A systematic survey of the fatty acid composition of Neurospora strains

Numerous studies have examined aspects of lipid metabolism in Neurospora crassa, N. tetrasperma and N. sitophila, but little systematic comparison has been done on lipids of the different species. Most obviously missing, however, is comparison of the fatty acid composition of lipids among Neurospora species. Fatty acid composition (especially the production of particular polyunsaturated fatty acids) is often a key factor in genus or species identification, particularly in bacteria, but also in other fungi such as Aspergillus, Penicillium and Mortierella (Kock and Botha 1998 In Frisvad et al. (eds), Chemical Fungal Taxonomy, Marcel Dekker, NY, p. 219-246). Until this study, reports of the fatty acid composition of Neurospora lipids have been limited to a few laboratory strains of N. crassa

Isotope discrimination by the stearoyl desaturase of Neurospora crassa

In wild type Neurospora crassa, we previously observed an unexpectedly low proportion of label in unsaturated fatty acids that should have been derived from deuterated palmitate (16:0). Interpretation of whether the position of deuteration could account for these results was inconclusive, because wild type had a low proportion of total fatty acids derived from the deuterated supplement. The N. crassa cel-1 strain is ideally suited for studies of fatty acid enrichment, because cel-1 must obtain its fatty acids exogenously. We supplemented cel-1 with 16:0\u27s deuterated at different positions. With each of the labelled 16:0\u27s, cel-1 desaturated the stearate (18:0) derived from the 16:0 more efficiently than wild type. However, when the 16:0 was deuterated at the site of future desaturation, we indeed observed effects on fatty acid composition and label distribution consistent with inhibition of the 18:0 desaturase

Light regulation of metabolic pathways in fungi

Light represents a major carrier of information in nature. The molecular machineries translating its electromagnetic energy (photons) into the chemical language of cells transmit vital signals for adjustment of virtually every living organism to its habitat. Fungi react to illumination in various ways, and we found that they initiate considerable adaptations in their metabolic pathways upon growth in light or after perception of a light pulse. Alterations in response to light have predominantly been observed in carotenoid metabolism, polysaccharide and carbohydrate metabolism, fatty acid metabolism, nucleotide and nucleoside metabolism, and in regulation of production of secondary metabolites. Transcription of genes is initiated within minutes, abundance and activity of metabolic enzymes are adjusted, and subsequently, levels of metabolites are altered to cope with the harmful effects of light or to prepare for reproduction, which is dependent on light in many cases. This review aims to give an overview on metabolic pathways impacted by light and to illustrate the physiological significance of light for fungi. We provide a basis for assessment whether a given metabolic pathway might be subject to regulation by light and how these properties can be exploited for improvement of biotechnological processes