• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.14-21
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• 2005

By using PCR with nirS gene primers, three nirSharboring denitrifying bacteria (strain N6, strain N23, and strain R13) were newly isolated from activated sludge of a weak municipal wastewater treatment plant. Small-subunit rRNA gene-based analysis indicated that strain N6, strain N23, and strain R13 were closely related to Arthrobacter sp.,Staphylococcus sp., and Bacillus sp., respectively. In an attempt to identify their roles in biological nitrate and nitrite removal from sewage, we investigated their specific denitrification rates (SDNRs) for $NO_-^3$ - and $NO_-^2$ - in various cultures. All purecultures of each isolated nirS-harboring bacterial strain could remove $NO_-^3$ - and $NO_-^2$ - simultaneously in high efficiency, and the carbon requirements for $NO_-^3$ - removal of strain N6 and strain R13 were effectively low at 3.1 and 4.1 g COD/g $NO_3N$, respectively. In the case of mix-cultures of the strains (N6+N23, N6+R13, N23+R13, and N6+N23+R13), their SDNRs for $NO_-^3$ - were also effective, and their carbon requirements for $NO_-^3$ - removal were also effective at 3.0- 3.8 g COD/g NO3N. However, all tested mix-cultures accumulated $NO_-^2$ - in their culture media. On the other hand, the continuous culture of activated sludge mixed with strain N6 showed no significant increase of $NO_-^3$ - removal in comparison with strain N6's pure culture. These results suggest that nitrate and nitrite removal in biological wastewater treatment might be dependent on complicated bacterial interactions, including several effective denitrifying bacteria isolated in this study, rather than the specific bacterial types present and the number of bacterial types in activated sludge.

• The Korean Journal of Mycology
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• v.23 no.2 s.73
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• pp.190-195
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• 1995

For the screening of biocontrol agents against red-pepper anthracnose (Colletotrichum gloeosporioides Penz) 248 isolates of bacteria, 51 of fungi and 30 of yeasts were obtained from phyllospere of medicinal plants. Of isolated microorganisms, four bacterial isolates, KB6, KB12, KB13 and KB14 were highly antagonistic to C. gloeosporioides than the others through dual culture test on potato dextrose agar (PDA). Among the four bacterial isolates, culture filtrate of the isolate KB12 showed the highest inhibition of C. gloeosporioides on PDA. The culture filtrates of four isolates controlled anthracnose on the red fruits, but not on the green fruits. In the living bacterial cell test, high control effect was observed both on the red and the green fruits. In the biochemical test, all isolates were identified as Bacillus subtilis.

• Journal of Microbiology
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• v.45 no.5
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• pp.394-401
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• 2007

In this study, bacterial communities within the guts of several longicorn beetles were investigated by a culture-dependent method. A total of 142 bacterial strains were isolated from nine species of longicorn beetle, including adults and larvae. A comparison of their partial 16S rRNA gene sequences showed that most of the bacteria constituting the gut communities can typically be found in soil, plants and the intestines of animals, and approximately 10% were proposed as unreported. Phylogenetic analysis demonstrated that the bacterial species comprised 7 phyla, and approximately half were Gammaproteobacteria. Actinobacteria were the second most populous group (19%), followed by Firmicutes (13%) and Alphaproteobacteria (11%). Betaproteobacteria, Flavobacteria, and Acidobacteria were minor constituents. The taxonomic compositions of the isolates were variable according to the species of longicorn beetle. Particularly, an abundance of Actinobacteria existed in Moechotypa diphysis and Mesosa hirsute, which eat broadleaf trees; however, no Actinobacteria were isolated from Corymbia rubra and Monochamus alternatus, which are needle-leaf eaters. Considerable proportions of xylanase and pectinase producing bacteria in the guts of the longicorn beetles implied that the bacteria may play an important role in the digestion of woody diets. Actinobacteria and Gammaproteobacteria were the dominant xylanase producers in the guts of the beetles.

• The Plant Pathology Journal
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• v.36 no.3
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• pp.244-254
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• 2020

Gom-chwi (Ligularia fischeri) is severely infected with Phytophthora drechsleri, the causal organism of Phytophthora root rot, an economically important crop disease that needs management throughout the cultivation period. In the present study, Phytophthora root rot was controlled by using bacterial isolates from rhizosphere soils collected from various plants and screened for antagonistic activity against P. drechsleri. A total of 172 bacterial strains were isolated, of which, 49 strains showed antagonistic activities by dual culture assay. In the seedling assay, six out of the 49 strains showed a predominant effect on suppressing P. drechsleri. Among the six strains, the ObRS-5 strain showed remarkable against P. drechsleri when treated with seed dipping or soil drenching. The ObRS-5 strain was identified as Enterobacter asburiae based on 16S ribosomal RNA gene sequences analysis. The bacterial cells of E. asburiae ObRS-5 significantly suppressed sporangium formation and zoospore germination in P. drechsleri by 87.4% and 66.7%, respectively. In addition, culture filtrate of E. asburiae ObRS-5 also significantly inhibited sporangium formation and zoospore germination by 97.0% and 67.6%, respectively. Soil drenched bacterial cells, filtrate, and culture solution of E. asburiae ObRS-5 effectively suppressed Phytophthora root rot by 63.2%, 57.9%, and 81.1%, respectively. Thus, E. asburiae ObRS-5 could be used as a potential agent for the biological control of Phytophthora root rot infecting gom-chwi.

• The Journal of the Korean Society for Microbiology
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• v.19 no.1
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• pp.41-48
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• 1984

The present study was undertaken to elucidate the antibacterial spectrum of L. casei phage type $J_1$ strain isolated from a fermented milk product against pathogenic enteric bacteria. Growth inhibitory effects and minimum inhibitory concentration(MIC) of culture supernatants of L. casei grown in MRS broth were measured by both plate culture method and microplate broth dilution technique against Salmonella typhi, Salmonella typhimurium, Shigella flexneri, Shigella dysenteriae, enterpathogenic E. coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. The results are summarized as follows: 1. The MRS broth culture of L. casei gave a similar extent of growth inhibitory effects against S. typhi, S. typhimurium, S. flexneri, S. dysenteriae, E. coli, K. pneumoniae and P. aeruginosa, respectively. 2. The inhibitory effects of L. casei culture were observed either in whole broth culture or in culture supernatant, but neither the bacterial suspension nor the neutralized culture supernatant showed such as antibacterial activities. 3. The MIC titres of the culture supernatants were ${\log_2}5$ to ${\log_2}6$, whereas those of the neutralized culture supernatant dropped markdely to ${\log_2}2$ to ${\log_2}3$. These results indicated that major portion of growth inhibitory effects of MRS broth culture of L. casei against enteric bacterial pathogens was possibly due to the acids produced, and minor portion to other antibacterial substances.

• Pediatric Infection and Vaccine
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• v.28 no.2
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• pp.118-123
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• 2021

Culture tests are very important in choosing the appropriate antibiotics for bacterial infections. In some cases, bacteria that could not be identified in standard culture bottles could be detected using blood culture bottles. A previously healthy 13-year-old boy visited our emergency room. He experienced pain, redness, and hardness of periumbilical skin and a fever for five days. There was no history of abdominal surgery and penetrating trauma. Computed tomography showed abscess with cellulitis at the periumbilical soft tissue with no congenital anomaly. Ultrasonography-guided aspiration was performed, and about 8.5 mL of the purulent abscess was aspirated. The abscess was cultured using blood culture bottle. The pus grew Actinomyces radingae and Clostridium ramosum. When performing the pus culture, using blood culture bottles can be more effective and rapid than the standard culture method for the detection of bacterial pathogens.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.3
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• pp.26-33
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• 1997

The bacterial celluloses are very different in its physical, chemical and morphological structures compared to wood cellulose. These fibers have many unique properties that are potentially and commercially beneficial. This study was aimed to elucidate the production of bacterial celluloses and to improve their physical properties by chemical pretreatment. Bacterial celluloses produced by static culture had gel-like pellicle structure. The pellicle thickness was increased with the increasing time, and its layer was about 1.8cm after one-month incubation. The pellicles extruded from the cells of Acetobacter had a non-crystalline structure during initial growing stages, gradually getting crystaliyzed with the incubation time elapse, and eventually fumed to the cellulose I crystals. Young＇s modulus of bacterial cellulose sheet was increased with increasing NaOH concentration, and resulted in the highest at 5% NaOH concentration. Similar results with NaClO3 pretreatment can be observed. Too concentrated alkali solutions induced the destruction of cellulose fibrils and changed the mechanical properties of the sheets. These alkaline pretreatment have removed non-cellulosic components(NCC) from the bacterial cellulose, and enhanced inter-abrillar bonding by direct close contact among cellulosic fibrils.

• Korean Journal of Environmental Biology
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• v.24 no.4
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• pp.307-313
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• 2006

Seasonal variation of marine bacterial community was analyzed in the surface sea water collected from one of the stations locating at Tongyeoung coastal area, Korea. The results obtained by the culture method through identification with the VITEK Microbe ID system after pure culture in the selective medium were compared with those obtained by the DGGE based 16S rRNA PCR method. The composition of the marine bacterial community in the sea water samples harvested in September, 2004, November, 2004, January, 2005, May, 2005 and August, 2005 determined by the culture method showed 5, 5, 4, 6, and 10 strains respectively. Pseudomonas fluorescens and Acinetobacter lwoffii were detected in all seasons. The other strains were identified to be Pseudomonas stutzeri, Sphingomonas paucimobilis, Burkholderia mallei and Chryseobacterium indologenes. In contrast, the 16S rRNA PCR-DGGE method detected 10, 11, 6, 9 and 13 populations respectively in the same sea water samples and the strains were identified to be Acinetobacter lwoffii, Burkholderia mallei, Pseudomonas fluoresence, Actinobacillus ureae, Burkholderia sp., Pseudomonas stutzeri, Roseobacter sp., Vibrio parahaemolyticue, Sphingomonas paucimobilis and Rugeria algocolus. This results indicated that the DGGE based 16S rRNA PCR method was more efficient than the culture method for the grasp of the characteristics of the marine bacterial community.

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.187-194
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• 2015

In this study, L. plantarum, when reacting with the culture media of potential pathogenic bacteria, exhibited an increase in growth rate and antimicrobial activity. In order to examine the characteristics and the nature of the reaction with the bacteria, this study carried out experiments involving culturing the test bacteria in M9 minimal media. Subsequently, the supernatant was incrassated by the decompression-drying method. Through colony forming unit assay, it was confirmed that L. plantarum had the function of growth inhibition to various bacteria. After culturing L. plantarum with bacterial media, the growth rate of L. plantarum was measured by absorbance (OD₆₀₀), the results showed that the growth rate (E. coli treatment group: OD₆₀₀ = 0.848, S. typhimurium treatment group: OD₆₀₀ = 0.848) increased, as compared with the non-treated control group (OD₆₀₀ = 0.48). In contrast, the concentrate itself did not induce the growth of L. plantarum. These results were observed as a universal phenomenon of the Lactobacillus species. Moreover, the increase in antimicrobial activity was observed in L. plantarum, which reacted with the culture media of E. coli and S. typhimurium, through a disc diffusion assay, and the result of growth inhibition against various bacteria was induced. Finally, based on the analysis results of the characteristics of bacteria culture media, which increased the growth rate of L. plantarum and antibacterial activity, the bacterial media had a tolerance for catabolic enzymes, pH 2−8 and heat. Therefore, this substance can be said to be a small molecule which is highly stable under various conditions.

• Archives of Plastic Surgery
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• v.34 no.6
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• pp.691-696
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• 2007

Purpose: The emergency of multi-drug resistant stains of bacteria represents a challenge in the field of plastic surgery. Especially, MRSA(methycillin-resistant Staphylococcus aureus) and Pseudomonas aeruginosa have strong pathogenicity as well as multi-drug resistance so that they have become a lot more problematic strains. This study has been planned to reduce the bacterial burden by applying $Acticoat^{(R)}$(Smith & Nephew Healthcare, Hull, England)dressing into the chronic wounds infected by multi-drug resistant strains and to facilitate their healing. Methods: Nanocrystalline silver dressings($Acticoat^{(R)}$) were applied to chronic wound infected by MRSA or Pseudomonas aeruginosa. Multi-drug resistant bacteria were smeared over a slide glass using sterilized cotton swabs and gram stains were performed directly before and after applying $Acticoat^{(R)}$ dressings at 1, 24, 48 and 72 hours. The gram-stained slides were observed using an optical microscope magnified 1000 times(${\times}1000$). The bacterial counts of the control group(0 hour) were compared to those of the experimental groups(1, 24, 48, and 72 hour). Paired T-test was used to assess a statistical significance. MRSA was cultured in two BAPs(blood agar plate) and two MacConkey plates with streak plate method. None were interventions on one culture plate, while on the other culture plate, $Acticoat^{(R)}$ was placed in a square shape and cultured for 72 hours at $37^{\circ}C$, then plates were examined. Pseudomonas aeruginosa was cultured in the same manner as MRSA. Results: There are the large amount of declination of bacterial counts with statistical significance after $Acticoat^{(R)}$ dressing. The bacteria grew in culture plate without specific intervention, but no bacteria grew in culture plate with applying of $Acticoat^{(R)}$ dressing. Conclusion: We believe that $Acticoat^{(R)}$ dressing could be used as an effective method of treating chronic wounds which are infected by multi-drug resistant organisms.