Enzyme activities during the asexual cycle of Neurospora crassa. III. Nicotinamide adenosine diphosphate glycohydrolase

1969 ◽  
Vol 15 (11) ◽  
pp. 1249-1254 ◽  
Author(s):  
G. J. Stine
Keyword(s):  
Neurospora Crassa ◽  
Growth Medium ◽  
Mycelial Growth ◽  
Specific Activity ◽  
Adenosine Diphosphate ◽  
Water Soluble ◽  
Wild Type ◽  
Liquid Environment ◽  
Normal Differentiation ◽  
Asexual Cycle

The level and specific activity of nicotinamide adenosine diphosphate glycohydrolase (NADase) were followed throughout the asexual cycle in Neurospora crassa. A large quantity of NADase associated with the conidia was water soluble. NADase activity rapidly disappeared from the growth medium during conidial germination and from early logarithmic mycelial growth. As the mycelia aged, the enzyme accumulated in the growth medium and in the aging aconidial conidiophores, regardless of their inability to produce conidia. Since the enzyme was synthesized as the culture aged, it appears that the conidiophores age quickly with respect to their production of NADase. Conidia produced from conidiophores of the wild-type culture contained about the same quantity of NADase as the inoculum conidia. The accumulation of NADase in the conidia of wild-type Neurospora is due to the normal differentiation of these conidia in the absence of a liquid environment. The enzyme becomes locked into the conidia being differentiated from conidiophores that contain large amounts of the NADase activity.

scholarly journals Mutation in neurospora crassa with leaf extract of citrus aurantifolia and their soluble protein content

1970 ◽  
Vol 19 (2) ◽  
pp. 151-155
Author(s):  
Apurba Lal Ray ◽  
Mahbuba Akhter Jahan ◽  
Tahsina Rahim
Keyword(s):  
Neurospora Crassa ◽  
Protein Content ◽  
Soluble Protein ◽  
Mycelial Growth ◽  
Leaf Extract ◽  
Mutagenic Effect ◽  
Wild Type ◽  
Soluble Protein Content ◽  
Citrus Aurantifolia ◽  
Morphological Mutants

Leaf extract of Citrus aurantifolia exhibited remarkable inhibitor effect on the radial mycelial growth of Neurospora crassa. The extract also showed mutagenic effect and atleast six morphological mutants of the fungus were detected including albino (al 243), vigorous (vg 117), fluffy (fl 220), colonial (cl 232), conidial band (con. band 171) and dirty (dir 83). The mutants were used for estimation of soluble protein in comparison with the wild type (Ema). The soluble protein content increased to some extent in case of the mutants con. band 171 (192.86 μg/ml), cl 232 (188.57 μg/ml) and vg 117 (186.43 μg/ml) as compared to the wild type (182.14 μg/ml). On the other hand, the soluble protein content was remarkably decreased in case of the mutant al 243 (94.28 μg/ml), which was about 50% less than the control. This indicates that the leaf extract not only effect colony morphology but possesses profound effect on growth and metabolism of the fungus. Key words: Neurospora crassa; Mutation; Leaf extract; Soluble protein DOI: http://dx.doi.org/10.3329/dujbs.v19i2.8958 DUJBS 2010; 19(2): 151-155

ENZYME ACTIVITIES DURING THE ASEXUAL CYCLE OF NEUROSPORA CRASSA: I. SUCCINIC DEHYDROGENASE

1967 ◽  
Vol 13 (9) ◽  
pp. 1203-1210 ◽  
Author(s):  
G. J. Stine
Keyword(s):  
Neurospora Crassa ◽  
Enzyme Activities ◽  
Soluble Protein ◽  
Mycelial Growth ◽  
Germ Tube ◽  
Succinic Dehydrogenase ◽  
Growth Yield ◽  
Conidial Germination ◽  
Germination And Growth ◽  
Asexual Cycle

Separate extracts of Neuorospora crassa grown either in Vogel's medium N, medium N + glutamate, or medium N which had been made deficient in zinc, were assayed for succinic dehydrogenase and soluble protein at intervals throughout the asexual cycle. Succinic dehydrogenase, although apparently unnecessary for either the formation of conidia or conidial germination, does appear to be necessary for mycelial growth and for the production of conidiophores. Differences in the amount of enzyme during morphologically distinct states of differentiation (i.e. production of the germ tube and production of the conidiophore) may serve as an indicator of significant changes in the physiology of Neurospora at these times during development.The level of succinic dehydrogenase in the conidiophore before its differentiation into conidia appears to influence the amount of this enzyme found in the conidia. This is in keeping with the idea that conditions prevailing in the cytoplasm before the formation of conidia may directly influence the constituents subsequently found in the conidia which determine conidial viability, rate of germination, and growth yield.

scholarly journals Characterization of rco-1 of Neurospora crassa, a pleiotropic gene affecting growth and development that encodes a homolog of Tup1 of Saccharomyces cerevisiae.

1996 ◽  
Vol 16 (11) ◽  
pp. 6218-6228 ◽  
Author(s):  
C T Yamashiro ◽  
D J Ebbole ◽  
B U Lee ◽  
R E Brown ◽  
C Bourland ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Neurospora Crassa ◽  
Transcriptional Repression ◽  
Mycelial Growth ◽  
Regulatory Region ◽  
Selection Strategy ◽  
Wild Type ◽  
Reading Frame ◽  
Growth Selection ◽  
Pleiotropic Gene

The filamentous fungus Neurospora crassa undergoes a well-defined developmental program, conidiation, that culminates in the production of numerous asexual spores, conidia. Several cloned genes, including con-10, are expressed during conidiation but not during mycelial growth. Using a previously described selection strategy, we isolated mutants that express con-10 during mycelial growth. Selection was based on expression of an integrated DNA fragment containing the con-10 promoter-regulatory region followed by the initial segment of the con-10 open reading frame fused in frame with the bacterial hygromycin B phosphotransferase structural gene (con10'-'hph). Resistance to hygromycin results from mutational alterations that allow mycelial expression of the con-10'-'hph gene fusion. A set of drug-resistant mutants were isolated; several of these had abnormal conidiation phenotypes and were trans-acting, i.e., they allowed mycelial expression of the endogenous con-10 gene. Four of these had alterations at a single locus, designated rco-1 (regulation of conidiation). Strains with the rco-1 mutant alleles were aconidial, female sterile, had reduced growth rates, and formed hyphae that coiled in a counterclockwise direction, opposite that of the wild type. The four rco-1 mutants had distinct conidiation morphologies, suggesting that conidiation was blocked at different stages. Wild-type rco-1 was cloned by a novel procedure employing heterokaryon-assisted transformation and ligation-mediated PCR. The predicted RCO1 polypeptide is a homolog of Tup1 of Saccharomyces cerevisiae, a multidomain protein that mediates transcriptional repression of genes concerned with a variety of processes. Like tup1 mutants, null mutants of rco-1 are viable and pleiotropic. A promoter element was identified that could be responsible for RCO1-mediated vegetative repression of con-10 and other conidiation genes.

Inhibition of Mycelial Growth by Methotrexate in Neurospora crassa Wild Type and Mutants Deficient in Folylpolyglutamate Synthase

Pteridines ◽  
1998 ◽  
Vol 9 (4) ◽  
pp. 181-191
Author(s):  
Rebecca E. Wrishko ◽  
Edwin A. Cossins
Keyword(s):  
Neurospora Crassa ◽  
Dihydrofolate Reductase ◽  
Mammalian Cells ◽  
Mycelial Growth ◽  
Gel Filtration ◽  
Wild Type ◽  
Inhibition Of Growth ◽  
Apparent Homogeneity ◽  
Low Levels ◽  
Free Media

Summary In mammalian cells, folylpolyglutamate synthase (FPGS) catalyzes the polyglutamylation of methotrexate (MTX), a reaction that significantly enhances the cellular retention and cytotoxicity of this antifolate. In contrast, MTX is a poor substrate for the cytosolic FPGS of Neurospora crassa. The present study has therefore examined the effect of MTX on growth of N. crassa wild type (FGSC 853 ) and two mutants (met-6, FGSC 1330 and mac, FGSC 3609) that have lesions affecting FPGS expression. Mycelial dry weights after growth in MTX-supplemented media, suggested that met-6 and mac were more sensitive to the antifolate than the wild type (WT). MTX concentrations resulting in 50% inhibition of growth (ICso values) were 5.5 11M, 6.0 11M and 87.5 11M for met-6, mac, and WT, respectively. When MTX treatment was followed by transfer to 50 11M folinic acid-supplemented media, growth of both mutants was enhanced by ca. 20% while that of WT increased by ca. 8%. [3H]-MTX pulse-chase experiments demonstrated that all three strains had limited or no ability to form polyglutamates (MTXGlun ) of the antifolate. In WT cultures, supplied with 1 I-tM [3H]-MTX for 24 hr and then grown in MTX-free media for another 24 hr, over 95% of the recovered label was in MTX; MTXGlu2 and MTXGlu3 accounting for only 2% and 1% respectively. MTXGlun derivatives were not detected in mac but low levels of MTXGlu2 were generated by met-6. In all three strains, the level of expression of dihydrofolate reductase (DHFR) was similar. DHFR was purified to apparent homogeneity (21.6 kDa) from extracts of each strain using a protocol of ammonium sulfate fractionation, gel filtration and Matrex Green A chromatography. It is concluded that in Neurospora, MTX polyglutamylation is not a major factor in the cytotoxicity of this antifolate.

scholarly journals ENZYME ACTIVITIES DURING THE ASEXUAL CYCLE OF NEUROSPORA CRASSA

1968 ◽  
Vol 37 (1) ◽  
pp. 81-88 ◽  
Author(s):  
G. J. Stine
Keyword(s):  
Neurospora Crassa ◽  
Mycelial Growth ◽  
Germ Tube ◽  
Enzyme Synthesis ◽  
Nicotinamide Adenine ◽  
Glutamic Dehydrogenase ◽  
Specific Activities ◽  
Early Phases ◽  
Asexual Cycle ◽  
Logarithmic Growth

Three enzymes, (a) nicotinamide adenine diphosphate-dependent glutamic dehydrogenase (NAD enzyme), (b) nictoinamide adenine triphosphate-dependent glutamic dehydrogenase (NADP enzyme), and (c) nicotinamide-adenine dinucleotidase (NADase), were measured in separate extracts of Neurospora crassa grown in Vogel's medium N and medium N + glutamate. Specific activities and total units per culture of each enzyme were determined at nine separate intervals phased throughout the asexual cycle. The separate dehydrogenases were lowest in the conidia, increased slowly during germination, and increased rapidly during logarithmic mycelial growth. The amounts of these enzymes present during germination were small when compared with those found later during the production of the conidiophores. The NAD enzyme may be necessary for pregermination synthesis. The NADP-enzyme synthesis was associated with the appearance of the germ tube. Although higher levels of the dehydrogenases in the conidiophores resulted in more enzyme being found in the differentiated conidia, the rate of germination was uneffected. The greatest activity for the NADase enzyme was associated with the conidia, early phases of germination, and later production of new conidia. NADase decreased significantly with the onset of logarithmic growth, remained low during the differentiation of conidiophores, and increased considerably as the conidiophores aged.

Ultrastructure and Morphology of the Neurospora Crassa Cell Wall Mutants, Slime And Slime X, Using Tem and Sem

1976 ◽  
Vol 34 ◽  
pp. 54-55
Author(s):  
Karen S. Howard ◽  
H. D. Braymer ◽  
M. D. Socolofsky ◽  
S. A. Milligan
Keyword(s):  
Cell Wall ◽  
Neurospora Crassa ◽  
Wild Type ◽  
Morphological Comparison ◽  
Small Areas ◽  
Solid Media ◽  
Thin Sectioning ◽  
X Cells ◽  
Mutant Cells ◽  
Isolated Cell

The recently isolated cell wall mutant slime X of Neurospora crassa was prepared for ultrastructural and morphological comparison with the cell wall mutant slime. The purpose of this article is to discuss the methods of preparation for TEM and SEM observations, as well as to make a preliminary comparison of the two mutants.TEM: Cells of the slime mutant were prepared for thin sectioning by the method of Bigger, et al. Slime X cells were prepared in the same manner with the following two exceptions: the cells were embedded in 3% agar prior to fixation and the buffered solutions contained 5% sucrose throughout the procedure.SEM: Two methods were used to prepare mutant and wild type Neurospora for the SEM. First, single colonies of mutant cells and small areas of wild type hyphae were cut from solid media and fixed with OSO4 vapors similar to the procedure used by Harris, et al. with one alteration. The cell-containing agar blocks were dehydrated by immersion in 2,2-dimethoxypropane (DMP).

scholarly journals DIRECT INDUCTION IN WILD-TYPE NEUROSPORA CRASSA OF MUTANTS (qa-1C) CONSTITUTIVE FOR THE CATABOLISM OF QUINATE AND SHIKIMATE

Genetics ◽  
1972 ◽  
Vol 72 (3) ◽  
pp. 411-417
Author(s):  
C W H Partridge ◽  
Mary E Case ◽  
Norman H Giles
Keyword(s):  
Neurospora Crassa ◽  
Single Gene ◽  
Ultra Violet ◽  
Wild Type ◽  
Color Test ◽  
Catabolic Enzymes ◽  
Direct Induction

ABSTRACT A color test has been developed for the selection and identification of mutants in Neurospora crassa, constitutive for the three normally inducible enzymes which convert quinate to protocatechuate. By this means seven such mutants have been recovered after ultra violet irradiation of wild type and have been shown to be allelic (or very closely linked) to the qa-1C mutants previously obtained by other means. Thus, the regulation of the synthesis of these three catabolic enzymes is indicated to be under the control of a single gene, qa-1+.

scholarly journals COMPLEMENTATION ANALYSIS OF LINKED CIRCADIAN CLOCK MUTANTS OF NEUROSPORA CRASSA

Genetics ◽  
1976 ◽  
Vol 82 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Jerry F Feldman ◽  
Marian N Hoyle
Keyword(s):  
Linkage Group ◽  
Circadian Clock ◽  
Neurospora Crassa ◽  
Period Length ◽  
Complementation Analysis ◽  
Wild Type ◽  
The Right

ABSTRACT A fourth mutant of Neurospora crassa, designated frq-4, has been isolated in which the period length of the circadian conidiation rhythm is shortened to 19.3 ± 0.3 hours. This mutant is tightly linked to the three previously isolated frq mutants, and all four map to the right arm of linkage group VII about 10 map units from the centromere. Complementation tests suggest, but do not prove, that all four mutations are allelic, since each of the four mutants is co-dominant with the frq  + allele—i.e., heterokaryons have period lengths intermediate between the mutant and wild-type—and since heterokaryons between pairs of mutants also have period lengths intermediate between those of the two mutants.

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