scholarly journals Induction of Nad-Specific Glutamate Dehydrogenase In Neurospora Crassa by Addition of Glutamate to The Media

1969 ◽  
Vol 22 (2) ◽  
pp. 425 ◽  
Author(s):  
WN Strickland
Keyword(s):  
Neurospora Crassa ◽  
Nitrogen Source ◽  
Glutamate Dehydrogenase ◽  
Inorganic Nitrogen ◽  
The Other ◽  
Wild Type ◽  
Carbon And Nitrogen ◽  
The Media ◽  
Type Strains

There are two glutamate dehydrogenases (GDH) produced by wild-type strains of N. cra88a, one of which is specific for the coenzyme NADP and the other for the coenzyme NAD. The latter enzyme (NAD-GDH) is induced if glutamate is used as the sole carbon and nitrogen source and is induced to a lesser extent if inorganic nitrogen is added. Addition of sucrose to the medium prevents uptake of glutamate and there is no induction of the enzyme.

scholarly journals The effect of thiourea on ureide metabolism in Neurospora crassa

1973 ◽  
Vol 136 (3) ◽  
pp. 749-755 ◽  
Author(s):  
Jasti Nirmala ◽  
Killampalli Sivarama Sastry
Keyword(s):  
Neurospora Crassa ◽  
Nitrogen Source ◽  
Type Strain ◽  
Wild Type Strain ◽  
Inorganic Nitrogen ◽  
Wild Strain ◽  
Sole Nitrogen Source ◽  
Wild Type ◽  
Selective Toxicity ◽  
In The Wild

The wild-type strain of Neurospora crassa Em 5297a can utilize allantoin as a sole nitrogen source. The pathway of allantoin utilization is via its conversion into allantoic acid and urea, followed by the breakdown of urea to ammonia. This is shown by the inability of the urease-less mutant, N. crassa 1229, to grow on allantoin as a sole nitrogen source and by the formation of allantoate and urea by pre-formed mycelia of this mutant. In the wild strain (Em 5297a) thiourea is tenfold more toxic on an allantoin medium than on an inorganic nitrogen medium; allantoin as well as urea counteract thiourea toxicity in the allantoin nitrogen medium. This selective toxicity of thiourea for the mould utilizing allantoin nitrogen does not, however, result in an impairment of allantoin uptake, allantoinase activity or the formation of urea from allantoin. The only process affected by thiourea is the synthesis of urease; urea antagonizes this effect of thiourea in N. crassa.

scholarly journals Mutants affecting histidine utilization inAspergillus nidulans

1975 ◽  
Vol 25 (2) ◽  
pp. 119-135 ◽  
Author(s):  
Meryl Polkinghorne ◽  
M. J. Hynes
Keyword(s):  
Carbon Source ◽  
Nitrogen Source ◽  
Sole Carbon Source ◽  
Nitrogen Sources ◽  
Limiting Factor ◽  
Sole Nitrogen Source ◽  
Wild Type ◽  
Exogenous Substrate ◽  
Growth Properties ◽  
Type Strains

SUMMARYWild-type strains ofAspergillus nidulansgrow poorly onL-histidine as a sole nitrogen source. The synthesis of the enzyme histidase (EC. 4.3.1.3) appears to be a limiting factor in the growth of the wild type, as strains carrying the mutantareA102 allele have elevated histidase levels and grow strongly on histidine as a sole nitrogen source.L-Histidine is an extremely weak sole carbon source for all strains.Ammonium repression has an important role in the regulation of histidase synthesis and the relief of ammonium repression is dependent on the availability of a good carbon source. The level of histidase synthesis does not respond to the addition of exogenous substrate.Mutants carrying lesions in thesarA orsarB loci (suppressor ofareA102) have been isolated. The growth properties of these mutants on histidine as a sole nitrogen source correlate with the levels of histidase synthesized. Mutation at thesarA andsarB loci also reduces the utilization of a number of other nitrogen sources. The data suggest that these two genes may code for regulatory products involved in nitrogen catabolism. No histidase structural gene mutants were identified and possible explanations of this are discussed.

scholarly journals Nitrogen Source Regulates Glutamate Dehydrogenase NADP Synthesis in Neurospora crassa

1983 ◽  
Vol 154 (1) ◽  
pp. 524-528 ◽  
Author(s):  
Georgina Hernández ◽  
Ray Sánchez-Pescador ◽  
Rafael Palacios ◽  
Jaime Mora
Keyword(s):  
Neurospora Crassa ◽  
Nitrogen Source ◽  
Glutamate Dehydrogenase

Catabolite-controlled regulation of glutamate dehydrogenases of Neurospora crassa

1970 ◽  
Vol 16 (1) ◽  
pp. 33-40 ◽  
Author(s):  
M. Kapoor ◽  
A. K. Grover
Keyword(s):  
Neurospora Crassa ◽  
Glutamate Dehydrogenase ◽  
Growth Medium ◽  
Nicotinamide Adenine Dinucleotide ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Reciprocal Relationship ◽  
The Other ◽  
Nicotinamide Adenine ◽  
Specific Enzyme ◽  
Other Hand

The effect of the presence of catabolites in the growth medium on the synthesis of the two glutamate dehydrogenases of Neurospora crassa is reported. It has been demonstrated that the nicotinamide adenine dinucleotide (NAD) specific glutamate dehydrogenase is subject to repression by sucrose and glucose. Nicotinamide adenine dinucleotide phosphate (NADP) specific glutamate dehydrogenase, on the other hand, is induced by increasing concentrations of the catabolite. These data suggest that a reciprocal relationship exists between these two enzymes during synthesis in the presence of catabolites. Growth in higher concentrations of sucrose led to the formation of two isoenzymes of the NADP-specific enzyme; the second or the minor isozyme is not produced at very low catabolite concentrations. The catabolite effects produced by sucrose are overcome by glutamate, if the latter is incorporated into the growth medium. Glutamate represses both the isozymes of NADP-specific enzyme.

Glutamate synthase levels in Neurospora crassa mutants altered with respect to nitrogen metabolism

1981 ◽  
Vol 1 (2) ◽  
pp. 158-164
Author(s):  
N S Dunn-Coleman ◽  
E A Robey ◽  
A B Tomsett ◽  
R H Garrett
Keyword(s):  
Neurospora Crassa ◽  
Glutamate Dehydrogenase ◽  
Nitrogen Metabolism ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Glutamate Synthase ◽  
Wild Type ◽  
Mutant Strains ◽  
Synthase Regulation ◽  
Glutamate Biosynthesis ◽  
Glutamine Limitation

Glutamate synthase catalyzes glutamate formation from 2-oxoglutarate plus glutamine and plays an essential role when glutamate biosynthesis by glutamate dehydrogenase is not possible. Glutamate synthase activity has been determined in a number of Neurospora crassa mutant strains with various defects in nitrogen metabolism. Of particular interest were two mutants phenotypically mute except in an am (biosynthetic nicotinamide adenine dinucleotide phosphate-glutamate dehydrogenase deficient, glutamate requiring) background. These mutants, i and en-am, are so-called enhancers of am; they have been redesignated herein as en(am)-1 and en(am)-2, respectively. Although glutamate synthase levels in en(am)-1 were essentially wild type, the en(am)-2 strain was devoid of glutamate synthase activity under all conditions examined, suggesting that en(am)-2 may be the structural locus for glutamate synthase. Regulation of glutamate synthase occurred to some extent, presumably in response to glutamate requirements. Glutamate starvation, as in am mutants, led to enhanced activity. In contrast, glutamine limitation, as in gln-1 mutants, depressed glutamate synthase levels.

Isolation of telomere DNA from Neurospora crassa

1987 ◽  
Vol 7 (9) ◽  
pp. 3168-3177
Author(s):  
M G Schechtman
Keyword(s):  
Linkage Group ◽  
Neurospora Crassa ◽  
Genetic Background ◽  
Type Strain ◽  
Wild Type Strain ◽  
The Other ◽  
Wild Type ◽  
Oak Ridge ◽  
Entire Chromosome ◽  
Different Genetic Background

The most distal known gene on Neurospora crassa linkage group VR, his-6, was cloned. A genomic walk resulted in isolation of the telomere at VR. It was obtained from a library in which the endmost nucleotides of the chromosome had not been removed by nuclease treatment before being cloned, and mapping indicates that the entire chromosome end has probably been cloned. Sequences homologous to the terminal 2.5 kilobases of DNA from VR from these Oak Ridge N. crassa strains are found at other sites in the genome. To characterize these sites, I crossed an Oak Ridge-derived his-6 strain with a wild-type strain of different genetic background (Mauriceville) and characterized the hybridization patterns seen in the progeny. It appears that the sequences homologous to the VR terminus are found at genetically different sites in the two parental strains, and no hybridization to the VR telomere from Mauriceville was detected. The other genomic copies identified in the Oak Ridge parent were not telomeres. I suggest that any repeating sequence blocks found immediately adjacent to the VR terminus in Oak Ridge strains must be small and that the repeating element identified in that background may be an N. crassa transposable element integrated near the the chromosome end at VR.

scholarly journals Immunological identification of the alternative oxidase of Neurospora crassa mitochondria.

1989 ◽  
Vol 9 (3) ◽  
pp. 1362-1364 ◽  
Author(s):  
A M Lambowitz ◽  
J R Sabourin ◽  
H Bertrand ◽  
R Nickels ◽  
L McIntosh
Keyword(s):  
Neurospora Crassa ◽  
Oxidase Activity ◽  
Hydroxamic Acid ◽  
Alternative Oxidase ◽  
Fungal Species ◽  
The Other ◽  
Wild Type ◽  
Higher Plant ◽  
Sauromatum Guttatum ◽  
Immunological Identification

Neurospora crassa mitochondria use a branched electron transport system in which one branch is a conventional cytochrome system and the other is an alternative cyanide-resistant, hydroxamic acid-sensitive oxidase that is induced when the cytochrome system is impaired. We used a monoclonal antibody to the alternative oxidase of the higher plant Sauromatum guttatum to identify a similar set of related polypeptides (Mr, 36,500 and 37,000) that was associated with the alternative oxidase activity of N. crassa mitochondria. These polypeptides were not present constitutively in the mitochondria of a wild-type N. crassa strain, but were produced in high amounts under conditions that induced alternative oxidase activity. Under the same conditions, mutants in the aod-1 gene, with one exception, produced apparently inactive alternative oxidase polypeptides, whereas mutants in the aod-2 gene failed to produce these polypeptides. The latter findings support the hypothesis that aod-1 is a structural gene for the alternative oxidase and that the aod-2 gene encodes a component that is required for induction of alternative oxidase activity. Finally, our results indicate that the alternative oxidase is highly conserved, even between plant and fungal species.

scholarly journals Glutamate synthase levels in Neurospora crassa mutants altered with respect to nitrogen metabolism.

1981 ◽  
Vol 1 (2) ◽  
pp. 158-164 ◽  
Author(s):  
N S Dunn-Coleman ◽  
E A Robey ◽  
A B Tomsett ◽  
R H Garrett
Keyword(s):  
Neurospora Crassa ◽  
Glutamate Dehydrogenase ◽  
Nitrogen Metabolism ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Glutamate Synthase ◽  
Wild Type ◽  
Mutant Strains ◽  
Synthase Regulation ◽  
Glutamate Biosynthesis ◽  
Glutamine Limitation

Glutamate synthase catalyzes glutamate formation from 2-oxoglutarate plus glutamine and plays an essential role when glutamate biosynthesis by glutamate dehydrogenase is not possible. Glutamate synthase activity has been determined in a number of Neurospora crassa mutant strains with various defects in nitrogen metabolism. Of particular interest were two mutants phenotypically mute except in an am (biosynthetic nicotinamide adenine dinucleotide phosphate-glutamate dehydrogenase deficient, glutamate requiring) background. These mutants, i and en-am, are so-called enhancers of am; they have been redesignated herein as en(am)-1 and en(am)-2, respectively. Although glutamate synthase levels in en(am)-1 were essentially wild type, the en(am)-2 strain was devoid of glutamate synthase activity under all conditions examined, suggesting that en(am)-2 may be the structural locus for glutamate synthase. Regulation of glutamate synthase occurred to some extent, presumably in response to glutamate requirements. Glutamate starvation, as in am mutants, led to enhanced activity. In contrast, glutamine limitation, as in gln-1 mutants, depressed glutamate synthase levels.

scholarly journals The Escherichia coli gabDTPC Operon: Specific γ-Aminobutyrate Catabolism and Nonspecific Induction

2002 ◽  
Vol 184 (24) ◽  
pp. 6976-6986 ◽  
Author(s):  
Barbara L. Schneider ◽  
Stephen Ruback ◽  
Alexandros K. Kiupakis ◽  
Hillary Kasbarian ◽  
Christine Pybus ◽  
...  
Keyword(s):  
Nitrogen Source ◽  
Nitrogen Limitation ◽  
Nitrogen Sources ◽  
Wild Type ◽  
Gaba A ◽  
Specific Induction ◽  
Related Compounds ◽  
Type Strains

ABSTRACT Nitrogen limitation induces the nitrogen-regulated (Ntr) response, which includes proteins that assimilate ammonia and scavenge nitrogen. Nitrogen limitation also induces catabolic pathways that degrade four metabolically related compounds: putrescine, arginine, ornithine, and γ-aminobutyrate (GABA). We analyzed the structure, function, and regulation of the gab operon, whose products degrade GABA, a proposed intermediate in putrescine catabolism. We showed that the gabDTPC gene cluster constitutes an operon based partially on coregulation of GabT and GabD activities and the polarity of an insertion in gabT on gabC. A ΔgabDT mutant grew normally on all of the nitrogen sources tested except GABA. The unexpected growth with putrescine resulted from specific induction of gab-independent enzymes. Nac was required for gab transcription in vivo and in vitro. Ntr induction did not require GABA, but various nitrogen sources did not induce enzyme activity equally. A gabC (formerly ygaE) mutant grew faster with GABA and had elevated levels of gab operon products, which suggests that GabC is a repressor. GabC is proposed to reduce nitrogen source-specific modulation of expression. Unlike a wild-type strain, a gabC mutant utilized GABA as a carbon source and such growth required σS. Previous studies showing σS-dependent gab expression in stationary phase involved gabC mutants, which suggests that such expression does not occur in wild-type strains. The seemingly narrow catabolic function of the gab operon is contrasted with the nonspecific (nitrogen source-independent) induction. We propose that the gab operon and the Ntr response itself contribute to putrescine and polyamine homeostasis.

scholarly journals GENETIC AND PHYSIOLOGICAL CHARACTERISTICS OF A SLOW-GROWING CIRCADIAN CLOCK MUTANT OF NEUROSPORA CRASSA

Genetics ◽  
1978 ◽  
Vol 88 (2) ◽  
pp. 255-265
Author(s):  
Jerry F Feldman ◽  
Cheryl A Atkinson
Keyword(s):  
Linkage Group ◽  
Circadian Clock ◽  
Neurospora Crassa ◽  
Double Mutant ◽  
Slow Growth ◽  
Period Length ◽  
The Other ◽  
Wild Type ◽  
Long Period ◽  
Clock Mutant

ABSTRACT A circadian clock mutant of Neurospora crassa with a period length of about 25.8 hours (4 hr longer than wild type) has been isolated after mutagenesis of the band strain. This mutant, called frq-5, segregates as a single nuclear gene, maps near the centromere on linkage group III, and is unlinked to four previously described clock mutants clustered on linkage group VII R (Feldman and Hoyle 1973, 1976). frq-5 differs from the other clock mutants in at least two other respects: (1) it is recessive in heterokaryons, and (2) it grows at about 60% the rate of the parent band strain on both minimal and complete media. Double mutants between frq-5 and each of the other clock mutants show additivity of period length-two long period mutants produce a double mutant whose period length is longer than either of the two single mutants, while a long and a short period double mutant has an intermediate period length. Although slow growth and long periodicity of frq-5 have segregated together among more than 300 progeny, slow growth per se is not responsible for the long period, since all the double mutants have the slow growth characteristic of frq-5, but have period lengths both shorter and longer than wild type.

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