Showing papers by "Hiroshi Yokoyama published in 2014"

First report of Kudoa species in the somatic muscle of the Japanese parrotfish Calotomus japonicus (Scaridae) and a description of Kudoa igami, n. sp. (Myxozoa: Multivalvulida).

Abstract: Three species of the Kudoid parasite (Myxozoa: Multivalvulida) were observed in the somatic muscle of Japanese parrotfish Calotomus japonicus caught off the coast of western Japan. All three species formed pseudocysts in myofibers and caused subclinical infections. The three Kudoa species were distinguished by spore morphology, as well as their 18S and 28S rDNA sequences. We identified a previously undescribed taxa Kudoa igami n. sp. with spores that were stellate with rounded peripheral edges and five to six polar capsules (prevalence 29.3 %). Kudoa igami n. sp. were morphologically most similar to Kudoa neothunni but were distinguishable by a more rounded shape in the apical view. Molecular analyses demonstrated that the K. igami n. sp. is closely related to Kudoa thalassomi; however, the similarity in the 28S rDNA sequence was <96 % and the spore morphology was different. We found Kudoa thalassomi in one sample (prevalence 2.4 %), which is a new host and geographical record for this species. Kudoa lateolabracis, which causes postmortem myoliquefaction in Chinese sea bass Lateolabrax sp. and olive flounder Paralichthys olivaceus was found in Japanese parrotfish (prevalence 41.5 %) for the first time, but did not cause myoliquefaction. We also expanded the host record for the brain-infecting Kudoa yasunagai (prevalence 94.1 %). In addition, an unidentified microsporidia was observed in the somatic muscle (prevalence 23.3 %).

Micropatterned Coumarin Polyester Thin Films Direct Neurite Orientation

Abstract: Guidance and migration of cells in the nervous system is imperative for proper development, maturation, and regeneration. In the peripheral nervous system (PNS), it is challenging for axons to bridge critical-sized injury defects to achieve repair and the central nervous system (CNS) has a very limited ability to regenerate after injury because of its innate injury response. The photoreactivity of the coumarin polyester used in this study enables efficient micropatterning using a custom digital micromirror device (DMD) and has been previously shown to be biodegradable, making these thin films ideal for cell guidance substrates with potential for future in vivo applications. With DMD, we fabricated coumarin polyester thin films into 10 × 20 μm and 15 × 50 μm micropatterns with depths ranging from 15 to 20 nm to enhance nervous system cell alignment. Adult primary neurons, oligodendrocytes, and astrocytes were isolated from rat brain tissue and seeded onto the polymer surfaces. After 24 h, cell type and neu...

Efficacy of High Water Temperature Treatment of Myxosporean Emaciation Disease Caused by Enteromyxum leei (Myxozoa)

Abstract: The efect of elevated water temperature on the myxosporean emaciation disease caused by Enteromyxum leei was tested in experimentaly infected anemonefish Amphiprion ocelaris and naturaly infected Malabar grouper Epinephelus malabaricus. Anemonefish reared at 30°C folowing infection had significantly lower parasite prevalence compared to fish reared at 23°C. After infection in anemonefish held at 23°C for 20 days, elevation of water temperature to 30°C reduced the prevalence. Holding infected Malabar grouper at 30°C resulted in a clearing of E. leei within 6 days. Histopathological observations showed that E. leei was eliminated folowing exfoliation of the intestinal epithelial cels. Although further replication of the study would be required, these results suggested that high water temperature treatment had a preventive and therapeutic efect on myxosporean emaciation

Preparation of Microcapsules Containing Water Droplets Stabilized with Solid Powder and Application to Blowing Agent

Abstract: We have tried to prepare the microcapsules containing water droplets stabilized with solid powder by utilizing the (W/O)/W emulsion The water droplets as core material were stabilized in the monomer droplets with titanium dioxide (TiO2) as a particulate surfactant Before adding the TiO2 powder into the monomer phase, the powder was modified with triethoxyvinylsilane to adjust the degree of hydrophobicity and to promote adhesion on the interface between the inner water phase and the monomer phase in the (W/O) emulsion It was investigated how the degree of hydrophobicity of the TiO2 powder affected the stability of water droplets in the (W/O) emulsion and the (W/O) droplets in the (W/O)/W emulsion Moreover, the microcapsule diameters were measured before and after the expansion operation where the water droplets microencapsulated were applied as a blowing agent The expansion ratio was increased with increase in the stability of the water droplets and the amount of water microencapsulated

Dimensional Analysis and the Time Required to Urinate

Abstract: According to the recently discovered ’Law of Urination’, mammals, ranging in size from mice to elephants, take, on the average, 21s to urinate. We attempt to gain insights into the physical processes responsible for this uniformity using simple dimensional analysis. We assume that the biological apparatus for urination in mammals simply scales with linear size, and consider the scenarios where the driving force is gravity or elasticity, and where the response is dominated by inertia or viscosity. We ask how the time required for urination depends on the length scale, and nd that for the time to be independent of body size, the dominant driving force must be elasticity, and the dominant response viscosity. Our note demonstrates that dimensional analysis can indeed readily give insights into complex physical and biological processes.