• Korean Journal of Microbiology
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• v.32 no.3
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• pp.238-244
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• 1994

To investigate the bacterial potentials for utilizing dissolved organic matter in highly eutrophic estuary, the annual fluctuations of microbiological and physicochemical environmental parameters were analyzed in Naktong River Estuary. Total bacterial number ranged from 0.33 to $2.09{\times}10^7$ cells/ml, and correlated with the heterotrophic bacterial numbers in more eutrophic sites, especially. Bacterial biovolume and biomass varied between 0.064 and 0.156 2.09${\mu}m^3$/cell, 0.163 and 1.036 ${\mu}g$-C/ml, respectively. Bacterial secondary productivity ranged from 0.24 to 60.86 ${\mu}g$-C/l/h, and showed high correlations with the environmental parameters of pollution indicator. The seasonal variation pattern of bacterial productivity in freshwater sites was high in winter and low in summer, which was interpreted as the results of pollution loads varied with the amount of rainfall. In seawater site, the pattern was different from those of freshwater sites; high in summer and low in winter. In this site, the values of bacterial productivity showed positive correaltions with chlorophyll a, heterotrophic bacterial number, and temperature (r>0.5, p<0.05). These results suggested that the main source of organic matter which influences the bacterial productivity may be allochthonous materials in the upper freshwater zone of Naktong River Barrage, and autochthonous algal excretory products in the lower seawater zone of Naktong River Barrage.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.1
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• pp.117-123
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• 2022

Recently, due to COV ID-19, many people are spending most of their time indoors. So, there is a rising interest on the indoor air quality in the field of building construction. The main sources for the indoor air pollution are human indoors activity, building materials, living supplies and the polluted air from outdoor. The Korean government has designated 17 indoor air pollutants including fine dust, total airborne bacteria, fungi and carbon dioxide, etc.. Most people are always exposed to assorted bacteria and molds in our daily life, because indoor environment for human, moderate temperature are humidity, it is favourable to the growth of most of bacteria and fungi. Pine needles have an antibacterial effect against bacteria and fungi. In this study, the antibacterial activity against bacteria and fungi was tested by cement matrix using pine needle extract. As a result, the cement matrix using pine needle extract showed antibacterial activities against bacteria, but in the case of fungi, it did not show antifungal activity.

• Journal of Life Science
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• v.33 no.11
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• pp.944-949
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• 2023

The purpose of this study was to identify conserved metabolic pathways and conserved genes in 122 archaeal species. Using the Clusters of Orthologous Groups of Proteins (COG) database of conserved genes, we analyzed whether 122 species had 63 COG metabolic pathways, the 822 COGs that compose them, and a total of 4,877 COGs. Archaeal ribosomal proteins were the most conserved in metabolic pathways. 46 COGs in seven COG pathways among 63 COG pathways and 20 COGs in others were conserved in 122 species. Some genes involved in cell wall and extracellular matrix synthesis, replication, transcription, translation, and protein metabolism were common to all 122 species. When the distance value of the phylogenetic tree was analyzed at the phylum level or class level, the average was the lowest at the class Halobacteria of the phylum Euryarchaeota. Standard deviation was high for the class Nitosospharia of the phylum Thaumarchaeota, the unclassified members of phylum Thaumarchaeota, the class Halobacteria of the phylum Euryarchaeota, the class Thermoprotei of the phylum Crenarchaeota, and other archaea. Furthermore, the phylogenetic tree analysis revealed six commonalities. The results of this study, along with data on conserved genes, could be used for drug development and gene selection for strain improvement.

• Environmental Analysis Health and Toxicology
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• v.22 no.4
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• pp.313-320
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• 2007

본 연구는 인간의 건강과 식품의 오염을 예방하기 위한 유용한 자료를 얻기 위하여 육류(소고기, 닭고기, 돼지고기)로부터 분리된 staphylococci를 가지고 한국에서 광범위하게 사용되는 6가지 항생제와 daptomycin, linezolid, quinupristin/dalfopristin and tigecycline과 같은 4가지의 신항생제에 대한 항생제 감수성 시험을 수행하였다. 이에 더하여 육류의 세균 오염실태를 조사하기 위하여 총 세균수와 대장균수를 측정하였다. 그 결과 147개의 육류 샘플 중 48%의 샘플에서 일반세균수의 기준에 부적합한 결과가 나타났으며, 대장균수에 대해서는 31%의 샘플에서 기준에 부적합한 결과가 나타났다. 또한 육류의 91%에서 stapylococci가 검출되었으며 이들 staphylococci는 Coagulase Negative Staphylococci (CNS)와 S. aureus로 동정되었다. 분리된 staphylococci의 5.4%가 methicillin (oxacillin)에 내성을 나타내었고, 특히 mupirocin ($MIC_{90},\;>\;12\;{\mu}g/mL$) gentamicin ($MIC_{90},\;64\;{\mu}g/mL$)에 높은 내성을 나타내었다. 그러나 신항생제에 대해서는 methicillin 내성 staphylococci를 포함한 모든 staphylococci 분리균주가 높은 감수성을 나타내었다. 결론적으로 본 연구의 결과들은 육류가 소비자들의 건강에 중요한 위험요소로 작용할 수 있음을 보여주고 있다.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.10a
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• pp.255-258
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• 2005

닭고기의 함수율이 증가함에 따라 저장 5일의 6% 처리구에서 TBARS 값이 0.067, 8%, 0.082, 10%, 0.093 mgMA/kg으로 계속 증가하는 경향을 나타내었다. 육색에서 명도(L*), 황색도(b*)는 함수율에 따라 일정한 경향을 나타내지 않았다. 함수율에 따른 총 세균수는 저장 3일 6% 처리구에서 2.87, 8%, 2.93, 10%, 2.90 log CFU/$cm^2$로 처리 간에 큰 차이를 나타나지 않았다. 저장 5일에서 6% 처리구는 3.03, 8%, 3.01, 10%, 3.13 log CFU/$cm^2$로 10% 처리구에서 약간 증가하는 경향을 나타냈으나 함수율에 따라 큰 차이를 보이지 않았다.

• Research in Plant Disease
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• v.17 no.1
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• pp.38-43
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• 2011

Almost 10~30% of vegetables were discarded by the spoilage from farms to tables. After harvest, vegetables are often spoiled by a wide variety of microorganisms including many bacterial and fungal species. This investigation was conducted to extent the knowledge of relationship the spoilage of vegetables and the diversity of microbes. The total aerobic bacterial numbers in fresh lettuce, perilla leaf, and chicory were $2.6{\sim}2.7{\times}10^6$, $4.6{\times}10^5$, $1.2{\times}10^6\;CFU/g$ of fresh weight, respectively. The most common bacterial species were Pseudomonas spp., Alysiella spp., and Burkholderia spp., and other 18 more genera were involved in. After one week of incubation of those vegetables at $28^{\circ}C$, the microbial diversity had been changed. The total aerobic bacterial numbers increased to $1.1{\sim}4.6{\times}10^8$, $4.9{\times}10^7$, and $7.6{\times}10^8\;CFU/g$ of fresh weight for lettuce, perilla leaf, and chicory that is about $10^2$ times increased bacterial numbers than that before spoilage. However, the diversity of microbes isolated had been simplified and fewer bacterial species had been isolated. The most bacterial population (~48%) was taken up by Pseudomonas spp., and followed by Arthrobacter spp. and Bacillus spp. The spoilage activity of individual bacterial isolates had been tested using axenic lettuce plants. Among tested isolates, Pseudomonas fluorescence and Pantoea agglomerans caused severe spoilage on lettuce.

• Korean Journal of Microbiology
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• v.37 no.2
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• pp.137-144
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• 2001

In order to investigate the diversity of bacterial community in the mud flat of Sunchon Bay, Chunnam province, diversity of amplified 16S rDNA was examined. Total DNA was extracted from sediment soils and 16S rDNAs were amplified using PCR primers based on the universally conserved sequences in bacteria. Clonal libraries were constructed and 111 clones were examined by amplified rDNA restriction analysis (ARDRA) using HaeIII. Clones were clustered based on restriction patterns using computer program, GelCompar II. One hundred different RFLP types were detected from 111 clones. The 20 clones were selected and sequenced according to dendrograms derived from ARDRA, to cover most of the bacterial diversity in the clone libraries. None of the clones were identical to any representatives in the Ribosomal Database Project small subunit RNA databases and GenBank. All sequences showed between 77 and 96.8% similarity to the known 16s rRNA sequence from cultured organisms. The 20 clones sequenced fell into seven major lineages of the domain Bacteria: alpha-, delta-, gamma-Proteobacteria, low G+C Gram positive bacteria, high G+C Gram positive bacteria, Sphingobacteria (Cytophaga) and Cyanobacteria (chloroplast). Among the clones, the Proteobacteria were dominant.

• The Korean Journal of Food And Nutrition
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• v.27 no.4
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• pp.551-557
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• 2014

To improve microbiological quality of Aster scaber during storage and distribution, hurdle technology with the sanitizers and packaging methods was used. After blanching, total aerobic bacteria of Aster scaber treated with 20% ethanol and 10% NaCl were measured at 2 log CFU/g after 6 days. Total aerobic bacteria of blanched Aster scaber at $100^{\circ}C$ were measured at 2 log CFU/g, and the storage at $4^{\circ}C$ effectively inhibited the growth of bacteria. Repeated blanching using water with added NaCl at $80^{\circ}C$ showed similar microbial growth inhibition compared with treatment at $100^{\circ}C$. After vacuum packaging, blanched sample showed 2 log CFU/g of total aerobic bacteria during 10 days (the storage at $4^{\circ}C$). Therefore, repeated blanching using the water with added 10% NaCl improved the microbiological quality of Aster scaber. We also found that repeated blanching after vacuum packaging was an effective way for storage and distribution of Aster scaber. In conclusion, blanching two times in the 10% salt water or in vacuum packaging at $80{\sim}100^{\circ}C$ would be helpful to control the microbes during storage and distribution.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.54-61
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• 1999

A study was conducted to find a rapid thawing method which prevents excessive drip loss and local overheating. Effects of thawing methods (conventional thawing vs. 2,450 and 915 MHz microwave thawing) on thawing time, temperature profile, drip loss, water holding capacity, total color difference and total aerobes were investigated. Samples were thawed at 4, 28 and $50^{\circ}C$ in a refrigerator or an oven for the conventional thawing methods the convertional thawing methods. Power levels of 5, 10 and 15 kW were used for 915MHz microwave thawing. Cotreatment of 915 MHz microwave and convectional heating $(120^{\circ}C)$ was tested. 915 MHz microwave accelerated the thawing rate, and showed significant effects on penetration depth, drip loss, water holding capacity and total aerobes. Cotreatment of 915 MHz microwave and convection heating was appeared to be a suitable thawing process for the food industry.

• Korean Journal of Microbiology
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• v.53 no.4
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• pp.316-319
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• 2017

The antibiotic resistant genes (ARG) and mobile genetic elements (MGE) were investigated with the effluent of waste-water treatment plant (WWTP), and river waters of upstream and downstream in order to elucidate the effect of effluent on antibiotic resistance in a natural river. Total numbers of 134~183 of ARG and MGE were detected and the abundance of ARG and MGE was 0.063~0.422 copies per one of 16S rRNA gene in three water samples. Effluent sample contained the highest amount of the total number and abundance of ARG and MGE whereas total viable cells were observed in the lowest amount among the three samples. This indicated that the genes were originated from cells died during the wastewater treatment process. In addition, the co-relationship of abundance between ARG and MGE suggested that acquired resistance was a prevalent mechanism among the antibiotic-resistant bacteria existing in WWTP.