• 미생물학회지
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• 제48권2호
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• pp.57-65
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• 2012

인은 인지질, 탄수화물 및 핵산 등의 생분자 합성에 필요한 원소이다. 세균은 외부환경으로부터 인산이나 인산을 포함하는 영양소를 흡수하여 인을 얻고, 세포대사에 사용되고 남은 인산은 polyphosphate 형태로 저장한다. 현재까지 알려진 다섯 개의 인산 수송 시스템 중, 인산에 특이적으로 높은 친화력을 갖는 Pst 시스템이 가장 중요한 역할을 하며, 그 발현은 세포외부 인산 농도에 반응하는 PhoB-PhoR two component 신호전달 시스템에 의해 조절된다. 반응 조절 단백질 PhoB는 인산 대사뿐 아니라 이와 관계없는 유전자들의 전사를 조절하는 것으로 알려졌으며, 따라서 PhoB의 활성이 조절되지 않으면 많은 종류의 다른 표현형이 나타난다. 본 총설은 각 인산 수송 시스템의 기능이 결여된 세균의 표현형에 대한 최근 연구 결과를 토대로 다음과 같은 내용을 기술하였다. 첫째, 세포 내부 인산의 적정 농도 유지를 위한 인산 수송 시스템들의 역할, 둘째, 인산뿐 아니라 여타 환경 신호와 관련된 수송 시스템의 다양한 표현형, 그리고 마지막으로, 수송 시스템들 간 혹은 그 조절자들 간의 표현형 중복을 분류하여 제시하였다. 이러한 내용은 결국 세균의 대사, 적응반응 및 병원성 발현에 미치는 인산 항상성의 중요성을 강조한다.

• Asian-Australasian Journal of Animal Sciences
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• 제25권10호
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• pp.1457-1465
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• 2012

Intestinal phosphate (Pi) absorption across the apical membrane of small intestinal epithelial cells is mainly mediated by the type IIb Na-coupled phosphate co-transporter (NaPi-IIb), but its expression and regulation in the chicken remain unclear. In the present study, we investigated the mRNA and protein levels of NaPi-IIb in three regions of chicken small intestine, and related their expression levels to the rate of net phosphate absorption. Our results showed that maximal phosphate absorption occurs in the jejunum, however the highest expression levels of NaPi-IIb mRNA and protein occurs in the duodenum. In response to a low-Pi diet (TP 0.2%), there is an adaptive response restricted to the duodenum, with increased brush border membrane (BBM) Na-Pi transport activity and NaPi-IIb protein and mRNA abundance. However, when switched from a low-(TP 0.2%) to a normal diet (TP 0.6%) for 4 h, there is an increase in BBM NaPi-IIb protein abundance in the jejunum, but no changes in BBM NaPi-IIb mRNA. Therefore, our study indicates that Na-Pi transport activity and NaPi-IIb protein expression are differentially regulated in the duodenum vs the jejunum in the chicken.

• Molecules and Cells
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• 제40권10호
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• pp.697-705
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• 2017

The maintenance of inorganic phosphate (Pi) homeostasis is essential for plant growth and yield. Plants have evolved strategies to cope with Pi starvation at the transcriptional, post-transcriptional, and post-translational levels, which maximizes its availability. Many transcription factors, miRNAs, and transporters participate in the Pi starvation signaling pathway where their activities are modulated by sugar and phytohormone signaling. Environmental stresses significantly affect the uptake and utilization of nutrients by plants, but their effects on the Pi starvation response remain unclear. Recently, we reported that Pi starvation signaling is affected by abiotic stresses such as salt, abscisic acid, and drought. In this review, we identified transcription factors, such as MYB, WRKY, and zinc finger transcription factors with functions in Pi starvation and other environmental stress signaling. In silico analysis of the promoter regions of Pi starvation-responsive genes, including phosphate transporters, microRNAs, and phosphate starvation-induced genes, suggest that their expression may be regulated by other environmental stresses, such as hormones, drought, cold, heat, and pathogens as well as by Pi starvation. Thus, we suggest the possibility of cross-talk between Pi starvation signaling and other environmental stress signaling pathways.

• 식물조직배양학회지
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• 제27권6호
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• pp.441-445
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• 2000

저인산 조건하에서 인산 흡수 효율이 높은 벼 품종을 개발하고자 담배의 인산수송자 유전자를 벼에 형질전환하였다. 동진벼로부터 유도된 callus를 담배의 인산수송자 유전자가 도입된 A. tumefaciens LBA 4404와 공동배 양한 후, 선발배지에서 증식된 callus를 250 mg/L carbenicillin, 2 mg/L kinetin, 0.1 mg/L NAA가 첨가된 MS배지에 옮겨 약 2주 후부터 소식물체를 얻었다. Carbenicillin 250 mg/L 첨가된 MS 기본배지에서 소식물체의 발근을 유도하여 재분화 식물체를 얻었다. 선발된 callus는 약 52%의 식물체 재력화율을 보였다. 선발된 재분화 식물체에 대한 PCR 분석을 수행하여 형질전환 벼 식물체에 담배의 인산수송자 유전자가 삽입되었음을 확인하였다. 형질전환체의 genonlic DNA로부터 PCR에 의해 증폭된 DNA에 대한 Southern blot분석 결과, 대조 식물체에서는 band가 검출되지 않았으나 형질전환 식물체에서는 인산수송자 유전자와 동일한 1.7kb의 band가 검출되어 외래유전자인 담배 인산수송자 유전자가 안전적으로 도입되었음이 확인되었다.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2006년도 제47회 학술심포지움 및 추계국제학술대회
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• pp.45.1-45.1
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• 2006

• Journal of Microbiology and Biotechnology
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• 제30권1호
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• pp.118-126
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• 2020

Silicon and phosphorus are elements that are beneficial for plant growth. Despite the abundant availability of silicate and phosphate in the Earth's crust, crop nutritional requirements for silicon and phosphorus are normally met through the application of fertilizer. However, fertilizers are one of the major causes of heavy metal pollution. In our study, we aimed to assess silicate and phosphate solubilization by the bacteria Enterobacter ludwigii GAK2, in the presence and absence of phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), to counteract cadmium stress in rice (Oryza sativa L). Our results showed that the GAK2-treated rice plants, grown in soil amended with phosphate [Ca₃(PO₄)₂] or silicate (Mg₂O₈Si₃), had significantly reduced cadmium content, and enhanced plant growth promoting characteristics including fresh shoot and root weight, plant height, and chlorophyll content. These plants showed significant downregulation of the cadmium transporter gene, OsHMA2, and upregulation of the silicon carrier gene, OsLsi1. Moreover, jasmonic acid levels were significantly reduced in the GAK2-inoculated plants, and this was further supported by the downregulation of the jasmonic acid related gene, OsJAZ1. These results indicate that Enterobacter ludwigii GAK2 can be used as a silicon and phosphorus bio-fertilizer, which solubilizes insoluble silicate and phosphate, and mitigates heavy metal toxicity in crops.

• Molecules and Cells
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• 제41권4호
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• pp.351-361
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• 2018

Sucrose is a crucial compound for the growth and development of plants, and the regulation of multiple genes depends on the amount of soluble sugars present. Sucrose acts as a signaling molecule that regulates a proton-sucrose symporter, with its sensor being the sucrose transporter. Flavonoid and anthocyanin biosynthesis are regulated by sucrose, and sucrose signaling can affect flavonoid and anthocyanin accumulation. In the present study, we found a Myb transcription factor affecting accumulation of anthocyanin. AtMyb56 showed an increase in its expression in response to sucrose treatment. Under normal conditions, anthocyanin accumulation was similar between Col-0 (wild type) and atmyb56 mutant seedlings; however, under sucrose treatment, the level of anthocyanin accumulation was lower in the atmyb56 mutant plants than in Col-0 plants. Preliminary microarray analysis led to the investigation of the expression of one candidate gene, AtGPT2, in the atmyb56 mutant. The phosphate translocator, which is a plastidial phosphate antiporter family, catalyzes the import of glucose-6-phosphate (G-6-P) into the chloroplast. AtGPT2 gene expression was altered in atmyb56 seedlings in a sucrose-dependent manner in response to circadian cycle. Furthermore, the lack of AtMyb56 resulted in altered accumulation of maltose in a sucrose-dependent manner. Therefore, the sucrose responsive AtMyb56 regulates AtGPT2 gene expression in a sucrose-dependent manner to modulate maltose and anthocyanin accumulations in response to the circadian cycle.

• 한국미생물·생명공학회지
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• 제35권4호
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• pp.272-277
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• 2007

P. pastoris는 대장균에 비해 정확한 접힘, 당화, 효율적인 분비기작등의 장점을 가지고 있어 재조합 단백질의 생산을 위한 균주로서 관심을 받고 있다. 또한 재조합 단백질의 효율적인 생산공정 개발을 위하여 배양공정 중 특정 시간이나 조건에서 발현될 수 있는 효율적인 유도성 프로모터의 개발도 중요 관심 분야이다. 본 연구에서는 연속배양을 이용하여 P. pastoris의 배양 중 특정 기질이 소모되었을 때 발현되는 자동 유도성 프로모터를 개발하기 위하여, 인산이 고갈되었을 때 과발현 되는 유전자들을 탐색하였다. 인산 제한 연속배양의 정상상태에서 얻어진 균체로 부터 total RNA와 mRNA를 분리하였고, 이로부터 cDN를 합성하여 인산제한조건에서 과발현되는 유전자들을 확보하였다. 그 중 빈도수가 높은 8종의 유전자 3-phosphoglycerate kinase, glyceraldehyde 3-phosphate dehydrogenase(GAPDH), glucokinase, thiol-specific antioxidant protein, triosephosphate isomerase, sodium/phosphate symporter(NPS) 그리고 pyruvate decarboxylase를 선별하였고, Northern blot analysis를 수행한 결과 인산 섭취에 관련된 NPS 유전자가 인산제한조건에서 과발현 됨을 확인하였다. 본 연구실에서는 자동유도성 프로모터로서 NPS유래의 프로모터의 잠재성을 알아보기 위하여, 관련 유전자를 확보하여 외래 유전자를 이용한 발현연구를 진행 중이다.

• 대한임상검사과학회지
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• 제41권2호
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• pp.83-92
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• 2009

This study was undertaken to examine the effect of oxidants on membrane transport function in renal epithelial cells. Hydrogen peroxide ($H_2O_2$) was used as a model oxidant and the membrane transport function was evaluated by measuring $Na^+$-dependent phosphate ($Na^+$-Pi) uptake in opossum kidney (OK) cells. $H_2O_2$ inhibited $Na^+$-Pi uptake in a dose-dependent manner. The oxidant also caused loss of cell viability in a dose-dependent fashion. However, the extent of inhibition of the uptake was larger than that in cell viability. $H_2O_2$ inhibited $Na^+$-dependent uptake without any effect on $Na^+$-independent uptake. $H_2O_2$-induced inhibition of $Na^+$-Pi uptake was prevented completely by catalase, dimethylthiourea, and deferoxamine, suggesting involvement of hydroxyl radical generated by an iron-dependent mechanism. In contrast, antioxidants Trolox, N,N'-diphenyl-p-phenylenediamine, and butylated hydroxyanisole did not affect the $H_2O_2$ inhibition. Kinetic analysis indicated that $H_2O_2$ decreased Vmax of $Na^+$-Pi uptake with no change in the Km value. Phosphonoformic acid binding assay did not show any difference between control and $H_2O_2$-treated cells. $H_2O_2$ also did not cause degradation of $Na^+$-Pi transporter protein. Reduction in $Na^+$-Pi uptake by $H_2O_2$ was associated with ATP depletion and direct inhibition of $Na^+$-$K^+$-ATPase activity. These results indicate that the effect of $H_2O_2$ on membrane transport function in OK cells is associated with reduction in functional $Na^+$-pump activity. In addition, the inhibitory effect of $H_2O_2$ was not associated with lipid peroxidation.

• 한국식물생명공학회:학술대회논문집
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• 한국식물생명공학회 2006년도 한국육종학회 공동심포지엄 및 학술대회
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• pp.37-38
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• 2006