• The Journal of the Korean Society for Microbiology
• /
• v.3 no.1
• /
• pp.35-41
• /
• 1968

An outbreak of typhoid fever in Samchunpo city was surveyed and the results were summarized as follows: 1. 638 of clinical cases were detected in 17 Dongs(districts) of the city of Samchunpo,(54,064), during the epidemic period from 1st September to the end of November, 1967. 2. The morbidity rate was 1,189 per 100,000 population;(1,300 female, and 1,060 male). 3. The highest peak was reached in the third week of September and a second peak appeared at the end of September 1967. 4. The mode of infection was suspected strongly as a water-borne and the source of infection as an old public well called Gal-Dae-Saim, since the causative agent was found in close public latrine and the contaminated sewage ditch witch was connected with the well. 5. All patients and carriers were treated at their home under the supervision of local medical authorities. 6. The Gal-Dae-Saim was closed immediately on 7th October, 1967 by the order of the mayor. 7. At the end of November, 1967 when the outbreak in Samchunpo was almost ended, another small epidemic occurred in Koseong county which bordered the eastern outskirt of the city. 8. During the survey, a strain of Shigella flexneri was isolated from the sewage located three meters from Gal-Dae-Saim and also from one case. 9. It was reported by the local health center in May, 1968, that no carrier had been detected in the survey made among the persons who had had typhoid fever in 1967. Also thereafter no cases of typhoid fever were reported through October, 1968.

• Journal of Life Science
• /
• v.17 no.3 s.83
• /
• pp.386-395
• /
• 2007

A total of 27 strains of Vibrio parahaemolyticus (18 strains isolated from Korea and 9 strains from Japan) were serotyped and examined for biochemical characteristics, antimicrobial susceptibility patterns, cytotoxicity assay, thermostable direct hemolysin (TDH) production and molecular epidemiology. Using polymerase chain reaction (PCR) method and DNA probe hybridization method, the strains were tested for toxR, tdh, trh and ORF 8 genes. The V. parahaemolyticus isolated from patients were belonged to 8 different serotypes : O3:K6, O1:K38, O3:K57, O4:K9, O4:Kl2, O4:K68, O5:Kl5 and O6:K46. Urease-positive strain possessed the trh gene, and conversely, urease-negative strains lacked the gene, indicating that urease production by V. parahemolyticus strains strongly correlates with the possession of the trh gene. Most strains showed multiple resistant to more than three antibiotics and the antibiogram could be classified into 6 group (I to VI). All of the O3:K6 strains isolated in South Korea and Japan producted TDH at high levels. The TDH titers ranged between 256 and 2.048, and the average titer was 1009. To distinguish the new and increasingly common V. parahaemolyticus strains from clinical isolates, ORF 8 is a useful genetic marker. After Southern hybridization, the HindIII restriction fragment patterns of the tdh gene were grouped one type, respectively. One type showed two bands one of which was 4.3kb and the other was 11.5kb in size. Variation between the O3:K6 serotype are minor when compared to the differences seen with the non O3:K6 strains. The migration patterns of Not I -digested of the total DNA of the O3:K6 strains were similar, and only slight variations were observed between the serotypes. By contrast, the O3:K6 strains and non O3:K6 had markedly different profiles. In conclusion, Random amplified polymorphic DNA (RAPD) profile using appropriate primers was an effective epidemiological marker.

• Microbiology and Biotechnology Letters
• /
• v.38 no.1
• /
• pp.112-115
• /
• 2010

In this study, the antibacterial activity and the moisturizing effect of cream contaning Persicaria hydropiper L. extract were investigated by clinical trial. MIC values of ethyl acetate fraction from Persicaria hydropiper on P.acnes, S.aureus, P.ovale were 0.13~0.25%. The results showed that the antibacterial activity of the ethyl acetate fraction was higher than or equal to the methyl paraben and quercetin. The cream containing the ethyl acetate fraction of Persicaria hydropiper L. extracts was formulated for skin hydration effect. Also, the transepidermal water loss (TEWL) and the water contents in skin were measured. The cream containing Persicaria hydropiper L. extract was applied to the right lower arm. After 180 min, TEWL of parts was decreased as $6.5\;g/m^2h$ (experimental cream) and $7.5\;g/m^2h$ (placebo cream) respectively. And the water contents in skin were increased by 2~4% than the placebo cream. These results indicate that extract/fractions of Persicaria hydropiper L. can function as high potential as bactericide against the skin pathogenic bacteria and the increase of skin hydration of the cream containing extract could be applicable to new functional cosmetics for antiaging.

• Microbiology and Biotechnology Letters
• /
• v.6 no.1
• /
• pp.41-46
• /
• 1978

Piscicidal substance produced by Streptomyces sp. isolated from soil was toxic against various kinds of fish. After extraction with CH$Cl_3$ from the culture medium, the substance was purified by avicel column chromatography. In order to test toxicity, various kinds of fish were subjected to the acqueous solution of 100 us of the substance per liter of water. Generally, the substance was toxic to most fish, but Macropodus chinenes and Misgurnus mizolepis are resistant to the substance than Gobius similis and Pseudorasbora parva. The substance was stable at pH range, 3.0 to 7.0, but labile at alkaline pH, and to heat as well. Succinic dehydrogenase on most of tissue cell of Cyprinus carpio was inhibited by this substance strongly, but spinal cord was not inhibited. By addition of Cu and Pb salts to the culture medium, piscicidal substance producibility was activated.

• Journal of Microbiology and Biotechnology
• /
• v.13 no.6
• /
• pp.841-845
• /
• 2003

In order for engineered tissues to find clinical utility, the engineered tissues must function appropriately. However, smooth muscle (SM) tissues engineered in vitro with a conventional tissue engineering technique may not exhibit contractile functions, because smooth muscle cells (SMCs) cultured in vitro typically revert from a contractile, differentiated phenotype to a synthetic, nondifferentiated phenotype and lose their ability to contract. SMCs in vivo typically reside in mechanically dynamic environments. We hypothesized that cyclic mechanical stretch induces the features of SMCs in in vitro engineered tissues to be similar to those of SMCs in native tissues. To test the hypothesis, aortic SMCs were seeded onto elastic, three-dimensional scaffolds and cultured in vitro under a cyclic mechanical stretching condition for 4 weeks. A significant cell alignment in a direction parallel to the cyclic stretching direction was found in the SM tissues exposed to cyclic stretching. The cellular alignment and alignment direction were consistent with those of native vascular SM tissues, in which SMCs in vivo align in the radial direction (parallel to stretching direction). In control tissues (SM tissues engineered without stretching), cells randomly aligned. The expression of SM ${\alpha}-actin$ and SM myosin heavy chain, phenotypic markers of SMCs in a contractile state, was upregulated in the stretched tissues by 2.5- and 2.0-fold, respectively, compared to SMCs in the control tissues. The cellular features of alignment and contractile phenotype of SMCs in the SM tissues engineered under a mechanically dynamic environment could allow the engineered SM tissues to exhibit contractile functions.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.6
• /
• pp.1179-1185
• /
• 2008

The immune-stimulating activities of Bordetella bronchiseptica antigens containing dermonecrotoxin (BBD) loaded in chitosan microspheres (CMs) have already been reported in vitro and in vivo with a mouse alveolar macrophage cell line (RAW264.7) and mice. Therefore, this study attempted to demonstrate the successful induction of mucosal immune responses after the intranasal administration of BBD loaded in CMs (BBD-CMs) in colostrum-deprived pigs. The BBD was introduced to the CMs using an ionic gelation process involving tripolyphosphate (TPP). Colostrum-deprived pigs were then directly immunized through intranasal administration of the BBD-CMs. A challenge with a field isolate of B. bronchiseptica was performed ten days following the final immunization. The BBD-specific IgG and IgA titers, evident in the nasal wash and serum from the vaccinated pigs, increased with time (p<0.05). Following the challenge, the clinical signs of infection were about 6-fold lower in the vaccinated pigs compared with the nonvaccinated pigs. The grades for gross morphological changes in the turbinate bones from the vaccinated pigs were also significantly lower than the grades recorded for the nonvaccinated pigs (p<0.001). Therefore, the mucosal and systemic immune responses induced in the current study would seem to indicate that the intranasal administration of BBD-CMs may be an effective vaccine against atrophic rhinitis in pigs.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.9
• /
• pp.1559-1567
• /
• 2015

The combination of trimethoprim (TMP) and sulfamethoxazole (SMX) has been shown to be active against Mycobacterium tuberculosis (Mtb) in clinical tuberculosis (TB) treatment. However, the mechanism of action of TMP-SMX against Mtb is still unknown. To unravel this, we have studied the effect of TMP and SMX by deleting the folP2 gene in Mycobacterium smegmatis (Msm), and overexpressing the Mtb and Msm folP1/2 genes in Msm. Knocking out of the folP2 gene in Msm reduced the minimum inhibitory concentration of SMX 8-fold compared with wild type. Overexpression of the folP1 genes from Mtb and Msm increased the MICs by 4- and 2-fold in Msm for SMX and TMP, respectively. We show a strong correlation between the expression of folP1 and folP2 genes and TMP-SMX resistance in mycobacteria. This suggests that a combination of FolP2 inhibitor and SMX could be used for TB treatment with a better outcome.

• Microbiology and Biotechnology Letters
• /
• v.40 no.2
• /
• pp.92-97
• /
• 2012

Antimicrobial peptides (AMPs) are important components of living organisms acting against Gram-negative and Gram-positive bacterial and fungal pathogens. Cathelicidin human peptides have a variety of biological activities that can be used in clinical applications. AMPs are not produced naturally in large quantities, and chemical synthesis is also economically impractical, especially for long peptides. Therefore, as an alternative, heterologous expression of AMPs by recombinant techniques has been studied as a means to reduce production costs. E. coli is an excellent host for the expression of AMPs, as well as other recombinant proteins, because of the low cost involved and its easy manipulation. However, overexpression of AMPs in E. coli has been shown to cause difficulties resulting from the toxicity of the subsequently produced AMPs. Therefore, fusion expression was theorized to be a solution to this problem. In this study, AMPs were expressed as fused proteins with the glutathione S-transferase (GST) binding protein to protect against the toxicity of AMPs when expressed in E. coli. The LL37, and hybrid gaegurin and LL37 (GGN4(1-16)-LL37(17-32), which we designated as GL32, peptides were expressed as GST-fusion proteins in E. coli and the fusion proteins were then purified by affinity columns. The purified peptides were obtained by removal of GST and were confirmed by western blot analysis. The purified antimicrobial peptides then demonstrated antimicrobial activities against Gram-negative and Gram-positive bacterial strains.

• Journal of Microbiology and Biotechnology
• /
• v.21 no.12
• /
• pp.1345-1351
• /
• 2011

Vancomycin therapy failure due to the emergence of tolerance in pneumococci is increasing. The molecular mechanism of tolerance is not clear, but lytA and $pep^{27}$ are known to be involved. Our aim was to evaluate the expression of both genes in vancomycin-tolerant Streptococcus pneumoniae (VTSP) strains. Eleven VTSP strains from a total of 309 clinical isolates of S. pneumoniae from 1997 to 2006 were classified according to the criteria of Liu and Tomasz. All VTSP strains were evaluated for susceptibility according to CLSI criteria, serotype by the Quellung test, and clonality by PFGE. The expressions of lytA and $pep^{27}$ were analyzed in different growth phases by RT-PCR with and without vancomycin. Eighty-two percent of VTSP strains showed resistance to penicillin, and 100% were sensitive to vancomycin and cefotaxime. The most frequent serotypes of VTSP strains were 23F (4/11) and 6B (3/11). Clonal relationship was observed in only two strains. No significant changes were observed in $pep^{27}$ expression in the three phases of growth in VTSP strains with and without vancomycin. Interestingly, $pep^{27}$ expression in the stationary phase in the non-tolerant reference strain R6 was significantly higher. However, no significant differences in lytA expression were observed between VTSP and R6 strains during the phases of growth analyzed. The absence of changes in $pep^{27}$ expression in VTSP strains in the stationary phase may be related to their ability to tolerate high antibiotic concentrations, and thus, they survive and remain in the host under the antibiotic selective pressure reflected in therapeutic failure.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.8
• /
• pp.1076-1083
• /
• 2013

Seventeen compounds derived from traditional Chinese medicines (TCMs) were tested for their antiviral activity against porcine reproductive and respiratory syndrome virus (PRRSV) in vitro. Visualization with the cytopathologic effect (CPE) assay and the 3-(4, 5-dimethyithiazol-2-yl)-2,5-diphenyltetrazolium bromide test were used to determine the 50% cytotoxic concentration ($CC_{50}$) and 50% effective concentration ($EC_{50}$) in cultured Marc-145 cells. Among the tested compounds, chlorogenic acid and scutellarin showed potential anti-PRRSV activity. The $EC_{50}$ values were $270.8{\pm}14.6{\mu}g/ml$ and $28.21{\pm}26.0{\mu}g/ml$ and the selectivity indexes were >5.54 and 35.5, respectively. The time-of-addition and virucidal assay indicated that the anti-PRRSV activity of the two compounds could be due to their inhibiting the early stage of virus replication and/or inactivating the virus directly. The inhibition of the virus attachment was not observed in the adsorption inhibition assay. The inhibition ratios of chlorogenic acid and scutellarin were, respectively, 90.8% and 61.1% at the maximum non-cytotoxic concentrations. The results have provided a basis for further exploration of their antiviral properties and mechanisms in vivo. We believe that the chlorogenic acid and scutellarin have a great potential to be developed as new anti-PRRSV drugs for clinical application.