Requirements of Δ9 and Δ12 fatty acid desaturation in Neurospora

Gabrielides, Christine; Hamill, Anne L.; Scott, William

doi:10.1016/0005-2760(82)90278-8

Cited by 11 publications

(8 citation statements)

References 25 publications

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“…This effect contrasts with observations made in studies of Netlrospora phospholipid composition during temperature changes, in which the amount of 18:2 and 18:3 appear to be controlled independently (Martin et al, 1981). However, the effect resembles one observed for tlfa mutants, which do not desaturate 18 : 0, but may also show impaired 18 : 1 or 18 : 2 desaturation (Scott, 1977b;Gabrielides et al, 1982;Goodrich-Tanrikulu e t al., 1994).…”

Section: Implications For the Control Of Polyunsaturated Fa Biosynthecontrasting

confidence: 56%

“…It is not known which acyl group(s) undergoes the desaturation, and alternative substrates, such as CoA esters, which might be utilized in a minor pathway, have not been ruled out (Baker & Lynen, 1971). Since NADPH biosynthetic mutants have reduced 18 : 3 levels (20 YO of wild-type), it has been postulated that the 18 : 2 desaturase may utilize NADPH preferentially for the desaturation (Brody & Nyc, 1970), whereas the 18: 1 desaturase utilizes NADH (Gabrielides et al, 1982). A small amount of the total 18 : 3 may thus be formed by a second desaturase or using an alternative reductase.…”

Section: Implications For the Control Of Polyunsaturated Fa Biosynthementioning

confidence: 99%

“…Additionally, some biochemical information on the pathway of desaturation in Neurospora is available, and mutants for the desaturation of 18 : 0 to 1 8 : 1 (ufa) (Scott, 1977a ;Goodrich-Tanrikulu e t al., 1994) and for the biosynthesis of PC (chol-I, chol-2) (Horowitz & Beadle, 1943;Horowitz et al, 1945;Scarborough & Nyc, 1967) have been isolated. Mutants defective in the desaturation of 18: 1 or a-18:2 have not been described, aside from reports that mutants defective in the synthesis of NADPH have reduced levels of a-l8 : 3 (Brody & Nyc, 1970;Nyc & Brody, 1971), and that ufa mutants may also be impaired in subsequent desaturation steps (Scott, 1977b ;Gabrielides et al , 1982 ; GoodrichTanrikulu e t a/., 1994).…”

Section: Introductionmentioning

confidence: 99%

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Novel Neurospora crassa mutants with altered synthesis of polyunsaturated fatty acids

et al. 1995

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Five new mutants of Neurospora crassa that require supplementation with unsaturated fatty acids have been isolated. The mutants, designated pfa, are impaired in the synthesis of the polyunsaturated fatty acids a-linoleic or a-linolenic acid, but are able to synthesize oleic acid. The pfa mutants are thus distinct from previously described ufa mutants, which are unable to synthesize oleic acid. The five pfa mutants map to distinct loci, and have characteristic patterns of incorporation of [14C]acetate and [14C]oleate into their fatty acids.

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Section: Implications For the Control Of Polyunsaturated Fa Biosynthecontrasting

confidence: 56%

Section: Implications For the Control Of Polyunsaturated Fa Biosynthementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Novel Neurospora crassa mutants with altered synthesis of polyunsaturated fatty acids

et al. 1995

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“…A third possibility is that the levels of substrates and products, which differ as mentioned above (Figs la, :!a) regulate activity of the desaturases. In wild-type Nezlrospora, excess substrate stimulates stearate desaturase activity in microsomes, and unsaturated products inhibit it (Gabrielides et al, 1982). In Saccharomyes, similar controls operate, with fatty acid composition affecting OLE I transcription, OLE1 mRNA levels, and stearate desaturase activity (McDonough e t al., 1992).…”

Section: Comparison With Previously Identified Ufa Mutantsmentioning

confidence: 99%

“…A similar pleiotropic effect was also noted in a later report of the .fa-I and zlfa-2 mutants. In addition to lacking stearate desaturase activity, zlfa-I was reported to have partial and zlfa-2 complete absence of oleate desaturase activity in isolated microsomes (Gabrielides et al, 1982). It is not clear why results were different: with these mutants when oleate desaturase activities were examined in vivo (Scott, 1977b) and in vitro (Gabrielides e t al., 1982).…”

Section: Comparison With Previously Identified Ufa Mutantsmentioning

confidence: 99%

Fatty acid biosynthesis in novel ufa mutants of Neurospora crassa

Goodrich-Tanrikulu¹,

Stafford²,

Lin³

et al. 1994

Microbiology

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New mutants of Neurospora crassa having the ufa phenotype have been isolated. Two of these mutants, like previously identified ufa mutants, require an unsaturated fatty acid for growth and are almost completely blocked in the de now0 synthesis of unsaturated fatty acids. The new mutations map to a different chromosomal location than previously characterized ufa mutations. This implies that at least one additional genetic locus controls the synthesis of unsaturated fatty acids in Neurospora.

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Incorporation of linoleic acid and its conversion to λ‐linolenic acid in fungi

Kamisaka¹,

Yokochi²,

Nakahara³

et al. 1990

Lipids

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The incorporation of [1‐14C]linoleic acid (LA) into lipids ofMortierella ramanniana var.angulispora was studied to determine which lipid classes participated in the δ6‐desaturation of [1‐14C]LA. [1‐14C]LA was rapidly taken up into fungal cells and esterified into various lipids. Comparison of the profile of [1‐14C]LA incorporation between fungal cells at the exponential growth phase and the stationary growth phase showed that [1‐14C]LA incorporation into most lipids—except for triacylglycerol (TG) and phosphatidylcholine (PC)—were greatly reduced at the stationary growth phase. Desaturation of [1‐14C]LA into λ‐linolenic acid (GLA) readily occurred at the exponential growth phase, but was greatly decreased at the stationary growth phase. Moreover, pulse‐chase experiments revealed that the radiolabel incorporated into phosphatidylserine (PS) and PC rapidly turned over, while that in TG and diacylglycerol (DG) accumulated after the 4 hr chase. In addition to the change of the radiolabel in individual lipids, the content of radiolabeled GLA converted from [1‐14C]LA varied with individual lipids. In phospholipids such as PC, phosphatidylethanolamine (PE) and PS, radiolabeled GLA rapidly increased after 1 hr and then decreased after 4 hr. On the other hand, a gradual increase in radiolabeled GLA until 4 hr was observed in TG. These results suggest that LA, which has been esterified into phospholipids such as PC, PE and PS, is readily desaturated to GLA, which is then transferred to TG. These differences in the fate of GLA derived from LA between phospholipids and neutral lipids may be reflected in the GLA content in the individual lipids.

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Requirements of Δ9 and Δ12 fatty acid desaturation in Neurospora

Cited by 11 publications

References 25 publications

Novel Neurospora crassa mutants with altered synthesis of polyunsaturated fatty acids

Novel Neurospora crassa mutants with altered synthesis of polyunsaturated fatty acids

Fatty acid biosynthesis in novel ufa mutants of Neurospora crassa

Incorporation of linoleic acid and its conversion to λ‐linolenic acid in fungi

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