Ascidian Halocynthia Aurantium Research Articles

Animal Cellulose with Hierarchical Structure Isolated from Halocynthia aurantium Tunic as the Basis for High-Performance Pressure-Resistant Nanofiltration Membrane.

The structure and transport properties of the new Cellokon-AKH membrane based on animal cellulose obtained from tunic of ascidian Halocynthia aurantium were studied. The results of scanning electron microscopy (SEM), FTIR spectroscopy, and the X-ray diffraction data revealed significant differences in the structure and morphology of upper and lower surfaces of this layered film membrane based on animal cellulose. It was shown that the membrane surface is a network of intertwined cellulose fibers, with both denser and looser areas present on the lower surface compared to the completely uniform morphology of the main part of the upper surface. The hierarchical structure of tunicin-based outgrowths evenly distributed over the upper surface was determined and analyzed. The 3D visual representation of the surface structure was performed with the surface reconstruction technique using scanning electron microscope images. A surface model was calculated from the aligned images based on the photogrammetric approach. The transport properties of samples with different prehistory with respect to ethanol, water, and their mixtures of different compositions were studied depending on the pressure. Representing an alcohol-containing gel film in its original state, as solvents are removed, the membrane transforms into a low-permeability fibrillary organized selective film. The obtained results confirmed the possibility of using Cellokon-AKH (dried form) for the filtration of substances with a molecular weight of more than 600 Da in various media. Further study of this new material will allow to get closer to understanding the structure of the studied seabed inhabitants and to use these natural resources more efficiently.

Gonadal Changes during the Annual Reproductive Cycle of the Ascidian Halocynthia aurantium (Pallas).

The ascidian Halocynthia aurantium (sea peach), a marine invertebrate, belongs to the same genus of the phylum Chordata along with the ascidian Halocynthia roretzi (sea pineapple), which is one of the model animals in the field of developmental biology. The characteristics of development and reproduction of H. aurantium are not yet known in detail. In order to find out the spawning period of H. aurantium, we investigated development of the gonads during the annual reproductive cycle. Testis and ovary were both in the bisexual gonads (ovotestes) of H. aurantium, which is a hermaphrodite like H. roretzi. In H. aurantium, the right gonad was longer and slightly larger than the left gonad throughout the year. In each gonad, the number of the testis gonoducts was slightly higher than that of the ovary gonoducts. These features were similarly observed in H. roretzi. However, the number of the testis gonoducts and the ovary gonoducts in each gonad of H. aurantium was about half that of H. roretzi. The gonads of H. aurantium contracted during the winter and summer seasons. The gonads decreased to the smallest size around February, and then started to increase again in March. The gonads were most developed in September of the year. Therefore, it is estimated that the spawning of H. aurantium begins around this period.

Structure and bioactivity of sulfated α-D-mannan from marine bacterium Halomonas halocynthiae KMM 1376T

Halomonas halocynthiae KMM 1376T is a Gram-negative bacterium that has been isolated from gill tissue of the ascidian Halocynthia aurantium. Mild acid hydrolysis of the lipopolysaccharide of H. halocynthiae KMM 1376T afforded an O-polysaccharide, which was studied by sugar analysis and NMR spectroscopy. The following structure of the O-polysaccharide presented as sulfated α-D-mannan was established: →2)-α-D-Manp3,6S-(1→3)-α-D-Manp2Ac(∼71%)6S-(1→3)-α-D-Manp-(1→. Study of biological activity has shown that sulfated α-D-mannan can specifically reduce the cell viability and colony formation of the human breast adenocarcinoma MDA-MB-231 cells in a concentration-dependent manner. In addition, polysaccharide inhibits epidermal growth factor induced neoplastic cell transformation in mouse epidermal JB6 Cl41 cells.

Amino Acids and Related Compounds of the Ascidian Halocynthia aurantium from the Sea of Japan

The overall chemical composition and contents of free (FAA) and bound amino acids and related compounds from various parts of the ascidian Halocynthia aurantium from the Sea of Japan were studied. The amounts of FAA and related nitrogenous compounds were rather high in all parts. The 42 total compounds were dominated by taurine, the absolute content of which was especially high in tunic, exceeding those in mantle and total organs by 1.6 and 2.17 times, respectively. A total of 18 amino acids were identified, eight of which were essential and 10 of which, non-essential. Total internal organs had the highest content of essential amino acids (50.61%); tunic, the lowest (35.01%). Aspartic acid was the dominant non-essential amino acid in all parts (5.84–10.16%), especially in tunic.

The distribution of macrobenthic epifauna in the Far Eastern Marine Reserve based on remote underwater video data

The spatial distribution of epifauna in the Far Eastern Marine Reserve was examined using a remotely operated vehicle. The abundance and distribution patterns of the sea stars Patiria pectinifera, Distolasterias nipon, and Asterias amurensis, as well as those of brittle stars, the black sea cucumber Cucumaria japonica, the sea urchin Strongylocentrotus intermedius, the ascidian Halocynthia aurantium, hermit crabs, and the Japanese scallop Mizuhopecten yessoensis were determined in the South Section of the Reserve. The average biomass of five dominant epifaunal species ranged from 51.0 to 87.4% of the average biomass of the softbottom communities.

Dynamics of hemocyte subsets from ascidian Halocynthia aurantium in response to tissue damage: a comparative analysis of flow cytometry vs confocal microscopy data

The current study was aimed at investigating the dynamics of circulatory ascidian hemocytesubsets from Halocynthia aurantium in response to tunic damage. By using flow cytometry and confocal microscopy, it was demonstrated that the relative amount of hemoblasts and hyaline amebocytes was increased 24 h after cutting ascidian tunic and subjacent muscle layer. By applying a broad panel of fluorescently labeled monoclonal antibodies against human adhesion molecules expressed by lymphoid and stem cells both assays allowed to detect two cross-reactive epitopes (CD54 and CD90) on the surface of ascidian hemocytes. Upon that, the expression of CD54-like epitope was found to be downregulated on ascidian cells after tissue damage, whereas binding to CD90-like epitope was upregulated in all examined cell subsets.

Application of flow cytometry for the analysis of circulating hemocyte populations in the ascidian Halocynthia aurantium (Pallas, 1787)

This study addresses the potentialities of flow cytometry in analyzing the composition of circulating hemocyte populations in the ascidian Halocynthia aurantium (Pallas, 1787) both using monoclonal antibodies (mAbs) against some human leukocyte conservative adhesion molecules and without mAbs. Flow cytometry, based on the assessment of forward and side scattering revealed five hemocyte populations. From the wide panel of antibodies against human leukocyte adhesion molecules (CD15, CD29, CD34, CD54, CD62L, CD62P, CD90, CD94, CD117, CD 166), only two mAbs (against CD54, CD90) displayed cross-reactivity with the H. aurantium hemocyte surface antigens. Distribution patterns of these antigens across the hemocyte populations have been analyzed.

Fouling Communities of Hydrotechnical Constructions in Nakhodka Bay (Sea of Japan)

The fouling of mooring facilities in Nakhodka Bay, Sea of Japan, has been studied. The main fouling communities have been distinguished dominated by green algae Enteromorpha linza and Ulva fenestrata, brown algae Laminaria japonica and Costaria costata, a hydroid Obelia longissima, a polychaete Pseudopotamilla occelata, cirripede barnacles Balanus crenatus and Semibalanus cariosus, a bivalve mollusk Mytilus trossulus, and an ascidian Halocynthia aurantium. The naturalization of some species-invaders in the fouling of mooring facilities in Nakhodka Bay has been registered, namely hydroids Laomedea flexuosa and Clytia languida, a polychaete Pseudopotamilla occelata, and a bryozoan Bowerbankia gracilis.

Halomonas halocynthiae sp. nov., isolated from the marine ascidian Halocynthia aurantium.

The marine bacterium strain KMM 1376T was isolated from gill tissue of the ascidian Halocynthia aurantium, an inhabitant of the coastal waters of the Sea of Japan. Strain KMM 1376T is an aerobic, gram-negative, non-motile, encapsulated, non-pigmented, slightly halophilic bacterium that is characterized by fimbria-like structures, growth in 0.5-15% NaCl at 7-35 degrees C and absence of acid production from many carbohydrates. The DNA G+C content is 54 mol%. The main fatty acids are C16:0, C16.1omega7c and C18:1omega9c. Comparative 16S rDNA sequence analysis of strain KMM 1376T revealed 92.7-95.3% sequence similarity to members of Halomonas. Based on phenotypic and phylogenetic characteristics, it is proposed that the novel isolate be classified as Halomonas halocynthiae sp. nov., with the type strain KMM 1376T (= DSM 14573T).

Thermotropic behavior of major phospholipids from marine invertebrates: changes with warm-acclimation and seasonal acclimatization

The crystal–liquid crystal–isotropic melt phase transitions of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from muscle tissue of five species (actinia Metridium senile fimbriatum, mussel Crenomytilus grayanus, sea-urchin Strongylocentrotus intermedius, starfish Distolasterias nipon and the ascidian Halocynthia aurantium) of marine invertebrates, collected in winter at 0 °C and then acclimated to 18.5 °C for 5 days, were studied by differential scanning calorimetry and polarising microscopy. To elevate temperature from 0 to 18.5 °C, we used the rate of 4.5 °C/h. Although phase transitions of both phospholipids from animals collected in summer occurred already at temperatures below −1.7 oC (minimal temperature of seawater in winter), compensatory mechanisms resulted in a decrease by 29–43 oC in the phase transition temperature of PE in winter. Thermotropic behavior of PCs changed in various trends. However, the total heat of their phase transitions always decreased in winter compared with summer. For all species, except the mussel, the time of warm-acclimation was insufficient to adjust the thermotropic behavior of either phospholipid. Nevertheless, the unsaturation index decreased to achieve summer values, due primarily to decreased proportions of eicosapentaenate and docosahexaenate. The accumulation of arachidonate, during warm-acclimation, might be connected to the signalling properties of n-6 eicosanoids. Absence of effective homeoviscous mechanisms suggests that most of the studied marine invertebrates have very limited capacity to survive an acute temperature elevation, e.g. at the appearance of thermal currents.

Characterization of surfactin-like cyclic depsipeptides synthesized by Bacillus pumilus from ascidian Halocynthia aurantium.

A marine bacterium (KMM 1364), identified as Bacillus pumilus, was isolated from the surface of ascidian Halocynthia aurantium. Structural analysis revealed that the strain KMM 1364 produced a mixture of lipopeptide surfactin analogs with major components with molecular masses of 1035, 1049, 1063, and 1077. The variation in molecular weight represents changes in the number of methylene groups in the lipid and/or peptide portions of the compounds. Structurally, these lipopeptides differ from surfactin in the substitution of the valine residue in position 4 by leucine, and have been isolated as two carboxy-terminal variants, with valine or isoleucine in position 7. As constituents of the lipophilic part of the peptides, only beta-hydroxy-C(15)-, beta-hydroxy-C(16)-, and a high amount of beta-hydroxy-C(17) fatty acid were determined.

Seasonal changes in thermotropic behavior of phosphatidylcholine and phosphatidylethanolamine in different organs of the ascidian Halocynthia aurantium

Differential scanning calorimetry and polarising microscopy were used to investigate the crystal–liquid crystal–isotropic melt phase transitions of phosphatidylcholine (PC), and phosphatidylethanolamine (PE), isolated from muscles, gill pouches, gonads and digestive glands of Halocynthia aurantium, collected in summer and winter. We also analyzed the fatty chain composition of these phospholipids. In summer, the crystalline to liquid crystalline phase transitions of PC and PE from different organs were more co-operative than in winter. Their peak maximum temperatures were close and temperature ranges overlapped for summer samples. Peak maximum temperatures of winter samples decreased sharply, by 18–27°C for PC and by 10–44°C for PE, respectively, depending on the organ. Total heat changes of transitions also decreased. Thermograms were completely located at temperatures below −1.7°C (minimal temperature of seawater in winter). In contrast to summer samples, peak maximum temperatures for PC and PE in winter differed significantly, (by 14–30°C depending on organ), while the temperature ranges of their transitions still showed considerable overlap. Simultaneously, the temperature ranges of the liquid crystalline to isotropic phase transitions decreased. The main reason for changes in thermotropic behavior of phospholipids seems to be the decrease of saturated/unsaturated ratios. The existence of stable and thermoadaptative labile phospholipid pools in the membrane structure is proposed. The relationship of these transitions to low- and high-temperature adaptation is discussed.

Taxonomic Composition and Biological Activity of Microorganisms Associated with a Marine Ascidian Halocynthia aurantium

The taxonomy and biological activity of 176 heterotrophic microorganisms associated with the ascidian Halocynthia aurantiumfrom the coastal waters of Peter the Great Bay (Sea of Japan) were studied. In the microbial community, bacteria of the genera Pseudoalteromonas(38% of all strains studied) and Bacillus(25%) prevailed and showed high biological activity. Bacteria of Pseudoalteromonaswere capable of extracellular hydrolases production and exhibited high antibiotic and antimicrobial properties. Five Pseudoalteromonasstrains were capable of restriction enzyme production. A significant proportion of the pseudoalteromonads inhibited growth ofProteus vulgarisand Candida albicans(81 and 84%, respectively). Spore-forming bacteria of Bacilluswere capable of chitin hydrolysis and extracellular inducible RNAses production (23%). They were active against Staphylococcus aureusand Bacillus subtilis(39 and 23%, respectively). Bacillus pumilusstrain KMM 1364 showed hemolytic activity and antagonistic properties against S. aureusand was found to produce surface active glycolipids and surfactinlike cyclic depsipeptides.

The chemical and enzymatic analyses of the tunic of the ascidian Halocynthia aurantium (pallas)

1. 1. Analyses of tunic of Halocynthia reveal that it is 50 per cent carbohydrate, 50 per cent protein, and that it contains hexosamine but no hydroxyproline. 2. 2. Carbohydrate component of tunic shows limited susceptibility to cellulase, is not dispersed by Schweitzer's reagent, has a higher oxygen and lower hydrogen composition than cellulose and is at least 73 per cent glucose. 3. 3. Tunic is not susceptible to chitinase, hyaluronidase or cellulase, but after pronase digestion and phosphoric acid swelling will release 19 per cent of its weight as glucose upon cellulase digestion. 4. 4. Resistance of tunic serine and glucosamine to pronase digestion indicates their possible involvement in the protein-polysaccharide linkage.