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Biomedical subjects

M Yoshimizu

Publications and source records attributed to M Yoshimizu.

14 recordsLinked to original sources
PubMed2002

Oligonucleotide probe for detecting Enterobacteriaceae by in situ hybridization.

AIMS: To develop oligonucleotide probes for visualizing bacteria belonging to Enterobacteriaceae. METHODS AND RESULTS: 24-mer oligonucleotide probe (probe D) was designed by comparison of 16S rDNA sequences of 35 species of Enterobacteriaceae, eight species of Vibrionaceae and six species of Pasteurellaceae. The sequence of the probe corresponding to the complementary sequence of a position 1251-1274 of Escherichia coli 16S rRNA was found to be a highly conserved region of 16S rDNA sequence in Enterobacteriaceae different from that of Vibrionaceae and Pasteurellaceae. The fluorescent dye-labelled probe was tested for the specificity by in situ hybridization and epifluorescence microscopy. Seventy-six out of 78 strains belonging to Enterobacteriaceae were visualized in an optimal hybridization condition. No bacterial strains belonging to Vibrionaceae (31 strains) and Gram-positive bacteria (three strains) were visualized. CONCLUSIONS: In situ hybridization using probe D allows the detection of bacterial cells belonging to Enterobacteriaceae without false positive reaction. SIGNIFICANCE AND IMPACT OF THE STUDY: In situ hybridization techniques using the probe D are potential tools for detecting Enterobacteriaceae in food and water samples.

DNA, Bacterial↗
PubMed2000

Selection of brood stock candidates of barfin flounder using an ELISA system with recombinant protein of barfin flounder nervous necrosis virus.

Barfin flounder nervous necrosis virus (BFNNV), the causative agent of viral nervous necrosis (VNN) of barfin flounder, is vertically transmitted from spawners to larvae. In the present study, an ELISA with a recombinant protein of BFNNV was performed for the detection of antibodies against BFNNV and applied for the selection of brood fish in order to prevent viral vertical transmissions. Brood stocks were divided into 4 groups based on ELISA antibody titers (< or = 10, 20, 40 and >40), and the BFNNV status of the brood stocks was determined by PCR. BFNNV was detected from the brood fish in the group with an antibody titer of >40 but not from those with titers < or = 10, 20 and 40. The offspring obtained from PCR-negative brood fish pairs in each group of ELISA antibody titers were subsequently reared for observation of VNN occurrence. VNN occurred in juveniles from 2 of 9 pairs of spawners with an antibody titer > or = 40, but did not occur in spawners with an antibody titer of < or = 10. Therefore, it was concluded that selection of brood fish using both the PCR test and ELISA antibody titers could help prevent vertical transmission of BFNNV in larval production of barfin flounder.

Animals↗
PubMed1998

Vibrio spp., the dominant flora in shrimp hatchery against some fish pathogenic viruses.

Two strains of Vibrio spp., NICA 1030 and NICA 1031, which are the dominant flora in shrimp hatcheries, were studied for antiviral activity by exposing them to the infectious hematopoietic necrosis virus (IHNV) and Oncorhynchus masou virus (OMV) before being inoculated to the CHSE-214 cells. Antiviral activities were exhibited as plaque reduction percentages of 98 and 92% for the NICA 1030 and of 99 and 62% for the NICA 1031, respectively.

Journal Article↗
PubMed1996

Disease problems of salmonid fish in Japan caused by international trade.

The author details the connection between disease outbreaks in salmonid fish and imports of salmonid eggs into Japan since the 1950s. The following diseases and species are involved: -infectious pancreatic necrosis in rainbow trout (Oncorhynchus mykiss) -infectious haematopoietic necrosis in sockeye ( of 'kokanee') salmon (O. nerka) and masu salmon (O. masu) -cold water disease, erythrocyte inclusion body syndrome, and bacterial kidney disease (caused by Renibacterium salmoninarum) in coho salmon (O. kisutch), ayu (Plecoglossus altivelis), rainbow trout and masu salmon. The author also discusses the strategies aimed at controlling the risk of disease spread through international trade in salmonid fish and fish products in Japan. Essential in these strategies are the following actions: -exchange of information on controlling disease problems -studies to establish standard methods to identify or detect fish pathogens -fish health certification.

Animals↗
PubMed1996

[Fish viruses].

Explore the source record for details and available documents.

Animals↗
PubMed1995

Salmonid herpesvirus 2. Epizootiology and serological relationship.

Herpesvirus infections of kokanee salmon, masu salmon, coho salmon, and rainbow trout have been reported in Japan. The 11 herpesvirus strains isolated from kokanee salmon (NeVTA), masu salmon (YTV and 3 strains of OMV), coho salmon (CSTV, COTV and 2 strains of OKV), rainbow trout (RKV and RHV), and Herpesvirus salmonis were compared for their serological relatedness by serum cross-neutralization tests with polyclonal rabbit antiserum. The herpesvirus strains isolated in Japan were neutralized by antisera against these viruses and were found to be closely related to salmonid herpesvirus 2 (OMV strain 00-7812). These strains were, however, clearly distinguished from salmonid herpesvirus 1 (H salmonis).

Animals↗
PubMed1992

Detection of viral DNA polymerase activity in salmon tumour tissue induced by herpes virus, Oncorhynchus masou virus.

DNA polymerase activities were surveyed in tumour tissue and normal tissue of cherry salmon (Oncorhynchus masou). High activity of DNA polymerase alpha was detected in the tumour tissue but not in the normal tissue. This indicates that the tumour cells replicate prosperously. Viral DNA polymerase activity was detected only in the tumour tissue, indicating that Oncorhynchus masou virus (OMV) DNA should replicate there. DNA polymerase beta activity was of same level in both tissues. This is the first evidence that herpesvirus DNA polymerase was detected in tumour tissue in association with herpesvirus.

Animals↗
PubMed1991

Comparison of different Oncorhynchus masou virus (OMV) strains by DNA restriction endonuclease cleavage analysis.

Seven strains of Oncorhynchus masou virus (OMV) genomes were analyzed with the restriction endonucleases BamHI, EcoRI, HindIII and SmaI. The restriction patterns of OMV strain DNAs were divided into four groups. Restriction profiles of high passage strains (00-7812, 65th passage, and H-83, 60th passage) were different from those of low passage strains (00-7812, 8th passage, and H-83, 6th passage) when digested with BamHI, HindIII and SmaI. However, no difference was observed between the restriction patterns of high and low passage viral DNA with EcoRI. There was no distinct difference observed between the restriction patterns of tumor tissue-derived and coelomic fluid-derived strains. By using 32P-labelled DNA of standard OMV (strain 00-7812) as a probe, most of the fragments of other OMV strain DNAs were hybridized.

Animals↗
PubMed1990

Inhibitory effect of halocyamine, an antimicrobial substance from ascidian hemocytes, on the growth of fish viruses and marine bacteria.

Halocyamine A, an antimicrobial substance isolated from hemocytes of the solitary ascidian Halocynthia roretzi, inhibited in vitro the growth of fish RNA viruses (infectious hematopoietic necrosis virus and infectious pancreatic necrosis virus). Pretreatment of RNA virus with halocyamine A reduced the infectivity of the virus toward host cells. The growth of marine bacteria, Achromobacter aquamarinus and Pseudomonas perfectomarinus, was also inhibited by halocyamine A but that of Alteromonas putrefaciens and Vibrio anguillarum was not. These results suggest that halocyamine may have a role in the defense mechanisms of H. roretzi against marine viruses and bacteria.

Animals↗
PubMed1988

Inhibitory activity of (E)-5-(2-bromovinyl)-2'-deoxyuridine on the salmonid herpesviruses, Oncorhynchus masou virus (OMV) and Herpesvirus salmonis.

The highly potent and selective anti-herpesvirus agent, (E)-5-(2-bromovinyl)-2'deoxyuridine (BVdU), was examined for its inhibitory effect on the salmonid herpesviruses Oncorhynchus masou virus (OMV) and Herpesvirus salmonis (H. salmonis). Minimum inhibitory concentrations (MIC) of BVdU for OMV and H. salmonis were 1.25 and 3.0 micrograms/ml, respectively; these values were equal to or higher than those obtained for acyclovir or cytarabine. OMV DNA polymerase activity was reduced in a dose-dependent fashion by BVdU 5'-triphosphate (BVdUTP) within the concentration range of 3 to 30 microM. However, BVdUTP could also be substituted for the natural substrate, TTP, in the OMV DNA polymerase assay. It is postulated that the inhibitory action of BVdU on the salmonid herpesviruses is more or less similar to that on other herpesviruses and resides with respect to the inhibition of the virus DNA polymerase activity as well as incorporation of BVdU into the viral DNA.

Acyclovir↗
PubMed1988

Screening of bacteria with antiviral activity from fresh water salmonid hatcheries.

Bacteria isolated from two salmonid hatcheries were screened for antiviral activity against infectious hematopoietic necrosis virus (IHNV) to ascertain the presence of bacteria with anti-IHNV activity in the aquatic environment. Out of 710 bacterial isolates from the water and sediment samples, 190 strains showed anti-IHNV activities of more than 50% plaque reduction. These antiviral activities were detected predominantly in Pseudomonas, Aeromonas/Vibrio, and coryneforms. In one hatchery, the bacteria with antiviral activities were more prevalent in sediment samples than in water samples. Seventy-seven percent of the isolates with higher antiviral activities (greater than 90% plaque reduction) belonged to Pseudomonas.

Animals↗
PubMed1983

In vitro antiviral effect of 9-(2-hydroxyethoxymethyl) guanine on the fish herpesvirus, Oncorhynchus masou virus (OMV).

The antiviral activity of 9-(2-hydroxyethoxymethyl) guanine (Acyclovir, ACV) on the salmon herpesvirus, Oncorhynchus masou virus (OMV), was studied in vitro. ACV showed high efficacy against the fish herpesvirus OMV, Herpesvirus salmonis and channel catfish virus (CCV). Cytopathic effect (CPE) induced by 100 TCID50/ml of OMV in rainbow trout gonad (RTG-2) cells was inhibited by 2.5 micrograms/ml of ACV. ACV was more effective than other compounds such as 9-beta-D-arabinofuranosyladenine (Ara-A), 5-iodo-2'-deoxyuridine (IUdR) and phosphonoacetate (PA). Growth of RTG-2 cells was considerably inhibited by ACV at 25 microgram/ml, but no morphological changes were observed in the cells. Replication of OMV in RTG-2 cells inoculated with 100 TCID50/ml was completely suppressed by 2.5 microgram/ml of ACV. Addition of ACV within 4 days post infection was effective in reducing OMV replication. In order to be effective, ACV had to be present continuously.

Acyclovir↗
PubMed1983

In vivo antiviral effect of 9-(2-hydroxyethoxymethyl) guanine on experimental infection of chum salmon (Oncorhynchus keta) fry with Oncorhynchus masou virus (OMV).

The therapeutic efficacy of 9-(2-hydroxyethoxymethyl) guanine (Acyclovir, ACV) was evaluated using Oncorhynchus masou virus (OMV) and chum salmon fry. The fish, which were experimentally infected with OMV, were treated with ACV either orally or by the immersion method. Daily immersion of fish into ACV solution (25 microgram/ml, 30 min/day, 15 times) reduced mortality of the infected fish. Oral administration of the drug (25 microgram/fish per day, 60 times) did not affect survival of the chum salmon. On the contrary, the group administered 5-iodo-2'-deoxyuridine (IUdR) by the oral route showed a higher survival than the ACV-administered group. This suggested that an effective level of ACV was not maintained in fish given the drug by the oral route. Daily immersion of infected fish into ACV solution (25 microgram/ml, 30 min/day, 60 times) considerably suppressed the development of tumors induced by OMV.

Acyclovir↗