Plectolyngbya hodgsonii: a novel filamentous cyanobacterium from Antarctic lakes

in Polar Biology (2011), 34

A special cluster of filamentous, false-branched cyanobacteria, isolated from littoral mat samples in coastal lakes of the Larsemann Hills region (coll. by D. Hodgson) was studied by a polyphasic approach ... [more ▼]

A special cluster of filamentous, false-branched cyanobacteria, isolated from littoral mat samples in coastal lakes of the Larsemann Hills region (coll. by D. Hodgson) was studied by a polyphasic approach. This morphotype has several characters corresponding to the traditional genera Leptolyngbya (morphology of trichomes), Pseudophormidium (type of false branching) or Schizothrix (occasional multiple arrangement of trichomes in the sheaths). However, this cluster of strains is distinctly isolated according to its phylogenetic position (based on 16S rRNA gene sequences), and thus, a separate generic classification is justified. The cytomorphology of this generic entity is also characteristic. Therefore, a new genus (Plectolyngbya with the type species P. hodgsonii) was described. [less ▲]

Plein de Soleils … à nos pieds

Learning material (2012)

Expérience: En nous promenant sous des feuillages en automne, au printemps ou en été, on peut apercevoir sur le sol plein de petits disques elliptiques plus ou moins lumineux qui ne sont rien d’autres que ... [more ▼]

Expérience: En nous promenant sous des feuillages en automne, au printemps ou en été, on peut apercevoir sur le sol plein de petits disques elliptiques plus ou moins lumineux qui ne sont rien d’autres que des images fidèles du Soleil projetées au travers de minuscules trous présents dans les feuillages des arbres ... [less ▲]

Pleiotropic drug sensitive mutants induced by insertional mutagenesis in Chlamydomonas

Poster (2000, May 05)

Pleiotropic Mutants Hypersensitive to Heavy Metals and to Oxidative Stress in Chlamydomonas Reinhardtii

in FEMS Microbiology Letters (2001), 196(2),

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 ... [more ▼]

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--6) of the following agents: cadmium, copper, lead, paraquat, hydrogen peroxide, UVC and light. In all mutants analyzed, the hypersensitive phenotype was most probably due to a single mutational event. The sensitivity of several pleiotropic mutants to a broad range of physical and chemical agents suggests that the disrupted genes are involved in multiple stress responses. [less ▲]

PLENA and FARINELLI: redundancy and regulatory interactions between two Antirrhinum MADS-box factors controlling flower development.

in EMBO Journal (1999), 18(14), 4023-34

We report the discovery of an Antirrhinum MADS-box gene, FARINELLI (FAR), and the isolation of far mutants by a reverse genetic screen. Despite striking similarities between FAR and the class C MADS-box ... [more ▼]

We report the discovery of an Antirrhinum MADS-box gene, FARINELLI (FAR), and the isolation of far mutants by a reverse genetic screen. Despite striking similarities between FAR and the class C MADS-box gene PLENA (PLE), the phenotypes of their respective mutants are dramatically different. Unlike ple mutants, which show homeotic conversion of reproductive organs to perianth organs and a loss of floral determinacy, far mutants have normal flowers which are partially male-sterile. Expression studies of PLE and FAR, in wild-type and mutant backgrounds, show complex interactions between the two genes. Double mutant analysis reveals an unexpected, redundant negative control over the B-function MADS-box genes. This feature of the two Antirrhinum C-function-like genes is markedly different from the control of the inner boundary of the B-function expression domain in Arabidopsis, and we propose and discuss a model to account for these differences. The difference in phenotypes of mutants in two highly related genes illustrates the importance of the position within the regulatory network in determining gene function. [less ▲]

La pleuropneumonie contagieuse bovine

in Vlaams Diergeneeskundig Tijdschrift (2000), 69

Pli et émotion. Remarques sur le problème de la socialisation chez Sartre et Merleau-Ponty

Conference (2004, November 23)

Pli, émotion et temporalité : remarques sur le problème de l’enfance chez Sartre et Merleau-Ponty

in Cormann, Grégory; Laoureux, Sébastien; Pieron, Julien (Eds.) Différence et identité. Les enjeux phénoménologiques du « pli » (2005)

Pline l’Ancien et l’art de la Renaissance. Balises pour une étude de réception entre le Nord et le Sud

in Revue Belge d'Archéologie et d'Histoire de l'Art (2006), 75

PlmA, a new member of the GntR family, has plasmid maintenance functions in Anabaena sp strain PCC 7120

in Journal of Bacteriology (2003), 185(15), 4315-4325

The filamentous cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 maintains a genome that is divided into a 6.4-Mb chromosome, three large plasmids of more that 100 kb, two medium-sized plasmids of 55 ... [more ▼]

The filamentous cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 maintains a genome that is divided into a 6.4-Mb chromosome, three large plasmids of more that 100 kb, two medium-sized plasmids of 55 and 40 kb, and a 5.5-kb plasmid. Plasmid copy number can be dynamic in some cyanobacterial species, and the genes that regulate this process have not been characterized. Here we show that mutations in an open reading frame, all1076, reduce the numbers of copies per chromosome of several plasmids. In a mutant strain, plasmids pCC7120delta and pCC7120zeta are both reduced to less than 50% of their wild-type levels. The exogenous pDU1-based plasmid pAM1691 is reduced to less than 25% of its wild-type level, and the plasmid is rapidly lost. The peptide encoded by all1076 shows similarity to members of the GntR family of transcriptional regulators. Phylogenetic analysis reveals a new domain topology within the GntR family. PlmA homologs, all coming from cyanobacterial species, form a new subfamily that is distinct from the previously identified subfamilies. The all1076 locus, named plmA, regulates plasmid maintenance functions in Anabaena sp. strain PCC 7120. [less ▲]