排序方式: 共有13条查询结果,搜索用时 187 毫秒
1.
A cell extract of the yellow C115 car-42 mad-107(?) mutant of Phycomyces blakesleeanus, capable of converting MVA-[2-14C] into isoprenoids, was used to investigate the formation of β-carotene. The incorporation of radioactivity into β-carotene was reduced by the addition of unlabelled carotenes, solubilised using detergent, to the incubation mixtures. On reisolation of these carotenes after anaerobic incubations, they were found to carry radioactivity. The relative efficiencies of these carotenes as trapping agents are discussed in relation to the pathways of carotene cyclisation and to the apparent operation of a system for the negative feedback control of carotene biosynthesis. 相似文献
2.
Ergosterol, episterol, 4α-methyl-5α-ergosta-8,24(28)-dien-3β-ol and 24-methylene-24,25-dihydrolanosterol, isolated from Phycomyces blakesleeanus grown in the presence of methionine-[methyl-2H3], each contained two deuterium atoms; lanosterol, however, was unlabelled. The 14C:3H atomic ratio of the following sterols isolated from P. blakesleeanus grown in the presence of mevalonic acid-[2-14C,(4R)-4-3H1], was: ergosterol, 5:3; episterol, 5:4; ergosta-5,7,24(28)-trien-3β-ol, 5:3; 4α-methyl-5α-ergosta-8,24(28)-dien-3β-ol, 5:4; 24-methylene-24,25-dihydrolanosterol, 6:5; lanosterol, 6:5. The significance of these results in terms of ergosterol biosynthesis is discussed. 相似文献
3.
The following sterols have been isolated from the fungi, Phycomyces blakesleeanus and Agaricus campestris: ergosterol, lanosterol, 24-methylene-24,25-dihydrolanosterol and episterol. 4,4-Dimethyl-5α-ergosta-8.24(28)-dien-3β-ol and 4α-methyl-5α-ergosta-8,24(28)-dien-3β-ol have been tentatively identified. Evidence for the incorporation of label from l-methionine-[methyl-14C] into some of these sterols in P. blakesleeanus has been obtained. The significance of these sterols in ergosterol biosynthesis is discussed. 相似文献
4.
In Phycomyces blakesleeanus the total level of free amino acids and their relative distributions change strikingly during the development of sporangiophores. Very high levels of serine, glutamate and histidine are found. The variety of amino acids becomes more restricted in sporangiophores grown on nitrogen-rich media; levels of arginine increase dramatically. The distribution differs in mycelia. No unusual amino acids or oligopeptides were found. 相似文献
5.
Comparisons of the fatty acid composition of the sterol esters, triglycerides and phospholipids and the sterol composition of the esterified and uneste 相似文献
6.
A cell-free enzyme preparation of P. blakesleeanus has been shown to possess phosphatidylcholine: sterol acyltransferase, sterol ester hydrolase an 相似文献
7.
Ergosterol, 22-dihydroergosterol, obtusifoliol and 24-methylene-24,25-dihydrolanosterol, isolated from Mucor pusillus grown in the presence of methionine-[methyl-2H3], each contained two deuterium atoms; lanosterol, however, was unlabelled. Ergosterol and 22-dihydroergosterol, isolated from M. pusillus grown in the presence of mevalonic acid-[2-14C, (4R)-4-3H1] had 14C:3H atomic ratios of 5:3. The significance of these results in terms of sterol biosynthesis in this organism in general and alkylation at C-24 in particular is discussed. 相似文献
8.
Jennifer Jennessen Johan Schnürer Johan Olsson Robert A. Samson Jan Dijksterhuis 《Mycological Research》2008,112(5):547-563
The fungus Rhizopus oligosporus (R. microsporus var. oligosporus) is traditionally used to make tempe, a fermented food based on soybeans. Interest in the fungus has steadily increased, as it can also ferment other substrates, produce enzymes, and treat waste material. R. oligosporus belongs to the R. microsporus group consisting of morphologically similar taxa, which are associated with food fermentation, pathogenesis, or unwanted metabolite production (rhizonins and rhizoxins). The ornamentation pattern, shape, and size of sporangiospores of 26 R. microsporus group strains and two R. oryzae strains were studied using low-temperature SEM (LT-SEM) and LM. This study has shown that: (1) LT-SEM generates images from well-conserved sporangiophores, sporangia, and spores. (2) Robust spore ornamentation patterns can be linked to all different taxa of the R. microsporus group, some previously incorrectly characterized as smooth. Ornamentation included valleys and ridges running in parallel, granular plateaus, or smooth polar areas. Distribution of ornamentation patterns was related to spore shape, which either was regular, ranging from globose to ellipsoidal, or irregular. Specific differences in spore shape, size, and ornamentation were observed between Rhizopus taxa, and sometimes between strains. (3) R. oligosporus has a defect in the spore formation process, which may be related to the domesticated nature of this taxon. It had a high proportion, 10–31 %, of large and irregular spores, and was significantly differentiated from other, natural Rhizopus taxa as evaluated with partial least squares discriminant analysis. It is remarkable that the vehicle of distribution, the sporangiospore, is affected in the strains that are distributed by human activity. This provides information about the specificity and speed of changes that occur in fungal strains because of their use in (food) industry. 相似文献
9.
W. L. Gauger 《Sexual plant reproduction》1990,3(1):31-34
Summary Auxotrophic strains of Mucor genevensis and Zygorhynchus exponens were crossed and the resulting zygospores germinated. The presence of a true sexual cycle in both species was demonstrated by the recovery of recombinant genotypes. Expected Mendelian ratios were not realized, however. The presence of selfed zygospores among those isolated makes this observation understandable. It was possible to demonstrate nutritional complementation when young mating mycelium was transferred to minimal medium and forced heterokaryons were recovered. 相似文献
10.
Cell extracts capable of converting MVA-[2-14C] into isoprenoids were obtained from the yellow C115-mad-107(−) and red C9-carR21(−) mutants of Phycomyces blakesleeanus. Neither air nor light was essential for carotene biosynthesis. The specific activities of the terpenoid-synthesizing enzymes varied with the age of the cultures although the formation of lycopene (ψ,ψ-carotene) in the C9 and of β-carotene (β,β-carotene) in the C115 'mutants. respectively, followed the increase in the dry weight yield of the cultures. The significance of these results to the biosynthesis of carotenes and to the classification of these compounds as secondary metabolites is discussed. 相似文献