[Lung cancer reveal by mandibular metastasis: a case at the Centre of Consultation and Dental Treatment Dental of Casablanca (CCDTC)]. / Métastase mandibulaire révélatrice d'un cancer du poumon. A propos d'un cas au Centre de Consultation et de Traitement Dentaires de Casablanca (CCTDC).

Metastatic tumors result from hematogenous spread through a tumor located at a distance. All these tumors represent about 1% of malignant tumors of the oral cavity (1). The most common location is the mandible (70%), more rarely maxillary (2). The most frequently encountered tumors are carcinomas or adenocarcinomas of mammary origin, brocho-lung, prostate, kidney or another. This study reports the case of a 46 year-old man, who presented for consultation with a low left laterofacial swelling, paresthesia lip and chin straight associated with pain at the lower edge of the mandible evolving for 2 months. The patient is known to take alcohol and tobacco for 20 years. The panoramic radiograph showed radiolucent image with blurred boundaries at the lower right premolar region. Dentascan revealed an irregular osteolytic lesion with rupture of the table lingual. After surgical exploration, the pathological examination is for a well-differentiated and invasive adenocarcinoma of the mandible. Extension work-up shows the presence of a tumor right lung, a lytic lesion at the 8th costal arch, the fourth dorsal vertebra and another location in fibula. The surgical exploration of pulmonary was performed and confirmed the pulmonary primitive localization of adenocarcinoma.

Rapid screening of RNA silencing suppressors by using a recombinant virus derived from beet necrotic yellow vein virus.

To counteract plant defence mechanisms, plant viruses have evolved to encode RNA silencing suppressor (RSS) proteins. These proteins can be identified by a range of silencing suppressor assays. Here, we describe a simple method using beet necrotic yellow vein virus (BNYVV) that allows a rapid screening of RSS activity. The viral inoculum consisted of BNYVV RNA1, which encodes proteins involved in viral replication, and two BNYVV-derived replicons: rep3-P30, which expresses the movement protein P30 of tobacco mosaic virus, and rep5-X, which allows the expression of a putative RSS (X). This approach has been validated through the use of several known RSSs. Two potential candidates have been tested and we show that, in our system, the P13 protein of burdock mottle virus displays RSS activity while the P0 protein of cereal yellow dwarf virus-RPV does not.

First Report on the Natural Occurrence of Beet chlorosis virus in Poland.

Yellowing symptoms on sugar beet (Beta vulgaris L.) are caused by several viruses, especially those belonging to the genus Polerovirus of the family Luteoviridae, including Beet mild yellowing virus (BMYV) and Beet western yellows virus (BWYV), and recently, a new species, Beet chlorosis virus (BChV), was reported (2). To identify Polerovirus species occurring in beet crops in Poland and determine their molecular variability, field surveys were performed in the summer and autumn of 2005. Leaves from symptomatic beet plants were collected at 26 localities in the main commercial sugar-beet-growing areas in Poland that included the Bydgoszcz, Kutno, Lublin, Poznan, Olsztyn, and Warszawa regions. Enzyme-linked immunosorbent assay (ELISA) tests (Loewe Biochemica GmbH, Sauerlach, Germany) detected poleroviruses in 23 of 160 samples (approximately 20 samples from each field). Multiplex reverse-transcription polymerase chain reaction (RT-PCR) (1) (GE Healthcare S.A.-Amersham Velizy, France) confirmed the presence of poleroviruses in 13 of 23 samples. Nine of twenty sugar beet plants gave positive reactions with BChV-specific primers and three with primers specific to the BMYV P0 protein. Two isolates reacted only with primer sets CP+/CP, sequences that are highly conserved for all beet poleroviruses. Leaf samples collected from three plants infected with BChV were used as inoculum sources for Myzus persicae in transmission tests to suitable indicator plants including sugar beet, red beet (Beta vulgaris L. var. conditiva Alef.), and Chenopodium capitatum. All C. capitatum and beet plants were successfully infected with BChV after a 48-h acquisition access period and an inoculation access period of 3 days. Transmission was confirmed by the presence of characteristic symptoms and by ELISA. Amino acid sequences obtained from each of four purified (QIAquick PCR Purification kit, Qiagen S.A., Courtaboeuf, France) RT-PCR products (550 and 750 bp for CP and P0, respectively) were 100% identical with the CP region (GenBank Accession No. AAF89621) and 98% identical with the P0 region (GenBank Accession No. NP114360) of the French isolate of BChV. To our knowledge, this is the first report of BChV in Poland. References: (1) S. Hauser et al. J. Virol. Methods 89:11, 2000. (2) M. Stevens et al. Mol. Plant Pathol. 6:1, 2005.

Cell-to-cell movement of beet necrotic yellow vein virus: I. Heterologous complementation experiments provide evidence for specific interactions among the triple gene block proteins.

Cell-to-cell movement of beet necrotic yellow vein virus (BNYVV) requires three proteins encoded by a triple gene block (TGB) on viral RNA 2. A BNYVV RNA 3-derived replicon was used to express movement proteins to functionally substitute for the BNYVV TGB proteins was tested by coinoculation of TGB-defective BNYVV with the various replicons to Chenopodium quinoa. Trans-heterocomplementation was successful with the movement protein (P30) of tobacco mosaic virus but not with the tubule-forming movement proteins of alfalfa mosaic virus and grapevine fanleaf virus. Trans-complementation of BNYVV movement was also observed when all three TGB proteins of the distantly related peanut clump virus were supplied together but not when they were substituted for their BNYVV counterparts one by one. When P30 was used to drive BNYVV movement in trans, accumulation of the first TGB protein of BNYVV was adversely affected by null mutations in the second and third TGB proteins. Taken together, these results suggest that highly specific interactions among cognate TGB proteins are important for their function and/or stability in planta.

P42 movement protein of Beet necrotic yellow vein virus is targeted by the movement proteins P13 and P15 to punctate bodies associated with plasmodesmata.

Cell-to-cell movement of Beet necrotic yellow vein virus (BNYVV) is driven by a set of three movement proteins--P42, P13, and P15--organized into a triple gene block (TGB) on viral RNA 2. The first TGB protein, P42, has been fused to the green fluorescent protein (GFP) and fusion proteins between P42 and GFP were expressed from a BNYVV RNA 3-based replicon during virus infection. GFP-P42, in which the GFP was fused to the P42 N terminus, could drive viral cell-to-cell movement when the copy of the P42 gene on RNA 2 was disabled but the C-terminal fusion P42-GFP could not. Confocal microscopy of epidermal cells of Chenopodium quinoa near the leading edge of the infection revealed that GFP-P42 localized to punctate bodies apposed to the cell wall whereas free GFP, expressed from the replicon, was distributed uniformly throughout the cytoplasm. The punctate bodies sometimes appeared to traverse the cell wall or to form pairs of disconnected bodies on each side. The punctate bodies co-localized with callose, indicating that they are associated with plasmodesmata-rich regions such as pit fields. Point mutations in P42 that inhibited its ability to drive cell-to-cell movement also inhibited GFP-P42 punctate body formation. GFP-P42 punctate body formation was dependent on expression of P13 and P15 during the infection, indicating that these proteins act together or sequentially to localize P42 to the plasmodesmata.

Chimeric vector construction for higher-plant transformation.

A chimeric vector pKR612B1 was developed containing the neomycin phosphotransferase (APH) gene from the Tn5 transposon under the control of the gene VI promoter of cauliflower mosaic virus (CaMV), and was used to transform higher plant protoplasts. Plasmid pDOB612, the parental vector of pKR612B1, has two unique restriction sites, SmaI and BamHI, positioned just downstream of the CaMV gene VI promoter sequence. These unique cloning sites can be used for any kind of gene insertion into this vector. Using the polyethylene glycol transformation procedure, a large number of turnip and tobacco protoplasts were transformed and proved to be resistant to kanamycin (Km). From tobacco protoplasts whole Km-resistant plants were regenerated and shown to contain the integrated foreign gene. APH activity was detected in both transformed calli and in regenerated plants. DNA from transformed clones was analysed by Southern blot hybridization, showing the presence of the Tn5-derived gene.

Subcellular localization of the Triple Gene Block movement proteins of Beet necrotic yellow vein virus by electron microscopy.

The Triple Gene Block proteins TGBp1, TGBp2, and TGBp3 of Beet necrotic yellow vein virus (BNYVV) are required for efficient cell-to-cell spread of the infection. The TGB proteins can drive cell-to-cell movement of BNYVV in trans when expressed from a co-inoculated BNYVV RNA 3-based 'replicon'. TGBp2 and TGBp3 expressed from the replicon were nonfunctional in this assay if they were fused to the green fluorescent protein (GFP), but addition of a hemagglutinin (HA) tag to their C-termini did not incapacitate movement. Immunogold labeling of ultrathin sections treated with HA-specific antibodies localized TGBp2-HA and TGBp3-HA to what are probably structurally modified plasmodesmata (Pd) in infected cells. A similar subcellular localization was observed for TGBp1. Large gold-decorated membrane-rich bodies containing what appear to be short fragments of endoplasmic reticulum were observed near the cell periphery. The modified gold-decorated Pd and the membrane-rich bodies were not observed when the TGB proteins were produced individually in infections using the Tobacco mosaic virus P30 protein to drive cell-to-cell movement, indicating that these modifications are specific for TGB-mediated movement.

Visualisation of transgene expression at the single protoplast level.

Protoplasts are currently used to study the expression of genes following transformation. Expression is followed on a population of protoplasts after total protein extraction by conventional western blotting or measure of the enzymatic activity of the transgenic protein. We describe here a new method, called protoplast printing, allowing easy detection of the fraction of cells expressing a certain protein within a population of protoplasts. It consists of immobilization of the protoplast proteins on a nitrocellulose filter, so as to retain the outlines of the cell, followed by immunological detection of the protein of interest. The only special requirement is an antibody specific for the protein. We have studied the expression of the BNYVV coat protein after electroporation of Chenopodium quinoa protoplasts with viral RNAs, and the expression of the NPT II gene in protoplasts isolated from transgenic tobacco plants as well as after direct transfer of plasmid DNA into tobacco protoplasts. In both cases - infection with viral RNAs and transformation with plasmid DNA - expressing and non-expressing cells can be distinguished as early as 12h after transfer of the transgenes.

Efficient cell-to-cell movement of beet necrotic yellow vein virus requires 3' proximal genes located on RNA 2.

RNA 2 of beet necrotic yellow vein virus (BNYVV) carries six open reading frames. The four 3' proximal frames encode the proteins P42, P13, P15, and P14. The first three species present homologies to proteins encoded by three overlapping open reading frames (the triple gene block) in potexviruses, carlaviruses, and barley stripe mosaic virus. P14 does not display homology with other known plant viral proteins. The functions of P42, P13, P15, and P14 were investigated by site-directed mutagenesis. Full-length transcripts of wild-type BNYVV RNAs 1 and 2 were infectious when coinoculated to protoplasts or leaves of Chenopodium quinoa. RNA 2 transcripts in which P42, P13, and P15 were prematurely terminated by frameshift mutations replicated in protoplasts (when inoculated with wild-type RNA 1) but were not infectious to leaves, indicating that the triple gene block proteins of BNYVV are essential for viral cell-to-cell spread. Mutations in P14 were not lethal in leaf infections but smaller local lesions and lesser amounts of viral RNA were produced. RNA 2-related subgenomic RNA species of 2.6, 1.4, and 0.7 kb were detected; they presumably direct synthesis of P42, P13, and P14. No species of the length predicted for a P15-specific subgenomic RNA was detected.