• Mycobiology
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• 제34권2호
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• pp.67-72
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• 2006

Efficacy of resistance induction by the bacterial isolates Pseudomonas putida (TRL2-3), Micrococcus luteus (TRK2-2) and Flexibacteraceae bacterium (MRL412), which were isolated from the rhizosphere of plants growing in Jeju Mountain, were tested in a greenhouse. The disease severity caused by Phytophthora infestans was effectively reduced in the potato plants pre-inoculated with bacterial isolates compared with those of the untreated control plants growing in a greenhouse. In order to estimate the level of protection by the bacterial isolates, Mancozeb WP (Diesen $M^{(R)}$, Kyong nong) and DL-3-amino butyric acid (BABA) were pre-treated, whereas Dimethomorph WP ($Forum^{(R)}$, Kyong nong) and phosphonic acid ($H_{3}PO_{3}$) were post-treated the challenge inoculation with the pathogen. Disease severities of chemical pre-treated as well as post-treated plants were reduced compare to those of the untreated. The disease reduction in the plants pre-treated with Mancozeb WP was the highest, whereas that of post-treated with Dimethomorph WP was the lowest. The yields of plants pre-inoculated with three bacterial isolates were greatly increased than those of control plants. These results suggest that biological control by bacterial isolates might be an alternative strategy against late blight disease in potato plants growing in greenhouse.

• 한국동물학회:학술대회논문집
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• 한국동물학회 2000년도 한국생물과학협회 학술발표대회
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• pp.131.2-132
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• 2000

No Abstract, See Full Text

• 한국환경농학회지
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• 제37권2호
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• pp.146-149
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• 2018

아셀렌산염(selenite, ${SeO_3}^{2-}$)을 환원시키는 세균 SE4-1을 복합 산업단지 내 위치한 오염된 하천 퇴적토로부터 분리하였고, 계통분석결과 이 균주는 Citrobacter freundii와 가장 유사하였다. 이 균주는 혐기적 환경에서 아셀렌산염을 원소상 셀레늄(elemental selenium, $Se^0$)으로 환원시켰고, 그 형상은 구형으로 확인되었다. 이러한 고체상의 침전은 셀레늄 산소음이온의 이동성을 줄이고 생물가용성을 줄여, 생태계 독성을 줄이는 잠재성을 제시해 줄 수 있을 것이다.

• 자원환경지질
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• 제43권3호
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• pp.223-233
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• 2010

세포외 중합체(EPS)의 존재 유무에 따라 Pseudomonas aeruginosa가 용존 비소, 크롬, 우라늄의 흡착 및 산화상태의 변화에 미치는 영향을 회분식 실험을 통해 조사하였다. 배양한 미생물의 표면을 세척한 것과 세척하지 않은 것으로 구분하여 무영양 상태에서 1.1 mg/L의 As(V)와 Cr(VI), 0.5 mg/L의 U(VI)와 반응시키며 시간에 따라 각각의 총 용존 함량과 산화상태 변화를 측정하였다. As(V)의 경우 EPS 존재 여부와 관계없이 흡착은 발생하지 않았으나 EPS가 보존된 박테리아는 As(V)의 약 60%를 As(III)로 환원하였다. 표면을 세척하지 않은 박테리아는 총 용존 크롬의 45%를 제거하였으며 잔류된 용존 크롬의 64%를 Cr(III)로 환원하였다. 우라늄의 경우, 박테리아 표면을 세척하지 않았을 때 U(VI)의 약 80% 이상이 용액으로부터 제거되었다. 이러한 원소 환원은 박테리아가 분비한 EPS 자체의 환원 능력 또는 EPS로부터 보호받아 생육성이 보존된 박테리아의 해독성 환원에 의한 것으로 여겨진다. 이 연구 결과는 자연 환경에서 대부분 바이오필름 상태로 존재하는 미생물이 비소, 크롬, 우라늄의 산화상태 및 이동도 조절에 지대한 영향을 미칠 수도 있음을 의미한다.

• The Plant Pathology Journal
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• 제29권4호
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• pp.418-426
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• 2013

Pseudomonas isolates from different crop plants were screened for in vitro growth inhibition of Phytophthora capsici and production of biosurfactant. Two in vivo experiments were performed to determine the efficacy of selected Pseudomonas strains against Phytophthora blight of pepper by comparing two fungicide treatments [acibenzolar-S-methyl (ASM) and ASM + mefenoxam]. Bacterial isolates were applied by soil drenching ($1{\times}10^9$ cells/ml), ASM ($0.1{\mu}g$ a.i./ml) and ASM + mefenoxam (0.2 mg product/ml) were applied by foliar spraying, and P. capsici inoculum was incorporated into the pot soil three days after treatments. In the first experiment, four Pseudomonas strains resulted in significant reduction from 48.4 to 61.3% in Phytophthora blight severity. In the second experiment, bacterial treatments combining with olive oil (5 mL per plant) significantly enhanced biological control activity, resulting in a reduction of disease level ranging from 56.8 to 81.1%. ASM + mefenoxam was the most effective treatment while ASM alone was less effective in both bioassays. These results indicate that our Pseudomonas fluorescens strains (6L10, 6ba6 and 3ss9) that have biosurfactant-producing abilities are effective against P. capsici on pepper, and enhanced disease suppression could be achieved when they were used in combination with olive oil.

• Journal of Periodontal and Implant Science
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• 제48권6호
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• pp.373-382
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• 2018

Purpose: The aim of this study was to evaluate the effects of various prophylactic treatments of titanium implants on bacterial biofilm formation, correlating surface modifications with the biofilms produced by Pseudomonas aeruginosa PAO1, Staphylococcus aureus, and bacteria isolated from saliva. Methods: Pure titanium disks were treated with various prophylactic procedures, and atomic force microscopy (AFM) was used to determine the degree to which surface roughness was modified. To evaluate antibiofilm activity, we used P. aeruginosa PAO1, S. aureus, and saliva-isolated Streptococcus spp., Bacteroides fragilis, and Staphylococcus epidermidis. Results: AFM showed that the surface roughness increased after using the air-polishing device and ultrasonic scaler, while a significant reduction was observed after using a curette or polishing with Detartrine ZTM (DZ) abrasive paste. In addition, we only observed a significant (P<0.01) reduction in biofilm formation on the DZ-treated implant surfaces. Conclusion: In this study, both AFM and antibiofilm analyses indicated that using DZ abrasive paste could be considered as the prophylactic procedure of choice for managing peri-implant lesions and for therapy-resistant cases of periodontitis.

• Asian-Australasian Journal of Animal Sciences
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• 제16권6호
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• pp.852-862
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• 2003

An experiment was conducted to study the effect of ionophore enriched cold processed mineral block supplemented with urea molasses on microbial growth and rumen fermentation. Twelve adult male crossbred cattle were divided into four groups on body weight basis. Animals were given wheat straw as a basal diet. The animals of group I and II were supplemented with concentrate mixture and animals of group III and IV were supplemented with cold processed urea molasses mineral block (UMMB). Thirty mg monensin/day/animal were supplemented to the animals of group II and 35 ppm monensin were incorporated in the UMMB supplemented to the animals of group IV. Dry matter (DM) intake did not differ significantly among groups. Mean rumen pH was higher in UMMB fed animals. Total volatile fatty acids (TVFA) concentration (mmole/L strained rumen liquor (SRL) in group III (113.19) was significantly (p<0.05) higher than those of group I (105.83) and II (108.74) but similar to group IV (109.34). TVFA production (mole/day) was similar in all the groups. The molar proportion of acetate was significantly (p<0.01) higher in the group I (59.56) than those of group II (51.73) and IV (55.91) but similar to group III (57.12). The molar proportion of propionate was significantly (p<0.01) higher in the monensin treated groups i.e. group II (38.38) and IV (36.26) than those of group I (27.78) and III (33.06). Butyrate molar percent was significantly (p<0.01) higher in group I (12.65) than those of group II (10.19), group III (9.83) and IV (7.84). The reduction of acetate and butyrate was due to UMMB and monensin resulted in lower A:P ratio. Average bacterial pool and bacterial production rate did not differ significantly among groups. Total N concentration (mg/100 ml SRL) was significantly (p<0.01) higher in the group I (55.30) and III (57.70) as compared to the group II (47.97) and IV (47.59). Ammonia-N concentration (mg/100 ml SRL) of group III (34.99) was significantly (p<0.01) higher than that of the group I (25.76) which was again significantly (p<0.01) higher than that of the group II (20.79) and IV (19.83) indicating slower release of ammonia due to monensin in diet. Total bacterial, cellulolytic, proteolytic bacterial and fungal count at 4 h post feeding did not differ significantly (p<0.05) among treatment groups. However, methanogenic bacterial count was significantly (p<0.01) higher in the group I (11.80) compared to the group II (8.43) which was significantly (p<0.01) higher than that of the group III (4.70) and IV (2.90). Average protozoal population was affected by both treatments. Thus feeding of UMMB and monensin in diet affected the rumen fermentation pattern towards propionate production, slower release of ammonia and reduction in methanogenic bacteria in the rumen.

• Journal of Periodontal and Implant Science
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• 제47권4호
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• pp.219-230
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• 2017

Purpose: The purpose of this study was to compare the characteristics of single- and dualspecies in vitro oral biofilms made by static and dynamic methods. Methods: Hydroxyapatite (HA) disks, 12.7 mm in diameter and 3 mm thick, were coated with processed saliva for 4 hours. The disks were divided into a static method group and a dynamic method group. The disks treated with a static method were cultured in 12-well plates, and the disks in the dynamic method group were cultured in a Center for Disease Control and Prevention (CDC) biofilm reactor for 72 hours. In the single- and dual-species biofilms, Fusobacterium nucleatum and Porphyromonas gingivalis were used, and the amount of adhering bacteria, proportions of species, and bacterial reduction of chlorhexidine were examined. Bacterial adhesion was examined with scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Results: Compared with the biofilms made using the static method, the biofilms made using the dynamic method had significantly lower amounts of adhering and looser bacterial accumulation in SEM and CLSM images. The proportion of P. gingivalis was higher in the dynamic method group than in the static method group; however, the difference was not statistically significant. Furthermore, the biofilm thickness and bacterial reduction by chlorhexidine showed no significant differences between the 2 methods. Conclusions: When used to reproduce periodontal biofilms composed of F. nucleatum and P. gingivalis, the dynamic method (CDC biofilm reactor) formed looser biofilms containing fewer bacteria than the well plate. However, this difference did not influence the thickness of the biofilms or the activity of chlorhexidine. Therefore, both methods are useful for mimicking periodontitis-associated oral biofilms.

• 한국식품과학회지
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• 제12권4호
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• pp.272-277
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• 1980

본 연구는 유용 세균의 포자를 정제화(tabletting)하는 과정에서 포자의 내구성 특히 타정 압력에 대한 세균 포자의 파괴율을 규명하려 하였다. Bacillus coagulans, Bacillus subtilis 및 Clostridium butyricum의 세가지 포자 형성균의 포자와 포자를 형성하지 않는 세균인 Streptococcus faecalis의 영양세포에 대하여 시험하였다. 정제제조 과정에서 포자의 파괴는 주로 타정과정에서 일어나며 세균의 포자는 타정압력에 대하여 대수적 파괴율을 나타내었다. 세균포자의 압력에 의한 파괴율은 세균의 종류에 따라 달라지며 이것을 정량적으로 나타내기 위하여 Decimal Reduction Pressure라는 개념을 도입하여 P-value라 칭하고 각 세균 포자의 P-value를 구하였든 바 B. subtilis의 포자는 $2.9\;ton/cm^2$, B. coagulans의 포자는 $2.6\;ton/cm^2$, Cl. butyricum의 포자는 $2.1\;ton/cm^2$의 값을 각각 나타내었다. 반면, Str. faecalis의 영양세포는 $1.7\;ton/cm^2$의 낮은 값을 나타내었다. 세균포자의 파괴율은 사용하는 부형제에 따라 영향을 받았으며 동일한 B. coagulans의 포자라도 lactose filler에서는 그 P-value가 $2.8\;ton/cm^2$이었으며 starch filler에서는 $2.0\;ton/cm^2$이었다. 동일한 부형제를 사용하였을 때 생존 포자수는 정제의 경도와 밀도에 역비례하였다. 그러나 경도와 밀도가 낮은 starch filler에서는 lactose filler에 비교하여 더 높은 포자 파괴율을 보였다. 결론적으로 부형제의 종류는 정제 형성뿐만 아니라 세균 포자의 생존에도 중요한 요인이며, 물리적 성질이 서로 다른 부형제를 알맞게 혼합함으로서 타정시 유용세균포자의 생존율을 크게 향상시킬 수 있다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권3호
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• pp.202-205
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• 2010

Introduction: The aim of the present study was to investigate the effect of mechanical irrigation in combination with mouthwash of antimicrobial agents on salivary bacterial counts. Materials and Methods: This study was performed with a randomized study employing a panel of 40 healthy volunteers (20 males and 20 females) between the age of 26 and 32 years. Volunteers were randomly put in one of four treatment groups. In the first group, 0.2 mL of non-stimulatory saliva was collected from every subjective person. Then, saliva was collected after rinsing with chlorhexidine (CHX) for 1 minute. In the second group, non-stimulatory saliva was collected, and then saliva was collected after rinsing with CHX and irrigation with saline. In the third and fourth groups, the same procedures as the first and second groups were performed with povidone iodine (PVI) instead of CHX. All of these samples were cultured for 48 hours aerobically. The reduction rates of colony-forming units (CFU) were calculated for each group. The reduction rate between each group was tested statistically using student t-test. Results: Using CHX in combination with saline irrigation showed a significant decrease of the salivary bacterial CFU when compared with only using CHX.(P<0.01) And using PVI with saline irrigation showed a little decrease of the CFU when compared with only using PVI, but there was no statistical significance.(P>0.01) Conclusion: It was concluded that the CHX or PVI used with saline irrigation made the salivary bacterial counts reduced more than when CHX or PVI was used alone as an oral antiseptic agent.