scholarly journals Mutants With Altered Sensitivity to a Calmodulin Antagonist Affect the Circadian Clock in Neurospora crassa

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1175-1180 ◽  
Author(s):  
Sakura Suzuki ◽  
Satoshi Katagiri ◽  
Hideaki Nakashima
Keyword(s):  
Neurospora Crassa ◽  
Period Length ◽  
Phase Shifting ◽  
Wild Type ◽  
Inhibitory Effects ◽  
Calmodulin Antagonist ◽  
Mutant Strains ◽  
In The Wild ◽  
Altered Sensitivity ◽  
Clock Mechanism

Abstract Two newly isolated mutant strains of Neurospora crassa, cpz-1 and cpz-2, were hypersensitive to chlorpromazine with respect to mycelial growth but responded differently to the drug with respect to the circadian conidiation rhythm. In the wild type, chlorpromazine caused shortening of the period length of the conidiation rhythm. Pulse treatment with the drug shifted the phase and inhibited light-induced phase shifting in Neurospora. By contrast to the wild type, the cpz-2 strain was resistant to these inhibitory effects of chlorpromazine. Inhibition of cpz-2 function by chlorpromazine affected three different parameters of circadian conidiation rhythm, namely, period length, phase and light-induced phase shifting. These results indicate that the cpz-2 gene must be involved in or related closely to the clock mechanism of Neurospora. By contrast, the cpz-1 strain was hypersensitive to chlorpromazine with respect to the circadian conidiation rhythm.

scholarly journals Mutation of the cys-9 Gene, Which Encodes Thioredoxin Reductase, Affects the Circadian Conidiation Rhythm in Neurospora crassa

Genetics ◽  
1997 ◽  
Vol 146 (1) ◽  
pp. 101-110 ◽  
Author(s):  
Kiyoshi Onai ◽  
Hideaki Nakashima
Keyword(s):  
Neurospora Crassa ◽  
Type Strain ◽  
Temperature Compensation ◽  
Wild Type Strain ◽  
Thioredoxin Reductase ◽  
Period Length ◽  
Phase Shifting ◽  
Wild Type ◽  
Partial Loss ◽  
Continuous Darkness

Ten cysteine auxotrophs of Neurospora crassa were examined with regard to the period lengths of their circadian conidiation rhythms. One of the these cysteine auxotrophs, cys-9, showed dramatic changes in the circadian conidiation rhythm. At 10 μm methionine, the cys-9 mutant had a period length that was 5 hr shorter than that of the wild-type strain during the first 3 days after transfer to continuous darkness. At this concentration of methionine, the period length was unstable after the fourth day and varied widely from 11 to 31 hr. In contrast, other cysteine auxotrophs did not show such instability of the period length at any of the concentrations of methionine tested. Furthermore, only the cys-9 mutant exhibited partial loss of the capacity for temperature compensation of the period length. With regard to cold-induced phase-shifting of the circadian conidiation rhythm, the cys-9 mutant was more sensitive than the wild-type strain to low temperature. The cys-9  + gene was cloned and was found to encode NADPH-dependent thioredoxin reductase. These results indicate that mutation of the gene for thioredoxin reductase results in abnormal expression of the circadian conidiation rhythm in N. crassa.

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.

scholarly journals Blocks in the pseudouridimycin pathway unlock hidden metabolites in the Streptomyces producer strain

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marianna Iorio ◽  
Sahar Davatgarbenam ◽  
Stefania Serina ◽  
Paolo Criscenzo ◽  
Mitja M. Zdouc ◽  
...  
Keyword(s):  
Gene Clusters ◽  
Biosynthetic Gene Cluster ◽  
Systematic Investigation ◽  
Biosynthetic Gene ◽  
Wild Type ◽  
Bacterial Rna ◽  
Soil Isolate ◽  
Mutant Strains ◽  
In The Wild ◽  
Polymerase Inhibitor

AbstractWe report a metabolomic analysis of Streptomyces sp. ID38640, a soil isolate that produces the bacterial RNA polymerase inhibitor pseudouridimycin. The analysis was performed on the wild type, on three newly constructed and seven previously reported mutant strains disabled in different genes required for pseudouridimycin biosynthesis. The results indicate that Streptomyces sp. ID38640 is able to produce, in addition to lydicamycins and deferroxiamines, as previously reported, also the lassopeptide ulleungdin, the non-ribosomal peptide antipain and the osmoprotectant ectoine. The corresponding biosynthetic gene clusters were readily identified in the strain genome. We also detected the known compound pyridindolol, for which we propose a previously unreported biosynthetic gene cluster, as well as three families of unknown metabolites. Remarkably, the levels of most metabolites varied strongly in the different mutant strains, an observation that enabled detection of metabolites unnoticed in the wild type. Systematic investigation of the accumulated metabolites in the ten different pum mutants identified shed further light on pseudouridimycin biosynthesis. We also show that several Streptomyces strains, able to produce pseudouridimycin, have distinct genetic relationship and metabolic profile with ID38640.

Sensitivity of normal and mutant strains of Escherichia coli to actinomycin-D

1972 ◽  
Vol 18 (6) ◽  
pp. 909-915 ◽  
Author(s):  
A. P. Singh ◽  
K.-J. Cheng ◽  
J. W. Costerton ◽  
E. S. Idziak ◽  
J. M. Ingram
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Wild Type Strain ◽  
Actinomycin D ◽  
Cytoplasmic Membrane ◽  
Cell Envelope ◽  
Coli Strain ◽  
Wild Type ◽  
Mutant Strains ◽  
In The Wild

The site of the cell barrier to actinomycin-D uptake was studied using a wild-type Escherichia coli strain P and its cell envelope-defective filamentous mutants, strains 6γ and 12γ, both of which 'leak' β-galactosidase and alkaline phosphatase into the medium during growth indicating both membrane and cell-wall defects. Actinomycin-D entered the cells of these two mutant strains as evidenced by the inhibition of both 14C-uracil incorporation and synthesis of the induced β-galactosidase system. Under similar conditions, no inhibition occurred in the wild-type strain and its sucrose-lysozyme prepared spheroplasts. Actinomycin-D did, however, inhibit the above-mentioned systems in the wild-type sucrose-lysozyme spheroplasts prepared in the presence of 2 mM EDTA. The experimental data indicate that although the cell wall may act as a primary barrier or sieve to actinomycin-D, the cytoplasmic membrane should be considered the final and determinative barrier to this antibiotic.

scholarly journals Adenosine kinase-deficient mutant of Neurospora crassa

1982 ◽  
Vol 152 (3) ◽  
pp. 1292-1294
Author(s):  
J M Magill ◽  
P Dalke ◽  
T S Lyda ◽  
C W Magill
Keyword(s):  
Neurospora Crassa ◽  
Resistant Mutant ◽  
Adenosine Kinase ◽  
Deficient Mutant ◽  
Wild Type ◽  
Purine Nucleotides ◽  
Mutant Strains

Tubercidin-resistant mutant strains of Neurospora crassa were isolated, and at least one appeared to be deficient in adenosine kinase. No significant differences in [8-14C]adenosine labeling of purine nucleotides or nucleosides were found between the wild type and the adenosine kinase-deficient strains.

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 One-carbon metabolism in Neurospora crassa wild-type and in mutants partially deficient in serine hydroxymethyltransferase

1976 ◽  
Vol 160 (2) ◽  
pp. 305-314 ◽  
Author(s):  
E A Cossins ◽  
P Y Chan ◽  
G Combepine
Keyword(s):  
Neurospora Crassa ◽  
Mutant Strain ◽  
Methylenetetrahydrofolate Reductase ◽  
Serine Hydroxymethyltransferase ◽  
Growth Media ◽  
Wild Type ◽  
Feeding Experiments ◽  
Methylenetetrahydrofolate Dehydrogenase ◽  
In The Wild ◽  
One Carbon Metabolism

1. The concentrations of folate-dependent enzymes in Neurospora crassa Lindegren A wild type (FGSC no. 853), Ser-l mutant, strain H605a (FGSC no. 118), and for mutant, strain C-24 (FGSC no. 9), were compared during exponential growth on defined minimal media. Both mutants were partially lacking in serine hydroxymethyltransferase, but contained higher concentrations of 10-formyltetrahydrofolate synthetase than did the wild type. Mycelia of the mutants contained higher concentrations of these enzymes when growth media were supplemented with 1mM-glycine. In the wild-type, this glycine supplement also increased the specific activities of 5,10-methylenetetrahydrofolate dehydrogenase and 5,10-methylenetetrahydrofolate reductase. 5. During growth, total folate and polyglutamyl folate concentrations were greatest in the wild-type. Methylfolates were not detected in mutant Ser-l, and were only present in the for mutant after growth in glycine-supplemented media. Exogenous glycine increased folate concentration threefold in the wild type, mainly owing to increases in unsubstituted polyglutamyl derivatives. 3. Feeding experiments using 14C-labelled substrates showed that C1 units were generated from formate, glycine and serine in the wild type. Greater incorporation of 14C occurred when mycelia were cultured in glycine-supplemented media. Formate and serine were precursors of C1 units in the mutants, but the ability to cleave glycine was slight or lacking.

scholarly journals Ohr plays a central role in bacterial responses against fatty acid hydroperoxides and peroxynitrite

2016 ◽  
Vol 114 (2) ◽  
pp. E132-E141 ◽  
Author(s):  
Thiago G. P. Alegria ◽  
Diogo A. Meireles ◽  
José R. R. Cussiol ◽  
Martín Hugo ◽  
Madia Trujillo ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Wild Type Strain ◽  
Wild Type ◽  
Glutathione Peroxidases ◽  
Mutant Strains ◽  
In The Wild ◽  
Acid Hydroperoxide ◽  
Lipoamide Dehydrogenase ◽  
Fatty Acid Hydroperoxides ◽  
Competition Assays

Organic hydroperoxide resistance (Ohr) enzymes are unique Cys-based, lipoyl-dependent peroxidases. Here, we investigated the involvement of Ohr in bacterial responses toward distinct hydroperoxides. In silico results indicated that fatty acid (but not cholesterol) hydroperoxides docked well into the active site of Ohr fromXylella fastidiosaand were efficiently reduced by the recombinant enzyme as assessed by a lipoamide-lipoamide dehydrogenase–coupled assay. Indeed, the rate constants between Ohr and several fatty acid hydroperoxides were in the 107–108M−1⋅s−1range as determined by a competition assay developed here. Reduction of peroxynitrite by Ohr was also determined to be in the order of 107M−1⋅s−1at pH 7.4 through two independent competition assays. A similar trend was observed when studying the sensitivities of a ∆ohrmutant ofPseudomonas aeruginosatoward different hydroperoxides. Fatty acid hydroperoxides, which are readily solubilized by bacterial surfactants, killed the ∆ohrstrain most efficiently. In contrast, both wild-type and mutant strains deficient for peroxiredoxins and glutathione peroxidases were equally sensitive to fatty acid hydroperoxides. Ohr also appeared to play a central role in the peroxynitrite response, because the ∆ohrmutant was more sensitive than wild type to 3-morpholinosydnonimine hydrochloride (SIN-1 , a peroxynitrite generator). In the case of H2O2insult, cells treated with 3-amino-1,2,4-triazole (a catalase inhibitor) were the most sensitive. Furthermore, fatty acid hydroperoxide and SIN-1 both induced Ohr expression in the wild-type strain. In conclusion, Ohr plays a central role in modulating the levels of fatty acid hydroperoxides and peroxynitrite, both of which are involved in host–pathogen interactions.

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.

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