• Korean Journal of Clinical Laboratory Science
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• v.54 no.4
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• pp.265-272
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• 2022

The emergence and dissemination of carbapenemase-producing Enterobacteriaceae (CPE), particularly the Klebsiella pneumoniae carbapenemase-2 (KPC-2) producing Klebsiella pneumoniae, has been rapidly increasing worldwide and is becoming a serious public health threat. Since the epidemiology and characteristics of these KPC-2-producing K. pneumoniae vary according to the region and period under consideration, this study investigated the prevalence of carbapenemases and the epidemiological relationship of 78 carbapenem-resistant K. pneumoniae (CRKP) isolated from a tertiary hospital in Daejeon, from March 2017 to December 2020. The antimicrobial susceptibility tests were identified using the disk-diffusion method. PCR and DNA sequencing were used to determine the carbapenemase genes. In addition, molecular epidemiology was performed by multilocus sequence typing (MLST). Among the 78 CRKP isolates, 35 isolates (44.9%) were carbapenemase-producing K. pneumoniae (CPKP) and the major carbapenemase type was KPC-2 (30 isolates, 85.7%). The New Delhi metallo-enzyme-1 (NDM-1) and NDM-5 were identified in 4 isolates (11.4%) and 1 isolate (2.9%), respectively. Multilocus sequence typing (MLST) analysis showed 10 sequence types (STs) and the most prevalent ST was ST307 (51.4%, 18/35). All the ST307 isolates were KPC-2-producing K. pneumoniae and were multidrug-resistant (MDR). In addition, ST307 has gradually emerged during a four-year period. These findings indicate that continuous monitoring and proper infection control are needed to prevent the spread of KPC-2-producing K. pneumoniae ST307.

• Nutrition Research and Practice
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• v.17 no.4
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• pp.682-697
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• 2023

BACKGROUND/OBJECTIVES: Tibetan tea is a kind of dark tea, due to the inherent complexity of natural products, the chemical composition and beneficial effects of Tibetan tea are not fully understood. The objective of this study was to unravel the composition of Tibetan tea using knowledge-guided multilayer network (KGMN) techniques and explore its potential antioxidant and hypolipidemic mechanisms in mice. MATERIALS/METHODS: The C57BL/6J mice were continuously gavaged with Tibetan tea extract (T group), green tea extract (G group) and ddH2O (H group) for 15 days. The activity of total antioxidant capacity (T-AOC) and superoxide dismutase (SOD) in mice was detected. Transcriptome sequencing technology was used to investigate the molecular mechanisms underlying the antioxidant and lipid-lowering effects of Tibetan tea in mice. Furthermore, the expression levels of liver antioxidant and lipid metabolism related genes in various groups were detected by the real-time quantitative polymerase chain reaction (qPCR) method. RESULTS: The results showed that a total of 42 flavonoids are provisionally annotated in Tibetan tea using KGMN strategies. Tibetan tea significantly reduced body weight gain and increased T-AOC and SOD activities in mice compared with the H group. Based on the results of transcriptome and qPCR, it was confirmed that Tibetan tea could play a key role in antioxidant and lipid lowering by regulating oxidative stress and lipid metabolism related pathways such as insulin resistance, P53 signaling pathway, insulin signaling pathway, fatty acid elongation and fatty acid metabolism. CONCLUSIONS: This study was the first to use computational tools to deeply explore the composition of Tibetan tea and revealed its potential antioxidant and hypolipidemic mechanisms, and it provides new insights into the composition and bioactivity of Tibetan tea.

• Journal of Plant Biotechnology
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• v.50
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• pp.34-44
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• 2023

The tetraploid Solanum hjertingii, a wild tuber-bearing species from Mexico is a relative of potato, S. tuberosum. The species has been identified as a potential source of resistance to blackening for potato breeding. It does not exhibit enzymatic browning nor blackspot which are physiological disorders. However, due to their sexual incompatibility, somatic hybridization between S. hjertingii and S. tuberosum must be used to introduce various traits from this wild species into potato. After somatic hybridization, molecular markers are essential for selecting fusion products. In this study, the chloroplast genome of S. hjertingii was sequenced by next-generation sequencing technology and compared with those of other Solanum species to develop specific markers for S. hjertingii. The chloroplast genome has a total sequence length of 155,545 bp, and its size, gene content, order and orientation are similar to those of the other Solanum species. Phylogenic analysis including 15 other Solanaceae species grouped S. hjertingii with S. demissum, S. hougasii, and S. stoloniferum. After detailed comparisons of the chloroplast genome sequence with eight other Solanum species, we identified one InDel and seven SNPs specific to S. hjertingii. Based on these, five PCR-based markers were developed for discriminating S. hjertingii from other Solanum species. The results obtained in this study will aid in exploring the evolutionary aspects of Solanum species and accelerating breeding using S. hjertingii.

• Journal of Plant Biotechnology
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• v.50
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• pp.45-55
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• 2023

The diploid Solanum cardiophyllum, a wild tuberbearing species from Mexico is one of the relatives to potato, S. tuberosum. It has been identified as a source of resistance to crucial pathogens and insects such as Phytophthora infestans, Potato virus Y, Colorado potato beetle, etc. and is widely used for potato breeding. However, the sexual hybridization between S. cardiophyllum and S. tuberosum is limited due to their incompatibility. Therefore, somatic hybridization can introduce beneficial traits from this wild species into the potato. After somatic hybridization, selecting fusion products using molecular markers is essential. In the current study, the chloroplast genome of S. cardiophyllum was sequenced by next-generation sequencing technology and compared with those of other Solanum species to develop S. cardiophyllum-specific markers. The total length of the S. cardiophyllum chloroplast genome was 155,570 bp and its size, gene content, order and orientation were similar to those of the other Solanum species. Phylogenic analysis with 32 other Solanaceae species revealed that S. cardiophyllum was expectedly grouped with other Solanum species and most closely located with S. bulbocastanum. Through detailed comparisons of the chloroplast genome sequences of eight Solanum species, we identified 13 SNPs specific to S. cardiophyllum. Further, four SNP-specific PCR markers were developed for discriminating S. cardiophyllum from other Solanum species. The results obtained in this study would help to explore the evolutionary aspects of Solanum species and accelerate breeding using S. cardiophyllum.

• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.517-525
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• 2023

The emergence and spread of multidrug-resistant Pseudomonas aeruginosa (MRPA) have become a serious problem worldwide. The involvement of metallo-β-lactamases (MBLs) in inducing carbapenem resistance is particularly acute. However, unlike other members of the Enterobacteriaceae genus, new clones of P. aeruginosa are constantly emerging and rapidly replacing previously prevalent dominant clones. Therefore, this study aimed to perform antimicrobial resistance gene analysis, integron gene cassette analysis using DNA sequencing, and plasmid transfer analysis by conjugation to investigate the antimicrobial resistance dynamics of 18 P. aeruginosa strains isolated from various medical samples at a general hospital in Busan from September 2017 to September 2019. All 18 strains showed extensively drug-resistant (XDR) phenotype and were resistant to most antibiotics, except colistin (100%) but were susceptible to aztreonam (22.2%) and ceftazidime (16.6%). Approximately 66.7% of the strains had Class 1 integrons showing various antimicrobial resistances. Notably, IMP-6 ST235 (66.7%), VIM-2 ST357 (16.7%), and IMP-1 ST446(16.7%) were identified. The identification of IMP-1-producing ST446, previously unreported in Korea, is noteworthy considering the emergence and prevalence of another MRPA high-risk clone.

• Animal Bioscience
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• v.37 no.7
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• pp.1168-1176
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• 2024

Objective: As a charismatic species, cashmere goats have rich genetic resources. In the Inner Mongolia Autonomous Region, there are three cashmere goat varieties named and approved by the state. These goats are renowned for their high cashmere production and superior cashmere quality. Therefore, it is vitally important to protect their genetic resources as they will serve as breeding material for developing new varieties in the future. Methods: Three breeds including Inner Mongolia cashmere goats (IMCG), Hanshan White cashmere goats (HS), and Ujimqin white cashmere goats (WZMQ) were studied. IMCG were of three types: Aerbas (AEBS), Erlangshan (ELS), and Alashan (ALS). Nine DNA samples were collected for each population, and they were genomically re-sequenced to obtain high-depth data. The genetic diversity parameters of each population were estimated to determine selection intensity. Principal component analysis, phylogenetic tree construction and genetic differentiation parameter estimation were performed to determine genetic relationships among populations. Results: Samples from the 45 individuals from the five goat populations were sequenced, and 30,601,671 raw single nucleotide polymorphisms (SNPs) obtained. Then, variant calling was conducted using the reference genome, and 17,214,526 SNPs were retained after quality control. Individual sequencing depth of individuals ranged from 21.13× to 46.18×, with an average of 28.5×. In the AEBS, locus polymorphism (79.28) and expected heterozygosity (0.2554) proportions were the lowest, and the homologous consistency ratio (0.1021) and average inbreeding coefficient (0.1348) were the highest, indicating that this population had strong selection intensity. Conversely, ALS and WZMQ selection intensity was relatively low. Genetic distance between HS and the other four populations was relatively high, and genetic exchange existed among the other four populations. Conclusion: The Inner Mongolia cashmere goat (AEBS type) population has a relatively high selection intensity and a low genetic diversity. The IMCG (ALS type) and WZMQ populations had relatively low selection intensity and high genetic diversity. The genetic distance between HS and the other four populations was relatively high, with a moderate degree of differentiation. Overall, these genetic variations provide a solid foundation for resource identification of Inner Mongolia Autonomous Region cashmere goats in the future.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.5
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• pp.690-700
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• 2012

The experiment was conducted by in vitro fermentation and bacterial community analysis to investigate the reduction of odorous compounds in response to the use of feed additives (FA) during carbohydrate overload in growing pigs. Soluble starch at 1% (control) and various FA at 0.1% Ginseng meal (FA1); Persimmon leaf (FA2); Gingko nut (FA3) and Oregano lippia (FA4) were added to fecal slurry and incubated anaerobically for 12 and 24 h. In vitro parameters and microbial diversity of the dominant bacteria following fermentation were analyzed using Denaturing Gradient Gel Electrophoresis (DGGE), band cloning and sequencing of the V3 region. Results showed that total gas production increased with the advancement of incubation (p<0.05). pH values of FAs and control groups were decreased except the FA4 group which increased somewhat from 12 to 24 h (p<0.05). Ammonia nitrogen ($NH_3$-N) and $H_2S$ gas concentrations were comparatively lower in both stages in FA4 treatment than in the other groups (p<0.05). Hence, $NH_3$-N concentrations in liquid phases were increased (p<0.05) from 12 to 24 h, but the trend was lowest in FA4 than in the other groups at both stages. The total VFA production was comparatively lower and butyrate levels were moderate in FA4 group than in the the other groups during both stages (p<0.05). Indirect odor-reducing compounds such as $NO_2$, $NO_3$ and $SO_4$ concentrations were higher in the FA4 and FA3 than in the other groups at 24 h (p<0.05). After fermentation, ten dominant bands appeared, six of which appeared in all samples and four in only the FA4 treated group. The total number of DGGE bands and diversity was higher in the FA4-group compared to other groups. Additionally, similarity indices were lowest (71%) in the FA4, which represented a different bacterial community compared with the other groups. These findings indicate that $NH_3$-N, $H_2S$ and VFA production was minimal, and pH was also better in the FA4 group than in the other groups. Furthermore, the conversion of odor-reducing indirect compounds or their intermediates was higher in the FA4 group in compared to the other groups. FA4 group generated less odorous products and more indirect products by in vitro fermentation at 24 h, and their microbial pattern appeared to differ from that of the other groups. These findings suggest that this particular FA could change the microbial population, which may have a beneficial effect on odor reduction. It is recommended that the oregano lippia may be supplied to growing pigs as FA along with excess carbohydrate sources to reduce the production of odorous compounds.

• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.204-212
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• 2009

A strain producing ${\alpha}$-galactosidase and ${\beta}$-glucosidase was isolated from Kimchi. The isolated strain was identified as Weissella cibaria by 16S rDNA analysis and designated as Weissella cibaria K-M1-4. The enzyme activity of ${\alpha}$-galactosidase and ${\beta}$-glucosidase reached the maximum in the soy medium at $37^{\circ}C$ for 24 hr. The enzymes were purified by ethanol fractionation, DEAE sepharose fast flow, and sephacryl S-100HR column chromatography. ${\alpha}$-Galactosidase specific activity was shown by 576 Units/mg protein and the yield was 3.5% of the total activity of crude extracts. ${\beta}$-glucosidase specific activity was shown by 480 Units/mg protein and the yield was 2.9% of the total activity of crude extracts. The optimum temperature for ${\alpha}$-galactosidase was $60^{\circ}C$ and 43% of its original activity remained when it was treated at $80^{\circ}C$ for 30 min. For ${\alpha}$-galactosidase shows the optimum pH of 8.0 and is fairly stable between pH5.0 and pH9.0. The enzyme activity was increased in the presence of $Fe^{2+}$ and $Cu^{2+}$. The value of Km and Vmax for the enzyme were 0.98 mM and $1.81{\mu}$mole/min, respectively. The ${\beta}$-glucosidase has the optimum temperature of $50^{\circ}C$ and 46% of its original activity remained when it was treated at $80^{\circ}C$ for 30min. Its optimum pH of 7.0 and is fairly stable between pH5.0 and pH9.0. The enzyme activity was increased in the presence of $Fe^{2+},\;Co^{2+}$ and $Cu^{2+}$. The value of Km and Vmax for the enzyme were 1.24 mM and $6.81{\mu}$mole/min, respectively.

• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.304-313
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• 2016

One of the issues currently facing nuclear power plants is how to store spent nuclear waste materials which are contaminated with radionuclides such as $^{134}Cs$, $^{135}Cs$, and $^{137}Cs$. Bioremediation processes may offer a potent method of cleaning up radioactive cesium. However, there have only been limited reports on $Cs^+$ tolerant bacteria. In this study, we report the isolation and identification of $Cs^+$ tolerant bacteria in environmental soil and sediment. The resistant $Cs^+$ isolates were screened from enrichment cultures in R2A medium supplemented with 100 mM CsCl for 72 h, followed by microbial community analysis based on sequencing analysis from 16S rRNA gene clone libraries(NCBI's BlastN). The dominant Bacillus anthracis Roh-1 and B. cereus Roh-2 were successfully isolated from the cesium enrichment culture. Importantly, B. cereus Roh-2 is resistant to 30% more $Cs^+$ than is B. anthracis Roh-1 when treated with 50 mM CsCl. Growth experiments clearly demonstrated that the isolate had a higher tolerance to $Cs^+$. In addition, we investigated the adsorption of $0.2mg\;L^{-1}$ $Cs^+$ using B. anthracis Roh-1. The maximum $Cs^+$ biosorption capacity of B. anthracis Roh-1 was $2.01mg\;g^{-1}$ at pH 10. Thus, we show that $Cs^+$ tolerant bacterial isolates could be used for bioremediation of contaminated environments.

• Food Science and Preservation
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• v.22 no.6
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• pp.920-925
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• 2015

The microbial composition in Nuruk, a Korean cereal fermentation starter, is a critical factor for the quality and organoleptic properties of traditional alcoholic beverages. This study was aimed at monitoring the compositional change and enzyme activity of culturable lactic acid bacteria (LAB) in two types of Nuruk fermented at different temperatures. All culturable LAB were isolated at various time points (0, 3, 6, 10, 20, and 30 days) and identified by 16S rRNA sequencing. In traditional Nuruk type A (TN-A), which was fermented at $36^{\circ}C$, the population of total culturable LAB during the fermentation period was between $10^4$ and $10^5$ log CFU/mL. On the other hand, the LAB population in traditional Nuruk type B (TN-B) fermented at $45^{\circ}C$ (primary fermentation for 10 days) and $35^{\circ}C$ (secondary fermentation for 20 days) was $10^2$ log CFU/mL; however, these bacteria could not be detected after 6 days. Major LAB strains were identified in both Nuruk types: (1) from the MRS-culture of TN-A, Pediococcus pentosaceus at 3-30 days; (2) from MRS-culture of TN-B, P. pentosaceus at 3 days and Enterococcus hirae at 6 days. The protease activities of the dominant LAB isolated from the TN-A and TN-B cultures were within the ranges of 0.64~1.03 mg/mL and 0.74~0.81 mg/mL (tyrosine content), respectively, whereas the ${\alpha}$-amylase activities were 0.75~0.98 mg/mL and 0.78~0.79 mg/mL (amylose content), respectively.