ISSN : 1225-3480
Three marine gastropod species were collected in 1988 to 2019 years from the Jeju island waters of Korea. They were identified as Capulus japonicas A. Adams, 1861, Guraleus himerodes (Melvill & Standen, 1896), and Turridrupa bijubata (Reeve, 1843) that come out into the unrecorded species in Korea. As a result, Korean Capuruidae was nine species of seven genera, the Mangeliidae was 21 species of 13 genera, and the Turridae was six species of three genera.
This study investigated the effect of astaxanthin, synthesized from a marine bacterium (Paracoccus haeundaensis), combined with a culture solution of Lactobacillus (Lactobacillus helveticus) on the growth and physiological responses of the abalone Haliotis discus hannai. The presence of astaxanthin in feed did affect the survival, whereas 100 ppm astaxanthin in feed positively affected the growth, of H. discus hannai. These results indicate that the optimal concentration of astaxanthin in feed has a positive effect on the growth of H. discus hannai, and Lactobacillus in feed has no effect on animal growth. Abalone treated with 100 ppm astaxanthin showed significantly lower glucose levels and superoxide dismutase and lysozyme activities in hemolymph compared with other treatments (p < 0.05). Therefore, the optimal level of astaxanthin in feed may have a positive effect on physiological homeostasis in H. discus hannai.
The little-cone limpet Patelloida conulus (Dunker, 1861) is a member of the Lottiidae, occurring on sandy and muddy tidal flats in the intertidal zone, and is found living symbiotically on shells of mud snails, which often occurs in a high density in sandy and muddy intertidal areas. In this study, we first report association of the little-cone limpets with mud snails from an intertidal sandy beach at Sungsan on the northeast coast of Jeju Island. At the upper intertidal area, the common mud snail Batillaria attramentaria (G. B. Sowerby I, 1855) occurred at a high density, and P. conulus was found on the shell surface. Shell height of the little-cone limpet ranged from 2.6 to 6.6 mm (N = 7), and the host snail carried one P. conulus on its shell in most cases. The little-cone limpet and the mud snail association has been regarded as being restricted to the Batillariidae, while we observed for the first time the occurrence of P. conulus on the cerithiid snail Rhincoclavis kochi (Philippi, 1848).
Metallothionein (MT) plays an important role in protecting cells from harmful substances. MT is a protein with less than seven kDa with large amounts of cysteine residues, which have been studied as a phylogenetic biomarker with unique patterns not only in vertebrates but also in Mollusca. Panopea japonica is a giant clam that lives on the coast of the East Sea in Korea. Nevertheless, little research has been done on the genetic resources of P. japonica, and the amount of genetic information registered in the NCBI is very limited. In this study, a metallothionein sequence consisting of 74 amino acids with 222 bp nucleotide was obtained from the transcriptome data by using the GS FLX 454 platform. In Silico analysis of PjMT gene was conducted with ClustalX and MEGAX programs. With the previously reported Mollusca MT data, we verified the PjMT sequence as a potential candidate for molecular marker, and also confirmed that PjMT was clustered in Myoida order.
Metallothionein (MT) is a metal-binding protein with a small molecular weight that can be induced by factors such as metal ions and chemicals, and is widely present in various organisms. The high cysteine content of MT contributes to the regulation of intracellular metal concentration, detoxification of heavy metals, and it may be induced due to the environment exposed to heavy metals or oxidation stress. MT has been consistently studied as a taxonomic biomarker for various species, including mollusks. Aegista quelpartensis, a native species of Korea, has habitat in Jeju and Jindo island. DNAseq and transcriptome information is registered with NCBI's SRA, but no molecular phylogenetic studies have been conducted. RNA sequencing was performed using Illumina Hiseq 2500 to find the genetic information of A. quelpartensis. The unigene obtained through the de novo assembly was annotated according to the PANM database using the BLAST program, and the MT sequence consisting of 288 bp coding region and 96 amino acid residues was extracted. The bioinformatic analysis verified that A. quelpartensis was grouped in the Stylommatophora clad using the ClustalX and MEGA7 programs. This study confirmed the phylogenetic location of A. quelpartensis and the MT gene is sufficient gene that can be used in phylogenetic studies on Mollusca.
Changes in seawater temperature that occur during the changing of the seasons are a serious challenge faced by scallop aquaculture farms. In this study, we investigated the physiological stress responses of bay scallop Argopecten irradians, to increases and decreases in water temperature. We measured the changes in the levels of expression of copper- and zinc-containing superoxide dismutase (Cu/ZnSOD), and heat shock protein (HSP) 90, as well as the concentrations of lipid peroxide (LPO) in tissues of bay scallops exposed to thermal stress conditions (low-temperature condition: 17°C → 11°C; high-temperature condition: 17°C → 25°C). The expression levels of Cu/ZnSOD and HSP90 mRNA were temperature-dependent following thermal changes. LPO concentrations increased significantly in response to temperature changes. Additionally, greater Cu/ZnSOD and HSP90 expression levels and LPO concentrations were observed under the high-temperature condition than under the low-temperature condition. The results indicate that low and high water temperature conditions induced oxidative stress in bay scallops, and that this effect was greater at high water temperatures than at low water temperatures. This study provides basic knowledge about thermal stress in bay scallops, and our results may contribute to the management of scallop aquaculture farms.
Arginine kinase (AK) belongs to the phosphagen kinase (PK) super family group of enzyme that has an essential role in maintaining energy homeostasis by catalyzing the re-phosphorylation of ADP. The AK gene is used for phylogenetic analysis in arthropods, mollusks, and Nematoda, and has been reported to branch in the Phylum unit. Satsuma myomphala has been reported as an indigenous species in Northeast Asia, including Korea and Japan. Particularly in Korea, it was registered as an endangered wildlife class 2 in 2017. Therefore, the preservation of species and securing genetic resources became more important. The genetic resources of S. myomphala registered on the NCBI GenBank have only six nucleotides and two proteins registered. The AK sequence was extracted from the RNAseq data which was obtained from Illumina Hiseq 2500 platfrom. After sequencing, de novo assembly and clustering, 103,774 unigenes were generated. Through annotation step by using the PANM database and BLAST program, we obtained AK sequence of 354 amino acid residues containing a 1,062 bp coding region. The AK sequence was verified using the BLAST program in the NCBI nr database, and phylogenetic analysis with the AK sequences of Gastropoda, Bivalvia, and Cephalopoda registered in NCBI was conducted. A phylogenetic dendrogram was generated using the MEGA program, and we confirmed the phylogenetic relationships. In addition, the 2D and 3D structures of the AK gene were predicted.
