Biotransformation of reticuline into coreximine,scoulerine, pallidine,and isoboldine with rat liver enzyme

(±)-Reticuline (1) was biotransformed into the protoberberine alkaloids, coreximine (12) and scoulerine (10), the morphinandienone alkaloid, pallidine (14), and the aporphine alkaloid, isoboldine (16). The transformation was stimulated by O₂ and the cofactor NAD, NADP, or NADPH, NADPH being more effective than the other cofactors. The N-methyl group of (±)-reticuline was not incorporated intact into protoberberines.     

Regulation of Polyphosphoinositide Metabolism in Pea Plasma Membranes by Elicitor and Suppressor from a Pea Pathogen, Mycosphaerella pinodes

Effects of the elicitor and the suppressor from a pea pathogen,Mycosphaerella pinodes, on polyphosphoinositide metabolism inpea plasma membranes were examined in vitro. Lipid phosphorylationin the isolated pea plasma membrane was drastically stimulatedby the elicitor, but markedly inhibited by the suppressor. Asimilar inhibitory effect was observed by the treatment withorthovanadate or K-252a that blocked pisatin production inducedby the elicitor. Neomycin, an aminoglycoside antibiotic thatinteracts with the polyphosphoinositide metabolism, also affectedthe lipid phosphorylation in vitro and blocked the elicitor-inducedaccumulation of pisatin in vivo. These results suggest thatrapid changes of polyphosphoinositide metabolism in pea plasmamembranes is one of indispensable processes during the elicitationof defense responses. (Received January 22, 1992; Accepted March 23, 1992)     

Expression of neuron-specific enolase in the pineal organ of the domestic fowl during post-hatching development

Immunohistochemistry for neuron-specific enolase (NSE) revealed that NSE is localized in both a limited number of pinealocytes and intrinsic afferent neurons in the pineal organ of the domestic fowl. Furthermore, a computer-assisted three-dimensional imaging technique allowed to clarify the reverse distributional pattern of both elements: NSE-positive pinealocytes displayed a dense distribution especially in the vesicular portion of the gland, whereas NSE-immunoreactive nerve cells were mainly found in the pineal stalk. The number of NSE-positive intrinsic neurons in the pineal organ of chickens decreased rapidly after hatching, with a concentration of these elements in the basal portion (stalk) of the pineal organ. On the other hand, immunoreactive pinealocytes increased remarkably in the end-vesicle of the organ with age, followed by a gradual expansion toward the proximal portion. Thus, the spectacular increase in NSE-positive pinealocytes and the progressive reduction of reactive neurons occurred in parallel during the course of post-hatching development. NSE-immunoreactive pinealocytes displayed morphological characteristics of bipolar elements, endowed with an apical protrusion into the pineal lumen and a short basal process at younger stages, whereas multipolar types of NSE-positive pinealocytes were predominantly found in the adult domestic fowl. These results indicate that in the pineal organ of the domestic fowl (1) the ontogenetic expansion of NSE-immunoreactive pinealocytes is paralleled by a regressive afferent innervation, (2) the NSE-positive pinealocytes transform from a bipolar (columnar) type to a multipolar type during post-hatching development, and (3) these ontogenetic changes in the NSE-immunoreactivity and morphology of pinealocytes may reflect the development of a neurosecretory-like capacity of the organ.     

Genetic characterization of late-flowering traits induced by DNA hypomethylation mutation in Arabidopsis thaliana

Arabidopsis DNA hypomethylation mutation, ddm1 , results in a variety of developmental abnormalities by slowly inducing heritable lesions at unlinked loci. Here, late-flowering traits observed at high frequencies in independently-established ddm1 lines were genetically characterized. In all of the four late-flowering lines examined the traits were dominant and mapped to the same chromosomal region, which is close or possibly identical to the FWA locus. The ddm1 -induced phenotypic onsets are apparently not random mutation events, but specific to a group of genes, suggesting the underlying epigenetic mechanism. The DNA methylation mutant provide useful system for identifying epigenetically-regulated genes important for plant development.