VII Eucarpia Meeting on Cucurbit Genetics and Breeding, 2000
ABSTRACT Most plant viruses encode a protein(s) essential for movement from the site of replicati... more ABSTRACT Most plant viruses encode a protein(s) essential for movement from the site of replication to surrounding, uninfected cells. These movement proteins (MPs) can interact with plasmodesmata CPD) to elicit an increase in the molecular size exclusion limit (SEL) from 1.0 kDa to values ranging from 10 to 30 kDa. In recent years, we have established that transgenic tobacco and potato plants expressing the MP of tobacco mosaic virus (TMV) have PD whose SELs are upregulated to more than 9.4 kDa. Interestingly, constitutive expression of the TMV-MP gene in these transgenic plants significantly affects carbon metabolism in source leaves and alters biomass distribution among the various plant organs, indicating that functional motifs on the MP alter carbohydrate translocation. In the present study, melon plants were transformed with the 3a gene product of cucumber mosaic virus (CMV). Expression of the 30-kDa protein in the transgenic plants was verified by western blot analysis. Dye-coupling technique was employed to examine the effect of this protein on plasmodesmal functioning. These studies established that the 30-kDa protein significantly increases the SEL of PD interconnecting the mesophyll cells of melon plants.
Expression of the Aspergillus nigerbeta-glucosidase gene, BGL1, in Nicotiana tabacum plants (cv. ... more Expression of the Aspergillus nigerbeta-glucosidase gene, BGL1, in Nicotiana tabacum plants (cv. Xanthi) had a profound effect on the volatile emissions of intact and crushed leaves. BGL1 was expressed under the control of the cauliflower mosaic virus (CaMV) 35S promoter and targeted to the cytoplasm, cell wall, lytic vacuole (LV), chloroplast or endoplasmic reticulum (ER). Subcellular localization was confirmed by gold immunolabelling, followed by transmission electron microscopy (TEM). Significant beta-glucosidase activity was observed in transgenic plants expressing BGL1 in the cell wall, LV and ER. Compared with controls, all intact transgenic leaves were found to emit increased levels of 2-ethylhexanol, as determined by gas chromatography-mass spectrometry (GC-MS) analysis of the headspace volatiles. Plants expressing BGL1 in the cell wall (Tcw) emitted more trans-caryophyllene than did non-transgenic controls, whereas plants expressing BGL1 in the ER (Ter) and LV (Tvc) emitted more cembrene than did non-transgenic controls. Volatiles released from crushed transgenic leaves and collected with solid-phase microextraction (SPME) polydimethylsiloxane fibre were distinctly enhanced. Significant increases in linalool, nerol, furanoid cis-linalool oxide, 4-methyl-1-pentanol, 6-methyl-hept-5-en-2-ol and 2-ethylhexanol were detected in transgenic plants when compared with wild-type controls. 3-Hydroxyl-beta-ionone levels were increased in crushed Tcw and Ter leaves, but were undetectable in Tvc leaves. The addition of glucoimidazole, a beta-glucosidase inhibitor, abolished the increased emission of these volatiles. These results indicate that the expression of a fungal beta-glucosidase gene in different subcellular compartments has the potential to affect the emission of plant volatiles, and thereby to modify plant-environment communication and aroma of agricultural products.
... CSIRO 2000 Interaction between phloem proteins and viral movement proteins Dror Shalitin and ... more ... CSIRO 2000 Interaction between phloem proteins and viral movement proteins Dror Shalitin and Shmuel Wolf A ... 1997). Localization of CMV-MP to the parietal layer of mature sieve elements of infected Nicotiana clevlandii (Blackman et al. ...
Arsenic trioxide (ATO) induces apoptosis of malignant plasma cells through multiple mechanisms, i... more Arsenic trioxide (ATO) induces apoptosis of malignant plasma cells through multiple mechanisms, including inhibition of DNA binding by nuclear factor kappa-B, a key player in the development of chemoresistance in multiple myeloma (MM). This activity suggests that ATO may be synergistic when combined with other active antimyeloma drugs. To evaluate this, we examined the antimyeloma effects of ATO alone and in combination with bortezomib, melphalan and ascorbic acid (AA) both in vitro and in vivo using a severe combined immunodeficient (SCID)-hu murine myeloma model. Marked synergistic antimyeloma effects were demonstrated when human MM Los Angeles xenograft IgG lambda light chain (LAGlambda-1) cells were treated in vitro with ATO and any one of these agents. SCID mice bearing human MM LAGlambda-1 tumours were treated with single-agent ATO, bortezomib, melphalan, or AA, or combinations of ATO with either bortezomib or melphalan and AA. Animals treated with any of these drugs alone showed tumour growth and increases in paraprotein levels similar to control mice, whereas animals treated with ATO-containing combinations showed markedly suppressed tumour growth and significantly reduced serum paraprotein levels. These in vitro and in vivo results suggest that addition of ATO to other antimyeloma agents may result in improved outcomes for patients with relapsed or refractory MM.
ABSTRACT Seven monoclonal antibodies (MAbs) showing homologous reactions with the VT strain of ci... more ABSTRACT Seven monoclonal antibodies (MAbs) showing homologous reactions with the VT strain of citrus tristeza virus (CTV) were tested against 21 CTV strains or isolates, representing the range of biological diversity and the geographical distribution of CTV in Israel. All the CTV strains gave positive reactions in ELISA with polyclonal antibodies and with one MAb (#25#2). Two MAbs; #13#21 and #3/7 reacted with 19 and 12 out of the 21 CTV strains, respectively. Seventeen CTV strains, including all those previously assigned by sequencing their coat protein gene (CPG) to the CPG-VT group (Mawassi, Gafny & Bar-Joseph, 1993), reacted with five or more MAbs. Four CTV strains of minor epidemiological importance, including two members of the CPG-MT group, did not react with five or more of the MAbs. These results indicated the existence of two serogroups of Israeli CTV strains that can be differentiated by MAbs and which closely correlate with and extend the previous CPG grouping. The extensive biological variation within each CPG group confirms recent analyses suggesting that the CTV pathogenic traits are not necessarily associated with a sequence or antigenic variation of the CTV-CPG.
VII Eucarpia Meeting on Cucurbit Genetics and Breeding, 2000
ABSTRACT Most plant viruses encode a protein(s) essential for movement from the site of replicati... more ABSTRACT Most plant viruses encode a protein(s) essential for movement from the site of replication to surrounding, uninfected cells. These movement proteins (MPs) can interact with plasmodesmata CPD) to elicit an increase in the molecular size exclusion limit (SEL) from 1.0 kDa to values ranging from 10 to 30 kDa. In recent years, we have established that transgenic tobacco and potato plants expressing the MP of tobacco mosaic virus (TMV) have PD whose SELs are upregulated to more than 9.4 kDa. Interestingly, constitutive expression of the TMV-MP gene in these transgenic plants significantly affects carbon metabolism in source leaves and alters biomass distribution among the various plant organs, indicating that functional motifs on the MP alter carbohydrate translocation. In the present study, melon plants were transformed with the 3a gene product of cucumber mosaic virus (CMV). Expression of the 30-kDa protein in the transgenic plants was verified by western blot analysis. Dye-coupling technique was employed to examine the effect of this protein on plasmodesmal functioning. These studies established that the 30-kDa protein significantly increases the SEL of PD interconnecting the mesophyll cells of melon plants.
Expression of the Aspergillus nigerbeta-glucosidase gene, BGL1, in Nicotiana tabacum plants (cv. ... more Expression of the Aspergillus nigerbeta-glucosidase gene, BGL1, in Nicotiana tabacum plants (cv. Xanthi) had a profound effect on the volatile emissions of intact and crushed leaves. BGL1 was expressed under the control of the cauliflower mosaic virus (CaMV) 35S promoter and targeted to the cytoplasm, cell wall, lytic vacuole (LV), chloroplast or endoplasmic reticulum (ER). Subcellular localization was confirmed by gold immunolabelling, followed by transmission electron microscopy (TEM). Significant beta-glucosidase activity was observed in transgenic plants expressing BGL1 in the cell wall, LV and ER. Compared with controls, all intact transgenic leaves were found to emit increased levels of 2-ethylhexanol, as determined by gas chromatography-mass spectrometry (GC-MS) analysis of the headspace volatiles. Plants expressing BGL1 in the cell wall (Tcw) emitted more trans-caryophyllene than did non-transgenic controls, whereas plants expressing BGL1 in the ER (Ter) and LV (Tvc) emitted more cembrene than did non-transgenic controls. Volatiles released from crushed transgenic leaves and collected with solid-phase microextraction (SPME) polydimethylsiloxane fibre were distinctly enhanced. Significant increases in linalool, nerol, furanoid cis-linalool oxide, 4-methyl-1-pentanol, 6-methyl-hept-5-en-2-ol and 2-ethylhexanol were detected in transgenic plants when compared with wild-type controls. 3-Hydroxyl-beta-ionone levels were increased in crushed Tcw and Ter leaves, but were undetectable in Tvc leaves. The addition of glucoimidazole, a beta-glucosidase inhibitor, abolished the increased emission of these volatiles. These results indicate that the expression of a fungal beta-glucosidase gene in different subcellular compartments has the potential to affect the emission of plant volatiles, and thereby to modify plant-environment communication and aroma of agricultural products.
... CSIRO 2000 Interaction between phloem proteins and viral movement proteins Dror Shalitin and ... more ... CSIRO 2000 Interaction between phloem proteins and viral movement proteins Dror Shalitin and Shmuel Wolf A ... 1997). Localization of CMV-MP to the parietal layer of mature sieve elements of infected Nicotiana clevlandii (Blackman et al. ...
Arsenic trioxide (ATO) induces apoptosis of malignant plasma cells through multiple mechanisms, i... more Arsenic trioxide (ATO) induces apoptosis of malignant plasma cells through multiple mechanisms, including inhibition of DNA binding by nuclear factor kappa-B, a key player in the development of chemoresistance in multiple myeloma (MM). This activity suggests that ATO may be synergistic when combined with other active antimyeloma drugs. To evaluate this, we examined the antimyeloma effects of ATO alone and in combination with bortezomib, melphalan and ascorbic acid (AA) both in vitro and in vivo using a severe combined immunodeficient (SCID)-hu murine myeloma model. Marked synergistic antimyeloma effects were demonstrated when human MM Los Angeles xenograft IgG lambda light chain (LAGlambda-1) cells were treated in vitro with ATO and any one of these agents. SCID mice bearing human MM LAGlambda-1 tumours were treated with single-agent ATO, bortezomib, melphalan, or AA, or combinations of ATO with either bortezomib or melphalan and AA. Animals treated with any of these drugs alone showed tumour growth and increases in paraprotein levels similar to control mice, whereas animals treated with ATO-containing combinations showed markedly suppressed tumour growth and significantly reduced serum paraprotein levels. These in vitro and in vivo results suggest that addition of ATO to other antimyeloma agents may result in improved outcomes for patients with relapsed or refractory MM.
ABSTRACT Seven monoclonal antibodies (MAbs) showing homologous reactions with the VT strain of ci... more ABSTRACT Seven monoclonal antibodies (MAbs) showing homologous reactions with the VT strain of citrus tristeza virus (CTV) were tested against 21 CTV strains or isolates, representing the range of biological diversity and the geographical distribution of CTV in Israel. All the CTV strains gave positive reactions in ELISA with polyclonal antibodies and with one MAb (#25#2). Two MAbs; #13#21 and #3/7 reacted with 19 and 12 out of the 21 CTV strains, respectively. Seventeen CTV strains, including all those previously assigned by sequencing their coat protein gene (CPG) to the CPG-VT group (Mawassi, Gafny & Bar-Joseph, 1993), reacted with five or more MAbs. Four CTV strains of minor epidemiological importance, including two members of the CPG-MT group, did not react with five or more of the MAbs. These results indicated the existence of two serogroups of Israeli CTV strains that can be differentiated by MAbs and which closely correlate with and extend the previous CPG grouping. The extensive biological variation within each CPG group confirms recent analyses suggesting that the CTV pathogenic traits are not necessarily associated with a sequence or antigenic variation of the CTV-CPG.
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