Explore the vast range of titles available.

A new species of Leptostraca, Sarsinebalia agoensis sp. nov. , from Ago Bay, Japan is described from specimens found at a depth of 120 m. The new species differs from other known Sarsinebalia species as follows: the compound eye has three distal lobes; the anterior margin of the first antennal segment has one distal process covered with setae; and the lateral margin of pleopod 1 exopod bears 5–6 simple, robust spines. A taxonomic key to all species of Sarsinebalia is also provided.

The stochastic and elite models have been proposed for the mechanism of induced pluripotent stem (iPS) cell generation. In this study we report a system that supports the elite model. We previously identified multilineage-differentiating stress-enduring (Muse) cells in human dermal fibroblasts that are characterized by stress tolerance, expression of pluripotency markers, self-renewal, and the ability to differentiate into endodermal-, mesodermal-, and ectodermal-lineage cells from a single cell. They can be isolated as stage-specific embryonic antigen-3/CD105 double-positive cells. When human fibroblasts were separated into Muse and non-Muse cells and transduced with Oct3/4, Sox2, Klf4, and c-Myc, iPS cells were generated exclusively from Muse cells but not from non-Muse cells. Although some colonies were formed from non-Muse cells, they were unlike iPS cells. Furthermore, epigenetic alterations were not seen, and some of the major pluripotency markers were not expressed for the entire period during iPS cell generation. These findings were confirmed further using cells transduced with a single polycistronic virus vector encoding all four factors. The results demonstrate that in adult human fibroblasts a subset of preexisting adult stem cells whose properties are similar in some respects to those of iPS cells selectively become iPS cells, but the remaining cells make no contribution to the generation of iPS cells. Therefore this system seems to fit the elite model rather than the stochastic model.

A new species of Leptostraca, Nebalia tagiri sp. nov. is described and illustrated. This species was sampled from 200 m depth at a hydrothermal field in Wakamiko Caldera of Kagoshima Bay, Japan. Nebalia tagiri sp. nov. is different from known Nebalia species as follows: rostral length 2.4 times as long as width; article 4 of antennule with 3–5 robust distal spines; antennular scale approximately twice as long as wide; article 3 of antenna with eight spines and nine spine-like setae along proximal half, two thin setae and six spine-like setae on external lateral face, six spines and four simple setae on distal margin; article 1 of second maxilla longer than article 2; article 2 of mandibular palp with two thin setae; exopod of pleopod 1 with 21 spines along lateral margin; furcal rami longer than combined length of pleonite 7 and telson; rounded denticles of pleonite 6 and 7; anal-plates ‘shoulder’ not distinct. Furthermore, this specimen is the first genus Nebalia found in the hydrothermal vent. The distribution and ecology of this new species is also discussed and a key to all species of Nebalia is provided.

The nitrogen (δ¹⁵N) and carbon stable isotope (δ¹³C) values of six species of euphausiids predominant in the northwestern (NW) Pacific Ocean were investigated to elucidate speciesspecific feeding habits and seasonal and regional differences. The order of annual mean δ¹⁵N values was: Tessarabrachion oculatum Hansen, 1911 (11.2 ± 0.8‰) > Thysanoessa longipes Brandt, 1851 (10.4 ± 0.4‰) > Thysanoessa inspinata Nemoto, 1963 (9.3 ± 0.8‰) > Nematoscelis difficilis Hansen, 1911 (8.2 ± 1.4‰) > Euphausia pacifica Hansen, 1911 (7.7 ± 0.5‰) > Euphausia gibboides Ortmann, 1893 (6.9 ± 0.9‰). The trophic levels of four species based on δ¹⁵N values were estimated as 3.6, 3.2, 2.9, and 2.5 for T. oculatum, T. longipes, T. inspinata, and E. pacifica, respectively, in the Oyashio region in June 2011. The seasonal differences in δ¹⁵N values of these species were relatively small, which suggests euphausiids play the same role in the food web throughout the year. Carapace lengths were negatively correlated with δ¹⁵N values of five species except T. longipes. Regional differences in stable isotope ratios that might reflect regional differences in the primary producer signature were observed: higher δ¹³C values and lower δ¹⁵N values in the Oyashio–Kuroshio mixed water region compared to those in the Oyashio region. The biplot of δ¹³C and δ¹⁵N annual mean values with zooplankton in the NW Pacific shows that euphausiids have a wide range of δ¹⁵N values, suggesting they play diverse roles in the pelagic food web in the region.

Species composition, diversity and biomass of jellyfish (Cnidaria and Ctenophora), with their spatio-temporal distributions, were analyzed in the upper 1500 m of the Oyashio front, the Transition zone and the Kuroshio extension, off Tohoku, northeastern Japan, between May 2005 and March 2006. Species composition and abundance differed remarkably between the shallower layer and the deeper layer at the boundary of 300-500 m depth, where water density was within the range of the North Pacific Intermediate Water. In the deeper layer, diversity reached its peak with the appearance of 27 taxa common in all the regions throughout the year, though abundance was low. Pantachogon haeckeli and Crossota rufobrunnea were dominant in the deeper layer. The possibility of diel vertical migration was suggested in two midwater species: Euphysa japonica and Atolla vanhoeffeni. In the Oyashio waters, jellyfish abundance was much higher than in the Transition waters and Kuroshio-derived waters, but with low diversity, dominated by large numbers of Aglantha digitale and Dimophyes arctica. High values of diversity were found in the Kuroshio-derived waters with various tropical and warm-water species, especially calycophoran siphonophores being present. In the Transition waters, diversity was relatively high, with co-occurrence of warm-water species and cold-water species. Jellyfish biomass tended to be high in the midwater zone due to the occurrence of large species, particularly Scyphozoa. Carbon-based jellyfish biomass calibrated with other studies exceeded that of other organism groups.

 A new species of Leptostraca, Sarsinebalia agoensis sp. nov. , from Ago Bay, Japan is described from specimens found at a depth of 120 m. The new species differs from other known Sarsinebalia species as follows: the compound eye has three distal lobes; the anterior margin of the first antennal segment has one distal process covered with setae; and the lateral margin of pleopod 1 exopod bears 5-6 simple, robust spines. A taxonomic key to all species of Sarsinebalia is also provided. Keywords: Ago Bay, biodiversity, Malacostraca , taxonomic key

We surveyed the distribution of colonies of polyps of Aurelia aurita sensu lato (s.l.) in Mikawa Bay, Japan. First, we surveyed the distribution of ephyrae of A. aurita s.l. at 75 stations encompassing the whole of Mikawa Bay in early 2008. A total of 37 ephyrae were sampled mostly from fishing ports. Ephyrae were most abundant around the islands located near the mouth of the bay, and decreased from the western part to the eastern part of Mikawa Bay. Next, we selected five fishing ports in Mikawa Bay where ephyrae occurred and surveyed the underside of floating piers and underwater overhangs of wharfs. We found dense colonies of polyps of A. aurita s.l. under nearly all of the floating piers at the two islands located near the mouth of the bay. Fitting a logistic regression model to the dataset showed that the percentage coverage of Aurelia polyps was significantly greater at the two islands compared with the other locations. In addition, the coverage of Aurelia polyps was greater when the coverage of other fouling organisms was in the range of 65-90%, and the coverage of Aurelia polyps was lower on floating piers with a vinyl surface and on concrete wharfs. The combined distribution of polyp colonies of A. aurita s.l. in Ise Bay and Mikawa Bay suggested that A. aurita s.l. in the two bays probably forms a single population and shoals of medusae mainly originate from protected harbors along the mouth-part of the bays.[PUBLICATION ABSTRACT]

The diversity of protistan microplankton in Sagami Bay was revealed by 18S rRNA gene clone analysis using newly designed PCR primers. PCR amplification consisted of a first reaction targeting the V3–V5 region of the 18S rRNA gene, followed by a nested reaction targeting the V3–V4 region. In total, 629 clones consisting of 108 phylotypes were affiliated with a variety of protistan groups including dinoflagellates, diatoms, prymnesiomonada, chlorophyta, ciliophora, cercozoa, and heterokonta. The dinoflagellate group was detected most frequently and shared approximately 74 % of the total clones. Within this group, approximately half of the clones belonged to the parasitic dinoflagellate Syndiniales group I, which was first reported from Sagami Bay. The genera Woloszynskia , Gonyaulax , Neoceratium , and Karlodinium have not been reported from this bay until now. The second most frequent group was diatoms, which shared approximately 22 % of the total clones. Within this group, highly diverse Thalassiosira phylotypes were detected, and they shared approximately 70 % of the diatom clones. Therefore, highly diverse protists including some candidate groups were successfully detected, indicating that the designed primers and PCR protocol will be useful for molecular diversity analyses of protistan microplankton communities in aquatic environments.

The relationship between euphausiid community structure and water region was studied during a 2-year seasonal survey in the northwestern (NW) Pacific Ocean. The euphausiid community structure and its associated species were analyzed from 38 micronekton samples collected during eight cruises. The euphausiid community structure and its distribution patterns clearly corresponded to physical oceanographic features in the Oyashio region, Oyashio–Kuroshio Mixed Water Region (OKMWR), and Kuroshio region. In contrast, community structure was unrelated to seasonality. The 19 species out of 40 identified in this area were grouped and named after their habitats. The six cold-water species were grouped into three regional types: two coastal Oyashio species, three Oyashio–OKMWR species, and one Oyashio–Kuroshio species. The four species dominating in the OKMWR were categorized into each specific types: Nematoscelis difficilis as OKMWR–Oyashio species, Euphausia gibboides as OKMWR species, Euphausia similis as OKMWR–Oyashio & OKMWR–Kuroshio species, and Euphausia recurva as OKMWR–Kuroshio species. The seven warm-water species were categorized as Kuroshio–OKMWR species or Kuroshio species. The other two species were categorized as cosmopolitan species. In particular, regarding the result in the OKMWR, our study suggest that (1) the OKMWR has high species diversity, and (2) the dominant species, such as Euphausia pacifica , N. difficilis , E. similis , and E. gibboides , are considered to be key species in the food webs in this region.

Seasonal changes in diversity and community structure of planktonic copepods at a shelf site in Sagami Bay, Japan was studied in relation to cross-shelf interaction of species components. Seasonal mesozooplankton samples were collected from the shelf station (St. M) of the north-west part of Sagami Bay from 1995 to 1997. Vertical multi-layered samples were collected near the center of Sagami Bay (St. P) in June 1996. A total 185 copepod species were identified from the two stations. We observed a clear seasonal succession in calanoid diversity and community structure at St. M from a simple shelf water community (>11 species) during spring blooming periods to highly diverse and mixed communities (ca 20-30 species) of shelf water species coupled with various Kuroshio Current species during late summer to autumn. Cluster and non-metric multidimensional scaling ordination analyses showed two distinct calanoid community groups. One group, which included samples of St. M and the surface layer of St. P, consisted of shelf water species, such as Calanus sinicus, Ctenocalanus vanus, Paracalanus spp., and Kuroshio species, such as, Canthocalanus pauper, Scolecithrix danae, etc. The other cluster was restricted to the samples collected from mid and deep layers at St. P, which consisted of meso- and bathypelagic species and Oyashio species (cold-current species, such as Neocalanus cristatus, Pseudocalanus spp., Eucalanus bungii and Metridia pacifica). In the mid and deep layers at St. P, the population of dormant copepodid stage V (CV) of Eucalanus californicus and C. sinicus were dominant. The deep CV population of C. sinicus might be ecologically discriminated from the surface and shelf water population due to their larger body length and dormant life cycle. E. californicus was also collected at the shelf site during each spring bloom period, whereas the population might descend into the mid- and deep-layers of the central bay before summer. Our results suggest that the seasonal fluctuation of community structure in the shelf water was controlled by both physical (Kuroshio Current) and biological factors, i.e., spring bloom and ontogenetic vertical migration of E. californicus. In particular, transport and diffusion processes of Kuroshio Current in Sagami Bay played a key role in controlling the shelf water calanoid community.[PUBLICATION ABSTRACT]