cholesterol, are a promising adjuvant carrier of antigens for modern subunit vaccines. MGDG provides a lipid matrix for the antigen incorporated in TI-complexes. This paper discusses the manner in which the physicochemical properties of MGDGs isolated from different marine macrophyte species affect the conformation of two model protein antigens (Yersinia pseudotuberculosis OmpF-like porin (YOmpF) and recombinant influenza virus hemagglutinin) incorporated in TI-complexes and how the modulating effect of MGDG may be used to improve the efficacy of vaccine preparations.