Diagnostic and preventive practices for iridovirus in marine fish

The first outbreak of red sea bream iridoviral disease (RSIVD) caused by red sea bream iridovirus (RSIV) was recorded among cultured red sea bream (Pagrus major) in 1990 in Ehime, Shikoku, Japan. Since then, the disease has caused mass mortalities of many cultured marine fishes. From 1990-2000, RSIVD was detected in 31 cultured marine fish species, including 28 Perciformes, 2 Pleuronectiformes and 1 Teteraodontiformes, in 18 prefectures in the southwestern part of Japan. The infected fish are lethargic and show severe anemia, petechiae of the gills, and enlargement of the spleen. Histopathologically, the disease is characterized by the presence of enlarged cells in the spleen, heart, kidney, liver and gills that are deeply stained with Giemsa solution. Diagnostic methods for RSIV, such as the observation of stained imprints or tissue sections, an immunofluorescent (IF) test with a monoclonal antibody (MAb) and a polymerase chain reaction (PCR) technique have been developed. The IF test with MAb is commonly used in the rapid diagnosis of RSIV-infected fish. For an effective control measure against RSIVD, a formalin-killed vaccine has been developed and this showed a significant effect in red sea bream under both experimental and field conditions

Adsorption of Bovine Serum Albumin and γ-Globulin on Chitosan Membrane

Adsorption of proteins on chitosan, which has positively charged proups, was investigated. The amount of adsorption depended on pH values and showed the maximum at the isoelectric point of BSA (pH 4.5-5.0) as was recognized in non-charged polymer membl-anes. Also it depended on an ionic strength, which affected the maximum point as well as the amount itself. It was considered that the positive charge of chitosan may affect the isoelectric point of BSA at which the smallest lateral interaction appeared to make the compactest form of BSA molecule. Whereas, contrary to the general tendency observed at much lower concentration of BSA, the amount of maximum adsorption decreased as the ionic st.rength decreased. This suggests that at relatively high concentration, the reduction of shielding effect of ions may give the increase of repulsion between BSA molecules rather than that of interaction between BSA and chitosan molecules. The adsorption of γ-globulin was studied, too. Futhermore, the adsorption of chitosan onto a silk fiber as substitute for human hair was studied to result in the usefulness as the rinsing agent

Spectral Evolution of the Unusual Slow Nova V5558 Sgr

We report on the spectral evolution of the enigmatic, very slow nova V5558 Sgr, based on the low-resolution spectra obtained at the Fujii-Bisei Observatory and the Bisei Astronomical Observatory, Japan during a period of 2007 April 6 to 2008 May 3. V5558 Sgr shows a pre-maximum halt and then several flare-like rebrightenings, which is similar to another very slow nova V723 Cas. In our observations, the spectral type of V5558 Sgr evolved from the He/N type toward the Fe II type during the pre-maximum halt, and then toward the He/N type again. This course of spectral transition was observed for the first time in the long history of the nova research. In the rebrightening stage after the initial brightness maximum, we could identify many emission lines accompanied by a stronger absorption component of the P-Cygni profile at the brightness maxima. We found that the velocity of the P-Cygni absorption component measured from the emission peak decreased at the brightness maxima. Furthermore, we compared the spectra of V5558 Sgr with V723 Cas, and other novae which exhibited several rebrightenings during the early phase.Comment: 8 pages, 7figures, accepted for publication in PAS