Genetic diversity and population structure of the sea star Asterias amurensis in the northern coast of China

The sea star Asterias amurensis is widely viewed as a severe“marine pest”because of its broad feeding habits.Over the past few decades,A.amurensis undergoes massive and sporadic population outbreaks worldwide,causing extensive economic and ecological losses to the local aquaculture industry and marine ecosystem.Understanding the genetic diversity and population structure of A.amurensis can provide vital information for resource management.By analyzing the polymorphism of the mitochondrial cytochrome C oxidase subunit I(COI)gene and ten simple sequence repeat(SSR)microsatellites markers,the genetic diversity and population structure of A.amurensis of four populations along the northern coast of China was uncovered.A total of 36 haplotypes were identified,and a main haplotype was found in four populations.The Qingdao(QD)population displayed the highest genetic diversity among all the populations.The AMOVA and pairwise F_(st)showed that there was small but statistically significant population differentiation among the four populations,especially between QD and Weihai(WH).Moreover,the principal component analysis(PCA)and admixture analysis showed that several individuals in Yantai(YT)and Dalian(DL)had little genetic association with other individuals.Overall,this study provided useful information of the genetic diversity and population structure of A.amurensis and will contribute to the resource management of A.amurensis in China.

Chemical Constituents from Starfish Asterias rollestoni

Aim To investigate novel bioactive and structural metabolites from marineorganisms. Methods Column chromatography in association with semi-preparative HPLC were used for theisolation of compounds. 1D and 2D NMR, IR, UV, and MS were employed for structure elucidation.Results From the butanol fraction of the 95% EtOH extract of the starfish Asterias rollestoni, a newcompound N^7 -2'-deoxypseudoxanthosine (1), along with sixteen known compounds, 2'-0-methyl-inosine(2), 2'-deoxyinosine (3), 2'-0-methylguanosine (4), inosine (5); thymine (6), uracil (7), thymidine(8), deoxyuridine (9), 2'-0-methyluridine (10), ( ― )-(1S, 3S)-1-methyl-1, 2, 3,4-terrahydro-β-carboline-3-carboxyl-ic acid (11), ( ― )-(1R, 3S)-1-methyl-1, 2, 3,4-tetrahydro-β-carboline-3-carboxylic acid (12) , ( ― )-(3S)- 1, 2, 3,4-tetrahydro-β-carboline-3-carboxylic acid (13), L-tryptophan (14), L-phenylalanine (15), 3-carboxyindole (16), and p-hydroxybenzoic acid (17) , have been isolated. Conclusion Compound 1 is a newnatural product, and compounds 8, 9 and 10 are isolated from natural sources for the first time, andthe known compounds except 14 and 15 are first reported from starfish Asterias rollestoni.

Sulfated Sterols Isolated from Starfish Asterias amurensis Lutken

Aim To study the chemical constituents of starfish Asterias amurensis. Methods The constituents were separated and purified by different chromatographic methods, and their structures were elucidated by MS and NMR. Results Six compounds were isolated from Asterias amurensis Lutken. Their structures were identified as 3β-O-sulfated-cholest-5-en sodium salt （1）, 3β-O-sulfated-6α-ol- pregn-9（ 11 ） -en-20-one sodium salt （ 2 ）, 3β-O-sulfated-6α-ol-cholest-9 （ 11 ） -en-23-one sodium salt （3）, 3β-O-sulfated-6α, 20β-diol-cholest-9 （ 11 ）-en-23-one sodium salt （ 4 ）, 3β-O-sulfated-6α-ol- cholesta-9 （ 11 ）, 20 （ 22 ） -dien-23-one sodium salt （ 5 ）, and 3β-O-sulfated-6ct-ol-ergost-9 （ 11 ） -en-23- one sodium salt （6）. Conclusion Compounds 1 - 6 were obtained from this species for the first time.

Comparison of Lipids in Organs of the Starfish Asterias amurensis Associated with Different Treatments

Lipids were extracted from organs of the starfish Asterias amurens＆ associated with different treatments （raw-control, boiling and heating）, and then analyzed for lipid content, lipid oxidation index, lipid classes and fatty acid composition. Results showed that boiling softened the hard starfish shells, thus facilitating the collection of starfish organs. As compared with raw organs, the boiled organs had lower water content and higher lipid content, possibly due to the loss of water-holding capacity caused by pro- tein denaturation. Both boiling and heating increased the peroxide value （PV）, thiobarbituric acid （TBA） value and carbon value （CV） of lipids. Despite slight increases in the content of complex lipids, associated lipid composition had no substantial variations upon boiling and heating. For simple lipids, the content of 1, 2-diglyceride decreased in boiled and heated organs, with free fatty acids observed on thin layer chromatography （TLC）. However, neither boiling nor heating significantly changed the fatty acid composi- tions of simple or complex lipids in starfish organs, suggesting that these two treatments had no significant effects on complex lipids in starfish organs. Together, our results indicated that boiling of starfish soon after capture facilitated the handling and extraction of useful complex lipids consisting of abundant glucosylceramide and eicosapentaenoic acid （EPA）-bounded phospholipids.

Patterns and Cellular Mechanisms of Arm Regeneration in Adult Starfish Asterias rollestoni Bell

To understand the mechanisms of starfish regeneration, the arms of adult starfish Asterias rollestoni Bell were amputated and their regeneration patterns and cellular mechanisms were studied.It was found that cells in the outer epidermis and inner parietal peritoneum near the end of the stump began to dedifferentiate 4 d after amputation. The dedifferentiated cells in the outer epidermis proliferated,migrated to the wound site and formed a thickened pre-epidermis which would then re-differentiate gradually into ma-ture epidermis.The new parietal peritoneum formed on the coelomic side of wound might be from the curvely elongated parietal peritoneum, resulting from the dedifferentiated and proliferated cells by extension. Afterwards, the proliferated cells made the outer epidermis and inner parietal peritoneum invaginate into the interior dermis and formed blastema-like structures together with induced dedifferentiated dermal cells. Most interestingly, the arm regeneration in A. rollestoni was achieved synchronously by de novo arm-bud formation and growth, and arm-stump elongation. The crucial aspects of arm-bud formation included cell dedifferentiation, proliferation and migration, while those of arm-stump elongation included cell dedifferentiation, proliferation, invagination, and arm-wall-across blastema-like structure formation. The unique pattern and cellular mechanisms of amputated arm regeneration make it easier to understand the rapid regeneration process of adult starfish. This study may lay solid foundations for the research into mo-lecular mechanisms of echinoderm regeneration.

A preliminary study on food consumption, preference and day-night predatory difference of Asterias amurensis on Scapharca broughtonii

In order to study the food consumption, preference and day-night predatorydifference of Asterias amurensis on Scapharca broughtonii, the experiments werecarried out at the temperatures ranging from 16 ℃ to 20 ℃, salinity of 28.2 ± 2.1,dissolved oxygen of 7.5±0.7 mg/L and pH of 8.0 ± 0.3.The results provided basic datafor promoting steady and healthy development of the multiplication and cultivation of S.broughtonii. The results of food consumption suggested that the food intake of starfishincreased with the density of S. broughtonii at all conditions. The food consumption ofstarfish in different sizes on S. broughtonii in the same size had no significant difference(p>0.05), but it was significantly different among S. broughtonii in different sizes. Thestarfish had the highest feeding rate on the smallest S. broughtonii. Our findings alsoverified the positive relation between the weight of food intake of starfish in differentsizes on the density and size of S. broughtonii. The feeding rhythm of starfish onS. broughtonii in different sizes showed a certain day-night difference, higher at nightthan in the day. The maximum food consumption occurred when the size of S.broughtonii became larger. The results showed that 30 ind/m2 was the suitable seabottom sowing density for S. broughtonii. Our data indicated that the ability to avoidpredators and rivals increased as the shell length rose. Based on prey selectivity,bivalves that have a lower commercial value may be used to clear away A. amurensis.

扁玉螺、罗氏海盘车中牛磺酸的HPLC测定

利用高效液相色谱OPA柱前衍生法测定扁玉螺(Nevertia didyma(Roding))肝脏、腹足,罗氏海盘车(Asterias rollestoni Bell)内脏、体壁中牛磺酸的含量。实验结果表明,100g(湿质量)样品中牛磺酸含量分别为535.2、1298.7、60.4、31.7mg。