The modulatory effects of oxytetracycline treatments at high concentrations on the infection potential of scuticociliates in cultured juvenile olive flounder (Paralichthys olivaceus) and density of the ciliates in culturing water were investigated. The groups bathed with 400 and 500 ppm of oxytetracycline showed significantly lower intensities of scuticociliates on the fish and considerably lower number of the ciliates in culturing water when compared with the control group. However, the intensity of scuticociliates on the fish in the group bathed with 300 ppm of oxytetracycline was not significantly different with that of the control group in spite of considerably lower number of scuticociliates in culturing water than in that of the control group. Although the intensities of scuticociliates on the fish intubated orally with 400 and 500 mg/kg of oxytetracycline were lower than that of the control group, there were no statistical significances. In contrast, the fish fed 300 mg/kg of oxytetracycline showed significantly lower intensity of scuticociliates when compared with other groups. The results of this study suggest that oxytetracycline treatments can modulate occurrence of scuticociliatosis in fish farms probably through change of bacterial density, damaging to scuticociliatosis and immuno-suppression of fish.

To investigate the effect of mechanical parameters on the circulation and its fluctuation in Sagami Bay, baroclinic model experiments were carried out by use of a two-layer source-sink flow in a rotating tank. In the experiment, a simple coastal topography with flat bottom was reproduced. The results show that the path of the Through Flow, which corresponds to the branch current of the Kuroshio, depends on external Rossby number (Ro) and internal Rossby number $(Ro^*)$, and divided into two regimes. For $Ro^*\leq1.0$ in which Rossby internal radius of deformation of the Through Flow is smaller than the width of the approaching channel, the current flows along the Oshima Island as a coastal boundary density current separated from the western boundary of the channel. For $Ro^*>1.0$ it changes to a jet flow along the western boundary of the channel, separated from the coast of Oshima Island. The current is independent on both Ro and Ro* in the regime of $Ro^*>1.0,\;Ro\geq0.06$ and $Ro^*\leq1.0,\;Ro\geq0.06$. The pattern of the cyclonic circulation in the inner part of the bay is also determined by Ro and Ro*. In case of $Ro^*\leq1.0$, frontal eddies are formed in the northern boundary of the Through Flow. These frontal eddies intrude into the inner part along the eastern boundary of the bay providing vorticity to form and maintain the inner cyclonic circulation. For $Ro^*>1.0$, the wakes from the Izu peninsula are superposed intensifying the cyclonic circulation. The pattern of the cyclonic circulation is divided into three types; 1) weak cyclonic circulation and the inner anticyclonic circulation $(Ro<0.12)$. 2) cyclonic circulation in the bay $(0.12\leq Ro<0.25)$. 3) cyclonic circulation with strong boundary current $(RO\geq0.25)$.

Angiotensin I converting enzyme inhibitory activities of shelled krill (Euphausia superba) hydrolysates by autolysis and by hydrolysis with commercial proteases were analyzed. Among the proteases, Alcalase was the most effective protease for the hydrolysis of krill considering the degree of hydrolysis $(87.5\%)$ and the ACE inhibitory activity $(60\%)$. Four hour hydrolysis suggested as the most suitable and economic. In order to establish the optimum hydrolysis condition of krill, degree of hydrolysis and ACE inhibitory activity as affected by Alcalase concentration and water amount added were statistically analyzed by response surface methodology (RSM). The optimum hydrolysis condition was $2.0\%$ Alcalase hydrolysis in 2 volumes (v/w) of water at $55\% for 4 hr. The hydrolysate prepared from the optimum hydrolysis condition was fractionated by molecular weight. The lower molecular weight fraction showed the higher ACE inhibitory activity. $IC_{50}$ of the fraction under 500 Da was 0.57mg protein/mL.

Effects of cimetidine, a cytochrome P450 inhibitor, on the benzo[a]pyrene (BaP)-mediated cytochrome P450 induction and lipid peroxidation of liver in olive flounder, Paralichthys olivaceus, were investigated. Fish were fed either a cimetidine-supplemented diet or a cimetidine-free control diet once daily to satiation for 3 days. After 6 hrs of last feeding, the fish received intraperitoneal (i.p.) injection of BaP (20 mg/kg of body weight) dissolved in sterile corn oil $(100 \mu L)$ or received only a corn oil i.p. injection. At 1, 2, 3, and 7 days after the injection, hepatic cytochrome P450 and thiobarbituric acid reactive substances (TBARS), an indicator of lipid peroxidation, were analyzed. BaP injection resulted in an increase of hepatic cytochrome P450, and the fish fed the cimetidine-supplemented diet before injection of BaP showed delayed increase of hepatic cytochrome P450 compared to the fish fed a cimetidine-free diet and BaP injected. Injection of BaP clearly induced hepatic lipid peroxidation, and consistently higher TBAR values were shown in the fish fed a cimetidine­supplemented diet before injection of BaP than the fish injected with BaP alone.

In this study, we investigated the mechanism of cell death in rhabdovirus-infected cells, chinook salmon embryonic cell line (CHSE-2l4) infected with hirame rhabdovirus (HIRRV). Studies using light microscopy, fluorescence microscopy, TUNEL method, electron microscopy, and agarose gel electrophoresis revealed changes in the cell morphology and DNA fragmentation indicative of apoptosis in early infection. It was observed that HIRRV induced apoptosis as well as necrosis in infected cells.

Microarrayer is used to make DNA chip and microarray that contain hundreds to thousands of immobilized DNA probes on surface of a microscope slide. This paper shows the develop-ment results for a printing type of microarrayer. It realizes a typical, low-cost and efficient microarrayer for generating low density micro array. The microarrayer is developed by using a prependicular type robot with three axes. It is composed of a computer-controlled three-axes robot and a pen tip assembly. The key component of the arrayer is the print-head containing the tips to immobilize cDNA, genomic DNA or similar biological material on glass surface. The robot is designed to automatically collect probes from two 96-well plates with up to 12 pens at the same time. To prove the performance of the developed microarrayer, we use the general water types of inks such as black, blue and red. The inks are distributed at proper positions of 96 well plates and the three color inks are immobilized on the slide glass under the operation procedure. As the result of the test, we can see that it has sufficient performance for the production of low integrated DNA chip consisted of 96 spots within $1cm^2$ area.

Jeotgal, salt- fermented sea food, is a kind of Korean traditional foods. We carried out hazard analysis on Changran (stomach and intestine of Alaska pollack) Jeotgal and squid Jeotgal through the whole processing procedures at H Co. located at Guryongpo from April 2000 to September 2001. During this studying period, we educated employee regularly and analyzed hazards on the whole process and then could conclude that pathogenic bacteria and metal particles were most important hazards in Jeotgal. Metal particles in end-product will be eliminated by laser detector before packaging. But bacteria must thoroughly manage through the whole process. Bacteriological qualities of the end products were much improved after education for the employees and by effort for HACCP (Hazard Analysis and Critical Control Point) program introduction. Pathogenic bacteria such as pathogenic Escherichia coli, Salmonella spp., coagulase positive Staphylococcus aureus and Vibrio parahaemolyticus were not detected from not only raw materials but also end products. The falling bacteria in the places such as thawing area, packaging area, seasoning area, fermenting room, subsidiary materials room and storage room were less than 30 CFU per plate for 30 minutes during working time. But those were increased more than 10 times during the resting time. It means that special measures are needed during the break time such as lunch time or exchanging working teams.

The HACCP (hazard analysis critical control point) concept becomes an important aspect of Good Manufacturing Practices (GMP) in safe food production. The HACCP plan was developed with food safety objective. The authors already carried out hazards analysis on Changran Jeotgal manufacturing process in a previous report. In this study we developed a HACCP plan on the manufacturing process of Changran Jeotgal. We could decide two CCPs those were salt concentration and eliminations of foreign materials before packaging. Foreign materials should be certainly checked out with laser detector just before packaging. Salt should be maintained more than $8\%$ to inhibit pathogenic bacteria in end product. On the Jeotgal process free water is removed after salting and Jeotgal is seasoned with several subsidiary materials such as com syrup. In result end products have $8\%$ salt with water activity 0.82. Most bacteria are inhibited but some can live in this condition. Materials on the working may be contaminate by pathogens, chemicals or physical hazards. It will be decreased by SSOP (standard sanitary operating program). The SSOP needed in Jeotgal plants is nearly same as other general food manufacturing plants but essential to fulfill HACCP program.

The polymerase chain reaction (PCR) amplification technique was used for comparison of Listeria monocytogenes serotypes. PCR primers for the fragment of invasion-associated protein (iap) gene were highly specific for all the serotypes of L. monocytogenes. Other Listeria spp., such as Listeria ivanovii and Listeria innocua were not produced the PCR fragments by above primer set. The nucleotide sequences of PCR products showed high homologies in comparison of all the isolated serotypes except unknown type II-2. The deduced amino acid sequences of the PCR products also showed similar to one another. The various region of the PCR products, called a Thr-Asn repeat region was presented. All of isolated L. monocytogenes serotypes possessed 16 to 20 Thr-Asn repeats.

Swim up fry of the Nile tilapia, Oreochromis niloticus, were fed 0 or 60 mg l7-methyltestos­terone (MT) per kg feed for 30 days. Fish that had been fed 0 or 60 ppm MT for the first 30 days were subsequently fed a commercial diet for 56 weeks to evaluate growth, survival, sex ratio, body composition, gonadosomatic index and the total edible portion. Mean body weight of MT treated group and untreated group were 1.7 g and 1.1 g, respectively at the end of the treatment for 30 days $(P<0.05)$. The experiment was terminated after a total of 60 weeks, the mean body weight of the MT treated population was 1,016 g and that of the untreated population was 762g $(P<0.05)$. However, the final mean body weight of untreated males (l, 086g) was not significantly different from treated males (l,016 g), but the mean body weight of the female group was 512 g. Therefore, the reason for the lower mean body weight of the untreated group was entirely due to stunted females. The percentage fillet yield of MT treated fish$(34.6\%)$ was not significantly different from that of the untreated males $(34.4\%)$, but the untreated females were lower than those of both treated and untreated male groups $(32.4\%)$ (P<0.05). There were no significant differences in the percentage of the all edible portion (AP) between MT treated and untreated males, but females were lower than males. Females are smaller fish in size and the gonads are larger in proportion which were discarded along with the intestine this explains the observed difference. Total biomass of the two groups were 134.8kg and 104.5kg per $m^3$, respectively. The proportion of fish reaching a marketable size of over 800 g in body weight within 14 months were $78\%$ in the MT treated group and $41\%$ in the untreated group.

The proper conditions for cold storage of milt in four species of flatfish were investigated. Various diluents were tested for the preservation of marbled sole, brown sole, starry flounder and olive flounder milt at $1\pm0.5^{\circ}C$ for 7 days. The most effective diluent was $1\%$ NaCl for marbled sole and Stein's extender for brown sole, starry flounder and olive flounder. After 7 days of storage in different dilution ratios (milt: diluent), marbled sole milt diluted with 1:3-10 and brown sole, starry flounder and olive flounder milt diluted 1:1-10 maintained good sperm activity index (SAI). SAI was affected by storage volume and presence of antibiotic. SAI was lower after 7 days storage in the volume of 1.5 mL than in 0.5 or 1.0 mL. SAI after 29 days storage was markedly enhanced by addition of antibiotic in marbled sole (400 ppm gentamicin, 400 ppm neomycin, 200-400 ppm streptomycin), brown sole (600 ppm gentamicin), starry flounder (1,000 ppm gentamicin) and olive flounder (200-1,000 ppm gentamicin, 200-400 ppm neomycin, 200-1,000 ppm streptomycin).

The effects of Coehlodinium polykrikoides on the gill of red sea bream, Pagrus major, were examined to clarify the ichthyotoxic mechanisms of this plankton species. The gill of fish exposed to dense blooms over 3,000 cells/mL for 24 h showed severe epithelial separation: a severe edema was found in the secondary lamellar epithelium and interlamellar regions of primary filament. In addition, lipid peroxidation of gill tissue in Coehlodinium-exposed fish was about 2.5 times higher than that of control. The composition of glycoproteins in the gill mucus of Coehlodinium-exposed fish was also changed. These results suggest that the loss of structural integrity of cell membranes in fish gill may be deeply involved in fish death by C. polykrikoides.