mosquito-borne arboviruses in arctic america.mosquito-borne arboviruses are prevalent throughout subarctic regions of canada and alaska, principally in the boreal forest extending between latitudes 53 and 66 degrees n, but they have been identified in tundra regions as far north as 70 degrees n. all mosquito-borne agents have been bunyaviruses, comprising principally the snowshoe hare subtype of california encephalitis (ce) virus, but also northway virus. mosquito vectors comprise several aedes species and culiseta inornata, all of which h ...19751602
buoyant density of some togaviruses in sucrose density gradient and capacity of their haemagglutinin fractions to interact with antibody.the buoyant densities of western equine encephalomyelitis virus (an alphavirus) and tick-borne encephalitis (tbe) virus (a flavivirus) antigens prepared by different methods were studied. sucrose density centrifugation revealed a heterogeneity in the density of the virions. the sedimentation pattern and height of peaks of the haemagglutinating activities and infectivity, other conditions being equal, depended both on the virus species and properties of its strains and on the mode of preparation ...197611662
ord river arboviruses--isolations from hundred and thirty presumptive viruses have been isolated from 485 pools made from 23,872 mosquitoes collected in the ord river area of north-west australia. one hundred and eleven of the virus isolates isolates came from pools of culex annulirostis, the dominant mosquito species caught in the vicinity of kununurra. forty-five of the viruses pathogenic for newborn mice have been further characterized-19 as flaviviruses, 1 alphavirus, 9 koongol, 1 mapputta and 15 non-haemagglutinating viruses ...197614613
plaque formation by alphavirus (getah) in culex mosquito cells.plaques were formed by getah virus (an alphavirus) which had been grown in bhk cells and passaged once in culex cells before inoculation of culex cell cultures. plaques were not produced either by getah or japanese encephalitis (je) viruses which had been passaged only in bhk cells. plaque counts in culex cell monolayers were almost the same as in bhk cells.197717288
chromatographic separations of alphavirus strains by hydroxylapatite.hydroxylapatite column chromatography methods were developed to characterize selected alphavirus populations. different conditions of ph and phosphate molarity were required to obtain satisfactory elution profiles and separations for western equine encephalomyelitis virus strains, compared with eastern equine encephalomyelitis virus and semliki forest virus strains. raising the ph of the buffers effected earlier elutions of all viruses. selection of phosphate gradients with more gentle slopes an ...197720452
isolation of sindbis (alphavirus) and leanyer viruses from mosquitoes collected in the northern territory of australia, 1974.mosquitoes collected near darwin, northern territory, in 1974 yielded two virus strains. one was identified as sindbis virus, not previously isolated from the northern territory. the other is antigenically distinct from viruses previously isolated from arthropods in australia, and the name "leanyer" is proposed for it. its properties suggest that it may be a togavirus serologically unrelated to available alphaviruses and flaviviruses.197723749
[comparative analysis of the morphogenesis of the getah virus in cell cultures of vertebrates and mosquitoes].reproduction of getah virus (the genus alphavirus) in piglet kidney (pk) and a. aegypti mosquito cell cultures was studied morphologically. inoculation of pk cells resulted in the development of a lytic infection. virus morphogenesis in these cells showed the features known for other alphaviruses. in mosquito cell cultures persistent infection developed which was not accompanied by any marked changes in morphology or proliferative activity of the culture. all the morphological and cytochemical d ...197934927
hemolytic activity of a togavirus, getah.a purified toga-alphavirus, getah (get), showed optimal hemolytic activity for one-day-old chick red blood cells when incubated at 37 c for 120 min at ph 6.2. experimental data obtained from various angles, such as ph dependency, inhibition by virus-specific antiserum and by concanavalin a, indicated that the hemolysis was a property of the virus particle itself. although the mechanism of hemolysis by togaviruses has not been known, our results indicated that viral lipids may participate in this ...197937415
characterization of two chikungunya virus variants.the stability of virulence and plaque size of two variants of chikungunya virus (genus alphavirus) were examined. mouse pathogenicity did not coincide with infective virus levels in the brain. an increase in the average survival times of mice receiving a lethal dose of the variant which allowed prolonged survival at high doses and harvested late after infection was observed. studies in vero cells suggested that the number of infective virus particles produced per cell was lower with the small pl ...197939435
h-2-linked control of cytotoxic t-cell responsiveness to alphavirus infection. presence of h-2dk during differentiation and stimulation converts stem cells of low responder genotype to t cells of responder phenotype.secondary tc cells generated against sindbis virus (sin) are restricted to dk. all other h-2k or d regions tested show low specific responsiveness. f1 hybrids between low and high responders show dominance of responsiveness but lack complementation. when balb/c (kdiddd) low responder fetal liver stem cells were allowed to mature in irradiated high responder recipients c3h.oh (kdiddk) a response to dk plus sin could be generated with tc cells of balb/c origin. this result, together with the failu ...1979107264
dimethyl sulfoxide enhancement of phlebotomus fever virus plaque formation.dimethyl sulfoxide (dmso)incorporated into an agar overlay containing deae-dextran enhanced plaque formation in vero cells by naples sandfly fever virus passaged in mouse brain or vero cell cultures. no plaques were visible when dmso was used without the deae-dextran, some plaques were rarely visible (less than 0.5mm) when deae-dextran was used without the dmso, and up to 10-fold more plaques were clearly visible (0.5-1.5 mm) when both chemicals were used. the combined enhancing effect of dmso a ...1979223461
persistence in humans of antibody after immunization with four alphavirus vaccines.immunization with attenuated vee virus vaccine resulted in persistence of neutralizing antibody for 12 years. immunization with inactivated wee vaccine converted 83% of the subjects, killed eee vaccine converted 27% and killed chikungunya vaccine induced no significant titers. antibody formed as a result of immunization with inactivated vaccines was of short duration, i.e. less than 1 year. attenuated vee was responsible for some heterologous antibody rises to the other three alphaviruses. among ...1979233418
[serological survey on the prevalence of arboviruses in man in forest and periforest environments of the region of lobaye (central african republic)]. 1979233526
cross-reactive cytotoxic t cells to alphavirus infection.secondary tc cells immune to alphaviruses (beb, sin and sfv) cross-react between serologically defined subgroups at the level of target lysis and at the level of induction of response. despite this apparently complete tc cell cross-reactivity between beb, sin and sfv, antisera raised against beb and sin showed virus specificity in their ability to block tc cell-mediated lysis of alphavirus-infected targets. this result suggests that tc cells recognize the same viral antigen molecule as antibodie ...1979316916
two small virus-specific polypeptides are produced during infection with sindbis virus.we have identified and characterized two small virus-specific polypeptides which are produced during infection of cells with sindbis virus, but which are not incorporated into the mature virion. the larger of these is a glycoprotein with an approximate molecular weight of 9,800 and is found predominantly in the medium of infected cells. three independent lines of evidence demonstrate conclusively that this 9,800-dalton glycoprotein is produced during the proteolytic conversion of the precursor p ...1979448798
[accelerated method of determining the antiviral activity of interferon inducers in experimental infection].by the example of trials of two typical interferon inducers: a double-stranded complex of synthetic polyribonucleotides poly (i).poly (c) and polyacrylic acid the use of the proposed rapid method for the determination of the antiviral activity of interferon inducers in an experimental infection of mice with an alphavirus is described. the method permits to perform a statistically treated evaluation of the antiviral effect of a group of preparations within 96 hours. the mean standard error of the ...1979462928
proteins specified by togaviruses in infected aedes albopictus (singh) mosquito cells.yields of greater than 10(7) p.f.u./ml at 28 or 37 degrees c of the alphavirus sindbis and the flavivirus kunjin were obtained in the aedes albopictus (singh) cell line, the latent periods being 4 to 6 and 10 to 12 h, respectively. despite a high background of host protein synthesis, virtually all the virus-specified proteins of the flaviviruses kunjin, dengue-2 and japanese encephalitis were labelled and resolved by slab gel electrophoresis of infected and uninfected cell proteins. in contrast, ...1979479844
heterologous interference in aedes albopictus cells infected with alphaviruses.maximum amounts of 42s and 26s single-stranded viral rna and viral structural proteins were synthesized in aedes albopictus cells at 24 h after sindbis virus infection. thereafter, viral rna and protein syntheses were inhibited. by 3 days postinfection, only small quantities of 42s rna and no detectable 26s rna or structural proteins were synthesized in infected cells. superinfection of a. albopictus cells 3 days after sindbis virus infection with sindbis, semliki forest, una, or chikungunya alp ...1979480461
[origin and formation of different types of vacuoles induced by the multiplication of the alphavirus sindbis virus in various cell systems].spherule-containing vacuoles and nucleocapsid-bearing vacuoles (cytopathic vacuoles types 1 and 2 respectively of grimley et al. 1968) induced by alphavirus sindbis were studied in brains from newborn mice, chicken embryo fibroblasts, and two lines of tumoral glial cells from muridae. endoplasmic reticulum (er) elements and finely granular electron-dense material also seen in contact with nucleocapsids seemed to be involved in the formation of the classical single-membrane spherule-containing va ...1979534962
radioimmunoassay for quantitation of antibodies to alphaviruses with staphylococcal protein a.a radioimmunoassay (ria) procedure is described for measuring antibodies to alphaviruses in human and other mammalian sera. the test employed protein abearing staphylococcus aureus as a solid-phase immunoadsorbent for (3)h-labeled viruses complexed with immunoglobulin g. using antibodies produced in humans and guinea pigs, the ria procedure clearly differentiated among antibodies to venezuelan, western, and eastern equine encephalomyelitis viruses. sensitivity of the ria depended on the concentr ...1978566768
togaviridae.the family togaviridae is described; it contains four genera--alphavirus, flavivirus, pestivirus and rubivirus--and additional members. the main characteristics of the family are as follows: single-stranded, linear rna, molecular weight about 4 x 10(6). virions have isometric nucleocapsids surrounded by a lipoprotein envelope containing host cell lipid and virus-specified polypeptides including one or more glycopeptides. virions yield infectious rna. there are at least 80 members; all the alphav ...1978618831
identification of saint louis encephalitis virus mrna.saint louis encephalitis (sle) virus-specific rna was recovered from infected hela cells by sodium dodecyl sulfate (sds)-phenol-chloroform extraction, and the molecular species were resolved by sds-sucrose gradient centrifugation and agarose gel electrophoresis. sucrose gradient centrifugation revealed the presence of a 45s species, minor 20 to 30s heterogeneous species, and an 8 to 10 s rna species in the cytoplasmic extract. analysis of the same samples by electrophoresis on agarose gels, unde ...1978625082
synthesis of alphavirus-specified rna.uv irradiation of chicken fibroblasts infected with semliki forest or sindbis virus has been used to investigate the mechanism of synthesis of 42s and 26s rna, the major plus-strand virus-specified rnas formed during the multiplication of standard virus particles. from an analysis of the kinetics of uv inactivation of the synthesis of these two rnas, we conclude (i) that 26s rna is formed by internal transcriptive initiation from a point about two-thirds of the way from the 3' end of the 42s neg ...1978625087
use of semliki forest virus to identify lipid-mediated antiviral activity and anti-alphavirus immunoglobulin a in human a simple and reliable assay system, semliki forest virus (sfv) was used to detect the activity of antiviral factors in human milk. fractionation of the milk showed that a heat-stable, lipid-associated activity and an immunoglobulin-associated activity were present, either singly or together, in 85% of the human milk samples tested. cow and synthetic milk showed neither activity. extraction of the neutral milk lipids allowed the antiviral to be located with the monoglyceride and free fatty ac ...1978631878
detection of antibodies to alphaviruses and flaviviruses in some migratory birds of the danube are reported on the presence of antibodies to some group a(alphavirus) b(flavivirus) arboviruses in 8 species of migratory birds (ardea cinerea, plegadis falcinellus, anas querquedula, anser albifrons, gavia arctica, fulica atra, larus minutes and and phalacrocorax corbo) of the danube delta.1978676070
necrotizing myocarditis in mice infected with western equine encephalitis virus: clinical, electrocardiographic, and histopathologic correlations.western equine encephalitis (wee) virus was found in myocardial tissue of adult mice during the first five days after inoculation of the virus, with a peak titer (5.0 log plaque-forming units/g) at 24 hr. light microscopy revealed a multifocal necrotizing myocarditis with a prominent inflammatory response and hyaline and granular degeneration of myofibers. electron microscopy showed cytoplasmic viral nucleoids and budding and free mature wee viral particles. serial electrocardiograms showed the ...1978681791
isolation of chikungunya virus contaminating an aedes albopictus cell aedes albopictus cell line was found contaminated with structures morphologically compatible with an alphavirus. rapid isolation of a cytopathic virus was effected by combining sonication, concentration with aquacide ii-r, rate zonal sedimentation and subsequent plating of fractions on vero cells under agar overlay. the virus caused neithedeath nor disease on inoculation into infant and adult mice. it produced a c.p.e. in vero and bhk 21 cells, and multiplied in singh's aedes aegypti cells. t ...1975806659
[comparative studies of two alphavirus by macroplaque assays and by a fluorescent focus method in vero cell lines (author's transl)].immune anti-sindbis and anti-chikungunya ascitic fluids have been titrated by the classic way of plaque reduction and by a quick fluorescent focus method using an indirect staining. the results are comparable, allowing to consider the use of this quick and inexpensive technic for counting-assays by neutralization.1976828464
antibody studies in ponies vaccinated with venezuelan equine encephalomyelitis (strain tc-83) and other alphavirus vaccines.serologic studies in 24 ponies indicated that prevaccination antibodies to venezuelan equine encephalomyelitis (vee) virus (strain tc-83) had no influence on hemagglutination-inhibition (hi) antibody stimulation by western equine encephalomyelitis (wee) or eastern equine encephalomyelits (eee)-wee vaccines. however, studies of the effects of vee neutralizing antibodies on neutralizing antibody stimulation by the heterologous alphavirus vaccines were inconclusive. the vee, wee, and eee antibody r ...1977851275
immune electron microscopy of arboviruses.representative members of four arbovirus taxons were studied by immune electron microscopy (iem) in an attempt to determine whether the technique can be applied to the specific identification of arboviruses. alphavirus, flavivirus, bunyavirus, and rhabdovirus antigens were prepared by propagation in tissue culture. the viruses were used to titrate homologous antibody and test heterologous antibody in the iem test. specific clumping together with visualization of antibody attachment was observed ...1977889020
evaluation of vascular clearance as a marker for virulence of alphaviruses: disassociation of rapid clearance with low virulence of venezuelan encephalitis virus strains in guinea pigs.the concept that relates low virulence of certain alphaviruses to low viremia and efficient vascular clearance of virus was tested in guinea pigs. previously published studies with hamsters suggested that virulent strains maintain high viremias primarily because they are cleared inefficiently from the blood. in the present study, with guinea pigs, six of six virulent strains of venezuelan encephalitis virus were cleared inefficiently, whereas three of six nonlethal or benign virus strains were c ...1977892910
[reproduction and interferogenic activity of togaviruses].a comparative study of the correlation between reproduction and the interferon-inducing activity of viruses in chick embryo fibroblast cultures was carried out with members of different groups of togaviruses: alphavirus (venezuelan equin encephalomyelitis viru, vee) and flavivirus (saint louis encephalitis virus, sle). the correspondence between cycles of accumulation of intracellular and extracellular viruses and the dynamics of interferon production the synthesis of which began early in the st ...1977898898
[interrelationship of alphavirus-venezuelan equine encephalomyelitis virus reproduction and oncornavirus type d production with the metabolism of the infected cells].a comparative study of the reproduction of an alphavirus. venezuelan equine encephalomyelitis virus (vee), in chick embryo fibroblasts (cef) and oncornavirus type d (ov-d) produced spontaneously by human continuous cells (hep-2) was carried out. the differential index of reproduction of both viruses was the yield of rna-containing virus structures released from the cells. for vee this index increased in the course of infection 100-150-fold. for ov-d the index changed little during long-term cult ...1977910441
proposed nomenclature for alphavirus polypeptides. 1976950561
replication of semliki forest virus.replication of semliki forest virus, a typical alphavirus, takes place in the cytoplasm of many eukaryotic cells. the virus genome, the 42 s rna, directs the synthesis of at least two rna-dependent rna polymerases. by the aid of these enzymes complementary 45 s rna is synthesized; it serves as a template for the synthesis of positive rna strands with sedimentation values of 45 s and 26 s. in bhk cells close to 200,000 molecules of each rna species are produced per cell. both 26 s and 42 s rnas a ...19751107685
processing of alphavirus-specific proteins in infected cells.the rna of the alphaviruses contains the genetic information for both the non-structural and the structural polypeptides. the former are contained in the initial two-thirds of the sequence (from the 5'-terminus) and are read directly from the virus particle rna, but whether post-translational cleavage is involved or not is not known. the genes for the structural polypeptides are in the final one-third of the genome, and are probably not read directly but are transcribed selectively to produce a ...19751107686
the distribution and prevalence of group a arbovirus neutralizing antibodies among human populations in southeast asia and the pacific islands.plaque reduction neutralization tests, using five group a arboviruses (chikungunya, ross river, getah, bebaru and sindbis), were done on sera from human populations in 44 southeast asia and pacific island localities. specificity of the plaque neutralization test was determined by examining convalescent sera from patients with known alphavirus infections. chikungunya-specific neutralizing antibodies were demonstrated in sera of persons living in south vietnam, northern malaysia, indonesia (kalima ...19751155702
defective particles in alphavirus infections.this article summarizes our studies with defective-interfering particles of sindbis virus obtained by high multiplicity passaging of the virus in bhk cells. cells infected with these defective passages accumulate a species of rna (20s) at the expense of 26s rna--the mrna coding for the viral structural proteins. although the structure of the rna in defective particles remains undefined, our studies of replicative forms and replicative intermediates suggest that it is larger than the intracellula ...19751207189
the basis of arbovirus classification.the biologically defined set of arboviruses contains well over 300 separate viruses which have been subdivided into some 40 serological groups on the basis of antigenic cross-reactivity. more than three quarters of all arboviruses can now bw placed into one of the following five major taxonomic genera based upon the fundamental properties of the virion: alphavirus, flavivirus, orbivirus, rhadovirus, bunyavirus. there are 20 alphaviruses, representing serological group a, and 57 flaviviruses in s ...19751207193
[arbovirus antibodies in wild game caught in moravia].the hit method was used to examine blood serums of the game in moravia (roebuck, red deer, fallow deer, mouflon, wild boar, brown hare) for the presence of antibodies to arboviruses of these groups: alphavirus (sindbis-sin), flavivirus (west nile-wn), tick-borne encephalitis (tbe) and bunyamwera (tahyna-tah, calovo-cvo). antibodies to all viruses were detected, and namely in these frequencies: sin 0.9%, wn 16.9%, tah 41.5%, cvo 23.1% and tbe 8.5%.19921292172
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
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
antibodies to ockelbo virus in three orders of birds (anseriformes, galliformes and passeriformes) in sweden.sera from 324 birds collected in an ockelbo virus disease endemic area in central sweden were examined for the presence of specific antibodies to ockelbo virus by a plaque reduction neutralization test. birds examined belonged to the orders anseriformes (n = 207), galliformes (n = 66) and passeriformes (n = 51). ockelbo virus neutralizing antibodies were detected in 26 (8%) of the specimens, including species from each of the three orders tested. specific antibodies found in caged birds and in 6 ...19921312646
translation of potato virus s rna in vitro: evidence of protein processing.rna from potato virus s (pvs), a member of the carlavirus group, was translated in vitro in rabbit reticulocyte lysate. time-course experiments revealed the largest product of mr 190 kd, decreasing in intensity after 60-min incubations, correlating with the accumulation of a 150-kd peptide. this apparent processing could be blocked by the addition of the amino-acid analogues p-fluorophenylalanine and l-canavanine for phenylalanine and arginine, respectively. l-canavanine also appeared to specifi ...19921312755
susceptibility of selected strains of aedes aegypti and aedes albopictus (diptera: culicidae) to chikungunya virus.the relative susceptibility of selected strains of aedes aegypti (l.) and aedes albopictus (skuse) fed on a viremic monkey to infection with chikungunya virus was determined. infection rates were consistently higher in 10 strains of ae. albopictus tested than in 7 strains of ae. aegypti tested, regardless of the geographic location from which the strains originated or the dose of virus ingested. similarly, virus dissemination rates were higher in the ae. albopictus strains compared with the ae. ...19921313111
genetic diversity and slow rates of evolution in new world alphaviruses. 19921318187
neuronal cell cultures as a model for assessing neurotoxicity induced by encephalitic viruses.primary dispersed and organotypic cultures were prepared from selected brain areas and spinal cords of rat (sprague-dawley) and mouse (sjl/ola(f) ness-ziona) fetuses and neonates. following fiber regeneration, synapse formation and myelination, cultures were infected with one of the following viruses: rabies cvs-21 strain, sindbis alphavirus, west-nile flavivirus and theiler murine encephalomyelitis virus. light and electron microscopical studies showed clear differences in the target cells for ...19921324447
igg subclass responses in brain and serum in semliki forest virus demyelinating encephalitis.the response of igg subclasses within the central nervous system (cns) of the mouse to semliki forest virus (sfv), an alphavirus associated with meningoencephalitis and primary immune mediated demyelination, has been measured using immunocytochemistry. the subclass response in serum has been assessed using virus specific enzyme linked immunosorbent assays. in the cns igg1 was poorly represented throughout the sampling period of 28 days with a maximum of 3% of the total number of positive cells o ...19921326725
role of cell surface spikes in alphavirus budding.alphaviruses mature by budding at cell surfaces. according to a prevailing hypothesis, the viral membrane protein, which is a heterodimeric protein unit, is transported to the plasma membrane (pm), where it awaits binding to the viral nucleocapsid (nc). this hypothesis predicts that the viral membrane protein heterodimers accumulate at the cell surface when expressed in the absence of ncs. we have tested this prediction by analyzing the spike protein expression phenotype of a semliki forest viru ...19921331511
alphavirus assembly and entry: role of the cytoplasmic tail of the e1 spike subunit.the alphavirus semliki forest virus (sfv) matures by budding at the cell surface. this process is driven by interactions of its membrane protein heterodimer e2-e1 and the nucleocapsid. the virus penetrates into new cells by an e1-mediated membrane fusion event. the e1 subunit has a short, strongly positively charged cytoplasmic tail peptide (arg-arg) which is very conserved among different alphavirus e1 proteins. in this work, we have used in vitro mutagenesis of a full-size cdna clone of sfv to ...19921331539
arboviruses as aetiological agents of encephalitis in the people's republic of china.a serological study was undertaken to determine the role of arboviruses as etiological agents of encephalitis in the people's republic of china (prc). paired sera were collected during mosquito seasons in 1988-1990 from 614 patients with possible viral encephalitis in 15 regions of prc and tested for haemagglutination inhibiting antibodies to selected arboviruses. seroconversions were documented to alphavirus and flavivirus antigens in 13.0 and 18.7% of patients respectively in most of the study ...19921332220
[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
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
antiviral (rna) activity of selected amaryllidaceae isoquinoline constituents and synthesis of related substances.a series of 23 amaryllidaceae isoquinoline alkaloids and related synthetic analogues were isolated or synthesized and subsequently evaluated in cell culture against the rna-containing flaviviruses (japanese encephalitis, yellow fever, and dengue viruses), bunyaviruses (punta toro, sandfly fever, and rift valley fever viruses), alphavirus (venezuelan equine encephalomyelitis virus), lentivirus (human immunodeficiency virus-type 1) and the dna-containing vaccinia virus. narciclasine [1], lycoricid ...19921336040
isolation of getah virus from mosquitos collected on hainan island, china, and results of a isolate of getah virus was obtained from culex mosquitos collected in mao'an village, baoting county, hainan province, china, in 1964. the virus (strain m-1) replicated in laboratory-bred aedes aegypti and cx. fatigans (= quinquefasciatus), and was transmitted by laboratory-bred ae. albopictus to healthy newborn albino mice. skeletal muscles of newborn albino mice experimentally infected with the virus showed degeneration, atrophy, necrosis, and inflammatory changes of muscle fibers. antibody ...19921338481
arbovirus isolations from mosquitoes collected during 1988 in the senegal river basin.during august and september 1988, we collected adult mosquitoes from 14 locations in the senegal river basin to search for evidence of rift valley fever (rvf) viral activity one year after the 1987 outbreak, which occurred along the senegal-mauritania border. more than 62,000 specimens representing 18 species in seven genera were collected with carbon dioxide-baited, solid-state army miniature light traps and sheep-baited traps. twenty virus isolations from culex, aedes, and anopheles mosquitoes ...19921361722
examples of expression systems based on animal rna viruses: alphaviruses and influenza virus.successful recovery of rna viruses and functional rna replicons from cdna has greatly facilitated molecular genetic analyses of viral proteins and cis-regulatory elements. this technology allows the use of rna virus replication machinery to express heterologous sequences. both positive-strand and negative-strand animal rna viruses have been engineered to produce chimeric viruses expressing protective epitopes from other pathogens and for transient expression of heterologous sequences.19921369402
characterization of a major neutralization domain of ross river virus using anti-viral and anti-peptide antibodies.the e2 glycoprotein of the alphavirus ross river virus (rrv) contains three defined neutralization epitopes (a, b1 and b2) with determinants located between amino acids 216 and 251 in the linear sequence (vrati et al., 1988, virology 162, 346-353). the antigenic structure of this region has been examined using hyperimmune mouse antiserum against rrv and antiserum against four synthetic peptides representing linear amino acid sequences in the neutralization region of e2. in plaque reduction neutr ...19921371026
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
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
experimental transmission of venezuelan equine encephalomyelitis virus by a strain of aedes albopictus (diptera: culicidae) from new orleans, louisiana.experimental studies were undertaken to ascertain the vector competence of a strain of aedes albopictus (skuse) collected in new orleans, la, (gentilly strain) for an epizootic (trinidad donkey) strain of venezuelan equine encephalomyelitis (vee) virus. this strain of ae. albopictus was significantly more susceptible to infection with vee virus than were any of the four strains tested previously, including two from north america and two from south america. likewise, dissemination (148 of 180) (8 ...19921404258
membrane fusion of semliki forest virus involves homotrimers of the fusion protein.infection of cells with enveloped viruses is accomplished through membrane fusion. the binding and fusion processes are mediated by the spike proteins in the envelope of the virus particle and usually involve a series of conformational changes in these proteins. we have studied the low-ph-mediated fusion process of the alphavirus semliki forest virus (sfv). the spike protein of sfv is composed of three copies of the protein heterodimer e2e1. this structure is resistant to solubilization in mild ...19921433520
synthesis and antiviral evaluation of n-carboxamidine-substituted analogues of 1-beta-d-ribofuranosyl-1,2,4-triazole-3-carboxamidine hydrochloride.ten, hitherto unreported, analogues of 1-beta-d-ribofuranosyl-1,2,4-triazole-3-carboxamidine hydrochloride (2a, ribamidine) and methyl carboximidate 5 have been synthesized. these include the n-cyano (2b), n-alkyl (2c-e), n-amino acid (2f-h), n,n'-disubstituted (6, 7a,b), and the n-methylated carboxamide (1f) analogues of ribavirin. in addition, a new facile synthesis of carboxamidine 2a was also developed. all compounds were evaluated for biological activity against the following rna viruses: p ...19921507208
characterization of swine infertility and respiratory syndrome (sirs) virus (isolate atcc vr-2332).the characterization of an isolate of swine infertility and respiratory syndrome (sirs) virus (atcc vr-2332) is reported. a commercial cell line (cl2621) was used for the propagation of the virus for all assays. laboratory studies indicate that this isolate is a fastidious, nonhemagglutinating, enveloped rna virus. cesium chloride-purified virions visualized by electron microscopy were spherical particles with an average diameter of 62 nm (range: 48-83 nm) and a 25-30 nm core surrounded by an en ...19921616976
spike protein-nucleocapsid interactions drive the budding of alphaviruses.semliki forest virus (sfv) particles are released from infected cells by budding of nucleocapsids through plasma membrane regions that are modified by virus spike proteins. the budding process was studied with recombinant sfv genomes which lacked the nucleocapsid protein gene or, alternatively, the spike genes. no subviral particles were released from cells which expressed only the nucleocapsid protein or the spike proteins. virus release was found to be strictly dependent on the coexpression of ...19921629953
alphavirus spike-nucleocapsid interaction and network antibodies.vaux et al. (d. j. t. vaux, a. helenius, and i. mellman, nature (london) 336:36-42, 1988) recently reported the production of network antibodies that were suggested to have reconstructed a specific interaction between the nucleocapsid of semliki forest virus and the cytoplasmic tail of the viral e2 spike protein. the f13 anti-idiotype antibody, which was raised against anti-e2 tail antibodies, was claimed to recognize the virus nucleocapsid. in this report, we have used recombinant sfv viruses t ...19921629965
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
laboratory studies of a brazilian strain of aedes albopictus as a potential vector of mayaro and oropouche viruses.the vector efficiency of colonized aedes albopictus from brazil was assessed for mayaro (may) and oropouche (oro) viruses. female mosquitoes, 3-4 days old, were fed on a may-infected hamster with a viremia level of 5.3 log10 vero cell plaque-forming units (pfu) of virus/ml or an oro-infected hamster circulating 7.3 log10 pfu/ml. mayaro infection rates among fed mosquitoes were 16.9 and 11% at 6, 13 and 20 days postfeeding, respectively, and 1/2 and 2/2 infected mosquitoes transmitted virus on da ...19911646286
differences in fusogenicity and mouse neurovirulence of japanese encephalitis viruses.the fusogenic capacity in ap-61 cell monolayers of 10 strains of japanese encephalitis (je) virus from different geographic locations was compared. one strain, isolated from beijing (je-bei), did not fuse ap-61 cells after replication (fusion from within; ffwi), whereas all other strains fused these cells by 72 h post-infection. je-bei also readily established a non-cytolytic persistent infection in ap-61 cells. differences in the envelope proteins of fusogenic and non-fusogenic virus were detec ...19911650549
[the ockelbo disease, nephropathia epidemica and tularemia. a great deal is known about the infectious diseases in the north--but quite a few question-marks are left]. 19911650870
putative papain-related thiol proteases of positive-strand rna viruses. identification of rubi- and aphthovirus proteases and delineation of a novel conserved domain associated with proteases of rubi-, alpha- and coronaviruses.a computer-assisted comparative analysis of the amino acid sequences of (putative) thiol proteases encoded by the genomes of several diverse groups of positive-stranded rna viruses and distantly related to the family of cellular papain-like proteases is presented. a high level of similarity was detected between the leader protease of foot-and-mouth-disease virus and the protease of murine hepatitis coronavirus which cleaves the n-terminal p28 protein from the polyprotein. statistically significa ...19911652473
isolation of getah virus from dead fetuses extracted from a naturally infected sow in japan.three viruses producing a cytopathic effect in cell culture were isolated from dead fetuses extracted from a naturally infected sow, and were found to be serologically identical by neutralization tests. one of the viruses was cloned and named the sakura strain. the sakura strain was identified as getah virus by cross-neutralization tests.19911652864
a possible role of the viral core protein in the regulation of assembly and disassembly of alphavirus many viral systems the genome is part of a stable nucleoprotein complex which has to be dissociated early in infection, in order to make the genome accessible for transcription or translation. it is not directly evident how a nucleoprotein generated as a stable complex during virus assembly can be dissociated during the initial steps of viral multiplication. during analyses of the molecular biology of alphavirus replication it has been shown that the core protein of these viruses is a multifu ...19911656932
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
the use of antiidiotype antibodies for the characterization of protein-protein interactions. 19911658573
antibody-mediated clearance of alphavirus infection from neurons.humoral immunity is important for protection against viral infection and neutralization of extracellular virus, but clearance of virus from infected tissues is thought to be mediated solely by cellular immunity. however, in a scid mouse model of persistent alphavirus encephalomyelitis, adoptive transfer of hyperimmune serum resulted in clearance of infectious virus and viral rna from the nervous system, whereas adoptive transfer of sensitized t lymphocytes had no effect on viral replication. thr ...19911658936
effect of viral inoculum size on appearance of clinical signs in equine getah virus infection.a study was performed to examine the effect of viral inoculum size on the appearance of clinical signs in equine getah virus (gv) infection by intramuscular inoculation with 10(1.3) to 10(6.3) tcid50 of the mi-110 strain in 6 experimental horses. when inoculated with more than 10(3.3) tcid50 of the virus, every horse developed pyrexia, edema in the hind legs, serous nasal discharge, lymphopenia and viremia in the relatively early stage of disease. on the other hand, enlargement of the submandibu ...19911661174
intranasal infection of getah virus in experimental horses.aerosol transmission in equine getah virus (gv) infection was examined by intranasal inoculation with 10(3.0) to 10(7.0) tcid50 of the mi-110 strain in 7 experimental horses. the establishment of intranasal infection of gv was confirmed in all these horses by detecting serum neutralizing antibody against the mi-110 strain. horses inoculated with more than 10(4.0) tcid50 of the virus manifested mild pyrexia, eruptions, serous nasal discharge, lymphopenia or monocytosis. viremia ranging from 10(1. ...19911661175
susceptibility of pregnant hamster, guinea pig, and rabbit to the transplacental infection of getah virus. 19911665083
effect of hypertonic medium on the protein synthesis in l-a9 and aedes albopictus cells infected with mayaro virus. 19911668789
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
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
barmah forest virus. 19911678035
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
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
comparative therapeutic efficacy of recombinant interferons-alpha, -beta, and -gamma against alphatogavirus, bunyavirus, flavivirus, and herpesvirus infections.recombinant (r) preparations of interferons (ifn)-alpha, -beta, and -gamma were shown to protect mice against experimental virus infections with herpes simplex virus type 2 (hsv-2), and with three rna-containing viruses from different families: banzi, a flavivirus; semliki forest virus (sfv), an alphatogavirus; and caraparu, a bunyavirus. the antiviral effects of the three different types of ifn were different with each virus. hsv-2 was the most sensitive virus, followed by sfv. against banzi vi ...19901696607
serologically defined linear epitopes in the e2 envelope glycoprotein of semliki forest virus.a set of 41 overlapping peptides, representing the complete sequence of sfv-e2 protein were synthesized and analyzed in the elisa test against murine anti-sfv sera. no single peptide was recognized by all antisera. eight peptides were found to be highly reactive with hyperimmune anti-sfv sera. six out of the eight peptide sequences coincide with the most hydrophilic regions of sfv-e2. out of these, four peptides (amino acid positions 16-35, 61-80, 166-185, 286-305) that contain the least number ...19901696808
effect of heat shock on gene expression of aedes albopictus cells infected with mayaro virus.three major mayaro virus proteins of 62, 50 and 34 kda were detected in aedes albopictus cells after 48 h postinfection at 28 degrees c. when the infected cells were shifted from 28 to 37 degrees c for 90 min (heat shock conditions), the synthesis of two major heat shock proteins (hsp) 82 and 70 kda was induced concomitantly with strong inhibition of virus and normal protein synthesis. total cellular rna was isolated from mock and infected cells incubated at 28 degrees c or under heat shock. nor ...19911711236
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
[a monoclonal antibody study of the receptor area of the venezuelan encephalitis virus].the receptor region for virus-cell interaction in venezuelan equine encephalomyelitis (vee) and eastern equine encephalomyelitis (eee) viruses was studied using a panel of 17 monoclonal antibodies (mca). they were able to block agglutination of goose erythrocytes. the dominant role of glycoprotein e2 in the formation of viral receptor for eee and vee viruses was demonstrated. competitive radioimmunoassay identified three antigenic sites in this region. these sites were also responsible for virus ...19911723820
replication complexes associated with the morphogenesis of rubella virus.thin section electron microscopy was used to investigate cellular changes associated with the replication of rubella virus (rv) in vero cells and to compare these changes to those of the related alphavirus, semliki forest virus (sfv). conspicuous membrane-bound cytoplasmic vacuoles analogous to the alphavirus replication complexes were observed in rv infected cells but not in mock infected cells. the vacuoles were characterised by membrane-bound vesicles measuring about 60 nm which often display ...19921729987
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
[preliminary study on the presence of arbovirus in the populations of corrientes and misiones].human seroprevalence of flavivirus was determined by hemagglutination inhibition tests on 479 sera from misiones and 49 from corrientes provinces. paraná and uruguay river bank communities from argentina and neighbouring countries carry out frequent traffic across the rivers. with the aim of searching for a possible introduction of dengue virus from brasil or/and paraguay, reactivity among people from paraná and uruguay river communities was compared with those from mountain communities. two ser ...19911815271
detection of alphaviruses in a genus-specific antigen capture enzyme immunoassay using monoclonal antibodies.a genus-specific antigen capture assay using similar combinations of monoclonal antibodies for capture and detection of 24 alphaviruses belonging to the seven serocomplexes was developed. the sensitivity of the test ranged from 10(3.4) 50% tissue culture infective doses/ml for o'nyong-nyong virus to 10(6.1) 50% tissue culture infective doses/ml for middelburg virus. the antigen capture test uses a combination of cross-reacting monoclonal antibodies directed against the nucleocapsid protein and e ...19911847149
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
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
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
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
use of biotechnical methods in veterinary medicine.biotechnological methods offer promising approaches for improved diagnostic and prophylactic purposes. the following biotechnological techniques are used in the institute of virology at the hanover veterinary school:--production of monoclonal antibodies directed against viral and bacteria-specific antigens such as bovine virus diarrhoea virus, classical swine fever (hog cholera) virus, feline leukaemia virus, animal parvoviruses, alphavirus, brucella and francisella--establishment of improved an ...19901966725
the "merry-go-round": alphaviruses between vertebrate and invertebrate cells. 19901977293
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