Fur (Ferric uptake regulator) is a DNA-binding protein which represses the transcription of iron-regulated promoters using Fe2+ as a cofactor. In Gram negative bacteria, fur controls the expression of toxins and virulence factors when facing iron-stress. Iron is a key element limiting the growth and proliferation of phytoplankton. We have cloned the fur-gene from the cyanobacterium Synechococcus PCC 7942, applying the polymerase chain reaction (PCR) technique. The DNA fragments amplified encodes a Fur-type protein, which conserves the main motifs found in the family of Fur proteins. Recombinant Fur protein was successfully overproduced, reaching about 15 % of the total protein content. Also, a Fur protein was identified in the filamentous, nitrogen-fixing cyanobacterium Anabaena PCC 7120.

The Oued Mellah reservoir (33°30' N-07°20' W) is a shallow brackish lake located 25 km North of Casablanca. A study of the phytoplankton community of this lake shows that it is affected by potentially toxic blooms of Cyanobacteria and Haptophyceae. Microcystis ichthyoblabe (first time recorded from Morocco), Anabaena aphanizomenoides, Oscillatoria chlorina (Cyanobacteria) and Prymnesium parvum (Haptophyceae) constitute the dominant phytoplankton taxa. M. ichthyoblabe starts its growth in late spring. In 1999, it formed a spectacular bloom during May-June, invading the lake with a maximal biomass of 298 mgFW.L-1. This proliferation coincided with high temperatures, strong luminous intensity, alkaline pH and low to undetectable contents of nitrates and orthophosphates. The toxicity of the M. ichthyoblabe bloom material was first determined by mouse bioassay. Bloom material collected during the maximal development phase has an LD50 about 502 mgDW.Kg-1. Hepatotoxicity was confirmed by histopathological study. The total contents of microcystins determined by ELISA technique both for bloom material and the isolated strain are about 0.79 and 5.4 µg.gDW -1 respectively. Analysis by HPLC-PDA allows the detection of 11 variants of microcystins. The use of the microcystin-LR authentic sample showed the absence of this microcystin variant in the samples analysed.

The distribution and ecological data base of Vaucheria bursata, V. frigida, V. geminata, V. racemosa, V. erytrospora, V. canalicularis,and V. debaryana occurring in streams of the Kraków-Czestochowa Upland (Poland) are provided.

Experimental introductions of Galba truncatula in new habitats were carried out over the 30 last years in the department ofHaute-Vienne (central France) to study the details of snail settlement and the outcome of these populations, and to determine ifthe susceptibility of these new colonies to experimental infection with Fasciola hepática did not change over time. A total of 51samples (100 adult snails each) were collected from three populations known for their high susceptibility to F hepatica infections (> 60 %). Each sample was introduced in March in an open drainage furrow (36 meadows) or a road ditch (15 sites) whichhad never been inhabited by snails. Introduced snails from 22 samples survived in 9 furrows and 13 road ditches. In these sites,the number of overwintering G. truncatula increased up to the-second or third year post-introduction and progressively decreasedin the following years to become stable from the sixth or seventh year (less than 40 snails per site). In 13 populations (outof 22), experimental infections of snails with F. hepatica did not result in significant variations in survival rates or in prevalencesof infections when compared to the respective rates recorded in the three original populations. Conversely, in the nine otherpopulations, experimental infections of snails resulted in a decrease in prevalence (< 40 %), whereas the survival rates of snailsat day 30 post-exposure did not change. This last result might be explained by a change in natural parasite pressure in the newhabitats, being probably lower than that existing in the three sites inhabited by the populations of origin.

The discovery of male larvae from Madagascar [only a female larva was known so far] confirm their identification to the familyTeloganodidae and genus Manohyphella Allen, due to their dioptic compound eyes. Generic level characterization and intergenericcomparisons are given for the first time. In addition, two new species are described from larvae : Manohyphellasphyxia, n. sp. and M. animosa, n. sp. Cladistic analysis shows Manohyphella to represent a basal branch of a clade that includesall Teloganodidae except Ephemerellina Lestage and that it is closest in grade to the southern African genus Nadinetella McCafferty& Wang. Historical biogeographic relationships with regard to Gondwana and the trans-Indian Ocean track are discussed.Larvae were abundant on stones in current in a protected forest stream in Ranomafana National Park in eastern Madagascar butwere at significantly lower densities in five other area streams, including three in the park's agriculture peripheral zone. The relativelyundisturbed condition of the stream where they were found in abundance may in part account for such distribution ; however,gradient characteristics of the stream that produce waterfalls were also typical of habitats documented for other Teloganodidae.The diet of Manohyphella consists mainly of fine detritus. Feeding data from other ephemerelloids are compared, andmaxillary morphology appears well adapted for brushing and scraping.

A checklist of Corsica's lotic Chironomidae is given. Collections of pupal exuviae from 32 river sites (July 1995, May 1999)yielded a total of 147 species-level taxa including several previously unknown pupal exuviae. Three of them are figured? Hayesomyia Pe nov., Eukiefferiella Pe nov., Thienemanniella Pe nov. These unusual forms may possibly be endemic speciesto Corsica that are new to science. Most of the chironomid species recorded are western Palaearctic. 11 species are circum-mediterranean.

Le but de cette étude est de mieux connaître la qualité de l'eau et la macrofaune benthique des cours d'eau marocains duMoyen-Atlas. L'Oued Tizguit a été choisi pour son accessibilité et la variété de son environnement. Onze stations ont été suiviesen mesurant 8 paramètres physico-chimiques et en faisant l'inventaire faunistique pendant un cycle hydrologique.Ce travail montre que la qualité de l'eau évolue dans le temps selon un gradient amont-aval.Des prélèvements qualitatifs ont permis de dénombrer 167 taxons appartenant à différents groupes où les Coléoptères sontmajoritaires. La distribution de cette macrofaune semble déterminée par la variation longitudinale des différents paramètres dumilieu, et sa composition doit son originalité, en partie, à la qualité de l'eau du milieu.