Inhibition of p53 transcriptional activity by human cytomegalovirus UL44.

Human cytomegalovirus (HCMV) stimulates cellular synthesis of DNA and proteins and induces transition of the cell cycle from G(1) to S and G(2) /M phase, in spite of increased amounts of p53 in the infected cells. The immediate early protein IE2-86  kDa (IE86) tethers a transcriptional repression domain to p53; however, its repression of p53 function is not enough to abrogate the G(1) checkpoint function of p53. Other HCMV proteins that suppress the activity of p53 were investigated in this study.

Role of T lymphocytes in liver abscess formation by Bacteroides fragilis in mice.

The underlying mechanisms of liver abscess formation have not been fully elucidated with regard to the interaction between bacterial virulence factors and the immune response. The objective of this study was to determine the role of the host T cells in liver abscess formation caused by Bacteroides fragilis. We developed a liver abscess mouse model with inoculation of B.

Radiation exposure and cancer incidence in a cohort of nuclear power industry workers in the Republic of Korea, 1992-2005.

This study examines for the first time cancer incidence between radiation and non-radiation workers in nuclear power facilities in the Republic of Korea. Radiation workers were defined as persons who were issued with a dosimeter at nuclear power facilities, until 2005. All analyses were conducted on male workers only (in total 16,236 individuals) because of the sparseness of females.

Human cytomegalovirus IE1-72 protein interacts with p53 and inhibits p53-dependent transactivation by a mechanism different from that of IE2-86 protein.

Infection of host cells with human cytomegalovirus (HCMV) induces cell cycle dysregulation. Two HCMV immediate-early (IE) proteins, IE1-72 and IE2-86, are promiscuous transactivators that have been implicated in the dysregulatory events. Cellular p53 protein is accumulated to high levels in HCMV-infected cells, but the indicative marker of p53 transcriptional activity, p21, is markedly decreased.

Differentiation of mycobacteria in sputa by duplex polymerase chain reaction for mycobacterial hsp65 gene.

Early differentiation of mycobacteria in sputa is crucial. This study was set to evaluate the usefulness of a newly developed duplex polymerase chain reaction (PCR) for hsp65 gene-based method in differentiating mycobacteria in sputum with a positive acid-fast bacilli (AFB) smear before culturing. One hundred forty-seven sputa with positive AFB smear were included for the analysis.

Mycobacterium senuense sp. nov., a slowly growing, non-chromogenic species closely related to the Mycobacterium terrae complex.

A previously undescribed, slowly growing, non-chromogenic mycobacterium, isolated from a Korean patient with a symptomatic pulmonary infection, is described as representing a novel species. Its 16S rRNA gene sequence was unique and phylogenetic analysis based on 16S rRNA gene sequences showed that this organism belonged to the Mycobacterium terrae subclade. Phenotypically, the strain was generally similar to M.

Comparison of full genome sequences between two hepatitis B virus strains with or without preC mutation (A1896) from a single Korean hepatocellular carcinoma patient.

This report describes the full-length sequences of 2 HBV clones from a hepatocellular carcinoma (HCC) patient, one with preC mutation (1896A) and the other without preC mutation. The high level of discrepancy in mutation frequency between these 2 strains was observed in the Core (C) region among 4 ORFs. These data support previous results that Korean HBV strains, belonging to genotype C2, are prone to mutations.

Characterization of two hepatitis B virus populations in a single Korean hepatocellular carcinoma patient with an HBeAg-negative serostatus: a novel X-Gene-deleted strain with inverted duplication sequences of upstream enhancer site II.

Objectives: The aim of the study was to elucidate mutation patterns related to hepatocarcinogenesis in a Korean hepatocellular carcinoma (HCC) patient.

Methods: We analyzed full genome sequences of 6 hepatitis B virus (HBV) clones from an HCC patient.

Results: This patient harbored 2 HBV populations with genomes of different lengths (3,221 and 2,212 bp).

Mycobacterium seoulense sp. nov., a slowly growing scotochromogenic species.

A previously undescribed, slowly growing, scotochromogenic mycobacterium was isolated from a patient with symptomatic pulmonary infection during hsp65 sequence-based identification of Korean clinical isolates. Phenetic characteristics of this strain were generally similar to those of Mycobacterium nebraskense and Mycobacterium scrofulaceum. However, some phenetic characteristics differentiated it from these two species.

Analysis of hepatitis B virus quasispecies distribution in a Korean chronic patient based on the full genome sequences.

Although Korea is a hepatitis B virus (HBV) endemic area, relatively few full-length genome sequences are available. In particular, no comparative analysis has been performed on the full-genome sequences of different HBV quasispecies from a single Korean patient. This report describes the full-length sequences of five HBV clones (two clones with shorter PCR amplicons and three clones with longer amplicons).

Direct application of AvaII PCR restriction fragment length polymorphism analysis (AvaII PRA) targeting 644 bp heat shock protein 65 (hsp65) gene to sputum samples.

To evaluate the usefulness of the AvaII PRA method targeting 644-bp hsp65 gene for the direct detection of pathogenic mycobacteria from clinical specimens, we applied this method to 40 sputum samples and compared the results to those obtained by IS 6110 PCR. Although this method showed a sensitivity slightly lower than IS 6110 PCR (97.5% vs.

Molecular epidemiology of hepatitis B virus (HBV) genotypes and serotypes in patients with chronic HBV infection in Korea.

Objectives: Although hepatitis B virus (HBV) is endemic to Korea, no large-scale survey of HBV genotypes and serotypes based on sequence analysis has been performed.

Methods: In the present study, we genotyped and serotyped HBV strains from 209 patients in two Korean regions, Seoul (107 patients) and Jeju (102 patients), an island off the southeastern Korean coast. Analyses were conducted using the direct sequencing method targeting the partial surface (S) gene (541 bp).

Differentiation of Mycobacterial species by hsp65 duplex PCR followed by duplex-PCR-based restriction analysis and direct sequencing.

Here we describe a novel duplex PCR method which can differentiate Mycobacterium tuberculosis and nontuberculosis mycobacteria (NTM) strains by amplifying hsp65 DNAs of different sizes (195 and 515 bp, respectively). The devised technique was applied to 54 reference and 170 clinical isolates and differentiated all strains into their respective groups with 100% sensitivity and specificity. Furthermore, a duplex PCR-restriction analysis (duplex PRA) and a direct sequencing protocol were developed to differentiate NTM strains at the species and subspecies levels based on previously reported hsp65 DNA sequences (H.

The DNA hybridization assay using single-walled carbon nanotubes as ultrasensitive, long-term optical labels.

Single walled carbon nanotubes (SWNTs) exhibit strong Raman signals as well as fluorescence emissions in the near infrared region. Such signals do not blink or photobleach under prolonged excitation, which is an advantage in optical nano-biomarker applications. In this paper, we present single-stranded DNA conjugated SWNT probes to locate a particular sequence of DNA within a complex genome.

Mechanism of natural rifampin resistance of Streptomyces spp.

In a previous phylogenetic study of the genus Streptomyces using the rpoB gene, N531, which stands for an aspargine residue in position 531 of RpoB instead of serine (S531), known to be associated with natural rifampin resistance in several organisms, was also observed in the RpoB of several Streptomyces species. To determine whether N531 is associated with the rifampin resistance of Streptomyces strains, we analyzed the rifampin minimum inhibitory concentrations (MICs) of 11 strains of the N531 RpoB type (putative rifampin resistant strains) and of 12 strains of the S531 RpoB type. (putative rifampin susceptible strains).

Differentiation of Mycobacterium species by analysis of the heat-shock protein 65 gene (hsp65).

The nucleotide sequences (604 bp) of partial heat-shock protein genes (hsp65) from 161 Mycobacterium strains containing 56 reference Mycobacterium species and 105 clinical isolates were determined and compared. hsp65 sequence analysis showed a higher degree of divergence between Mycobacterium species than did 16S rRNA gene analysis. Generally, the topology of the phylogenetic tree based on the hsp65 DNA sequences was similar to that of the 16S rRNA gene, thus revealing natural relationships among Mycobacterium species.

PCR restriction fragment length polymorphism analysis (PRA)-algorithm targeting 644 bp Heat Shock Protein 65 (hsp65) gene for differentiation of Mycobacterium spp.

A method based on PCR-restriction fragment length polymorphism analysis (PRA) using a novel region of the hsp65 gene was developed for the rapid and exact identification of mycobacteria to the species level. A 644 bp region of hsp65 in 62 mycobacteria reference strains, and 4 related bacterial strains were amplified, and the amplified DNAs were subsequently digested with restriction enzymes, namely, AvaII, HphI, and HpaII. Most of the mycobacteria species were easily differentiated at the species level by the developed method.

Molecular taxonomy of a soil actinomycete isolate, KCCM10454 showing neuroprotective activity by 16S rRNA and rpoB gene analysis.

Epilepsy constitutes a significant public health problem, and even the newest drugs and neurosurgical techniques have proven unable to cure the disease. In order to select a group of isolates which could generate an active compound with neuroprotective or antiepileptic properties, we isolated 517 actinomycete strains from soil samples taken from Jeju Island, in South Korea. We then screened these strains for possible anti-apoptotic effects against serum deprivation-induced hippocampal cell death, using the 3-(4, 5-dimethylthiazol-2-yl)2,5-diphenyl-tetrazolium bromide (MTT) assay as an in vitro test.

Prevalence of naturally occurring surface antigen variants of hepatitis B virus in Korean patients infected chronically.

Although Korea is one of the endemic areas of hepatitis B virus (HBV) infection, the prevalence of naturally occurring variants in the major hydrophilic region (MHR) of the surface (S) gene of HBV has not been determined. In the present study, the prevalence of these variants was examined in terms of the clinical state, and HBeAg serostatus in a large series of Korean patients with chronic HBV infection by direct sequencing analysis of part of the S gene containing the MHR of HBV isolated from 101 chronic HBV patients (51 HBeAg-positive and 50 HBeAg-negative): 37 were asymptomatic carriers, 21 had chronic hepatitis, 20 had liver cirrhosis, and 23 had hepatocellular carcinoma (HCC). Forty-seven MHR variants (46.

Phase variation of biofilm formation in Staphylococcus aureus by IS 256 insertion and its impact on the capacity adhering to polyurethane surface.

While ica gene of Staphylococcus epidermidis is known to undergo phase variation by insertion of IS256, the phenomenon in Staphylococcus aureus has not been evaluated. Six biofilm-positive strains were tested for the presence of biofilm-negative phase-variant strains by Congo red agar test. For potential phase-variant strains, pulsed-field gel electrophoresis was done to exclude the possibility of contamination.

Comparison of full length sequences of hepatitis B virus isolates in hepatocellular carcinoma patients and asymptomatic carriers of Korea.

Relatively few genomic sequences of Korean hepatitis B virus (HBV) isolates are available. Moreover, no comparative study has been made between the full-length genomes of Korean HBV isolates and clinical status. To evaluate mutations in HBV isolates obtained from chronically infected HBV patients in terms of clinical significance, we determined the genomic sequences of HBV isolates obtained from three hepatocellular carcinoma (HCC) patients (He52, He53, and He82) and from three asymptomatic carriers (He74, He100, and He127).

Characterization and applications of CataCleave probe in real-time detection assays.

Cycling probe technology (CPT), which utilizes a chimeric DNA-RNA-DNA probe and RNase H, is a rapid, isothermal probe amplification system for the detection of target DNA. Upon hybridization of the probe to its target DNA, RNase H cleaves the RNA portion of the DNA/RNA hybrid. Utilizing CPT, we designed a catalytically cleavable fluorescence probe (CataCleave probe) containing two internal fluorophores.

IL-6 protects pancreatic islet beta cells from pro-inflammatory cytokines-induced cell death and functional impairment in vitro and in vivo.

Protection of pancreatic islet beta cells from pro-inflammatory cytokines-induced cell death and functional impairment is a key issue in developing therapeutic interventions of type 1 diabetes mellitus including islet transplantation. The effects of IL-6 on the protection of beta cells in vitro and in vivo were examined. Freshly isolated islets or MIN6 beta cells, when pre-incubated with IL-6, showed significantly higher viabilities measured by MTT assay and FACS analysis of PI stained cells against pro-apoptotic signaling delivered by IL-1beta, TNF-alpha and IFN-gamma.

Simultaneous identification of rifampin-resistant Mycobacterium tuberculosis and nontuberculous mycobacteria by polymerase chain reaction-single strand conformation polymorphism and sequence analysis of the RNA polymerase gene (rpoB).

Interspecies variations and mutations associated with rifampin resistance in rpoB of Mycobacterium allow for the simultaneous identification of rifampin-resistant Mycobacterium tuberculosis and nontuberculous mycobacteria by PCR-SSCP analysis and PCR- sequencing. One hundred and ten strains of rifampin-susceptible M. tuberculosis, 14 strains of rifampin-resistant M.

Human cytomegalovirus (HCMV) infection in osteosarcoma cell line suppresses GM-CSF production by induction of TGF-beta.

This study was performed to elucidate the possible mechanism of the disturbance of hemopoiesis by HCMV infection. Saos-2 cells constitutively express mRNA of GM-CSF, and its expression was profoundly decreased by HCMV infection, which required full replication of the virus and was mediated by soluble factors released from the HCMV-infected Saos-2 cells. TGF-beta1 production was statistically and significantly increased from one day after HCMV infection.