• Molecules and Cells
• /
• 제19권1호
• /
• pp.81-87
• /
• 2005

Phytochelatins play an important role in heavy metal detoxification in plants as well as in other organisms. The Arabidopsis thaliana mutant cad1-3 does not produce detectable levels of phytochelatins in response to cadmium stress. The hypersensitivity of cad1-3 to cadmium stress is attributed to a mutation in the phytochelatin synthase 1 (AtPCS1) gene. However, A. thaliana also contains a functional phytochelatin synthase 2 (AtPCS2). In this study, we investigated why the cad1-3 mutant is hypersensitive to cadmium stress despite the presence of AtPCS2. Northern and Western blot analyses showed that expression of AtPCS2 is weak compared to AtPCS1 in both roots and shoots of transgenic Arabidopsis. The lower level of AtPCS2 expression was confirmed by RT-PCR analysis of wild type Arabidopsis. Moreover, no tissue-specific expression of AtPCS2 was observed. Even when AtPCS2 was under the control of the AtPCS1 promoter or of the cauliflower mosaic virus 35S promoter (CaMV 35S) it was not capable of fully complementing the cad1-3 mutant for cadmium resistance.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
• /
• pp.290-292
• /
• 2004

Heavy metal contamination has been increased in aqueous environments near many industrial facilities, such as metal plating facilities, mining operations, and tanneries. The soils in the vicinity of many military bases are also reported to be contaminated and pose a risk of groundwater and surface water contamination with heavy metals. The biological removal of metals through bioaccumulation has distinct advantages over conventional methods; the process rarely produces undesirable or deleterious chemical byproducts, it is highly efficient, easy to operate and cost-effective in the treatment of large volumes of wastewater containing toxic heavy metals. In addition, a recent development of molecular biology shed light on the enhancing the microorganism's natural remediation capability as well as improving the current biological treatment. In this study, characteristics of the cell growth and heavy metal accumulation by Saccharomyces cerevisiae strains expressing phytochelatin syntahse (PCS) gene were studied in batch cultures. The AtCRFI gene was demonstrated to confer substantial increases in metal tolerance in yeast. PCS-expressing cells tolerated more Cd$^{2＋}$ than controls.

• 한국산학기술학회논문지
• /
• 제14권6호
• /
• pp.3114-3119
• /
• 2013

망그로브 생태계는 수생태계로 유입되는 중금속을 받아들이는 기능을 가지고 있다. 중금속에 오염된 퇴적물에 노출됨에도 불구하고 망그로브는 중금속에 내성을 가지고 있다. 이 연구에서 우리는 망그로브로부터 중금속 저항성 관련 유전자를 클로닝하고, 중금속 노출에 유전자 발현 변화를 분석하였다. 미크로네시아 축라군의 웨노섬에서 채취한 Rhizophora stylosa의 잎과 뿌리조직으로부터 CTAB 방법을 이용하여 RNA를 분리하였고, gene specific primers를 이용하여 phytochelatin synthase 1(PCS1) 유전자를 클로닝하였다. R. stylosa 태생종자를 100 ppb의 Cd과 10 ppb의 Cu에 노출하였을 때 각각 1.91배 및 2.72배 발현이 증가하였다. 이러한 결과는 PCS1 유전자의 발현분석이 망그로브 생태계의 건강성을 평가하기 위한 좋은 도구가 될 수 있음을 나타낸다.

• 한국환경농학회지
• /
• 제28권4호
• /
• pp.409-411
• /
• 2009

Phytochelatins (PCs) are small-sized peptides synthesized by PC synthase (PCS) using glutathione (GSH) as a substrate, and they play an important role in the detoxification of toxic heavy metals in plants, fission yeast, and other living organisms. Recently, it has been suggested that PCS is also involved in degradation of some xenobiotics including monobromobimane. PCS cleaves the Gly residue from GSH-xenobiotics conjugates resulting in ${\gamma}$-Glu-Cys-xenobiotics, and this is to degraded further. Therefore, our research is focus on whether PCS is also involved in degradation of tolclofos-methyl, an important pesticide which has been used in ginseng cultivated areas. Heterologous expression of Arabidopsis PCS confers tolerance to tolclofos-methyl in yeast. Furthermore, PCS-deficient Cad1-3 Arabidopsis mutant showed high sensitivity to tolclofos-methyl compared with wild-type plants. These results imply that PCS is involved in degradation of tolclofos-methyl as other xenobiotics.

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 1995년도 한국생물과학협회 학술발표대회
• /
• pp.263.1-263
• /
• 1995

No Abstract, See Full Text

• Applied Biological Chemistry
• /
• 제40권3호
• /
• pp.243-248
• /
• 1997

미나리 (O. javanica)는 오염된 하수 등에서도 매우 잘 자라는 식물체이다. 이런 미나리를 phytoremediation에 응용하기 위하여 $50\;{\mu}M$ 카드늄을 처리하여 카드늄에 대한 저항성 및 식물체에 축적된 카드늄을 정량하고 생리적, 생화학적 변화를 조사하였다. 카드늄을 처리하고 3주 뒤에 미나리는 거의 성장저해를 받지 않았으나 대조구로 사용한 담배 (N. tabacum Xanthi)는 75% 성장저해를 받았다. 미나리는 뿌리, 줄기, 잎에 건중량 1 그램당 각각 2.1, 7.3, $113\;{\mu}moles$의 카드늄을 축적하였다. 카드늄을 처리한 미나리의 경우 전체 thiol 잔기의 농도가 카드늄을 처리하지 않은 미나리에 비해 뿌리, 줄기, 잎에서 각각 0.5, 1,7배 증가하였으나 글루타치온 농도의 경우는 대조구에 비해 각각 57%, 30%, 53% 까지 감소하였다. 이를 HPLC로 조사해본 결과 증가된 thiol의 함량은 새로운 thiol 잔기를 지닌 물질의 생성으로 기인된 것이고, retention time을 기초로 이는 phytochelatin인 것으로 보여진다.

• The Korean Journal of Ecology
• /
• 제26권5호
• /
• pp.263-266
• /
• 2003

This research investigated the process of removing cadmium and tested the detoxification mechanism of the cadmium-binding peptide (Cd-BP) from Rumex crispus. Phytochelatin-like cadmium-binding peptide (PC-Cd-BP) of Rumex crispus was purified and identified. Rumex crispus was exposed to 4.3 mg Cd/L for seven days. Heat-treated supernatant fraction taken by root tissues showed traces of PC-Cd-BP An analysis of the material through Gel-filteration chromatography on the Sephadex G-75 column showed two symmetrical Cd-BP peaks. The major peak with the smaller molecular weight was further purified by $C_{18}$ reverse-phase HPLC to produce apparent homogeneity. The amino acid composition of Cd-BP from Rumex crispus included cysteine (22.6%), glutamate and glutamate acid (20%), and glycine (12%). It was similar the amino acid composition of most PC. The molecular weight of the purified peptide was determined at 568-706 Da by MALDI-TOF MS. Therefore, the Cd-BP of Rumex crispus was PC-Cd-BP consisting of isopeptides.

• 환경생물
• /
• 제18권2호
• /
• pp.269-277
• /
• 2000

고마리와 소리쟁이에 Cd$^{2+}$와 Pb$^{2+}$를 각각 5 및 10mM로 5일간 처리한 결과, 고마리에서는 중금속 5mM처리구의 경우 Pb$^{2+}$가 Cd$^{2+}$보다 약 3.5배, 10mM의 경우 약 2.9배로 Pb$^{2+}$의 농축량이 높게 검출된 반면, 소리쟁이는 Cd$^{2+}$ 5mM에서 약 1.49$\mu\textrm{g}$/g, 10mM에서 약 2.90$\mu\textrm{g}$/g그리고 Pb$^{2+}$ 5mM에서 약 1.83$\mu\textrm{g}$/g, 10mM에서 약 2.73$\mu\textrm{g}$/g로 검출되어 처리농도별 Cd$^{2+}$와 Pb$^{2+}$의 농축량은 비슷하였다. 고마리와 소리쟁의 배양액(pH 6.5)에 Cd$^{2+}$와 Pb$^{2+}$를 5및 10mM로 혼합하여 처리한 후 각 실험구 토양의 중금속 잔류율과 pH는 대조구에 비해 고마리를 배양하며 Cd$^{2+}$5mM을 처리한 경우 약 77.1%와 pH 6.39, 10mM을 처리한 경우 약 90.2%와 PH 5.97 그리고 Pb$^{2+}$ 5mM을 처리한 경우 약 81.1%와 pH 6.00, 10mM을 처리한 경우 약 85.7%와 pH 5.80, 소리쟁이를 배양하며 Cd$^{2+}$ 5mM을 처리한 경우 약 83.9%와 pH 6.32, 10mM을 처리한 경우 약 93.7%와 pH 6.02 그리고 Pb$^{2+}$ 5mM을 처리한 경우 약 88.6%와 pH 6.27, 10mM을 처리한 경우 약 90.0%와 pH 6.02정도였다. Phytochelatin은 고마리와 소리쟁이에서 모두 Cd$^{2+}$와 Pb$^{2+}$ 무처리구에 비해 5와 10mM처리구에서 유도되었음을 확인하였다. 또한, 각 식물재료 내에서 중금속에 의해 유도된 Phytochelatin의 분자량은 고마리의 경우 Cd$^{2+}$에 의해서는 약 4,300-8,600 da, Pb$^{2+}$에 의해서는 약 3,200-9,700 da, 소리쟁이 의 경우 Cd$^{2+}$에서는 약 4,300 da, Pb$^{2+}$에 의해서는 약 3,200-7,500 da 정도였다.

• 한국토양환경학회지
• /
• 제5권1호
• /
• pp.33-43
• /
• 2000

고마리 서식지 토양 및 식물체 내치 중금속 함량을 조사한 결과, 서식처 토양 및 식물체 내에서 $Cd^{2+}$ 는 검출되지 않았으나 토양에서 $Pb^{2+}$는 약 7.8~12.6$mu\textrm{g}$/g로 검출되었고, 고마리의 잎에서 $Pb^{2+}$는 약 11.7~18.4$\mu\textrm{g}$/g, 줄기에서 약 7.5~15.5$\mu\textrm{g}$/g 그리고 뿌리에서 약 89.1~193.6$\mu\textrm{g}$/g로 검출되었다. 토양 내의 중금속 함량과 식물체 내의 중금속 농축량 사이에 상관계수(r)는 0.814(>t12. 0.01)로 정상관관계를 나타냈다. 고마리에 Cd$({NO_3})_2$와 Pb$({NO_3})_2$를 5와 10mM로 처리한 후, 식물체의 잎에서 중금속 함량을 분석한 결과, $Cd^{2+}$와 $Pb^{2+}$는 각각 약 0.82~2.79$mu\textrm{g}$/g와 약 2.87~8.08$mu\textrm{g}$/g로 검출되었다. 고마리 배양 후 실험토양 내의 중금속 잔류량은 $Cd^{2+}$의 경우 약 77.1~90.2%로 감소되었고, $Pb^{2+}$의 경우 약 81.1~85.7%로 감소되었다. 고마리에 중금속 물질을 처리한 후 유도.생성되는 Phytochelatin은 중금속 물질을 처리함에 따라 그 상대생성량이 증가하였다. 이들의 분자량은 $Cd^{2+}$를 처리한 경우 약 4,300~8,600da그리고 $Pb^{2+}$를 처리한 경우 약 3,200~9,700da이었다.

• 한국식물학회:학술대회논문집
• /
• 한국식물학회 2002년도 춘계학술발표대회:발표눈문요지록
• /
• pp.62-72
• /
• 2002

This study has investigated the biosynthesis and function of the heavy metal binding peptides, the phytochelatins, in plants. PCs are synthesised enzymatically from glutathione by the enzyme PC synthase in the presence of heavy metal ions. Using Arabidopsis thaliana as a model organism cadmium-sensitive, phytochelatin-deficient mutants have been isolated and characterised in previous studies. The cadl mutants have wildtype levels of glutathione, are PC deficient and lack PC synthase activity. Thus, the CADl gene has been proposed to encode PC synthase. The CADl gene was isolated by a positional cloning strategy The gene was mapped and a candidate identified. Each of four cadl mutants had a single base pair change in the candidate gene and the cadmium-sensitive, cadl phenotype was complemented by the candidate gene. This demonstrated the CADl gene had been cloned. A homologous gene in the fission yeast, Schizosaccharomyces pombe was identified through database searches. A targeted-deletion mutation of this gene was constructed and the mutant, like cadl mutants of Arabidopsis, was cadmium-sensitive and PC-deficient. A comparison of the redicted amino acid sequences reveals a highly conserved N-terminal region Presumed to be the catalytic domain and a variable C-terminal region containing multiple Cys residues proposed to be involved in activation of the enzyme by metal ions. Similar genes were also identified in animal species. The Arabidopsis CADl/AtPCSl and S. pombe SpbPCS genes were expressed in E. coli and were shown to be sufficient for glutathione-dependent, heavy metal activate PC synthesis in vitro, thus demonstrating these genes encode PC synthase enzymes. Using RT-PCR, AtPCSl expression appeared to be independent of Cd exposure. However, at higher levels of Cd exposure a AtPCSl-CUS reporter gene construct appeared to be more highly expressed. Using the reporter gene construct, AtPCSl was expressed most tissues. Expression appeared to be greater in younger tissues and same higher levels of expression was observed in some regions, including carpels and the base of siliques. AtPCS2 was a functional gene encoding an active PC synthase. However, its Pattern of expression and the phenotype of a mutant (or antisense line) have not been determined. Assuming the gene is functional then it has clearly been maintained through evolution and must provide some selective advantage. This implies that, at least in some cells or tissue, it is likely to be the dominant PC synthase expressed. This remains to be determined