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1.
以天竺葵(Pelargoniumsp.Frensham)为材料,通过在天竺葵的叶绿体中过量表达来自甲基营养型酵母同化甲醛(HCHO)途径的关键基因二羟基丙酮激酶基因(DAS)和二羟基丙酮合酶基因(DAK),获得具有DAS/DAK HCHO同化途径的转基因天竺葵,利用13 C-NMR技术对液体H13 CHO胁迫下野生型和转基因天竺葵H13 CHO代谢产物进行了比较分析,并测定了气体HCHO胁迫下野生型和转基因天竺葵的生理生化指标。结果显示:(1)2mmol·L-1液体H13 CHO胁迫下,过表达DAS/DAK基因增强了卡尔文循环在转基因天竺葵H13 CHO代谢中的作用,使糖类物质生成量增加约2.85倍,同时改变了天竺葵中原有HCHO代谢途径。(2)48μg·L-1的气体HCHO胁迫下,转基因天竺葵叶片中H2O2、丙二醛和蛋白羧基的含量显著小于野生型。(3)在环境污染气体HCHO的胁迫下,转基因天竺葵叶片的HCHO吸收效率和气孔传导率显著高于野生型。研究表明,过表达DAS/DAK基因能够有效地提高天竺葵净化环境中污染气体HCHO的能力。  相似文献   

2.
很多研究结果证实常春藤可以有效吸收气体甲醛,本研究结果表明常春藤叶片也可以有效吸收液体甲醛,甲醛吸收量和时间呈指数函数关系。2、4、6mmol·L-1液体甲醛处理均在常春藤叶片内诱发氧化胁迫,但2mmol·L-1液体甲醛胁迫在常春藤叶片内诱发的氧化胁迫水平较低。此外,2mmol·L-1液体甲醛胁迫还显著提高了常春藤叶片内可溶性糖和可溶性蛋白的含量,说明常春藤对2mmol-L-1液体甲醛胁迫的抗性较强。通过构建2mmol.L-1液体甲醛胁迫2-48h常春藤叶片的正向SSHcDNA文库,分离鉴定常春藤叶片中的甲醛胁迫应答基因并对甲醛胁迫应答基因进行功能聚类,结果说明光合作用和代谢相关基因占的比例最大,表达分析结果证实光合作用和代谢相关基因在2mmol·L-1液体甲醛胁迫的不同阶段被诱导上调表达,这些基因的上调表达可能和甲醛在常春藤叶片内的代谢脱毒有关。此外,参与植物对多种生物和非生物胁迫应答的14—3-3蛋白基因(14—3-3p)也受2mmol·L-1液体甲醛胁迫的强烈诱导,该基因的上调表达可能参与甲醛胁迫下常春藤叶片内可溶性蛋白的合成与抗氧化系统活性的调控作用,是常春藤叶片应答甲醛胁迫的重要基因之一。  相似文献   

3.
以蚕豆为材料,考察气体甲醛(HCHO)胁迫对保卫细胞H2O2积累和叶片气孔导度、开度的影响。结果表明:气体HCHO胁迫增加了叶片中H2O2的积累,荧光显微分析发现在较低浓度(0.20.4μmol·L-1)气体HCHO胁迫下,保卫细胞中增加的H2O2主要分布在细胞质中,高浓度(0.81.6μmol·L-1)气体HCHO胁迫不仅增加保卫细胞质中H2O2的积累,而且显著增加叶绿体中H2O2的含量及积累H2O2的叶绿体数量,这说明在高浓度气体HCHO胁迫下蚕豆保卫细胞中增加的H2O2主要来源于叶绿体和细胞质。保卫细胞中H2O2积累的增加显著降低蚕豆的气孔导度和开度,从而导致蚕豆HCHO吸收效率下降。气体HCHO胁迫下叶片中抗氧化酶活性的变化可能是H2O2积累增加的主要原因,气体HCHO胁迫显著增强叶片中CAT和SOD的活性,但只有低浓度HCHO胁迫诱导叶片POD活性,叶片APX对HCHO胁迫很敏感,低浓度的气体HCHO对叶片APX活性都有显著的抑制作用。  相似文献   

4.
为提高植物对甲醛的吸收和耐受,利用拟南芥CAT的编码区构建植物过表达载体pk2-Prbc S-*T-CAT,在野生型(WT)烟草叶绿体中过量表达CAT产生2个表达量不同的转基因株系(C1、C3)。用10ppm、20ppm和40ppm气体甲醛处理WT和转基因烟草,分析过量表达CAT的转基因烟草对甲醛的吸收效率和耐受性。结果表明,转基因烟草对气体甲醛的吸收量明显高于WT,且随着处理浓度的升高,转基因株系叶片的可溶性总糖、总蛋白质和总叶绿素含量都显著高于WT;转基因株系叶片氧化损伤指标H202、丙二醛(MDA)和羰基化蛋白(PC)的含量都显著低于野生型。转基因烟草(C1)的PM H+-ATPase和氢泵活性在40ppm处理后为WT的3倍和2.5倍,C1的气孔导度为WT的2.67倍。这些结果表明,在烟草中过量表达拟南芥CAT能降低甲醛进入烟草细胞引起的氧化损伤,提高烟草对甲醛的脱毒能力,增强烟草对甲醛的吸收和抗性。揭示气体甲醛胁迫时质膜H+-ATPase和氢泵活性影响叶片气孔的导度,这可能是转基因烟草甲醛吸收效率提高的原因之一。  相似文献   

5.
3种观赏植物对室内甲醛污染的净化及生长生理响应   总被引:2,自引:0,他引:2  
在密封条件下,采取熏蒸法研究了常春藤、绿萝、驱蚊草对不同浓度梯度的甲醛气体胁迫的吸收能力及其生理响应。结果显示:(1)3种植物对室内甲醛气体均有不同程度的吸收能力,其吸收率随室内甲醛气体浓度的升高而逐渐增加,且吸收能力表现为常春藤>驱蚊草>绿萝。(2)与对照相比,随着室内甲醛气体胁迫浓度的增加,驱蚊草、绿萝、常春藤的叶绿素含量先升高再降低,而叶绿素a/b值的变化趋势各有不同。(3)不同浓度甲醛气体胁迫下,3种植物的超氧化物歧化酶(SOD)活性和过氧化物酶(POD)活性均显著升高,并以常春藤的增加量最大(分别为113.21%和120.84%),驱蚊草的增加量最小(分别为69.04%和60.76%);而3种植物的过氧化氢酶(CAT)活性与对照相比显著降低,并以驱蚊草的变化量最大(49.54%),绿萝的变化量最小(14.66%)。(4)驱蚊草、绿萝、常春藤的丙二醛(MDA)含量和脯氨酸含量随着甲醛气体浓度的增加呈升高趋势。综合分析表明,3种室内植物耐受甲醛胁迫的能力存在显著差异,常春藤属于吸收多、耐性强的植物,驱蚊草属于吸收多、耐性弱的植物,而绿萝属于吸收少、耐性强的植物。  相似文献   

6.
本研究考查在2、4和6 mmol·L~(-1)甲醛(HCHO)溶液中处理的‘丹波’黑大豆(Glycine max cv.Tamba)根系对HCHO的吸收与代谢产物。结果表明,在48 h处理期内根系对HCHO的吸收与时间的关系为指数函数。活体根系吸收HCHO对其去除的贡献率分别为30.1%、26.7%和23.0%,显著大于死根系对HCHO的吸附作用,这一结果表明活体根中发生了HCHO代谢作用。碳-13核磁共振(~(13)C-NMR)分析表明,根系吸收的H~(13)CHO首先被氧化为H~(13)COOH;在H~(13)CHO处理0~4 h期间,H~(13)COOH被同化为草酸、甘氨酸、天冬酰胺、谷氨酰胺和丝氨酸,在4~48 h期间,这些有机酸被转化为苹果酸、柠檬酸、异柠檬酸和葡萄糖。4和6 mmol·L~(-1) H~(13)CHO处理2 h的根系中代谢产物种类与2 mmol·L~(-1)处理的相似,但每种代谢产物产量显著提高。  相似文献   

7.
为了研究多胺参与植物应答气体甲醛胁迫的生理特性,以模式植物烟草为实验材料分析了在气体甲醛胁迫下分别采用100μmol/L精胺和200μmol/L亚精胺预处理对烟草叶片甲醛吸收效率、叶绿素含量、过氧化生理指标、抗氧化酶系统活性及甲醛代谢的影响。结果表明:(1)精胺和亚精胺预处理可以显著提高烟草对1、3和5 mg/m~3气体甲醛的吸收效率,且精胺的效果好于亚精胺。(2)在气体甲醛胁迫下,精胺和亚精胺预处理延缓了烟草叶片中叶绿素b降解,且对过氧化氢(Hydrogen peroxide,H_2O_2)和丙二醛(Malondialdehyde,MDA)的积累有抑制作用。此外,精胺和亚精胺预处理不同程度提高了气体甲醛胁迫下过氧化物酶(Peroxidase,POD)、过氧化氢酶(Catalase,CAT)、抗坏血酸过氧化物酶(Ascorbate peroxidase,APX)和超氧化物歧化酶(Superoxide dismutase,SOD)的活性。(3)精胺与亚精胺预处理对烟草代谢气体甲醛没有促进作用。  相似文献   

8.
最近的研究证明在叶绿体内过量表达甲基营养细菌RuMP中固定HCHO的关键酶6-磷酸己酮糖合成酶(HPS)和6-磷酸果糖异构酶(PHI)的融合蛋白HPS-PHI可以在转基因天竺葵中构建一条甲醛光合同化途径从而提高植物对甲醛的同化和脱毒能力。甲醇氧化酶(AOD1)是甲基营养型酵母甲醇代谢途径的第一个关键酶,可催化甲醇氧化为甲醛。在烟草叶绿体中过量表达AOD1或/和HPS-PHI产生过量表达AOD1(AO)、HPS-PHI(AB)、同时过量表达AOD1和HPS-PHI(AA)的转基因烟草。用2和6mmoL/L(13)CH_3OH处理3种转基因烟草和野生型烟草(WT),(13)CH_3OH处理3种转基因烟草和野生型烟草(WT),(13)CNMR分析表明AO植株中积累的H(13)CNMR分析表明AO植株中积累的H(13)COOH最多,[U-(13)COOH最多,[U-(13)C]Gluc和[U-(13)C]Gluc和[U-(13)C]Fruc的生成量在AO和WT间无显著差异,在AA和AB中的产生量显著高于AO和WT,且在AA中的生成量又高于AB,这种差异在6mmol/L(13)C]Fruc的生成量在AO和WT间无显著差异,在AA和AB中的产生量显著高于AO和WT,且在AA中的生成量又高于AB,这种差异在6mmol/L(13)CH_3OH处理植株中比2 mmol/L更为明显。这些结果证实在叶绿体中过表达AOD1增加烟草氧化甲醇为甲酸的能力,同时过量表达AOD1和HPS-PHI在烟草中成功地构建一个甲醇光合同化途径,提高烟草同化甲醇为糖类物质的能力。  相似文献   

9.
甲醛胁迫下四种盆栽植物的生理动态反应   总被引:1,自引:0,他引:1       下载免费PDF全文
选择巢蕨(Neottopteris nidus)、巴西铁(Dralaena fragrans)、虎尾兰(Sansevieria trifasciata)和黑美人(Aglaonema commutatum)4种室内盆栽植物作为典型的试验材料,以15 mg·m-33甲醛分别进行熏蒸处理,测定单位干物质甲醛的吸收量、相对电导率、丙二醛含量和叶绿素含量等,以研究这些植物在甲醛胁迫下的生理动态反应。结果表明:在甲醛胁迫的4 d时间内,巢蕨和巴西铁的单位干物质甲醛吸收量均在第3天达到峰值,而黑美人和虎尾兰则一直在缓慢增加,其中以巢蕨吸收的量最多,巴西铁单位干物质甲醛吸收量最少; 4种植物的相对电导率、丙二醛的含量均随甲醛胁迫时间的增加而增加,以巢蕨的相对电导率最高,虎尾兰最低,但巴西铁的丙二醛的含量最高,巢蕨最低; 4种植物的叶绿素含量均随甲醛胁迫时间的增加而降低,其中黑美人降低幅度最高,虎尾兰最低。  相似文献   

10.
贺辉  彭其安 《广西植物》2019,39(6):737-742
该研究采用密封舱法模拟室内甲醛污染环境(熏蒸箱内甲醛浓度设置为0.1~0.5 mg·m~(-3),熏气时间12 h),对6种常见室内观赏植物进行甲醛熏蒸实验,测定了植物对甲醛的吸收效率、叶面伤害指数及过氧化物酶(POD)等指标。结果表明:这6种常见观赏植物对甲醛均具较好的净化效果,甲醛熏蒸浓度为0.1~0.3 mg·m~(-3),白鹤芋对甲醛的净化效果最好;熏蒸浓度0.5 mg·m~(-3),绿萝和吊兰具有较好的净化和抗逆性能;铁线蕨对甲醛的耐受力较弱,适合作为室内甲醛污染的指示性植物。几种受试植物的POD酶与甲醛吸收率呈显著正相关关系(P0.05),表明植物POD活力变化是受甲醛胁迫后的主要抗逆应答机制之一。  相似文献   

11.
Formaldehyde, one of the most toxic organic compounds, is produced and processed in human cells. The level of human endogenous formaldehyde is maintained at a low concentration (0.01–0.08 mmol L−1 in blood) under physiological conditions, but the concentration increases during ageing (over 65 years old). Clinical trials have shown that urine formaldehyde concentrations are significantly different between elderly Alzheimer’s patients (n=91) and normal elderly volunteers (n=38) (P<0.001). Abnormally high levels of intrinsic formaldehyde lead to dysfunction in cognition such as learning decline and memory loss. Excess extracellular and intracellular formaldehyde could induce metabolic response and abnormal modifications of cellular proteins such as hydroxymethylation and hyperphosphorylation, protein misfolding, nuclear translocation and even cell death. This cellular response called formaldehyde stress is dependent upon the concentration of formaldehyde. Chronic impairments of the brain resulted from formaldehyde stress could be one of the mechanisms involved in the process of senile dementia during ageing.  相似文献   

12.
Formaldehyde fixation   总被引:14,自引:0,他引:14  
  相似文献   

13.
New Formaldehyde Base Disinfectants   总被引:1,自引:0,他引:1       下载免费PDF全文
Preparations of formaldehyde in various organic liquids-ethylene glycol, glycerol, and propylene glycol-serve as effective disinfectants towards microbial vegetative cells and spores. This disinfection is a temperature-dependent process and is manifest when these formaldehyde base disinfectants are dissolved in water. The irritating vapors associated with formaldehyde disinfection are not present in either of these new formaldehyde base disinfectants or in aqueous solutions of them.  相似文献   

14.
15.
Formaldehyde oxidation and methanogenesis   总被引:5,自引:4,他引:1  
Formaldehyde oxidation by cell-free extracts of Methanobacterium thermoautotrophicum was shown to drive methanogenesis from CH3-S-coenzyme M or HCHO under a nonreductive atmosphere of N2. Under N2 when HCHO was the sole source of carbon and reducing equivalents in the reaction, it underwent oxidation and reduction events (disproportionation), the sum of the reactions being 3 HCHO + H2O----CH4 + 2 HCOO - + 2H+. This reaction predicts a CH4/HCHO ratio of 1/3, which is in agreement with the experimental finding of 1/2.9. In extracts of the mesophilic methanogen Methanococcus voltae and the extreme thermophile Methanococcus jannaschii , which exhibited formate dehydrogenase activity, the CH4/HCHO ratio was 1/2. NADPH stimulated methane formation from HCHO under N2. An unidentified, oxygen-labile cofactor, the formaldehyde activation factor, present in boiled-cell extract was discovered. Methanopterin , an oxygen-stable molecule, also substituted for boiled-cell extract.  相似文献   

16.
Summary Formaldehyde is the most commonly used fixative in pathology laboratories. However, due to time pressures, this fixative is often not optimally exploited. the majority of biopsies are only partly fixed when histoprocessing is started, with adverse effects. This paper reports how formaldehyde fixation is improved, by using 1.5 min of microwave irradiation of tissue previously soaked for four hours in the fixation solution. It is argued that this beneficial effect of microwave irradiation can be attributed to the acceleration of the reaction of formaldehyde to the tissue. Formation of free formaldehyde, by the dehydration of methylene glycol present in the tissue when the irradiation starts, is also enhanced. Five different formaldehyde-containing fixatives were evaluated, using five different working protocols. Spleen was taken as a suitable tissue for these tests. The technique described leads to uniform microscopical results. It is a simple method and is suitable for use in routine laboratories.  相似文献   

17.
18.
Subchronic administration of semicarbazide in the experiment with the rats was used to reduce the formaldehyde level in the organism in order to reveal the interaction between formaldehyde metabolism and biochemical parameters, which define the oxidant-antioxidant system condition and NO metabolism. It has been found that under semicarbazide impact the generation of free radicals, ROS, nitrite and nitrate were enhanced while aldehydes level was reduced that resulted from not only semicarbazide effect like the aldehydes acceptor, but the formaldehyde synthesis slowdown and acceleration of its transformation into format as well. We suppose that formaldehyde plays certain role in the development of connective tissue pathology.  相似文献   

19.
For critical histological investigations, tissue fixation is sometimes carried out in formaldehyde freshly prepared from paraformaldehyde by heating. The purity of formaldehyde produced in this way is superior to that of commercial stock solutions. We studied the stability of freshly prepared formaldehyde solutions by determination of pH and titration of acid, which reflect the formation of formic acid. It was found that very small amounts of acid are produced during the heating of paraformaldehyde. Prolonged heating or storage of freshly prepared formaldehyde for up to 8 days did not significantly increase the amount of acid. It was also found that heating of the paraformaldehyde is not necessary, since depolymerization may take place at room temperature.

We conclude that formaldehyde prepared from paraformaldehyde remains stable for considerable periods of time, and it is therefore unnecessary to prepare it immediately prior to fixation. Also, in many cases, buffering of the fixative may be omitted, since only minor changes in the pH occur during fixation.  相似文献   

20.
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