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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Korean Journal of Microbiology
Journal Basic Information
Journal DOI :
The Microbiological Society of Korea
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Volume & Issues
Volume 37, Issue 4 - Dec 2001
Volume 37, Issue 3 - Sep 2001
Volume 37, Issue 2 - Jun 2001
Volume 37, Issue 1 - Mar 2001
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Microbial Risk Assessment
The Korean Journal of Microbiology, volume 37, issue 2, 2001, Pages 101~108
Risk assessment defines as the process of estimating both the probability that an event will occur and the probable magnitude of its adverse effects. Chemical or microbial risk assessment generally follows four basic steps, that is, hazard identification, exposure assessment, dose-response assessment, and risk characterization. Risk assessment provides an effective framework for determining the relative urgency of problems and the allocation of resources to reduce risks. Using the results of risk analyses, we can target prevention, reme-diation, or control effects towards areas, sources, or situations in which the greatest risk reductions can be achieved with resources available. Risk assessment is also used to explain chemical and microbial risks as well as ecosystem impacts. Moreover, this process, which allows the quantitation and comparison of diverse risks, lets risk managers utilize the maximum amount of complex information in the decision-making process. This information can also be used to weigh the cost and benefits of control options and to develop standards or treatment options.
Proteomic Application in Cell Biology
The Korean Journal of Microbiology, volume 37, issue 2, 2001, Pages 109~113
As the complete genomic sequences accumulate, the use of global techniques became possible. DNA microarray is a powerful technology for measuring global mRNA levels. This method, however, does not provide information on post-translational modifications of proteins. In addition, mRNA levels do not strictly correlate with protein concentrations, especially for lower-abundance proteins. Therefore, studies at the level of transcription are not sufficient to understand cellular activity. Proteomic techniques to analyze protein expression and function at the large-scale have been developed and used. This review introduces a simple explanation for proteomic analysis and examples of how proteomics is applied in cell biology.
Taxonomic Characteristics of Nitrogen-Fixing Oligotrophic Bacteria from Forest Soil
The Korean Journal of Microbiology, volume 37, issue 2, 2001, Pages 114~119
Many isolates from different forest soil layers did not show appreciable growth on full strength of the conventional nutrient broth (NB medium) but grow on its 100-fold dilution (DNB medium). These isolates were divided into four types according to organic nutrient concentration in the growth medium from
dilution of normal NB medium. Oligotrophic bacteria were type II and type IV which grew in
dilution of NB (1 mg C/l) medium. Sixty strains were isolated for obligate oligotrophic bacteria. Chemotaxonomic and phylogenetic characteristics of eleven isolates of acetylene-reducing (nitrogen-fixing) oligotrophic bacteria from forest soil were investigated. They showed similar characteristics: the cellular fatty acid mainly consisted of straight-chain unsaturated
(60-84% of total fatty acids). Ubiquinone Q-10 and a high guanine plus-cytosine content(61-64 mol%) were found. Eleven isolates of nitrogen-fixing oligotrophic bacteria were found to be closely related by full 16S rDNA sequence simility and many common taxonomic traits. Analysis of full 16S rDNA sequences of eleven isolates indicated that they were more closely related to Bradyrhizobium (similarity values: 98.1-98.8%), Agromonas, Nitrobacter, and Afipia.
Attribution of PAH Degradation of Sphingomonas chungbukensis DJ77 to the Plasmid pSY1
The Korean Journal of Microbiology, volume 37, issue 2, 2001, Pages 120~123
Sphingomonas chungbukensis DJ77 is able to use phenanthrene and biphenyl as the sole carbon and energy source. Mitomycin C curing experiment suggested that polyaromatic hydrocarbon (PAH) utilization in strain DJ77 was plasmid-encoded. The plasmid cured strains were failed to grow on the minimal medium sprayed with biphenyl or phenanthrene. This was evident from southern hybridizations using a previously cloned DNA segment as a probe. There were positive signals in the palsmid DNA of the wild-type strain DJ77 and the absence of hybridizations with chromosomal DNA from the plasmid DNA of the wild-type strain DJ77 and the absence of hybridizations with chromosomal DNA from the palsmid-cured mutant strains.
Effect of Salinity on the Bacterial Community in the Sewage Treatment System
The Korean Journal of Microbiology, volume 37, issue 2, 2001, Pages 124~129
For elucidating the effect of salinity to the effect of wastewater treatment, the heterotrophic bacterial numbers, total bacterial numbers, and the bacterial community structure by FISH method were analyzed. The total bacterial numbers were not significantly changed by the salinity. But the heterotrophic bacterial numbers and bacterial community structures were drastically changed by the increase of salinity. In case of 1% salinity, the heterotrophic bacterial numbers and structure were slightly changed comparing to those of contol. In case of 2% and higher salinities, the numbers of heterotrophic bacteria and the proportions of Eubacteria, Proteobacteria
-group and Cytophaga-Flavobacterium groups were deceasing. By these results, the salinity stress to bacterial community in waste water treatment was unveiled, and for sustaining the waste water treatment system, the salinity should be lower than 1%.
Killing Effects of
Photocatalytic System on Microorganisms
The Korean Journal of Microbiology, volume 37, issue 2, 2001, Pages 130~136
The killing effects of two types(one-phase reactor and two-phase reactor) of UV-TiO
photocatalytic system on the microorganisms have been studied. The UV-lamp which emits maximum 39 watts at 254 nm was prepared in these system. Three types of
coating method were adopted. One type is thin film coated form on the quartz tube in the reactor and another one is surface rough coated form on the glass bead. The other one is
-mixed alginate bead form. UV irradiation was carried out for 1 min. In case of one phase reactor, the bactericidal efficiencies of E. coli by
-coated quartz tube and
-coated glass bead were 63.2% and 89.9%, respectively. In the air-bubbling system, the bactericidal efficiency was 95%, however, the efficiency decreased to 90.6% in the non-bubbling system. In the
-mixed alginate bead system, bactericidal efficiency was 86%. When
was treated (10, 15, 20, and 25 mg/ι) to the
-coated glass bead reactor, bactericidal efficiency significantly increased according to the concentration of
. Two phase reactor showed more elevated efficiency. E. coli was more sensitive to the reaction than S. cerevisiae.
Bacterial Diversity in the Mud Flat of Sunchon Bay, Chunnam Provice, by 16S rRNA Gene Analysis
The Korean Journal of Microbiology, volume 37, issue 2, 2001, Pages 137~144
In order to investigate the diversity of bacterial community in the mud flat of Sunchon Bay, Chunnam province, diversity of amplified 16S rDNA was examined. Total DNA was extracted from sediment soils and 16S rDNAs were amplified using PCR primers based on the universally conserved sequences in bacteria. Clonal libraries were constructed and 111 clones were examined by amplified rDNA restriction analysis (ARDRA) using HaeIII. Clones were clustered based on restriction patterns using computer program, GelCompar II. One hundred different RFLP types were detected from 111 clones. The 20 clones were selected and sequenced according to dendrograms derived from ARDRA, to cover most of the bacterial diversity in the clone libraries. None of the clones were identical to any representatives in the Ribosomal Database Project small subunit RNA databases and GenBank. All sequences showed between 77 and 96.8% similarity to the known 16s rRNA sequence from cultured organisms. The 20 clones sequenced fell into seven major lineages of the domain Bacteria: alpha-, delta-, gamma-Proteobacteria, low G+C Gram positive bacteria, high G+C Gram positive bacteria, Sphingobacteria (Cytophaga) and Cyanobacteria (chloroplast). Among the clones, the Proteobacteria were dominant.
Latent Infection and Reactivation of Human Cytomegalovirus from Human Monocyte THP-1 Cells
The Korean Journal of Microbiology, volume 37, issue 2, 2001, Pages 145~150
Reactivation of human cytomegalovirus (HCMV) from latency is often fatal to immunocompromised individuals. To understand the effect of HCMV on human monocytes where HCMV establishes latency, two human monocyte cell lines at different stages in differentiation, THP-1 and HL-60 were infected with HCMV. While the viability and morphology of HL-60 cells were not significantly affected by HCMV, the viability of THP-1 cells was dramatically decreased by HCMV infection. THP-1 cells infected with HCMV became aggregated and adhered to the surface of culture dishes, probably due to the increased expression of adherence molecules CD11b on the infected THP-1 cells. THP-1 cells established a latent HCMV infection were induced to differentiate by treatment with TPA and hydrocortisone. Recovery of infectious HCMV from the culture supernatant of differentiated THP-1 cells was dependent on the time of induction of differentiation after HCMV infection. Thus, in vitro model of reactivation of HCMV from latently infected monocytes was established.
Selection of Lactic Acid Bacteria Specifically Inhibiting the Growth of Helicobacter pylori
The Korean Journal of Microbiology, volume 37, issue 2, 2001, Pages 151~157
This study was conducted to select lactic acid bacteria which possess potential inhibitory effect on Helicobacter pylori, and to make feasibility test of fermented milk products using them. In order to select lactic acid bacteria specifically inhibiting the growth of H. pylori, antibacterial activity using paper disk method, adherence ability to Caco-2 cell inhibitory effect on urease activity of H. pylori, and milk fermentation feasibility were measured. Among 45 strains of lactic acid bacteria tested, 28 strains showed clear zone and Lactobacillus gasseri MK-03 showed the largest clear zone. Caco-2 cell adherence by lactic acid bacteria and inhibitory effect of them on H. pylori adherence were also evaluated. Of 28 strains tested, 18 strains appeared to be effective on adherence to Caco-2 cell, and especially Bifidobacterium longum MK-26 was found to be superior to others. When Bif. longum MK-26 and H. pylori were reacted with Caco-2 cell 2hrs before, adherence percentage of H. pylori decreased from 0.105% to 0.004%. To investigate inhibitory effect of lactic acid bacteria-derived supernatant on urease activity of H. pylori, pH-adjusted fermented supernatant(pH-4.4) was assessed by co-cultivation method. There of Lb. acidophilus MK-07-derived supernatant showed the most inhibitory effect on urease activity of H. pylori. Considering milk fermentation ability of selected 3 strains, they were comparably feasible to fermented milk products. Consequently, Lb. gasseri MK-03, Lb. acidophilus MK-07, and Bif. longum MK-26 were selected to specifically inhibit the growth of H. pylori, by antibacterial activity, inhibition of urease activity, and inhibition of Caco-2 cell adherence, respectively.
Enhanced Production of Avermectin B1a with Streptomyces avermitilis by Optimization of Medium and Glucose Feeding
The Korean Journal of Microbiology, volume 37, issue 2, 2001, Pages 158~163
The effect of phosphate on the production of avermectin B1a was studied. Response surface methodology was applied to optimize the concentration of organic nitrogen sources. The portion of B1b in total avermectins was decreased from 5.8% to 3.0% by the addition of 1.5 g/ι inorganic phosphate to the production medium. Among organic nitrogen sources, soybean meal was the most effective on avermectin biosynthesis. Results showed that B1a productivity was increased by 44.8% in a laboratory scale fermenter cultivation of Streptomyces avermitilis YA99-40 through fed-batch process. A maximal B1a productivity was obtained by repeated 30 and 20 g/ι of glucose feeding at 136 and 206 hour, respectively. The B1a productivity was increased by 86.3% and the proportion of B1a in the total avermectins was improved from 38% to 45% with respect to the control process. These results would be very useful for enhancing productivity of B1a in an up-scaled processes.
Synthesis of 7
-Hydroxycephalosporin C by Immobilized Enzyme
The Korean Journal of Microbiology, volume 37, issue 2, 2001, Pages 164~169
The conversion of cephalosporin C to 7
-hydroxycephalosporin C was examined with the cell-free extract of several cephamycin producing strains. Streptomyces clavuligerus ATCC 27064 was the most potent strain for the activity of cephalosporin 7
-hydroxylase. Partially purified and immobilized cephalosporin 7
-hydroxylase with resins were used to synthesize 7
-hydroxycephalosporin C from the substrate, cephalosporin C. The molecular weight of the product isolated from the reaction mixture were determined to be 431 by ESI-Mass.
NMR also support the conversion of cephalosporin C to 7
-hydroxycephalosporin C by immobilized enzyme.
Enhancement of Xylitol Production Yield by Xylitol Dehydrogenase Defective Mutant of Pichia stipitis
The Korean Journal of Microbiology, volume 37, issue 2, 2001, Pages 170~175
In order to produce xylitol with high yield, experiments were carried out to develope xylitol dehydrogenase(XDH) defective mutant from P. stipitis and to investigate the xylitol fermentation characteristics of mutant strain. After treatment of P. stipitis with EMS, mutant PXM-4 was selected based on te XDH activity and xylitol production capability. Among the tested cosubstrates, galactose was selected as an adequate cosub-strate on xylitol production of mutant PXM-4. But with the increase in the concentration of galactose in the medium, xylitol production was decreased because the transport of xylose into cell was inhibited by galactose. The optimal concentration of galactose for the production of xylitol using 20 g/ι xylose was 20 g/ι Under this condition, maximum concentration of xylitol and yield were 14.4 g/ι and 97%, respectively. In order to prevent the inhibitory effect of xylose transport by galactose, galactose was fed with low concentration and the concentration of xylitol produced was increased up to 25 g/ι.