Two homologous Nicotiana tabacum genes NtTOM1 and NtTOM3 have been identified. These genes encode polypeptides with amino acid sequence similarity to Arabidopsis thaliana TOM1 and TOM3, which function in parallel to support tobamovirus multiplication. Simultaneous RNA interference against NtTOM1 and NtTOM3 in N. tabacum resulted in nearly complete inhibition of the multiplication of Tomato mosaic virus and other tobamoviruses, but did not affect plant growth or the ability of Cucumber mosaic virus to multiply. As TOM1 and TOM3 homologues are present in a variety of plant species, their inhibition via RNA interference should constitute a useful method for generating tobamovirus-resistant plants.

Heat-shock proteins (HSPs) act as molecular chaperones binding endogenous antigenic peptides and transporting them to major histocompatibility complexes. HSPs chaperone a broad repertoire of endogenous peptides including tumor antigens. For the immunotherapy of tumors, a strategy using HSPs may be more advantageous than other procedures because the identification of each tumorspecific antigen is not necessary. In this study, the efficacy of immunotherapy against minimal residual leukemia cells using HSP preparations was evaluated.HSP70 and GP96 were purified from syngeneic leukemia cell line A20 and immunized into BALB/c mice during the reconstitution period of the immune system after syngeneic bone marrow transplantation. In this procedure, all mice not immunized were dead within 60 days of A20 inoculation, whereas the survival times of HSP-immunized mice were significantly prolonged. In addition, the depletion of either CD4 ؉ or CD8 ؉ T lymphocyte significantly abrogated this efficacy, indicating that both CD4 ؉ and CD8 ؉ T lymphocytes were required for tumor cell rejection.

Summary. In the present study, we demonstrated that a close relationship exists between hepatitis C virus (HCV) infection of peripheral blood mononuclear cells (PBMCs) and cell-surface Fas expression in patients with hepatitis C, and showed the possibility of PBMCs apoptosis via a Fasmediated system. The expression of Fas on PBMCs was found by flowcytometric analysis to be significantly increased in these patients. In addition, the treatment of patients' PBMCs with anti-Fas antibody induced cell death, with nuclear condensation and fragmentation and cellular DNA fragmentation. These data indicate that the patients' PBMCs expressed a large amount of functional Fas on the cell surface and were susceptible to stimulation against Fas, causing apoptotic cell death. We then quantified the serumsoluble Fas ligand (sFasL), which was known to bind to Fas and induce the apoptotic signals into the sensitized cells.The patients' serum sFasL levels were significantly higher than those of normal subjects and showed a good negative correlation with their PBMC number. To demonstrate the correlation between Fas expression and HCV infection, nested reverse transcriptase polymerase chain reaction (RT-PCR) was performed to detect HCV RNA. Interestingly, HCV RNA was preferentially detected from Fas-positive cells but not from Fas-negative cells, which had been isolated from PBMCs by magnetic beads. These results suggest that HCV infection of PBMCs might induce Fas expression and additional stimulation such as sFasL might induce apoptosis in these Fas-expressing cells. These mechanisms, in addition to hypersplenism, may explain the decrease in the number of PBMCs observed in patients with chronic hepatitis C.

The influence of grain boundaries and intragrain defects on poly‐Si thin‐film transistors (TFTs) was investigated by examining the crystallinity of poly‐Si films formed by solid phase crystallization (SPC) and excimer laser annealing (ELA), and the electrical characteristics of transistors fabricated on the poly‐Si films were examined. The increase in grain size by SPC improves field effect mobility (μFE) due to the increase in the emission current over the potential barrier height at the grain boundary. The decrease in intragrain defect densities by an oxide thinning process improves the μFE, threshold voltage (V th) and subthreshold voltage swing (S). On the contrary, in spite of the small grain size of 800 Å, poly‐Si TFTs fabricated by ELA exhibit good characteristics with a high μFE, low V th and low S, and good uniformity. It is found that since the realization of excellent performance and good uniformity in poly‐Si TFTs depends on a low trap state density at the grain boundaries and a low intragrain defect density, poly‐Si films formed by ELA are well suited for the application to poly‐Si TFT liquid crystal display with peripheral integrated circuits.

The virulence factor of Melon necrotic spot virus (MNSV), a virus that induces systemic necrotic spot disease on melon plants, was investigated. When the replication protein p29 was expressed in N. benthamiana using a Cucumber mosaic virus vector, necrotic spots appeared on the leaf tissue. Transmission electron microscopy revealed abnormal mitochondrial aggregation in these tissues. Fractionation of tissues expressing p29 and confocal imaging using GFP-tagged p29 revealed that p29 associated with the mitochondrial membrane as an integral membrane protein. Expression analysis of p29 deletion fragments and prediction of hydrophobic transmembrane domains (TMDs) in p29 showed that deletion of the second putative TMD from p29 led to deficiencies in both the mitochondrial localization and virulence of p29. Taken together, these results indicated that MNSV p29 interacts with the mitochondrial membrane and that p29 may be a virulence factor causing the observed necrosis.

A 49-year-old man presented a progressive swelling and induration of the skin resulting in flexion contracture. He had a history of two tick bites at the age of 17 and 47 years. Serum anti-Borrelia-burgdorferi antibody was positive; isolation of B. burgdorferi from the skin lesion was unsuccessful. He had eosinophilia (white blood cells 8,300/μl, 33% eosinophils) and hypergammaglobulinemia. The diagnosis of Shulman syndrome (eosinophilic fasciitis) from clinical and histological findings was established. A part of the flagellin gene of B. burgdorferi was detected in a skin biopsy sample by using the polymerase chain reaction method. To the best of our knowledge, this is the first report of detection of B.-burgdorferi-specific DNA from a skin sample of Shulman syndrome.

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A plant integral membrane protein TOM1 is involved in the multiplication of Tomato mosaic virus (ToMV). TOM1 interacts with ToMV replication proteins and has been suggested to tether the replication proteins to the membranes where the viral RNA synthesis takes place. We have previously demonstrated that inactivation of TOM1 results in reduced ToMV multiplication. In the present study, we show that overexpression of TOM1 in tobacco also inhibits ToMV propagation. TOM1 overexpression led to a decreased accumulation of the soluble form of the replication proteins and interfered with the ability of the replication protein to suppress RNA silencing. The reduced accumulation of the soluble replication proteins was also observed in a silencing suppressor-defective ToMV mutant. Based on these results, we propose that RNA silencing suppression is executed by the soluble form of the replication proteins and that efficient ToMV multiplication requires balanced accumulation of the soluble and membrane-bound replication proteins.