• 원예과학기술지
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• 제28권3호
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• pp.409-414
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• 2010

배액전극 제어법을 이용한 토마토 펄라이트 자루재배에서 일중 첫 배액시각을 조절함으로써 적정관수법을 도출하고 배양액을 절감하기 위해 수행되었다. 배액전극 제어법은 다양한 일일 적산일사량, 온도, 습도에서도 식물체의 요구에 능동적으로 급액회수가 변하며 배지의 무게가 안정적으로 유지되었다. 작물의 생육특성상 목표한 첫 배액시각을 정확히 맞추는 것은 어려웠으며, 일중 첫 배액시각을 10시로 제어한 급액처리에서 전후 20분, 10시30분으로 제어한 급액처리에서 전후 50분 정도의 오차범위를 나타내었다. 일중 첫 배액시각은 고려하지 않고 30분 이내에는 관수가 반복되지 않도록 제어한 처리에서는 일중 첫 배액시각은 일정하지 않았으나 실험기간동안 오전 중 첫배액 발생이 고르게 나타났다. 배액전극 제어법은 타이머법에 비해 배액율이 비교적 균일하게 유지되었고, 수분이용효율과 비료이용효율의 분석 결과 매우 경제적인 급액방법이었다. 생육과 총수확량, 당도 등은 처리간 차이가 뚜렷하지 않았으나, 평균과중은 배액전극 제어법이 타이머법보다 컸다.

• 농업생명과학연구
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• 제44권5호
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• pp.129-135
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• 2010

기존의 타이머제어법과 일사량제어법 (ISR), 수분장력이나 수분함량센서를 사용하는 방법이 아닌 새로운 저가 정밀 급액관리법을 개발하고자 수행하였다. 본 논문은 배액전극제어법 (집액용기 안의 배액 높이에 따라 설정된 센서에 의해 급액)의 급액제어 기술을 개발하여 경제성과 환경문제를 고려할 수 있는 효율적인 급액관리 시작기를 개발하고자 하였다. 제작된 고형배지경 급액관리기 시작기의 특징은 재배틀과 수위센서 및 간단한 제어반에 의해 구성되어지며 암면, 펄라이트, 피트, 코이어 등 모든 고형배지경 수경재배에 적용할 수 있다. 장점은 저렴하고 제어원리가 간단하며 식물체와 직접적으로 연계되어 있어서 배지의 수분관리에 최적이며 유지보수가 용이하다는 점이다. 기계의 구성은 센서가 총 4개이며 4군데의 서로 다른 구역을 정하여 급액 제어할 수 있다. 센서의 형태는 2접점의 간단한 수위센서 이며 외부 배액수 위에 의한 On/Off 접점식이다. 급액단계를 3단계로 나누어 급액시간과 량을 조정할 수 있다.

• Journal of Microbiology and Biotechnology
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• 제3권2호
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• pp.123-128
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• 1993

The polyesters (polyhydroxyalkanoates; PHAs) production capability in a two-step cultivation of Alcaligenes eutrophus H16(ATCC 17699) was investigated by using various organic carbon sources. The carbon sources used included linear $C_2~C_10$ monocarboxylic acids, $C_3~C_10$ dicarboxylic acids, crotonic acid, and several linear vicinal and $\omega$-diols. The polyesters synthesized were characterized by 500 MHz $^1 H-NMR$ spectroscopy, intrinsic viscosity$[\eta]$ measurement in chloroform and differential scanning calorimetry (DSC). The PHAs synthesis data showed that the use of C-odd ($C_3, C_5, and C_7$) monocarboxylic acids resulted in poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(P(3HB-co-3HV) (3HV content ranging 40 to 70 mol%) while the use of $C_9$ substrate gave the copolyester containing only 4 mol% of 3HV. All culture products obtained on $C_3$~C$_{10}$ dicarboxylic acids gave exclusively P(3HB). 500 MHz $^1 H-NMR$ analysis showed that all polyesters synthesized generally contained 1~2 mol% 3HV even for the unrelated substrates such as the carboxylic acids with even number of carbon. When $\alpha, \omega$-diols with even number of carbon were used as substrates, 4-hydroxybutyrate(4HB) was inserted into the polyester chain composed of P(3HB-co-4HB). Vicinal diols were generally not utilized by the bacterium for polyester production.n.

• Asian-Australasian Journal of Animal Sciences
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• 제20권2호
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• pp.200-207
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• 2007

In vitro rumen incubation studies were conducted to determine effects of initial pH on bacterial attachment and fiber digestion. Ruminal fluid pH was adjusted to 5.7, 6.2 and 6.7, and three major fibrolytic bacteria attached to rice straw in the mixed culture were quantified with real-time PCR. The numbers of attached and unattached Fibrobacter succinogenes, Ruminococcus flavefaciens and Ruminocococcus albus were lower (p<0.05) at initial pH of 5.7 without significant difference between those at higher initial pH. Lowering incubation media pH to 5.7 also increased bacterial numbers detached from substrate regardless of bacterial species. Dry matter digestibility, gas accumulation and total VFA production were pH-dependent. Unlike bacterial attachment, maintaining an initial pH of 6.7 increased digestion over initial pH of 6.2. After 48 h in vitro rumen fermentation, average increases in DM digestion, gas accumulation, and total VFA production at initial pH of 6.2 and 6.7 were 2.8 and 4.4, 2.0 and 3.0, and 1.2 and 1.6 times those at initial pH of 5.7, respectively. The lag time to reach above 2% DM digestibility at low initial pH was taken more times (8 h) than at high and middle initial pH (4 h). Current data clearly indicate that ruminal pH is one of the important determinants of fiber digestion, which is modulated via the effect on bacterial attachment to fiber substrates.

• 한국수소및신에너지학회논문집
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• 제16권1호
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• pp.17-24
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• 2005

We experimented on growth in light and production of hydrogen and organic matters in dark fermentation by using C. reinhardtii. In the light, growth rate of C. reinhardtii following $CO_2$ fixation was proportional to consumption rate of nitrogen source. And the starch in cell was accumulated more when the period of culture was lengthened more. But the accumulation rate of starch in cell was decreased when the growth rate of cell become dull. In the dark fermentation, the production volume and production rate of hydrogen were the highest value in the mid exponential state among other states. The utilization efficiency of substrate was better in the early exponential state than other states. In production of organic matters, acetic acid didn't change remarkably and ethanol showed the highest value in early exponential state.

• 농업과학연구
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• 제39권1호
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• pp.35-41
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• 2012

This research was conducted to investigate the influence of organic bed soil substrates on growth and yield of organically grown ginseng transplantation in a shaded plastic houses. The pH and EC of the substrates used for this study were 5.93-6.78 and 0.03-0.15 dS/m, respectively. The concentrations of NH4-N and $NO_3$-N were 14.01-68.63 mg/L, 5.60-58.83 mg/L respectively. and the average quantum in the shaded plastic houses was 11-15% of natural light. The maximum temperature in the shaded plastic houses is higher ($3-7^{\circ}C$) than that of outside open field from the last part of April to early in August. Emergence date of ginseng was on March 21 in the mongolian type shaded plastic house, and was on March 29 in normal type shaded plastic house. Both roots and shoot growth of ginseng were excellent in the bed soils with PPV-2, compared with other compounds used. We concluded that the PPV-2 could be promising a good bed soil substrate for organic ginseng cultivation in shaded plastic house.

• 한국버섯학회지
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• 제7권1호
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• pp.27-36
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• 2009

본 연구의 목적은 온도, pH, 탄소원, 질소원 그리고 기질에 따른 아위버섯(Pleurotus ferulae )의 균사 생장 특성을 이해하는 것이었다. 아위버섯의 균사생장에는 MEA(malt extract agar)배지가 가장 효과적이었고, 균사생장에 최적온도 범위는 $25{\sim}30^{\circ}C$, 최적 pH는 6.0~8.0 이지만 균주에 따라 차이가 있었다. 아위버섯 균사 생장에 효과적인 탄소원으로는 arabinose, 질소원으로는 arginine 이었다. 그리고 균사생장에 효과적인 기질은 참나무 톱밥과 면실피를 8: 2의 비율로 섞은 배지였다.

• Journal of Microbiology and Biotechnology
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• 제27권12호
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• pp.2190-2198
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• 2017

Thermoactinomyces sp. strain YT06 was isolated from poultry compost and observed to degrade integral chicken feathers completely at $60^{\circ}C$, resulting in the formation of 3.24 mg/ml of free amino acids from 50 ml of culture containing 10 g/l chicken feathers. Strain YT06 could grow and secrete keratinase using feather as the only carbon and nitrogen sources without other supplement, but complementation of 10 g/l sucrose and 4 g/l $NaNO_3$ increased the production of the keratinolytic enzyme. The maximum protease activity obtained was 110 U/ml and for keratinase was 42 U/ml. The keratinase maintained active status over a broad pH (pH 8-11) and temperature ($60-75^{\circ}C$). It was inhibited by serine protease inhibitors and most metal ions; however, it could be stimulated by $Mn^{2+}$ and the surfactant Tween-20. A reductive agent (${\beta}$-mercaptoethanol) was observed to cleave the disulfide bond of keratin and improve the access of the enzyme to the keratinaceous substrate. Zymogram analysis showed that strain YT06 primarily secreted keratinase with a molecular mass of approximately 35 kDa. The active band was assessed by MALDI-TOF mass spectrometry and was observed to be completely identical to an alkaline serine protease from Thermoactinomyces sp. Gus2-1. Thermoactinomyces sp. strain YT06 shows great potential as a novel candidate in enzymatic processing of hard-to-degrade proteins into high-value products, such as keratinous wastes.

• 한국미생물·생명공학회지
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• 제37권2호
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• pp.105-109
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• 2009

단백질 인산화를 통한 세포내 신호전달기구 중 serine/threonine kinase에 속하는 Akt/PKB는 세포 생존과 사멸, 당대사 등을 조절하는 것으로 알려져 있다. 이러한 이유로, Akt/PKB 단백질은 천연물질들로부터 항암제를 탐색하기 위한 한 가지 target으로 사용되어 왔다. 본 연구에서는 Akt/PKB 단백질을 대량으로 생산하기 위하여 대장균의 단백질 발현 시스템을 이용하여 human Akt/PKB 단백질을 발현시켰다. 대장균에서 대량 발현된 Akt는 일반적인 조건에서는 inclusion body를 형성하였다. 배양온도 $27^{\circ}C$에서 0.01-0.09 mM IPTG로 발현 유도 시 발현된 human Akt/PKB 단백질 상당 부분이 가용화 되었다. 발현된 Akt kinase를 $Ni^{2+}$-NTA agarose column으로 정제하고, anti-Akt antibody를 이용하여 정제된 단백질이 Akt kinase 임을 확인하였다. 정제된 human Akt/PKB 단백질은 세포추출물에 존재하는 인산화 단백질을 이용하여 in vitro에서 인산화 되었으며, 인산화된 활성형 human Akt/PKB protein kinase는 human Akt/PKB protein kinase 특이 형광 peptide를 특이적으로 인산화하였다.

• 한국가축번식학회지
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• 제19권1호
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• pp.55-63
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• 1995

The putative totipotency germ cells has a relative abundance of alkaline phosphatases. Thus, histological staining of AP activity offers a new route to isolate totipotent cells and also provides insights into culture systems of these cells. Furthermore, the AP staining technique is simple and fast, requires only the napthol AS/MS substrate in combination with trapping diazonium salts such as fast red or fast blue. However, our unexpected finding was that AP staining of mouse ES cells were detected in the undifferentiaed epiblast-derived cells as well as several types of differentiating cells. This findings are different from results of Talbot et al. (1993) reported usefulness of the AP staining and implies that histological staining of AP may not by useful to determine undifferentiaed state or totipotency of ES cells. Thus, we have investigated the patterns of AP expression by RT-PCR in order to identify a marker of undifferentiated ES/primordial germ (PG) cells. In RT-PCR analysis, embryonic (E)-AP was detected only in undifferentiated ES cells, but intestinal(I)-AP was not detected in all of the examined ES and PG cells. In addition, nonspecific (NS)-AP wasdetected in undifferentiated PG cell from day 7, 5 to 13 of gestation. Histological activity of AP in ES cells was completely suppressed by addition of L-phenylalanine (Phe), L-homoarginine (Har), and L-phenylalanylglycylglycine (PheGlyGly) as an inhibitor, but RT-PCR showed the same results as in the absence of an inhibitors. Our findings suggested that expression of E-AP and NS-AP may use as a marker to determine the undifferentiated status in ES and PG cells.