• 한국환경농학회지
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• 제38권2호
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• pp.76-82
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• 2019

저투입생산환경에서 콩 재배가 토양미생물군집활성도에 미치는 영향에 대한 결과는 다음과 같다. 초기 비료 및 퇴비 투입 후 유기물은 재배기간 내내 콩을 재배한 화분이 감자를 재배한 화분보다 높게 나타났으며, 토양 중 인산은 콩을 재배한 토양에 비해 감자를 재배한 토양에서 다소 높은 경향을 보였다. DHA 값은 콩을 재배한 토양이 생육기간 전반에 걸쳐 감자를 재배한 토양보다 유의하게 높게 나타나 토양미생물 활성도가 콩을 재배한 토양에서 증가됨을 알 수 있었고, 이러한 결과는 콩을 재배한 토양의 유기물함량 증가에도 영향을 미친것으로 판단된다. DGGE로 토양미생물군집을 분석한 결과 Proteobacteria 문(phylum)에 속하는 미생물들이 공통적으로 확인되었으며, 감자를 재배한 토양이 콩을 재배한 토양보다 다양한 미생물이 동정되었다. 또한, 콩 재배 토양의 높은 토양미생물활성도는 콩 재배 시 형성되는 소수의 특정한 미생물들에 의한 영향으로 판단된다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권8호
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• pp.1144-1151
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• 2013

In this study, protein domains with cellulase activity in goat rumen microbes were investigated using metagenomic and bioinformatic analyses. After the complete genome of goat rumen microbes was obtained using a shotgun sequencing method, 217,892,109 pair reads were filtered, including only those with 70% identity, 100-bp matches, and thresholds below $E^{-10}$ using METAIDBA. These filtered contigs were assembled and annotated using blastN against the NCBI nucleotide database. As a result, a microbial community structure with 1431 species was analyzed, among which Prevotella ruminicola 23 bacteria and Butyrivibrio proteoclasticus B316 were the dominant groups. In parallel, 201 sequences related with cellulase activities (EC.3.2.1.4) were obtained through blast searches using the enzyme.dat file provided by the NCBI database. After translating the nucleotide sequence into a protein sequence using Interproscan, 28 protein domains with cellulase activity were identified using the HMMER package with threshold E values below $10^{-5}$. Cellulase activity protein domain profiling showed that the major protein domains such as lipase GDSL, cellulase, and Glyco hydro 10 were present in bacterial species with strong cellulase activities. Furthermore, correlation plots clearly displayed the strong positive correlation between some protein domain groups, which was indicative of microbial adaption in the goat rumen based on feeding habits. This is the first metagenomic analysis of cellulase activity protein domains using bioinformatics from the goat rumen.

• Asian-Australasian Journal of Animal Sciences
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• 제33권6호
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• pp.1042-1055
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• 2020

Objective: The ecosystem of an animal farm is composed of various elements, such as animals, farmers, plants, feed, soil, and microorganisms. A domesticated animal's health is largely connected with the reservoir of bacteria and viruses in animal farms. Although a few studies have focused on exploring the gut microbiome of animals, communities of microbiota and viruses in feedlots have not been thoroughly investigated. Methods: Here, we collected feces and dust samples (4 groups: cattle feces, C_F; horse feces, H_F; cattle dust, C_D; and horse dust, H_D) from cattle and horse farms sharing the same housing and investigated their microbiome/virome communities by Illumina sequencing. Results: Dust groups (C_D and H_D) showed higher microbial diversity than feces groups (C_F and H_F) regardless of animal species. From the microbial community analysis, all the samples from the four groups have major phyla such as Proteobacteria (min 37.1% to max 42.8%), Firmicutes (19.1% to 24.9%), Bacteroidetes (10.6% to 22.1%), and Actinobacteria (6.1% to 20.5%). The abundance of Streptococcus, which commonly recognized as equine pathogens, was significantly higher in the horse group (H_D and H_F). Over 99% among the classified virome reads were classified as Caudovirales, a group of tailed bacteriophages, in all four groups. Foot-and-mouth disease virus and equine adenovirus, which cause deadly diseases in cattle and horse, respectively, were not detected. Conclusion: Our results will provide baseline information to understand different gut and environmental microbial ecology between two livestock species.

• Journal of Microbiology and Biotechnology
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• 제28권1호
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• pp.105-108
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• 2018

Beef was dry aged for 40-60 days under controlled environmental conditions in a refrigerated room with a relative humidity of 75%-80% and air-flow. To date, there is little information on the microbial diversity and characteristics of dry aged beef. In this study, we explored the effect of change in meat microorganisms on dry aged beef. Initially, the total bacteria and LAB were significantly increased for 50 days during all dry aging periods. There was an absence of representative foodborne pathogens as well as coliforms. Interestingly, fungi including yeast and mold that possess specific features were observed during the dry aging period. The 5.8S rRNA sequencing results showed that potentially harmful yeasts/molds (Candida sp., Cladosporium sp., Rhodotorula sp.) were present at the initial point of dry aging and they disappeared with increasing dry aging time. Interestingly, Penicillium camemberti and Debaryomyces hansenii used for cheese manufacturing were observed with an increase in the dry aging period. Taken together, our results showed that the change in microorganisms exerts an influence on the quality and safety of dry aged beef, and our study identified that fungi may play an important role in the palatability and flavor development of dry aged beef.

• 디지털융복합연구
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• 제14권10호
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• pp.349-354
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• 2016

다양한 extended-spectrum ${\beta}$-lactamase (ESBL)를 생성하는 폐렴막대균의 출현 및 확산은 세균에 의한 감염증 치료에 어려움을 가중시키고 있다. 본 연구에서는 충청지역에서 분리된 폐렴막대균을 대상으로 ESBL 유전자를 검출하고 항균제 감수성 양상을 조사하였다. 또한 같은 클론에서 유래하였는지를 확인하기 위해 repetitive element sequence-based (REP)-PCR을 수행하였다. 충청지역에서 분리된 폐렴막대균 102균주 중 21균주가 CTX-M-14 및/또는 CTX-M-15를 생성하는 것으로 나타났으며 이 균주들은 3세대 cephalosporin 계열 항균제에 대해 70% 이상의 높은 내성율을 보였다. 본 연구에서 분리된 CTX-M형 ESBL생성 폐렴막대균은 다양한 클론으로부터 유래되었으며 그 중 일부는 지역사회에 확산되어 있음이 확인되었다. 이러한 폐렴막대균의 감염 및 확산을 방지하기 위해서는 감염관리의 강화가 필요하다. 아울러 좀 더 효과적인 내성세균의 관리를 위해서는 내성유전자의 생물학적 조사와 통계학적 분석을 통해 통합적으로 구축된 데이터베이스를 모니터링 할 필요가 있을 것으로 사료된다.

• ALGAE
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• 제29권4호
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• pp.249-265
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• 2014

As with land crops, cultivated algae are affected by various diseases ranging from large outbreaks of a disease to chronic epiphytes, which may downgrade the value of the final product. The recent development of intensive and dense mariculture practices has enabled some new diseases to spread much faster than before. A new disease is reported almost every year, and the impact of diseases is expected to increase with environmental change, such as global warming. We observed the incidence of diseases in two Pyropia sea farms in Korea from 2011 to 2014, and estimated the economic loss caused by each disease. Serious damage is caused by the oomycete pathogens, Pythium porphyrae and Olpidiopsis spp., which decreased the productivity of the Pyropia sea farms. In Seocheon sea farms, an outbreak of Olpidiopsis spp. disease resulted in approximately US $1.6 million in loss, representing approximately 24.5% of total sales during the 2012-2013 season. The damage caused by green-spot disease was almost as serious as oomycete diseases. An outbreak of green-spot disease in the Seocheon sea farms resulted in approximately US $1.1 million in loss, representing 10.7% of total sales in the 2013-2014 season in this area. However, the causative agent of green-spot disease is still not confirmed. "Diatom felt" is regarded as a minor nuisance that does not cause serious damage in Pyropia; however, our case study showed that the economic loss caused by "diatom felt" might be as serious as that of oomycete diseases. Bacteria and cyanobacteria are indigenous members of epiphytic microbial community on Pyropia blades, but can become opportunistic pathogens under suitable environmental conditions, especially when Pyropia suffers from other diseases. A regular acid wash of the Pyropia cultivation nets is the most common treatment for all of the above mentioned diseases, and represents approximately 30% of the total cost in Pyropia sea farming. However, the acid wash is ineffective for some diseases, especially for Olpidiopsis and bacterial diseases.

• 미생물학회지
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• 제46권1호
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• pp.33-37
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• 2010

근권토양에서 분리한 세균 Bacillus subtilis RFO41은 인산 가용화능이 높고 auxin 등의 식물호르몬을 생산한다. 이 균주를 이용하여 가시도꼬마리(Xanthium italicum Moore)의 생장 촉진 실험을 화천군 파로호의 호안나대지에서 수행하였다. 19주 경과 후 자라난 가시도꼬마리를 채취하여 줄기와 뿌리 길이를 측정하고 식물을 건조시켜 중량을 측정하였다. 균주를 처리한 접종군이 미접종 대조군보다 가시도꼬마리의 건조중량이 67.7%나 높았으며 또한 가시도꼬마리의 줄기 길이도 균주를 처리한 접종군이 미접종 대조군보다 21.1% 길었는데 모두 통계적 유의성을 가졌다. 접종균주의 동태를 denaturing gradient gel electrophoresis 방법으로 조사하였는데 나대지 토양에서 접종균주가 유지되고 있으며 토양의 고유 세균군집에는 큰 영향을 미치지 않는 것을 확인하였다. 따라서 척박한 호안나대지 토양에서 B. subtilis RFO41의 인산가용화능과 식물호르몬의 생성능 등의 식물생장촉진 효과가 가시도꼬마리의 생장에 직접적인 영향을 미치는 것으로 판단할 수 있다. 이러한 식물 생장 촉진효과는 친환경적 미생물비료, 특히 민감한 호안나대지 등의 미생물학적 식생복원방법으로서의 가치를 뒷받침하는 것이라 할 수 있다.

• Journal of Ecology and Environment
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• 제40권1호
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• pp.75-83
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• 2016

Background: In order to evaluate the effect of pH, known as a critical factor for shaping the biogeographical microbial patterns in the studies by others, on the bacterial diversity, we selected two sites in a similar geographical location (site 1; north latitude 35.3, longitude 127.8, site 2; north latitude 35.2, longitude 129.2) and compared their soil bacterial diversity between them. The mountain soil at site 1 (Jiri National Park) represented naturally acidic but almost pollution free (pH 5.2) and that at site 2 was neutral but exposed to the pollutants due to the suburban location of a big city (pH 7.7). Methods: Metagenomic DNAs from soil bacteria were extracted and amplified by PCR with 27F/518R primers and pyrosequenced using Roche 454 GS FLX Titanium. Results: Bacterial phyla retrieved from the soil at site 1 were more diverse than those at site 2, and their bacterial compositions were quite different: Almost half of the phyla at site 1 were Proteobacteria (49 %), and the remaining phyla were attributed to 10 other phyla. By contrast, in the soil at site 2, four main phyla (Actinobacteria, Bacteroidetes, Proteobacteria, and Cyanobacteria) composed 94 %; the remainder was attributed to two other phyla. Furthermore, when bacterial composition was examined on the order level, only two Burkholderiales and Rhizobiales were found at both sites. So depending on pH, the bacterial community in soil at site 1 differed from that at site 2, and although the acidic soil of site 1 represented a non-optimal pH for bacterial growth, the bacterial diversity, evenness, and richness at this site were higher than those found in the neutral pH soil at site 2. Conclusions: These results and the indices regarding diversity, richness, and evenness examined in this study indicate that pH alone might not play a main role for bacterial diversity in soil.

• Childhood Kidney Diseases
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• 제21권2호
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• pp.121-127
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• 2017

Purpose: The aim of this study was to determine the prevalence of antibiotic susceptibility and resistance of Escherichia coli in urinary tract infections (UTIs) in children. Methods: We retrospectively reviewed the clinical records of 212 inpatients aged 18 years or younger with UTIs treated at the Pediatric Department of Dongguk University Gyeongju Hospital between January 2008 and December 2016. For comparison, patients were divided into three groups according to age as follows: group 1, ${\leq}1$ month; group 2, >1 month to ${\leq}12$ months; and group 3, ${\geq}13$ months. The antibiotic resistance rates from January 2008 to December 2012 (study period 1) and from January 2013 to December 2016 (study period 2) were analyzed statistically by group. Results: As the patient age increased, the antibiotic resistance rate to ampicillin (P=0.013), levofloxacin (P=0.050), piperacillin/tazobactam (TZP) (P<0.001), and trimethoprim/sulfamethoxazole (P=0.002) increased. The frequency of extended spectrum beta-lactamase producing E. coli showed a significant difference from 5 cases (4.6%) in study period 1 and 16 cases (15.8%) in study period 2 (P=0.007). The antibiotic resistance rate of E. coli was compared between the two time periods and we found that the antibiotic resistance rate to cefotaxime was significantly increased from 5.4% to 16.8% (P=0.008) and that to TZP was significantly decreased from 40.5% to 7.9% (P<0.001). Conclusion: Over the past 9 years, the resistance rate to cefotaxime has increased but the resistance rate to TZP has decreased. Thus, it is important to continue to investigate the antibiotic resistance rates of bacteria in the community.

• Journal of Microbiology and Biotechnology
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• 제21권4호
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• pp.391-399
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• 2011

Free fatty acids (FFAs) are known to have bacteriocidal activity and are important components of the innate immune system. Many FFAs are naturally present in human and animal skin, breast milk, and in the bloodstream. Here, the therapeutic potential of FFAs against methicillin-resistant Staphylococcus aureus (MRSA) is demonstrated in cultures and in mice. Among a series of FFAs, only oleic acid (OA) (C18:1, cis-9) can effectively eliminate Staphylococcus aureus (S. aureus) through cell wall disruption. Lauric acid (LA, C12:0) and palmitic acid (PA, C16:0) do not have this ability. OA can inhibit growth of a number of Gram-positive bacteria, including hospital and community-associated MRSA at a dose that did not show any toxicity to human sebocytes. The bacteriocidal activities of FFAs were also demonstrated in vivo through injection of OA into mouse skin lesions previously infected with a strain of MRSA. In conclusion, our results suggest a promising therapeutic approach against MRSA through boosting the bacteriocidal activities of native FFAs, which may have been co-evolved during the interactions between microbes and their hosts.