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age-dependent susceptibility to fatal encephalitis: alphavirus infection of neurons.sindbis virus encephalitis in mice provides a model for studying age-dependent susceptibility to acute viral encephalitis. the ar339 strain of sv causes fatal encephalitis in newborn mice, but weanling mice recover uneventfully. increased virulence for older mice is associated with a single amino acid change from gln to his at position 55 of the e2 glycoprotein. weanling mice with normal immune systems clear infectious virus from neurons through an antibody-mediated mechanism. this does not happ ...19948032263
antibody-mediated clearance of viruses from the mammalian central nervous system.the novel role of antibody in clearing virus from the central nervous system without the help of other immune effectors is an important phenomenon that has only recently been documented. possible routes for antibodies across the blood-brain barrier and how they work in the cns are discussed here.19938044464
genetic analysis of the nsp3 region of sindbis virus: evidence for roles in minus-strand and subgenomic rna synthesis.sindbis virus nonstructural polyproteins and their cleavage products are believed to be essential components of viral rna replication and transcription complexes. although numerous studies have investigated the effect of mutations in nsp1-, nsp2-, and nsp4-coding regions on sindbis virus-specific rna synthesis, relatively little is known about the function of the region encoding nsp3. nsp3 is a phosphoprotein comprising two regions: an n-terminal portion which is highly conserved among alphaviru ...19948057460
multivalent rna probes and their use in the quantitation of multiple and non-homologous rna species immobilized onto nylon membranes. 19948065945
analysis of the molecular basis of neuropathogenesis of rna viruses in experimental animals: relevance for human disease?rna viruses with segmented genomes were the first model used for molecular analysis of viral neuropathogenesis, since they could be analysed genetically by reassortment. four viruses with non-segmented genomes have been used as models of neurovirulence and demyelinating disease: jhm coronavirus, theiler's virus, sindbis virus and semliki forest virus (sfv). virus gene expression in the central nervous system of infected animals has been measured by in situ hybridization and immunocytochemistry. ...19948072672
inactivation of free and cell-associated human immunodeficiency virus in platelet suspensions by aminomethyltrimethylpsoralen and ultraviolet light.it has previously been reported that 40 micrograms per ml of aminomethyltrimethylpsoralen (amt) plus 2.4 to 7.2 j per cm2 of ultraviolet a (uva) light inactivated 4 to 6 log10 of several model viruses in platelet suspensions. this inactivation was achieved while satisfactory levels of platelet count, ph, morphology, aggregation, and hemostatic effectiveness were maintained.19948073484
formation and intracellular localization of hepatitis c virus envelope glycoprotein complexes expressed by recombinant vaccinia and sindbis viruses.hepatitis c virus (hcv) encodes two putative virion glycoproteins (e1 and e2) which are released from the polyprotein by signal peptidase cleavage. in this report, we have characterized the complexes formed between e1 and e2 (called e1e2) for two different hcv strains (h and bk) and studied their intracellular localization. vaccinia virus and sindbis virus vectors were used to express the hcv structural proteins in three different cell lines (hepg2, bhk-21, and pk-15). the kinetics of associatio ...19948083956
alphavirus nsp3 functions to form replication complexes transcribing negative-strand rna.the alphavirus mutant sindbis virus hr ts4, which has been assigned to the a complementation group, possessed a selective defect in negative-strand synthesis that was similar although not identical to that observed for the b complementation group mutant ts11 (y.-f. wang, s. g. sawicki, and d. l. sawicki, j. virol. 65:985-988, 1991). the causal mutation was identified as a change of a c to a u residue at nucleotide 4903 in the nsp3 open reading frame that predicted a change of ala-268 to val. thu ...19948083984
murine t-helper cell immune response to recombinant vaccinia-venezuelan equine encephalitis virus.the t-helper (th) cell immune response following immunization of c3h (h-2k) mice with a recombinant vaccinia (vac) virus (tc-5a) expressing the structural proteins (capsid, e1 and e2) of the attenuated vaccine strain (tc-83) of venezuelan equine encephalitis (vee) virus was compared with the immune response induced in mice after immunization with tc-83 virus. tc-5a virus elicited th cells that strongly recognized both vac and tc-83 viruses in in vitro lymphoblastogenesis tests. th-cell activatio ...19948085379
the configuration of sindbis virus envelope proteins is stabilized by the nucleocapsid protein.we have previously provided evidence that a strong and precise interaction of the sindbis virus nucleocapsid with the cytoplasmic tail of e2 is critical for the function of the mature virion and that changes in this association may affect infectivity (21). in this study, we examined the effects of temperature-sensitive defects in capsid protein on virus infectivity and glycoprotein function. the two sindbis virus mutants chosen were ts2 and ser180/gly183, which contain amino acid substitutions i ...19948091681
removal and inactivation of enveloped and non-enveloped viruses during the purification of a high-purity factor ix by metal chelate affinity chromatography.virus reduction during the copper chelate affinity chromatography stage used during the purification of a new high-purity factor ix (bpls 9mc) has been investigated. virus reduction for the enveloped virus sindbis was 6.5 log, a value which included approximately 2 log of inactivation due to the use of an acidic wash buffer (ph 4.4) during chromatography. in the case of the non-enveloped hepatitis-a-like poliovirus, which is acid-resistant, the virus reduction value was 4.0 log and was exclusive ...19948091741
an in-frame insertion into the sindbis virus 6k gene leads to defective proteolytic processing of the virus glycoproteins, a trans-dominant negative inhibition of normal virus formation, and interference in virus shut off of host-cell protein synthesis.encoded in the genomes of all alphaviruses is a hydrophobic polypeptide of 55 amino acids, which is post-translationally modified with 4 covalently bound palmitic acids. this protein, noted as 6k, associates with membranes and is transported along with the two virus transmembranal glycoproteins to the site of virus assembly at the infected cell's plasma membrane. previous studies showed that mutations in the 6k protein led to the slow release of aberrant, multi-cored infectious virions. in this ...19938094927
the organization of the spike complex of semliki forest virus.semliki forest virus (sfv) is an enveloped animal virus comprising an icosahedral nucleocapsid surrounded by a membrane containing 80 transmembrane, trimeric spikes. sfv was treated with the non-ionic detergent n-octyl beta-d-glucopyranoside (octylglucoside) and analysed by cryo-electron microscopy and image reconstruction to explore the interaction between the spikes and the capsid. comparison of the structure of detergent treated sfv (dsfv) with sfv by three-dimensional image reconstruction fr ...19948107141
comparison of the effects of sindbis virus and sindbis virus replicons on host cell protein synthesis and cytopathogenicity in bhk cells.infection of bhk cells by sindbis virus leads to rapid inhibition of host cell protein synthesis and cytopathic effects (cpe). we have been studying these events to determine whether the expression of a specific viral gene is required and, in the present study, have focused our attention on the role of the structural proteins--the capsid protein and the two membrane glycoproteins. we tested a variety of sindbis viruses and sindbis virus replicons (virus particles containing an rna that is self-r ...19948107233
regulation of sindbis virus rna replication: uncleaved p123 and nsp4 function in minus-strand rna synthesis, whereas cleaved products from p123 are required for efficient plus-strand rna synthesis.nonstructural proteins of sindbis virus, nsp1, nsp2, nsp3, and nsp4, as well as intermediate polyproteins, are produced from two precursor polyproteins, p123 and p1234, by a proteolytic enzyme encoded in the c-terminal half of nsp2. we studied the requirements for and the functions of the intermediate and mature processing products for sindbis virus rna synthesis by using site-directed mutants which have a defect(s) in processing the 1/2, 2/3, or 3/4 cleavage sites either singly or in various co ...19948107248
the expression of chloramphenicol acetyltransferase in aedes albopictus (c6/36) cells and aedes triseriatus mosquitoes using a double subgenomic recombinant sindbis virus.genomic rna was transcribed in vitro from the double subgenomic recombinant sindbis (sin) virus expression vector, pte/3'2j/cat, and transfected into bhk-21 cells to generate recombinant virus stocks. te/3'2j/cat virus was used to infect c6/36 (aedes albopictus) cells and adult female aedes triseriatus. when c6/36 cells were infected with te/3'2j/cat virus at a multiplicity of infection (moi) of greater than 20, 100% of the cells expressed cat. the number of cat polypeptides expressed per cell a ...19948111422
sindbis virus-induced inhibition of protein synthesis is partially reversed by medium containing an elevated potassium concentration.infection of cultured vertebrate cells by sindbis virus, an alphavirus, results in a reduction in the overall rate of protein synthesis and in selective termination (shutoff) of host-specified protein synthesis. the shutoff of host protein synthesis by sindbis virus has been temporally correlated with a decrease in intracellular k+ concentration (and an increase in intracellular na+ concentration) which occurs as a consequence of virus-mediated inhibition of the plasma membrane-associated na+/k+ ...19948113764
size exclusion removal of model mammalian viruses using a unique membrane system, part i: membrane qualification.we have previously described a new class of composite membrane that has the capability to efficiently remove particles, including viruses, from protein solution. the qualification of this membrane requires that it reproducibly and predictably remove model mammalian viruses. using the viresolve/70 membrane, the mammalian viruses polio, simian virus-40, sindbis, reovirus type 3 and rauscher murine leukemia virus are shown to be reproducibly removed via a sieving mechanism. mammalian virus retentio ...19938117441
size exclusion removal of model mammalian viruses using a unique membrane system, part ii: module qualification and process simulation.the performance of a fabricated device may be influenced by the characteristics of the fluid management within the device and reproducibility with which the device is manufactured. the performance of the viresolve/70 membrane is not diminished when incorporated into a fabricated module. the viresolve/70 fabricated modules are shown to reproducibly retain viruses via a sieving mechanism, independent of virus type or character, in excellent agreement with the base membrane retention coefficients r ...19938117442
a 55-kda protein induced in aedes albopictus (mosquito) cells by antiviral protein.we have previously shown that the antiviral protein (avp) produced by sindbis virus-infected aedes albopictus (mosquito) cells (riedel and brown, j. virol. 29, 51-60, 1979) blocks sindbis viral rna synthesis and stimulates its own production when applied to uninfected a. albopictus cells (luo and brown, virology 194, 44-49, 1993). from a virus-sensitive (wild-type) mosquito cell line (u4.4) we produced a virus-resistant cell line (l4.4) by exposing u4.4 cells to the avp. l4.4 cells constitutivel ...19948128621
interactions between sindbis virus rnas and a 68 amino acid derivative of the viral capsid protein further defines the capsid binding site.in previous studies of encapsidation of sindbis virus rna, we identified a 570nt fragment (nt 684-1253) from the 12 kb genome that binds to the viral capsid protein with specificity and is required for packaging of sindbis virus defective interfering rnas. we now show that the capsid binding activity resides in a highly structured 132nt fragment (nt 945-1076). we had also demonstrated that a 68 amino acid peptide derived from the capsid protein retained most of the binding activity of the origin ...19948139918
viral safety of solvent-detergent treated blood products.laboratory research commencing in 1982 led to licensing in the united states in 1985 of a solvent/detergent (sd)-treated anti-haemophilic factor (ahf) concentrate. licensing was based on (a) studies demonstrating the inactivation of several marker viruses [vesicular stomatitis virus (vsv), sindbis virus, sendai virus], human immunodeficiency virus (hiv), hepatitis b virus (hbv), and non-a, non-b hepatitis virus [nanbhv; now known to be principally hepatitis c virus (hcv)] added to ahf just befor ...19938174797
chromatographic removal of viruses from plasma derivatives.progress in protein separation technology has led to the development of a new generation of plasma derivatives, generally prepared by procedures involving one or several chromatographic steps. in addition to providing two to three log purification factors of several therapeutic products, with regard to some protein contaminants, chromatography has been shown to improve the potential safety of new plasma derivatives by contributing to the removal of plasma-borne viruses. indeed, validation studie ...19938174804
structural features of the gtp-binding defective rab5 mutants required for their inhibitory activity on endocytosis.rab5 is a ras-like small gtpase that regulates early events of endocytosis. previous work indicates that two gtp-binding defective rab5 mutants (rab5:s34n and rab5:n133i) are dominant inhibitors of endocytosis. in this report, we have initiated experiments to address the structural features necessary for the inhibitory activity of these two rab5 mutants. second-site mutations were introduced into rab5:s34n and rab5:n133i, respectively, and the resulting double mutants were expressed in cultured ...19948182071
development and small-scale production of a severely heated factor viii concentrate.the small-scale production of a severely heated factor viii concentrate is described. as starting material for the production 48 units of fresh frozen plasma from whole-blood donations or 24 units of plasma from apheresis are used. during a glycine and sodium chloride fractionation, contaminating proteins are removed from a pooled extract of single-donor cryoprecipitates. the resulting factor viii-rich precipitate is redissolved in freeze-drying buffer and this solution is desalted by diafiltrat ...19948184598
effect of monosaccharides during severe dry heat treatment of coagulation factor viii concentrates.during product development of a factor viii concentrate (dutch blood banks) the conversion from unsterilized to autoclaved freeze-drying buffer caused impaired product characteristics after severe dry heat treatment (80 degrees c for 72 h). analysis of the freeze-drying buffers showed the presence of fructose and glucose in heated buffers, resulting from hydrolysis of sucrose. the detrimental effect of glucose and fructose on solubility, yield of factor viii and color of the heat-treated product ...19948184599
the effects of alphavirus infection on neurons.sindbis virus is an alphavirus that causes encephalitis in mice. the primary target cells for central nervous system infection are neurons. the outcome of neuronal infection is dependent on the age of the mouse at the time of infection (maturity of the neuron) and the strain of virus used for infection (virulence of the virus). sindbis virus causes neuronal death by inducing apoptosis. as neurons mature, they become resistant to virus-induced apoptosis, resulting in a persistent infection. host ...19948185292
construction of rubella virus genome-length cdna clones and synthesis of infectious rna transcripts.plasmids containing a complete cdna copy of the rubella virus (rub) genomic rna were constructed. transfection into cell culture of genome-length rna transcribed in vitro from one of these cdna clones, robo102, resulted in the production of virus which preserved the genetic and phenotypic characteristics of the parental virus from which the cdna clone was derived. prior to construction of the rub genome-length cdna clones, the 5'-terminal sequence of the rub genomic rna was determined to be 5'ca ...19948189494
neurovirulent strains of alphavirus induce apoptosis in bcl-2-expressing cells: role of a single amino acid change in the e2 glycoprotein.the isolation and sequence comparison of avirulent and neurovirulent strains of polio virus, alpha virus, herpes virus, immunodeficiency virus, and other viruses have identified genetic changes that are required to cause disease in the nervous system. the molecular mechanisms by which these genetic changes result in neurovirulence are unknown. an avirulent laboratory strain of the alphavirus sindbis kills most cultured cell lines not by lethal parasitism, but by inducing apoptosis or programmed ...19948197207
molecular organization and replication of hepatitis e virus (hev).the recently characterized fecal-orally transmitted agent of hepatitis e (formerly known as enterically transmitted non-a, non-b hepatitis) has been determined to be a new type of positive strand rna virus. the complete sequencing of four different geographic isolates of the hepatitis e virus (hev) has confirmed a similar genetic organization not previously recognized in nonenveloped positive strand rna viruses. the approximately 7.5 kb rna genome (including polya tail) has nonstructural genes l ...19938219799
structure-function relationship of the small gtpase rab5.overexpression of rab5 via a sindbis virus vector resulted in a 2-3-fold stimulation of horseradish peroxidase uptake in bhk-21 cells. based on this functional assay of rab5 activity, we conducted extensive mutational analysis of the structure-function relationship of rab5. a total of 21 deletion and substitution mutations were created and their effects on rab5 activity were examined. deletion of the entire c-terminal tetrapeptide motif ccsn abolished rab5 activity. a mutant with the last three ...19938226999
virus specificity and isotype expression of intraparenchymal antibody-secreting cells during sindbis virus encephalitis in mice.to study the generation of specific antibody responses within the central nervous system (cns), we have utilized a murine model of acute viral encephalitis. when sindbis virus (sv) is injected intracerebrally into weanling mice it causes an acute non-fatal encephalitis and recovery is primarily dependent on the development of antiviral antibody. we used a modified enzyme-linked immunoassay to determine the number of antibody-secreting cells (asc) specific for sv and their ig isotype in brain, sp ...19938227306
a truncated herpes simplex virus origin binding protein which contains the carboxyl terminal origin binding domain binds to the origin of replication but does not alter its conformation.we have studied the dna binding properties of a polypeptide consisting of the carboxyl terminal 37% of ul9, the herpes simplex virus type 1 (hsv-1) origin of replication binding protein. using a sindbis virus expression system, we expressed and partially purified this truncated form of ul9 (ul9ct) which contains the site-specific dna binding domain. ul9ct specifically recognized ul9 binding sites on a 200 base pair dna fragment containing the hsv origin ori(s) and appeared to bind as a dimer to ...19938255778
expression of toxoplasma gondii p30 as fusions with glutathione s-transferase in animal cells by sindbis recombinant virus. 19938259126
mutations in the nsp1 coding sequence of sindbis virus which restrict viral replication in secondary cultures of chick embryo fibroblasts prepared from aged primary cultures.svmpa, a mutant of sindbis virus (sv), which is able to replicate in aedes albopictus cells treated with mycophenolic acid (mpa) or ribavirin, also has a host range phenotype. this phenotype is most clearly demonstrated by means of efficiency of plaquing (eop) assays on secondary chick embryo fibroblasts (cef) prepared from aged primary cef. for example, in one experiment in which standard sv (svstd) had a relative eop (eop on primary cef divided by eop on secondary cef) of 1.6 the corresponding ...19948259645
a cell line that expresses a reporter gene in response to infection by sindbis virus: a prototype for detection of positive strand rna viruses.we describe a stably transformed cell line (bhksinluc2) that contains a defective sindbis virus genome under the control of a rous sarcoma virus promoter and the luciferase gene downstream of the viral subgenomic rna promoter. this cell line expresses high levels of luciferase activity following infection with sindbis virus and provides a sensitive assay for titering variants of sindbis virus that lack the structural protein genes, in particular, sindbis virus replicons that express heterologous ...19948259675
reversal of the antiviral activity of ribavirin against sindbis virus in ae. albopictus mosquito cells.earlier work in our laboratory has shown that the replication of sindbis virus in aedes albopictus mosquito cells is inhibited by ribavirin (rbv) and mycophenolic acid (mpa) (sarver and stollar (1978) virology 91, 267-282; malinoski and stollar (1980) virology 102, 473-476). we report here that the antiviral effect of rbv and mpa can be reversed by depriving infected cells of methionine or isoleucine, or by treating them with fluorodeoxyuridine (fudr) or cycloleucine. we suggest that, as was the ...19938279817
formation and rearrangement of disulfide bonds during maturation of the sindbis virus e1 glycoprotein.the rigidly ordered icosahedral lattice of the sindbis virus envelope is composed of a host-derived membrane bilayer in which the viral glycoproteins e1 and e2 reside. e1-e1 interactions stabilized by intramolecular disulfide bridges play a significant role in maintaining the envelope's structural integrity (r. p. anthony and d. t. brown, j. virol. 65:1187-1194, 1991; r. p. anthony, a. m. paredes, and d. t. brown, virology 190:330-336, 1992). we have examined the acquisition of disulfide bridges ...19948289384
intracerebral cytokine mrna expression during fatal and nonfatal alphavirus encephalitis suggests a predominant type 2 t cell response.sindbis virus (sv) causes an acute encephalomyelitis in mice. a t cell-dependent inflammatory response is first detected 3 days after infection and includes t cells, b cells, and macrophages. the cytokines produced locally by intrinsic cells of the brain in response to infection and by infiltrating mononuclear cells and their contributions to outcome of infection have not been identified. semiquantitative reverse transcriptase-pcr was used to evaluate the expression of mrnas for il-1 beta, il-2, ...19948301132
dna cleavage, antiviral and cytotoxic reactions photosensitized by simple enediyne compounds.very potent antibiotic antitumor natural products contain a enediyne moiety which, upon thermal activation, is capable of abstracting hydrogens from dna. 1,6-diphenyl-3-hexene-1,5-diyne was selected as a candidate for inducing dna strand breaks photochemically. easily interconverted with light, both geometric isomers 1 and 2 were expected to be phototoxic. as anticipated, they photosensitized the production of strand breaks in double-stranded supercoiled pbr322, and in single-stranded m13 dna. t ...19938301409
insect-transmitted vertebrate viruses: alphatogaviruses.alphatogaviruses, of which sindbis virus (sv) is the prototype, replicate to high titer in the laboratory both in mosquito cells and in vertebrate cells. by studying the replication of sv in mosquito cells as well as in vertebrate cells, we were able to obtain several viral mutants which have novel phenotypes and have contributed to our basic knowledge of this virus family. these include three host range mutants: svap15/21 which replicates normally in mosquito cells but is restricted in vertebra ...19938320181
the signal for translational readthrough of a uga codon in sindbis virus rna involves a single cytidine residue immediately downstream of the termination codon.the nucleotide sequences surrounding termination codons influence the efficiency of translational readthrough. in this report, we examined the sequence requirement for efficient readthrough of the uga codon in the sindbis virus genomic rna which regulates production of the putative viral rna polymerase, nsp4. the uga codon and its neighboring nucleotide sequences were subcloned into a heterologous coding context, and readthrough efficiency was measured by cell-free translation of rna transcripts ...19938331741
efficient production of human gamma interferon in tobacco protoplasts by genetically engineered brome mosaic virus rnas.we succeeded in producing human gamma interferon (ifn-gamma) in tobacco protoplasts in quantity using genetically engineered brome mosaic virus (bmv strain atcc66). this strain of bmv produces two types of coat protein, a full-length coat protein (20k) and a truncated coat protein (19k) which are translated from the first and second initiation codons, respectively. we replaced the truncated coat protein gene with the ifn-gamma gene and synthesized bmv-ifn-gamma chimera rnas using an in vitro tra ...19938336117
sindbis virus pathogenesis: phenotypic reversion of an attenuated strain to virulence by second-site intragenic suppressor mutations.monoclonal antibodies (mabs) specific for the e2c neutralizing antigenic site on the sindbis virus e2 glycoprotein define a pathogenesis domain that affects neonatal mouse virulence. sequence analysis of e2c mab escape mutants showed that the domain included e2 amino acids 62, 96 and 159. the pathogenesis domain is also influenced by changes at e2 position 114. mutation of e2 residues asn 62 to asp or lys 159 to glu results in suppression of the attenuated phenotype conferred by a mutation from ...19938345360
post-translational processing and membrane association of the two early endosome-associated rab gtp-binding proteins (rab4 and rab5).the two early endosome-associated rab gtp-binding proteins, rab4 and rab5, are suggested to regulate endocytosis. in this report, we examined post-translational processing and membrane association of the two rab proteins. human rab4 and rab5 were expressed in chicken embryo fibroblasts using a sindbis virus expression vector. cells were labeled with either [35s]methionine or [3h]mevalonolactone. cell lysates were immunoprecipitated with antisera specific for rab4 and rab5, respectively, and anal ...19938346922
sindbis virus membrane fusion is mediated by reduction of glycoprotein disulfide bridges at the cell surface.we have examined the role of thiol-disulfide exchange reactions during the penetration of cells by sindbis virus. the protein-protein association that form the rigid icosahedral lattice of the sindbis virus envelope have been shown to be stabilized by disulfide bridges, and reduction of these critical disulfide bridges during cell penetration may be the mechanism by which the rigid protein lattice is disrupted prior to fusion (r. anthony and d. t. brown, j. virol. 65:1187-1194, 1991; r. anthony, ...19938350409
expression of mouse furin in a chinese hamster cell resistant to pseudomonas exotoxin a and viruses complements the genetic lesion.rpe.40 is a strain of mutated cho-k1 cells with elevated resistance to pseudomonas exotoxin a, sindbis virus, and newcastle disease virus. virus resistance is due to an inability to cleave precursor viral membrane glycoproteins and produce infectious virions. transfection of rpe.40 cells with cdna for mouse furin causes them to lose all resistance and become as sensitive as wild-type cells to the toxin and viruses. transfection of rpe.40 cells with cdna for the related yeast protease kex2 reduce ...19938381410
experimental infection of aedes aegypti (diptera: culicidae) by the oral route with sindbis virus.the infectivity, dissemination, and transmissibility of wild-type sindbis (sin) virus were studied in aedes aegypti (l). there was an initial decline in the viral titer of whole mosquitoes for 3 d after ingestion of virus, followed by a gradual increase to a maximal level by day 6. immunoperoxidase staining of ae. aegypti for viral antigen showed infection of midgut epithelial cells on day 1, of the fat body by day 3, and of the brain by day 4. by day 5, there was infection of the foregut, hindg ...19938384663
purification and characterization of a sindbis virus-induced peptide which stimulates its own production and blocks virus rna synthesis.the antiviral activity described by riedel and brown (j. virol. 29, 51-60) has been purified to homogeneity. a study of the effects of this pure peptide on mosquito cell growth and virus replication has been undertaken. we have found that treatment of noninfected aedes albopictus cells with this antiviral peptide results in a temporary arrest of cell division accompanied by acquisition of virus resistance and the constitutive production of the antiviral protein.19938386889
a second nonstructural protein functions in the regulation of alphavirus negative-strand rna synthesis.previous studies (d.l. sawicki, d. b. barkhimer, s. g. sawicki, c. m. rice, and s. schlesinger, virology 174:43-52, 1990) identified a temperature-sensitive (ts) defect in sindbis virus nonstructural protein 4 (nsp4) that reactivated negative-strand synthesis after its normal cessation at the end of the early phase of replication. we now report identification of two different ts alterations in nsp2 of ala-517 to thr in ts17 or asn-700 to lys in ts133 that also reactivated negative-strand synthes ...19938388513
viral determinants of age-dependent virulence of sindbis virus for mice.many alphaviruses cause more severe disease in young animals than in older animals. the age-dependent resistance to severe disease is determined primarily by maturation of the host, but strains of virus can be selected that overcome the increased resistance of mature animals. sindbis virus (sv) strain ar339 causes fatal encephalitis in newborn mice and nonfatal encephalitis in weanling mice, whereas nsv, a neuroadapted strain of sv, causes fatal encephalitis in weanling as well as newborn mice. ...19938392602
multiple binding sites for cellular proteins in the 3' end of sindbis alphavirus minus-sense rna.the 3' end of sindbis virus minus-sense rna was tested for its ability to bind proteins in mosquito cell extracts, using labeled riboprobes that represented different parts of this region. we found four domains in the first 250 nucleotides that could bind the same 50- and 52-kda proteins, three with high affinity and one with low affinity, whereas tested domains outside this region did not bind these proteins. the first binding domain was found in the first 60 nucleotides, which represents the c ...19938392625
glut4 phosphorylation and inhibition of glucose transport by dibutyryl camp.to investigate the mechanism responsible for the inhibition of glucose transport by dibutyryl camp (bt2camp), two different transporter isoforms (glut1 and glut4) and several glut1/4 chimeric transporters were expressed in chinese hamster ovary (cho) cells by using a sindbis virus expression system. bt2camp inhibited glut4-mediated 2-deoxy[3h]glucose (2dog) uptake by 50% but was without effect on glut1-mediated uptake. when the subcellular distribution of glut4 was assessed by quantitative immun ...19938393869
antiviral melanization reaction of heliothis virescens hemolymph against dna and rna viruses in vitro.1. antiviral activity of heliothis virescens larval hemolymph was determined using a cytotoxicity/virus inhibition test (tcld50) done in vero cell tissue cultures. excellent antiviral activity was found especially against herpes simplex viruses-1 and -2 and also against vesicular stomatitis, parainfluenza-3, coxsackie b3 and sindbis viruses. 2. prolonged incubation of herpes simplex virus-1 and vesicular stomatitis virus with hemolymph was virucidal and greatly reduced infectivity of the two vir ...19938395989
detection of ockelbo virus rna in skin biopsies by polymerase chain reaction.a sensitive assay based on the polymerase chain reaction for the detection of ockelbo virus rna was developed. two primer pairs from the gene coding for the e2 glycoprotein were chosen. by use of a nested strategy for the primers, as few as 1 to 10 pfu could be detected. the amplified products were visualized as bands of appropriate size on ethidium bromide-stained agarose gels. the primer pairs allowed amplification of several ockelbo and sindbis virus isolates but discriminated between these a ...19938396582
phosphorylation and dephosphorylation events play critical roles in sindbis virus maturation.we have examined the effects of various inhibitors of protein kinases and phosphatases on sindbis virus maturation in bhk cells. 2-aminopurine, a nonspecific protein kinase inhibitor, n-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (w-7), a specific inhibitor of calmodulin/ca(2+)-dependent protein kinase, and okadaic acid (oka), a protein phosphatase inhibitor, dose-dependently inhibited sindbis virus maturation. although virus production was inhibited, the membrane glycoprotein ...19938396806
sindbis virus expression vectors: packaging of rna replicons by using defective helper rnas.since the recovery of infectious rna transcripts from full-length cdna clones, alphavirus genome rnas have been engineered to allow expression of heterologous rnas and proteins. the highest levels of expression of heterologous products are achieved when the viral structural genes are replaced by the heterologous coding sequences. such recombinant rnas are self-replicating (replicons) and can be introduced into cells as naked rna, but they require trans complementation to be packaged and released ...19938411346
molecular analysis of neurovirulent strains of sindbis virus that evolve during persistent infection of scid mice.to understand the role of tissue-specific adaptation and antibody-induced selectional pressures in the evolution of neurovirulent viruses, we analyzed three strains of sindbis virus isolated from the brains of persistently infected scid mice and four strains of sindbis virus isolated from the brains of scid mice with viral reactivation following immune serum treatment. for each viral isolate, we tested neurovirulence in weanling balb/c mice and sequenced regions of the e2 and e1 envelope glycopr ...19938411391
three-dimensional structure of a membrane-containing virus.the structure of sindbis virus was determined by electron cryomicroscopy. the virion contains two icosahedral shells of viral-encoded proteins separated by a membrane bilayer of cellular origin. the three-dimensional structure of the ice-embedded intact sindbis virus, reconstructed from electron images, unambiguously shows that proteins in both shells are arranged with the same icosahedral lattice of triangulation number t = 4. these studies also provide structural evidence of contact between th ...19938415660
the distribution of sindbis virus proteins in mosquito cells as determined by immunofluorescence and immunoelectron microscopy.two aedes albopictus (mosquito) subclones, c7-10 and c6/36, were examined by immunofluorescence and immunoelectron microscopy for the distribution of sindbis virus structural and non-structural proteins. both the viral glycoproteins, e1 and e2, and the non-structural proteins, nsp1 and nsp2, were found within vesicles and electron-dense, amorphous matrices associated with sindbis virus infection. the labelling patterns indicated that both replication of viral rna and production of virus particle ...19938429303
transient translocation of the cytoplasmic (endo) domain of a type i membrane glycoprotein into cellular membranes.the e2 glycoprotein of the alphavirus sindbis is a typical type i membrane protein with a single membrane spanning domain and a cytoplasmic tail (endo domain) containing 33 amino acids. the carboxyl terminal domain of the tail has been implicated as (a) attachment site for nucleocapsid protein, and (b) signal sequence for integration of the other alpha-virus membrane proteins 6k and e1. these two functions require that the carboxyl terminus be exposed in the cell cytoplasm (a) and exposed in the ...19938432728
deletion analysis of the capsid protein of sindbis virus: identification of the rna binding region.the capsid protein of sindbis virus has multiple functions in the life cycle of the virus. one essential function is to interact with the genomic rna of the virus to form the nucleocapsid. the experiments described in this article define a region of the protein that is required for binding to sindbis virus rna. the assay we used measured the binding of in vitro-translated proteins to rna on the basis of their migration with the rna during electrophoresis in an agarose gel. binding to rna showed ...19938437233
directed mutagenesis of a sindbis virus pathogenesis site.the e2 glycoprotein gene of sindbis virus contains three neutralizing antigenic sites, and examination of monoclonal antibody (mab) escape mutants of one of these, the e2c site, has suggested an association of the e2c domain with determinants of virulence in neonatal mice. codons associated with the e2c site, e2 62, 96, and 159, were subjected to site-directed mutagenesis generating a library of 25 viable virus mutants containing different amino acids at these loci. the mutants were assessed for ...19938438562
conversion of lytic to persistent alphavirus infection by the bcl-2 cellular oncogene.little is known about virus-host cell interactions that regulate the lytic potential of viruses during productive replication. sindbis virus (sv), a single-stranded positive-sense rna virus in the alphavirus genus (family togaviridae), results in lytic infection in most vertebrate cell lines, but persistent productive infection in post-mitotic neurons. the cellular oncogene bcl-2, which encodes an inner mitochondrial membrane protein of m(r) 26,000 (ref. 2), blocks programmed cell death (apoptos ...19938441470
assembly of functional sindbis virus rna replication complexes: requirement for coexpression of p123 and p34.a vaccinia virus transient expression system was used to determine which of the sindbis virus (sin) proteins and/or polyproteins are necessary for the formation of active replication complexes and, in particular, to analyze the role of nsp4, the putative polymerase, versus p34 in rna replication. we generated vaccinia virus recombinants in which the cdna for the entire sin nonstructural coding region as well as cdna copies of the individual nonstructural proteins (nsps) and several intermediate ...19938445716
roles of nonstructural polyproteins and cleavage products in regulating sindbis virus rna replication and transcription.using vaccinia virus to express sindbis virus (sin) nonstructural proteins (nsps) and template rnas, we showed previously that synthesis of all three viral rnas occurred only during expression of either the entire nonstructural coding region or the polyprotein precursors p123 and p34. in this report, the vaccinia virus system was used to express cleavage-defective polyproteins and nsp4 proteins containing various n-terminal extensions to directly examine the roles of the p123 and p34 polyprotein ...19938445717
refined structure of sindbis virus core protein and comparison with other chymotrypsin-like serine proteinase structures.crystal forms 2 and 3 of sindbis virus core protein have been refined to 2.8 a and 3.0 a resolution, respectively. the three independent molecular copies in the two crystal forms are essentially identical, except for regions where the molecules are involved in different crystal packing interactions. the overall polypeptide backbone fold of sindbis virus core protein is similar to other chymotrypsin-like serine proteinase structures despite a lack of significant sequence homology. detailed analys ...19938450538
potentiation of interferon-alpha in vitro antiviral activity by interferon-gamma is not abrogated by antibody to interferon-gamma.the addition of minute amounts of recombinant interferon-gamma (ifn-gamma) to recombinant ifn-alpha 2 significantly enhances its antiviral activity. although this potentiating action of ifn-gamma is destroyed by treatment with acid, it is not significantly affected by treatment with antibodies to ifn-gamma, suggesting that ifn-gamma molecules can interact with cells to potentiate ifn-alpha activity, even in the presence of neutralizing antibodies. implications of this phenomenon are multifaceted ...19938454911
inhibition of sindbis virus replication by cyclopentenone prostaglandins: a cell-mediated event associated with heat-shock protein synthesis.cyclopentenone prostaglandins (pgs) have been shown to inhibit the replication of several dna and rna viruses. here we report on the effect of prostaglandin a1 (pga1) on the multiplication of a positive strand rna virus, sindbis virus, in vero cells under one-step multiplication conditions. pga1 was found to inhibit sindbis virus production dose-dependently, and virus yield was reduced by more than 90% at the concentration of 8 micrograms/ml, which was non-toxic to the cells and did not inhibit ...19938470883
site-directed mutations in the sindbis virus e2 glycoprotein identify palmitoylation sites and affect virus budding.the assembly and budding of sindbis virus, a prototypic member of the alphavirus subgroup in the family togaviridae, requires a specific interaction between the nucleocapsid core and the membrane-embedded glycoproteins e1 and e2. these glycoproteins are modified posttranslationally by the addition of palmitic acid, and inhibitors of acylation interfere with this budding process (m.j. schlesinger and c. malfer, j. biol. chem. 257:9887-9890, 1982). this report describes the use of site-directed mu ...19938474160
the unusual uva-dependent antiviral properties of the furoisocoumarin, coriandrin.the novel furoisocoumarin, coriandrin, which was found recently to possess an interesting combination of photobiological properties, was investigated for antiviral activity in the presence and absence of uva (long-wavelength ultraviolet radiation). in contrast to results obtained with other antiviral furocoumarins, such as 8-mop (8-methoxypsoralen), coriandrin was much more phototoxic to the rna-virus sindbis virus than to the dna-virus murine cytomegalovirus, although both viruses were substant ...19938475184
[industrial pasteurization of plasma and criteria of quality].the approach followed in the design of a large-scale pasteurization treatment (60 degrees c for 10 hours in the liquid state) of fresh frozen plasma is presented. various aspects thought to influence the viral safety of such a product are discussed. they are based largely upon the fact that, although it is subjected to a specific viral inactivation treatment, this plasma does not benefit from any fractionation steps known to participate in the potential elimination of infectious agents during th ...19938476493
glut-4 nh2 terminus contains a phenylalanine-based targeting motif that regulates intracellular sequestration.expression of chimeras, composed of portions of two different glucose transporter isoforms (glut-1 and glut-4), in cho cells had indicated that the cytoplasmic nh2 terminus of glut-4 contains important targeting information that mediates intracellular sequestration of this isoform (piper, r. c., c. tai, j. w. slot, c. s. hahn, c. m. rice, h. huang, d. e. james. 1992. j. cell biol. 117:729-743). in the present studies, the amino acid constituents of the glut-4 nh2-terminal targeting domain have b ...19938509445
thiol agents and bcl-2 identify an alphavirus-induced apoptotic pathway that requires activation of the transcription factor nf-kappa b.oxidative stress has been proposed as a common mediator of apoptotic death. to investigate further the role of oxidants in this process we have studied the effects of antioxidants on sindbis virus (sv)-induced apoptosis in two cell lines, at-3 (a prostate carcinoma line) and n18 (a neuroblastoma line). the thiol antioxidant, n-acetylcysteine (nac), at concentrations above 30 mm, completely abrogates sv-induced apoptosis in at-3 and n18 cells. the effects of nac cannot be attributed to inhibition ...19958522579
sindbis virus dna-based expression vectors: utility for in vitro and in vivo gene transfer.several dna-based sindbis virus vectors were constructed to investigate the feasibility and potential applications for initiating the virus life cycle in cells transfected directly with plasmid dna. these vectors, when transfected into mammalian cells, have been used to produce virus, to express heterologous genes, and to produce infectious vector particles. this approach involved the conversion of a self-replicating vector rna (replicon) into a layered dna-based expression system. the first lay ...19968523564
[viral validation of the bio-globulin production process].intravenous human immunoglobulin of domestic production was subjected to validation studies. tests were performed in the system of model viruses for pathogenic factors of the b and c types of hepatitis. for simulated immunoglobulin infections two lipid-enveloped viruses were chosen: the first dna virus pseudorabies pr-75 (model for hbv) and the second-rna virus sindbis (model for hcv). the survival of viruses in particular stages of bio-globulin production was checked, showing that pepsin digest ...19958523973
a plasmid-based self-amplifying sindbis virus vector.sindbis virus was used as a self-amplifying eukaryotic expression vector. a recombinant cdna genome of this (+)-strand rna virus was placed under the transcriptional control of a rous sarcoma virus ltr (rsv) promoter. transfection of this plasmid construct into mammalian cell lines (3t3, hepg2, and 293 cells) resulted in expression of the luciferase reporter gene. high-expression levels were also measured after transfection into primary rat myoblasts. in differentiated myotubes, expression level ...19958527474
layered amplification of gene expression with a dna gene delivery system. 19958546403
laboratory transmission of sindbis virus by aedes albopictus, ae. aegypti, and culex pipiens (diptera: culicidae).the susceptibility of aedes albopictus (skuse) for sindbis (sin) virus was examined in the laboratory. ae. albopictus, ae. aegypti (l.), and culex pipiens (l.) became infected with and subsequently transmitted sin virus by bite to chicks after feeding on viremic 1-d-old chicks. after ingesting 10(5.3) plaque-forming units (pfu)/ml, ae. albopictus had the highest transmission rate (30%) of the 3 species. transmission by ae. aegypti was less efficient (7%), whereas none of the cx. pipiens transmit ...19958551504
mosquito homolog of the la autoantigen binds to sindbis virus rna.we have isolated a 50-kda mosquito protein that binds with high affinity to a riboprobe representing the 3' end of the minus strand of sindbis virus rna. the isolated protein has been used to obtain cdna clones encoding this protein that have been sequenced and used to express the protein in large amounts. sequence comparisons make clear that this protein is the mosquito homolog of the la autoantigen. the n-terminal half of the protein shares considerable sequence identity with the human la prot ...19968551578
translation of sindbis virus mrna: analysis of sequences downstream of the initiating aug codon that enhance translation.alphaviruses, particularly sinbis virus and semliki forest virus, are proving to be useful vectors for the expression of heterologous genes. in infected cells, these self-replicating vectors (replicons) transcribe a subgenomic mrna that codes for a heterologous protein instead of the structural proteins. we reported recently that translation of the reporter gene lacz is enhanced 10-fold when the coding sequences of this gene are fused downstream of and in frame with the 5' half of the capsid gen ...19968551579
effect of e2 envelope glycoprotein cytoplasmic domain mutations on sindbis virus pathogenesis.the cytoplasmic domain of the e2 envelope glycoprotein is important in sindbis virus assembly, but little is known about its role in the pathogenesis of sindbis virus encephalitis. to investigate its role in viral pathogenesis, we constructed six recombinant viruses containing site mutations in the e2 cytoplasmic domain, using the neurovirulent background strain, te12. our findings demonstrate that the e2 cytoplasmic domain is a determinant of sindbis virus growth and neurovirulence in suckling ...19968551591
events in the endoplasmic reticulum abrogate the temperature sensitivity of sindbis virus mutant ts23.temperature-sensitive mutations in proteins produced at or heated to a nonpermissive temperature render the proteins defective in some aspect of their maturation into functional entities. the characterization of temperature-sensitive mutations in model proteins, such as virus membrane proteins, has allowed the elucidation of critical events in the maturation of virus membranes as well as in the intracellular folding, processing, and transport of membrane proteins in general. we have used a trans ...19968551635
[concentrate of coagulation factor ix: viral validation of the thermoinactivation process].the coagulation factor ix obtained at the institute of haematology and transfusion in warsaw was subjected to virological validation. two lipide enveloped viruses were used: hsv-1 and sindbis which may be a model for the viruses of b and c types in hepatitis. it was shown that heating of the freeze-drying preparations at 80 degrees c during 72 hrs leads to full inactivation of the added model viruses.19958571744
bax-independent inhibition of apoptosis by bcl-xl.the bcl-2-related protein, bcl-xl, has been shown to block apoptosis induced by a variety of stimuli and to be a stronger protector against apoptosis than bcl-2 under certain circumstances. using site-specific mutagenesis, we show here that the amino-acid residues critical for protection of cells by bcl-xl against sindbis virus-induced apoptosis are clustered within the bcl-2-homology regions 1 and 2 (bh1 and bh2 regions). the residues necessary for bcl-xl function are not identical to those req ...19968596636
inhibition of na+k+atpase activity in membranes of sindbis virus-infected chick cells.alterations in intracellular concentrations of na+ and k+ in sindbis virus-infected cells result largely from inhibition of ouabain-sensitive na+k+atpase (na+ pump) activity. here we report that membrane preparations derived from sindbis virus-infected chick cells exhibit reduced na+k+atpase activity, indicating that limitation of cellular factors is not responsible for inhibition of ion transport. in vitro phosphorylation of the na+k+atpase by [32p]orthophosphate or [gamma 32p]atp is unaltered ...19968607259
mutagenesis of the sindbis virus nsp1 protein: effects on methyltransferase activity and viral infectivity.it has been suggested that four amino acids which are absolutely conserved in th nsp1 nonstructural proteins encoded by togaviruses and in the homologous proteins encoded by plant viruses in the sindbis virus (sv) superfamily may constitute a "methyltransferase motif." in the sindbis virus nsp1 protein (540 amino acids) these four amino acids are represented by his39, arg91, asp94, and tyr249. earlier, in assays of methyltransferase (mtase) activity generated in sv-infected cells, we had shown t ...19968610444
regulation of lymphocyte homing into the brain during viral encephalitis at various stages of infection.the passage of circulating lymphocytes into the central nervous system (cns) during acute viral encephalitis was studied in vivo using fluorescently labeled cells inoculated into sindbis virus (sv)-infected mice. donor lymphocytes were detected in the brains of recipient animals when mononuclear cells were isolated from the cns and screened by flow cytometry. the magnitude of this accumulation related to the duration of encephalitis in recipient mice and to the activation state of the inoculated ...19968621923
assembly of the sindbis virus spike protein complex.the sindbis virus glycoproteins e1 and e2 are organized into 80 trimers of heterodimers within the virus envelope. using pulse-chase protocols and chemical crosslinkers, we have found that e1 and e2 precursor, pe2, rapidly assemble into heterodimers and then into trimers of heterodimers after translocation into the endoplasmic reticulum. e1 folds into its mature conformation within the endoplasmic reticulum via at least three intermediates differing in the configurations of their disulfide bonds ...19968623521
alphavirus-induced apoptosis in mouse brains correlates with neurovirulence.sindbis virus induces apoptotic cell death in cultured cell lines, raising the possibility that apoptosis of infected neurons and other target cells in vivo may contribute to the resulting disease and mortality. to investigate the role of apoptosis in sindbis virus pathogenesis, infected mouse brains were assayed by the in situ terminal deoxynucleotidyltransferase-mediated dutp nick end-labeling technique and for dna ladder formation. infection with recombinant sindbis virus strain 633 resulted ...19968627707
deduced consensus sequence of sindbis virus strain ar339: mutations contained in laboratory strains which affect cell culture and in vivo phenotypes.the consensus sequence of the sindbis virus ar339 isolate, the prototype alphavirus, has been deduced. the results presented here suggest (i) that a substantial proportion of the sequence divergence evident between the consensus sequence and sequences of laboratory strains of ar339 has resulted from selection for efficient growth in cell culture, (ii) that many of these changes affect the virulence of the virus in animal models, and (iii) that such modified genetic backgrounds present in laborat ...19968627724
differential processing of sindbis virus glycoprotein pe2 in cultured vertebrate and arthropod cells.a step in the maturation of sindbis virus glycoproteins is the cleavage of the precursor glycoprotein pe2 into e3 and e2 by furin or a furin-like host cell protease. the results presented here suggest that pe2 cleavage is an obligatory event for sindbis virus maturation in c6/36 cells and demonstrate that certain mutants display a cell-specific pe2 cleavage phenotype. we previously have described sindbis virus variants which fail to cleave pe2 because of incorporation of a signal for n-linked gl ...19968627739
sindbis virus rna-negative mutants that fail to convert from minus-strand to plus-strand synthesis: role of the nsp2 protein.we identified mutations in the gene for nsp2, a nonstructural protein of the alphavirus sindbis virus, that appear to block the conversion of the initial, short-lived minus-strand replicase complex (rcinitial) into mature, stable forms that are replicase and transcriptase complexes (rcstable), producing 49s genome or 26s mrna. base changes at nucleotide (nt) 2166 (g-->a, predicting a change of glu-163-->lys), at nt 2502 (g-->a, predicting a change of val-275-->ile), and at nt 2926 (c-->u, predic ...19968627744
identification of a region in the sindbis virus nucleocapsid protein that is involved in specificity of rna encapsidation.the specific encapsidation of genomic rna by an alphavirus requires recognition of the viral rna by the nucleocapsid protein. in an effort to identify individual residues of the sindbis virus nucleocapsid protein which are essential for this recognition event, a molecular genetic analysis of a domain of the protein previously suggested to be involved in rna binding in vitro was undertaken. the experiments presented describe the generation of a panel of viruses which contain mutations in residues ...19968627749
dengue hemorrhagic fever. 19968629013
genetically engineered resistance to dengue-2 virus transmission in mosquitoes.the control of arthropod-borne virus diseases such as dengue may ultimately require the genetic manipulation of mosquito vectors to disrupt virus transmission to human populations. to reduce the ability of mosquitoes to transmit dengue viruses, a recombinant sindbis virus was used to transduce female aedes aegypti with a 567-base antisense rna targeted to the premembrane coding region of dengue type 2 (den-2) virus. the transduced mosquitoes were unable to support replication of den-2 virus in t ...19968629025
molecularly engineered resistance to california serogroup virus replication in mosquito cells and mosquitoes.introduction of genetic elements derived from a viral pathogen's genome may be used to reduce the vectorial capacity of mosquitoes for that virus. a double subgenomic sindbis virus expression system was utilized to transcribe sequences of lacrosse (lac) virus small (s) or medium (m) segment rna in sense or antisense orientation; wild-type sindbis and lacrosse viruses have single-stranded rna genomes, the former being positive sense and the latter being negative sense. recombinant viruses were ge ...19968633038
pathogen-derived resistance to dengue type 2 virus in mosquito cells by expression of the premembrane coding region of the viral genome.the full-length premembrane (prm) coding region of the dengue virus type 2 (den-2; jamaica) genome was expressed in c6/36 (aedes albopictus) cells in either the sense or the antisense orientation from a double subgenomic sindbis (dssin) virus. northern (rna) blot analysis confirmed the expression of sense or antisense den-2 prm rna in infected c6/36 cells. prm protein was demonstrated in cells infected with dssin virus expressing den-2 sense rnas by an immunofluorescence assay. c6/36 cells were ...19968642634
temporal changes in chromatin, intracellular calcium, and poly(adp-ribose) polymerase during sindbis virus-induced apoptosis of neuroblastoma cells.sindbis virus (sv) induces apoptosis in many vertebrate cells, but the mechanism is unknown. to gain insight into this mechanism, the nature and time course of intracellular changes related to programmed cell death were studied in sv-infected mouse neuroblastoma cells. new virus production began at 5 h after infection and reach a peak at 12 h. hoechst 33342 staining of dna analyzed by flow cytometry demonstrated changes in chromatin beginning 6 h after infection. these chromatin changes were cel ...19968642645
bc1-2 protects mice against fatal alphavirus encephalitis.virus-induced apoptosis has been well characterized in vitro, but the role of apoptosis in viral pathogenesis is not well understood. the suicide of a cell in response to viral infection is postulated to be an important host defense for the organism, leading to a reduction in its total viral burden. however, virus-induced death of nonregenerating cells in the central nervous system may be detrimental to the host. therefore, to investigate the role of apoptosis in the pathogenesis of fatal enceph ...19968643485
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