• The Korean Journal of Food And Nutrition
• /
• v.13 no.5
• /
• pp.446-452
• /
• 2000

This study was designed to observe the body growth and components of edible mugwort(Artemisia sp.) and medicinal mugwort(Kanghwa medicinal mugwort) . Twenty-four young rats of Sprague Dawley strain, body weight of about 89g were used in this study. They were fed on the basal diet(control diet) supplemented with 5% edible mugwort powder ( EM diet) and 5% medicinal mugwort powder( MM diet) for 4 weeks respectively. In proximate composition of nutrients of mugwort in dry basis(100g). crude protein (16.4g) and crude ash(11.8g) contents of EM were higher to about 2% than that of MM, but crude lipid content(4.3g) of EM was lower to about 2% than that of MM. However, the contents in calcium(6.9g) of MM was higher to 5.3 times than that of EM. but in Mn(17mg), Zn(0.5mg), Fe(131mg), Mg(337mg) of EM were higher to 2.8∼2.3 times and vitamin A(39,776 IU) of EM was higher to 2.9 times than that of MM respectively. Body wight gain rate and diet efficiency ratio of EM and MM diet group were similar to that of the control group. The contents of total protein, albumin, urea nitrogen. creatinine, uric acid, total cholesterol, HDL-C, LDL-C, glucose, amylase, transaminase (GOT, GPT) in serum exhibited no remarkable difference among of the EM and MM diet group but the level of LDH activity of MM diet group were significantly lower than that of the control group and EM diet group.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.2
• /
• pp.271-280
• /
• 2010

Vibrio alginolyticus, a Gram-negative marine bacterium, is one of the causative agents of fish vibriosis. Its virulence factors and pathogenesis mechanism are barely known, except for some extracellular products (ECPs) that are known to be regulated by quorum sensing system. Therefore, the present study used a microarray to analyze the transcription profiles of the wild-type V. alginolyticus and a deletion mutant of luxO, the pivotal regulator in Vibrio quorum sensing systems, which resulted in the identification of a putative virulence factor, MviN. Quantitative real-time reverse transcription PCR confirmed that the transcription of mviN was upregulated in the luxO mutant when compared with wild-type, and down regulated in a luxO-con complemented strain. Furthermore, Western blotting indicated that MviN was greatly induced during the late-exponential and stationary phases of growth, indicating that the expression of MviN was cell-density dependent and quorum sensing regulated in V. alginolyticus. Meanwhile, the mviN null mutant displayed a much slower growth rate than the wild type, signifying the essential role of MviN in V. alginolyticus. Western blotting also revealed that MviN was present as an extracellular protein in V. alginolyticus. When epithelioma papulosum cyprini (EPC) cells were treated with the ECPs of the mviN mutant, no cytotoxicity was observed, whereas EPC cells treated with the wild type exhibited pathological changes, which increased with the ECPs concentration and treatment time. Therefore, the results demonstrated that MviN is a LuxO-regulated ECPs component and involved in the pathogenicity of V. alginolyticus.

• Applied Microscopy
• /
• v.25 no.3
• /
• pp.99-107
• /
• 1995

The morphological changes of primary solid particles as a function of process time on hypereutectic Al-15.5wt%Si alloy during semi-solid state processing with a shear rate of $200s^{-1}$ are studied. In this alloy, it was observed that primary Si crystals are fragmented at the early stage of stirring and morphologies of primary Si crystals change from faceted to spherical during isothermal shearing for 60 minutes. To understand the role of Al dissolved in the primary Si crystal by shear stress at high temperature, lattice parameters of the primary Si crystals are determined as a variation of high order Laue zone(HOLZ) line positions measured from convergent beam electron diffraction(CBED) pattern. The lattice parameter of the primary Si crystal in the rheocast Al-15.5wt%Si alloy shows tensile strain of about 5 times greater than that of the gravity casting. Increase of the lattice parameter by rheocasting is due to the increased amount of Al dissolved in the primary Si crystal accelerated by shear stress at high temperature. The amounts of solute Al in the primary Si crystal are measured quantitatively by EPMA method to confirm the CBED analysis.

• Proceedings of the Botanical Society of Korea Conference
• /
• 1999.08a
• /
• pp.55-67
• /
• 1999

A puc -deleted cell of Rhodobacter sphaeroides grows with a doubling time longer than 160 h under the light-limiting photoheterotrophic ( 3 Watts [W]/㎡) conditions due to an absence of the peripheral light-harvesting B800-850 complex. A spontaneous fast-growing mutant, R.sphaeroides SK101 was ioslate dto have∼40-h doubling at 3 Watts/㎡, while the growth of the mutant was not distinguished from its parental strain during both aerobic and light-saturating photoheterotrphic (10W/㎡) growth. The B875 complex of SK101 under the light-limiting conditions was elevated by 20 to 30% compared with that of the puc -deleted cell, reflecting parallel increase of bacteriochlorophyll and carotenoid contents of the mutant. The formation of B875 complex of SK101 under the anaerobic dark conditions with dimethylsulfoxide was the same as that of the puc-deleted cell. suggesting that the mutation of SK101 result in the altered control of B875 complex formation by light. When puc is restored in SK101 , it is not B875 complex but B800-850 complex which formation is elevated. The mutation of SK101 affected the bchF transcription most drastically to show two to tenfold increase during both aerobic and photoheterotrophic growth. The mutated phenotype of SK101 was complemented with pW2, which contains approximately 100-kb HNA of the photosynthetic gene clusters. The complementing DNA was narrowed down to a 1.1-kb DNA containing orfQ and pufKBA . The mutation of SK101 appeared to be exerted through the mutation of the orfQ gene encoding a putative bacteriochlorophyll -mobilizing protein.

• Korean Journal of Veterinary Service
• /
• v.33 no.1
• /
• pp.13-21
• /
• 2010

Chicken anemia virus (CAV) has been recognized as an immunosuppressive agent and plays role as an etiological agent of multifactorial diseases in chicken. In this study, we investigated distribution of CAV antibody by ELISA and the virus gene by PCR in poultry farms in Jeongeup, Jeonbuk province. In the test using ELISA kit, 41 (95.3%) of 43 flocks and 88.6% of the individual chickens were positive, respectively. By PCR, 90.9% of the broiler breeders and 75.0% of White-semi breeders were found positive, respectively. All hatchery was negative by PCR. Of the clinical cases from 49 poultry flocks, 87.5% of flocks and 54.7% for each samples were found positive by ELISA, respectively. By PCR test, 21 (42.9%) of 49 flocks were positive. Major clinical signs of the infected flocks were growth retardation, femoral subcutaneous bleeding, depression, limping, and continuing selection. The genetic analysis of separate N genes of CAV showed highly homologous each other. The nucleotide sequence of field isolates had homology ranged from 99.9% to 97.5% with Chinese strains, and 99.9% to 99.6% with Japanese strain. Phylogenetic analysis based on the N gene of CAV isolates showed the closely relation with Chinese strains. The results of this survey could be used as basic data for development of vaccine.

• Food Science of Animal Resources
• /
• v.40 no.5
• /
• pp.758-771
• /
• 2020

This study was to investigate the prevalence and characteristics of antimicrobial-resistant Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) from 4,264 retail meat samples including beef, pork, and chicken in Korea between 2013 and 2018. A broth microdilution antimicrobial susceptibility testing was performed for S. aureus. Molecular typing by multilocus sequence typing (MLST), spa typing, and pulsed-field gel electrophoresis (PFGE), was performed on mecA-positive S. aureus strain. S. aureus was isolated at a rate of 18.2% (777/4,264), of which MRSA comprised 0.7% (29 strains). MLST analysis showed that 11 out of the 29 MRSA isolates were predominantly sequence type (ST) 398 (37.9%). In addition, ST72, ST692, ST188, ST9, and ST630 were identified in the MRSA isolates. The spa typing results were classified into 11 types and showed a high correlation with MLST. The antimicrobial resistance assays revealed that MRSA showed 100% resistance to cefoxitin and penicillin. In addition, resistance to tetracycline (62.1%), clindamycin (55.2%), and erythromycin (55.2%) was relatively high; 27 of the 29 MRSA isolates exhibited multidrug resistance. PFGE analysis of the 18 strains excluding the 11 ST398 strains exhibited a maximum of 100% homology and a minimum of 64.0% homology. Among these, three pairs of isolates showed 100% homology in PFGE; these results were consistent with the MLST and spa typing results. Identification of MRSA at the final consumption stage has potential risks, suggesting that continuous monitoring of retail meat products is required.

• Journal of Electrochemical Science and Technology
• /
• v.12 no.4
• /
• pp.431-439
• /
• 2021

This research work aims to investigate the effect of the aerobic bacterium, Pseudomonas aeruginosa on the mechanical and electrochemical properties of the 316L stainless steel and α-brass. These properties of both the alloys were determined after 7 days of exposure to the controlled and inoculated media at 37℃. The microstructural and electrochemical test results revealed the deleterious effects of Pseudomonas aeruginosa. After exposure to the inoculated medium, the scanning electron microscopy (SEM) results showed the larger pitting and formation of relatively dense biofilm on α-brass compared to 316L stainless steel. The tensile strength and hardness of 316L stainless steel were slightly affected after exposure to the controlled and inoculated media. After exposure to the controlled medium and inoculated media, the tensile strength of the α-brass was least affected but a significant decrease in the hardness (from 165 HV to 124 HV) was observed due to the severe attack induced by the Pseudomonas aeruginosa. Similarly, the open-circuit potential of the 316L stainless steel in the inoculated medium was measured to be less active (-410 mV vs Ag/AgCl) than α-brass (-550 mV vs Ag/AgCl). In the inoculated medium, potentiodynamic polarization curves confirmed the severe attack of Pseudomonas aeruginosa on α-brass (7.15 × 10^-2 mm/year) compared to 316L stainless steel which registered a corrosion rate of 5.14 × 10^-4 mm/year.

• Applied Chemistry for Engineering
• /
• v.9 no.6
• /
• pp.935-941
• /
• 1998

New type of chitosan deriertives was synthesised by graft copolymerization of mono(2-methacryloyl oxyethyl) acid phosphate into chitosan. The reaction conditions showing the highest percentage of grafting were an initiator concentration of $3.5{\times}10^{-3}M$, monomer concentration of 0.19 M, and reaction temperature of $40^{\circ}C$, while rate of grafting showed same value after elapsing 4hours of reaction time. The antifungal activity of chitosan depending on content of free amine and kind of monomer was examined against Candida albicans, Trichophyton rubrum and Trichophyton uiolaceum by shake flask method. The pH value of buffer solution to show the highest antifungal activity was 5.75, and the selectivity of mold strain was observed.

• Journal of Microbiology and Biotechnology
• /
• v.7 no.4
• /
• pp.215-222
• /
• 1997

The regulatory mechanism of the flux of acetyl-CoA in Alcaligenes eutrophus in unbalanced growth conditions was investigated using a PHB-negative mutant and transformants reintroduced PHB-biosynthesis enzymes through the transformation of cloned phbCAB genes. The PHB-negative mutant was defected absolutly in PHB synthase but partially in ${\beta}$-ketothiolase and acetoacetyl-CoA reductase, and excreted substantial amount of pyruvate to culture broth at late growth phase. The excretion was due to the inhibitory effect of acetyl-CoA on the activity of pyruvate dehydrogenase. The cloned phbC and phbCAB genes were transformed to the PHB-negative mutant strain to reintroduce PHB biosythesis enzymes. Pyruvate excretion could be decreased substantially but not completely by transformation of PHB synthase alone, while pyruvate excretion was ceased by transformation of all three PHB biosynthesis enzymes. To identify the most critical PHB biosynthesis enzyme influencing on the flux of acetyl-CoA, the effect of the variation of PHB biosynthesis enzymes on pyruvate dehydrogenase was investigated. ${\beta}$-Ketothiolase influenced the activity of pyruvate dehydrogenase more sensitively than PHB synthase. ${\beta}$-Ketothiolase, the first step enzyme of PHB biosynthesis that condense acetyl-CoA to acetoacetyl-CoA, seems to be the major enzyme determining the flux of acetyl-CoA to PHB biosynthesis or TCA cycle, and the rate of PHB biosynthesis in A. eutrophus.

• Computers and Concrete
• /
• v.17 no.1
• /
• pp.1-27
• /
• 2016

Final construction project cost is significantly determined by construction rate. The Industrialized Building System (IBS) was promoted to enhance the importance of prefabrication technology rather than conventional methods in construction. Ensuring the stability of a building constructed by using IBS is a challenging issue. Accordingly, the connections in a prefabricated building have a basic, natural, and essential role in providing the best continuity among the members of the building. Deficiencies of conventional precast connections were observed when precast buildings experience a large induced load, such as earthquakes and other disasters. Thus, researchers aim to determine the behavior of precast concrete structure with a specific type of connection. To clarify this problem, this study investigates the capacity behavior of precast concrete panel connections for industrial buildings with a new type of precast wall-to-wall connection (i.e., U-shaped steel channel connection). This capacity behavior is compared with the capacity behavior of precast concrete panel connections for industrial buildings that used a common approach (i.e., loop connection), which is subjected to monotonic loading as in-plane and out-of-plane loading by developing a finite element model. The principal stress distribution, deformation of concrete panels and welded wire mesh (BRC) reinforcements, plastic strain trend in the concrete panels and connections, and crack propagations are investigated for the aforementioned connection. Pushover analysis revealed that loop connections have significant defects in terms of strength for in-plane and out-of-plane loads at three translational degrees of freedom compared with the U-shaped steel channel connection.