Effects of dietary sea squirt (Halocynthia roretzi) on lipid metabolism in rats

The effect of dietary sea squirt ( Halocynthia roretzi) on lipid metabolism in rats was investigated. Rats were fed sea squirt muscle (Experiment 1); sea squirt muscle, defatted sea squirt muscle and its hexane extract (Experiment 2); and whole body sea squirt and its parts as muscle or viscera (Experiment 3). All of the diets contained the same levels of protein (20%) and lipid (7%). In experiment 1, serum total cholesterol (T-Ch), very-low-density lipoprotein plus low-density lipoprotein (VLDL+LDL)-Ch, triglyceride (TG), phospholipid (PL) and nonesterified fatty acid (NEFA) levels were reduced by 20% dietary sea squirt muscle ingestion; steroid excretions into feces were enhanced by the same diet. In experiment 2, serum T-Ch, (VLDL+LDL)-Ch, TG, PL and NEFA levels were significantly reduced and steroid excretions into feces were significantly enhanced by ingestion of the sea squirt muscle hexane extract. Ingestion of defatted sea squirt muscle also reduced these serum lipid levels, but not as much as did that of whole sea squirt muscle. In experiment 3, serum T-Ch and HDL-Ch levels were significantly elevated by the 10% sea squirt viscera ingestion.     

Taxonomic assessment and enzymes production by yeasts isolated from marine and terrestrial Antarctic samples

The aim of the present study was to investigate the taxonomic identity of yeasts isolated from the Antarctic continent and to evaluate their ability to produce enzymes (lipase, protease and xylanase) at low and moderate temperatures. A total of 97 yeast strains were recovered from marine and terrestrial samples collected in the Antarctica. The highest amount of yeast strains was obtained from marine sediments, followed by lichens, ornithogenic soils, sea stars, Salpa sp., algae, sea urchin, sea squirt, stone with lichens, Nacella concinna, sea sponge, sea isopod and sea snail. Data from polyphasic taxonomy revealed the presence of 21 yeast species, distributed in the phylum Ascomycota (n = 8) and Basidiomycota (n = 13). Representatives of encapsulated yeasts, belonging to genera Rhodotorula and Cryptococcus were recovered from 7 different Antarctic samples. Moreover, Candida glaebosa, Cryptococcus victoriae, Meyerozyma (Pichia) guilliermondii, Rhodotorula mucilaginosa and R. laryngis were the most abundant yeast species recovered. This is the first report of the occurrence of some species of yeasts recovered from Antarctic marine invertebrates. Additionally, results from enzymes production at low/moderate temperatures revealed that the Antarctic environment contains metabolically diverse cultivable yeasts, which could be considered as a target for biotechnological applications. Among the evaluated yeasts in the present study 46.39, 37.11 and 14.43 % were able to produce lipase (at 15 °C), xylanase (at 15 °C) and protease (at 25 °C), respectively. The majority of lipolytic, proteolytic and xylanolytic strains were distributed in the phylum Basidiomycota and were mainly recovered from sea stars, lichens, sea urchin and marine sediments.     

New and emerging analytical techniques for marine biotechnology

Marine biotechnology is the industrial, medical or environmental application of biological resources from the sea. Since the marine environment is the most biologically and chemically diverse habitat on the planet, marine biotechnology has, in recent years delivered a growing number of major therapeutic products, industrial and environmental applications and analytical tools. These range from the use of a snail toxin to develop a pain control drug, metabolites from a sea squirt to develop an anti-cancer therapeutic, and marine enzymes to remove bacterial biofilms. In addition, well known and broadly used analytical techniques are derived from marine molecules or enzymes, including green fluorescence protein gene tagging methods and heat resistant polymerases used in the polymerase chain reaction. Advances in bacterial identification, metabolic profiling and physical handling of cells are being revolutionised by techniques such as mass spectrometric analysis of bacterial proteins. Advances in instrumentation and a combination of these physical advances with progress in proteomics and bioinformatics are accelerating our ability to harness biology for commercial gain. Single cell Raman spectroscopy and microfluidics are two emerging techniques which are also discussed elsewhere in this issue. In this review, we provide a brief survey and update of the most powerful and rapidly growing analytical techniques as used in marine biotechnology, together with some promising examples of less well known earlier stage methods which may make a bigger impact in the future.     

Genetic differences between wild and hatchery populations of red sea cucumber (Stichopus japonicus) inferred from microsatellite markers: implications for production and stocking programs design

Red sea cucumber Stichopus japonicus is the most important and valuable commercial sea cucumber species in Korea. Its farming and stock enhancement started in the early 2000s and is still rapid expansion in Korea. Therefore, the analyses of genetic status of wild and hatchery populations are necessary to maintain the genetic diversity of this valuable marine resource. In this study, possible genetic similarity and differences between the wild population and hatchery population in Jeju, Korea were accessed using multiplex assays with eight highly polymorphic microsatellite loci. High levels of polymorphism were observed between the two populations. A total of 93 different alleles were found. Although a considerable loss of unique alleles and relatively high inbreeding coefficient value were observed in the hatchery samples, no statistically significant reductions were found in heterozygosity or allelic diversity in the hatchery population, compared with the wild population. However, significant genetic heterogeneity was found between two populations. These results suggest that genetic drift has probably promoted differentiation between populations, and stocking intensity in wild populations may correlate with loss of genetic integrity. Therefore, the sustainable exploitation plans of the fishery resource should be developed by applying basic genetic principles combined with molecular monitoring. This genetic baseline information of Korean red sea cucumber has important implications for designing of genetically sustainable restocking programs and more efficient conservation management guidelines for these valuable genetic materials.     

Purification and characterization of a sea squirt beta-galactosidase

A beta-galactosidase was extracted from the internal organs of a sea squirt, Styela plicata, and purified 959-fold, with an 18% yield, by successive gel chromatography, anion-exchange chromatography, chromatofocusing, and affinity chromatography on a Con A-Sepharose column. The purified enzyme was fairly homogeneous, as judged on disc PAGE, SDS-PAGE, and gel chromatography on a Sephadex G-200 column. The molecular weight of the enzyme was estimated to be 77,000 and 75,000 by gel chromatography and SDS-PAGE, respectively, and its isoelectric point was determined to be 4.9 by the isoelectric focusing method. The enzyme was substantially stable in the pH range of 3.5 to 7.5, the optimum pH being 4.0. The enzyme was significantly inhibited by 9 mM HgCl2 and 9 mM DFP, while the inhibition by 0.9% PCMB was only 60% at 0 degrees C for 30 min. The purified beta-galactosidase apparently liberated galactose from a sea squirt antigen (H-antigen), two allergenically active glycopeptides (Gp-1 and Gp-2) derived from another sea squirt antigen (Gi-rep), asialo-ovomucoid glycopeptide, asialo-fetuin glycopeptide, GA1, CDH, and an ABEE-derivative (Gal beta 1----3ThrNAc-ABEE) of Gal beta 1----3GalNAc-ol isolated from bovine submaxillary gland mucin.     

Genetic differentiation among populations and color variants of sea cucumbers (Stichopus japonicus) from Korea and China

The Far Eastern sea cucumber, Stichopus japonicus, is a favored food in Eastern Asia, including Korea, Japan, and China. Aquaculture production of this species has increased because of recent declines in natural stocks and government-operated stock release programs are ongoing. Therefore, the analyses of genetic structure in wild and hatchery populations are necessary to maintain the genetic diversity of this valuable marine resource. In addition, given that sea cucumber color affects market price, with the rare, possibly reproductively isolated, red type being the most valuable, an understanding of the genetic structure and diversity in color variation of green and red types is necessary. We analyzed the genetic structure of wild and hatchery-produced green type S. japonicus from Korea and China, and wild red type from Korea using 9 microsatellite makers. The number of alleles per locus ranged from 11 to 29 across all populations. The mean allele numbers of the green types from Korea (10.6) and China (10.1) were similar, but differed slightly from that of the red type (9.1). Pairwise multilocus F(ST) and genetic distance estimations showed no significant differences between the green types from Korea and China, whereas the differences between the green and red types were significant. This was clearly illustrated by a UPGMA dendrogram, in which the two close subclusters of green types were completely separated from the red type. In addition, the allele frequencies of the green and red types were significantly different. Assignment tests correctly assigned 100% (quality index 99.97%) of individuals to their original color types and demonstrated the feasibility of microsatellite analysis for discrimination between color types.     

Genetic and Genomic Toolbox of the Chordate Ciona intestinalis

The experimental malleability and unique phylogenetic position of the sea squirt Ciona intestinalis as part of the sister group to the vertebrates have helped establish these marine chordates as model organisms for the study of developmental genetics and evolution. Here we summarize the tools, techniques, and resources available to the Ciona geneticist, citing examples of studies that employed such strategies in the elucidation of gene function in Ciona. Genetic screens, germline transgenesis, electroporation of plasmid DNA, and microinjection of morpholinos are all routinely employed, and in the near future we expect these to be complemented by targeted mutagenesis, homologous recombination, and RNAi. The genomic resources available will continue to support the design and interpretation of genetic experiments and allow for increasingly sophisticated approaches on a high-throughput, whole-genome scale.     

Molecular evidence from ascidians for the evolutionary origin of vertebrate cranial sensory placodes

Cranial sensory placodes are specialised areas of the head ectoderm of vertebrate embryos that contribute to the formation of the cranial sense organs and associated ganglia. Placodes are often considered a vertebrate innovation, and their evolution has been hypothesised as one key adaptation underlying the evolution of active predation by primitive vertebrates. Here, we review recent molecular evidence pertinent to understanding the evolutionary origin of placodes. The development of vertebrate placodes is regulated by numerous genes, including members of the Pax, Six, Eya, Fox, Phox, Neurogenin and Pou gene families. In the sea squirt Ciona intestinalis (a basal chordate and close relative of the vertebrates), orthologues of these genes are deployed in the development of the oral and atrial siphons, structures used for filter feeding by the sessile adult. Our interpretation of these findings is that vertebrate placodes and sea squirt siphon primordia have evolved from the same patches of specialised ectoderm present in the common ancestor of the chordates.     

Extremely high molecular diversity within the East Asian nematode Caenorhabditis sp. 5

Most relatives of the self-fertilizing hermaphroditic nematode model organism Caenorhabditis elegans reproduce via obligate outbreeding between males and females, which also represents the ancestral mode of reproduction within the genus. However, little is known about the scope of genetic diversity and differentiation within such gonochoristic species, especially those found outside of temperate Europe and North America. It is critical to understand the evolutionary processes operating in these species to provide a framework for deciphering the evolution of hermaphroditism and a baseline for the application of outcrossing Caenorhabditis to problems in evolutionary genetics. Here, we investigate for the first time molecular sequence variation for Caenorhabditis sp. 5, a species found commonly in eastern Asia. We identify enormous levels of standing genetic variation that approach the levels observed in the marine broadcast-spawning sea squirt, Ciona savignyi. Although we document significant isolation by distance, we demonstrate that the high polymorphism within C. sp. 5 is not because of strong differentiation among populations or to the presence of cryptic species. These findings illustrate that molecular population genetic approaches to studying obligately outbreeding species of Caenorhabditis will prove powerful in identifying and characterizing functionally and evolutionarily important features of the genome.     

Glycosaminoglycans from marine sources as therapeutic agents

Glycosaminoglycans (GAGs) in marine animals are different to those of terrestrial organisms, mainly in terms of molecular weight and sulfation. The therapeutic properties of GAGs are related to their ability to interact with proteins, which is very much influenced by sulfation position and patterns. Since currently GAGs cannot be chemically synthesized, they are sourced from natural products, with high intra- but also inter-species variability, in terms of chain length, disaccharide composition and sulfation pattern. Consequently, sulfated GAGs are the most interesting molecules in the marine environment and constitute the focus of the present review. In particular, chondroitin sulfate (CS) appears as the most promising compound. CS-E chains [GlcA-GalNAc(4S,6S)] extracted from squid possess antiviral and anti-metastatic activities and seem to impart signalling properties and improve the mechanical performance of cartilage engineering constructs; Squid CS-E and octopus CS-K [GlcA(3S)-GalNAc(4S)], dermatan sulfate (DS) from sea squirts [-iK units, IdoA(3S)-GalNAc(4S)] and sea urchins [-iE units, IdoA-GalNAc(4S,6S)] and hybrids CS/DS from sharks (-B/iB [GlcA/IdoA(2S)-GalNAc(4S)], -D/iD [GlcA/IdoA(2S)-GalNAc(6S)] and –E/iE units [GlcA/IdoA-GalNAc(4S,6S)]) promote neurite outgrowth and could be valuable materials for nerve regeneration. Also displaying antiviral and anti-metastatic properties, a rare CS with fucosylated branches isolated from sea cucumbers is an anticoagulant and anti-inflammatory agent. In this same line, marine heparin extracted from shrimp and sea squirt has proven anti-inflammatory properties, with the added advantage of decreased risk of bleeding because of its low anticoagulant activity.     

Sugar sequences of allergenically active oligosaccharide alcohols isolated from a large-molecular-size sea squirt antigen termed H-antigen

O-Glycosidically linked oligosaccharide chains were liberated as oligosaccharide alcohols (HPG-beta 2) by beta-elimination treatment from a glycopeptide fraction (HPG, Mr ca. 10(5)) that was isolated from a Pronase digest of a large-size sea squirt antigen termed H-antigen (Mr 10(6)-2 X 10(7)). After HPG-beta 2 was divided into a neutral (HPG-beta 2-N) and an acidic (HPG-beta 2-A) fraction, 11 neutral saccharitols were isolated from HPG-beta 2-N, and their sugar sequences were determined by methylation/GC-MS, FAB-MS, and/or DI/EI-MS. By skin tests specific to patients with sea squirt allergy, it was found that six saccharitols were allergenically active but five were inactive. Furthermore, active saccharitols were all of branched structure containing two nonreducing terminal GalNAc (t-GalNAc) residues, whereas the inactive saccharitols contained one or no t-GalNAc. Since the allergic reaction in skin should depend on the crosslinking of IgE antibodies by certain allergens carrying two or more epitopes, three types of N-acetylgalactosaminyl disaccharide units, GalNAc1----2Fuc1----, GalNAc1----3/4GalNAc1----, and GalNAc1----3/4GlcNAc1----, were nominated as the major components of the allergy-specific epitopes in the active saccharitols. Such multiplicity of the epitope structures might reflect the polyclonality of the specific IgE antibodies.     

Fluorescent Proteins and Their Use in Marine Biosciences,Biotechnology, and Proteomics

This review explores the field of fluorescent proteins (FPs) from the perspective of their marine origins and their applications in marine biotechnology and proteomics. FPs occur in hydrozoan, anthozoan, and copepodan species, and possibly in other metazoan niches as well. Many FPs exhibit unique photophysical and photochemical properties that are the source of exciting research opportunities and technological development. Wild-type FPs can be enhanced by mutagenetic modifications leading to variants with optimized fluorescence and new functionalities. Paradoxically, the benefits from ocean-derived FPs have been realized, first and foremost, for terrestrial organisms. In recent years, however, FPs have also made inroads into aquatic biosciences, primarily as genetically encoded fluorescent fusion tags for optical marking and tracking of proteins, organelles, and cells. Examples of FPs and applications summarized here testify to growing utilization of FP-based platform technologies in basic and applied biology of aquatic organisms. Hydra, sea squirt, zebrafish, striped bass, rainbow trout, salmonids, and various mussels are only a few of numerous instances where FPs have been used to address questions relevant to evolutionary and developmental research and aquaculture.     

Factors influencing return rate and marine residence duration in sea trout populations in Central Norway

Brown trout (Salmo trutta) display extensive plasticity in marine migratory behaviours, with marine migrations considered to be an adaptive strategy which enables sea trout to maximize growth and reproductive potential. However, marine migrations are not without associated costs, including threats posed by ever-increasing salmon lice (Lepeophtheirus salmonis) infestations. In the present study, we used passive integrated transponder technology to characterize variability in sea trout migration behaviour amongst three catchments situated in a region of intensive salmon farming in central Norway. Specifically, we investigate how lice infestation, out-migration date and body size alter sea trout return rate and marine residence duration during the first out-migration to sea from each catchment. Distinct catchment-specific differences in sea trout out-migration size and the number of cohorts were observed, but larger body size did not guarantee the successful return of migrating trout. The marine residence duration of individuals that successfully returned to freshwater was positively correlated with lice infestation risk, suggesting for these individuals the lethal infestation threshold had not been reached. Our results also suggest that sea trout populations from lotic-dominated catchments are potentially at greater risk from size-related threats to their survival encountered during their marine migrations than sea trout from lentic-dominated catchments. The variability in sea trout migratory behaviour amongst catchments observed here emphasizes the challenges fisheries managers face when deciding the best actions to take to protect the anadromous portion of brown trout populations.     

Seeing chordate evolution through the <Emphasis Type="Italic">Ciona</Emphasis>genome sequence

A draft sequence of the compact genome of the sea squirt Ciona intestinalis, a non-vertebrate chordate that diverged very early from other chordates, including vertebrates, illuminates how chordates originated and how vertebrate developmental innovations evolved.     

Novel tetraamines,pentaamines and hexaamines in sea urchin,sea cucumber,sea squirt and bivalves

• 1.1. Polyamines were extracted from the guts and ovaries of the sea urchin Anthocidoris crassispina, and the guts and flesh of the sea cucumber Stichopus japonicus and the sea squirt Halocynthia roretzi, the oyster Crassostrea gigas and the short-necked clam Tapes philippinarum, and analyzed by ion-exchange high-performance liquid chromatography and gas chromatography-mass spectrometry.
• 2.2. Norspermidine and norspermine as well as putrescine, cadaverine, spermidine, spermine and agmatine were the ubiquitous polyamines in these invertebrates. These results suggest the widespread distribution of norspermidine and norspermine in invertebrates.
• 3.3. Thermopentamine, thermohexamine and homothermohexamine were found in the sea urchin. This in the first report on the occurence of thermopentamine and hexaamine in invertebrates.
• 4.4. Homospermidine, canavalmine, aminopropylhomospermidine, homospermine, caldopentamine, homocaldopentamine and aminopropylcanavalmine were found in the sea cucumber. Homospermidine, aminopropylhomospermidine and homospermine were found in the squirt. This is the first report on the occurence of canavalmine, aminopropylhomospermidine, homospermine, homocaldopentamine and aminopropylcanavalmine in invertebrates.

     

基于生态系统管理理论的海域集约利用评价——以河北沿海地级市为例

基于生态系统管理理论,从海洋投入强度、海洋利用强度、海洋经济效益及海洋生态环境质量层面,构建海域集约利用评价的指标体系,运用模糊决策分析理论计算各指标权重,得到河北省沿海地级市2005—2014年的海域集约利用综合指数,并利用聚类分析法及协调度指数对河北省海域集约利用的区域差异特征进行了分析。研究结果表明:2005—2014年河北省海域集约利用综合水平不断提高,除海洋生态环境质量准则层指数呈下降趋势外,海洋投入强度、海洋利用强度、海洋经济效益3个层面指数均呈上升趋势,其中持续增加趋势最明显的是海洋经济效益准则层;河北省沿海三市海域集约利用综合指数及各准则层指数的时序变化特征基本一致,但各区域之间仍体现着不同的变化特点,沧州市海域集约利用程度较高,唐山市海域集约利用经历了由低到高的过程,秦皇岛市海域集约利用的状况整体处于一般水平;河北省及沿海三市海域集约利用总体保持了较高的协调度,但各地区不同时段的变化特征有所不同。