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1.
The active ingredient of ‘Lovozal’ (fenazaflor) is hydrolysed in solution to 5,6-dichloro-2-trifluoromethyl-benzimidazole (DTFB). Rat liver mitochondria were uncoupled by fenazaflor after a lag phase, while uncoupling by DTFB was immediate, and a similar situation occurred with mitochondria isolated from Tetranychus telarius L. (This is the first report of isolation of mite mitochondria.) Since both compounds ultimately have the same uncoupling activity, it is likely that fenazaflor exerts its effect only after hydrolysis to DTFB. Living mites showed a stimulation of respiration of 70% on addition of either fenazaflor or DTFB before death occurred, suggesting that the acaricidal effect of fenazaflor is due to uncoupling of oxidative phosphorylation after hydrolysis to DTFB.  相似文献   

2.
β-Pinene uncouples oxidative phosphorylation and inhibits respiration in isolated rat liver mitochondria. The uncoupling effects are observed at lower concentrations (100 to 200 μM) than the inhibition of respiration (400 μM). At low concentrations, the effects observed could be explained by an increase of the passive permeability of the mitochondrial membrane produced by the terpene. Higher concentrations seemed to inhibit respiration through an effect on the electron transport chain. At the highest concentrations tested (600 to 1200 μM), β-pinene seemed to produce a partial resealing of the mitochondrial membrane. All effects can be explained by the interaction of β-pinene with the mitochondrial membrane. Other hydrophobic molecules tested do not show the effects of β-pinene or limonene on mitochondria.  相似文献   

3.
The pesticide chlordimeform [N′-(4-chloro-o-tolyl)-N,N-dimethylformamidine] at 0.04 μmoles/mg protein uncouples 50% of respiratory-chain phosphorylation of rat liver mitochondria. This uncoupling activity depends on mitochondrial protein concentration and can be reversed either by the addition of bovine serum albumin or by washing. The normal inhibition of state 3 respiration by oligomycin and atractylate is completely reversed by chlordimeform. Uncoupling concentrations of chlordimeform elicit high adenosine triphosphatase activity. This activity is blocked by the above inhibitors of mitochondrial energy-transfer reactions. Evidence is presented which shows that unprotonated chlordimeform is the form effective in uncoupling. It is concluded that chlordimeform is an uncoupling agent with a potency and site of action close to but probably not identical to that of the classical uncoupler 2,4-dinitrophenol.  相似文献   

4.
The uncoupling concentrations which caused a 50% reduction in the ADP/0 ratios for rat liver mitochondria was found to be 4.29 nM per mg of mitochrondrial protein for TFM (3-trifluoromethyl-4-nitrophenol), and 11.15 nM for DNP (2,4-dinitrophenol). The increased oxygen consumption of the mitochondrial preparation is characteristic of uncoupling effects and need not be attributed to the action of detoxication enzyme systems. Interference or synergism due to impurities of the commercial preparation of TFM may affect its differential toxicity characteristics in the field.  相似文献   

5.
Carboxin (5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxanilide) was tested for its effect on the activities of mitochondria from several fungi, pinto beans and rat liver. Succinate oxidation by mitochondria from the sensitive fungus Ustilago maydis was inhibited by low concentrations of carboxin, the Ki being 0.32 μM. The inhibition was of a noncompetitive nature. Succinate oxidation was also inhibited in the mitochondria from other sources but not to the extent as in those from U. maydis. Carboxin had little effect on the oxidation of reduced nicotinamide adenine dinucleotide. The dioxide of carboxin, oxycarboxin, was not as effective in inhibiting succinate oxidation as was carboxin, but was more effective than the monoxide. Carboxin did not appear to uncouple oxidative phosphorylation in the presence of succinate in tightly coupled rat liver mitochondria but did decrease the respiratory control ratio. Carboxin was ineffective in releasing oligomycin inhibition in coupled rat liver mitochondria while dinitrophenol and salicylanilide were effective in this respect. It is believed that carboxin inhibits mitochondrial respiration at or close to the site of succinate oxidation and does not greatly affect the remaining portion of the electron transport system or the coupled phosphorylation reactions.  相似文献   

6.
Chloroneb (1,4-dichloro-2,5-dimethoxybenzene) is a fungicide with moderate systemic properties and selective activity toward certain fungi (e.g., Phytophthora, Pythium, Botrytis, Mucor). Although the compound is metabolized by some fungi to the toxic oxidation products DCMP (2,5-dichloro-4-methoxyphenol) and DCHQ (2,5-dichlorohydroquinone) the fungitoxic principle is chloroneb per se. It causes a lysis of the inner mitochondrial membrane of sensitive fungi, attacks the nuclear membrane and also other membranes at higher doses. Oxygen consumption by isolated mitochondria slowly decreases, but the respiratory control quotient remains nearly constant. No specific uncoupling activity or inhibition of the respiratory chain could be detected. Chloroneb is bound to the mitochondrial membrane in sensitive organisms, and a good correlation exists between binding capacity, damage to mitochondrial structure and function, and growth inhibitory effects. DCMP has a nearly identical effect, but some additional uncoupling activity whereas DCHQ is different in its mechanism of action. A comparison of a chloroneb-sensitive strain of Mucor mucedo and a resistant strain with respect to the amino acid composition of their mitochondrial membranes demonstrated a significantly diminished content of tyrosine in the resistant strain, which may be associated with the decreased binding capacity for chloroneb. Although the reason for mitochondrial destruction is not yet elucidated, counteracting effects of piperonylbutoxide and α-tocopherol acetate suggest that a radical mechanism may be involved.  相似文献   

7.
Etridiazole (5-ethoxy-3(trichloromethyl)-1,2,4-thiadiazole) is a fungicide primarily effective against fungi of the Oomycete group. After addition of the compound to the medium, growth of Mucor mucedo was impaired almost immediately. Oxygen uptake of the mycelia decreased only slightly at growth-inhibiting concentrations. Respiration of isolated mitochondria of Mucor was inhibited about 50% by high concentrations of the fungicide, while the respiratory control quotient remained constant. In contrast, rat liver mitochondria were not very sensitive to etridiazole. Etridiazole stimulates the hydrolysis of membrane-bound phospholipids to free fatty acids and lysophosphatides in isolated mitochondria of Mucor. Procaine, a well-known inhibitor of phospholipases, acts as an antidote for etridiazole in growth tests as well as in the hydrolysis of phosphatidylcholine by isolated mitochondria. Calcium ions in millimolar concentrations act like procaine. Therefore, it was assumed that the fungistatic effect of etridiazole was mainly caused by an activation of phospholipases in the mitochondrial membranes. Moreover, under the influence of etridiazole, a lipid peroxidation of membranes is observed. Tocopherol acts as an antidote. This could be the primary toxic effect in the mechanism of action of this fungicide. The enzymes involved are not yet identified.  相似文献   

8.
Meloidogyne ethiopica is one of the most important plant-parasitic nematodes affecting vines in Chile and is very aggressive and difficult to control. This study evaluated 16 strains of rhizobacteria, originally isolated from roots of grapevines, for their effects on parasitism and nematode damage to potted vine plants. The antagonistic effect of rhizobacteria was assessed by treating 2-month-old plants of cv. Chardonnay in 3-l pots with a suspension containing 1?×?106?cfu?ml?1 of the bacteria and 1,000 nematode eggs. After 6?months of growth, the plants were cut and root and canopy weights, nematode populations and root damage determined. The effect of rhizobacterial culture filtrate on hatching of nematode eggs was also assessed in vitro. Seven strains of rhizobacteria proved effective in inhibiting damage or reproduction of the nematode. These were strains of Serratia marcescens, Comamonas acidovorans, Pantoea agglomerans, Sphingobacterium spiritivorum, Bacillus mycoides, Alcaligenes piechaudii and Serratia plymuthica. A further three strains, of Bacillus megaterium, P. agglomerans and Pseudomonas savastanoi, significantly increased root weight, but did not decrease nematode damage or population density. The supernatant of all strains significantly decreased hatching of juvenile nematodes after 24?h of immersion, with isolates of P. putida and B. megaterium being the most effective.  相似文献   

9.
The effects of phosphine on electron transport and on some partial reactions of oxidative phosphorylation of mitochondria from mouse liver, housefly flight muscles and granary weevils has been studied. Phosphine was a strong inhibitor of respiration of mitochondria in the “active” state (state 3), uncoupled state, and ion-pumping state on glutamate, pyruvate plus malate, succinate, α-glycerophosphate, and ascorbate-cytochrome c as substrates. Respiration of mitochondria in state 3 was completely inhibited by about 250 μM phosphine. By contrast, the respiration of mitochondria in state 4 was much less sensitive. This inhibition could not be released by uncouplers suggesting that it is due to a direct effect on electron transport. Only site III was inhibited to any significant extent. Kinetic studies show that the inhibition was noncompetitive with Ki ranging from 1.6×10?5 to 7.2×10?5 depending on the source and purity of cytochrome oxidase. The inhibition of site III was also more pronounced in sonicated particles than in intact mitochrondria. The significance of this is discussed in relation to membrane sideness and topology of the components of the respiratory chain.Phosphine was unable to activate the “latent” ATPase nor did it have any inhibition of the Mg2+-simulated ATPase and only high levels (1.1 mM) showed modest inhibition (41%) of uncoupler-stimulated ATPase. Phosphine had no effect on the ATP-Pi exchange and on the ATP-ADP exchange reaction at concentrations causing strong respiratory inhibition.  相似文献   

10.
Long-term experiments with dactyl cells of Nitella flexilis showed that the herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) at a concentration of 1 × 10?5M affected not only O2 evolution in the light but also O2 uptake in the dark. The inhibition of O2 production was transitory, but dark respiration did not recover. DCMU induced the formation of giant mitochondria which disappeared before cell death. It was concluded that the algicidic effect of 1 × 10?5M DCMU on N. flexilis, but not necessarily the elongation of mitochondria, was due to the inhibition of mitochondrial respiration and not of photosynthesis.  相似文献   

11.
sec-Butylamine at 5 mM inhibited the oxidation of pyruvate by mitochondria isolated from hyphae of Penicillium digitalum, but had little effect on the oxidation of citrate, isocitrate, succinate, malate, acetyl-coenzyme A, or reduced nicotinamide adenine dinucleotide. sec-Butylamine did not interfere with oxidative phosphorylation, as evidenced by similar PO ratios in treated and control mitochondria. The pyruvate dehydrogenase complex (EC 1.2.4.1) isolated from young hyphae of P. digitatum was inhibited strongly by 20 mM sec-butylamine, whereas other tricarboxylic acid cycle enzymes were only slightly affected at most. Inhibition of the pyruvate dehydrogenase complex by sec-butylamine was competitive with respect to pyruvate. The Ki for sec-butylamine in the reaction was 1.38 × 10?2M, and the Km for pyruvate was 2.28 × 10?4M. These observations and other evidence derived from studies with intact hyphae support the hypothesis that the pyruvate dehydrogenase complex is the primary site of the fungistatic action of sec-butylamine.  相似文献   

12.
三种赤眼蜂对灰白蚕蛾的卵龄选择   总被引：2，自引：2，他引：0  
灰白蚕蛾Ocinara varia.是近年来华南地区为害较严重的园林害虫,为筛选有效防治灰白蚕蛾的赤眼蜂种,在室内条件下比较了短管赤眼蜂Trichogramma pretiosum、松毛虫赤眼蜂T.dendroli-mi和暗黑赤眼蜂T.euproctidis对不同卵龄灰白蚕蛾卵的寄生能力和适应能力.结果显示,随寄主卵龄的增加松毛虫赤眼蜂和暗黑赤眼蜂寄生卵数均呈下降趋势,且都在灰白蚕蛾卵龄为6h的卵上寄生卵数最多,分别为15.90粒/雌和12.20粒/雌;而短管赤眼蜂的寄生卵数随寄主卵龄的增加呈先上升后下降趋势,在卵龄为24 h时达最高,为8.25粒/雌;在各卵龄段,松毛虫赤眼蜂的寄生卵数均比其它2种蜂多;当寄主卵龄超过72 h时,3种赤眼蜂的寄生卵数均显著下降.3种赤眼蜂在寄生卵龄为6h的寄生卵上羽化率最高,当卵龄超过72 h时,其羽化率均显著下降.松毛虫赤眼蜂和暗黑赤眼蜂对6h卵龄的灰白蚕蛾卵致死能力最强,而短管赤眼蜂对24 h卵龄的灰白蚕蛾卵致死能力最强.综合分析表明,松毛虫赤眼蜂在灰白蚕蛾卵上的寄生能力和适应能力最好,是灰白蚕蛾的有效天敌.  相似文献   

13.
The results showed that the essential oil from Piper sarmentosum has strong antifeedant and toxicity effects on Brontispa longissima. The best antifeedant and contact toxicity effects were observed in the 1st-2nd instar larvae. The essential oil also displayed a notable fumigation effect on the eggs and pupae of B. longissima. It took the control-treated insects 43.34 d to complete one generation, while the insects treated with 2000 mg/L essential oil needed 73.58 d. The essential oil was analyzed by gas chromatography/mass spectrometry and 41 components were identified. Myristicin (65.22%) and trans-caryophyllene (13.89%) were the major components. Myristicin exhibited strong antifeedant and contact toxicity effects on both the 3rd instar larvae and the imagoes of B. longissima, when it showed a significant fumigation effect on the eggs and pupae of B. longissima. Another P. sarmentosum essential oil and myristicin all showed a strong inhibiting effect on the growth and development of B. longissima along with the activity of AChE, CarE, GSTs and Na+, K+-ATPase in B. longissima larvae.  相似文献   

14.
This paper describes the effect of the oxygen analog of ronnel (OAR) on the respiration of brain mitochondria from 4- and 16-day-old and 2- and 18-month-old rats. The oxygen analog of ronnel seems to be an uncoupler of oxidative phosphorylation in brain mitochondria derived from rats at all ages investigated. The results reported here suggest that the sensitivity of mitochondria to the uncoupling effect of OAR is an age-dependent phenomenon. Most sensitive were mitochondria isolated from brains of 18-month-old animals, while the most resistant were mitochondria derived from newborn rats (4 days old), as compared with young adult rats (2 months old). The relation between membrane structure and insecticide action is discussed.  相似文献   

15.
The effects of lufenuron, a chitin synthesis inhibitor, on oogenesis of Rhodnius prolixus were evaluated. Lufenuron-treated females lay eggs that are pink, but change color with time, acquiring a gray color. The eggs are abnormal in shape and become dehydrated. The percentage of eggs that hatch is decreased compared with the eggs from non-treated females. Digestion of ovaries with KOH yielded an insoluble white material, which was identified as chitin based on infrared and proton NMR spectral analyses along with standard commercial chitin. Glucosamine was detected by HPLC as the major product of acid hydrolysis of the KOH-insoluble material prepared from the ovary. Furthermore, presence of chitin in ovary was confirmed through fluorescent microscopy technique using a wheat germ agglutinin probe and by re-treatment with Streptomyces griseus chitinase that resulted in reduction of chitin-derived fluorescence. Micrographs of ovaries, from animals treated with lufenuron, showed some space between the follicular epithelium and the oocyte membrane. The in vivo incorporation of radioactive N-acetylglucosamine into chitin was inhibited by the presence of lufenuron. These data suggest that chitin present in ovaries of R. prolixus is an important component of the eggs and is involved in oogenesis. Exposure to lufenuron reduces the size of oocytes, number of chorionated oocytes, and also the incorporation of N-acetylglucosamine into chitin in the ovaries. In addition, lufenuron-induced oosorption, decreased the number of eggs laid, modified egg shape and color and reduced the viability of the eggs. Therefore, chitin or chitin-like component of ovaries may be considered as a new target for controlling R. prolixus populations.  相似文献   

16.
土壤中南方根结线虫的实时荧光PCR检测和定量   总被引：3，自引：2，他引：1  
为了准确测定土壤中南方根结线虫Meloidogyne incognita的群体密度,根据序列特异性扩增区标记设计了南方根结线虫特异性引物和TaqMan探针,分别建立了卵和2龄幼虫的实时荧光PCR定量检测体系,并将该检测体系与显微镜计数法进行了比较.结果表明,引物Mi-F/R及探针Mi-probe对南方根结线虫具有高度特异性,建立的标准曲线循环阈值与卵和2龄幼虫数量的对数值之间具有良好的线性关系,相关系数分别为0.9771和0.9853,扩增效率均为90％,检测灵敏度为10-1个卵及10-3条2龄幼虫;对10个田间土壤样本的检测显示,实时荧光PCR定量检测与显微镜计数法测定的南方根结线虫卵和2龄幼虫数量呈显著正相关,且两种方法对2龄幼虫的测定结果无显著差异.  相似文献   

17.
A microsomal malathion carboxylesterase present in Triatoma infestans eggs was active from the first day of embryonic development. This microsomal egg malathionase (MEM) showed a unique band in polyacrilamide gel electrophoresis (PAGE) when malathion was used as substrate. In vivo metabolism of [14C]malathion during all embryonic development showed a 10% degradation due to carboxylesterases. The in vitro evaluation of the same metabolic pathway catalyzed by the microsomal fraction of T. infestans eggs showed partial inhibition by paraoxon. α- and β-malathion monoacids were identified as the main metabolites of the in vivo and in vitro metabolic pathways. The carboxylesterase band that appeared in PAGE (MEM) from the first day of embryonic development could be the main cause of malathion tolerance in T. infestans eggs.  相似文献   

18.
Trichogramma platneri Nagarkatti (Hymenoptera: Trichogrammatidae) was recently introduced into Israel to improve the control of two lepidopterous pests,Boarmia selenaria (Schiffermiiller) andCryptoblabes gnidiella (Millière). Laboratory tests showed thatT. platneri attacks the eggs of both species. A method of freezing the eggs of the host,Ephestia cautella (Walker), at -20°C and gradual defrosting, used in the large laboratory breedings of the parasites, is described briefly. In laboratory tests 68.5% of the frozenE. cautella eggs, after 2 months of storage, were parasitized, compared with 70.3% of the fresh eggs.  相似文献   

19.
为明确西花蓟马Frankliniella occidentalis和豆大蓟马Megalurothrips usitatu共存时的生殖竞争,采用叶盘法测定了孤雌生殖方式下和两性生殖方式下,接入不同数量西花蓟马雌、雄成虫后,豆大蓟马日产卵量和总产卵量;接入不同数量豆大蓟马雌、雄成虫后,西花蓟马的日产卵量和总产卵量,明确了2种蓟马成虫数量和性别对彼此日产卵量和总产卵量的影响。在豆大蓟马孤雌生殖方式下,1头西花蓟马雌成虫即可使其日产卵量和总产卵量显著降低,由8.8粒和61.6粒分别下降至7.5粒和52.4粒,而1头西花蓟马雄成虫对其产卵量无显著影响;在豆大蓟马两性生殖方式下,1头西花蓟马雌成虫同样可显著降低其日产卵量和总产卵量,由6.6粒和46.2粒分别下降至5.2粒和36.6粒,1头西花蓟马雄成虫也可显著降低其产卵量,分别下降至5.9粒和41.4粒;西花蓟马雌成虫对2种生殖方式下豆大蓟马产卵量的影响均显著或极显著大于雄成虫。在西花蓟马孤雌生殖方式下,1头豆大蓟马雌成虫和雄成虫即可显著降低其产卵量,日产卵量由6.8粒均下降至6.1粒,总产卵量由47.4粒分别下降至43.0粒和42.6粒;在西花蓟马两性生殖方式下,1头豆大蓟马雌成虫同样可显著降低西花蓟马的日产卵量和总产卵量,分别由6.1粒和43.0粒下降至4.3粒和30.0粒,但2头豆大蓟马雄成虫才可使其产卵量显著降低;豆大蓟马雌成虫对西花蓟马2种生殖方式下产卵量的影响大于雄成虫。无论是否受到干扰,豆大蓟马2种生殖方式下的日产卵量和总产卵量均高于西花蓟马。表明在西花蓟马与豆大蓟马的生殖竞争中,由于豆大蓟马的繁殖力较高,在竞争中占据优势地位。  相似文献   

20.
Laboratory tests showed that a 2% neem (Azadirachta indica A. Juss) seed kernel suspension (NSKS) in water sprayed onSpodoptera litura (F.) eggs before or after parasitization did not adversely affect the emergence of the egg parasiteTelenomus remus Nixon. When sprayed on eggs before parasitization, the treatment did not repel the parasite. The treatment accelerated the development of the parasite but significantly reduced the longevity of its adult. When parasitized eggs were treated, NSKS significantly increased the adult parasite longevity. Thus, a schedule of NSKS sprays can be integrated withT. remus for the control of the tobacco caterpillar,S. litura, in tobacco nurseries.  相似文献   

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