| a novel strategy for the expression of foreign genes from plant virus vectors. | potato virus x (pvx)-based vector constructs were generated to investigate the use of an internal ribosome entry site (ires) sequence to direct translation of a viral gene. the 148-nucleotide irescp sequence from a crucifer-infecting strain of tobacco mosaic virus was used to direct expression of the pvx coat protein (cp). the ires was inserted downstream of the gene encoding green fluorescent protein (gfp) and upstream of the pvx cp, in either sense or antisense orientation, such that cp expres ... | 2001 | 11165252 |
| satellite tobacco mosaic virus rna: structure and implications for assembly. | the initial appearance of 45% of the single-stranded rna of satellite tobacco mosaic virus in electron density maps suggested the entire rna conformation could be delineated. subsequent work has localized nearly 80% of the rna as stem-loop elements. connection of the stem-loops in the most efficient manner produces a persuasive model for the encapsidated rna. this arrangement has significant implications for virus assembly and for the essential role of rna. | 2001 | 11179893 |
| predicting the kinetics of peptide-antibody interactions using a multivariate experimental design of sequence and chemical space. | a multivariate approach involving modifications in peptide sequence and chemical buffer medium was used as an attempt to predict the kinetics of peptide-antibody interactions. using a biacore system the kinetic parameters of the interaction of fab 57p with 18 peptide analogues of an epitope of tobacco mosaic virus protein were characterized in 20 buffers of various ph values and containing different chemical additives (nacl, urea, edta, kscn and dmso). for multivariate peptide design, three amin ... | 2001 | 11180562 |
| [preparation of monoclonal antibodies to barley yellow mosaic virus]. | using hybridoma techniques, six hybridoma celllines: 4d6, 4d4, 4f10, 3h6, 3h8 and 4e9 secreting monoclonal antibodies to shanghai isolate of barley yellow mosaic virus (baymv) were prepared by fusion between myeloma cells ns-1 and spleen cells of balb/c mouse immunized with baymv. the subclasses of monoclonal antibodies obtained belong to igg2a. the cross-reaction test with different viruses (smv, tmv and three isolates of tumv) showed that six monoclonal antibodies were specific to baymv. the t ... | 1997 | 11189368 |
| [construction and application of an escherichia coli high effective expression vector with an enhancer]. | in this study, we constructed a high effective fusion expression-vector in e. coli. this vector, pto-t7, was characterized as: (1) an enhancer from tobacco mosaic virus (tmv), omega sequence, was ligated in front of a t7 promoter in the regulatory sequence; (2) the multi-cloning sites include eight restriction enzyme sites. it can facilitate fusion or nonfusion expression; (3) the n terminal of a fusion protein starts with the first 12 amino acids of t7 gene 10, and the c terminal is the hexahis ... | 2000 | 11191761 |
| transient accumulation of jasmonic acid during the synchronized hypersensitive cell death in tobacco mosaic virus-infected tobacco leaves. | jasmonic acid (ja) transiently accumulated during temperature-dependent synchronous necrotic lesion formation in tobacco mosaic virus-infected tobacco leaves. the accumulation of ja was preceded by activation of a tobacco mitogen-activated protein kinase, wipk, which functions upstream of ja in wound signal transduction pathways. | 2001 | 11204791 |
| development of a plant-derived subunit vaccine candidate against hepatitis c virus. | hepatitis c virus (hcv) is a major cause of acute and chronic hepatitis with over 180 million cases worldwide. vaccine development for hcv has been difficult. presently, the virus cannot be grown in tissue culture and there is no vaccine or effective therapy against this virus. in this research, we describe the development of an experimental plant-derived subunit vaccine against hcv. a tobamoviral vector was engineered to encode a consensus sequence of hypervariable region 1 (hvr1), a potential ... | 2000 | 11205105 |
| constitutive expression of interferon-induced human mxa protein in transgenic tobacco plants does not confer resistance to a variety of rna viruses. | mxa is a key component in the interferon-induced antiviral defense in humans. after viral infections, mxa is rapidly induced and accumulates in the cytoplasm. the multiplication of many rna viruses, including all bunyaviruses tested so far, is inhibited by mxa. these findings prompted us to express mxa in plants in an attempt to create resistance to tospoviruses. here, we report the generation of transgenic tobacco plants that constitutively express mxa under the control of the 35 s cauliflower ... | 2000 | 11206971 |
| role of p30 in replication and spread of tmv. | the p30 movement protein (mp) of tobacco mosaic virus is essential for distribution of sites of replication within infected cells and for cell-cell spread of infection. mp is an integral membrane protein and in early and mid-stages of infection causes severe disruption of the cortical endoplasmic reticulum (er). mp also associates with microtubules, and in late stages is targeted for degradation by the 26s proteosome. during these stages, the er regains its normal pre-infection configuration. vi ... | 2000 | 11208141 |
| delineation of a linear epitope by multiple peptide synthesis and phage display. | two different approaches, the phage display technique and the spot peptide synthesis on cellulose membranes, were used to identify sequences recognized by fab 57p, specific for tobacco mosaic virus protein (tmvp), and define the preferred chemical composition of a functional epitope. kinetic measurements of the interaction between peptide variants and the antibody fragment were used to further refine the molecular basis of binding activity. our results show that the functional epitope of fab 57p ... | 2001 | 11226482 |
| macroscopic aggregation of tobacco mosaic virus coat protein. | the relationship between processes of thermal denaturation and heat-induced aggregation of tobacco mosaic virus (tmv) coat protein (cp) was studied. judging from differential scanning calorimetry "melting" curves, tmv cp in the form of a trimer-pentamer mixture ("4s-protein") has very low thermal stability, with a transition temperature at about 40 degrees c. thermally denatured tmv cp displayed high propensity for large (macroscopic) aggregate formation. tmv cp macroscopic aggregation was stron ... | 2001 | 11255122 |
| tobacco mosaic virus rna as genetic determinant: genesis of a discovery. | it is generally held that the american geneticists alfred hershey and martha chase were the first to elucidate, in 1952, the genetic functions of phage dna. the discovery of the genetic functions of rna in a plant virus (tobacco mosaic virus, tmv) is commonly attributed to the american plant virologist heinz fraenkel-conrat, and to the germans alfred gierer and gerhard schramm, who came to the same conclusion independently in 1956. in reality, the first understandings dated back to about 1940, w ... | 2000 | 11256209 |
| a hot pepper cdna encoding a pathogenesis-related protein 4 is induced during the resistance response to tobacco mosaic virus. | hot pepper (capsicum annuum) plants exhibit a hypersensitive response (hr) against infection by many tobamoviruses. a clone (capr-4) encoding a putative pathogenesis-related protein 4 was isolated by differential screening of a cdna library prepared from resistant pepper plant leaves inoculated with tobacco mosaic virus (tmv) pathotype p0. the predicted amino acid sequence of capr-4 is very similar to those of other plant pr-4s. southern blot analysis showed that small gene families of pr-4-rela ... | 2001 | 11266114 |
| identification and functional analysis of an interaction between domains of the 126/183-kda replicase-associated proteins of tobacco mosaic virus. | the tobacco mosaic virus (tmv) 126-kda and read-through 183-kda replicase-associated proteins have been shown to interact [watanabe, t., honda, a., iwata, a., ueda, s., hibi, t., ishihama, a. (1999). j. virol. 73, 2633-2640]. to identify and investigate the sequence required for this interaction, five segments covering different portions of the 126/183-kda open reading frame, including the methyl-transferase, intervening region (ir), helicase-like (hel), and polymerase domains, were screened via ... | 2001 | 11289814 |
| systemic spread of an rna insect virus in plants expressing plant viral movement protein genes. | flock house virus (fhv), a single-stranded rna insect virus, has previously been reported to cross the kingdom barrier and replicate in barley protoplasts and in inoculated leaves of several plant species [selling, b. h., allison, r. f. & kaesberg, p. (1990) proc. natl. acad. sci. usa 87, 434-438]. there was no systemic movement of fhv in plants. we tested the ability of movement proteins (mps) of plant viruses to provide movement functions and cause systemic spread of fhv in plants. we compared ... | 2001 | 11296259 |
| non-targeted and targeted protein movement through plasmodesmata in leaves in different developmental and physiological states. | plant cells rely on plasmodesmata for intercellular transport of small signaling molecules as well as larger informational macromolecules such as proteins. a green fluorescent protein (gfp) reporter and low-pressure microprojectile bombardment were used to quantify the degree of symplastic continuity between cells of the leaf at different developmental stages and under different growth conditions. plasmodesmata were observed to be closed to the transport of gfp or dilated to allow the traffic of ... | 2001 | 11299360 |
| rapid production of recombinant allergens in nicotiana benthamiana and their impact on diagnosis and therapy. | type i allergies are immunological disorders that afflict a quarter of the world's population. recombinant allergens have improved the diagnosis of allergic diseases and allow the formulation of new therapeutic approaches. over 50% of all allergens are of plant origin. | 2001 | 11306923 |
| biophysical studies on the rna cores of satellite tobacco mosaic virus. | satellite tobacco mosaic virus (stmv) was probed using a variety of proteases. consequences of the degradation were analyzed using gel electrophoresis, quasi-elastic light scattering (qels), and atomic force microscopy (afm). proteolysis rates of 30 minutes for complete degradation of the protein capsid, up to many hours, were investigated. with each protease, degradation of virions 17 nm in diameter was shown by qels to result in particles of 10 nm diameter, which is that of the rna core observ ... | 2001 | 11325736 |
| an early tobacco mosaic virus-induced oxidative burst in tobacco indicates extracellular perception of the virus coat protein. | induction of reactive oxygen species (ros) was observed within seconds of the addition of exogenous tobacco mosaic virus (tmv) to the outside of tobacco (nicotiana tabacum cv samsun nn, en, or nn) epidermal cells. cell death was correlated with ros production. infectivity of the tmv virus was not a prerequisite for this elicitation and isolated coat protein (cp) subunits could also elicit the fast oxidative burst. the rapid induction of ros was prevented by both inhibitors of plant signal transd ... | 2001 | 11351074 |
| an important role of an inducible rna-dependent rna polymerase in plant antiviral defense. | plants contain rna-dependent rna polymerase (rdrp) activities that synthesize short crnas by using cellular or viral rnas as templates. during studies of salicylic acid (sa)-induced resistance to viral pathogens, we recently found that the activity of a tobacco rdrp was increased in virus-infected or sa-treated plants. biologically active sa analogs capable of activating plant defense response also induced the rdrp activity, whereas biologically inactive analogs did not. a tobacco rdrp gene, ntr ... | 2001 | 11353867 |
| conundrum of the lack of defective rnas (drnas) associated with tobamovirus infections: drnas that can move are not replicated by the wild-type virus; drnas that are replicated by the wild-type virus do not move. | two classes of artificially constructed defective rnas (drnas) of tobacco mosaic virus (tmv) were examined in planta with helper viruses that expressed one (183 kda) or both (126 and 183 kda) of the replicase-associated proteins. the first class of artificially constructed drnas had the helicase and polymerase (pol) domains deleted; the second had an intact 126-kda protein open reading frame (orf). despite extremely high levels of replication in protoplasts, the first class of drnas did not accu ... | 2001 | 11356959 |
| a comparison of the solution structures of tobacco rattle and tobacco mosaic viruses from raman optical activity. | vibrational raman optical activity (roa) spectra of tobacco rattle virus (trv) and tobacco mosaic virus (tmv) were measured and compared with a view to obtaining new information about the coat protein subunit structure of trv. a sharp strong positive band observed at approximately 1344 cm(-1) in the roa spectra of the two viruses is evidence that both contain a significant amount of a hydrated form of alpha-helix, but more in trv than in tmv. although the roa spectrum of tmv shows significant po ... | 2001 | 11369896 |
| visualization by atomic force microscopy of tobacco mosaic virus movement protein-rna complexes formed in vitro. | the structure of complexes formed in vitro by tobacco mosaic virus (tmv)-coded movement protein (mp) with tmv rna and short (890 nt) synthetic rna transcripts was visualized by atomic force microscopy on a mica surface. mp molecules were found to be distributed along the chain of rna and the structure of mp-rna complexes depended on the molar mp:rna ratios at which the complexes were formed. a rise in the molar mp:tmv rna ratio from 20:1 to 60-100:1 resulted in an increase in the density of the ... | 2001 | 11369897 |
| ordered association of tobacco mosaic virus in the presence of divalent metal ions. | the formation of ordered aggregates of tobacco mosaic virus (tmv) in the presence of divalent metal ions has been studied in concentrated (1-25 mg/ml) solutions of the virus. the divalent metal cations cd2+, zn2+, pb2+, cu2+, and ni2+ have been found to promote tmv precipitation from solution at a critical concentration ccrit, which for a given metal depends on the ph and the ionic strength of the solution, but is largely independent of the virus concentration. the tmv precipitate behaves as a n ... | 2001 | 11374586 |
| assessment of recombinants that arise from the use of a tmv-based transient expression vector. | a potential use of virus-based transient expression vectors is the large-scale production of commercial specialty products, which would require the inoculation of many acres of plants with the viral vector. however, there are several concerns about the widespread use of virus-based vectors. among these are the spread of the engineered virus to susceptible plants and the generation and persistence of recombinant viruses in the environment. using a tobacco mosaic virus (tmv)-based transient gene e ... | 2001 | 11384218 |
| structural transitions of satellite tobacco mosaic virus particles. | satellite tobacco mosaic virus (stmv) can undergo at least two physical transitions that significantly alter its mechanical and structural characteristics. at high ph the 17-nm stmv particles expand radially by about 5 a to yield particles having diameters of about 18 nm. this ph-induced transition is further promoted by aging of the virions and degradation of the rna, so that swollen particles ultimately appear even at neutral ph. while the native 17-nm particles crystallize as orthorhombic or ... | 2001 | 11384222 |
| the suppressor of transgene rna silencing encoded by cucumber mosaic virus interferes with salicylic acid-mediated virus resistance. | the cucumber mosaic virus (cmv)-encoded 2b protein (cmv2b) is a nuclear protein that suppresses transgene rna silencing in nicotiana benthamiana. cmv2b is an important virulence determinant but nonessential for systemic spread in n. glutinosa, in contrast to its indispensable role for systemic infections in cucumber. here, we report that cmv2b became essential for systemic infections in older n. glutinosa plants or in young seedlings pretreated with salicylic acid (sa). expression of cmv2b from ... | 2001 | 11386367 |
| production of 6-methylsalicylic acid by expression of a fungal polyketide synthase activates disease resistance in tobacco. | salicylic acid (sa) has been shown to act as a signal molecule that is produced by many plants subsequent to the recognition of potentially pathogenic microbes. increases in levels of sa often trigger the activation of plant defenses and can result in increased resistance to subsequent challenge by pathogens. we observed that the polyketide 6-methylsalicylic acid (6-mesa), a compound that apparently is not endogenous to tobacco, can mimic sa. tobacco leaves treated with 6-mesa show enhanced accu ... | 2001 | 11402168 |
| virus-specific mrna capping enzyme encoded by hepatitis e virus. | hepatitis e virus (hev), a positive-strand rna virus, is an important causative agent of waterborne hepatitis. expression of cdna (encoding amino acids 1 to 979 of hev nonstructural open reading frame 1) in insect cells resulted in synthesis of a 110-kda protein (p110), a fraction of which was proteolytically processed to an 80-kda protein. p110 was tightly bound to cytoplasmic membranes, from which it could be released by detergents. immunopurified p110 catalyzed transfer of a methyl group from ... | 2001 | 11413290 |
| insertion of capsid proteins from nonenveloped viruses into the retroviral budding pathway. | retroviral gag proteins direct the assembly and release of virus particles from the plasma membrane. the budding machinery consists of three small domains, the m (membrane-binding), i (interaction), and l (late or "pinching-off") domains. in addition, gag proteins contain sequences that control particle size. for rous sarcoma virus (rsv), the size determinant maps to the capsid (ca)-spacer peptide (sp) sequence, but it functions only when i domains are present to enable particles of normal densi ... | 2001 | 11413320 |
| genetic diversity in rna virus quasispecies is controlled by host-virus interactions. | many rna viruses have genetically diverse populations known as quasispecies. important biological characteristics may be related to the levels of diversity in the quasispecies (quasispecies cloud size), including adaptability and host range. previous work using tobacco mosaic virus and cucumber mosaic virus indicated that evolutionarily related viruses have very different levels of diversity in a common host. the quasispecies cloud size for these viruses remained constant throughout serial passa ... | 2001 | 11413324 |
| plants expressing tomato golden mosaic virus al2 or beet curly top virus l2 transgenes show enhanced susceptibility to infection by dna and rna viruses. | the al2 gene of the geminivirus tomato golden mosaic virus (tgmv) encodes a transcriptional activator protein (trap) that is required for efficient expression of the viral coat protein (cp) and br1 gene promoters. in contrast, l2, the positional homolog of al2 in the related beet curly top virus (bctv), is not required for cp expression, raising questions about the functional relationship between the al2 and l2 gene products. in this study, transgenic nicotiana benthamiana and n. tabacum var. sa ... | 2001 | 11414806 |
| a dysfunctional movement protein of tobacco mosaic virus interferes with targeting of wild-type movement protein to microtubules. | the tobacco mosaic virus (tmv) movement protein (mptmv) mediates cell-to-cell viral trafficking by altering properties of the plasmodesmata (pd) in infected cells. during the infection cycle, mptmv becomes transiently associated with endomembranes, microfilaments, and microtubules (mt). it has been shown that the cell-to-cell spread of tmv is reduced in plants expressing the dysfunctional mp mutant mpnt-1. to expand our understanding of the mp function, we analyzed events occurring during the in ... | 2001 | 11437263 |
| mutants of tobacco mosaic virus with temperature-sensitive coat proteins induce heat shock response in tobacco leaves. | we analyzed, with respect to heat shock proteins (hsps), systemically reacting tobacco leaves inoculated with tobacco mosaic virus (tmv), wild-type vulgare, and temperature-sensitive coat protein (cp) mutants ni 118 (p20l) and flavum (d19a), kept at 23 or 30 degrees c. hsp18 and hsp70 mrnas and proteins were induced with temperature-sensitive cp mutants after 1 to 2 days at 30 degrees c. after 4 to 6 days, hsp70 was also induced at 23 degrees c. the induction of hsps paralleled the amount of ins ... | 2001 | 11437266 |
| rapid two-step purification of a recombinant mouse fab fragment expressed in escherichia coli. | we report a rapid, large-scale process for the purification of a recombinant fab fragment specific for the tobacco mosaic virus coat protein (fab57p). the fragment is expressed periplasmically in escherichia coli. the expression level was optimized in 0.3-l fermentors. the highest levels were obtained using the following conditions: (1) low postinduction temperature (21 degrees c), (2) combined use of two beta-lactam antibiotics (carbenicillin and ampicillin), (3) iptg concentration 0.1 mm, (4) ... | 2001 | 11437609 |
| collateral gene expression changes induced by distinct plant viruses during the hypersensitive resistance reaction in chenopodium amaranticolor. | hypersensitive reactions to plant diseases are typically mediated by r genes. many r genes that have been cloned only confer resistance to a particular pathogen. however, chenopodium spp. have multivirus hypersensitive resistance, thus making the understanding of this broad-spectrum resistance mechanism attractive. using tobacco mosaic virus (tmv) tagged with green fluorescent protein to follow infection over time, cdna-aflp to find genes up-regulated during virus infection in c. amaranticolor a ... | 2001 | 11439122 |
| [differences in the spatial structure of an envelope protein from tobacco mosaic virus and its mutant, detected by tritium planigraphy]. | mutant ts21-66 of the tobacco mosaic virus (tmv) differs from the wild-type tmv-u1 by two mutations (ile-21-->thr and asp-66-->gly) in the coat protein (cp) gene and in symptoms produced in infected n' plants. the cp structure in tmv-u1 and ts21-66 virions was probed by tritium planigraphy. compared with the wild-type cp, labeling of the n-terminal region of mutant cp was half as high and suggested its greater shielding. a role of this cp region in virus interactions with the n' resistance syste ... | 2001 | 11443934 |
| flow dichroic spectra of tobacco mosaic virus and their protein assemblies. | ultraviolet flow dichroisms of tobacco mosaic virus (tmv), tmv-rna and tmv-protein were measured using three strains of tmv. 1. large positive dichroisms were observed with three strains of tmv, namely ordinary, bean form of bean, and tomato strains (tmv-om, tmv-b and tmv-t, respectively) at about 255, 276, 284 and 290 nm. the positive dichroisms were confirmed with reconstituted protein assemblies of tmv-om and tmv-b at about 276, 284 and 290 nm where tyrosine and tryptophan residues of these p ... | 1971 | 11452381 |
| circular dichroism studies on coat proteins of some strains and mutants of tobacco mosaic virus. | 1. tobacco mosaic virus (tmv) protein has in near ultraviolet a complex but well resolved circular dichroism (cd) spectrum at room temperature. there are seven positive bands at 248, 252, 257, 265, 274, 281 and 291 nm, and a negative one at 296 nm. the cd spectrum is ph-dependent. the shape of the ph-dependence curves and the comparison with cd spectra of model compounds suggest that the bands at 248, 252 and 257 nm are mainly caused by phenylalanyl, those at 265, 274 and 281 nm by tyrosyl, and ... | 1971 | 11452869 |
| transcriptionally and post-transcriptionally regulated response of 13 calmodulin genes to tobacco mosaic virus-induced cell death and wounding in tobacco plant. | we isolated 13 tobacco calmodulin (cam) genes, ntcam1-13, and analyzed their expression profile in response to pathogen infection and wounding using specific dna probes for individual cam genes and specific antibodies for cam proteins in groups i (ntcam1/2), ii (ntcam3/4/5/6/7/8/11/12 and 9/10) and iii (ntcam13), respectively. synchronous cell death in tobacco mosaic virus (tmv)-infected n-gene-containing tobacco leaves accompanied a predominant accumulation of ntcam1, 2 and 13 transcripts and n ... | 2001 | 11453984 |
| self-repair of biological fibers catalyzed by the surface of a virus crystal. | helical fibers, presumably proteinaceous and of microbial origin, have been visualized by atomic force microscopy on the surfaces of crystals of satellite tobacco mosaic virus. if the crystals are growing, then the fibers are incorporated intact into the crystal lattice. if broken on the crystal surface, then within a few minutes, the fibers self-reassemble to reestablish continuity. this, we believe, is the first observation of such a crystal surface-catalyzed repair of a biological structure. ... | 2001 | 11455612 |
| superoxide production by plant homologues of the gp91(phox) nadph oxidase. modulation of activity by calcium and by tobacco mosaic virus infection. | genes encoding homologs of the gp91(phox) subunit of the plasma membrane nadph oxidase complex have been identified in plants and are hypothesized to be a source of reactive oxygen species during defense responses. however, the direct involvement of the gene products in superoxide (o(2)(-)) production has yet to be shown. a novel activity gel assay based on protein fractionation in native or sodium dodecyl sulfate (sds)-denaturing polyacrylamide gels was developed. in native polyacrylamide gel e ... | 2001 | 11457979 |
| in vivo detection of tobacco mosaic virus-induced local and systemic oxidative burst by electron paramagnetic resonance spectroscopy. | this is the first demonstration that tobacco mosaic virus-induced oxidative stress in a necrotic host plant is signalled by an elevated level of monodehydroascorbate (mda) radicals detected by electron paramagnetic resonance spectroscopy. furthermore, systemic acquired resistance induced in remote leaves of xanthi-nc tobacco is also associated with stimulated mda signals indicative of a microoxidative burst. | 2001 | 11479386 |
| umbravirus gene expression helps potato leafroll virus to invade mesophyll tissues and to be transmitted mechanically between plants. | potato leafroll virus (plrv) was mechanically transmissible when inocula also contained the umbravirus pea enation mosaic virus-2 (pemv-2). in plants infected with plrv and pemv-2, plrv accumulated in clusters of mesophyll cells in both inoculated and systemically infected leaves. no transmissions were obtained by coinoculation with potato virus y, potato virus x (pvx), tobacco mosaic virus, or cucumber mosaic virus (cmv), although plrv was transmissible from mixtures with cmv(orf4) (a recombina ... | 2001 | 11485404 |
| secretion of biologically active glycoforms of bovine follicle stimulating hormone in plants. | we chose the follicle stimulating hormone (fsh), a pituitary heterodimeric glycoprotein hormone, as a model to assess the ability of the plant cell to express a recombinant protein that requires extensive n-glycosylation for subunit folding and assembly, intracellular trafficking, signal transduction and circulatory stability. a tobacco mosaic virus (tmv) based transient expression system was used to express a single-chain (sc) version of bovine fsh in the tobacco related species nicotiana benth ... | 2001 | 11502219 |
| tobamovirus replicase coding region is involved in cell-to-cell movement. | tobacco mosaic virus (tmv) encodes a 30-kda movement protein (mp) which enables viral movement from cell to cell. it is, however, unclear whether the 126- and 183-kda replicase proteins are involved in the cell-to-cell movement of tmv. in the course of our studies into tmv-r, a strain with a host range different from that of tmv-u1, we have obtained an interesting chimeric virus, ur-hel. the amino acid sequence differences between ur-hel and tmv-u1 are located only in the helicase-like domain of ... | 2001 | 11507227 |
| survival rates of some terrestrial microorganisms under simulated space conditions. | in connection with planetary quarantine, we have been studying the survival rates of nine species of terrestrial microorganisms (viruses, bacteria, yeasts, fungi, etc.) under simulated interstellar conditions. if common terrestrial microorganisms cannot survive in space even for short periods, we can greatly reduce expenditure for sterilizing space probes. the interstellar environment in the solar system has been simulated by low temperature, high vacuum (77 k, 4 x 10(-6) torr), and protons irra ... | 1992 | 11538148 |
| studies in the search for life on mars. | the ability of living organisms to survive extraterrestrial conditions has implications for the origins of life in the solar system. we have therefore studied the survival of viruses, bacteria, yeast, and fungi under simulated martian conditions. the environment on mars was simulated by low temperature, proton irradiation, ultraviolet irradiation, and simulated martian atmosphere (co2 95.46%, n2 2.7%, water vapor 0.03%) in a special cryostat. after exposure to these conditions, tobacco mosaic ... | 1995 | 11539227 |
| planetary quarantine in the solar system. survival rates of some terrestrial organisms under simulated space conditions by proton irradiation. | we have been studying the survival rates of some species of terrestrial unicellular and multicellular organism (viruses, bacteria, yeasts, fungi, algae, etc.) under simulated interstellar conditions, in connection with planetary quarantine. the interstellar environment in the solar system has been simulated by low temperature, high vacuum (77 k, 4 x 10(-8) torr), and proton irradiation from a van de graaff generator. after exposure to a barrage of protons corresponding to about 250 years of irra ... | 1993 | 11541644 |
| induction of a hypersensitive response by chimeric helicase sequences of tobamoviruses u1 and ob in n-carrying tobacco. | recently, the helicase domain of the tobacco mosaic virus (tmv)-u1 replicase proteins (designated morehel:u1) was identified as the elicitor of the n gene-mediated hypersensitive response (hr) in tobacco. in this study, we used agroinfiltration to express the equivalent morehel domain of the non-hr-inducing tobamovirus strain tmv-ob. it appeared that this morehel:ob sequence did not elicit a hr in n gene-carrying tobacco. both morehel sequences were divided into eight subdomains, and chimeras of ... | 2001 | 11551073 |
| in situ spatial organization of potato virus a coat protein subunits as assessed by tritium bombardment. | potato virus a (pva) particles were bombarded with thermally activated tritium atoms, and the intramolecular distribution of the label in the amino acids of the coat protein was determined to assess their in situ steric accessibility. this method revealed that the n-terminal 15 amino acids of the pva coat protein and a region comprising amino acids 27 to 50 are the most accessible at the particle surface to labeling with tritium atoms. a model of the spatial arrangement of the pva coat protein p ... | 2001 | 11559802 |
| [roles of negative charge interactions in the self-assembly mechanism of tobacco mosaic virus]. | | 2001 | 11565267 |
| [discovery of the first virus, the tobacco mosaic virus: 1892 or 1898?]. | two scientists contributed to the discovery of the first virus, tobacco mosaic virus. ivanoski reported in 1892 that extracts from infected leaves were still infectious after filtration through a chamberland filter-candle. bacteria are retained by such filters, a new world was discovered: filterable pathogens. however, ivanovski probably did not grasp the full meaning of his discovery. beijerinck, in 1898, was the first to call 'virus', the incitant of the tobacco mosaic. he showed that the inci ... | 2001 | 11570281 |
| umbravirus-encoded proteins both stabilize heterologous viral rna and mediate its systemic movement in some plant species. | the proteins encoded by open reading frame 3 (orf3) of the umbraviruses pea enation mosaic virus-2 and tobacco mottle virus, like that of groundnut rosette virus, mediated the movement of viral rna through the phloem of infected nicotiana benthamiana or n. clevelandii plants when they were expressed from chimeric tobacco mosaic virus in place of the coat protein. however, these chimeras did not move systemically in n. tabacum. in lysates of n. benthamiana or n. tabacum protoplasts, the chimeric ... | 2001 | 11601910 |
| expression of the gene for a small gtp binding protein in transgenic tobacco elevates endogenous cytokinin levels, abnormally induces salicylic acid in response to wounding, and increases resistance to tobacco mosaic virus infection. | tobacco plants transformed with rgp1, a gene encoding a ras-related small gtp binding protein, were previously shown to exhibit a distinct reduction in apical dominance with increased tillering. these abnormal pheno-types were later found to be associated with elevated levels of endogenous cytokinins (zeatin and zeatin riboside). analysis of the expression of several genes known to be affected by cytokinins identified a clear increase in the mrna levels of genes encoding acidic pathogenesis-rela ... | 1994 | 11607497 |
| biosynthesis and metabolism of salicylic acid. | pathways of salicylic acid (sa) biosynthesis and metabolism in tobacco have been recently identified. sa, an endogenous regulator of disease resistance, is a product of phenylpropanoid metabolism formed via decarboxylation of trans-cinnamic acid to benzoic acid and its subsequent 2-hydroxylation to sa. in tobacco mosaic virus-inoculated tobacco leaves, newly synthesized sa is rapidly metabolized to sa o-beta-d-glucoside and methyl salicylate. two key enzymes involved in sa biosynthesis and metab ... | 1995 | 11607533 |
| induction, modification, and transduction of the salicylic acid signal in plant defense responses. | studies in our laboratory as well as others strongly suggest that salicylic acid (sa) plays an important signaling role in plant defense against pathogens. we have found that increases in endogenous sa levels correlates with both resistance of tobacco to infection with tobacco mosaic virus and induction of defense-related genes such as that encoding pathogenesis-related protein 1 (pr-1). some of this newly synthesized sa was conjugated to glucose to form sa beta-glucoside. a cell wall-associated ... | 1995 | 11607539 |
| involvement of small gtp-binding proteins in defense signal-transduction pathways of higher plants. | small gtp-binding proteins play a critical role in the regulation of a range of cellular processes--including growth, differentiation, and intracellular transportation. previously, we isolated a gene, rgp1, encoding a small gtp-binding protein, by differential screening of a rice cdna library with probe dnas from rice tissues treated with or without 5-azacytidine, a powerful inhibitor of dna methylation. to determine the physiological role of rgp1, the coding region was introduced into tobacco p ... | 1995 | 11607540 |
| two inducers of plant defense responses, 2,6-dichloroisonicotinec acid and salicylic acid, inhibit catalase activity in tobacco. | 2,6-dichloroisonicotinic acid (ina) and salicylic acid (sa) are potent inducers of plant defense responses including the synthesis of pathogenesis-related (pr) proteins and the development of enhanced disease resistance. a soluble sa-binding protein has been purified from tobacco with an affinity and specificity of binding that suggest it is a sa receptor. recently, this protein has been shown to be a catalase whose enzymatic activity is inhibited by sa binding. we have proposed that the resulti ... | 1995 | 11607566 |
| [a brief history of discovering virus]. | tobacco mosaic virus plays a very important role in the discovery of virus and several pioneers made contributions to the developmental process of virology, through which the brief history of discovery of virus can be traced. | 2000 | 11624646 |
| functions of the 3'-untranslated regions of positive strand rna viral genomes. | positive strand rna viral genomes are unique in the viral world in serving a dual role as mrna and replicon. since the origin of the minus-strand rna replication intermediate is at the 3'-end of the genome, the 3'-untranslated region (utr) clearly plays a role in viral rna replication. the messenger role of this same rna likely places functional demands on the 3'-utr to serve roles typical of cellular mrnas, including the regulation of rna stability and translation. current understanding indicat ... | 1999 | 11701820 |
| advances in understanding plant viruses and virus diseases. | plant viruses have had an impact on the science of virology and on plant pathology ever since the virus concept was discovered with tobacco mosaic virus at the end of the nineteenth century. in this review, we highlight those discoveries. we have divided plant virus research into a "classical discovery period" from 1883-1951 in which the findings were very descriptive; an "early molecular era" from 1952 to about 1983, in which information was developed that described further properties of the vi ... | 2000 | 11701839 |
| induction of a pepper cdna encoding sar8.2 protein during the resistance response to tobacco mosaic virus. | a cdna library was constructed with mrna extracted from tmv resistant hot pepper plants 24 and 48 h after inoculation by tmv. the library was screened differentially with radio-labeled cdna synthesized with mrna from the leaves of either tmv-inoculated or mock-inoculated hot pepper plants. casar8.2 clone was one of the clones isolated by this differential screening. the predicted amino acid sequence of casar8.2 has a homology of 52% similarity to that of tobacco sar8.2 genes. southern blot analy ... | 2001 | 11710530 |
| detection of the 5'-cap structure of messenger rnas with the use of the cap-jumping approach. | an effective procedure for specific determination of the cap structure at the 5'-terminus of mrna and for isolation of the corresponding full-length cdna has been developed. the procedure involves covalent attachment of an oligonucleotide template extender to the 5'-cap structure of mrna followed by rt-pcr using m-mlv superscript ii reverse transcriptase. in the course of reverse transcription, the enzyme 'jumps over' the cap structure and includes the sequence complementary to the oligonucleoti ... | 2001 | 11713326 |
| evidence for rna-mediated defence effects on the accumulation of potato leafroll virus. | in plants infected with potato leafroll virus (plrv), or other luteoviruses, infection is very largely confined to cells in the vascular system. even in tobacco plants transformed with plrv full-length cdna, in which all mesophyll cells should synthesize infectious plrv rna transcripts, only a minority of the mesophyll cells accumulate detectable amounts of virus. we have explored this phenomenon further by transforming a better plrv host, nicotiana benthamiana, with the same transgene, by super ... | 2001 | 11714988 |
| a history of plant virology. mendelian genetics and resistance of plants to viruses. | virology was borne at the end of the nineteenth century, some years before the re-discovery of the so-called "mendel's laws". the rapid development of genetics was helpful to horticulturists and plant pathologists to produce hybrids of important cropping species resistant to several virus diseases. the concepts of mendelian genetics were applied to plant virology by francis oliver holmes, an american scientist who must be considered a pioneer in several fields of modern plant virology. during th ... | 2001 | 11718380 |
| automated identification of filaments in cryoelectron microscopy images. | since the foundation for the three-dimensional image reconstruction of helical objects from electron micrographs was laid more than 30 years ago, there have been sustained developments in specimen preparation, data acquisition, image analysis, and interpretation of results. however, the boxing of filaments in large numbers of images--one of the critical steps toward the reconstruction at high resolution--is still constrained by manual processing even though interactive interfaces have been built ... | 2001 | 11722170 |
| local expression of enzymatically active class i beta-1, 3-glucanase enhances symptoms of tmv infection in tobacco. | mutant tobacco plants deficient for class i beta-1,3-glucanase (glu i) are decreased in their susceptibility to virus infection. this is correlated with delayed virus spread, a reduction in the size exclusion limit of plasmodesmata and increased cell-wall deposition of the beta-1,3-glucan callose. to further investigate a role of glu i during cell-to-cell movement of virus infection, we inserted the glu i coding sequence into tmv for overexpression in infected cells. compared with the size of lo ... | 2001 | 11722778 |
| comparative properties of two peptide-antibody interactions as deduced from epitope delineation. | the linear epitope recognized by three closely related antibodies specific for the e6 oncoprotein of papillomavirus type 16 was delineated by phage display, spot peptide synthesis on cellulose membranes, and kinetic measurements with antigenic variants using a biacore. the same approaches, recently applied to an antibody specific for tobacco mosaic virus protein, led to the clear-cut delineation of a functional epitope comprising four key positions with well defined physico-chemical properties. ... | 2002 | 11730843 |
| dynamic changes in the frequency and architecture of plasmodesmata during the sink-source transition in tobacco leaves. | the sink-source transition in tobacco leaves was studied noninvasively using transgenic plants expressing the green-fluorescent protein (gfp) under control of the arabidopsis thaliana suc2 promoter, and also by imaging transgenic plants that constitutively expressed a tobacco mosaic virus movement protein (mp) fused to gfp (mp-gfp). the sink-source transition was measured on intact leaves and progressed basipetally at rates of up to 600 microns/h. the transition was most rapid on the largest sin ... | 2001 | 11732318 |
| alkaloids from cynanchum komarovii with inhibitory activity against the tobacco mosaic virus. | a pyrroloisoquinoline alkaloid, 2,3-dimethoxy-6-(3-oxo-butyl)-7,9,10,11,11a,12-hexahydrobenzo[f]pyrrolo[1,2-b]isoquinoline (1), whose structure was determined by spectroscopic methods, was isolated from the aerial parts of cynanchum komarovii, together with two known alkaloids, 7-demethoxytylophorine (2) and 7-demethoxytylophorine n-oxide (3). alkaloids 2 and 3 had antiviral activities against tobacco mosaic virus. | 2001 | 11738420 |
| solution structures of potato virus x and narcissus mosaic virus from raman optical activity. | potato virus x (pvx) and narcissus mosaic virus (nmv) were studied using vibrational raman optical activity (roa) in order to obtain new information on the structures of their coat protein subunits. the roa spectra of the two intact virions are very similar to each other and similar to that of tobacco mosaic virus (tmv) studied previously, being dominated by signals characteristic of proteins with helix bundle folds. in particular, pvx and nmv show strong positive roa bands at approximately 1340 ... | 2002 | 11752721 |
| transgenic tobacco plants expressing the potato virus x open reading frame 3 gene develop specific resistance and necrotic ring symptoms after infection with the homologous virus. | tobacco plants were transformed with the open reading frame 3 gene from potato virus x (pvx) coding for the p12 protein. although the transgenic plants exhibited a normal morphological aspect, microscopic examination revealed extensive alterations in leaf tissue structure. after being challenged with pvx, the transgenic plants showed resistance to pvx infection and formation of specific leaf symptoms consisting of concentric rings encircled by necrotic borders. these novel symptoms were accompan ... | 2001 | 11763125 |
| a major quantitative trait locus for resistance to potato leafroll virus is located in a resistance hotspot on potato chromosome xi and is tightly linked to n-gene-like markers. | potato leafroll virus (plrv) causes one of the most widespread and important virus diseases in potato. resistance to plrv is controlled by genetic factors that limit plant infection by viruliferous aphids or virus multiplication and accumulation. quantitative trait locus (qtl) analysis of resistance to virus accumulation revealed one major and two minor qtl. the major qtl, plrv.1, mapped to potato chromosome xi in a resistance hotspot containing several genes for qualitative and quantitative res ... | 2001 | 11768537 |
| activity of nitric oxide is dependent on, but is partially required for function of, salicylic acid in the signaling pathway in tobacco systemic acquired resistance. | when tobacco plants were treated by injection with nitric oxide (no)-releasing compounds, the sizes of lesions caused by tobacco mosaic virus (tmv) on the treated leaves and on upper nontreated leaves were significantly reduced. the reduction in tmv lesion size was caused by no released from the no-releasing compounds; the byproduct formed after release of no from the no-releasing compound noc-18, diethylenetriamine, did not itself alter lesion size. treatment of tobacco plants with inhibitors o ... | 2001 | 11768542 |
| appearance of "beta-like" circular dichroism spectra on protein aggregation that is not accompanied by transition to beta-structure. | cd spectra in the 200 to 250 nm spectral region for small ordered aggregates (trimers-pentamers) of tobacco mosaic virus (tmv) coat protein (cp) and for long virus-like helical aggregates of tmv cp were compared. it was found that small (4s) tmv cp aggregates have a cd spectrum typical of a protein with high alpha-helix content, which agrees well with results of x-ray diffraction studies. but in the long helical aggregates (and in the tmv virions) tmv cp gives "beta-like" cd spectra similar to t ... | 2001 | 11812245 |
| ribosome-inactivating and adenine polynucleotide glycosylase activities in mirabilis jalapa l. tissues. | several tissues of mirabilis jalapa l. (nyctaginaceae) were assayed for inhibition of translation by a rabbit reticulocyte lysate (as a signal of ribosome-inactivating activity) and for adenine dna glycosylase activity, activities that are both due to the presence of a class of enzymes called ribosome-inactivating proteins (rips), currently classified as rrna n-glycosylases (ec ). these activities were highest in seed; intermediate in flower bud, immature seed, sepal + gynoecium, leaf, and root; ... | 2002 | 11825901 |
| salicylic acid has cell-specific effects on tobacco mosaic virus replication and cell-to-cell movement. | tobacco mosaic virus (tmv) and cucumber mosaic virus expressing green fluorescent protein (gfp) were used to probe the effects of salicylic acid (sa) on the cell biology of viral infection. treatment of tobacco with sa restricted tmv.gfp to single-epidermal cell infection sites for at least 6 d post inoculation but did not affect infection sites of cucumber mosaic virus expressing gfp. microinjection experiments, using size-specific dextrans, showed that sa cannot inhibit tmv movement by decreas ... | 2002 | 11842159 |
| the spread of tobacco mosaic virus infection: insights into the cellular mechanism of rna transport. | interactions of plant cells with pathogens or other biotic or abiotic environmental factors can give rise to systemic defense responses that rely upon the cell-to-cell and systemic transport of specific signals. a novel type of systemic signaling was revealed by recent evidence indicating the existence of rna species that travel cell to cell and through the vasculature. the most compelling evidence for intercellular and systemic transport of rna in plants is provided by viroids and viruses that ... | 2002 | 11846035 |
| induction of pepper cdna encoding a lipid transfer protein during the resistance response to tobacco mosaic virus. | pepper (capsicum annuum) plants exhibit hypersensitive response (hr) against infection by many tobamoviruses. a clone encoding a putative nonspecific lipid transfer protein (caltp1) was isolated by differential screening of a cdna library from resistant pepper leaves when inoculated with tobacco mosaic virus (tmv) pathotype p0. the predicted amino acid sequence of caltp1 is highly similar to that of the other plant ltps. southern blot analysis showed that a small gene family of ltp-related seque ... | 2002 | 11855726 |
| an eds1 orthologue is required for n-mediated resistance against tobacco mosaic virus. | in arabidopsis, eds1 is essential for disease resistance conferred by a structural subset of resistance (r) proteins containing a nucleotide-binding site, leucine-rich-repeats and amino-terminal similarity to animal toll and interleukin-1 (so-called tir-nbs-lrr proteins). eds1 is not required by nbs-lrr proteins that possess an amino-terminal coiled-coil motif (cc-nbs-lrr proteins). using virus-induced gene silencing (vigs) of a nicotiana benthaminana eds1 orthologue, we investigated the role of ... | 2002 | 11874570 |
| purification and properties of antiviral proteins from the leaves of bougainvillea xbuttiana. | a non-phytotoxic, resistance inducing, proteinaceous antiviral principle was purified by ammonium sulphate fractionation, ion exchange chromatography and gel filtration from the leaves of bougainvillea xbuttiana. it imparted resistance against tobacco mosaic virus (tmv) and sunnhemp rosette virus (srv) in their respective test hosts viz. nicotiana glutinosa, n. tabacum var. samsun nn, and cyamopsis tetragonoloba, respectively. the purified principle eluted as a single peak upon gel filtration, b ... | 2001 | 11886084 |
| characterization of mutant tobacco mosaic virus coat protein that interferes with virus cell-to-cell movement. | expression of tobacco mosaic virus (tmv) coat protein (cp) in plants confers resistance to infection by tmv and related tobamoviruses. certain mutants of the cp (cp(t42w)) provide much greater levels of resistance than wild-type (wt) cp. in the present work, infection induced by rna transcripts of tmv clones that contain wt cp or mutant cp(t42w) fused to the green fluorescent protein (gfp) (tmv-cp:gfp, tmv-cp(t42w):gfp) and clones harboring tmv movement protein (mp):gfp were followed in nontrans ... | 2002 | 11891326 |
| intramolecular complementing mutations in tobacco mosaic virus movement protein confirm a role for microtubule association in viral rna transport. | the movement protein (mp) of tobacco mosaic virus (tmv) facilitates the cell-to-cell transport of the viral rna genome through plasmodesmata (pd). a previous report described the functional reversion of a dysfunctional mutation in mp (pro81ser) by two additional amino acid substitution mutations (thr104ile and arg167lys). to further explore the mechanism underlying this intramolecular complementation event, the mutations were introduced into a virus derivative expressing the mp as a fusion to gr ... | 2002 | 11907237 |
| induced expression of a temperature-sensitive leucine-rich repeat receptor-like protein kinase gene by hypersensitive cell death and wounding in tobacco plant carrying the n resistance gene. | a gene encoding a receptor-like protein kinase was isolated as the gene induced in the early period of n gene-dependent hypersensitive cell death in tobacco leaves. the kinase domain expressed as a glutathione s-transferase fusion protein was capable of autophosphorylation, indicating that this gene encodes an active protein kinase. a high level of the transcript accumulated before necrotic lesion formation in tobacco mosaic virus (tmv)-inoculated tobacco leaves carrying the n gene but it was lo ... | 2002 | 11917080 |
| the tobacco bzip transcription factor bzi-1 binds to g-box elements in the promoters of phenylpropanoid pathway genes in vitro, but it is not involved in their regulation in vivo. | screening of a tobacco (nicotiana tabacum) cdna library resulted in the isolation of a clone encoding the bzip transcription factor bzi-1. with respect to amino acid sequence, conservation of protein domains, genomic exon-intron structure and expression pattern, bzi-1 is closely related to cprf2, ohp1/2, blz1 and reb, a group of bzip proteins which have been described in a number of dicot and monocot species. bzi-1 exhibits the characteristics of a transcription factor. it binds to g-box and c-b ... | 2002 | 11919711 |
| polymerization of tobacco mosaic virus protein in na pyrophosphate. | | 1972 | 11946622 |
| the cause of irreversible polymerisation of tobacco mosaic virus protein. | | 1972 | 11946740 |
| the effect of tetranitromethane on the activity of anti-tobacco mosaic virus antibodies. | | 1970 | 11947578 |
| the sambucus nigra type-2 ribosome-inactivating protein sna-i' exhibits in planta antiviral activity in transgenic tobacco. | transgenic tobacco (samsun nn) plants transformed with a cdna clone encoding sna-i' from sambucus nigra synthesize, and correctly process and assemble, a fully active type-2 ribosome-inactivating protein. expression of sna-i' under the control of the 35s cauliflower mosaic virus promoter enhances the plant's resistance against infection with tobacco mosaic virus. in contrast to type-1 ribosome-inactivating proteins, the expression of sna-i' does not affect the growth and fertility of the transge ... | 2002 | 11959096 |
| nematic ordering of rigid rods in a gravitational field. | the isotropic-to-nematic transition in an athermal solution of long rigid rods subject to a gravitational (or centrifugal) field is theoretically considered in the onsager approximation. the new feature emerging in the presence of gravity is a concentration gradient that coupled with the nematic ordering. for rodlike molecules this effect becomes noticeable at centrifugal acceleration g approximately 10(3)-10(4) m/s(2), while for biological rodlike objects, such as tobacco mosaic virus, the effe ... | 1999 | 11970103 |
| identification of early-responsive genes associated with the hypersensitive response to tobacco mosaic virus and characterization of a wrky-type transcription factor in tobacco plants. | in order to identify genes that are involved in the defense reaction against pathogen attack, we screened for examples that are regulated during the hypersensitive response (hr) to infection by tobacco mosaic virus (tmv) of tobacco ( nicotiana tabacum cv. xanthi nc) carrying the n gene, which confers resistance to tmv. among seven genes initially identified by fluorescent differential display, one clone was further characterized because its transcripts accumulated rapidly and transiently after t ... | 2002 | 11976958 |
| eukaryotic elongation factor 1a interacts with the upstream pseudoknot domain in the 3' untranslated region of tobacco mosaic virus rna. | the genomic rna of tobacco mosaic virus (tmv), like that of other positive-strand rna viruses, acts as a template for both translation and replication. the highly structured 3' untranslated region (utr) of tmv rnas plays an important role in both processes; it is not polyadenylated but ends with a trna-like structure (tls) preceded by a conserved upstream pseudoknot domain (upd). the tls of tobamoviral rnas can be specifically aminoacylated and, in this state, can interact with eukaryotic elonga ... | 2002 | 11991996 |
| [cleavage activity of ribozymes on a target rna of tobacco mosaic virus in e. coli]. | a target cdna fragment from tmv rna was inserted to a reporter gene cat immediately to the 3' end of the translation initiation codon atg resulting in the formation of a chimeric cat gene in an in vivo transcription and expression vector. the in vivo activities of various ribozymes on the target sequence were observed by determining the changes of the cat activities of the chimeric cat gene expressed in e. coli. the cat activity was reduced by up to 30% when a specific ribozyme rz1, rz1a or rz1b ... | 1998 | 12016955 |
| tobacco rar1, eds1 and npr1/nim1 like genes are required for n-mediated resistance to tobacco mosaic virus. | the tobacco n gene confers resistance to tobacco mosaic virus (tmv) and encodes a toll-interleukin-1 receptor/nucleotide binding site/leucine-rich repeat (tir-nbs-lrr) class protein. we have developed and used a tobacco rattle virus (trv) based virus induced gene silencing (vigs) system to investigate the role of tobacco candidate genes in the n-mediated signalling pathway. to accomplish this we generated transgenic nicotiana benthamiana containing the tobacco n gene. the transgenic lines exhibi ... | 2002 | 12028572 |
| silencing of a gene encoding a protein component of the oxygen-evolving complex of photosystem ii enhances virus replication in plants. | it has been suggested that, in addition to viral proteins, host proteins are involved in rna virus replication. in this study the rna helicase domain of the tobacco mosaic virus (tmv) replicase proteins was used as bait in the yeast two-hybrid system to identify tobacco proteins with a putative role in tmv replication. two host proteins were characterized. one protein (designated #3) belongs to a protein family of atpases associated with various activities (aaa), while the second host protein (d ... | 2002 | 12033790 |
| downregulation of a pathogen-responsive tobacco udp-glc:phenylpropanoid glucosyltransferase reduces scopoletin glucoside accumulation, enhances oxidative stress, and weakens virus resistance. | plant udp-glc:phenylpropanoid glucosyltransferases (ugts) catalyze the transfer of glc from udp-glc to numerous substrates and regulate the activity of compounds that play important roles in plant defense against pathogens. we previously characterized two tobacco salicylic acid- and pathogen-inducible ugts (togts) that act very efficiently on the hydroxycoumarin scopoletin and on hydroxycinnamic acids. to identify the physiological roles of these ugts in plant defense, we generated togt-depleted ... | 2002 | 12034899 |
| expression and purification of a neuropeptide nocistatin using two related plant viral vectors. | both odontoglossum ringspot virus (orsv) and tobacco mosaic virus (tmv) were investigated as expression viral vectors for the expression of a neuropeptide nocistatin. chimeras of orsv and tmv were constructed by fusion of 17 amino acids of mouse nocistatin (mnst) to the c-terminal of the coat protein (cp) gene via a factor xa cleavage linker to yield orsv-mnst and tmv-mnst. expression of the mnst peptide was demonstrated by immuno-transmission electron microscopy, western blot, mass spectrometry ... | 2002 | 12036585 |
| improvement of the movement and host range properties of a plant virus vector through dna shuffling. | virus expression vectors based on the tobacco mosaic virus (tmv) genome are powerful tools for foreign gene expression in plants. however, the inclusion of increased genetic load in the form of foreign genes limits the speed of systemic plant invasion and host range of these vectors due to reduced replication and movement efficiencies. to improve these properties of tmv vectors, the gene encoding the 30-kda movement protein was subjected to mutagenesis and dna shuffling. a vector that expresses ... | 2002 | 12047633 |
| expression of recombinant trichosanthin, a ribosome-inactivating protein, in transgenic tobacco. | trichosanthin (tcs) is an antiviral plant defense protein, classified as a type-i ribosome-inactivating protein, found in the root tuber and leaves of the medicinal plant trichosanthes kirilowii. it is processed from a larger precursor protein, containing a 23 amino acid amino (n)-terminal sequence (pre sequence) and a 19 amino acid carboxy (c)-terminal extension (pro sequence). various constructs of the tcs gene were expressed in transgenic tobacco plants to determine the effects of the amino- ... | 2002 | 12052684 |