• Microbiology and Biotechnology Letters
• /
• v.26 no.4
• /
• pp.275-282
• /
• 1998

To investigate the increased acid tolerance of a acid-resistant mutant Leuconostoc paramesenteroides P-100 improved as a kimchi starter, proton permeability, ATPase acitivity, glycolysis activity, $Mg^2$sup +/ releasement, and membrane fatty acid composition were studied and comprised with its wild type Leuconostoc paramesenteroides Pw. In the proton permeability experiment, the maximum values of the average half time (t$\_$1/2/) of pH equilibration through the cell membrane of the Pw and the P-100 were about 6.4 min and 7.8 min in 150 mM KCI solution, respectively. In the 3% NaCl solution, the t$\_$1/2/ values of the Pw and the P-100 were 5.5 min and 6.9 min, respectively. The values and pHs of maximal specific activities of ATPase originated from the Pw and the P-100 were 0.5 unit/mg protein and 0.78 unit/mg protein at pH 6.0, respectively. The result of pH dependence of glycolysis showed that the P-100 had higher activities than that of Pw except at pH 7.0. The releases of magnesium from the Pw and the P-100 were observed about 54.5% and 23.2% at pH 4.0 after 2 hours, respectively. The results of comparison of membrane fatty acid composition of the Pw with the P-100 showed that C$\_$8:0/, C$\_$9:0/, C$\_$10:0/, C$\_$11:0/, C$\_$18:0/, and C$\_$19:0,cyclo/ were major different fatty acids between two strains and the content of C$\_$18:1/, and C$\_$19:0,cyclo/ were 2.8%, N.D (not detected) in the Pw and 0.4%, 2.3% in the P-100. These results indicated that acid tolerance of the P-100 was significantly improved in comparison with its wild type Pw.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.31 no.5
• /
• pp.767-773
• /
• 1998

In this study, we have investigated the distributions and killing effects of marine bacteria that tend to kill the red tide microalgae, C. polykikoides in the area of Masan bay from June to October, 1996. To summarize, C. polykikoides killing bacteria were detected at $10^2$ to $10^3$ cells/ml of seawater samples during the survey period, and the bloom was observed in September by containing $4.8\times10^3$cells/ml. It appears however that the number of these bacteria is decreased ($2.0\times10^2$cells/ml) in October, A total of 110 strains were isolated from seawater samples and seawater filtrate (pore size, 0.8 $\mu$m)-containing mixed culture of C. polykikoides in which the mixed culture was grown in f/2 medium. As results we have successfully isolated Micrococcus sp. LG-1 which decreased to less than 10cells/ml within 6days and 5days sfter inoculation of Micrococcus sp. LG-1 into the la9 and logarithmic growth phases of C. polykrikoides respectively. Therefore, it appears that inoculation of Micrococcus sp. LG-1 against the logarithmic C. polykrikoides is more effective than the lag growth phase, (n addition, the killing effects were increased in accordance with bacterial cell densities inoculated in a dose dependent manner. Especially, the filtrate of kitling bacterium culture (nore size, 0.2 $\mu$m) revealed a dramatic effect in which C. polykrikoides were decreased to less than 10 cells/mf of culture within 1 hr, 1,5 hrs, 1,5 hrs, 3.5 hrs. and 5,5 hrs after inoculations of the culture filtrate with concentration of $30\%,\;20\%,\;10\%,\;5\%$ and $2.5\%$, respectively. Moreover Micrococcus sp. LG-1 showed a selective specificity against C. polykrikoides and any other killing effects of Micrococcus sp. LG-1 were not observed against Alexandrium tamarense, Prorocentrum micans, Scrippsiella trochoidea. ana Gymnodinium sanguineum.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.2
• /
• pp.121-126
• /
• 1999

In order to degrade chitin by enzymatic hydrolysis, it is required from screening highly active deacetylase. To this end, we examined three fungal strains and it turned out that Mucor rouxii produced highly active deacetylase, this enzyme exhibited the highest enzymatic activity against colloidal chitin. The conditions for growing Mucor rouxii are as follows; the effective carbon source, nitrogen source, adequate initial pH, temperature and incubation time were $2\%$ glucose, $1.33\%$ yeast extract, $0.66\%$ pepton, 4.5, $25{\pm}2^{\circ}C$ and 48hr, respectively. The optimum pH and temperature for purified enzyme activity were 5.5 and $40^{\circ}C$, respectively. The purified enzyme was stable at pH ranging from 4.5 to 5.5. However, the enzyme activity was decreased to less than $50\%$ at pH blow 45 and above 7.5. At temperatures above $50^{\circ}C$, the enzyme activity was decreased remarkably. The enzyme was inhibited by LiC1, $HgCl_2$, and $BaCl_2$, but stimulated by $CaCl_2$ and $ZnC1_2$, The activity of purified enzyme was increased by L-cysteine and 2-mercaptoethanol, while decreased by O-phenanthroline, p-CMB, EDTA, and iodoacetate. The $K_m$ and the $V_{max}$ value of purified enzyme were $1.2\%$ and 59.5 U/mg, respectively. The deacetylation activity of purified enzyme was not detected at optimal reaction condition when chitin particle suspension was used.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.34 no.6
• /
• pp.611-616
• /
• 2001

The bacteriological and physiochemical analysis of seawater in Tongyeong harbor was conducted to evaluate sanitary conditions, The samples were collected at 6 stations established once a month from January to December, 2000. During the study period, the ranges of temperature, transparency, chemical oxygen demand, dissolved oxygen, dissolved nitrogen, phosphate and chlorophyll-a were $6.8\sim25.2^{\circ}C,\;1.0\sim2.5\;m,\;1.79\sim2.41\;mg/L,\;5.7\sim10.1\;mg/L,\;6.59\sim10.53{\mu}g-at/L,\;0.56\sim1.01{\mu}g-at/L\;and\;1.21\sim9.54\;mg/m^3$, respectively, The viable cell counts of seawater in Tongyeong harbor ranged from $3.0\times10^4CFU/mL\;to\;6.9\times10^6CFU/mL$. The coliform group and fecal coliform MPN's of the samples were ranged $23\~4,600\;MPN/100\;mL$ (means 540 MPN/100 mL) and $11\~1,600\;MPN/100\;mL$ (means 210 MPN/100 mL), respectively, The coliform group was classified with IMViC reactions and pathogenic vibrios were analyzed. Two hundred eighteen strains that were obtained from seawater samples in Tongyeong harbor represented Escherichia coli group, $66.1\%$; Citrobacter freundii group, $11.0\%$; Enterobacter aerogenes, $9.6\%$; and unknown, $13.3\%$, respectively. During the study period, infectious bacteria such as Vibrio cholerae O1, Salmonella sp. and Shigella sp. were not detected from the samples, but detection ratios of V. parahaemolyticus, V cholerae non-O1 and V. vulnificus were $10.0\sim30.1\%$.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.2
• /
• pp.115-121
• /
• 2002

To develop a new method of conjugation and to determine the distribution of R plasimds, we isolated multi-drug resistant strains from fish pathogenic bacteria in the farms of south and east seacoasts of Korea. Out of the 134 isolates examined, 10 showed resistance to chloramphenicol, tetracycline, streptomycin, ampicillin, colistin, nalidixic acid, oxolinic acid and kanamycin. One out of 10 multi-drug resistance bacteria, Vibfio damsela JE1 (V. damsela JE1), contained transferable R plasmid of chlorarnphenicol- tetracycline resistance genes and other nucleic acids encoding ampicillin and kanamycin resistance. The presence of the R plasmid was confirmed by conjugation using the chromocult medium (CC) as a selective and differential medium for transconiugants with identification based on the growth or colors of the colonies. The frequency of R plasmid transfer with filter mating method was come out much higher than that of broth mating method and appeared to be dependent upon the mating time and temperature. The optimum conditions for filter mating method were found to be 30$^{\circ}C$ and 24hrs as mating temperature and period, respectively, Moreover, donor cells with R plasmid, both isolate and standard bacteria, were shown to have an ability to transfer the plasmid against Escherichia coli K-12 HB101 (E. coli HB101) and Edwardsiella tarda (E. tarda) RE14 at fairly high frequencies, finally, we isolated 3 isolates of Sphingomonas sp., carrying R plasmid from 12 multi-drug resistant bacteria in normal microflora of the flounder (Paralichthys olivaceus) group used for the isolation of V emsela JE1 four months before. The same size and gene transfer chayateristics of R plasimds with those of V damsela JE1 confirmed that normal microflora have the reservoir activity for R plasmid in natural aquatic environment.

• Korean Journal of Food Science and Technology
• /
• v.27 no.4
• /
• pp.555-563
• /
• 1995

This study was performed to investigate the effect of Aloe arborescens on the cadmium toxicity in rats. Thirty male Sprague-Dawley strains were divided into five groups consisting of a control group, a cadmium treatment group and 3 aloe(0.5%, 0.75%, 1%) treatment groups and observed for 9 weeks. The weight increment of the cadmium and 0.75% aloe group was higher than that of the cadmium treatment group(p<0.01). The food intake did not show the consistency rule among the experimental groups and the decrement tendency of food intake affected by cadmium feeding group. The decrement tendency of water intake affected by cadmium appeared to be suppressed by aloe treatment, especially cadmium and 0.75% aloe treatment group showed the remarkable increment of water intake. The diet efficiency of the control group was the highest among the experimental groups and that of cadmium and 0.75% aloe group was higher than other aloe treatment groups. The weight of each organ did not show consistency among the experimental groups but only the testicle of cadmium and 0.75% aloe treatment group was heavier than that of the control group. The cadmium accumulation was high in order of kidney>liver>spleen>heart>lung>testicle>brain. The cadmium content of the cadmium treatment group was more than that of cadmium and 0.5% aloe group, cadmium and 0.75% aloe group, cadmium and 1% aloe group. The cadmium content of cadmium and 0.75% aloe group was the lowest among other aloe treatment groups. Therefore, cadmium and 0.75% aloe is the most recommendable aloe treatment to eliminate the cadmium accumulated in organ.

• Journal of the Korean Geophysical Society
• /
• v.3 no.2
• /
• pp.99-112
• /
• 2000

The Iksan Jurassic Granite shows relatively less fractures and homogeneous rock fabrics, and is one of the most popular stone materials for architectures and sculptures. Almost mutually perpendicular rift, grain, and halfway in the Iksan Jurassic Granite are well known to quarrymen based on its splitting directions, and therefore it should exhibit orthorhombic symmetry. Theoretically, there are 9 independent elastic stiffness coefficients $(C_{1111},\;C_{2222},\;C_{3333},\;C_{2323},\;C_{1313},\;C_{1212},\;C_{1122},\;C_{2233},\;and\;C_{1133})$ for orthorhombic anisotropy. In order to characterize the static and dynamic elastic properties of the Iksan Jurassic Granite, triaxial strains under uniaxial compressive stresses and ultrasonic velocities of elastic waves in three different polarizations are measured. Both experiments are carried out with six directional core samples from massive rock body. Using the results of experiments and the densities measured independently, the static and dynamic elastic coefficients are computed by simple mathematical manipulation derived from the governing equations for general anisotropic media. The static elastic coefficients increase ar uniaxial compressive stress rises. Among those, the static elastic coefficients at uniaxial compressive stress of a 24.5 MPa appear to be similar to the dynamic elastic coefficients under ambient condition. Although some deviations are observed, the preferred orientations of microcracks appear to be parallel or subparallel to the rift, the grain, and the hardway from microscopic observation of thin sections. This indicates that the preferred orientations of microcracks cause the elastic anisotropy of the Iksan Jurassic Granite. The results are to be applied to the effective use of the Iksan Jurassic Granite as stone materials, and can be used for the non-destructive safety test.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.3
• /
• pp.267-273
• /
• 2009

Antioxidative, antimicrobial activities and Raw 264.7 cell viability as cytotoxicity of various solvent extracts from leaf of Eriobotrya japonica Lindl. dried by different methods were investigated for processing as functional ingredient. In DPPH radical scavenging activity, RLE (80% EtOH extract of raw leaf) and FLE (80% EtOH extract of freeze-dried leaf) exhibited strong scavenging effect on $300{\mu}M$ DPPH radical solution (1.71 mg/mL and 2.11 mg/mL for RLE $SC_{50}$ and FLE $SC_{50}$). Also in nitric oxide scavenging activity, RLE and FLE showed strong activities (83.9% and 82.2% in 5 mg/mL sample concentration). Total phenolic compound contents of each extracts were found to be $73.7{\sim}215.4$ mg/g and RLE was showed the highest phenolic compound content. Also, total flavonoid contents were found to be $24.85{\sim}110.3$ mg/g and RLE was showed the highest flavonoid content. In antimicrobial activity, RLE was showed higher growth inhibition effect against all microbial strains. RLE, RLW (hot water extract of raw leaf), and FLW (hot water extract of freeze-dried leaf) exhibited strong antimicrobial activities against MRSA and S. aureus. In measurement of cytotoxicity by MTT assay, Raw 264.7 cell viabilities of 80% EtOH extracts showed better effect than water extracts. Especially viability of RLE was found be over 100% in every tested sample concentration.

• Tuberculosis and Respiratory Diseases
• /
• v.43 no.6
• /
• pp.852-861
• /
• 1996

Background : Many clinicians have experienced the difficulty of decision on termination of antituberculosis chemotherapy after the 6th month due to relapse of disease. There is still controversy in the effect of 2S(K)HRZ/4HRZ 6-month short course chemotherapy including pyrazinamide for 6 months in patiems with pulmonary tuberculosis. And there is no long term follow-up study of 6-month short course chemotherapy for pulmonary tuberculosis in korea. So we had performed the study to find the result of 6-month antituberculosis chemotherapy for 4 years. Method : We studied prospectively the effect of 2S(K)HRZ/4HRZ in one hundred-fifty patients with pulmonary tuberculosis and followed up fifty-nine patients for more than 1 year to 4 years after the completion of 6-month short course therapy. Results : 1) Out of one hundred-fifty patients, seventy-two patients(48%) completed the prescribed 6-month chemotherapy. Sixty-eight patients(45.3%) have experienced premature discontinuation and the most common cause of premature discontinuation was drop-out against advice(thirty-six patients, 24%). Ten patients(6.7%) were treated beyond the 6 months mainly due to irregular treatment. 2) Fifty-nine patients(81.9%) among seventy-two patients with completed treatment have been followed up for more than 1 year and 32 patients(44.4%) for more than 4 years. There was three relapse patients of whom two patients have experienced relapse of pulmonary tuberculosis within 1 year after the termination of chemotherapy. 3) Among one hundred-thirty-four patients who have been assessible for more than two months of chemotherapy, including the patients who experienced within 2 months, there were eighty-two patients(61.2%) who have experienced adverse reactions and the treatment regimen was changed only in thirteen patients(9.7%). The most frequent cause of adverse reactions was arthralgia and/or hyperuricemia, which had occurred in 33 patients(24.6%). Conclusion : In a university hospital in Korea, 6-month shot course chemotherapy of 2S(K)HRZ/4HRZ had unnegligible relapses and premature discontinuation. Therefore, change of the regimen might be carefully considered by drug susceptibility results. Close monitoring of patients, retrial of sputum exam and radiologic evaluation during treatment might be required in the endemic area of drug resistant strains like in Korea. Further study about the effect of 6-month short course chemotherapy including pyrazinamide for 6-month might be needed.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.8
• /
• pp.1157-1163
• /
• 2011

This study was conducted to investigate the cause of microbiological contaminants in aseptic chocolate milk and evaluate the effect of a physicochemical treatment on the growth inhibition of isolated bacterial strains. The bacterium isolated from aseptic chocolate milk was identified as Bacillus lentus and was named B. lentus M1. In the heat and pH treatment, the growth of B. lentus was inhibited at 110$^{\circ}C$ for >15 min and at pH's <5 and >10. An electrolyzed water treatment against B. lentus M1, revealed 5 mm growth past the inhibition zone. The effect of ozone gas on B. lentus M1 growth was evaluated using viable cell counts. When the initial number of B. lentus M1 was $10^2$ and $10^3$ CFU, the bacteria were completely suppressed by ozone gas treatment for 10 and 30 min, respectively. In a microwave treatment, B. lentus M1 was sterilized following microwave treatment for 1 min. As the result of ${\gamma}$-irradiation against B. lentus M1, numbers decreased as the ${\gamma}$-irradiation dosage increased. These results show the growth inhibition effects against contaminants in aseptic chocolate milk using physicochemical treatments.