• Preventive Nutrition and Food Science
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• 제9권4호
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• pp.312-316
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• 2004

Sterilized raw ground pork was inoculated with Pseudomonas aeruginosa (PA) and Lactobacillus casei (LC) to investigate the relationship between microbial growth and 2-thiobarbituric acid reactive substances (TBARS) values. The analyses including microbial growth, pH, and TBARS values were performed during 3 weeks of storage at room temperature $(20^{\circ}C)$. The radiation-sterilized control sample did not show any microbial growth, but the samples inoculated at different levels (diluted twice vs non-diluted) exhibited differences until 1 week. However, the difference disappeared at weeks 2 and 3. The pH of raw ground pork inoculated with PA increased, but that of LC decreased. The pH of non-inoculated samples increased slightly after storage. The TBARS values in non-inoculated and LC inoculated with pork increased, but TBARS remained unchanged in samples inoculated with PA after 1 week. Results indicated that the microbial growth level and strains can influence the TBARS value of raw ground pork. Thus, it is important to use samples exposed to the same microbial conditions to compare the oxidation of lipids in meat samples.

• 한국식품과학회지
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• 제26권5호
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• pp.644-648
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• 1994

Staphylococcus aureus에 대한 젖산균과 그 대사산물의 항균효과와 그 항균물질의 특성을 조사하였다. MRS broth에서 S. aureus와 젖산균을 혼합배양시켰을 때 모든 젖산균은 배양 12시간째부터 S. aureus의 생육을 억제하기 시작했으며, L. lactic는 24시간만에, L. casei, Sc. thermophilus 그리고 L. acidophilus는 48시간 만에 모든 균을 사멸하였다. S. aureus가 사멸하기 시작한 12시간째 혼합배양액의 pH는 4.50이었으며 완전히 사멸한 24, 48시간의 pH는 3.50이었다. TS broth에 젖산균의 대사산물을 첨가하고 S. aureus을 배양하였을 때 4종의 젖산균 대사산물 모두가 향균활성을 나타내었으며, 대사산물을 열처리하였을 때 L. casei, L. acidophilus 및 L. lactis는 그 항균활성이 소실되었으나, Sc. thermophilus의 경우는 어느 정도 그 활성을 유지하였다. $H_{2}O_{2}$의 영향을 확인하기 위해 catalase를 처리하였을 때는 L. lactis만 그 항균활성이 소실되었다. 유기산(acetate, lactate)이 무기산(HCl)보다 pH3.5, 4.5에서 S. aureus에 대한 살균활성이 더 높았으며, pH5.5, 6.5에서는 큰 차이가 없었다.

• Fisheries and Aquatic Sciences
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• 제20권4호
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• pp.6.1-6.8
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• 2017

The objective of this research was to study the effect of astaxanthin (AST) on growth performance and antioxidant capacity in golden pompano (Trachinotus ovatus) both in vivo and in vitro. In the in vivo study, two diets were formulated with or without astaxanthin supplementation (D1 and D2; 0 and 200 mg/kg) to feed fish for 6 weeks. In the in vitro study, cells from hepatopancreas of golden pompano were isolated and four treatments with or without astaxanthin and $H_2O_2$ supplementation were applied (control group: without both astaxanthin and $H_2O_2$ treated; $H_2O_2$ group: just with $H_2O_2$ treated; $H_2O_2$ + AST group: with both astaxanthin and $H_2O_2$treated; AST group: just with AST treated). Results of the in vivo study showed that weight gain (WG) and special growth rate (SGR) significantly increased with astaxanthin supplemented (P < 0.05). Feed conversion ratio (FCR) of fish fed D2 diet was significantly lower than that of fish fed D1 diet (P < 0.05). Hepatic total antioxidant capacity (T-AOC) and the reduced glutathione (GSH) of golden pompano fed D2 diet were significant higher than those of fish fed D1 diet (P < 0.05). Superoxide dismutase (SOD) was significantly declined as astaxanthin was supplemented (P < 0.05). Results of the in vitro study showed that the cell viability of $H_2O_2$ group was 52.37% compared to the control group, and it was significantly elevated to 84.18% by astaxanthin supplementation ($H_2O_2$ + AST group) (P < 0.05). The total antioxidant capacity (T-AOC) and the reduced glutathione (GSH) of cell were significant decreased by oxidative stress from $H_2O_2$ (P < 0.05), but it could be raised by astaxanthin supplementation ($H_2O_2$ vs $H_2O_2$ + AST), and the malondialdehyde (MDA) was significant higher in $H_2O_2$ group (P < 0.05) and astaxanthin supplementation could alleviate the cells from lipid peroxidation injury. In conclusion, dietary astaxanthin supplementation can improve the growth performance of golden pompano. Moreover, astaxanthin can improve the golden pompano hepatic antioxidant capacity both in vivo and in vitro study by eliminating the reactive oxygen species.

• 미생물학회지
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• 제20권4호
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• pp.195-200
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• 1982

Rhizobium japonicum was isolated from the nodule of soybean root grown at the reclaimed tidal land in Kang-Wha island. The effect of pH and salt concentration to the viability of the isolated strain were examined in relationship between microbial growth and accumulation of PHB. Optimal pH value for the good viability of the isolated strain was 7.0 and also, at 5.0 and 6.0 viability was favorable to large extent, but 9.0 was unfavorable. Examined the effect of salt concentration treated two times as of the salinity in the reclaimed tidal land, viability of the isolated strain showed about 30 to 40%. And also in treatment with NaCl(40g/l) whatever the pH value adopted, viability was mostly less than 10%. The amount of accumulated PHB was relatively high at low pH value(5-6) and at high salt concentrration, respectively.

• 한국결정성장학회지
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• 제8권2호
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• pp.342-342
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• 1998

TiCl₄수용액의 탈수 반응에 있어 pH의 영향에 관하여 연구하였다. KOH와 HCl을 탈수 촉진 및 탈수 지연제로 사용하여 실험한 결과 다음과 같은 결론을 얻었다. TiCl₄수용액과 KOH와의 반응계에서 중화점은 pH 7.4이었으며 중화점 이전에서는 반응 생성물로 polymetatitanic acid의 중합체인 Ti-gel이 생성되고 중화점 이상에서는 재탈수 반응에 의하여 oligomer화가 일어난다. 또한 결정성 potasium titanate는 존재하지 않는다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권6호
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• pp.331-334
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• 2002

Culture conductivity and on-line NADH fluorescence were used to measure cellular growth in plant cell suspension cultures of Podophyllum hexandrum. An inverse correlation between dry cell weight and medium conductivity was observed during shake flask cultivation. A linear relationship between dry cell weight and culture NADH fluorescence was obtained during the exponential phase of batch cultivation In a bioreactor under the pH stat (pH 6) conditions. It was observed that conductivity measurement were suitable for biomass characterisation under highly dynamic uncontrolled shake flask cultivation conditions. However, if the acid/alkali feeding is done for pH control the conductivity measurement could not be applied. On the other hand the NADH fluorescence measurement allowed online-in situ biomass monitoring of rather heterogenous plant cell suspension cultures in bioreactor even under the most desirable pH stat conditions.

• 대한원격탐사학회지
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• 제37권4호
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• pp.733-745
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• 2021

Although waxy corn varieties developed after the 1980s show differences depending on development stages and conditions, studies on the characteristics of waxy corn during the growth stage are rare. The subject of this study was a field survey and unmanned aerial vehicle (UAV) image acquisition of four waxy corn varieties cultivated in Idam-ri, Gammul-myeon, Goesan-gun, Korea. The study was conducted in four stages at intervals of two weeks after planting in 2019. The growth characteristics of each of the four varieties were analyzed using growth curves obtained based on field survey and UAV imagery data. The characteristics of each growth stage of the four varieties of corn, as assessed using normalized difference vegetation index (NDVI) and plant height (P.H.) values, were as follows. The growth model was identified as a model in which three-parameter logistic (3PL) curves reflect the growth characteristics of corn well. In particular, it was found that the variations in growth rate shown by P.H. and NDVI values clearly explain the differences between corn varieties. Among the four cultivars, growth and development first occurred at the early vegetative stage in Daehakchal, followed by Mibaek 2, Miheukchal, and finally Hwanggeummatchal. The variationsin P.H. and NDVI were achieved quickly and earlier in Daehakchal, followed by Mibaek 2, Hwanggeummatchal, and Miheukchal. It was confirmed that these results reflected the characteristics of the fast white-type varieties, while the black-type varieties were delayed, as in a previous study. These results reflect the resistance to lodging that affects the cultivation environment and the response characteristics to nutrients and moisture. It was confirmed that UAV accurately provides growth information that is very useful for analyzing the growth characteristics of each corn variety.

• The Plant Pathology Journal
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• 제27권3호
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• pp.266-271
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• 2011

Physicochemical characteristics and heavy metal content of soils located along the drainage way of an abandoned mine at Busan, Korea ($35^{\circ}31'N$, $129^{\circ}22'E$) (contaminated soil; CS) and uncontaminated soils (50-70 m apart from the drainage way) (NS) were examined. Growth of tomato plants (Solanum lycopersicom cv. Rutgers) in CS and NS, development of the root-knot nematode (Meloidogyne incognita) as root-knot gall formation on tomato plants, and non-parasitic nematode populations in soil were also examined. Growth of tomato plants, root-knot gall formation, and non-parasitic nematode populations were significantly reduced in CS with higher As content, lower pH, higher electrical conductivity (EC), and lower available phosphate (av. $P_2O_5$) than in NS. None of the other physicochemical characters examined differed significantly between CS and NS (low and no significance) and were above or below the critical levels detrimental to plant growth and nematode development, suggesting that As may be the primary hazardous heavy metal in CS. The toxicity of As might be enhanced at low pH in CS because exchangeable forms of some heavy metals increase with the decrease of soil pH. The heavy metals, especially As, may have contributed to increasing EC and decreasing av. $P_2O_5$. Therefore, the effects of mine drainage contamination from the abandoned mine were derived primarily from contamination by heavy metals such as As. These may have been enhanced in toxicity (solubility) by the lowered pH, increased soil salinity (EC) and decreased av. $P_2O_5$. Our results suggest synergistic adverse effects on the plant and the nematode by decreasing osmotic potential and nutrient availability.

• 치위생과학회지
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• 제6권3호
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• pp.159-162
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• 2006

이 연구의 목적은 타액이 산성일때 치아우식과 연관이 있는 Streptococcus mutans 와 Lactobacillus spp.의 양을 조사하여 치아우식의 지표로 사용될 수 있는지를 관찰한 외국인을 대상으로한 임상결과이다. 총 240개의 타액 표본들은 마케도니아(Macedonia), 스코프에(Skopje)에 위치한 St Kiril- Metodi 치과대학병원에서 환자 80명으로부터 얻었다. 표본들은 사전의 파라핀 저작(씹기)법에 의해 타액을 자극하여 얻어졌으나, 타액의 pH의 결정을 위해서 다른 자극은 사용되지 않았다. 치아우식 집단의 타액 1 ml에서 S. mutans는 100%의 confluent growth (CFU > $10^6$와 $10^4-10^5$) 였으나, Lactobacillus spp.는 78.3%였다. 대조표본 집단(건강하고 손상되지 않은 치아를 가짐)에서, confluent growth (CFU > $10^6$와 $10^5$)를 가지는 colony는 발견되지 않았다. 이와 달리, 두 집단 모두(60 + 20)에서 타액의 pH와 타액의 완충력으로부터 얻어진 결과는 상호연관이 있었다. 치아우식집단에서, 타액의 pH 결과치는 약산성(5.90 - 6.50)이었고, 타액의 완충력 역시 매우 낮았다(0.7ml 이하). 한편, 대조표본 집단에서, 타액의 pH는 중성(pH 7.01 - 7.7)이었고 타액 완충력은 높았다(1ml 이상). CRT-bacteria 시험법으로부터 얻은 타액 1 ml내($10^5$ CFU 이상)의 S. mutans와 Lactobacillus spp.의 증가된 수는 타액의 산성과 약산성 pH의 결과처럼 치아우식위험을 증가시켰다. 따라서, 타액 pH법과 완충력 측정법은 치아우식 위험을 예측 할 수 있으며, 치아우식 예방을 위해 유용한 측정법으로 사용될 수 있을 것으로 사료된다.

• 한국식품영양과학회지
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• 제22권1호
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• pp.58-61
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• 1993

Lysozyme, glycine, EDTA의 혼합첨가가 김치발효에 미치는 영향을 고찰하였다 숙성기간별로 pH 4.0에서 pH 5.0까지 김치액에 각각 120ppm lysozyme과 0.12% glycine을 첨가하였을 때 첨가구가 $10^1$~$10^4$ cfu/$m\ell$만큼 젖산균의 성장이 억제되었고 lysozyme단독 첨가구에 비해 lysozyme-glycine 혼합첨가구가 $10^1$~$10^2$cfu/$m\ell$ 만큼 더 많은 젖산균의 성장이 억제되었다. Lysozyme 단독으로 100, 200, 1,000ppm을 배추김치에 첨가하면 대조구에 비해 발효기간에 따라 pH의 감소는 둔화되었지만 말기에는 처리구간 현저한 차이는 없었다. 따라서 lysozyme-glycine 혼합 첨가하므로써 적정산도와 pH 변화가 지연되었다. 120ppm과 2mM EDTA로 나누어 첨가한 김치에 대해서도 단독구에 비해 혼합첨가구에서 $10^1$~$10^2$cfu/$m\ell$의 젖산균이 억제되었다.