• Asian-Australasian Journal of Animal Sciences
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• 제22권1호
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• pp.131-138
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• 2009

Among rumen microbes, bacteria play important roles in the biological degradation of plant fiber due to their large biomass and high activity. To maximize the utilization of fiber components such as cellulose and hemicellulose by ruminant animals, the ecology and functions of rumen bacteria should be understood in detail. Recent genome sequencing analyses of representative fibrolytic bacterial species revealed that the number and variety of enzymes for plant fiber digestion clearly differ between Fibrobacter succinogenes and Ruminococcus flavefaciens. Therefore, the mechanism of plant fiber digestion is also thought to differ between these two species. Ecology of individual fibrolytic bacterial species has been investigated using pure cultures and electron microscopy. Recent advances in molecular biology techniques complement the disadvantages of conventional techniques and allow accurate evaluation of the ecology of specific bacteria in mixed culture, even in situ and in vivo. Molecular monitoring of fibrolytic bacterial species in the rumen indicated the predominance of F. succinogenes. Nutritive interactions between fibrolytic and non-fibrolytic bacteria are important in maintaining and promoting fibrolytic activity, mainly in terms of crossfeeding of metabolites. Recent 16S rDNA-based analyses suggest that presently recognized fibrolytic species such as F. succinogenes and two Ruminococcus species with fibrolytic activity may represent only a small proportion of the total fibrolytic population and that uncultured bacteria may be responsible for fiber digestion in the rumen. Therefore, characterization of these unidentified bacteria is important to fully understand the physiology and ecology of fiber digestion. To achieve this, a combination of conventional and modern techniques could be useful.

• Journal of Microbiology
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• 제42권1호
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• pp.1-8
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• 2004

Changes in the bacterial populations of a 5-stage biological nutrient removal (BNR) process, with a step feed system for wastewater treatment, were monitored by denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA fragments. DGGE analysis indicated seasonal community changes were observed, however, community profiles of the total bacteria of each reactor showed only minor differences in the samples obtained from the same season. The number of major bands was higher in the summer samples, and decreased during the winter period, indicating that the microbial community structure became simpler at low temperatures. Since the nitrogen and phosphate removal efficiencies were highly maintained throughout the winter operation period, the bacteria which still remaining in the winter sample can be considered important, playing a key role in the present 5-stage BNR sludge. The prominent DGGE bands were excised, and sequenced to gain insight into the identities of the predominant bacterial populations present, and most were found to not be closely related to previously characterized bacteria. These data suggest the importance of culture-independent methods for the quality control of wastewater treatment.

• Journal of Oral Medicine and Pain
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• 제21권1호
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• pp.123-131
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• 1996

Bacteremia occurs in a wide variety of clinical procedures in oral cavity. Reduction of the number of causative microorganisms of infective endocarditis in oral cavity by local administration of antimicrobial agents decreases the magnitude of bacteremia and possibility of infective endocarditis. The effects of chlorhexidine on Streptococcus sanguis, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, Streptococcus gordonii, Staphylococcus aureus, and Staphylococcus epidermis were investigated by measurement of turbidity. The effects of 0.1% chlorhexidine gargling for 7 days on oral bacterial flora, total streptococci, S. mutans, S. aureus, and S. epidermis in whole saliv a of 7 healthy human subjects, were investigated by measurement of Colony Forming Units (CFU). The obtained results were as follows : 1. Chlorhexidine showed significant antimicrobial effects on Streptococcus snaguis, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, Streptococcus gordonii, Staphylococcus aureus, and Staphylococcus epidermis. However, the effects on S. sanguis and S. gordonii were not apparent compared with other microorganisms. 2. Oral gargling of 0.1% chlorhexidine decreased the CFU values of normal oral bacterial flora, total streptococci, S. mutans, S. aureus, and S. epidermis in whole saliva. The antimicrobial effects were significant after 4 days of chlorhexidine gargling. 3. Local antimicrobial administration in addition to systemic antibiotic prophylaxis can be highly recommended as an effective adjunct regimen for prevention of infective endocarditis.

• Journal of Microbiology and Biotechnology
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• 제20권9호
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• pp.1339-1347
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• 2010

In this study, the identity and distribution of plants and the structure of their associated rhizobacterial communities were examined in an oil-contaminated site. The number of plant species that formed a community or were scattered was 24. The species living in soil highly contaminated with total petroleum hydrocarbon (TPH) (9,000-4,5000 mg/g-soil) were Cynodon dactylon, Persicaria lapathifolia, and Calystegia soldanella (a halophytic species). Among the 24 plant species, the following have been known to be effective for oil removal: C. dactylon, Digitaria sanguinalis, and Cyperus orthostachyus. Denaturing gradient gel electrophoresis (DGGE) profile analysis showed that the following pairs of plant species had highly similar (above 70%) rhizobacterial community structures: Artemisia princeps and Hemistepta lyrata; C. dactylon and P. lapathifolia; Carex kobomugi and Cardamine flexuosa; and Equisetum arvense and D. sanguinalis. The major groups of rhizobacteria were Beta-proteobacteria, Gamma-proteobacteria, Chloroflexi, Actinobacteria, and unknown. Based on DGGE analysis, P. lapathifolia, found for the first time in this study growing in the presence of high TPH, may be a good species for phytoremediation of oil-contaminated soils and in particular, C. soldanella may be useful for soils with high TPH and salt concentrations. Overall, this study suggests that the plant roots, regardless of plant species, may have a similar influence on the bacterial community structure in oil-contaminated soil.

• 농업과학연구
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• 제37권3호
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• pp.405-412
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• 2010

This study was focused on finding the potential of hot water extract of bamboo shoot (Sasa borealis Makino) on the fermentation of Kimchi made with Chinese cabbage. The properties of Kimchi were examined up to 28 days of storage. The pH and acidity decreased regardless of treatments and showed no significant difference between treatments. There was a decreasing tendency of both total and reducing sugars in kimchi but the addition of bamboo extract did not affect the soluble sugar levels. Interestingly, bamboo extracts affected the lactic acid fermentation and ripening, resulting in the increase of lactic acid in bamboo extract treatment. Number of total bacterial cell of additive group is higher than control one, probably due to the stimulative effect of bamboo extract on bacterial growth. Level of lactic acid bacteria was also higher in the additive group, thus, it is considered that bamboo extract appeared to enhance the proliferation of lactic acid bacteria. The acceptability of treated Kimchi was higher in general. And results of intensity evaluation in color and texture were higher as well by addition of bamboo extract.

• 미생물학회지
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• 제37권1호
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• pp.85-91
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• 2001

생물학적 방법으로 토착 미생물에 의해 벤젠과 톨루엔을 효과적으로 분해할 수 있는 토양환경인자의 조건을 조사하기 위해 16가지의 서로 다른 환경의 미소환경(microcosm)을 제작하여 벤젠과 톨루엔 분해실험을 수행하였고, 아울러 분해과정에서 토착미생물의 분포변화를 조사하였다. 그 결과 실험 조건중 토양의 수분 포화도는 30%와 60%이면서 동시에 생물들이 흡착할 수 있는 미생물 흡착제로 활성탄을 1% 첨가한 미소환경(Case 6, Case 7)에서 벤젠과 톨루엔의 분해속도가 가장 빨랐다. 토착토양미생물의 분포변화를 조사한 결과 벤젠과 톨루엔의 분해가 가장 빨리 일어나는 Case 6 와 Case 7에서는 10일 배양 후 total culturable bacteria는 초기 세균 수에 비해 각각 488배와 308배가 증가하였다. 벤젠과 톨루엔 분해세균의 증가 역시 총 세균수가 증가하는 비율로 증가하여 초기 분포를 계속 유지하였고, 벤젠과 톨루엔을 첨가한 미소환경에서 분해 미생물 종의 변화는, 첨가 전 그람음성 세균이 반응 10일 후에는 그람양성 세균이 탈이 분리되었다.

• 한국버섯학회지
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• 제7권4호
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• pp.168-172
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• 2009

We attempted to isolate the bacterial strains from the fruiting bodies of Agaricus brazilensis and determined their effects on browning and distortions of mushrooms. No bacterial strains were isolated when the middle of browning regions of A. brazilensis were used. Total 125 bacterial strains were obtained from the surface of browning regions and classified into 17 different genera and 29 species by using MIDI methods. Most common genus were Pseudomonas (26), Yersinia (29), and Cedecea (29). High lytic activity were detected when Pseudomonas strains were tested, while relatively low lytic activity were observed with both Yersinia and Cedecea strains.Therefore, we believed the distortion of mushroom could be the result of bacterial infections. Also, the development of brownish color was detected in large number of A. brazilensis strains only by incubation at 4C, suggesting no specific correlation between bacterial strains and brownish color development. Also, it is considered that the development of brownish color can be the normal changes of A. brazilensis.

• Journal of Microbiology
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• 제43권3호
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• pp.219-227
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• 2005

Little is known about the bacterial communities associated with the plants inhabiting sand dune ecosystems. In this study, the bacterial populations associated with two major sand dune plant species, Calystegia soldanella (beach morning glory) and Elymus mollis (wild rye), growing along the costal areas in Tae-An, Chungnam Province, were analyzed using a culture-dependent approach. A total of 212 bacteria were isolated from the root and rhizosphere samples of the two plants, and subjected to further analysis. Based on the analysis of the 16S rDNA sequences, all the bacterial isolates were classified into six major phyla of the domain Bacteria. Significant differences were observed between the two plant species, and also between the rhizospheric and root endophytic communities. The isolates from the rhizosphere of the two plant species were assigned to 27 different established genera, and the root endophytic bacteria were assigned to 21. Members of the phylum Gammaproteobacteria, notably the Pseudomonas species, comprised the majority of both the rhizospheric and endophytic bacteria, followed by members of Bacteroidetes and Firmicutes in the rhizosphere and Alphaproteobacteria and Bacteroidetes in the root. A number of isolates were recognized as potentially novel bacterial taxa. Fifteen out of 27 bacterial genera were commonly found in the rhizosphere of both plants, which was comparable to 3 out of 21 common genera in the root, implying the host specificity for endophytic populations. This study of the diversity of culturable rhizospheric and endophytic bacteria has provided the basis for further investigation aimed at the selection of microbes for the facilitation of plant growth.

• 한국식품영양과학회지
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• 제27권2호
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• pp.244-251
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• 1998

To understand the effect of supplement of water extract of pine needle(WEPN) on shelf-life enhancement of the kimchi, activities of four enzymes and number of lactic acid bacteria, during fermentation of the kimchi, were assayed. Enzyme activities of kimchi fermented for 7 days with supplement by 2% water extract of pine needle showed amylase of 86.4%, protease of 85.8%, polygalacturonase of 61.5% and $\beta$-galactosidase of 58.8% against the control kimchi. WEPN showed weak inhibitory effect when it was applied to the isolated enzymes in vitro then those menifested by the kimchi in vivo. Number of total bacterial cell of WEPN supplemented kimchi increased by 10 folds than control between 7 to 14 days of fermentation. On contrast, number of lactic acid bacteria decreased maximaly to 21% of control by fermentation. The clear zone formed on paper disk by WEPN against L. plantarum was larger than that of Leu. mesenteroides.

• 한국어병학회지
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• 제8권2호
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• pp.149-156
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• 1995

파래투여에 따른 생리활성에 미치는 영향을 조사하기 위하여 이스라엘잉어에 대상으로 공기노출에 따른 혈액성상의 변화를 조사하였고 아울러서 비단잉어를 대상으로 A. sobriae에 대한 항균력과 항응집소가를 조사하였던 바 그 결과는 다음과 같다. 이스라엘잉어를 대상으로 4개월간 파래첨가사육후에 공기노출에 따른 혈액성상에 미치는 영향에 있어서 Ht치는 파래첨가의 유무에 관계없이 큰 차이를 보이지 않았으며, 헤모글로빈, 총단백, 알부민 및 글루코스치는 대조군에 비해 첨가군에서 증가되는 경향을 보였으며, 특히 5% 첨가군에서 높게 나타났다. 그렇지만, GPT 및 GOT치는 대조군에 비해 파래 첨가농도에 비례하여 감소하는 경향을 보였다. 한편, 비단잉어를 대상으로 파래추출물을 1주간 복강내로 투여후 A. sobriae에 대한 항균능은 대조군에 비해서 첨가군 모두에서 낮게 나타났으며, 특히 $30{\mu}g/g$ 투여군에서 $4{\times}10^4$ CFU로 최저치를 나타냈다. 한편, 항응집소가는 대조군에 비해 파래추출물 투여군 모두에서 증가되었으며, 특히 $30{\mu}g/g$ 투여군에서 $6.0{\pm}1.1$로서 최고치를 보였다.