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        검색결과 590

        41.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study evaluated the effect of lactic acid bacteria (LAB, a mixture of Enterococcus faecium and Lactobacillus plantarum) supplementation, the storage temperature, and storage period on the fermentation characteristics and in vitro ruminal digestibility of a total mixed ration (TMR). The TMR was prepared into two groups, namely, CON (control TMR without the LAB) and ML (supplementing a mixture of E. faecium and L. plantarum in the ratio of 1% and 2% (v/w), respectively). Both groups were divided and stored at 4°C or 25°C for 3, 7, and 14 d fermentation periods. Supplementing LAB to the TMR did not affect the chemical composition of TMR except for the lactate and acetate concentration. Storage temperatures affected (p<0.05) the chemical composition of the TMR, including pH, lactate, and acetate contents. The chemical composition of TMR was also affected (p<0.05) by the storage period. During in vitro rumen fermentation study, the ML treatment showed lower (p<0.05) dry matter digestibility at 24 h incubation with a higher pH compared to the CON. There was no difference in the in vitro dry matter digestibility (IVDMD) of TMR between the CON and ML treatment however, at 24 h, ML treatment showed lower (p<0.05) IVDMD with a higher pH compared to the CON. The effects of storage temperature and period on IVDMD were not apparent at 24 h incubation. In an in vivo study using Holstein steers, supplementing LAB to the basal TMR for 60 d did not differ in the final body weight and average daily gain. Likewise, the fecal microbiota did not differ between CON and ML. However, the TMR used for the present study did include a commercial yeast in CON, whereas ML did not; therefore, results were, to some extent, compromised in examining the effect of LAB. In conclusion, storage temperature and period significantly affected the TMR quality, increasing acetate and lactate concentration. However, the actual effects of LAB supplementation were equivocal.
        4,000원
        42.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To enhance the bioavailability and bioactivities of mixed herbal medicines (RW), they were fermented with lactic-acid bacteria isolated from kimchi into postbiotics (FRW). Then, from the results of the 16s rRNA sequencing analysis, lactic acid bacteria isolated from kimchi were identified to be of two species, namely Lactobacillus sakei and Leuconostoc mesenteroides. The FRW prepared from the RW were extracted using hot water (HW) and 70% EtOH (EtOH) for comparison of their macrophage-stimulating activities. Based on a comparison of the activities of the FRW extracts, nitric oxide (NO) production of HW was significantly higher than that in EtOH. An analysis of the chemical properties of the extracts showed that HW had higher contents of neutral sugar and uronic acid than EtOH as well as contained a large amount of glucose. In addition, crude polysaccharide (CP) was prepared to enhance the macrophage-stimulating activity. The FRW-CP not only secreted immunostimulatory mediators but also increased the expression of immunostimulatory genes (iNOS, TNF-α, MCP-1, and IL-6). The fractionated FRW-CP contained about 90% neutral sugars, and these sugars were mainly composed of glucose, galacturonic acid, and arabinose. Thus, FRW prepared by fermentation of RW with kimchi lactic acid bacteria were found to be immunostimulatory modulators.
        4,300원
        43.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to investigate how airborne bacteria are distributed under different temperature conditions while cultivating oyster mushrooms by setting the indoor temperature of the cultivation room to 10°C, 15°C, 20°C, 25°C, and 30°C. The surveys were conducted in April and May, respectively. Airborne bacterial concentrations were distributed in the range of 1.61 × 102 ~ 3.67 × 102 CFU/m3 in April and 5.47 × 102 ~ 7 × 103 CFU/ m3 in May. In May, the indoor air quality maintenance standard (8.0 × 102 CFU/m3) was exceeded in the 10°C, 20°C, and 25°C cultivation rooms. Bacterial concentrations increased significantly in May compared to April. Bacterial concentrations were different between the cultivation rooms at different temperatures. The difference was more pronounced in May than in April. A total of 15 genera and 20 species were isolated from the indoor air of the oyster mushroom cultivation rooms. Overall, it was most abundant in Actinomycetia. Among the species identified, Agrobacterium radiobacter, Brevundimonas vesicularis, Kocuria palustris, K. salsicia, Lysinibacillus fusiformis, and Sphingobacterium siyangense are known to affect human health. This is the first report of airborne bacteria in cultivation rooms at different temperatures used for oyster mushroom cultivation. The results of this study are expected to be used as basic data to understand the indoor environment of thermophilic mushroom cultivation facilities.
        4,000원
        44.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        음식물류폐기물 직매립, 해양투기 등이 금지됨에 따라 음식물류폐기물은 대부분 자원화를 통해 처리되며 퇴비화하여 생산한 음식물류혼합퇴비(이 하, 음폐퇴비)는 작물 생산성을 향상 등을 위하여 농경지에 퇴비로 사용한다. 하지만, 염분 집적에 의한 작물 생육이 우려되며 이에 따른 피해를 줄이기 위하여 음폐퇴비와 블랙카본, 유용 미생물을 함께 사용하면 염분에 의한 피해를 줄일 수 있을 것으로 기대된다. 이에 본 연구는 음폐퇴비와 바이오차의 한 종류인 블랙카본, 유용 미생물을 처리 시 상추의 수량과 토양 특성 변화를 알아보고자 하였다. 처리구는 무비구(NF), 무기질 비료 (NPK), 무기질 비료 + 음폐퇴비 (NPKF, 대조구), 무기질 비료 + 음폐퇴비 + 블랙 카본 (NPKFC), 무기질 비료 + 음폐퇴비 + 미생물 (NPKFB), 무기질 비료 + 음폐퇴비 + 블랙카본 + 미생물 (NPKFCB)이다. 상추 생육 조사 결과, 생육 후기인 21일째에 NPKFCB 처리구에서 엽장 20.7 cm, 엽폭 20.2 cm, SPAD-502 32.0으로 가장 생육이 좋았으며, 수량 조사 결과 또한 NPKFCB 처리구에서 주당 총 엽수가 28.8개로 가장 많았다. 수량지수는 무처리가 84.1로 가장 낮았고 NPKFCB 처리구에서 128.7로 가장 높았다. 이는 블랙카본에서 공급되는 K, P, Ca 등의 양분과 미생물 활성화가 작물 생산성 향상에 도움을 준 것으로 판단된다. 토양 화학성 분석 결과 pH는 NPKFB 처리구에서 6.9로 가장 높았으며, EC는 NPKF에서 1.7 dS m-1로 가장 높았다.
        4,000원
        45.
        2022.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate the effects of antioxidant and anti-inflammatory activities of heat-killed lactic acid bacteria (LAB) produced under different temperature conditions. Regarding probiotic properties, Limosilactobacillus fermentum SMF743 and Lactiplantibacillus plantarum SMF796 isolated from kimchi showed strong acid and bile salt resistance, adhesion activity onto HT-29 cells, and antimicrobial activity against pathogenic bacteria. Based on the results of thermal death time and temperature, heat-killed LAB cells (1 mg/mL) were prepared by heating at 70oC (180 min), 80oC (120 min), 100oC (30 min), and 121oC (15 min). The heat-killed SMF743 and SMF796 showed significantly higher DPPH and ABTS radical scavenging activities than live cells (p<0.05). The heat-killed SMF743 and SMF796 at 70oC or 121oC revealed stronger DPPH and ABTS radical scavenging activities and inhibition of nitric oxide production than those at 80oC or 100oC. Furthermore, heat-killed SMF743 and SMF796 at 121oC significantly reduced the gene expression levels of tumor necrosis factor-, inducible nitric oxide synthase, and cyclooxygenase- 2 up to 53.33%, 58.67%, and 83.67%, respectively, in lipopolysaccharide (LPS)-induced RAW264.7 cells (p<0.05). These results suggest that heat-killed L. fermentum SMF743 and L. plantarum SMF796 can be used as natural antioxidants and anti-inflammatory agents.
        4,200원
        49.
        2022.10 구독 인증기관·개인회원 무료
        Spent nuclear fuel (SNF) is the main source of high-level radioactive wastes (HLWs), which contains approximately 96% of uranium (U). For the safe disposal of the HLWs, the SNF is packed in canisters of cast iron and copper, and then is emplaced within 500 m of host rock surrounded by compacted bentonite clay buffer for at least 100,000 years. However, in case of the failure of the multi-barrier disposal system, U might be migrated through the rock fractures and groundwater, eventually, it could reach to the biosphere. Since the dissolved U interacts with indigenous bacteria under natural and engineered environments over the long storage periods of geologic disposal, it is important to understand the characteristics of U-microbe interactions under the geochemical conditions. In particular, a few of bacteria, i.e., sulfate-reducing bacteria (SRB), are able to reduce soluble U(VI) into insoluble U(IV) under anaerobic conditions by using their metabolisms, resulting in the immobilization of U. In this study, the aqueous U(VI) removal performance and change in bacterial community in response to the indigenous bacteria were investigated to understand the interactions of U-microbe under anaerobic conditions. Three different indigenous bacteria obtained from different depths of granitic groundwater (S1: 44–60 m, S2: 92–116 m, and S3: 234–244 m) were used for the reduction of U(VI)aq. After the anaerobic reaction of 24 weeks, the changes in bacterial community structure in response to the seeding indigenous bacteria were observed by high-throughput 16S rDNA gene sequencing analysis. The highest uranium removal efficiency of 57.8% was obtained in S3 sample, and followed by S2 (43.1%) and S1 (37.7%). Interestingly, SRB capable of reducing U(VI) greatly increased from 4.8% to 44.1% in S3 sample. Among the SRB identified, Thermodesulfovibrio yellowstonii played a key role on the removal of U(VI)aq. Transmission electron microscopy (TEM) analysis showed that the dspacing of precipitates observed in this study was identical with that of uraninite (UO2). This study presents the potential of U(VI)aq removal by indigenous bacteria under deep geological environment.
        51.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Lactic acid bacteria as probiotics are intensively used in human and animal species. These probiotic properties of LABs were variable according to bacterial strain and species. However, there was limited information on probiotic properties of monkey origin LABs. In this study, we investigated the antibacterial activity of monkey and human origin LABs against monkey origin enteric bacteria by the agar disc diffusion test and broth culture inhibition assay. All LABs represented enough tolerance to pepsin (0.3%) and bile acid (pH = 2). To 50% of Clostridium perfringens and 20% of Escherichia coli, monkey origin LABs showed statistically higher antibacterial activity compared to human origin LABs (p < 0.05). Also, distinct antibacterial activity was verified among some bacteria species and strains. Higher antibacterial activity against enteric bacteria except for C. perfringens was verified in Lactobacillus johnsonii strains compared to Lactobacillus reuteri and Lactobacillus salivarius. Statistically different antibacterial activity against C. perfringens was verified among strains within L. reuteri and L. johnsonii. In conclusion, we prove the higher probiotic properties of monkey origin LABs against homogenous enteric bacteria although humans and monkeys were phylogenetically similar species. For non-human primates, homogenous LABs should be used as probiotics, not human origin LABs. Furthermore, it was confirmed among monkey origin LABs, L. johnsonii showed a high antibacterial activity on various enteric pathogenic bacteria and was an appropriate lactic acid strain for inhibiting C. perfringens.
        4,200원
        52.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Distribution of airborne bacteria in the entire regions of South Korea was investigated and analyzed by region and type of multi-use facilities. At first, 10 public facilities were selected including general restaurant, retail store, public transport, retail market, apartment house, underground parking lot, financial institution, business facility, educational institution, and public toilet, which are located at the regions such as Seoul, Busan, Daejeon, Gwangju, Gyeonggi, Jeju, and Gangwon. The regional distribution of the floating bacteria was identified that Micrococcus sp. was highly prevalent in Seoul (21.5 percent). In Daejeon, Bacillus sp. was highly prevalent (12.4 percent). In Busan, Micrococcus sp. was highly prevalent (22.8 percent). In Gwangju, Bacillus sp. was 9.35%. In Gyeonggi, Micrococcus sp. was 13.7%, and in Gwangju and Jeju, Micrococcus sp. was 11.2 percent and 92%. All in all, Micrococcus sp. and Bacillus sp. were highly detected throughout the entire region and multi-use facilities. Next, whether or not these airborne bacteria could influence the health of people was examined using HaCat human skin cell line which is human epithermal Karatinocytes related to allergic dermatitis. Among these isolated microorganisms, the HaCat cell proliferation was decreased by Arthrobacter sp., Bacillus sp., Brachybacterium sp., Brevundimonas sp., Kocuria sp., Mammaliicoccus sp., Norcardia sp., Prestia sp., Phychrobacillus sp., and Rhodococcus sp., while it was affected by the other bacteria. Therefore, these results have suggested that the airborne floating bacteria could be considered as the marker for the environmental risk management against atopic dermatitis, and it is needed for controlling the bacteria number that suppressed the proliferation of HaCat cells.
        4,000원
        53.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        식중독 세균에 의한 biofilm 형성을 억제하는 효과를 시 험하기 위하여 cinnamon, clove 및 lemongrass 정유의 휘 발성 성분을 분석하였다. 또한 정유의 주요 항균활성 성 분이 polyethylene과 stainless steel 표면에서 식중독 세균 에 의한 biofilm 형성을 억제하는 효과에 대하여 조사하였 다. Cinnamon 정유의 주요 휘발성 성분은 cinnamaldehyde (38.30%), linalool (9.61%), β–caryophyllene (8.90%) 및 1,3,4-eugenol (8.19%)로 동정되었다. Clove 정유의 주요 휘발성 성분은 1,3,4-eugenol (61.84%)로 분석되었다. Lemongrass의 주요 휘발성 성분은 citral의 이성질체인 geranial (19.11%)과 neral (19.23%)로 검출되었으며, citral 은 isomeric acyclic monoterpene aldehydes로서 geranial (trans-citral, 19.11%)과 neral (cis-citral, 19.23%)의 혼합물 로 분석되었다. Cinnamon, clove 및 lemongrass의 주요 성 분 중 cinnamaldehyde, linalool, eugenol 및 citral이 disc diffusion assay에 의해 시험한 6종의 식중독 세균에 대하 여 강한 항균활성을 나타냈다. Eugenol (0.1%)과 citral은 polyethylene 및 stainless steel coupon 표면에서 식중독 세 균에 의해 형성된 biofilm에 대하여 강한 억제 작용을 나 타났다. Cinnamaldehyde (0.1%)는 Listeria monocytogenes ATCC 19112와 Staphylococcus aureus KCCM 11812에 의 해 형성된 biofilm에 대해 장한 억제 작용을 나타냈다. 연 구 결과 cinnamaldehyde, eugenol 및 citral 처리에 의해 식 중독 세균에 의한 biofilm 형성을 억제가 가능할 것으로 판단된다.
        4,200원
        54.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 병원균인 Bacillus cereus, Staphylococcus aureus, Salmonella Typhimurium 그리고 Escherichia coli O157:H7을 이산화염소수와 전해수에 0분, 2분, 4분, 6분, 8분 및 10분간 반응시켜 이산화염소수와 전해수의 살균 효과를 확인하고, 그람 양성균(B. cereus, S. aureus)과 그 람 음성균(S. Typhimurium, E. coli O157:H7)의 민감성 비 교를 실시하였다. B. cereus, S. aureus, S. Typhimurium 그 리고 E. coli O157:H7의 이산화염소수에서의 D값은 1.85±0.64, 2.06±0.85, 2.26±0.89 그리고 2.59±0.40분으로 나 타났고 전해수의 경우 각각 2.13±0.32, 1.64±0.64, 1.71±0.32 그리고 1.86±0.36분으로 나타났다. 각 용액에 처리한 10분 간 모든 균주에서 꾸준한 감소 추세를 나타내었으며 각 용액에서 각 균주의 D값은 서로 유의적인 차이는 보이지 않았다 (P>0.05). 이산화염소수와 전해수의 살균력을 비교 한 결과 D값은 유의적인 차이가 나타나지 않았으나, pH 와 유효염소농도 모두 이산화염소가 전해수보다 낮은 값 을 보였다. 살균·소독을 실시할 대상의 pH에 대한 민감성 과 같은 특성을 고려하여 최적의 살균제를 선택하고, 최 적의 농도를 결정하여 식품 산업에 적용하기 위한 자료로 활용될 것으로 기대된다.
        4,000원
        55.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 건열처리를 통해 알팔파 종자에 접종된 Bacillus cereus ATCC 12480, Listeria monocytogenes ATCC SSA81, Staphylococcus aureus ATCC 6538, Escherichia coli O157:H7 ATCC 43894, Salmonella Typhimurium ATCC 14028을 발아율에 영향 없이 불활성화 시키는 조건(65oC 에서 21일, 70oC에서 16일, 75oC에서 10일, 80oC에서 7일)을 조사하였다. 알팔파 종자를 6-7 log CFU/g 수준으로 접종 하고 65, 70, 75, 80oC로 건열처리 한 후, 발아율을 확인 하였다. 알팔파 종자의 발아율은 시장에 유통되고 있는 알 팔파 새싹의 발아율 기준인 70%로 설정하였다. 알팔파 종 자에서 B. cereus는 65oC에서 21일, 70oC에서 18일, 75oC 에서 14일, 80oC에서 4일, Listeria monocytogenes는 65oC에서 21일, 70oC에서 18일, 75oC에서 12일, 80oC에서 7일, S. aureus는 65oC에서 18일, 70oC에서 18일, 75oC에서 11 일, 80oC에서 4일, E. coli O157:H7은 65oC에서 21일, 70oC 에서 18일, 75oC에서 12일, 80oC에서 6일, Sal. Typhimurium 은 65oC에서 24일, 70oC에서 22일, 75oC에서 14일, 80oC 에서 7일 이상 건열처리 하였을 때 완전히 불활성화 되었 다. 모든 균주는 65oC에서 80oC로 온도가 상승할 때 특정 온도에서 세균의 90%를 죽이는 데 필요한 시간인 D-값 (R2=0.5656−0.7957)이 유의미하게 감소하였다(P<0.05). 80oC 에서 7일간 건열처리 하였을 때 발아율이 70% 미만으로 감소하였기 때문에 75oC에서 14일간 건열처리 하는 것이 알팔파 종자의 안전성을 확보하는데 있어 가장 효과적인 방법이다. 이 연구는 알팔파 종자의 안전성을 확보하고 일 정한 품질의 새싹을 생산하는데 기초자료로 이용될 것으 로 기대된다.
        4,000원
        56.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A field study was conducted to reduce airborne bacteria by supplying active ions to indoor spaces used by vulnerable human groups spending substantial amounts of time in places such as schools and hospitals. In an experiment conducted during school hours (8:00-15:00), the average number of airborne bacteria in classrooms was 345.53 CFU/m3 or more without active ions. However, ion supply reduced the airborne bacteria to an average of 113.23 CFU/m3, indicating an efficiency of 61.61%. As a result of tests in 33 rooms used for surgery in small and middle sized hospitals, ion supply for 2 to 4 hours reduced the average airborne bacteria concentration from 243.88 CFU/m3 to 104.34 CFU/m3, representing a 41.53% reduction. A laboratory test to confirm the ion activity has shown that the mortality rate of E. coli used as a test bacterium increased with exposure time to ions. The initial colony number of E. coli was 251 CFU, but decreased to 4 CFU after 60 minutes of exposure to active ions. Therefore, it was confirmed that the supply of active ions can contribute to the control of airborne bacteria in the indoor environment of schools, hospitals and other public facilities.
        4,000원
        57.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Natural environmental resources are considered a prospective source of microorganisms capable of producing biocatalysts with great potential in industrial areas. Arable soil fertilized with peat moss is a habitat for various microorganisms. The present research focused on the isolation and identification of hydrolase-producing bacteria that thrive at a broad temperature range. In this study, a total of 33 strains were isolated from arable soil fertilized with peat moss (Silla Garden in Busan, South Korea). The isolated bacteria were mesophiles and thermophiles with a wide temperature range. Taxonomic identification showed that the isolated strains belonged to 2 phyla, 5 families, 10 genera, and 24 species. Subsequently, the isolated strains were screened for hydrolase (amylase, lipase, and protease) activity. All isolates possessed activity of at least one enzyme and six bacterial isolates produced combined extracellular enzymes. Diversity of soil bacteria species in the present study suggest the potential of soil bacteria in the various industrial applications.
        4,000원
        58.
        2022.05 구독 인증기관·개인회원 무료
        Deep geological repository (DGR) has been considered as a globally accepted strategy to dispose high-level radioactive wastes. During long storage periods of 100,000 years, uranium (U) could be migrated through fractures in deep granite aquifers and interact with indigenous bacteria under anaerobic condition. Anaerobic bacteria can reduce U(VI) and further precipitate in the form of U(IV)-oxide minerals by transferring electrons through c-type cytochrome. In this point of view, a comprehensive understanding of uranium-microorganisms interaction is necessary to guarantee the safety of high-level radioactive waste disposal. Although diverse bacterial communities are present in DGR environment, a number of studies have been focused on some model bacteria, such as Desulfovibrio, Geobacter, and Shewanella spp.. In this study, indigenous bacterial community in deep granitic groundwater at 234–244 m was inoculated to sterile uranium-contaminated granitic groundwater amended with 20 mM of sodium acetate, and then incubated under anaerobic condition for 12 weeks. Bio-reduction of U(VI) to U(IV) by indigenous bacteria in uranium-contaminated groundwater was investigated during whole operation period. Initial U(VI) concentration of 885.4 μg·L−1 gradually decreased to 586.1 μg·L−1, resulting in approximately 33.8% of aqueous U(VI) removal efficiency. Oxidation-reduction potential (ORP) value was gradually decreased from 175.4 mV to –243.0 mV after the incubation of 12 weeks. The decrease in ORP value was attributed to the presence of aerobic bacteria and facultative anaerobic bacteria in indigenous bacterial community. The shift in bacterial community structure was observed by 16S rRNA gene high-throughput sequencing analysis. Proteobacteria (55.6%), Firmicutes (24.1%), Actinobacteria (5.5%), and Bacteroidetes (5.4%) were dominant in initial indigenous bacterial community, while Proteobacteria (94.8%) was found to be the only abundant phylum after the reaction. In addition, great increase in the relative abundance of sulfate-reducing bacteria (SRB) was observed: the relative abundance of SRB increased from 11.4% to 44.3% after the reaction. This result indicates that the SRB played a key role in the removal of aqueous U(VI). This finding shows the potential of aqueous U(VI) removal by indigenous bacteria in DGR environment.
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