"LOVE TO HATE" pesticides: felicity or curse for the soil microbial community? An FP7 IAPP Marie Curie project aiming to establish tools for the assessment of the mechanisms controlling the interactions of pesticides with soil microorganisms.

Pesticides end up in soil where they interact with soil microorganisms in various ways. On the Yin Side of the interaction, pesticides could exert toxicity on soil microorganisms, while on the Yang side of interaction, pesticides could be used as energy source by a fraction of the soil microbial community. The LOVE TO HATE project is an IAPP Marie Curie project which aims to study these complex interactions of pesticides with soil microorganisms and provide novel tools which will be useful both for pesticide regulatory purposes and agricultural use. On the Yin side of the interactions, a new regulatory scheme for assessing the soil microbial toxicity of pesticides will be proposed based on the use of advanced standardized tools and a well-defined experimental tiered scheme. On the Yang side of the interactions, advanced molecular tools like amplicon sequencing and functional metagenomics will be applied to define microbes that are involved in the rapid transformation of pesticides in soils and isolate novel pesticide biocatalysts. In addition, a functional microarray has been designed to estimate the biodegradation genetic potential of the microbial community of agricultural soils for a range of pesticide groups.

Correction of bilirubin conjugation in the Gunn rat using hepatocytes immobilized in alginate gel beads as an extracorporeal bioartificial liver.

A new extracorporeal bioartificial liver using alginate-entrapped hepatocytes was developed and evaluated for its ability to correct the lack of bilirubin conjugation in the Gunn rat. Hepatocytes were harvested from Sprague-Dawley rats by the two-step collagenase perfusion method and then immobilized in Ca(++)-alginate beads. The ability of immobilized hepatocytes to conjugate bilirubin was investigated in vitro by comparison with hepatocyte monolayer cultures. The bioartificial liver consisted of a cylindric bioreactor containing either alginate beads with hepatocytes (test group) or alginate beads alone (control group). Gunn rats were connected to this bioreactor via an extracorporeal circulation and bile fractions were collected at hourly intervals. Both bilirubin monoconjugates and bilirubin diconjugates were measured in the bile by high pressure liquid chromatography. Hepatocyte viability in alginate beads was determined prior to and at the end of each experiment and found to be unchanged (75%). In the test group, the concentration of bilirubin conjugates increase rapidly, attaining median values of 72.26 microM and 92.59 microM for mono and diconjugated bilirubin respectively, during a 3 h period of extracorporeal circulation. In the control group, the levels of either conjugate did not exceed 0.87 microM throughout the experiments. Statistical analysis showed a significant difference between the two groups (p < 0.0023). These results suggest that the bioartificial liver used in this study represents an effective method for the temporary correction of the Gunn rat's genetic defect. Such a system might be of therapeutic interest in acute liver failure.

[Extracorporeal bio-artificial liver using isolated hepatocytes. An experimental study in the rat]. / Foie bioartificiel extracorporel utilisant des hépatocytes isolés. Etude expérimentale chez le rat.

A new type of bioartificial liver using isolated hepatocytes immobilized in alginate beads was developed and its capacity of correcting the metabolic deficiency of bilirubin conjugation in Gunn rats was assessed. Hepatocytes were isolated from Sprague-Dawley rats using the in situ collagenase perfusion technique, and they were then immobilized in Calcium alginate beads. The capacity of these immobilized hepatocytes to conjugate in vitro bilirubin was checked as compared to monolayer hepatocyte culture. The bioartificial liver consisted in a cylindrical bioreactor containing either alginate beads and hepatocytes (test group), or only alginate beads (control group). Gunn rats were connected to this bioreactor through and extracorporeal circulation system, and "bile samples were collected" every hour. Bilirubin mono and biconjugates were dosed in the bile using the high-performance liquid chromatography technique. The viability of alginate immobilized hepatocytes, determined before and after each experiment, was stable at 75%. In the test group, the total conjugate concentration rapidly increased to reach a maximum value of 204 +/- 16 microns after 3 hours, while in the control group, there were only conjugate traces (1 micron). These results show that the bioartificial liver is an efficient means to temporarily correct genetic deficiency in Gunn rats. Such a system could be of therapeutic interest in case of acute hepatic insufficiency.