Extrachromosomal oligomycin-resistant mutants of the petite-negative yeast Kluyveromyces lactis. Properties of mitochondrial ATPase and cross-resistance to inhibitors of phosphoryl transfer reactions

1980 ◽  
Vol 178 (2) ◽  
pp. 351-355 ◽  
Author(s):  
Aurora Brunner L. ◽  
Alba Tuena de Cobos
Keyword(s):  
Kluyveromyces Lactis ◽  
Transfer Reactions ◽  
Cross Resistance ◽  
Phosphoryl Transfer ◽  
Mitochondrial Atpase ◽  
Resistant Mutants ◽  
Petite Negative Yeast

scholarly journals Nuclear and cytoplasmic cross-resistance and correlated sensitivity to DNA intercalating drugs in a petite-negative yeast

1975 ◽  
Vol 25 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Esteban Celis ◽  
Jaime Mas ◽  
Aurora Brunner
Keyword(s):  
Drug Resistance ◽  
Ethidium Bromide ◽  
Kluyveromyces Lactis ◽  
Natural Resistance ◽  
Cross Resistance ◽  
Wild Type ◽  
Nuclear Mutation ◽  
Nuclear Mutations ◽  
Resistant Mutants ◽  
Petite Negative Yeast

SUMMARYEthidium bromide and acriflavin-resistant mutants of petite-negative yeast Kluyveromyces lactis were prepared. One kind of nuclear mutation (EBR1) gave resistance to ethidium bromide and correlated sensitivity towards acriflavin. Another nuclear mutation (EBR2) did not affect ‘natural’ resistance of this yeast towards 15 μM acriflavin. Both nuclear mutations mapped at different loci, suggesting lack of linkage. Cytoplasmic mutants resistant to these two drugs were unstable when grown in complete media with dextrose, reverting to a wild-type resistance genotype. When grown in glycerol-containing media these mutants maintained their cytoplasmic drug-resistance conferring factors.

scholarly journals Expression of the Saccharomyces cerevisiae Gene YME1 in the Petite-Negative Yeast Schizosaccharomyces pombe Converts It to Petite-Positive

Genetics ◽  
2000 ◽  
Vol 154 (1) ◽  
pp. 147-154 ◽  
Author(s):  
Douglas J Kominsky ◽  
Peter E Thorsness
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitochondrial Dna ◽  
Schizosaccharomyces Pombe ◽  
Atp Synthase ◽  
Kluyveromyces Lactis ◽  
Blot Hybridization ◽  
Inner Mitochondrial Membrane ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mitochondrial Atp Synthase ◽  
Petite Negative Yeast

Abstract Organisms that can grow without mitochondrial DNA are referred to as “petite-positive” and those that are inviable in the absence of mitochondrial DNA are termed “petite-negative.” The petite-positive yeast Saccharomyces cerevisiae can be converted to a petite-negative yeast by inactivation of Yme1p, an ATP- and metal-dependent protease associated with the inner mitochondrial membrane. Suppression of this yme1 phenotype can occur by virtue of dominant mutations in the α- and γ-subunits of mitochondrial ATP synthase. These mutations are similar or identical to those occurring in the same subunits of the same enzyme that converts the petite-negative yeast Kluyveromyces lactis to petite-positive. Expression of YME1 in the petite-negative yeast Schizosaccharomyces pombe converts this yeast to petite-positive. No sequence closely related to YME1 was found by DNA-blot hybridization to S. pombe or K. lactis genomic DNA, and no antigenically related proteins were found in mitochondrial extracts of S. pombe probed with antisera directed against Yme1p. Mutations that block the formation of the F1 component of mitochondrial ATP synthase are also petite-negative. Thus, the F1 complex has an essential activity in cells lacking mitochondrial DNA and Yme1p can mediate that activity, even in heterologous systems.

scholarly journals Point Mutations in the β-Tubulin of Phytophthora sojae Confer Resistance to Ethaboxam

2019 ◽  
Vol 109 (12) ◽  
pp. 2096-2106 ◽  
Author(s):  
Qin Peng ◽  
Zhiwen Wang ◽  
Yuan Fang ◽  
Weizhen Wang ◽  
Xingkai Cheng ◽  
...  
Keyword(s):  
Fungicide Resistance ◽  
Germination Rate ◽  
Management Strategies ◽  
Resistance Management ◽  
Point Mutations ◽  
Phytophthora Sojae ◽  
Cross Resistance ◽  
Baseline Sensitivity ◽  
Resistant Mutants ◽  
Β Tubulin

Ethaboxam is a β-tubulin inhibitor registered for the control of oomycete pathogens. The current study was established to determine the ethaboxam sensitivity of the plant pathogen Phytophthora sojae and investigate the potential for the emergence of fungicide resistance. The effective concentration for 50% inhibition (EC50) of 112 Phytophthora sojae isolates exhibited a unimodal distribution with a mean EC50 for ethaboxam of 0.033 µg/ml. Establishing this baseline sensitivity provided critical data for monitoring changes in ethaboxam-sensitivity in field populations. The potential for fungicide resistance was investigated using adaptation on ethaboxam-amended V8 agar, which resulted in the isolation of 20 resistant mutants. An assessment of the biological characteristics of the mutants including mycelial growth, sporulation, germination rate and pathogenicity indicated that the resistance risk in Phytophthora sojae was low to medium with no cross-resistance between ethaboxam and cymoxanil, metalaxyl, flumorph, and oxathiapiprolin being detected. However, positive cross-resistance was found between ethaboxam and zoxamide for Q8L and I258V but negative cross-resistance for C165Y. Further investigation revealed that the ethaboxam-resistant mutants had point mutations at amino acids Q8L, C165Y, or I258V of their β-tubulin protein sequences. CRISPR/Cas9-mediated transformation experiments confirmed that the Q8L, C165Y, or I258V mutations could confer ethaboxam resistance in Phytophthora sojae and that the C165Y mutation induces high levels of resistance. Taken together, the results of the study provide essential data for monitoring the emergence of resistance and resistance management strategies for ethaboxam, as well as for improving the design of novel β-tubulin inhibitors for future development.

An Alternative Role for the Conserved Asp Residue in Phosphoryl Transfer Reactions

1998 ◽  
Vol 120 (51) ◽  
pp. 13535-13536 ◽  
Author(s):  
Jason C. Hart ◽  
Ian H. Hillier ◽  
Neil A. Burton ◽  
David W. Sheppard
Keyword(s):  
Transfer Reactions ◽  
Phosphoryl Transfer
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