Phylogeny of the cuttlefishes (Mollusca: Cephalopoda) based on mitochondrial COI and 16S rRNA gene sequence data

To clarify cuttlefish phylogeny, mitochondrial cytochrome c oxidase subunit I (COI) gene and partial 16S rRNA geneare sequenced for 13 cephalopod species. Phylogenetic trees are constructed, with the neighbor-joining method.Coleoids are divided into two main lineages, Decabrachia and Octobrachia. The monophyly of the order Sepioidea,which includes the families Sepiidae, Sepiolidae and Idiosepiidae , is not supported. From the two families ofSepioidea examined, the Sepiolidae are polyphyletic and are excluded from the order. On the basis of 16S rRNA andamino acid of COI gene sequences data, the two genera (Sepiella and Sepia) from the Sepiidae can be distinguished, butdo not have a visible boundary using COI gene sequences. The reason is explained. This suggests that the 16S rDNAof cephalopods is a precious tool to analyze taxonomic relationships at the genus level, and COI gene is fitter at ahigher taxonomic level (i.e., family).

Regulation of swelling-activated chloride channels in embryonic chick heart cells

Swelling-activated Cl- currents, I(Cl,swell), were measured during hyposmotic shock in white Leghornembryonic chick heart cells using the whole-cell recording of patch-clamp technique. Genistein, an inhibitorof protein tyrosine kinase (PTK), suppressed I(Cl,swell). Under isosmotic condition phorbol 12-myristate 13-acetate (PMA), an activator of PKC, elicited the Cl- current similar to that in hyposmotic solution, whereashyposmotic shock did not elicit I(Cl,swell) in chelerythrine chloride(an inhibitor of PKC)-treated cells. Con-focal microscopy experiments using FITC-phalloidin as a fluorescent label of F-actin showed that the actinnetwork was moved from cortical region of the cell to the center after hyposmotic shock as compared withthe image under isosmotic condition. When the cells were treated with cytochalasin B (CB) or cytochalasinD (CD) under isosmotic condition the disruption of the F-actin integrity was observed, and I(Cl,swell) wasnot elicited. With combination treatment of CB with PMA, hyposmotic solution could not elicited I(Cl,swell).The results suggested that the role of PTK, probably receptor tyrosine kinase, for regulation of I(Cl,swell)appeared to be at upstream site related to the role of F-actin. Then PKC signal pathway was activatedsomehow and finally change in the polymerization state of cytoskeleton led to activate the swelling-activatedCl- channels. These results demonstrate clearly that PTK, PKC and F-actin are important factors for reg-ulation of I(Cl,swell), in embryonic chick heart cells as compared with often controversial results reported indifferent cell types.

The study of antioxidant activities of fucoidan from Laminaria japonica

Two large molecular weight fucoidan fractions F-A and F-B were obtained by water extraction and anion-exchange chromatography and then L-A and L-B with low molecular weight and uronic acid content were prepared by radical process degradation of F-A and F-B. The antioxidant activities of the fucoidan fractions on two oxygen free radicals and Cu2+-induced low-density lipoprotein (LDL) oxidation were studied. The results show that all the fucoidan fractions had excellent scavenging capacities on superoxide radical and hypochlorous acid, except the highly sulfated fraction L-B. In LDL oxidation system, low molecular weight fractions L-A and L-B exhibited great inhibitory effects on LDL oxidation induced by Cu2+, however F-A and F-B had little inhibitory effects in this system due to their large molecular weights. The present results suggest that fucoidan from Laminaria japonica is an excellent natural antioxidant and has great potential for preventing the free radical-mediated diseases.

Morphological Comparison between Chinese Ayu and Japanese Ayu and Establishment of Plecoglossus altivelis chinensis Wu&Shan subsp.nov.

The countable characters of Qingdao, Zhejiang, Liaoning and Japanese Ayu are compared. There are no substan- tial different characters among the former three Ayu, so the comprehensive values of them are taken as representative of Chinese Ayu, which is in turn compared with Japanese Ayu ( Plecoglossus altivelis altivelis and Plecoglossus altivelis ryukyuensis). By the coefficient of difference test, 3 and 4 characters are found to be beyond the subspecies level between Chinese Ayu and nominate subspecies (Plecoglossus altivelis altivelis) and between Chinese Ayu (Plecoglossus altivelis chinensis) and Ryukyus subspecies (Plecoglossus altivelis ryukyuensis), respectively, which shows that they belong to different subspecies. The China mainland Ayu is a new subspecies, Plecoglossus altivelis chinensis Wu & Shan, the establishment of which and its forming causes are discussed.

Effects of exogenous Ca^(2+) on the membrane permeability, MDA and SH group content of Alexandrium sp. LC3 under surfactant stress

The effect of Ca 2+ on the removal of Alexandrium sp. LC3 under HDTMAB stress was investigated. The results showed that the toxic effect of HDTMAB on Alexandrium sp. LC3 was significantly reduced in the presence of Ca 2+, especially under 4 mmol/L of Ca 2+. To understand the underlying mechanism, the SH group and MDA content of the cell membrane and membrane permeability were measured. It was found that the SH content of cell member increased, the MDA content and membrane permeability decreased when Alexandrium sp. was treated with Ca 2+ and HDTMAB complex, compared with using HDTMAB only. The data suggested that Ca 2+ might promote HDTMAB stress resistance of Alexandrium sp. LC3 by reducing the permeability and increasing the stability of cell membrane.

Comparison of Taste Components between Triploid and Diploid Oyster

The main taste components of triploid and diploid oyster (Crassostrea gigas) were compared. Free amino acids, inosine monophosphate, succinate, trimethylamine oxide and betaine in fresh and boiled extractives were analyzed. The protein, lipids, glycogen, moisture and ash, which may affect the flavour, were evaluated. In boiled extractives, the amino acids were 394.1 mg(100 g) -1 in diploid and 183.5 mg(100 g) -1 in triploid. However, in fresh oyster extractives, they were 320.0 mg(100 g) -1 and 147.3 mg(100 g) -1 respectively. The inosine monophosphate in triploid was 44% more than that in diploid, and a little difference existed in the content of trimethylamine oxide between them. The contents of these taste components were the basis for taste flavour pattern determination.

Current status of poly culture and rotation culture in Chinese mariculture industry

The status of polyculture and rotational culture in Chinese marine life is reviewed. Some successful experience is summarized.

Preliminary Study on the Water Drag of Schlegel's Black Rockfish Sebastes schlegeli

Drag forces acting on Schlegel’s black rockfish Sebastes schlegeli were studied. A new drag force transducer was designed and used to measure the water drag on Schlegel’s black rockfish in a vertical recirculating flume tank. Fourteen individuals were investigated, yielding two mean drag coefficients referred to the cross sectional area and volume 2/3 respectively at water velocities ranging from 0.3 to 1.0 m s -1 . The drag coefficients can be used for estimating the drag forces acting on Sebastes schlegeli in water.