Comparison of OspA Serotypes for Borrelia burgdorferi Sensu Lato from Japan,Europe and North America

Sixty-one Borrelia burgdorferi sensu lato strains from various sources (ticks, human, and wild animals) in Japan and two strains from ticks in Far Eastern Russia were classified on the basis of reactivity with 16 monoclonal antibodies (mAb) to outer surface protein A (OspA) and by DNA-DNA hybridization assay. Eleven OspA serotypes (J1 to J11) were recognized among the Japanese and the Far East Russian isolates (serotypes J1 to J9 were identified as B. garinii, serotype J10 was identified as B. afzelii, and serotype J11 corresponded to B. japonica), whereas 7 OspA serotypes for North American and European isolates previously reported (Bettina Wilske et al, J. Clin. Microbiol. 31:340-350, 1993) were not observed except for OspA serotype 2 which showed identical reactivity with OspA serotype J10. This finding provides helpful information for understanding the geographical distribution of Lyme disease borrelia and the development of vaccine and diagnostic tests. In conclusion: 1. B. burgdorferi sensu stricto has not been observed in Japan, 2. Japanese B. afzelii isolates are closely related to those from Europe, 3. B. garinii isolates from Japan are highly heterogeneous and apparently different from European B. garinii isolates.     

Distribution of Vacuolar H+-Pyrophosphatase and a Membrane Integral Protein in a Variety of Green Plants

Vacuolar membranes isolated from several species including fernand moss exhibited pyro-phosphate-dependent H⁺ transport activity.On immunoblot analysis, H⁺ -pyrophosphatase was detected inthe vacuolar membranes. A membrane integral protein of 23,000daltons was not found in the membranes of Chara, Conocephalum,or Kalanchoë. Thus, H⁺-pyrophosphatase may be a universalenzyme among green plants, but the 23-kDa protein is not a commonprotein of central vacuoles. (Received September 10, 1993; Accepted November 29, 1993)     

Enigmatic double-stranded RNA in Japonica rice

We have found a linear, 16 kb, double-stranded RNA (dsRNA) in symptomless Japonica rice (Oryza sativa L.) that is not found in Indica rice (Oryza sativa L.). The dsRNA was detected in every tissue and at every developmental stage, and its copy number was approximately constant (about 20 copies/cell). Double-stranded RNA was also detected in two strains of Oryza rufipogon (an ancestor of O. sativa). Hybridization experiments indicated that the dsRNA of O. rufipogon was homologous but not identical to that of O. sativa. The sequence of about 13.2 kb of the dsRNA was determined and two open reading frames (ORFs) were found. The larger ORF (ORF B) was more than 12 351 nucleotides long and encoded more than 4 117 amino acid residues.     

Cytokine regulation of cell-to-cell interactions in lymphokine-activated killer cell cytotoxicity in vitro

The permanent pancreas carcinoma cell line, PCI-24, was developed in order to analyse cytokine regulation on pancreas carcinoma and lymphokine-activated killer (LAK) cell interaction. PCI cells expressed ICAM-1 and HLA-ABC, but not HLA-DR antigens. PCI cells showed augmented ICAM-1 and HLA-ABC expression when incubated with interferon (IFN) and tumour necrosis factor . A similar but weak augmentary effect on the HLA-ABC and ICAM-1 surface expression was seen with interleukin-1 treatment. Natural attachment of LAK to PCI cells was augmented by recombinant IFN in close association with ICAM-1 up-regulation on PCI cells. In addition, natural attachment was significantly inhibited by anti-LFA-1 and anti-ICAM-1 antibody treatments. Cytotoxicity of the LAK cells against PCI cells was also significantly inhibited with the same treatment. Thus, the attachment of LAK cells to PCI cells through LFA-1/ICAM-1 molecules appeared to be essential for the cytotoxicity for PCI cells. Pretreatment of PCI cells, but not of LAK cells, with IFN or other cytokines resulted in a decrease of susceptibility for LAK cell cytotoxicity. The decreased susceptibility inversely correlated with HLA-ABC expression on the PCI cells. The collective evidence indicates that, although LAK cell attachment to pancreas carcinoma cells through the LFA-1/ICAM-1 molecule is augmented by IFN, IFN treatment of pancreas carcinoma cells reduces LAK cell cytotoxicity possibly through an increase in HLA-ABC or a regulation of molecules closely associated to HLA-ABC expression.     

Genomic Analysis of Borrelia japonica Sp. Nov. Isolated from Ixodes ovatus in Japan

Genetic characteristics of 12 Borrelia isolates from the tick, Ixodes ovatus, I. persulcatus, and the rodent, Apodemus speciosus ainu, in Japan were compared to members of the three genospecies of Borrelia burgdorferi sensu lato; B. burgdorferi sensu stricto, B. garinii and group VS461. The methods used in this study were the quantitative microplate DNA hybridization assay and restriction fragment length polymorphism (RFLP) analyses of the flagellin structural genes and the 16S rRNA genes. The six isolates from I. persulcatus and A. speciosus ainu were identified as genospecies B. garinii using RFLP analysis of the flagellin and 16S rRNA genes. In contrast, RFLP analysis of the six isolates from I. ovatus indicated that they were different from the three reported genospecies. DNA homology studies confirmed the RFLP results. The six isolates from I. ovatus had DNA homologies ranging from 85 to 99%, whereas DNA relatedness of the I. ovatus isolate with strains belonging to the three genospecies was 50 to 64%. These results suggest that the strains isolated from I. ovatus in Japan differ from the three genospecies and should be classified as a new genospecies of B. burgdorferi sensu lato. We propose that strains isolated from I. ovatus should be classified as B. japonica sp. nov.     

Molecular phylogeny based on the κ-casein and cytochrome b sequences in the mammalian suborder Ruminantia

Nucleotide sequences for the -casein precursor proteins have been determined from the genomic DNAs or hair roots of the Ruminantia. The coding regions, exons 2, 3, and 4, were amplified separately via the three kinds of PCRs and then directly sequenced. The primers were designed from the sequence of bovine -casein gene; they were applicable for the amplification of the -casein genes from the 13 species in the Ruminantia except exon 2 of the lesser mouse deer. These results permitted an easy phylogenetic analysis based on the sequences of an autosomal gene. A phylogenetic tree was constructed from the mature K-casein sequences and compared with the tree of the cytochrome b genes which were sequenced from the same individuals. The Cervidae (sika deer, Cervus nippon) were separated from the branch of the Bovidae on the tree of -casein genes with a relatively high confidence level of the bootstrap analysis, but included in the branch of the Bovidae on the tree of cytochrome b genes. The -casein tree indicated a monophyly of the subfamily Caprinae, although the internal branches were uncertain in the Caprinae. The tree based on the nucleotide sequences of cytochrome b genes clearly showed the relationships of the closely related species in the genus Capricornis consisting of serow (C. smatorensis), Japanese serow (C. crispus), and Formosan serow (C. swinhoei). These results would be explained by the difference of resolving power between the -casein and the cytochrome b sequences. Correspondence to: K. Chikuni