Evidence for a cycloartenol-based sterol synthetic pathway inLagenidium spp.

Warner, Steven A.; Domnas, A.

doi:10.1016/0147-5975(81)90021-9

Cited by 20 publications

(12 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Clear evidence was obtained for the conversion of cycloartenol to lanosterol; however, the conversion efficiencydefined as the percent of sterol taken up that was converted-varied from organism to organism and ranged from 2% to 40%. Total neutral sterols were typically [5][6][7][8][9][10] …”

Section: Resultsmentioning

confidence: 99%

“…Sterols were identified by gas/liquid chromatography on 3% SE-30 and 1% QF-1 with a Packard 417 FID chromatograph as described (10). Confirmation ofidentification was obtained with gas chromatography/electron impact mass spectroscopy (70 eV) with a Finnegan 4023 instrument.…”

Section: Microorganismsmentioning

confidence: 99%

“…Inoculation and growth were as described (10) 7 days' growth were treated as described (10) and the unsaponifiable lipid fraction was obtained. The sterols were separated on HPLC with a Waters instrument by using a 10-,um C18 column (4.6 x 250 mm).…”

Section: Microorganismsmentioning

confidence: 99%

“…(3,14,15), whereas algae and land plants (16,17), Lagenidium species (10), and Saprolegnia species (18) of the Oomycetes cyclize this compound to cycloartenol. The metabolism of cycloartenol to lanosterol and other sterols by selected species of the Peronosporales indicates that the sterol synthetic pathway past the 2,3-oxidosqualene cyclase (10) showed that cycloartenol, but not lanosterol, produced fucosterol and cholesterol. Conversely, Z. insidians produces ergosterol along with trace amounts oflanosterol and 24-methyl sterols (20).…”

mentioning

confidence: 99%

See 3 more Smart Citations

Cycloartenol-derived sterol biosynthesis in the Peronosporales

Warner¹,

Eierman²,

Sovocool³

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Selected species of the order Peronosporales, which are unable to epoxidize squalene and thus synthesize sterols, are able to metabolize exogenous cycloartenol to lanosterol and in some organisms to fucosterol, ergosterol, and cholesterol. Lanosterol was less effectively utilized but some ergosterol and cholesterol were yielded. Fucosterol was very efficiently metabolized by most species to ergosterol, A7-ergostenol, A5-ergostenol, cholestanol, and cholesterol. Several unknown sterols were observed in most trials. These data suggest a vestigial sterol synthetic pathway derived from cycloartenol, followed by possible isomerization to lanosterol and then to other sterols.It has been established that species of Pythium and Phytophthora require exogenous sterols for sexual reproduction (1, 2). These organisms are unable to synthesize sterols because of a missing squalene epoxidase (3). Metabolism of exogenous sterols has been observed in Phytophthora cactorum by Langeake (4), who reported possible conversion of lanosterol to cholesterol. Nes and Patterson (5) reported that Phyt. cactorum was unable to transform cycloartenol or lanosterol to other sterols. Conversion ofA7 and A5'7 sterols to A5 sterols has been reported by Elliott and Knights (6) in Phyt. cactorum, which additionally synthesizes cholesteryl esters, cholesteryl glucosides, and acyl sterol glycosides (7,8). Other than the above, sterol conversions in Phytophthora or Pythium have, in general, not been demonstrated in detail.Lagenidium giganteum is another Oomycete, but of the Lagenidiales, that requires exogenous sterols to produce zoospores (9). Warner and Domnas (10) have shown that this organism converts cycloartenol, but not lanosterol, to cholesterol. Because Lagenidium species are able to metabolize cycloartenol, it was ofconsiderable interest to observe ifthis compound could be metabolized by selected species ofthe Peronosporales. This article reports our observations. Inoculation and growth were as described (10) (10) and the unsaponifiable lipid fraction was obtained. The sterols were separated on HPLC with a Waters instrument by using a 10-,um C18 column (4.6 x 250 mm). Fractions were eluted with methanol/H20 (96:4) at 2 ml/min flow with UV detection at 210 nm. MATERIALS AND METHODS MicroorganismsSterols were identified by gas/liquid chromatography on 3% SE-30 and 1% QF-1 with a Packard 417 FID chromatograph as described (10). Confirmation ofidentification was obtained with gas chromatography/electron impact mass spectroscopy (70 eV) with a Finnegan 4023 instrument. A 15-m flexible fused silica capillary coated with OV-101 was programmed from 160 to 2600C at 10°C/min with an initial hold of 3 min. RESULTSNo sterols were found in control organisms to the limit of detection (0.0001%). Uninoculated control cultures yielded a stoichiometric recovery of the administered sterols.Sterols Isolated After Administration ofCycloartenol. Table 1 illustrates the substances identified in the organisms examined. Clear evidence was obtained for the ...

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Microorganismsmentioning

confidence: 99%

Section: Microorganismsmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Cycloartenol-derived sterol biosynthesis in the Peronosporales

Warner¹,

Eierman²,

Sovocool³

et al. 1982

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Requirements for sterols have also been documented for asexual (11) and sexual (30) reproduction by the facultative mosquito parasite Lagenidiim ,ngiganteuim (Oomycetes:Lagenidiales), which cannot synthesize these compounds (60).…”

mentioning

confidence: 99%

Reassessment of the role of phospholipids in sexual reproduction by sterol-auxotrophic fungi

Kerwin

Duddles

1989

J Bacteriol

View full text Add to dashboard Cite

Several genera of oomycete fungi which are incapable of de novo sterol synthesis do not require these compounds for vegetative growth. The requirement for an exogenous source of sterols for sexual reproduction by several members of the Pythiaceae has been questioned by reports of apparent induction and maturation of oospores on defined media supplemented with phospholipids in the absence of sterols. A more detailed examination of this phenomenon suggested that trace levels of sterols in the inoculum of some pythiaceous fungi act synergistically with phospholipid medium supplements containing unsaturated fatty acid moieties to induce oosporogenesis. Phospholipid analysis of one species, Pythium ultimum, suggested that only the fatty acid portion of the exogenous phospholipid is taken up by the fungus. Enrichment of the phospholipid fraction of total cell lipid of P. ultimum with unsaturated fatty acids promoted oospore induction, and enhanced levels of unsaturated fatty acids in the neutral lipid fraction increased oospore viability. For some pythiaceous fungi, the levels of sterols required for the maturation of oospores with appropriate phospholipid medium supplementation suggest that these compounds are necessary only for the sparking and critical domain roles previously described in other fungi.

show abstract

Effects of triarimol and tridemorph on sterol biosynthesis inSaprolegnia ferax

Berg

Patterson

Lusby

1983

Lipids

View full text Add to dashboard Cite

The effects of two fungicides, triarimol and tridemorph, on sterol biosynthesis inSaprolegnia ferax were examined. Cultures grown in the presence of triarimol accumulated lanosterol. Tridemorph‐treated cultures accumulated Δ8‐sterols including zymosterol, fecosterol and stigmasta‐8‐24(28)‐dienol. The latter is a new sterol. A proposed scheme is given for sterol biosynthesis inS. ferax showing points of inhibition of triarimol and tridemorph. Results point to the intermediacy of lanosterol but not cycloartenol in sterol synthesis inSaprolegnia.

show abstract

Evidence for a cycloartenol-based sterol synthetic pathway inLagenidium spp.

Cited by 20 publications

References 19 publications

Cycloartenol-derived sterol biosynthesis in the Peronosporales

Cycloartenol-derived sterol biosynthesis in the Peronosporales

Reassessment of the role of phospholipids in sexual reproduction by sterol-auxotrophic fungi

Effects of triarimol and tridemorph on sterol biosynthesis inSaprolegnia ferax

Contact Info

Product

Resources

About