Takeshi Sanekata

Overexpression of monodehydroascorbate reductase in transgenic tobacco confers enhanced tolerance to ozone, salt and polyethylene glycol stresses

Ascorbate (AsA) is a major antioxidant and free-radical scavenger in plants. Monodehydroascorbate reductase (MDAR; EC 1.6.5.4) is crucial for AsA regeneration and essential for maintaining a reduced pool of AsA. To examine whether an overexpressed level of MDAR could minimize the deleterious effects of environmental stresses, we developed transgenic tobacco plants overexpressing Arabidopsis thaliana MDAR gene (AtMDAR1) in the cytosol. Incorporation of the transgene in the genome of tobacco plants was confirmed by PCR and Southern-blot analysis and its expression was confirmed by Northern- and Western-blot analyses. These transgenic plants exhibited up to 2.1-fold higher MDAR activity and 2.2-fold higher level of reduced AsA compared to non-transformed control plants. The transgenic plants showed enhanced stress tolerance in term of significantly higher net photosynthesis rates under ozone, salt and polyethylene glycol (PEG) stresses and greater PSII effective quantum yield under ozone and salt stresses. Furthermore, these transgenic plants exhibited significantly lower hydrogen peroxide level when tested under salt stress. These results demonstrate that an overexpressed level of MDAR properly confers enhanced tolerance against ozone, salt and PEG stress.

Human Group B Rotavirus Infections Cause Severe Diarrhea in Children and Adults in Bangladesh

ABSTRACT Human group B rotavirus was detected in 12 of 220 adult patients and 2 of 67 child patients with severe diarrhea in Bangladesh. Group B rotavirus may be virulent in both adults and children, and the virus may be an especially serious diarrheal agent in Bangladesh.

Porcine Rotavirus Closely Related to Novel Group of Human Rotaviruses

We determined nucleotide sequences and inferred amino acid sequences of viral protein (VP) 4, VP6, VP7, and nonstructural protein 4 genes of a porcine rotavirus strain (SKA-1) from Japan. The strain was closely related to a novel group of human rotavirus strains (B219 and J19).

DRUG RESISTANCE AND CONJUGATIVE R PLASMIDS IN ESCHERICHIA COLI STRAINS ISOLATED FROM MIGRATORY WATERFOWL

We evaluated drug resistance and R plasmids of 554 strains of Escherichia coli isolated from feces of migratory waterfowl, 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.

Necrotic colitis associated with Entamoeba histolytica infection in a cat

A 3-year-old Persian cat developed bloody diarrhoea. On histological examination, a marked necrotic colitis with a large number of invading protozoan parasites was observed. The protozoan was identified as Entamoeba histolytica by light and electron microscopy. This is the first report describing spontaneous amoebiasis in cats.

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.

Detection of porcine rotavirus in stools by a latex agglutination test

Abstract 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 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.

Detection of adenovirus type41 in stool samples by a latex agglutination method

We have developed a simple agglutination (LA) method for the detection of enteric adenovirus (EAd) in stool samples from infants with acute gastroenteritis. Ad type 41 (Ad41) was detected with high sensitivity and specificity by a slide agglutination test using latex particles coated with antiAd41 antibody (LA-antiAd41). The agglutination of LA-antiAd41 with Ad41 on a glass slide was evident macroscopically within 2 min. The sensitivity of the LA method was four times higher than that of the EM method.

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.

Selection of Variants of Avian Infectious Bronchitis Virus Showing Tropism for Different Organs

Avian infectious bronchitis virus strain Kagoshima-34 isolated from the kidneys of a chicken that died of nephrosis/nephritis lost its nephropathogenicity during intratracheal passage in SPF chickens. The resultant virus acquired stronger respirotropism but reduced tropism for kidneys. On the other hand strain Tottori-2 isolated from the trachea of a chicken suffering from severe respiratory disease did not lose its respirotropism after serial intravenous passage in SPF chickens. The serological properties of the passaged virus were investigated by virus neutralisation test. The antibody titres of both strains of virus fluctuated with progressive passage. The serological properties of the virus isolated from respiratory organs were not necessarily the same as those of the isolates made from the kidneys.