• Korean Journal of Microbiology
• /
• v.25 no.1
• /
• pp.34-39
• /
• 1987

To study the replication process of the single-stranded DNA parvovirus KBSH-isolated from normal human cell cultures-in actively dividing embryonic swine kidney cells, amount of the synthesized viral hemagglutination (HA) antigen and the overall rate of viral double-stranded replicative form(RF) DNA synthesis were wxamined. The initiation of viral RF KNA synthesis and the decrease of host DNA synthesis rate in viral infected cells occurred almost same time at 15-16 hour post infection(PI). And the release of viral HA antigen to media followed at 24 hour PI, concurrently the overall rate of viral RF DNA synthesis reaching its maximum. Evidence is presented which indicates that successful performance of viral RF DNA replication requires proteins synthesized in viral infected cells at 10-14 hour PI.

• The Korean Journal of Pharmacology
• /
• v.28 no.2
• /
• pp.213-222
• /
• 1992

We investigated effects of several chemical carcinogens, i.e., $benzo({\alpha})pyrene$ (BP),7,12-dimethylbenz(a)anthracene (DMBA), nitrosomethyl urea (NMU), and nicotine on the replication, cytolyticity, DNA synthesis, and protein synthesis of type 1 herpes simplex virus (HSV-1) in viral infected Vero cell monolayers. We observed that the BP and DMBA did not show such activity. All chemical carcinogens did not inhibit the synthesis of viral DNA, but the expression of gamma viral proteins that are expressed from the newly synthesized progeny viral DNA was somewhat notably inhibited by BP and DMBA. However, the synthesis of alpha and beta viral proteins was not altered by the chemical carcinogens. These data indicate that the gamma viral proteins expressed from the newly synthesized DNA in the presence of chemical carcinogens in the culture medium may be defective. This is further supported by the fact that the virus fail to replicate in the presence of these chemical carcinogens, in spite of viral DNA and proteins are somewhat normally synthesized.

• IMMUNE NETWORK
• /
• v.3 no.2
• /
• pp.110-117
• /
• 2003

Background: The usefulness of DNA vaccine at priming step of heterologous prime-boost vaccination led to DNA vaccine closer to practical reality. DNA vaccine priming followed by recombinant viral vector boosting via systemic route induces optimal systemic immunity but no mucosal immunity. Mucosal vaccination of the reversed protocol (recombinant viral vector priming-DNA vaccine boosting), however, can induce both maximal mucosal and systemic immunity. Here, we tried to address the reason why the mucosal protocol of prime-boost vaccination differs from that of systemic vaccination. Methods: To address the importance of primary immunity induced at priming step, mice were primed with different doses of DNA vaccine or coadministration of DNA vaccine plus mucosal adjuvant, and immunity including serum IgG and mucosal IgA was then determined following boosting with recombinant viral vector. Next, to assess influence of humoral pre-existing immunity on boosting $CD8^+$ T cell-mediated immunity, $CD8^+$ T cell-mediated immunity in B cell-deficient (${\mu}K/O$) mice immunized with prime-boost regimens was evaluated by CTL assay and $IFN-{\gamma}$-producing cells. Results: Immunity primed with recombinant viral vector was effectively boosted with DNA vaccine even 60 days later. In particular, animals primed by increasing doses of DNA vaccine or incorporating an adjuvant at priming step and boosted by recombinant viral vector elicited comparable responses to recombinant viral vector primed-DNA vaccine boosted group. Humoral pre-existing immunity was also unlikely to interfere the boosting effect of $CD8^+$ T cell-mediated immunity by recombinant viral vector. Conclusion: This report provides the important point that optimally primed responses should be considered in mucosal immunization of heterologous prime-boost regimens for inducing the effective boosting at both mucosal and systemic sites.

• Korean Journal of Microbiology
• /
• v.43 no.4
• /
• pp.285-291
• /
• 2007

According to the Baltimore Scheme, viruses are classified into 6 main classes based on their replication and coding strategies. Except for some small DNA viruses, most viruses code for their own polymerases: DNA-dependent DNA, RNA-dependent RNA and RNA-dependent DNA polymerases, all of which contain 4 common motifs. We undertook a phylogenetic study to establish the relationship between the Baltimore Scheme and viral polymerases. Amino acid sequence data sets of viral polymerases were taken from NCBI GenBank, and a multiple alignment was performed with CLUSTAL X program. Phylogenetic trees of viral polymerases constructed from the distance matrices were generally consistent with Baltimore Scheme with some minor exceptions. Interestingly, negative RNA viruses (Class V) could be further divided into 2 subgroups with segmented and non-segmented genomes. Thus, Baltimore Scheme for viral taxonomy could be supported by phylogenetic analysis based on the amino acid sequences of viral polymerases.

• BMB Reports
• /
• v.55 no.12
• /
• pp.587-594
• /
• 2022

A persistent DNA tumor virus infection transforms normal cells into cancer cells by either integrating its genome into host chromosomes or retaining it as an extrachromosomal entity called episome. Viruses have evolved mechanisms for attaching episomes to infected host cell chromatin to efficiently segregate the viral genome during mitosis. It has been reported that viral episome can affect the gene expression of the host chromosomes through interactions between viral episomes and epigenetic regulatory host factors. This mini review summarizes our current knowledge of the tethering sites of viral episomes, such as EBV, KSHV, and HBV, on host chromosomes analyzed by three-dimensional genomic tools.

• Korean Journal of Veterinary Research
• /
• v.32 no.3
• /
• pp.389-398
• /
• 1992

Molecular cloning was carried out on the Danish strain of bovine viral diarrhea virus(BVDV) to construct strategy for the diagnostic tools and effective vaccine of BVD afterwards. A recombinant DNA clone(No. 29) was established successfully from cDNA for viral RNA tailed with adenine homopolymer at 3'-end. $^{32}P$-labeled DNA probes of 300~1,800bp fragments, originating from the clone 29, directed specific DNA-RNA hybridization results with BVDV RNA. Recombinant DNA of the clone 29 was about 5,200bp representing 41.6% of the full length of Danish strain's RNA, and restriction sites were recognized for EcoR I, Sst I, Hin d III and Pst I restriction enzymes in the DNA fragment.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.7
• /
• pp.3281-3285
• /
• 2012

Objectives: To evaluate the clinicopathologic correlation and prognostic value of HPV18 DNA viral load in patients with early-stage cervical neuroendocrine carcinoma (NECA). Methods: Formalin-fixed, paraffin-embedded tissue of cervical NECA patients with known HPV18 infection and clinicopathologic data including follow-up results were collected. The HPV18 DNA load was assessed with quantitative PCR targeting the HPV18 E6E7 region. Results: Twenty-one patients with early-stage (IB-IIA) cervical NECA were identified. HPV18 DNA viral load ranged from 0.83 to 55,174 copies/cell (median 5.90). Disease progression, observed in 10 cases (48%), was not significantly associated with any clinicopathologic variables. However, the group of patients with progressive disease tended to have a higher rate of pelvic lymph node metastasis (50% versus 9%, p=0.063) and a lower median value of HPV18 DNA viral load (4.37 versus 8.17 copies/cell, p=0.198) compared to the non-recurrent group. When stratified by a cut-off viral load value of 5.00 copies/cell, the group of patients with viral load ${\leq}5.00$ copies/cell had a significantly shorter disease-free survival than the group with viral load >5.00 copies/cell (p=0.028). The group with a lower viral load also tended to have a higher rate of disease progression (75% versus 31%, p=0.080). No significant difference in the other clinicopathologic variables between the lower and higher viral load groups was identified. Conclusion: HPV18 DNA viral load may have a prognostic value in patients with early-stage NECA of the cervix. A low viral load may be predictive of shortened disease-free survival in these patients.

• Journal of Plant Biology
• /
• v.37 no.3
• /
• pp.349-355
• /
• 1994

Viral RNA was extracted from a purified orchid strain of tobacco mosaic virus (TMV-O) from Cymbidium "Grace Kelly". Polyadenylated viral RNAs were primed with Not I-oligo (dT) primer-adapter. First-strand cDNAs were reversely transcribed by Moloney murine leukaemia virus reverse transcriptase (RNAse H-), and then second-strand cDNAs were synthesized by RNase H and DNA polymerase I. The resulting double-stranded cDNAs were ligated into pSPORT1 vector and transformed into competent E. coli strain JM109 cells. The size of cDNAs within the recombinant plasmids was ranging from 0.9 to 3.9 kb. Among the selected clones, pTMO-0205 and -0210 covered the 3' half and the 5' half of the viral genomic RNA, respectively, which were covering more than 99% of the viral genemo size based on sequencing analysis. Two cDNA fragments which were 3.1 kb BamHI and NotI fragement released from pTMO-0.205 and 3.3 kb SalI and BamHI fragment released from pTMO-0210 were ligated with T4 DNA ligase. The clone was almost entire length, lacking only 31 nucleotides from the 5' terminus based on the sequencing result. This method was shown to be efficiently applicable to other plant viral gnomic RNA for the construction of cDNA.n of cDNA.

• Genomics & Informatics
• /
• v.11 no.3
• /
• pp.121-128
• /
• 2013

The introduction of metagenomics into the field of virology has facilitated the exploration of viral communities in various natural habitats. Understanding the viral ecology of a variety of sample types throughout the biosphere is important per se, but it also has potential applications in clinical and diagnostic virology. However, the procedures used by viral metagenomics may produce technical errors, such as amplification bias, while public viral databases are very limited, which may hamper the determination of the viral diversity in samples. This review considers the current state of viral metagenomics, based on examples from Korean viral metagenomic studies-i.e., rice paddy soil, fermented foods, human gut, seawater, and the near-surface atmosphere. Viral metagenomics has become widespread due to various methodological developments, and much attention has been focused on studies that consider the intrinsic role of viruses that interact with their hosts.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2003.05a
• /
• pp.313-314
• /
• 2003

Antiviral DNA vaccine carrying a gene for a major antigenic viral protein have received considerable attention as a new approach in vaccine development. For fish viruses effects of DNA vaccine encoding viral G gene of infectious hematopoietic necrosis virus(IHNV) and viral hemorrhagic septicemia virus (VHSV)have been demonst.ated previously(Lapatra et al., 2001) Hirame rhabdovirus (HIRRV) causes hemorragic disease on flounder. (omitted)