Ultrastructural Evidence for Temperature-Dependent Ca2+ Release from Fish Sarcoplasmic Reticulum During Rigor Mortis

The release or leakage of ca2+ from the sarcoplasmic reticulum (SR) during rigor mortis of fish muscle was investigated by transmission electron microscopy using pyroantimonate and related biochemical changes. Ca2+ -pyroantimonate deposits were observed in the SR immediately after spiking the fish. At the onset of rigor for fish stored at 0°C, no deposits were found in the SR; however, fish stored for the same period at woe which were still in the pre-rigor state, clearly showed Ca2+ deposits in the SR. In association with the Ca2+ translocation, ATP degraded faster at 0 c than at 10 °C, probably due to enhancement of myofibrillar ATPase activity by the increasing Ca2 + concentrations. Therefore, rapid Ca2+ release from the SR at 0°C seemed to trigger the acceleration of fish rigor mort is at this temperature, analogous to the phenomenon called cold shortening

Genetic diversity of blue-spotted mudskipper (Boleophthalmus boddarti) populations in Gulf of Thailand

Environmental changes and the reduction of habitat can threaten populations of mudskippers, which have a distinct life cycle compared with other fish species. Genetic diversity and structure are crucial information for the conservation plan of this species. The genetic diversity was investigated on the blue-spotted mudskipper, Boleophtalmus boddarti, in the Gulf of Thailand. In total, 178 fish were collected from six locations in the Gulf. Based on the 320 bp sequences of the mitochondrial control region of the 55 haplotypes observed, the most common was in 88 fish from all locations. Total haplotype diversity and nucleotide diversity values (mean ± SD) were h = 0.751 ± 0.036 and π = 0.0069 ± 0.0001, respectively. There was a significant (p = 0.011) difference in π between inner and outer Gulf samples. Although the analysis of molecular variance suggested the absence of genetic structuring within the Gulf, two clear groups of haplotypes were evident in the medianjoining network of haplotypes. Group I included haplotypes from all locations and group II was identified by haplotypes with an additional adenine at the 16078th position based on the mitochondrial genome sequence of B. boddarti (Accession no. KF87427). The results of the nonmetric multidimensional scaling and Bayesian assignment test were indicative of genetic divergence between the inner and outer Gulf, suggesting that despite the high potential for dispersal of planktonic larvae, water currents may act as a physical barrier to gene flow in the study area. The observed signals of population divergence between B. boddarti from the inner and outer Gulf of Thailand may account for the presence of this oceanographical barrier. Mismatch distributions, based on the observed number of differences among haplotype pairs, produced a unimodal distribution with a peak close to the y-axis, suggesting recent demographic expansion. The results could augment future study with baseline information on the maternal genetic variation and structure of the bluespotted mudskipper, B. boddarti, populations in the Gulf of Thailand

Identification and characterization of a matrix protein (PPP-10) in the periostracum of the pearl oyster, Pinctada fucata

AbstractThe periostracum is a layered structure that is formed as a mollusk shell grows. The shell is covered by the periostracum, which consists of organic matrices that prevent decalcification of the shell. In the present study, we discovered the presence of chitin in the periostracum and identified a novel matrix protein, Pinctada fucata periostracum protein named PPP-10. It was purified from the sodium dodecyl sulfate/dithiothreitol-soluble fraction of the periostracum of the Japanese pearl oyster, P. fucata. The deduced amino acid sequence was determined by a combination of amino acid sequence analysis and cDNA cloning. The open reading frame encoded a precursor protein of 112 amino acid residues including a 21-residue signal peptide. The 91 residues following the signal peptide contained abundant Cys and Tyr residues. PPP-10 was expressed on the outer side of the outer fold in the mantle, indicating that PPP-10 was present in the second or third layer of the periostracum. We also determined that the recombinant PPP-10 had chitin-binding activity and could incorporate chitin into the scaffolds of the periostracum. These results shed light on the early steps in mollusk shell formation

Molecular phylogeny of the rotifers with two Indonesian Brachionus lineages

The rotifer Brachionus plicatilis is an ecologically and commercially important species, and has been studied in various fields such as population dynamics, ecotoxicology and aging. However, recent studies have revealed that the B. plicatilis lineages involve an unknown number of cryptic species, and the group has been regarded as the Brachionus complex. One cause of this complicated taxonomy is the lack of surveys in the tropical zone, which is characterized by enormous species-richness. Accordingly, in this study we collected two Brachionus rotifers from the Sumatra and Sulawesi Islands, Indonesia, and determined their partial nucleotide sequences of mitochondrial DNA cytochrome c oxidase subunit I gene. Subsequently, we constructed molecular phylogenetic trees with fourteen species/lineages from four genera including the two Indonesian rotifers. The two Indonesian Brachionus rotifers were respectively found to be phylogenetically close to B. ibericus and B. rotundiformis. On the other hand, Japanese B. plicatilis was suggested to be phylogenetically closer to B. Manjavacas, which is proposed to be a new species, than to Spanish B. plicatilis. These results imply that the current taxonomy of the Brachionus is problematic, and a major revision is necessary to establish a reliable taxonomy of this group

N-Acetyl-d-Glucosamine-Binding Lectin in Acropora tenuis Attracts Specific Symbiodiniaceae Cell Culture Strains

Many corals establish symbiosis with Symbiodiniaceae cells from surrounding environments, but very few Symbiodiniaceae cells exist in the water column. Given that the N-acetyl-d-glucosamine-binding lectin ActL attracts Symbiodiniaceae cells, we hypothesized that corals must attract Symbiodiniaceae cells using ActL to acquire them. Anti-ActL antibody inhibited acquisition of Symbiodiniaceae cells, and rearing seawater for juvenile Acropora tenuis contained ActL, suggesting that juvenile A. tenuis discharge ActL to attract these cells. Among eight Symbiodiniaceae cultured strains, ActL attracted NBRC102920 (Symbiodinium tridacnidorum) most strongly followed by CS-161 (Symbiodinium tridacnidorum), CCMP2556 (Durusdinium trenchii), and CCMP1633 (Breviolum sp.); however, it did not attract GTP-A6-Sy (Symbiodinium natans), CCMP421 (Effrenium voratum), FKM0207 (Fugacium sp.), and CS-156 (Fugacium sp.). Juvenile polyps of A. tenuis acquired limited Symbiodiniaceae cell strains, and the number of acquired Symbiodiniaceae cells in a polyp also differed from each other. The number of Symbiodiniaceae cells acquired by juvenile polyps of A. tenuis was correlated with the ActL chemotactic activity. Thus, ActL could be used to attract select Symbiodiniaceae cells and help Symbiodiniaceae cell acquisition in juvenile polyps of A. tenuis, facilitating establishment of symbiosis between A. tenuis and Symbiodiniaceae cells

Introduction for Fisheries and Aquatic Biology

Chapter I. Aquatic Environment. Ken FURUYA and Ichiro YASUDA : chapter_1.pdfChapter II. Biology and Ecology of Aqua-Shere. Toyoji KANEKO, Katsumi TSUKAMOTO, Atsushi TSUDA, Yuzuru SUZUKI and Katsufumi SATOH : chapter_2.pdfChapter III. Aquatic Resource and Production. Ichiro AOKI, Kazuo OGAWA, Taku YAMAKAWA and Tomoyoshi YOSHINAGA : chapter_3.pdfChapter IV. Chemistry of Aquatic Organism and Their Utilization. Hiroki ABE, Shugo WATABE, Yoshihiro OCHIAI, Shigeru OKADA, Naoko YOSHIKAWA, Yoshiharu KINOSHITA, Gen KANEKO and Shigeki MATSUNAGA : chapter_4.pdfChapter V. Relation between Aqua-Shere and Human Life. Hisashi KUROKURA, Hirohide MATSUSHIMA, Shingo KUROHAGI, Haruko YAMASHITA, Akinori HINO, Kazumasa IKUTA, Satoquo SEINO, Masahiko ARIJI, Ken FURUYA, Junichiro OKAMOTO and Nobuyuki YAGI : chapter_5.pdfPart of "Introduction for Fisheries and Aquatic Biology