The cytoplasmic ribosomes of Chlamydomonas reinhardtii: Characterization of antibiotic sensitivity and cycloheximide-resistant mutants

1987 ◽  
Vol 210 (3) ◽  
pp. 419-428 ◽  
Author(s):  
G. H. Fleming ◽  
J. E. Boynton ◽  
N. W. Gillham
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Antibiotic Sensitivity ◽  
Resistant Mutants ◽  
Cytoplasmic Ribosomes

scholarly journals Characterization of cytoplasmic and nuclear genomes in the colorless alga Polytoma. II. General characterization of organelle nucleic acids.

1976 ◽  
Vol 69 (2) ◽  
pp. 371-382 ◽  
Author(s):  
C Siu ◽  
H Swift ◽  
K Chiang
Keyword(s):  
Nucleic Acids ◽  
Chlamydomonas Reinhardtii ◽  
Ribosomal Rna ◽  
Base Composition ◽  
Buoyant Density ◽  
Main Band ◽  
Major Species ◽  
A Minor ◽  
Cytoplasmic Ribosomes

Polytoma obtusum has a main band DNA (alpha) with a buoyant density in CsC1 of rho = 1.711 g/ml and a light DNA satellite (beta) with rho = 1.682 g/ml. beta-DNA was substantially enriched in a fraction containing small leucoplast fragments and some mitochondria, which was obtained in a pellet sedimenting between 3,000 g and 5,000 g. A crude mitochondrial pellet was also obtained by sedimenting at 12,000 g to recover particulates remaining in the supernate after 10 min at 5,000 g. This fraction contained a third DNA component (gamma) with rho = 1.714 g/ml. We have concluded that the leucoplasts of P. obtusum contain the beta-DNA (1.6882) and the mitochondria possess the gamma-component (1.714). Two distinct classess of ribosomes were isolated and separated by sucrose density gradients, a major 79S species and a minor species at 75S. The major species possessed the 25S and 18S ribosomal RNA (rRNA), characteristic of cytoplasmic ribosomes, and these particles co-sedimented in sucrose gradients with the 79S cytoplasmic ribosomes of Chlamydomonas reinhardtii. The minor species was present in about 2% of the total ribosomal population but showed an eight-to-ninefold enrichment in the leucoplast pellet, suggesting that it was of organelle origin. These 73S particles had RNA components migrating very closely with the 18S and 25S species of the 79S ribosomes, but the base composition of the rRNA from these two classes of ribosomes was significantly different; the rRNA from the 79S ribosomes had a G+C mole ratio of 50.0%, while the rRNA from the 73S class had a ratio of 47.5%. By comparison, chloroplast ribosomes of C. reinhardtii were found to sediment at 70S and contain rRNA molecules of 23S and 16S, with a G + C content of 51.0%. These findings support the concept that the Polytoma leucoplast possesses characteristic genetic and protein-forming systems.

scholarly journals Isolation and Characterization of Arsenate-Sensitive and Resistant Mutants of Chlamydomonas reinhardtii

2000 ◽  
Vol 41 (1) ◽  
pp. 77-83 ◽  
Author(s):  
S. Fujiwara ◽  
I. Kobayashi ◽  
S. Hoshino ◽  
T. Kaise ◽  
K. Shimogawara ◽  
...  
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Isolation And Characterization ◽  
Resistant Mutants

Mutants of Chlamydomonas reinhardtii Deficient in Mitochondrial Complex I: Characterization of Two Mutations Affecting the nd1 Coding Sequence

Genetics ◽  
2001 ◽  
Vol 158 (3) ◽  
pp. 1051-1060
Author(s):  
Claire Remacle ◽  
Denis Baurain ◽  
Pierre Cardol ◽  
René F Matagne
Keyword(s):  
Mitochondrial Genome ◽  
Chlamydomonas Reinhardtii ◽  
Complex I ◽  
Slow Growth ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Sequencing Analysis ◽  
Mitochondrial Complex ◽  
Genetical Analysis ◽  
Complex I Activity

Abstract The mitochondrial rotenone-sensitive NADH:ubiquinone oxidoreductase (complex I) comprises more than 30 subunits, the majority of which are encoded by the nucleus. In Chlamydomonas reinhardtii, only five components of complex I are coded for by mitochondrial genes. Three mutants deprived of complex I activity and displaying slow growth in the dark were isolated after mutagenic treatment with acriflavine. A genetical analysis demonstrated that two mutations (dum20 and dum25) affect the mitochondrial genome whereas the third mutation (dn26) is of nuclear origin. Recombinational analyses showed that dum20 and dum25 are closely linked on the genetic map of the mitochondrial genome and could affect the nd1 gene. A sequencing analysis confirmed this conclusion: dum20 is a deletion of one T at codon 243 of nd1; dum25 corresponds to a 6-bp deletion that eliminates two amino acids located in a very conserved hydrophilic segment of the protein.

Characterization of sparfloxacin-resistant mutants of Staphylococcus aureus obtained in vitro

2001 ◽  
Vol 18 (2) ◽  
pp. 107-112 ◽  
Author(s):  
Joaquim Ruiz ◽  
Josep M. Sierra ◽  
M.Teresa Jiménez De Anta ◽  
Jordi Vila
Keyword(s):  
Staphylococcus Aureus ◽  
Resistant Mutants
Sign in / Sign up

Export Citation Format

Share Document