The Effect of CCC and Amo-1618 on Growth, Catalase, Peroxidase and Indoleacetic Acid Oxidase Activity of Young Barley Seedlings

Barley seedlings were grown in darkness on filter paper saturated with phosphate buffer or CCC and Amo-1618 buffered solutions. The effects of CCC and Amo-1618 on growth, catalase, peroxidase and lAA-oxidase were studied on coleoptile and primary leaves. Both growth-retarding chemicals cause an inhibition of growth, Amo-1618 being more effective than CCC. They have no effect on catalase activity. Increasing concentrations of CCC and Amo-1618 progressively stimulate peroxidase and IAA-oxidase activities (Amo-1618 more than CCC). The enzymatic activity in short-treated plants is higher than in the corresponding control plants of the same height. It is proposed that CCC and Amo-1618 exert their effect on the growth of barley by acting on auxin catabolism.     

Effects of Seselin and Coumarin on Growth, Indoleacetic Acid Oxidase, and Peroxidase, with Special Reference to Cucumber (Cucumis sativa L.) Radicles

Seselin, a natural coumarin derivative isolated from citrus roots, inhibited radicle growth in seedlings of cucumber (Cucumis sativa), lettuce (Lactuca sativum), radish (Raphanus sativus), and wheat (Triticum aestivum) grown in the dark. Coumarin similarly inhibited radicle growth of cucumber seedlings. Growth retardation of the cucumber radicles was accompanied by an increased activity of peroxidase and indole-3-acetic acid oxidase. Both compounds antagonized indole-3-acetic acid-induced growth of wheat coleoptiles, whereas coumarin was much less effective than seselin in antagonizing gibberellic acid-induced release of reducing sugars from barley endosperm. It is suggested that seselin plays an important role in the regulation of root growth, and that it is the indole-3-acetic acid oxidase cofactor previously detected in citrus roots.     

Some Characteristics and Inhibitors of Indoleacetic Acid Oxidase from Tissue 2

Extracts from tissue cultures of crown-gall from Parthenocissuscatalysed the destruction of indoleacetic acid in vitro withoptimum activity at pH 4·5. The presence of two co-factors,Mn⁺⁺ and 2,4-dichlorophenol, was necessary for this activity,which was found to be strictly aerobic. Chlorogenic acid, caffeic acid, scopoletin, ferulic acid, andgibberellic acid markedly inhibited IAA-destruction. Chlorogenicacid inhibition was reversed by the addition of H₂O₂. Chlorogenicacid was not oxidized by the IAA-destroying system and did notbehave as a competitive inhibitor. The IAA-oxidase extract manifested peroxidase and phenolaseactivity with catechol and pyrogallol as substrates. However,this activity was greater at pH 7·0 than at the optimumfor IAA-oxidase activity, pH 4·5. Further evidence ofthe existence of these two enzymes in the intact tissue wasdemonstrated by histochemical studies. In tissue slices, peroxidaseactivity was very high and widely distributed while phenolaseactivity was low and restricted to localized centres of thetissue.     

光叶楮扦插生根的吲哚乙酸氧化酶、多酚氧化酶、过氧化物酶活性变化研究

对光叶楮扦插生根过程中吲哚乙酸氧化酶（IAAO）、多酚氧化酶（PPO）、过氧化物酶（POD）3种酶进行了动态跟踪分析。结果表明：IAAO活性在扦插初期逐渐上升,第10d上升到高峰,之后下降再上升,第30d达到新高峰,然后迅速下降;前25d POD活性变化规律与IAAO相似,但30d以后活性一直上升;PPO活性在扦插前期缓慢上升,第20d上升到了最高点,此后变化不大。还研究了IAAO、PPO、POD与不定根的发生和发展关系,认为光叶楮扦插生根可分为愈伤组织形成期、根诱导期和根的伸长期3个阶段,愈伤组织形成期3种酶活性都呈上升趋势,根诱导期IAAO和POD的活性达到高峰;而根伸长期IAAO和POD活性下降,PPO活性上升。     

Effects of Some Inhibitors of Nucleic Acid and Protein Synthesis on the Development of Amine Oxidase in Germinating Pea Cotyledons

The germination of pea seed was accompanied by a rapid increase of amine oxidase (E.C. 1.4.3.6.) in the cotyledon and over half the increase was ascribable to the presence of axial tissue. The presence of actinomycin D, 6-methylpurine and cycloheximide in the early period of soaking inhibited markedly the increase in amine oxidase activity. However, actinomycin D and cycloheximide had little effect on the enzyme development when added after one day and 2 days of germination respectively. The amine oxidase development was also inhibited by dl -p-fluorophenylalanine, 5-methyltryptophan, chloramphenicol and phenylthiourea.     

Effect of Indoleacetic Acid and Related Indoles on Lactobacillus sp. Strain 11201 Growth, Indoleacetic Acid Catabolism, and 3-Methylindole Formation

A study was conducted to determine the activity of the 3-methylindole (3MI)-forming enzyme in Lactobacillus sp. strain 11201. Cells were incubated anaerobically with 17 different indolic and aromatic compounds. Indoleacetic acid (IAA), 5-hydroxyindoleacetic acid, 5-methoxy-3-indoleacetic acid, indole-3-pyruvate, or indole-3-propionic acid induced 3MI-forming activity. The highest total enzyme activity induced by IAA was observed in cells incubated with an initial concentration of 1.14 mM IAA. Peak activity of the 3MI-forming enzyme occurred 4 h after bacteria were incubated with either 0.114 or 1.14 mM IAA. Enzyme activity peaked earlier (2 h) and disappeared more rapidly at 5.7 mM IAA than at other concentrations of IAA. The effects of IAA and 3MI on the growth of Lactobacillus sp. strain 11201 and formation of 3MI from IAA also were determined. Bacterial growth and 3MI formation from IAA were reduced in medium containing exogenous 3MI. The growth depression observed in medium containing 5.7 mM IAA appears to be due to the toxicity of 3MI rather than IAA. The formation of 3MI in this ruminal Lactobacillus sp. is mediated by an inducible enzyme, and as 3MI accumulates, bacterial growth and rates of 3MI formation from IAA are reduced.     

Activities of Indoleacetic Acid Oxidase and Peroxidase in Ripening Apple Delicious Fruits

Peroxidase was extracted from the apple (Delicious) fruit and the apple stalk during the various stages of ripening. Activities of peroxidase and IAA oxidase of fruits are different.The activities of peroxidase and IAA oxidase in the apple stalk are much higher than that in the apple fruits. Gel electrophoresis revealed that the number of isozymic bands of peroxidase in the stalk (7–9 bands) were more than that in the fruit (6 bands). It is inferred that peroxidase in apple stalk might play a more important role in IAA and some other inhibitors oxidized before then went into the fruits.     

The Relationship of Indole-3-Acetic Acid Content and Growth of Crown-Gall Tumor Tissues of Tobacco in Culture

We have measured the content of the auxin, indole-3-acetic acid (IAA), in a cloned, crown-gall teratoma line of Nicotiana tabacum L. cv. 'Turkish' by a highly specific and sensitive radioimmunoassay. This tissue line, which does not require auxin for continuous growth in culture, exhibits two phases of growth. During the first phase, which lasts about two weeks after subculturing, growth is exponential on a fresh weight basis and the content of IAA is about 10⁻⁷–10⁻⁶ mol. kg⁻¹, but variable. During the second phase, growth rate declines gradually and the IAA content of the tissue drops dramatically; however, this drop does not result from a net loss of auxin by the tissue. The rate of growth during the exponential phase was not correlated with the IAA content of the tissue, but was strongly correlated with the IAA content of the inoculum. We found that rapidly growing leaves of Turkish tobacco have roughly the same IAA content as cultured teratoma tissues. Moreover, both tissues exhibited a similar relationship between auxin content expressed per leaf or per tissue explant and growth. These findings do not support the hypothesis that the autonomous growth of plant tumors results from an abnormally high content of auxin in the tissue.     

In Vitro Effects of Cognitives and Nootropics on Mitochondrial Respiration and Monoamine Oxidase Activity

Impairment of mitochondrial metabolism, particularly the electron transport chain (ETC), as well as increased oxidative stress might play a significant role in pathogenesis of Alzheimer’s disease (AD). Some effects of drugs used for symptomatic AD treatment may be related to their direct action on mitochondrial function. In vitro effects of pharmacologically different cognitives (galantamine, donepezil, rivastigmine, 7-MEOTA, memantine) and nootropic drugs (latrepirdine, piracetam) were investigated on selected mitochondrial parameters: activities of ETC complexes I, II + III, and IV, citrate synthase, monoamine oxidase (MAO), oxygen consumption rate, and hydrogen peroxide production of pig brain mitochondria. Complex I activity was decreased by galantamine, donepezil, and memantine; complex II + III activity was increased by galantamine. None of the tested drugs caused significant changes in the rate of mitochondrial oxygen consumption, even at high concentrations. Except galantamine, all tested drugs were selective MAO-A inhibitors. Latrepirdine, donepezil, and 7-MEOTA were found to be the most potent MAO-A inhibitors. Succinate-induced mitochondrial hydrogen peroxide production was not significantly affected by the drugs tested. The direct effect of cognitives and nootropics used in the treatment of AD on mitochondrial respiration is relatively small. The safest drugs in terms of disturbing mitochondrial function appear to be piracetam and rivastigmine. The MAO-A inhibition by cognitives and nootropics may also participate in mitochondrial neuroprotection. The results support the future research aimed at measuring the effects of currently used drugs or newly synthesized drugs on mitochondrial functioning in order to understand their mechanism of action.