| selection of prosomes and prosomal rna by immobilized viral rnas. | viral messengers were used to select and purify prosomes and prosomal rna from subribosomal fractions of hela cells and mouse erythroblasts. adenovirus mrna immobilized on oligo(dt)-cellulose and tobacco mosaic virus rna (tmv) sedimenting in sucrose gradients associated strongly with prosomes at high salt conditions forming intermolecular rna-rna hybrids between prosomal rna and viral rna. hybrid selection of small cytoplasmic rnas with immobilized tmv-rna revealed a rna species migrating at the ... | 1990 | 2401359 |
| immune induction by a protein antigen and by a peptide segment of the protein. | the immune induction by a protein (the tobacco mosaic virus protein-tmvp) was compared to the immune induction by the free, non-conjugated eicosa tryptic peptide fragment of the protein (tryptic peptide 8 representing residues 93-112 of the protein). the results demonstrated that like tmvp, peptide 8 was immunogenic in a/j mice. tmvp and peptide 8 do not cross react on the t cell level. however, immunization with tmvp or with peptide 8 induces antibodies which react with both tmvp and peptide 8. ... | 1985 | 2416198 |
| anti-sense regions in satellite rna of cucumber mosaic virus form stable complexes with the viral coat protein gene. | the interaction in vitro of the rna of the q-strain of cucumber mosaic virus (cmv) with its satellite rna (sat-rna) has been studied. in hybridisation reactions containing 30% formamide at 45 degrees, sat-rna binds to cmv rna 3 and 4 but not to cmv rna 1 and 2 or rna from tobacco mosaic virus and alfalfa mosaic virus. the viral coat protein gene present in rna 3 and 4 contains the site of binding but this region does not contain complementary sequences of any significant length to the sat-rna se ... | 1986 | 2422629 |
| influence of local structure on the location of antigenic determinants in tobacco mosaic virus protein. | early work on protein antigenicity led to the common belief that proteins possess a finite number of antigenic determinants located in accessible regions of the molecule's surface. this view is now changing. as a result of extensive studies, seven continuous epitopes have been located on tobacco mosaic virus (tmv) protein by measuring the antigenic activity of short peptides with anti-protein antibodies. the structure of the viral protein has been refined in cambridge, enabling the strasbourg wo ... | 1986 | 2426056 |
| antigenic requirements for t-cell activation: reconstitution of a functional antigen from an inactive peptide portion of an antigen conjugated to protein carriers. | the structural features of an antigenic peptide required for t-cell activation were examined by a novel approach: an active antigen was constructed from an inactive peptide portion of the original antigen by conjugating it to various proteins. an eicosapeptide, peptide 8, representing residues 103-112 of the tobacco mosaic virus protein (tmvp), was utilized as the model antigen for these studies. while peptide 8 was able to stimulate, in vitro, t-cells from peptide 8 primed mice, synthetic pepti ... | 1986 | 2427934 |
| tobacco mosaic virus coat protein and the large subunit of the host protein ribulose-1,5-biphosphate carboxylase share a common antigenic determinant. | an immunological relationship was detected between the coat protein of the common (u1) strain of tobacco mosaic virus (tmv) and the large subunit of the ubiquitous co2-fixing host enzyme, ribulose-1,5-biphosphate carboxylase (rubisco). when assayed by western immunoblotting or indirect elisa, polyclonal antisera to tmv coat protein and to rubisco reacted with both antigens. in addition, a monoclonal antibody specific for the c-terminal antigenic determinant of tmv coat protein reacted with rubis ... | 1986 | 2430360 |
| characterization of epitopes shared by alpha-melanocyte-stimulating hormone (alpha-msh) and the 150-kd neurofilament protein (nf150): relationship to neurotrophic sequences. | immunoblot techniques and immunohistochemistry have been used to investigate epitopes shared by alpha-melanocyte-stimulating hormone (alpha-msh) and the 150-kd neurofilament protein (nf150). three anti-alpha-msh antisera (namely 31h2t, 4394, and m5) from a total of 12 sera were found to react with nf150. the three crossreacting sera are different in their binding properties to peptide fragments related to alpha-msh, suggesting that at least two distinct epitopes are shared by nf150 and alpha-msh ... | 1986 | 2432275 |
| conformational specificity of monoclonal antibodies used in the diagnosis of tomato mosaic virus. | ten monoclonal antibodies (mcabs) were raised to the tobamovirus, tomato mosaic virus (tomv). seven of the mcabs reacted with tomv only when tested in an elisa format, involving antibody-coated plates, which preserved the quaternary conformation of the viral protein. two mcabs which reacted with tomv only in an elisa using virus-coated plates recognized an antigenic determinant present only on the disassembled form of the viral coat protein. one mcab reacted with both the assembled and dissociat ... | 1987 | 2437887 |
| specific inhibition of tobacco mosaic virus protein and single-stranded rna synthesis by arabinofuranosyladenine. | 9-beta-d-arabinofuranosyladenine (ara a) was shown to inhibit a specific step of tobacco mosaic virus (tmv) multiplication. the time course of the ara a-sensitive function occurred 'late' coinciding with the period of viral rna and protein synthesis. when treatment began after viral rna synthesis was established, 1.0 mm ara a inhibited viral single-stranded rna and viral protein synthesis, but not viral double-stranded rna synthesis. viral double-stranded rna synthesis was inhibited totally only ... | 1986 | 2438250 |
| studies on the suppression of the immune response to a defined protein epitope by anti-idiotypic antibodies. | we have previously reported that c3h.sw (csw) and a/j mice immunized with the tobacco mosaic virus protein (tmvp) produce antibodies to a decapeptide epitope corresponding to amino acid residues 103-112 of the protein. in the c3h.sw (csw) strain, the antibodies to the decapeptide contain major crossreactive idiotope, c10-idx, which is found on a csw-derived monoclonal antidecapeptide antibody, designated as c10. the in vivo administration of anti-c10 antibodies suppresses the response to the dec ... | 1987 | 2444348 |
| immunochemical studies of tobacco mosaic virus--vii. use of comparative surface accessibility of residues in antigenically related viruses for delineating epitopes recognized by monoclonal antibodies. | the binding properties of 18 monoclonal antibodies (mabs) directed against the tobacco mosaic virus (tmv) coat protein were studied with five related tobamoviruses and seven mutant viruses, as well as with the dissociated coat proteins of these variants. ten of the antibodies bound to both tmv and tmv protein, but these were able to discriminate between different mutants only when whole virus particles were compared in the immunoassay. three mabs reacted with tmv but not with dissociated viral s ... | 1987 | 2448610 |
| visualization by electron microscopy of the location of tobacco mosaic virus epitopes reacting with monoclonal antibodies in enzyme immunoassay. | the binding of monoclonal antibodies obtained after immunization with tobacco mosaic protein was analyzed by electron microscopy. a method was developed for visualizing the viral antigen reacting in different elisa procedures. it was found that the use of a ph 9.6 buffer during the coating of elisa plates led to the dissociation of virions into subunits which bound preferentially to the solid phase. mabs that reacted with both virions and subunits in elisa were found to bind to one of the two ex ... | 1988 | 2448951 |
| replication of chimeric tobacco mosaic viruses which carry heterologous combinations of replicase genes and 3' noncoding regions. | three tobacco mosaic virus (tmv)-l (tomato strain)-derived chimeras, designated ol1, lg11, or lk31, were constructed by replacing the 3' noncoding region with the corresponding sequence of tmv-om (common strain), cucumber green mottle mosaic virus (cgmmv), or tmv-cc (cowpea strain), respectively. the genomic rnas of tmv-l, -om, and cgmmv carry histidine-accepting trna-like structures at their 3' termini, while the genome of tmv-cc accepts valine. the three chimeric viruses were able to multiply ... | 1988 | 2452515 |
| selective recovery of foreign gene transcripts as virus-like particles in tmv-infected transgenic tobaccos. | a short origin-of-assembly sequence (oas) located in the 30kda movement protein gene, about 1.0kb from the 3'-end of the common strain of tobacco mosaic virus (tmv) rna, nucleates encapsidation of the 6395-nucleotide-long genome by tmv coat protein in vitro, and presumably also in vivo. single-stranded rnas containing a foreign reporter gene sequence and the tmv oas at their 5' - and 3' -ends, respectively, can be synthesized in vitro from recombinant sp6-transcription plasmids and will assemble ... | 1988 | 2453837 |
| studies on the clonality of the response to an epitope of a protein antigen. randomness of activation of epitope-recognizing clones and the development of clonal dominance. | syngeneic mice immunized with tobacco mosaic virus protein (tmvp) can differ with respect to their ability to produce antibodies that bind a decapeptide epitope representing residues 103 to 112 of tmvp, and with respect to the fine specificity of the decapeptide binding antibodies as determined by their ability to bind several synthetic analogues of the decapeptide. to elucidate the mechanism responsible for the differences between the syngeneic animals in their ability to make anti-decapeptide ... | 1988 | 2454264 |
| limitations of different elisa procedures for localizing epitopes in viral coat protein subunits. | the reactivity of monoclonal antibodies (mcabs) to the coat protein of tobacco mosaic virus (tmvp) with the isolated coat protein, disks, virions and a number of antigenic variants of tmv was tested in eight different elisa procedures. although certain mcabs, when used as detecting antibody in the liquid phase, did not react with some of these antigens, they were able to bind to them when used as the capturing antibody on the solid phase. this finding was attributed to the ability of the trappin ... | 1989 | 2473721 |
| the concept and operational definition of protein epitopes. | the antigenic determinants or epitopes of a protein correspond to those parts of the molecule that are specifically recognized by the binding sites or paratopes of certain immunoglobulin molecules. epitopes are thus relational entities that require complementary paratopes for their operational recognition. some authors consider that the concept of epitope necessarily involves the two properties of antigenic reactivity (ability to bind to a paratope) and immunogenicity (ability to induce an immun ... | 1989 | 2474169 |
| protection against tobacco mosaic virus in transgenic plants that express tobacco mosaic virus antisense rna. | transgenic tobacco plants that express rna sequences complementary to the tobacco mosaic virus (tmv) coat protein (cp) coding sequence with or without the trna-like structure at the 3' end of the tmv rna were produced. progeny of self-pollinated plants were challenged with tmv to determine their resistance to infection. plants that expressed rna sequences complementary to the cp coding region and the 3' untranslated region, including the trna-like sequences, were protected from infection by tmv ... | 1989 | 2476807 |
| in vivo-induced suppression of t cell proliferation: the relationship between the specificity of induction and control. | we have previously shown that sc immunization of c57bl/10 (h-2b) mice with the tobacco mosaic virus protein (tmvp) or with its tryptic peptide number 8, representing residues 93-112 of tmvp, induces t cells which proliferate in vitro in response to tmvp and to peptide 8. in contrast, immunization of b10.br (h-2k) mice either with tmvp or with peptide 8 induces t cells which respond in vitro to the homologous but not the heterologous ag. in the present article , we report that in the b10.br (h-2k ... | 1989 | 2478299 |
| pea early browning virus rna1 encodes four polypeptides including a putative zinc-finger protein. | we have determined the complete nucleotide sequence of rna1 of the tobravirus pea early browning virus [pebv] from an overlapping series of cdna clones. the 7073 nucleotide sequence contains four open reading frames [orfs]. the 5' proximal orf encodes a 141k polypeptide, and readthrough of the opal [uga] termination codon of this orf would lead to the synthesis of a second, 201k polypeptide. both of these polypeptides have extensive amino acid homology with the putative replicase proteins of tob ... | 1989 | 2495522 |
| indolinone derivatives as potential antimicrobial agents. | 1-substituted aminomethyl-3-cyclohexylthiosemicarbazone-2-indolinones (i) were tested for their antibacterial activity against bacillus pumilis, bacillus brevis and bacillus megaterium and antifungal activity against aspergillus flavus, aspergillus fumigatus and aspergillus niger. the majority of the compounds were found to exhibit promising antibacterial and antifungal activities. these compounds were also screened for their antiviral action against tobacco mosaic virus in nicotiana glutinosa p ... | 1989 | 2501946 |
| steep gradients of inert substances as supports for precipitin reactions. | precipitin reactions were conducted in the wells of micro titer plates and the light "absorbance" at 405nm plotted as a function of the neg log2 dilutions of the antigens using the titertek multiscan apparatus. the procedure followed was to incorporate antibody in 20% sucrose and to diffuse the mixture into serial two-fold dilutions of antigen overlaid on the sugar-antibody columns in the wells. where the antigen met its antibody in equivalence precipitin bands formed. the bands of precipitates ... | 1989 | 2504668 |
| probable reassortment of genomic elements among elongated rna-containing plant viruses. | the relationships of genome organization among elongated (rod-shaped and filamentous) plant viruses have been analyzed. sequences in coding and noncoding regions of barley stripe mosaic virus (bsmv) rnas 1, 2, and 3 were compared with those of the monopartite rna genomes of potato virus x (pvx), white clover mosaic virus (wclmv), and tobacco mosaic virus, the bipartite genome of tobacco rattle virus (trv), the quadripartite genome of beet necrotic yellow vein virus (bnyvv), and icosahedral trico ... | 1989 | 2504930 |
| detection of beta-1,3-glucanase activity after native polyacrylamide gel electrophoresis: application to tobacco pathogenesis-related proteins. | beta-1,3-glucanase (laminarinase) activity was detected after polyacrylamide gel electrophoresis under native conditions by using laminarin as substrate. following incubation of gels, laminarin was stained with aniline blue. under uv illumination, lysis zones appeared as dark bands against a fluorescent background. as low as 0.001 unit of commercial penicillium laminarinase could be observed after incubating the polyacrylamide gel for 45 min at ph 5.0. extracts of commercial penicillium laminari ... | 1989 | 2506010 |
| constitutive expression of pathogenesis-related proteins pr-1, grp, and pr-s in tobacco has no effect on virus infection. | samsun nn tobacco cells were transformed with chimeric genes for pathogenesis-related (pr) proteins derived from genomic (pr-1a, grp) or cdna (pr-s) clones under the transcriptional control of the cauliflower mosaic virus 35s promoter. regenerated plants were assayed by rna and protein gel blotting, and plants showing high specific expression of the inserted genes were selected for self-pollination and seed formation. inspection of second generation transformants showed that constitutive express ... | 1989 | 2535503 |
| visualizing mrna expression in plant protoplasts: factors influencing efficient mrna uptake and translation. | in this paper we demonstrate that rna sequences present upstream and downstream of a reporter gene coding region play an important role in determining the amount of protein produced from an mrna. a translational enhancer, omega, derived from tobacco mosaic virus, when present at the 5'-end of beta-glucuronidase mrna increased the efficiency of translation 16-fold to 18-fold in electroporated tobacco or carrot protoplasts, and threefold to 11-fold in maize or rice protoplasts. the presence of ome ... | 1989 | 2535505 |
| mutations in the tobacco mosaic virus 30-kd protein gene overcome tm-2 resistance in tomato. | a resistance-breaking strain of tobacco mosaic virus (tmv), ltb1, is able to multiply in tomatoes with the tm-2 gene, unlike its parent strain, l. nucleotide sequence analysis of ltb1 rna revealed two amino acid changes in the 30-kd protein: from cys68 to phe and from glu133 to lys (from l to ltb1). strains with these two changes generated in vitro multiplied in tomatoes with the tm-2 gene and induced essentially the same symptoms as those caused by ltb1. strains with either one of the two chang ... | 1989 | 2535549 |
| effects of ph and ionic strength on precipitation of phytopathogenic viruses by polyethylene glycol. | the effects of ionic strength of the solution (changed by varying nacl concentrations or buffer molarity) on the precipitation with polyethylene glycol (peg) 6000 were studied on phytopathogenic viruses of different morphology: the isometric red clover mottle virus (rcmv), rod-shaped tobacco mosaic virus, flexuous potato virus x (pvx) and bacilliform alfalfa mosaic virus. with increasing nacl concentration or buffer molarity up to a certain level (0.1 mol/l), the efficiency of peg precipitation ... | 1989 | 2565676 |
| the idiotypic characterization of the immune response to a defined epitope of a protein antigen and the specific in vivo suppression of the immune response to this epitope by anti-idiotypic antibodies. | c10, a monoclonal antibody of c3h.sw (csw) origin, binds a decapeptide epitope of the tobacco mosaic virus protein (tmvp) representing residues 103-112 of the protein. in vivo administration of syngeneic anti-idiotypic antibodies to c10 (anti-c10) prior to immunization with tmvp suppressed the expression of antibodies to this decapeptide determinant in csw mice without a significant reduction of the total anti-tmvp titer. the suppression could not be overcome with repeated challenges by antigen ... | 1985 | 2580019 |
| immunochemical studies of tobacco mosaic virus--vi. attempts to localize viral epitopes with monoclonal antibodies. | the specificity of 18 monoclonal antibodies directed to tobacco mosaic virus (tmv) was studied by measuring their ability to bind to viral mutants, to other tobamoviruses, to dissociated viral subunits and to peptide fragments of the viral coat protein. the apparent binding specificity of the antibodies was dependent on the type of enzyme-linked immunosorbent assay used, probably because the antigens were disrupted or denatured when attached to the plastic surface of microtiter wells. the capaci ... | 1985 | 2582247 |
| nucleotide sequences of 5' and 3' non-coding regions of pepper mild mottle virus strain s rna. | the nucleotide sequences of the 5' and 3' non-coding regions of pepper mild mottle virus strain s (pmmv-s) rna were determined; they are more like corresponding sequences of tomato mosaic virus (tomv) rna than those of any other tobamovirus reported so far. the 5' leader contains a 68 nucleotide guanosine-free sequence which differs in several nucleotides from the corresponding sequences in genomic rna of tobacco mosaic virus (tmv) and tomv. the messenger activity of pmmv-s rna in vitro and the ... | 1989 | 2584952 |
| preliminary analysis of crystals of satellite tobacco mosaic virus. | satellite tobacco mosaic virus (stmv), a small t = 1 icosahedral plant virus, has been crystallized in a form suitable for high-resolution x-ray diffraction analysis. the crystals, which diffract to better than 2.5 a resolution, are of space group i222 and have unit cell dimensions of a = 176 a, b = 192 a and c = 205 a. the centers of the virus particles occupy 222 symmetry points in the unit cell and one quarter of the virus particle constitutes the asymmetric unit, which is therefore comprised ... | 1989 | 2585487 |
| assembly of hybrid rnas with tobacco mosaic virus coat protein. evidence for incorporation of disks in 5'-elongation along the major rna tail. | we have shown that during the reassembly of tobacco mosaic virus (tmv) rna, with the coat protein supplied as a "disk preparation", the lengths of rna protected from nuclease are "quantized" with steps which correspond to incorporation of the subunits from either a single or, more commonly, both rings of a disk. this interpretation has been challenged and it was suggested that the pattern was due to special, though unspecified features of the sequence of tmv rna. to test whether the specific seq ... | 1989 | 2585493 |
| decreased levels of tmv coat protein in transgenic tobacco plants at elevated temperatures reduce resistance to tmv infection. | transgenic tobacco plants that accumulate tobacco mosaic virus (tmv) coat protein (cp) are resistant to tmv infection under standard growth conditions. the amount of cp accumulated and the degree of resistance to tmv were found to be temperature dependent. exposure to continuous high temperatures (30-35 degrees) results in a sharp decrease in the amount of cp within 6 hr with no further change for at least 6 days. under these conditions the transgenic plants developed typical systemic disease sy ... | 1989 | 2596028 |
| effect of protein aggregation state on coat protein-mediated protection against tobacco mosaic virus using a transient protoplast assay. | to address the mechanism(s) of protection against tobacco mosaic virus (tmv) infection conferred by expression of the tmv capsid protein (cp) gene in transgenic tobacco plants, a transient protection assay has been developed. introduction of either purified viral cp or virus inactivated by ultraviolet irradiation into tobacco protoplasts induced a transient protection to challenge virus introduced concomitantly or shortly thereafter. the transient protection was characterized and the effects of ... | 1989 | 2596034 |
| tobacco mosaic virus coat protein: an elicitor of the hypersensitive reaction but not required for the development of mosaic symptoms in nicotiana sylvestris. | specific nucleotide changes in the coat protein gene of tobacco mosaic virus (tmv) have been identified as responsible for the induction of the hypersensitive reaction (hr) in nicotiana sylvestris. each of these nucleotide changes resulted in amino acid substitutions in the coat protein. to determine if the altered viral rna or the altered protein acted directly to elicit the hr, the coat protein translational starts were removed from full-length cdna clones of the hr-inducing mutant tmv 25 and ... | 1989 | 2596036 |
| the complete sequence of soybean chlorotic mottle virus dna and the identification of a novel promoter. | the complete nucleotide sequence of an infectious clone of soybean chlorotic mottle virus (soycmv) dna was determined and compared with those of three other caulimoviruses, cauliflower mosaic virus (camv), carnation etched ring virus and figwort mosaic virus. the double-stranded dna genome of soycmv (8,175 bp) contained nine open reading frames (orfs) and one large intergenic region. the primer binding sites, gene organization and size of orfs were similar to those of the other caulimoviruses, e ... | 1989 | 2602148 |
| a translational enhancer derived from tobacco mosaic virus is functionally equivalent to a shine-dalgarno sequence. | when present at the 5' end of mrnas, the untranslated leader sequence (omega) of tobacco mosaic virus rna significantly enhances translation in eukaryotes and prokaryotes. we have tested a deletion derivative of the omega sequence, omega delta 3, for its enhancing ability on gene constructs in which the ribosomal binding site was either present or deleted, in several gram-negative bacterial species including escherichia coli, agrobacterium tumefaciens, xanthomonas campestris pv. vitians, erwinia ... | 1989 | 2643095 |
| use of rabbit fab'-peroxidase conjugates prepared by the maleimide method for detecting plant viruses by elisa. | in contrast to antibodies conjugated to enzyme with glutaraldehyde or by the periodate method, monomeric fab' fragments conjugated to enzyme by means of a maleimide compound are not adversely affected by the conjugation procedure. we used such fab'-enzyme conjugates prepared with antibody to tobacco mosaic virus (tmv), to tmv coat protein and to rabbit igg for the detection of different tobamoviruses by direct and indirect double antibody sandwich enzyme-linked immunosorbent assay (das-elisa). c ... | 1989 | 2668313 |
| are the pr1 proteins of tobacco involved in genetically engineered resistance to tmv? | transgenic tobacco plants constitutively expressing the coat protein (cp) of tobacco mosaic virus (tmv) exhibit enhanced resistance ot tmv (p. powell abel, r. s. nelson, b. de, n. hoffman, s. g. rogers, r. t. fraley, and r. n. beachy, science, 232, 738-743, 1986; r. s. nelson, p. powell abel, and r. n. beachy, virology 158, 128-132, 1987). to determine if this enhanced resistance might be mediated through the pr1 family of pathogenesis-related (pr) proteins, their synthesis was examined. in tran ... | 1989 | 2705308 |
| association of viral 126 kda protein-containing x-bodies with nuclei in mosaic-diseased tobacco leaves. | during the development of systemic mosaic symptoms in tobacco mosaic virus (tmv)-infected tobacco, the viral non-structural 126-kda-protein was present among the chromatin-associated proteins in fractionated leaf homogenates [van telgen hj et al. (1984) virology 143: 612-616]. using an antiserum raised against a fusion protein of beta-galactosidase and part of the 126-kda-protein of tmv, this viral protein was detected by immunoelectron microscopy in x-bodies in infected tissue. no labelling of ... | 1989 | 2705877 |
| nucleotide sequence and translation of satellite tobacco mosaic virus rna. | satellite tobacco mosaic virus (stmv) is a plant virus with a 17-nm icosahedral particle encapsidating a 0.3 x 10(6) mr ssrna genome that depends on tobamoviruses for its replication. the complete nucleotide sequence of stmv rna deduced in the experiments described here was 1059 nucleotides in length. the efficiency of labeling viral rna with [gamma-32p]atp using t4 polynucleotide kinase was not affected by treatment with tobacco acid pyrophosphatase and/or bacterial alkaline phosphatase, indica ... | 1989 | 2718378 |
| decreased accuracy of protein synthesis in extracts from aging human diploid fibroblasts. | the accuracy of protein synthesis has been measured in extracts from human diploid fibroblasts of different ages. extracts were supplied with purified mrna for the coat protein of the cowpea variant of tobacco mosaic virus (cctmv), which lacks codons for cysteine and methionine. the presence of 35s-cysteine in cctmv coat protein synthesized during translation reactions therefore represents translational error. translation reactions were performed with extracts from young fibroblasts (less than 5 ... | 1989 | 2721600 |
| anomalous electrophoretic behavior of the major potato virus x rna translation product. | the major potato virus x (pvs) rna translation product migrates in laemmli's electrophoresis system as a 210 kda polypeptide ('p210'). if a tris-phosphate-sds buffer system is used instead of a tris-glycine-sds one, the mobility of p210 is higher than that of the largest tmv rna translation product, the 183 kda protein. it is suggested that anomalous electrophoretic behavior of the largest pvx polypeptide during sds-electrophoresis is due to its primary structure, namely to the presence of hydro ... | 1989 | 2723020 |
| nucleotide sequence of barley stripe mosaic virus rna alpha: rna alpha encodes a single polypeptide with homology to corresponding proteins from other viruses. | the complete nucleotide sequence of rna alpha from the type strain of barley stripe mosaic virus has been determined. the rna is 3768 nucleotides long and contains a single open reading frame which codes for a polypeptide of 1139 amino acids (mw 129,634). the open reading frame is flanked by a 5'-terminal sequence of 91 nucleotides and a 3'-nontranslated region composed of a short poly(a) tract followed by a 238-nucleotide trna-like structure. the amino acid sequence of the polypeptide (alpha a) ... | 1989 | 2728343 |
| genetic heterogeneity of the rna genome population of the plant virus u5-tmv. | the genetic heterogeneity in a population of the u5 strain of tobacco mosaic virus (u5-tmv) was studied. the t1 fingerprint characterizing a cloned population did not vary after a new cloning step in the local lesion host nicotiana tabacum xanthi-nc, nor during four series of 20 passages in the systemic host n. tabacum samsum. no heterogeneity was observed among 10 clones derived from the cloned populations, while 1 of 18 clones derived from a 20-fold passaged population differed from the rest i ... | 1989 | 2728345 |
| use of monoclonal antibodies in the purification of an inhibitor of virus replication by affinity chromatography. | mouse monoclonal antibodies (mabs) were prepared to an inhibitor of virus replication (ivr), released from protoplasts or leaf tissue of hypersensitive tobacco plants infected with tobacco mosaic virus. the mabs were highly specific for ivr and reduced its antiviral activity. using these mabs in affinity chromatography enabled the recovery of purified ivr. sds-page of the immunoaffinity-purified ivr gave a single mr 23k band. immunoblots of ivr from extracts of protoplast or leaf tissue also rev ... | 1989 | 2732715 |
| [use of a cell-free protein synthesizing system from cells of ascites carcinoma krebs-2 for rna translation of plant viruses]. | cell-free translation in krebs-2 extracts was optimized for rnas of two plant viruses; potato virus x (pvx, potexvirus), and tobacco mosaic virus (tmv, tobamovirus). pvx and tmv rnas programmed synthesis of similar sets of polypeptides in both the krebs-2 extracts and the rabbit reticulocyte lysates, major virus-specific products being the same in molecular weight in both in vitro systems. pvx structural protein (p29) was absent among polypeptides synthesized in the krebs-2 system but was readil ... | 1989 | 2739641 |
| birefringence of macromolecules. wiener's theory revisited, with applications to dna and tobacco mosaic virus. | we summarize wiener's theory of the dielectric constant of heterogeneous systems and extend its application to suspensions of particles with corrugated surfaces and interstitial solvent. we retain a simple geometrical shape for the particles and account specifically for the solvent associated with the particles. we calculate the birefringence of the rodshaped tobacco mosaic virus (tmv) particle and of dna and find excellent agreement between our numerical results and experimental values from the ... | 1989 | 2752088 |
| translational capacity of sheep oocytes microinjected with messenger rna. | sheep oocytes were microinjected with tobacco mosaic virus rna (tmv-rna) and isotopically labelled with l-[35s]methionine. total incorporation of labelled methionine was similar in tmv-rna-injected and in carrier-injected control oocytes, whether injections were performed during the period of high protein synthesis at maturation or during the period of reduced synthesis at a time equivalent to the mid-cleavage transition (48 h after germinal vesicle breakdown). varying the amount of tmv-rna inje ... | 1989 | 2754648 |
| uv laser induced rna-protein crosslinks and rna chain breaks in tobacco mosaic virus rna in situ. | the efficiency of rna-protein crosslink and rna chain break formation under nanosecond or picosecond uv-laser pulse irradiation of tobacco mosaic virus was determined. it was found that on high-intensity uv-laser irradiation the quantum yields of both reactions increase considerably as compared to the usual (low-intensity) uv-irradiation. the rna-protein crosslink quantum yield was found to be 1.8 x 10(-5) and 1.2 x 10(-4) and that of rna chain breaks 1.7 x 10(-4) and 8.9 x 10(-4) for nanosecond ... | 1989 | 2755995 |
| spurious cross-reactions between plant viruses and monoclonal antibodies can be overcome by saturating elisa plates with milk proteins. | it has been claimed recently [dietzgen (1986) arch virol 91: 163-173] that a series of monoclonal antibodies (mabs) produced against the nepovirus, arabis mosaic virus (armv) cross-reacted with the tobamovirus, tobacco mosaic virus (tmv). in the present report, this alleged cross-reactivity was re-examined by two elisa procedures using mabs produced against each of the two viruses. it was found that when highly concentrated preparations of mabs were used, all antibodies reacted in a nonspecific ... | 1989 | 2764726 |
| visualization of protein-nucleic acid interactions in a virus. refined structure of intact tobacco mosaic virus at 2.9 a resolution by x-ray fiber diffraction. | the structure of tobacco mosaic virus (tmv) has been determined by fiber diffraction methods at 2.9 a resolution, and refined by restrained least-squares to an r-factor of 0.096. protein-nucleic acid interactions are clearly visible. the final model contains all of the non-hydrogen atoms of the rna and the protein, 71 water molecules, and two calcium-binding sites. viral disassembly is driven by electrostatic repulsions between the charges in two carboxyl-carboxylate pairs and a phosphate-carbox ... | 1989 | 2769760 |
| a tobacco mosaic virus-hybrid expresses and loses an added gene. | an additional open reading frame from the chloramphenicol acetyltransferase (cat) gene was fused behind a tobacco mosaic virus (tmv) subgenomic rna promoter and inserted into different positions in the complete tmv genome to examine how much this viral genome can be altered with continued replication. one hybrid virus, cat-cp, with the insertion between the 30k and coat protein genes, replicated efficiently, produced an additional subgenomic rna and cat activity, and assembled into 350-nm virion ... | 1989 | 2773319 |
| sequence of cowpea chlorotic mottle virus rnas 2 and 3 and evidence of a recombination event during bromovirus evolution. | the genomic sequence of cowpea chlorotic mottle virus (ccmv) was completed by sequencing biologically active cdna clones of ccmv rna2 (2774 bases) and rna3 (2173 bases). while only the central core of the encoded 94-kda ccmv 2a protein contains features conserved among known and putative rna replication proteins from many viruses, both flanking regions of ccmv 2a show substantial similarity to the corresponding protein of the related brome mosaic virus (bmv). the 3a proteins of ccmv and bmv, imp ... | 1989 | 2773323 |
| evidence that nucleocapsid disassembly and a later step in virus replication are inhibited in transgenic tobacco protoplasts expressing tmv coat protein. | tobacco mosaic virus (tmv)-like pseudovirus particles containing mrna for escherichia coli beta-glucuronidase (gus) were electroporated into mesophyll protoplasts from control or tmv coat protein (cp)-transgenic tobacco (nicotiana tabacum cv. xanthi). gus-particles were expressed 100-fold less efficiently in cp-transformed than in control protoplasts whereas unencapsidated gus mrna was expressed only 2.8-fold less efficiently. lower transient expression of packaged gus mrna is probably due to in ... | 1989 | 2773325 |
| rapid, random evolution of the genetic structure of replicating tobacco mosaic virus populations. | the effects of temperature and type of host on the evolution of variants in replicating populations of tobacco mosaic virus (tmv) originating from an in vitro rna transcript of a cdna clone were studied. the phenotypic markers measured were temperature-sensitive (ts) replication and induction of necrotic local lesions (nl) on nicotiana sylvestris. the proportions of ts variants were about the same under all conditions tested, but changes in temperature or host had strong effects on proportions o ... | 1989 | 2777537 |
| synchrotron x-ray scattering study of chromatin condensation induced by monovalent salt: analysis of the small-angle scattering data. | small-angle x-ray scattering experiments were carried out on rat thymus chromatin in "native" and "h1-depleted" states at various nacl concentrations using synchrotron radiation. from the analysis of cross-sectional guinier plots, the radius of gyration of the cross section (rc) and the mass per unit length (mc) of native chromatin were evaluated. in the absence of nacl, the cross section of chromatin filament has a radius of gyration of 3.44 nm, suggesting the structure corresponding to the "10 ... | 1989 | 2777743 |
| [identification of a peptide of the membrane protein of tobacco mosaic virus, cross-linked with intraviral rna under the effect of uv-radiation]. | as reported previously, uv-irradiation induces crosslinking between tobacco mosaic virus (tmv) coat protein molecules and intraviral rna nucleotides. we have irradiated [3h]-uridine labeled tmv and isolated tmv coat protein subunits with the attached nucleotide label. these tmv protein subunits were hydrolyzed with trypsin. the tryptic peptides were separated by high-performance liquid chromatography and [3h]-labeled peptides were identified. the uv-irradiation of tmv was found to result in cros ... | 1989 | 2811905 |
| mutational analysis of the coat protein gene of tobacco mosaic virus in relation to hypersensitive response in tobacco plants with the n' gene. | tomato strain l of tobacco mosaic virus (tmv-l) induces a hypersensitive response (necrotic local lesions) on tobacco plants with the n' gene. a factor responsible for induction of the hypersensitive response has been mapped to the coat protein gene. we have constructed several mutants which have insertions or deletions in the coat protein gene. frame-shift mutants which cause premature termination of translation of the coat protein caused no necrotic local lesions on n' plants. mutants which re ... | 1989 | 2815580 |
| disease response to tobacco mosaic virus in transgenic tobacco plants that constitutively express the pathogenesis-related pr1b gene. | correlation of the temporal and spacial pattern of induction of the pathogenesis-related (pr) genes pr1a, pr1b, and pr1c with viral infections in certain tobacco cultivars has implicated pr proteins in viral disease resistance. to test whether the pr1 proteins of tobacco are involved in viral resistance, transgenic nicotiana tabacum plants were constructed which constitutively express the pr1b gene. this protein was secreted from cells of transgenic plants and accumulated in the extracellular sp ... | 1989 | 2815592 |
| on the inhibition of plant virus multiplication by ribavirin. | the inhibition of the replication of potato virus x (pvx), belladonna mottle virus, tobacco mosaic virus, potato virus y (pvy), and tobacco necrosis virus by ribavirin and pyrazofurin is described with emphasis on the inhibition of pvx by ribavirin. ribavirin inhibits an early step of pvx replication. the inhibition is reversed to different degrees by all ribo- and deoxyribonucleosides, most strongly by thymidine. in tobacco leaves, nucleosides compete with ribavirin for phosphorylation to monop ... | 1987 | 2821895 |
| characterisation of the 5'-leader sequence of tobacco mosaic virus rna as a general enhancer of translation in vitro. | uncapped messenger rnas (mrnas) encoding calf preprochymosin, chicken prelysozyme, or escherichia coli beta-glucuronidase (gus) were synthesized in vitro, with or without a 5'-terminal 67-nucleotide sequence (omega') derived from the untranslated 5'-leader (omega) of tobacco mosaic virus (tmv) rna. messenger rnas were translated in vitro, in messenger-dependent systems derived from rabbit reticulocytes (mdl), wheat-germ (wg) or e. coli (ec). the omega' sequence enhanced expression of each mrna i ... | 1987 | 2832252 |
| expression of tobacco mosaic virus rna in transgenic plants. | tobacco mosaic virus (tmv) is a message-sense, single-stranded rna virus that infects many solanaceae plants. a full-length cdna copy of tmv genomic rna was constructed and introduced into the genomic dna of tobacco plants using a disarmed ti plasmid vector. transformed plants showed typical symptoms of tmv infection, and their leaves contained infectious tmv particles. this is the first example of the expression of rna virus genomic rnas in plants. | 1988 | 2835637 |
| tobacco mosaic virus particles contain ubiquitinated coat protein subunits. | virions of tobacco mosaic virus (tmv) are composed of a single strand of rna, encapsidated in about 2130 copies of a coat protein of mw 17,500. asselin and zaitlin [virology 91, 173-181 (1978)] demonstrated that virion preparations also contained small amounts of a second protein of mw 26,500, which they termed "h protein." h protein, detectable to an average frequency of one per virion, was thought to be a protein of host origin. subsequent studies [collmer, vogt, and zaitlin, virology 126, 429 ... | 1988 | 2838968 |
| studies on the mechanism of translational enhancement by the 5'-leader sequence of tobacco mosaic virus rna. | translation of foreign mrnas is enhanced by a cis-acting derivative (omega') of the 5'-leader sequence (omega) of tobacco mosaic virus rna (vulgare strain). to explain this effect we have conducted several experiments in vitro. 1. the presence of various 5'-terminal sequences, including omega', did not significantly increase the half-lives of chloramphenicol acetyltransferase (cat) or neomycin phosphotransferase (nptii) mrnas in wheat-germ extract. also, a long leader sequence, unrelated to omeg ... | 1988 | 2841127 |
| hybrid brome mosaic virus rnas express and are packaged in tobacco mosaic virus coat protein in vivo. | brome mosaic virus (bmv) is an icosahedral virus with a tripartite rna genome which infects monocotyledonous plants, while the cowpea or legume strain of tobacco mosaic virus (cctmv) is a rod-shaped virus with a single component rna genome which infects dicotyledonous plants. to examine the potential for exchanging entire genes between rna viruses, biologically active cdna clones were used to replace the natural coat gene of bmv rna3 with the coat gene and encapsidation origin of cctmv. in proto ... | 1988 | 2847411 |
| three dimensional structure of bacterial pili. | crystallographic and associated biochemical and structural studies are in progress on the fiber-forming pilin proteins of the gonococcal pilus. preparative scale purification procedures have been developed for the gonococcal pilin protein, which appear generally applicable to bacterial pilins. for three gonococcal pilin protein strains, we have obtained both reassembled pilus fibers and three-dimensional crystals. one needle-shaped crystal form of gonococcal c30 pilin diffracts beyond 3 a resolu ... | 1987 | 2897188 |
| understanding the structure and antigenicity of gonococcal pili. | pili--filamentous protein structures found on the cell surface of many infectious gram-negative bacteria--often are virulence factors that mediate adherence to host epithelial cells. the pilus, a major surface antigen of the gonococcus, is formed by the specific association of thousands of repeating identical protein subunits (pilin). structural studies of the pilin protein and the pilus fiber may aid the rational design of a peptide-based vaccine by providing information on the antigenic surfac ... | 1988 | 2903537 |
| virus-ribosome complexes from cell-free translation systems supplemented with cowpea chlorotic mottle virus particles. | when particles of cowpea chlorotic mottle virus (ccmv) were added to cell-free extracts from wheat germ, the encapsidated viral genome was translated into polypeptides similar to the translation products specified by unencapsidated viral rna (as shown before by m.j. brisco, r. hull, and t.m.a. wilson, 1986, virology 148, 210-217). the rate of protein synthesis observed upon addition of virus particles was much slower than that of extracted rna and the quantity of protein formed was only 10% of t ... | 1989 | 2909987 |
| selective inhibition of photosystem ii in spinach by tobacco mosaic virus: an effect of the viral coat protein. | leaves of spinacia oleracea inoculated with tobacco mosaic virus (tmv) strain pv230 develop mild chlorotic and mosaic symptoms of infection. thylakoid membranes isolated from these infected leaves showed a reduced fv/fm ratio for chlorophyll fluorescence kinetics, at 25 degrees c. the photosystem ii (ps ii)-mediated electron-transport rate was inhibited 50%, whereas ps i activity was unaffected by virus infection. protein analysis indicated that tmv coat protein was associated with thylakoids, i ... | 1989 | 2924924 |
| visualization of alpha-helices in tobacco mosaic virus by cryo-electron microscopy. | we have used tobacco mosaic virus (tmv) as a test specimen, in order to develop techniques for the analysis of high-resolution structural detail in electron micrographs of biological assemblies with helical symmetry. it has previously been shown that internal details of protein structure can be visualized by processing electron micrographs of unstained specimens of extended two-dimensional crystalline arrays. however, the techniques should in principle be applicable to other periodic specimens, ... | 1989 | 2926805 |
| a neurospora crassa heat-shocked cell lysate translates homologous and heterologous messenger rna efficiently, without preference for heat shock messages. | cell-free protein synthesis systems were prepared from normally-grown (n-lysate) and heat-shocked (hs-lysate) neurospora crassa mycelium. although both lysates translated homologous mrna, the hs-lysate was more active, yielding a higher incorporation of [35s]-methionine into hot tca-insoluble material and a vastly superior protein synthesis profile. the optimal temperature for translation by both lysates was 21 degrees c; the hs-lysate did not translate heat-shock mrna preferentially at any temp ... | 1988 | 2969781 |
| a virus-inducible tobacco gene encoding a glycine-rich protein shares putative regulatory elements with the ribulose bisphosphate carboxylase small subunit gene. | cdna to an mrna that is strongly induced in samsun nn tobacco after tobacco mosaic virus (tmv) infection or salicylic acid treatment was used to probe a genomic blot and to screen a genomic library. the mrna corresponds to a family of approximately eight genes, four of which were cloned. the sequence of the genes and flanking dna in two clones was determined. one gene was found to contain an intron of 555 bp; s1-nuclease mapping studies indicated that this gene is expressed. the other gene is in ... | 1988 | 2979908 |
| site-specific cleavage of tobacco mosaic virus rna: a study of factors influencing the cleavage. | dna oligomer directed ribonuclease h (rnase h) methodology is applied to specifically cleave tobacco mosaic virus (tmv) rna. using a synthetic dna oligomer p(dt8)dcdc, complementary to a region from nucleotide 5545 to nucleotide 5554 at the 3' end of tmv rna, we have cleaved the rna at the site of polynucleotides complementary to the dna oligomer. factors such as secondary structure of the rna, concentrations of dna oligomer, rnase h and magnesium ions in the reaction mixture, and time of incuba ... | 1985 | 2990647 |
| studies of protein-nucleic acid interactions using model crystals. | for the mutual recognition between protein and nucleic acid, specific interactions between the components of both polymers should be properly combined in a fitting scheme of secondary or tertiary structures. we call these combinations elementary interactions between protein and nucleic acid. the interactions were investigated using the model crystals that contain side chains of amino acid and a nucleic acid base. taking c, t, u, a, and g as base and hydroxyl, carboxyl, carbamoyl, imidazolyl, phe ... | 1988 | 3077238 |
| interactions between dna and coat protein in the structure and assembly of filamentous bacteriophage fd. | bacteriophage fd is a class i filamentous virus (others are m13 and f1) that comprises a circular, single-stranded dna molecule enclosed in a cylindrical protein sheath to form a flexible particle approximately 890 nm long and 7 nm in diameter. the viral dna contains 6,408 nucleotides incorporating 10 genes, and the protein sheath is composed of about 2,700 major coat protein subunits in a shingled helical array, the symmetry of which is defined by a fivefold rotational axis combined with a twof ... | 1987 | 3106834 |
| purified scrapie prions resist inactivation by procedures that hydrolyze, modify, or shear nucleic acids. | prions were purified from scrapie-infected hamster brains and incubated for 24 hr at 65 degrees with 2 mm zn2+ or 5 mm mg2+; no loss of infectivity was observed. bacteriophage m13, tobacco mosaic virus (tmv), potato virus x, and potato spindle tuber viroid were all inactivated by divalent metal ions under these conditions. prions also resisted inactivation by prolonged digestions with dnase i, rnases a and t1, and micrococcal nuclease. prions were resistant to psoralen photoadduct formation usin ... | 1987 | 3114950 |
| selective encapsidation of cat gene transcripts in tmv-infected transgenic tobacco inhibits cat synthesis. | young tobacco seedlings (f1-progeny), transformed to express chloramphenicol acetyltransferase (cat) mrna with or without a 3'-proximal copy of the origin-of-assembly sequence (oas) from tobacco mosaic virus (tmv) rna (residues 5118-5550), were inoculated with tmv. after 21 days, virus symptoms were observed and systemic tmv infections were confirmed by western blotting for viral coat protein and by electron microscopy of leaf saps. cat activities were measured in extracts of leaf discs taken be ... | 1988 | 3165573 |
| the ribosomal fraction mediates the translational enhancement associated with the 5'-leader of tobacco mosaic virus. | the omega sequence at the 5'-terminus of tobacco mosaic virus (tmv) rna acts as a translational enhancer. the differential in omega-associated translational enhancement between the in vitro translation system derived from wheat germ (wg) and that from rabbit reticulocytes (mdl) was exploited to identify that lysate component which was responsible for a lysate's characteristic response to omega. using fractionated mdl and wg lysates, which were reconstituted in various combinations, the high salt ... | 1988 | 3166519 |
| resistance to tmv in transgenic plants results from interference with an early event in infection. | constitutive expression of the tobacco mosaic virus (tmv) coat protein (cp) gene in transgenic tobacco plants results in inhibition of disease symptom development following inoculation with tmv. evidence is presented here that this protection is also observed in leaf mesophyll protoplasts isolated from these plants. protoplasts were resistant to infection by tmv at concentrations of 10 microgram/ml to 1 mg/ml when introduced by either electroporation or polyethylene glycol-mediated inoculation. ... | 1988 | 3176344 |
| subcellular localization of tobacco mosaic virus minus strand rna in infected protoplasts. | radioactive rna probes were prepared which specifically hybridize with sequences complementary to 5' and 3' regions of tobacco mosaic virus (tmv) rna. these probes were used in northern hybridization to locate tmv-rna minus strands in the subcellular fractions of infected tobacco protoplasts. when the protoplasts were lysed with triton x-100, full-length minus strands were present in the cytoplasmic but not in the nuclear fraction. with mechanically broken protoplasts, the crude nuclear fraction ... | 1988 | 3188395 |
| sequence and structure at the genome 3' end of the u2-strain of tobacco mosaic virus, a histidine-accepting tobamovirus. | the primary sequence of the 3' noncoding region of u2-tmv rna was determined. a structural model was proposed based on chemical and enzymatic structure mapping as well as on analyses of nuclease protection by aminoacyl-trna-synthetase. the model agrees with those proposed for tmv "vulgare" rna and confirms their general validity for the tobamoviruses. the rna appears to have a trna-like, l-shaped structure at the 3' terminus, linked to a quasi-continuous double-helical stalk, with five pseudokno ... | 1988 | 3188396 |
| interviral homologies of the 30k proteins of tobamoviruses. | the 30k protein of tobacco mosaic virus was recently confirmed to be involved in cell-to-cell movement of the virus. to characterize common structural features of the 30k protein, the nucleotide sequence of the 30k protein gene of cucumber green mottle mosaic virus (cgmmv, a member of the tobamoviruses) rna has been determined. the cgmmv 30k protein is composed of 264 amino acids with a calculated molecular weight of 28,800. comparisons among the 30k proteins of tobamoviruses show that the 30k p ... | 1988 | 3201760 |
| structure and function of disk aggregates of the coat protein of tobacco mosaic virus. | experiments have been carried out on the coat protein of tobacco mosaic virus (tmvp) to test for the occurrence of the previously postulated rna-induced direct switching, during in vitro assembly of tobacco mosaic virus (tmv), of the subunit packing from the cylindrical bilayer disk to the virus helical arrangement. no evidence was found for such rna-induced switching and no evidence for the direct participation of the bilayer disk in either the nucleation or elongation phases of the in vitro vi ... | 1988 | 3207689 |
| the tobacco mosaic virus assembly origin rna. functional characteristics defined by directed mutagenesis. | the in vitro reassembly of tobacco mosaic virus (tmv) begins with the specific recognition by the viral coat protein disk aggregate of an internal tmv rna sequence, known as the assembly origin (oa). this rna sequence contains a putative stem-loop structure (loop 1), believed to be the target for disk binding in assembly initiation, which has the characteristic sequence aagaagucg exposed as a single strand at its apex. we show that a 75-base rna sequence encompassing loop 1 is sufficient to dire ... | 1988 | 3210225 |
| temperature dependence of the structure of aggregates of tobacco mosaic virus protein at ph 7.2. static synchrotron small-angle x-ray scattering. | the small-angle x-ray scattering (saxs) method using a synchrotron radiation source was applied to the study of the self-aggregation process of tobacco mosaic virus protein (tmvp) at a concentration of 5.0 or 12.0 mg ml-1 in 50 mm or 100 mm-phosphate buffer (ionic strengths approx. 0.1 and 0.2, respectively) at ph 7.2 in the temperature region of 4.8 to 25.0 degrees c. this paper presents the results of static measurements of saxs. sedimentation velocity experiments were performed simultaneously ... | 1988 | 3216388 |
| time-resolved solution x-ray scattering of tobacco mosaic virus coat protein: kinetics and structure of intermediates. | the kinetics of assembly and disassembly of tobacco mosaic virus coat protein (tmvp) following temperature jumps have been studied by small-angle x-ray scattering and turbidimetry. the structures of the principal aggregates of tmvp oligomers (a protein), intermediate size (helix i) and large size helical rods (helix ii), have been characterized by their average radii of gyration of thickness, cross section, and shape obtained from the corresponding regimes of the small-angle scattering pattern. ... | 1988 | 3242597 |
| [mannan sulfates--inducers of plant resistance to viral infection]. | mannan sulphates (ms) synthesized on the basis of extracellular linear mannan (lm) of rhodotorula rubra induce resistance of immune-580 tobacco and thornapple (datura stramonium) to tobacco mosaic virus (tmv). the resistance is manifested in a decrease in the number and/or size of viral local lesions (ll) in ms-treated (mg/ml) leaf halves. the reduction in the ll size does not seem to be due to the direct inhibition of tmv multiplication by the polysaccharide as the virus accumulation in the tis ... | 1988 | 3247692 |
| in vitro transcription and translational efficiency of chimeric sp6 messenger rnas devoid of 5' vector nucleotides. | a plasmid containing the bacteriophage sp6 promoter, designated phsto, permits in vitro transcription of rnas devoid of vector-derived nucleotides. this vector has been characterized for relative transcriptional activity using constructs which alter the conserved nucleotides extending beyond the sp6 transcriptional initiation site. sp6 polymerase efficiently transcribes cdna inserts which contain a guanosine (g) nucleotide at position +1 relative to the sp6 promoter; however, inserts with an ade ... | 1988 | 3260027 |
| structural features of an antigen required for cellular interactions and for t cell activation in a mhc-restricted response. | the protein ag, tobacco mosaic virus protein, (tmvp) and its tryptic peptide number 8 (residues 93-112 of the protein) exhibit cross-reactivity on the t cell level in some strains of mice (e.g., c3h.sw, c57bl/10); these strains are termed cross-reactive (cr). in other strains such as a/j or b10.br, no cross-reactivity is exhibited; these strains are termed non-cross-reactive (ncr). genetic experiments indicated that the cross-reactivity is dominant and that it is mapped to the i-a or i-e region ... | 1988 | 3260252 |
| hyperactivity of donor b cells after neonatal induction of lymphoid chimerism in mice. | balb/c mice made chimaeric by neonatal injection of semi-allogeneic (a/j x balb/c)f1 hybrid spleen cells develop anti-dna and rheumatoid factor-like antibodies in the context of hypergammaglobulinaemia with marked elevation of igg1 and ige serum levels. chimaeric mice also display increased levels of antibodies to different haptens and to tobacco mosaic virus (tmv). the allotypic marker of the a/j strain is present on anti-dna and anti-hapten antibodies. in addition, spleen cells of chimaeric mi ... | 1988 | 3260841 |
| cooperative thermal denaturation of the assembly origin region of tmv rna. | the assembly origin (ao) region of the tobacco mosaic virus rna melts in an usually narrow (2.5 degrees c) temperature range. in an 0.01 m phosphate buffer the melting temperature of ao was found to be 41.5 degrees c. this value corresponds to the regions with the most stable secondary/tertiary structure of the whole tmv rna molecule. it is assumed that the ao region has a specific tertiary structure, which is maintained by the long-range interactions as well as by interactions of the pseudoknot ... | 1987 | 3271460 |
| mutational analysis of the tobacco mosaic virus 5'-leader for altered ability to enhance translation. | mutational analysis of the 5'-untranslated leader sequence (omega) of tobacco mosaic virus (tmv) was carried out to determine those sequences necessary for the translational enhancement associated with omega. five deletion mutants, a single base substitution, and a 25 base replacement mutant were tested for alterations in omega's ability to enhance expression of beta-glucuronidase (gus) mrna in tobacco mesophyll protoplasts and escherichia coli or chloramphenicol acetyltransferase (cat) mrna in ... | 1988 | 3278300 |
| isolation and characterization of cdna clones encoding pathogenesis-related proteins from tobacco mosaic virus infected tobacco plants. | infection of the tobacco cultivar samsun nn by tobacco mosaic virus (tmv) results in a hypersensitive response. during this defense reaction several host encoded proteins, known as pathogenesis-related proteins (pr-proteins), are induced. poly(a)+ rna from tmv infected tobacco plants was used to construct a cdna library. thirty two cdna clones were isolated and after digestion with different restriction endonucleases, twenty clones were found to code for pr-1a, six clones for pr-1b, and four clo ... | 1987 | 3295779 |
| synthesis and localization of pathogenesis-related proteins in tobacco. | the pr1 family of pathogenesis-related proteins from tobacco (nicotiana tabacum l.) leaves is induced by a variety of pathogenic and chemical agents and is associated with resistance to tobacco mosaic virus. the majority of the pr1 proteins did not copurify with mesophyll protoplasts (the major cell type of the leaf) isolated from tobacco mosaic virus-infected n. tabacum cv. xanthi-nc leaves. however, these isolated protoplasts were capable of synthesizing and selectively secreting the pr1 prote ... | 1987 | 3299048 |
| [tobacco mosaic virus vector]. | | 1987 | 3314117 |
| assembly of collagen fibrils de novo by cleavage of the type i pc-collagen with procollagen c-proteinase. assay of critical concentration demonstrates that collagen self-assembly is a classical example of an entropy-driven process. | type i procollagen was purified from the medium of cultured human fibroblasts incubated with 14c-labeled amino acids, the nh2-terminal propeptides were cleaved with procollagen n-proteinase, and the resulting pc-collagen was isolated by gel filtration chromatography. pc-collagen did not assemble into fibrils or large aggregates even at concentrations of 0.5 mg.ml-1 at 34 degrees c in a physiological buffer. however, cleavage of pc-collagen to collagen with purified c-proteinase (hojima, y., (198 ... | 1987 | 3316206 |
| immunogold localization of the intracellular sites of structural and nonstructural tobacco mosaic virus proteins. | antibodies raised against the 126k nonstructural protein (replicase) encoded by tobacco mosaic virus (tmv) rna or the viral coat protein have been used to localize these proteins within virus-infected tobacco leaf cells by an immunogold labeling technique. a protocol is given for low-temperature fixation to facilitate immunogold labeling. in cells of tmv-infected leaf tissue, the 126k protein immunogold label was found almost exclusively in "viroplasms" in the cytoplasm and in pockets of virus p ... | 1987 | 3318095 |
| effect of actinomycin d on tobacco mosaic virus (tmv) accumulation in isolated tobacco protoplasts under varying light conditions. | the effect on tobacco mosaic virus (tmv) accumulation of actinomycin d (amd) introduced shortly after inoculation into isolated tobacco protoplasts under varying light conditions was examined. the emission spectrum of the light source contained lines in the visible range and in the ultraviolet band (300-400 nm). amd absorbed light in the visible (400-500 nm) and in the uv (200-400 nm) ranges. amd substantially inhibited tmv multiplication in the light, and also when the protoplasts were incubate ... | 1988 | 3347998 |