• The Plant Pathology Journal
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• v.21 no.1
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• pp.68-72
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• 2005

The production of antibiotic substances by Serratia plymuthica A21-4 was greatly enhanced by modifying components of a growth medium. When the minimal medium containing $K_2HPO_4$ 0.7%, $KH_2PO_4$ 0.2%, $(NH_4)_2SO_4$ 0.1%, $MgSO_4$ 0.01% was used as basal medium, the best carbon source for antibiotic production was glycerol and the most favorable nitrogen source was ammonium sulfate. The modified medium for antibiotic production also increased colonization ability of A21-4 on pepper root and in the rhizosphere soil. When the cells of A21-4 were suspended in modified medium, the population density of A21-4 on pepper root was 10-100 times higher than that suspended in 0.1 M $MgSO_4$. The population density of A21-4 on root did not decrease under $10^6$ cfu/groot up to 21 days after treatment although the inoculum of A21-4 was reduced to $10^7$ cell/ml. Similar tendency was also observed in the rhizosphere soil. Consequently, Phytophthora blight of pepper was successfully controlled by A21-4 with $10^7$ cell/ml suspended in the modified buffer solution instead of $10^9$ cfu/ml suspended in 0.1 M $MgSO_4$.

• Food Science of Animal Resources
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• v.26 no.3
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• pp.402-409
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• 2006

Although microorganisms are, in fact, the most diverse and abundant type of organism on Earth, the ecological functions of microbial populations remains poorly understood. A variety of bacteria including marine Vibrios encounter numerous ecological challenges, such as UV light, predation, competition, and seasonal variations in seawater including pH, salinity, nutrient levels, temperature and so forth. In order to survive and proliferate under variable conditions, they have to develop elaborate means of communication to meet the challenges to which they are exposed. In bacteria, a range of biological functions have recently been found to be regulated by a population density-dependent cell-cell signaling mechanism known as quorum-sensing (QS). In other words, bacterial cells sense population density by monitoring the presence of self-produced extracellular autoinducers (AI). N-acylhomoserine lactone (AHL)-dependent quorum-sensing was first discovered in two luminescent marine bacteria, Vibrio fischeri and Vibrio harveyi. The LuxI/R system of V. fischeriis the paradigm of Gram-negative quorum-sensing systems. At high population density, the accumulated signalstrigger the expression of target genes and thereby initiate a new set of biological activities. Several QS systems have been identified so far. Among them, an AHL-dependent QS system has been found to control biofilm formation in several bacterial species, including Pseudomonas aeruginosa, Aeromonas hydrophila, Burkholderia cepacia, and Serratia liquefaciens. Bacterial biofilm is a structured community of bacterial cells enclosed in a self-produced polymeric matrix that adheres to an inert or living surface. Extracellular signal molecules have been implicated in biofilm formation. Agrobacterium tumefaciens strain NT1(traR, tra::lacZ749) and Chromobacterium violaceum strain CV026 are used as biosensors to detect AHL signals. Quorum sensing in lactic acid bacteria involves peptides that are directly sensed by membrane-located histidine kinases, after which the signal is transmitted to an intracellular regulator. In the nisin autoregulation process in Lactococcus lactis, the NisK protein acts as the sensor for nisin, and NisR protein as the response regulator activatingthe transcription of target genes. For control over growth and survival in bacterial communities, various strategies need to be developed by which receptors of the signal molecules are interfered with or the synthesis and release of the molecules is controlled. However, much is still unknown about the metabolic processes involved in such signal transduction and whether or not various foods and food ingredients may affect communication between spoilage or pathogenic bacteria. In five to ten years, we will be able to discover new signal molecules, some of which may have applications in food preservation to inhibit the growth of pathogens on foods.

• The Journal of the Korean Society for Microbiology
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• v.9 no.1
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• pp.41-45
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• 1974

On day 2 after treatment of Lewis rat with 25mg of hydrocortisone, the cell number in the thymus was reduced to less than 10% of the matched control. By day 12 after hydrocortisone treatment the thymic cell population was recovered almost its original value and on day 24 after treatment the number of thymocytes was equivalent to that of normal thymocytes. The density distribution profile of hydrocortisone treated rats as compared with normal rats showed a marked decrease in the denser fraction D while the lighter fractions. (A plus B, and C) showed a considerable proportional increase. The proportion of dead cells in thymus suspension from hydrocortisone treated rats was higher than that from their normal counterparts. On separation, the dead cells accumulated selectively in the pellet and A fraction. The response of the thymocytes from hydrocortisone treated rats to PHA was increased compared to that from normal rats. Among the subpopulations, D fraction, which was relatively unresponsive in normal rats, showed a marked increase in PHA response and C fraction showed some increase in the response.

• Journal of Microbiology
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• v.37 no.1
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• pp.1-9
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• 1999

The Biolog redox technology was carried out for evaluation of acidification effect on microbial communities at each stage of pH gradient microcosm. While the number of heterotrophic bacterial population and activities of extracellular enzyme decreased as the pH decreased, the number of total bacteria in the microcosm was not affected. The average color development of sample at each pH-gradient showed a sigmoidal curve, and at higher pH, more overall color development appeared in Biolog plates. Average color development value in Biolog plates was stabilized at 50 hours as an optimum incubation time. The color production in the Biolog plates was caused by cell density at above pH 5.0, but by cell activity below pH 4.0. Principal component analysis of color responses revealed distinctive patterns among the pH-gradient microcosm samples.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.2
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• pp.83-87
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• 2008

The fyn-related kinase (FRK) belongs to the tyrosine kinase family of protein kinases. Recent studies have shown that Frk affects pancreatic beta cell number during embryogenesis and promotes beta cell cytotoxic signals in response to streptozotocin. To investigate the genetic association between FRK polymorphisms and the risk of obesity in Korean population, single nucleotide polymorphisms (SNPs) in the FRK gene region were selected and analyzed. The body mass index (BMI) was calculated, and biochemical data (systolic blood pressure, diastolic blood pressure, hemoglobin A1C, triglyceride, total cholesterol, high density lipoprotein, and low density lipoprotein) of blood sample from each subject were also measured. One hundred fifty five healthy control and 204 overweight/obesity subjects were recruited. Genotype frequencies of six SNPs [rs6568920 (+8391G>A), rs3756772 (+56780A>G), rs3798234 (+75687C>T), rs9384970 (+68506G>A), rs1933739 (+72978G>A), and rs9400883 (+75809A>G)] in the FRK gene were determined by Affymetrix Targeted Genotyping Chip data. According to the classification of Korean Society for the Study of Obesity, control (BMI 18 to < 23) and overweight/obesity (BMI$\geq$23) subjects were recruited. For the analysis of genetic data, EM algorithm, SNPStats, Haploview, HapAnalyzer, SNPAnalyzer, and Helixtree programs were used. Multiple logistic regression analysis (codominant, dominant, and recessive models) was performed. Age and gender as covariates were adjusted. For biochemical data, Student's t test was used. The mean value of BMI in the control and overweigh/obesity groups was 21.1${\pm}$1.2 (mean${\pm}$SD) and 25.6${\pm}$2.0, respectively. All biochemical data of the overweight/obesity group were statistically significance, compared with the control group. Among six SNPs, two linkage disequilibrium (LD) blocks were discovered. One block consisted of rs1933739 and rs9400883, and the other comprised rs3756772 and rs3798234. One SNP (rs9384970, +68506G>A) showed an association with overweight/obesity in the codominant model (p=0.03). Interestingly, the AA genotype distribution in the overweight/obesity group (n=7, 3.5%) was higher than those in the control group (n=1, 0.6%), which is not found in either Japanese or Chinese subjects. Therefore, the AA genotype of rs9384970 may be a risk factor for development of obesity in Korean population. The results suggest that FRK may be associated with overweight/obesity in Korean population.

• Development and Reproduction
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• v.12 no.1
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• pp.51-56
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• 2008

To optimize the cell culture conditions of zebrafish embryonic cells, we compared the efficiency of three types of medium, DMEM, K-NAC and D-NAC. In this study, we showed that the cells grown in K-NAC have better plating efficiency than DMEM, especially in the case of low cell seeding density. However, cells grew slower in K-NAC than those in DMEM in confluent cultures. The effect of 0.1% zebrafish embryo extracts was minimal. The presence of 1% trout serum in culture medium significantly increased the growth rate of cells(p<0.05). No difference was found at $2{\sim}3{\times}10^5$ cell seeding density(p<0.05). At $4{\sim}5{\times}10^5$ cell seeding density, cells grew better in DMEM than K-NAC (p<0.1). The results suggest that supplementation of NAC and A2P in Keratinocyte SFM may improves plating efficiency when cells are plated at low population. No difference was found for cell growth in either medium with 5%, 10% or 15% FBS supplemented (p<0.05). Cells culture in D-NAC grew significantly better than those in DMEM(p<0.05). Our results clearly showed that the use of NAC and A2P in the culture medium has a positive effect on cell growth regardless of the amount of FBS added.

• Ocean Science Journal
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• v.43 no.1
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• pp.49-59
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• 2008

To examine the population development of the dinoflagellates, Ceratium furca and Ceratium fusus, daily field monitoring was conducted between April and July 2003 in the temperate coastal water of Sagami Bay, Japan. During the study period, the concentrations of C. furca were always lower than those of C. fusus. A sharp increase in the densities of both species was recorded on 5 May showing the maximum cell concentrations (C. furca = $14,800\;cells\;L^{-1}$, C. fusus = $49,600\;cells\;L^{-1}$). In the 7 days prior to the May bloom of the Ceratium species (29 April to 1 May), the highest density of the heterotrophic dinoflagellate Noctiluca scintillans was observed. Additionally, a second bloom of C. fusus occurred on 22 July. Here, two causes of the significant increases in the Ceratium populations during the two blooming periods (first time; 1 to 8 May, second time; 15 to 22 July) are presented. First, an increase in the nutrients of the surface layer regenerated by the breakdown of blooms by N.scintillans could be considered as a major cause of the population increase of the two Ceratium species. Second, a decrease in salinity (to 27 psu) was correlated with the later bloom of C. fusus. These results suggest that the population development of the two Ceratium species requires nutrients regenerated after the reduction of the diatom population by N. scintillans and, for C. fusus, continuous low salinity conditions, compared to other environmental factors during the rainy season.

• Journal of Ginseng Research
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• v.36 no.1
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• pp.78-85
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• 2012

Endothelial progenitor cells (EPC) are a population of cells that circulate in the blood stream. They play a role in angiogenesis and, therefore, can be prognostic markers of vascular repair. Ginsenoside $Rg_3$ prevents endothelial cell apoptosis through the inhibition of the mitochondrial caspase pathway. It also affects estrogen activity, which reduces EPC senescence. Sun ginseng (SG), which is heat-processed ginseng, has a high content of ginsenosides. The purpose of this study was to investigate the protective effects of SG on senescence-associated apoptosis in EPCs. In order to isolate EPCs, mononuclear cells of human blood buffy coats were cultured and characterized by their uptake of acetylated low-density lipoprotein (acLDL) and their binding of Ulex europaeus agglutinin I (ulex-lectin). Flow cytometry with annexin-V staining was performed in order to assess early and late apoptosis. Senescence was determined by ${\beta}$-galactosidase (${\beta}$-gal) staining. Staining with 4'-6-Diamidino-2-phenylindole verified that most adherent cells (93${\pm}$2.7%) were acLDL-positive and ulex-lectin-positive. The percentage of ${\beta}$-gal-positive EPCs was decreased from 93.8${\pm}$2.0% to 62.5${\pm}$3.6% by SG treatment. A fluorescence-activated cell sorter (FACS) analysis showed that 4.9% of EPCs were late apoptotic in controls. Sun ginseng decreased the apoptotic cell population by 39% in the late stage of apoptosis from control baseline levels. In conclusion, these results show antisenescent and antiapoptotic effects of SG in human-derived EPCs, indicating that SG can enhance EPC-mediated repair mechanisms.

• 한국해양학회지
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• v.24 no.3
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• pp.157-164
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• 1989

Quantitative species distribution and primary productivity of phytoplankton were studied monthly from August, 1987 to July, 1988 along with the quantitative distribution of total heterotrophic bacterioplankton and three groups of physiologically chracteristic bacterioplankton in the intertidal and subtidal waters off Kum River Estuary, Yellow Sea. A total of 121 phytoplankton taxa including 102 diatoms occurred, and cell concentration ranged from 15 to 5451 (cells/ml). The great spatio-temporal variations of the number of phytoplankton species and cell concentration well reflected the environmental differences between the intertidal and subtidal waters. Primary productivity (in Piopt, mgC/$m^3$/hr) ranged from 0.6 to 27.3. Just after the phytoplankton bloom (March) Piopt was very low in April at station 1, where amylolytic bacterioplankton also showed quite low population density. The peaks of primary productivity were not always coincided with those of phytoplankton standing crop. The ratio of Piopt's between samples well indicated the environmental differences between the intertidal and subtidal waters. Little characteristic trend was found in the scatter diagrams of phytoplankton standing crop along the population densities of total heterotrophic bacterioplankton and the three groups of physiologically characteristic bacterioplankton. In summer the phytoplankton standing crop was minimum in contrast with the high population density of bacterioplankton, which implies the influx of much allochthonous orgainc matter from Kum River. The scatter diagrams of Piopt along bacterioplankton population density revealed some phenomena there. Piopt had highly positive correlation with the population density of amylolytie bacterioplankton($R^2$=0.84) and that of lipolytic bacterioplankton($R^2$=0.70) while total heterotrophic bacterioplankton and proteolytic bacterioplankton had lesser correlations with Piopt. From the regression lines the increase of unit Piopt (mgC/$m^3$/hr) in the study area was calculated to mean the increase of $9.0{\times}10$ cells/ml and $8.0{\times}10$ cells/ml of amylolytic bacterioplankton and lipolytic bacterioplankton, respectively.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.2
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• pp.436-441
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• 2006

Rheumatoid arthritis is a chronic, systemic, and inflammatory autoimmune disorder that affects 1% of the adult population worldwide. Osteoarthritis is a multifactorial disease with high morbidity that is characterized by degradation of the matrix and destruction of articular cartilage. In this study, we examined the inhibition effect of Trachelospermi Caulis on the inflammation($TNF-{\alpha}$, $IL-1{\beta}$, NO), cartilage protection(MMP-13), and cell death in arthritis. RAW 264.7 and SW 1353 cells were cultivated in DMAE(GibcoBRL, USA) with 5% FBS and Fungizone in $37^{\circ}C$, 5% CO2. THP-1 cells were cultivated in RPMI(GibcoBRL, USA) with 5% FBS and Fungizone in $37^{\circ}C$, 5% CO2. Activity of caspase-3, XIAP, Cytochrome C in the cell was examined by using western blot. The results obtained were as Follows; Concentration of nitric oxide in Trachelospermi Caulis treatment group significantly decreased compared with that of non-treatment group (P<0.05). In treated group, Concentration of Trachelospermi Caulis was not significantly associated with cell death. Concentration of $TNF-{\alpha}$ and $IL-1{\beta}$ in Trachelospermi Caulis treatment group decreased significantly compared with that of none treatment group (P<0.05). Relative density of MMP-13 in Trachelospermi Caulis treatment group decreased significantly compared with that of none treatment group and dose-response relationship was observed. After treatment of staurosporin in SW1353 which increases cell death, in Trachelospermi Caulis treated group, the cell death was effectively decreased. In conclusion, these results suggest that Trachelospermi Caulis inhibit inflammation and cell death in arthritis. More researches about effect of Trachelospermi Caulis are considered to need.