• The Journal of Korean Society of Virology
• /
• v.27 no.1
• /
• pp.1-8
• /
• 1997

Human caliciviruses (HuCVs) cause sporadic cases and outbreaks of acute gastroenteritis (AGE). Three major genogroups of HuCVs have been described including the Norwalk virus (NV)-, the Snow Mountain virus (SMA)-, and the Sapporo-genogroups. This study describes the detection and genetic variation of HuCVs from hospitalized infants with AGE in Korea by RT-PCR and sequencing. The cDNA fragments of 206 to 470bp corresponding to the region of 3 primer pairs (36/35, 35/51 or 3/51) in the polymerase region of NV were generated. Of 185 stools screened, 8% were positive by RT-PCR and their sequences showed that all strains contained the GLPSG and YGDD motifs which are conserved for HuCVs. Amino acid (aa) sequence analysis showed that these strains can be divided into 3 major genogroups. High conservation was observed in that one strain shares 100% of aa sequence with Southampton virus, another shares 99% with the Sapporo virus, and six strains share 90 to 95% with Snow Mountain virus. However, significant sequence variation was also found in other strains. This study indicates that all major genogroups of HuCVs are circulating in Korea.

• The Journal of Korean Society of Virology
• /
• v.27 no.2
• /
• pp.185-195
• /
• 1997

Sequence comparison of the RNA-dependent RNA polymerase of human caliciviruses (HuCVs) from Korean children with gastroenteritis revealed significant genetic variation among them. cDNA clones were produced from the HuCVs collected from pediatric population during a period of 1987-1994. The application of reverse transcription-polymerase chain reaction (RT-PCR) using primers directed to the RNA-dependent RNA polymerase region within ORF1 of Norwalk virus (NV) showed that 13.7% of HuCVs yielded PCR products of similar size to the NV prototype, NV8FIIa/68/US, with exceptions of HuCV 185/87/Korea and HuCV 1115/90/Korea. Computer analyses showed that the PCR products had a continuous protein encoding frame on the positive strand, and contained GLPSG and YGDD amino acid motifs at the predicted distance from primers. Alignment of the amino acid sequences of HuCVs with previously published sequences for Snow Mountain agent (SMA), NV, and Sapporo/82/Japan indicated that these strains can be divided into four major genogroups. There were 10 (45%) SMA-like CVs, one (4.5%) NV-like HuCVs, two (9%) Sapporo-like HuCVs, and nine (41%) unidentified HuCVs. This fourth genogroup should be investigated further. HuCV 185/87/Korea and HuCV 1115/90/Korea, Sapporo-like CVs, were genetically distinct from previously characterized HuCVs and more closely related to known animal CVs. One of the animal CV-like strain, HuCV 185/87/Korea, showed nucleotide and amino acid homology of only 67% and 73% with the prototype Sapporo/82/Japan. Further characterization of animal and human CV genomes and studies of possible cross-transmission of CVs from animals to humans are likely to be beneficial in understanding the epidemiology of HuCVs.

• Proceedings of the Zoological Society Korea Conference
• /
• 1996.10a
• /
• pp.239.1-239
• /
• 1996

No Abstract, See Full Text

• The Journal of Korean Society of Virology
• /
• v.27 no.2
• /
• pp.151-160
• /
• 1997

In view of the potential of replicase protein as a diagnostic reagent for human caliciviruses (HuCVs), we have cloned and over-expressed this gene from the Snow Mountain-like Korean strains in Escherichia coli as a fusion protein with glutathione S-transferase (GST), and described the preliminary antigenic characterization of the recombinant products. Each 470bp fragment corresponding to highly conserved region of RNA-dependent RNA polymerase was generated by RT-PCR from stools of two diarrheal children, cloned in pMOSBlue T-vector, and subcloned between the EcoRI and SalI restriction sites of pGEX-4T-3, a GST gene fusion vector, yielding $pGCV_{pol}$. This construct expressed a Snow Mountain-like HuCV replicase under the control of the IPTG-inducible tac promoter. An extract prepared by sonication of the E. coli cell inclusion bodies bearing $pGCV_{pol}$ products was purified and analyzed by SDS-PAGE. After Coomassie blue staining, it was shown that the recombinant replicase migrated on the gels with an approximate molecular mass of 46.5 kDa, that was subsequently cleaved into a 26 kDa GST fragment and a 20.5 kDa replicase protein upon digestion with thrombin protease. The replicase was recognized on immunoblotting with the sera from symptomatic children with the HuCV-associated diarrhea but not by asymptomatic sera from adults. The results presented the first biological activity of individually expressed HuCV replicase subunit and provided important reagents for diagnosis of HuCV infection.

• Journal of Veterinary Science
• /
• v.22 no.3
• /
• pp.32.1-32.8
• /
• 2021

Feline calicivirus (FCV) is a highly infectious pathogen in cats and widely distributed worldwide with high genetic variation. Full-length open reading frame 2 of 5 from recently isolated Korean FCV isolates were sequenced and compared with those of global isolates. The results of phylogenetic analysis supported dividing global FCV isolates into two genogroups (type I and II) and demonstrated the presence of genogroup II in Korea, indicating their geographic spread in East Asia. High sequence variations in region E of the FCV isolates emphasizes that a novel vaccine needs to be developed to induce protective immunity against various FCV strains.

• Korean Journal of Veterinary Research
• /
• v.60 no.4
• /
• pp.195-202
• /
• 2020

Feline calicivirus (FCV) infection results in a common upper respiratory disease associated with oral ulceration in cats. Although FCV infection has been reported in cats worldwide, the biologic and genetic features of South Korean FCV are unclear. We aimed to investigate the biological and genetic features of South Korean FCV isolates. Crandell-Rees feline kidney (CRFK) cells were used to isolate FCV from 58 organ homogenate samples. The FCV isolates were confirmed by cytopathic effects, immunofluorescence, electron microscopy, and reverse transcription polymerase chain reaction assays. Viral genetic analysis was carried out with VP2 gene and complete genomes of FCVs. Five viruses propagated in CRFK cells were confirmed to be FCVs. The FCV17D283 isolate showed the highest viral titer of 107.2 TCID50/mL at 36 h post-inoculation. Korean FCV isolates did not grow well in Vero, BHK-21, A72, or Madin-Darby canine kidney cells. The FCV17D03 and FCV17D283 isolates had the highest genetic similarity (80.1% and 86.9%) with the UTCVM-H1 and 14Q315 strains, which were isolated in the United States and South Korea in 1995 and 2014, respectively. We isolated five FCVs from cats and detected important genetic differences among them. FCV isolates did not show any virulent effects in mice.