297 research outputs found

    Ethylene Signaling Controls Fast Oxygen Sensing in Plants

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    When plants are submerged by water they suffer from hypoxia. Although it has long been known that ethylene accumulates in submerged plants, its role in plant tolerance to hypoxia remained elusive. Recently, Hartman et al. described a mechanism that explains the role of ethylene in oxygen sensing and signaling

    Physiological and genetic control of anthocyanin pigmentation in different species

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    Koes, R.E. [Promotor]Quattrocchio, F. [Copromotor]Perata, P. [Copromotor

    RETURN DAN RISIKO SAHAM PADA PERUSAHAAN PERATA LABA DAN BUKAN PERATA LABA

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    Perataan laba merupakan praktik yang umum dilakukan oleh manajer perusahaan untuk mengurangi fluktuasi laba, yang diharapkan memiliki efek menguntungkan bagi evaluasi kinerja manajemen. Beberapa peneliti percaya bahwa investor memiliki lebih banyak kecenderungan untuk berinvestasi di perusahaan yang menerapkan perataan laba. Investor percaya bahwa perusahaan halus memiliki return yang berbeda dan risiko investasi. Beberapa penelitian membuktikan tentang return yang berbeda dan risiko investasi antara perusahaan perata dan bukan perata laba. Studi lainnya menyatakan bahwa tidak ada perbedaan antara perusahaan perata dan bukan perata laba. Penelitian ini mencoba untuk menguji perbedaan risiko investasi dan return antara perusahaan manufaktur perata dan bukan perata laba yang terdaftar di Bursa Efek Indonesia pada tahun 2009-2011. Perusahaan-perusahaan diklasifikasikan dengan Indeks Eckel dan pendapatan berdasarkan pendapatan operasional, laba sebelum pajak, dan laba setelah pajak. Studi ini menunjukkan bahwa tidak ada perbedaan return investasi antara perusahaan perata dan bukan perata laba. Namun, ada perbedaan dalam risiko investasi antara perusahaan perata dan bukan perata labaKata kunci: Return, Risiko, Perata laba, Beta Income smoothing is a common practice by corporate managers to reduce fluctuations in earnings, which are expected to have beneficial effects for management performance evaluation. Some researchers believe that investors have much more tendency to invest in companies that apply income smoothing. Investors believe that smoother companies have different return and risk investment.  Some studies prove about different return and risk investment between the smoother and non-smoother companies. On the other hand, the rest studies state that there is no difference between smoother and non-smoother companies. This study tries to examine the difference of investment risk and return between smoother and non-smoother manufacturing companies which is listed in Indonesian Stock Exchange in 2009-2011. Those companies are classified with Eckel Index and income based on operating income, earnings before tax, and earnings after tax. This study shows that there is no difference in investment return between smoother and non-smoother companies. Yet, there is a difference in investment risk between smoother and non-smoother companies.</p

    The Oxidative Paradox in Low Oxygen Stress in Plants

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    Reactive oxygen species (ROS) are part of aerobic environments, and variations in the availability of oxygen (O2) in the environment can lead to altered ROS levels. In plants, the O2 sensing machinery guides the molecular response to low O2, regulating a subset of genes involved in metabolic adaptations to hypoxia, including proteins involved in ROS homeostasis and acclimation. In addition, nitric oxide (NO) participates in signaling events that modulate the low O2 stress response. In this review, we summarize recent findings that highlight the roles of ROS and NO under environmentally or developmentally defined low O2 conditions. We conclude that ROS and NO are emerging regulators during low O2 signalling and key molecules in plant adaptation to flooding conditions

    Fruit colour and novel mechanisms of genetic regulation of pigment production in tomato fruits

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    Fruit colour represents a genetic trait with ecological and nutritional value. Plants mainly use colour to attract animals and favour seed dispersion. Thus, in many species, fruit colour coevolved with frugivories and their preferences. Environmental factors, however, represented other adaptive forces and further diversification was driven by domestication. All these factors cooperated in the evolution of tomato fruit, one of the most important in human nutrition. Tomato phylogenetic history showed two main steps in colour evolution: the change from green-chlorophyll to red-carotenoid pericarp, and the loss of the anthocyanic pigmentation. These events likely occurred with the onset of domestication. Then spontaneous mutations repeatedly occurred in carotenoid and phenylpropanoid pathways, leading to colour variants which often were propagated. Introgression breeding further enriched the panel of pigmentation patterns. In recent decades, the genetic determinants underneath tomato colours were identified. Novel evidence indicates that key regulatory and biosynthetic genes undergo mechanisms of gene expression regulation that are much more complex than what was imagined before: post-transcriptional mechanisms, with RNA splicing among the most common, indeed play crucial roles to fine-tune the expression of this trait in fruits and offer new substrate for the rise of genetic variables, thus providing further evolutionary flexibility to the character

    allow communication within and between organisms

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    Plant microRNAs (miRNAs) are small regulatory RNAs that are encoded by endogenous miRNA genes and regulate gene expression through gene silencing, by inducing degradation of their target messenger RNA or by inhibiting its translation. Some miRNAs are mobile molecules inside the plant, and increasing experimental evidence has demonstrated that miRNAs represent molecules that are exchanged between plants, their pathogens, and parasitic plants. It has also been shown that miRNAs are secreted into the external growing medium and that these miRNAs regulate gene expression and the phenotype of nearby receiving plants, thus defining a new concept in plant communication. However, the mechanism of miRNA secretion and uptake by plant cells still needs to be elucidated
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