• Korean Journal of Microbiology
• /
• v.34 no.4
• /
• pp.243-247
• /
• 1998

Comparative analyses of intracellular biopterin contents and its biosynthetic enzymes were performed in Allomyces macrogynus. Biopterin content in fresh weight was 14-fold higher in mycelium than in zoospore. Enzyme activities of GTP cyclohydrolase I and 6-pyruvoyltetrahydropterin synthase in ammonium sulfate fractions were approximately 2-fold higher in mycelium. On the other hand, sepiapterin reductase (SR) activity was 10 fold higher in zoospore. Northern blot assay also demonstrated that SR transcript was abundant in zoospore. These results suggest a possible involvement of tetrahydrobiopterin in cellular differentiation of Allomyces macrogyllus as well as provide an experimental basis to elucidate the physiological function of SR in this organism.

• Korean Journal of Microbiology
• /
• v.33 no.4
• /
• pp.225-231
• /
• 1997

Elastase inhibitor (EI) producing microorganisms were screened by microplate-assay of culture broth using Succinyl-$(Alanine)_3$-Nitroanilide as a chromogenic substrate. The portion of microorganisms showed EI activity above 90% was about 2% of all assayed. Isolated SMF-11 showed relatively high EI activity after filtration using membrane filter of NMWL 3,000. SMF-11 was identified as Streptomyces sp. according to results of morphological or physicochemical identification. SMF-11 has both rectiflexible and spiral spore chains with smooth spore surface and cell wall contained LL-DAP, iso- and anteiso-fatty acids. The amino acids in cell wall were alanine, glutamic acid and glycine. Fifty unit characters for major cluster were tested and the data were analyzed numerically using the TAXON program. The isolate SMF-11 was identified as a strain of Streptomyces lavendulae.

• Korean Journal of Microbiology
• /
• v.49 no.4
• /
• pp.301-308
• /
• 2013

Programmed Death-1 (PD-1) is one of the important immune-inhibitory molecules which was expressed in T cells, B cells, NKT cells, and macrophages activated by various immune activating factors. Lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, is one of the crucial immunogens for PD-1 expression. However, there are only a few reports on the expression mechanisms of PD-1 in innate immune cells. In this study, we investigate the expression mechanisms of PD-1 in LPS-stimulated Raw264.7 cell lines by RT-PCR, Western Blot, flow cytometry as well as ChIP assay and co-immunoprecipitation. When Raw264.7 cells were stimulated with LPS, PD-1 expression was greatly up-regulated via PI3K and p38 signaling. Primary macrophages isolated from LPS-injected mice were also shown the increased expression of PD-1. In promoter assay, NF-${\kappa}B$ and IRF-1 binding regions in mouse PD-1 promoter are important for PD-1 expression. We also found that the co-activation of NF-${\kappa}B$ and IRF-1 is indispensable for the maximum PD-1 expression. These results indicate that the modulation of PD-1 expressed in innate immune cells could be a crucial for the disease therapy such as LPS-induced mouse sepsis model.

• Korean Journal of Microbiology
• /
• v.50 no.2
• /
• pp.95-100
• /
• 2014

Hrq1 is a novel member of RecQ helicase family, found in fungal genomes by bioinformatics analyses. It is most homologous to human RECQL4 and recent genetic and biochemical studies suggested that it may play roles in the maintenance of genome stability. In this study, we investigated yeast two-hybrid interactions between Hrq1 and the yeast genes homologous to the human genes that are known to interact with RECQL4. Among the 11 genes tested, Rad14, a nucleotide excision repair (NER) factor, was found to interact with Hrq1. In addition, pull-down assay with the purified proteins revealed direct protein-protein interaction between Hrq1 and Rad14. The yeast two-hybrid interaction was enhanced by the DNA damage induced by 4-nitroquinoline-1-oxide, which was dependent on the presence of Rad4, a key NER factor. These results suggest that Hrq1 may function in NER through interaction with Rad14.

• Journal of fish pathology
• /
• v.14 no.2
• /
• pp.71-80
• /
• 2001

The purpose of this study was to investigate the microbiological characteristics and the distributions of the bacteria causing streptococcicosis occurred in marine fish farm, Korea. Many kinds of cultures fishes suffered from the disease accompanied with typical symptoms, including darkening of the skin, exophthalmia, petechiae inside of the opercula and distended abdomen. The isolates from the diseased fishes were compared with Lactococcus garvieae by biochmical, biophysical and serological methods and polymerase chain reaction(PCR) assay. We isolated 35 strains of the geuns Streptococcus from the diseased olive flounder, Paralichthys olivaceus, yellow tail, Seriola quinqueradiata and Korean rockfish, Sebastes schlegeli. 15 strains out of the isolates were identified to L. garvieae and the others were not because of their different biochemical and biophysical charateristics. Seven strains of the isolates were agglutinated by rabbit serum raised against L. garvieae $KG^+$ phenotypic cells(ATCC49156)as a reference strain. Twenty-one strains of the isolates identified to L. garvieae since they were formed the expected band through performing PCR assay using specific primers, pLG-1(5'-CATAACAATGAGATCGC-3') and pLG-2(5'-GCACCCCGCGGTTG-3'). In the present study, it showed that L. garvieae was a dominant strain causing streptococcicosis in the tested area due to occurrence of 21 strains as L. garvieae out of all the isolates, 9 atrains as Streptococcus sp. and 5 strains as Enterococcus sp.

• Korean Journal of Microbiology
• /
• v.14 no.2
• /
• pp.75-83
• /
• 1976

Three conmmercial cellulases prepared from Penicillium notatum(cellulalse[K]), Trichoderma viride(cellulase[J]) and Aspergillus niger(cellulase[A]) were nalyzed with respect to their relative purity, activity and the effects of several metal ions on their activities. The activity of cellulase[K] was the strongest of all and that of cellulase[A] being the weaker. The purity of cellulalse[K] was the highest while that of cellulase[J] was the lowest. Under the assay conditions, the optimum concentrations of $Zn^{++}$ and $Mg^{++}$ ions for the activity of cellulase[K] was the highest while that of cellulase[J] was the lowest. Under the assay conditions, the optimum concentrations of $Zn^{++}$ and $Mg^{++}$ ions for the activity of cellulalse[K] was the highest while that of cellulase [A] being weaker. The purity of cellulase[K] was the highest while that of cellulase[J] was the lowest. Under the assay conditions, the optimum concentrations of $Zn^{++}$ and $MG^{++}$ ions for the activity of cellulase[K] were 2 and 7mM while those of cellulase[A] were 5 and 6 mM respectively and those of cellulase[J] were 3mM for both ions. Cellulase[K] and cellulase[J] were more strongly activated by $Zn^{++}$ than $Mg^{++}$ and cellulase[J] by $Mg^{++}$ than $Zn^{++}$. Both $Cu^{++}$ and $Mn^{++}$ ions inhibited by these metal ions. the inhibitory effects of $Mn^{++}$ ions for enzyme activities were stronger than $Cu^{++}$ ions. The Ki values of $Cu^{++}$ and $Mn^{++}$ for cellulase[K] were found to be 6.1 and 0.7mM, those of cellulase[J] were 2.6 and 0.32 mM, and those of cellulalse[A] were 2.0 and 0.2 mM respectively. Both $Cu^{++}$ and $Mn^{++}$ ions showed a pattrn of competitive inhibition of the enzyme activity. When Na-CMC was used as substrate, the Km and V values of celluase [K] were calculated to be $2.0{\times}10^{-4}mM$ and 3.43mmoles/hour, those of cellulase[J] were $2.4{\times}10^{-4}mM$ and 3.77mmoles/hour, and those of cellulase[A] were $4.0{\times}10^{-4}mM$ and 4.00mmoles/hour respectively.

• Korean Journal of Microbiology
• /
• v.42 no.3
• /
• pp.199-204
• /
• 2006

Streptococcosis of olive flounder(Paralichthys olivaceus) is an important bacterial disease in Jeju island. In this study, we investigated monthly infection pattern of this disease in different size of the flounder fish. Even though the disease occurred throughout the year, the infection ratio was relatively higher in the months with warm water season. The infection was more prevalent in adult flounder over 30 cm total length compare to these of small size fish. Two infectious species of streptococcosis pathogens were detected by multiplex PCR assay. Detection ratios of Streptococcus iniae and S. parauberis reached up to 46% and 54%, respectively, from June 2003 to May 2005 in Jeju island. S. iniae occurred intensively from September to October, whereas S. parauberis reported from March to May. S. iniae and S. parauberis infections of cultured flounder share some common features, but clinical findings showed considerable differences between two diseases. Distended abdomen, protruded anus and ascitic fluid in the peritoneal cavity are evident lesions detected in S. iniae infection, whereas, flounders infected by S. parauberis showed prominent lesions such as darkened surface and haemorrhaging in the non-ocular side. Both streptococcosis pathogens were sensitive to antibiotics, such as ampicillin and amoxicillin. However, S. iniae strains were more sensitive to doxycycline, erythromycin and oxytetracycline than S. parauberis strains.

• Korean Journal of Microbiology
• /
• v.41 no.4
• /
• pp.275-280
• /
• 2005

Anthrax is an infectious disease caused by the gram-positive bacterium, Bacillus anthracis. Anthrax toxin is a tripartite toxin comprising of protective antigen (PA), lethal factor (LF) and edema factor (EF). PA is the receptor-binding component, which facilitates the entry of LF or EF onto the cytosol. LF is a zinc-dependent metalloprotease, which is a critical virulence factor in cytotoxicity of infected animals. Therefore, it is of interest to develop its potent inhibitors for the neutralization of anthrax toxin. The first step to identify the inhibitors is the development of a rapid, sensitive, and simple assay method with a high-throughput ability. Much efforts have been concentrated on the preparation of powerful assays and on the screening of inhibitors using these system. In the present study, we have tried to construct anthrax lethal factor in yeast expression system to prepare cell-based high-throughput assay system. Here, we have shown the results covering the construction of a new vector system, subcloning of LF gene, and the expression of target gene. Our results are first trial to express LF gene in eukaryote and provide the basic steps in design of cell-based assay system.

• Korean Journal of Microbiology
• /
• v.55 no.3
• /
• pp.181-190
• /
• 2019

In Escherichia coli, DicA protein is involved in cell division control. DicA protein is known to bind DNA better at $25^{\circ}C$ than at $37^{\circ}C$. However, the molecular cause of the temperature dependent binding is not clear. In this study, we investigated how DicA binds DNA and why its DNA binding activity depends on temperature. An unique in vivo DNA binding assay developed in this laboratory showed that unlike the homologous proteins such as RovA or SlyA, DicA uses its N-terminal domain for DNA binding. The in vivo DNA binding assay of DicA also demonstrated that the temperature-dependent DNA binding activity does not come from Cnu or H-NS that is known to bind DNA better at $25^{\circ}C$ than at $37^{\circ}C$. Electrophoretic Mobility Shift Assay (EMSA), when performed with purified DicA protein, did not show temperature-dependent DicA binding activity. However when EMSA was performed with crude protein from WT E. coli cells, temperature-dependent DicA binding activity was observed, suggesting that there is a factor(s) that confers temperature DNA binding activity of DicA in vivo.

• Journal of the Korean Society of Radiology
• /
• v.82 no.6
• /
• pp.1524-1533
• /
• 2021

Purpose To investigate the incidence of tuberculosis (TB) in healthcare workers (HCWs) with positive interferon-gamma release assay (IGRA) results based on chest X-ray (CXR) and CT findings and determine the role of imaging in the diagnosis of TB. Materials and Methods Among 1976 hospital personnel screened for TB using IGRA, IGRApositive subjects were retrospectively investigated. Clustered nodular and/or linear streaky opacities in the upper lung zone were considered positive on CXR. The CT findings were classified as active, indeterminate, inactive, or normal. The active or indeterminate class was considered CT-positive. Results IGRA was positive in 255 subjects (12.9%). CXR and CT were performed in 249 (99.2%) and 113 subjects (45.0%), respectively. CXR- and CT-positive findings were found in 7 of 249 (2.8%) and 9 of 113 (8.0%) patients, respectively. Among the nine CT-positive subjects, active and indeterminate TB findings were found in 6 (5.3%) and 3 (2.7%) patients, respectively. Microbiological tests, including acid-fast bacilli staining, culture, and polymerase chain reaction for TB, were negative in all nine CT-positive subjects. Empirical anti-TB medications were administered to 9 CT-positive subjects, and 3 of these nine subjects were CXR-negative for pulmonary TB.