Numerous previous studies have elucidated 2 surprising patterns of spliceosomal intron evolution in diverse eukaryotes over the past roughly 100 Myr. First, rates of recent intron gain in a wide variety of eukaryotic lineages have been surprisingly low, far too low to explain modern intron densities. Second, intron losses have outnumbered intron gains over a variety of lineages. For several rea...

Genetic analysis has revealed that the accumulation of several chloroplast mRNAs of the green alga Chlamydomonas reinhardtii requires specific nucleus-encoded functions. To gain insight into this process, we have cloned the nuclear gene encoding the Mbb1 factor by genomic rescue of a mutant specifically deficient in the accumulation of the mRNAs of the psbB/psbT/psbH chloroplast transcription u...

The precursor of the ribulose-1,5-bisphosphate carboxylase small subunit and other proteins from Chlamydomonas reinhardtii are efficiently transported into chloroplasts isolated from spinach and pea. Thus, similar determinants specify precursor-chloroplast interactions in the alga and vascular plants. Removal of all or part of its transit sequence was found to block import of the algal small su...

Insertional mutagenesis was used in Chlamydomonas reinhardtii to isolate original mutants hypersensitive to multiple drugs and physical agents. Out of 5200 transformants analyzed, 13 mutants belonging to seven phenotypic classes were isolated. Five were exclusively sensitive to cadmium and represented two loci. The other mutants were pleiotropic and presented a cross sensitivity to several (2--...

Chlamydomonas reinhardtii, a unicellular green alga, has been used in bioassay detection of a variety of toxic compounds such as pesticides and toxic metals, but mainly using liquid culture systems. In this study, an algal lawn-agar system for semi-quantitative bioassay of herbicidal activities has been developed. Sixteen different herbicides belonging to 11 different categories were applied to...

Blue light as an environmental cue plays a pivotal role in controlling the progression of the sexual life cycle in the green alga Chlamydomonas reinhardtii. Phototropin was considered a prime candidate for the blue-light receptor involved. By using the RNA interference method, knockdown strains with reduced phototropin levels were isolated. Those with severely reduced levels of this photorecept...

The eyespot of the unicellular green alga Chlamydomonas reinhardtii is a photoreceptive organelle required for phototaxis. Relative to the anterior flagella, the eyespot is asymmetrically positioned adjacent to the daughter four-membered rootlet (D4), a unique bundle of acetylated microtubules extending from the daughter basal body toward the posterior of the cell. Here, we detail the relations...

A new biosensor was designed for the assessment of aquatic environment quality. Three microalgae were used as toxicity bioindicators: Chlorella vulgaris, Pseudokirchneriella subcapitata and Chlamydomonas reinhardtii. These microalgae were immobilized in alginate and silica hydrogels in a two step procedure. After studying the growth rate of entrapped cells, chlorophyll fluorescence was measure...

The light environment controls the swimming of microalgae through a light-seeking and avoiding behaviour, which is known as phototaxis. In this work, we exploit phototaxis to control migration concentration populations soil microalga Chlamydomonas reinhardtii . By imaging suspension these in cuvette illuminated from above by blue light, study how changes stability demonstrate thin, porous layer...

Abstract Despite being an essential micronutrient, copper is also a potentially toxic heavy metal. Using selection experiments, we produced Chlamydomonas reinhardtii populations with increased tolerance of ions and then derived pure cell lines from these populations. Strains the same population (both adapted nonadapted) significantly differed in terms growth parameters. Cultivation strains rang...