C andH NMR spectroscopy as a tool in the configurational analysis of iridoid glucosides

The ¹³C NMR data of 51 iridoid glucosides or glucoside acetates are tabulated. The collection includes 20 pairs of C-6, C-7 or C-8 epimers. Three parameters in using the data for the configurational assignment of 6-O-substituents are given. The chemical shift for C-9 in a range of substituted compounds is shown to be numerically related to the stereochemistry at C-8. This allows the determination of the configuration at this centre for most types of substitution patterns by calculation of the C-9 shift using increments for each substituent. Such increments are given for 25 substituents in three different solvents. A method for simulation of spectra of unknown iridoid glucosides is presented. By this method, the structures of five novel iridoid glucosides have been elucidated, and that of tecomoside has been revised. The methods used to assign the configurations to C-6 and C-8 epimeric iridoid glucosides by ¹H NMR spectroscopy are discussed and a table with selected data is presented. It is suggested that the structures in the literature for ajugol and myoporoside should be interchanged. Consequently, Horeau's method has failed in these instances. Finally, the differences in the ¹³C NMR spectra of pairs of C-6 and C-8 epimeric iridoid glucosides have been interpreted as originating from cis/trans-interactions.     

Fragile site long arm chromosome 16

Summary A fragile site at the long arms (q21) of chromosome 16 was found in two persons, each of whom became the parent of a child with a de novo structural chromosome abnormality—a balanced autosomal translocation and an autosomal deletion. The question of an increased risk of structural chromosome abnormalities in the offspring of persons with fragile site long arm 16 is discussed.     

Host plant discrimination within Cruciferae: Feeding responses of four leaf beetles (Coleoptera: Chrysomelidae) to glucosinolates, cucurbitacins and cardenolides

Feeding responses of four Chrysomelidae to six less acceptable plants and to compounds from them were investigated by means of leaf disc tests. Significant differences were found between responses of different species, and plants containing potent feeding inhibitors were always rejected. Cucurbitacins are potent feeding inhibitors to Phyllotreta nemorum, and this species does not eat Iberis species containing these compounds. Cardenolides are potent feeding inhibitors to P. undulata, P. tetrastigma and Phaedon cochleariae, and these three species do not eat the cardenolide containing Cheiranthus and Erysimum.Six different glucosinolates all proved to be stimulatory when applied to pea leaf discs. Although the glucosinolates differed somewhat in their ability to stimulate feeding, no correlation is found between content of glucosinolates and acceptability of the investigated plants. Application of sinigrin to Iberis and Cheiranthus did not improve their acceptability. The presence of glucosinolates is necessary for feeding to occur, but it is less important which glucosinolates are present.Cardenolides and cucurbitacins are suggested to be a second generation of protective compounds in Cruciferae, glucosinolates being the first.

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Zusammenfassung Der Einfluss einiger sekundärer Pflanzenstoffe aus Cruciferen auf die Futteraufnahme von vier Chrysomeliden, die auf dieser Pflanzenfamilie vorkommen, wurde mittels Blattscheiben-Tests untersucht. Cucurbitacine sind starke Frasshemmstoffe für Phyllotreta nemorum, weniger starke Hemmstoffe für P. undulata und schwache Hemmstoffe für P. tetrastigma und Phaedon cochleariae. Iberis-Arten, die Cucurbitacine enthalten, werden von P. nemorum und P. undulata abgelehnt, von den beiden anderen Arten aber akzeptiert. Cardenolid-Glykoside vom Strophanthidin-Typ sind starke Frasshemmstoffe für P. undulata, P. tetrastigma und Phaedon cochleariae. Diese Arten lehnen Cheiranthus-und Erysimum-Arten, die solche Stoffe enthalten, ab. Die Futteraufnahme von P. nemorum wird von diesen Stoffen nicht beeinflusst; P. nemorum akzeptiert Cheiranthus- und Erysimum-Arten.Futteraufnahme fand bei Abwesenheit von Senfölglukosiden nicht statt. Sechs verschiedene Senfölglukoside waren alle imstande, das Aufnehmen von Erbsen-Blattscheiben zu stimulieren. Gewisse Unterschiede in der stimulierenden Wirkung der einzelnen Glukoside wurden gefunden. Das Vorkommen bestimmter Glukoside und die Akzeptabilität der Pflanzen zeigten aber keine Korrelation. Anwesenheit oder Abwesenheit von Frasshemmstoffen beeinflusst die Akzeptabilität der Pflanzenarten mehr als die Anwesenheit bestimmter Senfölglukoside.Wenn Senfölglukoside als eine erste Generation von Abwehrstoffen in Cruciferen aufgefasst werden, können Cucurbitacine in Iberis und Cardenolid-Glykoside in Cheiranthus und Erysimum als eine zweite betrachtet werden.

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The Danish Natural Science Research Council supported the research.     

Deletion - translocation del (12) (p11) leads to (t10;12) (p13;pII).

Renewed examinatinon with improved banding techniques of a boy previously reported to have the karyotype 46, XY,del(12)(p11) revealed a translocation 46, XY,t(10;12)(p13;p11), and reexamination of a boy previously reported to have the karyotype 46,XY/46,XY,del(5)(p13) showed the same mosaicism, but with a significantly lower frequency of cells with del(5)(p13), 8% compared with 23% at the time of birth. The decrease of the frequency of cells with chromosome abnormality in mixoploids during the first years of life as found in the present case as well as in prevously reported cases is discussed.     

ESTIMATION OF NORADRENALINE AND ITS MAJOR METABOLITES SYNTHESIZED FROM [3H]TYROSINE IN THE RAT BRAIN

Abstract— A new procedure is described for the estimation of [³H]noradrenaline (NA) and its major metabolites free and conjugated 3-methoxy-4-hydroxyphenylglycol (MOPEG) and free and conjugated 3,4-dihydroxyphenylglycol (DOPEGI in the rat brain. The procedure involves adsorption on to alumina, cation exchange chromatography. enzymatic hydrolysis of conjugates and thin-layer-chromatography after intraventricular (IVT) or intravenous injection of [³H]tyrosine. In a time-course study the formation and accumulation of the metabolites have been measured from 15min to 23h after IVT injection of [³H]tyrosine. [³H]MOPEG and [³H]DOPEG were found in almost equal amounts during the synthesis phase of [³H]NA as well as during the storage and disappearance phase of [³H]NA. The maximum levels of conjugated [³H]MOPEG and conjugated [³H]DOPEG were found 2 h after IVT [³H]tyrosine. At this time interval the levels of free [³H]MOPEG and free [³H]DOPEG amounted to 25% and 11%, respectively of the corresponding conjugates. Increasing doses of IVT injected [³H]tyrosine (10-90 °Ci) revealed that the accumulation of [³H]NA and metabolites was linear up to about 50 °Ci. Following intravenous instead of IVT injection of [³H]tyrosine. much higher doses (325 °Ci) were needed to obtain measurable amounts of total [³H]MOPEG and [³H]DOPEG-SO₄ in the rat brain. The formation of labelled NA metabolites from [³H]NA in the rat brain in vim measured as total [³H]MOPEG and [³H]DOPEG-SO₄ was influenced by drugs affecting [³H]NA synthesis, release and metabolism. Synthesis inhibition with a-methyltyrosine (250mg-kg^?1) or FLA-63 (30mg-kg^?1) and inhibition of monoamine oxidase with pargyline (75mg-kg^?1) or clorgyline (2mg-kg^?1) strongly decreased the accumulation of total [³H]MOPEG and [³H]DOPEG-SO₄. Noradrenaline receptor blockade with phenoxybenzamine (20mg-kg^?1) increased both total [³H]MOPEG and [³H]DOPEG-SO₄ to about 160% of the control values. NA release and uptake inhibition induced by d-amphetamine (10mg-k^?1) or phenylethylamine (two doses of 80mg-kg^?1) decrease strongly the levels of [³H]NA and [³H]DOPEG-SO₄. whereas total [³H]MOPEG was only very slightly decreased or even increased as compared to controls.