• Restorative Dentistry and Endodontics
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• 제48권4호
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• pp.37.1-37.17
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• 2023

This study aimed to compare the disinfectant ability of chlorhexidine (CHX) gel and sodium hypochlorite (NaOCl). Systematic searches were conducted from inception until December 8th, 2022 (MEDLINE/PubMed, Cochrane Library, Web of Science, Scopus, Embase, and Grey Literature databases). Only randomized clinical trials were included. The revised Cochrane risk of bias tools for randomized trials were used to assess the quality of studies. Meta-analyses were performed. The overall quality of evidence was assessed through the Grading of Recommendations Assessment, Development, and Evaluation tool. Six studies were included. Five had a low risk of bias and 1 had some concerns. Three studies assessed bacterial reduction. Two were included in the meta-analysis for bacterial reduction (mean difference, 75.03 [confidence interval, CI, -271.15, 421.22], p = 0.67; I² = 74%); and 3 in the meta-analysis for cultivable bacteria after chemomechanical preparation (odds ratio, 1.03 [CI, 0.20, 5.31], P = 0.98; I² = 49%). Five studies assessed endotoxin reduction. Three were included in a meta-analysis (mean difference, 20.59 [CI, -36.41, 77.59], p = 0.48; I² = 74%). There seems to be no difference in the disinfectant ability of CHX gel and NaOCl, but further research is necessary.

• 한국미생물·생명공학회지
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• 제39권2호
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• pp.133-139
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• 2011

우리나라 전남지역에서 생산되는 천일염의 생산공정별 미생물 분포 조사 및 배양 분리법을 이용하여 호염미생물을 분리하여 동정하는 것을 이번 연구의 목표로 삼았다. 천일염 시료는 생산지를 고려하여 육지 염전인 영광군 한 지역과 해안 염전 지역인 신안군 두 군데에서 생산공정별로 세분화하여 총 28개 분석시료를 수집하여 사용하였으며, 이들 시료를 십진 희석하여 4종류의 미생물 분리용 배지에 도말, 배양한 후 나타난 집락(colony)을 계수하였다. 그 결과 천일염 생산 공정 중 대장균 등의 식품 오염지표 미생물은 검출되지 않았지만, 저장수에서 증발지 단계로 진행되면서 $1.1{\times}10^3{\sim}1.8{\times}10^5$ CFU/g의 호염성 미생물들이 검출되었다. 그러나 이후 단계인 함수저장고, 결정지에서는 미생물 수가 점차적으로 감소되었으며, 소금저장소에 보관된 천일염 시료에서는 미생물이 전혀 검출되지 않았다. 이들 분리균들은 형태학적 특성에 따라 무작위로 62개 집락을 선정하여 분리하였다. 순수 분리된 미생물들은 PCR 기법을 통해 16S rRNA 유전자의 염기서열을 분석한 후, 기존에 보고된 미생물 유전자 database와 비교함으로써 12속의 천일염 유래 호염균들의 존재를 확인하였다. 이번 연구 결과 천일염 생산 단계에서 분리된 halophilic bacteria은 Halobacillus, Halomonas, Bacillus, Idiomarina, Marinobacter, Pseudoalteromonas, Vibrio, Salinivibrio, Virgibacillus, Alteromonas, Staphylococcus 및 un-known 등이다.

• 한국미생물·생명공학회지
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• 제44권3호
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• pp.293-302
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• 2016

6종류의 배지를 이용한 135일 동안 8번의 박테리아상 분석을 통하여 새우젓갈 숙성 관련 우점종을 결정하였다. Marine agar를 배양에 사용하였을 경우, 가장 많은 수의 박테리아가 검출되었고, 숙성 65일차에 그 수가 2.51 × 10⁷ CFU/g에 달하였다. 순수분 리된 총 467균주는 42속 87종으로 동정되었고, 16균주는 기존의 알려진 박테리아와 상동성을 나타내지 않았다. 1일차 분석에서 39종이 검출되었던 박테리아는 135일차에 13종으로 감소하여 우점화가 진행됨을 학인하였다. 속 수준에서의 우점은 Staphylococcus, Salimicrobium, Kocuria, Psychrobacter 순으로 나타났고, 1일차 분리균주의 2% 수준을 차지하던 Staphylococcus, Salimicrobium 속 균주는 135일차에 각각 39%와 36%에 달하였다. 우점종으로 확인된 Staphylococcus equorum, Salimicrobium salexigens, Kocuria palustris는 각각 전체 분리균주의 23.6%, 16.1%, 10.9%을 차지하였다. St. equorum와 Sm. salexigens는 21% (w/v) NaCl 농도에서의 생육이 확인되어 새우젓갈 숙성에 중요한 역할을 할 것으로 추정된다.

• Journal of Microbiology and Biotechnology
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• 제21권8호
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• pp.777-790
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• 2011

To elucidate the biodiversity of plant growth-promoting rhizobacteria (PGPR) in Korea, 7,638 bacteria isolated from the rhizosphere of plant species growing in many different regions were screened. A large number of PGPR were identified by testing the ability of each isolate to promote the growth of cucumber seedlings. After redundant rhizobacteria were removed via amplified rDNA restriction analysis, 90 strains were finally selected as PGPR. On the basis of 16S ribosomal RNA sequences, 68 Gram-positive (76%) and 22 Gram-negative (24%) isolates were assigned to 21 genera and 47 species. Of these genera, Bacillus (32 species) made up the largest complement, followed by Paenibacillus (19) and Pseudomonas (11). Phylogenetic analysis showed that most of the Grampositive PGPR fell into two categories: low- and high- G+C (Actinobacteria) strains. The Gram-negative PGPR were distributed in three categories: ${\alpha}$-proteobacteria, ${\beta}$- proteobacteria, and ${\gamma}$-proteobacteria. To our knowledge, this is the largest screening study designed to isolate diverse PGPR. The enlarged understanding of PGPR genetic diversity provided herein will expand the knowledge base regarding beneficial plant-microbe interactions. The outcome of this research may have a practical effect on crop production methodologies.

• 한국미생물·생명공학회지
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• 제47권1호
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• pp.125-131
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• 2019

We have isolated and identified 72 bacterial strains from four bentonite samples collected at the mining areas located in Gyeongsangbuk-do, Republic of Korea, and measured their hydrolytic enzyme (${\alpha}$-amylase, protease, and cellulase) activities to identify the isolates with industrial-use potential. Most of the isolates belonged to the Bacillaceae, with minor portions being from the Paenibacillaceae, Micrococcaceae, and Bacillales Family XII at the family level. Of the strains isolated, 33 had extracellular ${\alpha}$-amylase activity, 30 strains produced cellulase, and 35 strains produced protease. Strain MBLB1268, having the highest ${\alpha}$-amylase activity, was identified as Bacillus siamensis ($0.38{\pm}0.06U/ml$). Bacillus tequilensis MBLB1223, isolated from Byi33-b, showed the highest cellulase activity ($0.26{\pm} 0.04U/ml$), whereas Bacillus wiedmannii MBLB1197, isolated from Zdb130-b, exhibited the highest protease activity ($54.99{\pm}0.78U/ml$). These findings show that diverse bacteria of the Bacillaceae family adhere to and exist in bentonite and are potential sources of industrially useful hydrolytic enzymes.

• 한국초지조사료학회지
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• 제42권4호
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• pp.270-275
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• 2022

Livestock production costs are heavily influenced by the cost of feed, The use of domestically grown forages is more desirable for livestock feed production. As part of this study, triticale, which is an extremely palatable and easily cultivable crop in Korea, was used to produce low moisture silage bales with lactic acid bacteria (LAB) and then stored for different periods. We examined the nutrient content of silage, such as crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF), as well as their organic acids, including lactic acid, acetic acid, butyric acid, at different storage periods. The nutrient content of silages, such as crude protein, ADF, and NDF, did not change significantly throughout storage periods. Organic acid data indicated that lactic acid concentrations increased with increasing moisture contents and storage periods up to nine months. However, further extending storage to 12 months resulted in a reduction in the lactic acid content of all silages as well as an increase in their pH. Based on the present results, it suggested that the production of low moisture silage with the LAB may be able to preserve and maintain its quality without altering its nutritional composition. Also, the lactate content of the silage remained significant for at least nine months.

• 미생물학회지
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• 제51권1호
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• pp.86-95
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• 2015

독도의 해안에 군락을 이룬 해안식물 근권에서 호염성 및 염내성을 가지는 세균의 분리를 위해 3종의 해안식물의 군락을 선정한 후 각 식물의 군집 하부에서 토양시료를 채취하였다. 시료는 marine broth 한천배지를 이용하여 형태학적인 구분을 통해 순수분리 되었다. 분리된 161개 세균들을 NaCl 9.0% 농도로 조정된 배지에서 생존하는 26개 균주를 선발하여 genomic DNA를 얻은 후, 16S rRNA gene sequence를 증폭하여 부분동정 하였다. 이들의 유연관계 확인을 위해 계통수를 작성한 결과, 이들은 각각 Firmicutes (30.8%), Gamma proteobacteria (53.8%), Bacteroidetes (7.7%), Alpha proteobacteria (7.7%), Actinobacteria (7.7%)에 속하였으며, 이는 기존의 독도 토양 및 해수 미생물상 연구와 특징적 차이를 보인다. 또한, 분리된 세균의 종 조성도 기존 독도 토양 및 해양연구와 유의적으로 상이함을 보였다. 이에 더하여 선발된 26개 균주들 중에서 4균주가 12.0% 이상의 염농도에서 생장하였으며, 이들 중에서 3개 균주가 15.0% 이상의 염농도에서 생장하여 극호염성의 특성을 나타내었으며, 광범위한 염분농도에서도 생장하는 특성을 보였다. 이들은 해안식물 근권에서 독도 특유의 고염분 및 염분변화라는 환경적 스트레스를 극복하며 해안식물과 어떠한 상호작용을 하는 것으로 생각된다.

• Journal of Periodontal and Implant Science
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• 제23권1호
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• pp.109-126
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• 1993

Refractory periodontitis manifest progressive attachment loss in a rapid and unrelenting manner regardless of the type or frequency of therapy applied. The purpose of this study was ta evaluate the relation between the level of cytokines in GCF and periodontopathic microflora with disease activity of refractory periodontitis. Selection of patients with refractory periodontitis (7 males, 3 females) were made by long term clinical observation including conventional clinical history and parameters. Teeth that showed pocket depth greater than 6mm were selected as sample teeth. Subjects were examined at baseline and after 3 months. Prior to baseline test, individual acrylic stent was fabricated. Reference grooves were made on each sample tooth site. Pocket depth and attachment loss were measured by Florida Probe. Gingival index was measured at 4 sites each sample teeth. Disease activity was defined as attachment loss of ${\ge}$ 2.1mm, as determined by sequential probing and tolerance method. The pattern and amount of alveolar bone resorption was observed with quantitative digital subtraction image processing radiography. Morphological analysis of subgingival bacteria was taken by phase contrast microscopy. Predominant cultivable bacterial distribution and frequency were compared between disease-active and disease-inactive site using immunofluorescence microscopy and selective microbial culturing. Levels of $interleukin-l{\beta}$, 2, 4, 6 and $TNF-{\alpha}$ in GCF and blood serum sample were quantified by ELISA. In active sites, P. intermedia was significantly increased to compare with inactive site. $IL-1{\beta}$, IL-2, IL-6 and $TNF-{\alpha}$ in GCF were increased in active sites and IL-2 in serum was increased in active patients significantly. Alveolar bone loss in active site was correlated with $IL-1{\beta}$, IL-2 in GCF. And loss of attachment in active site was correlated with IL-2 in GCF. These results demonstrate that IL-2 in serum, $IL-1{\beta}$, IL-2, IL-6 and $TNF-{\alpha}$ in GCF, P, intermedia might be used as possible predictors of disease activity in refractory periodontitis before it is clinically expressed as attachment loss and quantitative alveolar bone change.