Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : International audience
In this multidisciplinary study, we combined morphological, physiological, and phylogenetic approaches to identify three dominant water bloom-forming Cyanobacteria in a tropical marine mangrove in Guadeloupe (French West Indies). Phylogenetic analysis based on 16S rRNA gene sequences place these marine Cyanobacteria in the genera Oscillatoria (Oscillatoria sp. clone gwada, strain OG) or Planktothricoides (Candidatus Planktothricoides niger' strain OB and Candidatus Planktothricoides rosea' strain OP; both provisionally novel species within the genus Planktothricoides). Bioassays showed that Candidatus Planktothricoides niger' and Candidatus Planktothricoides rosea' are toxin-producing organisms. This is the first report of the characterization of Cyanobacteria colonizing periphyton mats of a tropical marine mangrove. We describe two novel benthic marine species and provide new insight into Oscillatoriaceae and their potential role in marine sulfide-rich environments such as mangroves.
ISSN: 0378-1097

hal-01536679
https://hal.archives-ouvertes.fr/hal-01536679
DOI : 10.1111/1574-6968.12551

Éditeur(s) : HAL CCSD Paris : Muséum national d'histoire naturelle
Résumé : International audience
To increase understanding of the chromosomal diversity among cichlid species, karyotypes of 19 species of Cichlidae belonging to 15 genera (Paratilapia polleni, Chromidotilapia guntheri guntheri, Hemichromis fasciatus, Steatocranus irvinei, Stomatepia pindu, Altolamprologus compressiceps, Julidochromis transcriptus, Neolamprologus tetracanthus, N. brevis, Gnathochromis permaxillaris, Eretmodus cyanostictus, Astatoreochromis alluaudi, Haplochromis callipterus, H. paludinosus, Ninzbochromis livingstonii, N. polystigma, Pseudocrenilabrus multicolor victoriae, P. philander and Ctenochromis horei) were investigated for the first time. In spite of the variation in the karyotypes of cichlid fishes (from 2n = 42 to 2n = 48 chromosomes), the modal chromosome number was 2n = 44. Cytogenetic mapping of the 18S ribosomal RNA (18S rRNA) gene was accomplished.
ISSN: 0399-0974

hal-01544902
https://hal.archives-ouvertes.fr/hal-01544902

Éditeur(s) : HAL CCSD Paris : Muséum national d'histoire naturelle
Résumé : International audience
The chromosomal diversity within six species of Mormyridae belonging to six different genera (Gnathonemus petersii, Marcusenius moorii, Ivindomyrus obdenboschi, Brienomyrus sp., Stomatorhinus walkeri and Petrocephalus microphthalmus) is investigated for the first time. These species have a conserved diploid chromosome number of 2n = 50 (except G. petersii 2n = 48) but different chromosome formulae, essentially involving pericentric inversions. C-banding has been used for the localization of heterochromatin. For a deeper interspecific comparison, several molecular markers were localized in the chromosomes by fluorescence in situ hybridization (FISH): a 18S rDNA probe; a microsatellite probe (GAA)(10), and a telomeric probe (TTAGGG)(7). The distribution of the 18S rDNA patterns, in particular, shows an amazing specific diversity, confirming a rapid radiation accompanied by major chromosome rearrangements.
ISSN: 0399-0974

hal-01544756
https://hal.archives-ouvertes.fr/hal-01544756