Genetic heterogeneity analysis and RAPD marker detection among four forms of Atrina pectinata Linnaeus

Pen shell (Atrina pectinata Linnaeus) can be distinguished into four forms based on the morphololgic characteristics. Genetic similarity, and heterogeneity were analyzed among the four forms by random amplified polymorphic DNA (RAPD) technique using 24 10-nucleotide-long primers. Of these primers, 22 pruners produced well-identifiable RAPD band patterns. Significant differences in RAPD band patterns were revealed among the four forms. A total of 198 polymorphic fragments were scored from 22 pruners. and they are specific for one form, shared by two or three forms. Several pruners, such as S451, S453 S463 S464, S470. S473 and S474, produced abundant band patterns and provided sufficient information for reliable discrimination of the four forms. The average genetic distances and phylogenetic relationships were calculated and analyzed according to the distinguishable fragments. The data indicate that pen shells of form G and form Y are similar not only among individuals within the same form, but also between individuals from the two forms, and that shells of form T and form S are highly divergent. The constructed phylogenetic free matches the average genetic distances. Three clusters were clearly distinguishable, in which two were corresponding to form S and form T respectively and one included forms G and Y. This Study will be benefit to further studies oil the taxonomy and selective breeding of Pinnid species. It is suggested that the four forms of pen shell should be categorized to at least two species taxonomically.

A novel anti-tumor protein extracted from Meretrix meretrix Linnaeus induces cell death by increasing cell permeability and inhibiting tubulin polymerization

Discovery and development of new pharmaceuticals from marine organisms are attracting increasing interest. Several agents derived from marine organisms are under preclinical and clinical evaluation as potential anticancer drugs. We extracted and purified a novel anti-tumor protein from the coelomic fluid of Meretrix meretrix Linnaeus by ammonium sulphate fractionation, ion exchange and hydrophobic interaction chromatography. The molecular weight of the highly purified protein, designated MML, was 40 kDa as determined by SDS-PAGE analysis. MML exhibited significant cytotoxicity to several cancer cell types, including human hepatoma BEL-7402, human breast cancer MCF-7 and human colon cancer HCT116 cells. However, no inhibitory effect was found when treating murine normal fibroblasts NIH3T3 and benign human breast MCF-10A cells with MML. The cell death induced by MML was characterized by cell morphological changes. The induction of apoptosis of BEL-7402 cells by MML was weak by DNA ladder assay. The possible mechanisms of its anti-tumor effect might be the changes in cell membrane permeability and inhibition of tubulin polymerization. MML may be developed as a novel, highly selective and effective anti-cancer drug.

人工诱导贻贝Mytilus edulis Linnaeus幼虫附着变态的研究

许多天然物质和人为的外界生物化学因子对许多无脊椎动物附着变态有诱导作用，这为人工控制无脊椎动物幼虫的附着变态过程提供了重要手段，同时对于幼虫培养，特别是对于经济种类幼虫的培养和育苗，具有重要的意义。本文以青岛贻贝Mytilus edulis Linnaeus为研究对象，于1990年1991年分别就不同的海水离子条件、拟肾上腺素和抗肾上腺素、拟胆碱和抗胆碱类化合物以及促进生物新陈代谢类化合物对贻贝幼虫附着变态的诱导作用进行了研究，结果表明：升高K~+或Ca~++浓度以及降低Mg~++浓度均对贻贝幼虫有附着变态诱导作用。Mg~++浓度降低促进K~+的诱导作用。氨基酸类神经递质GABA和其同系物天冬氨酸、谷氨酸、苷氨酸、β－丙氨酸无明显附着变态诱导作用。短时间内，L－DOPA诱导水平（30％）贻贝幼虫不经过附着而直接变态，只作用于β－受体的拟肾上腺素、多巴胺和异丙肾上腺素诱导50％水平的幼虫变态。作用于α－受体的拟肾上腺素、间羟胺、麻黄碱、去氧肾上腺素、去甲肾上腺素和肾上腺素诱70－90％水平的幼虫变态。阻断β－受体的抗肾上腺素、噻吗心安和心得安无诱导作用。但阻断β－受体的抗肾上腺素、立其丁、酚苄明和妥拉苏林对幼虫附着变态有诱导作用。干扰肾上腺素能神经递质释放的化合物利血平无变态诱导作用，并有致死作用。拟胆碱类分合物苯海过、琥珀酰胆碱和阿托品对贻贝幼虫均有附着变态诱导作用。变态诱导率维持在30％水平。拟胆碱化合物加兰他敏有较高的变态诱导率（56.1% (10~(-3)M, 36h)）。抗胆碱类化合物氯丙嗪无明显诱导作用。调节生物体代谢和机能类化合物甲状腺素、ATP、肌、VitB_6和氨茶碱对贻贝幼虫有显著的附着变诱导作用，变态诱导率分别为：甲状腺素84.6 (10~(-3)M, 36h)；ATP 57.7% (10~(-3)M, 36h)；肌苷74.0% (10~(-3)M, 36h); VitB_6 41.3% (10~(-5)M, 36h)和氨茶碱50.0% (10~(-4)M, 36h)。前列腺素无诱导作用，而氯化可的松有一定诱导作用。去甲肾上腺素和乙酰胆碱对幼虫变态的诱导作用被Na~+通道阻断剂普鲁卡因和利多卡因阻断。但ATP和氨茶碱的诱导作用不被其阻断。这表明去甲肾上腺素和乙酰胆碱对幼虫的附着变态的诱导作用是通过视经传递完成的。而神经传递并没有参与ATP和氨茶碱对幼虫变态的诱导过程。

Linnaeus was right all along: Ulva and Enteromorpha are not distinct genera.

Ulva, one of the first Linnaean genera, was later circumscribed to consist of green seaweeds with distromatic blades, and Enteromorpha Link was established for tubular forms. Although several lines of evidence suggest that these generic constructs are artificial, Ulva and Enteromorpha have been maintained as separate genera. Our aims were to determine phylogenetic relationships among taxa currently attributed to Ulva, Enteromorpha, Umbraulva Bae et I.K. Lee and the monotypic genus Chloropelta C.E. Tanner, and to make any nomenclatural changes justified by our findings. Analyses of nuclear ribosomal internal transcribed spacer DNA (ITS nrDNA) (29 ingroup taxa including the type species of Ulva and Enteromorpha), the chloroplast-encoded rbcL gene (for a subset of taxa) and a combined data set were carried out. All trees had a strongly supported clade consisting of all Ulva, Enteromorpha and Chloropelta species, but Ulva and Enteromorpha were not monophyletic. The recent removal of Umbraulva olivascens (P.J.L. Dangeard) Bae et I.K. Lee from Ulva is supported, although the relationship of the segregate genus Umbraulva to Ulvaria requires further investigation. These results, combined with earlier molecular and culture data, provide strong evidence that Ulva, Enteromorpha and Chloropelta are not distinct evolutionary entities and should not be recognized as separate genera. A comparison of traits for surveyed species revealed few synapomorphies. Because Ulva is the oldest name, Enteromorpha and Chloropelta are here reduced to synonymy with Ulva, and new combinations are made where necessary.

Characterization of polymorphic microsatellites for the periwinkle gastropod, Littorina littorea (Linnaeus, 1758) and their cross-amplification in four congeners

Eight polymorphic microsatellite loci are described for Littorina littorea (Linnaeus, 1758). Data on allelic variation in Irish and Celtic Sea samples are reported. The average number of alleles per locus was 11 (range 4-29), and observed and expected heterozygosities ranged from 6.9 to 84.3% and from 9.4 to 95.2%, respectively. Loci did not deviate from Hardy-Weinberg equilibrium and no linkage disequilibrium between loci pairs was detected. Microsatellites were not highly conserved in the congeners, L. fabalis, L. saxatilis, L. compressa and L. obtusata as evidenced by a low rate of cross-amplification. These microsatellites should prove useful in population genetic studies.

Habitat utilization by juvenile hawksbill turtles (Eretmochelys imbricata, Linnaeus, 1766) around a shallow water coral reef

Contemporary studies of sea turtle diving behaviour are generally based upon sophisticated techniques such as the attachment of time depth recorders. However, if the risks of misinterpretation are to be minimized, it is essential that electronic data are analysed in the light of first-hand observations. To this aim, we set out to make observations of juvenile hawksbill turtles (Eretmochelys imbricata , Linnaeus, 1766) foraging and resting in a shallow water coral reef habitat around the granitic Seychelles (4degrees'S, 55degrees'E). Data were collected from six study sites characterized by a shallow reef plateau (

A test for mucus removal in the chiton Lepidochitona cinerea (Linnaeus, 1767) (Polyplacophora: Chitonida: Ischnochitonidae)

Several methods have been proposed to ‘clean’ the soft tissues of molluscs of mucus, so that the surface cilia can be examined microscopically. We report the first empirical test of the effectiveness of methods for removing mucus in the pallial cavity surface of chitons. Three methods were compared, at several time intervals: the enzyme hyaluronidase, the mucolytic agent N-acetyl cysteine (NAC), and seawater washing via the natural action of cilia in excised tissue. Treatment in NAC for 10 min produced the best results, and we recommend this protocol as a starting point for further investigation on mucus removal in a broader suite of taxa. We present the first description of the pallial surface cilia in the chiton Lepidochitona cinerea. During the course of this study, we also determined that these chitons were frequently infested with a ciliate protozoan parasite, Trichodina sp., which have been historically reported from chitons but never studied in detail. The parasites were absent where antimucus treatments were effective, but their abundance and large size (about 30-mm diameter) in less successful treatments obscured the view of the pallial cavity surface.