• Asian-Australasian Journal of Animal Sciences
• /
• v.32 no.6
• /
• pp.776-782
• /
• 2019

Objective: Fasting may lead to changes in the microbiota and activity in the rumen. In the present study, the effects of fasting on rumen microbiota and the impact of fasting on in vitro rumen fermentation were evaluated using molecular culture-independent methods. Methods: Three ruminally cannulated Holstein steers were fed rice straw and concentrates. The ruminal fluids were obtained from the same steers 2 h after the morning feeding (control) and 24 h after fasting (fasting). The ruminal fluid was filtrated through four layers of muslin, collected for a culture-independent microbial analysis, and used to determine the in vitro rumen fermentation characteristics. Total DNA was extracted from both control and fasting ruminal fluids. The rumen microbiota was assessed using denaturing gradient gel electrophoresis (DGGE) and quantitative polymerase chain reaction. Microbial activity was evaluated in control and fasting steers at various intervals using in vitro batch culture with rice straw and concentrate at a ratio of 60:40. Results: Fasting for 24 h slightly affected the microbiota structure in the rumen as determined by DGGE. Additionally, several microorganisms, including Anaerovibrio lipolytica, Eubacterium ruminantium, Prevotella albensis, Prevotella ruminicola, and Ruminobacter amylophilus, decreased in number after fasting. In addition, using the ruminal fluid as the inoculum after 24 h of fasting, the fermentation characteristics differed from those obtained using non-fasted ruminal fluid. Compared with the control, the fasting showed higher total gas production, ammonia, and microbial protein production (p<0.05). No significant differences, however, was observed in pH and dry matter digestibility. Conclusion: When in vitro techniques are used to evaluate feed, the use of the ruminal fluid from fasted animals should be used with caution.

• Applied Chemistry for Engineering
• /
• v.30 no.2
• /
• pp.233-240
• /
• 2019

Molecular recognition technology has attracted considerable attention for improving the selectivity of a specific molecule by imprinting it on a polymer matrix. In this study, adsorption and release characteristics of chitosan based drug delivery films imprinted with sulindac (SLD) were investigated in terms of the plasticizer, temperature and pH and the results were also interpreted by the related mathematical models. The adsorption characteristics of target molecules on SLD-imprinted polymer films were better explained by the Freundlich and Sips equation than that of the Langmuir equation. The binding site energy distribution function was also useful for understanding the adsorption relationship between target molecules and polymer films. The drug release of SLD-imprinted polymer films followed the Fickian diffusion mechanism, whereas the drug release using artificial skin followed the non-Fickian diffusion behavior.

• Journal of fish pathology
• /
• v.36 no.2
• /
• pp.403-408
• /
• 2023

Mullet is an important marine aquaculture fish species in Korea, with a total of 7,237 tons produced as of 2022, making it the 5th most produced marine aquaculture fish species. In this study, ectoparasites presumed to be isopods were discovered in the fins of farmed flathead grey mullet (average weight 550 g), and the characteristics of the parasites were confirmed. The length of the parasite was 5 to 18 mm, and 3 to 7 parasites were infected per fish. To analyze the characteristics of the parasites, molecular biological identification and phylogenetic analysis were performed using the cytochrome c oxidase subunit I (COI) gene, and it was confirmed to be most closely related to Nerocila japonica in the Cymothoidae family. To confirm the parasite control effect, a direct exposure drug sensitivity test was conducted on five types of aquatic drugs and fresh water, trichlorfon was confirmed to be effective.

• The Korean Journal of Mycology
• /
• v.52 no.2
• /
• pp.145-153
• /
• 2024

While investigation of the fungal diseases on apples collected from Cheongsong-gun and Bonghwa-gun in Gyeongbuk province, Korea, between August and September 2023 isolated five fungal strains from fruits with sooty blotch and flyspeck (SBFS) disease. The strains were designated as KNUF-23-CS02, KNUF-23-CS-06, KNUF-23-CS12, KNUF-23-BH01, and KNUF-23-BH03. When grown on potato dextrose agar and 2% water agar, the cultural characteristics of the strains were similar to those previously reported characteristics of Peltaster fructicola Pf001. The strains produced monoblastic, hyaline conidiogenous cells; the conidia were hyaline, unicellular, cylindrical to ovoidal, and 3.5-7×1.7-3.9 and 4.0-6.6×1.8-3.2 μm in size on synthetic nutrient-poor agar or water agars, respectively. Secondary conidia production by microcyclic conidiation and budding was observed. The KNUF-23-BH03 strain was shown to cause SBFS symptoms similar to those observed on the apples in the pathogenicity test. Molecular phylogenetic analyses were conducted based on the isolated species sequences of the internal transcribed spacer region, nuclear large ribosomal DNA subunit, and mitochondrial small ribosomal RNA subunit gene. The five strains were clustered with Peltaster fructicola Pf001. Based on the cultural and morphological characteristics and phylogenetic analysis, the five strains were identified as Peltaster fructicola, which has not been previously reported in Korea.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.25 no.1
• /
• pp.45-57
• /
• 2015

Objectives: This study aims to compare the physicochemical characteristics, toxicological data with Occupational Exposure Limits (OELs) of chemicals under the Occupational Safety and Health Act(OSHA) regulated by the Ministry of Employment and Labor of Korea. Methods: Information on chemicals which have OELs on physicochemical characteristics and toxicological data was collected using Material Safety Data Sheet(MSDS) from Korea Occupational Safety and Health Agency(KOSHA) and the Korea Information System for Chemical Safety Management(KISChem) in 2014. Statistical analyses including correlation and simple regression were performed to compare the OELs with chemical characteristics including molecular weight, boiling point, odor threshold, vapor pressure, vapor density, solubility and octanol-water partition coefficient(OWPC) and toxicological data such as median lethal dose($LD_{50}$) and median lethal concentration($LC_{50}$). Results: A total of 656 chemicals have OELs under OSHA in Korea. The numbers of chemicals which have eight-hour time weighted average(TWA) and short term exposure limits(STEL) are 618 and 190, respectively. TWA was significantly correlated with boiling point and STEL was only correlated with vapor pressure among physicochemical characteristics. Solubility and OWPC between "skin" and "no skin" substances which indicate skin penetration were not significantly different. Both $LD_{50}$ and $LC_{50}$ were correlated with TWA, while the $LC_{50}$ was not with STEL. As health indicators, health rating and Emergency Response Planning Guidelines(ERPG) rating as recommended by the National Fire Protection Association(NFPA) and American Industrial Hygiene Association(AIHA) were associated with OELs and reflect the chemical hazards. Conclusions: We found relationships between OEL and chemical information including physicochemical characteristics and toxicological data. The study has an important meaning for understanding present regulatory OELs.

• KSBB Journal
• /
• v.18 no.6
• /
• pp.522-528
• /
• 2003

The purpose of this study is to inquire into molecular epidemiological characteristics of Vibrio parahaemolyticus. For this study, 120 strains(120 strains of Vibrio parahaemolyticus sampled from diarrhea patients) were examined and analyzed for biochemical characteristics, TDH (thermostable direct hemolysin) antibiotics sensitivity and detection of toxR, gyrE, tdh, and tds gents. G-S PCR (Group Specific Polymerase), PFGE (Pulsed-field Gel Electrophoriesis) methods were performed on the materials from patients were results. 1 Vibrio parahaemolyticus didn't grow in 0% density of NaCl, but the fact was found that those grew in 8% density of NaCl. 2. O：K serotypes of Vibrio parahaemolyticus was turned up in domestic patients was 17 types. Among those O3：K6 was the most, it was 68.3%. 3. In 18 kinds of antibiotic tests resistant against Ampicillin, Ticacillin was comparatively high. the case of resistant against Ampicillin, Ticacillin, Vancomycin at the multiple resistant was 52.5%. 4. Toxin gene tdh had only 109 strains among 120 ones isolated from patients held the genes of 199bp size, and 11 strains was negativity 5. In the test of Kanagawa toxic productivity, 107 strains among strains isolated from patients appeared to be positivity reaction 6. The strain that held trh toxin was only 3, and those among test strains had the genes of 250bp size and that had tdh, trh genes at a time were 3 strains, and TDH toxic productivity of those were 16 times, and it was weak. 7. Group Specific-PCR appeared to be useful in the confirmation of O3:K6 serotype interrelations. 8. Three strains which showed difference of 7 DNA sequence even in the same serotype were detected by the result of analyzing the regular gene, toxRS DNA sequence. These strains are differ from general strains which carry infection easily. 9. These mutual dose epidemiological relations were classified into smaller-parts through PFGE method. As a result of such classify, 3 findings were found. V. parahaemolyticus sampled from diarrhea patients were classified into 3 types. And third, the result obtained through PFGE method can be used as a useful tool in a point of molecular-epidemiological view.

• Korean Journal of Agricultural Science
• /
• v.36 no.1
• /
• pp.1-10
• /
• 2009

The characteristics of fruit ripening and cell wall modifications of two oriental pear fruits were compared during storage. The loss of fresh weight was lower in 'Pingguoli' than 'Niitaka', probably due to the difference in wax accumulation and skin structure. 'Pingguoli' produced much higher amount of ethylene and showed climacteric ripening pattern, but this response was not found in 'Niitaka'. A significant difference in soluble pectin contents was found, thus, the amount of water soluble pectins were much higher in 'Niitaka' at harvest but this difference was not significant at later stage of storage. A severe loss of water soluble pectins in 'Niitaka' was confirmed whereas a similar tendency was not found in CDTA soluble ones. Even the amount of $Na_2CO_3$ soluble pectins was relatively low, 'Pingguoli' contained approximately 2 times higher than 'Niitaka' and both cultivars showed an increasing tendency in $Na_2CO_3$ soluble polymers at later stage of storage. No significant difference in alkali soluble polysaccharides (hemicelluloses fraction) was found between both cultivars. There was a significant change in gel filtration profiles regardless of cultivars, especially in water soluble pectins resulting from severe depolymerization probably due to degradation of higher molecular weight pectins and loss of their side chains. In gel filtration profiles of $Na_2CO_3$ soluble pectins, neutral sugars were evenly distributed regardless of molecular size of pectic polymers but the decrease of high molecular weight fraction was found. In comparison of alkali soluble polymers, a similar trend was found, that is, there was no difference in gel filtration profiles but 'Niitaka' seemed to have longer side chains in alkali soluble polysaccharides in both 4% and 24% of KOH soluble fractions.

• Korean Journal of Environmental Biology
• /
• v.29 no.3
• /
• pp.144-153
• /
• 2011

In this study, samples were collected from the Sumummulbangdui wetland at the Halla Mountain in Jeju Island in order to isolate novel bacterial strain. Bacterial strains belonging to the class Alphaproteobacteria, and Gammaproteobacteria were isolated after spreading samples onto solid agar media. The 16S rRNA gene sequences of the strains assigned to the two classes were compared to those of type strains of the species. The strains that showed less than 98.7% 16S rRNA gene sequence similarity to the validly published species were considered to be novel species candidates. A total of 19 strains were regarded as novel strains which can be regarded as novel species candidates. In the Alphaproteobacteria, 6 novel strains were affiliated with the genera Novosphingobium, and Rhizobium. A total of 13 novel strains belong to Gammaproteobacteria that assigned to the family Moraxellaceae, Pseudomonadaceae, and Enterobacteriaceae were identified. Cultural, physiological, chemotaxonomic characteristics and fatty acids compositions have been determined for the novel species candidates, and the characteristics are described in this study.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.41 no.10
• /
• pp.649-657
• /
• 2017

A rupture in a high-pressure pipe causes the fluid in the pipe to be discharged in the atmosphere at a high speed resulting in a supersonic jet that generates the compressible flow. This supersonic jet may display complicated and unsteady behavior in general. In this study, Computational Fluid Dynamics (CFD) analysis was performed to investigate the compressible flow generated by a supersonic jet ejected from a high-pressure pipe. A Shear Stress Transport (SST) turbulence model was selected to analyze the unsteady nature of the flow, which depends upon the various gases as well as the diameter of the pipe. In the CFD analysis, the basic boundary conditions were assumed to be as follows: pipe of diameter 10 cm, jet pressure ratio of 5, and an inlet gas temperature of 300 K. During the analysis, the behavior of the shockwave generated by a supersonic jet was observed and it was found that the blast wave was generated indirectly. The pressure wave characteristics of hydrogen gas, which possesses the smallest molecular mass, showed the shortest distance to the safety zone. There were no significant difference observed for nitrogen gas, air, and oxygen gas, which have similar molecular mass. In addition, an increase in the diameter of the pipe resulted in the ejected impact caused by the increased flow rate to become larger and the zone of jet influence to extend further.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.44 no.5
• /
• pp.72-79
• /
• 2012

In this study, to understand the aging factor and mechanism in different partitions of the beeswax-treated volumes, the duplicated beeswax-treated volume was artificially aged at $80^{\circ}C$ of temperature and 65% of relative humidity and then a physical and optical properties of an aged volumes was analyzed. Also, the degraded components of the beeswax samples isolated from different partitions of aged volumes was measured using a gas chromatography/mass spectroscopy (GC/MS). In results, the surface of beeswax-treated volume which is primarily affected by a main aging factors such as light, oxygen, moisture was more deteriorated than the inside of that volume. However, unlike inside of the book volume which was made from paper, the inside of beeswax-treated volume wax was also considerably deteriorated. The inside of the beeswax-treated volume is largely unaffected by the oxygen and humidity during aging due to the water repellency and the air permeation resistance of beeswax. Therefore, it is confirmed that aging factors and mechanisms in the inside of the volume are different from thats of the outside of the volume. This fact was also verified by the results of GC/MS analysis of an beeswax samples which was sampled from different partitions of aged volumes. As result as GC/MS analysis of the beeswax extracted from the outside of the aged volume, the low molecular compounds with a carbon length of $C_9-C_{20}$ (fatty acid, etc) were increased and the compounds with a carbon length of above $C_{34}$ (ester, etc) were also increased. But the compounds with a chain length of $C_{21}-C_{36}$ (hydrocarbon, alcohol, etc) were decreased. In case of the aged beeswax of inside, the low molecular compounds with a carbon length of $C_9-C_{20}$ (fatty acid, etc) and the compounds with a chain length of $C_{21}-C_{36}$ (hydrocarbon, alcohol, etc) were increased. While, the compounds with a carbon length of above $C_{34}$ (ester, etc) were decreased.