Emigration behaviour, moulting and survival during the sea-to-land transition of land hermit crabs Coenobita violascens and Coenobita rugosus under laboratory conditions: Effects of salinity and riverine odours

Coenobita rugosus is distributed along the entire coast, and the distribution of C. violascens is restrictedto the vicinity of rivers, mainly in the mangrove estuaries on southern Japanese islands. To infer theenvironmental cues affecting successful emigration from the sea to land on these species, we examined shellwearing and landing behaviour, moulting and survival for laboratory-raised megalopae and early juveniles under different seawater conditions: 1) high salinity (34 ppt, control), 2) low salinity (24 ppt), and 3) high salinity (34 ppt) with riverine odours (mangrove riverine water). In C. violascens, reduced salinity and riverine odours stimulated shell-wearing activity, and riverine odours enhanced the landing activity. In C. rugosus, reduced salinity and riverine odours stimulated both shell-wearing and landing activities, and the magnitude of the effects was larger in response to reduced salinity than riverine odours. These seawater conditions also tended to enhance the moulting and survival of the animals. Salinity reductions widely occur along the shoreline due to the inflow of groundwater as well as river water. Riverine odours and reduced salinity should be cues for emigration from the sea to land by megalopae of C. violascens and C. rugosus, respectively, thereby characterizing the distributions of these species on the islands

Settlement behaviour of the early megalopae of the land hermit crab Coenobita violascens (Decapoda: Coenobitidae) under laboratory conditions: Effects of inshore odours and salinity

The distribution of the land hermit crab Coenobita violascens is restricted to the vicinity of rivers,particularly mangrove estuaries. To infer the recruitment mechanisms of C. violascens, we examined settlement behaviour, such as swimming, walking, shell-inspection, and shell-wearing activities, in 0-day-old to 6-day-old megalopae under different seawater conditions: 1) offshore salinity (34 ppt, control), 2) offshore salinity (34 ppt) with inshore odours (riverine water), and 3) inshore salinity (24 ppt). Salinity was regulated using artificial sweater salts. Coenobita violascens megalopae exhibited nocturnal swimming activity, whereas other activities significantly increased during the daytime period. Inshore odours did not affect the swimming and walking activities, whereas the inshore salinity conditions decreased the swimming activity and enhanced the walking activity, i.e., stimulated the settlement behaviour of megalopae. Shell-related activities were not influenced by any of the seawater types. Our results suggest that megalopae might migrate to the coast using nocturnal flood-tide transport and settle on or near inshore habitats under the reduced salinity conditions that occur as a result of the inflow of groundwater and river water. Further studies are required to elucidate the role of inshore odours in the recruitment of C. violascens megalopae in mangrove estuaries

Distributions of land hermit crabs (Decapoda: Coenobitidae) on the coast of the tidal lagoon, Nagura Amparu, on Ishigakijima Island, Japan.

　We investigated the distributions of land hermit crabs on the coast of the tidal lagoon, Nagura Amparu, on Ishigakijima Island, Japan, through six surveys conducted during the period from October 2011 to September 2013. Nagura Amparu is a brackish estuary system with a tidal flat and mangrove tree areaseparated from the outer sea bay by a sandbank. Land hermit crabs were captured using bait traps at three sites along the shoreline of the sandbank facing the inner tidal flat and at one site in the coastal forest on the sandbank. Four land hermit crab species, Coenobita brevimanus, C. cavipes, C. rugosus, and C. violascens, were collected. Almost all collected crabs were C. violascens, and a few C. rugosus were collected on the shoreline. On the other hand, C. cavipes was dominant, followed by C. violascens, and a few C. brevimanus were captured in the coastal forest. Coenobita violascens were juveniles and adults, and they widely inhabited the shoreline and coastal forest. All C. cavipes were juveniles, suggesting that this species utilizes the coastal forest as a nursery ground. Our results highlight the importance of the Nagura Amparu as habitat for juveniles and adults of C. violascens and juveniles of C. cavipes

Condensation coefficient of water in a weak condensation state

The condensation coefficient of water at a vapor-liquid interface is determined by combining shock tube experiments and numerical simulations of the Gaussian-BGK Boltzmann equation. The time evolution in thickness of a liquid film, which is formed on the shock tube endwall behind the shock wave reflected at the endwall, is measured with an optical interferometer consisting of the physical beam and the reference one. The reference beam is utilized to eliminate systematic noises from the physical beam. The growth rate of the film is evaluated from the measured time evolution and it is incorporated into the kinetic boundary condition for the Boltzmann equation. From a numerical simulation using the boundary condition, the condensation coefficient of water is uniquely deduced. The results show that, in a condition of weak condensation near a vapor-liquid equilibrium state, the condensation coefficient of water is almost equal to the evaporation coefficient estimated by molecular dynamics simulations near a vapor-liquid equilibrium state and it decreases as the system becomes a nonequilibrium state. The condensation coefficient of water is nearly identical with that of methanol (Mikami et al., 2006)

Ontogenetic change of body color patterns in laboratory-raised juveniles of six terrestrial hermit crab species

Hamasaki, Katsuyuki, Tsuru, Takuma, Sanda, Tetsuya, Fujikawa, Shunsuke, Dan, Shigeki, Kitada, Shuichi (2017): Ontogenetic change of body color patterns in laboratory-raised juveniles of six terrestrial hermit crab species. Zootaxa 4226 (4): 521-545, DOI: https://doi.org/10.11646/zootaxa.4226.4.

Investigation of the anti-tumor mechanism of tirabrutinib, a highly selective Bruton's tyrosine kinase inhibitor, by phosphoproteomics and transcriptomics.

Tirabrutinib is a highly selective Bruton's tyrosine kinase (BTK) inhibitor used to treat hematological malignancies. We analyzed the anti-tumor mechanism of tirabrutinib using phosphoproteomic and transcriptomic methods. It is important to check the drug's selectivity against off-target proteins to understand the anti-tumor mechanism based on the on-target drug effect. Tirabrutinib's selectivity was evaluated by biochemical kinase profiling assays, peripheral blood mononuclear cell stimulation assays, and the BioMAP system. Next, in vitro and in vivo analyses of the anti-tumor mechanisms were conducted in activated B-cell-like diffuse large B-cell lymphoma (ABC-DLBCL) cells followed by phosphoproteomic and transcriptomic analyses. In vitro kinase assays showed that, compared with ibrutinib, tirabrutinib and other second-generation BTK inhibitors demonstrated a highly selective kinase profile. Data from in vitro cellular systems showed that tirabrutinib selectively affected B-cells. Tirabrutinib inhibited the cell growth of both TMD8 and U-2932 cells in correlation with the inhibition of BTK autophosphorylation. Phosphoproteomic analysis revealed the downregulation of ERK and AKT pathways in TMD8. In the TMD8 subcutaneous xenograft model, tirabrutinib showed a dose-dependent anti-tumor effect. Transcriptomic analysis indicated that IRF4 gene expression signatures had decreased in the tirabrutinib groups. In conclusion, tirabrutinib exerted an anti-tumor effect by regulating multiple BTK downstream signaling proteins, such as NF-κB, AKT, and ERK, in ABC-DLBCL