Induction of antiviral responses by acibenzolar-s-methyl against cucurbit chlorotic yellows virus in Melon

Cucurbit chlorotic yellows virus (CCYV) (family Closteroviridae, genus Crinivirus) is an emerging virus which causes severe diseases on melon (Cucumis melo) plants. CCYV-infected melon plants display yellowing, mottling, chlorosis, or chlorotic spots on leaves. To develop a new control strategy, the potential for 1,2,3-benzothiadiazole-7-thiocarboxylic acid-S-methyl-ester (ASM) to suppress CCYV infection was evaluated. ASM treatment on melon plants greatly increased the expression levels of pathogenesis-related 1a gene, a marker gene for systemic acquired resistance. ASM treatment on melon plants before inoculation of CCYV suppressed systemic symptoms and decreased CCYV accumulation. ASM treatment on melon even after inoculation of CCYV reduced disease severity and accumulation levels of CCYV. The results show the potential for ASM treatment on attenuation of the CCYV disease symptoms.

RCY1-mediated resistance to Cucumber mosaic virus is regulated by LRR domain-mediated interaction with CMV(Y) following degradation of RCY1

RCY1, which encodes a coiled coil nucleotide-binding site leucine-rich repeat (LRR) class R protein, confers the hypersensitive response (HR) to a yellow strain of Cucumber mosaic virus (CMV[Y]) in Arabidopsis thaliana. Nicotiana benthamiana transformed with hemagglutinin (HA) epitope-tagged RCY1 (RCY1-HA) also exhibited a defense response accompanied by HR cell death and induction of defense-related gene expression in response to CMV(Y). Following transient expression of RCY1-HA by agroinfiltration, the defense reaction was induced in N. benthamiana leaves infected with CMV(Y) but not in virulent CMV(B2)-infected N. benthamiana leaves transiently expressing RCY1-HA or CMV(Y)-infected N. benthamiana leaves transiently expressing HA-tagged RPP8 (RPP8-HA), which is allelic to RCY1. This result suggests that Arabidopsis RCY1-conferred resistance to CMV(Y) could be reproduced in N. benthamiana leaves in a gene-for-gene manner. Expression of a series of chimeric constructs between RCY1-HA and RPP8-HA in CMV(Y)-infected N. benthamiana indicated that induction of defense responses to CMV(Y) is regulated by the LRR domain of RCY1. Interestingly, in CMV(Y)-infected N. benthamiana manifesting the defense response, the levels of both RCY1 and chimeric proteins harboring the RCY1 LRR domain were significantly reduced. Taken together, these data indicate that the RCY1-conferred resistance response to CMV(Y) is regulated by an LRR domain-mediated interaction with CMV(Y) and seems to be tightly associated with the degradation of RCY1 in response to CMV(Y).

Infection dynamics in viral spread and interference under the synergism between Cucumber mosaic virus and Turnip mosaic virus

Mixed infection of Cucumber mosaic virus (CMV) and Turnip mosaic virus (TuMV) induced more severe symptoms on Nicotiana benthamiana than single infection. To dissect the relationships between spatial infection patterns and the 2b protein (2b) of CMV in single or mixed infections, the CMV vectors expressing enhanced green fluorescent or Discosoma sp. red fluorescent proteins (EGFP [EG] or DsRed2 [Ds], respectively were constructed from the same wild-type CMV-Y and used for inoculation onto N. benthamiana. CMV2-A1 vector (C2-A1 [A1]) has a functional 2b while CMV-H1 vector (C2-H1 [H1]) is 2b deficient. As we expected from the 2b function as an RNA silencing suppressor (RSS), in a single infection, A1Ds retained a high level of accumulation at initial infection sites and showed extensive fluorescence in upper, noninoculated leaves, whereas H1Ds disappeared rapidly at initial infection sites and could not spread efficiently in upper, noninoculated leaf tissues. In various mixed infections, we found two phenomena providing novel insights into the relationships among RSS, viral synergism, and interference. First, H1Ds could not spread efficiently from vasculature into nonvascular tissues with or without TuMV, suggesting that RNA silencing was not involved in CMV unloading from vasculature. These results indicated that 2b could promote CMV to unload from vasculature into nonvascular tissues, and that this 2b function might be independent of its RSS activity. Second, we detected spatial interference (local interference) between A1Ds and A1EG in mixed infection with TuMV, between A1Ds (or H1Ds) and TuMV, and between H1Ds and H1EG. This observation suggested that local interference between two viruses was established even in the synergism between CMV and TuMV and, again, RNA silencing did not seem to contribute greatly to this phenomenon.

Role of transcription factors in small intestinal ischemia-reperfusion injury and tolerance induced by ischemic preconditioning

BACKGROUND

Small intestinal ischemia-reperfusion (I/R) injury, a clinically important condition, induces severe organ damage. Ischemic preconditioning (IPC) produces tolerance to long-term I/R by inducing a short-term I/R. Herein, we have examined the reduction in the extent of injury by IPC.

METHODS

Small intestinal I/R injury was induced in rats by clamping the superior mesenteric artery (SMA) for 30 minutes followed by reperfusion for various 30 minutes. The IPC + I/R group underwent a short-term I/R (IPC) prior to long-term I/R. Nuclear factor-κB (NF-κB) activity was analyzed by an electrophoretic mobility shift assay and cytokine mRNA levels, by reverse transcription-polymerase chain reaction. Apoptosis-related genes were analyzed by Western blotting and immunohistochemistry, and apoptotic cells, by TUNEL staining.

RESULTS

The animals were subjected to 30 minutes of ischemia followed by 30 minutes of reperfusion. NF-κB activity increased in the I/R group and decreased in the IPC + I/R group. The IPC + I/R group showed decreased cytokine in mRNA levels. Expression of the proapoptotic gene caspase-3 was increased in the I/R and decreased in the IPC + I/R group. Expression of the antiapoptotic gene Bcl-xL was increased in the IPC + I/R group. The number of apoptotic cells was increased in the I/R and decreased in the IPC + I/R group.

CONCLUSION

Small intestinal I/R injury was reduced by IPC produced by clamping the SMA; thus, IPC may have potential clinical applications in the future.

The influence of RNA-dependent RNA polymerase 1 on potato virus Y infection and on other antiviral response genes

The gene encoding RNA-dependent RNA polymerase 1 (RDR1) is involved in basal resistance to several viruses. Expression of the RDR1 gene also is induced in resistance to Tobacco mosaic virus (TMV) mediated by the N gene in tobacco (Nicotiana tabacum cv. Samsun NN) in an incompatible hypersensitive response, as well as in a compatible response against Potato virus Y (PVY). Reducing the accumulation of NtRDR1 transcripts by RNA inhibition mediated by transgenic expression of a double-stranded RNA hairpin corresponding to part of the RDR1 gene resulted in little or no induction of accumulation of RDR1 transcripts after infection by PVY. Plants with lower accumulation of RDR1 transcripts showed much higher accumulation levels of PVY. Reduced accumulation of NtRDR1 transcripts also resulted in lower or no induced expression of three other antiviral, defense-related genes after infection by PVY. These genes encoded a mitochondrial alternative oxidase, an inhibitor of virus replication (IVR), and a transcription factor, ERF5, all involved in resistance to infection by TMV, as well as RDR6, involved in RNA silencing. The extent of the effect on the induced NtIVR and NtERF5 genes correlated with the extent of suppression of the NtRDR1 gene.

Impact of a defective RNA 3 from cucumber mosaic virus on helper virus infection dynamics

D RNA 3Yalpha (D3Yalpha), a defective (D) RNA 3 derived from the Y strain of cucumber mosaic virus (CMV-Y), was further characterized in combination with different helper viruses in the genus Cucumovirus. Interestingly, Nicotiana benthamiana plants inoculated with CMV-D8 and D3Yalpha developed systemic symptoms which were different from those induced by CMV-D8. To elucidate the potential effects of D RNA 3 on virus infection on the basis of the original combination of CMV-Y and D3Yalpha, a point mutation was made in the coat protein gene, which determined symptoms, of either CMV-Y RNA 3 (Y3) or D3Yalpha. Symptoms induced on N. benthamiana and N. tabacum plants, and semi-quantitative RT-PCR revealed that the ratio of RNA 3 to D RNA 3 was associated with the differences of symptoms in the leaf tissues. Furthermore, analysis of in situ hybridization suggested that there were spatial effects between coat proteins of Y3 and D3Yalpha in the infected leaves.

Characterization of a defective RNA derived from RNA 3 of the Y strain of cucumber mosaic virus

A defective (D) RNA 3 naturally generated from the Y strain of cucumber mosaic virus (CMV-Y) was characterized using a biologically active cDNA clone. Sequencing of the clone revealed that the D RNA 3, named D RNA 3Yalpha, was derived from CMV-Y RNA 3 and contained a 10 nt deletion in the 5' untranslated region and a 162 nt deletion within the 3a open reading frame. Co-inoculation of D RNA 3Yalpha with CMV-Y derived from in vitro transcripts facilitated propagation of CMV-Y containing D RNA 3Yalpha in Nicotiana benthamiana or Nicotiana tabacum plants. CMV-Y, however, did not produce deletion mutants upon serial mechanical passages in the plants.

Prevalence of hepatitis C virus infection in cases of B-cell lymphoma in Japan

AIMS

To determine the prevalence of hepatitis C virus (HCV) infection in B-cell lymphoma in Japan. HCV infection and type II (monoclonal IgM) cryoglobulinaemia (CG) may be involved in the pathogenesis of low-grade B-cell lymphoma (ML) in southern Europe.

METHODS AND RESULTS

Forty-five (11.3%) of 400 B-cell ML cases were HCV antibody (Ab) positive, which was significantly (P < 0.01) higher than the blood donors (2.5%). Among them, 28 diffuse large B-cell lymphoma (DLBCL) cases were included. In the primary sites, 10 (47.6%) of 21 splenic DLBCL and seven (23.3%) of 30 gastric DLBCL were HCV Ab positive, which were significantly (P < 0.05) higher than the myeloma cases (4.9%). HCV infection was rarely (4.2%) detected in 24 lymphoplasmacytic and salivary gland low-grade B-cell ML cases. Type II CG was detected in one myeloma case (3.5%) of 29 HCV+ B-cell ML. By real-time polymerase chain reaction, HCV RNA was detected in fresh tumour tissues of all 11 B-cell ML cases examined. Lymphoma cells were positive for the envelope HCV non-structural (NS)3 and envelope (E2) proteins in six of eight examined B-cell ML cases.

CONCLUSIONS

The rare incidence of type II CG is characteristic of Japanese HCV+ ML patients and may influence the low incidence of low-grade B-cell ML. HCV infection may play a role in lymphomagenesis of splenic and gastric DLBCL.

The wide distribution of endornaviruses, large double-stranded RNA replicons with plasmid-like properties

The International Committee on Taxonomy of Viruses (ICTV) recently accepted Endornavirus as a new genus of plant dsRNA virus. We have determined the partial nucleotide sequences of the RNA-dependent RNA polymerase regions from the large dsRNAs (about 14 kbp) isolated from barley (Hordeum vulgare), kidney bean (Phaseolus vulgaris), melon (Cucumis melo), bottle gourd (Lagenaria siceraria), Malabar spinach (Basella alba), seagrass (Zostera marina), and the fungus Helicobasidium mompa. Phylogenetic analyses of these seven dsRNAs indicate that these dsRNAs are new members of the genus Endornavirus that are widely distributed over the plant and fungal kingdoms.

Identification of Ki23819, a highly potent inhibitor of kinase activity of mutant FLT3 receptor tyrosine kinase

Constitutively active internal tandem duplication (ITD) in the juxtamembrane domain of Fms-like tyrosine kinase 3 (FLT3), a type III receptor tyrosine kinase, is the most common molecular defect associated with acute myeloid leukemia. Its presence confers a poor outcome in patients with acute myeloid leukemia who receive conventional chemotherapy. FLT3-ITD has therefore been considered to be an attractive molecular target for a novel therapeutic modality. We describe here the identification and characterization of Ki23819 as a novel FLT3 inhibitor. Ki23819 suppressed proliferation and induced apoptosis of FLT3-ITD-expressing human leukemia cell lines. The growth-inhibitory effect of Ki23819 on MV4-11 cells was superior to that of SU11248, another FLT3 inhibitor (IC(50)<1 vs 3-10 nM). Ki23819 inhibited the autophosphorylation of FLT3-ITD more efficiently than that of wild-type FLT3. FLT3-ITD-dependent activation of the downstream signaling proteins ERK and STAT5 was also inhibited within similar concentration ranges. Thus, Ki23819 is a potent in vitro inhibitor of FLT3.

Multiple organ failure caused by end-stage liver disease successfully treated with living donor liver transplantation using perioperative percutaneous cardiopulmonary support: a case report

A 54-year-old female diagnosed with primary biliary cirrhosis (PBC) 10 years earlier was referred for a living donor liver transplant (LDLT). During her workup, she developed pulmonary edema and respiratory failure due to aspiration pneumonia, which required artificial ventilation. The PaO2/FiO2 (P/F) ratio at that time was 60. Although continuous hemodiafiltration (CHDF) and plasma exchange (PE) were initiated, improvement in the P/F ratio was limited to 133. As transplantation was the only approach to save this patient, we performed LDLT using a right lobe graft aided by percutaneous cardiopulmonary support (PCPS). The graft weight was 650 g and the graft weight/recipient weight ratio was 1.6%. During LDLT, the patient's cardiopulmonary function was stable with PCPS, and the surgical procedure was completed without complications. Following the surgery, she continued to have high-end inspiratory pressure and progressed to the chronic phase of adult respiratory distress syndrome (ARDS). We treated her with low-dose steroid therapy and she improved gradually. The patient was weaned off mechanical ventilation and was discharged approximately 25 weeks after LDLT. In the condition of cardiac or respiratory failure, cadaveric liver transplantation using plasmapheresis is contraindicated because of the associated high mortality rate. Our case suggests that if infections are controlled, a patient with multiple organ failure (MOF) due to end-stage liver disease might be successfully treated with LDLT aided by plasmapheresis and PCPS.

Solid serous cystadenoma of the pancreas: MR imaging with pathologic correlation

We report a case of solid type serous cystadenoma of the pancreas. Computed tomographic and magnetic resonance (MR) images showed a hypervascular solid tumor that was difficult to differentiate from endocrine tumor of the pancreas. However, the tumor showed marked hyperintensity similar to that of hepatic cyst on MR cholangiopancreatography, indicating not a solid but rather a cystic nature. MR cholangiopancreatography (heavily T2-weighted image) is quite useful for clearly differentiating solid from cystic tumors.

Spatial analysis for exclusive interactions between subgroups I and II of Cucumber mosaic virus in cowpea

The dynamics of virus interference in Cucumber mosaic virus (CMV) infection in cowpea were investigated by tissue-blotting and in situ hybridization. Using co-inoculation assays, we discovered that spatial competition between CMV-LE (subgroup I) and CMV-m2 (subgroup II) occurred in the inoculated leaves. Interestingly, competitive interactions between the two viruses also could be observed in the non-inoculated upper leaf tissues of the plants. Furthermore, the pattern of exclusive distribution was observed between challenge and protecting viruses in the serially inoculated leaves. Taken together, it is suggested that the dynamics of competitive interactions between the two subgroups could be characterized by exclusive infection and multiplication of the individual viruses in cowpea plants.

Competition between wild-type virus and a reassortant from subgroups I and II of CMV and activation of antiviral responses in cowpea

To investigate the interactions between RNA3 and RNA4 from subgroups I and II in mixed infections, accumulation of CMV RNA were analyzed. In the mixed inoculation assays with CMV-LE (LE, subgroup I) and a reassortant LLm consisting of RNA1 and RNA2 from LE, and RNA3 from CMV-m2 (m2, subgroup II), LE RNA3 and RNA4 could systemically spread in the plants, whereas those of m2 could not. Furthermore, accumulation of virus short RNA and a cowpea-encoded RNA-directed RNA polymerase gene (VuRdRP1) mRNA were found in the plants, suggesting that VIGS and/or distinct antiviral responses (was) were activated by infection with CMV.

Reverse seroconversion of hepatitis B virus after hematopoietic stem cell transplantation

Hepatitis B virus (HBV) reactivation in patients previously positive for hepatitis B surface antibody (HBsAb), so-called reverse seroconversion, has been considered to be a rare complication after hematopoietic stem cell transplantation (HSCT). We experienced two patients who developed reverse seroconversion among nine who were HBsAb positive and Hepatitis B core antibody (HBcAb) positive before HSCT; one after autologous bone marrow transplantation (BMT) and another after allogeneic peripheral blood stem cell transplantation (PBSCT). We reviewed the literature and considered that reverse seroconversion of HBV after HSCT is not uncommon among HBsAb positive recipients. The use of corticosteroids, the lack of HBsAb in donor, and a decrease in serum HBsAb and HBcAb levels may predict reverse seroconversion after HSCT.

Carcinoma of the colon metastatic to the lower gingiva

A case of carcinoma of the colon that metastasized to the lower gingiva is described. The patient who had carcinoma of the colon developed a proliferating lesion at the site of a recent tooth extraction. A few days later, the primary site of the malignancy appeared. The clinical features in such cases were reviewed in studies by others, most of which were of oral and dental surgery. Thus, because of our case, gastroenterologists should consider the possibility of gingival metastasis from malignant disease such as colorectal cancer.