The effects of chloramphenicol on S. cerevisiae and a cytoplasmic respiratory-deficient mutant derived from the same strain are compared. In normal yeast, high concentrations in growth medium completely inhibit formation cytochromes a, a(3), b, c(1) partially succinate dehydrogenase formation, whereas they do not affect cytochrome c synthesis. This has been correlated with marked reduction mitochondrial cristae presence drug. glucose-repressed little effect outer membrane, or synthesis...

Saccharomyces cerevisiae contains 62 molecules per cell of a class covalently closed circular DNA termed omicron ( o DNA) buoyant density 1.701 g/cm 3 with major size 1.9 μm. The localization has been investigated in respiratory deficient mutant 2eρ −1 containing altered mitochondrial (ρDNA) the form circles. There are 81 ρDNA and they range from 0.05 μm to 1.6 have 1.676 . When this mini‐circular is used as marker cytoplasmic contamination, we find that purified nuclei do not contain DNA....

Breakage and fractionation of respiratory competent yeast in the presence ethidium bromide, subsequent centrifugation a detergent lysate mitochondrial fraction by dye-buoyant-density technique, results isolation closed-circular DNA. After removal bound dye, this DNA has two components when analyzed equilibrium buoyant density analytical ultracentrifuge. A minor component 1.684 g/cm(3), which is characteristic DNA, but major 1.701 g/cm(3). This species also present that have been mutagenized...

Spirillum itersonii contains b - and c -type cytochromes as well a carbon monoxide-binding pigment of the cytochrome o type. Synthesis is increased by about two- fourfold, respectively, when cells are transferred from high to low aeration. The concentration not accompanied an increase in respiration rate cells. Both located particulate fraction grown under or aeration, both pigments fully reducible succinate. No evidence was found for accumulation protein component either synthesis...

Abstract By employing pulsed‐field gel electrophoresis we have determined the size of rDNA cluster in wild‐type yeast strains representing genera Candida , Kluyveromyces Pachysolen Schizosaccharomyces and Torulaspora . Although genome examined species is similar (12·3–13·9 Mb), at least a four‐fold variation has been observed between lowest amount repeats P. tannophilus (28) highest C. glabrata S. poombe (> 115). In two represented by loci, residing either one ( pombe ) or chromosomes ).

Fatty acid and sterol content composition were determined for the dimorphic mold, Mucor genevensis , grown under a variety of experimental conditions. acids account 6 to 9% dry weight aerobically mycelium, 70 80% these are unsaturated. The organism contains γ-linolenic which is characteristic Phycomycetes in sporangiospores this compound represents 40% total fatty acids. Of sterols found ergosterol, stigmasterol was positively identified as one minor components. In anaerobically yeastlike...

Abstract Following targeted disruption of the unique CYC1 gene, petite-negative yeast, Kluyveromyces lactis, was found to grow fermentatively in absence cytochrome c-mediated respiration. This observation encouraged us seek mitochondrial mutants by treatment K. lactis with ethidium bromide at highest concentration permitting survival. By this technique, we isolated four mtDNA mutants, three lacking and one a deleted genome. In isolates mtDNA, nuclear mutation is present that permits petite...

Purified mitochondria from the petite positive yeast Torulopsis glabrata contain a circular deoxyribonucleic acid (DNA) with length of 6 mum and buoyant density 1.686 g/cm3. This DNA is absent ethidium bromide induced respiratory-deficient mutants.

Closed-circular DNA has been isolated from mitochondrial-enriched fractions four petite-negative' yeasts. Electron microscope analysis shown in each case the presence of a large discrete size class circular greater than 6 μm length and smaller heterodisperse less μm. Length molecular weight measurements are: Candida parapsilosis, 11.14 ± 0.45 μ 23.1 × 106; Hansenula wingei, 8.22 0.43 17.3 Kluyveromyces lactis, 11.44 0.20 24.0 106 Schizosaccharomyces pombe, 6.04 0.16 12.5 106. These DNAs are...

SUMMARY We propose a general hypothesis involving properties of circular DNA which can explain such phenomena as the petite mutation, suppressiveness, and polarity observed in mitochondrial recombination yeast Saccharomyces cerevisiae . This involves excision insertion events between molecules well structural rearrangements generated by these events. The special have been considered analysing recombination, number results are obtained not intuitively apparent. be applied to any situation...