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.     

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.     

Phylogenetic diversity of bacteria associated with ascidians in Eel Pond (Woods Hole, Massachusetts, USA)

Recent studies have revealed that many marine invertebrates are closely associated with diverse microorganisms, frequently resulting in the production of compounds of biomedical interest. Thus far, ascidians have not been widely examined for the presence of bacterial associations, although the production of secondary metabolites is well documented. In the present study, we examined the gonad of Molgula manhattensis and the tunic surfaces of Botryllus schlosseri, Didemnum sp., and Botrylloides violaceus for the presence of associated bacteria. These ascidians are common inhabitants of the coastal ocean of Cape Cod, Massachusetts. We used denaturing gradient gel electrophoresis (DGGE) as well as cloning and sequencing of 16S rDNA to analyze the microbial communities. There is a strong evidence that spiroplasma-like bacteria colonize the gonad of the solitary ascidian M. manhattensis. The bacteria might be vertically transmitted and may be involved in the production of secondary metabolites that deter predators of the ascidians. The bacterial communities found on the tunic surfaces of the colonial ascidians were found to be more diverse. However, in all cases the bacterial communities were predominated by alpha-proteobacteria. Alpha-proteobacteria related to the obtained sequences have been identified as symbionts in a variety of hosts, suggesting a specific role for these bacteria. However, based on our data it is difficult to differentiate between persistently and only transiently associated bacteria. Overall, this study demonstrates that ascidian species are associated with diverse bacterial populations. Future studies will aim to elucidate the precise relationships between bacteria and ascidians and to identify bioactive compounds that might be produced as a result of these relationships.     

The control of the development of a marine benthic community by predation on recruits

Recruitment is an important process in regulating many marine benthic communities and many studies have examined factors controlling the dispersal and distribution of larval immigrants. However, benthic species also have early post-settlement life-stages that are dramatically different from adult and larval stages. Predation on these stages potentially impacts measured recruitment and the benthic populations and communities that ultimately develop.We examined the consequences of post-settlement predation on 1-day-old to 1-month-old recruits of sessile invertebrates at two field sites in southern New England. One site (Breakwater) was in a protected area with few predators and the other (Pine Island) was <1 km away in an open coast area with three different predator guilds: small and large invertebrates and fish. The Breakwater site had been dominated for >10 years by colonial and solitary ascidians. These species were absent from the Pine Island site which was dominated by bryozoans. Our goal was to examine whether post-settlement predation influenced the development and subsequent structure of the epifaunal community.Here we examine long-term changes in community development resulting from post-settlement predation, and contrast these results to those of earlier experiments examining the reductions in observed recruitment by post-settlement predation. Our first long-term experiment examined natural community development at the two sites and whether transplanted communities changed when exposed to the different levels of predation at these sites. The communities that developed at both sites were consistently different from each other and similar to resident communities at their respective sites. On panels transplanted from the Breakwater to Pine Island, solitary ascidians and the colonial ascidian, Botryllus schlosseri, suffered high mortalities on both caged and uncaged treatments, indicative of predation by small predators that could enter cages. Some solitary ascidians did survive inside cages and the colonial ascidian, Botrylloides violaceus, became dominant on all transplanted treatments. On panels transplanted from Pine Island to the Breakwater, ascidians invaded and dominated all treatments except those that were originally caged at Pine Island.In the second long-term experiment, natural communities were allowed to develop on panels exposed at the Breakwater for 1, 2, 3, and 4 weeks. Each set was transplanted to three treatments at Pine Island: open uncaged pilings, caged pilings to exclude fish and large invertebrates, and racks suspended above the bottom to exclude all predators. When 1-week-old communities were transplanted, after 2-3 weeks only bryozoans were found on the open and caged pilings, while colonial ascidians dominated the suspended rack treatment. When older 2-week-old communities were transplanted, colonial ascidians also became dominant in the caged piling treatment and when 3- and 4-week-old communities were transplanted colonial ascidians dominated all three treatments. Solitary ascidians were never abundant on open pilings exposed to fish and large benthic invertebrate predators.Post-settlement predator-prey interactions involved newly settled and juvenile life-stages of a variety of prey species and many invertebrate and vertebrate predator species. The effects of these interactions on recruitment did result in differences in the development and eventual species composition of the communities, even though predators had little if any effect on the adults of the prey species.     

Hatching glands in cephalopods – A comparative study

Hatching of embryos from their eggs involves either mechanical and/or chemical support. In particular enzymes are widely used in the animal kingdom to weaken the egg layers and facilitate the embryo's escape. Although numerous morphological and biochemical studies exist on the hatching glands of invertebrates (such as sea urchins, ascidians, insects) and vertebrates (teleosts, amphibians, and mammals), little is known about the morphology of the hatching glands (Hoyle organs) in cephalopod hatchlings.In this study, the internal gland structure and the external appearance of the Hoyle organ are compared among several cephalopod species (Idiosepius pygmaeus; Euprymna scolopes; Sepia officinalis; Loligo gahi; Sepioteuthis lessoniana; Architeuthis sp.; Octopus vulgaris; Tremoctopus gracilis; Argonauta hians). In almost all cases the glandular system is restricted to the posterior part of the dorsal mantle surface. Only Octopus and Argonauta lack a specific glandular structure in this body region and the animals apparently use other mechanisms to penetrate the egg layers.In all decapod species (Idiosepius; Euprymna; Sepia; Loligo; Sepioteuthis; Architeuthis) as well as in Tremoctopus only one specific cell type is present in the Hoyle organ, which synthesizes granular material. The secretory droplets are more or less uniform in electron density in Idiosepius, Euprymna and Tremoctopus but exhibit translucent inclusions in the other decapods. The time of gland development, first synthesis of secretory products and later degeneration after hatching vary between the species.The present study contributes to our knowledge of glandular systems in cephalopods and allows comparison with hatching structures in other invertebrates and vertebrates.     

Biological function of unique sulfated glycosaminoglycans in primitive chordates

Glycosaminoglycans with unique sulfation patterns have been identified in different species of ascidians (sea squirts), a group of marine invertebrates of the Phylum Chordata, sub-phylum Tunicata (or Urochordata). Oversulfated dermatan sulfate composed of [4-α-L-IdoA-(2-O-SO₃)^?1 → 3-β-D-GalNAc(4-OSO₃)^?1]_n repeating disaccharide units is found in the extracellular matrix of several organs, where it seems to interact with collagen fibers. This dermatan sulfate co-localizes with a decorin-like protein, as indicated by immunohistochemical analysis. Low sulfated heparin/heparan sulfate-like glycans composed mainly of [4-α-L-IdoA-(2-OSO₃)^?1 → 4-α-D-GlcN(SO₃)^?1 (6-O-SO₃)^?1]_n and [4-α-L-IdoA-(2-O-SO₃)^?1 → 4-α-D-GlcN(SO₃)^?1]_n have also been described in ascidians. These heparin-like glycans occur in intracellular granules of oocyte assessory cells, named test cells, in circulating basophil-like cells in the hemolymph, and at the basement membrane of different ascidian organs. In this review, we present an overview of the structure, distribution, extracellular and intracellular localization of the sulfated glycosaminoglycans in different species and tissues of ascidians. Considering the phylogenetic position of the subphylum Tunicata in the phylum Chordata, a careful analysis of these data can reveal important information about how these glycans evolved from invertebrate to vertebrate animals.     

Biochemical studies of the excitable membrane of Paramecium tetraurelia. II. Phospholipids of ciliary and other membranes

The phospholipids of cilia and deciliated bodies of Paramecium tetraurelia were isolated and characterized. 1-alkyl-2-acyl-sn-glycero-3-(2′-aminoethyl) phosphonate (GAEPL), phosphatidylethanolamine, and 1-alkyl-2-acyl-sn-glycero-3-phosphorylcholine (GPC) were the major lipids of Paramecium, and the minor lipids included phosphatidylinositol, cardiolipin, ceramide-(2-aminoethyl) phosphonate (CAEP), ceramide phosphorylethanolamine (COPE) and four sphingolipids whose identity was not established. The deciliated bodies contained 4% cardiolipin, 15% GAEPL, 41% phosphatidylethanolamine, 30% GPC and 3% each of CAEP and phosphatidylinositol; the cilia contained no cardiolipin, 24% GAEPL, 37% phosphatidylethanolamine, 15% GPC, 15% CAEP, 3% phosphatidylinositol, 2% COPE and small amounts (approx. 1%) of the four uncharacterized sphingolipids. No alteration in phospholipid composition was found among cells harvested in the various stages of growth. The phospholipids of six Paramecium mutants of three distinct phenotypes (pawn, paranoiac and fast) were also examined. Only one significant difference was found on comparison of the whole cell, deciliated body and cilia fraction of the mutants with the analogous fractions from wild type cells: the fast mutant, fA 97, had two extra, minor phospholipids (approx. 2%) in the deciliated body fraction that were tentatively identified as 1,2-diacyl-sn-glycero-3-(2′-aminoethyl) phosphonate (AEPL) and 1-alkyl-2-acyl-sn-glycero-3-phosphorylethanolamine (GPE).     

Analysis of Stomach and Gut Microbiomes of the Eastern Oyster (Crassostrea virginica) from Coastal Louisiana,USA

We used high throughput pyrosequencing to characterize stomach and gut content microbiomes of Crassostrea virginica, the Easter oyster, obtained from two sites, one in Barataria Bay (Hackberry Bay) and the other in Terrebonne Bay (Lake Caillou), Louisiana, USA. Stomach microbiomes in oysters from Hackberry Bay were overwhelmingly dominated by Mollicutes most closely related to Mycoplasma; a more rich community dominated by Planctomyctes occurred in Lake Caillou oyster stomachs. Gut communities for oysters from both sites differed from stomach communities, and harbored a relatively diverse assemblage of phylotypes. Phylotypes most closely related to Shewanella and a Chloroflexi strain dominated the Lake Caillou and Hackberry Bay gut microbiota, respectively. While many members of the stomach and gut microbiomes appeared to be transients or opportunists, a putative core microbiome was identified based on phylotypes that occurred in all stomach or gut samples only. The putative core stomach microbiome comprised 5 OTUs in 3 phyla, while the putative core gut microbiome contained 44 OTUs in 12 phyla. These results collectively revealed novel microbial communities within the oyster digestive system, the functions of the oyster microbiome are largely unknown. A comparison of microbiomes from Louisiana oysters with bacterial communities reported for other marine invertebrates and fish indicated that molluscan microbiomes were more similar to each other than to microbiomes of polychaetes, decapods and fish.     

Expression of amino acid transporter genes in developmental stages and adult tissues of Antarctic echinoderms

Epithelial cells in the body wall of adult and developmental stages of marine invertebrates absorb dissolved organic material directly from seawater. Despite over a century of study, little is known about the molecular biological mechanisms responsible for this transport process. Previous studies on embryonic and larval Antarctic echinoderms show that amino acid uptake could provide an important supplement of metabolic substrates. In the present study, partial cDNA sequences of 11 putative amino acid transporter genes were isolated from six species of Antarctic echinoderms including the Antarctic sea stars Acodontaster hodgsoni, Diplasterias brucei, Odontaster meridionalis, Odontaster validus, and Perknaster fuscus, and the Antarctic sea urchin Sterechinus neumayeri. Conserved domains of cDNA-deduced amino acid sequences characterized these genes as being members of a family of amino acid transporters (solute carrier family 6). Expression of these genes was detected throughout embryonic and larval development of two species that have contrasting developmental modes (A. hodgsoni: lecithotrophic; O. meridionalis: planktotrophic). In all six species studied, the expression of amino acid transporter genes was detected in tube feet and digestive organs of adult animals, demonstrating that members of a single amino acid transporter gene family are expressed during the entire life history of a marine invertebrate. The identification of these genes is an important step toward developing a mechanistic understanding of amino acid transport capacities in Antarctic marine invertebrates.     

Evolutionary reorganizations of ontogenesis in ascidians of the genus Molgula

The data on comparative, experimental, and molecular embryology of ascidians (genus Molgula) published during the last 15 years have been reviewed. Some representatives of this genus evolved from development with a tailed larva (tadpole) to direct development associated with the loss of larval structures, such as tail, notochord, sensory organs, and differentiated muscles. The data on evolutionary reorganizations of ontogenesis in ascidians of the genus Molgula have been compared with those in sea urchins, anuran amphibians, and some other organisms.     

Windows of the brain: towards a developmental biology of circumventricular and other neurohemal organs

We review the anatomical and functional features of circumventricular organs in vertebrates and their homologous neurohemal organs in invertebrates. Focusing on cyclostomes (lamprey) and urochordates (ascidians), we discuss the evolutionary origin of these organs as a function of their cell type specification and morphogenesis.     

The biochemical composition of krill, Euphausia superba Dana,from South Georgia

Krill, Euphausia superba Dana, sampled from waters around South Georgia in 1978 contained 10–11% protein, 2–6% lipid, 0.3–0.6% carbohydrate, 2% chitin, and 3–4% mineral ash (all mean values, % fresh weight).Lipid content varied greatly with sexual maturity: males contained 2–4% lipid, immature animals 4% (both increasing to 5–6% later in the season) and mature females 5–6% (although some contained as much as 9%). Gravid females lost ≈60% of their lipid at spawning, and a biochemical estimate of fecundity gave values in the range 7000 to 15 000.The major lipid classes were phospholipid, triacylglyceropl, and free sterol, and there was 1–2% wax ester. The mean pigment content was 21.5 μg/g fresh weight. Triacylglycerol fatty acids were low in polyenoic acids and contained up to 4% phytanic acid; compositions were variable and showed the probable influence of dietary input. Phospholipids were rich in polyenoic acids, especially 20 : 5ω3 and 22 : 6ω3, and usually had 18 : 1ω7 > 18 : 1ω9. Ovarian triacylglycerol contained almost no polyenoic acids, but ovarian phospholipid was fairly unsaturated.These results are discussed in relation to the Antarctic environment, and compared with the results of previous work on caridean decapods.     

Effect of the excretory-secretory products of some marine invertebrates on byssus production of the blue mussel <Emphasis Type="Italic">Mytilus edulis</Emphasis> (Bivalvia: Mytilidae)

Under laboratory conditions, we investigated byssus production in the blue mussel Mytilus edulis, as affected by the excretory-secretory products (ESPs) of the mussel itself and some marine invertebrates: the predatory starfish Asterias rubens, and organisms competing with mussels in White Sea fouling communities—a bivalve Hiatella arctica, the solitary ascidians Styela rustica and Molgula citrine, and a sponge Halichondria panicea. The number of attachment disks produced by a mussel per day and the thickness of byssal threads were estimated. Excretory-secretory products of H. arctica and M. citrine had no effect on the number of attachment disks, while ESPs of S. rustica, H. panacea and A. rubens stimulated mussels to produce attachment plaques. The activity of the mussel was slightly increased at low levels of its own ESPs in seawater. The thickness of byssal threads decreased with an increase in the ESPs of mussels in seawater, but it increased in experiments with the ESPs of any other species tested.     

Fatty acid and lipid analysis of the house cricket,Acheta domesticus

The fatty acid content and composition of the house cricket Acheta domesticus have been investigated in entire insects at different developmental stages and in selected organs of male and female adults. We have also determined the fatty acid composition of the various lipid classes within extracts of the organs of adult female insects. Fatty acids were analysed by capillary gas chromatography or mass spectrometry as their methyl esters (FAMEs) after direct transesterification of insect material or separated lipid classes.The major esterified fatty acids in all extracts were palmitate (C_16:0), stearate (C_18:0), oleate (C_18:1) and linoleate (C_18:2). Levels of esterified fatty acid varied considerably between organs but the fatty acid compositions showed only small variations. The levels of polyunsaturated fatty acids of the C₁₈ series were considerably higher in phospholipid fractions than in other lipid classes. Triacylglycerols formed the major lipid class in ovaries, fat-body and newly-laid eggs, whereas diacylglycerols and phospholipid predominate in the haemolymph. Triacylglycerols, phospholipids, diacylglycerols and free fatty acids were all found in significant amounts in the gut tissue.     

Unusual Symbiotic Cyanobacteria Association in the Genetically Diverse Intertidal Marine Sponge Hymeniacidon perlevis (Demospongiae,Halichondrida)

Cyanobacteria represent one of the most common members of the sponge-associated bacterial community and are abundant symbionts of coral reef ecosystems. In this study we used Transmission Electron Microscopy (TEM) and molecular techniques (16S rRNA gene marker) to characterize the spatial distribution of cyanobionts in the widely dispersed marine intertidal sponge Hymeniacidon perlevis along the coast of Portugal (Atlantic Ocean). We described new sponge associated cyanobacterial morphotypes (Xenococcus-like) and we further observed Acaryochloris sp. as a sponge symbiont, previously only reported in association with ascidians. Besides these two unique cyanobacteria, H. perlevis predominantly harbored Synechococcus sp. and uncultured marine cyanobacteria. Our study supports the hypothesis that the community of sponge cyanobionts varies irrespective of the geographical location and is likely influenced by seasonal fluctuations. The observed multiple cyanobacterial association among sponges of the same host species over a large distance may be attributed to horizontal transfer of symbionts. This may explain the absence of a co-evolutionary pattern between the sponge host and its symbionts. Finally, in spite of the short geographic sampling distance covered, we observed an unexpected high intra-specific genetic diversity in H. perlevis using the mitochondrial genes ATP6 (π = 0.00177), COI (π = 0.00241) and intergenic spacer SP1 (π = 0.00277) relative to the levels of genetic variation of marine sponges elsewhere. Our study suggests that genotypic variation among the sponge host H. perlevis and the associated symbiotic cyanobacteria diversity may be larger than previously recognized.     

Microbial epibionts of the colonial ascidians Didemnum galacteum and Cystodytes sp.

Symbiosis with microorganisms has been well documented for many marine invertebrate taxa. However, knowledge of the diversity of microorganisms associated with ascidians is still limited. This study assessed the microbial epibionts of Didemnum galacteum and Cystodytes sp., two ascidian species collected from the western coast of Ceará state (Brazil), at Dois Coqueiros beach and the port of Pecém, respectively. The microbiota were examined using optical microscopy, followed by subsequent analysis of fingerprinting profiles obtained by denaturing gradient gel electrophoresis (DGGE) and 16S rRNA clone libraries. The microscopy analysis showed for both ascidians a community comprising cyanobacteria, mainly Prochloron-like species, and diatoms. The DGGE results indicated that D. galacteum hosts a more diverse microbiota when compared to Cystodytes sp. The same analysis also suggested that the diversity of the seawater microbiota was higher than the diversity of the ascidian-associated microbiota. The analysis of the 16S rRNA clone libraries revealed the dominance of Proteobacteria symbionts associated with both ascidians, with Alphaproteobacteria as the major component in D. galacteum and Gammaproteobacteria the major component in Cystodytes sp. The analysis of the clone libraries also revealed the presence of other taxa such as Bacteroidetes, Planctomycetes, Actinobacteria, Cyanobacteria, and uncultured bacteria in D. galacteum, but not in Cystodytes sp. Among the bacteria found to be exclusively associated with the ascidians, none were shared by the two studied hosts. The combined results point to a diverse microbiota associated with the external surface of the ascidians, with a mixed composition including organisms typically found in the surrounding seawater, but also a more specific set of taxa.     

Effects of intrinsic and extrinsic factors on the diet of Bathyraja macloviana,a benthophagous skate

The effects of intrinsic (sex, maturity stage and body size) and extrinsic (depth and region) factors on the diet of Bathyraja macloviana, in the south‐west Atlantic Ocean, were evaluated using a multiple‐hypothesis modelling approach. Bathyraja macloviana fed mainly on polychaetes followed by amphipods, isopods and decapods. Effects of intrinsic and extrinsic factors on diet composition of this species were found. The consumption of polychaetes had a humped relationship with total length (L_T), and isopods and decapods increased with increasing L_T. Immature individuals preyed on amphipods more heavily than mature individuals. Furthermore, region and depth had an important effect on the consumption of isopods, decapods and amphipods. Such ontogenetic changes and spatial patterns may provide insights into understanding the regulatory mechanisms of marine communities.     

Marine invertebrates,model organisms,and the modern synthesis: epistemic values,evo-devo,and exclusion

A central reason that undergirds the significance of evo-devo is the claim that development was left out of the Modern synthesis. This claim turns out to be quite complicated, both in terms of whether development was genuinely excluded and how to understand the different kinds of embryological research that might have contributed. The present paper reevaluates this central claim by focusing on the practice of model organism choice. Through a survey of examples utilized in the literature of the Modern synthesis, I identify a previously overlooked feature: exclusion of research on marine invertebrates. Understanding the import of this pattern requires interpreting it in terms of two epistemic values operating in biological research: theoretical generality and explanatory completeness. In tandem, these values clarify and enhance the significance of this exclusion. The absence of marine invertebrates implied both a lack of generality in the resulting theory and a lack of completeness with respect to particular evolutionary problems, such as evolvability and the origin of novelty. These problems were salient to embryological researchers aware of the variation and diversity of larval forms in marine invertebrates. In closing, I apply this analysis to model organism choice in evo-devo and discuss its relevance for an extended evolutionary synthesis.

Genetic variability in a temperate intertidal Phoronid,Phoronopsis viridis

The Phoronida are a coelomate phylum consisting of only two genera and about 12–15 described species. Phoronids probably represent the common ancestral stock of all lophophorates, and may be the most primitive living deuterostomes. Using the techniques of starch gel electrophoresis, we have studied genetic variation at 39 loci in 120 individuals of Phoronopsis viridis collected in Bodega Harbor, Bodega Bay, California. Allelic variation was found at 27 (69.2%) loci. If a locus is considered polymorphic when the frequency of the most common allele is no greater than 0.99, the proportion of polymorphic loci in the total sample is 48.7%. The average number of alleles per locus is 2.23. The expected frequency of heterozygous loci per individual on the assumption of Hardy-Weinberg equilibrium is 9.4%. There is evidence of inbreeding; the mean value of F, Wright's fixation index, is 0.21±0.02. Genetic variability in P. viridis is intermediate among marine invertebrates. The tropical clam, Tridacna maxima, has on the average 20.2% heterozygous loci per individual. At the other extreme, a brachiopod from Antarctica, Liothyrella notorcadensis, has an average of 3.9% heterozygous loci per individual. Among marine invertebrates, there seems to be a gradient of decreasing genetic variability from low to high latitudes, which may reflect their different adaptive strategies.     

Thermotropic behavior of sphingophospholipids of marine invertebrates

Thermotropic behavior of total fraction of sphingomyelin (SM) and its forms, sphingomyelin that contains acyl residues of normal fatty acids (SMN) and sphingomyelin that is Nacylated predominantly with hydroxy acids (SMH) as well as of ceramideaminoethylphosphonate (CAEP) has been studied by the method of differential scanning microcalorimetry. It was shown that chromatographically pure anhydrous sphingophospholipids isolated from different species of marine invertebrates have no phasic transitions in the entire temperature interval of scanning, from-100 to 100°C, whereas partially hydrated samples or mixtures of sphingophospholipids with glycerophospholipids (phosphatidylcholine or phosphatidylethanolamine isolated from corresponding marine invertebrates had phasic transitions in a large temperature range with thermoabsorption maxima in the areas of -40–20°C and 20–80°C. It is suggested that sphingophospholipids, as compared to marine invertebrate glycerophospholipids, have a much lower capability for self-organization, and to form regular supramolecular sphingophospholipid structures both in artificial systems and in biomembranes, such orientants as glycerophospholipids and water are necessary. Possible causes of an unusual behavior of sphingophospholipids of marine invertebrates as compared to glycerophospholipids are discussed.