An in Vitro System from Maize Seedlings for Tryptophan-Independent Indole-3-Acetic Acid Biosynthesis1

The enzymatic synthesis of indole-3-acetic acid (IAA) from indole by an in vitro preparation from maize (Zea mays L.) that does not use tryptophan (Trp) as an intermediate is described. Light-grown seedlings of normal maize and the maize mutant orange pericarp were shown to contain the necessary enzymes to convert [14C]indole to IAA. The reaction was not inhibited by unlabeled Trp and neither [14C]Trp nor [14C]serine substituted for [14C]indole in this in vitro system. The reaction had a pH optimum greater than 8.0, required a reducing environment, and had an oxidation potential near that of ascorbate. The results obtained with this in vitro enzyme preparation provide strong, additional evidence for the presence of a Trp-independent IAA biosynthesis pathway in plants.

Metabolism of Indole-3-Acetic Acid in Arabidopsis1

The metabolism of indole-3-acetic acid (IAA) was investigated in 14-d-old Arabidopsis plants grown in liquid culture. After ruling out metabolites formed as an effect of nonsterile conditions, high-level feeding, and spontaneous interconversions, a simple metabolic pattern emerged. Oxindole-3-acetic acid (OxIAA), OxIAA conjugated to a hexose moiety via the carboxyl group, and the conjugates indole-3-acetyl aspartic acid (IAAsp) and indole-3-acetyl glutamate (IAGlu) were identified by mass spectrometry as primary products of IAA fed to the plants. Refeeding experiments demonstrated that none of these conjugates could be hydrolyzed back to IAA to any measurable extent at this developmental stage. IAAsp was further oxidized, especially when high levels of IAA were fed into the system, yielding OxIAAsp and OH-IAAsp. This contrasted with the metabolic fate of IAGlu, since that conjugate was not further metabolized. At IAA concentrations below 0.5 μm, most of the supplied IAA was metabolized via the OxIAA pathway, whereas only a minor portion was conjugated. However, increasing the IAA concentrations to 5 μm drastically altered the metabolic pattern, with marked induction of conjugation to IAAsp and IAGlu. This investigation used concentrations for feeding experiments that were near endogenous levels, showing that the metabolic pathways controlling the IAA pool size in Arabidopsis are limited and, therefore, make good targets for mutant screens provided that precautions are taken to avoid inducing artificial metabolism.

Indole-3-Acetic Acid Controls Cambial Growth in Scots Pine by Positional Signaling1

The vascular cambium produces secondary xylem and phloem in plants and is responsible for wood formation in forest trees. In this study we used a microscale mass-spectrometry technique coupled with cryosectioning to visualize the radial concentration gradient of endogenous indole-3-acetic acid (IAA) across the cambial meristem and the differentiating derivatives in Scots pine (Pinus sylvestris L.) trees that had different rates of cambial growth. This approach allowed us to investigate the relationship between growth rate and the concentration of endogenous IAA in the dividing cells. We also tested the hypothesis that IAA is a positional signal in xylem development (C. Uggla, T. Moritz, G. Sandberg, B. Sundberg [1996] Proc Natl Acad Sci USA 93: 9282–9286). This idea postulates that the width of the radial concentration gradient of IAA regulates the radial number of dividing cells in the cambial meristem, which is an important component for determining cambial growth rate. The relationship between IAA concentration in the dividing cells and growth rate was poor, although the highest IAA concentration was observed in the fastest-growing cambia. The radial width of the IAA concentration gradient showed a strong correlation with cambial growth rate. The results indicate that IAA gives positional information in plants.

Regulation of Oleoresinosis in Grand Fir (Abies grandis)1 : Differential Transcriptional Control of Monoterpene, Sesquiterpene, and Diterpene Synthase Genes in Response to Wounding

Grand fir (Abies grandis Lindl.) has been developed as a model system for the study of wound-induced oleoresinosis in conifers as a response to insect attack. Oleoresin is a roughly equal mixture of turpentine (85% monoterpenes [C10] and 15% sesquiterpenes [C15]) and rosin (diterpene [C20] resin acids) that acts to seal wounds and is toxic to both invading insects and their pathogenic fungal symbionts. The dynamic regulation of wound-induced oleoresin formation was studied over 29 d at the enzyme level by in vitro assay of the three classes of synthases directly responsible for the formation of monoterpenes, sesquiterpenes, and diterpenes from the corresponding C10, C15, and C20 prenyl diphosphate precursors, and at the gene level by RNA-blot hybridization using terpene synthase class-directed DNA probes. In overall appearance, the shapes of the time-course curves for all classes of synthase activities are similar, suggesting coordinate formation of all of the terpenoid types. However, closer inspection indicates that the monoterpene synthases arise earlier, as shown by an abbreviated time course over 6 to 48 h. RNA-blot analyses indicated that the genes for all three classes of enzymes are transcriptionally activated in response to wounding, with the monoterpene synthases up-regulated first (transcripts detectable 2 h after wounding), in agreement with the results of cell-free assays of monoterpene synthase activity, followed by the coordinately regulated sesquiterpene synthases and diterpene synthases (transcription beginning on d 3–4). The differential timing in the production of oleoresin components of this defense response is consistent with the immediate formation of monoterpenes to act as insect toxins and their later generation at solvent levels for the mobilization of resin acids responsible for wound sealing.

Tobacco alkaloids.

A reprint from Vegetable alkaloids ... by Amé Pictet, rendered into English, by H.C. Biddle.

De origine et indole arabicae librorum V.T. historicorum interpretationis libri duo.

Mode of access: Internet.

D. Lud. Gottfred. Kleinii ... Interpres clinicus, sive De morborum indole, exitu in sanitatem, metaschematismo, successionibus, evento funesto, dijudicationes, praesagitiones medicae, pagellae in memoriae subsidium medicis junioribus, ad infirmos ingressuris, fideliter communicatae /

Mode of access: Internet.

Observationum Felicis Plateri ... libri tres totidem praxeos eius tractatibus, indole & methodo respondentes, atque affectuum corporis & animi plurimorum tum historias fide ac sedulo observatas, tum curationes feliciter praestitas, graphice enarrantes ; Tertia nunc vice typis mandati, ac praeter medicamentorum anakephalaiosin, & indicem rerum fructuosissimum, secunda editione, adjecta; ab innumeris mendis, in prioribus duabus, praetermissis, repurgati. Nova insuper, Fel. Plateri, Fel. ex Fr. nep. selectiorum observationum Mantissa, locupletati /

Contiene con port. y paginación propias: Felicis Plateri ... Observationum selectiorum ... Mantissa ...

D. Lud. Gottfr. Kleinii ... Interpres clinicus sive De morborum indole, exitu in sanitatem, Metaschematismo, successionibus, eventu funesto dijudicationes, praesagitiones medicae : pagellae in memoriae subsidium medicis junioribus ad infirmos ingressuris, fideliter communicatae comitatur opusculum /

Mode of access: Internet.

D. Lud. Gotfr. Kleinii ... Interpres clinicus sive De morborum indole, exitu in sanitatem, Metaschematismo, successionibus, eventu funesto diiudicationes, praesagitiones medicae, pagellae in memoriae subsidium medicis iunioribus ad infirmos ingressuris, fideliter communicatae comitatur opusculum /

Mode of access: Internet.

Interpres clinicus D. Lud. Gotfr. Kleinii ... sive dijudicationes, et praesagitiones medicae de morborum indole ... /

Mode of access: Internet.

Iohannis Linder ... De venenis in genere & in specie exercitatio : videlicet, eorum natura & in corpus agendi modo atque eadem, pro morbi acuti vel chronici ex iisdem oborientis indole , curandi : & in esculentis, potulentisque indagandi ratione juxta veterum quorundam & recentiorum dogmata ad solidorum & fluidorum corporis organici leges mechanicas deducta & explicata.

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Compendio de la vida y hechos de Joseph Balsamo llamado el conde calliostro : que se ha sacado del proceso formado contra él en Roma el año de 1790, y que puede servir de regla para conocer la indole de la secta de los francsmasones /

Mode of access: Internet.

Petri Tamburini Brixiani ... De fontibus sacrae theologiae deq. constitutione et indole ecclesiae christianae, eiusque regimine : volumen II, De Verbo Dei ...

Mode of access: Internet.

Haereticus Araneus, ex cuius natura et indole vniuersa haereseos oeconomia et technae liquidò lepidéque demonstrantur /

ICCU,