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Acta virologica

Volume 46 / 2002 / number 4

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• Q FEVER – STILL A QUERY AND UNDERESTIMATED INFECTIOUS DISEASE
• CHIMERIC NEWCASTLE DISEASE VIRUS NUCLEOCAPSID WITH PARTS OF VIRAL HEMAGGLUTININ-NEURAMINIDASE AND FUSION PROTEINS
• ANALYSIS OF REGULATION OF POLYOMAVIRUS PROMOTERS BY A LUCIFERASE REPORTER SYSTEM
• NATURAL INFLUENZA A VIRUS INFECTION OF MICE ELICITS STRONG ANTIBODY RESPONSE TO HA2 GLYCOPOLYPEPTIDE
• A NEW CELL LINE FROM THE EMBRYONIC TISSUES OF CULEX TRITAENIORHYNCHUS AND ITS SUSCEPTIBILITY TO CERTAIN FLAVIVIRUSES
• NUCLEOTIDE SEQUENCE OF A THAI ISOLATE OF PAPAYA RINGSPOT VIRUS TYPE W
• SEQUENCE AND PHYLOGENETIC ANALYSIS OF THE FUSION PROTEIN CLEAVAGE SITE OF NEWCASTLE DISEASE VIRUS FIELD ISOLATES FROM IRAN
• MIXED INFECTION OF BLACK CURRANT (RIBES NIGRUM L.) PLANTS WITH BLACKCURRANT REVERSION ASSOCIATED VIRUS AND RHABDOVIRUS-LIKE PARTICLES WITH SYMPTOMS OF BLACK CURRANT REVERSION DISEASE
• STUDY OF THE EFFECT OF THE MIDGUT BACTERIAL FLORA OF CULEX QUINQUEFASCIATUS ON THE SUSCEPTIBILITY OF MOSQUITOES TO JAPANESE ENCEPHALITIS VIRUS
• ANNOUNCEMENT
• CONTENTS
• SUBJECT INDEX
• INDEX TO AUTHORS

Summary. – Coxiella burnetii (C.b.) is a strictly intracellular, Gram-negative bacterium. It causes Q fever in humans and animals worldwide. The animal Q fever is sometimes designated ”coxiellosis”. This infection has many different reservoirs including arthropods, birds and mammals. Domestic animals and pets, are the most frequent source of human infections. Q fever may appear basically in two forms, acute and chronic (persistent). The latter form of Q fever in animals is characteristic by shedding C.b. into the environment during parturition or abortion. Human Q fever results usually from inhalation of contaminated aerosols originating mostly from tissue and body fluids of infected animals. Q fever may appear in humans either in an acute form accompanied mainly by fever (pneumonia, flu-like disease, hepatitis) or in a chronic form (mainly endocarditis). Diagnosis of Q fever is based on isolation of the agent in cell culture, its direct detection, namely by PCR, and serology. Detection of high phase II antibodies titers 1–3 weeks after the onset of symptoms and identification of IgM antibodies are indicative to acute infection. High phase I IgG antibody titers >800 as revealed by microimmunofluorescence offer evidence of chronic C.b. infection. For acute Q fever, a two-weeks-treatment with doxycycline is recommended as the first-line therapy. In the case of Q fever endocarditis a long-term combined antibiotic therapy is necessary to prevent relapses. Application of Q fever vaccines containing or prepared from phase I C.b. corpuscles should be considered at least for professionally exposed groups of the population. Infections caused by C.b. are spread worldwide and may pose serious and often underestimated health problems in human but also in veterinary medicine. Though during the last decades substantial progress in investigation of C.b. has been achieved and many data concerning this pathogen has been accumulated, some questions, namely those related to the pathogenesis of the disease, remain open.

Key words: Q fever; epidemiology; clinical presentation; pathogenesis; immunity; diagnosis; treatment; prevention
Acta virologica 46: 193 – 210, 2002

Summary. – The nucleocapsid (NP) protein of Newcastle disease virus (NDV) self-assembled in Escherichia coli as ring-like and herringbone-like particles. Several chimeric NP proteins were constructed in which the antigenic regions of the hemagglutinin-neuraminidase (HN) and fusion (F) proteins of NDV, myc epitope, and six histidines (a hexa-His tag) were linked to the C-terminus of the NP monomer. These chimeric proteins were expressed efficiently in soluble form in E. coli as detected by Western blot analysis. Electron microscopy of the purified products revealed that they self-assembled into ring-like particles. These chimeric particles exhibited antigenicity of the myc epitope, suggesting that the foreign sequences were exposed on the surface of the particles. Chickens inoculated with the chimeric particles mounted an immune response against NDV, suggesting the possibility of use of the ring-like particle as a carrier of immunogens in subunit vaccines and immunological reagents.

Key words: NDV; nucleocapsid; chimeric NP protein; protein assembly; molecular carrier
Acta virologica 46: 211 –217, 2002

Summary. – The transcription factor Ying-Yang 1 (YY1), which has been shown to activate basal transcription from mouse polyomavirus (Py) late promoter, does not interact with the main viral regulatory protein, the large tumor antigen (LT) in vivo directly but via DNA (Španielová and Velková, 2001). In this report, the role of association of YY1 with LT in regulation of the Py late promoter was studied by a luciferase reporter system. The distance between YY1 and LT binding sites in the viral regulatory region was extended by insertion of a transcriptionally inert sequence 166 nucleotides (nt) long thus making physical contact between LT and YY1 bound to their sites impossible or difficult. Analysis of viral early and late promoter activities was performed in the presence or absence of viral early tumor antigens and in the presence or absence of an inhibitor of DNA replication. The study indicated that regulation of the Py late promoter is DNA replication-linked and that association of both proteins may be involved in this type of regulation. Moreover, the plasmid DNA replication assay showed that insertion of the inert sequence between the ori-core and enhancer restricted replication of the reporter plasmid.

Key words: polyomavirus; late promoter; YY1 protein, large T antigen
Acta virologica 46: 219 – 227, 2002

Summary. – Two influenza viruses, A/Dunedin/4/73 (H3N2) and A/Mississippi/1/85 (H3N2) were adapted to BALB/c mice. Groups of BALB/c mice were intranasally (i.n.) infected with either single dose of particular virus strain or successively with both virus strains and titers of serum antibodies against influenza virus antigens (”influenza virus antibodies”) and those just against the HA2 part of hemagglutinin (HA) (”HA2 antibodies”) were determined. Successive infection with virus strains Dunedin and Mississippi in interval of 21 days led to the strong increase of the proportion of anti-HA2 antibodies in sera, though whole antiviral titres remained in general unchanged. These observations confirmed that the HA2 glycopolypeptide (gp) part of influenza virus HA is very strong immunogen in natural infection.

Key words: antibody response; HA2 glycopolypeptide; influenza vaccine; mouse-adapted influenza virus; natural influenza infection
Acta virologica 46: 229 – 236, 2002

Summary. – A new cell line from the embryonic tissue of Culex tritaeniorhynchus mosquito was established. Morphological studies carried out at the 45th passage level (P-45) showed four different cell types viz. epithelial-like cells, fibroblast-like cells, giant cells and vacuolated cells. Karyological studies indicated diploid (2n = 6) chromosomes in majority of cells irrespective of passage level. A twelve-fold increase of cell number was observed in 10 days at P-49. The cells could be preserved in liquid nitrogen for more than 40 months. Isoenzyme profile analysis with four enzymes clearly indicated that this cell line was derived from C. tritaeniorhynchus. This cell line was susceptible to Japanese encephalitis (JEV) and West Nile viruses (WNV) but not to Dengue 1-4 (DEN 1-4) viruses. Protein of 38 K was detected in the membrane fraction of the cells from this and the C6/36 cell line, which was found to bind DEN 1-4 viruses. These data suggest that DEN viruses bind to this membrane protein and probably enter into the cells but do not continue further in the replication process.

Key words: cell membrane protein; Culex tritaeniorhynchus; Dengue viruses; isoenzyme; Japanese encephalitis virus; mosquito cell line; virus susceptibility; West Nile virus
Acta virologica 46: 237 – 240, 2002

Summary. – The complete nucleotide sequence of a Thai isolate of Papaya ringspot virus (PRSV) type W (PRSV-W) was determined. The viral genome is 10,323 nucleotides (nts) long and contains an ORF encoding polyprotein 3,343 amino acids (aa) long, flanked with 5'- and 3'-non-coding regions (NCRs) of 85 and 206 nts, respectively. Out of the ten putative proteins P1 is the most variable (73.9% similarity) as compared to the PRSV type P (PRSV-P) sequences, while the CI protein is most conserved (99.1% similarity). The sequence similarity among the type W and P isolates also suggests that the P type arose from the W type. However, no significant difference between types P and W that would account for the host specificity was disclosed.

Key words: papaya ringspot virus; genome; nucleotide sequence
Acta virologica 46: 241 – 246, 2002

Summary. – Nine Newcastle disease virus (NDV) isolates from Newcastle disease (ND) outbreaks in different regions of Iran were characterized at molecular level. Sequence analysis revealed that the isolates shared two pairs of arginine and a phenylalanine at the N-terminus of the fusion (F) protein cleavage site similarly to other velogenic isolates of NDV characterized earlier. Eight of the nine isolates had the same amino acid sequence as VOL95, a Russian NDV isolate from 1995. However, one isolate, MK13 showed 5 amino acid substitutions, of which 3 have been reported for other velogenic NDV isolates. These results suggest that the origin of the outbreaks of ND in different parts of Iran in 1995–1998 is VOL95.

Key words: Newcastle disease virus; fusion protein gene; cleavage site; nucleotide sequence; phylogenetic analysis
Acta virologica 46: 247 – 251, 2002

Summary. – Black currant plants of cvs. Black Smith and Karlštejnský dlouhohrozen showing symptoms of severe Russian (R) form of black currant reversion disease (BCRD) were found in 1999–2000 in the Czech Republic. Five selected plants of both cultivars originating from two distant loci were tested by polymerase chain reaction (PCR) for presence of the Blackcurrant reversion associated virus (BRAV), the causal agent of BCRD. In all plants, virus-specific 215 nt cDNA fragments proving the presence of BRAV were obtained. Moreover, in two of those five black currant plants, rhabdovirus-like particles were found in ultrathin sections by electron microscopical examinations. The particles measured 200–347 nm by 64–90 nm. They occurred mostly within nuclei of parenchyma cells of vascular bundles as single particles, rafts of particles, but also in aggregates. They were found also in the perinuclear space and occasionally directly in the cytoplasm. Clusters of particles either within the nucleus or in the perinuclear space were membrane-bound. We bring evidence on the occurrence of the severe (R) form of BCRD and the first evidence of BRAV in the Czech Republic.

Key words: black currant reversion disease; electron microscopy; PCR; rhabdovirus-like particles; Ribes spp.; Blackcurrant reversion associated virus
Acta virologica 46: 253 – 256, 2002

Summary. – Culex quinquefasciatus mosquitoes were collected from the field and microbial flora was isolated from their midgut. Isolates belonging to 13 different genera were obtained. Four most abundant isolates viz. Pseudomonas sp., Acinetobacter junii, Staphylococcus epidermis and Aeromonas culicicola were used to study their effect on the susceptibility of mosquitoes to Japanese encephalitis virus (JEV). Incorporation of individual isolates in the mosquito bloodmeal resulted in an increased susceptibility of mosquitoes to the virus. However, only the effects of Pseudomonas sp. and Acinetobacter junii could be statistically evaluated but they were found insignificant.

Key words: Culex quinquefasciatus; Japanese encephalitis virus; midgut; bacterial flora; susceptibility
Acta virologica 46: 257 – 260, 2002

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