No abstract

Herpes simplex virus type 1 (HSV-1) is a ubiquitous human pathogen. The a sequence of HSV-1 is the cis-acting site required for the cleavage and encapsidation of unit-length HSV-1 DNA from concatemeric forms. The consensus a sequence consists of (i) DR1 (direct repeat 1), (ii) Ub, (iii) a DR2 array [a repeat of various copy numbers of DR2 elements (11 or 12 bp)], (iv) a DR4 stretch and (v) Uc. In the present study, the nucleotide sequences of the a sequences of 26 HSV-1 isolates were determined and the DR4 stretches were classified into three groups. The state of a set of 20 DNA polymorphisms in the genomes of these HSV-1 isolates was determined previously. A correct classification rate of 100 % was achieved when discriminant analysis was performed between the DR4 stretch (criterion variable) and the set of 20 DNA polymorphisms (predictor variables), suggesting a close association of the DR4 stretch with HSV-1 diversification. DR2 elements of 9, 13 and 14 bp were detected in addition to those of 11 and 12 bp, and a correct classification rate of 93 % was achieved when discriminant analysis was performed between the DR2 array and the set of 20 DNA polymorphisms. Some DR2 elements of one HSV-1 isolate had the same nucleotide sequences as part of the adjacent DR4 stretch, and these variations were adequately explained by postulating recombination involving DR2 elements; hence, the DR2 array was deduced to be prone to recombination.

Abstract. Nagafuchi S,

Natto'', regarded as a traditional food, is made by fermenting boiled soybeans with Bacillus subtilis (natto), which is a natto-producing strain related to B. subtilis. Natto production is disrupted by bacteriophage infection of B. subtilis (natto); thus, it is necessary to control bacteriophage infection. A bacteriophage of B. subtilis (natto), PM1, was isolated during interrupted natto production in a factory. As PM1 was shown to have a long non-contractile tail in a morphological study, it was believed to belong to the family Siphoviridae. The genome of PM1 was shown to be a linear double-stranded DNA of approximately 50 kb. Based on the results of studies using restriction endonucleases, PM1 DNA was found to be circularly permuted, similar to bacteriophage DNA without definite ends (e.g. bacteriophage T4). The nucleotide sequence of a 1.1 kb segment of PM1 was determined and used to design a PCR assay. A 0.5 kb product was amplified from eight of ten bacteriophage isolates that infect B. subtilis (natto), and the nucleotide sequences of the PCR-amplified products were identical to those of PM1, suggesting that PM1-related bacteriophages are the most prevalent infectious agents associated with the disruption of natto production. The PCR method might be useful to detect PM1-related bacteriophages and will help to control bacteriophage infection.

A four-day-old Japanese Black Cattle calf presented with severe watery diarrhea, which lead to depression and bloody stool, followed by death, in Ishigaki Island, Japan on June 2007. Vibrio cholerae was isolated from the brain, heart, lungs and major organs in a pure culture. The strains were identified as serogroup O135. Immunohistochemical examination revealed a large number of V. choleraeo O135 antigens in the brain, lungs and thymus. The isolates do not produce cholera enterotoxin, while harbor hlyA and toxR genes. An epidemiological investigation showed that V. cholerae O135 was not isolated in environmental samples collected from the farm, whereas V. cholerae O14, O19, O27 and O170 were isolated from the seawater samples around coastal areas in remote islands respectively.