Polyphasic taxonomy of Aspergillus section Candidi based on molecular, morphological and physiological data

Aspergillus section Candidi historically included a single white-spored species, A. candidus. Later studies clarified that other species may also belong to this section. In this study, we examined isolates of species tentatively assigned to section Candidi using a polyphasic approach. The characters examined include sequence analysis of partial β-tubulin, calmodulin and ITS sequences of the isolates, morphological and physiological tests, and examination of the extrolite profiles. Our data indicate that the revised section Candidi includes 4 species: A. candidus, A. campestris, A. taichungensis and A. tritici. This is strongly supported by all the morphological characteristics that are characteristic of section Candidi: slow growing colonies with globose conidial heads having white to yellowish conidia, conidiophores smooth, small conidiophores common, metulae present and covering the entire vesicle, some large Aspergillus heads with large metulae, presence of diminutive heads in all species, conidia smooth or nearly so with a subglobose to ovoid shape, and the presence of sclerotia in three species (A. candidus, A. taichungensis and A. tritici). Aspergillus tritici has been suggested to be the synonym of A. candidus previously, however, sequence data indicate that this is a valid species and includes isolates came from soil, wheat grain, flour and drums from India, Ghana, Sweden, The Netherlands and Hungary, making it a relatively widespread species. All species produce terphenyllins and candidusins and three species (A. candidus, A. campestris and A. tritici) produce chlorflavonins. Xanthoascins have only been found in A. candidus. Each of the species in section Candidi produce several other species specific extrolites, and none of these have been found in any other Aspergillus species. A. candidus has often been listed as a human pathogenic species, but this is unlikely as this species cannot grow at 37 °C. The pathogenic species may be A. tritici or white mutants of Aspergillus flavus

Crystal Structure of (-)-Corycavinium(+)-10-Camphorsulfonate, a Biosynthetic Intermediate to Hexahydrobenzo[c]phenanthridine Alkaloids

The crystal structure of (—)-corycavinium (+)-10-camphorsulfonate has been investigated by X-ray analysis. The structure of (-)-corycavinium ion ( = (-)-(7S,13S,14R)-5,6,13,13a-tetrahydro-l3a-hydroxy-7-methyl- 2,3;9,10-bis(methylenedioxy)-8H-dibenzo[a,g]quinolizinium), has been determined. The conformation with B/Ccis -conjunction, a twisted half-chair of ring B, and a half-chair of ring C, as well as a -oriented substituted groups N - M e , C - Me, and C - O H is revealed. Feeding experiments with cell suspension cultures of Corydalis incisa (Papaveraceae) defined the intermediacy of (—)-corycavinium in the route from protoberberine-type to hexahydrobenzo[ c]phenanthridine-type of alkaloids. On the basis of the present crystal conformation, the stereospecificity of the relating enzyme is biogenetically considered

O-Methylating Enzymes of Dopamine and Dopamine Derived Tetrahydroisoquinoline, Salsolinol

By using an LC/API-MS system, it was demonstrated that dopamine condenses with acetaldehyde to give salsolinol which is further metabolized to produce 6-O-methylsalsolinol (isosalsoline) which is O- and N-methylated to provide salsolidine and N-methylisosalsoline, respectively, in several plant tissue cultures of Papaveraceae. Almost none of the 3-O-methoxytyramine formed from dopamine was metabolized into simple isoquinoline derivatives. Although salsolinol and 3-O-methoxytyramine were formed from dopamine, no O-methylatedsalsolinol was formed in tissue cultures of Cynanchum vincetoxicum (Asclepiadaceae). The results suggest that the O-methylating enzymes of salsolinol may be different to those of dopamine

Degradation of some Phthalideisoquinolines with Ethyl Chloroformate-Stereochemical Aspects

Treatment of phthalideisoquinolines such as α- (1) and β-narcotine (2) as well as ß-(3) and α-hydrastine (4) with ethyl chloroformate (ECF) at room temperature afforded, via the chloro-carbamates, the corresponding diastereomeric carbinols with high stereoselectivity. Instrumental analyses of each diastereomeric pair indicate that the major isomers derived from α- and β-narcotine as well as from α - and β -hydrastine are enantiomers of each other. The absolute configuration of the major carbinol 6a from α -narcotine (1) was determined by X-ray analysis. The probable difference between the reaction course of α - and β-narcotine is discussed. On the other hand, treatment of α-narcotine with ECF under reflux furnished Z-(8) and E-(9) enol lactones, while only the Z-isomer 12 could be isolated from the degradation of β-hydrastine (3) even at room temperature