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M Tsubokura

Publications and source records attributed to M Tsubokura.

At least 19 recordsLinked to original sources
PubMed2001

Geographical heterogeneity between Far Eastern and Western countries in prevalence of the virulence plasmid, the superantigen Yersinia pseudotuberculosis-derived mitogen, and the high-pathogenicity island among Yersinia pseudotuberculosis strains.

Yersinia pseudotuberculosis produces novel superantigenic toxins designated YPMa (Y. pseudotuberculosis-derived mitogen), YPMb, and YPMc and has a pathogenicity island termed HPI (high-pathogenicity island) and R-HPI (the right-hand part of the HPI with truncation in its left-hand part) on the chromosome. Analysis of the distribution of these virulence factors allowed for differentiation of species Y. pseudotuberculosis into six subgroups, thus reflecting the geographical spread of two main clones: the YPMa(+) HPI(-) Far Eastern systemic pathogenic type belonging to serotypes O1b, -2a, -2b, -2c, -3, -4a, -4b, -5a, -5b, -6, -10, and UT (untypeable) and the YPMs(-) HPI(+) European gastroenteric pathogenic type belonging to serotypes O1a and -1b. The YPMa(+) HPI(+) pathogenic type belonging to serotypes O1b, -3, -5a, -5b, and UT and the YPMb(+) HPI(-) nonpathogenic type belonging to non-melibiose-fermenting serotypes O1b, -5a, -5b, -6, -7, -9, -10, -11, and -12 were prevalent in the Far East. The YPMc(+) R-HPI(+) European low-pathogenicity type belonging to non-melibiose-fermenting serotype O3 and the YPMs(-) HPI(-) pathogenic type belonging to 15 serotypes were found to be prevalent all over the world. This new information is useful for a better understanding of the evolution and spread of Y. pseudotuberculosis.

Americas↗
PubMed1998

Analysis of the superantigen-producing ability of Yersinia pseudotuberculosis strains of various serotypes isolated from patients with systemic or gastroenteric infections, wildlife animals and natural environments.

Yersinia pseudotuberculosis is a pathogen causing gastroenteritis as well as acute and systemic infections. This organism produces a superantigenic exotoxin, designated Y. pseudotuberculosis-derived mitogen (YPM). We consider this exotoxin to be the primary pathogen of the systemic type infection. In this study, we examined 101 Y. pseudotuberculosis strains isolated from various sources, patients with the systemic or the gastroenteric type of infections, wildlife animals and natural environments for the presence of the YPM gene and the production of YPM or other related superantigens. We found that all of the strains isolated from patients with systemic type infection carried the YPM gene and produced YPM. A certain proportion of the organisms isolated from patients with the gastroenteric type infection, wildlife animals or natural environments did not carry the YPM gene nor produced superantigens. These results suggest that YPM is involved in the pathogenesis of the systemic type of Y. pseudotuberculosis infection.

Animals↗
PubMed1998

[Standardization of hemopoietic colony assay reagents].

Several Japanese Red Cross blood centers have begun cooperating with hospitals in peripheral blood stem cell transplantation research. However, most have not yet standardized their techniques or reagents for that purpose yet. Consequently, wide variations are often observed in data from different blood centers, especially for hemopoietic colony assays. We compared our colony assay reagent set with those in three commercial colony assay kits. The best results were obtained with the kit from a manufacturer referred to here as company A. Although our reagent set obtained lower colony values, the CFU-GM, BFU-E, and total colony values correlated well with those obtained using company A's kit (r = 0.74, 0.80, and 0.97, respectively). Company A's kit gave reproducible results even with the use of different lots, and includes reagents that can be stored for up to two years at -20 degrees C. These features highlighted its advantages as a standard reagent set.

Colony-Forming Units Assay↗
PubMed1997

Characteristics and pathogenicity of non-melibiose-fermenting strains of Yersinia pseudotuberculosis O3.

The biological properties of non-melibiose-fermenting (NMF) strains of Yersinia pseudotuberculosis O3 were investigated. These strains were clearly distinguished from representative melibiose-fermenting (MF) strains of Y. pseudotuberculosis O3 by their pathogenicity in mice, sensitivity to some phages, production of catalase, restriction endonuclease analysis of virulence plasmid DNA with BamHI, detection of specific yersinia outer-membrane proteins with SDS-PAGE, antigenicity of the outer-membrane proteins and neutrophil resistance to phagocytosis. The pathogenicity of NMF strains was clearly less than that of MF strains. In addition, the resistance of NMF strains to phagocytosis and catalase activity was evidently weaker than that of MF strains. These results suggested that the difference of pathogenicity was due to the ability of catalase production. Although the relationship between the above characteristics and melibiose-fermentation was not analysed, the pathogenicity of Y. pseudotuberculosis O3 strains can probably be predicted by testing melibiose-fermentation and catalase production.

Animals↗
PubMed1997

Identification of pathogenic strains within serogroups of Yersinia pseudotuberculosis and the presence of non-pathogenic strains isolated from animals and the environment.

The existence of apathogenic strains of Yersinia pseudotuberculosis (Yp) has not so far been reported. Recently, the authors characterized new serogroups and a new subgroup in Yp, that is, O9, O10, O12, O13 and O14 and O1c, and the pathogenicity of these new strains was of interest. A total of 137 strains of serogroups O1c, O6, O7, O9, O10, O11, O12, O13 and O14 of Yp were investigated for their pathogenicity in vivo and in vitro. Although catalase activity and the inv gene were detected in all strains except those of groups O13 and O14, only a few strains, from serogroups O6 and O10 caused severe infection in mice. The remaining strains caused no mortality or severe infection even when they grew in limited tissues of infected mice. All the strains of Yp not possessing the virulence plasmid p YV caused no severe infection in mice. It is evident that less pathogenic Yp exists and that not only pathogenic but also less pathogenic Yp organisms exist in the same serogroup.

Animals↗
PubMed1996

Latex agglutination test for canine parvovirus.

Canine parvovirus (CPV) was detected in faeces from dogs with diarrhoea by a specific slide agglutination test using latex particles coated with anti-CPV monoclonal antibody (LA-anti-CPV). The agglutination of LA-anti-CPV with CPV on a glass slide was evident macroscopically within 2 min. The sensitivity of the latex agglutination (LA) test was similar to that of the hemagglutination test. The LA test is available for the rapid diagnosis of CPV infection at an animal hospital.

Animals↗
PubMed1995

Isolation of Yersinia pseudotuberculosis from river waters in Japan and Germany using direct KOH and HeLa cell treatments.

Yersinia pseudotuberculosis was recovered from precipitates directly treated with KOH and/or HeLa cell in 25.7% of 680 river water samples collected in Japan. Recovery was nil in similar samples from Germany. Treatment of precipitates by KOH and infection of HeLa cells, respectively, is an expedient and selective means for isolation of Y. pseudotuberculosis from such samples.

Animals↗
PubMed1995

Yersinia pseudotuberculosis in China.

Thirty strains of Yersinia pseudotuberculosis were isolated from rabbits (17 strains), wild rats (9 strains) and house rats (4 strains) in China between 1990 and 1993. The biochemical properties of these isolates were identical with those of Y. pseudotuberculosis and no special characteristics were found in these strains. Serologically, serogroups 4b and 5b were identical to isolates found in Japan, and a new serogroup 1c and unclassified strains have also been detected. The existence of virulence-associated properties were different among strains. The pYV plasmid was detected from 6 strains of 30 isolates. This report documents the presence of Y. pseudotuberculosis in China, providing important epidemiological information.

Animals↗
PubMed1995

Drug resistance and conjugative R plasmids in Escherichia coli strains isolated from migratory waterfowl.

We evaluated drug resistance and R plasmids of 554 stains of Escherichia coli isolated from feces of migratory watefowl, including whistling swans (Cygnus columbianus), pintails (Anas acuta) and black-tailed gulls (Larus crassirostris) collected from the San-in District, Japan, between each November and March, 1983 to 1984, 1984 to 1985, and 1985 to 1986. Seven antimicrobial agents were tested: dihydrostreptomycin (DSM), kanamycin, spectinomycin, ampicillin (ABPC), oxytetracycline (OTC), chloramphenicol, and sulfadimethoxine (SDMX). Many strains were resistant to several drugs; in particular, all strains were resistant to SDMX. Both multiple drug resistant strains and drug resistance patterns occurred most frequently in strains isolated from whistling swans, followed by black-tailed gulls, and pintails, respectively. Of 233 strains, 128 (55%) carried transmissible R plasmids. The drugs with the largest number of resistance patterns observed were, in descending order, OTC, DSM, ABPC, and SDXM.

Animals↗
PubMed1994

Experimental infection with avian infectious bronchitis virus (Kagoshima-34 strain) in chicks at different ages.

Chicks at 2, 4 or 6 weeks of age were experimentally infected individually with a nephrosis/nephritis-causing avian infectious bronchitis virus (IBV) strain Kagoshima-34. The susceptibility of chicks in each group to the infection was compared, based on the clinical signs, excretion of virus in the faeces and antibody titres in the serum. The results showed that although all chicks appeared to be susceptible to IBV infection, the most severe clinical response was observed following infection at 2-week-old. Likewise, whilst the virus was also recovered from the faeces of all the chicks infected, the duration of viral excretion was longest in the 2-week-old chicks. A high antibody titre was detected at 4 weeks post infection (PI) and was maintained for at least another 16 weeks in the 4- and 6-week-old chicks. In contrast, a low antibody titre was detected only between 8 to 12 weeks PI in the 2-week-old chicks. Thereafter, no antibody was detected despite the presence of clinical signs.

Aging↗
PubMed1994

Comparison of the susceptibility of chicks of different ages to infection with nephrosis/nephritis-causing strain of infectious bronchitis virus.

Two- and 6-week-old chicks were inoculated with the Kagoshima-34 strain of avian infectious bronchitis virus. Serum, bile, Harderian gland, lachrymal fluid, saliva and tracheal washings were collected and their antibody content determined using neutralisation tests. The neutralising antibody (NA) in the serum and bile was detected earlier and in slightly higher concentration in the 6-week-old chicks. Although there was no marked difference in the levels of NA in other body fluids, it was detected earlier in the 6-week-old chicks. In both experiments, the clinical signs were more severe in the 2-week-old chicks. Recovery of virus from the trachea of both ages was not different but virus was recovered for longer in the lungs, kidneys and colon of the 2-week-old chicks. This is the first report wherein IBV-neutralising antibody in the bile is described.

Aging↗
PubMed1993

Characterization of Yersinia pseudotuberculosis serogroups O9, O10 and O11; subdivision of O1 serogroup into O1a, O1b, and O1c subgroups.

In this study, three new antigens (O9, O10 and O11) of Yersinia pseudotuberculosis are described. The O1 antigen is further subdivided into O1a, O1b and O1c. The methods used to prepare specific antisera for O-antigen identification are also described. Furthermore, the H antigens of these new serogroups are determined and their biochemical characteristics analysed. The antigenic formulae of the known serogroups within the basic antigenic scheme introduced by the authors' laboratories are presented.

Antigenic Variation↗
PubMed1993

Differentiation of Yersinia enterocolitica serotype O:5,27 strains by phenotypic and molecular techniques.

Restriction endonuclease analyses of virulence plasmid DNA (REAP) and chromosomal DNA and other phenotypic characteristics were used to study the differentiation of Yersinia enterocolitica serotype O:5,27 strains. There was a close correlation between REAP patterns and the geographical distribution of serotype O:5,27. Human isolates produced only one REAP pattern, which was also found with isolates from pigs and dogs.

Animals↗
PubMed1992

Characterization of an amorphous and soluble hemagglutinin from Yersinia pseudotuberculosis.

Yersinia pseudotuberculosis which were screened out depending on auto-agglutination and Ca2+ dependency, were examined for their production of hemagglutinin (HA), and its purification and characterization were performed. The HA with a broad reactivity with various mammalian erythrocytes was recovered from the culture supernatant of these strains grown at 37 C but not 25 C. HAs from two strains, R148R and T1040, were purified by salt precipitation, gel filtration and anion-exchange chromatography by HPLC. Both purified HAs were cysteine-deficient acidic protein with an apparent molecular weight in the range of 15,000 to 16,000. N-terminal amino acid sequences of the first 25 residues were found to share 12% identity with that of afimbrial adhesin from enterotoxigenic Escherichia coli 2230. Immunoelectron microscopy and immunodiffusion test with polyclonal antiserum raised against the purified R148RHA demonstrated that the HA was associated with the amorphous aggregates which were detached from bacteria. These results suggest that the HA of Y. pseudotuberculosis belongs to a third type of HA produced by the yersinial species.

Amino Acid Sequence↗
PubMed1991

Detection of porcine rotavirus in stools by a latex agglutination test.

We developed a simple agglutination test for the detection of porcine rotavirus in stools from pigs with diarrhea. The virus was detected with high sensitivity and specificity by a slide agglutination test using latex particles coated with antibody against the porcine rotavirus strain OSU (LA-antiOSU). The agglutination of LA-antiOSU with OSU on a glass slide was evident macroscopically within 2 min. The sensitivity of this latex agglutination (LA) test was four times higher than that of the electron microscope method. The LA test is available for the rapid diagnosis of porcine rotavirus infections.

Animals↗