• Journal of Microbiology and Biotechnology
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• v.29 no.11
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• pp.1790-1798
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• 2019

Flock House virus (FHV), an insect RNA virus, has a bipartite genome. FHV RNA1 can be packaged in turnip yellow mosaic virus (TYMV) as long as the FHV RNA has a TYMV sequence at the 3'-end. The encapsidated FHV RNA1 has four additional nucleotides at the 5'-end. We investigated whether the recombinant FHV RNA1 could replicate in mammalian cells. To address this issue, we prepared in vitro transcribed FHV RNAs that mimicked the recombinant FHV RNA1, and introduced them into baby hamster kidney (BHK) cells. The result showed that the recombinant FHV RNA1 was capable of replication. An eGFP gene inserted into the frame with B2 gene of the FHV RNA1 was also successfully expressed. We also observed that eGFP expression at the protein level was strong at 28℃ but weak at 30℃. Sequence analysis showed that the 3'-ends of the RNA1 and RNA3 replication products were identical to those of the authentic FHV RNAs. This indicates that FHV replicase correctly recognized an internally-located replication signal. In contrast, the 5'-ends of recombinant FHV RNA1 frequently had deletions, indicating random initiation of (+)-strand synthesis.

• BMB Reports
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• v.47 no.6
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• pp.330-335
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• 2014

Turnip yellow mosaic virus (TYMV) is a spherical plant virus that has a single 6.3 kb positive strand RNA as a genome. In this study, RNA1 sequence of Flock house virus (FHV) was inserted into the TYMV genome to test whether TYMV can accommodate and express another viral entity. In the resulting construct, designated TY-FHV, the FHV RNA1 sequence was expressed as a TYMV subgenomic RNA. Northern analysis of the Nicotiana benthamiana leaves agroinfiltrated with the TY-FHV showed that both genomic and subgenomic FHV RNAs were abundantly produced. This indicates that the FHV RNA1 sequence was correctly expressed and translated to produce a functional FHV replicase. Although these FHV RNAs were not encapsidated, the FHV RNA having a TYMV CP sequence at the 3'-end was efficiently encapsidated. When an eGFP gene was inserted into the B2 ORF of the FHV sequence, a fusion protein of B2-eGFP was produced as expected.

• Korean Journal of Veterinary Research
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• v.45 no.3
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• pp.311-323
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• 2005

This study tested the effect of a trivalent (feline panleukopenia; FPV, feline viral rhinotracheitis; FHV, feline calicivirus infection; FCV) inactivated vaccine in cats. The vaccine was tested for the safety in guinea pigs, mice and cats. Also, it was tested for the efficacy in cats. The vaccine was inoculated to cats at 7~9 and 10~12 weeks of age (conventional schedule) and the serological response to vaccination was assessed and was compared to the unvaccinated group. All cats were bled by jugular venipuncture for FPV, FHV and FCV specific serological test (virus neutralizing antibody, VN) at 7~9, 10~12 and 13~15 weeks. After last bleeding, all cats were inoculated with each virus (FPV : orally $2ml\;10^{7.5}\;TCID_{50}/ml$, FHV : nasally $1ml\;10^{7.0}\;TCID_{50}/ml$ and FCV : nasally $1ml\;10^{7.0}\;TCID_{50}/ml$). The Vaccine verified excellent protective effect in guinea pigs, mice and cats. The VN antibody titers of the unvaccinated group cats against FPV, FHV and FCV were <2~16, on the other hand the vaccinated group cats were $512{\sim}{\geq}4096$, 64~1024 and 64~1024, respectively. When all cats were challenged with virulent viruses, the survival rates of the vaccinated group cats were over 80%, while the survival rates of the unvaccinated group cats were less 20%. The typical clinical signs were not observed in the vaccinated group cats, but the typical clinical signs and histopathological lesions were observed in the unvaccinated group cats. As the result of tests, the VN values obtained in this study appeared to be high enough to protect cats from viral challenges. The trivalent (FPV, FHV, and FCV) inactivated vaccine seemed to be very effective, for prevention of feline viral diseases (FPV, FHV, and FCV).

• Korean Journal of Veterinary Research
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• v.63 no.1
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• pp.5.1-5.9
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• 2023

Feline panleukopenia virus (FPV), feline calicivirus (FCV), and feline herpesvirus type-1 (FHV-1) are major infectious pathogens in cats. We evaluated the immunogenicity of a new vaccine containing inactivated FPV, two FCVs, and FHV-1 in animals. An FPV, two FCVs, and an FHV-1 isolate were continuously passaged 70, 50, 80, and 100 times in CRFK cells. FP70, FC50, FC80, and FH100 were propagated and used as vaccine antigens. Two inactivated feline virus vaccines, feline rehydragel-adjuvanted vaccine (FRAV) and feline cabopol-adjuvanted vaccine (FCAV) were prepared and inoculated into mice and guinea pigs. Humoral immune responses were measured using hemagglutination inhibition (HI) for FPV and virus-neutralizing antibody (VNA) for two FCVs and FHV-1 tests. Serial passages in CRFK cells resulted in increase in titers of FPV and two FCVs but not FHV-1 The FCAV induced higher mean HI and VNA titers than the FRAV in guinea pigs; therefore, the FCAV was selected. Cats inoculated with FCAV developed a mean HI titer of 259.9 against FPV, and VNA titers of 64, 256, and 3.2 against FCV17D03, FCV17D283, and FHV191071, respectively. Therefore, cats inoculated with the FCAV showed a considerable immune response after receiving a booster vaccination.

• Korean Journal of Veterinary Research
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• v.62 no.3
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• pp.24.1-24.7
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• 2022

Incidences of major feline viral diseases provide basic information for preventing viral disease in cats. Despite the growing interest in feline viral diseases, sero-surveillances have been lacking. In this study, we analyzed the diagnoses of feline viral diseases and conducted a sero surveillance of feline panleukopenia virus (FPV), feline calicivirus (FCV), feline herpesvirus-1 (FHV-1), and feline infectious peritonitis virus (FIPV) in Korean cats. Of the 204 confirmed cases since 2015, the numbers of diagnoses for FPV, FIPV, FCV, feline influenza virus, and FHV-1 were 156, 32, 12, 3, and 1 case, respectively. In total, 200 sera, collected between 2019 and 2021, were screened for the presence of antibodies against FPV, 2 FCVs, FHV-1, and FIPV using a hemagglutination inhibition test and a virus-neutralizing assay (VNA). The overall seropositive rates in cats tested for FPV, the 2 FCVs, FHV-1, and FIPV were 92.5%. 42.0%, 37.0%, 52.0%, and 14.0%, respectively. A low correlation (r = 0.466) was detected between the VNA titers of 2 FCV strains. The highest incidence and seropositive rate of FPV reveal that FPV is circulating in Korean cats. The low r-value between 2 FCVs suggests that a new feline vaccine containing the 2 kinds of FCVs is required.

• Korean Journal of Veterinary Service
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• v.46 no.4
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• pp.269-281
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• 2023

In this study, a new triplex real-time quantitative reverse transcription polymerase chain reaction (tqRT-PCR) assay was developed for the rapid and differential detection of three feline viral pathogens including feline calicivirus (FCV), feline herpesvirus 1 (FHV-1), and influenza A virus (IAV) in a single reaction. The assay specifically amplified three targeted viral genes with a detection limit of below 10 copies/reaction. The assay showed high repeatability and reproducibility, with intra- and inter-assay coefficients of variation of less than 1%. Based on the diagnostic results of the assay using 120 clinical samples obtained from cats with feline respiratory disease complex (FRDC)-suspected signs, the prevalence of FCV, FHV-1, or IAV was 43.3%, 22.5%, or 0%, respectively, indicating that the diagnostic sensitivity was comparable or superior to those of previously reported monoplex qRT-PCR/qPCR assays. The dual infection rate for FCV and FHV-1 was 8.3%. These results indicate that FCV and FHV-1 are widespread and that co-infection with FCV and FHV-1 frequently occur in the Korean cat population. The developed tqRT-PCR assay will serve as a promising tool for etiological and epidemiological studies of these three bacterial pathogens, and the prevalence data for three feline viruses obtained in this study will contribute to expanding knowledge about the epidemiology of FRDC in the current Korean cat population.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.117.3-118
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• 2003

We tested for the presence of double-stranded RNA (dsRNA) mycovirus in 827 Fusarium graminearum isolated from diseased barley and maize. dsRNA mycoviruses with various sizes were isolated. Of them, it was previously reported that dsRNA from DK2l isolate had pronounced morphological changes, including reduction in mycelial growth, increased to red pigmentation, reduced virulence and sporulation. (Chu et al., Appl. Environ. Microbiol. 2002). For better understanding of this hypovirulence associated with DK2l dsRNA virus, we determined the complete nucleotide sequence of dsRNA genome and named Fusarium hypovirus DK2l strain (Fhv-DK2l ). Genomic RNA of Fhv-DK2l was determined to be 6625 nucleotides in length excluding the poly (A) tail and contained three putative open reading frame. RNA-dependent RNA polymerase (RdRp) and helicase domain were expected in ORF A, 54 to 4709 nucleotide position. ORE B, 4752 to 5216 nucleotide position, and ORF C, 5475 to 6578 nucleotide position, were predicted to encode 16.7kDa and 41.3kDa protein respectively each. We could not detect any conserved domains from these two proteins. Phylogenetic analysis showed Fhv-DK2l was related to Cryphonectria hypovirus 3. Ten additional isolates were found that were infected with dsRNA mycoviruses. These mycoviruses contain 2 to 4 different segments of dsRNAs with the size range of approximately 1.7 to 10-kbp in length. The presence of dsRNAs isolates did not affect colony morphology and were transmissible through conidia and ascospore with incidence of 30-100％. These results indicate that there is genomic diversity of dsRNA mycoviruses that infect F. graminearum isolates and that impact of virus infection on host's morphology and virulence is determined by the interaction between dsRNAs and the fungal host, not by the mere presence of the dsRNAs

• Tribology and Lubricants
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• v.9 no.2
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• pp.16-21
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• 1993

Alkylbenzenes used as the synthetic lubricant base stocks were composed of the mixture of the various kinds of aromatic hydrocarbons. Their compositions have affected on the quality of synthetic alkylbenzene lubricants. Therefore, the rapid and accurate methods for the composit ional analysis are important. In this study, the compositions of the alkylbenzenes (Hv. LAB, FHv. LAB, Hv, BAB, DAB[HF], DAB[$AlCl_3$]) as synthetic base stocks have been investigated according to six average structural parameters(Tar, Nal, Asub, $\bar{n}$, nb, $T\alpha$) in the view of the molecular structures by $^{13}C-NMR$ spectroscopy. The experimental results of the oxidation $\varepsilon$ thermal stability tests have been related to the results of the molecular structural analysis.

• Journal of Veterinary Clinics
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• v.30 no.3
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• pp.210-213
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• 2013

We herein describe a feline case of facial dermatitis whose histopathological features resembled to those of FHV-associated ulcerative dermatitis. A 3-year-old, intact male domestic short-haired cat was presented with 2-years history of pruritic dermatitis that initially appeared on periocular area and extended toward the entire face. The cat had ocular discharge and conjunctivitis from 2-month of age. Clinically, skin lesions were characterized as erythema, erosions and ulcers covered with crusts on the facial and perianal area. Histopathologically, the facial lesion was characterized as interface dermatitis with hydropic degeneration at the basal layer, and single cell necrosis of keratinocytes. In addition, the epidermal and dermal necrosis infiltrated with eosinophils, and intranuclear inclusion bodies in keratinocytes were also recognized. Moreover, feline herpesvirus-1 gene was detected by a PCR analysis using a swab obtained from the crusted lesions. Based upon these findings, the present case was considered as having FHV-associated ulcerative dermatitis. Therapy including oral acyclovir and topical recombinant feline interferon omega resulted in marked improvement of the skin and mucosal lesions.

• Korean Journal of Veterinary Service
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• v.45 no.3
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• pp.145-153
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• 2022

Pathogens such as feline herpesvirus, feline calicivirus, Bordetella bronchiseptica, Chlamydia felis, Mycoplasma felis and Pasteurella multocida usually cause feline upper respiratory tract disease (URTD). Real-time PCR was used to analyze the detection and prevalence of the most common respiratory pathogens in cats with (n=69) and without respiratory signs (n=31). Pathogens were detected in 53 cats, divided into 37 (69.8%) with a single pathogen, 15 (28.3%) with two pathogens, and 1 (1.9%) with three pathogens. M. felis had the highest detection rate in 29 (42.0%) cats, P. multocida was detected in 18 (26.1%), FHV in 10 (14.5%), FCV in 7 (10.1%), B. bronchiseptica in 3 (4.3%), and C. felis in 2 (2.9%). M. felis was the most frequently detected pathogen in cats living outdoors without vaccination. Of the 37 cats infected with single pathogen, nasal discharge was observed in 13 (35.1%), ocular signs in 6 (16.2%), drooling in 5 (13.5%), dyspnea in 3 (8.1%), and asymptomatic in 10 (27.0%). In 51 outdoor and 49 indoor cats, pathogens were detected in 35 (68.6%) and 18 (36.7%) cats, respectively. Of the 29 cats infected with M. felis, 22 (75.9%) showed respiratory signs, and 7 (24.1%) were healthy. In the age of the 53 positive cats, 10 (18.9%) were under the age of 1 year, 26 (49.1%) were aged 1~3 years, and 17 (32.1%) were aged 3 years or older. Although the number of cats in the study was small, the results can provide valuable data on the prevalence of URTD in Korean cats.