The Inhibitory Effect of HQNO Compared With Extrareduction and Binding in the Wild Type and in an Antimycin-resistant Mutant, ANTR 8, in Schizosaccharomyces pombe

1976 ◽  
pp. 399-408
Author(s):  
G. Burger ◽  
B. Lang ◽  
K. Wolf ◽  
W. Bandlow ◽  
F. Kaudewitz ◽  
...  
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Resistant Mutant ◽  
Inhibitory Effect ◽  
Wild Type ◽  
In The Wild

scholarly journals Effects of different drought treatments on root and shoot development of the tomato wild type and flacca mutant

2011 ◽  
Vol 63 (4) ◽  
pp. 1167-1171 ◽  
Author(s):  
Ljiljana Prokic ◽  
Radmila Stikic
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Inhibitory Effect ◽  
Root Density ◽  
Full Irrigation ◽  
Wild Type ◽  
Drought Treatment ◽  
In The Wild ◽  
Partial Root Drying

The effects of drought and partial root drying (PRD) on shoot and root growth was assessed in the wild type Ailsa Craig (WT) and the flacca tomato mutant deficient in the plant hormone ABA. Our results show that drought had an inhibitory effect on shoot growth in flacca and especially in WT; the most profound effect was observed in FI (full irrigation), then PRD and the smallest in D plants. Root development in both WT and flacca was stimulated after the 3rd day of the experiment following a decrease in the soil water content. On the 11th day of the experiment, when the soil water content was reduced by about 50% of full irrigation (FI), the root density was increased in the drying part of the PDR and on both sides of the drought treatment. On the basis of these results it can be assumed that increased root density and root length represent an adaptation or root adjustment to drought conditions.

Cloning of the ATP sulphurylase gene of Schizosaccharomyces pombe by functional complementation

2008 ◽  
Vol 54 (1) ◽  
pp. 71-74 ◽  
Author(s):  
Tibor Simonics ◽  
Anna Maráz
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Genomic Library ◽  
Resistant Mutant ◽  
Selection Marker ◽  
Wild Type ◽  
Comparable Amount ◽  
Reading Frame ◽  
Negative Selection Marker ◽  
Efficient Selection ◽  
Atp Sulphurylase

The ATP sulphurylase gene of Schizosaccharomyces pombe has been cloned by complementation of cysteine auxotrophy of a selenate-resistant mutant, which supposedly had a defect in ATP sulphurylase. A sulphate nonutilizing (cysteine auxotrophic) and selenate-resistant mutant of S. pombe was transformed with a wild-type S. pombe genomic library and sulphate-utilizing clones were isolated. The open reading frame encoding the ATP sulphurylase enzyme was found to be responsible for the restoration of sulphate assimilation. Transformants became as sensitive for selenate as the wild-type strain and produced a comparable amount of ATP sulphurylase as the prototrophic strains. The cloned ATP sulphurylase gene (sua1) proved to be an efficient selection marker in an ARS vector, when different isogenic or nonisogenic S. pombe selenate-resistant mutants were used as cloning hosts. Complementation of sua1– mutations by sua1-bearing multicopy vectors functions as a useful dual positive and negative selection marker. The cloned sua1 gene also complemented the met3 (ATP sulphurylase deficient) mutation in Saccharomyces cerevisiae .

scholarly journals Effects of Chloramphenicol on the Mitochondrial Respiratory Chain in the Wild Strain and in a Cytoplasmic Chloramphenicol-Resistant Mutant ofTetrahymena pyriformis

1982 ◽  
Vol 2 (6) ◽  
pp. 715-719 ◽  
Author(s):  
Roland Perasso ◽  
Jean-Jacques Curgy ◽  
Nicole Stelly ◽  
Jean Andre
Keyword(s):  
Oxygen Consumption ◽  
Cytochrome Oxidase ◽  
Oxidase Activity ◽  
Wild Strain ◽  
Resistant Mutant ◽  
Wild Type ◽  
Mitochondrial Translation ◽  
Cytochrome Oxidase Activity ◽  
In The Wild ◽  
Mitochondrial Respiratory

The effects of chloramphenicol (CAP) on mitochondrial respiratory activity in the wild strain (ST) and in a cytoplasmic CAP-resistant mutant (STR1) ofTetrahymena pyriformiswere studied by determining oxygen consumption, by spectrophotometry, and by cytochemistry. In the absence of CAP both strains had the same respiration capacity, and the low-temperature spectra of their isolated mitochondria were similar. Furthermore, the mitochondria of both strains showed a positive reaction with diaminobenzidine, denoting a similar cytochrome oxidase activity. However, when cells were grown in CAP for 24 or 48 h, the peaks of cytochrome oxidase and cytochromebwere almost absent in the wild type. In this type the oxygen consumption was greatly decreased, and the mitochondria were no longer stained by diaminobenzidine. In the mutant, the peaks of cytochrome oxidase and cytochromebwere decreased only; respiration was less affected than in the wild type, and cytochrome oxidase activity was still disclosed by the diaminobenzidine reaction. These results show that CAP inhibits the synthesis of two cytochromes (band oxidase) which are partially translated into the mitochrondria ofT. pyriformis.In the mutant, CAP reduces only the mitochondrial translation, resulting in reduced mitochondrial activity and reduced growth rate of the cell. These results are compared with the nucleo-mitochondrial regulation mechanisms discussed in our previous works.

The role of catalase in hydrogen peroxide resistance in fission yeast Schizosaccharomyces pombe

1999 ◽  
Vol 45 (2) ◽  
pp. 125-129 ◽  
Author(s):  
Norihiro Mutoh ◽  
Chiaki W Nakagawa ◽  
Kenichiro Yamada
Keyword(s):  
Hydrogen Peroxide ◽  
Schizosaccharomyces Pombe ◽  
Catalase Activity ◽  
Parent Strain ◽  
Normal Growth ◽  
Wild Type ◽  
Catalase Gene ◽  
In The Wild ◽  
High Concentrations

The role of catalase in hydrogen peroxide resistance in Schizosaccharomyces pombe was investigated. A catalase gene disruptant completely lacking catalase activity is more sensitive to hydrogen peroxide than the parent strain. The mutant does not acquire hydrogen peroxide resistance by osmotic stress, a treatment that induces catalase activity in the wild-type cells. The growth rate of the disruptant is not different from that of the parent strain. Additionally, transformed cells that overexpress the catalase activity are more resistant to hydrogen peroxide than wild-type cells with normal catalase activity. These results indicate that the catalase of S. pombe plays an important role in resistance to high concentrations of hydrogen peroxide but offers little in the way of protection from the hydrogen peroxide generated in small amounts under normal growth conditions.Key words: catalase, gene disruption, induced hydrogen peroxide resistance, overexpression, Schizosaccharomyces pombe.

scholarly journals ISOLATION AND PROPERTIES OF SELENOMETHIONINE-RESISTANT MUTANTS OF NEUROSPORA CRASSA

Genetics ◽  
1974 ◽  
Vol 77 (4) ◽  
pp. 627-638
Author(s):  
Gregory S Chen ◽  
Robert L Metzenberg
Keyword(s):  
Resistant Mutant ◽  
Heat Stability ◽  
Temperature Sensitive ◽  
Wild Type ◽  
High Concentration ◽  
Type Locus ◽  
Group I ◽  
In The Wild ◽  
Resistant Mutants ◽  
Adenosylmethionine Synthetase

ABSTRACT Mutants resistant to selenomethionine were isolated, and their properties studied. Mapping studies indicate that the mutation sites are located near the eth-1r locus in linkage group I, about ten map units away from the mating type locus. The sites of new mutation are either allelic to or very close to eth-1r. They are resistant not only to selenomethionine but also to ethionine, while the ethionine-resistant mutant, eth-1r, is sensitive to selenomethionine. The selenomethionine-resistant mutants are also temperature-sensitive mutants. However, they can grow at higher temperatures in medium containing 1 M glycerol.—It is very unlikely that the resistance is due to a change in the permeability of the membrane. Aryl sulfatase of se-metr mutants is not repressed by a high concentration of methionine (5 mM), although inorganic sulfate (2 mM) still can cause total repression. The γ-cystathionase levels of the mutants are normal, but the S-adenosylmethionine synthetase levels are only one-tenth of that observed in the wild-type strain. The heat-stability of this enzyme in the mutant is also different from that of the wild-type enzyme suggesting that the mutation might affect the structural gene of S-adenosylmethionine synthetase.

scholarly journals A temperature-sensitive mutation of the Schizosaccharomyces pombe gene nuc2+ that encodes a nuclear scaffold-like protein blocks spindle elongation in mitotic anaphase.

1988 ◽  
Vol 106 (4) ◽  
pp. 1171-1183 ◽  
Author(s):  
T Hirano ◽  
Y Hiraoka ◽  
M Yanagida
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Gradient Centrifugation ◽  
Metaphase Plate ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Wild Type ◽  
In The Wild ◽  
Spindle Elongation ◽  
Mutant Cells

A temperature-sensitive mutant nuc2-663 of the fission yeast Schizosaccharomyces pombe specifically blocks mitotic spindle elongation at restrictive temperature so that nuclei in arrested cells contain a short uniform spindle (approximately 3-micron long), which runs through a metaphase plate-like structure consisting of three condensed chromosomes. In the wild-type or in the mutant cells at permissive temperature, the spindle is fully extended approximately 15-micron long in anaphase. The nuc2' gene was cloned in a 2.4-kb genomic DNA fragment by transformation, and its complete nucleotide sequence was determined. Its coding region predicts a 665-residues internally repeating protein (76.250 mol wt). By immunoblots using anti-sera raised against lacZ-nuc2+ fused proteins, a polypeptide (designated p67; 67,000 mol wt) encoded by nuc2+ is detected in the wild-type S. pombe extracts; the amount of p67 is greatly increased when multi-copy or high-expression plasmids carrying the nuc2+ gene are introduced into the S. pombe cells. Cellular fractionation and Percoll gradient centrifugation combined with immunoblotting show that p67 cofractionates with nuclei and is enriched in resistant structure that is insoluble in 2 M NaCl, 25 mM lithium 3,5'-diiodosalicylate, and 1% Triton but is soluble in 8 M urea. In nuc2 mutant cells, however, soluble p76, perhaps an unprocessed precursor, accumulates in addition to insoluble p67. The role of nuc2+ gene may be to interconnect nuclear and cytoskeletal functions in chromosome separation.

scholarly journals Dual Role of Cysteine 172 in Redox Regulation of Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase Activity and Degradation

2003 ◽  
Vol 185 (5) ◽  
pp. 1509-1517 ◽  
Author(s):  
Yehouda Marcus ◽  
Hagit Altman-Gueta ◽  
Aliza Finkler ◽  
Michael Gurevitz
Keyword(s):  
Redox Regulation ◽  
Inhibitory Effect ◽  
Cysteine Residues ◽  
Wild Type ◽  
Bisphosphate Carboxylase ◽  
Enzyme Form ◽  
Oxygenase Activity ◽  
In The Wild ◽  
Cross Links

ABSTRACT Alkylation and oxidation of cysteine residues significantly decrease the catalytic activity and stimulate the degradation of ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO). We analyzed the role of vicinal cysteine residues in redox regulation of RuBisCO from Synechocystis sp. strain PCC 6803. Cys172 and Cys192, which are adjacent to the catalytic site, and Cys247, which cross-links two large subunits, were replaced by alanine. Whereas all mutant cells (C172A, C192A, C172A-C192A, and C247A) and the wild type grew photoautotrophically at similar rates, the maximal photosynthesis rates of C172A mutants decreased 10 to 20% as a result of 40 to 60% declines in RuBisCO turnover number. Replacement of Cys172, but not replacement of Cys192, prominently decreased the effect of cysteine alkylation or oxidation on RuBisCO. Oxidants that react with vicinal thiols had a less inhibitory effect on the activity of either the C172A or C192A enzyme variants, suggesting that a disulfide bond was formed upon oxidation. Thiol oxidation induced RuBisCO dissociation into subunits. This effect was either reduced in the C172A and C192A mutant enzymes or eliminated by carboxypentitol bisphosphate (CPBP) binding to the activated enzyme form. The CPBP effect presumably resulted from a conformational change in the carbamylated CPBP-bound enzyme, as implied from an alteration in the electrophoretic mobility. Stress conditions, provoked by nitrate deprivation, decreased the RuBisCO contents and activities in the wild type and in the C192A and C247A mutants but not in the C172A and C172A-C192A mutants. These results suggest that although Cys172 does not participate in catalysis, it plays a role in redox regulation of RuBisCO activity and degradation.

scholarly journals Activation and regulation of the Spc1 stress-activated protein kinase in Schizosaccharomyces pombe.

1996 ◽  
Vol 16 (6) ◽  
pp. 2870-2877 ◽  
Author(s):  
G Degols ◽  
K Shiozaki ◽  
P Russell
Keyword(s):  
Protein Kinase ◽  
Osmotic Stress ◽  
Schizosaccharomyces Pombe ◽  
Tyrosine Phosphatase ◽  
Negative Regulator ◽  
Mitogen Activated Protein Kinase ◽  
Wild Type ◽  
Expression Of Genes ◽  
In The Wild

Spc1, an osmotic-stress-stimulated mitogen-activated protein kinase (MAPK) homolog in the fission yeast Schizosaccharomyces pombe, is required for the induction of mitosis and survival in high-osmolarity conditions. Spc1, also known as Sty1, is activated by Wis1 MAPK kinase and inhibited by Pyp1 tyrosine phosphatase. Spc1 is most closely related to Saccharomyces cerevisiae Hog1 and mammalian p38 kinases. Whereas Hog1 is specifically responsive to osmotic stress, we report here that Spc1 is activated by multiple forms of stress, including high temperature and oxidative stress. In this regard Spc1 is more similar to mammalian p38. Activation of Spc1 is crucial for survival of various forms of stress. Spc1 regulates expression of genes encoding stress-related proteins such as glycerol-3-phosphate dehydrogenase (gpd1+) and trehalose-6-phosphate synthase (tps1+). Spc1 also promotes expression of pyp2+, which encodes a tyrosine phosphatase postulated as a negative regulator of Spc1. This proposal is supported by the finding that Spc1 associates with Pyp2 in vivo and that the amount of Spc1 tyrosine phosphorylation is lower in a Pyp2-overproducing strain than in the wild type. Moreover, the level of stress-stimulated gpd1+ expression is higher in delta pyp2 mutants than in the wild type. These findings demonstrate that Spc1 promotes expression of genes involved in stress survival and that of regulation may be commonly employed to modulate MAPK signal transduction pathways in eukaryotic species.

scholarly journals Controlling the hypermutation: Exploitation of the MutS protein in Pseudomonas aeruginosa

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Yue Yuan On ◽  
Martin Welch
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Type Strain ◽  
Wild Type Strain ◽  
Resistant Mutant ◽  
Inducible Promoter ◽  
Wild Type ◽  
Cdna Analysis ◽  
In The Wild ◽  
Mismatch Recognition ◽  
Muts Gene

Pseudomonas aeruginosa infections commonly develop in individuals with cystic fibrosis (CF), and its adaptation in such an unfavourable condition is always found to be related to hypermutation. In fact, most of the hypermutation is due to the defects in mutS gene which involves in the mismatch repair mechanism, causing the acceleration of mutation rate and adaptive evolution. In order to rheostatically express the MutS protein and achieve “hypomutation” (in which the rate of mutation is lower than that of wild type strain), an exogenous mutS gene with rhamnose-inducible promoter was cloned into MPAO1 mutS::Tn mutant strain. Present findings demonstrate that this system is tightly-controlled and stable, with less rifampicin-resistant mutant frequency and more fluorescence intensity from a GFP-tagged MutS expressing cells were observed when the concentration of the inducer increases. Interestingly, the results from Western blot analysis show that less MutS protein is required to suppress hypermutation in the wild type strain, as compared to our construct that behaves similar to the wild type but obviously needs more MutS expression to achieve such state. This indicates that the exogenous MutS might be lacking of other important protein to work efficiently in mismatch recognition. Therefore, based on our cDNA analysis, we found that fdxA gene next to the mutS gene is in the same operon, which could suggest that they might be functionally related in the DNA repair machinery.

Characterization of a norflurazon-resistant mutant of Chlamydomonas reinhardtii

Weed Science ◽  
1997 ◽  
Vol 45 (3) ◽  
pp. 374-377 ◽  
Author(s):  
Varsha Vartak ◽  
Sujata Bhargava
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Mode Of Action ◽  
Resistant Mutant ◽  
Phytoene Desaturase ◽  
Wild Type ◽  
Cross Tolerance ◽  
In The Wild ◽  
Similar Mode ◽  
Target Enzyme

A norflurazon-resistant mutant has been isolated from Chlamydomonas reinhardtii that showed a three-fold factor of resistance over wild type cultures. In comparison to wild type cultures, the mutant showed better retention of chlorophylls and carotenoids when grown in light in the presence of norflurazon. When grown in the dark, chlorophyll losses were similar, while carotenoid losses were lower than in the wild type cultures. Higher levels of phytoene accumulated in the wild type cultures in the presence of norflurazon than in the resistant cultures. The resistant cultures also showed cross tolerance to EMD-IT 5914, a herbicide with a similar mode of action. Norflurazon resistance in this alga appears to arise from alterations in the target enzyme phytoene desaturase.

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