• Korean Journal of Microbiology
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• v.52 no.4
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• pp.428-436
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• 2016

The emergence of antibiotic-resistant bacteria has been increased and become a public health concern worldwide. Many bacterial infections can be sequentially treated with different types of antibiotics. Thus, this study was designed to evaluate the changes in survival, antibiotic susceptibility, mutant frequency, ${\beta}$-lactamase activity, biofilm formation, and gene expression in Klebsiella pneumoniae after exposure to sequential antibiotic treatments of ciprofloxacin and meropenem. Treatments include control (CON; no addition), 1/2 MIC ciprofloxacin addition (1/2CIP), 2 MIC ciprofloxacin addition (2CIP), initial 1/2 MIC ciprofloxacin addition followed by 1/2 MIC meropenem (8 h-incubation) and 2 MIC ciprofloxacin (16 h-incubation) (1/2CIP-1/2MER-2CIP), initial 1/2 MIC ciprofloxacin addition followed by 1/2 MIC meropenem (8 h-incubation) and 2 MIC meropenem (16 h-incubation) (1/2CIP-1/2MER-2MER), and initial 1/2 MIC ciprofloxacin addition followed by 2 MIC ciprofloxacin(8 h-incubation) and 2 MIC meropenem(16 h-incubation) (1/2CIP-2CIP-2MER). No growth of K. pneumoniae was observed for the 2CIP throughout the incubation period. The numbers of planktonic cells varied with the treatments (7~10 log CFU/ml), while those of biofilm cells were not significantly different among treatments after 24-h incubation, showing approximately 7 log CFU/ml. Among the sequential treatments, the least mutant frequency was observed at the 1/2CIP-1/2MER-2CIP (14%). Compared to the CON, 1/2CIP-2CIP-2MER decreased the sensitivity of K. pneumoniae to piperacillin, cefotaxime, and nalidixic acid. The highest ${\beta}$-lactamase activity was 22 nmol/min/ml for 1/2CIP-1/2MER-2CIP, while the least ${\beta}$-lactamase activity was 6 nmol/min/ml for 1/2CIP-2CIP-2MER. The relative expression levels of multidrug efflux pump-related genes (acrA, acrB, and ramA) were increased more than 2-fold in K. pneumoniae exposed to 1/2CIP-1/2MER-2MER and 1/2CIP-2CIP-2MER. The results suggest that the sequential antibiotic treatments could change the antibiotic resistance profiles in K. pneumoniae.

• Journal of Korean Society of Forest Science
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• v.39 no.1
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• pp.47-56
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• 1978

This study aimed to know difference in freezing resistance among different clonal seedlings or different seed source seedlings of Cryptomeria japonica which has been selected where extreme cold prevails in Korea and Japan. The freezing resistance of three 12-50 year old trees was also measured in the experiment. The freezing resistance was measured in different tissue parts: mainly leaf, cambiam and xylem, at three different collection dates in two different collection places during the winter of 1977-1978. The following results and discussions were made: 1. The clonal difference in freezing resistance of Cryptomeria japonica was $9^{\circ}$ to $15^{\circ}C$ in maximum according to the collection place. However, the clonal difference in freezing resistance was not related to the difference in climatic conditions where the parent tree have been growing. This impiled that the natural selection of cold resistant genes in Cryptomeria japonica has not reached its evolutional equilibrium yet since most of the Cryptomeria forest has been established by artificial regeneration. 2. The difference in freezing resistance among leaf, cambium and xylem was not apparent except that leaf of several clones showed higher freezing resistance than cambium or xylem when they collected at mid-winter. The least freezing resistant tissue part, thought its freezing resistance was not measure in all clones and all temperatures were appeared in the apical buds. The new shoot growth was observed in the next spring with being replaced by its dormant or adventitious bud growth when the apical bud was injured dy cold during winter. 3. The freezing resistance of leaf, cambium and xylem was shown high enough so that freezing resistance Cryptomeria clones in this experiment were supposed to be able to survive in cold winter conditions at the middle part of Korea. However, it was reported that the most susceptible tissue part to winter injury was the basal stem, but of which freezing resistance was not-measured in this experiment. Several silvicultural methods for prevention of Cryptomeria seedlings from cold damage were discussed in literature.

• Journal of Oral Medicine and Pain
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• v.38 no.3
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• pp.221-233
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• 2013

Bile acids are polar derivatives of cholesterol essential for the absorption of dietary lipids and regulate the transcription of genes that control cholesterol homeostasis. Recently it have been identified the synthetic chenodeoxycholic acid (CDCA) derivatives HS-1200 and cisplatin showed apoptisis-inducing activity on various cancer cells in vivo and in vitro. This study was undertaken to investigate the synergistic apoptotic effect of co-treatment with HS-1200 and cisplatin on human tongue squamous cell carcinoma cells (SCC25 cells). To investigate whether the co-treatment with HS-1200 and cisplatin compared to each single treatment efficiently reduces the viability of SCC25 cells, MTT assay was conducted. The induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining and an analysis DNA hypoploidy. Westen blot analysis and immunofluorescent staining were also performed to evaluate the expression levels and the translocation of apoptosis-related proteins following this co-treatment. Furthermore, proteasome activity and mitochondrial membrane potential (MMP) change were also assayed. In this study, co-treatment with HS-1200 and cisplatin on SCC25 cells showed several lines of apoptotic manifestation such as nuclear condensations, DNA fragmentation, reduction of MMP and proteasome activity, the increase of Bax and the decrease of Bcl-2, decrease of DNA content, the release of cytochrome c into cytosol, translocation of AIF and DFF40 (CAD) onto nuclei, and activation of caspase-9, caspase-7, caspase-3, PARP and DFF45 (ICAD) whereas each single treated SCC25 cells did not show these patterns. Although the single treatment of $25{\mu}M$ HS-1200 and $4{\mu}g/ml$ cisplatin for 24 h did not induce apoptosis, the co-treatment of these reagents prominently induced apoptosis. Therefore our data provide the possibility that the combination therapy with HS-1200 and cisplatin could be considered as a novel therapeutic strategy for human squamous cell carcinoma.

• Journal of Genetic Medicine
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• v.5 no.2
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• pp.139-144
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• 2008

We report on two cases of pericentric inversion of X chromosome. The cases were found in a 40-year-old man with azoospermia and in a family of a 38-year-old pregnant woman. The first case with 46,Y,inv(X)(p22.1q27) had concentrations of LH, prolactin, estradiol, and testosterone that were within normal ranges; however, FSH levels were elevated. Testis biopsy revealed maturation arrest at the primary and secondary spermatocytes without spermatozoa. There were no microdeletions in the 6 loci of chromosome Y. For the second case, the cytogenetic study of thepregnant woman referring for advanced maternal age and a family history of inversion X chromosome was 46,X,inv(X)(p22.11q27.2). The karyotype of her fetus was 46,X,inv(X)(p22.1q27). Among other family members, the karyotypes of an older sister in pregnancy and her fetus were 46,X,inv(X)(p22.11q27.2), and 46,Y,?inv(X), respectively. The proband's father was 46,Y,inv(X)(p22.11q27.2). All carriers in the family discussed above were fertile and phenotypically normal. In addition, the ratio of inactivation of inv(X) by RBG-banding was discordant between the two sisters, with the older sister having only 4.1% of cells carrying inactivated inv(X) while the proband had a 69.5% incidence of late replicating inv(X). Therefore, we suggest that the cause of azoospermia in the first case might be related to inversion X chromosome with positional effect. Also, the family of the second case showing normal phenotype of the balanced inv(X) might be not affected any positional effect of genes.

• Journal of Mushroom
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• v.13 no.3
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• pp.217-222
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• 2015

This study was conducted to obtain a growth correlation of basal information from the development of disease resistant Flammulina velutipes cultivars through back-crossing between the strains of wild-type brown monokaryon 4019-20 and the derivative of commercial quality white monokaryons 3. The two strains were selected to back-cross for further enhancing their latent attributes and growth characteristics. The parents of 4019-$20{\times}M3$ back-crossed to reproduce $F_1$, M3-Sn. Using $F_1$, M3-Sn procured and isolated into 94 monokaryon strains. Further examination of growth characteristics carried out by back-crossing between M3 and $BC_1F_1$ from M3-n dikaryon. Monokaryon exhibited an irregular growth pattern and demonstrated to be sluggish development in the sawdust medium. However $BC_1F_1$(M3-n) dikaryon strains confirmed mostly regular growth pattern and demonstrated ordinary growth in the sawdust medium. The fruitbody of $BC_1F_1$ confirmed as light-brown colour to be the dominant gene. The colour distributions of fruitbody, $BC_1F_1$, resulted as follows; 7% of dark brown, 25% of brown, 27% of light brown, 16% of ivory and 25% of white. The ratio of the other color to white showed 3 to 1 which suggested two major genes were related to fruitbody color.

• Journal of Life Science
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• v.28 no.4
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• pp.435-443
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• 2018

AMP-activated protein kinase (AMPK) functions as a metabolic master through regulating and restoring cellular energy balance. In skeletal muscle, AMPK increases myofibril protein degradation through the expression of muscle-specific ubiquitin ligases. Mori Folium, the leaf of Morus alba, is a traditional medicinal herb with various pharmacological functions; however, the effects associated with muscle atrophy have not been fully identified. In this study, we confirmed the effects of AMPK activation by examining the effects of 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an activator of AMPK, on the induction of atrophy and expression of atrophy-related genes in C2C12 myotubes. We also investigated the effects of the ethanol extract of Mori Folium (EEMF) on the recovery of AICAR-induced muscle atrophy in C2C12 myotubes. It was found that exposure to AICAR resulted in the stimulation of Forkhead box O3a (FOXO3a); an up-regulation of muscle-specific ubiquitin ligases such as Muscle Atrophy F-box (MAFbx)/atrogin-1 and muscle RING finger-1 (MuRF1), and a down-regulation of muscle-specific transcription factors, such as MyoD and myogenin; with the activation of AMPK. In addition, AICAR without cytotoxicity indicated a decrease in diameter of C2C12 myotubes. However, treatment with EEMF significantly suppressed AICAR-induced muscle atrophy of C2C12 myotubes in a dose-dependent manner as confirmed by a decrease in myotube diameter, which is associated with a reversed stimulation of FOXO3a by the inhibition of AMPK activation. These results indicate that the activation of AMPK by AICAR induces muscle atrophy, and EEMF has preeminent effects on the inhibition of AICAR-induced muscle atrophy through the AMPK signaling pathway.

• Korean Journal of Environment and Ecology
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• v.30 no.4
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• pp.694-704
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• 2016

Various infectious and parasitic diseases are known to be the main factors that cause decline in the global amphibian population. In Korea, commercial frog farms have been running since 2005. However, until now, studies on diseases including studies on parasitic diseases that occur in farm frogs have not been conducted. In this study, we studied and compared the acanthocephalan infection rates and the number of parasites in the body cavity, stomach, and small and large intestines of the Dybowskii's brown frogs collected from inside and outside the frog farms in Inje, Goesan, Gongju and Boryeong. In addition, we classified the acanthocephalan parasites into genera by analyzing their nuclear 18S rRNA genes. On an average, 51.7% of the investigated frogs were infected by acanthocephalans, which belong to the Centrorhynchus genus. The infection rate of the frogs collected in the Inje farm was 15%, significantly lower than those from the Goesan, Gongju and Boryeong farms. The rate in Goesan was 55%, which is lower than Gongju (80%) and Boryeong (90%) although it is not statistically significant. No difference was found in the infection rate and in the number of parasites in male and female frogs and between the groups collected from inside and outside of the farms. The number of infected parasites negatively correlated with the body condition of the frogs. The most parasites were found in the stomach followed by the small and large intestines and the body cavity. This study is the first report on the Centrorhynchus acanthocephalan infection of amphibians in Korea and it suggests the necessity for acanthocephalan parasite management and for conducting further disease-related studies in commercial frog farms.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.91-91
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• 2017

Drought is the most serious abiotic stress limiting rice production. However, little progress has been made in the genetic analysis of drought tolerance, because it is a complex trait controlled by a number of genes and affected by various environmental factors. In here, we screened 218 rice genetic resources for drought tolerance at vegetative stage and selected 32 highly drought tolerant varieties in greenhouse. Under rain-fed conditions, Grain yield of Nagdong was decreased by 53.3% from 517 kg/10a to 241 kg/10a when compare to irrigation condition. By comparison, grain yield of Samgang was decreased by 23.6% from 550 kg/10a to 420 kg/10a. The variety Samgang exhibited strong drought tolerance and stable yield in rain-fed conditions and was selected for further study. To identify QTLs for drought tolerance, we examined visual drought tolerance (VDT) and relative water content (RWC) using a doubled haploid (DH) population consisted of 101 lines derived from a cross between Samgang (a drought tolerance variety) and Nagdong (a drought sensitive variety). Three QTLs for VDT were located on chromosomes 2, 6, and 11, respectively, and explained 41.8% of the total phenotypic variance. qVDT2, flanked by markers RM324 and S2016, explained 8.8% of the phenotypic variance with LOD score of 3.3 and an additive effect of -0.6. qVDT6 was flanked by S6022 and S6023 and explained 12.7% of the phenotypic variance with LOD score of 5.0 and an additive effect of -0.7. qVDT11, flanked by markers RM26765 and RM287, explained 19.9% of the phenotypic variance with LOD score of 7.1 and an additive effect of -1.0. qRWC11 was the only QTL for RWC to be identified; it was in the same locus as qVDT11. qRWC11 explained 19.6% of the phenotypic variance, with a LOD score of 4.0 and an additive effect of 9.7. To determine QTL effects on drought tolerance in rain-fed paddy conditions, seven DH lines were selected according to the number of QTLs they contained. Of the drought tolerance associated QTLs, qVDT2 and qVDT6 did not affect tiller formation, but qVDT11increased tiller number. Tiller formation was most stable when qVDT2 and qVDT11 were combined. DH lines with both of these drought tolerance associated QTLs exhibited the most stable tiller formation. These results suggest that qVDT11 is important for drought tolerance and stable tiller formation under drought stress condition in field.

• Korean Journal of Veterinary Research
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• v.50 no.3
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• pp.213-220
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• 2010

Salmonella (S.) Enterica infection ranks among the most common food borne bacterial infections worldwide. Although there are six subspecies of S. Enterica, the vast majority of human and animal infections are caused by strains belonging to subspecies 1 serovar Typhimurium and Enteritidis. Recent reports on antibiotic resistance of Salmonella spp. are rising steadily. The increasing problem of antibiotic resistance has rekindled interest in bacteriophage to therapy. Therefore, we investigated the efficacy of bacteriophage in S. enterica serovar Enteritidis infected mice and pigs by measuring of body condition, body weight, bacterial colonization and weight of organs based on the in vitro analysis. In vitro experiment, phage cultured with S. Enteritidis showed clear lysis pattern, the plaque forming unit (PFU) of our phage culture was $1.5{\times}10^{11}PFU/mL$, and phage showed its maximum activity at 4 h post inoculation. In mouse experiment, there was no significant difference among experimental groups in the general body conditions and body weight of mice. However, there was difference in weight of liver and spleen depending on the experimental group (p < 0.05). The weight of liver and spleen were reduced by the phage treatment. Also bacterial colonization in spleen and liver were significantly reduced by the phage treatment. In pig experiment, the general body conditions and body temperature exhibited not much difference among the pigs except few pigs in group 3 which showed poor body conditions. From the feces in each group, we could isolate the S. Enteritidis only from group 3. Bacterial enrichment culture was necessary for isolating the bacteria from 5 dpi and 10 dpi, however direct isolation was possible from 15 dpi feces. In phage treated group, postmortem lesion was better than non-phage treated group. Recently, antibiotic resistance concerns on the food-borne bacterial pathogens have been increasing because of the wide spread of the antibiotics resistance genes. This concern is widely transmitted to the human related public health. As one of the alternative treatments on the bacterial pathogens, attempt using phages have been made to control the bacterial diseases. The positive possibility of the trail using phage was observed to control the S. enterica serovar Enteritidis in this study even though the further analysis has been remained.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.2
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• pp.308-319
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• 2003

Mechanical forces are known to have an effect on bone formation, maintenance and remodeling, and there is evidence that the development of the mandibular condyle in the rat or mouse is influenced by altered functional force. However, studies are lacking in molecular-biologic mechanism such as the identification of differentiation factor induced from functional force. Here a mouse model was used to investigate the functional stress-responsive gene or factors which is related to the altered force by comparing the expression genes of functional state and hypo-functional state of the mouse mandible. ICR mice were provisioned with either a soft, mushy diet (soft-diet group) or hard rat pellets (hard-diet group) beginning at weaning for the alteration of functional force and subsequently sacrificed at 89 days of age. Incisor of mice in group 1 were trimmed twice a week to reduce occlusal forces. After killing the animals, mandibular bone including condyle were collected for RNA extraction, subtractive hybridization, northern blot analysis and mRNA in-situ hybridization. The results as follows; 1. A total of 39 clones were sequenced, and 11 individual sequence types were subsequently identified by subtractive hybridization, as 28 clones were represented twice in the analyzed sets. 2. Consequently four candidate clones, FS-s (functional stress-specific)2, -5, -18, and -22 were identified and characterized by homolgy search and northern analysis. Four of these clones, FS-s2, -5, -18, and -22, were shown to be expressed differentially in the hard-diet group. 3. Histologic sections showed that osteoblastic activity along the bone trabeculae and active bone remodeling were significantly lower in soft than in hard diet animals. A soft diet seems to enable a longer period of endochondral ossification in the mandibular condyle. 4. Although the mRNAs of FS-s2, -5, -18, and -22 were expressed rarely by cells of the soft-diet group, highest expression was detected in the cells of the hard-diet group. Together with the above results, it is suggested that FS-s2, -5, -18, and -22 could act as an important factors controlling the tissue changes in response to functional stress. The exact functional significance of these findings remains to be established.