PMID(sorted descending)
analysis of sindbis virus promoter recognition in vivo, using novel vectors with two subgenomic mrna promoters.four types of sindbis virus vectors, each carrying two promoters for subgenomic mrna synthesis, were designed to measure relative promoter strengths and to survey potential contextual effects on promoter strengths. one of the promoters in each vector was used as the reference promoter, while the other was the one being tested. we used these vectors to measure the relative strengths of four promoters: the minimal promoter, an extended sequence believed to have full promoter activity, and two muta ...19912016769
antiidiotypic antibodies as probes for the sindbis virus receptor.rabbit polyclonal antiidiotypic antibodies were made to mouse monoclonal antibodies that neutralize the infectivity of sindbis virus. one of the antiidiotypic antisera obtained has properties characteristic of an antireceptor antiserum. it binds to the surface of chicken cells as shown by immunofluorescence and partially blocks virus binding to these cells as determined by binding of radiolabeled virus or by a plaque reduction assay. it also immunoprecipitates a protein with a molecular weight o ...19912014644
complementation between sindbis viral rnas produces infectious particles with a bipartite genome.sindbis virus, the type member of the alpha-viruses, is an enveloped virus containing a nonsegmented positive-strand rna genome. we show that the nonstructural and the structural genes can function to produce infectious virus particles when they are expressed on two different rna segments. the nonstructural genes are translated from an rna in which the structural genes have been replaced by the chloramphenicol acetyltransferase gene [xiong, c., levis, r., shen, p., schlesinger, s., rice, c. m. & ...19912014249
mechanism of altered sindbis virus neurovirulence associated with a single-amino-acid change in the e2 glycoprotein.the mechanism by which amino acid changes in the e1 and e2 surface glycoproteins of sindbis virus affect neurovirulence is unknown. we have studied two recombinant viruses which differ in virulence. one (te) contains gly and the other (tes) contains arg at position 172 in e2. te causes more rapid death than tes in newborn mice. both viruses replicate similarly in nonneuronal cells, but te replicates more rapidly in the brains of newborn mice and in neuroblastoma cells. te also induces earlier vi ...19911995953
defective transport of sindbis virus glycoproteins in end4 mutant chinese hamster ovary cells.mutant v.24.1, a temperature-sensitive derivative of chinese hamster ovary cells, defines the end4 complementation group of mutants selected for resistance to protein toxins and has defective lysosomes at the restrictive temperature (p. a. colbaugh, m. stookey, and r. k. draper, j. cell biol. 108:2211-2219, 1989). we have investigated the biosynthesis of sindbis virus envelope glycoproteins in v.24.1 cells. when the cells were infected at the restrictive temperature, the envelope glycoproteins e ...19911995947
behavior of a transitional tubulovesicular compartment at the cis side of the golgi apparatus in in vivo fusion studies of mammalian cells.we have investigated the behavior in in vivo cell fusion experiments of a transitional compartment lying between the endoplasmic reticulum and golgi apparatus to determine if the compartment, as recognized by the antibody g1/93, might congregate in a similar manner to golgi apparatus [w. c. ho et al. (1990) eur. j. cell biol. 52, 315-327]. the distributions of the transitional tubulovesicular compartment, endoplasmic reticulum, and golgi apparatus in hela cells were assessed by immunofluorescent ...19911995296
vector roles of fennoscandian mosquitoes attracted to mammals, birds and frogs.1. mosquitoes were sampled with five suction traps, from may to october 1983, at a forest site in south-central sweden. 2. twenty-three species of mosquitoes were identified among the total of 3108 females collected: 4% of them in an unbaited trap, 3% in a trap baited with two frogs, 24% with a guinea-pig, 28% with a hen and 40% in a trap baited with a rabbit. 3. the dominant species of culicidae trapped were 39% aedes communis (de geer), 21% ae. cinereus meigen, 14% coquillettidia richiardii (f ...19901983455
enhancement of the interferon-induced double-stranded rna-dependent protein kinase activity by sindbis virus infection and heat-shock extracts of fl cells that were infected with sindbis virus or treated with heat-shock stress, dsrna-dependent phosphorylation of 77k protein was markedly increased. the 77k phosphoprotein was indistinguishable from the autophosphorylated and activated form of interferon (ifn)-induced dsrna-dependent protein kinase (pk-i) by two-dimensional gel electrophoresis, and was immunologically related to p68 (galabru, j. and hovanessian, a., j. biol. chem. 262, 15538 (1987], the hela cell counterpart o ...19901963922
the nucleotide sequence and genome organization of the rna-1 segment in two bromoviruses: broad bean mottle virus and cowpea chlorotic mottle virus.the complete nucleotide sequences of the rna-1 segments in broad bean mottle virus (bbmv) and cowpea chlorotic mottle virus (ccmv) were determined. bbmv rna-1 consists of 3158 nucleotides and ccmv rna-1 has 3171 nucleotides. both bbmv and ccmv rna-1 are capped at the 5' end but, unlike in other tricornaviruses, bbmv rna-1 initiates with an a residue. both bbmv and ccmv rna-1 are monocistronic encoding for highly homologous 1a proteins of 966 and 958 amino acids, respectively. the highest homolog ...19911962437
structure of sindbis virus core protein reveals a chymotrypsin-like serine proteinase and the organization of the virion.sindbis virus consists of a nucleocapsid core surrounded by a lipid membrane through which penetrate 80 glycoprotein trimers. the structure of the core protein comprising the coat surrounding the genomic rna has been determined. the polypeptide fold from residue 114 to residue 264 is homologous to that of chymotrypsin-like serine proteinases with catalytic residues his 141, asp 163 and ser 215 of the core protein positioned as in other serine proteinases. the c-terminal tryptophan remains in the ...19911944569
sindbis virus rna polymerase is degraded by the n-end rule pathway.upon infection of animal cells by sindbis virus, four nonstructural (ns) proteins, termed nsp1-4 in order from 5' to 3' in the genome, are produced by posttranslational cleavage of a polyprotein. nsp4 is believed to function as the viral rna polymerase and is short-lived in infected cells. we show here that nsp4 produced in reticulocyte lysates is degraded by the n-end rule pathway, one ubiquitin-dependent proteolytic pathway. when the n-terminal residue of nsp4 is changed by mutagenesis, the me ...19911924357
specific binding of host cell proteins to the 3'-terminal stem-loop structure of rubella virus negative-strand the 5' end of the rubella virus genomic rna, there are sequences that can form a potentially stable stem-loop (sl) structure. the complementary negative-strand equivalent of the 5'-end sl structure of positive-strand rubella virus rna [5' (+) sl structure] is thought to serve as a promoter for the initiation of positive-strand synthesis. we screened the negative-strand equivalent of the 5' (+) sl structure (64 nucleotides) and the adjacent region of the negative-strand rna for their ability t ...19911920622
x-ray solution scattering of sindbis virus. changes in conformation induced at low ph.alphaviruses, like many enveloped animal viruses, enter the cell by fusing with the cell membrane. this fusion occurs only in coated vesicles at a low ph. by using x-ray solution scattering of highly purified virus particles we have gained direct evidence that a drop in ph does not alter the structure of the virus core but does cause a significant change in the structure of the virus envelope. thus these experiments give direct evidence to support the hypothesis that a reduction in ph causes a c ...19911920415
a highly purified factor viii:c concentrate prepared from cryoprecipitate by ion-exchange chromatography.a new ion-exchange chromatographic procedure has been developed to produce a highly purified factor viii (fviii) concentrate from plasma cryoprecipitate. solubilized cryoprecipitate, after adsorption on aluminium hydroxide and cold precipitation, was treated with 0.3% tri(n-butyl)phosphate and 1% tween 80 at 25 degrees c for at least 8 h to inactivate lipid-enveloped viruses. the fraction was then loaded onto a column packed with deae-fractogel tsk 650 m and chromatographed. most proteins and tn ...19911905084
infection initiated by the rna pregenome of a dna virus.we describe experiments demonstrating that after transfection into permissive cells, the rna pregenome of an avian hepadnavirus, the duck hepatitis b virus, is infectious. using a sindbis virus expression vector, we showed that cytoplasmic synthesis of the pregenome resulted in hepadnaviral dna synthesis. moreover, complete infectious virus was produced from cells transfected with hepadnaviral pregenomic rna. we conclude that the pregenome of hepadnaviruses can express all the proteins required ...19911895392
inhibition of influenza virus formation by a peptide that corresponds to sequences in the cytoplasmic domain of the hemagglutinin.a decapeptide with a sequence corresponding to the cytoplasmic domain of the influenza virus hemagglutinin inhibited the release of virus particles and infectious virions when added to infected cultured cells for a 2-hr period during a one-cycle growth. inhibition was dose-dependent in the range of 50 to 250 micrograms/ml. the peptide did not affect formation of intracellular virus-specific proteins or assembly of nucleocapsids and did not inhibit replication of two unrelated enveloped rna virus ...19911853575
a mutant cho-k1 strain with resistance to pseudomonas exotoxin a and alphaviruses fails to cleave sindbis virus glycoprotein pe2.rpe.40, a mutant cho-k1 strain selected for resistance to pseudomonas exotoxin a, is defective in the production of infectious alphaviruses, although viruses are taken in and processed normally (j. m. moehring and t. j. moehring, infect. immun. 41:998-1009, 1983). to determine the cause of this defect, the synthesis of sindbis virus proteins was examined. rpe.40 cells produced and glycosylated structural glycoprotein precursors pe2 and immature e1 normally. mature e1 was formed, but pe2 was not ...19911850015
stress-induced neuroinvasiveness of a neurovirulent noninvasive sindbis virus in cold or isolation subjected mice.effects of cold or isolation stress on brain penetration by the neurovirulent noninvasive sindbis virus strain (svn) were studied in mice. svn injected intracerebrally (i.c.) causes acute encephalitis and kills adult mice but is unable to invade the brain and kill when injected intraperitoneally (i.p.). mice inoculated i.p. with svn were exposed to cold stress or were singly housed. both stress patterns induced svn encephalitis and death in 42% (cold) and 37% (isolation) of the tested mice. no d ...19911849216
proteolytic processing of the sindbis virus membrane protein precursor pe2 is nonessential for growth in vertebrate cells but is required for efficient growth in invertebrate cells.we have shown previously that processing of the sindbis virus envelope protein precursor pe2 to envelope protein e2 is not required for virus maturation in cultured vertebrate fibroblast cells and that unprocessed pe2 can be incorporated into infectious virus in place of e2 (j. f. presley and d. t. brown, j. virol. 63:1975-1980, 1989; d. l. russell, j. m. dalrymple, and r. e. johnston, j. virol. 63:1619-1629, 1989). to better understand the role of this processing event in the invertebrate vecto ...19911848310
solubilization and immunoprecipitation of alphavirus replication complexes.alphavirus replication complexes that are located in the mitochondrial fraction of infected cells which pellets at 15,000 x g (p15 fraction) were used for the in vitro synthesis of viral 49s genome rna, subgenomic 26s mrna, and replicative intermediates (ris). comparison of the polymerase activity in p15 fractions from sindbis virus (sin)- and semliki forest virus (sfv)-infected cells indicated that both had similar kinetics of viral rna synthesis in vitro but the sfv fraction was twice as activ ...19911847467
protein-protein interactions in an alphavirus membrane.using homobifunctional chemical cross-linkers with various span distances, we have determined the near-neighbor associations and planar organization of the e1 and e2 envelope glycoproteins which compose the icosahedral surface of sindbis virus. we have found that e1-e2 heterodimers, which form the virus protomeric units, exist in two conformationally distinct forms, reflecting their nonequivalent positions in the icosahedron. three of these heterodimers form the trimeric morphologic units (capso ...19911847448
rescue of sindbis virus-specific rna replication and transcription by using a vaccinia virus recombinant.a heterologous system expressing functional sindbis virus nonstructural proteins (nsps) has several possible uses for studying sindbis virus-specific rna replication and transcription in vivo and in vitro. of the many possible approaches, vaccinia virus offers an attractive transient expression system given that sindbis virus replication can occur in cells which have been previously infected by vaccinia virus. in this report, a vaccinia virus recombinant (called vsinns), which contains the cdna ...19911834861
expression of sindbis virus nsp1 and methyltransferase activity in escherichia coli.we have constructed two plasmids, psr5-42 and psr5-toto, which under lac control expressed the svlm21 and the svtoto forms, respectively, of the sindbis virus nonstructural protein, nsp1. the induced protein, which was the major protein made following induction with iptg, had an apparent molecular weight of 60,000 and an amino terminal sequence in agreement with that expected for nsp1. following induction with iptg, cells carrying psr5-42 (which contains the svlm21 gene sequence) generated much ...19911831311
mutations that confer resistance to mycophenolic acid and ribavirin on sindbis virus map to the nonstructural protein nsp1.svmpa, a mutant of sindbis virus derived by serial passage on aedes albopictus mosquito cells maintained after infection in the presence of mycophenolic acid (mpa), is resistant not only to mpa but also to ribavirin. both of these compounds inhibit the synthesis of gmp and thereby reduce the level of gtp. we had suggested earlier that svmpa had become resistant to mpa because it coded for an altered rna guanylyltransferase enzyme with an increased affinity for gtp, enabling it to replicate in ce ...19911826574
sindbis virus nsp1 functions in negative-strand rna synthesis.a mutation at nucleotide 1101 of sindbis virus ts11 nsp1 caused temperature-sensitive negative-strand synthesis and suppressed the 24r phenotype, which is caused by a mutation in nsp4. nonstructural proteins synthesized and accumulated by ts11 at 40 degrees c did not cause the reactivation of negative-strand synthesis upon return to 30 degrees c and did not prevent the formation of new replication complexes at 30 degrees c.19911824787
effect of polyions on the early events of sindbis virus infection of vero clarify the role of electrostatic interactions in the binding of sindbis virus (snv) to cell membrane receptors, we investigated the effect of different polyions on the initial steps of infection of vero cells by the virus. several polyanions (mucin, heparin, polygalacturonic acid) and polycations (polylysine, protamine, polybrene) were able to reduce the replication of snv when present in the viral adsorption period, whereas others (chondroitin sulfate, polymyxin b sulfate, histone) were dev ...19911759905
the mass of the sindbis virus nucleocapsid suggests it has t = 4 icosahedral symmetry.the mass of the nucleocapsid of the alphavirus sindbis was determined by scanning transmission electron microscopy. the nucleocapsid was found to have an average mass of 10.54 x 10(6) da with the largest percentage of particles showing a mass of 10.7 to 10.9 x 10(6) da. these data predict that the nucleocapsid contains 240 copies of protein and is a t = 4 icosahedron.19921736536
cellular proteins bind to the 3' end of sindbis virus minus-strand rna.forty-four nucleotides at the 5' terminus of the genomic rna of sindbis virus can form a stable stem-loop structure and have been shown previously to be important for viral replication. the structure formed by the complement of this sequence at the 3' end of the minus-strand rna has been proposed to be a promoter for rna replication and as such might be bound in a specific fashion by proteins of either cellular or viral origin. short oligonucleotide probes (either 62 or 132 nucleotides) represen ...19921731089
inhibitor of interferon-induced double-stranded rna-dependent protein kinase and its relevance to alteration of cellular protein kinase activity level in response to external fl cells, interferon (ifn)-induced dsrna-dependent protein kinase (pk-i) was found to be present in a form complexed with a potent inhibitor of its dsrna-dependent activation. the inhibitor was readily dissociated from pk-i by deae-cellulose chromatography to yield a dsrna-responsive pk-i. the inhibitor was also dissociated easily from pk-i by gel filtration through sephacryl s-200. the apparent molecular mass of the inhibitor as estimated by gel filtration was more than 160 kilodaltons. acti ...19911725551
use of a lambda gt11 expression library to localize a neutralizing antibody-binding site in glycoprotein e2 of sindbis virus.the sindbis virus envelope contains two species of integral membrane glycoproteins, e1 and e2. these proteins form heterodimers, and three dimeric units assemble to form spikes incorporated into the viral surface which play an important role in the specific attachment of sindbis virus to host cells. to map the neutralization epitopes on the surface of the virus, we constructed a lambda gt11 expression library with cdna inserts 100 to 300 nucleotides long obtained from randomly primed synthesis o ...19911719239
identification of antigenically important domains in the glycoproteins of sindbis virus by analysis of antibody escape study important epitopes on glycoprotein e2 of sindbis virus, eight variants selected to be singly or multiply resistant to six neutralizing monoclonal antibodies reactive against e2, as well as four revertants which had regained sensitivity to neutralization, were sequenced throughout the e2 region. to study antigenic determinants in glycoprotein e1, four variants selected for resistance to a neutralizing monoclonal antibody reactive with e1 were sequenced throughout the e2 and e1 regions. a ...19911714515
the cytoplasmic domain of alphavirus e2 glycoprotein contains a short linear recognition signal required for viral budding.intracellular alphavirus nucleocapsids express a binding site for the cytoplasmic domain of the viral e2 spike glycoprotein. this binding site is recognized by the anti-idiotype monoclonal antibody, f13. the monoclonal anti-anti-idiotype antibody, raised against f13 and designated 3g10, recognizes the carboxy-terminal eight residues of the e2 cytoplasmic domain in semliki forest virus (sfv), identifying this as the signal for nucleocapsid interaction. f13 binding to cells infected with sfv or a ...19911714373
the three-dimensional structure of frozen-hydrated nudaurelia capensis beta virus, a t = 4 insect virus.the three-dimensional structure of nudaurelia capensis beta virus (n beta v) was reconstructed to 3.2-nm resolution from images of frozen-hydrated virions. the distinctly icosahedral capsid (approximately 40-nm diameter) contains 240 copies of a single 61-kda protein subunit arranged with t = 4 lattice symmetry. the outer surface of unstained virions compares remarkably well with that previously observed in negatively stained specimens. inspection of the density map, volume estimates, and model ...01712620
selection of brain choline acetyltransferase synthetic peptides.choline acetyltransferase (chat) of pig brain is a 640 amino acid enzyme. the sequence has recently been published (berrard et al., 1988). we identified potentially antigenic epitopes on porcine chat by primary and secondary structure analysis. we used 12 structural parameters derived from the amino acid sequence, especially surface antigenicity, internal repetitions and protease cleavage site clusters and superposed gliding averages for the complete chat protein. four peptides from 13 to 21 ami ...19901707146
in vitro protein synthesis. 19911706461
a conformational change in sindbis virus glycoproteins e1 and e2 is detected at the plasma membrane as a consequence of early virus-cell interaction.a conformational change in the structure of sindbis (sb) virus was detected after virion attachment to baby hamster kidney cells but before internalization. the alteration was manifested as increased virion binding of certain glycoprotein e1 and e2 monoclonal antibodies (mabs) that recognized transitional epitopes. these epitopes were inaccessible to mab on native virions but became accessible to their cognate mabs in the early stages of infection. transit of virions through a low-ph compartment ...19901695253
studies on the role of linear epitopes in neutralization of using three synthetic peptides (16-19 amino acids in length) representing different regions of glycoproteins e1 (peptide 3) and e2 (peptides 1 and 2) of sindbis and semliki forest virus and isolated glycoprotein fractions of both viruses in reduced and non-reduced form, the role of linear epitopes for the neutralization was investigated. the reaction patterns of sera induced by immunization with these antigens indicate that conformational epitopes do play the major role in neutralization of a ...19901694615
growth restriction of negative-strand-rna viruses in a rat 3y1 cell line.a rat fibroblast cell line, 3y1 is nonpermissive for infection by several negative-strand-rna viruses including influenza virus a, sendai virus, newcastle disease virus and vesicular stomatitis virus (vsv), but not refractory to that of a positive-strand-rna virus, sindbis virus. to elucidate the mechanism of the restricted viral growth, we compared the replication pattern of vsv in 3y1 cells and in baby hamster kidney cells, which are fully permissive for those viruses. the results indicated th ...19901691814
pathogenesis of encephalitis induced in newborn mice by virulent and avirulent strains of sindbis virus.strains of sindbis virus differ in their virulence for mice of different ages; this variation is related in large part to variations in the amino acid compositions of e1 and e2, the surface glycoproteins. the comparative pathogenesis of sindbis virus strains which are virulent or avirulent for newborn mice has not been previously examined. we have studied the diseases caused by a virulent wild-type strain, ar339, and two less virulent laboratory strains, toto1101 and hrsp (hr small plaque). afte ...19901691310
different pathogenicity of encephalitic togaviruses in organotypic cultures of spinal cord slices.the pathogenicity of two encephalitic togaviruses, sindbis virus (sv), an alphavirus, and west nile virus (wnv), a flavivirus, was studied in organotypic cultures of fetal mouse spinal cord slices grown in roller tubes. after about 3 weeks in vitro, during which time the cultures became abundantly myelinated, they were infected either by 5 x 10(5) pfu sv or by 5 x 10(6) pfu wnv per culture. the viruses caused different patterns of cytopathogenicity: sv induced severe cytotoxicity in all glia cel ...19901691307
isolation of brain parenchymal lymphocytes for flow cytometric analysis. application to acute viral encephalitis.a strategy for the isolation of mononuclear cells from the brain parenchyma of mice with ongoing central nervous system (cns) inflammation has been developed in order to permit flow cytometric (fcm) analysis of these cell populations. sindbis virus (sv) encephalitis in mice is characterized morphologically by an infiltration of mononuclear cells into both brain parenchyma and cerebrospinal fluid (csf). perfused brain tissue from infected animals is collected, homogenized, and subjected to a mild ...19911675228
structure of the ockelbo virus genome and its relationship to other sindbis viruses.ockelbo virus was first isolated in 1982 in sweden. it is the causal agent of disease in humans characterized by arthritis, rash, and fever and is antigenically very closely related to sindbis virus. we have determined the nucleotide and translated amino acid sequences of the prototype ockelbo virus isolate (82-5) to determine the relatedness of ockelbo virus to sindbis virus at the genomic level and clarify the taxonomic position of ockelbo virus within the alphavirus genus. the numbers of nucl ...19911673813
infectious rna transcripts from ross river virus cdna clones and the construction and characterization of defined chimeras with sindbis virus.we have constructed a full-length cdna clone of the virulent t48 strain of ross river virus, a member of the alphavirus genus. infectious rna can be transcribed from this clone using sp6 or t7 rna polymerase. the rescued virus has properties indistinguishable from those of the t48 strain of ross river virus. we have used this clone, together with a full-length cdna clone of sindbis virus, to construct chimeric plasmids in which the 5' and the 3' nontranslated regions of the sindbis and ross rive ...19911673812
ecological distribution of chikungunya haemagglutination inhibition antibodies in human and domestic animals in nigeria.a serological survey to detect presence of antibodies to chikungunya virus in 477 human sera randomly sampled from four ecological zones of nigeria was carried out employing a haemagglutination inhibition (hi) test. similarly 220 animal sera collected mostly from the northern parts of nigeria were screened for hi antibody to chikungunya virus. of the 477 human sera tested a total of 68 or 14.3% were found to possess chikungunya hi antibodies made up of 10% in swampy forest, 20% in the rain fores ...19911667829
screening of medicinal plants from yunnan province in southwest china for antiviral an ethnopharmacological screening of medicinal plants used in yunnan province of china, ethanol extracts from 31 plant species were assayed for inhibition of murine cytomegalovirus and sindbis virus infections. parallel assays were carried out with and without exposure to uva radiation to test for photo-mediation of activity. antiviral activity was observed with 16 of the plant extracts. eight plant extracts have been selected for further studies, with the objective of characterizing the anti ...19911661356
effects of protein kinase c inhibitors on viral entry and infectivity.the protein kinase c inhibitor h-7 (2-20 microm) inhibited dose-dependently the infectivity of the vesicular stomatitis virus on cultured human fibroblasts. electron microscopy showed that h-7 inhibited the viral entry. h-7 also inhibited the infectivity of four other enveloped viruses, herpes simplex i, turkey herpes, vaccinia and sindbis. similar results were obtained using staurosporine (2.5 nm), tamoxifen (40 microm), phloretin (140 microm), or w-7 (40 microm). however, the infectivity of no ...19911659999
protection by dehydroepiandrosterone in mice infected with viral encephalitis.dehydroepiandrosterone (dhea) has a significant protective effect in mice infected with west nile virus (wnv), sindbis virus neurovirulent (svni) and semliki forest virus (sfv). mice injected subcutaneously (sc) with a single injection of dhea (1 g/kg) on the same day or one day pre or post infection with wnv resulted in 40-50% mortality as compared to 100% in control injected mice (p less than 0.05). the drug was effective following a single sc injection or serial intraperitoneal (ip) injection ...19911659799
antiviral activity of the photoactive plant pigment hypericin.the polycyclic compound hypericin, a known photodynamic agent, was investigated for antiviral activity in the presence and absence of light. the three viruses tested: murine cytomegalovirus; sindbis virus; and human immunodeficiency virus type 1, were all susceptible to hypericin; but these antiviral activities were considerably enhanced, in a dose-dependent manner, by exposure to light.19911658826
identification of a putative alphavirus receptor on mouse neural cells.alphaviruses replicate in a wide variety of cells in vitro. the prototype alphavirus, sindbis virus, causes an age-dependent encephalitis in mice and serves as an important model system for the study of alphavirus neurovirulence. to begin to understand the role of cellular virus receptors in the pathogenesis of sindbis virus infection, we developed an anti-idiotypic antibody made in rabbits against a neutralizing monoclonal antibody specific for the e2 surface glycoprotein. the anti-idiotypic an ...19911658382
comparative behavior of lysosomes and the pre-lysosome compartment (plc) in in vivo cell fusion experiments.interspecies cell fusion was used to compare protein intermixing within the mannose 6-phosphate receptor (mpr)-enriched pre-lysosome compartment (plc) and within the mpr-negative lysosomal compartment. both compartments were positive for lysosomal glycoprotein (lgp) membrane markers but were morphologically distinct. in most experiments, rat-mouse cell syncytia were formed by u.v.-inactivated sindbis virus-mediated fusion. by immunogold electron microscopy of syncytia, extensive intermixing of s ...19911658017
mutational analysis of a virulence locus in the e2 glycoprotein gene of sindbis virus.the substitution of arginine for serine at position 114 of glycoprotein e2 in several biological and recombinant sindbis virus mutants was shown previously to attenuate the virus for neonatal mice and also to accelerate virus penetration into bhk cells. to further examine the genetically linked effects on both virus penetration into cultured cells and pathogenesis in vivo, mutants containing each of 16 different amino acid coding changes at this position were generated by site-directed mutagenes ...19911656101
antiviral activities of hypericin.hypericin, a photodynamic plant quinone, readily inactivated murine cytomegalovirus (mcmv), sindbis virus, and human immunodeficiency virus type 1 (hiv-1), especially on exposure to fluorescent light. sindbis virus was significantly more sensitive than mcmv. the inactivated mcmv, when used to infect cells, was incapable of synthesizing early or late viral antigens. in addition to this direct virucidal effect, when hypericin was added to cells infected with viable mcmv, inhibition was also observ ...19911650164
site-directed mutations in sindbis virus e2 glycoprotein's cytoplasmic domain and the 6k protein lead to similar defects in virus assembly and mutagenesis was used to obtain four mutants with amino acid replacements in the cytoplasmic domain of the e2 glycoprotein and three with replacements in the 6k protein of sindbis virus. all but one of these mutants yielded progeny virus after transfection of chicken embryo fibroblasts with rna prepared by in vitro transcription of the virus cdna; however, even this nonproducer mutant made virus structural proteins in the transfected cells. the other six mutants divided into two gro ...19911647069
conservation of the putative methyltransferase domain: a hallmark of the 'sindbis-like' supergroup of positive-strand rna comparisons of the large proteins involved in the replication of viral rna have revealed a novel domain located near the n termini of these proteins and conserved throughout the so-called 'sindbis-like' supergroup of positive-strand rna viruses. this domain encompasses four distinct conserved motifs, with motifs i, ii and iv containing an invariant his residue, the aspxxarg signature and an invariant tyr residue, respectively. each of the two large groups of viruses within this ...19921645151
intermixing of resident golgi membrane proteins in rat-hamster polykaryons appears to depend on organelle coalescence.we have used the synchronized formation of a mixed cytoplasm upon heterokaryon formation as a model for investigating the cisternal-specific transport of resident proteins between neighboring golgi apparatus. rat nrk and hamster 15b cells were fused by uv-inactivated sindbis virus and then incubated for various time periods in the presence of cycloheximide. the resident golgi apparatus proteins, rat gimpc and golgp 125, were localized with species-specific monoclonal antibodies. immunofluorescen ...19921639086
von willebrand factor characterization of a severe dry-heat treated factor viii concentrate, ahf (high purity).eight batches of a severe dry-heat treated (80 degrees c for 72 hours) factor viii concentrate manufactured by the commonwealth serum laboratories (csl ltd.) were analysed for the following von willebrand factor-related (vwf) activities: ristocetin cofactor activity (vwf:rcof), collagen binding activity (cba), vwf antigen levels (vwf:ag), vwf multimeric analysis and 2-stage fviii clotting activity (viii:c). the average potency per vial of vwf:ag was 440 +/- 80 units, vwf:rcof 500 +/- 60 units, c ...19921631803
a pasteurized therapeutic plasma.a process to subject pooled human plasma to a viral inactivation treatment by heating in the liquid state for 10 hrs at 60 degrees c (pasteurization) has been designed and evaluated. activity recovered from clotting factors and protease inhibitors exceeded 80%. overall clotting activity remained good. no activation of coagulation factors was detected. the process did not generate aggregates. no side effects (toxicity, hypotension, variation in heart rate, thrombogenicity) could be detected in an ...19921623326
crystallization of sindbis virus and its nucleocapsid.crystals of sindbis virus, which contains a lipid-bilayer membrane, have been grown using polyethylene glycol. the space group is r32, a = b = 640 a, c = 1520 a. the crystals are highly mosaic, and recorded diffraction is therefore restricted to spacings of about 30 a. the crystals show that the packing of glycoproteins e1 and e2 in the icosahedral outer shell is sufficiently precise that it permits regular and repeated interactions between virus particles in the lattice. crystals of sindbis nuc ...19921619658
inactivation of viruses in red cell and platelet concentrates with aluminum phthalocyanine (aipc) sulfonates.aluminum phthalocyanine tetrasulfonates (aipcs) are photoactive compounds with absorption maxima at 665-675 nm. the inactivation of viruses (vesicular stomatitis virus, vsv; human immunodeficiency virus, hiv) added to either whole blood or red blood cell concentrates (rbcc) and platelet concentrates (pc) on treatment with tetrasulfonated aipc (aipcs4) was evaluated. treatment of rbcc with 10 microm aipcs4 and 44 j/cm2 visible light resulted in the inactivation of greater than or equal to 10(5.5) ...19921617188
merocyanine-sensitized photoinactivation of enveloped viruses.a wide range of enveloped viruses, including human herpes simplex virus type 1, human cytomegalovirus, human t cell leukemia/lymphoma virus type i, human immunodeficiency virus type 1, sindbis virus, and friend erythroleukemia virus, are highly susceptible to merocyanine 540 (mc 540)-sensitized photoinactivation. by contrast, human pluripotent hematopoietic stem cells, red cells, factor viii, and von willebrand factor are much less sensitive. this suggests that mc 540 may be useful for the inact ...19921617187
morphogenesis of sindbis virus in three subclones of aedes albopictus (mosquito) cells.the morphogenesis of sindbis virus in three aedes albopictus subcloned cell lines was examined. each line was distinguishable with respect to morphology, cytopathic response to infection, and progeny yield. c7-10 cells, which produced the highest titers of virus and exhibited the most severe cytopathic response, were characterized ultrastructurally by the presence of budding particles at the cell surface and at the membranes of internal vesicles. c6/36 cells, which displayed a moderate cytotoxic ...19921602541
the efficient intracellular sequestration of the insulin-regulatable glucose transporter (glut-4) is conferred by the nh2 terminus.glut-4 is the major facilitative glucose transporter isoform in tissues that exhibit insulin-stimulated glucose transport. insulin regulates glucose transport by the rapid translocation of glut-4 from an intracellular compartment to the plasma membrane. a critical feature of this process is the efficient exclusion of glut-4 from the plasma membrane in the absence of insulin. to identify the amino acid domains of glut-4 which confer intracellular sequestration, we analyzed the subcellular distrib ...19921577853
opposite polarity of virus budding and of viral envelope glycoprotein distribution in epithelial cells derived from different tissues.we compared the surface envelope glycoprotein distribution and the budding polarity of four rna viruses in fischer rat thyroid (frt) cells and in caco-2 cells derived from a human colon carcinoma. whereas both frt and caco-2 cells sort similarly influenza hemagglutinin and vesicular stomatitis virus (vsv) g protein, respectively, to apical and basolateral membrane domains, they differ in their handling of two togaviruses, sindbis and semliki forest virus (sfv). by conventional em sindbis virus a ...19921572895
effect of electric charged molecules on sindbis virus hemagglutination and hemolysis.the role of electrostatic interactions in the attachment and fusion at acidic ph of sindbis virus (snv) with goose erythrocytes was studied, investigating the effect of several anionic and cationic polyelectrolytes on snv hemagglutination and hemolysis. in order to establish the target of active drugs, the compounds were incubated either with the virus particles or with the erythrocytes. dextran sulfate was the only compound able to inhibit the attachment of snv to the erythrocytes. fusion of vi ...19921556956
rna-dependent rna polymerase consensus sequence of the l-a double-stranded rna virus: definition of essential domains.the l-a double-stranded rna virus of saccharomyces cerevisiae makes a gag-pol fusion protein by a -1 ribosomal frameshift. the pol amino acid sequence includes consensus patterns typical of the rna-dependent rna polymerases (ec of (+) strand and double-stranded rna viruses of animals and plants. we have carried out "alanine-scanning mutagenesis" of the region of l-a including the two most conserved polymerase motifs, sg...t...nt..n (. = any amino acid) and gdd. by constructing and anal ...19921549580
disulfide bonds are essential for the stability of the sindbis virus envelope.sindbis virus is a membrane-containing virus which has two glycoproteins organized in an icosahedral lattice. protein-protein associations have been identified which participate in the formation of the icosahedron and these associations are stabilized by intramolecular disulfide bridges (anthony, r. p., and brown, d. t., 1990, j. virol. 65, 1187-1194). the present study further examines the role of disulfides in the structure and function of sindbis virus by following the effect of dithiothreito ...19921529537
viral neuroinvasion and encephalitis induced by lipopolysaccharide and its mediators.the present study was designed to test the effect of bacterial endotoxin on penetration of viruses into the central nervous system (cns). as a model we used two neurovirulent viruses that lack neuroinvasive capacity: west nile virus-25 (wn-25) and neuroadapted sindbis virus (svn). administration of lipopolysaccharide (lps, 100 micrograms/mouse) to cd-1 mice, followed by wn-25 inoculation resulted in 83% encephalitis and death, compared with less than 5% in controls. the results in svn-inoculated ...19921512538
[studies on the production of endogenous cytokines in patients with renal cell carcinoma].this study was undertaken to determine the production of tumor necrosis factor (tnf) and interferon-gamma (ifn-gamma) by biological response modifier (brm) in patients with renal cell carcinoma (rcc). peripheral blood mononuclear cells (pbmc), which were donated from thirteen patients with rcc and five healthy controls, were cultured with streptococcal preparation, ok432, and/or macrophage-colony stimulating factor (m-csf), and the tnf levels and ifn-gamma levels in the supernatant were evaluate ...19921507728
dynamics of transmembrane proteins during sindbis virus budding.label-fracture and immunogold fracture-flip techniques are used to address at the ultrastructural level the dynamics of viral and cellular transmembrane proteins during the budding of sindbis virus on the plasma membrane of infected cells. immunolabeling with anti-sindbis spike antibodies shows that the viral proteins are mostly in clusters, all associated with budding viruses. ultrastructural observation of the unlabeled freeze-fractured plasma membranes shows that membrane particles aggregate ...19921500437
identification of the active site residues in the nsp2 proteinase of sindbis virus.the nonstructural polyproteins of sindbis virus are processed by a virus-encoded proteinase which is located in the c-terminal domain of nsp2. here we have performed a mutagenic analysis to identify the active site residues of this proteinase. substitution of other amino acids for either cys-481 or his-558 completely abolished proteolytic processing of sindbis virus polyproteins in vitro. substitutions within this domain for a second cysteine conserved among alphaviruses, for four other conserve ...19921448929
attenuation of sindbis virus neurovirulence by using defined mutations in nontranslated regions of the genome rna.we examined a panel of sindbis virus mutants containing defined mutations in the 5' nontranslated region of the genome rna, in the 3' nontranslated region, or in both for their growth in cultured cells and virulence in newborn mice. in cultured cells, these viruses all had defects in rna synthesis and displayed a wide range of growth rates. the growth properties of the mutants were often very different in mouse cells from those in chicken cells or in mosquito cells. we hypothesize that host fact ...19921433509
role of ribosomes in semliki forest virus nucleocapsid uncoating.the mechanism by which semliki forest virus nucleocapsids are uncoated was analyzed in living cells and in vitro. in bhk-21 cells, uncoating occurred with virtually complete efficiency within 1 to 2 min after the nucleocapsids entered the cytoplasm. it was inhibited by monensin, which blocks nucleocapsid penetration from endosomes. as previously shown for sindbis virus (g. wengler and g. wengler, virology 134:435-442, 1984), the capsid proteins from incoming nucleocapsids became associated with ...19921433506
the structure determination of sindbis virus core protein using isomorphous replacement and molecular replacement averaging between two crystal forms.the structure of sindbis virus core protein has been determined by a combination of multiple isomorphous replacement and molecular replacement averaging techniques. the multiple isomorphous replacement phase determinations were made for two crystal forms (p2(1) and p4(3)2(1)2) of the core protein. the real-space molecular replacement averaging was subsequently carried out between two copies of the protein per asymmetric unit in the monoclinic form and one copy in the tetragonal form. this greatl ...19921418825
[the isolation and identification of the sindbis virus from migratory birds in estonia].the data on isolation from birds and identification of two strains of alphaviruses in estonia in the territory of vilsandy natural reserve are presented. electron microscopy of purified virions allowed the isolates to be classified into the family of togaviruses, and serological identification (neutralization test, cft) using polyvalent sera and monoclonal antibody showed them to belong to sindbis virus.19921413718
high-affinity laminin receptor is a receptor for sindbis virus in mammalian cells.sindbis virus is an alphavirus with a very wide host range, being able to infect many birds and mammals as well as mosquitoes. we have isolated a monoclonal antibody that largely blocks virus binding to mammalian cells. this antibody was found to be directed against the c-terminal domain of the high-affinity laminin receptor, a 67-kda protein present on the cell surface that binds with high affinity to basement membrane laminin and that is known to be important in development and in tumor invasi ...19921385835
persistence of viral rna in mouse brains after recovery from acute alphavirus encephalitis.little is known about the relationship between recovery from acute viral encephalitis and the clearance of viral genetic material from the central nervous system. in a mouse model of sindbis virus encephalitis, we have previously shown that clearance of infectious virus is mediated by antibody-induced restriction of viral gene expression rather than by cytotoxic destruction of virally infected cells. to explore whether sindbis virus genomes persist in mouse brain after the clearance of infectiou ...19921383564
conformational alteration of sindbis virion glycoproteins induced by heat, reducing agents, or low ph.sindbis virions undergo a conformational rearrangement after attachment to cells but prior to entry, as detected by exposure of epitopes on virus-cell complexes which are not accessible to their cognate monoclonal antibodies on native virions (d. c. flynn, w. j. meyer, and r. e. johnston, j. virol. 64:3643-3653, 1990). the rearrangement did not appear to require transit of virions through a low-ph environment, and the altered virions participated in a productive infection. this naturally occurri ...19921374808
infectious sindbis virus transient expression vectors for studying antigen processing and presentation.sindbis virus (sin) is a small positive-strand enveloped rna virus that infects a broad range of vertebrate and insect cells. a sin vector (called dssin), designed for transient expression of heterologous rnas and proteins, was engineered by inserting a second subgenomic mrna promoter sequence into a nonessential region of the sin genome. by using this vector, dssin recombinants have been constructed that express either bacterial chloramphenicol acetyltransferase, a truncated form of the influen ...19921372987
infectious enveloped rna virus antigenic chimeras.random insertion mutagenesis has been used to construct infectious sindbis virus structural protein chimeras containing a neutralization epitope from a heterologous virus, rift valley fever virus. insertion sites, permissive for recovery of chimeric viruses with growth properties similar to the parental virus, were found in the virion e2 glycoprotein and the secreted e3 glycoprotein. for the e2 chimeras, the epitope was expressed on the virion surface and stimulated a partially protective immune ...19921370348
atomic structure of single-stranded dna bacteriophage phi x174 and its functional implications.the mechanism of dna ejection, viral assembly and evolution are related to the structure of bacteriophage phi x174. the f protein forms a t = 1 capsid whose major folding motif is the eight-stranded antiparallel beta barrel found in many other icosahedral viruses. groups of 5 g proteins form 12 dominating spikes that enclose a hydrophilic channel containing some diffuse electron density. each g protein is a tight beta barrel with its strands running radially outwards and with a topology similar ...19921370343
high resolution removal of virus from protein solutions using a membrane of unique structure.we describe a new class of membrane that has the capability of removing particles such as viruses from solution with resolution and reproducibility superior to that of conventional membranes. this composite membrane is composed of a pre-formed microporous membrane plus a thin asymmetric, finely porous retentive layer that is quite different from conventional ultrafilters. the protein sieving characteristics of this membrane are nearly equivalent to, but slightly less than, that of conventional 1 ...19921368775
a novel variant of sindbis virus is both neurovirulent and neuroinvasive in adult mice.a strain of sindbis virus (sv), recently isolated from mosquitoes in israel, was used as a source for variants which differ in neuroinvasiveness and virulence that were generated by serial passage of sv in suckling and weanling mouse brain. at the 15th passage a neurovirulent variant was observed and designated svn (neurovirulent). after 7 more passages in weanling mouse brains, another variant was observed and designated svni (neuroinvasive) and both were isolated and purified. all strains caus ...19921346243
expression of the chloramphenicol acetyltransferase gene in aedes albopictus (c6/36) cells using a non-infectious sindbis virus expression vector.genomic rna was transcribed in vitro from the non-infectious sindbis (sin) virus expression vector (ptrcat) and introduced into c6/36 (aedes albopictus) cells by liposome-mediated transfections. the chloramphenicol acetyltransferase (cat) polypeptide expressed within cells was detected by an indirect immunofluorescent assay directly into 24-well polystyrene tissue culture plates. approximately 1 in 1000 c6/36 cells showed fluorescence when the transfection was optimized. cat enzyme activity was ...19921343776
susceptibility of aedes krombeini cell line to some arboviruses.the susceptibility of the newly established ae. krombeini cell line (nivi-ak-453) to six arboviruses, belonging to four different families, was studied. sindbis (sind), vesicular stomatitis (vsv) chandipura (chp) and african horse sickness (ahs) viruses multiplied in these cultures. a four-to-five-fold increase in the virus titres was observed. the maximum titre of sind, vsv, chp and ahs viruses were observed on 1st, 4th, 3rd and 10th post infection days, respectively. a steady and significant i ...19921335966
long term intraparenchymal ig secretion after acute viral encephalitis in mice.oligoclonal bands in the cerebrospinal fluid indicate intrathecal synthesis of ig of restricted heterogeneity and are associated with a number of central nervous system inflammatory diseases. to gain better insight into the persistence of oligoclonal bands found in the central nervous system we studied mice infected with sindbis virus (sv), a rna virus that causes an acute, nonfatal encephalitis in mice. sv was inoculated intracerebrally into weanling mice and brains and spleens were harvested a ...19921334109
structure-activity studies of photoactivated antiviral and cytotoxic tricyclic thiophenes.the photoactivated antiviral and cytotoxic activities of the naturally occurring thiophene, alpha-terthienyl (1), and 15 synthetic analogues were evaluated against murine cytomegalovirus and sindbis virus, and murine mastocytoma cells. after irradiation with near uv light, alpha-terthienyl and most of its analogues had significant toxicity, with minimum inhibitory concentrations in the range of 0.02-40 microm. in the absence of near uv irradiation, only one analogue had antiviral activity and fi ...19921333615
identification of a sequence element in the alphavirus core protein which mediates interaction of cores with ribosomes and the disassembly of cores.early in infection core protein is transferred from alphavirus cores to ribosomes (wengler and wengler, 1984, virology 134, 435-442) and it has been suggested that ribosome binding is a property of alphavirus core protein which is involved in core disassembly. here we describe in vitro analyses of this transfer. sindbis virus cores, incubated with ribosomes either in a reticulocyte lysate or in buffer, are disassembled with a concomitant transfer of core protein to the large ribosomal subunit. p ...19921333127
[the identification of alphaviruses by using cdna probes complementary to the 3'-terminal of the viral genome].venezuelan equine encephalomyelitis, eastern equine encephalomyelitis and sindbis viruses, as well as members of various serological groups of alphaviruses were identified using synthesized molecular probes complementary to 3'-terminus of the molecule of the appropriate genomic rna: 32p-single-stranded kdna and e. coli-cloned 32p-double-stranded kdna. a high species-specificity of kdna-probes was demonstrated. the sensitivity of the method was 1 ng of viral rna overlayed on the nitrocellulose fi ...19921332260
isolation of a cell line for rapid and sensitive histochemical assay for the detection of herpes simplex virus.a cell line which can be used in a simple, sensitive, and rapid histochemical assay was isolated for detection of herpes simplex virus (hsv). the cell line was derived by selection of g418 resistant colonies following co-transfection of baby hamster kidney cells with a plasmid which contains a g418 antibiotic resistance marker and a plasmid which contains the escherichia coli lacz gene placed behind an inducible hsv promoter. the promoter is from hsv-1ul39 which encodes icp6, the large subunit o ...19921325470
expression of the nonstructural proteins of sindbis virus in insect cells by a baculovirus vector.the genome of sindbis virus encodes the polypeptides that are required for the replication and transcription of the virus rna in infected cells. these polypeptides are translated as a polyprotein that is co- and post-translationally cleaved by an autoproteinase to give rise to four polypeptides designated nsp1, nsp2, nsp3 and nsp4. we have initiated a study of the functions of these proteins by expressing them in the autographa californica baculovirus polyhedrin expression system. spodoptera fru ...19921320794
the immune response in viral encephalitis.the central nervous system (cns) offers a unique organ system in which to study viral immunopathogenesis. the presence of the blood-brain barrier that restricts entry of cells and protein, the restricted expression of mhc antigens and the nonrenewable nature of the neuronal cell population offer challenges to the immune system for viral clearance and increase the chances for viral persistence. we have used sindbis virus encephalitis in mice as a model system for the study of the development of i ...19921319767
solvent/detergent-treated plasma: a virus-inactivated substitute for fresh frozen plasma.fresh frozen plasma (ffp) is prepared in blood banks world-wide as a by-product of red blood cell concentrate preparation. appropriate clinical use is for coagulation factor disorders where appropriate concentrates are unavailable and when multiple coagulation factor deficits occur such as in surgery. viral safety depends on donor selection and screening; thus, there continues to be a small but defined risk of viral transmission comparable with that exhibited by whole blood. we have prepared a v ...19921310064
utilization of heterologous alphavirus junction sequences as promoters by sindbis virus.we used sindbis virus, an alphavirus, as a model to study the evolution of the recognition of viral cis-acting sequences. during the life cycle of alphaviruses, a full-length minus-strand rna is made and serves as a template for both genomic rna replication and subgenomic mrna transcription. transcription initiates at an internal promoter site, the junction sequence, to produce a subgenomic mrna. the junction sequences of alphaviruses are highly conserved, but they do contain a number of base di ...19921309918
divergent envelope e2 alphavirus sequences spanning amino acids 297 to 352 induce in mice virus-specific protective immunity and antibodies with complement-mediated cytolytic activity.we have proposed a general algorithm for identification of potential immunoprotective domains (cassettes) on the envelope e2 polypeptide of alphaviruses (h. grosfeld, b. velan, m. leitner, s. cohen, s. lustig, b.e. lachmi, and a. shafferman, j. virol. 63:3416-3422, 1989). to assess the generality of our approach, we compared analogous e2 cassettes from sindbis virus (sin) and semliki forest virus (sfv), two alphaviruses which are philogenetically very remote. the antigenically distinct sfv e2 an ...19921309890
inhibitory effects of hsp70 chaperones on nascent polypeptides.several of the major heat shock proteins (hsps) function normally as molecular chaperones to prevent aggregation of immature polypeptides and thereby facilitate folding and oligomerization. to determine their effect on nascent polypeptides, we added purified preparations of different isoforms of hsp70 to in vitro translation reactions primed by the 26s mrna of sindbis virus, which encodes an autoprotease that functions cotranslationally, or by the mrna encoding the yeast vacuolar h+atpase, which ...19921304386
[the antiviral action of a modified bacterial ribonuclease].the antiviral activity of a bacterial ribonuclease conjugate with chitosane of kamchatka crab (in a form of water soluble chito-oligosaccharides) has been studied. the conjugate inhibitory activity for a and b viruses as well as to sindbis arbovirus in tissue cultures is shown. the preparation efficiency at intramuscular and intranasal administration was observed at experimental influenza infection of white mice.19921302513
[effect of various adamantane compounds on the reproduction of sindbis virus. isolation and properties of a resistant strain].rimantadine and its structural analogs, i. e. amide of 1-adamantane carboxylic acid (aaca) and 1-adamantane acetic acid amide, were shown to be able to inhibit reproduction of sindbis virus in culture vero cells. aaca had the maximum antiviral activity. subcultures of the initial sensitive population of sindbis virus in the presence of aaca led to formation of mutants resistant to aaca as well as to rimantadine, adamantane acetic acid amide and ammonium chloride. the sindbis virus population was ...19921296534
constituents of eriobotrya japonica. a study of their antiviral properties.the chcl3 extract of eriobotrya japonica from an italian source was shown to contain four new triterpene esters, namely, 23-trans-p-coumaroyltormentic acid [1], 23-cis-p-coumaroyltormentic acid [2], 3-o-trans-caffeoyltormentic acid [3], and 3-o-trans-p-coumaroylrotundic acid [4], in addition to three common ursolic acid derivatives 5, 6, and 7. an investigation of the antiviral properties of compounds 1-7 revealed that only 3 significantly reduced rhinovirus infection. the compounds were ineffec ...19921279126
role of the immune response in age-dependent resistance of mice to encephalitis due to sindbis to eight-week-old mice were studied after subcutaneous inoculation of sindbis virus. local replication at the site of inoculation, transient viremia, and invasion of the brain were found in mice of all ages, although the quantities of virus were greater in younger mice. death occurred in 100% of one-week-old mice, 28% of two-week-old mice, and none of the mice four weeks old or older. pathologic examination of the brains on day 7 after infection revealed a mononuclear inflammatory infiltrat ...19761262711
genetic exclusion and stable complementation of sindbis an effort to enhance genetic interactions by eliminating spatial or physical barriers between variants of sindbis virus mgcl2 was used to aggregate infecting viral particles. mixing viral samples in a 1:1 ratio with 0.5 m mgcl2 produced maximal reduction in plaque forming units (pfu) with minimal cell damage due to mgcl2. aggregate size was determined to be about 7 pfu. samples taken at 3,5 and 10 hours after infection with mixed aggregates composed of large and small plaque forming virus ind ...19761259595
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