• 한국육종학회지
• /
• 제42권4호
• /
• pp.351-356
• /
• 2010

Brachypodium distachyon is rapidly emerged in biological study and has been currently used as a model system for genetics and functional studies for crop improvement and biofuel production. Phosphinothricin (PPT) has been widely used as a selectable agent, which raises ammonium content and induces toxicity in non-transformed plant cells. However PPT selection is not much effective on Brachypodium callus consequently reducing transformation efficiency. In order to identify the efficient conditions of PPT selection, calli obtained from mature seeds of Brachypodium (PI 254867) were cultured on the callus inducing medium (CIM) or regeneration medium (ReM) containing serial dilutions of the PPT (0, 2, 5, 10, and 15 mg/l) in dark or light condition. Callus growth and ammonium content of each treatment were measured 2 weeks after the treatment. Although callus growth and ammonium content did not show much difference in CIM, slow callus growth and increased ammonium accumulation were found in ReM. No significant difference of ammonium accumulation in response to PPT was found between dark and light conditions. In order to identify major factors affecting increased ammonium accumulation, callus was cultured on the media in combined with phytohormones (2,4-D or kinetin) and carbon sources (sucrose or maltose) containing with PPT (5 mg/l). The highest ammonium content in callus was found in the kinetin and maltose media.

• 한국습지학회지
• /
• 제7권4호
• /
• pp.33-42
• /
• 2005

Wetlands often function as a nutrient sink. It is well known that increased input of nutrient increases the primary productivity but it is not well understood what is the fate of produced biomass in wetland ecosystem. Water and sediment quality, decomposition rate of cellulose, and sediment accumulation rate in 11 montane marshes in northern Sierra Nevada, California were analyzed to trace the effect of nitrogen and phosphorus content in water on nutrient dynamics. Concentrations of ammonium, nitrate, soluble reactive phosphorus (SRP) in water were in the range of 27 to 607, 8 to 73, and 6 to 109 ppb, respectively. Concentrations of ammonium, calcium, magnesium, sodium, and potassium in water were the highest in Markleeville, which has been impacted by animal farming. Nitrate and SRP concentrations in water were the highest in Snow Creek, which has been impacted by human residence and a golf course. Cellulose decomposition rates ranged from 4 to 75 % per 90 days and the highest values were measured in Snow Creek. Concentrations of total carbon, nitrogen, and phosphorus in sediment ranged from 8.0 to 42.8, 0.5 to 3.0, and 0.076 to 0.162 %, respectively. Accumulation rates of carbon, nitrogen, and phosphorus fluctuated between 32.7 to 97.1, 2.4 to 9.0, and 0.08 to $1.14gm^{-2}yr{-1}$, respectively. Accumulation rates of carbon and nitrogen were highest in Markleeville and that of phosphorus was highest in Lake Van Norden. Correlation analysis showed that decay rate is correlated with ammonium, nitrate, and SRP in water. There was no correlation between element content in sediment and water quality. Nitrogen accumulation rate was correlated with ammonium in water. These results showed that element accumulation rates in montane wetland ecosystems are determined by decomposition rate rather than nutrient input. This study stresses a need for eco-physiological researches on the response of microbial community to increased nutrient input and environmental change because the microbial community is responsible for the decomposition process.

• 한국잡초학회지
• /
• 제30권4호
• /
• pp.380-389
• /
• 2010

본 연구는 유전자총기법에 의해 생산된 형질전환 고구마를 사용하여 glufosinate-ammonium에 대한 저항성 유무를 빠르고, 경제적이며, 신뢰할 수 있는 간이분석법을 찾고자 수행되었다. 저항성 진단법은 whole-plant 진단법, one leaf 진단법 및 leaf disk 진단법을 사용하였고, 이들 진단법에 의해 glufosinateammonium을 처리하고 잎의 피해율과 암모늄 축적량을 조사하였다. Leaf disk 진단법에서 glufosinateammonium 처리 후 형질전환 라인 7171의 잎에 대한 약해는 wild type에 비해 1.9배 낮았다. One leaf 진단법과 whole plant 진단법의 경우 glufosinateammonium 처리 후 7171의 잎에 대한 약해는 wild type에 비해 각각 59배와 92배 적었다. Leaf disk, one leaf와 whole plant 진단법에서 0.5-5mM glufosinateammonium 처리 후 암모늄 축적은 wild type이 7171에 비해 각각 2-20, 4-43 및 6-115배 더 많이 축적되었다. 이들 3가지 방법 모두 형질전환 고구마에 대한 glufosinate-ammonium 저항성 유무를 판단하는데 가능한 방법이나 one leaf 진단법이 가장 간편하면서 빠른 진단방법이었다. 그러나 이 방법은 엽령별 내성차이가 존재할 수 있어 고구마 엽이 10개 전개되었을 때 1, 3, 5, 7, 9엽을 각각 채취하여 3mM glufosinateammonium을 처리시 잎의 피해율과 암모늄 축적을 엽령별로 조사한 결과 유의적인 차이를 보이지 않았다. 따라서 분석에 소요되는 기간, 시료량, 정확성 등을 고려할 때 형질전환 고구마의 저항성을 판별하는데 one leaf 진단법이 가장 적합한 것으로 판명 되었다.

• Weed & Turfgrass Science
• /
• 제1권4호
• /
• pp.50-56
• /
• 2012

본 연구의 목적은 bar 유전자를 발현한 형질전환벼에 대한 글루타민 합성효소 저해제인 glufosinate-ammonium, L-metionine sulfoximine과 광합성저해제인 paraquat에 저항성 수준과 형질전환벼와 비형질전환벼의 암모늄 축적량, 저온반응 및 수량을 비교하는데 있다. 형질전환벼 계통은 비형질전환벼에 비해 glufosinate-ammonium에 45~95배 높은 저항성을 보였다. 한편 형질전환벼 계통은 L-metionine sulfoximine을 처리했을 때도 형질전환벼 계통이 비형질전환벼에 비해 18배 이상의 저항성을 보여 교차저항성이 있음을 확인할 수 있었다. 그러나 glufosinate-ammonium과 작용기작이 다른 제초제인 paraquat에 대한 다중저항성은 없었다. Glufosinate-ammonium 처리에 의해 ammonium 축적은 비형질전환벼에서 증가하였으나 모든 형질전환벼의 계통에서는 적거나 효과가 없었다. 형질전환벼 계통 258, 411, 607 및 608을 제외한 계통은 비형질전환벼에 비해 저온 내성 및 저온 후 회복정도가 유의적으로 낮은 경향을 보였다. 형질전환벼 계통 142, 144, 258 및 608의 수량은 비형질전환벼와 유사하거나 높았다.

• Journal of Microbiology and Biotechnology
• /
• 제8권4호
• /
• pp.301-304
• /
• 1998

Methylobacterium organophilum can use nitrogen in the form of ammonium ions ($($NH_4$)_2SO_4\;and\;NH_4Cl) and from nonammonium sources such as glycine, alanine, peptone, and yeast extract. When potassium was limited, significantly more PHB was produced when the ammonium ion was the nitrogen source rather than a nonammonium form. With ammonium, the amount of PHB produced was 0.50-0.53 g PHB/l or $52.0~53.2\%$ of the dry cell weight. If nitrogen was from a nonammonium source, the respective values were 0.04~0.06 g PHB/1 or $8.1~11.3\%$ of dry cell weight. When ammonium sulfate was the sole source of nitrogen under potassium-limited conditions, cell growth and PHB accumulation increased as the pH increased from 6.0 to 7.5. Cell growth and PHB amount at pH 7.5 were 2.50 g dry cell weight/1 and 1.40 g PHB/1, respectively.

• 한국물환경학회지
• /
• 제22권3호
• /
• pp.482-491
• /
• 2006

The anaerobic ammonium oxidation (ANAMMOX) from substrates with various $NO_2-N$ and $NH_4-N$ concentationes, which were generated from piggery waste was accomplished by using anaerobic granular sludge as seeding sludge. As the result of operation, when $NO_2-N/NH_4-N$ ratios of ANAMMOX influent were 0.6~1.5, $NO_2-N/NH_4-N$ removal ratios were exhibited 1.19~2.07 (average 1.63). The higher influent $NO_2-N/NH_4-N$ ratios resulted in higher $NO_2-N/NH_4-N$ removal ratios by ANAMMOX. It means that $NO_2-N$ concentration is very important factor in ANAMMOX. Specific ammonium removal rate was constantly as $0.03{\sim}0.04gNH_4-N/g$ VSS-day at $35^{\circ}C$ while it was $0.01gNH_4-N/g$ VSS-day at $20{\sim}30^{\circ}C$. Thus, in order to reduce the effluent N concentration, either an increase of ANAMMOX reactor HRT or more biomass accumulation at the optimal temperature can be considered.

• 대한토목학회논문집
• /
• 제26권4B호
• /
• pp.427-432
• /
• 2006

생물학적 질산화 과정에서 비이온성 용존 암모나아(FA) 농도와 온도가 아질산 이온($NO_2{^-}$) 축적에 미치는 영향을 연구하였다. 암모늄 산화와 아질산 축적조건을 파악하기 위하여 암모늄 이온($NH_4{^-}$) 농도와 온도를 탈리한 다양한 FA 농도 조건에서 질산화 실험을 실시하였다. 암모늄산화균과 아질산산화균의 활성화에너지를 산정한 결과, 암모늄산화균의 활성화에너지는 $20^{\circ}C$ 이하에서 81.7 KJ/mol, $20^{\circ}C$ 이상에서는 32.5 KJ/mol로 차이가 있었으나, 아질산산화균의 활성화에너지는 온도에 관계없이 35.5 KJ/mol로 나타났다. 특히, FA 농도와 온도에 따른 질산화 실험결과, FA 농도에 의한 질산화 저해 및 아질산이온 축적 효과는 극히 미미하였으며, 온도조건이 아질산 이온 축적에 큰 영향을 미치는 것으로 나타났다.

• Journal of Microbiology and Biotechnology
• /
• 제9권2호
• /
• pp.140-146
• /
• 1999

When methanol was the sole carbon source, Methylobacterium organophilum NCIB 11278, a facultative methylotroph, accumulated Poly-$\beta$-hydroxybutyrate (PHB) as 59% (w/w) of dry cell weight under potassium limitation, 37% under sulfate limitation, and 33% under nitrogen limitation. Based on a stoichiometric analysis of PHB synthesis from methanol, it was suspected that PHB synthesis is accompanied by the overproduction of energy, either 6-10 ATP and 1 $FADH_2$ or 6 ATP and 3 NADPH to balance the NADH requirement, per PHB monomer. This was confirmed by observation of increased intracellular ATP levels during PHB accumulation. The intracellular ATP with limited potassium, sulfate, and ammonium increased to 0.185, 0.452, and 0.390 $\mu$moles ATP/g Xr (residual cell mass) during PHB accumulation, respectively. The intracellular ATP level under potassium limitation was similar to that when there was no nutrient limitation and no PHB accumulation, 0.152- 0.186 $\mu$moles ATP/g Xr. We propose that the maximum PHB accumulation observed when potassium was limited is a result of the energy balance during PHB accumulation. Microorganisms have high energy requirements under potassium limitation. Enhanced PHB accumulation, in ammonium and sulfate limited conditions with the addition of 2,4-dinitrophenol, which dissipates surplus energy, proves this assumption. With the addition of 1 mM of 2,4-dinitrophenol, the PHB content increased from 32.4% to 58.5% of dry cell weight when nitrogen limited and from 15.1 % to 31.0% of dry cell weight when sulfate limited.

• 한국물환경학회지
• /
• 제30권1호
• /
• pp.1-7
• /
• 2014

The purpose of this study was to investigate the nitrification characteristics of biological aerated filter (BAF) packed with ceramic media, especially focusing on nitrite build-up during nitrification. When increasing the nitrogen load above $1.63kgNH_4{^+}-N/m^3{\cdot}d$, ammonium removal efficiency decreased to less than 60% and the nitrite ratio ($NO_2{^-}-N/NO_x-N$) of higher than 75% was achieved due to the inhibitory free ammonia (FA, $NH_3-N$) concentration and oxygen limitation. FA inhibition, however, is not recommended strategy to promote nitrite build-up since FA concentration in the reactor is coupled with decreased ammonium removal efficiency. Nitrite ratio in the effluent was also affected by aeration rate and influent ammonium concentration. Ammonium oxidation was enhanced at a higher aeration rate regardless of influent ammonium concentration but, the nitrite ratio was dependent on both aeration rate and influent ammonium concentration. While a higher nitrite ratio was obtained when BAFs were fed with $50mgNH_4{^+}-N/L$ of influent, the nitrite ratio significantly decreased for a greater influent concentration of $200-300mgNH_4{^+}-N/L$. Taken together, aeration rate, influent ammonium concentration and FA concentrations kept in the BAF were found to be critical variables for nitrite accumulation in the BAF system.

• 대한환경공학회지
• /
• 제35권1호
• /
• pp.57-63
• /
• 2013

고농도 질소를 함유한 하 폐수를 아질산염 축적 경로를 통하여 처리하고자 생물막공정과 연속혼합반응조의 탈질공정을 결합하여 운전하였다. 생물막 반응조의 폴리에틸렌 담체 표면에 아질산염 산화균에 비해서 암모늄 산화균의 성장을 촉진하여 아질산염을 선택적으로 축적하고자 반응조 온도를 $35^{\circ}C$로 유지하면서 석달 이상 장기간 운전하였음에도 불구하고 유입수 암모늄(500 mg-N/L)의 일부만 아질산염(240 mg-N/L)으로 전환되었다. 하지만 pH를 7.5에서 8.0으로 증가시켰을 때, 아질산염 산화균들이 높은 암모니아 농도에 성장 저해를 받아 생물막 공정에서 아질산염 축적을 성공적으로 이끌어낼 수 있었다. 생물막 공정의 수리학적 체류시간을 12시간으로 운전하였을 때, 반응조의 성능이 급격하게 저하되어 유입수의 암모늄이 완전히 산화되지 않았다. 하수슬러지의 생분해성을 높이기 위해서 다양한 가용화 기술을 적용한 결과, 알칼리와 초음파 처리를 순차적으로 병합하였을 때, 가장 높은 가용화율(58%)을 얻을 수 있었으며, 이를 탈질반응조의 외부탄소으로 사용하였다. FISH 분석결과로부터 담체표면에 암모늄 산화균인 Nitrosomonas와 Nitrospirar계열의 미생물들이 우점종이었으며 일부 아질산염 산화균인 Nitrobacter 계열의 미생물도 소량이지만 관찰되었다.