Within-plant distribution of 1,4-benzoxazin-3-ones contributes to herbivore niche differentiation in maize

Plant defences vary in space and time, which may translate into specific herbivore-foraging patterns and feeding niche differentiation. To date, little is known about the effect of secondary metabolite patterning on within-plant herbivore foraging. We investigated how variation in the major maize secondary metabolites, 1,4-benzoxazin-3-one derivatives (BXDs), affects the foraging behaviour of two leaf-chewing herbivores. BXD levels varied substantially within plants. Older leaves had higher levels of constitutive BXDs while younger leaves were consistently more inducible. These differences were observed independently of plant age, even though the concentrations of most BXDs declined markedly in older plants. Larvae of the well-adapted maize pest Spodoptera frugiperda preferred and grew better on young inducible leaves irrespective of plant age, while larvae of the generalist Spodoptera littoralis preferred and tended to grow better on old leaves. In BXD-free mutants, the differences in herbivore weight gain between old and young leaves were absent for both species, and leaf preferences of S. frugiperda were attenuated. In contrast, S. littoralis foraging patterns were not affected. In summary, our study shows that plant secondary metabolites differentially affect performance and foraging of adapted and non-adapted herbivores and thereby likely contribute to feeding niche differentiation

Natural Variation in Maize Aphid Resistance Is Associated with 2,4-Dihydroxy-7-Methoxy-1,4-Benzoxazin-3-One Glucoside Methyltransferase Activity

Plants differ greatly in their susceptibility to insect herbivory, suggesting both local adaptation and resistance tradeoffs. We used maize (Zea mays) recombinant inbred lines to map a quantitative trait locus (QTL) for the maize leaf aphid (Rhopalosiphum maidis) susceptibility to maize Chromosome 1. Phytochemical analysis revealed that the same locus was also associated with high levels of 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one glucoside (HDMBOA-Glc) and low levels of 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one glucoside (DIMBOA-Glc). In vitro enzyme assays with candidate genes from the region of the QTL identified three O-methyltransferases (Bx10a-c) that convert DIMBOA-Glc to HDMBOA-Glc. Variation in HDMBOA-Glc production was attributed to a natural CACTA family transposon insertion that inactivates Bx10c in maize lines with low HDMBOA-Glc accumulation. When tested with a population of 26 diverse maize inbred lines, R. maidis produced more progeny on those with high HDMBOA-Glc and low DIMBOA-Glc. Although HDMBOA-Glc was more toxic to R. maidis than DIMBOA-Glc in vitro, BX10c activity and the resulting decline of DIMBOA-Glc upon methylation to HDMBOA-Glc were associated with reduced callose deposition as an aphid defense response in vivo. Thus, a natural transposon insertion appears to mediate an ecologically relevant trade-off between the direct toxicity and defense-inducing properties of maize benzoxazinoids.

3-β-d-Glucopyranosyl-6-methoxy-2-benzoxazolinone (MBOA-N-Glc) is an insect detoxification product of maize 1,4-benzoxazin-3-ones

In order to defend themselves against arthropod herbivores, maize plants produce 1,4-benzoxazin-3-ones (BXs), which are stored as weakly active glucosides in the vacuole. Upon tissue disruption, BXs come into contact with β-glucosidases, resulting in the release of active aglycones and their breakdown products. While some aglycones can be reglucosylated by specialist herbivores, little is known about how they detoxify BX breakdown products. Here we report on the structure of an N-glucoside, 3-β-d-glucopyranosyl-6-methoxy-2-benzoxazolinone (MBOA-N-Glc), purified from Spodoptera frugiperda faeces. In vitro assays showed that MBOA-N-Glc is formed enzymatically in the insect gut using the BX breakdown product 6-methoxy-2-benzoxazolinone (MBOA) as precursor. While Spodoptera littoralis and S. frugiperda caterpillars readily glucosylated MBOA, larvae of the European corn borer Ostrinia nubilalis were hardly able to process the molecule. Accordingly, Spodoptera caterpillar growth was unaffected by the presence of MBOA, while O. nubilalis growth was reduced. We conclude that glucosylation of MBOA is an important detoxification mechanism that helps insects tolerate maize BXs.

Induction and detoxification of maize 1,4-benzoxazin-3-ones by insect herbivores

In monocotyledonous plants, 1,4-benzoxazin-3-ones, also referred to as benzoxazinoids or hydroxamic acids, are one of the most important chemical barriers against herbivores. However, knowledge about their behavior after attack, mode of action and potential detoxification by specialized insects remains limited. We chose an innovative analytical approach to understand the role of maize 1,4-benzoxazin-3-ones in plant–insect interactions. By combining unbiased metabolomics screening and simultaneous measurements of living and digested plant tissue, we created a quantitative dynamic map of 1,4-benzoxazin-3-ones at the plant–insect interface. Hypotheses derived from this map were tested by specifically developed in vitro assays using purified 1,4-benzoxazin-3-ones and active extracts from mutant plants lacking 1,4-benzoxazin-3-ones. Our data show that maize plants possess a two-step defensive system that effectively fends off both the generalist Spodoptera littoralis and the specialist Spodoptera frugiperda. In the first step, upon insect attack, large quantities of 2-β-d-glucopyranosyloxy-4,7-dimethoxy-1,4-benzoxazin-3-one (HDMBOA-Glc) are formed. In the second step, after tissue disruption by the herbivores, highly unstable 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one (HDMBOA) is released by plant-derived β-glucosidases. HDMBOA acts as a strong deterrent to both S. littoralis and S. frugiperda. Although constitutively produced 1,4-benzoxazin-3-ones such as 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) are detoxified via glycosylation by the insects, no conjugation of HDMBOA in the insect gut was found, which may explain why even the specialist S. frugiperda has not evolved immunity against this plant defense. Taken together, our results show the benefit of using a plant–insect interface approach to elucidate plant defensive processes and unravel a potent resistance mechanism in maize.

Effects of pH, light and temperature on (1→3,1→4)-β-glucanase stability in wheat leaves

Changes in (1→3,1→4)-β-D-glucan endohydrolase (EC 3.2.1.73) protein levels were investigated in segments from second leaves of wheat (Triticum aestivum L.). The abundance of the enzyme protein markedly increased when leaf segments were incubated in the dark whereas the enzyme rapidly disappeared when dark-incubated segments were illuminated or fed with sucrose. Addition of cycloheximide (CHI) to the incubation medium led to the disappearance of previously synthesized (1→3,1→4)-β-glucanase and suppressed the dark-induced accumulation indicating that the enzyme was rather unstable. The degradation of (1→3,1→4)-β-glucanase was analyzed without the interference of de-novo synthesis in intercellular washing fluid (IWF). The loss of the enzyme protein during incubation of IWF (containing naturally present peptide hydrolases) indicated that the stability increased from pH 4 to pH 7 and that an increase in the temperature from 25 to 35 °C considerably decreased the stability. Chelating divalent cations in the IWF with o-phenanthroline also resulted in a lowered stability of the enzyme. A strong temperature effect in the range from 25 to 35 °C was also observed in wheat leaf segments. Diurnal changes in (1→3,1→4)-β-glucanase activity were followed in intact second leaves from young wheat plants. At the end of the dark period, the activity was high but constantly decreased during the light phase and remained low if the light period was extended. Activity returned to the initial level during a 10-h dark phase. During a diurnal cycle, changes in (1→3,1→4)-β-glucanase activity were associated with reciprocal changes in soluble carbohydrates. The results suggest that the synthesis and the proteolytic degradation of an apoplastic enzyme may rapidly respond to changing environmental conditions.

Extra-Blatt: Neueste Nachricht aus Dresden: Der gestern Abend um 10 1/4 Uhr angekommene Zug ...

Welsch (Projektbearbeiter): Reichsverfassungskampagne in Sachsen

Demokratische Thronrede: Am 22sten Mai 1848 nicht gehalten: Dem demokratischen Klubb gewidmet: Um 12 1/4 Uhr erscheint im Sitzungssaale der konstituirenden National-Versammlung nach Vortritt des gesammten Staatsministeriums ...

Welsch (Projektbearbeiter): Aufzählung enttäuschter Erwartungen in Form einer König Friedrich Wilhelm IV. in den Mund gelegten Rede, die dieser anläßlich der Eröffnung der Preußischen Nationalversammlung am 22. Mai 1848 nach Meinung des anonymen Verfassers hätte halten müssen, aber nicht gehalten hat: Neubestimmung der königlichen Machtbefugnisse durch die Preußische Nationalversammlung unter dem Aspekt der Volkssouveränität, Erklärung, sich den Beschlüssen der Frankfurter Nationalversammlung "gern" zu unterwerfen, Einräumung nicht näher definierter Sonderrechte an die unterprivilegierten Klassen, Bekenntnis zur Einheit Deutschlands, Verantwortlichmachung der "Reaktion" für die mangelnde "innere Ruhe" sowie die Erschöpfung der Staatskassen, lobende Hervorhebung der Bemühungen des Ministeriums Camphausen zur Mehrung der Geldmenge

Reversible accumulation of (1→3,1→4)‐β‐glucan endohydrolase in wheat leaves under sugar depletion

A (1→3,1→4)‐β‐D‐glucan endohydrolase [(1→3,1→4)‐β‐glucanase, EC 3.2.1.73] was detected in wheat (Triticum aestivum L.) leaves by Western analyses and activity measurements. This enzyme is able to degrade the (1→3,1→4)‐β‐glucans present in the cell walls of cereals and other grass species. In wheat, enzyme levels clearly increased during leaf development, reaching maximum values at full expansion and then decreasing upon leaf ageing. To test whether the abundance of (1→3,1→4)‐β‐glucanase might be controlled by the carbohydrate status, environmental and nutritional conditions capable of altering the leaf soluble sugar contents were used. Both the activity and enzyme protein levels rapidly and markedly increased when mature leaves were depleted of sugars (e.g. during extended dark periods), whereas elevated carbohydrate contents (e.g. following continuous illumination, glucose supply in the dark or nitrogen deficiency during a light/dark cycle) caused a rapid decrease in (1→3,1→4)‐β‐glucanase abundance or prevented its accumulation in the leaves. The physiological significance of (1→3,1→4)‐β‐glucanase accumulation under sugar depletion remains to be elucidated.

Fanny Lüneburger [Illustration] : geb. 1.4.1831, wohnhaft in Würzburg

Scan von Monochrom-Mikroform

INDUCTION OF DNA STRAND BREAKS AND CROSS-LINKS BY THE NEW ANTICANCER AGENT 3,6-DIAZIRIDINYL-2,5-BIS(CARBOETHOXYAMINO) -1,4-BENZOQUINONE

The DNA breakage effect of the anticancer agent 3,6-diaziridinyl-2,5-bis(carboethoxyamino)-1,4-benzoquinone (AZQ, NSC-182986) on bacteriophage PM2 DNA was investigated using agarose gel electrophoresis. AZQ caused both single-stranded and double-stranded breaks after reduction with NaBH(,4), but it was not active in the native state. At 120 (mu)M, it degraded 50% of the closed circular form I DNA into 40% form II DNA (single-stranded break) and 10% form III DNA (double-stranded break). It produced a dose-response breakage between 1 (mu)M and 320 (mu)M. The DNA breakage exhibited a marked pH dependency. At 320 (mu)M, AZQ degraded 80% and 60% of form I DNA at pH 4 and 10 respectively, but none between pH 6 to 8. The DNA breakage at physiologic pH was greatly enhanced when 10 (mu)M cupric sulfate was included in the incubation mixture. The DNA strand scission was inhibited by catalase, glutathione, KI, histidine, Tiron, and DABCO. These results suggest that the DNA breakage may be caused by active oxygen metabolites including hydroxyl free radical. The bifunctional cross-linking activity of reduced AZQ on isolated calf thymus DNA was investigated by ethidium fluorescence assay. The cross-linking activity exhibited a similar pH dependency; highest in acidic and alkaline pH, inactive under neutral conditions. Using the alkaline elution method, we found that AZQ induced DNA single-stranded breaks in Chinese hamster ovary cells treated with 50 (mu)M of AZQ for 2 hr. The single-stranded break frequencies in rad equivalents were 17 with 50 (mu)M and 140 with 100 (mu)M of AZQ. In comparison, DNA cross-links appeared in cells treated with only 1 to 25 (mu)M of AZQ for 2 hr. The cross-linking frequencies in rad equivalents were 39 and 90 for 1 and 5 (mu)M of AZQ, respectively. Both DNA-DNA and DNa-protein cross-links were induced by AZQ in CHO cells as revealed by the proteinas K digestion assay. DNA cross-links increased within the first 4 hr of incubation in drug-free medium and slightly decreased by 12 hr, and most of the cross-links disappeared after cells were allowed to recovered for 24 hr.^ By electrochemical analysis, we found that AZQ was more readily reduced at acidic pH. However, incubation of AZQ with NaBH(,4) at pH 7.8 or 10, but not at 4, produced superoxide anion. The opening of the aziridinyl rings of AZQ at pH 4 was faster in the presence of NaBH(,4) than in its absence; no ring-opening was detected at pH 7.8 regardless of the inclusion of NaBH(,4). . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI ^

Der Segen Jakobs : Midrasch Bereschith rabba ; Par. 98,1-20, 99,1-4

Bern, Univ., Diss., 1900

Fragm. lat. III 6 - Notula ad Compilationem III iuris canonici (Comp. III 1.3.7/1.4.1)

Trägerband: Ms. Barth. 28; Vorbesitzer: Bartholomaeusstift Frankfurt am Main

Na 1 Nachlass Max Horkheimer, 634 - Aufsätze für die "Zeitschrift für Sozialforschung" und "Studies in Philosophy and Social Science" (p. IX 9.1-4-IX 10.1-7)

"Montaigne oder die Funktion der Skepsis" (GS 4, S.236-194), veröffentlicht in: Zeitschrift für Sozialforschung VII, 1938, S.1-54, englische Fassung des Aufsatzes, Typoskript, 69 Blatt; Exzerpte: Montaigne im Urteil der Nachwelt, Typoskripte, 29 Blatt; handschriftliche Stichworte zu Montaigne, 10 Blatt; 2 Zeitungsausschnitte; Leihscheine der Columbia University Library für Bücher über Montaigne; "Die Juden und Europa" (GS 4, S.308-331), veröffentlicht in: Studies in Philosophy and Social Science VIII, 1939, S. 115-137, a) Typoskript mit eigenhändigen Korrekturen, 31 Blatt, b) Typoskript mit eigenhändigen und handschriftlichen Korrekturen, 32 Blatt, c) Typoskript mit handschriftlichen Korrekturen, 27 Blatt, d) Typoskript mit handschriftlichen Korrekturen, Teilstücke, 16 Blatt, e) Typoskript mit eigenhändigen und handschriftlichen Korrekturen, 20 Blatt, f) überholte Formulierungen, Typoskript mit handschriftlichen Korrekturen, 10 Blatt; Bemerkungen zum Verhältnis von Liberalismus und Antisemitismus, a) Typoskript, 4 Blatt, b) Typoskript mit eigenhändigen Korrekturen, 9 Blatt (als Nachbemerkung zu: Ernst Engelberg: Exzerpt zu W. Frank und W. Grau), Typoskript, 1 Blatt; Exzerpte zu: Alvin Johnson, Honoré de Balzac, Guy de Maupassant, Paul Mahn, Marcel Proust, Anatole France, Marcel le Goff, Emile Zola, Typoskripte, 58 Blatt; Otto Kirchheimer: "Produktionswandel und Konzentrationstendenzen im Bankgewerbe", Typoskript, 2 Blatt; eigenhändige Adressennotiz, 1 Blatt; Otto Kirchheimer: "Reprivatisierungstendenzen des Faschismus", Typoskript mit eigenhändiger Ergänzung, 12 Blatt; Zeitungsausschnitte zur wirtschaftlichen Entwicklung, 1938, 8 Blatt;

Na 1 Nachlass Max Horkheimer, 645 - "Geschichte und Psychologie", "Preface" und "Vorurteil und Charakter" (p. IX 25a-IX 27.1-4)

"Geschichte und Psychologie" (GS 3, S. 48-69); Photokopie des Drucks aus der Zeitschrift für Sozialforschung, Jahrgang I, 1932; mit handschriftlichen Korrekturen von Gretel Adorno für den Nachdruck (1968), 11 Blatt; "Preface" to Berkeley Adult Study (GS 5, S. 415-420); Veröffentlicht in: Adorno, Theodor W.; Frenkel-Brunswik, Else; Levinson, Daniel J.; Sanford, R. Nevitt: "The Authoritian Personality", New York, 1950, Seote IX- XII. Typoskript, datiert: April 1948, 8 Blatt (siehe auch IX 140, IX 153.3); "Vorurteil und Charakter" (GS 8, Seite 64-76); 1. Aufsatz von Max Horkheimer und Theodor W. Adorno, veröffentlicht in: Frankfurter Hefte; April 1952, Seite 284-291. a) Teilstück, Typsokript, 2 Blatt b) Typoskript mit eigenhändigen und handschriftlichen Korrekturen, 14 Blatt c) Typoskript mit dem Titel: "Vorurteil: Wissenschaftlich untersucht. Der freie und der totalitäre Mensch"; mit handschriftlichen Korrekturen, 5 Blatt d) Typsokript mit demselben Titel, mit eigenhändigen Korrekturen von Max Horkheimer und Theosodr W. Adorno, 6 Blatt; 2. Englische Fassung mit dem Titel: "Prejudice and Personality". a) Typoskript, 14 Blatt b) Typoskript, 14 Blatt; 3. Horkheimer, Max: "Prejudice and Personality. A Paper prepared for the XII th Congress of the International Association of Allied Psychology as a Contribution to the Symposion on: 'The Psychologist ams Scienty'". London, July 19, 1955; 2. überarbeitete Fassung, Typoskript, 7 Blatt; 4. "Vorurteil"; größtenteils identisch mit 1. Typsokript, 10 Blatt (siehe auch IX 28.8);