本文關(guān)鍵詞： 氟環(huán)唑 斜生柵藻 對映選擇性 毒性 富集　出處：《貴州大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：氟環(huán)唑是美國巴斯夫公司于1985年開發(fā)的一種高效、低毒的三唑類手性殺菌劑,在農(nóng)業(yè)上被廣泛使用。然而,長期使用氟環(huán)唑會使其進入淡水循環(huán)造成水體污染。本實驗考察了氟環(huán)唑及其對映體對斜生柵藻的生長抑制,通過計算半最大效應(yīng)濃度(EC50)比較了氟環(huán)唑?qū)τ丑w的急性毒性大小;檢測了氟環(huán)唑?qū)τ丑w對斜生柵藻細胞內(nèi)光合色素和脂質(zhì)過氧化物丙二醛(MDA)含量、超氧化物歧化酶(SOD)和過氧化氫酶(CAT)活性的影響;利用透射電子顯微鏡(TEM)觀察了氟環(huán)唑?qū)τ丑w處理過的斜生柵藻細胞的超微結(jié)構(gòu)的變化,并探討氟環(huán)唑?qū)τ丑w的選擇性毒性效應(yīng);研究了氟環(huán)唑?qū)τ丑w在柵藻細胞中的選擇性富集和降解。結(jié)果表明:氟環(huán)唑外消旋體、(-)-對映體和(+)-對映體的96h-EC50分別為5.850,4.296和2.488 mg/L。當(dāng)給藥量較低(1 mg/L)時,rac-及(-)-氟環(huán)唑處理的藻細胞中總?cè)~綠素含量分別高于對照組14.2%和1.3%,隨著給藥量增加,藻細胞中葉綠素和類胡蘿卜素含量均降低。氟環(huán)唑及其對映體對斜生柵藻細胞的脂質(zhì)過氧化物(MDA)含量以及抗氧化物酶(SOD和CAT)活性的影響也表現(xiàn)出對映選擇性。另外,氟環(huán)唑?qū)τ丑w還會導(dǎo)致藻細胞產(chǎn)生超微結(jié)構(gòu)的改變,包括質(zhì)壁分離現(xiàn)象,葉綠體和細胞核的消失,脂肪低和淀粉顆粒的累積等。斜生柵藻可富集氟環(huán)唑,并有助于氟環(huán)唑在水中的消解。持續(xù)暴露于rac-氟環(huán)唑中的柵藻,(-)-和(+)-對映體的富集量第三天達到最大值,分別為28.4和21.6 mg/kg。之后兩對映體的富集量下降,并出現(xiàn)對映選擇性翻轉(zhuǎn)。暴露于氟環(huán)唑單體的柵藻,富集結(jié)果在整個實驗期內(nèi)未發(fā)現(xiàn)對映體互變,并且(-)-氟環(huán)唑和(+)-氟環(huán)唑單體的總富集量分別是外消旋體暴露時的1.53和1.75倍,表明氟環(huán)唑?qū)τ丑w以單體形式存在時比外消旋體形式更容易被藻細胞富集。
[Abstract]:Fluoxazole is a highly efficient and low toxic triazole chiral bactericide developed by Pasteur Company in 1985, which is widely used in agriculture. Long term use of fluoxazole will cause water pollution by entering fresh water cycle. The growth inhibition of flucyclazole and its enantiomers on S. obliquus was investigated in this experiment. The acute toxicity of flucyclazole enantiomers was compared by calculating the semi-maximum effect concentration (EC50). The effects of flucyclazole enantiomers on the contents of photosynthetic pigment, malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) in the cells of S. obliquus were determined. Transmission electron microscopy (TEM) was used to observe the ultrastructural changes of the cells treated with flucyclazole enantiomers, and to investigate the selective toxicity of flucyclazole enantiomers. The selective enrichment and degradation of flucyclazole enantiomers in algae cells were studied. The 96 h-EC50 of the enantiomers were 5.850 mg / L and 2.488 mg / L, respectively, when the dosage was lower than 1 mg / L. The content of total chlorophyll in algal cells treated with rac- and trifluocyclozole was 14.2% and 1.3 respectively higher than that in control group. The contents of lipid peroxides (MDAs) and antioxidant enzymes (SOD and CAT) in flucyclazole and its enantiomers were decreased. The effect of activity also showed enantioselectivity. Flucyclazole enantiomers also lead to ultrastructural changes in algal cells, including the separation of cytoplasm, the disappearance of chloroplasts and nuclei, low fat levels and the accumulation of starch granules, etc. It also contributes to the digestion of flucyclazole in water. The concentration of the enantiomers in rac-fluoxazole is the highest on the third day. The concentration of the enantiomers decreased and the enantioselectivity flipped after 28.4 and 21.6 mg / kg, respectively. No enantiomeric interaction was found in the whole experiment period, and the total enrichment amounts were 1.53 and 1.75 times higher than those of the racem-exposed monomers, respectively. The results showed that flucyclazole enantiomers were more easily enriched by algal cells in the form of monomers than racemes.
【學(xué)位授予單位】：貴州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X592;TQ450.26

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