• Journal of Microbiology
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• 제40권4호
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• pp.340-343
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• 2002

A PCB degrader, Ralstonia eutropha H850 was shown to induce bphC gene encoding 2,3-dihydroxy-biphenyl-1,2-dioxygenase in a carvone-amended pure culture in our previous study (Park et al.,1999). The present study was carried out to examine how plant terpenes, as natural substrates, would cause an expression of a PCB degradative gene in soil that was amended with terpenes. The population of Ralstonia eutropha H850 was maintained at least around 10$\^$8/ (CFU/g fresh soil) in the soil amended with carvone or limonene in the presence of succinate as a growth substrate at 50 th day. The gene expression was monitored by RT-PCR using total RNA directly extracted from each soil and bphC gene primers. The bphC gene expression of the seeded strain H850 was observed in the soil amended with biphenyl (4 days) but not with succinate, carvone and limonene. These results indicate that terpenes widely distributed in nature could be a potential inducing substrate for effective PCB biodegration in the soil but their bioavailability and specific induction behavior should be taken into account before PCB bioremediation implementation.

• 미생물학회지
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• 제27권3호
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• pp.265-271
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• 1989

서해안의 대표적 내만인 천수만 해역에서 4계절간 분리한 세균들을 대상으로 수리학적 분류를 설시하였다. 총 48가지의 형태학적, 생리적, 생화학적 실험 결과 분리된 계절에 따라 온도에 대한 서로 다른 적응 양상을 보여 주었으며, 전체적으로 다양한 환경변화에 높은 생존 능력을 보여주였다. 각 세균을 동정한 결과 Enterobacteriaceae, Aeromonas Pseudomonas와 Vibrio 등이 우점종으로 나타났으며, 계절별로는 봄 가을에 Aeromonas가, 여름 및 겨울에는 각각 Pseudom monas 와 Enterobacteriaceae가 제l우점종임이 발견되었다 Cluster analysis 결과 젠체 세규 군집은 75%의 유사도 수1 에서 총 29개의 phenetic group으로 나뉘어졌으며 각 group별로 계절적 구분이 뚜렷하였다. 전체적으로 계절에 놔른 서로 다른 생리적 특성과 종 구성이 전반적인 생태계에의 다양성과 안정성을 높여주는 것으로 나타났다.

• 미생물학회지
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• 제27권3호
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• pp.291-296
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• 1989

Campylobacter jejuni was studied for its disinfection by heat-and cold-treatment and UV-irradiation. When C. jejuni was treated by heat, no viable cell was found after 10 min treatment at $55^{\circ}C$, whereas small fraction of cell population was survived after 60 min treatment at $45^{\circ}C$ and $50^{\circ}C$. When they were treated by cold temperature for 30 days, no cell was survived at -$23^{\circ}C$ but about 4 log of the cells were survived at both temperature of $4^{\circ}C$ and -$40^{\circ}C$. When the organisms were UV-irradiated, thier survival rates were proportionally varied to the distance of irradiation. The scanning electron microscopic studies of C. jejuni cells treated by the disinfecting agents revealed that shapes of thecells were deformed from spiral rod into spherical form. The heat-treated cells showed rough and damaged surface on the scanning electron micrographs. In the heat-treated cells, some proteins of high molecular weight appeared to become accumulated in the electrophoretic analysis. The DNAs extracted from the cells treated with the physical agents showed some differences in agarose gel electrophoresis, comparing those of normal cells.

• 미생물학회지
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• 제29권2호
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• pp.136-142
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• 1991

The selection of ethanol-tolerant strains was applied to enrichment culture of YPD broth medium containing various concentrations of ethanol. Isolates were identified to be Saccharomyces cerevisiae, the others as S. dairensis, S. exiguus, S. telluris, Saccharomycodes ludwigii, Schwanniomyces occidentalis var. occidentalis and Zygosaccharomyces florentinus. Among isolates S. cerevisiae YO-1 was screened as having the highest ethanol tolerance and produced 18% (v/v) ethanol after 4 days fermentation. The change of fatty-acyl residues represents that a progressive decrease in fatty-acyl unsaturation and a proportional increase in saturation in phospholipids of yeast cells during fermentation affected the yeast viability. Supplementation ethanol to the cultures led to an increase of unsaturated fatty-acyl residues, especially $C_{16}$ or $C_{18}$ residues, along with a decrease in the proportion of saturated residues in cellular phospholipids. Increasing the amount of soy flour led to an increase in the maximum number of viable yeast cells and ethanol production. It was possible in 4 days to reach 21% (v/v) ethanol by adding 4% soy flour as source of unsaturated fatty-acyl residues to the fermentation medium. Soy flour not only increased yeast population but also enhanced the physiological properties of yeast cells to be ethanol tolerant in the anaerobic culture.

• 미생물학회지
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• 제30권3호
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• pp.187-192
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• 1992

서해 경기만의 6개 정점을 대상으로 1990년 3월부터 1991년 10월까지 총 8외에 걸처 석유 분해세균의 공간적, 시간적 분포를 조사하였다. 또한, 서로 다른 배양 조건하에서의 해양 세균 군집의 석유 뷴해능도 연구하였다. 연구 기간 중, 종속 영양세균수와 석유분해세균수는 각각 7,000-108,000 CFU/ml, 0-2, 800 MPN/100 ml 로 측정되었다. 석유분해세균의 공간적 분포는 석유 탄화수소의 존제에 의하여 심하게 영향을 받은 것으로 나타났다. 실혐실내 실험에서, 석유 분해는 배양액에 yeast extract, cell free extract 의 첨가 그리고 석유뷴해세균의 접종에 의하여 증진되었다.

• 미생물학회지
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• 제12권2호
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• pp.59-68
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• 1974

With an aim to disclose causal factors scably grains intoxications, the screening of toxic Fusaria and the detection of toxic priniciples were performed in respect of cultured cells bioassay with HeLa cells, skin-necrotizing effect, histopathological investigation and also chromatographic analysis sith following results ; 1. Among the fungi, Fusarium sp. F-27, F-63 and F-61 were highly toxic to mice, causing liver injury characterized necrosis and inflammation. 2. HeLa cell culture bioassay demonstrated that the cell of the isolated strains of Fusaria were suspected to produce toxic material (Fusarenon-X). 3. The culture filtrates of Fusarium nivale Fn-2B, F-27, and F-63, were injected subcutaneously, and caused inflammation followed by crust on the skin ICR-mice. 4. The observation method of skin-necrotizing effect to the mice can be used to the screening to the toxin-producing fungi isolated from many fusarial contaminations.

• 미생물학회지
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• 제22권3호
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• pp.157-165
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• 1984

Seasonal and spatial variations in propagule numbers of Trichoderma species were investigated every other month for one year in deciduous and coniferous forest soils and evaluated the relationships of Trichoderma spp. populations to soil environmental factors. The total population of Trichoderma spp. increased until summer and then declined until winter. The yearly mean frequency of Trichoderma spp. exceeded 1.4% of total fungal propagules in two sites. Decreases of absolute an relative propagule numbers of Trichoderma spp. with increasing soil depth were found and variation in Trichoderma spp. propagules caused by differences in soil depth ($0{\sim}50cm$) was greater than that caused by differences in sampling time. The most common species occurring in two sites was T. viride, followed by T. polysporum, T. koningii, and T. hamatum. Individual species of Trichoderma showed diferent abundance trend in accordance with sampling time. T. viride was dorminant from spring to autumn, while T. polysporum dominated over the other speicies in winter. Variations in propagule number of Trichoderma sppp. were principally mediated by the actions of biotic environmental factors rather than by the direct effects of abiotic factors. In multiple-regression analyses, 48% of the total vaiation in Trichoderma spp. propagules in deciduous site could be accounted for by total fungal propagules and soil CMCase actvity. In coniferous site, 65% of total variation could be accounted for by total fungal and bacterial propagules, moisture content and organic carbon content.

• 미생물학회지
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• 제29권6호
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• pp.402-407
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• 1991

As a baseline survey to clarify the structure and function of bacterial populations in the intertidal waters of the Yellow Sea near Kunsan in 1987/1988, annual variation of bacterial number and biovolume was estimated by AODC method. Rod-shaped bacteria were more than 74% of all cells during the investigation period. Average biovolume of sampled bacteria ranged from ${3.19}\pm0.59*10^{-2}$ to $6.19\pm0.76*10^{-2}$ .$\mu$$m^{3}$ for coccoid bacteria, and from 4.57.+-.0. $17*10^{-2}$ to $12.94\pm0.21*10^{-2}$ .$\mu$$m^{3}$ for rod-shaped ones. It showed that larger biovolume occurred at surface in case of coccoid bacteria, while at bottom in case of rod-shaped ones. There was little correlation between population density and biovolume. Diameters of edlls were below 0.5$\mu$m among 77-89% of all measured coccoid bacteria, and lengthes of cells more than 70% of all measured rod-shaped ones were below $1\mu$m. It explains the high percentage of "mini-bacteria" was distributed in the investigation area.tion area.

• 미생물학회지
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• 제22권3호
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• pp.151-156
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• 1984

When enterobacterium, Escherichia coli B was cultivated with normal media in the presence of $0.2{\sim}0.6%$ Palmitoylcarnitine and $0.05{\sim}0.2%$ Ginseng Saponin, maximum population growth of the bacteria was presented 71% and 31%, respectively. Such a result, in vitro test, was concluded from the result that both detergents stimulated $C^{14}$-glucose, $C^{14}$-alanine and $C^{14}$-phosphatidylethanolamine uptake into the membrane of cells. The pre-treatment of cells with different amounts of Palmitoylcarnitine from $0.005{\sim}0.05{\mu}$ moles represented a significant increase of uptake, 33% of $C^{14}$-glucose, 129% of $C^{14}$-alanine and 158% of phosphatidylethanolamine at the concentration of $0.05{\mu}$ moles of Palmitoylcarnitine. On the other hand, the result of $C^{-2}%$ Saponin treatment showed the maximum value of uptake, 17% of $C^{14}$-glucose and 112% of $C^{14}$-alanine. In case of $C^{14}$-phosphatidylethanolamine, the maximum uptake showed 25% of increase at the concentration of $C^{14}$% Saponin.

• 미생물학회지
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• 제11권3호
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• pp.121-128
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• 1973

In order to clarify the best cultural conditions of Rhizopus niveus the effects of aeration, pH and various nutrients, such as different carbon and nitrogen sources, vitamins, and growth substances, on the mycelial growth were studied through liquid culture, and amylase activities of the fungus at different cultural periods were measured. Soluble starch, xylose and galactose are excellent sources of carbon for growth of the fungus. Sorbose and lactose are utilized slightly for growth. peptone, ammonium sulfate and alanine are excellent nitrogen sources for growth, tyrptophane nad potassium nitrate are utilized slightly for growth and sodium nitrite is not utilized. Thiamine nad gibberellin are excellent growth substances for the fungal growth, and biotin, nicotinamide and indole acetic acid (IAA) are also effective. Rhizopus niveus grows better at rotatory culture than at stationary culture and earlier growth of the fungus increases remarkably at rotatory culture. Optimum pH than at pH3. Growth increases linerly with an increase of soluble starch content up to 100g per liter medium, but 5 grams of ammonium sulfate per liter is the optimum nitrogen concentration for growth, if Pfeffer's medium is employed. Amylase activities of Rhizopus at different cultural periods showed that the maximum amylase production takes place after the cell population has reached its peak in the culture. Dextrinogenic amylase production has reached maximum at stationary phase, and maximum saccharogenic maylase production takes place in the pahse of negative gorwth acceleration.