Particulate and soluble forms of o-diphenol oxidase from potato tubers

A soluble and two different particulate forms of o-diphenol oxidase have been obtained from aged or fresh potato slices by differential and density gradient centrifugation. The particulate enzymes were shown to sediment with microsomes and peroxisomes, respectively. Over half the enzyme activity of aged slices was found to be particle bound, with approximately twice as much enzyme in the microsomes as in the peroxisomal fraction. Very similar distribution patterns have been obtained with fresh potatoes, which have an o-diphenol oxidase activity approximately one-third that of aged slices.     

Ribonucleic acid metabolism during the development and ripening of tomato fruits

The accumulation of RNA in the outer locule tissue of tomato fruits was measured during development and ripening. Labelling studies suggest two peaks of synthesis, the first during early development and the second just before the onset of ripening (colour change). During the second period of increased RNA labelling the amount of total RNA per fruit either remains constant or starts to decline. Synthesis of rRNA and soluble RNA occurred at all stages. Polydisperse RNA containing polyadenylic acid was isolated and shown to direct the synthesis of protein in vitro. No significant changes in the amount of polyadenylic acid, relative to total RNA were detectable during the ripening period.     

An arabinoxyloglucan from extracellular polysaccharides of suspension-cultured tobacco cells

An arabinoxyloglucan (AXG) isolated from extracellular polysaccharide of suspension-cultured tobacco cells was investigated by methylation analysis, partial acid hydrolysis and ¹³C NMR spectroscopy. It was found that the AXG is structurally similar to that isolated from the midrib of tobacco leaves.     

Zunahme von cytokinin und auxin in verwundetem speichergewebe von Solanum tuberosum

“Butanol-soluble” cytokinins increase in grated and in lighted cut potato tissue. In slices, an increase of “water soluble” cytokinins (darkness and of tRNA-cytokinins can be found. Together with auxin, the cytokinin factor stimulates cell division in wound tissue.     

Zur biogenese des tigogenins in Digitalis lanata und des solasodins in Solanum laciniatum

7α-[³H]-20-hydroxycholesterol was converted by Digitalis lanata plants into tigogenin. 7α-[³H]-20-hydroxycholesterol and 7α-[³H]-26-aminodihydrodiosgenin were utilized for the biogenesis of solasodine by plants of Solanum laciniatum. These results are discussed in relation to spirostanol and spirosolan alkaloid biogenesis.     

Two labdane diterpenoids from Nicotiana raimondii

Two new labdanoids from Nicotiana raimondii have been identified as (12E) - 7β - hydroxylabda - 8(20),12,14 - triene and 7β - hydroxy - labda - 8(20),13(16),14 - triene.     

1β-Hydroxyneotigogenin,a sapogenin from Solanum polyadenium leaves

A new sapogenin has been isolated from leaves of Solanum polyadenium P.I. 161728, a clone that is highly resistant to Colorado potato beetle and potato leaf hopper. The structure of this compound has been established as 1β-hydroxyneotigogenin, 5α-spirostan-1β,3β-diol.     

Hyoscyamine N-oxide in Atropa belladonna

Separated organs of Atropa belladonna have been examined for their total alkaloid, hyoscyamine and hyoscyamine N-oxide contents during ontogenesis. Marked fluctuations in N-oxide content were observed, the highest being found in the ripe fruit. [G-³H]-atropine was fed to A. belladonna fruits and radioactively labelled hyoscyamine N-oxide isolated.