Bendigoles A approximately C, new steroids from Gordonia australis Acta 2299.
ABSTRACT Bendigoles A approximately C are the first secondary metabolites to be isolated from a member of the actinomycete genus Gordonia. They were detected in a culture filtrate extract of Gordonia australis Acta 2299 by HPLC-diode array analysis and characterized as new steroids by mass spectrometry and NMR experiments. Bendigole C show binding affinity to the human progesterone and A approximately C to androgen receptor but are inactive at mineralocorticoid and estrogen receptors. In in vitro transactivation studies bendigoles A and C showed moderate and weak androgenic activities.
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ABSTRACT: Sterol biosynthesis is viewed primarily as a eukaryotic process, and the frequency of its occurrence in bacteria has long been a subject of controversy. Two enzymes, squalene monooxygenase and oxidosqualene cyclase, are the minimum necessary for initial biosynthesis of sterols from squalene. In this work, 19 protein gene sequences for eukaryotic squalene monooxygenase and 12 protein gene sequences for eukaryotic oxidosqualene cyclase were compared with all available complete and partial prokaryotic genomes. The only unequivocal matches for a sterol biosynthetic pathway were in the proteobacterium, Methylococcus capsulatus, in which sterol biosynthesis is known, and in the planctomycete, Gemmata obscuriglobus. The latter species contains the most abbreviated sterol pathway yet identified in any organism. Analysis shows that the major sterols in Gemmata are lanosterol and its uncommon isomer, parkeol. There are no subsequent modifications of these products. In bacteria, the sterol biosynthesis genes occupy a contiguous coding region and possibly comprise a single operon. Phylogenetic trees constructed for both enzymes show that the sterol pathway in bacteria and eukaryotes has a common ancestry. It is likely that this contiguous reading frame was exchanged between bacteria and early eukaryotes via lateral gene transfer or endosymbiotic events. The primitive sterols produced by Gemmata suggest that this genus could retain the most ancient remnants of the sterol biosynthetic pathway.Proceedings of the National Academy of Sciences 01/2004; 100(26):15352-7. · 9.74 Impact Factor
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ABSTRACT: Three strains of non-motile, Gram-positive, filamentous actinomycetes, isolates J4(T), J5 and J59, initially recognized microscopically in activated sludge foam by their distinctive branching patterns, were isolated by micromanipulation. The taxonomic positions of the isolates were determined using a polyphasic approach. Almost-complete 16S rRNA gene sequences of the isolates were aligned with corresponding sequences of representatives of the suborder Corynebacterineae and phylogenetic trees were inferred using three tree-making algorithms. The organisms formed a distinct phyletic line in the Gordonia 16S rRNA gene tree. The three isolates showed 16S rRNA gene sequence similarities within the range 96.9-97.2 % with their nearest phylogenetic neighbours, namely Gordonia bronchialis DSM 43247(T) and Gordonia terrae DSM 43249(T). Strain J4(T) was shown to have a chemotaxonomic profile typical of the genus Gordonia and was readily distinguished from representatives of the genus on the basis of Curie-point pyrolysis mass spectrometric data. The isolates shared nearly identical phenotypic profiles that distinguished them from representatives of the most closely related Gordonia species. It is evident from the genotypic and phenotypic data that the three isolates belong to a novel Gordonia species. The name proposed for this taxon is Gordonia defluvii sp. nov.; the type strain is J4(T) (=DSM 44981(T)=NCIMB 14149(T)).International journal of systematic and evolutionary microbiology 11/2006; 56(Pt 10):2265-9. · 2.11 Impact Factor
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ABSTRACT: Right-angle branched filaments and rods micromanipulated from activated sludge foam and mixed liquor were identified as putatively novel members of the genera Gordonia, Mycobacterium and Rhodococcus using a combination of chemical, molecular and morphological data. Pyrolysis mass spectrometric analyses of gordoniae isolated in both the present and a previous study revealed pyro-groups, distinct from validly described Gordonia species, which could be equated with those based on morphological properties and 16S rDNA data. Putative gordoniae assigned to one of these groups were found to be closely related to strains currently identified as "Rhodococcus australis". These strains were also found to have properties consistent with their classification in the genus Gordonia. The results of this study highlight the limitations of the microscopic approach to filament identification and cast further doubt on the view that foaming can be attributed to members of one or a few Nocardia species.Water Science & Technology 02/2002; 46(1-2):81-90. · 1.10 Impact Factor