Assessment of coastal anthropo-ecological system dynamics in response to a tsunami catastrophe of an unprecedented magnitude encountered in Japan.

On 11 March 2011, a catastrophic earthquake and subsequent tsunami hit the Pacific coast of northern Japan, devastating many of the towns, villages and coastal ecosystems located along the shoreline. To assess the impacts of the disaster, we investigated temporal dynamics of fish and epibenthic megafaunal community structure in relation to changes in a range of physical, biological and anthropogenic variables between 2007 and 2018 in Onagawa Bay. Commercially important fish such as greenlings, Japanese anchovy, flatfishes, rockfishes were consistently abundant in both larval and adult fish assemblages. While abundance, species richness, and Shannon index H' for adult fish and epibenthic megafaunal assemblages increased significantly soon after the disaster to peak values towards the end of the study period, the same metrics did not change accordingly for larval fish assemblages. Temporal dynamics of larval fish community clearly demonstrated significant seasonal variation along with changes in large-scale environmental conditions such as temperature and nutrients. However, anthropogenic components such as decline in human population, reduction in fishing pressure and the recovery of aquaculture operations significantly explained the observed post-disaster change in adult fish and epibenthic megafaunal communities. The pelagic and benthic components of Onagawa Bay appeared to have responded to the 2011 disaster very differently, and this study suggests the post-disaster recovery and dynamics of the coastal ecosystems may be regulated by how human societies respond to the impacts of a tsunami catastrophe through their influences on benthic habitat of ecosystems.

Novel microsatellite marker development from the unassembled genome sequence data of the marbled flounder Pseudopleuronectes yokohamae.

Various genome-scale data have been increasingly published in diverged species, but they can be reused for other purposes by re-analyzing in other ways. As a case study to utilize the published genome data, we developed microsatellite markers from the genome sequence data (assembled contigs and unassembled reads) of the marbled flounder Pseudopleuronectes yokohamae. No microsatellites were identified in the contig sequences, whereas the computer software found 781,773 sequences containing microsatellites with di- to hexa-nucleotide motif in the unassembled reads. For 86,732 unique sequences among them, a total of 331,368 primer pairs were designed. Screening based on PCR amplification, polymorphisms and accurate genotyping resulted in sixteen primer sets, which were later characterized using 45 samples collected in Onagawa Bay, Miyagi, Japan. The presence of null alleles was suggested at four loci in the studied population but no evidence of allelic dropout was found. The observed number of alleles and heterozygosity was 2-20 and 0-0.88889, respectively, indicating polymorphisms and usefulness for population genetic analyses of this species. In addition, a large number of the microsatellite primers developed in this study are potentially applicable also for kinship estimation, individual fingerprint and linkage map construction.

Complete mitochondrial DNA sequence and phylogenetic analysis of Zhikong scallop Chlamys farreri (Bivalvia: Pectinidae).

The complete mitochondrial genome of Zhikong scallop Chlamys farreri is 21,695 bp in length and contains 12 protein-coding genes (the atp8 gene is absent, as in most bivalves), 2 ribosomal RNA genes, and 22 transfer RNA genes. The heavy strand has an overall A+T content of 58.7%. GC and AT skews for the mt genome of C. farreri are 0.337 and -0.184, respectively, indicating the nucleotide bias against C and A. The mitochondrial gene order of C. farreri differs drastically from the scallops Argopecten irradians, Mimachlamys nobilis and Placopecten magellanicus, which belong to the same family Pectinidae. 6623 bp non-coding nucleotides exist intergenically in the mitogenome of C. farreri, with a large continuous sequence (4763 bp) between tRNA ( Val ) and tRNA ( Asn ). Two repeat families are found in the large continuous sequence, which seems to be a common feature of scallops. Phylogenetic analysis based on 12 concatenated amino acid sequences of protein-coding genes supports the monophyly of Pectinidae and paraphyletic Pteriomorphia with respect to Heteroconchia.

Removal characteristics of wipe devices under various conditions.

Understanding the removal factor for specific conditions is essential to estimate removable surface contamination levels by wiping. The removal characteristics of dry foamed polystyrene pads and filter paper applied to polyvinyl chloride flooring are investigated using C-thymidine under various conditions (i.e., weight of contaminants, wax coating, temperature and humidity). Eight wipes were performed per flooring piece with a uniformly deposited contaminant to estimate the total removable surface contamination. The wipe devices were pressed against the surface by 2 kg-force with fingertips. The first wipe ratio (the ratio of the activity removed by the first wipe to the activity removed by eight wipes) from flooring on which was deposited 500 microg mL of C-thymidine solution varies between 24% and 71% for polystyrene pads and between 33% and 83% for filter papers, depending on the atmospheric humidity and temperature. For deposition concentrations of 1 microg mL, the mean first wipe ratio using polystyrene pads, which are almost constant vs. humidity and temperature, are 68% and 24% for waxed and unwaxed surfaces, respectively. Under the same conditions, the mean first wipe ratio for filter paper varied with both the surface and the environmental conditions. The total recovery (the ratio of the total activity removed by eight wipes to the total deposited activity) for deposition concentrations of 500 microg mL tended to increase with humidity for both wiping devices. The total recovery for deposition concentrations of 1 microg mL is generally low. The first wipe ratio in the lowest case with foamed polystyrene pads in this study was 19%. In that case, the total removable activity is speculated to increase from the sum of eight wipes, if additional wipes are performed. Therefore, the theoretical value of 0.1 recommended by ISO for the removal factor is appropriate when wiping polyvinyl chloride flooring using foamed polystyrene pads.

Permanent Genetic Resources added to Molecular Ecology Resources Database 1 June 2010 - 31 July 2010.

This article documents the addition of 205 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Bagassa guianensis, Bulweria bulwerii, Camelus bactrianus, Chaenogobius annularis, Creontiades dilutus, Diachasmimorpha tryoni, Dioscorea alata, Euhrychiopsis lecontei, Gmelina arborea, Haliotis discus hannai, Hirtella physophora, Melanaphis sacchari, Munida isos, Thaumastocoris peregrinus and Tuberolachnus salignus. These loci were cross-tested on the following species: Halobaena caerulea, Procellaria aequinoctialis, Oceanodroma monteiroi, Camelus ferus, Creontiades pacificus, Dioscorea rotundata, Dioscorea praehensilis, Dioscorea abyssinica, Dioscorea nummularia, Dioscorea transversa, Dioscorea esculenta, Dioscorea pentaphylla, Dioscorea trifida, Hirtella bicornis, Hirtella glandulosa, Licania alba, Licania canescens, Licania membranaceae, Couepia guianensis and 7 undescribed Thaumastocoris species.

Involvement of GnRH neuron in the spermatogonial proliferation of the scallop, Patinopecten yessoensiss.

The aim of this study was to quantitatively analyze a pattern of proliferation of gonial cells and to demonstrate neural involvement in spermatogonial proliferation of the scallop by the in vitro experiment. Immunocytochemistry for incorporated BrdU was used to identify mitotically active gonial cells. The pattern of proliferation of gonial cells was divided into two phases: phase I; oogonia and spermatogonia slowly proliferate through the growing stage: phase II; oogonia develop into oocytes and spermatogonia start to proliferate rapidly from the mature stage through the spawning stage. The neurons detected with anti-mammalian (m)GnRH antibody were distributed sparsely in the pedal ganglion and predominantly in the cerebral ganglion of both sexes at the growing stage. The extracts from the cerebral and pedal ganglion (CPG) of both sexes collected at the growing stage promoted proliferation of spermatogonia in the in vitro culture of the testicular tissue as well as mGnRH. However, CPG extract had no effect on oogonial proliferation. The increased mitotic activity induced by CPG and mGnRH was abolished by the addition of mGnRH antagonists and anti-mGnRH antibody, suggesting that the spermatogonial proliferation is regulated by GnRH-like peptide in CPG of the scallop. The same mitotic activity as CPG extract and mGnRH was observed in the hemocyte lysate, but not in the serum. These findings suggest that the spermatogonial proliferation at phase II in the scallop may be under the neuroendocrine control by GnRH neuron in CPG.

Microsatellite analysis of Japanese sea cucumber, Stichopus (Apostichopus) japonicus, supports reproductive isolation in color variants.

The genetic relationship among the three color variants (Red, Green, and Black) of the Japanese sea cucumber, S. japonicus, was investigated using 11 microsatellite markers. Genetic differentiation testing among the three sympatric color types showed the strong heterogeneity of Red (p<0.001), while no significant difference was observed between Green and Black (p=0.301 to 0.961). UPGMA trees constructed from 10 sample lots from 5 localities showed two distinct clusters, one from the Red types and the other from the Green and Black types. In addition, the sympatric Green and Black formed one subcluster with strong bootstrap support at each locality. These results indicate the separate species status of Red and the other color types, and also support the population identity of sympatric Green and Black.

A novel oocyte maturation arresting factor in the central nervous system of scallops inhibits serotonin-induced oocyte maturation and spawning of bivalve mollusks.

Serotonin (5-hydroxytriptamine; 5-HT) is a major neurotransmitter that triggers oocyte maturation and sequential spawning in bivalve mollusks. A proteinous and heat-labile substance that proved to be a novel inhibitor of 5-HT-induced egg release from ovarian tissue was found in the cerebral and pedal ganglia (CPG) of the scallop Patinopecten yessoensis. The same inhibitory activity was also observed in the proteinous fraction from the supernatant of hemolymph. Histological observation demonstrated that the novel inhibitor prevented 5-HT from inducing oocyte maturation in the scallop ovary and that no prostaglandin F2alpha (PGF2alpha) inhibited 5-HT-induced oocyte maturation, although PGF2alpha strongly prohibited 5-HT-induced egg release through the gonoduct from ovarian tissue. The novel inhibitor from the scallop CPG also prohibited 5-HT-induced oocyte maturation of other bivalve species as well as scallops. The novel inhibitor, mediated through a receptor mechanism on oocyte membranes, blocked extracellular Ca2+ uptake into oocytes, which was observed in 5-HT-induced oocyte maturation. It is suggested that the novel inhibitor with a molecular mass of 60 kDa, named oocyte maturation arresting factor, which appears to be a universal substance for bivalve species, may be transported from the CPG to the ovary via hemolymph and may prohibit 5-HT-induced oocyte maturation due to the interference of extracellular Ca2+ influx into oocytes, eventually resulting in the inhibition of spawning. On the other hand, it seems that PGF2alpha inhibits 5-HT-induced transport of mature eggs through the gonoduct.

Segregation of microsatellite alleles in gynogenetic diploid Pacific abalone (Haliotis discus hannai).

Inheritance of 9 microsatellite loci was examined in 3 families of gynogenetic Pacific abalone Haliotis discus hannai produced by fertilizing eggs with UV-irradiated sperm followed by inhibition of the second meiotic division. The proportion of heterozygous progeny was used to estimate marker-centromere (M-C) distances. All loci conformed to Mendelian segregation in the control crosses when null alleles were accounted for. The absence of paternal alleles confirmed the gynogenetic origin of the offspring and indicated 100% success for 3 families. Estimated recombinant frequencies ranged from 0.10 to 0.60, which is lower than those observed in other gynogenetic diploid animals. The mean recombination frequency was 0.22, corresponding to a fixation index of 0.78 in one generation. This is 3.12 times the increase in homozygosity expected after one generation of sib mating (0.25), suggesting meiotic gynogenesis may be an effective means of rapid inbreeding in the abalone. M-C map distances for the 9 loci varied between 5 and 30 cM under the assumption of complete interference. The information about M-C distances will be useful for future gene mapping in H. discus hannai.

Isolation and characterization of twenty microsatellite loci in Japanese sea cucumber (Stichopus japonicus).

Twenty microsatellite markers were first developed from the Japanese sea cucumber Stichopus japonicus using an enrichment protocol. Of the 20 microsatellite loci, 19 loci were polymorphic in the population examined. At these polymorphic loci, the number of alleles per locus varied from 2 to 15, and the observed heterozygosities ranged from 0.03 to 0.97, which is considerably higher than those previously found for allozymes. The high variability of the microsatellite markers identified in this study will make them excellent tools for genetic analyses of S. japonicus.

Induction of haploid androgenesis in Pacific oyster by UV irradiation.

Androgenesis, development from paternal but not maternal chromosomes, can be induced in some organisms including fish, but has not been induced previously in mollusk. In this study we investigated the induction of haploid androgenesis in the Pacific oyster by ultraviolet irradiation and observed nuclear behavior in the androgenetic eggs. Irradiation for 90 seconds at a UV intensity of 72 erg/mm2 per second (6480 erg/mm2) was the optimal dose to achieve haploid androgenesis. The fertilization and development rates of D-shaped larvae decreased with increasing exposure time, and the development of the genetically inactivated eggs terminated before reaching the D-shaped stage. Cytologic observations showed that UV irradiation did not affect germinal vesicle breakdown or chromosomal condensation but caused various nuclear behavioral patterns during meiosis and first mitosis: 21.7% of eggs extruded all maternal chromosomes as 2 or 3 polar bodies, and 59.1% of eggs formed one female pronucleus. The maternally derived nucleus did not participate, or partially participated, in the first karyokinesis. The cytologic evidence demonstrates that the male genome is directing development in haploids produced by UV irradiation.

Molecular cloning and expression analysis of vitellogenin in scallop, Patinopecten yessoensis (Bivalvia, Mollusca).

The present study was undertaken to determine scallop vitellogenin (Vtg) cDNA sequence, to identify Vtg synthesizing cell, and to analyze the regulation of Vtg mRNA expression. Clones containing partial cDNA sequence of Vtg were isolated from cDNA library of the scallop ovary by immunoscreening with the anti-scallop vitellin (Vn) serum. The deduced amino acid sequence of the clone containing the longest cDNA insert (1,689 bp) was identified as a member of the lipid transport protein family and exhibited about 20-35% identity with Vtgs of other oviparous animals. Northern blot analysis identified a single transcript longer than 10 kb in the ovary. Dot blot analysis of the ovary showed a high amount of Vtg mRNA during the growing stage and the level was retained until spawning stage. In situ hybridization demonstrated the expression of Vtg mRNA in the auxiliary cells closely associated with growing oocytes, suggesting that the synthesis of a major yolk protein in the scallop occurs through hetero-synthetic pathway without mediation through the blood flow but occurs de novo in the ovary. The content of Vtg mRNA in the ovarian tissue cultured in vitro with vitellogenesis promoting factor (VPF), which strongly promotes Vtg protein synthesis, from the cerebral plus pedal ganglion (CPG) showed no change. The transcription of Vtg mRNA appeared to be promoted by estradiol-17beta (E2) not by VPF although VPF may enhance the translation of Vtg mRNA.

Inheritance of microsatellite DNA markers in the Pacific abalone Haliotis discus hannai.

Microsatellite markers have been developed for a variety of abalones, and locus-specific homozygote excesses at population level have been recorded for microsatellite loci. To ascertain whether null alleles exist at microsatellite loci in the Pacific abalone, we studied the mode of inheritance of 7 microsatellite loci in 4 families with a reciprocal cross of 2 females x 2 males. All loci segregated codominantly, but only 3 loci ( Hdh1321, Hdh78, and Hdd108C) conformed to Mendelian segregation and can be used for parental analysis and population genetic studies. When null alleles were considered, 2 loci (Hdh1761 and Hdh1457) confirmed Mendelian expectations in all families, while the remaining 2 loci (Hdd114B and Hdd229) showed deviation from Mendelian segregation in at least one family even though null alleles were considered. These results indicated the need to test the inheritance pattern for microsatellite markers in abalones before using them for population genetic of parentage analysis.