| mass determination of native smooth muscle myosin filaments by scanning transmission electron microscopy. | the thick filaments of vertebrate smooth muscle have a fundamentally different arrangement of myosin molecules from the bipolar, helical organization present in striated muscle filaments. this side-polar, non-helical structure is probably critical to the ability of smooth muscles to shorten by large amounts; however, details of myosin organization beyond this general description are unknown. the non-helical arrangement of myosin precludes the use of helical reconstruction methods for structural ... | 2002 | 12054797 |
| kinetics of thermal aggregation of tobacco mosaic virus coat protein. | the kinetics of thermal aggregation of coat protein (cp) of tobacco mosaic virus (tmv) have been studied at 42 and 52 degrees c in a wide range of protein concentrations, [p]0. the kinetics of aggregation were followed by monitoring the increase in the apparent absorbance (a) at 320 nm. at 52 degrees c the kinetic curves may be approximated by the exponential law in the range of tmv cp concentrations from 0.02 to 0.30 mg/ml, the first order rate constant being linearly proportional to [p]0 (50 m ... | 2002 | 12059771 |
| scopoletin expression in elicitor-treated and tobacco mosaic virus-infected tobacco plants. | localized acquired resistance (lar) characterizes a narrow zone of living cells expressing strong defense responses and surrounding cells undergoing a hypersensitive response (hr). in samsun nn tobacco plants, tissues undergoing tobacco mosaic virus-induced or elicitor-induced lar exhibit a strong blue fluorescence under uv light. we have shown that scopoletin and its glucoside, scopolin, accounted for the fluorescence: (1) both compounds were identified after extraction and purification by thin ... | 2002 | 12060240 |
| inability of agrobacterium tumefaciens ribosomes to translate in vivo mrnas containing non-shine-dalgarno translational initiators. | numerous data accumulated during the last decade have shown that the shine-dalgarno (sd) sequence is not a unique initiator of translation for escherichia coli. several other sequences, mostly of viral origin, have demonstrated their capability of either enhancing or initiating translation in vivo. a phage t7 gene 10 sequence, called "epsilon" (epsilon), has shown its high enhancing activity on translation in both escherichia coli and agrobacterium tumefaciens cells. in this study the epsilon, t ... | 2002 | 12064732 |
| a complex fruit-specific type-2 ribosome-inactivating protein from elderberry (sambucus nigra) is correctly processed and assembled in transgenic tobacco plants. | fruits of elderberry (sambucus nigra) express small quantities of a type-2 ribosome-inactivating protein with an exclusive specificity towards the neuac(alpha2,6)gal/galnac disaccharide and a unique molecular structure typified by the occurrence of a disulfide bridge between the b-chains of two adjacent protomers. a cdna clone encoding this so-called sambucus nigra fruit specific agglutinin i (sna-if) was isolated and expressed in tobacco (samsun nn) under the control of the 35s cauliflower mosa ... | 2002 | 12071953 |
| rapid construction of full-length cdna clones of tobacco mosaic virus and the infectivity assay of its in vitro transcript. | the full-length cdna of tobacco mosaic virus faba bean isolate (tmv-b) was amplified with rt-pcr in which t7 promoter sequence was added in the 5' terminus of its upstream primer, so that full-length cdna was put directly under the control of a t7 promoter. the cdna was cloned into plasmid pt7blue and linear dna was got by digesting the recombinant with kpni or kpni and psti. using these linear dna and full-length pcr product as templates, respectively, their in vitro transcripts were inoculated ... | 2000 | 12075453 |
| functional analysis of a dna-shuffled movement protein reveals that microtubules are dispensable for the cell-to-cell movement of tobacco mosaic virus. | microtubules interact strongly with the viral movement protein (mp) of tobacco mosaic virus (tmv) and are thought to transport the viral genome between plant cells. we describe a functionally enhanced dna-shuffled movement protein (mp(r3)) that remained bound to the vertices of the cortical endoplasmic reticulum, showing limited affinity for microtubules. a single amino acid change was shown to confer the mp(r3) phenotype. disruption of the microtubule cytoskeleton in situ with pharmacological a ... | 2002 | 12084822 |
| subcellular localisation, protein interactions, and rna binding of potato mop-top virus triple gene block proteins. | subcellular localisation, protein interactions, and rna binding of the triple gene block proteins (tgbp) of potato mop-top virus (pmtv) were studied. the 13-kda (tgbp2) and 21-kda (tgbp3) proteins with or without green fluorescent protein fused to their n-terminus, and the 51-kda protein (tgbp1) were expressed individually from a recombinant tobacco mosaic virus (tmv) vector. fluorescent images and western immunoblotting experiments of recombinant tmv-infected nicotiana benthamiana cells suggest ... | 2002 | 12093178 |
| inhibition of tobacco mosaic virus replication in lateral roots is dependent on an activated meristem-derived signal. | viral invasion of the root system of nicotiana benthamiana was studied noninvasively with a tobacco mosaic virus (tmv) vector expressing the green-fluorescent protein (gfp). lateral root primordia, which developed from the pericycle of primary roots, became heavily infected as they emerged from the root cortex. however, following emergence, a progressive wave of viral inhibition occurred that originated in the lateral-root meristem and progressed towards its base. excision of source and sink tis ... | 2002 | 12099219 |
| production of immunogenic vp6 protein of bovine group a rotavirus in transgenic potato plants. | we report here the production of transgenic potato plants expressing the major capsid protein vp6 of bovine group a rotavirus (gar). transgenic plants under the control of a cauliflower mosaic virus 35s promoter, or a modified promoter linked to the tobacco mosaic virus 5'-untranslated sequence were positive for gar antigens by elisa. the expressed protein was consistent in size with vp6 of gar by western blot assay. the presence of the vp6 gene and its transcript was detected by pcr and rt-pcr. ... | 2002 | 12111435 |
| effect of yeast cta1 gene expression on response of tobacco plants to tobacco mosaic virus infection. | the response of tobacco (nicotiana tabacum l. cv xanthi-nc) plants with elevated catalase activity was studied after infection by tobacco mosaic virus (tmv). these plants contain the yeast (saccharomyces cerevisiae) peroxisomal catalase gene cta1 under the control of the cauliflower mosaic virus 35s promoter. the transgenic lines exhibited 2- to 4-fold higher total in vitro catalase activity than untransformed control plants under normal growth conditions. cellular localization of the cta1 prote ... | 2002 | 12114558 |
| potato gene y-1 is an n gene homolog that confers cell death upon infection with potato virus y. | adg2 is a dna sequence mapped to a resistance (r) gene-rich region at the distal end of chromosome xi in potato (solanum tuberosum subsp. andigena). the gene, in which adg2 represents the predicted nucleotide-binding domain (nbs), was cloned and characterized. the coding region of the gene (designated as y-1) is 6,187 bp long and structurally similar to gene n that confers hypersensitive resistance to tobacco mosaic virus in nicotiana spp. both belong to the tir-nbs-lrr class of genes and show 5 ... | 2002 | 12118888 |
| role of scf ubiquitin-ligase and the cop9 signalosome in the n gene-mediated resistance response to tobacco mosaic virus. | the tobacco n gene confers resistance to tobacco mosaic virus (tmv) and encodes a toll-interleukin-1 receptor/nucleotide binding/leu-rich repeat class protein. recent evidence indicates that the nicotiana benthamiana rar1 gene (nbrar1), which encodes a protein with a zinc finger motif called chord (cys- and his-rich domain), is required for the function of n. to investigate the role of nbrar1 in plant defense, we identified its interaction partners. we show that the nbrar1 protein interacts with ... | 2002 | 12119369 |
| effects of replacing the movement protein gene of tobacco mosaic virus by that of tomato mosaic virus. | the broad bean strain of tobacco mosaic virus (tmv-b) infects nicotiana tabacum white burley systemically whereas the tomato strain of t. mosaic virus (tomv-s1) induces necrotic local lesions and is restricted to inoculated leaves. to examine the possible role of the viral movement protein (mp) in these symptom differences, a chimaeric virus (t/omp) was produced in which the tmv-b mp gene was replaced by the tomv-s1 mp gene. t/omp induced the same symptoms as tmv-b in n. tabacum white burley. ho ... | 2002 | 12135790 |
| the 5'-leader of tobacco mosaic virus promotes translation through enhanced recruitment of eif4f. | the 5'-leader sequence (called omega) of tobacco mosaic virus (tmv) functions as a translational enhancer in plants. a poly(caa) region within omega is responsible for the translation enhancement and serves as a binding site for the heat shock protein, hsp101, which is required for the translational enhancement. genetic analysis of the hsp101-mediated enhancement of translation from omega-containing mrna suggested that two eukaryotic initiation factors (eifs), i.e. eif4g and eif3, were necessary ... | 2002 | 12140325 |
| epigenetic modification of plants with systemic rna viruses. | knowledge of gene function is critical to the development of new plant traits for improved agricultural and industrial applications. viral expression vectors offer a rapid and proven method to provide epigenetic expression of foreign sequences throughout infected plants. expression of these sequences from viral vectors can lead to gain- or loss-of-function phenotypes, allowing gene function to be determined by phenotypic or biochemical effects in the infected plant. tobacco mosaic virus and barl ... | 2002 | 12143960 |
| tobacco mosaic virus assembly and disassembly: determinants in pathogenicity and resistance. | the structural proteins of plant viruses have evolved to self-associate into complex macromolecules that are centrally involved in virus biology. in this review, the structural and biophysical properties of the tobacco mosaic virus (tmv) coat protein (cp) are addressed in relation to its role in host resistance and disease development. tmv cp affects the display of several specific virus and host responses, including cross-protection, systemic virus movement, hypersensitive disease resistance, a ... | 2002 | 12147762 |
| expression in plants and immunogenicity of plant virus-based experimental rabies vaccine. | a new approach to the production and delivery of vaccine antigens is the use of engineered amino virus-based vectors. a chimeric peptide containing antigenic determinants from rabies virus glycoprotein (g protein) (amino acids 253-275) and nucleoprotein (n protein) (amino acids 404-418) was pcr-amplified and cloned as a translational fusion product with the alfalfa mosaic virus (almv) coat protein (cp). this recombinant cp was expressed in two plant virus-based expression systems. the first one ... | 2002 | 12163267 |
| suppression of a key gene involved in chlorophyll biosynthesis by means of virus-inducing gene silencing. | the chlh gene coding the h subunit of magnesium chelatase, an enzyme involved in chlorophyll biosynthesis, was silenced in nicotiana benthamiana plants by infection with tobacco mosaic virus vectors (ptmv-30b) containing 67,214 or 549 nt long chlh inserts. silencing of the nuclear chlh gene induced a chimeric phenotype with green and yellow/white leaves associated with alterations of chloroplast shape and ultrastructure. the symptoms became first evident around veins of young leaves, and only la ... | 2002 | 12175014 |
| mitochondrial alternative oxidase is not a critical component of plant viral resistance but may play a role in the hypersensitive response. | transgenic tobacco (nicotiana tabacum) with altered levels of mitochondrial alternative oxidase (aox) were used to examine the potential role of this electron transport chain protein in resistance to tobacco mosaic virus. we examined the effect of aox expression on the salicylic acid-induced resistance in susceptible plants and the resistance responses of plants harboring the n-gene. a lack of aox did not compromise the ability of salicylic acid treatment to heighten the resistance of susceptibl ... | 2002 | 12177499 |
| influence of substrate and ribozyme sequences on the functions of ribozyme. | the mono-component ribozyme rz1, rz3 and rz4 were ligated in different orders into two tri-component ribozymes rz134 and rz413.both tri-component ribozymes could cleave individual specific substrate sequences from different regions of the tobacco mosaic virus (tmv) rna. the cleavage efficiency and specificity of each unit-ribozymes in the tri-component ribozymes to its substrate was similar to its mono-ribozyme counterpart. when the three substrates were mixed and used as substrates for the tri- ... | 1997 | 12219238 |
| influence of environmental stress on biomass partitioning in transgenic tobacco plants expressing the movement protein of tobacco mosaic virus. | the influence of various environmental factors on biomass partitioning between shoots and roots in transgenic tobacco (nicotiana tabacum) plants expressing the movement protein (mp) of tobacco mosaic virus (tmv) was investigated. tmv-mp-expressing transgenic plants exhibited a root-to-shoot ratio that was approximately 40% below that of transgenic vector control plants. when transgenic plants expressing the tmv-mp were subjected to water-stress conditions, the root-to-shoot ratio was increased t ... | 1997 | 12223721 |
| expression of pokeweed antiviral protein in transgenic plants induces virus resistance in grafted wild-type plants independently of salicylic acid accumulation and pathogenesis-related protein synthesis. | pokeweed antiviral protein (pap), a 29-kd protein isolated from phytolacca americana, inhibits translation by catalytically removing a specific adenine residue from the large rrna of the 60s subunit of eukaryotic ribosomes. transgenic tobacco (nicotiana tabacum) plants expressing pap or a variant (pap-v) were shown to be resistant to a broad spectrum of plant viruses. expression of pap-v in transgenic plants induces synthesis of pathogenesis-related proteins and a very weak (<2-fold) increase in ... | 1997 | 12223762 |
| local and systemic responses of antioxidants to tobacco mosaic virus infection and to salicylic acid in tobacco (role in systemic acquired resistance). | changes in ascorbate and glutathione levels and in activities of ascorbate peroxidase, catalase, dehydroascorbate reductase (dhar), glutathione reductase (gr), glutathione s-transferase (gst), and superoxide dismutase (sod) were investigated in tobacco mosaic virus (tmv)-inoculated lower leaves and in non-inoculated upper leaves of nicotiana tabacum l. cv xanthi-nc. in separate experiments the effects of exogenous salicylic acid (sa) were also studied. symptom appearance after tmv inoculation wa ... | 1997 | 12223782 |
| the effects of salicylic acid and tobacco mosaic virus infection on the alternative oxidase of tobacco. | salicylic acid (sa) is a signal in systemic acquired resistance and an inducer of the alternative oxidase protein in tobacco (nicotiana tabacum cv xanthi nc) cell suspensions and during thermogenesis in aroid spadices. the effects of sa on the levels of alternative oxidase protein and the pathogenesis-related 1a mrna (a marker for systemic acquired resistance), and on the partitioning of electrons between the cyt and alternative pathways were investigated in tobacco. leaves were treated with 1.0 ... | 1997 | 12223844 |
| phloem-specific expression of the tobacco mosaic virus movement protein alters carbon metabolism and partitioning in transgenic potato plants. | the tobacco mosaic virus movement protein (tmv-mp) has pleiotropic effects when expressed in transgenic tobacco (nicotiana tabacum) plants. in addition to its ability to increase the plasmodesmal size-exclusion limit, the tmv-mp alters carbohydrate metabolism in source leaves and dry matter partitioning between the various plant organs. in the present study the tmv-mp was expressed under the control of a phloem-specific promoter (rolc), and this system was employed to further explore the potenti ... | 1997 | 12223883 |
| tissue-specific expression of the tobacco mosaic virus movement protein in transgenic potato plants alters plasmodesmal function and carbohydrate partitioning. | transgenic potato (solanum tuberosum) plants expressing the movement protein (mp) of tobacco mosaic virus (tmv) under the control of the promoters from the class i patatin gene (b33) or the nuclear photosynthesis gene (st-ls1) were employed to further explore the mode by which this viral protein interacts with cellular metabolism to change carbohydrate allocation. dye-coupling experiments established that expression of the tmv-mp alters plasmodesmal function in both potato leaves and tubers when ... | 1996 | 12226308 |
| a strobilurin fungicide enhances the resistance of tobacco against tobacco mosaic virus and pseudomonas syringae pv tabaci. | the strobilurin class of fungicides comprises a variety of synthetic plant-protecting compounds with broad-spectrum antifungal activity. in the present study, we demonstrate that a strobilurin fungicide, f 500 (pyraclostrobin), enhances the resistance of tobacco (nicotiana tabacum cv xanthi nc) against infection by either tobacco mosaic virus (tmv) or the wildfire pathogen pseudomonas syringae pv tabaci. f 500 was also active at enhancing tmv resistance in nahg transgenic tobacco plants unable t ... | 2002 | 12226492 |
| induction of udp-glucose:salicylic acid glucosyltransferase activity in tobacco mosaic virus-inoculated tobacco (nicotiana tabacum) leaves. | salicylic acid (sa) is a putative signal that activates plant resistance to pathogens. sa levels increase systemically following the hypersensitive response produced by tobacco mosaic virus (tmv) inoculation of tobacco (nicotiana tabacum l. cv xanthi-nc) leaves. the sa increase in the inoculated leaf coincided with the appearance of a [beta]-glucosidase-hydrolyzable sa conjugate identified as [beta]-o-d-glucosylsalicylic acid (gsa). sa and gsa accumulation in the tmv-inoculated leaf paralleled t ... | 1993 | 12231791 |
| pathway of salicylic acid biosynthesis in healthy and virus-inoculated tobacco. | salicylic acid (sa) is a likely endogenous regulator of localized and systemic disease resistance in plants. during the hypersensitive response of nicotiana tabacum l. cv xanthi-nc to tobacco mosaic virus (tmv), sa levels rise dramatically. we studied sa biosynthesis in healthy and tmv-inoculated tobacco by monitoring the levels of sa and its likely precursors in extracts of leaves and cell suspensions. in tmv-inoculated leaves, stimulation of sa accumulation is accompanied by a corresponding in ... | 1993 | 12231938 |
| induction of benzoic acid 2-hydroxylase in virus-inoculated tobacco. | salicylic acid (sa) plays an important role in the induction of plant resistance to pathogens. an accompanying article (n. yalpani, j. leon, m.a. lawton, i. raskin [1993] plant physiol 103: 315-321) shows that sa is synthesized via the decarboxylation of cinnamic acid to benzoic acid (ba), which is, in turn, hydroxylated to sa. leaf extracts of tobacco (nicotiana tabacum l. cv xanthi-nc) catalyze the 2-hydroxylation of ba to sa. the monooxygenase catalyzing this reaction, benzoic acid 2-hydroxyl ... | 1993 | 12231939 |
| effects of two strains of tobacco mosaic virus on photosynthetic characteristics and nitrogen partitioning in leaves of nicotiana tabacum cv xanthi during photoacclimation under two nitrogen nutrition regimes. | photoacclimation was studied in tobacco leaves (nicotiana tabacum cv xanthi) infected with two strains of tobacco mosaic virus (tmv) and grown under different light and nitrogen nutrition regimes. photosynthetic acclimation measured by the quantum yield and the maximum rate in saturating light of co2-saturated photosynthesis was impaired to a greater extent in tobacco leaves infected with tmv strain pv230 than in those infected with tmv strain pv42. infection with tmv strain pv230 severely impai ... | 1994 | 12232147 |
| susceptibility of tobacco leaves to photoinhibition following infection with two strains of tobacco mosaic virus under different light and nitrogen nutrition regimes. | sensitivity to photoinhibition under high light stress (2000 [mu]mol photons m-2 s-1 for 2 h in air) and recovery from this stress were examined in leaves of control, uninfected tobacco (nicotiana tabacum cv xanthi) leaves and in leaves in tobacco plants infected with tobacco mosaic virus (tmv) when grown under low light (150-200 [mu]mol photons m-2 s-1) or high light (1200 [mu]mol photons m-2 s-1) with high (8.0 mm) or low (0.5 mm) nitrate supply. photoinhibition was monitored using the dark-ad ... | 1994 | 12232148 |
| diagnosis of the earliest strain-specific interactions between tobacco mosaic virus and chloroplasts of tobacco leaves in vivo by means of chlorophyll fluorescence imaging. | fluorescence imaging was used to diagnose early stages of the strain-specific interactions between tobacco mosaic virus (strain pv230) and chloroplasts following infection of tobacco leaves (nicotiana tabacum cv xanthi). the earliest indication of interaction in tissues that ultimately become chlorotic was a reduction in chlorophyll fluorescence, and there was little fluorescence quenching compared with adjacent healthy tissues. subsequently, fluorescence increased but remained unquenched. in th ... | 1994 | 12232149 |
| the construction and complementary expression of two tmv defective particles in tobacco. | two defective mutants of the tobacco mosaic virus (tmv), tmvrp and tmvcp were constructed and assembled in vitro. in tmvrp, the 3'-end and part of the tmv coat protein (cp) gene was deleted; in tmrcp, most of the replicase genes were deleted. these mutant particles were separately or complementally inoculated into the tobacco protoplasts by electroporation. the synthesis of tmv coat protein was deteted by immuno dot-blot technique at 2 h after inoculation only in those complementally infected pr ... | 1996 | 12232627 |
| salicylic acid interferes with tobacco mosaic virus replication via a novel salicylhydroxamic acid-sensitive mechanism. | salicylic acid (sa) induces resistance to all plant pathogens, including bacteria, fungi, and viruses, but the mechanism by which sa engenders resistance to viruses is not known. pretreatment of tobacco mosaic virus (tmv)-susceptible (nn genotype) tobacco tissue with sa reduced the levels of viral rnas and viral coat protein accumulating after inoculation with tmv. viral rnas were not affected equally, suggesting that sa treatment interferes with tmv replication. salicylhydroxamic acid (sham), a ... | 1997 | 12237364 |
| molecular structures of viruses from raman optical activity. | a vibrational raman optical activity (roa) study of a range of different structural types of virus exemplified by filamentous bacteriophage fd, tobacco mosaic virus, satellite tobacco mosaic virus, bacteriophage ms2 and cowpea mosaic virus has revealed that, on account of its sensitivity to chirality, roa is an incisive probe of their aqueous solution structures at the molecular level. protein roa bands are especially prominent from which, as we have shown by comparison with the roa spectra of p ... | 2002 | 12237443 |
| inhibition of programmed cell death in tobacco plants during a pathogen-induced hypersensitive response at low oxygen pressure. | the hypersensitive response (hr) of plants to invading pathogens is thought to involve a coordinated activation of plant defense mechanisms and programmed cell death (pcd). to date, little is known about the mechanism underlying death of plant cells during this response. in addition, it is not known whether suppression of pcd affects the induction of other defense mechanisms during the hr. here, we report that death of tobacco cells (genotype nn) infected with tobacco mosaic virus (tmv) is inhib ... | 1996 | 12239372 |
| decreased susceptibility to viral disease of [beta]-1,3-glucanase-deficient plants generated by antisense transformation. | antifungal class i [beta]-1,3-glucanases are believed to be part of the constitutive and induced defenses of plants against fungal infection. unexpectedly, mutants deficient in these enzymes generated by antisense transformation showed markedly reduced lesion size, lesion number, and virus yield in the local-lesion response of havana 425 tobacco to tobacco mosaic virus (tmv) and of nicotiana sylvestris to tobacco necrosis virus. these mutants also showed decreased severity of mosaic disease symp ... | 1996 | 12239410 |
| is salicylic acid a translocated signal of systemic acquired resistance in tobacco? | salicylic acid (sa) is a likely endogenous signal in the development of systemic acquired resistance (sar) in some dicotyledonous plants. in tobacco mosaic virus (tmv)-resistant xanthi-nc tobacco, sa levels increase systemically following the inoculation of a single leaf with tmv. to determine the extent to which systemic increases in sa result from sa export from the inoculated leaf, sa produced in tmv-inoculated or healthy leaves was noninvasively labeled with 18o2. spatial and temporal distri ... | 1995 | 12242358 |
| a hot pepper cdna encoding ascorbate peroxidase is induced during the incompatible interaction with virus and bacteria. | capsicum annuum l. is infected by a number of viruses, including the tobacco mosaic virus (tmv). to study the defense-related genes that are induced by tmv in hot peppers, the pepper plant, which is susceptible to p1.2 but resistant to the p0 pathotype of tmv, was inoculated with tmv-p0. differential screening isolated the genes that were specifically up- or down-regulated during the hypersensitive response (hr). the caapx1 cdna clone that putatively encodes a polypeptide of cytosolic ascorbate ... | 2002 | 12243356 |
| plant defense genes are synergistically induced by ethylene and methyl jasmonate. | combinations of ethylene and methyl jasmonate (e/meja) synergistically induced members of both groups 1 and 5 of the pathogenesis-related (pr) superfamily of defense genes. e/meja caused a synergistic induction of pr-1b and osmotin (pr-5) mrna accumulation in tobacco seedlings. e/meja also synergistically activated the osmotin promoter fused to a [beta]-glucuronidase marker gene in a tissue-specific manner. the e/meja responsiveness of the osmotin promoter was localized on a -248 to +45 fragment ... | 1994 | 12244267 |
| temperature-dependent induction of salicylic acid and its conjugates during the resistance response to tobacco mosaic virus infection. | increases in endogenous salicylic acid (sa) levels and induction of several families of pathogenesis-related genes (pr-1 through pr-5) occur during the resistance response of tobacco to tobacco mosaic virus infection. we found that at temperatures that prevent the induction of pr genes and resistance, the increases in sa levels were eliminated. the addition of exogenous sa to infected plants at these temperatures was sufficient to induce the pr genes but not the hypersensitive response. however, ... | 1992 | 12297650 |
| coordinate gene activity in response to agents that induce systemic acquired resistance. | in a variety of plant species, the development of necrotic lesions in response to pathogen infection leads to induction of generalized disease resistance in uninfected tissues. a well-studied example of this "immunity" reaction is systemic acquired resistance (sar) in tobacco. sar is characterized by the development of a disease-resistant state in plants that have reacted hypersensitively to previous infection by tobacco mosaic virus. here, we show that the onset of sar correlates with the coord ... | 1991 | 12324583 |
| a nuclear localization signal and a membrane association domain contribute to the cellular localization of the tobacco mosaic virus 126-kda replicase protein. | a transient expression system using onion epidermal cells was used to investigate domains of the tobacco mosaic virus (tmv) 126-kda replicase protein involved in cellular localization. initially, a nuclear localization signal (nls), identified within the amino-terminus of the 126-kda protein, was investigated for its functionality using fusion constructs containing the green fluorescent protein (gfp). fusion of the amino-terminal 70 amino acids of the 126-kda protein, containing the nls, to a be ... | 2002 | 12359448 |
| detection and differentiation of serologically cross-reacting tobamoviruses of economical importance by rt-pcr and rt-pcr-rflp. | a procedure involving reverse transcription followed by the polymerase chain reaction (rt-pcr) using a single primer pair was developed for the detection of five tobamovirus species which are related serologically. either with a subsequent restriction enzyme analysis (rt-pcr-rflp) or with a rt-pcr using species specific primers the five species can be differentiated. to differentiate those species by serological means is time consuming and might give ambiguous results. with the example of the is ... | 2002 | 12367724 |
| multitrophic interactions of the silverleaf whitefly, host plants, competing herbivores, and phytopathogens. | our laboratory found that silverleaf whitefly (slw; bemisia argentifolii bellows & perring) feeding alters host plant physiology and chemistry. the slw induces a number of host plant defenses, including pathogenesis-related (pr) protein accumulation (e.g., chitinases, beta-1,3-glucanases, peroxidases, chitosanases, etc.). induction of the pr proteins by slw feeding occurs in various plant species and varieties. the extent and type of induction is dependent on a number of factors that include hos ... | 2002 | 12432517 |
| the origin of modern plant virology. | plant virology, born with mayer's work, saw a first (embryonic) phase of development during two decades (1900-1920) with outstanding contributions from dimitri ivanovski, martinus beijerinck, erwin baur and harry allard. between 1920 and 1930 a second phase saw the elaboration of surprising hypotheses concerning the enigmatic nature of viruses and experimental evidence of great stress was obtained. revolutionary renewal began from the mid-1930s on the basis of a body of knowledge which was organ ... | 2002 | 12437232 |
| potato spindle tuber viroid strains of different pathogenicity induces and suppresses expression of common and unique genes in infected tomato. | viroids are the smallest plant pathogens. these rnas do not encode proteins and are not encapsidated, and yet they can replicate autonomously, move systemically, and cause diseases in infected plants. notably, strains of a viroid with subtle differences in nucleotide sequences can cause dramatically different symptoms in infected plants. these features make viroids unique probes to investigate the role of a pathogenic rna genome in triggering host responses. we conducted a comprehensive analysis ... | 2002 | 12437296 |
| novel n gene-associated, temperature-independent resistance to the movement of tobacco mosaic virus vectors neutralized by a cucumber mosaic virus rna1 transgene. | the n gene conditions for resistance to tobacco mosaic virus (tmv) but only below 28 degrees c. however, a tmv-based vector expressing green fluorescent protein (tmv-gfp) showed only limited movement at 33 degrees c in tobacco plants harboring the n gene and other genes cointrogressed from nicotiana glutinosa. tmv-gfp moved efficiently in tobacco plants that either lacked these genes or that contained the n gene but were transgenic for rna1 of cucumber mosaic virus. these findings identified nov ... | 2002 | 12438616 |
| virus-induced silencing of ftsh gene in nicotiana benthmiana causes a striking bleached leaf phenotype. | a recombinant potato virus x (pvx) vector, ptxs.ftsh, harboring partial sequence of ftsh gene of nicotiana benthamiana was constructed to silence the expression of endogenous ftsh homologous gene in n. benthamiana. inoculation with in vitro runoff transcript of ptxs.ftsh to n. benthamiana plants allowed silencing of ftsh, causing striking bleaching of upper leaves reminiscent of var2 mutant phenotype of arabidopsis thaliana. ftsh-silenced plants exhibited no resistance against tobacco mosaic vir ... | 2002 | 12441644 |
| down-regulation of antioxidative capacity in a transgenic tobacco which fails to develop acquired resistance to necrotization caused by tmv. | antioxidant status was assayed in leaves of two local lesion hosts of tobacco mosaic virus (tmv), namely in wild-type xanthi-nc tobacco and in nahg transgenic tobacco, the latter of which is not able to accumulate salicylic acid (sa) and therefore is unable to develop systemic acquired resistance (sar). activities of several enzymes related to antioxidative defense, and the levels of glutathione, chlorogenic acid and rutin were studied. the majority of antioxidant enzymes were less active in uni ... | 2002 | 12448824 |
| production of anti-virus, viroid plants by genetic manipulations. | many pathogenic plant viruses are rna viruses, which initiate production of double-stranded rna intermediates when they replicate in host plant cells. introduction of double-stranded rna-specific ribonucleases such as the schizosaccharomyces pombe derived pac i protein and animal cell derived interferon-induced 2',5'-oligoadenylate synthetase (2-5 aase)/ribonuclease l (rnase l) system into various plants may make plants resistant to various pathogenic viruses and viroids. we have demonstrated th ... | 2002 | 12449532 |
| comparative analysis of protein kinases that phosphorylate tobacco mosaic virus movement protein in vitro. | | 2002 | 12469511 |
| spatio-temporal expression of patatin-like lipid acyl hydrolases and accumulation of jasmonates in elicitor-treated tobacco leaves are not affected by endogenous levels of salicylic acid. | we have previously isolated three tobacco genes (ntpat) encoding patatin-like proteins, getting rapidly induced during the hypersensitive response (hr) to tobacco mosaic virus, in advance to jasmonate accumulation. ntpat enzymes are lipid acyl hydrolases that display high phospholipase a2 (pla2) activity and may mobilize fatty acid precursors of oxylipins. here, we performed a detailed study of ntpat gene regulation under various biotic and abiotic stresses. pla2 activity was poorly induced in r ... | 2002 | 12472690 |
| sviss - a novel transient gene silencing system for gene function discovery and validation in tobacco plants. | we developed a novel, two-component transient gene silencing system in which the satellite tobacco mosaic virus (stmv) is used as vector for the delivery of inhibitory rna into tobacco plants and the tobacco mosaic virus strain u2 (tmv-u2) is used as helper virus for supplying replication and movement proteins in trans. the main advantage of the system is that by uncoupling virus replication components from silencing induction components, the intensity of silencing becomes more pronounced. we ca ... | 2002 | 12472699 |
| the alpha-helical d1 domain of the tobacco bzip transcription factor bzi-1 interacts with the ankyrin-repeat protein ank1 and is important for bzi-1 function, both in auxin signaling and pathogen response. | the tobacco (nicotiana tabacum) bzip transcription factor bzi-1 is involved in auxin-mediated growth responses and in establishing pathogen defenses. transgenic plants expressing a dominant-negative bzi-1-deltan derivative, which lacks the n-terminal activation domain, showed altered vegetative growth. in particular auxin-induced rooting and formation of tobacco mosaic virus-induced hypersensitive response lesions are affected. bzi-1-related proteins described in various plant species share the ... | 2003 | 12499372 |
| the rate and character of spontaneous mutation in an rna virus. | estimates of spontaneous mutation rates for rna viruses are few and uncertain, most notably due to their dependence on tiny mutation reporter sequences that may not well represent the whole genome. we report here an estimate of the spontaneous mutation rate of tobacco mosaic virus using an 804-base cognate mutational target, the viral mp gene that encodes the movement protein (mp). selection against newly arising mutants was countered by providing mp function from a transgene. the estimated geno ... | 2002 | 12524327 |
| molecular cloning and biological activity of alpha-, beta-, and gamma-megaspermin, three elicitins secreted by phytophthora megasperma h20. | we report on the molecular cloning of the phytophthora megasperma h20 (pmh20) glycoprotein shown previously as an inducer of the hypersensitive response, of localized acquired resistance and of systemic acquired resistance in tobacco (nicotiana tabacum), and of the pmh20 alpha- and beta-megaspermin, two elicitins of class i-a and i-b, respectively. the structure of the glycoprotein shows a signal peptide of 20 amino acids followed by the typical elicitin 98-amino acid-long domain and a 77-amino ... | 2003 | 12529524 |
| biochemical identification of proteasome-associated endonuclease activity in sunflower. | proteasomes have been purified from sunflower hypocotyles. they elute with a molecular mass of 600 kda from gel filtration columns and two-dimensional gel electrophoresis indicates that the complex contains at least 20 different protein subunits. peptide microsequencing revealed the presence of four subunits homologous to subunits beta2, beta6, alpha5 and alpha6 of plant proteasomes. these proteasomes have chymotrypsin-like activity and the highly purified fraction of this complex is associated ... | 2003 | 12535608 |
| [ultrastructural differences of rmv and tmv infected nicotiana tabacum mesophyll cells for distinguishing virus strains]. | nine strains of ribgrass mosaic virus (rmv) and tobacco mosaic virus(tmv) from cruciferous and solanaceous plants in different geographic regions of china were used to inoculate 4-leave-old plants of nicotiana tobacum for observation of ultrastructually pathological changes due to infection of different strains. the samples of the mesophyll cells of the plants 15 d after inoculation were prepared in a routine and examined using transmission electronic microscopy. characteristic virion arrangemen ... | 1998 | 12548920 |
| [effect of decapitation on the systemic acquired resistance of hypersensitive tobacco mosaic virus]. | the decapitation depressed the development of the system acquired resistance to reinfection with tobacco mosaic virus in the leaves of hypersensitive tobacco plants nicotiana tabacum l. (v. xanthi nc) and in protoplasts, isolated from these leaves. | 2002 | 12557491 |
| [production of monoclonal antibodies to tomato mosaic virus and application in virus detection]. | four hybridoma cell lines secreting monoclonal antibodies(mabs) against tomato mosaic virus(tomv) were produced by fusing mouse myeloma cells(sp2/0) with spleen cells from bal b/c immunized by the tomv particle. the four mabs could specifically react with tomv, and the mabs from two cell lines can react with tomv and tmv simultaneously. the titres of ascitic fluids of four mabs ranged from 1:32,000 to 1:1,024,000 with elisa, and the sensitivity for detection virus from the plant sap reached over ... | 2002 | 12557552 |
| a systemic resistance inducing antiviral protein with n-glycosidase activity from bougainvillea xbuttiana leaves. | an antiviral protein from bougainvillea xbuttiana leaves induced systemic resistance in host plants n. glutinosa and cyamopsis tetragonoloba against tmv and srv, respectively which was reversed by actinomycin d, when applied immediately or shortly after antiviral protein treatment. when the inhibitor was applied to the host plant leaves post inoculation, it was effective if applied upto 4 h after virus infection. it also delayed the expression of symptoms in systemic hosts of tmv. the inhibitor ... | 2001 | 12562026 |
| dynamics of the vigs-mediated chimeric silencing of the nicotiana benthamiana chlh gene and of the tobacco mosaic virus vector. | the chlh gene, encoding for the h subunit of the magnesium chelatase enzyme, was silenced in nicotiana bentahamiana plants by virus-induced gene silencing (vigs), using tobacco mosaic virus (tmv) expression vector. strong silencing of the chlh target gene was initiated only in the apical tissues, in which the endogenous transcription level of the target gene and the level of tmv vector rna were both very high. the virus vector was also targeted by vigs, and its suppression was correlated with th ... | 2003 | 12575743 |
| sulfated fucan oligosaccharides elicit defense responses in tobacco and local and systemic resistance against tobacco mosaic virus. | sulfated fucans are common structural components of the cell walls of marine brown algae. using a fucan-degrading hydrolase isolated from a marine bacterium, we prepared sulfated fucan oligosaccharides made of mono- and disulfated fucose units alternatively bound by alpha-1,4 and alpha-1,3 glycosidic linkages, respectively. here, we report on the elicitor activity of such fucan oligosaccharide preparations in tobacco. in suspension cell cultures, oligofucans at the dose of 200 microg ml(-1) rapi ... | 2003 | 12575745 |
| an umbraviral protein, involved in long-distance rna movement, binds viral rna and forms unique, protective ribonucleoprotein complexes. | umbraviruses are different from most other viruses in that they do not encode a conventional capsid protein (cp); therefore, no recognizable virus particles are formed in infected plants. their lack of a cp is compensated for by the orf3 protein, which fulfils functions that are provided by the cps of other viruses, such as protection and long-distance movement of viral rna. when the groundnut rosette virus (grv) orf3 protein was expressed from tobacco mosaic virus (tmv) in place of the tmv cp [ ... | 2003 | 12584328 |
| biological and molecular comparison between localized and systemic acquired resistance induced in tobacco by a phytophthora megasperma glycoprotein elicitin. | we have compared localized (lar) and systemic (sar) acquired resistance induced in tobacco by a hypersensitive response (hr) inducing phytophthora megasperma glycoprotein elicitin. three different zones were taken into account: lar, sar(t) and sar(s). the lar zone was 5-10 mm wide and surrounded the hr lesion. sar(t) was the tissue of the elicitor-treated leaf immediately beyond the lar zone. the systemic leaf was called sar(s). glycoprotein-treated plants showed enhanced resistance to challenge ... | 2003 | 12602895 |
| dysfunctionality of a tobacco mosaic virus movement protein mutant mimicking threonine 104 phosphorylation. | replication of tobacco mosaic virus (tmv) is connected with endoplasmic reticulum (er)-associated membranes at early stages of infection. this study reports that tmv movement protein (mp)-specific protein kinases (pks) associated with the er of tobacco were capable of phosphorylating thr(104) in tmv mp. the mp-specific pks with apparent molecular masses of about 45-50 kda and 38 kda were revealed by gel pk assays. two types of mutations were introduced in tmv mp gene of wild-type tmv u1 genome t ... | 2003 | 12604825 |
| brassinosteroid functions in a broad range of disease resistance in tobacco and rice. | brassinolide (bl), considered to be the most important brassinosteroid (br) and playing pivotal roles in the hormonal regulation of plant growth and development, was found to induce disease resistance in plants. to study the potentialities of bl activity on stress responding systems, we analyzed its ability to induce disease resistance in tobacco and rice plants. wild-type tobacco treated with bl exhibited enhanced resistance to the viral pathogen tobacco mosaic virus (tmv), the bacterial pathog ... | 2003 | 12609030 |
| oligomerization and activity of the helicase domain of the tobacco mosaic virus 126- and 183-kilodalton replicase proteins. | a protein-protein interaction within the helicase domain of the tobacco mosaic virus (tmv) 126- and 183-kda replicase proteins was previously implicated in virus replication (s. goregaoker, d. lewandowski, and j. culver, virology 282:320-328, 2001). to further characterize the interaction, polypeptides covering the interacting portions of the tmv helicase domain were expressed and purified. biochemical characterizations demonstrated that the helicase domain polypeptides hydrolyzed atp and bound ... | 2003 | 12610130 |
| the soybean retroelement sire1 uses stop codon suppression to express its envelope-like protein. | the soybean sire1 family of ty1/copia retrotransposons encodes an envelope-like gene (env-like). we analysed the dna sequences of nine sire1 insertions and observed that the gag/pol and env-like genes are in the same reading frame and separated by a single uag stop codon. the six nucleotides immediately downstream of the stop codon conform to a degenerate nucleotide motif, caryya, which is sufficient to facilitate stop codon suppression in tobacco mosaic virus. in vivo stop codon suppression ass ... | 2003 | 12634845 |
| analysis of the involvement of an inducible arabidopsis rna-dependent rna polymerase in antiviral defense. | rna-dependent rna polymerases (rdrps) have been implicated in posttranscriptional gene silencing (ptgs) and antiviral defense. an arabidopsis rdrp (sde1/sgs2) has been previously shown to be required for transgene-induced ptgs but has no general role in antiviral defense. on the other hand, we have recently shown that transgenic tobacco deficient in an inducible rdrp (ntrdrp1) activity became more susceptible to both tobacco mosaic virus and potato virus x. thus, different rdrps may have distinc ... | 2003 | 12650452 |
| type-1 ribosome-inactivating protein from iris bulbs: a useful agronomic tool to engineer virus resistance? | to study the in planta antiviral activity of a type-1 ribosome-inactivating protein from iris bulbs, called irip, nicotiana tabacum cv. samsun nn was transformed with the irip sequence expressed under the control of the 35s cauliflower mosaic virus promoter. molecular analysis of the transgenic plants and characterization of the purified protein revealed that the recombinant irip from tobacco leaves has the same molecular structure and rna n-glycosidase activity as the native protein from iris b ... | 2003 | 12650622 |
| [effect of tobacco mosaic virus on the ultrastructure of leaf mesophyll cells of the pepper capsicuum anuum l]. | chlorotic areas of capsicuum anuum l. leaves infected with tobacco mosaic virus (tmv) have been investigated. pathological changes of chloroplasts were found out. swelling, more osmophilic plastoglobuli, loosened thylakoid structure were observed. it was shown that chloroplasts did not take part in the process of virus replication. some structural changes of mitochondria were discovered too. they were most tolerant to the virus infection in comparison with other organoids. | 2002 | 12664548 |
| induction of resistance and expression of defense-related genes in tobacco leaves infiltrated with ralstonia solanacearum. | ralstonia solanacearum 8107 (8107) is non-pathogenic to tobacco and elicits the hypersensitive response (hr). in nicotiana tabacum cv. samsun nn leaves infiltrated with 8107, acquired resistance to challenging tobacco mosaic virus (tmv) was induced 2-6 d after 8107-infiltration. hsr203j and hin1 genes were expressed only in the 8107-infiltrated area. on the other hand, the expression of pr-1a and pr-1b genes was not detected in the 8107-infiltrated area, but in areas other than that developing t ... | 2003 | 12668775 |
| a diterpene as an endogenous signal for the activation of defense responses to infection with tobacco mosaic virus and wounding in tobacco. | in pathogen-infected or wounded tobacco plants, the activation of wound-induced protein kinase (wipk), a tobacco mitogen-activated protein kinase, has been implicated in the defense response. however, no endogenous signal responsible for the activation has been identified. a wipk-activating substance was isolated from tobacco leaves and identified as (11e,13e)-labda-11,13-diene-8alpha,15-diol, designated waf-1. when applied in nanomolar concentrations to leaves, either natural waf-1 or chemicall ... | 2003 | 12671083 |
| a novel tmv-induced hot pepper cell wall protein gene (catin2) is associated with virus-specific hypersensitive response pathway. | incompatible plant-pathogen interactions result in the rapid cell death response known as hypersensitive response (hr) and activation of host defense related genes. to understand the cellular mechanism controlling defense response better, a novel pathogenesis-related (pr) gene and putative cell wall protein gene, catin2, was isolated through differential screening of a hot pepper cdna library and characterized. catin2 gene was locally and systemically induced in hot pepper plants upon tmv-p0 ino ... | 2003 | 12678557 |
| a lectin with mycelia differentiation and antiphytovirus activities from the edible mushroom agrocybe aegerita. | a lectin named aal has been purified from the fruiting bodies of the edible mushroom agrocybe aegerita. aal consisted of two identical subunits of 15.8 kda, its pi was about 3.8 determined by isoelectric focusing, and no carbohydrate was discerned. being treated by pyrogultamate aminopeptidase, the blocked n-terminus of aal was sequenced as qgvniyni. aal agglutinated human and animal erythrocytes regardless of blood type or animal species. its hemagglutinating activity was unaffected by acid or ... | 2003 | 12689522 |
| transfusion-associated tt virus co-infection in patients with hepatitis c virus is associated with type ii mixed cryoglobulinemia but not with b-cell non-hodgkin lymphoma. | to assess the prevalence of tt virus (tmv) infection in a series of patients with chronic hepatitis c virus (hcv) infection, with or without benign (mixed cryoglobulinemia) or malignant (b-cell non-hodgkin lymphoma (b-nhl)) lymphoproliferative disease. | 2003 | 12691541 |
| interaction between two mitogen-activated protein kinases during tobacco defense signaling. | plant mitogen-activated protein kinases (mapks) represented by tobacco wounding-induced protein kinase (wipk) have unique regulation at the level of transcription in response to stresses. by using transcriptional and translational inhibitors, it has been shown previously that wipk gene expression and de novo protein synthesis are required for the high-level activity of wipk in cells treated with elicitins from phytophthora spp. however, regulation of wipk expression and the role(s) of wipk in pl ... | 2003 | 12694591 |
| leaf mitochondria modulate whole cell redox homeostasis, set antioxidant capacity, and determine stress resistance through altered signaling and diurnal regulation. | to explore the role of plant mitochondria in the regulation of cellular redox homeostasis and stress resistance, we exploited a nicotiana sylvestris mitochondrial mutant. the cytoplasmic male-sterile mutant (cmsii) is impaired in complex i function and displays enhanced nonphosphorylating rotenone-insensitive [nad(p)h dehydrogenases] and cyanide-insensitive (alternative oxidase) respiration. loss of complex i function is not associated with increased oxidative stress, as shown by decreased leaf ... | 2003 | 12724545 |
| enhancement of virus-induced gene silencing through viral-based production of inverted-repeats. | plant virus-based vectors carrying sequences homologous to endogenous genes trigger silencing through a homology-dependent rna degradation mechanism. this phenomenon, called virus-induced gene silencing (vigs), has potential as a powerful reverse-genetics tool in functional genomic programmes through transient, loss-of-function screens. here, we describe a method to enhance the robustness of the vigs phenotype by increasing the level of dsrna molecule production, a critical step in the vigs resp ... | 2003 | 12753592 |
| expression of the baculovirus p35 protein in tobacco affects cell death progression and compromises n gene-mediated disease resistance response to tobacco mosaic virus. | the p35 protein from baculovirus is a broad-range caspase inhibitor and suppresses programmed cell death in animals. we report here the effects of transgenic expression in tobacco of the p35 protein during the hypersensitive response (hr). expression of p35 causes partial inhibition of nonhost hr triggered by bacteria and gene-for-gene hr triggered by virus. infection of p35-expressing tobacco plants with tobacco mosaic virus (tmv) disrupts n-mediated disease resistance, causing systemic spreadi ... | 2003 | 12795375 |
| pathogen-induced systemic plant signal triggers dna rearrangements. | plant genome stability is known to be affected by various abiotic environmental conditions, but little is known about the effect of pathogens. for example, exposure of maize plants to barley stripe mosaic virus seems to activate transposable elements and to cause mutations in the non-infected progeny of infected plants. the induction by barley stripe mosaic virus of an inherited effect may mean that the virus has a non-cell-autonomous influence on genome stability. infection with peronospora par ... | 2003 | 12802336 |
| misfolded plant virus proteins: elicitors and targets of ubiquitylation. | mutant tobacco mosaic virus (tmv) coat proteins (cps) with known amino acid replacements provide well defined examples of destabilized tertiary structures. here we show that misfolded tmv cps, but not functional wild-type cps, induce massive ubiquitylation in tobacco cells and that denatured, insoluble cp subunits are the main substrates of ubiquitin conjugation. as tmv cps can be easily manipulated they are unique tools to study the molecular basis of the plant cell's response to aberrant prote ... | 2003 | 12804781 |
| a mechanism of macroscopic (amorphous) aggregation of the tobacco mosaic virus coat protein. | to gain more insight into the mechanisms of heating-induced irreversible macroscopic aggregation of the tobacco mosaic virus (tmv) coat protein (cp), the effects of ph and ionic strength on this process were studied using turbidimetry, cd spectroscopy, and fluorescence spectroscopy. at 42 degrees c, the tmv cp passed very rapidly (in less than 15s) into a slightly unfolded conformation, presumably because heating disordered a segment of the subunit where the so-called hydrophobic girdle of the m ... | 2003 | 12818240 |
| vl position 34 is a key determinant for the engineering of stable antibodies with fast dissociation rates. | predictive engineering of antibodies exhibiting fast kinetic properties could provide reagents for biotechnological applications such as continuous monitoring of compounds or affinity chromatography. based on covariance analysis of murine germline antibody variable domains, we selected position l34 (kabat numbering) for mutational studies. this position is located at the vl/vh interface, at the base of the paratope but with limited antigen contacts, thus making it an attractive position for mild ... | 2003 | 12826730 |
| dielectric spectroscopy of tobacco mosaic virus. | the dielectric properties of the tobacco mosaic virus (tmv) have been measured using time domain dielectric spectroscopy (tdds) in the temperature range from 1 to 40 degrees c. a single dielectric dispersion is observed in the mhz range. the activation energy of the process is found to be in the range 1-2 kcal/mol. the experimental data could not be completely accounted for by current theoretical models, but evidence indicates that the dielectric loss arises from polarisation of charge on and ar ... | 2003 | 12829262 |
| signaling of systemic acquired resistance in tobacco depends on ethylene perception. | the hypersensitive interaction between tobacco mosaic virus (tmv) and tobacco results in accumulation of salicylic acid (sa), defense gene expression, and development of systemic acquired resistance (sar) in uninfected leaves. the plant hormones sa and ethylene have been implicated in sar. from a study with ethylene-insensitive (tetr) tobacco, we concluded that ethylene perception is required to generate the systemic signal molecules in tmv-infected leaves that trigger sa accumulation, defense g ... | 2003 | 12834399 |
| investigative proteomics: identification of an unknown plant virus from infected plants using mass spectrometry. | we describe the identification of a previously uncharacterized plant virus that is capable of infecting nicotiana spp. and arabidopsis thaliana. protein extracts were first prepared from leaf tissue of uninfected tobacco plants, and the proteins were visualized with two-dimensional electrophoresis (2-de). matching gels were then run using protein extracts of a tobacco plant infected with tobacco mosaic virus (tmv). after visual comparison, the proteins spots that were differentially expressed in ... | 2003 | 12837595 |
| high-throughput viral expression of cdna-green fluorescent protein fusions reveals novel subcellular addresses and identifies unique proteins that interact with plasmodesmata. | a strategy was developed for the high-throughput localization of unknown expressed proteins in nicotiana benthamiana. libraries of random, partial cdnas fused to the 5' or 3' end of the gene for green fluorescent protein (gfp) were expressed in planta using a vector based on tobacco mosaic virus. viral populations were screened en masse on inoculated leaves using a confocal microscope fitted with water-dipping lenses. each viral infection site expressed a unique cdna-gfp fusion, allowing several ... | 2003 | 12837943 |
| genetic modification of alternative respiration has differential effects on antimycin a-induced versus salicylic acid-induced resistance to tobacco mosaic virus. | salicylic acid (sa), a natural defensive signal chemical, and antimycin a, a cytochrome pathway inhibitor, induce resistance to tobacco mosaic virus (tmv). pharmacological evidence suggested signaling during resistance induction by both chemicals involved alternative oxidase (aox), sole component of the alternative respiratory pathway (ap). roles of the ap include regulation of intramitochondrial reactive oxygen species and maintenance of metabolic homeostasis. transgenic tobacco (nicotiana taba ... | 2003 | 12857832 |
| identification of a region of the tobacco mosaic virus 126- and 183-kilodalton replication proteins which binds specifically to the viral 3'-terminal trna-like structure. | uv irradiation of a mixture of an isolated tobacco mosaic virus (tmv; tomato strain l [tmv-l]) rna-dependent rna polymerase complex and the tmv-l rna 3'-terminal region (3'-tr) resulted in cross-linking of the tmv-l 126-kda replication protein to the tmv-l 3'-tr. using both escherichia coli-expressed proteins corresponding to parts of the 126-kda protein and mutants of the 3'-tr, the interacting sites were located to a 110-amino-acid region just downstream of the core methyltransferase domain in ... | 2003 | 12885885 |
| systemic movement of a tobamovirus requires host cell pectin methylesterase. | systemic movement of plant viruses through the host vasculature, one of the central events of the infection process, is essential for maximal viral accumulation and development of disease symptoms. the host plant proteins involved in this transport, however, remain unknown. here, we examined whether or not pectin methylesterase (pme), one of the few cellular proteins known to be involved in local, cell-to-cell movement of tobacco mosaic virus (tmv), is also required for the systemic spread of vi ... | 2003 | 12887589 |
| highly stable and efficient mrna templates for mrna-protein fusions and c-terminally labeled proteins. | for high-throughput in vitro protein selection using genotype (mrna)-phenotype (protein) fusion formation and c-terminal protein labeling as a post-selection analysis, it is important to improve the stability and efficiency of mrna templates for both technologies. here we describe an efficient single-strand ligation (90% of the input mrnas) using a fluorescein-conjugated polyethylene glycol puromycin (fluor-peg puro) spacer. this ligation provides a stable c-jun mrna with a flexible fluor-peg pu ... | 2003 | 12888530 |
| tritium planigraphy comparative structural study of tobacco mosaic virus and its mutant with altered host specificity. | spatial organization of wild-type (strain u1) tobacco mosaic virus (tmv) and of the temperature-sensitive tmv ts21-66 mutant was compared by tritium planigraphy. the ts21-66 mutant contains two substitutions in the coat protein (ile21-->thr and asp66-->gly) and, in contrast with u1, induces a hypersensitive response (formation of necroses) on the leaves of plants bearing a host resistance gene n' (for example nicotiana sylvestris); tmv u1 induces systemic infection (mosaic) on the leaves of such ... | 2003 | 12899688 |
| tobacco mosaic virus induced alterations in the gene expression profile of arabidopsis thaliana. | in this study, mrna profiles generated from cdna microarrays were used to identify gene expression changes in arabidopsis thaliana ecotype shahdara infected with tobacco mosaic virus (tmv). shahdara is a susceptible tmv host, permitting rapid accumulations of virus in both inoculated and systemic tissues, accompanied by defined disease symptoms that include stunting, necrosis, and leaf curling. gene expression profiles were monitored in whole tissues of inoculated leaves at four days postinocula ... | 2003 | 12906112 |
| mpb2c, a microtubule-associated plant protein binds to and interferes with cell-to-cell transport of tobacco mosaic virus movement protein. | the movement protein of tobacco mosaic virus, mp30, mediates viral cell-to-cell transport via plasmodesmata. the complex mp30 intra- and intercellular distribution pattern includes localization to the endoplasmic reticulum, cytoplasmic bodies, microtubules, and plasmodesmata and likely requires interaction with plant endogenous factors. we have identified and analyzed an mp30-interacting protein, mpb2c, from the host plant nicotiana tabacum. mpb2c constitutes a previously uncharacterized microtu ... | 2003 | 12913144 |
| induction of hypersensitive cell death by hydrogen peroxide produced through polyamine degradation in tobacco plants. | screening immediate-early responding genes during the hypersensitive response (hr) against tobacco mosaic virus infection in tobacco (nicotiana tabacum) plants, we identified a gene encoding ornithine decarboxylase. subsequent analyses showed that other genes involved in polyamine biosynthesis were also up-regulated, resulting in the accumulation of polyamines in apoplasts of tobacco mosaic virus-infected leaves. inhibitors of polyamine biosynthesis, alpha-difluoromethyl-ornithine, however, supp ... | 2003 | 12913153 |