Neurospora crassa system

Effects of Allelochemlcals on ATPases. Several flavonoid compounds inhibit ATPase activity that is associated with mineral absorption. Phloretin and quercetin (100 pM) inhibited the plasma membrane ATPase Isolated from oat roots (33). The naphthoquinone juglone was inhibitory also. However, neither ferulic acid nor salicylic acid inhibited the ATPase. Additional research has shown that even at 10 mM salicylic acid inhibits ATPase activity only 10-15% (49). This lack of activity by salicylic acid was substantiated with the plasma membrane ATPase Isolated from Neurospora crassa (50) however, the flavonols fisetln, morin, myricetin, quercetin, and rutin were inhibitory to the Neurospora ATPase. Flavonoids inhibited the transport ATPases of several animal systems also (51-53). Thus, it appears that flavonoids but not phenolic acids might affect mineral transport by inhibiting ATPase enzymes. 

Relationships between the structure of the siderophores and the iron transport were investigated for the fungus Neurospora crassa (160, 160a). Apparently two different receptors exist for ferrichromes and for coprogenes. For the recognition and the binding to the cell surface the iron configuration and the nature of the acyl chains is of importance. However, the transport system seems to be the same for both siderophore types dependent on the peptide part of the molecules. 

Enzyme Systems. Carotenoid biosynthesis by crude cell-free preparations from Halobacterium cutirubrum 0-carotene), Phycomyces blakesleeanus mutants (/8-carotene), and a Neurospora crassa mutant (phytoene) has been demonstrated. Detailed studies of carotenogenic enzymes from tomato fruit... 

Light is a major regulatory influence on carotenoid synthesis in many plant and microbial systems. A review of this photoregulation has been published. Other papers report the photoinduction of the biosynthesis of phytoene and other carotenoids in strains of Neurospora crassa. " ... 

Neurospora crassa are deficient in a high-affinity phosphate transport system. J. Bacteriol. 153 292-296. 

Bowman, B.J. 1983. Vanadate uptake in Neurospora crassa occurs via phosphate transport system II. J. Bacteriol. 153 286-291. 

Fungi Mutation Neurospora crassa ad-3 system red adenine mutants Gene (forward) mutations and small deletions in ad3A and ad3B <2 mo M M M L... 

Ong, T-M. Use of the spot, plate and suspension test systems for the detection of the mutagenicity of environmental agents and chemical carcinogens in Neurospora crassa. Mutat. Res. 53 297-308, 1978. 

A few examples include the mouse specific-locus test for germ-cell mutagenesis (Russell 1994 Russell 1989), tests for forward and reverse mutations in the ad-3 region of Neurospora crassa (de Serres and Kolmark 1958), the Tradescantia stamen-hair system (Underbrink et al. 1973), and the rlllocus test for bacteriophage T4 (Drake 1963). Many others could be noted. 

Nitrite reduction in assimilatory nitrate-reducing Neurospora crassa, Torulopsis nitratophila, Azotobacter vinelandii, and Azotobacter chro-ococcum appears to be catalyzed by enzyme systems which require flavin and metals. The enzyme from N. crassa has been partially purified, and its molecular weight has been estimated to be 300,000 (344, 346, 351, 367). The enzyme reduces both nitrite and hydroxylamine to ammonia and utilizes NADH or NADPH as electron donor. It is reported to be a FAD-dependent enzyme and to contain iron, copper, and active thiol (346, 367). Three moles of NADH are oxidized per mole of nitrite reduced to ammonia. It has been suggested that the reduction of nitrite occurs in three steps, each involving two electrons. Thus, hyponitrite and hydroxylamine have been proposed as successive intermediates in the re-... 

Enzyme Systems. A crude enzyme system from Neurospora crassa has been described which incorporates isopentenyl pyrophosphate into phytoene (15). The only absolute cofactor requirement is for Mg. ... 

The method of biosynthetic incorporation of spin label, rather than mechanical addition to isolated material, is a convenient way of ensuring that the results obtained are biologically meaningful and has also been used with such systems as the mould Neurospora crassa [158], Mycoplasma laidlawii [159], human leucocytes, and mouse L cells [160]. The spectra from these two mammalian cells showed distinct similarities for a variety of spin labels, but different spectra were obtained when the labels were incorporated in human erythrocytes. Fractionation of the cell components showed the stearic acid (C, n = 3) spin label in all the major fractions, but by far the largest concentration was in the nuclear membrane. The ESR spectrum underwent a time and temperature dependent decay and spin labels on the surface membrane were reactivated with K3Fe(CN)6. 

NDMA is mutagenic for Escherichia coli, Salmonella typhimurium, and Neurospora crassa. It can produce mitotic recombination in Sacharoyus cerevesiae species, recessive lethal mutations in Drosophilla melanogaster, and chromosomal aberrations in mammalian cells. Mutagenic responses in bacterial cells are dependent upon the addition of a mammalian drug metabolism system (specific form of cytochrome P450). 

Neurospora crassa (whole cell system NADH provides reducing power)... 

The existence of a mitochondrial pathway for de novo fatty acid synthesis was first reported 50 years ago, when it was generally assumed that fatty acid synthesis proceeded by reversal of the mitochondrial pathway for fatty acid P-oxidation (F. Lynen, 1957). However, the discovery of the cytosolic malonyl-CoA pathway (R.O. Brady, 1958 S.J Wakil, 1958) casted doubt on these claims and interest in this system waned until the discovery that mitochondria of both Neurospora crassa and Saccharomyces cerevisiae contain nuclear-encoded mitochondrial proteins that function as a type II FAS system. Disruption of the genes encoding these enzymes in both N. crassa and S. cerevisiae produces respiratory-deficient phenotypes and in S. cerevisiae cellular lipoic acid is reduced to less than 10% of that of the wild-type strain (R. Schneider, 1995 E. Schweizer, 1997). These observations suggested that in fungi one of the roles of this pathway might be to generate the lipoyl moieties required for mitochondrial function. 

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