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A Study of the Endocrine Disrupting Activity of Phthalate Esters using Human Cancer Cell Lines
Han, Sang-Kuk 木浦海洋大學校 2002 論文集 Vol.10 No.1
Phthalate esters have recently been added to the list of chemicals which mimic the female hormone estrogen. However, they have been tested for estrogenic activity only to a very small extent. In this study, therefore, we test to estrogenic and androgenic agonists and antagonists of phthalate esters by E-Screen and A-Screen bioassay. In the E-Screen assay, butylbenzyl phthalate (BBP), di-n-butyl phthalate (DBP), diethyl phthalate (DEP), and di-2-ethylhexyl phthalate (DEHP) showed all weakly estrogenic activity, comparing with β-estradiol-17-acetate (E₂) as positive control. Also, all of them stimulated maximally the proliferation of MCF-7 cells at a concentration of 10 μM. Other phthalate esters tested not showed estrogenic activity. In the A-Screen assay, all of phthalate esters tested showed no androgen agonistic activity. However, BBP and DBP were antiandrogenics in the antagonist assay. Our results demonstrate that hormone mimicking chemicals can have multiple hormonal activities, which may make it difficult to interpret their mechanisms of action in vivo.
Point Mutations in the Split PLC-γ1 PH Domain Modulate Phosphoinositide Binding
( Sung Kuk Kim ),( Sung Mo Wee ),( Jong Soo Chang ),( Taeg Kyu Kwon ),( Do Sik Min ),( Young Han Lee ),( Pann Ghill Suh ) 생화학분자생물학회 2004 BMB Reports Vol.37 No.6
A number of signaling molecules contain small pleckstrin homology (PH) domains capable of binding phosphoinositides or proteins. Phospholipase C (PLC)-γ1 has two putative PH domains, an NH₂-terminal (PH1) and a split PH domain (nPH₂ and cPH₂). We previously reported that the split PH domain of PLC-γ1 binds to phosphatidγ1inositol 4-phosphate (PI(4)P) and phosphatidγ1inositol 4,5-bisphosphate (PI(4,5)P₂) (Chang et al., 2002). To identify the amino acid residues responsible for binding with PI(4)P and PI(4,5)P₂, we used site-directed mutagenesis to replace each amino acid in the variable loop-1 (VL-l) region of the PLC-γ1 nPH₂ domain with alanine (a neutral amino acid). The phosphoinositide-binding affinity of these mutant molecules was analyzed by Dot-blot assay followed by ECL detection. We found that two PLC-γ1 nPH2 domain mutants, P500A and HSO3A, showed reduced affinities for phosphoinositide binding. Furthermore, these mutant PLC-γ1 molecules showed reduced PI(4,5)P₂ hydrolysis. Using green fluorescent protein (GFP) fusion protein system, we showed that both PH₁ and nPH₂ domains are responsible for membrane-targeted translocation of PLC-γ1 upon serum stimulation. Together, our data reveal that the amino acid residues Pro^(500) and His^(503) are critical for binding of PLC-γ1 to one of its substrates, PI(4,5 )P₂ in the membrane.
Chironomidae (Diptera) Fauna of Seoul-Gyeonggi Area in Korea
( Kuk Bon Na ),( Han Il Ree ),( Sang Woo Jung ),( Yeon Jae Bae ) 고려대학교 한국곤충연구소 2010 昆蟲硏究誌 Vol.26 No.-
The Chironomidae (Diptera) fauna of the Seoul-Gyeonggi area in Korea was investigated during 2003-2004. As a result, 41 species in 23 genera and 4 subfamilies including 19 new Korean records, as follows, were identified: Microtendipes tamaogouti Sasa, Microtendipes truncatus Kawai and Sasa, Paracladopelma tamahikawai Sasa, Polypedilum pedestre (Meigen), Stictochironomus sp., Micropsectra shouharasima Sasa, Neozavrelia bicoliocula (Tokunaga), Rheotanytarsus tamaquartus Sasa, Tanytarsus tamaoctavus Sasa, Tanytarsus sp., Euryhapsis subviridis (Siebert), Paratrichocladius rufiventris (Meigen), Conchapelopia quatuormaculata Fittkau, Conchapelopia sp.1, Conchapelopia sp.2, Rheopelopia maculipennis (Zetterstedt), Trissopelopia longimana (Staeger), Potthastia gaedii (Meigen), and Potthastia montium (Edward). List of species was provided with bibliographic sources and material data.