The detection of mitotic and meiotic chromosome gain in the yeast Saccharomyces cerevisiae: Effects of methyl benzimidazol-2-yl carbamate, methyl methanesulfonate, ethyl methanesulfonate, dimethyl sulfoxide, propionitrile and cyclophosphamide monohydrate

1990 ◽  
Vol 242 (3) ◽  
pp. 231-258 ◽  
Author(s):  
S.G. Whittaker ◽  
S.F. Moser ◽  
D.H. Maloney ◽  
W.W. Piegorsch ◽  
M.A. Resnick ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dimethyl Sulfoxide ◽  
Meiotic Chromosome ◽  
Ethyl Methanesulfonate ◽  
Methyl Methanesulfonate ◽  
Yeast Saccharomyces Cerevisiae ◽  
Chromosome Gain

PURE AND MOSAIC CLONES — A REFLECTION OF DIFFERENCES IN MECHANISMS OF MUTAGENESIS BY DIFFERENT AGENTS IN SACCHAROMYCES CEREVISIAE

1981 ◽  
Vol 23 (1) ◽  
pp. 73-79 ◽  
Author(s):  
A. Nasim ◽  
M. A. Hannan ◽  
Earle R. Nestmann
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ultraviolet Light ◽  
Nitrous Acid ◽  
Repair Process ◽  
Dna Lesions ◽  
Ethyl Methanesulfonate ◽  
Methyl Methanesulfonate ◽  
Mechanisms Of Mutagenesis ◽  
G1 Cells

The induction of pure and mosaic clones has been studied in haploid G1 cells of Saccharomyces cerevisiae. Following treatments with ultraviolet light, methyl methanesulfonate, ethyl methanesulfonate, nitrous acid, and N-methyl-N′-nitro-N-nitrosoguanidine, the relative proportions of pure mutant clones varied from 25 to 100% at comparable survival levels. Ultraviolet light and methyl methanesulfonate produced mainly pure mutant clones, whereas ethyl methanesulfonate and nitrous acid produced mainly mosaics at 59 to 100% survival levels. The ratio of pure to mosaic clones induced by nitrosoguanidine fell between these two classes. These results are consistent with a classification of mutagens on the basis of repair and replication-dependent mechanisms of mutagenesis in other organisms. Agents having actions similar to ultraviolet light may produce mainly pure clones through a pre-replicative process involving an error-prone DNA repair process. Others may produce mainly mosaic mutants due to the different nature of DNA lesions which may require a replication-dependent process for fixation of mutations. Preliminary data from combined treatments of mutagens belonging to two different classes (i.e. ultraviolet light and nitrous acid) suggest the possibility of an interaction between these agents, resulting in a higher proportion of pure clones, possibly due to an inducible process. Studies of induced frequencies of pure and mosaic clones may be useful in the characterization of mutagens with functional differences.

scholarly journals Three-dimensional Ultrastructure of Saccharomyces cerevisiae Meiotic Spindles

2005 ◽  
Vol 16 (3) ◽  
pp. 1178-1188 ◽  
Author(s):  
Mark Winey ◽  
Garry P. Morgan ◽  
Paul D. Straight ◽  
Thomas H. Giddings ◽  
David N. Mastronarde
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Chromosome ◽  
Three Dimensional ◽  
Structural Basis ◽  
Mitotic Spindles ◽  
Yeast Saccharomyces Cerevisiae ◽  
Homologous Chromosomes ◽  
Sister Chromatids ◽  
Single Nucleus ◽  
Meiotic Spindles

Meiotic chromosome segregation leads to the production of haploid germ cells. During meiosis I (MI), the paired homologous chromosomes are separated. Meiosis II (MII) segregation leads to the separation of paired sister chromatids. In the budding yeast Saccharomyces cerevisiae, both of these divisions take place in a single nucleus, giving rise to the four-spored ascus. We have modeled the microtubules in 20 MI and 15 MII spindles by using reconstruction from electron micrographs of serially sectioned meiotic cells. Meiotic spindles contain more microtubules than their mitotic counterparts, with the highest number in MI spindles. It is possible to differentiate between MI versus MII spindles based on microtubule numbers and organization. Similar to mitotic spindles, kinetochores in either MI or MII are attached by a single microtubule. The models indicate that the kinetochores of paired homologous chromosomes in MI or sister chromatids in MII are separated at metaphase, similar to mitotic cells. Examination of both MI and MII spindles reveals that anaphase A likely occurs in addition to anaphase B and that these movements are concurrent. This analysis offers a structural basis for considering meiotic segregation in yeast and for the analysis of mutants defective in this process.

A Saccharomyces cerevisiae mutant defines a new locus essential for resistance to the antitumour drug bleomycin

1996 ◽  
Vol 42 (8) ◽  
pp. 835-843 ◽  
Author(s):  
Dindial Ramotar ◽  
Jean-Yves Masson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Hydrogen Peroxide ◽  
Dna Repair ◽  
Chromosomal Translocation ◽  
Normal Growth ◽  
Fold Increase ◽  
Growth Conditions ◽  
Dna Lesions ◽  
Methyl Methanesulfonate ◽  
Yeast Saccharomyces Cerevisiae

The antitumor drug bleomycin can produce a variety of lesions in the cellular DNA by a free radical dependent mechanism. To understand how these DNA lesions are repaired, bleomycin-hypersensitive mutants were isolated from the yeast Saccharomyces cerevisiae. We report here the analysis of one mutant, DRY25, that showed extreme sensitivity to bleomycin. This mutant also exhibited hypersensitivity to hydrogen peroxide and t-butyl hydroperoxide, but showed no sensitivity to other DNA-damaging agents, including γ-rays, ultraviolet light, and methyl methanesulfonate. Subsequent analysis revealed that strain DRY25 was severely deficient in the repair of bleomycin-induced DNA lesions. Under normal growth conditions, DRY25 displayed a 3-fold increase in the frequency of chromosomal translocation that was further stimulated by 5- to 15-fold when the cells were treated with either bleomycin or hydrogen peroxide, but not by methyl methanesulfonate, as compared with the wild type. Genetic analysis indicated that the mutant defect was independent of the nucleotide excision, postreplication, or recombinational DNA-repair pathways. These data suggest that one conceivable defect of DRY25 is that it lacks a protein that protects the cell against oxidative damage to DNA. A clone that fully complemented DRY25 defect was isolated and the possible roles of the complementing gene are discussed.Key words: yeast, bleomycin, DNA repair, mutations.

Meiotic Crossing Over Between Nonhomologous Chromosomes Affects Chromosome Segregation in Yeast

Genetics ◽  
1997 ◽  
Vol 146 (1) ◽  
pp. 69-78
Author(s):  
Sue Jinks-Robertson ◽  
Shariq Sayeed ◽  
Tamara Murphy
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Chromosome Segregation ◽  
Meiotic Recombination ◽  
Southern Blot Analysis ◽  
Meiotic Chromosome ◽  
Crossing Over ◽  
Yeast Saccharomyces Cerevisiae ◽  
Reciprocal Translocations ◽  
Ectopic Recombination

Meiotic recombination between artificial repeats positioned on nonhomologous chromosomes occurs efficiently in the yeast Saccharomyces cerevisiae. Both gene conversion and crossover eventS have been observed, with crossovers yielding reciprocal translocations. In the current study, 5.5-kb ura3 repeats positioned on chromosomes V and XV were used to examine the effect of ectopic recombination on meiotic chromosome segregation. Ura+ random spores were selected and gene conversion vs. crossover events were distinguished by Southern blot analysis. Approximately 15% of the crossover events between chromosomes V and XV were associated with missegregation of one of these chromosomes. The missegregation was manifest as hyperploid spores containing either both translocations plus a normal chromosome, or both normal chromosomes plus one of the translocations. In those cases where it could be analyzed, missegregation occurred at the first meiotic division. These data are discussed in terms of a model in which ectopic crossovers compete efficiently with normal allelic crossovers in directing meiotic chromosome segregation.

Synaptic Structures in the Nuclei Of Sporulating Yeast, Saccharomyces Cerevisiae (Hansen)

1971 ◽  
Vol 9 (3) ◽  
pp. 665-677
Author(s):  
P. B. MOENS ◽  
E. RAPPORT
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Synaptonemal Complex ◽  
Chromosome Pairing ◽  
Meiotic Division ◽  
Meiotic Chromosome ◽  
Spherical Body ◽  
Sporulation Medium ◽  
Yeast Saccharomyces Cerevisiae ◽  
Amorphous Substance ◽  
Synaptic Structures

After 4 h on sporulation medium the larger cells have formed, within the nucleolus, a spherical body of amorphous substance which stains less densely than the nucleolus. At 8 h most of these bodies contain synaptonemal complex-like structures. There is usually only one such body per nucleus. Only rarely are normal synaptonemal complexes detectable in the nucleus. At the first meiotic division these bodies are still present but they no longer have polycomplexes associated with them. At this time they become sequestered in a nuclear evagination and they are no longer detectable after the second meiotic division. It is argued that the polycomplex body may elaborate synaptic elements which function in meiotic chromosome pairing but that the resulting complexes are difficult to detect because of the lack of chromosome condensation, a characteristic of several fungi.

scholarly journals Optimization of chemical mutagenesis of yeast Saccharomyces cerevisiae using ethyl methanesulfonate (EMS)

2015 ◽  
Vol 9 (3) ◽  
Author(s):  
Aleksandra Wawro ◽  
◽  
Adam Rzeszutek ◽  
Żaneta Bartkowiak ◽  
Dominika Pieprzyk-Kokocha ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethyl Methanesulfonate ◽  
Chemical Mutagenesis ◽  
Yeast Saccharomyces Cerevisiae

PREPARASI DEINOCOCCUS RADIODURANS DAN KHAMIR DALAM MATERIAL KECAP L-DRYING SEBAGAI BAHAN UJI PROFISIENSI

2016 ◽  
Vol 13 (1) ◽  
pp. 93
Author(s):  
Titin Yulinery ◽  
Ratih M.Dewi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Deinococcus Radiodurans ◽  
Test Preparation ◽  
Quality Parameters ◽  
Soy Sauce ◽  
Yeast Saccharomyces Cerevisiae ◽  
Microbiological Test ◽  
Bacterial Contaminants ◽  
Minimum Number ◽  
Important Quality

Tes kemampuan adalah salah satu kegiatan penting dalam pengendalian mutu dan jaminan kualitas mikrobiologi laboratorium untuk mengukur kompetensi analis dan analisis uji profisiensi membutuhkan persiapan Model mikroorganisme adalah kualitas standar dan validitas. Mikrobiologi uji kualitas produk kedelai utama diarahkan pada kehadiran Saccharomyces cerevisiae ragi (S. cerevisiae), S. Bailli, S. rouxii dankontaminan bakteri seperti Bacillus dan Deinococcus. Jenis ragi dan bakteri yang terlibat dalam proses dan dapat menjadi salah satu parameter kualitas penting dalam persiapan yang dihasilkan. Jumlah dan viabilitas bakteri dan ragi menjadi parameter utama dalam proses persiapan bahan uji. Jumlah tersebut adalah jumlah minimum yang berlaku dapat dianalisis. Jumlah ini harus dibawah 10 CFU diperlukan untuk menunjukkan tingkat hygienitas proses dan tingkat minimal kontaminasi. Viabilitas bakteri dan bahan tes ragi persiapan untuk tes kemahiran kecap yang diawetkan dengan L-pengeringan adalah teknik Deinococcus radiodurans (D. radiodurans) 16 tahun, 58 tahun S. cerevisiae, dan S. roxii 13 tahun. kata kunci: Viabilitas, Deinococcus, khamir, L-pengeringan, Proficiency AbstractProficiency test is one of the important activities in quality control and quality assurance microbiology laboratory for measuring the competence of analysts and analysis Proficiency test requires a model microorganism preparations are standardized quality and validity. Microbiological test of the quality of the main soy products aimed at thepresence of yeast Saccharomyces cerevisiae (S. cerevisiae), S. bailli, S. rouxii and bacterial contaminants such as Bacillus and Deinococcus. Types of yeasts and bacteria involved in the process and can be one of the important quality parameters in the preparation produced. The number and viability of bacteria and yeasts become themain parameters in the process of test preparation materials. The amount in question is the minimum number that is valid can be analyzed. This amount must be below 10 CFU required to indicate the level of hygienitas process and the minimum level of contamination. Viability of bacteria and yeast test preparation materials for proficiencytest of soy sauce that preserved by L-drying technique is Deinococcus radiodurans ( D. radiodurans ) 16 years, 58 years S. cerevisiae, and S. roxii 13 years. key words : Viability, Deinococcus, Khamir, L-drying, Proficiency

INTERACTION OF THE HIM1 GENE PRODUCT WITH HELICASES Srs2 (RadH) AND Mph1 YEAST SACCHAROMYCES CEREVISIAE

Tsitologiya ◽  
2018 ◽  
Vol 60 (7) ◽  
pp. 555-557 ◽  
Author(s):  
E. A. Alekseeva ◽  
◽  
T. A. Evstyukhina ◽  
V. T. Peshekhonov ◽  
V. G. Korolev ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Product ◽  
Yeast Saccharomyces Cerevisiae
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