Biomedical subjects

K Otsuki

Publications and source records attributed to K Otsuki.

At least 127 records · Page 7Linked to original sources

PubMed1981

Isolation of influenza A viruses from migratory waterfowls in San-in District, Western Japan in 1979-1980.

From December, 1979 to April, 1980, winter migratory waterfowls of some species staying in San-in District, western Japan were surveyed for influenza virus. A total of 27 influenza A viruses, 11 Hav1 Neq1 and 16 Hav6 Nav3, were isolated from 90 fecal specimens of whistling swans. A total of 13 influenza A viruses, 11 Hav1 Neq1 and one Hav6 Nav3, were isolated from 245 fecal samples of black-tailed gulls. Two viruses (Hav1 Neq1) were isolated from 40 tufted ducks. Sampling date, incidence and the antigenic subtype of the isolates were correlated.

Animals↗

PubMed1979

Studies on avian infectious bronchitis virus (IBV). III. Interferon induction by and sensitivity to interferon of IBV.

The induction of interferon by avian infectious bronchitis virus (IBV) and the sensitivity of IBV to interferon were studied. The results of experiments with ten IBV strains are summarized as follows. 1. All the IBV strains tested induced interferon in chick embryo (CE) cells, chicken kidney (CK) cells and embryonated eggs. The Iowa-609 strain induced about 1000 units of interferon in CE cells while the Beaudette-42 strain induced about 200 units of interferon in embryonated eggs; the interferon titers induced by other strains usually ranged from 5 to 60 units. No IBV strain induced interferon in HeLa or BHK-21 cells. 2. IBV particles inactivated by ultraviolet irradiation or by heating lost their ability to induce interferon. 3. The properties of the interferon produced in the present study are similar to those of other interferons produced in chicken cells. 4. HeLa or BHK-21 cells did not acquire resistance to virus infection, after incubation with interferon produced in CE cells. On the other hand, CK cells acquired the same degree of resistance to virus infection as CE cells after incubation with interferon produced in CE cells. 5. All the IBV strains tested were sensitive to interferon in CK cells. The sensitivities of Massachusetts-41 and Holte strains to interferon were similar to that of vesicular stomatitis virus.

Animals↗

PubMed1979

Studies on avian infectious bronchitis virus (IBV). I. Resistance of IBV to chemical and physical treatments.

The resistance of avian infectious bronchitis virus (IBV) to several chemical and physical treatments was studied. Ten strains, including four Japanese strains, were used. 1. All strains were sensitive to heating at 56 degrees C for 15 minutes; although two of them, KH and Massachusetts-41, were resistant to heating at 45 degrees C for 90 minutes. 2. All strains were resistant to pH 3.0 and most of the strains were sensitive to pH 11.0. 3. All strains were completely inactivated by chloroform and sodium deoxycholate and all except Beaudette-42 and Connaught were relatively stable to ether. 4. All strains rapidly lost their infectivities upon ultraviolet irradiation. 5. Trypsin did not affect the infectivity of any strain. 6. From these results, the ten strains were classified into three groups based on their stabilities to exposure to heating at 45 degrees C for 90 minutes and to ether.

Chloroform↗

PubMed1979

Studies on avian infectious bronchitis virus (IBV). II. Propagation of IBV in several cultured cells.

The growth of ten strains of avian infectious bronchitis virus (IBV) in several cultured cells was examined. The cultured cells used were chick kidney (CK), chick embryo (CE), HeLa and BHK-21 cells. The results obtained can be summarized as follows. 1. All the strains showed similar growth curves in CK cells. Progeny viruses appeared in the culture medium 4 to 6 hours after inoculation and peak virus titers of 10(6.5)--10(8.5) TCID50 per 0.1 ml were obtained after 36 hours. A cytopathogenic effect (CPE) was detected within 24 hours. No distinct CPE and low multiplicities were observed on culturing at 30 degrees C. 2. All strains replicated in CE cells, although only small amounts of virus were produced. No CPE was observed. 3. Only Beaudette-42 and Holte strains grew in BHK-21 cells. 4. No IBV strains grew in HeLa cells.

Animals↗

PubMed1979

Isolation of influenza A virus from budgerigars and its serological characterization.

A hemagglutinating agent was isolated from the respiratory organs of budgerigars suffering from diarrhea and malnutrition. This agent, possessing neuraminidase activity, was identified as influenza A virus by the double immunodiffusion test. The results of hemagglutination and neuraminidase-inhibition tests with monospecific antisera to the isolated surface antigens showed that the isolates possessed Hav4 hemagglutinin and Nav1 neuraminidase subunits both of which were closely related to the corresponding antigens of A/duck/Czech/56 (Hav4 Nav1).

Animals↗

PubMed1979

Role of the fly in the transport of Yersinia enterocolitica.

Yersinia enterocolitica were isolated from flies collected from a piggery and a kitchen of farm and from ham hung in a piggery. The cultures were identified as Y. enterocolitica biovar 4 and serovar 3 by biochemical and serological characteristics. From these results it is suggested that flies may play an important role in food contamination by Y. enterocolitica. In this study, the probable donors of Y. enterocolitica to the flies were swine.

Animals↗

PubMed1979

Production of indirect hemolysin by Yersinia enterocolitica and its properties.

Hemolysis was demonstrated on blood agar by adding lecithin from strains of biovar 1 Yersinia enterocolitica. Hemolytic activity was also observed in culture filtrates containing lecithin. No hemolytic activity was detected from any blood agar or culture filtrate without lecithin or after incubation at 37 degrees C. Crude indirect hemolysin was prepared by ammonium sulfate fractionation from culture filtrates, and two enzymes, phospholipase A and lipase, were fractionated by gel filtration. Hemolytic substances were recognized as lysolecithin and fatty acid when lecithin wad decomposed by phospholipase A and lipase, respectively.

Chromatography, Gel↗

PubMed1977