Etude de relations entre le mollusque Lymnaea truncatula Mueller et plusieurs parasites (Fasciola hepatica L., Muellerius capillaris Mueller, Neostrongylus linearis Marotel) au cours d'infestations mono- et bi-specifiques

SIGLEINIST T 71005 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

HEMANGIO-ENDOTHELIOME A CELLULES FUSIFORMES. A PROPOS D'UN CAS CLINIQUE. REVUE DE LA LITTERATURE

AMIENS-BU Santé (800212102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

(Gastropoda, Lymnaeidae): First findings on populations showing a single annual generation in lowland zones of central France

Three-year investigations were carried out in three populations of Galba truncatula to study their dynamics throughout the year when there was a single annual generation for the snail. These communities were living in permanently watered habitats, on acid soil and in lowland zones. In the three cases, egg-laying occurred from the end of June to the beginning of October and was closely associated with the summer fall in level and speed of running water. The highest numbers of egg-masses were noted at the end of July and the beginning of August. Newborns which hatched from these egg-deposits showed a strong decrease of their number from July to October and this diminution continues up to next June (at 3.4 snails per m2 of habitat). Juvenile snails measuring ≤ 2 mm in height were observed up to the end of next March. Compared to single annual generations of G. truncatula studied by other authors in zones of higher elevation, the longer period of egg-laying must be related to the local climatic and hydrologic conditions which are more favourable in lowlands than in elevation. The strong decrease in the number of snails throughout the year and the presence of a few ≤ 2-mm high juveniles during winter months might be explained by the characteristics of running water in these permanent habitats. Indeed, the high level and the great speed of running water during most months of the year would have an effect upon the number and the growth of these snails by causing unfavourable conditions for their life

The detection of snail host habitats in liver fluke infected farms by use of plant indicators.

International audienceField investigations in 361 liver fluke infected cattle- or sheep-breeding farms on acid soil were carried out during thirty years in March and April to record indicator plants in relation to the category of site colonized by the intermediate host of liver fluke, the snail Galba truncatula. Seven types of snail zones and six species of indicator plants were recorded in the 7709 positive sites studied. The most frequent habitats were located at the peripheral extremities of open drainage furrows. Juncus acutiflorus, Juncus effusus, Glyceria fluitans, and Agrostis stolonifera were the indicator plants. Plant indicators were highly efficient (38-80% of variance explained) when used with the size of site area within a hydrographical zone. The identification of positive sites for G. truncatula is a key for controlling the intermediate host on pastures through biological control with predatory molluscs. The positive sites may be detected using a two-step method including first categorization of hydrographical zones and then, within a zone, use of one or several indicator plants (frequently J. acutiflorus)

Use of Myriophyllum alterniflorum (Haloragaceae) for restoration of heavy-metal-polluted freshwater environments: preliminary results

International audienceMyriophyllum alterniflorum D.C., a poor-known aquatic macrophyte native to north-European freshwaters, was found even in polluted environments from the Vienne river and its tributaries which are often loaded with cadmium and copper near the Limoges metropolis (Haute-Vienne, France). This plant could cope with, to some extent, heavy-metal pollution and is used as a bioindicator since 2009. For these reasons, M. alterniflorum appears as a good candidate for running-freshwater restoration. In this way, the in vitro culture of this plant species was developed to allow a mass production and to study its phytoaccumulation capabilities. The in vitro culture of M. alterniflorum was optimized using Murashige & Skoog's medium allowing rapid growth and biomass production. Phytoaccumulation tests indicate that this species accumulate rapidly heavy metal as a 415-fold increase of cadmium and a 32-fold increase of copper were evidenced on the first 24h after contamination. Moreover, preliminary results concerning the reintroduction of M. alterniflorum clones in degraded and non-polluted areas are also rather encouraging, indicating that this taxon is a good candidate to freshwater restoration

Evidencing of copper impact on freshwater environments using Myriophyllum alterniflorum: restoration, biomonitoring, management

International audienceMyriophyllum alterniflorum D.C., an aquatic macrophyte native to north-European stream freshwaters, was found even in polluted environments from the Vienne river and its tributaries which are often loaded with anthropogenic copper in the Limousin region (France). Vitroplants of this species were reintroduced in degraded localities and the restoration was successful as insect larvae's, crawfishes, leeches and moderlieschen alevins were found in reintroduced macrophyte beds. Furthermore, the good in situ acclimation of the M. alterniflorum patches foresaw potential applications of biomonitoring. Indeed, this species is known to be heavy-metal tolerant and it appears as a good candidate to develop new plant biomarker models specific to pollution in stream environments as none were developed until now. Among ten physiological parameters studied during 35 days after in situ reintroduction, the photosynthetic pigments (chlorophylls a and b, and carotenoids) presented an excellent sensitivity to copper contamination. A strong correlation is obtained between pigment contents of M. alterniflorum and the copper water concentration. This allowed the establishment of models to estimate (i) the phytotoxicity of the heavy metal and (ii) the heavy-metal concentration from the pigment data. The accuracy of the models is limited to copper concentrations ranging from 0,07 µg.l-1 to 12,60 µg.l-1 hence offering many opportunities to apply this new method in a large quantity of European polluted stream waters while using expensive and complex analytical methodologies (e.g. ICP-MS). Owning biological and chemical information from this rapid and cost-effective approach, allows to develop environmental health programs to manage the heavy-metal load in stream ecosystems. Moreover, this study is a breakthrough in the biomonitoring of freshwaters as it leads to enhance environmental management program with the development of new biomarkers from freshwater macrophytes